Control method of a hydraulic control system with an energy emergency module

Abstract

A control method for a hydraulic control system with an energy emergency module, including an energy supply unit, a steering unit, an energy emergency unit, a driving control unit, a parking control unit, and an axle braking unit; the energy supply unit provides normal energy for the entire hydraulic system; the steering unit outputs the oil volume and realizes vehicle steering; when the steering cylinder is impacted by the wheel hub and exceeds the limit pressure, the hydraulic oil is input into the accumulator to realize the recovery of high-pressure oil. When the energy supply unit is damaged, the energy emergency unit supplies energy to the system. When the pressure of the hydraulic system is insufficient, the energy emergency unit and the energy supply unit supply energy with double pumps to provide pressure oil for the system; the driving control unit controls vehicle service braking, emergency braking, and hydrodynamic retarder braking; the parking control unit controls braking lock and parking braking. The present invention can effectively avoid the problem that the vehicle cannot operate normally when a failure occurs in the braking unit or the steering unit of a heavy-duty vehicle.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle hydraulic control systems, and particularly relates to a control method for a hydraulic system with an energy emergency module. Background Art

[0002] When a heavy vehicle is operating in a mining area, due to its heavy load and complex road conditions, frequent steering and braking are required during driving. Therefore, a mining transport vehicle with a hydraulic control system is very important. During the process of a mining wide-body vehicle driving on a bumpy road, when steering, the uneven road surface will cause an instantaneous impact on the wheel hub, which will cause a change in the load of the steering axle, further impact the steering cylinder, and finally generate a pressure impact on the hydraulic control system, affecting the service performance of the steering cylinder. On the other hand, the energy generated by the hydraulic oil impact is not fully utilized, and at the same time, it will damage the stable working state of the components, affect the service life of the components of the hydraulic control system, and may even cause the hydraulic pipeline to burst and result in a safety accident in severe cases.

[0003] When a vehicle is loaded in a mining area road condition and faces an uneven road surface, it is easy to cause components such as hydraulic pipelines or brake valves to exceed their bearing pressures and leak, resulting in brake failure. The existing vehicle braking circuit is single. If there are faults such as pipeline oil leakage in the braking circuit, or the ABS valve group section fails due to the power failure of the vehicle control system, and the hydraulic oil cannot reach the brake and other faults; without emergency measures, accidents are likely to occur. Summary of the Invention

[0004] In order to overcome the above deficiencies, the present invention provides a control method for a hydraulic control system with an energy emergency module.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: a control method for a hydraulic control system with an energy emergency module, the hydraulic control system includes an energy supply unit, a steering unit, an energy emergency unit, a driving control unit, a parking control unit, and an axle braking unit, the steering unit includes a priority valve, a steering assembly, and a steering cylinder, and the energy emergency unit includes a flow cut-off valve, a motor, a variable pump, a first accumulator, and an emergency motor;

[0006] The control method of the hydraulic system is specifically as follows: the LS feedback set in the steering unit outputs the oil volume in real time according to the actual displacement demand of the metering motor. When the steering cylinder is impacted by the wheel hub and exceeds the limit pressure, the hydraulic oil enters the motor, drives the variable pump to rotate, and inputs the hydraulic oil into the accumulator, thereby completing a recovery of high-pressure oil; when the vehicle engine PTO is damaged or the hydraulic system pressure is insufficient, according to the actual demand, the energy emergency unit automatically supplements the pressure oil to the steering unit or the braking unit with low pressure through a three-position three-way directional control valve;

[0007] Among them, the axle braking unit includes rear axle left wheel braking modules, rear axle right wheel braking modules, middle axle left wheel braking modules, middle axle right wheel braking modules, front axle left wheel braking modules, and front axle right wheel braking modules with the same structure, as well as front axle left wheel disc brakes and front axle right wheel disc brakes. The rear axle left wheel braking module includes a full-disc wet brake, a backpressure valve group, an ABS valve group, and a two-position two-way valve. The A port of the full-disc wet brake is connected to the parking brake, and the B port is connected to the service brake. The backpressure valve group includes a shuttle valve, a throttle valve, and a relief valve. When the service brake and the parking brake are not activated, the pressure oil from the parking control unit enters the B port of the full-disc wet brake through the throttle valve and the shuttle valve, so that there is backpressure in the full-disc wet brake when it is not braking, and this pressure reduces the gap between the dynamic and static friction plates of the full-disc wet brake.

[0008] Further optimization: The oil pump inputs high-pressure oil into the priority valve and then into the steering gear assembly. The steering wheel of the steering gear assembly is connected to the metering motor, and the metering motor drives the follow-up rotary valve to move. The high-pressure oil enters the steering cylinder through the steering gear assembly to drive the steering axle, so as to realize the steering operation of the steering unit.

[0009] Further optimization: The LS feedback comes from the metering motor and the priority valve.

[0010] Further optimization: The recovered hydraulic oil includes the overload pressure of the steering unit and the hydraulic energy loss caused by extreme working conditions. When the pressure measured at the pressure measuring point shows that the pressure system is lower than the normal working range and the main oil pump cannot meet the oil supply of the entire system, the emergency motor starts to drive the variable pump to generate pressure oil, and the variable pump and the main oil pump achieve double-pump confluence to supplement energy for the system. When the vehicle power system fails and there is no pressure output from the system, the emergency motor starts, and the energy emergency unit supplies pressure oil to the steering unit or the braking unit as needed. In an emergency situation where both the steering unit and the braking unit are short of pressure oil, energy is preferentially supplied to the steering unit to ensure that the vehicle still has the steering ability.

