LINEAR MOTOR, COOLING EQUIPMENT COMPRESSOR, COOLING EQUIPMENT AND STATOR APPLICABLE IN A LINEAR MOTOR

Abstract

A linear motor (1) including: a stator (2) defining at least an air gap area (10), at least one coil (3) associated to the stator (2), wherein a magnetic flow moves over at least one portion of the stator (2) and over a portion of the air gap area (10), wherein the linear motor (1) includes a magnetic body (5) disposed in the air gap area (10), wherein a movement parameter of the magnetic body (5) in the air gap area (10) causes movement of a piston (7) of the linear motor (1), wherein the linear motor (1) further includes: at least one magnetically permeable element (20, 20A, 20B) disposed in the air gap area (10) and adjacently to the magnetic body (5), wherein the movement parameter of the magnetic body (5) is cooperative to the movement parameter of the magnetically permeable element (20, 20A, 20B). A compressor, cooling equipment and stator (2) applicable in a linear motor are also described.

Claims

1. A linear motor (1) comprising: a stator (2) defining at least an air gap area (10); at least one coil (3) associated to the stator (2), wherein a magnetic flow (4) moves over at least one portion of the stator (2) and over a portion of the air gap area (10); wherein the linear motor (1) comprises a magnetic body (5) disposed in the air gap area (10); wherein a movement parameter of the magnetic body (5) in the air gap area (10) causes movement of a piston (7) of the linear motor (1); wherein the linear motor (1) further comprises: at least one magnetically permeable element (20) disposed in the air gap area (10) and adjacently to the magnetic body (5), wherein the movement parameter of the magnetic body (5) is cooperative to the movement parameter of the magnetically permeable element (20).

2. The linear motor (1) according to claim 1, wherein the magnetically permeable element (20) is formed by a first segment (20A) and by a second segment (20B).

3. The linear motor (1) according to claim 2, wherein the first segment (20A) and the second segment (20B) are disposed at opposite ends of the magnetic body (5).

4. The linear motor (1) according to claim 3, wherein the first segment (20A) is formed by a first magnetically permeable material and the second segment (20B) is formed by a second magnetically permeable material.

5. The linear motor (1) according to claim 4, wherein the first magnetically permeable material and the second magnetically permeable material are ferromagnetic materials.

6. The linear motor (1) according to claim 5, wherein at least one of the first magnetically permeable material and the second magnetically permeable material is iron.

7. The linear motor (1) according to claim 5, wherein at least one of the first segment (20A) and the second segment (20B) is formed by a plurality of steel blades (25) sequentially arranged along the magnetically permeable element (20).

8. The linear motor (1) according to claim 6, wherein a first distance (D.sub.1) of the magnetically permeable element (20) to the magnetic body (5) is equal to or less than a thickness (E) of the magnetic body (5).

9. The linear motor (1) according to claim 7, wherein a boundary limit (A,A) of the stator (2) is defined by end surfaces (2A,2B) of the stator (2), wherein at an outermost point of the movement parameter of the magnetic body (5), one of the first segment (20A) and the second segment (20B) moves to a point beyond the boundary limit (A,A).

10. The linear motor (1) according to claim 8, wherein while one of the first segment (20A) and the second segment (20B) moves to a point beyond the boundary limit (A), the adjacent segment is mostly disposed in the air gap area (10).

11. The linear motor (1) according to claim 9, wherein at an outermost point of the movement parameter of the magnetic body (5), one of a first surface (5A) and a second surface (5B) of the magnetic body (5) is disposed on one of the boundary limits (A,A) while the opposite surface (5A, 5B) is disposed on an air gap shaft (C,C) of the linear motor (1).

12. The linear motor (11) according to claim 11, wherein the air gap shaft (C,C) is defined by inner surfaces (2C,2C) of the stator (2).

13. The linear motor (1) according to claim 12, wherein the first segment (20A) and the second segment (20B) are dimensionally identical.

14. The linear motor (1) according to claim 12, wherein the first segment (20A) and the second segment (20B) are dimensionally different to each other.

15. The linear motor (1) according to claim 13, wherein each air gap area (10) comprises just one single magnetic body (5).

