A loader hydraulic system and a loader

Abstract

The application discloses a loader hydraulic system and a loader in the technical field of loaders. A variable pump inputs hydraulic oil into a steering hydraulic cylinder through a priority valve and a steering gear, and is used for controlling the steering of the loader. The variable pump inputs hydraulic oil into a first executing element and a second executing element through the priority valve and an energy-saving multi-way valve, and is used for controlling the first executing element and the second executing element to complete a single action or a composite action. An LS2 port of the energy-saving multi-way valve is connected with an LS3 port of the priority valve, and is used for controlling the steering hydraulic cylinder, the first executing element and the second executing element to complete the single action or the composite action. The combined composite action of the steering, a boom and a bucket of the loader can be realized, the variable effect of the variable pump is fully exerted, and energy saving is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of loaders, and particularly relates to a loader hydraulic system and a loader. BACKGROUND

[0002] As a shovel mechanical device, a loader is an engineering machine pursuing efficiency. Shovel digging and loading of the loader are realized through a loader hydraulic system, and need combined composite actions of steering, a boom, and a dump body. The hydraulic system generally mainly comprises a working hydraulic system and a steering hydraulic system.

[0003] A constant hydraulic system can realize separate control of the working hydraulic system and the steering hydraulic system, but the hydraulic system is low in efficiency, and cannot realize combined composite actions of steering, a dump body, and a boom, and has a large by-pass throttling loss. A variable hydraulic system realizes the combination of steering and a dump body (a boom), but cannot realize the combination of the three or the combination of a boom and a dump body due to the use of an open-center multi-way valve, and when the working device has an action, the variable pump is in a constant state and outputs full displacement, and cannot play the regulating role of the variable pump according to system requirements, and the energy-saving effect is poor. SUMMARY

[0004] To solve the problems in the prior art, the present application provides a loader hydraulic system and a loader, which can realize combined composite actions of steering, a boom, and a dump body of the loader, fully play the variable effect of the variable pump, and realize energy saving.

[0005] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, a loader hydraulic system is provided, comprising: a variable pump, a priority valve, a diverter, and an energy-saving multi-way valve; the variable pump inputs hydraulic oil into a steering hydraulic cylinder through the priority valve and the diverter, and is used for controlling steering of the loader; the variable pump inputs hydraulic oil into first and second executing elements through the priority valve and the energy-saving multi-way valve, and is used for controlling the first and second executing elements to complete single or composite actions; an LS2 port of the energy-saving multi-way valve is connected with an LS3 port of the priority valve, and is used for controlling the steering hydraulic cylinder, the first executing element, and the second executing element to complete single or composite actions.

[0007] Further, the energy-saving multi-way valve comprises: a first main valve core for controlling the communication or shutoff of input oil ports P1 and P2 and output oil ports A1 and B1; a second main valve core for controlling the communication or shutoff of input oil ports P1 and P2 and output oil ports A2 and B2; when the first main valve core and the second main valve core are not in action, input oil ports P1 and P2 are separated from output oil ports A1 and B1 by the first main valve core (51); input oil ports P1 and P2 are separated from output oil ports A2 and B2 by the second main valve core; when the first main valve core is in action, hydraulic oil input from input oil ports P1 and P2 enters the first bypass through a sixth one-way valve; the first bypass realizes the communication or shutoff between output oil ports A1 and B1 through the first main valve core and is fed back to an LS oil port through a fifth one-way valve; when the second main valve core is in action, hydraulic oil input from input oil ports P1 and P2 enters the second bypass through a third one-way valve; the second bypass realizes the communication or shutoff between output oil ports A2 and B2 through the second main valve core and is fed back to the LS oil port through a fourth one-way valve.

[0008] Further, the energy-saving multi-way valve further comprises control oil ports a1, a2, b1 and b2; control oil port a1 is in communication with the right cavity end of the first main valve core and is used for controlling the first main valve core to move left to the right position; control oil port b1 is in communication with the left cavity end of the first main valve core and is used for controlling the first main valve core to move right to the left position; control oil port a2 is in communication with the right cavity end of the second main valve core and is used for controlling the second main valve core to move left to the right position; control oil port b2 is in communication with the left cavity end of the second main valve core and is used for controlling the second main valve core to move right to the left one position or the left two position; control oil port a1 is in communication with the oil inlet of the reversing valve core through a first damping, and the oil inlet of the reversing valve core is in communication with the right cavity end of the first main valve core, and the oil outlet of the reversing valve core is in communication with the T port through a second damping; control oil port a2 is in communication with the right control end of the reversing valve core, and the left control end of the reversing valve core is controlled by a spring and is in communication with the T port.

