A hydraulic system for an automatic transmission

Abstract

This invention relates to a hydraulic system for an automatic transmission, belonging to the field of automatic transmission technology. It includes an oil pump, a TC valve, a torque converter, a clutch, a manual shift valve, a first shift fork drive valve, a second shift fork drive valve, a third shift fork drive valve, a first directional valve, and a second directional valve. The manual directional valve forcibly cuts off the clutch oil supply when in mechanical neutral (N) gear. By setting a multi-stage relief valve at the front end of the TC valve, the unlocking and locking pressures of the torque converter can be limited. A first-stage relief valve is connected to the rear end of the clutch solenoid valve, prioritizing the oil supply to the shifting and clutch circuits during clutch switching, thus shortening the shifting response time. A cooling bypass valve is designed at the front end of the cooler, allowing oil to overflow directly to the lubrication end when the pressure at the front end of the cooler is high. The oil pressure feedback from the cooling lubrication end is sent to a throttle valve; when there is excessive oil at the rear end, the oil pump's outlet is directly adjusted from the front end through the throttle valve, improving system efficiency.

Description

Technical Field

[0001] This invention belongs to the field of automatic transmission technology, and specifically relates to a hydraulic system for automatic transmissions. Background Technology

[0002] As a core component of power transmission in modern vehicles, the performance of automatic transmissions directly impacts driving experience and fuel economy. The hydraulic control system is a key actuator in automatic transmissions, responsible for clutch engagement, gear shifting, and lubrication and cooling. Its response speed and reliability directly determine shift smoothness and system lifespan. Traditional hydraulic systems face significant technical bottlenecks in terms of performance, cost, and safety.

[0003] For example, traditional hydraulic systems often use a single mechanical oil pump, which is prone to insufficient oil supply at low speeds, leading to sluggish response, while at high speeds, overflow losses result in energy waste. While electronic oil pumps can alleviate this problem, they are bulky, require additional power, and are more expensive, making them unsuitable for the current automotive industry's pursuit of extreme cost-effectiveness. For instance, the Aisin AW series transmissions from Japan suffer from insufficient oil supply at low speeds, causing shift delays (response time > 200ms), and overflow losses reaching 15% at high speeds; mechanical valves are susceptible to oil contamination, with pressure fluctuations ranging from ±20%, causing shift shocks.

[0004] Furthermore, most of the hydraulic systems of the transmissions do not have a reverse gear locking function, which poses a safety hazard. Existing reverse gear locking mechanisms are also relatively complex, occupy a lot of space, and are costly. For example, in the invention patent CN102678910A "Vehicle Transmission Reverse Gear Locking Device", the reverse gear locking device includes a fixed block (1) fixed relative to the transmission housing, a reverse gear locking block (2), a shift shaft (3), a reset device, a shift head (4), an interlocking shift block (5), a first locking arm (21), a second locking arm (22) ... a first elastic device (71), a second elastic device (72), etc., which are complex in structure, have low integration, high cost, and are difficult to adapt to the layout of compact transmissions. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and proposes a hydraulic system for automatic transmissions to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution.

[0007] A hydraulic system for an automatic transmission includes an oil pump, a TC valve, a torque converter, a clutch, a manual shift valve, a first shift fork actuation valve, a second shift fork actuation valve, a third shift fork actuation valve, a first directional valve, and a second directional valve. A primary oil circuit is connected to the outlet of the oil pump. A secondary oil circuit is connected to the primary oil circuit via a solenoid oil supply valve. A primary relief valve is connected to the primary oil circuit and is connected to the TC valve via a relief oil circuit. A TC control solenoid valve is connected to the secondary oil circuit and is connected to the TC valve via a control oil circuit. The TC valve is connected to the torque converter and has a cooling oil circuit. The primary oil circuit is connected to the manual shift valve... A clutch solenoid valve is connected between the shift valves. A clutch is connected to the manual shift valve. A first shift solenoid valve and a second shift solenoid valve are connected between the first-stage oil circuit and the first directional valve. A first gear selection solenoid valve is connected between the second-stage oil circuit and the first directional valve. A second gear selection solenoid valve is connected between the second-stage oil circuit and the second directional valve. The second directional valve is connected to the first directional valve. A first shift fork drive valve is connected to the first directional valve. A second shift fork drive valve and a third shift fork drive valve are connected to the second directional valve. A reverse gear lock is provided on the third shift fork drive valve. The reverse gear lock is connected to the manual shift valve. The manual shift valve is connected to the first-stage oil circuit through a straight-through oil circuit.

[0008] Furthermore, the oil pump is a dual-outlet oil pump, with both outlets converging at the primary oil circuit; the oil pump's suction port is connected to a suction filter, and the suction filter's inlet is connected to the oil tank; a check valve is installed at the first outlet of the oil pump; a throttle valve is connected to the first outlet of the oil pump via an oil circuit; a system safety valve is installed in parallel between the oil pump's suction port and outlet; the drain ports of both the throttle valve and the system safety valve are connected to the oil pump's suction port.

[0009] Furthermore, the overflow oil circuit includes a primary overflow oil circuit and a secondary overflow oil circuit. A primary overflow oil circuit and a secondary overflow oil circuit are connected in parallel at the outlet of the primary overflow valve. A secondary overflow valve is installed on the secondary overflow oil circuit, and a tertiary overflow valve is connected to the secondary overflow oil circuit through an oil circuit.

[0010] Furthermore, the TC valve has a first control port and a second control port at both ends. The TC valve has two oil inlets, one independent oil outlet, four working oil ports, and one independent pressure relief port. The first oil inlet of the TC valve is connected to the secondary overflow oil circuit, the second oil inlet of the TC valve is connected to the primary overflow oil circuit, the independent oil outlet of the TC valve is connected to the cooling oil circuit, the first working oil port of the TC valve is connected to the oil outlet of the hydraulic torque converter, the second working oil port of the TC valve is connected to the oil inlet of the hydraulic torque converter, the third oil port of the TC valve is connected to the second control port on the right end of the TC valve through a connecting oil circuit, and the fourth working oil port of the TC valve is connected to the connecting oil circuit.

