Hydraulic auxiliary controlled electric independent steering system and electric vehicle

Abstract

The present invention discloses an electric independent steering system and an electric vehicle with hydraulic auxiliary control, wherein the electric independent steering system comprises: an electric independent steering mechanism, a hydraulic control system and an electronic control unit; two groups of electric independent steering mechanisms are symmetrically distributed at the front and rear axle positions, the steering rocker arms of the two groups of electric independent steering assemblies are respectively connected to the piston connecting rods of the locking hydraulic cylinders, and the cylinder bodies of the two groups of symmetrically arranged locking hydraulic cylinders are coaxially fixedly connected through a central connecting rod; in the hydraulic control system, after the oil outlet of the hydraulic oil pump is connected to a one-way valve, the main oil circuit is divided into two front and rear oil circuits through a proportional diverter valve, and the oil circuits are respectively connected to the two groups of locking hydraulic cylinders through two three-position four-way solenoid valves; the electronic control unit is composed of a steering motor controller, a solenoid valve controller, a drive motor controller and a locking hydraulic cylinder linear displacement sensor connected through a CAN bus communication. The present invention can simultaneously improve the driving safety of the vehicle and the reliability of the electric independent steering system.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile independent steering control, and in particular relates to a hydraulically assisted electric independent steering system and an electric vehicle. Background Art

[0002] With the vigorous development of the global automobile industry, automobile intelligence and electrification have become a trend, and the requirements for automobile performance, technology, etc. are also increasing. The traditional mechanical structure of the automobile has changed, and the electric independent steering mechanism has appeared in the public eye.

[0003] Electric independent steering can be applied to various types of vehicles, especially distributed in-wheel drive electric vehicles, which eliminate components such as differentials and half shafts, have a more compact structure and high transmission efficiency, and can improve vehicle stability and other related performance when combined with ideal control algorithms. The emergence of electric independent steering meets the requirements of automobiles for high maneuverability, enables vehicles to achieve a variety of special steering modes, and has a very broad application prospect.

[0004] Although the electric independent steering mechanism in the prior art has many advantages, it also has defects.

[0005] For example, although the independent steering mechanism proposed in patent CN206125145U can meet different independent steering function requirements, most of its independent steering mechanism belongs to unsprung mass, and the layout of its steering mechanism will have an adverse effect on the vehicle's smoothness and handling stability.

[0006] In addition, although the independent steering mechanism involved in patent CN1702007A can realize four-wheel independent steering and independent control, and can ensure that the vehicle always rotates around the steering center during the steering process, reducing tire wear, its left and right wheel independent steering mechanism cancels the mechanical connection between the steering wheel and the steering mechanism, resulting in that when one side of the steering motor fails and loses its normal operation ability, the left and right steering wheels cannot be converted from independent movement to overall movement, thereby greatly reducing the vehicle's driving safety and smoothness. Summary of the invention

[0007] In view of the defects existing in the above-mentioned prior art, the present invention provides an electric independent steering system and an electric vehicle with hydraulic auxiliary control. The electric independent steering system of the present invention is mainly suitable for distributed electric vehicles with four-wheel independent steering, which can improve the driving safety of the vehicle and the reliability of the electric independent steering system. Combined with the drawings of the specification, the technical solution of the present invention is as follows:

[0008] An electric independent steering system with hydraulic auxiliary control, comprising: an electric independent steering mechanism, a hydraulic control system and an electronic control unit;

[0009] The two sets of electric independent steering mechanisms are symmetrically distributed at the front and rear axles;

[0010] In the electric independent steering mechanism, the steering motors in the two sets of electric independent steering assemblies are respectively connected to the steering rocker arms through worm gear reducers, the steering rocker arms are respectively connected to the piston connecting rods of the locking hydraulic cylinders, and the cylinder bodies of the two sets of symmetrically arranged locking hydraulic cylinders are coaxially fixedly connected through a central connecting rod;

[0011] In the hydraulic control system, the drive motor is mechanically connected to the hydraulic oil pump, the hydraulic oil pump outlet is connected to a one-way valve, and the main oil circuit is divided into two front and rear oil circuits through a proportional diverter valve. The front and rear oil circuits are respectively connected to two sets of locking hydraulic cylinders corresponding to the front and rear axles through two three-position four-way solenoid valves;

[0012] The electronic control unit is composed of a steering motor controller, a solenoid valve controller, a drive motor controller and a locking hydraulic cylinder linear displacement sensor connected via a CAN bus communication.