[0011] Further optimization: The backpressure valve group is installed in front of the full-disc wet brake to improve the braking speed synchronization between the rear axle left wheel braking module, rear axle right wheel braking module, middle axle left wheel braking module, middle axle right wheel braking module and the front axle left wheel disc brake and front axle right wheel disc brake.

[0012] Further optimization: The ABS valve group includes a normally closed output solenoid valve and a normally open input solenoid valve. The ABS valve group closes or opens the normally open input solenoid valve or the normally closed output solenoid valve on the wheel according to the wheel locking state to prevent the wheels from being completely locked due to excessive braking force.

[0013] Further optimization: The two-position two-way valve always ensures normal braking of the vehicle when the vehicle-mounted system of the service brake fails.

[0014] For further optimization, the main circuit of the service brake circuit adopts a double-circuit cross layout to prevent sideslip and deviation, that is, the main oil supply circuits of the disc brakes on the right front wheel of the front axle, the braking modules on the left rear wheels of the middle and rear axles are one circuit, and the main oil supply circuits of the disc brakes on the left front wheel of the front axle, the braking modules on the right rear wheels of the middle and rear axles are one circuit; a relay valve is installed in front of each brake on the middle and rear axles to ensure that when a brake in the same circuit fails to brake, it does not affect the operation of other brakes, and the P port of each relay valve always has pressure oil to improve the braking response time of the middle and rear axles.

[0015] For further optimization, the axle braking unit further includes an emergency braking function and a braking locking function:

[0016] Emergency braking: When encountering an emergency condition, the vehicle control system automatically identifies it and directly drives the vehicle brakes to work through emergency braking, eliminating the reaction time of the driver, enabling the vehicle to brake quickly and accurately, and effectively shortening the braking distance;

[0017] Braking locking: When the vehicle speed is zero and there is no driver in the cab for more than the set time, the vehicle will automatically enter braking locking to ensure vehicle safety. At the same time, when other braking methods fail, braking locking can be used as a way of emergency braking.

[0018] For further optimization, the vehicle control system selects one of the parking safety mode or the driving priority mode:

[0019] In the parking safety mode, when the front pressure measurement point of the full-disc wet brake detects high-pressure oil in the hydraulic circuit and the pressure is within the normal range for releasing the parking brake, the vehicle can be started. When the vehicle is in the parking brake state, when the driver enters the cab, the parking brake light comes on, prompting the driver that the vehicle cannot be driven without releasing the parking brake;

[0020] In the driving priority mode, if the vehicle is in the parking brake state and the driver still starts the vehicle, when the system detects that the engine starts and the wheels have a tendency to rotate, the vehicle automatically releases the parking brake and the vehicle can drive. The beneficial effects of the present invention are:

[0021] 1. The energy recovery unit can use the recovered hydraulic energy for the steering unit or the braking unit; when the system pressure is too low or the vehicle engine power is damaged, the emergency motor of the energy recovery unit is started to drive the variable pump to work and provide pressure oil for the system, thus ensuring the normal operation of the vehicle;

[0022] 2. A back pressure valve group is installed in front of the full-disc wet brake to improve the lag of the braking response time of the middle and rear axles behind the front axle disc brake, significantly improving the braking speed of the rear and middle axles and greatly improving the synchronization with the front axle brake;

[0023] 3. The vehicle braking circuit adopts a cross - type layout. If there are problems such as leakage in one braking circuit, the other circuit can still work, ensuring the vehicle braking safety and preventing problems such as sideslip and deviation. A relay valve is installed in front of each brake of the middle and rear axles. Even if there are faults such as a brake being unable to brake in the same circuit, it does not affect the operation of other brakes;

[0024] 4. A relay valve is installed in front of each brake of the middle and rear axles. The P port of the relay valve always has pressure oil, which can improve the braking response time of the middle and rear axles;

[0025] 5. The vehicle is equipped with an emergency braking function. When encountering an emergency situation, such as vehicle yaw, sudden sharp turn, sudden encounter with pedestrians, obstacles, etc. that require emergency braking, the radar installed at the front end of the vehicle head detects the signal, the system identifies it, and issues a signal. This emergency braking carried out between vehicle control systems directly drives the vehicle brakes to work, eliminating the reaction time of the driver, enabling the vehicle to brake quickly and accurately, shortening the braking distance, and ensuring the safety of the vehicle and the driver; The vehicle is equipped with a braking lock function and a vehicle automatic lock function. When the vehicle speed is zero and there is no driver in the cab for more than the set time, the vehicle will automatically enter the braking lock, ensuring vehicle safety, especially when the vehicle is temporarily parked on an uphill or downhill section and is prone to rolling. Automatic braking lock is particularly important. At the same time, when other braking methods fail, the braking lock can also be used as a way of emergency braking; The parking brake is introduced into the vehicle control system, and the parking safety mode and driving priority mode can be set for the driver to choose. Description of the Drawings