[0009] Further, output oil port B1 is in communication with output oil port B2 through a first one-way valve and a second one-way valve and is used for supplementing oil to the rod cavity of the first actuating element and the second actuating element.

[0010] Further, a pilot oil source valve is further included, the oil inlet of the pilot oil source valve is in communication with the Mp port of the energy-saving multi-way valve, the oil outlet of the pilot oil source valve is connected with a two-way ball valve and a pilot valve in sequence, and the pilot valve is used for controlling the first main valve core and the second main valve core through control oil ports a1, a2, b1 and b2.

[0011] Further, the composite action comprises: rotating the two-way ball valve to switch the two-way ball valve from the first working position to the second working position, controlling the control oil port a1 and a2 of the energy-saving multi-way valve through the pilot valve to make the first main valve core and the second main valve core move to the left; realizing displacement matching of the first main valve core and the second main valve core according to the pressure of the control oil port a2; when the pressure of the control oil port a2 is greater than the pressure set by the spring, the reversing valve core is switched from the first working position to the second working position, at this time, the pressure of the control oil port a1 is reduced through the first damping, the reversing valve core and the second damping, so that the pressure of the right cavity end of the first main valve core is reduced to control the position change of the first main valve core; according to the pressure of the control oil port a2, the pressure reaching the control end of the right side of the first main valve core is adjusted to form displacement matching of the first main valve core and the second main valve core.

[0012] Further, the composite action further comprises: the first main valve core and the second main valve core are both reversed to the right position, the oil inlet of the first main valve core passes through the sixth one-way valve to the throttle port of the first main valve core and is communicated with the output oil port A1; the fifth one-way valve is communicated with the LS2 port, so that the load pressure signal of the first actuator is fed back to the LS2 port; the oil inlet of the second main valve core passes through the third one-way valve to the throttle port of the second main valve core and is communicated with the output oil port A2; the fourth one-way valve is communicated with the LS2 port, so that the load pressure signal of the second actuator is fed back to the LS2 port, after comparison of the two load feedback pressures, the higher pressure is transmitted to the LS2 port, and the lower pressure is cut off due to the one-way valve; realizing that the variable pump provides flow according to the opening demand of the first main valve core and the second main valve core.

[0013] Further, the composite action further comprises: the first main valve core moves to the left to a certain distance, at this time, the output oil port A1 is communicated with the first bypass through the first main valve core, and the output oil port B1 is communicated with the T port through the first main valve core; the input oil port P1 enters the first bypass through the first main valve core and the sixth one-way valve; the first bypass is communicated with the LS2 port through the fifth one-way valve; the second main valve core moves to the left to a certain distance, at this time, the output oil port A2 is communicated with the second bypass through the second main valve core, and the output oil port B2 is communicated with the T port through the second main valve core; the input oil port P1 enters the second bypass through the second main valve core and the third one-way valve, and the second bypass is communicated with the LS2 port through the fourth one-way valve, compared with each other, the one with higher pressure is communicated with the LS2 port, and the one with lower pressure is reversely cut off due to the one-way valve.

[0014] In the second aspect, a loader is provided, and the loader is configured with the loader hydraulic system in the first aspect.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] (1) the variable pump of the present application inputs hydraulic oil into the steering hydraulic cylinder through the priority valve and the steering gear, which is used to control the steering of the loader; the variable pump inputs hydraulic oil into the first and second execution elements through the priority valve and the energy-saving multi-way valve, which is used to control the first and second execution elements to complete single or composite action; the LS2 port of the energy-saving multi-way valve is connected with the LS3 port of the priority valve, which is used to control the steering hydraulic cylinder, the first and second execution elements to complete single or composite action; the combined composite action of the steering, the boom and the dump body of the loader can be realized, the variable effect of the variable pump is fully exerted, and energy saving is realized;

[0017] (2) the inlet one-way valve structure is adopted to replace the original pressure compensator structure, the pilot compensation valve core is used, the displacement of the valve core at different positions is realized, and thus the composite action is realized.

