Compressor, permanent magnet motor and method for holding a shaft

Abstract

A compressor (100) of a heating, ventilation and air conditioning (HVAC) system, comprising: a motor (110, 210, 310) comprising a rotor (114, 214, 314), the rotor (114, 214, 314) comprising a lamella pack section (370, 470); a plurality of permanent magnets (350) embedded in the lamination stack section (370, 470) of the rotor (114, 214, 314); a wave (116, 216, 316); a counterweight (230a, 230b, 33b) attached to the shaft (116, 216, 316); wherein the counterweight (230a, 230b, 33b) is separated from the permanent magnets (350), the rotor (114, 214, 314) has a central bore (215, 315) with a flank (211, 311), the shaft (116, 216, 316) has a step (217, 317), the shaft (116, 216, 316) has a diameter (D2) that is larger than a diameter (D3) of the central bore (215, 315), the step (217, 317) rests on the flank (211, 311) of the central bore (215, 315), the counterweight (230a, 230b, 33b) and the step (217, 317) at opposite ends the central bore (215, 315) are positioned, the counterweight (230a, 230b, 33b) has an interference fit with the shaft (116, 216, 316), wherein the central bore (315) has a keyway (340), the shaft (316) has a key (342) and the key (342) is fitted into the keyway (340), and wherein the counterweight (330b) has an alignment tongue (332), and the alignment tongue (332) is fitted into the keyway (340).

Description

Technical field

[0001] The present disclosure relates to a motor, for example, of a compressor, in a heating, ventilation, and air conditioning (HVAC) system. More specifically, the present disclosure relates to a motor comprising one or more permanent magnets. US 5,336,060 A describes a hermetically sealed compressor assembly comprising a motor-compressor and an electric drive motor with a vertical rotor, wherein the rotor includes a lower axial end ring with an integrally formed rotor counterweight. US 2006 / 0133944 A1 describes a scroll machine with a brushless permanent magnet motor, wherein the rotor for the motor comprises a vane rotor body as well as an upper and a lower counterweight. US 4,795,936 A describes a rotating shaft system comprising a rotor with a core consisting of a stack of circular laminates of magnetic material and permanent magnets.US 5,666,015 A describes a rotor of an electric motor for a compressor that prevents the generation of eddy currents and reduces flux leakage between adjacent magnetic poles. It is an object of the invention to propose a compressor, a motor, and a method for retaining a shaft in a rotor. This object is achieved by a compressor according to claim 1, a rotor according to claim 8, and a method according to claim 15. background

[0002] An HVAC system often uses a compressor to compress the refrigerant. The compressor may be coupled to a motor, for example, an electric motor. Typically, an electric motor consists of a stationary stator and a rotating rotor. The rotor can be coupled to the shaft so that torque generated by the stator and rotor can be transferred from the rotor to the shaft, which drives the compressor. Summary

[0003] A motor can be coupled to a compressor, such as a scroll compressor, to drive a compression mechanism. The present embodiments relate to a motor with one or more permanent magnets embedded in a laminated core of the motor's rotor. The embodiments disclosed herein also provide methods and systems designed to assist in coupling a shaft to the rotor without utilizing heat that could demagnetize the permanent magnets in the motor.

[0004] In some embodiments, the motor may comprise a rotor with a laminated section. A plurality of permanent magnets may be embedded in the laminated section of the rotor. In some embodiments, the adjacent permanent magnets from among the plurality of permanent magnets may be arranged relative to each other at an angle of more or less than approximately 90 degrees from end to end.

[0005] The motor may also include a shaft coupled to the rotor, allowing the rotor to transmit torque to the shaft. In some embodiments, the shaft may be coupled to the rotor via a central bore in the rotor.

[0006] In some embodiments, the shaft and the rotor's central bore can have an interference fit. In some embodiments, the shaft can have a diameter larger than the diameter of the central bore, and the shaft can be shrink-fitted into the central bore (the central bore can be shrunk onto the shaft).

