JP2008038690A - Refrigerant compressor - Google Patents

Abstract

An object of the present invention is to provide a refrigerant compressor with low vibration by reducing the mass of a piston.
In a hollow portion 161 of a cylindrical piston 126 reciprocating in a compression chamber 123, a rib 163 protruding toward the axial center of the piston 126 is provided in the vicinity of a pin hole 162, and the piston 126 of the rib 163 is provided. By making the width seen from the axial center direction smaller than the diameter of the piston pin 142, the mass of the piston 126 can be reduced, and the reciprocating inertia force generated by the piston 126 reciprocating in the cylinder 124 can be reduced. Since it can be made small, an unbalanced force can be reduced and a refrigerant compressor with low vibration can be provided.
[Selection] Figure 2

Description

  The present invention relates to a refrigerant compressor used in a refrigeration cycle apparatus such as a refrigerator, a vending machine, or an air conditioner.

  Conventional refrigerant compressors generally have a balance weight attached to a rotor in order to reduce vibration (see, for example, Patent Document 1).

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

  FIG. 6 is a cross-sectional view of a conventional refrigerant compressor described in Patent Document 1. FIG. 7 is a perspective view of a conventional piston described in Patent Document 1. FIG. FIG. 8 is a perspective sectional view of a conventional piston described in Patent Document 1. As shown in FIG.

  6, 7, and 8, oil 2 is stored at the bottom of the sealed container 1, and a refrigerant R <b> 134 a (not shown) is sealed, and the electric element 3 and the compression driven by the electric element 3 are performed. The element 4 is elastically held by a plurality of springs 5.

  The compression element 4 includes a block 8 that forms a cylinder 6 and a bearing portion 7, a piston 9 that is reciprocally fitted in the cylinder 6, a main shaft portion 11 that is supported by the bearing portion 7 and that has a spiral groove 10 on the outer periphery. A crankshaft 13 formed of an eccentric portion 12 formed therebelow, a substantially cylindrical piston pin 15 fixed to the pin hole 14 of the piston 9, a large end portion 16 and a piston fitted into the eccentric portion 12. A connecting means 18 having a small end portion 17 to be fitted into the pin 15 and connecting the eccentric portion 12 and the piston pin 15 and an oil supply pipe 19 disposed at the lower end of the eccentric portion 12 are provided.

  The piston 9 accommodates the small end portion 17 of the connecting means 18 and has a hollow portion 20 in which a piston pin 15 that is inserted into the pin hole 14 and is inserted into the small end portion 17 is disposed.

  The electric element 3 includes a stator 31 fixed above the block 8 and provided with a winding 30, and a rotor 32 fixed to the main shaft portion 11 of the crankshaft 13 by shrink fitting or the like. The balance weight 33 is arrange | positioned by laminating | stacking an iron plate.

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

  When the electric element 3 is energized, the rotor 32 rotates, the rotor 32 rotationally drives the crankshaft 13, and the rotational movement of the eccentric portion 12 drives the piston 9 via the connecting means 18. Is reciprocated in the cylinder 6 so that the refrigerant R134a (not shown) is continuously compressed.

When this compression operation is performed, the piston 9 reciprocates, thereby generating a reciprocating inertia force that is an unbalanced force. Further, centrifugal force is also generated by the eccentric movement of the eccentric portion 12. The reciprocating inertial force and centrifugal force are balanced by providing a balance weight 33 so that the piston 9 and the eccentric portion 12 are in opposite phases, and the reciprocating inertial force of the piston 9 and the centrifugal force of the eccentric portion 12 are balanced. The vibration is reduced by canceling the force with the inertial force of the balance weight 33.
JP-A-8-270562

  However, in the above conventional configuration, the balance weight 33 that rotates the reciprocating motion of the piston 9 cannot be completely balanced, and an unbalanced force is generated. In order to reduce this unbalanced force, the piston 9 must be lightened. However, if the hollow portion 20 is enlarged to reduce the mass of the piston 9, the piston pin 15 cannot be supported by the pin hole 14 alone against the compression load. .

  The present invention solves the above-described conventional problems, and an object thereof is to provide a refrigerant compressor having low vibration.

  In order to solve the above-described conventional problems, the refrigerant compressor according to the present invention is provided with a rib protruding toward the axial center of the piston in the hollow portion of the piston in the vicinity of the pin hole, and the axial direction of the piston of the rib By making the width viewed from the side smaller than the diameter of the piston pin, the mass of the piston can be reduced, and the reciprocating inertia force generated by the piston can be reduced.

  Since the refrigerant compressor of the present invention can reduce the reciprocating inertia force, a refrigerant compressor with low vibration can be provided.

  The invention according to claim 1 is a crankshaft having a main shaft portion and an eccentric portion, a cylinder forming a compression chamber, and a cylindrical piston having a hollow portion on the side opposite to the compression chamber by reciprocating in the compression chamber. And a compression element having a substantially cylindrical piston pin fitted in a pin hole provided in the piston and disposed in the hollow portion, and a connecting means for connecting the eccentric portion and the piston pin. In the hollow portion, a rib protruding toward the axial center of the piston is provided in the vicinity of the pin hole, and the width of the rib viewed from the axial direction of the piston is smaller than the diameter of the piston pin. Thus, the mass of the piston can be reduced, and the reciprocating inertia force generated by the piston can be reduced, so that the vibration of the refrigerant compressor can be reduced.

