Linear compressor with linear electric motor and household appliance

Abstract

The invention relates to a linear compressor with a linear electric motor and a household appliance. Disclosed is a linear compressor for a household appliance (e.g., a refrigerator) in which a yoke-magnet arrangement is clamped on a cylinder of a cylinder-piston arrangement in a manner that enables temperature expansion of the yoke-magnet arrangement; in particular by forcing the yoke-magnet arrangement against a fixed stop of the cylinder via a spring force. The invention further discloses a household appliance.

Description

Technical Field

[0001] The present invention relates to a linear compressor for a household appliance and a household appliance having a linear electric motor, the linear electric motor including a stator having coils and a movable system. Background Technology

[0002] Several linear compressors with linear electric motors are known from the prior art. US8876497B2 discloses a linear compressor comprising: a cylinder having a compression space for a refrigerant; a piston that performs a linear reciprocating motion in the axial direction within the cylinder to compress the refrigerant; and a frame having mounting holes allowing one end of the cylinder to be mounted on the frame, and having anti-deformation portions in a portion surrounding the mounting holes contacting this end of the cylinder. Even with an increase in cylinder size and a limitation on frame size, the frame achieves sufficient strength to support the cylinder, thereby reducing installation deformation and improving operational reliability. One disadvantage of this linear compressor is that it is subjected to severe temperature changes due to refrigerant compression, which can damage the moving parts of the linear compressor. This can shorten the service life of the linear compressor. Summary of the Invention

[0003] Therefore, the problem of the present invention is to provide a linear compressor with a linear electric motor and a household appliance with a reliable compressor, wherein the linear electric motor ensures reliable operation even under drastic temperature changes.

[0004] This problem is solved by a linear compressor having the features of claim 1 and by using a household appliance according to claim 11.

[0005] This invention relates to a linear compressor for a household appliance, the linear compressor having a linear electric motor comprising a stator with coils and a movable system (mover). The movable system is movable in an axial direction. It includes a yoke-magnet arrangement, a cylinder, and a spring. The yoke-magnet arrangement has an annular yoke arranged on the cylinder and carrying a magnetic ring. The spring-loaded yoke-magnet arrangement presses against a fixed stop on the cylinder, restricting axial movement of the yoke-magnet arrangement on the cylinder on one side. The yoke has a shoulder facing the fixed stop and restricting axial movement of the magnetic ring on the yoke on the other side.

[0006] Compared to conventional compressors, the cylinders of linear compressors can move along a linear path to minimize friction and reduce energy loss during motion transitions. This technology has been successfully used in cryogenic applications, which can be oil-free. Therefore, linear compressors with valves enable the use of compact heat exchangers. Linear compressors can be connected to alternating current, for example, by means of a diode. The cylinder can be spring-loaded and moved relative to a fixed piston by means of a mover driven by a linear electric motor. During a positive cycle of alternating current, the diode allows current to flow through the stator's electromagnet and generates a magnetic field that acts on the mover and thus moves the cylinder backward away from the piston, compressing the spring and thus creating an attractive force that draws the gaseous medium or coolant into the compression chamber. During a negative cycle of alternating current, the diode can block current flow to the stator's electromagnet, thereby relaxing the spring, moving the piston forward, and compressing the refrigerant. The compressed refrigerant can then be discharged via a valve to achieve the desired cooling effect. Preferably, the coil has a cylindrical shape. The magnetic ring can be a permanent magnet. A yoke is used to distribute the magnetic field, thereby amplifying the driving force of the linear electric motor.

[0007] Preferred household appliances include a linear compressor according to the invention. An exemplary household appliance is a refrigerator.

[0008] If the spring acts directly on the yoke, the number of parts is reduced and the system's response behavior is optimized.

[0009] Preferably, the spring is a ring and has a wavy shape. This allows for a compact design. Alternatively, a helical spring or a disc spring is preferred.

[0010] Alternatively, the spring can be a retaining ring arranged in a cylinder recess. This allows for a technically simple and reliable arrangement of the spring.

[0011] Alternatively, the spring is a ring, which is held in place on the cylinder by an insert that surrounds the cylinder and acts as a spring support. This eliminates the need for a recess in the cylinder. Furthermore, the insert can help center the ring on the cylinder.

[0012] In one embodiment, the yoke is divided into two annular yoke portions, each annular yoke portion having a shoulder for limiting the axial movement of the magnetic ring. By means of this, the magnetic ring is axially fixed by the two opposing yoke shoulders.

