Rotating body dynamic quantity measuring device and system

Abstract

A single crystal semiconductor including a Wheatstone bridge circuit formed of an impurity diffusion layer whose longitudinal direction is aligned with a particular crystal orientation is connected to a rotating body. A rotating body dynamic quantity measuring device and a system using the measuring device are fatigue- and corrosion-resistant because of the single crystal semiconductor used and are not easily affected by temperature variations because of the bridge circuit considering a single crystal anisotropy.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to a measuring system to detect dynamic quantities of a rotating body. [0002] Dynamic quantities of a rotating body, particularly torques, have conventionally been measured by attaching a wire strain gauge to the rotating body and measuring a change in a resistance of a fine metal wire of the gauge. However, since a thin film easily develops a high cyclic fatigue, it is difficult for the wire strain gauge to maintain reliability for a long period when used in applications that cause high cyclic deformations, such as measuring strains and torques of rotating shafts. That is, the wire strain gauge has not been able to be used in applications that affect human lives and thus require very high reliability, such as automotive drive axels. Further, in forming a Wheatstone bridge for temperature correction four wire strain gauges need to be attached and their possible peeling and damage pose a problem of a degraded reliabilit...

AI Technical Summary

Benefits of technology

[0006] With this invention, since a semiconductive single crystal is used, the device is not fatigued by a high cyclic load. It is therefore possible to secure a sufficient reliability for a long period of use. Further, since the device is formed of a single crystal and has no grain boundary, it is not corroded under a corrosive environment, allowing for a highly reliable measurement.

[0007] Further, since the rotating body dynamic quantity measuring device using a single crystal semiconductor is very small and light in weight, if it is attached to a rotating body, it is subjected to only a small centrifugal force resulting from its own mass and thus requires no special high-strength jointing method, which in turn improves reliability. The single crystal semiconductor in particular can be manufactured into a very small size with high precision by using the semiconductor manufacturing technique. Therefore, there is no need for a process to re-establish a shaft balance after the measuring device is mounted.

Problems solved by technology

However, since a thin film easily develops a high cyclic fatigue, it is difficult for the wire strain gauge to maintain reliability for a long period when used in applications that cause high cyclic deformations, such as measuring strains and torques of rotating shafts.

That is, the wire strain gauge has not been able to be used in applications that affect human lives and thus require very high reliability, such as automotive drive axels.

Further, in forming a Wheatstone bridge for temperature correction four wire strain gauges need to be attached and their possible peeling and damage pose a problem of a degraded reliability.

Also since a metal thin film is easily corroded, the wire strain gauges could not be used for a long period under corrosive environments or environments containing water.

This, however, tends to make the device complex, large and heavy.

When it is attached to a shaft, the device can easily fall because of an increased centrifugal force acting on it.

That is, although it is possible to take time and labor to perform test measurements using the wire strain gauges, they cannot safely be used for applications that require reliability.

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