WO2013097008A1

WO2013097008A1 - Linear compressor based on a resonant oscillating mechanism

Info

Publication number: WO2013097008A1
Application number: PCT/BR2012/000513
Authority: WO
Inventors: Paulo Rogerio Carrara Couto; Celso Kenzo Takemori; Wilfred ROETTGER; Erich Bernhard Lilie DIETMAR
Original assignee: Whirlpool S.A
Priority date: 2011-12-26
Filing date: 2012-12-12
Publication date: 2013-07-04
Also published as: TW201346138A; BRPI1105436A2; AR089471A1

Abstract

The present invention refers to linear compressor which is based on a double resonant oscillating mechanism and which has functional elements that are essentially mirrored. More specifically, it is revealed a linear compressor comprising at least one resonant spring (2) which is placed in the interior of at least one shell (7), at least two compression assemblies, at least two heads (3), and at least two active mass portions (1 ) which are kept in balance one with the other, and further in balance with the resonant spring (2). Additionally, the active mass portions (1 ) are synchronously operational in accordance with the anti-phase that is established by the resonant spring (1 ), and the same are composed of at least one piston (5) and at least one movable part (61 ) of at least one linear engine.

Description

"LINEAR COMPRESSOR BASED ON A RESONANT OSCILLATING MECHANISM" Field of the Invention

The present invention refers to a linear compressor based in an oscillating mechanism and, in especial, based on a double resonant oscillating mechanism.

More specifically, the present invention reveals a linear compressor composed of two compression assemblies which are oppositely arranged and resonantly conjugated.

Background of the Invention

As already known by the skilled in the art, the prior art comprises a wide range of linear compressors, wherein the majority part of such compressors is based on oscillating mechanisms.

Generally, such mechanisms consist of positioning the mass on the opposed ends of a spring that is susceptible of resilient deformation. According to the functioning principle of such mechanisms, it is generated work by the oscillating shift of one or both mass portions, which are shifted from its balance/rest position (by an external force) to a first limit position, and, then, from the first limit position to a second limit position (normally opposed to the first limit position). Evidently, such oscillating shift is commanded and amplified by the spring, which is deformed along its length during the functioning of the mechanism,

One example of the oscillating mechanism that is used in linear compressors is schematically illustrated in figures 1A and 1 B, which - respectively - illustrates a block diagram and a schematic cut of a simplified model of a linear compressor that is based on an equally simplified oscillating mechanism.

Such oscillating mechanism fundamentally comprises a spring M, a shell C, and an active mass MA which is composed by the association of a piston P, a connecting rod B, and the movable part M1 of the linear engine. The shell C comprises a casing body for most items that compose the linear compressor, including the fixing block BF, which interconnects the elements of the active mass to the shell C. Conventionally, it is also provided internal damping systems SI between the fixing block BF and the shell C. In this case, the fixing block BF (and, consequently, the cited shell C) is fundamentally associated with one of the ends of the spring M. The active mass (mass whose shift is reutilized as work) is functionally associated with the other end of the spring M. Thus, the linear engine is responsible for the oscillating linear shift of the entire active mass MA, and, consequently, for the oscillating linear shift of the piston P that is placed in the interior of a compression cylinder belonging to the compressor head. The motion of the piston P in the interior of the cylinder is responsible for the compression of the working fluid of the compressor.

Although this oscillating mechanism is relatively functional, it is noted that the shift of its active mass MA is limited to the maximum length of the spring M, which, as a result, defines the extension of the motion of the active mass. Another constructive option of the above-mentioned oscillating mechanism is illustrated in figures 2A and 2B, which - respectively - illustrate a block diagram and a schematic cut of a duplicate model of a linear compressor that is based on an equally duplicate oscillating mechanism.

