Motor

Details Motor Motor

1999-04-16

2002-06-04

Waks, Joseph (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

Reexamination Certificate

active

06400055

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a motor constructed super-compactly.
2. Related Background Art
Heretofore, as a motor formed as a compact motor, there is, for example, a compact cylindrically shaped step motor as shown in
FIG. 24
of the accompanying drawings.
In
FIG. 24
, this motor is provided with two stators
102
arranged axially of the motor, and each of the stators
102
has two stator yokes
106
disposed so as to be axially opposed to each other. In each stator
102
, a stator coil
105
is concentrically wound on a bobbin
101
held by the two stator yokes
106
. Each bobbin
101
having the stator coil
105
wound thereon is axially sandwiched and fixed by and between the two stator yokes
106
. Each of the stator yokes
106
,
106
is formed with stator teeth
106
a
and
106
b
alternately disposed circumferentially of the inner diametral surface of the bobbin
101
. On the other hand, the pair of stator yokes
106
and
106
having the stator teeth
106
a
and
106
b
are fixed to the case
103
of each stator
102
. Thus, the stators
102
are constructed.
A flange
115
and a bearing
108
are fixed to one (the left one as viewed in
FIG. 24
) of the two sets of case
103
, and a bearing
108
on the opposite side is fixed to the other (the right one as viewed in
FIG. 24
) case
103
. A rotor
109
is of such a structure that a rotor magnet
111
is fixed to a rotor shaft
110
. An air gap is formed between the outer peripheral surface of the rotor magnet
111
and the inner diametral surface of the stator yoke
106
of the stator
102
. The rotor shaft
110
is rotatably supported by the two bearings
108
fixed to each case
103
.
FIG. 26
of the accompanying drawings is a plan view exemplifying a step motor driven by a coil which is used in a timepiece or the like. In
FIG. 26
, reference numeral
201
designates a rotor comprising a permanent magnet, reference numerals
202
and
203
denote stators, and reference numeral
204
designates a coil.
However, in the prior art compact step motor shown in
FIG. 24
, the case
103
, the bobbin
101
, the stator coil
105
and the stator yoke
106
are concentrically disposed around the rotor, and this leads to the inconvenience that the outside dimension of the motor becomes large. Also, a magnetic flux created by the electrical energization of the stator coils
105
passes chiefly through the end surface
106
a
1
of the stator tooth
106
a
and the end surface
106
b
1
of the stator tooth
106
b
, as shown in
FIG. 25
of the accompanying drawings and therefore does not effectively act on the rotor magnet
111
, and there is the problem left to be solved that the output of the motor does not become high. Also, in the motor shown in
FIG. 26
, there is the problem left to be solved that a magnetic flux created by the electrical energization of the coil
204
concentrates in the portion of a small gap between the rotor
201
and the stator
202
and does not effectively act on the magnet
201
.
The applicant of the basic application in Japan has proposed as U.S. Pat. No. 5,831,356 a motor which has solved such problems.
This proposed motor is designed such that a rotor comprising a permanent magnet circumferentially equidistantly divided and alternately magnetized to different poles is formed into a cylindrical shape, a first coil, the rotor and a second coil are disposed axially of the rotor in the named order, a first outer magnetic pole and a first inner magnetic pole excited by the first coil are opposed to the outer peripheral surface and inner peripheral surface, respectively, of the rotor, and a second outer magnetic pole and a second inner magnetic pole excited by the second coil are opposed to the outer peripheral surface and inner peripheral surface, respectively, of the rotor, and a rotary shaft, which is a rotor shaft, is taken out of the cylindrically shaped permanent magnet.
The motor of such a construction is high in output and can have its outside dimension made small, but the working of its magnetic pole teeth is difficult because the diametral dimension of its inner magnetic poles is small, and it has been desired that a stable output free of fluctuation be obtained from a motor of a small diametral dimension.
Therefore, the applicant of the basic application filed in Japan has recently proposed a motor in which the shape of inner magnetic poles is made readily workable as U.S. patent application Ser. No. 08/994,994, and a rotor, in which output transmitting means, such as gears and pulleys, are easily mounted on a rotary shaft of small diametral dimension to thereby obtain a stable output free of fluctuation, has been proposed as U.S. patent application Ser. No. 09/022,474.
Recently, it has been desired that a motor having a high output and which can be constructed super-compactly be obtained.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-noted circumstances and an object thereof is to provide a motor which is high in output and is constructed more super-compactly.
Another object of the present invention is to stabilize the positioning of a rotor when a motor is made into a one-phase motor.
Further objects of the present invention will become apparent from the following description of some specific embodiments of the invention.


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U.S. application No. 08/994,994, filed Dec. 19, 1997.
U.S. application No. 09/022,474, filed Feb. 12, 1998.

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