WO2020110823A1

WO2020110823A1 - Disc brake

Info

Publication number: WO2020110823A1
Application number: PCT/JP2019/045201
Authority: WO
Inventors: 力弥吉津; 厚志小平
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2018-11-27
Filing date: 2019-11-19
Publication date: 2020-06-04
Also published as: JP2022028979A

Abstract

This disc brake is provided with a first reduction gear to which rotation from an electric motor is transmitted, and a planetary gear reduction mechanism to which rotation from the first reduction gear is transmitted. The first reduction gear includes a stepped gear having a large-diameter gear and a small-diameter gear. The large-diameter gear and a carrier to which rotation from the planetary gear reduction mechanism is transmitted are arranged so as to overlap radially. Thus, with the disc brake, it is possible to achieve axial size reduction and to improve ease of mounting on a vehicle.

Description

Disc brake

The present invention relates to a disc brake used for braking a vehicle.

As the disc brake, for example, the disc brake described in Patent Document 1 includes a spur tooth multi-stage reduction mechanism and a planetary gear reduction mechanism to which rotation from an electric motor is transmitted, and a spur tooth multi-stage reduction mechanism and a planetary gear reduction mechanism. And a piston propulsion mechanism that propels the piston by rotational torque. The spur gear multi-stage reduction mechanism includes a pinion gear, a first reduction gear that meshes with the pinion gear, a non-reduction spur gear that meshes with the first reduction gear, and a second reduction gear that meshes with the non-reduction spur gear. The first reduction gear is configured such that a large gear meshing with the pinion gear and a small gear are integrally and concentrically connected to each other. The planetary gear reduction mechanism includes a sun gear, planetary gears, and an internal gear, and a carrier is connected to each planetary gear. In the disc brake of Patent Document 1, the large gear of the first reduction gear and the carrier are arranged at different positions along the axial direction.

JP, 2008-17300, A

The main problem of the disc brake according to Patent Document 1 described above is that the large gear of the first reduction gear and the carrier are arranged at mutually different positions along the axial direction. There is a risk that the size will increase along the line. Further, in the disc brake according to Patent Document 1, since a non-reducing spur gear is provided as the spur gear multi-step reduction mechanism, the number of parts thereof is large and needs to be improved. Further, in the disc brake according to Patent Document 1, in the first stage, that is, the reduction ratio between the pinion gear and the large gear is small, the output of the electric motor is increased to obtain a desired output, or the rotation is a piston propulsion mechanism. Although it is necessary to reduce the lead of the direct-acting conversion mechanism (efficiency reduction), both are not preferable in terms of performance.

The object of the present invention is to provide a disc brake that reduces the number of parts and enables miniaturization to improve mountability in a vehicle.

One embodiment of the present invention is a disc brake that pushes a braking member against a member to be braked by propelling a piston by transmitting a driving force of an electric motor to a rotation/linear motion conversion mechanism via a speed reduction mechanism, The reduction mechanism includes a reduction gear to which the rotation from the electric motor is transmitted, and a planetary gear reduction mechanism to which the rotation from the reduction gear is transmitted, and the reduction gear includes a large diameter gear and a small diameter gear. The stepped gear is included, and the large-diameter gear and the carrier to which the rotation from the planetary gear reduction mechanism is transmitted are arranged so as to overlap in the radial direction.

According to the disc brake according to the embodiment of the present invention, the number of parts can be reduced, the disc brake can be downsized, and the mountability on the vehicle can be improved.

Sectional drawing of the principal part of the disc brake which concerns on this embodiment. The enlarged view of the principal part of FIG. The principal part exploded perspective view of the disc brake concerning this embodiment.

