disc brake

Abstract

Disc brake, which features: a brake caliper (3) designed to extend over an outer circumferential side of a disc (1) which rotates together with a wheel; an inner block (11, 31) and an outer block (21) which are arranged to press down on the disk (1); a piston (9) with an opening end face (9A) configured to push the inner block (11); and a claw section (7) designed to press the outer block (21); at which the inner block (11) has a first surface which is in contact with the disk (1) when the inner block presses on the disk, and has a second surface (13A) opposite the first surface, the second surface (13A) has at least one first opening (16, 17), the outer block (21) has a third surface which is in contact with the disk (1) when the outer block (21) presses on the disk (1), and has a fourth surface (23A) opposite the third surface, the fourth surface (23A) has at least one second opening (26, 27), and the at least one first opening (16, 17) and the at least one second opening (26, 27) are arranged such that, when the inner block (11) protrudes in the axial direction of the disk (1) towards the outer block (21), a center of gravity (Ki) of the at least one first opening (16, 17) and a center of gravity (Ko) of the at least one second opening (26, 27) are shifted relative to each other, in which the inner block (11) has: a first brake pad (12) forming the first surface; and a first plate (13) which forms the second surface (13A), wherein the outer block (21) exhibits: a second brake pad (22) forming the third surface; and a second plate (23), which forms the fourth surface (23A), and which at least one first opening (16, 17) and at least one second opening (26, 27) each extend through the first plate (13) and the second plate (23), characterized by the fact that the first brake pad (12) has a projection (12A) which is received into the at least one first opening (16, 17), and the second brake pad (22) has a projection (22A) which is received into the at least one second opening (26, 27), wherein an end surface (12A1) of the projection (12A) of the first brake pad (12), which partially penetrates the first opening (16, 17), is set back from the second surface (13A) of the first plate (13), wherein during a brake actuation the opening end surface (9A) of the piston (9) touches the second surface (13A) of the inner block (11) except for the first opening (16, 17), and wherein the opening end surface (9A) of the piston (9) is opposite the end surface (12A1) of the projection (12A) of the first brake pad (12), but does not touch it.

Description

TECHNICAL FIELD

[0001] The present invention relates to disc brakes that apply braking force to vehicles. STATE OF THE ART

[0002] A disc brake provided in a vehicle, such as an automobile, is configured to include: a brake caliper formed to extend over the outer peripheral side of a disc that rotates together with a wheel, an inner pad (inner brake pad) that presses the disc from the inside (inside) with respect to the brake caliper, an outer pad (outer brake pad) that presses the disc from the outside (outside) with respect to the brake caliper, a piston that presses the inner pad, and a claw portion that presses the outer pad (Patent Literature 1).

[0003] In this regard, PTL1 describes a technique in which a shim plate is provided between the piston and the inner pad, and a cutout portion is provided in a region of the shim plate abutting against the piston, thereby adjusting the surface pressure to be applied from the piston to the inner pad. CITATION LISTPATENT LITERATURE

[0004] PTL 1: Japanese Patent Application Publication No. H10-122 277 A

[0005] DE 195 11 287 A1 discloses features falling under the preamble of claim 1. DE 10 2013 216 592 A1 and DE 24 35 650 A1 are further prior art. SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0006] According to PTL1, it is assumed that the center of gravity position of the contact surface area between the inner pad and the piston (i.e., the center of gravity position of the adjacent surface) can be adjusted by adjusting the shape of the cutout portion in the intermediate plate. However, this structure usually results in increased costs and reduced productivity (ease of production) because an intermediate plate provided with a cutout portion is required.

[0007] An object of the present invention is to provide a disc brake capable of reducing costs and improving productivity. SOLUTION TO THE PROBLEM

[0008] The invention is defined by claim 1.

[0009] The disc brake according to one embodiment of the present invention is capable of reducing costs and improving productivity. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a vertical sectional view showing a disc brake according to a first embodiment. Fig. 2 is a side view of an inner block, viewed from an outer side (left side of the Fig. 1), which is one side of the brake pad. Fig. 3 is a side view of the inner block, viewed from an inside (right side of the Fig. 1), which is one side of the plate. Fig. 4 is a sectional view of the inner block, viewed from the IV-IV direction in Fig. 2. Fig. 5 is a side view of an outer block, viewed from an inner side (right side of the Fig. 1), which is one side of the brake pad. Fig. 6 is a side view of the outer block, viewed from an outside (left side of the Fig. 1), which is one side of the plate. Fig. 7 is a sectional view of the outer block, viewed from the VII-VII direction in Fig. 5. Fig. 8 is a side view showing second openings in the outer block projecting toward the inner block. Fig. 9 is a side view showing first openings in the inner block projecting toward the outer block. Fig. 10 is a side view showing an inner block according to a comparative example. Fig. 11 is a side view showing an outer block according to the comparative example. Fig. 12 is a vertical sectional view showing a disc brake according to a second embodiment. Fig. 13 is a side view showing second openings in an outer block projecting from the inner block. Fig. 14 is a side view showing first openings in the inner block projecting toward the outer block. DESCRIPTION OF EMBODIMENTS

[0010] Disc brakes according to embodiments will be described in detail below with reference to the accompanying drawings.

[0011] Fig. 1 to 9 show a first embodiment. According to Fig. 1, a disk 1 is rotatable together with a wheel (not shown). A mounting member 2, known as a carrier, is fixed to a non-rotating part (not shown) of a vehicle, at a position in the vicinity of the disk 1. The mounting member 2 is formed to extend over the outer peripheral side of the disk 1 in an axial direction of the disk 1 (ie, in the right / left direction in Fig. 1, Fig. 4 and Fig. 7 or the forward / backward direction in Fig. 2, Fig. 3, Fig. 5, Fig. 6, Fig. 8 and Fig. 9, which in the present application is referred to as the “axial direction of the disc”).

[0012] The attachment member 2 has two arm portions (not shown), a support portion 2A and a reinforcement beam 2B. The arm portions are in a rotation direction of the disk 1 (ie, the front / back direction in Fig. 1, Fig. 4 and Fig. 7 or the right / left direction in Fig. 2, Fig. 3, Fig. 5, Fig. 6, Fig. 8 and Fig. 9, which in the present application is referred to as the "rotational direction of the disc," "tangential direction of the disc," or "circumferential direction of the disc"). The arm portions extend in the axial direction of the disc 1 beyond the outer peripheral side of the disc 1. The arm portions support a brake caliper 3 via displacement pins (not shown), so that the brake caliper 3 is displaceable in the axial direction of the disc.

