Transmission hydraulic system pressure control device, method and vehicle

Abstract

This invention discloses a pressure control device, method, and vehicle for a transmission hydraulic system. The device includes: an electric pump and a mechanical pump connected in series between a hydraulic tank and the main hydraulic circuit; the outlet of the mechanical pump is connected to the main hydraulic circuit via a first hydraulic circuit; a pressure control module includes a pilot valve, a first mechanical spool valve, a second mechanical spool valve, and a control unit; the control unit controls the electric pump to start or stop operating according to the system's required pressure; the pilot valve controls the first and / or second mechanical spool valves to regulate the main hydraulic circuit pressure according to the system's required pressure. This transmission hydraulic system pressure control device, by setting up a series connection between the electric pump and the mechanical pump, and a mechanism combining a pilot valve with two mechanical spool valves, achieves pressure control of the hydraulic system under different operating conditions while reducing the power demand of the electric pump. It offers high pressure regulation accuracy, reduces the energy consumption of the hydraulic system, and improves system economy.

Description

Technical Field

[0001] This invention relates to the field of transmission hydraulic system design technology, and in particular to a transmission hydraulic system pressure control device, method, and vehicle. Background Technology

[0002] A transmission hydraulic system is a system that regulates the oil pressure generated by an oil pump to maintain a suitable main oil pressure level, and controls related oil circuits accordingly to achieve automatic transmission. The hydraulic control system includes a main oil supply circuit, a pressure control module, a clutch and shift control module, and a cooling and lubrication control module. These components work together to ensure the transmission operates efficiently and smoothly under various operating conditions.

[0003] In existing technologies, the pressure control module for the main oil circuit typically employs two control methods: 1) using a solenoid valve to control pressure, where the main oil circuit pressure is related to the solenoid valve's current; 2) using a combination of a solenoid valve and a mechanical valve, where the solenoid valve is designed as a pilot valve, and the pressure of the mechanical valve controls the main oil circuit pressure. Both methods have their advantages and disadvantages. The first method uses fewer valves and is less expensive, but requires higher precision from the solenoid valves. The second method uses more valves, but the pressure distributed across each valve is lower, and the precision requirement for the solenoid valves is not as high. Currently, a structure where one pilot valve controls one mechanical valve is commonly used for main oil circuit pressure control, resulting in poor oil pressure control performance.

[0004] Existing transmission hydraulic system designs encompass both the flow control requirements of clutches and shifting mechanisms, as well as the flow requirements for cooling and lubrication. Therefore, most existing transmission hydraulic control systems employ two oil pumps to meet the increasing cooling and lubrication flow demands at higher speeds. For the design of these oil pumps, especially in hybrid transmission hydraulic systems, a combination of a mechanical pump and an electric pump is typically used. When the engine is not running, the electric pump is used to meet the cooling and lubrication needs of various components, placing certain power requirements on the electric pump and increasing the overall power required by the hydraulic system, thus raising system energy consumption. Summary of the Invention

[0005] This invention provides a pressure control device, method, and vehicle for a transmission hydraulic system, to solve the problems of poor oil pressure control and high energy consumption of electric pumps in existing transmission hydraulic system designs, thereby reducing the energy consumption of the hydraulic system.

[0006] According to one aspect of the present invention, a pressure control device for a transmission hydraulic system is provided, comprising: an electric pump, a mechanical pump, a main oil circuit, a cooling and lubrication control module, and a pressure control module; the electric pump and the mechanical pump are connected in series between a hydraulic oil tank and the main oil circuit, the electric pump being used to amplify the oil pressure at the outlet of the mechanical pump; the outlet of the mechanical pump is connected to the main oil circuit via a first oil circuit, the first oil circuit being provided with a first check valve, the inlet of the first check valve being connected to the inlet of the electric pump, and the outlet of the first check valve being connected to the outlet of the electric pump and the main oil circuit respectively; the pressure control module includes a pilot valve, a first... The system comprises a mechanical slide valve, a second mechanical slide valve, and a control unit; the control unit is used to control the electric pump to start or stop operation according to the system demand pressure; the first mechanical slide valve is disposed between the oil outlet of the electric pump and the cooling and lubrication control module; the second mechanical slide valve is disposed between the oil outlet of the mechanical pump and the cooling and lubrication control module; the oil inlet of the pilot valve is connected to the main oil circuit, and the oil outlet of the pilot valve is connected via the pilot oil circuit to the spring-side control port of the first mechanical slide valve and the spring-side control port of the second mechanical slide valve, respectively; the pilot valve is used to control the first mechanical slide valve and / or the second mechanical slide valve to participate in regulating the main oil circuit pressure according to the system demand pressure.

