Lift control valve group, lift system and tractor

Abstract

The utility model provides a kind of lift control valve group, lift system and tractor.A kind of lift control valve group, comprising: valve body, main valve, logic valve and unloading valve, main valve core is provided in the main valve, logic valve core is provided in the logic valve, unloading valve core is provided in the unloading valve, the main valve core, the logic valve core and the unloading valve core are slidably installed in the valve body, when main valve core is in middle position, the main valve core is communicated with the logic valve and the unloading valve respectively by first hydraulic control combination passage;When main valve core is in right position, the main valve core is communicated with the logic valve and the unloading valve respectively by second hydraulic control combination passage;When main valve core is in left position, the main valve core is communicated with the logic valve and the unloading valve respectively by third hydraulic control combination passage.

Description

Technical Field

[0001] This utility model relates to the field of control valve technology, and in particular to a lifting control valve assembly, a lifting system, and a tractor. Background Technology

[0002] The lift control valve assembly is a crucial component for controlling the lifting function. During field operations, the raising, lowering, and position holding of agricultural implements are all controlled through the lift control valve. By manipulating the valve core displacement, the flow direction of the hydraulic fluid is altered, thereby controlling the lifting of the implement. The performance of the lift valve assembly directly determines the efficiency and effectiveness of the operation, ultimately affecting the yield.

[0003] Ordinary four-position six-way control valves have limited functionality, high pressure loss, poor control accuracy, and significant internal leakage, requiring a dedicated hydraulic lock and increasing costs. Most existing force-lifting valve assemblies employ a mechanical linkage structure between the main valve and the lowering valve. This structure is complex, has a large pressure loss in the neutral position, mechanically opens the check valve, has unreliable sealing, and poor micro-motion control. Utility Model Content

[0004] The technical problem to be solved by this utility model is to address the shortcomings of the existing technology by providing a lifting control valve group, a lifting system, and a tractor.

[0005] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A lifting control valve assembly includes: a valve body, a main valve, a logic valve, and an unloading valve. The main valve is provided with a main valve core, the logic valve is provided with a logic valve core, and the unloading valve is provided with an unloading valve core. The main valve core, the logic valve core, and the unloading valve core are all slidably installed in the valve body. When the main valve core is in the neutral position, the main valve core is connected to the logic valve and the unloading valve respectively through a first hydraulic control combination channel. When the main valve core is in the right position, the main valve core is connected to the logic valve and the unloading valve respectively through a second hydraulic control combination channel. When the main valve core is in the left position, the main valve core is connected to the logic valve and the unloading valve respectively through a third hydraulic control combination channel.

[0006] The beneficial effects of adopting this utility model's technical solution are as follows: Different control requirements are achieved through the mutual cooperation of valve cores such as the main valve, unloading valve, and logic valve. The main valve, through hydraulic control, is linked with the unloading valve and logic valve to achieve different oil circuit connections. Hydraulic control improves control sensitivity, increases flow capacity, and expands the valve's applicability. The descending valve uses a logic valve, which, with hydraulic control, ensures reliable sealing and low leakage. The mid-position unloading uses a main valve hydraulically controlled unloading valve structure, resulting in low pressure loss.

[0007] Furthermore, the valve body is provided with an oil inlet, a first oil outlet, a second oil outlet, a load port, a main valve core cavity for installing the main valve core, a logic valve cavity for installing the logic valve core, a unloading valve cavity for installing the unloading valve core, a first oil passage, a fourth oil passage, a fifth oil passage, a sixth oil passage, a seventh oil passage, a ninth oil passage, and an oil drain port; the main valve core is provided with a second oil passage, a third oil passage, and an eighth oil passage, which are sequentially connected; the main valve core is provided with a throttling orifice, which is connected to the eighth oil passage, and the ninth oil passage is connected to both the oil drain port and the main valve core cavity; the oil inlet and the first oil outlet are both connected to... The main valve core cavity is connected, the second oil outlet is connected to the unloading valve cavity, and the load port is connected to the logic valve cavity; the unloading valve cavity is connected to the main valve core cavity through the first oil passage; the fourth oil passage is connected to the fifth oil passage, the main valve core cavity is connected to the fourth oil passage, the logic valve cavity is connected to the fifth oil passage, and the logic valve cavity is connected to the main valve core cavity through the sixth and seventh oil passages; a logic valve spring is provided in the logic valve cavity, and the logic valve core is slidably installed in the logic valve cavity through the logic valve spring; an unloading valve spring is provided in the unloading valve cavity, and the unloading valve core is slidably installed in the unloading valve cavity through the unloading valve spring.

[0008] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The structural design facilitates the achievement of different control requirements through the mutual cooperation of valve cores such as the main valve, unloading valve, and logic valve. The main valve is linked with the unloading valve and logic valve through hydraulic control to achieve different oil circuit connections. Hydraulic control can improve control sensitivity, increase flow capacity, and expand the applicability of the valve. The descending valve adopts a logic valve, which is hydraulically controlled, ensuring reliable sealing and low leakage. The mid-position unloading adopts a main valve hydraulically controlled unloading valve structure, resulting in low pressure loss. The main valve core is equipped with control oil passages and throttling orifices, controlling the unloading valve and logic valve through hydraulic control, resulting in a simple control method and high control accuracy. A throttling groove is opened at the valve port of the main valve core to improve the micro-motion performance and control accuracy of the main valve.

