Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
  • F04B39/02—Lubrication
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
  • F04B39/0094—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00 crankshaft
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
  • F04B39/02—Lubrication
  • F04B39/0223—Lubrication characterised by the compressor type
  • F04B39/023—Hermetic compressors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
  • F04B39/02—Lubrication
  • F04B39/0223—Lubrication characterised by the compressor type
  • F04B39/023—Hermetic compressors
  • F04B39/0238—Hermetic compressors with oil distribution channels
  • F04B39/0246—Hermetic compressors with oil distribution channels in the rotating shaft
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C39/00—Relieving load on bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C39/00—Relieving load on bearings
  • F16C39/06—Relieving load on bearings using magnetic means
  • F16C39/063—Permanent magnets

Definitions

• the present invention refers to an axial bearing arrangement in a reciprocating hermetic compressor with vertical shaft of the type used in small refrigeration systems.
• Hermetic compressors of refrigeration present, mounted inside a hermetically sealed shell a cylinder block, supporting a vertical crankshaft to which is mounted the rotor of an electric motor.
• the weight of the crankshaft-rotor assembly is supported by an axial bearing, generally in the form of a flat sliding axial bearing in which an oil film guarantees the separation of the surfaces with mutual relative movement (slipping) , or in the form of a roller bearing (US4632644; WO03/019008) in which a ball assembly supports the axial weight, rolling on races that resist the Hertz tensions developed by contact with the balls.
• the crankshaft carries, in its lower end, a pump rotor, which during the operation of the compressor conducts lubricant oil from a reservoir defined in the lower portion of the shell to the parts with mutual relative movement so as to guarantee oil supply for the correct operation of said parts.
• the position of the axial bearing may vary according to the arrangement of the compressor components and to design variations.
• the rotor is mounted to the crankshaft below the cylinder block, as illustrated in figure 1, or the rotor is mounted to the crankshaft above the cylinder block, as illustrated in figure 2.
• the surfaces that define the axial bearing are altered.
• the lower face of the annular flange can axially journal on an upper annular surface of said second radial bearing, as illustrated in figure 3 for a specific arrangement in which the rotor is mounted below the cylinder block.
• Co-pending document O03/019008 of the same applicant refers to a hermetic compressor having the rotor of the electric motor mounted to the crankshaft below the cylinder block and presenting a roller axial bearing arrangement which increases the mechanical reliability of the roller bearing by minimizing the effects of crankshaft deflection, as illustrated in figure 4.
• Objects of the Invention It is a generic object of the present invention to provide a bearing arrangement in a reciprocating hermetic compressor of refrigeration, which can reduce mechanical losses and total noise levels, resulting in better energetic performance of the hermetic compressor.
• the present bearing arrangement is applied to a reciprocating hermetic compressor, comprising: a cylinder block mounted inside a shell and carrying a cylinder and a vertically disposed radial bearing hub; a crankshaft mounted through the radial bearing hub and having a first end portion projecting outwardly from the radial bearing hub and securing a rotor of an electric motor, and an opposite second end portion projecting outwardly from the radial bearing hub and incorporating a peripheral flange and an eccentric portion, the arrangement of the present invention comprising at least one magnetic axial bearing assembly composed of magnet elements with mutually confronting faces and with magnetic orientation to produce in a normal operation, support for the crankshaft sufficient to guarantee the inexistence of contact between the confronting faces of the magnet elements that define the axial bearing, each magnet element being mounted in a respective part associated with a rotating component (crankshaft or any component rigidly connected thereto, such as the rotor) , and the other part being associated with a fixed component (cylinder block or any component rigidly connected there
• Figure 1 is a median vertical sectional view of a reciprocating hermetic compressor with the vertical crankshaft affixed to an electric motor rotor disposed below the cylinder block and vertically supported by a prior art axial bearing;
• Figure 2 is a view similar to that of the previous figure, but illustrating a prior art construction in which the rotor of the electric motor is positioned above the cylinder block and vertically supported by a prior art roller axial bearing;
• Figure 3 is a median vertical sectional view of a reciprocating hermetic compressor similar to that of figure 1 and which is provided with an external bearing actuating radially on an extension of the crankshaft external to its eccentric portion and vertically supported by an axial bearing;
• Figure 4 is a partial vertical sectional view of a cylinder block of the type illustrated in Figure 1 and incorporating a vertical radial bearing hub, in whose upper end a roller axial bearing is seated to the crankshaft-electric motor rotor assembly, as taught in the prior art ;
• Figure 5 is an enlarged and partial vertical sectional view of a cylinder block of the type shown in figure 1 and incorporating a radial bearing hub which is designed to receive a magnetic axial bearing element and an oil deflecting means constructed according to the present invention;
• Figure 6 is an enlarged and partial vertical sectional view of a cylinder block of the type illustrated in figure 1, showing another construction of the oil deflecting means of the present invention;
