JP5347721B2 - Hermetic compressor - Google Patents

Abstract

The present invention provides a seal compressor. In the seal compressor, a seal container is stored with lubricant oil and provided with an electric member and a compression member, wherein the compression member includes a rotating shaft having a principal shaft part fixed with a rotor, an eccentric shaft part and a flange part; an air cylinder block; a piston; a connection part for connecting the piston and the eccentric shaft part; a main bearing for supporting the principal shaft part; and a thrust ball bearing attached between a thrust surface of the main bearing and the flange part; onthe flange part, a counterweight body is arranged in a symmetrical direction of the eccentric shaft part using a central line of the principal shaft part as the symmetry axis at a position below a lower end face contacting with the thrust ball bearing in the vertical direction and in the projection of the principal shaft part in the axial center direction.

Description

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

  Conventionally, as a hermetic compressor using a thrust ball bearing, there is one in which a rolling bearing is disposed around an upper bearing extension of a main bearing (see, for example, Patent Document 1).

  Hereinafter, the conventional hermetic compressor will be described with reference to the drawings.

  7 is a longitudinal sectional view of a conventional hermetic compressor described in Patent Document 1, FIG. 8 is an enlarged view of a main part of a thrust ball bearing of the conventional hermetic compressor, and FIG. 9 is a conventional hermetic compressor. It is a schematic diagram which shows the action force of a machine. 10 is a longitudinal sectional view of another conventional hermetic compressor, FIG. 11 is (A) a schematic diagram showing the acting force of the hermetic compressor at the bottom dead center in FIG. 10, and (B) in FIG. It is a schematic diagram which shows the action force of the hermetic compressor at the top dead center.

  In FIG. 7, 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, a flange portion 21 provided at the upper end of the main shaft portion 20, and an eccentric shaft portion 22 extending from the upper surface of the flange portion 21, and the main shaft portion 20 is a cylinder block. The rotor 16 is fixed to the 24 main bearings 26 while being rotatably supported. And it is the structure of the cantilever bearing supported with the main axis | 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 load acts.

  Further, the shaft 18 includes an oil supply mechanism 28 including a spiral groove provided on the surface of the main shaft portion 20.

  The piston 30 is reciprocally inserted into a cylinder 34 having a substantially cylindrical inner surface formed in the cylinder block 24. Further, the connecting means 36 connects the eccentric shaft portion 22 and the piston 30 by fitting the holes provided at both ends into a piston pin (not shown) attached to the piston 30 and the eccentric shaft portion 22, respectively. doing.

  The cylinder 34 and the piston 30 form a compression chamber 42 together with the valve plate 40 attached to the open end surface of the cylinder 34. Further, a cylinder head 44 is fixed so as to cover the valve plate 40 and cover it.

  The suction muffler 46 is molded from a resin such as PBT, forms a silencing space inside, and is attached to the cylinder head 44.

  Next, the thrust ball bearing 66 will be described with reference to FIG.

  The main bearing 26 has a thrust surface 50 which is a flat portion perpendicular to the axis on the upper end surface.

  A thrust ball bearing 66 including an upper race 54, a ball 56 held by a holder portion 58, and a lower race 60 is disposed above the thrust surface 50.

  The upper race 54 and the lower race 60 are annular and metal flat plates, and the upper and lower surfaces are parallel. Further, the holder portion 58 has an annular shape, and accommodates the balls 56 in a plurality of holes provided in the circumferential direction so as to roll freely.

  The lower race 60, the ball 56, and the upper race 54 are stacked on the thrust surface 50 in the order of contact with each other, and the flange portion 21 of the shaft 18 is seated on the upper surface of the upper race 54.

  Next, the balance weight 74 will be described with reference to FIG.

  The flange portion 21 of the shaft 18 has an extension portion 21 a opposite to the eccentric shaft portion 22, and the center of gravity of the horizontal cross section of the flange portion 21 is the center of the eccentric shaft portion 22 with respect to the axis of the main shaft portion 20. Located in the opposite direction.

  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 through the connecting means 36, and the piston 30 reciprocates in the cylinder 34.

  The refrigerant returned from the refrigeration cycle (not shown) outside the sealed container 2 is introduced into the compression chamber 42 via the suction muffler 46 and is compressed by the piston 30 in the compression chamber 42, and the compressed refrigerant is sealed. It is sent from the container 2 to the refrigeration cycle.

