RESONANT ARRANGEMENT FOR A LINEAR COMPRESSOR

Description

Field of the Invention

[0001] The present invention refers, in general, to a constructive arrangement for a resonant compressor of the type driven by a linear motor to be applied in refrigeration systems and which presents a piston reciprocating inside a cylinder.

Background of the Invention

[0002] In a reciprocating compressor driven by a linear motor, the gas suction and gas compression operations are performed by the reciprocating axial movements of the piston inside a cylinder, which is closed by a cylinder head and mounted within a hermetic shell, in the cylinder head being positioned the suction and discharge valves that control the admission and discharge of the gas in relation to the cylinder. The piston is driven by an actuating means that supports magnetic components driven by a linear motor affixed to the shell of the compressor. A linear compressor having a resonant arrangement as defined in the pre-characterizing portion of claim 1 is known e.g. from document EP 0 909 895 A.

[0003] In some constructions, the piston is mounted against a resonant spring means in the form of an assembly of flat springs, affixed to the hermetic shell of the compressor to operate as guides to the axial displacement of the piston and make the whole assembly act resonantly in a predetermined frequency, allowing the linear motor to be adequately dimensioned to continuously supply energy to the compressor upon operation.

[0004] The piston is mounted against the spring assembly through a flexible rod, said spring assembly is rigidly mounted against the cylinder, and the piston, the actuator, the magnetic component, the flexible rod, and the assembly of flat springs form together the resonant assembly of the compressor.

[0005] In this construction, the piston is mounted against an assembly of flat springs made of a spring steel plate, through a flexible rod that has the function to neutralize the forces resulting from errors occurred during production and assembly of the parts, in order not to transmit said forces in their totality to the piston, avoiding the wear of said piston in relation to the cylinder.

[0006] This construction presents some disadvantages, such as the need to have a flexible rod to neutralize the forces resulting from the errors occurred during production and assembly of the parts. This flexible rod is also a relatively difficult component to be obtained, since it must be produced with special materials. Furthermore, such flat springs are very expensive, as they require very sophisticated cutting and finishing processes.

[0007] In another known construction, the assembly of flat springs is replaced by a system of helical springs, in which a first helical spring is mounted between the actuating means and the cylinder, and a second helical spring is mounted between the actuating means and the shell of the compressor and, in this construction, the resonant assembly of the compressor is formed by the piston, the actuating means, the magnet, and the helical springs.

[0008] This construction also presents disadvantages, such as requiring a compressor with larger dimensions, as a function of the need to use a pair of helical springs, which cannot be properly affixed to be submitted to traction forces.

[0009] Moreover, the helical springs have the characteristic of generating eccentric and shearing forces on the surfaces on which they are seated, provoking forces on the bearings of the piston of the compressor, generating noise and wear and reducing the life of the compressor.

Objects of the Invention

[0010] Thus, it is an object of the present invention to provide a resonant system for a linear compressor, presenting an easy and reliable assembly and fixation, which allows said resonant system to be submitted to traction and compressive forces during operation of the compressor, without losing the positioning in relation to the parts to which it is affixed, and which does not present radial and lateral force components during the movement of the piston that may result in radial forces to the piston.

[0011] A further object of the present invention is to provide a resonant system of low cost and which dispenses the use of the flexible rod and of the flat or helical springs.

Summary of the Invention

[0012] These and other objectives are achieved through a resonant arrangement for a linear compressor, comprising a non-resonant assembly formed by a motor and a cylinder; a resonant assembly formed by a piston reciprocating inside the cylinder; an actuating means operatively coupling the piston to the motor, and at least one spring means presenting an elongated tubular body, coaxial to the axis of the piston, and which is operatively coupled to the actuating means and to the non-resonant assembly, said tubular body having at least part of the extension thereof folded in circumferential sectors, each circumferential sector being elastically deformed in the axial direction upon the displacement of the piston.

