JP7034023B2 - Disc brake - Google Patents

Description

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

As a conventional disc brake, Patent Document 1 discloses a deceleration mechanism for operating a parking disc brake used at the time of parking brake or the like. That is, in the invention of Patent Document 1, a planetary gear deceleration mechanism is adopted as the deceleration mechanism. The planetary gear reduction mechanism meshes with the sun gear of the second reduction gear, a plurality of planetary gears that mesh with the sun gear and are arranged at intervals along the outer peripheral surface thereof, and mesh with each planetary gear and are relative to the housing. It includes an internal gear that is non-rotatably supported, and a carrier that is press-fitted and fixed with a pin member that rotatably supports each planetary gear. Further, the second reduction gear is composed of a large gear to which the rotation from the motor is transmitted and a sun gear integrally extending in the axial direction from the radial center portion of the large gear. Then, the rotation from the motor is transmitted from the large gear of the second reduction gear to the carrier via the sun gear and each planetary gear.

Japanese Unexamined Patent Publication No. 2014-214830

Therefore, in the second reduction gear adopted in the invention of Patent Document 1, as the rotational torque from the motor increases, metallization is shifting to the gear portion of the sun gear in particular, and as its structure, insert molding is used. Proposed. However, in insert molding, an axial thickness for ensuring the rigidity of the metal portion buried in the large gear and an axial thickness for the resin portion for holding the resin are required, and the second reduction gear is used. The size increases along the axial direction, and the layout is deteriorated. Moreover, it is necessary to secure the relative position accuracy between the large gear of the second reduction gear and the sun gear, which increases the difficulty of the construction method and causes an increase in cost.

An object of the present invention is to provide a disc brake having a planetary gear reduction mechanism capable of suppressing an increase in size and cost.

As a means for solving the above problems, the present invention comprises a pair of pads arranged on both sides of the rotor in the axial direction, a piston that presses one of the pair of pads against the rotor, and the like. A caliper body having a cylinder in which a piston is movably housed, a motor provided in the caliper body, a deceleration mechanism including a planetary gear deceleration mechanism for increasing the rotational force from the motor, and a rotational motion from the deceleration mechanism. The planetary gear reduction mechanism is provided with a piston propulsion mechanism for propelling the piston by converting A small diameter gear that extends in the axial direction and has a smaller diameter than the large diameter gear, a plurality of planetary gears that mesh with the small diameter gear and are arranged at intervals along the outer peripheral surface of the small diameter gear, and an inter that meshes with each of the planetary gears. The small- diameter gear has a null gear, and at least the gear portion that meshes with the planetary gear is made of metal, and the large-diameter gear and the small-diameter gear are separated from each other. The relative rotation restricting portion is connected via the relative rotation restricting portion so as not to be able to rotate relative to each other, and the relative rotation restricting portion is characterized by including an arc surface protruding toward the radial center of the large-diameter gear .

According to the planetary gear reduction mechanism adopted for the disc brake of the present invention, insert molding can be eliminated as a method for manufacturing one component thereof, so that it is possible to suppress an increase in size and cost.

The cross-sectional view which shows the disc brake which concerns on this embodiment. The disc brake of FIG. 1 is an exploded perspective view of a motor gear assembly in a housing. The disc brake of FIG. 1 is an exploded perspective view of a motor gear assembly in a housing. FIG. 1 is an exploded perspective view of the second reduction gear incorporated in the housing of the disc brake of FIG. 1. The second reduction gear adopted for the disc brake of FIG. 1 is shown, (a) is a plan view from one end side, and (b) is a sectional view. FIG. 3 is an enlarged cross-sectional view of a rotary linear motion conversion mechanism adopted for the disc brake of FIG. 1. It is an exploded perspective view of the rotation linear motion conversion mechanism adopted for the disc brake of FIG. The second reduction gear according to another embodiment, (a) is a plan view from one end side, and (b) is a sectional view. The second reduction gear according to another embodiment, (a) is a plan view from one end side, and (b) is a sectional view. The second reduction gear according to another embodiment, (a) is a plan view from one end side, (b) is a sectional view, and (c) is a plan view from the other end side.

Hereinafter, this embodiment will be described in detail with reference to FIGS. 1 to 10.
As shown in FIGS. 1 to 3, the disc brake 1 includes a pair of inner brake pads 2 and an outer brake pad 3 arranged on both sides in the axial direction with the disc rotor D attached to the rotating portion of the vehicle interposed therebetween. , A caliper 4 is provided. The disc brake 1 is configured as a floating caliper type. The pair of inner brake pads 2, the 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. In the following description, for convenience of explanation, the right side of FIG. 1 will be referred to as one end side, and the left side will be appropriately described as the other end side.

As shown in FIGS. 1 to 3, the caliper main body 6 which is the main body of the caliper 4 has a cylinder portion 7 arranged on the base end side facing the inner brake pad 2 inside the vehicle and an outer brake pad on the outside of the vehicle. It has a claw portion 8 arranged on the tip side facing the 3. The cylinder portion 7 has a large-diameter opening 9A through which the inner brake pad 2 side is opened, and a bottomed cylinder 15 closed by a bottom wall 11 having a hole portion 10 on the opposite side thereof is formed. On the bottom wall 11 side in the cylinder 15, a small diameter opening 9B which is connected to the large diameter opening 9A and has a smaller diameter than the large diameter opening 9A is formed. The cylinder 15 has a piston seal 16 arranged on the inner peripheral surface of the large-diameter opening 9A.

With reference to FIGS. 6 and 7, the piston 18 is formed in the shape of a bottomed cup composed of a bottom portion 19 and a cylindrical portion 20. The piston 18 is housed in a cylinder 15 so that its bottom 19 faces the inner brake pad 2. The piston 18 is housed in the large-diameter opening 9A of the cylinder 15 so as to be movable in the axial direction while in contact with the piston seal 16. The space between the piston 18 and the bottom wall 11 of the cylinder 15 is defined by a piston seal 16 as a hydraulic chamber 21. The hydraulic pressure chamber 21 is supplied with hydraulic pressure from a hydraulic pressure source (not shown) such as a master cylinder or a hydraulic pressure control unit through a port (not shown) provided in the cylinder portion 7.

A plurality of rotation restricting vertical grooves 22 are formed on the inner peripheral surface of the piston 18 along the circumferential direction. A recess 25 is provided on the outer peripheral side of the other end surface of the bottom 19 of the piston 18 facing the inner brake pad 2. The concave portion 25 is engaged with the convex portion 26 formed on the back surface of the inner brake pad 2. By this engagement, the piston 18 is restricted to be non-rotatable relative to the cylinder 15 and thus the caliper body 6. Further, a dust boot 27 for preventing foreign matter from entering the cylinder 15 is interposed between the outer peripheral surface of the piston 18 on the bottom 19 side and the inner peripheral surface of the large-diameter opening 9A of the cylinder 15. There is.

