JP5120200B2 - Hermetic compressor - Google Patents

Description

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

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

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

  FIG. 8 is a longitudinal sectional view of a conventional hermetic compressor described in Patent Document 1, FIG. 9 is an enlarged view of a main part of a thrust ball bearing of the conventional hermetic compressor, and FIG. 10 is a conventional hermetic type. The perspective view of the supporting member of a compressor is shown.

  In FIG. 8, 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 cylinder block 24 and the rotor 16 is fixed. . 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 coupling means 36 couples the eccentric shaft portion 22 and the piston 30 by fitting the hole portions provided at both ends into the piston pin 38 and the eccentric shaft portion 22 attached to the piston 30, respectively.

  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 will be described.

  In FIG. 9, the main bearing 26 has a thrust surface 60 that is a flat portion perpendicular to the shaft center, and a tubular extension 62 that extends further upward than the thrust surface 60 and has an inner surface facing the main shaft portion 20. ing.

  A thrust ball bearing 76 including an upper race 64, a ball 66 held by a holder 68, a lower race 70, and a support member 72 is disposed on the outer diameter side of the tubular extension 62.

  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.

  As shown in FIG. 10, the support member 72 is formed by providing lower protrusions 72a and 72b and upper protrusions 72c and 72d on an annular metal plate. These protrusions are formed with curved surfaces having the same radius, and are arranged such that a line connecting the vertices of the lower protrusions 72a and 72b and a line connecting the vertices of the upper protrusions 72c and 72d are at right angles.

  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 on the thrust surface 60, and the flange portion 74 of the shaft 18 is seated on the upper surface of the upper race 64. The support member 72 is in contact with the thrust surface 60 with the lower projections 72a and 72b in line contact, and is in contact with the lower race 70 with the upper projections 72c and 72d in line contact.

  About the compressor comprised as mentioned above, the operation | movement is demonstrated 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 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 delivered from the container 2 to a refrigeration cycle (not shown).

  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.

  Next, the thrust ball bearing 76 will be described.

The thrust ball bearing 76 is a rolling bearing in which the ball 66 rolls in a point contact state with the upper race 64 and the lower race 70 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.
JP 2005-500476 Gazette

  However, in the above-described conventional configuration, when a large external force is applied to the entire hermetic compressor such as vibration during transportation, a large load is applied to the entire thrust ball bearing 76, and the ball 66 contacts the upper race 64 and the lower race 70. There was a problem that plastic deformation such as depression occurred in the part, and this deformation had an adverse effect on efficiency, noise, and reliability.

  The present invention solves the above-described conventional problems, and prevents high-efficiency, low-noise, and highly reliable compressors by preventing plastic deformation of the ball bearing even when a large external force such as vibration is applied during transportation. It aims at realizing.

  In order to solve the above-described conventional problems, a thrust ball bearing of a hermetic compressor according to the present invention includes a plurality of balls held by a holder portion, and an upper race and a lower race respectively disposed above and below the balls. A support member having an elastic force in the direction of gravity is arranged between the lower race or the upper race and the thrust surface. Even when a large external force is applied, the support member deforms, It has an effect of suppressing an increase in contact load between the race and the lower race and preventing plastic deformation of the thrust ball bearing.

  The hermetic compressor of the present invention prevents the contact load between the ball, the upper race, and the lower race from increasing by deforming the support member even when a large external force is applied, and prevents plastic deformation of the ball bearing. Thus, since the sliding of the thrust ball bearing can be maintained in a good state, a highly efficient, low noise, and highly reliable compressor can be realized.

  The present invention stores lubricating oil in an airtight container, and houses an electric element having a stator and a rotor, and a compression element driven by the electric element, and the compression element is fixed to the rotor. A shaft having a main shaft portion and an eccentric shaft portion, a cylinder block having a compression chamber, a piston reciprocating in the compression chamber, a connecting means for connecting the piston and the eccentric shaft portion, and the cylinder A main bearing provided on a block and supporting the main shaft portion; and a thrust ball bearing disposed on a thrust surface of the main bearing, wherein the thrust ball bearing includes a plurality of balls held by a holder portion; An upper race and a lower race are provided respectively above and below the ball, and elastic force in the direction of gravity is provided between the lower race or the upper race and the thrust surface. Even when a large external force is applied, the support member is deformed to suppress an increase in contact load between the ball and the upper race and the lower race, and plastic deformation of the thrust ball bearing is prevented. By preventing it and maintaining the sliding state of the thrust ball bearing in a good state, it is possible to improve efficiency, reduce noise, and improve reliability.

Further, the present invention enables the thrust ball bearing to be inclined with respect to the thrust surface by reducing the elastic deformation of a part of the support member when the elastic deformation of a part of the support member is increased. Even when the shaft is tilted with respect to the main bearing, the upper race and the lower race can be maintained in parallel more reliably, and damage to the thrust ball bearing due to an increased load acting on some of the balls is prevented. Therefore, high reliability can be obtained.

