Tractor multi-way valve, tractor and hydraulic control method thereof

Abstract

This application relates to the field of agricultural machinery, specifically a tractor multi-way valve, a tractor, and its hydraulic control method. The tractor multi-way valve includes an inlet and return oil connection; a priority working connection, including a main directional valve and a constant flow valve downstream of the main directional valve. The constant flow valve includes an adjustable throttle valve and a pressure compensation valve. The working oil from the main inlet flows through the main directional valve to the constant flow valve downstream, and is output to the main valve inlet upstream of the main directional valve through the throttling output port of the adjustable throttle valve. In this tractor multi-way valve, the added constant flow valve can be a combination of an adjustable throttle valve and a pressure compensation valve. The valve components used are relatively common, few in number, low in cost, and have good performance. The constant flow valve is installed downstream of the main directional valve in the priority working connection, occupying less installation space and having a more compact structure. The constant flow valve can ensure a constant flow output in the priority working connection, achieving uniform operation of the implements, unaffected by changes in the working port load or inlet oil flow.

Description

Technical Field

[0001] This application belongs to the field of agricultural machinery, specifically relating to a tractor multi-way valve, a tractor, and a hydraulic control method thereof. Background Technology

[0002] The multi-way valve in a tractor is a core control component in the tractor's hydraulic system. It distributes the hydraulic pump's output oil to multiple actuators, such as the lifting cylinder, implement hydraulic cylinder, and implement motor, to precisely control the lifting, lowering, rotating, holding, or floating actions of the implements. Existing tractor multi-way valves, when multiple actuators are operating, typically allow flow to flow towards the side with the lower load, which is detrimental to the consistency of flow across the core implement's working links. For agricultural machinery like tractors, operational stability is crucial. Furthermore, even when a single working link is operating, inconsistent throttle settings result in significant flow fluctuations, increasing operational unevenness and the operator's difficulty.

[0003] Specifically, in existing tractor multi-way valves, the main oil inlets of each working link are typically hydraulically connected to the main oil circuit in parallel. This makes it difficult to distribute flow as needed when controlling combined actions; flow always preferentially flows to the working ports of lighter-loaded working links, resulting in slow operation of heavily loaded actuators. When the multi-way valve controls a single working link to perform an individual action, the actuator's operating speed is easily affected by both load and throttle position, leading to poor operational stability. Summary of the Invention

[0004] The purpose of this application is to provide a tractor multi-way valve, a tractor, and a hydraulic control method thereof, so as to integrate the constant flow output function of the priority working link in a miniaturized and low-cost manner, thereby improving the tractor's operating performance.

[0005] To achieve the above objectives, this application provides a tractor multi-way valve, comprising: The oil inlet and outlet connection includes the main oil inlet; The priority working link includes a main directional valve and a constant flow valve disposed after the main directional valve. The constant flow valve includes an adjustable throttle valve and a pressure compensation valve for stabilizing the pressure difference between the two ends of the adjustable throttle valve. The working oil at the main inlet flows through the constant flow valve after the main directional valve and is output to the main valve inlet on the front side of the main directional valve through the throttling output port of the adjustable throttle valve.

[0006] In some embodiments, the first hydraulically controlled end of the pressure compensation valve is connected to the inlet end of the adjustable throttle valve via a first pilot oil passage, and the second hydraulically controlled end of the pressure compensation valve is connected to the outlet end of the adjustable throttle valve via a second pilot oil passage; wherein, the first pilot oil passage is provided with a first damping, and the second pilot oil passage is provided with a second damping.

[0007] In some embodiments, the tractor multi-way valve further includes: Several subsequent working links are located after the valves of the priority working links, and the downstream bypass port of the pressure compensation valve is hydraulically connected to the main valve inlet of several of the subsequent working links.

[0008] In some embodiments, the main directional valve is provided with a main valve oil port that extends through the front and rear. The front end of the main valve oil port is connected to the main oil inlet of the inlet and return oil connection. The rear end of the main valve oil port is hydraulically connected to the constant flow valve. The main valve oil inlet of the rear working connection is hydraulically connected to the rear end of the main valve oil port at the middle valve position of the main directional valve in the priority working connection.

