Automatic transmission hydraulic control system

Abstract

The application discloses an automatic transmission hydraulic control system, comprising a mechanical oil pump, a main pressure regulating valve, a main pressure regulating solenoid valve SPL, a manual valve, a shuttle valve and first and second switching valves. The mechanical oil pump provides pressure oil, and the main pressure regulating valve cooperates with the main pressure regulating solenoid valve SPL to regulate the main oil path PL oil pressure; the manual valve can selectively supply oil to the forward gear oil path PD or the reverse gear oil path PR, and the shuttle valve connects the two oil paths and blocks the non-oil supply oil path; the first switching valve controls the output oil path of at least two clutch solenoid valves, switches to the first position when the set condition is met, and makes the forward gear oil path PD act on the second switching valve; when the main pressure regulating solenoid valve SPL is not powered, the second switching valve switches to the preset position, and the forward gear oil path PD directly provides the combination oil pressure for the predetermined clutch to form the failure gear. The system utilizes the structural advantages of the direct-drive solenoid valve, controls the on-off switching of the oil path through the manual valve and the shuttle valve, avoids the gear position inconsistency caused by the solenoid valve failure, guarantees the driving safety, simplifies the structure and reduces the manufacturing cost.

Description

Technical Field

[0001] This invention belongs to the field of automatic transmission technology, specifically, it relates to an automatic transmission hydraulic control system. Background Technology

[0002] The gear shifting of an automatic transmission is controlled by a hydraulic control system. This system uses solenoid valves to control the engagement or disengagement of hydraulic actuators, thus enabling gear switching. Automatic transmissions typically also have a fail-safe gear to ensure that the transmission can still transmit power in the event of a non-electrical fault, allowing the vehicle to limp to a repair shop.

[0003] In existing technologies, automatic transmission hydraulic control systems often use pilot solenoid valves and pressure regulating valve cores to control and regulate the oil pressure of hydraulic actuators such as clutches or brakes. Switching solenoid valves and switching valve cores are used to realize the failed gear when the transmission is not powered on, resulting in complex structure and high manufacturing cost.

[0004] This invention provides an automatic transmission hydraulic control system, specifically addressing how to prevent a driving state that does not match the target gear when a solenoid valve malfunctions, thereby ensuring driver safety. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides an automatic transmission hydraulic control system, the purpose of which is to avoid a driving state that does not match the target gear when the solenoid valve malfunctions, thereby ensuring driver safety.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an automatic transmission hydraulic control system, comprising: Mechanical oil pumps are used to supply pressurized oil. The main pressure regulating valve is located between the mechanical oil pump and the main oil circuit, and is used to regulate the oil pressure in the main oil circuit. A main pressure regulating solenoid valve, in conjunction with the main pressure regulating valve, is used to electrically regulate the oil pressure in the main oil circuit; A manual valve, located on the main oil line, has a forward gear position and a reverse gear position, and is used to selectively supply oil to the forward gear oil line or the reverse gear oil line according to the control of the shift actuator; A shuttle valve, which is connected to the forward oil passage and the reverse oil passage respectively, is used to supply oil to the target actuator and block the other oil passage when oil is supplied in either oil passage; Multiple clutch solenoid valves and brake solenoid valves are connected to the corresponding clutch or brake hydraulic actuators; and A first switching valve and a second switching valve, wherein the control end of the first switching valve is connected to the output oil circuit of at least two clutch solenoid valves, and the output end of the first switching valve is connected to the second switching valve; When the output oil pressure of any of the at least two clutch solenoid valves reaches the set condition, the first switching valve switches to the first position, so that the forward oil path acts on the second switching valve through the first switching valve. When the main pressure regulating solenoid valve is in a non-energized state, the second switching valve switches to a preset position under the action of the main oil circuit oil pressure, so that the forward gear oil circuit directly provides engagement oil pressure to the predetermined clutch hydraulic actuator to form a predetermined failure gear.

