Brake caliper

Abstract

An example of a brake caliper according to an embodiment of the present invention comprises: a caliper body having two side walls which are separated from each other in the axial direction along the rotation axis of a disk rotor and a connection wall which connects the two side walls; a pin extending in the axial direction from at least one of the two side walls between the two side walls; and a brake pad located between the two side walls and supported by the pin so as to be movable in the axial direction. The connection wall is configured to restrict the brake pad from moving in a first circumferential direction around the rotation axis by supporting the brake pad via the pin between the two side walls.

Description

Brake caliper

[0001] An embodiment of the present invention relates to a brake caliper.

[0002] Conventionally, a brake caliper including a pair of brake pads, a caliper body provided across a disc rotor, and pins protruding from the caliper body to support the brake pads is known.

[0003] The pins are fixed to the caliper body and guide the brake pads. During braking, the brake pads are supported by the caliper body via the pins while being pressed against the disc rotor. Thereby, the brake caliper brakes the disc rotor (Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2008-116008

[0005] However, in the conventional configuration, during braking, the brake pads push the pins, causing bending stress in the pins. If the pins are thickened to withstand the bending stress, the brake caliper becomes larger.

[0006] Therefore, the present invention has been made in view of the above, and provides a brake caliper capable of making the pins thinner.

[0007] A brake caliper according to an embodiment of the present invention includes, as an example, a caliper body having two side walls spaced apart from each other in the axial direction along the rotation axis of a disc rotor, and a connecting wall connecting the two side walls; a pin extending in the axial direction from at least one of the two side walls between the two side walls; and a brake pad located between the two side walls and supported by the pin so as to be movable in the axial direction, wherein the connecting wall is configured to restrict the movement of the brake pad in a first circumferential direction around the rotation axis by supporting the brake pad via the pin between the two side walls. Thus, as an example, when the brake pad contacts a disc rotor rotating in a first circumferential direction, a first circumferential force acts on the brake pad due to friction. The brake caliper brakes the disc rotor by supporting the brake pad via the pin through the connecting wall. That is, the connecting wall supports the pin during braking. The brake pad acts a first circumferential bending moment on the pin extending axially from the side wall. However, since the connecting wall supports the pin between the two side walls, it can prevent or reduce bending stress on the pin. Therefore, the brake caliper does not need to make the pin thicker due to bending stress during braking, and the pin can be made thinner.

[0008] Figure 1 is a perspective view showing a disc brake device according to one embodiment. Figure 2 is a cross-sectional view showing the disc brake device of the above embodiment. Figure 3 is a schematic cross-sectional view showing a part of the disc brake device of the above embodiment along the line F3-F3 in Figure 2. Figure 4 is a perspective view showing the caliper body of the above embodiment. Figure 5 is a cross-sectional view showing a part of the disc brake device of the above embodiment. Figure 6 is a cross-sectional view showing a part of the brake caliper during braking in the above embodiment.

[0009] An embodiment will be described below with reference to Figures 1 to 6. Note that in this specification, the components of an embodiment and their descriptions may be described using multiple expressions. 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 using expressions different from those used herein.

[0010] 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.

[0011] Figure 1 is a perspective view showing a disc brake device 10 according to this embodiment. The disc brake device 10 is mounted on a vehicle 1 such as a four-wheeled automobile. Note that the disc brake device 10 is not limited to this example.

[0012] Figure 2 is a cross-sectional view showing the disc brake device 10 of this embodiment. As shown in Figure 2, the disc brake device 10 has a disc rotor 11 and a brake caliper 12. The disc rotor 11 may also be referred to as a rotor.

[0013] The disc rotor 11 rotates integrally with the wheel of the vehicle 1 around a central axis Ax. The central axis Ax is an example of a rotation axis. The central axis Ax is, for example, the central axis of the axle, the central axis of the disc rotor 11, and the central axis of rotation of the disc rotor 11. Note that the central axis Ax is not limited to this example.

[0014] For convenience, the following definitions apply to axial, radial, and circumferential directions. The axial direction is the direction along the central axis Ax. The radial direction is the direction perpendicular to the central axis Ax. The circumferential direction is the direction around the central axis Ax.

[0015] The circumferential direction includes the forward rotation direction Dcn and the reverse rotation direction Dcr. The forward rotation direction Dcn is one direction around the central axis Ax and is an example of the first circumferential direction. The reverse rotation direction Dcr is the opposite direction to the forward rotation direction Dcn and is an example of the second circumferential direction. When the vehicle 1 moves forward, the disc rotor 11 rotates in the forward rotation direction Dcn. On the other hand, when the vehicle 1 moves backward, the disc rotor 11 rotates in the reverse rotation direction Dcr.

[0016] The disc rotor 11 is formed in a disc shape that is substantially perpendicular to the central axis Ax. A hat-shaped portion, for example, which is substantially cylindrical, is provided in the center of the disc rotor 11. The disc rotor 11 is coupled to the axle of the vehicle 1 at this hat-shaped portion.

[0017] As shown in Figure 1, the brake caliper 12 in this embodiment is an opposing caliper and is positioned to straddle the disc rotor 11. As shown in Figures 1 and 2, the brake caliper 12 has a caliper body 21, six pistons 22, a pair of first brake pads 23, a pair of second brake pads 24, three pad pins 25, 26, and 27, and a restraining spring 28.

[0018] The first brake pad 23 is an example of a brake pad. The brake caliper 12 may have more brake pads, or it may have a pair of brake pads instead of the pair of first brake pads 23 and the pair of second brake pads 24. The pad pin 25 is an example of a pin.

[0019] The caliper body 21 is made of metal, for example, by casting. However, the caliper body 21 may be made of other materials and by other methods. The caliper body 21 has an inner housing 31, an outer housing 32, and three bridges 33, 34, and 35. The inner housing 31 and the outer housing 32 are examples of side walls. The inner housing 31 is an example of a first side wall. The outer housing 32 is an example of a second side wall. The bridge 33 is an example of a connecting wall.

[0020] The inner housing 31 and the outer housing 32 are spaced apart from each other in the axial direction. The inner housing 31 is positioned inside the outer housing 32 in the vehicle width direction of the vehicle 1. The inner housing 31 is fixed to a non-rotating part of the vehicle 1. For example, the inner housing 31 is attached to the knuckle of the vehicle 1.

