Hydraulic control system

Abstract

The utility model provides a hydraulic control system. The hydraulic control system comprises an oil pump, a main valve, an upper limit pressure signal valve and a lower limit pressure signal valve. The main valve comprises a main valve first valve position and a main valve second valve position, and the oil pump can be connected to a load to be cooled and / or lubricated through the main valve first valve position or connected to the clutch oil cylinder through the main valve second valve position. The upper limit pressure signal valve comprises an upper limit first valve position and an upper limit second valve position, and the hydraulic control system is configured in the mode that when the pressure of the clutch oil cylinder is larger than preset upper limit pressure, the upper limit second valve position is a working position, the main valve first valve position is switched to the working position, and the oil pump supplies oil to a load. The lower limit pressure signal valve comprises a lower limit first valve position and a lower limit second valve position, and the hydraulic control system is configured in the mode that when the pressure of the clutch oil cylinder is smaller than the preset lower limit pressure, the lower limit second valve position is a working position, the main valve second valve position is switched to the working position, and the oil pump supplies oil to the clutch oil cylinder.

Description

TECHNICAL FIELD

[0001] The present application relates to pressure control of an automotive transmission, in particular to a hydraulic control system. BACKGROUND

[0002] In the field of DHT (Dedicated Hybrid Transmission) technology, the inventor understands a hydraulic control system applying a bi-directional pump, the bi-directional pump builds corresponding oil circuits by forward rotation and reverse rotation respectively. For example, when the bi-directional pump rotates forward, oil is supplied to a cooling lubrication circuit (low pressure); when the bi-directional pump rotates reversely, oil is supplied to a clutch circuit (high pressure). The hydraulic control system is provided with a pressure sensor for detecting oil pressure and a controller for controlling the bi-directional pump. When the clutch is engaged, the oil pressure rises to a set upper limit, the controller controls the bi-directional pump to switch from reverse rotation to forward rotation to supply oil to the cooling lubrication circuit, and the clutch circuit is pressure maintained. When the clutch pressure drops to a set lower limit, the controller controls the bi-directional pump to switch from forward rotation to reverse rotation to supply oil to the clutch, thereby reciprocating.

[0003] However, the hydraulic system has the following disadvantages:

[0004] (1) A bi-directional pump is required, which limits the structure of the pump body, for example, a vane pump with better efficiency and NVH (Noise, Vibration and Harshness) cannot be selected.

[0005] (2) An independent motor is required to drive the oil pump, and the motor needs to have a reverse rotation function;

[0006] (3) Sensors and controllers are required to make pressure determinations and pump controls.

[0007] (4) The above three points also bring disadvantages in cost. INVENTION CONTENTS

[0008] In order to solve or alleviate at least one problem mentioned in the background art, the present application provides a hydraulic control system.

[0009] The hydraulic control system provided by the embodiments of the present application comprises:

[0010] an oil pump;

[0011] a main valve, which is a two-position reversing valve, comprising a main valve first valve position and a main valve second valve position, the oil pump being connectable to a load to be cooled and / or lubricated via the main valve first valve position, and the oil pump being connectable to a clutch cylinder via the main valve second valve position;

[0012] An upper limit pressure signal valve, which is a two-position directional valve including an upper limit first valve position and an upper limit second valve position, the hydraulic control system is configured to: when the pressure of the clutch oil cylinder is greater than a preset upper limit pressure, the upper limit second valve position is in a working position, and the main valve first valve position is switched to a working position, so that the oil pump supplies oil to the load;

[0013] An upper limit pressure signal valve, which is a two-position directional valve including an upper limit first valve position and an upper limit second valve position, the hydraulic control system is configured to: when the pressure of the clutch oil cylinder is greater than a preset upper limit pressure, the upper limit second valve position is in a working position, and the main valve first valve position is switched to a working position, so that the oil pump supplies oil to the load;

[0014] In at least one embodiment, the main valve is a pilot directional valve, which includes:

[0015] A main valve first valve port connected to the oil pump;

[0016] A main valve second valve port connected to the clutch oil cylinder;

[0017] A main valve third valve port connected to the load;

[0018] A main valve pilot cavity, the upper limit pressure signal valve and the lower limit pressure signal valve can change the working position of the main valve by controlling the oil pressure of the main valve pilot cavity, and the oil pump is a one-way pump.

[0019] In at least one embodiment, the hydraulic control system includes a solenoid valve configured to be electrically controlled to change the opening and closing state, the solenoid valve includes:

[0020] An oil inlet connected to the one with greater pressure between the oil pump and the clutch oil cylinder;

[0021] An oil outlet connected to the main valve pilot cavity, thereby being able to change the working position of the main valve through the solenoid valve.

[0022] In at least one embodiment, the hydraulic control system includes a clutch unloading valve, which is a two-position directional valve including an unloading valve first valve position and an unloading valve second valve position, the clutch unloading valve further includes:

[0023] An unloading valve first valve port formed as an unloading port;

[0024] An unloading valve second valve port connected to the clutch oil cylinder,

[0025] An unloading valve pilot cavity, the oil outlet is connected to the unloading valve pilot cavity,

[0026] The hydraulic control system is configured to: when the unloading valve first valve port and the unloading valve second valve port are disconnected when the unloading valve first valve position is in the working position; and when the unloading valve first valve port and the unloading valve second valve port are connected to enable the clutch oil cylinder to be unloaded when the unloading valve second valve position is in the working position.

