Load-sensitive hydraulic control valve bank, tractor hydraulic system and tractor

Abstract

The invention belongs to the field of agricultural machinery, and discloses a load-sensitive hydraulic control valve bank, a tractor hydraulic system and a tractor. The load-sensitive hydraulic control valve set comprises a main valve which is connected with a main oil inlet oil way, a main oil return oil way and a load feedback oil way. The switch control valve is arranged in a communicating oil way of the main oil inlet oil way and the main oil return oil way; the switch control valve is arranged to disconnect the communicating oil way when the oil inlet oil pressure of the main oil inlet oil way is lower than the set oil inlet pressure, and control the oil inlet oil pressure to be in direct proportion to the real-time load oil pressure when the real-time load oil pressure of the load feedback oil way is larger than the first set load oil pressure. In a tractor hydraulic system, a metering pump is connected with a main oil inlet of a load-sensitive hydraulic control valve set, and oil is supplied to a main valve through a main oil inlet way. And the load-sensitive hydraulic control valve group can also be connected with an auxiliary hydraulic system. According to the constant displacement pump hydraulic system, combination of the constant displacement pump and the load-sensitive valve is achieved, the energy loss of the system is reduced, and a Power Beyond functional interface is additionally arranged for the constant displacement pump hydraulic system.

Description

Technical Field

[0001] The present application belongs to the field of agricultural machinery, and in particular, relates to a load-sensitive hydraulic control valve group, a tractor hydraulic system and a tractor. Background Art

[0002] Existing tractor hydraulic systems mostly use load-sensitive multi-way valves combined with variable piston pumps to adjust the pumping flow according to the load size. However, this flow control method has high requirements on the cleanliness of hydraulic oil and hydraulic feedback and calculation control, and requires the addition of more hydraulic valves, which will inevitably lead to more pressure control pipelines and the use of more expensive hydraulic valves, making the hydraulic system complicated and costly. Summary of the invention

[0003] The purpose of the present application is to provide a load-sensitive hydraulic control valve group, a tractor hydraulic system and a tractor, so as to realize the application of the load-sensitive hydraulic control valve group in the tractor quantitative hydraulic system and reduce the system cost.

[0004] To achieve the above objectives, the present application discloses a load-sensitive hydraulic control valve group in a first aspect, comprising:

[0005] A main valve is connected with a main oil inlet circuit, a main oil return circuit and a load feedback circuit;

[0006] A switch control valve is arranged in the connecting oil circuit between the main oil inlet circuit and the main oil return circuit;

[0007] Among them, the switch control valve is configured to disconnect the connecting oil circuit when the oil inlet pressure of the main oil inlet circuit is lower than the set oil inlet pressure, and when the real-time load oil pressure of the load feedback oil circuit is greater than the first set load oil pressure, control the oil inlet pressure to be proportional to the real-time load oil pressure.

[0008] In some embodiments, the switch control valve comprises:

[0009] The stop valve is a switch reversing valve including a first hydraulically controlled end and a second hydraulically controlled end, wherein the first hydraulically controlled end is hydraulically connected to the main oil inlet circuit, and the second hydraulically controlled end is provided with an end spring and is hydraulically connected to the load feedback circuit.

[0010] In some embodiments, the switch control valve comprises:

[0011] A logic valve, wherein one side oil port of the logic valve is hydraulically connected to the main oil inlet circuit and the first hydraulic control end of the stop valve, and the other side oil port is hydraulically connected to the load feedback circuit;

[0012] Wherein, the logic valve is a normally closed hydraulically controlled switch valve whose pilot oil port is hydraulically connected to the load feedback oil circuit, and is configured to switch to the on position when the real-time load oil pressure of the load feedback oil circuit is greater than the second set load oil pressure.

