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
  • 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
  • F04B39/0005—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 adaptations of pistons
• • 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
  • F04B39/0005—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 adaptations of pistons
  • F04B39/0022—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 adaptations of pistons piston rods
• • 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
  • F04B39/12—Casings; Cylinders; Cylinder heads; Fluid connections
  • F04B39/122—Cylinder block
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B31/00—Compressor arrangements
  • F25B31/02—Compressor arrangements of motor-compressor units
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
  • F05B2210/00—Working fluid
  • F05B2210/10—Kind or type
  • F05B2210/14—Refrigerants with particular properties, e.g. HFC-134a
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S417/00—Pumps
  • Y10S417/902—Hermetically sealed motor pump unit

Definitions

• the present invention relates to a hermetic compressor used in a refrigerating cycle of a Refrigerator Freezer, etc.
• Fig. 7 is a longitudinal sectional view showing a general hermetic compressor described in US Patent No. 5,228,8435 and Fig. 8 is a perspective view showing a piston described in International Publication WO 02/02944.
• hermetic housing 1 houses motor element 4 consisting of stator 2 having winding portion 2a and rotor 3, and compression element 5 driven by motor element 4.
• crankshaft 10 includes main shaft 11 to which rotor 3 is press-fitted and fixed and eccentric shaft 12 formed eccentric to main shaft 11. Inside main shaft 11, oil pump 13 is housed and an opening portion of oil pump 13 is disposed in oil 6.
• Block 20 provided at the upper side of motor element 4 has cylinder 21 having a substantially cylindrical shape and bearing 22 for supporting main shaft 11.
• Piston 30 is inserted into cylinder 21 of block 20 capable of reciprocating sliding and coupled to eccentric shaft 12 via connecting means 41.
• a conventional piston is described with reference to Fig. 8.
• Piston 30 includes top surface 31, skirt surface 32 and outer circumferential surface 33. Furthermore, outer circumferential surface 33 includes seal surface 34, two guide surfaces 35 and removed portions 36.
• seal surface 34 is a surface in the circumferential direction, which is formed so as to be brought into close contact with the inner circumferential surface of cylinder 21.
• Guide surface 35 is formed so as to be brought into close contact with a part of the inner circumferential surface of cylinder 21 and extends substantially in parallel in the direction of the movement of piston 30.
• Removed portion 36 is a concave portion that is not brought into close contact with the inner circumferential surface of cylinder 21.
• an angle made by hnes respectively connecting between central axis 37 of cyhndrical piston 30 and two boundary edges 35a and 35b of guide surface 35 in the direction of the radius of piston 30 is generally 40° or less and preferably 30° or less.
• a conventional hermetic compressor shown in Fig. 7 is described.
• piston 30 reciprocates in the horizontal direction in the drawing. In the vicinity of the bottom dead center, a part of the skirt side of piston 30 is protruded to the outside of cylinder 21. From this state, when piston 30 enters cylinder 21, that it is to say, when piston 30 moves in the right direction of Fig. 7, piston 30 is guided by guide surface 35 and thereby can enter cylinder 21 smoothly.
• inclination in the vertical direction of piston 30 with respect to cylinder 21 is regulated by space between outer circumferential surface 33 and cylinder 21 only in short section 34A between the edge of top surface 31 and the edge of seal surface 34.
• piston 30 is likely to be inclined in the vertical direction.
• top surface 31 of piston 30 undergoes compression load of a refrigerant gas and furthermore, crankshaft 10 is pressed in the direction that is not the direction of a piston (downward direction in Fig. 7) via connecting means 41, and thereby the inchnation of piston 30 in the vertical direction is hkely to be increased.
• low-density refrigerant Isobutane (R600a) was used, the outer diameter of piston 30 was increased and leakage of refrigerant was likely to occur, and therefore the efficiency was lowered remarkably.
