Appliance Knob Encoder Assembly with ERM Vibration Feedback
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Solution Overview
Problem
Traditional appliance knobs relying on mechanical detents for user feedback are prone to wear over time, necessitating a more durable and reliable positioning sensing mechanism.
Innovation Solution
A knob assembly featuring a rotatable shaft with a first circuit board and a fixed second circuit board, including an eccentric rotating mass motor to provide vibration and a sensor for accurate positioning data, along with a self-centering spring-return mechanism and conductive traces for electrical connection, forming an optical or inductive rotary encoder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical detents are used for user feedback, then user feedback is provided, but wear occurs over time
Solution Approach 1:
The patent replaces the traditional mechanical detent system with an encoder-based sensing system that uses optical, inductive, or capacitive fields instead of mechanical contact. The encoder detects knob position through non-contact means, eliminating wear from mechanical friction while maintaining positioning feedback functionality.
Solution Approach 2:
The patent introduces an encoder as an intermediary sensing mechanism between the knob and the control system. This encoder uses encoding portions on a first circuit board and corresponding sensors on a second circuit board to detect position without direct mechanical contact, serving as a mediator that eliminates wear while preserving the feedback function.
2Measurement precision
If encoder technology is implemented, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines the encoder components into an integrated assembly where the first circuit board with encoding portions and the second circuit board with sensors work together as a unified sensing system. This merging approach consolidates multiple functions (position sensing, signal generation, signal detection) into a compact integrated structure, reducing overall system complexity despite the advanced functionality.
Solution Approach 2:
The encoder assembly serves multiple functions simultaneously: it provides precise position sensing, generates positioning data through encoding portions, and can work with different types of encoders (optical, inductive, capacitive). The first and second circuit boards together perform both signal generation and detection, making the system multi-functional and reducing the need for separate components.
3Manufacturing precision
If circuit boards are positioned close together, then encoder precision is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent divides the encoder system into two separate circuit boards (first and second) that can be manufactured and tested independently before final assembly. The encoding portions are fabricated on the first circuit board while the sensors are mounted on the second circuit board, allowing for modular manufacturing and quality control while achieving the required precision when assembled.
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 provides durable, accurate, and reliable knob positioning with haptic feedback, reducing wear and enhancing user experience by leveraging advanced sensor technology for precise control.
Implementation Method 1
the encoding portion includes a codewheel, the sensor includes an optical encoder, and the codewheel and optical encoder form an optical rotary encoder
Implementation Method 2
the encoding portion and sensor are components of and form an inductive or capacitive rotary encoder
Implementation Method 3
an eccentric rotating mass (ERM) motor mounted to the rotatable, first circuit board with a shaft of the ERM motor perpendicular to the rotatable shaft of the knob in which the ERM motor is configured to produce and transfer vibration to the rotatable shaft of the knob
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A knob assembly is provided that includes a knob having a rotatable shaft, a rotatable first circuit board rigidly attached to the rotatable shaft, and a fixed second circuit board positioned near the first circuit board. The first circuit board includes an encoding portion configured to provide positioning data of the knob, and an eccentric rotating mass (ERM) motor mounted to the rotatable, first circuit board with a shaft of the ERM motor perpendicular to the rotatable shaft of the knob. The ERM motor is configured to produce and transfer vibration to the rotatable shaft of the knob. The second circuit board includes a sensor configured to determine a position of the first circuit board and thereby the knob at least in part from the positioning data provided by the encoding portion.