CN213776234U

CN213776234U - Planetary gear device, equipment for inhibiting noise generation thereof and actuator

Info

Publication number: CN213776234U
Application number: CN202021566436.4U
Authority: CN
Inventors: 河田敏树; 石田翔平; 金子拓也
Original assignee: Enplas Corp
Current assignee: Enplas Corp
Priority date: 2019-08-02
Filing date: 2020-07-31
Publication date: 2021-07-23
Anticipated expiration: 2030-07-31
Also published as: JP7431564B2; JP2021025646A; JP7376353B2; JP2021025649A; CN213017523U; JP2021025650A; JP7418192B2; JP7450391B2; JP2021025645A; JP7402682B2; CN213017522U; JP2021025648A; JP2021025644A; JP7348825B2; CN213419795U

Abstract

The present application provides an apparatus for suppressing noise generated in a planetary gear device, including: an internal gear having an inner peripheral surface on which an internal tooth portion is formed; the internal gear has an outer peripheral surface having a convex portion formed on at least a part thereof in a direction from one side to the other side in an axial direction of the internal gear, the internal gear having an open end surface extending between an inner peripheral surface and an outer peripheral surface on an end portion on the other side of the internal gear; a substantially cylindrical housing for accommodating the internal gear, the movement of the internal gear in the circumferential direction within the housing being restricted by contact with a convex portion of the internal gear, the housing having a contact surface portion provided to face an opening end surface on the other side of the internal gear, and the opening end surface on the other side of the internal gear having a contact portion protruding toward the contact surface portion side, the movement of the internal gear toward the contact surface portion side being restricted by contact with the contact surface portion in the axial direction.

Description

Planetary gear device, equipment for inhibiting noise generation thereof and actuator

Technical Field

The utility model relates to an equipment, planetary gear device and actuator for suppressing the noise that produces in planetary gear device.

Background

Planetary gear devices are used in a variety of technologies such as automobiles, robots, and the like. Since the planetary gear device is constructed by a combination of a plurality of gears, noise and vibration may be generated during operation. Techniques for suppressing the generation of noise and vibration when the planetary gear device is operated have been proposed.

As one of such proposed techniques, patent document 1 discloses a planetary gear device having a structure that separates an internal gear and a housing so that there is a gap between the internal gear and the housing. The use of the structure in which the internal gear and the housing are separated makes it more difficult for vibration to be transmitted from the internal gear to the housing, thereby reducing noise generated by the vibration.

[ Prior art reference)]

[ patent document ]]

[ patent document 1] Japanese unexamined patent application publication H6-74835

SUMMERY OF THE UTILITY MODEL

[ problem to be solved by the present invention]

In the planetary gear device of patent document 1, the outer peripheral surface of the internal gear and the inner peripheral surface of the housing are formed with shapes that fit together. Therefore, when the internal gear moves during the operation of the planetary gear device, there is contact between the outer peripheral surface of the internal gear and the inner peripheral surface of the housing, and the contact range has a certain degree of width. Thus, in a state in which there is contact between the internal gear and the housing, the vibration of the planetary gear mechanism, which is propagated to the internal gear, is easily transmitted to the housing, and therefore there is a problem: planetary gear devices also have a tendency to generate noise.

The present invention is intended to solve the problem field such as described above, and an object is to provide a separate structural unit for an internal gear and a housing, capable of suppressing transmission of vibration from a planetary gear mechanism and noise generated by a planetary gear device, and capable of providing a planetary gear device equipped with the separate structural unit and an actuator equipped with the planetary gear device.

[ means for solving the problems ]]

According to the utility model discloses an equipment for suppressing noise that produces in planetary gear device, include: an internal gear having: having an inner peripheral surface on which an internal tooth portion is formed; wherein the internal gear has an outer peripheral surface having a convex portion formed on at least a part thereof in a direction from one side to the other side in an axial direction of the internal gear, and wherein the internal gear has an open end surface extending between the inner peripheral surface and the outer peripheral surface on an end portion on the other side of the internal gear; and a substantially cylindrical housing for accommodating the internal gear, wherein movement of the internal gear in a circumferential direction within the housing is restricted by contact with the convex portion of the internal gear, wherein the housing has a contact surface portion provided to face the opening end surface on the other side of the internal gear, and wherein the opening end surface on the other side of the internal gear has a contact portion protruding toward a contact surface portion side, wherein the contact portion restricts movement of the internal gear toward the contact surface portion side by contact with the contact surface portion in the axial direction.

In some embodiments, the contact portion includes at least three contact convex portions making point contact with the contact surface portion.

In some embodiments, the contact portion includes a plurality of contact portions protruding from the contact surface portion side, and wherein the plurality of contact portions are provided on the opening end face at equal intervals in the circumferential direction.

In some embodiments, the contact portion includes a plurality of contact portions protruding from the contact surface portion side, and wherein the plurality of contact portions are provided at unequal intervals in the circumferential direction on the opening end face.

In some embodiments, the contact portion is configured such that the area of a cross section perpendicular to the axial direction thereof is smaller the farther away from the opening end surface of the other side.

In some embodiments, the contact portion is a pyramid or a conical body, wherein a tip portion of the contact surface portion side is a top.

In some embodiments, in the contact portion, the tip portion of the contact surface portion has a spherical surface shape.

In some embodiments, the contact portion has a rod-like extension portion extending from the opening end face toward the contact surface portion, and a hemispherical surface portion provided on the tip of the extension portion.

In some embodiments, the contact portion has a cross-sectional shape that is a plus sign shape in the cross-section perpendicular to the axial direction.

In some embodiments, the second contact portion is provided to protrude from the one side on the opening end face on the one side.

In some embodiments, the internal gear and the housing are made of synthetic resin, and wherein the internal gear is formed of synthetic resin having a hardness smaller than that of the synthetic resin used to form the housing.

According to the utility model discloses a planetary gear device, include: a device for suppressing noise generated in the planetary gear device; at least one planetary gear meshed with the internal gear; a sun gear meshed with the at least one planetary gear and positioned at a radial center along the housing; and a carrier rotatably supporting the one or more planet gears.

In some embodiments, the planetary gear device further comprises: a second sun gear that rotates with rotation of the carrier; one or more second planet gears disposed on a periphery of the second sun gear and meshed with the second sun gear; a second carrier rotatably supporting the one or more second planet gears; and a second housing having internal teeth engaged with the one or more second planetary gears formed on an inner peripheral surface thereof, wherein the housing and the second housing are integrally formed.

According to the utility model discloses a planetary gear device, including at least two-stage planetary gear mechanism, every level planetary gear mechanism includes: a sun gear; one or more planet gears arranged on the periphery of the sun gear for meshing with the sun gear; and a carrier rotatably supporting the one or more planetary gears, wherein in the at least two-stage planetary gear mechanism, a planetary gear mechanism operating at a highest speed includes an apparatus for suppressing noise generated in a planetary gear device, wherein the one or more planetary gears of the planetary gear mechanism are engaged with the internal gear, and wherein in the at least two-stage planetary gear mechanism, a planetary gear mechanism operating at a lowest speed includes a housing including internal teeth formed on an inner peripheral surface thereof and engaged with the one or more planetary gears of the planetary gear mechanism.

According to the utility model discloses an actuator of planetary gear device, include: a planetary gear device; and a motor connected to the planetary gear arrangement for driving the planetary gear arrangement.

The separate structural unit for the internal gear and the housing comprises: an internal gear having a first convex portion formed on the outer peripheral surface, the first convex portion extending from one side to the other side in the axial direction; and a housing, wherein a second convex portion extending from one side to the other side in the axial direction is formed on the inner peripheral surface, and the housing accommodates the internal gear in a state in which a gap with the inner peripheral surface exists, wherein: the movement of the inner gear within the interior of the housing is limited by the line contact between the first and second raised portions.

Of the first and second convex portions, one convex portion may be formed as a pair having a space therebetween, and the other convex portion may be provided so as to be interposed between the one convex portion formed as a pair; and at least one of the contact position of the one convex portion and the contact position of the other convex portion, which are in line contact with each other, may be a curved surface.

The one convex portion may be the second convex portion, and the other convex portion may be the first convex portion; and when taken by a plane perpendicular to the axial direction, the first convex portion may have a triangular cross section, and the first convex portion may line-contact the second convex portion at an inclined surface formed in the plane.

One of the contact position of the first convex portion and the contact position of the second convex portion that are in line contact with each other may be a convex curved surface, and the other contact position may be a flat surface.

The contact position of the first convex portion and the contact position of the second convex portion that are in line contact with each other may be a convex curved surface.

One of the contact position of the first convex portion and the contact position of the second convex portion that are in line contact with each other may be a convex curved surface, and the other contact position may be a concave curved surface.

The internal gear and the housing may be made of synthetic resin; and the internal gear may be formed of a synthetic resin having a hardness smaller than that of the synthetic resin for forming the housing.

