SU1751539A1 - Drum-and shoe brake - Google Patents

Abstract

Use: in barreban-block brakes of vehicles. SUMMARY OF THE INVENTION: The brake comprises pads with end lugs mounted on the platter. On the latter there are radial guide surfaces mating with each other by means of supporting surfaces with the formation of radial grooves. The pads are installed with axle support by means of supporting surfaces on the end projections. Friction surfaces of the pads are located at their ends. 1 hp f-ly, 2 ill.

Description

The invention relates to machine building and can be used on vehicles.

Known Shoe brake containing brake drum connected to the wheel hub, the main disc, brake pads, located between the ends of the drive. The hinged pads rest on the adjusting screw and the hinges with the thread. The adjustment of the gap in this brake occurs when the adjustment screw is rotated. Despite adjusting the clearance between the pads, the pressure on the friction surfaces is unevenly distributed due to one-sided application of load to the ends of the pads, which leads to uneven wear of the pads and a decrease in the reliability and durability of the brakes.

The purpose of the invention is to increase reliability of operation and service life by increasing the uniform distribution of loads on the working surfaces.

The goal is achieved by the fact that in the shoe brake brake pads

made with arc brake surfaces at the ends and additional radial guiding surfaces that are in contact with the axis. The axis is fixed in the main disk. The end surfaces of the pads come into contact with the brake control fist.

The execution of blocks with brake arcing surfaces along the ends in contact with the surface of the brake drum during braking forms a wedge coupling, which makes it possible to increase the braking efficiency (an increase in the magnitude of the braking torque with the same dimensions) by obtaining the reduced slip friction coefficient

fnP where f is the coefficient of friction slip;

ft is the angle of the brake arc surfaces on the shoe.

In the proposed brake, the implementation of the pads with the end protrusion and the radial groove mounted on the axis provides a more uniform distribution

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with

vj SL

SL S Yu

pressures on these surfaces due to the possibility of radial displacement of the pads along the axis when a load from the control fist is applied to the end surfaces of the pads and to press the brake arc surfaces to the brake sub-drum.

This feature allows to increase the durability of the brake by providing a constant uniform pressing of the brake surfaces of the pads to the drum, regardless of the wear of the friction linings in the absence of an additional clearance adjustment mechanism.

Figure 1 shows the proposed drum brake; figure 2 - section aa in figure 1.

A kolodochny brake consists of a brake drum 1, a supporting disc 2 with a fixed axis 3, onto which brake pads 4 and 5 are installed with arc brake surfaces, 6 and 7, friction linings 8 and 9 fixed to them the projection 10 on one end portion and the radial groove 11, and in the other end portion end faces 12 coming into contact with the kupak 13 and the spring 14.

The brake works as follows

When acting on the brake pedal, the lever 15 creates a force on the knuckle 13, pushing the pads up until they press the arc friction lining 8 and 9 to the cylindrical surface of the drum 1. At the same time, as the friction forces and normal pressure appear, the pads 4 and 5 shift up the groove 11 along axis 3 and pressing the friction top plates against the surface of the drum 1. Braking occurs, while the load on the arc surfaces 6 and 7 with the friction linings 8 and 9 is evenly distributed, and the axis 3 perceives the reactive moment.

When the braking stops, the spring 14 returns the pads 4 and 5 to the initial position, pressing the notch 10 against the axis 3 with the groove 11 against the axis 3. Press the arc surfaces 6 and 7 with the friction lining 8

and 9 are mounted concentric to the surface of the drum with a radial clearance.

The arrangement of the friction arc surfaces at the ends of the pads and the possibility of their radial displacement allow for an increase in the braking torque and ensure uniform wear of the friction linings regardless of the radial clearance.

The advantages of the proposed brake are that it automatically ensures a uniform distribution of the load over the brake surfaces, regardless of wear and clearance, which allows increasing its reliability and durability. Performing the arc brake sections at the ends of the pads at an angle of / 45-20 ° allows to obtain a wedge interface on the arc surfaces of the pads.

and the drum, which provides an increase in braking torque of 1.5-2 times with the same brake dimensions.

Claims (2)

1. A drum-type brake comprising a brake drum, pads mounted on a support disc with end projections having radial guide surfaces and an axis in contact with said surfaces, characterized in that, in order to increase reliability and service life by increasing uniform distribution of loads on working surfaces, additional radial guide surfaces are made on the protrusions of the pads in contact with the axis and mating with the first guide surfaces with the formation of radial grooves by means of supporting surfaces on the protrusions located on the side of the external surfaces of the pads, while the pads are installed with support on the axis by means of supporting surfaces. 2. A brake according to claim 1, characterized in that the friction surfaces of the pads are located at their ends. ha