[0009] In some embodiments, the main directional valve includes a working valve position and an intermediate valve position. In the working valve position, the rear end of the main valve port is hydraulically connected to the constant flow valve and is cut off from the main valve port in the subsequent working position. In the intermediate valve position, both the constant flow valve and the main valve port in the subsequent working position are hydraulically connected to the rear end of the main valve port.

[0010] In some embodiments, the tractor multi-way valve further includes: Several prior working links are located before the valve of the priority working link, and the oil passage of the main valve of the prior working link is hydraulically connected to the oil passage of the main valve of the priority working link.

[0011] In some embodiments, the main directional valve includes: The first intermediate valve position is the O-type neutral position function; The second intermediate valve position is a Y-type intermediate position function.

[0012] In some embodiments, the tractor multi-way valve is a plate-type multi-way valve including the inlet / return oil connection, several working connections, and the tail connection. The inlet / return oil connection, several working connections, and the tail connection are all modular unit structures and are arranged in a sequentially stacked manner along the front-to-back direction.

[0013] This application also provides a tractor that includes the aforementioned tractor multi-way valve.

[0014] This application also provides a hydraulic control method for a tractor, including: Identify the actuators that require constant flow supply, and designate the working links in the tractor multi-way valve corresponding to the actuators as the priority working links; The constant flow valve is arranged after the main directional valve of the priority working link. The constant flow valve includes an adjustable throttle valve and a pressure compensation valve for stabilizing the pressure difference between the two ends of the adjustable throttle valve. The working oil in the main inlet of the tractor multi-way valve flows through the main reversing valve to the constant flow valve after the valve. The constant flow hydraulic oil output from the throttling outlet of the adjustable throttle valve flows through the main directional valve back to the main valve inlet on the front side of the main directional valve. When the flow rate of the working oil at the main inlet is greater than the constant flow rate of the hydraulic oil output from the throttling outlet, the excess flow rate is directed through the bypass port of the pressure compensation valve to the main valve inlet of the subsequent working link, located after the priority working link valve.

[0015] In the tractor multi-way valve of this application, the added constant flow valve can be a combination of an adjustable throttle valve and a pressure compensation valve, which reduces the number of valve components used, lowers cost, and improves performance. The constant flow valve is installed downstream of the main directional valve of the priority working link, rather than integrated around the inlet and return oil lines, thus occupying less installation space and resulting in a more compact structure. The constant flow valve has strong installation flexibility; when installed downstream of the main directional valve of the required working link, the working oil at the main inlet of the inlet and return oil lines can flow through the main directional valve to the constant flow valve downstream, and then output a constant flow rate to the main valve inlet upstream of the main directional valve through the throttling output port of the adjustable throttle valve. This ensures a constant flow output in the priority working link, achieving uniformity of implement operation, improving main engine performance, and is unaffected by changes in working port load or inlet flow rate.

[0016] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without any inventive effort. In the drawings: Figure 1 This is a schematic diagram of the structure of a multi-way valve for a tractor in the prior art; Figure 2 The present invention provides a hydraulic schematic diagram of a tractor multi-way valve according to a specific embodiment of the present application. Figure 3 for Figure 2Hydraulic schematic diagram of the priority working link in the middle; Figure 4 The present invention provides a hydraulic schematic diagram of a tractor multi-way valve according to another embodiment of the present application. Figure 5 The flow characteristic diagram of the constant flow valve throttling output according to this application; Figure 6 A schematic diagram of the modular structure of a tractor multi-way valve according to a specific embodiment of this application; Figure 7 for Figure 6 The AA cross-sectional view in the figure shows the internal valve body structure of the constant flow valve; Figure 8 This is a schematic diagram of the modular structure of a tractor multi-way valve according to another embodiment of this application.

