JP7475305B2 - Vehicle disc brakes - Google Patents

Description

The present invention relates to a vehicle disc brake mounted on a moving vehicle such as an automobile or two- or three-wheeled motor vehicle, and more specifically to a vehicle disc brake equipped with a pad return spring that biases the friction pad toward the opposite side of the disc rotor when braking is released.

In the past, in vehicle disc brakes, a pad return spring was attached to the radially outer side of a pair of friction pads arranged on both sides of the disc rotor, which biases the pair of friction pads toward the opposite side of the disc rotor when braking is released, to prevent the friction pads from dragging. In addition, some pad return springs were formed by bending wire, and the center of the wire was folded back to form a folded part that was located on the outer periphery of the disc rotor and in the middle of the pair of friction pads, a pair of spring parts that extend away from each other from both ends of the folded part toward the radially outer parts of the pair of friction pads, and an engagement part that was bent at the tip of each spring part and inserted into an engagement hole formed on the radially outer part of the friction pad (see, for example, Patent Document 1).

JP 2015-148317 A

However, in the above-mentioned Patent Document 1, the engagement holes formed in the friction pads are formed with a diameter that minimizes the gap between the engagement parts and the pad return springs so that the engagement parts of the pad return springs can be engaged without rattling. As a result, when assembling the pad return springs to the pair of friction pads, it is time-consuming to insert the pair of engagement parts into each of the engagement holes while biasing the pair of spring parts in a direction that brings them closer to each other.

The present invention aims to provide a vehicle disc brake that improves the assembly of the pad return spring.

In order to achieve the above object, the vehicle disc brake of the present invention is a vehicle disc brake in which a pair of friction pads are arranged on both sides of a disc rotor, and a pad return spring is attached to the radially outer side of the pair of friction pads formed by attaching a lining to the disc rotor side of a back plate, and the pair of friction pads are characterized in that a pair of engagement grooves elongated in the disc circumferential direction are formed on the radially outer side of the disc rotor of the back plate, which engage the pad return spring, and the pad return spring is formed by bending an elongated member, folding back the center of the elongated member, and has a folded part that is positioned on the outer periphery of the disc rotor and in the middle of the pair of friction pads, a pair of spring parts that extend from both ends of the folded part in directions away from each other toward the pair of friction pads, and a pair of engagement parts that extend further away from the pair of spring parts and engage with the engagement grooves, respectively.

It is also preferable that the pair of engagement grooves are formed in a V-shape with the depth of the groove gradually increasing toward the center.

Furthermore, the pair of engagement parts preferably include a pair of straight parts that extend linearly from the pair of spring parts in directions that move away from each other in the disk axial direction, and a pair of curved parts that extend from the pair of straight parts in a convex curve in the direction that moves away from each other, with the tips approaching each other, and the pair of curved parts preferably engage with the pair of engagement grooves, respectively.

According to the vehicle disc brake of the present invention, when assembling the pad return spring to the friction pad, the orientation of the pad return spring is such that the folded portion faces the center of the friction pad and the pair of spring portions faces the side of the friction pad, and the pair of spring portions is pressed to bring the pair of spring portions and the pair of engaging portions close to each other, and then the folded portion is positioned on the outer periphery of the disc rotor and in the middle position of the pair of friction pads, and the pair of engaging portions are positioned in positions corresponding to the pair of engaging grooves. After that, the pressure applied to the pair of spring portions is released, and the pair of engaging portions can be engaged with the pair of engaging grooves, respectively. This makes it possible to easily assemble the pad return spring to the friction pad.

In addition, the pair of engagement grooves are formed in a V-shape with the depth of the groove gradually increasing toward the center, which increases the contact area between the engagement portion and the engagement groove, allowing the pad return spring to be securely attached to the friction pad.

Furthermore, the pair of engagement parts each have a pair of straight parts that extend linearly from the pair of spring parts in directions that move away from each other in the disk axial direction, and a pair of curved parts that extend from the pair of straight parts in a convex curve in the direction that moves further away from each other, with their tips approaching each other. The pair of curved parts each engage with the pair of engagement grooves, so that when assembling the pad return spring to the friction pad, the spring parts can be easily pressed by pinching the corners formed between each spring part and the straight parts. Furthermore, the convexly curved curved parts can be engaged with the engagement grooves, which further improves the ease of assembly of the pad return spring.