[0013] To prevent any axial movement of the magnetic ring on the yoke, the axial extension of the receiving area for the magnetic ring is smaller than the axial extension of the magnetic ring.

[0014] In another embodiment, the yoke has a tubular section for receiving the magnetic ring, wherein the axial extension of the tubular section is smaller than the axial extension of the magnetic ring. By means of this, only one shoulder for the magnetic ring is provided by the yoke. The second shoulder is a non-movable stop for the cylinder.

[0015] In another embodiment, the yoke has a tubular section with axial protrusions at its front. These protrusions are adapted to pass between radial protrusions of the cylinder, which are spaced apart from each other in the circumferential direction and form immovable stops for the cylinder. This prevents rotation of the yoke on the cylinder.

[0016] To prevent any axial movement of the magnetic ring on the yoke, the tubular section for receiving the magnetic ring has an axial extension smaller than the axial extension of the magnetic ring. Attached Figure Description

[0017] In the following explanation, preferred embodiments of the invention are illustrated with reference to the accompanying drawings. As will be understood, various elements and components are depicted only as examples, and they may be combined in arbitrary and / or different ways than those depicted. Reference numerals for related elements are used collectively and are not redefined for each drawing. The following are illustrated schematically:

[0018] Figure 1 This is a schematic representation of a linear compressor with a linear electric motor;

[0019] Figures 2a to 2d It comes from Figure 1 An enlarged view of a first embodiment of the yoke-magnet arrangement structure of a linear compressor;

[0020] Figures 3a to 3d It comes from Figure 1 An enlarged view of a second embodiment of the yoke-magnet arrangement structure of a linear compressor;

[0021] Figures 4a to 4d It comes from Figure 1 An enlarged view of a third embodiment of the yoke-magnet arrangement structure of a linear compressor; and

[0022] Figures 5a to 5d It comes from Figure 1 An enlarged view of the fourth embodiment of the yoke-magnet arrangement structure of the linear compressor. Detailed Implementation

[0023] Figure 1 A schematic representation of a linear compressor 1 with a linear electric motor is shown. A preferred household appliance with such a linear compressor is a refrigerator.

[0024] The linear electric motor includes a stator 2 with coils 3 and a movable system (mover) 4. The movable system 4 is movable in the axial direction x. It includes a yoke-magnet arrangement (5, 6), a cylinder 7, and a spring 8.

[0025] The yoke-magnet arrangement structure includes an annular yoke 6 arranged on the cylinder 7 and a magnetic ring 5. The magnetic ring 5 is positioned on the yoke 6 and generates a magnetic field. The magnetic ring 5 is a permanent magnet.

[0026] Spring 8 presses against the immovable stop 9 on cylinder 7 and restricts the axial movement of the yoke-magnet arrangement on cylinder 7 on one side (right side according to the diagram).

[0027] exist Figure 1 In the first embodiment shown, the spring 8 is an open retaining ring with a wavy shape and is arranged in an annular groove 10 in the outer surface of the cylinder 7. However, as Figures 5a to 5b As shown, the spring 8 can also be a closed wave ring, which is held in place by the insert 11 that surrounds the cylinder 7 and acts as a spring support.

[0028] The yoke 6 has a (reverse) shoulder 16 that faces the immovable stop 11 and restricts the axial movement of the magnetic ring 5 on the yoke 6 on the other side (left side according to the illustration).

[0029] The piston 12 is arranged inside the cylinder 7, thereby compressing the gas medium or coolant in the chamber 13 between the piston 12 and the cylinder 7 by the oscillating movement of the cylinder 7 relative to the stationary piston 12.

[0030] refer to Figures 2a-2d , Figures 3a-3d , Figures 4a-4d and Figures 5a-5d The preferred embodiment with circled area 14 is explained in detail.

[0031] according to Figure 1 , Figures 2a to 2dIn a first embodiment of the movable system 4 shown, the yoke-magnet arrangement includes a yoke 6 divided into two portions 6a and 6b along a vertical plane z. The yoke portions 6a and 6b are symmetrical with respect to the vertical plane z. Both include tubular sections 18 and 20 for receiving a magnetic ring 7, and radially outer shoulders 16 and 22 for axially positioning the magnetic ring 5 on the tubular sections 18 and 20. If the annular yoke portions 6a and 6b are placed together, the axial extension of the receiving area formed by the two tubular sections 18 and 20 for the magnetic ring 5 is smaller than the axial extension of the magnetic ring 5. For example, a gap 24 can be provided between the yoke portions 6a and 6b for tolerance compensation of the yoke portions 6a and 6b and the magnetic ring 5. To avoid any negative impact on the electromagnetic field distribution, the gap 24 between the yoke portions 6a and 6b is minimized as much as possible, while the tolerance compensation of the yoke-magnet arrangement remains unchanged.