[0007] The manual valve has parking, reverse, neutral and forward positions. When in parking or neutral position, the main oil circuit is disconnected from the forward and reverse oil circuits.

[0008] When the manual valve is in the forward gear position, the main oil circuit supplies oil to the forward gear oil circuit to supply oil to at least part of the clutch solenoid valve, brake solenoid valve and shuttle valve.

[0009] When the manual valve is in a non-forward position, the forward gear oil circuit is connected to the return oil circuit through the manual valve, and a check valve is installed on the return oil circuit to prevent outside air from entering the hydraulic system.

[0010] Both the forward and reverse oil circuits are connected to the input end of the shuttle valve, and the output end of the shuttle valve is connected to at least one clutch solenoid valve to ensure that oil does not leak to the other oil circuit when oil is supplied to either oil circuit.

[0011] Both the clutch solenoid valve and the brake solenoid valve are normally closed direct-drive proportional solenoid valves, and their output oil circuits are directly connected to the corresponding hydraulic actuators.

[0012] The main pressure regulating solenoid valve is a normally open pilot-operated proportional solenoid valve, which outputs the maximum control oil pressure to the main pressure regulating valve when not energized.

[0013] The automatic transmission hydraulic control system also includes a pressure reducing valve, which is located on the main oil line to reduce the oil pressure in the main oil line to a predetermined range and to provide input oil pressure to the main pressure regulating solenoid valve.

[0014] The output oil circuit of the pressure reducing valve is connected to the control terminal of the second switching valve to apply hydraulic pressure in a predetermined direction to the valve core of the second switching valve.

[0015] When none of the clutch solenoid valves output oil pressure, the first switching valve is in its initial position under the action of the reset spring, thus disconnecting the forward oil blocking circuit from the second switching valve. When the second switching valve is in the preset position, the forward oil passage provides engagement oil pressure to at least two predetermined clutch hydraulic actuators via the second switching valve.

[0016] The automatic transmission hydraulic control system of the present invention fully utilizes the advantage of the simple structure of the direct-drive solenoid valve controlling the transmission clutch, and controls the opening and closing or switching of the input oil circuit of the direct-drive solenoid valve through a manual reversing valve and a shuttle valve, so as to avoid the driving state that does not match the target gear when the solenoid valve fails, thus ensuring the driving safety of the driver. At the same time, the application of the switching solenoid valve is eliminated, and the failure gear of the transmission is realized by using two switching valves, which greatly simplifies the structural design of the automatic transmission hydraulic control system and reduces the manufacturing cost. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the hydraulic control system for the automatic transmission of the present invention; The markings in the above diagrams are as follows: 1: Filter; 2: Mechanical oil pump; 3: Main pressure regulating valve; 31: Main pressure regulating valve core; 32: Main pressure regulating valve spring; 4: Shuttle valve; 41: Shuttle valve seat; 42: Steel ball; 43: Shuttle valve plug; 44: O-ring; 5: Manual valve; 51: Manual valve core; 6: First switching valve; 61: First switching valve core; 62: First switching spring; 7: Pressure reducing valve; 71: Pressure reducing valve core; 72: Pressure reducing valve spring; 8: Second switching valve; 81: Second switching valve core; 82: Second switching spring; 9: Check valve; 91: Check valve piston; 92: Check valve Spring; SPL: Main pressure regulating solenoid valve; SC1: First clutch solenoid valve; SC2: Second clutch solenoid valve; SC3: Third clutch solenoid valve; SC4: Fourth clutch solenoid valve; SB1: First brake solenoid valve; SB2: Second brake solenoid valve; PL: Main oil circuit; PD: Forward gear oil circuit; PR: Reverse gear oil circuit; RD: Pressure reducing oil circuit; RET: Return oil circuit; C1: First clutch; C2: Second clutch; C3: Third clutch; C4: Fourth clutch; B1: First brake; B2: Second brake. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0019] It should be noted that in the following embodiments, the terms "first", "second", "third" and "fourth" do not represent an absolute distinction in structure or function, nor do they represent the order of execution, but are merely for the convenience of description.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] like Figure 1 As shown, an embodiment of the present invention provides an automatic transmission hydraulic control system, comprising: Mechanical oil pump 2 is used to supply pressurized oil; The main pressure regulating valve 3 is located between the mechanical oil pump 2 and the main oil circuit PL, and is used to regulate the oil pressure of the main oil circuit PL. The main pressure regulating solenoid valve SPL, in conjunction with the main pressure regulating valve 3, is used to electrically regulate the oil pressure of the main oil circuit PL. Manual valve 5, located on the main oil circuit PL, has forward gear position and reverse gear position, and is used to selectively supply oil to the forward gear oil circuit PD or the reverse gear oil circuit PR according to the control of the shift actuator; Shuttle valve 4 is connected to the forward gear oil circuit PD and the reverse gear oil circuit PR respectively, and is used to supply oil to the target actuator when oil is supplied in either oil circuit and to block the other oil circuit; Multiple clutch solenoid valves and brake solenoid valves are connected to the corresponding clutch or brake hydraulic actuators; and First switching valve 6 and second switching valve 8, the control end of the first switching valve 6 is connected to the output oil circuit of at least two clutch solenoid valves, and the output end of the first switching valve 6 is connected to the second switching valve 8. When the output oil pressure of any of the at least two clutch solenoid valves reaches the set condition, the first switching valve 6 switches to the first position, so that the forward gear oil circuit PD acts on the second switching valve 8 through the first switching valve 6. When the main pressure regulating solenoid valve SPL is in a non-energized state, the second switching valve 8 is switched to a preset position under the action of the main oil circuit PL oil pressure, so that the forward gear oil circuit PD directly provides engagement oil pressure to the predetermined clutch hydraulic actuator to form the predetermined failure gear.

