Disc brake device

Abstract

In this disk brake device (10), a pair of brake pads (48L, 48R) respectively comprise friction materials (58L, 58R) and rear plates (60L, 60R). At least a part of a retainer (72) is provided on a radially outer side of a brake disk (16) with respect to each of the friction materials (58L, 58R). In addition, at least a part of the retainer (72) is provided at substantially the same height as each of the rear plates (60L, 60R) and at substantially the same position in the circumferential direction (C) of the brake disk (16).

Description

[Technical field]

[0001] The present invention relates to a disc brake device. [Background technology]

[0002] Conventionally, in a disc brake device, a piston housed in a brake caliper is actuated to cause a pair of brake pads to clamp a brake disc. In this way, the pair of brake pads brake the brake disc. Each of the pair of brake pads includes a friction material and a back plate. Each of the friction materials contacts the brake disc. Each of the back plates is provided on the back surface of the friction material. In this case, the pair of brake pads are held in the brake caliper by abutting each of the back plates.

[0003] WO 2019 / 049539 discloses that the width of the retainer is such that it straddles each of the friction materials. WO 2019 / 049539 also discloses that the width of the end of the retainer is such that it straddles each of the backing plates. Summary of the Invention

[0004] If the width of the retainer is narrowed, the weight of the retainer becomes lighter. However, if the width of the retainer is narrowed, there is a possibility that a part may accidentally enter between a pair of brake pads (the gap between each friction material) during maintenance of a vehicle equipped with a disc brake device. As a result, there is a possibility that the time required for maintenance work will increase.

[0005] Therefore, an object of the present invention is to solve the above-mentioned problems.

[0006] A disc brake device according to one aspect of the present invention comprises a brake disc, a brake caliper arranged to straddle the brake disc, a piston housed in the brake caliper, a pair of brake pads housed in the brake caliper and pressing against the brake disc by operation of the piston, and a retainer provided on the brake caliper and abutting against the pair of brake pads to hold the pair of brake pads to the brake caliper, wherein each of the pair of brake pads comprises a friction material having a contact surface that contacts a side of the brake disc, and a back plate having one surface attached to a back surface opposite to the contact surface of the friction material and the other surface pressed against the piston, and at least a part of the retainer is provided radially outside of the brake disc with respect to each of the friction materials, at approximately the same height as each of the back plates, and at approximately the same position in the circumferential direction of the brake disc.

[0007] According to this configuration, at least a portion of the retainer and each back plate are provided at approximately the same height and in approximately the same position, which makes it difficult for foreign matter to enter between the pair of brake pads (the gaps between the friction materials).

[0008] One end of the retainer in the circumferential direction and one end of the backing plate in the circumferential direction may be provided radially outside the brake disc with respect to each friction material, at approximately the same height and at approximately the same position in the circumferential direction.

[0009] According to this configuration, one end of the retainer and one end of each back plate are located at approximately the same height and at approximately the same position in the circumferential direction of the brake disc relative to each friction material, radially outward of the brake pads, thereby preventing foreign matter from entering between the pair of brake pads.

[0010] A width of one end of the retainer straddling a center line of the brake caliper may be substantially the same as a width of each gap between the friction materials straddling the center line.

[0011] According to this configuration, the width of one end of the retainer and the width of the gaps between the friction materials are made approximately the same, which makes it possible to make the retainer as small and lightweight as possible while preventing foreign matter from entering the gaps between the friction materials.

[0012] The retainer has an abutment portion that is provided on the central side of the brake caliper in the circumferential direction relative to one end of the retainer and abuts against each of the back plates, and the width of the retainer across the center line of the brake caliper may be narrower from the abutment portion toward the one end of the retainer.

[0013] According to this configuration, the width of the retainer is narrowed from the contact portion toward one end of the retainer. This allows the retainer to be made smaller and lighter while reliably holding the pair of brake pads in the brake caliper. The width of the contact portion is also wider than the width of one end of the retainer. This reliably prevents foreign matter from entering the gaps between the friction materials.

[0014] The retainer may further have a connecting portion connecting the abutment portion and one end of the retainer, and a width of the connecting portion across the center line may be wider than a width of the gap between each of the friction materials across the center line.

[0015] According to this configuration, the width of the connecting portion is wider than the width of the gap between the friction materials, which can reliably prevent foreign matter from entering the gap.

[0016] The width of the connecting portion across the center line may be narrower than the distance between the back plates.

[0017] According to this configuration, the width of the connecting portion is narrower than the distance between the back plates, which makes it possible to avoid interference between the retainer and the back plates.

[0018] Each of the back plates is provided on the central side in the circumferential direction from one end of the back plate and has a protrusion that protrudes radially outward of the brake disc relative to the friction material, the abutment portion has a shape that curves toward each of the back plates and abuts against each of the protrusions, and the connecting portion may be flat.

[0019] According to this configuration, the abutment portions are curved toward each back plate and abut against the protrusions. This allows the pair of brake pads to be held against the brake caliper in the circumferential and radial directions of the brake disc even if there is some wobble between the pair of brake pads and the brake caliper. In addition, since the connecting portion is flat, it is possible to apply markings or the like to the surface of the connecting portion to prevent incorrect assembly.

[0020] The retainer may be tapered in a stepwise manner from the contact portion toward one end of the retainer.