[0011] Furthermore, the solenoid TC valve is provided with a pressure feedback port, an oil inlet, an oil outlet, and a working oil port. The pressure feedback port is located at one end of the return spring of the solenoid TC valve and is connected to the working oil port. The oil inlet of the TC control solenoid valve is connected to the first-stage oil circuit. The working oil port of the TC control solenoid valve is connected to the first control port on the left end of the TC valve. The oil outlet of the TC control solenoid valve is connected to the oil tank. The pressure feedback port of the TC control solenoid valve is connected to the control end of the throttle valve.

[0012] Furthermore, a cooler and a filter press are sequentially installed on the cooling oil circuit, and a lubricating oil circuit is installed at the outlet end of the cooling oil circuit, which is connected to each lubrication point of the automatic transmission hydraulic system; a cooling bypass circuit is installed in parallel on the cooling oil circuit, and a cooling bypass valve is installed on the cooling bypass circuit.

[0013] Furthermore, the manual shift valve is provided with two pressure relief ports and four interfaces, wherein the four interfaces are respectively connected to the clutch solenoid valve, the clutch, the reverse gear lock, and the straight-through oil circuit.

[0014] Furthermore, the first shift fork drive valve is a 1 / 2 gear shift fork drive valve, the second shift fork drive valve is a 3 / 4 gear shift fork drive valve, and the third shift fork drive valve is a 5 / R gear shift fork drive valve.

[0015] Furthermore, both the first and second directional control valves are provided with six ports and three pressure relief ports. A control port is provided at the end of both valves furthest from the return spring. The first and second ports on the first directional control valve are connected to the first and second shift solenoid valves, respectively, and the control port on the first directional control valve is connected to the first gear selection solenoid valve. The third and fourth ports on the first directional control valve are connected to the ports at both ends of the first shift fork drive valve. The fifth and sixth ports on the first directional control valve are connected to the first and second ports on the second directional control valve, respectively. The third and fourth ports on the second directional control valve are connected to both ends of the second shift fork drive valve, and the fifth and sixth ports on the second directional control valve are connected to both ends of the third shift fork drive valve. The control port on the second directional control valve is connected to the second gear selection solenoid valve.

[0016] Furthermore, the first shift solenoid valve, the second shift solenoid valve, the first gear selection solenoid valve, and the second gear selection solenoid valve are all two-position three-way valves; the first shift solenoid valve and the first gear selection solenoid valve are normally open, and the second shift solenoid valve and the second gear selection solenoid valve are normally closed.

[0017] The beneficial effects of this invention compared to the prior art are as follows: This hydraulic system, building upon basic torque converter, clutch, and shift control, aims to address issues such as poor compatibility and high cost due to low integration in traditional automatic transmissions; safety design deficiencies leading to safety hazards like incorrect reverse gear engagement; low-cost linkage between the manual DNR shift lever and the hydraulic system; insufficient oil supply causing sluggish response and high-speed overflow energy waste; easy wear of the torque converter under pressure shocks; and poor low-temperature start-up responsiveness. It also prevents wear caused by insufficient cooling and lubrication. Furthermore, the system's clutch tooling status feedback valve design and rear-end pressure feedback throttle valve design not only improve system stability and response speed, resulting in more precise control and improved shift responsiveness, but also reduce the demands on the oil pump, thereby increasing transmission efficiency and reducing powertrain fuel consumption.

[0018] This hydraulic system can utilize a manual directional valve to forcibly cut off the clutch oil supply circuit in mechanical neutral (N) gear, ensuring absolute system safety. By installing a multi-stage relief valve at the front end of the TC valve, the unlocking and locking pressures of the torque converter can be limited. A relief valve is connected to the rear end of the clutch solenoid valve, prioritizing oil supply to the shifting and clutch circuits during clutch switching, shortening shifting response time. A cooling bypass valve is designed at the front end of the cooler, allowing oil to overflow directly to the lubrication end when the pressure at the front end of the cooler is high, saving system energy. The oil pressure feedback from the cooling lubrication end is sent to the throttle valve; when there is excessive oil at the rear end, the throttle valve directly adjusts one outlet of the oil pump from the front end, improving system efficiency. Oil overflowing from the system safety valve and throttle valve is connected to the oil pump's suction port (after the suction filter), effectively improving the overall low-temperature response performance of the hydraulic system. Attached Figure Description

[0019] The present invention will now be described in further detail with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the hydraulic torque converter in the unlocked state. Figure 3 This is a schematic diagram of the hydraulic torque converter in the lock-up condition. Figure 4 This is a schematic diagram of the structure when the manual shift valve is in D gear and the first shift fork drive valve is adjusted to first gear; Figure 5 This is a schematic diagram of the structure when the manual shift valve is in the D position and the first shift fork drive valve is adjusted to the second position; Figure 6 This is a schematic diagram of the structure when the manual shift valve is in D gear and the first shift fork drive valve is adjusted to the third gear. Figure 7 This is a schematic diagram of the structure when the manual shift valve is in D gear and the first shift fork drive valve is adjusted to fourth gear. Figure 8 This is a schematic diagram of the structure when the manual shift valve is in D gear and the first shift fork drive valve is adjusted to the fifth gear. Figure 9 This is a schematic diagram of the manual shift valve when it is in neutral (N) position. Figure 10 This is a schematic diagram of the manual shift valve when it is in reverse (R) position. Among them, 1 is the oil pump, 2 is the primary oil circuit, 3 is the solenoid oil supply valve, 4 is the secondary oil circuit, 5 is the primary relief valve, 6 is the TC valve, 7 is the TC control solenoid valve, 8 is the control oil circuit, 9 is the hydraulic torque converter, 10 is the cooling oil circuit, 11 is the manual shift valve, 12 is the clutch solenoid valve, 13 is the clutch, 14 is the first shift solenoid valve, 15 is the second shift solenoid valve, 16 is the first directional valve, 17 is the second directional valve, 18 is the first gear selection solenoid valve, 19 is the second gear selection solenoid valve, 20 is the first shift fork drive valve, 21 is the second shift fork drive valve, 22 is the third shift fork drive valve, 23 is the reverse lock, 24 is the straight-through oil circuit, 25 is the suction filter, and 26 is the single... 27 is a throttle valve, 28 is a system safety valve, 29 is a primary overflow oil circuit, 30 is a secondary overflow oil circuit, 31 is a secondary overflow valve, 32 is a tertiary overflow valve, 33 is a first control port, 34 is a second control port, 35 is a first oil inlet, 36 is a second oil inlet, 37 is an independent oil outlet, 38 is an independent pressure relief port, 39 is a first working oil port, 40 is a second working oil port, 41 is a third working oil port, 42 is a fourth working oil port, 43 is a connecting oil circuit, 44 is a cooler, 45 is a filter press, 46 is a lubricating oil circuit, 47 is a cooling bypass circuit, 48 is a cooling bypass valve, 49 is an accumulator, 50 is a valve body oil filter, and 51 is a pressure sensor. Detailed Implementation

