A hydraulic control system for a gear direct-drive continuously variable transmission

Abstract

This invention discloses a hydraulic control system for a gear-driven continuously variable transmission (CVT), including a manual directional valve and a control valve section. The manual directional valve has first and second working positions, corresponding to forward and reverse gears, respectively. In the first working position, when the vehicle speed is lower than a preset speed, the first clutch and shift fork are activated, and the input and output shafts of the transmission are driven by gears. In the first working position, when the vehicle speed is higher than the preset speed, the second clutch is activated, and the input and output shafts are driven by a steel belt. In the third working position, the third clutch and shift fork are activated, and the input and output shafts are driven by gears. This invention also provides a control method for a gear-driven CVT. The hydraulic control system and control method of this invention support the use of gear transmission in gear-driven CVTs during start-up and at low speeds, improving the problems of slow start-up response and poor low-speed transmission efficiency in traditional CVTs.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology for transmissions, and more specifically to a hydraulic control system for a gear direct-drive continuously variable transmission (CVT). Background Technology

[0002] As a core component of the transmission system, the main function of the transmission is to achieve efficient power transmission and sensitive shift response.

[0003] Traditional continuously variable transmissions (CVTs) use steel belt drives, which result in low transmission efficiency and slow start-up response at low speeds. In contrast, gear direct-drive CVTs use both gear and steel belt drives. Gear drives can be used for start-up and at low vehicle speeds, effectively improving start-up response and transmission efficiency.

[0004] There is an urgent need in this field for a control system that supports gear direct-drive continuously variable transmissions. Summary of the Invention

[0005] The purpose of this invention is to provide a hydraulic control system for a gear direct-drive continuously variable transmission (CVT) that supports the use of gear transmission at low speeds, thereby improving start-up response and low-speed transmission efficiency.

[0006] To solve the above-mentioned technical problems, the present invention provides a hydraulic control system for a gear direct-drive continuously variable transmission (CVT), including a manual directional valve and a control valve section. The manual directional valve includes a first working position and a second working position, corresponding to forward gear and reverse gear, respectively, wherein:

[0007] When the manual reversing valve is in the first working position and the vehicle speed is lower than the preset vehicle speed, the control valve controls the first clutch and shift fork to be in the engaged position, and the input shaft and output shaft of the gear direct drive continuously variable transmission are driven by gears.

[0008] When the manual reversing valve is in the first working position and the vehicle speed is higher than the preset vehicle speed, the control valve controls the second clutch to be in the engaged position, and the input shaft and the output shaft are driven by a steel belt.

[0009] When the manual reversing valve is in the second working position, the control valve controls the third clutch and shift fork to be in the engaged position, and the input shaft and the output shaft are driven by gears.

[0010] The hydraulic control system of this invention uses a manual directional valve to switch the gears of the transmission and a control valve to switch the transmission mode of the transmission. This allows the transmission to use gears for transmission when the vehicle starts and at low speeds, and to use a steel belt for transmission at high speeds, thus improving the problems of poor start-up response and low-speed transmission efficiency of traditional continuously variable transmissions.

[0011] Optionally, the main oil circuit includes a first branch, the first port of the manual directional valve is connected to the first branch, and the second port is connected to the oil tank. The control valve section includes:

[0012] The first solenoid valve is connected to the third oil port of the manual directional valve, and its output end is connected to the first clutch.

[0013] The second solenoid valve is connected to the third oil port of the manual directional valve, and its output end is connected to the second clutch.

[0014] The third solenoid valve is connected to the first branch;

[0015] The reversing valve has its first oil port connected to the output end of the third solenoid valve, its second oil port connected to the fourth oil port of the manual reversing valve, its third oil port connected to the third clutch, and its fourth oil port connected to the shift fork. When it is in the first working position, its first oil port and third oil port are connected, and its second oil port and fourth oil port are connected; when it is in the second working position, its first oil port and fourth oil port are connected, and its second oil port and third oil port are connected.

[0016] When the manual reversing valve is in the first working position, its first oil port is connected to the third oil port, and its second oil port is connected to the fourth oil port; when it is in the second working position, its first oil port is connected to the fourth oil port, and its second oil port is connected to the third oil port.

[0017] The controller is used to adjust the output pressure of the first solenoid valve, the second solenoid valve, and the third solenoid valve according to the vehicle's operating status.

[0018] Optionally, the first oil port of the first solenoid valve is connected to the third oil port of the manual directional valve, the first control end of the directional valve is a spring end, and the second control end is connected to the first oil port of the first solenoid valve.

[0019] Optionally, it also includes a mechanical pump, the outlet of which is connected to the main oil circuit.

[0020] Optionally, it also includes flow rate regulating components, which are respectively disposed between the third oil port of the reversing valve and the third clutch, between the first solenoid valve and the first clutch, and between the second solenoid valve and the second clutch, to reduce the depressurization rate of the first clutch, the second clutch and the third clutch.

[0021] Optionally, the flow rate regulating component includes two parallel oil passages, one of which is equipped with a check valve to ensure that hydraulic oil can only flow in one direction to the first clutch, the second clutch, and the third clutch, and the other oil passage is equipped with a throttle orifice.

[0022] Optionally, it also includes a pressure reducing valve, whose first oil port is connected to the main oil circuit, the second oil port is connected to the oil tank, the third oil port is connected to the first branch circuit, and the first control end is a spring end, and the second control end is connected to the first branch circuit.

[0023] When in the first working position, its first oil port is connected to its third oil port; when in the second working position, its second oil port is connected to its third oil port.

[0024] Optionally, it also includes a throttle orifice disposed in the main oil circuit and a flow regulating valve, wherein the flow regulating valve can adjust the flow rate of the main oil circuit to a preset value according to the pressure difference between the inlet and outlet of the throttle orifice.

[0025] Optionally, the oil inlet of the flow regulating valve is connected to the oil outlet of the mechanical pump, the oil outlet is connected to the oil tank, the first control end is a spring end and is also connected to the outlet of the throttle orifice, and the second control end is connected to the inlet of the throttle orifice.

