JP2004270729A - Brake pad return structure for disc brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent drag of a brake pad, by surely and uniformly separating the brake pad from a disc rotor, in a disc brake. <P>SOLUTION: A pad shim 5 is disposed to a back metal 2b of the brake pad 2 arranged to face a braking face of the disc rotor 1, a central portion of the pad shim 5 is fixed to the back metal 2b by four claws 5a, and both end portions 5b of the pad shim 5 are elastic members elastically deformable in the stroke direction of the brake pad 2. Each elastic member 5b has a curved tip part 5c projecting in a rotating direction of the disc rotor of the brake pad 2, and the elastic members 5b are elastically brought into contact with a torque receiving part 3b. In a free form of the elastic members 5b including the curved tip parts 5c, the brake pad 2 is separated from the disc rotor 1. In braking where a piston 4 pushes the brake pad 2 against the disc rotor 1, the elastic members 5b are elastically deformed in a manner shown in δ by a brake pad pushing force F1, in which an elastic contact part to the torque receiving part 3b (curved tip parts 5c of the elastic member) functions as a point of support, and the brake pad 2 can be returned by the reaction force. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a brake pad returning structure for separating a brake pad from a disk rotor after a braking operation is completed in a disk brake for braking a disk rotor that rotates integrally with a wheel.
[0002]
[Prior art]
The disc brake strokes a brake pad arranged opposite to the braking surface of the disk rotor and presses the brake pad against the braking surface of the disk rotor so that the torque of the disk rotor is received by the torque receiving portion of the caliper via the brake pad. Constitute.
In the case of a disc brake, it is necessary to return the brake pad to a position separated from the disc rotor after the end of the braking operation for removing the pressing force that presses the brake pad against the braking surface of the disc rotor. As an invention related to the structure to be performed, conventionally, as described in Patent Document 1, for example, a pad spring is locked on a curved portion of a wear warning member attached to a brake pad, and after the braking operation is completed, the pad spring locks the brake pad. There is known a device in which a position before a braking operation is urged to separate from a disk rotor.
[0003]
[Patent Document 1]
JP-A-8-200409
[Problems to be solved by the invention]
However, the above-described conventional invention has the following problems.
That is, the layout of the pad spring is likely to be restricted by the shape of the wear warning member and the peripheral members, and it may be difficult to form the pad spring so as to obtain a sufficient urging force.
[0005]
The wear alarm member is usually provided at one or two places on the back pad of the brake pad. However, in most cases, the resultant force of the urging force of the pad springs provided in connection with the wear alarm member does not coincide with the center of gravity of the brake pad. In some cases, the brake pads are inclined so that the entirety cannot be evenly separated from the disk rotor.
Therefore, even after the end of the braking operation, a local drag between the brake pad and the disk rotor may occur.
[0006]
The present invention is designed so as not to be largely restricted by the layout, to obtain a sufficient brake pad return force with a simple structure, and to be able to relatively uniformly separate the entire brake pad from the disk rotor. It is an object of the present invention to propose a brake pad return structure in which the above problems are all solved.
[0007]
[Means for Solving the Problems]
For this purpose, the brake pad return structure of the disc brake according to the present invention is as described in claim 1.
By pressing a brake pad against a braking surface of a disk rotor, a disk brake configured to receive a rotational force of the disk rotor by a fixed torque receiving portion via a brake pad,
An elastic member that protrudes from the brake pad and elastically contacts the torque receiving portion is provided on the brake pad,
At the time of a stroke for pressing the brake pad against the disk rotor braking surface, the elastic member is elastically deformed with the elastic contact portion with the torque receiving portion as a fulcrum.
[0008]
【The invention's effect】
According to the configuration of the present invention, when the brake is stroked so as to press the brake pad against the disk rotor braking surface, the elastic member is elastically deformed in the stroke direction while being engaged with the torque receiving portion, so that the brake pad is subjected to the stroke. Allow braking.
