JP2510665Y2 - Disc brake - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a service type disc brake mainly used for passenger cars.

[0002]

2. Description of the Related Art Service-type disc brakes employ a seal retraction system utilizing elastic deformation of a piston seal in order to eliminate drag of a friction pad (hereinafter simply referred to as a pad) due to a disc (disc rotor) during non-braking. In many cases, when the brake is released, the brake piston is returned from the braking position by a certain amount. However, even if the piston is pulled back, the pad tries to remain in the braking position, so that the drag problem cannot be completely solved. Therefore, as shown in FIG. 5 and FIG. 6, a return spring 4 made by bending a spring wire rod is mounted between the pads 2 and 3 arranged to face each other with the disc D in between, and the pad force is applied by the spring force. Is being forced away from the disk.

The spring 4 has the foot portions 4a at both ends on the outer peripheral surface of the pad back plate (the surface facing the groove bottom of the disk groove 1a).
It is locked in the hole provided in the pad and push-back force is applied to the pad at this position.

[0004]

As shown in FIG. 6, the pad slide portion of the torque member 5 is usually provided with a retainer 6 for preventing rusting. In this case, at the same time, in order to eliminate rattle noise and crawl noise caused by the rattling of the pad, the retainer 6 is provided with a pad pressing portion 6a to press the pad outward from the disk center side.

In such a case, the pad is slid at two points in FIG. 6 (point b (point of restraint of movement of the pad by the torque member 5 outward in the radial direction of the disk)) and point c (point of pad pressure by the pressure portion 6a). Although a dynamic resistance is added, conventionally, the pad pressing point by the return spring 4 is provided at a position deviated from between the two points b and c, so that the return force is transmitted to the point c where the distance from the point a is large. It is difficult to do so, so that the return of the inner circumference of the pad is insufficient and dragging is still occurring.

It should be noted that if the spring force of the return spring 4 is increased so that a sufficient return force acts on the point c, drag can be eliminated. However, this method promotes piston knockback during traveling on a rough road, and It is not preferable because the stroke is extended.

[0007]

SUMMARY OF THE INVENTION In order to eliminate the drag of the pad without increasing the spring force of the spring 4, this invention is a disc brake using the above-mentioned retainer and return spring, and pressurizes the pad by the return spring. The points are provided in a region sandwiched between the movement restraint point of the pad by the torque member outward in the disk radial direction and the pad pressing point by the retainer.

[0008]

The force F ₀ is pressed against the disk tilts [action] is pad during non braking fulcrum point c in FIG. 6, of the force applied to the pad, f ₁ the sliding resistance acting on the point b in FIG. _6, point c When the sliding resistance f ₂ that acts on and the force of the return spring are F, the comparison is as follows in FIG.

FIG. 7A shows a conventional case in which the pad pressing point (point a) is located outside b and c, and FIG. 7B shows the case of the present invention in which point a is located between points b and c. , L ₃ is 5 cm in the past, 2 cm in the present invention, and other numerical values are both l ₁ = 1 cm, l ₂ = 3
It is assumed that cm and f ₁ = 1 kgf.

In the case of the conventional structure, when the force balance equation F ₀ a · l ₁ = F · l ₃ −f ₁ · l ₂ is applied to the numerical value above l ₃ = 5, F ₀ a = 5F-3, On the other hand, in the present invention, when the numerical value above l ₃ = 2 is applied to the formula of F ₀ b · l ₁ = F · l ₃ −f ₁ · l ₂ , F ₀ b = 2F−
3, therefore, when F = 3, F ₀ a = 12 kgf and F ₀ b = 3 kgf, and the drag force is reduced to 1/4 in this case.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view seen from the disk side with the caliper (1 in FIGS. 5 and 6) removed from the disk brake of the embodiment, FIG. 2 is its top view, and FIG. 3 is a side view. is there. The torque member is also omitted in FIGS. 2 and 3.

As shown in the figure, in the present invention, the pressing point (point a) of the pads 2, 3 by the return spring 4 is provided in the area sandwiched between the points b and c.

To press the pad by the spring 4, foot portions 4a bent in the disc axial direction are provided at both ends of the spring 4, and the foot portions are inserted into locking holes 7 provided in the back plate of the pad from the front surface of the back plate. The spring 4 can be easily attached and detached by inserting it, but the present invention is not limited to this.

Further, in the case of the locking structure as shown in the figure, in order to prevent the spring from coming into contact with the disc even when the pad is fully worn, the locking hole 7 is provided on the front surface of the back plate from the back plate. It is desirable to provide a groove 8 (see FIG. 4) that extends to the outer periphery and allow a part of the spring 4 (a portion along the front surface of the back plate) to be submerged in the groove. By doing so, the spring 4 is also prevented from rotating around the foot portion 4a as a fulcrum, so that the problem that the central portion of the spring comes into contact with the outer periphery of the disk D and breaks can also be solved.

In order to reduce the difference in spring force acting on points b and c, point a is preferably located in the center between points b and c, if possible.

[0016]

As described above, according to the present invention, the pad pressurizing point by the return spring is between the two points that generate sliding resistance, that is, the pad is constrained by the torque member to the radial outward movement of the disk and the retainer. Since the difference between the force of the return springs that are transmitted between the pad pressure points is reduced, the entire pad can be pushed back to the average point without increasing the spring force. It is useful for reducing drag during non-braking without increasing stroke and improving fuel efficiency.

[Brief description of drawings]

FIG. 1 is a view of a brake according to an embodiment as seen from a disc side with a caliper removed.

FIG. 2 is a top view showing the brake of the embodiment with the caliper and the torque member omitted.

FIG. 3 is a side view of the above.

FIG. 4 is a perspective view showing a modified example of a spring locking portion.

FIG. 5 is a partially cutaway top view of a conventional brake.

6 is a cross-sectional view taken along the line XX of FIG.

7A and 7B are views for comparing the force with which a pad contacts a disc, where FIG. 7A is a conventional device and FIG.

[Explanation of symbols]

 1 Caliper 2, 3 Pad 4 Return Spring 4a Foot 5 Torque Member 6 Retainer 7 Locking Hole 8 Groove a Pad Pad Pressing Point by Spring 4 b Pad Movement Limit Point to Disk Radial Direction c Pad Pressing by Retainer point

Claims (3)

(57) [Scope of utility model registration request] 1. A pair of friction pads for gripping a disk,
In a disc brake in which pressure is applied in a direction away from the center of the disc by a retainer attached to the pad slide part of the torque member, and pressure is applied in a direction away from the disc by a return spring attached across the disc between the pair of pads, A disk characterized in that the pressing point of the friction pad by the return spring is provided in a region sandwiched between the point where the torque member restrains the movement of the pad radially outward of the disk and the pad pressing point by the retainer. brake. 2. A foot which is bent in the axial direction of the disc is provided at both ends of the return spring, and the foot is inserted into a locking hole provided in the back plate of the friction pad from the front side of the back plate, and the return spring is provided at that part. The disc brake according to claim 1, wherein the pad is pressed by the above method. 3. The disc brake according to claim 2, wherein a groove for fitting a return spring is provided on the front surface of the back plate so as to extend from the locking hole to the outer periphery of the back plate.