A steering valve and hydraulic system

Abstract

The application discloses a steering valve and a hydraulic system. The steering valve comprises control ports a and b connected with a steering handle and a steering gear; working oil ports A and B; a joint port EF connected with a working system; a signal port Ls connected with a first power source; an inlet of a priority valve core connected with an oil inlet P1, an outlet connected with an inlet of a reversing valve core and the joint port EF, and a spring cavity connected with the signal port Ls; an outlet of the reversing valve core connected with the working oil ports A and B; two control ends connected with the control ports a and b respectively; a first electromagnetic valve and a second electromagnetic valve used for switching the steering gear control steering mode and the handle control steering mode; two input ports of a shuttle valve group connected with the working oil ports A and B respectively, and an output port used for simultaneously feeding load pressure to a relief valve and a spring cavity of the priority valve core. The application can be controlled by a steering wheel and a handle, and has the characteristics of small energy loss, good linear degree of pilot pressure, stable steering and the like.

Description

TECHNICAL FIELD

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

[0002] In the prior art, most engineering vehicles such as loaders use steering wheels to steer. In the steering work of the steering wheel, one steering cycle generally circulates about 5-8 times, and most of them have the problem of heavy steering operation. When the loader is working, the steering operation of the loader is relatively frequent. After working for a long time, the driver is prone to fatigue.

[0003] On the one hand, in the prior art, the steering valve commonly used by the loader has the problems of pressure overflow, large power loss, system heating, low energy utilization rate, and unstable traction of the whole machine under the non-steering working condition of the loader. On the other hand, when the loader is walking at high speed, the steering is too flexible when the micro-operation steering is performed, and the "flying" phenomenon occurs, which has safety hazards.

[0004] On the other hand, in the prior art, whether the steering wheel (through the steering gear) is steered, the handle is steered, or the system of steering wheel and handle coexists, the steering valve is flow control, that is, the pressure difference generated by the pilot flow through the pilot hole pushes the valve core to move, which has the problems of nonlinear relationship between the steering speed of the steering wheel and the steering speed of the vehicle, and the asymmetric process of left and right steering. SUMMARY

[0005] In order to solve the problems in the prior art, the present application provides a steering valve and a hydraulic system, which can be controlled by the steering wheel and the handle. The steering valve has the characteristics of small energy loss, good linearity of pilot pressure, and stable steering.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0007] In a first aspect, a steering valve is provided, comprising: an oil inlet P1; control ports a and b for connecting a steering handle and a steering gear; working oil ports A and B for connecting a steering cylinder; a combined port EF for combining with a working system; a signal port Ls for connecting with a signal port of a first power source; an inlet of a priority valve core is connected with the oil inlet P1, one of the outlets of the priority valve core is connected with an inlet of a reversing valve core, another outlet of the priority valve core is connected with the combined port EF, a spring cavity of the priority valve core is connected with the signal port Ls; the outlet of the reversing valve core is connected with the working oil ports A and B; two control ends of the reversing valve core are connected with the control ports a and b respectively, a first electromagnetic valve and a second electromagnetic valve are connected between the two control ends of the reversing valve core, and the first electromagnetic valve and the second electromagnetic valve are used for switching a steering gear control steering mode and a handle control steering mode; two input ports of a shuttle valve group are connected with the working oil ports A and B respectively, and an output port of the shuttle valve group simultaneously feeds back a load pressure to a relief valve and a spring cavity of the priority valve core.

