JPH04236837A - Reduction gear - Google Patents

Abstract

PURPOSE:To prevent the occurrence of jolting owing to a backlash and to eliminate a need for regulation effected when a reduction gear is assembled in a state to be freed from jolting, in a reduction gear in which a solar gear and a planetary gear geared with an internal gear are located between input and output shafts and the planetary gear is rotatably supported. CONSTITUTION:The planetary gear pair part of the one support shaft 5 of adjoining planetary gears 2 and 2 is positioned eccentrically from the axis of the support shaft 5 and a means to energize the planetary gear pair part so that the pair part is swung in the revolving direction of the planetary gear 2 is provided. The swing direction of the planetary gear pair part is set in the direction of the adjoining planetary gears 2 side by means of the energizing means.

Description

[Detailed description of the invention]

0001

[Field of Application and Summary of the Invention] The present invention relates to a reduction gear, in particular,
For reduction gears using a planetary gear transmission mechanism, it is possible to eliminate transmission defects such as rattling due to backlash in the gear transmission part, and furthermore, it eliminates the need for adjustment work during assembly. It is something to do.

0002

[Prior Art and Problems] A speed reducer using a planetary gear transmission mechanism generally has a plurality of planetary gears 2, 2 meshed with a sun gear 11 provided on an input shaft 1, as shown in FIG. At the same time, these planetary gears 2, 2 are attached to the casing 4.
It meshes with an internal gear 41 provided in the. and,
Each of the planetary gears 2, 2 is rotatable by a shaft portion 5 provided on a side wall of a casing 4 or a shaft mounting plate 31 such as a disk portion rotatably provided separately from the casing 4. is supported by In addition, the one shown in the same figure is one in which the output shaft 3 is provided with a shaft mounting plate 31. The reduction gear of the above type has the advantage that it can be downsized due to its simple configuration and that the input shaft and output shaft can be set coaxially. However, in this case, since the speed is reduced by gear transmission, backlash occurs in the gear transmission part, which causes noise and poor transmission accuracy.

[0003] As a solution to this inconvenience, there are already
There is a device disclosed in Japanese Patent Application Laid-open No. 13939/1983, in which a part of the support shafts 5, 5 supporting the planetary gears 2, 2 and disposed on the shaft mounting plate 31 are eccentrically arranged. A shaft 51 is used, and the attitude of each eccentric shaft 51 in the eccentric direction is adjusted at the time of assembly. In this conventional device, by adjusting and fixing the eccentric direction posture of each eccentric shaft 51, it is possible to assemble the planetary gears 2, 2 and the gears with which they mesh so that rattling due to backlash does not occur. This makes it possible to perform deceleration transmission without the above-mentioned rattling. However, in this conventional device, when assembling the speed reducer, it is necessary to particularly adjust the attitude of the eccentric shaft 51 in the eccentric direction. Further, when used for a long period of time, new rattling due to backlash will occur due to wear of each gear transmission part, and in this case, it is necessary to readjust the eccentric direction of each eccentric shaft 51.

[0004] The present invention has been made in view of the above points, and includes ``a planetary gear 2, 2 that meshes with a sun gear 11 and an internal gear 41 is interposed between the input shaft 1 and the output shaft 3; 2, 2 on the shaft mounting plate 31
, 5, the object is to prevent rattling due to backlash from occurring over a long period of time in a "reducer gear rotatably supported by a gear reducer", and to eliminate the need for adjustment when assembling to a state where said rattling does not occur. . [Invention of Claim 1]

[0005]

[Technical Means] The technical means of the present invention taken to solve the above-mentioned problems is as follows. Consisting of an eccentric cylinder 53 that is screwed to the fixed shaft 52 and rotatably supports the planetary gear 2, and a biasing means 54 that urges the eccentric cylinder 53 in the axial direction of the fixed shaft 52. In addition, by setting the torsion angle of the screw pair to be small, and setting the deflection direction of the eccentric cylinder 53 when it moves in the biasing direction by the biasing means 54 to the side of the other adjacent planetary gear 2. be.