1 is a partially cutaway plan view of a vehicle disc brake showing one embodiment of the present invention; FIG. 2 is an enlarged cross-sectional view of a main portion of the vehicle disc brake. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1 is a partially cutaway rear view of a vehicle disc brake showing an example of the present invention. FIG. FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 5 .

Figures 1 to 6 show an example of a vehicle disc brake of the present invention. Arrow A indicates the direction of rotation of the disc rotor that rotates together with the wheel when the vehicle moves forward, and the disc rotation outward and inward sides described below refer to the direction when the vehicle moves forward.

This vehicle disc brake 1 is composed of the disc rotor 2, a caliper bracket 3 fixed to the vehicle body on one side of the disc rotor 2, a caliper body 5 supported on the caliper support arms 3a, 3a of the caliper bracket 3 so as to be movable in the disc axial direction via a pair of slide pins 4, 4, and a pair of friction pads 6, 6 arranged opposite each other on the inside of the action part 5a and reaction part 5b of the caliper body 5, sandwiching the disc rotor 2 therebetween. A pad return spring 7 is attached to the friction pads 6, 6 to bias the friction pads 6, 6 toward the opposite side of the disc rotor when braking is released.

The caliper body 5 is composed of the above-mentioned action part 5a and reaction part 5b arranged on both sides of the disk rotor 2, and a bridge part 5c that connects them across the outer edge of the disk rotor 2. The action part 5a has a cylinder hole 5d that opens to the disk rotor 2 side. A bottomed cylindrical piston 8 is housed in the cylinder hole 5d via a piston seal 9 and a dust seal 10, and the piston 8 moves in the cylinder hole 5d in the disk axial direction by the hydraulic pressure supplied to the hydraulic pressure chamber 11 defined at the bottom of the cylinder hole. In addition, slide pin mounting arms 5e, 5e are protruding from the side of the action part 5a, and the above-mentioned slide pin 4 is attached to the tip of each slide pin mounting arm 5e by a mounting bolt 4a.

The caliper bracket 3 includes a vehicle body mounting portion 3b that is attached to the vehicle body on one side of the disc rotor 2, and the caliper support arms 3a, 3a that protrude from the disc inlet side and disc outlet side of the vehicle body mounting portion 3b. The caliper support arms 3a, 3a protrude from the radially outer side of the disc rotor 2 on the other side of the disc rotor 2 while sandwiching both sides of the bridge portion 5c, and extend toward the center of the disc along the side wall of the reaction portion 5b on the other side of the disc rotor 2. The tips of the caliper support arms 3a, 3a are connected by a tie rod 3c, which increases the rigidity of both caliper support arms 3a, 3a on which braking torque is applied. Furthermore, each caliper support arm 3a, 3a is provided with a guide hole 3d that accommodates the slide pin 4 described above, and each caliper support arm 3a, 3a is provided with four pad guide grooves 3e that face each other on each side of the disc rotor 2. A pair of pad guide grooves 3e that face each other on the side of the disc rotor 2 are formed with a U-shaped cross section, and a pad retainer attachment portion 3f for attaching a pad retainer 12 is provided on the radially outer side of the pad guide groove 3e.

The friction pad 6 comprises a back plate 6a and a lining 6b that is attached to the disc rotor side of the back plate 6a. Ears 6c, 6c are protruding from both sides of the back plate 6a, and the ears 6c, 6c are supported by pad guide grooves 3e on the disc rotation side and the rotation side via pad retainers 12. The back plate 6a is formed in a roughly fan shape with a disc circumferential width dimension on the disc radially outer side longer than the disc circumferential width dimension on the disc brake radially inner side. On the disc rotor side of the back plate 6a on the disc rotation side, a thin engagement groove 6d that is elongated in the disc circumferential direction is formed, and the engagement groove 6d is formed in a V-shape with a depth that gradually deepens toward the center C1 of the engagement groove 6d. A shim plate 13 is attached to the opposite disc rotor side of the back plate 6a.