[0013] The support section 2A is provided to support the front ends (right ends in Fig. 1) of the arm portions to each other in an integral manner and is fixed to the non-rotating part of the vehicle at a position located on the inside of the windshield 1. The reinforcement beam 2B connects the rear or distal ends of the arm portions to each other at a position located on the outside of the windshield 1. Thus, the arm portions of the attachment member 2 are integrally connected to each other by the support portion 2A on the inside of the windshield 1 and integrally connected to each other by the reinforcement beam 2B on the outside of the windshield 1.

[0014] The mounting member 2 is provided on the inner side thereof with two pad guides (not shown) that guide an inner pad 11, which is an inner brake pad, in the axial direction of the disk. The pad guides are each formed, for example, in the shape of a U-groove having a U-shaped cross section (usually U-shaped cross section) extending in the axial direction of the disk. The pad guides are spaced from each other so that they are respectively arranged on one side and the other side, facing each other across the inner pad 11 in the rotational direction of the disk. The pad guides each have nose portions 14 and 15 of the inner pad 11 fitted (inserted) therein, with, for example, pad springs (not shown) provided therebetween.

[0015] Also on the outer side, the attachment member 2 is provided with two pad guides (not shown) that guide an outer pad 21, which is an outer brake pad, in the axial direction of the disk. The pad guides are each formed, for example, in the shape of a U-groove having a U-shaped cross section (usually U-shaped cross section) extending in the axial direction of the disk, in the same manner as the inner side pad guides. The pad guides are spaced from each other so that they are respectively arranged on one side and the other side, facing each other across the outer pad 21 in the rotational direction of the disk. The pad guides each have nose portions 24 and 25 of the outer pad 21 fitted (inserted) therein, with, for example, pad springs (not shown) provided therebetween.

[0016] The brake caliper 3 is mounted on the mounting member 2 (via sliding pins) so that it can move (slide) in the axial direction of the disc. The brake caliper 3 is configured to extend over the outer peripheral side of the disc 1 in the axial direction of the disc. The brake caliper 3 is configured to have an inner base portion 4, a bridge portion 5, and an outer base portion 6.

[0017] The inner foot portion 4 is provided on the inner side, i.e., one side, in the axial direction of the disk. The bridge portion 5 as a bridge is provided to extend in the axial direction of the disk from the inner foot portion 4 across the outer peripheral side of the disk 1 between the arm portions of the attachment member 2 to the outside, i.e., the other side. The outer foot portion 6 extends radially (up / down direction in Fig. 1 to 9, which is referred to in the present application as “radial direction of the disc”) inwards (in Fig. 1 to 9 downwards) of the disc 1, from the outside, that is, the remote or rear end of the bridge section 5. The outer foot section 6 has at its rear end a fork-shaped claw section 7. The claw section 7 abuts directly (i.e., without an intermediate element, for example, an intermediate plate, provided between the claw section 7 and the plate 23) against a plate 23 of the outer block 21. When the brake is applied (during braking), the claw section 7 presses the outer block 21 towards the outside surface (surface of the left side in Fig. 1) of disc 1.

[0018] The inner base portion 4 of the brake caliper 3 is provided with, for example, a single cylinder 8, thereby forming a single-bore structure. A piston 9 is slidably fitted into the cylinder 8. The cylinder 8 is supplied with brake fluid pressure from the outside when the brake is applied. Further, the inner base portion 4 is integrally provided with two pin attachment portions (not shown) protruding in the rotational direction of the disc. The pin attachment portions support the entire brake caliper 3 via the displacement pins to be slidable relative to the arm portions of the attachment member 2.

[0019] The piston 9 is formed in the shape of a bottom-closed cylinder and slidably fitted in the inner base portion 4 of the cylinder 8. The piston 9 abuts directly (i.e., without an intermediate member such as an intermediate plate provided between the piston 9 and the plate 13) against a plate 13 of the inner block 11 at an open end surface 9A, which is a rear end thereof. When the brake is applied, the piston 9 presses the inner block 11 toward the inner side surface (right-side surface in Fig. 1) of disc 1.

[0020] That is, when the brake fluid pressure is supplied from the outside into the cylinder 8, the piston 9 is displaced by the supplied fluid pressure in the axial direction of the disc toward the disc 1, whereby the inner pad 11 is pressed against the surface of one side (inner side surface) of the disc 1. At the same time, the caliper 3 receives a pressing counterforce from the disc 1. Consequently, the entire caliper 3 is displaced to the inside relative to the arm portions of the attachment member 2, and the claw portion 7 presses the outer pad 21 against the surface of the other side (outer side surface) of the disc 1. In this way, a braking force can be applied to the disc 1 and thus to the wheel.

[0021] In the following, the inner block 11 and the outer block 21, which are brake blocks, are shown in addition to the Fig. 1 with reference to Fig. 2 to 9. Fig. 2 to 4 show the inner block 11, and Fig. 5 to 7 show the outer block 21. Furthermore, Fig. 8 through holes 26 and 27 in the outer block 21, projecting towards the inner block 11 in the axial direction of the disc. Fig. Figure 9 shows through holes 16 and 17 in the inner block 11, projecting from the outer block 21 in the axial direction of the disk. The inner block 11 and the outer block 21 have the same structure (e.g., the same basic material, the same shape, the same thickness, and the same width), except that the positions of the through holes 16 and 17 in the inner block 11 and the positions of the through holes 26 and 27 in the outer block 21 differ from each other.

[0022] The inner pad 11 and the outer pad 21 are arranged to face the axially opposite sides of the disc 1, respectively. The inner pad 11 and the outer pad 21 are attached to the attachment member 2 so as to be movable in the axial direction of the disc. The inner pad 11 is pressed against the disc 1 by the piston 9, and the outer pad 21 is pressed against the disc 1 by the claw portion 7. That is, the inner pad 11 presses the disc 1 from the inside (one side in the axial direction of the disc), which is the inside of the caliper 3, and the outer pad 21 presses the disc 1 from the outside (the other side in the axial direction of the disc), which is the outside of the caliper 3.

[0023] As in Fig. 2 to 4, the inner pad 11 is configured to include a brake pad 12 as a friction element that comes into frictional contact with the surface (the surface of one side in the axial direction) of the disk 1, and a plate (backing plate) 13 provided on a surface of the inner pad 11 in the axial direction of the disk opposite to the brake pad 12. In this case, the brake pad 12 is fixed (bonded) to the plate 13, which is a flat plate extending in the rotation direction of the disk.