[0026] Figure 1 is the hydraulic schematic diagram of the present invention;

[0027] Figure 2 is the hydraulic schematic diagram of the energy supply unit;

[0028] Figure 3 is the hydraulic schematic diagram of the steering unit;

[0029] Figure 4 is the hydraulic schematic diagram of the energy emergency unit;

[0030] Figure 5 is the hydraulic schematic diagram of the driving control unit;

[0031] Figure 6 is the hydraulic schematic diagram of the parking control unit;

[0032] Figure 7 is the hydraulic schematic diagram of the axle braking unit;

[0033] Figure 8It is the structural schematic diagram of a full-disc wet brake;

[0034] In the figure: 1. Energy supply unit, 101. Oil tank, 102. Engine PTO, 103. Main oil pump, 104. First check valve, 105. First pressure measurement point, 106. First relief valve, 2. Steering unit, 201. Second check valve; 202. Priority valve; 203. Steering gear assembly; 204. Follow-up rotary valve; 205. Metering motor; 206. Third check valve; 207. Steering cylinder, 3. Energy emergency unit, 301. Fourth check valve, 302. Fifth check valve, 303. Motor, 304. Flow cut-off valve, 305. Sixth check valve, 306. Variable pump, 307. Emergency motor, 308. Second relief valve, 309. First accumulator; 310. Constant flow valve; 311. Three-position three-way directional control valve; 312. Seventh check valve; 313. Eighth check valve; 314. First two-way buffer valve; 315. Two-position four-way solenoid valve, 4. Driving control unit, 401. Second accumulator, 402. Ninth check valve; 403. Second pressure measurement point; 404. Third relief valve; 405. Tenth check valve; 406. Two-position two-way solenoid valve; 407. First shuttle valve; 408. Second shuttle valve; 409. Brake pedal valve; 410. Eleventh check valve; 411. Pressure reducing valve; 412. First throttle valve; 413. Hydrodynamic retarder solenoid valve; 414. Hydrodynamic retarder cylinder, 5. Parking control unit, 501. Two-position three-way solenoid valve, 502. Twelfth check valve, 503. Thirteenth check valve, 504. Hand pump, 505. Fourteenth check valve, 506. Third accumulator, 507. Fourteenth check valve, 508. Parking brake valve, 509. Parking switch, 510. Fourth relief valve, 6. Axle brake unit, 601. First relay valve, 602. Third shuttle valve, 603. Second relay valve, 604. ABS valve group, 605. Two-position two-way valve, 606. Back pressure valve group, 607. Fourth shuttle valve, 608. Second throttle valve, 609. Full-disc wet brake, 610. Rear axle left wheel brake module, 611. Third pressure measurement point, 612. Fifth relief valve; 613. Normally open input solenoid valve, 614. Normally closed output solenoid valve, 615. Rear axle right wheel brake module, 616. Third relay valve, 617. Fifth shuttle valve, 618. Fourth relay valve, 619. Middle axle right wheel brake module, 620. Front axle right wheel disc brake, 621. Front axle left wheel disc brake, 622. Middle axle left wheel brake module, 623. Parking brake spring, 624. Parking brake piston, 625. Static friction plate, 626. Dynamic friction plate, 627. Driving brake piston, 628. Driving brake return spring. Specific implementation mode

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention.

[0036] A control method for a hydraulic control system with an energy emergency module, where the hydraulic system includes an energy supply unit 1, a steering unit 2, an energy emergency unit 3, a driving control unit 4, a parking control unit 5, and an axle braking unit 6.

[0037] The energy supply unit 1 includes a fuel tank 101, an engine PTO 102, a main oil pump 103, a first one-way valve 104, a first pressure measurement point 105, and a first overflow valve 106.

[0038] The engine PTO 102 drives the main oil pump 103 to supply pressure oil to the entire hydraulic system. The first overflow valve 106 prevents the main oil pump 103 from being damaged due to excessive outlet pressure, and the first one-way valve 104 prevents the system pressure oil from flowing back and affecting the operation of the main oil pump 103.

[0039] The steering unit 2 includes a second one-way valve 201, a priority valve 202, a steering assembly 203, a follow-up rotary valve 204, a metering motor 205, a third one-way valve 206, and a steering cylinder 207.

[0040] The second one-way valve 201 separates the steering unit 2 from other units, enabling the pressure oil from the energy emergency unit 3 to directly enter the steering unit 2 entirely. There is an LS feedback between the priority valve 202 and the metering motor 205 in the steering assembly 203. The priority valve 202 can output oil according to the steering wheel rotation speed of the connected metering motor 205 for the actual displacement demand of the metering motor 205, so that the steering cylinder 207 can quickly complete telescoping to achieve steering. When the steering cylinder 207 is under extreme impact, to avoid scratching of the piston rod by hard pulling, in any one cavity during left and right steering, hard pulling of the other steering cylinder will cause air suction. At this moment, the oil can be replenished into the suction cavity through the connection of the third one-way valve 206 to the fuel tank 101.