[0020] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0021] like Figure 1As shown, this invention provides a hydraulic system for an automatic transmission, including an oil pump 1, a TC valve 6, a torque converter 9, a clutch 13, a manual shift valve 11, a first shift fork drive valve 20, a second shift fork drive valve 21, a third shift fork drive valve 22, a first directional valve 16, and a second directional valve 17. A primary oil circuit 2 is connected to the outlet of the oil pump 1. A secondary oil circuit 4 is connected to the primary oil circuit 2 via a solenoid oil supply valve 3. A primary relief valve 5 is connected to the primary oil circuit 2 and is connected to the TC valve 6 via a relief oil circuit. A TC control solenoid valve 7 is connected to the secondary oil circuit 4 and is connected to the TC valve 6 via a control oil circuit 8. The TC valve 6 is connected to the torque converter 9 and is connected to a cooling oil circuit 10. The primary oil circuit 2 is connected to the manual shift valve 11. A clutch solenoid valve 12 is connected between valves 11. A clutch 13 is connected to the manual shift valve 11. A first shift solenoid valve 14 and a second shift solenoid valve 15 are connected between the first-stage oil circuit 2 and the first directional valve 16. A first gear selection solenoid valve 18 is connected between the second-stage oil circuit 4 and the first directional valve 16. A second gear selection solenoid valve 19 is connected between the second-stage oil circuit 4 and the second directional valve 17. The second directional valve 17 is connected to the first directional valve 16. A first shift fork drive valve 20 is connected to the first directional valve 16. A second shift fork drive valve 21 and a third shift fork drive valve 22 are connected to the second directional valve 17. A reverse gear lock 23 is provided on the third shift fork drive valve 22. The reverse gear lock 23 is connected to the manual shift valve 11. The manual shift valve 11 is connected to the first-stage oil circuit 2 through a straight-through oil circuit 24.

[0022] The oil pump 1 is a dual-outlet oil pump 1, with both outlets converging at the primary oil circuit 2. The suction port of oil pump 1 is connected to the suction filter 25, and the inlet of the suction filter 25 is connected to the oil tank. A one-way valve 26 is installed at the first outlet of oil pump 1. A throttle valve 27 is connected to the first outlet of oil pump 1 via an oil circuit, with the oil circuit containing the throttle valve 27 located between the first outlet and the one-way pump. A system safety valve 28 is connected in parallel between the suction port and the outlet of oil pump 1. The drain ports of both the throttle valve 27 and the system safety valve 28 are connected to the suction port of oil pump 1, which can improve the problems of slow response, unstable pressure, and vibration caused by high oil viscosity at low temperatures during startup, leading to pressure buildup at the system's downstream end and difficulty in suction at the oil filter. When the system pressure is too high, pressure can be released through the system safety valve 28. This structure allows for switching between single and dual pumps, ensuring pressure at low speeds and reducing relative displacement at high speeds, achieving energy saving and efficiency improvement.

[0023] The electromagnetic oil supply valve 3 is a pressure reducing valve. After the oil in the first-stage oil circuit 2 is reduced in pressure by the electromagnetic oil supply valve 3, it is supplied to the first gear selection solenoid valve 18, the second gear selection solenoid valve 19, and the TC control solenoid valve 7 on the second-stage oil circuit 4.

[0024] The first gear selection solenoid valve 18, the second gear selection solenoid valve 19, and the TC control solenoid valve 7 can be high-pressure adapted solenoid valves. In this way, the solenoid oil supply valve 3 can be directly omitted from the system, and the first gear selection solenoid valve 18, the second gear selection solenoid valve 19, and the TC control solenoid valve 7 can be directly connected to the first-stage oil circuit 2.

[0025] The first shift solenoid valve 14, the second shift solenoid valve 15, and the clutch solenoid valve 12 can be equipped with low-pressure adapted solenoid valves to save costs. They are connected to the secondary oil circuit 4 and supplied with oil by the secondary oil circuit 4.

[0026] The overflow oil circuit includes a primary overflow oil circuit 29 and a secondary overflow oil circuit 30. The primary overflow oil circuit 29 and the secondary overflow oil circuit 30 are connected in parallel at the outlet of the primary overflow valve 5. A secondary overflow valve 31 is installed on the secondary overflow oil circuit 30. A tertiary overflow valve 32 is connected to the secondary overflow oil circuit 30 through an oil circuit. The tertiary overflow valve 32 is located on the outlet side of the secondary overflow valve 31.

[0027] The TC valve 6 has a first control port 33 and a second control port 34 at its two ends. The second control port 34 is located at one end of the return spring of the TC valve 6. The TC valve has a sliding main valve core inside. The TC valve has two oil inlets, one independent oil outlet 37, four working oil ports and one independent pressure relief port 38.