[0018] Explanation of reference numerals in the attached figures 1. Priority working link; 2. Subsequent working link; 3. First working link; 4. Main relief valve; 5. Valve stem assembly; 6. Main directional valve; 7. Main oil inlet; 8. Main oil return port; 9. Oil inlet / outlet connection; 10. Adjustable throttle valve; 11. Throttling output port; 12. Throttling port; 13. First damper; 14. Pressure compensation valve; 15. Constant flow valve inlet; 16. Pressure compensation valve core port; 17. Valve bypass port; 18. Spring chamber; 19. Second damping; 20. Oil quantity control valve; 21. Constant flow valve; P1. Main valve inlet; C. Main valve outlet. Detailed Implementation

[0019] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0020] This application proposes a novel multi-way valve for tractors. For example... Figure 2 , Figure 3 , Figure 6 As shown, in one specific embodiment, the tractor multi-way valve includes: Oil inlet / outlet connection 9, including main oil inlet 7; The priority working link 1 includes a main directional valve 6 and a constant flow valve 21 located downstream of the main directional valve 6. The constant flow valve 21 includes an adjustable throttle valve 10 and a pressure compensation valve 14 for stabilizing the pressure difference between the two ends of the adjustable throttle valve 10. The working oil at the main inlet 7 flows through the main directional valve 6 to the constant flow valve 21 after the valve, and is output to the main valve inlet P1 on the front side of the main directional valve 6 through the throttling output port 11 of the adjustable throttle valve 10.

[0021] The tractor multi-way valve of this application can achieve constant flow output function. To this end, an innovative hydraulic design is proposed, in which a constant flow valve functional unit composed of a pressure compensation valve 14 and an adjustable throttle valve 10 is arranged after the valve of the required priority working link 1. In particular, the inventors of this application, through research on the system structure of tractor multi-way valves and user needs, designed the above-mentioned tractor multi-way valve, which adopts flow priority distribution to ensure constant flow output of priority working link 1, so as to achieve uniformity of agricultural implement operation, thereby being unaffected by changes in working port load and oil inlet flow, and effectively improving the performance of the main unit.

[0022] Specifically, in traditional tractor multi-way valve designs, during combined operation, the flow tends to flow towards the side with lower load, which is detrimental to the consistency of flow in the core implement's working links. Furthermore, during individual operation, although only one working link is active, inconsistent throttle positions result in significant flow fluctuations, increasing the unevenness of operation and the difficulty of operator control. While there are targeted improvements, such as using load feedback design to control the oil supply to the working links, these additional oil quantity control valves 20 are numerous and large, typically arranged around the inlet and return oil links 9, occupying considerable space. Figure 1 As shown.

[0023] Therefore, in the design process of the tractor multi-way valve of this application, the above-mentioned constant flow valve 21 is specially set after the main directional valve 6 of the required working link, which can be easily connected to the main directional valve 6. The working link with the integrated constant flow valve 21 becomes the priority working link, which can give priority to output a basically constant hydraulic flow.

[0024] The constant flow valve 21 of this application includes an adjustable throttle valve 10 and a pressure compensation valve 14 for stabilizing the pressure difference across the adjustable throttle valve 10. It employs a very simple valve design, including only two basic valve components: the adjustable throttle valve 10 for regulating flow and the pressure compensation valve 14 for maintaining a constant pressure difference across the adjustable flow valve 10. The required flow rate can be adjusted by changing the opening of the adjustable flow valve 10. Furthermore, the presence of the pressure compensation valve 14 stabilizes the pressure difference across the adjustable flow valve 10, resulting in a stable output flow rate. Therefore, the constant flow valve 21 of this application has fewer valve components, a smaller size and weight, and is installed downstream of the required working valve. For a multi-way valve, this design offers a compact installation structure and does not occupy lateral space. Figure 6 , Figure 8 As shown.

[0025] Comparable, Figure 1 This paper demonstrates the installation structure and layout of the oil quantity control valve 20 in a prior art tractor multi-way valve. The working links are stacked along the front-to-back direction, and the main body of the oil quantity control valve 20 is generally located around the inlet and return oil links 9. The structure of the oil quantity control valve 20 is generally quite complex, with many valve components. Some valve components need to connect to the oil ports of the working links, and therefore are placed close to the working links. The valve components and oil ports are connected by pipes. This structural layout makes the multi-way valve appear loose and bulky, and the pipes and other components also encroach on lateral space. Furthermore, due to the numerous integrated valve components and complex structure, the oil quantity control valve 20 can only be designed for specific applications, resulting in poor versatility.