[0024] The plate 13 is formed of, for example, a metal or a resin (a synthetic resin) and has nose portions 14 and 15 as protrusions provided on the edges of opposite sides of the disk, respectively, in the rotational direction of the disk. The nose portions 14 and 15 are spaced apart from each other in the rotational direction of the disk. The nose portions 14 and 15 are slidably inserted (fitted) into the pad guides of the attachment member 2, respectively, with pad springs interposed therebetween. The nose portions 14 and 15 are configured to receive the torque (braking torque) when the vehicle's brake is applied. That is, the nose portions 14 and 15 form torque transmission portions that transmit the torque that the brake pad 12 receives from the disk 1 to the corresponding pad guides of the attachment member 2.

[0025] Furthermore, the plate 13 is provided with two through holes 16 and 17 spaced apart from each other in the rotational direction of the disc. The through holes 16 and 17 are arranged symmetrically with respect to the center in the rotational direction of the disc of the inner pad 11 (plate 13) (i.e., line-symmetrical with respect to a line passing through the center and running parallel to the Y-axis). Furthermore, the through holes 16 and 17 are each formed as a circular hole extending through the plate 13 in the axial direction of the disc. The through holes 16 and 17 serve as openings for venting gas from the brake pad 12 when the brake pad 12 and the plate 13 are attached to each other, that is, when the brake pad 12 is contact-bonded to the plate 13 by pressing the former against the latter (the openings are hereinafter referred to as "gas vent holes").

[0026] When the brake pad 12 and the plate 13 are attached to each other, as shown in Fig. 4, the brake pad 12 partially engages (engages) the through holes 16 and 17 in the form of projections 12A and 12B. In this case, the surfaces 12A1 and 12B1 of the projections 12A and 12B of the brake pad 12 are located closer to the disc 1 than a side surface 13A of the plate 13. Thus, a level difference is created between the end surfaces 12A1 and 12B1 of the projections 12A and 12B of the brake pad 12 and the side surface 13A of the plate 13, respectively.

[0027] Consequently, the opening end surface 9A of the piston 9, which presses the inner block 11, does not come into contact with portions of the side surface 13A of the plate 13 of the inner block 11 on which the through holes 16 and 17 are formed, but comes into contact with portions of the side surface 13A that are different from the through holes 16 and 17. That is, the opening end surface 9A of the piston 9 is in contact with the plate 13 of the inner block 11 at portions that are in Fig. 3 are marked with dots. Thus, the inner block 11 has a pair (two) of through holes 16 and 17 as first holes provided in a surface (side surface 13A of the plate 13) on a side thereof that does not come into contact with the disk 1.

[0028] As in Fig. 5 to 7, the outer pad 21 is configured to include a brake pad 22 as a friction member that comes into frictional contact with one surface (the other side surface in the axial direction) of the disk 1, and a plate (backing plate) 23 provided on a surface of the outer pad 21 opposite to the brake pad 22 in the axial direction of the disk, in the same manner as the inner pad 11. In this case, the brake pad 22 is fixed (bonded) on the plate 23, which is a flat plate extending in the rotation direction of the disk.

[0029] In the same manner as the plate 13 of the inner block 11, the plate 23 of the outer block 21 is formed of, for example, a metal or a resin (synthetic resin), and has nose portions 24 and 25 as protrusions provided at the edges of opposite sides of the disk, respectively, in the rotation direction of the disk. The nose portions 24 and 25 are spaced apart from each other in the rotation direction of the disk. The nose portions 24 and 25 are slidably inserted (fitted) into the block guides of the attachment member 2, with block springs interposed therebetween. The nose portions 24 and 25 are configured to receive torque (braking torque) when the brake of the vehicle is applied.That is, the nose portions 24 and 25 form torque transmission portions that transmit a torque that the brake pad 22 receives from the disc 1 to the associated pad guides of the attachment element 2.

[0030] Furthermore, the plate 23 is provided with two through holes 26 and 27 spaced apart from each other in the rotational direction of the disc. The through holes 26 and 27 are arranged symmetrically with respect to the center in the rotational direction of the disc of the outer pad 21 (plate 23) (i.e., line-symmetrical with respect to a line passing through the center and running parallel to the Y-axis). Furthermore, the through holes 26 and 27 are each formed as a circular opening extending through the plate 23 in the axial direction of the disc. The through holes 26 and 27 serve as gas vent holes for venting gas from the brake pad 22 when the brake pad 22 and the plate 23 are attached to each other, that is, when the brake pad 22 is contact-bonded to the plate 23 by pressing the former against the latter.

[0031] When the brake pad 22 and the plate 23 are attached to each other, as shown in Fig. 7, the brake pad 22 engages (fits) into the through holes 26 and 27 in the form of projections 22A and 22B. In this case, the end surfaces 22A1 and 22B1 of the projections 22A and 22B of the brake pad are located closer to the disc 1 than a side surface 23A of the plate 23. Thus, a level difference is created between each of the end surfaces 22A1 and 22B1 of the projections 22A and 22B of the brake pad 22 and the side surface 23A of the plate 23.

[0032] Consequently, the claw portion 7 of the brake caliper 3, which presses on the outer pad 21, is not in contact with areas of the side surface 23A of the plate 23 of the outer pad 21 on which the through holes 26 and 27 are formed, but is in contact with areas of the side surface 23A that are different from the through holes 26 and 27. That is, the claw portion 7 is in contact with the plate 13 of the inner pad 11 at areas that are in Fig. 6 are marked with dots. Thus, the outer block 21 has a pair (two) of through holes 26 and 27 as second holes provided in a surface (side surface 23A of the plate 23) on a side thereof not in contact with the disk 1.

[0033] The embodiment is arranged so that, as in Fig. 8 and Fig. 9, the centers of gravity (gravity centers) Ki, Ki of the through-holes 16 and 17 as first holes and the centers of gravity (gravity centers) Ko, Ko of the through-holes 26 and 27 as second holes are respectively shifted relative to each other when the inner block 11 protrudes toward the outer block 21 in the axial direction. That is, the through-holes 16 and 17 and the through-holes 26 and 27 are provided so that the centers of gravity Ki and Ko are shifted relative to each other (do not coincide) when the inner block 11 protrudes toward the outer block 21 in the axial direction of the disk (or the outer block 21 protrudes toward the inner block 11) in a state where the inner block 11 and the outer block 21 are attached to the attachment member 2.

[0034] In Fig. 8, the inner block 11 (plate 13 thereof) is shown by a solid line, and the through holes 26 and 27 in the outer block 21 are shown by a two-dot chain line when the inner block 11 and the outer block 21 protrude in the axial direction of the disk. On the other hand, in Fig. 9, the outer block 21 (plate 23 thereof) is shown by a solid line, and the through holes 16 and 17 in the inner block 11 are shown by a two-dot chain line when the outer block 21 and the inner block 11 protrude in the axial direction of the disk.