[0026] When the flow regulating valve is in the first working position, its oil inlet and oil outlet are separated; when it is in the second working position, its oil inlet and oil outlet are connected.

[0027] Optionally, the main oil circuit further includes a second branch and a third branch, the second branch being connected to the driven oil cylinder, and the third branch being connected to the driving oil cylinder, and further includes:

[0028] An active pressure regulating valve is installed on the third branch to regulate the hydraulic oil pressure entering the active cylinder;

[0029] A driven pressure regulating valve is installed on the second branch and is used to regulate the hydraulic oil pressure entering the driven cylinder.

[0030] Optionally, it also includes:

[0031] The fourth solenoid valve is connected to the first branch, and its output end is connected to the first control end of the driven pressure regulating valve. The second control end of the driven pressure regulating valve is a spring end, and it is also connected to the oil circuit between the driven pressure regulating valve and the driven oil cylinder.

[0032] The controller is also used to regulate the output pressure of the fourth solenoid valve.

[0033] Optionally, it also includes:

[0034] The fifth solenoid valve is connected to the first branch, and its output end is connected to the first control end of the active pressure regulating valve. The second control end of the active pressure regulating valve is a spring end, and it is also connected to the oil circuit connecting the active pressure regulating valve and the active cylinder.

[0035] The controller is also used to regulate the output pressure of the fifth solenoid valve.

[0036] Optionally, it also includes:

[0037] A comparator valve connects the output terminals of the fourth solenoid valve and the fifth solenoid valve;

[0038] The main oil circuit pressure regulating valve has an inlet connected to the main oil circuit and an outlet connected to the secondary oil circuit. The first control end is a spring end and is also connected to the main oil circuit. The second control end is connected to the comparison valve. Under normal conditions, the inlet and outlet of the main oil circuit pressure regulating valve are isolated.

[0039] Optionally, it also includes:

[0040] Electric pump;

[0041] An electronic pump switching valve is provided, wherein the oil inlet of the electronic pump switching valve is connected to the oil outlet of the electronic pump, the first oil outlet is connected to the pressure reducing valve and the driven pressure regulating valve through a check valve, the second oil outlet is connected to the first cooling and lubrication branch, and the first control end of the electronic pump switching valve is a spring end, and the second control end is connected to the main oil circuit.

[0042] When the electronic pump switching valve is in the first working position, its oil inlet is connected to the first oil outlet; when it is in the second working position, its oil inlet is connected to the second oil outlet.

[0043] Optionally, it also includes:

[0044] The torque converter reversing valve has a first oil port connected to the secondary oil circuit, a second oil port connected to the oil tank, a third oil port connected to the locking chamber of the hydraulic torque converter, a fourth oil port connected to the second cooling and lubrication branch, and a fifth oil port connected to the unlocking chamber of the hydraulic torque converter.

[0045] The torque converter pressure regulating valve has a first oil port connected to the first branch, a second oil port connected to the sixth oil port of the torque converter reversing valve, and a third oil port connected to the oil tank. When it is in the first working position, its second oil port and third oil port are connected; when it is in the second working position, its first oil port and second oil port are connected.

[0046] When the torque converter directional valve is in the unlocked position, the third oil port and the fourth oil port of the torque converter directional valve are connected, and the first oil port and the fifth oil port are connected; when the torque converter directional valve is in the locked position, the sixth oil port of the torque converter directional valve is connected to the third oil port, the first oil port and the fourth oil port are connected, and the fifth oil port and the second oil port are connected.

[0047] Optionally, it also includes:

[0048] The sixth solenoid valve is connected to the first branch, and its output end is connected to the first control end of the torque converter directional valve and the first control end of the torque converter pressure regulating valve.

[0049] The second control terminal of the torque converter reversing valve is a spring terminal;

[0050] The second control end of the torque converter pressure regulating valve is a spring end, and it is also connected to the second oil port of the torque converter pressure regulating valve;

[0051] The controller is also used to regulate the output pressure of the sixth solenoid valve.

[0052] Optionally, it also includes an oil cooler, a filter press and a nozzle connected in sequence. The first cooling and lubrication branch and the second cooling and lubrication branch are both equipped with one-way valves and converge at the oil cooler so that the hydraulic oil converges unidirectionally at the oil cooler.

[0053] Optionally, it also includes a safety valve, which is respectively disposed between the third branch, the main oil circuit pressure regulating valve and the torque converter reversing valve, and between the electronic pump and the electronic pump switching valve. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of a gear direct-drive continuously variable transmission (CVT).

[0055] Figure 2 for Figure 1 The transmission path of a gear-driven continuously variable transmission (CVT) during gear transmission.

[0056] Figure 3 for Figure 1 The transmission path of a gear-driven continuously variable transmission (CVT) in the case of steel belt drive;

[0057] Figure 4 This is a schematic diagram of the hydraulic control system of the gear direct drive continuously variable transmission provided by the present invention;

[0058] in, Figures 1-4 The annotations in the attached figures are explained as follows:

[0059] 1-Manual directional valve; 2-Mechanical pump; 3-First solenoid valve; 4-Second solenoid valve; 5-Third solenoid valve; 6-Directional valve; 7-Flow rate regulating component; 8-Pressure reducing valve; 9-Active pressure regulating valve; 10-Driven pressure regulating valve; 11-Fourth solenoid valve; 12-Fifth solenoid valve; 13-Comparison valve; 14-Main oil circuit pressure regulating valve; 15-Electronic pump; 16-Electronic pump switching valve; 17-Torque converter directional valve; 18-Torque converter pressure regulating valve; 19-Sixth solenoid valve; 20-Oil cooler; 21-Filter press; 22-Nozzle; 23-Flow regulating valve; 24-Safety valve;

[0060] A - Main fuel line; A1 - First branch line; A2 - Second branch line; A3 - Third branch line;

[0061] B - Secondary oil circuit; C1 - First cooling and lubrication branch; C2 - Second cooling and lubrication branch;

[0062] 01-First clutch; 02-Shift fork; 03-Second clutch; 04-Third clutch; 05-Driven cylinder; 06-Driven cylinder; 07-Torque converter; 071-Lock-in chamber; 072-Unlock-in chamber;

[0063] I - Input axis; O - Output axis. Detailed Implementation

[0064] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0065] The terms "first" and "second" used in this article are used only for the convenience of describing two or more structures or components that are identical or similar in structure and / or function, and do not indicate any special limitation on order and / or importance.

