JPS5813763B2 - disc brake device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a disc brake device, in particular, a brake lever is pivotally supported on a brake caliper that slidably supports a friction pad, and the rotation operating force to be applied to the brake lever is provided on the brake caliper. The present invention relates to a type of device in which a cam mechanism converts the force to move the friction pad toward the brake disk, thereby bringing the friction pad into pressure contact with the brake disk.

In the above disc brake device, when the rotational stroke of the brake lever increases by more than a predetermined value due to wear of the friction pad, the above wear is reduced by converting the increased amount into a displacement of the friction pad toward the brake disc. BACKGROUND ART Conventionally, brake pads are known that have a so-called pad wear compensation function that compensates and maintains the rotational stroke of the brake lever substantially constant.

However, in the conventional device, the mechanism for achieving the above-mentioned pad wear compensation function includes, for example,
As shown in Publication No. 78, a ratchet type one-way clutch with a relatively large number of parts and a complicated structure was used, which resulted in problems such as high cost and easy failure, and the wear of the friction pads. However, the rotation stroke of the brake lever can be corrected until the feed pawl of the one-way clutch moves from one tooth of the ratchet wheel to the next tooth.
That is, the operating stroke of the brake lever repeats gradual increases and rapid decreases as the friction pad wears out, and there is a problem in that it cannot be kept accurately constant at all times.

The present invention has been proposed in view of the above, and has a simpler structure and fewer failures than the conventional ones, and can always adjust and maintain the operating stroke of the brake lever to perform appropriate braking operations at all times. It is an object of the present invention to provide a disc brake device.

The present invention also provides a brake caliper in which a friction pad facing the side surface of a brake disc is slidably but not rotatably supported in the axial direction of the brake disc, and one end is threaded into a self-locking nut fixed to the brake caliper. The back surface of the friction pad is supported via a brake lever movably supported on the support shaft at the other end of the support shaft which is connected to the support shaft and is parallel to the axis of the brake disc, and the brake lever and the friction pad are connected to each other. A cam mechanism is provided between the brake levers for converting the rotational operating force of the brake lever into a pressing force of the friction pad against the brake disc, and a coil spring with a constant tightening force is provided on the clutch drum provided on the support shaft. When the brake lever is connected to the target brake lever with a certain amount of play left at one end of the coil spring, and when the brake lever is rotated in one direction, when the tightening force of the coil spring increases, the coil spring is connected to the clutch drum and rotates the support shaft to compensate for wear of the friction pad, and when rotating in the other direction, when the tightening force of the coil spring decreases, the coil spring is connected to the clutch drum. It is characterized by the fact that it slides on the drum.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
is a brake disc that rotates together with the wheel, and the brake caliber 2, which is formed in an inverted U shape as a whole so as to straddle the upper part thereof, has a pair of front and rear sliding shafts 3, 3 parallel to the axis of the brake disc 1. , is slidably supported by a vehicle body (not shown) via both shafts 3, 3.

A friction pad 4 is bonded to the inside of the first arm 2a of the brake caliper 2, which faces one side of the brake disc 1, by adhesive or the like.
A back metal 5a of the friction pad 5 facing the other side is slidably suspended.

A brake lever 7 rotatably supported on a support shaft 6 parallel to the axis of rotation of the brake disc 10 is disposed on the back of the back metal 5a, and one end of the support shaft 6 is connected to the brake lever 7 via the brake lever 7. It supports the back surface of the friction pad 5, that is, the back metal 5a.

The brake lever 7 has three chevron-shaped cams 8, 88 arranged at equal intervals on a concentric field surrounding the spindle 6, which are lowered to the front, and these are attached to the three cams 8, 88 on the corresponding back plate 5a. are fitted in the recesses 9, 9.9, respectively.

The chevron-shaped cams 8, 8, 8 and the recesses 9, 9.9 constitute a cam mechanism C of the present invention.

An operating wire 10 for rotating the brake lever 7 in the actuation direction a and a torsion coil type return spring 11 for constantly pressing it in the release direction b are connected to the arm portion of the brake lever 7.

