Braking device

Abstract

To provide a braking device as one example that can be reduced in weight.SOLUTION: A braking device according to an embodiment as one example is provided with: a backing plate; a braking member configured to brake a wheel by contacting a drum rotor and supported on the backing plate; a rotating member that can rotate around a central axis; a direct-acting member mounted on the rotating member so as to move in an axial direction in accordance with rotation of the rotating member; a cable supported on the direct-acting member and configured to make the braking member contact the drum rotor by being pulled by the direct-acting member; a support surface mounted on the backing plate to support the rotating member; and a first case which has a first part made of metal provided between the support surface and the backing plate and surrounds the cable, and a second part made of resin formed integrally with the first part, which stores at least a portion of the rotating member.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a braking device. [Background technology]

[0002] Conventionally, braking devices have been known that include a unit that moves a brake shoe by pulling a cable. The unit includes, for example, a motor, a mechanism that converts the rotation of the motor into linear motion to pull the cable, and a case that houses the motor and the mechanism (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-83010 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional configuration, the entire unit case is made of metal, which makes the braking device heavy. On the other hand, since the case receives reaction force from the pulled cable, it is difficult to make the entire case out of resin.

[0005] Therefore, the present invention has been made in view of the above, and provides a braking device that can be made lighter. [Means for solving the problem]

[0006] The braking device according to an embodiment of the present invention is configured, as an example, to brake the wheel by contacting a drum rotor that rotates integrally with the wheel, and includes a braking member supported by the backing plate, a rotating member rotatable about a central axis, a linear motion member attached to the rotating member so as to move in an axial direction along the central axis in response to the rotation of the rotating member, a cable supported by the linear motion member and configured to bring the braking member into contact with the drum rotor by being pulled by the linear motion member, a support surface attached to the backing plate and supporting the rotating member, a first metal portion provided between the support surface and the backing plate and surrounding the cable, and a second resin portion formed integrally with the first portion and at least partially accommodating the rotating member. Thus, as an example, when the linear motion member pulls the cable, the reaction force of the cable acts on the support surface via the linear motion member and the rotating member. The first case can obtain strength capable of withstanding the reaction force by providing the first metal portion between the support surface and the backing plate. On the other hand, the first case has a second resin portion as a portion for accommodating the rotating member on which the reaction force hardly acts. Generally, the density of resin is smaller than that of metal. Thereby, the braking device can be made lighter than when the entire first case is made of metal.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0008] One embodiment will be described below with reference to FIGS. 1 to 3. In this specification, the components according to the embodiment and the descriptions of the components may be described in a plurality of expressions. The components and their descriptions are examples and are not limited by the expressions in this specification. The components may be specified by different names from those in this specification. Also, the components may be described by expressions different from those in this specification.

[0009] In the following description, "suppress" is defined as, for example, preventing the occurrence of an event, action, or influence, or reducing the degree of an event, action, or influence. Also, in the following description, "restrict" is defined as, for example, preventing movement or rotation, or allowing movement or rotation within a predetermined range and preventing movement or rotation beyond the predetermined range.

[0010] FIG. 1 is a side view showing the braking device 10 according to this embodiment. FIG. 2 is a rear view showing the braking device 10 of this embodiment. As shown in FIG. 2, the braking device 10 is a drum brake mounted on a vehicle 1 such as an automobile.

[0011] The braking device 10 is disposed inside the cylindrical peripheral wall 2a of the wheel 2. The braking device 10 may be disposed inside any of the driving wheels and non-driving wheels of the wheel 2. Note that the braking device 10 is not limited to this example.

[0012] As shown in FIGS. 1 and 2, in this specification, for convenience, the X-axis, Y-axis, and Z-axis are defined. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The X-axis is provided along the width of the braking device 10. The Y-axis is provided along the thickness of the braking device 10. The Z-axis is provided along the height of the braking device 10. The X-axis extends substantially in the front-rear direction of the vehicle 1. Also, the Y-axis extends substantially in the width direction (vehicle width direction) of the vehicle 1.

[0013] Furthermore, in this specification, the X-direction, Y-direction, and Z-direction are defined. The X-direction (longitudinal direction) is the direction along the X-axis, including the +X direction indicated by the arrow of the X-axis and the -X direction opposite to the direction of the arrow of the X-axis. The Y-direction (vehicle width direction) is the direction along the Y-axis, including the +Y direction (outside the vehicle width direction) indicated by the arrow of the Y-axis and the -Y direction (inside the vehicle width direction) opposite to the direction of the arrow of the Y-axis. The Z-direction (height direction) is the direction along the Z-axis, including the +Z direction (upward direction) indicated by the arrow of the Z-axis and the -Z direction (downward direction) opposite to the direction of the arrow of the Z-axis.

[0014] As shown in FIG. 1, the braking device 10 includes two brake shoes 11, a backing plate 12, an anchor 13, a wheel cylinder 14, a motor gear unit (MGU) 15, a spring 16, and a moving mechanism 17. The brake shoe 11 is an example of a braking member.

[0015] The two brake shoes 11 are spaced apart from each other in the X-direction. The two brake shoes 11 extend substantially in an arc shape along the cylindrical inner peripheral surface 3a of the drum rotor 3 shown in FIG. 2. The drum rotor 3 may also be referred to as a brake drum.

