JP2013155799A - Disc brake for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and weight of a caliper body while preventing the eccentric wear of a brake pad, in a disc brake for a vehicle in which a first hydraulic chamber and a second hydraulic chamber are mutually independently formed in the caliper body, and a brake is operated according to the application of hydraulic pressure to at least one of the first and second hydraulic chambers.SOLUTION: A large diameter piston 37 in which a bottomed cylinder hole 33 having a large diameter hole part 33a and a small diameter hole part 33b on the same axis is formed at the caliper body 20 so that at least a part of the small diameter hole part 33b is arranged within an axial width of the large diameter hole part 33a, and which is liquid-tightly and slidably fit to the large diameter hole part 33a, and a small diameter piston 38 which is liquid-tightly and slidably fit to the small diameter hole part 33b are coaxially linked and connected to each other, a first hydraulic chamber 31 is formed between the large diameter piston 37 and the caliper body 20, and a second hydraulic chamber 32 is formed between the small diameter piston 38 and the caliper body 20.

Description

  According to the present invention, in the caliper body, the first hydraulic chamber connected to the first hydraulic pressure generating means for outputting the hydraulic pressure corresponding to the operation of the first brake operator and the operation of the second brake operator are used. A second hydraulic pressure chamber connected to the second hydraulic pressure generating means for outputting the hydraulic pressure is formed independently of each other, and the hydraulic pressure acts on at least one of the first and second hydraulic pressure chambers. The present invention relates to a vehicle disc brake that operates a brake.

  There is known a motorcycle equipped with an interlocking brake system in which the front and rear disc brakes are operated in conjunction with each other by operating one brake operator. In such an interlocking brake system, a caliper for the front wheels is known. A first hydraulic chamber connected to a front master cylinder that outputs hydraulic pressure corresponding to the operation of the brake lever to the body, and a first master cylinder connected to a rear master cylinder that outputs hydraulic pressure corresponding to the depression operation of the brake pedal. The two hydraulic chambers are formed independently of each other, and the large-diameter first piston on which the hydraulic pressure in the first hydraulic chamber acts, and the small-diameter second piston on which the hydraulic pressure in the second hydraulic chamber acts By connecting and connecting the brake pads in a coaxial manner, even if the brake lever or brake pedal is operated alone, it is possible to prevent the biasing force from acting on the brake pads and Disc brake so as to prevent uneven wear, are known in the patent document 1.

JP-A-2-216353

  However, in the one disclosed in the above-mentioned Patent Document 1, a large-diameter first cylinder hole whose one end is opened to the brake disc side so that the first piston is slidably fitted, and the second piston are slid. A small-diameter second cylinder hole that is freely fitted and arranged coaxially with the first cylinder hole is between the other end of the first cylinder hole and one end of the second cylinder hole. The caliper body is provided so as to form a step portion along a plane orthogonal to the caliper body, and the caliper body is enlarged in the direction along the axis of the first and second cylinder holes, resulting in an increase in weight.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle disc brake that can reduce the size and weight of the caliper body while preventing uneven wear of the brake pads.

  In order to achieve the above object, according to the present invention, a first hydraulic pressure chamber connected to a first hydraulic pressure generating means for outputting a hydraulic pressure corresponding to an operation of the first brake operator and a second hydraulic pressure chamber are provided in the caliper body. A second hydraulic pressure chamber connected to the second hydraulic pressure generating means for outputting the hydraulic pressure corresponding to the operation of the brake operator is formed independently of each other, and a liquid is provided in at least one of the first and second hydraulic pressure chambers. A bottomed cylinder hole having a large-diameter hole that opens toward the brake disk and a small-diameter hole that is smaller in diameter than the large-diameter hole in a vehicle disc brake that brakes in response to pressure. However, the caliper body is provided so that at least a part of the small-diameter hole portion is disposed within the axial width of the large-diameter hole portion, and the large-diameter hole portion is liquid-tightly and slidably fitted into the large-diameter hole portion. A fluid-tight and slidable fitting with the diameter piston and the small-diameter hole A small-diameter piston is coaxially linked and connected, a first hydraulic chamber is formed between the large-diameter piston and the caliper body, and a second hydraulic chamber is formed between the small-diameter piston and the caliper body. Is the first feature.

