Electric parking brake system

Abstract

As an example, we provide an electric parking brake device that can prevent the elastic body from falling off. [Solution] An electric parking brake device according to this embodiment includes, as an example, a motor having a motor case and a shaft extending from the motor case in a first axial direction along the central axis, and configured to rotate the shaft around the central axis, a case having a cylindrical portion with a space for housing the motor provided on the inside, and a lid portion that fits into the cylindrical portion to close one end of the space in a second axial direction opposite to the first axial direction, and an elastic body held by the lid portion and interposed between the motor and the lid portion, wherein the elastic body is held by the lid portion when the lid portion is not fitted into the cylindrical portion.

Description

Technical Field

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[0001] Embodiments of the present invention relate to an electric parking brake device.

Background Art

[0002] Conventionally, an electric parking brake device having a cylindrical portion covering a motor, a lid portion coupled to the cylindrical portion, and a wave washer interposed between the motor and the lid portion is known. The wave washer prevents the vibration of the motor from reaching the lid portion as much as possible by elastic force (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional configuration, the wave washer is not held by the lid. Therefore, when the wave washer is moved or assembled while being installed on the lid or the cylindrical portion, there is a possibility that it may fall off from the cylindrical portion.

[0005] Therefore, the present invention has been made in view of the above, and provides an electric parking brake device capable of suppressing the detachment of an elastic body.

Means for Solving the Problems

[0006] An electric parking brake device according to an embodiment of the present invention comprises, for example, a motor having a motor case and a shaft extending from the motor case in a first axial direction along the central axis, and configured to rotate the shaft around the central axis; a case having a cylindrical portion with a space for housing the motor provided on the inside, and a lid portion that fits into the cylindrical portion to close one end of the space in a second axial direction opposite to the first axial direction; and an elastic body held by the lid portion and interposed between the motor and the lid portion, wherein the elastic body is held by the lid portion when the lid portion is not fitted into the cylindrical portion. Therefore, as an example, in the electric parking brake device, since the elastic body is held by the lid portion when the lid portion is not fitted into the cylindrical portion, it is possible to suppress the elastic body from falling out of the lid portion during movement and assembly, for example. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic cross-sectional view showing an electric parking brake device according to the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing the electric actuator case of the first embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view showing the lid portion of the first embodiment. [Figure 4] Figure 4 is a schematic cross-sectional view showing the lid portion of the second embodiment. [Figure 5] Figure 5 is a schematic cross-sectional view showing the electric actuator case of the third embodiment. [Figure 6] Figure 6 is a schematic diagram showing the cylindrical portion and the lid portion of the third embodiment. [Modes for carrying out the invention]

[0008] Embodiments will be described below with reference to the drawings. Note that in this specification, components and descriptions of such components may be expressed in multiple ways. The components and their descriptions are examples and are not limited by the expressions used herein. Components may also be identified by names different from those used herein. Furthermore, components may also be described by expressions different from those used herein.

[0009] In the following explanation, “suppress” is defined, for example, to prevent the occurrence of an event, action, or effect, or to reduce the degree of an event, action, or effect. Also, in the following explanation, “restrict” is defined, for example, to prevent movement or rotation, or to permit movement or rotation within a predetermined range while preventing movement or rotation beyond that predetermined range.

[0010] Furthermore, the direction is indicated in each diagram. The X, Y, and Z directions intersect (are orthogonal) to each other. An example of the first axis direction, which runs from the motor case along the central axis, is the +X direction. An example of the second axis direction, which is opposite to the first axis direction, is the -X direction.

[0011] Figure 1 is a schematic cross-sectional view showing an electric parking brake device 2 according to a first embodiment. As shown in Figure 1, the electric parking brake device 2 is a disc brake mounted on a vehicle 1, such as a four-wheeled automobile. The electric parking brake device 2 may also be referred to as a braking device.

[0012] The electric parking brake system 2 includes a disc rotor 3 and an electric parking brake (EPB) 4.