According to the utility model discloses a constitutional unit that is used for separation of internal gear and casing includes: an internal gear having: an inner peripheral surface on which an internal tooth portion is formed; an outer peripheral surface on which a convex portion is formed, at least a part of the convex portion being in a direction from one side to the other side in the axial direction; and an open end face extending between the inner peripheral surface and the outer peripheral surface on the end portion on the other side; and a cylindrical housing for accommodating the internal gear, wherein movement of the internal gear in a circumferential direction within the housing is restricted by contact with the convex portion of the internal gear, wherein: the housing has a contact surface portion provided to face the opening end surface on the other side of the internal gear; and the opening end surface on the other side has a contact portion protruding toward the contact surface portion side, wherein the contact portion restricts movement of the internal gear toward the contact surface portion side by contact with the contact surface portion in the axial direction.

According to the utility model discloses a planetary gear device includes: the separate structural units for the internal gear and the housing as described above; one or more planet gears meshed with the internal gear; a sun gear meshed with the one or more planet gears, positioned at a center of the one or more planet gears; and a carrier rotatably supporting the one or more planet gears.

The structure may further include a second sun gear that rotates similarly to the rotation of the carrier as the carrier rotates; one or more second planet gears disposed on a periphery of and meshed with the second sun gear; a second carrier rotatably supporting one or more second planetary gears; and a second housing having internal teeth that mesh with the one or more second planetary gears formed on an inner peripheral surface thereof, wherein: the housing and the second housing may be integrally formed.

According to the utility model discloses a planetary gear device includes: at least two-stage planetary gear mechanism, each stage planetary gear mechanism includes: a sun gear; one or more planet gears arranged on the periphery of the sun gear for meshing with the sun gear; and a carrier rotatably supporting the one or more planet gears, wherein: in the at least two-stage planetary gear mechanism, the planetary gear mechanism operating at the highest speed comprises a separate structural unit for the annulus gear and the housing as described above, wherein the one or more planet gears of the planetary gear mechanism mesh with the annulus gear; and in the at least two-stage planetary gear mechanism, the planetary gear mechanism that operates at the lowest speed includes a housing in which internal teeth that mesh with the one or more planetary gears of the planetary gear mechanism are formed on the inner peripheral surface.

According to the utility model discloses an actuator includes: the planetary gear device as described above; and a motor connected to the planetary gear arrangement for driving the planetary gear arrangement.

[ effects of the present invention]

In the present invention, the contact range between the internal gear and the housing is narrower than that in the prior art, thereby reducing the transmission of vibration caused by the planetary gear mechanism to the housing. This can suppress transmission of vibration from the planetary gear mechanism, and can suppress noise generated by the planetary gear device accompanying the vibration of the planetary gear mechanism.

[ problem ] to]

In order to provide a separate structural unit for the annulus gear and the housing, said structural unit makes it possible to suppress the transmission of vibrations from the planetary gear mechanism and to suppress noise generated by the planetary gear arrangement.

[ solving means ]]

An internal gear having: an inner peripheral surface on which an internal tooth portion is formed; an outer peripheral surface on which a convex portion is formed, at least a part of the convex portion being in a direction from one side to the other side in the axial direction; and an open end face extending between the inner peripheral surface and the outer peripheral surface on an end portion on the other side; and a cylindrical housing for accommodating the internal gear, wherein movement of the internal gear in a circumferential direction within the housing is restricted by contact with the convex portion of the internal gear, wherein: the housing has a contact surface portion provided to face the opening end surface on the other side of the internal gear; and the opening end surface on the other side has a contact portion protruding toward the contact surface portion side, wherein the contact portion restricts movement of the internal gear toward the contact surface portion side by contact with the contact surface portion in the axial direction.

Drawings

Fig. 1 is a perspective view of an actuator according to an embodiment of the present invention.

Fig. 2 is a front view of the actuator as viewed from an arrow AII in fig. 1.

Fig. 3 is a cross-sectional view of the actuator taken on the section line III-III in fig. 2.

Fig. 4 is an assembled perspective view of an actuator according to an embodiment according to the present invention.

Fig. 5 is a cross-sectional view of a second housing according to an embodiment according to the present invention.

Fig. 6 is a perspective view of a second housing according to an embodiment according to the present invention.

Fig. 7 is a perspective view of a first planetary gear mechanism according to an embodiment in accordance with the present invention.

Fig. 8 is a perspective view of a second planetary gear mechanism according to an embodiment in accordance with the present invention.

Fig. 9 is a diagram for explaining a relationship between a second housing and an internal gear according to an embodiment of the present invention.

Fig. 10 is an explanatory diagram focusing on the stopper formed in the second housing shown in fig. 9.

Fig. 11 is an explanatory diagram focusing on the movement restricting convex portion formed on the internal gear shown in fig. 9.

Fig. 12 is a view for explaining a state in which the internal gear shown in fig. 9 is in contact with the second housing by rotation around the axis.

Fig. 13 is a view for explaining a state of contact with the second housing by movement of the internal gear shown in fig. 9 in a direction perpendicular to the axis.

Fig. 14 is a diagram for explaining a state of contact between the second housing and the internal gear when viewed from an arrow XIV in fig. 12.

Fig. 15 is a schematic diagram comparing the movement restricting convex portion shown in fig. 11 with another example of the movement restricting convex portion.

Fig. 16 is an explanatory diagram focusing on a contact position between an internal gear and a second housing according to another embodiment of the present invention.

Fig. 17 is a diagram accompanying the explanation of a first modified example of an internal gear according to an embodiment of the present invention, in which fig. 17A is a rear view of the internal gear as the first modified example, and fig. 17B is a right side view of the gear.

Fig. 18 is a schematic view comparing the convex portion having a sharp tip shown in fig. 17 with a convex portion having a rounded tip.

Fig. 19 is a diagram accompanied with an explanation of a second modified example of an internal gear according to an embodiment of the present invention, in which fig. 19A is a rear view of the internal gear as the second modified example, and fig. 19B is a right side view of the gear.

Fig. 20 is a diagram accompanied with an explanation of a third modified example of an internal gear according to an embodiment of the present invention, in which fig. 20A is a rear view of the internal gear as the third modified example, and fig. 20B is a right side view of the gear.

Fig. 21 is a diagram accompanying the explanation of a fourth modified example of an internal gear according to an embodiment of the present invention, in which fig. 21A is a rear view of the internal gear as the fourth modified example, and fig. 21B is a right side view of the gear.

Fig. 22 is a diagram accompanying the explanation of a fifth modified example of an internal gear according to an embodiment of the present invention, in which fig. 22A is a rear view of the internal gear as the fifth modified example, and fig. 22B is a right side view of the gear.

Fig. 23 is a diagram accompanying the explanation of a sixth modified example of an internal gear according to an embodiment of the present invention, in which fig. 23A is a rear view of the internal gear as the sixth modified example, and fig. 23B is a right side view of the gear.

Fig. 24 is a diagram accompanying the explanation of a seventh modified example of an internal gear according to an embodiment of the present invention, in which fig. 24A is a rear view of the internal gear as the seventh modified example, and fig. 24B is a right side view of the gear.

Fig. 25 is a diagram accompanying the explanation of an eighth modified example of an internal gear according to an embodiment of the present invention, in which fig. 25A is a rear view of the internal gear as the eighth modified example, and fig. 25B is a right side view of the gear.

Fig. 26 is a diagram accompanying the explanation of a ninth modified example of an internal gear according to an embodiment of the present invention, in which fig. 26A is a rear view of the internal gear as the ninth modified example, and fig. 26B is a right side view of the gear.

Fig. 27 is a diagram accompanying the description of a 10 th modified example of an internal gear according to an embodiment of the present invention, in which fig. 27A is a rear view of the internal gear as the 10 th modified example, and fig. 27B is a right side view of the gear.

Fig. 28 is a diagram accompanying the explanation of the 11 th modified example of the internal gear according to the embodiment of the present invention, in which fig. 28A is a rear view of the internal gear as the 11 th modified example, and fig. 28B is a right side view of the gear.

Fig. 29 is a diagram accompanying the description of the 12 th modified example of the internal gear according to the embodiment of the present invention, in which fig. 29A is a rear view of the internal gear as the 12 th modified example, and fig. 29B is a right side view of the gear.

Detailed Description

A separate structural unit for an internal gear and a housing, a planetary gear device, and an actuator according to ideal embodiments of the present invention will be described below with reference to the accompanying drawings. Note that, for ease of understanding the drawings, in each of the drawings, an orthogonal coordinate system is shown in which the X axis is parallel to the axial direction of the actuator 1 according to the embodiment according to the present invention, and the Y axis and the Z axis are perpendicular to the X axis.

(Structure of actuator 1)

As shown in fig. 1 and 2, the actuator 1 includes, for example, a motor 10 and a planetary gear device 20 connected to the motor 10.

The motor 10 has, for example, a motor main body 11 and a rotary shaft 12, as shown in fig. 3 and 4. The motor 10 rotates the rotary shaft 12 under the control of a control section (not shown) to drive the planetary gear device 20.

The planetary gear device 20 reduces the rotation input from the motor 10 shown in fig. 1 at a predetermined reduction ratio, and outputs the rotation to the output gear 86 a. The planetary gear device 20 includes, for example, a housing 50 having a first housing 30 and a second housing 40, and a planetary gear mechanism 60 accommodated in the housing 50, as shown in fig. 3 and 4.

