Gear shifting valve group of tractor chassis

Abstract

The invention relates to a tractor chassis gear shifting valve group which comprises a proportional pressure reducing valve, an electromagnetic clutch valve, a logic valve, an overload valve and a logic valve pressure regulating valve. The logic valve is arranged in a main oil way of the hydraulic system and used for controlling system pressure. The logic valve pressure regulating valve is connected with the logic valve and is used for regulating the working pressure of the logic valve; the proportional pressure reducing valve is arranged on the main oil way and used for controlling the opening and closing states of the gear shifting clutch. The electromagnetic clutch valve is arranged in the main oil way and is used for performing clutch control on the gear shifting system; the overload valve is connected to the lubrication heat dissipation oil way and used for conducting pressure protection on the lubrication heat dissipation system. The stability of pressure and flow change can be improved, and the reliability of the power shifting valve group of the tractor is improved.

Description

Technical Field

[0001] The invention belongs to the field of tractor control, and in particular relates to a tractor chassis shift valve group. Background Art

[0002] The power shift valve group is an indispensable control component for the electrification and intelligent development of tractors. Its main function is to perform power reversing and power shifting through electrical control of the tractor chassis. Compared with the mechanical shift mechanism, it has a compact structure, occupies a small space, and the electrical control operation is flexible and light, with a fast response.

[0003] However, with the iteration of tractor technology, the requirements for system integration and reliability are further improved. Conventional electric proportional shift valve groups are increasingly unable to meet usage needs due to their single function. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, an object of the present invention is to provide a tractor chassis shift valve group.

[0005] The present invention provides a tractor chassis shift valve group, comprising:

[0006] Proportional pressure reducing valve, solenoid clutch valve, logic valve, overload valve and logic valve pressure regulating valve;

[0007] The logic valve is provided in the main oil circuit of the hydraulic system and is used to control the system pressure;

[0008] The logic valve pressure regulating valve is connected to the logic valve and is used to adjust the working pressure of the logic valve;

[0009] The proportional pressure reducing valve is arranged on the main oil line and is used to control the opening and closing state of the shift clutch;

[0010] The electromagnetic clutch valve is arranged in the main oil circuit and is used to perform clutch control on the gear shift system;

[0011] The overload valve is connected to the lubrication and heat dissipation oil circuit and is used for pressure protection of the lubrication and heat dissipation system.

[0012] According to a tractor chassis shift valve group provided by the present invention, a plurality of proportional pressure reducing valves are provided, and the plurality of proportional pressure reducing valves are arranged in parallel on the main oil circuit and correspond one-to-one to the plurality of shift clutches, and are used to respectively control the opening and closing states of the plurality of shift clutches, and the oil inlet ends of the plurality of proportional pressure reducing valves are all connected to the main pressure oil circuit.

[0013] According to a tractor chassis shift valve group provided by the present invention, each proportional pressure reducing valve includes a proportional pressure reducing valve body, a proportional pressure reducing valve spool, a proportional pressure reducing valve spring and a proportional electromagnet. The proportional electromagnet controls the position of the spool through an electric control signal, thereby adjusting the output pressure.

[0014] According to a tractor chassis shift valve group provided by the present invention, the first end of the logic valve is connected to the main pressure oil supply pipeline, the second end of the logic valve is connected to the oil inlet ends of multiple proportional pressure reducing valves, and the third end of the logic valve is connected to the oil return pipeline;

[0015] The logic valve includes a logic valve body, a logic valve main valve core, a logic valve pilot valve core and a logic valve pressure-regulating spring. The logic valve main valve core is arranged in the main oil channel of the logic valve body, and the logic valve pilot valve core is arranged in the pilot oil channel of the logic valve body. The first end of the logic valve pressure-regulating spring acts on the logic valve main valve core, and the second end of the logic valve pressure-regulating spring is connected to the output pressure of the logic valve pressure regulating valve, thereby achieving stable control of the system pressure through pilot control.