[0022] Specifically, in this embodiment of the invention, an automatic transmission hydraulic control system is provided, which uses a constant low direct drive solenoid valve to directly control the hydraulic actuators of the transmission, providing the transmission with eight forward gears and one reverse gear for gear control and switching; two switching valves are used to realize the failed gear when the transmission experiences a non-electrical fault, so as to achieve a compact structure and reduce costs.

[0023] In embodiments of the present invention, such as Figure 1As shown, the multiple clutch solenoid valves include a first clutch solenoid valve SC1, a second clutch solenoid valve SC2, a third clutch solenoid valve SC3, and a fourth clutch solenoid valve SC4, and the multiple brake solenoid valves include a first brake solenoid valve SB1 and a second brake solenoid valve SB2. The first clutch solenoid valve SC1 is connected to a first switching valve 6 and the first clutch C1 of the automatic transmission. The second switching valve 8 is connected to the second clutch C2 and the fourth clutch C4 of the automatic transmission. The third clutch solenoid valve SC3 is connected to the third clutch C3 of the automatic transmission. A shuttle valve 4 is connected to the third clutch solenoid valve SC3, and the third clutch solenoid valve SC3 is positioned between the shuttle valve 4 and the third clutch C3. The first brake solenoid valve SB1 is connected to the first brake of the automatic transmission, and the second brake solenoid valve SB2 is connected to the second brake of the automatic transmission.

[0024] In embodiments of the present invention, such as Figure 1 As shown, the mechanical oil pump 2 draws oil through the filter 1 and supplies oil to the entire hydraulic control system through the main pressure regulating valve 3. The main pressure regulating solenoid valve SPL regulates the oil pressure of the main oil circuit PL of the automatic transmission hydraulic control system. When the oil supply of the mechanical oil pump 2 is greater than the demand of the automatic transmission hydraulic control system, the excess oil returns to the oil suction port of the mechanical oil pump 2 through the return port of the main pressure regulating valve 3.