Brief Description of the Drawings

[0013] The invention will be described below, with reference to the enclosed drawings, in which:

Figure 1 is a schematic longitudinal diametrical sectional view of a hermetic compressor of the type driven by a linear motor and presenting a resonant means, constructed according to the prior art;

Figure 2 is a schematic longitudinal diametrical sectional view of a hermetic compressor of the type driven by a linear motor and presenting another construction for the resonant means of the prior art;

Figure 3 is a schematic longitudinal diametrical sectional view of a hermetic compressor of the type driven by a linear motor and presenting a resonant means constructed according to the present invention;

Figure 4 illustrate, schematically, the compressor shown in figure 3, in a constructive variation of the present invention;

Figure 5 is a schematic lateral view of the resonant means of the present invention; and

Figure 6 is a schematic perspective view of the resonant means of the present invention illustrated in figure 5.

Description of the Illustrated Embodiments

[0014] The present invention will be described in relation to a reciprocating compressor driven by a linear motor of the type used in refrigeration systems and comprising a motor-compressor assembly, including a non-resonant assembly formed by a linear motor and a cylinder 1, and a resonant assembly formed by a piston 2 reciprocating inside the cylinder 1, and an actuating means 3, external to the cylinder 1 and carrying a magnet 4 that is axially impelled upon energization of the linear motor, said actuating means 3 operatively coupling the piston 2 to the linear motor.

[0015] According to the prior art construction illustrated in figures 1 and 2, the components mentioned above are mounted inside a hermetic shell 10.

[0016] As illustrated in the enclosed figures, the linear motor is mounted around the cylinder 1 and the piston 2 and comprises a stack of internal laminations 5 with a coil 6 inserted therein, and a stack of external laminations 7.

[0017] In the construction illustrated in figures 1 and 2, the compressor also includes conventional resonant spring means, mounted in constant compression to the resonant assembly and to the non-resonant assembly, and which are elastically axially deformable in the displacement direction of the piston 2.

[0018] In the construction of figure 1, the compressor comprises a spring means, in the form of an assembly of flat springs 10 made of a spring steel plate and to which is mounted the piston 2 through a flexible rod 8.

[0019] In the embodiment of figure 2, the compressor comprises a pair of spring means, for example a pair of helical springs 20, a first helical spring 20 mounted between the actuating means 3 and the cylinder 1, and a second helical spring 20 mounted between said actuating means 3 and the shell 10 of the compressor.

[0020] According to the illustrations, the cylinder 1 has an end closed by a valve plate 30, provided with a suction valve 31 and a discharge valve 32, which allows the selective fluid communication between a compression chamber 9 defined between a top portion of the piston 2 and the valve plate 30 and respective internal portions of a cylinder head 40 that are respectively maintained in fluid communication with the low and high pressure sides of the refrigeration system to which the compressor is coupled.

[0021] These constructions present the disadvantages discussed above.

[0022] According to the present invention, the prior art disadvantages are avoided with a resonant arrangement for a linear compressor that comprises at least one spring means presenting an elongated tubular body 50, which is coaxial to the axis of the piston 2 and has an end 51 operatively coupled to the actuating means 3, and an opposite end 52 operatively coupled to the non-resonant assembly, said tubular body 50 having at least part of its extension folded in circumferential sectors 53 that are symmetric in relation to the axis of said tubular body 50, and for example, orthogonal to the axis of the piston 2, each circumferential sector 53 being elastically deformed in the axial direction upon the displacement of piston 2.

[0023] According to a way of carrying out the present invention, the circumferential sectors 53 present the same cross section profile, for example a substantially "V" shaped profile, such as illustrated in figure 5, or a substantially "U" shaped profile.

[0024] In the construction illustrated in which the circumferential sector 53 has a "V" shaped profile, the elastic deformation of each said circumferential sector 53 upon displacement of the piston occurs by variation of its respective dihedral angle.