• a hermetic compressor of the present invention includes an under cut that does not communicate with at least a top surface of a piston on an outer circumferential surface of the piston excluding a shding surface provided in the axis direction and in the perpendicular direction of the piston pin, in which the under cut communicates with space inside a housing at least in the vicinity of the bottom dead center.
• the shding surface provided in the parallel and in the perpendicular direction of the piston pin the inchnation of the piston with respect to the cyhnder is suppressed, thus suppressing the leakage of refrigerant. Furthermore, by supplying the shding portion with oil through the under cut, the seahng property can be improved. With the above-mentioned effect, a hermetic compressor with high efficiency can be provided.
• Fig. 1 is a longitudinal sectional view showing a hermetic compressor in an exemplary embodiment of the present invention.
• Fig. 2 is an enlarged sectional view showing an element around a piston used for a hermetic compressor in an exemplary embodiment.
• Fig. 3 is a front view showing a piston used for a hermetic compressor in an exemplary embodiment.
• Fig. 4 is a sectional view of a part along line 4-4 of FIG. 3.
• Fig. 5 is an enlarged sectional view showing an end face of an under cut of a piston used for a hermetic compressor in an exemplary embodiment.
• Fig. 1 is a longitudinal sectional view showing a hermetic compressor in an exemplary embodiment of the present invention.
• Fig. 2 is an enlarged sectional view showing an element around a piston used for a hermetic compressor in an exemplary embodiment.
• Fig. 3 is a front view showing a piston used for a hermetic compressor in an exemplary embodiment.
• Fig. 4 is
• FIG. 6 is an enlarged sectional view showing a tip of a piston used for a hermetic compressor in an exemplary embodiment.
• Fig. 7 is a longitudinal sectional view showing a conventional hermetic compressor.
• Fig. 8 is a perspective view showing a piston used for a conventional hermetic compressor.
• Fig. 1 is a longitudinal sectional view showing a hermetic compressor in an exemplary embodiment of the present invention
• Fig. 2 is an enlarged sectional view showing an element around a piston!
• Fig. 3 is a front view showing a piston
• Fig. 4 is a sectional view of a part along hne 4-4 of FIG. 3;
• Fig. 5 is an enlarged sectional view showing an end face of an under cut of a piston, " and
• Fig. 6 is an enlarged sectional view showing a tip of a piston.
• housing 101 houses motor element 104 and compression mechanism 105 driven by motor element 104, and moreover contains oil 106.
• Motor element 104 includes stator 102 and rotor 103, and enables inverter driving by using a control circuit, etc. controlled at plural operational frequencies including operation frequency that is not higher than power supply frequency.
• the hermetic compressor of this exemplary embodiment uses hydrocarbon-based refrigerant Isobutane (or R600a).
• Refrigerant R600a is a natural refrigerant with low global warming potential.
• Crankshaft 110 includes main shaft 111 and eccentric shaft 112 and is disposed in substantially the vertical direction.
• rotor 103 is press- fitted and fixed to main shaft 111 and eccentric shaft 112 is disposed eccentric to main shaft 111.
• Oil supplying structure 120 includes centrifugal pump 122, vertical hole
• Block 130 includes substantially cylindrical cyhnder 131, main bearing
• Cyhnder 131 for supporting main shaft 111 and collision-portion 134 provided on the upper side of cyhnder 131.
• Cyhnder 131 includes notch 135 provided on the upper side of the edge at the side of crankshaft 110.
• Piston 140 is inserted into cyhnder 131 capable of reciprocating sliding. Piston 140 has piston pin hole 141 formed in parallel to the center axis of eccentric shaft 112. Into piston pin hole 141, hoUow cylindrical piston pin 142 is fitted. Piston pin 142 is fixed to piston 140 by hoUow cylindrical lock pin 143. Piston pin 142 is connected to eccentric shaft 112 via connecting rod 146. Hollow part 144 of piston pin 142 communicates with space inside housing 101 via vent hole 145.
• Fig. 4 is a sectional view of a part of piston 140 taken along hne 4-4 of FIG. 3, showing a state of cyhndrical central axis 170 of the piston seen from the left direction.
