Gearbox Synchronizer Spring Ring Radial Nesting

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Solution Overview

Problem

Modern manual transmissions face challenges in achieving a compact synchronization unit design, particularly in the axial direction, while maintaining strength and torque transmission capabilities.

Innovation Solution

A synchronization unit with a hub having continuous external teeth, a sliding sleeve that can be axially displaced but rotationally fixed in the circumferential direction, and a spring ring that acts as a pre-synchronizing element to lock the sliding sleeve in a neutral position, allowing for a more compact and robust design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the hub has interrupted external teeth to accommodate pressure pieces, then the axial space is reduced, but the strength of the hub and torque-transmitting capacity are compromised

Engineering Contradiction:
Improveaxial spaceVSAvoidhub strength and torque-transmitting capacity
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The spring ring is positioned radially inside the hub's external teeth rather than axially behind them. This radial positioning allows the hub to have continuous external teeth in the axial direction, maintaining both strength and torque capacity while achieving compact axial dimensions through three-dimensional spatial optimization.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The spring ring is nested within the hub structure, positioned radially inside the external teeth. This nesting arrangement allows the spring ring to function as a pre-synchronizing element without requiring the hub to have interrupted teeth, thereby maintaining hub integrity and torque-transmitting capacity while achieving compact axial design.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If pressure pieces are used to press the synchronizer ring against the friction surface, then synchronization is achieved, but the axial dimensions increase

Engineering Contradiction:
Improvesynchronization functionVSAvoidaxial dimensions
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The spring ring operates in the radial dimension rather than the axial dimension. By positioning the spring ring radially inside the hub's external teeth, the pre-synchronizing function is achieved without increasing axial dimensions, as the spring ring applies force radially inward on the synchronizer ring rather than axially from behind.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The spring ring acts as an intermediary element between the hub and the synchronizer ring. It is arranged radially inside the hub's external teeth and engages the synchronizer ring to provide pre-synchronization, serving as a compact mediator that eliminates the need for axial pressure pieces.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If the spring ring is made of wire, then it provides spring properties, but the axial dimensions are larger compared to formed sheet metal

Engineering Contradiction:
Improvespring propertiesVSAvoidaxial dimensions
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The spring ring is manufactured from formed sheet metal instead of wire, representing a change in material form and manufacturing parameters. This parameter change enables the spring ring to achieve the required spring properties and strength while occupying significantly less axial space, as sheet metal can be formed into a compact, thin-walled structure that provides elastic compliance in the radial direction.

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 a compact axial design with enhanced torque transmission capabilities and ease of assembly, while maintaining effective synchronization and gear engagement processes.

Implementation Method 1

a spring ring (22, 24) that is arranged on an axial side of the external toothing of the hub and is configured to lock the sliding sleeve (16) in a neutral position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

at least one synchronizer ring (70) that has a preferably conical friction surface for frictional coupling of the synchronizer ring (70) with a gear (3, 4) of the manual transmission

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3312446B1Synchronizing unit for a gearbox and gearbox
Publication Date: 2020.12.16 HOERBIGER ANTRIEBSTECHNIK HOLDING GMBH
  • EP3312446B1 patent drawingFigure 1~2
  • EP3312446B1 patent drawingFigure 3
  • EP3312446B1 patent drawingFigure 4~5

AI summary

The invention relates to a synchronization unit for a manual transmission, in particular of a motor vehicle, comprising a hub (10) which can be connected to a transmission shaft (2) in a rotationally fixed manner and which has a circumferentially continuous external toothing (14), a sliding sleeve (16) which is axially displaceable on the external toothing (14) of the hub (10) but is coupled in a rotationally fixed manner in the circumferential direction, and at least one synchronization ring (50, 54;70), which has a preferably conical friction surface for friction coupling of the synchronizer ring with a gear (3, 4) of the transmission and is actuated by the sliding sleeve (16), and a spring ring (22, 24) which is arranged on an axial side of the external toothing (14) of the hub (10) and is configured to lock the sliding sleeve (16) in a neutral position, wherein the spring ring (22, 24) bears against an end face (40) of the sliding sleeve (16) and is effectively arranged between the sliding sleeve (16) and the synchronizer ring (50, 54; 70). The invention also relates to a transmission for a vehicle with at least one synchronizer unit (10, 16, 22, 24) of this type.