JP2871380B2 - Toothed pulley - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A toothed pulley can transmit power without slippage 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 a function of detecting the rotation angle, it is necessary to add another device to the camshaft or the like. If the toothed pulley is made of non-magnetic material such as resin or aluminum die-cast, the boss, rib, or rim part is used to detect the rotation angle. You may make it arrange | position the block of the magnet or a steel material which is a generating member. Further, if the toothed pulley is made of a sintered material, which is a magnetic material, the same portion may be provided with unevenness, which is a signal generating member. The rotation angle is measured by detecting these signal generating members with a magnetic sensor such as an electromagnetic pickup sensor, and the ignition timing and fuel injection timing of the internal combustion engine are determined.

[0003]

However, in the conventional toothed pulley made of non-magnetic material in which a plurality of magnets are arranged as a signal generating member, a plurality of magnets are provided on the same circumference with the same surface polarity. When the distance between the magnets to be arranged is narrow, the output obtained from the electromagnetic pickup sensor, which is the magnetic sensor,
The output from the second magnet adjacent to the first magnet, which is subsequently detected, tends to be lower than the output from the first magnet. This is because the second magnet is affected by the magnetic field of the first magnet. When such a tendency occurs, the output waveform obtained from the magnetic sensor is converted into an ON / OFF control waveform by the control circuit, and the output is output by the noise filter of the control circuit when the ignition timing and the fuel injection timing of the internal combustion engine are determined. Waveform may be cut and a normal control waveform may not be obtained. There is also a technique of disposing a steel block as a signal generating member on the same circumference of the boss or rib or rim of a toothed pulley made of non-magnetic material,
The output obtained from the magnetic sensor when the steel material block is arranged as the signal generating member is lower than the output obtained when the magnet is arranged. The problem to be solved by the present invention is to provide a toothed pulley made of a non-magnetic material in which a plurality of magnets are arranged on the same circumference with the same polarity on the same circumference for rotation angle detection. To prevent a decrease in the magnetic sensor detection output that occurs when the area is narrow, and to obtain a normal control waveform without being cut by a noise filter when the output waveform obtained from the magnetic sensor is converted into a control waveform by the control circuit. It is to be.

[0004]

In order to solve the above-mentioned problems, a plurality of toothed pulleys made of a non-magnetic material according to the present invention are provided on the same circumference of a boss, a rib or a rim for detecting a rotation angle. Are arranged with the same polarity on the surface, and a first magnet detected earlier by a sensor during rotation of the toothed pulley, and a second magnet adjacent to the first magnet.
Wherein the second magnet is in a positional relationship affected by the magnetic field of the first magnet, the second magnet has a stronger magnetic force than the first magnet, and has a surface facing the sensor.
The outer diameter is smaller than that of the first magnet.

[0005]

The toothed pulley according to the present invention is used in combination with a magnetic sensor such as an electromagnetic pickup sensor which is a means for detecting a rotation angle detection signal. When the first magnet passes through the magnetic sensor, the magnetic sensor detects the change in the magnetic flux, and there is no magnet that affects the change before the first magnet. The magnetic force of the first magnet is directly detected. However, there is a first magnet which affects this before the second magnet. When the magnetic sensor detects the magnetic force of the second magnet, it is affected by the magnetic field of the first magnet. Therefore, the magnetic sensor detects the magnetic force obtained by subtracting the influence of the magnetic field of the first magnet from the magnetic force of the second magnet. Will be detected. Therefore, in order to make the output obtained when the second magnet passes through the magnetic sensor substantially equal to or more than the output obtained when the first magnet passes through the magnetic sensor,
The magnetic force of the second magnet is made stronger than the magnetic force of the first magnet. For the second magnet, merely increasing the magnetic force is not enough. If the outer diameter of the surface facing the magnetic sensor is the same or larger than that of the first magnet, then the influence of the magnetic field of the second magnet However, since the magnetic force of the first magnet extends to a portion before the magnetic sensor detects the magnetic force, the outer diameter of the second magnet is made smaller than that of the first magnet in consideration of preventing such a state. There is a need. With the toothed pulley according to the present invention having the above-described configuration, the output obtained when the second magnet passes through the magnetic sensor is output when the first magnet passes through the magnetic sensor immediately before. Is almost equal to or higher than the output obtained in step (1).

