Variable Lever Ratio Clutch Actuator Torque Reduction

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Solution Overview

Problem

Existing clutch devices require high torque from actuators to operate pressure members, leading to increased power consumption and potential downsizing challenges.

Innovation Solution

A clutch device with a drive unit that includes an actuator, rotation shafts, and a coupling member, where the lever ratio is adjusted to increase torque efficiency, allowing the pressure member to move from a contact start position to an engagement position with reduced actuator torque, and incorporating a friction member to maintain the engagement position with reduced rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a conventional actuator system is used to operate the pressure member, then the clutch can be engaged and disengaged, but the torque required from the actuator is high, leading to increased power consumption and difficulty in downsizing

Engineering Contradiction:
Improveactuator torqueVSAvoidpower consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The patent applies the dynamics principle by making the lever ratio variable rather than fixed. The lever ratio changes dynamically during the pressure member's movement from disengaged to engaged position, being larger when clutch reaction force is smaller and smaller when clutch reaction force is larger. This dynamic adjustment optimizes torque requirements throughout the operation cycle, reducing peak actuator torque and overall power consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by varying the lever ratio as a controllable parameter. The lever ratio is adjusted based on the clutch reaction force conditions, transitioning between different ratio values to match the operational phase. This parameter optimization allows the actuator to operate more efficiently across different stages of clutch engagement, directly addressing the torque and power consumption issues.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If a conventional actuator system is used to operate the pressure member, then the clutch can be engaged and disengaged, but the actuator size must be large to provide sufficient torque, preventing downsizing

Engineering Contradiction:
Improveactuator sizeVSAvoidactuator torque
Core Design Contradiction:
Volume of moving objectVSPower

Solution Approach 1:

The patent applies the dynamics principle by making the lever ratio variable rather than fixed. The lever ratio changes dynamically during the pressure member's movement from disengaged to engaged position, being larger when clutch reaction force is smaller and smaller when clutch reaction force is larger. This dynamic adjustment optimizes torque requirements throughout the operation cycle, reducing peak actuator torque and overall power consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by varying the lever ratio as a controllable parameter. The lever ratio is adjusted based on the clutch reaction force conditions, transitioning between different ratio values to match the operational phase. This parameter optimization allows the actuator to operate more efficiently across different stages of clutch engagement, directly addressing the torque and power consumption issues.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the pressure member moves from contact start position to engagement position against increasing clutch reaction force, then the clutch engages properly, but the actuator requires excessive torque throughout the entire movement range

Engineering Contradiction:
Improveclutch engagementVSAvoidactuator torque
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent applies the dynamics principle by making the lever ratio variable rather than fixed. The lever ratio changes dynamically during the pressure member's movement from disengaged to engaged position, being larger when clutch reaction force is smaller and smaller when clutch reaction force is larger. This dynamic adjustment optimizes torque requirements throughout the operation cycle, reducing peak actuator torque and overall power consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by varying the lever ratio as a controllable parameter. The lever ratio is adjusted based on the clutch reaction force conditions, transitioning between different ratio values to match the operational phase. This parameter optimization allows the actuator to operate more efficiently across different stages of clutch engagement, directly addressing the torque and power consumption issues.

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

The solution reduces the torque required for the actuator, leading to lower power consumption and the potential for downsizing the actuator, while maintaining efficient clutch engagement and disengagement.

Implementation Method 1

a first member (1Ar, 11Ar) that rotates together with the first rotation shaft around the first rotation shaft

Methodology Applied
Scientific EffectLever: Lever

Implementation Method 2

a second rotation shaft (2S) that rotates together with the movement of the pressure member, a second member (2Ar) that rotates together with the second rotation shaft around the second rotation shaft

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 3

a coupling member (R) that connects, and interlocks, the first member and the second member

Methodology Applied
Scientific EffectGear: Gear

Implementation Method 4

a friction member (34) and a pressure member (33) for pressing the friction member

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2899420B1Clutch device and straddle-type vehicle
Publication Date: 2017.03.15 YAMAHA MOTOR CO LTD
  • EP2899420B1 patent drawingFigure 1
  • EP2899420B1 patent drawingFigure 2
  • EP2899420B1 patent drawingFigure 3

AI summary

When a pressure member of a clutch is placed in an engagement position, a first arm is placed in a first arm position. When the pressure member is placed in a contact start position, the first arm is placed in a second arm position. A reaction force which acts on a actuator from the pressure member is larger in the contact start position than the engagement position. The arm positions are set so that a lever ratio when the first arm is in the second arm position is larger than the lever ratio when the first arm is in the first arm position. Thereby, torque of an actuator necessary for operating the pressure member of the clutch may be made smaller.