[0016] The drum rotor 3 is attached to the wheel 2. The drum rotor 3 rotates integrally with the wheel 2 about a central axis Axd extending in the Y-direction. The central axis Axd is the central axis of the wheel 2 and the drum rotor 3.

[0017] The backing plate 12 is formed in a substantially disk shape arranged so as to be substantially orthogonal to the central axis Axd. The backing plate 12 is connected to the vehicle body of the vehicle 1, for example, via a part of the suspension. The backing plate 12 supports various elements of the braking device 10.

[0018] The anchor 13 is attached to the backing plate 12 near the end of the backing plate 12 in the -Z direction. The wheel cylinder 14 is attached to the backing plate 12 near the end of the backing plate 12 in the +Z direction. The two brake shoes 11, the anchor 13, the wheel cylinder 14, the spring 16, and the moving mechanism 17 are located outside the backing plate 12 in the vehicle width direction. On the other hand, the MGU 15 is attached to the backing plate 12 so as to protrude inward in the vehicle width direction from the backing plate 12.

[0019] The end 11a of the brake shoe 11 in the -Z direction is supported by the anchor 13 so as to be rotatable around the end 11a. Thereby, the brake shoe 11 is supported by the backing plate 12 via the anchor 13. Further, the end 11b of the brake shoe 11 in the +Z direction is supported by the movable part of the wheel cylinder 14.

[0020] Each of the two brake shoes 11 has a strip-shaped lining 11c. The braking device 10 moves the two brake shoes 11 so as to press the lining 11c against the inner peripheral surface 3a of the drum rotor 3. Thereby, the drum rotor 3 and the wheel 2 are braked by the friction between the lining 11c and the inner peripheral surface 3a of the drum rotor 3. That is, the brake shoe 11 brakes the wheel 2 by contacting the drum rotor 3 that rotates integrally with the wheel 2.

[0021] The braking device 10 moves the brake shoe 11 by the hydraulic pressure of the wheel cylinder 14, for example, while the vehicle 1 is running. On the other hand, when the vehicle 1 is parked, the braking device 10 moves the brake shoe 11 by the MGU 15. That is, the braking device 10 is a so-called electric parking brake. Note that the MGU 15 may move the brake shoe 11 while the vehicle 1 is running.

[0022] The wheel cylinder 14 presses the end 11b of the brake shoe 11 according to the hydraulic pressure. As a result, the two brake shoes 11 rotate around the end 11a, and the ends 11b of the two brake shoes 11 move away from each other in the X direction. Thereby, the two brake shoes 11 move toward the inner peripheral surface 3a of the drum rotor 3, and the lining 11c is pressed against the inner peripheral surface 3a of the drum rotor 3.

[0023] The spring 16 pulls the two brake shoes 11 closer to each other. When the operation of pressing the brake shoe 11 by the wheel cylinder 14 is released, the spring 16 separates the two brake shoes 11 from the inner peripheral surface 3a of the drum rotor 3.

[0024] The MGU 15 moves the two brake shoes 11 via the moving mechanism 17. The moving mechanism 17 includes a lever 21, a pin 22, a cable 23, a strut 24, and a pipe member 25.

[0025] The lever 21, one of the brake shoes 11 (11L), and the backing plate 12 are arranged in a direction along the central axis Axd. The pin 22 attaches the end 21a of the lever 21 in the +Z direction to the brake shoe 11L in the vicinity of the end 11b. The lever 21 and the brake shoe 11L are rotatably attached to each other around the pin 22.

[0026] The cable 23 passes through the backing plate 12 and extends between the MGU 15 and the lever 21. One end 23a of the cable 23 is attached to the end 21b of the lever 21 in the -Z direction. The MGU 15 can pull the lever 21 via the cable 23 so that the end 21b of the lever 21 approaches the central axis Axd.

[0027] The strut 24 is interposed between the lever 21 attached to one of the brake shoes 11L and the other brake shoe 11 (11R). The strut 24 abuts against the lever 21 between the two ends 21a and 21b of the lever 21.

[0028] The pipe member 25 surrounds a part of the cable 23. Thereby, the pipe member 25 protects the cable 23 and guides the cable 23. The pipe member 25 is made of, for example, metal and maintains a shape for guiding the cable 23.

[0029] When the MGU 15 pulls the lever 21 via the cable 23, the lever 21 pushes the brake shoe 11R via the strut 24. Thereby, the brake shoe 11R rotates around the end 11a and presses the lining 11c against the inner peripheral surface 3a of the drum rotor 3.

[0030] Furthermore, as the lever 21 rotates with the strut 24 as a fulcrum, the lever 21 pushes the brake shoe 11L via the pin 22. Thereby, the brake shoe 11L rotates around the end 11a and presses the lining 11c against the inner peripheral surface 3a of the drum rotor 3. The brake shoes 11R and 11L brake the drum rotor 3 and the wheel 2 by pressing the lining 11c against the inner peripheral surface 3a of the drum rotor 3.

[0031] FIG. 3 is a cross-sectional view showing the MGU 15 of the present embodiment. As shown in FIG. 3, the MGU 15 includes a housing 31, a motor 32, a speed reduction mechanism 33, a motion conversion mechanism 34, a bearing 35, a cable end 36, a guide member 37, and a pipe seal 38. The pipe seal 38 is an example of a seal member.