[0016] According to a tractor chassis shift valve group provided by the present invention, the first end of the logic valve pressure regulating valve is connected to the control end of the logic valve, and the second end of the logic valve pressure regulating valve is connected to the control pressure oil circuit;

[0017] The logic valve pressure regulating valve is an adjustable pressure reducing valve structure, including a logic valve pressure regulating valve body, a logic valve pressure regulating valve regulating valve core, a logic valve pressure regulating valve regulating spring and a manual adjustment mechanism. The manual adjustment mechanism changes the pressure setting value of the logic valve through the pre-compression amount of the logic valve pressure regulating valve regulating spring to adapt to hydraulic systems with different pressure levels.

[0018] According to the tractor chassis shift valve group provided by the present invention, the electromagnetic clutch valve is arranged in series in the oil circuit between the logic valve and the plurality of proportional pressure reducing valves;

[0019] The electromagnetic clutch valve is a two-position two-way electromagnetic valve structure, including an electromagnetic clutch valve body, an electromagnetic clutch valve valve core, an electromagnetic clutch valve return spring and an electromagnetic clutch valve electromagnet. The electromagnetic clutch valve electromagnet is used to control the on-off state of the oil circuit.

[0020] According to a tractor chassis shift valve group provided by the present invention, the working state of the electromagnetic clutch valve electromagnet includes:

[0021] In the power-off state, when the electromagnetic clutch valve electromagnet is in the power-off state, the electromagnetic clutch valve core is in the closed position under the action of the electromagnetic clutch valve return spring to cut off the oil circuit;

[0022] In the energized state, when the electromagnetic clutch valve electromagnet is energized, the electromagnetic clutch valve spool overcomes the spring force of the electromagnetic clutch valve return spring and moves to the open position to connect the oil circuit, thereby realizing safe clutch control of the entire shifting system.

[0023] According to the tractor chassis shift valve group provided by the present invention, the first end of the overload valve is connected to the oil inlet pipeline of the lubrication and cooling system, and the second end of the overload valve is connected to the oil return pipeline of the lubrication and cooling system;

[0024] The overload valve is a relief valve structure, including an overload valve body, an overload valve main valve core, an overload valve pilot valve and an overload valve pressure regulating spring. When the pressure of the lubrication and cooling system exceeds the set value, the overload valve main valve core opens the overflow channel under the action of pressure, and guides excess oil back to the oil tank to protect the lubrication and cooling system from falling below the overpressure threshold.

[0025] A tractor chassis shift valve group provided by the present invention further includes:

[0026] Multiple pressure test interfaces and multiple sensor installation interfaces;

[0027] The multiple pressure testing interfaces are respectively arranged on the main pressure oil circuit of the logic valve, the oil outlet ends of the multiple proportional pressure reducing valves, the oil inlet end of the overload valve and the oil circuit of the lubrication and cooling system. The multiple sensor installation interfaces are arranged in a one-to-one correspondence with the multiple pressure testing interfaces, and are used to install pressure sensors to realize real-time monitoring of the system pressure.

[0028] According to the present invention, a tractor chassis shift valve group is provided. The tractor chassis shift valve group is suitable for tractor chassis systems of power shift models and CVT continuously variable transmission models.