[0013] Furthermore, in the hydraulic control system, the oil outlet of the hydraulic oil pump is divided into two paths, one of which is connected to the one-way valve, and the other is connected to the overflow valve, and the overflow port of the overflow valve is connected to the oil tank.

[0014] Further, in the hydraulic control system, there are three groups of proportional diverter valves;

[0015] The oil outlet of the hydraulic oil pump is connected to the one-way valve and then connected to the first proportional diverter valve to form a main oil circuit. The oil outlet of the first proportional diverter valve is connected to the second proportional diverter valve and the third proportional diverter valve respectively, dividing the main oil into two front and rear oil circuits.

[0016] Furthermore, one oil outlet of the second proportional diverter valve is connected to the locking hydraulic cylinder pipeline corresponding to the wheel on one side of the front axle through the first three-position four-way solenoid valve, and the other oil outlet of the second proportional diverter valve is connected to the locking hydraulic cylinder pipeline corresponding to the wheel on the other side of the front axle through the second three-position four-way solenoid valve;

[0017] One oil outlet of the third proportional diverter valve is connected to the locking hydraulic cylinder pipeline corresponding to the wheel on one side of the rear axle through the third three-position four-way solenoid valve, and the other oil outlet of the third proportional diverter valve is connected to the locking hydraulic cylinder pipeline corresponding to the wheel on the other side of the rear axle through the fourth three-position four-way solenoid valve.

[0018] Furthermore, an accumulator is connected to the main oil circuit between the oil outlet of the hydraulic oil pump and the one-way valve.

[0019] Furthermore, the accumulator is an airbag accumulator.

[0020] An electric vehicle, wherein the steering system of the electric vehicle is the hydraulically assisted electric independent steering system;

[0021] The two sets of electric independent steering mechanisms of the electric independent steering system are symmetrically arranged at the front axle and rear axle positions of the vehicle chassis respectively;

[0022] In the electric independent steering mechanism, the end of the steering rocker arm is hinged to one end of the steering tie rod through the steering ball head, and the other end of the steering tie rod is hinged to the lateral ball head of the steering knuckle assembly, so as to drive the wheel to rotate around the kingpin by controlling the steering knuckle assembly;

[0023] The hydraulic control system is arranged on the frame and chassis of the vehicle.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. In the electric independent steering system described in the present invention, the electric independent steering mechanism uses a rocker arm pull rod mechanism in conjunction with a hydraulic locking mechanism, which can enable the vehicle to achieve special driving modes such as lateral driving or on-the-spot steering in a limited space, thereby improving the space utilization rate of the chassis and the maneuverability of the vehicle, and does not belong to the unsprung mass. In addition, the electric control steering process takes into account the side slip characteristics of the tire, and can adjust the steering angles of the left and right steering wheels respectively to reduce tire wear.

[0026] 2. In the electric independent steering system described in the present invention, the steering hydraulic control system provided can assist the electric steering mechanism in precise steering and has an emergency locking function, thereby improving the driving safety of the vehicle.

[0027] 3. The electric independent steering system of the present invention still has an Ackerman steering relationship after the hydraulic cylinder is locked, and at the same time realizes precise control of the wheel angle and is easy to operate;

[0028] 4. In the electric independent steering system described in the present invention, the electronic hydraulic control responds quickly and can meet the requirements of rapid response of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of an electric independent steering mechanism and a hydraulic control system in the electric independent steering system of the present invention;

[0030] Figure 2 A schematic structural diagram of an electric independent steering mechanism in the electric independent steering system of the present invention;

[0031] Figure 3 It is a structural schematic diagram of a hydraulic control system in the electric independent steering system of the present invention;

[0032] Figure 4A schematic diagram of the installation structure of the locking hydraulic cylinder in the electric independent steering system of the present invention;

[0033] Figure 5 A schematic diagram of control connection between an electronic control unit and an electric independent steering mechanism corresponding to a front axle in the electric independent steering system of the present invention;

[0034] In the figure:

[0035] 1-wheel, 2-steering knuckle assembly, 3-electric independent steering assembly,

[0036] 4-locking hydraulic cylinder, 5-steering tie rod, 8-accumulator,

[0037] 9- one-way valve, 10- overflow valve, 11- hydraulic oil pump,

[0038] 12-Oil tank, 13-Drive motor, 14-Main oil circuit,

[0039] 15-bolt connection seat, 18-drive motor controller;

