Novel variable-speed operating valve

Abstract

The invention relates to the improvement of a variable-speed operating valve of a power shift gearbox of engineering machinery. The variable-speed operating valve comprises a valve body, a cut-off valve, a distribution valve and the like, and is characterized in that the same axis of the same valve body is further provided with a regulator device overflow valve comprising an overflow valve core, a pressure adjusting spring and the like, and a buffer modulation device buffer valve comprising a limit rod, a buffer spring, an accumulator plunger, a buffer slide valve and the like; and both the regulator device overflow valve and the buffer modulation device buffer valve are separated by a lock sheet, and are communicated with an oil passage. The pressure shock when shifting is reduced, the flexible combination of a clutch is realized, and gear shifting hysteresis caused by the fatigue of the pressure adjusting spring is solved, thereby improving the reliability and prolonging the service life of the variable-speed operating valve. The novel variable-speed operating valve totally agrees with the installing size of the conventional gearbox; therefore, the novel variable-speed operating valve has excellent execution and popularization value.

Description

Technical field [0001] The invention relates to a speed change control system of a power shift gearbox for engineering machinery, especially the improvement of a hydraulic shift speed change control valve in the transmission. Background technique [0002] The operating conditions of construction machinery are relatively harsh, the driving conditions are complicated, and gear shifting is frequent. Taking a loader as an example, each operation cycle needs to shift gears 4 to 5 times, and the gears are shifted nearly a thousand times per hour in continuous operation. At present, most of the loader power shift control systems used in domestic construction machinery use machine-hydraulic transmission control valves. For example, the ZL40 / 50 power shift transmission of the domestic loader generally adopts the hydraulic shift control valve, because the valve is not designed to be smoothly combined with the control element, the clutch is combined roughly at the moment of shifting, ...

AI Technical Summary

Problems solved by technology

For example, the ZL40 / 50 power shift transmission of the domestic loader generally adopts the hydraulic shift control valve, because the valve is not designed to be smoothly combined with the control element, the clutch is combined roughly at the moment of shifting, and the impact force is large, resulting in a large vibration in the transmission system. The dynamic load accelerates the damage of parts; moreover, the structure of the existing variable speed control valve is not very reasonable, and the deformation amplitude of the pressure regulating spring is too large, which makes the spring easy to fatigue, easy to damage, short life and other problems, resulting in often lagging phenomenon in shifting

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