Load-sensitive combination valve body

Abstract

The utility model relates to the technical field of tractor hydraulic valve groups, in particular to a load-sensitive combination valve body. Comprising a valve body, an oil inlet P, an oil return port T, a working oil port A and a working oil port B are formed in the valve body, the working oil port B and the oil return port T are communicated through a switching valve cavity and can also be directly communicated through a first bypass cavity, and a single-double-acting switch used for controlling opening and closing of the first bypass cavity is arranged on the first bypass cavity. When the single-action and double-action switch is closed, the combination valve in the device can be connected with a double-interface executing mechanism, and when the single-action and double-action switch is opened, the combination valve in the device can be connected with a single-interface executing mechanism, so that the applicability of the device is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to tractor hydraulic valve group technical field, concretely relates to a load sensitive combination valve body. BACKGROUND

[0002] In the engineering machinery hydraulic system, load sensitive technology is one of the core means to realize high efficiency energy distribution and energy saving control. As the key element of the technology, load sensitive combination valve can dynamically adjust system pressure and flow according to the load demand of the actuator, so as to optimize energy utilization efficiency and improve operation precision. The valve body, as the device directly connected with the actuator in the combination valve, its specific structure directly affects the energy efficiency of the combination valve.

[0003] In the prior art, the load sensitive combination valve body is usually composed of a valve body and a valve rod installed on the valve body and movable, and a P oil inlet, a T oil return port, an oil channel, an A working oil port, a B working oil port and a hydraulic lock are arranged on the valve body. By controlling the three states of the valve rod, the three states of the actuator are realized. Taking a tractor driving an agricultural implement through a hydraulic cylinder as an example, the A working oil port of the valve body is communicated with the lower oil chamber (i.e. the rodless chamber) of the hydraulic cylinder, the B working oil port is communicated with the upper oil chamber (i.e. the rod chamber) of the hydraulic cylinder, and the three states of the valve rod correspond to the static, elongation and contraction of the hydraulic cylinder rod body, and correspond to the static, lifting and falling of the agricultural implement.

[0004] However, with the continuous development of engineering machinery hydraulic technology, the structure of part of the actuators has also been simplified. Taking the hydraulic cylinder as an example, part of the hydraulic cylinders only retains one interface, i.e. only the lower oil chamber of the hydraulic cylinder is communicated with the A working oil port of the valve body, and the contraction of the hydraulic cylinder rod body can be realized through the cooperation of the self weight of the agricultural implement and the valve body, and the structure is simpler.

[0005] The existing double working oil port valve body can only be used on the double interface actuator, and the single working oil port valve body can only be used on the single interface actuator, which is relatively limited in use and has poor applicability. UTILITY MODEL CONTENTS

[0006] In view of the above problems, the utility model provides a load sensitive combination valve body to solve the problem of the load sensitive combination valve body in the prior art that is relatively limited in use and has poor applicability.

[0007] The utility model discloses a load sensitive combination valve body, including the valve body, the valve body is equipped with the transverse setting switch valve cavity, install the valve rod of being able to switch three position conditions in switch valve cavity, its characterized in that, be equipped with P inlet, A working oil port, B working oil port and T oil return port on the valve body, P inlet communicates with switch valve cavity through oil inlet chamber, B working oil port communicates with switch valve cavity through first working chamber, T oil return port communicates with switch valve cavity through oil return chamber, A working oil port communicates with switch valve cavity through second working chamber, be equipped with the hydraulic lock for controlling the on-off between second working chamber and switch valve cavity on second working chamber, be equipped with the first bypass chamber of communicating first working chamber and T oil return port on the valve body, be equipped with the single double -acting switch of being able to control the on-off of first bypass chamber and T oil return on first bypass chamber,

[0008] When the valve rod is in the first state, the oil inlet chamber, the first working chamber, the second working chamber and the oil return chamber are not communicated with each other; when the valve rod is in the second state, the oil inlet chamber is communicated with the first working chamber through the switch valve cavity, and the second working chamber is communicated with the oil return chamber through the switch valve cavity; when the valve rod is in the third state, the oil inlet chamber is communicated with the second working chamber through the switch valve cavity, and the first working chamber is communicated with the oil return chamber through the switch valve cavity.

[0009] Through the above structure, when the single double -acting switch is in the closed state, the device can be applied to the actuator with a double interface, and when the single double -acting switch is in the open state, the device can be connected with the actuator with a single interface for use, so that the use range of the device is wider, and the applicability of the device is increased.

