Manual Transmission Synchronizer Convex Tooth Geometry
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Solution Overview
Problem
Existing manual transmission synchronizing devices face challenges in achieving a small axial length and low torsional backlash while ensuring reliable meshing of sliding sleeve teeth with clutch body teeth, particularly in modern automated transmissions like double clutch transmissions.
Innovation Solution
The synchronizing device features a sliding sleeve with internal teeth and a clutch body with external teeth, where the clutch body teeth and sliding sleeve teeth have convex end faces that reduce material stress and wear, allowing for a compact design with minimal axial length and low torsional backlash, and includes a synchronizing unit that can be force-controlled for precise engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the axial length of the synchronizing device is reduced, then the compactness is improved, but the reliable meshing of sliding sleeve teeth with clutch body teeth becomes difficult to ensure
Solution Approach 1:
The invention applies convex end faces (curved surfaces) to the sliding sleeve teeth and clutch body teeth instead of flat or pointed ends. This curvature allows the teeth to gradually engage and guide each other into proper meshing position, ensuring reliable engagement even with reduced axial length. The convex shape creates a self-centering effect that maintains meshing reliability in a compact design.
2Manufacturing precision
If the torsional backlash is reduced, then the precision of engagement is improved, but the material stress and wear in the tooth transition area increase
Solution Approach 1:
The convex end faces with continuous curvature distribute the contact stress over a larger area during engagement. The curved surface allows for gradual load transfer and reduces stress concentration at sharp edges or points, thereby lowering material stress and wear while maintaining low torsional backlash through precise geometric control.
Solution Approach 2:
The invention optimizes the geometric parameters of the convex end faces, specifically controlling the axial distance between the apex portion and base points to be at most 18% (preferably at most 10%) of the tooth width. This parameter optimization achieves the right balance between reducing torsional backlash and minimizing material stress by controlling the engagement profile and contact distribution.
Data Source
Figure 1~2
Figure 3~7b
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AI summary
The invention relates to a synchronizing device (10) and a synchronizing method for a manual transmission, comprising a sliding sleeve (12) having internal teeth with sliding sleeve teeth (18), a clutch body (14) of a gear wheel having external teeth with a plurality of clutch body teeth (20) into which the internal teeth of the sliding sleeve (12) can engage, and a synchronizing unit, wherein the clutch body teeth (20) at their axial tooth end adjacent to the sliding sleeve (12) and/or at least some of the sliding sleeve teeth (18) at their axial tooth end adjacent to the clutch body (14) each have at least one convex end face, which extends circumferentially from a root point (28) adjacent to a tooth flank (30) of the respective tooth (18, 20) via an axially projecting apex section (32) to a root point (34) adjacent to a opposite tooth flank (36) of the tooth (18,20) or extends to a valley point between two adjacent convex end faces. An axial distance (a) between the apex section (32) and each of the foot points (28, 34) is at most 18% of a tooth width (b).