JPH05332763A - Portable measurement device for armature brush size - Google Patents

Abstract

PURPOSE:To enable a dimensional check to be efficiently and accurately made by causing the displacement of a movable section in contact with an armature brush to be outputted as an electrical signal. CONSTITUTION:This dimensional inspection device 1 has a handle 40 and a movable section A is slidably fitted to the handle 40. On the other hand, a stationary section B is fixed to one end of the handle 40. A terminal record device 10 is electrically connected to an arithmetic processing section 6, and temporarily stores a measurement value. For measuring the dimension of an armature brush 8, the handle 40 is held and the stationary section B is kept in contact with the external surface of a commutator 9, thereby determining the reference of measuring length. Then, the movable claw 3 of the movable section A is caused to come in contact with the upper end of the brush 8. In this state, a distance between the lower end of the section B and the claw 3 is measured, thereby measuring the dimension of the brush 8. This measurement value is saved in the device 10. Also, the saved measurement value is transferred to a computer for the maintenance and management of the dimension of the brush 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an electric motor,
The present invention relates to armature brush size measurement for maintaining and managing the size of an armature brush in a pre-specified optimum state.

[0002]

2. Description of the Related Art In general, various electric motors are used in railway vehicles and other various drive devices. A DC motor is one of the electric motors. For example, in a railcar, this DC motor takes in a DC current from a pantograph, which is a current supply source, and uses that current as a drive current.

FIG. 6 is a sectional view of a conventional DC motor.
The DC motor is composed of a rotor 30 and a stator 31, and the rotor 30 is composed of an armature 32, a commutator 34, a shaft 36, and a cooling fan, while the stator 31 is a yoke 33,
It is composed of a field magnet 35, an armature brush 37, and a bearing portion. A magnetic field is generated in the field 35 on the side of the stator 31, while a conductor is wound around the armature 32, and the position at which current flows is changed momentarily via the commutator 34 to generate a magnetic field on the side of the rotor 30. The rotor 30 is rotated by the interaction of the magnetic fields.

In the DC motor, the DC current is supplied to the armature 32 through the contact between the armature brush 37 and the commutator 34. The armature brush 37 is provided in radial contact with the cylindrical commutator 34 fixed to the shaft 36. Since the commutator 34 rotates while contacting the armature brush 37, the armature brush 3
7 wears as it rotates. Therefore, conventionally, the amount of wear of the armature brush 37 is inspected to perform maintenance including maintenance such as replacement. In the dimensional inspection of the conventional armature brush 37, an inspector uses a mechanical caliper to measure the armature brush 3.
A method using a limit gauge for pressing against No. 7 and measuring a difference from a predetermined reference dimension is implemented.

[0005]

However, there are the following problems in the dimension inspection of the above-mentioned conventional armature brush. (1) For the dimension inspection of the armature brush with the conventional calipers,
Since the measurer inserts calipers into the motor in an unreasonable manner and records the dimensions of the read armature brush, it takes a long time to measure one location. Therefore, it takes a huge amount of time and labor to inspect all the armature brushes, resulting in poor work efficiency. (2) In the dimension inspection of the armature brush using a conventional caliper, the measurement person visually reads the dimension of the armature brush, and thus the measurement value includes a reading error. (3) In addition, there is a large variation in measurement accuracy due to individual differences among measurers. (4) Furthermore, when the measurer writes the measured value in the ledger, there is a possibility that the measured value may be entered incorrectly. (5) Further, when the measurement result is input to the management computer, the measurer manually transfers the measurement result from the ledger to the reading sheet. The transfer work takes time,
The armature brush data processing requires a great amount of work time, and the processing itself is complicated.

The present invention solves the problems of the above-described conventional dimensional inspection of armature brushes, efficiently and accurately conducts dimensional inspection of armature brushes, and a computer for processing measured data after completion of inspection. It is an object of the present invention to provide an armature brush dimension inspection device that facilitates input to the armature brush and efficiently manages the history of the armature brush.

[0007]

In order to achieve the above object, the present invention provides a portable armature brush size measuring device for measuring the size of an armature brush mounted on a commutator rotating in a DC motor. A fixed part that contacts the commutator and a movable part that is relatively displaceable with respect to the fixed part and that contacts the armature brush, and a displacement amount of the movable part are converted into an electric signal to convert the armature brush. It comprises an arithmetic processing means for measuring dimensions and further has a storage means for storing the output of the arithmetic processing means.