[0018] (3) the variable pump of the present application participates in variable regulation throughout the whole process, the combined composite action of the steering, the boom and the dump body of the loader is realized, the variable effect of the variable pump is fully exerted, and energy saving is realized. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the hydraulic principle diagram of the energy-saving multi-way valve in the embodiment of the present application;

[0020] Figure 2 is the first perspective structural schematic diagram of the energy-saving multi-way valve in the embodiment of the present application;

[0021] Figure 3 is the structural schematic diagram of the center section of the energy-saving multi-way valve in the embodiment of the present application;

[0022] Figure 4 is the structural schematic diagram of the energy-saving multi-way valve in the embodiment of the present application, which is the bottom view of Figure 2 ;

[0023] Figure 5 is the sectional view schematic diagram of the first main valve core of the energy-saving multi-way valve in the embodiment of the present application;

[0024] Figure 6 is the sectional view schematic diagram of the second main valve core of the energy-saving multi-way valve in the embodiment of the present application;

[0025] Figure 7 is the sectional view schematic diagram of the fourth one-way valve and the sixth one-way valve of the energy-saving multi-way valve in the embodiment of the present application;

[0026] Figure 8 is the sectional view schematic diagram of the reversing valve core of the energy-saving multi-way valve in the embodiment of the present application;

[0027] Figure 9 is the hydraulic system principle diagram of the energy-saving multi-way valve as the embodiment in the embodiment of the present application;

[0028] In the figure: 1. Variable pump; 2. Steering gear; 3. Steering hydraulic cylinder; 4. Priority valve; 5. Pilot oil source valve; 6. First actuator; 7. Second actuator; 8. Energy-saving multi-way valve; 9. Return oil filter; 10. Radiator; 11. Hydraulic oil tank; 12. Two-way ball valve; 13. Pilot valve; 51. First main valve core; 52. Second main valve core; 53. Main safety valve; 54. LS relief valve; 55. Constant flow valve; 56. First overload valve; 57. First one-way valve; 58. Second overload valve; 59. Second one-way valve; 60. Third one-way valve; 61. Fourth one-way valve; 62. Fifth one-way valve; 63. Sixth one-way valve; 64. Reversing valve core; 65. Spring; 66. First damper; 67. Second damper; 68. Third damper DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0030] Example 1:

[0031] like Figures 1-9 As shown, a loader hydraulic system includes: a variable pump 1, a priority valve 4, a steering gear 2 and an energy-saving multi-way valve 8; the variable pump 1 inputs hydraulic oil into the steering hydraulic cylinder 3 through the priority valve 4 and the steering gear 2 to control the steering of the loader; the variable pump 1 inputs hydraulic oil into the first actuator 6 and the second actuator 7 through the priority valve 4 and the energy-saving multi-way valve 8 to control the first actuator 6 and the second actuator 7 to complete a single action or a compound action; the LS2 port of the energy-saving multi-way valve 8 is connected to the LS3 port of the priority valve 4 to control the steering hydraulic cylinder 3, the first actuator 6, and the second actuator 7 to complete a single action or a compound action.

[0032] like Figure 1 As shown, the energy-saving multi-way valve 8 is composed of P1 port, P2 port, MP port, LS port, LS2 port, T port, a1 port, a2 port, b1 port, b2 port, A1 port, A2 port, B1 port, B2 port, A2', and B2'.

[0033] The energy-saving multi-way valve 8 includes a first main valve core 51 with three positions and closed center, a second main valve core 52 with four positions and closed center, a main safety valve 53, an LS relief valve 54, a constant flow valve 55, a first overload valve 56, a first check valve 57, a second overload valve 58, a second check valve 59, a third check valve 60, a fourth check valve 61, a fifth check valve 62, a sixth check valve 63, a reversing valve core 64, a spring 65, a first damper 66, a second damper 67, and a third damper 68.

