Synchromesh Shift Sleeve Overlap for Power Continuity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional synchromesh mechanisms experience a neutral period during gear shifting, leading to power cutoff and a driver's feeling of free running in vehicles with automatic transmission, as they disconnect from one dog clutch gear before engaging the other.
Innovation Solution
The synchromesh mechanism is designed with a shift sleeve of sufficient length to contact both synchronizer rings simultaneously, reducing the time between disengagement from one gear and engagement with the next, and incorporating slanted surfaces and circumferential grooves to facilitate smoother transitions and reduced operating force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shift sleeve is designed with conventional length, then the structure is simpler and manufacturing is easier, but there is a neutral period during gear shifting causing power cutoff and driver discomfort
Solution Approach 1:
The shift sleeve is designed with extended length to contact both synchronizer rings simultaneously during the shifting process. This preliminary configuration ensures that as the shift sleeve moves from one gear position to another, it maintains continuous engagement with at least one synchronizer ring, eliminating the neutral period where power transmission is interrupted. The extended structure enables overlapping engagement phases between different gears.
2Reliability
If the shift sleeve contacts both synchronizer rings simultaneously, then power cutoff is suppressed, but the operating force required increases
Solution Approach 1:
Slanted surfaces are incorporated at the ends of the shift sleeve where it contacts the synchronizer rings. These inclined surfaces allow the shift sleeve to gradually engage or disengage from the synchronizer rings during the shifting process. The slanted geometry distributes the contact force over a longer distance and time period, reducing the peak operating force required while maintaining continuous power transmission through simultaneous contact with both synchronizer rings.
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 suppresses power cutoff and the sensation of free running by minimizing the neutral period during gear shifts, ensuring smoother transitions and reduced driver discomfort.
Implementation Method 1
This contacts the synchronizer ring to the cone portion to generate frictional torque
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A synchromesh mechanism includes a shaft, a shift sleeve, a first gear and a second gear arranged at the both sides of a hub, and a first synchronizer ring and a second synchronizer ring arranged at the both side of the hub. The shift sleeve has a length so that it can start contacting with the first synchronizer ring and the second synchronizer ring at the same time.