JPH04184258A - Detection body for magnetic rotation sensor - Google Patents

Abstract

PURPOSE:To obtain the title detection body capable of ensuring stable detection characteristics by directly forming recessed and protruding parts to the outer peripheral surface of the rotary shaft of a magnetic body. CONSTITUTION:Recessed and protruding parts, for example, teeth 13a are directly formed to the outer peripheral surface of the end part of the rotary shaft 12 of a magnetic body. A magnetic rotation sensor 4 is arranged in the direction crossing the shaft 12 at a right angle. Further, teeth 13a' may be directly formed to the end surface 12a' of a shaft 12'. In this case, the sensor 4 is arranged at the position opposed to the end surface 12a'. Further, the sensor 4 may be formed as a sensor 4' equipped with a plurality of magnetoelectric converter elements DT coaxially arranged outside the teeth 13a. Since the teeth 13a are directly formed on the rotary shaft 12, assembling work can be reduced and, since the eccentricity of the teeth 13a to the rotary shaft 12 can be reduced, the lowering of detection accuracy can be prevented.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a detected object for a magnetic rotation sensor, and more specifically, to a magnetic rotation sensor used to measure the rotational speed, rotational displacement, etc. of a rotating shaft. This invention relates to a detected object for a sensor.

(Prior Art) A conventional detection object 1 for a magnetic rotation sensor will be described with reference to FIG.

A detected object 1 for a magnetic rotation sensor shown in the figure has a rotating shaft 2 fitted with a gear 3 having equally spaced teeth 3a.

A magnetic rotation sensor 4 is disposed close to the gear 3 to detect the rotational speed, rotational displacement, etc. of the rotating shaft 2.

FIG. 5 shows a principle diagram of rotation detection by the magnetic rotation sensor 4. As shown in FIG. The magnetic rotation sensor 4 includes a magneto-electric conversion element D, such as a Hall IC, which outputs an electric signal according to the magnetic flux density B.
DT, and a permanent magnet M that applies a magnetic field to the element DT.

As shown in the figure, the magnetic rotation sensor 4 is arranged near the outer periphery of the gear H with a gap G between them, and when the gear H rotates in either direction, the magnetic flux imparted to the magnetoelectric transducer DT is caused by the displacement of the teeth Ha. The density B varies, and in accordance with this magnetic flux density B, a pulsed electrical signal is obtained from the magnetoelectric transducer DT. The rotational speed, rotational displacement, etc. of the gear H are detected based on this pulsed electric signal.

(Problems to be Solved by the Invention) As described above, in the conventional detection object 1 for a magnetic rotation sensor, a gear is fitted onto a shaft, which takes time to assemble, and if the fitting accuracy is poor, the gear may become uneven. There was a problem in that the detection accuracy deteriorated due to overconsumption.

Therefore, the present invention has been made in view of the above circumstances, and
It is an object of the present invention to provide a detected object for a magnetic rotation sensor that can ensure stable detection characteristics.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention is characterized in that unevenness is directly formed on the outer peripheral surface of the rotating shaft of the magnetic material. Moreover, the unevenness may be directly formed on the inner circumferential surface of the rotating cylinder of the magnetic material, or the unevenness may be directly formed on the rotating shaft of the magnetic material or the end surface of the rotating cylinder.

(Function) According to the object to be detected for a magnetic rotation sensor having the above configuration, by forming the unevenness directly on the rotating shaft or the rotating tube, assembly work can be omitted and the unevenness on the rotating shaft or rotating tube can be formed directly. Eccentricity can be reduced and detection accuracy can be prevented from deteriorating.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a perspective view of essential parts of a detection object 10 for a magnetic rotation sensor according to a first embodiment of the present invention.

The object to be detected 10 has irregularities, for example, teeth 13a, which are formed directly on the outer peripheral surface of the end side of a rotating shaft 12 made of a magnetic material at equal intervals. The magnetic rotation sensor 4 is arranged in a direction perpendicular to the axis 12, as shown in the figure.

Further, the tooth 13a' is located at the end surface 1 of the shaft 12' as shown in FIG.
It may also be formed directly on 2a'. In this case, sensor 4 is
It is arranged at a position facing the end surface 12a'. Further, the sensor 4 includes a plurality of magnetoelectric transducers DT and the like coaxially arranged outside the teeth 13a as shown in FIG.
You can also use it as

According to the detected object 10 of the first embodiment configured in this way, since the teeth 13a are formed directly on the rotating shaft 12, assembly work can be reduced, and the teeth 13a are formed directly on the rotating shaft 12. Since the eccentricity of the sensor can be reduced, a decrease in detection accuracy can be prevented.

FIG. 4 shows a perspective view of a main part of a detection object 20 for a magnetic rotation sensor according to a second embodiment of the present invention.

The object to be detected 20 includes a rotary cylinder 22 and an inner circumferential surface on the end side of the rotary portion 2, in which irregularities such as teeth 23a are directly formed at equal intervals. Further, the magnetic rotation sensor 4 is arranged inside the rotary cylinder 22 as shown in the figure.

According to the detected object 20 of the second embodiment configured in this way, the teeth 23a and the sensor 4 are arranged inside the rotary tube 22, so even if the sensor is used in a bad environment with a lot of dust etc. 4 can be prevented from being crushed and undetectable due to external factors such as dust.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be variously modified without changing the gist thereof.

[Effects of the Invention] According to the invention described in claim 1 detailed above, since the unevenness is formed directly on the rotating shaft, it is possible to reduce assembly work and reduce the eccentricity of the unevenness with respect to the rotating shaft. Therefore, it is possible to provide an object to be detected for a magnetic rotation sensor that can prevent a decrease in detection accuracy and ensure detection characteristics.

Further, according to the invention as claimed in claim 2, since the unevenness is directly formed on the inner circumferential surface of the rotary cylinder, in addition to the effect as stated in claim 1, it is stable even when used in a bad environment with a lot of dust, etc. Detection characteristics can be ensured.

Furthermore, according to the invention set forth in claim 3, since the unevenness is directly formed on the end face of the object to be detected, in addition to the effect set forth in claim 1, the sensor can be arranged in the axial direction and miniaturization in the radial direction can be achieved. .

[Brief explanation of drawings]

FIG. 1 is a perspective view of a main part of a detected object for a magnetic rotation sensor according to a first embodiment of the present invention, FIG. 2 is a perspective view of a main part showing another example of this detected object, and FIG. 1 is a sectional view of a main part showing another example of the sensor shown in FIG. 1, FIG. 4 is a perspective view of a main part of a detected object for a magnetic rotation sensor according to a second embodiment of the present invention, and FIG. FIG. 6, which is a diagram of the principle of rotation detection, is a perspective view of a main part of a conventional example of a detected object for a magnetic rotation sensor. 4.4'...Magnetic rotation sensor, 10.20...Detected object for magnetic rotation sensor, 12...
・Rotating shaft, 13a, 23a...teeth (unevenness), 22...
・Rotating tube.

Claims (3)

[Claims] (1) A detected object for a magnetic rotation sensor, characterized in that unevenness is directly formed on the outer circumferential surface of a rotating shaft of a magnetic material. (2) A detected object for a magnetic rotation sensor, characterized in that unevenness is directly formed on the inner circumferential surface of a rotating cylinder made of magnetic material. (3) The object to be detected for a magnetic rotation sensor according to claim 1 or 2, wherein the unevenness is directly formed on the end face of the object to be detected.