[0028] The first oil inlet 35 of TC valve 6 is connected to the secondary overflow oil circuit 30, the second oil inlet 36 of TC valve 6 is connected to the primary overflow oil circuit 29, the independent oil outlet 37 of TC valve 6 is connected to the cooling oil circuit 10, the first working oil port 39 of TC valve 6 is connected to the oil outlet of hydraulic torque converter 9, the second working oil port 40 of TC valve 6 is connected to the oil inlet of hydraulic torque converter 9, the third oil port of TC valve 6 is connected to the second control port 34 on the right end of TC valve 6 through the connecting oil circuit 43, and the fourth working oil port 42 of TC valve 6 is connected to the connecting oil circuit 43.

[0029] The electromagnetic TC valve 6 is a two-position three-way valve with pressure feedback. The electromagnetic TC valve 6 is provided with a pressure feedback port, an oil inlet, an oil outlet, and a working oil port. The pressure feedback port is located at one end of the return spring of the electromagnetic TC valve 6 and is connected to the working oil port. The oil inlet of the TC control solenoid valve 7 is connected to the first-stage oil circuit 2. The working oil port of the TC control solenoid valve 7 is connected to the first control port 33 on the left end of the TC valve 6. The oil outlet of the TC control solenoid valve 7 is connected to the oil tank. The pressure feedback port of the TC control solenoid valve 7 is connected to the control end of the throttle valve 27.

[0030] A cooler 44 and a filter press 45 are sequentially arranged on the cooling oil circuit 10. A lubricating oil circuit 46 is provided at the outlet end of the cooling oil circuit 10, and the lubricating oil circuit 46 is connected to each lubrication point of the automatic transmission hydraulic system. A cooling bypass circuit 47 is arranged in parallel on the cooling oil circuit 10, and a cooling bypass valve 48 is provided on the cooling bypass circuit 47. One end of the cooling bypass circuit 47 is connected to the cooling oil circuit 10 before the inlet of the cooler 44, and one end of the cooling bypass circuit 47 is connected to the inlet end of the lubricating oil circuit 46, so that the cooling bypass circuit 47 bypasses the cooler 44 and the filter press 45 and is directly connected to the lubricating oil circuit 46.

[0031] After passing through various lubrication points, the lubrication oil passage 46 connects to the oil pan.

[0032] The cooling bypass valve 48 includes a valve body, a valve core, and an elastic element that provides preload. When the pressure on the oil inlet side of the cooling bypass valve 48 reaches the preset opening pressure value (P0), the cooling bypass valve 48 opens, allowing a portion of the oil in the cooling oil circuit 10 to be discharged from its outlet and flow directly into the lubricating oil circuit 46 along the cooling bypass circuit 47.

[0033] An accumulator 49 is connected to the inlet side of the cooler 44 via an oil circuit. The accumulator 49 is used to prevent pressure fluctuations at the downstream end of the hydraulic system. The connection end of the accumulator 49 is connected to the control end of the throttle valve 27.

[0034] The manual shift valve 11 is provided with two pressure relief ports and four interfaces, the four interfaces being connected to the clutch solenoid valve 12, the clutch 13, the reverse gear lock 23, and the straight-through oil circuit 24, respectively.

[0035] The clutch solenoid valve 12 is a normally open two-position three-way valve. A valve body filter 50 is installed in the oil circuit between the clutch solenoid valve 12 and the manual shift valve 11. The clutch solenoid valve 12 controls the flow of oil in the primary oil circuit 2 through the valve body filter 50 and the manual shift valve 11 to the clutch 13. The valve body filter 50 mainly serves a preventive and protective function to prevent impurities in the hydraulic chamber of the clutch 13 from flowing back into the hydraulic system and causing valve core jamming.

[0036] A pressure sensor 51 is installed in the oil circuit between the manual shift valve 11 and the clutch 13. By collecting the pressure signal from the pressure sensor 51, the opening of the clutch solenoid valve 12 can be adjusted, thereby achieving gradient control of the clutch 13.

[0037] This system repeatedly arranges the oil circuits from clutch solenoid valve 12 to clutch 13, which can realize dual-clutch control.

[0038] The first shift fork drive valve 20 is a 1 / 2 gear shift fork drive valve. By controlling the liquid to be introduced into one of the two ends of the first shift fork drive valve 20, the first shift fork drive valve 20 can be selectively adjusted to the first gear or the second gear.

[0039] The second shift fork drive valve 21 is a 3 / 4 gear shift fork drive valve. By controlling the liquid to be introduced into one of the two ends of the second shift fork drive valve 21, the second shift fork drive valve 21 can be selectively adjusted to three gears or four gears.

[0040] The third shift fork drive valve 22 is a 5 / R gear shift fork drive valve. By controlling the liquid to be introduced into one of the two ends of the third shift fork drive valve 22, the third shift fork drive valve 22 can be selectively adjusted to the 5th gear or the R gear.

[0041] The first shift solenoid valve 14, the second shift solenoid valve 15, the first gear selection solenoid valve 18, and the second gear selection solenoid valve 19 are all two-position three-way valves.

[0042] Both the first reversing valve 16 and the second reversing valve 17 are provided with six ports and three pressure relief ports. A control port is provided at the end of the first reversing valve 16 and the second reversing valve 17 away from the return spring.

[0043] The first and second ports on the first directional control valve 16 are connected to the first shift solenoid valve 14 and the second shift solenoid valve 15, respectively. The control port on the first directional control valve 16 is connected to the first gear selection solenoid valve 18. The third and fourth ports on the first directional control valve 16 are connected to the ports at both ends of the first shift fork drive valve 20, respectively. The fifth and sixth ports on the first directional control valve 16 are connected to the first and second ports on the second directional control valve 17, respectively.