[0008]

According to the present invention, the portable armature brush size measuring device is brought into contact with the commutator as described above, and the armature brush is movable relative to the fixed portion. Since it is composed of a movable part and outputs the displacement amount of the movable part as an electric signal, the dimensional inspection of the armature brush can be carried out efficiently and accurately, and the input of the measured data to the processing computer after the inspection is completed. Can be easy,
The history of the armature brush can be efficiently managed.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. The structure of the armature brush size inspection device of the present invention will be described below. FIG. 1 is a block diagram of a dimension inspection device for an armature brush of the present invention. In the figure, an armature brush dimension inspection device 1 of the present invention includes a movable part A, a fixed part B, and an arithmetic processing part 6, and further has a terminal recording device 10.

The movable part A has a movable claw 3 that comes into contact with the upper end of the armature brush 8 of the electric motor, while the fixed part B is on the side of the commutator 9 of the electric motor and the armature brush 8. It has a fixed claw 2 that contacts. In addition, the arithmetic processing unit 6
Is a sensor unit 4 for measuring the movement amount of the movable claw 3 of the movable unit A, an A / D conversion unit 7 for converting an analog measurement value of the sensor unit 4 into a digital amount, a display unit 5 for displaying the measurement value, etc. have.

The armature brush dimensional inspection device 1 of the present invention has a handle 40. The movable part A is slidably attached to the handle 40, while the fixed part B is an end of the handle 40. It is fixed to the section. The terminal recording device 10 is electrically connected to the arithmetic processing unit 6 and temporarily stores the measurement value of the arithmetic processing unit 6.

FIG. 2 is a block diagram of the terminal recording device of the present invention. In the figure, a terminal recording device 10 has a storage unit 12 for storing measured values, a data display unit 11 for displaying the measured values, and various switches 13, and is further connected to a management computer 15 via a communication line 14 or the like. Has been done.
The storage of the measured values in the storage unit 12 is performed by operating the switch 13 of the terminal recording device 10, for example. Instead of the switch 13 of the terminal recording device 10,
It can also be performed by operating a switch installed at a location on the armature brush dimension inspection device 1 side.

The measurement value can be confirmed by the display unit 5 installed in the armature brush size inspection device 1 or the data display unit 11 of the terminal recording device 10.
Therefore, the measurer must display the display unit 5 or the data display unit 1
After confirming the measured value in 1, the measured value is stored in the storage unit 12
Can be stored in The measurement values stored in the storage unit 12 are transferred to the management computer 15 after the measurement work is completed, and the management processing is performed.

The operation of the armature brush size inspection device 1 of the present invention having the above-described structure is performed generally as follows. (1) The armature brush dimension inspection device 1 of the present invention is set at the position of the armature brush 8 of the electric motor. (2) The movable claw 3 of the movable portion A is moved to be brought into contact with the tip of the armature brush 8 and the dimension of the armature brush 8 is measured. (3) The measured value is stored in the storage unit 12 of the terminal recording device 10. (4) Armature brush 8 stored in the storage unit 12
Transmit the measured values for the dimensions of
The dimensions of the armature brush 8 are maintained and managed.

First, the movable portion A and the fixed portion B of the armature brush size inspection device 1 of the present invention will be described. Figure 3
FIG. 1 is a perspective view of an armature brush size inspection device of the present invention. In the figure, a commutator 9 is a part that is fixed to the shaft of an electric motor and rotates together with the shaft, and the armature brushes 8 are arranged substantially radially and are in contact with the commutator 9.

First, the movable part A will be described. In the figure, the movable part A is installed slidably with respect to the handle 40, and the movable part A has a movable claw 3 that comes into contact with the upper end of the armature brush 8. The movable claw 3 can be slid with respect to the handle 40 together with the main body of the movable section A having the sensor section 4 and the arithmetic processing section 6 as one mode, and abut on the upper end of the armature brush 8. As another aspect, the main body of the movable part A is fixed to the handle 40 and the movable claw 3 is fixed.
Can also be moved.

