Hydraulic system, automatic transmission and automobile having the same

Abstract

The present invention provides a hydraulic system, comprising: a high-pressure circuit and a high-pressure hydraulic pump for supplying pressurized fluid to the high-pressure circuit; a low-pressure circuit and a low-pressure hydraulic pump for supplying pressurized fluid to the low-pressure circuit; and a valve, the valve being arranged between the outlet side of the high-pressure hydraulic pump and the outlet side of the low-pressure hydraulic pump, and the valve having a first switch position and a second switch position, when the valve is in the first switch position, the outlet side of the high-pressure hydraulic pump is disconnected from the outlet side of the low-pressure hydraulic pump, and the low-pressure circuit supplies pressurized fluid through the low-pressure hydraulic pump, when the valve is in the second switch position, the outlet side of the high-pressure hydraulic pump is connected to the outlet side of the low-pressure hydraulic pump, and the low-pressure circuit supplies pressurized fluid through the high-pressure hydraulic pump and the low-pressure hydraulic pump. The hydraulic system can supply redundant pressurized fluid output by the high-pressure hydraulic pump to the low-pressure circuit, avoiding energy waste, and has a simple structure. The present invention also provides an automatic transmission and a car including the above-mentioned hydraulic system.

Description

Technical Field

[0001] The present invention relates to the technical field of automobiles, and in particular to a hydraulic system and an automatic transmission and an automobile having the hydraulic system. Background Art

[0002] The hydraulic system for the automatic transmission in a car is usually equipped with a high-pressure hydraulic pump and a low-pressure hydraulic pump. The high-pressure hydraulic pump is used to generate high hydraulic pressure and supply pressurized oil to the high-pressure circuit to actuate the automatic transmission's shifting, parking and other actuators, and the low-pressure hydraulic pump is used to generate low hydraulic pressure and supply pressurized oil to the low-pressure circuit to cool / lubricate multiple components of the automatic transmission.

[0003] In existing automatic transmissions, the high-pressure hydraulic pump and the low-pressure hydraulic pump in the hydraulic system often independently supply pressurized fluid to the corresponding high-pressure circuit and low-pressure circuit respectively. When the actuator is not working, on the one hand, the redundant pressurized fluid output by the high-pressure hydraulic pump is usually directly unloaded and therefore not fully utilized. On the other hand, an additional clutch is required between the high-pressure hydraulic pump and its drive unit to control the shutdown of the high-pressure hydraulic pump, which results in a relatively complex overall structure, which is not conducive to the miniaturization, lightweight and low-cost development of the hydraulic system. Summary of the invention

[0004] The object of the present invention is to provide a hydraulic system with a simple structure and conducive to reducing energy consumption. The hydraulic system is particularly suitable for application in automatic transmissions, especially dual-clutch automatic transmissions.

[0005] The technical solution adopted by the hydraulic system of the present invention is:

[0006] A hydraulic system comprising:

[0007] a high pressure circuit and a high pressure hydraulic pump for supplying pressurized fluid to the high pressure circuit;

[0008] a low-pressure circuit and a low-pressure hydraulic pump for supplying pressurized fluid to the low-pressure circuit;

[0009] and a valve, wherein the valve is arranged between the outlet side of the high-pressure hydraulic pump and the outlet side of the low-pressure hydraulic pump, and the valve has a first switch position and a second switch position. When the valve is in the first switch position, the outlet side of the high-pressure hydraulic pump is disconnected from the outlet side of the low-pressure hydraulic pump, and the low-pressure circuit is supplied with pressurized fluid by the low-pressure hydraulic pump. When the valve is in the second switch position, the outlet side of the high-pressure hydraulic pump is connected to the outlet side of the low-pressure hydraulic pump, and the low-pressure circuit is supplied with pressurized fluid through the high-pressure hydraulic pump and the low-pressure hydraulic pump.

[0010] Further, the high-pressure hydraulic pump and the low-pressure hydraulic pump are driven by a common drive unit.

[0011] Furthermore, the driving unit is a motor controlled by a TCU.

[0012] Further, the outlet side of the high-pressure hydraulic pump is connected to the first connector of the valve through a first pressure pipeline and connected to the high-pressure circuit through a second pressure pipeline connected to the first pressure pipeline, and a one-way valve is provided in the second pressure pipeline;

[0013] The outlet side of the low-pressure hydraulic pump is connected to the second connector of the valve via a third pressure line and is connected to the low-pressure circuit via a fourth pressure line connected to the third pressure line;

[0014] When the valve is in the first switch position, the first connector and the second connector are closed, and the first pressure line and the third pressure line are disconnected; when the valve is in the second switch position, the first connector and the second connector are connected, and the first pressure line and the third pressure line are connected.