[0032] The housing 31 houses the other end 23b of the cable 23, the motor 32, the speed reduction mechanism 33, the motion conversion mechanism 34, the bearing 35, the cable end 36, the guide member 37, and the pipe seal 38. The housing 31 is attached to the backing plate 12 by, for example, bolts.

[0033] The motor 32 has an output shaft 41. The motor 32 is controlled by a control device such as an ECU and rotates the output shaft 41. The motor 32 may also be referred to as an actuator.

[0034] The speed reduction mechanism 33 has a plurality of gears 45, 46, 47 rotatably supported by the housing 31 and a support shaft 48. The gear 45 is attached to the output shaft 41 of the motor 32. The gear 46 is supported by the support shaft 48. The gear 45 and the gear 46 mesh with each other, and the gear 46 and the gear 47 mesh with each other. The speed reduction mechanism 33 reduces the rotation of the output shaft 41 and transmits it to the motion conversion mechanism 34.

[0035] The motion conversion mechanism 34 has a rotating member 51 and a linear motion member 52. The rotating member 51 and the linear motion member 52 are each formed in a substantially cylindrical shape extending along the central axis Axc. The central axis Axc is, for example, the central axis of the rotating member 51 and the linear motion member 52. Note that the rotating member 51 and the linear motion member 52 are not limited to this example.

[0036] In this specification, for convenience, the axial direction, the radial direction, and the circumferential direction are defined. The axial direction is the direction along the central axis Axc. The axial direction includes a first axial direction Dx1 which is one direction along the central axis Axc and a second axial direction Dx2 which is opposite to the first axial direction Dx1. The radial direction is the direction orthogonal to the central axis Axc. The circumferential direction is the direction around the central axis Axc.

[0037] The rotating member 51 has a cylindrical wall 55 and a flange 56. The cylindrical wall 55 is formed in a substantially cylindrical shape extending along the central axis Axc. The flange 56 is formed in a substantially disk shape protruding radially outward from the cylindrical wall 55. The gear 47 of the speed reduction mechanism 33 is provided at the end of the flange 56 on the radially outer side.

[0038] The gear 47 provided on the flange 56 can transmit rotation between the output shaft 41 and the gear 47 via a plurality of other gears 45, 46 included in the speed reduction mechanism 33. Therefore, the rotation of the output shaft 41 is transmitted to the rotating member 51 via the speed reduction mechanism 33. The rotating member 51 rotates around the central axis Axc in conjunction with the output shaft 41.

[0039] The cylinder wall 55 has a first outer peripheral surface 55a, a second outer peripheral surface 55b, and a male thread 55c. The first outer peripheral surface 55a and the second outer peripheral surface 55b are substantially cylindrical curved surfaces extending along the central axis Axc and facing outward in the radial direction. The first outer peripheral surface 55a extends from the flange 56 in the first axial direction Dx1. The second outer peripheral surface 55b extends from the flange 56 in the second axial direction Dx2. That is, the second outer peripheral surface 55b is spaced apart from the first outer peripheral surface 55a in the second axial direction Dx2. The male thread 55c is provided on the second outer peripheral surface 55b.

[0040] The cable 23 extends axially through the inside of the substantially cylindrical cylinder wall 55. Inside the housing 31, the cable 23 extends, for example, along the central axis Axc. That is, the central axis Axc is also the central axis of the cable 23 inside the housing 31. Note that the central axis Axc is not limited to this example.

[0041] The linear movement member 52 is spaced apart from the flange 56 in the first axial direction Dx1 and surrounds the first outer peripheral surface 55a of the cylinder wall 55. The linear movement member 52 is supported by the housing 31 so as to be restricted from rotating around the central axis Axc and movable in the axial direction. The linear movement member 52 has an end face 52a, an inner peripheral surface 52b, and a female thread 52c.

[0042] The end face 52a is provided at the end of the linear movement member 52 in the first axial direction Dx1. The inner peripheral surface 52b is a substantially cylindrical curved surface extending along the central axis Axc and facing inward in the radial direction. The female thread 52c is provided on the inner peripheral surface 52b. The linear movement member 52 is attached to the rotating member 51 by the engagement of the female thread 52c and the male thread 55c. Note that a female thread may be formed on the rotating member 51 and a male thread may be formed on the linear movement member 52.

[0043] The bearing 35 is, for example, a ball bearing. The bearing 35 can withstand not only radial loads but also axial loads. Note that the bearing 35 may be other bearings such as roller bearings or bushes, or may be a thrust bearing. The bearing 35 has an inner race 61, an outer race 62, and a plurality of balls 63.

[0044] The inner race 61 and the outer race 62 are formed in a substantially cylindrical shape extending along the central axis Axc. The inner race 61 is attached to the second outer peripheral surface 55b of the cylindrical wall 55 and is supported by the flange 56. The outer race 62 surrounds the inner race 61 and is supported by the housing 31. The plurality of balls 63 are located between the inner race 61 and the outer race 62 and are arranged in the circumferential direction. Thereby, the rotating member 51 is supported by the housing 31 via the bearing 35 so as to be rotatable about the central axis Axc.