[0008] Further, in the steering gear control steering mode, the steering valve is flow control; when turning left: pilot flow from the steering gear enters from the control port b, part of the pilot oil passes through the first electromagnetic valve and a damping hole e to the control port a; another part of the pilot oil passes through the first electromagnetic valve, a damping hole d in the reversing valve core to the control port a, and then returns to the oil tank through the steering gear, a pressure difference generated by the flow of the pilot oil pushes the reversing valve core to move left, and oil of the first power source is communicated with the steering cylinder through a right position of the steering valve, and the whole machine completes left turning; when turning right: pilot flow from the steering gear enters from the control port a, part of the pilot oil passes through the second electromagnetic valve and the damping hole e to the control port b, another part of the pilot oil passes through the second electromagnetic valve, the damping hole c in the reversing valve core to the control port b, and then returns to the oil tank through the steering gear, a pressure difference generated by the flow of the pilot oil pushes the reversing valve core to move right, and oil of the first power source is communicated with the steering cylinder through a left position of the steering valve, and the whole machine completes right turning.

[0009] Further, the reversing valve core is a three-position six-way valve; the damping hole c and the damping hole d are V-shaped or K-shaped grooves; and the damping hole e is a round hole.

[0010] Further, in the handle control steering mode, the steering valve is pressure control; when turning left: the pilot pressure output by the steering handle through the oil port b1 directly acts on the control port b of the steering valve, and pushes the reversing valve core to move left to complete left turning; when turning right: the pilot pressure output by the steering handle through the oil port a1 directly acts on the control port a of the steering valve, and pushes the reversing valve core to move right to complete right turning.

[0011] Further, a third electromagnetic valve is arranged between the output port of the shuttle valve group and the overflow valve, and the third electromagnetic valve is used to control the transmission of the load signal; when the third electromagnetic valve is not electrified, the load pressure is fed back to the spring cavity of the priority valve core and the overflow valve through the shuttle valve group, so as to keep the pressure difference between the two valve ports of the reversing valve core constant; the overflow valve is used to determine the steering pressure of the system; when the third electromagnetic valve is electrified, the load pressure is connected through the shuttle valve group and the oil return port T1, and the first power source is combined at low pressure to work in the working system or return oil.

[0012] Further, the third electromagnetic valve is a two-position three-way valve.

[0013] Further, a bidirectional buffer valve group is connected between the working oil port A and the working oil port B.

[0014] Further, the first electromagnetic valve and the second electromagnetic valve are two-position two-way valves.

[0015] In the second aspect, a hydraulic system is provided, which comprises the steering valve of the first aspect, the outlet of the first power source is connected to the inlet of the steering valve, the inlet of the pilot oil source, the signal port X of the first power source is connected to the signal port Ls of the steering valve; the outlet of the second power source is connected to the inlet of the master valve, the combination port EF of the steering valve is connected to the inlet of the master valve through the unloading valve, and the master valve is connected to an executing mechanism for realizing combination; when the system pressure of the executing mechanism exceeds the overflow pressure of the unloading valve, the oil from the first power source returns to the hydraulic oil tank through the combination port EF and the T2 port of the unloading valve, for realizing high-pressure small-flow control; the control port a of the steering valve is connected to the oil port a1 of the steering handle and the oil outlet R1 of the second limiting valve at the same time, the oil inlet of the second limiting valve is connected to the oil port R of the steering gear; the control port b of the steering valve is connected to the oil port b1 of the steering handle and the oil outlet L1 of the first limiting valve at the same time, the oil inlet of the first limiting valve is connected to the oil port L of the steering gear; the outlet of the pilot oil source is connected to the oil port P of the steering gear and the oil inlet of the steering handle.

[0016] Further, the executing mechanism comprises any one of a boom, a bucket, a clamp device, a snow removing device, a coal pushing shovel, a grass grabbing machine and the like.

[0017] Compared with the prior art, the present application has the beneficial effects: the inlet of the priority valve core is connected to the oil inlet P1, one of the outlets of the priority valve core is connected to the inlet of the reversing valve core, the other outlet of the priority valve core is connected to the confluence port EF, the spring cavity of the priority valve core is connected to the signal port Ls; the outlet of the reversing valve core is connected to the working oil port A and the working oil port B; the two control ends of the reversing valve core are respectively connected to the control port a and the control port b, and the first electromagnetic valve and the second electromagnetic valve are connected between the two control ends of the reversing valve core, and the first electromagnetic valve and the second electromagnetic valve are used to switch the steering control mode and the handle control mode; the two input ports of the shuttle valve group are respectively connected to the working oil port A and the working oil port B, and the output port of the shuttle valve group simultaneously feeds back the load pressure to the overflow valve and the spring cavity of the priority valve core; both steering control by the steering wheel and steering control by the handle are realized; and the hydraulic system has the characteristics of small energy loss, good linearity of pilot pressure, stable steering, etc. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of a hydraulic system provided by an embodiment of the present application;