The pad return spring 7 is formed by bending an elongated member, for example, a wire rod, and includes a folded portion 7a that is folded back in an arc shape at the center of the wire rod and located on the outer periphery of the disk rotor 2 and at the midpoint of the pair of friction pads 6, 6, a pair of spring portions 7b, 7b that extend from both ends of the folded portion 7a toward the pair of friction pads 6, 6 in directions away from each other, and a pair of engaging portions 7c, 7c that extend further away from the pair of spring portions 7b, 7b and engage with the engaging grooves 6d, 6d, respectively. The pair of engaging portions 7c, 7c includes a pair of straight portions 7d, 7d that extend linearly from the pair of spring portions 7b, 7b in directions away from each other in the disk axial direction, and a pair of curved portions 7f, 7f that extend from the pair of straight portions 7d, 7d in a convex curve in the direction away from each other, with the tips 7e, 7e approaching each other.

The pad return spring 7 is attached to the friction pads 6, 6 by assembling the friction pads 6, 6 to the caliper bracket 3, and then orienting the pad return spring 7 so that the folded portion 7a faces the disk rotation side (the center side of the friction pad) and the pair of spring portions 7b, 7b faces the disk rotation side (the side of the friction pad), and pinching and pressing the pair of corners 7g, 7g formed between each spring portion 7b and the straight portion 7d, so that the pair of spring portions 7b, 7b and the pair of engagement portions 7c, 7c are brought close to each other. Next, the folded portion 7a is positioned on the outer periphery side of the disc rotor 2 and at the middle position of the disk rotation side of the pair of friction pads 6, 6, and further, the pair of curved portions 7f, 7f are positioned corresponding to the pair of engagement grooves 6d, 6d. Next, the pressure applied to the pair of spring portions 7b, 7b is released, and the curved portions 7f, 7f are engaged with the engagement grooves 6d, 6d, thereby assembling the pad return spring 7 to the friction pads 6, 6.

When the driver applies the brakes and pressurized hydraulic fluid is supplied to the hydraulic chamber 11 of the vehicle disc brake 1 thus formed, the piston 8 advances in the cylinder bore 5d, pressing the friction pad 6 on the acting portion 5a side toward the disc rotor 2. The friction pad 6 on the acting portion 5a side moves through the pad guide grooves 3e, 3e toward the disc rotor 2 while the ears 6c, 6c are guided by the pad retainers 12, 12, and the lining 6b slides against one side of the disc rotor 2. Next, the caliper body 5 moves toward the acting portion 5a while being guided by the slide pins 4, 4 due to this reaction force, and the reaction claw 5f provided on the reaction portion 5b side presses the friction pad 6 on the reaction portion 5b side toward the other side of the disc rotor 2. The friction pad 6 on the reaction portion 5b side moves through the pad guide grooves 3e, 3e toward the disk rotor 2 while the ears 6c, 6c are guided by the pad retainers 12, 12, and the lining 6b slides against the other side of the disk rotor 2. At this time, as the friction pads 6, 6 move toward the disk rotor 2, the folded portion 7a and the spring portions 7b, 7b of the pad return spring 7 elastically deform, and the spring portions 7b, 7b and the engagement portions 7c, 7c approach each other.

When the braking operation is released, the piston 8 rolls back due to the restoring force of the piston seal 9, and the piston 8 and reaction claw 5f retreat to the positions before braking began. The restoring force of the pad return spring 7 causes the spring portions 7b, 7b to return to their initial state in which they are separated from each other, centered on the folded portion 7a. As a result, the curved portions 7f, 7f press the engagement grooves 6d, 6d toward the opposite disc rotor side, moving both friction pads 6, 6 toward the opposite disc rotor side and preventing the friction pads 6, 6 from dragging.