[0027] In at least one embodiment, a first check valve and a first accumulator are sequentially connected in series between the main valve second valve port and the clutch oil cylinder,

[0028] So that the hydraulic control system is configured to: when the oil outlet does not supply oil to the main valve pilot cavity, and the pressure of the clutch oil cylinder is less than the lower limit pressure, the clutch oil cylinder can gradually accumulate pressure.

[0029] In at least one embodiment, the lower limit pressure signal valve comprises:

[0030] A lower limit first valve port;

[0031] A lower limit second valve port connected to the one of the oil pump and the clutch oil cylinder having greater pressure;

[0032] A lower limit pilot cavity connected to the clutch oil cylinder, when the pressure of the clutch oil cylinder is greater than the lower limit pressure, the lower limit first valve position is in the working position, and the lower limit first valve port is not in communication with the lower limit second valve port,

[0033] So that the hydraulic control system is configured to: when the oil outlet does not supply oil to the main valve pilot cavity, and the pressure of the clutch oil cylinder is greater than the lower limit pressure but does not exceed the upper limit pressure, the clutch oil cylinder can gradually accumulate pressure.

[0034] In at least one embodiment, the upper limit pressure signal valve comprises:

[0035] An upper limit first valve port connected to the main valve pilot cavity;

[0036] An upper limit second valve port connected to the clutch oil cylinder,

[0037] An upper limit pilot cavity connected to the clutch oil cylinder, when the pressure of the clutch oil cylinder is greater than the upper limit pressure, the upper limit second valve position is in the working position, and the upper limit first valve port is in communication with the upper limit second valve port, thereby supplying oil to the main valve pilot cavity,

[0038] So that the hydraulic control system is configured to: when the oil outlet does not supply oil to the main valve pilot cavity, and the pressure of the clutch oil cylinder is greater than the upper limit pressure, the main valve first valve position is switched to the working position.

[0039] In at least one embodiment, a second check valve and a second accumulator are arranged in series between the upper limit first valve port and the main valve pilot chamber,

[0040] The hydraulic control system is configured such that the second accumulator maintains the main valve first valve position at the working position.

[0041] In at least one embodiment, the second check valve is a hydraulic check valve, wherein the hydraulic flow positive direction is from the upper limit first valve port to the main valve pilot chamber, the hydraulic check valve comprises a control port,

[0042] The lower limit pressure signal valve comprises a lower limit first valve port and a lower limit second valve port, the lower limit first valve port is connected to the control port, the control port allows the hydraulic flow in the second check valve to be reversed after being supplied with oil, the lower limit second valve port is connected to the one with greater pressure between the oil pump and the clutch oil cylinder,

[0043] The upper limit pressure signal valve comprises an upper limit third valve port, the upper limit third valve port is a unloading port,

[0044] The hydraulic control system is configured such that when the pressure of the clutch oil cylinder is less than the lower limit pressure, the lower limit second valve position is at the working position, the lower limit first valve port and the lower limit second valve port are in communication, the second check valve allows the hydraulic flow to be reversed, and the second accumulator is unloaded via the upper limit third valve port.

[0045] In at least one embodiment, the hydraulic control system comprises a shuttle valve, an input port of the shuttle valve is connected to the oil pump and the clutch oil cylinder, so that the one with greater pressure between the oil pump and the clutch oil cylinder can be output by the shuttle valve.

[0046] After the clutch enters the engaged state, the pressure regulation is completed by the hydraulic control system, and the clutch pressure fluctuates between the upper and lower limits. During the clutch pressure maintaining stage, the oil pump supplies the load to be cooled and / or lubricated, achieving energy saving. The oil pump does not participate in the reversing, and a simple one-way pump can be used. There is no need for a motor-driven oil pump that can be reversed, and the limitation on the driving source is smaller. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1A A structure schematic diagram of a hydraulic control system according to an embodiment of the present application under the condition of working condition one is shown, and the working condition one is clutch disengagement.

[0048] Figure 1B A clutch oil cylinder pressure change schematic diagram of a hydraulic control system according to an embodiment of the present application under the condition of working condition one is shown.

[0049] Figure 2AFig. 6 shows a schematic diagram of the hydraulic control system according to an embodiment of the application in condition 2, which is the clutch starting to engage - charging process.

[0050] Figure 2B Fig. 7 shows a schematic diagram of the clutch cylinder pressure change of the hydraulic control system according to an embodiment of the application in condition 2.

[0051] Figure 3A Fig. 8 shows a schematic diagram of the hydraulic control system according to an embodiment of the application in condition 3, which is the clutch engaging - continuing charging process.

[0052] Figure 3B Fig. 9 shows a schematic diagram of the clutch cylinder pressure change of the hydraulic control system according to an embodiment of the application in condition 3.

[0053] Figure 4A Fig. 10 shows a schematic diagram of the hydraulic control system according to an embodiment of the application in condition 4, which is the clutch engaging - pressure reaching the upper limit.

