Steering Assist Speed Reducer With Single-Line Torque Output

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional steering assistance devices output two lines of torque to the rack shaft, leading to a larger device size due to the dual torque inputs from the driver and the motor, which complicates downsizing efforts.

Innovation Solution

A two-stage speed reducer system with a crank shaft and oscillating gear configuration that receives the driver's operation force, transmitting it through a single line of output to the steering mechanism, utilizing a motor fixed to the output shaft and incorporating bevel gears, idler gears, and a speed-increasing gear to achieve a single line of final output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a pinion is mounted to the final output shaft of the speed reducer and meshes with a rack shaft, then the steering assistance force can be transmitted to the steering mechanism, but two lines of large torques are outputted to the rack shaft (one from the motor through the speed reducer and one directly from the driver), leading to a larger device size

Engineering Contradiction:
Improvesteering assistance forceVSAvoiddevice size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The patent merges the motor-driven assistance force and the driver's operation force into a single transmission line. The speed reducer receives both the motor's driving force and the driver's operation force as inputs, and outputs a single combined torque to the rack shaft, eliminating the need for two separate torque transmission paths and reducing device size.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The speed reducer is designed to perform multiple functions: it reduces the motor's driving force to an appropriate level, transmits the driver's operation force, and combines both forces into a single output. This multi-functionality allows a single component to handle what would traditionally require separate transmission paths.

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

2Ease of operation

If a conventional speed reducer configuration is used with separate input paths for motor and driver forces, then the steering assistance can be provided, but the device complexity increases due to multiple torque input lines

Engineering Contradiction:
Improvesteering assistanceVSAvoidnumber of torque input lines
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines multiple input forces (motor driving force and driver operation force) into a single speed reducer unit that processes both inputs and produces a single output. This merging reduces the number of separate torque input lines and simplifies the overall device structure while maintaining steering assistance functionality.

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

This configuration allows for downsizing of the steering assistance device by ensuring a single line of final output from the speed reducer, enhancing operational efficiency and reducing the device's overall size while maintaining assistive steering capabilities.

Implementation Method 1

the speed reducer comprises a crank shaft and an oscillating gear

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

a first bevel gear disposed on the first rotation shaft; and a second bevel gear meshing with the first bevel gear

Methodology Applied
Scientific EffectBevel gear transmission: Gear

Implementation Method 3

the speed reducer is configured to decelerate a driving force from a motor and output the decelerated driving force

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP3492776B1Assistance device
Publication Date: 2021.05.12 NABTESCO CORP
  • EP3492776B1 patent drawingFigure 1
  • EP3492776B1 patent drawingFigure 2
  • EP3492776B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide a steering assistance device (30) that has a single line of final output, thereby to achieve downsizing. The assistance device (30) of the present application includes a speed reducer (32) configured to decelerate a driving force from a motor (31) and output the decelerated driving force, wherein the speed reducer (32) is configured to receive an operation force produced by an operation of a human.