[0013] The disc rotor 3 rotates integrally with the wheel of the vehicle 1 around the central axis Axd. The central axis Axd is, for example, the central axis of the axle, the central axis of the disc rotor 3, and the central axis of rotation of the disc rotor 3. Note that the central axis Axd is not limited to this example. In this embodiment, the central axis Axd extends in the X direction.

[0014] The electric parking brake 4 can operate as a hydraulic service brake and also as an electric brake. The electric parking brake 4 of this embodiment includes a brake caliper 41, a pair of brake pads 42, and a drive unit 43. The drive unit 43 may also be referred to as a motor gear unit (MGU).

[0015] For example, the brake caliper 41 and brake pad 42 constitute a hydraulic service brake, and the brake caliper 41, brake pad 42, and drive unit 43 constitute an electric brake. The electric parking brake 4 is configured so that the braking state due to the electric braking function is maintained when parked. The electric brake may also operate when driving or when stopped.

[0016] The brake caliper 41 is, for example, a floating caliper. The brake caliper 41 has a caliper body 44, a rotary-to-linear motion conversion mechanism 45, and a piston 49. The caliper body 44 may also be referred to as a cylinder, for example.

[0017] The caliper body 44 is positioned to straddle the disc rotor 3 and is supported on the vehicle body of the vehicle 1 so as to be movable in the X direction, for example via a mount. The caliper body 44 houses a rotary-to-linear motion conversion mechanism 45. Furthermore, the caliper body 44 supports a piston 49 so as to be movable along a central axis Axc. The central axis Axc is, for example, the central axis of the hole in which the piston 49 is housed and extends in the X direction.

[0018] The rotary-linear motion conversion mechanism 45 has a rotating member 46 and a linear motion member 47. The rotating member 46 can also be referred to as a bolt. The linear motion member 47 can also be referred to as a nut.

[0019] The rotating member 46 is formed, for example, in a substantially cylindrical shape extending along the central axis Axc. Also, the rotating member 46 may have a flange substantially orthogonal to the central axis Axc. The rotating member 46 is supported by the caliper body 44 so as to be rotatable about the central axis Axc, for example, via a bearing.

[0020] The linear motion member 47 is formed, for example, in a substantially cylindrical shape extending along the central axis Axc. The linear motion member 47 is attached to the piston 49, for example, with rotation about the central axis Axc restricted. The rotating member 46 extends in the X direction through the inside of the cylindrical linear motion member 47.

[0021] For example, the rotating member 46 and the linear motion member 47 are attached to each other by engagement of a male screw provided on the rotating member 46 and a female screw provided on the linear motion member 47, or by engagement via balls. That is, the linear motion member 47 is attached to the rotating member 46 so as to move in the X direction along the central axis Axc in accordance with the rotation of the rotating member 46.

[0022] The pair of brake pads 42 are spaced apart from each other in the X direction along the central axis Axc. One of the pair of brake pads 42 contacts the piston 49. A disk rotor 3 is disposed between the pair of brake pads 42.

[0023] The drive device 43 is attached to the caliper body 44. The drive device 43 rotates the rotating member 46 about the central axis Axc by being driven by drive power based on a control signal.

[0024] When the drive device 43 rotates the rotating member 46 in one direction about the central axis Axc, the linear motion member 47 moves straight (moves) in the -X direction. The piston 49 is pushed in the -X direction by the linear motion member 47 moving in the -X direction, and presses one of the brake pads 42 against the disk rotor 3.

[0025] When one brake pad 42 is pressed against the disc rotor 3, the caliper body 44 moves in the +X direction due to the recoil. As a result, the other brake pad 42 is pushed in the +X direction by the caliper body 44. Thus, the pair of brake pads 42 are pressed against the disc rotor 3. As a result, the electric parking brake device 2 obtains a braking state by electric braking, in which the wheel of the vehicle 1, which rotates integrally with the disc rotor 3, is braked.

[0026] When the drive unit 43 rotates the rotating member 46 in the opposite direction around the central axis Axc, the linear motion member 47 moves in a straight line in the +X direction. Along with the linear motion member 47 moving in the +X direction, the piston 49 also moves in the +X direction.