[0041] The energy emergency unit 3 includes a fourth one-way valve 301, a fifth one-way valve 302, a motor 303, a flow direction cut-off valve 304, a sixth one-way valve 305, a variable pump 306, an emergency motor 307, a second overflow valve 308, a first accumulator 309, a first constant flow valve 310, a three-position three-way directional control valve 311, a seventh one-way valve 312, an eighth one-way valve 313, a first two-way buffer valve 314, and a two-position four-way solenoid valve 315.

[0042] Pressure measuring points R and L are respectively set at the inlet and return oil ports of the two steering cylinders 207, and pressure detection switches are also set. When the pressure at the steering cylinder 207 detected by the pressure measuring point R or the pressure measuring point L is greater than the system set pressure, the two-position four-way solenoid valve 315 in the energy emergency unit 3 opens to the left position, guiding the impact into the first accumulator 309 to absorb the hydraulic oil, and the first energy recovery is completed. When the vehicle encounters a sharp turn and the steering wheel is turned to the limit or the road surface is bumpy, the steering cylinder 207 will be impacted by the wheel hub at this time. If the impact generated at this time exceeds the pressure value set by the first two-way buffer valve 314, the oil will enter the energy emergency unit 3 from the first two-way buffer valve 314 to relieve the pressure impact and complete the recovery work of hydraulic energy.

[0043] The pressure oil recovered from the steering unit 2 is stored in the first accumulator 309. The sixth one-way valve 305 prevents the pressure oil from flowing back and affecting the variable pump 306; the second overflow valve 308 protects the energy emergency unit 3 to prevent the pressure of the first accumulator 309 from overloading; the first constant flow valve 310 prevents the high-pressure oil of the accumulator from directly flowing through to the steering cylinder 207; when the P port and the A port of the three-position three-way directional control valve 311 are connected, the energy emergency unit 3 supplies energy to the steering unit 2, and when the P port and the B port of the three-position three-way directional control valve 311 are connected, the energy emergency unit 3 supplies energy to the braking part; the energy emergency unit 3 can supplement energy to the hydraulic system either manually or automatically by the system. Its control method is to compare the pressure measuring points R and L of the steering unit and the second pressure measuring point 403 in the vehicle control unit 4, and the three-position three-way directional control valve 311 in the energy emergency unit 3 automatically supplements the pressure oil to the unit with lower pressure.

[0044] A first pressure measuring point 105 is set in the energy supply unit 1. If it is measured that the system pressure is lower than the normal working range and the oil pump 103 cannot meet the oil supply of the entire system, the emergency motor 307 starts to drive the variable pump 306 to generate pressure oil, and realizes the combined flow of the two pumps with the main oil pump 103 to supplement energy to the system. If a fault occurs in the vehicle power system and there is no pressure output from the system, the emergency motor 307 starts, and the energy emergency unit 3 supplies pressure oil to the steering unit 2 or the entire braking part as needed; in the emergency condition where both the steering and braking have insufficient pressure oil, it preferentially supplies energy to the steering unit 2 to ensure that the vehicle still has the steering ability. The eighth one-way valve 313 prevents the pressure oil of the braking part from entering the energy emergency unit 3, and the seventh one-way valve 312 prevents the pressure oil of the steering unit 2 from entering the energy emergency unit 3; when there is no energy emergency in the hydraulic system, the flow direction cut-off valve 304 closes. The fourth one-way valve 301 and the fifth one-way valve 302 separate the pressure oil of the braking part from the energy supply unit 1 and the steering unit 2.

[0045] The driving control unit 4 includes a second accumulator 401, a ninth one-way valve 402, a second pressure measurement point 403, a third overflow valve 404, a tenth one-way valve 405, a two-position two-way solenoid valve 406, a first shuttle valve 407, a second shuttle valve 408, a brake pedal valve 409, an eleventh one-way valve 410, a pressure reducing valve 411, a first throttle valve 412, a hydrodynamic retarder solenoid valve 413, and a hydrodynamic retarder cylinder 414.

[0046] The second accumulator 401 provides hydraulic oil for the braking part. The ninth one-way valve 402 prevents the pressure oil in the braking circuit from flowing back, and the third overflow valve 404 prevents the second accumulator 401 from overloading, playing a protective role.

[0047] Working state during driving braking: The main circuit of the driving braking circuit adopts a cross layout, that is, the main oil supply circuits of the front right wheel disc brake 620, the middle left wheel braking module 622, and the rear left wheel braking module 610 of the front axle are one circuit, and the main oil supply circuits of the front left wheel disc brake 621, the middle right wheel braking module 619, and the rear right wheel braking module 615 of the front axle are one circuit; if there are problems such as pressure oil leakage in one of the circuits, the other circuit can still continue to work. This cross layout enables the brakes on both sides of the vehicle to work even if one circuit has problems, and there is still braking force, effectively preventing problems such as vehicle deviation and side slip. In the main oil circuit of the braking circuit, the hydraulic oil flows through the P ports of the first relay valve 601, the second relay valve 603, the third relay valve 616, and the fourth relay valve 618 from the second accumulator 401.