Such mechanism basically comprises a single Shell C, at least one spring M, and two active mass portions MA, both also composed by the association of a piston P, a connecting rod B, and the movable portion M1 of the linear engine. The shell C comprises a casing body for most items that compose the linear compressor, including the fixing block BF, which interconnects the elements of the active mass portions to the shell C. Conventionally, it is also provided internal damping systems SI between the fixing block BF and the shell C. In this case, the fixing block BF (and, consequently, the cited shell C) is fundamentally associated with one of the ends of the spring M. The active mass portions MA are functionally associated with the spring M (not necessarily by the end of the spring). Thus, each linear engine is responsible for the oscillating linear shift of its respective active mass MA, and, consequently, for the oscillating linear shift of the piston P that is placed in the interior of a compression cylinder belonging to the compressor head. The motion of the piston P in the interior of the cylinder is responsible for the compression of the working fluid of the compressor.

Although such construction is capable of doubling the capacity of a "simple" linear compressor, it is noted being necessary that such construction contains almost twice times the number of elements that exist in a "simple" linear compressor, demanding, also, twice times the size of the oscillating mechanism. This feature, considering fundamental sizing aspects, can be a negative feature for several apparatus and devices that utilize such types of compressor. Moreover, it is further noted that those two pistons P (each one belonging to one active mass MA) are always shifted in the same direction, rendering, therefore, the mechanism intrinsically imbalanced.

The current prior art further provides other constructive forms for the obtainment of a linear compressor that is based on a duplicate oscillating mechanism, wherein the optional construction is illustrates in figures 3A and 3B. The large difference of such construction in relation to the construction of figures 2A and 2B refers to the lack of suspension. Thus, the imbalance is fully transmitted to the shell of the compressor, which suffers from a high vibration level.

Great part of the above-mentioned oscillating mechanism limitations is caused by the fact that only one of the ends of the spring M is functionally associated with an active mass MA, while the other end of the same spring M is (directly or indirectly) associated with the shell, which has a null linear motion. In other words, the electrical energy that is applied to such types of mechanisms is converted into motion in only one of the ends of the spring M, wherein the other end of the spring M is incapable of transforming any oscillating boost into work.

In order to solve, in part, the above-mentioned limitations, it is noted that the prior art further comprises constructions in which a resonant spring has its ends fundamentally associated with equally movable elements.

One example of this kind of construction is schematically illustrated in figures 4A and 4B, which - respectively - illustrate a block diagram and a schematic cut of a model of a linear compressor that is based in a resonant oscillating mechanism.

Such mechanism fundamentally comprises a resonant spring MR, a passive mass MP, an active mass MA, a fixing block BF, and a shell C. Conventionally, it is also provided structural elements SI1 and SI2 which enable the appropriate functioning of the resonant spring M.

According to the traditional concretizations of the current prior art, the active mass MA is fundamentally composed of a piston P and its respective connecting rod, while the passive mass MP is fundamentally composed of a linear engine (herein including the movable part M1 and the fixed part M2 of the cited linear engine).

The large differential of such mechanism is directed to the utilization of the resonant spring MR, which has a neutral point M' (whose shift is a low-amplitude shift) and two movable ends (capable of presenting complementary shifts). In this sense, one of the ends of the resonant spring MR is fundamentally associated with the passive mass MP, while the other end of the resonant spring MR is fundamentally associated with the active mass MA. The neutral point M' of the resonant spring MR is connected to the shell of the compressor. Normally, the passive mass MP is composed of a linear engine, and the active mass MA is composed of a piston that is capable of being shifted, in a linear and oscillatory manner, in the interior of a cylinder belonging to the head CB of the compressor.

According to the functional principle of such mechanism, the engine imposes motion to its respective end of the resonant spring MR. This motion is transmitted to the opposed end of the resonant spring MR and, consequently, to the active mass MA which effectuates the compression work of the working fluid of the linear compressor.

Considering the existence of resonant resilient forces actuating on the ends of the resonant spring MR, the motion of one of its ends causes the easier motion of the other end, and, consequently, it is necessary a lower amount of energy so as to operate the compressor at its maximum capacity.