[0034] The three functional positions of the first main valve core 51 are left position, middle position and right position. When in the middle position, the oil inlet is cut off, and the pressure oil for driving the first actuator 6 cannot be output through the first main valve core 51. The first actuator 6 is the tipping cylinder of the loader. The small cavity B1 port of the first actuator 6 is communicated with the oil outlet of the first check valve 57, the oil inlet of the first check valve 57 is communicated with the T port, which is used for oil supplement of the small cavity of the first actuator 6 to prevent air suction. The small cavity B1 port of the first actuator 6 is communicated with the oil inlet of the first overload valve 56, the oil outlet of the first overload valve 56 is communicated with the T port, which is used for overload protection of the small cavity B1 port of the first actuator 6. The large cavity A1 port of the first actuator 6 is communicated with the oil inlet of the second overload valve 58, the oil outlet of the second overload valve 58 is communicated with the T port, which is used for overload protection of the large cavity A1 port of the first actuator 6.

[0035] The four functional positions of the second main valve core 52 are left two position, left one position, middle position and right position. When in the middle position, the oil inlet is cut off, and the pressure oil for driving the second actuator 7 cannot be output through the second main valve core 52. The left two position simultaneously communicates the oil outlets A2 port and B2 port of the second main valve core 52 with the oil return T port. The second actuator 7 is the boom cylinder of the loader. The small cavity B2 port of the second actuator 7 is communicated with the oil outlet of the second check valve 59, the oil inlet of the second check valve 59 is communicated with the T port, which is used for oil supplement of the small cavity of the second actuator 7 to prevent air suction.

[0036] The P1 port is connected with the second working oil port EF port of the priority valve 4, the LS2 port is connected with the LS3 port of the priority valve 4, the LS1 port of the priority valve 4 is connected with the LS port of the steering gear 2, the LS2 port of the priority valve 4 is connected with the X port of the variable pump 1, and the pressure of the LS2 port of the priority valve 4 is fed back to the variable pump 1 after comparing the steering load signal and the working load signal, so that the variable pump 1 provides pressure oil according to the load demand.

[0037] The control oil port a1 is communicated with the 3 port of the pilot valve 13, which is used for controlling the first main valve core 51 to move left to the right position. The control oil port b1 is communicated with the 2 port of the pilot valve 13, which is used for controlling the second main valve core 52 to move right to the left position.

[0038] The control oil port a2 is communicated with the 4 port of the pilot valve 13, which is used for controlling the second main valve core 52 to move left to the right position. The control oil port b2 is communicated with the 1 port of the pilot valve 13, which is used for controlling the second main valve core 52 to move right to the left one position or the left two position.

[0039] The hydraulic oil in the T port flows into the hydraulic oil tank 11 through the radiator 10 and the oil return filter 9, which is used for hydraulic system oil return.

[0040] The A1 port and the B1 port are connected with the tipping cylinder of the first actuator 6, which is used for outputting flow to the tipping cylinder of the first actuator 6.

[0041] A2 port, B2 port and the boom cylinder size cavity of the second actuator 7 are connected, for output flow to the boom cylinder of the second actuator 7.

[0042] Mp port and P1 port are communicated through oil channel, Mp port is connected with P port of the pilot oil source valve 5, A port of the pilot oil source valve 5 is communicated with the inlet of the two-way ball valve 12, the outlet of the two-way ball valve 12 is communicated with the inlet P port of the pilot valve 13. The two-way ball valve 12 is used to cut off the oil circuit of the pilot valve 13 to prevent misoperation.

[0043] When the first main valve core 51 is in the middle position, the inlet of the first main valve core 51 is in the cut-off state, when the first main valve core 51 is reversed, the inlet of the first main valve core 51 passes through the left or right oil circuit of the first main valve core 51, through the sixth one-way valve 63, to the throttle port of the first main valve core 51, and outputs from the outlet A1 port or B1 port, to supply oil to the first actuator 6, and the return oil of the first actuator 6 returns through the other outlet port through the first main valve core 51.

[0044] When the second main valve core 52 is in the middle position, the inlet of the second main valve core 52 is in the cut-off state, when the second main valve core 52 is reversed, the inlet of the second main valve core 52 passes through the right or left oil circuit of the second main valve core 52, through the third one-way valve 60, to the throttle port of the second main valve core 52, and outputs from the outlet A2 port or B2 port, to supply oil to the second actuator 7, and the return oil of the second actuator 7 returns through the other outlet port through the second main valve core 52. When the second main valve core 52 is reversed to the left second position, the inlet of the second main valve core 52 passes through the third one-way valve 60 and returns to the second main valve core 52 and the return oil T port, the oil ports A2 port and B2 port are simultaneously communicated with the return oil T port through the left second position of the second main valve core 52, and the second actuator 7 is in a floating state.

