Polystable Gear Shifter CAM Mechanism for Silent Gear Seeking
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Solution Overview
Problem
Existing gear shifters lack the ability to gear seek without motor overload during obstructions and require high-strength, costly components with limited tactile feedback and inefficient locking mechanisms, leading to potential safety concerns and increased size and weight.
Innovation Solution
A gear seeking shifter with a rotatable base and CAM components, featuring retractable gate and detent pawls, a lock mechanism with spring-loaded plungers, and a sensor system to manage gear positions without motor overload, allowing variable shift distances and silent operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If standard detent profile and spring are used in gear seeking assembly, then gear seeking ability is provided, but loud noises occur during detent jumping and tight balance between shift effort and motor driving effort is required
Solution Approach 1:
The patent extracts the detent pawl from the traditional detent profile mechanism. Instead of using a spring-loaded detent system that jumps over detents, the invention uses a cam mechanism that continuously guides the shift lever along a predetermined path, eliminating the sudden detent engagement that causes loud noises.
Solution Approach 2:
The patent replaces the traditional mechanical detent profile and spring system with a cam-based guidance mechanism. The cam profile geometrically constrains the shift lever movement, substituting the need for springs and detents with a deterministic geometric path, thereby eliminating noise from detent engagement.
2Extent of automation
If polystable knob style gear seeking shifter is used, then gear seeking is enabled, but equal angular positions are required between all gear positions which limits tactile feedback
Solution Approach 1:
The patent applies local quality by allowing different angular positions and spacing between gear positions on the cam mechanism. Each gear position can be optimally positioned to provide distinct tactile feedback, rather than requiring uniform angular spacing. This enables the system to maintain gear seeking automation while providing variable tactile cues for different gear transitions.
3Reliability
If high strength parts and increased part counts are used to manage gear seeking system, then reliability is improved, but mass, cost and size of shifter assembly increase
Solution Approach 1:
The cam mechanism serves multiple functions simultaneously: it guides the shift lever through the correct sequence of gear positions, provides tactile feedback through its profile, enables the gear seeking automation, and replaces the need for separate detent springs and pawls. This multi-functionality reduces part count while maintaining reliability.
Solution Approach 2:
The patent merges the gear seeking control mechanism with the shift lever guidance mechanism into a single cam component. This integration eliminates the need for separate motors, detent systems, and guidance mechanisms, reducing overall assembly mass, cost, and complexity while maintaining functional reliability.
4Ease of operation
If solenoid locking mechanism is used, then locking functionality is provided, but large size and high cost are required for proper response time and travel
Solution Approach 1:
The patent replaces the solenoid-based locking mechanism with a cam-based mechanical guidance system. The cam profile inherently guides the shift lever to the correct position without requiring active solenoid actuation, reducing the locking mechanism size and cost while maintaining functional reliability.
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
Enables gear seeking without motor overload, reduces noise and component costs, provides tactile feedback, and enhances safety by allowing precise control and silent operation between gear positions.
Implementation Method 1
spring loaded and displaceable plungers which are normally spring biased into a locked or engagement position
Implementation Method 2
A CAM component is slaved to the rotatable base and is driven by a gear seeking motor... a first profile configured to retract the gate pawl and a second profile configured to engage the detent pawl
Data Source
AI summary
A gear seeking shifter having a housing containing a shift lever with a depressible inner push rod. A CAM component is rotatably supported to a base of the shift lever and is driven by a gear seeking motor. An upwardly biased gate pawl is secured to the inner push rod into contact with any of a PRND shifter position gates configured along an opposing underside of said housing. At least one detent pawl is supported within the housing in biasing contact with a detent plate configured upon an opposing inside surface of the housing. The CAM component, upon being rotated by the motor, includes each of a first profile for retracting the gate pawl and a second profile for engaging and inwardly displacing the detent pawl away from contact with the detent plate to permit the CAM component to rotate the shift lever to a desired gear position.