Electromagnetic valve group for tractor

Abstract

The electromagnetic valve group for the tractor comprises a valve block, an oil supply channel, an oil return channel, a switching valve, a motor control valve and an oil cylinder control valve are arranged on the valve block, the oil supply channel is connected with the switching valve, a first outlet of the switching valve is connected with a pressure oil port of the motor control valve, and an oil return port of the motor control valve is connected with the oil return channel; a second outlet of the switching valve is connected with a pressure oil port of the oil cylinder control valve, and an oil return port of the oil cylinder control valve is connected with the oil return channel. When the tractor is switched to perform combined operation, the required working motor is connected through the motor control valve, the required working oil cylinder is connected through the oil cylinder control valve, and the working state of the switching valve is changed, so that a matched hydraulic system does not need to be replaced, the operation is convenient, a common user can efficiently complete the operation, the use cost is low, and the working efficiency is high. And popularization and application of diversified tools of the tractor are facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of tractor implement hydraulic systems, in particular to a solenoid valve group for tractors. Background Art

[0002] Through integration with various implements, the application scope of tractors continues to expand, broadening the market for tractors as main machines. The emergence and deployment of increasingly diverse implements, such as weeding, pruning, spraying, tilling, and traction, has placed higher demands on tractors as main machines. Implements, as auxiliary working devices attached to the tractor, come in various configurations, including cylinder-controlled and motor-controlled, and their functionality is becoming increasingly diverse.

[0003] Currently, when a tractor needs to operate with different types of implements, it's necessary to switch between different drive systems to power the implements. Different drive systems use different hydraulic oil supply methods. For example, cylinders supply oil in a round trip with a limited amount per trip, while motors provide oil in a single trip with a continuous supply. Therefore, switching drives often requires replacing the supporting hydraulic system, a cumbersome operation that requires a high level of expertise, limiting the widespread adoption of diverse tractor implements. Utility Model Content

[0004] The technical problem to be solved by the utility model is: when a tractor switches an implement combination operation, how to quickly switch a driving device of a corresponding form to improve the switching efficiency.

[0005] The technical solution of the utility model to solve the above technical problems is as follows:

[0006] The utility model provides a solenoid valve group for a tractor, comprising a valve block, wherein the valve block is provided with an oil supply channel, an oil return channel, a switching valve, a motor control valve and a cylinder control valve, the oil supply channel is connected to the switching valve, a first outlet of the switching valve is connected to a pressure oil port of the motor control valve, and an oil return port of the motor control valve is connected to the oil return channel; a second outlet of the switching valve is connected to a pressure oil port of the cylinder control valve, and an oil return port of the cylinder control valve is connected to the oil return channel.

[0007] The beneficial effects of the utility model are:

[0008] With this utility model, when a tractor switches between combined implement operations, depending on the implement's desired cylinder drive, motor drive, or combined drive, it only needs to connect the required working motor through the motor control valve, connect the required working cylinder through the cylinder control valve, and change the operating state of the switching valve. This eliminates the need to replace the supporting hydraulic system, making operation convenient and efficient for ordinary users. The low cost of use facilitates the widespread application of diversified tractor implements. Specifically, the switching valve controls the flow of pressurized oil in the oil supply channel, enabling independent or simultaneous oil supply to the motor control valve and the cylinder control valve. The motor control valve can be used to control the start / stop and operating direction of the working motor, while the cylinder control valve can be used to control the extension or retention of the working cylinder, thus achieving independent control of the working motor and the working cylinder.

[0009] On the basis of the above technical solution, the present invention can also be improved as follows.

[0010] Furthermore, it also includes an unloading valve, the inlet of the unloading valve is connected to the oil supply channel, and the outlet of the unloading valve is connected to the oil return channel.

[0011] When the motor and cylinder are moving, if the sudden change of external load causes a sharp fluctuation in pressure, the unloading valve can be opened at this time, and the pressure oil will be directly returned to the return oil channel through the unloading valve, thereby achieving the purpose of limiting the pressure and protecting the hydraulic system.

