Abstract
The present invention relates to a lubricating oil transport system in a compressor, in which: the rotating shaft (3) has at least one concavity (35) that extends over part of the rotating surface (33) in contact with the internal surface (11) of the rotor (1) and at least one restrictor hole (34) that communicates with the internal region of the rotating shaft (3) and with the concavity (35); the rotor (1) comprises a circumferential channel (12) and at least one radial channel (13) extending through the inner wall (11) of the rotor (1); the radial channel (13) is arranged around the circumferential channel (12); said circumferential channel (12) and the radial channel (13) communicating with the concavity (35); the circumferential channel (12), the radial channel (13) and the concavity (35) transport oil for cooling the upper part of the rotor (1) and the stator (2).
Claims
1. System for transporting lubricating oil in a compressor, comprising: a housing; an electric motor comprising a rotor and a stator, the rotor comprising at least one inner wall; an oil pump and an oil reservoir arranged inside the housing; a rotating shaft as an integral part of the electric motor; a compressor block configured to house, at least partially, the rotating shaft; the rotating shaft supported by at least one radial bearing; the rotating shaft comprising a lower region, an upper region and a rotating surface; wherein the rotating shaft has at least one concavity that extends over part of the rotating surface in contact with the internal surface of the rotor and at least one restrictor hole which communicates with the internal region of the rotating shaft and with the concavity; the rotor comprises a circumferential channel and at least one radial channel extending through the inner wall of the rotor; the radial channel is arranged around the circumferential channel; the circumferential channel and the radial channel communicating with the concavity; the circumferential channel, the radial channel and the concavity configured to transport oil for cooling the upper part of the rotor and the stator.
2. System for transporting lubricating oil in a compressor, according to claim 1, wherein the concavity has a helicoid shape.
3. System for transporting lubricating oil in a compressor, according to claim 1, wherein the circumferential channel has an external diameter smaller than the external diameter of the rotating shaft housing in the compressor block.
4. System for transporting lubricating oil in a compressor, according to claim 1, wherein the radial channel outlet is inscribed in a circle with a diameter larger than the outer diameter of the rotating shaft housing in the compressor block.
5. System for transporting lubricating oil in a compressor, comprising: a housing; an electric motor comprising a rotor and a stator, the rotor comprising at least one inner wall; an oil pump and an oil reservoir arranged inside the housing; a rotating shaft as an integral part of the electric motor; a compressor block capable of housing, at least partially, the rotating shaft; the rotating shaft supported by at least one radial bearing; the rotating shaft comprising a lower region, an upper region and a rotating surface; wherein the rotor has at least one radial channel arranged around a circumferential channel; wherein the circumferential channel extends over at least part of the inner wall of the rotor; wherein the circumferential channel is located at an intermediate level between the upper part of the oil pump and the lower region of the rotating shaft; wherein the circumferential channel and the radial channel carry oil for cooling the upper part of the rotor and the stator; and wherein there is a partial juxtaposition between the entrance of the radial channel and the outer diameter of the circumferential channel.
6. The system according to claim 1 or claim 5, wherein the rotor is configured for an asynchronous induction motor, and wherein the radial channels and circumferential channel are formed by stacking a plurality of magnetic steel laminations, each lamination being rotated by a composite angle relative to the preceding lamination, wherein the composite angle comprises a lamination skew angle , based on a skew angle defined by the greater of the stator slot pitch and rotor slot pitch, and an interlock angle , defined by the number and arrangement of rotor bars, and wherein the number of radial channels nr is selected as an integer near to 360 divided by .
7. The system according to claim 6, wherein each lamination includes circular cutouts equally spaced around the circumferential channel, the circular cutouts configured such that, when the laminations are stacked and angularly aligned, the circular cutouts form continuous radial channels extending radially outward from the circumferential channel toward the rotor periphery.
8. The system according to claim 6 or claim 7, wherein the stacking orientation of each lamination is always performed by rotating each lamination in the same angular direction as the skewed rotor bar slots, and the result arrangement will differ depending on the relationship between and : if >, the radial channel pitch visually appears to follow the same angular direction as the skewed rotor bar slots; and If <, although each lamination is still rotated in the same direction, the radial channel pitch visually appear stacked in the opposite angular direction relative to the skewed rotor bar slots.
9. The system according to claim 8, wherein the radial channel pitch is selected so the radial channels appear oriented opposite the rotor rotation direction, and wherein the radial channel pitch direction matches the pitch direction of the shaft concavity.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0058] The preferred embodiments of the present invention are described in detail based on the Figures listed below.
