Inductor devices – With outer casing or housing
Reexamination Certificate
2003-07-28
2004-11-16
Mai, Anh (Department: 2832)
Inductor devices
With outer casing or housing
C336S096000, C336S198000
Reexamination Certificate
active
06819212
ABSTRACT:
This application is based on Application No. 2000-327225, filed in Japan on Oct. 26, 2000, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electromagnetic device such as a stepping motor, a solenoid valve, or the like, used in an automotive continuously variable transmission, for example.
2. Description of the Related Art
FIG. 6
is an external view of a permanent-magnet stepping motor,
FIG. 7
is a cross section taken along line VII—VII in
FIG. 6
,
FIG. 8
is a cross section taken along line VIII—VIII in
FIG. 7
,
FIG. 9
is a cross section taken along line IX—IX in
FIG. 7
, and
FIG. 10
is a partial exploded perspective of the stepping motor in FIG.
7
.
In the figures, a permanent-magnet (PM) stepping motor
1
, which is immersed and used in an oil, includes: an outer casing
2
made of a resin; a tubular housing
12
made of a resin which is linked to the outer casing
2
; a motor main body
3
disposed inside the outer casing
2
; a shaft
4
functioning as a moveable shaft rotated by the motor main body
3
; and a conversion mechanism
31
for converting rotation of the shaft
4
into rectilinear motion. Moreover, the outer casing
2
and the housing
12
constitute a cover.
The motor main body
3
includes a stator
5
secured to the outer casing
2
, and a rotor
6
secured to the shaft
4
. The stator
5
has: coils
7
each constructed by winding a conducting wire in which an electrically-insulating layer is formed on a copper wire surface; coil terminals
8
led out from the coils
7
; connector terminals
9
connected to the coil terminals
8
; and an outside connector
25
connected to the connector terminals
9
. The rotor
6
has a bush
10
secured to the shaft
4
, and a circumferentially-magnetized hollow cylindrical permanent magnet
11
fitted over and secured to the bush
10
.
The housing
12
is fastened to the outer casing
2
by a plurality of screws
12
A extending parallel to the shaft
4
. A circular interfitting aperture
2
a
is formed in the outer casing
2
, and an interfitting portion
12
a
for inserting into the interfitting aperture
2
a
is formed on the housing
12
. As shown in
FIG. 8
, three positioning projections
12
b
, which protrude radially and come into contact with an inner circumferential surface of the interfitting aperture
2
a
, are formed on an outer circumferential surface of the interfitting portion
12
a
. Furthermore, an annular groove
12
c
is formed in a joining surface of the housing
12
, where the housing
12
joins the outer casing
2
.
A housing communicating aperture
12
d
communicating between internal and external portions of the housing
12
is disposed in a side surface portion of the housing
12
. A filter
13
for catching contaminants contained in the oil is disposed in the housing communicating aperture
12
d
. The shaft
4
is rotatably held by a casing bearing
14
and a housing bearing
15
. The housing bearing
15
, which is secured inside the housing
12
, is a rubber-seal type.
A rod
16
reciprocated in an axial direction of the shaft
4
by rotation of the shaft
4
is disposed at a tip portion of the housing
12
. A base-end portion of the rod
16
is inserted inside the housing
12
, and a tip portion of the rod
16
protrudes from the tip portion of the housing
12
. A rod communicating aperture
16
a
communicating between the internal portion of the housing
12
and an internal portion of the rod
16
is formed in the rod
16
. A sleeve
17
for guiding rectilinear motion of the rod
16
, an oil seal
18
for preventing penetration of contaminants from an outer circumferential portion of the rod
16
, and a ring-shaped stopper
19
for regulating progression of the rod
16
are each secured to an inner circumferential surface of the tip portion of the housing
12
.
