Synchronous Engagement Clutch With Centrifugal Ball Weights
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Solution Overview
Problem
Existing synchronous engagement clutches for gas turbine engines face challenges in efficiently engaging and disengaging torque transmission due to the limitations of shallow flyweight pockets and centrifugal forces, which affect the clutch's ability to maintain engagement during startup and disengage properly after ignition.
Innovation Solution
A clutch assembly with a design featuring a ball guide starter and output component with annular weight tracks and contoured engagement/disengagement weight pockets, utilizing centrifugal forces and a spring mechanism to ensure ratcheting engagement and disengagement, allowing the output shaft to turn faster than the drive member and maintaining engagement when rotational speeds are equal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shallow flyweight pockets are used in conventional clutches, then the clutch structure is simpler, but the clutch cannot maintain reliable engagement during startup and disengage properly after ignition
Solution Approach 1:
The patent employs spherical flyweights that interact with curved engagement surfaces. The flyweights are driven outward by centrifugal force along curved paths, and the spherical geometry allows them to engage and disengage smoothly while maintaining reliable contact. The curvature of the engagement surfaces complements the spherical shape of the flyweights, ensuring consistent force transmission and reliable engagement throughout the operational cycle.
Solution Approach 2:
The clutch mechanism dynamically adjusts the position of flyweights based on rotational speed. At low speeds, spring force keeps flyweights retracted for disengagement. As speed increases, centrifugal force overcomes spring force and drives flyweights outward to engage the clutch. This dynamic response ensures reliable engagement only when needed, while allowing proper disengagement at lower speeds.
2Ease of operation
If centrifugal forces are used to drive flyweights outward, then the clutch can engage automatically with speed, but the clutch cannot disengage properly when the power source is cut off
Solution Approach 1:
The patent uses spring force as a counteracting force to balance centrifugal force. The spring is pre-loaded to push flyweights inward toward the disengaged position. When the power source is cut off and rotational speed decreases, centrifugal force diminishes and the spring force dominates, reliably pushing flyweights inward to disengage the clutch. This counterbalancing mechanism ensures both automatic engagement at high speed and reliable disengagement when speed drops.
3Adaptability or versatility
If the output shaft needs to turn faster than the drive member, then the clutch can accommodate speed differences, but the engagement mechanism becomes more complex
Solution Approach 1:
The spherical flyweights with curved engagement surfaces naturally accommodate speed differences between the drive member and output shaft. The curved geometry allows the flyweights to maintain contact while permitting relative motion and speed variation. This enables the output shaft to accelerate faster or rotate at different speeds without compromising engagement integrity, providing adaptability through geometric design rather than complex mechanical constraints.
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
The clutch assembly effectively transfers torque during engine startup and disengages efficiently after ignition, ensuring reliable operation by utilizing centrifugal forces and a spring mechanism to manage the engagement and disengagement of the clutch.
Implementation Method 1
the engagement weights each having a radius 31, and a diameter equal to twice the radius 31. The groove 22 and engagement weight pockets 28 are respectively contoured to generally provide decreasing axial distance between each other with increasing radial distance from the axis X. Thus, radially outward travel of the engagement weights 30 biases the movable component 18 and drive teeth 20 toward the output component 12 and output teeth 16.
Implementation Method 2
In further embodiments, the drive teeth 20 and output teeth 16 are opposing sawtooth face gears biased into engagement by a spring 35
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A clutch assembly includes an output shaft (12) extending along an axis and output teeth. A movable component (18) is disposed adj acent to the output component. The movable component includes drive teeth and an annular engagement weight track (21) including a groove circumscribing the axis. The movable component is movable between an engaged position, wherein the drive teeth are drivingly engaged with the output teeth, and a disengaged position, wherein the drive teeth are not engaged with the output teeth. An input component is disposed adjacent to the movable component. The input component includes engagement weight pockets. Spherical engagement weights (30) are disposed in each engagement weight pocket. The groove has a generally uniform radial cross section across its circumference.