Next, the fixed portion B will be described. The fixed portion B of the armature brush size inspection device 1 includes a fixed claw 2 and a portion formed in a shape corresponding to the shape of the commutator 9. The fixed claw 2 is for positioning with respect to the armature brush 8, and the portion corresponding to the shape of the commutator 9 is positioned with respect to the commutator 9 to set the reference position for the dimension measurement of the armature brush 8. It is determined. Armature brush 8
In order to measure the dimension, first, while holding the handle 40, the armature brush dimension inspection device 1 is moved to the outer peripheral portion of the commutator 9, and the portion corresponding to the shape of the commutator 9 of the fixed portion is commutated. Contact the surface of the child 9 to determine the length measurement standard,
Next, the movable claw 3 of the movable portion A is brought into contact with the upper end portion of the armature brush 8. Then, the dimension of the armature brush 8 is measured by measuring the distance between the lower end of the fixed portion B and the movable claw 3 of the movable portion A, which is the reference for the length measurement.

Positioning by the fixing portion B will be described in more detail. FIG. 4 is a partial cross-sectional view of a fixed portion of the armature brush size inspection device of the present invention. In order to measure the dimensions of the armature brush 8, the dimension inspection device 1 for the armature brush needs to be accurately positioned with respect to the armature brush 8 and the commutator 9. If the positioning is not performed accurately, the measured value will include an error. Positioning by the fixed portion B includes two positions, that is, positioning on the commutator 9 and positioning on the armature brush 8.

Commutator 9 of the armature brush size inspection device 1
Positioning with respect to is performed by contacting the bottom portion of the fixed portion B with the commutator 9, and the bottom portion of the fixed portion B is formed to correspond to the shape of the commutator 9, and the bottom portion of the fixed portion B is formed. By engaging the shape of the commutator 9 with the shape of the commutator 9, the dimension inspection device 1 for the armature brush can be set and positioned at the correct angle with respect to the commutator 9.

The positioning of the armature brush dimension inspection device 1 with respect to the armature brush 8 portion is performed by bringing the fixing claw 2 of the fixing portion B into contact with the armature brush 8. Here, the normal armature brush 8 is the holder 1
It is supported by 6, and the fixed claw 2 can be brought into contact with the armature brush 8 portion by bringing the contact surface of the fixed claw 2 into contact with the holder 16. The contact between the fixed claw 2 and the holder 16 keeps the distance between the armature brush dimension inspection device 1 and the armature brush 8 constant.

By positioning the armature brush size inspection device 1 with respect to the armature brush 8 and the commutator 9, the armature brush size inspection device 1 can always measure the armature brush 8 at the same position. Next, a measuring method of the dimension inspection device for the armature brush of the present invention will be described. FIG. 5 is a schematic sectional view of the armature brush dimension inspection device of the present invention. In the figure, the fixed portion B is brought into contact with the commutator 9, and the fixed claw 2 of the fixed portion B is brought into contact with the armature brush 8 from the side direction and positioned. At this time, the initial position of the movable claw 3 of the movable portion A is positioned with a gap from the armature brush 8 as shown by the broken line in the figure. After positioning the fixed part B, the movable claw 3 of the movable part A is moved in the direction of the arrow until it contacts the upper end of the armature brush 8. When the movable claw 3 comes into contact with the upper end of the armature brush 8, the distance between the movable claw 3 and the bottom of the fixed portion B becomes the size of the armature brush 8. The calculation processing unit 6 performs length measurement calculation based on the measurement value from the sensor unit 4, and converts it into a digital value in the A / D conversion unit 7.

The zero point alignment in the length measurement is performed by moving the movable part A to the fixed part B side before the length measurement so that the distance is zero, or using the position at the set point in the upper direction of the handle 40 as the reference point. Done by. When the movable portion A is moved to the fixed portion B side and the distance between the movable portion A and the fixed portion B is set to zero, the measured value becomes the dimension of the armature brush 8. On the other hand, when the position at the set point in the upper direction of the handle 40 is used as the reference point,
The dimension of the armature brush 8 is obtained by subtracting the measured value from the distance between the reference point and the bottom of the fixed portion B. The zero point adjustment and the calculation of the measured value are performed in the arithmetic processing unit 6, and which of the zero point adjustments to select can be selected as necessary. Further, the difference from the reference length of the armature brush 8 can be calculated by the calculation processing unit 6 to calculate the wear amount of the armature brush 8. The length measurement data of the size of the armature brush 8 is stored in the storage unit 12 of the terminal recording device 10.