As shown in FIGS. 1 to 3, a housing 30 in which the motor gear assembly 29 is housed is attached to the bottom wall 11 side of the cylinder 15 of the caliper main body 6. An opening 30A is provided at one end of the housing 30. The opening 30A of the housing 30 is airtightly closed by the cover 36. A seal member 37 is provided between the housing 30 and the cylinder portion 7. The inside of the housing 30 is maintained in airtightness by the sealing member 37. The housing 30 is integrated with the first housing portion 31 for accommodating the spur tooth multi-stage deceleration mechanism 44 and the planetary gear deceleration mechanism 45, which will be described later, so as to cover the outer periphery of the bottom wall 11 of the cylinder 15. It is composed of a second housing portion 32, which is projected in a bottomed cylindrical shape and accommodates the electric motor 200. As described above, the housing 30 is configured by the bottomed cylindrical second housing portion 32 to accommodate the electric motor 200 arranged so as to be aligned with the caliper main body 6.

The first housing portion 31 includes an outer wall portion 31F and a bottom surface portion 31G that surround the accommodation chamber 31E accommodating the spur tooth multi-stage deceleration mechanism 44 and the planetary gear deceleration mechanism 45, which will be described later, together with the cover 36, and a part of the bottom wall 11 of the cylinder 15. 31A for mounting, and a mounting opening 31A through which the polygonal shaft portion 81 of the base nut 75 of the rotary linear motion conversion mechanism 43 described later is inserted, and one end side (cover 36 side) around the mounting opening 31A. The inner annular wall portion 31B, the outer annular wall portion 31C arranged at a distance outward in the radial direction from the inner annular wall portion 31B and projecting to one end side, and the outer annular wall portion 31C spaced apart from each other in the circumferential direction. It has a plurality of engaging grooves 31D formed by placing the above.

The caliper main body 6 has a spur tooth multi-stage deceleration mechanism 44 and a planetary gear deceleration mechanism 45 for enhancing the driving force of the electric motor 200, and a piston propulsion mechanism for propelling the piston 18 and holding the propelled piston 18 at a braking position. The rotary linear motion conversion mechanism 43 of the above is provided. The spur tooth multi-stage deceleration mechanism 44 and the planetary gear deceleration mechanism 45 as deceleration mechanisms are housed in a storage chamber 31E inside the first housing portion 31 of the housing 30.

The spur tooth multi-stage reduction mechanism 44 has a pinion gear 46, a first reduction gear 47, and a non-reduction spur gear 48. The pinion gear 46 is made of metal, and the first reduction gear 47 and the non-reduction spur gear 48 are made of resin such as fiber reinforced resin. The pinion gear 46 has a hole 50 formed in a cylindrical shape and press-fitted and fixed to the rotating shaft 201 of the electric motor 200, and a gear 51 formed on the outer periphery thereof. The first reduction gear 47 is formed with a shaft hole 47A extending in the axial direction at the center thereof in the radial direction. The first reduction gear 47 is integrally formed with a large-diameter large gear 53 that meshes with the gear 51 of the pinion gear 46 and a small-diameter small gear 54 that extends concentrically from the large gear 53 in the axial direction. There is.

The shaft 52 is integrally fixed to the shaft hole 47A of the first reduction gear 47. One end of the shaft 52 is rotatably supported by a support plate 59 close to the cover 36, and the other end is rotatably supported by a holder 205. The small gear 54 of the first reduction gear 47 meshes with the non-reduction spur gear 48. The non-reducing spur gear 48 is rotatably supported by a shaft 55. One end of the shaft 55 is press-fitted and fixed to a support plate 59 close to the cover 36, and the other end is rotatably supported by the holder 205.

The planetary gear reduction mechanism 45 includes a second reduction gear 49 having a sun gear 57, a plurality of (four in this embodiment) planetary gears 60, an internal gear 61, and a carrier 62. With reference to FIGS. 4 and 5, the second reduction gear 49 meshes with the non-reduction spur gear 48 and has a large diameter large gear 56 having an annular wall portion 39 and a shaft concentrically from the large gear 56. It is composed of a sun gear 57 having a small diameter extending in the direction and a sun gear 57 having a small diameter. The large gear 56 corresponds to a large diameter gear, and the sun gear 57 corresponds to a small diameter gear. These large gears 56 and sun gears 57 are configured as separate bodies. The large gear 56 is integrally provided with an annular wall portion 39 on one end side thereof. The large gear 56 is made of a resin such as a fiber reinforced resin. At the radial center of the large gear 56, a hole 40 having a substantially circular shape in a plan view is formed inside the annular wall portion 39. A plurality of locking groove portions 40A are formed at equal intervals along the circumferential direction on the inner peripheral surface of the annular wall portion 39. In the present embodiment, the locking groove portions 40A are formed at four locations. The locking groove portion 40A is formed in a U-shape in a plan view. The plan view shape of the hole portion 40 including the locking groove portion 40A is point-symmetrical with respect to the radial center thereof. On one end surface of the annular wall portion 39, an annular protrusion 41 projecting from one end side is formed around the hole portion 40 including each locking groove portion 40A. As a matter of course, in the annular wall portion 39, the range of the protrusion 41 is thicker than the other portions.

The sun gear 57 is integrally integrated with the fitting portion 57A having a substantially circular shape in a plan view, which is fitted into the hole 40 of the large gear 56, concentrically from the radial center portion of the fitting portion 57A in the axial direction. It is provided with a gear portion 57B extending to. The sun gear 57 is entirely made of metal. The sun gear 57 may have at least the gear portion 57B made of metal. The fitting portion 57A is formed to have a larger diameter than the gear portion 57B. The fitting portion 57A has an outer diameter that can be fitted so as to be in contact with each other in the hole portion 40 of the large gear 56. The sun gear 57 is provided with a shaft hole 49A through which the shaft 58 is inserted in the radial center thereof along the axial direction. On the outer peripheral surface of the fitting portion 57A, a locking piece 57C corresponding to each locking groove portion 40A provided in the hole portion 40 of the large gear 56 is projected outward in the radial direction. The thickness of each locking piece 57C of the sun gear 57 is substantially the same as the thickness of the protrusion 41 around the hole 40 of the large gear 56. On one end surface of the fitting portion 57A, a recess 57D having a substantially circular shape in a plan view is formed around the shaft hole 49A.

Then, the fitting portion 57A of the sun gear 57 is tightly fitted into the hole 40 of the large gear 56, and each locking piece 57C provided in the fitting portion 57A is locked in the hole 40. It is tightly engaged with the groove 40A. As a result, as the second reduction gear 49, the large gear 56 and the sun gear 57 are integrally connected so as not to rotate relative to each other. Each of the locking groove portions 40A provided in the hole 40 of the large gear 56 and each locking piece 57C provided in the fitting portion 57A of the sun gear 57 are relative to regulate the relative rotation of the large gear 56 and the sun gear 57. Functions as a rotation control unit. As shown in FIG. 2, the shaft 58 is press-fitted and fixed to a support plate 59 having one end close to the cover 36. The shaft 58 is rotatably inserted into the shaft hole 49A of the sun gear 57. As a result, the sun gear 57 and, by extension, the second reduction gear 49 are rotatably supported by the shaft 58.

