Intermediate Plate Press-Fit for EPS Output Shaft Positioning
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Solution Overview
Problem
Existing electric power steering apparatuses face challenges in efficient assembly and long-term performance maintenance, with complex manufacturing processes and potential degradation of torque measuring device precision due to elastic material deterioration.
Innovation Solution
The electric power steering apparatus features an intermediate plate with a circumferentially arranged ridge or projection design, press-fitted into the gear housing using rolling bearings, ensuring secure assembly and maintaining the posture of the output shaft and torque measuring device precision over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If elastic material is used to support the partition plate in existing designs, then assembly is simplified, but positioning precision deteriorates over time due to material deterioration
Solution Approach 1:
The invention extracts and removes the elastic material from the support structure, replacing it with a rigid partition plate supported by rolling bearings. This eliminates the deterioration problem inherent in elastic materials while maintaining assembly simplicity through the press-fit design of the partition plate into the gear housing.
Solution Approach 2:
The invention replaces the deteriorating elastic material with a durable rigid partition plate and rolling bearing assembly. While the initial assembly is slightly more complex, the long-term reliability and maintained positioning precision make it a superior solution that eliminates the need for periodic replacement or adjustment.
2Manufacturing precision
If complex assembly procedures are used to ensure precision, then positioning precision is maintained, but manufacturing efficiency decreases
Solution Approach 1:
The partition plate is designed with a press-fit structure that allows it to be preliminarily positioned and fixed directly into the gear housing during assembly. The rolling bearings are pre-installed on the output shaft, enabling straightforward assembly without complex procedures while maintaining precise positioning of the output shaft and torque measuring device.
3Manufacturing precision
If rigid support structures are used, then positioning precision is maintained, but assembly complexity increases
Solution Approach 1:
The invention merges the partition plate with the rolling bearing support structure, creating an integrated rigid support system. The partition plate is directly pressed into the gear housing with the rolling bearings already in place, combining the positioning and support functions into a single assembly step that maintains precision without increasing overall assembly complexity.
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 design simplifies assembly, enhances manufacturing efficiency, and maintains the performance of the electric power steering apparatus by preventing the degradation of the decelerator engagement and torque measuring device precision even after long-term use.
Implementation Method 1
The output shaft is rotatably supported to the gear housing by rolling bearings
Implementation Method 2
The intermediate plate is press-fitted and fixed in the gear housing
Data Source
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AI summary
An electric power steering apparatus has a first rolling bearing and a second rolling bearing rotatably supporting an output shaft. The first rolling bearing is provided between an inner peripheral surface of a through-hole of a gear housing and an outer peripheral surface of the output shaft. The second rolling bearing is provided between an inner peripheral surface of an intermediate plate press-fitted and fixed in an opening portion of the gear housing and the outer peripheral surface of the output shaft. An outer peripheral portion of the intermediate plate has alternately arranged large diameter portions and small diameter portions, and the large diameter portions are press-fitted in the gear housing.