[0010] Preferably, the single double -acting switch includes a switch cavity arranged on the top of the valve body, the right end of the first bypass chamber is communicated with the middle part of the switch cavity, the bottom end of the switch cavity is communicated with the T oil return port, the top of the switch cavity is fixedly installed with a mounting seat, the inside of the mounting seat is sleeved with a mounting column capable of moving up and down, and the bottom of the mounting column is fixedly installed with a plug for plugging the switch cavity; when the single double -acting switch is in the closed state, the plug is located in the switch cavity below the first bypass chamber and plugs it, and when the single double -acting switch is in the open state, the plug is located in the upper part of the connection between the first bypass chamber and the switch cavity, and the first bypass chamber is communicated with the T oil return port through the switch cavity. The communication between the first bypass chamber and the switch cavity is controlled by the up and down movement of the mounting column and the plug, so that the structure of the device is simple and the operation is convenient.

[0011] Preferably, the top of the mounting seat is provided with an internal thread, the top of the mounting column is provided with an external thread, and the mounting seat and the mounting column are matched through threads. The up and down movement of the mounting column is realized through the thread matching mode, so that the position of the mounting column can be controlled at will, and the use is more convenient.

[0012] Preferably, a first sealing ring is arranged between the mounting seat and the valve body, a second sealing ring is arranged between the mounting column and the mounting seat, and a third sealing ring is arranged between the plug and the switching cavity. The arrangement of multiple sealing rings prevents oil leakage.

[0013] Preferably, the oil inlet cavity includes a first oil inlet cavity and a second oil inlet cavity, one end of the first oil inlet cavity is in communication with the P oil inlet, the other end is in communication with the switching valve cavity, and the second oil inlet cavity is located on one side of the first oil inlet cavity, both ends of the second oil inlet cavity are in communication with the switching valve cavity.

[0014] When the valve rod is in the first state, the first oil inlet cavity is not in communication with the second oil inlet cavity; when the valve rod is in the second state, the first oil inlet cavity is in communication with the second oil inlet cavity and the first working cavity; when the valve rod is in the third state, the first oil inlet cavity is not in communication with the second oil inlet cavity, and the first oil inlet cavity is in communication with the second working cavity.

[0015] Preferably, the switching valve cavity is sequentially provided with a first cavity in communication with one end of the second oil inlet cavity, a second cavity in communication with the first working cavity, a third cavity in communication with the oil return cavity, a fourth cavity in communication with the lower lock cavity, a fifth cavity in communication with the other end of the second oil inlet cavity, and a sixth cavity in communication with the first working cavity; the valve rod is provided with a first groove capable of controlling the on-off of the first cavity and the second cavity and the second cavity and the third cavity, a second groove capable of controlling the on-off of the third cavity and the fourth cavity, the fourth cavity and the fifth cavity, a third groove capable of controlling the on-off of the fifth cavity and the sixth cavity, and a fourth groove. The arrangement of the grooves on the valve rod and the cavities on the switching valve cavity enables the left and right movement of the valve rod to switch the communication of different cavities.

[0016] Preferably, the hydraulic lock includes an upper lock cavity and a lower lock cavity arranged on the top of the valve body, the bottom of the upper lock cavity is in communication with the left end of the second working cavity, the top of the lower lock cavity is in communication with the left end of the second working cavity, a first valve core capable of blocking the lower lock cavity is slidably arranged in the upper lock cavity, a top seat is fixedly arranged on the top of the upper lock cavity, a first spring is fixedly connected to the bottom end of the top seat, the bottom end of the first spring is fixedly connected to the first valve core, and a second valve core capable of upwardly fixing the first valve core is slidably arranged below the first valve core of the valve body. The arrangement of the hydraulic lock enables the oil to flow in one direction only, making the device more stable.

[0017] Preferably, the bottom of the second valve core is in contact with the bottom of the second groove, the bottom of the second valve core is hemispherical, and the right side wall of the second groove is inclined. When the valve rod is in the first state, the bottom of the second valve core is at the bottom of the slope. The arrangement of the second valve core and the second groove enables the second valve core to move upward and lift the first valve core when the valve body switches from the first state to the second state, thereby opening the hydraulic lock.