[0044] The third and fourth ports on the second directional valve 17 are connected to the two ends of the second shift fork drive valve 21, the fifth and sixth ports on the second directional valve 17 are connected to the two ends of the third shift fork drive valve 22, and the control port of the second directional valve 17 is connected to the second gear selection solenoid valve 19.

[0045] The manual shift valve 11 is controlled by the vehicle's shift lever and can be in "D / N / R" positions.

[0046] When the flow rate in the clutch and shifting oil circuit is sufficient, the first-stage relief valve 5 will connect the oil in the first-stage oil circuit 2 with the oil circuit of the hydraulic torque converter 9 to ensure the normal operation of the clutch and shifting system.

[0047] The working port of the clutch solenoid valve 12 is connected to the control terminal of the first-stage relief valve 5, which is regulated by pressure feedback from the clutch solenoid valve 12. During normal vehicle operation, the clutch 13 remains open, and the pressure of the clutch 13 is fed back to the first-stage relief valve 5, increasing the opening of the first-stage relief valve 5 to supply oil to the rear. When shifting gears, the clutch 13 needs to disengage before engaging again, reducing the pressure fed back to the first-stage relief valve 5. This allows the first-stage oil circuit 2 to prioritize supplying oil to the clutch, shifting system, and second-stage oil circuit 4, ensuring system stability and response speed, and making the entire system control more precise.

[0048] like Figure 2 As shown, the hydraulic torque converter 9 is in the unlocked condition: When the TC control solenoid valve 7 is in its initial state, its inlet port is connected to its working port. The oil inside the first-stage oil circuit 2 is directly input to the first control port 33 on the left side of the TC valve 6 through the control oil circuit 8. At this time, the first inlet port 35 of the TC valve 6 is connected to the second working port 40, the first working port 39 is connected to the independent outlet port 37, the second inlet port 36 and the third working port 41 are both closed, and the fourth working port 42 is connected to the independent pressure relief port 38. Thus, the second control port 34 on the right side of the TC valve 6 is directly connected to the independent pressure relief port 38 through the connecting oil circuit 43 and the fourth working port 42.

[0049] When the oil pressure inside the primary oil circuit 2 exceeds the set pressure of the primary relief valve 5, the oil inside the primary oil circuit 2 enters the primary relief oil circuit 29 and the secondary relief valve 31 through the primary relief valve 5. When the oil pressure output by the primary relief valve 5 exceeds the oil pressure output by the secondary relief valve 31, the oil output by the primary relief valve 5 enters the secondary relief oil circuit 30 through the secondary relief valve 31. Since the second oil inlet 36 connected to the primary relief oil circuit 29 remains closed, the oil inside the primary oil circuit 2 can only enter the first oil inlet 35 of the TC valve 6 through the secondary relief oil circuit 30, and then be output from the second working oil port 40 of the TC valve 6 to the oil inlet of the torque converter 9, then from the oil outlet of the torque converter 9 to the first working oil port 39 of the TC valve 6, and then from the independent oil outlet 37 of the TC valve 6 to the cooling oil circuit 10. Since the hydraulic fluid enters from the inlet of the torque converter 9 and exits from the outlet, the torque converter 9 is in the unlocked state, enabling flexible power transmission between the engine and the transmission. Under this condition, the control solenoid receives no pressure signal feedback to the throttle valve 27, allowing the system to maintain normal oil supply and the oil pump 1 to maintain full power output.

[0050] like Figure 3 As shown, the torque converter 9 is in lock-up condition: When the TC control solenoid valve 7 reverses, the oil outlet of the TC control solenoid valve 7 is connected to the working oil port. At this time, the TC valve 6 begins to change state. The first oil inlet 35 of the TC valve 6 is connected to the independent oil outlet 37, the first working oil port 39 is connected to the third working oil port 41, the second working oil port 40 is connected to the independent pressure relief port 38, and the second oil inlet 36 is connected to the fourth working oil port 42.

[0051] When the oil pressure output by the primary relief valve 5 does not exceed the set pressure of the secondary relief valve 31, the oil inside the primary oil circuit 2 can only enter the TC valve 6 through the primary relief oil circuit 29. At this time, the oil inside the primary relief oil circuit 29 enters through the second inlet 36 and then exits through the fourth working port 42 to the connecting oil circuit 43. A portion of the oil inside the connecting oil circuit 43 enters the second control port 34 at the right end of the TC valve 6, and another portion of the oil inside the connecting oil circuit 43 enters through the third working port 41 of the TC valve 6 and then exits through the first working port 39 to the outlet of the torque converter 9. The inlet of the torque converter 9 is directly connected to the independent pressure relief port 38 of the TC valve 6 through the second working port 40 of the TC valve 6. Since the oil enters from the outlet of the torque converter 9, the torque converter 9 is in a locked state to improve transmission efficiency. At this time, the TC control solenoid valve 7 feeds back the pressure to the throttle valve 27 connected to the first-stage oil circuit 2, opens the oil drain channel, and allows part of the oil output by the oil pump 1 to be directly discharged, reducing the load and power loss of the oil pump 1 and achieving system energy saving.

[0052] When the oil pressure output by the first-stage relief valve 5 exceeds the set pressure of the second-stage relief valve 31, the oil output by the first-stage relief valve 5 enters the second-stage relief oil circuit 30 through the second-stage relief valve 31. The oil inside the second-stage relief oil circuit 30 enters through the first oil inlet 35 and is directly output to the cooling oil circuit 10 from the independent oil outlet 37.

[0053] The two-stage relief valve 31 ensures that oil is preferentially supplied to the hydraulic torque converter 9, and excess oil overflows to the rear end for system cooling and lubrication, which can ensure the overall stability and response speed of the system.

[0054] The three-stage relief valve 32 can ensure that the working pressure of the hydraulic torque converter 9 is within the allowable range, thus avoiding permanent damage to the hydraulic torque converter 9 caused by high system pressure.