16. A cooling equipment compressor, comprising a linear motor (1) comprising: a stator (2) defining at least an air gap area (10); at least one coil (3) associated to the stator (2), wherein a magnetic flow (4) moves over at least one portion of the stator (2) and over a portion of the air gap area (10); wherein the linear motor (1) comprises a magnetic body (5) disposed in the air gap area (10); wherein a movement parameter of the magnetic body (5) in the air gap area (10) causes movement of a piston (7) of the linear motor (1); said linear motor (1) further comprising at least one magnetically permeable element (20) disposed in the air gap area (10) and adjacently to the magnetic body (5), wherein the movement parameter of the magnetic body (5) is cooperative to the movement parameter of the magnetically permeable element (20).

17. The cooling equipment compressor as set forth in claim 16, provided in one of: (i) refrigerator; (ii) freezer; air-conditioning equipment.

18. A stator (2) applicable in a linear motor (1), the stator (2) defining at least an air gap area (10) and further comprising at least one coil (3) associated to the stator (2), wherein a magnetic flow (4) moves over at least one portion of the stator (2) and over a portion of the air gap area (10), wherein the stator (2) comprises a magnetic body (5) disposed in the air gap area (10), wherein the stator (2) further comprises: at least one magnetically permeable element (20) disposed in the air gap area (10) and adjacently to the magnetic body (5), wherein a movement parameter of the magnetic body (5) in the air gap area (10) is cooperative to the movement parameter of the magnetically permeable element (20).

19. The linear motor (1) according to claim 7, wherein a first distance (D.sub.1) of the magnetically permeable element (20) to the magnetic body (5) is equal to or less than a thickness (E) of the magnetic body (5).

20. The linear motor (1) according to claim 14, wherein each air gap area (10) comprises just one single magnetic body (5).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will now be described in greater detail based on an example of an embodiment represented in the drawings. The drawings show:

[0028] FIG. 1illustrates a linear compressor capable of receiving a linear motor as proposed in the present invention;

[0029] FIG. 2illustrates a topology of a linear motor known in the state of the art, also highlighting a movement parameter of the magnetic body through the air gap area, wherein FIG. 2(a) illustrates the magnetic body at its maximum displacement adjacent to one of the boundary limits of the stator, FIG. 2 (b) illustrates the magnetic body at its intermediary displacement and FIG. 2(c) illustrates the magnetic body at its maximum displacement, opposite the displacement represented in FIG. 2(a).

[0030] FIG. 3illustrates an additional topology of a linear motor known in the state of the art and which will be able to absorb the teachings of the present invention;

[0031] FIG. 4represents an additional topology of a linear motor known in the state of the art and able to absorb the teachings of the present invention, further representing the displacement of the magnets in the air gap area and also the boundary limits of the stator, wherein FIG. 4(a) represents the maximum displacement of the magnets as far as one of the boundary limits, FIG. 4(b) represents an intermediary displacement of the magnets and FIG. 4(c) represents the maximum displacement of the magnets as far as the boundary limit opposite that represented in FIG. 4(a);

[0032] FIG. 5illustrates a topology of a linear motor comprising the teachings proposed in the present invention, wherein the linear motor comprises a magnetically permeable movement element cooperative to the movement of the magnetic body, wherein FIGS. 5(a) and 5(b) illustrate the linear motor where the displacement of the magnet reached its outermost limits, and FIG. 5(c) illustrates the linear motor wherein the displacement of the magnet is at an intermediary point of the representation of FIGS. 5(a) and 5(c);

[0033] FIG. 6illustrates a topology of a linear motor comprising the teachings proposed in the present invention, wherein each segment of the magnetically permeable element comprises a certain sizing, such that FIGS. 6(a) and 6(b) illustrate points of maximum displacement of the magnetic body;

[0034] FIG. 7illustrates an additional topology of a linear motor that comprises the teachings proposed in the present invention, wherein the linear motor comprises a magnetically permeable movement element cooperative to the movement of the magnetic body, wherein FIGS. 7(a) and 7(b) illustrate the linear motor wherein the displacement of the magnet reached its outermost limits;

[0035] FIG. 8represents a graph of the magnetic flow variation rate based on the displacement of the magnet for a motor known in the state of the art and for a motor that comprises the teachings proposed in the present invention;

[0036] FIG. 9is a representation of a displacer of a linear motor that comprises the teachings of the present invention, indicating the formation of the magnetically permeable element based on a plurality of steel blades as well as the form of disposition of the magnetically permeable element and of the magnetic body on the displacer.