[0007] Optionally, the first spring preload of the first mechanical slide valve is greater than the second spring preload of the second mechanical slide valve, and the lower limit of the opening pressure of the first mechanical slide valve is less than the upper limit of the regulating pressure of the second mechanical slide valve, and the upper limit of the regulating pressure is less than the first system demand pressure when the electric pump starts.

[0008] Optionally, the spring-opposite control port of the first mechanical slide valve is connected to the main oil circuit, and the spring-opposite control port of the second mechanical slide valve is also connected to the main oil circuit. When the pressure in the main oil circuit is less than the preload of the first spring, the first mechanical slide valve does not participate in regulating the pressure in the main oil circuit. When the system demand pressure is greater than the upper limit of the regulating pressure of the second mechanical slide valve, and the electric pump stops running, the pressure in the main oil circuit is maintained at the upper limit of the regulating pressure, and the first mechanical slide valve does not participate in regulating the pressure in the main oil circuit.

[0009] Optionally, the oil outlet of the electric pump is connected to the control port opposite the spring of the first mechanical slide valve; when the system demand pressure is greater than the upper limit of the regulating pressure of the second mechanical slide valve, and the electric pump is running, the first mechanical slide valve and the second mechanical slide valve simultaneously participate in regulating the main oil circuit pressure.

[0010] Optionally, the pressure control device of the transmission hydraulic system further includes a second oil circuit and a second check valve; the second check valve is located in the second oil circuit, the oil inlet of the second check valve is connected to the oil inlet of the mechanical pump via the second oil circuit, and the oil outlet of the second check valve is connected to the oil outlet of the mechanical pump and the oil inlet of the electric pump, respectively.

[0011] Optionally, the transmission hydraulic system pressure control device further includes: a vibration damping accumulator, which is connected in parallel in the pilot oil circuit, and is used to stabilize the pilot pressure output by the pilot valve.

[0012] Optionally, the pilot valve is a normally open electromagnetic proportional valve; the pilot pressure output by the pilot valve is negatively correlated with the control current of the pilot valve.

[0013] Optionally, the rotational speed of the mechanical pump is positively correlated with the engine speed.

[0014] According to another aspect of the present invention, a method for controlling the pressure of a transmission hydraulic system is provided, which is based on the above-mentioned transmission hydraulic system pressure control device. The transmission hydraulic system pressure control device includes an electric pump and a mechanical pump connected in series, and a first mechanical spool valve and a second mechanical spool valve controlled by the same pilot valve. The method includes: controlling the electric pump to start or stop operation according to the system demand pressure; and controlling the first mechanical spool valve and / or the second mechanical spool valve to participate in regulating the main oil circuit pressure according to the system demand pressure.

[0015] According to another aspect of the present invention, a vehicle is provided, comprising: a transmission, and a pressure control device for the transmission hydraulic system.

[0016] The technical solution of this invention involves setting up an electric pump and a mechanical pump connected in series. The electric pump is started or stopped according to the system pressure requirement. The electric pump amplifies the oil pressure at the outlet of the mechanical pump. Simultaneously, a pilot valve, a first mechanical spool valve, a second mechanical spool valve, and a control unit are included in the pressure control module. The pilot valve controls the first and / or second mechanical spool valves to participate in regulating the main oil circuit pressure according to the system pressure requirement. This solves the problems of poor oil pressure control and high energy consumption of electric pumps in existing transmission hydraulic system designs. It reduces the power requirement of the electric pump, thereby reducing the energy consumption of the hydraulic system and improving system economy. By using a control method with one pilot valve and two mechanical valves, the pressure regulation strategy can be adaptively adjusted under different operating conditions, improving pressure regulation accuracy.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the structure of a pressure control device for a transmission hydraulic system provided in an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of another pressure control device for a transmission hydraulic system provided in an embodiment of the present invention;