• under cut 153 is formed excluding a region with a predetermined width in parallel direction 147 with respect to the axis of piston pin 142 and a region with a predetermined width in the perpendicular direction 148 with respect to the axis of piston pin 142.
• Total area of under cut 153 is not less than one half of an area of outer circumferential surface 150 of the piston.
• angle ⁇ made by edge 180 of under cut 153 and outer circumferential surface 150 of the piston is set to be an acute angle.
• the right end portion of piston 140 is provided with circumferentiaUy formed land 190, on which under cut 153 is not formed, in a predetermined width from top surface 151.
• outer circumferential surface 150 that does not belong to any of circumferentiaUy formed land 190 and under cut 153 is referred to as axially formed land 192.
• axiaUy formed land 192 is provided in paraUel to cyhndrical central axis 170 and extends from circumferentiaUy formed land 190 and reaches skirt surface 152. As shown in Fig. 4, axiaUy formed lands 192 are formed in a predetermined width on an outer circumferential surfaces at 0°, 90°, 180° and 270° with respect to the cyhnder axis as a center. Furthermore, as shown in Fig.
• the width of axiaUy formed land 192 is set so that angle ⁇ made by two lines linking between cyhndrical central axis 170 of piston 140 and two boundary portions of axiaUy formed land 192 in the direction of radius of the piston is set to 40° or less and preferably 30° or less.
• angle ⁇ made by two lines linking between cyhndrical central axis 170 of piston 140 and two boundary portions of axiaUy formed land 192 in the direction of radius of the piston is set to 40° or less and preferably 30° or less.
• upper sliding surface 154 and lower sliding surface 155 are provided in the vertical direction and side shding surface 160 is provided in the direction of the side surface. These correspond to one or both of circumferentiaUy formed land 190 and axially formed land 192.
• circumferentiaUy formed land 190 two annular grooves 191 are provided in the outer circumferential direction of the piston. Furthermore, on outer circumferential surface 150 of the piston, at both end portions of top surface 151 side and skirt surface 152 side, minute tapers 201 and 202 are provided. In this exemplary embodiment, as shown in Fig. 1, in the vicinity of the bottom dead center, a part of the skirt side of piston 140 is protruded from cyhnder 131. With such a configuration, even in a shape in which under cut 153 does not reach skirt surface 152, under cut 153 is opened in space inside the housing when at least piston 140 is in the bottom dead center. Next, the operation and action of the hermetic compressor of the exemplary embodiment are described.
• Oil 106 which reached viscosity pump 121 further moves upwardly in viscosity pump 121 and are scattered in housing 101 via vertical hole 123 and lateral hole 124.
• OU 106 scattered in housing 101 coUides with coUision-portion 134 and moves along notch 135 so as to be attached to outer circumferential surface 150 of the piston. Attached oU 106 moves around outer circumferential surface 150, under cut 153, annular groove 191 and minute tapers 201 and 202 in accordance with the reciprocating movement of piston 140, and works as a lubricant between outer circumferential surface 150 and cyhnder 131.
• the hermetic compressor of this exemplary embodiment as shown in Fig.
• crankshaft 110 is pressed toward the opposite direction to the piston and may be inclined.
• piston 140 may be inchned in the vertical direction with respect to cyhnder 131, thereby forming a part in which space between cyhnder 131 and outer circumferential surface 150 of the piston may be broadened.
• leakage of a refrigerant gas from the part may be accelerated.
• the inchnation of piston 140 may deteriorate the lubricant state between piston 140 and cyhnder 131 and may increase a sliding noise.
• the shding loss generated when piston 140 reciprocates in cyhnder 131 is in a state of fluid lubricant in which the loss is reduced in proportion to reduction of the shding area.
• the area of under cut 153 is set to not less than one half of the area of outer circumferential surface 150 of the piston, shding loss of piston 140 is about one half.
• high efficiency by remarkable input reduction can be reahzed.
• a high pressure gas inside cyhnder 131 leaks out to under cut 153.
• under cut 153 always communicates with space inside housing 101 at skirt surface 152 side, leaked refrigerant gas is not accumulated in under cut 153.
