JPH05272617A - Resin toothed pulley - Google Patents

Abstract

PURPOSE:To prevent the lowering of magnetic sensor detection output caused when arrangement intervals among fellow magnets are narrow in a resin-made synchronous pulley, in which plural magnets are arranged, with the same surface polarities, on the same circumference. CONSTITUTION:Three of magnets 3, for detecting a rotation angle, are lined at regular intervals to be arranged on the same circumference of the web part 2 of a phenol-resin-made synchronous pulley 1. Also one magnet 3 is arranged in a position, parted about 180 deg. so as not to be effected by the magnetic field of the adjoining magnet. These magnets 3, every one is the same, are arranged with the S pole as the surface side. Steel material 4 is arranged among the magnets 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin toothed pulley having a rotation angle detecting function.

[0002]

2. Description of the Related Art A toothed pulley can transmit power without slipping in combination with a toothed belt and is used for driving a camshaft of a four-cycle internal combustion engine. Since the toothed pulley itself does not have the function of detecting the rotation angle, another device is added to the cam shaft or the like. When it is desired to reduce the size of the device, in the case of a resin toothed pulley, magnets or steel materials that are signal generating members at the same circumference or at arbitrary intervals on the same circumference for detecting the rotation angle are used for the web part or the flange part. If the pulley is a toothed pulley made of sinter, the rotation angle is measured by detecting the signal generating member with a sensor by arranging unevenness that is a signal generating member on the same part, and ignition of the internal combustion engine The timing and the fuel injection timing can be set.

[0003]

However, in the above-mentioned conventional resin toothed pulley in which a plurality of magnets are arranged as the signal generating member, a plurality of magnets are arranged on the same circumference with the same surface polarity. In this case, when the arrangement interval of the magnets is narrow, the output obtained from the magnetic sensor tends to decrease due to the influence of the magnetic field of the adjacent magnets. When such a tendency occurs, the waveform output obtained from the magnetic sensor is converted into the ON / OFF control waveform by the control circuit and output by the noise filter of the control circuit when the ignition timing and the fuel injection timing of the internal combustion engine are set. A low control waveform may be cut and a normal control waveform may not be obtained. The problem to be solved by the present invention is to detect a magnetic sensor that occurs when the arrangement interval of the magnets is narrow in a resin toothed pulley in which a plurality of magnets are arranged with the same polarity on the surface on the same circumference. This is to prevent a decrease in output and to obtain a normal control waveform without being cut by a noise filter when converting the output waveform obtained from the magnetic sensor into the control waveform by the control circuit.

[0004]

In order to solve the above-mentioned problems, a resin toothed pulley according to the present invention has a plurality of magnets on the same circumference of a web portion or a flange portion for detecting a rotation angle. In those arranged with the same polarity,
A steel material is arranged between the plurality of magnets. It is preferable that the plurality of magnets and the steel material are arranged so as not to project from the resin surface.

[0005]

The resin toothed pulley according to the present invention is used in combination with a magnetic sensor which is a means for detecting a rotation angle detecting signal. If the spacing between the magnets arranged on the same circumference of the resin toothed pulley is small, the output from the magnetic sensor will be affected by the magnetic field of the adjacent magnets. The output tends to be lower than the output obtained when the magnets are arranged at wide intervals that are not affected. But,
If the magnets are closely spaced and are affected by the magnetic fields of adjacent magnets, placing a steel material in the middle of the magnets prevents the output from the magnetic sensor from decreasing and is affected by the magnetic fields of adjacent magnets. It is possible to obtain the same value as the output waveform obtained when the magnets are arranged at wide intervals.

[0006]

EXAMPLES In carrying out the resin toothed pulley according to the present invention, the magnets are rare earth magnets, ferrite magnets, rubber magnets,
A plastic magnet or the like can be used. Figure 1
2 is a plan view of the resin toothed pulley, FIG. 2 is a side cross-sectional view of the resin toothed pulley, and FIG. 3 is an explanatory view of essential parts showing how a signal from a magnet is detected by a magnetic sensor.

Example On the same circumference of the web portion 2 of the phenol resin toothed pulley 1, three magnets 3 were arranged side by side at equal intervals for detecting the rotation angle (positions: A, B, C). Further, a position (position: 180 ° apart) that is not affected by the magnetic field of the adjacent magnet
One magnet 3 was arranged in D). Each of these magnets 3 has a diameter of 5 mm, a thickness of 5 mm, and a maximum energy product of 3.8 MG.
It was a ferrite magnet of Oe, and was arranged with the S pole on the surface side (towards the magnetic sensor). Between three magnets 3 arranged side by side (between positions A and B and between positions B and C)
The steel material 4 was arranged in. The phenol resin toothed pulley 1 was rotated, and the output from the magnet 3 was measured using a magnetic sensor 5 as shown in FIG. The output waveform obtained from the magnetic sensor 5 at this time is shown in FIG. Also, position A,
Table 1 shows the respective output values of B, C, and D.

Reference Example In the above embodiment, between positions A and B and positions B and C
In between, a second magnet having a N pole on the surface side was placed instead of the steel material. The second magnet, like magnet 3, has a diameter of 5 mm,
It is a ferrite magnet with a thickness of 5 mm and a maximum energy product of 3.8 MGOe. Similarly, the output waveform obtained from the magnetic sensor 5 is shown in FIG. Table 1 shows the output values at the positions A, B, C and D, respectively.

Conventional Example In the embodiment, the steel material 4 is not arranged. Similarly, the output waveform obtained from the magnetic sensor 5 is shown in FIG.
Table 1 shows the output values at the positions A, B, C and D, respectively.

[0010]

[Table 1]

In the above embodiment, if the magnet and the steel material are arranged so as not to project from the resin surface of the toothed pulley, the wind noise generated when the pulley is rotated is reduced, and the noise caused by the pulley rotation is suppressed. be able to.

[0012]

As is apparent from Table 1 and FIGS. 4 to 6, the resin toothed pulley according to the present invention has the same polarity on the front surface side of the magnets arranged on the same circumference as the signal generating member. When the placement interval is narrow and the magnetic field of adjacent magnets affects it, by placing a steel material between the magnets that are placed side by side, it is possible to prevent the output from the magnetic sensor from decreasing and to be affected by the magnetic field of adjacent magnets. With the same value as the output waveform obtained when the magnets are arranged at wide intervals, the output obtained from each magnet can be made substantially equal. Therefore, when the output waveform obtained from the magnetic sensor is converted into the control waveform by the control circuit, it is not cut by the noise filter and a normal control waveform can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a resin toothed pulley according to the present invention.

FIG. 2 is a side sectional view of FIG.

FIG. 3 is an explanatory view of relevant parts showing how a signal from a magnet of a resin toothed pulley is detected by a magnetic sensor.

FIG. 4 is an output waveform diagram detected by a magnetic sensor in the toothed pulley of the embodiment.

FIG. 5 is an output waveform diagram detected by a magnetic sensor in the toothed pulley of the reference example.

FIG. 6 is an output waveform diagram detected by a magnetic sensor in a conventional toothed pulley.

[Explanation of symbols]

 1 is a resin toothed pulley 2 is a web part 3 is a magnet 4 is a steel material 5 is a magnetic sensor

Claims (2)

[Claims] 1. A plurality of magnets are arranged on the same circumference of a web portion or a flange portion of a toothed pulley so as to detect a rotation angle with the same surface polarity, and a steel material is provided between the plurality of magnets. Resin toothed pulley characterized by being arranged. 2. The resin toothed pulley according to claim 1, wherein the plurality of magnets and the steel material are arranged so as not to project from the resin surface.