The first housing 30 is a member for attaching the motor 10 to the planetary gear device 20, for example. Further, the first housing 30 is assembled with the second housing 40 to form an accommodating space S for accommodating the planetary gear mechanism 60, as shown in fig. 5. As shown in fig. 4, an opening 30a is formed at the center of the first housing 30, and the rotary shaft 12 of the motor 10 passes through the opening. The rotary shaft 12 passing through the opening 30a is fixed (connected) to a sun gear 71 of the planetary gear mechanism 60 as described below. The first housing 30 is formed by injection molding and is made of, for example, synthetic resin.

The second housing 40 is open on the side ("one side") connected to the first housing 30, for example, as shown in fig. 5 and 6, and the planetary gear mechanism 60 shown in fig. 4 can be accommodated in the second housing from the open portion. For example, as shown in fig. 4, the planetary gear mechanism 60 has a first planetary gear mechanism 70, a second planetary gear mechanism 80, and an output gear 86a arranged in the axial direction. The planetary gear mechanism 60 reduces (input) rotation generated by the motor 10 in two stages and outputs it from the output gear 86 a. For example, as shown in fig. 5, the second casing 40 has a first position 41 in which the first planetary gear mechanism 70 is accommodated, a second position 42 in which the second planetary gear mechanism 80 is accommodated, and a third position 43 in which the output gear 86a of the second planetary gear mechanism 80 protrudes outward.

For example, as shown in fig. 5 and 6, the first position 41 of the second housing 40 has a cylinder 44 and a stopper (second convex portion) 45 extending in the axial direction (from one side toward the other side in the axial direction). When divided in a cross section perpendicular to the axial direction, the stopper 45 has a chevron-shaped cross section in which the shape and size thereof are constant in the axial direction. The stopper 45 is formed in the range of a part of the first position 41 in the axial direction, but may alternatively be formed in the entire range thereof. For example, as shown in fig. 9, the stoppers 45 are provided so as to form a pair in the circumferential direction of the inner wall 44a of the cylinder 44. For example, the pairs of stoppers 45 are provided at six positions on the inner wall 44a of the cylinder 44 at equal intervals. For example, as shown in fig. 10, each stopper 45 has a cross-sectional shape having an upright portion 45a forming an arc gradually rising from the inner wall 44a of the cylinder 44, a rounded top portion 45c, and a connecting portion 45b for connecting the upright portion 45a and the top portion 45c at the time of bulging. Note that the shape and size of the cross section of the stopper 45 are constant in the axial direction. Thus, for example, as can be understood from fig. 6, the upright portion 45a, the connecting portion 45b, and the top portion 45c are curved surfaces that are not curved in a direction parallel to the axis. The movement restricting convex portions 75 of the internal gear 74 shown in fig. 9 and described later are interposed between the pair of stoppers 45 to restrict the movement of the internal gear 74 within the second housing 40.

For example, as shown in fig. 5 and 6, the second position 42 of the second housing 40 has a cylinder 46 and an internal tooth portion 47 formed on an inner wall of the cylinder 46. The internal tooth portions 47 are angled, for example, at an angle relative to the axial direction. That is, the second position 42 in which the internal tooth portion 47 is present is configured as, for example, a helical gear.

The third position 43 of the second housing 40 is formed, for example, as a cylinder, and has an opening 43a through which the output gear 86a of the planetary gear mechanism 60 passes, as shown in fig. 4. The torque output from the output gear 86a can thus be transmitted to the external mechanism. The second housing 40 is formed by injection molding and is made of, for example, synthetic resin.

In addition, for convenience in the present specification, in fig. 4 to 6, the side of the second housing 40 opened so as to be attached to the first housing 30 is referred to as "one side" (-X-direction side), and the side of the second housing 40 having the opening 43a of the third position 43 is referred to as "the other side" (+ X-direction side), which is the opposite side. However, the present invention is not limited thereto, and the side of the second case 40 having the opening 43a of the third position 43 may be noted and interpreted as one side, and the side of the second case 40 opened for attaching the first case 30 may be noted and interpreted as the other side.

For example, as shown in fig. 4, the planetary gear mechanism 60 is housed in the case 50, and reduces the rotation transmitted from the motor 10 and outputs it from the output gear 86 a. The planetary gear mechanism 60 has, for example, a first planetary gear mechanism 70 and a second planetary gear mechanism 80 arranged in the axial direction.

For example, as shown in fig. 7, the first planetary gear mechanism 70 includes: a sun gear 71; three (a plurality of) planetary gears 72 disposed around the periphery centered on the sun gear 71; a carrier 73 for rotatably supporting three (a plurality of) planetary gears 72; and an internal gear 74. Note that although only two planetary gears 72 are shown in the perspective view of fig. 7 for convenience, the other planetary gear 72 is provided at a position on the back surface, being blocked by the carrier 73.

The sun gear 71 is an external gear having a sun gear portion 71a formed on an outer peripheral surface thereof, and the rotary shaft 12 of the motor 10 shown in fig. 4 is fixed (connected) to the external gear. In this way, the sun gear 71 is rotated by the operation of the motor 10. The sun gear portion 71a has, for example, helical teeth cut at an angle with respect to the axis of the sun gear 71. That is, the sun gear 71 is, for example, a helical gear.

The planetary gear 72 is, for example, an external gear in which a planetary tooth portion 72a is formed on an outer peripheral surface thereof. The planetary gear portion 72a has, for example, helical teeth cut at an angle with respect to the axis of the planetary gear 72. That is, the planetary gear 72 is, for example, a helical gear. The three planetary gears 72 are arranged at equal intervals on the same circle centered on the axis of the first planetary gear mechanism 70. The sun gear 71 is positioned between the three planet gears 72, with the sun gear portion 71a meshing with a respective planet gear portion 72a of the three planet gears 72.

The carrier 73 is formed in, for example, a cylindrical shape in which three receiving openings 73a for receiving the planetary gears 72 are formed in an outer peripheral surface thereof. Each of the respective planet gears 72 is rotatably supported within the corresponding receiving opening 73a by an axially facing pin 76, as shown in fig. 3. The planetary gear 72 is attached in a state in which, for example, a part of the planetary tooth portion 72a protrudes from the outer peripheral surface of the carrier 73. Thus, the planet gear portions 72a can mesh with the internal gear portions 74a of the internal gear 74, as described below.

The internal tooth portions 74a are formed on the inner peripheral surface of the internal gear 74, as shown in fig. 3 and 7, for example. The internal gear portion 74a is, for example, a helical gear having helical teeth cut at an angle with respect to the axis of the internal gear 74. The tip rounding diameter of the internal gear 74 is larger than the diameter of the cylindrical holder 73. Thus, the carrier 73 holding the planetary gears 72 is accommodated in the interior of the internal gear 74. The planet gear portions 72a protruding from the outer peripheral surface of the carrier 73 mesh with the internal gear portions 74a of the internal gear 74.

Further, a movement restricting convex portion (first convex portion) 75 which enters into a gap between the pair of stoppers 45 formed on, for example, the inner wall 44a of the second housing 40 is formed on the outer peripheral surface of the internal gear 74, as shown in fig. 9. Movement restricting convex portions 75 corresponding to, for example, pairs of stoppers 45 formed in six positions are provided, similarly to the pairs of stoppers 45. The movement restricting convex portion 75 has a substantially triangular cross section when divided by a plane perpendicular to the axial direction. As shown in fig. 11, the movement restricting convex portion 75 has, for example, a straight inclined edge portion 75a rising from the outer peripheral surface 74b of the internal gear 74, and a rounded top portion 75b positioned at a position where the inclined edge portions 75a rising from both sides intersect. Note that, as shown in fig. 7, the cross-sectional shape and size of the movement restricting convex portion 75 are constant in the axial direction (have a constant extension from one side to the other side in the axial direction), and therefore the inclined edge portion 75a of the movement restricting convex portion 75 configures a planar region. Note that although the movement restricting convex portions 75 are formed over the entire width of the inner gear 74, they may alternatively be formed in only a part of the range of the inner gear. The internal gear 74 is made of, for example, synthetic resin. Note that, as described below, the internal gear 74 is formed of a synthetic resin having a hardness smaller than that of the synthetic resin forming the second housing 40 shown in fig. 9.

The internal gear 74 has a contact boss portion (contact portion) 742 that protrudes in the axial direction on an end surface 740 on the other side in the axial direction. The other side end surface 740 is an open end surface extending between the inner and outer peripheral surfaces on the other side and the portion in the axial direction. The contact protrusion part 742 contacts the second housing 40 in the axial direction. In the second housing 40, the surface contacted by the contact projecting portion 742 is a contact surface portion 411 that restricts the movement of the internal gear 74 toward the other side in the actual direction by the contact of the internal gear 74 with the end portion on the other side in the axial direction inside the second housing 40. The contact surface portion 411 is provided to face the other side end surface 740 in the internal gear. It is to be noted that the contact surface portion 411 is provided on the other side of the first position 41, but is also used as an end surface on one side of the second position 42 in the present invention. The internal gear 74 is in a state of being accommodated in the second housing 40 so as to contact the contact surface portion 411 of the second housing 40 in the axial direction through the contact convex portion 742.