[0025] Although in the illustrated constructive alternative the circumferential sectors 53 present the same dihedral angle, it should be understood that the solutions in which the circumferential sectors 53 present different cross section profiles along the longitudinal extension of the tubular body 50 and different dihedral angles to said circumferential sectors 53 are also possible.

[0026] According to a way of carrying out the present invention, the tubular body is hollow, allowing for the fluid communication between the compression chamber 9 and the interior of the shell 10, which in this case is of the conventional hermetic type.

[0027] In the embodiment of the invention, as illustrated, the tubular body 50 presents a non-hollow lateral surface 54. In this case, since an end 51 of the tubular body 50 is hermetically affixed to the cylinder 1, and the opposite end 52 is hermetically affixed to the actuating means 3, said tubular body 50 blocks the fluid communication between the compression chamber 9 and the exterior of cylinder 1 through gaps existing between the piston 2 and the cylinder 1. In this construction, the shell of the compressor, if provided, does not need to be hermetic, since the sealing between the compression chamber 9 and the interior of said shell is obtained by the tubular body 50.

[0028] According to the illustration in figure 3, the compressor further presents another spring means in the form of a tubular body 50, having an end 51 affixed to the actuating means 3, and the other end 52 affixed to the shell 10. The fixation of each of the ends 51, 52 of each tubular body 50 to the respective parts defined by the cylinder 1, the actuating means 3, and the shell 10 is achieved for example, by one of the processes of welding, gluing or screwing.

[0029] In a form of executing the invention, each of the ends 51, 52 of each tubular body 50 is defined by a respective tubular extension not presenting the circumferential sectors 53 and which is dimensioned to provide a fitting to the respective part to which it is affixed. However, other constructive forms for said ends 51, 52 are possible, such as radial projections to be orthogonally affixed to the axis of the piston 2.

[0030] In the illustrated construction, each part to which is affixed an adjacent end 51, 52 of the tubular body 50 is provided with at least one circumferential tooth that is coaxial to the axis of the piston 2 in order to fit said respective end 51, 52.

[0031] According to the illustrations in figure 3, a lower end portion of the cylinder 1 is provided with an annular cutting 1a, which defines the tooth for the fixation of an adjacent end 51 of the tubular body 50, and the actuating means 3 is provided with a first annular tooth 3a facing the cylinder 1 and securing the other end 52 of the tubular body 50.

[0032] In the construction presenting two spring means, such as illustrated in figure 4, the actuating means 3 is further provided with a second annular tooth 3b, facing a lower portion of the shell 10 in order to affix an end 51 of other tubular body 50. In this construction, the shell 10 presents a respective annular salience, which is coaxial and aligned in relation to the second tooth 3b of the actuating means 3 that secures the other end 52 of the tubular body 50. In the illustrated constructions, the circumferential teeth are continuous, coaxial and axially aligned to each other.

Claims

1. A resonant arrangement for a linear compressor, comprising a non-resonant assembly formed by a motor and a cylinder (1); a resonant assembly formed by a piston (2) reciprocating inside the cylinder (1); an actuating means (3) operatively coupling the piston (2) to the motor, and at least one spring means, mounted to the resonant assembly and which is elastically and axially deformed toward the displacement of the piston (2), characterized in that the spring means presents an elongated tubular body (50), which is coaxial in relation to the axis of the piston (2) and has and end (51) operatively coupled to the actuating means (3) and an opposite end (52) operatively coupled to the non-resonant assembly, said tubular body (50) having at least part of the extension thereof folded in circumferential sectors (53) that are symmetric in relation to the axis of said tubular body (50), each circumferential sector (53) being elastically deformed in the axial direction upon displacement of the piston (2).

2. The resonant arrangement according to claim 1, characterized in that the circumferential sectors (53) present the same cross section profile.

3. The resonant arrangement according to claim 2, characterized in that each circumferential sector (53) presents a substantially "V" shaped profile, each circumferential sector (53) being elastically deformed by variation of its respective dihedral angle.