[0021] Figure 3 A flowchart of a pressure control method for a transmission hydraulic system provided in an embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] Figure 1 This is a schematic diagram of a pressure control device for a transmission hydraulic system provided in an embodiment of the present invention. This embodiment is applicable to application scenarios where two oil pumps are used for hydraulic system process control.

[0025] See Figure 1The transmission hydraulic system pressure control device of this application includes: an electric pump 1, a mechanical pump 2, a main oil circuit 101, a cooling and lubrication control module 102, and a pressure control module 3. The main oil circuit 101 is connected to the clutch and shift control module 103. The cooling and lubrication control module 102 outputs oil based on the cooling and lubrication requirements of the transmission or the entire vehicle. The clutch and shift control module 103 outputs oil based on the clutch and shift pressure requirements.

[0026] See Figure 1 In this application, the electric pump 1 and the mechanical pump 2 are connected in series between the hydraulic oil tank 4 and the main oil circuit 101. The oil outlet of the mechanical pump 2 is connected to the main oil circuit 101 via the first oil circuit 104. The first oil circuit 104 is provided with a first check valve 201. The oil inlet of the first check valve 201 is connected to the oil inlet of the electric pump 1, and the oil outlet of the first check valve 201 is connected to the oil outlet of the electric pump 1 and the main oil circuit 101, respectively. When neither mechanical pump 2 nor electric pump 1 is started, the oil flows from the hydraulic oil tank 4 through the inlet of mechanical pump 2, the outlet of mechanical pump 2, and the first oil passage 104, and into the main oil passage 101. When mechanical pump 2 is started and electric pump 1 is not started, the oil flows from the hydraulic oil tank 4 through the inlet of mechanical pump 2, the outlet of mechanical pump 2, and the first oil passage 104, and into the main oil passage 101. When both mechanical pump 2 and electric pump 1 are started, the oil flows from the hydraulic oil tank 4 through the inlet of mechanical pump 2, the outlet of mechanical pump 2, the inlet of electric pump 1, and the outlet of electric pump 1, and into the main oil passage 101. Electric pump 1 is used to amplify the oil pressure at the outlet of mechanical pump 2.

[0027] See Figure 1 The pressure control module 3 of this application includes a pilot valve 301, a first mechanical spool valve 302, a second mechanical spool valve 303, and a control unit 304. The pilot valve 301 can be understood as a control mechanism for controlling the first mechanical spool valve 302 and the second mechanical spool valve 303. The control unit can be understood as a transmission hydraulic system controller, used to control the start or stop of the electric pump 1 according to the system pressure demand. In this embodiment, the system pressure demand is the pressure demand of the main oil circuit 101. Optionally, the system pressure demand can be determined based on the pressure required by the clutch and shifting mechanism. Specifically, the electric pump 1 starts operating when the system pressure demand is high (e.g., higher than the pressure regulating capacity of the second mechanical spool valve 303). The system pressure demand can be determined by the engine speed; higher engine speed requires higher clutch pressure.

[0028] See Figure 1As shown, the first mechanical slide valve 302 is disposed between the oil outlet of the electric pump 1 and the cooling and lubrication control module 102; the second mechanical slide valve 303 is disposed between the oil outlet of the mechanical pump 2 and the cooling and lubrication control module 102; the oil inlet of the pilot valve 301 is connected to the main oil circuit 101, and the oil outlet of the pilot valve 301 is connected to the spring-side control port A1 of the first mechanical slide valve 302 and the spring-side control port B1 of the second mechanical slide valve 303 via the pilot oil circuit 106. The pilot valve 301 is used to control the first mechanical slide valve 302 and / or the second mechanical slide valve 303 to participate in regulating the pressure of the main oil circuit according to the system demand pressure. In this embodiment, the pilot pressure applied to the spring-side control port A1 of the first mechanical slide valve 302 and the spring-side control port B1 of the second mechanical slide valve 303 can be adjusted by controlling the opening degree of the pilot valve 301. The pilot pressure is in the same direction as the spring preload and is used to push the mechanical slide valve to the left.