[0021] The disc rotor 11 is positioned between the inner housing 31 and the outer housing 32. The inner housing 31 and the outer housing 32 cover a portion of the disc rotor 11 in the axial direction.

[0022] Figure 3 is a schematic cross-sectional view showing a part of the disc brake device 10 of this embodiment along the line F3-F3 in Figure 2. As shown in Figure 3, the inner housing 31 has an inner surface 31a. The outer housing 32 has an inner surface 32a. The inner surfaces 31a and 32a are formed to be substantially flat and are oriented substantially in the axial direction as a whole. The inner surfaces 31a and 32a face each other with a gap between them.

[0023] Three cylinders 38 are provided in both the inner housing 31 and the outer housing 32. The cylinders 38 of the inner housing 31 are recessed in the axial direction from the inner surface 31a. The cylinders 38 of the outer housing 32 are recessed in the axial direction from the inner surface 32a.

[0024] The three cylinders 38 of the inner housing 31 are spaced apart from each other in the circumferential direction. The three cylinders 38 of the outer housing 32 are also spaced apart from each other in the circumferential direction. Each of the cylinders 38 houses a corresponding piston 22 so that it can move in the axial direction.

[0025] As shown in Figure 2, the inner housing 31 is provided with three holes 41, 42, and 43. Hole 41 is an example of a first hole. The three holes 41, 42, and 43 are spaced radially outward from the disc rotor 11. The three holes 41, 42, and 43 are spaced circumferentially from each other. In the circumferential direction, hole 43 is located between the two holes 41 and 42. Hole 41 is spaced apart from hole 43 in the forward rotation direction Dcn.

[0026] The three holes 41, 42, and 43 each penetrate the inner housing 31 in the axial direction. At least one of the three holes 41, 42, and 43 may be a recess opening into the inner surface 31a.

[0027] Figure 4 is a perspective view showing the caliper body 21 of this embodiment. As shown in Figure 4, the outer housing 32 is provided with three holes 45, 46, and 47. Hole 45 is an example of a second hole.

[0028] The three holes 45, 46, and 47 are spaced radially outward from the disc rotor 11. The three holes 45, 46, and 47 are spaced circumferentially from each other. In the circumferential direction, hole 47 is located between the two holes 45 and 46. Hole 45 is spaced apart from hole 47 in the forward rotation direction Dcn.

[0029] Holes 41, 42, 43, 45, 46, and 47 are circular holes with approximately equal diameters. Holes 41 and 45 are arranged coaxially. Holes 42 and 46 are arranged coaxially. Holes 43 and 47 are arranged coaxially. Note that holes 41, 42, 43, 45, 46, and 47 are not limited to this example. For example, at least one of holes 41, 42, 43, 45, 46, and 47 may be elliptical.

[0030] The three holes 45, 46, and 47 each penetrate the outer housing 32 in the axial direction. At least one of the three holes 45, 46, and 47 may be a recess opening into the inner surface 32a.

[0031] As shown in Figure 3, the inner housing 31 further has an inner surface 41a that defines the hole 41. The outer housing 32 further has an inner surface 45a that defines the hole 45. The inner surfaces 41a and 45a are each substantially cylindrical curved surfaces that extend in the axial direction. Note that the inner surfaces 41a and 45a are not limited to this example and may be formed into other shapes, such as substantially elliptical cylindrical curved surfaces.

[0032] As shown in Figure 4, bridges 33, 34, and 35 each extend substantially axially between the inner housing 31 and the outer housing 32, connecting the inner housing 31 and the outer housing 32. Bridges 33, 34, and 35 are spaced radially outward from the disc rotor 11.

[0033] The three bridges 33, 34, and 35 are spaced apart from each other in the circumferential direction. In the circumferential direction, bridge 35 is located between the two bridges 33 and 34. Bridge 33 is spaced apart from bridge 35 in the forward rotation direction Dcn.

[0034] Bridge 33 connects the end of the inner housing 31 to the end of the outer housing 32 in the forward rotation direction Dcn. Bridge 34 connects the end of the inner housing 31 to the end of the outer housing 32 in the reverse rotation direction Dcr.

[0035] Bridge 35 connects the approximately central portion of the inner housing 31 and the approximately central portion of the outer housing 32 in the circumferential direction. Holes 43 and 47 are located between the two bridges 34 and 35 in the circumferential direction.

[0036] Figure 5 is a cross-sectional view showing a part of the disc brake device 10 of this embodiment. As shown in Figure 5, the bridge 33 has an end 51 in the reverse direction Dcr and a concave surface 52. The concave surface 52 is an example of a first concave surface.

[0037] The concave surface 52 is recessed in the forward rotation direction Dcn from the end 51. The concave surface 52 has a substantially semi-cylindrical curved surface 52a that extends in the axial direction. The curved surface 52a may also be a substantially elliptical cylindrical curved surface that extends in the axial direction. The concave surface 52 may also have other surfaces.

[0038] As shown in Figure 4, the bridge 33 is provided with a notch 55 and a recess 56. The recess 52 defines the notch 55. The notch 55 is recessed in the forward rotation direction Dcn from the end 51. The notch 55 communicates with the holes 41 and 45.

[0039] As shown in FIG. 5, the holes 41 and 45, the inner surfaces 41a and 45a, the curved surface 52a, and the notch 55 are coaxially arranged. Further, the radii of the holes 41 and 45, the inner surfaces 41a and 45a, the curved surface 52a, and the notch 55 are substantially equal to each other. For this reason, the curved surface 52a is located between the inner surface 41a and the inner surface 45a and is continuous with the inner surface 41a and the inner surface 45a. Note that the holes 41 and 45, the inner surfaces 41a and 45a, the curved surface 52a, and the notch 55 are not limited to this example.

[0040] As shown in FIG. 3, the recess 56 is recessed in the forward rotation direction Dcn from substantially the center of the concave surface 52 in the axial direction. In the axial direction, the length (width) of the recess 56 is shorter than the length (thickness) of the disk rotor 11. Note that the recess 56 may be omitted.