[0009] Furthermore, when the main valve core is in the neutral position, the first hydraulic control combination channel includes: a channel in the unloading valve chamber that connects the side with the unloading valve spring, the first oil passage, and the first oil outlet in sequence; a channel that connects the oil inlet and the second oil outlet in sequence; and a channel in the logic valve chamber that connects the side with the logic valve spring, the sixth oil passage, the seventh oil passage, and the load port in sequence.

[0010] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the main valve core is in the neutral position, the hydraulic oil in the control spring chamber of the unloading valve core is connected to the first outlet through the first oil passage and the main valve core. The side of the unloading valve chamber with the unloading valve spring is pressureless. The pressure oil from the inlet acts on the right end of the unloading valve core. Since the unloading valve core spring chamber is connected to the first outlet for unloading, the pressure overcomes the unloading valve spring to open the first valve port for unloading. The stiffness of the unloading valve spring is very small, and it is only necessary to realize the reset function of the valve core. Therefore, the unloading pressure in the neutral position is very small, and the power loss is small. Also, since most of the pressure oil does not pass through the main valve core during unloading in the neutral position, it returns directly to the oil tank through the unloading valve, and the pressure loss along the way is small. At this time, the right spring chamber of the logic valve is connected to the load port through the oil passage, the fourth valve port, and the seventh oil passage. The pressure in the spring chamber is equal to the load pressure. Under the combined action of the spring force and the load pressure, the logic valve reliably closes the third valve port, so that the machine is kept in the set position. At this time, the machine is in a neutral and stationary state.

[0011] Furthermore, when the main valve core is in the right position, the second hydraulic control combination channel includes: a channel in the unloading valve chamber that sequentially connects the side with the unloading valve spring, the first oil passage, the second oil passage, the third oil passage, and the oil inlet; a channel sequentially connects the oil inlet, the fourth oil passage, the fifth oil passage, and the side of the logic valve chamber without the logic valve spring; a channel in the logic valve chamber that sequentially connects the side with the logic valve spring, the sixth oil passage, the seventh oil passage, and the load port; and a channel sequentially connects the oil inlet, the fourth oil passage, the fifth oil passage, and the load port.

[0012] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the valve core moves to the right and is in the lifting position, the hydraulic oil in the control spring chamber of the unloading valve core is connected to the inlet pressure oil through the first oil passage, the second oil passage, and the third oil passage, guiding the pressure oil to the spring chamber of the unloading valve core. At this time, the left side of the unloading valve core is greater than the hydraulic pressure on the right side under the combined action of spring force and hydraulic pressure, reliably closing the first valve port of the inlet and the second outlet. The inlet pressure oil passes through the opened second valve port, through the fourth and fifth oil passages, and reaches the left side of the logic valve. At this time, the right spring chamber of the logic valve is connected to the load port through the sixth oil passage, the fourth valve port, and the seventh oil passage. The load port is also connected to the lower chamber of the lifting cylinder. The load port pressure is the cylinder load pressure. When the pressure on the left side of the logic valve, i.e., the inlet pressure, is greater than the load port load pressure, the third valve port of the logic valve can be opened, connecting the inlet port to the load port through the second valve port, the fourth oil passage, the fifth oil passage, and the third valve port. The pressure oil enters the lifting cylinder, pushing the cylinder to move and realizing the lifting function.

[0013] Furthermore, when the main valve core is in the left position, the third hydraulic control combination channel includes: a channel in the unloading valve chamber that connects the unloading valve spring on one side, the first oil passage, and the first oil outlet in sequence; a channel that connects the oil inlet and the second oil outlet in sequence; a channel in the logic valve chamber that connects the logic valve spring on one side, the sixth oil passage, the throttle orifice, the eighth oil passage, the ninth oil passage, and the drain port in sequence; and a channel that connects the load port, the fifth oil passage, the fourth oil passage, and the first oil outlet in sequence.

[0014] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the main valve core is moved to the left, it is in the descending position. The hydraulic oil in the control spring chamber of the unloading valve core is connected to the first oil outlet through the first oil passage and the fifth valve port formed by the main valve core and the valve body. The pressure in the spring chamber is unloaded. Under the action of the pressure oil on the right side, the unloading valve core moves to the left, opening the first valve port. The oil inlet is connected to the second oil outlet, and the pressure oil is unloaded at low pressure. At the same time, the leftward movement of the main valve core reliably closes the second valve port and opens the seventh valve port. At this time, the right spring chamber of the logic valve is connected to the drain port through the sixth oil passage, the fixed throttle hole on the main valve core, the eighth oil passage, and the ninth oil passage, and returns directly to the oil tank. With no pressure in the spring chamber, the logic valve core moves to the right under the load pressure of the load port, opening the third valve port. The load port is connected to the first oil outlet through the third valve port, the fifth oil passage, the fourth oil passage, and the seventh valve port. The pressure oil of the lifting cylinder returns to the oil tank through this path via the first oil outlet, and the machine descends. The main valve core is equipped with control oil passages and throttling orifices, controlling the unloading valve and logic valve via hydraulic control. This method is simple and offers high control precision. A throttling groove is located at the valve port of the main valve core to improve the micro-motion performance and control accuracy of the main valve.