  The invention according to claim 2 is the invention according to claim 1, wherein the compression element and the electric element that is disposed above the compression element and drives the compression element are elastically housed in a sealed container. Even if the compression element having the piston and the eccentric portion, which is a vibration source, is elastically held by a plurality of springs, the mass of the piston can be reduced and the reciprocating inertia force generated by the piston can be reduced. Therefore, the vibration of the refrigerant compressor can be reduced.

  The invention according to claim 3 uses a hydrocarbon refrigerant in the invention according to claim 1 or 2, and when the refrigerant is a hydrocarbon refrigerant, the outer diameter of the piston becomes large. Since the reciprocating inertia force generated by the piston can be reduced, the vibration of the refrigerant compressor can be reduced.

  In the invention according to claim 4, in the invention according to claim 1 or 2, since the rib can be integrally formed by forming the piston from a sintered material, the refrigerant compressor can be made inexpensive.

  The invention according to claim 5 is the reciprocation generated by the piston at the time of low rotation when using an electric motor driven by an inverter at a plurality of operating frequencies in the invention according to any one of claims 1 to 3. The dynamic inertia force can be reduced because the mass of the piston can be reduced, and the vibration of the refrigerant compressor can be reduced.

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

(Embodiment 1)
1 is a cross-sectional view of a refrigerant compressor according to Embodiment 1 of the present invention, FIG. 2 is a perspective view from the direction of the anti-compression chamber of the piston according to the embodiment, and FIG. 3 is the anti-compression chamber of the piston according to the embodiment. 4 is a perspective cross-sectional view from the direction of the compression chamber of the piston in the same embodiment, and FIG. 5 is an exploded perspective view of the main components in the same embodiment.

  In FIGS. 1 to 5, an electric element 102 and a compression element 103 constructed below the electric element 102 and driven by the electric element 102 are stored in the sealed container 101, and oil 104 is stored at the bottom, R600a (not shown) is enclosed as a refrigerant. Further, the electric element 102 and the compression element 103 are elastically held by supporting the block 105 constituting the compression element 103 by the upper ends of a plurality of springs 106 fixed to the lower part of the hermetic container 101.

  The electric element 102 includes a stator 112 having a winding 111 and a rotor 114 having a magnet 113 disposed therein, and an inverter circuit (not shown) has an operating frequency lower than the commercial power supply frequency. It is driven at a plurality of operating frequencies. The rotor 114 has a balance weight 115 formed by stacking iron plates, and is fixed to the main shaft portion 122 of the crankshaft 121 by shrink fitting or the like.

  The compression element 103 includes a block 105 including a cylinder 124 and a bearing portion 125 forming a compression chamber 123, a piston 126 reciprocally fitted in the cylinder 124, and a spindle 125 having a spiral groove 127 on the outer periphery thereof. The crankshaft 121 comprising the part 122 and the eccentric part 128 formed therebelow, the connecting part 129 for connecting the eccentric part 128 and the piston 126, and the oil supply pipe 131 arranged at the eccentric part lower end 130 are provided. .

  The connecting means 129 includes a large end portion 141 fitted to the eccentric portion 128, a small end portion 143 fitted to the piston pin 142, and a connecting portion 144 connecting the large end portion 141 and the small end portion 143. Have.

  The piston 126 has a hollow portion 161 formed on the anti-compression chamber side 160 and a pin hole 162 provided in a direction perpendicular to the reciprocating direction. In the present embodiment, the piston 126 is made of an iron-based sintered material. It is formed by a mold.

  The hollow portion 161 is formed with a pair of ribs 163 projecting toward the axial center of the piston 126 in the vicinity of the pin hole 162. The rib 163 includes a compression chamber side rib 164 and an anti-compression chamber side rib 165 with the pin hole 162 interposed therebetween, and the compression chamber side rib surface 171 and the anti-compression chamber side rib that are flush with the pin hole inner diameter surface 170 of the pin hole 162. A surface 172 is provided.

  The rib 163 has a width D as viewed from the axial direction of the piston 126 smaller than the diameter C of the piston pin 142. Specifically, D is about 0.5 times as large as C. Yes.

  The substantially cylindrical piston pin 142 is fitted and fixed in the pin hole 162 so as to contact the pin hole inner diameter surface 170, the compression chamber side rib surface 171, and the anti-compression chamber side rib surface 172. The portion 143 is fitted to the piston pin 142 at the hollow portion 161.

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

  When the electric element 102 is energized from the inverter circuit, the rotor 114 rotates at an arbitrary rotational speed. The rotor 114 rotates the crankshaft 121, and the eccentric motion of the eccentric portion 128 is transmitted to the piston 126 via the connecting means 129 and the piston pin 142, whereby the piston 126 reciprocates in the cylinder 124, and the refrigerant R600a (Not shown) is continuously compressed.