[0048] When the brake pedal valve 409 is depressed, one control oil circuit goes from the P1 port to the A1 port of the brake pedal valve 409, reaches the front left wheel disc brake 621 through the first shuttle valve 407, and the fifth shuttle valve 617, and enters the control oil ports L of the third relay valve 616 and the fourth relay valve 618, making the P ports and A ports of the third relay valve 616 and the fourth relay valve 618 communicate with each other, and further enters the B port of the full-disc wet brake in the middle right wheel braking module 619 and the rear right wheel braking module 615 to implement driving braking; the other control oil circuit goes from the P2 port to the A2 port of the brake pedal valve 409, reaches the front right wheel disc brake 620 through the second shuttle valve 408, and the third shuttle valve 602, and enters the control oil ports L of the second relay valve 603 and the first relay valve 601, making the P ports and A ports of the second relay valve 603 and the first relay valve 601 communicate with each other, and further enters the B port of the full-disc wet brake 609 in the middle left wheel braking module 622 and the rear left wheel braking module 610 to implement driving braking.

[0049] On multi-up-and-downhill sections, drivers need to frequently step on the brake pedal valve 409. When stepping on the brake pedal valve 409 for a long time, it is very easy to cause driver fatigue and weak feet. The vehicle-mounted system detects the force, angle, time, etc. of the driver stepping on the brake pedal valve 409. Following the situation of the driver stepping on the brake pedal 409, the system automatically applies electromagnetic control to assist in controlling the opening of the brake pedal valve 409, reducing driver fatigue and ensuring vehicle safety.

[0050] Emergency braking: When encountering an emergency condition, such as vehicle yaw, sudden sharp turn and suddenly encountering pedestrians, obstacles, etc. that require emergency braking, the radar installed at the front end of the vehicle head detects a signal, the system identifies it and sends a signal. The two-position two-way solenoid valve 406 is energized, and the hydraulic oil enters the first shuttle valve 407 and the second shuttle valve 408 through the two-position two-way solenoid valve 406. One way reaches the front axle left wheel disc brake 621 through the first shuttle valve 407, and the fifth shuttle valve 617, and enters the control oil ports L of the third relay valve 616 and the fourth relay valve 618, so that the P ports and A ports of the third relay valve 616 and the fourth relay valve 618 are communicated with each other, and further enters the B ports of the full-disc wet brakes in the middle bridge right wheel brake module 619 and the rear axle right wheel brake module 615 to implement service braking; the other way reaches the front axle right wheel disc brake 620 through the third shuttle valve 408, and the third shuttle valve 602, and enters the control oil ports L of the second relay valve 603 and the first relay valve 601, so that the P ports and A ports of the second relay valve 603 and the first relay valve 601 are communicated with each other, and further enters the B ports of the full-disc wet brakes 609 in the middle bridge left wheel brake module 622 and the rear left wheel brake module 610 to implement service braking. The tenth check valve 405 connects the emergency braking circuit and separates the emergency braking circuit from other brakes. If there is a pressure oil leakage in other braking circuits, it will not affect the emergency braking circuit.

[0051] This kind of emergency braking carried out between vehicle-mounted systems directly drives the vehicle brakes to work, eliminating the reaction time of the driver, enabling the vehicle to brake quickly and accurately, shortening the braking distance, and ensuring the safety of the vehicle and the driver.

[0052] Hydraulic retarder braking: It is achieved through the retarder in the gearbox. The high-speed rotation of the rotor blades stirs the hydraulic oil in the working chamber, generating a resistance torque. The hydraulic oil circulates and impacts the stator blades in the working chamber, converting mechanical energy into the heat energy of the working fluid and taking away the heat through the heat dissipation mechanism. The role of the hydraulic retarder valve group is to control the hydraulic retarder solenoid valve 413. When the hydraulic retarder solenoid valve 413 is energized, the hydraulic oil is introduced into the hydraulic retarder cylinder 414, and the hydraulic retarder cylinder 414 is used to control the opening and closing of the hydraulic retarder plunger valve on the gearbox, thereby controlling the oil inlet and outlet of the hydraulic retarder in the gearbox. The first throttle valve 412 prevents high-pressure oil from directly accessing the hydraulic retarder cylinder 414.

[0053] When going down a long slope, in order to prevent the vehicle speed from being too fast, braking is required to reduce the speed. However, due to the long braking time, it often leads to a large amount of heat generation in the brake disc, too high temperature, a sharp reduction in the friction coefficient, affecting the driving braking effect, and even causing the brake disc to carbonize and fail. To prevent this situation from occurring, a hydraulic retarder brake valve group is added to the hydraulic braking system.

[0054] Two braking methods, namely brake disc braking and hydraulic retarder braking, are alternately used in combination to reduce the vehicle speed. If the temperature of the brake disc or the oil is too high, it will switch to the other braking method. The vehicle control system can alternately and automatically control the electric control braking system and the hydraulic retarder braking system to achieve a suitable vehicle speed for going downhill until the downhill ends.

[0055] The parking control unit 5 includes a two-position three-way solenoid valve 501, a twelfth one-way valve 502, a thirteenth one-way valve 503, a manual pump 504, a fourteenth one-way valve 505, a third accumulator 506, a fourteenth one-way valve 507, a parking brake valve 508, and a parking switch 509.