[0029] The present invention provides a tractor chassis shift valve group, which adopts a technical solution of replacing the traditional overflow valve system working pressure with a logic valve, thereby achieving a significant stabilization of system pressure and flow changes, effectively reducing the heating phenomenon of the hydraulic system during operation, thereby greatly improving the working stability and reliability of the entire shift system, extending the system service life and reducing maintenance costs. The structural design of multiple proportional pressure reducing valves provided by the present invention, which are arranged in parallel and work independently of each other, not only realizes the precise independent control of the clutches of each gear and avoids mutual interference between gears, but also significantly improves the gear shift response speed and gear shift accuracy, so that the tractor can achieve smoother gear switching during operation, reduces the damage to the transmission system caused by gear shift shock, and significantly improves the driving experience of the operator; secondly, the adjustable design of the logic valve pressure regulating valve enables the system to flexibly adapt to different pressure level requirements within the range of 8-25MPa, greatly expanding the scope of application of the product, not only suitable for traditional power shift models, but also perfectly matching CVT continuously variable transmission models, providing greater design freedom and market competitive advantages, while reducing product development costs and inventory pressure; thirdly, the safe clutch control function of the electromagnetic clutch valve provides reliable safety protection for the entire shift system. When the system malfunctions or requires emergency shutdown, it can quickly cut off power transmission in all gears, effectively preventing equipment damage and safety accidents, which is particularly suitable for the development trend of automation and intelligence in modern tractors. In addition, the integrated design of the overload valve and the lubrication and cooling system not only realizes effective pressure protection of the lubrication and cooling system, preventing the system from being damaged by overpressure, but more importantly, the system integration design greatly reduces the demand for independent lubrication and cooling valve groups, significantly reduces the manufacturing cost, installation space and weight of the whole machine, and improves the compactness and economy of the system. Finally, the reserved design of multiple pressure test interfaces and sensor installation interfaces provides great convenience for the debugging and testing of the whole machine and subsequent maintenance. It can support the rapid and accurate monitoring of the pressure status of key parts, timely detect potential problems and perform preventive maintenance, greatly improving the maintainability and fault diagnosis efficiency of the equipment, and reducing equipment downtime and maintenance costs.

[0030] Overall, the high integration of the valve group of the present invention not only realizes the organic combination of multiple functions, but also significantly improves the space utilization efficiency and installation convenience of the system, provides strong support for the compact design of the tractor chassis, meets the urgent needs of modern agricultural machinery for development towards efficiency, intelligence and integration, and creates higher economic benefits and use value for users. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are only for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. Throughout the drawings, the same reference numerals represent the same components. Obviously, the drawings described below are only some of the embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings.

[0032] Figure 1 A schematic structural diagram of a tractor chassis shift valve group provided by an embodiment of the present invention.

[0033] Reference numerals:

[0034] 1. Proportional pressure reducing valve; 2. Electromagnetic clutch valve; 3. Logic valve; 4. Overload valve; 5. Logic valve pressure regulating valve. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are part of the embodiments of the present invention, rather than all of the embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work should fall within the scope of protection of the present invention.

[0036] Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts disclosed in the present invention.

[0037] In the description of the present invention, it should be noted that, unless otherwise expressly specified and limited, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of methods and systems consistent with certain aspects of the present invention, as detailed in the appended claims.

[0039] The following describes embodiments of the present invention with reference to the accompanying drawings.

[0040] like Figure 1 As shown, the present invention provides a tractor chassis shift valve group, Figure 1 In the center, P is the main oil inlet, supplying the system's operating pressure. T is the main oil return port, serving as the system's return port. A1 through A5 are different working oil ports, connected to different shift clutches. A1 and A5 each have two oil ports. A1's two oil ports are bidirectional, controlling both forward and reverse gears. A5, for the highest gear, provides dual control, including additional load monitoring to prevent engine stall or transmission overload caused by excessive loads in high gears. This prevents mechanical damage such as drive shaft breakage, gear clashing, and clutch plate burnout. MA2 through MA4 are conventional measurement points, MP represents the main pressure measurement point, N represents the neutral position in the hydraulic system, and C is the clutch control signal interface.

[0041] A tractor chassis shift valve group of the present invention comprises:

[0042] Proportional pressure reducing valve 1, electromagnetic clutch valve 2, logic valve 3, overload valve 4 and logic valve pressure regulating valve 5; the logic valve 3 is arranged in the main oil circuit of the hydraulic system to control the system pressure; the logic valve pressure regulating valve 5 is connected to the logic valve 3 to adjust the working pressure of the logic valve 3; the proportional pressure reducing valve 1 is arranged in the main oil circuit to control the opening and closing state of the shift clutch; the electromagnetic clutch valve 2 is arranged in the main oil circuit to control the clutch of the shift system; the overload valve 4 is connected to the lubrication and heat dissipation oil circuit to provide pressure protection for the lubrication and heat dissipation system.

