CN215934538U

CN215934538U - Motor, compressor and refrigeration plant

Info

Publication number: CN215934538U
Application number: CN202122283352.0U
Authority: CN
Inventors: 张德金; 李宏涛; 邱小华
Original assignee: Guangdong Meizhi Compressor Co Ltd
Current assignee: Guangdong Meizhi Compressor Co Ltd
Priority date: 2021-09-18
Filing date: 2021-09-18
Publication date: 2022-03-01
Anticipated expiration: 2031-09-18

Abstract

The utility model discloses a motor, a compressor and refrigeration equipment, wherein the motor comprises a stator and a rotor, the stator comprises a plurality of stator punching sheets which are arranged along the axial direction in a laminating way, and each stator punching sheet is provided with 12 stator teeth; the rotor has 8 rotor magnets; the stator punching sheet is provided with two opposite first sides and two opposite second sides, and the maximum relative position distance between the first sides is equal to the maximum relative position distance between the second sides. The technical scheme of the utility model can reduce the noise generated by the motor and simultaneously reduce the production cost of the motor.

Description

Motor, compressor and refrigeration plant

Technical Field

The utility model relates to the technical field of motors, in particular to a motor, a compressor and refrigeration equipment.

Background

At present, refrigeration equipment such as a refrigerator and a freezer needs to be provided with a compressor to realize the refrigeration function, along with the promotion of the market on the energy efficiency grade requirement of the refrigeration equipment, the type of the compressor in the equipment needs to be converted from a constant-speed compressor to a variable-frequency compressor, a motor in the existing compressor can generate large noise under the variable-frequency control, the use experience of a user is influenced, and the production cost of the existing motor is high.

SUMMERY OF THE UTILITY MODEL

The utility model mainly aims to provide a motor, aiming at reducing the noise generated by the motor and reducing the cost of the motor.

In order to achieve the above object, the present invention provides a motor including:

the stator comprises a plurality of stator laminations which are arranged along the axial direction in a laminated mode, and each stator lamination is provided with 12 stator teeth; and

a rotor having 8 rotor magnets;

the stator punching sheet is provided with two opposite first sides and two opposite second sides, and the maximum relative position distance between the first sides is equal to the maximum relative position distance between the second sides.

Optionally, the second side includes a first straight section, a second straight section and a connecting side section connecting the first straight section and the second straight section, and a relative position distance between the second straight sections of the second side is smaller than a relative position distance between the first straight sections of the second side.

Optionally, the number of the second straight-edge sections and the number of the connecting-edge sections are both two, and two ends of the first straight-edge section are connected with one of the second straight-edge sections through one of the connecting-edge sections.

Optionally, a relative position distance between the first straight sections of the two second side edges is a, a relative position distance between the second straight sections of the two second side edges is B, and B/a is greater than or equal to 0.75 and less than 1.

Optionally, the length of the first straight section is less than twice the length of the second straight section plus 1.5 millimeters.

Optionally, the connecting edge section is arranged in a straight edge.

Optionally, the outer edge of the stator punching sheet is provided with 4 mounting holes, and the 4 mounting holes are arranged in a matrix.

Optionally, a distance between the mounting hole and the first side edge closest to the mounting hole is greater than or equal to 1mm, and/or a distance between the mounting hole and the second side edge closest to the mounting hole is greater than or equal to 1 mm.

Optionally, the stator punching sheet has diagonal corners located at a joint of the first side edge and the second side edge, the number of the diagonal corners is four, and the four diagonal corners are arranged in a chamfer manner.

The utility model also provides a compressor, which comprises the motor in any embodiment.

The utility model also provides refrigeration equipment comprising the compressor.

