Clutch Jaw Tooth Profile Design for Reducing Separating Load
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Solution Overview
Problem
Clutches in high-speed applications, such as aircraft generators, face challenges in separating the clutch members due to large negative rake angles, leading to increased torque requirements and axial loads, which necessitate robust gearbox designs and potential energy storage issues.
Innovation Solution
The clutch teeth are designed with a negative rake angle between 1° and 2° and a chamfer angle between 65° and 75°, reducing the angular twist and axial load required for separation, and minimizing the torque spike imparted to the gearbox.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large negative rake angle (e.g., 5°) is used on clutch teeth, then the clutch teeth can effectively transmit torque during rotation, but the separating force required to disengage the clutch increases significantly
Solution Approach 1:
The patent applies parameter changes by modifying the negative rake angle from a conventional large value (e.g., 5°) to a reduced value between 1° and 2°. This parameter optimization maintains sufficient torque transmission capability while significantly reducing the separating force required for clutch disengagement, thereby resolving the technical contradiction between strength and force requirements.
2Strength
If a large negative rake angle is used on clutch teeth, then torque can be transmitted during engagement, but the torque spike required to overcome the negative rake angle during decoupling increases, necessitating robust gearbox design
Solution Approach 1:
By changing the negative rake angle parameter to a reduced value (1°-2°), the patent minimizes the torque spike that occurs during clutch decoupling. This reduces the additional torque loading on the gearbox, allowing for less robust and more compact gearbox design while maintaining adequate torque transmission capability during normal operation.
3Ease of manufacture
If a chamfered end of the tooth profile at a small angle (e.g., 45°) is used, then the tooth structure can be formed, but axial load on the input shaft and support bearing increases during separation
Solution Approach 1:
The patent applies parameter changes by optimizing the chamfer angle at the tooth profile end from a conventional small angle (e.g., 45°) to a larger value between 65° and 75°. This angle optimization maintains manufacturability of the tooth profile while significantly reducing the axial load imposed on the input shaft and support bearing during clutch separation.
Data Source
AI summary
A shaft for a clutch member comprises an engagement portion having a plurality of teeth spaced about a shaft centerline. The teeth have a tooth profile with a negative rake angle. The negative rake angle is between 1° and 2°. The teeth have a chamfer angle between the face of the negative rake and the face of the clutch end surface. The chamfer angle is between 65° and 75°. A rotor assembly for a generator, a generator and a method are also disclosed and claimed.