[0035] According to the embodiment, the center of gravity position (gravity center position or center position) Li of the contact surface area (areas located in Fig. 3 are marked with dots) between the inner block 11 and the piston 9 (opening end surface 9A thereof) and the center of gravity position (gravity center position or center position) Lo of the contact surface area (areas which are in Fig. 6) between the outer pad 21 and the claw portion 7 can be adjusted as desired according to the amount of displacement between the centers of gravity Ki, Ki of the through holes 16 and 17 as first holes and the centers of gravity Ko, Ko of the through holes 26 and 27 as second holes. Thus, according to the embodiment, the center of gravity position Li of the contact surface area between the inner pad 11 and the piston 9 and the center of gravity position Lo of the contact surface area between the outer pad 21 and the claw portion 7 can be adjusted as desired without requiring the provision of an intermediate member, such as an intermediate plate, between the inner pad 11 and the piston 9 and another intermediate member between the outer pad 21 and the claw portion 7.

[0036] Here, a direction connecting the nose portions 14 and 15 provided on the opposite sides of the inner block 11 and a direction connecting the nose portions 24 and 25 provided on the opposite sides of the outer block 21 are each defined as the X-axis, and a direction perpendicular to the X-axis in a plane of the plate 13 of the inner block 11 and in a plane of the plate 23 of the outer block 21 is defined as the Y-axis. In other words, the axis of the rotation direction of the disk is defined as the X-axis, and the axis in the radial direction of the disk is defined as the Y-axis. In this case, according to the embodiment, the centers of gravity Ki, Ki of the through holes 16 and 17 as first holes are respectively shifted in the Y-axis direction relative to the centers of gravity Ko, Ko of the through holes 26 and 27 as second holes.

[0037] In particular, the centers of gravity Ko, Ko of the through holes 26 and 27 as second holes are arranged closer to the side of the bridge portion 5 of the brake caliper 3 in the direction of the Y-axis (ie, closer to the upper side in Fig. 8 and Fig. 9) as the centers of gravity Ki, Ki of the through holes 16 and 17 as the first holes. Thus, the center of gravity position Lo of the contact surface area between the outer pad 21 and the claw portion 7 and the center of gravity position Li of the contact surface area between the inner pad 11 and the piston 9 can be brought closer to each other in the Y-axis direction. Thus, the brake pad 22 of the outer pad 21 and the brake pad 12 of the inner pad 11 have the same wear tendency.

[0038] The operation of the disc brake according to the embodiment constructed as described above will be explained below.

[0039] When the vehicle's brake is applied, brake fluid pressure is first supplied to the cylinder 8 of the brake caliper 3, causing the piston 9 to displace toward the disc 1, pressing the inner pad 11 against the surface of one side of the disc 1. At the same time, the brake caliper 3 receives a counter-pressure force from the disc 1. Consequently, the entire brake caliper 3 is displaced toward the inside relative to the arm portions of the mounting member 2. Thus, the claw portion 7 of the brake caliper 3 presses the outer pad 21 against the surface of the other side of the disc 1.

[0040] The inner pad 11 and the outer pad 21 can thus hold the disc 1, which rotates together with the wheel, between them in the axial direction from both sides and apply braking forces to the disc 1. When the brake application is released, the supply of fluid pressure to the cylinder 8 is stopped. Thus, the inner pad 11 and the outer pad 21 separate from the disc 1 and return to their non-braking states.

[0041] During the braking function described above, the opening end surface 9A of the piston 9 contacts the side surface 13A of the plate 13 of the inner block 11 at the areas which are Fig. 3 are marked with dots. That is, the opening end surface 9A of the piston 9 does not contact the areas where the through holes 16 and 17 are formed as the first openings, but faces the projections 12A and 12B (end surfaces 12A1 and 12B1 thereof) of the brake pad 12, which enter the through holes 16 and 17 with a gap.

[0042] Furthermore, the claw portion 7 of the brake calliper 3 is in contact with the side surface 23A of the plate 23 of the outer block 21 at the areas which are Fig. 6 are marked with dots. That is, the claw portion 7 does not contact the areas where the through holes 26 and 27 are formed as second holes, but the projections 22A and 22B (end surfaces 22A1 and 22B1 thereof) of the brake pad 22, which enter the through holes 26 and 27, face the claw portion 7 with a gap.

[0043] In this regard, as in Fig. 8 and Fig. 9, the centers of gravity Ki, Ki of the through holes 16 and 17 and the centers of gravity Ko, Ko of the through holes 26 and 27 are shifted relative to each other (do not coincide) when the inner block 11 overlaps the outer block 21 in the axial direction of the disk. Consequently, the center of gravity position Li of the contact surface area (areas located in Fig. 3 are marked with dots) between the inner block 11 and the piston 9 and the center of gravity position Lo of the contact surface area (areas marked in Fig. 6 are marked with dots) between the outer block 21 and the claw section 7 according to the amount of displacement between the centers of gravity Ki, Ki and Ko, Ko as desired.

[0044] The Fig. 10 and Fig. 11 show a comparative example. Regarding the two drawings, Fig. 10 an inner block 11' of the comparative example, and Fig. 11 shows an outer block 21' of the comparative example. The inner block 11' of the comparative example is similar to the inner block 11 according to the embodiment except for the positions of the through holes 16' and 17' of the plate 13'. The outer block 21' of the comparative example is similar to the outer block 21 according to the embodiment except for the positions of the through holes 26' and 27' of the plate 23'. In the comparative example, components that are the same between the embodiment and the comparative example are denoted by the same reference numerals as used in the embodiment, with an apostrophe added.

[0045] In comparison of the Fig. 10 with Fig. 3, the through holes 16' and 17' in the inner block 11' of the comparative example are in the direction of the Y-axis closer to the side (lower side in Fig. 10) are arranged opposite to the side of the bridge portion 5 than the through holes 16 and 17 in the inner block 11 according to the embodiment. In this case, the center of gravity position Li' of the contact surface area (areas located in Fig. 10 are marked with dots) between the inner block 11' and the piston 9 according to the comparative example in the direction of the Y-axis closer to the side of the bridge section 5 (upper side in Fig. 10) is arranged as the center of gravity position Li of the contact surface area between the inner pad 11 and the piston 9 according to the embodiment. Thus, the center of gravity positions Li and Li' can be appropriately adjusted by adjusting the positions of the through holes 16, 17, 16', and 17'.

