Transmission Synchronizer Auxiliary Teeth Backlash Control
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Solution Overview
Problem
Existing transmission synchronizers cause torque interruption and rattle noise during gear shifting, leading to shocks and noise issues when the sleeve is removed, and increasing backlash exacerbates these problems.
Innovation Solution
A transmission synchronizer design featuring a sleeve with radially protruding main and auxiliary teeth, where the auxiliary teeth have a lower height than the main teeth, allowing for controlled engagement and disengagement with clutch gears to minimize collisions and noise, while maintaining sufficient backlash to prevent torque interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backlash of the synchronizer is increased to prevent shock during gear shifting, then torque interruption is reduced, but rattle noise occurs during vehicle traveling
Solution Approach 1:
The sleeve is divided into multiple teeth (first teeth and second teeth) that engage with different portions of the gear teeth at different stages of engagement, allowing controlled backlash management during both engagement and disengagement phases
Solution Approach 2:
The second teeth engage with the lower portions of the gear teeth before the first teeth fully engage with the upper portions, preliminarily establishing a connection that controls backlash before full engagement is achieved
2Adaptability or versatility
If the synchronizer is removed to enable gear shifting, then gear changes are possible, but shock occurs due to sleeve and gear collision
Solution Approach 1:
The sleeve teeth are segmented into first teeth and second teeth with different engagement characteristics, allowing the disengagement process to be divided into stages that control collision forces
Solution Approach 2:
Different portions of the gear teeth (upper portions and lower portions) are designed with different engagement properties, where the second teeth engage with lower portions that have different backlash characteristics to reduce collision shock
3Device complexity
If the synchronizer structure is simplified to reduce complexity, then manufacturing is easier, but noise and vibration performance deteriorates
Solution Approach 1:
The sleeve with its multiple teeth serves multiple functions: it provides both engagement and disengagement control, manages backlash in both directions, and reduces both collision shock and rattle noise, eliminating the need for separate components
Solution Approach 2:
The second teeth preliminarily engage with the lower portions of gear teeth to establish controlled backlash before the first teeth fully engage, preventing both excessive collision and rattle noise
Data Source
AI summary
A transmission synchronizer apparatus may include a sleeve coupled to an external peripheral surface of a hub gear while moving axially, and clutch gears disposed at both sides of the hub gear, each selectively synchronizing and engaging with the sleeve according to the axial movement of the sleeve, wherein the transmission synchronizer includes a plurality of main sleeve teeth protruding radially from an internal peripheral surface of the sleeve while being distanced from one another, and an auxiliary sleeve tooth protruding radially from the internal peripheral surface of the sleeve while protruding from one side of each of the main sleeve teeth to have a height lower than the main sleeve tooth.