[0045] The cable end 36 is attached to the end 23b of the cable 23. The cable end 36 is supported by the end face 52a of the linear movement member 52. That is, the cable 23 is supported by the linear movement member 52 via the cable end 36. Note that the cable end 36 may be temporarily supported by the housing 31, for example.

[0046] When the linear movement member 52 supports the cable end 36, the linear movement member 52 can move the cable 23 in the axial direction via the cable end 36. In other words, the linear movement member 52 can pull or feed out the cable 23.

[0047] The cable 23 is biased in the second axial direction Dx2 by, for example, a spring. Thereby, even if the cable 23 moves in the axial direction, the cable end 36 continues to contact the linear movement member 52, and tension is always generated in the cable 23.

[0048] When the rotation of the output shaft 41 is transmitted to the rotating member 51 via the speed reduction mechanism 33, the rotating member 51 rotates about the central axis Axc. Since the female screw 52c and the male screw 55c mesh with each other, the linear movement member 52 moves in the axial direction in accordance with the rotation of the rotating member 51.

[0049] For example, when the output shaft 41 rotates in one direction, the rotating member 51 rotates so as to move the linear movement member 52 in the first axial direction Dx1. When the end face 52a supports the cable end 36, the linear movement member 52 moves in the first axial direction Dx1, thereby moving the cable 23 in the first axial direction Dx1 via the cable end 36. In other words, the linear movement member 52 pulls the cable 23 in the first axial direction Dx1. The cable 23 pulled by the linear movement member 52 pulls the lever 21, bringing the brake shoes 11R, 11L into contact with the drum rotor 3.

[0050] When the output shaft 41 rotates in the reverse direction, the rotating member 51 rotates so as to move the linear movement member 52 in the second axial direction Dx2. When the linear movement member 52 moves in the second axial direction Dx2, for example, a spring that pulls the cable 23 moves the cable 23 in the second axial direction Dx2. As a result, the tensile force exerted by the cable 23 on the lever 21 is released, and the brake shoes 11R, 11L are separated from the drum rotor 3.

[0051] The guide member 37 is made of, for example, a synthetic resin. The guide member 37 is attached to the housing 31 at a position spaced apart from the cylindrical wall 55 in the second axial direction Dx2. The guide member 37 is formed in a substantially cylindrical shape surrounding the central axis Axc. The guide member 37 guides the cable 23 that moves in the axial direction.

[0052] The pipe seal 38 is, for example, a substantially annular rubber seal. The pipe seal 38 is interposed between the pipe member 25 and the housing 31. The pipe seal 38 seals the gap between the pipe member 25 and the housing 31 and restricts, for example, the entry of liquid into the interior of the housing 31.

[0053] The housing 31 has a lower case 71, an upper case 72, and a plurality of fasteners 73 such as screws. The lower case 71 is an example of a first case. The upper case 72 is an example of a second case.

[0054] The lower case 71 has a metal part 81, a plurality of nuts 82, and a resin part 83. The metal part 81 is an example of a first part and may also be referred to as a sleeve. The resin part 83 is an example of a second part. The metal part 81, the nuts 82, and the resin part 83 are integrally formed, for example, by insert molding.

[0055] The metal part 81 and the nuts 82 are each metal members. The material of the metal part 81 is, for example, cast iron, stainless steel, or an aluminum alloy. The material of the nuts 82 is, for example, stainless steel. Note that the materials of the metal part 81 and the nuts 82 may be other metals.

[0056] The metal part 81 has a cylindrical part 91, a flange part 92, and a plurality of nut parts 93. The cylindrical part 91, the flange part 92, and the nut parts 93 are integrally formed, for example, by die casting or welding. Note that the cylindrical part 91, the flange part 92, and the nut parts 93 are not limited to this example.

[0057] The cylindrical part 91 is formed in a substantially cylindrical shape extending along the central axis Axc. That is, a through hole 95 that penetrates the cylindrical part 91 along the central axis Axc is provided in the cylindrical part 91. The through hole 95 penetrates the metal part 81 and opens to the outside of the metal part 81.

[0058] The cylindrical part 91 has an inner peripheral surface 91a and an outer peripheral surface 91b. The inner peripheral surface 91a and the outer peripheral surface 91b are each a substantially cylindrical curved surface extending along the central axis Axc. The inner peripheral surface 91a faces the inside of the cylindrical part 91 and forms (defines, partitions) the through hole 95. In other words, the inner peripheral surface 91a faces the central axis Axc. The outer peripheral surface 91b is located on the opposite side of the inner peripheral surface 91a and faces radially outward.

[0059] The flange portion 92 protrudes radially outward from the outer peripheral surface 91b at the end of the cylindrical portion 91 in the second axial direction Dx2. The flange portion 92 is provided at the end of the lower case 71 in the second axial direction Dx2.

[0060] The flange portion 92 has a connection surface 92a. The connection surface 92a contacts the backing plate 12. Note that a sealing material may be interposed between the connection surface 92a and the backing plate 12. Further, a plurality of insertion holes 96 are provided in the flange portion 92. The insertion holes 96 penetrate the flange portion 92 and open to the connection surface 92a.

[0061] A plurality of nut portions 93 are attached to the flange portion 92. For example, the nut portion 93 is attached to the surface of the flange portion 92 on the side opposite to the connection surface 92a. A screw hole 97 is provided in each of the plurality of nut portions 93. The screw hole 97 communicates with the corresponding insertion hole 96. The nut portion 93 has a female screw provided in the screw hole 97.