As shown in FIGS. 1 to 3, each planetary gear 60 is made of a resin such as a fiber reinforced resin. Each planetary gear 60 may be made of metal depending on the magnitude of the rotational torque from the electric motor 200. The planetary gear 60 has a gear 63 that is meshed with a gear portion 57B of the sun gear 57 of the second reduction gear 49, and a pin hole portion 64 through which a pin 65 erected from the carrier 62 is rotatably inserted. ing. The planetary gears 60 are arranged at equal intervals on the circumference of the carrier 62. As will be described later, the movement of each planetary gear 60 in the axial direction is restricted between the annular wall portion 72 of the internal gear 61 and the annular plate 66. The sun gear 57 of the second reduction gear 49 is restricted from moving in the axial direction between the support plate 59 and each planetary gear 60.

The carrier 62 is made of metal. The carrier 62 is formed in a disk shape, and a polygonal hole 68 is formed substantially in the center in the radial direction. The outer diameter of the carrier 62 is substantially the same as the outer diameter of the revolution trajectory of each planetary gear 60. A plurality of pin holes 69 are formed on the outer peripheral side of the carrier 62 at intervals along the circumferential direction. A pin 65 is press-fitted and fixed to each pin hole 69. Each pin 65 is rotatably inserted into a pin hole portion 64 of each planetary gear 60. Then, the polygonal hole 68 of the carrier 62 and the polygonal shaft portion 81 (see FIG. 7) of the base nut 75 of the rotational linear motion conversion mechanism 43, which will be described later, are fitted to the carrier 62 and the base nut 75. Rotational torque can be transmitted to each other.

The internal gear 61 is made of a resin such as a fiber reinforced resin. The internal gear 61 extends radially from one end of the internal tooth 71 on which the gear 63 of each planetary gear 60 is meshed and one end of the internal tooth 71 on the cover 36 side, and moves in the axial direction of each planetary gear 60. It includes an annular wall portion 72 for regulation, and a tubular wall portion 73 extending from the internal teeth 71 toward the bottom wall 11 of the cylinder 15. A plurality of protrusions 74 are formed on the outer peripheral surface of the tubular wall portion 73 of the internal gear 61 at intervals in the circumferential direction. Each of the protrusions 74 projects radially outward. Then, the tubular wall portion 73 of the internal gear 61 is inserted into the annular space between the inner annular wall portion 31B and the outer annular wall portion 31C of the first housing portion 31, and each of the protrusions 74 thereof is an outer annular wall portion 74. By being inserted and engaged with each engaging groove 31D provided in the wall portion 31C, it is supported in the first housing portion 31 so as to be relatively non-rotatable. Further, the internal gear 61 cannot move in the axial direction because the annular stopper portion 39A provided on the large gear 56 of the second reduction gear 49 comes into contact with the cover 36 side of the annular wall portion 72. 1 It is supported in the housing portion 31.

Further, the annular plate 66 is arranged inside the other end side of the internal teeth 71 of the internal gear 61. The annular plate 66 is sandwiched between the end surface of the internal teeth 71 of the internal gear 61 and the inner annular wall portion 31B of the first housing portion 31. As a result, each planetary gear 60 is arranged between the annular wall portion 72 of the internal gear 61 and the annular plate 66, and its axial movement is restricted.

The electric motor 200 is supported by a holder 205 arranged on its flange portion 202. The holder 205 is configured by integrally connecting the motor support portion 206 and the ring-shaped support portion 207. The motor support portion 206 is arranged between the first reduction gear 47 and the non-reduction spur gear 48 and the flange portion 202 of the electric motor 200 to support the electric motor 200. The ring-shaped support portion 207 is arranged around the internal gear 61 of the planetary gear reduction mechanism 45 so as to surround the internal gear 61. As can be seen from FIG. 2, the motor support portion 206 is formed with a rotary shaft insertion hole 208 through which a pinion gear 46 press-fitted and fixed to the rotary shaft 201 of the electric motor 200 is inserted. Two terminal insertion holes through which the motor terminals 203 of the electric motor 200 are inserted are formed around the rotation shaft insertion holes 208. A pair of insertion holes for each terminal is formed on both sides in the radial direction of the insertion holes 208 for the rotating shaft. Harnesses 250 and 251 are connected to each motor terminal 203 of the electric motor 200, respectively.

The motor support portion 206 of the holder 205 has a holder-side first convex portion 211, a holder-side second convex portion 212, and a holder-side second on the side opposite to the planetary gear reduction mechanism 45 side around the rotation shaft insertion hole 208. The three convex portions 213 are formed at intervals from each other. The holder-side first convex portion 211, the holder-side second convex portion 212, and the holder-side third convex portion 213 are cylindrical and project to the cover 36 side. Two fastening holes 216 are formed in the motor support portion 206. Each mounting bolt 215 is fastened to the fastening hole 216 of the motor support portion 206 via each through hole 202A of the flange portion 202 of the electric motor 200, and the electric motor 200 is supported by the motor support portion 206 of the holder 205. .. The ring-shaped support portion 207 is arranged on each protrusion 74 so as to abut on the outer peripheral surface of the internal gear 61 of the planetary gear reduction mechanism 45.

Cylindrical support portions 217 and 217 are integrally formed in the holder 205 at two locations at intervals between the motor support portion 206 and the ring-shaped support portion 207. A support plate 59 is arranged on each cylindrical support portion 217. Then, each mounting bolt 218 is fastened to each cylindrical support portion 217 of the holder 205 via the support plate 59, so that the support plate 59 is supported on the holder 205 at intervals.

As can be seen from FIG. 3, the cover-side first cylindrical portion 221 and the cover-side second convex portion 222 and the cover-side third convex portion 223 are respectively projected on the inner surface of the cover 36 at intervals. The cover-side first cylindrical portion 221 and the cover-side second convex portion 222 and the cover-side third convex portion 223 are the holder-side first convex portion 211, the holder-side second convex portion 212, and the holder-side provided in the holder 205. It is formed at a position facing the third convex portion 213. Then, the cover-side first cylindrical portion 221 and the cover-side second convex portion 222 and the cover-side third convex portion 223 of the cover 36, and the holder-side first convex portion 211 and the holder-side second convex portion of the holder 205. A rubber 230, which is an elastic member, is interposed between the 212 and the third convex portion 213 on the holder side. The rubber 230 integrates the first cup portion 231 and the second cup portion 232, the third cup portion 233, and the opening side ends of the first cup portion 231 and the second cup portion 232 and the third cup portion 233. It is composed of a plate-shaped base portion 234 to be connected to the target.

Then, the first cup portion 231 of the rubber 230 is fitted to the holder-side first convex portion 211 of the holder 205, and the second cup portion 232 of the rubber 230 is fitted to the holder-side second convex portion 212 of the holder 205. Then, the third cup portion 233 of the rubber 230 is fitted to the holder-side third convex portion 213 of the holder 205, and the rubber 230 is unitized in the holder 205. After that, the cover-side first cylindrical portion 221 of the cover 36 is fitted to the first cup portion 231 of the rubber 230, and the cover-side second convex portion 222 of the cover 36 is fitted to the second cup portion 232 of the rubber 230. The cover 36 is covered with the cover 36 so that the third convex portion 223 on the cover side of the cover 36 comes into contact with the third cup portion 233 of the rubber 230. Further, harnesses 250 and 251 extending from each motor terminal 203 of the electric motor 200 are arranged along the base portion 234 of the rubber 230.