[0015] Furthermore, the first oil outlet, the second oil outlet, and the drain port are all connected to an oil tank; the load port is connected to the lower chamber of the lifting cylinder.

[0016] The beneficial effects of adopting the above-mentioned further technical solution are: it facilitates the collection of oil from the oil outlet and drain port by the oil tank; the load port is connected to the lower chamber of the lifting cylinder, facilitating the entry of pressurized oil into the lifting cylinder to drive its movement and achieve the lifting function; and it facilitates the return of pressurized oil from the lifting cylinder to the oil tank through the first oil outlet, thereby enabling the machine to descend.

[0017] Furthermore, the unloading valve core is provided with a first protrusion, which forms a first valve port with the valve body, and the second oil outlet is connected to the oil inlet through the first valve port; the main valve core is provided with a second protrusion, a third protrusion, and a fourth protrusion, the third protrusion being located between the second protrusion and the fourth protrusion, the second protrusion forming a fifth valve port and a seventh valve port with the valve body, the first oil outlet being connected to the fifth valve port and the seventh valve port respectively, the first oil passage being connected to the fifth valve port, the fourth oil passage being connected to the seventh valve port, the third protrusion forming a second valve port with the valve body, the oil inlet and the fourth oil passage being connected to the second valve port, the fourth protrusion forming a fourth valve port with the valve body, and the sixth oil passage being connected to the fourth valve port; the logic valve forming a third valve port with the valve body, and the fifth oil passage being connected to the third valve port.

[0018] The beneficial effects of adopting the above-mentioned further technical solutions are: the protrusion and valve port settings facilitate the opening and closing of the oil passage, and facilitate the realization of different control requirements through the mutual cooperation of valve cores such as the main valve, unloading valve and logic valve. The main valve is linked with the unloading valve, logic valve and other valves through hydraulic control to realize the connection of different oil circuits. The hydraulic control can improve control sensitivity, increase flow capacity and expand the applicability of the valve.

[0019] Furthermore, the first protrusion, the second protrusion, the third protrusion, and the fourth protrusion are all cylinders to achieve the valve port sealing function; the main valve core is located between the logic valve core and the unloading valve core.

[0020] The beneficial effects of adopting the above-mentioned further technical solution are: the protrusion is cylindrical, which facilitates the closure of the protrusion and the opening of the corresponding valve port, thereby improving the stability and reliability of the control valve assembly. The main valve core is located between the logic valve core and the unloading valve core, which facilitates the oil passage design of the main valve, logic valve, and unloading valve, improves integration, simplifies the oil passage connection method, and reduces costs.

[0021] In addition, this utility model also provides a lifting system, including the aforementioned lifting control valve assembly.

[0022] In addition, this utility model also provides a tractor, including the aforementioned lifting system.

[0023] The advantages of this invention in its additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is one of the structural schematic diagrams of the lifting control valve assembly provided in an embodiment of this utility model.

[0026] Figure 2 This is the second schematic diagram of the lifting control valve assembly provided in an embodiment of the present utility model.

[0027] Figure 3 The third schematic diagram of the lifting control valve assembly provided in this embodiment of the utility model.

[0028] Figure 4 The fourth schematic diagram of the lifting control valve assembly provided in this embodiment of the utility model.

[0029] Figure 5 The fifth schematic diagram of the lifting control valve assembly provided in the embodiment of this utility model.

[0030] Figure 6 This is the sixth schematic diagram of the lifting control valve assembly provided in the embodiment of this utility model.

[0031] Figure 7 This is a schematic diagram of the lifting control valve assembly provided in an embodiment of the present utility model.

[0032] Reference numerals: 1. Valve body; 2. Main valve core; 3. Logic valve core; 4. Unloading valve core; 5. Oil inlet; 6. First oil outlet; 7. Second oil outlet; 8. Load port; 9. First oil passage; 10. Fourth oil passage; 11. Fifth oil passage; 12. Sixth oil passage; 13. Seventh oil passage; 14. Ninth oil passage; 15. Drain port; 16. Second oil passage; 17. Third oil passage; 18. Eighth oil passage; 19. Throttling orifice; 20. First valve port; 21. Fifth valve port; 22. Seventh valve port; 23. Second valve port; 24. Fourth valve port; 25. Third valve port. Detailed Implementation

[0033] The principles and features of this utility model are described below with reference to the accompanying drawings. The embodiments described are only used to explain this utility model and are not intended to limit the scope of this utility model.

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0036] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0037] In the description of the embodiments of this utility model, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0038] In the description of the embodiments of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0039] like Figures 1 to 7As shown, this utility model embodiment provides a lifting control valve assembly, including: a valve body 1, a main valve, a logic valve, and an unloading valve. The main valve is provided with a main valve core 2, the logic valve is provided with a logic valve core 3, and the unloading valve is provided with an unloading valve core 4. The main valve core 2, the logic valve core 3, and the unloading valve core 4 are all slidably installed in the valve body 1. When the main valve core 2 is in the neutral position, the main valve core 2 is connected to the logic valve and the unloading valve respectively through a first hydraulic control combination channel; when the main valve core 2 is in the right position, the main valve core 2 is connected to the logic valve and the unloading valve respectively through a second hydraulic control combination channel; when the main valve core 2 is in the left position, the main valve core 2 is connected to the logic valve and the unloading valve respectively through a third hydraulic control combination channel.

