CN117515147A - 8AT automatic transmission hydraulic system - Google Patents

Abstract

The invention discloses an 8AT automatic transmission hydraulic system which comprises a first pressure regulating valve, a second pressure regulating valve, a first switching valve, a main oil way, a first electromagnetic valve, a second electromagnetic valve, a third electromagnetic valve, a fourth electromagnetic valve, a fifth electromagnetic valve and a sixth electromagnetic valve, wherein the first electromagnetic valve and the fifth electromagnetic valve are connected with an advance gear oil way, the sixth electromagnetic valve is connected with the main oil way, the second electromagnetic valve and the fourth electromagnetic valve are connected with a decompression oil way, the first electromagnetic valve, the fifth electromagnetic valve, the third electromagnetic valve and the sixth electromagnetic valve are direct-drive electromagnetic valves, and the second electromagnetic valve and the fourth electromagnetic valve are pilot electromagnetic valves. According to the 8AT automatic transmission hydraulic system, the control of each clutch of the transmission is realized by adopting the direct-drive electromagnetic valve and the pilot electromagnetic valve, the failure mode of the clutch is realized by utilizing the two normally-high pilot electromagnetic valves, the design of the pressure regulating valve core is simplified, the structure is simple, the design is compact, the cost advantage is realized, and the occupied space is reduced.

Description

8AT automatic transmission hydraulic system

Technical field

The invention belongs to the technical field of automatic transmissions, and specifically relates to an 8AT automatic transmission hydraulic system.

Background technique

8AT automatic transmission refers to an automatic transmission with 8 forward gears.

In related technologies, pilot solenoid valves and pressure regulating valves are often used in 8AT automatic transmission hydraulic systems for pressure control and regulation, and switch valves are used to realize the failure mode of the transmission. The structure is complex and the cost is high.

For example, the patent document with publication number CN107975594A discloses a hydraulic system of an automatic transmission, including a first failure valve, a second failure valve connected to the first failure valve, a normal high solenoid valve for controlling the first failure valve, and The first failover valve connects the clutch system and the normally low solenoid valve for controlling the second failover valve and for forming two failover gears.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an 8AT automatic transmission hydraulic system with the purpose of improving the compactness of the structure.

In order to achieve the above object, the technical solution adopted by the present invention is: an 8AT automatic transmission hydraulic system, including a first pressure regulating valve, a second pressure regulating valve, a first switching valve, a main oil circuit, a first solenoid valve, and a second solenoid valve. , the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve, the sixth solenoid valve and the main pressure regulating valve. The first solenoid valve and the fifth solenoid valve are connected to the forward oil line, and the sixth solenoid valve is connected to the main oil line. connection, the second solenoid valve and the fourth solenoid valve are connected to the pressure reducing oil line, the first solenoid valve, the fifth solenoid valve, the third solenoid valve and the sixth solenoid valve are direct drive solenoid valves, the second solenoid valve and the fourth solenoid valve are The solenoid valve is a pilot solenoid valve. The first pressure regulating valve is connected to the forward oil line and the C2 clutch of the 8AT automatic transmission. The third solenoid valve is connected to the C3 clutch of the 8AT automatic transmission. The second pressure regulating valve is connected to the forward oil line and The C4 clutch of the 8AT automatic transmission is connected. The first switching valve is connected to the first solenoid valve and the start-stop oil line. The start-stop oil line is set to provide an oil source for the C1 clutch.

The pressure reducing oil circuit is connected to the lock prohibition valve, the TC solenoid valve is connected to the lock prohibition valve, the shuttle valve is connected to the forward oil circuit and the reverse oil circuit, and the third solenoid valve is connected to the shuttle valve.

The shuttle valve has a first oil inlet, a second oil inlet and an oil outlet. The first oil inlet of the shuttle valve is connected to the forward gear oil path, and the second oil inlet of the shuttle valve is connected to the reverse gear. The oil circuit is connected, and the oil outlet of the shuttle valve is connected with the oil inlet of the third solenoid valve.

