JP2013234575A - Hermetic type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hermetic type compressor with low noise, high efficiency and high reliability, while compatibly achieving both the consistent supply of lubricating oil to a thrust ball bearing and the smooth rolling of balls.SOLUTION: A hermetic type compressor has a thrust ball bearing 132 consisting of a plurality of balls 134 held by a holder part 133, an upper race 135 and a lower race 136. The ball 134 side of the upper race 135 is formed with a flat surface, and a bearing ring 160 formed with an annular groove is included on the ball 134 side of the lower race 136. Thus, lubricating oil 102 is stored in the bearing ring 160 of the lower race 136 to allow the consistent supply of the lubricating oil to the balls 134, the upper race 135 and the lower race 136. Further, since the bearing ring 160 is formed only in the lower race 136, the balls 134 are guided only by the bearing ring 160 of the lower race 136, and rolled smoothly, and low noise, high efficiency and high reliability can be achieved.

Description

  The present invention relates to a hermetic compressor used in a refrigeration cycle such as a refrigerator-freezer.

  In recent years, with regard to hermetic compressors used in refrigeration apparatuses such as refrigerators and refrigerators, high efficiency, low noise, and high reliability for reducing power consumption are desired.

  Conventionally, this type of hermetic compressor employs a thrust ball bearing to improve efficiency (for example, see Patent Document 1).

  Furthermore, there is a structure in which upper and lower races constituting a thrust ball bearing are provided with race rings formed by annular depressions (for example, see Patent Document 2).

Hereinafter, the conventional hermetic compressor will be described with reference to the drawings.
4 is a longitudinal sectional view of a conventional hermetic compressor described in Patent Document 1, and FIG. 5 is an enlarged view of a main part of a thrust ball bearing of the conventional hermetic compressor described in Patent Document 1. 6 is an exploded perspective view of a thrust ball bearing of a conventional hermetic compressor described in Patent Document 1. FIG.

  4, 5, and 6, the lubricating oil 4 is stored at the bottom of the sealed container 2, and the compressor body 6 is elastically supported by the suspension container 8 with respect to the sealed container 2.

  The compressor body 6 includes an electric element 10 and a compression element 12 disposed above the electric element 10. The electric element 10 includes a stator 14 and a rotor 16. The shaft 18 of the compression element 12 includes a main shaft portion 20 and an eccentric shaft portion 22. The main shaft portion 20 is rotatably supported by a main bearing 26 of the block 24, and the rotor 16 is fixed. And it is the structure of the cantilever bearing supported with the main shaft part 20 and the main bearing 26 which are arrange | positioned only to the lower side of the eccentric shaft part 22 with respect to the eccentric shaft part 22 to which a compressive load acts.

  The shaft 18 includes an oil supply mechanism 28 formed of a spiral groove or the like provided on the surface of the main shaft portion 20, and includes an oil supply path 29 that communicates with the upper end of the oil supply mechanism 28 and extends above the eccentric shaft portion 22. ing.

  The piston 30 is reciprocally inserted into a cylinder 34 having a substantially cylindrical inner surface formed in the block 24. In addition, the coupling portion 36 has holes (not shown) provided at both ends fitted into the piston pin 38 and the eccentric shaft portion 22 attached to the piston 30, respectively, so that the eccentric shaft portion 22 and the piston 30 are connected. It is connected.

  The cylinder 34 and the piston 30 form a compression chamber 48 together with the valve plate 46 attached to the opening end surface of the cylinder 34. Further, the cylinder head 50 is fixed so as to cover the valve plate 46 and cover it.

  The suction muffler 52 is molded from a resin such as PBT, forms a silencing space inside, and is attached to the cylinder head 50.

  Next, the thrust ball bearing 76 will be described.

  The main bearing 26 includes a thrust surface 60 that is a flat portion perpendicular to the shaft center, and a bearing extending portion 62 that extends further upward than the thrust surface 60 and has an inner surface facing the main shaft portion 20. A thrust ball bearing 76 including an upper race 64, a ball 66 held by a holder portion 68, and a lower race 70 is disposed on the outer diameter side of the bearing extension portion 62. The lower race 70 is supported by a support member 72.