[0040] 301-steering rocker arm, 302-steering bearing seat, 303-piston connecting rod,

[0041] 304-bolt connector, 305-worm gear reducer, 306-steering ball head,

[0042] 307-support seat, 308-steering motor, 309-central connecting rod;

[0043] 601-first solenoid valve, 602-second solenoid valve, 603-third solenoid valve,

[0044] 604- fourth solenoid valve;

[0045] 701-first proportional diverter valve, 702-second proportional diverter valve, 703-third proportional diverter valve;

[0046] 3081-right steering motor, 3082-left steering motor,

[0047] 1601-first steering motor controller, 1602-second steering motor controller;

[0048] 1701-first solenoid valve controller, 1702-second solenoid valve controller, DETAILED DESCRIPTION

[0049] In order to clearly and completely describe the technical solution and its specific working process of the present invention, the specific implementation methods of the present invention are as follows in conjunction with the accompanying drawings of the specification:

[0050] Embodiment 1:

[0051] The first embodiment discloses an electric independent steering system with hydraulic auxiliary control, including: an electric independent steering mechanism, a hydraulic control system and an electronic control unit.

[0052] There are two groups of electric independent steering mechanisms, which are arranged at the front axle and rear axle of the vehicle chassis respectively. Take the electric independent steering mechanism arranged at the front axle as an example:

[0053] like Figure 2 As shown, the electric independent steering mechanism includes: two sets of electric independent steering assemblies 3, locking hydraulic cylinders 4 respectively connected to the two sets of electric independent steering assemblies 3 in a one-to-one correspondence, and a central connecting rod 309 connected between the two locking hydraulic cylinders 4;

[0054] The electric independent steering assembly 3 is composed of a steering motor 308, a worm gear reducer 305 and a steering rocker arm 301; wherein, the outer shell of the steering motor 308 is fixed to the vehicle body through a bearing seat 307, the outer shell of the worm gear reducer 305 is fixed to the vehicle body, the output shaft of the steering motor 308 is coaxially connected with the worm of the worm gear reducer 305, thereby driving the worm to rotate, the worm wheel of the worm gear reducer 305 is meshingly connected with the worm, one end of the steering rocker arm 301 is coaxially mounted on the worm wheel shaft of the worm gear reducer 305, the worm wheel shaft is mounted on the vehicle body through a steering bearing seat 302, and the other end of the steering rocker arm 301 is provided with a steering ball head 306 for being hinged to the front axle steering tie rod assembly of the vehicle;

[0055] like Figure 2 and Figure 4 As shown, the two sets of electric independent steering assemblies 3 are symmetrically arranged on the left and right sides of the front axle, and the two locking hydraulic cylinders 4 are coaxially arranged between the two sets of electric independent steering assemblies 3. The end of the piston connecting rod 303 serving as the push-pull end of the locking hydraulic cylinder 4 is hinged to the middle of the steering rocker arm 301 through a bolt connector 304;

[0056] The two ends of the central connecting rod 309 are coaxially fixedly connected to the bottom of the cylinder body of two symmetrically arranged locking hydraulic cylinders 4 to realize the mechanical connection of the two sets of electric independent steering assemblies 3; when the steering motor 308 corresponding to the electric independent steering mechanism works normally, the cylinder body and the piston connecting rod 303 of the locking hydraulic cylinder 4 move with the steering rocker arm 301 connected to them respectively, and when the electronic control element on one side fails due to a fault, the locking hydraulic cylinder 4 on the faulty side and the corresponding locking hydraulic cylinder 4 on the other side are both locked through the operation of the steering hydraulic control system and the electronic control unit, and the mechanical structure on the faulty side is locked with the other side, so that the electric independent steering mechanism becomes a rigidly connected integrated mechanical structure, so that the vehicle still has steering capability.

