AU2010330482B2

AU2010330482B2 - Steering wheel rotation angle sensor device and electronic stability program system of automobile

Info

Publication number: AU2010330482B2
Application number: AU2010330482A
Authority: AU
Inventors: Lichen Cao; Zhiyong Gao; Wenjuan Kan; Ming Liu; Yanhong Liu; Juntao Tian; Wanshun Wang; Shuheng Ye; Jun Zhang; Junru Zhang
Original assignee: Beiqi Foton Motor Co Ltd
Current assignee: Beiqi Foton Motor Co Ltd
Priority date: 2009-12-11
Filing date: 2010-12-10
Publication date: 2013-12-05
Anticipated expiration: 2030-12-10
Also published as: AU2010330482A1; WO2011069464A1; CN101708736A; CN101708736B

Abstract

A rotation angle sensor device for a steering wheel comprises a magnetic induction sensor (2) and a rotation angle transmission component (5). A transmission structure is formed between an upper pipe section (13) of the rotation angle transmission component (5) and a clock spring mechanism (1). The inner circumference of the upper pipe section (13) is provided with a radial location mechanism (7) and a first axial location mechanism. The outer circumference of the upper pipe section (13) is provided with a second axial location mechanism. An inner bush (21) of the magnetic induction sensor (2) is provided with a third axial location mechanism. The outer circumference of the upper pipe section (13) and the inner bush (21) of the magnetic induction sensor (2) are also provided with a circumferential locking and transmission mechanism. An electronic stabilization system for an automobile comprises the rotation angle sensor device for the steering wheel connected with a central control unit via a signal line. The rotation angle sensor device for the steering wheel of the present invention adopts the magnetic induction sensor which is more reliable in work, realizes the installation and the precise location of the magnetic induction sensor within a limited space below a steering wheel, and reliably transfers the rotation of the steering wheel to the magnetic induction sensor.

