Steering Shaft Bearing Support With Elastic Radial Deformation

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Solution Overview

Problem

Existing steering devices face challenges in meeting diverse customer demands due to their fixed configurations, leading to increased costs and complexity, particularly in the housing components which are often made of expensive metals like aluminum.

Innovation Solution

A steering device with a cylindrical support tube and a bearing support member that allows elastic deformation, reducing the need for separate metal housing components and enabling easier assembly and reduced component count, while maintaining stability and reducing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional steering device with pinion gear and rack is used, then the steering mechanism is simple in structure, but the pinion gear cannot be disengaged from the rack, causing the steering wheel to remain locked in the central position and unable to return automatically after steering

Engineering Contradiction:
Improveautomatic steering returnVSAvoidsteering mechanism structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The steering mechanism is divided into two independent parts: the pinion gear assembly and the rack assembly. The pinion gear can be selectively engaged or disengaged from the rack through the fourth gear and synchronizing mechanism, allowing independent control of steering lock and return functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection between the pinion gear and rack is made dynamic rather than fixed. The fourth gear and synchronizing mechanism enable the pinion gear to automatically engage with the rack during steering and disengage after steering completion, allowing the steering wheel to return to central position automatically.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the pinion gear is continuously engaged with the rack to maintain steering position, then the steering wheel remains locked, but the steering wheel cannot return to the central position automatically

Engineering Contradiction:
Improvesteering position stabilityVSAvoidsteering wheel return
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The engagement between the pinion gear and rack occurs periodically rather than continuously. The fourth gear and synchronizing mechanism control the pinion gear to engage with the rack only when needed for steering position maintenance, and disengage to allow automatic return to central position.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The steering mechanism uses the existing rotational motion of the fourth gear to automatically drive the pinion gear disengagement and rack retraction, enabling the steering wheel to return to central position without external intervention or additional power source.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If additional components like fourth gear and synchronizing mechanism are added to enable automatic steering return, then automatic steering return is achieved, but the structure becomes more complex

Engineering Contradiction:
Improveautomatic steering returnVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The fourth gear serves multiple functions: it transmits rotational motion from the steering wheel, drives the synchronizing mechanism, and controls the engagement/disengagement of the pinion gear with the rack. The synchronizing mechanism simultaneously coordinates the motion of the pinion gear and rack, ensuring smooth operation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4360997B1Steering device
Publication Date: 2026.05.13 JTEKT CORP
  • EP4360997B1 patent drawingFigure 1
  • EP4360997B1 patent drawingFigure 2
  • EP4360997B1 patent drawingFigure 3

AI summary

A steering device includes a cylindrical support tube (17) that rotatably supports a steering shaft (2), a speed reducer (20) configured to apply a torque to the steering shaft (2), and a housing (18) that includes a cylindrical portion (41) housing the speed reducer (20). A flange (31) of the support tube (17) and the cylindrical portion (41) are disposed coaxially and coupled to each other with a bolt (30). A bearing support member (50) is fitted to an inner peripheral surface of the cylindrical portion (41). The steering shaft (2) extends through the bearing support member (50). A bearing (71) is disposed between an outer peripheral surface of the steering shaft (2) and an inner peripheral surface of the bearing support member (50). The bearing support member (50) includes a deformation allowing portion (55, 56, 59) configured to allow elastic deformation of the bearing support member (50) in a radial direction.