[0019] Figure 2 is a schematic diagram of a steering valve provided by an embodiment of the present application;

[0020] In the figure: 1, first power source; 2, second power source; 3, unloading valve; 4, steering valve; 5, steering cylinder; 6, steering handle; 7, first limit valve; 8, second limit valve; 9, steering gear; 10, pilot oil source; 11, hydraulic oil tank; 12, bidirectional buffer valve group; 13, shuttle valve group; 14, reversing valve core; 15, second electromagnetic valve; 16, third electromagnetic valve; 17, overflow valve; 18, priority valve core; 19, first electromagnetic valve. DETAILED DESCRIPTION

[0021] The present application will be further described below in conjunction with the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0022] It should be noted that in the description of the present application, the terms "front", "back", "left", "right", "up", "down", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and do not require the present application to be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application. The terms "front", "back", "left", "right", "up", "down" used in the description of the present application refer to the directions in the drawings, and the terms "inner", "outer" refer to the directions towards or away from the geometric center of a particular component.

[0023] Embodiment one:

[0024] As Figure 1 , Figure 2 shown, a steering valve, comprising an oil inlet P1; a control port a and a control port b for connecting a steering handle (6) and a steering gear (9); a working oil port A and a working oil port B for connecting a steering cylinder (5); a combined port EF for combining with a working system; a signal port Ls for connecting with a signal port X of a first power source (1); an inlet of a priority spool 18 is connected with the oil inlet P1, one of the outlets of the priority spool 18 is connected with an inlet of a reversing spool 14, the other outlet of the priority spool 18 is connected with the combined port EF, a spring cavity of the priority spool 18 is connected with the signal port Ls; an outlet of the reversing spool 14 is connected with the working oil port A and the working oil port B; two control ends of the reversing spool 14 are connected with the control port a and the control port b respectively, a first electromagnetic valve 19 and a second electromagnetic valve 15 are connected between the two control ends of the reversing spool 14 (i.e. the left and right control ends of the reversing spool 14 are communicated), the first electromagnetic valve 19 and the second electromagnetic valve 15 are used for switching a steering gear control steering mode and a handle control steering mode; two input ports of a shuttle valve group 13 are connected with the working oil port A and the working oil port B respectively, an output port of the shuttle valve group 13 simultaneously feeds back a load pressure to a relief valve 17 and the spring cavity of the priority spool 18.

[0025] The control port a simultaneously connects an oil port a1 of the steering handle 6 and an oil outlet R1 of the second limit valve 8; the control port b simultaneously connects an oil port b1 of the steering handle 6 and an oil outlet L1 of the first limit valve 7; the oil inlet P1 is connected with the first power source 1, and a return oil port T1 is used for connecting a hydraulic oil tank 11.

[0026] When the first electromagnetic valve 19 is not electrified, an oil port g and an oil port h are connected; when the second electromagnetic valve 15 is not electrified, an oil port m and an oil port n are connected; when the third electromagnetic valve 16 is not electrified, an oil port o and an oil port p are connected, and an oil port q is connected with a return oil port.

