Overrunning Clutch Pawl Assembly Stability
Solution Overview
Problem
Existing overrunning clutches face challenges in maintaining pawl assembly when the toothed race is removed, requiring costly rearward biasing methods and complex design considerations for pivot points and pocket geometry, limiting design flexibility and increasing packaging size.
Innovation Solution
A spring biasing mechanism is applied to the top rear portion of the pawl, using flat or ribbon springs to trap the pawl when the races are disassembled, allowing the pawls to remain assembled to the inner race and enabling self-centering in the pocket, reducing size and packaging requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If accordion spring biasing is used at the front of the pawl, then manufacturing cost is reduced, but the pawl cannot remain assembled when the toothed race is removed
Solution Approach 1:
The invention extracts the biasing function from the toothed race assembly by using a separate spring mechanism that biases the pawl rearward independently. This allows the pawl to remain assembled to the inner race even when the outer race (toothed race) is removed, resolving the contradiction between low-cost accordion spring biasing and assembly stability.
Solution Approach 2:
The invention introduces a spring as an intermediary element that mediates between the pawl and the races. This spring applies rearward biasing force to keep the pawl assembled to the inner race, enabling the pawl to remain in place during disassembly of the outer race while maintaining simple manufacturing.
2Stability of the object's composition
If rearward biasing using garter spring is used, then pawl assembly stability is improved, but manufacturing cost increases and design complexity increases
Solution Approach 1:
The invention applies local quality by positioning the spring biasing mechanism specifically at the rear of the pawl rather than using complex garter spring arrangements. This localized approach maintains assembly stability while simplifying the overall design and reducing manufacturing complexity compared to garter spring systems.
3Stability of the object's composition
If complex pivot point and pocket geometry design is used, then pawl assembly stability is improved, but device complexity and packaging size increase
Solution Approach 1:
The invention extracts the assembly stability function from complex pivot point and pocket geometry designs by using spring biasing. This allows for simpler, more compact pivot points and pockets, reducing the overall envelope size of the clutch while maintaining the ability of pawls to remain assembled during disassembly.
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 configuration enhances design flexibility, reduces the envelope size of the clutch, and simplifies assembly by using the clamping action of the spring, ensuring proper engagement and disengagement of the pawls with the outer race.
Implementation Method 1
a spring that biases the top rear portion of the pawl
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
An overrunning clutch has a first race, a second race, a set of pawls between the first race and the second race and a set of springs between the first race and the second race, one spring for each pawl and each corresponding spring biasing the corresponding pawl into a position in which the first race and the second race are engaged with each other in a driving direction and are disengaged from each other in a free wheeling direction. Each spring is received in a spring receiving recess of one of the races and biases a rearward portion of the corresponding pawl radially inwardly into a pawl receiving recess of the race.