[0007] In some embodiments, the central bore may have a keyway and the shaft may have a key.

[0008] In some embodiments, the motor may include a counterweight mounted on the shaft. In some embodiments, the counterweight may have an interference fit with the shaft. In some embodiments, the rotor's central bore may have a flank, and the shaft may have a step. In some embodiments, the step may rest on the flank of the central bore. In some embodiments, the counterweight and the flank may be positioned at opposite ends of the central bore. In some embodiments, the flank and the counterweight may help to secure the shaft in the rotor's central bore. In some embodiments, the counterweight may have an alignment tongue that may be positioned in the keyway. The alignment tongue may help to align the counterweight relative to the shaft.

[0009] In some embodiments, the counterweight can be separated from the permanent magnets by a gap. In some embodiments, the permanent magnets and the counterweight can be separated by a partition plate.

[0010] Further features and aspects of the embodiments will become clear upon consideration of the following detailed description and the accompanying drawings. Brief description of the drawings

[0011] Reference is now made to the drawings in which identical reference numbers consistently represent corresponding parts. Fig. Figure 1 represents a spiral compressor with a motor. Fig. Figure 2 shows a cross-sectional view of a motor according to one embodiment. Fig. 3A to 3E represent aspects of a motor according to another embodiment. Fig. 3A is a cross-sectional view. Fig. 3B is a view of the end. Fig. 3C represents a counterweight. Fig. 3D represents a cross-sectional view of a rotor. Fig. 3E shows an enlarged view of one end of the engine. Fig. Figure 4 shows a perspective view of a rotor of another embodiment of a motor. Fig. 5A and Fig. Figure 5B shows schematic views of a double-pole permanent magnet motor. Fig. 5A represents directions of magnetic flux relative to a rotor. Fig. Figure 5B shows a schematic arrangement of permanent magnets relative to a rotor in a double-pole permanent magnet motor. Detailed description

[0012] A compressor, such as those used in an HVAC system, can be driven by a motor. Generally, an electric motor consists of a stationary stator and a rotating rotor. During operation, magnetic fields generated by the stator and rotor interact to produce torque. This torque is transmitted from the rotor to the compressor via a shaft located within the rotor. Increasing the efficiency of the electric motor is desirable to improve the overall efficiency of the HVAC system.

[0013] An electric motor generally comprises a stator and a rotor. The stator is generally stationary, while the rotor can generally rotate. During operation, the stator can provide a variable magnetic field, which results in torque between the stator and the rotor. One type of electric motor is a line-starting motor. A line-starting motor generally refers to a type of electric motor that is capable of starting from a standstill and accelerating to its rated speed when supplied with a constant-amplitude and constant-frequency voltage. One or more permanent magnets may be embedded in the rotor, which can increase the efficiency of line-starting motors. A line-starting motor with one or more permanent magnets embedded in the rotor is generally referred to as a line-starting permanent motor (LSPM).

[0014] Embodiments as disclosed herein generally relate to a motor (e.g., DSPM) that can be coupled to a compressor to drive the compressor. In some embodiments, the compressor may be a scroll compressor. In some embodiments, the compressor may be a screw compressor or other types of compressors. In some embodiments, the motor as described herein may comprise a plurality of permanent magnets embedded in a laminated core of a rotor of the motor. In some embodiments, the permanent magnets extend over the length of the laminated core of the rotor. The motor may comprise a shaft that may be coupled to the rotor in a central bore of the rotor. In some embodiments, the shaft may be coupled to the rotor by a keyway. In some embodiments, the shaft may be coupled to the rotor by an interference fit.In some embodiments, the shaft can be coupled to the rotor by means of a cold-shrink fit. In some embodiments, the motor can include a counterweight attached to the shaft. In some embodiments, the counterweight can help to hold the shaft to the rotor. The embodiments as disclosed herein can help to couple the shaft and the rotor without using heat that could demagnetize the permanent magnets. A compressor with a motor as disclosed herein can help to increase the efficiency of a compressor.

