Redundant angle sensor for automobile steering system

Abstract

The invention relates to a redundant angle sensor for an automobile steering system, and the angle sensor comprises a detection wheel which is provided with a thread on the surface; a worm gear is arranged at the first end of the transmission rod, a first gear is arranged at the second end, the worm gear is meshed with the detection wheel, and a first metal target is arranged on the first gear; the circuit board is provided with a first induction circuit and a second induction circuit; the second gear is meshed with the first gear, and a second metal target is arranged on the second gear; the processing unit is used for determining the steering wheel rotation angle. The detection wheel has the advantages that the installation is convenient, and the detection wheel is only required to be assembled with the shaft body of the automobile steering system; calibration is convenient, and calibration can be realized by compensating sine and cosine signals; double induction circuits and double metal targets are arranged, so that mutual verification can be realized; the difference between the number of teeth of the first gear and the number of teeth of the second gear is one, a vernier algorithm can be applied, the electrical angle combination output by the first induction circuit and the second induction circuit has uniqueness when the steering wheel is at any angle, and the detection precision is high.

Description

Technical Field

[0001] The present invention relates to the field of angle sensors, and in particular to a redundant angle sensor used in an automobile steering system. Background Art

[0002] Traditional angle sensor designs require numerous mechanical components for assembly, and welding and calibration are required for final assembly at the customer's end. This complex and demanding process requires a single workstation. Traditional torque sensors require welding of the magnetic ring and the sensor body before online calibration can be performed. This calibration process is susceptible to the effects of the magnetic ring's hysteresis and the magnetic conductivity of the magnetic structure. Furthermore, these sensors typically consist of two components, requiring high concentricity during installation, and are prone to abnormal noise over time. Summary of the Invention

[0003] The present invention mainly solves the problems of complex assembly and susceptibility to interference of traditional angle sensors, and provides a redundant angle sensor for automobile steering systems. It is easy to install and calibrate, and is equipped with dual induction coils that can verify each other and can output accurate angle values based on the electrical information of the two induction coils through a vernier algorithm.

[0004] The technical solution adopted by the present invention to solve the technical problem is a redundant angle sensor for an automobile steering system, comprising: The detection wheel has threads on its surface and is rotated by the car's steering wheel; A transmission rod, having a worm gear at the first end and a first gear at the second end, wherein the worm gear is engaged with the detection wheel, and a first metal target is provided on the first gear; a circuit board, wherein a first induction circuit and a second induction circuit are provided on the circuit board, and the first gear corresponds to the first induction circuit; a second gear meshing with the first gear, a second metal target being provided on the second gear, and the second gear corresponding to the second induction circuit; The processing unit is used to receive the electrical signals from the first sensing circuit and the second sensing circuit and determine the steering wheel rotation angle.

[0005] As a preferred solution of the above scheme, it includes a shell, which includes a cover and a base plate. The circuit board is fixedly arranged on the front side of the base plate. A through hole is provided on the base plate. A mounting tube is provided on the back side of the base plate corresponding to the through hole. The transmission rod is located in the mounting tube and the through hole.

[0006] As a preferred embodiment of the above scheme, a limiting groove is provided on the transmission rod, and an axis retaining spring is provided outside the mounting tube. The limiting protrusion on the axis retaining spring passes through the hollow on the mounting tube and extends into the limiting groove of the transmission rod.

[0007] As a preferred embodiment of the above solution, the number of teeth of the first gear and the second gear differ by one.

[0008] As a preferred embodiment of the above scheme, the blade width of the first metal target is 1 / 4 of the sin+ and cos+ widths of the induction coil, the blade part of the first metal target is symmetrical with the blank part, and the second metal target has the same structure as the first metal target.

[0009] As a preferred embodiment of the above solution, the first metal target and the first gear are coaxially arranged, and the second metal target and the second gear are coaxially arranged.

[0010] As a preferred solution of the above solution, a humidity sensor and a heating module are provided on the circuit board.

[0011] As a preferred solution of the above solution, the cover body is provided with mounting ears.

[0012] As a preferred embodiment of the above solution, a conformal coating is provided on the circuit board.