[0066] Please refer to the following first. Figures 1 to 3 , Figure 1 This is a schematic diagram of a gear direct-drive continuously variable transmission (CVT).

[0067] Figure 2 for Figure 1 The transmission path of a gear-driven continuously variable transmission (CVT) during gear transmission. Figure 3 for Figure 1 The transmission path of a gear direct-drive continuously variable transmission (CVT) when driven by a steel belt.

[0068] This gear-driven continuously variable transmission (CVT) not only has the steel belt drive structure of a traditional CVT, but also has an additional gear drive structure, such as... Figure 2 As shown, during gear transmission, the first clutch 01 or the third clutch 04 is engaged, and the shift fork 02 needs continuous oil pressure to remain in the engaged position, while the second clutch 03 is disengaged; during steel belt transmission, the second clutch 03 is engaged, the shift fork 02 is depressurized and reset, and the first clutch 01 and the third clutch 04 are disengaged.

[0069] Based on this, the present invention provides a hydraulic control system that supports the switching of the above-mentioned gear direct drive continuously variable transmission in two transmission modes, which will be described in detail below.

[0070] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the hydraulic control system of a gear direct-drive continuously variable transmission provided by the present invention.

[0071] This invention provides a hydraulic control system for a gear-driven continuously variable transmission (CVT), including a manual directional valve 1 and a control valve section. The manual directional valve 1 includes a first working position and a second working position, corresponding to forward gear and reverse gear, respectively.

[0072] When the manual reversing valve 1 is in the first working position and the vehicle speed is lower than the preset vehicle speed, the control valve section controls the first clutch 01 and the shift fork 02 to be in the engaged position, and the input shaft I and output shaft O of the gear direct drive continuously variable transmission are driven by gears.

[0073] When the manual reversing valve 1 is in the first working position and the vehicle speed is higher than the preset vehicle speed, the control valve section controls the second clutch 03 to be in the engaged position, and the input shaft I and the output shaft O are driven by a steel belt.

[0074] When the manual directional valve 1 is in the second working position, the control valve section controls the third clutch 04 and the shift fork 02 to be in the engaged position, and the input shaft I and the output shaft O are driven by gears.

[0075] The hydraulic control system of this invention uses a manual directional valve 1 to switch the gears of the transmission and a control valve to switch the transmission mode of the transmission. This allows the transmission to use gears for transmission when the vehicle starts and at low speeds, and to use a steel belt for transmission at high speeds, thus improving the problems of poor start-up response and low-speed transmission efficiency of traditional continuously variable transmissions.

[0076] The manual directional valve 1 also includes a third working position and a fourth working position, which correspond to neutral and parking gear respectively. Since in actual applications, the gear shifting of the transmission is usually in the order of forward gear, neutral gear, reverse gear, and parking gear, the working positions of the manual directional valve 1 are arranged in the following order: first working position, third working position, second working position, and fourth working position.

[0077] Specifically, the main oil circuit A includes a first branch A1, the first port of the manual directional valve 1 is connected to the first branch A1, and the second port is connected to the oil tank. The control valve section includes:

[0078] The first solenoid valve 3 has its first oil port connected to the third oil port of the manual directional valve 1, its second oil port connected to the oil tank, and its third oil port connected to the first clutch 01. In the first working position, the first oil port and the third oil port are connected; in the second working position, the second oil port and the third oil port are connected, and the third oil port is the output end.

[0079] The second solenoid valve 4 has its first oil port connected to the third oil port of the manual directional valve 1, its second oil port connected to the oil tank, and its third oil port connected to the second clutch 03. In the first working position, the first oil port and the third oil port are connected; in the second working position, the second oil port and the third oil port are connected, and the third oil port is the output end.

[0080] The third solenoid valve 5 has its first oil port connected to the first branch A1 and its second oil port connected to the oil tank.

[0081] The reversing valve 6 has its first oil port connected to the third oil port of the third solenoid valve 5, its second oil port connected to the fourth oil port of the manual reversing valve 1, its third oil port connected to the third clutch 04, and its fourth oil port connected to the shift fork 02. When it is in the first working position, its first oil port and third oil port are connected, and its second oil port and fourth oil port are connected. When it is in the second working position, its first oil port and fourth oil port are connected, and its second oil port and third oil port are connected. The third oil port of the third solenoid valve 5 is the output end.

[0082] The controller is used to adjust the output pressure of the first solenoid valve 3, the second solenoid valve 4, and the third solenoid valve 5, i.e., the third oil port, according to the vehicle's operating status.

[0083] When the manual directional valve 1 is in the first working position, its first oil port is connected to the third oil port, and its second oil port is connected to the fourth oil port; when the manual directional valve 1 is in the second working position, its first oil port is connected to the fourth oil port, and its second oil port is connected to the third oil port.

[0084] Here, the vehicle operating status includes oil temperature signal, speed ratio change, engine speed, etc., which can be comprehensively set according to specific needs in actual applications.

[0085] Based on the above arrangement, during low-speed driving, the manual directional valve 1 can be controlled to be in the first working position, and the controller can control the first solenoid valve 3 to be in the first working position, the second solenoid valve 4 to be in the second working position, the directional valve 6 to be in the second working position, and the third solenoid valve 5 to be in the first working position. At this time, the first clutch 01 and the shift fork 02 are both connected to the oil outlet of the mechanical pump 2, and the first clutch 01 and the shift fork 02 are switched to the engaged position. The second clutch 03 and the third clutch 04 are both connected to the oil tank, and the second clutch 03 and the third clutch 04 are switched to the disengaged position. Thus, the input shaft I and the output shaft O of the transmission are driven by gears, improving the transmission efficiency.

