Loading and unloading switching valve for lorry-mounted crane

Abstract

The invention relates to a loading and unloading switching valve for a lorry-mounted crane. The loading and unloading switching valve for the lorry-mounted crane comprises a first overflowing valve, an electromagnetic switching valve, a second overflowing valve, an electric proportional flow valve, a pressure compensator and a throttling hole; the first overflowing valve is arranged between a quantifying pump pressure port pipeline and an oil tank pipeline; the quantifying pump pressure port pipeline is connected with the electromagnetic switching valve through a P port; the oil tank pipelineis connected with an electromagnetic valve through a T port; the electromagnetic switching valve is connected with a loading multi-way valve through a B port; and the electromagnetic valve is connected with an unloading supporting leg control system through an A port. The loading and unloading switching valve for the lorry-mounted crane has the following advantages: 1, the loading and unloading switching valve for the lorry-mounted crane is simple to operate, a single switching valve is not needed, loading and unloading switching depends on electric control, and error operation possibility isavoided; 2, each oil path system is provided with an independent overflowing protecting valve, pressure setting is conducted according to respective needed pressure, and high-pressure impact generatedby the supporting leg system is effectively avoided; and 3, the supporting leg control system adopts a load sensitive proportional control mode, the flow is distributed according to requirements, theoperation micromotion property is high, and the system is efficient in throttling.

Description

technical field [0001] The invention relates to a vehicle-mounted switching valve for a truck-mounted crane, which belongs to the technical field of hydraulic control. Background technique [0002] The hydraulic control system of the truck-mounted crane is mainly divided into two parts: the hydraulic control part of the actuator on the vehicle and the hydraulic control part of the outriggers on the vehicle; these two parts work completely independently during the entire lifting operation, that is, during the entire working process , first carry out the outrigger operation part, support the whole car, and then work on the actuator on the vehicle; during the entire work process, it is not allowed to operate the outriggers on the vehicle during the process of manipulating the actuator on the vehicle. [0003] At present, in the design of the hydraulic system of the truck-mounted crane, there are mainly the following control methods for the control of getting on and off the car:...

AI Technical Summary

Problems solved by technology

[0008] The disadvantage of the first control method is: the control of the hydraulic system for getting on and off the car is independent of each other, and there is no hydraulic interlock function, which may easily cause misoperation and cause accidents;

[0009] The disadvantage of the second control method is: the control of the hydraulic system for getting on and off the car is independent of each other, and the outrigger selection control valve needs to be equipped separately. The outrigger control is controlled by an on-off valve, the proportional control performance is poor, and the cost is high;

[0010] The disadvantage of the third control method is: the control of the hydraulic system for getting on and off the car is independent of each other, and the outrigger selection control valve needs to be equipped separately. The same, therefore, tends to cause high pressure shocks when the outriggers are operated;

[0011] The disadvantage of the fourth control method is: the control of the hydraulic system for getting on and off the car is independent of each other, and the outrigger control valve needs to be equipped separately, there is no outrigger selection function, the linkage operation of the outriggers is inconvenient, and the cost is high

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