[0012] Furthermore, one end of the valve core of the unloading valve is connected to its own inlet oil circuit, and the direction of the oil pressure from its own inlet oil circuit on the valve core of the unloading valve is opposite to the direction of the reset elastic force of the valve core; the unloading valve is a normally closed valve.

[0013] When the pressure in the oil supply channel fluctuates violently, the oil pressure can be used to automatically push the unloading valve to open, thereby achieving the purpose of limiting the pressure with good sensitivity.

[0014] Furthermore, it also includes a pilot oil circuit and a pilot safety valve, one end of the pilot oil circuit is connected to the oil supply channel, the other end of the pilot oil circuit is connected to the inlet end of the pilot safety valve through a first branch, the outlet end of the pilot safety valve is connected to the return oil channel, and one end of the valve core of the pilot safety valve is connected to its own inlet oil circuit; the other end of the pilot oil circuit is connected to the other end of the valve core of the unloading valve through a second branch; and a first throttling element is provided on the pilot oil circuit.

[0015] When overpressure occurs, the pilot safety valve can automatically control the unloading valve to open, thereby limiting the pressure and improving safety. When the pressure recovers, the pilot safety valve and the unloading valve can automatically reset, ensuring the stable operation of the hydraulic system and good reliability. During normal operation, the oil pressures at both ends of the valve core of the unloading valve are balanced with each other and are not affected by the pressure of the oil supply channel. It can adapt to any working pressure and has good adaptability.

[0016] Furthermore, the valve block is also provided with a first pressure measuring oil circuit, a second pressure measuring oil circuit and a third pressure measuring oil circuit. The first pressure measuring oil circuit is connected to the oil supply channel, the second pressure measuring oil circuit is connected to the second branch, and the third pressure measuring oil circuit is connected to the oil circuit of the working B port of the motor control valve.

[0017] By connecting the pressure measuring element through the first pressure measuring oil circuit and the second pressure measuring oil circuit, it is convenient to monitor the oil pressure at both ends of the valve core of the unloading valve, thereby judging the working status of the unloading valve and the pilot safety valve and detecting faults; by connecting the pressure measuring element through the third pressure measuring oil circuit, it is convenient to monitor the working B port pressure of the motor control valve, thereby judging the working status of the motor control valve and detecting faults; thereby improving the controllability of the hydraulic system.

[0018] Furthermore, it also includes a cylinder safety valve, the inlet of the cylinder safety valve is connected to the oil circuit of the second outlet of the switching valve, and the outlet of the cylinder safety valve is connected to the oil return channel.

[0019] When only the pressure of the working cylinder fluctuates violently, the cylinder safety valve limits the pressure from the second outlet of the switching valve to the cylinder control valve, thereby improving the stability and safety of the working cylinder and avoiding the impact on the working motor.

[0020] Furthermore, the switching valve is provided with a first inlet and a second inlet, the oil supply channel connects the first inlet and the second inlet of the switching valve through a branch, and a second throttling element is provided on the oil circuit of the second inlet; the first outlet of the switching valve corresponds to the first inlet, and the second outlet of the switching valve corresponds to the second inlet.

[0021] It is convenient to make the first outlet and the second outlet of the switching valve have independent passages, which has good reliability; under the action of the second throttling element, it is convenient to limit the oil supply speed of the working cylinder, avoid the working cylinder from moving too fast and causing collision when the oil pressure is high, and improve stability.

[0022] Furthermore, one end of the valve core of the switching valve is connected to the oil circuit of its first inlet, and the other end of the valve core of the switching valve is connected to the oil circuit of its second inlet.