[0027] As the piston 49 moves in the +X direction, the pressing force from the piston 49 decreases, releasing the pressure of one brake pad 42 against the disc rotor 3. This causes the caliper body 44 to move in the -X direction, releasing the pressure of the other brake pad 42 against the disc rotor 3 as well. In other words, the electric parking brake device 2 achieves a state of release from braking by the electric brake (non-braking state).

[0028] The drive unit 43 includes, for example, a motor 5, a rotation transmission mechanism 6, an electric actuator case 7, a cover 8, and an elastic body 9. The electric actuator case 7 is an example of a case. For example, the drive unit 43 is formed by housing the motor 5 and the rotation transmission mechanism 6 in the electric actuator case 7 and then attaching the cover 8 to the electric actuator case 7.

[0029] Motor 5 is, for example, a three-phase brushless motor. Motor 5 may be of other types. Motor 5 comprises a motor body 50 and a motor shaft 51. The motor shaft 51 is an example of a shaft.

[0030] The motor body 50 has a motor case 52. Furthermore, the motor body 50 has a rotor and a stator. The motor case 52 houses the rotor and stator. The motor case 52 has an end face 521 and a bottom face 522. The end face 521 is formed at the end of the motor case 52 in the +X direction. The bottom face 522 is located on the opposite side of the end face 521. That is, the bottom face 522 is formed at the end of the motor case 52 in the -X direction.

[0031] The motor shaft 51 is coupled to the rotor of the motor body 50. The motor shaft 51 and the rotor of the motor body 50 may be integrally formed.

[0032] The motor shaft 51 is formed in a substantially cylindrical shape extending along the central axis Axm. The central axis Axm is, for example, the central axis of the motor shaft 51 and the rotor and stator of the motor body 50, and extends in the X direction. Note that the central axis Axm is not limited to this example. The central axis Axm of the motor shaft 51 is spaced apart in the -Y direction from the central axis Axc of the caliper body 44.

[0033] The motor shaft 51 extends from the end face 521 of the motor case 52 in the +X direction. The motor 5 rotates the motor shaft 51 around the central axis Axm.

[0034] The rotational transmission mechanism 6 includes two small gears 61 and 62, two large gears 63 and 64, a planetary gear mechanism 65, and two shafts 66 and 67.

[0035] The small gear 61 is mounted on the motor shaft 51 of the motor 5. Therefore, the small gear 61 can rotate integrally with the motor shaft 51 around the central axis Axm.

[0036] The large gear 63 and the small gear 62 are mounted on the shaft 66. The shaft 66 extends along the central axis Axi. The central axis Axi is the central axis of the shaft 66 and extends in the X direction. Note that the central axis Axi is not limited to this example.

[0037] The large gear 63 and the small gear 62 are spaced apart from each other in the X direction. The large gear 63 meshes with the small gear 61. Therefore, the small gear 61 and the large gear 63 can transmit rotation to each other. The small gear 62 is rotatable integrally with the large gear 63 and the shaft 66 around the central axis Axi.

[0038] The large gear 64 is mounted on the shaft 67. The shaft 67 extends along the central axis Axc. The large gear 64 has a larger outer diameter and pitch circle diameter than the small gear 62. Furthermore, the large gear 64 has more teeth than the small gear 62. The large gear 64 meshes with the small gear 62. Therefore, the small gear 62 and the large gear 64 can transmit rotation to each other.

[0039] The large gear 64 also serves as a planetary carrier for the planetary gear mechanism 65, for example. Therefore, the large gear 64 supports multiple planetary gears of the planetary gear mechanism 65. As a result, the planetary carrier and planetary gears of the planetary gear mechanism 65 are rotatable integrally with the shaft 67 around the central axis Axc.

[0040] The sun gear of the planetary gear mechanism 65 is connected to the rotating member 46 of the rotary-to-linear motion conversion mechanism 45. Therefore, the planetary gear mechanism 65 reduces the rotation of the large gear 64 and transmits it to the rotating member 46. Note that the planetary gear mechanism 65 is not limited to the above example. Also, the large gear 64 may be connected to the rotating member 46 without going through the planetary gear mechanism 65.

