JPH06280909A - Disc brake device - Google Patents

Abstract

PURPOSE:To amplify brake force by a simple constitution and prevent the eccentric wear of a friction pad. CONSTITUTION:In a disc brake device, a bell crank 10 for generating a pad push-pressure in a roter shaft direction by a lever operation after receiving force in the roter circumferential direction of friction pads, 3,4 caused by brake force is interposed between the pads 3,4 and brake force receivers 2c-2f.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake device for amplifying a braking force and preventing uneven wear of a friction pad.

[0002]

2. Description of the Related Art As a disc brake device for increasing the braking force, it is disclosed in JP-A-55-60737. This device is a disc brake device in which a pair of friction pads are pressed against both sides of a braking disc by a cylinder device in a direction perpendicular to the braking disc. A caliper formed of an annular plate that is slidable on the braking disc and straddles the braking disc; and an annular friction pad supporting member that is fixedly supported by the fixing member, and is parallel to the braking disc of the supporting member. A pair of notches are provided in the pair of inner edge portions at intervals in the circumferential direction of the braking disc, and the base ends of the pair of links whose tips are abutted by the return springs are provided in the notches. The back plate of the pad is supported at each end by a pin extending parallel to the side surface of the braking disc and extending at a right angle to the pressing direction of the friction pad.

[0003]

Problems to be Solved by the Invention The above-mentioned conventional disc brake device has the following problems.

Since the wear pad moves toward the braking disc as the friction material wears, the angle formed by each pair of links decreases. The servo effect boost factor is determined by this angle, and wear will increase the boost factor.
Accordingly, the servo effect fluctuates due to pad wear, and the braking effectiveness becomes unstable. Also, when the angle formed by each pair of links is reduced, the distance for the links to abut the notches in the support member increases, so that the movement of the braking disc in the circumferential direction of the pad during braking increases and the braking effect increases. There will be a delay.

When hydraulic pressure is supplied to the cylinder, each pad moves toward the braking disc, and when both pads are pressed against the braking disc, each pad continues the dragging motion until the link abuts the supporting member. To be Therefore, the amount of movement of the friction pad increases as the friction material wears, and as a result, the piston is twisted and the sliding resistance of the pad increases, resulting in severe wear of the pressing surface.

In addition to the components of a general disc brake device such as a pair of friction pads and calipers, the friction pad support member, the return spring, the link, the pin, and the like are large in number of additional parts, and the structure is complicated. Assembly workability is also complicated.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a disc brake device capable of increasing the braking force and preventing uneven wear of a friction pad. is there.

[0008]

That is, according to the present invention, a pair of braking force receiving portions that are spaced from each other in the rotation direction of the rotor and are parallel to the axis of the rotor are formed on a support member that is mounted on the vehicle body at one side of the rotor. A disc brake device in which at least one of a pair of friction pads frictionally engaged with both side surfaces of the rotor is mounted between the braking force receiving portions, and the braking force of the pads during braking is supported by the braking force receiving portions. In the above, a bell crank that receives the force of the pad in the rotor circumferential direction due to the braking force and generates a pad pressing force in the rotor axial direction by the lever action is interposed between the pad and the braking force receiving portion. It is a characteristic disc brake device.

[0009]

Embodiment 1 Next, an embodiment of the present invention will be described with reference to the drawings.

<B> Overall configuration FIG. 1 is a plan view of a disc brake device with a part cut away,
FIG. 2 shows a partially cutaway front view thereof. The rotor 1 is fixed to the axle, and the carrier 2 which is a supporting member has a mounting hole 2
It is attached to the vehicle body via bolts a and 2b.
A plurality of braking force receiving portions 2c to 2f are formed on the carrier 2, and the pair of braking force receiving portions 2c and 2d are formed on the inner pad 3.
Slidably supporting the other pair of braking force receiving portions 2e, 2f
Supports the outer pad 4 slidably. The braking force receiving portions 2c and 2e and 2d and 2f may be formed continuously and integrally. The caliper 5 is supported by a pair of guide pins 6 and 7 embedded in the carrier 2 so as to be slidable in the axial direction of the rotor 1. A piston 8 is liquid-tightly inserted in a cylinder hole 5a formed in one side of the caliper 5, and an action pawl 5b is formed in the other side across the rotor 1 so as to be opposed to both side surfaces of the rotor 1. The inner pad 3 and the outer pad 4 are arranged facing each other.