  In addition to the configuration of the first feature, the present invention has a second feature that the large-diameter piston and the small-diameter piston are formed coaxially and integrally.

  According to the present invention, in addition to the configuration of the first or second feature, a piston seal attached to the inner periphery of the small-diameter hole portion so as to be in sliding contact with the outer periphery of the small-diameter piston includes an axis of the large-diameter hole portion. A third feature is that the first feature is disposed within the direction width.

  In the present invention, in addition to any one of the first to third features, the caliper body is provided with first and second bleeder holes that individually communicate with the first and second hydraulic pressure chambers and are independent of each other. The fourth characteristic is that

  Furthermore, in addition to any of the configurations of the first to fourth features, the present invention provides that the large-diameter piston is fluid-tight and slidable in the large-diameter hole by opening one end to the brake disc side. A cylindrical outer fitting tube portion that fits into the first fitting portion, a first flange portion that projects radially inward from the other end of the outer fitting tube portion, and the outer fitting tube from the inner periphery of the first flange portion. An inner cylindrical portion that extends to an axially intermediate portion of the portion and a second flange portion that projects radially inward from the tip of the inner cylindrical portion, and the small-diameter piston includes a second piston A cylindrical inner fitting tube portion that is integrally connected to the inner periphery of the flange portion and fluidly and slidably fits into the small diameter hole portion, and an end that closes the other end of the inner fitting tube portion The wall portion is integrally formed into a bottomed cylindrical shape, and the large-diameter piston and the small-diameter piston are formed by molding a single plate material. It is referred to as the fifth feature.

  The brake lever 15 of the embodiment corresponds to the first brake operator of the present invention, the brake pedal 16 of the embodiment corresponds to the second brake operator of the present invention, and the front wheel master cylinder MF of the embodiment. Corresponds to the first hydraulic pressure generating means of the present invention, and the rear wheel master cylinder MR of the embodiment corresponds to the second hydraulic pressure generating means of the present invention.

  According to the first feature of the present invention, the bottomed cylinder hole provided in the caliper body has a large-diameter hole that opens to the brake disc side, and a small-diameter hole that is smaller in diameter than the large-diameter hole. A large-diameter piston that is arranged coaxially so that at least a part of the small-diameter hole is disposed within the axial width of the large-diameter hole, and fits in a liquid-tight and slidable manner in the large-diameter hole; A first hydraulic chamber is formed between the caliper bodies, and the second liquid is interposed between the small-diameter piston and the caliper body, which are fluid-tightly and slidably fitted in the small-diameter hole and coaxially linked and connected to the large-diameter piston. Since the pressure chamber is formed, the axial length of the cylinder hole having the large-diameter hole portion and the small-diameter hole portion can be set short, the caliper body can be downsized in the direction along the axis of the cylinder hole, and the caliper body weight can be reduced. Can be achieved.

  According to the second feature of the present invention, since the large-diameter piston and the small-diameter piston are integrally formed, the number of parts can be reduced and the cost can be reduced.

  According to the third feature of the present invention, the piston seal slidably contacting the outer periphery of the small diameter piston is mounted on the inner periphery of the small diameter hole so as to be disposed within the axial width of the large diameter hole. Even if the axial length of the small-diameter hole is set short, the length of the small-diameter hole can be kept small by always bringing the piston seal into sliding contact with the outer periphery of the small-diameter piston for the required sliding stroke of the small-diameter piston. The caliper body can be further downsized in the direction along the axis of the cylinder hole.

  According to the fourth aspect of the present invention, the caliper body is provided with first and second bleeder holes that are individually connected to the first and second hydraulic pressure chambers, so that the first and second liquids are provided. Even if the pressure chamber is made completely independent and a hydraulic pressure change occurs in one of the first and second hydraulic pressure chambers, the influence is hardly exerted on the other hydraulic pressure chamber.

  Furthermore, according to the fifth feature of the present invention, the large-diameter piston has a cylindrical outer fitting cylindrical portion and an inner cylindrical portion arranged in the outer fitting cylindrical portion, and has a double cylindrical shape. Since it is configured, rigidity can be increased, and a small-diameter piston having a bottomed cylindrical shape is integrally connected to the inner periphery of the second flange provided in the large-diameter piston so that there is one large-diameter piston and one small-diameter piston. Since it is formed by molding a plate material, the cost can be reduced.

