JPS6197517A - Magnetic type encoder - Google Patents

Abstract

PURPOSE:To achieve a lower cost and a less space with an easy adjustment, by magnetizing a magnetic drum in two tracks while magnetoresistance MR elements for outputs A and B and an element for IX output (one pulse per rotation) are provided integral on a (MR) element block. CONSTITUTION:This encoder is made up of a motor 1, an output shaft 2, a magnetic drum 3 and an MR element block 4. A drum 3 is magnetized in a multipole on the circumference thereof for outputs A and B in one pulse per rotation for output IX. The resulting magnetic fields are detected with MR elements 4a and 4b evaporated on the MR element block 4. An MR element 4a for detecting outputs A and B and an MR element 4b for detecting the output IX are integrated on the block 4 of the output shaft 2 and can detect the outputs A, B and IX by positional adjustment of one MR element block. On the other hand, a clearance T is provided between the individual magnetizations to keep the outputs from interfering with one another while the MR elements have a clearance T+alpha therebetween.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a magnetic encoder for detecting the position, speed, etc. of a small electric motor, which is widely used in the audio field, video field, industrial field, etc. .

BACKGROUND OF THE INVENTION In recent years, encoders for small electric motors have been changing from optical to magnetic encoders, and among magnetic encoders, the type using Hall elements and magnetoresistive elements (hereinafter referred to as MR elements), as shown in Figure 6, is becoming more popular. Common. The configuration will be explained below using FIG. 6. In the figure, 1 is a motor. Reference numeral 2 denotes a magnetic drum fixed to the output shaft of the motor 1, 3 output shafts 2, whose outer periphery is multipole magnetized, and an MR element block 4 detects the magnetic field. Note that for output of one pulse per revolution (hereinafter referred to as IX output), the magnetic field of the magnet 5 for IX output is detected by the Hall element 6.

In addition to the above-mentioned conventional configuration, as shown in the third figure, two tracks of magnetization are performed on the outer circumference of the magnetic drum 3, and the MR element block 4 is
A method of configuring by using a and 4b has also been considered.

The operation of the magnetic encoder configured as described above (1°η) will be explained below.

When the motor 1 is powered, the output shaft 2 rotates, and the magnetic drum 3 rotates accordingly. The magnetic drum 3 is magnetized on its outer periphery or on its plane, and changes in the magnetic field occur in synchronization with rotation. This change is reflected in the MR element block 4 and the Hall element 6.
is detected and converted to voltage. This output is amplified and the rotational speed of the motor is increased.

Detects two positions in the rotation direction.

The output of outer periphery magnetization is from MR element block 4 in Figures 3 and 6.
, 4a, and the outputs are the human output and B output shown in FIG.

The IX output is detected by the MR element block 4b in FIG. 3, and by the Hall element 6 in FIG. The output is the IX output shown in FIG.

The MR element is made by depositing a magnetic metal film on a special glass substrate.
This is a national electricity conversion element with a pattern formed using a photo-etching process, and is a sensor that utilizes the characteristic that the resistance value changes when a magnetic field is applied. Moreover, it has the advantage of being able to extract a signal with a frequency twice that of magnetization.

Problems to be Solved by the Invention However, in the configuration shown in FIG.
Two element blocks 4a and 4b are required, which poses problems in terms of cost and space.
It is also necessary to perform position adjustment with the element blocks 4a and 4b twice. For example, if the outer diameter of the magnetic drum 3 is 20 mm, the A phase,
If the B-phase output requires 4Q○ pulses for one rotation, it will be about 80 pm during magnetization, and considering the output, the clearance between the magnetic drum 3 and the MR element blocks 4a and 4b is 0.1
It is very difficult to adjust as it needs to be below the throat. Furthermore, in the configuration shown in FIG. 6, it is very difficult to adjust the position of the IX output magnet 6 in order to synchronize the human output or B output with the IX output.

As mentioned above, the conventional configuration has problems in terms of work, cost, and space. .

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a magnetic encoder that allows easy position adjustment of an MR element block, is low in cost, and has a small space.

Means for Solving the Problems In order to solve the above problems, the magnetic encoder of the present invention includes an MR element for human output and B output in the MR element block,
The MR element for IX output is simultaneously deposited and integrated, and the direction of the evaporation position of the MR element is changed by 900° to prevent interference between multipolar magnetization and IX magnetization.

The present defense is based on the above-described configuration, so that the MR element block has A
By integrating the MR element for , B output, and the MR element for ACT Adjustment, synchronization, etc. are simple because they are based only on the magnetization error of the magnet. Moreover, the MR element's deposition position is arranged with its direction changed by 90' so that it is less affected by the respective magnetization (AtB output and IX output), and the magnetic drum is magnetized accordingly. A, B
Interference between output and IX output is also eliminated.

Example Below, regarding a magnetic encoder according to an example of the present invention,
This will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.

In the figure, 1 is a motor. 2 is the output shaft of the motor 1. 31"j: A magnetic drum fixed to the output shaft 2. This magnetic drum 3 has a human output on the outer periphery, a multi-pole magnetization for the output B, and a magnetic drum for the output. Magnetization is performed with one pulse per rotation.

This magnetic field is detected by MR elements 4a and 4b deposited on two MR element blocks 4. 2 MR element block 4
The MR element 4a for detecting human output and B output and the MR element 4b for detecting mechanical x output are integrated into one MR element.
By adjusting the position of the element block, human output, B output, and IX output can be detected. A clearance T is provided between each magnetization so that the multi-pole magnetization for human output and B output and the magnetization for IX output do not interfere with each other, and a clearance T+α is provided between each of the MR elements. During magnetization 8
In the case of 0 μm, it is appropriate that T is 0.5M or more and T+α is 1 or more.

Since the MR element has the characteristic of generating two outputs by a pair of N-3 magnetic fields, the MR element 4b for IX blade is placed in the evaporation direction that is 90 degrees different from the evaporation direction of the MR element 4a for human output and B output.
Deposit f and make one output. Therefore, the influence of multi-pole magnetization is less likely to affect the MR element 5 for IX output.

Effects of the Invention As described above, according to the present invention, the magnetic drum is subjected to two-track e&, and the MR element block is integrated with the MR element for A output, the B output, and the MR element for IX output. This makes it easier to operate, lowers costs, and allows for smaller space.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a magnetic encoder of the present invention, FIG. 2 is a configuration diagram of a magnetoresistive MR element block used in the same magnetic encoder, and FIG. 3 is a configuration diagram of a conventional magnetic encoder.
4 and 6 are explanatory diagrams of a magnetoresistive element block used in the same encoder, FIG. 6 is a configuration diagram of another conventional magnetic encoder, and FIG. 7 is a waveform diagram of the encoder output. 3...Magnetic drum, 4...Magnetic resistance M
R element block, 4a... Magnetoresistive element for A, B output, 4b... Magnetoresistive element for IX output. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] It is equipped with a magnetic drum whose outer periphery is multi-pole magnetized and magnetized for one pulse per rotation, and one magnetoresistive element block for detecting the magnetic field, and the magnetoresistive element block has the multi-pole magnetization. A magnetic encoder comprising a magnetoresistive element for detecting magnetization and a magnetoresistive element for detecting one pulse of magnetization per rotation, and in which both magnetoresistive elements are arranged at right angles. .