[0006]

[Operation] The above technical means of the present invention operates as follows. Since the planetary gears 2, 2 are both rotatably (rotatably) supported by the support shafts 5, 5, the sun gear 1
1 and the internal gear 41 for gear transmission, forming a planetary gear transmission mechanism. During this transmission, at least one of the adjacent planetary gears 2, 2 is rotatably supported by an eccentric cylinder 53 that is eccentrically supported with respect to the fixed shaft 52. Furthermore, the eccentric cylinder 53 is threadedly mated with the fixed shaft 53 and biased in the axial direction, and the pairing relationship and the biasing direction are set in a predetermined relationship, so that the eccentric cylinder 53 is always fixed. It is biased to swing in one direction about the shaft 52, and the direction of this swing is set to face the other adjacent planetary gear 2.

Therefore, the rotation position of the teeth of the planetary gear 2 is fixed relative to the shaft mounting plate 31, and the teeth of the planetary gear 2 adjacent thereto and biased so as to swing in the direction of the planetary gear 2 as described above. The teeth of the sun gear 11 and the internal gear 41 that mesh with these are sandwiched by the teeth of the planetary gear 2. Moreover, this pinching force is always applied by the biasing force. As a result, in the transmission state, the sun gear 11...
The meshing portion between the pair of planetary gears 2, 2 and the internal gear 41 is free from rattling due to backlash. Further, even if the teeth of the meshing portion wear out, the biasing force eliminates rattling due to backlash in the new meshing state. Further, this meshing relationship is determined by the degree of eccentricity of the eccentric cylinder 53 that rotatably supports the planetary gear 2 and the relationship between the screw pair and the fixed shaft 52, but the degree of eccentricity and the torsion angle of the screw pair are determined in advance. If the degree is set to , the planetary gears 2, 2 can be assembled to the corresponding support shafts 5, 5 without rattling due to backlash. In addition, since the torsion angle of the threaded pair of the eccentric cylinder 53 and the biasing means 54 is set small, even if a force in the opposite direction to the biasing force in the swinging direction of the planetary gear 2 acts during transmission. , you don't have to worry about it swinging in the opposite direction.

[0008]

[Effects] Since the present invention has the above structure, it has the following unique effects. Even if the teeth of the meshing portion wear out, the biasing force eliminates backlash caused by backlash in the new meshing state, so no transmission errors occur over a long period of time. By simply assembling the planetary gears 2, 2 onto the corresponding support shafts 5, 5, they can be assembled without rattling due to backlash, so no adjustment is required during assembly.

[Invention of Claim 2] The invention of Claim 2 solves the same problem as the invention of Claim 1, and the bearing structure of one of the adjacent planetary gears 2, 2 is replaced with the other. This structure simplifies the support shaft 5.

[Technical means] The technical means of the invention of claim 2 is “
One of the support shafts 5 of the adjacent planetary gears 2, 2 is an eccentric shaft 51 attached to a shaft mounting plate 31, and this eccentric shaft 51 is screwed to the shaft mounting plate 31, and this eccentric shaft 51 is A biasing means for biasing in the axial direction biasing means 54
is provided between the shaft mounting plate 31 and the torsion angle of the screw pair portion to be small, and the deflection direction of the eccentric shaft 51 when moved in the biasing direction by the biasing means 54 is set to be similar to that of the other adjacent planet. It was set on the gear 2 side.

[Operation] In the device employing the above technical means of the invention of claim 2, the eccentric shaft 51 functions in the same manner as the eccentric cylinder 53 in the invention of claim 1, and the biasing means 54 acts on the eccentric shaft 51. The planetary gear 2 supported by 51 is always biased to swing toward the other planetary gear 2.

[Effects] In addition to having the same effect as the invention of claim 1, the structure of the support shaft 5 can be simplified because the support shaft 5 is constituted by an integral shaft.