On the other hand, at the time of non-braking, in which the brake pad pressing force against the disk rotor braking surface is released, the elastic member is free due to the elastic deformation reaction force, and the brake pad is dragged by returning the brake pad to its original position separated from the disk rotor. To prevent
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 and 2 show an opposed caliper type disc brake device for a vehicle having a brake pad return structure according to one embodiment of the present invention. FIG. 1 shows this disc brake from above a caliper opening 3a. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 and showing the brake pad 2 viewed in the direction of the arrow.
[0010]
A pair of brake pads 2 and 2 are arranged on the braking surfaces on both sides of the disk rotor 1 which rotates together with wheels not shown.
The brake pads 2, 2 are pressed against the braking surfaces on both sides of the disk rotor 1 by advancing strokes of the pistons 4, 4 slidably fitted in the caliper 3 in directions approaching each other.
At this time, the brake pads 2 and 2 try to rotate together with the disk rotor 1 due to frictional contact with the disk rotor 1, and this rotation is caused by the brake pads (2, 2) formed on the torque receiving portion 3 b of the caliper 3. 2), that is, the torque of the disk rotor 1 is received by the fixed torque receiving portion 3b via the brake pads 2 and 2, so that a required braking action can be obtained. .
[0011]
Each of the brake pads 2 has a similar configuration in a shape elongated in the direction of rotation of the disk rotor, and a pad body 2a on the side near the disk rotor 1 and a back metal 2b on the side near the piston 4 are bonded to each other.
A back shim 2b of the brake pad 2 is provided with an elastically deformable pad shim 5 having substantially the same shape (rectangular shape) along a plane close to the piston 4 and preferably made of metal such as stainless steel or spring steel. The board is composed as follows.
[0012]
A relatively wide central portion of the pad shim 5 is fixed to the back pad 2b of the brake pad 2 by holding the back metal 2b with four claws 5a, and both ends 5b, 5b outside the central portion are braked by the piston 4. The pad 2 is configured as a member that can be elastically deformed in the stroke direction.
These elastic members 5b set at both ends of the pad shim 5 have front ends 5c protruding from both ends of the brake pad 2 in the disk rotor rotation direction, and these elastic member front ends 5c are preferably located at the center of gravity G of the brake pad 2. At the position (see FIG. 2), it is disposed at a position opposite to the lateral direction α (hereinafter referred to as α direction) crossing the brake pad stroke direction.
[0013]
As shown in FIG. 1, the elastic member tip portions 5c projecting from both ends of the brake pad 2 in the disk rotor rotation direction are curved so as to have irregularities in the brake pad stroke direction, and formed on the pad backing metal 2b as shown in FIG. Is located in the cutout 2c.
The curved distal end portion 5c is elastically contacted with the torque receiving portion 3b while being contracted toward the center portion of the pad shim, whereby the elastic member curved distal end portion 5c is elastically contacted with the torque receiving portion 3b.
It is to be noted that elastic contact can be similarly performed by using an engaging member as shown in FIGS. 7, 8, and 11 instead of the distal end portion 5c.
[0014]
The engaging member 7 shown in FIG. 7 is formed so as to protrude from the tip of the elastic member 5b toward the torque receiving portion 3b. The engaging member 7 has a curved portion 7a which is curved in the radial direction of the disk rotor 1 at the center thereof, and in the caliper 3, the distal end portion 7b of the engaging member 7 undergoes pressure deformation from the torque receiving portion 3b. As a result, the distal end of the elastic member 5b elastically contacts and locks with the torque receiving portion 3b.
[0015]
The engaging member 8 shown in FIG. 8 is formed of an elastic material such as rubber, and has a thickness in the α direction so as to protrude from the distal end of the elastic member 5b toward the torque receiving portion 3b in a free shape, and has a brake. An appropriate thickness is secured in the stroke direction of the pad 2 (hereinafter referred to as the stroke direction), and the pad 2 is provided at the opposite electrode positions at both ends of the pad shim 5. In the caliper 3, the distal end of the elastic member 5b elastically contacts and locks with the torque receiving portion 3b because the thick portion in the α direction receives the pressing deformation from the torque receiving portion 3b.