[0054] Figure 4B Fig. 11 shows a schematic diagram of the clutch cylinder pressure change of the hydraulic control system according to an embodiment of the application in condition 4.

[0055] Figure 5A Fig. 12 shows a schematic diagram of the hydraulic control system according to an embodiment of the application in condition 5, which is the clutch engaging - pressure slowly decreasing.

[0056] Figure 5B Fig. 13 shows a schematic diagram of the clutch cylinder pressure change of the hydraulic control system according to an embodiment of the application in condition 5.

[0057] Figure 6A Fig. 14 shows a schematic diagram of the hydraulic control system according to an embodiment of the application in condition 6, which is the clutch engaging - pressure reaching the lower limit.

[0058] Figure 6B Fig. 15 shows a schematic diagram of the clutch cylinder pressure change of the hydraulic control system according to an embodiment of the application in condition 6.

[0059] BRIEF DESCRIPTION OF THE DRAWINGS

[0060] 101 oil pump

[0061] 1011 oil storage system

[0062] 1012 suction filter

[0063] 102 load

[0064] 103 clutch cylinder

[0065] 200 main valve

[0066] 201 main valve first valve position

[0067] 202 main valve second valve position

[0068] 211 main valve first valve port

[0069] 212 main valve second valve port

[0070] 213 main valve third valve port

[0071] 221 main valve pilot chamber

[0072] 2211 first main valve pilot chamber

[0073] 2212 second main valve pilot chamber

[0074] 301 first accumulator

[0075] 302 second accumulator

[0076] 401 first check valve

[0077] 402 second check valve

[0078] 4021 control port

[0079] 500 upper limit pressure signal valve

[0080] 501 upper limit first valve position

[0081] 502 upper limit second valve position

[0082] 511 upper limit first valve port

[0083] 512 upper limit second valve port

[0084] 513 upper limit third valve port

[0085] 521 upper limit pilot chamber

[0086] 600 lower limit pressure signal valve

[0087] 601 lower limit first valve position

[0088] 602 lower limit second valve position

[0089] 611 lower limit first valve port

[0090] 612 lower limit second valve port

[0091] 613 lower limit third valve port

[0092] 621 lower limit pilot chamber

[0093] 700 Solenoid Valve

[0094] 701 Oil Inlet

[0095] 702 oil outlet

[0096] 800 Clutch Unloading Valve

[0097] 801 Unloading valve first position

[0098] 802 Unloading valve, second position

[0099] 811 Unloading valve first port

[0100] 812 Unloading valve second port

[0101] 821 Unloading valve pilot chamber

[0102] 901 shuttle valve

[0103] 911 First Safety Valve

[0104] 912 Second Safety Valve

[0105] 921 heat exchanger

[0106] 931 throttle orifice Detailed Implementation

[0107] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.

[0108] This application provides a hydraulic control system that can be used for pressure control of, for example, clutch cylinders in hybrid power transmissions and other loads.

[0109] See Figure 1A The hydraulic control system may include an oil pump 101, a main valve 200, an upper limit pressure signal valve 500, a lower limit pressure signal valve 600, and a solenoid valve 700.

[0110] More specifically, the oil pump 101 can be a one-way pump for one-way oil supply. A suction filter 1012 can also be installed between the oil pump 101 and the oil storage system 1011.

[0111] The main valve 200 can be a two-position three-way or two-position four-way pilot operated directional valve. The valve ports of the main valve 200 can include a main valve first port 211, a main valve second port 212, and a main valve third port 213. The main valve first port 211 is connected to the oil pump 101, the main valve second port 212 is connected to the clutch cylinder 103, and the main valve third port 213 is connected to the load 102 to be cooled and / or lubricated.

[0112] The main valve 200 can have a main valve first valve position 201 and a main valve second valve position 202. When the main valve first valve position 201 is in the working position (or the main valve 200 is switched to the main valve first valve position 201. Similarly, the following "a certain valve position is in the working position" means that the directional valve is switched to this valve position), the main valve first port 211 is connected to the main valve third port 213. When the main valve second valve position 202 is in the working position, the main valve first port 211 is connected to the main valve second port 212.

[0113] The main valve 200 can include a main valve pilot chamber 221 and a return spring. By controlling the oil filling state of the main valve pilot chamber 221, the working state of the main valve 200 can be controlled. More specifically, the main valve pilot chamber 221 can include a first main valve pilot chamber 2211 and a second main valve pilot chamber 2212.

[0114] The upper limit pressure signal valve 500 can be a two-position three-way or two-position four-way pilot operated directional valve. The valve ports of the upper limit pressure signal valve 500 can include an upper limit first port 511, an upper limit second port 512, and an upper limit third port 513. The upper limit first port 511 is connected to the main valve pilot chamber 221 (the first main valve pilot chamber 2211), the upper limit second port 512 is connected to the clutch cylinder 103, and the upper limit third port 513 is formed as a unloading port.

[0115] The upper limit pressure signal valve 500 can have an upper limit first valve position 501 and an upper limit second valve position 502. When the upper limit first valve position 501 is in the working position, the upper limit first port 511 is connected to the upper limit third port 513. When the upper limit second valve position 502 is in the working position, the upper limit first port 511 is connected to the upper limit second port 512.

