Dual-pump confluent energy-saving type forklift hydraulic system

Abstract

The invention relates to a dual-pump confluent energy-saving type forklift hydraulic system. The dual-pump confluent energy-saving type forklift hydraulic system comprises an oil tank, a first oil pump, a second oil pump, a multiway valve, tilting oil cylinders, lifting oil cylinders and a steering oil cylinder. The multiway valve is composed of an oil inlet valve plate, a lifting reversing valve plate, a tilting reversing valve plate, a fitting reversing valve plate and an oil return valve plate. The multiway valve is internally provided with an annular oil return passage and a center oil passage, wherein the center oil passage is communicated with the lifting reversing valve plate, the tilting reversing valve plate, the fitting reversing valve plate and the oil return valve plate. The oil inlet valve plate is composed of a priority valve and a steering safety valve. The lifting reversing valve plate is composed of a one-way valve, a lifting reversing valve, a hydraulic control one-way valve and a main safety valve. The tilting reversing valve plate comprises a tilting reversing valve and a tilting one-way valve. The fitting reversing valve plate comprises a fitting reversing valve and a fitting one-way valve. The lifting reversing valve adopts a three-position eight-way reversing valve, dual-pump oil supplying only during lifting is achieved, and the large flow demand is met; portal-frame tilting and fitting acting which need smaller flow can be achieved through one-pump oil supplying, the pressure loss of the system is low, and the energy loss is low.

Description

technical field [0001] The invention belongs to the technical field of forklifts, and in particular relates to hydraulic systems of forklifts. Background technique [0002] At present, most domestic internal combustion forklifts above 4T use a quantitative pump dual-pump oil supply hydraulic system, that is, the flow required for the action of the working device is realized by simultaneous oil supply by dual pumps. The flow rate of the system is generally determined according to the maximum flow requirement required for the mast to lift, and when the mast is tilted or the attachment is moved, the required flow rate is only 30% of the maximum flow rate due to the movement speed requirements of the working cylinder ~50%, but the multi-way valve is in the confluence state. In order to adjust the movement speed of the tilt or the action of the attachment, a throttle valve is generally set in the multi-way valve or pipeline to control, and the excess flow passes through the throt...

AI Technical Summary

Problems solved by technology

The flow rate of the system is generally determined according to the maximum flow requirement required for the mast to lift, and when the mast is tilted or the attachment is moved, the required flow rate is only 30% of the maximum flow rate due to the movement speed requirements of the working cylinder ~50%, but the multi-way valve is in the confluence state. In order to adjust the movement speed of the tilt or the action of the attachment, a throttle valve is generally set in the multi-way valve or pipeline to control, and the excess flow passes through the throttle valve and the overflow valve The high pressure overflows back into the hydraulic oil tank, resulting in a large energy loss, causing the system to heat up and affecting the normal operation of the system

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