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In implementing a toothed pulley according to the present invention,
As the magnet, a rare earth magnet, a ferrite magnet, a rubber magnet, a plastic magnet, or the like can be used. Figures 1-3
1 shows an embodiment of a toothed pulley to which the present invention is applied.
FIG. 1 is a plan view of a resin-made toothed pulley, FIG. 2 is a side sectional view of the resin-made toothed pulley, and FIG. 3 is a diagram showing how a magnetic sensor detects a signal from a magnet which is a signal generating member. FIG. In the rib of the toothed pulley 1, a plurality of magnets are embedded on the same circumference with the same surface as the rib surface and the same polarity on the surface. As shown in FIG. 3, during rotation of the toothed pulley, a change in magnetic flux is detected by the magnetic sensor 2 installed so as to face the surface of the magnet. , First
A second magnet 12 adjacent to the second magnet is disposed,
Is in a positional relationship affected by the magnetic field of the first magnet as it is. There is no magnet that affects this before the first magnet 11, and in addition, a third magnet 13 and a fourth magnet 14 are arranged on the same circumference. An example of the toothed pulley 1 having such a magnet arrangement will be described in detail below with reference to a conventional example and a comparative example.

(Embodiment) As the first magnet 11 and the fourth magnet 14, ferrite magnets (diameter: 5 mm, thickness: 5 m)
m, the maximum energy product of 4.5 MGOe) was arranged such that the south pole was opposed to the magnetic sensor 2. Further, as the second magnet 12 and the third magnet 13, a rare earth magnet (diameter 4 mm, thickness 3 mm, maximum energy product 22MGOe) is used.
The S pole was arranged so as to face the magnetic sensor 2. Using an electromagnetic pickup sensor as the magnetic sensor 2, as shown in FIG. 3, it is installed at a position where the center of each magnet is traced, the toothed pulley 1 is rotated at 25 rpm, and the output obtained from the magnetic sensor 2 is measured. did. FIG. 4 shows an output waveform obtained from the magnetic sensor 2 and a control waveform generated based on the output waveform. In addition, each output of the peaks J, K, L, and M of the output waveform (corresponding to the positions of the first magnet 11, the second magnet 12, the third magnet 13, and the fourth magnet 14, respectively). The values are shown in Table 1.

(Conventional Example) First Magnet 11, Second Magnet 1
2. As the third magnet 13 and the fourth magnet 14, ferrite magnets (diameter 5 mm, thickness 5 mm, maximum energy product 4.5 MGOe) were arranged such that the S pole was opposed to the magnetic sensor 2. Using an electromagnetic pickup sensor as the magnetic sensor 2, as shown in FIG. 3, it is installed at a position where the center of each magnet is traced, and the toothed pulley 1 is rotated at 25 rpm.
And the output obtained from the magnetic sensor 2 was measured. FIG. 5 shows an output waveform obtained from the magnetic sensor 2 and a control waveform generated based on the output waveform. Table 1 shows the output values of the peaks J, K, L, and M of the output waveform.
Shown in

Comparative Example A ferrite magnet (diameter 5 mm, thickness 5 m) was used as the first magnet 11 and the fourth magnet 14.
m, the maximum energy product of 4.5 MGOe) was arranged such that the south pole was opposed to the magnetic sensor 2. Further, as the second magnet 12 and the third magnet 13, a rare earth magnet (diameter 5 mm, thickness 5 mm, maximum energy product 22MGOe) is used.
The S pole was arranged so as to face the magnetic sensor 2. Using an electromagnetic pickup sensor as the magnetic sensor 2, as shown in FIG. 3, it is installed at a position where the center of each magnet is traced, the toothed pulley 1 is rotated at 25 rpm, and the output obtained from the magnetic sensor 2 is measured. did. FIG. 6 shows an output waveform obtained from the magnetic sensor 2 and a control waveform generated based on the output waveform. Table 1 shows the output values of the peaks J, K, L, and M of the output waveform.

