Throttle Gear Lever Alignment for Rotational Angle Detection

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Solution Overview

Problem

Conventional intake air quantity control devices with rotational angle detectors suffer from output errors due to deviations in the fitting portion, increased component count, and space constraints, leading to instability and bulkiness.

Innovation Solution

The design incorporates a fan-shaped throttle gear with a through-hole and a lever that fits into the hole, reducing the number of components and minimizing the orthogonal length, while the rotational angle detector is integrated into a cover with a rotor aligned with the throttle shaft axis, eliminating the need for additional fitting space and reducing clearance influences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a flat portion is provided at the end portion of a throttle shaft for rotational angle detection, then the rotational angle can be detected by fitting with a supporting hole, but output errors arise when the throttle shaft axis deviates from the rotational angle detector axis

Engineering Contradiction:

Improverotational angle detection accuracyVSAvoidoutput stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A lever is introduced as an intermediary component between the throttle shaft and the rotational angle detector. The lever rotates about an axis coincident with the throttle shaft axis and transmits rotational position information to the detector, eliminating direct alignment requirements and preventing output errors from axis deviation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The direct mechanical fitting between the throttle shaft and rotational angle detector is replaced with an indirect mechanical transmission system using the lever. This substitution allows the detector axis to be positioned independently from the throttle shaft axis while maintaining accurate rotational angle detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Volume of moving object

If the radius of the fitting portion between the throttle shaft and rotational angle detector is made small, then the device size is reduced, but the output error becomes large with respect to deviation at the fitting portion

Engineering Contradiction:

Improvedevice sizeVSAvoidoutput error magnitude

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The lever is positioned in a different spatial dimension (rotating about the throttle shaft axis) rather than requiring radial extension from the shaft. This dimensional repositioning allows for a larger effective radius without increasing the radial footprint of the device, thereby reducing output errors while maintaining compact size

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If a lever portion is provided at the tip of the throttle shaft for fitting, then the throttle body and rotational angle detector can be connected, but the number of components increases

Engineering Contradiction:

Improveassembly capabilityVSAvoidnumber of components

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The lever is merged with the rotational angle detector as an integrated component rather than being a separate attachment. The lever is positioned within the detector housing and rotates about the throttle shaft axis, combining the functions of connection and detection while reducing the total component count

Inventive Principle:

Principle #5Merging (Combining)

4Adaptability or versatility

If the fitting portion is rotated in a direction protruding to the opposite side of the motor, then the throttle body can accommodate the rotation, but the throttle body gets larger to ensure rotational radius

Engineering Contradiction:

Improverotational movement capabilityVSAvoidthrottle body size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The lever rotates about the throttle shaft axis (longitudinal dimension) rather than requiring radial movement in the plane perpendicular to the shaft. This dimensional change allows rotational movement without increasing the radial dimensions of the throttle body, maintaining compact size while enabling necessary rotation

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS8671910B2Intake air quantity control device for internal combustion engine

Publication Date: 2014.03.18 MITSUBISHI ELECTRIC CORP

AI summary

In the intake air quantity control device for an internal combustion engine, in which an open area formed at a portion of the throttle body is encapsulated by a cover including a rotational angle detector, a throttle gear is fixed to a throttle shaft for rotatably supporting a throttle valve and has a fitting portion at a portion of the throttle gear. The rotational angle detector includes a rotor that is rotatably supported and arranged in the cover in such a way that an axis of the rotor is identical to an axis of the throttle gear, and a lever that is provided at a portion of the rotor, which is faced to the throttle shaft, and engaged to a wall portion of the throttle gear at a portion of the lever.