[0055] When the cooling system is under normal operating conditions: The oil entering the cooling oil circuit 10 flows into the cooler 44 for cooling. After cooling, it flows through the filter press 45 for filtration and is finally supplied to the lubrication oil circuit 46. The lubrication oil circuit 46, after being cooled and filtered, enters each lubrication point of the automatic transmission hydraulic system to lubricate the components at the lubrication points. After lubrication, it flows back to the oil pan.

[0056] When the cooling system is under high pressure: When the oil viscosity is high or the resistance of the cooler 44 is too great, causing the pressure in the cooling oil circuit 10 to rise to a set value, the cooling bypass valve 48 is opened. At this time, the oil is divided into two paths: one part of the oil continues to flow through the cooler 44 for cooling. The other part of the high-pressure oil flows directly into the lubrication oil circuit 46 through the newly opened cooling bypass valve 48 and the cooling bypass circuit 47. Under high-pressure conditions, without the cooling bypass valve 48, the pressure in the cooling oil circuit 10 would continue to rise, triggering the opening of the cooling safety valve and directly draining the excess high-pressure oil back to the oil pan, resulting in energy waste. By setting the cooling bypass valve 48, this part of the "about to be wasted" high-pressure oil is guided to various lubrication points such as gears and bearings for utilization, instead of being allowed to reach higher pressures and be ineffectively discharged through the cooling safety valve. Through this "pressure-stage utilization" design, the high-pressure oil that is discharged as "waste energy" in the traditional system is successfully transformed into useful lubricating power, achieving efficient recovery of hydraulic energy.

[0057] Since the connection end of the accumulator 49 is connected to the control end of the throttle valve 27, the oil pressure of the cooling and lubrication end is fed back to the throttle valve 27. When there is too much oil at the back end of the system, the pressure is released directly from the front end through the throttle valve 27 by regulating the first outlet of the oil pump 1, thereby improving the system efficiency.

[0058] When the manual shift valve 11 is adjusted to D gear: The clutch solenoid valve 12 is connected to the clutch 13, and the direct oil passage 24 is connected to the reverse gear lock 23. In this way, the reverse gear lock 23 is supplied with oil through the direct oil passage 24 and the manual shift valve 11, so that the third shift fork drive valve 22 cannot be switched to R gear. That is, when the manual shift valve 11 is in D gear, it cannot be switched to R gear.

[0059] When adjusting to first or second gear, firstly, the first gear selection solenoid valve 18 is turned on, and the second gear selection solenoid valve 19 is turned off. This allows the oil from the secondary oil circuit 4 to enter the control interface of the first directional valve 16 via the first gear selection solenoid valve 18, causing the first directional valve 16 to enter the switching state. Since the oil from the secondary oil circuit 4 cannot enter the control interface of the second directional valve 17 via the turned-off second gear selection solenoid valve 19, the second directional valve 17 remains in its initial state. At this time, both interfaces on the first directional valve 16 connected to the second directional valve 17 are directly connected to the two pressure relief ports on the first directional valve 16.

[0060] like Figure 4As shown, when it is necessary to adjust to first gear, the first shift solenoid valve 14 is turned on and the second shift solenoid valve 15 is turned off. In this way, the oil in the first-stage oil circuit 2 enters the first directional valve 16 through the first shift solenoid valve 14, and then flows into the first end of the first shift fork drive valve 20, pushing the first shift fork drive valve 20 to move. The oil at the second end of the first shift fork drive valve 20 passes through the first directional valve 16 and finally flows back to the oil tank from the second shift solenoid valve 15.

[0061] like Figure 5 As shown, when it is necessary to adjust to second gear, the first shift solenoid valve 14 is disconnected and the second shift solenoid valve 15 is connected. In this way, the oil in the first-stage oil circuit 2 enters the first directional valve 16 through the second shift solenoid valve 15, and then flows into the second end of the first shift fork drive valve 20, pushing the first shift fork drive valve 20 to move. The oil at the first end of the first shift fork drive valve 20 passes through the first directional valve 16 and finally flows back to the oil tank from the first shift solenoid valve 14.

[0062] The first shift solenoid valve 14 and the first gear selection solenoid valve 18 are set to normally open, and the second shift solenoid valve 15 and the second gear selection solenoid valve 19 are set to normally closed. In this way, when the hydraulic system control unit of the transmission is damaged, it will automatically engage first gear and realize limp mode.

[0063] When adjusting to third or fourth gear, first disconnect the first gear selection solenoid valve 18 and connect the second gear selection solenoid valve 19. This allows the oil from the secondary oil circuit 4 to enter the control interface of the second directional valve 17 via the second gear selection solenoid valve 19, causing the second directional valve 17 to enter the switching state. Since the oil from the secondary oil circuit 4 cannot pass through the disconnected first gear selection solenoid valve 18 to enter the control interface of the first directional valve 16, the first directional valve 16 remains in its initial state. At this time, the two ports on the first directional valve 16 connected to the second directional valve 17 are respectively connected to the first gear selection solenoid valve 14 and the second gear selection solenoid valve 15. The two ports on the second directional valve 17 connected to the first directional valve 16 are respectively connected to both ends of the second shift fork drive valve 21.

[0064] like Figure 6 As shown, when it is necessary to adjust to the third gear, the first shift solenoid valve 14 is turned on and the second shift solenoid valve 15 is turned off. In this way, the oil in the first-stage oil circuit 2 flows into the first end of the second shift fork drive valve 21 through the first shift solenoid valve 14, the first reversing valve 16, and the second reversing valve 17, pushing the second shift fork drive valve 21 to move. The oil at the second end of the second shift fork drive valve 21 flows into the second reversing valve 17 and the first reversing valve 16 in sequence, and finally flows back to the oil tank from the second shift solenoid valve 15.