• Figure 7 is a perspective view of the deflecting means
• FIG 8 is an enlarged view of the mounting arrangement of the magnets illustrated in figures 5 and 6, according to the present invention. Detailed Description of the Invention
• Figure 1 illustrates, in a simplified way, a reciprocating hermetic compressor comprising a shell 10 within which is appropriately suspended a cylinder block 20, defining a cylinder 30 and incorporating a radial vertically disposed bearing hub 40 rotatively supporting a vertical crankshaft 50, having a first end portion projecting outwardly from the radial bearing hub 40 so as to secure a rotor 61 of an electric motor 60, whose stator 62 is secured under a cylinder block 20.
• the crankshaft 50 further presents a second end portion projecting outwardly from the radial bearing hub 40 and incorporating a peripheral flange 51, whose lower face defines an axial bearing annular surface 51a and an eccentric portion 52 to which is mounted the larger eye of a connecting rod 70, whose smaller eye is mounted to a piston 80 reciprocating inside the cylinder 30.
• FIG. 1 further illustrates a reciprocating hermetic compressor with the same basic elements already described in relation to the compressor of figure 1 and which are represented by the same reference numbers.
• the electric motor 60 is disposed above the cylinder block 20 and consequently above the radial bearing hub 40.
• FIG 3 further illustrates a reciprocating hermetic compressor with the same basic elements already described in relation to the compressor of figure 1 and which have the same reference numbers.
• an external bearing 120 is seated on the cylinder block 20 and provided so as to actuate radially on the eccentric portion 52 of the crankshaft 50.
• the same compressor configuration can be found when the electric motor 60 is disposed above the cylinder block 20.
• a roller axial bearing arrangement is illustrated, which is applied to a reciprocating hermetic compressor with its crankshaft 50 being vertically disposed and carrying a rotor 61 of an electric motor mounted below the cylinder block 20 and the radial bearing hub 40.
• a magnetic bearing arrangement comprising at least one magnetic axial bearing assembly 100 composed of at least one pair of mutually confronting magnet elements 101, each magnet element 101 being mounted to a respective part of at least one of the pairs of parts of crankshaft 50 and cylinder block 20 and of cylinder block 20 and rotor 61 and there being provided, to at least one of the pairs of parts, confronting mechanical stops which are maintained spaced from each other by an axial gap FA smaller than a magnetic axial gap FM existing between the confronting faces of the magnet elements 101 so as to guarantee that, upon occurring at least one of the conditions of a sufficiently high increase of the compressor temperature and an axial displacement of said parts during transportation of the compressor, causing the mutual seating of the confronting mechanical stops, the magnetic axial gap is maintained higher than zero.
• the magnet elements 101 are provided between an extension of the crankshaft 50 external to the eccentric portion 52, and the external bearing 120.
• Each magnet element 101 can be formed of one or more magnet portions, for example annular portions dimensioned so as to complete a closed ring in a circumferential arrangement .
• at least one magnetic axial bearing assembly 100 is formed of axially superposed magnetic rings.
• At least one magnet element 101 is formed in a single piece.
• the magnet elements 101 present a magnetic orientation to produce a support of the crankshaft 50 which is sufficient to guarantee the inexistence of contact between the confronting surfaces of the magnet elements which define the magnetic axial bearing, the magnet elements being mounted in pairs of support surfaces, one of these support surfaces of each pair being associated with the rotating component
• the magnet elements 101 are mounted between the axial surfaces of components with mutual relative movement, so that the latter support the axial load of the crankshaft 50/rotor 60 assembly of the electric motor 60 preventing said axial surfaces of the components with mutual relative movement (crankshaft 50 and cylinder block 10 and/or cylinder block 20 and rotor 61 and/or crankshaft 50 and external bearing 120) as well as any surfaces of the magnet elements 101 from contacting during part or the whole operating time of the compressor.
• the axial force exerted on the magnetic axial bearing assembly 100 is practically constant and of low magnitude (around 12. ON) , which allows using magnets of small mass (around 1.0 to 2. Og) consequently of an acceptable cost.
• Both the dimensioning of the magnets and the selection of the materials should be such as to guarantee the lowest variation of the magnetic axial gap FM between the magnet elements 101 caused by temperature variation.
• At least one of the stop surfaces defines an annular sliding bearing disposed around the crankshaft 50, at least one of said stop surfaces being incorporated to one of the parts of crankshaft 50 and cylinder block 20, of cylinder block 20 and rotor 61, or crankshaft 50 and external bearing 120.
• a magnet element 101 of a magnetic axial bearing assembly 100 is seated on a lowered portion of an end of the radial bearing hub 40, the other magnet element 101 thereof being seated against an adjacent surface portion of the peripheral flange 51, said radial bearing hub 40 defining a stop surface, and the peripheral flange 51 defining the other stop surface of the pair of said stop surfaces, said stop surfaces being disposed radially internally in relation to said pair of magnet elements 101 and having their axial gap FA axially leveled with the magnetic axial gap FM of said pair of magnet elements
• said lowered portions guide the assembly of the magnet elements 101, defining housings for the latter, which lowered portions can, for example, retain or guide each said magnet element 101 by their respective internal diameters, which facilitates the machining process of these housings.