Next, another embodiment of the present invention will be described. FIG. 7 is a schematic sectional view of a dimension inspection apparatus according to the second embodiment of the present invention. In the first embodiment of the present invention described with reference to FIG. 5, the movable claw 3 is moved along with the movable portion A along the handle 40 to bring the movable claw 3 into contact with the upper end of the armature brush 8. However, in the second embodiment, the main body of the movable portion A is in a fixed position without moving along the handle 40, and the movable claw 3 is moved with respect to the main body of the movable portion A. .. In the figure, the movable claw 3 moves in the direction of the arrow from the position indicated by the broken line and comes into contact with the armature brush 8. The zero point adjustment and the calculation of measured values in the second embodiment are the same as those in the first embodiment.

FIG. 8 is a schematic sectional view of a dimension inspection apparatus according to the third embodiment of the present invention. In the third embodiment, the main body of the movable part A is movable along the handle 40, and the movable claw 3 is also movable with respect to the front movable part A. The zero point adjustment in the third embodiment is performed by calibrating the respective values when the movable part A and the movable claw 3 are arranged at the reference positions. In this embodiment, since the main body of the movable part A and the movable claw 3 move together with respect to the handle 40, the calculation of the dimension of the armature brush 8 is performed in the calculation processing part 6 by using both movement amounts. In the third embodiment, the main body of the movable part A is moved to perform the coarse movement, and the movable claw 3 is moved.
The movement of the sword can be used to perform mobilization movement. Therefore, as a usage example of the third embodiment, the movable claw 3 is aligned with a large stroke in accordance with the dimension of the armature brush 8 to be measured in advance by the coarse movement due to the movement of the movable portion A, and the fine movement is performed. The dimension of each armature brush is measured with a minute stroke by the movement. By combining the coarse movement movement and the fine movement movement, it is possible to roughly perform the alignment with a large stroke, and thus it is possible to shorten the measurement time.

In the first to third embodiments, the movable part A and the movable claw 3 are moved manually along the handle 40, and the operator holds the movable part A or the movable claw 3 and This is done by pushing in the direction of the child brush 8. In the following fourth, fifth and sixth embodiments, the movable part A is automatically moved along the handle 40. Figure 9
10 and 10 are sectional views of an automatic moving mechanism of the armature brush size inspection device of the present invention.

A fourth embodiment of the present invention will be described with reference to FIG. In the figure, the movable claw 3 can be automatically moved with respect to the main body of the movable portion A by an automatic movement mechanism. The automatic moving mechanism is composed of, for example, a rack and pinion mechanism and a driving unit, and drives the rack and pinion mechanism by the driving force of the driving unit to move the movable claw 3. As the automatic moving mechanism, any mechanism other than the above mechanism can be used. Further, the start and stop of the automatic moving mechanism can be controlled by a switch installed in the armature brush size measuring device 1 or the terminal recording device 10.

A fifth embodiment of the present invention will be described with reference to FIG. In the figure, the movable portion A that holds the movable claw 3 can be automatically moved with respect to the handle 40 by an automatic movement mechanism. The automatic moving mechanism is composed of, for example, a rack and pinion mechanism and a drive unit in the same manner as described above, and drives the rack and pinion mechanism by the driving force of the drive unit to move the movable claw 3. As the automatic moving mechanism, any mechanism other than the above mechanism can be used. Further, the start and stop of the automatic moving mechanism can be controlled by a switch installed in the armature brush size measuring device 1 or the terminal recording device 10.

As a sixth embodiment of the present invention, by combining the automatic moving mechanisms of the fourth and fifth embodiments, the movable claw 3 can be automatically moved with respect to the movable portion A and the movable portion is moved. It is also possible to automatically move A with respect to the handle 40. Also in this embodiment, the start and stop of the automatic moving mechanism can be controlled by the switch installed in the armature brush size measuring device 1 or the terminal recording device 10.

In the fourth, fifth and sixth embodiments,
The operator starts and stops the automatic moving mechanism by operating a switch. Next, as a seventh embodiment of the present invention, the automatic stopping mechanism will be described. FIG. 11 is a sectional view of a moving mechanism of the armature brush size inspection device of the present invention. In the figure, in the seventh embodiment of the present invention, contact sensors 18, 19 and 20 are installed on the movable claw 3 of the movable part A, the bottom of the fixed part B and the fixed claw 3. The contact sensor 18 is arranged at a position where it comes into contact with the upper end of the armature brush 8, the movable claw 3 or the main body of the movable part A moves along the handle 40, and the movable claw 3 moves to the upper end of the armature brush 8. When it comes into contact with a part, the contact is sensed. The contact signal is input to the automatic movement mechanism to stop driving.