Further, the present invention includes a movement restricting means for restricting the movement of the shaft in the downward direction of the gravity, and the movement restricting means functions when a large load is applied to the shaft in the downward direction of the gravity. even when, to support a load in movement limiting means, the contact load of the balls and the upper race and lower race can be prevented from being extremely increased, to prevent plastic deformation of the thrust ball bearing, thrust ball By maintaining the sliding of the bearing in a good state, it is possible to improve efficiency, reduce noise, and improve reliability.

Further, the present invention, before the load exceeds the load capacity is applied to the thrust ball bearing, in which the movement limiting means to work, since the load exceeding the withstand load does not act on the thrust ball bearing, more reliably By preventing the plastic deformation of the thrust ball bearing and maintaining the sliding of the thrust ball bearing in a good state, it is possible to improve efficiency, reduce noise, and improve reliability.

Further, in the present invention, the support member is an annular wave washer, and a plurality of upper convex portions projecting toward the upper race and contacting the upper race, and a plurality of lower convex portions projecting toward the thrust surface and contacting the thrust surface The upper convex portion and the lower convex portion are alternately arranged in the circumferential direction, and the upper and lower surfaces of the wave washer and the thrust surface and the lower race are securely in contact with each other, so that the upper race and the lower race Maintaining parallelism and preventing an increase in the load acting on some of the balls, and further improving reliability, the wave washer is deformed even when a large external force is applied. The increase in contact load between the race and the lower race is suppressed, the plastic deformation of the thrust ball bearing is prevented, the reliability is improved, and the structure is simple and the size can be easily reduced.

Further, according to the present invention, the support member is formed by stacking a plurality of wave washers having the same shape, and the support member can be configured to be downsized and optimally configured according to the magnitude of the contact load. High reliability can be obtained.

Further, according to the present invention, the support member is formed by arranging a plurality of elastic bodies in the circumferential direction. By using a plurality of elastic bodies, a design that avoids local stress concentration due to deformation is facilitated and repeated. It is possible to increase the durability against deformation of the above, and by maintaining the parallelism of the upper race and the lower race by the deformation of a plurality of elastic bodies, it is possible to prevent the load acting on some balls from increasing . Further high reliability can be obtained.

Further, according to the present invention, the support member is formed of an annular tube filled with fluid and having flexibility, so that generation of noise due to rubbing or the like can be prevented and local stress concentration due to deformation of the tube can be prevented. The design that avoids the problem is easy, the durability against repeated deformation can be increased, and the deformation of the tube maintains the parallelism of the upper and lower races, increasing the load acting on some balls. Can be prevented , and higher reliability can be obtained.

  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 a thrust ball bearing of the hermetic compressor according to the embodiment, and FIG. 3 is an external view of a support member of the hermetic compressor.

  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 supply (not shown) outside the compressor via a power supply 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.

  A shaft 118 constituting the compression element 112 includes a main shaft portion 120 and an eccentric shaft portion 122 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 portion 122 and the piston 130 by fitting the holes provided at both ends into the piston pin 138 and the eccentric shaft portion 122 attached to the piston 130, respectively.

  A valve plate 146 is attached to the end surface of the cylinder 134 and forms a compression chamber 148 together with the cylinder 134 and the piston 130. Further, the cylinder head 150 is fixed so as to cover the valve plate 146 and cover it. The suction muffler 152 is molded from a resin such as PBT, forms a silencing space inside, and is attached to the cylinder head 150.

  Next, the configuration of the thrust ball bearing 176 will be described.

  The main bearing 126 includes a thrust surface 160 that is a flat portion perpendicular to the shaft center, and a tubular extension 162 that extends further upward than the thrust surface 160 and has an inner surface facing the main shaft portion 120.

  An upper race 164 is disposed on the upper side of the tubular extension 162, and a ball 166, a lower race 170, and a support member that are held by the holder portion 168 on the outer diameter side of the tubular extension 162 and on the lower side of the upper race 164. 172 is disposed to constitute a thrust ball bearing 176.

  The upper race 164 and the lower race 170 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 168 is formed of a resin material such as polyamide, has an annular shape, and has a plurality of hole portions in which the balls 166 are rotatably accommodated.

  As shown in FIG. 3, the support member 172 is an annular wave washer formed by molding a thin flat plate of spring steel, and has three upper protrusions 172a, 172b, 172c protruding upward, Three convex portions 172d, 172e, and 172f projecting to the side, the upper convex portions and the lower convex portions are alternately arranged in the circumferential direction, and the upper convex portions 172a, 172b, 172c and the downward convex portions The portions 172d, 172e, and 172f are connected by a smooth curve.

  The support member 172, the lower race 170, the ball 166, and the upper race 164 are stacked in contact with each other in this order on the thrust surface 160, and the flange portion 174 of the shaft 118 is seated on the upper surface of the upper race 164.

