Gearbox Switching Device Sliding Sleeve Axial Extensions

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Solution Overview

Problem

Existing shifting devices for transmissions, particularly in motor vehicle transmissions, face challenges in producing internal teeth for sliding sleeves due to increased production effort, and require improved connection mechanisms between idler wheels and shafts without compromising manufacturing efficiency.

Innovation Solution

A switching device is designed to create two switchable, non-rotatable connections between a shaft and a first idler wheel, and between the first and second idler wheels, using a sliding sleeve with axially protruding extensions that pass through openings in the sleeve, allowing for a positive rotational connection without impeding the production of external toothing, and incorporating a synchronizing device for synchronized speed engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If driver elements are connected to the sliding sleeve in a rotationally fixed manner to establish non-rotatable connections, then the connection reliability between shaft and idler wheels is improved, but the manufacturing complexity and cost of the sliding sleeve increases due to internal teeth production

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of connecting the sliding sleeve to the idler wheel directly through internal teeth on the sleeve, the patent inverts the connection approach by using axially protruding extensions on the idler wheel that pass through openings in the sliding sleeve. This reversal of the connection geometry eliminates the need for complex internal teeth while maintaining rotational coupling.

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

Solution Approach 2:

The connection mechanism is segmented into separate functional elements: the sliding sleeve provides axial guidance and positioning, while the axially protruding extensions on the idler wheel provide rotational coupling. This segmentation allows each component to be manufactured independently with simpler processes, avoiding the need for complex internal teeth in the sliding sleeve.

Inventive Principle:
Principle #1Segmentation

2Power

If internal teeth are produced in the sliding sleeve to create non-rotatable connections, then the transmission of rotational force is improved, but the production effort and manufacturing time increase

Engineering Contradiction:
Improverotational force transmissionVSAvoidproduction efficiency
Core Design Contradiction:
PowerVSProductivity

Solution Approach 1:

The patent inverts the traditional approach by placing the toothing features on the idler wheel extensions rather than on the sliding sleeve. This allows rotational force transmission to be achieved through simpler external toothing on the extensions that engage with corresponding features in the sleeve openings, significantly reducing manufacturing complexity and production time.

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

3Strength

If the sliding sleeve is designed with complex internal teeth for driver element connection, then the connection strength between components is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveconnection strengthVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent resolves the contradiction by inverting the connection architecture: instead of complex internal teeth in the sliding sleeve, axially protruding extensions with toothing features on the idler wheel pass through openings in the sleeve. This maintains connection strength through proper toothing engagement while dramatically reducing structural complexity and manufacturing cost.

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

Data Source

PatentEP3457001B1Switching device for gearbox
Publication Date: 2020.12.09 ZF FRIEDRICHSHAFEN AG
  • EP3457001B1 patent drawingFigure 1
  • EP3457001B1 patent drawingFigure 2
  • EP3457001B1 patent drawingFigure 3

AI summary

Switching device (1) for a transmission (G) for establishing a switchable, rotationally fixed connection between a shaft (W) of the transmission (G) and a first loose gear (LR1) associated with the shaft (W), and between the first loose gear (LR1) and a second loose gear (LR2) arranged coaxially to the shaft (W), wherein the switching device (1) has a sliding sleeve (S) arranged between the loose gears (LR1, LR2), wherein the rotationally fixed connection between the shaft (W) and the first loose gear (LR1) can be established by sliding the sliding sleeve (S) in the direction of the first loose gear (LR1), wherein the rotationally fixed connection between the first loose gear (LR1) and the second loose gear (LR2) can be established by sliding the sliding sleeve (S) in the direction of the second loose gear (LR2), wherein the first loose gear (LR1) has a plurality of axially projecting extensions (F) which are connected by openings formed in the sliding sleeve (S). (A) pass through.