[0015] Reference is made to the accompanying drawings, which form part of this application and show exemplary embodiments illustrating how these embodiments can be operated. It is assumed that the terms used herein serve the purpose of describing the figures and embodiments and are not intended to be considered limiting to the scope of this application.

[0016] Fig. Figure 1 represents a spiral compressor 100 comprising a motor 110 and a spiral 120. The motor 110 includes a stator 112 and a rotor 114. The rotor 114 is coupled to a shaft 116. The shaft 116 is coupled to the spiral 120. The motor 110 can be housed in a casing 130 of the compressor 100.

[0017] In operation, the motor 110 can generate torque between the rotor 114 and the stator 112. This torque can be transmitted to the shaft 116, which is coupled to the rotor 114, which in turn drives a circular motion of the spiral 120. As refrigerant flows through the spiral 120, its circular motion compresses the refrigerant. The shaft 116 can also have an oil intake channel (not shown in the image). Fig. 1 shown, but see e.g. oil intake channel 220 in Fig. 2 for example) to direct oil 140 from the bottom of the housing 130, for example, to the spiral 120.

[0018] It should be clear that the embodiment, as in Fig. Figure 1 is shown as an example and the motor 110 can also be used with other types of compressors, such as a screw compressor.

[0019] A permanent magnet used in the motor 100 can, for example, be demagnetized by heat. Therefore, it is not desirable to use heat to expand the rotor 114, for example, when the shaft 116 is attached to the rotor 114. Fig. 2, 3A to 3C are directed towards embodiments that can help to create a shaft (e.g. the shaft 116 in Fig. 1) on a rotor (e.g. the rotor 114 in Fig. 1) to hold the rotor in place without using heat to expand it. In general, the embodiments disclosed herein include holding the rotor and shaft in place by an interference fit and / or a keyway. The embodiments disclosed herein may also include the use of a counterweight to help hold the shaft to the rotor.

[0020] Fig. Figure 2 shows a cross-section of a motor 210, which includes a shaft 216 and a rotor 214. The shaft 216 may include an oil intake channel 220. If the motor 210 is equipped with, for example, a scroll compressor (e.g., the scroll compressor 100 in Fig. 1) is used, the oil intake channel 200 can be designed to hold the oil (e.g. the oil 140 in Fig. 1) to the spiral (e.g. the spiral 120 in Fig. 1) to manage.

[0021] The shaft 216 can be held in the rotor 214 by an interference fit. The term "interference fit" generally means that the diameter D2 of the shaft 216 is larger than the diameter D3 of a central bore 215 of the rotor 214, so that force may be required to fit the shaft 216 into the central bore 215. Once the shaft 216 is inserted into the central bore 215 of the rotor 214, the interference fit between the shaft 216 and the central bore 215 can provide friction to transmit a torque from the rotor 214 to the shaft 216.

[0022] In some embodiments, the shaft 216 and the central bore 215 can have a sliding fit. The term "sliding fit" is a type of fit and generally means that the diameter D2 of the shaft 216 is the same as or smaller than the diameter D3 of the central bore 215, so that the shaft 216 can be fitted relatively easily into the central bore 215. In some embodiments, the diameter D2 of the shaft 216 can be shrunk, for example, by cold shrinking. For instance, the shaft 216 can be immersed in liquid nitrogen to shrink its diameter D2. In some embodiments, the diameter D2 after cold shrinking can be smaller than the diameter D3 of the central bore 215. Cold shrinking can help to fit the shaft 216 into the central bore 215.When the shaft 216 returns to a normal temperature, such as room temperature, the shaft 216 and the central bore 215 can, for example, form an interference fit.