The contact convex portion 742 protrudes toward the contact surface portion 411 side. In the present embodiment, the contact projecting portions 742 are provided in plurality on the end surface 740 in the circumferential direction. The number of the contact projection parts 742 provided may be any number as long as the configuration is a configuration in which the gear 74 makes stable contact with the contact surface part 411 in the second housing 40, for example, a configuration in which there is contact with the contact surface part 411 without axial inclination and with axial centering. At least three contact protrusion portions 742, which make point contact with the contact surface portion 411, are provided on the end surface 740. Further, the contact convex portions 742 may protrude with a plurality of thereof (with spaces therebetween) at equal intervals in the circumferential direction on the end face (opening end face) 740, or may protrude with a plurality of thereof (with spaces therebetween) at unequal intervals in the circumferential direction on the end face 740. Further, the number of the contact protrusion parts 742 is not particularly limited, and at least one thereof should be provided. Further, the contact projection 742 may be configured such that the area of the cross section perpendicular to the axial direction is smaller the farther from the end surface 740, which is an open end surface on the other side. Further, the contact projecting portion 742 may be provided in the gear 74 in the same manner as the end surface 740, on the opening end surface on the side to which the first housing 30 is attached. This can suppress the transmission of vibration to the first housing 30, or the transmission of vibration from the first housing 30.

The contact convex portion 742 contacts the second housing 40 on the other side (in the axial direction) of the internal gear 74 to become a vibration path to the second housing 40, thereby serving for vibration generated from the internal gear 74 side. The contact projecting portion 742 has a smaller area for a cross section perpendicular to the axial direction of the portion of the internal gear 74 that contacts the second housing 40 in the axial direction than a cross section when the end surface 740 will contact the second housing 40 in the axial direction.

The contact projection portion 742 may be configured such that the area of a cross section perpendicular to the axial direction becomes gradually smaller toward the other side in the axial direction (i.e., toward the contact surface portion 411). The contact convex portion 742 reduces vibration generated in the internal gear 74 (i.e., vibration driven by the first planetary gear mechanism 70) to the second housing 40.

In the present embodiment, the contact protrusion part 742 is formed in a hemispherical shape, as shown in fig. 3 and 7, and thus contacts the contact surface part 411 of the second housing 40 on the other side in the axial direction (with point contact). This more effectively suppresses transmission of vibration from the internal gear 74 side to the second housing 40 in the axial direction.

Although the contact convex portion 742 of the present embodiment has a structure formed in a hemispherical shape, it may be configured in any shape as long as it reduces an area of propagation of vibration to the other end side in the axial direction. For example, the contact projection portion 742 may be formed in a tapered body with a tip portion on the contact surface portion 411 side being a top portion. The internal gears equipped with the contact convex portions as described above are described as modified examples 1 to 11 of the internal gears used in the separate structural unit, the planetary gear device, and the actuator according to the present invention.

As shown in fig. 9, the second housing 40 and the internal gear 74 are physically separated, and a gap is formed therebetween when the actuator 1 is not operated. Therefore, the internal gear 74 is in a floating state within the second housing 40, thereby allowing rotation about the axial direction, and allowing movement in a direction perpendicular to the axial direction within the second housing 40 by an amount equivalent to the clearance provided between the internal gear 74 and the second housing 40. In addition, by the stopper 45 formed on the internal gear 74 contacting the movement restricting convex portion 75, further movement of the internal gear 74 is prevented.

The second planetary gear mechanism 80 (which is another planetary gear mechanism) includes, for example, a sun gear 81, three planetary gears 82, a carrier 83 that rotatably supports the three planetary gears 82, and an output shaft 86, as shown in fig. 8. Note that although only two planetary gears 82 are shown in the perspective view of fig. 8 for convenience, the other planetary gear 82 is provided at a position on the back surface, being blocked by the carrier 83.

The sun gear 81 is an external gear on which a sun gear portion 81a is formed, for example, on an outer peripheral surface, and is fixed (connected) to the carrier 73 of the first planetary gear mechanism 70 in a state in which the axes are aligned together, as shown in fig. 7. Thus, as the carrier 73 of the first planetary gear mechanism 70 rotates, the sun gear 81 will rotate (linked for synchronization) the same as the rotation of the carrier 73 of the first planetary gear mechanism 70. That is, as the carrier 73 of the first planetary gear mechanism 70 rotates, the sun gear 81 rotates at the same rotational speed as the carrier 73 of the first planetary gear mechanism 70 because its rotational direction is the same as the carrier 73 of the first planetary gear mechanism 70. The sun gear portion 81a has, for example, helical teeth cut at an angle with respect to the axis of the sun gear 81. That is, the sun gear 81 is, for example, a helical gear.

The planetary gear 82 is, for example, an external gear in which a planetary tooth portion 82a is formed on an outer peripheral surface thereof. The planetary gear portion 82a has, for example, helical teeth cut at an angle with respect to the axis of the planetary gear 82. That is, the planetary gear 82 is, for example, a helical gear. For example, the three planetary gears 82 are provided at equal intervals on the same circle centered on the axis of the second planetary gear mechanism 80. The sun gear 81 is positioned between the three planetary gears 82, with the sun gear portion 81a meshing with the respective planetary gear portions 82a of the three planetary gears 82. In addition, the planetary gears 82 mesh with the internal tooth portions 47 formed on the second housing 40, as shown in fig. 5 and 6.

The carrier 83 has, for example, a gear holding portion 84 for holding the planetary gears 82 and an output shaft holding portion 85 for holding the output shaft 86. The gear holding portion 84 is formed in, for example, a cylindrical shape in which three receiving openings 84a for receiving the planetary gears 82 are formed in an outer peripheral surface of the carrier. Each of the individual planet gears 82 is rotatably attached within a respective receiving opening 84a by an axially facing pin 87, as shown in fig. 3. The planetary gear 82 is attached in a state in which a part of the planetary tooth portion 82a protrudes from the outer peripheral surface of the carrier 83. This makes it possible to mesh the planetary gear portions 82a with the internal gear portions 47 formed on the second housing 40. Further, as shown in fig. 8, the output shaft holding portion 85 is formed as a cylindrical body having a diameter smaller than that of the gear holding portion 84, and a fitting hole 85a for holding the output shaft 86 is formed in a central portion of the output shaft holding portion 85.

The output shaft 86 is held on the carrier 83, for example, and rotates together with the carrier 83. The output shaft 86 has an output gear 86a having knurled-shaped teeth on the shaft. That is, the output shaft 86 configures a gear having, for example, teeth in a knurled shape.

(operation of actuator 1)

An example of the operation of the actuator 1 will be explained below. First, when the motor 10 shown in fig. 4 is operated, the rotation shaft 12 is rotated in the first direction or the second direction. The following description will be directed to the case where the rotary shaft 12 rotates in the first direction.

Note that, with respect to the rotational direction of each of the members, the first direction is a clockwise direction when all the members are viewed from the direction indicated by the arrow AII shown in fig. 1. On the other hand, with respect to the rotational direction of each of the members, the second direction is a counterclockwise direction when all the members are viewed from the direction indicated by the arrow AII shown in fig. 2.

When the rotary shaft 12 rotates in the first direction, the sun gear 71 (shown in fig. 3 and 7) rotates in the first direction with the rotation of the rotary shaft 12. As the sun gear 71 rotates in the first direction, the three planetary gears 72 that mesh with the sun gear 71 each rotate in the second direction. Further, since the planetary gears 72 are meshed with the internal gear 74, they are rotated (revolved) in the first direction around the axis of the first planetary gear mechanism 70 by the rotation in the second direction. With the rotation (revolution) of the planetary gear 72, the carrier 73 rotates in the first direction centering on its own axis.

Thus, when the carrier 73 is rotated in the first direction, the sun gear 81 (shown in fig. 3 and 8) fixed by the carrier 73 will be rotated in the first direction. As the sun gear 81 rotates in the first direction, the three planetary gears 82 that mesh with the sun gear 81 each rotate in the second direction. Further, since the planet gears 82 are meshed with the internal tooth portions 47, as shown in fig. 5 and 6, they are rotated (revolved) in the first direction around the axis of the second planetary gear mechanism 80 by the rotation in the second direction. With the rotation (revolution) of the planetary gear 82 in the first direction, the carrier 83 rotates in the first direction centering on its own axis. In view of this, the rotation of the carrier 83 is transmitted to the output shaft 86 held on the carrier 83.

Although the above description is of the case where the rotary shaft 12 is rotated in the first direction, the description of the operation of the actuator 1 will be the same if the rotary shaft 12 is rotated in the second direction, where only the rotational direction of each of the gears is reversed.

