Electromagnetic valve group for tractor

Abstract

The electromagnetic valve set for the tractor comprises a valve block, the valve block is provided with an oil supply channel, an oil return channel, a switching valve, a motor control valve and an oil cylinder control valve, 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 practicability is high. And popularization and application of diversified tools of the tractor are facilitated.

Description

Technical Field

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

[0002] Through the combination with different machines and implements, the application scope of tractors is constantly expanding, making the market space for tractors as main machines wider. With the emergence and use of more and more diversified machines and implements such as weeding, pruning, spraying, rotary tillage, and traction, higher requirements are also put forward for tractors as main machines. As auxiliary working devices of the tractor main body, the machine implement has different forms such as cylinder control and motor control, and its functions are becoming more and more abundant.

[0003] At present, when a tractor needs to work in combination with different types of implements, in order to provide power to the implements, the corresponding type of drive equipment needs to be switched on the tractor accordingly. Different drive equipment has different hydraulic oil supply methods. For example, the oil cylinder supplies oil for a round trip, and the total amount of a single trip is limited; the motor supplies oil for a single trip continuously. Therefore, when switching the drive equipment, it often also means replacing the supporting hydraulic system, which is not only cumbersome to operate, but also has high professional requirements for the replacement personnel, which limits the promotion and application of diversified implements of tractors. Summary of the invention

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

[0005] The technical solution of the present invention to solve the above technical problems is as follows: The present invention 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, wherein 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.

[0006] The beneficial effects of the present invention are: By adopting the present invention, when the tractor switches the tool combination operation, according to the cylinder drive, motor drive or compound drive required by the tool, 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 working state of the switching valve, without replacing the supporting hydraulic system. The operation is convenient, and ordinary users can also complete the operation efficiently. The use cost is low, which is convenient for the promotion and application of tractor diversified tools. Specifically, the switching valve controls the flow direction of the pressure oil in the oil supply channel, and the motor control valve and the cylinder control valve can be supplied with oil independently or simultaneously; the motor control valve can be used to control the start and stop and the running direction of the working motor, and the cylinder control valve can be used to control the extension or retention of the working cylinder, thereby realizing independent control of the working motor and the working cylinder.

[0007] Based on the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, it also includes a relief valve, the inlet of the relief valve is connected to the oil supply channel, and the outlet of the relief valve is connected to the oil return channel.

[0009] When the motor and cylinder are moving, if the sudden change of external load causes a drastic fluctuation in pressure, the unloading valve can be opened at this time, and the pressure oil will return directly to the oil return channel through the unloading valve, thereby achieving the purpose of limiting the pressure and protecting the hydraulic system.

[0010] 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 that the valve core of the unloading valve receives is opposite to the direction of the resetting elastic force of the valve core; the unloading valve is a normally closed valve.

[0011] 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.

[0012] 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, 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; a first throttling element is provided on the pilot oil circuit.

[0013] When overpressure occurs, the pilot safety valve can automatically control the unloading valve to open, thereby achieving the effect of limiting pressure and improving safety. When pressure is restored, the pilot safety valve and the unloading valve can automatically reset, ensuring stable operation of the hydraulic system with 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.

[0014] 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 road, and the third pressure measuring oil circuit is connected to the oil circuit of the working B port of the motor control valve.

[0015] 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, so as to judge the working state of the unloading valve and the pilot safety valve and detect 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, so as to judge the working state of the motor control valve and detect faults; the controllability of the hydraulic system is improved.

[0016] 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.

[0017] When only the pressure of the working cylinder fluctuates violently, the pressure from the second outlet of the switching valve to the cylinder control valve is limited by the cylinder safety valve, thereby improving the stability and safety of the working cylinder and avoiding the impact on the working motor.

[0018] 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.

[0019] It is convenient to make the first outlet and the second outlet of the switching valve have independent passages, and the reliability is good; 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 moving too fast and causing collision when the oil pressure is large, and improve stability.

[0020] 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.

[0021] Under the action of the second throttling element, when oil flows out of 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 the valve core of the switching valve is pushed 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, avoid the collision caused by the working cylinder moving too fast, and improve the safety of the working cylinder.

[0022] Furthermore, an oil return position and a motor position are provided on the valve core of the motor control valve. 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 its 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 at the oil return position.

[0023] 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 directly flows back to the oil return channel to avoid affecting the working motor, which is safe.

[0024] 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 oil return ports of the previous cylinder control valves, and the oil return port of the last cylinder control valve is connected to the oil return channel.