0010

[Embodiment] The embodiment shown in FIGS. 1 to 3 is an embodiment of the invention according to claim 1, and in this embodiment, the planetary gears 2, 2 are mounted on a shaft mounting plate 31 provided on the output shaft 3. The planetary gears 2, 2 are freely supported and meshed with an internal gear 41 provided in the casing 4. Each of the planetary gears 2 is rotatably supported by support shafts 5, 5 attached to a shaft mounting plate 31. In this embodiment, four planetary gears 2, 2 are disposed on the shaft mounting plate 31 at 90 degree intervals, and the planetary gear 2 whose rotation position is fixed with respect to the shaft mounting plate 31 and the planetary gear 2 whose rotation position is fixed with respect to the shaft mounting plate 31, and Planetary gears 2 which are biased so as to swing in the direction of revolution of the gears 2 are arranged alternately. The support shaft 5 supporting the latter planetary gear 2 is composed of a fixed shaft 52 fixed to the shaft mounting plate 31 and projected therefrom, and an eccentric collar provided with a shaft hole 55 through which the fixed shaft 52 passes. This eccentric collar becomes an eccentric cylinder 53. As shown in FIG. 2, the inner peripheral surface of the shaft hole 55 is a torsion spline, and the paired portion of the fixed shaft 52 with the shaft hole 55 is also a torsion spline. These torsion splines are engaged with each other, and the fixed shaft 52 and the eccentric cylinder 53 are screwed together.

A disc spring serving as a biasing means 54 is interposed between the eccentric cylinder 53 and the shaft mounting plate 31, and the biasing force of the disc spring constantly biases the eccentric cylinder 53 in the advancing direction. There is. As a result, the planetary gears 2 that are paired around the eccentric cylinder 53 are urged to swing in the revolution direction. The other planetary gear 2, whose rotation position is fixed, has a normal support structure, and the fixed shaft protruding from the shaft mounting plate 31 becomes the support shaft 5, and is coaxial with the support shaft 5. The planetary gears 2 are supported in a rotating pair. With the above configuration, the planetary gears 2 whose rotational positions are fixed and the planetary gears 2 which are biased so that their rotational positions swing in the revolution direction alternate in succession.

In addition, in the latter planetary gear 2, as shown in FIG. Slightly backward in the revolution direction from direction R (opposite direction to the planetary gear 2 whose rotation position is fixed)
(0 to 0.5 mm). With the above configuration, the biasing force of the biasing means 54 biases one planetary gear 2 so that its rotational position swings in the direction of the other planetary gear 2 fixed on the shaft mounting plate 31. In addition, the torsion angle of the torsion spline formed in the shaft hole 55 and the fixed shaft 52 is 1 degree to 1 degree in this embodiment.
It is set to about 0 degrees. When trying to absorb an impact load when an overload is applied to the planetary gear 2 during transmission, it is preferable to set the deflection angle to about 4 to 8 degrees. This is because when an impact load is applied, the force pushes the planetary gear 2 toward the shaft mounting plate 31 against the urging force of the urging means 54.

Next, a second embodiment shown in FIGS. 4 and 5 corresponds to the embodiment of claim 2, and the sun gear 11
, the arrangement position of the internal gear 41 and the arrangement positions of the planetary gears 2, 2 are the same as in the first embodiment. Further, the planetary gears 2, 2 whose rotational position on the shaft mounting plate 31 is fixed, and the planetary gear 2, which is configured so that the rotational position can swing,
The arrangement relationship with No. 2 is also the same as in Example 1 above.

The difference from the first embodiment is in the shaft support structure of the latter planetary gears 2, 2. In the second embodiment, an eccentric head 57 is formed at the tip of the spline shaft 56 to support the eccentric shaft 5.
1, and has a structure in which the spline shaft 56 is passed through the shaft mounting plate 31 in a threaded pair. A biasing means 54 made of a disc spring is interposed between the shaft mounting plate 31 and the eccentric head 57. Thereby, the eccentric shaft 51 is urged to protrude toward the eccentric head 57 side. In this embodiment as well, the spline shaft 56 and the splines formed in the shaft hole 32 to which it is paired are slightly twisted as in the first embodiment, so that the eccentric shaft 51 is biased in the advancing direction. Then, the light maximum eccentric position P
is biased to swing in the direction of the arrow in FIG. As a result, the tooth 2 that meshes with the shaft mounting plate 31 is biased toward the adjacent tooth 2 (the one whose rotational position is fixed on the shaft mounting plate 31), which has the same effect as in the first embodiment. becomes.

