CN203974929U - A kind of trailing wheel active steering apparatus and control system thereof - Google Patents

Abstract

The utility model discloses a rear wheel active steering device and its control system, comprising a torque amplification device assembly, a rear wheel steering system assembly, a steering knuckle and a wheel system assembly, and the steering knuckle is fixed on a hub motor of the wheel system assembly On the motor shaft of the rear wheel steering system assembly, the steering tie rod of the rear wheel steering system assembly is connected with the steering trapezoidal arm of the steering knuckle, and the bracket at the lower end of the torque amplification device assembly is connected with the steering drive shaft of the rear wheel steering system assembly. The utility model is applied to an electric vehicle independently driven by a wheel hub motor, and the rear wheel steering torque can be amplified by the torque amplification device to adapt to the occasion where steering is difficult. Adjustment can assist in realizing rear wheel steering.

Description

A rear wheel active steering device and its control system

technical field

The utility model relates to the field of electric vehicles, in particular to a rear wheel active steering device and a control system for the electric vehicle.

Background technique

With the sharp increase in the demand for petroleum resources in the automobile industry and the serious negative impact on the environment, the research on electric vehicles with the advantages of energy saving, environmental protection, and low noise has become the internal requirement and development trend of today's automobile industry. Among them, the hub motor independently drives the electric vehicle by integrating the motor and the hub, and the hub motor directly drives the wheel to rotate, eliminating the traditional transmission system, canceling the clutch, transmission and other components, improving the transmission efficiency and saving car space. Increased flexibility in vehicle design.

At the same time, with the development of the economy and the advancement of automobile technology, highway traffic presents a trend of high-speed driving, dense traffic flow and unprofessional drivers. Automobile traffic accidents have also brought a great threat to people's lives and properties, and it is directly related to the safety of people's lives and properties. How to improve automobile safety and reduce the number of casualties in traffic accidents has increasingly become a hot issue in the field of automobile research and design.

As a new method to improve vehicle dynamic performance, four-wheel steering technology has received more and more attention and application. Studies have shown that when the car is turning while driving, due to the lateral force, the front wheels have the characteristics of understeer, and the rear wheels have a tendency to oversteer. The latter will cause the car to lose the stability of steering. The higher the speed, the more obvious the problem, and even a side slip and rollover. The solution is generally to compensate by turning the rear wheels 1° to 2° in the same direction as the front wheels.

The current active rear wheel steering device of automobiles mainly adopts a linear stepper motor, which directly drives the rack and pinion steering mechanism on the rear wheel steering system assembly under the adjustment of the control system, and then realizes the steering of the rear wheels by pulling the steering rod. Turn at a small angle. However, for the current rear wheel active steering device, only relying on the linear stepper motor to drive the steering rod to move laterally, in some occasions that require a large steering torque, such as muddy roads or when large angle steering is required, it often has certain limitations.

Utility model content

Technical problem to be solved: Aiming at the deficiencies of the existing technology, the utility model proposes a rear wheel active steering device, which solves the problem that the existing automobile rear wheel active steering device cannot provide Technical problem with high steering torque.

Technical solution: In order to solve the above-mentioned technical problems, the utility model adopts the following technical solutions:

An active rear wheel steering device for an electric vehicle independently driven by an in-wheel motor, comprising a linear stepping motor, a torque amplification device assembly, a rear wheel steering system assembly, a steering knuckle, and a rear wheel wheel system assembly;

The steering knuckle is fixed on the rear wheel system assembly, and the rear wheel steering system assembly is provided with a steering drive shaft, and the linear stepping motor transmits the torque to the rear wheel steering after amplifying the torque through the torque amplification device assembly. On the steering drive shaft of the system assembly, the rear wheel steering system assembly is then transmitted to the steering knuckle.

