Shift Drive Rack Structure for Long Stroke in Compact Gearboxes

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Solution Overview

Problem

Existing electronic shift drivers are limited to providing external force for P gear and cannot be expanded to automatically handle R, N, and D gears, restricting their application to automatic gearboxes without technical retrofitting, and face challenges in achieving a long stroke within the limited assembly space.

Innovation Solution

A shift drive mechanism with a rack capable of recoverable deformation, integrated with a gear housing and take-up release section, allowing the rack to extend its stroke without increasing volume, and adaptable to different track lengths through curvature adjustments, enabling application to automatic gearboxes without retrofitting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the track length is extended to provide long stroke for automatic gearbox shifting, then the shifting function is improved, but the volume of the electronic shift driver increases

Engineering Contradiction:
Improvestroke lengthVSAvoidvolume of electronic shift driver
Core Design Contradiction:
Length of moving objectVSVolume of stationary object

Solution Approach 1:

The track slot is designed with a curved take-up release section instead of a straight line. The rack follows this curved path, allowing it to extend its stroke length by utilizing the curvature of the track slot within the gear housing, thereby achieving long stroke without proportionally increasing the overall volume of the electronic shift driver.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The track slot transitions from a one-dimensional straight rail section to a two-dimensional curved path by adding the take-up release section. This dimensional change allows the rack to achieve greater displacement in a compact space by utilizing the curved geometry rather than a simple linear extension.

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

2Ease of manufacture

If the electronic shift driver is designed with fixed track length, then the manufacturing is simplified, but the adaptability to different gearboxes is reduced

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidadaptability to different gearboxes
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The track slot is designed with a curved take-up release section that can be adjusted in curvature radius. This dynamic design parameter allows the same basic structure to be adapted to different gearboxes by modifying the curvature radius, thereby maintaining manufacturing simplicity while achieving versatility across different applications.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The curvature radius of the take-up release section can be changed as a design parameter to accommodate different gearbox requirements. By adjusting this single parameter, the electronic shift driver can be adapted to various applications without requiring complete redesign, thus maintaining ease of manufacture while improving adaptability.

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

Enables the shift drive to achieve the same shifting function as an electronic shifter for automatic gearboxes, providing a long stroke within the same space and accommodating various track lengths, enhancing versatility and modularization.

Implementation Method 1

a rack (3) linked with the actuating mechanism (6), at least one end of the rack (3) being capable of a recoverable deformation

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3779243B1Shift driving device
Publication Date: 2023.08.23 FICOSA INTERNATIONAL (TAICANG) CO LTD

AI summary

A shift drive, comprising: an actuating mechanism 6 capable of being driven by a driving mechanism 1; a rack 3 linked with the actuating mechanism 6, at least one end of the rack being capable of a recoverable deformation, the rack 3 including a connection portion, the connection portion being connected to the actuating mechanism 6 through a connecting member 301; a gear housing 5 provided with an induction gear 4 that meshes with the rack 3, the gear housing having a track slot 501 that receives the rack therein, the track slot 501 having a take-up release section 501a and a straight rail section 501b, wherein an end portion of the rack 3 that is capable of a recoverable deformation can slide in or out of the take-up release section 501a, and the length of projection of the take-up release section 501a on an extension line in the direction of the length of the straight rail section 501b is less than the length of the track thereof. The shift drive according to the embodiment of the present invention can be applicable to an automatic gearbox of an existing known construction, such that the shift drive can achieve the same shifting function as an electronic shifter without technical retrofitting.