[0056] Brake locking: When starting brake locking, the two-position three-way solenoid valve 501 is energized, and the pressure oil reaches the third shuttle valve 602 and the fifth shuttle valve 617 through the two-position three-way solenoid valve 501. One way enters the control oil port L of the second relay valve 603 and the first relay valve 601 through the third shuttle valve 602, making the P port and the A port of the second relay valve 603 and the first relay valve 601 communicate with each other, and the pressure oil further enters the B port of the full-disc wet brake 609 in the middle bridge left wheel brake module 622 and the rear bridge left wheel brake module 610 to implement brake locking; the other way enters the control oil port L of the third relay valve 616 and the fourth relay valve 618 through the fifth shuttle valve 617, making the P port and the A port of the third relay valve 616 and the fourth relay valve 618 communicate with each other, and the pressure oil further enters the B port of the full-disc wet brake in the middle bridge right wheel brake module 619 and the rear bridge right wheel brake module 615 to implement brake locking. The twelfth one-way valve 502 separates the brake locking circuit from other braking circuits, and the pressure oil is not affected by other pipelines.

[0057] During brake locking, at this time, the ABS no longer prevents the wheels from locking, the normally open valve group opens, and the normally closed valve group closes, only serving to connect the oil circuit.

[0058] When the vehicle speed is zero and there is no driver in the cab of the vehicle, the vehicle control system can set the locking time. For example, if the detection time is set to 5 minutes, and there is no movement change trend of the vehicle and no driver in the cab within five minutes, then the vehicle will automatically enter brake locking to ensure vehicle safety. Especially when the vehicle is temporarily parked on an uphill or downhill section and is prone to slipping, automatic brake locking is particularly important.

[0059] Parking brake: Since pressure oil is required to overcome the spring force to release the parking brake, pressure oil always flows through the parking brake circuit in the state of released parking brake. The thirteenth one-way valve 503 ensures that the pressure oil entering the third accumulator 506 from the oil pump 103 is not affected by other circuits. The third accumulator 506 provides buffer pressure oil for the parking brake. When the parking brake valve 508 is pressed, the pressure oil enters port A of the full-disc wet brake in the rear axle left-wheel brake module 610, rear axle right-wheel brake module 615, middle axle left-wheel brake module 622, and middle axle right-wheel brake module 619. The pressure oil overcomes the spring force to release the parking brake; when the oil supply pressure of the third accumulator 506 is low and the parking brake switch is closed, to prevent the automatic application of the parking function of the full-disc wet brake, a fourteenth one-way valve 507 is set in the parking brake oil circuit to prevent the pressure oil in the full-disc wet brake from flowing back to the oil supply circuit and keep the parking brake in the released position.

[0060] If the pressure of the third accumulator 506 is too low due to the vehicle not being used for a long time, or in the case of oil leakage in the parking brake circuit, etc., the manual pump 504 can be used to provide pressure oil for the circuit to release the parking brake. The fourteenth one-way valve 505 prevents the system pressure oil from entering the manual pump 504. The fourth relief valve 510 prevents excessive pressure of the manual pump 504 from causing damage.

[0061] When port A and port T of the parking brake valve 508 are connected, the hydraulic oil in each brake returns to the fuel tank and the parking brake is activated. The system is equipped with a parking switch 509. When the vehicle's parking brake is activated, this switch is activated and the vehicle cannot move, preventing the driver from driving without releasing the parking brake and causing damage to the brakes.

[0062] The vehicle-mounted system can set the parking safety mode. Pressure measurement points are installed in front of each brake, such as the third pressure measurement point 611. When the pressure measurement point detects high-pressure oil in the hydraulic circuit and the pressure is within the normal range for releasing the parking brake, the vehicle can start the engine. When the vehicle is in the parking brake state, when the driver enters the cab, the parking brake light comes on to prompt the driver, preventing damage to the parking brake and even greater hazards caused by the driver's misoperation and driving without releasing the parking brake.

[0063] The vehicle-mounted parking system can also be set to the vehicle driving priority mode. If the operator applies the parking brake and the driver still starts the engine, when the system detects that the engine starts and the wheels have a tendency to rotate, the parking brake valve 508 is automatically energized to connect the circuit, and the pressure oil enters the parking brake to release the parking brake, and the vehicle can then drive.

[0064] The axle braking unit 6 includes a first relay valve 601, a third shuttle valve 602, a second relay valve 603, a third relay valve 616, a fifth shuttle valve 617, a fourth relay valve 618, a front axle right wheel disc brake 620, a front axle left wheel disc brake 621, and a rear axle left wheel braking module 610, a rear axle right wheel braking module 615, a middle axle left wheel braking module 622, and a middle axle right wheel braking module 619 with the same structure; and the rear axle left wheel braking module 610 includes a full disc wet brake 609, a back pressure valve group 606, an ABS valve group 604, and a two-way two-position valve 605. The ABS valve group 604 is composed of a normally open input solenoid valve 613 and a normally closed output solenoid valve 614. The back pressure valve group 606 is composed of a fourth shuttle valve 607, a second throttle valve 608, and a fifth overflow valve 612. The full disc wet brake 609 is composed of a parking brake spring 623, a parking brake piston 624, static friction plates 625, dynamic friction plates 626, a service brake piston 627, and a service brake return spring 628.