[0037] FIG. 10is an additional representation of a linear motor that comprises the teachings proposed in the present invention, also highlighting a first distance between the magnetically permeable element and the magnetic body and also a thickness of the magnetic body;

[0038] FIG. 11illustrates an additional representation of the linear motor of FIG. 10, highlighting the disposition of a portion of the second segment of the magnetically permeable element outwardly of the air gap area;

[0039] FIG. 12illustrates an additional representation of the linear motor shown in FIG. 10, indicating a movement parameter opposite that indicated in said figure;

[0040] FIG. 13illustrates an additional representation of the linear motor shown in FIG. 12, highlighting the disposition of a portion of the first segment of the magnetically permeable element outwardly of the air gap area.

DETAILED DESCRIPTION OF THE INVENTION

[0041] The present invention refers to a linear motor 1, and more specifically to a linear motor 1 capable of being used in a linear compressor 30 of a cooling system.

[0042] Cooling system is understood to be any system wherein a certain cooling gas is used to cool/acclimatize a certain environment or product. In this arrangement of the present invention, cooling system can be understood to be cooling equipment (such as a freezer or refrigerator) or air-conditioning equipment.

[0043] FIG. 1 illustrates a linear compressor 30 capable of receiving a linear motor 1 such as proposed in the present invention. The present description will concentrate on the relevant characteristics of the linear compressor 30 for a perfect understanding of the linear motor 1 proposed in the present invention.

[0044] Therefore, and as known by those persons skilled in the art, the linear compressor 30 comprises a cylinder 31, which presents a board of valves at its uppermost end, also called valve head. This board of valves comprises a suction valve 32 that lets gas at low pressure into the cylinder 31, and a discharge gas valve 33 that lets gas at high pressure out of the cylinder 31.

[0045] The linear compressor 30 further comprises a piston 34 that moves inside the cylinder 31, constituting therewith a resonant set. Inside the cylinder 31, the piston 34 carries out an alternative linear movement, performing action of compression on the gas taken inside the cylinder 31 by the suction valve 32, up to the point at which this gas can be discharged to the high pressure side by way of the discharge valve 33.

[0046] It is also noted in FIG. 1 that the piston 34 is coupled to at least one magnetic body 5 (magnet) of a linear motor, such that the displacement of the piston 34 causes a corresponding displacement of the magnet 5, and vice-versa. The magnet 5 is preferably disposed around the outer surface of the piston 34, as can be seen in FIG. 1. In alternative forms, the magnet 5 may be connected to the piston in different ways, for example being fixed to a rod that is connected to the piston. The form of fastening the magnet 5 to the piston 34 does not refer to the essential characteristic of the present invention.

[0047] The linear compressor 30, and more specifically its linear motor 1, further comprises a stator 2 associated to a coil 3, and said coil 3 should be electrically powered so as to produce a magnetic field responsible for operating the linear motor 1. Also noted is an air gap area 10 disposed next to the stator 2 in which said magnetic body 5 should move so as to enable the due operation of the linear motor.

[0048] It is worth emphasizing that FIG. 1 does not effectively illustrate the teachings proposed in the present invention, and this figure is being used solely for an improved understanding of a compressor 30 and of the main elements that form it. As better addressed ahead, the present invention focuses its teachings in the air gap area 10 and on the magnetic body 5 of the linear compressor 30.

[0049] With regards to the magnet 5 of the linear compressor 30, and as already addressed previously, it should move through the air gap area 10 so as to provide the movement of the piston 34 of the compressor 30. Therefore, it is understood that the magnet 5 (magnetic body) establishes a movement parameter in the air gap area 10. In other words, the movement parameter of the magnet 5 should be understood as the movement (displacement) of the magnet 5 in the air gap 10.

[0050] In this sense, FIG. 2 represents a topology of a linear motor known in the state of the art, wherein the stator 2, coil 3, magnet 5 and air gap 10 are illustrated.

