Machine tool and detachable/attachable motor

=== Fourth Embodiment of the Machine Tool ===

[0169] In the connecting structure according to the first embodiment, the peripheral portion of the fitting projection 63a of the drive shaft 63 has been chamfered so that, when fitting into the fitting depression 41a of the input shaft 41, slight deviation in the axial positions or the rotation angle between the two can be permitted and the fitting projection 63a can be quickly guided into the fitting depression 41a. The fourth embodiment is an improvement in that the tolerance of this deviation is increased further.

[0170]FIG. 17 and FIG. 18 are explanatory diagrams of the connecting structure according to the fourth embodiment. FIG. 17 is a center vertical sectional view of the connecting structure. FIG. 18 is a center vertical sectional view showing the connecting process; in its left half the state immediately prior to connection is shown, and in its right half the connected state is shown. It should be noted that in FIGS. 17 and 18 the

=== First Embodiment of the Detachable / Attachable Motor ===

[0180]FIG. 20 and FIG. 21 are vertical sectional views for describing a detachable / attachable motor 2061 according to a first embodiment of the present invention. FIG. 20 shows a state in which a rotor 2063 of the detachable / attachable motor 2061 has been disconnected from a driven rotation shaft 2041, and FIG. 21 shows the connected state. It should be noted that a portion of the rotor 2063 and the driven rotation shaft 2041 are shown as a side view.

[0181] The detachable / attachable motor 2061 is for applying a rotational force to the driven rotation shaft 2041 by coaxially and detachably connecting the rotor 2063 of the detachable / attachable motor 2061 to a suitable driven rotation shaft 2041 that is supported in a manner that permits rotation about its axis C2041.

[0182] That is, a depression 2063a that engages with a projection 2041a formed on an end section of the driven rotation shaft 2041 and transmits rotation

=== Second Embodiment of the Detachable / Attachable Motor ===

[0198] The detachable / attachable motor 2061 of the first embodiment is a so-called synchronized type (SM type) AC servo motor in which the rotor 2063 is provided with the permanent magnet 2067. A detachable / attachable motor 2161 according to this second embodiment differs from this in that instead it is a so-called induction type (IM type) AC servo motor in which the rotor 2063 is provided with coils.

[0199]FIG. 22 shows a vertical sectional view of the detachable / attachable motor 2161 according to this second embodiment. It should be noted that in this drawing, the driven rotation shaft 2041 and a portion of the rotor 2063 are shown as a side view. Components that are identical to those of the detachable / attachable motor 2061 according to the first embodiment are shown assigned identical reference numerals and description thereof is omitted.

[0200] A plurality of coils 2167 are disposed in the circumferential direct