Electro-hydraulic control systems for automatic transmissions, agricultural machinery

Abstract

The application discloses an electro-hydraulic control system of an automatic gear shifting gearbox and agricultural machinery. The electro-hydraulic control system controls the working state of a hydraulic control valve group through a controller to drive a multi-point positioning gear shifting hydraulic cylinder to move and position between at least five points, thereby driving a gear shifting gear box to cyclically shift at least three gears. The application shortens the gear shifting time, reduces the gear shifting operation difficulty, and realizes the cyclic shifting of three gears or more through a double-rod hydraulic cylinder, which meets the multi-gear shifting function requirement, does not increase the space volume of the gearbox and the gear shifting failure rate, is beneficial to the miniaturization design of the automatic gear shifting gearbox, and improves the working reliability of the automatic gear shifting gearbox.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gearbox shifting of agricultural machinery, in particular, to an electro-hydraulic control system of an automatic shifting gearbox, and in addition, to an agricultural machinery employing the electro-hydraulic control system. BACKGROUND

[0002] In agricultural machinery, with the centralized management of land, farmers have increasingly high requirements for the automation level of agricultural machinery, and the automatic shifting technology of the gearbox is gradually replacing the traditional hand lever shifting. The traditional hand lever shifting, i.e. the operator operates the clutch structure while manually engaging and disengaging the gear, undoubtedly increases the operation difficulty of the operator and the crop harvesting time, especially for the land that needs to frequently turn around and shift gears, the automatic shifting technology greatly improves the crop harvesting efficiency. However, the current automatic shifting gearbox usually adopts a single hydraulic cylinder for shifting, which can only realize the switching of high and low gears, and if the switching of three gears or more gears is to be realized, the number of hydraulic cylinders needs to be increased, which increases the space volume of the gearbox and the shifting failure rate. For example, patent application CN111720536A discloses a tractor electro-hydraulic control shifting mechanism, which comprises a driving cylinder group, a shifting handle, a hydraulic control system, a shift fork shaft, and a shifting fork. The hydraulic control system controls the oil supply and oil cut of the closed working chamber to realize the reciprocating motion of the driving cylinder group piston and piston rod. The oil cylinder output end transmits power to the shift fork shaft to realize the follow-up of the shift fork, thereby realizing the engagement and separation of the mechanical gear. The advantage is that it adopts button operation, valve body control and hydraulic drive, the transmission route is clear, the structure is compact, and it can be used as an independent module for operating the mechanical shifting gearbox. However, it needs to use multiple hydraulic cylinders to realize the switching of three gears or more gears, which increases the overall volume of the gearbox and has a high shifting failure rate. SUMMARY

[0003] The present application provides an electro-hydraulic control system of an automatic shifting gearbox and an agricultural machinery, to solve the technical problems of large volume of the gearbox and high shifting failure rate when the current automatic shifting gearbox of the agricultural machinery adopts multiple hydraulic cylinders to realize the switching of three gears or more gears.

[0004] According to one aspect of the present invention, an electro-hydraulic control system of an automatic shifting transmission is provided, comprising a speed gearbox, a multi-point positioning shift hydraulic cylinder, a shift fork linkage mechanism, a hydraulic control valve group and a controller, wherein the speed gearbox is driven and connected to a hydraulic motor for transmitting power, the piston rod of the multi-point positioning shift hydraulic cylinder is connected to the speed gearbox through the shift fork linkage mechanism, and is used to drive the speed gearbox to perform cyclic switching of at least three gears, the hydraulic control valve group is respectively connected to an external oil source and the multi-point positioning shift hydraulic cylinder, and is used to provide pressurized oil to the multi-point positioning shift hydraulic cylinder, the hydraulic control valve group is electrically connected to the controller, and the controller drives the multi-point positioning shift hydraulic cylinder to move and position between at least five points by controlling the working state of the hydraulic control valve group, thereby driving the speed gearbox to perform cyclic switching of at least three gears.

[0005] Furthermore, the multi-point positioning shift hydraulic cylinder includes an external cylinder body, an intermediate transition cylinder, a double-outlet piston rod, a piston and an end cover. The intermediate transition cylinder is arranged in the external cylinder body, and the end covers are arranged at both ends of the external cylinder body for fixing the intermediate transition cylinder. The double-outlet piston rod is installed in the intermediate transition cylinder and both ends extend out of the end cover. One end of the double-outlet piston rod is connected to the shift fork linkage mechanism. The piston is located in the intermediate transition cylinder and is fixedly installed on the double-outlet piston rod. The external cylinder body is provided with a plurality of end covers. At least five oil inlets and outlets, at least five annular grooves are provided on the intermediate transition cylinder, each oil inlet and outlet is connected to a corresponding annular groove, and each annular groove is connected to the inner cavity of the intermediate transition cylinder through at least one group of oil holes, the oil inlets and outlets on the external cylinder body are connected to the hydraulic control valve group, and the opening and closing of each oil inlet and outlet is controlled by the hydraulic control valve group, and the controller controls the working state of the hydraulic control valve group to select any two oil inlets and outlets as working oil ports to drive the double-outlet piston rod to move and position between at least five points.

[0006] Furthermore, the outer cylinder body is provided with a first oil inlet and outlet, a second oil inlet and outlet, a third oil inlet and outlet, a fourth oil inlet and outlet, and a fifth oil inlet and outlet in sequence from left to right, and the intermediate transition cylinder is provided with a first annular groove, a second annular groove, a third annular groove, a fourth annular groove, and a fifth annular groove in sequence from left to right, and the five oil inlets and outlets are connected to the five annular grooves in a one-to-one correspondence;

[0007] When the piston moves to the position of the first annular groove, the transmission gear box is in low gear, when the piston moves to the position of the second annular groove, the transmission gear box switches to the first neutral gear, when the piston moves to the position of the third annular groove, the transmission gear box switches to the middle gear, when the piston moves to the position of the fourth annular groove, the transmission gear box switches to the second neutral gear, and when the piston moves to the position of the fifth annular groove, the transmission gear box switches to the high gear.

