JP2014020217A - Compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor capable of flexion of a shaft.SOLUTION: A compressor comprises: a stator; a rotor 30 arranged inside the stator; a shaft 7 fixed to the rotor 30 and having an eccentric section for driving a compression mechanism 6; an upper balance weight 41 arranged on an upper face 30U (first end face) on the same side as a center of the eccentric section to a rotation shaft O when seen from a rotation shaft direction of the shaft 7; and a lower balance weight 42 arranged on a lower end face (second end face) at a position at which a phase is different from that of the upper balance weight 41 by 180 degrees. A first lift force generating member (upper balance weight 41) for generating a lift force in a direction toward the rotation shaft O together with rotation of the rotor 30 is provided on an upper end face 30L on the same side as the center of the eccentric section to the rotation shaft O when seen from the rotation shaft direction of the shaft 7.

Description

  The present invention relates to a compressor including a rotor to which a shaft having an eccentric portion that drives a compression mechanism is fixed, and a balance weight disposed on an end surface in the axial direction of the rotor.

  2. Description of the Related Art Conventionally, a compressor having a configuration in which a driving force of a motor is transmitted to a compression mechanism via a shaft having an eccentric portion is known (see, for example, Patent Document 1). The center part of the eccentric part is eccentric with respect to the rotating shaft, and a roller of the compression mechanism is mounted. The roller is disposed in the compression chamber of the cylinder. As the shaft rotates, the volume of the space in the compression chamber partitioned by the roller changes and the refrigerant is compressed. The motor includes a rotor to which a shaft is fixed and a stator disposed on the outer peripheral side of the rotor.

  In such a compressor, in order to prevent an imbalance in rotational balance due to the eccentric rotation between the eccentric portion and the rotor, balance weights are attached to both end surfaces in the axial direction of the rotor with a phase shift of 180 °. Then, the rotational balance is achieved by canceling out the centrifugal force and the rotational moment acting on the eccentric portion and the rotor by the centrifugal force and the rotational moment generated in the balance weight.

  Further, for example, in the compressor described in Patent Document 2, a balance weight is attached to the opposite side of the shaft having the eccentric portion from the side fixed to the rotor. The balance weight has an airfoil shape in cross section orthogonal to the shaft, and generates lift in the same direction as the direction of centrifugal force acting on the balance weight as the shaft rotates. As a result, it is described that the generated lift promotes centrifugal force, and the balance weight can be reduced in size and weight.

Japanese Patent Laid-Open No. 9-200986 Japanese Patent Application Laid-Open No. 2002-339884

  However, in the compressor described in Patent Document 1, there is a problem that the shaft bends due to the centrifugal force generated in the balance weight attached to the end surface far from the eccentric portion when the rotor rotates. In particular, when the deflection of the shaft increases due to high-speed rotation of the rotor, the shaft may come into contact with the bearing portion, or the rotor and the stator may come into contact with each other, and sound vibration may occur.

  Further, in the compressor described in Patent Document 2, the direction of the lift generated by the balance weight is the same as the direction of action of the centrifugal force generated by the balance weight. Therefore, this occurs when the shaft is bent by the centrifugal force. Lift increases the shaft deflection.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a compressor capable of reducing the deflection of the shaft.

  In order to solve the above problems, a compressor according to a first invention includes a stator, a rotor disposed inside the stator, a shaft that is fixed to the rotor and has an eccentric portion that drives a compression mechanism. A first balance weight disposed on the same side as the central portion of the eccentric portion with respect to the rotation axis when viewed from the rotation axis direction of the shaft, on the first end surface opposite to the compression mechanism in the rotor; The second end surface of the rotor on the compression mechanism side includes a second balance weight disposed at a position that is 180 degrees out of phase with the first balance weight, and the first end surface is viewed from the rotation axis direction. A first lift generating member that generates lift in a direction toward the rotation shaft as the rotor rotates is provided on the same side as the central portion of the eccentric portion with respect to the rotation shaft. Vignetting wherein the are.