[0018] Preferably, the valve body is located below the valve stem, and a transversely arranged pressure compensation valve is further arranged at the position, the pressure compensation valve comprises a compensation valve cavity, a compensation valve core capable of moving left and right is arranged in the compensation valve cavity, a third spring is fixedly arranged at the left end of the compensation valve cavity, and the right end of the third spring is fixedly connected with the compensation valve core; a P oil inlet is in communication with the right part of the compensation valve cavity, the end of the first working chamber away from the valve stem is in communication with the middle part of the compensation valve cavity, and the middle part of the second working chamber is in communication with the left part of the compensation valve cavity. Through the arrangement of the pressure compensation valve, the difference between the pump outlet pressure and the load pressure is kept constant, the flow is automatically adapted to the load change, and the device is suitable for complex working conditions requiring stable speed and pressure.

[0019] Preferably, the valve body is located below the valve stem, and a transversely arranged pressure compensation valve is further arranged at the position, the pressure compensation valve comprises a compensation valve cavity, a compensation valve core capable of moving left and right is arranged in the compensation valve cavity, a third spring is fixedly arranged at the left end of the compensation valve cavity, and the right end of the third spring is fixedly connected with the compensation valve core; a P oil inlet is in communication with the right part of the compensation valve cavity, the end of the first working chamber away from the valve stem is in communication with the middle part of the compensation valve cavity, and the middle part of the second working chamber is in communication with the left part of the compensation valve cavity. Through the arrangement of the pressure compensation valve, the difference between the pump outlet pressure and the load pressure is kept constant, the flow is automatically adapted to the load change, and the device is suitable for complex working conditions requiring stable speed and pressure.

[0020] In summary, the beneficial effects of the utility model lie in:

[0021] 1. Through the arrangement of a first bypass chamber, the first working chamber has an additional branch capable of flowing to the T return oil port. When the B working oil port is not connected with the actuator, the oil in the first oil inlet chamber and the second oil inlet chamber can return to the T return oil port through the first working chamber and the first bypass chamber, so that the pressure of the two oil inlet chambers is zeroed, and the pressure regulating valve is closed, thereby not affecting the normal work of the valve body. When the B working oil port and the A working oil port are both connected with the actuator, the single-acting and double-acting switch only needs to be closed to be normally used. Therefore, the device can be applied to single-interface actuators and double-interface actuators, and the applicability of the device is increased.

[0022] 2. Through the arrangement of the built-in hydraulic lock of the device, a valve sleeve is no longer needed, the structure of the device is simpler, and the flow capacity of the hydraulic lock in the device is larger on the basis of occupying the same space. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 the cross-sectional view of the valve body when the single-acting and double-acting switch is closed and the valve stem is in the first state; Figure 2 the cross-sectional view of the valve body when the single-acting and double-acting switch is closed and the valve stem is in the second state;

[0024] Figure 3 the cross-sectional view of the valve body when the single-acting and double-acting switch is closed and the valve stem is in the third state;

[0025] Figure 4 the cross-sectional view of the valve body when the single-acting and double-acting switch is opened and the valve stem is in the second state;

[0026] Figure 5 is a local enlarged view of A area;

[0027] Figure 6 is a local enlarged view of B area;

[0028] Figure 7 is a local enlarged view of C area.

[0029] In the figure: 1-driving mechanism; 2-valve body; 21-valve rod; 211-first groove; 212-second groove; 213-third groove; 214-fourth groove; 22-switching valve cavity; 221-first cavity; 222-second cavity; 223-third cavity; 224-fourth cavity; 225-fifth cavity; 226-sixth cavity; 23-T oil return port; 24-oil return cavity;

[0030] 3-B working oil port; 31-first working cavity; 32-first bypass cavity;

[0031] 4-single / double acting switch; 41-mounting seat; 42-mounting column; 43-first sealing ring; 44-second sealing ring; 45-third sealing ring; 46-plug; 47-switch cavity;

[0032] 5-hydraulic lock; 51-top seat; 52-first spring; 53-flap; 54-first valve core; 55-second spring; 56-steel ball; 57-second valve core; 58-upper lock cavity; 59-clamping groove; 591-mounting hole; 592-top hole; 593-lower lock cavity;

[0033] 6-A working oil port; 61-second working cavity; 62-second bypass cavity; 63-overflow valve; 64-overflow port;

[0034] 7-pressure compensation valve; 71-compensation valve core; 72-third spring; 73-compensation valve cavity;

[0035] 8-P oil inlet port; 81-first oil inlet cavity; 82-second oil inlet cavity. DETAILED DESCRIPTION

[0036] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present application, but not to limit the scope of the present application.

[0037] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "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 simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0038] The following is a description of the preferred embodiments of the present application in conjunction with the drawings.