Hereinafter, the present embodiment will be described in detail with reference to FIGS. 1 to 3.
The disc brake 1 according to the present embodiment is an electric brake device that generates a braking force by driving an electric motor 40 as an electric motor during normal traveling. In the following description, the inside of the vehicle (inner side) will be referred to as one end side (cover member 36 side), and the outside of the vehicle (outer side) will be referred to as the other end side (disk rotor D side), and will be described as appropriate. That is, in FIGS. 1 and 2, the right side is referred to as one end side, and the left side is referred to as the other end side, which will be described as appropriate. As shown in FIG. 1, the disc brake 1 according to the present embodiment includes a pair of braking members, which are attached to a rotating portion of a vehicle and are arranged on both sides in the axial direction with a disc rotor D serving as a braked member interposed therebetween. The inner brake pad 2, the outer brake pad 3, and the caliper 4 of FIG. The disc brake 1 is configured as a caliper floating type. The pair of inner brake pads 2 and outer brake pads 3 and the caliper 4 are supported by a bracket 5 fixed to a non-rotating portion such as a knuckle of a vehicle so as to be movable in the axial direction of the disc rotor D.

As shown in FIGS. 1 and 2, the caliper 4 includes a caliper body 8 that is a main body of the caliper 4, and a drive mechanism 9 that applies a thrust force to a piston 18 in a cylinder portion 13 of the caliper body 8. .. The caliper main body 8 is arranged on the base end side facing the inner brake pad 2, and has a cylindrical cylinder portion 13 facing the inner brake pad 2 and opening, and the outer side of the cylinder portion 13 across the disc rotor D. And a pair of

claw portions

14, 14 that are disposed on the front end side facing the outer brake pad 3.

A piston 18 is housed in the cylinder portion 13 of the caliper body 8, that is, in the cylinder bore 16 of the cylinder portion 13 such that the piston 18 cannot rotate relative to the cylinder portion 13 and can move in the axial direction. The piston 18 presses the inner brake pad 2, and is formed in a bottomed cup shape. The piston 18 is housed in the cylinder bore 16 of the cylinder portion 13 so that the bottom thereof faces the inner brake pad 2. The piston 18 is non-rotatably supported with respect to the cylinder bore 16 and, by extension, the caliper body 8 by the detent engagement between the bottom of the piston 18 and the inner brake pad 2.

A seal member (not shown) is arranged on the inner peripheral surface of the other end of the cylinder bore 16 of the cylinder portion 13. The piston 18 is housed in the cylinder bore 16 so as to be movable in the axial direction while being in contact with the seal member. A dust boot 20 is interposed between the outer peripheral surface on the bottom side of the piston 18 and the inner peripheral surface on the other end side of the cylinder bore 16. The seal member and the dust boot 20 prevent foreign matter from entering the cylinder bore 16 of the cylinder portion 13.

A gear housing 25 is integrally connected to the bottom wall 23 side (one end side) of the cylinder portion 13 of the caliper body 8. The motor gear assembly 30 is housed inside the gear housing 25. The motor gear assembly 30 is an electric motor 40, a spur gear multi-stage speed reduction mechanism 41, and a planetary gear speed reduction mechanism 42, which will be described later. Referring also to FIG. 3, the gear housing 25 includes a first gear housing 27 that houses the electric motor 40, and a second gear housing 28 that mainly houses the planetary gear reduction mechanism 42. The bottom wall 23 of the cylinder portion 13 is integrally connected to the first gear housing 27 from the other end side. As a result, the cylinder portion 13 and the first gear housing 27 (electric motor 40) are arranged substantially parallel to each other. The second gear housing 28 is formed with an insertion hole 29 into which a small-diameter cylindrical portion 86 of the carrier 72 including a spindle 93 described later is inserted.

As shown in FIG. 2, from the bottom surface of the second gear housing 28, a cylindrical restraining portion 32 that restricts radial movement of an internal gear 71, which will be described later, is provided in a protruding manner. An annular groove 33 is formed on the outer side in the radial direction of the cylindrical restraining portion 32 between the cylindrical restraining portion 32 and a wall surface facing it. A plurality of engagement recesses 34 are formed at intervals in the circumferential direction on the wall surface facing the cylindrical restraint portion 32. A cutout portion (not shown) is formed in the cylindrical restraint portion 32 so as to avoid interference with the large-diameter gear 53 of the first reduction gear 48 described later. In other words, the cylindrical restraint 32 has a notch (not shown) into which the large-diameter gear 53 of the first reduction gear 48, which will be described later, is inserted. The one end side opening of the gear housing 25 is closed by a cover member 36. The cover member 36 is airtightly attached to the gear housing 25.