4. The resonant arrangement according to claim 3, characterized in that the circumferential sectors (53) present the same dihedral angle.

5. The resonant arrangement according to claim 1, characterized in that the circumferential sectors (53) are orthogonal to the longitudinal axis of the tubular body (50).

6. The resonant arrangement according to claim 1, characterized in that the tubular body (50) presents a non-hollow lateral surface (54).

7. The resonant arrangement according to claim 1, characterized in that the fixation of each end (51, 52) to the adjacent part defined by the cylinder (1) and the actuating means (3) is obtained by one of the processes of welding, gluing and screwing.

8. The resonant arrangement according to claim 7, characterized in that each one of the ends (51, 52) of the tubular body (50) is defined by a respective tubular extension not presenting the circumferential sectors (53) and dimensioned to provide a fitting to the respective part to which it is affixed.

9. The resonant arrangement according to claim 8, characterized in that each part to which is affixed an adjacent end (51, 52) of the tubular body (50) is provided with at least one circumferential tooth (la, 3a, 3b, 10a) which is coaxial to the axis of the piston (1) for fitting said respective end (51, 52).

10. The resonant arrangement according to claim 9, characterized in that each circumferential tooth (la, 3a, 3b, 10a) is continuous.

11. The resonant arrangement according to claim 6, in which the cylinder (1) is closed by a cylinder head (30) defining between a top portion of the piston (2) and said cylinder head (30) a compression chamber (9), characterized in that the tubular body (50) has an end (51) hermetically affixed to the cylinder (1) and the opposite end (52) hermetically affixed to the actuating means (3), in order to block the fluid communication between the compression chamber (9) and the exterior of the cylinder (1) through gaps existing between the piston (2) and the cylinder (1).

12. The resonant arrangement according to claim 1, in which the hermetic compressor comprises a hermetic shell (10), inside which are mounted the resonant and the non-resonant assemblies, characterized in that it comprises another spring means in the form of a tubular body (50) having an end (51) affixed to the actuating means (3) and the other end (52) affixed to the shell (10).

Ansprüche

1. Resonanzanordnung für einen Linearverdichter, mit einer nicht an der Resonanz teilnehmenden Baugruppe, die durch einen Motor und einen Zylinder (1) gebildet wird, mit einer Resonanzbaugruppe, die durch einen im Inneren des Zylinders (1) hin- und herlaufenden Kolben (2) gebildet wird, mit einer Betätigungseinrichtung (3), die den Kolben (2) betätigbar mit dem Motor verbindet, und mit mindestens einer Federeinrichtung, die an der Resonanzbaugruppe montiert ist und in Richtung der Verschiebung des Kolbens (2) elastisch und axial verformt wird, dadurch gekennzeichnet, daß die Federeinrichtung einen langgestreckten rohrförmigen Körper (50) aufweist, der koaxial zur Achse des Kolbens (2) verläuft und dessen eines Ende (51) betätigbar mit der Betätigungseinrichtung (3) und dessen gegenüberliegendes Ende (52) betätigbar mit der nicht an der Resonanz teilnehmenden Baugruppe gekoppelt ist, wobei der rohförmige Körper (50) zumindest über einen Teil seiner Erstreckung in entlang dem Umfang verlaufende Sektoren (53) gefaltet ist, die symmetrisch zur Achse des rohrförmigen Körpers (50) liegen, wobei jeder in Umfangsrichtung verlaufende Sektor (53) bei einer Verschiebung des Kolbens (2) elastisch in axialer Richtung verformt wird.

2. Resonanzanordnung nach Anspruch 1, dadurch gekennzeichnet, daß die in Umfangsrichtung verlaufenden Sektoren (53) das gleiche Querschnittsprofil haben.

3. Resonanzanordnung nach Anspruch 2, dadurch gekennzeichnet, daß jeder in Umfangsrichtung verlaufende Sektor (53) ein im wesentlichen "V"-förmiges Profil aufweist, wobei jeder in Umfangsrichtung verlaufende Sektor (53) durch Änderung seines Dihedralwinkels elastisch verformt wird.

