Manual Transmission Synchronizer Teeth Without Tracking Bevels

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Solution Overview

Problem

Manual transmission synchronizing devices face challenges in minimizing axial overall length, particularly in modern automated transmissions like double clutch transmissions, where existing designs with single-track geometry and tracking bevels lead to increased length and noise issues during shifting.

Innovation Solution

A synchronizing device design that eliminates single-track geometry and tracking bevels, featuring a synchronizing ring with external teeth and flat, perpendicular tooth ends for the clutch and sliding sleeve, allowing for axial movement blocking until speed matching and enabling force-controlled engagement without noise, reducing axial length and noise during shifting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If single-track geometry with inclined surfaces and tapered tooth ends is used, then reliable engagement is achieved, but axial length increases

Engineering Contradiction:
Improveengagement reliabilityVSAvoidaxial length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The invention extracts and eliminates the single-track geometry and tapered tooth ends from the clutch body teeth, retaining only the essential flat end faces for engagement. This removal of unnecessary geometric features directly reduces axial length while preserving the core engagement function through the flat-faced claw tooth design.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using inclined surfaces that taper toward the engagement point, the invention inverts the approach by using flat end faces that are perpendicular to the axial direction. This inversion eliminates the need for axial tapering while maintaining engagement reliability through the flat-faced contact geometry.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If conventional chamfers are used as engagement aids, then axial force conversion is improved, but axial length increases and noise is generated

Engineering Contradiction:
Improveaxial force conversionVSAvoidaxial length
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The invention replaces the mechanical chamfer engagement system with a flat-faced claw tooth system that engages through direct axial contact. This substitution eliminates the need for inclined chamfer surfaces while maintaining effective force transmission through the perpendicular end faces of the claw teeth.

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

Solution Approach 2:

The invention changes the geometric parameters of the tooth ends from inclined chamfers with small angles to flat surfaces perpendicular to the axial direction. This parameter change eliminates axial length consumption while preserving engagement functionality through the modified geometry of the claw tooth ends.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If tracking bevels are provided on tooth ends, then engagement guidance is improved, but axial length increases and shifting noise increases

Engineering Contradiction:
Improveengagement guidanceVSAvoidshifting noise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes the tracking bevels from the tooth ends, retaining only the essential flat end faces for engagement. This elimination of beveled surfaces directly reduces shifting noise while maintaining engagement guidance through the flat-faced geometry of the claw teeth.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the potential harm of noise-generating beveled surfaces into a benefit by using flat end faces that engage silently. The flat-faced geometry provides sufficient engagement guidance without the noise-generating contact of inclined surfaces, turning a harmful feature into a silent engagement system.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 design achieves a shorter axial overall length and minimizes noise during shifting by blocking axial movement until speed adjustment, allowing for efficient engagement without significant noise development, thus optimizing the shifting process in manual transmissions.

Implementation Method 1

the locking surfaces of the sliding sleeve teeth engage with the synchronizer ring teeth as the sliding sleeve is axially displaced. These teeth block further axial movement of the sliding sleeve until the rotational speeds are matched.

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Implementation Method 2

Then, the locking surfaces slide against the inclined surfaces of the synchronizer ring teeth, allowing the synchronizer ring to be reset and the sliding sleeve to engage with the clutch body.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3149350B1Synchronization device and synchronization method
Publication Date: 2021.07.28 HOERBIGER ANTRIEBSTECHNIK HOLDING GMBH
  • EP3149350B1 patent drawingFigure 1~2
  • EP3149350B1 patent drawingFigure 3
  • EP3149350B1 patent drawingFigure 4

AI summary

A synchronization device for a manual transmission has a sliding sleeve (112), which has an inner toothing with a plurality of sliding sleeve teeth (118), and a coupling body of a gear wheel, which has an outer toothing with a plurality of coupling body teeth (120), into which the inner toothing of the sliding sleeve (112) can engage. The invention relates to a synchronization unit which is designed to block an axial movement of the sliding sleeve (112), the coupling body teeth (120) having no oblique meshing portion at the axial tooth end (130) close to the sliding sleeve teeth (118). During shifting, the rotational speed of the sliding sleeve (112) and that of the coupling body are adjusted to each other. An axial force (F) of the sliding sleeve against the coupling body builds up and a rotational speed difference between the sliding sleeve (112) and the coupling body is produced so that the end faces (136, 134) of the sliding sleeve teeth (118) and of the coupling body teeth (120) glide along each other, and the sliding sleeve teeth (118) eventually mesh with the coupling body teeth (120).