  Accordingly, the support member 172 is configured to be in contact with the thrust surface 160 at three locations of the lower convex portions 172d, 172e, and 172f, and to be in contact with the lower race 170 at three locations of the upper convex portions 172a, 172b, and 172c.

  When assembled in a hermetic compressor, loads such as the shaft 118 and the rotor 116 act on the support member 172 via the lower race 170 and further receive axial thrust of the electric element 110 during operation. The support member 172 has a spring property in the direction of gravity, and this load reduces the height compared to the natural length. In this state, a gap d is formed between the upper race 164 and the distal end 162a of the tubular extension 162. Each dimension and the spring constant of the support member 172 are selected so that they can.

  A movement restricting means 178 is formed by the upper race 164 and the tip 162a of the tubular extension 162 that face each other with the gap d therebetween.

  Further, the gap d is selected so that the spring force when the support member 172 is further deformed by the gap d from the initial assembly state becomes smaller than the load resistance of the thrust ball bearing 176.

  In addition, when a biased load is applied to the support member 172, the downward displacement increases on the large load side, and the displacement decreases on other portions. Therefore, the lower race 170 disposed on the support member 172 has a load. It can be tilted according to the direction of.

  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 148 changes, a compression operation is performed in which the refrigerant in the sealed container 102 is sucked into the compression chamber 148 and compressed.

  In the suction stroke accompanying this compression operation, the refrigerant in the sealed container 102 is intermittently sucked into the compression chamber 148 via the suction muffler 152 and compressed in the compression chamber 148, 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.

  The lower end of the shaft 118 is immersed in the lubricating oil 104. When the shaft 118 rotates, the lubricating oil 104 is supplied to each part of the compression element 112 by the oil supply mechanism 128 to lubricate the sliding portion.

  Next, the operation and action of the thrust ball bearing 176 will be described.

  The thrust ball bearing 176 has a very small friction by arranging a plurality of balls 166 of the same size between the flat upper race 164 and the lower race 170 so that each rolls in a point contact state. The efficiency of the compressor can be improved by reducing the sliding loss.

  The load acting on the thrust ball bearing 176 is the mass of the shaft 118 and the rotor 116 and the axial thrust of the electric element 110, and the magnitude thereof is about 10 to 20 N in a general hermetic compressor for a refrigerator. And small.

  In general, there is an appropriate value for the contact load between the ball and the race of the ball bearing. This is because if the contact load is too small, sufficient frictional force does not work between the ball and the race, and slipping occurs, resulting in damage to the surface. Conversely, if the contact load becomes too large, the stress at the contact point between the ball and the race will increase, causing problems such as fatigue failure at the contact part and plastic deformation when the load is extremely large. It is.

  Therefore, specifications such as the diameter and number of balls are selected according to the load conditions so that the contact load of the balls becomes appropriate. For this reason, when the contact load greatly deviates from the load condition assumed in the design, there arises a problem that the life is significantly reduced.

  There are two possible reasons why the contact load of the ball 166 greatly deviates from the design.

  The first is a case where the upper race 164 and the lower race 170 are not kept parallel.

  In other words, in the configuration of the cantilever bearing, the shaft 118 can be slightly tilted in the range of the gap between the main shaft portion 120 and the main bearing 126 due to a load due to compression or the like. Contact between the 164 and the lower race 170 may be uneven.

  However, the lower race 170 seated on the support member 172 can be tilted in an arbitrary direction with respect to the thrust surface 160 by the support member 172, and the upper race 164 and the lower race 170 can maintain a parallel state. The load acting on the balls 166 can be made uniform, and a reduction in life due to a large load acting on some of the balls 166 or conversely a load becoming small can be prevented.

  The second is a case where an external force is applied to the hermetic compressor.

  This is a case where an impact load is applied to the thrust ball bearing 176 due to vibration during transportation, for example. However, since the support member 172 has elasticity that deforms in the direction of gravity, the support member 172 is deformed. As a result, an increase in load at the contact portion between the ball 166 and the upper race 164 and the lower race 170 can be alleviated, and the occurrence of plastic deformation such as the contact portion being depressed can be prevented.

  Further, when the downward displacement of the shaft 118 increases and the deformation of the support member 172 increases, the load at the contact portion between the ball 166 and the upper race 164 and the lower race 170 gradually increases, but the amount of displacement is tubular with the upper race 164. When the clearance 162 becomes equal to the gap d of the tip 162a of the extension 162, the support member 172 is further deformed because it includes the movement restricting means 178 formed by the contact between the upper race 164 and the tip 162a of the tubular extension 162. The load at the contact portion between the ball 166 and the upper race 164 and the lower race 170 does not increase any more.

  Furthermore, since the spring force of the support member 172 when deformed by the gap d is made smaller than the load resistance of the thrust ball bearing 176, the thrust ball bearing 176 can be more reliably prevented from being damaged.