As described above, in this embodiment, when assembling the pad return spring 7 to the friction pad 6, 6, the pair of spring portions 7b, 7b are pressed, the pair of engagement portions 7c, 7c are brought close to each other, and the pair of curved portions 7f, 7f are arranged in positions corresponding to the pair of engagement grooves 6d, 6d. Then, by releasing the pressure applied to the pair of spring portions 7b, 7b, the curved portions 7f, 7f engage with the engagement grooves 6d, 6d, and the pad return spring 7 can be easily assembled to the friction pad 6, 6.

Furthermore, by forming the pair of engagement parts 7c, 7c with straight parts 7d, 7d and curved parts 7f, 7f, when assembling the pad return spring 7 to the friction pad 6, 6, the pair of spring parts 7b, 7b can be easily pressed in a direction to approach each other by pinching the pair of corners 7g, 7g formed between each spring part 7b and the straight part 7d. Furthermore, by engaging the curved parts 7f, 7f with the engagement grooves 6d, 6d, the ease of assembly can be improved. In addition, the pair of engagement grooves 6d, 6d are formed in a V-shape with the depth of the groove gradually increasing toward the center part C1, which increases the contact area between the curved parts 7f, 7f and the engagement grooves 6d, 6d, and the pad return spring 7 can be reliably assembled to the friction pad 6, 6.

The present invention is not limited to the above-mentioned embodiment, and an engagement groove may be formed on the disc rotation side of the back plate of the friction pad, and a pad return spring may be arranged on the disc rotation side as well, or a pad return spring may be arranged only on the disc rotation side. Furthermore, the engagement groove is not limited to a V-shape in which the depth of the groove gradually deepens toward the center, and may be one in which the depth of the groove does not change. Furthermore, the engagement portion of the pad return spring is not limited to one having a straight portion and a curved portion, but may be one that extends from the spring portion in directions away from each other and engages with the engagement grooves. Furthermore, the pad return spring is not limited to one made of wire, and may be one made of a long, thin metal plate.

1...vehicle disc brake, 2...disc rotor, 3...caliper bracket, 3a...caliper support arm, 3b...vehicle body mounting portion, 3c...tie rod, 3d...guide hole, 3e...pad guide groove, 3f...pad retainer mounting portion, 4...slide pin, 4a...mounting bolt, 5...caliper body, 5a...action portion, 5b...reaction portion, 5c...bridge portion, 5d...cylinder hole, 5e...slide pin mounting arm, 5f...reaction claw, 6...friction pad, 6a...back plate, 6b...lining, 6c...ear, 6d...engagement groove, 7...pad return spring, 7a...folded portion, 7b...spring portion, 7c...engagement portion, 7d...straight portion, 7e...tip portion, 7f...curved portion, 7g...corner portion, 8...piston, 9...piston seal, 10...dust seal, 11...hydraulic chamber, 12...pad retainer, 13...shim plate

Claims (3)

A vehicle disc brake in which a pair of friction pads are arranged on both sides of a disc rotor and formed by attaching a lining to a back plate on the disc rotor side, and a pad return spring is attached to radially outer parts of the disc of the pair of friction pads for biasing the pair of friction pads toward the opposite disc rotor side,
The pair of friction pads are formed with a pair of engagement grooves, elongated in the disk circumferential direction, facing each other on the disk rotor side surface on the outer side of the disk radial direction of the back plate, for engaging the pad return spring,
The pad return spring is formed by folding an elongated member, and includes a folded portion that is folded back at the center of the elongated member and is positioned on the outer circumferential side of the disc rotor and at a midpoint between the pair of friction pads, a pair of spring portions that extend from both ends of the folded portion in directions away from each other toward the pair of friction pads, and a pair of engagement portions that extend further away from the pair of spring portions and each engage with the engagement groove. A vehicle disc brake as claimed in claim 1, characterized in that the pair of engagement grooves are formed in a V-shape with the depth of the groove gradually increasing towards the center. The vehicle disc brake according to claim 1 or 2, characterized in that the pair of engagement parts each include a pair of straight parts that extend linearly from the pair of spring parts in directions that move away from each other in the disk axial direction, and a pair of curved parts that extend from the pair of straight parts in a convex curve in the direction that moves away from each other, with their tips approaching each other, and the pair of curved parts each engage with the pair of engagement grooves.

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