Description

Steering Wheel Rotation angle Sensor Device and Electronic Stability Program System of Automobile Field of the Invention The present invention relates to a steering wheel rotation angle sensor device for electronic stability program (ESP) system of automobile, more particularly, to a steering wheel rotation angle sensor device comprising a rotation angle sensor. In addition, the present invention further relates to an ESP system that comprises the steering wheel rotation angle sensor device. Background of the Invention With the development of the automotive industry, people pay more and more attention to the stability and safety of automobile braking and steering operations. Presently, most automobiles are equipped with an anti-lock braking system (ABS). In the braking process, the ABS system functions only when a wheel tends to be locked, and is mainly a passively reactive safety system. However, due to the present situation of changing road conditions and increasingly congested traffic, such a passively reactive ABS system can't meet people's safety requirements to a great extent, and an actively reactive safety system that can act proactively is required. In this case, more and more automobiles employ an ESP system. An ESP system mainly comprises electronic control unit (ECU), actuator, steering wheel rotation angle sensor, vehicle movement speed sensor, braking force sensor, and transverse-swing angular speed sensor, etc., and it exercises active intervention, regulation, and control to the engine and braking system, on the basis of real-timely monitoring of automobile running state via the ECU. During the movement of automobile, the steering wheel rotation angle sensor senses the steering direction and steering angle intended by the driver, the vehicle movement speed sensor senses the vehicle movement speed, fuel throttle opening degree, and driving torque, etc.; the braking sensor sends the magnitude of braking force; the transverse-swing angular speed sensor detects the deflection around the vertical axis (the deflection amount represents the degree of stability of the automobile, if the deflection angular speed reaches to a threshold, it indicates the automobile is in a dangerous condition, such as sideslip or braking swerve). The ECU of ESP acquires the data and then calculates and judges the difference between normal safe running state and the driver's intention of control, and then sends orders to regulate the engine rotation speed and wheel braking force, and thereby correct over-steering or under-steering tendency, to avoid wheel skidding, over-steering, under-steering, or wheel locking to ensure safe running of the automobile. Properly speaking, the ESP system actually includes the functions of ABS and TCS (Traction Control System), but the functions are not simply combined with ABS and TCS. The main difference lies in: ABS or TCS can 1 3425551_2 (G HMatters) P90652.AU only respond passively, while ESP can actively detect and analyze automobile condition and correct driving errors, i.e., it intervenes proactively. A steering wheel rotation angle sensor is an indispensable component of ESP, The steering wheel rotation angle sensor is designed to convert the steering wheel rotation angle into a signal that represents the steering direction expected by the driver, and the ESP identifies the driver's intention by calculating the magnitude and change rate of the steering wheel rotation angle. However, most existing ESP systems employ grating sensor, wherein, the steering wheel rotation angle is usually determined by photoelectric code; a coding disk mounted on the steering shaft contains coded datum such as rotation direction, rotation angle, etc.; the data in the coding disk is scanned by a proximity type photoelectric coupler. After the ignition switch of the automobile is switched on and the steering wheel rotation angle sensor rotates by an angle, the ECU of ESP will determine the present absolute steering wheel rotation angle with a pulse sequence. A drawback of such steering wheel rotation angle sensor is that the sensor may be damaged easily. Once the steering wheel rotation angle sensor is damaged, the ECU of ESP will be unable to ascertain the driving intension of the driver (in particular the steering direction of the automobile), and thereby the entire ESP will fail. Presently, regarding the principle of signal generation, it is technically feasible to replace grating sensor with magnetic induction sensor that is more reliable. When a magnetic induction sensor is used, the internal bushing in the magnetic induction sensor is driven by the steering wheel or steering wheel shaft to cut the magnetic lines of force created by the magnet in the magnetic induction sensor, and thereby the ECU can determine the steering wheel rotation angle magnitude, rotation angle change rate, and steering direction on the basis of the pulse width, pulse amplitude, and pulse direction of the resultant current signal. However, there is some difficulty in the installation of magnetic induction sensor, though magnetic induction sensor is more reliable. The installation space below the steering wheel is very limited, and some components such as clock spring mechanism and combined switch have to be installed below the steering wheel, especially, when a magnetic induction sensor is installed, if a conventional axial positioning mechanism is used (e.g., a simple projection-groove fitting mechanism or a snap stop ring, etc.), interferences to the installation is often created, and consequently the magnetic induction sensor can't be installed; if a positioning pin is used for positioning, the installation process can't be completed successfully since the pin hole can't be aligned to the positioning pin accurately. Therefore, how to accomplish installation and accurate positioning of the magnetic induction sensor and transfer the rotation of the steering wheel to the magnetic induction sensor accurately is a tough technical challenge. 