One example of linear compressor that is based on a resonant oscillating mechanism is described in the patent application BR 0601645.

However, the full resonant functioning of such mechanisms (functioning whose conditions of opposed mass portions enable a better relation between efficiency and consumed electrical power) can be obtained by a complex way. One of the determinant factors is directed to the balance of the passive and active mass portions of the compressor, and, said balance, per se, is difficult to be implemented.

Besides the balance of the mass portions, it is also considered the reactions which each one of said mass portions presents during the functioning of the compressor. For example, the piston friction with the compression cylinder tends to generate larger effects on the active mass than on the passive mass. On the other hand, eventual electrical anomalies tend to generate larger effects on the passive mass than on the active mass.

Moreover, it is further noted that the capacity of a linear compressor that is based on a resonant oscillating mechanism, as previously described, is mainly related to the shift course of the piston in the interior of the cylinder (available volume for the compression of a working fluid), and the shift course of the piston is proportional to the length of the entire compressor; therefore, the optimization of the capacity of a linear compressor that is based on a resonant oscillating mechanism is also limited by its length.

Anyway, the prior art linear compressors that are based on resonant oscillating mechanisms have some aspects which are still susceptible of functional optimization, and this is the scenario in which the present invention is involved.

Objectives of the Invention

Thus, it is one of the objectives of the present invention the disclosure of a linear compressor that is based on a resonant oscillating mechanism whose mass portions, which are functionally associated with the ends of the resonant spring, present extremely similar features.

Consequently, it is also another objective of the invention the fact that such mass portions present similar reactions during the functioning of the compressor.

It is still another objective of the present invention the provision of a linear compressor that is based on a resonant oscillating mechanism whose optimization of its capacity (over the prior art linear compressors) does not exclusively depend on the increase of its length.

Besides the balance of mass portions, it is also considered the reactions which each one of said mass portions presents during the functioning of the compressor. For example, the piston friction with the compression cylinder tends to generate larger effects on the active mass than on the passive mass. On the other hand, eventual electrical anomalies tend to generate larger effects on the passive mass than on the active mass.

Consequently, it is one of the objectives of the present invention the disclosure of a compressor having a capacity that is similar to the capacity of the prior art compressors, but half-sized.

Summary of the Invention These and other objectives of the instantly revealed invention are totally achieved by a linear compressor which is based on the instantly defined resonant oscillating mechanism.

Said linear compressor comprises at least one resonant spring (placed in the interior of at least one shell), at least two compression assemblies, and at least two heads. The large differential of the present linear compressor addresses in the fact that the same further provides at least two active mass portions which are kept in balance one with the other, and in balance with the resonant spring.

Such active mass portions, which are synchronously operational in accordance with the anti-phase that is established by the resonant spring, are composed of at least one piston (5) and at least one movable part (61 ) of at least one linear engine. In this sense, each piston is capable of reproducing a linear oscillating motion in the interior of its corresponding cylinder by the linear motion imposed by its respective linear engine.

According to the concepts of the present invention, the present linear compressor provides two active mass portions, each one being functionally attached to one of the distal ends of the resonant spring. Preferably, this functional attachment between one active mass and its respective distal end of the resonant spring occurs by the connection of the movable part of the linear engine of the active mass to said distal end of the resonant spring, and, in especial, the connection of the movable part of the linear engine of the active mass to the distal end of the resonant spring occurs by utilizing at least one flat spring.

It is further noted that, generally, the piston and the linear engine, which belong to the same active mass, are directly attached to the movable part of the linear engine. Optionally, said piston is directly attached to the linear motor by using a rod.

Short Description of the Drawings

The present invention will be particularly detailed with basis on the following figures:

Figures 1A, 1 B, 2A, 2B, 3A, 3B, 4A, and 4B, as previously described, represent oscillating mechanisms that are conventionally applied to the prior art linear compressors;

Figure 5A illustrates, in an schematic way, the fundamental block diagram of the instantly defined resonant oscillating mechanism; and

Figure 5B illustrates a cross section of the linear compressor, in accordance with the preferable embodiment of the present invention.