[0023] The wave 216 can also include one or more counterweights 230a and 230b. The counterweights 230a and 230b can be adapted to the wave 216 near a first end 216a and a second end 216b of the wave 216, respectively. In the orientation as shown in Fig. As shown in 2, the motor is positioned in a vertical direction. In the vertical direction as in Fig. As shown in Figure 2, the first counterweight 230a can be fitted to the shaft 216 from the upper end of the motor 210 and the second weight 230b can be fitted to the shaft 216 from the lower end of the motor 210.

[0024] The shaft 216 can include a step 217, and the rotor 214 can include a flank 211. When the shaft 216 is fitted into the central bore 215 of the rotor 214 from the top in the vertical direction, the shaft 216 can be pushed into the central bore 215 until the step 217 rests on the flank 211. After the shaft 216 is fitted into the central bore 215 until the step 217 rests on the flank 211, the second counterweight 230b can be fitted onto the shaft 216 from the lower end of the motor 210. The second counterweight 230b can have an opening 231 through which the shaft 216 can pass. The opening 231 and the shaft 216 can form an interference fit.

[0025] The second counterweight 230b can be slid along the shaft 216 until it rests on one end 214b of the rotor 214. The contact between the flank 211 and the step 217 and / or the interference fit between the second counterweight 230b and the rotor 214 can help to hold the shaft 216 in the central bore 215. Particularly preferably, the contact between the flank 211 and the step 217 and / or the interference fit between the second counterweight 230b and the rotor 214 can help to prevent the shaft 216 from sliding relative to the vertical direction in the central bore 215.

[0026] The first counterweight 230a can be fitted to the shaft 216 from the upper end of the motor 210. The first and second counterweights 230a and 230b can help to balance the shaft 216 when the shaft 216 rotates.

[0027] Fig. 3A to 3D represent another embodiment of the motor 310. Referring to Fig. 3A The motor 310 comprises a shaft 316 and a rotor 314. The rotor 314 can include a keyway 340 into which a key 342 of the shaft 316 can fit.

[0028] As in Fig. 3A and Fig. As shown in Figure 3B, the keyway 340 is an expanded space extending from the central bore 315 along a length L3 of the central bore 315. The key 342 and the keyway 340 can be designed to be complementary, such that the key 342 can be fitted into the keyway 340 along at least a section of length L3. The key 342 and the keyway 340 can form an interference fit to hold the shaft 316 to the rotor 314.

[0029] When assembling the motor 310, the key 342 of the shaft 316 can be aligned with the keyway 340 of the rotor 314. The shaft 316 can be pushed into the central bore 340, while the key 342 is pushed into the keyway 340.

[0030] The shaft 316 can have a step 317 and the rotor 314 can have a flank 311. In the direction as in Fig. As shown in Figure 3A, the shaft 316 can be pushed into the central bore 315 from an upper side of the motor 310 towards a lower side of the motor 310 until the stage 317 contacts the flank 311, which thus prevents the shaft 316 from being pushed further into the central bore 340.

[0031] A counterweight 330b can be fitted onto the shaft 316 from the lower side of the motor 310. The counterweight 330b and the shaft 316 can form an interference fit. The interference fit between the counterweight 330b and the rotor 314 and / or the contact between the flank 311 and the step 317 can help to prevent the shaft from sliding relative to the shaft 316 (i.e., in the direction defined by the length D3), as shown in Fig. 3A shown.

[0032] Referring to Fig. 3C, the counterweight 330b can have a balancing mass section 331, which can be designed to align with the shaft 316 (as in Fig. (3A shown) to compensate for changes during operation. The counterweight 330b can include an alignment tongue 332. In some embodiments, the alignment tongue 332 can be configured to fit into the keyway 340 of the rotor 314. Thus, it is clear that the aligned tongue 332 can be inserted into other sections of the rotor 314, such as another radial section.