The release position of the brake lever 7 is regulated by the arm portion of the brake lever 7 being received by a stopper 12 that projects laterally from a part of the outer periphery of the back metal 5a.

The support shaft 6 includes a threaded portion 14 that is screwed into and supported by a self-locking nut 13 fixed to the second arm portion 2b of the brake caliper 2, and a clutch drum 1 adjacent to the brake caliper 7.
5, the self-locking nut 13 has a nut body 13
A lock pawl 1 that frictionally engages with the outer periphery of the threaded portion 14 is disposed inside a.
6.16 is installed, and the lock claw 16.16
This frictional resistance prevents the threaded portion 14 from rotating unless a rotational torque of a certain value or more is applied to the threaded portion 14.

The threaded portion 14 is formed into a left-hand thread in the illustrated example so that it advances toward the brake lever 7 when it is rotated in the operating direction a of the brake lever 7.

A coil spring 17 having a constant tightening force is fitted to the outer periphery of the clutch drum 15, and its outer bent end 17a is engaged with a locking hole 18 provided in the brake lever 7.

When this coil spring 17 rotates its bent end 17a in the actuation direction a of the brake leper 7, the tightening force increases and is immediately connected to the clutch drum 15, and when the coil spring 17 rotates in the opposite direction b, the tightening force immediately decreases. However, the coil cannot resist the rotational resistance of the self-lock nut 13 and slips on the clutch drum 15. Therefore, in the illustrated example, the winding direction of the coil is left-handed.

The diameter of the locking hole 18 is set to be slightly larger than that of the bent end 17a, and the difference in diameter, that is, the play, is approximately equal to the total distance normally formed between the brake disc 1 and each friction pad 4, 5. handle.

Next, the operation of this embodiment will be explained.

Now, when the brake lever 7 is rotated in the operating direction a by pulling the operation wire 10, the angle-shaped cam 8 of the brake lever 7 is rotated.
, 8.8 tries to escape from the recesses 9, 9, 9 of the back metal 5a and presses the back metal 5a forward to the right in FIG. As a result, both friction pads 4 and 5 are applied with clamping pressure, and the brake disc 1
Brake it by applying equal pressure to it.

By the way, as mentioned above, the bending 1 terminal 1 of the coil spring 17
7a and the locking hole 18 of the brake lever 7 approximately corresponds to the total gap normally formed between the brake disc 1 and each of the friction pads 4 and 5, so the brake lever 7 can fit into the clearance. When rotated by the corresponding angle, both friction pads 4, 5 come into pressure contact with the brake disc 1.

When each of the friction pads 4 and 5 wears out due to sliding contact with the brake disc 1 and the brake lever 7 further rotates in the operating direction a, the bending end 17a rotates together with the brake lever 7 for the first time. Coil splash 1
In order to tighten the clutch drum 15 even more strongly, the rotational torque of the brake lever 7 is transmitted to the support shaft 6 without slipping between them, and the rotational torque causes the threaded portion 1 to tighten.
4. Rotate the self-lock nut 130 against rotational resistance.

As a result, a relative displacement occurs in the self-locking nut 13 and the threaded part 14 in the axial direction, and the support shaft 6 moves to the right in FIG. 2 moves to the left together with the friction pads 4, thus the wear of each friction pad 4, 5 is compensated.

Next, when the pulling of the operating wire 10 is stopped, the return spring 11
0 When the brake lever 7 is rotated in the release direction b by a strong restoring force, the brake lever 7 rotates by an angle corresponding to the play between the bent end 17a and the locking hole 18, and then the bent end 17a is rotated. The coil spring 17 rotates through the coil spring 17, but as the coil spring 17 weakens the tightening force against the clutch drum 15, it slips on the clutch drum 15 without being able to resist the rotational resistance of the self-locking nut 13, and the self-locking nut 13 slides. The lock nut 13 and the threaded portion 14 do not change their previously compensated relative positions at all.