4. Resonanzanordnung nach Anspruch 3, dadurch gekennzeichnet, daß die in Umfangsrichtung verlaufenden Sektoren (53) den gleichen Dihedralwinkel aufweisen.

5. Resonanzanordnung nach Anspruch 1, dadurch gekennzeichnet, daß die in Umfangsrichtung verlaufenden Sektoren (53) senkrecht zur Längsachse des rohrförmigen Körpers (50) verlaufen.

6. Resonanzanordnung nach Anspruch 1, dadurch gekennzeichnet, daß der rohrförmige Körper (50) eine nicht-hohle Seitenfläche (54) aufweist.

7. Resonanzanordnung nach Anspruch 1, dadurch gekennzeichnet, daß die Befestigung jedes Endes (51, 52) am benachbarten Teil, das durch den Zylinder (1) und die Betätigungseinrichtung (3) festgelegt ist, durch eines der Verfahren: Schweißen, Kleben und Schrauben erhalten wird.

8. Resonanzanordnung nach Anspruch 7, dadurch gekennzeichnet, daß jedes der Enden (51, 52) des rohrförmigen Körpers (50) durch eine entsprechende rohrförmige Erweiterung festgelegt ist, die nicht die in Umfangsrichtung verlaufenden Sektoren (53) aufweist und so bemessen ist, daß sie ein Anschlußstück zum entsprechenden Teil, an dem es befestigt werden soll, bereitstellt.

9. Resonanzanordnung nach Anspruch 8, dadurch gekennzeichnet, daß jedes Teil, an dem ein benachbartes Ende (51, 52) des rohrförmigen Körpers (50) befestigt ist, mit mindestens einem in Umfangsrichtung verlaufenden Absatz (1a, 3a, 3b, 10a) versehen ist, der koaxial zur Achse des Kolbens (1) zum Anschließen des jeweiligen Endes (51, 52) verläuft.

10. Resonanzanordnung nach Anspruch 9, dadurch gekennzeichnet, daß jeder in Umfangsrichtung verlaufende Absatz (1a, 3a, 3b, 10a) durchgängig ausgebildet ist.

11. Resonanzanordnung nach Anspruch 6, bei welcher der Zylinder (1) durch einen Zylinderkopf (30) verschlossen ist, der zwischen einem oberen Abschnitt des Kolbens (2) und dem Zylinderkopf (30) eine Kompressionskammer (9) festlegt, dadurch gekennzeichnet, daß der rohrförmige Körper (50) mit einem Ende (51) hermetisch dicht am Zylinder (1) und mit seinem gegenüberliegenden Ende (52) hermetisch dicht an der Betätigungseinrichtung (3) befestigt ist, um die zwischen der Kompressionskammer (9) und der Außenseite des Zylinders (1) durch Zwischenräume zwischen dem Kolben (2) und dem Zylinder (1) bestehende Fluidverbindung zu blockieren.

12. Resonanzanordnung nach Anspruch 1, bei welcher der hermetische Verdichter ein hermetisches Gehäuse (10) aufweist, in dessen Innerem die Resonanz- und die nicht an der Resonanz teilnehmenden Baugruppen montiert sind, wobei die Anordnung dadurch gekennzeichnet ist, daß sie eine weitere Federeinrichtung in Form eines rohrförmigen Körpers (50) aufweist, dessen eines Ende (51) an der Betätigungseinrichtung (3) und dessen anderes Ende (52) am Gehäuse (10) befestigt ist.