[0008] Further, the middle part of the piston is a guide ring, and a first sealing ring and a second sealing ring are arranged on the two sides of the guide ring, respectively, the first annular groove and the fifth annular groove are communicated with the inner cavity of the intermediate transition cylinder through a group of oil holes, the second annular groove, the third annular groove and the fourth annular groove are communicated with the inner cavity of the intermediate transition cylinder through two groups of oil holes, respectively, the two groups of oil holes include a first group of oil holes and a second group of oil holes arranged in sequence from left to right, and the spacing between the two groups of oil holes is the same as the spacing between the two sealing rings, during the movement of the double-out piston rod from left to right, when the second sealing ring moves to the position of the first group of oil holes, the double-out piston rod starts to decelerate, and when the second sealing ring moves to the position of the second group of oil holes, the right cavity is in a dead state, and the double-out piston rod stops moving to realize positioning; during the movement of the double-out piston rod from right to left, when the first sealing ring moves to the position of the second group of oil holes, the double-out piston rod starts to decelerate, and when the first sealing ring moves to the position of the first group of oil holes, the left cavity is in a dead state, and the double-out piston rod stops moving to realize positioning.

[0009] Further, the hydraulic control valve group includes a first electromagnetic valve, a second electromagnetic valve, a third electromagnetic valve, a fourth electromagnetic valve, a fifth electromagnetic valve, a sixth electromagnetic valve and a seventh electromagnetic valve, the first electromagnetic valve is connected with an external oil source and a first inlet and outlet oil port, respectively, the seventh electromagnetic valve is connected with an external oil source and a fifth inlet and outlet oil port, respectively, the second electromagnetic valve, the third electromagnetic valve, the fourth electromagnetic valve, the fifth electromagnetic valve and the sixth electromagnetic valve are connected with the first inlet and outlet oil port, the second inlet and outlet oil port, the third inlet and outlet oil port, the fourth inlet and outlet oil port and the fifth inlet and outlet oil port, respectively, and the second electromagnetic valve, the third electromagnetic valve, the fourth electromagnetic valve, the fifth electromagnetic valve and the sixth electromagnetic valve are connected to an external oil tank, the seven electromagnetic valves are electrically connected with a controller, the controller controls the opening and closing of the seven electromagnetic valves to control the extension and retraction of the multi-point positioning gear shifting hydraulic cylinder and the distance of the extension and retraction, so as to control the movement and positioning of the multi-point positioning gear shifting hydraulic cylinder between the five points, thereby driving the transmission gear box to cycle between the low, middle and high gears.

[0010] Further, in the initial state, all solenoid valves are de-energized, the piston is at the leftmost end, and the transmission gear box is in low gear; when the first and third solenoid valves are energized at the same time, the piston moves to the position of the second annular groove and is positioned, and the transmission gear box is switched from low gear to the first neutral gear; when the first and fourth solenoid valves are energized at the same time, the piston moves to the position of the third annular groove and is positioned, and the transmission gear box is switched from the first neutral gear to the middle gear; when the first and fifth solenoid valves are energized at the same time, the piston moves to the position of the fourth annular groove and is positioned, and the transmission gear box is switched from the middle gear to the second neutral gear; when the first and sixth solenoid valves are energized at the same time, the piston moves to the rightmost end, and the transmission gear box is switched from the second neutral gear to the high gear.

[0011] Further, a gear detection block is mounted on the end of the double-out piston rod away from the shift fork linkage mechanism, a sensor mounting plate is mounted on the outer cylinder, five gear detection sensors are arranged on the sensor mounting plate in intervals, and the gear detection sensors are electrically connected to the controller. During the movement of the double-out piston rod, when the corresponding gear detection sensor detects the gear detection block, the controller controls all solenoid valves to be de-energized and stops supplying oil to the multi-point positioning shift hydraulic cylinder.

[0012] Further, the hydraulic control valve group further comprises a one-way valve, a pressure relief overflow valve, and an overflow valve, the one-way valve and the pressure relief overflow valve are sequentially arranged on the oil supply path in the oil supply direction, and the overflow valve is arranged between the oil supply path and the oil return path.

[0013] Further, the transmission gear box comprises a motor input shaft, an output shaft, a shift fork shaft, a shift fork rocker, a low gear, a middle gear, a high gear, a low meshing gear, a shift fork gear, a high meshing gear, and a positioning check bead, the motor input shaft is drivingly connected with the hydraulic motor, the low gear, the middle gear, and the high gear are fixedly connected with the motor input shaft, the low meshing gear and the high meshing gear are bearing-connected with the output shaft and are meshed with the low gear and the high gear respectively, the shift fork gear is meshed with and slidingly connected with the output shaft, the shift fork rocker is fixedly connected with the shift fork shaft and the shift fork gear, the shift fork shaft is fixedly connected with the shift fork linkage mechanism, the shift fork gear is driven to slide leftward and rightward by the shift fork linkage mechanism, so that the gear shifting action of the transmission gear box can be realized, at least five clamping grooves are arranged on the shift fork shaft, and the positioning check bead is used for clamping into the corresponding clamping groove after the gear shifting is successful, so as to position the shift fork shaft.

[0014] When the shift fork gear slides to the left end and engages with the low gear, the transmission gear box is in low gear; when the shift fork gear slides to engage with the middle gear, the transmission gear box is in middle gear; when the shift fork gear slides to engage with the high gear, the transmission gear box is in high gear; when the shift fork gear slides to the position between the low gear and the middle gear, the transmission gear box is in first neutral gear; when the shift fork gear slides to the position between the middle gear and the high gear, the transmission gear box is in second neutral gear.

[0015] In addition, the present application also provides an agricultural machine using the electro-hydraulic control system of the automatic shift transmission box.

[0016] The present application has the following effects:

[0017] The electro-hydraulic control system of the automatic shift transmission box of the present application controls the working state of the hydraulic control valve group through the controller to drive the multi-point positioning shift hydraulic cylinder to move and position between at least five points, thereby driving the transmission gear box to cyclically switch between at least three gears, shortening the shift time and reducing the shift operation difficulty, and only one double-rod hydraulic cylinder can realize the cyclic switching of three gears and above, while meeting the functional requirements of multi-gear switching, without increasing the space volume of the transmission box and the shift failure rate, which is conducive to the miniaturization design of the automatic shift transmission box and improves the working reliability of the automatic shift transmission box.