[0013] In some embodiments, the main valve includes a load feedback oil port and a first shuttle valve arranged in the load feedback oil circuit, the first comparison oil port of the first shuttle valve is hydraulically connected to the load feedback oil circuit on one side of the main valve, and the second comparison oil port is hydraulically connected to the load feedback oil port, and the oil outlet of the first shuttle valve is hydraulically connected to the load feedback oil circuit on one side of the switch control valve.

[0014] In some embodiments, the load-sensing hydraulic control valve group includes a throttling damper, and the throttling damper is arranged in a connecting oil circuit between the load feedback oil port and the main oil return oil circuit.

[0015] In some embodiments, the load-sensitive hydraulic control valve group includes a second shuttle valve, a first comparison oil port of the second shuttle valve is hydraulically connected to the load feedback oil circuit on one side of the main valve, and the second comparison oil port is hydraulically connected to the main return oil circuit, and an oil outlet of the second shuttle valve is hydraulically connected to the first comparison oil port of the first shuttle valve.

[0016] In some embodiments, the load-sensitive hydraulic control valve group includes a pressure compensator for controlling the output flow of the main valve; and / or, the main valve is a sliding valve; and / or, the load-sensitive hydraulic control valve group includes a safety valve connected between the main oil inlet circuit and the main oil return circuit.

[0017] A second aspect of the present application discloses a tractor hydraulic system, the tractor hydraulic system comprising:

[0018] The load sensing hydraulic control valve group mentioned above;

[0019] A metering pump is connected to the main oil inlet of the load-sensing hydraulic control valve group and supplies oil to the main valve through the main oil inlet oil circuit.

[0020] In some embodiments, the tractor hydraulic system comprises:

[0021] The auxiliary hydraulic system comprises a variable displacement pump, and the auxiliary hydraulic system is detachably hydraulically connected to the main oil inlet circuit, the main oil return circuit and the load feedback circuit of the load-sensitive hydraulic control valve group through a quick-change joint.

[0022] A third aspect of the present application discloses a tractor, characterized in that the tractor comprises the above-mentioned tractor hydraulic system.

[0023] In the load-sensitive hydraulic control valve group, tractor and tractor hydraulic system of the present application, a switch control valve is added to the load-sensitive hydraulic control valve group, and the switch control valve is set in the connecting oil circuit between the main oil inlet oil circuit and the main oil return oil circuit. When the output oil port of the main valve is basically unloaded, the main oil inlet oil circuit and the main oil return oil circuit are disconnected, and the system is in a low-pressure unloading state with a small pressure loss. When there is a load condition, the switch control valve is used to control the oil inlet pressure to change in proportion to the real-time load oil pressure, so that the system pressure meets the load usage requirements, thereby realizing the function of the quantitative pump controlling the load-sensitive valve, realizing the application of the load-sensitive hydraulic control valve group in the tractor quantitative hydraulic system, and reducing the system cost.

[0024] Other advantages of the present application and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide an understanding of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present application but do not constitute a limitation to the present application. In the accompanying drawings:

[0026] Figure 1 A hydraulic principle diagram of a load sensing hydraulic control valve group according to a specific embodiment of the present application; and

[0027] Figure 2 The hydraulic principle diagram of the tractor hydraulic system according to the specific implementation mode of the present application.

[0028] Description of Reference Numerals

[0029] 1 Tool hydraulic motor and control device 2 Suction filter

[0030] 3 Power unit 4 Dosing pump

[0031] 6 Load sensing hydraulic control valve group 5 Quick change connector

[0032] 7 Return oil filter 8 Hydraulic oil tank

[0033] 601 Safety valve 602 Chassis control valve group

[0034] 603 First shuttle valve 604 Second shuttle valve

[0035] 605 Pressure compensator 606 Main valve

[0036] 607 Logic valve 608 Shut-off valve

[0037] 609 Pressure reducing valve 610 Filter

[0038] P1 First main oil inlet P2 Second main oil inlet

[0039] T1 First main oil return port T2 Second main oil return port

[0040] LS Load feedback oil circuit LS1 Load feedback oil port

[0041] P Main oil inlet circuit T Main oil return circuit

[0042] A Machine oil inlet L Connecting oil circuit DETAILED DESCRIPTION

[0043] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present application and is not intended to limit the present application. It should be noted that, in the absence of conflict, the implementations in the present application and the features in the implementations can be combined with each other.