The drive mechanism 9 includes an electric motor 40, a spur gear multi-step speed reduction mechanism 41 and a planetary gear speed reduction mechanism 42 as a speed reduction mechanism that increases the rotational torque from the electric motor 40, and the rotation from the planetary gear speed reduction mechanism 42 is linear. A rotation/linear motion conversion mechanism 43 that converts the motion into a motion and applies a thrust to the piston 18 is provided. As described above, the electric motor 40 is arranged in the first gear housing 27, and its rotation shaft 40A extends toward the cover member 36 (one end side). Note that FIG. 3 illustrates a part of the electric motor 40. The spur gear multi-step reduction mechanism 41 includes a pinion gear 47, a first reduction gear 48 as a reduction gear, and a second reduction gear 49. The first reduction gear 48 and the second reduction gear 49 are made of metal or resin such as fiber reinforced resin.

Referring also to FIG. 3, the pinion gear 47 is formed in a tubular shape, and is press-fitted and fixed to the rotary shaft 40A of the electric motor 40. The first reduction gear 48 is a stepped gear. The first reduction gear 48 includes a large diameter large diameter gear 53 meshing with the pinion gear 47, and a small diameter small diameter gear 54 concentrically extending from the large diameter gear 53 toward one end side in the axial direction. .. The central portion of the first reduction gear 48 in the radial direction is arranged near the boundary between the first gear housing 27 and the second gear housing 28. In other words, the large diameter gear 53 is arranged so as to straddle the first gear housing 27 and the second gear housing 28. A support rod 60 is rotatably supported on the first reduction gear 48. The support rod 60 is press-fitted and fixed to the bottom surface of the gear housing 25. The axial length of the small diameter gear 54 is formed to be considerably longer than the axial length of the large diameter gear 53. The axial length of the small diameter gear 54 is substantially the same as the axial length of the large diameter gear 57 of the second reduction gear 49 described later. One end of the small diameter gear 54 is arranged close to the cover member 36.

The small diameter gear 54 of the first reduction gear 48 meshes with the second reduction gear 49. The second reduction gear 49 has a large diameter large diameter gear 57 that meshes with the small diameter gear 54 of the first reduction gear 48, and a small diameter sun gear concentrically extending from the large diameter gear 57 toward the other end in the axial direction. And 58. The second reduction gear 49 is housed in the second gear housing 28. A support hole 62 penetrating in the axial direction is formed in the radial center of the second reduction gear 49. A support shaft portion 95 of a spindle 93 described later is rotatably inserted into the support hole 62. As a result, the second reduction gear 49 is rotatably supported by the gear housing 25.

The sun gear 58 is configured as a part of the planetary gear speed reduction mechanism 42. The large-diameter gear 57 and the sun gear 58 have substantially the same axial length. An annular space 63 is formed between the inner peripheral surface of the large diameter gear 57 and the outer peripheral surface of the sun gear 58. One end of the large diameter gear 57 of the second reduction gear 49 and one end of the sun gear 58 are connected by an annular ring wall portion 65. An annular stopper portion 66 protruding toward the planetary gear speed reduction mechanism 42 side (the other end side) is formed on the other end side surface of the annular wall portion 65 near the outer peripheral end thereof. The annular wall portion 65 of the second reduction gear 49 is arranged near the cover member 36.

The planetary gear reduction mechanism 42 includes a sun gear 58 of the second reduction gear 49, a plurality (five in this embodiment) of planetary gears 70, and an internal gear 71. The rotation from the planetary gear reduction mechanism 42, that is, the rotation from each planetary gear 70 is transmitted to the carrier 72. Each planetary gear 70 has a gear 75 that meshes with the sun gear 58, and a hole portion 76 into which a pin 90 standing from a carrier 72 is rotatably inserted. The planetary gears 70 are arranged around the sun gear 58 at equal intervals along the circumferential direction. Specifically, each planetary gear 70 is arranged at equal intervals along the circumferential direction in an annular space 63 between the inner peripheral surface of the large diameter gear 57 and the outer peripheral surface of the sun gear 58 while meshing with the sun gear 58.