[0018] In addition, the agricultural machine of the present application also has the above advantages.

[0019] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, illustrate the preferred embodiments of the application and assist in the explanation of the application. In the drawings:

[0021] Figure 1 is a schematic diagram of the electro-hydraulic control system of the automatic shift transmission box of the preferred embodiment of the present application.

[0022] Figure 2 is a structural schematic diagram of the multi-point positioning shift hydraulic cylinder of the preferred embodiment of the present application.

[0023] Figure 3 is a structural schematic diagram of the multi-point positioning shift hydraulic cylinder in the first neutral gear of the preferred embodiment of the present application.

[0024] Figure 4is Figure 3 An enlarged schematic view of the middle A.

[0025] Figure 5 A hydraulic principle schematic view of the hydraulic control valve group of the preferred embodiment of the present application.

[0026] Figure 6 An internal transmission schematic view of the transmission gear box of the preferred embodiment of the present application.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 1. Transmission gear box; 2. Multi-point positioning shift hydraulic cylinder; 3. Shift fork linkage mechanism; 4. Hydraulic control valve group; 100. Hydraulic motor; 11. Motor input shaft; 12. Output shaft; 13. Shift fork shaft; 131. Clamping groove; 14. Fork rocker; 15. Low gear; 16. Middle gear; 17. High gear; 18. Low gear engaging gear; 19. Shift fork gear; 110. High gear engaging gear; 111. Positioning clamping bead; 21. Outer cylinder; 22. Intermediate transition cylinder; 23. Double-outlet piston rod; 24. Piston; 25. End cover; 26. Sealing element; 27. Sensor mounting plate; 28. Gear detection sensor; 211. First inlet and outlet port; 212. Second inlet and outlet port; 213. Third inlet and outlet port; 214. Fourth inlet and outlet port; 215. Fifth inlet and outlet port; 216. First group of oil holes; 217. Second group of oil holes; 221. First annular groove; 222. Second annular groove; 223. Third annular groove; 224. Fourth annular groove; 225. Fifth annular groove; 241. Guide ring; 242. First sealing ring; 243. Second sealing ring; 231. Gear detection block; 281. Low gear detection sensor; 282. First neutral gear detection sensor; 283. Middle gear detection sensor; 284. Second neutral gear detection sensor; 285. High gear detection sensor; 41. First electromagnetic valve; 42. Second electromagnetic valve; 43. Third electromagnetic valve; 44. Fourth electromagnetic valve; 45. Fifth electromagnetic valve; 46. Sixth electromagnetic valve; 47. Seventh electromagnetic valve; 48. Check valve; 49. Pressure relief overflow valve; 410. Overflow valve. DETAILED DESCRIPTION

[0029] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the following.

[0030] It can be understood that, as Figure 1As shown, the preferred embodiment of the present application provides an electro-hydraulic control system of an automatic transmission gearbox for controlling the automatic transmission gearbox to perform gear shifting, which comprises a transmission gearbox 1, a multi-point positioning gear shifting hydraulic cylinder 2, a gear shifting fork linkage mechanism 3, a hydraulic control valve group 4 and a controller, the transmission gearbox 1 is drivingly connected with a hydraulic motor 100 for power transmission, the piston rod of the multi-point positioning gear shifting hydraulic cylinder 2 is connected with the transmission gearbox 1 through the gear shifting fork linkage mechanism 3 for driving the transmission gearbox 1 to cyclically switch at least three gears, the hydraulic control valve group 4 is connected with an external oil source and the multi-point positioning gear shifting hydraulic cylinder 2 respectively for providing pressure oil to the multi-point positioning gear shifting hydraulic cylinder 2. The hydraulic control valve group 4 is electrically connected with the controller, the controller controls the working state of the hydraulic control valve group 4 to drive the multi-point positioning gear shifting hydraulic cylinder 2 to move and position between at least five points, thereby driving the transmission gearbox 1 to cyclically switch at least three gears. Wherein, the gear shifting fork linkage mechanism 3 can adopt the structure forms of connecting plate, connecting rod, multi-link mechanism, etc. In addition, the hydraulic control valve group 4 is specifically installed on the cylinder body of the multi-point positioning gear shifting hydraulic cylinder 2 and is fixed by bolt connection, the multi-point positioning gear shifting hydraulic cylinder 2 is installed on the gearbox body of the transmission gearbox 1, and the gear shifting fork linkage mechanism 3 is installed on the piston rod of the multi-point positioning gear shifting hydraulic cylinder 2 and is connected with the fork extension shaft of the transmission gearbox 1, so that synchronous movement of the piston rod and the fork extension shaft of the transmission gearbox 1 can be realized.

[0031] It can be understood that the electro-hydraulic control system of the automatic transmission gearbox of the embodiment controls the working state of the hydraulic control valve group 4 by the controller to drive the multi-point positioning gear shifting hydraulic cylinder 2 to move and position between at least five points, thereby driving the transmission gearbox 1 to cyclically switch at least three gears, which shortens the gear shifting time and reduces the gear shifting operation difficulty, and only one double-rod hydraulic cylinder can realize the cyclic switching of three gears and more gears, which meets the functional requirement of multi-gear switching while not increasing the space volume of the transmission gearbox and the gear shifting failure rate, is beneficial to realizing the miniaturization design of the automatic transmission gearbox and improves the working reliability of the automatic transmission gearbox.

