Hydraulic control system for hybrid power gearbox of tractor

Abstract

The invention discloses a tractor hybrid power gearbox hydraulic control system which comprises an oil supply unit, a clutch hydraulic control unit and a gear shifting hydraulic control unit, and the oil supply unit comprises an oil storage tank and a high-pressure oil pump used for supplying oil to a pressure oil way. The clutch hydraulic control unit comprises a first clutch and a second clutch, the first clutch can be controlled to be connected or disconnected through a first clutch control valve, and the second clutch can be controlled to be connected or disconnected through a second clutch control valve. The gear shifting hydraulic control unit comprises a first synchronizer, a second synchronizer and a third synchronizer. And the first synchronizer or the second synchronizer can be controlled to be switched among different gears through the first synchronous control valve and the second synchronous control valve. And whether the third synchronizer is started or not can be controlled through the third synchronous control valve. By means of the clutch, the technical problems that an existing hybrid power gearbox clutch is stiff in engagement and fixed in gear mode can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural vehicle gearboxes, in particular to a tractor hybrid power gearbox hydraulic control system. Background Art

[0002] As an agricultural production tool, the tractor has a complex and changeable operating environment, requiring the driver to switch gears according to factors such as the type of operation and road conditions. The gearbox switches the speed ratio according to the gear selected by the driver to adapt to changes in load or driving resistance, thereby ensuring the tractor's power, fuel economy and driving comfort.

[0003] The quality of gear shifting depends on two aspects: one is the engagement quality of the clutch during the gear shifting process, and the other is the accurate selection and control of the gear by the synchronizer hydraulic control system. At present, there are three working conditions for tractors using hybrid power: independent engine drive, independent motor drive, and engine and motor hybrid drive. The existing gearbox suitable for hybrid power is not only stiff in clutch engagement, but also rigid in driving mode when switching and coordinating between multiple power sources, with only a few fixed driving modes, especially for the hybrid drive state of the engine and the motor. The gear shifting requirements of the hybrid drive state are different from those of traditional DCT, AMT and other transmissions. It is necessary to control the simultaneous operation of multiple clutches and synchronizers in the gearbox in real time according to the load of the tractor to achieve timely intervention of the motor. Summary of the invention

[0004] The purpose of the present invention is to provide a tractor hybrid power transmission hydraulic control system, which can solve the technical problems of stiff clutch engagement and fixed driving mode of the existing hybrid power transmission.

[0005] In order to achieve the above object, the present invention adopts the following technical solution.

[0006] A tractor hybrid power transmission hydraulic control system comprises an oil supply unit, a clutch hydraulic control unit and a shift hydraulic control unit. The oil supply unit comprises an oil storage tank and a high-pressure oil pump for supplying oil to a pressure oil circuit.

[0007] The clutch hydraulic control unit includes a first clutch for engaging the first / third gear with the engine and a second clutch for engaging the second / fourth gear with the engine. The first clutch is connected to the pressure oil circuit through a first clutch control valve, and the engagement or disconnection of the first clutch can be controlled by the first clutch control valve. The second clutch is connected to the pressure oil circuit through a second clutch control valve, and the engagement or disconnection of the second clutch can be controlled by the second clutch control valve.

[0008] The shift hydraulic control unit includes a first synchronizer for switching the first / third gear, a second synchronizer for switching the second / fourth gear, and a third synchronizer for switching the fifth gear / reverse gear. The fifth gear / reverse gear are both driven by electric motors.

[0009] The first synchronizer and the second synchronizer are both connected to the pressure oil circuit through the first synchronous control valve and the second synchronous control valve. The first synchronous control valve and the second synchronous control valve can control the first synchronizer or the second synchronizer to switch between different gears. A first reversing valve for switching the control object is provided between the synchronizer and the synchronous control valve.

