Transmission Synchronizer Key Assembly Motion Conversion
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Solution Overview
Problem
The existing synchromesh type shift mechanisms face challenges in achieving sufficient durability of parts and reducing the actuator capacity for sleeve movement, as they require significant force for synchronization.
Innovation Solution
A synchronizer design featuring a bottom key and top key with radial and axial sliding capabilities, a key spring for pressure, and a motion converting portion that converts circumferential motion into axial motion to enhance synchronization with reduced force, including radial grooves, projections, and inclined surfaces for efficient engagement with the synchro-ring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional synchromesh shift mechanism is used, then power transmission is achieved, but the actuator capacity required for sleeve movement is large and part durability is insufficient
Solution Approach 1:
The key assembly is divided into two separate keys: a bottom key that rotates with the hub and a top key that moves axially with the sleeve. This segmentation allows each key to perform its specific function optimally - the bottom key provides rotational synchronization while the top key provides axial engagement, improving overall reliability and reducing the force required for synchronization.
Solution Approach 2:
The top key acts as an intermediary element between the sleeve and the synchro-ring. Instead of the sleeve directly pressing the synchro-ring, the top key transmits the axial force, distributing the load and reducing stress concentrations, thereby improving part durability and reducing the required actuator capacity.
2Reliability
If the sleeve is moved axially with large force, then synchronization is achieved, but the actuator capacity must be large
Solution Approach 1:
The bottom key is designed to rotate dynamically with the hub during the synchronization process, while the top key moves axially. This dynamic motion conversion allows the system to achieve synchronization with reduced axial force on the sleeve, thereby reducing the actuator capacity required while maintaining effective synchronization.
Solution Approach 2:
The invention introduces a rotational dimension through the bottom key's circumferential movement, converting part of the synchronization task from purely axial motion to a combination of rotational and axial motion. This dimensional change reduces the force requirement in the axial direction, allowing for a smaller actuator capacity.
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 improves the durability of the synchromesh type shift mechanism and reduces the actuator capacity required for sleeve movement by enabling effective synchronization with less force, ensuring efficient power transmission and increased mechanical reliability.
Implementation Method 1
a key spring disposed between the bottom key and the hub to press the bottom key and the top key toward an internal side of the sleeve
Implementation Method 2
the speeds of the hub, the sleeve, and a clutch gear are synchronized by friction force generated between the synchronizer ring and the clutch cone of the clutch gear
Data Source
AI summary
A synchronizer of a transmission may include bottom key disposed on a hub to be slidable in a radial direction of the hub; a top key disposed radially outside the bottom key to be slidable in an axial direction of the hub; a sleeve disposed outside the hub and sliding in the axial direction to slide the top key in the axial direction to press a synchro-ring; a key spring disposed between the bottom key and the hub to press the bottom key and the top key toward an internal side of the sleeve; and a motion converting portion converting relative motion generated in a circumferential direction of the hub between the top key and the bottom key into axial relative motion of the top key to the bottom key toward the synchro-ring.