[0039] As Figures 1 to 4 shown, the utility model provides a load sensitive combination valve body, including valve body 2, be equipped with the switching valve cavity 22 that transversely penetrates valve body 2 in valve body 2, switching valve cavity 22 inside sliding installation can be by drive mechanism 1 drive left and right movement and carry out state switching valve stem 21, valve stem 21 mainly have first, second and third three states. Valve body 2 is equipped with the P oil inlet 8 located below valve stem 21, valve body 2 is equipped with A working oil port 6, B working oil port 3 and T oil return port 23 located above valve stem 21. P oil inlet 8 is communicated with switching valve cavity 22 through oil inlet cavity, B working oil port 3 is communicated with switching valve cavity 22 through first working cavity 31, T oil return port 23 is communicated with switching valve cavity 22 through oil return cavity 24, A working oil port 6 is communicated with switching valve cavity 22 through second working cavity 61. Be equipped with hydraulic lock 5 for controlling the on-off between second working cavity 61 and switching valve cavity 22 on second working cavity 61, be equipped with single double-acting switch 4 that can control the on-off between first bypass cavity 32 and T oil return port 23 on first bypass cavity 32.

[0040] When valve stem 21 is in the first state, oil inlet cavity, first working cavity 31, second working cavity 61, oil return cavity 24 are not communicated with each other, when valve stem 21 is in the second state, oil inlet cavity is communicated with first working cavity 31 through switching valve cavity 22, second working cavity 61 is communicated with oil return cavity 24 through switching valve cavity 22, when valve stem 21 is in the third state, oil inlet cavity is communicated with second working cavity 61 through switching valve cavity 22, first working cavity 31 is communicated with oil return cavity 24 through switching valve cavity 22.

[0041] Among them, oil inlet cavity includes first oil inlet cavity 81 and second oil inlet cavity 82, one end of first oil inlet cavity 81 is communicated with P oil inlet 8, the other end is communicated with switching valve cavity 22, second oil inlet cavity 82 is located on one side of first oil inlet cavity 81, both ends of second oil inlet cavity 82 are communicated with switching valve cavity 22.

[0042] When the valve rod 21 is in the first state, the first oil inlet cavity 81 is not communicated with the second oil inlet cavity 82; when the valve rod 21 is in the second state, the first oil inlet cavity 81 is communicated with the second oil inlet cavity 82 and the first working cavity 31; when the valve rod 21 is in the third state, the first oil inlet cavity 81 is not communicated with the second oil inlet cavity 82, and the first oil inlet cavity 81 is communicated with the second working cavity 61.

[0043] As shown in Figure 1 , Figure 4 , Figure 5 The single / dual action switch 4 includes a switch cavity 47 arranged at the top of the valve body 2, the right end of the first bypass cavity 32 is communicated with the middle part of the switch cavity 47, the bottom end of the switch cavity 47 is communicated with the T oil return port 23, and the top of the switch cavity 47 is fixedly installed with a mounting seat 41, the inner side of the mounting seat 41 is sleeved with a mounting column 42 capable of moving up and down, and the bottom of the mounting column 42 is fixedly installed with a plug 46 for plugging the switch cavity 47. When the single / dual action switch 4 is in the closed state, the plug 46 is located below the first bypass cavity 32 in the switch cavity 47 and plugs it, and when the single / dual action switch 4 is in the open state, the plug 46 is located in the upper part of the switch cavity 47 at the connection of the first bypass cavity 32, and the first bypass cavity 32 is communicated with the T oil return port 23 through the switch cavity 47.

[0044] The up and down movement of the mounting column 42 is mainly realized by threaded cooperation, specifically, an internal thread is arranged on the inner side of the mounting seat 41, and an external thread is arranged on the outer side of the mounting column 42, and the two are installed by threaded cooperation. When the A working oil port 6 and the B working oil port 3 are both connected with the actuator, the single / dual action switch 4 is in the closed state, when only the A working oil port 6 is connected with the actuator, at this time the B working oil port 3 is plugged by the sealing plug, the mounting column 42 is twisted to move upward, at this time the single / dual action switch 4 is opened, and the first working cavity 31 is communicated with the T oil return port 23 through the first bypass cavity 32 and the switch cavity 47.

[0045] In order to prevent oil from leaking out of the gap between the structures of the single / dual action switch 4 and affecting the sealing and isolation effect, a first sealing ring 43 is installed between the mounting seat 41 and the valve body 2, a second sealing ring 44 is arranged between the mounting column 42 and the mounting seat 41, and a third sealing ring 45 is arranged between the plug 46 and the switch cavity 47.