[0116] The upper limit pressure signal valve 500 can include an upper limit pilot chamber 521 and a return spring. The upper limit pilot chamber 521 can be connected to the clutch cylinder 103, and thus the pressure of the clutch cylinder 103 can be used as a working position switching indication parameter of the upper limit pressure signal valve 500. For example, when the pressure of the clutch cylinder 103 is lower than a preset upper limit pressure (for example, 18 bar), the upper limit second valve position 502 is in the working position. When the pressure of the clutch cylinder 103 is higher than the upper limit pressure, the upper limit first valve position 501 is in the working position.

[0117] The lower limit pressure signal valve 600 can be a two-position three-way or two-position four-way pilot reversing valve. The valve ports of the lower limit pressure signal valve 600 can include a lower limit first valve port 611, a lower limit second valve port 612, and a lower limit third valve port 613. The lower limit first valve port 611 is connected to a control port 4021 (to be described later) of the second one-way valve 402, the lower limit second valve port 612 is connected to the one having a greater pressure between the oil pump 101 and the clutch cylinder 103 (for example, by a shuttle valve 901, to be described later), and the lower limit third valve port 613 is formed as a relief port.

[0118] The lower limit pressure signal valve 600 can have a lower limit first valve position 601 and a lower limit second valve position 602. When the lower limit first valve position 601 is in the working position, the lower limit first valve port 611 is connected to the lower limit third valve port 613. When the lower limit second valve position 602 is in the working position, the lower limit first valve port 611 is connected to the lower limit second valve port 612.

[0119] The lower limit pressure signal valve 600 can include a lower limit pilot chamber 621 and a return spring. The lower limit pilot chamber 621 can be connected to the clutch cylinder 103, and thus the pressure of the clutch cylinder 103 can be used as a working position switching indication parameter of the lower limit pressure signal valve 600. For example, when the pressure of the clutch cylinder 103 is lower than a preset lower limit pressure (for example, 12 bar), the lower limit second valve position 602 is in the working position. When the pressure of the clutch cylinder 103 is higher than the lower limit pressure, the lower limit first valve position 601 is in the working position.

[0120] The electromagnetic valve 700 can be a normally high pressure type pilot electromagnetic valve, which is configured to be able to electrically control the opening and closing state. The electromagnetic valve 700 can include an oil inlet port 701 and an oil outlet port 702. The oil inlet port 701 is connected to the one having a greater pressure between the oil pump 101 and the clutch cylinder 103, and the oil outlet port 702 is connected to the main valve pilot chamber 221 (the second main valve pilot chamber 2212). The on-off of the electromagnetic valve 700 can be coupled with the separation and engagement process of the clutch, and the specific setting form will be described later.

[0121] The hydraulic control system can further include a clutch relief valve 800, which can be a two-position reversing valve. The clutch relief valve 800 can include a relief valve first valve port 811 and a relief valve second valve port 812. The relief valve first valve port 811 is formed as a relief port, and the relief valve second valve port 812 is connected to the clutch cylinder 103.

[0122] The clutch relief valve 800 can have a relief valve first valve position 801 and a relief valve second valve position 802. When the relief valve first valve position 801 is in the working position, the relief valve first valve port 811 is disconnected from the relief valve second valve port 812. When the relief valve second valve position 802 is in the working position, the relief valve first valve port 811 is connected to the relief valve second valve port 812, and relief is achieved.

[0123] The clutch unloading valve 800 may include an unloading valve pilot chamber 821 and a return spring, and the oil outlet 702 may be connected to the pilot chamber.

[0124] A first check valve 401 and a first accumulator 301 can be connected in series between the second valve port 212 of the main valve and the clutch cylinder 103, so that the clutch cylinder 103 can still maintain oil pressure to a certain extent when the oil pump 101 does not supply oil to the clutch cylinder 103.

[0125] A second check valve 402 and a second accumulator 302 can be connected in series between the upper limit first valve port 511 and the main valve pilot chamber 221 (first main valve pilot chamber 2211). This allows the main valve pilot chamber 221 (first main valve pilot chamber 2211) to maintain oil pressure even after the oil pump 101 stops supplying oil to the main valve pilot chamber 221 (first main valve pilot chamber 2211) through the upper limit pressure signal valve 500, thus enabling the oil pump 101 to continue supplying oil to the load 102 that needs to be lubricated and / or cooled.

[0126] The second check valve 402 can be a hydraulically controlled check valve, in which the liquid flows in the forward direction from the upper limit first valve port 511 to the main valve pilot chamber 221 (first main valve pilot chamber 2211). The hydraulically controlled check valve includes a control port 4021. When oil is supplied to the control port 4021, the liquid in the second check valve 402 is allowed to flow backward.

[0127] The hydraulic control system of this application will now be described in detail based on the specific working conditions.

[0128] Operating Condition 1: Clutch Disengagement

[0129] See Figure 1A , Figure 1B When the solenoid valve 700 is de-energized and turned on, the oil pump 101 supplies oil to the unloading valve pilot chamber 821 and the main valve pilot chamber 221 (second main valve pilot chamber 2212).

