Shift Fork Ring Structure for Lower Sleeve Contact Wear

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Solution Overview

Problem

The existing shift control devices wear out the shift fork due to pressing it against the rotating sleeve over its entire circumference, leading to premature wear.

Innovation Solution

The shift control device incorporates a sleeve with a first convex section and a shift fork with a second convex section and a ring, where the ring is secured by a joining member, distributing the pressure over a larger area to reduce surface pressure on the shift fork, and includes sliding members to further reduce wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the shift fork presses against the entire circumference of the rotating sleeve to select a gear, then the gear selection function is achieved, but the shift fork is likely to wear off

Engineering Contradiction:
Improvegear selection functionVSAvoidservice life of shift fork
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The invention divides the contact interface into discrete convex sections rather than continuous circumferential contact. The sleeve has a first convex section and the shift fork has a second convex section, creating localized contact points that segment the wear distribution and reduce overall wear on the shift fork.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies local quality by creating specific convex sections with defined contact areas rather than uniform circumferential contact. The first convex section on the sleeve and second convex section on the shift fork provide localized high-contact zones that concentrate the gear selection force while minimizing wear on the shift fork.

Inventive Principle:
Principle #3Local quality

2Reliability

If the shift fork presses against the rotating sleeve over its entire circumference, then gear selection is achieved, but surface pressure on the shift fork increases

Engineering Contradiction:
Improvegear selection functionVSAvoidsurface pressure on shift fork
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The contact surface is segmented into discrete convex sections, distributing the pressing force over multiple localized areas rather than concentrating it along the entire circumference, thereby reducing surface pressure on the shift fork.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional circumferential contact surface to a three-dimensional configuration with convex sections that extend in the axial direction. This dimensional change allows the pressing force to be distributed over a larger effective area, reducing surface pressure.

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

Data Source

PatentEP3978785B1Shift control device
Publication Date: 2023.11.22 UNIVANCE CORP
  • EP3978785B1 patent drawingFigure 1
  • EP3978785B1 patent drawingFigure 2
  • EP3978785B1 patent drawingFigure 3

AI summary

Provided is a shift control device that is capable of suppressing the wear of a shift fork. A sleeve (11) in the shift control device (10) includes a sleeve main body (12) and a first convex section (14). The sleeve main body (12) is annular in shape. The first convex section (14) is annular in shape and protruded radially outward from the outer circumferential surface (13) of the sleeve main body (12). The shift fork (20) includes a fork main body (21), a second convex section (24), a ring (40), and a joining member (50). The fork main body (21) is annular in shape and disposed radially outside the sleeve main body (12). The second convex section (24) is annular in shape, axially disposed side by side with the first convex section (14), and protruded radially inward from the inner circumferential surface (23) of the fork main body (21). The ring (40) is annular in shape and disposed to axially sandwich the first convex section (14) between the ring (40) and the second convex section (24). A first groove (42) is formed in the outer circumferential surface (41) of the ring (40) and extended in a circumferential direction. The joining member (50) is disposed in a space that is formed by the first groove (42) and a second groove (27) formed in the fork main body (21).