[0021] According to this configuration, the retainer tapers in a stepwise manner from the contact portion toward one end of the retainer, which makes it easy to obtain the above-mentioned effects.

[0022] One end of the retainer may engage with a recess provided in the brake caliper.

[0023] According to this configuration, one end of the retainer engages with the recess. Therefore, it is not necessary to widen the width of one end of the retainer in order to fix it to the one end of the retainer. This makes it possible to narrow the one end of the retainer and prevent the retainer from becoming bulky. As a result, it is possible to further reduce the size and weight of the retainer.

[0024] If the entrance side of the brake caliper in the rotation direction of the brake disc is the disc rotation entrance side, and the exit side in the rotation direction is the disc rotation exit side, one end of the retainer and each of one ends of the back plates may be provided on either the disc rotation entrance side or the disc rotation exit side.

[0025] According to this configuration, one end of the retainer and one end of each of the back plates are provided on either the disk entrance side or the disk exit side, thereby easily achieving the above-mentioned effects.

[0026] When one of the disc entry side and the disc exit side is on the upper side of the disc brake device and the other is on the lower side of the disc brake device, one end of the retainer and each of one ends of the back plates may be provided on the lower side of the disc brake device.

[0027] According to this configuration, one end of the retainer and one end of each back plate are provided below the disc brake device, which makes it possible to efficiently prevent foreign matter that falls from above during maintenance or the like from entering the gaps between the friction materials provided below the disc brake device.

[0028] The retainer may extend circumferentially radially outward of the brake disc relative to each of the friction materials so as to cover gaps formed between the friction materials, and one end of each of the backing plates may protrude radially outward of the brake disc relative to the friction material.

[0029] According to this configuration, the retainer extends circumferentially to cover the gaps between the friction materials, and one end of each backing plate protrudes radially outward from the brake disc relative to the friction materials, thereby reliably preventing foreign matter from entering the gaps between the friction materials. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a right side view of a front wheel portion of a two-wheeled vehicle equipped with a disc brake device according to this embodiment. [Diagram 2] FIG. 2 is a rear view of the disc brake device. [Diagram 3] FIG. 3 is a partial perspective view of the disc brake device. [Figure 4] FIG. 4 is a partial rear view of the disc brake device. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] As shown in Fig. 1, the disc brake device 10 according to this embodiment is mounted on a vehicle as a wheel brake device. Fig. 1 illustrates, as an example, a case where the disc brake device 10 is applied to a brake device for a front wheel 14 of a two-wheeled vehicle 12. In addition, in the explanation of this embodiment, the forward direction of the two-wheeled vehicle 12 (to the right in Fig. 1) is defined as the forward direction, and the front-rear, left-right, and up-down directions will be explained. It should be noted that the disc brake device 10 is not limited to the example in Fig. 1. The disc brake device 10 is provided on the wheels (front wheel 14 or rear wheel) of various vehicles such as one-wheeled vehicles, three-wheeled vehicles, four-wheeled vehicles, etc.

[0032] In the following description, among the components of the disc brake device 10, the components on the left side may be described by adding the letter "L" following the reference number. Also, the components on the right side may be described by adding the letter "R" following the reference number. Furthermore, the components on the front side may be described by adding the letter "F" following the reference number. Furthermore, the components on the rear side may be described by adding the letter "B" following the reference number.

[0033] The disc brake device 10 includes a brake disc 16. The brake disc 16 is an annular plate-like member made of metal. The brake disc 16 is provided on the right side of the front wheel 14. The brake disc 16 is connected to the front wheel 14 so as to be substantially coaxial with an axle 22 of the front wheel 14. Therefore, the brake disc 16 rotates integrally with the front wheel 14. The disc brake device 10 further includes a brake caliper 20. The brake caliper 20 is attached to the front fork 18 on the right side of the front wheel 14. An axle support portion 24 is provided at the tip of the front fork 18. The axle support portion 24 supports the axle 22. A bracket 26 extending rearward on the right side of the front wheel 14 is connected to the axle support portion 24. As shown in FIGS. 1 to 7, the brake caliper 20 is supported by the bracket 26 so as to straddle the brake disc 16.

[0034] In Fig. 1, Fig. 2 and Fig. 5, the double-headed arrows C indicate the circumferential direction of the front wheel 14 and the brake disc 16. The arrows Cr indicate the rotational direction of the front wheel 14 and the brake disc 16. One end of the brake caliper 20 (one end in the rotational direction Cr) is the disc rotation-in side 28. The other end of the brake caliper 20 (the other end in the rotational direction Cr) is the disc rotation-out side 30. The disc rotation-in side 28 is the side (entrance side) where the brake disc 16 enters the brake caliper 20 when the two-wheeled vehicle 12 moves forward. In other words, when the front wheel 14 rotates while the two-wheeled vehicle 12 moves forward, the brake disc 16 enters the disc rotation-in side 28. The disc rotation-out side 30 is the side (exit side) where the brake disc 16 exits the brake caliper 20 when the two-wheeled vehicle 12 moves forward. That is, when the front wheel 14 rotates while the two-wheeled vehicle 12 is moving forward, the brake disc 16 moves out from the disc rotation exit side 30 .