[0027] The first electromagnetic valve 19 and the second electromagnetic valve 15 are used for oil path switching of the steering valve 4 from a steering wheel (through a steering gear) control steering mode (i.e. a steering gear control steering mode) to a steering handle control steering mode; in the steering gear control steering mode, the steering valve is flow control; the first electromagnetic valve 19 and the second electromagnetic valve 15 are not electrified, the oil port g and the oil port h are connected, and the oil port m and the oil port n are connected; when turning left: when a pilot flow from an L port of the steering gear 9 enters from the control port b, part of the pilot oil liquid passes through an oil path gh and a damping hole e to the control port a, and the other part of the pilot oil liquid passes through an oil path gh and a damping hole d to the control port a, and then returns to the hydraulic oil tank 11 through an R port of the steering gear 9, a pressure difference generated by the pilot oil flow pushes the reversing spool 14 to move to the left, and oil liquid of the first power source 1 is connected through a right position of the steering valve 4 and the steering cylinder 5, and the whole machine completes left turning.

[0028] Similarly, when steering right, the pilot flow from the R port of the steering valve 9 enters the control port a, part of the pilot oil passes through the oil passage mn, damping hole e to the control port b, and the other part of the pilot oil passes through the oil passage mn, damping hole c to the control port b, and then returns to the tank through the L port of the steering valve 9. The pressure difference generated by the pilot oil flow pushes the reversing spool 14 to move to the right, the oil of the first power source 1 communicates with the left port of the steering valve 4 and the steering cylinder, and the whole machine completes right steering.

[0029] In the handle control steering mode, the steering valve is pressure controlled. The first solenoid valve 19 and the second solenoid valve 15 are powered on, the oil port g and the oil port h are disconnected, the oil port m and the oil port n are disconnected, the pilot flow path is cut off, the steering handle is turned to the left, and the output pilot pressure directly acts on the control port b of the steering valve 4 through the oil port b1, pushing the reversing spool 14 to move to the left. The oil in the control passage returns to the tank through the control port a of the steering valve 4 and the a1 port of the steering handle, and the whole machine completes left steering; similarly, when steering right, the steering handle is turned to the right, and the output pilot pressure directly acts on the control port a of the steering valve 4 through the oil port a1, pushing the reversing spool 14 to move to the right. The oil in the control passage returns to the hydraulic tank 11 through the control port b of the steering valve 4 and the b1 port of the steering handle, and the whole machine completes left steering.

[0030] A third solenoid valve 16 is provided between the output port of the shuttle valve group 13 and the overflow valve 17, and the third solenoid valve 16 is used to control the transmission of the load signal; when the steering system is working, the third solenoid valve 16 is not powered on, the oil port o and the oil port p are connected, and the oil port q is connected back to the oil; the load pressure is fed back to the spring cavity of the priority valve core 18 and the overflow valve 17 through the shuttle valve group 13, keeping the pressure difference between the two ports of the reversing spool 14 constant, so that the steering flow is only related to the opening size of the reversing spool 14; the excess flow is combined into the working system through the combined port EF; at the same time, the signal port Ls of the steering valve 4 is connected to the signal port X of the first power source 1, and the first power source outputs the steering flow as needed.

[0031] The overflow valve 17 is used to determine the steering pressure of the system.

[0032] When the steering system is not working, the third solenoid valve 16 is powered on, the oil port o and the oil port q are connected, and the load pressure is connected through the shuttle valve group 13 and the oil return, so that the first power source 1 is combined with the working system or returns to the oil at low pressure, so that the system power loss is small and energy saving.

[0033] The bidirectional buffer valve group 12 connects the steering oil cylinder 5, making the steering more stable and reducing vibration and impact during steering.

[0034] The first solenoid valve 19 and the second solenoid valve 15 are two-position two-way valves. The third solenoid valve 16 is a two-position three-way valve.

[0035] The reversing valve core 14 is a three-position six-way valve; the damping holes c and d are V-shaped or K-shaped grooves, the linearity of the area curve of the V-shaped or K-shaped grooves is good, the pilot flow is relatively stable, and the steering is stable.