[0015] Furthermore, at least one of the inlet side of the high-pressure hydraulic pump, the inlet side of the low-pressure hydraulic pump, and the inlet side of the one-way valve is provided with a filter element.

[0016] Furthermore, the valve also has a control end, and the control end is provided with a control element for controlling the valve to switch between the first switch position and the second switch position, and the control element is an electromagnet or a hydraulic valve.

[0017] Furthermore, the hydraulic valve is arranged between the valve and the outlet side of the high-pressure hydraulic pump, and the hydraulic valve has a third switching position and a fourth switching position. When the hydraulic valve is in the third switching position, the hydraulic valve is in a disconnected state, and the valve is in the first switching position. When the hydraulic valve is in the fourth switching position, the hydraulic valve is in a conducting state, and the valve can be switched from the first switching position to the second switching position when the hydraulic valve is in the conducting state.

[0018] Furthermore, an accumulator is connected in parallel to the second pressure pipeline.

[0019] The present invention also provides an automatic transmission comprising the hydraulic system.

[0020] In addition, the present invention also provides a car comprising the automatic transmission.

[0021] Based on the above technical solution, the hydraulic system of the present invention and the automatic transmission and automobile having the hydraulic system have at least the following beneficial effects compared with the prior art:

[0022] The hydraulic system of the present invention arranges the above-mentioned valve between the outlet side of the high-pressure hydraulic pump and the outlet side of the low-pressure hydraulic pump. When the high-pressure circuit meets the demand, the valve can be switched to the second switch position to connect the outlet side of the high-pressure hydraulic pump and the outlet side of the low-pressure hydraulic pump, so that the redundant pressurized fluid output by the high-pressure hydraulic pump can be supplied to the low-pressure circuit, thereby achieving full utilization of the pressurized fluid output by the high-pressure hydraulic pump. The hydraulic system not only avoids energy waste, but also helps to improve the working efficiency of the low-pressure circuit. It has a simple structure and is suitable for promotion and application in automatic transmissions of automobiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A structural schematic diagram of a hydraulic system provided by an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of the structure of another hydraulic system provided by an embodiment of the present invention;

[0025] Description of reference numerals:

[0026] 1- low-pressure hydraulic pump; 2- high-pressure hydraulic pump; 3- low-pressure circuit; 4- high-pressure circuit; 5- drive unit; 6- valve; 7- accumulator; 8- one-way valve; 9- first filter element; 10- second filter element; 11- first pressure line; 12- first connector; 13- second connector; 14- third pressure line; 15- second pressure line; 16- third filter element; 17- first oil tank; 18- second oil tank; 19- electromagnet; 20- hydraulic valve; 21- third connector; 22- fourth connector; 23- fourth pressure line. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] It should be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0029] In the description of the present invention, it is to be understood that the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the feature. In the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0030] It should also be noted that the directional terms such as up, down, top, bottom, side, left, and right in the following embodiments are merely relative concepts or are based on the normal use status of the product and should not be considered as restrictive.

[0031] Please refer to Figure 1 and Figure 2 , an embodiment of the present invention provides a hydraulic system, comprising:

[0032] a high-pressure circuit 4 and a high-pressure hydraulic pump 2 for supplying pressurized fluid to the high-pressure circuit 4;

[0033] a low-pressure circuit 3 and a low-pressure hydraulic pump 1 for supplying pressurized fluid to the low-pressure circuit 3;

[0034] And valve 6, valve 6 is arranged between the outlet side of the high-pressure hydraulic pump 2 and the outlet side of the low-pressure hydraulic pump 1, and valve 6 has a first switch position and a second switch position. When valve 6 is in the first switch position, the outlet side of the high-pressure hydraulic pump 2 is disconnected from the outlet side of the low-pressure hydraulic pump 1, and the low-pressure circuit 3 supplies pressurized fluid through the low-pressure hydraulic pump 1. When valve 6 is in the second switch position, the outlet side of the high-pressure hydraulic pump 2 is connected to the outlet side of the low-pressure hydraulic pump 1, and the low-pressure circuit 3 supplies pressurized fluid through both the high-pressure hydraulic pump 2 and the low-pressure hydraulic pump 1.