The motor comprises a stator and a rotor, wherein the stator is provided with 12 stator teeth, the rotor is provided with 8 rotor magnets, namely the motor is 12-slot 8-level, the minimum common multiple of the slot level ratio is 24, so that the fundamental wave frequency of the cogging torque of the motor can be effectively increased, the fundamental wave amplitude is reduced due to the increase of the fundamental wave frequency of the cogging torque, and the noise caused by the cogging torque in the operation of the motor is effectively reduced; the stator punching sheet of the embodiment is provided with two opposite first side edges and two opposite second side edges, and the maximum relative position distance between the two first side edges is equal to the maximum relative distance between the two second side edges, so that the widths of the stator yoke parts of the stator punching sheet are approximately the same, the efficiency loss and harmonic distortion caused by local magnetic density increase are avoided, the frequency conversion control is facilitated, and the noise is reduced; moreover, compare circular shape stator punching among the prior art, the stator punching of this embodiment can improve the utilization ratio of material, reduces material cost, reduces the manufacturing cost of motor.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an embodiment of an electric machine according to the present invention;

FIG. 2 is a schematic structural diagram of a stator lamination according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another embodiment of a stator lamination of the present invention;

FIG. 4 is a schematic structural diagram of a stator lamination according to another embodiment of the present invention;

fig. 5 is a layout view of the stator punching sheet in fig. 2 formed by cutting;

fig. 6 is a layout diagram of the stator punching sheet in fig. 2 formed on the material belt by punching;

FIG. 7 is an enlarged view taken at I in FIG. 6;

fig. 8 is a layout diagram of a stator punching sheet formed by punch forming on a material belt according to still another embodiment of the present invention.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				10	Electric machine	121	A first straight section
100	Stator	122	Second straight side section
				100a	Stator punching sheet	123	Connecting edge section
101	Stator yoke	130	Mounting hole
				102	Stator tooth	140	Chamfering
103	Stator slot	200	Rotor
				110	The first side edge	20	Material belt
120	Second side edge

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The utility model provides a motor.

In particular, the motor is suitable for compressors in refrigeration equipment such as refrigerators and freezers with small and medium volumes, and is particularly suitable for reciprocating compressors, and the application of the motor to the reciprocating compressors will be described in detail below.

At present, a compressor in refrigeration equipment such as a refrigerator with a medium and small volume and a freezer with a medium and small volume generally adopts a 6-slot motor or a 9-slot motor to realize a refrigeration function, and the refrigeration equipment with the medium and small volume needs to be changed from constant speed control to variable frequency control along with the improvement of the requirement on the refrigeration equipment, but the motor structure of the 6-slot motor or the 9-slot motor is not suitable for variable frequency control, and overlarge noise can be generated during the variable frequency control.

Moreover, general motor stator is circular, and the stator is towards the piece through stamping forming usually, because the restriction of stator towards the piece appearance, the stock layout distance of stator towards the piece is great in stamping process, and has too much material not utilized between the adjacent stator towards the piece for the material waste is comparatively serious, has increased material cost, and then leads to motor and refrigeration plant's manufacturing cost to improve.

For such refrigeration equipment with medium and small volumes which are placed in rooms, the noise level is an important index influencing the use comfort level, too much noise greatly influences the use comfort level of users, meanwhile, the production cost of the refrigeration equipment determines the selling price of the refrigeration equipment, and the cost is increased due to too high cost, so that the problem that how to reduce the noise generated by the refrigeration equipment with the medium and small volumes and reduce the production cost are urgently needed to be solved at present.

To solve the above problems, referring to fig. 1 to 2, in an embodiment of the present invention, the motor 10 includes a stator 100 and a rotor 200; the stator 100 comprises a plurality of stator laminations 100a stacked along the axial direction of the stator, and each stator lamination 100a is provided with 12 stator teeth 102; the rotor 200 has 8 rotor magnets; the stator punching sheet 100a has two opposite first sides 110 and two opposite second sides 120, and a maximum relative position distance between the two first sides 110 is equal to a maximum relative position distance between the two second sides 120.