  The lower end of the shaft 18 is immersed in the lubricating oil 4, and when the shaft 18 rotates, the lubricating oil 4 is supplied to each part of the compression element 12 by the oil supply mechanism 28 and lubricates the sliding portion.

  The thrust ball bearing 66 is a rolling bearing in which the ball 56 rolls in a point contact state with the upper race 54 and the lower race 60, and can rotate while supporting a vertical load such as the weight of the shaft 18 and the rotor 16. is there. Rolling bearings have less friction than commonly used sliding bearing type thrust bearings, and in recent years, they are increasingly used for the purpose of higher efficiency.

  Next, the operation of the balance weight 74 will be described with reference to FIG.

  FIG. 9 shows the acting force when the piston 30 is positioned near the bottom dead center.

  When the compressor body 6 is operated, the eccentric shaft portion 22 rotates eccentrically, and thus the centrifugal force 80 acts on the eccentric shaft portion 22. Further, the piston 30 connected to the eccentric shaft portion 22 via the connecting means 36 reciprocates in the cylinder 34 to generate an inertial force 82.

  For the purpose of reducing the vibration of the compressor main body 6 due to these acting forces, a balance weight 74 composed of the extending portion 21a of the flange portion 21 is configured, and the centrifugal force acting on the eccentric shaft portion 22 is applied to the flange portion 21. The centrifugal force 84 opposite to the inertia force 82 of the piston 80 and the piston 30 acts. Therefore, when these acting forces cancel each other, the force acting on the compressor body 6 can be reduced, and vibration can be reduced.

  When the diameter and amplitude of the piston 30 are increased while reducing the size, such as when isobutane having the same capacity and a large cylinder volume is used as the refrigerant, the size of the flange portion 21 is reduced in order to prevent interference with the piston 30. Furthermore, since the mass of the piston 30 itself increases, it is necessary to increase the mass of the balance weight 74 in order to reduce vibration. In this case, as shown in FIG. 10, a balance weight 74 is attached to the upper end of the shaft 18 to reduce vibration.

  The acting force in the conventional example shown in FIG. 10 will be described with reference to FIG.

  FIG. 11A shows the acting force near the bottom dead center. As in FIG. 9, the flange portion 21 and the balance weight 74 are arranged so as to balance the centrifugal force 80 acting on the eccentric shaft portion 22 and the inertial force 82 acting on the piston 30, and the centrifugal force 86 and the centrifugal force 84 respectively. Act.

  However, since the flange portion 21 has a small outer shape to prevent interference with the piston 30, only a small centrifugal force 86 can be obtained. Therefore, a larger centrifugal force 84 acts on the balance weight 74 and the turning radius becomes large. The centrifugal force 80 acting on the eccentric shaft portion 22 and the inertial force 82 of the piston 30 which has increased in diameter and amplitude are balanced.

  Further, (B) shows the acting force near the top dead center. In the vicinity of the top dead center, the compressive load 88 acts in the same direction as the centrifugal force 84 acting on the balance weight 74.

JP 2005-127305 A

  However, in the above-described conventional configuration, the centrifugal force 84 acting on the balance weight 74 is larger than the centrifugal force 86 acting on the flange portion 21 and is further away from the main bearing 26, so that the balance weight 74 acts. The moment is increased, the load acting on the main bearing 26 is increased, and by acting simultaneously with the compressive load 88, the bearing load is further increased, the sliding loss of the main bearing 26 is increased, and the reliability is increased. It had the problem of reducing.

  An object of the present invention is to solve the conventional problems described above, and to prevent an increase in bearing load due to centrifugal force acting on a weight, and to realize a highly efficient and reliable hermetic compressor.

  In order to solve the above-described conventional problems, the hermetic compressor of the present invention is in a position vertically below the lower end surface in contact with the thrust ball bearing on the flange portion, and in the projection in the axial direction of the main shaft portion. A weight is provided at a position symmetrical to the eccentric shaft portion, and has an effect of preventing an increase in bearing load due to a moment due to a centrifugal force acting on the weight while reducing vibration with the weight.

  Since the hermetic compressor of the present invention prevents an increase in bearing load due to the weight, efficiency and reliability can be improved by reducing frictional wear.