[0035] The hydraulic system sets a valve 6 between the outlet side of the high-pressure hydraulic pump 2 and the outlet side of the low-pressure hydraulic pump 1. When the high-pressure circuit 4 meets the demand, the valve 6 can be switched to the second switch position to make the outlet side of the high-pressure hydraulic pump 2 and the outlet side of the low-pressure hydraulic pump 1 conductive, so as to supply the redundant pressurized fluid output by the high-pressure hydraulic pump 2 to the low-pressure circuit 3. In this way, on the one hand, the pressurized fluid output by the high-pressure hydraulic pump 2 is fully utilized to improve the utilization efficiency of the hydraulic system. On the other hand, the common supply of the high-pressure hydraulic pump 2 and the low-pressure hydraulic pump 1 to the low-pressure circuit 3 is also conducive to improving the working efficiency of the low-pressure circuit 3. The overall structure of the hydraulic system is simple, and the layout and control are relatively convenient. It is particularly suitable for promotion and application in the automatic transmission of automobiles.

[0036] When the above-mentioned hydraulic system is used in an automatic transmission (not shown) of an automobile, the high-pressure circuit 4 of the hydraulic system specifically utilizes the pressurized fluid supplied by the high-pressure hydraulic pump 2 to hydraulically operate the shifting, parking, clutching and other actuators (not shown) in the automatic transmission, and the low-pressure circuit 3 specifically utilizes the pressurized fluid supplied by the low-pressure hydraulic pump 1 (and the high-pressure hydraulic pump 2) to cool and / or lubricate multiple components of the automatic transmission (not shown).

[0037] It should be noted that, for the hydraulic system used in the automatic transmission, the pressurized fluid is oil, and the same applies to the following text, so it will not be repeated here.

[0038] In some embodiments, please refer to Figure 1 and Figure 2 The inlet side of the low-pressure hydraulic pump 1 can be connected to the first oil tank 17 , and the inlet side of the high-pressure hydraulic pump 2 can be connected to the second oil tank 18 .

[0039] In some embodiments, the inlet sides of the high-pressure hydraulic pump 2 and the low-pressure hydraulic pump 1 may also be connected to the same oil tank, which is not limited here.

[0040] As a preferred embodiment of the present invention, please refer to Figure 1 and Figure 2 The high-pressure hydraulic pump 2 and the low-pressure hydraulic pump 1 are driven by a common drive unit 5. Using the same drive unit 5 to drive the high-pressure hydraulic pump 2 and the low-pressure hydraulic pump 1 can greatly simplify the structure, thereby facilitating the lightweight, miniaturization and low-cost development of the hydraulic system. The drive unit 5 is preferably a motor.

[0041] It is further preferred that the drive unit 5 is a motor controlled by a TCU (Transmission Control Unit, i.e., an automatic transmission control unit, not shown). By using a motor as the drive unit 5, the operation of the high-pressure hydraulic pump 2 and the low-pressure hydraulic pump 1 can be accurately controlled by utilizing the different rotation speeds of the motor. By controlling the motor by the TCU, on the one hand, the operation of the motor can be automatically controlled according to the working state requirements of the automatic transmission, thereby better adjusting the flow of the pressurized fluid output by the low-pressure hydraulic pump 1 and the high-pressure hydraulic pump 2, which is more conducive to achieving a low level of energy consumption. On the other hand, there is no need to set a clutch between the high-pressure hydraulic pump 2 and the motor to control the start / shutdown of the high-pressure hydraulic pump 2, thereby further simplifying the structure of the hydraulic system, reducing the layout space, and avoiding the hidden dangers of failure caused by the use of the clutch.

[0042] Specifically in this embodiment, please refer to Figure 1 and Figure 2The outlet side of the high-pressure hydraulic pump 2 is connected to the first connector 12 of the valve 6 through the first pressure line 11, and the outlet side of the high-pressure hydraulic pump 2 is also connected to the high-pressure circuit 4 through the second pressure line 15 connected to the first pressure line 11. A one-way valve 8 is provided in the second pressure line 15. The one-way valve 8 allows the pressurized fluid to flow from the first pressure line 11 to the second pressure line 15, but not from the second pressure line 15 to the first pressure line 11, thereby facilitating the stability of the operation of the high-pressure circuit 4. The outlet side of the low-pressure hydraulic pump 1 is connected to the second connector 13 of the valve 6 through the third pressure line 14, and the outlet side of the low-pressure hydraulic pump 1 is also connected to the low-pressure circuit 3 through the fourth pressure line 23 connected to the third pressure line 14.