[0016]
The engaging member 11 shown in FIG. 11 has a helical spring shape, and is provided at opposite ends of both ends of the pad shim 5 so as to protrude from the distal end of the elastic member 5b toward the torque receiving portion 3b in the free shape. When the helical spring 11 is compressed, the spring diameter is appropriately selected so as not to buckle. In the caliper 3, the tip of the elastic member 5b elastically contacts and engages with the torque receiving portion 3b when the helical spring 11 receives the pressing deformation in the spring length direction from the torque receiving portion 3b.
[0017]
The free shape of the elastic member 5b including the curved tip portion 5c is a free shape such that the brake pad 2 is separated from the disk rotor 1 with a predetermined pad gap β in the free state shown in FIG.
[0018]
In this embodiment having the above-described configuration, when the brake pad 2 is pressed against the braking surfaces on both sides of the disk rotor 1 by the advance stroke of the piston 4, the brake pad pressing force F1 as shown in FIG. The elastic member 5b set in the portion is elastically deformed by an amount of bending indicated by δ in FIG. 3 with the elastic member curved tip portion 5c serving as a locking position at which the elastic member 5b elastically contacts the torque receiving portion 3b as a fulcrum.
[0019]
When the pressing force F1 of the brake pad 2 by the piston 4 is removed, as shown in FIG. 4, the elastic member 5b returns to the free state shown in the drawing by the elastic deformation reaction force F2 generated by the elastic deformation. 2 is separated from the braking surfaces on both sides of the disk rotor 1, and a predetermined pad gap β shown in FIG.
[0020]
By the way, since the returning operation of the brake pad 2 is caused by the elastic member 5b provided on the brake pad 2 at the opposite position in the transverse direction crossing the stroke direction of the brake pad 2,
The return force acting on the brake pad 2 can be made uniform as a whole, and the brake pad 2 can be returned in a state of being relatively uniformly separated from the disk rotor 1, so that the local area of the brake pad 2 can be reduced. Dragging can be avoided.
As described above with reference to FIG. 2, when the elastic member distal end portion 5c is disposed at the opposite position in the lateral direction α crossing the brake pad stroke direction at the position of the center of gravity G of the brake pad 2, the return force acting on the brake pad 2 is more uniform. Thus, the above-mentioned effects are more remarkable.
[0021]
Further, the elastic member 5b for returning the brake pad 2 is projected from the brake pad 2 in the lateral (α) direction to the torque receiving portion 3b and is brought into elastic contact therewith.
The elastic member 5b is not much affected by layout restrictions, and a sufficient brake pad return force can be generated with a simple structure, and these layout restrictions and problems relating to the brake pad return force can be solved. be able to.
[0022]
Further, since the distal end portion 5c of the elastic member 5b elastically contacting the torque receiving portion 3b is curved so as to have irregularities in the brake pad stroke direction,
Even if there is a dimensional variation in the opposing interval between the torque receiving portions 3b, this can be absorbed by the deformation of the elastic member curved distal end portion 5c, and there is an advantage that special dimensional management is not required.
It should be noted that the same effect can be obtained with the engaging members 7, 8, and 11 in addition to the above-described distal end portion 5c.
[0023]
Further, in the present embodiment, when the elastic member 5b is provided on the brake pad 2, a pad shim 5 that can be elastically deformed is provided along the back metal 2b of the brake pad 2, and a relatively wide central portion of the pad shim 5 is attached to the brake pad 2. The back metal 2b is fixed to the back metal 2b with four claws 5a, and both ends outside the center are formed as elastic members 5b.
The elastic member 5b can be provided relatively easily with respect to the brake pad 2, and the spring effective length L shown in FIG. 3 can be lengthened despite space restrictions, and the shim shown in FIG. It is easy to set the brake pad return force in relation to the plate thickness t and the shim width b shown in FIG. 2, and in addition, the installation strength of the elastic member 5b with respect to the brake pad 2 and the strength of the elastic member 5b itself increase. Durability can be improved.
