Motor

Details Motor Motor

1999-11-30

2002-10-15

Mullins, Burton S. (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S06700R, C310S257000, C310S261100, C310S266000, C310S156020, C310S179000

Reexamination Certificate

active

06465916

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a super-compact motor suitable for arrival or destination informing apparatus in a portable telephone, for example.
2. Related Background Art
Among communication apparatuses for portable equipments, an alarming device for informing the user of communication by vibration is already known. In such a pager motor, a weight having an imbalanced mass is attached to an output shaft of the motor so that vibration is generated when the motor is rotatingly driven. Such motors will be widely used in the future. It is desirable that such a motor be made more compact as the portable equipment becomes small-sized.
In the past, as a type suitable for a compact motor, a brushless type is known. Among the motors of brushless type, there are the following stepping motors having a simple circuit.
A compact cylindrical stepping motor as shown in
FIG. 19
is known. Stator coils
105
are concentrically wound around corresponding bobbins
101
. The bobbins
101
are pinched and secured between corresponding stator yokes
106
from an axial direction, and the stator yokes
106
have stator teeth
106
a
and stator teeth
106
b
arranged alternately along a circumferential direction of inner surfaces of the bobbins
101
. The stator yokes
106
, integral with the stator teeth
106
a
or
106
b
, are secured to cases
103
to constitute a stator
102
.
A flange
115
and a bearing
108
are secured to one of a set of cases
103
, and another bearing
108
is secured to the other case
103
. A rotor
109
comprises a rotor magnet
111
secured to a rotor shaft
110
, and radial gaps are defined between the rotor magnet
111
and the stator yokes
106
of the stator
102
. The rotor shaft
110
is rotatably supported by the bearings
108
.
Further, a stepping motor driven by a single coil and widely used with a clock as shown in
FIG. 21
is also known. A rotor
201
comprises a permanent magnet and is associated with a stator
203
and a coil
204
.
However, in the conventional compact stepping motor shown in
FIG. 19
, since the cases
103
, bobbins
101
, stator coils
105
and stator yokes
106
are concentrically arranged around the rotor, the entire dimension of the motor becomes great. Further, as shown in
FIG. 20
, since magnetic flux generated by energization of the stator coil
105
mainly passes through an end face
106
a
1
of the stator tooth
106
a
and an end face
106
b
1
of the stator tooth
106
b
, the magnetic flux does not act on the rotor magnet
111
effectively, with the result that a high output of the motor cannot be obtained.
Also regarding the motor shown in
FIG. 21
, magnetic flux generated by energization of the coil is concentrated into the smallest gap between the stator
203
and the coil
204
and does not act on the magnet effectively.
In a pager motor in which the weight having an mass imbalanced with respect to a rotational center is attached to the output shaft of the motor to convert rotation of the motor into vibration, since the weight is attached on an outer surface of the motor body, the assembling must be effected very carefully so that lead wires, a flexible print substrate, and the like are not positioned in a rotation path of the weight.
A destination informing device of the wrist-watch type has also been proposed, as disclosed in Japanese Patent Laid-Open No. 8-146161 (1996).
In this case, since a weight is secured to an output shaft protruded outwardly from a motor, the entire motor including the weight must be covered by a case, which makes compactness of the destination informing device difficult to achieve. Further, when the user wears the communication device on a portion of his body where vibration can easily be detected, the presence of such a device is not preferable from the viewpoint of fashion. An example is shown in FIG.
22
. In
FIG. 22
, the reference numeral
300
denotes a motor;
301
denotes a weight;
302
,
303
denote cases of the destination informing device; and
304
denotes a motor attaching member for attaching the motor
300
to the case
303
. Since the weight
301
is associated with the cases
302
,
303
via the motor
300
and the motor attaching member
304
, in
FIG. 22
, great gaps a, b must be maintained between the weight
301
and the cases
302
,
303
. Thus, the thickness t of the destination informing device is increased.
In communication device of the wrist-watch type, if the user has already worn his wrist watch on his wrist, the fact that both the wrist watch and the communication device are worn on his wrist is not preferable from the viewpoint of fashion. Further, although it is considered that a communication device is incorporated into a wrist watch itself, since the design, the size, and the color of the watch are limited, it is not preferable from the viewpoint of fashion.
As a compact motor for a communication apparatus, a cored AC motor or coreless AC motor of brush type can be used. However, since such a motor has a relatively large number of constructural parts, if the motor is made super-compact, it becomes difficult to manufacture and assemble such constructural parts, which leads to an increase in cost.
The inventors have proposed a motor solving the disadvantage of the conventional motor shown in
FIG. 19
, as disclosed in U.S. Pat. No. 5,831,356.
In this proposed motor, a cylindrical rotor comprises permanent magnets equidistantly disposed in a circumferential direction and having alternate magnetic poles; a first coil, a rotor and a second coil are sequentially disposed in an axial direction of the rotor; a first outer magnetic pole and a first inner magnetic pole which are excited by the first coil an are opposed to outer and inner peripheral surfaces of the rotor, and a second outer magnetic pole and a second inner magnetic pole, which are excited by the second coil are opposed to the outer and inner peripheral surfaces of the rotor; and a rotary shaft (rotor shaft) extends from the interior of the cylindrically arranged permanent magnets.
Although such a motor can have a high output and a small outer dimension, since the diametrical dimensions of the inner magnetic poles are small, it is difficult to manufacture magnetic teeth. Further, it has been requested that a stable output having no vibration be obtained from a motor having a small diametrical dimension.
To this end, the inventors have recently proposed a motor in which inner magnetic poles have configuration having good workability, as described in U.S. patent application Ser. No. 08/994,994, and the inventors have also proposed a rotor in which output transmitting means, such as a gear or a pulley, can easily be attached to a rotary shaft having a small diametrical dimension and a stable output having no vibration can be obtained, as described in U.S. patent application Ser. No. 09/022,474.
Recently, it has been requested to provide a motor having a high output and super-compact size.
To this end, the inventors have recently proposed a motor constructed as a single phase motor to achieve high output and super-compact size, as described in U.S. patent application Ser. No. 09/293,063.
In recent years, it has been requested that such a motor having a high output and super-compact size be applied to a destination informing apparatus.
SUMMARY OF THE INVENTION
The present invention aims to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide a motor having a configuration suitable for a communication apparatus, in which a high output can be obtained with a simple construction.
Another object of the present invention is to provide a motor for a communication apparatus, in which the motor is constructed as a single phase motor to stabilize initial positioning of a rotor.
The other objects and features of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawing

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