Rotation Input Device Planetary Gear and Magnetic Detection

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Solution Overview

Problem

Existing rotation input devices face challenges in accurately detecting the rotation angle and direction of an operation knob, particularly when the electromagnetic brake is engaged, leading to difficulties in determining the correct rotation direction and incomplete unlocking of the operation knob.

Innovation Solution

A rotation input device configuration that includes a rotary operation member, a first rotary member, a rotation detecting unit, a holding unit, a braking unit, and a planetary gear support, allowing the operation member and second rotary member to rotate in unison while applying drag, and releasing the braking unit when the rotation direction is reversed, enabling sensitive detection of rotation angle and direction changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electromagnetic brake prevents the drive shaft from rotating, then the operation range and operation limits can be recognized, but the rotation direction cannot be determined and the operation knob cannot be unlocked when rotated in the opposite direction by a small angle

Engineering Contradiction:

Improveoperation range recognitionVSAvoidrotation direction determination

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The drive shaft is segmented into two independent rotational components: one that rotates with the operation knob and another that rotates independently to detect rotation direction. This segmentation allows the brake to lock the drive shaft for operation range recognition while the independent component continues to detect rotation direction changes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A magnetic field is introduced as an intermediary between the operation knob and the detection system. The magnetic field can detect rotation direction changes even when the mechanical brake is engaged, serving as a mediator that transmits rotation information without requiring mechanical movement of the entire drive shaft.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the operation knob is completely locked by the electromagnetic brake, then the tactile barrier is provided, but it becomes difficult to determine the direction in which the operation knob is to be rotated

Engineering Contradiction:

Improvetactile barrier provisionVSAvoidrotation direction detection

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The mechanical detection system is replaced with a magnetic field-based detection system. Instead of relying on mechanical movement of the drive shaft to detect rotation direction, the magnetic field detects changes in rotation direction through electromagnetic signals, allowing detection even when the mechanical brake is fully engaged.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the rotary encoder detects the angle and direction of rotation, then the operation can be accurately recorded, but the detection sensitivity is insufficient when the brake is engaged

Engineering Contradiction:

Improverotation angle detectionVSAvoiddetection sensitivity

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The magnetic field serves as an intermediary that enhances detection sensitivity by providing a direct electromagnetic coupling between the operation knob and the detection system. This intermediary allows the rotary encoder to detect even small rotation angles and direction changes with high sensitivity, independent of the brake's mechanical engagement state.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 device provides high sensitivity in detecting rotation angle and direction changes, ensuring accurate operation and reliable prevention of rotation without component damage, enhancing the operation feeling and reliability of the input device.

Implementation Method 1

a planetary gear support configured to rotate concentrically with and in unison with the rotary operation member and rotatably support a planetary gear, an inner teeth row, provided for the second rotary member, configured to mesh with the planetary gear, and an outer teeth row, provided for the first rotary member, configured to mesh with the planetary gear

Methodology Applied

Scientific EffectPlanetary gear mechanism: Epicyclic Gearing

Implementation Method 2

a braking unit for stopping the rotation of the second rotary member when an output of the rotation detecting unit exceeds an operation range of the rotary operation member

Methodology Applied

Scientific EffectElectromagnetic brake: Friction

Data Source

PatentUS8866643B2Rotation input device

Publication Date: 2014.10.21 ALPS ALPINE CO LTD

AI summary

In a rotation input device, a planetary carrier, connected to an operation knob, rotatably supports a planetary gear which meshes with an outer teeth row provided for a sun gear, to which an output shaft is secured, and also meshes with an inner teeth row provided for an outer gear. A plunger provided for the sun gear is in elastic contact with a recess cam provided for the outer gear. A solenoid unit prevents rotation of the outer gear in accordance with an output of a magnetic sensor which faces a magnet provided for the output shaft.