Rotation Angle Sensor Radial Gear Separation Mechanism

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Solution Overview

Problem

The assembly of rotation angle sensors is hindered by interference between the teeth of the driven gears and the main drive gear in the axial direction of the steering shaft, leading to difficulties in inserting the shaft into the sensor housing.

Innovation Solution

A sensor configuration where the driven gears are supported to be rotatable and movable in the radial direction, with a biasing member such as a helical torsion spring and a conversion mechanism to separate the driven gears from the main drive gear during insertion, allowing smooth assembly by converting axial forces into radial forces that move the driven gears away from the main drive gear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the shaft is inserted into the sensor housing with the driven gears supported therein, then the rotation angle sensor can be assembled, but the teeth of the driven gears may interfere with the teeth of the main drive gear in the axial direction, hindering assembly

Engineering Contradiction:

Improveassembly smoothnessVSAvoidinsertion difficulty

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The driven gears are designed to be movable in the radial direction rather than fixed, allowing them to dynamically adjust their position during insertion. The biasing member enables the driven gears to move radially outward when axial insertion force is applied, converting the static support structure into a dynamic one that adapts to the insertion process.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The radial position of the driven gears is changed from a fixed state to a variable state. When axial force is applied during insertion, the driven gears move radially outward, changing their radial coordinate parameter. This parameter change allows the insertion operation to proceed without interference, and after insertion, the driven gears return to their normal meshing position.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the driven gears are fixed in position to ensure proper meshing with the main drive gear, then reliable torque transmission is achieved, but interference during insertion occurs and assembly is hindered

Engineering Contradiction:

Improvemeshing reliabilityVSAvoidassembly difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The biasing member is pre-installed to apply a radial biasing force to the driven gears before insertion. This preliminary action ensures that during the insertion process, the driven gears automatically move outward to avoid interference, and after insertion, they are already in the correct meshing position, eliminating the need for post-assembly adjustment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The biasing member acts as an intermediary between the driven gears and the housing. It mediates the conflict between the need for fixed positioning (for reliable meshing) and the need for movement (for easy insertion). The biasing member allows the driven gears to move during insertion while maintaining their position during operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables smooth assembly of the sensor by avoiding interference between the driven and main drive gears, simplifies the configuration, reduces the number of parts, and allows for the detection of both rotation angle and torque using a single sensor.

Implementation Method 1

a biasing member such as a helical torsion spring and a conversion mechanism to separate the driven gears from the main drive gear during insertion, allowing smooth assembly by converting axial forces into radial forces

Methodology Applied

Scientific EffectHelical torsion spring: Torsion Spring

Implementation Method 2

a biasing member biasing the at least one driven gear toward the main drive gear; and a conversion mechanism configured to convert an axial force that is parallel to an axial direction of the shaft and acts on the at least one driven gear to a force in such a direction that the at least one driven gear is separated from the main drive gear

Methodology Applied

Scientific EffectElastic force: Elasticity

Data Source

PatentUS11193841B2Sensor for smooth assembly

Publication Date: 2021.12.07 JTEKT CORP

AI summary

A sensor includes a main drive gear mounted on a shaft that is subjected to detection by the sensor such that the main drive gear is rotatable integrally with the shaft; at least one driven gear meshing with the main drive gear; a sensor housing accommodating the main drive gear and the at least one driven gear; a biasing member biasing the at least one driven gear toward the main drive gear; and a conversion mechanism configured to convert an axial force that is parallel to an axial direction of the shaft and acts on the at least one driven gear to a force in such a direction that the at least one driven gear is separated from the main drive gear when a part of the at least one driven gear contacts a part of the main drive gear while the shaft is inserted in the sensor housing.