A super-minuature motor used as a driving motor in super-precision miniature machines is disclosed. The motor is constructed from a rotating member 1 made from a permanent magnet, actuators 8-13 which can be moved or displaced by a charged energy, and starters 2-7 made from a magnetic material which are surrounding the outer periphery of the rotating member and movable along with the movement of the actuators toward the direction of the diameter. This construction enables a super-minuature motor to be manufactured even smaller and to minimize the electricity consumption of the motor.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a super-minuature motor used as a driving 
motor in super-precision minuature machines and the like and, 
particularly, to a super-miniature pulse motor which is miniaturized by 
excluding exciting coils. 
2. Background Art 
Conventionally, driving motors for super-precision miniature machines, for 
example, miniature motors used as driving motors of quartz crystal 
watches, are constructed, in the same manner as in large motors, from 
exciting coils consisting of copper wires wound around a part of a stators 
such that the motor is rotated by a driving force created by charging an 
exiting current to the exciting coils. 
Thus, exciting coils are required for conventional miniature motors to 
generate a driving force. In the case where the exciting coils are used, a 
considerable number of windings is required for the coils. If the diameter 
of the wires for the coils is reduced to as small as 10 .mu.m or less for 
the purpose of miniaturization of the motors, the coils tend to be easily 
broken, making it extremely difficult to wind the coils around the 
starter. 
Accordingly, the exciting coils must be inevitably thick and large, and it 
is very difficult to miniaturize motors as a whole. 
An object of the present invention is therefore to provide a 
super-miniature motor which is miniaturized by excluding exciting coils, 
which prevents motors from being miniaturized. 
DISCLOSURE OF THE INVENTION 
The super-miniature motor of the present invention is constructed from a 
rotating member made from a permanent magnet, actuators which can be moved 
or displaced by a charged energy, and stators made from a magnetic 
material which are surrounding the outer periphery or both the upper and 
bottom surfaces of the rotating member, and movable along with the 
movement of the actuators in the radial direction of the motor. 
A plural number of actuators are successively charged with a voltage as an 
energy source for changing distances between the corresponding stators and 
the rotating member to change a magnetic suction force. This change in the 
magnetic suction force causes the rotating member to rotate either 
clock-wise or counter clock-wise direction of the rotation axis thereof. 
In the super-miniature motor of the present invention in which the driving 
force is acquired by changing gaps between the rotating member and the 
stators by the actuators which can be moved or displaced by a charged 
energy, there are no need for a larger-sized exciting coil for charging an 
exiting current. Thus, a super-miniature motor which is even smaller than 
existing small-sized motors can be provided by the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION 
The embodiments of present invention is hereinafter described referring to 
the drawings. The present invention shall not be construed as being 
limited by these embodiments. 
In FIGS. 1 and 2, there are shown plan views of the first embodiment of the 
super-miniature motor, in which FIG. 1 shows the state where the motor is 
at rest and FIG. 2 shows the state when the motor is rotated by one step. 
As shown in FIG. 1, rotating member 1, consisting of a permanent magnet 
having a pair of magnetic poles, which are N-pole and S-pole, is provided 
rotatably around a rotation axis 15. Stators 2, 3, 4, 5, 6, and 7 are 
arranged so as to surround the outer periphery of rotating member 1. 
Further, provided outside these stators are actuators 8, 9, 10, 11, 12, 
and 13, for example, of piezoelectric members, each corresponding to 
stators 2, 3, 4, 5, 6, and 7, respectively. Each end, i.e. inner end, of 
these actuators 8, 9, 10, 11, 12, and 13 is adhered to each of the 
corresponding stators 2, 3, 4, 5, 6, and 7, respectively, and each other 
end, i.e. outer end of the actuators is connected to a frame 14. Since the 
actuators 8, 9, 10, 11, 12, and 13 are made of piezoelectric members, when 
electricity is applied to the actuators, the actuators are moved in the 
direction of the diameter as shown by arrows. Although not shown in FIG. 