[0025] like Figure 1 As shown, the rotor of the mechanical oil pump 2 rotates to draw in oil, and filters impurities in the oil through the filter 1. The outlet of the mechanical oil pump 2 is connected to the oil inlet 3c of the main pressure regulating valve 3 to form the main oil circuit PL. The main pressure regulating valve 3 has a main oil pressure feedback port 3a on the far left, which is connected to the main oil circuit PL. The main pressure regulating valve 3 has a main pressure regulating spring 32 on the far right. The control port 3d of the main pressure regulating solenoid valve SPL is connected to the output oil pressure of the main pressure regulating solenoid valve SPL. The oil pressure of the main oil circuit PL is controlled and regulated by controlling the output oil pressure of the main pressure regulating solenoid valve SPL. When the output flow of the mechanical oil pump 2 is greater than the demand of the hydraulic control system, the valve core 31 of the main pressure regulating valve 3 moves to the right, discharging the excess oil through the return port 3b of the main oil pressure valve, and returning to the oil inlet of the mechanical oil pump 2 through the return oil circuit RET.

[0026] In this embodiment of the invention, the manual valve 5 is controlled by the automatic transmission shift actuator. The manual valve 5 has positions for parking (P), reverse (R), neutral (N), and drive (D). The transmission shift actuator fixes the valve core of the manual valve 5 in the corresponding "P", "R", "N", or "D" position according to the driver's shift command. When the manual valve 5 is in the parking or neutral position, the main oil circuit PL is disconnected from the drive oil circuit PD and the reverse oil circuit PR, and the oil in the main oil circuit PL cannot pass through the manual valve 5.

[0027] like Figure 1 As shown, when the manual valve 5 is in the forward gear position, the main oil circuit PL supplies oil to the forward gear oil circuit PD, which in turn supplies oil to at least some of the clutch solenoid valves, brake solenoid valves, and shuttle valve 4. Specifically, it supplies oil to the first clutch solenoid valve SC1, the second clutch solenoid valve SC2, the fourth clutch solenoid valve SC4, the first brake solenoid valve SB1, and shuttle valve 4. At this time, the oil in the main oil circuit PL enters the forward gear oil circuit PD through the forward gear oil port 5b of the manual valve 5, providing input oil pressure to the first clutch solenoid valve SC1, the second clutch solenoid valve SC2, the fourth clutch solenoid valve SC4, and the first brake solenoid valve SB1. All of the above clutch solenoid valves are direct-drive solenoid valves, directly controlling the corresponding clutch oil pressure. The first clutch C1, the second clutch C2, and the fourth clutch C4 are engaged, and the first brake applies the brakes.

[0028] In this embodiment of the invention, when the manual valve 5 is in a non-forward position, the forward gear oil circuit PD is connected to the return oil passage through the manual valve 5, and the oil in the forward gear oil circuit PD can be discharged outward through the manual valve 5. A check valve 9 is provided on the return oil passage to prevent outside air from entering the hydraulic system. Figure 1 As shown, when the manual valve core 51 is in the "non-D" position, the forward gear oil circuit PD can discharge oil through the forward gear drain port 5a of the manual valve 5. This structure is a safety redundancy function, designed to prevent the oil in the clutch piston from being discharged through the one-way valve 9 when the "non-forward gear" solenoid valve cannot discharge oil normally. When the oil pressure of the clutch piston discharge is less than the opening oil pressure of the one-way valve 9, the one-way valve 9 closes to prevent air from entering the forward gear oil circuit PD and causing unstable oil pressure.