• under cut 153 may be allowed to communicate with space inside housing 101 only in the vicinity of the bottom dead center, or under cut 153 may be aUowed to communicate with piston pin hole 141.
• circumferentiaUy formed land 190 is provided with annular groove 191 and oU 106 is aUowed to be brought into direct contact with annular groove 191 in the vicinity of the bottom dead center in which piston 140 is protruded from cyhnder 131, attached oU 106 is spread over the entire part of annular groove 191 by the capUlary phenomenon.
• minute tapers 201 and 202 provided at the end portions both at top surface 151 side and skirt surface 152 side of piston 140 is described.
• oU 106 moves around circumferentiaUy formed land 190 of piston 140 so as to improve the lubricant property of piston 140 and to also improve the seahng property.
• piston 140 moves from the top dead center to the bottom dead center, by the wedge effect of minute taper 202 at the skirt surface 152 side, oU 106 enters minute taper 202 so as to form an oU film and lubricant property and seahng property are improved.
• the presence of minute tapers 201 and 202 suppresses the leakage of refrigerant and reduces the shding loss. Furthermore, high efficiency can be achieved. Furthermore, in the case where the motor element is inverter- driven at plural operation frequencies including operation frequency that is not more than power supply frequency, reciprocating movement speed of piston 140 is reduced during low speed operation. Furthermore, since an amount of oU 106 scattered in housing 101 is reduced, leakage of refrigerant from space between outer circumferential surface 150 of the piston and cyhnder 131 is likely to be increased.
• the hermetic compressor of this exemplary embodiment since oil 106 can be accumulated in under cut 153 and inchnation in the vertical direction of piston 140 can be suppressed, high efficiency can be maintained also during the low speed operation.
• the density of refrigerant R600a used in the hermetic compressor of this exemplary embodiment is smaUer than the density of refrigerant R134a (1,1,1,2-tetrafluoroethane), which has been conventionaUy used in refrigerators. Therefore, when refrigerating abUity that is the same as in a hermetic compressor using refrigerant R134a is intended to be obtained by using refrigerant R600a, cylinder capacity is increased and the outer diameter of piston 140 may be increased.
• crankshaft 110 may be provided with secondary axis which is provided on the same axis as main shaft 111 and opposed to main shaft with eccentric shaft 112 therebetween, and at the same time, a secondary bearing for supporting the secondary axis may be provided.
• crankshaft 110 is supported at both ends with eccentric shaft 112 sandwiched therebetween, resulting in effectively suppressing the inchnation of piston 140 in the vertical direction with respect to cylinder 131. Consequently, since the behavior of piston 140 becomes stable, shding loss can be reduced and the increase in noise can be suppressed, it is possible to reahze a hermetic compressor with high efficiency and low noise property.
• a hermetic compressor according to the present invention yields high productivity, and can increase efficiency and rehabihty, it can be widely apphed to an application of a hermetic compressor of, for example, an air conditioner, a vending machine, and the like.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Compressor (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=34968133

Family Applications (1)

Country Status (7)

Cited By (4)

Families Citing this family (15)

Citations (4)

Family Cites Families (12)

• 2004
  • 2004-05-28 JP JP2004159165A patent/JP4337635B2/ja not_active Expired - Fee Related
• 2005
  • 2005-05-11 US US10/553,847 patent/US20060257274A1/en not_active Abandoned
  • 2005-05-11 EP EP05741280A patent/EP1629198B1/en not_active Expired - Fee Related
  • 2005-05-11 WO PCT/JP2005/009006 patent/WO2005116450A1/en active IP Right Grant
  • 2005-05-11 DE DE602005002205T patent/DE602005002205T2/de not_active Expired - Fee Related
  • 2005-05-11 KR KR1020057020671A patent/KR100701527B1/ko not_active IP Right Cessation
  • 2005-05-11 CN CNB2005800001747A patent/CN100430598C/zh not_active Expired - Fee Related

Patent Citations (4)

Non-Patent Citations (1)

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