[0041] As described above, the rotation transmission mechanism 6 transmits rotation between the motor shaft 51 of the motor 5 and the rotating member 46. In other words, the motor 5 can drive the rotating member 46 through the rotation transmission mechanism 6.

[0042] The electric actuator case 7 is made of, for example, resin. The electric actuator case 7 houses the motor 5, two small gears 61 and 62, two large gears 63 and 64, and a planetary gear mechanism 65.

[0043] The cover 8 is mounted on the electric actuator case 7 so as to cover the motor shaft 51 of the motor 5, the two small gears 61 and 62, the two large gears 63 and 64, and the planetary gear mechanism 65. The electric actuator case 7 and the cover 8 support the shafts 66 and 67.

[0044] Next, the mounting structure of the electric actuator case 7 will be described using Figure 2. Figure 2 is a schematic cross-sectional view showing the electric actuator case 7 of the first embodiment.

[0045] As shown in Figure 2, the electric actuator case 7 has a cylindrical portion 71, a support portion 72, and a lid portion 73.

[0046] The cylindrical portion 71 is formed in a substantially cylindrical shape extending along the central axis Axm. Therefore, a space 75 is provided inside the cylindrical portion 71. The motor body 50 of the motor 5 is housed in the space 75. An opening 751 into which the motor 5 can be inserted is provided at the end of the cylindrical portion 71 in the -X direction. The opening 751 is the end of the space 75.

[0047] The cylindrical portion 71 has an inner circumferential surface 711. The inner circumferential surface 711 is a substantially cylindrical curved surface extending along the central axis Axm and facing the central axis Axm. A groove 712 is provided in the cylindrical portion 71. The cylindrical portion 71 further has a locking surface 713 provided at the end of the groove 712 in the -X direction. The locking surface 713 faces the +X direction. The locking surface 713 may also be provided on a projection protruding from the inner circumferential surface 711.

[0048] The support portion 72 is formed at the +X end of the space 75. The support portion 72 supports the end face 521 of the motor case 52. The support portion 72 is provided with a through hole 721 through which the motor shaft 51 passes.

[0049] Figure 3 is a schematic cross-sectional view of the lid 73 of the first embodiment. As shown in Figure 3, the lid 73 has a bottom wall 731, a cylindrical wall 732, and a plurality of fitting claws 733. The bottom wall 731 closes the -X end of the space 75. The cylindrical wall 732 is formed in a cylindrical shape extending along the central axis Axm and protrudes from the bottom wall 731 in the +X direction.

[0050] The cylindrical wall 732 fits inside the cylindrical portion 71 so as to surround it. For example, the cylindrical wall 732 is inserted into the space 75 through the opening 751. The lid portion 73 closes the -X end of the space 75 with its bottom wall 731 when the cylindrical wall 732 fits into the cylindrical portion 71. Alternatively, the cylindrical wall 732 may fit into the cylindrical portion 71 by surrounding it.

[0051] Multiple interlocking claws 733 are spaced apart from each other around the central axis Axm and protrude from the cylindrical wall 732 in the +X direction. The interlocking claws 733 can overcome the inner circumferential surface 711 by elastic deformation and fit into the groove 712. The interlocking claws 733 engage with the locking surface 713. That is, the lid 73 is attached to the cylindrical portion 71 by a snap fit between the interlocking claws 733 and the groove 712. In this way, the lid 73 is attached to the cylindrical portion 71 by an elastic force expanding in the Y direction (radial direction of the central axis Axm). Note that the lid 73 may have a groove and the cylindrical portion 71 may have interlocking claws. Alternatively, the lid 73 may be attached to the cylindrical portion 71 by other methods utilizing the radial elastic force of the central axis Axm.

[0052] The lid portion 73 is attached to the cylindrical portion 71 by snap-fitting and then fixed to the cylindrical portion 71 by welding. Examples of welding include vibration welding and laser welding. The lid portion 73 may also be fixed to the cylindrical portion 71 by heat riveting. If the lid portion 73 and the cylindrical portion 71 are made of metal, they may be fixed to each other by welding.