In the prior art, the rear wheel steering system assembly of an electric vehicle independently driven by an in-wheel motor includes a steering transmission shaft, a rack-and-pinion steering mechanism fixedly connected to the steering transmission shaft, and a steering ball joint connected to the rack and pinion. The steering tie rod connected to the type steering mechanism, and the steering tie rod is connected with the steering trapezoidal arm of the steering knuckle to act on the wheel system assembly. However, in the prior art, the linear stepping motor is directly used to drive the rear wheel steering system assembly. The difference between the utility model and the prior art is that a torque amplification device assembly is added as the linear stepping motor and the rear wheel steering system. The connection between the assemblies converts the linear motion of the linear stepper motor into the rotational motion of the steering transmission shaft on the rear wheel steering system assembly, and the torque amplification device assembly increases the force arm through the steering mechanism connecting rod on it. The torque is amplified, and finally acts on the steering knuckle to drive the wheels to turn.

Further, in the present utility model, the torque amplifying device assembly includes a motor connecting rod, an intermediate connecting piece and a steering mechanism connecting rod, one end of the steering system connecting rod is connected with a universal joint, and the intermediate connecting piece is set on the steering A guide rail slider mechanism is formed on the system connecting rod, a motor connecting sleeve is fixed at one end of the motor connecting rod, and the other end of the motor connecting rod is fixedly connected to the intermediate connecting piece.

Further, in the present utility model, a rear wheel rotation angle sensor is provided on the steering transmission shaft. The electric vehicle independently driven by the hub motor has hub motors on the four wheels of the body to achieve independent drive; and the existing general vehicles will be equipped with steering wheel steering sensors to detect the steering wheel, that is, the angle of the front wheels. When the car is turning, the rear wheel angle will be excessive and easy to roll over. Now a new rear wheel angle sensor is added to detect the rear wheel angle, which can feed back the rear wheel angle to the control system in real time and then adjust the rear wheel through the control system. The rotation speed of the hub motor then adjusts the rear wheel angle to assist steering.

Further, in the present utility model, the motor connecting sleeve and the motor connecting rod are fixed by pins. Connect the motor connecting rod with the linear stepping motor through the motor connecting sleeve.

Further, in the present utility model, the motor connecting rod and the intermediate connecting piece are hinged through connecting pins. The connecting rod of the motor is integrated with the intermediate connecting piece, and there is no relative movement between the two.

Further, in the present utility model, the other end of the connecting rod of the steering system is provided with a nut retaining ring. Steering link follow prevents the steering link from falling off the intermediate link during movement.

Further, in the present utility model, a bracket is provided below the universal joint, a clamping device is provided on the bracket, a steering transmission shaft is provided on the rear wheel steering system assembly, and a clamping device is provided on the clamping device. There is a clamping hole matched with the steering transmission shaft, and the steering transmission shaft is connected to the universal joint through the clamping device. The clamping device can be tightened so that the contact surface between the clamping hole and the steering transmission shaft is larger, so that sliding is not easy to occur, and the connection to the steering transmission shaft is firm and reliable.

A control system of a rear wheel active steering device, comprising an electronic control unit and multiple sets of sensors connected to it, the multiple sets of sensors include a steering wheel steering angle sensor, a front wheel speed sensor, a vehicle speed sensor, a yaw angle sensor, a lateral Acceleration sensors, rear wheel angle sensors, these sensors transmit the detected vehicle motion parameters to the electronic control unit; the electronic control unit calculates the linear stepper motor control value based on the received vehicle motion parameters and transmits it to the linear stepper motor, The linear stepping motor then moves and gradually drives the torque amplification device assembly and the rear wheel steering system assembly, and finally acts on the rear wheel system assembly through the steering knuckle to realize synchronous steering control of the front and rear wheels, adjustment of the steering torque of the rear wheels and Steering is assisted by changing the speed of the hub motors on the rear wheels.