[0043] When the valve 6 is in the first switch position, its first connector 12 and the second connector 13 are closed, the first pressure line 11 and the third pressure line 14 are disconnected, and accordingly, the high-pressure circuit 4 supplies pressurized fluid through the high-pressure hydraulic pump 2, and the low-pressure circuit 3 supplies pressurized fluid through the low-pressure hydraulic pump 1. When the valve 6 is in the second switch position, its first connector 12 and the second connector 13 are connected, the first pressure line 11 and the third pressure line 14 are connected, and accordingly, the low-pressure circuit 3 can supply pressurized fluid through the low-pressure hydraulic pump 1 and the high-pressure hydraulic pump 2. That is, in this embodiment, the valve 6 can be a common two-position two-way valve 6, which has a simple structure and low cost.

[0044] Specifically in the present embodiment, the valve 6 can be pre-tightened in the first switch position by an elastic element (such as a common spring) in the initial state so that the first connector 12 and the second connector 13 remain disconnected initially, and the pressurized fluid output from the outlet side of the high-pressure hydraulic pump 2 is supplied to the high-pressure circuit 4 through the first pressure line 11, the second pressure line 15 and the check valve 6 in sequence, and the pressurized fluid output from the outlet side of the low-pressure hydraulic pump 1 is supplied to the low-pressure circuit 3 through the third pressure line 14 and the fourth pressure line 23 in sequence.

[0045] When the pressure of the pressurized fluid in the high-pressure circuit 4 is sufficient, if the low-pressure circuit 3 in the hydraulic system needs to cool / lubricate the components of the automatic transmission (or the low-pressure hydraulic pump 1 is in a working state of supplying pressurized fluid to the low-pressure circuit 33), then at this time, the valve 6 can be switched from the initial first switch position to the second switch position, so that the first connector 12 and the second connector 13 are connected, and accordingly, the first pressure line 11 and the third pressure line 14 are connected. In this way, the high-pressure hydraulic pump 2 and the low-pressure hydraulic pump 1 together form almost no large pressure, and the redundant pressurized fluid output from the outlet side of the high-pressure hydraulic pump 2 can be supplied to the low-pressure circuit 3 together with the pressurized fluid output by the low-pressure hydraulic pump 1 for cooling / lubrication, so that the energy is fully utilized.

[0046] As a preferred embodiment of the present invention, please refer to Figure 1 and Figure 2 The inlet side of the low-pressure hydraulic pump 1 is provided with a first filter element 9, and the inlet side of the high-pressure hydraulic pump 2 is provided with a second filter element 10. The second filter element 10 and the first filter element 9 can filter the oil in the oil tank to ensure that the oil entering the high-pressure hydraulic pump 2 and the low-pressure hydraulic pump 1 has a good cleanliness level. In practical applications, in order to obtain a cleaner fluid and simplify the structure at the same time, the inlet side of the high-pressure hydraulic pump 2 and the inlet side of the low-pressure hydraulic pump 1 can be connected, so that only one filter element needs to be arranged to purify the fluid in the oil tank. In addition, in some embodiments, the inlet side of the low-pressure hydraulic pump 1 and the inlet side of the high-pressure hydraulic pump 2 can also be connected to a common oil tank with a spacer filter.

[0047] As a preferred embodiment of the present invention, please refer to Figure 1 and Figure 2 The inlet side of the one-way valve 8 may also be provided with a third filter element 16 to further ensure the cleanliness of the oil supplied to the high-pressure circuit 4, thereby improving the working performance of the automatic transmission. Specifically in this embodiment, the filter element 16 is provided on the second pressure line 15, and a certain pressure difference resistance can be formed in the second pressure line 15. When the valve 6 is in the second switch position, it is more conducive to the pressurized fluid output by the high-pressure hydraulic pump 2 to flow to the low-pressure circuit 3 through the first pressure line 11.

[0048] The filter element 16 can be a filter or other existing filter devices.

[0049] Specifically in this embodiment, the valve 6 further has a control end, and the control end is provided with a control element for controlling the valve 6 to switch between the first switch position and the second switch position.

[0050] A preferred structure is, please refer to Figure 1 , the control element is an electromagnet 19. In this way, the electromagnet 19 can be used for direct control, which has a simple structure and convenient control, and is conducive to reducing weight, reducing system space, and reducing costs.

[0051] In practical application, the electromagnet 19 can specifically control the valve 6 in an existing switch control mode or a proportional control mode.