  In this compressor, the first end face can generate lift in the direction toward the rotation axis of the shaft, so that the generated lift and the centrifugal force generated by the first balance weight cancel each other out, and the shaft due to this centrifugal force cancels. Deflection can be reduced. As a result, it is possible to suppress the shaft from coming into contact with the bearing portion and the rotor from coming into contact with the stator, and to reduce the sound vibration generated by these contacts.

  In a compressor according to a second aspect based on the first aspect, the first lift generating member is provided in a region outside the intermediate portion between the rotating shaft and the outer peripheral surface of the rotor at the first end surface. It is characterized by.

  In this compressor, the first lift generating member is provided in a region outside the intermediate portion between the rotating shaft and the outer peripheral surface of the rotor. At the first end face, the rotational speed increases as it goes from the inner peripheral face of the rotor to the outer peripheral face. Therefore, the first lift generating member is provided in a region outside the intermediate portion, thereby generating more lift. be able to. As a result, lift can be generated efficiently.

  A compressor according to a third invention is characterized in that, in the first or second invention, the first lift generating member is an airfoil.

  In this compressor, since the first lift generating member is an airfoil, the drag generated in the first lift generating member can be reduced and the lift can be generated efficiently.

  A compressor according to a fourth invention is characterized in that, in any one of the first to third inventions, the first lift generating member and the first balance weight are the same member.

  In this compressor, since the first lift generating member and the first balance weight are the same member, the first lift generating member is compared with a case where the first lift generating member is different from the first balance weight. It is possible to suppress an increase in cost due to the arrangement. Further, even when the installation space is limited, the first lift generating member can be arranged.

  The compressor according to a fifth aspect of the present invention is the compressor according to any one of the first to fourth aspects, wherein the second end surface is opposite to the central portion of the eccentric portion with respect to the rotational shaft when viewed from the rotational shaft direction. Is provided with a second lift generating member that generates a lift in a direction opposite to the direction toward the rotation axis as the rotor rotates.

  In this compressor, the second lift generating member can generate lift in the direction opposite to the direction toward the rotation axis of the shaft at the second end surface, and thus the generated lift and the centrifugal force generated by the first balance weight are generated. By canceling out, it becomes possible to further reduce the deflection of the shaft due to this centrifugal force.

  In a compressor according to a sixth aspect based on the fifth aspect, the second lift generating member is provided in a region outside the intermediate portion between the rotating shaft and the outer peripheral surface of the rotor at the second end surface. It is characterized by.

  In this compressor, the second lift generating member is provided in a region outside the intermediate portion between the rotating shaft and the outer peripheral surface of the rotor. At the second end surface, since the rotational speed increases from the inner peripheral surface of the rotor toward the outer peripheral surface, the second lift generating member is provided in a region outside the intermediate portion, thereby generating more lift. be able to. As a result, lift can be generated efficiently.

  In a compressor according to a seventh aspect based on the fifth or sixth aspect, the second lift generating member is an airfoil.

  In this compressor, since the second lift generating member is an airfoil, the drag generated in the second lift generating member can be reduced and the lift can be generated efficiently.

  In the compressor according to an eighth aspect of the invention, the second lift generating member and the second balance weight are the same member.

  In this compressor, since the second lift generating member and the second balance weight are the same member, the second lift generating member is compared with the case where the second lift generating member is different from the second balance weight. It is possible to suppress an increase in cost due to the arrangement. Further, even when the installation space is limited, the second lift generating member can be arranged.

  As described above, according to the present invention, the following effects can be obtained.

  In the first aspect of the invention, the first end face can generate lift in the direction toward the rotation axis of the shaft, so that the generated lift and the centrifugal force generated by the first balance weight cancel each other, and the shaft due to this centrifugal force Can be reduced. As a result, it is possible to suppress the shaft from coming into contact with the bearing portion and the rotor from coming into contact with the stator, and to reduce the sound vibration generated by these contacts.