[0026] In such Figure 6 , Figure 8 The tractor multi-way valve of this application also adopts a plate structure, that is, the tractor multi-way valve is a plate multi-way valve including an inlet / return oil coupling 9, several working couplings and a tail coupling. The inlet / return oil coupling 9, several working couplings and the tail coupling are all modular unit structures and are arranged in a sequentially stacked manner along the front-to-back direction, such as... Figure 6 , Figure 8 As shown. This plate-type structure combined with modular unit design not only facilitates universal design and makes it easy to connect the constant flow valve 21 with the main directional valve in the working link, but also the addition of the constant flow valve 21 only results in an increase in thickness in the front and rear directions, making the structure more compact compared to... Figure 1 The oil quantity control valve 20 shown is installed on the inlet / outlet oil connection or tail connection. The constant flow valve 21 of this application occupies less space, has a more compact structure, does not require too many pipeline connections, and occupies less space.

[0027] After the working link with the integrated constant flow valve 21 becomes the priority working link 1, the working oil at the main inlet 7 of the inlet and return oil link 9 can pass through the main valve overlet port C shown in the figure, flow through the main directional valve 6 to the constant flow valve 21 after the valve, and then flow back to the main valve inlet P1 on the front side of the main directional valve 6 through the throttling output port 11 of the adjustable throttle valve 10, and then flow to the working port A1 or B1 of the priority working link 1 to drive the actuator to move.

[0028] When the throttling output port 11 flows back to the main valve inlet P1 on the front side of the main directional valve 6, a through hole can also be provided at the valve body end of the main directional valve 6 of the priority working link 1 as a flow passage hole, so as to avoid the structure being loose and taking up space due to the connection pipe.

[0029] In this embodiment, the adjustable throttle valve 10 employs a throttle valve with a conical valve core, thereby achieving linear flow regulation, i.e., precise control of constant flow output. This type of throttle valve with a conical valve core is relatively common and low in cost; its body can be installed in… Figure 7The opening area of ​​the throttling orifice 12 can be precisely adjusted by turning an external adjustment knob inside the valve body of the constant flow valve 21 shown. Of course, the adjustable throttling valve 10 is not limited to the throttling valve with a conical valve core; other types of adjustable flow valves are also within the scope of protection of this application.

[0030] This embodiment also uses a pressure compensation valve 14 with a simple structure, such as Figure 3 As shown, the first hydraulic control end of the pressure compensation valve 14 (the upper end of the valve body in the figure) is connected to the oil inlet end of the adjustable throttle valve 10 through the first pilot oil passage, and the second hydraulic control end of the pressure compensation valve 14 (the upper end of the valve body in the figure, i.e., the spring cavity 18) is connected to the oil outlet end of the adjustable throttle valve 10 through the second pilot oil passage; wherein, the first pilot oil passage is provided with a first damping 13, and the second pilot oil passage is provided with a second damping 19.

[0031] The pressure compensation valve 14 is a valve component well known to those skilled in the art. The pressure difference between its two control ends controls the displacement of its valve core, thereby controlling the valve opening. In other words, the pressure difference between the first and second hydraulic control ends drives the valve core to move. Figure 3 As shown, when the pressure at the first hydraulic control end is much greater than the pressure at the second hydraulic control end, the pressure compensation valve 14 is fully open; conversely, when the pressure at the second hydraulic control end is much greater than the pressure at the first hydraulic control end, the pressure compensation valve 14 is completely closed. When the pressure difference between the two ends is within the range of the above two states, the pressure compensation valve 14 is partially open, and the pressure compensation valve core port 16 is partially opened, allowing a portion of the oil at the constant flow valve inlet 15 to flow through the pressure compensation valve core port 16 to the downstream bypass port 17, and then to the downstream working link 2.

[0032] The purpose of setting dampers in the pilot oil circuit of the pressure compensation valve 14 is to improve the stability of the pressure difference. For example, the setting of the first damper 13 can prevent the oil at the inlet of the adjustable throttle valve 10 from impacting the first hydraulic control end of the pressure compensation valve 14, thus making the oil pressure of the pilot oil entering the first hydraulic control end more stable. Similarly, the setting of the second damper 19 can also make the oil pressure of the pilot oil entering the second hydraulic control end more stable. Of course, the type and number of dampers can be set as needed, for example, the second pilot oil circuit shown in the figure has two dampers connected in series.