Revendications

1. Agencement résonnant destiné à un compresseur linéaire, comprenant un ensemble non résonnant formé par un moteur et un cylindre (1), un ensemble résonnant formé par un piston (2) effectuant un mouvement de va-et-vient à l'intérieur du cylindre (1), un moyen d'actionnement (3) couplant de façon fonctionnelle le piston (2) au moteur, et au moins un moyen de ressort, monté sur l'ensemble résonnant et qui est déformé élastiquement et axialement en direction du déplacement du piston (2), caractérisé en ce que le moyen de ressort présente un corps tubulaire allongé (50), qui est coaxial par rapport à l'axe du piston (2) et comporte une extrémité (51) couplée de façon fonctionnelle au moyen d'actionnement (3) et une extrémité opposée (52) couplée de façon fonctionnelle à l'ensemble non résonnant, ledit corps tubulaire (50) ayant au moins une partie du prolongement de celui-ci pliée en secteurs circonférentiels (53) qui sont symétriques par rapport à l'axe dudit corps tubulaire (50), chaque secteur circonférentiel (53) étant déformé élastiquement dans la direction axiale lors du déplacement du piston (2).

2. Agencement résonnant selon la revendication 1, caractérisé en ce que les secteurs circonférentiels (53) présentent le même profil en section transversale.

3. Agencement résonnant selon la revendication 2, caractérisé en ce que chaque secteur circonférentiel (53) présente un profil pratiquement en forme de "V", chaque secteur circonférentiel (53) étant élastiquement déformé par la variation de son angle dièdre respectif.

4. Agencement résonnant selon la revendication 3, caractérisé en ce que les secteurs circonférentiels (53) présentent le même angle dièdre.

5. Agencement résonnant selon la revendication 1, caractérisé en ce que les secteurs circonférentiels (53) sont orthogonaux à l'axe longitudinal du corps tubulaire (50).

6. Agencement résonnant selon la revendication 1, caractérisé en ce que le corps tubulaire (50) présente une surface latérale non creuse (54).

7. Agencement résonnant selon la revendication 1, caractérisé en ce que la fixation de chaque extrémité (51, 52) à la partie adjacente définie par le cylindre (1) et le moyen d'actionnement (3) est obtenue par l'un des processus tels que le soudage, le collage et le vissage.

8. Agencement résonnant selon la revendication 7, caractérisé en ce que chacune des extrémités (51, 52) du corps tubulaire (50) est définie par un prolongement tubulaire respectif ne présentant pas les secteurs circonférentiels (53) et dimensionnée pour fournir un raccord à la partie respective à laquelle elle est fixée.

9. Agencement résonnant selon la revendication 8, caractérisé en ce que chaque partie à laquelle est fixée une extrémité adjacente (51, 52) du corps tubulaire (50) est munie d'au moins une dent circonférentielle (la, 3a, 3b, 10a) qui est coaxiale par rapport à l'axe du piston (1) afin d'adapter ladite extrémité respective (51, 52).

10. Agencement résonnant selon la revendication 9, caractérisé en ce que chaque dent circonférentielle (la, 3a, 3b, 10a) est continue.

11. Agencement résonnant selon la revendication 6, dans lequel le cylindre (1) est fermé par une tête de cylindre (30) définissant entre une partie supérieure du piston (2) et ladite tête de cylindre (30) une chambre de compression (9), caractérisé en ce que le corps tubulaire (50) comporte une extrémité (51) fixée de façon hermétique au cylindre (1) et l'extrémité opposée (52) fixée hermétiquement au moyen d'actionnement (3), de manière à bloquer la communication de fluide entre la chambre de compression (9) et l'extrémité du cylindre (1) par l'intermédiaire d'espacements existant entre le piston (2) et le cylindre (1).

12. Agencement résonnant selon la revendication 1, dans lequel le compresseur hermétique comprend une coque hermétique (10), à l'intérieur de laquelle sont montés l'ensemble résonnant et l'ensemble non résonnant, caractérisé en ce qu'il comprend un autre moyen de ressort sous la forme d'un corps tubulaire (50) ayant une extrémité (51) fixée au moyen d'actionnement (3) et l'autre extrémité (52) fixée à la coque (10).

Drawing