  In the second invention, the first lift generating member is provided in a region outside the intermediate portion between the rotating shaft and the outer peripheral surface of the rotor. At the first end face, the rotational speed increases as it goes from the inner peripheral face of the rotor to the outer peripheral face. Therefore, the first lift generating member is provided in a region outside the intermediate portion, thereby generating more lift. be able to. As a result, lift can be generated efficiently.

  In the third aspect of the invention, since the first lift generating member is an airfoil, the drag generated on the first lift generating member can be reduced and the lift can be generated efficiently.

  In the fourth invention, since the first lift generating member and the first balance weight are the same member, the first lift generating member is generated as compared with the case where the first lift generating member is different from the first balance weight. Cost increase due to the arrangement of the members can be suppressed. Further, even when the installation space is limited, the first lift generating member can be arranged.

  In the fifth aspect of the invention, the lift in the direction opposite to the direction toward the rotation axis of the shaft can be generated by the second lift generating member on the second end face, and thus the generated lift and the centrifugal force generated by the first balance weight And the deflection of the shaft due to the centrifugal force can be further reduced.

  In the sixth invention, the second lift generating member is provided in a region outside the intermediate portion between the rotating shaft and the outer peripheral surface of the rotor. At the second end surface, since the rotational speed increases from the inner peripheral surface of the rotor toward the outer peripheral surface, the second lift generating member is provided in a region outside the intermediate portion, thereby generating more lift. be able to. As a result, lift can be generated efficiently.

  In the seventh invention, since the second lift generating member is an airfoil, the drag generated in the second lift generating member can be reduced, and the lift can be generated efficiently.

  In the eighth invention, since the second lift generating member and the second balance weight are the same member, the second lift generating member is compared with the case where the second lift generating member is different from the second balance weight. Cost increase due to the arrangement of the members can be suppressed. Further, even when the installation space is limited, the second lift generating member can be arranged.

It is a longitudinal section of a compressor concerning an embodiment of the present invention. It is the figure which looked at the drive mechanism shown in FIG. 1 from the upper part. It is the figure which showed the balance of the force of the drive mechanism shown in FIG. 1, and a shaft. It is a figure which shows the modification of the balance weight shown in FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to FIGS. 1 to 3.

[Compressor 1]
As shown in FIG. 1, the compressor 1 accommodates a compression mechanism 6 that compresses a refrigerant, a drive mechanism 8 that is disposed above the compression mechanism 6 and drives the compression mechanism 6 via a shaft 7, and the like. A casing 2 is provided. The compressor 1 compresses the refrigerant (for example, CO 2) introduced from the suction pipe 3 and discharges it from the discharge pipe 4. The compressor 1 is used by being incorporated in a refrigeration cycle such as an air conditioner, for example, and is installed in the direction shown in FIG. 1, that is, the direction in which the shaft 7 is in the vertical direction.

  An upper portion of the casing 2 is provided with a discharge pipe 4 for discharging the refrigerant compressed by the compression mechanism 6 and a terminal terminal 5 for supplying a current to a coil 23 of a stator 20 described later of the drive mechanism 8. ing. In FIG. 1, the wiring for connecting the coil 23 and the terminal terminal 5 is omitted. Further, a suction pipe 3 for introducing a refrigerant into the compressor 1 is provided on a side portion of the casing 2. Lubricating oil L for smoothing the operation of the sliding portion of the compression mechanism 6 and sealing the gap of the compression mechanism 6 is stored at the bottom of the casing 2.

[Compression mechanism 6]
The compression mechanism 6 includes a cylinder 11, a piston 12 disposed inside the cylinder 11, a front head 13 disposed above the cylinder 11, a muffler member 14 disposed above the front head 13, and the cylinder 11. And a rear head 15 disposed on the lower side.

