CN-121976586-A - Loader hydraulic system and loader

CN121976586ACN 121976586 ACN121976586 ACN 121976586ACN-121976586-A

Abstract

The invention discloses a hydraulic system of a loader and the loader, wherein the system comprises a steering pump, a working pump and a confluence switching valve for distributing the output flow of the steering pump and the working pump, an outlet of the steering pump is connected with an inlet of a priority valve, an outlet of the priority valve is connected with an inlet of a steering device, an outlet of the priority valve is connected with an inlet of the confluence switching valve, a working port of the steering device is connected with a steering cylinder, an outlet of the working pump is connected with an inlet of the confluence switching valve, an outlet of the confluence switching valve is connected with an inlet of a multi-way valve, and a working port of the multi-way valve is connected with the working cylinder. The invention can reduce the requirement of the power system on the total flow, reduce the pressure loss generated by different loads during the compound action and realize energy conservation.

Inventors

SUN ZHIYUAN
WEI CHAO
Wang Zongfan
GUO WENMING
ZHANG ANMIN
Shan Pengpeng
ZHANG JINGXIAN
QIAO ZHANZHAN
ZHAO MEI
SONG JIA
WANG KANG

Assignees

徐工集团工程机械股份有限公司科技分公司

Dates

Publication Date: 20260505
Application Date: 20260115

Claims (9)

1. A hydraulic system of a loader is characterized by comprising a steering pump (1), a working pump (2) and a converging switching valve (6) for distributing the output flow of the steering pump (1) and the output flow of the working pump (2), wherein an outlet of the steering pump (1) is connected with an inlet of a priority valve (4), an outlet of the priority valve (4) is connected with an inlet of a steering gear (5), an outlet of the priority valve is connected with an inlet of the converging switching valve (6), a working port of the steering gear (5) is connected with a steering cylinder, an outlet of the working pump (2) is connected with an inlet of the converging switching valve (6), an outlet of the converging switching valve (6) is connected with an inlet of a multi-way valve (7), and a working port of the multi-way valve (7) is connected with the working cylinder.
2. The loader hydraulic system of claim 1, wherein, The control port of the steering pump (1) is connected with the control port II of the priority valve (4); The control port of the working pump (2) is connected with the control port II of the confluence switching valve (6) and the control port of the multi-way valve (7); The control port III of the priority valve (4) is connected with the control port of the confluence switching valve (6), and the control port I of the priority valve (4) is connected with the control port of the steering gear (5); An inlet of the pilot oil source valve (3) is connected with a second control port of the multi-way valve (7), and an outlet of the pilot oil source valve (3) is connected with a third control port of the multi-way valve (7); The oil return port of the priority valve (4), the oil return port of the pilot oil source valve (3) and the oil return port of the confluence switching valve (6) are connected with the oil tank (8).
3. The loader hydraulic system according to claim 2, wherein the confluence switching valve is provided with a return spring, and the return spring control pressure p1 satisfies the following condition: p1<p3; Wherein p3 is the working pump control pressure.
4. The loader hydraulic system according to claim 2, wherein the steering pump control pressure p2 satisfies the following condition: p4<p2; Where p4 is the priority valve spring control pressure.
5. The loader hydraulic system of claim 2, wherein the work pump control pressure p3 satisfies the following condition: ; Wherein n is the engine speed, V1 is the steering pump displacement, V2 is the working pump displacement, C d is the fluid flow coefficient, A is the maximum area of the lifting valve core of the movable arm, and ρ is the hydraulic oil density.
6. The hydraulic system of the loader according to claim 2, wherein when the steering cylinder and the working cylinder are not operated, hydraulic oil output by the working pump (2) acts on a non-spring cavity of the confluence switching valve (6), the confluence switching valve (6) is driven to be in a diversion position, an inlet I of the confluence switching valve (6) is not communicated with an outlet of the confluence switching valve (6), a control port I of the confluence switching valve (6) is communicated with an oil return port of the confluence switching valve (6), and the pressure of the control port of the steering pump (1) is relieved through a control port II of the priority valve (4), a control port III of the priority valve (4), a control port I of the confluence switching valve (6) and an oil return port of the confluence switching valve (6), and at this time, the steering pump (1) is not affected by the working pump (2).
7. The hydraulic system of the loader according to claim 6, wherein when the steering cylinder is not operated and the working cylinder is operated, as the valve port of the multiple-way valve (7) is gradually opened, the displacement of the working pump (2) is gradually increased, since the working pump control pressure p3 is larger than the confluence switching valve return spring control pressure p1, the confluence switching valve (6) is at the split position, at this time, the steering pump (1) is in the low-pressure minimum displacement state, when the valve port of the multiple-way valve (7) is gradually opened until the working pump (2) reaches the maximum displacement, at this time, in the under-flow state, the pressure difference between the working pump outlet pressure and the working pump control outlet pressure is gradually decreased, when the pressure difference is smaller than p1, the control port one of the confluence switching valve (6) is communicated with the control port two, the displacement of the steering pump (1) is gradually increased, and when the working system reaches the system pressure, the pressure difference between the working pump outlet pressure and the working pump control outlet pressure is equal to p3, the working pump (2) becomes the minimum displacement operation, and since the pressure p3 p1 is at this time, the switching valve (6) is again at the split position, at the low displacement, the steering pump (1) is controlled.
8. The hydraulic system of the loader according to claim 6, wherein when the steering cylinder and the working cylinder are operated simultaneously, as the multiple valve ports are opened gradually, the displacement of the working pump (2) is increased gradually, and because the working pump (2) controls the pressure p3> p1, the confluence switching valve (6) is still in the diversion position in the flow saturation state, the steering pump (1) supplies oil to the steering system alone without being affected by the working load, when the multiple valve ports are opened gradually until the working pump (2) reaches the maximum displacement, and in the under-flow state, the pressure difference between the outlet of the working pump (2) and the control port of the working pump (2) is reduced gradually, and when the pressure difference is smaller than p1, the confluence switching valve (6) is in the confluence position, and the control port one and the control port two of the confluence switching valve (6) are communicated, and the steering pump (1) supplies oil to the steering system and the working system simultaneously.
9. A loader, characterized in that the loader is provided with a loader hydraulic system according to any one of claims 1-8.