2 3425551_2 (GHMatters) P90652.AU Summary of the Invention It is desirable to provide a steering wheel angle sensor device for ESP system, which not only can ensure successful installation and accurate positioning of a magnetic induction sensor in the limited space below the steering wheel, but also can transfer the rotation movement of the steering wheel to the magnetic induction sensor accurately. It is also desirable to provide an ESP system which comprises the steering wheel angle sensor device. In an aspect there is provided a steering wheel rotation angle sensor device for ESP of an automobile, which is mounted on the steering shaft connected to the steering wheel , and located between a combined switch and a clock spring mechanism fixed to the lower side of the steering wheel, comprising a magnetic induction sensor and a rotation angle transmission component , wherein, the upper end of upper tube section of the rotation angle transmission component and the lower end of the clock spring mechanism engage with each other so as to form a driving structure; a radial positioning mechanism that is used to position relative to the steering shaft and a first axial positioning mechanism that is able to deform elastically along the radial direction of the upper tube section are provided on the inner circumferential surface of the upper tube section; a second axial positioning mechanism that is able to deform elastically along the radial direction of the upper tube section is provided on the outer circumferential surface of the upper tube section; a third axial positioning mechanism is provided on an inner bushing of the magnetic induction sensor; and the outer circumferential surface of the upper tube section and the inner circumferential surface of the inner bushing engage with each other so as to form a circumferential lock driving mechanism. Also provided is an ESP system of an automobile, comprising a steering wheel rotation angle sensor device connected to an electronic control unit through signal wire, wherein, the steering wheel rotation angle sensor device is the steering wheel rotation angle sensor device described above. In some of the embodiments of the present invention, a steering angle sensor is mounted between the clock spring mechanism and the combined switch, and the clock spring serves as the driving part to drive the inner bushing of the steering angle sensor to rotate and thereby cut the magnetic lines of force, so as to implement steering angle and angular speed sensing function. In some of the embodiments of the present invention, the steering wheel angle sensor device for ESP employs a magnetic induction sensor that is more reliable, the magnetic induction sensor can be installed and positioned accurately in the limited installation space below the steering wheel, and the rotation movement of the steering wheel can be transferred to the magnetic induction sensor reliably to create a steering angle signal. The steering wheel angle sensor device provided in some of the embodiments of the present invention not only is more stable and reliable but also have higher sensitivity, longer service life, and higher reliability than grating sensors; in addition, the steering wheel angle sensor 3 3425551_2 (GHMatters) P90652.AU device is simple in structure, and the assembly of magnetic induction steering angle sensor can be implemented by adding an rotation angle transmission component and modifying the clock spring mechanism and steering shaft partially. Therefore, the steering wheel angle sensor device is low in cost and suitable for industrial production and product platform management. In addition, the steering angle sensor is mounted between the clock spring and the combined switch; the rotation angle transmission component that works with the steering angle sensor has a steering reset mechanism, which substitutes the steering reset mechanism of clock spring and successfully implements the steering reset function of the combined switch. Brief Description of the Accompanying Drawings Hereafter preferred embodiments of the present invention will be detailed with reference to the accompanying drawings. The above and other objects, features, and advantages of the present invention will be more apparent and understood more clearly in the following description: Figure 1 is a perspective view of the steering wheel rotation angle sensor device according to an embodiment of the present invention installed on the steering shaft. Figure 2 is schematic diagram of the clock spring mechanism described in the embodiment of the present invention fixed to the steering wheel. Figure 3 is a schematic assembly diagram of the rotation angle transmission component and clock spring mechanism described in the embodiment of the present invention. Figure 4 is a schematic diagram of the clock spring mechanism described in the embodiment of the present invention. Figure 5 is a perspective view of the rotation angle transmission component described in the embodiment of the present invention. Figure 6 is a perspective view of the rotation angle transmission component described in the embodiment of the present invention installed on the steering shaft. Figure 7 is another perspective view of the rotation angle transmission component described in the embodiment of the present invention. Figure 8 is a top view of the rotation angle transmission component described in the embodiment of the present invention, wherein a radial positioning mechanism and a first axial positioning mechanism in the rotation angle transmission component are shown. Figure 9 is an enlarged view of the radial positioning mechanism in the rotation angle transmission component in the embodiment of the present invention. Figure 10 is a schematic sectional view of the rotation angle transmission component described in the embodiment of the present invention, wherein the radial positioning 4 3425551_2 (GHMatters) P90652.AU mechanism and first axial positioning mechanism in the rotation angle transmission component are shown. Figure 11 is a perspective view of the steering wheel rotation angle sensor device according to the embodiment of the present invention, wherein the fitting structure between the magnetic induction sensor and the rotation angle transmission component is shown. Figure 12 is another perspective view of the steering wheel rotation angle sensor device according to the embodiment of the present invention, wherein a driving groove of the rotation angle transmission component for matching to the magnetic induction sensor and a second axial positioning mechanism are shown. Figure 13 is a sectional view of the steering wheel rotation angle sensor device according to the embodiment of the present invention installed on the steering shaft, wherein the fitting structure between magnetic induction steering angle sensor, rotation angle transmission component and steering shaft is shown. Figure 14 is a schematic diagram of fitting between a third axial positioning mechanism on the magnetic induction sensor and the rotation angle transmission component described in the embodiment of the present invention. Figure 15 is an enlarged view of the fitting between the locking projection of the magnetic induction sensor and the locking groove of the rotation angle transmission component described in the embodiment of the present invention. Figure 16 is a perspective view of the combined switch installed on the outer column tube of steering column below the rotation angle transmission component described in the embodiment of the present invention. Figure 17 is an illustrative sectional view of the combined switch installed on the outer column tube of steering column. and Figure 18 is another perspective view of the rotation angle transmission component, wherein the lower notches of the rotation angle transmission component are shown. Brief