  A compression chamber 11 a that is a circular hole is formed at the center of the cylinder 11. Further, the cylinder 11 is formed with a suction passage 11b for introducing the refrigerant supplied from the suction pipe 3 into the compression chamber 11a. The shaft 7 has an eccentric part 7a at a position in the compression chamber 11a. The eccentric part 7 a is substantially cylindrical, and the center part (the central axis of the eccentric part 7 a) is eccentric with respect to the rotation center of the shaft 7, that is, the rotation axis O of the shaft 7.

  The piston 12 includes an annular roller 12a mounted on the eccentric portion 7a of the shaft 7, and a blade (not shown) that protrudes radially outward from the outer peripheral surface of the roller 12a and is supported by the cylinder 11 so as to be swingable. Composed. When the shaft 7 is rotated, the roller 12a of the piston 12 rotates around the rotation axis of the shaft 7 with its outer peripheral portion being in contact with the inner peripheral surface of the compression chamber 11a. Thereby, since the volume of the two spaces in the compression chamber 11a partitioned by the piston 12 changes, the refrigerant is compressed in the compression chamber 11a.

  The front head 13 is fixed to the inner peripheral surface of the casing 2. A discharge hole (not shown) for discharging the refrigerant compressed in the compression chamber 11a is formed in the front head 13, and a valve mechanism (not shown) that opens and closes the outlet of the discharge hole is formed on the upper surface of the front head 13. ) Is attached. Further, an oil return hole (not shown) for allowing refrigerant and lubricating oil to pass therethrough is formed in the outer peripheral portion of the front head 13 so as to penetrate in the vertical direction.

  The muffler member 14 is attached to the upper surface of the front head 13 so as to cover the valve mechanism. Due to the muffler space formed between the muffler member 14 and the front head 13, noise associated with the discharge of the refrigerant is reduced. The muffler member 14 is formed with a discharge port (not shown) for discharging the refrigerant in the muffler space.

  When the refrigerant pressure in the compression chamber 11a becomes equal to or higher than a predetermined pressure, the valve mechanism provided in the front head 13 opens, and the refrigerant and lubricating oil in the compression chamber 11a are discharged into the muffler space. Then, the refrigerant discharged from the muffler space moves above the drive mechanism 8 through the air gap 8 a between the rotor 30 and the stator 20.

[Drive mechanism 8]
The drive mechanism 8 includes a substantially cylindrical stator 20 fixed to the inner peripheral surface of the casing 2, a cylindrical rotor 30 disposed on the radially inner side of the stator 20 via an air gap 8 a, An upper balance weight 41 (first balance weight, first lift generating member) disposed on the upper end surface 30U (first end surface) and a lower balance weight 42 (arranged on the lower end surface 30L (second end surface) of the rotor 30 ( A second balance weight and a second lift generating member).

  The stator 20 is wound around a substantially cylindrical stator core 21 fixed to the inner peripheral surface of the casing 2, insulators 22 attached to both upper and lower ends of the stator core 21, and inner peripheral portions of the stator core 21 and the insulator 22. And a coil 23. A plurality of grooves (not shown) extending in the vertical direction are formed on the outer peripheral portion of the stator core 21, and the refrigerant and the lubricating oil pass between the grooves and the casing 2. The insulator 22 is provided to insulate the stator core 21 and the coil 23 from each other.

  The rotor 30 is integrally attached to a cylindrical rotor core 31 that fixes the outer peripheral surface of the shaft 7, a plurality of permanent magnets (not shown) embedded in the rotor core 31, and upper and lower ends of the rotor core 31. And annular end plates 32, 32. The rotor 30 rotates together with the shaft 7 by the electromagnetic force generated by the current flowing through the coil 23 and the magnetic flux generated in the rotor core 31.

