Dog Clutch Transmission Torque Control

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Solution Overview

Problem

Existing speed change control devices experience delays in driving force recovery after a speed change due to synchronization issues, leading to reduced vehicle acceleration.

Innovation Solution

A vehicle equipped with a dog clutch-type speed change device that includes a clutch in a partially connected state to transmit torque from a motive power source to a drive shaft, utilizing a clutch actuator and motive power source-torque adjustment device to control the engagement and torque levels, ensuring higher acceleration after the completion of gear engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the engine torque is increased after completion of the engagement between the sleeve and the idling gear, then the driving force is delayed in rising, but if the engine torque is increased before completion of engagement, then the engagement process becomes unstable

Engineering Contradiction:
Improvedriving force rise speedVSAvoidengagement stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent applies preliminary action by increasing the engine torque before the completion of engagement between the driving dog and driven dog. Specifically, the engine torque is increased while the sleeve is still in the process of engaging with the idling gear, so that the high torque is already available immediately after engagement completes, eliminating the delay in driving force rise.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses dynamics by transitioning the clutch from a fully connected state to a partially connected state during the engagement process. The clutch is partially disconnected while the driving dog moves toward the driven dog, then re-connected after engagement, allowing dynamic control of torque transmission throughout the speed change process.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the clutch is put in a partially connected state and engine torque is increased before engagement completion, then the driving force rises rapidly after engagement, but the torque transmission during engagement becomes complex

Engineering Contradiction:
Improveacceleration performanceVSAvoidtorque transmission control complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the clutch connection state into distinct phases: fully connected state before engagement, partially connected state during engagement, and fully connected state after engagement. This segmentation allows independent optimization of torque control for each phase, simplifying the overall control strategy despite the complex torque transmission requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses parameter changes by dynamically adjusting the clutch connection state (from fully connected to partially connected and back) and the engine torque level (increased before engagement, maintained during engagement, then further increased after engagement). These parameter changes enable precise control of torque transmission to achieve rapid acceleration while managing engagement 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

The solution enables early and rapid increase in driving force post-engagement by maintaining a partially connected clutch state and increasing motive power source torque, resulting in enhanced vehicle acceleration.

Implementation Method 1

a clutch that is configured to, in a fully connected state, transmit a torque from a motive power source to a main shaft as a clutch friction member is pressed

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4446622B1vehicle
Publication Date: 2026.04.01 YAMAHA MOTOR CO LTD
  • EP4446622B1 patent drawingFigure 1(a)~1(f)
  • EP4446622B1 patent drawingFigure 2
  • EP4446622B1 patent drawingFigure 3

AI summary

In a vehicle (1) equipped with a speed change control device (50) of a dog clutch-type automatic transmission including a clutch actuator (60) that controls a clutch (44), a transmission (48) that performs a speed change by gears, a motive power source-torque adjustment device (80) that adjusts a torque of a motive power source (45) when a speed change is performed, and a control device (90) that controls the clutch actuator (60) and the motive power source-torque adjustment device (80), when changing a speed, the control device (90) controls the clutch actuator (60) so as to put the clutch (44) in a partially connected state and controls the motive power source-torque adjustment device (80) so as to increase the torque of the motive power source (45), while a driving dog is moving toward a driven dog, such that a front-rear acceleration higher than a front-rear acceleration at the time of generation of a speed change command occurs immediately after engagement.