Description of the reference numbers: 1. Clock Spring Mechanism 2. Rotation Angle Sensor 3. Combined Switch 4. Steering Column 5. Rotation angle Transmission 6. Steering Shaft of Steering Column Component 7. Radial positioning Mechanism 8. Lower Tube Section of Rotation angle Transmission Component 9. First Claw 10. Upper Notch of Rotation angle Transmission Component 5 3426651_2 (GHMatters) P90652.AU 11. Lower Notch of Rotation angle 12. Second Claw Transmission Component 13. Upper Tube Section of Rotation angle 14. Fitting Projection of Clock Spring Transmission Component Mechanism 15. Steering Wheel 16. Fixing Pin 17. Upper Projection of Rotation angle 18. Outer Column Tube of Steering Transmission Component Column 19. Driving Groove of Rotation angle 20. Driving Projection of Magnetic Transmission Component Induction Sensor 21. Inner Bushing of Magnetic Induction 22. Third Claw Sensor 23. Steering Return Shifting Fork of 24. Axial positioning Groove of Steering Combined Switch Shaft 25. Retaining Flange of Combined 26. Connecting Portion of First Claw Switch 27. Retaining Portion of First Claw 28. First Insertion Groove 29. Connecting Portion of Second Claw 30. Retaining Portion of Second Claw 31. Second Insertion Groove Detailed Description of the Embodiments Hereunder the steering wheel rotation angle sensor device according to an embodiment of the present invention will be described in detail, with reference to the accompanying drawings. As shown in Figure 1, the steering wheel rotation angle sensor device according to the embodiment of the present invention comprises a magnetic induction sensor 2 and a rotation angle transmission component 5, the magnetic induction sensor 2 and the rotation angle transmission component 5 are assembled together and then mounted on the steering shaft 6 of a steering column 4 between a clock spring mechanism 1 and a combined switch 3. The steering wheel 15 (see Figure 2) is connected to the steering gear (not shown) of the automobile via the steering column 4, the steering column 4 comprises the steering shaft 6 and a outer column tube 18, the steering shaft 6 runs through the outer column tube 18 (see Figure 6) and can rotate in the outer column tube 18 relative to the outer column tube 18. Generally speaking, the outer column tube 18 is fixed to components such as instrument panel transverse beam bracket, etc., to support the steering shaft 6 and the steering wheel 15, etc., the upper section of steering shaft 6 protrudes from the outer tube 18, and the upper section of the steering shaft 6 6 3425551_2 (GHMatters) P90652.AU comprises thread portion and spline portion, etc. to install the steering wheel 15. A clock spring mechanism 1, a rotation angle transmission component 5 and a combined switch 3 described in the embodiment of the present invention are provided in sequence below the steering wheel 15, wherein the central through-hole of the clock spring mechanism 1 has a relative large diameter and doesn't contact with the steering shaft 6. Alternatively, since the steering wheel 15 rotates synchronously with the steering shaft 6, the central through-hole of the clock spring mechanism 1 can be smaller, as long as the steering shaft 6 can pass through it. An accurate positioning mechanism (see the following description) is provided between the rotation angle transmission component 5 and the steering shaft 6, so as to implement assembling and positioning between rotation angle transmission component 5 and steering shaft 6 and ensure coaxiality of rotation. The combined switch 3 is usually mounted on the outer column tube 18 of steering column 4, and has a central through-hole, so that the combined switch 3 can be inserted and fixed on the outer tube 18 of steering column 4. Hereunder the fitting structure of the components in the embodiments of the present invention will be described in detail with reference to Figures 2-8. It is noted that the fitting structure described below is only a preferred embodiment, many variants can be implemented within the scope of the present invention. As shown in Figure 2, in particularly, the clock spring mechanism 1 is fixed to the lower side of the steering wheel 15, so that it will rotate synchronously with the steering wheel 15 when the steering wheel 15 rotates. The clock spring mechanism 1 may be fixed to the steering wheel 15 by any means well known in the art, for example, in Figure 2, the clock spring mechanism 1 is fixed with a fixing pin 16. Also, it can be fixed with screws or snap-fits, etc. The clock spring mechanism 1 is an electrical rotary connector that is used in air bags of automobile, and it can provide a reliable electrical connection between two rotary parts that rotate relative to each other. The clock spring mechanism 1 mainly comprises a flexible flat cable, houses being rotatable relative to each other, wiring harness (i.e., lead-out wires) and connector, etc. When the steering wheel 15 is turned to left or right, the clock spring mechanism 1 can ensure normal electrical connection of electrical components such as air bags and horn switch, etc. In order to transfer the rotation of steering wheel 15 to the steering wheel rotation angle sensor device according to the embodiment of the device, the device utilizes the clock spring mechanism 1 mounted to the low portion of steering wheel 15 to achieve rotation angle transmission. As shown in Figures 3-5, the clock spring mechanism 1 has a central through-hole, so that the steering shaft 6 of steering column 4 can run through the clock spring mechanism 1. Two fitting projections 14 are formed at opposite positions on the low end of the clock spring mechanism 1, and the fitting projections 14 are designed to respectively fit with the upper notches 10 of an rotation angle transmission component 5 described below, so as to drive the 7 3425551_2 (GHMatters) P90652.AU rotation angle transmission component 5 to rotate synchronously with the steering wheel 15 and steering shaft 6. As shown in Figure 5, the rotation angle transmission component 5 is a hollow tube, which is designed to transfer the rotation of the steering wheel 15 to the magnetic induction sensor 2 described below. Two upper projections 17 are formed at opposite positions on the upper end of the rotation angle transmission component 5 respectively, and correspondingly, upper notches 10 are naturally formed between the two upper projections 17. In the case the rotation angle transmission component 5 is mounted on the steering shaft 6 below the clock spring mechanism 1, the fitting projections 14 on the lower end of the clock spring mechanism 1 are inserted into the corresponding upper notches 10 of the rotation angle transmission component 5, and thereby the clock spring mechanism 1 can further drive the rotation angle transmission component 5 to rotate when the steering wheel 15 rotates and drives the clock spring mechanism 1 to rotate. It is noted that