It is a hydraulic-pressure circuit diagram which shows the structure of the brake device of 1st Embodiment. It is a partially cutaway front view of the caliper body and bracket of the disc brake for front wheels. FIG. 3 is a view taken in the direction of arrow 3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. It is sectional drawing corresponding to FIG. 4 of 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  The first embodiment of the present invention will be described with reference to FIGS. 1 to 4. First, in FIG. 1, the rotation of the front wheel of the motorcycle can be braked by a front wheel disc brake BF1, and this front wheel disc is shown. The brake BF1 includes a brake disc 11 that rotates together with the front wheels, and a caliper 12A that is disposed so as to straddle the outer periphery of the brake disc 11. The rotation of the rear wheel can be braked by a rear wheel disc brake BR. The rear wheel disc brake BR is arranged so as to straddle the brake disc 13 rotating together with the rear wheel and the outer periphery of the brake disc 13. Caliper 14 to be provided.

  The front wheel disc brake BF1 is acted on by the hydraulic pressure from the front wheel master cylinder MF as the first hydraulic pressure generating means for generating the hydraulic pressure in response to the operation of the brake lever 15 as the first brake operator. The hydraulic pressure from the rear wheel master cylinder MR as the second hydraulic pressure generating means for generating the hydraulic pressure in response to the operation of the brake pedal 16 as the second brake operator acts via the delay valve 17 and is used for the front wheel. The disc brake BF1 is braked according to the operation of at least one of the brake lever 15 and the brake pedal 16. The hydraulic pressure from the rear wheel master cylinder MR acts on the rear wheel disc brake BR via the proportional pressure reducing valve 18.

  2 to 4, the front wheel disc brake BF1 is configured according to the present invention, and the caliper 12A is disposed so as to straddle the outer periphery of the brake disc 11. The large-diameter piston 37 and the small-diameter piston 38 are slidably fitted in a direction parallel to the rotation axis of the brake disk 11.

  The caliper body 20 includes an action part 20a and a reaction part 20b disposed on both sides of the brake disk 11, and a bridging part 20c that connects the action part 20a and the reaction part 20b across the brake disk 11. Become. The caliper body 20 is slidably supported by a fixed bracket 22 via a pair of sliding pins 23 and 24 extending in parallel with the rotation axis of the front wheel.

  Friction pads 25 and 26 are interposed between the action part 20a and the brake disk 11 and between the reaction part 20b and the brake disk 11, respectively. The friction pads 25 and 26 are attached to the back plates 27 and 28, respectively. Lining 29, 30 is provided on the surface of the brake disc 11 side.

  In the working portion 20a of the caliper body 20, a first hydraulic pressure chamber 31 connected to the front wheel master cylinder MF and a second hydraulic pressure chamber connected to the rear wheel master cylinder MR via the delay valve 17 are provided. 32 are formed independently of each other.

  The acting portion 20a has a bottomed cylinder hole 33 coaxially having a large diameter hole 33a that opens toward the brake disc 11 and a small diameter hole 33b that is smaller in diameter than the large diameter hole 33a. At least a part of the small-diameter hole 33b is provided within the axial width of the large-diameter hole 33a while the central axis is parallel to the rotation axis of the brake disk 11.

  Thus, the large-diameter hole 33 a is provided in the action portion 20 a of the caliper body 20 so that one end is opened to the brake disc 11 side and the other end is closed by the end wall 34. One end is opened to the cylindrical projection 35 and the end wall 34 provided integrally with the action portion 20a so as to protrude into the large-diameter hole portion 33a toward the large-diameter hole portion 33a, and the other. A small diameter hole 33b whose end is closed by the end wall 35 is formed.

  A large-diameter piston 37 is slidably fitted in the large-diameter hole portion 33a of the cylinder hole 33, and a small-diameter piston 38 that is coaxially linked and connected to the large-diameter piston 37 is slid in the small-diameter hole portion 33b. In this embodiment, the large-diameter piston 37 and the small-diameter piston 38 are coaxially and integrally formed by molding a single plate material.

