Independent steer-by-wire-brake electro-hydrostatic execution system for electric wheel

Abstract

The invention provides an independent steer-by-wire brake electro-hydrostatic execution system for an electric wheel. The independent steer-by-wire brake electro-hydrostatic execution system comprises a backup servo pump, a steering servo pump, a brake servo pump, a normally-closed electromagnetic valve group, an oil can, a switch valve group, a steering hydraulic motor and a steering mounting block. The steering servo pump and the braking servo pump directly drive one steering hydraulic motor and one braking wheel cylinder through volume servo control, and independent steering and braking of electric wheels are achieved. The backup servo pump is in time-sharing connection with a steering hydraulic loop and a braking hydraulic loop through a normally-closed electromagnetic valve group and provides backup hydraulic power; a rotor of the steering hydraulic motor drives the steering belt to rotate, and a stator of the steering hydraulic motor is connected with the frame through a steering mounting block. According to the independent steer-by-wire-brake electro-hydrostatic execution system for the electric wheel, the pump control direct drive technology is adopted, and high efficiency and energy saving are achieved; a redundant local integrated hydraulic system is formed, the reliability is high, the unsprung mass is effectively reduced, and a new scheme is provided for independent steering and braking of electric wheels.

Description

Technical Field

[0001] The present invention mainly relates to the technical field related to vehicle wire control, and specifically to an independent wire-controlled steering-brake electrostatic hydraulic actuation system for electric wheels. Background Art

[0002] Automotive drive-by-wire technology is a crucial foundation for achieving intelligent and connected vehicles. Electric wheels, which integrate steering, braking, drive, and suspension systems, are also one of the most promising areas for automotive development. Traditional drive-by-wire systems, often retrofitted from existing steering and braking systems, struggle to achieve independent steering and braking control for electric wheels, limiting their advantages.

[0003] Currently, electric wheels with integrated steering, braking, drive, and suspension systems often use electromechanical braking and steering systems to independently control braking and steering. Electromechanical braking systems utilize a rotary motor acceleration and deceleration mechanism coupled with a motion conversion mechanism to control braking force, while electromechanical steering systems utilize a rotary motor acceleration and deceleration mechanism to control steering angle. The shortcomings of traditional solutions include: 1) designing a backup power system for system redundancy is difficult, and the safety of the drive-by-wire system needs to be improved; 2) when steering torque and braking force requirements are high, the electromechanical system is bulky and difficult to install within the limited integrated installation space; 3) the mass of the braking and steering systems is entirely unsprung, further exacerbating the unsprung mass of electric wheel vehicles and impacting vehicle dynamics. Summary of the Invention

[0004] To address the deficiencies in current technology, the present invention combines existing technology with practical application to provide an independent wire-controlled steering-brake electrostatic actuator system for electric wheels. The main components of the steering-brake system are integrated into a hydraulic module and fixedly installed on the vehicle frame adjacent to the electric wheel. The steering hydraulic pump drives the steering junction without changing the existing brake wheel cylinder structure, providing more space for the electric wheel inner drive and suspension system design, while effectively reducing the mass under the electric wheel spring; a steering servo pump and a brake servo pump are respectively directly driven by a steering hydraulic motor and a brake wheel cylinder through volume servo control, shortening the power transmission path and achieving high efficiency and energy saving; a backup servo pump is designed to provide backup power for the steering and braking systems, effectively improving system reliability.

[0005] The technical solutions of the present invention are as follows: An independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels includes a steering servo pump, a brake servo pump, a steering hydraulic motor, and a steering mounting block. The rotor of the steering hydraulic motor drives the steering joint to rotate, and the stator of the steering hydraulic motor is connected to the vehicle frame via the steering mounting block. It also includes a spare servo pump and an oil tank. The first oil port of the steering servo pump is connected to the first one-way valve and the first oil port of the steering hydraulic motor, and the second oil port of the steering servo pump is connected to the second one-way valve and the second oil port of the steering hydraulic motor; The two oil ports of the brake servo pump are connected to the brake wheel cylinder and the oil pot respectively; The first oil port of the standby servo pump is connected to the first oil port of the steering hydraulic motor through the first normally closed solenoid valve, and is connected to the oil tank through the third normally closed solenoid valve. The second oil port of the standby servo pump is connected to the second oil port of the steering hydraulic motor through the second normally closed solenoid valve, and is connected to the brake wheel cylinder through the fourth normally closed solenoid valve. The oil pot is connected to the two oil ports of the steering servo pump through a first one-way valve and a second one-way valve respectively, and is used to replenish oil for the steering hydraulic circuit.

