A redundant angle sensor for a vehicle steering system

Abstract

This invention relates to a redundant angle sensor for an automotive steering system, comprising: a detection wheel with threads on its surface; a transmission rod with a worm gear at one end and a first gear at the second end, the worm gear meshing with the detection wheel, and a first metal target mounted on the first gear; a circuit board with a first sensing circuit and a second sensing circuit; a second gear meshing with the first gear, and a second metal target mounted on the second gear; and a processing unit for determining the steering wheel rotation angle. The advantages of this invention are: convenient installation, requiring only the assembly of the detection wheel with the shaft of the automotive steering system; convenient calibration, achieved through compensation of sine and cosine signals; dual sensing circuits and dual metal targets for mutual verification; and a difference of one tooth count between the first and second gears, allowing the application of a vernier algorithm to ensure that the electrical angle combination output by the first and second sensing circuits is unique at any steering wheel angle, resulting in high detection accuracy.

Description

Technical Field

[0001] This invention relates to the field of angle sensors, and more particularly to a redundant angle sensor for automotive steering systems. Background Technology

[0002] Traditional angle sensor designs require numerous mechanical components for assembly, necessitating welding and calibration at the customer end, resulting in complex and demanding single-station processes. Traditional torque sensors require welding of the magnetic ring and the sensor body at the customer end before online calibration can be performed. Furthermore, the calibration process is susceptible to the effects of the magnetic ring's hysteresis and the magnetic conductivity of the guiding mechanism. Additionally, these sensors are typically composed of two parts, requiring high concentricity during installation, and are prone to developing abnormal noises over time. Summary of the Invention

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

[0004] The technical solution adopted by this invention to solve its technical problem is a redundant angle sensor for an automotive steering system, comprising:

[0005] The inspection wheel has threads on its surface and is driven to rotate by the car steering wheel;

[0006] The transmission rod has a worm gear at the first end and a first gear at the second end. The worm gear meshes with the detection wheel, and a first metal target is provided on the first gear.

[0007] A circuit board, wherein a first sensing circuit and a second sensing circuit are provided on the circuit board, and the first gear corresponds to the first sensing circuit;

[0008] The second gear meshes with the first gear, and the second gear is provided with a second metal target. The second gear corresponds to the second sensing circuit.

[0009] The processing unit is used to receive electrical signals from the first sensing circuit and the second sensing circuit and determine the steering wheel rotation angle.

[0010] As a preferred embodiment of the above solution, the system includes a housing, which comprises a cover and a base plate. The circuit board is fixedly mounted on the front side of the base plate, and the base plate has a through hole. A mounting cylinder is provided on the back side of the base plate corresponding to the through hole, and the transmission rod is located in the mounting cylinder and the through hole.

[0011] As a preferred embodiment of the above solution, the transmission rod is provided with a limiting groove, and the mounting cylinder is provided with a shaft retainer. The limiting protrusion on the shaft retainer passes through the hollow on the mounting cylinder and extends into the limiting groove of the transmission rod.

[0012] As a preferred embodiment of the above scheme, the number of teeth of the first gear and the second gear differs by one.

[0013] As a preferred embodiment of the above scheme, the blade width of the first metal target is 1 / 4 of the sin+ and cos+ width 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.

[0014] As a preferred embodiment of the above scheme, the first metal target and the first gear, and the second metal target and the second gear are coaxially arranged.

[0015] As a preferred embodiment of the above solution, the circuit board is equipped with a humidity sensor and a heating module.

[0016] As a preferred embodiment of the above solution, the cover is provided with mounting ears.

[0017] As a preferred embodiment of the above solution, the circuit board is provided with a conformal coating.

[0018] The advantages of this invention are: easy installation, requiring only the assembly of the detection wheel with the axle of the car steering system; easy calibration, which can be achieved by compensating for sine and cosine signals; equipped with dual sensing circuits and bimetallic targets, enabling mutual verification; the difference in the number of teeth between the first and second gears is one, allowing the application of a vernier algorithm to ensure that the electrical angle combination output by the first and second sensing circuits is unique at any angle of the steering wheel, resulting in high detection accuracy. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a redundant angle sensor.

[0020] Figure 2 This is a schematic diagram of the exploded structure of a redundant angle sensor.

[0021] Figure 3 for Figure 2 A magnified view of a portion of region A in the middle.

[0022] 1-Detection wheel 2-Transmission rod 3-Housing 4-Worm gear 5-Base plate 6-Second sensing circuit 7-First sensing 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 snap ring 16-Mounting cylinder 17-Hollowing 18-Limiting protrusion. Detailed Implementation

[0023] The technical solution of the present invention will be further described below through embodiments and in conjunction with the accompanying drawings.