1, the actuators are constructed so as to move back and fourth in the 
direction of the diameter by charging a voltage between two electrodes of 
the piezoelectric member of each actuator. Rotating member 1 is at rest in 
a stable manner at a place where the magnetic potential in the magnetic 
circuit constructed by the rotating member 1 and the stators 2, 3, 4, 5, 
6, and 7 is minimum. Supposing that the N-pole of rotating member 1 is at 
gap 16 between the stators 6 and 7, and the S-pole is at gap 17 between 
the stators 3 and 4, as shown in FIG. 1, one of the magnetic flux from the 
N-pole of rotating member 1 returns to the S-pole via the stators 6, 5, 4, 
and the other magnetic flux returns to S-pole via the stators 7, 2, 3. 
Interim gaps between the stators in either course are two, and are thus 
minimized. Accordingly, the magnetic resistances and the magnetic 
potentials are minimized. 
On the other hand, if the N-pole of rotating member 1 is positioned at the 
center of starter 7 and the S-pole at the center of starter 4, one of the 
magnetic flux from the N-pole of rotating member 1 returns to the S-pole 
via the stators 7, 6, 5, 4, and the other magnetic flux returns to the 
S-pole via the stators 7, 2, 3, 4. Interim gaps between the stators in 
both courses are three. Because of this, the magnetic resistances and the 
magnetic potentials are large, and the rotating member cannot stand still 
at this point. The stable points, therefore, coincide to the place of gaps 
between the stators. 
In a condition as shown in FIG. 1, if a voltage is applied to actuators 9 
and 12, i.e. piezoelectric members, via electrodes, not shown in the 
Figure, so as to contract these actuators 9 and 12 along the direction of 
the diameter, the stators 3 and 6 are moved externally according to the 
movements or contractions of actuators 9 and 12, respectively. This 
expands the gap between the N-pole of rotating member 1 and starter 6, and 
the gap between the S-pole of rotating member 1 and starter 3, so that the 
magnetic resistances between these gaps become large. 
Because the magnetic resistance between the N-pole of rotating member 1 and 
starter 7 and the magnetic resistance between the S-pole of rotating 
member 1 and starter 4 remain the same, a gradient in the magnetic 
potential is created so as to decrease the overall magnetic resistance. 
As a result, rotating member 1 rotates clockwise by one step (60.degree.) 
due to the rotational force, and, as shown in FIG. 2, stably rests at a 
point from gap 18 between the stators 7 and 2 and gap 19 between the 
stators 4 and 5, where the magnetic resistance is minimum. 
The voltage may be applied to the actuators until the time when the 
rotating member rests stationary, or it may be applied for a shorter 
period of time. 
The voltage application to actuators 9 and 12 is then terminated to return 
the stators 3 and 6 to the original positions, while a voltage is applied 
to actuators 10 and 13 to move the stators 4 and 7 outwardly for rotating 
the rotating member by one step of 60.degree. in the same manner as above. 
The rotating member is thus rotated one round in six steps. 
FIGS. 3-6 are drawings showing the super-miniature motor of the second 
embodiment of the present invention, wherein FIGS. 3 and 4 are a sectional 
view and a plan view, respectively, while the motor is at rest; and FIGS. 
5 and 6 are a sectional view and a plan view when the motor is rotated by 
one step. The second embodiment is now illustrated with reference to FIGS. 
3, 4, 5, and 6. 