[0024]
Even if the engaging members 7, 8, and 11 are used instead of the elastic member distal end portion 5c, the elastic member 5b naturally has the same effect as shown in FIGS.
[0025]
The effect of the installation strength of the elastic member 5b and the effect of the strength of the elastic member 5b itself becomes more remarkable when the pad shim 5 is made of a metal plate such as stainless steel or spring steel. The required heat resistance in a certain environment can be ensured, and the brake pad return force can be increased.
[0026]
Here, considering the elastic deformation reaction force F2 of the elastic member 5b set at both ends of the pad shim 5, the Young's modulus of the elastic member 5b is determined from the relationship between the amount of bending and the load in the elastic deformation of the cantilever. If E
F2 = (2δ · E · b · t ³ ) / 4L ³
Is represented by
Therefore, the specifications of the elastic member 5b are determined such that the elastic deformation reaction force F2 obtained from the above equation from the amount of deflection δ of the elastic member 5b during braking is larger than the sliding resistance required to return the brake pad 2. When the pad shim 5 is formed by the above, the above-described brake pad returning action can be achieved.
[0027]
For example, since the sliding resistance required to return the brake pad 2 is about 3 kgf, the amount of deflection δ of the elastic member 5b during braking is 0.5 mm, and the thickness of the pad shim 5 is t = 0. When stainless steel of .4 mm is used, the spring effective length L is set to 17 mm and the shim width b is set to 50 mm so that an elastic deformation reaction force F2 of 3.42 kgf can be obtained. 2 can be returned away from the disk rotor 1.
[0028]
If the required elastic deformation reaction force F2 cannot be obtained due to a large sliding resistance required to return the brake pad 2 or a limitation on the dimensions of the pad shim 5, as shown in FIG. For example, a U-shaped ridge 5d projecting in a direction away from the pad backing metal 2b is formed in the elastic member (5b) setting region at both end portions of the elastic member 5b, thereby increasing the spring constant of the elastic member 5b to increase the elastic member 5b. Can be increased.
[0029]
Conversely, when the elastic deformation reaction force F2 becomes excessively small, it is not shown in the drawing. However, for example, a U-shaped slit-shaped groove is formed in the elastic member (5b) setting region at both ends of the pad shim 5. Is formed, whereby the spring constant of the elastic member 5b can be reduced and the elastic deformation reaction force F2 of the elastic member 5b can be reduced.
[0030]
In addition, as shown in FIG. 12, by providing two wide claws 5aa at the center of the long side of the pad shim 5 instead of the four claws 5a, the spring effective length and the pad gap β can be increased, The characteristics of the elastic member 5b can be changed according to the layout of the caliper 2 such as reducing the deformation reaction force F2.
[0031]
To increase the elastic deformation reaction force F2 of the elastic member 5b, in addition to the countermeasure shown in FIG. 5, a countermeasure by combining a plurality of pad shims 5 as shown in FIG. 6 is also possible.
That is, an additional pad shim 6 that is elastically deformable is provided on the side of the pad shim 5 far from the brake pad 2.
[0032]
Such an additional pad shim 6 has substantially the same shape (rectangular shape) as the plane of the pad shim 5 and has a size that covers the central portion and the effective spring length L, but does not cover the elastic member curved tip 5c, and is preferably made of stainless steel. And made of metal plate such as spring steel.
Such an additional pad shim 6 is also fixed to a relatively wide central portion by holding the back metal 2b of the brake pad 2 with four claws 6a.
Thus, the additional pad shim 6 can cover the elastic member 5b to increase its spring constant and increase the elastic deformation reaction force F2 during braking of the elastic member 5b.
[0033]
In the embodiment described above, the brake pad 2 is separated from the braking surface of the disk rotor 1 by using the elastic deformation reaction force F2 of the elastic member 5b. This operation is performed by the brake pad 2 and the torque receiving portion 3b. It is also possible to concentrate on the engaging portion with the above, or to share the function of the engaging portion and the elastic member 5b.