[0029] In this embodiment of the invention, both the forward gear oil circuit PD and the reverse gear oil circuit PR are connected to the input end of the shuttle valve 4, and the output end of the shuttle valve 4 is connected to at least one clutch solenoid valve to ensure that oil does not leak into the other oil circuit when either oil circuit is supplied with oil. Specifically, both the forward gear oil circuit PD and the reverse gear oil circuit PR can supply oil to the third clutch solenoid valve SC3 through the shuttle valve 4, and oil will not leak into the other oil circuit when one oil circuit is supplied with oil. Figure 1 As shown, the forward gear oil circuit PD is connected to the forward gear oil port 4a of the shuttle valve 4. The steel ball 42 inside the shuttle valve 4 moves towards the plug 43 of the shuttle valve 4 (the plug 43 is located to the right of the steel ball 42 in the figure) under the action of the oil pressure of the forward gear oil circuit PD and forms a seal to prevent the oil in the forward gear oil circuit PD from leaking into the reverse gear oil circuit PR. The oil in the forward gear oil circuit PD provides input oil pressure to the third clutch solenoid valve SC3 through the output oil port 4b of the shuttle valve 4. The third clutch solenoid valve SC3 directly controls the oil pressure of the third clutch C3 and controls the third clutch C3 to engage.

[0030] In this embodiment of the invention, when the manual valve 5 is in reverse gear, the oil in the main oil circuit PL enters the reverse gear oil circuit PR to supply oil to the shuttle valve 4. Figure 1 As shown, when the manual valve core 51 is in the "R" position, the oil in the main oil circuit PL enters the reverse oil circuit PR through the reverse oil port 5d of the manual valve 5. The reverse oil circuit PR is connected to the reverse oil port 4c of the shuttle valve 4. Under the action of the oil pressure in the reverse oil circuit PR, the steel ball 42 of the shuttle valve 4 moves to the side of the valve seat 41 (the valve seat 41 is located to the left of the steel ball 42 in the figure) and forms a seal. The valve seat 41 is equipped with a sealing ring 44 to prevent the oil in the reverse oil circuit PR from leaking into the forward oil circuit PD. The oil entering the reverse oil circuit PR provides input oil pressure to the third clutch solenoid valve SC3 through the output oil port 4b of the shuttle valve 4 to control the working state of the third clutch C3.

[0031] like Figure 1 As shown, when the manual valve core 51 is in the "N" and "P" positions, the manual valve oil circuit inlet 5c is closed by the manual valve core 51, and the oil in the main oil circuit PL cannot pass through the manual valve; the input oil pressure of the second brake solenoid valve SB2 is provided by the main oil circuit PL, and the second brake can be controlled to engage or disengage regardless of the position of the manual valve core 51.

[0032] In this embodiment of the invention, the first clutch solenoid valve SC1, the second clutch solenoid valve SC2, the third clutch solenoid valve SC3, the fourth clutch solenoid valve SC4, the first brake solenoid valve SB1, and the second brake solenoid valve SB2 are all normally closed direct-drive proportional solenoid valves. The solenoid valves directly drive the hydraulic actuators without going through a mechanical valve core for pressure regulation, which simplifies the system structure while ensuring the control range and accuracy of the hydraulic control system. The main pressure regulating solenoid valve SPL is a normally open pilot-operated proportional solenoid valve that outputs maximum oil pressure when not energized.

[0033] In this embodiment of the invention, the main pressure regulating solenoid valve SPL is a normally open pilot proportional solenoid valve that outputs the maximum control oil pressure to the main pressure regulating valve 3 when not energized.

[0034] like Figure 1 As shown, the automatic transmission hydraulic control system of this embodiment of the invention also includes a pressure reducing valve 7. The pressure reducing valve 7 is disposed on the main oil circuit PL and is used to reduce the oil pressure of the main oil circuit PL to a predetermined range and to provide input oil pressure to the main pressure regulating solenoid valve SPL.

[0035] like Figure 1 As shown, the output oil circuit of the pressure reducing valve 7 is connected to the control terminal of the second switching valve 8 to apply hydraulic pressure in a predetermined direction (to the right in the figure) to the valve core of the second switching valve 8 in order to control the position of the valve core of the second switching valve 8.