[0036] Embodiment two:

[0037] Based on the steering valve described in embodiment one, the hydraulic system provided in the embodiment comprises the steering valve described in embodiment one, the outlet of the first power source 1 is connected to the oil inlet P1 of the steering valve and the inlet of the pilot oil source 10, the signal port X of the first power source 1 is connected to the signal port Ls of the steering valve; the outlet of the second power source 2 is connected to the inlet of the master valve, the confluence port EF of the steering valve 4 is connected to the inlet of the master valve through the unloading valve 3, and the master valve is connected to the actuator for realizing the confluence; when the system pressure of the actuator exceeds the overflow pressure of the unloading valve 3, the oil from the first power source 1 returns to the hydraulic oil tank 11 through the confluence port EF and the T2 port of the unloading valve 3, for realizing the control of high pressure and small flow; the control port a of the steering valve is connected to the oil port a1 of the steering handle 6 and the oil outlet R1 of the second limiting valve 8 at the same time, the oil inlet of the second limiting valve 8 is connected to the oil port R of the steering gear 9; the control port b of the steering valve is connected to the oil port b1 of the steering handle 6 and the oil outlet L1 of the first limiting valve 7 at the same time, the oil inlet of the first limiting valve 7 is connected to the oil port L of the steering gear 9; the outlet of the pilot oil source 10 is connected to the oil port P of the steering gear 9 and the oil inlet of the steering handle 6.

[0038] For some working machines in the scene of working in a fixed area, for example, when the loader is loading and unloading materials in the mine, the running track is basically fixed, and the steering operation of the loader is also basically fixed, at this time, in order to improve the work efficiency, the handle control steering mode is selected.

[0039] For other working conditions, when the steering handle is needed, the steering gear control steering mode is selected.

[0040] The first power source 1 and the second power source 2 can be a fixed displacement pump or a variable displacement pump.

[0041] The steering handle 6 can be a hydraulic control handle or an electric control handle.

[0042] The actuator is any one of the implements such as a boom, a bucket, a clamp device, a snow removing device, a coal pushing shovel, a grass grabbing machine and the like.

[0043] The application realizes that the engineering vehicle such as loader can be controlled by steering wheel and handle, improves work efficiency; low pressure converges to the working system in non-steering condition, eliminates power loss in non-steering condition, saves energy; when the pressure control and steering wheel flow control of the steering handle are realized, the setting of the pilot hole makes the pilot pressure linearity good, solves the problem that the flow control of the existing steering valve causes the steering impact vibration of the whole machine to be large and unstable.

[0044] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make some improvements and modifications without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A diverter valve characterized by, The application relates to a steering valve. The steering valve comprises: an oil inlet P1; control ports a and b for connecting a steering handle and a steering gear; working oil ports A and B for connecting a steering cylinder; a joint port EF for jointing with a working system; a signal port Ls for connecting with a signal port of a first power source; an inlet of a priority valve core (18) is connected with the oil inlet P1, one outlet of the priority valve core (18) is connected with an inlet of a reversing valve core (14), another outlet of the priority valve core (18) is connected with the joint port EF, and a spring cavity of the priority valve core (18) is connected with the signal port Ls; an outlet of the reversing valve core (14) is connected with the working oil ports A and B; two control ends of the reversing valve core (14) are respectively connected with the control ports a and b, and a first electromagnetic valve (19) and a second electromagnetic valve (15) are connected between the two control ends of the reversing valve core (14), and the first electromagnetic valve (19) and the second electromagnetic valve (15) are used for switching a steering gear control steering mode and a handle control steering mode; two input ports of a shuttle valve group (13) are respectively connected with the working oil ports A and B, and an output port of the shuttle valve group (13) simultaneously feeds back load pressure to an overflow valve (17) and the spring cavity of the priority valve core (18); 2. The diverter valve of claim 1, wherein, a third electromagnetic valve (16) is arranged between the output port of the shuttle valve group (13) and the overflow valve (17), and the third electromagnetic valve (16) is used for controlling transmission of the load signal; when the third electromagnetic valve (16) is not electrified, the load pressure is simultaneously fed back to the overflow valve (17) and the spring cavity of the priority valve core (18) through the shuttle valve group (13), so that a pressure difference between two valve ports of the reversing valve core (14) is kept constant; the overflow valve (17) is used for determining a steering pressure of the system; when the third electromagnetic valve (16) is electrified, the load pressure is connected through the shuttle valve group (13) and an oil return port T1, and the first power source (1) is jointed to the working system at low pressure or returns oil. In the steering gear control steering mode, the steering valve is flow control; when steering left, pilot flow from the steering gear enters from the control port b, part of the pilot oil passes through the first electromagnetic valve (19) and a damping hole e to the control port a; another part of the pilot oil passes through the first electromagnetic valve (19), a damping hole d in the reversing valve core (14) to the control port a, and then returns to the oil tank through the steering gear; a pressure difference generated by the flow of the pilot oil drives the reversing valve core (14) to move leftwards, oil of the first power source (1) is connected through a right position of the steering valve (4) and the steering cylinder, and the whole machine completes left steering; 3. The diverter valve of claim 2, wherein, when steering right, pilot flow from the steering gear enters from the control port a, part of the pilot oil passes through the second electromagnetic valve (15) and the damping hole e to the control port b, another part of the pilot oil passes through the second electromagnetic valve (15), a damping hole c in the reversing valve core (14) to the control port b, and then returns to the oil tank through the steering gear; a pressure difference generated by the flow of the pilot oil drives the reversing valve core (14) to move rightwards, oil of the first power source (1) is connected through a left position of the steering valve (4) and the steering cylinder, and the whole machine completes right steering. The reversing valve core (14) is a three-position six-way valve; the damping hole c and the damping hole d are V-shaped or K-shaped grooves; and the damping hole e is a circular hole.

