JP2606022Y2 - Electromagnetic rotation sensor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic rotation sensor used for, for example, a crank angle sensor for detecting the rotation speed of an automobile engine, and more particularly to a technique for stabilizing an output waveform of the sensor.

[0002]

2. Description of the Related Art For example, in an engine equipped with an electronically controlled fuel injection device, in order to control the fuel injection amount, ignition timing, and the like, the rotation angle of a camshaft or a crankshaft is detected to reduce the engine speed. A rotation sensor for detecting is provided. This rotation sensor is a so-called electromagnetic type rotation sensor.
A rotation sensor is known (Japanese Utility Model Application Laid-Open No. 63-183375).
Gazette). Such an electromagnetic rotation sensor is, for example, shown in FIG.
As shown in FIG. 1, a rotor 1 that rotates in synchronization with a camshaft or a crankshaft as a rotating portion,
A portion to be detected provided in
An electromagnetic pickup 3 for detecting the detected part ;
Consists of In this case, the detected part is the rotor 1
A plurality of outer circumferential surfaces are provided at a predetermined pitch along the rotation direction.
The projection 2 is made of a magnetic material.
The rotation angle of the camshaft or the crankshaft is detected based on the back electromotive force generated in the electromagnetic pickup 3 due to a change in the amount of magnetic flux when passing through the vicinity of the electromagnetic pickup 3 .

[0003]

However, in such a conventional electromagnetic rotation sensor, the rotor 1 has a motor.
Rotate synchronously with the shaft or crankshaft
When installed close to a gear-shaped rotating magnetic body
Has the following problems. For example, in a crank angle sensor for detecting the number of revolutions of an automobile engine, as shown in FIG. 4, the rotor 1 is fixedly mounted on a side surface of a ring gear 4 (a gear-shaped rotating magnetic body) mounted on a crankshaft. I am trying to do it.

[0004] As described above, the rotor 1 approaches the ring gear 4 .
If to provided, rotating magnetic der electromagnetic pickup 3 in addition to the magnetic flux change due to the protruding portion 2 of the rotor 1
The change in the amount of magnetic flux due to the teeth 4a of the ring gear 4 is picked up as noise. That is, a change in the amount of magnetic flux due to the teeth 4a of the ring gear 4 is superimposed as noise on the normal output signal, and the output waveform of the sensor is disturbed (see FIG. 2 ).

[0005] In view of the above-mentioned problems in the prior art, the present invention provides a rotor that rotates in synchronization with a rotating part.
Close to a gear-shaped rotating magnetic body that rotates in synchronization with
In such an electromagnetic rotation sensor, the electromagnetic pickup is driven by a protrusion of a magnetic material which is a detected part of the rotor .
Another object of the present invention is to prevent a change in the amount of magnetic flux due to the teeth of the rotating magnetic material from being picked up as noise in addition to the change in the amount of magnetic flux, thereby stabilizing the output waveform of the sensor.

[0006]

[Means for Solving the Problems] For this reason, the present invention is, times
A rotating part, a rotor rotating in synchronization with the rotating part, and a rotor
A portion to be detected provided in
Is an electromagnetic pickup which detects the detected portion, the
The detected part is provided on the outer peripheral surface of the rotor.
Is a magnetic body provided at a predetermined pitch along the rotation direction
And the rotor is the same as the rotating part.
Provided in close proximity to a gear-shaped rotating magnetic body
An electromagnetic rotation sensor comprising:
Of the rotating magnetic body and the teeth of the rotating magnetic body
The position and the pitch match each other .

[0007]

In this configuration, the protrusion on the outer peripheral surface of the rotor is
And a tooth portion of the rotating magnetic outer peripheral surface, times the rotational position and pitch respectively results so as to match, in addition to electromagnetic pickup amount of magnetic flux change due to the protrusion of the rotor outer circumferential surface
The change in the amount of magnetic flux due to the teeth of the diamagnetic member will not be picked up as noise, that is, the change in the amount of magnetic flux due to the teeth of the rotating magnetic body will not be superposed as noise on the normal output signal.

As a result, the output waveform of the sensor is not disturbed, the output waveform can be stabilized, and the regular output by the rotor is increased, so that the detection accuracy of the sensor can be improved. it can.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings. In FIG. 1, a crank angle sensor as an electromagnetic rotation sensor includes a rotor 1 that rotates in synchronization with a crankshaft as a rotating unit, and a test object provided on the rotor 1.
A protruding portion and the detected portion provided in proximity to the detected portion.
And an electromagnetic pickup 3 for detecting the
The detection section is provided on the outer peripheral surface of the rotor 1 along a predetermined
As in the prior art , a plurality of protrusions 2 made of a magnetic material are provided .

