Steering Gear Assembly with Nested Motor and Torsion Tube

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Solution Overview

Problem

Existing hydraulic steering gear assemblies in conventional driver-operated vehicles are difficult and costly to retrofit with electric motors for autonomous or driver-assisted operation, as it requires relocating the steering gear assembly and associated components.

Innovation Solution

A steering gear assembly and remanufacturing kit that replaces the torsion bar with a torsion tube and includes a transfer shaft, allowing an electric or hydraulic motor to be integrated without relocating the steering gear assembly, enabling both manual and motor-driven operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If an electric motor is integrated into a conventional hydraulic steering gear assembly, then autonomous or driver-assisted operation is enabled, but the steering gear assembly must be relocated and output components must be modified

Engineering Contradiction:

Improveautonomous operation capabilityVSAvoidsteering system modification complexity

Core Design Contradiction:

Extent of automationVSDevice complexity

Solution Approach 1:

The patent places the electric motor (120) inside the existing housing (12) of the hydraulic steering gear assembly, nesting it within the available internal space. The motor is positioned around the worm shaft (40) and integrated with the existing ball nut piston (30) mechanism, allowing the motor to drive the steering gear without requiring relocation of the entire assembly or modification of external output components like the Pitman arm (54)

Inventive Principle:

Principle #7Nested doll (Nesting)

2Adaptability or versatility

If the steering gear assembly is relocated to accommodate a motor, then motor integration is achieved, but new steering gear mounts and output components are required

Engineering Contradiction:

Improvemotor integration capabilityVSAvoidremanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent designs the housing (12) to serve multiple functions: it contains the hydraulic steering gear mechanism, accommodates the electric motor (120), and provides mounting structures for both the motor and the existing vehicle chassis. The end cover (114) with rotary seal (116) creates a universal interface that allows the motor shaft to connect to the steering mechanism while maintaining compatibility with original vehicle mounting points, eliminating the need for new steering gear mounts

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Extent of automation

If conventional hydraulic steering gear assemblies are retrofitted with motors, then autonomous operation is enabled, but retrofitting costs and downtime increase

Engineering Contradiction:

Improveautonomous operation capabilityVSAvoidretrofitting ease

Core Design Contradiction:

Extent of automationVSEase of repair

Solution Approach 1:

The patent incorporates the electric motor (120) and its mounting structure into the housing (12) during the remanufacturing process, before the assembly is installed in the vehicle. The motor is pre-positioned and connected to the steering mechanism within the housing, so that when the complete assembly is installed in the vehicle, it functions as a unified unit without requiring additional modification steps at the installation site

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent divides the steering system into separable functional modules: the hydraulic steering gear mechanism, the electric motor (120), and the housing (12) that contains both. This segmentation allows the motor and housing to be manufactured and tested independently, then assembled into a complete unit that can be installed as a single replacement assembly, simplifying the retrofitting process and reducing vehicle downtime

Inventive Principle:

Principle #1Segmentation

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

Enables the economical retrofitting of conventional vehicles with electric or hydraulic motors for autonomous and driver-assisted operation without the need for relocating the steering gear assembly or modifying output components, reducing costs and downtime.

Implementation Method 1

a torsion tube configured to apply a rotational restoring force to the rotatable valve member and the first rotatable input shaft

Methodology Applied

Scientific EffectTorsion: Torsion Spring

Data Source

PatentUS11987299B2Steering gear assembly with multiple input shafts, remanufacturing kit, and remanufacturing methods

Publication Date: 2024.05.21 VOLVO TRUCK CORP

AI summary

A steering gear assembly, which utilizes a manually-drive first rotatable input shaft coupled with a rotatable valve member to control flow of hydraulic fluid to different downstream passages, includes a torsion tube and a transfer shaft extending within the interior of the torsion tube, with the transfer shaft being configured to receive rotational force from a second rotatable input shaft coupled to a motor or another mechanical torque-supplying element. The torsion tube applies a rotational restoring force to the rotatable valve member. A removable end cover for a steering gear assembly housing includes a rotary seal permitting rotation of the transfer shaft and/or second rotatable input shaft, with the first and second rotatable input shafts opposing one another. A remanufacturing kit for a steering gear assembly includes a torsion tube, a transfer shaft, and an end cover as mentioned. A method for remanufacturing a steering gear assembly is further provided.