JP2002048061A - Linear motor driving compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the service life of a plate spring by preventing the fracture thereof, and improve the service life of a linear motor compressor. SOLUTION: In this linear motor compressor, a piston or a cylinder as a driving unit is supported at a first and a second support points by using a plate spring. A ratio of the number of plate springs to be provided at the first and the second support points is set so as to coincide with a ratio of the strength of the external force in the direction crossing the moving direction of a driving unit and to be applied to the first and the second support points.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor driven compressor, and more particularly to a linear motor driven compression having a structure in which a movable portion is supported by a leaf spring.

[0002]

2. Description of the Related Art A linear motor driven compressor is a piston type (reciprocating type) compressor which reciprocates a piston (or a cylinder) along a predetermined direction, and a driving means for driving the piston (or a cylinder). Is a compressor employing a linear motor. The linear motor driven compressor adopts a linear motor, so that unlike a compressor using a rotary motor, vibration in the direction other than the direction of movement of the piston does not occur, and a pair of pistons are arranged facing each other. Therefore, there is a characteristic that vibration can be theoretically eliminated. Such a linear motor driven compressor is
For example, it is used for a regenerative refrigerator such as a Stirling refrigerator.

As shown in FIG. 1, a conventional linear motor driven compressor comprises a case 11, a cylinder 12, a piston 13 reciprocally inserted into the cylinder 12, and a piston rod connected to the piston 13. 14, a linear motor 15 for reciprocating the piston 13 via the piston rod 14, and a plurality (usually two sets) of leaf springs 16 supporting the piston rod 14.

Alternatively, as shown in FIG. 2, a conventional linear motor drive compressor includes a case 21, a cylinder 23 one end of which is closed by a block 22, and a hollow piston rod 24 fixed to the case 21. A piston 25 inserted into the cylinder 23, a linear motor 26 for reciprocating the cylinder 23, and a plurality (usually two sets) supporting the cylinder 23. ) And a leaf spring 27).

The leaf spring 16 or 27 is a diaphragm (disk-shaped) leaf spring made of a thin elastic metal, or FIG.
As shown in (a), (b) and (c), the leaf spring has a structure in which two ring members (or frame members having different sizes) made of a thin elastic metal and having different diameters are connected by a plurality of arms. . These leaf springs are provided at both ends of a magnetic circuit constituting the linear motor. Here, the leaf spring 1 is used.
Although the example in which the number of sheets 6 and 27 is set to one at each position is shown, the number of leaf springs is determined by the driving unit (piston 13, piston shaft 14, arm 17, and coil 18, or cylinder 23, block 22, Arm 28 and coil 2
9) is determined based on the total spring constant obtained based on the weight, operating frequency, gas spring constant, and the like. In other words, if the total spring constant required for the operation of the compressor is to be realized with a small number of leaf springs, the stress generated in each leaf spring will be large, and if it is to be realized with a large number of leaf springs, the stress will be small. The number of leaf springs is determined so that the stress generated in the spring is appropriate. In a conventional linear motor drive compressor, the same number of leaf springs having the same characteristics are arranged at two locations.

Returning to FIG. 1, the linear motor 15 has a coil 18 attached to an arm 17 connected to a piston rod 14 and a permanent magnet 19. Similarly, the linear motor 26 of FIG. 2 includes a coil 29 attached to an arm 28 connected to a cylinder 23 and a permanent magnet 30
And

In the linear motor driven compressor shown in FIG. 1, a piston 13 is driven by a linear motor 15 to
The compression of the refrigerant gas located therein is performed. FIG.
In the linear motor driven compressor, the cylinder 23 is driven by the linear motor 26 to compress the refrigerant gas located in the cylinder 23 (that is, between the block 22 and the piston 25). In each case, the compressed refrigerant gas is sent through a gas passage to an expander.

[0008] Such a linear motor driven compressor is disclosed in, for example, Utility Model Publication (Japanese Utility Model Registration No. 2).
No. 5,186,671).

[0009]

In the conventional linear motor drive compressor, the leaf spring supporting the drive section is easily broken,
There is a problem that its life is short.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the breakage of a leaf spring and extend the life thereof, thereby extending the life of a linear motor compressor.

[0011]

According to the present invention, there is provided a cylinder having a cylinder and a piston combined with the cylinder,
A linear motor drive compressor that drives one of the cylinder and the piston as a drive unit in a predetermined direction by a linear motor and compresses a gas located in the cylinder, wherein the drive unit is configured to be driven in the predetermined direction. A linear motor driven compressor supported at the first and second support points using a leaf spring having rigidity in a direction orthogonal to the predetermined direction, and having the same degree as the leaf spring. Using a plurality of leaf springs having characteristics, the ratio of the number of leaf springs used for the first support point to the number of leaf springs used for the second support point is set to the first support point. Linear motor drive compression, wherein the ratio of the absolute value of the force in the direction orthogonal to the predetermined direction to the absolute value of the force in the direction orthogonal to the predetermined direction on the second support point is matched. Machine is obtained.