Therefore, when the brake lever 7 returns to the release position where it abuts the stopper 12, substantially the same amount of gap is formed between the brake disc 1 and each of the friction pads 4, 5 as at the beginning.

In the present invention, the thread direction of the threaded portion 14 and the winding direction of the coil spring 17 are set opposite to those of the above embodiment, so that when the brake lever 7 is rotated backward, the friction pad 4,
The wear compensation function described in No. 5 may also be performed.

As described above, according to the present invention, in the brake caliper 2,
A friction pad 5 facing the side surface of the brake disc 1 is slidably but non-rotatably supported in the axial direction of the brake disc 1, and one end is screwed into a self-locking nut 13 fixed to the brake caliper 2. The back surface of the friction pad 5 is supported on the other end of the support shaft 6 parallel to the axis of the brake disc 1 via a brake lever 7 rotatably supported on the support shaft 6. A cam mechanism C is provided between the brake lever 5 and the brake lever 7 to convert the rotational operating force of the brake lever 7 into a pressing force of the friction pad 5 against the brake disc 1. A coil spring 17 having a certain tightening force is fitted, and the brake lever 7 is connected to one end of the coil spring 17 with a certain play. When the brake lever 7 rotates in one direction, the When the tightening force of the coil spring 17 increases, the coil spring 17 connects with the clutch drum 15 and rotates the support shaft 6 to compensate for the wear of the friction pad 5, and when rotating in the other direction. When the tightening force of the coil spring 17 decreases, the coil spring 17 slides on the clutch drum 15, so when the brake lever 70 is rotated, the rotation stroke of the lever 7 is changed to an appropriate value due to wear of the friction pad 5. If it exceeds even slightly, the brake lever 7 is immediately connected to the support shaft 6 by the coil spring 17, and the shaft 6 can be rotated against the rotational resistance of the self-locking nut 13, and this rotation causes Therefore, the wear of the friction pad 5 can be automatically compensated for, and the rotational stroke of the brake lever 7 can be immediately corrected to the original proper value, and as a result,
The operating stroke of the brake lever 7 is always kept constant, so that an appropriate braking operation can be performed at all times.

Moreover, the mechanism for converting the increase in the rotational stroke of the brake lever 7 into the displacement of the friction pad 5 toward the brake disc 1 is composed of extremely simple members such as the self-locking nut 13 and the coil spring 17. Unlike the conventional device, there is no need to use a ratchet type one-way clutch with a complicated structure, and therefore the overall structure is extremely simple, reducing costs and reducing failures.

[Brief explanation of the drawing]

FIG. 1 is a side view of a disc brake device showing one embodiment of the present invention, and FIG. 2 is a sectional view taken along line A--A. 1...brake disc, 2...brake caliper, 5
...Friction pad, 6... Support shaft, 7... Brake lever,
13...Self-lock nut, C...Cam mechanism, 15...
...Clutch drum, 17...Coil spring.

Claims (1)

[Claims] 1 A friction pad 5 facing the side surface of the brake disc 1 is supported on the brake caliper 2 so as to be slidable in the axial direction of the brake disc 1 but not rotatable, and one end is attached to the self-lock knight 13 fixed to the brake caliper 2. The rear surface of the friction pad 5 is supported on the other end of the support shaft 6 which is screwed together and parallel to the axis of the brake disc 1 via a brake lever 7 which is rotatably supported on the support shaft 6, A cam mechanism C is provided between the brake lever 7 and the friction pad 5 for converting the rotational operating force of the brake lever 7 into a pressing force of the friction pad 5 against the brake disc 1. Installed clutch drum 15K,
A coil spring 17 having a certain tightening force is fitted, and the brake lever 7 is connected to one end of the coil spring 17 with a certain play, and when the brake lever 7 rotates in one direction, When the tightening force of the coil spring 17 increases, the coil spring 17 connects to the clutch drum 15 and rotates the support shaft 6 to compensate for the wear of the friction pad 5, and when rotating in the other direction. . A disc brake device, wherein when the tightening force of the coil spring 17 decreases, the coil spring 17 slides on the clutch drum 15.