<B> Bell crank A total of four bell cranks 10 are interposed between the pads 3 and 4 and the braking force receiving portions 2c to 2f. Since all of the bell cranks 10 are the same, the part interposed between the outer pad 4 and the braking force receiving portion 2e will be described with reference to FIGS. 3 and 4, and the description of the bell crank 10 in other parts will be omitted. The bell crank 10 is a steel lever member having a substantially L shape, and is a side surface 4b of the back metal 4a of the outer pad 4.
The first engaging portion 10a abutting against the back metal 4a, the pressing portion 10b abutting against the back surface 4c of the backing metal 4a, and the first engaging portion 10a away from the rotor 1 in the axial direction of the rotor 1 (y dimension in FIG. 3). The second engagement portion 10c, which comes into contact with the braking force receiving portion 2e at the position and serves as the center of rotation, is integrally formed. The bell crank 10 may be formed into a columnar shape by a known drawing process or extrusion process, cut into a predetermined size, or molded by press working or forging, or a sintered material. The bell crank 10 is elastically held on the outer pad 4 by a clip 11. The clip 11 is formed by bending a spring plate into a crank shape, and has an abutting portion 11a that abuts against the pressing portion 10b of the bell crank 10, a bottom portion 11b formed on the other end side of the abutting portion 11a, and both surfaces 11a and 11b. A pair of sandwiching pieces 11 which are formed by bending both side edges of the contact portion 11a and the intermediate portion 11c that connects the intermediate portion 11c to the bottoming portion 11b.
It is configured by integrally molding d and 11d. Clip 11
Is a projection 4 having the bottom 11b formed on the back surface 4c of the backing metal 4a.
It is attached by crimping to d or using a bolt or the like.

[0013]

Next, the operation of the disc brake device will be described.

<A> During braking When the brake is operated during forward movement, the piston 8 moves downward in FIG. 1 to press the inner pad 3 against the rotor 1, and the reaction thereof presses the outer pad 4 against the other side surface of the rotor 1. The braking force is generated.

<B> Amplification of Brake Force When the rotation of the rotor in the direction of arrow Z in FIGS. Is the braking force receiving portion 2c, 2 on the left side of the drawing.
supported by e. When each of the pads 3 and 4 receives a rotational force in the Z direction, the lever pressing action of the bell crank 10 additionally generates a pad pressing force in the axial direction of the rotor 1 to amplify the braking force (self-servo effect). Figure 3 shows the outer pad 4
The bell crank 10 interposed between the brake force receiving portion 2e and the braking force receiving portion 2e is shown, and the mechanism for amplifying the braking force will be described with reference to FIG. In FIG. 3, the first engaging portion 10 a of the bell crank 10
The contact portion of the back metal 4a with the side surface 4b is P ₁ , the contact portion of the pressing portion 10b of the bell crank 10 with the back surface 4c is P ₂ , and the second engaging portion 10c of the bell crank 10 and the braking force receiving portion 2e. When the contact portion is P ₃ , when a force in the Z direction acts on the outer pad 4, this force is transmitted to the bell crank 10 via the contact portion P ₁ which is the point of force. Then, the bell crank 10 rotates counterclockwise around the contact portion P ₃ as a fulcrum, and as a result, the pressing portion 10 b of the bell crank 10 is pushed by the back surface 4 of the outer pad 4.
By pressing c, pad pressing force is generated in the rotor 1 axis direction. The above-described mechanism for amplifying the braking force is the same in the case of the bell crank 10 interposed between the inner pad 3 and the braking force receiving portion 2c, and when the rotor 1 is rotating in the direction opposite to the Z direction (reverse movement). The same function will be applied when braking is applied. The inner pad 3 receives the braking force by the braking force receiving portion 2d and the outer pad 4 receives the braking force by the braking force receiving portion 2f when the vehicle travels in the reverse direction of the arrow Z. Further, each bell crank 10 is attached to the pads 3 and 4 via the clip 11,
Therefore, since the bell crank 10 moves integrally with the pads 3 and 4 toward the rotor 1 as the friction material of the pads 3 and 4 wears, the fluctuation of the braking force amplifying mechanism and the delay of the braking effect described above occur. It can be avoided.

<C> Boosting Ratio of Servo Effect Next, the boosting ratio of servo effect by the bell crank 10 will be considered. In FIG. 3, the distance in the circumferential direction of the rotor 1 from the contact portion P ₃ that is the center of rotation of the bell crank 10 to the contact portion P ₂ that is the point of action is x, and the contact point P ₁ that is the force point makes contact. When the distance to the portion P _{3 in the} axial direction of the rotor 1 is y, the friction coefficient between the pads 3 and 4 and the rotor 1 is μ, and the pad pressing force in the axial direction of the rotor is F, the boost ratio is expressed by the following formula 1. be able to. (However, the frictional resistance of each part is not considered)

[Mathematical formula-see original document] That is, μ · y / x is the amplification amount of the servo effect. Therefore, the servo effect boost ratio is bell crank 1
It can be arbitrarily changed by the dimension ratio (y / x) of 0.

