Automotive Shifting Device Locking Mechanism Design

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Solution Overview

Problem

Manual gear shifting in vehicles often results in incorrect engagement of shift rails, leading to mismatched speed and direction of rotation, potentially causing unexpected driving situations or damage due to the complexity and cost of existing locking systems.

Innovation Solution

A simplified locking device with a locking section and guide section arranged on the same side of the selector shaft, allowing axial displacement for preselection and decoupling during pivoting, enabling precise gear engagement while being cost-effective and easy to manufacture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking device is arranged between the selector shaft and manual transmission to prevent incorrect gear engagement, then the reliability of gear selection is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvereliability of gear selectionVSAvoidcomplexity of locking system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking device is segmented into two distinct functional sections: a locking section with locking fingers that engage with notches on shift rails to prevent diagonal shifting, and a guide section with guide fingers that guide the selector shaft during axial displacement. This segmentation allows each section to perform its specific function independently, improving reliability while keeping the overall structure manageable and manufacturable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking device serves multiple functions simultaneously: it locks non-selected shift rails during preselection, guides the selector shaft axially, and releases the selected shift rail. By combining these functions into a single integrated component rather than separate mechanisms, the patent reduces device complexity while maintaining high reliability of gear selection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If a locking system with multiple components is used to ensure precise gear engagement, then the manufacturing precision is improved, but the ease of manufacture deteriorates

Engineering Contradiction:
Improveprecision of gear engagementVSAvoidease of manufacture of locking system
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The locking section and guide section are merged into a single locking device component that is carried along with the selector shaft. This merging reduces the number of separate parts that need to be manufactured and assembled, improving ease of manufacture while maintaining precise gear engagement through the carefully designed geometry of the locking and guide fingers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Different sections of the locking device have specialized local geometries optimized for their specific functions: the locking fingers have notch engagement surfaces for precise positioning, while the guide fingers have smooth surfaces for guiding axial movement. This local optimization ensures high manufacturing precision for gear engagement without requiring the entire component to be equally complex.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the locking device is carried along with axial displacement of the selector shaft, then the ease of operation is improved, but the device complexity increases

Engineering Contradiction:
Improveease of gear preselectionVSAvoidcomplexity of coupling mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The coupling between the locking device and selector shaft is dynamic rather than rigid: the locking device is carried along during axial displacement for preselection but is decoupled during pivoting for gear shifting. This dynamic behavior is achieved through the geometric relationship between the locking fingers and shift rail notches, which naturally engage during axial movement but disengage during rotation, simplifying the overall mechanism.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2179200B1Shifting device for a transmission of a motor vehicle having a locking device
Publication Date: 2011.09.14 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP2179200B1 patent drawingFigure 1
  • EP2179200B1 patent drawingFigure 2
  • EP2179200B1 patent drawingFigure 3

AI summary

The invention is based on the aim of providing a shifting device having a locking device for locking shifting rails for a transmission of motor vehicles, the device being safe to operate and cost-effective. The invention provides a shifting device (1) for a transmission of a motor vehicle having a locking device (11), comprising a selector shaft (2) for the preselection and shifting of gears in the transmission, and having a plurality of shifting rails (9) a, b, c, d for transmitting the shifting torques from the selector shaft (2) to the transmission, wherein the selector shaft (2) is aligned perpendicular to the shifting rails (9) a, b, c, d, and is axially (3) displaceable for the preselection of gears and is disposed pivotally (4) about the own axis thereof for shifting gears, wherein the locking device (11) has a locking section (12) for releasing one of the shifting rails (9) a, b, c, d and for locking the other shifting rails and a guide section (15) for axially guiding the locking device (11) to a guide member fixed on the housing, wherein the locking device (11) is configured and/or disposed such that it is carried along upon an axial displacement (3) of the selector shaft (2) for the preselection of the gears, and runs freely upon a pivoting (4) of the selector shaft for shifting the gears, wherein the locking section (12) is configured as a first planar sheet metal section defining a locking plane in the planar extension, and wherein a guide plane is defined as a displacement plane between the guide section (15) and the guide member, wherein the locking plane and the guide plane are arranged parallel to each other on the same side of the selector shaft (2).