Steering Rotation Limiter With Modular Intermediate Stops

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Solution Overview

Problem

Existing rotation limiting devices for steering wheels, such as those in steer-by-wire systems, are unable to achieve a high degree of freedom in setting the number of lock-to-lock rotations, which is necessary for modern vehicles that require more than two rotations.

Innovation Solution

A rotation limiting device comprising a first member, a second member, and at least one intermediate member, where the intermediate members have radial and axial protrusions that allow for adjustable rotation limits by changing the number of intermediate members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a stopper unit with fixed protrusions is used to limit rotation, then the rotation amount is limited, but the flexibility in setting the number of lock-to-lock rotations is insufficient

Engineering Contradiction:
Improveflexibility in setting rotatable amountVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The rotation limiting device is divided into multiple intermediate members (first, second, third intermediate members) that can be selectively removed. Each intermediate member provides a specific rotation limit when present, allowing the total rotation limit to be adjusted by changing the number of intermediate members in the sequence, thus achieving flexibility without complex adjustment mechanisms

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a fixed rotation limit structure to a dynamic configuration where intermediate members can be added or removed based on requirements. This allows the rotation limit to be dynamically adjusted to achieve different numbers of lock-to-lock rotations (e.g., 2 rotations, 3 rotations, or more) by simply changing the configuration of intermediate members

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the number of intermediate members is increased to allow more rotations, then the rotatable amount increases, but the device complexity increases

Engineering Contradiction:
Improvenumber of lock-to-lock rotationsVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The use of multiple identical or similar intermediate members allows the system to achieve different rotation limits by simply varying the number of segments in the sequence. Each intermediate member has the same basic structure with protrusions and grooves, so adding more members increases the rotation limit without requiring increasingly complex individual components

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each intermediate member is designed with universal functionality to interface with both the steering shaft and the housing. The standardized design of intermediate members allows them to be interchangeably positioned in series, where each member contributes equally to the rotation limit, enabling scalable configuration for different rotation requirements

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

Data Source

PatentEP4570622A1Rotation limiting device and steering device
Publication Date: 2025.06.18 NSK STEERING & CONTROL INC
  • EP4570622A1 patent drawingFigure 1
  • EP4570622A1 patent drawingFigure 2
  • EP4570622A1 patent drawingFigure 3

AI summary

[Problem] A structure capable of improving degrees of freedom in setting the rotatable amount of a rotating member is provided for rotation limiting device. [Solution] The rotation limiting device 4 has a first member 14 having an end axially one-sided protrusion 17, a second member 15 having an end one-sided abutment surface 23 and an end other-sided abutment surface 24, and at least one intermediate member 16 having an intermediate radial protrusion 29 and an intermediate axially one-sided protrusion 30. The intermediate radial protrusion 29 has an intermediate one-sided abutment surface 32 on one side surface in the circumferential direction and an intermediate other-sided abutment surface 33 on the other side surface in the circumferential direction.