[0041] As shown in FIG. 2, the bridge 33 and the bridge 34 are formed substantially mirror symmetric in the circumferential direction. For this reason, the bridge 34 also has an end portion 51, a concave surface 52, and a curved surface 52a, and the notch 55 and the recess 56 are provided. Note that the bridge 34 is not limited to this example.

[0042] As shown in FIG. 3, the pair of first brake pads 23 are located between the inner housing 31 and the outer housing 32 and are spaced apart from each other in the axial direction. The disk rotor 11 is disposed between the pair of first brake pads 23.

[0043] The pair of first brake pads 23 are formed substantially mirror symmetric in the axial direction. Note that the pair of first brake pads 23 may have different shapes from each other. Each of the pair of first brake pads 23 has a back plate 61, a friction material 62, and a shim 63.

[0044] The back plate 61 is arranged so as to be substantially orthogonal to the central axis Ax and is formed in a plate shape extending substantially in the circumferential direction. The back plate 61 has a mounting surface 61a and a back surface 61b. Each of the mounting surface 61a and the back surface 61b is formed substantially flat and faces in the axial direction.

[0045] The mounting surface 61a faces the disk rotor 11. The back surface 61b is located on the opposite side of the mounting surface 61a. In the first brake pad 23 positioned between the disk rotor 11 and the inner housing 31, the back surface 61b faces the inner surface 31a of the inner housing 31. In the first brake pad 23 positioned between the disk rotor 11 and the outer housing 32, the back surface 61b faces the inner surface 32a of the outer housing 32. Further, the back surface 61b faces the piston 22.

[0046] As shown in FIG. 2, the back plate 61 further has an inner edge 61c and an outer edge 61d. The inner edge 61c is the edge of the back plate 61 on the inner side in the radial direction. The inner edge 61c faces the inner side in the radial direction. The outer edge 61d is located on the opposite side of the inner edge 61c. The outer edge 61d is the edge of the back plate 61 on the outer side in the radial direction. The outer edge 61d faces the outer side in the radial direction.

[0047] The back plate 61 further has two protrusions 71, 72. The protrusion 71 protrudes radially outward from the vicinity of the end of the outer edge 61d in the forward rotation direction Dcn. The protrusion 72 protrudes radially outward from the end of the outer edge 61d in the reverse rotation direction Dcr.

[0048] As shown in FIG. 5, the protrusion 71 has an end 75 and a concave surface 76 in the forward rotation direction Dcn. The concave surface 76 is an example of a second concave surface. The concave surface 76 is recessed from the end 75 in the reverse rotation direction Dcr. The concave surface 76 faces the concave surface 52 of the bridge 33. The concave surface 76 is formed in a substantially L shape and has a first plane 76a and a second plane 76b.

[0049] The first plane 76a and the second plane 76b are each formed substantially flat. The first plane 76a faces, for example, a diagonal direction (lower left in FIG. 5) between the forward rotation direction Dcn and the inner side in the radial direction. The second plane 76b faces, for example, a diagonal direction (upper left in FIG. 5) between the forward rotation direction Dcn and the outer side in the radial direction.

[0050] The first plane 76a and the second plane 76b extend in the reverse direction Dcr such that the distance between them tapers. The ends of the first plane 76a and the ends of the second plane 76b in the reverse direction Dcr are connected to each other. The angle between the first plane 76a and the second plane 76b is, for example, approximately 90°. Note that the angle between the first plane 76a and the second plane 76b is not limited to this example.

[0051] A notch 78 is provided in the projection 71. The concave surface 76 defines the notch 78. The notch 78 is recessed in the reverse direction Dcr from the end 75. The notch 78 opens to the mounting surface 61a, the back surface 61b, and the end 75. The notch 78 tapers toward the reverse direction Dcr.

[0052] As shown in Figure 2, a notch 79 is provided in the projection 72. The notch 79 is recessed from the end of the projection 72 in the reverse direction Dcr to the forward direction Dcn. The notch 79 opens on the mounting surface 61a, the back surface 61b, and the end of the projection 72 in the reverse direction Dcr.

[0053] The friction material 62 is fixed to the mounting surface 61a of the back plate 61. As shown in Figure 3, the friction material 62 is located between the mounting surface 61a and the disc rotor 11. The shim 63 is attached to the back surface 61b of the back plate 61.

[0054] As shown in Figure 1, the pair of second brake pads 24 are located between the inner housing 31 and the outer housing 32, spaced apart from each other in the axial direction. The disc rotor 11 is positioned between the pair of second brake pads 24.

[0055] The first brake pad 23 and the second brake pad 24 are arranged circumferentially with a gap between them. The second brake pad 24 is spaced apart from the first brake pad 23 in the reverse direction Dcr. In the circumferential direction, the second brake pad 24 is shorter than the first brake pad 23.

[0056] The pair of second brake pads 24 are formed to be substantially mirror-symmetric in the axial direction. The pair of second brake pads 24 may have different shapes. As shown in Figure 2, each of the pair of second brake pads 24 has a back plate 81 and a friction material 82. The second brake pads 24 also have shims, similar to the first brake pads 23.

[0057] The back plate 81 is positioned approximately perpendicular to the central axis Ax and is formed in a plate shape that extends approximately circumferentially. The back plate 81 has a mounting surface 81a. The mounting surface 81a is formed to be approximately flat and faces axially. The mounting surface 81a faces the disc rotor 11. The friction material 82 is fixed to the mounting surface 81a of the back plate 81. The friction material 82 is located between the mounting surface 81a and the disc rotor 11.

[0058] The backplate 81 further has an inner edge 81c and an outer edge 81d. The inner edge 81c is the edge of the backplate 81 on the radially inner side. The inner edge 81c faces radially inward. The outer edge 81d is located on the opposite side of the inner edge 81c. The outer edge 81d is the edge of the backplate 81 on the radially outer side. The outer edge 81d faces radially outward.

[0059] The backplate 81 further has two projections 91 and 92. Projection 91 protrudes radially outward from near the end of the outer edge 81d in the reverse direction Dcr. Projection 92 protrudes radially outward from the end of the outer edge 81d in the forward direction Dcn.

[0060] The projection 91 has an end portion 95 in the reverse direction Dcr and a concave surface 96. The concave surface 96 is recessed from the end portion 95 in the forward direction Dcn. The concave surface 96 faces the concave surface 52 of the bridge 34. The concave surface 96 is formed in a substantially L-shape.