[0032] The cylinder 7 has a radially outer shoulder forming a non-movable stop 19. An annular groove 10 suitable for receiving the spring 8 is provided in the cylinder 7 at an axial distance from the non-movable stop 9.

[0033] Spring 8 is a waveform retaining ring adapted to be inserted into an annular groove 10.

[0034] The axial distance between the immovable stop 9 and the groove 10 allows for the balance of thermal expansion of the yoke arrangement and / or the cylinder 7. The immovable stop 9 of the cylinder 7 defines a rigid shoulder in the right direction, while the yoke-magnet arrangement can expand slightly to the left due to the release of the elastic anti-stop by the spring 8, thus avoiding thermal stress. Therefore, when the spring 8 forces the yoke-magnet arrangement against the immovable stop 9, the yoke-magnet arrangement always has a defined axial position.

[0035] In the assembled state, the magnetic ring 5 is positioned on the tubular sections 18 and 20 of the yoke portions 6a and 6b and is held between their shoulders 16 and 22. The yoke portions 6a and 6b are held between the immovable stop 9 and the retaining ring 8 (spring). Thus, due to the retaining ring 8 (spring), the yoke-magnet arrangement structure (5, 6a, 6b) can move slightly in the axial direction x, which allows for, for example, tolerance compensation due to temperature changes.

[0036] In other words, the first embodiment has a single wave retaining ring as spring 8 and two symmetrical and equal yoke portions 6a, 6, which extend axially over the magnetic ring 5 in their assembled state. The wave retaining ring 8 is supported against the groove wall 26 and is subjected to axial pressure in the direction to the immovable stop 9 (particularly against the first yoke portion 6a, from the first yoke portion 6a to the magnetic ring 5, via the magnetic ring 5 to the second yoke portion 6b and via the second yoke portion 6b to the immovable stop 9).

[0037] according to Figures 3a to 3d In a second embodiment of the movable system 4 shown, the yoke-magnet arrangement includes a single-piece yoke 6. The yoke 6 has a tubular section for receiving a magnetic ring 5 and a radially outer shoulder 16 for limiting axial movement of the magnetic ring 5 to the left side on the tubular section 18. The axial extension of the receiving area formed by the tubular section 18 for the magnetic ring 5 is smaller than the axial extension of the magnetic ring 5, such that a gap 24 is established between the immovable stop 9 and the yoke 6 in the assembled state.

[0038] The cylinder 7 also has an annular groove 10 for receiving the spring 8, which in this embodiment is also a retaining ring.

[0039] In the assembled state, the magnetic ring 5 is positioned on the tubular section 18 and held between the immovable stop 9 of the cylinder 7 and the spring 8 (retaining ring) in the groove 10. As a result, due to the retaining ring 7 (spring), the yoke-magnet arrangement structure (5, 6) can move slightly in the axial direction x, which allows for tolerance compensation due to temperature changes, for example.

[0040] In other words, the second embodiment also has a single wave retaining ring as spring 8, but with a one-piece yoke 6. The tubular section 18 of the yoke 6 does not cause the magnetic ring 5 to extend axially. The wave retaining ring 8 applies axial pressure against the recess wall 26 in the cylinder 7 and against the yoke-magnet arrangement (5, 6) (particularly against the yoke 6, from its shoulder 16 to the magnetic ring 5 and via the magnetic ring 5 to the immovable stop 9), thereby forcing the magnetic ring 5 against the immovable stop 9. Since the yoke 6 does not have a right shoulder, the magnetic ring 5 is in direct contact with the immovable stop 9.

[0041] according to Figures 4a to 4d In the third embodiment of the movable system 4 shown, the yoke-magnet arrangement also includes a single-piece yoke 6. The yoke 6 also has a tubular section 18 for receiving the magnetic ring 5 and a radially outer shoulder 16 for axially positioning the magnetic ring 5 on the tubular section 18.