[0040] The beneficial effects of adopting this utility model's technical solution are as follows: Different control requirements are achieved through the mutual cooperation of valve cores such as the main valve, unloading valve, and logic valve. The main valve, through hydraulic control, is linked with the unloading valve and logic valve to achieve different oil circuit connections. Hydraulic control improves control sensitivity, increases flow capacity, and expands the valve's applicability. The descending valve uses a logic valve, which, with hydraulic control, ensures reliable sealing and low leakage. The mid-position unloading uses a main valve hydraulically controlled unloading valve structure, resulting in low pressure loss.

[0041] The main valve can be operated manually. The lift control valve assembly can be an externally mounted structure (the lift control valve assembly is installed outside the housing).

[0042] This utility model embodiment provides a booster control valve assembly. Different control requirements are achieved through the cooperation of valve cores such as the main valve, unloading valve, and logic valve. The main valve is manually operated for ease of use by the operator. The main valve is linked with the unloading valve and logic valve via hydraulic control, enabling different oil circuit connections. Hydraulic control improves control sensitivity, increases flow capacity, and expands the valve's applicability. 1. The check valve (logic valve) uses hydraulic control, ensuring reliable sealing and low leakage. 2. The mid-position unloading uses a main valve hydraulic control unloading valve structure, resulting in low pressure loss. 3. The main valve core oil passage controls the check valve (logic valve) and unloading valve. 4. External installation of the control valve facilitates maintenance and replacement.

[0043] like Figures 1 to 7As shown, further, the valve body 1 is provided with an oil inlet 5, a first oil outlet 6, a second oil outlet 7, a load port 8, a main valve core cavity for installing the main valve core 2, a logic valve cavity for installing the logic valve core 3, a unloading valve cavity for installing the unloading valve core 4, a first oil passage 9, a fourth oil passage 10, a fifth oil passage 11, a sixth oil passage 12, a seventh oil passage 13, a ninth oil passage 14, and an oil drain port 15; the main valve core 2 is provided with a second oil passage 16, a third oil passage 17, and an eighth oil passage 18, which are sequentially connected; the main valve core 2 is provided with a throttling orifice 19, which is connected to the eighth oil passage 18, and the ninth oil passage 14 is connected to the oil drain port 15 and the main valve core cavity respectively; The oil inlet 5 and the first oil outlet 6 are both connected to the main valve core cavity, the second oil outlet 7 is connected to the unloading valve cavity, and the load port 8 is connected to the logic valve cavity; the unloading valve cavity is connected to the main valve core cavity through the first oil passage 9; the fourth oil passage 10 is connected to the fifth oil passage 11, the main valve core cavity is connected to the fourth oil passage 10, the logic valve cavity is connected to the fifth oil passage 11, and the logic valve cavity is connected to the main valve core cavity through the sixth oil passage 12 and the seventh oil passage 13; a logic valve spring is provided in the logic valve cavity, and the logic valve core 3 is slidably installed in the logic valve cavity through the logic valve spring; an unloading valve spring is provided in the unloading valve cavity, and the unloading valve core 4 is slidably installed in the unloading valve cavity through the unloading valve spring.

[0044] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The structural design facilitates the achievement of different control requirements through the mutual cooperation of valve cores such as the main valve, unloading valve, and logic valve. The main valve is linked with the unloading valve and logic valve through hydraulic control to achieve different oil circuit connections. Hydraulic control can improve control sensitivity, increase flow capacity, and expand the applicability of the valve. The descending valve adopts a logic valve, which is hydraulically controlled, ensuring reliable sealing and low leakage. The mid-position unloading adopts a main valve hydraulically controlled unloading valve structure, resulting in low pressure loss. The main valve core is equipped with control oil passages and throttling orifices, controlling the unloading valve and logic valve through hydraulic control, resulting in a simple control method and high control accuracy. A throttling groove is opened at the valve port of the main valve core to improve the micro-motion performance and control accuracy of the main valve.

[0045] like Figures 1 to 7 As shown, further, when the main valve core 2 is in the neutral position, the first hydraulic control combination channel includes: a channel in the unloading valve chamber that connects the side with the unloading valve spring, the first oil passage 9 and the first oil outlet 6 in sequence; a channel that connects the oil inlet 5 and the second oil outlet 7 in sequence; and a channel in the logic valve chamber that connects the side with the logic valve spring, the sixth oil passage 12, the seventh oil passage 13 and the load port 8 in sequence.

