JP2004309304A - Detection gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove influence of a disturbance magnetic flux on the output of a magnetic sensor by forming a part by a non-magnetic material. <P>SOLUTION: This detection gear has constitution wherein the gear 1 comprises a small-diameter body 4 on a rotating shaft 3 side and a larger-diameter gear body 5 than the small-diameter body 4, and the small-diameter body 4 comprises the non-magnetic material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a detection gear, and in particular, to a novel improvement for reducing the magnetic influence on a signal component detected by a magnetic sensor by using a gear having two members, a small-diameter body made of a non-magnetic material and a gear body made of a magnetic material. About.
[0002]
[Prior art]
Conventionally, this kind of detection gear is an in-house product, so patent documents and the like are not particularly disclosed, but a gear made of a magnetic material is provided on the rotating shaft.
[0003]
[Problems to be solved by the invention]
Since the conventional detection gear is configured as described above, the following problems exist.
That is, as shown in FIG. 2, when the magnetic sensor 2 is disposed near the outer periphery of the gear 1 and a magnetic change due to rotation of the gear 1 is detected by the magnetic sensor 2, the entire gear 1 is formed of a magnetic material. Therefore, disturbance magnetic flux is generated in the state shown by the solid line in FIG. 2 and passes through the magnetic sensor, thereby adversely affecting the formation signal of the magnetic sensor 2.
[0004]
The present invention has been made in order to solve the above-described problems. In particular, a gear is formed of a small-diameter body made of a non-magnetic material and a gear body made of a magnetic material, and given to a signal component detected by a magnetic sensor. It is an object of the present invention to provide a detection gear configured to reduce magnetic influence.
[0005]
[Means for Solving the Problems]
The detection gear according to the present invention is a detection gear in which a gear provided on a rotating shaft is positioned near a magnetic sensor to perform magnetic detection, wherein the gear has a small-diameter body on the rotating shaft side and the small-diameter body. The gear body has a larger diameter, the small diameter body is made of a non-magnetic material, and the gear body is made of a magnetic material.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a detection gear according to the present invention will be described with reference to the drawings.
In FIG. 1, a gear indicated by reference numeral 1 is a gear. The gear 1 is directly fixed to the rotating shaft 3 and formed of a small-diameter body 4 made of a non-magnetic material, and a magnetic material provided on the peripheral surface of the small-diameter body 4. The gear 5 is formed.
Therefore, the small-diameter body 4 is provided on the rotating shaft 3 side and has a smaller diameter than the gear body 5.
[0007]
The gear 1 having the two-body structure shown in FIG. 1 is used as shown in FIG. 2, and a magnetic sensor 2 is disposed near the outer periphery of the gear 1.
Therefore, the disturbance magnetic flux G passing through the rotating shaft 3 is reduced by the presence of the small diameter body 4 made of the non-magnetic material of the gear 1 (that is, due to the magnetic resistance of the small diameter body 4), and as shown by the dotted line, the disturbance magnetic flux G Goes outside the gear 1 and does not pass through the magnetic sensor 2, so that the influence on the signal component detected by the magnetic sensor 2 can be reduced.
[0008]
【The invention's effect】
Since the detection gear according to the present invention is configured as described above, the following effects can be obtained.
In other words, the gear is composed of a small-diameter body and a large-diameter gear body, and the small-diameter body is made of a non-magnetic material, so that the magnetic resistance to disturbance magnetic flux increases, and the influence of the disturbance magnetic flux on the output signal of the magnetic sensor. Can be prevented, and the output of the magnetic sensor can be stabilized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a gear according to the present invention.
FIG. 2 is an explanatory diagram showing a flow state of disturbance magnetic flux according to the present invention and a conventional one.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gear 2 Magnetic sensor 3 Rotation shaft 4 Small diameter body 5 Gear body

Claims (1)

In a detection gear in which a gear (1) provided on a rotating shaft (3) is positioned near a magnetic sensor (2) to perform magnetic detection,
The gear (1) includes a small-diameter body (4) on the rotation shaft (3) side and a gear body (5) having a larger diameter than the small-diameter body (4), and the small-diameter body (4) is non-magnetic. The detection gear is made of a material, and the gear body (5) is made of a magnetic material.

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