[0130] The second valve position 802 of the unloading valve is in the working position, and the clutch cylinder 103 is unloaded.

[0131] The main valve is in the first valve position 201, which is the working position. The oil pump 101 supplies oil to the load 102 that needs to be lubricated and / or cooled.

[0132] Operating Condition 2: Clutch engagement and pressurization process (e.g., the oil pressure in clutch cylinder 103 is 0-12 bar).

[0133] See Figure 2A , Figure 2B The solenoid valve 700 is energized and disconnected.

[0134] When the first valve position 801 of the unloading valve is in the working position, the clutch cylinder 103 is not unloaded.

[0135] The main valve is in the working position at the second valve position 202. The oil pump 101 supplies oil to the clutch cylinder 103, and the first accumulator 301 is filled with oil.

[0136] Operating Condition 3: Clutch engagement - continued pressurization process (e.g., the oil pressure in clutch cylinder 103 is 12-18 bar).

[0137] See Figure 3A , Figure 3B The solenoid valve 700 is energized and disconnected.

[0138] When the first valve position 801 of the unloading valve is in the working position, the clutch cylinder 103 is not unloaded.

[0139] The main valve is in the working position at the second valve position 202. The oil pump 101 supplies oil to the clutch cylinder 103, and the first accumulator 301 is filled with oil.

[0140] Operating Condition 4: Clutch Engagement - Pressure Reaches Upper Limit (e.g., oil pressure in clutch cylinder 103 exceeds 18 bar)

[0141] See Figure 4A , Figure 4B The solenoid valve 700 is energized and disconnected.

[0142] When the first valve position 801 of the unloading valve is in the working position, the clutch cylinder 103 is not unloaded.

[0143] When the upper limit second valve position 502 is switched to the working position, the first accumulator 301 can supply oil to the main valve pilot chamber 221 (first main valve pilot chamber 2211).

[0144] When the main valve first position 201 switches to the working position, the oil pump 101 supplies oil to the load 102 to be lubricated and / or cooled. The oil pump 101 does not supply oil to the clutch cylinder 103, resulting in a drop in the oil pressure of the clutch cylinder 103.

[0145] Operating Condition 5: Clutch Engagement - Pressure Slowly Decreases (e.g., the oil pressure in clutch cylinder 103 drops from 18 bar to 12 bar)

[0146] See Figure 5A , Figure 5B The solenoid valve 700 is energized and disconnected.

[0147] When the first valve position 801 of the unloading valve is in the working position, the clutch cylinder 103 is not unloaded.

[0148] When the upper limit first valve position 501 is switched to the working position, the second accumulator 302 supplies oil to the main valve pilot chamber 221 (first main valve pilot chamber 2211).

[0149] The main valve first valve position 201 is maintained in the working position, the oil pump 101 supplies oil to the load 102 to be lubricated and / or cooled, and the oil pump 101 does not supply oil to the clutch cylinder 103, resulting in a drop in the oil pressure of the clutch cylinder 103.

[0150] Operating Condition 6: Clutch Engagement - Pressure Reaches Lower Limit (e.g., oil pressure in clutch cylinder 103 is less than 12 bar)

[0151] See Figure 6A , Figure 6B The solenoid valve 700 is energized and disconnected.

[0152] When the first valve position 801 of the unloading valve is in the working position, the clutch cylinder 103 is not unloaded.

[0153] When the lower limit second valve position 602 switches to the working position, the control port 4021 of the second check valve 402 is supplied with oil and backflow is allowed.

[0154] The upper limit first valve position 501 is the working position, and the second accumulator 302 is unloaded through the upper limit third valve port 513.

[0155] When the main valve's second valve position 202 switches to the working position, the oil pump 101 supplies oil to the clutch cylinder 103, the first accumulator 301 is filled with oil, and the pressure in the clutch cylinder 103 increases.

[0156] It should be understood that subsequent process conditions four, five, and six will occur cyclically. Additionally, if solenoid valve 700 is de-energized, the second valve position 802 of the unloading valve is in the working position, and clutch cylinder 103 is unloaded. Oil pump 101 supplies oil to the load 102 to be lubricated and / or cooled.

[0157] After the clutch in this application enters the engaged state, the pressure regulation is entirely completed by the hydraulic control system, and the clutch pressure fluctuates between the set upper and lower limits. During the clutch pressure holding phase, the oil pump 101 supplies oil to the load 102 that needs to be cooled and / or lubricated, thereby achieving energy saving.

[0158] Oil pump 101 does not participate in commutation and can be a simple unidirectional pump. There is no need for a reversible motor to drive oil pump 101, thus reducing limitations on the drive source. Pressure control and oil circuit switching during clutch engagement are entirely achieved by the hydraulic circuit, eliminating the need for sensors and electronic control units, resulting in cost advantages.

[0159] Additionally, see Figure 1A The hydraulic control system may include a shuttle valve 901. The input port of the shuttle valve 901 is connected to the oil pump 101 and the clutch cylinder 103, enabling the output of the higher pressure of the oil pump 101 and the clutch cylinder 103 through the shuttle valve 901. The output port of the shuttle valve 901 may be connected to the oil inlet 701 of the solenoid valve 700 and the lower limit third valve port 613.

