Five-connecting-rod rear suspension system and control method thereof

Abstract

The invention relates to the technical field of vehicle suspension systems, in particular to a five-connecting-rod rear suspension system and a control method thereof. Comprising a connecting rod suspension mechanism, a motor, a torque push rod, a shock absorber and a spring. The five-connecting-rod suspension mechanism is used for connecting wheels and a vehicle body. The motor serves as a hub motor and is integrated at a hub of the wheel; the upper end of the torque push rod is connected with a vehicle body through a swivel bearing, and the lower end is connected with the rotor output end of the motor through a knuckle bearing. The shock absorber and the spring are arranged on the rear portion of a tire and connected between a vehicle body and the five-connecting-rod suspension mechanism. The invention aims to overcome the technical defect that an existing five-connecting-rod suspension system is lack of integrated hub motor driving and active suspension functions.

Description

Technical Field

[0001] This invention relates to the field of vehicle suspension system technology, and in particular to a five-link rear suspension system and its control method. Background Technology

[0002] A five-link suspension is a suspension structure consisting of two upper arms, two lower arms, and one toe arm. It effectively resists longitudinal, lateral, and vertical forces on the wheels, ensuring wheel stability and ride comfort. The advantages of a five-link suspension include: flexible structure, allowing adjustment of the size and shape of each link to achieve optimal suspension geometry and dynamics according to different vehicle models and operating conditions; good handling performance, enabling rear-wheel steering or adaptive steering, improving vehicle steering response and handling stability; and good comfort performance, effectively isolating road impacts and noise, improving ride comfort and quietness.

[0003] However, existing five-link suspension systems have the following technical shortcomings: First, traditional five-link suspension layouts often cannot simultaneously meet the design requirements of a low and flat rear floor, especially in applications such as electric logistics vehicles and MPVs, where the suspension structure occupies excessive space. Second, current technology lacks a solution for effectively integrating in-wheel motor drive and active suspension functions. Finally, existing suspension systems generally lack active damping control capabilities, failing to adjust suspension characteristics in real time according to vehicle driving conditions, thus limiting the vehicle's overall performance under different operating conditions. Summary of the Invention

[0004] The purpose of this invention is to address the technical deficiency of existing five-link suspension systems that lack integrated hub motor drive and active suspension functions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: According to a first aspect of the present invention, a five-link rear suspension system is provided, comprising: a five-link suspension mechanism, a motor, a torque push rod, a shock absorber, and a spring; the five-link suspension mechanism is used to connect a wheel to a vehicle body; the motor is integrated as a hub motor at the wheel hub; the upper end of the torque push rod is connected to the vehicle body via a rotary bearing, and the lower end is connected to the rotor output end of the motor via a spherical bearing; the shock absorber and the spring are disposed at the rear of the tire and connected between the vehicle body and the five-link suspension mechanism; wherein the motor is configured to drive the torque push rod to generate a controlled extension force along its axial direction by controlling the output torque of its rotor, the force ultimately acting on the shock absorber to achieve an active suspension function.

[0006] Optionally, the five-link suspension mechanism includes two upper arms, two lower arms, and one toe arm.

[0007] Optionally, the two upper arms and two lower arms include a pair of parallel upper and lower cross arms, which are configured to keep the angle of the torque push rod in the vertical direction constant during wheel bounce.

[0008] Optionally, the two upper arms and two lower arms include a pair of upper and lower longitudinal arms, which are arranged to cooperate in maintaining the angle of the torque push rod in the vertical direction during wheel bounce.

[0009] Optionally, the rotary bearing is configured to allow the torque push rod to rotate about its own axis; the spherical bearing is a ball joint structure.

[0010] Alternatively, the motor may be a dual-stator single-rotor axial flux motor.

[0011] Optionally, the rotor output end of the dual-stator single-rotor axial flux motor is provided with a motor torque push rod, and the lower end of the torque push rod is connected to the motor torque push rod through the spherical bearing.

[0012] According to a second aspect of the present invention, a method for controlling the aforementioned five-link rear suspension system is provided, characterized by comprising the following steps: acquiring a vehicle state signal; calculating a target rotor torque to be output by the motor based on the vehicle state signal and the real-time geometric attitude of the torque push rod; controlling the motor to output the target rotor torque; the target rotor torque being converted into an axial driving force on the torque push rod through its output end, the axial driving force being used to adjust the load borne by the shock absorber, thereby actively controlling the vehicle body attitude.

[0013] Optionally, the vehicle status signal may include one or more of the following: vehicle vertical acceleration, vehicle lateral acceleration, wheel hop displacement, and steering angle.

[0014] Optionally, the vertical angle of the torque push rod remains unchanged during wheel bounce. The advantages of this invention are as follows: By integrating a hub motor and a torque push rod, an active suspension function is achieved, which can actively control the changes in suspension damping force, resulting in better handling performance and comfort compared to existing passive suspension systems; the design of placing the shock absorber at the rear of the tire reduces the height of the shock absorber pivot point, meeting the design requirements of a low and flat rear floor, which is particularly suitable for the space requirements of electric logistics vehicles and MPV models; the parallel arrangement of the upper and lower cross arms and the optimized arrangement of the upper and lower longitudinal arms ensure the stability and accuracy of the vertical force control of the torque push rod, resulting in better kinematic characteristics compared to traditional five-link suspensions. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the five-link rear suspension system described in this invention; Figure 2 This is a flowchart of the control method described in this invention.