  The upper race 64 and the lower race 70 are annular and metal flat plates, and the upper and lower surfaces are parallel. The holder portion 68 has an annular shape, and accommodates the balls 66 in a plurality of holes provided in the circumferential direction so as to be freely rollable.

  On the thrust surface 60, the support member 72, the lower race 70, the ball 66, and the upper race 64 are stacked in contact with each other in this order, and the flange portion 74 of the shaft 18 is seated on the upper surface of the upper race 64. A predetermined axial clearance 78 is provided between the upper end of 62 and the flange portion 74 of the shaft 18.

  The operation of the hermetic compressor configured as described above will be described below.

  When the electric element 10 is energized, the rotor 16 rotates together with the main shaft portion 20 by the rotating magnetic field generated in the stator 14. Due to the rotation of the main shaft portion 20, the eccentric shaft portion 22 moves eccentrically, and the eccentric movement of the eccentric shaft portion 22 is transmitted to the piston 30 via the connecting portion 36, and the piston 30 reciprocates in the cylinder 34.

  The refrigerant returned from the refrigeration cycle (not shown) outside the hermetic container 2 is introduced into the compression chamber 48 via the suction muffler 52, and is compressed by the piston 30 in the compression chamber 48, and the compressed refrigerant is sealed. It is sent out from the container 2 to the refrigeration cycle.

  Further, the lower end of the shaft 18 is immersed in the lubricating oil 4, and when the shaft 18 rotates, the lubricating oil 4 lubricates the main shaft portion 20 by the oil supply mechanism 28, and then the thrust ball bearing 76 from the axial gap 78. And supply to each part of the compression element 12 through the oil supply path 29 to lubricate the sliding part.

Japanese Patent No. 4268519

  However, in the configuration in which the conventional upper race 64 and lower race 70 are flat plates, when the lubricating oil 4 is supplied to the thrust ball bearing 76, the lubricating oil 4 flows out to the outer peripheral side of the upper race 64 or the lower race 70. The amount of the lubricating oil 4 that is directly supplied to the surface of the ball 66 may be insufficient depending on the operating conditions, which may increase noise and reduce efficiency.

  In addition, for example, a configuration in which a raceway formed by an annular groove is provided in the upper race or the lower race is conceivable. In this case, lubricating oil accumulates in the raceway of the lower race and is supplied to the surface of the ball. Lubricating oil is stable. However, depending on the accuracy of the parts of the upper race and the lower race and the operating conditions, the shaft center of the upper race raceway and the axis of the lower race raceway may be misaligned. There is a possibility that the contact state of the ball becomes unstable and the smooth rolling of the ball is hindered.

  The present invention solves the above-mentioned conventional problems, and provides a low-noise, high-efficiency hermetic compressor that achieves both stable supply of lubricating oil to the ball and race and smooth rolling of the ball. For the purpose.

  In order to solve the above-described conventional problems, the hermetic compressor according to the present invention includes a raceway formed by a flat surface on the ball side of the upper race and an annular groove on the ball side of the lower race.

  As a result, the lubricating oil supplied in the vicinity of the thrust ball bearing accumulates in the race wheel of the lower race, and the contact portion between the starting wheel of the lower race and the ball is stably filled with the lubricating oil. In addition, since the ball rolls on the race ring of the lower race where the lubricant is accumulated, the lubricant is stably supplied to the surface of the ball, so the lubricant is also stably supplied to the contact portion between the upper race and the ball. Is done.

  Further, since the upper race is flat, the load restrained in the horizontal direction from the upper race is small, and the ball is guided only by the race of the lower race and rolls along the race. Therefore, as in the case where the races are formed in both the upper race and the lower race, the ball contact state becomes unstable due to the axial misalignment of the upper and lower races, and the balls roll smoothly. Is less likely to be hindered, and the ball is likely to roll stably.

  Therefore, the stable supply of the lubricating oil to the ball and the race and the smooth rolling of the ball can be achieved at the same time, and low noise, high efficiency and high reliability can be achieved.

  In the hermetic compressor of the present invention, the lubricating oil accumulates in the raceway which is the annular groove of the lower race, and the lubricant can be stably supplied to the ball and the race, and the raceway is formed only in the lower race. Therefore, the ball is guided smoothly only by the raceway of the lower race and rolls smoothly, and it is possible to increase reliability with low noise and high efficiency.