[0043] Furthermore, the logic valve of the present invention is arranged in the main oil circuit of the hydraulic system, and has a pressure oil supply port P, an oil return port T and multiple working oil ports. The pressure oil supply port P is connected to the external hydraulic pump oil supply pipeline, and the oil return port T is connected to the oil tank return pipeline. The logic valve is used to control the system working pressure of the entire valve group and replace the function of the traditional overflow valve; the first end of the logic valve pressure regulating valve is connected to the pressure control end of the logic valve, and the second end is connected to the control pressure oil circuit to adjust the working pressure setting value of the logic valve; five proportional pressure reducing valves are arranged in parallel, and each proportional pressure reducing valve has a pressure reducing valve. The oil inlet ends are connected to the working oil ports of the logic valves, and the oil outlet ends are connected to different shift clutch actuators respectively. The return oil ends of each proportional pressure reducing valve are connected to the return oil pipeline T; the electromagnetic clutch valve is arranged in series in the main pressure oil circuit between the logic valve and each proportional pressure reducing valve, and has an electromagnetic control part and a valve body part, which is used to perform overall clutch control of the entire shift system; the overload valve is arranged in the oil circuit of the lubrication and cooling system, and its oil inlet end is connected to the oil supply pipeline of the lubrication and cooling system, and the oil outlet end is connected to the oil return pipeline of the lubrication and cooling system, which is used to provide pressure protection for the lubrication and cooling system.

[0044] Among them, the proportional pressure reducing valve 1 is provided in plurality, and the plurality of proportional pressure reducing valves 1 are arranged in parallel on the main oil circuit and correspond one-to-one with the plurality of shift clutches, and are used to respectively control the opening and closing states of the plurality of shift clutches, and the oil inlet ends of the plurality of proportional pressure reducing valves 1 are connected to the main pressure oil circuit; wherein, each proportional pressure reducing valve 1 includes a proportional pressure reducing valve body, a proportional pressure reducing valve spool, a proportional pressure reducing valve spring and a proportional electromagnet, and the proportional electromagnet controls the valve spool position through an electric control signal, thereby adjusting the output pressure.

[0045] Furthermore, the multiple proportional pressure reducing valves of the present invention adopt a parallel arrangement structure, and each proportional pressure reducing valve establishes a one-to-one control relationship with the corresponding shift clutch through an independent oil circuit, ensuring completely independent control of each gear without mutual interference.

[0046] Specifically, the core operating principle of the proportional pressure reducing valve is based on precise current control of the proportional solenoid. When the controller applies current signals of varying amplitudes to the proportional solenoid, the solenoid generates a corresponding electromagnetic force acting on the proportional pressure reducing valve spool. The spool, balanced by the electromagnetic force and the proportional pressure reducing valve spring force, moves to a specific position, thereby precisely regulating the oil circuit opening and flow rate. The connection between the oil inlet and the main pressure oil circuit ensures that each proportional pressure reducing valve receives a stable pressure oil source. Precise control of the spool position enables linear regulation of the output pressure, which is directly proportional to the input current signal. Compared to traditional on-off control, this proportional control method enables gradual adjustment of the clutch engagement pressure, avoiding sudden pressure shocks and making the shifting process smoother. It also allows the clutch engagement force to be adjusted according to different operating conditions, ensuring reliable power transmission while avoiding energy waste and component wear caused by excessive engagement, significantly improving the service life and fuel economy of the transmission system.

[0047] Among them, the first end of the logic valve 3 is connected to the main pressure oil supply pipeline, the second end of the logic valve 3 is connected to the oil inlet end of multiple proportional pressure reducing valves 1, and the third end of the logic valve 3 is connected to the return oil pipeline; the logic valve 3 includes a logic valve body, a logic valve main valve core, a logic valve pilot valve core and a logic valve pressure regulating spring, the logic valve main valve core is arranged in the main oil channel of the logic valve body, the logic valve pilot valve core is arranged in the pilot oil channel of the logic valve body, the first end of the logic valve pressure regulating spring acts on the logic valve main valve core, and the second end of the logic valve pressure regulating spring is connected to the output pressure of the logic valve pressure regulating valve, so that stable control of the system pressure is achieved through pilot control.