  The large-diameter piston 37 is formed in a cylindrical shape having one end opened on the brake disc 11 side, and is fitted with an outer fitting cylinder portion 37a that is liquid-tightly and slidably fitted into the large-diameter hole portion 33a. A first flange portion 37b projecting radially inward from the other end of the outer fitting cylinder portion 37a, and an inner side extending from the inner periphery of the first flange portion 37b to the axially intermediate portion of the outer fitting cylinder portion 37a. A cylindrical portion 37c and a second flange portion 37d that projects radially inward from the tip of the inner cylindrical portion 37c and faces the tip of the protrusion 35 are integrally provided. The small-diameter piston 38 is a cylindrical inner fitting cylinder that is integrally connected to the inner periphery of the second flange portion 37d of the large-diameter piston 37 and that is liquid-tightly and slidably fitted into the small-diameter hole portion 33b. A portion 38a and an end wall portion 38b that closes the other end of the inner fitting tube portion 38a are integrally formed to have a bottomed cylindrical shape, and are slidably fitted into the small diameter hole portion 33b. .

  Thus, the first hydraulic chamber 31 is formed outside the small-diameter piston 38 and between the large-diameter piston 37 and the action portion 20a of the caliper body 20, and the second hydraulic chamber 32 is formed by the small-diameter piston 38 and the caliper body. It is formed between 20 action parts 20a.

  An annular dust seal 39 that is in sliding contact with the outer periphery of the fitting cylinder portion 37 a of the large-diameter piston 37, and the dust seal 39 and the first hydraulic chamber 31 are disposed on the inner periphery of the large-diameter hole portion 33 a in the cylinder hole 33. Then, an annular piston seal 40 slidably contacted with the outer periphery of the fitting cylinder portion 37a is attached. An annular piston seal 41 that slides on the outer periphery of the small-diameter piston 38 is attached to the inner periphery of the small-diameter hole portion 33b in the cylinder hole 33. The piston seal 41 is connected to the large-diameter hole portion 33a. Arranged within the axial width.

  In addition, a first input port 42 communicating with the first hydraulic pressure chamber 31 is provided in the action portion 20a of the caliper body 20 so as to be connected to the front wheel master cylinder MF, and also communicated with the second hydraulic pressure chamber 32. A second input port 43 is provided so as to be connected to the delay valve 17.

  Further, the action portion 20a of the caliper body 20 is provided with first and second bleeder holes 44 and 45 that are individually connected to the first and second hydraulic pressure chambers 31 and 32, respectively. A first bleeder screw 46 is screwed into the bleeder hole 44, and a second bleeder screw 47 is screwed into the second bleeder hole 45.

  Next, the operation of the first embodiment will be described. The caliper body 20 of the front wheel disc brake BF1 has a large-diameter hole portion 33a that opens to the brake disc 11 side, and a smaller diameter than the large-diameter hole portion 33a. A bottomed cylinder hole 33 coaxially with a small diameter hole portion 33b is provided so as to dispose at least a part of the small diameter hole portion 33b within the axial width of the large diameter hole portion 33a. A large-diameter piston 37 that is liquid-tightly and slidably fitted to the portion 33a and a small-diameter piston 38 that is liquid-tightly and slidably fitted to the small-diameter hole portion 33b are coupled and connected coaxially, A first hydraulic chamber 31 is formed between the large-diameter piston 37 and the caliper body 20, and a second hydraulic chamber 32 is formed between the small-diameter piston 38 and the caliper body 20, so that the large-diameter hole portion 33a and Diameter hole portion 33b can be set short axial length of the cylinder hole 33 having a caliper body 20 is downsized in a direction along the axis of the cylinder bore 33, it is possible to weight reduction of the caliper body 20.

  Further, since the large-diameter piston 37 and the small-diameter piston 38 are coaxially and integrally formed, it is possible to reduce the number of parts and to reduce the cost.

  Further, since the piston seal 41 mounted on the inner periphery of the small diameter hole 33b so as to be in sliding contact with the outer periphery of the small diameter piston 38 is disposed within the axial width of the large diameter hole 33a, the small diameter hole 33b. Even if the axial length is set to be short, the length of the small-diameter hole 33b is kept small by always bringing the piston seal 41 into sliding contact with the outer periphery of the small-diameter piston 38 for the required sliding stroke of the small-diameter piston 38. The caliper body 20 can be further downsized in the direction along the axis of the cylinder hole 33.