a transmission structure in a different form can be formed between the lower end of clock spring mechanism 1 and the upper end of rotation angle transmission component 5, that is, the transmission structure is not limited to the aforesaid fitting structure in the form of the fitting projections 14 and upper notches 10, for example, a radial flange can be formed on the lower end of the clock spring mechanism 1, and a counter radial flange can be formed on the upper end of the rotation angle transmission component 5, and then the two radial flanges can be connected together by bolts. Hereafter a mounting structure that is used to mount the rotation angle transmission component 5 on the steering shaft 6 will be described with reference to Figures 6-10 and Figure 13. As shown in Figure 6, the rotation angle transmission component 5 in the embodiment of the present invention is mounted on a steering shaft 6 that protrudes from the outer column tube 18 below the steering wheel. Refer to Figures 7-10, as described above, the rotation angle transmission component 5 is a hollow tube, preferably, the hollow tube has the stepped-shape tube, wherein the upper tube section 13 of the rotation angle transmission component 5 is designed to fit with the steering shaft 6 and the magnetic induction sensor 2, while the lower tube section 8 is formed with lower notches 11 (see Figure 5), the lower notches 11 are mainly used to actuate the steering return shifting fork 23 of the combined switch 3 described below, to implement the steering return function of the combined switch 3. It is clearly seen from Figure 7 that the outer diameter of upper tube section 13 of rotation angle transmission component 5 is obviously less than the outer diameter of lower tube section 8, mainly in consideration that the lower notches of the lower tube section 8 needs to correspond to the position of the steering return shift fork 23 of combined switch 3. A radial positioning mechanism 7 and a first axial positioning mechanism that fit with the steering shaft 6 are formed on the inner circumferential surface of upper tube section 13 of rotation angle transmission component 5. Wherein, the radial positioning mechanism 7 may be in a variety of forms, for example, the radial 8 3425551_2 (GHMatters) P90662.AU positioning mechanism 7 may be projections that contact with the outer circumferential surface of steering shaft 6, preferably, as shown in Figures 7-10, the radial positioning mechanism 7 includes three protruded ribs which are arranged at an equal angular interval on the inner circumferential surface of upper tube section 13 of rotation angle transmission component 5 and extend in parallel in the axial direction of the rotation angle transmission component 5. When the rotation angle transmission component 5 is mounted on the steering shaft 6, said three protruded ribs contact with the outer circumferential surface of steering shaft 6, so creating a three-point positioning effect (in the condition of interference fit), and thereby achieves radial positioning of the rotation angle transmission component 5 relative to the steering shaft 6 and ensures coaxiality of rotation between rotation angle transmission component 5, steering shaft 6 and steering wheel 15. The first axial positioning mechanism includes two first claws 9 (alternatively, the quantity of the first claws 9 may be determined according to the situation of installation, but at least one first claw 9 is arranged). two first insertion grooves 28 are formed oppositely on the inner circumferential surface of upper tube section 13 of rotation angle transmission component 5 and extend in axial direction of upper tube section 13. The first insertion grooves 28 respectively extend downwards from the upper end of rotation angle transmission component 5 so that the length of each first insertion groove 28 is equal to a part of the length of upper tube section 13, that is, first insertion grooves 28 that extend downwards from the upper end of upper tube section 13 in the axial direction of upper tube section 13 are formed on the inner circumferential surface of upper tube section 13, and the extension length of each of the first insertion grooves 28 in the axial direction of upper tube section 13 is less than the length of the upper tube section 13. one first claw 9 is arranged in each first insertion groove 28, as shown in Figure 10, the first claw 9 comprises retaining portion 27 and connecting portion 26, wherein the lower end of connecting portion 26 is fixed to the bottom of the first insertion groove 28, so forming a cantilever structure that has flexibility, the flexibility is very important for successful installation of the rotation angle transmission component 5. Specifically, when the rotation angle transmission component 5 is mounted onto the steering shaft 6, the steering shaft 6 presses against the first claws 9, so that the first claws 9 deflect towards the side wall of corresponding first insertion groove 28, and thereby the rotation angle transmission component 5 can be fitted over the steering shaft 6 and mounted to an appropriate position successfully, when the rotation angle transmission component 5 is mounted to the required position on the steering shaft 6, the retaining portion 27 of the first claw 9 will fits into the groove 24 (see Figure 13) on the outer circumferential surface of steering shaft 6 by elastic resilience due to the flexibility of the first claw, and thereby the rotation angle transmission component 5 is positioned in axial direction of the steering shaft 6, so that the rotation angle transmission component 5 can't displace in axial direction of the steering shaft 6. Hereunder the fitting structure between magnetic induction sensor 2 and rotation angle transmission component will be detailed, with reference to Figures 11-15. 9 3426551_2 (GHMatters) P90652.AU As described above, the magnetic induction sensor 2 utilizes magnetic induction principle to produce the signal that represents the rotation angle of steering wheel and transfer the rotation angle signal to the ECU of ESP, so that the ECU can judge the present running state of the automobile and the driver's driving intention according to the rotation angle, change rate of rotation angle, and steering direction. The magnetic induction sensor 2 usually comprises housing, internal magnet, data lines and inner bushing that can rotate to cut the magnetic lines of force, etc. As shown in Figure 11, the magnetic induction sensor 2 is mounted on outer circumferential surface of upper tube section 13 of rotation angle transmission component 5 via its inner bushing 21, the inner bushing 21 of magnetic induction sensor 2 and the outer circumferential surface of upper tube section 13 of rotation angle transmission component 5 have a corresponding fitting structure respectively, so as to achieve positioning of the magnetic induction sensor 2 relative to the rotation