[0046] Assume that the center of gravity position of a disc contact surface of the inner pad 11 (11'), which is a contact surface between the brake pad 12, 12' and the disc 1, is Mi, and a line passing through the center of gravity position Mi and running parallel to the X-axis is a line segment aa. Further, assume that a line passing through the center of gravity position Li of the contact surface portion according to the embodiment, that is, the center of gravity Li of an adjacent surface of the plate 13 of the inner pad 11 that abuts against the piston 9 (opening end surface 9A thereof) and running parallel to the X-axis, is a line segment b1-b1.Further, assume that a line passing through the center of gravity position Li' of the contact surface portion according to the comparative example, that is, the center of gravity Li' of an adjacent surface of the plate 13' of the inner pad 11' abutting against the piston 9 (opening end surface 9a thereof) and parallel to the X-axis is a line segment b2-b2.

[0047] In this case, when the brake is applied (during braking), the inner pad 11, 11' receives a counterforce from the disc 1 to the brake pad 12, 12' side at the position of the line segment aa. Furthermore, the inner pad 11 of the embodiment receives the pressing force from the piston 9 at the position of the line segment b1-b1. In contrast, the inner pad 11' of the comparative example receives the pressing force from the piston 9 at the position of the line segment b2-b2.

[0048] Comparing the distance d1 between the center of gravity position Li (ie, the line segment b1-b1) of the contact surface portion and the center of gravity position Mi (ie, the line segment aa) of the disk contact surface according to the embodiment and the distance d2 between the center of gravity position Li' (ie, the line segment b2-b2) of the contact surface portion and the center of gravity position Mi (ie, the line segment aa) of the disk contact surface according to the comparative example, the distance d1 according to the embodiment can be made smaller than the distance d2 according to the comparative example (d1 < d2).

[0049] Thus, with the inner pad 11 according to the embodiment, the reaction force from the disc 1 side and the reaction force from the piston 9 side can be brought closer to each other by an amount corresponding to the amount by which the distance d1 decreases, and consequently, the brake pad 12 tends to wear evenly in the Y-axis direction. In contrast, with the inner pad 11' according to the comparative example, the reaction force from the disc 1 side and the reaction force from the piston 9 side are separated by an amount corresponding to the amount by which the distance d2 increases. Consequently, the brake pad 12' tends to wear excessively, for example, on the bridge portion 5 side in the Y-axis direction (upper side in the figure). Thus, the inner pad 11 according to the embodiment can reduce uneven wear of the brake pad 12 compared to the inner pad 11' according to the comparative example.

[0050] In comparison of the Fig. 11 and Fig. 5, the through holes 26' and 27' in the outer block 21' of the comparative example are located in the direction of the Y-axis closer to the side (lower side in Fig. 11) are arranged opposite to the side of the bridge section 5 than the through holes 26 and 27 in the outer block 21 according to the embodiment. In this case, the center of gravity position Lo' of the contact surface (areas located in Fig. 11 are marked with dots) between the outer block 21' and the piston 9 according to the comparative example in the direction of the Y-axis closer to the side of the bridge section 5 (upper side in Fig. 11) is arranged as the center of gravity position Lo of the contact surface between the outer pad 21 and the piston 5 according to the embodiment. Thus, the center of gravity positions Lo and Lo' can be adjusted as desired by adjusting the positions of the through holes 26, 27, 26', and 27'.

[0051] Here, assume that the center of gravity position of a disc contact surface of the outer pad 21, 21', which is a contact surface between the brake pad 22, 22' and the disc 1, is Mo (=Mi), and a line passing through the center of gravity position Mo and running parallel to the X-axis is a line segment aa. Further, assume that a line passing through the center of gravity position Lo of the contact surface portion according to the embodiment, that is, the center of gravity Lo of the adjacent surface of the plate 23 of the outer pad 21 abutting against the claw portion 7, and running parallel to the X-axis is a line segment c1-c1.Further, assume that a line passing through the center of gravity position Lo' of the contact surface area according to the comparative example, that is, the center of gravity Lo' of an adjacent surface of the plate 23' of the outer block 21' abutting against the claw portion 7 and parallel to the X-axis is a line segment c2-c2.

[0052] In this case, when the brake is applied (during braking), the outer pad 21, 21' receives a counterforce from the disc 1 to the brake pad 22, 22' side at the position of the line segment aa. Further, the outer pad 21 according to the embodiment receives the pressing force from the claw portion 7 at the position of the line segment c1-c1. In contrast, the outer pad 21' according to the comparative example receives the pressing force from the claw portion 7 at the position of the line segment c2-c2.

[0053] Here, comparing the distance e1 between the center of gravity position Lo (ie, the line segment c1-c1) of the contact surface portion and the center of gravity position Mo (ie, line segment aa) of the disk contact surface according to the embodiment and the distance e2 between the center of gravity position Lo' (ie, the line segment c2-c2) of the contact surface portion and the center of gravity position Mo (ie, the line segment aa) of the disk contact surface according to the comparative example, the distance e1 according to the embodiment can be made smaller than the distance e2 according to the comparative example (e1 < e2).

[0054] Thus, with the outer pad 21 according to the embodiment, a reaction force from the disc 1 side and a reaction force from the claw portion 7 side can be brought closer to each other by an amount corresponding to the amount by which the distance e1 decreases, and consequently, the brake pad 22 tends to wear uniformly in the Y-axis direction. In contrast, with the outer pad 21' according to the comparative example, the reaction force from the disc 1 side and the reaction force from the claw portion 7 are separated by an amount corresponding to the amount by which the distance e2 increases, and the brake pad 22' may wear greatly in the Y-axis direction, for example, on the bridge portion 5 side (upper side in the figure).Consequently, the outer pad 21 according to the embodiment can reduce uneven wear of the brake pad 22, compared to the outer pad 21' according to the comparative example.

[0055] Thus, the center of gravity position Li of the contact surface (areas that are in Fig. 3 are marked with dots) of the inner block 11 and the center of gravity position Lo of the contact surface (areas marked in Fig. 6) of the outer block 21 can be adjusted as desired by adjusting the positions of the centers of gravity Ki, Ki of the through holes 16 and 17 and the centers of gravity Ko, Ko of the through holes 26 and 27. In this case, according to the embodiment, it is not necessary to provide an intermediate member, such as an intermediate plate with a cutout portion, between the inner block 11 and the piston 9 and another intermediate member between the outer block 21 and the claw portion 7, and thus it is possible to reduce costs and improve productivity (ease of production).

