Dog Clutch Partial Engagement via Sensor Sleeve
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Solution Overview
Problem
Automatic transmissions with dog clutches require a longer time for synchronization and engagement, leading to slower gear shifts, which is undesirable for improved shifting performance.
Innovation Solution
A system that includes an actuation piston, a dog clutch, a sensor sleeve, and a control system, where the sensor sleeve determines the partial engagement position of the dog clutch members by sensing hydraulic fluid pressure and movement, allowing for faster shift times without the need for additional electronic sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dog clutch is used for gear shifting, then the transmission can achieve reliable gear engagement, but the synchronization and engagement time increases, leading to slower shifting performance
Solution Approach 1:
The patent applies partial action by introducing a sensor sleeve that detects a predetermined position during the engagement process. The system determines when the dog clutch members have reached a specific engagement state (where the male member is received inside the female member for a predetermined amount of axial overlap) and commands the shift to complete at this partial engagement point rather than waiting for full engagement. This reduces the total engagement time while maintaining sufficient gear connection reliability.
2Reliability
If the dog clutch is allowed to engage fully before commanding the shift, then complete gear engagement is achieved, but the shifting duration is extended
Solution Approach 1:
The patent implements feedback through a sensor sleeve that continuously monitors the engagement position of the dog clutch members. The sensor sleeve includes a reduced diameter sensor portion that contacts the input shaft chamber wall at a predetermined engagement position, generating a signal that feeds back to the control system. This feedback mechanism allows the control system to command the shift completion at the optimal moment when sufficient engagement has been achieved, balancing reliability with shifting speed.
3Measurement precision
If additional electronic sensors are added to detect clutch engagement position, then precise shift timing can be achieved, but the device complexity and cost increase
Solution Approach 1:
The patent applies self-service by designing the sensor sleeve to utilize the existing hydraulic circuit and structural components of the transmission. The sensor sleeve uses the natural movement of the actuation piston and the existing input shaft chamber wall as a reference surface. The reduced diameter sensor portion of the sleeve contacts the chamber wall at a predetermined position, allowing the system to self-detect the engagement state without requiring external electronic sensors or additional complex measurement systems.
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 solution reduces the time required for gear shifts by determining the partial engagement position of the dog clutch, enabling faster and improved shifting performance in automatic transmissions.
Implementation Method 1
determine the partial engagement position of the dog clutch members by sensing hydraulic fluid pressure and movement
Data Source
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AI summary
A transmission having an input shaft, piston, dog clutch, sensor sleeve and control system is provided. The dog clutch (A) includes male and female members (50, 58), where one of the members is coupled to the piston (66) for common movement therewith. The sleeve (88) includes a through channel (112) and a reduced diameter sensor portion (128) terminating at a shoulder (124). The control system is configured to: command a supply of hydraulic fluid against an engagement side of the piston, determine when a terminal end of the sensor portion contacts a control, and determine that the dog clutch members are in a predetermined partially engaged state less than a fully engaged state of the dog clutch members. A length of the reduced diameter sensor portion (128) directly corresponds to the predetermined partially engaged state of the dog clutch that is less than a fully engaged state of the male and female members of the dog clutch.