[0059] FIG. 1 illustrates a sectional view of the compressor illustrating the state of the art, with the conventional oil pumping system exclusively for the compressor bearings.
[0060] FIG. 2 illustrates a perspective view of a rotating shaft of the state of the art, with the oil pumping system exclusively for the compressor bearings.
[0061] FIG. 3 illustrates a sectional view of the first embodiment of the compressor showing the lubricating oil transport system including the arrangement for cooling the engine coils by the oil jet.
[0062] FIG. 4 illustrates a perspective view of the first embodiment of the rotor-rotating shaft set with the rotor in section to show the helical concavities external to the shaft and how they cooperate with the channels placed on the top of the rotor according to present invention.
[0063] FIG. 5 is another perspective of the first embodiment of the shaft-rotor set, with the rotor in horizontal section, to show the circumferential channel and the radial channels and how they cooperate with the end of the external helical concavities of the shaft according to the present invention.
[0064] FIG. 6 illustrates a perspective view of the first embodiment of the rotating shaft showing the concavities on the rotating surface according to the present invention.
[0065] FIG. 7 illustrates an anterior view of the first embodiment of the rotating shaft, with the helical concavities for cooling the motor at the bottom and the helical concavity for lubricating the bearings at the top of the rotating region of the shaft. It is also possible to see the restrictor hole for cooling the motor at the beginning of the helical cavity at the lower region of the shaft according to the present invention.
[0066] FIG. 8 illustrates a right-side view of the first embodiment of the rotating shaft, showing the oil feed hole of the helical concavity for lubricating the bearings in the top of the rotating region of the shaft according to the present invention.
[0067] FIG. 9 illustrates a posterior view of the first embodiment of the rotating shaft, with the helical concavities for cooling the motor at the bottom and the helical concavity for lubricating the bearings at the top of the rotating region of the shaft. It is also possible to see a second restrictor hole for cooling the motor at the beginning of a second helical cavity at the lower region of the shaft according to the present invention.
[0068] FIG. 10 illustrates a left side view of the first embodiment of the rotating shaft, showing the oil degassing hole for lubricating the bearings at the end of the shaft region with interface to the rotor according to the present invention.
[0069] FIG. 11 illustrates a top view of the first embodiment of the rotor showing the radial channels and the circumferential channel at the top and a vertical sectional view of the rotor, showing the internal configuration of the radial and circumferential channels of the rotor according to present invention.
[0070] FIG. 12 illustrates a perspective view of the second embodiment of the shaft-rotor set, without the need for upward helical concavities on the rotating shaft for motor cooling, but with the restrictor hole and a circumferential communication concavity with the rotor according to the present invention.
[0071] FIG. 13 illustrates a perspective view of the second embodiment of the rotating shaft with the configuration of the circumferential channel on the external surface of the rotating shaft according to the present invention.
[0072] FIG. 14 illustrates an anterior view of the second embodiment of the rotating shaft, with the circumferential channel for cooling the motor at the bottom and the helical concavity for lubricating the bearings at the top of the rotating region of the shaft. It is also possible to see the restrictor hole for cooling the motor in the middle of the circumferential channel at the lower region of the shaft according to the present invention.
[0073] FIG. 15 illustrates a right-side view of the second embodiment of the rotating shaft, showing the oil supply hole of the helical concavity for lubricating the bearings in the top of the rotating region of the shaft according to the present invention.
[0074] FIG. 16 illustrates a posterior view of the second embodiment of the rotating shaft, with the circumferential channel for cooling the motor at the bottom and the helical concavity for lubricating the bearings at the top of the rotating region of the axis. It is also possible to see a second restrictor hole for cooling the motor in the middle of the circumferential channel at the lower region of the shaft according to the present invention.
[0075] FIG. 17 illustrates a left side view of the second embodiment of the rotating shaft, showing the oil degassing hole for lubricating the bearings at the end of the shaft region with interface to the rotor according to the present invention.
[0076] FIG. 18 illustrates a top view of the second embodiment of the rotor, with upward radial channels and a sectional view, showing the internal arrangement of these channels according to the present invention.
[0077] FIG. 19 illustrates a perspective view of the third embodiment of the shaft-rotor set, without cavities in the shaft for cooling the motor, only with the restrictor hole for oil passage according to the present invention.
[0078] FIG. 20 illustrates a perspective view of the third embodiment of the rotating shaft, with only the restrictor hole for oil passage according to the present invention.