Note that in any of the above embodiments, the eccentric cylinder 5
3 and the centers of the eccentric shafts 51 coincide with the centers of each planetary gear. Therefore, the center of the fixed shaft 52 and the center of the spline shaft 56 are located inside the circumference of the center arrangement of the planetary gears 2, 2. In particular, the support structure for the eccentric shaft 51 of this embodiment is distinctive. The spline shaft 56 is used as a small diameter portion, and is threadedly mated with the small diameter portion of the shaft hole 32, and the large diameter portions of both are mated with each other in a cylindrical shape. Therefore, the mounting position accuracy of the eccentric shaft 51 is ensured by this cylindrical pair. In other words, although the fitting tolerance of the threaded pair due to spline engagement cannot be reduced, this tolerance can be reduced in the cylindrical pair, so that the accuracy of the mounting position of the eccentric shaft 51 relative to the shaft mounting plate 31 can be ensured. The above-mentioned configuration in which the threaded pair portion and the cylindrical pair portion are combined can also be adopted for the fitting portion between the fixed shaft 52 and the planetary gear 2 in the first embodiment.

Further, although the shaft mounting plate 31 is provided integrally with the output shaft 3, it may be arranged on the side wall of the casing 4 as in the conventional example described above.
Other types of reducers may also be used. Furthermore, the adjacent planetary gears 2, 2 may both be provided so as to swing in the direction of the orbit, and the swing directions may be set in opposite directions, so that a biasing force in the swing direction is always applied. In addition to the above-mentioned embodiments, other known mechanisms can be used as a structure for applying biasing force in the deflection direction. Furthermore, each gear can also be a gear of another type, such as a helical gear.

[Brief explanation of the drawing]

[Fig. 1] Vertical front view of Example 1 of the present invention

[Figure 2] That X
-X sectional view

[Fig. 3] Detailed view of the shaft of the planetary gear 2 supported by the eccentric shaft

[Fig. 4] Longitudinal front view of Embodiment 2 of the present invention

[Figure 5] That Y
-Y cross section

[Fig. 6] Explanatory diagram of conventional example

[Explanation of symbols]

(1) Input shaft (5) Support shaft (3) Output shaft (51)
Eccentric shaft (11)‥‥‥Sun gear (52)‥‥‥
Fixed shaft (41)... Internal gear (53)...
‥Eccentric cylinder (2)‥‥‥Planetary gear (54)‥
‥‥Biasing means (31)‥‥‥Shaft mounting plate

Claims (2)

[Claims] Claim 1: A sun gear 11 between an input shaft 1 and an output shaft 3.
and planetary gears 2, 2 that mesh with the internal gear 41,
In a speed reducer in which the planetary gears 2, 2 are rotatably supported by support shafts 5, 5 provided on a shaft mounting plate 31,
At least one support shaft 5 of the adjacent planetary gears 2, 2 is coupled with a fixed shaft 52 attached to the shaft mounting plate 31, and the fixed shaft 52 is screwed to support the planetary gear 2 rotatably. an eccentric cylinder 53; and the eccentric cylinder 53 is connected to the fixed shaft 5.
2, and a biasing means 54 that biases the screw pair in the axial direction, and sets the torsion angle of the screw pair to be small, and the eccentric cylinder 5 when moved in the biasing direction by the biasing means 54.
3 is set to the other adjacent planetary gear 2 side. Claim 2: A sun gear 11 between the input shaft 1 and the output shaft 3.
and planetary gears 2, 2 that mesh with the internal gear 41,
In a reducer in which the planetary gears 2, 2 are rotatably supported by support shafts 5, 5 provided on a shaft mounting plate 31,
One of the support shafts 5 of the adjacent planetary gears 2, 2 is an eccentric shaft 51 attached to a shaft mounting plate 31, and this eccentric shaft 51 is screwed to the shaft mounting plate 31, and this eccentric shaft 51 is A biasing means 54 for biasing in the axial direction is provided between the shaft mounting plate 31 and the torsion angle of the pair of screws is set small, and the eccentric shaft when moved in the biasing direction by the biasing means 54 is set. A reduction gear in which the deflection direction of 51 is set to the other adjacent planetary gear 2 side.