[0051] More specifically, FIG. 2 represents the movement parameter of the magnetic body 5 through the gap 10 in a linear motor with U-shaped topology, wherein it is noted that the magnetic body 5 excursions between the boundary limits A and A of the stator 2 (the boundary limits A and A are explicitly illustrated in FIG. 2(a)).

[0052] Accordingly, FIG. 2(a) illustrates the magnetic body 5 at its maximum displacement, adjacent to the boundary limit A, FIG. 2(b) illustrates the magnetic body 5 at its intermediary displacement and FIG. 2(c) illustrates the magnet 5 at its maximum displacement adjacent to the boundary limit A.

[0053] FIG. 3 illustrates an additional topology of a linear motor 1 with U-shaped stator 2, representing an additional form of association of the coils 3 to the stator 2. The air gap area 10 as well as the magnet 5 is seen in this figure.

[0054] FIG. 4 illustrates a topology of a linear motor known in the state of the art as E-shaped topology, said terminology originating from the shape of the stator 2. It is noted in this arrangement that two magnetic bodies 5 and 5 move along the air gap 10. Precisely by having two magnets 5,5 disposed in the air gap 10, this topology ultimately provides a greater magnetic flow variation rate. On the other hand, the manufacturing costs of the motor also increase.

[0055] FIG. 4(a) shows the representation of the boundary limits A, A of the stator 2. It is thus understood that FIG. 4(a) represents the maximum displacement of the magnet 5 as far as the boundary limit A, FIG. 4(b) representing an intermediary displacement of the magnets 5 and 5 and FIG. 4(c) representing the maximum displacement of the magnets 5 and 5, wherein the magnet 5 moves as far as the boundary limit A.

[0056] Therefore, FIGS. 1 to 4 are non-exhaustive representations of compressors and linear motors that can absorb the teachings of the present invention.

[0057] In this sense, FIG. 5 illustrates a representation of a stator 2 of a linear motor 1 comprising the teachings proposed in the present invention.

[0058] The elements previously described when addressing FIGS. 1 to 4 are again presented in the subsequent figures, wherein the same reference number is used. So there is a stator 2, a magnetic body 5 that moves in the air gap 10 as well as a coil 3 associated to the stator 2.

[0059] It is noted that FIG. 5 illustrates a possible topology for a linear motor with a U-shaped stator 2, wherein a single magnet 5 moves in the air gap area 10, that is, between the two legs of the U.

[0060] The teachings of the present invention provide an increase in the magnetic flow variation when compared to the teachings of the state of the art. Accordingly, the disposition of at least one magnetically permeable element 20 in the air gap area 10 is proposed, as shown in FIG. 5.

[0061] Accordingly, it is noted that this arrangement of the present invention proposes the use of two magnetically permeable elements 20, each of them disposed on one of the sides of the magnet 5, as represented in FIG. 5. It is thus understood that the magnetically permeable element 20 is formed by a first segment 20A and by a second segment 20B, each of the segments disposed on the side (adjacently) of one of the sides of the magnet 5. Accordingly, it can be seen in FIG. 5 that the first segment 20A and the second segment 20B are disposed at opposite ends of the magnetic body 5.

[0062] In a preferred and valid arrangement of the present invention, both the first segment 20A and the second segment 20B are made of one and the same material, being iron.

[0063] In other fully valid modalities, the first segment 20A can be made in a first magnetically permeable material and the second segment 20B in a second magnetically permeable material.

[0064] Obviously, it is understood that the first and second magnetically permeable materials should be ones that facilitate the passage of the lines of magnetic flow on the surface of this material.

[0065] In this sense, persons skilled in the art are aware of the fact that the materials can be classified according to their magnetic permeability, that is: diamagnetic materials (have lesser permeability than that of vacuum), paramagnetic materials (have slightly greater permeability than that of vacuum) and ferromagnetic materials (have permeability of hundreds and even thousands of times greater than that of vacuum).

[0066] More specifically, it should be understood the first magnetically permeable material and the second magnetically permeable material as ferromagnetic materials, such as: iron, nickel, steel, cobalt and their respective alloys.

[0067] Therefore, a valid and non-limitative arrangement of the present invention consists of the formation of the first segment 20A made of iron and of the second segment 20B made of nickel.