[0010] The third synchronizer is connected to the pressure oil circuit through the third synchronous control valve, and the third synchronous control valve can control whether the third synchronizer is enabled. A second reversing valve is provided between the third synchronizer and the third synchronous control valve for controlling the switching of the third synchronizer between fifth gear and reverse gear.

[0011] Furthermore, the second reversing valve is a hydraulic reversing valve, and the control oil circuit of the second reversing valve is connected to the outlets of the first synchronous control valve and the second synchronous control valve, and is used to switch the second reversing valve to the position of controlling the third synchronizer to engage in reverse gear when the first synchronizer and the second synchronizer are disconnected from the pressure oil circuit.

[0012] Furthermore, the oil supply unit also includes a low-pressure oil pump for lubricating and cooling the gearbox. The high-pressure oil pump is coaxially connected to the low-pressure oil pump. The inlets of the high-pressure oil pump and the low-pressure oil pump are connected to the oil storage tank through a first filter. The outlet of the low-pressure oil pump is connected to the radiator. The outlet of the radiator passes through a second filter and enters the lubricating oil circuit. A pressure limiting valve is provided on the lubricating oil circuit.

[0013] Furthermore, a bypass valve is provided at the second filter.

[0014] Furthermore, a buffer device is provided between the clutch and the clutch control valve for alleviating and absorbing the impact vibration generated when the clutch is engaged.

[0015] Furthermore, the buffer device includes a pressure sensor, an electromagnetic ball valve and an accumulator. The pressure sensor is used to monitor the oil pressure in the clutch reset cylinder. The accumulator is connected to the reset cylinder oil inlet pipeline through the electromagnetic ball valve. The electromagnetic valve can control the hydraulic oil to enter the accumulator or the hydraulic oil to be discharged from the accumulator.

[0016] Furthermore, the high-pressure oil pump is connected to the pressure oil circuit through the third filter, and a relief valve is provided on the pressure oil circuit.

[0017] Furthermore, a bypass valve is provided at the third filter.

[0018] Furthermore, the first clutch control valve, the second clutch control valve, the first synchronous control valve, the second synchronous control valve, the third synchronous control valve, and the first reversing valve are all solenoid valves.

[0019] Furthermore, the first clutch control valve, the second clutch control valve, the first synchronous control valve, the second synchronous control valve, and the third synchronous control valve are all two-position three-way valves, and the first reversing valve is a two-position nine-way valve.

[0020] After adopting the above technical solution, the present invention has the following beneficial effects: 1. The engine part and the motor part of the present invention adopt independent synchronizers. By individually controlling the working states of different synchronizers, the engine drive, motor drive or hybrid drive mode can be flexibly switched, and the drive mode can be flexibly adjusted according to the change of load; 2. The present invention is provided with a buffer device in front of the clutch. By controlling the electromagnetic ball valve, the hydraulic oil is diverted into the accumulator at the initial stage of clutch engagement and released from the accumulator at the rear end of clutch engagement, so as to realize the clutch engagement process of first slow and then fast. At the same time, it can absorb the vibration caused by the large speed difference of the clutch friction plate in the early stage of engagement, so that the clutch is smoothly engaged; 3. The present invention is also provided with a lubrication cooling unit for cooling and actively lubricating the mechanical parts of the gearbox, thereby ensuring the long-term stable operation of the gearbox. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0022] Figure 2 It is a schematic diagram of the state of the first gear of the present invention when working alone.

[0023] Figure 3 It is a schematic diagram of the state when the second gear of the present invention works alone.

[0024] Figure 4 It is a schematic diagram of the state of the third gear of the present invention when working alone.

[0025] Figure 5 It is a schematic diagram of the state of the fourth gear of the present invention when working alone.

[0026] Figure 6 It is a schematic diagram of the state of the fifth gear of the present invention when working alone.

[0027] Figure 7 It is a schematic diagram of the state of the present invention when in reverse gear.

[0028] Figure 8 It is a schematic diagram of the state of the first gear and the fifth gear mixed driving of the present invention.