As shown in FIG. 2, in the present embodiment, a plurality of types of rubbers 281, 282, and 283 different from the rubber 230 described above are provided in the housing 30. A cross-section U-shaped support portion 280 is formed at the end of the holder 205 on the motor support portion 206 side, and the cross-section U-shaped rubber 281 is integrally arranged inside the cross-section U-shaped support portion 280. In the ring-shaped support portion 207 of the holder 205, the block-shaped rubber 282 is arranged between the outer peripheral surface at a position close to each cylindrical support portion 217 and the inner wall surface of the first housing portion 31. A cylindrical rubber 283 is arranged between the main body side end portion of the electric motor 200 and the bottom wall portion of the second housing portion 32. In this way, the electric motor 200, the spur tooth multi-stage deceleration mechanism 44, the planetary gear deceleration mechanism 45, and the rubbers 230, 281, 28, 283 are assembled to the holder 205 and the support plate 59 to form the motor gear assembly 29. The motor gear assembly 29 is attached to the housing 30 and the cover 36 in a suspended state, that is, in a so-called floating state, by means of rubbers 230, 281, 28, 283.

In the present embodiment, in order to obtain the rotational force for propelling the piston 25, the spur tooth multi-stage deceleration mechanism 44 and the planetary gear deceleration mechanism 45 are adopted as the deceleration mechanism for increasing the driving force by the electric motor 200. It may be configured only by the gear reduction mechanism 45. Further, a speed reducer according to another known technique such as a cycloid speed reduction mechanism or a wave speed reducer may be combined with the planetary gear speed reduction mechanism 45.

Next, the rotation linear motion conversion mechanism 43 as the piston propulsion mechanism will be specifically described with reference to FIGS. 1, 6, and 7. In the following description, for convenience of explanation, the right side of FIGS. 1 and 6 will be referred to as one end side, and the left side will be appropriately described as the other end side.
The rotary linear motion conversion mechanism 43 converts the rotational motion from the spur tooth multi-stage deceleration mechanism 44 and the planetary gear deceleration mechanism 45, that is, the rotation of the electric motor 200 into linear motion (hereinafter, referred to as linear motion for convenience). A thrust force is applied to the piston 18 to hold the piston 18 at the braking position. The rotary linear motion conversion mechanism 43 is screwed to a base nut 75 that is rotatably supported by transmitting rotational motion from the spur tooth multi-stage deceleration mechanism 44 and the planetary gear deceleration mechanism 45, and a female thread portion 97 of the base nut 75. A push rod 102 that is fitted and is rotatably and linearly supported by the rotation of the base nut 75, and is screw-fitted to the push rod 102 and axially toward the piston 18 by the rotation of the push rod 102. It is equipped with a ball-and-ramp mechanism 127 that imparts a thrust to the head. The rotary linear motion conversion mechanism 43 is housed between the bottom wall 11 of the cylinder 15 of the caliper main body 6 and the piston 18.

The base nut 75 is composed of a columnar portion 76 and a nut portion 77 integrally provided at the other end of the columnar portion 76. A washer 80 is arranged so as to abut on the bottom wall 11 of the cylinder 15. The columnar portion 76 of the base nut 75 is inserted into the insertion hole 80A of the washer 80 and the hole portion 10 provided in the bottom wall 11 of the cylinder 15. A polygonal shaft portion 81 is integrally connected to the tip of the cylindrical portion 76. The polygonal shaft portion 81 is fitted into the polygonal hole 68 of the carrier 62 through the mounting opening 31A of the first housing portion 31. The nut portion 77 of the base nut 75 is formed in a bottomed cylindrical shape. The nut portion 77 is composed of a circular wall portion 82 and a cylindrical portion 83 integrally and concentrically projecting from the other end surface of the circular wall portion 82. The outer peripheral surface of the circular wall portion 82 is close to the inner wall surface of the small diameter opening 9B of the cylinder 15. The small-diameter circular wall portion 84 is concentrically projected from the radial center portion of one end surface of the circular wall portion 82. A columnar portion 76 is projected concentrically from one end surface of the small-diameter circular wall portion 84 toward one end side. The outer diameter of the cylindrical portion 76 is formed to be smaller than the outer diameter of the cylindrical portion 83 of the nut portion 77.

A thrust bearing 87 is arranged between the washer 80 and the circular wall portion 82 around the small diameter circular wall portion 84 provided in the nut portion 77 of the base nut 75. The base nut 75 is rotatably supported by the bottom wall 11 of the cylinder 15 by the thrust bearing 87. A seal member 88 and a sleeve 89 are provided between the outer peripheral surface of the columnar portion 76 of the base nut 75 and the hole portion 10 of the bottom wall 11 of the cylinder 15, respectively. As a result, the liquidtightness of the hydraulic chamber 21 is maintained. A retaining ring 90 is mounted in an annular groove provided between the columnar portion 76 of the base nut 75 and the polygonal shaft portion 81. The retaining ring 90 restricts the movement of the base nut 75 in the axial direction.

The cylindrical portion 83 of the nut portion 77 of the base nut 75 is composed of a large-diameter cylindrical portion 91 arranged on one end side and a small-diameter cylindrical portion 92 arranged on the other end side. One end of the large-diameter cylindrical portion 91 is integrally connected to the circular wall portion 82. A plurality of radial through holes 95 are formed in the peripheral wall portion of the large-diameter cylindrical portion 91. A plurality of through holes 95 are formed at intervals in the circumferential direction. A female screw portion 97 is formed on the inner peripheral surface of the small-diameter cylindrical portion 92 of the nut portion 77. A plurality of locking grooves 98 are formed on the other end surface of the peripheral wall portion of the small-diameter cylindrical portion 92 at intervals in the circumferential direction. In this embodiment, the locking grooves 98 are formed at four locations.

The tip portion 100A of the first spring clutch 100, which imparts rotational resistance to rotation in one direction, is fitted into any of the locking grooves 98 of the small-diameter cylindrical portion 92 of the base nut 75. The first spring clutch 100 is composed of a tip portion 100A facing outward in the radial direction and a coil portion 100B continuously and singlely wound from the tip portion 100. Then, the tip portion 100A of the first spring clutch 100 is fitted into any of the locking grooves 98 of the small-diameter cylindrical portion 92 of the base nut 75, and the coil portion 100B is the male screw portion 103 of the push rod 102 described later. Wrapped around the other end. The first spring clutch 100 applies rotational resistance torque to the base nut 75 in the rotational direction (rotational direction at the time of release) when the push rod 102 moves toward the bottom wall 11 side of the cylinder 15. The push rod 102 is configured to allow rotation in the rotation direction (rotation direction at the time of application) when the push rod 102 moves toward the bottom 19 side of the piston 18 with respect to the base nut 75.

One end side of the push rod 102 is inserted into the nut portion 77 of the base nut 75. On one end side of the push rod 102, a male threaded portion 103 that is screw-fitted to the female threaded portion 97 of the small-diameter cylindrical portion 92 of the base nut 75 is formed. The first thread fitting portion 105 between the male threaded portion 103 of the push rod 102 and the female threaded portion 97 of the small diameter cylindrical portion 92 of the base nut 75 is a base nut due to an axial load from the piston 18 to the push rod 102. It is configured as a screw fitting portion having a large irreversibility so that the reverse efficiency of the 75 does not rotate and its reverse efficiency becomes 0 or less.

