JPH0223070Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electric motor having a rotating shaft provided with a spiral scale having a constant pitch.

More specifically, the present invention relates to an electric motor having a function in which the rotating direction can be visually determined even during high-speed rotation as a result of providing a spiral scale on the rotating shaft.

(Prior Art) In most cases, electric motors are used in rotating equipment used in factory production equipment, laboratories, and the like. Typical examples include agitators, conveyors, pumps, and compressors.

Needless to say, in these rotating devices, not only the number of rotations but also the direction of rotation must be properly controlled.

Among these rotating devices, there are those that do not function at all if they are not rotating in the normal rotation direction, and devices that do not cause much of a problem even if they are not rotating in the normal rotation direction.
Items belonging to the former include conveyors, centrifugal pumps, compressors, etc.; items belonging to the latter include stirrers, plunger pumps, diaphragm pumps, compressors, grinders, etc.

Therefore, in the latter case, as a result of work such as reconnecting the wiring, the driver may not notice if operation continues with the rotation direction set in the opposite direction than the normal rotation direction.

Phenomena that occur in equipment at such times include, for example, the stirring effect of stirrers is different, and unnatural pulsation occurs in pumps, etc. even if pulsation is prevented with an accumulator, and the efficiency of the motor decreases. get up.

(Problem to be solved by the invention) To prevent this from happening, the direction of rotation is usually checked after reconnecting the wiring or other work.

However, factories often forget to check. In such a case, it is necessary to temporarily stop the equipment, press a button, and check the state in which the rotational speed of the motor has decreased.

Also, after reconnecting the wiring, I press the start button momentarily to check the rotation direction.

Even with such instantaneous startup, the electric motor rotates at a fairly high speed, and it takes a considerable amount of time to reach a low speed where the direction of rotation can be confirmed.
The reality is that people are also checking things by touching them with their fingers. In view of this situation, the present inventor has completed the following idea.

(Structure of the invention) That is, the present invention is "an electric motor characterized by providing a rotating shaft with spiral scales having constant regular intervals."

As shown in Fig. 1, the electric motor of the present invention has a certain regular pattern on the exposed part of the rotating shaft of the electric motor, for example, the part that can be observed from the outside between the connection part with the rotating shaft of other equipment and the motor body. It has a spiral scale with intervals.

When the rotating shaft provided with the spiral 6 rotates, the left end 4 (or right end 3) of the spiral appears to move along the rotating shaft and reach the right end 3 (or left end 4).

If the direction of rotation is the same, whether the movement is from left to right or from right to left depends on whether the spiral scale on the rotation axis is applied in the right-handed or left-handed direction. change. Therefore, the apparent movement of the applied spiral scale becomes exactly opposite when the direction of rotation changes.

If the relationship between the direction of this apparent movement and the direction of rotation is displayed in advance on the main body of the electric motor, as mentioned above, even when the electric motor is rotating at high speed, if you check this apparent movement, This makes it possible to determine the direction of rotation. The longer the length of the rotating shaft that provides this spiral scale, the easier it is to confirm the apparent movement.

However, since the electric motor and rotating equipment are usually used in conjunction with each other, a coupling is used, so the rotating shaft of the electric motor is covered by the coupling, and the exposed part is from 30 to 30 mm on the main body side of the electric motor.
It's only 40mm.

However, even if the distance is as short as 30 to 40 mm, by increasing the number of spiral pitches, it is possible to confirm the apparent direction of movement of the spiral scale, that is, the direction of rotation of the motor. . In the case of a double-shaft motor used in an electric grinder, etc., it is preferable to provide spiral scales on both sides.

Next, it will be explained how many pitches the spiral scale should have in this section of about 30 to 40 mm to determine the apparent direction of movement of the spiral scale.

In FIG. 1, for example, the right end 3 of the spiral scale 6
Let's consider the case where there is an apparent movement toward the left end 4. Here, the following relationship holds between the rotational speed (rpm) of the electric motor, the pitch number (N) of the spiral scale provided, and the time (seconds) required for the apparent movement.

Rotation speed (rpm) = 60/T×N (1 set) By the way, there are three types of rotation speed for industrially used electric motors: 3500 rpm, 1750 rpm, and 850 rpm for AC 60 Hz, depending on the number of poles of the motor rotor. is the most common. For example, the highest RPM
3500rpm, the distance of the spiral scale on the rotating shaft is
Assuming that the distance is 30 mm and the number of pitches is 50, the T (seconds) and pitch interval of one equation are calculated as follows.

T (seconds) = 60 x 50/3500≒1 Pitch interval (mm) = 30/50 = 0.6 In other words, the spiral scale with a pitch interval of approximately 0.6 mm is 30 mm
If it is applied to the application section 5, it is possible to visually confirm that the spiral scale 6 is apparently moving toward the left end 4. In other words, the direction of rotation of the electric motor, which is rotating at a high speed of 3500 rpm, can be confirmed.
Therefore, when the number of revolutions is lower than this, the area on which the spiral scale is applied may be shortened, or the number of pitches of the scale may be reduced.

Considering the accuracy and preservation of the scale, it is best to permanently apply the spiral scale to the rotating shaft of the electric motor using a lathe. A label with diagonal lines may be wrapped around the rotating shaft and attached to form a spiral scale.

The spiral scale given to the rotating shaft is 0.6mm even if carved by a lathe, as mentioned above.
Since the distance between the two is relatively narrow, dust and dirt may adhere to it, making it difficult to distinguish between the two. In such a case, it is convenient to color the rotary shaft body and the spiral with fluorescent paint or the like so that they can be distinguished from each other, and then cover the surface with a transparent coating layer, tape, etc.

It goes without saying that the principle of the present invention is not limited to electric motors, but can be applied to the rotating shafts of other rotating devices, and can also be applied to measuring not only the direction of rotation but also the number of rotations.

(Effects of the invention) The electric motor of the invention has the following advantages compared to conventional motors.

B The direction of rotation can be visually confirmed even while rotating at high speed.

(b) If the pitch number of the spiral scale provided on the rotating shaft is displayed on the main body, the approximate rotation speed can be determined by measuring the apparent travel time of the spiral scale.

[Brief explanation of drawings]

FIG. 1 shows a scale-applied portion of a rotary shaft provided with a spiral scale of the electric motor according to the present invention.

Claims (1)

[Scope of utility model registration request] An electric motor characterized in that a rotating shaft is provided with spiral scales having regular intervals.