[0057] like Figure 1 and Figure 3 As shown, the hydraulic control system includes: a drive motor 13, a hydraulic oil pump 11, an oil tank 12, a main oil circuit 14, a one-way valve 9, an accumulator 8, a relief valve 10, a proportional diverter valve, a solenoid valve and a locking hydraulic cylinder 4;

[0058] The proportional diverter valves include three groups, namely: a first proportional diverter valve 701, a second proportional diverter valve 702 and a third proportional diverter valve 703;

[0059] There are four groups of solenoid valves, namely the first solenoid valve 601, the second solenoid valve 602, the third solenoid valve 603 and the fourth solenoid valve 604. The first solenoid valve 601, the second solenoid valve 602, the third solenoid valve 603 and the fourth solenoid valve 604 are all three-position four-way solenoid valves;

[0060] As mentioned above, there are four groups of locking hydraulic cylinders 4, which are respectively connected to two groups of electric independent steering assemblies 3 in the electric independent steering mechanism located at the front axle of the vehicle, and two groups of electric independent steering assemblies 3 in the electric independent steering mechanism located at the rear axle of the vehicle;

[0061] The output end of the driving motor 13 is drivingly connected to the mechanical connection end of the hydraulic oil pump 11, the oil inlet of the hydraulic oil pump 11 is connected to the pipeline of the oil tank 12, and the oil outlet of the hydraulic oil pump 11 is divided into two paths, wherein one path of the oil outlet of the hydraulic oil pump 11 is connected to the pipeline of the overflow valve 10, and the overflow port of the overflow valve 10 is connected to the pipeline of the oil tank 12. When the pipeline pressure of the hydraulic control system is too large, the overflow valve 10 opens and returns part of the hydraulic oil in the pipeline to the oil tank 12, so as to maintain the pipeline pressure of the hydraulic control system stable within a certain value range; the other path of the oil outlet of the hydraulic oil pump 11 is connected to the pipeline of the one-way valve 9, and the one-way valve 9 is set to be unidirectionally conducted from the hydraulic oil pump 11 to the outside, so as to prevent the hydraulic oil from flowing back and realize the direction control of the main oil circuit 14;

[0062] The downstream of the one-way valve 9 is connected to the first proportional flow divider valve 701 through the main oil circuit 14, and the oil pipeline of the accumulator 8 is connected to the main oil circuit 14 between the one-way valve 9 and the first proportional flow divider valve 701 through a threaded interface. According to the overall structure and characteristics of the hydraulic control system, the accumulator 8 adopts a bladder accumulator;

[0063] When the locking hydraulic cylinder 4 is locked due to a fault in the electric independent steering mechanism assembly 3 on one side of the electric independent steering mechanism, the accumulator 8 will be energized to absorb the oil impact generated in the hydraulic control system in time, and can compensate for the leakage of hydraulic oil in the hydraulic control system pipeline to maintain the overall pressure of the hydraulic control system pipeline;

[0064] The main oil circuit 14 is divided into two circuits after passing through the first proportional diverter valve 701, and is respectively connected to the second proportional diverter valve 702 and the third proportional diverter valve 703, wherein the two oil outlets of the second proportional diverter valve 702 are respectively connected to the first solenoid valve 601 and the second solenoid valve 602, and the two oil outlets of the third proportional diverter valve 703 are respectively connected to the third solenoid valve 603 and the fourth solenoid valve 604;

[0065] like Figure 3 As shown, the first solenoid valve 601, the second solenoid valve 602, the third solenoid valve 603 and the fourth solenoid valve 604 are respectively installed between the corresponding proportional diverter valve and the locking hydraulic cylinder, and the connection relationship between each solenoid valve and the corresponding proportional diverter valve and the locking hydraulic cylinder is the same. Taking the second solenoid valve 602 as an example:

[0066] The second solenoid valve 602 has three working positions and four connection ports, and the four connection ports are respectively: port A, port B, port C and port D; wherein the port A of the second solenoid valve 602 is connected to the oil outlet pipeline of the first proportional diverter valve 702, the port C of the second solenoid valve 602 is connected to the rod chamber oil outlet pipeline of the locking hydraulic cylinder 4, the port D of the second solenoid valve 602 is connected to the rodless chamber oil outlet pipeline of the locking hydraulic cylinder 4, and the port B of the second solenoid valve 602 is connected to the pipeline of the oil tank 12;

[0067] When the left coil of the second solenoid valve 602 is energized and in the first working position, that is, Figure 3 In the working position on the left side of the second solenoid valve 602, the hydraulic oil flows out through the first proportional diverter valve 702, flows in through the A port of the second solenoid valve 602, and flows out from the C port of the second solenoid valve 602 to the rod chamber of the locking hydraulic cylinder 4. Under the pressure of the hydraulic oil, the piston of the locking hydraulic cylinder 4 drives the piston connecting rod to move toward the rodless chamber. The hydraulic oil in the rodless chamber of the locking hydraulic cylinder 4 flows out through the rodless chamber oil port, flows in through the D port of the second solenoid valve 602, and flows out from the B port of the second solenoid valve 602 to the oil tank. At this time, since the piston of the locking hydraulic cylinder 4 drives the piston connecting rod to move toward the rodless chamber, that is, the piston of the locking hydraulic cylinder 4 drives the piston connecting rod to move rightward, the locking hydraulic cylinder 4 assists in cooperating with the electric independent steering assembly to control the corresponding wheel to turn left.

