JPS6336181Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a fail-safe multi-disc brake used, for example, in cargo handling equipment.

Conventionally, this kind of disc brake is known, for example, as disclosed in Japanese Patent Application Laid-Open No. 50-36872. However, in conventional multi-disc brakes, when hydraulic pressure is not acting on the piston that releases the braking force, the piston moves freely inside the cylinder.
Therefore, if the piston is subjected to vibrations or the like, it is possible that the piston is pushed by the biasing means and separates from the contact plate that presses the rotor disk and the brake plate.

However, if hydraulic pressure acts on the piston in such a state, the brake will not be released until the gap between the two is filled, resulting in poor responsiveness to commands and unnecessary movement of the piston in the initial stage. As a result, extra hydraulic oil is consumed.

In addition, in Japanese Patent Application Laid-open No. 49-81770, an end plate is screwed to the end face of the piston, and this plate is brought into contact with the end face of the hub that is integrated with the pressure plate for pressurizing the friction plate, so that the piston can be moved to the hub. A technique is shown that addresses the above problem by holding the brake at the brake release force transmission point. However, according to this technology,
A set screw for the end plate, means for locking the screw, and a screw hole for screwing the set screw are required, which increases the number of parts and the number of man-hours for machining the parts, which is economically disadvantageous. Furthermore, since the end plate exists in an atmospheric chamber, there is a risk of rusting due to saturated moisture in the atmosphere.

Furthermore, since the end plate is a flat plate, there is a risk that machining errors in the piston, the hub, and the mounting groove of the snap spring that engages both may accumulate, creating a gap between the end surface of the hub and the end plate.
The reliability of the piston and tract is also lacking.

Therefore, this idea was developed to create a multi-plate disk that maintains a stable contact state between the piston and the contact plate at all times, and at the same time solves the problem of an increase in the number of parts, the number of machining processes, and rusting of the means for maintaining the contact state. Its purpose is to provide a brake.

Hereinafter, the configuration of this invention will be explained based on an embodiment shown in the attached drawings.

As shown in FIG. 1, the disc brake according to this invention includes a plurality of rotor discs 2 that rotate integrally with a coupling boss 1 serving as an input shaft, and a brake plate 3 that engages with each disc 2 to stop its movement. and,
A contact plate 4 that brings this brake plate into pressure contact with the rotor disk 2, and a biasing means 5 that constantly presses this plate toward the disk 2 to generate a braking force.
and an annular piston 6 opposing this to release the braking force.

The coupling boss 1 is fixed to, for example, an output shaft B of a hydraulic motor A, and the rotor disk 2 is supported by the boss 1 so that it slides in the axial direction but is fixed in the circumferential direction. has been done.

On the other hand, the brake plates 3 which engage with the disks 2 are supported on the inner surface of the inner housing 7 which is connected to the end face of the motor A so that they can slide in the axial direction like the rotor, but their circumferential movement is restricted, and only the rightmost brake plate 3' has its axial movement restricted as well.

Further, the contact plate 4 is prevented from rotating at any position on its outer periphery by inserting a dowel pin 9 which is locked at one end into the inner housing 7 and at the other end into the outer housing 8. A biasing means 5, such as a disc spring, is in contact with one surface, and a rotor disk 2 is in contact with the other surface.
The end faces of the two are in contact with each other.

Further, the piston 6 is housed in an annular cylinder 10 formed at the joint between the housings 2 and 3 at the outer circumference of the disk, and its tip abuts against the outer circumference of the other surface of the contact plate 4. Therefore, when hydraulic pressure acts within the cylinder 10 and the piston 6 moves forward, the contact plate 4 is pushed to the left and the braking force is released.

This idea is based on the multi-disc brake having the above-mentioned configuration, in which a retract spring 20 is interposed between the end surface of the cylinder 10 on the liquid chamber side and the rear surface of the piston 6, and the force of this spring is used to retract the piston. The piston is characterized in that it is always biased in the direction of bringing the piston into pressure contact with the contact plate 4, and the presence of the spring 20 prevents the piston from separating from the contact plate.

Further, since the spring 20 is located in the liquid chamber and is protected by the rust preventive agent mixed in the hydraulic fluid, there is no need to worry about rusting.

As shown in FIG. 2, the retract spring 20 includes a plurality of elastic pawls 22 cut and raised on a ring-shaped plate 21 formed of spring steel.
Since the piston is biased by the elastic claw 22, errors in the axial machining of the piston, etc. are absorbed by the deflection of the claw 22, and the retracting function is stably performed. This spring 2
0, by providing the elastic claws 22 at fixed pitches in the circumferential direction, a substantially uniform return force can be applied to the entire circumference of the piston.

Note that, as a matter of course, the repulsive force of the retract spring 20 acts in the direction of reducing the force of the urging means 5, so the force of this spring is set so as not to adversely affect brake braking.

As described above, this idea prevents gaps from forming between the piston and the contact plate by providing a retract spring in the cylinder formed in the housing that biases the piston that releases the braking force toward the contact plate. This improves responsiveness when releasing the brake and eliminates unnecessary consumption of hydraulic fluid.

In addition, the retract spring has a structure in which a plurality of elastic claws are cut and raised on a ring-shaped plate and placed inside the liquid chamber of the cylinder, so no special parts or processing are required to hold the spring. In addition, the rusting of the spring can be effectively prevented, and the retract function is also stabilized. It is possible to achieve advantageous positioning in terms of vibration, and the structure can also be simplified.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a multi-disc brake to which this invention is applied, and FIG. 2 is a perspective view showing an example of a retract spring. 1... Couple spring boss, 2... Rotor disk, 3... Brake plate, 4... Contact plate,
5... Urging means, 6... Piston, 7... Inner housing, 8... Outer housing, 9...
... Knock pin, 10 ... Cylinder, 20 ... Retract spring, 21 ... Ring-shaped plate,
22...Elastic claw.

Claims (1)

[Scope of utility model registration request] A plurality of rotor disks that rotate together with the input shaft, a brake plate that engages with each disk to stop its movement, a contact plate that presses the brake plates and the disks, and always presses the plate in the direction of contacting the disks. In a multi-disk disc brake including a biasing means for generating a braking force and an annular piston opposing the biasing means for releasing the braking force by the biasing means, in a liquid chamber of an annular cylinder housing the piston, A brake comprising a ring-shaped plate with a plurality of elastic pawls cut and raised thereon, and a retract spring that urges the piston in a direction to bring the piston into constant contact with a contact plate by the elastic pawls.