Gear Shift Assembly with Decoupled Pivot Axes

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Solution Overview

Problem

Traditional manual transmission shifters require flexible joints and a specific size to function effectively, leading to increased costs and space requirements, which hinders compact design and utilization of space for other vehicle components.

Innovation Solution

A gear shift assembly with a shift lever pivoting about two axes, utilizing a gearing mechanism to decouple gear select and shift motions, transmitted through parallel gear racks, allowing for a compact design and reduced space usage by replacing traditional levers with a gearing mechanism and using bevel gears to achieve a 90-degree direction change, enabling smaller gear sizes and reduced material costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional levers with flexible joints are used for gear shift mechanism, then the mechanism can function effectively, but the space required increases and manufacturing cost increases

Engineering Contradiction:
Improvegear shift functionalityVSAvoidspace required for shift mechanism
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces the traditional lever-based mechanical system with a gear-based mechanical system. The shift lever is replaced by gear racks that move linearly, and the pivot joints are replaced by gear teeth engagement. This substitution eliminates the need for flexible joints and reduces the space required for the mechanism while maintaining its functionality.

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

Solution Approach 2:

The patent changes the fundamental parameter of motion transmission from rotational/swinging motion of levers to linear motion of gear racks. By changing the motion type and the mechanism used, the space requirements are reduced and the manufacturing cost is lowered while preserving the gear shift functionality.

Inventive Principle:
Principle #35Parameter changes

2Force

If traditional levers with swinging motion are used, then the mechanism can transmit force, but the size of the shifter must be of a certain length to get a decent lever effect

Engineering Contradiction:
Improveforce transmission capabilityVSAvoidlength of shifter
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

The patent substitutes the lever-based force transmission system with a gear rack and pinion system. Instead of relying on the length of a lever to transmit force, the force is transmitted through the engagement of gear teeth, which can be compact in size. This allows for effective force transmission without requiring a long shifter.

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

3Volume of moving object

If gear mechanism is used to replace traditional levers, then space is reduced, but the complexity of the gearing mechanism increases

Engineering Contradiction:
Improvespace for shift mechanismVSAvoidcomplexity of gearing mechanism
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent segments the gear mechanism into two independent gear racks (first gear rack for select motion, second gear rack for shift motion) that operate separately. This segmentation allows each gear rack to be simple in design while collectively achieving the complex function of gear shifting. The decoupling of motions reduces the overall complexity compared to a single complex lever system.

Inventive Principle:
Principle #1Segmentation

4Volume of moving object

If bevel gears are used to change direction by 90 degrees, then space is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvespace for gear mechanismVSAvoidprecision of bevel gear alignment
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent combines the direction-changing function into the overall gear rack arrangement rather than requiring separate bevel gear assemblies. The first and second gear racks are arranged to move in perpendicular directions, and the bevel gears are integrated into this arrangement, reducing the number of precision alignment points compared to using multiple separate bevel gear stages.

Inventive Principle:
Principle #5Merging (Combining)

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 space needed for the gear shift mechanism, allowing for more compact designs and efficient use of space, while maintaining effective gear select and shift functionality, and reduces material costs by using gear wheel segments instead of full gear wheels.

Implementation Method 1

a first gear, which is arranged rotationally fixed on a first shaft with its axis of rotation aligned with said first pivot axis, such that a select motion of the shift lever turns said first gear, wherein said first gear transmits the select motion of the shift lever to the first gear rack

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

a second gear, which is arranged rotationally fixed on a second shaft with its axis of rotation aligned with said second pivot axis, such that a shift motion of the shift lever turns said second gear, wherein said second gear transmits the shift motion of the shift lever to the second gear rack

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 3

at least one of said first and said second gear or any other gear between said first or second gear and their respective gear rack is a first bevel gear, wherein it is possible to change the direction of the select or shift motion with 90 degrees

Methodology Applied
Scientific EffectBevel gear mechanism: Gear

Data Source

PatentEP2525119B1Gear shift assembly for manual transmission
Publication Date: 2014.12.10 VOLVO CAR CORP
  • EP2525119B1 patent drawingFigure 1
  • EP2525119B1 patent drawingFigure 2a~2c
  • EP2525119B1 patent drawingFigure 3a~3b

AI summary

The object of the present invention is to provide an inventive gear shift assembly (1) for a gear box of an automobile. Said gear shift assembly (1) comprising; a shift lever (2) arranged to pivot about a pivot point (3,103,203) having two pivot axes (4,5), wherein a first pivot axis (4) represents a gear selection axis and a second pivot axis (5) represents a gear shifting axis, and a gear shift pattern that includes at least one gear select gate arranged in a first direction, and at least one gear shift gate arranged in a second direction essentially perpendicular to the gear select gate, wherein a gear shift motion (s) in the direction of a gear shift gate and a gear select motion (v) in the direction of the gear select gate can be performed by pivoting the shift lever (2), the gear select motion (v) and the gear shift motion (s) being decoupled from each other.