angle transmission component 5 and enable the rotation angle transmission component 5 to drive the inner bushing 21 of magnetic induction sensor to rotate, the inner bushing 21 or other components driven by the inner bushing 21 cuts the magnetic lines of force produced by the internal magnet of magnetic induction sensor 2, and thereby the signals that represent steering wheel angle, steering direction, etc. are generated, and the signals are transmitted through the data lines to the ECU of ESP. As shown in Figure 12, a second axial positioning mechanism and driving grooves 19 are arranged on the outer circumferential surface of rotation angle transmission component 5, Wherein the second axial positioning mechanism is similar to the first axial positioning mechanism on the inner circumferential surface of rotation angle transmission component 5, and the second axial positioning mechanism includes four second claws 12 (alternatively, the quantity of the second claws 12 can be determined according to the condition of installation, but at least one second claw 12 is arranged), four second insertion grooves 31 are formed at an equal angular interval on the outer circumferential surface of upper tube section 13 of rotation angle transmission component 5 and extend in axial direction of rotation angle transmission component 5, the second insertion grooves 31 extend downwards from the upper end of rotation angle transmission component 5, so that the length of each second insertion grooves 31 is equal to a part of the length of upper tube section 13, that is to say, second insertion grooves 31 that extend from the upper end of upper tube section 13 in axial direction of upper tube section 13 are respectively formed on the outer circumferential surface of upper tube section 13, and the extension length of the second insertion groove 31 in axial direction of upper tube section 13 is less than the length of upper tube section 13, one second claw 12 is arranged in each second insertion groove 31, as shown in Figure 12, the second claw 12 comprises retaining portion 30 and connecting portion 29, wherein the lower end of connecting portion 29 is fixed to the bottom of the corresponding second insertion groove 31, so forming a cantilever structure that has flexibility, the flexibility is very important for successful installation of the magnetic induction sensor 2. Specifically, when the magnetic induction sensor 10 3425512 (GHMatters) P90652.AU 2 is mounted on the rotation angle transmission component 5, the inner circumferential surface of inner bushing 21 of magnetic induction sensor 2 presses against the second claws 12, so that the second claws 12 deflect towards the side wall of the second insertion grooves 31, and thereby the rotation angle transmission component 5 can be inserted and mounted to an appropriate position for the rotation angle transmission component 5 successfully, when the inner bushing 21 of magnetic induction sensor 2 is fitted on the outer circumferential surface of upper tube section 13 of rotation angle transmission component 5, as shown in Figure 11, the retaining portion 27 of each second claw 12 will be seized on the upper end of inner bushing 21 of magnetic induction sensor 2 by elastic resilience due to the flexibility of the second claw. However, the four second claws 12 on the rotation angle transmission component 5 can only prevent the magnetic induction sensor 2 from displacing upwards in axial direction on the outer circumferential surface of rotation angle transmission component 5, therefore, as shown in Figure 11 and Figure 14, a third axial positioning mechanism is provided on the upper end of inner bushing 21 of magnetic induction sensor 2, preferably, the third axial positioning mechanism is similar to the second axial positioning mechanism of rotation angle transmission component 5, and includes third claws 22 arranged oppositely, the third claw 22 comprises connecting portion and retaining portion, wherein the connecting portion of the third claw 22 is fixed to the upper end of inner bushing 21, when the inner bushing 21 of magnetic induction sensor 2 is mounted on the outer circumferential surface of upper tube section 13 of rotation angle transmission component 5, as shown in Figure 11, the two third claws 22 on the inner bushing 21 will catch on the upper end face of upper tube section 13 of rotation angle transmission component 5. Therefore, by means of the second claws 12 of rotation angle transmission component 5 and the third claws 22 of magnetic induction sensor, the magnetic induction sensor can not run upwards or downwards along the axial direction of the rotation angle transmission component 5. In addition, since the third axial positioning mechanism doesn't need to deform elastically to facilitate installation, it can be in a variety of known forms, for example, it may be a snap ring installed on the outer circumferential surface of rotation angle transmission component 5 on the lower end of inner bushing 21. Here, it is noted that the axial positioning arrangement achieved by first claws 9 and second claws 12 described above is only a preferred embodiment of installation, in view of the technical instructions provided in the embodiment of the present invention, other forms of installation can be used alternatively, for example, the first claws 9 and second claws 12 can be substituted by spring-loaded telescopic pins or elastic cards, though these substitutes are inferior to the claws in terms of component strength, convenience of installation, etc., they can generally ensure the installation of the steering wheel angle sensor device and can implement accurate axial positioning. It is seen that the technical essential of the first axial positioning mechanism and second axial positioning mechanism lies in: they can deform or deflect elastically along the radial direction of rotation angle transmission component 5 (or upper tube section 13). In addition, in the case of axial positioning achieved by the first claws 9 and second claws 12, since first insertion grooves 28 and second insertion grooves 31 have to be 11 3425551_2 (GHMatters) P90652.AU formed on the inner and outer circumferential surfaces of rotation angle transmission component 5 to receive the claws, preferably, the first claws 9 on the inner circumferential surface of rotation angle transmission component 5 and the second claws 12 on the outer circumferential surface are arranged in a staggered manner along the circumferential direction of rotation angle transmission component, so as to prevent the strength of rotation angle transmission component 5 from reduced too much as a result of severe reduction of wall thickness by the inner and outer insertion grooves 28 and 31. In this way, the first insertion grooves 28 for the first claws 9 and the second insertion grooves 31 for the second claws 12 can be arranged in a staggered manner on the inner and outer