The control system records and transmits the vehicle motion parameters to the electronic control unit through the sensor, and the electronic control unit synthesizes various vehicle motion parameters, on the one hand, calculates the steering torque that the rear wheels need to achieve, and then drives the linear stepper motor to provide sufficient power to the rear wheels. Steering torque, the other party calculates the difference in the corners of the front and rear wheels, drives the in-wheel motors on the rear wheel wheel system assembly to change the corners, keeps the rear wheels in sync with the front wheels, and prevents the rear wheels from over-steering and causing the body to become unstable. This control system focuses on the description of the design idea, and the specific software and hardware involved in the realization of the above control system are all existing technologies, and those skilled in the art are capable of reproducing this control system, so I won’t go into details here.

Beneficial effect:

The utility model is suitable for electric vehicles independently driven by hub motors, and has two innovations: one is that a torque amplification device assembly is added between the linear stepper motor and the rear wheel steering system assembly, and the torque amplification device assembly is The hardware structure design of the utility model is the biggest innovation point of the utility model; the other is that the control of the rear wheel angle can be realized through the detection feedback of the sensor;

The torque amplification device assembly converts the linear motion of the linear stepper motor into the rotation of the steering transmission shaft on the rear wheel steering system assembly, and finally acts on the steering knuckle to drive the rear wheel to rotate. The stepper motor drives the rear wheel steering system assembly, and the torque amplification device assembly can provide greater steering torque for the steering of the rear wheels, which is suitable for some occasions where steering is difficult;

In addition, the movement parameters during the movement of the car are obtained through multiple sensors, especially the angle of the front and rear wheels during the steering process of the car, and this information can be fed back to the control system of the car. , calculate the angle of rotation of the front and rear wheels, and actively adjust the different speeds of the two hub motors of the rear wheels, thereby changing the angle of rotation of the rear wheels to assist steering;

The realization of the above functions also depends on the control system. The formation of the control system is inseparable from the sensor. The control system is the aid of the hardware structure to complete the complete function. The sensor is used as a detection device for motion parameters, and cooperates with the electronic control unit to form feedback. Automatically adjust the torque and angle of the rear wheels of the car according to the driving conditions of the car, so that the dynamic performance and safety of the car are guaranteed during driving.

Description of drawings

Fig. 1 is the general structural diagram of the utility model;

Fig. 2 is the structural representation of the steering torque amplification device in the utility model;

Fig. 3 is a schematic diagram of a rear wheel active steering control system.

In the figure are: front wheel steering mechanism 1, front wheel 2, front wheel hub motor 3, wheel speed sensor 4, steering wheel steering angle sensor 5, steering wheel 6, vehicle speed sensor 7, yaw rate sensor 8, lateral acceleration sensor 9, Linear stepper motor 10, electronic control unit 11, rear wheel 12, rear wheel hub motor 13, torque amplification device assembly 20, motor connecting sleeve 21, motor connecting rod 22, connecting pin 23, nut retaining ring 24, intermediate connector 25. Steering system connecting rod 26, universal joint 27, rear wheel steering system assembly 30, rear wheel angle sensor 31, steering drive shaft 32, steering mechanism 33, steering tie rod 34, steering knuckle 40, rear wheel wheel system assembly 50, hub motor 51, hub 52, tire 53.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described further.

As shown in Figure 1, it is a rear wheel active steering device, including a linear stepper motor 10, a torque amplification device assembly 20, a rear wheel steering system assembly 30, a steering knuckle 40 and a rear wheel wheel system assembly 50;

The rear wheel wheel system assembly 50 includes a tire 53, a hub 52 and a hub motor 51, the hub motor 51 is installed at the center of the hub 52 for driving the wheels to rotate, and can be respectively located on the two rear wheels through active adjustment The rotating speeds of the two wheel hub motors 51 make the outer wheel speed higher than the inner wheel speed when turning. The steering knuckle 40 is set on the motor shaft of the wheel hub motor 51 through a key connection, and is one of the important parts when the automobile turns. The kingpin rotates to turn the car. It has high strength and can make the car run stably and transmit the driving direction sensitively.