  Since the caliper body 20 is provided with first and second bleeder holes 44 and 45 that are individually connected to the first and second hydraulic pressure chambers 31 and 32 and are independent of each other, the first and second hydraulic pressure chambers 31 and 32 Even if a change in hydraulic pressure occurs in one of the first and second hydraulic pressure chambers 31 and 32, the influence hardly affects the other hydraulic pressure chamber.

  Furthermore, since the large-diameter piston 37 has a cylindrical outer fitting cylinder part 37a and an inner cylinder part 37c arranged in the outer fitting cylinder part 37a, the large-diameter piston 37 is configured in a double cylinder shape, so that rigidity is increased. The large-diameter piston 37 and the small-diameter piston 38 are formed as a single plate so that the small-diameter piston 38 having a bottomed cylindrical shape can be integrally connected to the inner periphery of the second flange portion 37d of the large-diameter piston 37. Therefore, the cost can be reduced.

  The second embodiment of the present invention will be described with reference to FIG. 5, but the parts corresponding to the first embodiment are only shown with the same reference numerals, and the detailed description is omitted. To do.

  The front wheel disc brake BF2 includes a brake disc 11 and a caliper 12B arranged so as to straddle the outer periphery of the brake disc 11. The caliper 12B is arranged to straddle the outer periphery of the brake disc 11. A large-diameter piston 50 and a small-diameter piston 51 are fitted to the body 20 so as to be slidable in a direction parallel to the rotation axis of the brake disk 11.

  The action part 20a of the caliper body 20 has a bottomed bottom having a large-diameter hole 33a and a small-diameter hole 33b having a smaller diameter than the large-diameter hole 33a in the same manner as in the first embodiment. The cylinder hole 33 is provided so that at least a part of the small-diameter hole 33b is disposed in the large-diameter hole 33a.

  A large-diameter piston 50 is slidably fitted in the large-diameter hole 33a of the cylinder hole 33, and a small-diameter piston 51 that is coaxially linked and connected to the large-diameter piston 50 is slid in the small-diameter hole 33b. The large diameter piston 50 and the small diameter piston 51 are coaxially and integrally formed.

  The large-diameter piston 50 includes a fitting cylinder portion 50a that is fitted in the large-diameter hole portion 33a in a fluid-tight and slidable manner, and a radially inner portion from one end of the fitting cylinder portion 50a on the brake disc 121 side. The small-diameter piston 51 is integrally formed with the inner periphery of the flange 50b of the large-diameter piston 50 and is formed into a bottomed cylindrical shape, and has a small-diameter hole 33b. And is slidably fitted to.

  Thus, a first hydraulic pressure chamber 52 is formed outside the small diameter piston 51 and between the large diameter piston 37 and the action portion 20a of the caliper body 20, and between the small diameter piston 51 and the action portion 20a of the caliper body 20. A second hydraulic chamber 32 is formed.

  On the inner periphery of the large-diameter hole portion 33 a in the cylinder hole 33, an annular dust seal 39 slidably contacting the outer periphery of the fitting cylinder portion 50 a in the large-diameter piston 50 is disposed between the dust seal 39 and the first hydraulic pressure chamber 52. An annular piston seal 40 is attached. Further, an annular piston seal 41 slidably in contact with the outer periphery of the small diameter piston 51 is attached to the inner periphery of the small diameter hole portion 33b. The piston seal 41 is within the axial width of the large diameter hole portion 33a. Be placed.

  In addition, a first input port 42 communicating with the first hydraulic pressure chamber 31 is provided in the action portion 20a of the caliper body 20 so as to be connected to the front wheel master cylinder MF (see the first embodiment). A second input port 43 (see the first embodiment) communicating with the second hydraulic pressure chamber 32 is provided so as to be connected to the delay valve 17 (see the first embodiment).

  Further, the working portion 20a of the caliper body 20 communicates with the second fluid pressure chamber 32 and the second bleeder screw 47 with which the second bleeder screw 47 is screwed, and communicates with the first fluid pressure chamber 52 and the first bleeder screw. A first bleeder hole 44 (see the first embodiment) to which 46 (see the first embodiment) is screwed is provided independently of each other.