[0053] The elastic body 9 is formed in an annular shape extending around a central axis Axm, and examples include rubber, washers (wave washers, spring washers), and leaf springs. The elastic body 9 has an inner circumferential surface 90 and an outer circumferential surface 91.

[0054] The inner circumferential surface 90 and the outer circumferential surface 91 extend in an annular shape around the central axis Axm. The inner circumferential surface 90 faces the central axis Axm. The outer circumferential surface 91 is located on the opposite side of the inner circumferential surface 90. The outer circumferential surface 91 is held in place by the lid portion 73 by fitting inside the cylindrical wall 732 with an overlap.

[0055] The elastic body 9 fits inside the cylindrical wall 732 by bringing its outer surface 91 into contact with the cylindrical wall 732 while undergoing elastic deformation. That is, the natural diameter of the outer surface 91 is greater than or equal to the inner diameter of the cylindrical wall 732. The elastic body 9 is held in place by the lid portion 73 by friction between the outer surface 91 and the cylindrical wall 732. That is, the elastic body 9 is held in place by the lid portion 73 even when the lid portion 73 is not fitted into the cylindrical portion 71. The elastic body 9 may also be held in place by the lid portion 73 without undergoing elastic deformation.

[0056] The elastic body 9 is interposed between the motor 5 and the lid 73. Specifically, the elastic body 9 is interposed between the bottom surface 522 of the motor case 52 and the bottom wall 731 of the lid 73. The elastic body 9 is compressed between the motor 5 and the lid 73.

[0057] The electric actuator case 7 houses the motor 5 through the opening 751 of the cylindrical portion 71 and secures it with the cylindrical portion 71 and the lid portion 73. Conventionally, electric actuator cases are formed with the cylindrical portion and the lid portion as a single unit. Therefore, when housing a motor in the electric actuator case, a bracket is required to secure the motor. In addition, a fixing member is required to secure the bracket to the electric actuator case. In this embodiment, since brackets and fixing members are not required, the number of parts can be reduced.

[0058] In the first embodiment described above, as an example, the electric parking brake device 2 can be easily attached to the cylindrical portion 71 by bending the fitting claws 733 of the cover portion 73 into the grooves 712 of the cylindrical portion 71. Therefore, it is possible to prevent the cover portion 73 from coming off the cylindrical portion 71.

[0059] The elastic body 9 is held by the lid portion 73 when the lid portion 73 is not fitted into the cylindrical portion 71. Therefore, the electric parking brake device 2 can prevent the elastic body 9 from falling off the lid portion 73, for example, during movement and assembly.

[0060] The end face 521 of the motor case 52 is supported by the support portion 72. The bottom face 522 of the motor case 52 is supported by the lid portion 73 via the elastic body 9. This restricts the movement of the motor 5 in the X direction. Furthermore, the elastic body 9 can suppress vibrations of the motor 5.

[0061] The elastic body 9 fits into the lid portion 73 by its outer peripheral surface 91 contacting the cylindrical wall 732 of the lid portion 73. Therefore, the electric parking brake device 2 can prevent the elastic body 9 from falling out of the lid portion 73. Furthermore, when the elastic body 9 is in contact with and fitted into the cylindrical wall 732 of the lid portion 73, it applies an elastic force to the cylindrical wall 732 of the lid portion 73. Therefore, the electric parking brake device 2 can prevent the fitting claw 733 of the lid portion 73 from coming out of the groove 712 of the cylindrical portion 71 due to the elastic force of the elastic body 9.

[0062] Next, the mounting structure of the lid portion 73 and the elastic body 9 in the second embodiment will be described using Figure 4. Figure 4 is a schematic cross-sectional view showing the lid portion 73 in the second embodiment. Note that the same configuration as in the first embodiment will not be described.