The internal gear 71 has internal teeth 78 that mesh with the gears 75 of the planetary gears 70, and an annular wall that continuously extends from one end of the internal teeth 78 toward the radial center and restricts the axial movement of each planetary gear 70. A portion 79 and a cylindrical wall portion 80 extending from the inner teeth 78 toward the other end side are provided. The portion of the internal gear 78 of the internal gear 71 is arranged between the inner peripheral surface of the large diameter gear 57 of the second reduction gear 49 and each planetary gear 70. The inner teeth 78 of the internal gear 71, the planetary gears 70, and the sun gear 58 have surfaces on the other end sides that are substantially flush with each other. As can be seen from FIG. 3, the cylindrical wall portion 80 of the internal gear 71 is provided with a plurality of engaging projections 82 projecting outward in the radial direction at intervals in the circumferential direction. In the present embodiment, the engaging protrusions 82 are formed at three equal intervals.

As can be seen from FIG. 3, the cylindrical wall portion 80 of the internal gear 71 is provided with a cutout portion 83 at a portion thereof in the circumferential direction so as to avoid interference with the large diameter gear 53 of the first reduction gear 48. It is formed. In other words, the cylindrical wall portion 80 of the internal gear 71 is formed with a notch portion 83 in which the large-diameter gear 53 of the first reduction gear 48 is inserted, in a portion in the circumferential direction thereof. Then, one end surface of the cylindrical wall portion 80 of the internal gear 71 is brought into contact with the bottom surface of the second gear housing 28, while the inner peripheral surface of the cylindrical wall portion 80 is in contact with the cylindrical restraining portion 32 of the second gear housing 28. The engaging projections 82 protruding from the cylindrical wall 80 are engaged with the engaging recesses 34 provided on the wall surface of the second gear housing 28. Further, an annular stopper portion 66 provided on the annular wall portion 65 of the second reduction gear 49 is in contact with the surface of the internal gear 71 on the one end side. As a result, the internal gear 71 is restricted from moving in the radial direction and the axial direction, and is supported so as not to rotate relative to the gear housing 25.

The carrier 72 includes a large-diameter annular plate-shaped portion 85 and a small-diameter cylindrical portion 86 that is concentrically projected from the large-diameter annular plate-shaped portion 85 on the other end side. The carrier 72 is formed so that the spline hole portion 87 penetrates in the axial direction substantially at the center in the radial direction. The large-diameter annular plate-shaped portion 85 is arranged inside the cylindrical restraining portion 32 of the second gear housing 28. On the outer peripheral side of the large-diameter annular plate-shaped portion 85 of the carrier 72, a plurality of pin hole portions 89 are formed at intervals along the circumferential direction so as to correspond to the planetary gears 70. A pin 90 is press-fitted and fixed in each pin hole 89. Each pin 90 is rotatably inserted in the hole 76 of each planetary gear 70. The small-diameter cylindrical portion 86 of the carrier 72 is inserted into the insertion hole 29 of the second gear housing 28. The small-diameter cylindrical portion 86 of the carrier 72 and the insertion hole 29 have substantially the same axial length.

The outer diameter of the carrier 72 is smaller than the inner diameter of the inner teeth 78 of the internal gear 71. The thickness of the large-diameter annular plate-shaped portion 85 of the carrier 72 is substantially the same as the height of the cylindrical restraining portion 32 provided in the second gear housing 28. The large-diameter annular plate-shaped portion 85 of the carrier 72 is formed to be slightly thicker than the tooth width (thickness) of the large-diameter gear 53 of the first reduction gear 48. The carrier 72, more specifically, the large-diameter annular plate-shaped portion 85 of the carrier 72 and the large-diameter gear 53 of the first reduction gear 48 are arranged so as to overlap in the radial direction. In other words, the large-diameter gear 53 of the first reduction gear 48 is located within the axial range of the carrier 72, specifically within the axial range of the large-diameter annular plate portion 85 of the carrier 72. The large-diameter gear 53 of the first reduction gear 48 has a notch (not shown) provided in the cylindrical restraint 32 of the second gear housing 28 and a notch provided in the cylindrical wall 80 of the internal gear 71. It is arranged so as to enter the portion 83. As a result, the outer peripheral surface of the large-diameter annular plate-shaped portion 85 of the carrier 72 and the outer peripheral surface of the large-diameter gear 53 of the first reduction gear 48 are arranged facing each other and close to each other.

