A large turning angle double wishbone suspension integrated steer-by-wire system

Abstract

The application relates to a large-angle double-long-arm suspension integrated steer-by-wire system, which comprises a steering motor, a speed reducer, a wheel steering rotating pair and wheels which are sequentially connected in transmission from top to bottom, and the wheel steering rotating pair is connected with a vehicle body through upper and lower longitudinal arms. Compared with the prior art, the application has the advantages of meeting the high-speed rotation of the steering motor under the condition of large speed reduction ratio, high space utilization, small vertical space occupation, effectively limiting the axial movement of the steering knuckle relative to the shaft sleeve, realizing the wheel steering of + / -90 DEG and light weight, etc.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric vehicle chassis and steering, in particular to a large-angle double wishbone suspension integrated steer-by-wire system. BACKGROUND

[0002] At present, independent steering and driving integrated modules are divided into three types according to different suspension arrangement modes, namely, the wishbone type, the wishbone type and the upright type.

[0003] The wishbone type independent steering and driving integrated module structure is mainly developed based on the McPherson suspension and double wishbone suspension, which is similar to the traditional vehicle suspension structure, has good adaptability with traditional chassis, steering knuckle and other components, and the technology is relatively mature. However, due to the existence of the swing arm and the limitation of the transmission mode, the range of the steering angle generally cannot reach ±90°, and in addition, the kingpin offset distance of the wishbone type integrated module is large due to the fact that the hub motor has occupied most of the wheel space.

[0004] The wishbone type independent steering and driving integrated module is currently applied to the development case of the wheel drive system, mainly considering integrating the transmission mechanism in the wishbone, which solves the problem of power transmission of the wheel drive motor and improves the integration of the wheel drive system, but generally does not have steering function.

[0005] The main feature of the upright type independent steering and driving integrated module is that the steering motor is arranged above the wheel, and the output shaft line of the steering motor (or reducer) is the kingpin of the wheel. The main difference lies in the arrangement position and form of the spring shock absorber assembly and the form of the reduction mechanism. This type of configuration has the advantages of compact structure, high integration, small kingpin offset distance, even zero, can realize ±90° steering of the wheel, and requires less wheel space, but occupies more vertical space. In addition, the module is connected to the frame only through the top bolt, and the connection will bear a large bending moment. SUMMARY

[0006] The purpose of the present application is to overcome the defects of the prior art and provide a large-angle double wishbone suspension integrated steer-by-wire system.

[0007] The purpose of the present application can be achieved by the following technical solutions:

[0008] A large-angle double wishbone suspension integrated steer-by-wire system, the system comprises a steering motor, a reducer, a wheel steering rotating pair and a wheel which are sequentially connected in transmission from top to bottom, the wheel steering rotating pair is connected with the vehicle body through an upper wishbone and a lower wishbone respectively.

[0009] The wheel steering rotation pair comprises a cross shaft universal joint, a bearing / axle assembly, a transmission shaft and a steering knuckle, the upper end of the cross shaft universal joint is in transmission connection with the output end of the speed reducer, the lower end is in transmission connection with the upper end of the transmission shaft, and the lower end of the transmission shaft is in fixed connection with the steering knuckle for driving the wheel steering after passing through the bearing / axle assembly.

[0010] The bearing / axle assembly is composed of a sleeve and angular contact bearings arranged at the upper and lower ends of the sleeve respectively for supporting the transmission shaft, and the transmission shaft is in fixed connection with the steering knuckle after sequentially passing through the inner rings of the two angular contact bearings.

[0011] The upper end of the upper longitudinal arm is in rotation connection with the sleeve through a pair of ball hinges, and the other end is in rotation connection with the vehicle body through an elastic rubber bushing.

[0012] The middle part of the upper longitudinal arm is in rotatable connection with the speed reducer through a pair of connecting rods, the upper end of the connecting rod is connected with the speed reducer through an upper joint bearing, and the lower end is connected with the middle part of the upper longitudinal arm through a lower joint bearing.

