Power Steering Device Sealed Containment Shell

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Solution Overview

Problem

Current power steering devices are complex and costly to manufacture due to their modular design, with multiple casings that increase the risk of assembly errors and corrosion, particularly from salt spray and galvanic corrosion, leading to reliability issues and increased production defects.

Innovation Solution

A power steering device with a containment shell formed by a base and bell-housing, sealed together to protect the actuator subassembly from external environment, simplifying the design and assembly by separating the actuator subassembly and containment shell, allowing for optimized sealing and material choices without the need for extensive sealing rings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple casings are used to house different functions (assist motor, reducer, torque sensor), then each function can be independently protected and maintained, but the number of sealing rings increases, assembly complexity increases, and the risk of assembly errors and corrosion increases

Engineering Contradiction:

Improveprotection of mechanical membersVSAvoidnumber of casings and sealing rings

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple separate casings (steering casing, reducer casing, motor casing, sensor casing) into a single integrated containment shell. This single shell houses all mechanical members (steering mechanism, assist motor, reducer, torque sensor) without requiring multiple sealing rings at junction interfaces, thereby reducing assembly complexity while maintaining protection reliability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The containment shell serves multiple functions simultaneously: it acts as the steering casing, reducer casing, motor casing, and sensor casing all in one structure. It provides mechanical protection, sealing, and structural support for all components within, eliminating the need for separate specialized casings for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple connections between casings are made to house additional functions, then new functions can be added to improve steering device capabilities, but the likelihood of mounting errors and seal damage increases

Engineering Contradiction:

Improveaddition of new functionsVSAvoidassembly accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

By integrating all functional components into a single containment shell structure, the patent eliminates multiple connection interfaces that could lead to mounting errors. The single-shell design reduces the number of sealing joints from multiple (between separate casings) to minimal (only at the single junction between base and bell-housing), significantly improving assembly precision and reducing defects

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If multiple casings with sealing rings are used to protect mechanical members, then lubrication can be maintained, but the risks of subsequent failure and leakage increase

Engineering Contradiction:

Improvemaintenance of lubricationVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent reduces the number of sealing interfaces from multiple junctions between separate casings to a single junction between the base and bell-housing of the containment shell. Fewer sealing rings mean fewer potential failure points for leakage, thereby extending the service life of the lubrication system and reducing the risk of subsequent failures

Inventive Principle:

Principle #5Merging (Combining)

4Strength

If casings are assembled with metallic fastening screws distinct from the casing material, then secure fastening is achieved, but galvanic corrosion occurs in the presence of water and salt spray

Engineering Contradiction:

Improvefastening strengthVSAvoidgalvanic corrosion

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The containment shell is designed to be formed from a single material (thermoplastic polymer) for both the base and bell-housing portions. This homogeneity eliminates galvanic corrosion by removing dissimilar metal contacts. The single material construction maintains structural strength while being inherently resistant to chemical corrosion from water and salt spray

Inventive Principle:

Principle #33Homogeneity

Data Source

PatentUS10759468B2Power steering device with sealed protective casing

Publication Date: 2020.09.01 JTEKT EUROPE SAS

AI summary

A power-steering device intended to be fitted on a vehicle-receiving structure, such as a cradle, the device including a rack as well as at least one actuator subassembly including at least one assistance motor, one drive gear, as well as one load-bearing structure that carries the assistance motor and is arranged to support and guide the drive gear and the rack relative to one another, the device further including one containment casing that is separate from the actuator subassembly and is fonned by connecting at least one base and one bell housing, which are attached to one another by a sealed joint such that the containment casing prevents the actuator subassembly from being exposed to water splashes, dust and salt spray from the outside environment when the power-steering device is in place on the receiving structure of the vehicle.