[0029] In this embodiment, the second mechanical slide valve 303 is used to perform pressure regulation within a small pressure regulation range, and the first mechanical slide valve 302 is used to participate in pressure regulation when the pressure regulation capability of the second mechanical slide valve 303 is insufficient.

[0030] Specifically, during the operation of the transmission hydraulic system, the control unit identifies the system's required pressure based on engine speed. When the required system pressure is high (e.g., higher than the pressure regulating capacity of the second mechanical spool valve 303), it controls the electric pump 1 to start operating. The electric pump 1 amplifies the oil pressure at the outlet of the mechanical pump 2. Simultaneously, the pressure control module 3 includes a pilot valve 301, a first mechanical spool valve 302, and a second mechanical spool valve 303. When the required system pressure is low (e.g., lower than the pressure regulating capacity of the second mechanical spool valve 303), the pilot valve 301 controls the second mechanical spool valve 303 to participate in the pressure regulation. The main oil circuit pressure is adjusted. When the system requires a higher pressure (e.g., higher than the pressure regulating capacity of the second mechanical spool valve 303), the first mechanical spool valve 302 and the second mechanical spool valve 303 are controlled to jointly regulate the main oil circuit pressure. This solves the problems of poor oil pressure control and high energy consumption of electric pump 1 in the existing transmission hydraulic system design. The power requirement of electric pump 1 is reduced, which can reduce the energy consumption of the hydraulic system and improve the system economy. Through the control method of one pilot valve 301 and two mechanical valves, the pressure regulation strategy under different working conditions can be adaptively adjusted to improve the pressure regulation accuracy.

[0031] Optionally, the first spring preload of the first mechanical slide valve 302 is greater than the second spring preload of the second mechanical slide valve 303, and the lower limit of the opening pressure of the first mechanical slide valve 302 is less than the upper limit of the regulating pressure of the second mechanical slide valve 303, and the upper limit of the regulating pressure is less than the first system demand pressure when the electric pump 1 starts.

[0032] Specifically, the first spring preload can be understood as the maximum force applied by the spring to the first mechanical spool valve 302, and this force is in the same direction as the pilot pressure; the second spring preload can be understood as the maximum force applied by the spring to the second mechanical spool valve 303, and this force is in the same direction as the pilot pressure; the lower limit of the opening pressure of the first mechanical spool valve 302 can be understood as the minimum force required to move the first mechanical spool valve 302 to the conducting state, and this force is used to overcome the first spring preload and the pilot pressure; the upper limit of the regulating pressure of the second mechanical spool valve 303 can be understood as the maximum force of the second mechanical spool valve 303 in the maximum conducting state, and this force is used to overcome the second spring preload and the pilot pressure.

[0033] See Figure 1 As shown, the first mechanical spool valve 302 has a spring and a spring-side control port A1 on its right side, and a spring-opposite control port A2 on its left side; the second mechanical spool valve 303 has a spring and a spring-side control port B1 on its right side, and a spring-opposite control port B2 on its left side. The spring-opposite control port A2 of the first mechanical spool valve 302 is connected to the main oil circuit 101, and the spring-opposite control port B2 of the second mechanical spool valve 303 is also connected to the main oil circuit 101. When the first mechanical spool valve 302 participates in pressure regulation, the sum of the first spring preload and the pilot pressure applied to the spring-side control port A1 is balanced with the pressure applied to the spring-opposite control port A2 of the first mechanical spool valve 302 (i.e., the main oil circuit pressure). When the second mechanical slide valve 303 participates in pressure regulation, the sum of the second spring preload and the pilot pressure applied to the spring-side control port B1 is balanced with the pressure applied to the spring-side control port B2 of the second mechanical slide valve 303 (i.e., the main oil circuit pressure).