  As described above, by using the support member 172, even when the load is biased due to the inclination of the shaft 118 or the load on the thrust ball bearing 176 is increased by an external force, the contact between the ball 166 and the upper race 164 and the lower race 170 is achieved. It is possible to maintain the load within an appropriate range, maintain a good sliding state without wear or plastic deformation at the contact portion, and prevent deterioration in reliability. Further, since the sliding state of the thrust ball bearing 176 is well maintained, the increase in friction is small and the performance improvement effect can be maintained.

  Further, it is possible to prevent the occurrence of noise vibration due to the damage of the surface of the contact portion between the ball 166 and the upper race 164 and the lower race 170 and the instability of the contact load, and low noise can be maintained.

  In addition, although the present Example demonstrated in the example provided with the three upper convex parts 172a, 172b, 172c which protrude above, and the three lower convex parts 172d, 172e, 172f which protrude below, It can be similarly implemented by providing four or more upper convex portions and lower convex portions.

  In addition, a wave washer formed of a single flat plate is used for the support member, but depending on the size of the required load, a thrust member may be formed by using a support member formed by stacking a plurality of wave washers. In the case of being large, the parallelism of the upper race 164 and the lower race 170 can be maintained with a relatively small support member even by using a plurality of relatively strong wave washers.

  In this embodiment, the thrust ball bearing 176 is used as the bearing for the thrust surface 360. However, the same effect can be obtained by using other rolling bearings using other rollers.

  In this embodiment, the compression element 112 is disposed on the upper side of the electric element 110. However, the compression element may be provided on the lower side of the electric element. In this case, the thrust ball bearing is usually arranged between the rotor and the upper end of the main bearing.

(Embodiment 2)
FIG. 4 is a longitudinal sectional view of a hermetic compressor according to Embodiment 2 of the present invention. FIG. 5 is an enlarged view of a main part of a thrust ball bearing of the hermetic compressor according to the same embodiment.

  4 and 5, the lubricating oil 204 is stored at the inner bottom portion of the sealed container 202, and the compressor body 206 is internally suspended in the sealed container 202 by the suspension spring 208. The sealed container 202 is filled with R600a (isobutane), which is a refrigerant with a low global warming potential.

  The compressor body 206 includes an electric element 210 and a compression element 212 driven by the electric element 210, and a power supply terminal 213 for supplying power to the electric element 210 is attached to the sealed container 202.

  First, the electric element 210 will be described.

  The electric element 210 includes a stator 214 formed by winding a copper coil around an iron core in which thin plates are laminated, and a rotor 216 disposed on the inner diameter side of the stator 214. Is connected to a power supply (not shown) outside the compressor via a power supply terminal 213 by a conducting wire.

  Next, the compression element 212 will be described.

  The compression element 212 is disposed above the electric element 210.

  A shaft 218 constituting the compression element 212 includes a main shaft portion 220 and an eccentric shaft portion 222 parallel to the main shaft portion 220. A rotor 216 is fixed to the main shaft portion 220.

  The cylinder block 224 includes a main bearing 226 having a cylindrical inner surface, and the main shaft portion 220 is rotatably inserted into and supported by the main bearing 226. The compression element 212 is configured as a cantilever bearing that supports the load acting on the eccentric shaft portion 222 with the main shaft portion 220 and the main bearing 226 disposed below the eccentric shaft portion 222.

  Further, the shaft 218 includes an oil supply mechanism 228 including a spiral groove provided on the surface of the main shaft portion 220.

  The cylinder block 224 includes a cylinder 234 that is a cylindrical hole, and the piston 230 is reciprocally inserted into the cylinder 234.

  Further, the connecting means 236 is connected to the eccentric shaft portion 222 and the piston 230 by fitting the hole portions provided at both ends into the piston pin 238 and the eccentric shaft portion 222 attached to the piston 230, respectively.

  A valve plate 246 is attached to the end surface of the cylinder 234 and forms a compression chamber 248 together with the cylinder 234 and the piston 230. Further, the cylinder head 250 is fixed so as to cover the valve plate 246 and cover it. The suction muffler 252 is molded from a resin such as PBT, forms a silencing space inside, and is attached to the cylinder head 250.

  Next, the configuration of the thrust ball bearing 276 will be described.

  The main bearing 226 includes a thrust surface 260 that is a flat portion perpendicular to the shaft center, and a tubular extension 262 that extends further upward than the thrust surface 260 and has an inner surface facing the main shaft portion.

  An upper race 264 is disposed on the upper side of the tubular extension 262, and a ball 266, a lower race 270, and a support member held by the holder portion 268 are provided on the outer diameter side of the tubular extension 262 and on the lower side of the upper race 264. 272 is disposed to constitute a thrust ball bearing 276.

  The upper race 264 and the lower race 270 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 268 is formed of a resin material such as polyamide, has an annular shape, and has a plurality of hole portions in which the balls 266 are movably accommodated.

  The support member 272 is formed by arranging a plurality of elastic bodies in the circumferential direction. Specifically, four coil springs are arranged at intervals of 90 degrees.