[0025] 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 cylinder control valve in the rear part can be switched to the oil return state, and the pressure oil port of the cylinder control valve in the rear part is connected to its own oil return port, thereby allowing part of the working cylinders to move, with good flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0027] Figure 2 for Figure 1 Schematic diagram of the three-dimensional structure from the left view direction.

[0028] Figure 3 It is a schematic diagram of the initial state of the present invention.

[0029] Figure 4 It is a schematic diagram of the working state of the motor of the present invention.

[0030] Figure 5 It is a schematic diagram of the working state of the oil cylinder of the present invention.

[0031] Figure 6 It is a schematic diagram of the combined working state of the motor and the oil cylinder of the present invention.

[0032] Figure 7 It is a schematic diagram of the safe unloading state of the present invention.

[0033] In the accompanying drawings, the technical features represented by the reference numerals are as follows: 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

[0034] 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.

[0035] The present invention refers to Figure 1-7 .

[0036] The present invention 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.

[0037] principle: 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 oil return 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 oil return 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, the cylinder is extended when the cylinder body end is filled with oil, and the cylinder is shortened when the piston rod end is filled with oil.

[0038] Note: Switching valve 4, motor control valve 5, and cylinder control valve 7 are all reversing valves. The general naming method of the reversing valve interface is port A (working port A), port B (working port B), port P, and port T. Generally, port A and port B are working oil ports, which are used to connect the hydraulic components controlled by themselves; port P is a pressure oil port for the entry of pressure oil; port T is a return oil port for oil return. The reversing valve makes the specific position of the valve core work through the movement of its own valve core, so that a specific connection relationship is generated between port A, port B, port P, and port T through a specific position, thereby changing the working state of the reversing valve.

[0039] After being installed in the hydraulic system, it has the following status, such as Figure 3-7 As shown (the direction of the arrow is the direction of oil flow): In the initial state, Figure 3 As shown: the switching valve 4 is in the first outlet oil discharge state, and the pressure oil port, working port A and working port B of the motor control valve 5 are all connected to the return oil port. After the pressure oil enters the switching valve 4, the flow path is: the first outlet of the switching valve 4 → the pressure oil port of the motor control valve 5 → the return oil port of the motor control valve 5 → the return oil channel 3.

[0040] When the motor is working, Figure 4 As shown: the switching valve 4 is in the first outlet oil discharge state, one of the working A port and the working B port of the motor control valve 5 is connected to its own pressure oil port, and the other is connected to its own return oil port. After the pressure oil enters the switching valve 4, the flow path is: the first outlet of the switching valve 4 → the pressure oil port of the motor control valve 5 → the working B / A port of the motor control valve 5 → the working motor 6 → the working A / B port of the motor control valve 5 → the return oil port of the motor control valve 5 → the return oil channel 3.

[0041] When the cylinder is in working condition, Figure 5 As shown: the switching valve 4 is in the state of oil discharge from the second outlet, one of the working A port and the working B port of the cylinder control valve 7 is connected to its own pressure oil port, and the other is connected to its own return oil port. After the pressure oil enters the switching valve 4, the flow path is: the second outlet of the switching valve 4 → the pressure oil port of the cylinder control valve 7 → the working B / A port of the cylinder control valve 7 → the working cylinder 8 → the working A / B port of the cylinder control valve 7 → the return oil port of the cylinder control valve 7 → the return oil channel 3.

[0042] When the motor and cylinder are in combined 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.

[0043] By adopting the present invention, when the tractor switches the tool combination operation, according to the cylinder drive, motor drive or compound drive required by the tool, it is only necessary to connect the required working motor 6 through the motor control valve 5, connect the required working cylinder 8 through the cylinder control valve 7, and change the working state of the switching valve 4, without replacing the supporting hydraulic system. The operation is convenient, and ordinary users can also complete the operation efficiently. The use cost is low, which is convenient for the promotion and application of tractor diversified tools. Specifically, the switching valve 4 controls the flow direction of the pressure oil in the oil supply channel 2, and the motor control valve 5 and the cylinder control valve 7 can be supplied with oil independently or simultaneously; the motor control valve 5 can be used to control the start and stop and the running direction of the working motor 6, and the cylinder control valve 7 can be used to control the extension or maintenance of the working cylinder 8, so as to realize the independent control of the working motor 6 and the working cylinder 8.

[0044] Furthermore, it also includes a relief valve 9 , the inlet of the relief valve 9 is connected to the oil supply channel 2 , and the outlet of the relief valve 9 is connected to the oil return channel 3 .

[0045] like Figure 7 As shown: when the motor and cylinder are moving, if the sudden change of external load causes a drastic fluctuation in pressure, the unloading valve 9 can be opened at this time, and the pressure oil can 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.