The oil inlet of the first pressure regulating valve is connected to the forward oil passage, and the oil outlet of the first pressure regulating valve is connected to the C2 clutch.

The oil inlet of the second pressure regulating valve is connected to the forward oil passage, and the oil outlet of the second pressure regulating valve is connected to the C4 clutch.

The start-stop oil circuit includes a start-stop pump, the first switching valve has a first oil inlet and a second oil inlet, and the first oil inlet of the first switching valve is connected with the oil outlet of the first solenoid valve. The second oil inlet of the first switching valve is connected with the oil outlet of the start-stop pump.

The pressure reducing oil circuit includes a pressure reducing valve, the pressure reducing oil circuit includes an oil inlet of the pressure reducing valve connected to the main oil circuit, an oil outlet of the pressure reducing valve connected to the second solenoid valve and the The fourth solenoid valve connection.

The main pressure regulating valve is connected to the P2 oil circuit, and the P2 oil circuit is set to supply oil to the cooling lubricating oil circuit. The cooling lubricating oil circuit includes a cooling pressure regulating valve and an oil cooler. The cooling pressure regulating valve is connected to the PL solenoid valve, and the PL solenoid valve The valve is connected to the main pressure regulating valve and the pressure reducing oil circuit, and the PL solenoid valve is a pilot solenoid valve.

The 8AT automatic transmission hydraulic system also includes a first pressure maintaining valve, a second pressure maintaining valve, a third pressure maintaining valve, a fourth pressure maintaining valve, a fifth pressure maintaining valve, a sixth pressure maintaining valve and a seventh pressure maintaining valve. valve, the first pressure maintaining valve is located on the first solenoid valve unloading oil path, the second pressure maintaining valve and the third pressure maintaining valve are located on the C2 clutch unloading oil path, the fourth pressure maintaining valve and the fifth pressure maintaining valve are located on the C2 clutch oil unloading oil path. The valve is located on the C4 clutch oil unloading oil path, the sixth pressure maintaining valve is located on the oil unloading oil path of the sixth solenoid valve, the seventh pressure maintaining valve is located between the shuttle valve and the manual valve, and the seventh pressure maintaining valve is set to Used to maintain pressure when unloading oil in the forward oil passage.

The 8AT automatic transmission hydraulic system also includes a first accumulator, a second accumulator, a third accumulator, a fourth accumulator, a fifth accumulator, a sixth accumulator and a seventh accumulator. The first accumulator is located in the C1 clutch oil circuit and is used to buffer the pressure fluctuations of the C1 clutch oil circuit. The second accumulator is located in the B1 clutch oil circuit and is used to buffer the pressure fluctuations of the B1 clutch oil circuit. The third accumulator is located in The B2 clutch oil circuit is used to buffer the pressure fluctuation of the B2 clutch oil circuit. The fourth accumulator is located in the C3 clutch oil circuit and is used to buffer the pressure fluctuation of the C3 clutch oil circuit. The fifth accumulator is located at the outlet of the second solenoid valve. between the oil port and the first pressure regulating valve and used to buffer the pressure fluctuation of the C2 clutch oil circuit; the sixth accumulator is located between the oil outlet of the fourth solenoid valve and the second pressure regulating valve; It is used to buffer the C4 clutch oil circuit pressure fluctuation. The seventh accumulator is located between the oil outlet of the PL solenoid valve and the main pressure regulating valve and is used to buffer the main oil circuit pressure fluctuation.

The 8AT automatic transmission hydraulic system of the present invention uses a direct drive solenoid valve and a pilot solenoid valve to control each clutch of the transmission, uses two normally high pilot solenoid valves to realize the failure mode of the clutch, simplifies the design of the pressure regulating valve core, and has a simple structure and design Compact, cost-effective and reduces space requirements.