[0023] Under the action of the second throttling element, when oil is discharged from the second outlet of the switching valve, there is a pressure difference at both ends of the valve core of the switching valve, and the pressure difference is proportional to the flow rate of the second outlet; when the cylinder is in working state, if the working cylinder moves too fast, the pressure difference at both ends of the valve core of the switching valve increases, and pushes the valve core of the switching valve to move to the first outlet to discharge oil, so as to facilitate the return of part of the pressurized oil to the return oil channel, avoid collision caused by excessive movement of the working cylinder, and improve the safety of the working cylinder.

[0024] Furthermore, the valve core of the motor control valve is provided with an oil return position and a motor position. When the oil return position is working, the pressure oil port, working port A and working port B of the motor control valve are all connected to their own oil return port; when the motor position is working, one of the working port A and working port B of the motor control valve is connected to its own pressure oil port, and the other is connected to its own oil return port; the normal state of the motor control valve is that it works in the oil return position.

[0025] When the working motor is not working, it is convenient to relieve the pressure of the hydraulic oil circuit where the working motor is located, and at the same time, the oil from the first outlet of the switching valve is directly returned to the return oil channel, avoiding affecting the working motor and improving safety.

[0026] Furthermore, the cylinder control valve is provided with multiple ones, the pressure oil port of the first cylinder control valve is connected to the second outlet of the switching valve, the pressure oil ports of the remaining cylinder control valves are connected to the return oil ports of their previous cylinder control valves, and the return oil port of the last cylinder control valve is connected to the return oil channel.

[0027] It is convenient to provide interfaces for multiple working cylinders, which can drive multiple working cylinders to extend and retract synchronously, thereby improving the load capacity. At the same time, when the cylinder load required by the machine is small, the rear half of the cylinder control valve can be switched to the oil return state, and the pressure oil port of the rear half of the cylinder control valve is connected to its own oil return port, thereby allowing part of the working cylinder to move, which has good flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the three-dimensional structure of the utility model.

[0029] Figure 2 for Figure 1 Schematic diagram of the three-dimensional structure from the left view direction.

[0030] Figure 3 This is a schematic diagram of the initial state of the utility model.

[0031] Figure 4 This is a schematic diagram of the motor working state of the present invention.

[0032] Figure 5 This is a schematic diagram of the working state of the oil cylinder of the present utility model.

[0033] Figure 6 This is a schematic diagram of the motor and cylinder in the present utility model in a combined working state.

[0034] Figure 7 This is a schematic diagram of the safe unloading state of the utility model.

[0035] In the accompanying drawings, the technical features represented by the reference numerals are as follows:

[0036] 1-valve block; 2-oil supply channel; 3-oil return channel; 4-switching valve; 5-motor control valve; 6-working motor; 7-cylinder control valve; 8-working cylinder; 9-unloading valve; 10-pilot safety valve; 11-first throttling element; 12-cylinder safety valve; 13-second throttling element; 14-first pressure measuring oil circuit; 15-second pressure measuring oil circuit; 16-third pressure measuring oil circuit; 17-main control valve. DETAILED DESCRIPTION

[0037] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0038] This utility model refers to Figure 1-7 .

[0039] The utility model provides a solenoid valve group for a tractor, comprising a valve block 1, on which an oil supply channel 2, an oil return channel 3, a switching valve 4, a motor control valve 5 and a cylinder control valve 7 are provided. The oil supply channel 2 is connected to the switching valve 4, a first outlet of the switching valve 4 is connected to a pressure oil port of the motor control valve 5, and an oil return port of the motor control valve 5 is connected to the oil return channel 3; a second outlet of the switching valve 4 is connected to a pressure oil port of the cylinder control valve 7, and an oil return port of the cylinder control valve 7 is connected to the oil return channel 3.