On the other hand, on the other end side of the push rod 102, a male screw portion 104 that is screw-fitted to the female screw portion 162 provided in the rotary linear motion lamp 151 of the ball and lamp mechanism 127, which will be described later, is formed. Again, the second thread fitting portion 106 between the male threaded portion 104 of the push rod 102 and the female threaded portion 162 provided on the rotary linear motion lamp 151 is an axial load from the piston 18 to the rotary linear motion lamp 151. The push rod 102 is configured to have a reverse efficiency of 0 or less so that the push rod 102 does not rotate, that is, as a screw fitting portion having a large irreversible property.

The push rod 102 is provided with a spline shaft 108 between the male threaded portion 103 on one end side and the male threaded portion 104 on the other end side. The outer diameter of the male threaded portion 103 on one end side is formed to be larger than the outer diameter of the male threaded portion 104 on the other end side. The outer diameter of the male threaded portion 103 on one end side is formed to be larger than the outer diameter of the spline shaft 108. A small-diameter cylindrical portion 107 is continuously formed on the other end side of the male screw portion 104 of the push rod 102. The outer peripheral surface of the cylindrical portion 107 is knurled. The stopper member 172 is integrally fixed to the cylindrical portion 107 of the push rod 102 by press fitting. The stopper member 172 determines the relative rotation range of the rotary linear motion lamp 151 with respect to the push rod 102. The other end surface of the cylindrical portion 107 of the push rod 102 faces the bottom portion 19 of the piston 18.

The retainer 110 is movably supported in the axial direction between the outer peripheral surface of the small-diameter cylindrical portion 92 of the cylindrical portion 84 constituting the nut portion 77 of the base nut 75 and the inner peripheral surface of the cylindrical portion 20 of the piston 18. .. The retainer 110 has an annular wall portion 111 on one end side, and is configured to have a substantially cylindrical shape as a whole. A plurality of through holes 114 and 115 are formed on the outer peripheral wall of the retainer 110.

In the retainer 110, in order from one end side, one end side washer 120, coil spring 121, other end side washer 122, support plate 123, second spring clutch 124, rotating member 125, thrust bearing 126, ball and lamp mechanism 127, A thrust bearing 128 and an annular pressing plate 129 are arranged. The one-end side washer 120 is arranged so as to abut on the other end surface of the annular wall portion 111 of the retainer 110.

A coil spring 121 is interposed between the washer 120 on the one end side and the washer 122 on the other end side. The coil spring 121 is urged in a direction in which the washer 120 on the one end side and the washer 122 on the other end side are separated from each other. A plurality of locking grooves 132 having a predetermined depth are formed on the other end surface of the peripheral wall portion of the retainer 110 at intervals in the circumferential direction. Each locking groove 132 is continuously composed of a narrow locking groove 133 located on one end side and a wide locking groove 134 located on the other end side. The locking grooves 132 are formed at three locations in this embodiment. At the other end of the retainer 110, a plurality of claw portions 136 toward the bottom portion 19 of the piston 18 are formed. In the retainer 110, one end side washer 120, coil spring 121, other end side washer 122, support plate 123, second spring clutch 124, rotating member 125, thrust bearing 126, ball and lamp mechanism 127, thrust bearing 128 and annular After accommodating the pressing plate 129, each claw portion 136 of the retainer 110 is folded toward the accommodating recess 171 of the annular pressing plate 129 described later, so that a large number of the above-mentioned constituent members are integrally arranged in the retainer 110. Can be made into an assembly.

The annular support plate 123 is arranged so as to abut on the other end surface of the other end side washer 122. A plurality of protrusion pieces 137 are provided on the outer peripheral surface of the support plate 123 at intervals along the circumferential direction. In this embodiment, the protrusion pieces 137 are formed at three positions. Each protrusion 137 of the support plate 123 is fitted into each narrow locking groove 133 of the retainer 110 and each rotation regulation vertical groove 22 provided on the inner peripheral surface of the piston 18. As a result, the retainer 110 is supported together with the washer 120 on one end side, the coil spring 121, the washer 122 on the other end side, and the support plate 123 so as to be relatively non-rotatable with respect to the piston 18 and relatively movable in the axial direction.

In the retainer 110, the rotating member 125 is rotatably supported on the other end side of the support plate 123. The rotating member 125 is composed of a large-diameter annular portion 141 having a spline hole 140 and a small-diameter cylindrical portion 142 integrally and concentrically projecting from one end surface of the large-diameter annular portion 141. One end of the small-diameter cylindrical portion 142 is in contact with the other end surface of the support plate 123. The push rod 102 is inserted into the rotating member 125, and the spline hole 140 of the large-diameter annular portion 141 of the rotating member 125 and the spline shaft 108 of the push rod 102 are spline-coupled. As a result, the rotational torque of the rotating member 125 and the push rod 102 can be transmitted to each other.

The second spring clutch 124 is wound around the outer peripheral surface of the small-diameter cylindrical portion 142 of the rotating member 125. Like the first spring clutch 100, the second spring clutch 124 is composed of a tip portion 124A facing outward in the radial direction and a coil portion 124B continuously and singlely wound from the tip portion 124A. .. Then, the tip portion 124A of the second spring clutch 124 is fitted into any of the narrow locking grooves 133 of the retainer 110, and the coil portion 124B is wound around the outer peripheral surface of the small-diameter cylindrical portion 142 of the rotating member 125. .. The second spring clutch 124 imparts rotational resistance torque to the rotation direction (rotation direction at the time of application) when the rotation member 125 (push rod 102) moves toward the bottom 19 side of the piston 18 with respect to the retainer 110. On the other hand, it is configured to allow rotation in the rotation direction (rotation direction at the time of release) when moving to the bottom wall 11 side of the cylinder 15.

The rotational resistance torque at the time of applying the second spring clutch 124 is larger than the rotational resistance torque of the first screw fitting portion 105 between the male thread portion 103 of the push rod 102 and the female thread portion 97 of the base nut 75. It is set to be large. A ball-and-ramp mechanism 127 is arranged on the other end side of the rotating member 125 via a thrust bearing 126. The rotating member 125 is rotatably supported by the ball-and-ramp mechanism 127 via a thrust bearing 126.

The ball-and-ramp mechanism 127 includes a fixed lamp 150, a rotary linear motion lamp 151, and each ball 152 interposed between the fixed lamp 150 and the rotary linear motion lamp 151. The fixed lamp 150 is arranged on the other end side of the rotating member 125 via the thrust bearing 126. The fixed lamp 150 is composed of a disk-shaped fixed plate 154 and a plurality of convex portions 155 projecting from the outer peripheral surface of the fixed plate 154 at intervals in the circumferential direction. In the present embodiment, the convex portions 155 are formed at three positions. An insertion hole 156 through which the push rod 102 is inserted is formed in the radial center portion of the fixing plate 154. Each of the convex portions 155 of the fixed lamp 150 is fitted into each wide locking groove 134 of the retainer 110 and also into each rotation restricting vertical groove 22 provided on the inner peripheral surface of the piston 18. It is supported so as to be non-rotatable relative to the piston 18 and movably movable in the axial direction. On the other end surface of the fixed plate 154, a plurality of ball grooves 157 having a predetermined inclination angle along the circumferential direction and extending in an arc shape and having an arcuate cross section in the radial direction, and three ball grooves 157 in the present embodiment are formed. ing.