[0006] Furthermore, the first normally closed solenoid valve is not opened at the same time as the third normally closed solenoid valve, but is opened at the same time as the second normally closed solenoid valve; the fourth normally closed solenoid valve is not opened at the same time as the second normally closed solenoid valve, but is opened at the same time as the third normally closed solenoid valve.

[0007] Furthermore, the execution system has three working modes, as follows: In normal working mode, the auxiliary servo pump, the first normally closed solenoid valve, the second normally closed solenoid valve, the third normally closed solenoid valve, and the fourth normally closed solenoid valve do not work. According to the controller's instructions, the steering servo pump directly drives the rotor of the steering hydraulic motor to drive the steering knot to rotate, and the brake servo pump directly controls the pressure in the brake wheel cylinder to achieve independent control of single electric wheel steering and braking; In the steering backup mode, if the steering servo pump fails, the third and fourth normally closed solenoid valves do not work, and the first and second normally closed solenoid valves are open. According to the controller instructions, the backup servo pump directly drives the rotor of the steering hydraulic motor to drive the steering knot to rotate, and the brake servo pump directly controls the pressure in the brake wheel cylinder to achieve independent control of single electric wheel steering and braking; In the brake backup mode, the brake servo pump fails, the first normally closed solenoid valve and the second solenoid valve do not work, the third normally closed solenoid valve and the fourth normally closed solenoid valve are open. According to the controller instructions, the steering servo pump directly drives the rotor of the steering hydraulic motor to drive the steering knot to rotate, and the backup servo pump directly controls the pressure in the brake wheel cylinder to achieve independent control of single electric wheel steering and braking.

[0008] Furthermore, the backup servo pump, steering servo pump, brake servo pump, first normally closed solenoid valve, second normally closed solenoid valve, third normally closed solenoid valve, fourth normally closed solenoid valve, oil tank, first one-way valve, and second one-way valve are integrated into a hydraulic module and fixedly installed on the frame adjacent to the electric wheel.

[0009] Furthermore, the standby servo pump, steering servo pump, and brake servo pump are all double-acting direct-drive hydraulic pumps whose hydraulic pump movers are directly driven by motors.

[0010] Furthermore, the rotor of the steering hydraulic motor drives the steering knot to rotate by an angle less than or equal to 360°.

[0011] Beneficial effects of the present invention: 1. The present invention provides an independent wire-controlled steering-brake electrostatic hydraulic actuator system for an electric wheel. The main components are integrated into a hydraulic module fixedly mounted on the vehicle frame adjacent to the electric wheel. The steering hydraulic pump drives the steering joint without changing the existing brake wheel cylinder structure. This provides more space for the design of the electric wheel's inner drive and suspension system, while effectively reducing the unsprung mass of the electric wheel.

[0012] 2. The present invention provides an independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels, which adopts a steering servo pump and a brake servo pump to directly drive a steering hydraulic motor and a brake wheel cylinder respectively through volume servo control, shortening the power transmission path, eliminating the throttling loss of the valve-controlled hydraulic system, and achieving high efficiency and energy saving.

[0013] 3. The present invention provides an independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels, and a backup servo pump is designed to provide backup power for the steering and braking systems at the same time, effectively improving system reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of an independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels of the present invention Figure 2 Schematic diagram of the hydraulic circuit for the electric wheel's independent steer-by-wire brake electrostatic actuator system in steering backup mode Figure 3 Schematic diagram of the hydraulic circuit for the electric wheel's independent steer-by-wire brake electrostatic actuator system in brake backup mode. DETAILED DESCRIPTION

[0015] The present invention will be further described with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the present application.

[0016] like Figure 1 As shown, the present invention provides an independent wire-controlled steering-brake electrostatic hydraulic actuation system for electric wheels.

[0017] This system mainly includes a standby servo pump 1, a steering servo pump 2, a brake servo pump 3, a first normally closed solenoid valve 4.1, a second normally closed solenoid valve 4.2, a third normally closed solenoid valve 4.3, a fourth normally closed solenoid valve 4.4, an oil tank 5, a first one-way valve 6.1, a second one-way valve 6.2, a steering hydraulic motor 7, and a steering mounting block 8.