The conversion mechanism
31
includes a thread portion
4
a
, a guide member
20
made of a resin which is formed in the base-end portion of the rod
16
and is engaged with the thread portion
4
a
, and a stopper
21
made of a metal which is secured to the shaft
4
and regulates regression of the rod
16
. Stopper surfaces
20
b
and
21
a
which are perpendicular to the direction of rotation of the shaft
4
are formed on the guide member
20
and the stopper
21
, respectively. As shown in
FIG. 9
, a rotation-regulating projection portion
20
a
which protrudes radially and regulates rotation of the rod
16
is formed on an outer circumferential portion of the guide member
20
. Consequently, the guide member
20
is displaced in an axial direction of the shaft
4
by rotation of the shaft
4
. An operating member
22
made of a resin is mounted to the tip portion of the rod
16
.
A construction of the stator
5
will now be explained in detail with reference to
FIGS. 11
to
16
.
As shown in
FIG. 11
, conducting wires
50
constituting the coils
7
are each formed by coating an electrically-insulating layer
52
onto a copper wire
51
. As shown in
FIG. 12
, the coils
7
are each constructed by winding the conducting wires
50
for a predetermined number of winds into a bifilar winding (parallel winding) on a conducting-wire spool portion
53
a
of first and second bobbins
53
A and
53
B. In other words, the coils
7
are constructed by winding first and second conducting wires
50
A and
50
B onto each of the conducting-wire spool portions
53
a
together side by side in an annular shape. Then, as shown in
FIGS. 13 and 14
, first to third coil terminals
8
A,
8
B, and
8
C are mounted to each of the first and second bobbins
53
A and
53
B, the electrically-insulating layer
52
is removed from a winding start end of the first conducting wire
50
A and the winding start end of the first conducting wire
50
A is wound onto a tie-off portion
8
a
of the first coil terminal
8
A and soldered, the electrically-insulating layer
52
is removed from a winding finish end of the second conducting wire
50
B and the winding finish end of the second conducting wire
50
B is wound onto the tie-off portion
8
a
of the third coil terminal
8
C and soldered, and in addition, the electrically-insulating layer
52
is removed from a winding finish end of the conducting wire
50
A and a winding start end of the conducting wire
50
B and the winding finish end of the first conducting wire
50
A and the winding start end of the second conducting wire
50
B are both wound onto the tie-off portion
8
a
of the second coil terminal
8
B and soldered.
As shown in
FIG. 15
, the coils
7
wound onto the first and second bobbins
53
A and
53
B are embedded in an outer molding
54
. Here, each of the coil terminals
8
A,
8
B, and
8
C is folded and bent, and the tie-off portions
8
a
to which the end portions of the conducting wires
50
A and
50
B are soldered are also embedded in the outer molding
54
. In addition, as shown in
FIG. 16
, cores
55
made of iron are disposed so as to surround the coils
7
, completing the construction of the stator
5
.
In the stepping motor
1
constructed in this manner, as shown in
FIG. 17
, the coils
7
are constituted by first phase and second phase excitation coils
7
a
and
7
b
connected in series, and third phase and fourth phase excitation coils
7
c
and
7
d
connected in series. A connection portion M
1
connecting the first phase and the second phase excitation coils
7
a
and
7
b
, and a connection portion M
2
connecting the third phase and the fourth phase excitation coils
7
c
and
7
d
are grounded, a voltage of +14 V being applied between a terminal S
1
of the first phase excitation coil
7
a
and the connection portion M
1
, a voltage of −14 V being applied between the connection portion M
1
and the terminal S
2
of the second phase excitation coil
7
b
, a voltage of +14 V being applied between a terminal S
3
of the third phase excitation coil
7
c
and the connection portion M
2
, and a voltage of −14 V being applied between the connection
Hasegawa Shiro
Hashimoto Naoya
Miyaoku Teruo
Ohta Hirohisa
Ozawa Hiromasa
Mai Anh
Mitsubishi Denki & Kabushiki Kaisha
Sughrue & Mion, PLLC
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