[0040] principle:

[0041] During installation, the oil supply channel 2 is connected to the pressure oil outlet of the main control valve 17 on the tractor, and the oil return channel 3 is connected to the return oil inlet of the main control valve 17. The main control valve 17 is a prior art component on the tractor. The pressure oil inlet of the main control valve 17 is connected to a pressure oil source such as a hydraulic pump, and the return oil outlet of the main control valve 17 is connected to the oil tank. When the tractor external implement needs to be driven by the working motor 6, the working port A and the working port B of the motor control valve 5 are respectively connected to the two ends of the working motor 6. When the tractor external implement needs to be driven by the working cylinder 8, the working port A and the working port B of the cylinder control valve 7 are respectively connected to the two ends of the working cylinder 8; the two ends of the working cylinder 8, namely the cylinder body end and the piston rod end, when the cylinder body end is filled with oil, the cylinder extends, and when the piston rod end is filled with oil, the cylinder shortens.

[0042] Note: Switching valve 4, motor control valve 5, and cylinder control valve 7 are all directional valves. The common nomenclature for directional valve connections is port A (working port A), port B (working port B), port P, and port T. Generally, ports A and B are working oil ports, used to connect to the hydraulic components they control; port P is the pressure oil port, for pressurized oil to enter; and port T is the return oil port, for oil to return. The directional valve operates in specific positions through the movement of its spool, creating specific connections between ports A, B, P, and T through specific positions, thereby changing the valve's operating state.

[0043] After being installed in the hydraulic system, it has the following status, such as Figure 3-7 As shown (the arrow direction is the oil flow direction): In the initial state, Figure 3 As shown, switching valve 4 is discharging oil from its first outlet. The pressure oil port, working port A, and working port B of motor control valve 5 are all connected to the oil return port. After pressure oil enters switching valve 4, it flows as follows: switching valve 4's first outlet → motor control valve 5's pressure oil port → motor control valve 5's oil return port → oil return channel 3.

[0044] When the motor is working, Figure 4 As shown, switching valve 4 is discharging oil from its first outlet. One of motor control valve 5's working ports A and B is connected to its own pressure port, while the other is connected to its own return port. After pressure oil enters switching valve 4, the flow path is: switching valve 4's first outlet → motor control valve 5's pressure port → motor control valve 5's working ports B / A → working motor 6 → motor control valve 5's working ports A / B → motor control valve 5's return port → return oil passage 3.

[0045] When the cylinder is working, Figure 5 As shown, switching valve 4 is in the oil-discharging state at its second outlet. One of cylinder control valve 7's working ports A and B is connected to its own pressure port, while the other is connected to its own return port. After pressure oil enters switching valve 4, it flows along the following path: switching valve 4's second outlet → cylinder control valve 7's pressure port → cylinder control valve 7's working ports B / A → working cylinder 8 → cylinder control valve 7's working ports A / B → cylinder control valve 7's return port → return oil passage 3.

[0046] When the motor and cylinder are in composite working state, Figure 6 As shown, the switching valve 4 is in a state where the first outlet and the second outlet simultaneously discharge oil. After the pressure oil enters the switching valve 4, the flow path of the motor working state and the flow path of the cylinder working state coexist.

[0047] With this utility model, when a tractor switches between combined implement operations, depending on the implement's desired cylinder drive, motor drive, or combined drive, the operator simply connects the required working motor 6 via the motor control valve 5, connects the required working cylinder 8 via the cylinder control valve 7, and changes the operating state of the switching valve 4. This eliminates the need to replace the associated hydraulic system, making operation convenient and efficient for even ordinary users. The low cost of use facilitates the widespread adoption of diverse tractor implements. Specifically, the switching valve 4 controls the flow of pressurized oil in the oil supply channel 2, enabling independent or simultaneous oil supply to the motor control valve 5 and the cylinder control valve 7. The motor control valve 5 can be used to control the start / stop and operating direction of the working motor 6, while the cylinder control valve 7 can be used to control the extension or retention of the working cylinder 8, achieving independent control of the working motor 6 and the working cylinder 8.

[0048] Furthermore, it also includes an unloading valve 9 , the inlet of the unloading valve 9 is connected to the oil supply channel 2 , and the outlet of the unloading valve 9 is connected to the oil return channel 3 .