[0068] When the right coil of the second solenoid valve 602 is energized and in the second working position, that is, Figure 3In the working position on the right side of the second solenoid valve 602, the hydraulic oil flows out through the first proportional diverter valve 702, flows in through the A port of the second solenoid valve 602, and flows out from the D port of the second solenoid valve 602 to the rodless chamber of the locking hydraulic cylinder 4. Under the pressure of the hydraulic oil, the piston of the locking hydraulic cylinder 4 drives the piston connecting rod to move toward the side of the rod chamber. The hydraulic oil in the rod chamber of the locking hydraulic cylinder 4 flows out through the rod chamber oil port, flows in through the C port of the second solenoid valve 602, and flows out from the B port of the second solenoid valve 602 to the oil tank. At this time, since the piston of the locking hydraulic cylinder 4 drives the piston connecting rod to move toward the side of the rod chamber, that is, the piston of the locking hydraulic cylinder 4 drives the piston connecting rod to move leftward, the locking hydraulic cylinder 4 assists the electric independent steering assembly to control the corresponding wheel to turn right.

[0069] When the second solenoid valve 602 is in a state of being powered off Figure 3 In the middle third working position shown, the A port, B port, C port and D port of the second solenoid valve 602 are all closed and not conducting, no liquid oil flows in the rod chamber and the rodless chamber of the locking hydraulic cylinder 4, and the locking hydraulic cylinder 4 is in a locked state.

[0070] The electronic control unit includes: a steering motor controller (SCU), a solenoid valve controller (VCU), a drive motor controller (DCU) and a linear displacement measurement component, wherein:

[0071] There are four steering motor controllers, which respectively control the action outputs of the steering motors in four sets of electric independent steering assemblies located on both sides of the front axle and the rear axle of the vehicle. The connection structures and control processes of the four sets of steering motor controllers and the steering motors are the same;

[0072] There are four solenoid valve controllers, which respectively control the actions of four groups of solenoid valves. The connection structures and control processes of the four groups of solenoid valve controllers and the solenoid valves are the same;

[0073] The drive motor controller has one, which is used to control the action output of the drive motor in the hydraulic control system;

[0074] The linear displacement measurement assembly is composed of four groups of linear displacement sensors, each group of displacement sensors is correspondingly installed on a locking hydraulic cylinder to detect the displacement of the piston in the corresponding locking hydraulic cylinder, and then indirectly obtain the corresponding wheel angle. The installation and connection methods and information collection processes of the four groups of displacement sensors and the locking hydraulic cylinder are the same;

[0075] Take the front axle of a vehicle as an example:

[0076] In the electronic control unit, the drive motor controller (DCU1) 18 is connected to the drive motor 13 control signal; the first steering motor controller (SCU1) 1601 is connected to the right steering motor 3801 control signal, and the second steering motor controller (SCU2) 1602 is connected to the left steering motor 3802 control signal; the first solenoid valve controller (VCU1) 1701 is connected to the first solenoid valve 601 control signal, and the second solenoid valve controller (VCU2) 1702 is connected to the second solenoid valve 602 control signal;

[0077] The first displacement sensor (not shown in the figure) is correspondingly installed on the right locking hydraulic cylinder, and the second displacement sensor (not shown in the figure) is correspondingly installed on the left locking hydraulic cylinder;

[0078] The drive motor controller 18, the first steering motor controller 1601, the second steering motor controller 1602, the first solenoid valve controller 1701, the second solenoid valve controller 1702, the first displacement sensor and the second displacement sensor all communicate via a CAN bus;

[0079] The first displacement sensor and the second displacement sensor respectively feed back the detected linear displacement of the corresponding pistons of the right locking hydraulic cylinder and the left locking hydraulic cylinder, that is, the turning angle of the corresponding wheels, to the electronic control unit through the CAN bus. The single control unit provides a voltage control signal to the first solenoid valve controller 1701 and the second solenoid valve controller 1702 through the CAN bus. The first solenoid valve 601 and the second solenoid valve 602 control the valve opening according to the control voltage input by the first solenoid valve controller 1701 and the second solenoid valve controller 1702, thereby controlling the hydraulic oil flow into the corresponding locking hydraulic cylinder 4.