[0160] It should be understood that the shuttle valve 901 can ensure that the control oil has sufficient pressure. For example:

[0161] When the clutch is just engaged, the pressure of the oil path where the clutch is located is 0, and it cannot be used as control oil. At this time, the shuttle valve 901 can output the outlet pressure of the oil pump 101 (the pressure of the cooling and lubricating oil path), and use it as the control power oil.

[0162] When the clutch is switched from the pressure maintaining state to the pressure charging state, the control oil needs to open the hydraulic control check valve (the second check valve 402). However, at this time, the high-pressure oil is in the main valve pilot chamber 221 (the first main valve pilot chamber 2211), and the oil pump 101 supplies the lubricating and cooling oil path, and the pressure is low. It will cause the hydraulic control check valve to be unable to open in time. At this time, the shuttle valve 901 can output the pressure oil of the oil path where the clutch is located, which has a higher pressure.

[0163] For the solenoid valve 700 (especially when the clutch is separated), sufficient oil supply pressure can obtain more stable control oil output.

[0164] In addition, the hydraulic control system can include a first safety valve 911 and a second safety valve 912. The first safety valve 911 can be arranged at the output port of the oil pump 101, and can be an overflow valve. When abnormal pressure build-up occurs, the first safety valve 911 can be automatically opened to release the pressure. The opening pressure of the first safety valve 911 can be slightly higher than the upper limit pressure, and the opening pressure of the first safety valve 911 can be set to, for example, 20 bar.

[0165] The second safety valve 912 can be arranged at the front end of the load 102 to be lubricated and / or cooled, and the second safety valve 912 can also be an overflow valve. In order to protect the components (such as plastic nozzles, heat exchangers 921, filters, and low-pressure components) on the cooling and lubricating oil path, when the cooling and lubricating oil path has abnormal pressure build-up, the second safety valve 912 will be opened to release the pressure, preventing the low-pressure components from being damaged. The opening pressure of the second safety valve 912 can be set to, for example, 1.5 bar.

[0166] In addition, the front end of the load 102 to be cooled and / or lubricated can also be provided with a heat exchanger 921.

[0167] In addition, the branch connected to the upper limit pilot chamber 521 and the branch connected to the lower limit pilot chamber 621 of the clutch oil cylinder 103 can be provided with a throttle hole 931 to improve the stability of the flow path.

[0168] In addition, the main valve, the upper limit pressure signal valve, and the lower limit pressure signal valve can be pilot-operated directional valves, and of course can also be solenoid-controlled valves.

[0169] In addition, the present application also provides the following technical solutions.

[0170] In one example, the hydraulic control system comprises an oil pump 101, a main valve 200, an upper limit pressure signal valve 500, and a lower limit pressure signal valve 600.

[0171] The main valve 200 is a two-position directional valve, comprising a main valve first valve position 201 and a main valve second valve position 202. The oil pump 101 can be connected to the load 102 to be cooled and / or lubricated via the main valve first valve position 201, and can be connected to the clutch oil cylinder 103 via the main valve second valve position 202.

[0172] The upper limit pressure signal valve 500 is a two-position directional valve, comprising an upper limit first valve position 501 and an upper limit second valve position 502. The hydraulic control system is configured such that when the pressure of the clutch oil cylinder 103 is greater than a preset upper limit pressure, the upper limit second valve position 502 is the working position, and the main valve first valve position 201 is switched to the working position, so that the oil pump 101 supplies oil to the load 102.

[0173] The lower limit pressure signal valve 600 is a two-position directional valve, comprising a lower limit first valve position 601 and a lower limit second valve position 602. The hydraulic control system is configured such that when the pressure of the clutch oil cylinder 103 is less than a preset lower limit pressure, the lower limit second valve position 602 is the working position, and the main valve second valve position 202 is switched to the working position, so that the oil pump 101 supplies oil to the clutch oil cylinder 103. The upper limit pressure is greater than the lower limit pressure.

[0174] In one example, the main valve 200 is a pilot directional valve, comprising a main valve first valve port 211, a main valve second valve port 212, a main valve third valve port 213, and a main valve pilot cavity 221.

[0175] The main valve first valve port 211 is connected to the oil pump 101, the main valve second valve port 212 is connected to the clutch oil cylinder 103, and the main valve third valve port 213 is connected to the load 102. The upper limit pressure signal valve 500 and the lower limit pressure signal valve 600 can change the working position of the main valve 200 by controlling the oil pressure of the main valve pilot cavity 221.

[0176] In one example, the oil pump 101 is a one-way pump.

[0177] In one example, the hydraulic control system comprises a solenoid valve 700, which is configured to be able to electrically control the opening and closing state. The solenoid valve 700 comprises an oil inlet port 701 and an oil outlet port 702. The oil inlet port 701 is connected to the one with greater pressure between the oil pump 101 and the clutch oil cylinder 103, and the oil outlet port 702 is connected to the main valve pilot cavity 221, thereby being able to change the working position of the main valve 200 through the solenoid valve 700.