[0045] The feedback port of the first main valve core 51 is communicated with the feedback port of the second main valve core 52 through the fifth one-way valve 62 and the fourth feedback one-way valve 61, and the LS port of the energy-saving multi-way valve 8 or the LS2 port is communicated, the LS port is simultaneously communicated with the inlet of the constant flow valve 55, and the outlet of the constant flow valve 55 is communicated with the T port.

[0046] The LS2 port is communicated with the LS port through the third damper 68, the LS port is communicated with the inlet of the LS overflow valve 54, and the outlet of the LS overflow valve 54 is communicated with the T port.

[0047] The P1 port and the P2 port are connected with the inlet of the main safety valve 53, and the outlet of the main safety valve 53 is communicated with the T port.

[0048] The control oil port a1 is communicated with the 3 port of the pilot valve 13 and the right cavity end of the first main valve core 51, and is used for controlling the first main valve core 51 to move to the right position. The control oil port b1 is communicated with the 2 port of the pilot valve 13 and the left cavity end of the first main valve core 51, and is used for controlling the second main valve core 52 to move to the left position.

[0049] The control oil port a2 is communicated with the 4 port of the pilot valve 13 and the right cavity end of the second main valve core 52, and is used for controlling the second main valve core 52 to move to the right position. The control oil port b2 is communicated with the 1 port of the pilot valve 13 and the left cavity end of the second main valve core 52, and is used for controlling the second main valve core 52 to move to the left one position or the left two position.

[0050] The control oil port a1 is communicated with the oil inlet of the reversing valve 64 through the first damper 66, and the oil inlet of the reversing valve 64 is communicated with the right cavity end of the first main valve core 51, and the oil outlet of the reversing valve 64 is communicated with the T port of the energy-saving multi-way valve 8 through the second damper 67. The control oil port a2 is communicated with the right control end of the reversing valve 64, and the left side of the reversing valve is controlled by the spring to move the reversing valve 64, and is communicated with the T port.

[0051] When the control oil ports a1 and a2 have pressure oil at the same time, and the pressure of the a2 port is greater than the pressure set by the spring 65, the reversing valve 64 is switched from the first working position to the second working position, at this time, the pressure of the a1 port is reduced through the first damper 66, the reversing valve 64, and the second damper 67, so that the pressure of the right cavity end of the first main valve core 51 is reduced, and the position change of the first main valve core 51 is controlled. By adjusting the pressure of the a2 port, the pressure reaching the right control end of the first main valve core 51 is adjusted, the displacement matching of the first main valve core 51 and the second main valve core 52 is formed, and the composite action is realized.

[0052] The working principle of the hydraulic system in the embodiment is as follows:

[0053] 1. No operation action: the first main valve core 51 and the second main valve core 52 are both in the middle position. The LS2 feedback ports are disconnected from the oil inlets and outlets through the main valve cores, and the LS2 oil way is communicated with the T port through the constant flow valve 55, without load feedback pressure, so the variable pump 1 runs at the minimum displacement to maintain the standby pressure of the variable pump port.

[0054] Specifically, the P1 oil way and the P2 oil way of the energy-saving multi-way valve 8 are isolated from the T port through the first main valve core 51 and the second main valve core 52 to realize the closed core principle. The A1B1' oil way (the first bypass, Figure 1 The A2B2' oil way (the second bypass, between the first main valve core 51 and the second main valve core 52) is disconnected from the oil ports A1 and B1 through the first main valve core 51; and the A2B2' oil way (the second bypass, Figure 1In this case, the third one-way valve 60 is blocked between the second main spool 52 and the oil port A2, B2, and the second main spool 52 is blocked from the oil ports A2, B2, so that no load feedback pressure is fed back to the variable pump 1.