As described above, the second housing 40 and the internal gear 74 are physically separated. In addition, when the actuator 1 is not operated, a gap is formed between the second housing 40 and the internal gear 74. In view of this, when the actuator 1 is operated, the internal gear 74 may rotate about the axis of the second housing 40, or move in a direction perpendicular to the axis by an amount equivalent to the clearance provided. For example, when the internal gear 74 is rotated in the first direction (clockwise) from the state shown in fig. 9, each of the plurality of movement limiting convex portions 75 formed on the internal gear 74 will soon come into line contact with the corresponding stopper 45 formed on the second housing 40, as shown in fig. 12. Thus, the internal gear 74 will not be able to rotate any further in the clockwise direction. Because the stoppers 45 are formed in pairs, even if the internal gear 74 rotates in the second direction (counterclockwise direction), the rotation of the internal gear 74 about the axis will be restricted by the same line contact.

Further, the internal gear 74 moves in a direction perpendicular to the axis from the state shown in fig. 9, for example, moves upward in the drawing. In view of this, as shown in fig. 13, the movement restricting convex portion 75 formed on the internal gear 74 at the upper portion in the figure makes line contact with the stopper 45 formed on the second housing 40. Thus, the internal gear 74 will not be able to move further in the upward direction, and movement in the direction perpendicular to the axis will be limited. Further, in this case, the top portion 75b of the internal gear 74 (more specifically, the top portion 75b of the movement restricting convex portion 75) will not contact the second housing 40 (or more specifically, the inner wall 44a of the cylinder 44). Note that, in the case where the internal gear 74 moves upward, the restriction of the movement of the internal gear 74 in the direction perpendicular to the axis is not limited. Since the six pairs of the movement restricting convex portions 75 and the stoppers 45 are arranged at equal intervals in the circumferential direction, they can restrict the movement of the internal gear 74 in various directions (for example, the vertical direction, the lateral direction, and the diagonal direction in fig. 9).

(Effect)

In view of the above-described embodiment, even if the internal gear 74 is to be moved during the operation of the actuator 1 in a structural unit in which the internal gear 74 and the second housing 40 are separated, the stopper 45 and the movement restricting convex portion 75 are to make line contact, thereby restricting the movement of the internal gear 74. Fig. 12 shows a line contact state between the internal gear 74 and the second housing 40 by rotation of the internal gear 74 about the axis. In this case, the stopper 45 makes contact with the movement restricting convex portion 75 in all six positions, and the form of the contact is the same for all the positions. Thus, a single contact location where the contact is at the top in the figure will be described with reference to the enlarged view in fig. 12. As shown, the contact position between the connecting portion 45b (shown by a raised convex curve) of the stopper 45 and the inclined edge portion 75a (shown by a straight line) of the movement restricting convex portion 75 may be depicted as a contact point P1. I.e. the contact will be within an extremely limited range. Note that the cross section of the second housing 40 and the cross section of the internal gear 74 have constant shapes and sizes in the axial direction. Therefore, the contact between the connecting portion 45b and the inclined edge portion 75a will be the contact between the convex curved surface having no curvature in the direction parallel to the axis and the plane parallel to the axis. Thus, the contact between the internal gear 74 and the second housing 40 will be a line contact along an axial direction parallel to the X-axis, as with the contact region 90 shown in fig. 14.

Further, fig. 13 shows a state of contact between the second housing 40 and the internal gear 74 by movement of the internal gear 74 in a direction perpendicular to the axis (e.g., movement in an upward direction in the drawing). As shown in fig. 13, the positions of contact between the second housing 40 and the internal gear 74 are four positions indicated by contact points P2 to P5. As shown in the enlarged view in fig. 13, the contact points P2 and P3 are the contact positions between the connecting portion 45b (shown by a raised convex curve) of the stopper 45 and the inclined edge portion 75a (shown by a straight line) of the movement restricting convex portion 75. In the same manner as described above, such a contact position is a line contact between the two, which is assumed to be a contact having a convex curved surface with no curvature in a direction parallel to the axis and a plane parallel to the axis. Further, the contacts between the stopper 45 and the movement restricting convex portion 75 at the contact points P4 and P5 will also be line contacts because they are contacts between convex curved surfaces and flat surfaces.

In this way, by providing the pair of stoppers 45 (having convex curved surfaces) having a chevron shape, and being configured to facilitate the insertion of the triangular movement-limiting convex portion 75 (having a flat inclined surface) therebetween, the contact between the internal gear 74 and the second housing 40 can be made a line contact even when the internal gear 74 has rotated about the axis, and even when the internal gear has moved in the direction perpendicular to the axis. Since the contact area between the internal gear 74 and the second housing 40 is small (line contact is made in this manner), the vibration transmitted from the internal gear 74 to the second housing 40 during operation will be reduced. Thereby, the vibration of the second housing 40 generated by being transmitted from the first planetary gear mechanism 70 is suppressed, thereby making it possible to suppress the noise generated from the planetary gear device 20 with the vibration caused by the first planetary gear mechanism 70.

Note that "line contact" described in this specification is a contact state in which the contact portion forms a line, and indicates not only a contact state to be shown by a single point or a plurality of points as a contact point in each individual cross section, but, as shown in fig. 14, a contact state including a form in which the width W is considered to be sufficiently small when compared with the length L in the contact area 90. Further, "line contact" used in the present specification also includes a contact state in which the contact is discontinuous (sporadic contact) so that the width W in the contact area 90 will form a line when an imaginary line is drawn in the axial direction. Further, "line contact" used in the present specification also includes a contact state in which the width W in the contact region 90 forms a line describing an angle rather than a line in the axial direction. Further, "line contact" used in the present specification also includes a contact discontinuity (sporadic contact) therein, so that when an imaginary line is drawn as an angled line instead of in the axial direction, the width W in the contact region 90 will form a line contact state.

Although in the above-described embodiments, the description has described the form in which the first convex portion and the second convex portion are brought into line contact, the present invention is not limited thereto, but the contact method may be appropriately selected depending on the form, and may be a form in which there is point contact or a form in which there is surface contact between the first convex portion and the second convex portion.

Further, as shown in fig. 11, the cross section of the movement restricting convex portion 75 taken by a plane perpendicular to the axis is triangular to configure an outward facing top portion 75b (which is narrow at the top end) to allow the internal gear 74 to be easily removed from the mold during injection molding. This improves yield.

Further, as shown in fig. 15, in a cross section taken by a plane perpendicular to the axial direction, the movement restricting convex portion 75 is formed with straight inclined edge portions 75a on both sides. Further, fig. 15 shows a movement restricting convex portion 100 as a reference example of the movement restricting convex portion 75, and the shape of the movement restricting convex portion 100 is shown by a two-dot chain line in which both sides are swollen. Comparing the two, the cross-sectional area of the movement restricting convex portion 75 is reduced by an amount equivalent to the area of the region indicated by the hatching compared with the cross-sectional area of the movement restricting convex portion 100. In view of this, the present embodiment can reduce the load on the motor 10 by reducing the weight of the internal gear 74, and also reduce the manufacturing cost. Further, since the weight of the internal gear 74 to be operated is reduced, the present invention can reduce (suppress) the impact when the internal gear 74 contacts the second housing 40, thereby making it possible to also reduce (suppress) the vibration of the second housing.

Further, the internal gear 74 is formed of a synthetic resin having a hardness smaller than that of the synthetic resin used to form the second housing 40. From the viewpoint of mechanical strength, wear resistance, thermal durability, and the like, it is preferable that the synthetic resin for forming the internal gear 74 and the second housing 40 use engineering plastics or super engineering plastics. These synthetic resins may be, for example, ultra-polymer polyethylene (UHPE), polyphenylene sulfide (PPS), Polyarylate (PAR), Polyoxymethylene (POM), Polyamide (PA), Polycarbonate (PC), polybutylene terephthalate (PBT), Polyethersulfone (PES), Polyetheretherketone (PEEK), and the like.

The synthetic resin used to form the internal gear 74 and the second housing 40 may be the same material or may be different materials. They may be appropriately selected within the range that produces the effects of the present invention.

Among the above synthetic resins, the synthetic resin, which is relatively soft and suitable for forming the internal gear 74, preferably uses, for example, ultra-polymer polyethylene (UHPE), polyphenylene sulfide (PPS), Polyarylate (PAR), Polyoxymethylene (POM), or Polyamide (PA). Further, it is preferable that a relatively hard synthetic resin suitable for forming the second housing 40 uses, for example, Polycarbonate (PC), polybutylene terephthalate (PBT), polyether sulfone (PES), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), Polyoxymethylene (POM), or Polyamide (PA). Further, when a synthetic resin material having the same main component is used for the synthetic resin material used for forming the internal gear 74 and the second housing 40, it is preferable that the synthetic resin used for forming the second housing 40 be harder by changing, for example, the density of the synthetic resin.

By forming the internal gear 74 from a synthetic resin having a hardness smaller than that of the second housing 40, as such, the impact when the internal gear 74 contacts the second housing 40 can be improved, so that the vibration generated in the second housing 40 can be reduced (suppressed). In this way, the present invention can reduce (suppress) noise caused by vibration of the second casing 40, and can further reduce (suppress) noise when the internal gear 74 collides with the second casing 40. Therefore, it is possible to suppress noise generated from the planetary gear device 20 along with vibration caused by the first planetary gear mechanism 70.

