Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Electrodynamically actuated
Reexamination Certificate
1999-12-28
2002-03-05
Barrera, Ramon M. (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Electrodynamically actuated
C335S148000, C335S223000, C218S141000
Reexamination Certificate
active
06353376
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a switching assembly for performing an electrode switching operation by means of electromagnetic actuation.
2. Description of the Related Art
FIG. 24
is a general block diagram of a switching assembly which is a first conventional example employing electromagnetic repulsion such as that disclosed in “Shingata Kousoku Suitchi no Kaihei Dousa Tokusei (Switching Operation Characteristics of New High-Speed Switches)”, Heisei 8-Nen Denki Gakkai Sangyou Ouyou Bumon Zenkoku Taikai Kouen Bangou 260 (Lecture No. 260, 1996 Institute of Electrical Engineers Industrial Applications Division All-Japan Conference), for example.
FIG. 24A
shows the closed state, and
FIG. 24B
shows the open state.
This switching assembly includes:
a switch portion
1
including a contactable fixed electrode
6
and a movable electrode
5
;
a repulsion plate
2
secured to a central portion of a movable shaft
4
connected to the movable electrode
5
;
an opening coil
3
a
for inducing current in the repulsion plate
2
, the opening coil
3
a
being disposed on the same side of the repulsion plate
2
as the movable electrode
5
in an axial direction; and
a closing coil
3
b
for inducing current in the repulsion plate, the closing coil
3
b
being disposed on the opposite side of the repulsion plate
2
from the opening coil
3
a.
The opening coil
3
a
and the closing coil
3
b
are connected to a magnetic field-generating current source (not shown).
Terminals
7
connecting to a circuit are connected to the movable electrode
5
and the fixed electrode
6
. Contact pressure input springs
8
a
and
8
b
for providing contact pressure between the movable electrode
5
and the fixed electrode
6
when the electrodes are closed, and an auxiliary circuit
9
working together with the opening and closing of the switch portion
1
, are disposed at the opposite end of the movable shaft
4
from the movable electrode
5
.
FIG. 25
is a graph showing the load characteristics of the contact pressure input springs
8
a
and
8
b
and their combined loads. In the graph,
40
are the load characteristics of the contact pressure input spring
8
a,
41
are the load characteristics of the contact pressure input spring
8
b,
and
42
are the combined loads of the contact pressure input springs
8
a
and
8
b.
The contact pressure input springs
8
a
and
8
b
are each disposed such that a load arises in a closing direction when the combined load is in a region of deflection from the central position to the closed position, and a load is provided in an opening direction when the combined load is in a region of deflection from the central position to the open position.
Next, the opening operation of a switching device of the above construction will be explained.
In the closed state shown in
FIG. 24A
, a magnetic field is generated when a pulsed current is passed through the opening coil
3
a.
A current is thus induced in the repulsion plate
2
such that a magnetic field is generated in a direction which cancels the magnetic field generated by the opening coil
3
a.
By interaction between the magnetic field generated by the opening coil
3
a
and the magnetic field generated by the repulsion plate
2
, the repulsion plate
2
is subjected to electromagnetic repulsion relative to the coil
3
a.
The movable shaft
4
and the movable electrode
5
, which are secured to the repulsion plate, are moved in the direction of repulsion by this electromagnetic repulsion. Then, as shown in
FIG. 25
, as the amount of deflection of the contact pressure input springs
8
a
and
8
b
changes from the closed position to the central position, the load characteristics
42
decrease, and when the central position is exceeded, the load characteristics become load in the opening direction, and when the amount of deflection of the contact pressure input springs
8
a
and
8
b
reaches the open position, the switch
1
is held in the open state shown in FIG.
24
B.
Next, the closing operation of the switching device will be explained.
In the open state shown in
FIG. 24B
, a magnetic field is generated when a pulsed current is passed through the closing coil
3
b.
A current is thus induced in the repulsion plate
2
, and the repulsion plate
2
is subjected to electromagnetic repulsion relative to the closing coil
3
b.
The movable shaft
4
and the movable electrode
5
, which are secured to the repulsion plate, are moved in the direction of repulsion by this electromagnetic repulsion. Then, as shown in
FIG. 25
, as the amount of deflection of the contact pressure input springs
8
a
and
8
b
changes from the open position to the central position, the load characteristics
42
increase, and when the central position is exceeded, the load characteristics become load in the closing direction, and when the amount of deflection of the contact pressure input springs
8
a
and
8
b
reaches the closed position, the switch
1
is in the closed state shown in FIG.
24
A.
FIG. 26
shows the slit construction of a plunger-type electromagnet which is part of a switching device which is a second conventional example such as that disclosed in Japanese Utility Model No. SHO 58-103114, for example.
In the drawing, a movable body
101
composed of magnetic material is secured to a tip portion of a movable shaft
100
. A blade spring
106
is secured to one side of the movable body
101
. A fixed body
102
composed of magnetic material opposes the movable body
101
across an air gap portion
104
. A coil
103
surrounded by an iron core
105
is disposed around a circumference of the fixed body
102
.
FIG. 27
is a perspective of the fixed body
102
in
FIG. 26
, and
FIG. 28
shows cross-sections of structural elements of the fixed body
102
.
The fixed body
102
includes a first cylinder portion
107
, a second cylinder portion
108
, and a third cylinder portion
109
each formed with a slit
110
and laminated.
Next, the operation of a switching assembly of the above construction will be explained.
A magnetic field is generated when an electric current is passed through the coil
103
, and this magnetic field forms a closed magnetic pathway crossing to the movable body
101
via the fixed body
102
and the air gap portion
104
and then returning to the fixed body
102
via the iron core
105
. At that time, magnetic attraction arises between the movable body
101
and the fixed body
102
due to interaction between the magnetic fields generated in each. The movable shaft
100
integrated with the movable body
101
is moved in opposition to the elastic force of the blade spring
106
by this magnetic attraction. Thus, a movable electrode (not shown) connected to a tip portion of the movable shaft
100
is separated from a fixed electrode (not shown), for example, opening the contacts of the switching assembly.
When the electric current in the coil
103
is interrupted, the fixed body
102
is demagnetized and the movable shaft
100
integrated with the movable body
101
is returned to its original position by the elastic force of the blade spring
106
, closing the contacts of the switching assembly.
In this switching assembly, when the magnetic field is generated, induced currents which generate electric fields in directions which obstruct the magnetic pathway arise in the movable body
101
, the fixed body
102
, and the iron core
105
. Eddy currents which arise in the movable body
101
and the fixed body
102
, in particular, obstruct swift generation of the above electromagnetic attraction, resulting in delays in the movement of the movable shaft
100
. In this example, swift establishment of electromagnetic force is ensured by using a laminated construction in the fixed body
102
comprising first to third cylinder portions
107
,
108
, and
109
and forming slits
110
therein in order to suppress eddy currents.
In the switching assembly of the first conventional example, because the magnetic field arising in the repulsion plate
2
due to
Akita Hiroyuki
Kishida Yukimori
Sasao Hiroyuki
Takeuchi Toshie
Yoshizawa Toshiyuki
Barrera Ramon M.
Leydig , Voit & Mayer, Ltd.
Mitsubishi Denki & Kabushiki Kaisha
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