Detailed Description of the Invention

As previously described, conventional linear compressors that are based on a resonant oscillating mechanisms are fundamentally composed of a "active mass" and a "passive mass", wherein each one is placed in one of the distal ends of a resonant spring.

According to the conventional and functional principle, both "active mass" and "passive mass" effectuate the oscillating linear motion; however, only the "active mass" is capable of converting the energy of the system into work, i.e. only the oscillating linear motion of the "active mass" can be converted into an actual compression of a working fluid of the linear compressor. On the other hand, the oscillating linear motion of the "passive mass" has the simple objective of balancing the resonant forces of the "system".

Still considering the above-mentioned composition (related to the current prior art), it is noted that the conventional "active mass portions" are fundamentally composed of a compression piston, while the conventional "passive mass portions" are conventionally composed of a linear engine (or a movable part of the linear engine).

Thus, in this sense, it is involved the present invention, since it reveals a linear compressor that is based on a resonant oscillating mechanism and free of any type of "passive mass". Thus, and in order to render the instantly linear compressor functional, its resonant oscillating mechanism is composed of two active mass portions 1 , wherein each one is placed in one of the distal ends of the resonant spring 2.

In this sense, and in accordance with the definitions of the present invention, each one of the active mass portions 1 is converted into an actual compression of the working fluid of the instantly revealed linear compressor.

Therefore, the present invention reveals a linear compressor comprising two "compression assemblies", being each one of said assemblies defined by one of the active mass portions 1 and its respective working head 3, which includes at least one cylinder 4 and all elements that conventionally exist in heads of compressors, such as, for example, a valve plate, a suction valve, a discharge valve, and the like.

Considering the functional point of view, each one of the active mass portions 1 , according to the present invention, comprises not only the piston (as usually established in the prior art linear compressors), but also an assembly formed by the connection of a piston 5 to the movable part 61 of a linear engine (which further includes a fixed part 62). Preferably, such connection is effectuated by utilizing a connecting rod 11.

Consequently, each one of the distal ends of the resonant spring 2 is functionally attached to an assembly of piston 5 and movable part 61 of a linear engine.

Thus, and in accordance with the intrinsic functional principle of the "resonant spring-mass systems", the active mass portions 1 (assembly of a piston 5 and a movable part 61 of a linear engine) have its actuation synchronized in accordance with the antiphase that is established by the resonant spring 2, i.e. each one of the pistons 5, although physically independents, achieves its superior dead point (maximum progress in relation to the length of the cylinder 4) simultaneously and, consequently, achieve its lower dead point (maximum return in relation to the length of the cylinder 4).

As a consequence of the novel design, the linear compressor achieves two main objectives: the minimization of the imbalance between the functional components of the resonant oscillating mechanism and the duplication of capacity of the linear compressor without severe modifications in relation to the size of its fundamental structure.

The virtually identical balance between the functional components (in especial, between the mass portions that are placed in the distal ends of the resonant spring) occurs by the fact that both active mass portions 1 , in accordance with the present invention, are similar and, therefore, present virtually identical reactions which are caused by the same motivation. For example, both active mass portions 1 are subjected to the same friction forces (mainly originated by the friction of the piston 5 when shifted in the interior of its respective cylinder 4). Moreover, both active mass portions 1 , due to the fact the each includes one linear engine, present virtually identical behavior when occurs nay type of electrical anomaly originated by the feed source of the linear compressor.

The duplication of the linear compressor occurs due to obvious reasons, since the instantly revealed linear compressor is composed of two "compression assemblies", which are placed in the interior of an external shell 7 with sizes (length and diameter) that are substantially similar to the sizes of the shells of the conventional compressors of "half- capacity". Thus, the instantly disclosed linear compressor can be miniaturized with the maintenance of its capacity.