[0048] Furthermore, the logic valve utilizes a pilot control principle, the core of which is to achieve precise and stable control of system pressure through the coordinated cooperation of the logic valve main spool and the logic valve pilot spool. The main pressure supply line delivers high-pressure oil to the logic valve through its first end. The logic valve main spool plays the primary role in pressure regulation in the main oil passage, while the logic valve pilot spool provides precise pressure sensing and control signal transmission in the pilot oil passage. The logic valve pressure-regulating spring, a key component of the entire control system, directly acts on the logic valve main spool at its first end to provide a preset pressure, while its second end is connected to the output pressure of the logic valve pressure regulating valve, forming a closed-loop pressure control circuit. When the system pressure falls below the set value, the logic valve pressure-regulating spring pushes the main spool to open a larger channel area, increasing the oil supply to the proportional pressure reducing valve. When the system pressure rises above the set value, the pilot spool senses the pressure change and adjusts the main spool position, reducing the oil supply channel area.

[0049] The above-mentioned pilot control method has outstanding technical advantages over traditional relief valves: higher pressure control accuracy, smaller pressure fluctuations, faster response speed, less energy loss during pressure regulation, significantly reduced system heat generation, improved energy efficiency and working stability of the entire hydraulic system, and provided a reliable pressure foundation for precise shifting control.

[0050] Among them, the first end of the logic valve pressure regulating valve 5 is connected to the control end of the logic valve 3, and the second end of the logic valve pressure regulating valve 5 is connected to the control pressure oil circuit; the logic valve pressure regulating valve 5 is an adjustable pressure reducing valve structure, including a logic valve pressure regulating valve body, a logic valve pressure regulating valve regulating valve core, a logic valve pressure regulating valve regulating spring and a manual adjustment mechanism. The manual adjustment mechanism changes the pressure setting value of the logic valve 3 through the pre-compression amount of the logic valve pressure regulating valve regulating spring to adapt to hydraulic systems with different pressure levels.

[0051] Furthermore, the logic valve pressure regulating valve is an adjustable pressure reducing valve structure, which can realize flexible adjustment of the system pressure setting value through a manual adjustment mechanism, thereby realizing the combination of mechanical adjustment and hydraulic control.

[0052] Specifically, the manual adjustment mechanism adjusts the output control pressure by varying the pre-compression of the logic valve's pressure regulating spring. When the operator turns the adjustment mechanism, the compression of the logic valve's pressure regulating spring changes, which in turn alters the spring force acting on the logic valve's pressure regulating spool. The pressure signal provided by the control pressure oil circuit balances the spring force. When the spring pre-compression increases, higher oil pressure is required to overcome the spring force and move the spool, thereby increasing the output control pressure; conversely, a decrease in pre-compression reduces the output control pressure. This output control pressure directly acts on the logic valve's pressure control terminal, affecting the equilibrium state of the logic valve's pressure regulating spring and ultimately changing the operating pressure setpoint of the entire system.

[0053] The present invention is based on a logic valve pressure regulating valve, which improves the overall adaptability and can be adjusted within a wide pressure range of 8-25MPa. The same set of valve group products can be adapted to tractor models with different power levels and different working pressure requirements. This not only reduces the manufacturer's product development costs and inventory pressure, but also provides users with greater flexibility in selection. It is particularly suitable for application scenarios of mass production and multi-model sharing.

[0054] Among them, the electromagnetic clutch valve 2 is arranged in series in the oil circuit between the logic valve 3 and multiple proportional pressure reducing valves 1; the electromagnetic clutch valve 2 is a two-position two-way solenoid valve structure, including an electromagnetic clutch valve body, an electromagnetic clutch valve valve core, an electromagnetic clutch valve return spring and an electromagnetic clutch valve electromagnet, and the electromagnetic clutch valve electromagnet is used to control the on-off state of the oil circuit.

[0055] Furthermore, the electromagnetic clutch valve adopts a two-position two-way structural design, which plays a key role as the master switch in the entire gear shift control system. Its series arrangement in the oil circuit between the logic valve and multiple proportional pressure reducing valves ensures unified control capabilities for all gears.

