A forklift hydraulic system with double pump oil supply and energy recovery

Abstract

The invention relates to a forklift hydraulic system with energy recovery and double-pump oil supply functions. The forklift hydraulic system comprises an oil tank, a first oil pump, a motor, a multiway valve, two lifting oil cylinders, two inclined oil cylinders, a steering oil cylinder, a load sensing steering gear, a second oil pump, a directional control valve and a speed limit valve, wherein the multiway valve consists of an oil inlet and return valve plate assembly, an inclined reversing valve plate and an oil inlet valve plate, and is a plate type multiway valve; a three-position eight-way lifting reversing valve and a first main safety valve are arranged in the oil inlet and return valve plate assembly; the inclined reversing valve plate comprises an inclined three-position six-way reversing valve, a first oil adding overload valve and a second oil adding overload valve; the oil inlet valve plate comprises a split-flow valve, a priority valve, a steering safety valve and a second main safety valve. The forklift hydraulic system is suitable for not only hybrid power forklifts but also electric forklifts. For example, after a 7t electric forklift is charged once, according to the test results of an energy consumption test method of the whole vehicle, the energy consumption of the system is reduced by 25%, and the working cycle time of the whole vehicle is prolonged by 50 minutes.

Description

technical field [0001] The invention belongs to the field of hydraulic technology, in particular to a forklift hydraulic system. Background technique [0002] The forklift uses the lifting system to complete the processes of picking up, lifting, stacking, and stacking the goods. When the forklift is picking up goods and descending, it uses various throttling methods to control the descending speed of heavy objects. In this process, the gravitational potential energy is all converted into heat energy through the throttle valve. It will not only cause the temperature rise of the hydraulic system, but also affect the reliability of the system and components and the working efficiency of the whole vehicle. With the increasingly tense international energy supply and the increasing awareness of environmental protection worldwide, green and energy saving have become the future development trend of technologies and products in various industries. The development of the situation ...

AI Technical Summary

Problems solved by technology

The foreign forklift lowering energy recovery system we know is to meet the lifting and lowering oil circuit switching requirements by connecting one or two sets of electromagnetic reversing valves, which is costly and complicated to control.

Patent No. ZL201120038176.8 "Hybrid Forklift Hydraulic System" and Patent No. ZL201220118243.1 "An Energy-Saving Forklift Hydraulic System with Energy Recovery" technical scheme is: the pressure oil output by the double pump is in the inlet of the lift reversing valve plate The oil ports converge, and then output to the lifting cylinder through the single oil passage inside the lift reversing valve plate. The double pump oil return is also carried out in the single oil passage inside the lift reversing valve plate. The design is limited. When the double pumps work at the same time to supply the hydraulic oil of the lifting system that requires a large flow, the pressure loss is large and the system consumes a lot of energy; Need, the oil passage is long, the pressure loss is also large, and the energy consumption of the system increases

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