[0046] 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 that the valve core of the unloading valve 9 is subjected to is opposite to the direction of the resetting elastic force of the valve core; the unloading valve 9 is a normally closed valve.

[0047] Note: The normally closed valve is a prior art product, and a return spring is provided at the other end of the valve core to provide the return spring force of the valve core. When the oil pressure at one end of the valve core of the normally closed valve is greater than the return spring force, the oil pressure pushes the normally closed valve to open; when the oil pressure is less than the return spring force, the return spring pushes the valve core to close.

[0048] 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.

[0049] 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, 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.

[0050] Note: The first throttling element 11 can be a throttling hole. During normal operation, the pilot safety valve 10 is closed, 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, and the valve core of the unloading valve 9 remains stationary; the unloading valve 9 remains in the initial closed state. When the sudden change of the external load causes a drastic 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 reduction 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 elastic force; this pressure difference overcomes the valve core reset elastic force of the unloading valve 9, pushes 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, the pilot safety valve 10 returns to the closed state, the pressure difference at both ends of the valve core of the unloading valve 9 disappears, the valve core of the unloading valve 9 resets under its own reset spring force, and the unloading valve 9 returns to the closed state.

[0051] 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 with 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, and can adapt to any working pressure with good adaptability.

[0052] 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.

[0053] 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, so as to judge the working status of the unloading valve 9 and the pilot safety valve 10 and detect 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, so as to judge the working status of the motor control valve 5 and detect faults; the controllability of the hydraulic system is improved.

[0054] 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 .

[0055] 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 influence on the working motor 6.

[0056] Furthermore, the switching valve 4 is provided with a first inlet and a second inlet, the oil supply channel 2 connects 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.

[0057] Note: In the initial state and the motor working state, the first outlet of the switching valve 4 is connected to the first inlet, and the second outlet is closed to the second inlet. In the oil cylinder working state, the first outlet of the switching valve 4 is closed to the first inlet, and the second outlet is connected to the second inlet. In the motor and oil cylinder combined working state, the first outlet of the switching valve 4 is connected to the first inlet, and the second outlet is connected to the second inlet. The second throttling element 13 can be a throttling hole.

[0058] 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, to avoid the working cylinder 8 from moving too fast and causing collision when the oil pressure is high, and to improve stability.

[0059] 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.

[0060] Under the action of the second throttling element 13, when oil flows out of 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 the valve core of the switching valve 4 is pushed 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 collision caused by the working cylinder 8 moving too fast, and improve the safety of the working cylinder 8.

[0061] Furthermore, an oil return position and a motor position are provided on the valve core of the motor control valve 5. 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.

[0062] Note: In addition to the embodiment shown in the drawings, two opposite motor positions can also be set.

[0063] 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.

[0064] 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 the previous cylinder control valve 7, and the return oil port of the last cylinder control valve 7 is connected to the return oil channel 3.

[0065] During installation, each cylinder control valve 7 can be connected to at least one working cylinder 8 , wherein the working A port and the working B port of the cylinder control valve 7 are respectively connected to the two ends of the corresponding working cylinder 8 .

[0066] 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 cylinders 8 to move, with good flexibility.

[0067] 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.

[0068] In addition, if there are order description terms, such as "first", "second", etc., their purpose in this specification is to facilitate understanding or simplify description. For example, in order to distinguish multiple technical features of 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" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0069] In the present invention, if the 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 a fixed connection, a detachable connection, or an integrated one; can be a mechanical connection or an electrical connection; can be a direct connection or an indirect connection through an intermediate medium, can be the internal connection of two elements or the interaction relationship between two elements; "fix" can be an integrated fixation or a detachable fixation through fasteners; can be a direct fixation or a fixation 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 context, etc.

[0070] In the present invention, if there are descriptive terms with subsidiary or connecting meanings, for example, a first feature is "on" or "below" a second feature, unless otherwise clearly specified and limited, it should not be interpreted in a restrictive manner. For example, "on" or "below" can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above descriptive terms in the present invention can be understood according to the specific circumstances, the context, the coherence of the context, etc.

[0071] Furthermore, the first feature being “above”, “above”, and “above” the second feature 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. The first feature being “below”, “below”, and “below” the second feature 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.

[0072] 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 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 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, examples and features of the different embodiments and examples described in this specification without contradiction, and these combinations or combinations shall all fall within the scope summarized by the present invention.

[0073] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments made by a person skilled in the art within the scope of information available from public channels and in combination with the technical inspiration provided by the present application documents are still within the scope of protection of the present application.

Claims

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

3. The solenoid valve assembly for 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 that the valve core of the unloading valve (9) is subjected to 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: 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 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 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 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 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).

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 works 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, 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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