[0062] For example, a bolt passes through the backing plate 12, passes through the insertion hole 96, and is screwed into the screw hole 97. Thereby, the lower case 71 is attached to the backing plate 12. Note that the lower case 71 may be attached to the backing plate 12 by other methods.

[0063] The metal part 81 has an outer surface 81a. The outer surface 81a is the surface of the metal part 81 facing the outside of the braking device 10. For example, the outer peripheral surface 91b of the cylindrical portion 91 faces the outside of the braking device 10 and is included in the outer surface 81a.

[0064] On one side, among the flange portions 92, the connection surface 92a contacts the backing plate 12 and is covered by the backing plate 12, so it does not face the outside of the braking device 10. Therefore, the connection surface 92a is not included in the outer surface 81a. Also, the inner surface of the flange portion 92 that forms the insertion hole 96 faces the inside of the insertion hole 96 and is covered by a bolt, so it is not included in the outer surface 81a. Among the flange portions 92, the surface on the opposite side of the connection surface 92a and the edge of the flange portion 92 face the outside of the braking device 10 and are included in the outer surface 81a.

[0065] Among the nut portions 93, the inner surface that forms the screw hole 97 faces the inside of the screw hole 97 and is covered by a bolt, so it is not included in the outer surface 81a. Among the nut portions 93, the surface on the opposite side of the inner surface that forms the screw hole 97 faces the outside of the braking device 10 and is included in the outer surface 81a.

[0066] The resin portion 83 is the resin - made part of the lower case 71 manufactured by insert molding. The material of the resin portion 83 is a synthetic resin such as plastic, for example. Therefore, the resin portion 83 has lower rigidity and density than each of the metal portion 81 and the nut 82. Note that the rigidity and density of the resin portion 83 are not limited to this example. The resin portion 83 has a main body 101, an inner cylinder portion 102, and an outer cylinder portion 103.

[0067] The main body 101 has a connection surface 101a and a support surface 101b. In other words, the support surface 101b is provided on the resin portion 83. Note that the support surface 101b may be provided on the metal portion 81. The connection surface 101a is provided at the end of the lower case 71 in the first axial direction Dx1. A recess 105 that opens to the connection surface 101a is provided in the main body 101. The recess 105 is recessed from the connection surface 101a in the second axial direction Dx2.

[0068] The main body 101 houses at least partially the bearing 35, the gears 45, 46, 47, the support shaft 48, the rotating member 51, and the linear motion member 52 in the recess 105. For example, the main body 101 houses a portion including the second outer peripheral surface 55b of the cylindrical wall 55 of the rotating member 51 and the flange 56 in the recess 105. Further, the support shaft 48 is fitted into a hole provided in the main body 101 and is supported by the main body 101.

[0069] The support surface 101b is provided in the recess 105. In other words, the support surface 101b is a part of the inner surface of the main body 101 that forms the recess 105. The recess 105 is a substantially annular plane facing in the first axial direction Dx1.

[0070] The support surface 101b axially supports the outer race 62 of the bearing 35. Therefore, the support surface 101b supports the rotating member 51 via the bearing 35. The inner diameter of the support surface 101b is equal to or less than the inner diameter of the outer race 62. The outer diameter of the support surface 101b is equal to or greater than the outer diameter of the outer race 62. The support surface 101b is spaced apart from the inner race 61.

[0071] The metal part 81 is provided between the support surface 101b and the backing plate 12. The cylindrical portion 91 of the metal part 81 surrounds the cable 23 that extends axially through the inside of the bearing 35 and the rotating member 51.

[0072] The diameter of the inner peripheral surface 91a of the cylindrical portion 91 (the inner diameter of the cylindrical portion 91) is smaller than the outer diameter of the support surface 101b. The diameter of the outer peripheral surface 91b of the cylindrical portion 91 (the outer diameter of the cylindrical portion 91) is larger than the inner diameter of the support surface 101b. The cylindrical portion 91 axially overlaps the support surface 101b.

[0073] Among the resin part 83, the portion 83a including the support surface 101b is interposed between the support surface 101b and the end portion 91c of the cylindrical portion 91 in the first axial direction Dx1. The portion 83a covers the end portion 91c of the cylindrical portion 91 and does not expose the metal part 81 in the recess 105.

[0074] A plurality of nuts 82 are embedded in the main body 101. The screw holes of the plurality of nuts 82 open to the connection surface 101a. On the connection surface 101a, the nuts 82 may be covered by the resin portion 83 or may be exposed.

[0075] The inner cylinder portion 102 extends from the main body 101 in the second axial direction Dx2. The inner cylinder portion 102 covers the inner peripheral surface 91a of the cylinder portion 91 over the entire circumferential direction. In other words, the inner cylinder portion 102 is provided in the through hole 95 of the cylinder portion 91 and is formed in a substantially cylindrical shape extending along the central axis Axc. Note that a part of the inner peripheral surface 91a in the axial direction may be exposed without being covered by the inner cylinder portion 102.