[0049] like Figure 7 As shown: when the motor and cylinder are moving, if the sudden change of external load causes a sharp fluctuation in pressure, the unloading valve 9 can be opened at this time, and the pressure oil will be directly returned to the return oil channel 3 through the unloading valve 9, so as to achieve the purpose of limiting the pressure and protect the hydraulic system.

[0050] Furthermore, one end of the valve core of the unloading valve 9 is connected to its own inlet oil circuit, and the direction of the oil pressure from its own inlet oil circuit on the valve core of the unloading valve 9 is opposite to the direction of the reset elastic force of the valve core; the unloading valve 9 is a normally closed valve.

[0051] Note: The normally closed valve is a conventional product. A return spring is installed at the other end of the valve core to provide the valve core's return force. When the oil pressure at one end of the normally closed valve core exceeds the return spring's force, the oil pressure pushes the normally closed valve open. When the oil pressure is less than the return spring's force, the return spring pushes the valve core closed.

[0052] When the pressure of the oil supply channel 2 fluctuates violently, the oil pressure can be used to automatically push the unloading valve 9 to open, thereby achieving the purpose of limiting the pressure with good sensitivity.

[0053] Furthermore, it also includes a pilot oil circuit and a pilot safety valve 10, one end of the pilot oil circuit is connected to the oil supply channel 2, the other end of the pilot oil circuit is connected to the inlet end of the pilot safety valve 10 through a first branch, the outlet end of the pilot safety valve 10 is connected to the return oil channel 3, and one end of the valve core of the pilot safety valve 10 is connected to its own inlet oil circuit; the other end of the pilot oil circuit is connected to the other end of the valve core of the unloading valve 9 through a second branch; a first throttling element 11 is provided on the pilot oil circuit.

[0054] Note: The first throttling element 11 can be a throttling hole. During normal operation, the pilot safety valve 10 is closed, and the pressure of the pilot oil circuit and the pressure at both ends of the valve core of the unloading valve 9 are basically equal to the pressure of the oil supply channel 2. The valve core of the unloading valve 9 remains stationary; the unloading valve 9 remains in its initial closed state. When a sudden change in external load causes a violent fluctuation in pressure, the pressure in the oil supply channel 2 increases sharply, and pushes the valve core of the pilot safety valve 10 to move, and the pilot safety valve 10 opens. When the pilot safety valve 10 is opened, under the pressure-reducing effect of the first throttling element 11, there is a pressure difference at both ends of the valve core of the unloading valve 9 in the opposite direction of its own reset spring force; this pressure difference overcomes the valve core reset spring force of the unloading valve 9, pushing the valve core to move until the unloading valve 9 opens, and the pressure oil returns directly to the oil return channel 3 through the unloading valve 9. When the pressure in the oil supply channel 2 is restored, the pressure in the oil supply channel 2 is insufficient to continue to overcome the valve core reset spring force of the pilot safety valve 10, and the pilot safety valve 10 returns to the closed normal state. The pressure difference at both ends of the valve core of the unloading valve 9 disappears, and the valve core of the unloading valve 9 is reset under its own reset spring force, and the unloading valve 9 returns to the closed normal state.

[0055] When overpressure occurs, the pilot safety valve 10 can automatically control the unloading valve 9 to open, thereby achieving the effect of limiting pressure and improving safety; when pressure is restored, the pilot safety valve 10 and the unloading valve 9 can automatically reset, ensuring the stable operation of the hydraulic system and good reliability; during normal operation, the oil pressures at both ends of the valve core of the unloading valve 9 are balanced with each other, are not affected by the pressure of the oil supply channel 2, can adapt to any working pressure, and have good adaptability.

[0056] Furthermore, the valve block 1 is also provided with a first pressure measuring oil circuit 14, a second pressure measuring oil circuit 15 and a third pressure measuring oil circuit 16. The first pressure measuring oil circuit 14 is connected to the oil supply channel 2, the second pressure measuring oil circuit 15 is connected to the second branch, and the third pressure measuring oil circuit 16 is connected to the oil circuit of the working B port of the motor control valve 5.