1 is a longitudinal sectional view of a hermetic compressor according to Embodiment 1 of the present invention. The main part enlarged view of the thrust ball bearing in the same embodiment External view of shaft in the same embodiment Schematic diagram showing the positional relationship between the shaft and weight and the piston in the same embodiment (A) Schematic diagram showing the working force of the hermetic compressor at the bottom dead center in the same embodiment (B) Schematic diagram showing the working force of the hermetic compressor at the top dead center in the same embodiment Vertical sectional view of another hermetic compressor in the same embodiment Vertical section of a conventional hermetic compressor Enlarged view of the main parts of a thrust ball bearing of a conventional hermetic compressor Schematic diagram showing the working force of a conventional hermetic compressor Vertical sectional view of another conventional hermetic compressor (A) Schematic diagram showing the working force of the hermetic compressor at the bottom dead center in FIG. 10 (B) Schematic diagram showing the working force of the hermetic compressor at the top dead center in FIG.

The invention according to claim 1 stores lubricating oil in an airtight container, accommodates an electric element including a stator and a rotor, and a compression element disposed above the electric element, and The element includes a shaft having a main shaft portion, an eccentric shaft portion, and a flange portion to which the rotor is fixed, a cylinder block having a compression chamber, and a piston inserted in the compression chamber so as to be able to reciprocate. A connecting means for connecting the piston and the eccentric shaft portion, a main bearing for supporting the main shaft portion of the shaft, and a thrust ball disposed between a thrust surface of the main bearing and the flange portion and a bearing, the flange portion, at a position vertically below the lower end surface abutting on the thrust ball bearing, and in the axial direction of the projection of the main spindle section, meet the eccentric shaft portion and symmetrical position The And, those having a weight which is arranged close to the outer diameter side of the thrust ball bearing, because the bearing load is not increased by the centrifugal force acting on the weights, to achieve efficiency and the reliability be able to.
According to a second aspect of the present invention, the lubricating oil splashed in the outer diameter direction from the thrust ball bearing by centrifugal force rebounds on the weight and lubricates the thrust ball bearing.

According to a third aspect of the present invention, in the second aspect of the invention, a balance weight is provided on the side opposite to the main shaft portion of the eccentric shaft portion, and the centrifugal force of the eccentric shaft portion and the inertial force of the piston are The balance between the weight and the balance weight arranged on both sides makes it possible to minimize the unbalance of the compression portion. In addition to the effect of the invention according to claim 1, the vibration is further reduced and the bearing is reduced. The load can be reduced and the efficiency and reliability can be improved.

The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the upper end surface of the weight is located vertically below the lower end portion of the piston, and the main shaft portion. In the projection in the axial direction, the outer peripheral portion of the flange portion is formed in a shape in which the shortest distance from the end surface of the piston is substantially constant regardless of the rotation of the main shaft portion, and interference with the piston In addition to the effect of the invention according to any one of claims 1 to 3, it is possible to improve efficiency and reliability while maintaining a small shape. it can.
According to a fifth aspect of the present invention, in the invention of the fourth aspect, the shape of the flange portion is such that the radius from the center of the main shaft portion is small in the direction opposite to the eccentric shaft portion and the radius in the lateral direction. It has a large shape.
The invention according to claim 6 is the invention according to claim 5, wherein the weight is obtained by fixing both ends of the weight to the flange.

The invention according to claim 7 is the bearing extension portion according to any one of claims 1 to 6 , wherein the main bearing overlaps with a weight in the axial direction in a cross section in the axial direction of the main shaft portion. In addition to the effects of the invention according to any one of claims 1 to 4, the bearing load is further reduced, and the efficiency and reliability are further reduced. Can be improved.

  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)
FIG. 1 is a longitudinal sectional view of a hermetic compressor according to Embodiment 1 of the present invention. FIG. 2 is an enlarged view of a main part of the thrust ball bearing in the embodiment, and FIG. 3 is an external view of the shaft in the embodiment. FIG. 4 is a schematic diagram showing the positional relationship between the shaft and weight and the piston in the embodiment, and FIG. 5A is a schematic diagram showing the acting force of the hermetic compressor at the bottom dead center in the embodiment. (B) It is a schematic diagram which shows the action force of the hermetic compressor in the top dead center in the same embodiment, FIG. 6 is a longitudinal cross-sectional view of another hermetic compressor in the same embodiment.

  In FIGS. 1 and 2, lubricating oil 104 is stored at the inner bottom of the sealed container 102, and the compressor main body 106 is suspended inside the sealed container 102 by a suspension spring 108. The sealed container 102 is filled with R600a (isobutane), which is a refrigerant with a low global warming potential.