circumferential surfaces of rotation angle transmission component 5, so as to prevent the strength of rotation angle transmission component 5 from reduced too much. The first claws 9, second claws 12, and corresponding first insertion grooves 28 and second insertion grooves 31 may be formed by the process, such as slotting, cutting, or arc machining, etc., thus, the lower ends of connecting portions 26 and 30 of first claws 9 and second claws 12 will be integrally formed with the bottoms of corresponding insertion grooves, in this case, the strength and flexibility of the first claws 9 and second claws 12 during elastic deflection can be improved. To enable the rotation angle transmission component 5 to drive the inner bushing 21 of magnetic induction sensor 2 to rotate, as shown in Figure 11 and Figure 15, circumferential lock driving mechanism is formed on the outer circumferential surface of rotation angle transmission component 5 and the inner circumferential surface of inner bushing 21, for example, a driving groove 19 that extends in axial direction of rotation angle transmission component 5 is formed on the outer circumferential surface of rotation angle transmission component 5, and a driving projection 20 that cooperates with the driving groove 19 is formed on the inner circumferential surface of inner bushing 21, when the inner bushing 21 of magnetic induction sensor 2 is fitted on the outer circumferential surface of upper tube section 13 of rotation angle transmission component 5, as shown in Figure 15, the driving projection 20 will be inserted into the driving groove 19, and thereby the rotation angle transmission component 5 can drive the inner bushing 21 of magnetic induction sensor 2 to rotate due to the engagement between driving groove 19 and driving projection 20 when the rotation angle transmission component 5 rotates. In this way, the rotation of steering wheel 15 can be transferred accurately to the magnetic induction sensor 2. More preferably, as shown in Figures 16-18, the rotation angle transmission component 5 further comprises lower tube section 8 which has two lower notches 11 in different sizes, the lower notches 11 are mainly used to shift the steering return shifting fork 23 of combined switch 3, so as to implement the steering reset function for combined switch 3. In the prior art, the function is usually implemented by means of lower notches on the clock spring mechanism 1, and in the present invention, owing to the fact that the steering wheel rotation angle sensor device according to the embodiments of the present invention is mounted between clock spring mechanism 1 and combined switch 3, the lower notches 11 are arranged on the lower tube section 8 12 34255651_2 (GHMatters) P90652.AU of rotation angle transmission component 5. When the automobile turns, the driver switches on the turn light, after the entire automobile turns, the direction of steering wheel will be return, at that time, the lower notches 11 on the lower tube section of rotation angle transmission component 5 will drive the steering reset shift fork 23 of the combined switch, so as to accomplish the steering return function of the combined switch. The combined switch 3 is mainly used to control the electrical elements such as turn lights, fog lights, and head lights of the automobile, and is usually mounted on the outer column tube 18 of steering column 4, the form of mounting can be determined according to the structure of combined switch 3. Figure 17 only illustrates a specific form of mounting, wherein the combined switch 3 is mounted on the outer column tube 18 of steering column 4 mainly by means of a retaining flange 25. Hereunder the operating process of the steering wheel rotation angle sensor device according to the embodiments of the present invention will be described. When the driver manipulates the automobile to turn, the steering wheel 15 will drive the clock spring mechanism 1 to rotate, and the clock spring mechanism 1 drives the rotation angle transmission component 5 to rotate synchronously via the fitting projection 14 on the lower end of the clock spring mechanism 1. The radial positioning mechanism 7 and first claws 9 are arranged on the inner circumferential surface of rotation angle transmission component 5, to ensure achieve radial positioning and axial positioning relative to the steering shaft 6 and ensure coaxiality and synchronization of rotation between the rotation angle transmission component 5 and the steering shaft 6. Circumferential lock driving mechanism (i.e., the driving groove 19 and driving projection 20 described above) and second claws 12 are arranged on the outer circumferential surface of rotation angle transmission component 5; wherein positioning in circumferential direction and rotation angle transmission are implemented by means of the engagement between the driving groove 19 and the driving projection 20 on magnetic induction sensor 2, and axial positioning relative to the magnetic induction sensor 2 is implemented by means of the second claws 12, therefore, the rotation angle transmission component 5 drives the inner bushing 21 of magnetic induction sensor 2 to rotate and thereby cut the magnetic lines of force produced by an internal magnet in the induction sensor 2, as a result, a steering angle signal is generated. In addition, the ESP system provided in the embodiment of the present invention comprises the above-mentioned steering wheel angle sensor device. It is seen from above description that, in the embodiment of the present invention, the steering wheel rotation angle sensor device for ESP employs a magnetic induction sensor 2 that is more reliable, the magnetic induction sensor 2 can be installed and positioned accurately in the limited installation space below the steering wheel 15, and the rotation of the steering wheel 15 can be transferred to the magnetic induction sensor 2 reliably to create a rotation angle signal. The steering wheel rotation angle 13 34255512 (GHMatters) P90652.AU sensor device according to the embodiment of the present invention not only is stable and reliable but also has long service life and simple structure, the assembly of magnetic induction steering angle sensor 2 can be implemented by adding an rotation angle transmission component 5 and modifying the clock spring mechanism 1 and steering shaft 6 partially. Therefore, the steering wheel angle sensor device is low in cost and suitable for industrial production and product platform management. Other embodiments can be implemented within the scope of the present invention. Those skilled in the art can make a variety of variations on the basis of the embodiment of the present invention, however, these simple variations and variants shall be deemed as falling into the protect scope of the present invention as defined by the claims. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 14 34255512 (GHMatters) P90652.AU