[0024] Example:

[0025] This embodiment describes a redundant angle sensor for automotive steering systems, such as... Figures 1 to 2 As shown, the device includes a detection wheel 1, a transmission rod 2, and a housing 3. The housing contains a first gear 11, a second gear 10, and a circuit board 13. The housing 3 includes a cover 12 and a base plate 5. The cover has mounting ears, and the circuit board 13 is fixedly mounted on the front of the base plate 5. The detection wheel 1 has threads on its surface and is rotated by a car steering wheel. The first end of the transmission rod 2 has a worm gear 4. The 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 11 is located inside the housing 3 and has a first metal target 9. The second gear 10 is rotatably connected to the base plate 5 and meshes with the first gear 11. The second gear 10 has a second metal target 8. The circuit board 13 has a first sensing circuit 7 and a second sensing circuit 6 corresponding to the first and second metal targets. When the car steering wheel is turned, the detection wheel rotates accordingly, driving the worm gear 4 to rotate, which in turn causes the first gear to rotate. Simultaneously, the first gear drives the second gear to rotate, and the first and second gears respectively drive the first and second metal targets to rotate, generating electrical signals in the first and second sensing circuits on the circuit board. The processing unit on the circuit board calculates the steering wheel rotation angle based on these electrical signals. The design of the 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 enabling the vehicle's infotainment system to promptly detect angle sensor malfunctions. Furthermore, the circuit board has a conformal coating and integrates a humidity sensor and a heating module. The humidity sensor detects the humidity in the car's steering system. When the humidity is low, the heating module dehumidifies to prevent water mist from affecting the detection results. When the humidity is high, it directly alerts the vehicle's infotainment system to promptly remind the driver.

[0026] like Figure 3 As shown, a through hole is provided on the base plate, and a mounting cylinder 16 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. A limiting groove 14 is provided on the transmission rod, and a shaft retaining spring 15 is provided outside the mounting cylinder. The limiting protrusion 18 on the shaft retaining spring 15 passes through the hollow 17 on the mounting cylinder 16 and extends into the limiting groove of the transmission rod. The shaft retaining spring can axially limit the transmission shaft without affecting its rotation.

[0027] The first metal target 9 and the first gear 11, and the second metal target 8 and the second gear 10 are coaxially arranged, with the number of teeth of the first gear 11 and the second gear 10 differing by one. The blade width of the first metal target is 1 / 4 of the sin+ and cos+ width of the induction coil, and the blade portion of the first metal target is symmetrical to the blank portion. The second metal target has the same structure as the first metal target.

[0028] In this embodiment, the first metal target 9 and the second metal plate 8 are provided with 4 blades, each blade with an angle of 45 degrees, and the blank angle between adjacent blades is also 45 degrees. The first gear 11 has 18 teeth, and the second gear 10 has 17 teeth. When the second gear rotates one revolution, the second sensing circuit outputs four 360-degree electrical angle signals, which are processed to equal four 90-degree physical angle signals. At the same time, the first gear meshing with the second gear only rotates 340 degrees, that is, four 340-degree electrical angle signals, which are processed to equal four 85-degree physical angle signals. 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 by 1530 physical degrees, the first gear also passively rotates by 1530 physical degrees. 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 to calculate and finally obtain the linearized angle output curve.

[0029] The maximum steering wheel rotation angle of a normal passenger car typically does not exceed ±720 degrees, and even with a safety margin, it remains within the range of 1530 degrees. Therefore, any angle of the steering wheel corresponds to a specific set of electrical angle combinations, based on which the steering wheel angle can be accurately detected. Furthermore, the steering wheel angle can also be calculated independently based on the electrical angles of the first and second sensing circuits. That is, the angle sensor in this embodiment can perform triple redundant detection based on the first and second sensing circuits, as well as the first and second sensing circuits themselves, ensuring detection accuracy and timely detection of sensor malfunctions. Simultaneously, based on the above principles, this angle sensor can achieve rapid calibration by compensating for sine and cosine signals.

[0030] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A redundant angle sensor for an automotive steering system, characterized in that it comprises: The inspection wheel has threads on its surface and is driven to rotate by the car steering wheel; The transmission rod has a worm gear at the first end and a first gear at the second end. The worm gear meshes with the detection wheel, and a first metal target is provided on the first gear. A circuit board, wherein a first sensing circuit and a second sensing circuit are provided on the circuit board, and the first gear corresponds to the first sensing circuit; The second gear meshes with the first gear, and the second gear is provided with a second metal target. The second gear corresponds to the second sensing circuit. The processing unit is used to receive electrical signals from the first sensing circuit and the second sensing circuit and determine the steering wheel rotation angle; The housing includes a cover and a base plate. The circuit board is fixedly mounted on the front of the base plate. The base plate has a through hole. The back of the base plate has a mounting cylinder corresponding to the through hole. The transmission rod is located in the mounting cylinder and the through hole.

2. A redundant angle sensor for a vehicle steering system according to claim 1, characterized in that: The transmission rod is provided with a limiting groove, and the mounting cylinder is provided with a shaft retainer. The limiting protrusion on the shaft retainer passes through the hollow on the mounting cylinder and extends into the limiting groove of the transmission rod.

3. The redundant angle sensor for automotive steering systems of claim 1, wherein: The number of teeth on the first gear differs from that on the second gear by one.

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

5. A redundant angle sensor for automotive steering systems according to claim 1 or 4, characterized in that: The first metal target and the first gear, and the second metal target and the second gear are coaxially arranged.

6. The redundant angle sensor for automotive steering systems according to claim 1 or 4, characterized in that: The circuit board is equipped with a humidity sensor and a heating module.

7. The redundant angle sensor for automotive steering systems of claim 1, wherein: The cover is equipped with mounting ears.

8. The redundant angle sensor for automotive steering systems of claim 1, wherein: The circuit board has a conformal coating.

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