[0046] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the main valve core is in the neutral position, the hydraulic oil in the control spring chamber of the unloading valve core is connected to the first outlet through the first oil passage and the main valve core. The side of the unloading valve chamber with the unloading valve spring is pressureless. The pressure oil from the inlet acts on the right end of the unloading valve core. Since the unloading valve core spring chamber is connected to the first outlet for unloading, the pressure overcomes the unloading valve spring to open the first valve port for unloading. The stiffness of the unloading valve spring is very small, and it is only necessary to realize the reset function of the valve core. Therefore, the unloading pressure in the neutral position is very small, and the power loss is small. Also, since most of the pressure oil does not pass through the main valve core during unloading in the neutral position, it returns directly to the oil tank through the unloading valve, and the pressure loss along the way is small. At this time, the right spring chamber of the logic valve is connected to the load port through the oil passage, the fourth valve port, and the seventh oil passage. The pressure in the spring chamber is equal to the load pressure. Under the combined action of the spring force and the load pressure, the logic valve reliably closes the third valve port, so that the machine is kept in the set position. At this time, the machine is in a neutral and stationary state.

[0047] The first hydraulic control combination channel may include: a first combination channel, a second combination channel, and a third combination channel.

[0048] The first combined channel may include: a channel in which the unloading valve chamber has the unloading valve spring on one side, the first oil passage 9 and the first oil outlet 6 are connected in sequence.

[0049] The second combined channel may include a channel in which the oil inlet 5 and the second oil outlet 7 are connected in sequence.

[0050] The third combined channel may include: a channel in which the logic valve chamber has a logic valve spring on one side, the sixth oil passage 12, the seventh oil passage 13 and the load port 8 are connected in sequence.

[0051] like Figures 1 to 7 As shown, further, when the main valve core 2 is in the right position, the second hydraulic control combination channel includes: a channel in the unloading valve chamber that connects the side with the unloading valve spring, the first oil passage 9, the second oil passage 16, the third oil passage 17, and the oil inlet 5 in sequence; a channel in the logic valve chamber that connects the oil inlet 5, the fourth oil passage 10, the fifth oil passage 11, and the side without the logic valve spring in sequence; a channel in the logic valve chamber that connects the side with the logic valve spring, the sixth oil passage 12, the seventh oil passage 13, and the load port in sequence; and a channel in the logic valve chamber that connects the oil inlet 5, the fourth oil passage 10, the fifth oil passage 11, and the load port 8 in sequence.

[0052] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the valve core moves to the right and is in the lifting position, the hydraulic oil in the control spring chamber of the unloading valve core is connected to the inlet pressure oil through the first oil passage, the second oil passage, and the third oil passage, guiding the pressure oil to the spring chamber of the unloading valve core. At this time, the left side of the unloading valve core is greater than the hydraulic pressure on the right side under the combined action of spring force and hydraulic pressure, reliably closing the first valve port of the inlet and the second outlet. The inlet pressure oil passes through the opened second valve port, through the fourth and fifth oil passages, and reaches the left side of the logic valve. At this time, the right spring chamber of the logic valve is connected to the load port through the sixth oil passage, the fourth valve port, and the seventh oil passage. The load port is also connected to the lower chamber of the lifting cylinder. The load port pressure is the cylinder load pressure. When the pressure on the left side of the logic valve, i.e., the inlet pressure, is greater than the load port load pressure, the third valve port of the logic valve can be opened, connecting the inlet port to the load port through the second valve port, the fourth oil passage, the fifth oil passage, and the third valve port. The pressure oil enters the lifting cylinder, pushing the cylinder to move and realizing the lifting function.

[0053] The second hydraulic control combination channel may include: a fourth combination channel, a fifth combination channel, a sixth combination channel, and a seventh combination channel.

[0054] The fourth combination channel may include: a channel in which the unloading valve chamber has the unloading valve spring on one side, the first oil passage 9, the second oil passage 16, the third oil passage 17 and the oil inlet 5 are connected in sequence.

[0055] The fifth combination channel may include: the oil inlet 5, the fourth oil passage 10, the fifth oil passage 11, and a channel that is sequentially connected to the side of the logic valve chamber that does not have a logic valve spring.

[0056] The sixth combination channel may include: a channel in which the logic valve chamber has a logic valve spring on one side, the sixth oil passage 12, the seventh oil passage 13, and the load port are connected in sequence.

[0057] The seventh combined channel may include a channel in which the oil inlet 5, the fourth oil passage 10, the fifth oil passage 11, and the load port 8 are connected in sequence.

[0058] like Figures 1 to 7 As shown, further, when the main valve core 2 is in the left position, the third hydraulic control combination channel includes: a channel in the unloading valve chamber that connects the side with the unloading valve spring, the first oil passage 9, and the first oil outlet 6 in sequence; a channel that connects the oil inlet 5 and the second oil outlet 7 in sequence; a channel in the logic valve chamber that connects the side with the logic valve spring, the sixth oil passage 12, the throttle orifice 19, the eighth oil passage 18, the ninth oil passage 14, and the drain port 15 in sequence; and a channel that connects the load port 8, the fifth oil passage 11, the fourth oil passage 10, and the first oil outlet 6 in sequence.