[0076] The inner cylinder portion 102 has an inner peripheral surface 102a and a protruding portion 102b. The inner peripheral surface 102a may also be referred to as a sealing surface. The inner peripheral surface 102a is a substantially cylindrical curved surface extending along the central axis Axc and faces the central axis Axc. The protruding portion 102b protrudes radially inward from the end of the inner peripheral surface 102a in the first axial direction Dx1.

[0077] The inner cylinder portion 102 is formed in a substantially cylindrical shape along the inner peripheral surface 91a of the cylinder portion 91. Therefore, a passage 106 is provided inside the inner cylinder portion 102. The inner peripheral surface 102a forms a part of the passage 106. The passage 106 extends along the central axis Axc and communicates with the recess 105.

[0078] The cable 23 extends through the passage 106. The guide member 37 is disposed in the passage 106 and supported by the protruding portion 102b. The pipe member 25 and the pipe seal 38 are accommodated in the passage 106 inside the inner peripheral surface 102a.

[0079] The end of the pipe member 25 in the first axial direction Dx1 abuts against the protruding portion 102b or is spaced apart from the protruding portion 102b in the second axial direction Dx2. The pipe seal 38 contacts the pipe member 25 and the inner peripheral surface 102a and is spaced apart from the metal portion 81.

[0080] The pipe seal 38 seals the gap between the pipe member 25 and the lower case 71 between the pipe member 25 and the inner peripheral surface 102a. In the axial direction, the length of the inner peripheral surface 102a is longer than the length of the portion where the inner peripheral surface 102a contacts the pipe seal 38.

[0081] The outer cylinder part 103 extends from the main body 101 in the second axial direction Dx2. The outer cylinder part 103 covers the outer peripheral surface 91b of the cylinder part 91 over the entire circumferential direction. For this reason, the cylinder part 91 is located between the inner cylinder part 102 and the outer cylinder part 103.

[0082] In the present embodiment, the outer cylinder part 103 covers the entire outer surface 81a of the metal part 81. That is, the outer cylinder part 103 covers not only the cylinder part 91 but also the flange part 92 and the nut part 93. For this reason, in the lower case 71 attached to the backing plate 12, the metal part 81 is not exposed outside the braking device 10.

[0083] The upper case 72 is basically made of a synthetic resin such as plastic. In the example of FIG. 3, the upper case 72 has a plurality of resin members, nuts and sleeves embedded in the plurality of members, and screws for connecting the plurality of members to each other. Note that the upper case 72 is not limited to this example, and may be entirely made of resin or entirely made of metal.

[0084] The upper case 72 has a connection surface 72a. The connection surface 72a is a resin surface. That is, the connection surface 72a is provided on the resin member of the upper case 72. The connection surface 72a is provided at the end of the upper case 72 in the second axial direction Dx2.

[0085] The connection surface 72a of the upper case 72 and the connection surface 101a of the main body 101 of the lower case 71 face each other. The two connection surfaces 72a, 101a are sealed between them, for example, by contacting each other or by interposing a sealer or sealing material between the two connection surfaces 72a, 101a. The sealing material is, for example, a silicone resin, synthetic rubber, or gasket. The upper case 72 is separated from the metal part 81.

[0086] The upper case 72 is provided with a recess 111 and a plurality of insertion holes 112. The recess 111 opens to the connection surface 72a. The recess 111 is recessed from the connection surface 72a in the first axial direction Dx1. The upper case 72 at least partially houses the motor 32, the cable end 36, the gear 45, the support shaft 48, the rotating member 51, and the linear motion member 52 in the recess 111.

[0087] The insertion hole 112 is a through hole that opens to the connection surface 72a. The insertion hole 112 communicates with the screw hole of the nut 82 of the lower case 71. The fastener 73 is screwed into the screw hole of the nut 82 through the insertion hole 112 to attach the upper case 72 to the lower case 71.

[0088] The recess 105 and the passage 106 of the lower case 71 and the recess 111 of the upper case 72 form the internal space S of the housing 31. The housing 31 houses the other end 23b of the cable 23, the motor 32, the speed reduction mechanism 33, the motion conversion mechanism 34, the bearing 35, the cable end 36, the guide member 37, and the pipe seal 38 in the internal space S. That is, the upper case 72 houses the rotating member 51 and the linear motion member 52 together with the lower case 71.

[0089] When the linear motion member 52 pulls the cable 23 in the first axial direction Dx1, a reaction force acts on the linear motion member 52. The reaction force acts on the support surface 101b of the lower case 71 via the linear motion member 52, the rotating member 51, and the bearing 35. The support surface 101b receives the load in the second axial direction Dx2 as the reaction force.

[0090] A metal part 81 is provided between a support surface 101b that receives a reaction force and a backing plate 12 to which a lower case 71 is attached. The cylindrical portion 91 extends in substantially the same direction (axial direction) as a second axial direction Dx2 in which the reaction force acts on the support surface 101b. For this reason, between the support surface 101b and the backing plate 12, the lower case 71 can obtain a strength (rigidity) capable of withstanding the reaction force. In other words, the metal part 81 reinforces the lower case 71 between the support surface 101b and the backing plate 12.

