Steering Reducer Damping Coupler Vibration Control

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Solution Overview

Problem

Conventional electric power-assisted steering apparatuses experience vibration and noise issues when the worm shaft and motor shaft perform forward/reverse rotations, leading to rattle noise and slip, which negatively impact the driver's steering experience.

Innovation Solution

A reducer design that includes a worm shaft meshing with a worm wheel, a worm shaft bush coupled to the motor shaft, and a connection member that absorbs vibration and noise by using damping members and rolling members to prevent slip between the worm shaft and motor shaft, ensuring coaxial torque delivery and reducing rattle noise and vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a conventional reducer structure with worm shaft and motor shaft is used, then torque transmission is achieved, but vibration and noise occur during forward/reverse rotation

Engineering Contradiction:

Improvetorque transmissionVSAvoidvibration and noise

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

A damping coupler is introduced as an intermediary component between the worm shaft and motor shaft. This coupler contains damping members that absorb vibration and noise while still allowing torque transmission, thus resolving the contradiction between power transmission and harmful vibrations.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The damping coupler utilizes composite material structure combining rigid elements for torque transmission and damping materials for vibration absorption. This composite approach allows simultaneous achievement of power transmission and vibration reduction.

Inventive Principle:

Principle #40Composite materials

2Productivity

If the worm shaft and motor shaft are directly connected, then torque delivery is efficient, but slip occurs between the shafts

Engineering Contradiction:

Improvetorque delivery efficiencyVSAvoidslip prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The damping coupler serves as a mediator that maintains reliable connection between worm shaft and motor shaft. It prevents slip through its structural design while still allowing efficient torque delivery, thus resolving the contradiction between productivity and reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The damping coupler employs flexible damping members that can deform elastically to accommodate minor misalignments and prevent slip, while maintaining continuous torque transmission. This flexibility ensures both efficient power delivery and reliable connection.

Inventive Principle:

Principle #30Flexible shells and thin films

3Stability of the object's composition

If rigid connection between worm shaft and motor shaft is used, then torque transmission is stable, but rattle noise increases

Engineering Contradiction:

Improvetorque transmission stabilityVSAvoidrattle noise

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The damping coupler acts as an intermediary that decouples the rigid connection between worm shaft and motor shaft. It maintains stable torque transmission through its structural design while absorbing rattle noise through damping members, thus resolving the contradiction between stability and noise reduction.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The damping members in the coupler are positioned beforehand to cushion against potential rattle noise and vibrations. This preventive cushioning approach allows stable torque transmission while eliminating rattle noise before it can propagate.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 solution effectively absorbs vibration and noise, preventing slip and improving the driver's steering feel by reducing rattle noise and vibration between the worm shaft and motor shaft during forward/reverse rotations.

Implementation Method 1

a damping coupler configured to be coupled to an outer periphery of an end of the worm shaft, which is coupled with the motor shaft

Methodology Applied

Scientific EffectDamping: Damping

Implementation Method 2

a connection member configured to be coupled to an outer periphery of the damping coupler at one side, and to be coupled to an outer periphery of the motor shaft at the other side

Methodology Applied

Scientific EffectRolling: Roller

Data Source

PatentUS9897148B2Reducer of electric power-assisted steering apparatus

Publication Date: 2018.02.20 HL MANDO CORP

AI summary

The present invention relates to a reducer of an electric power-assisted steering apparatus. An embodiment of the present invention provides a reducer that includes: a worm shaft configured to mesh with a worm wheel; a worm shaft bush configured to be coupled to an outer periphery of an end of the worm shaft to be coupled with a motor shaft among opposite ends of the worm shaft; and a connection member configured to be coupled to an outer periphery of the worm shaft bush at one side thereof, and to be coupled to an outer periphery of the motor shaft at the other side thereof such that a torque of the motor shaft is coaxially delivered to the worm shaft.