Description of drawings

This manual includes the following drawings, which show:

Figure 1 is a schematic structural diagram of the 8AT automatic transmission hydraulic system of the present invention;

Marked in the picture are:

1. Oil pump; 2. Filter; 3. Electromagnetic pump; 4. First switching valve; 5. First accumulator; 6. First solenoid valve; 7. First pressure maintaining valve; 8. Fifth solenoid valve; 9. Fifth accumulator; 10. First pressure regulating valve; 11. Second solenoid valve; 12. Second pressure regulating valve; 13. Fourth solenoid valve; 14. Cooling pressure regulating valve; 15. Oil Cooler; 16. Cooling back pressure valve; 17. One-way valve; 18. Cooling safety valve; 19. TC lock valve; 20. TC release valve; 21. TC solenoid valve; 22. Sixth solenoid valve; 23. The third solenoid valve; 24. Shuttle valve; 25. Manual valve; 26. Main pressure regulating valve; 27. First filter; 28. Main oil line safety valve; 29. Pressure reducing valve; 30. Lock-up prohibition valve;

31. PL solenoid valve; 32. Forward oil circuit; 33. Main oil circuit; 34. P2 oil circuit; 35. Decompression oil circuit; 36. Cooling lubricating oil circuit; 37. Pilot oil circuit; 38. Reverse oil circuit 39. Start-stop oil circuit; 40. Second pressure maintaining valve; 41. Third pressure maintaining valve; 42. Fourth pressure maintaining valve; 43. Fifth pressure maintaining valve; 44. Sixth pressure maintaining valve; 45 , the seventh pressure maintaining valve; 46. the second accumulator; 47. the third accumulator; 48. the fourth accumulator; 49. the sixth accumulator; 50. TC pressure maintaining valve; 51. the second Filter; 52. Pressure sensor; 53. Oil temperature sensor; 54. Seventh accumulator; 55. STC oil circuit.

Detailed ways

The specific implementation modes of the present invention will be further described in detail below by describing the embodiments with reference to the accompanying drawings. The purpose is to help those skilled in the art have a more complete, accurate and in-depth understanding of the concepts and technical solutions of the present invention, and contribute to its implementation.

It should be noted that in the following embodiments, the "first", "second", "third", "fourth", "fifth", "sixth" and "seventh" are not used together. It does not represent an absolute distinction in structure and/or function, nor does it represent an order of execution, but is merely for the convenience of description.

As shown in Figure 1, the present invention provides an 8AT automatic transmission hydraulic system, including an oil pump 1, a start-stop pump 3, a main pressure regulating valve 26 connected to the oil pump 3, a forward oil path 32 connected to a manual valve 25, The main oil line 33 connected to the main pressure regulating valve 26, the P2 oil line 34 connected to the main pressure regulating valve 26, the pressure reducing oil line 35 connected to the pressure reducing valve 29, the TC lock valve 19 and the TC release valve 20 The cooling lubricating oil passage 36 is connected, the pilot oil passage 37 is connected to the PL solenoid valve 31 , the reverse oil passage 38 is connected to the manual valve 25 , and the start-stop oil passage 39 is connected to the start-stop pump 3 .

Specifically, as shown in Figure 1, the oil pump 1 is a gear pump, the first solenoid valve 6, the fifth solenoid valve 8, the third solenoid valve 23, and the sixth solenoid valve 22 are direct drive solenoid valves, and the second solenoid valve 11 The fourth solenoid valve 13, TC solenoid valve 21, and PL solenoid valve 31 are pilot solenoid valves. The first solenoid valve 6 and the fifth solenoid valve 8 are connected to the forward oil passage 32, and the sixth solenoid valve 22 is connected to the main oil passage 33. connection, the second solenoid valve 11, the fourth solenoid valve 13, the PL solenoid valve 31 are connected to the pressure reducing oil line 35, the lock prohibition valve 30 is connected to the pressure reducing oil line 35, the TC solenoid valve 21 is connected to the lock prohibition valve 30 , the shuttle valve 24 is connected to the forward oil passage 32 and the reverse oil passage 38, and the third solenoid valve is connected to the shuttle valve 24. By adjusting the corresponding solenoid valve, the corresponding clutch combination and release inside the transmission can be controlled to realize the commands of forward gear 1 to 8 of the transmission as well as parking, neutral, and reverse gear.