[0065] like Figure 7As shown, when it is necessary to adjust to fourth gear, the first shift solenoid valve 14 is disconnected and the second shift solenoid valve 15 is connected. In this way, the oil in the secondary oil circuit 4 flows through the second shift solenoid valve 15, the first reversing valve 16, and the second reversing valve 17 in sequence to the second end of the second shift fork drive valve 21, which pushes the second shift fork drive valve 21 to move. The oil at the first end of the second shift fork drive valve 21 flows through the second reversing valve 17 and the first reversing valve 16 in sequence, and finally flows back to the oil tank from the first shift solenoid valve 14.

[0066] When adjusting to five gears, first disconnect both the first gear selection solenoid valve 18 and the second gear selection solenoid valve 19, so that both the first reversing valve 16 and the second reversing valve 17 are in their initial state. At this time, the two ports on the first reversing valve 16 that are connected to the second reversing valve 17 are respectively connected to the first reversing solenoid valve 14 and the second reversing solenoid valve 15, and the two ports on the second reversing valve 17 that are connected to the first reversing valve 16 are respectively connected to the two ends of the third shift fork drive valve 22.

[0067] like Figure 8 As shown, when it is necessary to adjust to the fifth gear, the first shift solenoid valve 14 is turned on and the second shift solenoid valve 15 is turned off. In this way, the oil in the first-stage oil circuit 2 flows into the first end of the third shift fork drive valve 22 through the first shift solenoid valve 14, the first reversing valve 16, and the second reversing valve 17, pushing the third shift fork drive valve 22 to move. The oil at the second end of the third shift fork drive valve 22 flows into the second reversing valve 17 and the first reversing valve 16, and finally flows back to the oil tank from the second shift solenoid valve 15.

[0068] Since the direct oil circuit 24 is connected to the reverse gear lock 23 at this time, when the vehicle is in D gear, the hydraulic oil pushes out the reverse gear lock 23 valve to realize the reverse gear locking function and protect the vehicle from being mistakenly shifted into R gear when in D gear.

[0069] When the manual shift valve 11 is adjusted to the neutral (N) position: like Figure 9 As shown, both clutch 13 and reverse gear lock 23 are connected to the pressure relief port on manual shift valve 11, cutting off the oil supply to clutch 13 and ensuring absolute system safety. The interfaces connecting clutch solenoid valve 12 and direct oil passage 24 to manual shift valve 11 remain closed. At this time, first shift solenoid valve 14, second shift solenoid valve 15, first gear selection solenoid valve 18, and second gear selection solenoid valve 19 are all in the open state.

[0070] When the manual shift valve 11 is adjusted to the reverse gear: like Figure 10As shown, clutch solenoid valve 12 is connected to clutch 13, reverse gear lock 23 is connected to the pressure relief port of manual shift valve 11, and the interface connecting the direct oil passage 24 to manual shift valve 11 remains closed. This unlocks reverse gear lock 23, disengaging both the first gear selection solenoid valve 18 and the second gear selection solenoid valve 19, thus placing both the first directional valve 16 and the second directional valve 17 in their initial states. At this time, the two interfaces on the first directional valve 16 connected to the second directional valve 17 are respectively connected to the first shift solenoid valve 14 and the second shift solenoid valve 15, and the two interfaces on the second directional valve 17 connected to the first directional valve 16 are respectively connected to both ends of the third shift fork drive valve 22. When it is necessary to adjust to R gear, the first shift solenoid valve 14 is disconnected and the second shift solenoid valve 15 is turned on. In this way, the oil in the first-stage oil circuit 2 flows through the second shift solenoid valve 15, the first reversing valve 16, and the second reversing valve 17 in sequence to the second end of the third shift fork drive valve 22, which pushes the third shift fork drive valve 22 to move. The oil at the first end of the third shift fork drive valve 22 flows through the second reversing valve 17 and the first reversing valve 16 in sequence, and finally flows back to the oil tank from the first shift solenoid valve 14.

[0071] The oil in the first shift solenoid valve 14 and the second shift solenoid valve 15, after being regulated by the first reversing valve 16 and the second reversing valve 17, can selectively flow into one of the two ends of the first shift fork drive valve 20, the second shift fork drive valve 21, and the third shift fork drive valve 22. When the first shift solenoid valve 14 or the second shift solenoid valve 15 supplies oil to one side, it can push the corresponding shift fork drive valve to move to the other side, and the shift fork connected to the gearbox realizes the shifting operation. The three shift fork drive valves can control a total of six gears.

[0072] The present invention can control more sets of shift fork drive valves by increasing the number of similar solenoid valves of the first shift solenoid valve 14 or by increasing the number of directional valve groups, thereby achieving the purpose of controlling more gears.

[0073] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A hydraulic system for an automatic transmission, characterized in that: The system includes an oil pump (1), a TC valve (6), a hydraulic torque converter (9), a clutch (13), a manual shift valve (11), a first shift fork drive valve (20), a second shift fork drive valve (21), a third shift fork drive valve (22), a first directional valve (16), and a second directional valve (17). A primary oil circuit (2) is connected to the outlet of the oil pump (1). A secondary oil circuit (4) is connected to the primary oil circuit (2) via a solenoid oil supply valve (3). A primary relief valve (5) is connected to the primary oil circuit (2). The primary relief valve (5) is connected to the TC valve (6) via the relief oil circuit. A TC control solenoid valve (7) is connected to the secondary oil circuit (4). The TC control solenoid valve (7) is connected to the TC valve (6) via a control oil circuit (8). The TC valve (6) is connected to the hydraulic torque converter (9). A cooling oil circuit (10) is connected to the TC valve (6). A clutch is connected between the primary oil circuit (2) and the manual shift valve (11). The clutch (13) is connected to the manual shift valve (11) and the solenoid valve (12). The first shift solenoid valve (14) and the second shift solenoid valve (15) are connected between the first oil circuit (2) and the first directional valve (16). The first gear selection solenoid valve (18) is connected between the second oil circuit (4) and the first directional valve (16). The second gear selection solenoid valve (19) is connected between the second oil circuit (4) and the second directional valve (17). 7) Connected to the first directional valve (16), the first shift fork drive valve (20) is connected to the first directional valve (16), the second shift fork drive valve (21) and the third shift fork drive valve (22) are connected to the second directional valve (17), the third shift fork drive valve (22) is provided with a reverse gear lock (23), the reverse gear lock (23) is connected to the manual shift valve (11), and the manual shift valve (11) is connected to the first-stage oil circuit (2) through the direct oil circuit (24).