[0091] The pipe seal 38 restricts liquid from entering the internal space S of the housing 31. When the pipe seal 38 is in contact with metal, in order to prevent a liquid such as rainwater, which causes corrosion of the metal, from touching the metal with which the pipe seal 38 is in contact, for example, measures such as installation considering the up-and-down orientation are taken. However, the pipe seal 38 is in contact with the inner cylindrical portion 102 of the resin part 83. For this reason, the braking device 10 suppresses a gap from being generated between the pipe seal 38 and the lower case 71 due to expansion of the metal caused by corrosion.

[0092] The connection surface 72a of the upper case 72, together with the connection surface 101a of the lower case 71, seals the space between the two connection surfaces 72a, 101a and restricts liquid from entering the internal space S of the housing 31. If the connection surfaces 72a, 101a are made of metal, in order to prevent a liquid such as rainwater, which causes corrosion of the metal, from touching the metal, for example, measures such as applying a sealer are taken. However, the connection surfaces 72a, 101a are made of resin. For this reason, the braking device 10 suppresses a gap from being generated between the lower case 71 and the upper case 72 due to expansion of the metal caused by corrosion.

[0093] Among the internal space S of the housing 31, inside the pipe seal 38, the resin portion 83 covers the entire area of the metal portion 81. For example, the end 91c of the cylindrical portion 91 is also covered by the resin portion 83. Therefore, even if the metal portion 81 corrodes, the braking device 10 suppresses the corrosion from progressing to the internal space S or the occurrence of a gap communicating the internal space S with the outside due to the expansion of the metal caused by the corrosion.

[0094] In the braking device 10 according to the present embodiment described above, the brake shoe 11 is configured to brake the wheel 2 by contacting the drum rotor 3 that rotates integrally with the wheel 2, and is supported by the backing plate 12. The rotating member 51 is rotatable about the central axis Axc. The linear motion member 52 is attached to the rotating member 51 so as to move in the axial direction along the central axis Axc in response to the rotation of the rotating member 51. The cable 23 is supported by the linear motion member 52 and is configured to bring the brake shoe 11 into contact with the drum rotor 3 by being pulled by the linear motion member 52. The lower case 71 is attached to the backing plate 12 and has a support surface 101b, a metal portion 81, and a resin portion 83. The support surface 101b supports the rotating member 51. The metal portion 81 is provided between the support surface 101b and the backing plate 12 and surrounds the cable 23. The resin portion 83 is formed integrally with the metal portion 81 and at least partially houses the rotating member 51.

[0095] When the linear motion member 52 pulls the cable 23, the reaction force of the cable 23 acts on the support surface 101b via the linear motion member 52 and the rotating member 51. The lower case 71 can obtain a strength capable of withstanding the reaction force by providing a metal metal portion 81 between the support surface 101b and the backing plate 12. On the other hand, the lower case 71 has a resin portion 83 as a portion that houses the rotating member 51 where the reaction force hardly acts. Generally, the density of resin is smaller than that of metal. Thereby, the braking device 10 can be weight-reduced compared to the case where the entire lower case 71 is made of metal, and thus the cost can be reduced.

[0096] The upper case 72 has a resin connection surface 72a that seals the space between it and the resin part 83 together with the resin part 83. The upper case 72 is spaced apart from the metal part 81 and is attached to the lower case 71 so as to accommodate the rotating member 51 and the linear motion member 52 together with the lower case 71. That is, the resin part 83 of the lower case 71 and the resin connection surface 72a of the upper case 72 seal the space between the resin part 83 and the connection surface 72a. Thereby, the braking device 10 can suppress the occurrence of a gap due to, for example, corrosion of the metal between the lower case 71 and the connection surface 72a of the upper case 72, and thus can more reliably maintain the sealing between the lower case 71 and the upper case 72.

[0097] The pipe member 25 surrounds the cable 23. The pipe seal 38 contacts the resin part 83, is spaced apart from the metal part 81, and seals the space between the lower case 71 and the pipe member 25. That is, the resin part 83 of the lower case 71 and the pipe seal 38 contact each other. Thereby, the braking device 10 can suppress the formation of a gap at the portion (inner peripheral surface 102a) where the lower case 71 and the pipe seal 38 contact due to, for example, corrosion of the metal, and thus can more reliably maintain the sealing between the lower case 71 and the pipe seal 38.

[0098] The metal part 81 has an outer surface 81a facing the outside of the braking device 10. The resin part 83 covers the entire area of the outer surface 81a. The resin part 83 protects the outer surface 81a of the metal part 81 and can suppress the metal part 81 from being exposed to the outside of the braking device 10. Thereby, the braking device 10 can suppress the corrosion of the metal part 81, and thus can more reliably maintain the sealing by the lower case 71.

[0099] The support surface 101b is provided on the resin portion 83. By providing the support surface 101b on the resin portion 83, the metal portion 81 is separated from the rotating member 51 or a component such as the bearing 35 interposed between the rotating member 51 and the support surface 101b. That is, in the portion of the internal space S of the housing 31 that is inside the pipe seal 38 and includes the support surface 101b, the resin portion 83 covers the entire area of the metal portion 81. For this reason, even if the metal portion 81 corrodes, the brake device 10 suppresses the corrosion from progressing to the internal space S or a gap communicating the internal space S with the outside being generated due to the expansion of the metal caused by the corrosion. Further, since the support surface 101b is made of resin, for example, it is possible to suppress expansion due to corrosion, and thus it is possible to suppress displacement of the rotating member 51 from a desired position.

