Dynamic magnetic information storage or retrieval – Head mounting – For shifting head between tracks
Reexamination Certificate
2001-12-04
2004-04-20
Heinz, A. J. (Department: 2653)
Dynamic magnetic information storage or retrieval
Head mounting
For shifting head between tracks
Reexamination Certificate
active
06724578
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an actuator which is used for transferring a head of a magnetic disk drive and the like.
BACKGROUND ART
Hereinafter, a conventional actuator will be described with reference to
FIGS. 7
to
10
.
FIGS. 7
to
10
are diagrams for illustrating structures of a conventional actuator.
FIG. 7
is a sectional view illustrating the actuator.
FIG. 8
is a perspective view illustrating a moving part of the actuator.
FIG. 9
is a sectional view illustrating a metallic mold for forming the moving part of the actuator. And,
FIG. 10
is an enlarged view illustrating a terminal section of FIG.
9
.
In
FIG. 7
, numerals
21
a
and
21
b
denote opposite yokes which are provided with a predetermined space therebetween; numeral
22
denotes a coil which is movably wound between the yokes
21
a
and
21
b;
and numeral
23
denotes a permanent magnet which is attached between the yokes
21
a
and
21
b,
and to at least one of the yokes, and applies a magnetic field to the coil
22
. The permanent magnet
23
is attached to the yoke
21
a
in the example shown in
FIG. 7
, magnetized as shown in this figure, and applies a magnetic flux to the coil
22
.
In
FIG. 8
, numeral
22
denotes the coil which is movably wound between the yokes
21
a
and
21
b,
and numeral
25
denotes a holding member made of a thermoplastic resin, which holds the coil
22
. Numeral
26
denotes a housing made of metal material such as aluminum alloy and the like. A rotation constraint mechanism can be fitted in a hole
27
provided in the housing
26
, and a magnetic head can be fitted in a hole
28
(the rotation constraint mechanism and the magnetic head are not shown in this figure). Numerals
29
a
and
29
b
denote terminals to which both end parts of a strand of the coil
22
are electrically connected. Usually, the terminals
29
a
and
29
b
are inexpensive, so pin-shaped ones made of conductive material are employed. Numeral
30
denotes a flexible circuit board including a conductor part which transmits a current from a current generation source (not shown) to the coil
22
via the pin-shaped terminals
29
a
and
29
b.
In
FIG. 8
, the coil
22
is wound in a shape of a trapezoid, and when a current in a clockwise direction is passed through the coil
22
, a force is generated in the coil
22
in accordance with Fleming's left hand rule, and the coil
22
moves in a direction of arrow
24
. In this case, in
FIG. 7
, in a part on a right side of the coil
22
, a current flows from a far side to a near side, and in a part on a left side of the coil
22
, the current flows from a near side to a far side. When a current in a counterclockwise direction is passed through the coil
22
, the coil
22
moves in an opposite direction to that of arrow
24
. In this case, in
FIG. 7
, in a part on the right side of the coil
22
, a current flows from a near side to a far side, and in a part on the left side of the coil
22
, a current flows from a far side to a near side. Here, the coil
22
is set by a stopper (not shown) to move only within a coil movable range.
Next, a production method of the conventional movable part will be described with reference to
FIGS. 8 and 9
.
In
FIG. 9
, numerals
31
a
and
31
b
denote metallic molds and, for convenience sake, the metallic mold
31
b
is described as an upper part, but the mold
31
b
is a lower mold and the mold
31
a
is an upper mold. Numeral
32
denotes a direction of separation between the metallic molds
31
a
and
31
b.
Initially, coil
22
, pin-shaped terminals
29
a
and
29
b
(not shown in
FIG. 9
) to which the coil
22
is connected, and housing
26
are positioned in the metallic molds
31
a
and
31
b,
and thermoplastic resin is injected into the metallic molds
31
a
and
31
b,
thereby forming holding member
25
, and integrating the coil
22
, the housing
26
, and the pin-shaped terminals
29
a
and
29
b.
In
FIG. 9
, in the metallic molds
31
a
and
31
b,
a longitudinal direction of the pin-shaped terminals
29
a
and
29
b
is directed in the same direction as the separation direction
32
.
Next, flexible circuit board
30
is fixed on the housing
26
by a fastening device such as a screw (not shown). At this time, parts of the pin-shaped terminals
29
a
and
29
b,
exposed from the holding member
25
, are inserted into holes
30
a
and
30
b
provided in a conductor end part of the flexible circuit board
30
, and projecting parts of the pin-shaped terminals
29
a
and
29
b
and the conductor part are connected electrically with solder.
Next, a structure of a pin-shaped terminal section in the conventional movable part will be described with reference to FIG.
10
.
In this figure, one end of the pin-shaped terminal
29
a
is held by the holding member
25
, and another end is exposed from the holding member
25
. Coil strand
22
c
is wound on a part of the pin-shaped terminals
29
a,
which is buried in the holding member
25
, and electrically connected thereto with solder
33
a.
Further, in a state where the exposed part of the pin-shaped terminal
29
a
is inserted into the hole
30
a
provided in the flexible circuit board
30
, the exposed part and the conductor part
30
c
of the flexible circuit board
30
are electrically connected with solder
33
b.
In addition, the pin-shaped terminal
29
b
is similarly connected to the coil
22
and the flexible circuit board
30
.
According to the above-mentioned construction, the coil is of a flat type and therefore the separation direction
32
is set to be perpendicular to a coil moving direction, for convenience during production in the metallic molds. In addition, it is difficult to arrange a longitudinal direction of the pin-shaped terminals parallel with the coil moving direction, for convenience during production in the metallic molds, and therefore the longitudinal direction of the pin-shaped terminal is directed in the same direction as the separating direction
32
.
Therefore, in order to ensure a length of the pin-shaped terminals, which is required for positioning in the metallic mold, a prescribed length is required. Further, because the pin-shaped terminals exposed from the holding member are inserted into the holes in the conductor end part of the flexible circuit board and electrically connected by solder, the exposed parts of the pin-shaped terminals cannot be shortened. In addition, the part of the pin-shaped terminal, which is buried in the holding member, cannot be shortened because the part is wound by the coil strand and electrically connected thereto with the solder.
The longitudinal direction of the pin-shaped terminal formed as described above corresponds to a thickness direction of an apparatus into which the actuator is installed, and in such construction, while thinner apparatus are demanded in recent years, it is very difficult to provide these thinner apparatus.
In addition, as described above, in a state where pin-shaped terminals are inserted into the holes provided in the flexible circuit board, the pin-shaped terminals are covered and connected by solder, and therefore pin-shaped terminal connecting parts on the flexible circuit board become larger. As a result, adjacent permanent magnets or yokes become smaller, which prevents an actuator in its entirety from generating a large torque.
Further, since two pin-shaped terminals have the same shape, when these terminals are positioned in metallic molds, they may be erroneously placed. Accordingly, a direction of current which passes through the coil becomes opposite to a proper direction, which causes a malfunction in that the movable part of the actuator moves in an opposite direction.
The present invention is made to solve the above-described problems, and has for its object to provide an actuator which can thin an apparatus into which the actuator is installed and prevent resultant malfunction.
SUMMARY OF INVENTION
The present invention is made to achieve the above-mentioned object, and in accordance with a first aspect of the invention an
Heinz A. J.
Matsushita Electric - Industrial Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Electrical connection for the actuator coil of a magnetic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electrical connection for the actuator coil of a magnetic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrical connection for the actuator coil of a magnetic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3266834