[0017] In the diagram: 1. Torque push rod; 2. Shock absorber; 3. Spring; 4. Motor; 5. Upper cross arm; 6. Lower cross arm; 7. Upper longitudinal arm; 8. Lower longitudinal arm; 9. Toe arm. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 like Figure 1 As shown, this embodiment provides a five-link rear suspension system specifically designed for vehicles requiring a low and flat rear floor, such as logistics vehicles or MPVs. This system combines a five-link suspension mechanism with in-wheel motor 4-wheel drive technology to achieve active suspension functionality.

[0020] The five-link rear suspension system consists of five main components: a five-link suspension mechanism, a motor 4, a torque push rod, a shock absorber 2, and a spring 3.

[0021] The five-link suspension mechanism, as the core structure connecting the wheels and the vehicle body, includes two upper arms, two lower arms, and one toe arm 9. The two upper arms and two lower arms include a pair of parallel upper lateral arms 5 and lower lateral arms 6. This parallel arrangement ensures that the torque pushrod angle remains constant in the vertical direction during wheel bounce, facilitating precise control of the torque pushrod's vertical force. Simultaneously, the two upper arms and two lower arms also include a pair of upper longitudinal arms 7 and lower longitudinal arms 8. The special arrangement of the upper longitudinal arms 7 and lower longitudinal arms 8 also helps to collaboratively maintain the torque pushrod angle in the vertical direction during wheel bounce, further improving the system's stability and control precision.

[0022] Motor 4 adopts a dual-stator single-rotor axial flux motor structure and is integrated into the wheel hub as a hub motor 4. This axial flux motor 4 can provide multi-directional torque function, providing the necessary power support for the active suspension system. The rotor output end of the dual-stator single-rotor axial flux motor 4 is equipped with a motor 4 torque push rod, which serves as the transmission mechanism for the output torque of motor 4.

[0023] The torque pushrod, a key component connecting motor 4 to the suspension system, is connected to the vehicle body at its upper end via a rotary bearing and to the rotor output end of motor 4 at its lower end via a spherical bearing. The rotary bearing allows the torque pushrod to rotate around its own axis, ensuring smooth system movement as the tire bounces up and down. The spherical bearing uses a ball joint structure, connecting the lower end of the torque pushrod to the torque pushrod of motor 4, ensuring effective torque transmission.

[0024] Shock absorber 2 and spring 3 are located at the rear of the tire and connected between the vehicle body and the five-link suspension mechanism. This placement of the shock absorber 2 and spring 3 at the rear of the tire serves two important purposes: firstly, it avoids spatial overlap with the torque pushrod, and secondly, it does not occupy the lateral space of the steering module. This arrangement also allows for a lower pivot point for shock absorber 2, while maintaining a suitable distance between the shock absorber 2 and the passenger to minimize noise.

[0025] The five-link rear suspension system operates based on active suspension technology. Motor 4 controls the output torque of its rotor to drive a torque pushrod along its axial direction, generating a controlled extension / retraction force. This force ultimately acts on the shock absorber 2, thus achieving the active suspension function. The system controls the force of the torque pushrod in the axial flux motor 4 to control the changes in suspension damping force, thereby achieving the function of active suspension.

[0026] During vehicle operation, when the wheels encounter uneven road surfaces, the five-link suspension mechanism is the first to sense the impact and begin to move. Due to the parallel arrangement of the upper and lower lateral arms and the coordinated action of the upper and lower longitudinal arms, the torque pushrod maintains a relatively constant vertical angle throughout the wheel's movement. At this time, the dual-stator single-rotor axial flux motor 4 precisely controls its output torque according to road conditions and vehicle requirements, transmitting the torque to the torque pushrod via the motor 4 torque pushrod. The torque pushrod converts this torque into a controlled axial extension force, which ultimately acts on the shock absorber 2, achieving active adjustment of the suspension damping characteristics.

[0027] This design allows the suspension system to not only passively absorb road impacts but also actively adjust damping characteristics, providing optimal suspension performance according to different driving conditions. Simultaneously, since the rear suspension does not require steering, the torque pushrod's upper pivot point is connected to the vehicle body via a bearing, retaining only rotational functionality, simplifying the structure while improving reliability. The integrated design of the entire system is particularly suitable for hub-motor 4WD vehicles requiring a low rear floor and integrated active suspension.

[0028] Example 2 like Figure 2 As shown, this embodiment provides a method for controlling a five-link rear suspension system. This method is based on the five-link rear suspension system described in Embodiment 1 and achieves precise control of the vehicle body posture by actively adjusting the output torque of the motor.