  The upper and lower balance weights 41 and 42 are both made of a non-magnetic material and are provided to prevent rotational balance imbalance due to eccentric rotation of the eccentric portion 7a and the roller 12a. The upper balance weight 41 disposed on the upper end surface 30U of the rotor 30 is on the same side as the central portion of the eccentric portion 7a (the central axis of the eccentric portion 7a) with respect to the rotational axis O when viewed from the rotational axis direction of the shaft 7. Has been placed. On the other hand, the lower balance weight 42 disposed on the lower end surface 30L of the rotor 30 is the side opposite to the center portion of the eccentric portion 7a with respect to the rotation axis O when viewed from the rotation axis direction of the shaft 7 (ie, the upper balance weight 41). And 180 degrees out of phase). Then, the centrifugal balance and the rotational moment acting on the shaft 7 and the rotor 30 are canceled out by the centrifugal force and the rotational moment generated in the upper and lower balance weights 41 and 42, thereby achieving a rotational balance. The lower balance weight 42 is thicker than the upper balance weight 41 and is heavier than the upper balance weight 41.

  Further, as shown in FIG. 2, the upper and lower balance weights 41 and 42 have a wing shape when viewed from the rotation axis direction of the shaft 7. As a result, the upper and lower balance weights 41 and 42 generate lift by receiving a fluid flow V (mainly due to the refrigerant) generated as the rotor 30 rotates.

  The upper balance weight 41 has two streamline chords 41I that connect a front edge 41F located in front of the rotor 30 in the rotation direction (arrow R direction in FIG. 2) and a rear edge 41B located in the rear in the rotation direction. , 41O to form a streamlined airfoil shape. The chord 41I located on the inner peripheral side of the rotor 30 is curved such that the front edge 41F side swells in a direction toward the inner peripheral side of the rotor 30. Further, the trailing edge 41 </ b> B side of the chord 41 </ b> I is curved toward the outer peripheral side of the rotor 30 so that the direction of fluid flow faces the outer peripheral side of the rotor 30. On the other hand, the chord 41O located on the outer peripheral side of the rotor 30 is curved in the direction toward the inner peripheral side of the rotor 30 on the front edge 41F side, and on the outer peripheral side of the rotor 30 on the rear edge 41B side, like the chord 41I. Although curved, the magnitude of the curvature is small compared to the chord 41I.

  By forming the upper balance weight 41 as described above, the upper balance weight 41 generates a lift L1 that faces the inner side in the radial direction of the rotor 30. This lift L1 is obtained as a component perpendicular to the fluid flow of the acting force generated by the pressure difference between the fluids passing through the inside and outside of the chords 41I and 41O. The lift L1 is directed in the direction opposite to the direction in which the centrifugal force F1 generated by the upper balance weight 41 acts (the direction in which the centrifugal force F1 cancels out). A drag force is generated in the direction parallel to the fluid flow.

  On the other hand, the lower balance weight 42 is composed of two streamlined blades connecting a front edge 42F positioned in front of the rotor 30 in the rotation direction (arrow R direction in FIG. 2) and a rear edge 42B positioned rearward in the rotation direction. A streamlined airfoil shape is formed by the strings 42I and 42O. The lower balance weight 42 has the same shape in plan view as the upper balance weight 41. However, the attachment direction of the lower balance weight 42 is different from that of the upper balance weight 41. The chord 42O located on the outer peripheral side of the rotor 30 is curved along the outer periphery of the rotor 30. Further, the chord 42I located on the inner peripheral side of the rotor 30 is curved along the outer periphery of the rotor 30 like the chord 42O, but the magnitude of the curvature is smaller than that of the chord 42I.

  By forming the lower balance weight 42 as described above, the lower balance weight 42 generates a lift L2 that faces the outer side of the rotor 30 in the radial direction. This lift L2 is obtained as a component perpendicular to the fluid flow of the acting force generated by the pressure difference of the fluid passing through the inside and outside of the chords 42I and 42O. The lift L2 is directed in the direction opposite to the direction in which the centrifugal force F1 generated by the upper balance weight 41 acts (the direction in which the centrifugal force F1 cancels out). A drag force is generated in the direction parallel to the fluid flow.

  The lifts L1 and L2 generated in this way cancel each other with the centrifugal force F1 generated by the upper balance weight 41. As a result, the deflection of the shaft 7 due to the centrifugal force F1 can be reduced.