[0034] See Figure 1 As shown, when the main oil circuit pressure is less than the first spring preload, the first mechanical slide valve 302 does not participate in regulating the main oil circuit pressure; when the system demand pressure is greater than the upper limit of the regulating pressure of the second mechanical slide valve 303, and the electric pump 1 stops running, the main oil circuit pressure is maintained at the upper limit of the regulating pressure, and the first mechanical slide valve 302 does not participate in regulating the main oil circuit pressure.

[0035] Specifically, in the initial state, the main oil circuit 101 is empty, the main oil circuit pressure is zero, and all hydraulic components are in the positions shown in the diagram. When the mechanical pump 2 starts running and the electric pump 1 does not start, the oil in the hydraulic oil tank 4 first flows through the suction filter and is then delivered to the first oil circuit 104 by the mechanical pump 2. When the mechanical pump 2 just starts working, the second mechanical spool valve 303 is in the position shown in the diagram under the action of the right-side spring force. The initial oil pressure in the first oil circuit 104 is low. As the mechanical pump 2 operates, oil enters the main oil circuit 101. After the oil pressure increases and enters the main oil circuit 101, the main oil circuit pressure is still low and does not meet the system's required pressure. At this time, the main oil circuit pressure acts on the spring-opposite control port A2 of the first mechanical spool valve 302 and the spring-opposite control port B2 of the second mechanical spool valve 303 (e.g., ...). Figure 1 On the left side of the first mechanical spool valve 302 and the second mechanical spool valve 303 (the dotted lines), the spring force of the mechanical valve core (i.e., the first spring preload and the second spring preload) is overcome, thereby causing the valve core to move until it opens. At this time, by controlling the electromagnetic force of the pilot valve 301, the flow rate from the main oil circuit 101 to the pilot oil circuit 106 can be adjusted, thereby changing the pilot pressure (such as the spring-side control port A1 of the first mechanical spool valve 302 and the spring-side control port B1 of the second mechanical spool valve 303) acting on the pilot valve. Figure 1 The first mechanical spool valve 302 (shown as dashed lines to the right of the second mechanical spool valve 303) can further regulate the main oil circuit pressure. At this point, the main oil circuit pressure equals the sum of the pilot pressure output by the pilot valve 301 and the spring preload, thus achieving main oil circuit pressure control. When the main oil circuit pressure is low, the pressure on the left side of the first mechanical spool valve 302 is less than the spring force on the right side, and even less than the sum of the spring force and the hydraulic pressure controlled by the pilot valve 301. Therefore, the first mechanical spool valve 302 remains in the state shown in the diagram and cannot participate in the main oil circuit pressure regulation. Therefore, only the second mechanical spool valve 303 participates in the regulation during small-range pressure adjustments. When the system requires a high pressure, such as reaching the upper limit of the controllable pressure of the second mechanical spool valve 303, the pilot valve 301 can control the maximum pressure, and the hydraulic pressure acting on the first mechanical spool valve 302 is also the maximum. At this time, the main oil circuit pressure is still less than the sum of the first spring preload and the pilot pressure provided by the pilot valve 301. The first mechanical spool valve 302 remains closed, and the main oil circuit pressure can only be maintained at the upper limit of the controllable pressure of the second mechanical spool valve 303. The main oil circuit pressure cannot continue to increase. Therefore, a higher pressure can be achieved by controlling the electric pump to meet the needs of the hydraulic system.

[0036] See Figure 1 As shown, the oil outlet of the electric pump 1 is connected to the control port A2 on the opposite side of the spring of the first mechanical slide valve 302; when the system demand pressure is greater than the upper limit of the regulating pressure of the second mechanical slide valve 303, and the electric pump 1 is running, the first mechanical slide valve 302 and the second mechanical slide valve 303 simultaneously participate in regulating the main oil circuit pressure.