2. A hydraulic system for an automatic transmission according to claim 1, characterized in that: The oil pump (1) is a dual-outlet oil pump (1), and the two outlets of the oil pump (1) are all connected to the primary oil circuit (2); the oil inlet of the oil pump (1) is connected to the suction filter (25), and the inlet of the suction filter (25) is connected to the oil tank; a check valve (26) is provided at the first outlet of the oil pump (1); a throttle valve (27) is connected to the first outlet of the oil pump (1) through the oil circuit, and a system safety valve (28) is provided in parallel between the oil inlet and the outlet of the oil pump (1); the drain port of the throttle valve (27) and the drain port of the system safety valve (28) are both connected to the oil inlet of the oil pump (1).

3. A hydraulic system for an automatic transmission according to claim 2, characterized in that: The overflow oil circuit includes a primary overflow oil circuit (29) and a secondary overflow oil circuit (30). The primary overflow oil circuit (29) and the secondary overflow oil circuit (30) are connected in parallel at the outlet of the primary overflow valve (5). A secondary overflow valve (31) is installed on the secondary overflow oil circuit (30). A tertiary overflow valve (32) is connected to the secondary overflow oil circuit (30) through an oil circuit.

4. A hydraulic system for an automatic transmission according to claim 3, characterized in that: The TC valve (6) has a first control port (33) and a second control port (34) at both ends. The TC valve has two inlets, one independent outlet (37), four working ports, and one independent pressure relief port (38). The first inlet (35) of the TC valve (6) is connected to the secondary overflow circuit (30), the second inlet (36) of the TC valve (6) is connected to the primary overflow circuit (29), and the independent outlet (38) of the TC valve (6) has two inlets, one independent outlet (37), four working ports, and one independent pressure relief port (38). 7) Connected to the cooling oil circuit (10), the first working oil port (39) of the TC valve (6) is connected to the oil outlet of the hydraulic torque converter (9), the second working oil port (40) of the TC valve (6) is connected to the oil inlet of the hydraulic torque converter (9), the third oil port of the TC valve (6) is connected to the second control port (34) on the right side of the TC valve (6) through the connecting oil circuit (43), and the fourth working oil port (42) of the TC valve (6) is connected to the connecting oil circuit (43).

5. A hydraulic system for an automatic transmission according to claim 4, characterized in that: The electromagnetic TC valve (6) is provided with a pressure feedback port, an oil inlet, an oil outlet, and a working oil port. The pressure feedback port is located at one end of the return spring of the electromagnetic TC valve (6). The pressure feedback port is connected to the working oil port. The oil inlet of the TC control solenoid valve (7) is connected to the first-stage oil circuit (2). The working oil port of the TC control solenoid valve (7) is connected to the first control port (33) on the left side of the TC valve (6). The oil outlet of the TC control solenoid valve (7) is connected to the oil tank. The pressure feedback port of the TC control solenoid valve (7) is connected to the control end of the throttle valve (27).

6. A hydraulic system for an automatic transmission according to claim 1, characterized in that: A cooler (44) and a filter press (45) are sequentially installed on the cooling oil circuit (10). A lubricating oil circuit (46) is installed at the outlet end of the cooling oil circuit (10). The lubricating oil circuit (46) is connected to each lubrication point of the automatic transmission hydraulic system. A cooling bypass circuit (47) is installed in parallel on the cooling oil circuit (10). A cooling bypass valve (48) is installed on the cooling bypass circuit (47).

7. A hydraulic system for an automatic transmission according to claim 1, characterized in that: The manual shift valve (11) is provided with two pressure relief ports and four interfaces, the four interfaces being connected to the clutch solenoid valve (12), clutch (13), reverse gear lock (23), and straight-through oil circuit (24), respectively.

8. A hydraulic system for an automatic transmission according to claim 1, characterized in that: The first shift fork drive valve (20) is a 1 / 2 gear shift fork drive valve, the second shift fork drive valve (21) is a 3 / 4 gear shift fork drive valve, and the third shift fork drive valve (22) is a 5 / R gear shift fork drive valve.

9. A hydraulic system for an automatic transmission according to claim 1, characterized in that: Both the first reversing valve (16) and the second reversing valve (17) are provided with six ports and three pressure relief ports. A control port is provided at the end of both the first reversing valve (16) and the second reversing valve (17) furthest from the return spring. The first and second ports on the first reversing valve (16) are connected to the first shift solenoid valve (14) and the second shift solenoid valve (15), respectively. The control port on the first reversing valve (16) is connected to the first gear selection solenoid valve (18). The third and fourth ports on the first reversing valve (16)... The interfaces on the first directional valve (16) are connected to the interfaces at both ends of the first directional valve (20); the fifth and sixth interfaces on the first directional valve (16) are connected to the first and second interfaces on the second directional valve (17); the third and fourth interfaces on the second directional valve (17) are connected to the two ends of the second directional valve (21); the fifth and sixth interfaces on the second directional valve (17) are connected to the two ends of the third directional valve (22); and the control interface of the second directional valve (17) is connected to the second gear selection solenoid valve (19).

10. A hydraulic system for an automatic transmission according to claim 9, characterized in that: The first shift solenoid valve (14), the second shift solenoid valve (15), the first gear selection solenoid valve (18), and the second gear selection solenoid valve (19) are all two-position three-way valves; the first shift solenoid valve (14) and the first gear selection solenoid valve (18) are normally open, and the second shift solenoid valve (15) and the second gear selection solenoid valve (19) are normally closed.

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