JPH01213517A - Rotation detector - Google Patents

Abstract

PURPOSE:To improve the resolution of the detected output of a rotation detector and, at the same time, to reduce the manufacturing cost of the detector by providing plural stages of magnetized zones on the outer peripheral surface of a cylindrical rotating body in such a way that the zones are arranged in the vertical direction and optional phase differences are set among them and sensor sections of a number corresponding to the zones in the vertical direction. CONSTITUTION:On the outer peripheral surface of a magnetic drum 2 which is a rotating body two pieces of N-S magnetized zones 4a and 4b are formed in such a way that the zones 4a and 4b are arranged in the vertical direction and respective intervals between the N and S poles of the zone 4a and those of the zone 4b are set at lambda/4. When the magnetic drum 2 rotates in the direction X, sensor sections 6a and 6b respectively detect the displacement of the magnetized zones 4a and 4b and output voltages e1 and e2 of the phase difference lambda/4 produced by the magneto- resistance effects of magneto-resistance effect elements R1 and R2 and R3 and R4 can be fetched from output terminals OUT1 and OUT2. When the phase difference between the magnetized zones 4a and 4b of the magnetized rum 1 is changed to lambda/8,... from the lambda/4, the phase difference of the output voltages e1 and e2 correspondingly become smaller. Therefore, the resolution can be improved sharply.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a rotation detection device, and more particularly, to a rotation detection device suitable for detecting rotational displacement of various motors such as a servo motor. Regarding.

(Prior Art) A conventional example of this type of rotation detection device will be described with reference to FIGS. 9 to 11. The rotation detection device 50 shown in FIG.
For example, a magnetic drum 52 is connected to a driving shaft 51 of a servo motor, and has a large number of N and S magnetized bands formed on its circular outer circumferential surface, and a magnetic sensor is disposed close to the circular outer circumferential surface of the magnetic drum 52. 53.

The magnetic sensor 53 is connected to the substrate 5 as shown in FIG.
4, two magnetoresistive elements Ra and Rb are arranged to match the spacing (phase) λ/2 between the north poles of the magnetized belt, and two magnetoresistive elements RC are arranged on the magnetoresistive element RC.

The magnetoresistive elements Ra and RC are arranged in a row so that Rd matches the spacing λ/2 between the S poles, and the magnetoresistive elements Ra and RC have a spacing λ/4. Then, a predetermined DC voltage V is applied between the power supply terminal B and the ground terminal 5 to drive the magnetoresistive elements Ra and Rb and to drive the magnetic drum 52 by the arrow X.
The displacement of each magnetic pole due to rotation in the direction is measured by the magnetoresistive element Ra.

Output voltages ea and eb shown in FIG. 12 based on changes in magnetoresistance of Rb and magnetoresistive element RC2Rd, respectively.
As a result of this change, it is taken out from the output terminal 0UT1゜0LJT2. Needless to say, the phase difference between the output voltages ea and eb is λ/4 due to the configuration of the magnetic sensor 53 described above.

Also, a device is known in which a bias magnet is added to the magnetic sensor 53 of the rotation detection device 50 described above to cause a phase change in the output voltages ea and eb.

By the way, in the rotation detecting device 50 having the above-described configuration, in order to improve the detection accuracy of the rotational displacement of the driving shaft 51, that is, the resolution, the magnetic pole spacing of the magnetized belt in the magnetic drum 52 is shortened, and the magnetic It is also necessary to reduce the distance between the magnetoresistive elements Ra to Rd of the sensor 53.

However, if the 'f11 pole spacing is simply shortened, the volume of the magnetic material of each magnetic pole will decrease, resulting in a problem that the S/N ratio of the output voltage of the magnetic sensor 53 will deteriorate.

Also, by using a stronger magnetic material while reducing the magnetic pole spacing! It is also possible to form an i-pole, but in this case there is a problem that the manufacturing cost of the magnetic drum increases.

