Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2003-06-12
2004-10-19
Lam, Thanh (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S080000, C310S012060, C310S020000
Reexamination Certificate
active
06806597
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stepping motor structured by a rotor constituted by a permanent magnet and a stator around which an exciting coil is wound, and more particularly to a lead screw type stepping motor in which a rotation of the rotor is converted into a linear movement by a slider to output toward an outer portion.
2. Description of Conventional Art
A conventional lead screw type stepping motor is shown in
FIGS. 2 and 3
.
FIG. 2
is a vertical cross sectional side view, and
FIG. 3
is a vertical cross sectional side view in a line X—X in FIG.
2
. Reference numeral
10
denotes a stator around which an exciting coil
11
is wound. A rotor
13
provided with a permanent magnet
12
is arranged inside of the stator
10
. The rotor
12
is rotatably supported to the case
14
receiving the stator
10
, a left end of the stator
10
is rotatably supported to a first support member
15
by a first bearing
16
, and the right end of the stator
10
is rotatably supported to a second support member
17
by a second bearing
18
. Further, a female threaded hole
19
is pierced through in the center of the rotor
13
along the longitudinal direction A—A. Further, a rod-shaped slider
20
is engaged with the female threaded hole
19
of the rotor
13
, the right end of the slider
20
protrudes outward and a rotation of the slider
20
is inhibited by the following manner. An oval-shaped segmental circle portion
20
A is provided near the right end of the slider
20
, and this segmental circle portion
20
A is arranged to and guided by an oval-shaped segmental circle hole
21
B formed in a bottom portion
21
A of a cup member
21
which is fixedly arranged in the right end of the case
14
. The segmental circle portion
20
A and the segmental circle hole
21
A are disclosed in FIG.
3
.
In accordance with the structure mentioned above, when a pulse signal for control is input to the exciting coil
11
, the rotor
13
rotates one step angle by one step angle every one pulse input, and the rotor
13
rotates in correspondence to the input signal. Further, in accordance with the rotation of the rotor
13
, since the rotation of the slider
20
is inhibited by the segmental circle portion
20
A and the segmental circle hole
21
B, the slider
20
moves linearly in the axial direction of the slider
20
in correspondence to the rotation of the rotor
13
. On the other hand, a movement of the slider
20
to the right side in
FIG. 2
is regulated by a right end portion
22
A of a male screw
22
being brought into contact with the bottom portion
21
A of the cup member
21
.
In accordance with the conventional lead screw type stepping motor, since cross sectional shapes of the segmental circle portion
20
A formed in the slider
20
and the segmental circle hole
21
B formed in the cup member
21
are formed in an oval shape, it is hard to form a flat portion with an accurate symmetry level and an accurate shape precision, and there is a risk that non-reaction area is generated at a time when the rotor
13
rotates and reversely rotates. Particularly, in the case that this non-reaction area is great, there is a risk that a dicrepancy is generated between a number of pulse input to the stepping motor and a moving amount of the slider
20
. In accordance with the structure mentioned above, it is impossible to provide a lead screw type stepping motor having a high response and controllability with respect to the input signal applied to the motor. Further, in
FIG. 2
, the regulation of the rightward movement of the slider
20
is achieved by bringing the right end portion
22
A of the male screw
22
into contact with the bottom portion
21
A of the cup member
21
, however, in accordance with this structure, there is a risk that a regulated position is changed by a displacement of an assembled position at a time of assembling the cup member
21
in a right side plate
14
A of the case
14
, so that it is impossible to carry out an accurate initial alignment of the stepping motor.
SUMMARY OF THE INVENTION
The present invention is made by taking the problems mentioned above into consideration, and an object of the present invention is to provide a lead screw type stepping motor which is excellent in a response and a controllability with respect to an input signal applied to the motor, and can carry out an accurate initial alignment.
In accordance with the present invention, in order to achieve the object mentioned above, there is provided a lead screw type stepping motor structured such that a rotor is rotatably supported inside a stator around which an exciting coil is wound, a slider is arranged to be screwed with a female threaded hole provided through in a longitudinal direction of the rotor, and a rotation of the rotor is converted into a linear movement of the slider to be output, wherein a slit groove shaped in an oblong hole along the axial direction is pierced through in the slider, the slider is supported to a guide hole provided in a bearing portion of a case receiving the stator in such a manner as to freely move in the axial direction, a guide pin is arranged to be inserted into the slit groove, and both ends of the guide pin are press inserted and supported to the bearing portion.
When a pulse signal is input to the exciting coil and the rotor rotates, the slider which is inhibited by the slit groove and the guide pin from rotating, linearly moves in the axial direction of the slider. The slider rotation inhibiting means is achieved by the slit groove and the guide pin, and it is possible to maintain accuracy of manufacturing the slit groove and the guide pin, whereby it is possible to largely improve a response and a controllability of the slider with respect to the input signal applied to the motor. Further, since moving amount to one side and another side in the slider are regulated only by a length of the slit groove and the guide pin, it is particularly possible to accurately regulate the moving amount to one side and another side in the slider.
REFERENCES:
patent: 5085401 (1992-02-01), Botting et al.
patent: 5811901 (1998-09-01), Nagai et al.
patent: 6049151 (2000-04-01), Suzuki et al.
patent: 6603228 (2003-08-01), Sato
patent: 2002/0043880 (2002-04-01), Suzuki et al.
patent: 2002/0050751 (2002-05-01), Hashimoto et al.
patent: 2003/0052550 (2003-03-01), Hayashida et al.
Keihin Corporation
Lam Thanh
Rabin & Berdo P.C.
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