[0056] According to the embodiment, the first and second openings for adjusting the center of gravity positions Li and Lo of the contact surfaces of the inner and outer pads 11 and 21 are, respectively, the through holes 16 and 17 and the through holes 26 and 27, which serve as gas vent holes for venting gas from the brake pads 12 and 22 when the brake pads 12 and 22 and the plates 13 and 23 are respectively attached to each other. In this regard, the through holes 16 and 17 and the through holes 26 and 27 are holes originally provided in the inner pad 11 and the outer pad 21, respectively. Consequently, there is no need to provide new holes as the first and second holes in the inner and outer pads 11 and 21. For this reason, too, it is possible to reduce costs and improve productivity.

[0057] The embodiment is configured such that the centers of gravity Ki, Ki of the through-holes 16 and 17 as the first holes are shifted in the Y-axis direction relative to the centers of gravity Ko, Ko of the through-holes 26 and 27 as the second holes. Thus, the center of gravity position Li of the contact surface between the inner pad 11 and the piston 9 (the opening end surface 9A thereof) and the center of gravity position Lo of the contact surface between the outer pad 21 and the claw portion 7 in the Y-axis direction can be adjusted as desired according to the shift amount in the Y-axis direction between the centers of gravity Ki, Ki of the through-holes 16 and 17 and the centers of gravity Ko, Ko of the through-holes 26 and 27.

[0058] According to the embodiment, the centers of gravity Ko, Ko of the through openings 26 and 27 are arranged as second openings closer to the side of the bridge section 5 (upper side in Fig. 1 to 9) of the brake calliper 3 in the direction of the Y-axis (up / down direction in Fig. 1 to 9) as the centers of gravity Ki, Ki of the through holes 16 and 17 as the first holes. Here, the claw section 7 extends in the direction of the Y-axis and away from the bridge section 5 (ie in Fig. 1 to 9 downward), with the bridge portion 5 side being defined as the front end side thereof. Thus, the center of gravity position Lo of the contact surface between the outer pad 21 and the claw portion 7 is likely to be located on the bridge portion 5 side in the Y-axis direction, compared with the center of gravity position Li of the contact surface between the inner pad 11 and the piston 9 (opening end surface 9A thereof).

[0059] In this regard, the center of gravity position Lo of the contact surface between the outer pad 21 and the claw portion 7 can be set away from the bridge portion 5 side by positioning the centers of gravity Ko, Ko of the through holes 26 and 27 closer to the bridge portion 5 side than the centers of gravity Ki, Ki of the through holes 16 and 17. Thus, the center of gravity position Lo of the contact surface between the outer pad 21 and the claw portion 7 and the center of gravity position Li of the contact surface between the inner pad 11 and the piston 9 (opening end surface 9A thereof) can be brought closer to each other (can finally be aligned) in the Y-axis direction. Thus, it is achieved that the brake pad 22 of the outer pad 21 and the brake pad 12 of the inner pad 11 tend to wear in the same way.

[0060] Fig. 12 to 14 show a second embodiment. The feature of the second embodiment is that the center of gravity of the abutting surface (contact surface area) of the inner pad plate abutting against the piston, the center of gravity of the abutting surface (contact surface area) of the outer pad plate abutting against the claw portion, and the centers of gravity of the contact surfaces (contact surface areas) between the inner and outer pad pads and the disc are aligned in the Y-axis direction. In the second embodiment, the same constituent elements as in the above-described first embodiment are designated by the same reference numerals as used in the first embodiment, and a description thereof will be omitted.

[0061] An inner block 31 according to the second embodiment is similar to the inner block 11 according to the first embodiment, except that the positions of through holes 33 and 34 in a plate 32 differ from the positions of the through holes 16 and 17 in the plate 13 according to the first embodiment. Specifically, according to the second embodiment, the through holes 33 and 34 in the inner block 31 are provided farther away (further down) from the bridge portion 5 than the through holes 16 and 17 according to the first embodiment, and closer (further up) to the bridge portion 5 than the through holes 16' and 17' according to the comparative example.

[0062] An outer block 41 according to the second embodiment is also similar to the outer block 21 according to the first embodiment, except that the positions of the through holes 43 and 44 in a plate 42 differ from the positions of the through holes 26 and 27 in the plate 23 according to the first embodiment. Specifically, according to the second embodiment, the through holes 43 and 44 in the outer block 41 are provided closer (further up) to the side of the bridge portion 5 than the through holes 26 and 27 according to the first embodiment and the through holes 26' and 27' according to the comparative example.

[0063] In this case, the second embodiment is further configured such that, when the inner block 31 protrudes in the axial direction of the disk toward the outer block 41, the centers of gravity (gravity centers or centers) Ki, Ki of the through holes 33 and 34 as first holes and the centers of gravity (gravity centers or centers) Ko, Ko of the through holes 43 and 44 as second holes are shifted relative to each other in the same manner as in the first embodiment. Fig. In Fig. 13, the inner block 31 (plate 32 thereof) is shown by a solid line, and the through holes 43 and 44 in the outer block 41, when the inner block 31 and the outer block 41 protrude in the axial direction of the disk, are shown by a two-dot chain line. On the other hand, in Fig.14, the outer block 41 (plate 42 thereof) is shown by a solid line, and the through holes 33 and 34 in the inner block 31 when the outer block 41 and the inner block 31 protrude in the axial direction of the disk are shown by a two-dot chain line.

[0064] The second embodiment is further arranged so that when the inner pad 31 protrudes toward the outer pad 41 in the axial direction of the disk, the centers of gravity Ko, Ko of the through holes 43 and 44 as second holes are arranged closer to the bridge portion 5 side of the caliper 3 in the Y-axis direction (ie, closer to the upper sides 13 and 14) than the centers of gravity Ki, Ki of the through holes 33 and 34 as first holes, in the same manner as in the first embodiment.Furthermore, the second embodiment is configured so that when the inner pad 31 protrudes toward the outer pad 41 in the disk axial direction, the center of gravity position (gravity center position or center position) Li of the contact surface area between the inner pad 31 and the piston 9 (opening end surface 9A thereof), the center of gravity position (gravity center position or center position) Lo of the contact surface area between the outer pad 41 and the claw portion 7, and the center of gravity positions Mi and Mo of the disk contact surfaces of the inner and outer pads 31 and 41, which are contact surfaces between the brake pads 12 and 22 and the disk 1, coincide in the Y-axis direction.