[0033] See Figure 2 , Figure 3 Several subsequent working links 2 are connected downstream of the valve in the priority working link 1. The bypass port 17 of the pressure compensation valve 14 is hydraulically connected to the main valve inlet of the several subsequent working links 2, so that the overflow oil from the priority working link 1 can be used by the subsequent working links 2, and of course, it can also be returned. In this way, the oil entering the multi-way valve prioritizes the use of the priority working link 1, and then the excess oil is supplied to the subsequent working links 2.

[0034] See Figure 2 , Figure 3 , Figure 7 When hydraulic oil enters the valve body from the constant flow valve inlet 15, it enters the adjustable throttle valve 10, and after being throttled by the throttle port 12, it reaches the throttle output port 11, outputting a stable constant flow. Then, it flows back to the main valve inlet P1 before the main directional valve 6, and then, depending on the directional valve position, flows to the corresponding working port A1 or B1. If the inflow rate from the constant flow valve inlet 15 is greater than the constant flow rate output from the throttle output port 11, the excess oil can be transferred through the pressure compensation valve core port 16 to the downstream bypass port 17, and then output to all subsequent working connections 2.

[0035] For the specific structural design of the constant flow valve 21, please refer to... Figure 7 The pressure compensation valve core port and throttling groove can be designed on the mating surface between the valve core and the valve body. Their shape and size are optimized to effectively reduce hydraulic shock and improve flow characteristics. Various damping mechanisms can increase the dynamic stability of flow output. In addition, the outlet of the constant flow valve is connected to the throttling output port 11 of the adjustable throttling valve 10, and the downstream bypass port 17 is connected to the pressure compensation valve core port 16. In terms of specific structural design, by connecting the oil port and setting the oil passage inside the valve body, the constant flow valve 21 can fit more tightly with the main directional valves on the front and rear sides.

[0036] exist Figure 7 In the structural design, the key components for achieving constant flow output include the adjustable throttle valve 10, the valve core and body of the pressure compensation valve 14, and the design of the damping. The design of these components directly affects the performance of the entire system. The pressure compensation valve core is the core component for controlling the differential pressure at the throttle outlet. It requires high dimensional accuracy and surface roughness to ensure good response characteristics during operation.

[0037] Specifically, the valve core of the pressure compensation valve 14 can be made of high-strength alloy steel with a hardened surface to improve wear resistance and corrosion resistance. The valve body of the pressure compensation valve can be made of ductile iron, which has high strength and toughness. At the same time, the precision of the internal flow channel is ensured by precision casting process, and copper damping can be used to provide good sealing and machining performance.

[0038] In addition, in comparison Figure 6 and Figure 8 These are two embodiments of the tractor multi-way valve described in this application. The difference is that... Figure 8 The valve assembly is more compact in the working link stacking direction, meaning the inlet / return oil link 9 and the priority working link 1 are closer together. In actual installation, existing tractor multi-way valves are larger in length and width, especially in the working link stacking direction. Therefore, Figure 6The tractor multi-way valve shown can maintain the same length as existing tractor multi-way valves, but is smaller in width to fit the existing installation space of multi-way valves on tractors. Figure 8 The tractor multi-way valve shown is more compact in both length and width, saving more space in the existing multi-way valve installation space for other uses.

[0039] Combination Figure 2 , Figure 3 , Figure 7 As can be seen, in this embodiment, as an example, the main directional valve 6 switches positions under the pull of the valve stem assembly 5. When switched to the working position, the hydraulic oil in the main inlet 7 passes through the main directional valve 6 to the constant flow valve inlet 15 of the constant flow valve 21. The hydraulic oil stabilizes the pressure difference across the throttle port 12 through the pressure compensation valve 14, and improves the stability of the pressure difference through the first damper 13 and the second damper 19, ensuring the flow rate of the throttle output port 11 is stable. The opening area of ​​the throttle port 12 can be adjusted by the adjustable throttle valve 10, thereby adjusting the flow rate and achieving adjustable constant flow output flow rate. When the flow rate at the constant flow valve inlet 15 is greater than the flow rate through the throttle port 12, the excess flow rate will overflow from the pressure compensation valve core port 16 and flow to the downstream working link 2 through the valve bypass port 17 connected to the pressure compensation valve core port 16. Throttling port 12 is connected to throttling output port 11. Throttling output port 11 directly supplies oil to the main valve inlet P1 before the main directional valve 6, so that the working link of the main directional valve 6 has a stable flow function.