[0080] The working process of the hydraulically assisted electric independent steering system described in the first embodiment is briefly described as follows:

[0081] Take the front axle of a vehicle as an example:

[0082] When the electric independent steering assembly of the front axle works normally, under the drive of the corresponding steering motor 308, the steering rocker arm 301 is controlled to swing through the worm gear reducer 305, thereby realizing the steering of the corresponding wheel. At the same time, under the control of the hydraulic control system and the electronic control unit, the piston connecting rod in the locking hydraulic cylinder 4 is extended and retracted accordingly, thereby assisting the rotation of the wheel.

[0083] When the electric independent steering assembly on one side of the front axle fails, the first solenoid valve controller 1701 and the second solenoid valve controller 1702 receive relevant information from the CAN bus, control the first solenoid valve 601 and the second solenoid valve 602 to cut off power in time, and close the first solenoid valve 601 and the second solenoid valve 602, so that the first solenoid valve 601 and the second solenoid valve 602 are both in the middle working position, and the locking hydraulic cylinder 4 on the left and right sides of the front axle are locked. At this time, the left and right electric independent steering assemblies are mechanically connected to ensure that the vehicle can steer normally.

[0084] During the vehicle turning process, the first steering motor controller 1601 and the second steering motor controller 1602 receive relevant information such as the steering wheel angle and the vehicle speed from the CAN bus. Based on the existing structure and taking into account the tire side slip characteristics, the right steering motor 3081 and the left steering motor 3802 are controlled to rotate respectively, and the steering angles of the corresponding wheels are adjusted so that the centers of the left and right wheel motion trajectories coincide with each other, thereby reducing tire wear.

[0085] When the vehicle encounters extreme working conditions or emergency working conditions, such as emergency steering, sudden lane change, etc., the yaw angular velocity of the vehicle increases sharply, and it is difficult for the driver to control the vehicle in this case. At this time, the first steering motor controller 1601 and the second steering motor controller 1602 receive various vehicle state information through the CAN bus, judge the vehicle driving conditions, and control the speed and angle of the right steering motor 3081 and the left steering motor 3802 respectively, correct the driving path of the vehicle, and improve the driving safety of the vehicle.

[0086] When the vehicle is about to perform a special steering condition, such as lateral movement or turning on the spot, the first steering motor controller 1601 and the second steering motor controller 1602 can control the steering angles of the right steering motor 3081 and the left steering motor 3802 respectively according to the control strategy set by the system.

[0087] The control circuit is equipped with a system fault diagnosis element, which will alarm when a fault occurs in the steering system.

[0088] Embodiment 2:

[0089] The second embodiment discloses an electric vehicle, which is a distributed electric vehicle with four-wheel independent steering. The steering system of the electric vehicle adopts the hydraulically assisted electric independent steering system described in the first embodiment.

[0090] like Figure 1 and Figure 2 As shown, in the electric independent steering system, two sets of electric independent steering mechanisms are respectively arranged at the front axle and rear axle positions of the vehicle chassis. Taking the electric independent steering mechanism arranged at the front axle position as an example:

[0091] In the electric independent steering assembly 3 located at the left and right ends of the front axle, take the left side of the front axle as an example:

[0092] The steering ball head 306 is hinged to one end of the steering tie rod 5, and the other end of the steering tie rod 5 is hinged to the lateral ball head on the steering knuckle assembly 2 on the corresponding side, so as to realize the rotation of the wheel 1 around the kingpin by controlling the steering knuckle assembly 2.

[0093] The hydraulic control system is installed on the vehicle frame and the chassis.