[0018] The hydraulic module includes a backup servo pump 1, a steering servo pump 2, a brake servo pump 3, a first normally closed solenoid valve 4.1, a second normally closed solenoid valve 4.2, a third normally closed solenoid valve 4.3, a fourth normally closed solenoid valve 4.4, an oil tank 5, a first one-way valve 6.1, and a second one-way valve 6.2, which are integrated into a hydraulic module and fixedly installed on the frame adjacent to the electric wheel.

[0019] The two oil ports of the steering servo pump 2 are respectively connected to the one-way valve 6.1, the one-way valve 6.2 and the two oil ports of the steering hydraulic motor 7. The two oil ports of the brake servo pump 3 are respectively connected to the brake wheel cylinder and the oil pot 5. The first oil port of the auxiliary servo pump 1 is respectively connected to the first oil port of the steering hydraulic motor 7 and the oil pot 5 through the first normally closed solenoid valve 4.1 and the third normally closed solenoid valve 4.3. The second oil port of the auxiliary servo pump 1 is respectively connected to the second oil port of the steering hydraulic motor 7 and the brake wheel cylinder through the second normally closed solenoid valve 4.2 and the fourth normally closed solenoid valve 4.4. The oil pot 5 is respectively connected to the two oil ports of the steering servo pump 2 through the first one-way valve 6.1 and the second one-way valve 6.2 to replenish oil for the steering hydraulic circuit. The rotor 7.2 of the steering hydraulic motor drives the steering joint to rotate. The stator 7.1 of the steering hydraulic motor is connected to the vehicle frame through the steering mounting block 8. The first normally closed solenoid valve 4.1 is opened at different times from the third normally closed solenoid valve 4.3 and is opened at the same time as the second normally closed solenoid valve 4.2; the fourth normally closed solenoid valve 4.4 is opened at different times from the second normally closed solenoid valve 4.2 and is opened at the same time as the third normally closed solenoid valve 4.3.

[0020] In this embodiment, the standby servo pump 1 , the steering servo pump 2 , and the brake servo pump 3 are double-acting direct-drive hydraulic pumps in which the motor directly drives the hydraulic pump mover.

[0021] In this embodiment, the steering hydraulic motor rotor 7.2 drives the steering hitch to rotate by an angle less than or equal to 360°.

[0022] In this embodiment, the independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels has three operating modes: 1) Normal working mode: The standby servo pump 1, the first normally closed solenoid valve 4.1, the second normally closed solenoid valve 4.2, the third normally closed solenoid valve 4.3, and the fourth normally closed solenoid valve 4.4 are not working. According to the controller instructions, the steering servo pump 2 directly drives the rotor of the steering hydraulic motor 7 to drive the steering knot to rotate, and the brake servo pump 3 directly controls the pressure in the brake wheel cylinder to achieve independent control of the steering and braking of a single electric wheel.

[0023] 2) Steering backup mode: Steering servo pump 2 fails, the third normally closed solenoid valve 4.3 and the fourth normally closed solenoid valve 4.4 do not work, and the first normally closed solenoid valve 4.1 and the second normally closed solenoid valve 4.2 are open. According to the controller instructions, the backup servo pump 1 directly drives the rotor of the steering hydraulic motor 7 to drive the steering joint to rotate, and the brake servo pump 3 directly controls the pressure in the brake wheel cylinder to achieve independent control of the steering and braking of a single electric wheel. In the steering backup mode, the oil circuit of the electric wheel independent wire control steering-brake electrostatic actuator system is shown as follows Figure 2 , where the bold solid line represents the steering hydraulic circuit, and the bold dotted line represents the brake hydraulic circuit.

[0024] 3) Brake backup mode: Brake servo pump 3 fails, first normally closed solenoid valve 4.1 and second normally closed solenoid valve 4.2 do not work, third normally closed solenoid valve 4.3 and fourth normally closed solenoid valve 4.4 are open. According to the controller command, steering servo pump 2 directly drives the rotor of steering hydraulic motor 7 to drive the steering joint to rotate, and backup servo pump 1 directly controls the pressure in the brake wheel cylinder to achieve independent control of single electric wheel steering and braking. In steering backup mode, the oil circuit of the electric wheel independent wire control steering-brake electrostatic actuator system is shown as follows Figure 3 , where the bold solid line represents the steering hydraulic circuit, and the bold dotted line represents the brake hydraulic circuit.