  The support member 272, the lower race 270, the ball 266, and the upper race 264 are stacked on the thrust surface 260 in this order, and the flange portion 274 of the shaft 218 is seated on the upper surface of the upper race 264.

  When assembled in the compressor, loads such as the shaft 218 and the rotor 216 act on the support member 272 via the lower race 270, and further receive an axial thrust of the electric element 210 during operation. The support member 272 has a spring property in the direction of gravity. When the load is applied and the height is lower than the natural length, the coil springs constituting the support member 272 have the thrust surface 260 and the lower race 270, respectively. In this state, the dimensions and the spring constant of the support member 272 are selected so that a gap d is formed between the upper race 264 and the tip 262a of the tubular extension 262.

  A movement restricting means 278 is formed by the upper race 264 and the tip 262a of the tubular extension 262 facing each other with the gap d therebetween.

  Further, when a biased load acts on the support member 272, the deformation of the coil spring on the heavy load side increases, the deformation of the coil spring on the opposite side decreases, and approaches the natural length. The formed lower race 270 can be inclined according to the direction of the load.

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

  When the electric element 210 is energized from the power supply terminal 213, the rotor 216 rotates with the shaft 218 by the magnetic field generated in the stator 214. The eccentric rotation of the eccentric shaft portion 222 accompanying the rotation of the main shaft portion 220 is converted by the connecting means 236 and causes the piston 230 to reciprocate within the cylinder 234. Then, when the compression chamber 248 changes in volume, the refrigerant in the hermetic container 202 is sucked into the compression chamber 248 and compressed.

  In the suction stroke accompanying this compression operation, the refrigerant in the sealed container 202 is intermittently sucked into the compression chamber 248 via the suction muffler 252 and compressed in the compression chamber 248, and then the high-temperature and high-pressure refrigerant is discharged. It is sent to the refrigeration cycle (not shown) from the sealed container 202 via piping or the like.

  The lower end of the shaft 218 is immersed in the lubricating oil 204. When the shaft 218 rotates, the lubricating oil 204 is supplied to each part of the compression element 212 by the oil supply mechanism 228 to lubricate the sliding portion.

  Next, the operation and action of the thrust ball bearing 276 will be described.

  The thrust ball bearing 276 has a very small friction by arranging a plurality of balls 266 of the same size between the flat upper race 264 and the lower race 270 so that each rolls in a point contact state. Therefore, the efficiency of the hermetic compressor can be improved by reducing the sliding loss.

  The load acting on the thrust ball bearing 276 is the mass of the shaft 218 and the rotor 216 and the axial thrust of the electric element 210, and the magnitude thereof is about 10 to 20 N in a general hermetic compressor for a refrigerator. And small.

  In general, there is an appropriate value for the contact load between the ball and the race of the ball bearing. This is because if the contact load is too small, sufficient frictional force does not work between the ball and the race, and slipping occurs, resulting in damage to the surface. Conversely, if the contact load becomes too large, the stress at the contact point between the ball and the race will increase, causing problems such as fatigue failure at the contact part and plastic deformation when the load is extremely large. It is.

  Therefore, specifications such as the diameter and number of balls are selected according to the load conditions so that the contact load of the balls becomes appropriate. For this reason, when the contact load greatly deviates from the load condition assumed in the design, there arises a problem that the life is significantly reduced.

  There are two possible reasons why the contact load of the ball 266 greatly deviates from the design.

  The first is a case where the upper race 264 and the lower race 270 are not kept parallel.

  In the configuration of the cantilever bearing, the shaft 218 can be inclined slightly in the range of the gap between the main shaft portion 220 and the main bearing 226 due to a load due to compression, etc. Even if the inclination is slight, the ball 266 and the upper race 264 and The contact of the lower race 270 can be uneven.

  However, since the lower race 270 seated on the support member 272 can be tilted in any direction with respect to the thrust surface 260 by the support member 272, and the upper race 264 and the lower race 270 can maintain a parallel state, each ball The load acting on 266 can be made uniform, and a reduction in life due to a large load acting on some of the balls 266 or conversely reducing the load can be prevented.

  The second is a case where an external force is applied to the hermetic compressor.

  This is a case where an impact load is applied to the thrust ball bearing 276 due to vibration during transportation, for example. However, since the support member 272 has elasticity to be deformed in the direction of gravity, the support member 272 is deformed. As a result, an increase in the load at the contact portion between the ball 266 and the upper race 264 and the lower race 270 can be mitigated, and the occurrence of plastic deformation such as a depression of the contact portion can be prevented.

  Further, when the downward displacement of the shaft 218 increases and the deformation of the support member 272 increases, the load at the contact portion between the ball 266 and the upper race 264 and the lower race 270 gradually increases, but the amount of displacement increases between the upper race 264 and the tubular shape. When it becomes equal to the gap d of the tip 262a of the extension 262, the support member 272 is further deformed because it includes the movement restricting means 278 formed by the contact between the upper race 264 and the tip 262a of the tubular extension 262. The load at the contact portion between the ball 266 and the upper race 264 and the lower race 270 does not increase any more.