As shown in Figure 1, the oil inlet of the first pressure regulating valve 10 is connected to the forward oil passage 32, and the oil outlet of the first pressure regulating valve 10 is connected to the C2 clutch of the 8AT automatic transmission. The oil inlet of the second pressure regulating valve 12 is connected to the forward oil passage 32, and the oil outlet of the second pressure regulating valve 12 is connected to the C4 clutch of the 8AT automatic transmission.

As shown in Figure 1, the first switching valve 4 has a first oil inlet, a second oil inlet, a control port and an oil outlet. The first oil inlet of the first switching valve 4 is connected with the first solenoid valve 6 The oil outlet is connected, and the second oil inlet of the first switching valve 4 is connected with the oil outlet of the start-stop pump 3 through the start-stop oil line.

As shown in FIG. 1 , the oil inlet of the pressure reducing valve 29 is connected to the main oil line 33 , and the oil outlet of the pressure reducing valve 29 is connected to the pressure reducing oil line 35 .

As shown in Figure 1, the shuttle valve 24 has a first oil inlet, a second oil inlet and an oil outlet. The first oil inlet of the shuttle valve 24 is connected to the forward oil passage 32, and the second oil inlet of the shuttle valve 24 is connected to the forward oil passage 32. The oil inlet is connected to the reverse oil passage 38 , and the oil outlet of the shuttle valve 24 is connected to the oil inlet of the third solenoid valve 23 .

As shown in FIG. 1 , the oil inlet of the cooling pressure regulating valve 14 is connected to the cooling lubricating oil passage 36 , and the oil outlet of the cooling pressure regulating valve 14 is connected to the oil cooler 15 .

As shown in FIG. 1 , the oil inlet of the lockup prohibition valve 30 is connected to the pressure reducing oil line 35 , and the oil outlet of the lockup prohibition valve 30 is connected to the oil inlet of the TC solenoid valve 21 . The oil inlet of the TC lock-up valve 19 is connected to the main oil line 33, and the oil outlet of the TC lock-up valve 19 is connected to the TC coupling end (the coupling end of the hydraulic pitch converter). The oil inlet of the TC release valve 20 is connected to the P2 oil line 34, and the oil outlet of the TC release valve 20 is connected to the TC release end.

As shown in Figure 1, when the transmission is in D gear, the manual valve 25 is in the leftmost position, the main oil path 33 is connected to the forward oil path 32, and the forward oil path 32 is connected to the oil inlet of the first solenoid valve 6 , the oil inlet of the fifth solenoid valve 8, the oil inlet of the first pressure regulating valve 10, the oil inlet of the second pressure regulating valve 12, the first oil inlet of the shuttle valve 24, the forward oil passage 32 will shuttle The steel ball inside the valve 24 is pushed to the right end. At this time, the forward oil passage 32 can communicate with the oil inlet of the third solenoid valve 23 through the shuttle valve 24. After being regulated by the main pressure regulating valve 26, the main oil line 33 enters the first filter 27 and the second filter 51, and is connected to the oil inlet of the pressure reducing valve 29. The oil outlet of the pressure reducing valve 29 is connected to the fourth solenoid. Valve 13.