[0013] The advantages of the present invention are: easy installation, only the detection wheel needs to be assembled with the shaft of the automobile steering system; easy calibration, which can be achieved by compensating the sine and cosine signals; dual sensing circuits and bimetallic targets are provided, which can calibrate each other; the number of teeth of the first gear and the second gear differ by one, and a vernier algorithm can be applied to ensure that the electrical angle combination output by the first sensing circuit and the second sensing circuit is unique when the steering wheel is at any angle, and the detection accuracy is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the structure of the redundant angle sensor.

[0015] Figure 2 Schematic diagram of the explosion structure of the redundant angle sensor.

[0016] Figure 3 for Figure 2 A partial enlarged view of area A in the middle.

[0017] 1-Detection wheel 2-Transmission rod 3-Housing 4-Worm gear 5-Base plate 6-Second induction circuit 7-First induction circuit 8-Second metal target 9-First metal target 10-Second gear 11-First gear 12-Cover 13-Circuit board 14-Limiting groove 15-Shaft retaining spring 16-Mounting cylinder 17-Hollowout 18-Limiting protrusion. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be further described below with reference to embodiments and in conjunction with the accompanying drawings.

[0019] Example: This embodiment is a redundant angle sensor for a vehicle steering system, such as Figures 1 to 2 As shown, it includes a detection wheel 1, a transmission rod 2, and a housing 3. A first gear 11, a second gear 10, and a circuit board 13 are provided within the housing. The housing 3 includes a cover 12 and a base plate 5. The cover is provided with mounting ears, and the circuit board 13 is fixedly mounted on the front of the base plate 5. The detection wheel 1 is provided with threads on its surface, and the detection wheel is driven to rotate by the vehicle steering wheel. A worm gear 4 is provided at the first end of the transmission rod 2, and a first gear 11 is fixed to the second end of the transmission rod. The worm gear 4 is located outside the housing 3 and meshes with the detection wheel 1. The first gear is located within the housing 3, and a first metal target 9 is provided on the first gear 11. The second gear 10 is rotatably connected to the base plate 5 and meshes with the first gear 11. A second metal target 8 is provided on the second gear 10. The circuit board 13 is provided with a first sensing circuit 7 and a second sensing circuit 6 at locations corresponding to the first and second metal targets. When the vehicle's steering wheel turns, the detection wheel rotates accordingly, driving the worm gear 4, which in turn rotates the first gear. Simultaneously, the first gear drives the second gear, which in turn drives the first and second metal targets, respectively, causing the first and second sensing circuits on the circuit board to generate electrical signals. The processing unit on the circuit board calculates the steering wheel angle based on the electrical signals from the first and second sensing circuits. The design of dual metal targets and dual sensing circuits allows the calculation results of the two sensing circuits to be cross-checked, ensuring the accuracy of the detection results and allowing the vehicle system to promptly detect angle sensor failures. Furthermore, the circuit board is equipped with a conformal coating and integrates a humidity sensor and a heating module. The humidity sensor detects humidity in the vehicle's steering system. When humidity is low, the heating module removes moisture to prevent water mist from affecting the detection results. When humidity is high, an alarm is directly sent to the vehicle system to promptly alert the driver.

[0020] like Figure 3 As shown, the base plate has a through-hole, and a mounting tube 16 is located on the back of the base plate corresponding to the through-hole. The transmission rod is located between the mounting tube and the through-hole. A retaining groove 14 is provided on the transmission rod, and a shaft retaining spring 15 is located outside the mounting tube. A retaining protrusion 18 on the shaft retaining spring 15 passes through a hollow 17 in the mounting tube 16 and extends into the retaining groove of the transmission rod. The shaft retaining spring can limit the axial position of the transmission shaft without affecting its rotation.

[0021] The first metal target 9 is coaxially arranged with the first gear 11, and the second metal target 8 is coaxially arranged with the second gear 10. The number of teeth of the first gear 11 and the second gear 10 differs by one. The blade width of the first metal target is 1 / 4 of the sin+ and cos+ widths of the induction coil. The blade portion of the first metal target is symmetrical with the blank portion. The second metal target has the same structure as the first metal target.