[0059] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the main valve core is moved to the left, it is in the descending position. The hydraulic oil in the control spring chamber of the unloading valve core is connected to the first oil outlet through the first oil passage and the fifth valve port formed by the main valve core and the valve body. The pressure in the spring chamber is unloaded. Under the action of the pressure oil on the right side, the unloading valve core moves to the left, opening the first valve port. The oil inlet is connected to the second oil outlet, and the pressure oil is unloaded at low pressure. At the same time, the leftward movement of the main valve core reliably closes the second valve port and opens the seventh valve port. At this time, the right spring chamber of the logic valve is connected to the drain port through the sixth oil passage, the fixed throttle hole on the main valve core, the eighth oil passage, and the ninth oil passage, and returns directly to the oil tank. With no pressure in the spring chamber, the logic valve core moves to the right under the load pressure of the load port, opening the third valve port. The load port is connected to the first oil outlet through the third valve port, the fifth oil passage, the fourth oil passage, and the seventh valve port. The pressure oil of the lifting cylinder returns to the oil tank through this path via the first oil outlet, and the machine descends. The main valve core is equipped with control oil passages and throttling orifices, controlling the unloading valve and logic valve via hydraulic control. This method is simple and offers high control precision. A throttling groove is located at the valve port of the main valve core to improve the micro-motion performance and control accuracy of the main valve.

[0060] The third hydraulic control combination channel may include: the eighth combination channel, the ninth combination channel, the tenth combination channel, and the eleventh combination channel.

[0061] The eighth combination channel may include: a channel in which the unloading valve chamber has the unloading valve spring on one side, the first oil passage 9 and the first oil outlet 6 are connected in sequence.

[0062] The ninth combined channel may include a channel in which the oil inlet 5 and the second oil outlet 7 are connected in sequence.

[0063] The tenth combination channel may include: a channel in which the logic valve chamber has a logic valve spring on one side, the sixth oil passage 12, the throttle orifice 19, the eighth oil passage 18, the ninth oil passage 14, and the drain port 15 are connected in sequence.

[0064] The eleventh combined channel may include a channel in which the load port 8, the fifth oil passage 11, the fourth oil passage 10, and the first oil outlet 6 are connected in sequence.

[0065] like Figures 1 to 7 As shown, the first oil outlet 6, the second oil outlet 7, and the oil drain 15 are all connected to an oil tank; the load port 8 is connected to the lower chamber of the lifting cylinder.

[0066] The beneficial effects of adopting the above-mentioned further technical solution are: it facilitates the collection of oil from the oil outlet and drain port by the oil tank; the load port is connected to the lower chamber of the lifting cylinder, facilitating the entry of pressurized oil into the lifting cylinder to drive its movement and achieve the lifting function; and it facilitates the return of pressurized oil from the lifting cylinder to the oil tank through the first oil outlet, thereby enabling the machine to descend.

[0067] like Figures 1 to 7 As shown, further, the unloading valve core 4 is provided with a first protrusion, which, together with the valve body, forms a first valve port 20. The second oil outlet 7 is connected to the oil inlet 5 through the first valve port 20. The main valve core 2 is provided with a second protrusion, a third protrusion, and a fourth protrusion. The third protrusion is located between the second protrusion and the fourth protrusion. The second protrusion, together with the valve body 1, forms a fifth valve port 21 and a seventh valve port 22. The first oil outlet 6 is connected to the fifth valve port 21 and the seventh valve port 22 respectively. The valve is connected to port 22; the first oil passage 9 is connected to the fifth valve port 21; the fourth oil passage 10 is connected to the seventh valve port 22; the third protrusion and the valve body 1 form the second valve port 23; the oil inlet 5 and the fourth oil passage 10 are both connected to the second valve port 23; the fourth protrusion and the valve body 1 form the fourth valve port 24; the sixth oil passage 12 is connected to the fourth valve port 24; the logic valve and the valve body 1 form the third valve port 25; and the fifth oil passage 11 is connected to the third valve port 25.

[0068] The beneficial effects of adopting the above-mentioned further technical solutions are: the protrusion and valve port settings facilitate the opening and closing of the oil passage, and facilitate the realization of different control requirements through the mutual cooperation of valve cores such as the main valve, unloading valve and logic valve. The main valve is linked with the unloading valve, logic valve and other valves through hydraulic control to realize the connection of different oil circuits. The hydraulic control can improve control sensitivity, increase flow capacity and expand the applicability of the valve.

[0069] like Figures 1 to 7 As shown, the first protrusion, the second protrusion, the third protrusion, and the fourth protrusion are all cylinders to achieve the valve port sealing function; the main valve core 2 is located between the logic valve core 3 and the unloading valve core 4.

[0070] The beneficial effects of adopting the above-mentioned further technical solution are: the protrusion is cylindrical, which facilitates the closure of the protrusion and the opening of the corresponding valve port, thereby improving the stability and reliability of the control valve assembly. The main valve core is located between the logic valve core and the unloading valve core, which facilitates the oil passage design of the main valve, logic valve, and unloading valve, improves integration, simplifies the oil passage connection method, and reduces costs.

[0071] This utility model provides an embodiment of a lifting control valve assembly, which can be a lifting control valve with high control precision, sensitive action, and low leakage. It can also be a hydraulic control valve used for lifting control of mechanical force-operated lifting devices. Specifically, it includes: a main valve core, a logic valve, a logic valve spring, an unloading valve core, an unloading valve spring, and a valve body, etc.