[0040] In this embodiment, through testing, the final result is obtained. Figure 5 The flow characteristic diagram for constant flow output is shown. Figure 5 In the diagram, the left side of position 0 on the horizontal axis represents that the oil pressure at the bypass port 17 is greater than the oil pressure at the throttling output port 11, while the right side of position 0 represents that the oil pressure at the bypass port 17 is less than the oil pressure at the throttling output port 11. It can be seen that regardless of the relationship between the throttling output oil pressure and the overflow output oil pressure, and regardless of how the opening area of ​​the throttling port 12 is adjusted by turning the external adjustment knob (within the range of 1 to 4 turns), the flow rate output by the constant flow valve 21 is stable, reliable, and meets the design requirements.

[0041] See Figure 2 , Figure 3 , Figure 6To achieve the sequential transmission of hydraulic oil from the inlet / return oil connection 9, the priority working connection 1 (including the constant flow valve 21), and the subsequent working connection 2, the main directional valve 6 of the priority working connection 1 is equipped with a through-port C. The front end of the main valve through-port C is connected to the main inlet 7 of the inlet / return oil connection 9, and the rear end of the main valve through-port C is hydraulically connected to the constant flow valve 21. In the subsequent working connection 2, the main valve inlet is hydraulically connected to the rear end of the main valve through-port C at the intermediate valve position of the main directional valve 6 of the priority working connection 1. The design of the main valve through-port C facilitates the supply of oil to the constant flow valve 21 downstream of the valve, and also allows hydraulic oil to be transmitted to the next working connection from the intermediate position of the main directional valve. In the next working connection, its main valve through-port is connected to its main inlet.

[0042] See Figure 2 , Figure 3 In this embodiment, the main directional valve 6 of the priority working link 1 includes a working valve position and an intermediate valve position. In the working valve position, the rear end of the main valve oil port C is hydraulically connected to the constant flow valve 21 and is cut off from the main valve oil port of the subsequent working link. That is, all hydraulic oil is transmitted to the constant flow valve 21, and only the overflow oil of the constant flow valve 21 is transmitted to the next working link, thereby ensuring the constant flow oil output of the priority working link 1. In the intermediate valve position of the main directional valve 6, the constant flow valve 21 and the main valve oil port of the subsequent working link 2 are both hydraulically connected to the rear end of the main valve oil port C. At this time, the priority working link 1 is not working, and the hydraulic oil can pass through the priority working link 1 and be directly transmitted to the next working link.

[0043] In particular, Figure 3 The main directional valve 6 shown has an intermediate valve position, namely: The first intermediate valve position is the O-type neutral position function; The second intermediate valve position is a Y-type intermediate position function.

[0044] In the first intermediate valve position (i.e. Figure 3 The second valve position (leftmost position) of the main directional valve 6, due to its O-type neutral position function, allows the actuator connected to working ports A1 and B1 to be fixed in any position and remain stationary. In the second intermediate valve position (i.e.... Figure 3 The rightmost valve position of the main directional valve 6 (using a Y-type neutral position function) allows the working ports A1 and B1 to be interconnected, while the connected actuator is in a floating state. Of course, the valve position and number of valve ports of the main directional valve 6 can be set as needed.

[0045] See Figure 4 Another embodiment of the tractor multi-way valve also includes several prior working links 3, which are located before the valve of the priority working link 1. The main valve port of the prior working link 3 is hydraulically connected to the main valve port C of the priority working link 1. Therefore, with prior working links 3 and subsequent working links 2, it means that the priority working link 1 can be any working link, and is not limited to it. Figure 2 The first working link is shown. In other words, any working link can be used as a priority working link. When there is a priority working link 3, the hydraulic oil from the main inlet 7 of the inlet / return link 9 can first pass through several priority working links 3 before connecting to the priority working link 1.

[0046] In summary, the tractor multi-way valve of this application adds a constant flow valve 21 to the rear end of the main directional valve, which can realize the constant flow output of the working link and the flow rate is adjustable, so as to stabilize the flow of priority and important actions in the hydraulic system, without being affected by the simultaneous operation of multiple links, the size of the throttle, and the load.