The main oil line 33 passes through the rightmost control port of the main pressure regulating valve 26, pushing the valve core of the main pressure regulating valve 26 to the right, and the main oil line 33 is connected to the P2 oil line 34. The rightmost end of the valve core of the main pressure regulating valve 26 is connected to the pilot oil line 37. The pressure of the main oil line 33 at the leftmost end of the main pressure regulating valve 26, the spring force at the rightmost end of the valve core, and the pressure of the pilot oil line 37 Maintaining balance under the action of the three forces, by adjusting the current of the PL solenoid valve 31, the pressure of the pilot oil line 37 is controlled to achieve the purpose of adjusting the oil pressure of the main oil line 33. The pressure range of the main oil line 33 is set at 0~18.3bar. , the pressure sensor 52 can monitor the oil pressure of the main oil line 33, and the main oil line 33 is provided with a main oil line safety valve 28 to prevent the system from overloading and working abnormally.

As shown in Figure 1, when the transmission is in D gear, the forward gear oil passage 32 provides oil source to a total of three direct drive solenoid valves: the first solenoid valve 6, the fifth solenoid valve 8, and the third solenoid valve 23. By adjusting the corresponding The current of the solenoid valve can control the oil pressure entering the corresponding clutch.

The pressure reducing oil line 35 provides an oil source to a total of four pilot solenoid valves: the second solenoid valve 11, the third solenoid valve 13, the PL solenoid valve 31, and the TC solenoid valve 21. By adjusting the current of the corresponding solenoid valve, the corresponding clutch can be controlled. oil line pressure. The valve core of the pressure reducing valve 29 maintains balance under the action of the oil pressure of the pressure reducing oil circuit 35 at the far left end of the valve core and the spring force at the right end of the valve core. The pressure reducing valve 29 controls the pressure of the pressure reducing oil circuit 35 at 7.8bar and The following is to adapt to the pressure regulating range of the pilot solenoid valve: 7.8~0bar or 0~7.8bar. The main oil line 33 provides an oil source to the sixth solenoid valve 22. The sixth solenoid valve 22 is connected to the B2 clutch of the AT automatic transmission. By adjusting the current of the sixth solenoid valve 22, the oil line entering the B2 clutch of the AT automatic transmission can be controlled. pressure.

As shown in Figure 1, the first accumulator 5 is located in the C1 clutch oil circuit. The first accumulator 5 is used to buffer the pressure fluctuation of the C1 clutch oil circuit. The C1 clutch oil circuit is connected to the C1 clutch. The second accumulator 46 is located in the B1 clutch oil circuit and is used to buffer the pressure fluctuation of the B1 clutch oil circuit. The B1 clutch oil circuit is connected to the B1 clutch. The third accumulator 47 is located in the B2 clutch oil circuit and is used to buffer the pressure fluctuation of the B2 clutch oil circuit. The B2 clutch oil circuit is connected to the B2 clutch. The fourth accumulator 48 is located in the C3 clutch oil circuit and is used to buffer the pressure fluctuation of the C3 clutch oil circuit. The C3 clutch oil circuit is connected to the C3 clutch. The fifth accumulator 9 is located between the oil outlet of the second solenoid valve 11 and the first pressure regulating valve 10, and is used to buffer the pressure fluctuation of the C2 clutch oil circuit, which is connected to the C2 clutch. The sixth accumulator 49 is located between the oil outlet of the fourth solenoid valve 13 and the second pressure regulating valve 12, and is used to buffer the pressure fluctuation of the C4 clutch oil circuit, which is connected to the C4 clutch. The seventh accumulator 54 is located between the oil outlet of the PL solenoid valve 31 and the main pressure regulating valve 26, and is used to buffer pressure fluctuations in the main oil line. The function of the pressure maintaining valve is to keep the oil circuit always filled with oil and increase the response speed of the system.

As shown in Figure 1, the first pressure maintaining valve 7 is located on the oil unloading oil path of the first solenoid valve 6, the second pressure maintaining valve 40 and the third pressure maintaining valve 41 are located on the C2 clutch oil unloading oil path, and the fourth pressure maintaining valve 42 and the fifth pressure maintaining valve 43 are located on the C4 clutch unloading oil path, the sixth pressure maintaining valve 44 is located on the unloading oil path of the sixth solenoid valve 22, and the seventh pressure maintaining valve 45 is located between the shuttle valve 24 and the manual valve 25 , the seventh pressure maintaining valve is used to maintain pressure in the forward oil blocking passage 32 when unloading oil.