Claims

1. An electric independent steering system with hydraulic auxiliary control, characterized in that: include: Electric independent steering mechanism, hydraulic control system and electronic control unit; The two sets of electric independent steering mechanisms are symmetrically distributed at the front and rear axles; In the electric independent steering mechanism, the steering motors in the two sets of electric independent steering assemblies are respectively connected to the steering rocker arms through worm gear reducers, the steering rocker arms are respectively connected to the piston connecting rods of the locking hydraulic cylinders, and the cylinder bodies of the two sets of symmetrically arranged locking hydraulic cylinders are coaxially fixedly connected through a central connecting rod; In the hydraulic control system, the drive motor is mechanically connected to the hydraulic oil pump, the hydraulic oil pump outlet is connected to a one-way valve, and the main oil circuit is divided into two front and rear oil circuits through a proportional diverter valve. The front and rear oil circuits are respectively connected to two sets of locking hydraulic cylinders corresponding to the front and rear axles through two three-position four-way solenoid valves; The electronic control unit is composed of a steering motor controller, a solenoid valve controller, a drive motor controller and a locking hydraulic cylinder linear displacement sensor connected via a CAN bus communication; In the hydraulic control system, the oil outlet of the hydraulic oil pump is divided into two paths, one of which is connected to the one-way valve, and the other is connected to the overflow valve, and the overflow port of the overflow valve is connected to the oil tank; In the hydraulic control system, there are three groups of proportional diverter valves; The oil outlet of the hydraulic oil pump is connected to the one-way valve and then connected to the first proportional diverter valve to form a main oil circuit. The oil outlet of the first proportional diverter valve is connected to the second proportional diverter valve and the third proportional diverter valve respectively, dividing the main oil circuit into two front and rear oil circuits. One oil outlet of the second proportional diverter valve is connected to the locking hydraulic cylinder pipeline corresponding to the wheel on one side of the front axle through the first three-position four-way solenoid valve, and the other oil outlet of the second proportional diverter valve is connected to the locking hydraulic cylinder pipeline corresponding to the wheel on the other side of the front axle through the second three-position four-way solenoid valve; One oil outlet of the third proportional diverter valve is connected to the locking hydraulic cylinder pipeline corresponding to the wheel on one side of the rear axle through the third three-position four-way solenoid valve, and the other oil outlet of the third proportional diverter valve is connected to the locking hydraulic cylinder pipeline corresponding to the wheel on the other side of the rear axle through the fourth three-position four-way solenoid valve; an accumulator is connected to the main oil circuit between the oil outlet of the hydraulic oil pump and the one-way valve, and the accumulator is an airbag accumulator; When the electric independent steering assembly of the front axle works normally, the steering rocker arm is controlled to swing through the worm gear reducer under the drive of the corresponding steering motor, and the corresponding wheel turns. Under the control of the hydraulic control system and the electronic control unit, the piston connecting rod in the locking hydraulic cylinder is extended and retracted accordingly to assist the wheel rotation; When the electric independent steering assembly on one side of the front axle fails, the first solenoid valve controller and the second solenoid valve controller receive relevant information from the CAN bus, control the first solenoid valve and the second solenoid valve to be powered off in time, and close the first solenoid valve and the second solenoid valve, so that the first solenoid valve and the second solenoid valve are both in the middle working position, the locking hydraulic cylinders on the left and right sides of the front axle are locked, and the left and right electric independent steering assemblies are mechanically connected; When the vehicle is turning, the first steering motor controller and the second steering motor controller receive information related to the steering wheel angle and vehicle speed from the CAN bus, and respectively control the right steering motor and the left steering motor to rotate, and adjust the steering angles of the corresponding wheels so that the centers of the left and right wheel motion trajectories coincide with each other; When the vehicle encounters extreme working conditions or emergency working conditions, the first steering motor controller and the second steering motor controller receive various vehicle status information through the CAN bus, judge the vehicle driving conditions, and control the speed and angle of the right steering motor and the left steering motor respectively to correct the vehicle's driving path; When the vehicle is about to perform a special steering condition, the first steering motor controller and the second steering motor controller respectively control the steering angles of the right steering motor and the left steering motor according to the control strategy set by the system; The control circuit is equipped with a system fault diagnosis element, which will alarm when a fault occurs in the steering system.

2. An electric vehicle, characterized in that: The steering system of the electric vehicle is the hydraulically assisted electric independent steering system as claimed in claim 1; The two sets of electric independent steering mechanisms of the electric independent steering system are symmetrically arranged at the front axle and rear axle positions of the vehicle chassis respectively; In the electric independent steering mechanism, the end of the steering rocker arm is hinged to one end of the steering tie rod through the steering ball head, and the other end of the steering tie rod is hinged to the lateral ball head of the steering knuckle assembly, so as to drive the wheel to rotate around the kingpin by controlling the steering knuckle assembly; The hydraulic control system is arranged on the frame and chassis of the vehicle.

Images