Synchronizer Re-energization for Cold Shift Comfort
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Solution Overview
Problem
The existing synchronizer mechanisms in manual transmissions experience wear and undesirable shifting due to differences in angular velocities between the synchronizer sleeve and adjacent gears, particularly in colder conditions before the transmission reaches operating temperature, leading to friction loss and increased wear.
Innovation Solution
The synchronizer mechanism energizes the intermediate clutch ring twice as the synchronizer sleeve moves from the neutral position to an adjacent gear, minimizing the difference in angular velocities by ensuring synchronized rotation through a dual engagement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the synchronizer sleeve moves directly from neutral to engage the adjacent gear, then the shifting operation is completed in one step, but the angular velocity difference between the sleeve and gear causes wear and notchy shifting
Solution Approach 1:
The engagement process is segmented into two distinct phases: first engaging the intermediate clutch ring to synchronize angular velocities, then engaging the final gear. This segmentation allows the system to complete the shifting operation while minimizing wear by ensuring velocity matching at each stage.
Solution Approach 2:
The intermediate clutch ring performs a preliminary synchronization action before the final gear engagement. By first matching the angular velocities through the clutch ring's friction surface, the system prepares the components for smooth final engagement, preventing wear and notchy shifting.
2Device complexity
If the synchronizer mechanism uses a single engagement phase, then the structure is simpler, but friction loss occurs when angular velocities differ
Solution Approach 1:
The synchronizer mechanism is divided into two functional components: the intermediate clutch ring for velocity synchronization and the final gear engagement structure. This segmentation enables energy-efficient operation by eliminating friction loss through proper velocity matching before power transmission.
Solution Approach 2:
The intermediate clutch ring acts as an intermediary element between the synchronizer sleeve and the final gear. It mediates the velocity difference by providing a friction surface that synchronizes angular velocities, thereby eliminating harmful friction loss during the transition.
3Speed
If the synchronizer sleeve engages the gear without velocity synchronization, then the mechanism is faster, but the shifting becomes loud and notchy
Solution Approach 1:
The system performs preliminary velocity synchronization through the intermediate clutch ring before the final gear engagement. This preliminary action ensures that when the sleeve engages the gear, the angular velocities are matched, resulting in smooth and quiet shifting without notchy sounds.
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 approach reduces wear on transmission parts and improves shifting smoothness by maintaining synchronized rotation, reducing the likelihood of notchy and loud shifting across varying temperatures.
Implementation Method 1
The contact between the interior cone shaped surface of the intermediate clutch ring and the exterior cone shaped surface of the adjacent gear creates friction and causes the adjacent gear and intermediate clutch ring to rotate at the same angular velocity.
Data Source
AI summary
A synchronizer mechanism for synchronizing the rotation of gears between a power input shaft and a power output shaft in a manual transmission includes a hub and a synchronizer sleeve disposed about the hub and moveable relative thereto into and out of engagement with adjacent gears to synchronize the rotation of the adjacent gears with the rotation of the power input shaft. An indexing mechanism is employed for indexing the synchronizer sleeve into and out of engagement with adjacent gears. The indexing mechanism includes a retaining mechanism and a detent portion having a main synchronization detent and at least one second synchronization detent disposed laterally adjacent the main synchronization detent. The main synchronization detent causes an intermediate clutch ring to contact a cylindrical cone portion on a gear and begin the change in angular velocity of the gear and to begin the synchronization sequence of the mechanism at a first time. The second synchronization detent causes the intermediate clutch ring to contact a cylindrical cone portion on a gear and change the angular velocity of the gear and synchronizer mechanism at a second time reducing the minor speed difference between the gear and synchronizer sleeve caused by loss of synchronization between the time of sleeve and ring indexing and initial engagement contact of the sleeve to the clutch teeth of the gear.