Clutch Unit Assist Spring Timing for Wear-Tolerant Disengagement

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Solution Overview

Problem

Existing clutch units face challenges in coping with abrasion of torque transfer members, leading to increased costs and size due to the need for larger actuators and complex control mechanisms to manage the assist force timing, which results in inefficiencies during state transitions between engaged and disengaged states.

Innovation Solution

A clutch unit configuration where the assist force from the auxiliary spring member is input before the clutch reaction force, ensuring the assist force is available during disengagement and not used before engagement, allowing for smooth transitions without the need for large actuators, by adjusting the force transfer path to synchronize assist and reaction forces differently for engaged and disengaged states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the assist force from the auxiliary spring member is input before the clutch reaction force, then smooth disengagement is achieved, but the timing control becomes complex

Engineering Contradiction:
Improvesmooth disengagementVSAvoidtiming control
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The auxiliary spring member is configured to input the assist force before the clutch reaction force during disengagement. This preliminary action ensures that the assist force is available when needed to overcome the clutch spring force, enabling smooth disengagement without complex timing control mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent inverts the conventional force input sequence by having the assist force input before the reaction force, rather than after. This inversion allows the assist force to proactively counteract the clutch spring force during disengagement, simplifying the control mechanism while achieving smooth operation.

Inventive Principle:
Principle #13The other way round (Inversion)

2Speed

If the assist force is available during disengagement, then disengagement speed improves, but actuator size increases

Engineering Contradiction:
Improvedisengagement speedVSAvoidactuator size
Core Design Contradiction:
SpeedVSWeight of moving object

Solution Approach 1:

The auxiliary spring member acts as an intermediary that stores and releases elastic energy to provide assist force during disengagement. This mediator enables high disengagement speed without requiring a large actuator, as the spring supplies additional force during the critical disengagement phase.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The auxiliary spring member provides periodic assist force during the disengagement cycle, energizing at the appropriate moment to accelerate the process. This periodic action allows the actuator to operate at lower power levels while achieving high disengagement speed when needed.

Inventive Principle:
Principle #19Periodic action

3Productivity

If the force transfer path is adjusted to synchronize assist and reaction forces, then transition efficiency improves, but manufacturing complexity increases

Engineering Contradiction:
Improvetransition efficiencyVSAvoidmanufacturing complexity
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent adjusts parameters of the force transfer path, including the positioning and configuration of the auxiliary spring member and its connection points. These parameter changes enable synchronization of assist and reaction forces to improve transition efficiency without significantly increasing manufacturing complexity.

Inventive Principle:
Principle #35Parameter changes

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 enables the clutch unit to efficiently manage abrasion, reducing the need for large actuators and simplifying control, allowing for smooth transitions between engaged and disengaged states while maintaining reduced size and cost.

Implementation Method 1

an auxiliary spring member that inputs an assist force generated by elastic deformation into the transfer member

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3536999B1Clutch unit and vehicle
Publication Date: 2022.04.27 YAMAHA MOTOR CO LTD
  • EP3536999B1 patent drawingFigure 1
  • EP3536999B1 patent drawingFigure 2(A)~2(B)
  • EP3536999B1 patent drawingFigure 3

AI summary

A clutch unit capable of coping with abrasion of a torque transfer member with a configuration different from a configuration of an abrasion compensation device proposed to date. A clutch unit 17 includes a clutch 13 having a clutch spring 28, a motor 50 that generates an actuation driving force for actuating the clutch 13, an output shaft 63 that transfers the clutch reaction force to the clutch 13 and receives an elastic restoring force of the clutch spring 28 as a clutch reaction force, and a spring 71 that inputs an assist force for assisting the actuation driving force to the output shaft 63. In switching the clutch 13 from an engaged state to a disengaged state, the output shaft 63 receives the assist force before receiving the clutch reaction force, whereas in switching the clutch 13 from the disengaged state to the engaged state, the assist force becomes zero after the clutch reaction force becomes zero.