[0035] The brake caliper 20 is supported by a bracket 26 on the right rear side of the front wheel 14. The brake caliper 20 extends in a substantially vertical direction along the brake disc 16. Since the brake caliper 20 is located behind the front wheel 14, the lower side of the brake caliper 20 is the disc rotation in side 28. Also, the upper side of the brake caliper 20 is the disc rotation out side 30. For example, when the brake caliper 20 is disposed on the right front side of the front wheel 14, the lower side of the brake caliper 20 is the disc rotation out side 30. Also, in this case, the upper side of the brake caliper 20 is the disc rotation in side 28. In the following explanation, a case where the brake caliper 20 is disposed as shown in FIG. 1, FIG. 2 and FIG. 5 will be explained.

[0036] As shown in Figs. 1 to 7, the brake caliper 20 has a pair of action parts 32L, 32R, one bridge part 34B, and the other bridge part 34F. As shown in Figs. 2, 6, and 7, the brake disc 16 is disposed on the center line CL of the brake caliper 20. The pair of action parts 32L, 32R are disposed on both the left and right sides of the brake disc 16. One bridge part 34B connects the pair of action parts 32L, 32R on the radial outside of the brake disc 16. One bridge part 34B connects the pair of action parts 32L, 32R on the disc rotation entry side 28. The other bridge part 34F connects the pair of action parts 32L, 32R on the radial outside of the brake disc 16. The other bridge part 34F connects the pair of action parts 32L, 32R on the disc rotation exit side 30.

[0037] The pair of action portions 32L, 32R extend in a substantially arc shape along the brake disc 16. Therefore, the brake disc 16 fits into a gap 35 between the pair of action portions 32L, 32R. The brake disc 16 rotates in a rotation direction Cr at a middle position in the left-right direction of the gap 35. The left-right direction of the gap 35 is also the axial direction of the brake disc 16, the axial direction of the front wheel 14, and the vehicle width direction of the two-wheeled vehicle 12. The middle position is located on the center line CL of the brake caliper 20.

[0038] The right action part 32R has insertion holes 36B, 36F formed on the disk rotation entrance side 28 and the disk rotation exit side 30. The right action part 32R is fixed to the bracket 26 by two mounting bolts (not shown) that pass through the insertion holes 36B, 36F.

[0039] Each bridge portion 34B, 34F protrudes from the pair of acting portions 32L, 32R radially outward of the brake disc 16. Also, each bridge portion 34B, 34F connects the pair of acting portions 32L, 32R. Therefore, as shown in Figures 2, 4, and 5 to 7, an opening 40 that opens rearward is formed by the pair of acting portions 32L, 32R and the two bridge portions 34B, 34F.

[0040] As shown in Figures 2, 3 and 5, the pair of action parts 32L, 32R are formed with protrusions 42L, 42R that bulge rearward. The two protrusions 42L, 42R are formed in the center (the center in the circumferential direction C) of the pair of action parts 32L, 32R. In other words, the two protrusions 42L, 42R are formed in the middle of the two bridge parts 34B, 34F. A hanger pin 44 extending in the left-right direction penetrates the two protrusions 42L, 42R.

[0041] As shown in Figs. 2 to 7, the disc brake device 10 further includes a plurality of pistons 46L, 46R and a pair of brake pads 48L, 48R. The plurality of pistons 46L, 46R and the pair of brake pads 48L, 48R are housed in the brake caliper 20. That is, the gap 35 between the pair of action portions 32L, 32R forms a brake pad accommodating chamber 50. The pair of brake pads 48L, 48R are housed in the brake pad accommodating chamber 50. In addition, the plurality of pistons 46L, 46R are housed in the pair of action portions 32L, 32R.

[0042] Specifically, two cylinder holes 52L are formed in the left action portion 32L. The two cylinder holes 52L extend in the left-right direction. The two cylinder holes 52L open toward the brake disc 16. One cylinder hole 52L is formed between the protruding portion 42L and one bridge portion 34B. The other cylinder hole 52L is formed between the protruding portion 42L and the other bridge portion 34F. That is, the two cylinder holes 52L are formed on the front side and the rear side (upper side and lower side) of the left action portion 32L, respectively. Each cylinder hole 52L accommodates a piston 46L. A hydraulic chamber 54L is formed between each cylinder hole 52L and each piston 46L.

[0043] Similarly, two cylinder holes 52R are formed in the right action portion 32R. The two cylinder holes 52R extend in the left-right direction. The two cylinder holes 52R open toward the brake disc 16. One cylinder hole 52R is formed between the protruding portion 42R and one bridge portion 34B. The other cylinder hole 52R is formed between the protruding portion 42R and the other bridge portion 34F. That is, the two cylinder holes 52R are formed on the front side and the rear side (upper side and lower side) of the right action portion 32R, respectively. Each of the two cylinder holes 52R is formed to face the two cylinder holes 52L of the left action portion 32L. A piston 46R is accommodated in each cylinder hole 52R. A hydraulic chamber 54R is formed between each cylinder hole 52R and each piston 46R.