The rotary linear motion lamp 151 is composed of an annular rotary linear motion plate 160 and a cylindrical portion 161 integrally projecting from the radial center portion of the other end surface of the rotary linear motion plate 160. On the inner peripheral surface from the rotary linear motion plate 160 to the cylindrical portion 161 is formed a female threaded portion 162 in which the male threaded portion 104 of the push rod 102 is screw-fitted. A plurality of rotary linear motion plates 160 extending in an arc shape having a predetermined inclination angle along the circumferential direction and having an arc shape cross section in the radial direction on the facing surface of the fixed lamp 150 with the fixed plate 154. In the embodiment, three ball grooves 163 are formed.

The ball 152 is interposed between each ball groove 163 of the rotary linear motion lamp 151 (rotary linear motion plate 160) and each ball groove 157 of the fixed lamp 150 (fixed plate 154). Then, when a rotational torque is applied to the rotary linear motion lamp 151, each ball 152 between each ball groove 163 of the rotary linear motion plate 160 and each ball groove 157 of the fixed plate 154 rolls, thereby rotating the rotary linear motion. The rotational difference between the plate 160 and the fixed plate 154 causes the relative distance in the axial direction between the rotary linear motion plate 160 and the fixed plate 154 to fluctuate.

An annular pressing plate 129 is arranged on the other end surface of the rotary linear motion plate 160 around the cylindrical portion 161 via a thrust bearing 128. A plurality of convex portions 168 are projected on the outer peripheral surface of the annular pressing plate 129 at intervals along the circumferential direction. In this embodiment, the convex portions 168 are formed at three positions. Each of the convex portions 168 of the annular pressing plate 129 is fitted into each wide locking groove 134 of the retainer 110 and also into each rotation restricting vertical groove 22 provided on the inner peripheral surface of the piston 18. It is supported so as to be non-rotatable relative to the piston 18 and movably movable in the axial direction.

The rotary direct-acting lamp 151 of the ball-and-ramp mechanism 127 is rotatably supported by an annular pressing plate 129 via a thrust bearing 128. The other end surface of the annular pressing plate 129 comes into contact with the bottom portion 19 of the piston 18 to press the piston 18. On the other end surface of the annular pressing plate 129, a storage recess 171 for accommodating each inwardly folded claw portion 136 of the retainer 110 is formed on the outer peripheral portion between the convex portions 168.

Further, as shown in FIG. 1, an ECU 175 that drives and controls the electric motor 200 is electrically connected to the electric motor 200 via harnesses 250 and 251. A parking switch 176, which is operated to indicate the operation / release of the parking brake, is connected to the ECU 175. Further, the ECU 175 can be operated without operating the parking switch 176 based on a signal from the vehicle side (not shown).

Next, the operation of the disc brake 1 according to the present embodiment will be described.
First, the operation of the disc brake 1 as a normal hydraulic brake by operating the brake pedal (not shown) during braking will be described.
When the brake pedal is depressed by the driver, hydraulic pressure corresponding to the pedaling force of the brake pedal is supplied from the master cylinder to the hydraulic chamber 21 in the caliper 4 via a hydraulic pressure circuit (both not shown). As a result, the piston 18 moves forward (moves to the left in FIG. 1) from the original position during non-braking while elastically deforming the piston seal 16, and presses the inner brake pad 2 against the disc rotor D. Then, the caliper main body 6 moves to the right in FIG. 1 with respect to the bracket 5 by the reaction force of the pressing force of the piston 18, and presses the outer brake pad 3 against the disc rotor D by the claw portion 8. As a result, the disc rotor D is sandwiched between the pair of inners and the outer brake pads 2 and 3, and a frictional force is generated, which in turn generates a braking force of the vehicle.

Then, when the driver releases the brake pedal, the supply of the hydraulic pressure from the master cylinder is cut off, and the hydraulic pressure in the hydraulic pressure chamber 21 drops. As a result, the piston 18 is retracted to the original position by the restoring force of the elastic deformation of the piston seal 16, and the braking force is released. Incidentally, when the amount of movement of the piston 18 increases with the wear of the inner and outer brake pads 2 and 3 and exceeds the limit of elastic deformation of the piston seal 16, slippage occurs between the piston 18 and the piston seal 16. Due to this slip, the original position of the piston 18 with respect to the caliper body 6 moves, and the pad clearance is adjusted to be constant.

Next, the action as a parking brake, which is an example of the action for maintaining the stopped state of the vehicle, will be described.
First, when the parking switch 176 is operated from the released state of the parking brake to operate (apply) the parking brake, the electric motor 200 is driven by the signal from the ECU 175 to drive the planet via the flat tooth multi-stage deceleration mechanism 44. The sun gear 57 of the gear reduction mechanism 45 is rotated. The rotation of the sun gear 57 causes the carrier 62 to rotate via each planetary gear 60. Then, the rotation from the carrier 62 is transmitted to the base nut 75.

Next, due to the rotation of the base nut 75 in the apply direction, the first screw fitting portion 105 rotates relatively, that is, only the base nut 75 rotates in the apply direction, while the push rod 102 rotates along the axial direction. It advances toward the bottom 19 side of the piston 18. This is because the rotational resistance torque of the rotating member 125 (push rod 102) with respect to the retainer 110 (piston 18) by the second spring clutch 124 in the apply direction is the first screw fitting between the push rod 102 and the base nut 75. This is because the torque is set to be larger than the rotational resistance torque of the joint portion 105, and the push rod 102 is allowed to rotate in the apply direction with respect to the base nut 75 by the first spring clutch 100.

As a result, one end side washer 120, coil spring 121, other end side washer 122, support plate 123, second spring clutch 124, rotating member 125, thrust bearing 126, ball and Each component of the lamp mechanism 127, the thrust bearing 128, and the annular pressing plate 129 is integrally advanced toward the bottom 19 side of the piston 18 along the axial direction. By advancing these components, the annular pressing plate 129 abuts on the bottom 19 of the piston 18, the piston 18 advances, and one end surface of the bottom 19 of the piston 18 abuts on the inner brake pad 2.

Further, when the rotational drive of the electric motor 200 in the apply direction is continued, the piston 18 starts pressing the disc rotor D via the inner and outer brake pads 2 and 3 by the movement of the push rod 102. When this pressing force begins to be generated, the rotational resistance torque in the first screw fitting portion 105 between the push rod 102 and the base nut 75 increases due to the axial force that becomes a reaction force to the pressing force. Therefore, it becomes larger than the rotational resistance torque of the second spring clutch 124. As a result, the push rod 102 starts to rotate in the apply direction together with the rotating member 125 as the base nut 75 rotates. Then, due to the reaction force from the pressing force of the disc rotor D, the rotational resistance torque in the second screw fitting portion 106 between the push rod 102 and the ball and lamp mechanism 127 also increases due to the reaction force of the pressing force of the disc rotor D. Therefore, the rotational torque of the push rod 102 in the apply direction is transmitted to the rotary linear motion lamp 151 of the ball and lamp mechanism 127 via the second screw fitting portion 106.