[0029] Fig. 9It is a schematic diagram of the state of the second gear and the fifth gear mixed drive of the present invention.

[0030] Description of the drawings: 1. Oil supply unit, 111. High-pressure oil pump, 112. Low-pressure oil pump, 12. Oil storage tank, 131. First filter, 132. Second filter, 133. Third filter, 14. Radiator, 15. Pressure limiting valve, 16. Overflow valve, 17. Bypass valve, 2. Clutch hydraulic control unit, 211. First clutch, 212. Second clutch, 221. First clutch control valve, 222. Second clutch control valve, 23. Buffer device, 231. Pressure sensor, 232. Solenoid ball valve, 233. Accumulator, 24. Reset cylinder, 3. Shift hydraulic control unit, 311. First synchronizer, 312. Second synchronizer, 313. Third synchronizer, 321. First synchronization control valve, 322. Second synchronization control valve, 323. Third synchronization control valve, 331. First reversing valve, 332. Second reversing valve. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the features and performances of a tractor hybrid power transmission hydraulic control system of the present invention are further described in detail below in conjunction with the accompanying drawings and embodiments.

[0032] Please see attached Figure 1 A tractor hybrid power transmission hydraulic control system includes an oil supply unit 1, a clutch hydraulic control unit 2 and a shift hydraulic control unit 3.

[0033] The oil supply unit 1 includes an oil storage tank 12 and a high-pressure oil pump 111 for supplying oil to the pressure oil circuit, and also includes a low-pressure oil pump 112 for lubricating and cooling the gearbox. The high-pressure oil pump 111 is a small-flow high-pressure pump, and the low-pressure oil pump 112 is a large-flow low-pressure pump.

[0034] The high-pressure oil pump 111 is coaxially connected to the low-pressure oil pump 112. The inlets of the high-pressure oil pump 111 and the low-pressure oil pump 112 are both connected to the oil storage tank 12 through the first filter 131. The first filter 131 is used for primary filtering of impurities in the oil.

[0035] The high-pressure oil pump 111 is connected to the pressure oil circuit through the third filter 133. The pressure oil circuit is provided with a relief valve 16 to prevent the pressure in the pressure oil circuit from exceeding a limit value.

[0036] The outlet of the low-pressure oil pump 112 is connected to the radiator 14, and the outlet of the radiator 14 is connected to the lubricating oil circuit after passing through the second filter 132. A pressure limiting valve 15 is provided on the lubricating oil circuit to maintain the pressure of the oil in the oil circuit at 0-3 bar.

[0037] The second filter 132 and the third filter 133 are both provided with bypass valves 17 for allowing the oil to flow temporarily through the bypass valves when the filters are blocked, so as to prevent the pressure from exceeding the limit value.

[0038] The clutch hydraulic control unit 2 includes a first clutch 211 for engaging the first / third gear with the engine and a second clutch 212 for engaging the second / fourth gear with the engine. The first clutch 211 and the second clutch 212 are both driven by their respective reset cylinders 24 to achieve engagement and disengagement. When the first clutch 211 is engaged, the driving shaft corresponding to the first / third gear is connected to the engine and rotates with the crankshaft, and when the second clutch 212 is engaged, the driving shaft corresponding to the second / fourth gear is connected to the engine and rotates with the crankshaft.

[0039] The first clutch 211 is connected to the pressure oil circuit through the first clutch control valve 221, and the engagement or disconnection of the first clutch 211 can be controlled by the first clutch control valve 221. The second clutch 212 is connected to the pressure oil circuit through the second clutch control valve 222, and the engagement or disconnection of the second clutch 212 can be controlled by the second clutch control valve 222. The first clutch control valve 221 and the second clutch control valve 222 are both two-position three-way solenoid valves.