The rear wheel steering system assembly 30 includes a steering transmission shaft 32 , a steering mechanism 33 and a steering tie rod 34 . The steering mechanism 33 is a rack and pinion structure, the steering transmission shaft 32 drives the gear on the steering mechanism 33 to rotate and then drives the rack to move, the rack is connected to one end of the steering rod 34 through the steering ball head, and the other end of the steering rod 34 is connected The steering trapezoidal arms of the steering knuckle 40 are connected, and the steering rod 34 pulls the steering knuckle 40 to drive the rear wheel wheel system assembly 50 to rotate.

The linear stepper motor 10 is an important part needed when turning, and is the power source of the torque required for wheel rotation. The utility model increases the torque amplifying device assembly 20 between the linear stepping motor 10 and the rear wheel steering system assembly 30, amplifies the torque and transmits it to the rear wheel steering system assembly 30 to provide greater torque , to meet the needs of muddy roads and other situations that require large moments.

As shown in Figure 2, the torque amplification device assembly 20 includes a motor connecting rod 22, a steering system connecting rod 26 and an intermediate connecting piece 25. One end of the steering system connecting rod 26 is connected with a universal joint 27, and the other end is provided with a There is a nut retaining ring 24, and the intermediate connector 25 is sleeved on the steering system connecting rod 26 to form a guide rail slider mechanism. The nut retaining ring 24 can prevent the steering system connecting rod 26 from slipping from the intermediate connecting member 25 during the movement process. One end of the motor connecting rod 22 is fixed with a motor connecting sleeve 21 for connecting the motor connecting rod 22 to the motor shaft of the linear stepping motor through a pin, and the other end of the motor connecting rod 22 is fixedly connected to the intermediate connector 25 through a connecting pin 23 .

The motor connecting sleeve 21 transmits the linear motion of the linear stepper motor 10 to the motor connecting rod 22, and the steering system connecting rod 26 is pulled to rotate around the intermediate connecting member 25 through the intermediate connecting member 25. Since the steering mechanism connecting rod 26 is fixed to the universal joint 27 connected, and the universal joint 27 is fixedly connected with the steering transmission shaft 32, so the rotation of the universal joint 27 drives the steering transmission shaft 32 in the rear wheel steering system assembly 30 to rotate.

As shown in FIG. 3 , it is a schematic diagram of a rear wheel active steering control system.

Figure 3 schematically shows the control part of an electric vehicle independently driven by in-wheel motors. Wherein front wheel 2 is provided with wheel speed sensor 4, front wheel hub motor 3, also has front wheel steering mechanism 1 between front wheels 2, and this front wheel steering mechanism 1 links to each other directly with steering wheel 6, and through steering wheel steering angle sensor 5 Can detect front wheel 2 corners; The control part on the car rear wheel 12 is as shown in Fig. It is used to detect relevant parameters in the driving process. Various sensors and the linear stepping motor 10 are interconnected with the electronic control system 11 , the sensors transmit the detected information to the electronic control system 11 , and the electronic control system 11 controls the movement of the linear stepping motor 10 according to the feedback from the sensors.

In this control system, when the car is steering, the steering wheel angle sensor 5 and the wheel speed sensor 4 transmit the steering information of the front wheels 2 to the electronic control unit 11. At the same time, the vehicle speed sensor 7, the yaw rate sensor 8 and the lateral acceleration sensor 9 also The monitored vehicle movement parameters are transmitted to the electronic control unit 11. In addition, the rear wheel angle sensor 31 also transmits the angle information of the rear wheel 12 to the electronic control unit 11; the electronic control unit 11 analyzes the information of all sensors The calculation realizes the control of the vehicle body.

Specifically, when the vehicle is turning at a small angle, the electronic control unit 11 monitors the vehicle condition in real time, and calculates the difference between the steering angle measured by the steering wheel angle sensor 5 (i.e. the steering angle of the front wheels 2) and the actual steering angle of the rear wheels 12 value, the traction torque amplifying device assembly 20 drives the rear wheel steering system assembly 30 and then drives the rear wheels 12 to realize small-angle steering, realizing synchronous steering of the front and rear wheels;

When the car needs a large steering torque, the electronic control unit 11 can calculate the required steering torque according to the feedback from each sensor, and then drive the linear stepper motor 10 to amplify the torque through the torque amplification device assembly 20 and then transmit it to the rear wheels The system assembly 50 meets the requirement of large steering torque.