[0056] The working state of the electromagnetic clutch valve electromagnet includes:

[0057] In the power-off state, when the electromagnetic clutch valve electromagnet is in the power-off state, the electromagnetic clutch valve spool is in the closed position under the action of the electromagnetic clutch valve return spring to cut off the oil circuit; in the power-on state, when the electromagnetic clutch valve electromagnet is in the power-on state, the electromagnetic clutch valve spool overcomes the spring force of the electromagnetic clutch valve return spring and moves to the open position to connect the oil circuit, thereby realizing safe clutch control of the entire shifting system.

[0058] Furthermore, the working principle of the electromagnetic clutch valve is based on the on-off state control of the electromagnet. When the electromagnetic clutch valve electromagnet is in the power-off state, the electromagnetic clutch valve spool is maintained in the closed position under the push of the electromagnetic clutch valve return spring. At this time, the oil circuit is completely cut off, and all proportional pressure reducing valves cannot obtain the pressure oil source. The clutches of all gears are in a disengaged state, realizing the safe disconnection of the entire transmission system; when the control system applies current to the electromagnetic clutch valve electromagnet to make it power-on, the electromagnet generates sufficient electromagnetic force to overcome the spring force of the electromagnetic clutch valve return spring, and pushes the electromagnetic clutch valve spool to the open position. After the oil circuit is connected, the pressure oil begins to flow to each proportional pressure reducing valve. At this time, the gear shift control system enters normal working state.

[0059] In abnormal situations such as system failure, emergency shutdown or power outage, the electromagnetic clutch valve will automatically disconnect all power transmission to prevent accidental gear engagement from causing equipment damage or personal injury; at the same time, it provides reliable safety protection for system maintenance and overhaul. Maintenance personnel can ensure that the system is in a completely safe state by disconnecting the electromagnetic clutch valve.

[0060] Among them, the first end of the overload valve 4 is connected to the oil inlet pipeline of the lubrication and cooling system, and the second end of the overload valve 4 is connected to the oil return pipeline of the lubrication and cooling system; the overload valve 4 is a relief valve structure, including an overload valve body, an overload valve main valve core, an overload valve pilot valve and an overload valve pressure regulating spring. When the pressure of the lubrication and cooling system exceeds the set value, the overload valve main valve core opens the overflow channel under the action of pressure, and guides excess oil back to the oil tank to protect the lubrication and cooling system from falling below the overpressure threshold.

[0061] Furthermore, the overload valve of the present invention employs a relief valve design for pressure protection in the lubrication and cooling system. The first end of the overload valve is connected to the lubrication and cooling system's oil inlet line, continuously monitoring the system's actual operating pressure. The second end is connected to the lubrication and cooling system's oil return line, providing a channel for oil discharge in the event of overpressure.

[0062] The main valve core of the overload valve is the core component of pressure sensing. When the pressure of the lubrication and heat dissipation system is within the normal operating range, the preset force of the overload valve pressure regulating spring is greater than the oil pressure force, the main valve core of the overload valve remains closed, and the lubricating oil in the system circulates normally. When the system pressure exceeds the safety threshold due to filter blockage, excessive oil viscosity or other faults, the oil pressure on the main valve core of the overload valve exceeds the preset force of the overload valve pressure regulating spring. Under the coordinated control of the overload valve pilot valve, the main valve core of the overload valve is pushed open, forming an overflow channel from the oil inlet line to the oil return line, and directly directing the excess high-pressure oil back to the oil tank, thereby quickly reducing the system pressure. The overload valve of the present invention not only effectively prevents the lubrication and heat dissipation system from serious faults such as seal damage, pipeline rupture or pump overload caused by overpressure, greatly reduces equipment maintenance costs and downtime, but also ensures the stable operation of the lubrication and heat dissipation system under various working conditions, provides reliable lubrication and heat dissipation guarantees for the engine and transmission system, and extends the service life of the entire machine.