[0044] The load-sensing hydraulic control valve group, the tractor and the tractor hydraulic system thereof of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0045] In order to realize the application of load-sensitive hydraulic control valve group in tractor quantitative hydraulic system, the present application discloses a new type of load-sensitive hydraulic control valve group. Figure 1 , Figure 2 As shown, in a specific embodiment, the load-sensing hydraulic control valve group 6 includes:

[0046] The main valve 606 is connected with the main oil inlet circuit P, the main oil return circuit T and the load feedback circuit LS;

[0047] The switch control valve is arranged in the connecting oil passage L between the main oil inlet oil passage P and the main oil return oil passage T;

[0048] Among them, the switch control valve is set to disconnect the connecting oil circuit L when the oil pressure of the main oil inlet circuit P is lower than the set oil inlet pressure, and when the real-time load oil pressure of the load feedback oil circuit LS is greater than the first set load oil pressure, the control oil inlet pressure is proportional to the real-time load oil pressure.

[0049] In the load-sensitive hydraulic control valve group 6 of the present application, a normally-off switch control valve is provided in the connecting oil path L between the main oil inlet oil path P and the main oil return oil path T, so that Figure 1The load feedback oil circuit LS shown by the middle dotted line is in no-load feedback or low-load feedback, that is, when there is basically no load, there is no connection between the main oil inlet oil circuit P and the main oil return oil circuit T, so that the system is in a low-pressure unloading state, and the oil inlet pressure of the main oil inlet oil circuit P is lower than the set oil inlet pressure, and the pressure loss is small. In the load condition, that is, when the real-time load oil pressure of the load feedback oil circuit LS is greater than the first set load oil pressure, the switch control valve is used to control the oil inlet pressure to be proportional to the real-time load oil pressure, that is, the system pressure is controlled so that the system pressure meets the load usage requirements. On this basis, the function of the quantitative pump controlling the load sensitive valve can be realized.

[0050] Comparably, variable piston pumps are mostly used in the prior art, so the load-sensitive hydraulic control valve feeds back the load information to the variable piston pump in the form of load feedback oil, thereby adjusting the pumping flow to adapt to load changes. Among them, the variable piston pump is more complex and expensive than the gear pump used as a quantitative pump. When the variable piston pump is far away from the main valve, the pipeline layout is complicated, and the feedback timeliness is poor. The cleanliness of the oil is required to be higher, otherwise the feedback oil with poor cleanliness may cause blockage and pressure loss, resulting in poor feedback effect and delay. In addition, in order to achieve more accurate change control, more control valves need to be designed, such as setting a complex flow control valve inside the variable piston pump. In contrast, the load-sensitive hydraulic control valve group 6 of the present application can realize the combination of the load-sensitive valve and the quantitative pump by integrating and designing a simple switch control valve, and the path of the load feedback oil channel is shorter, the cleanliness of the oil is lower, and the feedback timeliness is stronger.

[0051] It should be noted that the above-mentioned set oil inlet pressure and the first set load oil pressure can be specifically set according to different use environments, different valve types and structures. Figure 1 In the embodiment, the set oil inlet pressure can be set to the spring force of the end spring at the lower end of the stop valve 608, and the first set load oil pressure can also be set to zero. Of course, the present application is not limited to this.

[0052] Those skilled in the art will appreciate that the normally-off switch control valve provided in the connecting oil path L between the main oil inlet oil path P and the main oil return oil path T may adopt the structure of an electrically controlled switch valve, and the control function of the switch control valve may be realized by the electrically controlled structure. Figure 1 The switch control valve shown is in the form of a hydraulically operated valve.