[0040] A buffer device 23 is provided between the clutch and the clutch control valve to relieve and absorb the impact vibration generated when the clutch is engaged. The buffer device 23 includes a pressure sensor 231, an electromagnetic ball valve 232 and an accumulator 233. The pressure sensor 231 is used to monitor the oil pressure in the clutch reset cylinder 24. The accumulator 233 is connected to the oil inlet pipeline of the reset cylinder 24 through the electromagnetic ball valve 232. The electromagnetic valve can control the hydraulic oil to enter the accumulator 233 or the hydraulic oil to be discharged from the accumulator 233.

[0041] In the initial stage of clutch engagement, the electromagnetic ball valve 232 is in a state that allows hydraulic oil to enter the accumulator 233. In the initial stage of clutch engagement, the master / slave friction plates in the clutch will generate a large impact during the contact process due to the large speed difference. The impact is transmitted to the accumulator 233 through the reset cylinder 24 via the hydraulic oil. Due to the buffering effect of the accumulator 233, the impact generated by the clutch friction plate engagement can be effectively reduced. When the clutch engagement enters the middle and rear stages, the speed difference between the master / slave friction plates decreases, and the impact generated also decreases accordingly. When the pressure sensor 231 detects that the pressure in the reset cylinder 24 reaches a certain value, the electromagnetic ball valve 232 is controlled to switch to a state that allows hydraulic oil to be discharged from the accumulator 233, accelerating the clutch engagement speed, avoiding excessive sliding time to generate large sliding work, and reducing the service life of the clutch.

[0042] The gear shift hydraulic control unit 3 includes a first synchronizer 311 for switching the first / third gear, a second synchronizer 312 for switching the second / fourth gear, and a third synchronizer 313 for switching the fifth / reverse gear, and the fifth / reverse gear are all driven by a motor. The synchronizer switches the corresponding synchronous gear to circumferentially fix the gear corresponding to the gear position with the corresponding drive shaft, so that the gearbox is engaged in different gear positions.

[0043] The first synchronizer 311 and the second synchronizer 312 are both connected to the pressure oil circuit through the first synchronization control valve 321 and the second synchronization control valve 322. The first synchronization control valve 321 and the second synchronization control valve 322 can control the first synchronizer 311 or the second synchronizer 312 to switch between different gears, and a first reversing valve 331 for switching the control object is provided between the synchronizer and the synchronization control valve. The first synchronization control valve 321 and the second synchronization control valve 322 are both two-position three-way valve solenoid valves, and the first reversing valve 331 is a two-position nine-way valve solenoid valve.

[0044] The third synchronizer 313 is connected to the pressure oil circuit through the third synchronization control valve 323. The third synchronization control valve 323 can control whether the third synchronizer 313 is enabled. A second reversing valve 332 for controlling the third synchronizer 313 to switch between the fifth gear and the reverse gear is provided between the third synchronizer 313 and the third synchronization control valve 323. The third synchronization control valve 323 is a two-position three-way solenoid valve.

[0045] The second reversing valve 332 is a hydraulic reversing valve, and the control oil circuit of the second reversing valve 332 is connected to the outlets of the first synchronous control valve 321 and the second synchronous control valve 322, and is used to switch the second reversing valve 332 to the position of controlling the third synchronizer 313 to engage in reverse gear when the first synchronizer 311 and the second synchronizer 312 are disconnected from the pressure oil circuit.

[0046] In specific implementation, the tractor driver selects the appropriate gear according to the type of operation. Since the first to fourth gears are all driven by the engine, in order to keep the engine in the appropriate power range, the transmission ratios of the first to fourth gears increase successively. Usually, the first and second gears are used in high-load scenarios, and the third and fourth gears are used in medium-load scenarios. The fifth gear and reverse gear are both driven by the motor. The fifth gear is used in light-load scenarios, and the reverse gear is used in scenarios that require reversing. The transmission ratios of the fifth gear and reverse gear are specifically determined according to the motor characteristics and application scenarios.

[0047] Embodiment 1 When the driver selects first gear, Figure 2 shown.

[0048] In the shift hydraulic control unit 3, the first reversing valve 331 is in the left position, the control object is the first synchronizer 311, and the second synchronizer 312 is in the reset state.