[0032] Wherein, as Figures 2 to 4As shown, the multi-point positioning gear shift hydraulic cylinder 2 comprises an outer cylinder 21, an intermediate transition cylinder 22 arranged in the outer cylinder 21, a double-out piston rod 23, a piston 24 and end covers 25 arranged at both ends of the outer cylinder 21 for fixing the intermediate transition cylinder 22 and preventing the intermediate transition cylinder 22 from moving left and right in the outer cylinder 21 to affect the gear shift success rate. The double-out piston rod 23 is installed in the intermediate transition cylinder 22 and extends out of the end covers 25 at both ends, one end of the double-out piston rod 23 is connected with the gear shift fork linkage mechanism 3, and through the left and right reciprocating movement of the double-out piston rod 23, the gear shift fork linkage mechanism 3 can be driven to move left and right, thereby realizing the gear shift action of the transmission gearbox 1. The piston 24 is located in the intermediate transition cylinder 22 and is fixedly installed on the double-out piston rod 23, specifically at the middle part of the double-out piston rod 23. At least five inlet and outlet oil ports are formed on the outer cylinder 21, at least five annular grooves are formed on the intermediate transition cylinder 22, each inlet and outlet oil port is in communication with one annular groove, and each annular groove is in communication with the inner cavity of the intermediate transition cylinder 22 through at least one group of oil holes. The inlet and outlet oil ports on the outer cylinder 21 are connected with the hydraulic control valve group 4, the opening and closing of each inlet and outlet oil port is controlled through the hydraulic control valve group 4, and the controller controls the working state of the hydraulic control valve group 4 to select any two inlet and outlet oil ports as working oil ports and the remaining inlet and outlet oil ports are closed, so as to drive the double-out piston rod 23 to move and position between at least five points.

[0033] It can be understood that the multi-point positioning gear shift hydraulic cylinder 2 of the embodiment can realize the gear shift action of the transmission gearbox 1 through the following steps: at least five inlet and outlet oil ports are formed on the outer cylinder 21, at least five annular grooves are formed on the intermediate transition cylinder 22, each inlet and outlet oil port is in communication with one annular groove, and each annular groove is in communication with the inner cavity of the intermediate transition cylinder 22 through at least one group of oil holes, any two inlet and outlet oil ports are selected as working oil ports and the remaining inlet and outlet oil ports are closed, the double-out piston rod 23 is driven to reciprocate in the intermediate transition cylinder 22 by hydraulic oil, the gear shift fork linkage mechanism 3 is driven to move left and right, and the gear shift action of the transmission gearbox 1 is realized. Through one double-out rod hydraulic cylinder, three or more gear positions can be cyclically switched, the space volume of the transmission gearbox and the gear shift failure rate are not increased while meeting the multi-gear switching function requirement, which is conducive to realizing the miniaturization design of the automatic gear shift transmission gearbox and improving the working reliability of the automatic gear shift transmission gearbox.

[0034] Optionally, the end cover 25 is further provided with a sealing element 26 for sealing. Specifically, the sealing element 26 comprises a static sealing ring, a dynamic sealing ring and a dustproof ring, wherein the static sealing ring and the dynamic sealing ring are used to prevent the hydraulic oil from leaking, and the dustproof ring is used to prevent external dust from entering the hydraulic cylinder. In addition, the intermediate transition cylinder barrel 22 is provided with a sealing ring between two adjacent annular grooves to prevent oil from leaking between the annular grooves.

[0035] Specifically, the outer cylinder body 21 is sequentially provided with a first oil inlet and outlet 211, a second oil inlet and outlet 212, a third oil inlet and outlet 213, a fourth oil inlet and outlet 214 and a fifth oil inlet and outlet 215 from left to right, and the intermediate transition cylinder barrel 22 is sequentially provided with a first annular groove 221, a second annular groove 222, a third annular groove 223, a fourth annular groove 224 and a fifth annular groove 225 from left to right, and the five oil inlets and outlets are in one-to-one correspondence with the five annular grooves, i.e. the first oil inlet and outlet 211 communicates with the first annular groove 221, the second oil inlet and outlet 212 communicates with the second annular groove 222, the third oil inlet and outlet 213 communicates with the third annular groove 223, the fourth oil inlet and outlet 214 communicates with the fourth annular groove 224, and the fifth oil inlet and outlet 215 communicates with the fifth annular groove 225. When the piston 24 moves to the position of the first annular groove 221, the transmission gear box 1 is in low gear, when the piston 24 moves to the position of the second annular groove 222, the transmission gear box 1 is switched to the first neutral gear, when the piston 24 moves to the position of the third annular groove 223, the transmission gear box 1 is switched to the middle gear, when the piston 24 moves to the position of the fourth annular groove 224, the transmission gear box 1 is switched to the second neutral gear, and when the piston 24 moves to the position of the fifth annular groove 225, the transmission gear box 1 is switched to high gear, so that the low, middle and high gears can be switched in cycles, and the adjacent two driving gears are smoothly transited through the neutral gear, improving the reliability of gear shifting operation. Of course, in other embodiments, the number of oil inlets and outlets and annular grooves can be increased correspondingly to realize the cycle switching of four gears, five gears, six gears or even seven gears.

[0036] In addition, the middle part of the piston 24 is a guide ring 241 for supporting the double-out piston rod 23 and ensuring coaxiality of the double-out piston rod 23 and the intermediate transition cylinder 22. The two sides of the guide ring 241 are respectively provided with a first sealing ring 242 and a second sealing ring 243 for sealing positioning. The first annular groove 221 and the fifth annular groove 225 are communicated with the inner cavity of the intermediate transition cylinder 22 through a group of oil holes. The second annular groove 222, the third annular groove 223 and the fourth annular groove 224 are respectively communicated with the inner cavity of the intermediate transition cylinder 22 through two groups of oil holes. The two groups of oil holes include a first group of oil holes 216 and a second group of oil holes 217 arranged from left to right, and the spacing between the two groups of oil holes is the same as the spacing between the two sealing rings. Each group of oil holes includes eight symmetrical small oil holes, which can ensure oil passing capacity and prevent cutting damage to the sealing ring when the piston 24 moves left and right. During the movement of the double-out piston rod 23 from left to right, when the second sealing ring 243 moves to the position of the first group of oil holes 216, the double-out piston rod 23 starts to decelerate. When the second sealing ring 243 moves to the position of the second group of oil holes 217, the right cavity is in a dead state, and the double-out piston rod 23 stops moving to achieve positioning. During the movement of the double-out piston rod 23 from right to left, when the first sealing ring 242 moves to the position of the second group of oil holes 217, the double-out piston rod 23 starts to decelerate. When the first sealing ring 242 moves to the position of the first group of oil holes 216, the left cavity is in a dead state, and the double-out piston rod 23 stops moving to achieve positioning.