Claims

1. A steering wheel rotation angle sensor device for an ESP system of an automobile, the device being mounted on the steering shaft connected to the steering wheel and located between a combined switch and a clock spring mechanism fixed to the lower side of the steering wheel the device comprising a magnetic induction sensor and a rotation angle transmission component wherein, the upper end of an upper tube section of the rotation angle transmission component and the lower end of the clock spring mechanism engage with each other so as to form a driving structure; a radial positioning mechanism that is used to determine the position relative to the steering shaft and a first axial positioning mechanism that is able to deform elastically along the radial direction of the upper tube section are provided on the inner circumferential surface of the upper tube section a second axial positioning mechanism that is able to deform elastically along the radial direction of the upper tube section is provided on the outer circumferential surface of the upper tube section a third axial positioning mechanism is provided on an inner bushing of the magnetic induction sensor; and the outer circumferential surface of the upper tube section and the inner circumferential surface of the inner bushing engage with each other so as to form a circumferential lock driving mechanism.

2. The steering wheel rotation angle sensor device according to claim 1, wherein, the first axial positioning mechanism comprises a first claw, which comprises a connecting portion and a retaining portion; a first insertion groove is formed on the inner circumferential surface of the upper tube section, which is extended downwards from the upper end of the upper tube section in an axial direction, and the extension length thereof is less than the length of the upper tube section; the lower end of the connecting portion of the first claw is fixed to the bottom of the first insertion groove, so that the first claw is formed as an elastic cantilever structure; and the retaining portion of the first claw is engaged in a positioning groove formed on the outer circumferential surface of the steering shaft. 15 34255512 (GHMatters) P90652.AU

3. The steering wheel rotation angle sensor device according to claim 2, wherein, the first axial positioning mechanism comprises two of said first claws arranged oppositely.

4. The steering wheel rotation angle sensor device according to any one of the preceding claims, wherein, the second axial positioning mechanism comprises a second claw, which comprises a connecting portion and a retaining portion; a second insertion groove is formed on the outer circumferential surface of the upper tube section, which is extended downwards from the upper end of the upper tube section in axial direction, and the extension length thereof is less than the length of the upper tube section; the lower end of the connecting portion of the second claw is fixed to the bottom of the second insertion groove, so that the second claw is formed as an elastic cantilever structure; and the retaining portion of the second claw is seized on the upper end of the inner bushing of said magnetic induction sensor.

5. The steering wheel rotation angle sensor device according to claim 4, wherein, the second axial positioning mechanism comprises four of said second claws arranged at an equal angular interval.

6. The steering wheel rotation angle sensor device according any one of the preceding to claims, wherein, the third axial positioning mechanism comprises a third claw, which comprises a connecting portion and a retaining portion; the lower end of the connecting portion of the third claw is fixed to the upper end of the inner bushing; and the retaining portion of the third claw is seized on the upper end of upper tube section.

7. The steering wheel rotation angle sensor device according to claim 6, wherein, the third axial positioning mechanism comprises two said third claws arranged oppositely.

8. The steering wheel rotation angle sensor device according to any one of the preceding claims, wherein, the driving structure between the rotation angle transmission component and the clock spring mechanism comprises a upper notch 16 3425551_2 (GHMatters) P90652.AU formed on the upper end of the upper tube section and a fitting projection formed on the lower end of the clock spring mechanism.

9. The steering wheel rotation angle sensor device according to any one of the preceding claims, wherein, said circumferential lock driving mechanism comprises a driving groove formed on the outer circumferential surface of the upper tube section and a driving projection formed on the inner circumferential surface of the inner bushing, and the driving projection is inserted in the driving groove.

10. The steering wheel rotation angle sensor device according to any one of the preceding claims, wherein, the radial positioning mechanism comprises three protruded ribs formed on the inner circumferential surface of the upper tube section, which are arranged at an equal angular interval and extended in axial direction of the upper tube section; and the three protruded ribs are contacted with the outer circumferential surface of the steering shaft.

11. The steering wheel rotation angle sensor device according to any one of the preceding claims, wherein, the rotation angle transmission component further comprises a lower tube section, which has two lower notches being used to shift a steering return shifting fork of the combined switch.

12. A steering wheel rotation angle sensor device substantially as herein described with reference to the accompanying drawings.

13. An ESP system of an automobile, comprising a steering wheel rotation angle sensor device connected to an electronic control unit through signal wire, wherein, the steering wheel rotation angle sensor device is the steering wheel rotation angle sensor device according to any one of claims 1-12

14. An ESP system of an automobile substantially as herein described with reference to the accompanying drawings. 17 3425551_2 (GHMatters) P90652.AU