[0061] A notch 98 is provided in the projection 91. The concave surface 96 defines the notch 98. The notch 98 is recessed in the forward rotation direction Dcn from the end 95. The notch 98 opens to the mounting surface 81a and the end 95. The recess 98 tapers toward the forward rotation direction Dcn.

[0062] A notch 99 is provided in the projection 92. The notch 99 is recessed in the reverse direction Dcr from the end of the projection 92 in the forward direction Dcn. The notch 99 opens at the mounting surface 81a and at the end of the projection 92 in the reverse direction Dcr.

[0063] The pad pins 25, 26, and 27 are each made of a metal such as stainless steel and are formed in a roughly cylindrical shape that extends in the axial direction. However, the pad pins 25, 26, and 27 may be made of other materials or formed in other shapes.

[0064] As shown in Figure 3, the pad pin 25 extends axially through holes 41 and 45 and the notch 55 of the bridge 33. Therefore, the pad pin 25 is spaced radially outward from the disc rotor 11. The pad pin 25 extends axially from the inner housing 31 and the outer housing 32 between the inner housing 31 and the outer housing 32.

[0065] The radius of the pad pin 25 is smaller than the radius of hole 41, smaller than the radius of hole 45, and smaller than the radius of the curved surface 52a. In other words, the width of the pad pin 25 around its central axis Ax is smaller than that of hole 41 and hole 45, respectively.

[0066] The pad pin 25 is movable in the circumferential and radial directions within the holes 41 and 45. That is, the pad pin 25 is fitted into the holes 41, 45, and notch 55 so as to be movable around the central axis Ax.

[0067] The pad pin 25 has an outer circumferential surface 25a. The outer circumferential surface 25a is a substantially cylindrical curved surface that extends in the axial direction. The outer circumferential surface 25a is supported by the inner surface 41a of the inner housing 31 and the inner surface 45a of the outer housing 32. The pad pin 25 may be temporarily separated from at least one of the inner surfaces 41a and 45a.

[0068] Two locking parts 101 are attached to the pad pin 25. The locking parts 101 are, for example, C-rings (C-type retaining rings). However, the locking parts 101 may be various other parts such as E-rings (E-type retaining rings), screws, or rivets.

[0069] The two locking components 101 are attached to the pad pin 25 outside the caliper body 21 in the axial direction. In other words, the caliper body 21 is located between the two locking components 101.

[0070] Each of the two locking parts 101 protrudes from the outer circumferential surface 25a of the pad pin 25. The outer diameter of the locking part 101 is larger than the diameter of hole 41 and larger than the diameter of hole 45. Therefore, the two locking parts 101 restrict the axial movement of the pad pin 25 relative to the caliper body 21, and consequently prevent the pad pin 25 from coming out of holes 41 and 45. The axial movement of the pad pin 25 relative to the caliper body 21 may be restricted by other methods, such as crimping.

[0071] As shown in Figure 5, the pad pin 25 also fits into the notch 78 of the first brake pad 23. The first plane 76a of the concave surface 76 contacts the pad pin 25, thereby restricting the first brake pad 23 from moving closer to the central axis Ax. The second plane 76b of the concave surface 76 contacts the pad pin 25, thereby restricting the first brake pad 23 from moving away from the central axis Ax.

[0072] The concave surface 76 of the first brake pad 23 is supported by a pad pin 25 so that the first brake pad 23 can move in the axial direction. The pad pin 25 may be temporarily separated from the concave surface 76.

[0073] As shown in Figure 1, the pad pin 26 extends axially through holes 42 and 46 and the notch 55 of the bridge 34. Therefore, the pad pin 26 is spaced radially outward from the disc rotor 11. The pad pin 26 extends axially from the inner housing 31 and the outer housing 32 between the inner housing 31 and the outer housing 32.

[0074] The radius of the pad pin 26 is smaller than the radius of hole 42, smaller than the radius of hole 46, and smaller than the radius of the curved surface 52a. In other words, the width of the pad pin 26 around its central axis Ax is smaller than that of hole 42 and hole 46, respectively.

[0075] The pad pin 26 is movable in the circumferential and radial directions within the holes 42 and 46. That is, the pad pin 26 is fitted into the holes 42, 46 and the notch 55 so as to be movable around the central axis Ax.

[0076] The pad pin 26 is supported by the inner housing 31 and the outer housing 32. The pad pin 25 may be temporarily separated from at least one of the inner housing 31 and the outer housing 32.

[0077] The pad pin 26 is restricted from axial movement relative to the caliper body 21 by a locking component, such as a C-ring. The pad pin 26 may also be restricted from axial movement relative to the caliper body 21 by other means.

[0078] As shown in Figure 2, the pad pin 26 also fits into the notch 98 of the second brake pad 24. The concave surface 96 of the second brake pad 24 is supported by the pad pin 26 so that the second brake pad 24 can move in the axial direction. The pad pin 26 may be temporarily separated from the concave surface 96.

[0079] As shown in Figure 1, the pad pin 27 extends axially through holes 43 and 47. Therefore, the pad pin 27 is spaced radially outward from the disc rotor 11. The pad pin 27 extends axially from the inner housing 31 and the outer housing 32 between the inner housing 31 and the outer housing 32.

[0080] The radius of the pad pin 27 is smaller than the radius of the hole 43 and also smaller than the radius of the hole 47. The pad pin 27 is movable in the circumferential and radial directions within the holes 43 and 47. That is, the pad pin 27 is fitted into the holes 43 and 47 so as to be movable around the central axis Ax. Note that the pad pin 27 is not limited to this example and may be fixed to the caliper body 21.

[0081] As shown in Figure 2, the pad pin 27 fits into the notch 79 of the first brake pad 23 and the notch 99 of the second brake pad 24. The first brake pad 23 and the second brake pad 24 are each supported by the pad pin 27 so as to be movable in the axial direction. The first brake pad 23 and the second brake pad 24 may be temporarily separated from the pad pin 27.

[0082] As shown in Figure 1, the restraining spring 28 is located between the inner housing 31 and the outer housing 32. The restraining spring 28 is, for example, a leaf spring. However, the restraining spring 28 may be any other type of spring. The restraining spring 28 contacts, for example, the pad pin 27, the pair of first brake pads 23, and the pair of second brake pads 24.

