Sensor Device Segmentation for Steering Angle Detection
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Solution Overview
Problem
Existing sensor devices for detecting rotation angles of shafts in steering systems require extensive machining and assembly efforts, leading to high manufacturing costs and complexity.
Innovation Solution
A sensor device comprising an external gear, driven gear, rotation angle detection magnet, magnetic sensor, circuit board assembly, and housing members, where the external gear and driven gear mesh, and the magnetic sensor detects the magnetic field of the rotating magnet, with the circuit board assembly mounted on a printed circuit board and housed in separate tubular members, facilitating easier assembly and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the case member is formed of metal to secure support rigidity for the steering shaft, then the support rigidity is improved, but the machining difficulty and manufacturing time increase significantly
Solution Approach 1:
The material parameter of the case member is changed from metal to resin, fundamentally altering the manufacturability while maintaining the required support rigidity through appropriate resin selection and structural design
Solution Approach 2:
The patent adopts a resin case member that is easier and cheaper to manufacture, replacing the durable but difficult-to-machine metal case member, thereby reducing manufacturing costs and time
2Area of stationary object
If the sensor body is made box-shaped to house all components, then the housing capability is improved, but the assembly complexity and manufacturing time increase
Solution Approach 1:
The sensor device is segmented into two separate housing members: a first housing member for the detection gear and a second housing member for the circuit board assembly. This segmentation allows each housing to be simpler in shape and easier to manufacture, while reducing overall assembly complexity through modular design
Solution Approach 2:
The first housing member is positioned inside the second housing member, creating a nested structure that provides housing capability without requiring a complex box-shaped single housing, thereby simplifying manufacturing and assembly
3Ease of manufacture
If the circuit board is inserted and fixed in the box-shaped sensor body, then the component mounting is completed, but the assembly time and labor cost increase
Solution Approach 1:
The circuit board assembly is separated into its own housing (second housing member), allowing it to be pre-assembled and tested independently before final integration, thereby reducing the time required for assembly operations
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
The design allows for easier machining and assembly of the sensor device, reducing manufacturing costs and improving the efficiency of the sensor's installation process while maintaining accurate rotation angle detection.
Implementation Method 1
The rotation angle detection permanent magnet is configured to rotate together with the driven gear. The rotation angle detection magnetic sensor is configured to detect a magnetic field of the rotation angle detection permanent magnet.
Data Source
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AI summary
Provided is a sensor device that is machinable and mountable easily, whereby the manufacturing cost can be reduced. A sensor device (6) includes an external gear (645) configured to rotate together with a pinion shaft (23), driven gears (66, 67) configured to rotate by meshing with the external gear (645), permanent magnets (68, 69) configured to rotate together with the driven gears (66, 67), magnetic sensors (621, 622) configured to detect magnetic fields of the permanent magnets (68, 69), a circuit board assembly (62) having the magnetic sensors (621, 622) mounted on a printed circuit board (620), a tubular first housing member (7) that houses the external gear (645), and a second housing member (8) that supports the driven gears (66, 67) and houses the circuit board assembly (62). The second housing member (8) has a flange portion (81) that abuts against an open end face (740a) of a fitting hole (740) of the first housing member (7), and parts of the driven gears (66, 67) that protrude from the flange portion (81) mesh with the external gear (645) inside the first housing member (7).