[0053] As an example, Figure 1 The switch control valve shown includes a stop valve 608, which includes a first hydraulic control end (i.e. Figure 1 The upper end of the valve shown) and the second hydraulic control end (i.e. Figure 1The lower end of the valve shown in the figure) is a switch reversing valve, the first hydraulic control end is hydraulically connected to the main oil inlet circuit P, and the second hydraulic control end is provided with an end spring and is hydraulically connected to the load feedback oil circuit LS.

[0054] Among them, the stop valve 608 is used as a hydraulically controlled switch valve, and the pressure signal acts on both ends of the valve core. The upper position of the stop valve 608 shown in the figure is hydraulically connected to the main oil inlet oil circuit P, and the lower position is connected to the main valve feedback pressure, that is, the hydraulic connection load feedback oil circuit LS. When there is no load acting on the main valve 606, the stop valve 608 is only subject to the spring force of the end spring at the lower end and the control pressure (that is, the system pressure, that is, the oil inlet pressure of the main oil inlet oil circuit P) at the upper end of the stop valve. When the system pressure of the main oil inlet oil circuit P exceeds the spring force, the main oil inlet oil circuit P is connected with the main return oil circuit T through the connecting oil circuit L, and then returns to the hydraulic oil tank 8 through the return oil filter 7. At this time, the system pressure is the spring force of the end spring of the stop valve 608. When there is a load action, the pressure signal is transmitted to the lower end of the stop valve 608 through the load feedback oil circuit LS until the system pressure reaches a balance with the spring force and the load pressure, and the system pressure fluctuates in direct proportion to the load.

[0055] Figure 1 The switch control valve may also include a logic valve 607, one side oil port of the logic valve 607 is hydraulically connected to the main oil inlet circuit P and the first hydraulic control end of the stop valve 608, and the other side oil port is hydraulically connected to the load feedback oil circuit LS; wherein the logic valve 607 is a normally closed hydraulically controlled switch valve whose pilot oil port is hydraulically connected to the load feedback oil circuit LS, and is configured to switch to the on position when the real-time load oil pressure of the load feedback oil circuit LS is greater than the second set load oil pressure.

[0056] Among them, the logic valve 607 and the stop valve 608 are both normally closed hydraulically controlled switching valves. The main function of the logic valve 607 is to improve the feedback response speed. When the load exceeds a certain pressure, the load pressure acts on the lower end of the logic valve 607 shown in the figure, and the logic valve 607 switches to the lower position. The pressure oil in the load feedback oil circuit LS is filled to the main oil inlet circuit P, the stop valve 608 and other valve components, so that the system is quickly filled with hydraulic oil.

[0057] In order to connect to other hydraulic systems externally, the main valve 606 may further include a load feedback oil port LS1 and a first shuttle valve 603 disposed in the load feedback oil circuit LS, wherein the first comparison oil port of the first shuttle valve 603 is hydraulically connected to the load feedback oil circuit LS on one side of the main valve 606, and the second comparison oil port is hydraulically connected to the load feedback oil port LS1, and the oil outlet of the first shuttle valve 603 is hydraulically connected to the load feedback oil circuit LS on one side of the switch control valve. In other words, after the feedback oil of the load feedback oil circuit LS drawn from the main valve 606 and the feedback oil of the external load feedback oil port LS1 are compared by the pressure of the first shuttle valve 603, the one with the larger pressure flows out from the oil outlet of the first shuttle valve 603 to the load feedback oil circuit LS on one side of the stop valve 608.

[0058] Among them, the first shuttle valve 603 is mainly composed of a control spring and a steel ball, and is built into the load-sensitive hydraulic control valve group 6. It has the functions of a traditional shuttle valve and adds the function of priority of the control feedback signal pressure of the main valve 606, thereby avoiding the phenomenon of slow pressure relief or failure to relieve pressure during the control pressure unloading process of the logic valve 607 and the stop valve 608.