As shown in FIG. 3, the rotating element 21 consisting of a permanent 
magnet having two pairs of poles, four poles in total, two N-poles and two 
S-poles, being directed to the axis, is provided rotatably around a 
rotation axis 40. Further provided above an upper surface and below a 
bottom surface of the rotating member 21 are six stators, 22 (22a, 22b), 
23 (23a, 23b), 24 (24a, 24b), 25 (25a, 25b), . . ., each consisting of a 
magnetic material. Still further provided corresponding respectively to 
the stators 22, 23, 24, 25, . . . , are actuators, 28 (28a, 28b), 29 (29a, 
29b), 30 (30a, 30b), 31 (31a, 3lb), . . ., consisting, for example, of 
piezoelectric element. Each one of the terminals of these actuators, 28, 
29, 30, 31, . . . is respectively adhered to each of the stators 22, 23, 
24, 25, . . ., and the other terminal is adhered to frame 14. 
FIG. 4 is a plan view sectioned along the plane 4-4 of FIG. 3. 
In the same manner as the first embodiment described referring to FIGS. 1 
and 2, the N-pole of rotating member 21 shown in FIG. 4 stands still at 
gap 41 between the stators as the stationary point, and the S-pole stands 
still at gap 42 as the stationary point. Here, a sectional view sectioned 
along the plane 3--3 corresponds to the sectional view shown in FIG. 3. 
As shown in FIG. 5, when a voltage is applied so as to contract actuators 
30a, 30b (and 33a, 33b) corresponding to stators 24a, 24b and the starters 
axially asymmetric to these stators (starters 27a, 27b shown in FIG. 6), 
in the axial direction, gaps from the stators 24a, 24b, 27a, 27b to 
rotating member 21 are expanded and magnetic resistances are caused to 
change, as discussed in connection with the first embodiment. The change 
in the magnetic potential thus produced creates a rotational force, which 
rotates rotating member 21 by 60.degree. and causes it to stand still at 
stationary points 43, 44, as shown in FIG. 6. 
Then, the stators 24a, 24b, 27a, 27b are returned to the original 
positions, while the stators 23a, 23b, 26a, 26b are moved. Thus, rotating 
member 21 is rotated one round in six steps in the same manner as in the 
first embodiment. 
Although examples in which six or twelve stators are used are illustrated 
in the first and second embodiments above, the number of the stators are 
not limited to six or twelve. The use of minimum two stators is possible, 
if the time for which a voltage is applied to the actuators is 
appropriately selected. Also, the stators are not limited to those with 
two or four poles. Any the stators with more than a single pole (N pole or 
S pole) can be used. 
It is possible to change the output of the motors in these embodiments by 
altering gaps between the rotating member and the stators through the 
change in the voltage applied to the actuators which are moved or 
displaced along with the starters. 
Any materials exhibiting piezoelectric characteristics, such as 
piezoelectric ceramics (barium titanate, lead zirconate-tatanate, 
mult-component solution ceramics), monocrystals of barium titanate, quartz 
crystals, Rochelle salts, and the like can be used as a piezoelectric 
material for the actuators in these embodiments. 
Further, it is possible to fabricate the combination of stators and 
actuators as monomorph, unimorph, bimorph, or multimorph of bending 
displacement type or as linear displacement lamination type, in order to 
widen the degree of displacement of the stators and to reduce the driving 
voltage. 
The super-miniature motors of the present invention are not necessarily 
limited to pulse motors. It is possible to fabricate continuous motors by 
continuously applying the voltage. In particular, fabrication of a 
continuous motor with a low electricity consumption is possible if a 
resonance frequency by the stators and actuators is used. 
Although embodiments using a piezoelectric element as actuators are 
illustrated in the descriptions above, any materials which can be moved or 
displace by input energy, such as a shape memory alloy, can be used as a 
material for the actuators. 
Furthermore, although embodiments illustrated above are related to those 
using a permanent magnet as the rotating member and a magnetic material as 
the stators, it is possible to use a magnetic material as the rotating 
member and a permanent magnet as the stators. 
INDUSTRIAL APPLICABILITY 
As illustrated above, the super-miniature motor of the present invention 
can be used as a driving motor for quartz crystal watches, robots for 
medical and welfare applications, medical mechatronics, microrobots, and 
the like.