Pressure compensation type hydraulic pump, rotating speed control system, rotating speed control method and engineering machinery

Abstract

The invention relates to engineering machinery, and specifically discloses a pressure compensation control type hydraulic pump. The hydraulic pump comprises an electric proportional pressure compensator, a hydraulic pump, a hydraulic control reversing valve and a servo piston, the electric proportional pressure compensator can be electrically connected with a controller, a first hydraulic controlport of the hydraulic control reversing valve is connected with an internal oil drainage oil way through the electric proportional pressure compensator, the first hydraulic control port is connected to an internal output oil way through a hydraulic control oil-inlet oil way provided with a first throttling valve, a second hydraulic control port of the hydraulic control reversing valve is connectedwith the internal output oil way, and the pressure difference between the opening pressure of the electric proportional pressure compensator and the pressure of an oil outlet of the hydraulic pump can drive the hydraulic control reversing valve to reverse. In this way, a rodless cavity of the servo piston selectively communicates with the internal output oil way or the internal oil drainage oil way. In addition, the invention further discloses a rotating speed control method, a rotating speed control system and engineering machinery. According to the hydraulic pump, the output flow of the hydraulic pump can be stabilized at a required value.

Description

technical field [0001] The present invention relates to engineering machinery, in particular to a method for controlling the rotational speed of heat dissipation equipment for engineering machinery. In addition, the present invention also relates to a pressure compensation control hydraulic pump, a speed control system for heat dissipation equipment of construction machinery and construction machinery. Background technique [0002] During the operation of large-scale construction machinery, part of the pressure energy of its hydraulic system will be converted into heat energy, which will increase the oil temperature of the hydraulic system. In order to maintain the temperature of the hydraulic oil within a reasonable range, it is necessary to use heat dissipation equipment to dissipate heat from the hydraulic oil. Large-scale construction machinery such as excavators and loaders generally adopt an independent heat dissipation control system, that is, the input shaft of the ...

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Problems solved by technology

[0004] However, during the working process of construction machinery, the rotational speed of the engine 2 will change with the change of the load, and the change of the rotational speed of the engine 2 will cause the rotational speed of the cooling pump 1 to change, so that the output flow of the cooling pump 1 will also change, and the output flow of the cooling pump 1 will also change. Fluctuations in the output flow will lead to fluctuations in the speed of the fan motor 3, resulting in fluctuations in the speed of the fan 4, and the speed of the fan 4 cannot be stabilized at the required value. This affects the cooling effect of the hydraulic system on the one hand, and on the other hand Makes the fan 4 make a lot of noise

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