  Here, with reference to FIG. 3, the principle that the deflection of the shaft 7 is reduced by generating the lifts L <b> 1 and L <b> 2 in the direction opposite to the direction of action of the centrifugal force F <b> 1 will be briefly described.

  The sizes of the upper and lower balance weights 41 and 42 are designed in accordance with, for example, a predetermined motor rotation speed. At this predetermined motor rotational speed (predetermined rotational speed of the rotor 30), centrifugal force and rotational moment generated in the eccentric part 7a of the shaft 7, the piston 12 and the rotor 30, and the upper and lower balance weights 41 and 42 are generated. Centrifugal force and rotational moment are balanced.

  Therefore, when the rotational speed of the rotor 30 is a normal rotational speed (a speed close to the predetermined rotational speed), centrifugal force and rotational moment generated in the eccentric portion 7a of the shaft 7, the piston 12, and the rotor 30, The centrifugal force generated in the upper and lower balance weights 41 and 42 is balanced with the rotational moment, so that the shaft 7 hardly bends. At normal rotational speed, the lifts L1 and L2 generated by the upper and lower balance weights 41 and 42 are small, and the contribution to this balance is small.

  On the other hand, when the rotor 30 rotates at a high speed (rotates beyond a predetermined rotation speed), the centrifugal forces F1 and F2 generated in the upper and lower balance weights 41 and 42 increase, and the rotational moment also increases. In particular, the rotational moment on the upper balance weight 41 side far from the compression mechanism 6 becomes very large. As a result, the centrifugal force and rotational moment generated in the eccentric portion 7a of the shaft 7, the piston 12 and the rotor 30 and the centrifugal force and rotational moment generated in the upper and lower balance weights 41 and 42 are not balanced, as shown in FIG. Further, the shaft 7 is largely bent toward the upper balance weight 41 with respect to the axial direction O by the centrifugal force F1.

  Therefore, in the present application, the upper and lower balance weights 41 and 42 generate lift forces L1 and L2 in the direction opposite to the centrifugal force F1, thereby suppressing the deflection of the shaft 7. Since the lifts L1 and L2 are proportional to the square of the speed, a large lift can be obtained when the rotor 30 rotates at a high speed. The lift L2 generated by the lower balance weight 42 is a force that assists the lift L1. For example, if the deflection of the shaft 7 can be sufficiently suppressed by the lift L1, it is not necessary to generate the lift L2.

  Returning to FIG. 2, the upper and lower balance weights 41, 42 are both regions S outside the intermediate portion M (the portion indicated by the one-dot chain line in FIG. 2) between the rotating shaft O and the outer peripheral surface 30 b of the rotor 30. Is provided. The distance between the rotation axis O and the intermediate portion M and the distance between the intermediate portion M and the outer peripheral surface 30b of the rotor 30 are the same.

  The upper and lower balance weights 41 and 42 have rivets (not shown) in rivet insertion holes (not shown) formed in the upper and lower balance weights 41 and 42, the end plates 32 and 32, and the rotor core 31. By being inserted, it is fixed to the rotor 30. However, the fixing method is not particularly limited, and the upper and lower balance weights 41 and 42 may be fixed to the rotor 30 using screws. The rotor core 31 and the end plates 32, 32 are formed with a plurality of ventilation holes (not shown) that allow the refrigerant and the lubricating oil to pass therethrough in the rotational axis direction of the shaft 7.

[Characteristics of Compressor of this Embodiment]
The compressor of this embodiment has the following characteristics. In the compressor 1 according to the present embodiment, the shaft 7 is rotated on the same side as the first balance weight (upper balance weight 41) with respect to the rotation axis O of the shaft 7 on the upper end surface 30U of the rotor 30 as the rotor 30 rotates. A first lift generating member (upper balance weight 41) for generating lift in a direction toward the rotation axis O is provided. Therefore, the direction of the lift generated at the upper end surface 30U is opposite to the direction of the centrifugal force generated by the first balance weight, and the lift and the centrifugal force cancel each other, thereby reducing the deflection of the shaft 7 due to the centrifugal force. it can. As a result, contact of the shaft with the bearing portion and contact between the rotor and the stator are suppressed, and sound vibration generated by such contact can be suppressed.

