Rotary Shifter Cam Lock for Auto Return to Park
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Solution Overview
Problem
Current shift-by-wire transmission shifters in vehicles face challenges in maintaining safety and design flexibility, particularly in the auto return-to-park operation, with limitations in cost efficiency, installation, and control over shifter components.
Innovation Solution
A rotary shifter apparatus featuring a drum cam with a track, a lock ring, and a rotor with undulating surfaces for gear positions, along with a feel positioner mechanism and rotor control mechanism, utilizing a spring-bias pin and lock pin to control engagement and disengagement, and an actuator system for automatic return-to-park functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotary shifter with auto return-to-park operation is implemented, then safety is improved by automatically returning the shifter to park position, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent combines the feel positioner mechanism and rotor control mechanism into a single integrated assembly that operates together during the auto return-to-park function. The lock ring with follower pin engages both the feel positioner spring and the rotor lock notch simultaneously, merging multiple control functions into one coordinated system rather than separate mechanisms.
Solution Approach 2:
The lock ring serves multiple functions: it controls the feel positioner spring engagement, controls the rotor lock notch engagement, and guides axial movement through the track. This multi-functional component reduces the need for separate control mechanisms, thereby improving safety without proportionally increasing device complexity.
2Ease of operation
If a lock ring with follower pin and spring-bias pin is used to control engagement and disengagement, then control over shifter components is improved, but device complexity increases
Solution Approach 1:
The spring-bias pin automatically engages and disengages the feel positioner spring based on the axial position of the lock ring, without requiring external control. The follower pin similarly self-regulates the rotor lock notch engagement through its interaction with the track geometry. This self-service mechanism provides precise control while minimizing the need for additional control components.
Solution Approach 2:
The follower pin acts as an intermediary between the drum cam track and the lock ring, translating axial movement into controlled engagement of the rotor lock notch. The spring-bias pin serves as an intermediary between the lock ring and the feel positioner spring, providing controlled engagement and disengagement. These intermediary elements enable precise control with simpler overall architecture.
3Manufacturing precision
If upper and lower track sections are used to control axial movement of the lock ring, then manufacturing precision is improved through defined engagement paths, but device complexity increases
Solution Approach 1:
The track is segmented into distinct upper and lower sections, each with specific geometric profiles that guide the follower pin through defined engagement paths. The upper track section controls engagement of the feel positioner spring, while the lower track section controls engagement of the rotor lock notch. This segmentation provides precise manufacturing tolerances for each section independently, improving overall precision without requiring a single complex track geometry.
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 enhances safety and design flexibility by ensuring the shifter automatically returns to the park position and locks it, maintaining safety and convenience while reducing costs and improving control over shifter components during the auto return-to-park function.
Implementation Method 1
A feel positioner mechanism includes at least one feel positioner spring with a spring loop operably engaging the undulating surface to hold the rotor in one of the P, R, N and D positions
Implementation Method 2
a drum cam rotatably supported on the base and having a track. A lock ring is movably supported on the drum cam for rotation and axial movement, the lock ring having a follower pin engaging the track
Data Source
AI summary
The present rotary shifter includes a rotary locking mechanism, a feel positioner mechanism, and a return-to-home-position (park) mechanism that causes the shifter/rotor to remain locked in park while the locking mechanism resets after the shifter is returned to park. The design allows any number of locking positions based on a height of the drum cam and a position of the follower. As illustrated, a dial-type rotor is moved into home position by pusher features on the drum cam and an actuator motor, while the feel positioner is disengaged, thus allowing for a smoother rotary movement. Once in the home (park) position, a lock ring (also called “follower”) is forced upwards by a spring (or other method) and rides on a track at a different height than the original, therefore keeping it engaged in the rotor until the drum cam rotates back to its locking position.