For example, when the pad shim 5 shown in FIGS. 8 and 11 is a rigid body, or when the claw 5a is provided near the torque receiving portion 3b and the spring effective length L of both ends 5b of the pad shim is omitted, both ends of the pad shim 5 Although the above function as an elastic member cannot be achieved, the thickness of the engaging member 8 in the stroke direction and the α direction is appropriately selected, and the elastic characteristic of the engaging member 8 is appropriately changed, so that it is possible to achieve the effect of braking. As shown in FIG. 10, the engaging member 8 receives the pressing force F1 from the piston 4, and is elastically deformed in the stroke direction while elastically contacting the torque receiving portion 3b.
[0034]
Then, when the pressing force F1 of the brake pad 2 by the piston 4 is removed, the engaging member 8 recovers to the original elastic contact shape, thereby separating the brake pad 2 from the braking surfaces on both sides of the disk rotor 1.
[0035]
Further, even when the helical spring 11 is used as the engaging portion, the spring length and the spring diameter are appropriately selected, and the spring coefficient is appropriately changed so that the helical spring 11 as shown in FIG. The spring 11 receives the pressing force F1 from the piston 4 and elastically deforms in the stroke direction while being elastically in contact with the torque receiving portion 3b.
[0036]
Then, when the pressing force F1 of the brake pad 2 by the piston 4 is removed, the engagement member 11 is restored to the original elastic contact shape, thereby separating the brake pad 2 from the braking surfaces on both sides of the disk rotor 1.
[0037]
Next, in another embodiment of the present invention, the engaging member 14 shown in FIG. 14 is formed so as to protrude from the center of both side edges of the pad shim 15 in the α direction. The engaging member 14 has a curved portion 14a which is curved at the center thereof so as to be on the side opposite to the position of the disk rotor 1 in the stroke direction. It is suitable. In addition, a C-shaped hook 14c for connecting the brake pad 2 is provided at the base of the engaging member 14. On the other hand, protrusions 2c that can be fitted with the hooks 14c are provided at both ends of the brake pad back metal 2b on the torque receiving portion 3b side.
An engagement groove 3e is provided on a surface 3d of the torque receiving portion 3b parallel to the disk rotor 1. In the caliper 3, the tip end 14b of the engagement member 14 is locked in the engagement groove 3e. As shown, the protrusion 2c is fitted to the protrusion 13c, so that the brake pad 2 is supported by the torque receiving portion 3b.
[0038]
At the time of braking, the pad shim 15 receives a pressing force from the piston 4, and the pressing force acts on the engaging member 14, and the engaging member 14 is elastic in the stroke direction with its tip 14 b elastically contacting the engaging groove 3 e. The brake pad 2 which is deformed and locked by the base 14c is displaced in the stroke direction.
[0039]
When the pressing force from the piston 4 is removed, the engaging member 14 returns to the original elastic contact position, whereby the brake pad 2 can be separated from the braking surface of the disk rotor 1.
[Brief description of the drawings]
FIG. 1 is a plan view of a main part of an opposed caliper type disc brake device provided with a brake pad return structure according to an embodiment of the present invention, as viewed from above a caliper opening.
FIG. 2 is a sectional view taken along line II-II of FIG. 1 and showing the brake pad viewed in the direction of the arrow.
FIG. 3 is an operation explanatory view showing an operation state of the brake pad return structure according to the embodiment during braking.
FIG. 4 is an operation explanatory view showing a brake pad return operation of the brake pad return structure according to the embodiment during non-braking.
FIG. 5 is a perspective view of a pad shim used in a brake pad return structure according to a second embodiment of the present invention.
FIG. 6 is a side view of a brake pad used in a brake pad return structure according to a third embodiment of the present invention.
FIG. 7 is a perspective view of a pad shim used in a brake pad return structure according to a fourth embodiment of the present invention.
FIG. 8 is a perspective view of a pad shim used in a brake pad return structure according to a fifth embodiment of the present invention.