According to figure 5B, it is noted that the linear compressor provides, besides its above-cited fundamental elements, means for damping the impact, axial springs 91 and radial springs 92.

Said means of damping the impact are arranged next to the working heads 3, so as to prevent that the impacts caused by the compression of the working fluid are transmitted to the other elements that compose the linear compressor.

The axial springs 81 has the objective of anchoring the resonant spring 2 in the interior of the external shell 7, optimizing the stability of the movable elements in the interior of the shell 7, which is rigid. The flat springs 92 has the objective of guaranteeing the radial alignment of the active mass portions 1 , besides being used for the attachment between said active mass portions 1 and its respective ends of the resonant spring 2.

In this sense, it is important to detach that these elements do not intend to limit the present invention. Additionally, all these elements are broadly described in the current prior art.

It is noted that all functional components of the linear compressor are placed in the interior of an external shell 7. The resonant spring 2 is fixed to the interior of the shell 7 by its neutral point 21 , by using the axial spring 91 and flat springs 92. Each one of the heads 3 is fixed to one of the distal ends of the shell 7.

Still in accordance with figure 5B, it is noted that each active mass 1 is attached to one of the distal ends of the resonant spring 2 by flat springs 92, wherein, in fact, the movable part of each one of the linear engines 61 is attached to its respective end of the resonant spring 2.

It is further noted that each piston 5 is directly attached to the movable part of its respective linear engine 61 by using a semi-flexible rod 11.

Moreover, it is noted that the cylinder 4 is attached to the shell 7, being placed in the interior of the area that is defined by the movable part 61 of the linear engine. The piston 5 is capable of being reciprocally shifted in the interior of the cylinder 4, and it comprises a fundamentally cylindrical and tubular body, having one of its ends (working end) closed.

As the main concept and at least one preferable concretization of the present invention have already been described, it shall be understood that the scope of the same includes other possible variations, which are only limited by the content of the claims, therein included the equivalent means.

Claims

1. A linear compressor based on a resonant oscillating mechanism comprising at least one resonant spring (2) which is placed in the interior of at least one shell (7), at least two compression assemblies, and at least two heads (3) CHARACTERIZED in that it comprises:

at least two active mass portions (1 ) which are kept in balance one with the other, and in balance with the resonant spring (2);

said active mass portions (1 ) being synchronously operational in accordance with the anti-phase that is established by the resonant spring (2);

each active mass (1 ) being composed of at least one piston (5) and at least one movable part (61 ) of at least one linear engine; and

each piston (5) being capable of reproducing a linear oscillating motion in the interior of its corresponding cylinder (4) by the linear motion imposed by its respective movable part (61 ) of its linear engine.

2. A linear compressor, in accordance with Claiml , CHARACTERIZED in that it provides two active mass portions (1 ), each one being functionally attached to one of the distal ends of the resonant spring (2).

3. A linear compressor, in accordance with Claim 1 or 2, CHARACTRIZED in that such functional attachment between one active mass (1 ) and its respective distal end of the resonant spring (2) occurs by connecting the movable part (61 ) of the linear engine of the active mass (1 ) to said distal end of the resonant spring (2).

4. A linear compressor, in accordance with Claim 3, CHARACTERIZED in that the connection of the movable part (61 ) of the linear engine of the active mass (1 ) to the distal end of the resonant spring (2) occurs by utilizing at least one flat spring (92).

5. A linear compressor, in accordance with Claim , CHARACTERIZED in that the piston (5) and the movable portion (61 ) of the linear engine, which belong to the same active mass (1 ), are directly attached one to the other.

6. A linear compressor, in accordance with Claim 1 , CHARACTERIZED in that said piston (5) is directly attached to the movable portion (61 ) of the linear engine.

7. A linear compressor, in accordance with Claim 5 or 6, CHARACTERIZED in that said piston (5) is directly attached to the movable part (61 ) of the linear engine by using a rod (11 ).