  The compressor body 106 includes an electric element 110 and a compression element 112 driven by the electric element 110, and a power supply terminal 113 for supplying power to the electric element 110 is attached to the sealed container 102.

  First, the electric element 110 will be described.

  The electric element 110 includes a stator 114 formed by winding a copper winding around an iron core in which thin plates are laminated, and a rotor 116 disposed on the inner diameter side of the stator 114. Is connected to a power source (not shown) outside the hermetic compressor through a power terminal 113 by a conductive wire.

  Next, the compression element 112 will be described.

  The compression element 112 is disposed above the electric element 110.

  The shaft 118 constituting the compression element 112 includes a main shaft portion 120, a flange portion 121 at the upper end of the main shaft portion 120, and an eccentric shaft portion 122 extending from the upper surface of the flange portion 121 and parallel to the main shaft portion 120. A rotor 116 is fixed to the main shaft portion 120.

  The cylinder block 124 includes a main bearing 126 having a cylindrical inner surface, and the main shaft portion 120 is inserted into and supported by the main bearing 126 in a rotatable state. The compression element 112 has a configuration of a cantilever bearing that supports the load acting on the eccentric shaft portion 122 by the main shaft portion 120 and the main bearing 126 arranged below the eccentric shaft portion 122.

  Further, the shaft 118 includes an oil supply mechanism 128 including a spiral groove provided on the surface of the main shaft portion 120.

  The cylinder block 124 includes a cylinder 134 that is a cylindrical hole, and a piston 130 is reciprocally inserted into the cylinder 134.

  Further, the connecting means 136 is connected to the eccentric shaft 122 and the piston 130 by fitting the holes provided at both ends into the piston pin 138 and the eccentric shaft 122 attached to the piston 130, respectively.

  A valve plate 140 is attached to the end surface of the cylinder 134 and forms a compression chamber 142 together with the cylinder 134 and the piston 130. Further, a cylinder head 144 is fixed so as to cover the valve plate 140 and cover it. The suction muffler 146 is molded from a resin such as PBT, forms a silencing space inside, and is attached to the cylinder head 144.

  Next, the configuration of the thrust ball bearing 166 will be described.

  The main bearing 126 has a thrust surface 150 that is a flat portion perpendicular to the shaft center, and a bearing extension 152 that extends further upward than the thrust surface 150 and has an inner surface facing the main shaft portion 120.

  An upper race 154 is disposed on the upper side of the bearing extension 152, and a ball 156, a lower race 160, and a support member that are held by the holder portion 158 on the outer diameter side of the bearing extension 152 and on the lower side of the upper race 154. 162 is arranged to constitute a thrust ball bearing 166.

  The upper race 154 and the lower race 160 are annular and metal flat plates, which are preferably formed of heat-treated spring steel or the like, whose upper and lower surfaces are parallel, and whose surfaces are finished smoothly.

  The holder portion 158 is formed of a resin material such as polyamide, has an annular shape, and has a plurality of hole portions in which the balls 156 are slidably accommodated.

  On the thrust surface 150, the support member 162, the lower race 160, the ball 156, and the upper race 154 are stacked in contact with each other in this order, and the flange portion 121 of the shaft 118 is seated on the upper surface of the upper race 154.

  Next, details of the weight 172 will be described with reference to FIGS. 3 and 4.

  A weight 172 is disposed in a direction symmetrical to the eccentric shaft portion 122 with respect to the center line of the main shaft portion 120 on the lower surface of the flange portion 121. A plurality of crescent-shaped thin plates are stacked on the weight 172, and both ends are fixed to the flange portion 121 with screws 176.

  The weight 172 is disposed on the outer diameter side of the bearing extension 152 of the main bearing 126 and the thrust ball bearing 166.

  FIG. 4 shows the positional relationship between the shaft 118 and the weight 172 and the piston 130 at each crank angle. The connecting means 136 is omitted for easy understanding of the positional relationship, but the distance between the eccentric shaft portion 122 and the piston pin 138 is constant.

In the projection in the axial direction of the main shaft portion 120, the outer peripheral portion of the flange portion 121 is formed in a shape in which the shortest distance from the end face of the piston 130 is substantially constant regardless of the rotation of the main shaft portion 120. Specifically, as shown in FIG. 4, the shape of the flange portion 121 is such that the radius from the center of the main shaft portion 120 is small in the direction opposite to the eccentric shaft portion 122 and large in the lateral direction.