[0063] As shown in Figure 4, the lid portion 73 further has a projection portion 735. The projection portion 735 is formed in a cylindrical shape extending along the central axis Axm. The projection portion 735 may be formed in other shapes, such as a cylindrical shape. The projection portion 735 protrudes from the bottom wall 731 in the +X direction and is surrounded by the cylindrical wall 732.

[0064] The elastic body 9 is held in place by fitting onto the protrusion 735 with an overlap. The elastic body 9 is held in place by its inner circumferential surface 90 contacting the protrusion 735. The elastic body 9 is positioned such that a gap is provided between the cylindrical wall 732 and the outer circumferential surface 91 of the elastic body 9.

[0065] In the second embodiment described above, as an example, the inner circumferential surface 90 of the elastic body 9 is fitted into the protruding portion 735 of the lid portion 73. As a result, the electric parking brake device 2 can have a gap between the cylindrical wall 732 of the lid portion 73 and the outer circumferential surface 91 of the elastic body 9, making it easier for the fitting claw 733 to bend. Therefore, the lid portion 73 is easier to fit into the cylindrical portion 71.

[0066] Next, the mounting structure of the electric actuator case 7 in the third embodiment will be described using Figure 5. Figure 5 is a schematic cross-sectional view of the electric actuator case 7 in the third embodiment. Note that the same configuration as in the first embodiment will not be described.

[0067] As shown in Figure 5, the cylindrical portion 71 is provided with a first groove 715 and a second groove 716 instead of the groove 712. The first groove 715 extends in the +X direction from the end of the cylindrical portion 71 in the -X direction. Note that the first groove 715 is not limited to this example and may extend diagonally, for example. The second groove 716 extends around the central axis Axm from the +X end of the first groove 715. The cylindrical portion 71 also has a locking surface 717 provided in the second groove 716. In the third embodiment, the locking surface 717 is located at the end of the second groove 716 around the central axis Axm and is formed by the end of the second groove 716 being recessed in the -X direction to be shorter than the first groove 715.

[0068] Figure 6 is a schematic diagram showing the cylindrical portion 71 and the lid portion 73 of the third embodiment. As shown in Figure 6, the fitting claw 733 fits into the second groove 716 and engages with the locking surface 717. This attaches the lid portion 73 to the cylindrical portion 71, and the fitting claw 733 restricts the lid portion 73 from moving in the -X direction relative to the cylindrical portion 71.

[0069] When the lid portion 73 is fitted inside the cylindrical portion 71, the engaging claw 733 moves in the +X direction within the first groove 715. As the lid portion 73 is rotated around the central axis Axm, the engaging claw 733 moves from the first groove 715 to the central axis Axm along the second groove 716. For example, when the elastic body 9 pushes the lid portion 73 in the -X direction by elastic force, the engaging claw 733 engages with the locking surface 717.

[0070] In the third embodiment described above, as an example, the cylindrical portion 71 is provided with a first groove 715 extending from the end of the cylindrical portion 71 and a second groove 716 extending from the first groove 715 around the central axis Axm. The fitting claw 733 engages with the second groove 716, thereby restricting the lid portion 73 from moving in the -X direction relative to the cylindrical portion 71. That is, the lid portion 73 can be attached to the cylindrical portion 71 by being rotated around the central axis Axm.

[0071] In the above embodiments, the electric parking brake device 2 is described using a disc brake as an example, but it may also be a drum brake. For example, the rotary-to-linear motion conversion mechanism 45 may be connected to the brake shoe via a mechanism such as a cable. In this case, the drum brake may be braked by the rotary-to-linear motion conversion mechanism 45 pulling the cable.

[0072] An electric parking brake device according to at least one embodiment described above includes, as an example, a motor having a motor case and a shaft extending from the motor case in a first axial direction along the central axis, and configured to rotate the shaft around the central axis, a case having a cylindrical portion with a space for housing the motor provided on the inside, and a lid portion that fits into the cylindrical portion to close one end of the space in a second axial direction opposite to the first axial direction, and an elastic body held by the lid portion and interposed between the motor and the lid portion, wherein the elastic body is held by the lid portion when the lid portion is not fitted into the cylindrical portion. Therefore, as an example, the electric parking brake device can suppress the elastic body from falling out of the lid portion, for example, during movement and assembly, because the elastic body is held by the lid portion even when the lid portion is not fitted into the cylindrical portion.

