Transmission Synchronizer Sleeve Movement Regulation
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Solution Overview
Problem
In synchronizers for transmissions, especially when gears have small diameters, there is a risk of uneven wear or damage due to differential rotation between the sleeve and other gears, which existing solutions attempt to mitigate through additional components like stoppers, increasing complexity and cost.
Innovation Solution
The synchronizer design incorporates a shift rail with integrated first and second shift forks, allowing the first and second sleeves to move in opposite directions, with the second sleeve's movement regulated by a stopper, ensuring that the sleeves do not come into contact with adjacent gears, thereby preventing wear and damage without the need for additional stopper components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stopper is added to regulate sleeve movement, then the risk of uneven wear or damage is reduced, but the device complexity and cost increase
Solution Approach 1:
The stopper function is merged with the existing hub structure by forming a retaining portion integrally with the hub. This eliminates the need for a separate stopper component while maintaining the protective function against sleeve-gear contact damage.
Solution Approach 2:
The hub structure is given multiple functions: it serves both as the mounting structure for spline teeth and as the stopper (retaining portion) that prevents excessive sleeve movement. This multi-functionality reduces the overall number of components needed in the synchronizer assembly.
2Ease of operation
If the sleeve is allowed to move freely to synchronize the gear, then the synchronization function is achieved, but the sleeve may contact adjacent gears causing wear
Solution Approach 1:
The retaining portion is pre-positioned on the hub to prevent the sleeve from moving too far and contacting adjacent gears. This preliminary protective structure stops the harmful contact before it can occur, allowing free movement within safe limits.
Solution Approach 2:
The retaining portion acts as an intermediary element between the sleeve and the adjacent gear, preventing direct contact between the sleeve and the gear that would cause wear. It mediates the movement to ensure safe operation.
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
This design effectively prevents sleeve-gear contact issues, reducing the number of components and assembly steps, lowering costs, and minimizing transmission size, while ensuring reliable synchronization without differential rotation-induced damage.
Implementation Method 1
the conical surfaces of the blocking ring and the gear come into contact with each other so that a frictional force is generated which synchronizes the gear with the rotating shaft
Data Source
AI summary
A synchronizer for a transmission includes a shift rail, a first sleeve, a second sleeve, and a stopper. The shift rail includes a first shift fork and a second shift fork that are provided integrally with each other. The first sleeve is movable in a first direction along an axial direction from a predetermined first standby position to synchronize a first gear with a rotating shaft. The second sleeve is movable in a second direction along the axial direction from a predetermined second standby position to synchronize a second gear with the rotating shaft. A distance between the second sleeve at the predetermined second standby position and the stopper in the axial direction is smaller than a distance between the first sleeve at the predetermined first standby position and the third gear in the axial direction.