[0036] like Figure 1As shown, the first switching valve 6 is connected to the output oil circuit of the first clutch solenoid valve SC1 and the second clutch solenoid valve SC2 respectively. When the force generated by the output oil pressure of the first clutch solenoid valve SC1 or the second clutch solenoid valve SC2 is greater than the spring force on the right side of the first switching valve 6, the valve core of the first switching valve 6 will be pushed to the right position. Thus, the oil in the forward gear oil circuit PD enters the second switching valve 8 through the first switching valve 6 and applies a force in a predetermined direction (to the right in the figure) to the valve core of the second switching valve 8. When the valve core of the second switching valve 8 is in the right position, the second clutch solenoid valve SC2 and the fourth clutch solenoid valve SC4 will provide control oil pressure to the second clutch C2 and the fourth clutch C4 respectively through the second switching valve 8.

[0037] When the transmission is in a non-energized state, the first clutch solenoid valve SC1 and the second clutch solenoid valve SC2 do not output oil pressure. The first switching valve 6 is in the left position under the action of the return spring force, and the oil in the forward gear oil circuit PD cannot enter the second switching valve 8 through the first switching valve 6. The main pressure regulating solenoid valve SPL outputs the maximum oil pressure in the non-energized state, applying a leftward force to the valve core of the second switching valve 8, so that the valve core of the second switching valve 8 is in the left position. The forward gear oil circuit PD provides engagement oil pressure to the second clutch C2 and the fourth clutch C4 through the second switching valve 8, so as to realize the failed gear in the non-energized state of the transmission and ensure the vehicle's limp function.

[0038] In this embodiment of the invention, when neither of the clutch solenoid valves outputs oil pressure, the first switching valve 6 is in its initial position under the action of the reset spring, causing the forward gear oil circuit PD to disconnect from the second switching valve 8; when the second switching valve 8 is in a preset position, the forward gear oil circuit PD provides engagement oil pressure to at least two predetermined clutch hydraulic actuators via the second switching valve 8.

[0039] like Figure 1 As shown, the main oil circuit PL oil enters the pressure reducing valve 7 from the first port 7b and exits from the second port 7c to form the pressure reducing oil circuit RD. The pressure reducing oil circuit RD is connected to the third port 7a of the pressure reducing valve 7 to generate feedback oil pressure. A pressure reducing valve spring 72 is installed on the far right of the pressure reducing valve 7. The magnitude of the spring force generated by the spring 72 determines the maximum oil pressure of the pressure reducing oil circuit RD. The pressure reducing oil circuit RD provides input oil pressure to the main pressure regulating solenoid valve SPL and is connected to the port 8b of the second switching valve 8 to apply a force to the valve core 81 of the second switching valve 8, causing it to move towards one end of the second switching valve 8 (the right end in the figure).

[0040] like Figure 1 As shown, the output oil pressure PC1 of the first clutch solenoid valve SC1 is connected to the second oil port 6b of the first switching valve 6, applying a force F in a predetermined direction (to the right in the figure) to the valve core 61 of the first switching valve 6. SC1The output oil pressure PC2 of the second clutch solenoid valve SC2 is connected to the first oil port 6a of the first switching valve 6, applying a force F in a predetermined direction (to the right as shown in the figure) to the valve core 61 of the first switching valve 6. SC2 A spring 62 is installed at one end of the first switching valve 6 (the rightmost end in the figure). The spring 62 applies a force F in a predetermined direction (to the left in the figure) to the valve core 61 of the first switching valve 6. sp1 When F SC1 Or F SC2 Or the combined force of the two is greater than the spring force F generated by the spring 62 of the first switching valve 6. sp1 When the valve core 61 of the first switching valve 6 is in the right position, the forward blocking oil circuit PD oil enters from the fourth port 6d of the first switching valve 6 and flows out from the third port 6c of the first switching valve 6. The fourth port 6d and the third port 6c are connected, and finally enter the second switching valve 8; conversely, when F SC1 Or F SC2 Or the combined force of the two is less than the spring force F generated by the spring 62 of the first switching valve 6. sp1 When the valve core 61 of the first switching valve 6 is in the left position, the oil port 6d of the first switching valve is closed by the valve core 61 of the first switching valve, and the oil in the forward blocking oil circuit PD cannot enter the second switching valve 8 through the first switching valve.