[0083] The restraining spring 28 is supported by the caliper body 21 via the pad pin 27. The restraining spring 28 pushes the pair of first brake pads 23 and the pair of second brake pads 24 toward the central axis Ax. For example, the restraining spring 28 contacts the outer edge 61d of the back plate 61 and the outer edge 81d of the back plate 81.

[0084] As shown in Figure 5, the restraining spring 28 pushes the first brake pad 23 toward the central axis Ax, causing the first flat surface 76a of the concave surface 76 to be pressed against the outer circumferential surface 25a of the pad pin 25. In other words, the restraining spring 28 holds the first brake pad 23 between the restraining spring 28 and the pad pin 25. Furthermore, the first brake pad 23 is also pressed against the pad pin 27.

[0085] The restraining spring 28 pushes the second brake pad 24 toward the central axis Ax, causing the concave surface 96 to press against the pad pin 26. Furthermore, the second brake pad 24 is also pressed against the pad pin 27.

[0086] As shown in Figure 5, when not braking, the second plane 76b of the concave surface 76 is spaced apart from the pad pin 25. The restraining spring 28 pushes the pad pin 25 toward the central axis Ax via the first brake pad 23. Therefore, when not braking, the pad pin 25 is pressed against the periphery of the end Pi of the inner surfaces 41a and 45a in the radial direction. The pad pin 25 is spaced apart from the concave surface 52 of the bridge 33. Note that the pad pin 25 may be spaced apart from the end Pi of the inner surfaces 41a and 45a in the radial direction, or it may be in contact with the concave surface 52.

[0087] For example, during braking, a pressure source such as a master cylinder or electric cylinder increases the pressure in the cylinders 38 of the inner housing 31 and outer housing 32. As a result, the first brake pad 23 is pushed by the two pistons 22. Furthermore, the second brake pad 24 is pushed by the single piston 22.

[0088] Pushed by the piston 22, the first brake pad 23 and the second brake pad 24 move axially toward the disc rotor 11 along the pad pins 25, 26, and 27. As a result, the friction material 62 of the first brake pad 23 and the friction material 82 of the second brake pad 24 are pressed against the disc rotor 11.

[0089] Figure 6 is a cross-sectional view showing a part of the brake caliper 12 during braking in this embodiment. When the friction material 62 comes into contact with the disc rotor 11 which is rotating in the forward direction Dcn, the first brake pad 23 receives a force in the forward direction Dcn from the disc rotor 11 due to the friction between the disc rotor 11 and the friction material 62.

[0090] The first brake pad 23 moves in the inclination direction Di in Figure 6 such that the second plane 76b of the concave surface 76 approaches the pad pin 25 along the first plane 76a. That is, the inclination direction Di is the direction along the first plane 76a.

[0091] The inclination direction Di is close to the forward rotation direction Dcn, but is different from the forward rotation direction Dcn. In this embodiment, the inclination direction Di is an oblique direction between the forward rotation direction Dcn and the radially outward direction (upper left in Figure 6).

[0092] As the first brake pad 23 moves in the inclined direction Di, the second plane 76b of the concave surface 76 comes into contact with the outer circumferential surface 25a of the pad pin 25. The pad pin 25 may also roll on the first plane 76a. By rotating the pad pin 25, wear on the pad pin 25 can be suppressed.

[0093] Furthermore, since the pad pin 25 is in contact with the concave surface 76, it receives a force in the forward rotation direction Dcn from the first brake pad 23. As a result, the pad pin 25 moves from the end Pi of the inner surfaces 41a and 45a on the radially inward side to the end Pr of the inner surfaces 41a and 45a and the curved surface 52a in the forward rotation direction Dcn, along the inner surfaces 41a and 45a and the curved surface 52a.

[0094] The pad pin 25 is supported circumferentially by the inner surfaces 41a and 45a and the end Pr of the curved surface 52a in the forward rotation direction Dcn. The inner surface 41a of the inner housing 31 and the inner surface 45a of the outer housing 32 support the pair of first brake pads 23 circumferentially via the pad pin 25, thereby restricting the movement of the pair of first brake pads 23 in the forward rotation direction Dcn.

[0095] Furthermore, the curved surface 52a of the bridge 33 supports a pair of first brake pads 23 between the inner housing 31 and the outer housing 32 via pad pins 25. The pad pins 25 make line or surface contact with the curved surface 52a. As a result, the curved surface 52a of the bridge 33 restricts the movement of the pair of first brake pads 23 in the forward rotation direction Dcn.

[0096] When the bridge 33 supports the first brake pad 23 via the pad pin 25, the concave surface 52 of the bridge 33 and the concave surface 76 of the first brake pad 23 contact the outer circumferential surface 25a of the pad pin 25. The concave surface 52, the pad pin 25, and the concave surface 76 are aligned in the circumferential direction.

[0097] When the concave surface 52 of the bridge 33 supports the first brake pad 23 via the pad pin 25, the fulcrum and the point of force application of the pad pin 25 are located in substantially the same position in the axial direction, or are close to each other. As a result, little or no bending stress is generated in the pad pin 25, or the bending stress in the pad pin 25 is reduced.

[0098] When the second plane 76b of the concave surface 76 collides with the pad pin 25, the force acting on the pad pin 25 from the first brake pad 23 moves the pad pin 25 in the forward rotation direction Dcn, as described above. Therefore, the collision sound (clinking sound) when the second plane 76b collides with the pad pin 25 is smaller compared to when the pad pin 25 is fixed.

[0099] Even before the second plane 76b collides with the pad pin 25, the pad pin 25 begins to move in the forward rotation direction Dcn due to friction between the first plane 76a and the pad pin 25. Therefore, the relative speed between the first brake pad 23 and the pad pin 25 when the second plane 76b collides with the pad pin 25 is smaller compared to when the pad pin 25 is fixed. Consequently, the cronk noise when the second plane 76b collides with the pad pin 25 is reduced.