[0037] Specifically, if the system pressure requirement exceeds the upper limit of the adjustable pressure provided by the second mechanical slide valve 303, the control unit controls the electric pump 1 to start operating. At this time, the oil in the hydraulic oil tank 4 flows through the suction filter to the mechanical pump 2, then to the inlet of the electric pump 1, and finally enters the main oil circuit 101 from the outlet of the electric pump 1. When the mechanical pump 2 and the electric pump 1 start operating simultaneously, the pilot valve 301 first controls the second mechanical slide valve 303 to establish an initial pressure. This initial pressure is equal to the sum of the pilot pressure and the preload of the second spring. At this time, the inlet pressure of the electric pump 1 is equal to the initial pressure established by the second mechanical slide valve 303 and the pilot valve 301. After the oil enters the main oil circuit 101 via the electric pump 1, it passes through the damping orifice and acts on the spring-opposite control port A2 of the first mechanical spool valve 302. At this time, the pressure value of the spring-opposite control port A2 is the main oil circuit pressure, which is balanced with the pilot pressure provided by the pilot valve 301 and the preload force of the second spring. In the initial position, the first mechanical spool valve 302 is in the state shown in the figure, and the oil cannot flow into the third oil circuit 107. When the main oil circuit pressure reaches the system's required pressure, the first mechanical spool valve 302 is opened to ensure that the pressure does not continue to rise. Under the action of the second mechanical spool valve 303, the oil inlet of the electric pump 1 will generate oil with a certain pressure. When the oil enters the main oil circuit 101, the pressure is further regulated by the first mechanical spool valve 302. The pressure difference across the electric pump 1 is smaller than that of directly drawing oil from the oil tank and then regulating the main oil circuit pressure. The power requirement of the electric pump is reduced, thus reducing the overall energy consumption of the hydraulic system and improving economy.

[0038] See Figure 2 As shown, the pressure control device of the transmission hydraulic system of this application further includes a second oil circuit 105 and a second check valve 202; the second oil circuit 105 is arranged in parallel with the mechanical pump 2; the second check valve 202 is located in the second oil circuit 105, the oil inlet of the second check valve 202 is connected to the oil inlet of the mechanical pump 2 through the second oil circuit 105, and the oil outlet of the second check valve 202 is connected to the oil outlet of the mechanical pump 2 and the oil inlet of the electric pump 1, respectively.

[0039] Among them, the one-way valve is a valve body structure in which oil can only flow in from the inlet and flow out from the outlet. The first one-way valve 201 is connected to the electric pump 1 in parallel, and the second one-way valve 202 is connected to the mechanical pump 2 in parallel.

[0040] Specifically, when the outlet pressure of electric pump 1 is lower than the inlet pressure, the first check valve 201 is in the closed state, preventing oil from entering the main oil circuit 101. Therefore, electric pump 1 will not reverse, and oil will not flow out through electric pump 1, but will instead be delivered to the clutch and shift control module 103 via the main oil circuit 101. Due to the presence of the second check valve 202, oil will not flow back from the first oil circuit 104 to the second oil circuit 105. Thus, by designing the mechanical pump 2 and electric pump 1 with parallel check valves, the working spaces of mechanical pump 2 and electric pump 1 are separated, preventing interference or idling between mechanical pump 2 and electric pump 1, and avoiding self-priming by mechanical pump 2 or electric pump 1 from affecting the oil supply of the hydraulic system.

[0041] See Figure 2 As shown, the transmission hydraulic system pressure control device of this application further includes a vibration damping accumulator 5, which is connected in parallel in the pilot oil circuit 106. The vibration damping accumulator 5 is used to stabilize the pilot pressure output by the pilot valve 301. By connecting the vibration damping accumulator 5 in parallel in the pilot oil circuit, the pressure fluctuation is improved, and the pressure stability is enhanced.

[0042] Optionally, the pilot valve 301 is a normally open solenoid proportional valve; the pilot pressure output by the pilot valve 301 is negatively correlated with the control current of the pilot valve 301. Specifically, a normally open solenoid valve means that when the power supply current to the solenoid valve is zero, the inlet and outlet of the pilot valve 301 are connected, and the pilot pressure output by the pilot valve 301 is at its maximum. As the power supply current increases, the cross-sectional area of ​​the passage between the inlet and outlet of the pilot valve 301 decreases, and the pilot pressure output by the pilot valve 301 decreases accordingly. By adopting a normally open solenoid valve structure, it is ensured that even if the pilot valve 301 malfunctions and becomes uncontrollable, the main oil circuit pressure will not drop too low, and functions such as clutch and gear shift control can still be achieved, ensuring driving safety.