Rotation from the carrier 72 is transmitted to the spindle 93, and its rotational torque is transmitted to the rotation/linear motion conversion mechanism 43. The spindle 93 is connected to the support shaft portion 95 that is inserted into the support hole 62 of the second reduction gear 49, the support shaft portion 95, and the spline shaft portion 96 that is engaged with the spline hole portion 87 of the carrier 72. And a main shaft portion (not shown) that is integrally connected to the spline shaft portion 96 and extends into the cylinder bore 16 and functions as a part of the rotation/linear motion conversion mechanism 43. The support shaft portion 95 of the spindle 93 is rotatably inserted into the support hole 62 of the second reduction gear 49, so that the second reduction gear 49 is rotatably supported by the gear housing 25. Further, since the spline shaft portion 96 of the spindle 93 engages with the spline hole portion 87 of the carrier 72, rotational torque can be transmitted between the carrier 72 and the spindle 93.

The rotating shaft 40A of the electric motor 40 projects from the pinion gear 47 to one end side. A ratchet gear 100 is press-fitted and fixed to one end of a rotating shaft 40A of the electric motor 40. By engaging a lever member (not shown) with the ratchet gear 100, the thrust of the piston 18 to the inner brake pad 2 can be held. The rotation angle detecting means 103 is arranged on one end side of the ratchet gear 100. The rotation angle detection means 103 detects the rotation angle of the rotation shaft 40A of the electric motor 40. The rotation angle detection means 103 includes a magnet member 106 and a magnetic detection IC chip 107.

A press-fitting recess 109 is formed on one end surface of the rotating shaft 40A of the electric motor 40. The support rod 110 is press-fitted and fixed in the press-fitting recess 109. The support rod 110 supports the ring-shaped magnet member 106 arranged in the cup-shaped support member 113. The magnetic detection IC chip 107 is arranged so as to face one end side of the magnet member 106. The magnetic detection IC chip 107 detects changes in the magnetic field generated from the magnet member 106. The magnetic detection IC chip 107 is attached to the control board 116. Then, the magnetic detection IC chip 107 detects the change in the magnetic flux from the magnet member 106 that rotates with the rotation of the rotation shaft 40A, and the control board 116 calculates the rotation angle of the rotation shaft 40A of the electric motor 40. Is being detected.

As shown in FIG. 1, the rotation/linear motion converting mechanism 43 converts the rotary motion from the spur gear multi-stage speed reducing mechanism 41 and the planetary gear speed reducing mechanism 42, that is, the rotary motion of the spindle 93 into a linear motion (hereinafter, referred to as a direct motion for convenience). The thrust is applied to the piston 18 by conversion and movement of the linear motion member (not shown). The rotation/linear motion conversion mechanism 43 is arranged inside the cylinder bore 16 and between the bottom surface and the piston 18. When the spindle 93 rotates as the carrier 72 rotates, the rotation/linear motion converting mechanism 43 advances the linear motion member toward the other end side, whereby the piston 18 advances and the piston 18 moves. The inner brake pad 2 can be pressed against the disc rotor D.

The drive of the electric motor 40 is controlled by a command from the control board 116. At the time of braking during normal traveling, the control board 116 causes detection signals from a detection sensor corresponding to a driver's request, various detection sensors for detecting various situations in which a brake is required, and detection from the rotation angle detection means 103. The drive of the electric motor 40 is controlled based on the signal and a detection signal from a thrust sensor (not shown) or the like.