It can be understood that the stator 100 includes a stator core and a winding, and the stator core is formed by laminating a plurality of stator laminations 100a, so that the eddy current loss and the temperature rise can be reduced. The stator core includes a stator yoke 101 and a plurality of stator teeth 102; the stator yoke 101 may be annular, a plurality of stator teeth 102 are uniformly spaced on the stator yoke 101 and may extend toward the center of the stator 100, any two adjacent stator teeth 102 may surround the stator yoke 101 to form a stator slot 103 with an opening facing the center of the stator 100, and the winding is embedded in the stator slot 103 and wound around the periphery of the stator teeth 102. Each stator lamination 100a of the stator core of the present embodiment has 12 stator teeth 102, that is, the stator core has 12 stator slots 103.

A rotor 200 including a rotor core and a rotor magnet; correspondingly, in order to reduce eddy current loss and temperature rise, the rotor core can be formed by axially laminating a plurality of rotor punching sheets. Each rotor punching has 8 magnet mounting holes, and 8 magnet mounting holes are even interval setting, and when a plurality of rotor punching folded and press formation rotor core, the magnet mounting hole on each rotor punching corresponds the intercommunication and forms the magnet mounting groove, 8 one-to-one of rotor magnet install in 8 magnet mounting grooves. It can be understood that the rotor magnet installed in one magnet installation slot is one pole, while the motor 10 of the compressor in the existing refrigerating equipment with medium and small volume is generally a 6-slot 4-pole or 9-slot 6-pole motor 10, and the least common multiple of the slot pole ratio is 12 or 18 respectively, and the applied technical scheme can effectively increase the fundamental wave frequency of the cogging torque of the motor 10 by adopting the structure of the 12-slot 8-pole motor 10, and the fundamental wave amplitude can be reduced due to the increase of the fundamental wave frequency of the cogging torque, so that the noise caused by the cogging torque in the operation of the motor 10 can be effectively reduced.

As can be understood, since the motor 10 is applied to the reciprocating compressor, in order to adapt to the mounting hole of the crankcase of the reciprocating compressor, the stator lamination 100a of the present embodiment further has two opposite first sides 110 and two opposite second sides 120, and the maximum relative position distance between the two first sides 110 is equal to the maximum relative position distance between the two second sides 120, so that the shape of the stator core of the present embodiment is substantially "square", so that the widths of the stator yoke portions 101 are substantially the same, the width difference of the stator yoke portions 101 is prevented from being large, the uneven magnetic force generated by the stator teeth 102 due to the large local magnetic density and the small local magnetic density of the stator 100 is avoided, and the noise generated due to the unstable frequency conversion control effect of the motor 10 is avoided. Specifically, in the present embodiment, the maximum relative distance between the first side edges 110 and the maximum relative distance between the second side edges 120 are both 84 mm.

It should be noted that the stator punching sheet 100a and the rotor punching sheet described in this specification may be formed by punch forming, laser cutting, or water jet cutting.

Moreover, it can be understood that, because the stator lamination 100a is substantially square, compared with the existing circular stator lamination 100a, no matter through stamping, laser cutting or water jet cutting, when the stator lamination 100a is subjected to sample arrangement, the gap between every two adjacent stator laminations 100a is small, the utilization rate of materials can be improved, the waste of the materials is reduced, so that the material cost is reduced, and further, the production cost of the motor 10 is reduced.

The motor 10 of the technical scheme of the utility model comprises a stator 100 and a rotor 200, wherein the stator 100 is provided with 12 stator teeth 102, the rotor 200 is provided with 8 rotor magnets, namely the motor 10 of the utility model is 12-slot 8-level, and the least common multiple of the slot level ratio is 24, so that the fundamental wave frequency of the cogging torque of the motor 10 can be effectively increased, the fundamental wave amplitude can be reduced due to the increase of the fundamental wave frequency of the cogging torque, and the noise caused by the cogging torque in the operation of the motor 10 can be effectively reduced; the stator punching sheet 100a of the embodiment has two opposite first sides 110 and two opposite second sides 120, and the maximum relative position distance between the two first sides 110 is equal to the maximum relative distance between the two second sides 120, so that the widths of the stator yoke portions 101 of the stator punching sheet 100a are approximately the same, efficiency loss and harmonic distortion caused by local magnetic density increase are avoided, frequency conversion control is facilitated, and noise generation is reduced; moreover, compared with the circular stator punching sheet 100a in the prior art, the stator punching sheet 100a of the embodiment can improve the utilization rate of materials, reduce the material cost, and reduce the production cost of the motor 10.