The contact sensor 19 is arranged at a position where it comes into contact with the commutator 9, and the armature brush size measuring device 1
When is moved with the handle 40 and abuts on the commutator 9, the abutment is sensed. The contact signal is input to the display unit 5 or the data display unit 11 to inform the operator that the armature brush size measuring device 1 has contacted the commutator 9. Further, the contact of the armature brush size measuring device 1 with the commutator 9 may be performed by sound or light emission of the light emitting element.

Further, the contact sensor 20 is disposed at a position where it comes into contact with the armature brush 8 or the holder 16, and when the armature brush size measuring device 1 moves with the handle 40 and comes into contact with the commutator 9, the contact sensor 20 comes into contact therewith. Sense contact. The contact signal is input to the display unit 5 or the data display unit 11 to inform the operator that the armature brush size measuring device 1 has contacted the commutator 9. Further, the contact of the armature brush size measuring device 1 with the commutator 9 may be performed by sound from an acoustic element or light emission from a light emitting element. According to this embodiment, the measurer can measure the dimensions of the armature brush without taking an unreasonable posture.

Various sensors such as a pressure sensor and a capacitance sensor can be used as the contact sensors 18 to 20.
An embodiment of the contact sensor of the present invention will be described below. Figure 1
2 is an installation diagram of the contact sensor of the present invention. In the figure, the contact sensors 18 to 20 are constituted by contacts 21. The contact sensor 18 that detects the contact of the movable portion A is arranged at a position where it contacts the upper end of the armature brush 8 of the movable claw 3 and is configured by two contact points 21. When the movable claw 3 moves and comes into contact with the upper end portion of the armature brush 8, the two contact points 21 are short-circuited because the electric resistance of the armature brush 8 is low. The contact can be known by detecting the short circuit of the contact 21.

Contact sensors 19 and 20 for detecting the contact of the fixed portion B with the side portions of the commutator 9 and the armature brush 8.
Are arranged on the bottom portion of the fixed portion B and the fixed claw 2, and are each constituted by two contact points 21. When the bottom portion of the fixed portion B and the fixed claw 2 move and come into contact with the side portions of the commutator 9 and the armature brush 8, the electric resistance of the commutator 9 and the armature brush 8 is low, so the above 2 The two contacts 21 are short-circuited. The contact can be known by detecting the short circuit of the contact 21. Further, the fixed claw 2 is the armature brush 8
When contacting the insulating holder 16 of
In, the contact sensor by the contact 21 can be used by providing the conductor portion at the position where the contact 21 of the fixed claw 3 abuts.

An example of the contact will be described. FIG.
FIG. 4 is a configuration diagram of contacts of the contact sensor of the present invention. In the figure, the contact 21 is constituted by a set of comb-shaped contacts 22. A set of comb-shaped contacts 22 is alternately arranged, and the comb-shaped contacts 2 are arranged.
The contact is detected by short-circuiting the armature brush 8 between the two. By making the contact 21 into a comb shape as described above, the sensing range of the armature brush 8 can be widened.

In the first embodiment of the present invention described with reference to FIGS. 1 and 2, the armature brush size measuring device 1 and the terminal storage device 10 are connected by a cord to measure the armature brush size measuring device 1. The value is stored in the storage unit 12 of the terminal recording device 10 via the code, and the measured value of the storage unit 12 is transmitted to the management computer 15 via the communication line 14. In the following examples, the terminal recording device 1
0 is built in the armature brush size measuring device 1, and the card memory 25 is used as the storage unit 12. FIG. 14 is a block diagram of a portable armature brush size measuring device using the card memory of the present invention. In the figure, the measured value of the armature brush measured by the armature brush dimension measuring device 1 is stored in the card memory 25, and after the measurement is completed, the card memory 25 is taken out and inserted into the management computer 15 to manage the stored data. It is transferred to the computer 15 for use. With this configuration, the armature brush size measuring device 1 does not need to connect the terminal recording device 10 via a cord, and the armature brush size measuring device 1 alone can perform the length measurement work.

