Steering Angle Sensor Gear Stop for Multi-Turn Detection

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Solution Overview

Problem

Existing steering systems for vehicles with rotary angle sensor arrangements are complex and lack efficient mechanisms to prevent over-rotation of the steering wheel and simplify construction while effectively detecting multiple rotations.

Innovation Solution

A steering system with a steering wheel actuator connected to a control system via an external rotor electric motor, incorporating a rotary angle sensor arrangement that includes a rotary angle encoder and sensor to detect rotational angles within a range of less than +/- 360°, utilizing a gearbox as a fixed mechanical stop and enabling detection of partial and multiple rotations, and compensating for asymmetries using a lookup table.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid steering column with traditional rotary angle sensor arrangement is used, then the steering system structure is simple, but it cannot prevent over-rotation of the steering wheel and lacks efficient detection capability for multiple rotations

Engineering Contradiction:
Improveprevention of over-rotationVSAvoidsteering system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the mechanical stop function with the rotary angle sensor arrangement by integrating the gear unit into the steering column structure. The first gear part on the shaft and second gear part on the rotation encoder are merged with the sensor assembly, creating a unified structure that prevents over-rotation while enabling multiple rotation detection without adding separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The gear unit serves multiple functions simultaneously: it acts as a mechanical stop to prevent over-rotation, serves as a transmission mechanism for the rotary angle sensor, and enables detection of multiple rotations. This multi-functionality resolves the contradiction by achieving reliability improvements without proportionally increasing device complexity.

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

2Measurement precision

If separate mechanical stops and rotary angle sensors are used, then over-rotation prevention and rotation detection are reliable, but the construction becomes complex and space-consuming

Engineering Contradiction:
Improverotational angle detectionVSAvoidcomponent quantity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the mechanical stop function with the rotary angle sensor arrangement by integrating the gear unit into the steering column structure. The first gear part on the shaft and second gear part on the rotation encoder are merged with the sensor assembly, creating a unified structure that prevents over-rotation while enabling multiple rotation detection without adding separate components.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the steering wheel actuator with external rotor electric motor is added, then multiple rotations can be detected and asymmetries compensated, but the device complexity increases

Engineering Contradiction:
Improvedetection capabilityVSAvoidactuator system structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The external rotor electric motor serves multiple functions: it acts as the steering wheel actuator, provides a mechanical reference point for asymmetry compensation, and enables detection of multiple rotations through the gear unit. The control system uses the motor's rotational position to compensate for asymmetries in the steering system, achieving enhanced adaptability without proportionally increasing complexity.

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

4Ease of manufacture

If the gearbox serves as both mechanical stop and rotation detector, then space and components are saved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveconstruction simplificationVSAvoidgear unit tolerance
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent combines the mechanical stop function with the rotary angle sensor arrangement by integrating the gear unit into the steering column structure. The first gear part on the shaft and second gear part on the rotation encoder are merged with the sensor assembly, creating a unified structure that prevents over-rotation while enabling multiple rotation detection without adding separate components.

Inventive Principle:
Principle #5Merging (Combining)

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 system simplifies construction, prevents over-rotation, and enhances detection capabilities, allowing for a space-saving and component-efficient design suitable for vehicles requiring multiple steering wheel rotations.

Implementation Method 1

the steering wheel actuator, which is connected to the control system for signal transmission and has an external rotor electric motor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a rotary angle sensor arrangement (6), which is connected to the control unit for signal transmission, for determining a rotational angle of the shaft (8)

Methodology Applied
Scientific EffectElectromagnetic field detection: Electromagnetic Induction

Data Source

PatentEP4294700B1Rotational angle sensor assembly and steering system for a vehicle
Publication Date: 2026.01.21 HELLA GMBH & CO KGAA
  • EP4294700B1 patent drawingFigure 1

AI summary

The present invention relates to a rotational angle sensor assembly (6) for determining a rotational angle of a shaft (8) during rotation of the shaft (8) about an axis of rotation (10) of the shaft (8), comprising a rotation indicating element (12), which is force-transmittingly connected to the shaft (8), and a rotation sensor (14) for detecting motion of the rotation indicating element (12), characterized in that a first transmission-mechanism part (16) of a transmission mechanism (18) of the rotational angle sensor assembly (6) is disposed on the shaft (8), the first transmission-mechanism part being disposed for conjoint rotation, and the rotation indicating element (12) is a second transmission-mechanism part of the transmission mechanism (18), the second transmission-mechanism part being in engagement with the first transmission-mechanism part (16), the transmission mechanism (18) simultaneously forming a fixed mechanical stop of the shaft (8) at each of a first end of a rotational angle range of the shaft (8), for counterclockwise rotation of the shaft (8), and a second end of the rotational angle range of the shaft (8), for clockwise rotation of the shaft (8).