Steering Gear Sensor Housing With C-Shaped Clamping Element

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Solution Overview

Problem

The assembly of steering gears for electric or electrohydraulic power steering systems without a hydraulic servo valve is complex and poses a risk of damaging sensors due to the large diameter of torque and angle sensors, making it difficult to clamp the fixed bearing against the housing.

Innovation Solution

A slotted C-shaped clamping element is used, which can be retrofitted with ease and includes a receptacle for the outer ring of the fixed bearing, along with a multi-part sensor housing featuring an adapter and end cap for correct positioning and protection, allowing for standardized assembly and sensor orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor with large outer diameter is used to detect steering torque and steering angle, then the sensor can accurately measure the required parameters, but the outer ring of the roller bearing serving as a fixed bearing can no longer be clamped against the housing of the steering gear

Engineering Contradiction:
Improvesteering torque detection accuracyVSAvoidassembly ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

A clamping element is introduced as an intermediary component between the fixed bearing and the sensor housing. This clamping element has a C-shaped cross-section with a receptacle for the outer ring of the fixed bearing, allowing it to be clamped against the sensor housing without directly contacting the sensor. This mediator enables the assembly of large-diameter sensors while maintaining the clamping mechanism for the fixed bearing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sensor housing is divided into multiple parts: the main sensor housing, an adapter, and an end cap. This segmentation allows the clamping element to be positioned between the fixed bearing and the end cap, creating space for both the large-diameter sensor and the bearing clamping mechanism to coexist without interference.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If an intermediate element is used to extend outwards over the sensor circumference to enable fixed bearing attachment, then the assembly concept is retained, but the assembly of the clamping element becomes very complex

Engineering Contradiction:
Improveassembly concept compatibilityVSAvoidclamping element assembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The clamping element is designed with a C-shaped cross-section that provides multiple functions: it clamps the fixed bearing, contacts the sensor housing, and can be retrofitted with a clamping ring. This multi-functional design simplifies the overall assembly process while maintaining compatibility with existing assembly concepts.

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

Solution Approach 2:

The clamping element is designed as a simple, easily manufacturable component that can be quickly assembled and disassembled. The C-shaped design allows for simple fabrication and easy installation, reducing assembly complexity compared to more complex intermediate elements.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If a clamping element is arranged between the fixed bearing and the sensor, then the fixed bearing can be clamped, but there is a risk that the clamping element will damage the sensor when the input shaft is being transported prior to assembly

Engineering Contradiction:
Improvefixed bearing clamping forceVSAvoidsensor damage risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The clamping element acts as a mediator that distributes the clamping force from the fixed bearing over a larger area of the sensor housing, rather than concentrating it at a single point. This reduces the risk of damaging the sensor during transport and assembly while still providing sufficient clamping force to secure the bearing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The C-shaped cross-section of the clamping element provides a degree of flexibility that allows it to conform to the sensor housing surface, distributing pressure evenly and reducing the risk of localized damage to the sensor during handling and transport.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP2093127B1Steering gear with sensor
Publication Date: 2011.04.13 ZF AUTOMOTIVE GERMANY GMBH
  • EP2093127B1 patent drawingFigure 1~2
  • EP2093127B1 patent drawingFigure 3
  • EP2093127B1 patent drawingFigure 4

AI summary

The gear has a housing (10), and an input shaft (12) comprising a pinion (14). A sensor (22) is arranged on the input shaft. A fixed bearing (20) is arranged between the sensor and the pinion. A sensor housing (24) surrounds the sensor. The sensor housing rests against a C-shaped clamping element (40) i.e. slotted disk. The clamping element pressurizes the fixed bearing against the housing. The clamping element comprises a retainer for an outer ring of the fixed bearing. A center ring is arranged between an end cap made of plastic and an adapter of the sensor housing.