  The same effect as that of the first embodiment can be obtained also by the second embodiment.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

  For example, the second brake operator can be replaced by a brake lever instead of a brake pedal, and the first hydraulic pressure generating means can be a rear wheel master cylinder, and the second hydraulic pressure generating means can be a front wheel master cylinder. It is also possible.

DESCRIPTION OF SYMBOLS 11 ... Brake disc 15 ... Brake lever 16 as a first brake operator 16 ... Brake pedal 20 as a second brake operator ... Caliper bodies 31, 52 ... First hydraulic chamber 32 ... second hydraulic chamber 33 ... cylinder hole 33a ... large diameter hole 33b ... small diameter hole 37, 50 ... large diameter piston 37a ... outside fitting cylinder 37b ... -1st collar part 37c ... Inner cylindrical part 37d ... 2nd collar part 38,51 ... Small diameter piston 38a ... Inner fitting cylinder part 38b ... End wall part 41 ... Piston seal 44 ... 1st bleeder hole 45 ... 2nd bleeder hole MF ... Front wheel master cylinder MR as first hydraulic pressure generating means ... Rear wheel master cylinder as second hydraulic pressure generating means

Claims (5)

  In the caliper body (20), a first hydraulic pressure chamber (31, 52) connected to first hydraulic pressure generating means (MF) for outputting a hydraulic pressure according to the operation of the first brake operator (15), and A second hydraulic pressure chamber (32) connected to the second hydraulic pressure generating means (MR) for outputting the hydraulic pressure according to the operation of the second brake operator (16) is formed independently of each other, And a large-diameter hole (33a) that opens to the brake disc (11) side in a vehicle disc brake that operates in response to hydraulic pressure acting on at least one of the second hydraulic chambers (31, 52; 32). And a bottomed cylinder hole (33) having a small diameter hole portion (33b) having a diameter smaller than that of the large diameter hole portion (33a), and at least part of the small diameter hole portion (33b) is a large diameter hole portion. (33a) so as to be disposed within the axial width of the caliper A large-diameter piston (37, 50) that is liquid-tightly and slidably fitted in the large-diameter hole (33a), and is liquid-tight in the small-diameter hole (33b). A small-diameter piston (38, 51) that is slidably fitted is coaxially linked and connected, and a first hydraulic chamber (31, 52) is provided between the large-diameter piston (37, 50) and the caliper body (20). ) And a second hydraulic pressure chamber (32) is formed between the small diameter piston (38, 51) and the caliper body (20).   The disk brake for a vehicle according to claim 1, wherein the large-diameter piston (37, 50) and the small-diameter piston (38, 51) are coaxially and integrally connected.   A piston seal (41) mounted on the inner periphery of the small diameter hole (33b) so as to be in sliding contact with the outer periphery of the small diameter piston (38, 51) is within the axial width of the large diameter hole (33a). The vehicular disc brake according to claim 1, wherein the disc brake is disposed on the vehicle.   The caliper body (20) is provided with first and second bleeder holes (44, 45) that individually communicate with the first and second hydraulic pressure chambers (31, 52; 32) and are independent of each other. The disc brake for vehicles according to any one of claims 1 to 3.   A cylindrical outer fitting cylinder portion in which the large-diameter piston (37) has one end opened to the brake disc (11) side and is fitted in the large-diameter hole portion (33a) in a liquid-tight and slidable manner. (37a), a first flange portion (37b) projecting radially inward from the other end of the outer fitting tube portion (37a), and the outer fitting tube from the inner periphery of the first flange portion (37b). An inner cylindrical portion (37c) extending to the axially intermediate portion of the portion (37a) and a second flange portion (37d) projecting radially inward from the tip of the inner cylindrical portion (37c) are integrally provided. The small-diameter piston (38) is configured in such a manner that one end thereof is integrally connected to the inner periphery of the second flange portion (37d) and is fitted into the small-diameter hole portion (33b) in a liquid-tight and slidable manner. And an end wall portion (38b) that closes the other end of the inner fitting tube portion (38a). 5. The structure according to claim 1, wherein the large-diameter piston (37) and the small-diameter piston (38) are formed by molding a single plate material. The vehicle disc brake according to claim 1.

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