[0037] It can be understood that, by arranging two groups of oil holes in the intermediate three annular grooves and communicating with the inner cavity of the intermediate transition cylinder 22, and arranging two sealing rings on the piston 24, and the spacing between the two sealing rings is the same as the spacing between the two groups of oil holes, the piston 24 can be accurately positioned at the position corresponding to the two sealing rings and the two groups of oil holes when the gear position is switched from low to high and from high to low, realizing multi-point positioning gear shifting function and further improving the gear shifting success rate.

[0038] It can be understood that, as Figure 5As shown, the hydraulic control valve group 4 includes a first solenoid valve 41, a second solenoid valve 42, a third solenoid valve 43, a fourth solenoid valve 44, a fifth solenoid valve 45, a sixth solenoid valve 46, and a seventh solenoid valve 47, the first solenoid valve 41 is connected with an external oil source and the first in-out oil port 211 respectively, the seventh solenoid valve 47 is connected with an external oil source and the fifth in-out oil port 215 respectively, the second solenoid valve 42, the third solenoid valve 43, the fourth solenoid valve 44, the fifth solenoid valve 45, and the sixth solenoid valve 46 are connected with the first in-out oil port 211, the second in-out oil port 212, the third in-out oil port 213, the fourth in-out oil port 214, and the fifth in-out oil port 215 respectively, and the second solenoid valve 42, the third solenoid valve 43, the fourth solenoid valve 44, the fifth solenoid valve 45, and the sixth solenoid valve 46 are all connected to an external oil tank. It can be understood that the first in-out oil port 211 and the fifth in-out oil port 215 can be used as an oil inlet port or an oil return port, while the second in-out oil port 212, the third in-out oil port 213, and the fourth in-out oil port 214 can only be used as an oil return port. When the piston 24 needs to be driven to move from left to right, the first in-out oil port 211 is selected as the oil inlet port, and the remaining in-out oil ports are selected as the oil return ports. When the piston 24 needs to be driven to move from right to left, the fifth in-out oil port 215 is selected as the oil inlet port, and the remaining in-out oil ports are selected as the oil return ports. Furthermore, the seven solenoid valves are electrically connected with a controller, the controller controls the opening and closing of the seven solenoid valves to control the extension and retraction of the multi-point positioning gear shift hydraulic cylinder 2 and the distance of the extension and retraction, so as to control the movement and positioning of the multi-point positioning gear shift hydraulic cylinder 2 between the five points, thereby driving the gear shift gearbox 1 to cycle between the low, medium, and high gears. In the initial state, all solenoid valves are de-energized, the piston 24 is at the leftmost end, and the gear shift gearbox 1 is in the low gear. When the first solenoid valve 41 and the third solenoid valve 43 are energized at the same time, the piston 24 moves to the position of the second annular groove 222 and is positioned, and the gear shift gearbox 1 is switched from the low gear to the first neutral gear. When the first solenoid valve 41 and the fourth solenoid valve 44 are energized at the same time, the piston 24 moves to the position of the third annular groove 223 and is positioned, and the gear shift gearbox 1 is switched from the first neutral gear to the medium gear. When the first solenoid valve 41 and the fifth solenoid valve 45 are energized at the same time, the piston 24 moves to the position of the fourth annular groove 224 and is positioned, and the gear shift gearbox 1 is switched from the medium gear to the second neutral gear. When the first solenoid valve 41 and the sixth solenoid valve 46 are energized at the same time, the piston 24 moves to the rightmost end, and the gear shift gearbox 1 is switched from the second neutral gear to the high gear.

[0039] In addition, the hydraulic control valve group 4 further comprises a one-way valve 48, a pressure reducing overflow valve 49 and an overflow valve 410, which are sequentially arranged on the oil supply path in the oil supply direction, and the overflow valve 410 is arranged between the oil supply path and the oil return path. Among them, the pressure reducing overflow valve 49 is used to maintain the shift pressure in the shift hydraulic system stable within the set pressure range, and the shift pressure value can be set according to the need of the shift force. The overflow valve 410 is used for system unloading and safety protection of the shift hydraulic system.

[0040] Optionally, a gear detection block 231 is installed on one end of the double-out piston rod 23 away from the shift fork linkage mechanism 3, a sensor mounting plate 27 is installed on the outer cylinder 21, and five gear detection sensors 28 are arranged on the sensor mounting plate 27 in an interval. The gear detection sensors 28 are electrically connected with the controller. During the movement of the double-out piston rod 23, when the corresponding gear detection sensor 28 detects the gear detection block 231, the controller controls all the solenoid valves to lose power and stop supplying oil to the multi-point positioning shift hydraulic cylinder 2. Among them, the gear detection sensors 28 include a low gear detection sensor 281, a first neutral gear detection sensor 282, a middle gear detection sensor 283, a second neutral gear detection sensor 284 and a high gear detection sensor 285 arranged in sequence from left to right, which can realize position detection feedback of five gears, i.e. low gear, first neutral gear, middle gear, second neutral gear and high gear.

[0041] It can be understood that by arranging five gear detection sensors 28 to detect the gear detection block 231, position detection feedback of five gears can be realized. When the corresponding gear detection sensor 28 detects the gear detection block 231, the solenoid valves in the hydraulic control valve group 4 lose power and stop supplying oil to the multi-point positioning shift hydraulic cylinder 2, which further improves the shift success rate.

[0042] In addition, the installation position of the gear detection block 231 on the double-out piston rod 23 can be adjusted left and right to calibrate the optimal detection distance between the gear detection block 231 and the gear detection sensor 28. For example, the gear detection block 231 is installed on the double-out piston rod 23 through threaded connection, and the detection distance between the gear detection block 231 and the gear detection sensor 28 can be adjusted by rotating the gear detection block 231 to calibrate to the optimal detection distance, which improves the accuracy of gear detection and thus improves the shift success rate. Among them, the gear detection sensor 28 can adopt a proximity switch or a reflection type laser sensor.