Further, in the present embodiment, the structure in which the housing and the internal gear are separated is applied only to the first planetary gear mechanism that rotates at a high speed, and is not applied to the second-stage planetary gear mechanism that rotates at a low speed. That is, in the present embodiment, a structure in which the internal gear is floated is used in a mechanism that rotates at high speed and tends to generate large vibration and noise, and a case structure that forms internal teeth is used in a mechanism that rotates at low speed, in which vibration and noise tend to be relatively small. In this way, the present embodiment not only suppresses vibration and noise of the planetary gear device caused by the planetary gear mechanism, but also can prevent the number of components in the planetary gear device from increasing more than necessary, and prevent the assembly operation and the assembly cost from increasing. Therefore, the manufacturing cost of the planetary gear device can be reduced. Thus, depending on the case, two mechanisms having different structures may be employed, depending on the rotation form of the planetary gear mechanism, wherein the two mechanisms may be used in parallel.

(modified example)

The present invention is not limited to the above-described embodiments, but can be variously modified and applied. In the above embodiment, the pair of stoppers 45 is provided in the second housing 40, and the movement restricting convex portion 75 interposed between the pair of stoppers 45 is provided on the internal gear 74. However, the present invention is not limited thereto, but the positions in which the pair of stoppers 45 and the movement restricting convex portion 75 are provided may be switched such that the movement restricting convex portion 75 is provided on the inner peripheral surface of the second housing 40 and the pair of stoppers 45 is provided on the outer peripheral surface of the inner gear 74.

Although the cross-sections of the stopper 45 pairs are herringbone shapes and the cross-sections of the movement restricting convex portions 75 are triangular, these cross-sectional shapes may be changed such that the cross-sections of the stopper pairs are triangular and the cross-sections of the movement restricting convex portions interposed between the stoppers are herringbone shapes.

Further, there is no particular limitation on the number of positions at which the pair of stoppers 45 and the corresponding movement restricting convex portions 75 are provided, and the number may be a larger number of positions or a smaller number of positions than the six positions given in the above-described embodiment.

Further, although the convex curved surfaces of the pair of stoppers 45 are caused to contact the flat surfaces of the movement restricting convex portions 75 to cause line contact therebetween, line contact may be achieved by causing contact of other shapes. Next, another embodiment of achieving the line contact will be explained with reference to fig. 16. A point different from the structure shown in the enlarged view of fig. 9 is that the cross section of the movement restricting convex portion (first convex portion) 175 is not a triangular cross section but a rounded chevron shape. Note that the structure of the second housing 40 is the same as that shown in the enlarged view in fig. 9. In fig. 16, when the actuator is not operated, the internal gear 174 is indicated by a solid line. Further, the internal gear 174 shown by the two-dot chain line is in a state where it has been moved upward by the operation of the actuator to contact the second housing 40. As shown in fig. 16, the contact between the pair of stoppers 45 and the movement restricting convex portions 175 is the contact between convex curved surfaces, and therefore, the line contact will be made at the contact points P6 and P7 between the pair of stoppers 45 and the movement restricting convex portions 175. Thus, in the present embodiment, line contact is achieved by causing the bulging convex curved surfaces to contact each other.

Further, there is no limitation in that the line contact may be achieved by the second housing 40 having a partially concave part of large curvature, the internal gear 74 having a convex curved surface of smaller curvature, wherein a concave curved surface having high curvature contacts a convex curved surface of swelling. The actual structure used to achieve the line contact is arbitrary.

Note that, in another example for achieving the above-described line contact, the configuration of the internal gear at the position where the line contact is made may be exchanged with the configuration of the second housing.

Further, although the actuator 1 is provided with a two-stage planetary gear mechanism composed of the first planetary gear mechanism 70 and the second planetary gear mechanism 80, the number of stages may be arbitrarily set as a speed reduction mechanism for reducing the rotation of the motor 10. For example, the reduction ratio may be increased by providing a three-stage or more planetary gear mechanism, or the structure may include only a single-stage planetary gear mechanism.

Further, in the above-described embodiment, a configuration is used in which a structure in which the housing and the internal gear are separated is applied only to the first planetary gear mechanism 70 which is a first-stage mechanism that rotates at a high speed, and the housing having the internal teeth formed on the inner peripheral surface thereof is used in the second planetary gear mechanism 80 which is a second-stage mechanism that rotates at a low speed. However, a structure in which the housing and the internal gear are separated may also be used for the second planetary gear mechanism 80 as the second-stage mechanism to achieve reduction in vibration and noise.

Further, although in the above-described embodiment, the description is directed to the case where the reduction gear is used to reduce the rotation of the motor 10 and output it from the output gear 86a, the present application is not limited. For example, the member provided with the output shaft 86 shown in fig. 8 may be used as an input side and connected to the rotating shaft of the motor, and the member provided with the sun gear 71 shown in fig. 7 may be used as an output side and connected to the output shaft. This will increase and output the rotation of the motor to serve as a speed increasing mechanism. In this case, due to the high-speed operation of the first planetary gear mechanism 70 shown in fig. 7, a structure in which the internal gear and the housing are separated is also preferably employed. Further, since the rotation of the motor is directly transmitted to the second planetary gear mechanism 80 shown in fig. 8, it is preferable to adopt a structure in which the internal gear and the housing are separated as needed. Furthermore, the invention is also applicable to industrial equipment such as robots and machine tools, and to playground equipment such as so-called "spinning cups".

When the present invention is used in various applications, when the planetary gear mechanism is provided in three or more stages, separate structural units for the internal gear and the housing are applied to the planetary gear mechanism that operates at the highest speed. This can effectively reduce the generated vibration and noise. Further, since the planetary gear mechanism operating at the lowest speed generates little vibration and noise, a structure equipped with a housing in which internal teeth are formed on an inner peripheral surface is applied. This eliminates the need for an unnecessary separate structure for the internal gear and the housing, thereby making it possible to avoid an increase in the number of parts and an increase in assembly operation and assembly cost, and further making it possible to suppress production cost.

Further, although in the above-described embodiment, the description is directed to the case where each of the gears for transmitting power from the motor 10 to the output shaft 86 is a helical gear, other gears may be used instead. For example, spur gears may be used. Although the spur gear tends to produce a larger clearance at the position where the teeth mesh when compared with the case where the helical gear is used, the structure of the present invention can be used even in such a case to reduce (suppress) the vibration and noise of the planetary gear device.

(modified embodiment of internal Gear)

Fig. 17 is a diagram accompanying the description of a first modified example of the internal gear 74 according to the embodiment of the present invention, in which fig. 17A is a rear view of the internal gear 74A as the first modified example, and fig. 17B is a right side view of the internal gear 74A. As shown in fig. 17A and 17B, the internal gear 74A differs only in the shape of the contact convex portion 742A when compared with the internal gear 74.

The contact protrusion portion 742A is formed in a tetragonal conical shape which protrudes to the contact surface portion 411 side in an end surface (opening end surface) 740A of one side of the internal gear 74A contacting the contact surface portion 411 (the other side in the axial direction) of the second housing 40, and has a top of a tip portion on the contact surface portion 411 side. As shown in fig. 18A, the contact projection 742A is shaped to have a point such that the tip that contacts the contact surface portion 411 (i.e., the top of 742A) is pointed. In this way, as shown in fig. 18B, when compared with the contact convex portion 742 in which the tip of the contact convex portion 742A is rounded, the area of contact with the contact surface can be reduced even if the contact convex portion is deformed. In this way, the contact boss portion 742A can transmit vibration occurring on the side of the internal gear 74A (i.e., on one side in the axial direction), in a state where the vibration is more suppressed, when transmitted to the other side in the axial direction when compared with the case of the contact boss portion 742.

Fig. 19 is a diagram accompanied with an explanation of a second modified example of the internal gear 74 according to the embodiment of the present invention, in which fig. 19A is a rear view of an internal gear 74B as the second modified example, and fig. 19B is a right side view of the internal gear 74B. In the internal gear 74B, the contact convex portion 742B is different in shape when compared with the internal gear 74, wherein the contact convex portion 742B is formed in a triangular cone shape which protrudes to the contact surface portion 411 side in an end surface (opening end surface) 740B of one side of the internal gear 74B contacting the contact surface portion 411 (the other side in the axial direction) of the second housing 40 and has a top portion of a tip portion on the contact surface portion 411 side. This can produce a similar effect in operation as in modified example 1.

Fig. 20 is a diagram accompanied with an explanation of a third modified example of the internal gear 74 according to the embodiment of the present invention, in which fig. 20A is a rear view of an internal gear 74C as the third modified example, and fig. 20B is a right side view of the internal gear 74C. When compared with the internal gear 74, the internal gear 74C differs only in the shape of the contact convex portion 742C. The contact boss portion 742C is formed in a conical shape that protrudes to the contact surface portion 411 side in an end surface (opening end surface) 740C on one side of the internal gear 74C that contacts the contact surface portion 411 (the other side in the axial direction) of the second housing 40, and has the top of the tip portion on the contact surface portion 411 side. This can produce a similar effect in operation as in modified example 1.

