JPS628416Y2 - - Google Patents

Description

[Detailed explanation of the idea] 〔Technical field〕 This invention relates to a motor shaft.

[Background technology]

In a motor rotor, when a laminated iron core 1 is fixed to a motor shaft 2 as shown in FIG. A motor shaft 2 having a plurality of crushing ridges 3 formed in the circumferential direction is used, and the iron core 1 is stretched to the extent that the crushing ridges 3 are submerged.
The iron core 1 was fixed by press-fitting the mounting hole into the cylindrical rod.

However, the height of the crushing protrusion 3 of the motor shaft 2 that has been deformed due to soaking is h1>h2 due to the conditions at the time of press-fitting the iron core 1, etc., and is not the same for all (Figs. 3 and 4). (Fig.), therefore, there was a drawback that an eccentric amount e occurred between the center of the iron core 1 and the center of the motor shaft 2.

On the other hand, if the number of crushing ridges 3 in the circumferential direction is increased, it is possible to reduce the eccentricity e;
The press-fit resistance of the iron core 1 increases.

[Purpose of invention]

The purpose of this invention is to provide a motor shaft that can reduce the eccentricity of the iron core without increasing the press-fit resistance of the iron core.

[Disclosure of invention]

The motor shaft of this invention has a plurality of crushing ridges of a predetermined length parallel to the axial direction formed on the surface of the cylindrical rod at equal intervals in the circumferential direction, and two sets of the same configuration. This is characterized in that they are formed separately from each other in the axial direction, and the crushing ridges of the sets are formed offset from each other in the circumferential direction.

According to the configuration of this invention, one set of crushing ridges and another set of crushing ridges formed at equal intervals in the circumferential direction are formed offset from each other in the circumferential direction. Since the eccentric direction of the iron core due to one set of crushing ridges and the eccentric direction of the iron core due to the other set of crushing ridges are rarely in the same direction, the components of the eccentric directions in opposite directions cancel each other out. The overall eccentricity of the iron core is reduced. Further, since the crushing ridges are crushed by the iron core one by one for each group, the press-fitting resistance of the iron core does not increase.

Embodiment An embodiment of this invention will be described based on FIGS. 5 to 7. In other words, this motor shaft is
A plurality of crushing protrusions 4a, 4b of a predetermined length parallel to the axial direction are formed on the surface of the cylindrical rod 5 at equal intervals in the circumferential direction, and two or more sets of the same configuration are formed in the axial direction. They are formed separately from each other, and the crushing ridges 4a, 4b of the pair are formed to be offset from each other in the circumferential direction.

The crushing protrusions 4a and 4b are serrations, and are arranged at equal intervals in the circumferential direction of the cylindrical rod 5.
They are machined one by one, and the ones lined up in the axial direction are offset by about 45 degrees in the circumferential direction.

Because of this configuration, when an iron core having a configuration similar to that shown in FIG. 1 (not shown) is press-fitted into the motor shaft, the crushing protrusions 4a and 4b are crushed and fixed by the installation holes of the iron core, respectively. . At this time,
Since the number of crushing ridges 4a and crushing ridges 4b is the same as in the conventional example, the press-fit resistance is the same.

Furthermore, since the crushing ridges 4a and 4b are offset in the circumferential direction, the eccentric direction of the set of crushing ridges 4a of the iron core and the eccentric direction of the set of crushing ridges 4b of the iron core are almost never the same. Therefore, the components in the opposite directions of eccentricity cancel each other out, and the eccentricity of the iron core as a whole can be reduced compared to the conventional example in which only one set of crushing ridges 4a exists.
In other words, when press-fitting an iron core into a motor shaft, even if the set of crushing ridges 4a to be crushed first is eccentrically press-fitted at a position determined by the crushing resistance of each crushing ridge, the iron core will remain as it is. It is not press-fitted into the next set of crushing ridges 4b in an eccentric state, and includes the center of the motor shaft determined by the dipping resistance of each crushing ridge in the next set of crushing ridges 4b. Try to be eccentric in position. In this case, since the eccentric position caused by the first set of crushing ridges 4a and the eccentric position due to the next set of crushing ridges 4b are almost never the same, the iron core is Even if the iron core is eccentric, the eccentric action of the next set of crushing protrusions 4b causes the iron core to approach the center of the motor shaft from the initial eccentric position, and the eccentricity of the iron core as a whole is alleviated. It will become.

Also, compared to the case where the total number of crushing ridges 4a and 4b, that is, eight pieces, are formed in the circumferential direction, after the set of crushing ridges 4a is crushed by the iron core, the crushing ridges 1
Since group b is crushed, the press-fit resistance of the iron core does not increase.

A second embodiment of this invention is shown in FIG. That is, this motor shaft has a plurality of sets of a plurality of crushing ridges 6 arranged at equal intervals in the circumferential direction in the axial direction,
Each set is shifted from each other in the circumferential direction in stages.

According to this embodiment, since the eccentric directions of the iron core by the crushing ridges 6 of each set are formed in different directions, it is possible to further reduce the eccentricity of the iron core.

Note that the crushing protrusions may be not only serrations but also knurlings.

[Effect of idea]

According to the motor shaft of this invention, one set of crushing ridges and another set of crushing ridges formed at equal intervals in the circumferential direction are formed to be offset from each other in the circumferential direction. Therefore, the eccentric direction of the iron core due to one set of crushing ridges and the eccentric direction of the iron core due to the other set of crushing ridges are almost never in the same direction, so the components of the eccentric directions in opposite directions cancel each other out. As a result, the overall eccentricity of the iron core is reduced. Furthermore, since the crushing ridges are crushed by the iron core one by one for each group, there is an effect that the press-fitting resistance of the iron core does not increase.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of the rotor, Fig. 2 is a side view of its motor shaft, Fig. 3 is a partial cross-sectional view showing the press-fitted state of the iron core, Fig. 4 is a cross-sectional view thereof, and Fig. 5 is a side view of the motor shaft. 6 is a side view of the first embodiment of the invention, FIG. 6 is a cross-sectional view taken along the line --, FIG. 7 is a cross-sectional view taken along the line -- of FIG. 5, and FIG. 8 is a side view of the second embodiment. 5... Cylindrical rod, 4a, 4b, 6... Crushing protrusion.

Claims (1)

[Claims for Utility Model Registration] (1) A cylindrical rod having the same configuration as a cylindrical rod, in which a plurality of crushing ridges of a predetermined length parallel to the axial direction are formed on the surface of the rod at equal intervals in the circumferential direction. A shaft for a motor, characterized in that two or more sets are formed separately from each other in the axial direction, and the crushing ridges of the sets are formed offset from each other in the circumferential direction. (2) The motor shaft according to claim 1, wherein the crushing protrusion is a serration. (3) The motor shaft according to claim (1), wherein the crushing protrusion is a knurl.