[0046] As shown in Figure 1 , Figure 7As shown, the switching valve chamber 22, from left to right, is provided with a first chamber 221 communicating with one end of the second oil inlet chamber 82, a second chamber 222 communicating with the first working chamber 31, a third chamber 223 communicating with the return oil chamber 24, a fourth chamber 224 communicating with the lower lock chamber 593, a fifth chamber 225 communicating with the other end of the second oil inlet chamber 82, and a sixth chamber 226 communicating with the first working chamber 31. The valve stem 21, from left to right, is provided with a first groove 211, a second groove 212, a third groove 213, and a fourth groove 214. When the valve stem 21 is in the first state, the six chambers of the switching valve chamber 22 are not connected; when the valve stem 21 is in the second state, the fifth chamber 225 and the sixth chamber 226 are connected through the fourth groove 214, the first chamber 221 and the second chamber 222 are connected through the first groove 211, and the third chamber 223 and the fourth chamber 224 are connected through the second groove 212; when the valve stem 21 is in the third state, the fourth chamber 224 and the fifth chamber 225 are connected through the second groove 212, the fifth chamber 225 and the sixth chamber 226 are connected through the third groove 213, and the second chamber 222 and the third chamber 223 are connected through the first groove 211.

[0047] by Figure 2 , Figure 3 For example, when the valve stem 21 is in the second state, the first groove 211 is located between the first cavity 221 and the second cavity 222, the second groove 212 is located between the third cavity 223 and the fourth cavity 224, and the fourth groove 214 is located between the fifth cavity 225 and the sixth cavity 226. When the valve stem 21 is in the third state, the first groove 211 is located between the second cavity 222 and the third cavity 223, the second groove 212 is located between the fourth cavity 224 and the fifth cavity 225, and the third groove 213 is located between the fifth cavity 225 and the sixth cavity 226.

[0048] like Figure 1 , Figure 6 As shown, the hydraulic lock 5 includes an upper locking cavity 58 and a lower locking cavity 593 located on the top of the valve body 2. The bottom end of the upper locking cavity 58 is connected to the top end of the lower locking cavity 593. The bottom of the upper locking cavity 58 is connected to the left end of the second working cavity 61. The top of the lower locking cavity 593 is connected to the left end of the second working cavity 61. A first valve core 54 that can slide up and down and block the lower locking cavity 593 is installed in the upper locking cavity 58. A second valve core 57 that can fix the first valve core 54 upward is slidably installed on the valve body 2 below the first valve core 54. A reset mechanism for pressing the first valve core 54 downward is also installed in the upper locking cavity 58 above the first valve core 54.

[0049] The reset mechanism can be any mechanism capable of blocking the first spool 54 when there is no pressure, such as by the provision of a damper. In this embodiment, the reset mechanism comprises a top seat 51 located at the top of the upper locking chamber 58 and fixedly connected to the valve body 2, the bottom end of the top seat being fixedly connected to a first spring 52, and the lower end of a second spring 55 being fixedly connected to the first spool 54.

[0050] The top of the first spool 54 is provided with a clamping groove 59, the bottom of the clamping groove 59 being fixedly provided with a baffle 53, the bottom end of the first spring 52 being fixedly connected to the baffle 53, the middle of the first spool 54 being provided with a mounting hole 591 in communication with the clamping groove 59, the bottom of the first spool 54 being provided with a top hole 592 in communication with the mounting hole 591, the mounting hole 591 being provided with the second spring 55, the top end of the second spring 55 being fixedly connected to the baffle 53, the bottom end of the second spring 55 being fixedly connected to a steel ball 56, when the steel ball 56 is located at the very bottom of the mounting hole 591, the steel ball 56 can completely block the top hole 592, the top of the second spool 57 being provided with an upward protrusion, when the second spool 57 moves upward, the protrusion can lift the steel ball 56.

[0051] The bottom of the second spool 57 is located in the second groove 212 and is always in contact with the second groove 212, the bottom of the second spool 57 being hemispherical, the right side wall of the second groove 212 being an inclined surface, when the valve stem 21 is in the first state, the bottom of the second spool 57 is located at the very bottom of the inclined surface.

[0052] When the valve stem 21 moves to the left, the second spool 57 moves upward, first lifting the steel ball 56 to complete the circulation of the pilot oil and balance the pressure, as the valve stem 21 continues to move to the left, the second spool 57 lifts the first spool 54 upward, when the valve stem 21 is in the second state, the first spool 54 is lifted open, the second working chamber 61 is in communication with the lower locking chamber 593. When the valve stem 21 moves to the right, the steel ball 56 is lifted by the oil pressure, and then the first spool 54 is also lifted by the oil pressure, so that the second working chamber 61 is in communication with the lower locking chamber 593.