[0063] Among them, also include:

[0064] Multiple pressure test interfaces and multiple sensor installation interfaces;

[0065] The multiple pressure test interfaces are respectively arranged on the main pressure oil circuit of the logic valve 3, the oil outlet ends of the multiple proportional pressure reducing valves 1, the oil inlet end of the overload valve 4 and the oil circuit of the lubrication and cooling system. The multiple sensor installation interfaces are arranged in a one-to-one correspondence with the multiple pressure test interfaces, and are used to install pressure sensors to realize real-time monitoring of the system pressure.

[0066] Furthermore, strategically placed pressure test ports and sensor installation interfaces at key pressure points enable comprehensive monitoring of system status, forming a pressure monitoring network covering the entire valve manifold system. The pressure test ports operate based on a standardized test connection design, allowing maintenance personnel to quickly connect dedicated pressure gauges or test equipment to obtain real-time pressure data at each test point. Comparative analysis of these pressure values ​​allows for rapid identification of system operating status and fault locations.

[0067] The one-to-one correspondence between the sensor installation interface and the pressure test interface enables the system to install permanent pressure sensors for continuous pressure monitoring and data recording. After the pressure sensor is installed, the system can transmit the real-time pressure signal to the controller or monitoring system to realize intelligent functions such as digital display of pressure, historical data recording, abnormal alarm and automatic protection. The setting of the above interface not only greatly simplifies the system debugging process, but also allows engineers to monitor the pressure changes of multiple key points at the same time and quickly optimize the system parameters. It also significantly improves the efficiency of fault diagnosis. Through comparative analysis of pressure data, the faulty components and the cause of the fault can be accurately located. It provides a scientific basis for preventive maintenance. Through long-term pressure data monitoring, the wear trend and replacement time of components can be predicted to avoid economic losses caused by sudden failures.

[0068] The tractor chassis shift valve group of the present invention is suitable for tractor chassis systems of power shift models and CVT continuously variable transmission models.

[0069] The tractor chassis shift valve group provided by the present invention can meet the pressure requirements of different systems. Its scope of application includes power shift (reversing) models, CVT continuously variable transmission models, etc. The valve group of the present invention uses a logic valve instead of a conventional overflow valve to control the working pressure, ensuring that the system pressure and flow changes are more stable and the system heat is reduced. The working pressure of the logic valve can be adjusted to adapt to systems with different pressure levels. For safety reasons, the valve group is equipped with an electromagnetic clutch valve, which can disconnect and reset each gear through electronic control as needed. In view of the increasing system integration, the valve group of the present invention can be connected to lubrication, heat dissipation and other systems without the need for separate lubrication and heat dissipation valves, and is equipped with an overload valve for protecting the lubrication and heat dissipation system, and sufficient pressure testing and sensor installation interfaces are reserved to facilitate the debugging and testing of the entire machine.

[0070] Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or replacements that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be covered by the scope of protection of the present invention.

Claims

1. A tractor chassis shift valve group, characterized in that: include: Proportional pressure reducing valve, solenoid clutch valve, logic valve, overload valve and logic valve pressure regulating valve; The logic valve is provided in the main oil circuit of the hydraulic system and is used to control the system pressure; The logic valve pressure regulating valve is connected to the logic valve and is used to adjust the working pressure of the logic valve; The proportional pressure reducing valve is arranged on the main oil line and is used to control the opening and closing state of the shift clutch; The electromagnetic clutch valve is arranged in the main oil circuit and is used to perform clutch control on the gear shift system; The overload valve is connected to the lubrication and heat dissipation oil circuit and is used for pressure protection of the lubrication and heat dissipation system.

2. The tractor chassis shift valve assembly according to claim 1, characterized in that: There are multiple proportional pressure reducing valves, which are arranged in parallel on the main oil circuit and correspond one-to-one to multiple shift clutches, and are used to control the opening and closing states of multiple shift clutches respectively. The oil inlet ends of the multiple proportional pressure reducing valves are all connected to the main pressure oil circuit.

3. The tractor chassis shift valve assembly according to claim 2, characterized in that: Each proportional pressure reducing valve includes a proportional pressure reducing valve body, a proportional pressure reducing valve core, a proportional pressure reducing valve spring and a proportional electromagnet. The proportional electromagnet controls the position of the valve core through an electric control signal, thereby adjusting the output pressure.