  In the compressor 1 of the present embodiment, the first lift generating member (upper balance weight 41) is higher than the intermediate portion M between the rotation axis O of the shaft 7 and the outer periphery of the rotor 30 on the upper end surface 30 </ b> U of the rotor 30. It is provided in the outer region S. In the upper end surface 30U, the rotational speed increases from the inner peripheral surface 30a of the rotor 30 toward the outer peripheral surface 30b. Therefore, the first lift generating member is provided in the region S outside the intermediate portion M. More lift can be generated. As a result, lift can be generated efficiently.

  Further, in the compressor 1 of the present embodiment, the first lift generating member (upper balance weight 41) is an airfoil. Therefore, the drag generated in the first lift generating member can be reduced, and lift can be generated efficiently.

  In the compressor 1 of the present embodiment, the first lift generating member and the first balance weight are the same member (upper balance weight 41). Therefore, the cost increase by arrange | positioning a 1st lift generation member can be suppressed compared with the case where a 1st lift generation member is arrange | positioned as a member different from a 1st balance weight. Even when the space of the upper end surface 30U of the rotor 30 is limited, the first lift generating member can be arranged.

  Further, in the compressor 1 of the present embodiment, with the rotation of the rotor 30, the lower end surface 30 </ b> L of the rotor 30 is on the same side as the second balance weight (lower balance weight 42) with respect to the rotation axis O of the shaft 7. A second lift generating member (lower balance weight 42) that generates lift in a direction opposite to the direction of the shaft 7 toward the rotation axis O is provided. Therefore, the direction of the lift generated at the lower end surface 30L is opposite to the direction of the centrifugal force generated by the first balance weight, and the lift and the centrifugal force cancel each other, thereby further reducing the deflection of the shaft 7 due to the centrifugal force. It becomes possible to reduce.

  In the compressor 1 of the present embodiment, the second lift generating member (lower balance weight 42) is lower than the intermediate portion M between the rotation axis O of the shaft 7 and the outer periphery of the rotor 30 at the lower end surface 30 </ b> L of the rotor 30. It is provided in the outer region S. In the lower end surface 30L, the rotational speed increases as it goes from the inner peripheral surface 30a of the rotor 30 to the outer peripheral surface 30b. Therefore, the second lift generating member is provided in the region S outside the intermediate portion M. More lift can be generated. As a result, lift can be generated efficiently.

  Further, in the compressor 1 of the present embodiment, the second lift generating member (lower balance weight 42) is an airfoil. Therefore, the drag generated in the second lift generating member can be reduced, and lift can be generated efficiently.

  In the compressor 1 of the present embodiment, the second lift generating member and the second balance weight are the same member (lower balance weight 42). Therefore, the cost increase by arrange | positioning a 2nd lift generation member can be suppressed compared with the case where a 2nd lift generation member is arrange | positioned as a member different from a 2nd balance weight. Even when the space of the lower end surface 30L of the rotor 30 is limited, the second lift generating member can be arranged.

  As mentioned above, although embodiment of this invention was described, it should be thought that the specific structure of this invention is not limited to the said embodiment. The scope of the present invention is shown not only by the description of the above-described embodiment but also by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

[Modification]
In the present embodiment, the upper balance weight 41 serves as both the first balance weight and the first lift generation member, and the lower balance weight 42 serves as the second balance weight and the second lift generation member. However, the first balance weight and the first lift generating member may be separate members, and the second balance weight and the second lift generating member may be separate members.

  However, in such a case, the first lift generating member is the same as the first balance weight (relative to the rotation axis O) as viewed from the rotation axis direction of the shaft 7 from the viewpoint of generating the lift L1 in the direction to cancel the centrifugal force F1. It is necessary to be disposed on the same side as the central portion of the eccentric portion 7a. Further, the second lift generating member is disposed on the same side as the second balance weight (opposite to the central portion of the eccentric portion 7a with respect to the rotation axis O) when viewed from the rotation axis direction of the shaft 7. Cost.