[0100] Furthermore, the pad pin 25 moves along the cylindrical inner surfaces 41a, 45a and the curved surface 52a, from the radially inner end Pi to the forward rotation end Dcn. As a result, the pad pin 25 slides on the inner surfaces 41a, 45a and the curved surface 52a, but does not collide with them. Therefore, the pad pin 25 can suppress the generation of a cronk noise caused by collision with the inner surfaces 41a, 45a and the curved surface 52a.

[0101] When the friction material 82 of the second brake pad 24 comes into contact with the disc rotor 11 which is rotating in the forward direction Dcn, the friction between the disc rotor 11 and the friction material 82 causes the second brake pad 24 to receive a force in the forward direction Dcn from the disc rotor 11. The caliper body 21 supports the pair of second brake pads 24 in the circumferential direction via pad pins 27, thereby restricting the movement of the pair of second brake pads 24 in the forward direction Dcn.

[0102] The caliper body 21 receives the braking force (braking torque) transmitted via the first brake pad 23 and pad pin 25 and transmits it to the vehicle body 1. The caliper body 21 also receives the braking torque transmitted via the second brake pad 24 and pad pin 27 and transmits it to the vehicle body 1. As a result, the disc brake device 10 brakes the disc rotor 11.

[0103] On the other hand, when the friction material 82 comes into contact with the disc rotor 11 which is rotating in the reverse direction Dcr, the friction between the disc rotor 11 and the friction material 82 causes the second brake pad 24 to receive a force in the reverse direction Dcr from the disc rotor 11.

[0104] The pad pin 26 receives a force in the reverse direction Dcr from the second brake pad 24. As a result, the pad pin 26 moves in the reverse direction Dcr within the holes 42, 46. The curved surface 52a of the bridge 34 supports the pair of second brake pads 24 via the pad pin 26 between the inner housing 31 and the outer housing 32. As a result, the curved surface 52a of the bridge 34 restricts the movement of the pair of second brake pads 24 in the reverse direction Dcr.

[0105] When the concave surface 52 of the bridge 34 supports the second brake pad 24 via the pad pin 26, the fulcrum and the point of force application of the pad pin 26 are located in substantially the same position in the axial direction, or are close to each other. As a result, there is little or no bending stress on the pad pin 26, or the bending stress on the pad pin 26 is reduced.

[0106] Furthermore, when the concave surface 96 collides with the pad pin 26, the pad pin 26 moves in the reverse direction Dcr inside the holes 42 and 46. As a result, the cronk noise is reduced compared to when the pad pin 25 is fixed.

[0107] When the friction material 62 of the first brake pad 23 comes into contact with the disc rotor 11 which is rotating in the reverse direction Dcr, the friction between the disc rotor 11 and the friction material 62 causes the first brake pad 23 to receive a force in the reverse direction Dcr from the disc rotor 11. The caliper body 21 restricts the movement of the pair of first brake pads 23 in the reverse direction Dcr by supporting the pair of first brake pads 23 in the circumferential direction via pad pins 27.

[0108] The caliper body 21 receives braking torque transmitted via the first brake pad 23 and pad pin 27 and transmits it to the vehicle body 1. The caliper body 21 also receives braking torque transmitted via the second brake pad 24 and pad pin 26 and transmits it to the vehicle body 1. As a result, the disc brake device 10 brakes the disc rotor 11.

[0109] In this embodiment, the first brake pad 23 is supported by pad pins 25 and 27. The second brake pad 24 is supported by pad pins 26 and 27. On the other hand, the first brake pad 23 and the second brake pad 24 are spaced apart from the caliper body 21 at least in the radial and circumferential directions, both during braking and non-braking. That is, during braking, the caliper body 21 receives braking torque from the first brake pad 23 and the second brake pad 24 not directly, but via the pad pins 25, 26, and 27.

[0110] The holes 41, 42, 45, and 46, the notches 55 in the bridge 33, and the notches 55 in the bridge 34 are machined, for example, by an end mill. For example, the end mill cuts the inner housing 31 and the bridge 33 to form the holes 41 and a portion of the notches 55 in the bridge 33. The end mill also cuts the outer housing 32 and the bridge 33 to form the holes 45 and another portion of the notches 55 in the bridge 33.

[0111] A recess 56 is provided between a portion of the notch 55 formed together with the hole 41 and another portion of the notch 55 formed together with the hole 45. The recess 56 can prevent the formation of a step between the portion of the notch 55 formed together with the hole 41 and the other portion of the notch 55 formed together with the hole 45 due to misalignment of the end mill.

[0112] As the pressure in cylinder 38 decreases, the first brake pad 23 and the second brake pad 24 move axially away from the disc rotor 11. This releases the brakes. The restraining spring 28 pushes the first brake pad 23 toward the central axis Ax, causing the second plane 76b of the concave surface 76 to move away from the pad pin 25. Furthermore, the pad pin 25 moves from the ends Pr of the inner surfaces 41a, 45a and the curved surface 52a in the forward rotation direction Dcn to the ends Pi of the inner surfaces 41a, 45a in the radial direction.

[0113] In the disc brake device 10 according to the embodiment described above, the pad pin 25 has a width smaller than the hole 41 around the central axis Ax, is fitted into the hole 41 so as to be movable around the central axis Ax, and extends axially between the inner housing 31 and the outer housing 32. The caliper body 21 is configured to support the first brake pad 23 via the pad pin 25, thereby restricting the movement of the first brake pad 23 in the forward rotation direction Dcn around the central axis Ax.

[0114] When the first brake pad 23 contacts the disc rotor 11 rotating in the forward direction Dcn, friction acts on the first brake pad 23 with a force in the forward direction Dcn. As a result, the first brake pad 23 pushes the pad pin 25 in the forward direction Dcn, causing the pad pin 25 to move in the forward direction Dcn within the hole 41. For example, when the pad pin 25 reaches the end Pr of the hole 41 in the forward direction Dcn, the caliper body 21 supports the pad pin 25, restricting the movement of the pad pin 25 and the first brake pad 23 in the forward direction Dcn. That is, the pad pin 25 moves within the hole 41 from the time the first brake pad 23 contacts the disc rotor 11 until it is supported by the caliper body 21. This allows the pad pin 25 to mitigate the impact when it contacts the first brake pad 23 compared to when it is fixed to the caliper body 21, and consequently reduce the impact noise (clinking noise).