A ring gear 4 is mounted on the crankshaft as a gear-shaped rotating magnetic body which rotates in synchronization with the crankshaft. The rotor 1 is fixedly mounted on a side surface of the ring gear 4. Have been. That is, the rotor 1
The ring gear 4 to rotate in synchronism with the crankshaft
It is arranged close . Here, the protruding portion 2 on the outer peripheral surface of the rotor 1 and the tooth portion 4a on the outer peripheral surface of the ring gear 4 are made to have the same rotational position and pitch.

According to such a configuration, the rotational position and the pitch of the protruding portion 2 on the outer peripheral surface of the rotor 1 and the tooth portion 4a on the outer peripheral surface of the ring gear 4 are made to match each other. In addition to the change in the amount of magnetic flux caused by the protrusion 2 of the rotor 1, the change in the amount of magnetic flux caused by the teeth 4a of the ring gear 4, which is a rotating magnetic body, is not picked up as noise.
That is, a change in the amount of magnetic flux due to the teeth 4a of the ring gear 4 does not become noise and is superimposed on the normal output signal.

2 and 3 show the relationship between the projection 2 of the rotor 1 and the tooth 4a of the ring gear 4 and the relationship between these and the output waveform of the sensor in the conventional and the present invention, respectively. According to these figures, the position and pitch of the projection 2 of the rotor 1 and the teeth 4a of the ring gear 4 in the rotation direction are different in the related art, so that the output by the rotor 1 is different from the output by the rotor 1 shown by the solid line. And the composite output of the output by the ring gear 4 shown by the one-dot chain line is shifted as shown by the dotted line, and the change in the amount of magnetic flux by the ring gear 4 is superimposed as noise on the normal output signal. Since the positions and pitches of the projections 2 and the teeth 4a of the ring gear 4 in the rotational direction match, the output of the rotor 1 matches the combined output of the output of the ring gear 4 with the output of the rotor 1, and the ring gear 4 The change in the magnetic flux amount due to No. 4 becomes noise with respect to the normal output signal and does not overlap.

As a result, the output waveform of the sensor is not disturbed, the output waveform can be stabilized, and the regular output from the rotor 1 is increased, thereby improving the detection accuracy of the sensor. Can be. In the above embodiment, a crank angle sensor is described as an electromagnetic rotation sensor, and the rotor 1 is synchronized with the crankshaft.
Gear 4 as a gear-shaped rotating magnetic body that rotates
Has been described, but the present invention is not limited to this. In short, it rotates in synchronization with the rotating unit.
The rotor rotates in synchronization with the rotating part.
The present invention can be applied to any electromagnetic rotation sensor that is disposed close to a body .

As described above, the present invention has been described with reference to the specific embodiment. However, the present invention is not limited to this, and is attached to the present invention by a person skilled in the art. It should be noted that various changes and modifications can be made without departing from the scope of the utility model registration claims.

[0015]

As described above, according to the electromagnetic rotation sensor of the present invention, the rotor that rotates in synchronization with the rotating part
Into a gear-shaped rotating magnetic body that rotates in synchronization with the rotating part
In an electromagnetic rotation sensor disposed close to a magnetic sensor, a protrusion of a magnetic material forming a detected portion on an outer peripheral surface of a rotor and a rotating magnetic field are provided.
Since the rotational position and pitch of the teeth on the outer peripheral surface of the body are matched with each other, the electromagnetic pickup
In addition to the change in magnetic flux due to the protrusion, the change in magnetic flux due to the teeth of the rotating magnetic material can be prevented from being picked up as noise, and the output waveform of the sensor can be stabilized and the sensor detection accuracy can be improved by increasing the normal output. This is a practical effect that can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an electromagnetic rotation sensor according to the present invention, wherein FIG. 1A is a front view, and FIG.

FIG. 2 is a diagram showing a relationship between a projection of a conventional rotor and a tooth of a ring gear, and a relationship between these and output waveforms of a sensor.

FIG. 3 is a diagram showing the relationship between the protrusion of the rotor and the tooth of the ring gear of the present invention and the relationship between these and the output waveform of the sensor.

FIG. 4 is a side view showing an example of a conventional electromagnetic rotation sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor 2 Projection part 3 Electromagnetic pickup 4 Ring gear 4a Tooth part

Claims (1)

(57) [Scope of request for utility model registration] A rotating part, a rotor rotating in synchronization with the rotating part, a detected part provided on the rotor,
An electromagnetic pickup that is provided in proximity to and detects the detected part, and the detected part is arranged on the outer peripheral surface of the rotor along a rotational direction.
From a plurality of protrusions made of magnetic material provided at a predetermined pitch
The rotor is formed in a gear shape and rotates in synchronization with a rotating part.
An electromagnetic rotation sensor that is provided close to the diamagnetic material
There, the teeth portion of the rotating magnetic outer peripheral surface and the projection of the rotor outer circumferential surface
Is an electromagnetic rotation sensor whose rotation direction position and pitch match each other .