At this time, the rotational torque of the push rod 102 in the apply direction causes a relative rotation difference (rotational linear motion lamp 151 rotates slightly later than the push rod 102) at the second screw fitting portion 106. , Is transmitted to the rotary linear motion lamp 151 of the ball and lamp mechanism 127. Then, each ball 152 rolls while the rotary linear motion lamp 151 of the ball and lamp mechanism 127 rotates in the apply direction, and the rotary linear motion lamp 151 and the fixed lamp 150 resist the urging force of the coil spring 121. The annular pressing plate 129 further presses the bottom 19 of the piston 18 by separating them from each other. As a result, the pressing force on the disc rotor D by the inner and outer brake pads 2 and 3 increases.

In the disc brake 1 according to the present embodiment, first, the first screw fitting portion 105 between the push rod 102 and the base nut 75 rotates relative to each other, the push rod 102 advances, and the piston 18 is moved. It is advanced to obtain a pressing force on the disc rotor D. Therefore, by operating the first screw fitting portion 105, the in-situ position of the push rod 102 with respect to the piston 18 that changes due to wear of the inner and outer brake pads 2 and 3 over time can be adjusted.

Then, the ECU 175 drives the electric motor 200 until the pressing force from the pair of inner and outer brake pads 2 and 3 to the disc rotor D reaches a predetermined value, for example, until the current value of the electric motor 200 reaches a predetermined value. do. After that, when the ECU 175 detects that the pressing force on the disc rotor D has reached a predetermined value when the current value of the electric motor 200 reaches a predetermined value, the ECU 175 stops energizing the electric motor 200. Then, the linear motion accompanying the rotation of the rotary linear motion lamp 151 of the ball and lamp mechanism 127 is stopped.

Finally, the reaction force of the pressing force from the disc rotor D acts on the rotary linear motion lamp 151, but the second screw fitting portion 106 between the push rod 102 and the ball and lamp mechanism 127 The first screw fitting portion 105 between the push rod 102 and the base nut 75 is also configured as a screw fitting portion that does not reversely operate with each other, and further comprises a screw fitting portion that does not reverse with each other. The first spring clutch 100 applies a rotational resistance torque to the base nut 75 in the release direction to the push rod 102, so that the piston 18 is held at the braking position. As a result, the braking force is maintained and the operation of the parking brake is completed.

Next, when the parking brake is released (released), the electric motor 200 is rotationally driven by the ECU 175 in the release direction to separate the piston 18 from the disc rotor D, based on the parking release operation of the parking switch 176. As a result, the spur tooth multi-stage deceleration mechanism 44 and the planetary gear deceleration mechanism 45 are rotationally driven in the release direction for returning the piston 18, and the rotational drive in the release direction is transmitted to the base nut 75 via the carrier 62.

At the time of this release, the reaction force of the pressing force from the disc rotor D acts on the push rod 102, in other words, the push rod 102 has a second position between the push rod 102 and the ball and lamp mechanism 127. The rotational resistance torque of the screw fitting portion 106, the rotational resistance torque of the first screw fitting portion 105 between the push rod 102 and the base nut 75, and the base nut of the push rod 102 by the first spring clutch 100. A rotational resistance torque in the release direction with respect to 75 is applied. Therefore, the rotational torque in the release direction from the base nut 75 is transmitted to the push rod 102 (including the rotary member 125) and also to the rotary linear motion lamp 151 of the ball and lamp mechanism 127. As a result, the rotary linear motion lamp 151 only rotates in the release direction and returns to the initial position in the rotational direction.

Next, the reaction force to the push rod 102 is reduced, and the rotational resistance torque of the second screw fitting portion 106 between the push rod 102 and the ball and lamp mechanism 127 is reduced by the base nut by the first spring clutch 100. It becomes smaller than the rotation resistance obtained by adding the rotation resistance torque of the first screw fitting portion 105 between the push rod 102 and the base nut 75 to the rotation resistance torque of the push rod 102 in the release direction with respect to the 75. Since the dynamic lamp 151 cannot rotate in the release direction any more, only the second screw fitting portion 106 rotates relative to each other, and the rotary linear motion lamp 151 of the ball and lamp mechanism 127 is along the axial direction together with the retainer 110. It moves to the bottom wall 11 side (release direction) of the cylinder 15 and returns to the initial position in the axial direction.

Further, when the electric motor 200 is rotationally driven in the release direction and the rotation of the base nut 75 in the release direction is continued, the rotary linear motion lamp 151 of the ball and lamp mechanism 127 is pushed while returning to the initial position in the axial direction. The second screw fitting portion 106 between the rod 102 and the ball-and-ramp mechanism 127 returns to the initial screwing position, and the rotation of the push rod 102 in the release direction is stopped.

Further, when the rotation of the base nut 75 in the release direction is continued, the push rod 102 is axially opposed to the rotational resistance torque of the push rod 102 in the release direction with respect to the base nut 75 by the first spring clutch 100. Along the same direction, the cylinder 15 retracts toward the bottom wall 11 side (release direction). As a result, one end side washer 120, coil spring 121, other end side washer 122, support plate 123, second spring clutch 124, rotating member 125, thrust bearing 126, ball and Each component of the lamp mechanism 127, the thrust bearing 128, and the annular pressing plate 129 is integrated and retracts along the axial direction toward the bottom wall 11 side (release direction) of the cylinder 15. Then, the piston 18 recedes to the original position due to the restoring force of the elastic deformation of the piston seal 16, and the braking force is completely released.

As described above, in the disc brake 1 according to the present embodiment, in particular, in the second reduction gear 49 of the planetary gear reduction mechanism 45, the large gear 56 and the sun gear 57 are configured as separate bodies, and these large gears are formed separately. The 56 and the sun gear 57 are connected so as not to rotate relative to each other. As a result, in advancing the metallization of the sun gear 57, insert molding becomes unnecessary, and it is possible to suppress the increase in size of the second reduction gear 49 along the axial direction due to insert molding. Moreover, it is possible to suppress inconveniences due to insert molding, for example, an increase in man-hours for installing insert parts in the resin mold, and concerns about damage to the metal gear when the metal gear is set in the resin mold. Moreover, since the large gear 56 and the sun gear 57 are formed separately, the relative position accuracy between the large gear 56 and the sun gear 57 can be ensured, and cost increase can be suppressed.

Further, in the disc brake 1 according to the present embodiment, the large gear 56 of the second reduction gear 49 is provided with a hole 40, and the sun gear 57 is provided with a fitting portion 57A fitted to the hole 40 of the large gear 56. A relative rotation restricting portion is formed between the hole 40 of the large gear 56 and the fitting portion 57A of the sun gear 57, and the relative rotation restricting portion is each locking groove portion 40A provided in the hole 40 of the large gear 56. And each locking piece 57C provided in the fitting portion 57A of the sun gear 57. As a result, the rotation from the large gear 56 can be smoothly transmitted to the sun gear 57 with a simple configuration.
Further, in the disc brake 1 according to the present embodiment, the annular wall portion 39 of the large gear 56 is provided with an annular protrusion 41 around the hole 40 including the locking groove 40A, and the periphery of the hole 40 is provided. Is formed thicker than other parts. As a result, the strength around the hole portion 40 can be increased, and when the rotation from the large gear 56 is transmitted to the sun gear 57, the locking groove portion 40A of the large gear 56 interferes with the locking piece 57C of the sun gear 57. Damage to the locking groove 40A can be suppressed.