[0057] By connecting the pressure measuring element through the first pressure measuring oil circuit 14 and the second pressure measuring oil circuit 15, it is convenient to monitor the oil pressure at both ends of the valve core of the unloading valve 9, thereby judging the working status of the unloading valve 9 and the pilot safety valve 10 and detecting faults; by connecting the pressure measuring element through the third pressure measuring oil circuit 16, it is convenient to monitor the working B port pressure of the motor control valve 5, thereby judging the working status of the motor control valve 5 and detecting faults; thereby improving the controllability of the hydraulic system.

[0058] Furthermore, it also includes a cylinder safety valve 12 , the inlet of the cylinder safety valve 12 is connected to the oil circuit of the second outlet of the switching valve 4 , and the outlet of the cylinder safety valve 12 is connected to the oil return channel 3 .

[0059] When only the pressure of the working cylinder 8 fluctuates violently, the pressure from the second outlet of the switching valve 4 to the cylinder control valve 7 is limited by the cylinder safety valve 12, thereby improving the stability and safety of the working cylinder 8 and avoiding the impact on the working motor 6.

[0060] Furthermore, the switching valve 4 is provided with a first inlet and a second inlet, the oil supply channel 2 is connected to the first inlet and the second inlet of the switching valve 4 through a branch, and a second throttling element 13 is provided on the oil circuit of the second inlet; the first outlet of the switching valve 4 corresponds to the first inlet, and the second outlet of the switching valve 4 corresponds to the second inlet.

[0061] Note: In the initial state and when the motor is operating, the first outlet of the switching valve 4 is connected to the first inlet, while the second outlet is closed to the second inlet. In the cylinder operating state, the first outlet of the switching valve 4 is closed to the first inlet, while the second outlet is connected to the second inlet. In the combined motor and cylinder operating state, the first outlet of the switching valve 4 is connected to the first inlet, while the second outlet is connected to the second inlet. The second throttling element 13 can be a throttle orifice.

[0062] It is convenient to make the first outlet and the second outlet of the switching valve 4 have independent passages, and the reliability is good; under the action of the second throttling element 13, it is convenient to limit the oil supply speed of the working cylinder 8, avoiding the working cylinder 8 from moving too fast and causing collision when the oil pressure is large, thereby improving stability.

[0063] Furthermore, one end of the valve core of the switching valve 4 is connected to the oil circuit of its first inlet, and the other end of the valve core of the switching valve 4 is connected to the oil circuit of its second inlet.

[0064] Under the action of the second throttling element 13, when oil is discharged from the second outlet of the switching valve 4, there is a pressure difference at both ends of the valve core of the switching valve 4, and the pressure difference is proportional to the flow rate of the second outlet; when the cylinder is in working state, if the working cylinder 8 moves too fast, the pressure difference at both ends of the valve core of the switching valve 4 increases, and pushes the valve core of the switching valve 4 to move to the first outlet to discharge oil, so as to facilitate the return of part of the pressure oil to the return oil channel 3, avoid the working cylinder 8 from moving too fast and causing collision, and improve the safety of the working cylinder 8.

[0065] Furthermore, the valve core of the motor control valve 5 is provided with an oil return position and a motor position. When the oil return position is working, the pressure oil port, working port A and working port B of the motor control valve 5 are all connected to their own oil return port; when the motor position is working, one of the working port A and working port B of the motor control valve 5 is connected to its own pressure oil port, and the other is connected to its own oil return port; the normal state of the motor control valve 5 is that it works at the oil return position.

[0066] Note: In addition to the embodiment shown in the drawings, two opposite motor positions can also be set.