[0086] During high-speed driving, the manual directional valve 1 is controlled to be in the first working position, and the first solenoid valve 3 is controlled to be in the second working position, the second solenoid valve 4 is in the first working position, the directional valve 6 is in the second working position, and the third solenoid valve 5 is in the second working position. At this time, the second clutch 03 is connected to the oil outlet of the mechanical pump 2 and the second clutch 03 is switched to the engaged position. The first clutch 01, shift fork 02, and third clutch 04 are all connected to the oil tank and the first clutch 01, shift fork 02, and third clutch 04 are all switched to the disengaged position. The input shaft I and output shaft O of the transmission are driven by a steel belt.

[0087] When reversing, the manual directional valve 1 is in the second working position, the directional valve 6 is in the first working position, and the third solenoid valve 5 is in the first working position. At this time, the third clutch 04 and the shift fork 02 are connected to the oil outlet of the mechanical pump 2. The third clutch 04 and the shift fork 02 are switched to the engaged position. The first clutch 01 and the second clutch 03 are connected to the oil tank. The first clutch 01 and the second clutch 03 are switched to the disengaged position. The input shaft I and the output shaft O of the transmission are driven by gears.

[0088] In this embodiment, reliable interaction of shift modes is achieved through manual directional valve 1, three solenoid valves and directional valve 6.

[0089] Furthermore, in this embodiment, the first control end of the directional valve 6 is a spring end, and the second control end is connected to the first oil port of the first solenoid valve 3. Therefore, the switching of the working position of the directional valve 6 is determined by the spring force and the input pressure of the first oil port of the first solenoid valve 3. Figure 4 As shown, when the manual directional valve 1 is in the first working position, i.e., the vehicle is in forward gear, the first oil port of the first solenoid valve 3 is connected to the first branch A1, the spring force at the left end of the directional valve 6 is less than the control pressure at the right end, the directional valve 6 switches to the second working position, the third clutch 04 is disconnected, and the shift fork 02 is controlled by the third solenoid valve 5; when the manual directional valve 1 is in the second working position, i.e., the vehicle is in reverse gear, the first oil port of the first solenoid valve 3 is connected to the oil tank, the spring force at the left end of the directional valve 6 is greater than the control pressure at the right end, the directional valve 6 switches to the first working position, the shift fork 02 is directly connected to the first branch A1, and the third clutch 04 is controlled by the third solenoid valve 5.

[0090] Therefore, it can be seen that in forward gear, shift fork 02 is controlled by the third solenoid valve 5, while in reverse gear, shift fork 02 is directly connected to the first branch A1 without a dedicated solenoid valve for control. This is because in forward gear, the transmission needs to switch between gear drive and steel belt drive, so the working position of shift fork 02 needs to be precisely controlled to avoid shock or jerking during gear shift. When the vehicle shifts from forward gear to reverse gear, shift fork 02 usually does not need to switch working positions, but only needs to remain in the engaged position. Therefore, no separate solenoid valve is set to control shift fork 02, making the system simpler.

[0091] Furthermore, the first solenoid valve 3 includes an electromagnetic control end and a spring end, and its spring end is also connected to the third oil port of the first solenoid valve 3. Therefore, the controller can adjust the control pressure of the electromagnetic control end according to the spring force and the output pressure of the third oil port of the first solenoid valve 3, thereby realizing the switching of the working position of the first solenoid valve 3.

[0092] Similarly, the second solenoid valve 4 includes an electromagnetic control end and a spring end, and its spring end is also connected to the third oil port of the second solenoid valve 4. The controller can adjust the control pressure of the electromagnetic control end according to the spring force and the output pressure of the third oil port of the second solenoid valve 4, thereby realizing the switching of the working position of the second solenoid valve 4.

[0093] The third solenoid valve 5 includes an electromagnetic control end and a spring end, and its spring end is also connected to the third oil port of the third solenoid valve 5. The controller can adjust the control pressure of the electromagnetic control end according to the spring force and the output pressure of the third oil port of the third solenoid valve 5, thereby realizing the switching of the working position of the third solenoid valve 5.

[0094] Please continue to refer to this. Figure 4 The hydraulic control system in this embodiment also includes a mechanical pump 2, the oil outlet of which is connected to the main oil circuit A.

[0095] It also includes a flow rate regulating component 7, which is respectively disposed between the third oil port of the reversing valve 6 and the third clutch 04, between the first solenoid valve 3 and the first clutch 01, and between the second solenoid valve 4 and the second clutch 03, so as to reduce the pressure relief speed of the first clutch 01, the second clutch 03 and the third clutch 04.

[0096] Specifically, the flow rate regulating component 7 includes two oil passages arranged in parallel. One oil passage is equipped with a check valve so that the hydraulic oil can only flow in one direction to the first clutch 01, the second clutch 03 and the third clutch 04. The other oil passage is equipped with a throttle orifice.

[0097] With this configuration, during the pressure build-up process, hydraulic oil flows into the first clutch 01, the second clutch 03, or the third clutch 04 simultaneously through two oil circuits, resulting in a fast pressure build-up speed. During the pressure release process, the hydraulic oil can only flow out through the throttle orifice, effectively reducing the pressure release speed and minimizing shift shock.

[0098] Furthermore, it also includes a pressure reducing valve 8, used to reduce the oil pressure in the first branch A1 to a first preset pressure.

[0099] The pressure reducing valve 8 can provide a stable input pressure for the manual directional valve 1, the third solenoid valve 5, and other valves connected to the first branch A1 (which will be explained later). The specific value can be adjusted adaptively according to the requirements.

[0100] Specifically, the first port of the pressure reducing valve 8 is connected to the main oil circuit A, the second port is connected to the oil tank, and the third port is connected to the first branch circuit A1. The first control end of the pressure reducing valve 8 is the spring end, and the second control end is connected to the first branch circuit A1. Therefore, the working position of the pressure reducing valve 8 can be adjusted according to the spring force and the output pressure of the third port of the pressure reducing valve 8.