[0044] Thus, the brake caliper 20 is an opposed piston type four-pot caliper. The pair of brake pads 48L, 48R brake the brake disc 16 due to the operation of the pistons 46L, 46R. Therefore, the number of the pistons 46L, 46R accommodated in the brake caliper 20 may be any number. In addition, piston seals 53L, 53R are arranged on the inner wall portions of the left and right action parts 32L, 32R, respectively. The piston seals 53L, 53R slide against the pistons 46L, 46R, respectively, to keep the hydraulic chambers 54L, 54R liquid-tight with the brake fluid. In addition, dust seals 55L, 55R are arranged on the inner wall portions of the left and right action parts 32L, 32R, respectively. The dust seals 55L, 55R are arranged close to the brake pad accommodation chamber 50 relative to the piston seals 53L, 53R. The dust seals 55L, 55R are in sliding contact with the pistons 46L, 46R, thereby preventing dust such as wear powder generated by the brake pads 48L, 48R from entering the cylinder bores 52L, 52R.

[0045] The brake pad accommodating chamber 50 is formed by the inner surfaces of the pair of acting portions 32L, 32R facing the brake disc 16, the mutually facing inner surfaces of the two bridge portions 34B, 34F, and a bottom portion 56 of the brake caliper 20 on the radially inner side of the brake disc 16. The mutually facing inner surfaces of the two bridge portions 34B, 34F are side surfaces that are perpendicular to the circumferential direction C and extend in the left-right direction. The bottom portion 56 of the brake caliper 20 is a portion that extends from the bottom portions of the pair of acting portions 32L, 32R (portions of the pair of acting portions 32L, 32R located radially inner of the brake disc 16) toward the brake disc 16.

[0046] Each of the pair of brake pads 48L, 48R includes a friction material 58L, 58R and a back plate 60L, 60R. Each of the friction materials 58L, 58R has a contact surface (a side surface facing the brake disc 16) that contacts the side surface of the brake disc 16. Each of the friction materials 58L, 58R extends in an arc shape along the circumferential direction C. The contact surface of each of the friction materials 58L, 58R slides against the brake disc 16. Each of the back plates 60L, 60R is attached to the back surface (a side surface away from the brake disc 16) opposite to the contact surface of the friction materials 58L, 58R. Each of the back plates 60L, 60R is a metal plate having a substantially arc shape. One surface of each of the back plates 60L, 60R is attached to the back surface of the friction material 58L, 58R. The other surface of each of the back plates 60L, 60R faces the pistons 46L, 46R.

[0047] The bottom surface (the radially inner surface) of each back plate 60L, 60R is in contact with the bottom 56 of the brake caliper 20. Also, the side surface of the disk rotation entrance side 28 of each back plate 60L, 60R can be in contact with the inner surface of one bridge portion 34B. Furthermore, the side surface of the disk rotation exit side 30 of each back plate 60L, 60R can be in contact with the inner surface of the other bridge portion 34F.

[0048] A plurality of protrusions 62L, 62R, 64L, 64R, 66L, 66R, 68L, 68R are formed on each back plate 60L, 60R (see Figs. 3 and 5). The plurality of protrusions 62L, 62R, 64L, 64R, 66L, 66R, 68L, 68R are formed on the back surface (radial outer surface) of each back plate 60L, 60R. The plurality of protrusions 62L, 62R, 64L, 64R, 66L, 66R, 68L, 68R protrude rearward of the brake disc 16 (radial outer side of the brake disc 16). In addition, the plurality of protrusions 62L, 62R, 64L, 64R, 66L, 66R, 68L, 68R protrude rearward of each friction material 58L, 58R (radial outer side of the brake disc 16). Protrusions 70L, 70R are formed in the center (in the circumferential direction C) of the back surface of each back plate 60L, 60R, as shown in Figures 2, 3 and 5 to 7. Each protrusion 70L, 70R corresponds to the protrusions 42L, 42R of each action portion 32L, 32R. A hanger pin 44 passes through each of the protrusions 70L, 70R.

[0049] Specifically, each of the protrusions 62L, 62R is located at an end of the disc entrance side 28 of each of the back plates 60L, 60R. Each of the protrusions 62L, 62R protrudes from the back surface of each of the back plates 60L, 60R radially outward of the brake disc 16. Each of the protrusions 62L, 62R is capable of contacting the inner surface of one of the bridge portions 34B.

[0050] Further, each of the protrusions 64L, 64R is located at the end of the disc rotation side 30 of each of the back plates 60L, 60R. Each of the protrusions 64L, 64R protrudes from the back surface of each of the back plates 60L, 60R radially outward of the brake disc 16. Each of the protrusions 64L, 64R is capable of contacting the inner surface of the other bridge portion 34F.

[0051] Furthermore, each of the protrusions 66L, 66R is located on the disk rotation side 28 (upstream side in the circumferential direction C and the rotation direction Cr) with respect to the central protrusions 70L, 70R of each of the back plates 60L, 60R. Each of the protrusions 66L, 66R protrudes from the back surface of each of the back plates 60L, 60R toward the radial outside of the brake disc 16. The protrusion amount of each of the protrusions 66L, 66R toward the radial outside of the brake disc 16 is smaller than the protrusion amount of each of the protrusions 70L, 70R toward the radial outside of the brake disc 16. In addition, the tip surface (the back surface on the radial outside) of each of the protrusions 66L, 66R is inclined toward the tip of the protrusion 70L, 70R.