[0012]

The cause of the breakage of the leaf spring in the conventional linear motor driven compressor was unknown, but was clarified by the research of the present inventor. That is, in the conventional linear motor drive compressor, the required total spring constant is determined based on the weight of the drive unit and the like, and the required number of leaf springs is determined based on the stress generated in one leaf spring. At this time, only the stress in the movement direction of the drive unit is considered as the stress generated in the leaf spring. That is, it has been found that the stress generated in the leaf spring in the direction perpendicular to the direction of movement of the driving unit is not considered at all, and that different magnitudes of stress occur in each leaf spring.

Therefore, in the present invention, each support point
The number of leaf springs provided at each support point is determined according to the force in the direction perpendicular to the direction of movement. as a result,
The stress generated in each of the leaf springs in the direction perpendicular to the direction of movement became equal, and fracture was less likely to occur.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

The configuration of the linear motor driven compressor according to the present embodiment is basically the same as that of the conventional one, and will be described below with reference to FIGS.

In the piston driven linear motor driven compressor shown in FIG. 1, the position of the center of gravity of the driving portion does not exist between the two support points of the leaf spring. In this case, the force acting on the center of gravity is F, the force acting on the first support point is F1, the distance from the center of gravity to the first support point is L1, and the force acting on the second support point is F.
2. If the distance from the center of gravity to the second support point is L2,
Absolute values of the forces | F1 | and | applied to the first and second support points
F2 | is | F1 | = L2 · | F | / (L2-L
1), | F2 | = L1 · | F | / (L2−L1).

In the cylinder-driven linear motor driven compressor shown in FIG. 2, the position of the center of gravity of the driving portion exists between the two support points. In this case, the force acting on the center of gravity is F, the force applied to the first support point is F1, the distance from the center of gravity to the first support point is L1, the force applied to the second support point is F2, and the force applied to the second support point is F2. Assuming that the distance to the support point is L2, the absolute values of the forces | F1 | and | F2 | applied to the first and second support points are | F1 | = L2 · F | / (L1 + L2), | F2 | = L
1 · | F | / (L1 + L2).

In the linear motor driven compressor according to the present embodiment, regardless of the drive type, in any case, the leaf spring supporting the two supporting points is based on the ratio of the absolute values of the forces applied to the two supporting points. Determine the number. For example, | F1 |: | F
In the case of 2 | = 1: 2, one leaf spring is provided at the first support point, and two leaf springs are provided at the second support point. In this case, all three leaf springs have the same characteristics. That is, each of the three leaf springs has a spring constant corresponding to 1/3 of the total spring constant required for the operation of the compressor.

[0019]

According to the present invention, in order to support the drive unit, the number of leaf springs provided at the first and second support points is reduced by the external force applied in the direction perpendicular to the direction of movement at each support point. By determining the ratio in accordance with the ratio, breakage of the leaf spring is less likely to occur, whereby the life of the linear motor driven compressor can be extended.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a piston-driven linear motor-driven compressor.

FIG. 2 is a diagram showing a configuration of a cylinder drive type linear motor drive compressor.

FIGS. 3A, 3B, and 3C are diagrams illustrating examples of the structure of a leaf spring. FIG.

[Explanation of symbols]

 11 Case 12 Cylinder 13 Piston 14 Piston rod 15 Linear motor 16 Leaf spring 17 Arm 18 Coil 19 Permanent magnet 21 Case 22 Block 23 Cylinder 24 Piston rod 25 Piston 26 Linear motor 27 Leaf spring 28 Arm 29 Coil 30 Permanent magnet

Claims (1)

[Claims] A cylinder and a piston combined with the cylinder, wherein one of the cylinder and the piston is driven in a predetermined direction by a linear motor as a drive unit to remove gas located in the cylinder. A linear motor drive compressor for compressing, wherein the drive unit has a degree of freedom in the predetermined direction and a first and a second support using a leaf spring having rigidity in a direction orthogonal to the predetermined direction. In a linear motor drive compressor supported at points, a plurality of leaf springs having the same characteristics are used as the leaf springs, and the number of leaf springs used at the first support point and the second
The ratio of the number of leaf springs used for the support point is defined by the absolute value of the force in the direction orthogonal to the predetermined direction applied to the first support point and the absolute value of the force in the direction orthogonal to the predetermined direction applied to the second support point A linear motor driven compressor characterized in that the ratio of the force to the absolute value of the direction is matched.