[0029] The control method includes the following steps: Step 1: Acquiring Vehicle Status Signals. The system collects vehicle operating status information in real time through various sensors. Vehicle status signals include one or more of the following: vertical acceleration, lateral acceleration, wheel hop displacement, and steering angle. Vertical acceleration reflects the vehicle's motion in the vertical direction; lateral acceleration reflects the acceleration change during turning or lateral movement; wheel hop displacement represents the vertical displacement of the wheels relative to the vehicle body; and steering angle reflects the vehicle's steering state. These signals provide the necessary basic data for subsequent control calculations.

[0030] Step Two: Based on the vehicle status signal and the real-time geometric attitude of the torque push rod, calculate the target rotor torque that the motor needs to output. The control system, based on the vehicle status signal obtained in Step One and combined with the current real-time geometric attitude information of the torque push rod, calculates the target torque value that the motor rotor should output using a preset control algorithm. During the calculation process, the vertical angle of the torque push rod remains unchanged during wheel movement; this characteristic simplifies the complexity of the control algorithm and improves control accuracy. The system comprehensively considers the vehicle's current motion state, road conditions, and driving needs to determine the optimal rotor target torque to achieve the ideal suspension control effect.

[0031] Step 3: Control the motor output rotor target torque. The control system sends control commands to the dual-stator single-rotor axial flux motor, causing the motor to accurately output the rotor target torque calculated in Step 2. The motor responds to the control commands by adjusting its internal electromagnetic field distribution and current magnitude to achieve precise control of the rotor output torque.

[0032] Step Four: The rotor's target torque is converted into an axial driving force on the torque pushrod via its output end, adjusting the load on the shock absorber and thus actively controlling the vehicle's attitude. The rotor's target torque output by the motor is transmitted to the torque pushrod via the motor torque pushrod, which converts the received torque into an axial driving force. Since the upper end of the torque pushrod is connected to the vehicle body via a rotary bearing, and the lower end is connected to the motor rotor's output end via a spherical bearing, this connection method ensures effective torque transmission and conversion. The axial driving force ultimately acts on the shock absorber located at the rear of the tire, changing the load distribution and magnitude on the shock absorber. In this way, the system can actively adjust the suspension's damping characteristics according to actual needs, achieving precise control of the vehicle's attitude and improving vehicle handling performance and ride comfort.

[0033] The entire control process forms a closed-loop control system. By continuously acquiring vehicle status signals, calculating target torque, controlling motor output, and adjusting suspension load, it achieves real-time active control of vehicle posture, effectively coping with various road conditions and driving situations.

[0034] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A five-link rear suspension system, characterized in that, include: Five-link suspension mechanism, motor, torque push rod, shock absorber and spring; The five-link suspension mechanism is used to connect the wheels and the vehicle body; The motor is integrated as a hub motor at the hub of the wheel; The upper end of the torque push rod is connected to the vehicle body via a rotary bearing, and the lower end is connected to the rotor output end of the motor via a spherical bearing. The shock absorber and the spring are located at the rear of the tire and connected between the vehicle body and the five-link suspension mechanism; The motor is configured to drive the torque push rod to generate a controlled telescopic force along its axial direction by controlling the output torque of its rotor. This force ultimately acts on the shock absorber to achieve the active suspension function.

2. The five-link rear suspension system according to claim 1, characterized in that: The five-link suspension mechanism includes two upper arms, two lower arms, and one toe arm.

3. The five-link rear suspension system according to claim 2, characterized in that: The two upper arms and two lower arms include a pair of parallel upper and lower cross arms, which are configured to keep the angle of the torque push rod in the vertical direction unchanged during wheel bounce.

4. The five-link rear suspension system according to claim 2, characterized in that: The two upper arms and two lower arms include a pair of upper and lower longitudinal arms, which are arranged to cooperate in maintaining the angle of the torque push rod in the vertical direction during wheel bounce.

5. The five-link rear suspension system according to claim 1, characterized in that: The rotary bearing is configured to allow the torque push rod to rotate about its own axis; the spherical bearing is a ball joint structure.

6. The five-link rear suspension system according to claim 1, characterized in that: The motor is a dual-stator single-rotor axial flux motor.

7. The five-link rear suspension system according to claim 6, characterized in that: The rotor output end of the dual-stator single-rotor axial flux motor is provided with a motor torque push rod, and the lower end of the torque push rod is connected to the motor torque push rod through the spherical bearing.

8. A method for controlling a five-link rear suspension system as described in any one of claims 1-7, characterized in that, Includes the following steps: Acquire vehicle status signals; Based on the vehicle status signal and the real-time geometric attitude of the torque push rod, the target rotor torque that the motor needs to output is calculated; Control the motor to output the target torque of the rotor; The target torque of the rotor is converted into an axial driving force on the torque push rod through its output end. This axial driving force is transmitted to adjust the load on the shock absorber, thereby actively controlling the vehicle body posture.

9. The method according to claim 8, characterized in that: The vehicle status signals include one or more of the following: vertical acceleration of the vehicle body, lateral acceleration of the vehicle body, wheel hop displacement, and steering angle.

10. The method according to claim 8, characterized in that: The vertical angle of the torque push rod remains unchanged during wheel bounce.

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