[0043] Optionally, the rotational speed of the mechanical pump 2 is positively correlated with the engine speed. Specifically, the power source for the mechanical pump 2 is the engine, and the rotational speed of the mechanical pump 2 is positively correlated with the engine speed; that is, the higher the engine speed, the higher the rotational speed of the mechanical pump 2. By setting a mechanical oil pump to regulate the oil circuit pressure, the cost of the hydraulic system can be reduced.

[0044] Based on the inventive concept of the above embodiments, the present invention provides a method for controlling the pressure of a transmission hydraulic system, which is implemented based on the above-mentioned transmission hydraulic system pressure control device. The transmission hydraulic system pressure control device includes an electric pump and a mechanical pump connected in series, and a first mechanical spool valve and a second mechanical spool valve controlled by the same pilot valve, and has the corresponding control logic and beneficial effects of the transmission hydraulic system pressure control device.

[0045] Figure 3A flowchart illustrating a pressure control method for a transmission hydraulic system provided in an embodiment of the present invention. See also... Figure 3 As shown, the transmission hydraulic system pressure control method of this application includes:

[0046] S1: Control the electric pump to start or stop operation according to the system's required pressure.

[0047] S2: Control the first mechanical slide valve and / or the second mechanical slide valve to participate in regulating the main oil circuit pressure according to the system demand pressure.

[0048] Optionally, the first spring preload of the first mechanical slide valve is greater than the second spring preload of the second mechanical slide valve, and the lower limit of the opening pressure of the first mechanical slide valve is less than the upper limit of the regulating pressure of the second mechanical slide valve, and the upper limit of the regulating pressure is less than the first system demand pressure when the electric pump starts.

[0049] Optionally, the first mechanical slide valve and / or the second mechanical slide valve are controlled to participate in regulating the main oil circuit pressure according to the system demand pressure, including: when the main oil circuit pressure is less than the first spring preload, the first mechanical slide valve does not participate in regulating the main oil circuit pressure; when the system demand pressure is greater than the upper limit of the regulating pressure of the second mechanical slide valve, and the electric pump stops running, the main oil circuit pressure is maintained at the upper limit of the regulating pressure, and the first mechanical slide valve does not participate in regulating the main oil circuit pressure.

[0050] Optionally, the first mechanical slide valve and / or the second mechanical slide valve are controlled to participate in regulating the main oil circuit pressure according to the system demand pressure, including: when the system demand pressure is greater than the upper limit of the regulating pressure of the second mechanical slide valve, and the electric pump is running, the first mechanical slide valve and the second mechanical slide valve participate in regulating the main oil circuit pressure simultaneously.

[0051] Based on the inventive concept of the above embodiments, the present invention also provides a vehicle, including: a transmission, and the above-mentioned transmission hydraulic system pressure control device, which has the corresponding functional modules and beneficial effects of the transmission hydraulic system pressure control device, and the same parts will not be described again.

[0052] In this embodiment, the vehicle is equipped with a transmission and a hydraulic system. The hydraulic system includes a main oil circuit connecting the clutch and shift control module, as well as a cooling and lubrication control module. This vehicle includes, but is not limited to, conventional energy vehicles or hybrid vehicles.