4. The diverter valve of claim 1, wherein, In the handle control steering mode, the steering valve is pressure controlled; when steering left: the steering handle outputs pilot pressure through oil port b1, which directly acts on the control port b of the steering valve (4), pushing the reversing spool (14) to move left, completing left steering; When steering right, the steering handle outputs pilot pressure through oil port a1, which directly acts on the control port a of the steering valve (4), pushing the reversing spool (14) to move right, completing right steering.

5. The diverter valve of claim 1, wherein, The third electromagnetic valve (16) is a two-position three-way valve.

6. The diverter valve of claim 1, wherein, A bidirectional buffer valve group (12) is connected between the working oil port A and the working oil port B.

7. The diverter valve of claim 1, wherein, The first electromagnetic valve (19) and the second electromagnetic valve (15) are two-position two-way valves.

8. A hydraulic system characterized by, The steering valve according to any one of claims 1-7, an outlet of the first power source (1) is connected to an oil inlet P1 of the steering valve, an inlet of a pilot oil source (10), a signal port X of the first power source (1) is connected to a signal port Ls of the steering valve; an outlet of the second power source (2) is connected to an inlet of a main control valve, a confluence port EF of the steering valve (4) is connected to the inlet of the main control valve through an unloading valve (3), the main control valve is connected to an actuator for realizing confluence; when the system pressure of the actuator exceeds the overflow pressure of the unloading valve (3), the oil from the first power source (1) returns to a hydraulic oil tank (11) through the confluence port EF and a T2 port of the unloading valve (3), for realizing high-pressure small-flow control; a control port a of the steering valve is connected to an oil port a1 of a steering handle (6) and an oil outlet R1 of a second limit valve (8), an oil inlet of the second limit valve (8) is connected to an oil port R of a steering gear (9); a control port b of the steering valve is connected to an oil port b1 of the steering handle (6) and an oil outlet L1 of a first limit valve (7), an oil inlet of the first limit valve (7) is connected to an oil port L of the steering gear (9); an outlet of the pilot oil source (10) is connected to an oil port P of the steering gear (9) and an oil inlet of the steering handle (6).

9. The hydraulic system of claim 8, wherein, The actuator includes any one of a boom, a bucket, a clamp device, a snow removing device, a coal pushing shovel, and a grass grabbing machine.

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