[0059] The load-sensitive hydraulic control valve group 6 may further include a throttle damper 602, which is disposed in the connecting oil circuit between the load feedback oil port LS1 and the main oil return oil circuit T. The throttle damper 602 plays a throttling role on the one hand, so that the load feedback oil port LS1 can establish feedback pressure, and on the other hand, it discharges the pressure leaked from the first shuttle valve 603 to the load feedback oil port LS1 connected to other external hydraulic systems, thereby preventing the first shuttle valve 603 from jumping and the load feedback pipeline of the main valve 606 from being blocked due to a sudden drop in pressure, and has the function of protecting the pressure signal.

[0060] The load-sensing hydraulic control valve group 6 may further include a second shuttle valve 604, a first comparison oil port of the second shuttle valve 604 is hydraulically connected to the load feedback oil circuit LS on one side of the main valve 606, and a second comparison oil port is hydraulically connected to the main return oil circuit T, and an oil outlet of the second shuttle valve 604 is hydraulically connected to the first comparison oil port of the first shuttle valve 603. The control system of the second shuttle valve 604 has the functions of pressure comparison and rapid unloading of the feedback oil circuit.

[0061] See also Figure 1 The load-sensitive hydraulic control valve group 6 may also include a pressure compensator 605 for controlling the output flow of the main valve 606; the main valve 606 is a slide valve, which adopts a bus-controlled slide valve structure, and the valve core opening is controllable to achieve adjustable flow. The pressure compensator 605 is a pre-valve pressure compensator of the main valve 606, and forms a speed regulating mechanism with the main valve 606, which can achieve the adjustable output flow output from the tool oil inlet A. The load-sensitive hydraulic control valve group 6 also includes a safety valve 601 connected between the main oil inlet circuit P and the main oil return circuit T. The safety valve 601 is an overflow structure, which controls the upper limit of the system pressure and plays a role in protecting the hydraulic components. Figure 1 The pressure reducing valve 609 in the main valve 606 mainly provides control pressure for the main valve 606; the filter 610 mainly ensures the cleanliness of the pressure oil entering the main valve 606, meets the use requirements of the main valve core, and avoids valve sticking and other phenomena.

[0062] On this basis, the present application also discloses a tractor hydraulic system. Figure 2 As shown, in a specific embodiment, the tractor hydraulic system includes:

[0063] The load sensing hydraulic control valve group 6 according to the present application;

[0064] The metering pump 4 is connected to the main oil inlet of the load-sensing hydraulic control valve group 6 and supplies oil to the main valve 606 through the main oil inlet oil circuit P1.

[0065] It can be seen that the tractor hydraulic system includes a metering pump system, which realizes the metering pump 4 controlling the load-sensitive hydraulic control valve group 6. The metering pump 4 sucks the hydraulic oil from the hydraulic oil tank 8 under the action of the power device 3; the hydraulic oil flows back to the hydraulic oil tank 8 after passing through the suction filter 2, the metering pump 4, the load-sensitive hydraulic control valve group 6, and the return filter 7 in sequence, and the system pressure is controlled by the load-sensitive hydraulic control valve group 6. The suction filter 2 and the return filter 7 also ensure that the cleanliness of the hydraulic system meets the working conditions of the hydraulic components.

[0066] In particular, the tractor hydraulic system of this embodiment includes:

[0067] The auxiliary hydraulic system includes a variable displacement pump, and the auxiliary hydraulic system is detachably hydraulically connected to a main oil inlet circuit P, a main oil return circuit T and a load feedback circuit LS of a load-sensitive hydraulic control valve group 6 through a quick-change joint 5 .