[0013] The lower end of the lower longitudinal arm is in rotation connection with the lower end of the circular arc connecting rod through a second rotation pair, the other end is in rotation connection with the vehicle body through an elastic rubber bushing, and the upper end of the circular arc connecting rod is in fixed connection with the sleeve.

[0014] The middle part of the lower longitudinal arm is in rotation connection with the lower end of the spring-damping shock absorber through a first rotation pair, and the upper end of the spring-damping shock absorber is hinged to the vehicle body.

[0015] The speed reducer adopts a worm gear reducer.

[0016] The output shaft line of the speed reducer and the axis line of the wheel steering rotation pair both pass through the center of the cross shaft universal joint.

[0017] The specific transmission process of the steering system for wheel steering is as follows:

[0018] The output torque of the steering motor is transmitted to the transmission shaft through the cross shaft universal joint fixedly connected with the output shaft of the speed reducer after being amplified by the speed reducer, and the transmission shaft outputs the steering torque to the steering knuckle, so that the wheel can rotate around the axis line of the wheel steering rotation pair, i.e. the steering kingpin axis line of the steering system, thereby realizing the function of the linear control four-wheel independent steering.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] 1. The present application closely combines the current front development direction of the "sliding plate type linear control chassis", and proposes an innovative linear control independent steering / driving / suspension integrated chassis angle module design scheme.

[0021] 2. The steering motor is connected with the worm and gear reducer, the reversing function is formed through the worm and gear reducer, the output torque is transmitted to the transmission shaft through the universal joint, the knuckle connected with the transmission shaft and the wheel connected with the knuckle are driven to steer, and the transmission form of the worm and gear reducer can meet the high-speed rotation of the steering motor under the condition of large reduction ratio.

[0022] 3. The longitudinal arm suspension and the integrated module of the steer-by-wire are combined, the utilization rate of the chassis transverse space is high, the suspension swing arm configuration design of the circular arc connecting rod and the design of the spring damper and the lower longitudinal arm are adopted, and the vertical space occupation is smaller than that of the upright independent steering and driving integrated module.

[0023] 4. The axis of the rotating pair between the transmission shaft and the shaft sleeve passes through the center of the cross universal joint, and the axis is the kingpin axis of the system.

[0024] 5. The transmission shaft is nested in the shaft sleeve, the angular contact bearing (which can simultaneously bear axial force and radial force) is installed in the shaft sleeve for supporting the transmission shaft, the knuckle and the transmission shaft cannot move axially relative to the shaft sleeve, and only rotation around the kingpin axis can occur.

[0025] 6. The kingpin offset distance is 0, ±90° wheel steering can be realized, no motion interference of the mechanism occurs in the large angle (±90°) rotation process, and the functional requirements of the steer-by-wire independent steering, independent driving and omnidirectional mobile electric vehicle are met.

[0026] 7. The worm and gear reducer is arranged at the top of the steering system and is connected with the upper longitudinal arm through four joint bearings and a pair of connecting rods, can play a supporting role, the load bearing capacity of the reducer for the reaction torque received when driving the wheels to rotate is good, at the same time, there is no need to design a subframe and the like for installing the worm and gear reducer, and the lightweight advantage is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the integrated steer-by-wire system of the application.

[0028] Figure 2 It is a structural schematic diagram of the integrated steer-by-wire system of the application in large angle steering (90°).

[0029] Figure 3 It is a mechanism principle diagram of the integrated steer-by-wire system of the application.