[0178] In one example, the hydraulic control system comprises a clutch unloading valve 800, which is a two-position directional valve comprising a unloading valve first valve position 801 and a unloading valve second valve position 802. The clutch unloading valve 800 further comprises a unloading valve first valve port 811, a unloading valve second valve port 812 and a unloading valve pilot cavity 821. The unloading valve first valve port 811 is formed as a unloading port, the unloading valve second valve port 812 is connected to the clutch cylinder 103, and the outlet port 702 is connected to the unloading valve pilot cavity 821.

[0179] The hydraulic control system is configured such that when the unloading valve first valve position 801 is in the working position, the unloading valve first valve port 811 and the unloading valve second valve port 812 are disconnected; and when the unloading valve second valve position 802 is in the working position, the unloading valve first valve port 811 and the unloading valve second valve port 812 are connected to enable the clutch cylinder 103 to be unloaded.

[0180] In one example, the first one-way valve 401 and the first accumulator 301 are sequentially connected in series between the main valve second valve port 212 and the clutch cylinder 103, such that the hydraulic control system is configured such that when the outlet port 702 does not supply oil to the main valve pilot cavity 221 and the pressure of the clutch cylinder 103 is less than the lower limit pressure, the clutch cylinder 103 can gradually accumulate pressure.

[0181] In one example, the lower limit pressure signal valve 600 comprises a lower limit first valve port 611, a lower limit second valve port 612 and a lower limit pilot cavity 621. The lower limit second valve port 612 is connected to the one having greater pressure between the oil pump 101 and the clutch cylinder 103. The lower limit pilot cavity 621 is connected to the clutch cylinder 103, and when the pressure of the clutch cylinder 103 is greater than the lower limit pressure, the lower limit first valve position 601 is in the working position, and the lower limit first valve port 611 and the lower limit second valve port 612 are not in communication, such that the hydraulic control system is configured such that when the outlet port 702 does not supply oil to the main valve pilot cavity 221 and the pressure of the clutch cylinder 103 is greater than the lower limit pressure but does not exceed the upper limit pressure, the clutch cylinder 103 can gradually accumulate pressure.

[0182] In one example, the upper limit pressure signal valve 500 comprises an upper limit first valve port 511, an upper limit second valve port 512 and an upper limit pilot cavity 521. The upper limit first valve port 511 is connected to the main valve pilot cavity 221, the upper limit second valve port 512 is connected to the clutch cylinder 103, and the upper limit pilot cavity 521 is connected to the clutch cylinder 103. When the pressure of the clutch cylinder 103 is greater than the upper limit pressure, the upper limit second valve position 502 is in the working position, and the upper limit first valve port 511 and the upper limit second valve port 512 are in communication, thereby supplying oil to the main valve pilot cavity 221, such that the hydraulic control system is configured such that when the outlet port 702 does not supply oil to the main valve pilot cavity 221 and the pressure of the clutch cylinder 103 is greater than the upper limit pressure, the main valve first valve position 201 is switched to the working position.

[0183] In one example, the upper limit first valve port 511 is connected to the main valve pilot chamber 221 in sequence through the second check valve 402 and the second accumulator 302, so that the hydraulic control system is configured such that the second accumulator 302 maintains the main valve first valve position 201 at the working position.

[0184] In one example, the second check valve 402 is a hydraulic check valve, the hydraulic flow direction of which is from the upper limit first valve port 511 to the main valve pilot chamber 221, the hydraulic check valve comprises a control port 4021, the lower limit pressure signal valve 600 comprises a lower limit first valve port 611 and a lower limit second valve port 612, the lower limit first valve port 611 is connected to the control port 4021, and the control port 4021 is supplied with oil to allow the hydraulic check valve 402 to flow in reverse. The lower limit second valve port 612 is connected to the one with greater pressure between the oil pump 101 and the clutch oil cylinder 103. The upper limit pressure signal valve 500 comprises an upper limit third valve port 513, and the upper limit third valve port 513 is a unloading port, so that the hydraulic control system is configured such that when the pressure of the clutch oil cylinder 103 is less than the lower limit pressure, the lower limit second valve position 602 is at the working position, the lower limit first valve port 611 and the lower limit second valve port 612 are connected, the hydraulic check valve allows reverse flow, and the second accumulator 302 is unloaded through the upper limit third valve port 513.

[0185] In one example, the hydraulic control system comprises a shuttle valve 901, and the input port of the shuttle valve 901 is connected to the oil pump 101 and the clutch oil cylinder 103, so that the one with greater pressure between the oil pump 101 and the clutch oil cylinder 103 can be output through the shuttle valve 901.

[0186] The above is the preferred embodiment of the present application, and it should be pointed out that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A hydraulic control system, characterized in that, include: Oil pump; The main valve is a two-position directional valve, which includes a first valve position and a second valve position. The oil pump can be connected to the load to be cooled and / or lubricated via the first valve position, and the oil pump can be connected to the clutch cylinder via the second valve position. The upper limit pressure signal valve is a two-position directional valve, which includes an upper limit first valve position and an upper limit second valve position. The hydraulic control system is configured such that when the pressure of the clutch cylinder is greater than the preset upper limit pressure, the upper limit second valve position is in the working position, and the main valve first valve position is switched to the working position, so that the oil pump supplies oil to the load. The lower limit pressure signal valve is a two-position directional valve, which includes a lower limit first valve position and a lower limit second valve position. The hydraulic control system is configured such that when the pressure of the clutch cylinder is less than the preset lower limit pressure, the lower limit second valve position is in the working position, and the second valve position of the main valve is switched to the working position, so that the oil pump supplies oil to the clutch cylinder, and the upper limit pressure is greater than the lower limit pressure.