4. The tractor chassis shift valve assembly according to claim 1, characterized in that: The first end of the logic valve is connected to the main pressure oil supply pipeline, the second end of the logic valve is connected to the oil inlet ends of multiple proportional pressure reducing valves, and the third end of the logic valve is connected to the oil return pipeline; The logic valve includes a logic valve body, a logic valve main valve core, a logic valve pilot valve core and a logic valve pressure-regulating spring. The logic valve main valve core is arranged in the main oil channel of the logic valve body, and the logic valve pilot valve core is arranged in the pilot oil channel of the logic valve body. The first end of the logic valve pressure-regulating spring acts on the logic valve main valve core, and the second end of the logic valve pressure-regulating spring is connected to the output pressure of the logic valve pressure regulating valve, thereby achieving stable control of the system pressure through pilot control.

5. The tractor chassis shift valve assembly according to claim 1, characterized in that: The first end of the logic valve pressure regulating valve is connected to the control end of the logic valve, and the second end of the logic valve pressure regulating valve is connected to the control pressure oil circuit; The logic valve pressure regulating valve is an adjustable pressure reducing valve structure, including a logic valve pressure regulating valve body, a logic valve pressure regulating valve regulating valve core, a logic valve pressure regulating valve regulating spring and a manual adjustment mechanism. The manual adjustment mechanism changes the pressure setting value of the logic valve through the pre-compression amount of the logic valve pressure regulating valve regulating spring to adapt to hydraulic systems with different pressure levels.

6. The tractor chassis shift valve assembly according to claim 1, characterized in that: The electromagnetic clutch valve is arranged in series in the oil circuit between the logic valve and a plurality of proportional pressure reducing valves; The electromagnetic clutch valve is a two-position two-way electromagnetic valve structure, including an electromagnetic clutch valve body, an electromagnetic clutch valve valve core, an electromagnetic clutch valve return spring and an electromagnetic clutch valve electromagnet. The electromagnetic clutch valve electromagnet is used to control the on-off state of the oil circuit.

7. The tractor chassis shift valve assembly according to claim 6, characterized in that: The working state of the electromagnetic clutch valve electromagnet includes: In the power-off state, when the electromagnetic clutch valve electromagnet is in the power-off state, the electromagnetic clutch valve core is in the closed position under the action of the electromagnetic clutch valve return spring to cut off the oil circuit; In the energized state, when the electromagnetic clutch valve electromagnet is energized, the electromagnetic clutch valve spool overcomes the spring force of the electromagnetic clutch valve return spring and moves to the open position to connect the oil circuit, thereby realizing safe clutch control of the entire shifting system.

8. The tractor chassis shift valve assembly according to claim 1, characterized in that: The first end of the overload valve is connected to the oil inlet pipeline of the lubrication and cooling system, and the second end of the overload valve is connected to the oil return pipeline of the lubrication and cooling system; The overload valve is a relief valve structure, including an overload valve body, an overload valve main valve core, an overload valve pilot valve and an overload valve pressure regulating spring. When the pressure of the lubrication and cooling system exceeds the set value, the overload valve main valve core opens the overflow channel under the action of pressure, and guides excess oil back to the oil tank to protect the lubrication and cooling system from falling below the overpressure threshold.

9. The tractor chassis shift valve assembly according to claim 1, characterized in that: Also includes: Multiple pressure test interfaces and multiple sensor installation interfaces; The multiple pressure testing interfaces are respectively arranged on the main pressure oil circuit of the logic valve, the oil outlet ends of the multiple proportional pressure reducing valves, the oil inlet end of the overload valve and the oil circuit of the lubrication and cooling system. The multiple sensor installation interfaces are arranged in a one-to-one correspondence with the multiple pressure testing interfaces, and are used to install pressure sensors to realize real-time monitoring of the system pressure.

10. The tractor chassis shift valve assembly according to claim 1, characterized in that: The tractor chassis shift valve group is suitable for tractor chassis systems of power shift models and CVT continuously variable transmission models.

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