[0079] FIG. 21 illustrates an anterior view of the third embodiment of the rotating shaft with the restrictor hole at the bottom and the helical concavity for transporting oil to the bearings at the top of the rotating region of the axis according to the present invention.
[0080] FIG. 22 illustrates a right-side view of the third embodiment of the rotating shaft, showing the il supply hole of the helical concavity for lubricating the bearings in the top of the rotating region of the shaft according to the present invention.
[0081] FIG. 23 illustrates a posterior view of the third embodiment of the rotating shaft, with a second restrictor hole for cooling the motor at the bottom and the helical concavity for lubricating the bearings at the top of the rotating region of the shaft according to the present invention.
[0082] FIG. 24 illustrates a left side view of the third embodiment of the rotating shaft, showing the oil degassing hole for lubricating the bearings at the end of the shaft region with interface with the rotor according to the present invention.
[0083] FIG. 25 illustrates a top view of the third embodiment of the rotor, with a circumferential channel located at an intermediate height in relation to the restrictor hole of the rotating shaft and upward radial channels responsible for allowing the passage of oil for cooling the motor to the top of the rotor. A cross-sectional view is also presented to facilitate understanding of the internal configuration of the rotor according to the present invention.
[0084] FIG. 26 illustrates a sectional view of a compressor according to a fourth embodiment of the motor cooling system by oil jet, when the oil pump is coupled to the rotor according to the present invention.
[0085] FIG. 27 illustrates a perspective view of the fourth embodiment of the shaft-rotor-oil pump set, with a partial cut applied to the rotor illustrating its internal configuration and the relative position of the circumferential channel and ascending radial channels in relation to the rotating shaft and the oil pump according to the present invention.
[0086] FIG. 28 illustrates an anterior view of the fourth embodiment of the shaft-rotor-oil pump set, with a partial cut applied to the rotor illustrating its internal configuration and the relative position of the circumferential channel and ascending radial channels in relation to the rotating shaft and the oil pump. A detail is provided indicating the height h of the circumferential channel, now also responsible for defining the flow of oil diverted for cooling the motor coils according to the present invention.
[0087] FIG. 29 illustrates a horizontal section of the fourth embodiment of the shaft-rotor-oil pump set located immediately above the circumferential channel in the rotor, illustrating in detail an alternative configuration for the transition between the circumferential channel and the ascending radial channels, which can be added to suit the oil flow for cooling the motor coils according to the present invention.
[0088] FIG. 30A illustrates a top view of the rotor lamination in backward pitch according to the present invention.
[0089] FIG. 30B illustrates a top view of the rotor lamination in forward pitch according to the present invention.
[0090] FIG. 31 illustrates a cut perspective view of the rotor and the shaft according to the present invention, wherein the pitch of the radial channels is selected to oppose the rotor rotation direction.
[0091] FIG. 32 illustrates a cut perspective view of the rotor without the shaft according to the present invention, wherein the pitch of the radial channels is selected to oppose the rotor rotation direction.
[0092] FIG. 33 illustrates a top sectional view of the rotor and shaft illustrated in FIG. 31 according to the present invention, wherein it is possible to see a backward pitch configuration of the radial channels and shaft concavity relative to the shaft rotation direction.
DETAILED DESCRIPTION OF THE INVENTION
[0093] In accordance with the general objectives of the present invention, a lubricating oil transport system is provided in a hermetic compressor for cooling the upper coils of the electric motor in addition to the normal lubricating oil transport system for the bearings and moving parts, as shown in FIG. 3.
[0094] According to FIG. 4, the lubricating oil transport system of the present invention is defined by the fact that the rotating shaft 3 comprises at least one concavity 35, said concavity 35 extends over part of the rotating surface 33, and a restrictor hole 34, said hole 34 communicates the concavity 35 with the internal region of the rotating shaft 3. The concavity 35 and the restrictor hole 34 are responsible for diverting a portion of lubricating oil, coming from the oil pump 6, from the internal region of the rotating shaft 3.
[0095] Said concavity 35, in general, defines a type of recess formed in the rotating surface 33 of the rotating shaft 3, such concavity 35 being partially closed by the inner wall 11 of the rotor 1. Thus, for the lubricating oil be transported, the rotating surface 33 interacts with the inner wall 11 of the rotor 1, forming a type of pumping mechanism that operates by centrifugal force, depending on the operation of the compressor.
