Pumps – Motor driven – Resiliently mounted pump or motor
Reexamination Certificate
1999-08-09
2001-06-26
Thorpe, Timothy S. (Department: 3746)
Pumps
Motor driven
Resiliently mounted pump or motor
Reexamination Certificate
active
06250895
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a linear compressor to which little load in a direction perpendicular to a direction of reciprocating motion of a piston is applied, and more particularly, to a linear compressor in which a linear motor is disposed around an outer periphery of a piston, and it is possible to easily mount the linear motor with high precision.
BACKGROUND TECHNIQUE
It is said that HCFC-based refrigerant, such as R22, which is utilized in an air conditioner and is a stable compound, destroys the ozone layer. In recent years, HFC-based refrigerants are utilized as alternative refrigerants of HCFC, but these HFC-based refrigerants have the nature for facilitating global warming. Therefore, there is a tendency to start employing HC-based refrigerants which do not destroy the ozone layer or largely affect global warming. However, since the HC-based refrigerants are flammable, it is necessary to prevent explosion or ignition so as to ensure safety, and it is required to reduce the amount of use of the refrigerant to the utmost. On the other hand, HC-based refrigerants do not have lubricity and are prone to be solved into lubricants. Therefore, when HC-based refrigerants are used, the use of an oil free or oil poor compressor is required, and a linear compressor in which little load is applied in a direction perpendicular to an axis of a piston.
Here, a linear compressor in which a linear motor is disposed around an outer periphery of a piston is disclosed in Japanese Patent Application Laid-open No. H8-144954, Japanese Patent Application Laid-open No.H4-34760 and U.S. Pat. No. 5,525,845.
However, in the above prior art, there is no suggestion to easily mount a movable member of a linear motor to a piston with high precision.
It is described in Japanese Patent Application Laid-open No.H4-34760 that a piston is provided at its end with a flange, and the flange is concentrically provided with a cylindrical bobbin. However, there is no description as to how the bobbin is provided concentrically. Further, as shown in
FIG. 1
, of the publication the flange is provided merely for mounting the bobbin by a screw. Therefore, the mounting precision of the bobbin to the piston can not be enhanced by this prior art.
Therefore, it is an object of the present invention to provide a linear compressor in which it is possible to easily mount a movable member of a linear motor to a piston with high precision.
Further, when the movable member is a permanent magnet, it is another object of the invention to provide a linear compressor in which it is possible to easily mount this permanent magnet with high precision.
DISCLOSURE OF THE INVENTION
According to a first aspect of the present invention, there is provided a linear compressor, comprising: a cylinder supported in a vessel by a supporting mechanism; a piston A concentric with the cylinder and movably supported along an axial direction of the cylinder, and a linear motor for forming a magnetic path by a movable member fixed to the piston and a stationary member fixed to the cylinder to generate a thrust force; the linear motor being disposed around an outer periphery of the piston, wherein the piston is provided with a flange having a side surface formed concentrically with an axis of the piston, the movable member is held by a cylindrical holding member, and the cylindrical holding member is fixed such that the cylindrical holding member is in contact with the side surface of the flange.
With this feature, since the side surface is concentric with the piston, the cylindrical holding member can also be provided concentrically with the piston. Since the cylindrical holding member holds the movable member, the movable member is disposed concentrically with the piston, and can be positioned precisely. Further, the mounting operation of the movable member is also easy. Furthermore, the overall length of the movable member and the piston constituting the moving member can be shortened, as compared with a structure in which the piston and the linear motor are juxtaposed in the moving direction. Even if the piston is slightly inclined, little influence is exerted on the gap of the movable member, which contributes to enhancement of efficiency of the compressor.
According to a second aspect of the present invention, there is provided a linear compressor, comprising: a cylinder supported in a vessel by a supporting mechanism; a piston concentric with the cylinder and movably supported along an axial direction of the cylinder, and a linear motor for forming a magnetic path by a movable member fixed to the piston and a stationary member fixed to the cylinder to generate a thrust force; the linear motor being disposed around an outer periphery of the piston, wherein the piston is provided with a flange which has a side surface formed concentrically with an axial of the piston and an end surface formed perpendicular to the axis of the piston, the movable member is held by a cylindrical holding member, and the cylindrical holding member is fixed such that the cylindrical holding member is in contact with the side surface and the end surface of the flange.
With this feature, the cylindrical holding member is disposed concentrically with the piston, and the movable member held by the cylindrical holding member is disposed concentrically with the piston and positioned precisely. Further, the mounting operation of the movable member is also easy. Furthermore, the overall length of the movable member and the piston constituting the moving member can be shortened as compared with a structure in which the piston and the linear motor are juxtaposed in the moving direction, even if the piston is slightly inclined, little influence is exerted on the gap of the movable member, which contributes to enhancement of efficiency of the compressor.
According to a third aspect, in the first or second aspect, the cylinder is provided with a flange portion, the flange portion is formed concentrically with an axis of the cylinder, the stationary member constituting the linear motor is formed cylindrically, and the stationary member is fixed to the flange portion.
With this feature, the stationary member can be disposed concentrically with the cylinder, the positional relation between the movable member and the stationary member disposed concentrically with the piston can be maintained precisely, and the gap between the movable member and the stationary member can be reduced. Therefore, the efficiency of the compressor can be enhanced.
According to a fourth aspect, in the third aspect, the movable member is a permanent magnet, and the stationary member is an outer yoke and a coil.
With this feature, since the stationary member is concentrically fixed to the cylinder side and the permanent magnet is concentrically held on the piston side, the positional precision therebetween is enhanced. Further, since the coil is the stationary member, it is easy to carry out wiring for energizing the coil.
According to a fifth aspect, in the first or second aspect, an outer peripheral surface of the cylinder is formed concentrically with an axis of the cylinder, the stationary member constituting the linear motor is formed cylindrically, and the stationary member is held by the cylinder such that the stationary member is in contact with the outer peripheral surface.
With this feature, the movable member is concentric with the stationary member, and it is possible to easily reduce the size and the gap, and to enhance the efficiency of the compressor.
According to a sixth aspect, in the fifth aspect, the movable member is a permanent magnet, and the stationary member in an inner yoke.
With this feature, both the permanent magnet and the inner yoke can be disposed concentrically with each other, and since the inner yoke is not disposed at the movable side, the weight of the movable member side can be reduced.
According to a seventh aspect, there is provided a linear compressor, comprising: a cylinder supported in a vessel by a supporting mechanism; a piston concentric with
Akazawa Teruyuki
Kawahara Sadao
Armstrong, Westerman Hattori, McLeland, and Naughton, LLP
Matsushita Electric - Industrial Co., Ltd.
Rodriguez William H.
Thorpe Timothy S.
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