  Further, by making the spring force of the support member 272 when deformed by the gap d smaller than the load resistance of the thrust ball bearing 276, the thrust ball bearing 276 can be more reliably prevented from being damaged.

  Further, by using a plurality of coil springs as the elastic body constituting the support member 272, the stress generated is relatively biased even against repeated deformation, and fatigue failure is unlikely to occur, thereby improving durability. It becomes possible.

  As described above, by using the support member 272, even if the load is biased due to the inclination of the shaft 218 or the load on the thrust ball bearing 276 is increased by an external force, the contact between the ball 266 and the upper race 264 and the lower race 270 is achieved. It is possible to maintain the load within an appropriate range, maintain a good sliding state without wear or plastic deformation at the contact portion, and prevent deterioration in reliability. Further, since the sliding state of the thrust ball bearing 276 is well maintained, the increase in friction is small and the performance improvement effect can be maintained.

  Further, it is possible to prevent the occurrence of noise vibration due to damage to the surface of the contact portion between the ball 266 and the upper race 264 and the lower race 270 and the unstable contact load, thereby maintaining low noise.

  In the present embodiment, the example in which four coil springs are arranged at 90 ° intervals as the supporting member 272 has been described. However, the present invention can be similarly implemented even if five or more coil springs are arranged. The support member 272 may be arranged according to the bias of the acting load.

  Further, although an example in which a coil spring is employed as the support member 272 has been described, the present invention can be similarly applied to other structures having an elastic force as an elastic body with respect to a load acting on the thrust ball bearing 276.

  Further, although the compression element 212 is disposed on the upper side of the electric element 210, the compression element may be provided on the lower side of the electric element. In this case, the thrust ball bearing is usually arranged between the rotor and the upper end of the main bearing.

(Embodiment 3)
FIG. 6 is a longitudinal sectional view of a hermetic compressor according to Embodiment 3 of the present invention. FIG. 7 is an enlarged view of a main part of a thrust ball bearing of the hermetic compressor according to the embodiment.

  In FIGS. 6 and 7, the lubricating oil 304 is stored in the bottom of the sealed container 302, and the compressor body 306 is suspended inside the sealed container 302 by the suspension spring 308. The sealed container 302 is filled with R600a (isobutane), which is a refrigerant with a low warming potential.

  The compressor body 306 includes an electric element 310 and a compression element 312 driven by the electric element 310, and a power supply terminal 313 for supplying power to the electric element 310 is attached to the sealed container 302.

  First, the electric element 310 will be described.

  The electric element 310 includes a stator 314 formed by winding a copper winding around an iron core in which thin plates are laminated, and a rotor 316 disposed on the inner diameter side of the stator 314. Is connected to a power supply (not shown) outside the compressor via a power supply terminal 313 by a conductive wire.

  Next, the compression element 312 will be described.

  The compression element 312 is disposed above the electric element 310.

  The shaft 318 constituting the compression element 312 includes a main shaft portion 320 and an eccentric shaft portion 322 parallel to the main shaft portion 320. A rotor 316 is fixed to the main shaft portion 320.

  The cylinder block 324 includes a main bearing 326 having a cylindrical inner surface, and the main shaft portion 320 is rotatably inserted into and supported by the main bearing 326. The compression element 312 is configured as a cantilever bearing that supports the load acting on the eccentric shaft portion 322 with the main shaft portion 320 and the main bearing 326 arranged below the eccentric shaft portion 322.

  The shaft 318 includes an oil supply mechanism 328 formed of a spiral groove provided on the surface of the main shaft portion 320.

  The cylinder block 324 includes a cylinder 334 that is a cylindrical hole, and a piston 330 is reciprocally inserted into the cylinder 334.

  Further, the connecting means 336 is connected to the eccentric shaft portion 322 and the piston 330 by the hole portions provided at both ends being fitted into the piston pin 338 and the eccentric shaft portion 322 respectively attached to the piston 330.

  A valve plate 346 is attached to the end surface of the cylinder 334 and forms a compression chamber 348 together with the cylinder 334 and the piston 330. Further, the cylinder head 350 is fixed so as to cover the valve plate 346 and cover it. The suction muffler 352 is molded from a resin such as PBT, forms a sound deadening space inside, and is attached to the cylinder head 350.

  Next, the configuration of the thrust ball bearing 376 will be described.

  The main bearing 326 includes a thrust surface 360 that is a flat portion perpendicular to the shaft center, and a tubular extension 362 that extends further upward than the thrust surface 360 and has an inner surface that faces the main shaft portion 320.

  An upper race 364 is disposed on the upper side of the tubular extension 362, and a ball 366, a lower race 370, and a support member held by a holder portion 368 on the outer diameter side of the tubular extension 362 and on the lower side of the upper race 364. 372 is disposed to constitute a thrust ball bearing 376.

