JPS6237260B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improvement of a disc brake, specifically, a drum brake is combined with a disc brake, and the drum brake is operated as a servo brake, thereby maintaining the stability of the braking effect, which is a characteristic of the disc brake. It relates to a disc brake that combines a drum brake with improved total braking effectiveness.

Currently, disc brakes have come to be installed on many vehicles in place of conventional drum brakes due to their superior and stable braking effectiveness, but in general, disc brakes have lower braking effectiveness than drum brakes. Therefore, many vehicles require a booster to supplement the force applied to the brake pedal.

However, in recent years, due to vehicle exhaust gas regulations, etc., it has become necessary to install an exhaust gas treatment device in the engine compartment.
As the space in the engine compartment tends to be limited, and at the same time, there is a trend toward smaller and lighter parts to reduce the weight of vehicles, there is a strong demand for downsizing or eliminating the above-mentioned booster.

The present invention was made in order to solve such a problem, and it combines a drum brake with a disc brake, uses the braking torque generated when the disc brake is operated as an input for the operation of the drum brake, and
The desired results were achieved by configuring this drum brake to work as a servo brake.

The gist of the present invention is to provide a caliper that presses a pair of friction pads against both sides of a disc rotor, a torque receiving member that receives the braking torque generated on both friction pads, and a pair of brake shoes that are applied to a drum by rotation of a cam. a drum brake device that generates braking torque when pressed by a brake member, and the torque receiving member and the cam are connected so that the cam rotates when the torque receiving member moves in response to the braking torque. A disc brake combined with a drum brake is characterized by the following.

That is, the present invention improves the total braking effectiveness while maintaining the stability of the braking effectiveness, which is a characteristic of disc brakes, by making the drum brake work as a servo brake for the disc brake.
This has the effect of making the above-mentioned booster smaller or unnecessary.

Further, the present invention has the advantage that the braking force is large because the two brake shoes act as drum brakes.

In the present invention, the disc brake is a floating caliper type hydraulic type, while the drum brake is a mechanical type that drives the brake shoe by the rotation of a cam, and the braking torque generated on the friction pads of the disc brake is It is desirable to transmit this operating input to the drum brake via a torque receiver that supports the friction pad to rotate the cam, in order to simplify the structure, facilitate manufacturing, and provide the product at low cost. . The present invention will be described in detail below based on embodiments shown in the drawings.

As shown in FIG. 1, internal and external friction pads 2, 2 for pressing against and applying frictional force to a disc rotor connected to a wheel, and a hydraulic cylinder 3 for driving the disc brake are incorporated into a caliper 1 of a disc brake. This is a floating caliper type disc brake in which the caliper 1 is slidably supported on a packing plate 5 of a drum brake via guide pins 4, 4, and this is supported by a torque receiver 6 that supports the friction pad 2. It has a structure in which it is connected to the cam 7 of the drum brake via.

On the other hand, the drum brake is constructed so that by rotating the cam 7, the brake shoes 8, 8 are pushed apart while expanding the shoe return spring 9, thereby exerting a frictional force on the drum portion of the disc rotor.

The drum brake according to the embodiment is a dual servo brake in which a strut 11 is sandwiched via a spring 10 at the end of both brake shoes 8, 8 on the opposite side to the side where the cam 7 is sandwiched. Unlike a normal drum brake in which the brake shoes 8, 8 are locked by holding an anchor between them, it has a self-servo action and has high braking effectiveness.

As shown in FIG. 2, the disc rotor has a hat shape in which a rotor part 12 for pressing the friction pad 2 and a drum part 13 for pressing the brake shoe 8 are integrally molded.

Furthermore, the friction pad (inner pad) 2, which is directly driven by the piston of the hydraulic cylinder 3 of the disc brake, is not fixed to the piston of the hydraulic cylinder 3, and can slide in the rotational direction of the disc rotor, and can also slide against the torque receiver 6. The piston is slidably supported in the driving direction of the piston.

The above torque receiver 6 and drum brake cam 7
A prismatic bolt 14 is inserted into a square hole provided in each of the prismatic holes, and a washer 15 is sandwiched between the prismatic bolts 14 and nuts 16 are tightened to firmly connect the prismatic bolts 14 to the packing plate 5 as their rotation axis. It has been stopped.

Next, the operating function of the disc brake combined with the drum brake of the present invention constructed as described above will be explained.

When hydraulic pressure is applied to the hydraulic cylinder 3 of the disc brake to drive the piston and press the friction pad 2 against the rotor part 12 of the rotating disc rotor to exert a frictional force thereon, the friction pad 2 receives braking torque from the disc rotor. .

This braking torque is transmitted to the cam 7 of the drum brake via the torque receiver 6, causing the cam 7 to rotate, thereby causing the brake shoes 8, 8 to extend the shoe return spring 9 while the drum of the disc rotor. It is pressed against the portion 13 and exerts a frictional force thereon.

Therefore, the lack of braking effectiveness of the disc brake can be compensated for by the drum brake, which functions as a servo brake.

Further, by setting the load on the drum brake to about half of the total braking force, instability in braking effectiveness, which is a drawback of drum brakes, can be reduced.

In the present invention, the same servo action can be obtained whether the vehicle is moving forward or backward.

As described above, the disc brake combined with the drum brake of the present invention improves the total braking effectiveness while maintaining the stability of the braking effectiveness that is characteristic of disc brakes, thereby increasing the brake pedal depression force by twice as much as conventionally required. This allows the power device to be made smaller or unnecessary.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a disc brake combined with a drum brake according to the present invention, and FIG. 2 is a sectional view showing an embodiment of a disc rotor used in the present invention. 1... Caliper, 2... Friction pad, 3... Hydraulic cylinder, 4... Guide pin, 5... Packing plate, 6... Torque receiver, 7... Cam, 8... Brake shoe, 9... Shoe return spring, 10... Spring , 11... Strut, 12... Rotor portion of disk rotor, 13... Drum portion of disk rotor, 14... Square column bolt, 15... Washer, 16...
Natsuto.

Claims (1)

[Claims] 1. A caliper that presses a pair of friction pads against both sides of the disc rotor, a torque receiving member that receives the braking torque generated on both friction pads, and a pair of brake shoes that are pressed against the drum section by the rotation of the cam to generate braking torque. and a drum brake device that generates a braking torque, wherein the torque receiving member and the cam are connected so that the cam rotates when the torque receiving member moves in response to braking torque. A disc brake that combines.