JPH0619310Y2 - Stepping motor with damper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a stepping motor with a damper having improved static characteristics.

(Prior Art) Stepping motors are used for various purposes and act to intermittently rotate a load. Since this stepping motor operates in a vibrational manner in principle, it causes a vibration as shown in FIG. 3 when the rotation is stopped, and there is a problem that it takes a lot of time to completely stop at a regular position. In the past, in order to solve this problem, a vibration damping force is electrically exerted by a drive circuit, or a mechanical damper (magneto damper or oil damper) is externally attached to the rotary shaft to reduce vibration. We are trying to reduce the time. As described above, unless braking is performed by any means, it takes time for the rotor to completely stop naturally, which causes a problem that rapid processing cannot be performed.

(Problems to be Solved by the Invention) As described above, since the stepping motor itself cannot perform quick braking, it is usual to take some braking means. However, in order to exert the electric vibration suppression force as described above, it is necessary to provide a separate drive circuit, and in order to externally attach the mechanical damper, the structure becomes complicated and required. There was a problem that the space became large. The present invention has been made in view of this point.

(Means for Solving the Problems) As a means for solving the above problems, the present invention provides a stepping motor with a damper in which a rotor is rotatably supported by a bearing provided in the motor case, In a stepping motor in which a magnet and an iron core are attached to the rotor shaft inside to form a rotor, the iron core is hollowed out from its outer end surface in a direction along the rotor shaft, and the hollowed portion is hollow. A body container is fitted and attached, and a viscous fluid is filled in the container together with an inertial body.

(Operation) With such a configuration, when the rotor is stopped, the inertial force of the inertial body as a damper and the inertial force of the rotor of the motor are adjusted by the inertial body and the viscous fluid attached to the rotor. Therefore, it is possible to absorb the vibration generated in the process of reaching the complete stop in an extremely short time as compared with the conventional one. Therefore, complete stop can be performed in a short time. Further, since the hollow container for filling the inertial body and the viscous fluid is attached to the iron core, the iron core is hollowed and attached to that portion, so that the rotor inertia is the same as before the attachment. Further, it is not necessary to increase the volume inside the motor case for the damper, and it is not necessary to lengthen the rotor shaft outside the motor case as in the case where the damper is attached to the outside of the motor case.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.
In the figure, reference numeral 1 denotes a rotor shaft, which is rotatably supported by bearings 3 and 4 provided on both sides of a motor case 2 as shown in FIG. A magnet 5 is attached to the center of the rotor shaft 1 inside the motor case 2, and iron cores 6 and 7 are integrally attached to both sides of the magnet 5. As shown in FIG. 2, a stator iron core 9 around which a stator coil 8 is wound is attached to a portion located inside the motor case 2 and outside the magnet 5 and the iron cores 6 and 7. There is.

As shown in FIG. 1, the iron cores 6 and 7 are provided with notches 6a and 7a by cutting out from the outer end surfaces in the direction along the rotor shaft 1. The notches 6a and 7a are hollow. A body container 10 is fitted and attached. The container 10 is filled with the inertial body 11 and the viscous fluid 12. The inertial body 11 is preferably a metal such as iron having a large specific gravity,
The viscous fluid 12 preferably has an appropriate viscosity such as oil. The inertial body 11 and the viscous fluid 12 form a damper.

When the stepping motor configured as described above is stopped by stopping the energization, basically, the same vibration as that of the conventional one, in which the rotation direction is alternately changed, is generated. The viscous friction between the viscous fluid 12 surrounding the inertial body 11 and the inertial body 11 always receives a force (resistive force) in the opposite direction, which cancels the vibrations and absorbs the vibrations. Therefore, inertial body 11 and viscous fluid
The ratio of the inertia of the inertial member 11 of the damper 12 and the inertia of the motor rotor (mainly the magnet 5 and the iron cores 6 and 7) is increased, and the vibration absorption effect is improved.
FIG. 3 shows this characteristic.

(Effect of the Invention) Since the present invention is configured as described above,
With a simple structure, it is possible to effectively absorb the vibration when stopped. And in order to mount a hollow container filled with an inertial body and viscous fluid, I tried to pull out the iron core and attach it to that part, so unlike the conventional simple external attachment,
Another feature is that the moment of inertia after mounting is the same as before mounting. In addition, no special drive circuit is required unlike the conventional one that electrically exerts a vibration suppressing force, and the external dimensions are not increased as in the case where an external mechanical damper is provided on the rotor shaft. Therefore, it is possible to sufficiently deal with applications such as OA equipment that is housed in a limited volume.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an essential part of one embodiment of the present invention, FIG. 2 is a cross-sectional view showing the relationship with the motor case of FIG. 1, and FIG.
The figure is a characteristic diagram showing characteristics of the present invention and the conventional one. 1 ... Rotor shaft, 2 ... Motor case 5 ... Magnet, 6,7 ... Iron core 10 ... Container, 11 ... Inertia 12 ... Viscous fluid

Claims (1)

[Scope of utility model registration request] 1. A stepping motor in which a rotor shaft is rotatably supported by a bearing provided in a motor case and a rotor is formed by attaching a magnet and an iron core to the rotor shaft inside the motor case. , The iron core is gouged in a direction along the rotor axis from the outer end surface of the iron core, a hollow container is fitted into the gouged portion, and the viscous fluid is filled in the container together with the inertial body. A stepping motor with a damper, characterized in that the rotor inertia after mounting the damper does not increase compared to before mounting.