[0052] Furthermore, each of the protrusions 68L, 68R is located on the disc rotation side 30 (downstream side in the circumferential direction C and the rotation direction Cr) with respect to the protrusions 70L, 70R of each of the back plates 60L, 60R. Each of the protrusions 68L, 68R protrudes from the back surface of each of the back plates 60L, 60R toward the radial outside of the brake disc 16. The protrusion amount of each of the protrusions 68L, 68R toward the radial outside of the brake disc 16 is smaller than the protrusion amount of each of the protrusions 70L, 70R toward the radial outside of the brake disc 16. In addition, the tip surface (the back surface on the radial outside) of each of the protrusions 68L, 68R is inclined toward the tip of the protrusion 70L, 70R.

[0053] In this manner, the pair of brake pads 48L, 48R are positioned in the circumferential direction C by the back plates 60L, 60R (projections 62L, 62R, 64L, 64R) coming into surface contact with the inner surfaces of the two bridge portions 34B, 34F. In addition, in the pair of brake pads 48L, 48R, the back plates 60L, 60R come into surface contact with the bottom portion 56 of the brake caliper 20. In addition, the back plates 60L, 60R are pivotally supported by the hanger pin 44. As a result, the pair of brake pads 48L, 48R are positioned in the radial direction of the brake disc 16. In this manner, the pair of brake pads 48L, 48R are accommodated in the brake pad accommodating chamber 50.

[0054] As shown in Figs. 1 to 7, the brake caliper 20 further includes a retainer 72. The retainer 72 elastically biases the pair of brake pads 48L, 48R. The pair of brake pads 48L, 48R are held at the bottom 56 of the brake caliper 20 by the biasing force from the retainer 72. The retainer 72 is a leaf spring member extending along the circumferential direction C. The retainer 72 covers the gaps 74 between the friction materials 58L, 58R on the radial outer side of the brake disc 16. Here, the width of the retainer 72 in the left-right direction (the width in the direction perpendicular to the center line CL) is Wr. In the following description, the left-right width of each part of the retainer 72 may be described by adding a lowercase alphabet letter following Wr.

[0055] The retainer 72 has an arc-shaped portion 72a. The arc-shaped portion 72a is engaged with the radially inner side of the center of the hanger pin 44. The following components are connected to the arc-shaped portion 72a on the disk rotation side 28 in order. The abutment portion 72b is connected to the arc-shaped portion 72a. The abutment portion 72b is located on the disk rotation side 28 with respect to the arc-shaped portion 72a. The abutment portion 72b is a wide (width Wra) portion that curves and abuts against the protrusions 66L, 66R of the back plates 60L, 60R. The connection portion 72c is connected to the abutment portion 72b. The connection portion 72c is located on the disk rotation side 28 with respect to the abutment portion 72b. The connection portion 72c is formed in a flat plate shape. The width Wrh of the connection portion 72c is approximately the same as the width of the arc-shaped portion 72a. The rotation side end 72d is connected to the connecting portion 72c. The rotation side end 72d is located on the disk rotation side 28 with respect to the connecting portion 72c. The width Wre of the rotation side end 72d is narrower than the width Wrh of the connecting portion 72c. A recess 76 is formed in the center (center in the left-right direction) of the inner surface of one of the bridge portions 34B. The rotation side end 72d is engaged with the recess 76.

[0056] The following components are connected in order to the arc-shaped portion 72a at the disc rotation exit side 30. The arc-shaped portion 72a is connected to a connecting portion 72e. The connecting portion 72e is located on the disc rotation exit side 30 relative to the arc-shaped portion 72a. The connecting portion 72e is formed in a flat plate shape. The width of the connecting portion 72e is approximately the same as the width of the arc-shaped portion 72a. The connecting portion 72e is connected to an abutting portion 72f. The abutting portion 72f is located on the disc rotation exit side 30 relative to the connecting portion 72e. The abutting portion 72f is a wide portion that abuts against the protrusions 64L, 64R of the back plates 60L, 60R in a curved state. The abutting portion 72f is the rotation exit side end of the retainer 72.

[0057] The abutment portion 72b of the retainer 72 abuts against the protrusions 66L, 66R of the back plates 60L, 60R. The abutment portion 72f of the retainer 72 abuts against the protrusions 64L, 64R of the back plates 60L, 60R. As a result, the pair of brake pads 48L, 48R are biased radially inward of the brake disc 16. The pair of brake pads 48L, 48R are also biased against the disc rotation side 30. As a result, even if there is some wobble between the pair of brake pads 48L, 48R and the brake caliper 20, the pair of brake pads 48L, 48R accommodated in the brake pad accommodating chamber 50 can be held by the brake caliper 20.

[0058] When the rider of the two-wheeled vehicle 12 operates a brake lever (not shown) while the front wheel 14 is rotating in the rotation direction Cr, the pistons 46L, 46R move axially inward (toward the brake disc 16). When the pistons 46L, 46R move axially inward, the back plates 60L, 60R constituting the pair of brake pads 48L, 48R are pressed. As a result, the friction materials 58L, 58R connected to the back plates 60L, 60R are pressed against the brake disc 16. As a result, the brake disc 16 and the front wheel 14 are braked by the pair of brake pads 48L, 48R.

[0059] In this case, the pair of brake pads 48L, 48R slide in the circumferential direction C (rotational direction Cr) due to the rotational force of the brake disc 16. As a result, the protrusions 64R, 64L of each back plate 60R, 60L abut against the inner surface of the bridge portion 34F. Therefore, the inner surface of the bridge portion 34F functions as a receiving surface for the torque acting on the pair of brake pads 48L, 48R.