[0072] like Figure 1 and Figure 2 As shown, when the main valve core is in the neutral position, the hydraulic oil in the control spring chamber of the unloading valve core is connected to the T1 oil port (first oil outlet) through the oil passage hole (first oil passage) and the main valve core. The spring chamber (the side of the unloading valve chamber with the unloading valve spring) is pressureless. The pressure oil from the P port (oil inlet) acts on the right end of the unloading valve core. Since the unloading valve core spring chamber is connected to the T1 port (first oil outlet) for unloading, the pressure overcomes the unloading valve spring and opens the unloading valve port (first valve port) for unloading. The stiffness of the unloading valve spring is very small, and it is only necessary to realize the reset function of the valve core. Therefore, the neutral unloading pressure P is very small, and the power loss is small. Also, because most of the pressure oil does not pass through the main valve core during neutral unloading, it returns directly to the oil tank through the unloading valve, and the pressure loss along the way is small. At this time, the right spring chamber of the logic valve is connected to the load port C through the oil passage (sixth oil passage), valve port (fourth valve port), and oil passage (seventh oil passage). The pressure in the spring chamber is equal to the load pressure. Under the combined action of the spring force and the load pressure, the logic valve reliably closes the valve port (third valve port), so that the machine is kept in the set position. At this time, the machine is in a neutral and stationary state.

[0073] like Figure 3 and Figure 4 When the valve core moves to the right and is in the raised position, the hydraulic oil in the control spring chamber of the unloading valve core passes through the oil passage hole (first oil passage) and the oil passage inside the main valve core (second oil passage). The valve core oil passage (third oil passage) is connected to the pressure oil at port P (inlet), guiding the pressure oil to the spring chamber of the unloading valve core. At this time, the pressure on the left side of the unloading valve core is greater than the pressure on the right side under the combined action of spring force and hydraulic pressure, reliably closing the oil ports (first valve port) of port P (inlet) and port T2 (second outlet). The pressure oil at port P (inlet) passes through the open valve port (second valve port), through the oil passage (fourth oil passage) and the oil passage (fifth oil passage) to the left side of the logic valve. At this time, the right spring chamber of the logic valve is connected to port C (load port) through the oil passage (sixth oil passage), the main valve core port (fourth valve port), and the oil passage (seventh oil passage). Port C (load port) is also connected to the lower chamber of the lifting cylinder. The pressure at port C (load port) is the cylinder load pressure. When the pressure on the left side of the logic valve, i.e., the pressure at port P (oil inlet), is greater than the load pressure at port C (load port), the valve port (third valve port) of the logic valve can be opened. Port P (oil inlet) is then connected to port C (load port) through the valve port (second valve port), the oil passage (fourth oil passage), the oil passage (fifth oil passage), and the valve port (third valve port). Pressurized oil enters the lifting cylinder, pushing the cylinder to move and realizing the lifting function.

[0074] like Figure 5 and Figure 6 As shown, when the main valve core is moved to the left, it is in the lowered position. The hydraulic oil in the control spring chamber of the unloading valve core is connected to port T1 (first outlet) through the oil passage (first oil passage) and the oil port formed by the main valve core and the valve body (fifth valve port). The pressure in the spring chamber is unloaded, and the unloading valve core moves to the left under the action of the pressure oil on the right side, opening the valve port (first valve port). The P port (oil inlet) is connected to T2 (second oil outlet), and the pressure oil is unloaded at low pressure. At the same time, the leftward movement of the main valve core reliably closes the valve port (second valve port) and opens the valve port (seventh valve port). At this time, the right spring chamber of the logic valve is connected to the Dr oil port (Drainport) through the oil passage (sixth oil passage), the fixed throttling hole (throttling hole) on the main valve core, the main valve core oil passage (eighth oil passage), and the valve body oil passage (ninth oil passage), and returns directly to the oil tank. With no pressure in the spring chamber, the logic valve core moves to the right under the load pressure at port C (load port), opening the third valve port. Port C (load port) connects to port T1 (first oil outlet) via the third valve port, oil passage (fifth oil passage), oil passage (fourth oil passage), and the seventh valve port. The pressure oil from the lifting cylinder returns to the oil tank through this path via port T1 (first oil outlet), causing the machine to descend.

[0075] The mid-position unloading system employs a main valve hydraulically controlled unloading valve structure, resulting in low pressure loss. The descending valve utilizes a logic valve structure, hydraulically controlled via the main valve, ensuring reliable sealing and minimal leakage. The main valve core (main valve spool) incorporates control oil passages and throttling mechanisms to control the unloading valve and logic valve through hydraulic control, simplifying the control method and achieving high precision. A throttling groove is incorporated at the valve orifice of the main valve spool to enhance the micro-motion performance and control accuracy of the main valve.

[0076] In addition, this utility model also provides a lifting system, including the aforementioned lifting control valve assembly.