Next, the input of measured values to the storage unit 12 will be described. FIG. 15 is a block diagram of a storage unit for measured values. The storage unit 12 stores a measurement value obtained by the length measurement from the sensor unit 4 and information specifying the measurement value. The measured value is converted into a unit of length in the arithmetic processing unit 6, or converted into various desired data formats such as a difference from a reference value and stored in the storage unit 12. On the other hand, information for specifying the measured value is input from the input unit 23 to the arithmetic processing unit 6
It is stored in the storage unit 12 together with the measured value via. As the information for specifying the measured value, there is, for example, information for identifying the measured electric motor, information about the position of the armature brush in the electric motor, or other information about the electric motor or the armature brush. The storage in the storage unit 12 facilitates the management processing in the management computer 15.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0038]

As described in detail above, according to the present invention, the following effects can be obtained. (1) The dimension inspection of the armature brush can be performed by the measurer only by bringing the portable armature brush dimension measuring device of the present invention into contact with the commutator of the electric motor and the armature brush. It is possible to measure in a short time without taking. Therefore, the time and labor required for inspecting the armature brush can be simplified and the work efficiency can be improved. (2) Since the dimension inspection of the armature brush can be performed without visual inspection, it is possible to eliminate measurement value reading errors. (3) It is possible to eliminate variations in measurement accuracy due to individual differences among measurers. (4) There is no risk of mistakes in entering measured values when the measurer writes the measured values in the ledger. (5) It is possible to shorten the transfer work when the measurement result is input to the management computer.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a dimension inspection device for an armature brush of the present invention.

FIG. 2 is a configuration diagram of a terminal recording device of the present invention.

FIG. 3 is a perspective view of an armature brush size inspection device of the present invention.

FIG. 4 is a partial cross-sectional view of a fixed portion of the dimension inspection device for an armature brush of the present invention.

FIG. 5 is a schematic cross-sectional view of an armature brush size inspection device of the present invention.

FIG. 6 is a sectional view of a conventional DC motor.

FIG. 7 is a schematic sectional view of a dimension inspection apparatus according to a second embodiment of the present invention.

FIG. 8 is a schematic sectional view of a dimension inspection apparatus according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional view of an automatic moving mechanism of the armature brush size inspection device of the present invention.

FIG. 10 is a sectional view of an automatic moving mechanism of the armature brush size inspection device of the present invention.

FIG. 11 is a cross-sectional view of a moving mechanism of the armature brush size inspection device of the present invention.

FIG. 12 is an installation diagram of the contact sensor of the present invention.

FIG. 13 is a configuration diagram of contacts of the contact sensor of the present invention.

FIG. 14 is a configuration diagram of a portable armature brush size measuring device using the card memory of the present invention.

FIG. 15 is a block diagram of a storage unit for measured values.

[Explanation of symbols]

 1 Armature Brush Dimension Measuring Device 2 Fixed Claw 3 Movable Claw 4 Sensor 5 Display 6 Calculation Processing 7 A / D Converter 8 Armature 9 Commutator 10 Terminal Recording Device 11 Data Display 12 Memory 13 Switch 14 Communication Line 15 Management computer 16 Holder 18, 19, 20 Contact sensor 21 Contact point 22 Comb type contact point 23 Input section 25 Card memory 40 Handle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Ito 2200 Shimoguri-cho, Utsunomiya-shi, Tochigi Mitutoyo Corporation Utsunomiya Works Sokki factory

Claims (5)

[Claims] 1. A portable armature brush size measuring device for measuring the size of an armature brush mounted on a commutator rotating in a motor, comprising: (a) a fixed portion that abuts against the commutator; A movable part which is relatively displaceable with respect to a fixed part and is in contact with the armature brush; and (c) a calculation for converting the displacement amount of the movable part into an electric signal to measure the dimension of the armature brush. A portable armature brush size measuring device comprising a processing unit. 2. A portable armature brush size measuring device for measuring the size of an armature brush mounted on a commutator rotating in a motor, comprising: (a) a fixed portion that abuts against the commutator; A movable part which is relatively displaceable with respect to a fixed part and is in contact with the armature brush; and (c) a calculation for converting the displacement amount of the movable part into an electric signal to measure the dimension of the armature brush. A portable armature brush size measuring device comprising a processing means and (d) a storage means for storing the output of the arithmetic processing means. 3. The portable armature brush size measuring device according to claim 1, wherein a shape of a portion of the fixed portion which comes into contact with the commutator corresponds to a shape of the commutator. 4. The portable armature brush size measuring device according to claim 1, wherein a portion of the fixed portion that comes into contact with the armature brush has positioning means for positioning the fixed portion with respect to the armature brush. 5. The portable armature brush size measuring device according to claim 2, wherein the storage means is installed in the movable part.