  The upper race 364 and the lower race 370 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 368 is formed of a resin material such as polyamide, has an annular shape, and has a plurality of hole portions in which the balls 366 are rotatably accommodated.

  The support member 372 is formed by filling a liquid in an annular tube having flexibility. Specifically, oil is sealed in a tube formed of a flexible material such as rubber.

  On the thrust surface 360, the support member 372, the lower race 370, the ball 366, and the upper race 364 are stacked in contact with each other in this order, and the flange portion 374 of the shaft 318 is seated on the upper surface of the upper race 364.

  When assembled in the hermetic compressor, loads such as the shaft 318 and the rotor 316 are applied to the support member 372 via the lower race 370, and the thrust of the electric element 310 is received during operation. The support member 372 has a spring property in the direction of gravity, and each dimension and the spring of the support member 372 are formed so that a gap d is formed between the upper race 364 and the tip 362a of the tubular extension 362 when a load is applied. Sex is selected.

  A movement restricting means 378 is formed by the upper race 364 and the tip 362a of the tubular extension 362 facing each other through the gap d.

  Further, when a biased load is applied to the support member 372, the deformation on the larger load side is increased, and the deformation on the opposite side is reduced, so that the lower race 370 disposed on the support member 372 has a load. It can be tilted according to the direction.

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

  When the electric element 310 is energized from the power supply terminal 313, the rotor 316 rotates together with the shaft 318 by the magnetic field generated in the stator 314. The eccentric rotation of the eccentric shaft portion 322 accompanying the rotation of the main shaft portion 320 is converted by the connecting means 336 and causes the piston 330 to reciprocate within the cylinder 334. Then, when the volume of the compression chamber 348 changes, the refrigerant in the sealed container 302 is sucked into the compression chamber 348 and compressed.

  In the suction stroke accompanying this compression operation, the refrigerant in the sealed container 302 is intermittently sucked into the compression chamber 348 via the suction muffler 352 and compressed in the compression chamber 348, and then the high-temperature and high-pressure refrigerant is discharged. It is sent to a refrigeration cycle (not shown) from the sealed container 302 via a pipe or the like.

  The lower end of the shaft 318 is immersed in the lubricating oil 304. When the shaft 318 rotates, the lubricating oil 304 is supplied to each part of the compression element 312 by the oil supply mechanism 328 to lubricate the sliding portion.

  Next, the operation and action of the thrust ball bearing 376 will be described.

  Thrust ball bearing 376 has a very small friction by arranging a plurality of balls 366 of the same size between flat upper race 364 and lower race 370 so that each rolls in a point contact state. Therefore, the efficiency of the hermetic compressor can be improved by reducing the sliding loss.

  The load acting on the thrust ball bearing 376 is the mass of the shaft 318 and the rotor 316 and the axial thrust of the electric element 310, and the magnitude thereof is about 10 to 20 N in a general hermetic compressor for a refrigerator. And small.

  In general, there is an appropriate value for the contact load between the ball and the race of the ball bearing. This is because if the contact load is too small, sufficient frictional force does not work between the ball and the race, and slipping occurs, resulting in damage to the surface. Conversely, if the contact load becomes too large, the stress at the contact point between the ball and the race will increase, causing problems such as fatigue failure at the contact part and plastic deformation when the load is extremely large. It is.

  Therefore, specifications such as the diameter and number of balls are selected according to the load conditions so that the contact load of the balls becomes appropriate. For this reason, when the contact load greatly deviates from the load condition assumed in the design, there arises a problem that the life is significantly reduced.

  There are two possible reasons why the contact load of the ball 166 greatly deviates from the design.

  First, the upper race 364 and the lower race 370 are not kept parallel.

  In the configuration of the cantilever bearing, the shaft 318 can be slightly inclined in the range of the gap between the main shaft portion 320 and the main bearing 326 due to a load due to compression, and the ball 366 and the upper race 364 and the The contact of the lower race 370 can be uneven.

  However, the lower race 370 seated on the support member 372 can be tilted in any direction with respect to the thrust surface 360 by the support member 372, and the upper race 364 and the lower race 370 can be maintained in a parallel state. The load acting on 366 can be made uniform, and a reduction in life due to a large load acting on some of the balls 366 or conversely reducing the load can be prevented.

  The second is a case where an external force is applied to the hermetic compressor.

  This is a case where an impact load is applied to the thrust ball bearing 376 due to vibration during transportation, for example. However, since the support member 372 has elasticity to be deformed in the direction of gravity, the support member 372 is deformed. As a result, an increase in the load at the contact portion between the ball 366 and the upper race 364 and the lower race 370 can be alleviated, and the occurrence of plastic deformation such as a depression of the contact portion can be prevented.