Fig. 21 is a diagram accompanying the description of a fourth modified example of the internal gear 4 according to the embodiment of the present invention, in which fig. 21A is a rear view of an internal gear 74D as the fourth modified example, and fig. 21B is a right side view of the internal gear 74D. When compared with the internal gear 74, the internal gear 74D differs only in the shape of the contact convex portion 742D.

The contact projecting portion 742D is formed in a rod-like body that projects from an end surface (opening end surface) 740D on one side of the internal gear 74D that contacts the contact surface portion 411 (the other side in the axial direction) of the second housing 40 to the contact surface portion 411 side, and in which the tip of 742D is rounded in the shape of a spherical surface. Specifically, the contact protrusion portion 742D has a rod-like extension portion and a hemispherical surface portion provided on a tip of the extension portion. In this case, the tip has a hemispherical surface shape, and thus makes point contact with the contact surface 411 portion. This can suppress transmission of vibration from the internal gear 74D side to the second housing 40 even further.

Fig. 22 is a diagram accompanying the description of a fifth modified example of the internal gear 74 according to the embodiment of the present invention, in which fig. 22A is a rear view of an internal gear 74E as the fifth modified example, and fig. 22B is a right side view of the internal gear 74E. When compared with the internal gear 74, the internal gear 74E differs only in the shape of the contact convex portion 742E. A contact convex portion 742E is formed in an end surface (opening end surface) 740E of one side of the internal gear 74E that contacts the contact surface portion 411 (the other side in the axial direction) of the second housing 40 so as to protrude to the contact surface portion 411 side, and has a "+" shape when viewed from the back. The tip portion of the contact protrusion 742E is formed in a sharp shape and thus makes point contact with the contact surface portion 411.

When compared with the contact convex portions 742A to 742C having a pyramid or cone shape, and when compared with the contact convex portion 742D having a rod shape, the area of the contact convex portion 742E in a cross section perpendicular to the axial direction (i.e., the area for propagating vibration in the axial direction) is small. This can even further suppress the transmission of vibration from one side to the other side in the axial direction.

Fig. 23 is a diagram accompanying the description of a sixth modified example of the internal gear 74 according to the embodiment of the present invention, in which fig. 23A is a rear view of an internal gear 74F as the sixth modified example, and fig. 22B is a right side view of the internal gear 74F. The internal gear 74F shown in fig. 23 differs only in the shape of the contact convex portion 742F when compared with the internal gear 74.

A contact convex portion 742F is provided in an end surface (opening end surface) 740F of one side of the internal gear 74F that contacts the contact surface portion 411 (the other side in the axial direction) of the second housing 40 so as to protrude to the contact surface portion 411 side, and a shape of a cross section perpendicular to the axial direction therein forms "+", that is, a plus sign. The outer shape of the contact convex portion 742F is curved so as to protrude toward the tip end, making point contact with the contact surface portion 411 at the curved tip end portion.

When compared with the contact convex portions 742A to 742C that are pyramids or tapered bodies, and when compared with the contact convex portion 742D having a rod shape, the area of the contact convex portion 742F in a cross section perpendicular to the axial direction (i.e., the area for propagating vibration in the axial direction) is small. This can even further suppress the transmission of vibration from one side to the other side in the axial direction.

Fig. 24 is a diagram accompanying the description of a seventh modified example of the internal gear 74 according to the embodiment of the present invention, in which fig. 24A is a rear view of an internal gear 74G as the seventh modified example, and fig. 24B is a right side view of the internal gear 74G. When compared with the internal gear 74, the internal gear 74G differs only in the shape of the contact convex portion 742G. A contact projection portion 742G is formed in an end surface (opening end surface) 740G of one side of the internal gear 74G that contacts the contact surface portion 411 (the other side in the axial direction) of the second housing 40 so as to project to the contact surface portion 411 side.

The contact convex portion 742G is an arch-shaped body that protrudes to the other side and is bent such that the center of the tip face is the top. That is, the tip portion of the contact protrusion portion 742g is formed in the shape of a spherical surface. The contact projecting portions 742G are provided in parallel with each other on the end surface 740G with a prescribed spacing therebetween in the circumferential direction.

When compared with the contact convex portions 742A to 742C having a pyramid or cone shape, and when compared with the contact convex portion 742D having a rod shape, the area of the contact convex portion 742G in a cross section perpendicular to the axial direction (i.e., the area for propagating vibration in the axial direction) is small. This can even further suppress the transmission of vibration from one side to the other side in the axial direction.

Fig. 25 is a diagram accompanying the description of an eighth modified example of the internal gear 8 according to the embodiment of the present invention, in which fig. 25A is a rear view of an internal gear 74H as an eighth modified example, and fig. 24B is a right side view of the internal gear 74H. In the internal gear 74H, the direction of the contact convex portion 742G in the structure of the internal gear 74G is changed.

Specifically, the contact convex portion 742H of the internal gear 74H has the same shape as the contact convex portion 742G so as to protrude to the contact surface portion 411 at an end surface (opening end surface) 740H of one side (the other side in the axial direction) of the internal gear 74H contacting the contact surface portion 411 of the second housing 40.

The contact protrusion portions 742H are dome-shaped portions that protrude to the other side and are provided at regular intervals in the circumferential direction on the end surface 740H, with respective flat portions (e.g., the back surface) provided to face the axis of the second housing 40. This can suppress transmission of vibration from the internal gear 74H to the second housing 40 side even further.

Further, in the contact convex portion 742H, each flat portion in the end surface 740H (and specifically, the inner surface 7421 on the axis line side) is in a state of being arranged in the circumferential direction. The internal gear 74H is provided to effect a floating movement in the circumferential direction within the second housing 40, wherein the inside of the second housing 40 is coated with a lubricant (such as grease) on a portion that slides with the internal gear 74H. In the internal gear 74H inside the second housing 40, when coated with the lubricant, the lubricant will tend to remain on the inner surface 7421 in the circumferential direction even when the internal gear 74H moves in the circumferential direction, causing the internal gear 74H to maintain its floating state well inside the second housing 40.

Fig. 26 is a diagram accompanying the explanation of a ninth modified example of the internal gear 9 according to the embodiment of the present invention, in which fig. 26A is a rear view of an internal gear 74I as the ninth modified example, and fig. 26B is a right side view of the internal gear 74I. In the internal gear 74I, the direction of the contact convex portion 742G in the structure of the internal gear 74G is changed.

Specifically, the contact convex portion 742I of the internal gear 74I has the same shape as the contact convex portion 742G so as to protrude to the contact surface portion 411 at an end surface (opening end surface) 740I of one side (the other side in the axial direction) of the internal gear 74I contacting the contact surface portion 411 of the second housing 40.

The contact protrusion portions 742I are dome-shaped portions that protrude to the other side and are provided at regular intervals in the circumferential direction on the end surface 740I, with corresponding flat portions (e.g., back surface) provided in a radial shape in the radial direction of the second housing 40. This can suppress transmission of vibration from the internal gear 74I to the second housing 40 side even further.

Although the above-described contact

convex portions

742 and 742A to 742I are each provided in six at a time with equal spacing therebetween in the circumferential direction on the respective end surfaces (opening end surfaces) 740 and 740A to 740I in each of the embodiment and the modified examples of examples 1 to 8, any number thereof may be provided. For example, as shown in the internal gear 74J depicted with respect to fig. 27, three contact convex portions 742J may be provided to protrude on an end surface (opening end surface) 740J on one side (the other side in the axial direction) contacting the contact surface portion 411 of the second housing 40 with a space therebetween in the circumferential direction. The contact protrusion portion 742J is not limited to a structure in the same shape as the contact protrusion portion 742J shown in fig. 27, but may be provided in the same shape as any one of the contact protrusion portions 742A to 742I.

As described for the internal gear 74J, the smaller the contact boss portion 742J provided on the end surface 740J, the smaller the propagation path of the vibration to the contact surface portion 411, so that the transmission of the vibration from the internal gear 74J side to the second housing 40 can be suppressed. Further, although the contact

convex portions

742 and 742A to 742J in the

internal gears

74 and 74A to 74J are each configured to be arranged with an equal interval therebetween in the circumferential direction on the respective end surfaces 740 and 740A to 740J, there is no limitation thereto.

In the internal gear 74K, as an 11 th modified example of the internal gear 74 shown in fig. 28, the contact boss portions 742K protrude to the other side with unequal intervals therebetween in the circumferential direction on the end surface (opening end surface) 740K. Although the contact convex portion 742K is shaped like a hemisphere (the same as the contact convex portion 740) in the internal gear 74K in the 11 th modified example, there is no limitation thereto, the shape thereof may be the same as any one of the contact convex portions 742A to 742I of the internal gears 74A to 74I.

When compared with the internal gear 74, the internal gear 74L is provided with a contact boss portion 742L on an end surface 740L on the other side and an end surface on the other side (opening end surface) 741L opposite to the end surface 740L, as shown in fig. 29 as a 12 th modified example of the internal gear 74. The contact projecting portions 742L are provided on both end faces 740L and 741L with a plurality of projections thereof with a prescribed spacing therebetween in the circumferential direction (in the present embodiment, they are equally spaced). That is, the internal gear 74L is provided with a contact convex portion (contact portion on one side) that protrudes on an end surface (opening end surface) 741L on one side in the same manner as the contact convex portion 742L.

