Four-speed output air pressure trailer brake valve

Abstract

The invention provides a four-gear output air pressure trailer brake valve which comprises an upper cover, an upper body, a lower body, a lower cover, a gear selection assembly, a servo piston, a control cavity change-over valve, an air outlet cavity change-over valve, a control piston assembly, a control port, an air inlet port and an air outlet port. The gear selection assembly comprises a gear rotary knob, a rotating shaft and a selection piece. The rotating shaft is arranged on the upper cover and connected with the gear rotary knob; the selection piece is arranged on the rotating shaft. The servo piston is arranged between the upper body and the lower body, a main control cavity and an auxiliary control cavity are formed by the servo piston and the upper body, and a main air outlet cavity and an auxiliary air outlet cavity are formed by the servo piston and the lower body. The control cavity change-over valve is connected with the rotating shaft and the selection piece and enables the main control cavity to be communicated or not communicated with the auxiliary control cavity. The air outlet cavity change-over valve is connected with the rotating shaft. The control piston assembly is connected with the air outlet cavity change-over valve and arranged between the main air outlet cavity and the auxiliary air outlet cavity, and the air outlet cavity change-over valve drives the control piston assembly to move and enables the main air outlet cavity to be communicated or not communicated with the auxiliary air outlet cavity.

Description

technical field [0001] The invention relates to the field of vehicle brake control, and in particular to a four-speed output air pressure trailer brake valve. Background technique [0002] The trailer brake valve of the trailer and semi-trailer is a secondary valve in the brake system of the car train, which is used to control the brake valve of the rear axle of the trailer and semi-trailer. Because it is far away from the front of the car and the brake pipeline is long, it cannot be directly braked by the brake valve on the main car. Instead, the brake air pressure of the main car is used as the control air pressure of the trailer brake valve to control the brakes on the rear axle of the trailer and semi-trailer. At present, emergency relay valves, synchronous emergency relay valves, and other three-axle relay valves used in trailers and semi-trailers have problems such as brake failure when heavy loads, and tire wear when dragging when unloaded. [0003] Although the air ...

AI Technical Summary

Problems solved by technology

[0004] And further, in the existing trailer or semi-trailer, the synchronous emergency brake valve is used to realize rapid braking, but the speed of releasing the brake is relatively slow, and the speed of releasing the brake is obviously slower than that of the front wheels of the vehicle, resulting in Rear wheel lag, slow recovery, severe wear of brake shoes, etc.

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