[0049] The first synchronous control valve 321 is switched to the left position, and the second synchronous control valve 322 is in the right position. The hydraulic oil in the pressure oil circuit enters the end of the first synchronizer 311 corresponding to the first gear through the first synchronous control valve 321 and the first reversing valve 331, so that the first synchronizer 311 shifts the corresponding synchronous gear to circumferentially fix the first gear gear and the output shaft of the first clutch 211.

[0050] The third synchronization control valve 323 is in the right position, and the third synchronizer 313 is in the reset state.

[0051] In the clutch hydraulic control unit 2, the first clutch control valve 221 is switched to the left position, so that the first clutch 211 is connected to the pressure oil circuit, and the hydraulic oil enters the reset cylinder 24 corresponding to the first clutch 211, driving the first clutch 211 to engage. The second clutch control valve 222 is in the right position, so that the second clutch 212 is in a disengaged state.

[0052] After the first clutch 211 is engaged, the power of the engine drives the first gear to rotate synchronously through the first clutch 211, so that the tractor is driven in the first gear.

[0053] Embodiment 2 When the driver selects second gear, Figure 3 shown.

[0054] In the shift hydraulic control unit 3 , the first reversing valve 331 is switched to the right position, the control object is the second synchronizer 312 , and the first synchronizer 311 is in a reset state.

[0055] The first synchronous control valve 321 is switched to the left position, and the second synchronous control valve 322 is in the right position. The hydraulic oil in the pressure oil circuit enters the end of the second synchronizer 312 corresponding to the second gear through the first synchronous control valve 321 and the first reversing valve 331, so that the second synchronizer 312 shifts the corresponding synchronous gear to circumferentially fix the second gear gear and the output shaft of the second clutch 212.

[0056] The third synchronization control valve 323 is in the right position, and the third synchronizer 313 is in the reset state.

[0057] In the clutch hydraulic control unit 2, the second clutch control valve 222 is switched to the left position, so that the second clutch 212 is connected to the pressure oil circuit, and the hydraulic oil enters the reset cylinder 24 corresponding to the second clutch 212, driving the second clutch 212 to engage. The first clutch control valve 221 is in the right position, so that the first clutch 211 is in a disengaged state.

[0058] After the second clutch 212 is engaged, the power of the engine drives the second gear to rotate synchronously through the second clutch 212, so that the tractor is driven in the second gear.

[0059] Embodiment 3 When the driver selects third gear, Figure 4 shown.

[0060] In the shift hydraulic control unit 3, the first reversing valve 331 is in the left position, the control object is the first synchronizer 311, and the second synchronizer 312 is in the reset state.

[0061] The second synchronous control valve 322 is switched to the left position, and the first synchronous control valve 321 is in the right position. The hydraulic oil in the pressure oil circuit enters the end of the first synchronizer 311 corresponding to the third gear through the second synchronous control valve 322 and the first reversing valve 331, so that the first synchronizer 311 shifts the corresponding synchronous gear, and fixes the third gear gear circumferentially with the output shaft of the first clutch 211.

[0062] The third synchronization control valve 323 is in the right position, and the third synchronizer 313 is in the reset state.

[0063] In the clutch hydraulic control unit 2, the first clutch control valve 221 is switched to the left position, so that the first clutch 211 is connected to the pressure oil circuit, and the hydraulic oil enters the reset cylinder 24 corresponding to the first clutch 211, driving the first clutch 211 to engage. The second clutch control valve 222 is in the right position, so that the second clutch 212 is in a disengaged state.

[0064] After the first clutch 211 is engaged, the power of the engine drives the third gear to rotate synchronously through the first clutch 211, so that the tractor is driven in the third gear.

[0065] Embodiment 4 When the driver selects fourth gear, Figure 5 shown.

[0066] In the shift hydraulic control unit 3 , the first reversing valve 331 is switched to the right position, the control object is the second synchronizer 312 , and the first synchronizer 311 is in a reset state.