[0053] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0054] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A pressure control device for a transmission hydraulic system, characterized in that, include: Electric pump, mechanical pump, main oil circuit, cooling and lubrication control module, and pressure control module; The electric pump and the mechanical pump are connected in series between the hydraulic oil tank and the main oil circuit. The electric pump is used to amplify the oil pressure at the outlet of the mechanical pump. The outlet of the mechanical pump is connected to the main oil circuit via a first oil circuit. The first oil circuit is equipped with a first check valve. The inlet of the first check valve is connected to the inlet of the electric pump, and the outlet of the first check valve is connected to the outlet of the electric pump and the main oil circuit, respectively. The pressure control module includes a pilot valve, a first mechanical spool valve, a second mechanical spool valve, and a control unit; The control unit is used to control the electric pump to start or stop operating according to the system's required pressure. The first mechanical slide valve is located between the oil outlet of the electric pump and the cooling and lubrication control module; The second mechanical slide valve is located between the oil outlet of the mechanical pump and the cooling and lubrication control module; The inlet of the pilot valve is connected to the main oil circuit, and the outlet of the pilot valve is connected to the spring-side control port of the first mechanical slide valve and the spring-side control port of the second mechanical slide valve via the pilot oil circuit. The pilot valve is used to control the first mechanical slide valve and / or the second mechanical slide valve to participate in the adjustment of the main oil circuit pressure according to the system demand pressure.

2. The pressure control device for the transmission hydraulic system according to claim 1, characterized in that, The first spring preload of the first mechanical slide valve is greater than the second spring preload of the second mechanical slide valve, and the lower limit of the opening pressure of the first mechanical slide valve is less than the upper limit of the regulating pressure of the second mechanical slide valve, and the upper limit of the regulating pressure is less than the first system demand pressure when the electric pump starts.

3. The pressure control device for the transmission hydraulic system according to claim 2, characterized in that, The spring-opposite control port of the first mechanical slide valve is connected to the main oil circuit, and the spring-opposite control port of the second mechanical slide valve is connected to the main oil circuit. When the pressure in the main oil circuit is less than the preload of the first spring, the first mechanical slide valve does not participate in regulating the pressure in the main oil circuit. When the system demand pressure is greater than the upper limit of the regulating pressure of the second mechanical slide valve, and the electric pump stops running, the main oil circuit pressure is maintained at the upper limit of the regulating pressure, and the first mechanical slide valve does not participate in regulating the main oil circuit pressure.

4. The pressure control device for the transmission hydraulic system according to claim 2, characterized in that, The oil outlet of the electric pump is connected to the control port opposite the spring of the first mechanical slide valve; When the system demand pressure is greater than the upper limit of the regulating pressure of the second mechanical slide valve, and the electric pump is started, the first mechanical slide valve and the second mechanical slide valve simultaneously participate in regulating the main oil circuit pressure.

5. The pressure control device for the transmission hydraulic system according to claim 1, characterized in that, It also includes a second oil passage and a second check valve, wherein the second oil passage is connected in parallel with the mechanical pump; The second check valve is located in the second oil circuit. The oil inlet of the second check valve is connected to the oil inlet of the mechanical pump via the second oil circuit, and the oil outlet of the second check valve is connected to the oil outlet of the mechanical pump and the oil inlet of the electric pump, respectively.

6. The pressure control device for the transmission hydraulic system according to claim 1, characterized in that, Also includes: A vibration damping accumulator is provided in parallel in the pilot oil circuit. The vibration damping accumulator is used to stabilize the pilot pressure output by the pilot valve.

7. The pressure control device for the transmission hydraulic system according to any one of claims 1 to 6, characterized in that, The pilot valve is a normally open electromagnetic proportional valve. The pilot pressure output by the pilot valve is negatively correlated with the control current of the pilot valve.

8. The pressure control device for the transmission hydraulic system according to any one of claims 1 to 6, characterized in that, The rotational speed of the mechanical pump is positively correlated with the engine speed.

9. A pressure control method for a transmission hydraulic system, characterized in that, The method is implemented based on the transmission hydraulic system pressure control device according to any one of claims 1 to 8, wherein the transmission hydraulic system pressure control device includes an electric pump and a mechanical pump connected in series, and a first mechanical spool valve and a second mechanical spool valve controlled by the same pilot valve, and the method includes: The electric pump is started or stopped according to the system's required pressure control. According to the system's required pressure, the first mechanical slide valve and / or the second mechanical slide valve are controlled to participate in regulating the main oil circuit pressure.

10. A vehicle, characterized in that, include: A transmission, and a pressure control device for the transmission hydraulic system according to any one of claims 1 to 8.

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