[0053] In this device, the hydraulic lock 5 adopts an internal hydraulic lock 5 structure, the first spool 54 is directly placed in the upper locking chamber 58, and a valve sleeve is no longer needed, so that the structure of the device is simpler, and the flow capacity of the hydraulic lock 5 in the device is larger on the basis of occupying the same space.

[0054] As a further illustration of the present instance, in order to prevent the pressure at the second working chamber 61 from being too large, the valve body 2 is also provided with an overflow valve 63 at a position above the valve stem 21, the second working chamber 61 is communicated with a second bypass chamber 62, and the second bypass chamber 62 is communicated with an overflow port 64 through the overflow valve 63. When the pressure of the second working chamber 61 is too large, the overflow valve 63 will be opened, and the oil will flow into the overflow port 64 through the second bypass chamber 62, and the overflow port 64 is communicated with the oil tank. The overflow valve 63 also belongs to the conventional prior art, which is a protection valve, and will not be described in detail here.

[0055] As a further illustration of the present instance, the pressure compensation valve 7 in the present device mainly includes a compensation valve chamber 73 provided on the valve body 2, a compensation valve spool 71 capable of moving left and right is installed in the compensation valve chamber 73, a third spring 72 is fixedly installed at the leftmost end of the compensation valve chamber 73, and the rightmost end of the third spring 72 is fixedly connected with the compensation valve spool 71. The P oil inlet 8 is communicated with the right part of the compensation valve chamber 73, the middle part of the compensation valve chamber 73 is communicated with the end of the first working chamber 31 away from the valve stem 21, and the middle part of the second working chamber 61 is communicated with the left part of the compensation valve chamber 73. The compensation valve spool 71 can block the compensation valve chamber 73 between the first working chamber 31 and the P oil inlet 8, and when the compensation valve spool 71 moves to the right, the flow of the P oil inlet 8 to the first working chamber 31 can be adjusted, thereby realizing the adjustment of the pressure; specifically, the pressure at the P oil inlet 8 and the pressure in the first working chamber 31 plus the pressure in the second working chamber 61 plus the elastic force of the third spring 72 are compared, thereby realizing the automatic adjustment of the pressure compensation valve 7.

[0056] As a further illustration of the present instance, the valve body 2 is also provided with an LS oil way and a shuttle valve. The shuttle valve selects the pressure in multiple valve bodies and transmits the largest pressure signal to the flow pump through the LS oil way to control the flow. This is a conventional technical means of sensitive valve and is well known to those skilled in the art, and therefore will not be described in detail here.

[0057] Taking a hydraulic cylinder as an example, when the A working oil port 6 is connected with the rodless chamber of the hydraulic cylinder, the B working oil port 3 is connected with the cylinder chamber of the hydraulic cylinder, and the single / dual action switch 4 is in the closed state, the working principle is as follows:

[0058] When the valve stem 21 is in the first state, the P oil inlet 8 does not introduce oil into the valve body 2, and the hydraulic cylinder is in a static state.

[0059] When the valve rod 21 is in the second state, the hydraulic lock 5 is opened under the action of the second spool 57, and the oil flowing into the P inlet port 8 flows through the pressure compensation valve 7, the first oil inlet cavity 81, the fourth groove 214, the second oil inlet cavity 82, the first groove 211, the first working cavity 31 in turn, and finally flows to the rod cavity through the B working oil port 3; at this time, the A working oil port 6 also introduces oil into the valve body, and this part of the oil flows through the second working cavity 61, the lower lock cavity 593, the second groove 212, and the oil return cavity 24 in turn, and finally flows back to the oil tank through the T return port 23; at this time, the piston rod of the hydraulic cylinder is withdrawn into the hydraulic cylinder.

[0060] When the valve rod 21 is in the third state, the oil flowing into the P inlet port 8 flows through the pressure regulating valve, the first oil inlet cavity 81, the third groove 213, the second groove 212, and the lower lock cavity 593 in turn, and then lifts the first spool 54, flows through the second working cavity 61, and then flows from the A working oil port 6 to the rodless cavity of the hydraulic cylinder; at the same time, the B working oil port 3 also introduces oil into the valve body 2, and this part of the oil flows through the first working cavity 31, the first groove 211, and the oil return cavity 24, and then flows back to the oil tank through the T return port 23; at this time, the piston rod of the hydraulic cylinder is extended outward.

