Sliding Differential Gear Mounting for Self-Centering Mesh

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Solution Overview

Problem

Conventional differential gears face issues with friction and misalignment due to tight tolerances and rigid mounting, which affect their performance and maneuverability, especially in urban delivery vehicles like cargo bikes where space constraints and varying loads are common.

Innovation Solution

A differential gear design featuring a cantilever mounting system with sliding blocks and slideways allows the differential gears to self-center, reducing friction and accommodating coarser manufacturing and assembly tolerances, enabling better running properties and stress distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If differential gears are rigidly mounted with tight tolerances, then positioning precision is improved, but friction increases and manufacturing complexity increases

Engineering Contradiction:
Improvepositioning precisionVSAvoidfriction
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The differential gear is mounted on a cam follower that can dynamically adjust its position within a slide track, transforming the rigid static mounting into a dynamic adaptive system. The cam follower moves freely within the axial play of the slide track, allowing the differential gear to self-center and reduce friction contacts with the housing while maintaining proper meshing engagement.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If tight tolerances are used in differential gear components, then positioning accuracy is improved, but manufacturing difficulty increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidmanufacturing difficulty
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The differential gear system performs self-alignment through the cam follower mechanism within the slide track. The forces from gear meshing automatically position the differential gear in the optimal location, eliminating the need for precise pre-positioning during manufacturing. This self-centering capability allows the use of coarser tolerances while maintaining proper gear engagement and performance.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If differential gears are rigidly fixed in position, then structural stability is improved, but running properties deteriorate due to friction and misalignment

Engineering Contradiction:
Improvestructural stabilityVSAvoidrunning properties
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The system transitions from a static rigid mounting to a dynamic adjustable mounting where the cam follower can move within the slide track. This dynamic capability allows the differential gear to adapt its position during operation, reducing friction and improving running properties while the slide track provides structural guidance and stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mounting system allows changes in the positional parameters of the differential gear during operation. The cam follower can shift its position within the axial play range, enabling the differential gear to optimize its location for reduced friction and improved meshing engagement, thereby enhancing running properties without compromising structural integrity.

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 improves the running properties of the differential gear by allowing self-centering and reducing friction, enabling better performance and stability even with coarser tolerances, and extends the lifespan of components through reduced wear.

Implementation Method 1

a differential gear typically contacts a differential housing, resulting in friction, particularly between a pin of the differential gear and the housing

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4141289A1Differential transmission for a vehicle
Publication Date: 2023.03.01 HIRSCHVOGEL HLDG GMBH
  • EP4141289A1 patent drawingFigure 1~2
  • EP4141289A1 patent drawingFigure 3~4
  • EP4141289A1 patent drawingFigure 5~6

AI summary

The present invention relates to a differential gear (1) for a vehicle. The differential gear (1) comprises a housing (2) with at least one sliding track (20), a first axle shaft gear (4) with a first axle shaft gear toothing (5), a second axle shaft gear (6) with a second axle shaft gear toothing (7), and at least one differential gear (8, 9) with differential gear toothing (11, 16). The differential gear (8, 9) is arranged between the first axle shaft gear (4) and the second axle shaft gear (6), the differential gear toothing (11, 16) being in engagement with the first axle shaft gear toothing (5) and with the second axle shaft gear toothing (7). The first axle shaft gear toothing (5) exerts a first displacement force (F1) on the compensating gear toothing (11, 16), and the second axle shaft gear toothing (7) exerts a second displacement force (F2) on the compensating gear toothing (11, 16).The compensating gear (8, 9) is slidably mounted in the slide (20) so that it can move between the first axle shaft gear (4) and the second axle shaft gear (6). The compensating gear (8, 9) is moved into an equilibrium position between the first axle shaft gear (4) and the second axle shaft gear (6) by the first displacement force (F1) and the second displacement force (F2).