As shown in Figure 1, the cooling lubricating oil circuit 36 is provided with a cooling safety valve 18. The cooling safety valve 18 is used to control the maximum pressure of the cooling lubricating oil circuit 36 to protect the normal operation of the system. The cooling lubricating oil circuit 36 enters the oil cooler 15 after being regulated by the cooling pressure regulating valve 14. When the valve core of the cooling pressure regulating valve 14 is at the leftmost end, the pressure of the cooling lubricating oil circuit 36 and the pressure of the pilot oil circuit 37 connected to the rightmost end are When maintaining balance, the pressure of the cooling oil circuit 36 can be controlled by adjusting the current of the PL solenoid valve 31. The cooling lubricating oil path 36 passes through the oil cooler 15 and then enters the front transmission mechanism and the rear transmission mechanism of the transmission. When the oil cooler 15 is blocked, the cooling oil path passes through the bypass oil path and enters the transmission through the one-way valve 16 Front transmission and rear transmission.

As shown in Figure 1, when the TC solenoid valve 21 is de-energized, the P2 oil line 34 is connected to the oil inlet of the TC release valve 20, and the P2 oil line 34 supplies oil to the TC release end. At this time, the TC is in a released state. If there is an area difference between the left and right ends of the oil inlet chamber of the TC release valve 20, the oil inlet chamber of the TC release valve will produce a pressure difference to the right. At this time, the spool of the TC release valve 20 is between the pressure difference in the oil inlet chamber and the rightmost end. maintain balance under the action of the spring force. When the TC solenoid valve 21 is energized, the spool of the TC release valve 20 moves to the right under the pressure of the STC oil line 55, the P2 oil line 34 is disconnected from the rear end oil line of the TC release valve 20, and the TC lock valve 19 The valve core moves to the left under the pressure of STC oil line 55. The main oil line 33 is connected with the oil inlet of TC lock valve 19. The main oil line 33 supplies oil to the TC coupling end. At this time, the TC (hydraulic variable speed changer) Torque device) is in the combined state. The valve core of the TC lock valve 19 maintains balance under the action of the leftmost TC connecting end pressure, spring force and the pressure of the STC oil line 55 on the rightmost side of the valve core.

As shown in Figure 1, when the transmission is in R gear, the manual valve 25 is in the third position on the left, the main oil line 33 is connected to the reverse oil line 38, and the reverse oil line 38 is connected to the second inlet of the shuttle valve 24. The oil port and reverse oil passage 38 push the steel ball inside the shuttle valve 24 to the left end, and the reverse oil passage 38 communicates with the third solenoid valve 23 through the shuttle valve 24. When the sixth solenoid valve 22 is energized, the spool of the lock-up prohibition valve 30 moves to the left under the pressure of the B2 clutch oil circuit, and the decompression oil circuit 35 is disconnected from the oil inlet of the TC solenoid valve 21 to prevent forward movement. When the B2 clutch is engaged in 1st gear, park gear, neutral gear, and reverse gear, TC may be mistakenly engaged.

As shown in Figure 1, when the engine in D gear stalls, the start-stop pump 3 is energized, and the start-stop pump 3 sucks oil from the fuel tank, passes through the filter 2, and enters the start-stop oil circuit 39. The engine stalls and the oil pump 1 does not work. The first There is no pressure in the main oil line 33 at the control port of the switching valve 4. The spool of the first switching valve 4 moves to the right end under the action of the left spring force. At this time, the start-stop oil line 39 is connected to the C1 clutch oil line, and the start-stop Oil line 39 provides an oil source for the C1 clutch, and the C1 clutch is coupled. After the engine is ignited, the main oil line 33 begins to build pressure, the spool of the first switching valve 4 moves to the left, and the oil source of the C1 clutch oil line is switched to the oil outlet of the first solenoid valve 6. The system responds quickly to ensure the forward gear. C1 clutch is engaged.