The internal gear 74L makes point contact with the contact surface 411 portion of the second housing 40 through the contact convex portion 742L on the end surface 740L on the other side, and makes point contact with the first housing 30 through the contact convex portion 742L on the end surface 741L on the one side.

Thus, in an actuator in which the internal gear 74L is also connected to the motor side by point contact, this can suppress transmission of vibration to the housing and the motor. Note that such a configuration in which contact convex portions are provided on both open end surfaces that are separated in the axial direction of the internal gear 74 may be applied to any of the internal gears 74A to 74K of the various modified examples 1 to 11, and effects similar to those of the internal gear 74L may be produced in operation in addition to the various effects described above.

With the

internal gears

74, 74A to 74C, and 74E to 74L shown in this embodiment and modified examples 1 to 12, the contact

convex portions

742, 742A to 742C, and 742E to 742L are formed such that the areas of the cross sections perpendicular to the axial direction will become smaller toward the protruding direction. That is, in addition to the

contact boss portions

742, 742A to 742C, and 742E to 742L being configured such that the areas of the cross sections perpendicular to the axial direction will become smaller as further away from the end surfaces (opening end surfaces) 740, 740A to 740C, and 740E to 740L on the other side, the

internal gears

74, 74A to 74C, and 74E to 74L are held within the first and

second housings

30 and 40 in a state in which the respective

contact boss portions

742, 742A to 742C, and 742E to 742L make point contact with the contact surface portion 411. This makes it possible to suppress transmission of vibration from the

internal gears

74, 74A to 74C, and 74E to 74L to the first and

second housings

30 and 40 through the contact surface portions 411.

Further, although the description is directed to a case where a separate structural unit for the internal gear and the housing is used for a part of the planetary gear device, the present application is not limited thereto, but may be used as a part of another gear mechanism.

In the above embodiment, the planetary gear mechanism of the planetary gear device is realized by three planetary gears; however, the present invention is not limited thereto. In the present invention, the planetary gear device may be realized by using a planetary gear mechanism having, for example, a single planetary gear or a plurality of (other than three) planetary gears.

Further, the planetary gear device of the present invention can be applied to various machines and apparatuses using a reduction mechanism or an acceleration mechanism, such as automobiles, robots, industrial equipment, playground equipment, and the like.

Further, instead of the structure in which the movement within the housing is restricted by making the line contact in the axial direction between the movement restricting convex portion (first convex portion) and the stopper pair (second convex portion) in the above-described embodiment, the structure may be a structure in which the movement within the housing is restricted by point contact between the movement restricting convex portion (first convex portion) and the stopper pair (second convex portion). More specifically, the stopper pair (second convex portion) 45 in fig. 5 may have a shape discontinuous in the axial direction, and the movement restricting convex portion (first convex portion) 75 in fig. 7 may have a shape discontinuous in the axial direction.

[ description of reference symbols]

1: actuator

10: motor with a stator having a stator core

11: motor host

12: rotating shaft

20: planetary gear device

30: first shell

30 a: opening of the container

40: second shell

41: first position

42: second position

43: third position

43 a: opening of the container

44: cylinder

44 a: inner wall

45: retainer (second convex part)

45 a: upright part

45 b: connecting part

45 c: top part

46: cylinder

47: internal tooth part

50: shell body

60: planetary gear mechanism

70: first planetary gear mechanism

71: sun gear

71 a: sun gear part

72: planetary gear

72 a: planetary gear portion

73: support frame

73 a: receiving opening

74. 74A, 74B, 74C, 74D, 74E, 74F, 74G, 74H, 74I, 74J, 74K, 74L: internal gear

74 a: internal tooth part

74 b: outer peripheral surface

75: movement restricting convex portion (first convex portion)

75 a: inclined edge portion

75 b: top part

75 c: notched portion

76: pin

80: second planetary gear mechanism

81: sun gear

81 a: sun gear part

82: planetary gear

82 a: planetary gear portion

83: support frame

84: gear holding part

84 a: receiving opening

85: output shaft holding part

85 a: assembly hole

86: output shaft

86 a: output gear

87: pin

90: contact area

140: second shell

141: female part

174: internal gear

175: movement restricting convex portion (first convex portion)

411: contact surface portion

740. 740A, 740B, 740C, 740D, 740E, 740F, 740G, 740H, 740I, 740J, 740K, 740L: open face

742. 742A, 742B, 742C, 742D, 742E, 742F, 742G, 742H, 742I, 742J, 742K, 742L: contact projection

7421: inner surface

Claims

1. An apparatus for suppressing noise generated in a planetary gear device, comprising:

an internal gear having: having an inner peripheral surface on which an internal tooth portion is formed; wherein the internal gear has an outer peripheral surface having a convex portion formed on at least a part thereof in a direction from one side to the other side in an axial direction of the internal gear, and wherein the internal gear has an open end surface extending between the inner peripheral surface and the outer peripheral surface on an end portion on the other side of the internal gear; and

a substantially cylindrical housing for accommodating the internal gear, wherein movement of the internal gear in a circumferential direction within the housing is restricted by contact with the convex portion of the internal gear,

wherein the housing has a contact surface portion which is provided so as to face the opening end surface on the other side of the internal gear, and

wherein the opening end surface on the other side of the internal gear has a contact portion protruding toward a contact surface portion side, wherein the contact portion restricts movement of the internal gear toward the contact surface portion side by contact with the contact surface portion in the axial direction.

2. The apparatus according to claim 1, wherein the contact portion includes at least three contact convex portions that make point contact with the contact surface portion.

3. The apparatus according to claim 1, wherein the contact portion includes a plurality of contact portions protruding from the contact surface portion side, and wherein the plurality of contact portions are provided on the opening end face at equal intervals in the circumferential direction.

4. The apparatus according to claim 1, wherein the contact portion includes a plurality of contact portions protruding from the contact surface portion side, and wherein the plurality of contact portions are provided at unequal intervals in the circumferential direction on the open end face.

5. The apparatus according to any one of claims 1 to 4, wherein the contact portion is configured such that the area of a cross section thereof perpendicular to the axial direction is smaller the farther away from the open end face of the other side.

6. The apparatus according to any one of claims 1 to 4, wherein the contact portion is a pyramid or a conical body, wherein a tip portion on the contact surface portion side is a top.

7. The apparatus according to any one of claims 1 to 4, characterized in that in the contact portion, a tip portion of the contact surface portion has a spherical surface shape.

8. The apparatus according to any one of claims 1 to 4, wherein the contact portion has a rod-like extension portion extending from the opening end face toward the contact surface portion, and a hemispherical surface portion provided on a tip of the extension portion.

9. The apparatus according to any one of claims 1 to 4, wherein the contact portion has a cross-sectional shape in a cross-section perpendicular to the axial direction that is a plus sign shape.

10. The apparatus according to any one of claims 1 to 4, characterized in that a second contact portion is provided to protrude from the one side on the open end face on the one side.

11. The apparatus according to any one of claims 1 to 4, characterized in that the internal gear and the housing are made of synthetic resin, and

wherein the internal gear is formed of a synthetic resin having a hardness smaller than that of the synthetic resin for forming the housing.

12. A planetary gear device, comprising:

the apparatus for suppressing noise generated in a planetary gear device according to any one of claims 1 to 4;

at least one planetary gear engaged with the internal gear,

a sun gear meshed with the at least one planetary gear and positioned at a radial center along the housing; and

a carrier rotatably supporting the one or more planet gears.

13. The planetary gear arrangement as in claim 12, further comprising:

a second sun gear that rotates with rotation of the carrier;

one or more second planet gears disposed on a periphery of the second sun gear and meshed with the second sun gear;

a second carrier rotatably supporting the one or more second planet gears; and

a second housing having internal teeth engaged with the one or more second planetary gears formed on an inner peripheral surface thereof, wherein the housing and the second housing are integrally formed.

14. A planetary gear device, comprising:

at least two-stage planetary gear mechanism, each stage planetary gear mechanism includes:

a sun gear;

one or more planet gears arranged on the periphery of the sun gear for meshing with the sun gear; and

a carrier rotatably supporting the one or more planetary gears, wherein in the at least two-stage planetary gear mechanism, a planetary gear mechanism that operates at the highest speed includes the apparatus for suppressing noise generated in a planetary gear device according to any one of claims 1 to 4, wherein the one or more planetary gears of the planetary gear mechanism are meshed with the internal gear, and

wherein in the at least two-stage planetary gear mechanism, the planetary gear mechanism that operates at the lowest speed includes a housing that includes internal teeth that are formed on an inner peripheral surface of the housing and that mesh with the one or more planetary gears of the planetary gear mechanism.

15. An actuator, comprising:

the planetary gear arrangement according to claim 12; and

a motor connected to the planetary gear arrangement for driving the planetary gear arrangement.