[0055] 2. Single action: taking the operation of the boom joint as an example, when the two-way ball valve 12 is manually rotated to switch the two-way ball valve 12 from the first working position to the second working position, the pilot valve 13 is actuated, so that the two ports of the pilot valve 13 output pressure to the b1 port of the energy-saving multi-way valve 8, so that the second main spool 52 is switched to the left first position, and the oil inlet of the second main spool 52 passes through the third one-way valve 60 to the throttle port of the second main spool 52 and is communicated with the B2 port; and the fourth one-way valve 61 is communicated with the LS2 port, so that the load pressure signal of the second actuator 7 is fed back to the LS2 port, and is fed back to the X port of the variable pump 1 through the LS3 port of the priority valve 4 and the LS2 port of the priority valve 4, so that the variable pump 1 provides flow according to the opening demand of the second main spool 52. When the load pressure of the second actuator 7 is higher than the set pressure of the LS relief valve 54, the LS relief valve 54 is opened, and the oil in the LS2 port flows back to the hydraulic oil tank 11 through the constant flow valve 55 and the LS relief valve 54 through the T port of the energy-saving multi-way valve 8.

[0056] Specifically: the second main spool 52 moves to the right to a certain distance, at this time the oil passage B2 is communicated with the oil passage A2B2' through the second main spool 52, and the oil passage A2 is communicated with the oil passage T through the second main spool 52. The P1 oil passage passes through the second main spool 52, enters the oil passage A2B2' through the third one-way valve 60. The oil passage A2B2' is communicated with the LS2 oil passage through the fourth one-way valve 61, so that the load signal is fed back to the X port of the variable pump 1.

[0057] Continue to push the pilot valve 13, so that the output pressure of the two ports of the pilot valve 13 continues to increase, and when it increases to the maximum output pressure of the two ports of the pilot valve 13, the second main spool 52 is switched to the left second position, and the A2 port and the B2 port of the second main spool 62 are simultaneously communicated with the return oil T through the second main spool 52 left second position, and the second actuator 7 is in a floating state. At this time, the LS port has no pressure feedback, and the variable pump 1 is in a standby pressure state.

[0058] Specifically: the second main spool 52 continues to move to the right to a certain distance, at this time the oil passage B2 is communicated with the oil passage A2B2' through the second main spool 52, the oil passage B2 is communicated with the oil passage T through the second main spool 52, and the oil passage A2 is communicated with the oil passage T through the second main spool 52, so that the oil ports A2, B2 and T are communicated with each other, and the floating state is realized.

[0059] 3. Composite action. When the two-way ball valve 12 is manually rotated to switch the two-way ball valve 12 from the first working position to the second working position, the pilot valve 13 is moved at the same time, and the 3rd and 4th ports of the pilot valve 13 have output pressure to the a1 end and a2 end of the energy-saving multi-way valve 8, so that the first main valve core 51 and the second main valve core 52 move to the left. According to the pressure of the a2 port end, the displacement matching of the first main valve core 51 and the second main valve core 52 is realized. When the a2 port pressure is greater than the pressure set by the spring 65, the reversing valve 64 is switched from the first working position to the second working position, and at this time the a1 port pressure is reduced through the first damping 66, the reversing valve 64 and the second damping 67, so that the pressure of the right cavity end of the first main valve core 51 is reduced, and the position change of the first main valve core 51 is controlled. According to the a2 port pressure, the pressure reaching the control end on the right side of the first main valve core 51 is adjusted to form the displacement matching of the first main valve core 51 and the second main valve core 52.

[0060] Since the first main valve core 51 and the second main valve core 52 are both switched to the right position, the oil inlet of the first main valve core 51 communicates with the a1 port through the sixth one-way valve 63 to the throttle port of the first main valve core 51, and communicates with the LS2 port through the fifth one-way valve 62, so as to feed back the load pressure signal of the first actuator 6 to the LS2 port; the oil inlet of the second main valve core 52 communicates with the a2 port through the third one-way valve 60 to the throttle port of the second main valve core 52, and communicates with the LS2 port through the fourth one-way valve 61, so as to feed back the load pressure signal of the second actuator 7 to the LS2 port. After comparison of the two load feedback pressures, the higher pressure is transmitted to the LS2 port, and the lower pressure is cut off due to the one-way valve. For example, the load pressure of the first actuator 6 is high, and the load feedback pressure is transmitted to the LS2 port through the fifth one-way valve 62, and the load pressure of the second actuator 7 is cut off at the fourth one-way valve 61. The pressure of the LS2 port is fed back to the X port of the variable pump 1 through the LS3 port of the priority valve 4 to the LS2 port of the priority valve 4, so as to realize the flow demand of the variable pump 1 according to the opening demand of the first main valve core 51 and the second main valve core 52.