[0022] In this embodiment, the first metal target 9 and the second metal plate 8 are provided with 4 blades, each blade has an angle of 45 degrees, and the blank angle between adjacent blades is also 45 degrees. The number of teeth of the first gear 11 is 18 teeth, and the number of teeth of the second gear 10 is 17 teeth. When the second gear rotates one circle, the second sensing circuit outputs 4 360-degree electrical angle signals, which are equal to 4 90-degree physical angle signals after processing. At the same time, the first gear meshing with the second gear only rotates 340 degrees, that is, 4 340-degree electrical angle signals, which are equal to 4 85-degree physical angle signals after processing. The least common multiple of 90 and 85 is 1530. If the initial relative position of the first gear and the second gear is defined as zero, when the second gear actively rotates 1530 physical degrees, the first gear also passively rotates 1530 physical degrees, and the first gear and the second gear return to zero. During the rotation from zero to zero, the relative position of the first gear and the second gear is unique. That is, the electrical angle combination output by the first sensing circuit and the second sensing circuit is unique. Therefore, the vernier algorithm can be used for calculation to ultimately obtain a linearized angle output curve.

[0023] The maximum steering wheel rotation angle of a normal family car usually does not exceed ±720 degrees, and even with a safety margin, it is still within the range of 1530 degrees. Therefore, there is a specific set of electrical angle combinations corresponding to any steering wheel angle, based on which the steering wheel angle can be accurately detected. In addition, the steering wheel angle can also be calculated separately based on the electrical angles of the first sensing circuit and the second sensing circuit. That is, the angle sensor in this embodiment can perform triple redundant detection based on the first sensing circuit, the second sensing circuit, and the first sensing circuit and the second sensing circuit, respectively, to ensure the accuracy of the detection and to detect sensor failures in a timely manner. At the same time, based on the above principles, the angle sensor can achieve rapid calibration by compensating the sine and cosine signals.

[0024] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A redundant angle sensor for an automobile steering system, comprising: The detection wheel has threads on its surface and is rotated by the car's steering wheel; A transmission rod, having a worm gear at the first end and a first gear at the second end, the worm gear being engaged with the detection wheel, and a first metal target being provided on the first gear; a circuit board, wherein a first induction circuit and a second induction circuit are provided on the circuit board, and the first gear corresponds to the first induction circuit; a second gear meshing with the first gear, a second metal target being provided on the second gear, and the second gear corresponding to the second induction circuit; The processing unit is used to receive the electrical signals from the first sensing circuit and the second sensing circuit and determine the steering wheel rotation angle.

2. The redundant angle sensor for an automobile steering system according to claim 1, wherein: It includes a shell, which includes a cover and a base plate. The circuit board is fixedly arranged on the front of the base plate. A through hole is provided on the base plate. A mounting cylinder is provided on the back of the base plate corresponding to the through hole. The transmission rod is located in the mounting cylinder and the through hole.

3. The redundant angle sensor for an automobile steering system according to claim 2, wherein: A limiting groove is provided on the transmission rod, and an axis retaining spring is provided outside the installation tube. The limiting protrusion on the axis retaining spring passes through the hollow on the installation tube and extends into the limiting groove of the transmission rod.

4. The redundant angle sensor for an automobile steering system according to claim 1, wherein: The number of teeth of the first gear and the second gear differs by one.

5. The redundant angle sensor for an automobile steering system according to claim 1, wherein: The blade width of the first metal target is 1 / 4 of the sin+ and cos+ widths of the induction coil, the blade portion of the first metal target is symmetrical to the blank portion, and the second metal target has the same structure as the first metal target.

6. The redundant angle sensor for an automobile steering system according to claim 1 or 5, characterized in that: The first metal target and the first gear are coaxially arranged, and the second metal target and the second gear are coaxially arranged.

7. The redundant angle sensor for an automobile steering system according to claim 1 or 5, characterized in that: A humidity sensor and a heating module are provided on the circuit board.

8. The redundant angle sensor for an automobile steering system according to claim 2, wherein: The cover body is provided with mounting ears.

9. The redundant angle sensor for an automobile steering system according to claim 1, wherein: The circuit board is provided with a conformal coating.

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