Electrical generator or motor structure – Dynamoelectric – Linear
Reexamination Certificate
2002-08-21
2004-09-07
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Linear
C310S012060, C310S015000, C360S264700, C360S265800
Reexamination Certificate
active
06787941
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an actuator including a carriage having a head and rocking about a rotary shaft, in a disk unit such as, for example, a magnetic disk unit.
BACKGROUND ART
In a disk unit such as a magnetic disk unit, a carriage provided with a head is required to have excellent dynamic characteristics in order to get access to a target track accurately at a high speed.
FIG. 8
is an exploded perspective view of a conventional actuator for a disk unit or the like.
FIG. 9
is a plan view of the carriage of
FIG. 8
, and
FIG. 10
shows the X—X section of FIG.
9
.
In
FIG. 8
, magnets
15
are respectively fixed to upper and lower yokes
9
A,
9
B. The yokes
9
A,
9
B are secured by shafts
16
with a specified space there between in a manner such that magnets
15
are opposed to each other in reverse polarity. A coil
7
is fixed on one end of a carriage
8
, and on the other end is located a suspension
6
which supports a head
5
for signal recording and reproducing. The carriage
8
is supported by a rotary shaft (not shown) which is set through bearing
36
so that the coil
7
is positioned inside the space and able to rotate about the rotary shaft. That is, when the coil
7
is supplied with a current, a driving force is generated in the coil
7
according to the Fleming's rule, and thereby, the carriage
8
makes a rocking motion.
In a conventional actuator as described above, examples of configuration with the coil
7
fixed on the carriage
8
are shown in FIG.
9
and FIG.
10
. In these figures, projection
17
for securing the coil
7
is integrally disposed beforehand at the end of the carriage
8
, and the projection
17
and the coil
7
are secured by means of holding member
11
made up of thermoplastic resin.
However, in such conventional configuration, since the coil
7
is supported in a cantilever fashion by the carriage
8
, it is not possible to obtain sufficient strength and rigidity for the installation. As a result, the resonance frequency of the carriage
8
becomes lowered and it is unable to satisfy the requirement for higher performance of the disk unit.
FIG.
11
and
FIG. 12
are perspective views showing other examples of configuration with respect to the carriage
8
and the coil
7
.
FIG. 11
is a perspective view before assembly of the carriage
8
and the coil
7
.
FIG. 12
is a perspective view after assembly of the carriage
8
and the coil
7
. In
FIG. 12
, the portion shaded by black spots is the support member
11
made up of resin.
FIG. 13
shows the XIII—XIII section of FIG.
12
.
FIG. 14
shows the XIV—XIV section of FIG.
12
.
In
FIG. 11
, a long plate-form projection
13
is formed at the inside of coil fitting arm
12
A of the carriage
8
. Also, there are provided three through-holes
14
at the boundary between the bottom portion of projection
13
and the arm
12
A. The configuration of coil fitting arm
12
B is same as that of the coil fitting arm
12
A. The carriage
8
and the coil
7
are set in a metallic mold (not shown), and the coil
7
is positioned with reference to the carriage
8
, and holding member
11
made up of thermoplastic resin is filled therein. Thus, the coil
7
is fixed on the carriage
8
.
FIG. 12
is a perspective view of the coil
7
fixed on the carriage
8
. Like the XIII—XIII section of
FIG. 12
shown in
FIG. 13
, the through-holes
14
are filled with resin of the holding member
11
, and therefore, the coil
7
will be free from slipping off from the arms
12
A,
12
B in the direction of arrow X in FIG.
12
. Also, like the XIV—XIV section of
FIG. 12
shown in
FIG. 14
, the projection
13
bites into the holding member
11
, and the holding member
11
bites into the depression
7
A of winding of the coil
7
as well. Accordingly, the coil
7
is sufficiently held in the direction of arrow Y against the arms
12
A,
12
B. By such configuration, the portion of fitting the arms
12
A,
12
B and the coil
7
can be made nearly equal in thickness to the arms
12
A,
12
B. Since the coil
7
can be disposed between two strong arms
12
A and
12
B, the resonance frequency will become higher and it is possible to meet the requirement for higher performance of the disk unit.
However, with the recent improvement in performance of disk units, there is an increasing demand for smaller and thinner disk units. To make the disk unit further thinner, it is necessary to reduce the entire actuator less in thickness. For achieving the purpose, it is necessary to make the yokes
9
A,
9
B, and magnet
15
thinner, and also to reduce the thickness t see
FIG. 14
) of arms
12
A,
12
B and coil
7
as much as possible. However, if the thickness t of the arm
12
A shown in
FIG. 14
is reduced, it will become difficult to form the projection
13
in the center of arm
12
A.
DISCLOSURE OF THE INVENTION
The present invention is intended to solve the above problem, providing an actuator wherein the coil may be secured with a sufficient strength against the carriage even in case the coil fitting arm is reduced in thickness.
The actuator of the present invention has the following configuration.
In this configuration, there are provided a pair of yokes opposing to each other via the first specified space, a magnet fixed to at least one of the yokes, and a carriage holding a coil on one end thereof against the magnet via the second specified space and rocking about a rotary shaft; and the carriage comprises two coil fitting arms opposing to each other having stepped portions respectively formed on the opposing surfaces and at least one through-hole, piercing from the bottom to the top of the stepped portion, whose size is larger at the bottom than at the top thereof, the coil disposed between these two coil fitting arms, and a holding member for securing the coil fitting arms, the through-hole and the coil. The holding member is preferable to be formed of a resin-filled block.
By this configuration, since each of the coil fitting arms is provided with a stepped portion, the coil may be securely fixed on the arms even in case the arms are reduced in thickness. Also, there are provided through-holes at the stepped portion of the arm, and the through-hole area is larger at the bottom of the stepped portion than at the top thereof. Also, resin is filled into these through-holes to secure the coil, and the resin will free from slipping off from the holes, and thereby, the coil can be completely fixed on both arms.
REFERENCES:
patent: 5122703 (1992-06-01), Takahashi et al.
patent: 5168185 (1992-12-01), Umehara et al.
patent: 5600516 (1997-02-01), Phillips et al.
patent: 5621590 (1997-04-01), Pace et al.
patent: 5734528 (1998-03-01), Jabbari et al.
patent: 6310749 (2001-10-01), Beatty et al.
patent: 6507459 (2003-01-01), Kamigama
patent: 268513 (2000-09-01), None
Comas Yahveh
Rossi & Associates
Tamai Karl
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