Furthermore, in the disc brake 1 according to the present embodiment, the materials used for the large gear 56 and the sun gear 57 can be optimized. Since the entire sun gear 57, at least the gear portion 57B, can be made of metal, the wear durability of the gear portion 57B of the sun gear 57 can be improved. Further, since the large gear 56 and the sun gear 57 are configured as separate bodies, the minimum backlash in assembling the large gear 56 and the sun gear 57 is an error in assembling the sun gear 57, each planetary gear 60, and the internal gear 61. (Concentric error) can be absorbed, and the degree of meshing with each other can be improved.

Next, another embodiment of the second reduction gear 49 of the planetary gear reduction mechanism 45 will be described with reference to FIGS. 8 to 10. In these other embodiments, the configurations of the relative rotation restricting portions provided between the hole portion 40 of the large gear 56 and the fitting portion 57A of the sun gear 57 are different from each other. In the following description, for convenience of explanation, in FIGS. 8 (b), 9 (b), and 10 (b), the upper side thereof is referred to as one end side and the lower portion thereof is referred to as the other end side.

In the embodiment shown in FIG. 8, a plurality of locking groove portions 40A are formed radially on the inner peripheral surface of the hole portion 40 of the large gear 56. In the present embodiment, the locking groove portions 40A are formed at six locations. The wall surfaces of the adjacent locking grooves 40A and 40A are connected by an arc surface protruding toward the center in the radial direction. In other words, the hole portion 40 including each locking groove portion 40A is formed in a substantially star shape in a plan view. On one end surface of the annular wall portion 39, an annular protrusion 41 projecting from one end side is formed around the hole portion 40 including each locking groove portion 40A. On the other hand, the fitting portion 57A of the sun gear 57 is formed in a shape that can be fitted in contact with each other in the hole portion 40 including each locking groove portion 40A of the large gear 56, that is, a substantially star shape in a plan view. On one end surface of the fitting portion 57A, a concave portion 57D having a substantially star shape in a plan view is formed around the shaft hole 49A.

In the embodiment shown in FIG. 9, the hole 40 of the large gear 56 is formed in a polygonal shape in a plan view. In the present embodiment, the hole 40 is formed in a hexagonal shape in a plan view. On one end surface of the annular wall portion 39, an annular protrusion 41 projecting from one end side is formed around the hole 40. On the other hand, the fitting portion 57A of the sun gear 57 is formed into a polygonal shape in a plan view that can be fitted to the inner wall surface of the hole 40 of the large gear 56 in contact with each other. In the present embodiment, the fitting portion 57A of the sun gear 57 is formed in a hexagonal shape in a plan view. A hexagonal recess 57D in a plan view is formed around the shaft hole 49A on one end surface of the fitting portion 57A.

In the embodiment shown in FIG. 10, the hole 40 of the large gear 56 is formed in a substantially circular shape in a plan view, as in the embodiment shown in FIG. A plurality of locking groove portions 40A are formed on the inner peripheral surface of the hole portion 40 at equal intervals along the circumferential direction (four locations in the present embodiment). The locking groove portion 40A is formed in a U-shape in a plan view. Further, on the other end surface of the annular wall portion 39 of the large gear 56, an annular protrusion 41 projecting to the other end side is formed around the hole portion 40 including each locking groove portion 40A. On the other hand, the fitting portion 57A of the sun gear 57 is formed with a flange portion 57E that projects radially outward from the outer peripheral surface of one end thereof. This fitting portion 57A is engaged with each locking groove portion 40A provided in the hole portion 40 of the large gear 56 on the outer peripheral surface on the other end side from the flange portion 57E, as in the embodiment shown in FIG. The stop pieces 57C are projected outward in the radial direction. The outer peripheral end of the flange portion 57E protrudes radially outward from the tip of each locking piece 57. On one end surface of the fitting portion 57A, a recess 57D having a substantially circular shape in a plan view is formed around the shaft hole 49A. In this embodiment, when the fitting portion 57A of the sun gear 57 is fitted and assembled in the hole 40 of the large gear 56, the flange portion 57E of the sun gear 57 moves the sun gear 57 from the large gear 56 to the other end side of the sun gear 57. Can be prevented. This makes it possible to improve the workability of assembling the large gear 56 and the sun gear 57.

As described above, the above-mentioned planetary gear reduction mechanism 45 is adopted for the disc brake 1 that drives the electric motor 200 to generate braking force when the parking disc brake used for parking braking or the like is operated. However, the above-mentioned planetary gear reduction mechanism 45 may be adopted for the electric disc brake that drives the electric motor 200 to generate a braking force during normal braking.

1 Disc brake, 2 Inner brake pad, 3 Outer brake pad, 6 Caliper body, 18 Piston, 15 Cylinder, 40 holes, 40A locking groove (relative rotation control part), 41 protrusions, 43 rotation linear motion conversion mechanism ( Piston propulsion mechanism), 44 spur tooth multi-stage deceleration mechanism (deceleration mechanism), 45 planetary gear deceleration mechanism (deceleration mechanism), 49 second deceleration gear, 53 large gear (large diameter gear), 57 sun gear (small diameter gear), 57A fitting Combined part, 57B gear part, 57C locking piece (relative rotation control part), 60 planetary gear, 61 internal gear, 200 electric motor (motor), D disc rotor (rotor)

Claims (4)

A pair of pads arranged on both sides of the rotor in the axial direction with the rotor in between,
A piston that presses one of the pair of pads against the rotor,
A caliper body having a cylinder in which the piston is movably housed,
The motor provided in the caliper body and
A deceleration mechanism including a planetary gear deceleration mechanism that increases the rotational force from the motor, and
A piston propulsion mechanism that converts a rotary motion from the deceleration mechanism into a linear motion to propel the piston is provided.
The planetary gear reduction mechanism is
A large diameter gear to which the rotation from the motor is transmitted, and
A small-diameter gear that extends concentrically from the large-diameter gear in the axial direction and has a smaller diameter than the large-diameter gear.
A plurality of planetary gears that mesh with the small diameter gear and are arranged at intervals along the outer peripheral surface of the small diameter gear.
It has an internal gear that meshes with each of the planetary gears.
In the small-diameter gear, at least the gear portion that meshes with the planetary gear is made of metal, and the large -diameter gear and the small-diameter gear are separately formed. A disc brake that is connected via a disc brake , wherein the relative rotation restricting portion includes an arcuate surface that projects toward the radial center of the large diameter gear . The large-diameter gear has a hole formed in the center in the radial direction.
The small diameter gear is formed with a fitting portion to be fitted into the hole portion.
The disc brake according to claim 1, wherein the relative rotation restricting portion is provided between the hole portion of the large diameter gear and the fitting portion of the small diameter gear. The disc brake according to claim 2, wherein a protrusion protruding along the axial direction is formed around the hole of the large-diameter gear. As the relative rotation control unit,
The disc brake according to any one of claims 1 to 3 , wherein the hole portion of the large diameter gear is formed in a shape symmetrical with respect to the center in the radial direction in a plan view shape.

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