Gearbox Selection Actuator Lever for Precise Clutch Engagement

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Solution Overview

Problem

Existing internal control systems for parallel shaft gearboxes face inaccuracies in selection feedback, particularly when clutches are off-center relative to passage fingers, leading to unreliable engagement.

Innovation Solution

A lever mechanism is introduced to drive the interlocking key, fixed by one end to a bidirectionally rotating actuating axis, which mechanically acts on the passage carriage via a ball joint, eliminating the need for a return spring and ensuring precise positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a return spring is used to drive the interlocking key in the opposite direction, then the selection return force is provided, but the positioning precision deteriorates when clutches are off-center relative to shift fingers

Engineering Contradiction:
Improveselection return forceVSAvoidpositioning precision
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The patent replaces the spring-based mechanical system with a bidirectionally rotating actuating shaft system. The actuating shaft, driven by an electric motor through a lever mechanism, provides controlled rotational movement in both directions to position the interlocking key precisely, eliminating the positioning errors caused by spring force variations with off-center clutches.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from passive spring force to active bidirectional rotational control. The actuating shaft can rotate precisely in both directions to positioning marks, allowing the system to compensate for off-center clutch positions and maintain accurate engagement regardless of the clutch position relative to shift fingers.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a solenoid actuated piston is used to rotate the interlocking key, then the selection action is provided, but the system complexity increases

Engineering Contradiction:
Improveselection actionVSAvoidsystem complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the complex solenoid actuated piston mechanism and replaces it with a simpler bidirectionally rotating actuating shaft system. The shaft can be rotated in both directions by a motor to achieve the same selection function, reducing the number of components and simplifying the overall system architecture.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bidirectionally rotating actuating shaft serves multiple functions: it can rotate in both directions to select different gear lines, it provides precise positioning through engagement with positioning marks, and it eliminates the need for separate return spring mechanisms. This multi-functional component reduces overall system complexity while maintaining ease of operation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If the interlocking key is driven by a bidirectionally rotating actuating shaft through a lever mechanism, then the positioning precision is improved, but the device complexity increases

Engineering Contradiction:
Improvepositioning precisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a lever mechanism as an intermediary between the bidirectionally rotating actuating shaft and the interlocking key. This lever, fixed to the shaft, translates the shaft's bidirectional rotation into precise angular positioning of the key, enabling accurate engagement while maintaining a relatively simple mechanical transmission structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3877677B1Internal control selection actuator for a gearbox
Publication Date: 2024.02.14 RENAULT SA
  • EP3877677B1 patent drawingFigure 1A~1B
  • EP3877677B1 patent drawingFigure 2~2B
  • EP3877677B1 patent drawingFigure 3A~4B

AI summary

An internal control selection actuator for a gearbox comprising an interlocking key (6) rotating with a control axis (2) for selecting one of at least two transmission lines by simultaneously locking the unselected lines and rotationally secured to a switching carriage (2), characterised in that the interlocking key (6) is rotated by a lever (11) that is fixed via a first end to an actuation axis (1) rotating in both directions and that mechanically acts on the carriage (2) via its second end.