Steering Sensor Integrating Torque and Angle Detection
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Solution Overview
Problem
Existing sensor devices for detecting torque and rotation angle in steering systems have a high number of components and mounting steps, leading to increased costs and difficulty in securing mounting space without interfering with other devices.
Innovation Solution
A sensor device with integrated torque and rotation angle detection using soft magnetic bodies, permanent magnets, and magnetic sensors, where the torque detection magnetic sensor and rotation angle detection magnetic sensor are mounted on a single circuit board, reducing the number of components and mounting steps, and the device protrudes only in one radial direction, minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the torque sensor and rotation angle sensor are attached to the case member with separate mounting, then each sensor can function independently, but the number of components and mounting steps increases
Solution Approach 1:
The patent combines the torque sensor and rotation angle sensor into a single integrated sensor device. The magnetic sensor detects both the magnetic field changes caused by torque (through the yoke and cylindrical magnet interaction) and the magnetic field changes caused by rotation angle (through the detection gear and magnets). This merging of functions into one device reduces the number of components and mounting steps while maintaining detection accuracy for both torque and rotation angle.
2Measurement precision
If the torque sensor and rotation angle sensor protrude in radial direction of the column shaft, then the sensors can be positioned for detection, but the mounting space becomes limited and interference with other devices occurs
Solution Approach 1:
The patent repositions the sensor device so that it protrudes in the axial direction of the column shaft rather than the radial direction. The magnetic sensor is arranged axially relative to the column shaft, with the yoke and cylindrical magnet configured to detect torque through axial magnetic field interactions. This dimensional change in mounting orientation reduces radial space requirements and avoids interference with other steering system components while maintaining detection precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the number of components and mounting steps, lowers costs, and improves mountability on vehicles by minimizing space requirements and avoiding interference with other devices.
Implementation Method 1
The torque detection magnetic sensor is configured to detect a magnetic field generated between the facing portions. The magnetic field detected by the torque detection magnetic sensor changes based on a twisting amount of the torsion shaft.
Implementation Method 2
The rotation angle detection magnetic sensor is configured to detect a magnetic field of the rotation angle detection permanent magnet. The magnetic field detected by the rotation angle detection magnetic sensor changes based on the rotation angle of the shaft.
Implementation Method 3
The torque detection permanent magnet is configured to generate a magnetic flux in a magnetic path including the pair of soft magnetic bodies.
Data Source
AI summary
A sensor device where the number of components and mounting steps can be reduced and mountability on a mounting target is improved. A sensor device configured to detect a torque applied to a pinion shaft and pinion shaft's rotation angle. The pinion shaft is formed by coupling an input shaft and output shaft together by a torsion bar. The sensor device includes a torque detecting portion wherein magnetic fields detected by torque detection magnetic sensors change based on the torsion bar's twisting amount, a rotation angle detecting portion wherein magnetic fields detected by rotation angle detection magnetic sensors change based on the pinion shaft's rotation angle, a housing that houses the torque detecting portion and the rotation angle detecting portion, and a circuit board held by the housing. Both the torque detection magnetic sensors and the rotation angle detection magnetic sensors are mounted on the circuit board.