[0033] The relative position of the alignment tongue 332 and the counterweight section 331 can be designed to help simplify the installation procedure of the counterweight 330b. In general, referring back to Fig. 2. Each of the first counterweight 230a and the second counterweight 230b can have a balancing mass section. Generally, the balancing mass section of the first counterweight 230a and the balancing mass section of the second counterweight 230b are located approximately 180 degrees relative to each other. If the first and second counterweights 230a and 230b do not have the alignment tongue, the relative position of the first and second counterweights 230a and 230b must be adjusted after the counterweights 230a and 230b are mounted on the shaft 216.

[0034] The alignment tongue 332 can help to position the counterweight 330b relatively easily in the correct position. Referring to Fig. 3A and Fig. 3C, since the counterweight 330b has the alignment tongue 332, the position of the counterweight 330b can be determined relatively easily by aligning the alignment tongue 332 to the keyway 340.

[0035] Referring back to Fig. 3B One or more permanent magnets 350 can be embedded in the rotor 314. The permanent magnets 350 can, for example, be embedded in a laminated section 370 of the rotor 314. In the illustrated embodiment, the number of permanent magnets 350 is four (permanent magnet 350a-d), provided that the number of permanent magnets 350 can be other numbers.

[0036] As shown, the permanent magnets 350a-d are configured such that the angle between any two adjacent permanent magnets 350a-d is greater or less than 90 degrees. For example, the angle a between permanent magnets 350a and 350c is typically greater than 90 degrees, and the angle b between permanent magnets 350c and 350d is typically less than 90 degrees. In some embodiments, the angle b between permanent magnets 350c and 350d (as well as the angle between permanent magnets 350a and 350b) is approximately 60-66 degrees. In some embodiments, the angle a between permanent magnets 350b and 350d (as well as the angle between permanent magnets 350a and 350c) is at least or approximately 114 degrees.

[0037] If the angle b between two adjacent permanent magnets 350c and 350d is less than 90 degrees, the adjacent permanent magnets 350c and 350d can be separated by a relatively large section 355 of the rotor, which can help accommodate the keyway 340.

[0038] In some embodiments, the motor 310 can be a double-pole motor. Generally, permanent magnets can be arranged in a double-pole motor to help maximize magnetic flux in two opposite directions relative to the rotor. For example, as in Fig. As shown in Figure 5A, permanent magnets can be arranged such that a first magnetic flux 501 and a second magnetic flux 502 are located in opposite directions relative to each other across the rotor 514. In some embodiments, as shown in Fig. As shown in Figure 5B, a motor can comprise two permanent magnets 550a, 550b positioned on opposite sides relative to a rotor 514 and arranged parallel to each other, such that a first magnetic flux 503 provided by the permanent magnet 550a and a second magnetic flux 404 provided by the permanent magnet 550b are opposite to each other.

[0039] In general, when four permanent magnets, e.g. the four permanent magnets 350a-d, are used in a double-pole motor, the permanent magnets can be designed to generate magnetic fluxes similar to what is done in Fig. 5A is shown. Two of the permanent magnets 350a-350d (e.g., permanent magnets 350a and 350c, permanent magnets 350b and 350d) can be positioned relatively close to each other to form two magnet groups, each of which can provide a magnetic flux. The magnetic flux provided by each of the magnet groups can be in opposite directions to each other. The angle α can be designed to be as close as possible to 180 degrees, so that each of the magnet groups has an effect from one magnet (such as magnets 550a, 550b as shown in Figure 5A). Fig. 5B) mimics this configuration. This configuration can help maximize the magnetic flux provided by each of the magnet groups (e.g., the magnet group comprising permanent magnets 350a and 350c and the magnet group comprising permanent magnets 350b and 350d).

[0040] Referring to Fig. In the 3D figure, which shows a side cross-sectional view of the rotor 314, the rotor 314 can comprise a lamination stack section 370 flanked by a first end section 371a and a second end section 371b. The lamination stack section 370 can generally comprise a plurality of laminations packed together along length L3. The first end section 371a and the second end section 371b flanking the lamination stack section 370 can be configured to include a mechanism to help retain components, such as the counterweight 330b and / or the shaft 316. In the illustrated embodiment, the first and second end sections 371a and 371b include a recessed structure configured to accommodate the counterweight 330b. The central bore 315 extends through the entire lamination stack section 370.