[0073] In the above-described electric parking brake device, for example, the lid portion has a cylindrical wall that fits into the cylindrical portion, and the elastic body is held in place by fitting inside the cylindrical wall with an overlap. Therefore, in one example, because the elastic body fits inside the cylindrical wall of the lid portion, the electric parking brake device can prevent the elastic body from falling out of the lid portion.

[0074] In the above-described electric parking brake device, for example, the cover portion has a bottom wall that seals the space, a cylindrical wall that protrudes from the bottom wall and fits into the cylindrical portion, and a protruding portion that protrudes from the bottom wall and is surrounded by the cylindrical wall, and the elastic body is held in place by fitting into the protruding portion with an overlap. Therefore, for example, in the electric parking brake device, the elastic body is held in place by surrounding the protruding portion of the cover portion, thus preventing the elastic body from falling out of the cover portion.

[0075] In the above-described electric parking brake device, for example, the cover is attached to the cylindrical part by radial elastic force. Therefore, for example, the cover can be easily attached to the cylindrical part of the electric parking brake device.

[0076] In the above-described electric parking brake device, for example, the cylindrical portion is provided with a first groove extending from the end of the cylindrical portion in the second axial direction and a second groove extending from the first groove around the central axis, and the lid portion has a fitting claw that fits into the second groove, thereby restricting the lid portion from moving in the second axial direction relative to the cylindrical portion. Therefore, for example, in the electric parking brake device, the fitting claw can be fitted from the first groove to the second groove of the cylindrical portion by rotating the lid portion around the central axis, and the lid portion can be easily attached to the cylindrical portion.

[0077] Although embodiments of the present invention have been illustrated above, these embodiments and modifications are merely examples and are not intended to limit the scope of the invention. The above embodiments and modifications can be implemented in various other forms, and various omissions, substitutions, combinations, and changes can be made without departing from the spirit of the invention. Furthermore, the configurations and shapes of each embodiment and modification can be partially replaced. [Explanation of Symbols]

[0078] 2...Electric parking brake device, 5...Motor, 7...Electric actuator case (case), 9...Elastic body, 51...Motor shaft (shaft), 52...Motor case, 71...Cylindrical section, 73...Lid section, 75...Space, 733...Matching claw, 715...First groove, 716...Second groove, 731...Bottom wall, 732...Cylindrical wall, 735...Protruding section.

Claims

1. A motor comprising a motor case and a shaft extending from the motor case in a first axial direction along the central axis, configured to rotate the shaft around the central axis, A case having a cylindrical portion with an internal space for housing the motor, and a lid portion that fits into the cylindrical portion and closes one end of the space in the second axial direction opposite to the first axial direction, The system comprises an elastic body held in the lid and interposed between the motor and the lid, The elastic body is held by the lid when the lid is not fitted into the cylindrical portion. Electric parking brake system.

2. The lid portion has a cylindrical wall that fits into the cylindrical portion. The elastic body is held in place by fitting inside the cylindrical wall with an overlap. The electric parking brake device according to claim 1.

3. The lid portion has a bottom wall that closes the space, a cylindrical wall that protrudes from the bottom wall and fits into the cylindrical portion, and a protruding portion that protrudes from the bottom wall and is surrounded by the cylindrical wall. The elastic body is held in place by fitting into the protrusion with an overlap, The electric parking brake device according to claim 1.

4. The lid portion is attached to the cylindrical portion by radial elastic force. An electric parking brake device according to any one of claims 1 to 3.

5. The cylindrical portion is provided with a first groove extending from the end of the cylindrical portion in the second axial direction, and a second groove extending from the first groove around the central axis. The lid portion has a fitting claw that fits into the second groove, thereby restricting the lid portion from moving in the second axial direction relative to the cylindrical portion. An electric parking brake device according to any one of claims 1 to 3.

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