[0101] When the pressure at the second control end is less than the spring force, that is, when the output pressure of the third port of the pressure reducing valve 8 is less than the spring force, the pressure reducing valve 8 is in the first working position, and its first port and third port are connected. At this time, the main oil circuit and the first branch A1 are connected until the pressure of the first branch A1 reaches the preset pressure. When the pressure at the second control end is greater than the spring force, that is, when the output pressure of the third port of the pressure reducing valve 8 is greater than the spring force, the pressure reducing valve 8 switches from the second working position, and its second port and third port are connected. At this time, the first branch A1 is connected to the oil tank until the pressure of the first branch A1 reaches the preset pressure.

[0102] Furthermore, it also includes a throttle orifice a located in the main oil circuit A, and a flow regulating valve 23. The flow regulating valve 23 can adjust the flow rate of the main oil circuit A to a preset value according to the pressure difference between the inlet and outlet of the throttle orifice a, so as to ensure the stability of the system flow rate.

[0103] Specifically, the inlet of the flow regulating valve 23 is connected to the outlet of the mechanical pump 2, and the outlet is connected to the oil tank. The first control end is a spring end, which is also connected to the outlet of the throttle orifice a. The second control end is connected to the inlet of the throttle orifice a. Therefore, the working position of the flow regulating valve 23 can be adjusted according to the spring force and the pressure difference between the inlet and outlet of the throttle orifice a.

[0104] When the pressure difference between the inlet and outlet of throttle orifice a is greater than the spring force, that is, when the hydraulic oil flow rate in the main oil circuit A is greater than the limit value, the flow regulating valve 23 is in the second working position, and its inlet and outlet are connected. Excess hydraulic oil will return to the oil tank to ensure the stability of the system flow rate. When the pressure difference between the inlet and outlet of throttle orifice a is greater than the spring force, that is, when the hydraulic oil flow rate in the main oil circuit A is less than the limit value, the flow regulating valve 23 is in the first working position, and its inlet and outlet are disconnected.

[0105] Please continue to refer to this. Figure 4 The main oil circuit A also includes a second branch A2 and a third branch A3. The second branch A2 is connected to the oil inlet of the driven cylinder 05, and the third branch A3 is connected to the oil inlet of the driving cylinder 06. It also includes:

[0106] Active pressure regulating valve 9 is installed on the third branch A3 and is used to regulate the hydraulic oil pressure entering the active oil cylinder 06;

[0107] The driven pressure regulating valve 10 is installed on the second branch A2 and is used to regulate the hydraulic oil pressure entering the driven oil cylinder 05.

[0108] Among them, the active cylinder 06 and the driven cylinder 05 are used to clamp the metal strip, and the speed ratio is changed by adjusting the pressure ratio between the two; the above configuration allows for separate control of the pressure of the active cylinder 06 and the driven cylinder 05, providing good flexibility.

[0109] Furthermore, it also includes a fourth solenoid valve 11, whose first oil port is connected to the first branch A1, the second oil port is connected to the oil tank, and the third oil port, i.e. the output end, is connected to the first control end of the driven pressure regulating valve 10. The second control end of the driven pressure regulating valve 10 is the spring end, and it is also connected to the oil circuit between the driven pressure regulating valve 10 and the driven oil cylinder 05.

[0110] The controller is also used to regulate the output pressure of the fourth solenoid valve 11.

[0111] Therefore, the working position switching of the driven pressure regulating valve 10 is controlled by the output pressure of the third port of the fourth solenoid valve 11, the spring force, and the feedback pressure of the driven cylinder 05.

[0112] Specifically, the first oil port of the driven pressure regulating valve 10 is connected to the second branch A2, the second oil port is connected to the oil tank, and the third oil port is connected to the driven oil cylinder 05. In the first working position, the first oil port and the third oil port are connected; in the second working position, the third oil port and the second oil port are connected.

[0113] After the above settings are configured, the pressure of the driven cylinder 05 is jointly controlled by the fourth solenoid valve 11 and the driven pressure regulating valve 10, so as to... Figure 4 As shown, the left end of the driven pressure regulating valve 10 is subjected to the output pressure of the third port of the fourth solenoid valve 11, and the right end is subjected to the spring force and the feedback pressure of the driven cylinder 05. When the pressure of the driven cylinder 05 is lower than the target pressure, the controller adjusts the output pressure of the third port of the fourth solenoid valve 11 to switch the driven pressure regulating valve 10 to the first working position. The first port and the third port of the driven pressure regulating valve 10 are connected. At this time, the driven cylinder 05 is connected to the second branch A2 until the pressure of the driven cylinder 05 reaches the target pressure.

[0114] When the pressure of the driven cylinder 05 is higher than the target pressure, the controller adjusts the output pressure of the third port of the fourth solenoid valve 11 so that the driven pressure regulating valve 10 switches to the second working position. The second and third ports of the driven pressure regulating valve 10 are connected. At this time, the driven cylinder 05 is connected to the oil tank to reduce the pressure of the driven cylinder 05 until the pressure of the driven cylinder 05 reaches the target pressure.

[0115] Similarly, it also includes a fifth solenoid valve 12, whose first oil port is connected to the first branch A1, the second oil port is connected to the oil tank, and the third oil port, i.e. the output end, is connected to the first control end of the active pressure regulating valve 9. The second control end of the active pressure regulating valve 9 is the spring end, and it is also connected to the oil circuit connecting the active pressure regulating valve 9 and the active oil cylinder 06.

[0116] The controller is also used to regulate the output pressure of the fifth solenoid valve 12.

[0117] Therefore, the working position switching of the active pressure regulating valve 9 is controlled by the output pressure of the third oil port of the fifth solenoid valve 12, the spring force, and the feedback pressure of the active oil cylinder 06.