  Further, when the downward displacement of the shaft 318 is increased and the deformation of the support member 372 is increased, the load at the contact portion between the ball 366 and the upper race 364 and the lower race 370 gradually increases. When the clearance d becomes equal to the gap d of the distal end 362a of the extension portion 362, the support member 372 is further deformed because it includes the movement restricting means 178 formed by the contact between the upper race 364 and the distal end 362a of the tubular extension portion 362. The load at the contact portion between the ball 366 and the upper race 364 and the lower race 370 does not increase any more.

  Furthermore, since the support member 372 is formed by filling a flexible annular tube with a liquid and has a large attenuation, noise such as a rubbing sound accompanying deformation of the support member 372 hardly occurs. Further, since the sliding sound generated by the thrust ball bearing 376 is also easily attenuated, the noise of the compressor can be reduced.

  As described above, by using the support member 372, even if the load is biased due to the inclination of the shaft 318 or the load on the thrust ball bearing 376 is increased by an external force, the contact between the ball 366 and the upper race 364 and the lower race 370 is achieved. It is possible to maintain the load within an appropriate range, maintain a good sliding state without wear or plastic deformation at the contact portion, and prevent deterioration in reliability. Further, since the sliding state of the thrust ball bearing 376 is maintained well, the increase in friction is small and the performance improvement effect can be maintained.

  Further, it is possible to prevent the occurrence of noise vibration due to the damage to the surface of the contact portion between the ball 366 and the upper race 364 and the lower race 370 and the unstable contact load, and the low noise can be maintained.

  In the present embodiment, the compression element 312 is disposed above the electric element 310, but the compression element may be disposed below the electric element. In this case, the thrust ball bearing is usually arranged between the rotor and the upper end of the main bearing.

  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.

1 is a longitudinal sectional view of a hermetic compressor according to Embodiment 1 of the present invention. The principal part enlarged view of the thrust ball bearing of the hermetic compressor in the same embodiment External view of support member of hermetic compressor in the same embodiment Vertical sectional view of a hermetic compressor according to Embodiment 2 of the present invention The principal part enlarged view of the thrust ball bearing of the hermetic compressor in the same embodiment Vertical sectional view of a hermetic compressor according to Embodiment 3 of the present invention The principal part enlarged view of the thrust ball bearing of the 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 A perspective view of a support member of a conventional hermetic compressor

Explanation of symbols

102, 202, 302 Sealed container 104, 204, 304 Lubricating oil 110, 210, 310 Electric element 112, 212, 312 Compression element 114, 214, 314 Stator 116, 216, 316 Rotor 118, 218, 318 Shaft 120, 220, 320 Main shaft portion 122, 222, 322 Eccentric shaft portion 124, 224, 324 Cylinder block 126, 226, 326 Main bearing 130, 230, 330 Piston 136, 236, 336 Connecting means 148, 248, 348 Compression chamber 160, 260 , 360 Thrust surface 164, 264, 364 Upper race 166, 266, 366 Ball 168, 268, 368 Holder part 170, 270, 370 Lower race 172, 272, 372 Support member 172a, 172b, 172c Upper convex part 172 , 172e, 172f under the convex portion 176,276,376 thrust ball bearings 178,278,378 movement restriction means

Claims (6)

Lubricating oil is stored in a sealed container, and an electric element having a stator and a rotor and a compression element driven by the electric element are accommodated, and the compression element is a main shaft portion to which the rotor is fixed. And a shaft having an eccentric shaft portion, a cylinder block having a compression chamber, a piston reciprocating in the compression chamber, a connecting means for connecting the piston and the eccentric shaft portion, and the cylinder block. A main bearing that supports the main shaft portion; and a thrust ball bearing disposed on a thrust surface of the main bearing, the thrust ball bearing comprising: a plurality of balls held by a holder portion; And a support portion having an elastic force in the direction of gravity between the lower race or the upper race and the thrust surface. Arranged and provided with movement restricting means for restricting the movement of the gravity direction lower side of the shaft, before the load exceeds the load capacity is applied to the thrust ball bearing, the movement limiting means is characterized in that the function Hermetic compressor. The hermetic compression according to claim 1, wherein when the elastic deformation of a part of the support member is increased, the other part of the elastic deformation is reduced, so that the thrust ball bearing can be inclined with respect to the thrust surface. Machine. The support member is an annular wave washer, and includes a plurality of upper convex portions that protrude toward the lower race and come into contact with the lower race, and a plurality of lower convex portions that protrude toward the thrust surface and come into contact with the thrust surface. The hermetic compressor according to claim 1 or 2, wherein the convex portions and the lower convex portions are alternately arranged in a circumferential direction. The hermetic compressor according to claim 3, wherein the support member is formed by stacking a plurality of wave washers having the same shape. The hermetic compressor according to claim 1, wherein the support member is formed by arranging a plurality of elastic bodies in the circumferential direction. The hermetic compressor according to claim 1, wherein the support member is formed of an annular tube filled with fluid and having flexibility.