[0060] In the disc brake device 10 according to this embodiment, the retainer 72 and the back plates 60L, 60R have the following characteristic configurations.

[0061] That is, as shown in Figs. 3, 5 and 7, at least a part of the retainer 72 and each back plate 60L, 60R are at approximately the same height on the radial outside of the brake disc 16. Also, at least a part of the retainer 72 and each back plate 60L, 60R are provided at approximately the same position in the circumferential direction C of the brake disc 16. Specifically, the rotation-in side end 72d (one end) of the retainer 72 is located on the radial outside of the brake disc 16 with respect to each of the friction materials 58L, 58R. That is, the rotation-in side end 72d protrudes radially outward of the brake disc 16 with respect to each of the friction materials 58L, 58R. Also, the protruding parts 62L, 62R (one end) of each back plate 60L, 60R are located on the radial outside of the brake disc 16 with respect to each of the friction materials 58L, 58R. That is, each of the protrusions 62L, 62R protrudes radially outward from each of the friction materials 58L, 58R of the brake disc 16. Furthermore, the rotation-in side end 72d (one end) of the retainer 72 and the protrusions 62L, 62R (one end) of each of the back plates 60L, 60R are located at approximately the same height in the up-down direction. Furthermore, the rotation-in side end 72d of the retainer 72 and the protrusions 62L, 62R of each of the back plates 60L, 60R are provided at approximately the same position in the circumferential direction C.

[0062] Also, as shown in FIGS. 2 to 4, FIGS. 6 and 7, the width Wr of the retainer 72 (the width Wr of the retainer 72 across the center line CL) becomes narrower from the contact portion 72b toward the entry-side end portion 72d. Specifically, as shown in FIG. 4, the retainer 72 gradually becomes narrower in the order of Wra (the width of the contact portion 72b), Wrh (the width of the connecting portion 72c), and Wre (the width of the entry-side end portion 72d) from the contact portion 72b toward the entry-side end portion 72d. Further, the width Wre of the entry-side end portion 72d is substantially the same as the width Wg (the width Wg of the gap 74 across the center line CL) in the left-right direction of the gap 74 between the friction materials 58L and 58R (Wre≈Wg).

[0063] In FIGS. 2 and 4, for the sake of illustrating the gap 74, a case where the width Wre of the entry-side end portion 72d is slightly narrower than the width Wg of the gap 74 is illustrated. In the present embodiment, the widths Wre and Wg of both may be the same width. Alternatively, the width Wre of the entry-side end portion 72d may be slightly wider than the width Wg of the gap 74. That is, the width Wre of the entry-side end portion 72d may be such that foreign matter does not enter the gap 74.

[0064] Also, as shown in FIGS. 2 to 4, FIGS. 6 and 7, the width Wrh of the connecting portion 72c is wider than the width Wg of the gap 74 between the friction materials 58L and 58R and narrower than the interval Wb between the back plates 60L and 60R (Wrh>Wg, Wrh<Wb). That is, there is a certain interval Wi between the back plates 60L and 60R and the connecting portion 72c.

[0065] Moreover, as shown in FIGS. 3 and 5, the contact portion 72b of the retainer 72 is curved toward the back plates 60L and 60R and contacts the protrusions 66L and 66R. Also, the connecting portion 72c is formed in a flat plate shape.

[0066] Further, the entry-side end portion 72d of the retainer 72 engages with a recess 76 formed in the central portion of the inner surface of one bridge portion 34B.

[0067] Summarizing the disc brake device 10 according to the present embodiment, it is as follows.

[0068] A disc brake comprising: a brake disc (16); a brake caliper (20) provided so as to straddle the brake disc (16); pistons (46L, 46R) accommodated in the brake caliper (20); a pair of brake pads (48L, 48R) that are accommodated in the brake caliper (20) and that press the brake disc (16) by operation of the pistons (46L, 46R); and a retainer (72) provided on the brake caliper (20) and that abuts against the pair of brake pads (48L, 48R) to hold the pair of brake pads (48L, 48R) in the brake caliper (20). A device (10), wherein each of the pair of brake pads (48L, 48R) comprises a friction material (58L, 58R) having a contact surface that contacts a side surface of the brake disc (16), and a back plate (60L, 60R) having one surface attached to the back surface opposite the contact surface of the friction material (58L, 58R) and the other surface pressed against the piston (46L, 46R), and at least a portion of the retainer (72) is provided radially outside of the brake disc (16) with respect to each friction material (58L, 58R), at approximately the same height as each back plate (60L, 60R), and at approximately the same position in the circumferential direction (C) of the brake disc (16).

[0069] According to this configuration, at least a portion of the retainer and each back plate are provided at approximately the same height and in approximately the same position, which makes it difficult for foreign matter to enter between the pair of brake pads (the gaps between the friction materials).

[0070] One end (72d) of the retainer (72) in the circumferential direction (C) and one end (62L, 62R) of the back plate (60L, 60R) in the circumferential direction (C) may be provided at approximately the same height and at approximately the same position in the circumferential direction (C) radially outside the brake disc (16) relative to each friction material (58L, 58R).