[0118] Specifically, the first oil port of the active pressure regulating valve 9 is connected to the third branch A3, the second oil port is connected to the oil tank, and the third oil port is connected to the active oil cylinder 06. In the first working position, the first oil port and the third oil port are connected; in the second working position, the third oil port and the second oil port are connected.

[0119] After the above settings are configured, the pressure of the active hydraulic cylinder 06 is jointly controlled by the fifth solenoid valve 12 and the active pressure regulating valve 9. Figure 4 As shown, the left end of the active pressure regulating valve 9 is subjected to the output pressure of the third port of the fifth solenoid valve 12, and the right end is subjected to the spring force and the feedback pressure of the active cylinder 06. When the pressure of the active cylinder 06 is lower than the target pressure, the controller adjusts the output pressure of the third port of the fifth solenoid valve 12 to switch the active pressure regulating valve 9 to the first working position. The first port and the third port of the active pressure regulating valve 9 are connected. At this time, the active cylinder 06 is connected to the third branch A3 until the pressure of the active cylinder 06 reaches the target pressure.

[0120] When the pressure of the active cylinder 06 is higher than the target pressure, the controller adjusts the output pressure of the third port of the fifth solenoid valve 12 so that the active pressure regulating valve 9 switches to the second working position. The second and third ports of the active pressure regulating valve 9 are connected. At this time, the active cylinder 06 is connected to the oil tank to reduce the pressure of the active cylinder 06 until the pressure of the active cylinder 06 reaches the target pressure.

[0121] Please continue to refer to this. Figure 4 The hydraulic control system of the present invention further includes:

[0122] Comparison valve 13 connects the third oil port of the fourth solenoid valve 11 and the output port of the fifth solenoid valve 12;

[0123] The main oil circuit pressure regulating valve 14 has its inlet connected to the main oil circuit A and its outlet connected to the secondary oil circuit B. The first control end is a spring end and is also connected to the main oil circuit A. The second control end is connected to the comparison valve 13. Under normal conditions, the inlet and outlet of the main oil circuit pressure regulating valve 14 are isolated.

[0124] Since the driving cylinder 06 and driven cylinder 05 in the system require the highest pressure, the output pressure of the third port of the fourth solenoid valve 11 and the output pressure of the third port of the fifth solenoid valve 12 are compared. The larger one is applied to the main oil circuit pressure regulating valve 14 so that the pressure of the main oil circuit A is slightly greater than the maximum pressure required by the actuator. When the pressure of the main oil circuit A reaches the target pressure, the excess hydraulic oil can enter the secondary oil circuit B to control the hydraulic torque converter 07 or to cool and lubricate it.

[0125] The pressure of the main oil circuit A is controlled by the comparison valve 13 and the main oil circuit pressure regulating valve 14. The structure is simple and ensures the pressure of the main oil circuit A is stable.

[0126] Furthermore, it also includes an electronic pump 15 and an electronic pump switching valve 16. The oil inlet of the electronic pump switching valve 16 is connected to the oil outlet of the electronic pump 15. The first oil outlet is connected to the pressure reducing valve 8 and the driven pressure regulating valve 10 through a check valve. The second oil outlet is connected to the first cooling and lubrication branch C1. The first control end of the electronic pump switching valve 16 is a spring end, and the second control end is connected to the main oil circuit A.

[0127] When the electronic pump switching valve 16 is in the first working position, its oil inlet is connected to the first oil outlet; when it is in the second working position, its oil inlet is connected to the second oil outlet.

[0128] Therefore, the operating position of the electronic pump switching valve 16 can be switched according to the spring force and the pressure of the main oil circuit A, specifically:

[0129] When the pressure at the second control end is less than the spring force, i.e. when the vehicle starts and the speed is low, the mechanical pump 2 has not yet built up pressure, and the pressure in the main oil circuit A is less than the spring force, the oil inlet of the electronic pump switching valve 16 is connected to the first oil outlet. The electronic pump 15 provides flow to the pressure reducing valve 8 through the check valve, and at the same time provides basic clamping force to the driven cylinder 05 through the driven pressure regulating valve 10. When the pressure at the second control end is greater than the spring force, i.e. after the mechanical pump 2 has built up pressure, the pressure in the main oil circuit A is greater than the spring force, the oil inlet of the electronic pump switching valve 16 is connected to the second oil outlet, and the flow of the electronic pump 15 is switched to the first cooling and lubrication branch C1, which only performs cooling and lubrication. The lubrication flow can be adjusted by controlling the speed of the electronic pump 15.

[0130] Furthermore, the hydraulic control system of the present invention also includes:

[0131] The torque converter reversing valve 17 has its first oil port connected to the secondary oil circuit B, its second oil port connected to the oil tank, its third oil port connected to the locking chamber 071 of the hydraulic torque converter, its fourth oil port connected to the second cooling and lubrication branch C2, and its fifth oil port connected to the unlocking chamber 072 of the hydraulic torque converter.

[0132] The torque converter pressure regulating valve 18 has its first oil port connected to the first branch A1, its second oil port connected to the sixth oil port of the torque converter reversing valve 17, and its third oil port connected to the oil tank. When it is in the first working position, its second oil port and third oil port are connected; when it is in the second working position, its first oil port and second oil port are connected.

[0133] Torque converter directional valve 17 is in the unlocked or locked position:

[0134] When the torque converter directional valve 17 is in the unlocked position, the third port and the fourth port of the torque converter directional valve 17 are connected, and the first port and the fifth port are connected, combined with Figure 4Under this condition, the hydraulic oil in the secondary oil circuit B enters the unlocking chamber 072 of the hydraulic torque converter through the first oil port, flows through the locking chamber 071 of the hydraulic torque converter, and then enters the second cooling and lubrication branch C2.

[0135] When the torque converter directional valve 17 is in the locked position, the sixth port of the torque converter directional valve 17 is connected to the third port, the first port is connected to the fourth port, and the fifth port is connected to the second port. Figure 4 Under this condition, the hydraulic oil in the secondary oil circuit B directly enters the second cooling and lubrication branch C2, the locking chamber 071 of the hydraulic torque converter is connected to the second oil port of the torque converter pressure regulating valve 18, and the unlocking chamber 072 of the hydraulic torque converter is connected to the oil tank.