  At this time, the force of the reciprocating motion of the piston 126 is balanced by the force of the balance weight 115 that rotates, but the force of the reciprocating motion of the piston 126 cannot be completely canceled and an unbalanced force is generated. . However, in the present embodiment, the hollow portion 161 of the piston 126 is formed by forming the rib 163 in the hollow portion 161 of the piston 126 so that the width D viewed from the axial direction of the piston 126 is smaller than the diameter C of the piston pin 142. The space volume of 161 can be made extremely large, and the mass of the piston 126 can be significantly reduced relatively. As a result, the unbalanced force can be greatly reduced, and the vibration of the refrigerant compressor can be greatly reduced.

  On the other hand, the inertial force due to the reciprocating motion of the piston 126 and the compressive force applied to the piston 126 when the piston 126 compresses the refrigerant gas are transmitted to the pin hole 162 via the piston pin 142. In the present embodiment, the piston pin 142 is fitted and fixed in the pin hole 162 so as to contact the pin hole inner diameter surface 170, the compression chamber side rib surface 171 and the anti-compression chamber side rib surface 172. The load applied to 142 can be received with a low surface pressure, and the load resistance of the piston pin 142 can be sufficiently ensured.

  Further, in the present embodiment, the refrigerant R600a having a small refrigerating capacity per suction volume compared to the refrigerant such as R134a is used, but the refrigerant R600a has a small refrigerating capacity per compressor suction volume compared to the R134a refrigerant. Therefore, in order to obtain the same refrigeration capacity as that of the R134a refrigerant, it is necessary to increase the displacement by the piston 126 nearly twice as much as that of the R134a refrigerant. The amount of eccentricity with respect to 128 main shaft portions 122 is also increased by about 1.2 times.

  Therefore, since the mass of the piston 126 is originally large and the inertial force due to the reciprocating motion of the piston 126 is large, in the refrigerant compressor for the refrigerant R600a having a large unbalance force and high vibration, the mass of the piston 126 can be further reduced. The unbalanced force can be greatly reduced, and the vibration of the refrigerant compressor can be further reduced.

  In particular, during the low-speed operation of the inverter drive, the reciprocating motion of the piston 126 is delayed and the generation cycle of the reciprocating inertia force is increased, so that the unbalanced force that cannot be offset by the force of the balance weight 115 that rotates is increased. Therefore, the improvement effect of reducing vibration is further increased by reducing the mass of the piston 126 and reducing the unbalanced force.

  Further, even if the compression element 103 having the piston 126 and the eccentric portion 128 which is a vibration generation source is elastically held by the plurality of springs 106, the mass of the piston 126 can be reduced and generated by the reciprocating motion of the piston 126. Since the inertial force to be reduced can be reduced, the unbalanced force can be reduced and the vibration transmitted to the sealed container 101 is also low.

  Since the piston 126 is formed of a sintered material and can be molded by a molding die, the rib 163 can be integrally formed in the hollow portion 161 of the piston 126, and mass production is easy. Therefore, productivity is high and the piston 126 can be manufactured at low cost.

  As described above, since the refrigerant compressor according to the present invention can easily reduce vibration, it can also be used for a refrigerant compressor of an air conditioner or a vending machine in addition to a refrigerator.

Sectional drawing of the refrigerant compressor in Embodiment 1 of this invention. The perspective view from the anti-compression chamber direction of the piston in the same embodiment Perspective cross-sectional view from the direction of the anti-compression chamber of the piston in the same embodiment Perspective sectional view from the direction of the compression chamber of the piston in the same embodiment The exploded perspective view of the principal part component in the embodiment Sectional view of a conventional refrigerant compressor The perspective view from the anti-compression chamber direction of the piston in the conventional refrigerant compressor Cross-sectional perspective view of piston in anti-compression chamber direction in conventional refrigerant compressor

Explanation of symbols

DESCRIPTION OF SYMBOLS 103 Compression element 121 Crankshaft 122 Main shaft part 123 Compression chamber 124 Cylinder 126 Piston 128 Eccentric part 129 Connection means 142 Piston pin 161 Hollow part 162 Pin hole 163 Rib

Claims (5)

  A crankshaft having a main shaft portion and an eccentric portion, a cylinder that forms a compression chamber, a cylindrical piston that reciprocates in the compression chamber to form a hollow portion on the side opposite to the compression chamber, and a pin hole provided in the piston And a compression element having a substantially cylindrical piston pin fitted in the hollow portion, and a connecting means for connecting the eccentric portion and the piston pin. The piston is disposed in the hollow portion. The refrigerant compressor which provided the rib which protruded toward the shaft center in the vicinity of the said pin hole, and made the width | variety seen from the shaft center direction of the said piston smaller than the diameter of the said piston pin.   The refrigerant compressor according to claim 1, wherein a compression element and an electric element that is disposed above the compression element and drives the compression element are elastically housed in a sealed container.   The refrigerant compressor according to claim 1 or 2, wherein a hydrocarbon-based refrigerant is used.   The refrigerant compressor according to claim 1, wherein the piston is made of a sintered material.   The refrigerant compressor according to any one of claims 1 to 3, which is an inverter drive system.

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