[0067] The second synchronous control valve 322 is switched to the left position, and the first synchronous control valve 321 is in the right position. The hydraulic oil in the pressure oil circuit enters the end of the second synchronizer 312 corresponding to the fourth gear through the second synchronous control valve 322 and the first reversing valve 331, so that the second synchronizer 312 shifts the corresponding synchronous gear, and fixes the fourth gear gear and the output shaft of the second clutch 212 circumferentially.

[0068] The third synchronization control valve 323 is in the right position, and the third synchronizer 313 is in the reset state.

[0069] In the clutch hydraulic control unit 2, the second clutch control valve 222 is switched to the left position, so that the second clutch 212 is connected to the pressure oil circuit, and the hydraulic oil enters the reset cylinder 24 corresponding to the second clutch 212, driving the second clutch 212 to engage. The first clutch control valve 221 is in the right position, so that the first clutch 211 is in a disengaged state.

[0070] After the second clutch 212 is engaged, the power of the engine drives the fourth gear to rotate synchronously through the second clutch 212, so that the tractor is driven in the fourth gear.

[0071] Embodiment 5 When the driver selects fifth gear, Figure 6 shown.

[0072] In the shift hydraulic control unit 3, the first reversing valve 331 is in the left position, the control object is the first synchronizer 311, and the second synchronizer 312 is in the reset state.

[0073] The first synchronous control valve 321 and the second synchronous control valve 322 are both switched to the left position, and the hydraulic oil in the pressure oil circuit enters both ends of the first synchronizer 311 through the first synchronous control valve 321 and the second synchronous control valve 322 at the same time. The pressure at both ends of the first synchronizer 311 is balanced and is still in a reset state.

[0074] The second selector valve 332 is controlled by the pressure at the outlet of the first synchronous control valve 321 and the second synchronous control valve 322 to be in the left position, that is, to control the position of the third synchronizer 313 to engage in the fifth gear. When the third synchronous control valve 323 is switched to the left position, the hydraulic oil in the pressure oil circuit enters the end of the third synchronizer 313 corresponding to the fifth gear through the third synchronous control valve 323 and the second selector valve 332, so that the third synchronizer 313 shifts the corresponding synchronous gear, and the fifth gear gear is circumferentially fixed to the output shaft of the motor.

[0075] Since the fifth gear is driven independently by the motor, in the clutch hydraulic control unit 2, the first clutch control valve 221 and the second clutch control valve 222 are both in the right position, so that the first clutch 211 and the second clutch 212 are both in a disengaged state.

[0076] The power of the motor drives the five-speed gear to rotate synchronously, so that the tractor can be driven in five gears. At this time, the engine can be stopped or drive the generator to charge the power battery.

[0077] Embodiment 6 When the driver selects reverse gear, Figure 7 shown.

[0078] In the shift hydraulic control unit 3 , the first synchronous control valve 321 and the second synchronous control valve 322 are both in the right position, and the first synchronizer 311 and the second synchronizer 312 are both in the reset state.

[0079] Since there is no pressure at the outlets of the first synchronous control valve 321 and the second synchronous control valve 322, the second selector valve 332 is in the right position, i.e., the position for controlling the third synchronizer 313 to engage in reverse gear. When the third synchronous control valve 323 is switched to the left position, the hydraulic oil in the pressure oil circuit enters the end of the third synchronizer 313 corresponding to the reverse gear through the third synchronous control valve 323 and the second selector valve 332, so that the third synchronizer 313 shifts the corresponding synchronous gear, and the reverse gear is circumferentially fixed to the output shaft of the motor.

[0080] Since the reverse gear is independently driven by the motor, in the clutch hydraulic control unit 2, the first clutch control valve 221 and the second clutch control valve 222 are both in the right position, so that the first clutch 211 and the second clutch 212 are both in a disengaged state.