[0068] In this application, the main hydraulic system has a Power Beyond function interface, that is, the load-sensing hydraulic control valve group 6 adds an auxiliary hydraulic system interface, which can directly provide a pressure source, a return oil port and other control oil ports to the tractor's implement system. Figure 2 The main oil inlet of the load-sensitive hydraulic control valve group 6 includes a first main oil inlet P1 and a second main oil inlet P2 connected in parallel to the main oil inlet oil circuit P. The main oil return port of the load-sensitive hydraulic control valve group 6 includes a first main oil return port L1 and a second main oil return port L2 connected in parallel to the main oil return oil circuit T. The load-sensitive hydraulic control valve group 6 also includes an external load feedback oil port LS1, which is mainly used to transmit pressure signals. The first main oil inlet P1 and the second main oil inlet P2, the first main oil return port L1 and the second main oil return port L2 adopt a parallel oil port structure, which can realize the simultaneous supply of oil to the main hydraulic system and the auxiliary hydraulic system. The oil outlet of the metering pump 4 is hydraulically connected to the first main oil inlet P1, and the oil inlet of the variable pump of the auxiliary hydraulic system is connected to the second main oil inlet P2.

[0069] Figure 2 In the figure, the tool hydraulic motor and control device 1 is taken as an example, which is connected to the load-sensitive hydraulic control valve group 6 through the quick-change joint 5 as an auxiliary hydraulic system. The tool hydraulic motor and control device 1 mainly includes: a hydraulic motor, a directional control valve, a three-way speed regulating valve and a quick-change joint 5, etc. The quick-change joint 5 connects the tool hydraulic system and the host hydraulic system to realize the Power Beyond function of the host hydraulic system.

[0070] exist Figure 2In the tractor hydraulic system shown, when the main valve 606 is not working, the hydraulic oil returns to the hydraulic oil tank 8 after passing through the main valve 606. At this time, the system pressure is controlled by the spring in the valve (i.e., the end spring of the stop valve 608) and the pressure is very low, and the system loss is very small. When the main valve 606 is not working, the quick-change connector 5 connects the tool hydraulic motor and control device 1 with the load-sensitive hydraulic control valve group 6, and the system pressure changes with the pressure of the tool hydraulic motor and control device 1, so that the system does not always work under the highest pressure state, which helps to extend the service life of the hydraulic components. When the main valve 606 is working, the system pressure changes with the load and the output flow can be controlled. When the main valve 606 and the tool hydraulic motor and control device 1 are working at the same time, the system pressure depends on the sum of the maximum load pressure and the control pressure of the built-in spring of the control valve.

[0071] In addition, the present application also protects a tractor, which includes a tractor hydraulic system according to the present application. The tractor of the present application realizes the combination of a metering pump and a load-sensitive valve, reduces the energy loss of the system, and also adds a Power Beyond function interface to the metering pump hydraulic system. Among them, through the switch control valve added in the load-sensitive hydraulic control valve group 6, the function of the metering pump controlling the load-sensitive hydraulic control valve group 6 can be realized, and under no-load conditions, the system is in a low-pressure unloading state with less pressure loss; under load conditions, the switch control valve controls the system pressure so that the system pressure meets the load usage requirements. By adding the first shuttle valve 603, it has both the pressure transmission function of the traditional shuttle valve and can give priority to the transmission of a certain pressure control signal, and has the function of fast unloading. In addition, a throttling damping 602 is added to the pressure feedback signal oil circuit of the auxiliary hydraulic system, which can ensure the establishment of the load signal and realize the standby pressure unloading, and has the function of preventing the occurrence of problems such as system pressure holding.

[0072] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0073] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0074] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0075] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A load-sensitive hydraulic control valve group, characterized in that: The load-sensing hydraulic control valve group (6) comprises: A main valve (606) is connected to a main oil inlet circuit (P), a main oil return circuit (T) and a load feedback circuit (LS); A switch control valve is arranged in the connecting oil circuit (L) between the main oil inlet circuit (P) and the main oil return circuit (T); Wherein, the switch control valve is configured to disconnect the connecting oil circuit (L) when the inlet oil pressure of the main oil inlet circuit (P) is lower than the set inlet oil pressure, and when the real-time load oil pressure of the load feedback oil circuit (LS) is greater than the first set load oil pressure, control the inlet oil pressure to be proportional to the real-time load oil pressure.