[0042] Unlike the second embodiment, the immovable stop 9 of the cylinder 7 is not a radially outer shoulder, but has a plurality of radial protrusions 28a, 28b, 28c, 28d, which are evenly distributed on the circumference of the cylinder 7. Here, four radial protrusions 28a, 28b, 28c, 28d are provided. To interact with the toothed radial protrusions 28a, 28b, 28c, 28d, the tube section 18 of the yoke 6 has a plurality of axial protrusions 30a, 30 at its front end, which define recesses 32a, 32b between them. Here, four radial protrusions 28a, 28b, 28c, 28d, four axial protrusions 30a, 30b, and four recesses 32a, 32b are provided. The recesses 32a, 32b have extensions in the circumferential direction so that the radial protrusions 28a, 28b, 28c of the cylinder 7 can be inserted during assembly. The axial extension of the receiving area formed by the tubular section 18 for the magnetic ring 5 is smaller than the axial extension of the magnetic ring 5, so that a gap 24 is established between the immovable stop 9 and the yoke 6 in the assembled state.

[0043] The cylinder 7 also has an annular groove 10 for receiving the spring 8, which in this embodiment is also a retaining ring.

[0044] In the assembled state, the magnetic ring 5 is positioned on the tubular section 18 and held between the immovable stop 9 (radial protrusions 28a, 28b, 28c) of the cylinder 7 and the spring 8 (retaining ring) in the groove 10. The axial protrusions 30a, 30b of the yoke 6 are positioned between the radial protrusions 28a, 28b, 28c, 28d of the cylinder 7, and vice versa. Thus, due to the retaining ring 8 (spring), the yoke-magnet arrangement structure (5, 6) can move slightly in the axial direction x, which allows for, for example, tolerance compensation due to temperature changes.

[0045] In other words, the third embodiment has a single wave retaining ring 8 as a spring and a one-piece yoke 6. The yoke 6 extends along the entire axial extension of the magnetic ring 5 via its axial protrusions 30a, 30b (it passes through both sides of the magnetic ring 5), which has a positive effect on the electromagnetic field distribution. The wave retaining ring 5 applies pressure against the groove wall 26 in the cylinder 7 and against the yoke-magnet arrangement structure (particularly against the yoke 6, from its shoulder 16 to the magnetic ring 5 and through the magnetic ring 5 to the immovable stop 9), thereby forcing the magnetic ring 5 against the immovable stop 9. Since the yoke 6 does not have a right shoulder, the magnetic ring 5 is in direct contact with the immovable stop 9.

[0046] according to Figures 5a to 5dIn the fourth embodiment of the movable system 4 shown, the yoke-magnet arrangement also includes a single-piece yoke 6. The yoke arrangement structure and cylinder 7 are designed according to the second embodiment, i.e., the cylinder 7 has a plurality of radial protrusions 28a, 28b, 28c, 28d serving as immovable stops 9, these radial protrusions being evenly distributed on the circumference of the cylinder 7, and the yoke 6 having a plurality of axial protrusions 30a, 30b at its front end, the plurality of axial protrusions defining recesses 32a, 32b between them. Here, four radial protrusions 28a, 28b, 28c, 28d, four axial protrusions 30a, 30b, and four recesses 32a, 32b are also provided. The recesses 32a, 32b have extensions in the circumferential direction, such that the radial protrusions 28a, 28b, 28c, 28d of the cylinder 7 can be inserted during assembly. The axial extension of the receiving area formed by the tubular section 18 for the magnetic ring 5 is smaller than the axial extension of the magnetic ring 5, so that a gap 24 is established between the immovable stop 9 and the yoke 6 in the assembled state.

[0047] Unlike the third embodiment, the cylinder 7 does not have an annular groove 10 for receiving the retaining ring of the spring 8. According to the fourth embodiment, the spring 8 is a wave-shaped ring positioned on the outer surface of the cylinder 7 and held in place via an insert 11 that acts as a spring support. The insert 11 has an annular shape, having a radially outer shoulder 34 and a radially inner ring element 35 extending inside the cylinder 7, against which a piston spring 36 presses. The insert 11 is fixed to the cylinder 7 by means of the piston spring 36. Because the piston spring 36 is much stronger than the spring 8 that holds the yoke-magnet arrangement, the spring 8 is nearly axially fixed to the cylinder 7. During the thermal expansion of the yoke-magnet arrangement, the spring 8 will not move backward due to the strong piston spring.

[0048] In the assembled state, the magnetic ring 5 is positioned on the tubular section 18 and clamped between the immovable stop 9 (radial protrusions 28a, 28b, 28c, 28d) of the cylinder 7 and the spring 8 (wave ring) held in place via the insert 11. The axial protrusions 30a, 30b of the yoke 6 are positioned between the radial protrusions 28a, 28b, 28c, 28d of the cylinder 7, and vice versa. Thus, due to the wave ring 7 (spring), the yoke-magnet arrangement structure (5, 6) can move slightly in the axial direction x, which allows for, for example, tolerance compensation due to temperature changes.