  Further, the second lift generating member may not be provided. That is, the lower balance weight is a normal balance weight (one that does not generate lift, or one that is small even when lift is generated), and the lift generation member does not exist as a separate member.

  In the present embodiment, the upper and lower balance weights 41 and 42 are airfoils, and the upper and lower balance weights 41 and 42 have the same shape. However, the shape and the like of the upper and lower balance weights 41 and 42 may be different. Further, the shape of the upper and lower balance weights 41 and 42 is not limited to the airfoil, and can be various shapes within a range in which lift can be generated in the above-described direction.

  For example, as shown in FIG. 4, the upper and lower balance weights are rectangular plate-like members in plan view, and are arranged at predetermined angles θ1 and θ2 with respect to the direction of the fluid flow V. (Θ1 and θ2 are also referred to as elevation angles). In this case, the upper balance weight 41 'is disposed so as to be separated from the shaft 7 from the front in the rotation direction (the direction of arrow R in FIG. 4) toward the rear in the rotation direction. Further, the lower balance weight 42 ′ is disposed so as to be closer to the shaft 7 from the front in the rotation direction (arrow R direction in FIG. 4) toward the rear in the rotation direction. The magnitudes of the elevation angles θ1 and θ2 are not particularly limited, but are at least 45 ° or less, for example, 5 ° to 10 °, from the viewpoint of drag reduction and suppression of eddy currents.

  In the present embodiment, the upper and lower balance weights 41 and 42 are provided in the region S outside the intermediate portion M between the rotation shaft O and the outer peripheral surface 30b of the rotor 30. It is not limited to S.

  If the present invention is used, the deflection of the shaft of the compressor can be reduced.

DESCRIPTION OF SYMBOLS 1 Compressor 6 Compression mechanism 7 Shaft 7a Eccentric part 20 Stator 30 Rotor 30U Upper end surface (1st end surface)
30L Lower end surface (second end surface)
41 Upper balance weight (first balance weight, first lift generating member)
42 Lower balance weight (second balance weight, second lift generating member)

Claims (8)

A stator,
A rotor disposed inside the stator;
A shaft fixed to the rotor and having an eccentric portion for driving a compression mechanism;
A first balance weight disposed on the same side as the central portion of the eccentric portion with respect to the rotation axis as viewed from the rotation axis direction of the shaft, on the first end surface of the rotor opposite to the compression mechanism;
A second balance weight disposed at a position 180 degrees out of phase with the first balance weight on the second end surface of the rotor on the compression mechanism side;
With
In the first end face, on the same side as the central part of the eccentric part with respect to the rotational axis as seen from the rotational axis direction,
The compressor characterized by the 1st lift generation member which generates the lift of the direction which goes to the said rotating shaft with rotation of the said rotor.   2. The compressor according to claim 1, wherein the first lift generating member is provided in a region outside an intermediate portion between the rotating shaft and the outer peripheral surface of the rotor on the first end surface.   The compressor according to claim 1, wherein the first lift generating member is an airfoil.   The compressor according to any one of claims 1 to 3, wherein the first lift generating member and the first balance weight are the same member. In the second end face, on the side opposite to the central part of the eccentric part with respect to the rotational axis as seen from the rotational axis direction,
The compressor according to any one of claims 1 to 4, wherein a second lift generation member that generates a lift in a direction opposite to a direction toward the rotation shaft as the rotor rotates is provided.   The compressor according to claim 5, wherein the second lift generating member is provided in a region outside the intermediate portion between the rotating shaft and the outer peripheral surface of the rotor at the second end surface.   The compressor according to claim 5 or 6, wherein the second lift generating member is an airfoil.   The compressor according to any one of claims 5 to 7, wherein the second lift generating member and the second balance weight are the same member.

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