2. The load-sensing hydraulic control valve assembly according to claim 1, characterized in that: The switch control valve comprises: A stop valve (608), the stop valve (608) is a switch reversing valve including a first hydraulically controlled end and a second hydraulically controlled end, the first hydraulically controlled end is hydraulically connected to the main oil inlet circuit (P), and the second hydraulically controlled end is provided with an end spring and is hydraulically connected to the load feedback circuit (LS).

3. The load-sensing hydraulic control valve assembly according to claim 2, characterized in that: The switch control valve comprises: A logic valve (607), wherein one side oil port of the logic valve (607) is hydraulically connected to the main oil inlet circuit (P) and the first hydraulic control end of the stop valve (608), and the other side oil port is hydraulically connected to the load feedback circuit (LS); Among them, the logic valve (607) is a normally closed hydraulically controlled switching valve whose pilot oil port is hydraulically connected to the load feedback oil circuit (LS), and is configured to switch to the on position when the real-time load oil pressure of the load feedback oil circuit (LS) is greater than the second set load oil pressure.

4. The load-sensing hydraulic control valve assembly according to any one of claims 1 to 3, characterized in that: The main valve (606) includes a load feedback oil port (LS1) and a first shuttle valve (603) arranged in the load feedback oil circuit (LS), the first comparison oil port of the first shuttle valve (603) is hydraulically connected to the load feedback oil circuit (LS) on one side of the main valve (606), and the second comparison oil port is hydraulically connected to the load feedback oil port (LS1), and the oil outlet of the first shuttle valve (603) is hydraulically connected to the load feedback oil circuit (LS) on one side of the switch control valve.

5. The load-sensing hydraulic control valve assembly according to claim 4, characterized in that: The load-sensitive hydraulic control valve group (6) comprises a throttle damper (602), and the throttle damper (602) is arranged in a connecting oil circuit between the load feedback oil port (LS1) and the main oil return oil circuit (T).

6. The load-sensing hydraulic control valve assembly according to claim 5, characterized in that: The load-sensitive hydraulic control valve group (6) includes a second shuttle valve (604), a first comparison oil port of the second shuttle valve (604) is hydraulically connected to the load feedback oil circuit (LS) on one side of the main valve (606), and the second comparison oil port is hydraulically connected to the main return oil circuit (T), and an oil outlet of the second shuttle valve (604) is hydraulically connected to the first comparison oil port of the first shuttle valve (603).

7. The load sensing hydraulic control valve assembly according to claim 1, characterized in that: The load-sensitive hydraulic control valve group (6) includes a pressure compensator (605) for controlling the output flow of the main valve (606); and / or, the main valve (606) is a sliding valve; and / or, the load-sensitive hydraulic control valve group (6) includes a safety valve (601) connected between the main oil inlet circuit (P) and the main oil return circuit (T).

8. A tractor hydraulic system, characterized in that: The tractor hydraulic system comprises: A load-sensing hydraulic control valve assembly (6) according to any one of claims 1 to 7; The metering pump (4) is connected to the main oil inlet of the load-sensitive hydraulic control valve group (6) and supplies oil to the main valve (606) through the main oil inlet oil circuit (P1).

9. The tractor hydraulic system according to claim 8, characterized in that: The tractor hydraulic system comprises: The auxiliary hydraulic system comprises a variable displacement pump, wherein the auxiliary hydraulic system is detachably hydraulically connected to the main oil inlet circuit (P), the main oil return circuit (T) and the load feedback circuit (LS) of the load-sensitive hydraulic control valve group (6) via a quick-change joint (5).

10. A tractor, characterized in that: The tractor comprises a tractor hydraulic system according to any one of claims 8 or 9.

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