[0047] In addition, this application also provides a tractor that includes the aforementioned tractor multi-way valve.

[0048] Among them, the priority working link 1 is particularly suitable for controlling the actuator to perform the sowing and fertilizing operations of the tractor, and of course it can also be used for any other constant flow output operation. When the tractor performs sowing, fertilizing and other actions, the multi-way valve switches to the working valve position (oil exits from working port A1 or B1). After the hydraulic oil enters the constant flow valve 21, it is pressure compensated and prioritized to supply oil to the priority working link 1. It is not affected by the workload or fluctuations in the oil flow. The excess flow flows to other subsequent working links 2. By adjusting the opening of the adjustable throttle valve 10, the priority output flow is controlled, thereby precisely controlling the working speed of the working mechanism.

[0049] The tractor multi-way valve of this application integrates a constant flow output function, significantly reducing the overall size and weight of the system. It also adopts a modular design concept, with the constant flow valve 21 arranged after the working link that requires constant flow output, so that the constant flow output function can be set for any link. The tractor multi-way valve of this application is smaller in size and more compact in structure, making it easier to install and use. Combined with simulation analysis, the damping design of several damping circuits in the pressure compensation method 14 improves the stability of constant flow output. The valve core conical surface design of the adjustable throttle valve enables linear flow change during valve core opening, thereby effectively avoiding hydraulic shock.

[0050] Meanwhile, this application optimizes the adjustable throttling valve core and adopts several sets of damping balance designs, making constant flow regulation more precise, stable, and responsive, meeting the high-efficiency operation requirements of modern agricultural machinery. Furthermore, in terms of user experience, the design of the constant flow valve 21 positioned at the rear of the main directional valve body simplifies the overall valve body space and allows for arbitrary placement of the constant flow valve behind the valve body, achieving constant flow output for the working link to which the valve body is located, further enhancing the ease of use of the multi-way valve.

[0051] In addition, this application also provides a hydraulic control method for a tractor, comprising: Identify the actuators that require constant flow supply, and designate the corresponding actuator working link in the tractor multi-way valve as the priority working link 1; The constant flow valve 21 is arranged after the main directional valve 6 of the priority working link 1. The constant flow valve 21 includes an adjustable throttle valve 10 and a pressure compensation valve 14 for stabilizing the pressure difference between the two ends of the adjustable throttle valve 10. The working oil from the main inlet 7 of the tractor's multi-way valve's oil inlet and return valve 9 flows through the main directional valve 6 to the constant flow valve 21 downstream of the valve; The constant flow hydraulic oil output from the throttling output port 11 of the adjustable throttle valve 10 flows back to the main valve inlet P1 on the front side of the main directional valve 6 through the main directional valve 6. When the flow rate of the working oil at the main inlet 7 is greater than the constant flow rate of hydraulic oil output at the throttle output port 11, the excess flow rate is directed through the bypass port 17 of the pressure compensation valve 14 to the main valve inlet of the rear working link 2, which is located after the valve of the priority working link 1.

[0052] After identifying the priority working link 1, the method of this application only requires adding a constant flow valve 21 after the selected priority working link 1. At the same time, the oil port connection and the oil circuit layout inside the valve are properly arranged. The amount of modification work is small, but it can achieve the constant flow output of the priority working link 1, and on the basis of ensuring the constant flow output of the priority working link 1, the oil supply to the subsequent working link 2 is guaranteed.

[0053] This application's method demonstrates significant advantages in several aspects, particularly in improving tractor handling performance and enhancing system functionality. Regarding handling performance, the constant flow valve arrangement is simplified and modular, allowing it to be installed after any working link requiring constant flow output, thus achieving constant flow output for that link. Experimental results show that, compared to traditional designs, tractors using this solution exhibit higher uniformity in sowing and fertilization operations during seeding tests, making it particularly suitable for precision agriculture scenarios and meeting the demands of modern agriculture for efficient and reliable equipment.