As shown in Figure 1, the second solenoid valve 12 and the fourth solenoid valve 13 are normally high pilot solenoid valves. When the TCU (automatic transmission control unit) control fails, the second solenoid valve 12 controls the C2 clutch to engage, and the fourth solenoid valve Valve 13 controls the C4 clutch engagement and the transmission enters the 6-speed mode to prevent further damage to the transmission and ensure that the owner can successfully drive the vehicle to a maintenance point for repair.

In this embodiment, the automatic transmission is an 8AT automatic transmission.

The 8AT automatic transmission hydraulic system with the above structure has the following advantages:

(1) It takes full advantage of the simple structure of the direct-drive solenoid valve to control the transmission clutch, cancels the application of on-off solenoid valves, and directly uses the characteristics of the normal high solenoid valve to control the clutch corresponding to the transmission into the failed gear, greatly simplifying the valve body structural design;

(2) Use a pressure maintaining valve to improve the system response speed. The clutch oil line is equipped with an accumulator to buffer the pressure fluctuations in the oil line, making pressure control more stable and improving driving comfort;

(3) While ensuring the function, simplify it as much as possible, reduce the use of a large number of pressure regulating valves and switching slide valves, cancel the use of some pressure regulating valve valve core return springs, simplify the valve core design, compact design, and have cost advantages ;

(4) Simplify the design of the valve body oil circuit and reduce valve body leakage points, which can better provide cooling and lubrication for the planetary gear mechanism of the transmission and protect the normal operation of the transmission.

The present invention has been exemplarily described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above manner. As long as various non-substantive improvements are made using the method concepts and technical solutions of the present invention; or the above-mentioned concepts and technical solutions of the present invention are directly applied to other situations without improvement, they all fall within the protection scope of the present invention. within.

Claims (10)

