Switch Device Knob Plunger Ball Joint Assembly

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Solution Overview

Problem

Existing switch devices for automotive applications face challenges in accommodating customer requirements while minimizing built-in space, particularly in terms of knob shape, housing shape, and the relative positioning of the switching component, leading to issues with plunger displacement and packaging constraints.

Innovation Solution

A switch device assembly featuring a plunger with a curved head and a ball joint connection to a knob, where the knob pivots around a rotational axis, allowing the plunger to move at a slower speed than the knob, thus compensating for potential course differences and maintaining a 1:1 ratio between the knob and plunger movement, while minimizing space usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the plunger is shifted relative to the knob to accommodate customer requirements, then adaptability is improved, but the device packaging space increases

Engineering Contradiction:
Improvecustomer requirements accommodationVSAvoidbuilt-in space
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The plunger head is given a curved surface with a ball joint connection that contacts the knob's groove. This curved interface allows the plunger to follow the rotational arc of the knob while maintaining linear motion, enabling the plunger to remain aligned with the switch regardless of knob rotation position, thus accommodating various design requirements without increasing space

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the plunger head by curving its surface and creating a ball joint connection. This parameter change allows the plunger to convert rotational motion into linear motion efficiently, maintaining a compact design while providing the necessary movement range to satisfy different customer requirements for switch positioning

Inventive Principle:
Principle #35Parameter changes

2Speed

If the plunger moves at the same speed as the knob, then movement synchronization is improved, but the course difference between knob actuation zone and plunger increases

Engineering Contradiction:
Improvemovement speedVSAvoidcourse ratio
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The curved ball joint connection between the plunger head and knob groove creates a mechanical advantage that naturally reduces the plunger's linear speed relative to the knob's rotational speed. This geometric relationship ensures that the plunger moves at a slower speed than the knob, compensating for the course difference and maintaining the required 1:1 course ratio between the middle of the knob and the plunger

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention transitions from direct linear coupling to a rotational-dim coupled system where the plunger moves along the groove's curved path. This dimensional change allows the plunger to follow the knob's rotation while maintaining precise control over its linear displacement, ensuring the course ratio is maintained despite speed differences

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 assembly effectively addresses customer requirements by maintaining design specifications, reducing packaging constraints, and ensuring secure and standardized movement, while allowing for compact device design.

Implementation Method 1

the knob's head not being in moving abutment against the plunger's head, said first contact point causing friction forces

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3404684B1An assembly comprising a switch device and a housing
Publication Date: 2023.06.21 DAV
  • EP3404684B1 patent drawingFigure 1
  • EP3404684B1 patent drawingFigure 2
  • EP3404684B1 patent drawingFigure 3

AI summary

An assembly (1) comprising a switch device (3) and a housing (5), said switch device being disposed relatively to the housing and comprising: - a switch (30), - a plunger (20), said plunger extending along a first longitudinal axis (A), - a knob (10) pivotally connected to the housing (5) such that the knob (10) pivots around a first rotational axis (C), said knob (10) having an actuation zone M which is remote from the first longitudinal axis (A), said knob (10) remaining in contact with said plunger (20) at any position of the knob (10), wherein a manual compression of the knob (10) in a first direction around the first rotational axis (C) on said actuation zone M causes the knob (10) to move at a first speed from a first position to a second position in which the plunger (20) actuates the switch (30), said manual compression of the knob (10) causing the plunger (20) to move at a second speed lower than the first speed of the knob (10).