Low Backlash Multimode Clutch with Curved Engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing one-way clutches in automotive transmissions require backlash to switch modes, leading to driveline jolts and inefficiencies in torque transmission in both rotational directions.
Innovation Solution
A low-backlash multimode clutch design featuring an annular inner and outer race with a one-way bearing and pivotably mounted pawls, where actuator elements apply inward forces to engage or disengage the clutch with minimal or no backlash, using radiused pawls and slots to prevent rotational movement in one direction while allowing it in the other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional one-way clutches are used with pawls and springs, then torque translation in one direction is achieved, but backlash occurs during mode switching causing driveline jolts
Solution Approach 1:
The patent applies curvature by replacing the conventional pawl with a curved surface engagement mechanism. The first surface of the movable race has a curved engagement surface that contacts a corresponding curved surface on the stationary race, eliminating the need for pawls and springs. This curved surface geometry allows for smooth engagement and disengagement without backlash, thereby preventing driveline jolts while maintaining reliable torque transmission.
Solution Approach 2:
The patent extracts and removes the traditional pawl and spring components from the clutch mechanism. By eliminating these elements that inherently require backlash for operation, the invention achieves a cleaner design that can operate without the harmful jolts caused by mode switching backlash, while still achieving the necessary torque translation functionality.
2Adaptability or versatility
If selectable one-way clutches are used to switch modes, then torque direction control is achieved, but backlash during switching reduces operational smoothness
Solution Approach 1:
The curved engagement surfaces on the movable and stationary races enable smooth transitions between torque translation modes. The geometry of the curved surfaces is designed to guide the engagement and disengagement process, allowing the clutch to switch between different torque directions without abrupt movements or backlash, thereby maintaining operational smoothness while providing versatile torque direction control.
Solution Approach 2:
The patent employs a movable race that can dynamically shift positions to achieve different engagement states. This dynamic capability allows the clutch to adaptively control torque direction by moving the race along the curved engagement surfaces, enabling smooth transitions between modes without the backlash problems associated with static or rigid switching mechanisms.
3Device complexity
If conventional clutch designs are used, then structural simplicity is maintained, but backlash causes energy loss and inefficiency
Solution Approach 1:
By removing the pawl and spring components, the patent eliminates the sources of backlash that cause energy loss. Although this may seem to increase complexity, the resulting direct curved surface contact between the races creates a more efficient torque transmission path with minimal energy loss, while the overall structure remains relatively simple without unnecessary intermediate components.
Solution Approach 2:
The curved engagement surfaces create a more efficient contact geometry compared to conventional pawl engagements. This curvature allows for better load distribution and reduced sliding friction during engagement and disengagement, thereby minimizing energy loss while maintaining a simple two-race structure without additional complex mechanisms.
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 solution enables torque translation in either rotational direction with reduced or eliminated backlash, minimizing driveline jolts and improving operational smoothness.
Implementation Method 1
a one-way bearing allowing relative rotation of the races in a first direction but not a second direction
Implementation Method 2
One or more actuator elements are included and are configured to selectively apply an inward force to the pawls
Implementation Method 3
using radiused pawls and slots to prevent rotational movement in one direction while allowing it in the other
Data Source
AI summary
A low-backlash multimode clutch includes a one-way bearing allowing rotation in a first direction as well as a number of actuatable pawls in one race and a number of receiving slots having engagement faces in the other race. The engagement faces are tilted such that when the pawls are actuated, any torque applied in the first direction tends to force the pawls outward but the pawls are retained inward, such as by actuator rods. In this way, the one-way clutch may be selectively locked and unlocked with zero backlash against the one-way bearing.