Haptic Solenoid Noise Suppression via Foam Bumper
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Solution Overview
Problem
Existing haptic solenoids used in automotive environments produce audible clicking noises during vibrational bursts, which are undesirable in quiet settings like cars and can interfere with user-selected electronic sounds.
Innovation Solution
A novel haptic solenoid system with a monolithic plastic frame and strategically placed pole pieces, using bumpers with skirt designs for noise suppression, allowing for efficient vibrational feedback without audible noise, designed for automotive use with touch screens and other applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If haptic solenoids are used to provide tactile feedback on touch screens, then physical buttons can be eliminated and cost saved, but audible clicking noises are generated that interfere with user-selected electronic sounds in automotive environments
Solution Approach 1:
A foam bumper material is introduced as an intermediary element between the solenoid plunger and the magnetic circuit. This foam bumper absorbs the impact energy and dampens the mechanical shock, thereby eliminating the audible clicking noise while still allowing the haptic feedback function to operate effectively
Solution Approach 2:
The harmful clicking noise is converted into a beneficial dampening effect by using the foam bumper to absorb the impact energy. The foam material transforms the mechanical shock that causes noise into controlled deformation, eliminating the harmful acoustic output while maintaining the haptic feedback mechanism
2Speed
If the solenoid plunger moves rapidly to generate vibration pulses, then tactile feedback is effective, but audible clicking noise is produced
Solution Approach 1:
The foam bumper serves as a mediator between the rapidly moving plunger and the magnetic circuit, allowing the plunger to maintain its high-speed movement for effective vibration generation while the foam absorbs the impact shock that would otherwise produce audible clicking noise
3Reliability
If the solenoid is rigidly mounted to provide stable vibration, then vibration transmission is effective, but the clicking noise is amplified
Solution Approach 1:
The foam bumper is positioned as an intermediary element that decouples the rigid mounting structure from the noise generation source. It allows the solenoid to remain rigidly mounted for stable vibration transmission while the foam material absorbs the impact shocks that would be amplified by the rigid structure and produce audible clicking noise
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 system provides tactile feedback without noise interference, enabling the elimination of physical buttons on dashboards and improving user experience through effective vibration transmission and noise attenuation.
Implementation Method 1
The present invention utilizes a novel haptic solenoid that works on the solenoid principle
Implementation Method 2
Powering the unit on and off alternately closes and opens the air gap between the two pole pieces. This limited motion produces a vibration pulse with each power cycle
Implementation Method 3
The plastic frame serves as the resilient restoring force for the solenoid
Implementation Method 4
it is important that noise be suppressed. This is accomplished through the use of a bumper on one or both poles of the solenoid
Data Source
AI summary
A supporting surface and a touch screen member mounted to a plastic frame having a first vibration transmitting slot and at least two mounting slots. A pair of similar L-shaped poles is mounted in the frame in juxtaposition to define gaps between them. One of the poles constitutes a stationary pole and the other of the poles constitutes a movable pole. A winding is mounted on the stationary pole. The frame defines a vibration transmitting slot, and the touch screen member is attached to the frame by a tab that is press fitted into the vibration transmitting slot so that vibrations created by the movable pole can be transmitted via the vibration transmitting slot to the touch screen member. The additional slots defined by the frame and tabs defined by the supporting surface mutually coact for mounting the frame to the supporting member in a stationary position.