1 is a longitudinal sectional view of a hermetic compressor according to an embodiment of the present invention. The main part enlarged view of the thrust ball bearing in the same embodiment The exploded perspective view of the thrust ball bearing in the embodiment Vertical section of a conventional hermetic compressor Enlarged view of the main parts of a thrust ball bearing of a conventional hermetic compressor An exploded perspective view of a thrust ball bearing of a conventional hermetic compressor

  A first invention includes, in an airtight container, an electric element including a stator and a rotor, a compression element driven by the electric element, and a lubricating oil that lubricates the compression element. A shaft having a main shaft portion to which the rotor is fixed and an eccentric shaft portion, a block having a compression chamber, a piston that reciprocates in the compression chamber, and a connecting portion that connects the piston and the eccentric shaft portion. A main bearing that is provided on the block and supports the main shaft portion, and a thrust ball bearing that is provided on a thrust surface that supports a load in the gravity direction of the shaft and the rotor, the thrust ball bearing comprising: A plurality of balls held by the holder portion, and an upper race and a lower race respectively disposed above and below the balls, and the ball side of the upper race is formed in a plane. Since the lower race has a raceway formed by an annular groove on the ball side, the lubricating oil supplied to the vicinity of the thrust ball bearing accumulates in the raceway of the lower race, and the lubricant is applied to the surface of the ball. Since the oil is stably supplied, the lubricating oil is stably supplied to the contact portion between the ball and the upper race and the lower race.

  Further, since the upper race is flat, the load restrained in the horizontal direction from the upper race is small, and the ball is guided only by the race of the lower race and rolls along the race. Therefore, unlike the conventional case, it is difficult for the smooth rolling of the ball to be hindered by the displacement of the upper and lower race rings, and the ball is likely to roll stably.

  Therefore, the stable supply of the lubricating oil to the ball and the race and the smooth rolling of the ball can be achieved at the same time, and low noise, high efficiency and high reliability can be achieved.

  According to a second aspect of the present invention, in the first aspect of the invention, the shaft is provided with oil supply means for supplying lubricating oil from the outer peripheral portion of the shaft to the inner periphery of the thrust ball bearing, and supply of the lubricating oil to the thrust ball bearing Since the upper race is flat and the upper race is flat, the clearance between the holder and the upper race is larger than when the race is formed as an annular groove in the upper race. Cheap.

  According to a third invention, in the first or second invention, the engine is operated at a plurality of operating frequencies including a rotational speed lower than the commercial power supply frequency, and at low speed rotation where the supply of lubricating oil is apt to be insufficient, centrifugal force As a result, the effect of the first or second invention can be obtained at the time of high-speed rotation at which the lubricating oil is likely to be scattered from the upper race, so that the improvement effect is great.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the viscosity of the lubricating oil is VG3 to VG8, and the low-viscosity lubricating oil that easily causes an oil film breakage at a sliding portion of the ball bearing Since the effect of any one of the first to third inventions can be obtained, the improvement effect is great.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
1 is a longitudinal sectional view of a hermetic compressor according to a first embodiment of the present invention, FIG. 2 is an enlarged view of a main part of a thrust ball bearing in the same embodiment, and FIG. 3 is a thrust ball in the same embodiment. It is a disassembled perspective view of a bearing.

  1, 2, and 3, lubricating oil 102 is stored in an airtight container 101, and an electric element 105 including a stator 103 and a rotor 104 and a compression element 106 driven by the electric element 105 are accommodated. The The shaft 110 includes a main shaft portion 111 to which the rotor 104 is fixed, and an eccentric shaft portion 112 that is disposed above the main shaft portion 111 and is formed eccentric to the main shaft portion 111.

  The block 114 has a substantially cylindrical compression chamber 116 to which a main bearing 120 that supports the main shaft portion 111 is fixed. The piston 126 is inserted into the compression chamber 116 of the block 114 so as to be slidable back and forth, and is connected to the eccentric shaft portion 112 by a connecting portion 128.