[0065] In other words, the arrangement is as follows: Assume that a line passing through the center of gravity positions Mi and Mo of the disk contact surfaces and running parallel to the X-axis is a line segment aa. Further, assume that a line passing through the center of gravity Li of the adjacent surface of the plate 32 of the inner pad 31 abutting against the piston 9 (opening end surface 9A thereof) and running parallel to the X-axis is a line segment bb, and assume that a line passing through the center of gravity Lo of the adjacent surface of the plate 42 of the outer pad 41 abutting against the claw portion 7 and running parallel to the X-axis is a line segment cc.Under this assumption, the through holes 33 and 34 as first holes and the through holes 43 and 44 as second holes are arranged so that when the inner block 31 projects toward the outer block 41 in the axial direction of the disk, the line segments aa, bb and cc coincide.

[0066] The disc brake according to the second embodiment is configured to align the line segments aa, bb, and cc using the inner and outer pads 31 and 41 described above. The basic operation of the second embodiment is not substantially different from that of the first embodiment described above.

[0067] Specifically, according to the second embodiment, the through holes 33, 34, 43, and 44 are arranged such that the line segments aa, bb, and cc coincide. With this arrangement, it is possible to reduce uneven wear of both the brake pad 22 of the outer block 41 and the brake pad 12 of the inner block 31. Thus, braking noise due to uneven wear can be reduced.

[0068] In describing the present invention according to the first embodiment, a case was taken as an example in which the inner block 11 has two through openings 16 and 17 as first openings and the outer block 21 has two through openings 26 and 27 as second openings. However, the present invention is not limited to the arrangement described above. For example, the inner block can be provided with exactly one first opening or three or more first openings. The outer block can also be provided, for example, with exactly one second opening or three or more second openings. Furthermore, the number of first openings and the number of second openings can differ from one another. This also applies to the second embodiment.

[0069] In describing the present invention according to the first embodiment, a case was taken as an example in which the through-holes 16 and 17 as first openings and the through-holes 26 and 27 as second openings are openings with a circular cross-section. However, the present invention is not limited to this. The first and second openings may be openings with a non-circular cross-section, for example, an oval, elliptical, rectangular, C-shaped, U-shaped, J-shaped, or ring-segment-like cross-section. This also applies to the second embodiment.

[0070] In describing the present invention according to the first embodiment, a case was taken as an example in which the through holes 16 and 17 as first holes are arranged symmetrically relative to the center in the rotational direction of the disk of the inner block 11 (ie, line-symmetrical with respect to a line passing through the center and running parallel to the Y-axis). The through holes 26 and 27 as second holes are also arranged symmetrically relative to the center in the rotational direction of the disk of the outer block 21 (ie, line-symmetrical with respect to a line passing through the center and running parallel to the Y-axis). However, the present invention is not limited to this. A plurality of first holes and / or a plurality of second holes may be arranged asymmetrically.

[0071] That is, a plurality of first openings and / or a plurality of second openings may be offset in the radial direction of the disc and / or the rotational direction of the disc, on both sides of the center in the rotational direction of the disc of the associated brake pad. Furthermore, if the number of first and / or second openings is exactly one, the center (center of gravity or center of gravity) of one opening may be offset in the radial direction of the disc and / or the rotational direction of the disc from the center of the associated friction pad in the rotational direction of the disc.

[0072] In describing the present invention according to the first embodiment, a case was exemplified where the first openings and the second openings are through holes 16 and 17 and through holes 26 and 27, respectively, which function as gas vent holes for venting gas from the brake pads 12 and 22 when the brake pads 12 and 22 and the plates 13 and 23 are respectively attached to each other. However, the present invention is not limited to this. The first openings and the second openings may be provided as openings different from the gas vent holes. In such a case, the first openings and the second openings may be through holes extending through the associated plates. Alternatively, the first and second openings may be closed recessed holes (bottom-closed holes) having a bottom.This also applies to the second embodiment.

[0073] In describing the present invention according to the first embodiment, a case in which a single piston 9 is provided in the inner base portion 4 of the brake caliper 3 was used as an example. However, the present invention is not limited to this. For example, two pistons may be provided in the inner base portion of the brake caliper to form a double-bore structure. Alternatively, three pistons may be provided in the inner base portion of the brake caliper. This also applies to the second embodiment.

[0074] Furthermore, the embodiments serve for illustration purposes, and the components shown in the various embodiments can, of course, be partially replaced or combined.

[0075] According to the embodiments described above, it is possible to reduce costs and improve productivity (production convenience).

[0076] Disc brakes based on the embodiments described above are intended to include, for example, the following aspects. That is, a disc brake according to a first aspect includes: a caliper configured to extend over an outer peripheral side of a disc that rotates together with a wheel, an inner pad and an outer pad configured to press the disc, a piston configured to press the inner pad, and a claw portion configured to press the outer pad. The inner pad has a first surface that contacts the disc when the inner pad presses the disc. The inner pad further has a second surface opposite to the first surface. The second surface has at least one first opening.The outer pad has a third surface that is in contact with the disk when the outer pad presses on the disk. The outer pad further has a fourth surface opposite to the third surface. The fourth surface has at least one second opening. The at least one first opening and the at least one second opening are arranged such that, when the inner pad protrudes toward the outer pad in the axial direction of the disk, a center of gravity of the at least one first opening and a center of gravity of the at least one second opening are shifted relative to each other. Consequently, the center of gravity position of the contact surface area between the inner pad and the piston (i.e., the center of gravity position of the adjacent surface) and the center of gravity position of the contact surface area between the outer pad and the claw portion (i.e.,The center of gravity (CG) position of the adjacent surface can be adjusted as desired according to the displacement between the center of gravity of the first opening and the center of gravity of the second opening. In this case, it is not necessary to provide an intermediate member, such as an intermediate plate provided with a cutout portion, between the inner pad and the piston, and another intermediate member between the outer pad and the claw portion. Consequently, it is possible to reduce costs and improve productivity.

[0077] According to a second aspect, based on the first aspect, the inner pad comprises a first brake pad forming the first surface and a first plate forming the second surface. The outer pad comprises a second brake pad forming the third surface and a second plate forming the fourth surface. The at least one first opening and the at least one second opening are gas venting openings for venting gas from the first brake pad and the second brake pad when the first brake pad and the first plate are attached to each other and when the second brake pad and the second plate are attached to each other. In this regard, the gas venting openings are openings originally provided in the inner pad and the outer pad. Consequently, there is no need to provide new openings as the first and second openings in the inner and outer pads.This is also why it is possible to reduce costs and improve productivity.

