DRIVING APPARATUS

Abstract

A driving apparatus that can be made compact, without increasing the number of component parts and decreasing diameters of a rotating shaft and bearings. When a first unit assembled from a first stator and a first bobbin is coupled to a second unit assembled from a second stator and a second bobbin, engaging portions of the first bobbin are caused by a first switching member to shift from a disengaged state from the first stator to an engaged state with the first stator, and a second switching member, and engaging portions of the second bobbin are caused by a second switching member to shift from a disengaged state from the second stator to an engaged state with the second stator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing the construction of a stepping motor as a driving apparatus according to a first embodiment of the present invention;

FIG. 2A is a fragmentary development view showing outer magnetic pole portions of a first stator in the stepping motor shown in FIG. 1;

FIG. 2B is a fragmentary development view showing jaw portions of a first bobbin in the stepping motor shown in FIG. 1;

FIG. 3A is a fragmentary development view showing outer magnetic pole portions of a second stator and jaw portions of a second bobbin in the stepping motor shown in FIG. 1;

FIG. 3B is a fragmentary development view showing the outer magnetic pole portions of the first stator and the jaw portions of the first bobbin in the stepping motor shown in FIG. 1;

FIG. 3C is a fragmentary development view showing the outer magnetic pole portions of the first and second stators and the jaw portions of the first and second bobbins in the stepping motor shown in FIG. 1;

FIG. 4 is an exploded perspective view showing the construction of a stepping motor as a driving apparatus according to a second embodiment of the present invention;

FIG. 5A is a fragmentary development view showing outer magnetic pole portions of a second stator of the stepping motor in FIG. 4;

FIG. 5B is a fragmentary development view showing jaw portions of a second bobbin of the stepping motor in FIG. 4;

FIG. 6A is a fragmentary development view showing the outer magnetic pole portions of the second stator and the jaw portions of the second bobbin of the stepping motor in FIG. 4;

FIG. 6B is a fragmentary development view showing outer magnetic pole portions of a first stator and jaw portions of a first bobbin of the stepping motor in FIG. 4;

FIG. 6C is a fragmentary development view showing the outer magnetic pole portions of the first and second stators and the jaw portions of the first and second bobbins of the stepping motor in FIG. 4;

FIG. 7 is an exploded perspective view showing the construction of a stepping motor proposed by the assignee of this application; and

FIG. 8 is a sectional view of the stepping motor shown in FIG. 7.

Claims

1. A driving apparatus comprising: a cylindrical magnet circumferentially magnetized;a first stator for being excited by a first coil;a second stator for being excited by a second coil;a first bobbin for fixing said first coil, said first bobbin including at least one first engaging portion for being shifted between a disengaged state from said first stator and an engaged state with said first stator;a second bobbin for fixing said second coil, said second bobbin including at least one second engaging portion for being shifted between a disengaged state from said second stator and an engaged state with said second stator;at least one first switching member for shifting said first engaging portion of said first bobbin from the disengaged state from said first stator to the engaged state with said first stator when a first unit assembled from said first stator and said first bobbin is coupled to a second unit assembled from said second stator and said second bobbin; andat least one second switching member for shifting said second engaging portion of said second bobbin from the disengaged state from said second stator to the engaged state with said second stator when the first unit is coupled to the second unit.

2. The driving apparatus according to claim 1, wherein said first switching member is provided in said second stator, and said second switching member is provided in said first stator; when said first stator is coupled to said second bobbin, said second switching member provided in said first stator causes the second engaging portion of said second bobbin to shift from the disengaged state from said second stator to the engaged state with said second stator; andwhen said second stator is coupled to said first bobbin, said first switching member provided in said second stator causes the first engaging portion of said first bobbin to shift from the disengaged state from said first stator to the engaged state with said first stator.

3. The driving apparatus according to claim 2, wherein said first stator includes a first stator base portion and a plurality of first tooth-shaped magnetic pole portions axially extending from said first stator base portion, at least one of said first magnetic pole portions having a tip end portion thereof forming said second switching member; said second stator includes a second stator base portion and a plurality of second tooth-shaped magnetic pole portions axially extending from said second stator base portion, at least one of said second magnetic pole portions having a tip end portion thereof forming said first switching member;said first bobbin includes a first bobbin base portion and a plurality of tooth-shaped first jaw portions thereof axially extending from said first bobbin base portion and each having opposite side edges, at least one of said first jaw portions being provided with said first engaging portion in at least one of the opposite side edges thereof, each of said first magnetic pole portions being inserted between corresponding adjacent ones of said first jaw portions, and said at least one first jaw portion or at least one different first jaw portion being formed with at least one first recess into which said first switching member formed by the tip end portion of said second magnetic pole portion can be inserted;said second bobbin includes a second bobbin base portion and a plurality of tooth-shaped second jaw portions thereof axially extending from said second bobbin base portion and each having opposite side edges, at least one of said second jaw portions being provided with said second engaging portion in at least one of the opposite side edges thereof, each of said second magnetic pole portions being inserted between corresponding adjacent ones of said first jaw portions, and said at least one first jaw portion or at least one different first jaw portion being formed with at least one second recess into which said second switching member formed by the tip end portion of said first magnetic pole portion can be inserted.

4. The driving apparatus according to claim 1, wherein said first switching member is provided in said second bobbin, and said second switching member is provided in said first bobbin; when said first bobbin is coupled to said second bobbin, said second switching member provided in said first bobbin causes the second engaging portion of said second bobbin to shift from the disengaged state from said second stator to the engaged state with said second stator; andwhen said second bobbin is coupled to said first bobbin, said first switching member provided in said second bobbin causes said first engaging portion of said first bobbin to shift from the disengaged state from said first stator to the engaged state with said first stator.

5. The driving apparatus according to claim 4, wherein said first stator includes a first stator base portion and a plurality of tooth-shaped first magnetic pole portions axially extending from said first stator base portion; said second stator includes a second stator base portion and a plurality of tooth-shaped second magnetic pole portions axially extending from said second stator base portion;said first bobbin includes a first bobbin base portion and a plurality of tooth-shaped first jaw portions thereof axially extending from said first bobbin base portion and each having opposite side edges, at least one of the first jaw portions being provided with said first engaging portion in at least one of the opposite side edges thereof, each of said first magnetic pole portions being inserted between corresponding adjacent ones of said first jaw portions, and said at least one first jaw portion or at least one different first jaw portion has a tip end portion thereof forming said second switching member;said second bobbin includes a second bobbin base portion and a plurality of tooth-shaped second jaw portions thereof axially extending from said second bobbin base portion and each having opposite side edges, at least one of said second jaw portions being provided with said second engaging portion in at least one of the opposite side edges thereof, each of said second magnetic pole portions being inserted between corresponding adjacent ones of the second jaw portions, and said at least one second jaw portion or at least one different second jaw portion has a tip end portion thereof forming said first switching member;said first bobbin is formed with at least one first recess into which the tip end portion of the second jaw portion of said second bobbin forming said first switching member can be inserted; andsaid second bobbin is formed with at least one second recess into which the tip end portion of the first jaw portion of said first bobbin forming said second switching member can be inserted.

6. The driving apparatus according to claim 1, wherein said first and second stators each include tooth-shaped magnetic pole portions axially extending; and said first and second bobbins each include tooth-shaped jaw portions axially extending.