[0115] The first brake pad 23 has a concave surface 76 supported by a pad pin 25 so that the first brake pad 23 can move axially. The concave surface 76 has a first plane 76a and a second plane 76b. The first plane 76a restricts the first brake pad 23 from moving closer to the central axis Ax by contacting the pad pin 25. The second plane 76b restricts the first brake pad 23 from moving away from the central axis Ax by contacting the pad pin 25. The first plane 76a and the second plane 76b extend in a tapering manner in the reverse direction Dcr, opposite to the forward direction Dcn.

[0116] For example, when the first plane 76a contacts the pad pin 25, the concave surface 76 is supported by the pad pin 25. When a force in the forward rotation direction Dcn acts on the first brake pad 23, it moves approximately in the forward rotation direction Dcn so that the pad pin 25 approaches the second plane 76b along the first plane 76a. Before contacting the second plane 76b, the pad pin 25 begins to move in the forward rotation direction Dcn due to friction between the pad pin 25 and the first plane 76a. That is, before the second plane 76b collides with the pad pin 25, both the first brake pad 23 and the pad pin 25 move in the forward rotation direction Dn, and the relative speed between the first brake pad 23 and the pad pin 25 is reduced. In addition, the first brake pad 23 moves in an inclined direction Di relative to the pad pin 25, which is in a direction along the first plane 76a, close to the forward rotation direction Dcn, and different from the forward rotation direction Dcn. In other words, the concave surface 76 can distribute the force acting on the first brake pad 23 in the forward rotation direction Dcn to the inclination direction Di and to the direction in which the second plane 76b contacts the pad pin 25. As a result, the brake caliper 12 can mitigate the impact when the pad pin 25 contacts the second plane 76b of the first brake pad 23, and consequently reduce the cronk noise.

[0117] The hole 41 is circular. The pad pin 25, pressed by the first brake pad 23, moves along the inner surface 41a of the circular hole 41 to the end Pr of the inner surface 41a in the forward rotation direction Dcn. Therefore, although the pad pin 25 slides along the inner surface 41a of the hole 41, it does not collide with the inner surface 41a of the hole 41, and can reach the end Pr of the inner surface 41a in the forward rotation direction Dcn. Consequently, the generation of a croaking noise caused by the pad pin 25 colliding with the caliper body 21 can be suppressed.

[0118] The pad pin 25 extends axially from at least one of the inner housing 31 and the outer housing 32 between the inner housing 31 and the outer housing 32. The bridge 33 is configured to support the first brake pad 23 via the pad pin 25 between the inner housing 31 and the outer housing 32, thereby restricting the movement of the first brake pad 23 in the forward rotation direction Dcn about the central axis Ax.

[0119] When the pad pin 25 is pushed in the forward rotation direction Dcn by the first brake pad 23, it eventually contacts not only the inner surface 41a of the hole 41 but also the bridge 33. The bridge 33 also supports the pad pin 25 during braking. The first brake pad 23 applies a bending moment in the forward rotation direction Dcn to the pad pin 25, which extends axially from the inner housing 31 and the outer housing 32. However, since the bridge 33 supports the pad pin 25 between the inner housing 31 and the outer housing 32, it is possible to prevent bending stress from occurring in the pad pin 25 or to reduce the bending stress on the pad pin 25. Therefore, the brake caliper 12 does not need to make the pad pin 25 thicker due to bending stress during braking, and the pad pin 25 can be made thinner.

[0120] The bridge 33 has a concave surface 52 recessed from one end 51 of the bridge 33 in the reverse direction Dcr, opposite to the forward direction Dcn. The first brake pad 23 has a concave surface 76 opposite to the concave surface 52. The concave surface 76 is supported by a pad pin 25 so that the first brake pad 23 is axially movable. When the bridge 33 supports the first brake pad 23 via the pad pin 25, the concave surface 52 and the concave surface 76 are in contact with the pad pin 25.

[0121] When the bridge 33 supports the first brake pad 23 via the pad pin 25, substantially the same portion of the pad pin 25 in the axial direction is pushed from opposite directions by the concave surface 52 and the concave surface 76. This allows the brake caliper 12 to suppress the generation of bending stress on the pad pin 25. If the concave surface 52 and the concave surface 76 support the pad pin 25 at positions spaced apart from each other in the axial direction, a bending moment will act on the pad pin 25. However, since the bridge 33 supports the pad pin 25 between the inner housing 31 and the outer housing 32, the distance between the position where the first brake pad 23 pushes the pad pin 25 (point of force application) and the position where the pad pin 25 is supported by the caliper body 21 (fulcrum) becomes shorter. Therefore, the brake caliper 12 can reduce the bending stress on the pad pin 25.

[0122] The pad pin 25 has a cylindrical outer surface 25a that extends in the axial direction. The concave surface 52 has a cylindrical or elliptical curved surface 52a that extends in the axial direction. When the bridge 33 supports the first brake pad 23 via the pad pin 25, the curved surface 52a and the concave surface 76 come into contact with the outer surface 25a.

[0123] The curved surface 52a of the concave surface 52 and the outer circumferential surface 25a of the pad pin 25 can be in line contact or surface contact. This allows the brake caliper 12 to increase the contact area between the concave surface 52 and the pad pin 25, thereby reducing the stress generated on the pad pin 25. Furthermore, the pad pin 25, which is pressed by the first brake pad 23, moves along the cylindrical curved surface 52a to the end Pr of the curved surface 52a in the forward rotation direction Dcn. Therefore, even though the pad pin 25 slides along the curved surface 52a, it does not collide with the curved surface 52a and can reach the end Pr of the curved surface 52a in the forward rotation direction Dcn. Consequently, the generation of a croaking noise caused by the pad pin 25 colliding with the caliper body 21 can be suppressed.

[0124] A hole 45 is provided in the outer housing 32. The pad pin 25 has a width smaller than the hole 45 around its central axis Ax and is fitted into the hole 45 so as to be movable around the central axis Ax. The pad pin 25 extends axially from the inner housing 31 and the outer housing 32.