  The main bearing 120 of the block 114 includes a thrust surface 130 formed in an annular shape substantially perpendicular to the axis of the main bearing 120, and a bearing extension having an inner surface facing the main shaft portion 111 and extending further upward than the thrust surface 130. Part 144. In order to support the shaft 110 in the vertical direction, the lower race 136, the plurality of balls 134, the holder portion 133 that holds the balls 134, and the upper race 135 are arranged in this order from the outer thrust surface 130 of the bearing extension portion 144 to the upper side. It is arranged.

  The lower race 136, the plurality of balls 134, the holder portion 133, and the upper race 135 constitute a thrust ball bearing 132.

  Further, the lower race 136 and the holder portion 133 are all arranged with a radial clearance secured outside the bearing extension portion 144.

  On the other hand, the upper race 135 is disposed further above the upper end 170 of the bearing extension 144, and the distance (height) from the thrust surface 130 to the top of the ball 134 is longer from the thrust surface 130 to the bearing extension. Since it is longer than the distance (height) to the upper end 170 of the protruding portion 144, a predetermined axial gap 146 is formed between the upper end 170 of the bearing extension portion 144 and the upper race 135 due to the dimensional difference.

  A ball 134 side of the upper race 135 is formed with a flat surface, and a race ring 160 formed with an annular groove is formed on the ball 134 side of the lower race 136. The pitch circle diameter D1 of the balls 134 disposed in the holder portion 133 and the diameter D2 of the bottom portion of the groove of the raceway 160 of the lower race 136 are formed to be substantially the same. Therefore, all the balls 134 are installed in the grooves of the raceway ring 160 and are in stable contact with the curved surface of the raceway ring 160.

  The shaft 110 is provided with a first oil supply path 150 that conveys the lubricating oil 102 from the lower part to the upper part of the main shaft part 111, and extends in the axial direction on the outer peripheral part of the main shaft part 111, and one end of the first oil supply path 150. A second oil supply path 152 communicates with the upper end and communicates with the upper end 170 of the bearing extension 144 at the other end.

  In the embodiment of the present invention, the second oil supply path 152 includes a groove 154 formed in a planar shape on the surface of the main shaft portion 111.

  Further, in the present embodiment, the refrigerant used for the hermetic compressor 100 is a hydrocarbon-based refrigerant that is a natural refrigerant with a low global warming coefficient represented by R134a and R600a whose ozone depletion coefficient is zero, Each is combined with a highly compatible lubricating oil 102.

  The operation of the hermetic compressor 100 configured as described above will be described below.

  The rotor 104 of the electric element 105 rotates the shaft 110, and the rotational movement of the eccentric shaft portion 112 is transmitted to the piston 126 via the connecting portion 128, so that the piston 126 reciprocates in the compression chamber 116. Thus, the refrigerant is sucked into the compression chamber 116 from the cooling system (not shown), compressed, and then discharged to the cooling system again.

  The weight of the shaft 110 and the rotor 104 is supported by a thrust ball bearing 132, and when the shaft 110 rotates, the ball 134 rolls between the upper race 135 and the lower race 136, so that the rotation becomes smooth.

  By using the thrust ball bearing 132, the torque for rotating the shaft 110 is smaller than that of a thrust slide bearing that does not use a ball, so that the loss in the thrust bearing can be reduced. Therefore, the input can be reduced and the efficiency can be improved.

  The lubricating oil 102 stored in the hermetic container 101 is pumped from the lower part to the upper part of the main shaft part 111 by the first oil supply path 150 provided in the shaft 110 by the centrifugal force generated by the rotation of the shaft 110.

  The lubricating oil 102 conveyed to the upper portion of the main shaft portion 111 by the first oil supply path 150 is supplied to the thrust ball bearing 132 through the planar groove 154 that is the second oil supply path 152. The second flow is distributed from the upper end of the first oil supply path 150 to the upper side of the eccentric shaft portion 112.

  The first flow flows in the radial direction through the axial gap 146 because the predetermined axial gap 146 is formed between the upper end of the bearing extension 144 and the upper race 135, and the thrust flows. The flow is toward the ball bearing 132.

  A part of the lubricating oil 102 flowing out from the axial gap 146 is directly supplied to the surface of the ball 134, and a part of the lubricating oil 102 is a gap between the ball 134 and the holder part 133, or the holder part 133 and the bearing extension part 144. Is also supplied to the upper surface of the lower race 136 through the gap. A part of the lubricating oil 102 supplied to the upper surface of the lower race 136 is accumulated in a raceway 160 formed by a groove.