The 1.8AT automatic transmission hydraulic system is characterized by: including a first pressure regulating valve, a second pressure regulating valve, a first switching valve, a main oil circuit, a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth The solenoid valve, the fifth solenoid valve, the sixth solenoid valve and the main pressure regulating valve, the first solenoid valve and the fifth solenoid valve are connected to the forward oil line, the sixth solenoid valve is connected to the main oil line, the second solenoid valve and the Four solenoid valves are connected to the pressure reducing oil circuit. The first solenoid valve, the fifth solenoid valve, the third solenoid valve and the sixth solenoid valve are direct drive solenoid valves. The second solenoid valve and the fourth solenoid valve are pilot solenoid valves. One pressure regulating valve is connected to the forward oil line and the C2 clutch, the third solenoid valve is connected to the C3 clutch, the second pressure regulating valve is connected to the forward oil line and the C4 clutch, the first switching valve is connected to the first solenoid valve and the start-stop The oil circuit is connected, and the start-stop oil circuit is set to provide oil source for the C1 clutch. 2. The 8AT automatic transmission hydraulic system according to claim 1, characterized in that: the pressure reducing oil circuit is connected to the lock-up prohibition valve, the TC solenoid valve is connected to the lock-up prohibition valve, and the shuttle valve is connected to the forward oil blocking valve. The third solenoid valve is connected to the shuttle valve. 3. The 8AT automatic transmission hydraulic system according to claim 2, characterized in that: the shuttle valve has a first oil inlet, a second oil inlet and an oil outlet, and the first oil inlet of the shuttle valve is connected to the first oil inlet of the shuttle valve. The forward oil passage is connected, the second oil inlet of the shuttle valve is connected to the reverse oil passage, and the oil outlet of the shuttle valve is connected to the oil inlet of the third solenoid valve. 4. The 8AT automatic transmission hydraulic system according to any one of claims 1 to 3, characterized in that: the oil inlet of the first pressure regulating valve is connected to the forward oil passage, and the outlet of the first pressure regulating valve The oil port is connected to the C2 clutch. 5. The 8AT automatic transmission hydraulic system according to any one of claims 1 to 3, characterized in that: the oil inlet of the second pressure regulating valve is connected to the forward oil passage, and the outlet of the second pressure regulating valve The oil port is connected to the C4 clutch. 6. The 8AT automatic transmission hydraulic system according to any one of claims 1 to 3, characterized in that: the start-stop oil circuit includes a start-stop pump, and the first switching valve has a first oil inlet and a second inlet. The oil port, the first oil inlet of the first switching valve is connected to the oil outlet of the first solenoid valve, and the second oil inlet of the first switching valve is connected to the oil outlet of the start-stop pump. 7. The 8AT automatic transmission hydraulic system according to any one of claims 1 to 3, characterized in that: the pressure reducing oil circuit includes a pressure reducing valve, and the pressure reducing oil circuit includes an oil inlet of the pressure reducing valve and the pressure reducing oil circuit. The main oil line is connected, and the oil outlet of the pressure reducing valve is connected with the second solenoid valve and the fourth solenoid valve. 8. The 8AT automatic transmission hydraulic system according to any one of claims 1 to 3, characterized in that: the main pressure regulating valve is connected to the P2 oil circuit, and the P2 oil circuit is configured to supply oil to the cooling lubricating oil circuit, and the cooling lubricating oil is supplied to the cooling lubricating oil circuit. The circuit includes a cooling pressure regulating valve and an oil cooler. The cooling pressure regulating valve is connected to the PL solenoid valve. The PL solenoid valve is connected to the main pressure regulating valve and the pressure reducing oil circuit. The PL solenoid valve is a pilot solenoid valve. 9. The 8AT automatic transmission hydraulic system according to any one of claims 1 to 3, characterized in that: it further includes a first pressure maintaining valve, a second pressure maintaining valve, a third pressure maintaining valve, a fourth pressure maintaining valve, Five pressure maintaining valves, the sixth pressure maintaining valve and the seventh pressure maintaining valve, the first pressure maintaining valve is located on the first solenoid valve unloading oil path, the second pressure maintaining valve and the third pressure maintaining valve are located on the C2 clutch On the oil unloading oil path, the fourth pressure maintaining valve and the fifth pressure maintaining valve are located on the C4 clutch oil unloading oil path, the sixth pressure maintaining valve is located on the oil unloading oil path of the sixth solenoid valve, and the seventh pressure maintaining valve is located on the oil unloading oil path of the sixth solenoid valve. Between the shuttle valve and the manual valve, a seventh pressure maintaining valve is configured to maintain pressure when the forward oil passage is unloading oil. 10. The 8AT automatic transmission hydraulic system according to any one of claims 1 to 3, characterized in that: it further includes a first accumulator, a second accumulator, a third accumulator, a fourth accumulator, and a third accumulator. Five accumulators, the sixth accumulator and the seventh accumulator. The first accumulator is located in the C1 clutch oil circuit and is used to buffer the pressure fluctuation of the C1 clutch oil circuit. The second accumulator is located in the B1 clutch oil circuit and is used to buffer the pressure fluctuation of the C1 clutch oil circuit. To buffer the pressure fluctuations of the B1 clutch oil circuit, the third accumulator is located in the B2 clutch oil circuit and is used to buffer the pressure fluctuations of the B2 clutch oil circuit. The fourth accumulator is located in the C3 clutch oil circuit and is used to buffer the pressure fluctuations of the C3 clutch oil circuit. , the fifth accumulator is located between the oil outlet of the second solenoid valve and the first pressure regulating valve and is used to buffer the C2 clutch oil circuit pressure fluctuation, and the sixth accumulator is located at the fourth solenoid valve The seventh accumulator is located between the oil outlet of the PL solenoid valve and the main pressure regulating valve and is used to buffer the main pressure fluctuation of the C4 clutch oil circuit. Oil line pressure fluctuations.