[0068] A preferred form of fastening the magnetically permeable element 20 in the linear motor 1 is represented in FIG. 9. It is noted that the magnetically permeable element 20 is fastened on the displacer 18 of the linear motor, adjacently to the magnetic body 5.

[0069] Therefore, the displacer 18 acts as a support (mold) for the set formed by the magnetically permeable element 20 and the magnetic body 5. Accordingly, it is understood that during the operation of the linear motor 1, the displacer 18 moves jointly with the magnetically permeable element 20 and the magnetic body 5.

[0070] In one modality, the displacer 18 can be made of aluminum. In any case, this should not be considered as a limitative characteristic of the present invention.

[0071] As known by persons skilled in the art, the displacer 18 of a linear motor 1 should be understood as the active part of the motor, equivalent to the rotor (mobile part) of a conventional motor.

[0072] Additionally, a fully valid arrangement of the present invention proposes that the magnetically permeable element 20 is formed by a plurality of steel blades 25, like the steel blades 25 used in manufacturing electric motors. Further, it is proposed that the steel blades 25 are sequentially arranged along the element 20, such as represented in FIG. 9.

[0073] Therefore, the disposition of the magnetically permeable element 20 as proposed herein decreases the resistance of the magnetic flow lines which move through the air gap 10, in other words, the magnetically permeable element 20 will make the flow lines be attracted, whereby boosting the magnetic flow variation, as illustrated in the graph of FIG. 8, wherein the magnetic flow variation rate based on the displacement of the magnet 5 is illustrated. Amounts obtained by simulation are thus highlighted for motors that do not make use of the magnetically permeable element 20 and for motors according to the teachings of the present invention.

[0074] Based on the teachings of the present invention, that is, with the disposition of the magnetically permeable element 20, there is obtained a magnetic flow variation rate similar to the one obtained with the linear motor that comprises a pair of magnets in its air gap 10 (such as the motor illustrated in FIG. 4). However, it is emphasized that the arrangement shown in FIG. 5 makes use of just one single magnetic body 5.

[0075] It is thus understood that the teachings of the present invention are preferably beneficial for the linear motor that comprises U-shaped topology, and which thus makes use of just one magnetic body in its air gap.

[0076] According to the teachings of the present invention and as illustrated in FIG. 5, a movement of the magnet 5 will also cause the movement of the magnetically permeable element 20 (and consequently of the segments 20A and 20B), it is thus understood that the movement parameter of the magnetic body 5 is cooperative to the movement parameter of the magnetically permeable element 20.

[0077] In other words, and taking the representation of FIG. 5 as reference, as the magnet 5 moves to the left, the magnetically permeable element 20 (and segments 20A and 20B) will also move to the left. Similarly, as the magnet 5 moves to the right, the magnetically permeable element 20 will also move to the right.

[0078] Therefore, and considering the illustration in FIG. 5 (a) wherein the boundary limit A and A of the stator 2 is defined respectively by the end surfaces 2A and 2B thereof, then at an outermost point of the movement parameter of the magnetic body 5 the first segment 20A of the magnetically permeable element 20 moves beyond the boundary limit A.

[0079] In this situation, the adjacent segment, that is, the second segment 20B of the magnetically permeable element 20 is mostly disposed in the air gap area 10, that is, the second segment 20B is mostly disposed in the region defined by the boundary limits A and A.

[0080] By mostly disposed, it is understood that the second segment 20B will have its outer wall 21 disposed exactly on the boundary limit A, such as represented in FIG. 10, or even a minority portion (less than 50% of its length) of the second segment 20B will be disposed beyond the boundary limit A, that is, disposed outside the area defined by the boundary limit A, as represented in FIG. 11.

[0081] The outermost point of the movement parameter of the magnetic body 5 is understood to mean the maximum displacement of the magnet 5 before its change of direction, such as the situation represented in FIGS. 5(a) and 5(b).

[0082] In line with that previously described for FIG. 5(a), FIG. 5(b) illustrates the movement parameter of the magnet 5 wherein at the outermost point of said displacement the second segment 20B moves to a point beyond the boundary limit A while the first segment 20A is mostly disposed in the air gap area 10.

[0083] By mostly disposed, it is understood that the first segment 20A will have its outer wall 21 disposed exactly on the boundary limit A, such as represented in FIG. 12, or even that a minority portion (less than 50% of its length) of the first segment 20A will be disposed beyond the boundary limit A, that is, disposed outside the area defined by the boundary limit A, as represented in FIG. 13.