  Since the lubricating oil 102 is accumulated in the raceway 160, the contact portion between the raceway 160 and the ball 134 of the lower race 136 is stably filled with the lubricant 102. Further, since the ball 134 rolls on the raceway 160 of the lower race 136 in which the lubricating oil 102 is accumulated, the lubricating oil 102 is stably supplied to the surface of the ball 134, so that the upper race 135 and the ball 134 are brought into contact with each other. Also, the lubricating oil 102 is stably supplied.

  Further, since the upper race 135 is a flat surface, the load that restrains the ball 134 from the upper race 135 in the horizontal direction is small, and the ball 134 is guided only by the raceway 160 of the lower race 136 and rolls along the raceway 160. Therefore, as in the case where the races are formed on both the upper race and the lower race, the ball contact state becomes unstable due to the displacement of the upper and lower races, and the smooth rolling of the ball is hindered. The ball 134 is easy to roll stably.

  Therefore, the stable supply of the lubricating oil 102 to the ball 134, the upper race 135, and the lower race 136 and the smooth rolling of the ball 134 can be compatible, and low noise, high efficiency, and high reliability can be achieved.

  In addition, the processing accuracy and assembly accuracy for aligning the axis of the upper race raceway and the axis of the lower race raceway as in the case where the raceway is formed in both the upper race and the lower race in the past. Is not necessary, and the manufacturing becomes easy.

  The effect obtained by the present invention is remarkable at the time of low-speed rotation in which the supply of the lubricating oil 102 is likely to be insufficient, and at the time of high-speed rotation in which the lubricating oil 102 is likely to be scattered from the upper race 135 due to centrifugal force.

  Further, in the low-viscosity lubricating oil 102 such as VG3 to VG8 in which the oil film at the contact portion between the ball 134 and the upper race 135 or the lower race 136 is easily cut, the effect obtained by the present invention is remarkable and the improvement effect is great.

  In the present embodiment, the supply of the lubricating oil 102 to the thrust ball bearing 132 has been mainly described from the second oil supply path 152 of the main shaft portion 111, but the raceway of the lower race 136 is also provided by other supply methods. If the lubricating oil 102 can be supplied to 160, the same effect can be obtained.

  As described above, since the hermetic compressor according to the present invention can reduce noise, improve efficiency, and improve reliability of thrust ball bearings, it can be applied to vending machines and air-conditioning equipment as well as refrigerators.

DESCRIPTION OF SYMBOLS 100 Sealed compressor 101 Sealed container 102 Lubricating oil 103 Stator 104 Rotor 105 Electric element 106 Compression element 110 Shaft 111 Main shaft part 112 Eccentric shaft part 114 Block 116 Compression chamber 126 Piston 128 Connection part 120 Main bearing 130 Thrust surface 132 Thrust Ball bearing 133 Holder part 134 Ball 135 Upper race 136 Lower race 152 Oil supply path 160 Track ring

Claims (4)

An airtight container includes an electric element including a stator and a rotor, a compression element driven by the electric element, and lubricating oil for lubricating the compression element, and the compression element has the rotor fixed thereto. A shaft having a main shaft portion and an eccentric shaft portion; a block having a compression chamber; a piston that reciprocates in the compression chamber; a connecting portion that connects the piston and the eccentric shaft portion; A main bearing that pivotally supports the main shaft portion, and a thrust ball bearing provided on a thrust surface that supports a load in the gravity direction of the shaft and the rotor, and the thrust ball bearing is held by a holder portion. A plurality of balls, and an upper race and a lower race respectively disposed above and below the balls, and the ball side of the upper race is formed in a plane, and the lower race Hermetic compressor having a bearing ring which is formed by an annular groove on the ball-side. The hermetic compressor according to claim 1, further comprising an oil supply path for supplying lubricating oil to the shaft from an outer peripheral portion of the shaft to an inner periphery of the thrust ball bearing. The hermetic compressor according to claim 1 or 2, wherein the hermetic compressor is operated at a plurality of operating frequencies including a rotational speed less than a commercial power frequency. The hermetic compressor according to any one of claims 1 to 3, wherein the lubricating oil has a viscosity of VG3 to VG8.