[0061] When the A working oil port 6 is connected with the rodless cavity of the hydraulic cylinder, the B working oil port 3 is blocked, and the single / dual-acting switch 4 is in the open state, the working principle is as follows:

[0062] When the valve rod 21 is in the first state, the P inlet port 8 does not introduce oil, and at this time the hydraulic cylinder is in a static state. When the valve rod 21 is in the third state, oil flows from the P inlet port 8 to the A working oil port 6, and the process is consistent with the above-mentioned double interface, and the oil in the first working cavity 31 also flows into the T return port 23, resulting in no pressure in the first working cavity 31, and at this time the piston rod of the hydraulic cylinder is in an extended state.

[0063] When the piston rod is pressed back by the mechanical gravity, at this time the valve rod 21 is in the second state, and the oil in the rodless cavity of the hydraulic cylinder will flow through the A working oil port 6 to the T return port 23, and at this time there is no oil in the first working cavity 31, i.e. no pressure, but there is oil in the first oil inlet cavity 81 and the second oil inlet cavity 82, at this time this part of the oil will flow into the T return port 23 along the first working cavity 31 and the first bypass cavity 32, thereby reducing or even eliminating the pressure in the first oil inlet cavity 81 and the second oil inlet cavity 82, at this time the pressure at the P inlet port 8 is greater than the spring force of the third spring 72 plus the pressure in the first oil inlet cavity 81 and the second oil inlet cavity 82, the compensation spool 71 moves to the left, so that the first oil inlet cavity 81 is no longer connected with the P inlet port 8, and oil is no longer supplied to the valve body 2, thereby realizing the withdrawal of the piston rod.

[0064] The above merely is the preferred implementation form of the present application, and it should be noted that, for the ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and substitutions can be made, and these improvements and substitutions should also be considered as the protection scope of the present application.

Claims

1. A load-sensitive combined valve body, comprising a valve body (2), a transversely arranged switching valve cavity (22) is arranged in the valve body (2), a valve rod (21) capable of switching three position states is installed in the switching valve cavity (22), characterized in that, The valve body (2) is provided with a P oil inlet (8), an A working oil port (6), a B working oil port (3) and a T oil return port (23); the P oil inlet (8) is communicated with the switching valve cavity (22) through an oil inlet cavity, the B working oil port (3) is communicated with the switching valve cavity (22) through a first working cavity (31), the T oil return port (23) is communicated with the switching valve cavity (22) through an oil return cavity (24), and the A working oil port (6) is communicated with the switching valve cavity (22) through a second working cavity (61); a hydraulic lock (5) for controlling the on-off between the second working cavity (61) and the switching valve cavity (22) is arranged on the second working cavity (61); the valve body (2) is provided with a first bypass cavity (32) communicating the first working cavity (31) and the T oil return port (23), and a single-acting switch (4) capable of controlling the on-off between the first bypass cavity (32) and the T oil return port (23) is arranged on the first bypass cavity (32). When the valve rod (21) is in the first state, the oil inlet cavity, the first working cavity (31), the second working cavity (61) and the oil return cavity (24) are not communicated with each other; when the valve rod (21) is in the second state, the oil inlet cavity is communicated with the first working cavity (31) through the switching valve cavity (22), and the second working cavity (61) is communicated with the oil return cavity (24) through the switching valve cavity (22); when the valve rod (21) is in the third state, the oil inlet cavity is communicated with the second working cavity (61) through the switching valve cavity (22), and the first working cavity (31) is communicated with the oil return cavity (24) through the switching valve cavity (22).

2. The load sensing combination valve body of claim 1, wherein, The single-acting switch (4) comprises a switch cavity (47) arranged on the top of the valve body (2), the right end of the first bypass cavity (32) is communicated with the middle part of the switch cavity (47), the bottom end of the switch cavity (47) is communicated with the T oil return port (23), the top of the switch cavity (47) is fixedly installed with a mounting seat (41), the inner side of the mounting seat (41) is sleeved with a mounting column (42) capable of moving up and down, and the bottom of the mounting column (42) is fixedly installed with a plug (46) for plugging the switch cavity (47); when the single-acting switch (4) is in the closed state, the plug (46) is located in the switch cavity (47) below the first bypass cavity (32) and plugs it, and when the single-acting switch (4) is in the open state, the plug (46) is located in the upper part of the connection between the first bypass cavity (32) and the switch cavity (47), and the first bypass cavity (32) is communicated with the T oil return port (23) through the switch cavity (47).