In addition, when the vehicle needs to steer at a large angle, it cannot be realized only by the active steering device of the rear wheels. At this time, the electronic control unit 11 directly adjusts the rotation speed of the two rear wheel hub motors 13 according to the feedback from the sensor, and performs the differential speed of the rear wheels to assist the steering. , and then ensure that the rear wheel active steering device can meet the needs of vehicle steering as much as possible.

The above is only a preferred embodiment of the utility model, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made. Retouching should also be regarded as the scope of protection of the present utility model.

Claims (8)

1. A rear wheel active steering device is used for an electric vehicle independently driven by a wheel hub motor, and is characterized in that: it comprises a linear stepper motor (10), a torque amplification device assembly (20), a rear wheel steering system assembly ( 30), steering knuckle (40) and rear wheel wheel system assembly (50); The steering knuckle (40) is fixed on the rear wheel wheel system assembly (50), the rear wheel steering system assembly (30) is provided with a steering transmission shaft (32), and the linear stepping motor (10) The torque is amplified by the torque amplification device assembly (20) and transmitted to the steering transmission shaft (32) of the rear wheel steering system assembly (30), and the rear wheel steering system assembly (30) is then transmitted to the steering knuckle (40) superior. 2. The rear wheel active steering device according to claim 1, characterized in that: the torque amplification device assembly (20) includes a motor connecting rod (22), a steering system connecting rod (26) and an intermediate connecting piece (25 ), one end of the steering system connecting rod (26) is connected with a universal joint (27), and the intermediate connector (25) is sleeved on the steering system connecting rod (26) to form a guide rail slider mechanism, and the motor connecting rod ( 22) One end is fixed with a motor connecting sleeve (21), and the other end of the motor connecting rod (22) is fixedly connected on the intermediate connector (25). 3. The rear wheel active steering device according to claim 1, characterized in that: the steering transmission shaft (32) is provided with a rear wheel angle sensor (31). 4. The rear wheel active steering device according to claim 2, characterized in that: the motor connecting sleeve (21) and the motor connecting rod (22) are fixed by pins. 5. The rear wheel active steering device according to claim 2, characterized in that: the motor connecting rod (22) is hinged to the intermediate connecting piece (25) through a connecting pin (23). 6. The rear wheel active steering device according to claim 2, characterized in that: the other end of the steering system connecting rod (26) is provided with a nut retaining ring (24). 7. The rear wheel active steering device according to claim 2, characterized in that: a support (28) is provided below the universal joint (27), and a clamping device is provided on the support (28), clamping The clamping device is provided with a clamping hole matched with the steering transmission shaft (32), and the steering transmission shaft (32) is connected to the universal joint (27) through the clamping device. 8. A control system for a rear wheel active steering device, characterized in that it comprises an electronic control unit (11) and multiple groups of sensors connected thereto, wherein the multiple groups of sensors include a steering wheel steering angle sensor (5), a front wheel speed Sensor (4), vehicle speed sensor (7), yaw angle sensor (8), lateral acceleration sensor (9), rear wheel angle sensor (31), these sensors transmit the detected vehicle motion parameters to the electronic control unit; The electronic control unit (11) calculates the control value of the linear stepping motor according to the received vehicle motion parameters and transmits it to the linear stepping motor (10), and the linear stepping motor (10) then moves and gradually drives the torque amplification device assembly (20), the rear wheel steering system assembly (30), finally acts on the rear wheel wheel system assembly (50) through the steering knuckle (40), to realize the synchronous steering of the front and rear wheels, adjust the steering torque of the rear wheels and change the The hub motors on the wheels spin to assist the steering.