JPWO2015129184A1 - Hermetic compressor and refrigeration system - Google Patents

Abstract

The present invention provides a high-efficiency hermetic compressor that reduces the twist caused by the tilting of the piston during the intake stroke. A compression element of the compressor includes a shaft (110) having an eccentric shaft portion integrally interlocked with the main shaft portion, and a bearing portion (120) pivotally supporting the shaft, and a first center line indicating the shaft center of the bearing portion (141) and the angle a1 formed by the second center line (142) indicating the axis (D) of the cylinder (115) and the absolute value c1 of the angle of inclination of the shaft with respect to the bearing portion are expressed by the equation (1) And a seal portion (123a) that forms a sliding surface and an extension portion (123b) that forms a sliding surface located behind the seal portion and a sliding surface are formed on the outer peripheral surface of the piston (123). A non-sliding portion (123c) that does not. a1 = π / 2 + c1 (1)

Description

  The present invention relates to a hermetic compressor for reducing sliding loss of a piston, and a refrigeration apparatus equipped with the same.

  In recent years, a hermetic compressor used in a refrigeration apparatus such as a refrigerator has been desired to have higher efficiency in order to reduce power consumption.

  Under such circumstances, some of this type of hermetic compressors reduce sliding loss and improve efficiency by reducing the twist during the compression stroke of the piston reciprocating in the compression chamber. There are some (see, for example, Patent Document 1).

  Hereinafter, a conventional hermetic compressor will be described with reference to the drawings. FIG. 8 is a longitudinal sectional view of a conventional hermetic compressor. FIG. 9 is a cross-sectional view of a main part around a piston in a compression stroke of a conventional hermetic compressor. FIG. 10 is a cross-sectional view of a main part around a piston in a suction stroke of a conventional hermetic compressor.

  8 to 10, an electric element 304 having a stator 302 and a rotor 303 and a compression element 305 driven by the electric element 304 are contained in an airtight container 301 of a conventional hermetic compressor. Contained. The shaft 310 has a main shaft portion 311 and an eccentric shaft portion 312 formed eccentrically at one end thereof. A rotor 303 is fixed to the main shaft portion 311.

  The cylinder block 314 includes a substantially cylindrical cylinder 315 and a bearing portion 320. A piston 323 is reciprocally inserted in the cylinder 315, and a valve plate 350 is mounted on the end surface thereof. A compression chamber 316 is formed by the cylinder 315 and the piston 323.

  As shown in FIG. 9, a piston pin 325 is attached to the piston 323 so as to be parallel to the eccentric shaft portion 312. The bearing portion 320 forms a cantilever bearing by pivotally supporting the main shaft portion 311 of the shaft 310.

  The connecting rod 326 includes a large hole end portion 328, a small hole end portion 329, and a rod portion 330. The large hole end 328 is fitted to the eccentric shaft portion 312. The small hole end portion 329 is connected to the piston 323 via the piston pin 325. The eccentric shaft 312 and the piston 323 are connected by the connecting rod 326 and the piston pin 325.

  In the figure, the axis C indicates the axis of the piston 323, and the axis D indicates the axis of the cylinder 315.

  The operation of the conventional hermetic compressor configured as described above will be described below. When the electric element 304 is energized, the rotor 303 rotates the shaft 310. As the shaft 310 rotates, the rotational movement of the eccentric shaft portion 312 is transmitted to the piston 323 via the connecting rod 326. As a result, the piston 323 reciprocates in the cylinder 315. Reciprocating motion of the piston 323 causes refrigerant gas to be sucked into the compression chamber 316 from a cooling system (not shown) having a refrigeration cycle. The refrigerant gas is compressed in the compression chamber 316 and then discharged to the cooling system again.

  In the compression stroke of the reciprocating motion of the piston 323, the piston 323 is pushed toward the eccentric shaft portion 312 by the compression load that compresses the refrigerant gas, so that the shaft 310 is tilted in the bearing portion 320. As the shaft 310 is inclined, the axis C of the piston 323 is also inclined. For this reason, the axis C of the piston 323 and the axis D of the cylinder 315 are formed so that the axis D of the cylinder 315 is inclined so as to coincide with each other during the compression stroke. Thereby, the twist of the piston 323 in the cylinder 315 is reduced in the compression stroke, the sliding loss can be reduced, and high efficiency can be achieved.

  However, in the conventional hermetic compressor, as shown in FIG. 10, in the suction stroke of the reciprocating motion of the piston 323, the piston 323 is pulled toward the cylinder 315 by the suction load for sucking the refrigerant gas. Tilt to 315 side. Along with this, the axis C of the piston 323 is displaced from the axis D of the cylinder 315 formed by being tilted in advance. When the suction load increases particularly under severe operating conditions with a high compression ratio, the axis C of the piston 323 is further inclined so that the tip of the piston 323 is pressed against the bottom surface side of the compression chamber 316. For this reason, there is a problem that the piston 323 is twisted and the input increases.

Special table 2011-508840 gazette

  The present invention solves such a conventional problem, and provides a highly efficient hermetic compressor that reduces the twist caused by the tilting of the piston during the intake stroke and prevents an increase in input. is there.