[0096] According to FIGS. 4 and 5, the rotor 1 further comprises a circumferential channel 12 and at least one radial channel 13 extending through the inner wall 11 of the rotor 1. Said circumferential channel 12 cooperates with the radial channel 13, equally distributing the flow of lubricating oil provided by the concavity 35, regardless of the angular position of the rotor 1 in relation to the rotating shaft 3 and, consequently, in relation to the concavity 35. According to FIG. 11, the maximum diameter of the circumferential channel 12 must be smaller than the minimum outer diameter of the rotating shaft 3 housing in the compressor block 4, in order to limit the vertical displacement of the rotating shaft 3-rotor 1 set in relation to the compressor block 4. On the other hand, the length of the radial channel 13 must be dimensioned in such a way that its outlet is inscribed in a larger diameter than the same external diameter of the rotating shaft 3 housing in the compressor block 4, in order to ensure unrestricted flow of oil through the space 41 formed between the aluminum ring 14 of the rotor 1 and the compressor block 4, even under conditions where the vertical clearance between the rotor 1 and the rotating shaft 3 housing in the block compressor 4 is too small.
[0097] In a first preferred embodiment, the concavity 35 has a helicoid shape, extending in a spiral over part of the rotating surface 33. The recess must open towards the circumferential channel 12. This circumferential channel 12 also communicates with at least one radial channel 13.
[0098] The number of concavities 35 and restrictor holes 34 depend on the cooling need of the stator 2, where the electric motor coils are housed. FIGS. 6 to 10 illustrate several views of the rotating shaft 3. Likewise, the number of radial channels 13 in the rotor must allow the free flow of oil into space 41 and in a way provide a symmetry of the rotor, in order to leave it balanced, as illustrated in FIG. 11.
[0099] In a second possible embodiment, illustrated in FIGS. 12 to 17, the concavity 35 has an annular shape, extending around the rotating surface 33. In this configuration, at least one upward radial channel 13 is provided in the inner wall 11 of the rotor 1 which communicates with the concavity 35 of the rotating shaft 3. In this case, the rotor 1 may or may not have the circumferential channel 12 on its inner wall. FIG. 12 illustrates the rotor 1 provided with only the radial channel 13. The restrictor hole 34 is responsible for diverting part of the oil pumped by the pump 6 to the annular concavity 35, said concavity 35 makes the distribution of this oil flow until it finds the upward radial 13 channel, exiting into space 41 and finally being thrown against the coils of stator on the top of the electric motor. In addition, FIG. 18 illustrates the configuration of the rotor 1 for carrying out this second embodiment.
[0100] In a third alternative embodiment, illustrated in FIGS. 19 to 25, there is no concavity 35 on the rotating surface 33, only the restricted hole 34 remaining for communication with the internal part of the rotating shaft 3. In this embodiment, at least one longitudinal channel 13a is provided on the inner wall 11 of the rotor 1, said longitudinal channel 13a communicating with the circumferential channel 12 located at a height of the rotor 1 at the same level as the restrictor hole 34. Said circumferential channel 12, provided on the inner wall of the rotor 1, ensures that a specific angular positioning of rotor 1 with rotating shaft 3 is not necessary in order to align the restrictor hole 34 with the radial channel 13. FIG. 26 illustrates rotor 1 in this third embodiment.
[0101] In any constructive situation of the rotor 1, preferably two or more radial channels 13 are applied to the inner wall 11, said channels 13 disposed in order to guarantee the symmetry of the rotor 1 and avoid problems of unbalance. These radial channels 13 can and should follow the rotation angle of the aluminum bars of the rotor 1 cage and being obtained directly from the stamping of the rotor 1 blades.
[0102] The previous embodiments can be applied to compressors whose oil pump 6 is mounted by internal or external interference to the lower region 31 of the rotating shaft 3, or even by interference in relation to the internal wall 11 of the rotor 1, the deviation of oil for cooling the coil being carried out by the restrictor hole 34 provided on the rotating shaft 3.
[0103] A fourth embodiment is illustrated in FIG. 26. This embodiment is only used in hermetic compressors in which the oil pump 6 is mounted by interference in relation to the internal wall 11 of the rotor 1. In this embodiment, the rotating shaft 3 does not need the restrictor hole 34, which can remain with the original oil pumping system. In this way, the oil diversion for cooling the motor coils takes place in a section of the inner wall 11 between the upper part of the oil pump 6 and the lower region 31 of the rotating shaft 3, through a circumferential channel 12. The channel circumferential has a height h, illustrated in FIG. 28. This circumferential channel 12 communicates with at least one upward longitudinal channel 13a, which takes this oil flow into space 41 and, subsequently, to the coils located at the top of stator of the electric motor, as shown in FIG. 27.