  Therefore, as the crank angle advances from 90 degrees to 135 degrees and 180 degrees (bottom dead center), the piston 130 jumps out to the rear of the cylinder 134. In each of these states, the piston 130 and the flange portion 121 It has a predetermined gap. Further, the weight 172 is positioned below the piston 130 in the vicinity of the bottom dead center, as shown in a state where the crank angle is 135 degrees or 180 degrees.

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

  When the electric element 110 is energized from the power supply terminal 113, the rotor 116 rotates together with the shaft 118 by the magnetic field generated in the stator 114. The eccentric rotation of the eccentric shaft portion 122 accompanying the rotation of the main shaft portion 120 is converted by the connecting means 136 and causes the piston 130 to reciprocate within the cylinder 134. Then, when the volume of the compression chamber 142 changes, a compression operation is performed in which the refrigerant in the sealed container 102 is sucked into the compression chamber 142 and compressed.

  In the suction stroke accompanying this compression operation, the refrigerant in the sealed container 102 is intermittently sucked into the compression chamber 142 via the suction muffler 146 and compressed in the compression chamber 142, and then the high-temperature and high-pressure refrigerant is discharged. It is sent to a refrigeration cycle (not shown) from the sealed container 102 via a pipe or the like.

  Further, the lower end of the shaft 118 is immersed in the lubricating oil 104, and when the shaft 118 rotates, the lubricating oil 104 supplies the main shaft portion 120 and the main bearing 126 by the oil supply mechanism 128 and then reaches the flange portion 121. Here, most of the lubricating oil 104 is supplied to each sliding part such as the piston 130 via the eccentric shaft part 122, but a part is supplied to the thrust ball bearing 166 from the flange part 121.

  The thrust ball bearing 166 has a very small friction by arranging a plurality of balls 156 of the same size between the flat upper race 154 and the lower race 160 so that each rolls in a point contact state. Therefore, the efficiency of the hermetic compressor can be improved by reducing the sliding loss.

  As shown in FIG. 4, the weight 172 is disposed so as to be located below the piston 130 at the bottom dead center, for example, the distance between the piston 130 and the main bearing 126 is separated in the horizontal direction or the vertical direction. Since the balance weight 174 having an appropriate mass can be disposed, vibration can be reduced without increasing the size of the hermetic compressor.

  In addition, the shape of the flange portion 121 is such that the maximum centrifugal force is obtained in a limited space while avoiding interference with the piston 130, and the centrifugal portion acting on the eccentric shaft portion 122 or the like. It is possible to balance the force 180 (see FIG. 5) at a position where the distance in the vertical direction is small. Further, the flange portion 121 has a large radius in the direction orthogonal to the eccentric shaft portion 122. By fixing the weight 172 at this position, the weight 172 having a large rotation radius can be fixed in a limited space.

  Further, by arranging the weight 172 in a space vacated on the outer diameter side of the thrust ball bearing 166, the space in the hermetic compressor can be used effectively.

Further, the lubricating oil 104 is supplied to the thrust ball bearing 166 by an oil supply mechanism 128 provided on the shaft 118. However, since the thrust ball bearing 166 is rotating, the lubricating oil 104 supplied by centrifugal force is in the outer diameter direction. Scatter. However, since the weight 172 is disposed close to the outer diameter side of the thrust ball bearing 166, the scattered lubricating oil 104 rebounds on the weight 172 and lubricates the thrust ball bearing 166 again. Reliability is improved.

  Next, the force acting on the weight 172 and the like will be described with reference to FIG.

  When the compressor main body 106 operates, the eccentric shaft portion 122 rotates eccentrically, so that the centrifugal force 180 acts on the eccentric shaft portion 122. Further, the piston 130 connected to the eccentric shaft portion 122 via the connecting means 136 reciprocates in the cylinder 134, whereby an inertial force 182 is generated.

  For the purpose of reducing the vibration of the compressor main body 106 due to these acting forces, a flange portion 121 and a weight 172 are disposed below the piston 130, and a balance weight 174 is disposed above the piston 130.

  A centrifugal force 184 acts on the balance weight 174, and a centrifugal force 186 acts on the weight 172. Centrifugal force is the product of the rotational radius of the center of gravity of each weight, the mass and the square of the rotational angular velocity, and the weight 172 has a larger rotational radius and larger mass than the balance weight 174. Greater than 184.

