Speed change valve used for heavy machinery

Abstract

The invention relates to a speed change valve used for heavy machinery. A valve body is provided with a main channel inlet and a main channel outlet, one end of a valve element is provided with a spring, the outer end of an end cover is provided with a regulating bolt, a backstop is arranged at the top end of the regulating bolt of a right end cover, the backstop is inserted into a hole at the inner end of the end cover, the bottom of the hole at the inner end of the left end cover is provided with a groove, an oil cavity is formed between the groove and the end face of the valve element, the end cover is internally provided with an end cover bypass channel, one end of the end cover bypass channel is communicated with the groove, the end cover bypass channel is provided with a needle throttle valve and a small-diameter sliding valve controlled by an electromagnet, the valve body is provided with a valve body bypass channel, one end of the valve body bypass channel is communicated with the main channel inlet, and the other end of the valve body bypass channel is communicated with the other end of the end cover bypass channel. The speed change valve disclosed by the invention has the beneficial effects that variation of oil mass flowing out is smooth and has no sudden change, the slope of a speed change curve of a hydraulic cylinder is adjustable, the speed value of a working hydraulic cylinder before the end of run is adjustable, the price is low, and the speed change valve disclosed by the invention can be widely applied to a hydraulic system of heavy machinery equipment.

Description

technical field [0001] The invention belongs to the technical field of variable speed valves, in particular to a variable speed valve for heavy machinery. Background technique [0002] In the hydraulic system of heavy machinery, the reversing valve is used to control the medium and long stroke hydraulic cylinders. Controlled by a reversing valve, the flow into the oil cylinder cannot be adjusted. The speed of the oil cylinder is constant during operation. When the piston of the oil cylinder just starts or runs to the end, the speed will suddenly increase or decrease. The working speed curve is as follows: figure 1 . Depend on figure 1 It can be seen from the curve that there is a sudden change in speed at the characteristic points 0, A, B, and C, which brings a large impact load, which not only poses a safety hazard, but also reduces the service life of the equipment. In order to reduce the impact load without lowering production efficiency, taking end point control as an...

AI Technical Summary

Problems solved by technology

[0003] Proportional valves are used in the hydraulic system of heavy machinery, which can only partially alleviate the impact problem, and the purchase cost is high and the cycle is long, which affects the production cycle of the equipment

And the structure is more complex

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