[0125] The pad pin 25 is supported by the inner surface 41a of hole 41 and the inner surface 45a of hole 45, and supports the first brake pad 23 between hole 41 and hole 45. This prevents the pad pin 25 from tilting inside hole 41 and hole 45. Consequently, the pad pin 25 can move more reliably around the central axis Ax, thereby reducing cronk noise. Furthermore, the pad pin 25 can support the first brake pad 23 not as a cantilever beam, but as a double-supported beam (simply supported beam or fixed beam at both ends). This allows the brake caliper 12 to reduce the bending stress on the pad pin 25.

[0126] The pad pin 25 is spaced radially outward from the disc rotor 11, perpendicular to the central axis Ax. This prevents the pad pin 25 from interfering with the disc rotor 11. Furthermore, compared to the case where the pad pin 25 is located radially inside the edge of the disc rotor 11, the distance between the point where the first brake pad 23 and the pad pin 25 collide and the central axis Ax becomes longer. As a result, the force exerted by the first brake pad 23 on the pad pin 25 during braking is reduced. Consequently, the brake caliper 12 can reduce the bending stress on the pad pin 25.

[0127] In the embodiments described above, the pad pins 25, 26, and 27 extend from both the inner housing 31 and the outer housing 32. However, the pad pins 25, 26, and 27 may protrude from only one of the inner housing 31 and the outer housing 32. In this case, the pad pins 25, 26, and 27 may be spaced apart from the edge of the disc rotor 11 radially outward toward the central axis Ax.

[0128] The pad pin 25 may be spaced apart from the bridge 33 when it is supported by the ends Pr of the inner surfaces 41a and 45a of the holes 41 and 45. In this case as well, the relative speed of the first brake pad 23 and pad pin 25 with respect to the caliper body 21 decreases, thus reducing the cronk noise.

[0129] A brake caliper according to at least one embodiment described above includes, as an example, a caliper body having two side walls spaced apart from each other in the axial direction along the rotation axis of a disc rotor, and a connecting wall connecting the two side walls; a pin extending in the axial direction from at least one of the two side walls between the two side walls; and a brake pad located between the two side walls and supported by the pin so as to be movable in the axial direction, wherein the connecting wall is configured to restrict the movement of the brake pad in a first circumferential direction around the rotation axis by supporting the brake pad via the pin between the two side walls. Thus, as an example, when the brake pad contacts a disc rotor rotating in a first circumferential direction, a first circumferential force acts on the brake pad due to friction. The brake caliper brakes the disc rotor by supporting the brake pad via the pin through the connecting wall. That is, the connecting wall supports the pin during braking. The brake pad acts a first circumferential bending moment on the pin extending axially from the side wall. However, since the connecting wall supports the pin between the two side walls, it can prevent or reduce bending stress on the pin. Therefore, the brake caliper does not need to make the pin thicker due to bending stress during braking, and the pin can be made thinner.

[0130] In the brake caliper described above, for example, the connecting wall has a first concave surface recessed from one end of the connecting wall in a second circumferential direction opposite to the first circumferential direction, and the brake pad has a second concave surface facing the first concave surface, and is supported by the pin so that the brake pad is movable in the axial direction, and when the connecting wall supports the brake pad via the pin, the first concave surface and the second concave surface come into contact with the pin. Therefore, for example, when the connecting wall supports the brake pad via the pin, substantially the same portion of the pin in the axial direction is pushed in opposite directions by the first concave surface and the second concave surface. As a result, the brake caliper can suppress the generation of bending stress on the pin. Note that if the first concave surface and the second concave surface support the pin at positions spaced apart from each other in the axial direction, a bending moment will act on the pin. However, because the connecting wall supports the pin between the two side walls, the distance between the point where the brake pad pushes the pin and the point where the pin is supported by the caliper body becomes shorter. As a result, the brake caliper can reduce the bending stress on the pin.

[0131] In the brake caliper described above, for example, the pin has a cylindrical outer surface extending in the axial direction, and the first concave surface has a cylindrical or elliptical curved surface extending in the axial direction. When the connecting wall supports the brake pad via the pin, the curved surface and the second concave surface come into contact with the outer surface. Therefore, for example, the curved surface of the first concave surface and the outer surface of the pin can be in line contact or surface contact. This allows the brake caliper to increase the contact area between the first concave surface and the pin, and consequently reduce the stress generated in the pin.

[0132] In the brake caliper described above, for example, the pin extends axially from the two side walls. Therefore, for example, the pin can support the brake pad not as a cantilever but as a double-supported beam (simply supported beam or fixed-end beam). This allows the brake caliper to reduce the bending stress on the pin.

[0133] In the brake caliper described above, for example, the pin is spaced radially outward from the disc rotor, perpendicular to the axis of rotation. Therefore, for example, interference between the pin and the disc rotor can be suppressed. Furthermore, compared to the case where the pin is located radially inside the edge of the disc rotor, the distance between the contact point between the brake pad and the pin and the axis of rotation is increased. As a result, the force exerted on the pin by the brake pad during braking is reduced. Consequently, the brake caliper can reduce the bending stress on the pin.

[0134] 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.

Claims

1. A brake caliper comprising: a caliper body having two side walls spaced apart from each other in the axial direction along the rotation axis of a disc rotor, and a connecting wall connecting the two side walls; a pin extending in the axial direction from at least one of the two side walls between the two side walls; and a brake pad located between the two side walls and supported by the pin so as to be movable in the axial direction, wherein the connecting wall is configured to restrict the movement of the brake pad in a first circumferential direction around the rotation axis by supporting the brake pad via the pin between the two side walls.

2. The brake caliper according to claim 1, wherein the connecting wall has a first concave surface recessed from one end of the connecting wall in a second circumferential direction opposite to the first circumferential direction, the brake pad is supported by the pin so as to be movable in the axial direction and has a second concave surface facing the first concave surface, and when the connecting wall supports the brake pad via the pin, the first concave surface and the second concave surface contact the pin.

3. The brake caliper according to claim 2, wherein the pin has a cylindrical outer surface extending in the axial direction, the first concave surface has a cylindrical or elliptical curved surface extending in the axial direction, and when the connecting wall supports the brake pad via the pin, the curved surface and the second concave surface contact the outer surface.

4. The brake caliper according to claim 1, wherein the pin extends axially from the two side walls.

5. The brake caliper according to claim 1, wherein the pin is spaced radially outward from the disc rotor, perpendicular to the axis of rotation.

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