[0077] In addition, this utility model also provides a tractor, including the aforementioned lifting system.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A lift control valve assembly, characterized in that, include: The valve comprises a valve body, a main valve, a logic valve, and an unloading valve. The main valve contains a main valve core, the logic valve contains a logic valve core, and the unloading valve contains an unloading valve core. The main valve core, the logic valve core, and the unloading valve core are all slidably mounted in the valve body. When the main valve core is in the neutral position, it is connected to the logic valve and the unloading valve through a first hydraulic control combination channel. When the main valve core is in the right position, it is connected to the logic valve and the unloading valve through a second hydraulic control combination channel. When the main valve core is in the left position, it is connected to the logic valve and the unloading valve through a third hydraulic control combination channel.

2. The lifting control valve assembly according to claim 1, characterized in that, The valve body is provided with an oil inlet, a first oil outlet, a second oil outlet, a load port, a main valve core cavity for installing the main valve core, a logic valve cavity for installing the logic valve core, an unloading valve cavity for installing the unloading valve core, a first oil passage, a fourth oil passage, a fifth oil passage, a sixth oil passage, a seventh oil passage, a ninth oil passage, and an oil drain port. The main valve core is provided with a second oil passage, a third oil passage and an eighth oil passage, which are connected in sequence; the main valve core is provided with a throttling orifice, which is connected to the eighth oil passage, and the ninth oil passage is connected to the drain port and the main valve core cavity respectively. The oil inlet and the first oil outlet are both connected to the main valve core cavity, the second oil outlet is connected to the unloading valve cavity, and the load port is connected to the logic valve cavity. The unloading valve chamber is connected to the main valve core chamber through the first oil passage; the fourth oil passage is connected to the fifth oil passage, the main valve core chamber is connected to the fourth oil passage, the logic valve chamber is connected to the fifth oil passage, and the logic valve chamber is connected to the main valve core chamber through the sixth oil passage and the seventh oil passage; A logic valve spring is provided in the logic valve cavity, and the logic valve core is slidably installed in the logic valve cavity through the logic valve spring; an unloading valve spring is provided in the unloading valve cavity, and the unloading valve core is slidably installed in the unloading valve cavity through the unloading valve spring.

3. A lifting control valve assembly according to claim 2, characterized in that, When the main valve core is in the neutral position, the first hydraulic control combination channel includes: a channel in the unloading valve chamber that connects the side with the unloading valve spring, the first oil passage, and the first oil outlet in sequence; a channel that connects the oil inlet and the second oil outlet in sequence; and a channel in the logic valve chamber that connects the side with the logic valve spring, the sixth oil passage, the seventh oil passage, and the load port in sequence.

4. A lifting control valve assembly according to claim 2, characterized in that, When the main valve core is in the right position, the second hydraulic control combination channel includes: a channel in the unloading valve chamber that connects the side with the unloading valve spring, the first oil passage, the second oil passage, the third oil passage, and the oil inlet in sequence; a channel in the logic valve chamber that connects the oil inlet, the fourth oil passage, the fifth oil passage, and the side without the logic valve spring in sequence; a channel in the logic valve chamber that connects the side with the logic valve spring, the sixth oil passage, the seventh oil passage, and the load port in sequence; and a channel in the logic valve chamber that connects the oil inlet, the fourth oil passage, the fifth oil passage, and the load port in sequence.

5. A lifting control valve assembly according to claim 2, characterized in that, When the main valve core is in the left position, the third hydraulic control combination channel includes: a channel in the unloading valve chamber that connects the unloading valve spring on one side, the first oil passage and the first oil outlet in sequence; a channel that connects the oil inlet and the second oil outlet in sequence; a channel in the logic valve chamber that connects the logic valve spring on one side, the sixth oil passage, the throttle orifice, the eighth oil passage, the ninth oil passage and the drain port in sequence; and a channel that connects the load port, the fifth oil passage, the fourth oil passage and the first oil outlet in sequence.

6. A lifting control valve assembly according to claim 2, characterized in that, The first oil outlet, the second oil outlet, and the drain outlet are all connected to an oil tank; the load port is connected to the lower chamber of the lifting cylinder.

7. A lifting control valve assembly according to claim 2, characterized in that, The unloading valve core is provided with a first protrusion, which forms a first valve port with the valve body. The second oil outlet is connected to the oil inlet through the first valve port. The main valve core is provided with a second, a third, and a fourth protrusion. The third protrusion is located between the second and fourth protrusions. The second protrusion and the valve body form a fifth and a seventh valve port. The first oil outlet is connected to both the fifth and seventh valve ports. The first oil passage is connected to the fifth valve port. The fourth oil passage is connected to the seventh valve port. The third protrusion and the valve body form a second valve port. The oil inlet and the fourth oil passage are both connected to the second valve port. The fourth protrusion and the valve body form a fourth valve port. The sixth oil passage is connected to the fourth valve port. The logic valve and the valve body form a third valve port. The fifth oil passage is connected to the third valve port.

8. A lifting control valve assembly according to claim 7, characterized in that, The first protrusion, the second protrusion, the third protrusion, and the fourth protrusion are all cylindrical to achieve the valve port sealing function; the main valve core is located between the logic valve core and the unloading valve core.

9. A lifting system, characterized in that, Includes a lift control valve assembly as described in any one of claims 1 to 8.

10. A tractor, characterized in that, The lifting system includes the one described in claim 9 above.

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