[0043] It can be understood that, as Figure 6As shown, the variable gear box 1 comprises a motor input shaft 11, an output shaft 12, a shift fork shaft 13, a fork rocker 14, a low gear 15, a middle gear 16, a high gear 17, a low gear engaging gear 18, a shift fork gear 19, a high gear engaging gear 110 and a positioning ball 111, the motor input shaft 11 is drivingly connected with the hydraulic motor 100, the low gear 15, the middle gear 16 and the high gear 17 are fixedly connected with the motor input shaft 11, the low gear engaging gear 18 and the high gear engaging gear 110 are bearingly connected with the output shaft 12 and are engaged with the low gear 15 and the high gear 17 respectively, the shift fork gear 19 is slidingly connected with the output shaft 12, the fork rocker 14 is fixedly connected with the shift fork shaft 13 and the shift fork gear 19, the shift fork shaft 13 is fixedly connected with the shift fork linkage 3, the shift fork gear 19 is driven to slide left and right by the shift fork linkage 3, so that the gear shifting action of the variable gear box 1 is realized, at least five clamping grooves 131 are arranged on the shift fork shaft 13, and the positioning ball 111 is used to clamp into the corresponding clamping groove 131 after the gear shifting is successful, so as to position the shift fork shaft 13. When the shift fork gear 19 slides to the leftmost end and is engaged with the low gear engaging gear 18, the variable gear box 1 is in the low gear; when the shift fork gear 19 slides to be engaged with the middle gear 16, the variable gear box 1 is in the middle gear; when the shift fork gear 19 slides to be engaged with the high gear engaging gear 110, the variable gear box 1 is in the high gear; when the shift fork gear 19 slides to the position between the low gear engaging gear 18 and the middle gear 16, the variable gear box 1 is in the first neutral gear; when the shift fork gear 19 slides to the position between the middle gear 16 and the high gear engaging gear 110, the variable gear box 1 is in the second neutral gear.

[0044] It can be understood that the working process of the electro-hydraulic control system of the automatic gear shifting gearbox of the embodiment is (taking the movement of the piston 24 from left to right as an example):

[0045] It is assumed that the initial state of the piston 24 is at the leftmost end, i.e. the piston 24 is located at the position of the first annular groove 221, and is in the low gear, at this time, the gear position detection sensor 281 detects the gear position detection block 231, and all the electromagnetic valves are in the de-energized state.

[0046] During the shift from low gear to first neutral gear, the controller energizes both the first and third solenoid valves 41, 43 simultaneously, making the first and second oil inlet / outlet ports 211, 212 function as working oil ports. Hydraulic oil passes through the one-way valve 48 and the pressure-relief valve 49, then flows from the first oil inlet / outlet port 211 and the first annular groove 221 into the left chamber, pushing the piston 24 and the dual-exit piston rod 23 rightward. The hydraulic oil in the right chamber then flows back to the tank through the second annular groove 222. As the piston 24 moves from left to right, the second sealing ring 243 first moves to the position of the first set of oil holes 216 below the second annular groove 222. At this point, the hydraulic oil in the right chamber returns only through the second set of oil holes 217 and the second annular groove 222. The piston 24 and dual-exit piston rod 23 begin to decelerate until the second sealing ring 243 moves to the position of the second set of oil holes 217. At this point, the right chamber is deadlocked, and the piston 24 and dual-exit piston rod 23 cease movement. At this time, the first neutral position detection sensor 282 detects the gear position detection block 231 and feeds back to the controller. The controller controls the first solenoid valve 41 and the third solenoid valve 43 to lose power and stop supplying oil. At this time, the speed change gear box 1 switches to the first neutral gear.

[0047] During the shift from first neutral to mid-range, the controller energizes both the first and fourth solenoid valves 41, 44 simultaneously, making the first and third oil inlet / outlet ports 211, 213 function as working oil ports. Hydraulic oil passes through the one-way valve 48 and the pressure-relief valve 49, then flows from the first oil inlet / outlet port 211 and the first annular groove 221 into the left chamber, pushing the piston 24 and the dual-exit piston rod 23 further rightward. The hydraulic oil in the right chamber flows back to the tank through the third annular groove 223. As the piston 24 moves from left to right, the second sealing ring 243 first moves to the position of the first set of oil holes 216 below the third annular groove 223. At this point, the hydraulic oil in the right chamber returns only through the second set of oil holes 217 and the third annular groove 223. The piston 24 and dual-exit piston rod 23 begin to decelerate until the second sealing ring 243 moves to the position of the second set of oil holes 217. At this point, the right chamber is deadlocked, and the piston 24 and dual-exit piston rod 23 cease movement. At this time, the mid-gear position detection sensor 283 detects the gear position detection block 231 and feeds back to the controller. The controller controls the first solenoid valve 41 and the fourth solenoid valve 44 to lose power and stop supplying oil. At this time, the speed change gear box 1 switches to the mid-gear.

[0048] During the shift from neutral to second neutral, the controller energizes both the first and fifth solenoid valves 41, 45 simultaneously, making the first and fourth oil inlet / outlet ports 211, 214 function as working oil ports. Hydraulic oil flows through the one-way valve 48 and the pressure-relief valve 49, then enters the left chamber from the first oil inlet / outlet port 211 and the first annular groove 221, pushing the piston 24 and the dual-exit piston rod 23 further rightward. The hydraulic oil in the right chamber flows back to the tank through the fourth annular groove 224. As the piston 24 moves from left to right, the second sealing ring 243 first moves to the position of the first set of oil holes 216 below the fourth annular groove 224. At this point, the hydraulic oil in the right chamber returns only through the second set of oil holes 217 and the fourth annular groove 224. The piston 24 and dual-exit piston rod 23 begin to decelerate until the second sealing ring 243 moves to the position of the second set of oil holes 217. At this point, the right chamber is deadlocked, and the piston 24 and dual-exit piston rod 23 cease movement. At this time, the second neutral position detection sensor 284 detects the gear position detection block 231 and feeds back to the controller, and the controller controls the first solenoid valve 41 and the fifth solenoid valve 45 to lose power and stop oil supply. At this time, the speed change gear box 1 switches to the second neutral gear.