[0041] like Figure 1 As shown, the first port 8a of the second switching valve 8 is connected to the third port 6c of the first switching valve 6. When the valve core 61 of the first switching valve 6 is in the right position, the forward blocking oil pressure PD applies a force F in a predetermined direction (to the right as shown in the figure) to the valve core 81 of the second switching valve 8. PD The second port 8b of the second switching valve 8 is connected to the pressure reducing oil circuit RD. The oil pressure in the pressure reducing oil circuit RD applies a force F in a predetermined direction (to the right as shown in the figure) to the valve core 81 of the second switching valve 8. RD A spring 82 is provided on the left side of the valve core 81 of the second switching valve 8. The spring 82 applies a force F in a predetermined direction (to the right as shown in the figure) to the valve core 81. sp2 The third port 8k of the second switching valve 8 is connected to the output oil circuit of the main pressure regulating solenoid valve SPL. The output oil pressure of the main pressure regulating solenoid valve SPL applies a force F in a predetermined direction (to the left as shown in the figure) to the valve core 81 of the second switching valve 8. SPL When three rightward forces F are applied to the valve core 81 of the second switching valve 8... PD F RD and F sp2 The resultant force is greater than the force F acting to the left. SPLWhen the valve core 81 of the second switching valve 8 is in the right position, the output oil pressure PC2 of the second clutch solenoid valve SC2 enters through the fourth oil port 8e of the second switching valve 8 and flows out through the eighth oil port 8d of the second switching valve 8, ultimately providing control oil pressure for the second clutch C2; the output oil pressure PC4 of the fourth clutch solenoid valve SC4 enters through the fifth oil port 8h of the second switching valve 8 and flows out through the sixth oil port 8g of the second switching valve 8, ultimately providing control oil pressure for the fourth clutch C4.

[0042] like Figure 1 As shown, when the first clutch solenoid valve SC1 and the second clutch solenoid valve SC2 are not energized or the output oil pressure is low, the valve core 61 of the first switching valve 6 is in the left position. At this time, the forward gear oil pressure PD is cut off by the valve core 61 of the first switching valve 6, so no rightward force can be applied to the valve core 81 of the second switching valve 8. When the valve core 81 of the second switching valve 8 applies two rightward forces F... RD and F sp2 The resultant force is less than the force F acting to the left. SPL When the valve core 81 of the second switching valve 8 is in the left position, the forward gear oil (PD) enters through the seventh port 8c of the second switching valve 8 and flows out through the eighth port 8d, ultimately providing engagement pressure for the second clutch C2; the forward gear oil (PD) enters through the ninth port 8f of the second switching valve 8 and flows out through the sixth port 8g, ultimately providing engagement pressure for the fourth clutch C4. This achieves the failure gear in the non-power-on fault state of the transmission, ensuring that the vehicle can continue driving in the failure gear when a power failure occurs.

[0043] The automatic transmission hydraulic control system described above fully utilizes the advantage of the simple structure of the direct-drive solenoid valve controlling the transmission clutch. It controls the opening and closing or switching of the input oil circuit of the direct-drive solenoid valve through a manual directional valve and a shuttle valve, avoiding the occurrence of a driving state that does not match the target gear when the solenoid valve fails, thus ensuring the driver's driving safety. At the same time, it eliminates the application of the switching solenoid valve and uses two switching valve cores to realize the failed gear of the transmission, which greatly simplifies the structural design of the automatic transmission hydraulic control system and reduces manufacturing costs.

