Vehicle Reverse Drive Mechanism Friction Damper Heat Wear

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Solution Overview

Problem

The existing reverse drive mechanisms for vehicles suffer from heat generation and wear issues due to large relative rotational speed differences between the reverse drive gear and the friction damper, leading to reduced heat resistance characteristics and durability.

Innovation Solution

Introducing a friction damper between the reverse drive gear and a fixed, non-rotational case, which significantly reduces the relative rotational speed difference, thereby minimizing heat generation and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the friction damper is interposed between the reverse drive gear and the reverse drive exclusive use shaft, then the backlash reducing torque is applied to prevent vibrations and abnormal noise, but the large relative rotational speed difference causes heat generation and wear

Engineering Contradiction:
Improvedurability of friction damperVSAvoidheat generation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent introduces a case as an intermediary element between the reverse drive gear and the friction damper. The case rotates at a speed closer to the reverse drive gear, reducing the relative rotational speed difference. This intermediary structure allows the friction damper to function effectively while minimizing heat generation and wear caused by excessive speed differential.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the rotational speed parameter of the friction damper by mounting it on the case rather than directly on the reverse drive exclusive use shaft. This parameter change reduces the relative rotational speed difference from extremely large values to a manageable level, thereby reducing heat generation and improving durability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the friction damper is interposed between the reverse drive gear and the reverse drive exclusive use shaft, then the backlash reducing torque is applied to prevent vibrations and abnormal noise, but the extremely large relative rotational speed difference leads to wear and reduced heat resistance characteristics

Engineering Contradiction:
Improveheat resistance characteristicsVSAvoidwear of friction damper
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The case serves as a mediator that reduces the harmful effect of large relative rotational speed difference. By mounting the friction damper on the case instead of the reverse drive exclusive use shaft, the relative speed difference is reduced, which directly reduces wear and improves heat resistance characteristics.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful large speed differential into a beneficial configuration where the case's rotation speed acts as an intermediate value. This transformation reduces wear and heat generation while maintaining the backlash reduction function.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If the reverse drive gear is always in geared engagement with the input shaft, then the reverse drive mechanism can function, but the idling rotation of the reverse drive gear causes vibrations and tooth hammering noise due to backlash

Engineering Contradiction:
Improveoperation of reverse drive mechanismVSAvoidvibrations and abnormal noise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent uses the friction damper to generate controlled frictional forces that counteract the harmful vibrations and tooth hammering noise. The friction damper creates a damping effect that reduces the amplitude of unwanted vibrations while maintaining the geared engagement necessary for operation.

Inventive Principle:
Principle #18Mechanical vibration

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 enhances the heat resistance characteristics and durability of the friction damper by reducing the relative rotational speed difference to 2000 rpm, effectively suppressing heat generation and wear, thus improving overall performance.

Implementation Method 1

a friction damper which applies a backlash reducing torque to the reverse drive gear

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3348861B1Reverse drive mechanism of a driving force transmitting device for a vehicle
Publication Date: 2020.11.11 AISIN SEIKI KK
  • EP3348861B1 patent drawingFigure 1
  • EP3348861B1 patent drawingFigure 2
  • EP3348861B1 patent drawingFigure 3

AI summary

The reverse drive mechanism includes a case, drive wheels to which a driving force is transmitted from a driving force source through a transmission, a reverse drive gear which is rotatably connected to an input shaft of the transmission, a reverse drive exclusive use shaft rotatably connected to the drive wheels for supporting the reverse drive gear allowing a relative rotation therewith, when the transmission is in a forward drive speed stage and is connected to the reverse drive gear through a reverse drive establishing mechanism when the transmission is in a reverse drive stage and a friction damper interposed between the reverse drive gear and the case for applying a backlash reducing torque to the reverse drive gear.