3. The load sensing combination valve body of claim 2, wherein, The top of the mounting seat (41) is provided with an internal thread, and the top of the mounting column (42) is provided with an external thread; the mounting seat (41) and the mounting column (42) are matched through threads.

4. The load sensing combination valve body of claim 2, wherein, The mounting seat (41) and the valve body (2) are installed with a first sealing ring (43), the mounting column (42) and the mounting seat (41) are provided with a second sealing ring (44), and the plug (46) and the switch cavity (47) are provided with a third sealing ring (45).

5. The load sensing combination valve body of claim 1, wherein, The oil inlet cavity comprises a first oil inlet cavity (81) and a second oil inlet cavity (82), one end of the first oil inlet cavity (81) is communicated with the P oil inlet (8), the other end is communicated with the switching valve cavity (22), the second oil inlet cavity (82) is located on one side of the first oil inlet cavity (81), and both ends of the second oil inlet cavity (82) are communicated with the switching valve cavity (22); When the valve rod (21) is in the first state, the first oil inlet cavity (81) is not communicated with the second oil inlet cavity (82); when the valve rod (21) is in the second state, the first oil inlet cavity (81) is communicated with the second oil inlet cavity (82) and the first working cavity (31); when the valve rod (21) is in the third state, the first oil inlet cavity (81) is not communicated with the second oil inlet cavity (82), and the first oil inlet cavity (81) is communicated with the second working cavity (61).

6. The load sensing combination valve body of claim 2, wherein, The switching valve cavity (22) is sequentially provided with a first cavity (221) communicated with one end of the second oil inlet cavity (82), a second cavity (222) communicated with the first working cavity (31), a third cavity (223) communicated with the oil return cavity (24), a fourth cavity (224) communicated with the lower locking cavity (593), a fifth cavity (225) communicated with the other end of the second oil inlet cavity (82) and a sixth cavity (226) communicated with the first working cavity (31) from left to right; the valve rod (21) is provided with a first groove (211) capable of controlling the on-off of the first cavity (221) and the second cavity (222) and the second cavity (222) and the third cavity (223), a second groove (212) capable of controlling the on-off of the third cavity (223) and the fourth cavity (224) and the fourth cavity (224) and the fifth cavity (225), a third groove (213) capable of controlling the on-off of the fifth cavity (225) and the sixth cavity (226), and a fourth groove (214).

7. The load sensing combination valve body of claim 6, wherein, The hydraulic lock (5) comprises an upper locking cavity (58) and a lower locking cavity (593) arranged on the top of the valve body (2), the bottom of the upper locking cavity (58) is communicated with the left end of the second working cavity (61), the top of the lower locking cavity (593) is communicated with the left end of the second working cavity (61), a first valve core (54) capable of plugging the lower locking cavity (593) is slidably arranged in the upper locking cavity (58), a top seat (51) is fixedly arranged on the top of the upper locking cavity (58), a first spring (52) is fixedly connected to the bottom end of the top seat (51), the bottom end of the first spring (52) is fixedly connected with the first valve core (54), and a second valve core (57) capable of upwardly fixing the first valve core (54) is slidably arranged below the first valve core (54) of the valve body (2).

8. The load sensing combination valve body of claim 7, wherein, The bottom of the second valve core (57) is in contact with the bottom of the second groove (212), the bottom of the second valve core (57) is hemispherical, and the right side wall of the second groove (212) is inclined; when the valve rod (21) is in the first state, the bottom of the second valve core (57) is located at the bottom of the slope.

9. The load sensing combination valve body of claim 5, wherein, The valve body (2) is provided with a transversely arranged pressure compensation valve (7) below the valve rod (21), the pressure compensation valve (7) comprises a compensation valve cavity (73), a compensation valve core (71) capable of moving left and right is arranged in the compensation valve cavity (73), a third spring (72) is fixedly arranged at the leftmost end of the compensation valve cavity (73), and the rightmost end of the third spring (72) is fixedly connected with the compensation valve core (71); a P oil inlet (8) is in communication with the right part of the compensation valve cavity (73), the first working cavity (31) is in communication with the middle part of the compensation valve cavity (73) away from the valve rod (21), and the middle part of the second working cavity (61) is in communication with the left part of the compensation valve cavity (73).

10. The load sensing combination valve body of claim 1, wherein, The valve body (2) is provided with an overflow valve (63) above the valve rod (21), the second working cavity (61) is communicated with a second bypass cavity (62), and the second bypass cavity (62) is communicated with an overflow port (64) through the overflow valve (63).

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