Furthermore, there is a physical limit to reducing the distance between the magnetoresistive elements Ra7'Ill to Rd.

(Problems to be Solved by the Invention) As described above, conventional rotation detection devices have the problem of not being able to meet the demands for high performance from various aspects of manufacturing, cost, and characteristics.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rotation detection device that is easy to manufacture and can achieve high resolution while maintaining good output characteristics without causing a rise in manufacturing costs.

[Structure of the Invention] (Means for Solving the Problems) The rotation detection device of the present invention has a rotation detection device in which a plurality of stages of magnetized bands are vertically arranged on a circular outer peripheral surface and formed to have an arbitrary phase difference. The magnetic sensor includes a body and a magnetic sensor in which a number of sensor parts corresponding to the plurality of stages of magnetized belts are arranged vertically.

(for production) The operation of the rotation detection device having the above configuration will be explained below.

According to this device, a plurality of stages of magnetized bands are formed on the circular outer peripheral surface of a rotating body in a vertical arrangement and have an arbitrary phase difference, and a magnetic sensor has a number of magnetized bands corresponding to the magnetized bands. Since the sensor section is arranged vertically, high-resolution output characteristics can be obtained by setting the phase difference between the magnetized bands to a desired value without particularly shortening the magnetization interval. This makes it easy to manufacture, and also avoids a rise in manufacturing costs.

(Example) Examples of the present invention will be described in detail below.

The rotation detection device 1 shown in FIG. 1 includes a magnetic drum 2 as a rotating body whose center is connected to a driving shaft 51 similar to the conventional device, and a magnetic sensor 3 disposed near the outer periphery of the magnetic drum 2. It has

On the circular outer peripheral surface of the magnetic drum 2, as shown in FIG. 1 and enlarged FIG.
are arranged vertically, and the spacing (phase) between the north poles and between the south poles is λ/4.

As shown in the equivalent circuits of FIGS. 2 and 3, the magnetic sensor 3 includes a substrate 5 having the same vertical length as the magnetic drum 2, and is arranged perpendicularly to one surface of the substrate 5. Both the direct magnetic bands 71a are provided.

It has two sensor parts 5a and 5b corresponding to 4b.

One sensor section 6a includes a magnetoresistive element R1 formed in an upper region from the central portion of the ζ substrate 5, and a magnetoresistive element R2 formed in parallel to the magnetoresistive element R1. A power terminal B1 connected to the magnetoresistive element R1 via a wiring pattern, an output terminal 0LITt connected to the magnetoresistive element R2 via a wiring pattern, and both the magnetoresistive elements Rz, R2. A ground terminal E1 is commonly connected to the ground terminal E1 through a wiring pattern.

The other sensor section 6b is a magnetoresistive element R3 formed in a region below the center portion of the substrate 5.

Magnetoresistive element R4, power supply terminal Bt, output terminal 0U
T2 and a ground terminal E2.

According to this rotation detection device 1, the power terminal B1.

Between ground terminal E1 and power terminal B2. The magnetic drum 2 is connected with a predetermined DC voltage V applied between each ground terminal E2.
By rotationally driving the sensor part 6a in the direction of arrow X,
detects the displacement of the magnetized band 4a, and the sensor section 6a detects the displacement of the magnetized band 4b, and detects the phase difference λ/ based on the magnetoresistive effect of the magnetoresistive cables R1, R2 and the magnetoresistive elements R3, R4. 4 output voltage e1, e2 to output terminal 0UT1
.

It can be taken out from 0UT2.

In this case, the magnetized belt 4a of the magnetic drum 2.

4b phase difference from λ/4 to λ/8°λ/16・
By simply making the following changes, the phase difference between the output voltages e1ve2 can be correspondingly reduced, and thereby the resolution can be significantly improved.

In this case, each of the magnetized bands 4a, 4b! There is no need to particularly reduce the distance between the poles and the distance between the sensor sections 5a and 5b, and there is no need to make manufacturing difficult, increase manufacturing costs, or cause deterioration of the S/N ratio.