[0067] When the working motor 6 is not working, it is convenient to relieve the pressure of the hydraulic oil circuit where the working motor 6 is located, and at the same time, the oil from the first outlet of the switching valve 4 directly flows back to the return oil channel 3, avoiding affecting the working motor 6 and improving safety.

[0068] Furthermore, the cylinder control valve 7 is provided with multiple ones, the pressure oil port of the first cylinder control valve 7 is connected to the second outlet of the switching valve 4, the pressure oil ports of the remaining cylinder control valves 7 are connected to the return oil ports of their previous cylinder control valves 7, and the return oil port of the last cylinder control valve 7 is connected to the return oil channel 3.

[0069] During installation, each cylinder control valve 7 can be connected to at least one working cylinder 8 , wherein the working port A and the working port B of the cylinder control valve 7 are respectively connected to the two ends of the corresponding working cylinder 8 .

[0070] It is convenient to provide interfaces for multiple working cylinders 8, which can drive multiple working cylinders 8 to extend and retract synchronously, thereby improving the load capacity; at the same time, when the cylinder load required by the machine is small, the rear half of the cylinder control valve 7 can be switched to the oil return state, and the pressure oil port of the rear half of the cylinder control valve 7 is connected to its own oil return port, thereby allowing part of the working cylinder 8 to move, which has good flexibility.

[0071] In the description of the present invention, it should be understood that if there are descriptive terms indicating orientation, direction or positional relationship, such as: "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated in this specification is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of understanding the present invention and simplifying the description, and does not indicate or imply that the referred part, element or whole must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0072] In addition, if there are order description terms, such as "first", "second", etc., their use in this specification is to facilitate understanding or simplify the description. For example, in order to distinguish multiple technical features with the same type or function, but they have to be mentioned separately, this specification may use prefix or suffix order description terms to distinguish them. Therefore, it cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of such features. In the description of this utility model, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0073] In the present invention, if terms describing the relative functional relationship of structures are used, such as "install", "connect", "connect", "fix", etc., they should be understood in a broad sense unless otherwise clearly specified and limited. For example, "install", "connect", "connect", etc. can be fixed connections, detachable connections, or integrated; can be mechanical connections or electrical connections; can be direct connections or indirect connections through an intermediate medium, can be internal connections between two elements or interactive relationships between two elements; "fix" can be fixed to form an integral body, or can be detachably fixed through fasteners; can be directly fixed or fixed through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above-mentioned descriptive terms in the present invention can be understood according to the specific circumstances, the context, the coherence of the preceding and following texts, etc.

[0074] In this utility model, if descriptive terms with ancillary or connecting meaning appear, for example, a first feature being "on" or "below" a second feature, these should not be interpreted as limiting unless otherwise expressly specified or limited. For example, "on" or "below" may refer to direct contact between the first and second features, or indirect contact between the first and second features through an intermediary. Those skilled in the art will understand the specific meanings of these descriptive terms in this utility model based on the specific circumstances, context, and coherence of the preceding and following texts.

[0075] Furthermore, when a first feature is “above,” “above,” or “above” a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. When a first feature is “below,” “below,” or “below” a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0076] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" 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 invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments, examples and features of different embodiments and examples described in this specification, unless there is any contradiction, and these combinations or combinations should all fall within the scope summarized by the present invention.

[0077] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are illustrative and cannot be understood as limiting the present invention. Changes, modifications, substitutions and variations of the above embodiments made by ordinary technicians in the field within the scope of information available from public channels and in combination with the technical inspiration given by the application documents are still within the scope of protection of the present application.

Claims

1. A solenoid valve assembly for a tractor, characterized by: The invention comprises a valve block (1), wherein the valve block (1) is provided with an oil supply channel (2), an oil return channel (3), a switching valve (4), a motor control valve (5) and a cylinder control valve (7); the oil supply channel (2) is connected to the switching valve (4); the first outlet of the switching valve (4) is connected to the pressure oil port of the motor control valve (5); the oil return port of the motor control valve (5) is connected to the oil return channel (3); the second outlet of the switching valve (4) is connected to the pressure oil port of the cylinder control valve (7); the oil return port of the cylinder control valve (7) is connected to the oil return channel (3).