[0061] Specifically: due to the pressure of the a2 end acting on the left end of the reversing valve core 64, the reversing valve core 64 moves to the right, the pressure of the a1 end communicates with the spring 65 cavity through the first damping 66 at the reversing valve 64, and the spring 65 cavity communicates with the T port through the second damping 67, so as to reduce the a1 cavity pressure. The displacement matching of the first main valve core 51 and the second main valve core 52 is realized.

[0062] That is, the first main valve core 51 moves left to a certain distance, at this time, the oil passage A1 and the oil passage A1B1' are communicated through the first main valve core 51, the oil passage B1 and the oil passage T are communicated through the first main valve core 51. The P1 oil passage passes through the first main valve core 51, passes through the sixth one-way valve 63 and enters the oil passage A1B1'. The oil passage A1B1' communicates with the LS2 oil passage through the fifth one-way valve 62; the second main valve core 52 moves left to a certain distance, at this time, the oil passage A2 and the oil passage A2B2' are communicated through the second main valve core 52, the oil passage B2 and the oil passage T are communicated through the second main valve core 52. The P1 oil passage passes through the second main valve core 52, enters the oil passage A2B2' through the third one-way valve 60. The oil passage A2B2' communicates with the LS2 oil passage through the fourth one-way valve 61. Compared with each other, the one with high pressure will be communicated with the oil passage LS2, and the one with low pressure will be reversely cut off due to the one-way valve.

[0063] Embodiment two:

[0064] Based on the loader hydraulic system described in embodiment one, the embodiment provides a loader, which is configured with the loader hydraulic system described in embodiment one, wherein the oil inlet P of the energy-saving multi-way valve 8 can be connected with the second working port EF of the priority valve 4, or can be directly connected with the oil outlet of the variable pump 1. The LS port is connected with the LS3 port of the priority valve 4, or can be directly connected with the X port of the variable pump 1. The T port and the L port are connected with the hydraulic oil tank 11.

[0065] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, without departing from the technical principles of the present application, several improvements and modifications can be made, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A loader hydraulic system, characterized in that: include: A variable pump (1), a priority valve (4), a steering gear (2) and an energy-saving multi-way valve (8); the variable pump (1) inputs hydraulic oil into the steering hydraulic cylinder (3) through the priority valve (4) and the steering gear (2) for controlling the steering of the loader; the variable pump (1) inputs hydraulic oil into the first actuator (6) and the second actuator (7) through the priority valve (4) and the energy-saving multi-way valve (8) for controlling the first actuator (6) and the second actuator (7) to complete a single action or a compound action; the LS2 port of the energy-saving multi-way valve (8) is connected to the LS3 port of the priority valve (4) for controlling the steering hydraulic cylinder (3), the first actuator (6) and the second actuator (7) to complete a single action or a compound action; The energy-saving multi-way valve (8) comprises: A first main valve core (51) for controlling the connection or disconnection between the input oil ports P1, P2 and the output oil ports A1, B1; A second main valve core (52) for controlling the connection or disconnection between the input oil ports P1, P2 and the output oil ports A2, B2; When the first main valve core (51) and the second main valve core (52) are not in motion, the input oil ports P1 and P2 are separated from the output oil ports A1 and B1 by the first main valve core (51); the input oil ports P1 and P2 are separated from the output oil ports A2 and B2 by the second main valve core (52); When the first main valve core (51) is activated, the hydraulic oil input from the input oil ports P1 and P2 enters the first bypass through the sixth one-way valve (63); the first bypass is connected and disconnected with the output oil ports A1 and B1 through the first main valve core (51), and is fed back to the LS oil port through the fifth one-way valve (62); When the second main valve core (52) is activated, the hydraulic oil input from the input oil ports P1 and P2 enters the second bypass through the third one-way valve (60); the second bypass is connected and disconnected with the output oil ports A2 and B2 through the second main valve core (52), and is fed back to the LS oil port through the fourth one-way valve (61); The control oil port a1 is connected to the right cavity end of the first main valve core (51) and is used to control the first main valve core (51) to move to the left and to the right position; the control oil port b1 is connected to the left cavity end of the first main valve core (51) and is used to control the first main valve core (51) to move to the right and to the left position; the control oil port a2 is connected to the right cavity end of the second main valve core (52) and is used to control the second main valve core (52) to move to the left and to the right position; the control oil port b2 is connected to the left cavity end of the second main valve core (52) and is used to control the second main valve core (52) to move to the right and to the left first position or the left second position; The control oil port a1 is connected to the oil inlet of the reversing valve core (64) through the first damper (66), and the oil inlet of the reversing valve core (64) is connected to the right cavity end of the first main valve core (51), and the oil outlet of the reversing valve core (64) is connected to the T port through the second damper (67); the control oil port a2 is connected to the right control end of the reversing valve core (64), and the left side of the reversing valve core (64) is controlled by the spring (65) and is connected to the T port; It also includes a pilot oil source valve (5), the oil inlet of the pilot oil source valve (5) is connected to the MP port of the energy-saving multi-way valve (8), and the oil outlet of the pilot oil source valve (5) is connected to the two-way ball valve (12) and the pilot valve (13) in sequence. The pilot valve (13) is used to control the first main valve core (51) and the second main valve core (52) through the control oil ports a1, a2, b1, and b2; The composite action includes: rotating the two-way ball valve (12) to switch the two-way ball valve (12) from the first working position to the second working position, controlling the control oil ports a1 and a2 of the energy-saving multi-way valve (8) through the pilot valve (13), so that the first main valve core (51) and the second main valve core (52) move to the left; achieving the displacement ratio of the first main valve core (51) and the second main valve core (52) according to the pressure of the control oil port a2; when the pressure of the control oil port a2 is adjusted to be greater than the pressure set by the spring (65), the switching The valve core (64) switches from the first working position to the second working position. At this time, the pressure of the control oil port a1 is reduced through the first damper (66), the reversing valve core (64), and the second damper (67), thereby reducing the pressure at the right chamber end of the first main valve core (51) and controlling the position change of the first main valve core (51). According to the pressure of the control oil port a2, the pressure reaching the right control end of the first main valve core (51) is adjusted and controlled to form displacement matching between the first main valve core (51) and the second main valve core (52).