Reference Example In the first embodiment, instead of the first magnet 11, the second magnet 12, the third magnet 13, and the fourth magnet 14, a steel block (diameter of 5 mm) is provided at a position where these are arranged. , Thickness 5mm, rolled steel for general structure JIS
G 3101). An electromagnetic pickup sensor is used as the magnetic sensor 2, and as shown in FIG. 3, it is installed at a position where the center of each steel material block is traced, and the toothed pulley 1 is rotated at 25 rpm, and the output obtained from the magnetic sensor 2 is obtained. It was measured. FIG. 7 shows an output waveform obtained from the magnetic sensor 2 and a control waveform generated based on the output waveform. Table 1 shows the output values of the peaks J, K, L, and M of the output waveform.

FIG. 4 shows that in the toothed pulley according to the embodiment of the present invention, the detection output of the second magnet by the magnetic sensor is equal to or greater than the detection output of the first magnet, and the output waveform is controlled by the control circuit. A normal control waveform can be obtained without being cut by a noise filter when converting into a waveform.
The detection outputs (L, L) of the third magnet 13 and the fourth magnet 14 are provided.
M) is also large, but there is no magnet adjacent to the positional relationship affecting the magnetic field of these magnets. In the conventional example, the detection output (K, L) of the second magnet and the third magnet is small, and when the output waveform obtained from the magnetic sensor is converted into the control waveform by the control circuit, The detection output of the third magnet is cut by the noise filter, and an accurate control waveform cannot be obtained. In the comparative example, the second magnet affects the magnetic field of the first magnet, and the detection output (J) of the first magnet is small. As a result, when the output waveform obtained from the magnetic sensor is converted into the control waveform by the control circuit, the detection output of the first magnet is cut by the noise filter, and an accurate control waveform cannot be obtained. In the reference example, since all the detection outputs are small and are cut by the noise filter, a control waveform cannot be obtained.

[0012]

[Table 1]

[0013]

As described above, the toothed pulley according to the present invention has the first and second adjacent magnets arranged for detecting the rotation angle, and the first and second magnets are arranged with respect to the second magnet. Even when the magnetic field of the magnet has an effect, the detection output of the second magnet by the magnetic sensor can be made equal to or more than the detection output of the first magnet. As a result, when the output waveform obtained from the magnetic sensor is converted into the control waveform by the control circuit, there is no output waveform cut by the noise filter, and a normal control waveform can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a side sectional view of FIG.

FIG. 3 is an explanatory view of a main part showing how a signal from a magnet of a 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 and a control waveform diagram obtained from the output waveform.

FIG. 5 is an output waveform diagram detected by a magnetic sensor in a conventional toothed pulley and a control waveform diagram obtained from the output waveform.

FIG. 6 is an output waveform diagram detected by a magnetic sensor in a toothed pulley of a comparative example and a control waveform diagram obtained from the output waveform.

FIG. 7 is an output waveform diagram detected by a magnetic sensor in the toothed pulley of the reference example and a control waveform diagram obtained from the output waveform.

[Explanation of symbols]

 1, a toothed pulley 2, a magnetic sensor 11, a first magnet 12, a second magnet 13, a third magnet 14, a fourth magnet

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-208570 (JP, A) JP-A-5-272617 (JP, A) Japanese Utility Model Application No. 57-12861 (JP, U) Japanese Utility Model Application No. Sho 61- 188308 (JP, U) Japanese Utility Model Showa 61-20 (JP, U) Japanese Utility Model Application Hei 6-69336 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 55/48 G01B 7 / 30 G01D 5/245

Claims (1)

(57) [Claims] 1. A plurality of magnets having the same surface polarity for rotation angle detection are arranged on the same circumference of a boss, rib, or rim of a toothed pulley made of a non-magnetic material. A first magnet, which is detected earlier by a sensor during rotation of the toothed pulley, and a second magnet adjacent to the first magnet, wherein the second magnet is affected by the magnetic field of the first magnet In a positional relationship, the second magnet is
A toothed pulley, wherein the magnetic force is stronger than the first magnet, and the outer diameter of a surface facing the sensor is smaller than the first magnet.