[0052] Another preferred structure is, please refer to Figure 2 The control element is a hydraulic valve 20. The hydraulic control is performed using the hydraulic valve 20. The switch position of the valve 6 can be controlled according to the fluid pressure at the outlet side of the high-pressure hydraulic pump 2, which is also convenient and accurate.

[0053] As a preferred embodiment of the present invention, please refer to Figure 2 The hydraulic valve 20 is arranged between the valve 6 and the outlet side of the high-pressure hydraulic pump 2. The hydraulic valve 20 has a third switch position and a fourth switch position. When the hydraulic valve 20 is in the third switch position, the hydraulic valve 20 is in a disconnected state and the valve 6 is in the first switch position. When the hydraulic valve 20 is in the fourth switch position, the hydraulic valve 20 is in a conducting state. The valve 6 can be switched from the first switch position to the second switch position when the hydraulic valve 20 is in the conducting state.

[0054] Specifically, the hydraulic valve 20 may be provided with a third connector 21 and a fourth connector 22 . The hydraulic valve 20 is connected to the high-pressure circuit 4 via the third connector 21 , and is connected to the control end of the valve 6 via the fourth connector 22 .

[0055] When the automatic transmission actuator corresponding to the above-mentioned high-pressure circuit 4 is in a working state or the low-pressure circuit 3 does not need to cool / lubricate the automatic transmission (or the low-pressure hydraulic pump 1 is in a non-working state), the third connector 21 and the fourth connector 22 of the hydraulic valve 20 are disconnected, the hydraulic valve 20 is in the third switching position, and the valve 6 is pre-tightened by a spring in the initial first switching position, thereby realizing the disconnection of the control end of the valve 6 from the high-pressure circuit 4.

[0056] When the pressure of the high-pressure circuit 4 meets the requirement and the low-pressure circuit 3 needs to cool / lubricate the automatic transmission (or the low-pressure hydraulic pump 1 is in working state), the third connector 21 and the fourth connector 22 of the hydraulic valve 20 are connected, the hydraulic valve 20 is in the fourth switch position, the high-pressure circuit 4 is connected to the control end of the valve 6, and the valve 6 overcomes the preload force of the spring under the action of the hydraulic pressure output by the hydraulic valve 20 and switches from the first switch position to the second switch position, so that the first connector 12 is connected to the second connector 13, and the first pressure line 11 on the outlet side of the high-pressure hydraulic pump 2 is connected to the third pressure line 14 on the outlet side of the low-pressure hydraulic pump 1 and the low-pressure circuit 3. In this way, the high-pressure hydraulic pump 2 and the low-pressure hydraulic pump 1 together form almost no large pressure, and the redundant pressurized fluid output from the outlet side of the high-pressure hydraulic pump 2 can be supplied to the low-pressure circuit 3 together with the pressurized fluid output by the low-pressure hydraulic pump 1 for cooling / lubricating the automatic transmission.

[0057] Specifically in this embodiment, please refer to Figure 2 The control end of the hydraulic valve 20 may also be provided with an electromagnet 19, and the electromagnet 19 is used to control the switching between the third switch position and the fourth switch position.

[0058] As a preferred embodiment of the present invention, please refer to Figure 1 and Figure 2The second pressure line 15 is also connected in parallel with an accumulator 7. The accumulator 7 can convert the energy of the high-pressure circuit 4 into compressed energy storage at an appropriate time (for example, when the hydraulic pressure output by the high-pressure hydraulic pump 2 is large), and convert the compressed energy into hydraulic energy for release when the high-pressure circuit 4 needs it, thereby resupplying the high-pressure circuit 4 to improve energy utilization and reduce energy consumption. In addition, when the instantaneous pressure on the outlet side of the high-pressure hydraulic pump 2 increases, this part of the energy can also be absorbed to ensure the normal and stable operation of the entire system pressure.

[0059] Specifically in this embodiment, please refer to Figure 1 and Figure 2 The accumulator 7 is arranged on the outlet side of the one-way valve 8.

[0060] As a preferred embodiment of the present invention, please refer to Figure 2 , the hydraulic valve 20 can be arranged at the control end of the valve 6 and the outlet side of the one-way valve 8. In this way, the redundant oil at the outlet side of the high-pressure hydraulic pump 2 can be further fully utilized (supplied to the third pressure pipeline 14 through the hydraulic valve 20 and the first pressure pipeline 11 respectively), and the one-way valve 8 can be used to improve the stability and reliability of the operation of the hydraulic system. In addition, the accumulator 7 can be used to supply the low-pressure circuit 3 as needed, which is more flexible to use.