Next, other embodiments of the present invention will be described with reference to FIGS. 5 to 7.

In the rotation detecting device 1A shown in the figure, parts having the same functions as those shown in FIGS. 1 to 3 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

This rotation detection device 1A is different from the rotation detection device 1 described above in that the thickness of the magnetic drum 2A as a rotating body is made thicker than the magnetic drum 2, and a pair of N , S magnetic pole 7a.

7b is formed with a phase difference of, for example, λ/8 with respect to the N and SIa poles of the magnetized belt 4a, and instead of the magnetic sensor 3, the sensor portions 6a and 6b are provided on the thin magnetic drum 2A. This is because a magnetic sensor 3A is used which is provided with a rotational positioning sensor section 8 that also detects the displacement of the N and S magnetic poles 7a and 7b.

The rotational positioning sensor section 8 is the sensor section 6a.

It has the same configuration as 6b. That is, this rotary positioning sensor 4 no. 8 has magnetoresistive effect elements Rs, R6.
Power terminal E2. It has a ground terminal E3 and an output terminal 0UT3.

And power terminal B3. By rotating the magnetic drum 2A in the direction of the arrow X while applying a predetermined DC voltage V between the ground terminal E3, the output terminal 0UT is connected as described above.
The output voltages el and e2 are taken out from I and 0UT2, respectively, and the magnetoresistive element R is taken out from the output terminal 0UT3.
The output voltage e1 is based on the magnetoresistive effect of s and Re.
It is possible to extract an intermittent output voltage e3 with a phase difference of λ/8 and only one cycle.

This output voltage e3 can be used as a positioning signal for setting the rotational position of the magnetic drum 2A.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the invention.

For example, in the embodiment described above, the magnetic drum has two magnetized bands.
Although a case has been described in which the number of sensor sections of the magnetic sensor is two, the present invention is not limited to this, and it is also possible to use three or more sensor sections.

Furthermore, it goes without saying that the present invention can be applied even if the direction of rotation of the magnetic drum is opposite to that in the above-described embodiment.

[Effects of the Invention] According to the present invention described in detail above, by vertically arranging the configuration of the magnetic belt containing the rotating body and the magnetic sensor, it is possible to increase the resolution of the detection output, and it is also possible to improve the manufacturing efficiency. Therefore, it is possible to provide a rotation detection device that does not cause any problems in terms of cost and characteristics.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a device according to an embodiment of the present invention, Fig. 2 is a partially enlarged perspective view of the device, Fig. 3 is an equivalent circuit diagram of a magnetic sensor in the device, and Fig. 4 is a magnetic sensor in the device. FIG. 5 is a perspective view showing another example of the device according to the embodiment of the present invention, FIG. 6 is a partially enlarged perspective view of the device shown in FIG. The circuit diagram, Fig. 8 is a diagram of the output waveform of the magnetic sensor in the same device, Fig. 9 is a perspective view of the conventional device, Fig. 10 is an explanatory diagram showing the conventional device in an expanded state, and Fig. 11 is a diagram of the magnetic sensor in the conventional device. The equivalent circuit diagram of the sensor, FIG. 12, is an output waveform diagram of the same magnetic sensor. DESCRIPTION OF SYMBOLS 1... Rotation detection device, 2... Magnetic drum as a rotating body, 3... Magnetic sensors 2, 4a, 4b... Magnetized belt, 5a
, 5b...sensor section. Agent Patent attorney 3) T 1 Figure 1 Figure 2 Shio Figure 4 Figure 9 Figure 10

Claims (1)

[Claims] A rotating body having a plurality of stages of magnetized bands vertically arranged on a circular outer peripheral surface and having an arbitrary phase difference, and a number of sensor parts corresponding to the plurality of stages of magnetized bands arranged vertically. A rotation detection device comprising a magnetic sensor.