[0049] During the shift from second neutral to high gear, the controller energizes both the first and sixth solenoid valves 41, 46, with the first and fifth oil inlet / outlet ports 211, 215 acting as working oil ports. Hydraulic oil passes through the one-way valve 48 and the pressure relief valve 49, then flows from the first oil inlet / outlet port 211 and the first annular groove 221 into the left chamber, pushing the piston 24 and the dual-exit piston rod 23 further to the right. The hydraulic oil in the right chamber returns through the oil hole and the fifth annular groove 225. Piston 24 stops moving after reaching its rightmost position, i.e., reaching the position of the fifth annular groove 225. At this point, the high gear detection sensor 285 detects the gear position detection block 231 and provides feedback to the controller. The controller then de-energizes both the first and sixth solenoid valves 41, 46, stopping the oil supply. The speed change gearbox 1 now shifts to high gear.

[0050] It can be understood that the working principle of the piston 24 moving from right to left is the same as described above, with the only difference being that the fifth oil inlet and outlet 215 is used as the oil inlet and the remaining oil inlets and outlets are used as the oil outlets, so it will not be described in detail here.

[0051] In addition, another embodiment of the present invention further provides an agricultural machine, which preferably adopts the electro-hydraulic control system of the automatic shift transmission as described above.

[0052] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An electro-hydraulic control system for an automatic shift transmission, characterized in that: The invention comprises a speed change gear box (1), a multi-point positioning shift hydraulic cylinder (2), a shift fork linkage mechanism (3), a hydraulic control valve group (4) and a controller, wherein the speed change gear box (1) is connected to a hydraulic motor (100) for driving and transmitting power, a piston rod of the multi-point positioning shift hydraulic cylinder (2) is connected to the speed change gear box (1) through the shift fork linkage mechanism (3) and is used to drive the speed change gear box (1) to perform cyclic switching of at least three gear positions, the hydraulic control valve group (4) is connected to an external oil source and the multi-point positioning shift hydraulic cylinder (2) respectively and is used to provide pressure oil to the multi-point positioning shift hydraulic cylinder (2), the hydraulic control valve group (4) is electrically connected to the controller, and the controller controls the working state of the hydraulic control valve group (4) to drive the multi-point positioning shift hydraulic cylinder (2) to move and position between at least five points, thereby driving the speed change gear box (1) to perform cyclic switching of at least three gear positions; The multi-point positioning shift hydraulic cylinder (2) includes an external cylinder body (21), an intermediate transition cylinder barrel (22), a double-outlet piston rod (23), a piston (24) and an end cover (25). The intermediate transition cylinder barrel (22) is arranged in the external cylinder body (21). The end covers (25) are arranged at both ends of the external cylinder body (21) and are used to fix the intermediate transition cylinder barrel (22). The double-outlet piston rod (23) is installed in the intermediate transition cylinder barrel (22) and its two ends extend out of the end cover (25). One end of the double-outlet piston rod (23) is connected to the shift fork linkage mechanism (3). The piston (24) is located in the intermediate transition cylinder barrel (22) and is fixedly installed in the double-outlet piston rod. On the piston rod (23), at least five oil inlet and outlet ports are provided on the external cylinder body (21), and at least five annular grooves are provided on the intermediate transition cylinder barrel (22), each oil inlet and outlet port is connected to a corresponding annular groove, and each annular groove is connected to the inner cavity of the intermediate transition cylinder barrel (22) through at least one group of oil holes, the oil inlet and outlet ports on the external cylinder body (21) are connected to the hydraulic control valve group (4), and the opening and closing of each oil inlet and outlet port are controlled by the hydraulic control valve group (4), and the controller controls the working state of the hydraulic control valve group (4) to select any two oil inlet and outlet ports as working oil ports to drive the double-outlet piston rod (23) to move and position between at least five points; The outer cylinder body (21) is provided with a first oil inlet and outlet (211), a second oil inlet and outlet (212), a third oil inlet and outlet (213), a fourth oil inlet and outlet (214) and a fifth oil inlet and outlet (215) in sequence from left to right, and the intermediate transition cylinder barrel (22) is provided with a first annular groove (221), a second annular groove (222), a third annular groove (223), a fourth annular groove (224) and a fifth annular groove (225) in sequence from left to right, and the five oil inlet and outlet ports are in one-to-one communication with the five annular grooves; When the piston (24) moves to the position of the first annular groove (221), the speed change gear box (1) is in low gear, when the piston (24) moves to the position of the second annular groove (222), the speed change gear box (1) switches to the first neutral gear, when the piston (24) moves to the position of the third annular groove (223), the speed change gear box (1) switches to the middle gear, when the piston (24) moves to the position of the fourth annular groove (224), the speed change gear box (1) switches to the second neutral gear, and when the piston (24) moves to the position of the fifth annular groove (225), the speed change gear box (1) switches to the high gear.

2. The electro-hydraulic control system of the automatic shift transmission according to claim 1, characterized in that: The middle part of the piston (24) is a guide ring (241), and a first sealing ring (242) and a second sealing ring (243) are respectively provided on both sides of the guide ring (241). The first annular groove (221) and the fifth annular groove (225) are communicated with the inner cavity of the intermediate transition cylinder (22) through a group of oil holes. The second annular groove (222), the third annular groove (223), and the fourth annular groove (224) are respectively communicated with the inner cavity of the intermediate transition cylinder (22) through two groups of oil holes. The two groups of oil holes include a first group of oil holes (216) and a second group of oil holes (217) arranged in sequence from left to right, and the spacing between the two groups of oil holes is the same as the spacing between the two sealing rings. During the movement of the double-outlet piston rod (23) from left to right, when the second sealing ring (243) moves to the position of the first group of oil holes (216), the double-outlet piston rod (23) starts to decelerate. When the second sealing ring (243) moves to the position of the second group of oil holes (217), the right chamber is in a dead-locked state, and the double-outlet piston rod (23) stops moving to achieve positioning. During the movement of the double-outlet piston rod (23) from right to left, when the first sealing ring (242) moves to the position of the second group of oil holes (217), the double-outlet piston rod (23) starts to decelerate. When the first sealing ring (242) moves to the position of the first group of oil holes (216), the left chamber is in a dead-locked state, and the double-outlet piston rod (23) stops moving to achieve positioning.