[0061] Specifically in this embodiment, the hydraulic valve 20 may be an existing pilot pressure valve.

[0062] It should be understood that, in actual application, the one-way valve 8 may also be provided in the fourth pressure line 23 to prevent the oil from flowing back from the fourth pressure line 23 to the third pressure line 14 .

[0063] In practical applications, a filter element may be further provided in the fourth pressure pipeline 23 to improve the cleanliness level of the oil.

[0064] It should also be noted that the above-mentioned first pressure line 11, second pressure line 15, third pressure line 14, and fourth pressure line 23 should not be narrowly understood as necessarily being closed pipes or channels. Those skilled in the art can understand that in some extreme cases, some pressure lines can be implemented only by a valve body connector.

[0065] An embodiment of the present invention further provides an automatic transmission including the above hydraulic system.

[0066] The above automatic transmission is based on the same concept as the above hydraulic system embodiment, and the technical effect it brings is the same as the above hydraulic system embodiment of the present invention. For details, please refer to the description of the above hydraulic system embodiment of the present invention, and no further description will be given here.

[0067] In addition, an embodiment of the present invention also provides a car including the automatic transmission.

[0068] The above-mentioned automobile is based on the same concept as the above-mentioned hydraulic system embodiment, and the technical effect it brings is the same as the above-mentioned hydraulic system embodiment of the present invention. The specific contents can be found in the description of the above-mentioned hydraulic system embodiment of the present invention, which will not be repeated here.

[0069] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A hydraulic system, characterized in that: include: a high pressure circuit and a high pressure hydraulic pump for supplying pressurized fluid to the high pressure circuit; a low-pressure circuit and a low-pressure hydraulic pump for supplying pressurized fluid to the low-pressure circuit; and a valve, the valve being provided between the outlet side of the high-pressure hydraulic pump and the outlet side of the low-pressure hydraulic pump, and the valve having a first switch position and a second switch position, when the valve is in the first switch position, the outlet side of the high-pressure hydraulic pump is disconnected from the outlet side of the low-pressure hydraulic pump, and the low-pressure circuit supplies pressurized fluid through the low-pressure hydraulic pump, and when the valve is in the second switch position, the outlet side of the high-pressure hydraulic pump is connected to the outlet side of the low-pressure hydraulic pump, and the low-pressure circuit supplies pressurized fluid through both the high-pressure hydraulic pump and the low-pressure hydraulic pump; The valve further has a control end, the control end is provided with a control element for controlling the valve to switch between the first switch position and the second switch position, and the control element is a hydraulic valve; The hydraulic valve is arranged between the valve and the outlet side of the high-pressure hydraulic pump, and the hydraulic valve has a third switch position and a fourth switch position. When the hydraulic valve is in the third switch position, the hydraulic valve is in a disconnected state, and the valve is in the first switch position. When the hydraulic valve is in the fourth switch position, the hydraulic valve is in a conducting state, and the valve can be switched from the first switch position to the second switch position when the hydraulic valve is in the conducting state. The high-pressure hydraulic pump and the low-pressure hydraulic pump are driven by a common drive unit; The outlet side of the high-pressure hydraulic pump is connected to the first connector of the valve through a first pressure pipeline and connected to the high-pressure circuit through a second pressure pipeline connected to the first pressure pipeline, and a one-way valve is provided in the second pressure pipeline; The outlet side of the low-pressure hydraulic pump is connected to the second connector of the valve via a third pressure line and is connected to the low-pressure circuit via a fourth pressure line connected to the third pressure line; When the valve is in the first switch position, the first connector and the second connector are closed, and the first pressure line and the third pressure line are disconnected; when the valve is in the second switch position, the first connector and the second connector are connected, and the first pressure line and the third pressure line are connected.

2. The hydraulic system according to claim 1, characterized in that: The drive unit is a motor controlled by the TCU.

3. The hydraulic system according to claim 1, characterized in that: At least one of the inlet side of the high-pressure hydraulic pump, the inlet side of the low-pressure hydraulic pump, and the inlet side of the one-way valve is provided with a filter element.

4. The hydraulic system according to claim 1, characterized in that: The second pressure pipeline is also connected in parallel with an accumulator.

5. An automatic transmission, characterized in that: Comprising the hydraulic system as claimed in any one of claims 1 to 4.

6. A car, characterized in that: Comprising the automatic transmission as claimed in claim 5.

Images