Description

Loader hydraulic system and loader Technical Field The invention belongs to the technical field of loaders, and particularly relates to a loader hydraulic system and a loader. Background In the prior art, a loader load sensitive hydraulic system mainly has two technical routes, namely, a diversion system is adopted, namely, a steering pump is used for supplying steering flow, a working pump is used for supplying working flow, the energy consumption is lower under the avoided composite working condition, but in order to ensure the working flow requirement, the displacement of the working pump is large, the cost is high, the requirement on the whole power system is higher, and a confluence system is adopted, namely, the steering pump is used for simultaneously working and steering, and the working pump is independently used for working, so that the total flow of the system is greatly reduced, the requirement of the power system is reduced, and more energy loss is caused due to the existence of the steering and working composite working condition. Disclosure of Invention In order to solve the defects in the prior art, the invention provides the hydraulic system of the loader and the loader, which can reduce the requirement of a power system on the total flow, reduce the pressure loss generated by different loads during the compound action and realize energy conservation. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The hydraulic system of the loader comprises a steering pump, a working pump and a confluence switching valve used for distributing the output flow of the steering pump and the output flow of the working pump, wherein an outlet of the steering pump is connected with an inlet of a priority valve, an outlet of the priority valve is connected with an inlet of a steering device, an outlet of the priority valve is connected with an inlet of the confluence switching valve, a working port of the steering device is connected with a steering oil cylinder, an outlet of the working pump is connected with an inlet of the confluence switching valve, an outlet of the confluence switching valve is connected with an inlet of a multi-way valve, and a working port of the multi-way valve is connected with the working oil cylinder. The control port of the steering pump is connected with a control port II of the priority pump, the control port of the working pump is connected with a control port II of the confluence switching valve and a control port I of the multi-way valve, a control port III of the priority pump is connected with a control port I of the confluence switching valve, a control port I of the priority pump is connected with a control port II of the steering device, an inlet of the pilot oil source valve is connected with a control port II of the multi-way valve, an outlet of the pilot oil source valve is connected with a control port III of the multi-way valve, and an oil return port of the priority valve, an oil return port of the pilot oil source valve and an oil return port of the confluence switching valve are connected with an oil tank. Further, the confluence switching valve is provided with a return spring, and the return spring control pressure p1 satisfies the following condition: p1<p3; Wherein p3 is the working pump control pressure. Further, the steering pump control pressure p2 satisfies the following condition: p4<p2; Where p4 is the priority valve spring control pressure. Further, the working pump control pressure p3 satisfies the following condition: ; Wherein n is the engine speed, V1 is the steering pump displacement, V2 is the working pump displacement, C d is the fluid flow coefficient, A is the maximum area of the lifting valve core of the movable arm, and ρ is the hydraulic oil density. Further, when the steering oil cylinder and the working oil cylinder do not act, hydraulic oil output by the working pump acts on a non-spring cavity of the confluence switching valve to drive the confluence switching valve to be in a diversion position, an inlet I of the confluence switching valve is not communicated with an outlet of the confluence switching valve, a control port I of the confluence switching valve is communicated with an oil return port of the confluence switching valve, pressure of a control port of the steering pump is relieved through a control port II of the priority valve, a control port III of the priority valve, a control port I of the confluence switching valve and the oil return port of the confluence switching valve, and at the moment, the steering pump is not influenced by the working pump. Further, when the steering cylinder does not act and the working cylinder acts, as the valve port of the multi-way valve is gradually opened, the displacement of the working pump is gradually increased, and as the control pressure p3 of the working pump is larger than the control pressure p1 of the return spring of the converging