[0071] According to this configuration, one end of the retainer and one end of each back plate are provided at approximately the same height and at approximately the same position in the circumferential direction of the brake disc relative to each friction material, radially outwardly of the brake pads, thereby preventing foreign matter from entering between the pair of brake pads.

[0072] The width (Wre) of one end (72d) of the retainer (72) across the center line (CL) of the brake caliper (20) may be approximately the same as the width (Wg) of the gap (74) between each of the friction materials (58L, 58R) across the center line (CL).

[0073] According to this configuration, the width of one end of the retainer and the width of the gaps between the friction materials are made approximately the same, which makes it possible to make the retainer as small and lightweight as possible while preventing foreign matter from entering the gaps between the friction materials.

[0074] The retainer (72) has an abutment portion (72b) that is provided on the central side of the brake caliper (20) in the circumferential direction (C) relative to one end (72d) of the retainer (72) and abuts against each of the back plates (60L, 60R), and the width (Wr) of the retainer (72) across the center line (CL) of the brake caliper (20) may be narrowed from the abutment portion (72b) toward one end (72d) of the retainer (72).

[0075] According to this configuration, the width of the retainer is narrowed from the contact portion toward one end of the retainer. This allows the retainer to be made smaller and lighter while reliably holding the pair of brake pads in the brake caliper. The width of the contact portion is also wider than the width of one end of the retainer. This reliably prevents foreign matter from entering the gaps between the friction materials.

[0076] The retainer (72) further has a connecting portion (72c) connecting the abutment portion (72b) and one end (72d) of the retainer (72), and a width (Wrh) of the connecting portion (72c) straddling the center line (CL) may be wider than a width (Wg) of the gap (74) between each of the friction materials (58L, 58R) straddling the center line (CL).

[0077] According to this configuration, the width of the connecting portion is wider than the width of the gap between the friction materials, which can reliably prevent foreign matter from entering the gap.

[0078] The width (Wrh) of the connecting portion (72c) across the center line (CL) may be smaller than the distance (Wb) between the back plates (60L, 60R).

[0079] According to this configuration, the width of the connecting portion is narrower than the distance between the back plates, which makes it possible to avoid interference between the retainer and the back plates.

[0080] Each of the back plates (60L, 60R) is provided on the central side in the circumferential direction (C) with respect to one end (62L, 62R) of the back plate (60L, 60R) and has a protrusion (66L, 66R) that protrudes radially outward of the brake disc (16) with respect to the friction material (58L, 58R), the abutment portion (72b) has a shape that curves toward the respective back plates (60L, 60R) and abuts against the respective protrusions (66L, 66R), and the connecting portion (72c) may be flat.

[0081] According to this configuration, the abutment portions are curved toward each back plate and abut against the protrusions. This allows the pair of brake pads to be held against the brake caliper in the circumferential and radial directions of the brake disc even if there is some wobble between the pair of brake pads and the brake caliper. In addition, since the connecting portion is flat, it is possible to apply markings or the like to the surface of the connecting portion to prevent incorrect assembly.

[0082] The retainer (72) may be tapered stepwise from the contact portion (72b) to the one end portion (72d) of the retainer (72).

[0083] According to this configuration, the retainer tapers in a stepwise manner from the contact portion toward one end of the retainer, which makes it easy to obtain the above-mentioned effects.

[0084] One end (72d) of the retainer (72) may engage with a recess (76) provided in the brake caliper (20).

[0085] According to this configuration, one end of the retainer engages with the recess. Therefore, it is not necessary to widen the width of one end of the retainer in order to fix it to the one end of the retainer. This makes it possible to narrow the one end of the retainer and prevent the retainer from becoming bulky. As a result, it is possible to further reduce the size and weight of the retainer.

[0086] If the entrance side in the rotation direction (Cr) of the brake disc (16) of the brake caliper (20) is defined as the disc rotation entrance side (28) and the exit side in the rotation direction (Cr) is defined as the disc rotation exit side (30), one end (72d) of the retainer (72) and each of one ends (62L, 62R) of the back plates (60L, 60R) may be provided on either the disc rotation entrance side (28) or the disc rotation exit side (30).

[0087] According to this configuration, one end of the retainer and one end of each of the back plates are provided on either the disk entrance side or the disk exit side, whereby the above-mentioned effects can be easily obtained.

[0088] When one of the disc rotation side (28) and the disc rotation side (30) is on the upper side of the disc brake device (10) and the other is on the lower side of the disc brake device (10), one end (72d) of the retainer (72) and each of one ends (62L, 62R) of each back plate (60L, 60R) may be provided on the lower side of the disc brake device (10).

[0089] According to this configuration, one end of the retainer and one end of each back plate are provided below the disc brake device, which makes it possible to efficiently prevent foreign matter that falls from above during maintenance or the like from entering the gaps between the friction materials provided below the disc brake device.

[0090] The retainer (72) extends along the circumferential direction (C) so as to cover a gap (74) formed between the friction materials (58L, 58R) radially outside the brake disc (16) relative to the friction materials (58L, 58R), and each of the one ends (62L, 62R) of the back plates (60L, 60R) may protrude radially outside the brake disc (16) relative to the friction materials (58L, 58R).