[0025] The system in this embodiment uses a steering servo pump and a brake servo pump, respectively, directly driving a steering hydraulic motor and a wheel cylinder through volumetric servo control, shortening the power transmission path and achieving high efficiency and energy conservation. A backup servo pump is also designed to provide backup power for the steering and braking systems, effectively improving system reliability. This solves the problems of existing independent steer-by-wire and brake electrostatic hydraulic actuation systems, such as complex structure, high energy consumption, low reliability, and deterioration of unsprung mass.

Claims

1. An independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels, comprising a steering servo pump, a brake servo pump, a steering hydraulic motor, and a steering mounting block. The rotor of the steering hydraulic motor drives the steering joint to rotate, and the stator of the steering hydraulic motor is connected to the vehicle frame via the steering mounting block. The system is characterized in that: Also includes spare servo pump and oil pot: The first oil port of the steering servo pump is connected to the first one-way valve and the first oil port of the steering hydraulic motor, and the second oil port of the steering servo pump is connected to the second one-way valve and the second oil port of the steering hydraulic motor; The two oil ports of the brake servo pump are connected to the brake wheel cylinder and the oil pot respectively; The first oil port of the standby servo pump is connected to the first oil port of the steering hydraulic motor through the first normally closed solenoid valve, and is connected to the oil tank through the third normally closed solenoid valve. The second oil port of the standby servo pump is connected to the second oil port of the steering hydraulic motor through the second normally closed solenoid valve, and is connected to the brake wheel cylinder through the fourth normally closed solenoid valve. The oil pot is connected to the two oil ports of the steering servo pump through a first one-way valve and a second one-way valve respectively, and is used to replenish oil for the steering hydraulic circuit.

2. The independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels according to claim 1, characterized in that: The first normally closed solenoid valve is opened at different times from the third normally closed solenoid valve, but is opened at the same time as the second normally closed solenoid valve; the fourth normally closed solenoid valve is opened at different times from the second normally closed solenoid valve, but is opened at the same time as the third normally closed solenoid valve.

3. The independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels according to claim 1, characterized in that: The execution system has three working modes, as follows: In normal working mode, the auxiliary servo pump, the first normally closed solenoid valve, the second normally closed solenoid valve, the third normally closed solenoid valve, and the fourth normally closed solenoid valve do not work. According to the controller's instructions, the steering servo pump directly drives the rotor of the steering hydraulic motor to drive the steering knot to rotate, and the brake servo pump directly controls the pressure in the brake wheel cylinder to achieve independent control of single electric wheel steering and braking; In the steering backup mode, if the steering servo pump fails, the third and fourth normally closed solenoid valves do not work, and the first and second normally closed solenoid valves are open. According to the controller instructions, the backup servo pump directly drives the rotor of the steering hydraulic motor to drive the steering knot to rotate, and the brake servo pump directly controls the pressure in the brake wheel cylinder to achieve independent control of single electric wheel steering and braking; In the brake backup mode, the brake servo pump fails, the first normally closed solenoid valve and the second solenoid valve do not work, the third normally closed solenoid valve and the fourth normally closed solenoid valve are open. According to the controller instructions, the steering servo pump directly drives the rotor of the steering hydraulic motor to drive the steering knot to rotate, and the backup servo pump directly controls the pressure in the brake wheel cylinder to achieve independent control of single electric wheel steering and braking.

4. The independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels according to claim 1, characterized in that: The hydraulic module includes a spare servo pump, a steering servo pump, a brake servo pump, a first normally closed solenoid valve, a second normally closed solenoid valve, a third normally closed solenoid valve, a fourth normally closed solenoid valve, an oil tank, a first one-way valve, and a second one-way valve, which are integrated into a hydraulic module and fixedly installed on a frame adjacent to the electric wheel.

5. The independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels according to claim 1, characterized in that: The standby servo pump, steering servo pump, and brake servo pump are all double-acting direct-drive hydraulic pumps whose hydraulic pump movers are directly driven by motors.

6. The independent wire-controlled steering-brake electrostatic hydraulic actuator system for electric wheels according to claim 1, characterized in that: The rotor of the steering hydraulic motor drives the steering knot to rotate at an angle less than or equal to 360°.

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