[0054] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "several" means at least one, and may include two, three, or more; "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0056] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A multi-way valve for tractors, characterized in that, The tractor multi-way valve includes: Oil inlet and outlet (9), including main oil inlet (7); The priority working link (1) includes a main directional valve (6) and a constant flow valve (21) disposed after the main directional valve (6). The constant flow valve (21) includes an adjustable throttle valve (10) and a pressure compensation valve (14) for stabilizing the pressure difference between the two ends of the adjustable throttle valve (10). The working oil in the main inlet (7) flows through the main directional valve (6) to the constant flow valve (21) after the valve, and is output to the main valve inlet (P1) on the front side of the main directional valve (6) through the throttling output port (11) of the adjustable throttle valve (10).

2. The tractor multi-way valve according to claim 1, characterized in that, The first hydraulic control end of the pressure compensation valve (14) is connected to the oil inlet end of the adjustable throttle valve (10) through the first pilot oil passage, and the second hydraulic control end of the pressure compensation valve (14) is connected to the oil outlet end of the adjustable throttle valve (10) through the second pilot oil passage; wherein, the first pilot oil passage is provided with a first damping (13), and the second pilot oil passage is provided with a second damping (19).

3. The tractor multi-way valve according to claim 1 or 2, characterized in that, The tractor multi-way valve also includes: Several downstream working links (2) are located downstream of the valves of the priority working link (1), and the downstream bypass port (17) of the pressure compensation valve (14) is hydraulically connected to the main valve inlet of several of the downstream working links (2).

4. The tractor multi-way valve according to claim 3, characterized in that, The main directional valve (6) is provided with a main valve oil port (C) that runs through the front and rear. The front end of the main valve oil port (C) is connected to the main oil inlet (7) of the inlet and return oil connection (9). The rear end of the main valve oil port (C) is hydraulically connected to the constant flow valve (21). The main valve oil inlet in the rear working connection (2) is hydraulically connected to the rear end of the main valve oil port (C) at the middle valve position of the main directional valve (6) in the priority working connection (1).

5. The tractor multi-way valve according to claim 4, characterized in that, The main directional valve (6) includes a working valve position and an intermediate valve position. In the working valve position, the rear end of the main valve oil port (C) is hydraulically connected to the constant flow valve (21) and is cut off from the main valve oil port of the rear working link (2). In the intermediate valve position, both the constant flow valve (21) and the main valve oil port of the rear working link (2) are hydraulically connected to the rear end of the main valve oil port (C).

6. The tractor multi-way valve according to claim 4, characterized in that, The tractor multi-way valve also includes: Several prior working links (3) are located in front of the valve of the priority working link (1), and the main valve oil passage of the prior working link (3) is hydraulically connected to the main valve oil passage (C) of the priority working link (1).

7. The tractor multi-way valve according to claim 4, characterized in that, The main directional valve (6) includes: The first intermediate valve position is the O-type neutral position function; The second intermediate valve position is a Y-type intermediate position function.

8. The tractor multi-way valve according to claim 1, characterized in that, The tractor multi-way valve is a plate-type multi-way valve including the inlet / return oil connection (9), several working connections and the tail connection. The inlet / return oil connection (9), several working connections and the tail connection are all modular unit structures and are arranged in sequence along the front and rear directions.

9. A tractor, characterized in that, The tractor includes a tractor multi-way valve according to any one of claims 1 to 8.

10. A hydraulic control method for a tractor, characterized in that, The method includes: Identify the actuators that require constant flow supply and define the working links in the tractor multi-way valve corresponding to the actuators as the priority working links (1). The constant flow valve (21) is arranged after the main directional valve (6) of the priority working link (1). The constant flow valve (21) includes an adjustable throttle valve (10) and a pressure compensation valve (14) for stabilizing the pressure difference between the two ends of the adjustable throttle valve (10). The working oil in the main inlet (7) of the inlet and outlet oil connection (9) of the tractor multi-way valve flows through the main reversing valve (6) to the constant flow valve (21) after the valve. The constant flow hydraulic oil output from the throttling output port (11) of the adjustable throttle valve (10) flows through the main directional valve (6) back to the main valve inlet (P1) on the front side of the main directional valve (6). When the flow rate of the working oil at the main inlet (7) is greater than the constant flow rate of the hydraulic oil output from the throttling outlet (11), the excess flow rate is directed through the bypass port (17) of the pressure compensation valve (14) to the main valve inlet of the rear working link (2) located after the priority working link (1).

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