[0065] Port A of the full disc wet brake 609 is connected to the parking brake, and port B is connected to the service brake. The back pressure valve group 606 includes a fourth shuttle valve 607, a second throttle valve 608, and a fifth overflow valve 612. When the service brake and the parking brake are not activated, the pressure oil from the parking control unit 5 enters port B of the full disc wet brake 609 through the second throttle valve 608 and the fourth shuttle valve 607, so that there is back pressure in the full disc wet brake 609 when it is not braking. This pressure reduces the gap between the static and dynamic friction plates of the full disc wet brake 609. If the pressure is too high, the hydraulic oil is relieved through the fifth overflow valve 612. The ABS valve group 604 includes a normally closed output solenoid valve 614 and a normally open input solenoid valve 613. The ABS valve group 604 can quickly judge the locked state of the wheel according to the speed signal transmitted by the speed sensor installed on the wheel. For example, according to the wheel locked state, the ABS valve group 604 closes the normally open input solenoid valve 614 on the wheel that starts to lock, so that the braking force remains unchanged. If the wheel continues to lock, the normally closed output solenoid valve 613 is opened, and the braking pressure oil on this wheel directly leads to the fuel tank, and the braking force quickly drops, preventing the wheel from being completely locked due to excessive braking force. When keeping the braking state always at the best slip ratio, the braking effect reaches the best and driving is the safest.

[0066] The two-way two-position valve 605 is normally closed when energized. If the vehicle wades through water and the vehicle control system is powered off and cannot be used, that is, the ABS valve group 604 is all closed and the hydraulic oil cannot enter the brake, the two-way two-position valve 605 loses power and opens, and the circuit is connected, always ensuring that the pressure oil can be introduced into each brake during service braking, greatly ensuring the safety of service braking. The ABS valve group 604 and the two-way two-position valve 605 are also installed in front of the front axle right wheel disc brake 620 and the front axle left wheel disc brake 621, and their working principles are the same as those of the ABS valve group 604 and the two-way two-position valve 605.

[0067] Working principle of the full-disc wet brake 609:

[0068] When the parking brake is released, the pressure oil enters chamber A, compressing the parking brake spring 623. The parking brake piston 624 moves to the leftmost end. At this time, the gap between the static friction plate 625 and the dynamic friction plate 626 is the largest. When the parking brake is applied, the pressure oil returns from chamber A to the fuel tank. The parking brake spring 623 presses the dynamic friction plate 626 against the static friction plate 625, thereby generating braking force to apply the parking brake.

[0069] When the service brake is applied, the pressure oil enters through port B, overcoming the force of the service brake return spring 628, and pushing the service brake piston 627 to move leftward, pressing the dynamic friction plate 626 against the static friction plate 625, thereby generating braking force to apply the service brake.

[0070] Working principle of the relay valve: Taking the first relay valve 601 as an example, when there is no hydraulic oil at the control port L of the first relay valve 601, due to the action of the return spring, the oil outlet A of the first relay valve 601 is communicated with the oil return port T and not communicated with the oil inlet P. When hydraulic oil enters the control port L of the first relay valve 601, the hydraulic oil pushes the spool to move rightward. The spool gradually cuts off the communication between the oil outlet A and the oil return port T and connects the oil inlet P and the oil outlet A. At the same time, the hydraulic oil at the oil outlet A flows into the bottom of the spool through the damping hole on the spool and generates a feedback force that prevents the spool from continuing to move rightward. As the spool moves rightward, the output pressure increases and the feedback force continuously increases until the resultant force of the steady-state hydraulic force, the feedback force, and the return spring is greater than the thrust generated by the control pressure at the left end of the spool. Then the spool moves in the reverse direction, closing the throttle port between the oil inlet P and the oil outlet A. At this time, the spool is balanced under the combined action of the hydraulic thrust, the spring force, and the hydraulic feedback force, and the oil pressure at the oil outlet A of the relay valve remains stable. When the hydraulic oil at the control port L of the first relay valve 601 is disconnected, the spool resets under the action of the return spring, and the oil outlet A is communicated with the oil return port T and not communicated with the oil inlet P.

[0071] The above shows and describes the main features, usage methods, basic principles, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have various changes and improvements according to actual situations. These changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A control method for a hydraulic control system with an energy emergency module, the hydraulic control system comprising an energy supply unit, a steering unit, an energy emergency unit, a driving control unit, a parking control unit, and an axle braking unit, characterized in that, The steering unit includes a priority valve, a steering assembly, and a steering cylinder. The energy emergency unit includes a flow cut-off valve, a motor, a variable pump, a first accumulator, and an emergency motor; The control method of the hydraulic system is specifically as follows: The LS feedback set in the steering unit outputs the oil volume in real time according to the actual displacement demand of the metering motor. When the steering cylinder is impacted by the wheel hub and exceeds the limit pressure, the hydraulic oil enters the motor, drives the variable pump to rotate, and inputs the hydraulic oil into the accumulator, thus completing a recovery of high-pressure oil. When the vehicle engine PTO is damaged or the hydraulic system pressure is insufficient, according to the actual demand, the energy emergency unit automatically supplements the pressure oil to the steering unit or the braking unit with low pressure through a three-position three-way directional control valve; Among them, the axle braking unit includes rear axle left wheel braking modules, rear axle right wheel braking modules, middle axle left wheel braking modules, middle axle right wheel braking modules, front axle left wheel braking modules, and front axle right wheel braking modules with the same structure, as well as front axle left wheel disc brakes and front axle right wheel disc brakes. The rear axle left wheel braking module includes a full-disc wet brake, a backpressure valve group, an ABS valve group, and a two-position two-way valve. The A port of the full-disc wet brake is connected to the parking brake, and the B port is connected to the service brake. The backpressure valve group includes a shuttle valve, a throttle valve, and a relief valve. When the service brake and the parking brake are not activated, the pressure oil from the parking control unit enters the B port of the full-disc wet brake through the throttle valve and the shuttle valve, so that there is backpressure in the full-disc wet brake when it is not braking, and this pressure reduces the gap between the dynamic and static friction plates of the full-disc wet brake.