[0030] MARK DESCRIPTION IN THE DRAWING:

[0031] 1. Upper joint bearing; 2. Connecting rod; 3. Lower joint bearing; 4. Upper trailing arm; 5. Spring-damped shock absorber; 6. Lower trailing arm; 7. First rotating joint; 8. Second rotating joint; 9. Wheel; 10. Arc-shaped connecting rod; 11. Steering knuckle; 12. Drive shaft; 13. Ball joint; 14. Angular contact bearing; 15. Bushing; 16. Steering motor; 17. Universal joint; 18. Worm gear reducer; 19. Body. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0033] Example

[0034] To make the objectives, technical features, and technical effects of the present invention clearer, the following will describe the exemplary solutions of the present invention clearly and completely with reference to the accompanying drawings of the embodiments of the present invention.

[0035] like Figure 1 As shown, this invention provides a novel large-angle double trailing arm suspension integrated steer-by-wire system. The system includes a steering motor 16, an upper trailing arm 4, a lower trailing arm 6, and a steering knuckle 11 for steering the wheels 9. The upper trailing arm 4 and lower trailing arm 6 are respectively connected to the vehicle body 19. The steering system also includes a bearing / shaft assembly, a universal joint 17, and an arc-shaped connecting rod 10. The steering knuckle 11 is fixedly connected to the lower end of the drive shaft 12. The joint rotation drives the wheel 9 to steer. The bushing 15 is connected to the upper longitudinal arm 4 through a pair of ball joints 13. The upper end of the arc-shaped connecting rod 10 is fixed to the bushing 15, and the lower end is connected to the lower longitudinal arm 6 through the second rotating joint 8. The upper end of the spring damping shock absorber 5 is connected to the body 19, and the lower end is rotatably connected to the lower longitudinal arm 6 through the first rotating joint 7. The upper longitudinal arm 4 and the lower longitudinal arm 6 are connected to the body 19 through elastic rubber bushings. The center of the cross shaft universal joint 17 is located on the axis of the rotating joint (wheel steering rotating joint) between the drive shaft 12 and the bushing 15.

[0036] In this example, the steering motor 16 and the worm gear reducer 18 are located at the top of the steering system and are connected to the upper trailing arm 4 via two upper joint bearings 1, two connecting rods 2 and two lower joint bearings 3.

[0037] Steering motor 16 (in this case, a stepper motor) and worm gear reducer 18 are fixed to the cardan joint 17, and the output shaft of the cardan joint 17 transmits torque to the transmission shaft 12, drives the steering knuckle 11 connected to the transmission shaft 12 and the wheel 9 connected to the steering knuckle 11 to rotate around the wheel steering rotation axis. To achieve this, the output axis of the worm gear reducer 18 and the axis of the wheel steering rotation pair must pass through the center of the cardan joint 17. The axis of the rotation pair between the transmission shaft 12 and the sleeve 15, i.e. the steering kingpin axis of the system, and the sleeve 15 are connected by an angular contact bearing 14 to support the transmission shaft 12, which cannot move axially relative to the sleeve 15 but can only rotate around the steering kingpin axis. The sleeve 15 is connected to the upper wishbone 4 by a spherical hinge 13, and the movement pairs between the upper wishbone 4 and the lower wishbone 6 and the vehicle body 19 are all rotation pairs, which can be realized by elastic rubber bushings.

[0038] The specific transmission process of wheel steering is as follows:

[0039] The steering motor 16 outputs torque, which is amplified by the worm gear reducer 18 and then transmitted to the transmission shaft 12 through the cardan joint 17 fixed to the output shaft of the worm gear reducer 18. The transmission shaft 12 then outputs steering torque to the steering knuckle 11, allowing the wheel 9 to rotate around the steering kingpin axis, thereby realizing the steer-by-wire four-wheel independent steering function.

[0040] The structural diagram of this structural scheme when steering at a large angle (90°) is shown in Figure 2 During wheel rotation or wheel jump, there is no motion interference of the mechanism, and the steering angle of the wheel in both steering directions can reach 90°, which has the advantage of a large steering angle range.