2. The hydraulic control system according to claim 1, characterized in that, The main valve is a pilot-operated directional valve, which includes: The first valve port of the main valve is connected to the oil pump; The second valve port of the main valve is connected to the clutch cylinder; The third valve port of the main valve is connected to the load. The main valve pilot chamber, the upper limit pressure signal valve and the lower limit pressure signal valve can change the working position of the main valve by controlling the oil pressure in the main valve pilot chamber, and the oil pump is a one-way pump.

3. The hydraulic control system according to claim 2, characterized in that, The hydraulic control system includes a solenoid valve configured to electrically change its opening and closing state, the solenoid valve comprising: The oil inlet is connected to the oil pump and the clutch cylinder, which has the higher pressure. The oil outlet is connected to the pilot chamber of the main valve, thereby enabling the solenoid valve to change the operating position of the main valve.

4. The hydraulic control system according to claim 3, characterized in that, The hydraulic control system includes a clutch unloading valve, which is a two-position directional valve, comprising a first unloading valve position and a second unloading valve position. The clutch unloading valve further includes: The first valve port of the unloading valve is formed as an unloading port; The second port of the unloading valve is connected to the clutch cylinder. The unloading valve pilot chamber, with the oil outlet connected to the unloading valve pilot chamber. The hydraulic control system is configured such that: when the first valve position of the unloading valve is in the working position, the first valve port and the second valve port of the unloading valve are disconnected; when the second valve position of the unloading valve is in the working position, the first valve port and the second valve port of the unloading valve are connected to enable the clutch cylinder to be unloaded.

5. The hydraulic control system according to claim 3, characterized in that, A first check valve and a first accumulator are connected in series between the second valve port of the main valve and the clutch cylinder. The hydraulic control system is configured such that when the oil outlet does not supply oil to the pilot chamber of the main valve and the pressure of the clutch cylinder is less than the lower limit pressure, the clutch cylinder can gradually accumulate pressure.

6. The hydraulic control system according to claim 3, characterized in that, The lower limit pressure signal valve includes: Lower limit first valve port; The lower limit second valve port is connected to the oil pump and the clutch cylinder with the greater pressure. The lower limit pilot chamber is connected to the clutch cylinder. When the pressure in the clutch cylinder is greater than the lower limit pressure, the lower limit first valve position is in the working position, and the lower limit first valve port and the lower limit second valve port are not in communication. The hydraulic control system is configured such that when the oil outlet does not supply oil to the pilot chamber of the main valve, and the pressure of the clutch cylinder is greater than the lower limit pressure but does not exceed the upper limit pressure, the clutch cylinder can gradually accumulate pressure.

7. The hydraulic control system according to claim 3, characterized in that, The upper limit pressure signal valve includes: The upper limit first valve port is connected to the pilot chamber of the main valve; The upper limit second valve port is connected to the clutch cylinder. The upper limit pilot chamber is connected to the clutch cylinder. When the pressure in the clutch cylinder is greater than the upper limit pressure, the upper limit second valve position is in the working position, and the upper limit first valve port is connected to the upper limit second valve port, thereby supplying oil to the main valve pilot chamber. The hydraulic control system is configured such that when the oil outlet does not supply oil to the pilot chamber of the main valve and the pressure of the clutch cylinder is greater than the upper limit pressure, the first valve position of the main valve switches to the working position.

8. The hydraulic control system according to claim 7, characterized in that, A second check valve and a second accumulator are sequentially connected in series between the upper limit first valve port and the main valve pilot chamber. The hydraulic control system is configured such that the second accumulator maintains the first valve position of the main valve as the operating position.

9. The hydraulic control system according to claim 8, characterized in that, The second check valve is a hydraulically controlled check valve, wherein the positive direction of liquid flow is from the upper limit first valve port to the main valve pilot chamber, and the hydraulically controlled check valve includes a control port. The lower limit pressure signal valve includes a lower limit first valve port and a lower limit second valve port. The lower limit first valve port is connected to the control port. When the control port is supplied with oil, it allows the liquid in the second check valve to flow back. The lower limit second valve port is connected to the oil pump and the clutch cylinder, which has the higher pressure. The upper limit pressure signal valve includes an upper limit third valve port, which is an unloading port. The hydraulic control system is configured such that when the pressure of the clutch cylinder is less than the lower limit pressure, the lower limit second valve position is in the working position, the lower limit first valve port and the lower limit second valve port are connected, the hydraulic control check valve allows backflow, and the second accumulator is unloaded via the upper limit third valve port.

10. The hydraulic control system according to any one of claims 3, 6, or 9, characterized in that, The hydraulic control system includes a shuttle valve, the inlet of which is connected to the oil pump and the clutch cylinder, enabling the output of the higher pressure of the oil pump and the clutch cylinder through the shuttle valve.

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