2. The control method of a hydraulic control system with an energy emergency module as claimed in claim 1, wherein, The oil pump inputs high-pressure oil into the priority valve and enters the steering gear assembly. The steering wheel of the steering gear assembly is connected to the metering motor, and the metering motor drives the follow-up rotary valve to move. The high-pressure oil enters the steering cylinder through the steering gear assembly to drive the steering axle, so as to realize the steering operation of the steering unit.

3. The control method of a hydraulic control system with an energy emergency module as described in claim 1, characterized in that, The LS feedback comes from the metering motor and the priority valve.

4. The control method of a hydraulic control system with an energy emergency module as described in claim 1, characterized in that, The recovered hydraulic oil includes the overload pressure of the steering unit and the hydraulic energy loss caused by extreme working conditions; If the pressure system measured at the pressure measurement point is lower than the normal working range and the main oil pump cannot meet the oil supply of the entire system, the emergency motor starts, drives the variable pump to generate pressure oil, and drives the variable pump and the main oil pump to achieve double-pump confluence to supplement energy for the system; If a fault occurs in the vehicle power system and there is no pressure output in the system, the emergency motor starts, and the energy emergency unit supplies pressure oil to the steering unit or the braking unit as needed; In an emergency situation where both the steering unit and the braking unit are short of pressure oil, energy is supplied to the steering unit first to ensure that the vehicle still has the steering ability.

5. The control method of a hydraulic control system with an energy emergency module as claimed in claim 1, wherein, The backpressure valve group is installed in front of the full-disc wet brake to improve the braking speed synchronization of the rear axle left wheel braking module, rear axle right wheel braking module, middle axle left wheel braking module, middle axle right wheel braking module, front axle left wheel disc brake, and front axle right wheel disc brake.

6. The control method of a hydraulic control system with an energy emergency module as claimed in claim 1, characterized in that, The ABS valve group includes a normally closed output solenoid valve and a normally open input solenoid valve. The ABS valve group closes or opens the normally open input solenoid valve or the normally closed output solenoid valve on the wheel according to the wheel lock-up state to prevent the wheels from being completely locked due to excessive braking force.

7. The control method of a hydraulic control system with an energy emergency module as described in claim 1, characterized in that, When a fault occurs in the vehicle-mounted system of the service brake, the two-way two-position valve always ensures normal braking of the vehicle.

8. The control method of a hydraulic control system with an energy emergency module as claimed in claim 1, characterized in that, The main circuit of the service brake circuit adopts a double-circuit cross arrangement to prevent sideslip and deviation. That is, the main oil supply circuits of the right disc brake of the front axle, the left wheel brake module of the middle axle, and the left wheel brake module of the rear axle are one circuit, and the main oil supply circuits of the left disc brake of the front axle, the right wheel brake module of the middle axle, and the right wheel brake module of the rear axle are one circuit; A relay valve is installed in front of each brake of the middle and rear axles to ensure that when a brake in the same circuit fails to brake, it does not affect the operation of other brakes, and the P port of each relay valve always has pressure oil to improve the braking response time of the middle and rear axles.

9. The control method of a hydraulic control system with an energy emergency module as claimed in claim 1, wherein, The axle brake unit also includes an emergency braking function and a braking lock function: Emergency braking: When an emergency condition occurs, the vehicle-mounted system automatically recognizes it and directly drives the vehicle brakes to work in emergency braking, eliminating the reaction time of the driver, enabling the vehicle to brake quickly and accurately, and effectively shortening the braking distance; Braking lock: When the vehicle speed is zero and there is no driver in the cab of the vehicle for more than the set time, the vehicle will automatically enter the braking lock to ensure vehicle safety. At the same time, when other braking methods fail, the braking lock can be used as a way of emergency braking.

10. The control method of a hydraulic control system with an energy emergency module as described in claim 1, characterized in that, The vehicle-mounted system selects one of the parking safety mode or the driving priority mode: In the parking safety mode, the vehicle can be started only when the front pressure measuring point of the full-disc wet brake detects high-pressure oil in the hydraulic circuit and the pressure is within the normal range for releasing the parking brake. When the vehicle is in the parking brake state and the driver enters the cab, the parking brake light comes on to remind the driver that the vehicle cannot be driven without releasing the parking brake; In the driving priority mode, if the vehicle is in the parking brake and the driver still starts the engine, when the system detects that the engine starts and the wheels have a tendency to rotate, the vehicle automatically releases the parking brake and the vehicle can drive.

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