Referring to fig. 3 and 4, in an embodiment, the second side edge 120 includes a first straight edge section 121, a second straight edge section 122, and a connecting edge section 123 connecting the first straight edge section 121 and the second straight edge section 122, and a relative position distance between the second straight edge sections 122 of the two second side edges 120 is smaller than a relative position distance between the first straight edge sections 121 of the two second side edges 120.

The stator 100 has a horizontal center line passing through the center of the stator 100 and a vertical center line passing through the center of the stator 100, where the former is defined as a first center line and the latter is defined as a second center line. The two first straight sections 121 of the two second side edges 120 may be symmetrically arranged with respect to a first central line of the stator lamination 100a, that is, the two second straight sections 122 of the two second side plates are located on the same side of a second central line of the stator lamination 100a, as shown in fig. 3; the two second straight sections 122 of the two second side edges 120 may also be arranged in a center-to-center array with respect to the stator center, that is, the two second straight sections 122 of the two second side edges 120 are respectively and correspondingly located at two sides of the second central line of the stator lamination 100a, as shown in fig. 4.

Referring to fig. 2, 5 and 6, in order to further improve the material utilization rate, in another embodiment, the number of the second straight section 122 and the connecting side section 123 is two, and both ends of the first straight section 121 are connected to the second straight section 122 through one connecting side section 123. In this embodiment, in order to simultaneously ensure the uniformity of the width of the stator yoke portion 101, the lengths of the two second straight-side segments 122 are equal, and the lengths of the two connecting-side segments 123 are equal, that is, the two second straight-side segments 122 and the two connecting-side segments 123 of each second side edge 120 are symmetrically arranged about the second central line.

With such an arrangement, when the stator laminations 100a are formed by laser cutting or water jet cutting, every three adjacent stator laminations 100a can be arranged in a 'common-edge' manner, as shown in fig. 5, along the direction of the second central line (vertical direction in the figure), the two connecting edge sections 123 of one stator lamination 100a located above are respectively overlapped with the respective corresponding connecting edge sections 123 of the two stator laminations 100a located below, so that, compared with the prior art, the gap between every two adjacent stator laminations 100a is eliminated, the material waste is reduced, the material utilization rate is improved, and the material cost is reduced.

Moreover, as shown in fig. 6, in this embodiment, the central points of every two adjacent stator laminations 100a may be located on the same arrangement axis, and the plurality of stator laminations 100a may be arranged to form a regular arrangement, so that the stator laminations 100a may be formed by stamping. Specifically, when the stator punching sheets 100a are formed by stamping, taking the arrangement of the stator punching sheets 100a in three rows in fig. 6 as an example, a distance between first straight edge sections 121 of two second side edges 120 of the stator punching sheets 100a is defined as a, a distance between second straight edge sections 122 of the two second side edges 120 is defined as B, a distance between every two adjacent rows of the stator punching sheets 100a is defined as F (the two adjacent rows of the stator punching sheets 100a cannot share a common edge by stamping, and a gap needs to be reserved between every two adjacent stator punching sheets 100 a), and a minimum width of the material tape 20 is defined as L, in this embodiment, the minimum width L1 of the material tape 20 is 2 × a + B +4 × F; when the second side edge 120 is a whole straight edge section, referring to fig. 8, the minimum width L2 of the tape 20 is 3 × a +4 × F, and since the relative position distance between the second straight edge sections 122 of the two second side edges 120 is smaller than the relative position distance between the first straight edge sections 121 of the two second side edges 120, that is, B is smaller than a, it is obvious that L1 is smaller than L2, that is, the width of the tape 20 required by the latter in stamping is larger than the width of the tape 20 required by the former in stamping, therefore, on the premise of the same arrangement number, the width of the tape 20 is reduced in the embodiment, so that the utilization rate of the material is increased, the material cost is reduced, and the production cost of the motor 10 is reduced. Moreover, the stator punching sheets 100a in every two adjacent rows are arranged in a staggered mode, correspondingly, two adjacent punching heads of the punching die are also arranged in a staggered mode, the structure of the punching die can be simplified, and the situation that the punching heads are arranged crowded and the punching die is inconvenient to assemble is avoided.