3. The electro-hydraulic control system of the automatic shift transmission according to claim 2, characterized in that: The hydraulic control valve group (4) includes a first solenoid valve (41), a second solenoid valve (42), a third solenoid valve (43), a fourth solenoid valve (44), a fifth solenoid valve (45), a sixth solenoid valve (46) and a seventh solenoid valve (47). The first solenoid valve (41) is connected to an external oil source and a first oil inlet and outlet (211), respectively. The seventh solenoid valve (47) is connected to an external oil source and a fifth oil inlet and outlet (215), respectively. The second solenoid valve (42), the third solenoid valve (43), the fourth solenoid valve (44), the fifth solenoid valve (45) and the sixth solenoid valve (46) are connected to the first oil inlet and outlet (211), the second oil inlet and outlet (212), respectively. ), the third oil inlet and outlet (213), the fourth oil inlet and outlet (214) and the fifth oil inlet and outlet (215) are connected correspondingly, and the second solenoid valve (42), the third solenoid valve (43), the fourth solenoid valve (44), the fifth solenoid valve (45) and the sixth solenoid valve (46) are all connected to the external oil tank, and the seven solenoid valves are all electrically connected to the controller. The controller controls the multi-point positioning shift hydraulic cylinder (2) to move and position between the five points by controlling the on and off of the seven solenoid valves, thereby driving the speed change gear box (1) to cyclically switch between the low, medium and high gears.

4. The electro-hydraulic control system of the automatic shift transmission according to claim 3, characterized in that: In the initial state, all electromagnetic valves are de-energized, the piston (24) is at the far left end, and the speed change gear box (1) is in low gear; when the first electromagnetic valve (41) and the third electromagnetic valve (43) are energized at the same time, the piston (24) moves to the position of the second annular groove (222) and is positioned, and the speed change gear box (1) switches from low gear to the first neutral gear; when the first electromagnetic valve (41) and the fourth electromagnetic valve (44) are energized at the same time, the piston (24) moves to the position of the third annular groove (223) and is positioned, and the speed change gear box (1) switches from low gear to the first neutral gear; ) is positioned and located, and the speed change gear box (1) switches from the first neutral gear to the middle gear; when the first solenoid valve (41) and the fifth solenoid valve (45) are energized at the same time, the piston (24) moves to the position of the fourth annular groove (224) and is positioned, and the speed change gear box (1) switches from the middle gear to the second neutral gear; when the first solenoid valve (41) and the sixth solenoid valve (46) are energized at the same time, the piston (24) moves to the rightmost end, and the speed change gear box (1) switches from the second neutral gear to the high gear.

5. The electro-hydraulic control system of the automatic shift transmission as claimed in claim 3, characterized in that: A gear position detection block (231) is installed on one end of the double-outlet piston rod (23) away from the shift fork linkage mechanism (3), a sensor mounting plate (27) is installed on the external cylinder body (21), and five gear position detection sensors (28) are arranged at intervals on the sensor mounting plate (27), and the gear position detection sensors (28) are electrically connected to the controller. During the movement of the double-outlet piston rod (23), when the corresponding gear position detection sensor (28) detects the gear position detection block (231), the controller controls the solenoid valves to lose power and stop supplying oil to the multi-point positioning shift hydraulic cylinder (2).

6. The electro-hydraulic control system of the automatic shift transmission as claimed in claim 3, characterized in that: The hydraulic control valve group (4) further comprises a one-way valve (48), a pressure reducing and relief valve (49) and a relief valve (410), wherein the one-way valve (48) and the pressure reducing and relief valve (49) are sequentially arranged on the oil supply line along the oil supply direction, and the relief valve (410) is arranged between the oil supply line and the oil return line.

7. The electro-hydraulic control system of the automatic shift transmission according to claim 1, wherein: The speed change gearbox (1) comprises a motor input shaft (11), an output shaft (12), a shift fork shaft (13), a shift fork rocker (14), a low-speed gear (15), an intermediate gear (16), a high-speed gear (17), a low-speed meshing gear (18), a shift fork gear (19), a high-speed meshing gear (110) and a positioning bead (111), wherein the motor input shaft (11) is drivingly connected to the hydraulic motor (100), the low-speed gear (15), the intermediate gear (16) and the high-speed gear (17) are all fixedly connected to the motor input shaft (11), the low-speed meshing gear (18) and the high-speed meshing gear (110) are connected to the bearing of the output shaft (12), and are respectively connected to the low-speed gear ( 15) and the high-speed gear (17) are meshed, the shift fork gear (19) is meshed with the output shaft (12) and is slidably connected, the shift fork rocker (14) is fixedly connected to the shift fork shaft (13) and the shift fork gear (19), the shift fork shaft (13) is fixedly connected to the shift fork linkage mechanism (3), and the shift fork gear (19) is driven to slide left and right by the shift fork linkage mechanism (3), thereby realizing the shifting action of the speed change gear box (1), at least five card slots (131) are provided on the shift fork shaft (13), and the positioning card bead (111) is used to be clamped into the corresponding card slot (131) after the gear shift is successful, so as to position the shift fork shaft (13); When the shift fork gear (19) slides to the leftmost end and meshes with the low-gear meshing gear (18), the speed change gear box (1) is in low gear; when the shift fork gear (19) slides to mesh with the intermediate gear (16), the speed change gear box (1) is in intermediate gear; when the shift fork gear (19) slides to mesh with the high-gear meshing gear (110), the speed change gear box (1) is in high gear; when the shift fork gear (19) slides to a position between the low-gear meshing gear (18) and the intermediate gear (16), the speed change gear box (1) is in a first neutral gear; when the shift fork gear (19) slides to a position between the intermediate gear (16) and the high-gear meshing gear (110), the speed change gear box (1) is in a second neutral gear.

8. An agricultural machine, characterized in that: An electro-hydraulic control system for an automatic shift transmission as claimed in any one of claims 1 to 7.

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