Next, in the disc brake 1 according to the present embodiment, the operation of braking and braking release during normal traveling will be described.
At the time of braking during normal traveling, the electric motor 40 is driven by a command from the control board 116, and the rotation thereof in the positive direction, that is, the braking direction is changed by the sun gear 58 of the planetary gear speed reduction mechanism 42 via the spur gear multi-speed reduction mechanism 41. Be transmitted to. The rotation of the sun gear 58 of the planetary gear speed reduction mechanism 42 causes the planetary gears 70 to revolve around the rotation axis of the sun gear 58 while rotating around the rotation axis of the planetary gear 70, thereby rotating the carrier 72. That is, the rotation from the electric motor 40 is decelerated and increased at a predetermined reduction ratio by passing through the spur gear multi-stage speed reduction mechanism 41 and the planetary gear speed reduction mechanism 42, and is transmitted to the carrier 72. Then, the rotation from the carrier 72 is transmitted to the spindle 93.

Next, when the spindle 93 rotates with the rotation of the carrier 72, the linear motion converting mechanism 43 causes the linear motion member to move forward to move the piston 18 forward. As the piston 18 moves forward, the inner brake pad 2 is pressed against the disc rotor D. Then, the caliper body 8 moves to the inner side with respect to the bracket 5 by the reaction force against the pressing force of the piston 18 against the inner brake pad 2, and the outer brake pad 3 is moved to the disc rotor D by the

claw portions

14 and 14. Press down. As a result, the disc rotor D is sandwiched between the pair of inner and

outer brake pads

2 and 3 to generate a frictional force, which in turn causes a braking force of the vehicle.

On the other hand, at the time of releasing the braking, the rotating shaft 40A of the electric motor 40 rotates in the reverse direction, that is, in the braking releasing direction by the command from the control board 116, and the rotation in the reverse direction causes the spur gear multi-step speed reduction mechanism 41 and the planetary gear speed reduction. It is transmitted to the spindle 93 via the mechanism 42. As a result, by the rotation of the spindle 93 in the opposite direction, the linear motion member is retracted and returned to the initial state by the action of the rotation/linear motion conversion mechanism 43, and the pair of inner and outer brake pads 2 to the disc rotor D, The braking force by 3 is released.

As described above, in the disc brake 1 according to the present embodiment, particularly in the motor gear assembly 30, the large diameter gear 53 of the first reduction gear 48 and the carrier 72, specifically, the large diameter annular plate shape of the carrier 72. The portion 85 is arranged so as to overlap in the radial direction. In other words, the large-diameter gear 53 of the first reduction gear 48 is located within the axial range of the carrier 72, specifically within the axial range of the large-diameter annular plate portion 85 of the carrier 72. As a result, the present disc brake 1 can be downsized along the axial direction, and the mountability on the vehicle can be improved. Further, in the disc brake 1 according to the present embodiment, the small diameter gear 54 of the first reduction gear 48 directly meshes with the large diameter gear 57 of the second reduction gear 49, which is a non-deceleration gear adopted in the conventional disc brake. Since no spur gear is required, the number of parts can be reduced.

Further, in the disc brake 1 according to the present embodiment, the large diameter gear 53 of the first reduction gear 48 enters the cutout portion 83 provided in the cylindrical wall portion 80 of the internal gear 71, and the large diameter gear 53 of the large reduction gear 53 is The outer peripheral surface and the outer peripheral surface of the large-diameter annular plate-shaped portion 85 of the carrier 72 are arranged facing each other and close to each other. As a result, the outer diameter of the large-diameter gear 53 can be maximized, and the reduction ratio between the pinion gear 47 and the large-diameter gear 53 can be increased, so that the output of the electric motor 40 is increased or the rotation is reduced. It is not necessary to take measures such as reducing the lead of the linear motion converting mechanism 43, and the performance is good.

In the above description, the present embodiment is adopted in the disc brake 1 as the electric brake device, but the present embodiment is applied to the brake supplied to the inside of the cylinder bore 16 of the caliper body 8 during braking during normal traveling. By moving the piston 18 forward by hydraulic pressure, a braking force is generated by the pair of inner and

outer brake pads

2 and 3, and the driving force from the drive mechanism 9, that is, the electric motor 40, is generated during parking braking such as parking. Is transmitted to the piston 18 via the spur gear multi-stage speed reduction mechanism 41, the planetary gear speed reduction mechanism 42, and the rotation/linear motion conversion mechanism 43, so that the piston 18 is advanced and is controlled by the pair of inner and

outer brake pads

2, 3. It may be used for disc brakes that generate power.