[0084] Further in relation to the sizing of the magnetic body 5, it is proposed that at the outermost point of the movement parameter of the magnet 5, a first surface 5A of the magnetic body will be disposed on the boundary limit A, whereas a second surface 5B is disposed on an air gap shaft C, as shown in FIG. 5 (a).

[0085] In accordance with the description set out in the preceding paragraph, at the point opposite that represented in FIG. 5 (a), the second surface 5B of the magnetic body is disposed on the boundary limit A, whereas the first surface 5A (opposite the second surface 5B) is disposed on the air gap shaft C of the linear motor 1, as represented in FIG. 5 (b).

[0086] It is thus understood that each one of the air gap shafts C and C of the linear motor 1 is respectively defined by inner surfaces 2C and 2C of the stator 2, as represented in FIGS. 5 (a) and 5 (b).

[0087] In addition to the representation of FIGS. 5(a) and 5(b), FIG. 5(c) illustrates the scenario wherein the displacement of the magnet 5 is found at an intermediary point to the scenario represented in FIGS. 5(a) and 5(b).

[0088] Further in relation to the sizing of the magnetically permeable element 20 and of the magnetic body 5, and with specific reference to FIG. 10, a first distance D1 of the magnetically permeable element 20 as far as the magnet 5 is preferably of the order of a thickness E of the magnet or less.

[0089] In other words, it is understood that the first distance D1 is equal to or less than thickness E of the magnet 5, according to representation 11. Therefore, it is understood that D1E.

[0090] As represented in FIG. 5, this arrangement of the present invention proposes that the first and second segments 20A and 20B have equal dimensions, that is, said segments are dimensionally identical. In any way, the arrangement of a linear motor is fully valid, wherein segments 20A or 20B have different sizes to each other.

[0091] Therefore, FIG. 6 illustrates a modality wherein the second segment 20B has a length L greater than the length of the first segment 20A. Obviously it is understood that the reverse scenario is also fully acceptable. With this proposal, the manufacturer of the linear motor 1 has the possibility of sizing each one of the segments 20A and 20B according to the material used in the manufacture thereof. Further in relation to FIG. 6, it is noted that the FIGS. 6(a) and 6(b) illustrate maximum displacement points of the magnet 5. The difference commented upon in relation to length L of segments 20A and 20B should not represent a limitation of the present invention, such that thickness E of the magnetically permeable element 20 could also be dimensionally different to each other.

[0092] Obviously, applying the present invention is not limited to the stator 2 represented in FIGS. 5, 6, 7 and 10 to 13, such that it is understood that the use of the magnetically permeable element 20 is possible in any topology known for a linear motor, and not only for those discussed and illustrated in the present invention.

[0093] Whatever the topology of the linear motor, it is understood to be fully possible to apply the modality wherein the segments 20A and 20B have equal or different sizing, as already addressed herein.

[0094] There is thus described a linear motor 1 endowed with a magnetically permeable element 20, wherein the movement parameter of the magnetically permeable element 20 is cooperative to the movement parameter of the magnetic body 5 (magnet) of the linear motor 1.

[0095] The teachings of the present invention provide an increase in the magnetic flow variation that circulates through the stator 2 and air gap 10, providing, for example, that a linear motor endowed with a single magnetic body has a similar flow variation rate to a motor that comprises a pair of magnets.

[0096] In harmony with that previously described, the present invention further addresses a compressor endowed with a linear motor 1 according to the teachings of the present invention. In one modality, said compressor is used in cooling equipment, such as a freezer/refrigerator or air-conditioning equipment.

[0097] Therefore, the present invention further proposes cooling equipment that comprises the linear motor defined herein.

[0098] In harmony with the description previously set out, a stator 2 applicable to a linear motor 1 is also proposed.

[0099] Lastly, the arrangement of the present invention wherein the magnetically permeable element 20 is made of Sheet Molding Compound (SMC) is fully valid.

[0100] Having described one example of a preferred embodiment, it should be understood that the scope of the present invention covers other possible variations, being limited solely by the content of the accompanying claims, potential equivalents being included therein.