Two-Way Clutch Speed Synchronization Control
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Solution Overview
Problem
The existing power transmission systems for vehicles experience shock during the transition period when switching a two-way clutch from a one-way mode to a lock mode due to significant rotational speed differences between input and output members, leading to increased manufacturing costs and reduced durability.
Innovation Solution
A control apparatus is introduced that includes an electronic control unit to synchronize the rotational speeds of the input and output members before switching the two-way clutch to the lock mode, utilizing torque increase control and temporary reduction of clutch torque capacity to minimize shock and enhance controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-way clutch is used instead of a dog clutch with synchro mechanism, then manufacturing cost is reduced, but shock is generated during switching to lock mode due to rotational speed difference
Solution Approach 1:
The control apparatus performs preliminary speed synchronization by controlling the rotational speed of the input-side rotary member to match the output rotational speed before switching the two-way clutch to lock mode. This preliminary action eliminates the rotational speed difference that would otherwise cause shock during the transition.
Solution Approach 2:
The control apparatus dynamically adjusts the rotational speed parameter of the input-side rotary member to achieve synchronization with the output rotational speed. By changing this parameter before clutch switching, the system prevents shock while maintaining the simplified two-way clutch structure.
2Speed
If the two-way clutch is switched to lock mode immediately, then response time is improved, but shock and durability issues occur due to large rotational speed difference
Solution Approach 1:
The control apparatus executes preliminary speed synchronization control before the clutch switching operation. This ensures that when the two-way clutch transitions to lock mode, both input and output members are already synchronized in speed, eliminating shock and protecting the clutch durability.
Solution Approach 2:
The control apparatus continuously monitors the rotational speeds of both input-side and output-side rotary members, using this feedback information to determine when speed synchronization has been achieved and to timing the clutch switching operation appropriately.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A control apparatus of a power transmission system (16; 148; 178) for a vehicle includes an electronic control unit (100; 150; 180). When an input rotational speed of an input-side rotary member (68) is lower than an output rotational speed of an output-side rotary member (70) in a two-way clutch (TWC), and a shift request to form a shift stage in which the two-way clutch is switched to a lock mode is generated, the electronic control unit (100; 150; 180) switches the two-way clutch (TWC) to the lock mode, after the input rotational speed of the input-side rotary member (68) is made substantially equal to the output rotational speed of the output-side rotary member (70).