Claw Clutch Speed Synchronization via Torque Control
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Solution Overview
Problem
Existing drive train systems with claw clutches experience issues of tooth-on-tooth positions, which impair shifting comfort and increase wear on shifting elements, and current methods do not effectively reduce their occurrence or resolve them safely and comfortably.
Innovation Solution
Applying a torque to the claw clutch via internal or external assemblies to achieve a desired differential speed before closing, using reduced torque to manage frictional forces, and employing various components like transmission brakes, oil pumps, and actuating cylinders to safely and gently resolve tooth-on-tooth positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If claw clutches are used for shifting in the transmission, then the transmission can be operated automatically with simplified control, but tooth-on-tooth positions occur which impair shifting comfort and increase wear on shifting elements
Solution Approach 1:
The patent applies preliminary action by determining the rotational speeds of both clutch hubs before engaging the claw clutch, calculating the optimal engagement timing in advance, and pre-positioning the clutch actuator. This ensures that the clutch engages at the optimal moment when tooth-on-tooth positioning is minimized, thereby maintaining automatic operation while improving shifting comfort and reducing wear.
Solution Approach 2:
The patent implements feedback by continuously monitoring the rotational speeds of the clutch hubs during the shifting process, using this information to dynamically adjust the engagement timing of the claw clutch. This closed-loop control ensures that the clutch engages at the optimal moment based on real-time conditions, reducing tooth-on-tooth positions and improving shifting comfort while maintaining automatic operation.
2Productivity
If claw clutches are engaged without speed synchronization, then shifting can be performed quickly, but tooth-on-tooth positions occur which increase wear on shifting elements
Solution Approach 1:
The patent applies preliminary action by calculating the optimal engagement timing before the clutch engagement begins, based on the current rotational speeds of both clutch hubs. The system determines the precise moment when engagement will occur and adjusts the timing accordingly, enabling fast shifting while minimizing tooth-on-tooth positions and reducing wear on shifting elements.
Solution Approach 2:
The patent changes the timing parameter of clutch engagement based on the rotational speeds of the clutch hubs. By dynamically adjusting the engagement timing parameter rather than using fixed timing, the system achieves fast shifting speeds while avoiding tooth-on-tooth positions that would increase wear, thus resolving the contradiction between productivity and reliability.
3Ease of operation
If torque is applied to resolve tooth-on-tooth positions after they occur, then shifting comfort can be improved, but the resolution process takes additional time
Solution Approach 1:
The patent applies preliminary anti-action by preventing tooth-on-tooth positions from occurring in the first place through optimal engagement timing determination. By calculating and applying the correct engagement timing before the clutch engagement begins, the system avoids creating tooth-on-tooth positions that would later require torque-based resolution, thereby improving shifting comfort without adding time delays.
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
Reduces the probability of tooth-on-tooth positions occurring and allows for their safe, quick, and comfortable resolution, enhancing shifting comfort and reducing wear on shifting elements.
Implementation Method 1
a frictional torque which can at least correspond to a frictional torque of a tooth-on-tooth position on the dog clutch when the dog clutch is engaged
Implementation Method 2
actuating a clutch actuator with a closing force
Implementation Method 3
actuating a clutch actuator with a closing force, wherein the closing force is reduced when a tooth-on-tooth position is present
Data Source
Figure 1
AI summary
This new procedure minimizes the probability of engaging a dog clutch in a tooth-on-tooth position. A moment is applied to the dog clutch via an assembly. The assembly is internal or external to the gears. The applied moment result results in a difference speed at the dog clutch, which approximates to a predetermined desired value. The dog clutch is not engaged until the difference speed has reached the given desired value.