Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-05-23
2004-03-02
Dougherty, Thomas M. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S089000, C310S049030
Reexamination Certificate
active
06700261
ABSTRACT:
BACKGROUND OF THE INVENTION
1) Field of the Invention
The present invention relates to improvements on motors, and more particularly to improvements on stator casings of motors.
2) Related Art
FIG. 4
shows a conventional stepping motor. The stepping motor has a stator
51
that is formed from a coil bobbin
61
and a coil bobbin
62
disposed adjacent to one another in the axial direction. A coil
61
a
is wound around the coil bobbin
61
and a coil
62
a
is wound around the coil bobbin
62
. An inner yoke
55
equipped with pole teeth
55
a
and an inner yoke
56
equipped with pole teeth
56
a
are disposed adjacent to one another between the coil bobbins
61
and
62
. An outer yoke
57
equipped with pole teeth
57
a
and an outer yoke
58
equipped with pole teeth
58
a
are disposed outside in the axial direction of the coil bobbins
61
and
62
. The outer yoke
57
is formed in a manner to cover the exterior side of the coil
61
a
, and the outer yoke
58
is formed in a manner to cover the exterior side of the coil
62
a
, such that the outer yokes
57
and
58
respectively serve as an exterior casing of the motor. A rotor
52
having a rotor shaft
53
is disposed within an internal peripheral surface of the stator
51
opposite to the pole teeth
55
a
-
58
a
. A cap
54
is attached to one end face of the stator
51
. A bearing
54
a
is disposed in the cap
54
such that the bearing
54
a
supports one end of the rotor shaft
53
.
FIG. 5
shows an exterior view of the stepping motor. Opening sections
57
b
and
58
b
are provided in the external yokes
57
and
58
that serve as the motor casing, respectively. The terminal section
63
protrudes from a window section that is formed by the opening sections
57
b
and
58
b
. The terminal section
63
has terminal pins
63
a
,
63
c
,
63
b
and
63
d
fixedly provided at equal intervals thereon. The terminal pin
63
a
is connected to a winding start section of the winding
61
a
, the terminal pin
63
c
is connected to a winding end section of the winding
61
a
, the terminal pin
63
b
is connected to a winding start section of the winding
62
a
and the terminal pin
63
d
is connected to a winding end section of the winding
62
a.
The motor thus constructed in a manner described above has a structure in which, as shown in
FIG. 6
, one end of the rotor shaft is supported by a frame. A channel shaped frame
65
is affixed to a stator
51
.
As described above, one end of the rotor shaft
53
of the rotor
52
is supported by a bearing that is formed in the cap
54
on one side of the stator
51
, and the other end of the rotor shaft
53
passes through the stator
51
and protrudes to a great extent on the other side. In other words, the rotor shaft
53
of the rotor
52
passes through a passing aperture
71
a
that is formed in a plane section
71
of the frame
65
that is affixed to the stator
51
, and one end of the rotor shaft
53
is supported on a bearing
73
that is mounted on a plane section
72
of the frame
65
that opposes to the plane section
71
. An external peripheral surface of a section of the rotary shaft
53
that protrudes on the side of the frame
65
defines a lead screw section
67
.
The motor having the structure described above is assembled in the following manner. First, the frame
65
is affixed to one end surface of the stator
51
. Then, as shown in
FIG. 7
, one end of the rotor shaft
53
of the rotor
52
is inserted in the stator
51
on the side where the frame
65
is not mounted (in a direction indicated by the arrow in FIG.
7
). When the end of the rotor shaft
53
passes the internal surface of the stator
51
and the passing aperture
71
a
of the frame
65
and reaches the bearing
73
(see
FIG. 6
) that is mounted on the frame
65
, the cap
54
is attached to the stator
51
. In this manner, the motor is assembled.
In the motor having the structure described above, an exterior casing that encloses the exterior of the stator
51
is formed from external peripheral sections of the external yoke
57
equipped with the pole teeth
57
a
and the external yoke
58
equipped with the pole teeth
58
a
. The external casing has a relatively complex configuration, and is composed of two members that are divided up and down in the axial direction. In addition, connecting sections between the external yokes
57
and
58
are provided with the opening sections
57
b
and
58
b
, respectively. Therefore, when the external yokes
57
and
58
are disposed adjacent to each other in the axial direction, the opening sections
57
b
and
58
b
need to be carefully aligned with each other. Accordingly, a mold for making the external casing has a complex configuration, and the assembly efficiency is poor.
Also, in the above-described motor, when one end of the rotor shaft
53
of the rotor
52
is passed through the internal empty space within the stator
51
and protruded on the side of the frame
65
, and is supported by the bearing
73
that is mounted on the frame
65
, there is a risk that the lead screw section
67
collides with an internal surface of the passing aperture
71
a
that is formed in the plane section
71
of the frame
65
. In other words, when the works described above are performed, the rotor shaft
53
needs to be maintained perpendicular to the plane section
71
, and the center of the rotor shaft
53
needs to coincide with the center of the passing aperture
71
a
. These tasks are very difficult. Moreover, there is only a small difference between the diameter of the passing aperture
71
a
formed in the plane section
71
that serves as an affixing surface of the frame
65
to be affixed to the stator
51
and an external diameter of the lead screw
67
. In addition, since the passing aperture
71
a
is punched out by a press machine, edges of the aperture may have burrs. Therefore, unless the works are carefully conducted, the rotor shaft
53
could be inserted with its center being eccentric with respect to the passing aperture
71
a
, as shown in FIG.
7
. As a result, the lead screw section
67
may come in contact with the internal surface of the passing aperture
71
a
and scrape the burrs, which may clog the male screw of the lead screw
67
or damage the male screw of the lead screw section
67
. As a result, when the male screw of the lead screw section
67
is damaged, noise may be generated due to the damage in the lead screw section
67
when the motor is driven. When the male screw of the lead screw section
67
is clogged with burrs, noise may likewise be generated or the motor may become inoperable during its operation.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a motor that can be readily manufactured and readily assembled with respect to a stator of the motor by simplifying the structure of an exterior casing of the motor.
It is another object of the present invention to provide a motor that can prevent damages on a lead screw section of a rotary shaft when the rotor is assembled, and also prevent generation of metal powder from burrs at a passing aperture of a frame or the lead screw section that may be scraped when the rotor is assembled.
In accordance with an embodiment of the present invention, a motor has a stator including a coil bobbin with winding sections to be wound by windings and a terminal section that outwardly protrudes in a radial direction of the coil bobbin and has fixed protruded terminal pins that are to be connected to winding start sections and wiring end sections of the windings. In one aspect of the embodiment of the present invention, a curled case covers an exterior of the windings of the stator. The curled case may preferably be formed by curling a flat metal plate along a peripheral direction of the stator. The curled case has end sections in the peripheral direction and an opening section defined by the end sections of the curled case. The terminal section protrudes through the opening section, and the opening section may preferably open at an opening arc angle defined by l
Dougherty Thomas M.
Elkassabgi H. Y.
Hogan & Hartson LLP
Sankyo Seiki Mfg. Co. Ltd.
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