[0044] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. An automatic transmission hydraulic control system, characterized in that, include: Mechanical oil pumps are used to supply pressurized oil. The main pressure regulating valve is located between the mechanical oil pump and the main oil circuit, and is used to regulate the oil pressure in the main oil circuit. A main pressure regulating solenoid valve, in conjunction with the main pressure regulating valve, is used to electrically regulate the oil pressure in the main oil circuit; A manual valve, located on the main oil line, has a forward gear position and a reverse gear position, and is used to selectively supply oil to the forward gear oil line or the reverse gear oil line according to the control of the shift actuator; A shuttle valve, connected to both the forward and reverse oil circuits, is used to supply oil to the target actuator when oil is supplied through either circuit and to block the other circuit; and A first switching valve and a second switching valve, wherein the control end of the first switching valve is connected to the output oil circuit of at least two clutch solenoid valves, and the output end of the first switching valve is connected to the second switching valve; When the output oil pressure of any of the at least two clutch solenoid valves reaches the set condition, the first switching valve switches to the first position, so that the forward oil path acts on the second switching valve through the first switching valve. When the main pressure regulating solenoid valve is in a non-energized state, the second switching valve switches to a preset position under the action of the main oil circuit oil pressure, so that the forward gear oil circuit directly provides engagement oil pressure to the predetermined clutch hydraulic actuator to form a predetermined failure gear.

2. The automatic transmission hydraulic control system according to claim 1, characterized in that: The manual valve has parking, reverse, neutral and forward positions. When in parking or neutral position, the main oil circuit is disconnected from the forward and reverse oil circuits.

3. The automatic transmission hydraulic control system according to claim 2, characterized in that: When the manual valve is in the forward gear position, the main oil circuit supplies oil to the forward gear oil circuit to supply oil to at least part of the clutch solenoid valve, brake solenoid valve and shuttle valve.

4. The automatic transmission hydraulic control system according to any one of claims 1 to 3, characterized in that: When the manual valve is in a non-forward position, the forward gear oil circuit is connected to the return oil circuit through the manual valve, and a check valve is installed on the return oil circuit to prevent outside air from entering the hydraulic system.

5. The automatic transmission hydraulic control system according to any one of claims 1 to 3, characterized in that: Both the forward and reverse oil circuits are connected to the input end of the shuttle valve, and the output end of the shuttle valve is connected to at least one clutch solenoid valve to ensure that oil does not leak to the other oil circuit when oil is supplied to either oil circuit.

6. The automatic transmission hydraulic control system according to any one of claims 1 to 3, characterized in that: Both the clutch solenoid valve and the brake solenoid valve are normally closed direct-drive proportional solenoid valves, and their output oil circuits are directly connected to the corresponding hydraulic actuators.

7. The automatic transmission hydraulic control system according to any one of claims 1 to 3, characterized in that: The main pressure regulating solenoid valve is a normally open pilot-operated proportional solenoid valve, which outputs the maximum control oil pressure to the main pressure regulating valve when not energized.

8. The automatic transmission hydraulic control system according to any one of claims 1 to 3, characterized in that: It also includes a pressure reducing valve, which is installed on the main oil line to reduce the oil pressure in the main oil line to a predetermined range and to provide input oil pressure to the main pressure regulating solenoid valve.

9. The automatic transmission hydraulic control system according to claim 8, characterized in that: The output oil circuit of the pressure reducing valve is connected to the control terminal of the second switching valve to apply hydraulic pressure in a predetermined direction to the valve core of the second switching valve.

10. The automatic transmission hydraulic control system according to any one of claims 1 to 3, characterized in that: When none of the clutch solenoid valves output oil pressure, the first switching valve is in its initial position under the action of the reset spring, thus disconnecting the forward oil blocking circuit from the second switching valve. When the second switching valve is in the preset position, the forward oil passage provides engagement oil pressure to at least two predetermined clutch hydraulic actuators via the second switching valve.

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