[0041] As in Fig. Magnets 350 (e.g., magnets 350a, 350b, 350c or 350d) can be represented in 3D. Fig. 3B) be embedded along the entire length (i.e., length L3) of the lamination stack section 370. In the illustrated embodiments, two separate magnets 350 can be aligned end-to-end along length L3, and it is clear that in some embodiments the length of one magnet 350 can be approximately the entire length L3 of the lamination stack section 370. The use of two separate magnets 350 can be helpful in assembling the rotor, since the magnet 350 can be embedded in the lamination stack section 370 from either end, the first end 371a and the second end 372b.

[0042] Referring to Fig. Figure 3E shows the lower section of the motor 310. After assembly, the alignment tongue 332 of the counterweight 330b is aligned in the keyway 340. The counterweight 330b is received by the cup-shaped second end 371b of the rotor 314. The counterweight 330b is held at one end 316b of the shaft 316 and rests on the second end 371b of the rotor 314.

[0043] In some embodiments, the counterweight 330b may be made of a material comprising iron. It is generally desirable that the iron-containing counterweight 330b not be in contact with the permanent magnets 350 embedded in the rotor 314. As in Fig. As shown in Figure 3E, when the counterweight 330b rests on the second end 371b of the rotor 314, the counterweight 330b can be separated from the lamination pack section 370 by a space 360, which can help to prevent the counterweight 330b from contacting the lamination pack section 370.

[0044] In some other embodiments, such as in Fig. As shown in Figure 4, a lamella pack section 470 of the rotor 414 can be covered by a separating plate 475 from the end section 471. The separating plate 475 can be made of a non-magnetic material, such as plastic. Referring to Fig. The separating plate 475 can be used to prevent the counterweight 330b from directly contacting the lamella pack section 370 of the rotor 314. Because of the separating plate 475, space 360 ​​is not required. Aspects

[0045] Each of aspects 1-7 can be combined with each of aspects 8-16. Each of aspects 8-14 can be combined with each of aspects 15-16. Aspect 1. A compressor of an HVAC system, comprising: a motor comprising a rotor, the rotor comprising a laminated core section; a large number of permanent magnets embedded in the laminated section of the rotor; a wave; a counterweight attached to the shaft; wherein the counterweight is separate from the permanent magnets, the rotor has a central bore with a flank, the shaft has a step, the shaft has a diameter larger than a diameter of the central bore, the step rests on the flank of the central bore, the counterweight and the step are positioned at opposite ends of the central bore, the counterweight has an interference fit with the shaft, and the step and the counterweight hold the shaft in the central bore of the rotor. Aspect 2. The compressor of aspect 1, wherein the central bore has a keyway, the shaft has a key and the key is fitted into the keyway. Aspect 3. The compressor of aspect 2, wherein the counterweight has an alignment tongue, the alignment tongue is positioned in the keyway. Aspect 4. The compressor of aspects 1-3, further comprising a separating plate designed to separate the permanent magnets from the counterweight. Aspect 5. The compressor of aspects 1-4, wherein the shaft and the central bore have an interference fit. Aspect 6. The compressor of aspect 5, wherein the shaft is shrink-fitted into the central bore. Aspect 7. The compressor of aspects 1-6, where an angle between adjacent magnets of the multitude of permanent magnets is not equal to 90 degrees. Aspect 8. A motor for an HVAC compressor, comprising: a rotor, the rotor comprising a lamella pack section; a large number of permanent magnets embedded in the laminated section of the rotor; a wave; a counterweight attached to the shaft; wherein the counterweight is separated from the permanent magnets, the rotor has a central bore with one flank, the shaft has a step, the step rests on the flank of the central bore, the counterweight and the step are positioned at opposite ends of the central bore, the counterweight has an interference fit with the shaft, and the step and the counterweight hold the shaft in the central bore of the rotor. Aspect 9. The motor of aspect 8, wherein the central bore has a keyway, the shaft has a key and the key is fitted into the keyway. Aspect 10. The motor of aspect 9, wherein the counterweight has an alignment tongue, the alignment tongue is positioned in the keyway. Aspect 11. The motor of aspects 8-10, further comprising a separating plate designed to separate the permanent magnets from the counterweight. Aspect 12. The motor of Aspects 8-11, wherein the shaft and the center bore have an interference fit. Aspect 13. The motor of Aspects 8-12, wherein the shaft has a diameter larger than the diameter of the center bore, and the shaft is shrink-fitted into the center bore. Aspect 14. The motor of aspects 8-13, where an angle between adjacent magnets of the multitude of permanent magnets is not equal to 90 degrees. Aspect 15. A method for holding a shaft in a rotor, comprising: Providing a shaft with a section having a diameter larger than the diameter of a rotor's central bore; Inserting a section of the shaft into the central bore of the rotor until the section with a diameter larger than the diameter of the central bore rests on one flank of the central bore; and Attaching a counterweight to the shaft from one end of the central bore opposite the section with a diameter larger than the diameter of the central bore, until the counterweight rests on the rotor; the counterweight and the shaft have an interference fit. Aspect 16. The procedure of Aspect 15, wherein fitting a section of the shaft into the central bore of the rotor includes shrink-fitting the shaft into the central bore.