  Further, the balance weight 174 and the weight 172 are sized so that the sum of the centrifugal force 184 and the centrifugal force 186 acting on the balance weight 174 and the centrifugal force 180 acting on the eccentric shaft portion 122 and the inertial force 182 of the piston 130 are substantially balanced. Have been selected to be. As a result, when these acting forces cancel each other, the force acting on the compressor body 106 can be reduced, and vibration can be reduced.

  In addition, since the weight 172 and the balance weight 174 are arranged above and below the piston 130, the moment due to the difference in position at which each acting force acts on the compressor body 106 can be reduced, thereby further reducing vibration. Can do.

  Further, when considering the load acting on the bearing, as already described in the vicinity of the bottom dead center shown in FIG. Further, in the vicinity of the top dead center shown in (B), the compression load 188 is added to the state of (A), so that the bearing load increases. However, the load by the weight 172 does not increase further as in the conventional case. The loss of the bearing can be reduced or the reliability can be improved.

  In the cross section of the main shaft 120 in the axial direction, the main bearing 126 includes a bearing extension 152 that overlaps the weight 172 in the axial direction, and the moment caused by the centrifugal force 186 acting on the weight 172 being separated from the main bearing 126. Therefore, bearing load can be reduced, and efficiency and reliability can be improved.

  In this embodiment, the balance weight 174 is provided at the upper end of the eccentric shaft portion 122. However, as shown in FIG. 6, only the balance weight 174 below the piston 130 may be provided without providing the weight 172 at the upper end of the shaft 118. . In this case, compared to the case where the weights 172 are provided on both the upper and lower sides, the moment due to the subtraction of the acting force is slightly increased, but the hermetic compressor can be reduced in weight and the number of parts can be reduced.

  In addition, since the direction of the moment is opposite to the direction in which the compressive load acts, the bearing load at the time of high load can be reduced, which is advantageous in terms of reliability at the time of high load.

  As described above, since the hermetic compressor according to the present invention can improve performance and reliability by using a thrust ball bearing, it is not limited to an electric refrigerator-freezer for home use but also an air conditioner, a vending machine and other refrigeration units. Widely applicable to devices etc.

DESCRIPTION OF SYMBOLS 102 Airtight container 104 Lubricating oil 110 Electric element 112 Compression element 114 Stator 116 Rotor 118 Shaft 120 Main shaft part 121 Flange part 122 Eccentric shaft part 124 Cylinder block 126 Main bearing 130 Piston 136 Connecting means 142 Compression chamber 150 Thrust surface 152 Bearing extension Part 166 Thrust ball bearing 172 Weight 174 Balance weight

Claims (7)

An electric element having a stator and a rotor, and storing lubricating oil in a sealed container;
A compression element disposed above the electric element, and the compression element includes a shaft having a main shaft portion, an eccentric shaft portion, and a flange portion to which the rotor is fixed;
A cylinder block with a compression chamber;
A piston inserted in the compression chamber so as to be capable of reciprocating;
Connecting means for connecting the piston and the eccentric shaft portion;
A main bearing that pivotally supports the main shaft portion of the shaft;
A thrust ball bearing disposed between the thrust surface of the main bearing and the flange portion;
The flange portion has a position vertically below a lower end surface in contact with the thrust ball bearing, and a position symmetrical to the eccentric shaft portion in the projection in the axial direction of the main shaft portion , and the A hermetic compressor having a weight disposed close to the outer diameter side of a thrust ball bearing . 2. The hermetic compressor according to claim 1, wherein the lubricating oil splashed in an outer diameter direction from the thrust ball bearing by centrifugal force rebounds on the weight and lubricates the thrust ball bearing. The hermetic compressor according to claim 1 or 2 with a balance weight in the counter-spindle portion side of the eccentric shaft portion. The upper end surface of the weight is positioned vertically below the lower end portion of the piston, and in the projection in the axial direction of the main shaft portion, the outer peripheral portion of the flange portion has the shortest distance from the end surface of the piston. The hermetic compressor according to any one of claims 1 to 3, wherein the hermetic compressor is formed in a shape that is substantially constant regardless of rotation of the main shaft portion. 5. The hermetic compressor according to claim 4, wherein the flange portion has a shape in which a radius from a center of the main shaft portion is small in a direction opposite to the eccentric shaft portion and large in a lateral direction. The hermetic compressor according to claim 5, wherein the weight has both ends of the weight fixed to the flange. The hermetic compressor according to any one of claims 1 to 6 , wherein the main bearing includes a bearing extension that overlaps the weight in the axial direction in a cross section in the axial direction of the main shaft.