[0091] According to this configuration, the retainer extends circumferentially to cover the gaps between the friction materials, and one end of each backing plate protrudes radially outward from the brake disc relative to the friction materials, thereby reliably preventing foreign matter from entering the gaps between the friction materials.

[0092] The present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

Claims

1. A disc brake device (10) comprising: a brake disc (16); a brake caliper (20) arranged to straddle the brake disc (16); pistons (46L, 46R) accommodated in the brake caliper (20); a pair of brake pads (48L, 48R) accommodated in the brake caliper (20) and pressing the brake disc (16) by operation of the pistons (46L, 46R); and a retainer (72) provided on the brake caliper (20) and abutting against the pair of brake pads (48L, 48R) to hold the pair of brake pads (48L, 48R) to the brake caliper (20), Each of the pair of brake pads (48L, 48R) includes a friction material (58L, 58R) having a contact surface that contacts a side surface of the brake disc (16), and a back plate (60L, 60R) having one surface attached to a back surface opposite to the contact surface of the friction material (58L, 58R) and the other surface pressed against the piston (46L, 46R), The brake caliper (20) includes a hanger pin (44) extending in the axial direction of the brake disc (16) at a middle portion in the circumferential direction (C) of the brake disc (16) and penetrating the brake pads (48L, 48R), the retainer (72) has an abutment portion (72b) that is engaged with the hanger pin (44), extends in the circumferential direction (C) of the brake disc (16), and abuts against the back plate (60L, 60R), and a circumferential end portion (72d) that is one end portion (72d) of the retainer (72) in the circumferential direction (C) and extends from the abutment portion (72b) to be engaged with the radially outer side of the brake disc (16) on the inner surface of the brake caliper (20), One end (62L, 62R) of the back plate (60L, 60R) in the circumferential direction (C) protrudes radially outward from the back plate (60L, 60R), The circumferential position of the circumferential end (72d) is substantially the same as the circumferential position of one end (62L, 62R) of the back plate (60L, 60R), A disc brake device (10) characterized in that the radial position of the circumferential end (72d) in the radial direction of the brake disc (16) is approximately the same as the radial position of one end (62L, 62R) of the back plate (60L, 60R).

2. The disc brake device (10) according to claim 1, a width (Wre) of the circumferential end (72d) straddling a center line (CL) of the brake caliper (20) is approximately the same as a width (Wg) of a gap (74) between each of the friction materials (58L, 58R) straddling the center line (CL).

3. The disc brake device (10) according to claim 1 or 2, The abutment portion (72b) is provided on a central portion side of the brake caliper (20) in the circumferential direction (C) with respect to the circumferential end portion (72d), and abuts against each of the back plates (60L, 60R); A disc brake device (10) characterized in that a width (Wr) of the retainer (72) across a center line (CL) of the brake caliper (20) narrows from the abutment portion (72b) toward the circumferential end portion (72d).

4. The disc brake device (10) according to claim 3, The retainer (72) further has a connecting portion (72c) that connects the abutment portion (72b) and the circumferential end portion (72d), The disc brake device (10) is characterized in that a width (Wrh) of the connecting portion (72c) straddling the center line (CL) is wider than a width (Wg) of a gap (74) between each of the friction materials (58L, 58R) straddling the center line (CL).

5. The disc brake device (10) according to claim 4, The disc brake device (10) is characterized in that a width (Wrh) of the connecting portion (72c) across the center line (CL) is narrower than a distance (Wb) between the back plates (60L, 60R).

6. A disc brake device (10) according to claim 4 or 5, Each of the back plates (60L, 60R) is provided on a central side in the circumferential direction (C) with respect to one end (62L, 62R) of the back plate (60L, 60R), and has a protrusion (66L, 66R) protruding radially outwardly of the brake disc (16) with respect to the friction material (58L, 58R), The abutment portion (72b) has a shape curved toward each of the back plates (60L, 60R) and abuts against each of the protrusions (66L, 66R), The disc brake device (10) is characterized in that the connecting portion (72c) is flat.

7. In the disc brake device (10) according to any one of claims 3 to 6, The retainer (72) is tapered in a stepwise manner from the contact portion (72b) toward the circumferential end portion (72d).

8. In the disc brake device (10) according to any one of claims 1 to 7, The disc brake device (10) is characterized in that the circumferential end (72d) engages with a recess (76) provided in the brake caliper (20).

9. In the disc brake device (10) according to any one of claims 1 to 8, When the inlet side in the rotation direction (Cr) of the brake disc (16) of the brake caliper (20) is defined as the disc rotation inlet side (28) and the outlet side in the rotation direction (Cr) is defined as the disc rotation outlet side (30), if one of the disc rotation inlet side (28) and the disc rotation outlet side (30) is on the upper side of the disc brake device (10) and the other is on the lower side of the disc brake device (10), the circumferential end (72d) and each of one ends (62L, 62R) of each back plate (60L, 60R) are provided on the lower side of the disc brake device (10).

10. In the disc brake device (10) according to any one of claims 1 to 9, the retainer (72) extends along the circumferential direction (C) so as to cover a gap (74) formed between each of the friction materials (58L, 58R) on the radially outer side of the brake disc (16) relative to each of the friction materials (58L, 58R); A disc brake device (10) characterized in that one end (62L, 62R) of each of the back plates (60L, 60R) protrudes radially outward of the brake disc (16) relative to the friction material (58L, 58R).

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