[0046] With reference to the preceding description, it is understood that modifications may be made to the details without departing from the scope of the present invention. The description and illustrated embodiments are intended to be considered merely exemplary, with the true scope and spirit of the invention being determined by the broad scope of the claims.

Claims

[1] A compressor (100) of a heating, ventilation and air conditioning (HVAC) system, comprising: a motor (110, 210, 310) comprising a rotor (114, 214, 314), the rotor (114, 214, 314) comprising a lamella pack section (370, 470); a plurality of permanent magnets (350) embedded in the lamination stack section (370, 470) of the rotor (114, 214, 314); a wave (116, 216, 316); a counterweight (230a, 230b, 33b) attached to the shaft (116, 216, 316); wherein the counterweight (230a, 230b, 33b) is separated from the permanent magnets (350), the rotor (114, 214, 314) has a central bore (215, 315) with a flank (211, 311), the shaft (116, 216, 316) has a step (217, 317), the shaft (116, 216, 316) has a diameter (D2) that is larger than a diameter (D3) of the central bore (215, 315), the step (217, 317) rests on the flank (211, 311) of the central bore (215, 315), the counterweight (230a, 230b, 33b) and the step (217, 317) at opposite ends the central bore (215, 315) are positioned, the counterweight (230a, 230b, 33b) has an interference fit with the shaft (116, 216, 316), wherein the central bore (315) has a keyway (340), the shaft (316) has a key (342) and the key (342) is fitted into the keyway (340), and wherein the counterweight (330b) has an alignment tongue (332), and the alignment tongue (332) is fitted into the keyway (340). [2] The compressor (100) of claim 1, further comprising a separating plate (475) configured to separate the permanent magnets (350) from the counterweight (230a, 230b, 330b). [3] The compressor (100) of claim 1, wherein the shaft (116, 216, 316) and the central bore (215, 315) have an interference fit. [4] The compressor (100) of claim 1, wherein the shaft (116, 216, 316) is shrink-fitted into the central bore (215, 315). [5] The compressor (100) of claim 1, wherein an angle (a, b) between adjacent magnets of the plurality of permanent magnets (350) is not equal to 90 degrees. [6] The compressor (100) of claim 1, wherein the angle (a, b) between adjacent magnets of two of the plurality of permanent magnets (350) is greater than 90 degrees and the angle (a, b) between two other of the plurality of permanent magnets (350) is less than 90 degrees. [7] The compressor (100) of claim 1, wherein the rotor (114, 214, 314) rests against the counterweight (230a, 230b, 330b). [8] A motor (110, 210, 310) for a heating, ventilation and air conditioning (HVAC) compressor (100), comprising: a rotor (114, 214, 314), the rotor (114, 214, 314) comprising a lamella pack section (370, 470); a plurality of permanent magnets (350) embedded in the lamination stack section (370, 470) of the rotor (114, 214, 314); a wave (116, 216, 316); a counterweight (230a, 230b, 330b) attached to the shaft (116, 216, 316); wherein the counterweight (230a, 230b, 330b) is separated from the permanent magnets (350), the rotor (114, 214, 314) has a central bore (215, 315) with a flank (211, 311), the shaft (116, 216, 316) has a step (217, 317), the