[0041] As shown in Figure 3 On the basis of the double-wishbone suspension structure, a rotation pair formed by bearing / axle assemblies and other components is added to the steering knuckle 11, and the rotation pair is controlled by the controllable steering motor 16 and the worm gear reducer 18. When not steering, the steering motor 16 does not rotate. In addition, the cardan joint 17 is not only a transmission component for transmitting steering torque, but also forms a rotation pair that allows the steering motor 16 and the worm gear reducer 18 to meet the degree of freedom requirements of the mechanism when the wheel jumps and the output shaft of the reducer is not collinear with the steering kingpin axis.

[0042] In addition, the reducer connected to the steering motor 16 is a worm gear reducer 18. When the return torque is large and the output torque of the steering motor 16 and the worm gear reducer 18 assembly cannot maintain the stability of the wheel direction, the self-locking function can be realized by using this transmission form.

Claims

1. A large-angle double trailing arm suspension integrated steer-by-wire system, characterized in that, The system includes a steering motor (16), a reducer, a wheel steering joint, and a wheel (9) connected sequentially from top to bottom. The wheel steering joint is connected to the vehicle body via an upper longitudinal arm (4) and a lower longitudinal arm (6). The wheel steering joint includes a universal joint (17), a bearing / shaft assembly, a drive shaft (12), and a steering knuckle (11). The upper end of the universal joint (17) is connected to the output end of the reducer, and the lower end is connected to the upper end of the drive shaft (12). The lower end of the drive shaft (12) is fixed to the steering knuckle (11) that drives the wheel (9) to turn after passing through the bearing / shaft assembly. The bearing / shaft assembly consists of a bushing (15). It consists of angular contact bearings (14) respectively set at the upper and lower ends of the bushing (15) to support the drive shaft (12). The drive shaft (12) passes through the inner rings of the two angular contact bearings (14) and is fixed to the steering knuckle (11). One end of the upper longitudinal arm (4) is rotatably connected to the bushing (15) through a pair of ball joints (13), and the other end is rotatably connected to the vehicle body (19) through an elastic rubber bushing. One end of the lower longitudinal arm (6) is rotatably connected to the lower end of the arc-shaped connecting rod (10) through the second rotating pair (8), and the other end is rotatably connected to the vehicle body (19) through an elastic rubber bushing. The upper end of the arc-shaped connecting rod (10) is fixed to the bushing (15).

2. The large-angle double trailing arm suspension integrated steer-by-wire system according to claim 1, characterized in that, The upper longitudinal arm (4) is rotatably connected to the reducer via a pair of connecting rods (2). The upper end of the connecting rod (2) is connected to the reducer via an upper joint bearing (1), and the lower end is connected to the middle part of the upper longitudinal arm (4) via a lower joint bearing (3).

3. The large-angle double trailing arm suspension integrated steer-by-wire system according to claim 1, characterized in that, The lower longitudinal arm (6) is rotatably connected to the lower end of the spring damper (5) through the first rotating joint (7), and the upper end of the spring damper (5) is hinged to the vehicle body (19).

4. The large-angle double trailing arm suspension integrated steer-by-wire system according to claim 1, characterized in that, The speed reducer is a worm gear reducer (18).

5. The large-angle double trailing arm suspension integrated steer-by-wire system according to claim 1, characterized in that, The output axis of the reducer and the axis of the wheel steering joint both pass through the center of the cross shaft universal joint (17).

6. The large-angle double trailing arm suspension integrated steer-by-wire system according to claim 5, characterized in that, The specific transmission process by which the steering system achieves wheel (9) steering is as follows: The steering motor (16) outputs torque, which is amplified by the reducer and then transmitted to the drive shaft (12) through the universal joint (17) fixed to the output shaft of the reducer. The drive shaft (12) then outputs the steering torque to the steering knuckle (11), so that the wheel (9) can rotate around the axis of the wheel steering pair, that is, the steering kingpin axis of the steering system, thereby realizing the steer-by-wire four-wheel independent steering function.

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