[0049] In other words, the third embodiment does not require any cylinder recess. Instead, an insert 11 is provided to support the spring 8. The insert 11 is releasably secured to one side of the cylinder 7. Furthermore, since no recess is needed to hold the spring 8 in place on the cylinder 7, the spring 8 can be a closed wave ring. Further, the insert 11 acts as a centering device for the wave ring (spring 8) on the cylinder 7.

[0050] It should be noted that the first, second and third embodiments may also be equipped with an insert 11 instead of providing a cylinder recess 10.

[0051] A linear compressor for a household appliance (e.g., a refrigerator) is disclosed, wherein a yoke-magnet arrangement is clamped onto a cylinder of a cylinder-piston arrangement in a manner that allows for the thermal expansion of the yoke-magnet arrangement; particularly by means of a fixed stop member of the cylinder, which forces the yoke-magnet arrangement against the cylinder via a spring force. A household appliance is also disclosed.

[0052] Figure Labels

[0053] 1 Linear compressor

[0054] 2 stators

[0055] 3 coils

[0056] 4. Mobile System

[0057] 5 Magnet Rings

[0058] 6-yoke

[0059] 7 cylinders

[0060] 8 springs

[0061] 9 Immovable stop parts

[0062] 10. Annular groove (cylinder groove)

[0063] 11 inserts

[0064] 12-piston

[0065] Room 13

[0066] 14 circled areas

[0067] 16 yoke shoulder

[0068] 18 tubular sections

[0069] 20 tubular sections

[0070] 22 shoulder of the yoke

[0071] The gap between the 24 yoke parts

[0072] 26 groove walls

[0073] 28a, 28b, 28c, 28d radial protrusions

[0074] 30a, 30b Axial protrusions

[0075] 32a, 32b recessed parts

[0076] Shoulder of 34 inserts

[0077] 35 inner ring element

[0078] 36 Piston Spring

Claims

1. A linear compressor (1) for household appliances, said linear compressor having: Linear electric motors, including: Stator (2) having coil (3); and a movable system (4) capable of moving along the axial direction (x) and comprising: Yoke-magnet arrangement structure (5, 6); Cylinder 7; and Spring 8; -The yoke-magnet arrangement structure includes an annular yoke (6), which is arranged on the cylinder (7) and carries a magnetic ring (5); -In this configuration, via the spring (8), the yoke-magnet arrangement structure (5, 6) presses against the immovable stop (9) on the cylinder (7), thus restricting the yoke on one side. - The magnet arrangement structure (5, 6) moves axially on the cylinder (7); and -The yoke (6) has a shoulder (16) facing the immovable stop (9) and restricting the axial movement of the magnetic ring (5) on the yoke (6) on the other side.

2. The linear compressor according to claim 1, wherein, The spring (8) acts directly on the yoke.

3. The linear compressor according to claim 1 or 2, wherein, The spring (8) is a ring and has a wavy shape.

4. The linear compressor according to claim 1, 2 or 3, wherein, The spring (8) is a retaining ring and is arranged in the cylinder recess (10).

5. The linear compressor according to any one of claims 1, 2, or 3, wherein, The spring (8) is a ring that is held in place by an insert (11) that surrounds the cylinder (7) and acts as a spring support.

6. The linear compressor according to any one of claims 1 to 4, wherein, The yoke (6) is divided into two annular yoke portions (6a, 6b), each annular yoke portion having a shoulder (16, 22) for limiting the axial movement of the magnetic ring (5).

7. The linear compressor according to claim 6, wherein if the circular yoke portions (6a, 6b) are placed together, the axial extension of the receiving area (18, 20) for the magnetic ring (5) is smaller than the axial extension of the magnetic ring (5).

8. The linear compressor according to any one of claims 1 to 5, wherein the yoke has a tubular section (18) for receiving the magnetic ring (5), wherein, The axial extension of the tubular section is smaller than the axial extension of the magnetic ring (5).

9. The linear compressor according to any one of claims 1 to 5, wherein, The yoke has a tubular section (18) with axial protrusions (30a, 30b) at its front end, the axial protrusions being adapted to pass between radial protrusions (28a, 28b, 28c, 28d) of the cylinder (7), the radial protrusions being spaced apart from each other in the circumferential direction and forming the immovable stop (9) on the cylinder (7).

10. The linear compressor according to claim 9, wherein the tubular section (18) for receiving the magnetic ring (5) has an axial extension smaller than the axial extension of the magnetic ring (5).

11. A household appliance having a linear compressor (1) according to any one of the preceding claims.

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