9 is a side view showing a state in which the pad shim used in the brake pad return structure shown in FIG. 8 is elastically deformed during braking.
FIG. 10 is a side view showing a state in which the pad shim used in the brake pad return structure shown in FIG. 8 does not elastically deform during braking, and only the engagement portion with the torque receiving portion is elastically deformed.
FIG. 11 is a perspective view of a pad shim used in a brake pad return structure according to a sixth embodiment of the present invention.
12 is a side view showing a state in which the pad shim used in the brake pad return structure shown in FIG. 11 is elastically deformed during braking.
13 is a side view showing a state in which a pad shim used in the brake pad return structure shown in FIG. 11 does not elastically deform during braking, and only an engagement portion with a torque receiving portion is elastically deformed.
FIG. 14 is a perspective view showing a state in which a pad shim used in a brake pad return structure according to a seventh embodiment of the present invention is engaged with a torque receiving portion.
15 is a partial perspective view showing a state in which a brake pad back metal is locked with a pad shim used in the brake pad return structure shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Disc rotor 2 Brake pad 2a Pad body 2b Back metal 3 Caliper 4 Piston 5 Pad shim 6 Pad shim 7, 8, 11, 14 Engaging member

Claims (11)

By pressing a brake pad against a braking surface of a disk rotor, a disk brake configured to receive a rotational force of the disk rotor by a fixed torque receiving portion via a brake pad,
An elastic member that protrudes from the brake pad and elastically contacts the torque receiving portion is provided on the brake pad,
A brake pad return structure for a disc brake, wherein the elastic member is elastically deformed with a fulcrum at an elastic contact portion with the torque receiving portion during a stroke of pressing the brake pad against the disc rotor braking surface. 2. The disk according to claim 1, wherein the elastic members are provided as a set of two elastic members, and the elastic members are arranged at opposite positions in a transverse direction transverse to a stroke direction of the brake pad. Brake pad return structure for the brake. 3. The brake pad return structure for a disc brake according to claim 2, wherein the lateral direction is a direction transverse to a stroke direction of the brake pad at a position of a center of gravity of the brake pad. 4. The disk according to claim 1, wherein a pad shim that is elastically deformable is provided along a back metal of the brake pad, and the pad shim constitutes the elastic member. Brake pad return structure for the brake. 5. The brake pad return structure according to claim 4, wherein an elastic contact portion of the pad shim elastically contacting the torque receiving portion is elastically deformable in a lateral direction transverse to a stroke direction of the brake pad, and the elastic deformation allows the elastic member to move in the lateral direction. A brake pad return structure for a disc brake, characterized in that it is configured to absorb dimensional variations of parts in the above. 6. The brake pad return structure for a disc brake according to claim 5, wherein said pad shim is made of a metal plate. The brake pad return structure according to any one of claims 4 to 6, wherein the pad shim is provided with a ridge for increasing an elastic deformation reaction force generated during a stroke of the brake pad. Brake pad return structure for disc brakes. The brake pad return structure according to any one of claims 4 to 6, wherein the pad shim is provided with a groove for reducing an elastic deformation reaction force generated at the time of stroke of the brake pad. Brake pad return structure for disc brakes. 7. The brake pad return structure according to claim 4, wherein an additional pad shim that is elastically deformable is provided so as to overlap the pad shim, so that an elastic deformation reaction force of the pad shim generated during a stroke of the brake pad is provided. 8. The brake pad return structure of the disc brake, characterized by a larger size. 4. The brake pad return structure according to claim 1, wherein a pad shim that is not elastically deformable is provided along a back metal of the brake pad, and the elastic member is provided between the pad shim and the torque receiving portion. 5. The brake pad return structure of the disc brake, which is interposed. 11. The brake pad return structure according to claim 10, wherein the elastic member interposed between the elastically non-deformable pad shim and the torque receiving portion is also elastically deformable in a transverse direction transverse to a stroke direction of the brake pad. A brake pad return structure for a disc brake, characterized in that the elastic deformation can absorb dimensional variations of components in the lateral direction.

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