2. The solenoid valve assembly for a tractor according to claim 1, characterized in that: The unloading valve (9) is also included. The inlet of the unloading valve (9) is connected to the oil supply channel (2), and the outlet of the unloading valve (9) is connected to the oil return channel (3).

3. The solenoid valve assembly for a tractor according to claim 2, characterized in that: One end of the valve core of the unloading valve (9) is connected to its own inlet oil circuit. The direction of the oil pressure from its own inlet oil circuit to which the valve core of the unloading valve (9) is subjected is opposite to the direction of the resetting elastic force of the valve core. The unloading valve (9) is a normally closed valve.

4. The solenoid valve assembly for a tractor according to claim 3, characterized in that: The invention also includes a pilot oil circuit and a pilot safety valve (10), wherein one end of the pilot oil circuit is connected to the oil supply channel (2), the other end of the pilot oil circuit is connected to the inlet end of the pilot safety valve (10) through a first branch, the outlet end of the pilot safety valve (10) is connected to the oil return channel (3), one end of the valve core of the pilot safety valve (10) is connected to its own inlet oil circuit; the other end of the pilot oil circuit is connected to the other end of the valve core of the unloading valve (9) through a second branch; and a first throttling element (11) is provided on the pilot oil circuit.

5. The solenoid valve assembly for a tractor according to claim 4, characterized in that: The valve block (1) is further provided with a first pressure measuring oil circuit (14), a second pressure measuring oil circuit (15) and a third pressure measuring oil circuit (16). The first pressure measuring oil circuit (14) is connected to the oil supply channel (2), the second pressure measuring oil circuit (15) is connected to the second branch circuit, and the third pressure measuring oil circuit (16) is connected to the oil circuit of the working port B of the motor control valve (5).

6. The solenoid valve assembly for a tractor according to claim 1, characterized in that: It also includes an oil cylinder safety valve (12), the inlet of the oil cylinder safety valve (12) is connected to the oil circuit of the second outlet of the switching valve (4), and the outlet of the oil cylinder safety valve (12) is connected to the oil return channel (3).

7. The solenoid valve assembly for a tractor according to claim 1, characterized in that: The switching valve (4) is provided with a first inlet and a second inlet, the oil supply passage (2) is connected to the first inlet and the second inlet of the switching valve (4) through a branch, and a second throttling element (13) is provided on the oil path of the second inlet; the first outlet of the switching valve (4) corresponds to the first inlet, and the second outlet of the switching valve (4) corresponds to the second inlet.

8. The solenoid valve assembly for a tractor according to claim 7, characterized in that: One end of the valve core of the switching valve (4) is connected to the oil circuit of its first inlet, and the other end of the valve core of the switching valve (4) is connected to the oil circuit of its second inlet.

9. The solenoid valve assembly for a tractor according to claim 1, characterized in that: The valve core of the motor control valve (5) is provided with an oil return position and a motor position. When the oil return position is in operation, the pressure oil port, the working port A and the working port B of the motor control valve (5) are all connected to the own oil return port. When the motor position is in operation, one of the working port A and the working port B of the motor control valve (5) is connected to the own pressure oil port, and the other is connected to the own oil return port. The normal state of the motor control valve (5) is that it is in operation at the oil return position.

10. The solenoid valve assembly for a tractor according to claim 1, characterized in that: The oil cylinder control valve (7) is provided with a plurality of oil cylinder control valves (7), the pressure oil port of the first oil cylinder control valve (7) is connected to the second outlet of the switching valve (4), the pressure oil ports of the remaining oil cylinder control valves (7) are connected to the oil return ports of the previous oil cylinder control valve (7), and the oil return port of the last oil cylinder control valve (7) is connected to the oil return channel (3).

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