2. The loader hydraulic system according to claim 1, characterized in that: The output oil port B1 is connected to the output oil port B2 via a first one-way valve (57) and a second one-way valve (59), and is used to supply oil to the rod chambers of the first actuator (6) and the second actuator (7).

3. The loader hydraulic system according to claim 1, characterized in that: The compound action further includes: The first main valve core (51) and the second main valve core (52) are both switched to the right position, and the oil inlet of the first main valve core (51) passes through the sixth one-way valve (63) to the throttle port of the first main valve core (51) and is connected to the output oil port A1; the fifth one-way valve (62) is connected to the LS2 port, thereby feeding back the load pressure signal of the first actuator (6) to the LS2 port; the oil inlet of the second main valve core (52) passes through the third one-way valve (60) to the throttle port of the second main valve core (52) and is connected to the output oil port A2; the oil inlet of the second main valve core (52) passes through the third one-way valve (60) to the throttle port of the second main valve core (52) and is connected to the LS2 port, thereby feeding back the load pressure signal of the second actuator (7) to the LS2 port. After the two load feedback pressures are compared, the higher pressure is transmitted to the LS2 port, and the lower pressure is cut off due to the one-way valve; thus, the variable pump (1) provides flow according to the opening requirements of the first main valve core (51) and the second main valve core (52).

4. The loader hydraulic system according to claim 1, characterized in that: The compound action further includes: The first main valve core (51) moves to the left to a certain distance. At this time, the output oil port A1 is connected to the first bypass through the first main valve core (51), and the output oil port B1 is connected to the T port through the first main valve core (51); the input oil port P1 enters the first bypass through the first main valve core (51) and the sixth one-way valve (63); the first bypass is connected to the LS2 port through the fifth one-way valve (62); the second main valve core (52) moves to the left to a certain distance. At this time, the output oil port A2 is connected to the second bypass through the second main valve core (52), and the output oil port B2 is connected to the T port through the second main valve core (52); the input oil port P1 enters the second bypass through the second main valve core (52) and the third one-way valve (60), and the second bypass is connected to the LS2 port through the fourth one-way valve (61). Compared with the two, the higher pressure will be connected to the LS2 port, and the lower pressure will be reversely cut off due to the one-way valve.

5. A loader, characterized in that: The loader is equipped with the loader hydraulic system according to any one of claims 1 to 4.

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