• at least one magnet element 101 is retained to one of said parts of crankshaft 50 and cylinder block 20 and cylinder block 20 and rotor 61, or crankshaft 50 and external bearing 120, by at least one of the radially internal, radially external and end faces thereof.
• the retention of each magnet element 101 to the respective part could be carried out by any securing means, as long as it guarantees the concentricity of said magnet elements 101 in relation to the rotating shaft of the crankshaft 50.
• each lowered portion is calculated so as to assure that, even considering the dimensional variations of the magnet elements 101, the magnetic axial gap FM therebetween when mounted, is larger than the axial gap FA defined between the confronting stop surfaces where the lowered portions are located, guaranteeing that, under operation or in a transportation condition no impact will occur between the confronting magnet elements 101, neither between these and the other surfaces other than those involving each magnet element 101 in the respective lowered portion.
• each lowered portion preferably guides the respective magnet element 101 by the external diameter thereof .
• at least one of the stop surfaces is defined by an insert which is secured to and projects from one of said parts of crankshaft 50 and cylinder block 20, of cylinder block 20 and rotor 61, or of crankshaft and external bearing 120, said insert being for example a pin mounted by interference to one of said parts.
• the crankshaft 50 presents, externally, at least one helical groove in its external surface, defining a respective superficial oil channel 53 through which the lubricant oil stored in the bottom of the shell 10 is upwardly pumped.
• the superficial oil channel 53 presents an oil inlet lower end (not illustrated) in fluid communication with the lubricant oil inside the shell 10, and an oil outlet upper end 53a opened to the lower end of an inclined axial oil channel 54 provided along the eccentric portion 52 and which conducts lubricant oil to an end face of said eccentric portion 52.
• the bearing arrangement of the present invention comprises a deflecting means carried by the crankshaft 50 itself and which is disposed so as to conduct to the interior of the oil channel 54, most of the ascending oil flow reaching the oil outlet upper end 53a of the superficial oil channel 53, minimizing the centrifugal radial escapes of said ascending oil flow in the region of the adjacent end of the radial bearing hub 40.
• the deflecting means makes that part of the radial oil flow received therein to be forced to flow upwardly, penetrating in the oil channel 54 by its radially and axially opened lower portion and being elevated till the top of the eccentric portion 52.
• Figures 5 and 6 illustrate a first embodiment for the bearing arrangement of the present invention which prevents the oil from leaking between the magnet elements 101 disposed between the parts of crankshaft 50 and cylinder block 20.
• the deflecting means is in the form of a conduct 110 disposed inside the oil channel 54, having an end 111 opened to the oil outlet upper end 53a of the superficial oil channel 53 and an opposite end 112 opened to the inside of the internal oil channel 54, the end 111 being axially spaced from a lower plane of the magnetic axial gap FM between said magnet elements 101.
• the former For mounting the conduct 110 inside the oil channel 54, the former carries, in its opposite end 112, an expanding portion 113 in the form of an arc which is resiliently forced to a compressing condition so as to mount the conduct 110 inside the oil channel 54, said condition being maintained by the seating of an external surface of said expanding portion 113 against an internal surface of the oil channel 54.
• the deflecting means is defined by an axial wall portion 55 of the crankshaft 50, provided between the oil outlet upper end 53a of the superficial oil channel 53 and the lower end of the oil channel 54 of the eccentric portion 52, said axial wall portion 55 extending along the crankshaft 50 at least in the region of the adjacent end of the radial bearing hub 40.
• the oil channel 54 has part of its extension provided inside the crankshaft 50.
• the present arrangement further comprises an oil passage 56 defined inside the crankshaft 50 and which is internal to and spaced from the peripheral contour of the latter, having an upper end portion opened to the upper end of the oil channel 54 and a lower end portion opened to the oil outlet upper end 53a of the superficial oil channel 53, the peripheral contour of at least one of the parts of oil passage 56 and oil channel 54 defining an internal contour for the axial wall portion 55.
• the minimum dimensions of the magnet elements 101 for a given magnetic material can present a very high supporting capacity, resulting in very large mechanical gaps (FA) and magnetic axial gaps (FM) .
• the adjustment of this supporting capacity of the magnet elements 101 can be obtained by mixing the magnetic material with polymers by processes, such as metal injection (injection molding) .

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Compressor (AREA)
• Sliding-Contact Bearings (AREA)
• Magnetic Bearings And Hydrostatic Bearings (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (7)

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• 2004
  • 2004-04-12 BR BR0401574-6A patent/BRPI0401574A/pt not_active IP Right Cessation
• 2005
  • 2005-04-11 KR KR1020067023488A patent/KR20060135068A/ko not_active Application Discontinuation
  • 2005-04-11 CN CNA2005800164710A patent/CN1997826A/zh active Pending
  • 2005-04-11 US US10/599,794 patent/US20070166175A1/en not_active Abandoned
  • 2005-04-11 EP EP05714415A patent/EP1740833A1/de not_active Withdrawn
  • 2005-04-11 WO PCT/BR2005/000048 patent/WO2005098236A1/en active Application Filing
  • 2005-04-11 JP JP2007507629A patent/JP2007532821A/ja not_active Withdrawn

Non-Patent Citations (1)

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