[0136] When the hydraulic torque converter 07 is in the lock-up state, its lock-up pressure is controlled by the torque converter pressure regulating valve 18. Specifically: when the lock-up pressure of the hydraulic torque converter 07 is lower than the target pressure, the torque converter pressure regulating valve 18 can be controlled to the second working position, with its first and second oil ports connected. At this time, the lock-up chamber 071 of the hydraulic torque converter is connected to the first branch A1 until the lock-up pressure of the hydraulic torque converter 07 reaches the target pressure. When the lock-up pressure of the hydraulic torque converter 07 is greater than the target pressure, the torque converter pressure regulating valve 18 can be controlled to the first working position, with its third and second oil ports connected. At this time, the lock-up chamber 071 of the hydraulic torque converter is connected to the oil tank to reduce the lock-up pressure until the lock-up pressure of the hydraulic torque converter 07 reaches the target pressure.

[0137] Furthermore, it also includes:

[0138] The sixth solenoid valve 19 has its first oil port connected to the first branch A1, its second oil port connected to the oil tank, and its third oil port, i.e. the output end, connected to the first control end of the torque converter reversing valve 17 and the first control end of the torque converter pressure regulating valve 18, respectively.

[0139] The second control end of the torque converter reversing valve 17 is the spring end, that is, the working position switching of the torque converter reversing valve 17 is controlled by the spring force and the output pressure of the third oil port of the sixth solenoid valve 19.

[0140] The second control end of the torque converter pressure regulating valve 18 is a spring end, and it is also connected to the second oil port of the torque converter pressure regulating valve 18. That is, the working position switching of the torque converter pressure regulating valve 18 is controlled by the spring force, the output pressure of the third oil port of the sixth solenoid valve 19, and the lock-up pressure.

[0141] The sixth solenoid valve 19 enables dynamic control of both the torque converter directional valve 17 and the torque converter pressure regulating valve 18.

[0142] Please continue to refer to this. Figure 4Both the first cooling and lubrication branch C1 and the second cooling and lubrication branch C2 are equipped with one-way valves. The hydraulic oil from the first cooling and lubrication branch C1 and the second cooling and lubrication branch C2 is collected in the oil cooler 20 and then sequentially filtered by the filter 21 and the nozzle 22 to lubricate the steel belt, clutch and other components.

[0143] In addition, a safety valve 24 is included, which is respectively installed between the third branch A3, the main oil circuit pressure regulating valve 14 and the torque converter reversing valve 17, and between the electronic pump 15 and the electronic pump switching valve 16. When the system pressure is abnormal, the pressure can be released through the safety valve 24.

[0144] The hydraulic control system of a gear direct-drive continuously variable transmission (CVT) provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make several improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A hydraulic control system for a gear direct-drive continuously variable transmission, characterized in that, Includes a manual directional valve (1) and a control valve section. The manual directional valve (1) includes a first working position and a second working position, corresponding to forward gear and reverse gear, respectively. When the manual reversing valve (1) is in the first working position and the vehicle speed is lower than the preset vehicle speed, the control valve controls the first clutch (01) and shift fork (02) to be in the engaged position, and the input shaft (I) and output shaft (O) of the gear direct drive continuously variable transmission are driven by gears. When the manual reversing valve (1) is in the first working position and the vehicle speed is higher than the preset vehicle speed, the control valve controls the second clutch (03) to be in the engaged position, and the input shaft (I) and the output shaft (O) are driven by a steel belt. When the manual reversing valve (1) is in the second working position, the control valve controls the third clutch (04) and the shift fork (02) to be in the engaged position, and the input shaft (I) and the output shaft (O) are driven by gears; The main oil circuit (A) includes a branch circuit (A1), the first port of the manual directional valve (1) is connected to the first branch circuit (A1), and the second port is connected to the oil tank. The control valve section includes: The first solenoid valve (3) is connected to the third oil port of the manual reversing valve (1), and its output end is connected to the first clutch (01); The second solenoid valve (4) is connected to the third oil port of the manual reversing valve (1), and its output end is connected to the second clutch (03); The third solenoid valve (5) is connected to the first branch (A1); The reversing valve (6) has its first oil port connected to the output end of the third solenoid valve (5), its second oil port connected to the fourth oil port of the manual reversing valve (1), its third oil port connected to the third clutch (04), and its fourth oil port connected to the shift fork (02). When it is in the first working position, its first oil port and third oil port are connected, and its second oil port and fourth oil port are connected; when it is in the second working position, its first oil port and fourth oil port are connected, and its second oil port and third oil port are connected. When the manual reversing valve (1) is in the first working position, its first oil port is connected to the third oil port, and its second oil port is connected to the fourth oil port; when it is in the second working position, its first oil port is connected to the fourth oil port, and its second oil port is connected to the third oil port. The controller is used to adjust the output pressure of the first solenoid valve (3), the second solenoid valve (4), and the third solenoid valve (5) according to the vehicle's operating status.

2. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 1, characterized in that, The first oil port of the first solenoid valve (3) is connected to the third oil port of the manual reversing valve (1). The first control end of the reversing valve (6) is a spring end, and the second control end is connected to the first oil port of the first solenoid valve (3).

3. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 1, characterized in that, It also includes a mechanical pump (2), the oil outlet of which is connected to the main oil circuit (A).

4. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 1, characterized in that, It also includes a flow rate regulating component (7), which is respectively disposed between the third oil port of the reversing valve (6) and the third clutch (04), between the first solenoid valve (3) and the first clutch (01), and between the second solenoid valve (4) and the second clutch (03) to reduce the pressure relief speed of the first clutch (01), the second clutch (03) and the third clutch (04).

5. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 4, characterized in that, The flow rate regulating component (7) includes two oil circuits arranged in parallel. One of the oil circuits is equipped with a one-way valve so that the hydraulic oil can only flow in one direction to the first clutch (01), the second clutch (03) and the third clutch (04). The other oil circuit is equipped with a throttle orifice.

6. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 1, characterized in that, It also includes a pressure reducing valve (8), whose first oil port is connected to the main oil circuit (A), the second oil port is connected to the oil tank, the third oil port is connected to the first branch (A1), and the first control end is a spring end, and the second control end is connected to the first branch (A1). When in the first working position, its first oil port is connected to its third oil port; when in the second working position, its second oil port is connected to its third oil port.

7. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 3, characterized in that, It also includes a throttle orifice (a) disposed in the main oil circuit (A) and a flow regulating valve (23), which can regulate the flow rate of the main oil circuit (A) to a preset value according to the pressure difference between the inlet and outlet of the throttle orifice (a).

8. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 7, characterized in that, The inlet of the flow regulating valve (23) is connected to the outlet of the mechanical pump (2), the outlet is connected to the oil tank, the first control end is a spring end, and it is also connected to the outlet of the throttle orifice (a), and the second control end is connected to the inlet of the throttle orifice (a). When the flow regulating valve (23) is in the first working position, its oil inlet and oil outlet are separated; when it is in the second working position, its oil inlet and oil outlet are connected.

9. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 6, characterized in that, The main oil circuit (A) further includes a second branch (A2) and a third branch (A3). The second branch (A2) is connected to the driven cylinder (05), and the third branch (A3) is connected to the driving cylinder (06). It also includes: An active pressure regulating valve (9) is installed on the third branch (A3) to regulate the hydraulic oil pressure entering the active cylinder (06); A driven pressure regulating valve (10) is provided on the second branch (A2) for regulating the hydraulic oil pressure entering the driven cylinder (05).

10. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 9, characterized in that, Also includes: The fourth solenoid valve (11) is connected to the first branch (A1), and its output end is connected to the first control end of the driven pressure regulating valve (10). The second control end of the driven pressure regulating valve (10) is a spring end, and it is also connected to the oil circuit between the driven pressure regulating valve (10) and the driven oil cylinder (05). The controller is also used to regulate the output pressure of the fourth solenoid valve (11).

11. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 10, characterized in that, Also includes: The fifth solenoid valve (12) is connected to the first branch (A1), and its output end is connected to the first control end of the active pressure regulating valve (9). The second control end of the active pressure regulating valve (9) is a spring end, and it is also connected to the oil circuit connecting the active pressure regulating valve (9) and the active oil cylinder (06). The controller is also used to regulate the output pressure of the fifth solenoid valve (12).

12. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 11, characterized in that, Also includes: The comparator valve (13) is connected to the output terminals of the fourth solenoid valve (11) and the fifth solenoid valve (12); The main oil circuit pressure regulating valve (14) has an inlet connected to the main oil circuit (A) and an outlet connected to the secondary oil circuit (B). The first control end is a spring end, which is also connected to the main oil circuit (A). The second control end is connected to the comparison valve (13). Under normal conditions, the inlet and outlet of the main oil circuit pressure regulating valve (14) are disconnected.

13. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 12, characterized in that, Also includes: Electronic pump (15); An electronic pump switching valve (16) is provided. The oil inlet of the electronic pump switching valve (16) is connected to the oil outlet of the electronic pump (15). The first oil outlet is connected to the pressure reducing valve (8) and the driven pressure regulating valve (10) through a check valve, so that the hydraulic oil can only flow out from the electronic pump switching valve (16) in one direction. The second oil outlet is connected to the first cooling and lubrication branch (C1). The first control end is a spring end, and the second control end is connected to the main oil circuit (A). When the electronic pump switching valve (16) is in the first working position, its oil inlet is connected to the first oil outlet; when it is in the second working position, its oil inlet is connected to the second oil outlet.

14. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 13, characterized in that, Also includes: The torque converter reversing valve (17) has a first oil port connected to the secondary oil circuit (B), a second oil port connected to the oil tank, a third oil port connected to the locking chamber (071) of the hydraulic torque converter, a fourth oil port connected to the second cooling and lubrication branch (C2), and a fifth oil port connected to the unlocking chamber (072) of the hydraulic torque converter. The torque converter pressure regulating valve (18) has its first oil port connected to the first branch (A1), its second oil port connected to the sixth oil port of the torque converter reversing valve (17), and its third oil port connected to the oil tank. When it is in the first working position, its second oil port is connected to its third oil port; when it is in the second working position, its first oil port and its second oil port are connected. When the torque converter directional valve (17) is in the unlocked position, the third oil port of the torque converter directional valve (17) is connected to the fourth oil port, and the first oil port is connected to the fifth oil port; when the torque converter directional valve (17) is in the locked position, the sixth oil port of the torque converter directional valve (17) is connected to the third oil port, the first oil port is connected to the fourth oil port, and the fifth oil port is connected to the second oil port.

15. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 14, characterized in that, Also includes: The sixth solenoid valve (19) is connected to the first branch (A1), and its output end is connected to the first control end of the torque converter reversing valve (17) and the first control end of the torque converter pressure regulating valve (18). The second control end of the torque converter reversing valve (17) is a spring end; The second control end of the torque converter pressure regulating valve (18) is a spring end, and it is also connected to the second oil port of the torque converter pressure regulating valve (18); The controller is also used to regulate the output pressure of the sixth solenoid valve (19).

16. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 14, characterized in that, It also includes an oil cooler (20), a filter press (21) and a nozzle (22) connected in sequence. The first cooling and lubrication branch (C1) and the second cooling and lubrication branch (C2) are both equipped with check valves so that the hydraulic oil is collected in one direction in the oil cooler (20).

17. The hydraulic control system of the gear direct-drive continuously variable transmission according to claim 14, characterized in that, It also includes a safety valve (24), which is respectively located between the third branch (A3), the main oil circuit pressure regulating valve (14) and the torque converter reversing valve (17), and between the electronic pump (15) and the electronic pump switching valve (16).

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