Further, in order to improve the material utilization rate and avoid affecting the width of the stator yoke 101, in an embodiment, the relative position distance between the first straight sections 121 of the two second sides 120 is a, the relative position distance between the second straight sections 122 of the two second sides 120 is B, and B/a is greater than or equal to 0.75 and less than 1.

Further, when the stator laminations 100a are formed by stamping, in order to ensure a minimum distance between two adjacent stator laminations 100a and reduce wear of a stamping die and stress variation of the outer edge of the stator laminations 100a, in an embodiment, the length of the first straight-side section 121 is less than twice the length of the second straight-side section 122 plus 1.5 mm.

Specifically, referring to fig. 6 and 7, fig. 6 is a layout diagram of the stator laminations 100a in fig. 2 formed on the tape 20 by stamping, fig. 7 is an enlarged view of fig. 6 at i, where a length of a first straight-side segment 121 of a second side 120 of the stator lamination 100a is defined as W, a length of a second straight-side segment 122 of the second side 120 is defined as H, a layout distance between every two adjacent stator laminations 100a in each row of stator laminations 100a is defined as D, and a distance between end points of every two adjacent second straight-side segments 122 of every two adjacent stator laminations 100a in each row of stator laminations 100a is defined as E. It can be understood that, since there is a space between every two adjacent rows of stator laminations 100a, W is inevitably less than E, and as can be seen from fig. 7, E is 2 × H + D, and therefore W is less than 2 × H + D. In this embodiment, in order to ensure the minimum distance between two adjacent stator laminations 100a, reduce the wear of the stamping die, and prevent the outer edge of the stator laminations 100a from deforming due to stress, the layout distance D between two adjacent stator laminations 100a is preferably 1.5mm, i.e., W is less than 2 × H +1.5mm, so that the length of the first straight-side segment 121 is less than twice the length of the second straight-side segment 122 plus 1.5 mm.

Of course, in other embodiments, the layout distance D between every two adjacent stator laminations 100a in each row of stator laminations 100a may also be 1mm, 2mm, and the like according to different requirements.

Referring to fig. 2, in an embodiment, the connecting edge section 123 is a straight edge. As can be understood, the connecting edge sections 123 are arranged in a straight edge manner, so that on one hand, when the stator laminations 100a are formed by laser cutting or water jet cutting, the 'common edge' arrangement of the adjacent stator laminations 100a can be ensured, and the utilization rate of materials is improved; on the one hand, when stator punching 100a passes through stamping forming, can reduce the interval of arranging of adjacent stator punching 100a, improve the utilization ratio of material. Of course, in other embodiments, the connecting edge section 123 may also be disposed in a concave-convex structure, for example, the connecting edge section 123 may have a "wave" structure, or a "zigzag" structure.

Referring to fig. 2, in an embodiment, the outer edge of the stator lamination 100a has 4 mounting holes 130, and the 4 mounting holes 130 are arranged in a matrix. It is understood that the mounting hole 130 corresponds to a hole site of a crankcase of the reciprocating compressor, and the stator core is coupled to the crankcase of the reciprocating compressor by a fastening member by inserting the fastening member into the mounting hole 130.