step (217, 317) rests on the flank (211, 311) of the central bore (215, 315), the counterweight (230a, 230b, 330b) and the step (217, 317) are positioned at opposite ends of the central bore (215, 315), the counterweight (230a, 230b, 330b) has an interference fit with the shaft (116, 216, 316) having a central bore (315) having a keyway (340), the shaft (316) having a key (342) and the key (342) being fitted into the keyway (340), and the counterweight (330b) having an alignment tongue (332) and the alignment tongue (332) being fitted into the keyway (340). [9] The motor (110, 210, 310) of claim 8, further comprising a separating plate (475) configured to separate the permanent magnets (350) from the counterweight (230a, 230b, 330b). [10] The motor (110, 210, 310) of claim 8, wherein the shaft (116, 216, 316) and the central bore (215, 315) have an interference fit. [11] The motor (110, 210, 310) of claim 8, wherein the shaft (116, 216, 316) has a diameter (D2) that is larger than a diameter (D3) of the central bore (215, 315), and the shaft (116, 216, 316) is shrink-fitted into the central bore (215, 315). [12] The motor (110, 210, 310) of claim 8, wherein an angle (a, b) between adjacent magnets of the plurality of permanent magnets (350) is not equal to 90 degrees. [13] The motor (110, 210, 310) of claim 8, wherein an angle (a, b) between adjacent magnets of two of the plurality of permanent magnets (350) is greater than 90 degrees and the angle (a, b) between two other of the plurality of permanent magnets (350) is less than 90 degrees. [14] The motor (110, 210, 310) of claim 8, wherein the rotor (114, 214, 314) rests against the counterweight (230a, 230b, 330b). [15] A method for holding a shaft (116, 216, 316) in a rotor (114, 214, 314), comprising: Providing a shaft (116, 216, 316) with a section having a diameter (D2) that is larger than the diameter (D3) of a central bore (215, 315) of a rotor (114, 214, 314); Inserting a section of the shaft (116, 216, 316) into the central bore (215, 315) of the rotor (114, 214, 314) until the section with a diameter (D2) larger than the diameter (D3) of the central bore (215, 315) rests on a flank (211, 311) of the central bore (215, 315); and Attaching a counterweight (230a, 230b, 330b) to the shaft (116, 216, 316) from one end of the central bore (215, 315) opposite the section with diameter (D2) larger than diameter (D3) of the central bore (215, 315); Fitting a wedge (342) into a keyway (340) of the central bore (215, 315); and Fitting an alignment tongue (332) of the counterweight (230a, 230b, 330b) into the keyway (340); wherein the counterweight (230a, 230b, 330b) and the shaft (116, 216, 316) have an interference fit. [16] The method of claim 15, comprising fitting a section of the shaft (116, 216, 316) into the central bore (215, 315) of the rotor (114, 214, 314) and shrink-fitting the shaft (116, 216, 316) into the central bore (215, 315). [17] The method of claim 15, comprising attaching the counterweight (230a, 230b, 330b) to the shaft (116, 216, 316) from the end of the central bore (215, 315) opposite the section with a diameter larger than the diameter of the central bore (215, 315), and bringing the counterweight (230a, 230b, 330b) and the rotor (114, 214, 314) together.

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