<D> Uneven Wear of Pads Next, uneven wear of the pads 3 and 4 will be examined. Generally, the pads that frictionally engage with both side surfaces of the rotating rotor are worn more on the rotor entry side than on the rotor entry side. So-called uneven wear occurs. This is because the action of biting into the rotor works on the rotor entry side of the pad, causing uneven surface pressure on the pad (high rotor surface pressure on the pad entry side and low rotor surface pressure on the entry side). is there. As a phenomenon, the pad turn-in side is close to the rotor and the turn-out side is tilted in a direction far from the rotor. In the present embodiment, the bell cranks 10 and 10 are respectively interposed between the pads 3 and 4 on the feeding side of the rotor 1 and the braking force receiving portions 2c and 2e, and the back surfaces of the pads 3 and 4 on the feeding side of the rotor are pressed. Since the inclinations of the pads 3 and 4 are corrected, uneven wear of the pads 3 and 4 as in the conventional case can be prevented.

[0018]

[Embodiment 2] Although the embodiment has been described as an embodiment applied to a pin slide type disc brake device using a carrier as a supporting member, it can also be applied to a fixed caliper type (so-called opposed type) disc brake device. Is. When applied to the fixed caliper type, the bell crank may be interposed between the braking force receiving portion formed on the caliper and the pad. In addition, the present invention can be applied to various types of disc brake devices, and in short, a bell crank may be interposed between the braking force receiving portion of the member that supports the braking force and at least one of the pair of pads.

[0019]

Third Embodiment As described above, the servo effect boosting ratio is determined by the dimensional ratio (y / x) of the bell crank 10. The dimensional ratio (y / x) is used as the braking force receiving portions 2c to 2f. And the friction coefficient of the contact surface between the bell crank 10 and the second engaging portion 10c of the bell crank 10, the second engaging portion 10c of the bell crank 10 does not roll on the braking force receiving portions 2c to 2f and slips. Occurs. However, if at least one of the contact surfaces of the braking force receiving portions 2c to 2f and the second engaging portion 10c of the bell crank 10 is subjected to a high friction coefficient process, the boosting ratio can be set to a larger value. This high coefficient of friction treatment includes, for example, performing shot blasting to create irregularities on the surface of the contact surface, coating anti-slip paint or synthetic resin material with a high coefficient of friction, and spraying ceramics, metal, etc. Can be adopted.

[0020]

Since the present invention is as described above, the following effects can be obtained.

<B> By the lever action of the bell crank interposed between the pad and the braking force receiving portion, the braking force can be amplified and the inclination of the pad during braking can be corrected to prevent uneven wear of the pad. It can be effectively prevented. .

<B> The servo effect boosting ratio can be arbitrarily set only by changing the dimension ratio of the bell crank, and the optimum boosting ratio according to the vehicle type can be easily obtained.

<C> Since the bell crank moves integrally with the pad toward the rotor even if the friction material is worn, there is no fluctuation in the servo magnification or delay in the braking effect, and a stable braking effect is always obtained. To be

<D> Since the bell crank has a simple shape, it is excellent in manufacturability and economically manufactured by adopting known forming methods such as drawing, extruding, pressing, forging, and sintering. it can. In a mass-produced product such as a disc brake device, in which the manufacturing cost of one part greatly affects the cost of the final product, the economical effect is extremely large.

<E> Since the bell crank is merely interposed between the pad and the braking force receiving portion, the structure is simple and the disc brake device can be easily assembled.

<F> It can be applied to various types of disc brake devices and is highly versatile.

[Brief description of drawings]

FIG. 1 is a plan view of a partially broken disc brake device.

FIG. 2 is a front view of a partially broken disc brake device.

FIG. 3 is an enlarged view of the bell crank at the outer pad end.

FIG. 4 is a perspective view of a bell crank and a clip.

[Formula 1]

Claims (2)

[Claims] 1. A pair of braking force receiving portions, which are spaced from each other in the rotational direction of the rotor and are parallel to the axis of the rotor, are formed on a support member attached to the vehicle body on one side of the rotor, and frictionally engage with both side surfaces of the rotor. In a disc brake device, in which at least one of a pair of friction pads is mounted between the braking force receiving portions and the braking force of the pads during braking is supported by the braking force receiving portions. Receiving directional force,
A disc brake device characterized in that a bell crank for generating pad pressing force in the rotor axial direction by leverage is interposed between the pad and the braking force receiving portion. 2. The bell crank has a first engaging portion that abuts a side surface of the pad, a pressing portion that abuts a back surface of the pad, and the bell crank at a position separated from the rotor in the rotor axial direction by the first engaging portion. A second member that comes into contact with the braking force receiving portion and becomes the center of rotation
The disc brake device according to claim 1, wherein the disc brake device comprises an engagement portion.