It can be understood that when the stator lamination 100a is formed by laser cutting, since laser cutting inevitably generates a thermal influence, if the distance between the mounting hole 130 and the first side edge 110 and the second side edge 120 closest to the mounting hole is too small, the mounting hole 130 and the portions of the first side edge 110 and the second side edge 120 closest to the mounting hole are easily burned through, and the stator lamination 100a is discarded; when the stator punching sheet 100a is formed by stamping, if the distance between the mounting hole 130 and the nearest first side 110 and second side 120 is too small, the outer edge of the stator punching sheet 100a is easily deformed, so that the stator punching sheet 100a cannot be laminated tightly. In order to prevent the above problem and improve the strength of the stator punching sheet 100a, in an embodiment of the present invention, a distance between the mounting hole 130 and the first side edge 110 closest to the mounting hole is greater than or equal to 1mm, and/or a distance between the mounting hole 130 and the second side edge 120 closest to the mounting hole is greater than or equal to 1 mm.

Referring to fig. 2, in an embodiment, the stator lamination 100a has four opposite corners located at a connection between the first side 110 and the second side 120, and the four opposite corners are provided as chamfers 140. It will be appreciated that by providing the diagonal corners as chamfers 140, it is possible to avoid scratching the installer by making the four diagonal corners of the stator core too sharp.

The present invention further provides a compressor, which includes the motor 10 as described above, and the specific structure of the motor 10 refers to the above embodiments, and since the compressor adopts all technical solutions of all the above embodiments, the compressor at least has all beneficial effects brought by the technical solutions of the above embodiments, and details are not repeated herein. Wherein, the compressor can include pivot, compression chamber and be located the piston assembly of compression chamber, and the both ends of pivot can be connected with piston assembly and the transmission of motor 10 rotor 200 respectively to make motor 10 rotor 200 when rotating, accessible pivot drive piston assembly reciprocates the multiple compression in the compression chamber, and then realizes exporting after the low temperature low pressure material compression that the compression chamber inserts is high temperature high pressure.

The present invention further provides a refrigeration apparatus, which includes the above-mentioned compressor, and the specific structure of the compressor refers to the above-mentioned embodiments, and since the refrigeration apparatus adopts all technical solutions of all the above-mentioned embodiments, the refrigeration apparatus at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, and details are not repeated herein. Wherein, the refrigeration equipment can be a refrigerator, an ice chest or an air conditioner.

The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. An electric machine, comprising:

a rotor having 8 rotor magnets;

2. The electric machine of claim 1 wherein said second side comprises a first straight section, a second straight section, and a connecting side section connecting said first straight section and said second straight section, the relative positional distance between the second straight sections of said second sides being less than the relative positional distance between the first straight sections of said second sides.

3. The motor according to claim 2, wherein the number of the second straight section and the number of the connecting side sections are two, and both ends of the first straight section are connected to one of the second straight sections through one of the connecting side sections, respectively.

4. The motor of claim 2, wherein the relative distance between the first straight sections of the two second sides is a, the relative distance between the second straight sections of the two second sides is B, and B/a is greater than or equal to 0.75 and less than 1.

5. The electric machine of claim 2 wherein the length of the first straight section is less than twice the length of the second straight section plus 1.5 millimeters.

6. An electrical machine according to claim 2, wherein the connecting edge section is straight.

7. The motor according to any one of claims 1 to 6, wherein the outer edge of the stator lamination is provided with 4 mounting holes, and the 4 mounting holes are arranged in a matrix.

8. The electric machine of claim 7, wherein the distance between the mounting hole and the first side closest thereto is greater than or equal to 1mm, and/or the distance between the mounting hole and the second side closest thereto is greater than or equal to 1 mm.

9. The motor according to any one of claims 1 to 6, wherein the stator punching sheet has four opposite corners at the joint of the first side and the second side, and the four opposite corners are arranged in a chamfer manner.

10. A compressor, characterized by comprising an electric machine according to any one of claims 1-9.

11. A refrigeration apparatus, comprising the compressor of claim 10.