Shift Device Line Contact Reduces Pressure
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Solution Overview
Problem
Existing shift devices experience high contact pressure between the contact body and contact portion, leading to potential durability issues and inefficiencies in shifting operations.
Innovation Solution
A shift device design that utilizes line contact or surface contact between a contact body and a contact portion, facilitated by an urging force, to reduce contact pressure and enhance durability, allowing for consistent and efficient shifting between positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If point contact is used between detent member and engagement recesses, then the shift device achieves compact structure, but contact pressure becomes excessively high leading to durability issues
Solution Approach 1:
The patent transitions from point contact (zero-dimensional contact area) to line contact (one-dimensional contact area) or surface contact (two-dimensional contact area) between the detent member and engagement recesses. This dimensional expansion of the contact area distributes the urging force over a larger area, significantly reducing contact pressure while maintaining compact structure and improving durability.
Solution Approach 2:
The patent modifies the geometric parameters of the contact interface by changing the shape of the detent member from a spherical shape (point contact) to a cylindrical or planar shape (line or surface contact). This parameter change in contact geometry directly reduces contact pressure while preserving the functional requirements of the shift device.
2Stress or pressure
If line contact or surface contact is implemented, then contact pressure is reduced, but the complexity of ensuring consistent contact increases
Solution Approach 1:
The patent employs curved or rounded contact surfaces on the detent member and corresponding engagement recesses to ensure continuous line or surface contact during shift operations. The curved geometry naturally guides the contact points along a defined path, maintaining consistent contact pressure distribution and reducing complexity in ensuring reliable contact throughout the shifting range.
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 design achieves reduced contact pressure and increased durability by ensuring consistent line or surface contact, thereby improving the shifting operation and reducing the risk of mechanical failure.
Implementation Method 1
a contact body that is provided on the vehicle body side; and a contact portion that is provided on a shift body side, and that makes line contact or surface contact with the contact body due to an urging force
Implementation Method 2
the contact body and the contact portion make line contact or surface (face-to-face) contact. This enables the contact amount between the contact body and the contact portion to be increased, enabling the contact pressure between the contact body and the contact portion to be lowered
Data Source
AI summary
In a shift device, contact projections of a rotation cylinder make contact with side faces of recesses of an detent plate due to an urging force so as to urge a lever toward a shift position side. The contact projections make line contact with the side faces of the recesses. This enables the contact amount between the contact projections and the side faces of the recesses to be increased, enabling the contact pressure between the contact projections and the side faces of the recesses to be lowered.