[0100] The braking device according to at least one embodiment described above is configured, as an example, to brake the wheel by contacting a drum rotor that rotates integrally with the wheel, and includes a braking member supported by the backing plate, a rotating member rotatable about a central axis, a linear motion member attached to the rotating member so as to move in an axial direction along the central axis in response to the rotation of the rotating member, a cable supported by the linear motion member and configured to contact the braking member with the drum rotor by being pulled by the linear motion member, a support surface attached to the backing plate and supporting the rotating member, a first metal portion provided between the support surface and the backing plate and surrounding the cable, and a second resin portion formed integrally with the first portion and at least partially accommodating the rotating member. Thus, as an example, when the linear motion member pulls the cable, the reaction force of the cable acts on the support surface via the linear motion member and the rotating member. The first case can obtain strength capable of withstanding the reaction force by providing the first metal portion between the support surface and the backing plate. On the other hand, the first case has a second resin portion as a portion for accommodating the rotating member on which the reaction force hardly acts. Generally, resin has a lower density than metal. As a result, the braking device can be made lighter and, consequently, the cost can be reduced compared to the case where the entire first case is made of metal.

[0101] The braking device, as an example, has a resin connection surface that seals the space between the second part and itself, is spaced apart from the first part, and is attached to the first case so as to accommodate the rotating member and the linear moving member together with the first case, and further includes a second case. Thus, as an example, as described above, the resin second part of the first case, the resin connection surface of the second case, and the space between the second part and the connection surface are sealed. Thereby, the braking device can suppress the occurrence of a gap due to, for example, corrosion of the metal between the connection surfaces of the first case and the second case, and thus can more reliably maintain the sealing between the first case and the second case.

[0102] The braking device, as an example, further includes a pipe member that surrounds the cable, and a seal member that contacts the second part, is spaced apart from the first part, and seals the space between the first case and the pipe member. Thus, as an example, as described above, the resin second part of the first case and the seal member contact each other. Thereby, the braking device can suppress the formation of a gap due to, for example, corrosion of the metal at the part where the first case and the seal member contact, and thus can more reliably maintain the sealing between the first case and the seal member.

[0103] In the braking device, as an example, the first part has an outer surface facing the outside of the braking device, and the second part covers the entire area of the outer surface. Thus, as an example, the resin second part protects the outer surface of the metal first part and can suppress the first part from being exposed to the outside of the braking device. Thereby, the braking device can suppress the first part from corroding, and thus can more reliably maintain the sealing by the first case.

[0104] In the above-described braking device, as an example, the support surface is provided on the second portion. Thus, as an example, by providing the support surface on the second portion, the metal first portion is separated from a rotating member or a component such as a bearing interposed between the rotating member and the support surface. That is, in the internal space that is at least partially formed by the first case and houses various components such as a rotating member, in the portion including the support surface, the resin second portion can cover the entire area of the metal first portion. For this reason, even if the first portion is corroded, the braking device can suppress the corrosion from progressing to the internal space or the generation of a gap that communicates the internal space with the outside due to the expansion of the metal caused by the corrosion. Further, since the support surface is made of resin, for example, it is possible to suppress expansion due to corrosion, and thus it is possible to suppress displacement of the rotating member from a desired position.

[0105] As described above, the embodiments of the present invention have been illustrated. However, the above embodiments and modified examples are merely examples and are not intended to limit the scope of the invention. The above embodiments and modified examples can be implemented in various other forms, and various omissions, replacements, combinations, and changes can be made without departing from the gist of the invention. Also, the configurations and shapes of each embodiment and each modified example can be partially interchanged and implemented.

Description of Reference Numerals

[0106] 10... Braking device, 11, 11L, 11R... Brake shoe (braking member), 12... Backing plate, 23... Cable, 25... Pipe member, 38... Pipe seal (sealing member), 51... Rotating member, 52... Linear motion member, 71... Lower case (first case), 72... Upper case (second case), 72a... Connection surface, 81... Metal portion (first portion), 81a... Outer surface, 83... Resin portion (second portion), Axc... Central axis.

Claims

1. A backing plate, a braking member configured to brake the wheel by contacting a drum rotor that rotates integrally with the wheel, and supported by the backing plate, a rotating member rotatable about a central axis, a linear motion member attached to the rotating member so as to move in an axial direction along the central axis in response to the rotation of the rotating member, a cable supported by the linear motion member and configured to bring the braking member into contact with the drum rotor by being pulled by the linear motion member, a first case attached to the backing plate, having a support surface for supporting the rotating member, a first metal part provided between the support surface and the backing plate and surrounding the cable, and a second resin part formed integrally with the first part and at least partially accommodating the rotating member, A braking device comprising the above.

2. A second case having a resin connection surface for sealing between the second part and the second part itself, spaced apart from the first part, and attached to the first case so as to accommodate the rotating member and the linear motion member together with the first case. The braking device according to Claim 1, further comprising the above.

3. A pipe member surrounding the cable, A sealing member that contacts the second part, is spaced apart from the first part, and seals between the first case and the pipe member. The braking device according to Claim 1, further comprising the above.

4. The first part has an outer surface facing the outside of the braking device, The second part covers the entire area of the outer surface. The braking device according to Claim 1.

5. The support surface is provided on the second part. The braking device according to Claim 1.

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