[0081] The power of the motor drives the reverse gear to rotate synchronously, so that the tractor can be driven backward in reverse gear. At this time, the engine can be stopped or the generator can be driven to charge the power battery.

[0082] Embodiment 7 Since tractors mostly work on unpaved roads such as fields, the surface conditions are changeable and undulating, and the resistance changes greatly during operation. When the tractor is running in first gear and detects a sudden increase in load, the system automatically activates the hybrid drive mode and calls on the motor and engine to drive simultaneously.

[0083] like Figure 8 As shown, based on the transmission being in the first gear, the second selector valve 332 is controlled by the pressure at the outlet of the first synchronous control valve 321 to be in the left position, that is, the third synchronizer 313 is controlled to be in the fifth gear.

[0084] Switch the third synchronous control valve 323 to the left position, and the hydraulic oil in the pressure oil circuit enters the end of the third synchronizer 313 corresponding to the fifth gear through the third synchronous control valve 323 and the second selection valve 332, so that the third synchronizer 313 shifts the corresponding synchronous gear to fix the fifth gear gear circumferentially with the output shaft of the motor.

[0085] At this time, the power of the motor drives the five-speed gear to rotate synchronously, intervene in the drive of the tractor, provide additional power, and increase the output power of the tractor. Due to the motor's large power range and fast response ability, it can intervene in the drive in time when the tractor load changes suddenly, so that the engine can maintain a stable operating condition and improve fuel economy.

[0086] Embodiment 8 When the tractor is running in second gear and a sudden increase in load is detected, the system automatically activates the hybrid drive mode, calling on the motor and engine to drive simultaneously.

[0087] like Fig. 9 As shown, based on the transmission being in the second gear, the second selector valve 332 is controlled by the pressure at the outlet of the first synchronous control valve 321 to be in the left position, that is, the third synchronizer 313 is controlled to be in the fifth gear.

[0088] Switch the third synchronous control valve 323 to the left position, and the hydraulic oil in the pressure oil circuit enters the end of the third synchronizer 313 corresponding to the fifth gear through the third synchronous control valve 323 and the second selection valve 332, so that the third synchronizer 313 shifts the corresponding synchronous gear to fix the fifth gear gear circumferentially with the output shaft of the motor.

[0089] At this time, the power of the motor drives the five-speed gear to rotate synchronously, intervening in the drive of the tractor, providing additional power and increasing the output power of the tractor.

[0090] Embodiment 9 When the tractor is running in the third to fifth gear and a sudden increase in load is detected, the system prompts the operator to downshift to increase the tractor's traction.

[0091] It should be noted that the gear names in the accompanying drawings are represented by Roman numerals and letters, but based on common sense, it is clear that gear I, gear II, gear III, gear IV, gear V and gear R correspond to gear 1, gear 2, gear 3, gear 4, gear 5 and reverse gear respectively.

[0092] It should be further explained that the parts not described in detail in this scheme are all prior art, and the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the present invention.

Claims

1. A tractor hybrid power transmission hydraulic control system, comprising an oil supply unit (1), a clutch hydraulic control unit (2) and a shift hydraulic control unit (3), characterized in that: The oil supply unit (1) comprises an oil storage tank (12) and a high-pressure oil pump (111) for supplying oil to a pressure oil circuit. The clutch hydraulic control unit (2) comprises a first clutch (211) for engaging the first / third gear with the engine and a second clutch (212) for engaging the second / fourth gear with the engine. The first clutch (211) is connected to the pressure oil circuit via a first clutch control valve (221), and the engagement or disconnection of the first clutch (211) can be controlled via the first clutch control valve (221). The second clutch (212) is connected to the pressure oil circuit via a second clutch control valve (222), and the engagement or disconnection of the second clutch (212) can be controlled via the second clutch control valve (222). The gear shift hydraulic control unit (3) comprises a first synchronizer (311) for switching the first gear / third gear, a second synchronizer (312) for switching the second gear / fourth gear, and a third synchronizer (313) for switching the fifth gear / reverse gear. The fifth gear / reverse gear are both driven by a motor. The first synchronizer (311) and the second synchronizer (312) are both connected to the pressure oil circuit through the first synchronizer control valve (321) and the second synchronizer control valve (322). The first synchronizer control valve (321) and the second synchronizer control valve (322) can control the first synchronizer (311) or the second synchronizer (312) to switch between different gears. A first reversing valve (331) for switching the control object is provided between the synchronizer and the synchronizer control valve. The third synchronizer (313) is connected to the pressure oil circuit via the third synchronizer control valve (323), and whether the third synchronizer (313) is enabled can be controlled via the third synchronizer control valve (323). A second reversing valve (332) for controlling the third synchronizer (313) to switch between fifth gear and reverse gear is provided between the third synchronizer (313) and the third synchronizer control valve (323).