[0104] The circumferential channel 12 can be obtained directly by stacking sheets of electric steel. However, this will cause the height h to be an integer multiple of the thickness of the blade of the electric rotor steel. If this height h results in an oil flow deviated for the cooling of the electric motor coils that affects the flow required for the lubrication of the radial bearings 5a and 5b, for example, an additional restriction can be provided by the partial juxtaposition of the outside diameter of the circumferential channel 12 with the diameter of the upward longitudinal channel 13a, as represented by the dimension dr in the detail of FIG. 29.
[0105] In a further aspect of the invention, in which the rotor is configured for an asynchronous induction motor, the radial channels 13 and the circumferential channel 12 are formed by stacking a plurality of stamped magnetic steel laminations. Each lamination includes a pattern comprising a central region that defines the circumferential channel 12 and several circular cutouts positioned radially said circumferential channel 12. When stacked, these circular cutouts align to form radial channels 13, which serve as oil conduits extending from the circumferential channel 12 toward the rotor periphery.
[0106] To properly align the bar slots and maintain mechanical symmetry, each rotor lamination in the stack is rotated by a composite angle relative to the one beneath it. The rotation angle is defined as the sum of: (i) a lamination skew angle , based on a skew angle defined by the greater of the stator slot pitch and rotor slot pitch, and (ii) an interlock angle , based on the number and arrangement of rotor bars to compensate for lamination slit asymmetries. Skew and interlock angles are well-known design parameters in rotor lamination for induction motors. The lamination skew angle is employed to reduce cogging torque and acoustic noise during motor operation. The interlock angle is used to compensate for geometric asymmetries introduced during the stamping process and helps ensure optimal rotor stack straightness. These angles are commonly combined to define the total rotation angle applied between successive laminations during rotor assembly. As such, the specific calculation methods and construction techniques associated with skew and interlock angles need not be detailed herein.
[0107] For example, for a rotor stack height of 47.5 mm using laminations of 0.5 mm thickness, and a skew angle =15, the lamination skew angle is calculated as =150.5/47.5=0.1579. If the rotor has 28 bars and an interlock index k=3, the interlock angle becomes =3603/28=38.5714. The final rotation per lamination is thus =+=38.7293.
[0108] The number of radial channels nr is selected to be an integer close to 360/ to ensure uniform distribution and symmetry, optimizing cooling performance and mechanical balance of the rotor. For the example above, 360/9.3, so nr may be selected as either 9 or 10. In this context, the angle between adjacent radial channels 13 is defined as =360/nr. Therefore, the radial channels 13 are ideally spaced every 40 (for nr=9, as illustrated in FIG. 30B) or 36 (for nr=10, as illustrated in FIG. 30A).
[0109] The stacking orientation of each lamination is always performed by rotating each lamination in the same angular direction as the skewed rotor bar slots, as such, the radial channel pitch is always the same as the skewed rotor bar slots. However, depending on the relationship between and , the resulting arrangement of the radial channel pitch will visually differ:
[0110] If >, the radial channel pitch visually appears to follow the same angular direction as the skewed rotor bar slots, defining a forward pitch configuration (FIG. 30B).
[0111] If <, although each lamination is still rotated in the same direction, the radial channel pitch visually appears stacked in the opposite angular direction relative to the skewed rotor bar slots, defining a backward pitch configuration (FIG. 30A).
[0112] Thus, as used herein, the term forward pitch refers to a configuration in which the radial channels have the same apparent pitch direction as the skewed rotor bar. Conversely, the term backward pitch refers to a configuration wherein the radial channels visually appear oriented in the opposite angular direction compared to the skewed rotor bars, even though each lamination is consistently rotated in the same rotational direction during assembly.
[0113] As illustrated in FIGS. 31 and 32, preferably, the radial channel pitch is selected such that the radial channels appear oriented opposite to the rotor rotation direction in order to enhance oil dispersion. Additionally, the radial channels 13 are preferably designed to have the same pitch direction as the shaft concavity 35, so that the oil flow guided by the shaft concavity 35 can seamlessly continue into the radial channels 13, as illustrated in FIG. 33. This alignment improves the continuity of the oil path from the shaft to the stator cooling zone.
[0114] It is important to note that the above descriptions have the sole purpose of describing in particular exemplary embodiments of the present invention.
