CN-115853846-B - Lifting hydraulic system and loader

CN115853846BCN 115853846 BCN115853846 BCN 115853846BCN-115853846-B

Abstract

The invention relates to a load holding valve, which aims to solve the problem that a load holding protection function and a hydraulic damping module cannot be compatible in the existing lifting hydraulic system; the load maintaining valve comprises a cone valve, a load maintaining control electromagnetic valve and a damping hole, wherein the control end of the load maintaining control electromagnetic valve is electrically connected with the controller, the oil inlet and outlet ends of the cone valve are respectively communicated with a lifting oil cylinder control valve large cavity interface and a lifting oil cylinder large cavity, the hydraulic control end of the cone valve is communicated with the load port through the damping hole and is connected with the T port through the load maintaining control electromagnetic valve, and the controller correspondingly controls the load maintaining control electromagnetic valve to be in a cut-off state and a conduction state according to whether the pressure of the lifting oil cylinder control valve large cavity interface is smaller than a preset value or not. The invention can realize the coexistence of the movable arm damping function and the load holding function on the loader at the same time.

Inventors

Hua Longxin
FAN WUDE
LI ZEHUA
WANG YUN
LI DAYOU
LUO WEIFENG

Assignees

广西柳工机械股份有限公司

Dates

Publication Date: 20260505
Application Date: 20221205

Claims (9)

1. The lifting hydraulic system comprises a hydraulic oil tank, a hydraulic pump, a lifting oil cylinder control valve, a lifting oil cylinder and a hydraulic damping module, wherein an oil suction port of the hydraulic pump is connected with the hydraulic oil tank, an oil inlet of the lifting oil cylinder control valve is communicated with the pump port of the hydraulic pump, and a large cavity interface and a small cavity interface of the lifting oil cylinder control valve are connected with the hydraulic damping module; The load maintaining valve is provided with a P port communicated with a large cavity interface of the control valve of the lifting oil cylinder, a T port communicated with the hydraulic oil tank, a load port communicated with the large cavity of the lifting oil cylinder, a load maintaining control electromagnetic valve and a damping hole, wherein the load maintaining control electromagnetic valve and the damping hole are arranged in the load maintaining valve, and the control end of the load maintaining electromagnetic valve is electrically connected with the controller; The controller controls the load maintaining control electromagnetic valve to be in a cut-off state when the pressure of the large cavity interface of the lifting oil cylinder control valve is smaller than a preset value, and controls the load maintaining control electromagnetic valve to be in a conduction state when the pressure of the large cavity interface of the lifting oil cylinder control valve is larger than the preset value; The hydraulic damping module comprises an energy accumulator and a damping control valve, wherein the damping control valve is provided with an X2 port communicated with the energy accumulator, a T3 port communicated with a hydraulic oil tank, a HEAD port communicated with a large cavity interface of a lifting oil cylinder control valve, an ROD port communicated with a small cavity interface of the lifting oil cylinder control valve and comprises a damping valve, and an electric control end of the damping control valve is electrically connected with a controller; The damping valve is provided with a b port communicated with an X2 port, a c port communicated with a HEAD port, an e port communicated with a ROD port and a d port communicated with a T3 port, wherein the b port, the c port, the d port and the e port are mutually blocked when the damping valve is in a normal state; The damping control electromagnetic valve is a two-position three-way valve, and is provided with an f port communicated with a hydraulic control end of the damping valve, a g port communicated with a T3 port and an h port communicated with an X2 port, wherein the damping valve is in a normal position when one of the f ports is communicated with the g port or the h port and the f port is communicated with the g port, and the damping valve is in a damping position when the f port is communicated with the h port.
2. The lift hydraulic system of claim 1, wherein the load holding valve further comprises an overload valve having an oil inlet and outlet port in communication with the load port and the T port, respectively.
3. The lift hydraulic system of claim 1, wherein the system further comprises a shock absorbing enabling operation device; The damping enabling operation device is connected with the controller and used for sending damping opening and damping closing signals to the controller, when the controller receives the damping opening signals, the controller controls the damping control electromagnetic valve to conduct an f port and an h port, and when the controller receives the damping closing signals, the controller controls the damping control electromagnetic valve to conduct the f port and the g port.
4. The lifting hydraulic system according to claim 3, wherein the damping control valve further comprises a port P3 connected with a pump port of the hydraulic pump, a filling valve and a check valve, the damping valve further comprises a port a connected with an oil outlet end of the check valve, an oil inlet end of the check valve is connected with the oil outlet end of the filling valve, the oil inlet end of the filling valve is communicated with the port P3, the port a and the port b are communicated when the damping valve is in a normal state, and the port a is blocked when the damping valve is in a damping position.
5. The lift hydraulic system of claim 4, further comprising an accumulator pressure sensor coupled to the controller for detecting accumulator pressure, the controller controlling the shock control solenoid valve to conduct port f and port g when accumulator pressure is less than a predetermined pressure value.
6. The lifting hydraulic system according to claim 5, further comprising a load feedback electromagnetic switch valve with a control end electrically connected with the controller, wherein the hydraulic pump is a variable pump, and two oil ports of the load feedback electromagnetic switch valve are respectively communicated with an LS port and a P3 port of the hydraulic pump.
7. The lifting hydraulic system of claim 4, wherein the damping control valve further comprises a liquid filling overflow valve, a throttle valve and a second damping hole, wherein the oil inlet end of the one-way valve is communicated with the oil outlet end of the liquid filling valve through the throttle valve, the oil inlet end of the one-way valve is simultaneously communicated with the oil inlet end of the liquid filling overflow valve and a spring cavity at the left end of a valve rod of the liquid filling valve through the second damping hole, the oil outlet end of the liquid filling overflow valve is communicated with a T3 port, the right end hydraulic control cavity of the valve rod of the liquid filling valve is communicated with the oil inlet end, the oil inlet end and the oil outlet end are cut off when the liquid filling valve is at a left position, and the oil inlet end and the oil outlet end are communicated when the liquid filling valve is at a right position through a third damping hole on the valve rod.
8. The lift hydraulic system of claim 4, wherein the shock absorbing control valve further comprises a relief valve having an oil inlet port in communication with port X2 and an oil outlet port in communication with port T3.
9. A loader, characterized in that it comprises a lifting hydraulic system according to any one of claims 1 to 8, the lifting cylinder being a boom cylinder.

