Rotary Switch Cam Mechanism for Haptic Feedback
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Solution Overview
Problem
Rotary switches in automotive steering wheel column integrated modules lack effective recognition of direction of rotation and discrete parameter changes with perceivable haptic responses, and they often have angular limits, are not compact, and are costly to manufacture and assemble.
Innovation Solution
A rotary switch assembly with a slider that maintains equilibrium position using radial protrusions and spring plungers, allowing for angular displacement conversion into axial displacement, providing a haptic response and compact design without angular limits, and enabling cost-effective and simple manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If oblique cams are employed to convert rotational movement into sliding movement, then the switch can control vehicle components, but the device lacks recognition of direction of rotation and discrete parameter changes with perceivable haptic responses
Solution Approach 1:
The control ring is divided into multiple segments with radial protrusions at different angular positions. Each radial protrusion corresponds to a specific rotational position and interacts with the slider to generate discrete haptic responses. This segmentation allows the system to recognize different directions of rotation and discrete parameter changes without requiring a complex overall structure.
Solution Approach 2:
The cam surfaces on the slider and radial protrusions on the control ring are designed with specific local geometric properties. The cam surfaces are shaped to provide asymmetric haptic feedback depending on the direction of rotation, enabling the system to distinguish between clockwise and counter-clockwise rotations through localized surface interactions rather than requiring complex global structural changes.
2Ease of operation
If spring plungers and radial protrusions are used to provide haptic response and maintain equilibrium, then discrete parameter changes are recognized, but the device complexity increases
Solution Approach 1:
The spring plunger mechanism is integrated directly into the slider assembly, and the radial protrusions are formed as part of the control ring structure. This merging of functions reduces the number of separate components while maintaining the haptic response capability. The equilibrium position is maintained through the combined action of the spring plunger and the geometric configuration of the cam surfaces, eliminating the need for additional separate mechanisms.
3Productivity
If the slider is constrained to move between radial protrusions with cam surfaces, then angular displacement is converted to axial displacement efficiently, but the manufacturing precision requirements increase
Solution Approach 1:
The cam surfaces are designed with asymmetric profiles that are optimized for unidirectional force transmission. The asymmetric geometry allows for efficient conversion of angular displacement to axial displacement while providing built-in mechanical guidance that tolerates typical manufacturing variations. The asymmetric shape ensures that the slider is pushed in the correct direction during rotation while minimizing sensitivity to precise dimensional tolerances.
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 recognition of rotation direction and discrete parameter changes with a perceivable haptic response, maintains a compact design, and simplifies manufacturing and assembly, ensuring efficient operation without angular limits.
Implementation Method 1
said radial protrusion of said slider or said radial protrusions of said control ring has/have a form of a cam having two angularly external surfaces slanted at the same orientation with respect to said axis of rotation such that an angular displacement of said control ring is converted into an axial displacement of said slider
Implementation Method 2
said slider is provided with means for restoring the slider equilibrium position along said axis of rotation
Data Source
Figure 1~3
Figure 4~5a
Figure 6a~7d
AI summary
The invention relates to a rotary switch assembly (1a), in particular of a steering wheel column integrated module of an automotive vehicle, comprising a support member (2), a control ring (4) held rotationally by said support member (2), a slider (5) disposed slidably along the axis (A) of rotation of said control ring (4) and cooperating with an activating member (3) to generate electrical signals. In order to recognise direction of rotation of said control ring (4), as well as to provide a discrete change of the parameter controlled by the switch assembly (1a) with fittingly perceivable haptic response indicating if such a change has been effected said slider (5) is provided with means (51, 25) for restoring the slider (5) equilibrium position along said axis of rotation (A), said control ring (4) is provided with a number of substantially equiangularly disposed radial protrusions (42a, 42b), said slider (5) is provided with a radial protrusion (52a, 52b) that extends in an area of a circumference defined by said radial protrusions (42a, 42b) of said control ring (4), in the slider (5) equilibrium position remains between two adjoining radial protrusions (42a, 42b) of said control ring (4), and cooperates with said radial protrusions (42a, 42b) of said control ring (4), wherein said radial protrusion (52a) of said slider (5) or said radial protrusions (42b) of said control ring (4) has/have a form of a cam (8) having two angularly external surfaces (81, 82) slanted at the same orientation ( α1, α2 ) with respect to said axis of rotation (A) such that an angular displacement of said control ring (4) is converted into an axial displacement of said slider (5).