2. A tractor hybrid power transmission hydraulic control system as claimed in claim 1, characterized in that: The second reversing valve (332) is a hydraulic reversing valve. The control oil circuit of the second reversing valve (332) is connected to the outlets of the first synchronous control valve (321) and the second synchronous control valve (322). When the first synchronizer (311) and the second synchronizer (312) are disconnected from the pressure oil circuit, the second reversing valve (332) is switched to a position for controlling the third synchronizer (313) to engage the reverse gear.

3. A tractor hybrid power transmission hydraulic control system as claimed in claim 1, characterized in that: The oil supply unit (1) further comprises a low-pressure oil pump (112) for lubricating and cooling the gearbox; the high-pressure oil pump (111) and the low-pressure oil pump (112) are coaxially connected; the inlets of the high-pressure oil pump (111) and the low-pressure oil pump (112) are both connected to the oil storage tank (12) through a first filter (131); the outlet of the low-pressure oil pump (112) is connected to the radiator (14); the outlet of the radiator (14) passes through a second filter (132) and then enters a lubricating oil circuit; a pressure limiting valve (15) is provided on the lubricating oil circuit.

4. A tractor hybrid power transmission hydraulic control system as claimed in claim 1, characterized in that: A buffer device (23) is provided between the clutch and the clutch control valve for absorbing the impact vibration generated when the clutch is engaged.

5. A tractor hybrid power transmission hydraulic control system as claimed in claim 4, characterized in that: The buffer device (23) comprises a pressure sensor (231), an electromagnetic ball valve (232) and an accumulator (233). The pressure sensor (231) is used to monitor the oil pressure in the clutch reset oil cylinder (24). The accumulator (233) is connected to the oil inlet pipeline of the reset oil cylinder (24) via the electromagnetic ball valve (232). The electromagnetic valve can control the hydraulic oil to enter the accumulator (233) or the hydraulic oil to be discharged from the accumulator (233).

6. A tractor hybrid power transmission hydraulic control system as claimed in claim 1, characterized in that: The high-pressure oil pump (111) is connected to a pressure oil circuit through a third filter (133), and a relief valve (16) is provided on the pressure oil circuit.

7. A tractor hybrid power transmission hydraulic control system as claimed in claim 1, characterized in that: The first clutch control valve (221), the second clutch control valve (222), the first synchronous control valve (321), the second synchronous control valve (322), the third synchronous control valve (323), and the first reversing valve (331) are all solenoid valves.

8. A tractor hybrid power transmission hydraulic control system as claimed in claim 7, characterized in that: The first clutch control valve (221), the second clutch control valve (222), the first synchronous control valve (321), the second synchronous control valve (322), and the third synchronous control valve (323) are all two-position three-way valves, and the first reversing valve (331) is a two-position nine-way valve.

9. A tractor hybrid power transmission hydraulic control system as claimed in claim 3, characterized in that: A bypass valve (17) is provided at the second filter (132).

10. A tractor hybrid power transmission hydraulic control system as claimed in claim 6, characterized in that: A bypass valve (17) is provided at the third filter (133).

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