Description

Lifting hydraulic system and loader Technical Field The present invention relates to a load holding valve, and more particularly, to a lifting hydraulic system and a loader. Background The load holding valve is typically mounted on a lift cylinder of the lift device, such as a boom cylinder in a loader arm lift hydraulic system. As shown in fig. 1, in the loader arm lifting hydraulic system, a hydraulic pump 2 sucks oil from a hydraulic tank 1 and supplies the oil to a distribution valve 3, an A1 port of a boom link of the distribution valve 3 is connected to a large chamber of a boom cylinder 4 through a pilot-operated load holding valve 5, and a B1 port is connected to a small chamber of the boom cylinder. When the hydraulic hose assembly between the A1 port of the movable arm link and the load holding valve 5 bursts, the load holding valve 5 acts to lock the hydraulic oil in the large cavity 4 of the movable arm oil cylinder, so that the materials and the whole machine are protected from being damaged. In the prior art, some loaders are equipped with a hydraulic damping module, and as shown in fig. 1, the A1 port and the B1 port of the boom link of the distribution valve 3 are simultaneously connected to the damping control valve 7 in the hydraulic damping module. When the movable arm damping function is started, the working device jolts up and down during the whole machine work, hydraulic oil in a large cavity of the movable arm oil cylinder 4 can enter the energy accumulator 6 through the damping control valve 7, and hydraulic oil fluctuation caused by jolts up and down can be absorbed through the energy accumulator 6, so that the function of damping vibration is achieved for the working device. In the prior art, when the movable arm vibration reduction function is independently used, leakage exists in a valve rod in the vibration reduction process, hydraulic oil of the energy accumulator is reduced after a period of time, the vibration reduction effect is reduced until the energy accumulator fails, and at the moment, the pump cannot automatically charge the energy accumulator for energy storage. The existing load holding valve 4 cannot be compatible with a hydraulic damping module, when the loader is in a transportation working condition, the working device jolts up and down, when the movable arm damping function is automatically started, pressure oil of the energy accumulator 6 enters the load holding valve 5 through the damping control valve 7 and enters a large cavity of the movable arm oil cylinder 4, hydraulic oil in the large cavity of the movable arm oil cylinder 4 cannot enter the damping control valve 7 through the load holding valve 5, so that pressure fluctuation caused by the jolts up and down of the working device cannot be filtered, the movable arm damping effect cannot be achieved, and the movable arm damping function cannot coexist with the load holding valve function. Disclosure of Invention The invention aims to solve the technical problem that a load maintaining protection function and a hydraulic damping module in the existing lifting hydraulic system cannot be compatible, and provides a lifting hydraulic system and a loader so as to realize damping and descending locking of a movable arm on the loader at the same time. The technical scheme for achieving the purpose is that the lifting hydraulic system comprises a hydraulic oil tank, a hydraulic pump, a lifting oil cylinder control valve, a lifting oil cylinder and a hydraulic damping module, wherein an oil suction port of the hydraulic pump is connected with the hydraulic oil tank, an oil inlet of the lifting oil cylinder control valve is communicated with the pump port of the hydraulic pump, a large cavity interface and a small cavity interface of the lifting oil cylinder control valve are connected with the hydraulic damping module, and the lifting oil cylinder control valve small cavity interface is communicated with a small cavity of the lifting oil cylinder; The load maintaining valve is provided with a P port communicated with a large cavity interface of the control valve of the lifting oil cylinder, a T port communicated with the hydraulic oil tank, a load port communicated with the large cavity of the lifting oil cylinder, a load maintaining control electromagnetic valve and a damping hole, wherein the load maintaining control electromagnetic valve and the damping hole are arranged in the load maintaining valve, and the control end of the load maintaining electromagnetic valve is electrically connected with the controller; The controller controls the load maintaining control electromagnetic valve to be in a cut-off state when the pressure of the large cavity interface of the lifting oil cylinder control valve is smaller than a preset value, and controls the load maintaining control electromagnetic valve to be in a conduction state when the pressure of the large cavity interface of the lifting oil cylinder control valve is