Novel torque limiting valve and hydraulic-control torque limiting system with novel torque limiting valve

Abstract

The invention discloses a novel torque limiting valve and a hydraulic-control torque limiting system with the novel torque limiting valve. The novel torque limiting valve and hydraulic-control torque limiting system with the novel torque limiting valve comprises a torque limiting unloading valve and a torque limiting control valve. A control oil port of the torque limiting unloading valve is communicated with a control oil port of the torque limiting control valve. A first oil port of the torque limiting unloading valve and a second oil port of the torque limiting unloading valve are communicated with a first derricking cylinder through a one-way balance valve. A third oil port of the torque limiting unloading valve and a fourth oil port of the torque limiting unloading valve are communicated with a second derricking cylinder through a first bidirectional balance valve. A fifth oil port of the torque limiting unloading valve is communicated with a telescopic cylinder through a second bidirectional balance valve. A first oil port of the torque limiting control valve is communicated with a rodless cavity of the first derricking cylinder, and a second oil port of the torque limiting control valve is communicated with a rod cavity of the first derricking cylinder. The novel torque limiting valve and hydraulic-control torque limiting system with the novel torque limiting valve has the advantages that the unloading part of the torque limiting valve can control five actions; five groups of one-way valves and a hydraulic control one-way valve from a main oil way, the flow capacity is strong, the oil ways are independent, and interference does not exist.

Description

technical field [0001] The invention relates to a novel torque limiting valve and a hydraulic control torque limiting system provided with the valve, belonging to the technical field of truck-mounted cranes. Background technique [0002] In recent years, with the development of market and technology, the lifting capacity of truck-mounted cranes has been continuously improved, and the application of knuckle-arm cranes in our country is increasing day by day, and the requirements for their operation safety are also increasing. The function of the torque limiting system is to limit the operating torque and play the role of safety protection. Therefore, the moment limiting system, as the main safety protection system of the truck-mounted crane, has gradually become the research focus of the truck-mounted crane. [0003] In the prior art, a lot of explanations have been made on the electro-hydraulic control torque limiting device of cranes, but this kind of torque limiting metho...

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Problems solved by technology

[0003] In the prior art, a lot of explanations have been made on the electro-hydraulic control torque limiting device of cranes, but this type of torque limiting method has problems such as complex system, large number of components, high cost and low reliability

In order to effectively solve this kind of problem, the existing patent proposes a hydraulically controlled torque limiting system for a knuckle boom truck-mounted crane. The torque limiting valve can only limit three dangerous actions, and it needs to cooperate with the secondary pressure limiting plug-in of the directional control valve to control it. The first luffing lifting, the first luffing lowering, the second luffing lifting, telescopic extension four dangerous actions, the torque limiting system is complicated, and the moment limiting unloading part and the moment limiting control part are integrated structure, for The straight-arm truck-mounted cranes and folding-arm truck-mounted cranes in the truck-mounted cranes require different numbers of dangerous actions to be restricted (three dangerous actions are required for straight-arm truck-mounted cranes, and five dangerous actions are required for folding-arm truck-mounted cranes), This type of valve cannot meet the torque limit requirements of truck-mounted cranes with different numbers of dangerous actions at the same time; Finally, the handle of the multi-way reversing valve returns to the neutral position, the pilot valve of the unloading valve is still in the unloading state, the main valve of the unloading valve returns to the closed state under the action of the spring force due to the cut-off of the pressure oil circuit, and the unloading main oil circuit is still in the non-loading state. The unloading state causes the crane to move after the force limit, etc.

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