As the disc brake 1 according to the present embodiment described above, for example, the disc brake 1 having the following modes can be considered.
In the first mode, the driving force of the electric motor (40) is transmitted to the rotation/linear motion conversion mechanism (43) via the speed reduction mechanism (42, 48) to propel the piston (18) and the braking member ( A disc brake (1) for pressing the braked members (D) against the braked member (D), wherein the reduction mechanism (42, 48) is a reduction gear (48) to which rotation from the electric motor (40) is transmitted. And a planetary gear reduction mechanism (42) to which the rotation from the reduction gear (48) is transmitted, the reduction gear (48) having a large diameter gear (53) and a small diameter gear (54). The large-diameter gear (53) including an additional gear and the carrier (72) to which the rotation from the planetary gear reduction mechanism (42) is transmitted are arranged so as to overlap in the radial direction.

In the second aspect, in the first aspect, the outer peripheral surface of the large-diameter gear (53) and the outer peripheral surface of the carrier (72) face each other and are arranged close to each other.
According to a third aspect, in the first or second aspect, the planetary gear reduction mechanism (42) includes a sun gear (58), a plurality of planetary gears (70) meshing with the sun gear (58), and the planetary gears (70). 70) which meshes with the internal gear (71), and the internal gear (71) is formed with a cutout portion (83), and a part of the large diameter gear (53) is cut off. It is arranged so as to enter the notch (83).

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are included. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those including all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add/delete/replace other configurations with respect to a part of the configurations of the respective embodiments.

This application claims priority based on Japanese Patent Application No. 2018-212294 filed on November 27, 2018. The entire disclosure of Japanese Patent Application No. 2018-212294, filed Nov. 27, 2018, including the specification, claims, drawings, and abstract, is incorporated herein by reference in its entirety.

1 disc brake, 2 inner brake pad (braking member), 3 outer brake pad (braking member), 4 caliper, 8 caliper body, 18 piston, 40 electric motor (electric motor), 41 spur gear multi-stage reduction mechanism, 42 planetary gear reduction Mechanism, 43 rotation/linear motion conversion mechanism, 48 first reduction gear (reduction gear), 53 large diameter gear, 54 small diameter gear, 58 sun gear, 70 planetary gear, 71 internal gear, 72 carrier, 83 notch portion, 85 large diameter Annular plate-shaped part, D disk rotor (braked member)

Claims

A disc brake for propelling a piston by transmitting a driving force of an electric motor to a rotation/linear motion converting mechanism via a reduction mechanism, and pressing a braking member against a braked member,
The reduction mechanism includes a reduction gear to which rotation from the electric motor is transmitted, and a planetary gear reduction mechanism to which rotation from the reduction gear is transmitted,
The reduction gear includes a stepped gear having a large diameter gear and a small diameter gear,
The disc brake, wherein the large-diameter gear and the carrier to which the rotation from the planetary gear reduction mechanism is transmitted are arranged so as to overlap in the radial direction.
The disc brake according to claim 1,
The disc brake, wherein the outer peripheral surface of the large-diameter gear and the outer peripheral surface of the carrier are arranged facing each other and in close proximity to each other.
The disc brake according to claim 1,
The planetary gear reduction mechanism includes a sun gear, a plurality of planetary gears that mesh with the sun gear, and an internal gear that meshes with each planetary gear,
A disc brake, wherein a cutout portion is formed in the internal gear, and a part of the large-diameter gear is arranged so as to enter the cutout portion.
The disc brake according to claim 2,
The planetary gear reduction mechanism includes a sun gear, a plurality of planetary gears that mesh with the sun gear, and an internal gear that meshes with each planetary gear,
A disc brake, wherein a cutout portion is formed in the internal gear, and a part of the large-diameter gear is arranged so as to enter the cutout portion.