[0078] According to a third aspect based on the second aspect, when a direction connecting nose portions provided on opposite sides of the inner pad for receiving torque and a direction connecting nose portions provided on opposite sides of the outer pad for receiving torque are each defined as an X-axis, and when a direction perpendicular to the X-axis in the second and fourth surfaces of the first and second plates is defined as a Y-axis, the center of gravity of the at least one first opening is shifted in the Y-axis direction relative to the center of gravity of the at least one second opening. Thus, it is possible to adjust the center of gravity position of the contact surface area between the inner pad and the piston and the center of gravity position of the contact surface area between the outer pad and the claw portion in the Y-axis direction as desired.

[0079] According to a fourth aspect, based on the third aspect, the center of gravity of the at least one second opening is located closer to the bridge side of the caliper in the Y-axis direction than the center of gravity of the at least one first opening. Here, the claw portion extends in the Y-axis direction and away from the bridge, with the bridge side being defined as the front end side thereof. Consequently, the center of gravity position of the contact surface area between the outer pad and the claw portion is likely to be located on the bridge side in the Y-axis direction, compared to the center of gravity position of the contact surface area between the inner pad and the piston.

[0080] In this regard, the center of gravity position of the contact surface area between the outer pad and the claw portion can be adjusted away from the bridge side by positioning the center of gravity of the second opening closer to the bridge side than the center of gravity of the first opening. Thus, the center of gravity position of the contact surface area between the outer pad and the claw portion and the center of gravity position of the contact surface area between the inner pad and the piston can be brought closer to each other in the Y-axis direction (can eventually be aligned). Thus, the brake pad of the outer pad and the brake pad of the inner pad tend to exhibit the same wear.

[0081] According to a fifth aspect based on the third aspect, the at least one first opening and the at least one second opening are arranged such that, when the inner pad protrudes toward the outer pad in the axial direction of the disk, a line passing through a center of gravity of an adjacent surface of the first plate abutting the piston and running parallel to the X-axis, a line passing through a center of gravity of an adjacent surface of the second plate abutting the claw portion and running parallel to the X-axis, and lines passing through corresponding centers of gravity of the first and third surfaces and running parallel to the X-axis coincide. With this structure, it is possible to reduce uneven wear of both the brake pad of the outer pad and the brake pad of the inner pad. Thus, braking noise due to uneven wear can be reduced.

[0082] Although some embodiments of the present invention have been described above, the described embodiments of the present invention are for the purpose of simplifying the understanding of the present invention and are not intended to limit the present invention. Furthermore, structural elements described in the claims and specifications may be arbitrarily combined or omitted within a range that at least partially solves the problems set forth above or within a range that at least partially achieves the advantages. LIST OF REFERENCE SYMBOLS

[0083] 1 disc; 3 caliper; 5 bridge portion (bridge); 7 claw portion; 9 piston; 11, 31 inner pad; 12 brake pad; 13, 32 plate; 13A, 32A side surface (non-contact side surface); 14, 15 nose portion; 16, 17, 33, 34 through hole (first opening); 21 outer pad; 22 brake pad; 23, 42 plate; 23A, 42A side surface (non-contact side surface); 24, 25 nose portion; 26, 27, 43, 44 through hole (second opening); a, b, c parallel lines.

Claims

[1] Disc brake which has: a brake caliper (3) configured to extend over an outer peripheral side of a disc (1) rotating together with a wheel; an inner block (11, 31) and an outer block (21) arranged to press on the disc (1); a piston (9) having an opening end surface (9A) adapted to press the inner block (11); and a claw portion (7) adapted to press the outer block (21); in which the inner block (11) has a first surface which is in contact with the disc (1) when the inner block presses on the disc, and a second surface (13A) opposite the first surface, the second surface (13A) has at least one first opening (16, 17), the outer block (21) has a third surface which is in contact with the disc (1) when the outer block (21) presses on the disc (1), and a fourth surface (23A) opposite the third surface, the fourth surface (23A) has at least one second opening (26, 27), and the at least one first opening (16, 17) and the at least one second opening (26, 27) are arranged such that, when the inner block (11) protrudes in the axial direction of the disc (1) towards the outer block (21), a center of gravity (Ki) of the at least one first opening (16, 17) and a center of gravity (Ko) of the at least one second opening (26, 27) are displaced relative to one another, in which the inner block (11) has: a first brake pad (12) forming the first surface; and a first plate (13) forming the second surface (13A), wherein the outer block (21) has: a second brake pad (22) forming the third surface; and a second plate (23) forming the fourth surface (23A), and the at least one first opening (16, 17) and the at least one second opening (26, 27) each extend through the first plate (13) and the second plate (23), characterized by , that the first brake pad (12) has a projection (12A) which is received in the at least one first opening (16, 17), and the second brake pad (22) has a projection (22A) which is received in the at least one second opening (26, 27), wherein an end surface (12A1) of the projection (12A) of the first brake pad (12), which partially penetrates into the first opening (16, 17), is recessed from the second surface (13A) of the first plate (13), wherein during a brake application, the opening end surface (9A) of the piston (9) contacts the second surface (13A) of the inner pad (11) except for the first opening (16, 17), and wherein the opening end surface (9A) of the piston (9) is opposite to, but does not contact, the end surface (12A1) of the projection (12A) of the first brake pad (12). [2] A disc brake according to claim 1, wherein, when a direction connecting nose portions (14, 15) respectively provided on opposite sides of the inner pad (11) for receiving a torque and a direction connecting nose portions (24, 25) respectively provided on opposite sides of the outer pad (21) for receiving a torque are each defined as the X-axis and a direction perpendicular to the X-axis in the second and fourth surfaces of the first and second plates is defined as the Y-axis, the center of gravity (Ki) of the at least one first opening (16, 17) is shifted in the direction of the Y-axis relative to the center of gravity (Ko) of the at least one second opening (26, 27). [3] Disc brake according to claim 2, wherein the center of gravity (Ko) of the at least one second opening (26, 27) is arranged in the direction of the Y-axis closer to the side of the bridge (5) of the brake caliper than the center of gravity (Ki) of the at least one first opening (16, 17). [4] A disc brake according to claim 2, wherein the at least one first opening (16, 17) and the at least one second opening (26, 27) are arranged such that when the inner pad (11) projects in the axial direction of the disc (1) toward the outer pad (21), a line passing through a center of gravity of an adjacent surface of the first plate (13) abutting against the piston (9) and running parallel to the X-axis, a line passing through a center of gravity of an adjacent surface of the second plate (23) abutting against the claw portion (7) and running parallel to the X-axis, and lines passing through corresponding centers of gravity of the first and third surfaces and running parallel to the X-axis coincide.

Images