Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2003-11-21
2004-12-07
Le, Dang (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S216055, C310S012060
Reexamination Certificate
active
06828711
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a lamination for a linear motor and to an arrangement that provides a more secure mounting of said laminations.
BACKGROUND OF THE INVENTION
Linear motors are well known devices, in which one of a coil or magnet element is mounted to a fixed member, and the other element is mounted to a member to be moved. The linear motor has an array of inner laminations and an array of outer laminations, between which the magnet element is moved. Electric current is applied to the coil, which generates magnetic lines of force to interact with the magnet element to produce linear motion of the movable member. Such linear motors are generally used in refrigeration compressors in which the movable member is defined by the piston of the compressor and the magnet element is mounted to said piston. The coil is fixedly mounted to an external portion of the compressor structure that forms the cylinder, inside which the piston is reciprocated upon operation of the linear motor. Linear motors are used in other devices in order to, for example, reciprocate a shaft inside a bushing, with the movement of the shaft performing work in a machine.
FIG. 1
of the appended drawings illustrates an inner lamination
30
of a known construction for a linear motor. This inner lamination
30
is planar and usually stamped from a piece of sheet metal material having magnetic characteristics. The inner lamination
30
has a generally “U” shaped base
31
incorporating a pair of coplanar wings
33
having a pointed end that may be defined as a flat tip
34
, as illustrated. Each inner lamination
30
has a recess or a cut-out
36
, into which is mounted a toroidal coil (not shown), to which electric current is applied.
FIGS. 2 and 3
illustrate the mounting of inner laminations
30
in a circular array to form the stator of a linear motor, and the bases
31
of the inner laminations
30
are secured around a first fixed member, which may be defined by a bushing, in which a shaft is reciprocated, or by the cylinder of a compressor, within which a piston is reciprocated. An array of outer laminations
20
is placed around a second fixed member, which may be defined by the inner face of a cup that houses the bushing or the compressor cylinder.
In the embodiment of the inner laminations
30
illustrated in
FIGS. 1 and 2
, the flat tip
34
of the upper wing
33
defines the available area for welding or gluing the array of laminations to a mounting member such as a cylinder flange or an annular connecting element, as described ahead. This substantially limited surface area, defined by the thickness of the lamination itself, may not be adequate to assure good fixation and mounting of the array of inner laminations
30
.
One way to form the array of inner laminations
30
in a linear compressor is shown in FIG.
4
. In this construction, a cylinder
10
of the compressor has a center bore in which the piston (not shown) is reciprocated. Around the outer periphery of part of the cylinder
10
are mounted the bases
31
of an array of inner laminations
30
, which are secured to the external periphery of the cylinder
10
or any other suitable support means mounted to the cylinder. The laminations of the array of outer laminations
20
are in the form of individual pieces mounted around the interior of a circular wall of a cup (not shown). The upper ends of the outer laminations
20
are also in the form of a flat tip affixed to the lower face of a flange
10
a
incorporated to and extended radially from the cylinder
10
, and said fixation to the lower face of the flange
10
a
is achieved by an adhesive or by welding. Alternatively, the outer laminations
20
can be mounted to a support provided on the wall of the cup, within which the cylinder is positioned.
FIG. 5
shows another type of lamination mounting arrangement for the motor of a linear compressor, such as described in the co-pending patent application of the same applicant. In the mounting illustrated in
FIG. 5
, the cylinder
10
of the compressor does not have the flange boa, which makes the manufacture of the cylinder relatively complex and expensive. In this embodiment of
FIG. 5
, the inner laminations
30
have their wings
33
provided with flat tips
34
. The ends of the outer laminations
20
are also flat in this embodiment, in which a connecting ring
40
, of a nonmagnetic material, is mounted to the upper ends of the inner laminations
30
and the outer laminations
20
, and affixed to said ends by adhesive or by welding. Thus, there is provided a suspension mounting of the outer laminations
20
through the connecting ring
40
that is attached to the inner laminations
30
, these in turn being attached to the cylinder
10
.
The area, by which either the lower face of the flange
10
a
of the cylinder
10
of the structure illustrated in
FIG. 4
or the lower face of the connecting ring
40
of the construction illustrated in
FIG. 5
can be attached to the upper end of the inner laminations
30
and the outer laminations
20
, is only that defined by the thickness of each lamination. Where the laminations are thin, the mounting is not very stable. In the case of the outer laminations
20
, the end fixation area of each lamination is not critical due to the relatively small radial width of the outer laminations
20
, which allows maintaining them very close to each other throughout the radial width thereof. In this case, the end fixation areas are practically associated to each other, facilitating the fixation thereof by glue or welding.
Nevertheless, in the case of the inner laminations
30
, the radial width thereof makes them divergent relative to each other, from the inner edge affixed to the cylinder
10
towards the outer edge
35
. The outer edges
35
are quite separated from each other, and so are the flat tips
34
of the upper ends, avoiding the fixation of all said flat tips
34
as a single surface. Thus, for the inner laminations
30
, the upper fixation area is critical to provide for better fixation of said laminations.
Another problem of the constructions described above is the difficulty of maintaining the inner laminations
30
spaced apart from each other by a certain angle around the entire external periphery of the compressor cylinder.
Accordingly, it would be desirable to provide a lamination having a structure that can be arranged in a circular array, such as that defined by the inner laminations
30
and the outer laminations
20
of a linear motor, in order to provide a larger surface area for fixation of at least one of the ends thereof to another member.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide an improved structure for a lamination, which is to be arranged in a array of laminations, such as used in a linear motor, in order to provide a larger surface area for fixation of at least one end of each lamination of the array to an external member.
SUMMARY OF THE INVENTION
In accordance with the invention, a lamination for a linear motor is formed of a piece of metal having magnetic properties and presenting a structure comprising a base to be placed adjacent to a fixed member, such as the outer surface of a bushing or the cylinder of a linear compressor, or against the inner surface of another fixed member, such as a cup to house the bushing or the cylinder. The lamination incorporates at least one coplanar wing extending from the base and having an end that is bent at an angle in relation to the common plane of the base and the wing, to form a flap with a surface area corresponding to the size of the flap. A plurality of laminations is arranged in a circular array to form the linear motor. The flaps are provided at the upper end of the laminations of the array, in order to lie in a common plane to form a relatively large surface area for mounting of al external member to said array of laminations.
REFERENCES:
patent: 3591819 (1971-07-01), Laing et al.
patent: 3828211 (1974-08-01), Laronze
patent: 4206373 (1980-06-01), Hurst
patent:
Darby & Darby
Empresa Brasileira de Compressores S.A. - Embraco
Le Dang
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