  The hermetic compressor of the present invention is a hermetic compressor in which an electric element and a compression element driven by the electric element are accommodated in an airtight container. The compression element includes a main shaft portion, a shaft having an eccentric shaft portion that moves integrally with the main shaft portion, and a bearing portion that forms a cantilever bearing by pivotally supporting the main shaft portion of the shaft. The compression element includes a cylinder that compresses gas, a piston that is reciprocally inserted into the cylinder, and a connecting rod that connects the eccentric shaft portion and the piston. The angle a1 formed by the first center line indicating the axis of the bearing portion and the second center line indicating the axis of the cylinder and the absolute value c1 of the angle of inclination of the shaft with respect to the bearing portion are expressed by the equation Satisfy (1). In addition, the outer peripheral surface of the piston has a gap with the inner peripheral surface of the cylinder and forms a sliding portion, an extension portion that is located behind the sealing portion and forms the sliding surface, and a sealing portion And a non-sliding portion that does not form a sliding surface.

a1 = π / 2 + c1 (1)
Thus, even when the axial misalignment between the cylinder center and the piston axis becomes large during the intake stroke, a sliding surface is formed behind the seal portion that forms the piston sliding surface. There is a side extension. Thereby, it does not have the part used as a sliding surface in the vertical up-down direction. Therefore, local twisting in the vertical vertical direction when the piston is tilted can be reduced.

  The hermetic compressor of the present invention can reduce the local twisting in the intake stroke of the piston and prevent an increase in input, so that the efficiency can be improved.

FIG. 1 is a longitudinal sectional view of a hermetic compressor according to Embodiment 1 of the present invention. FIG. 2 is an enlarged cross-sectional view of a main part when a compression load acts during the compression stroke of the hermetic compressor according to Embodiment 1 of the present invention. FIG. 3 is an enlarged cross-sectional view of a main part when a suction load acts during the suction stroke of the hermetic compressor according to the first embodiment of the present invention. FIG. 4 is a top sectional view of the cylinder / piston of the hermetic compressor according to the first embodiment of the present invention. FIG. 5 is a longitudinal sectional view of the cylinder / piston of the hermetic compressor according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view of the main part showing the positional relationship between the bearing portion and the cylinder of the hermetic compressor according to Embodiment 1 of the present invention. FIG. 7 is a schematic cross-sectional view of the refrigerator in the second embodiment of the present invention. FIG. 8 is a longitudinal sectional view of a conventional hermetic compressor. FIG. 9 is a cross-sectional view of a main part around a piston in a compression stroke of a conventional hermetic compressor. FIG. 10 is a cross-sectional view of a main part around a piston in a suction stroke of a conventional hermetic compressor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to these 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 cross-sectional view of a main part when a compression load is applied during the compression stroke of the hermetic compressor. FIG. 3 is an enlarged cross-sectional view of a main part when a suction load acts during the suction stroke of the hermetic compressor. FIG. 4 is a top sectional view of the cylinder / piston of the hermetic compressor. FIG. 5 is a longitudinal sectional view of a cylinder / piston of the hermetic compressor. FIG. 6 is a cross-sectional view of the main part showing the positional relationship between the bearing portion and the cylinder of the hermetic compressor.

  1 to FIG. 6, an electric element 104 including a stator 102 and a rotor 103 and a compression element 105 driven by the electric element 104 are accommodated in a sealed container 101. Furthermore, lubricating oil 106 is stored at the bottom of the sealed container 101.

  The sealed container 101 is filled with a hydrocarbon-based R600a refrigerant 106, and a low-viscosity lubricating oil 102 of VG3 to VG10 is sealed at the bottom.

  The electric element 104 includes a rotor 103 and a stator 102, and is driven by an inverter (not shown) at a plurality of operation frequencies including at least an operation frequency equal to or higher than a power supply frequency. The maximum operating frequency for driving the electric element 104 is 80 Hz, and the electric element 104 is driven at an operating frequency of 17 Hz or more.

  The shaft 110 has a main shaft portion 111 and an eccentric shaft portion 112 formed eccentrically at one end of the main shaft portion 111 so as to move integrally with the main shaft portion 111. The rotor 103 is fixed to the main shaft portion 111. An oil supply passage 113 is provided inside and on the surface of the shaft 110. The lower portion of the oil supply passage 113 extends so as to be immersed in the lubricating oil 106 to a predetermined depth position of the lubricating oil 106.

  The cylinder block 114 includes a cylindrical cylinder 115 (including a substantially cylindrical shape) and a bearing portion 120. The bearing portion 120 forms a cantilever bearing by pivotally supporting the main shaft portion 111 of the shaft 110.

  A piston 123 is reciprocally inserted in the cylinder 115. A valve plate 150 is attached to the end of the cylinder 115. A compression chamber 116 is formed by the cylinder 115 and the piston 123.

  A piston pin 125 is attached to the piston 123 so as to be parallel to the eccentric shaft portion 112. As shown in FIGS. 4 and 5, a seal portion 123 a and an extension portion 123 b are provided on the outer peripheral surface of the piston 123. The seal portion 123 a forms a sliding surface in a cylindrical shape so as to have a small clearance with respect to the inner peripheral surface of the cylinder 115. The extension part 123b has the same radius as the seal part 123a on both side surfaces behind the seal part 123a, and forms a sliding surface extended with a constant width in the axial direction of the piston 123. On the vertical upper and lower surfaces behind the seal portion 123a, a non-sliding portion 123c that does not slide due to a larger clearance with respect to the inner peripheral surface of the cylinder 115 is provided.

  As shown in FIG. 2, the connecting rod 126 includes a large hole end portion 128, a small hole end portion 129, and a rod portion 130. The large hole end portion 128 is fitted to the eccentric shaft portion 112. The small hole end portion 129 is connected to the piston 123 via the piston pin 125. The eccentric shaft portion 112 and the piston 123 are connected by the connecting rod 126 and the piston pin 125.

  Here, generally, the shaft 110, the connecting rod 126, the piston pin 125, and the piston 123 that constitute a part of the compression element 105 are the axis 144 of the main shaft portion 111 of the shaft 110 and the axis of the piston 123 that reciprocates. The center C is assembled at an angle π / 2 (rad). This is because the driving loss is smoothest during driving and the driving loss is reduced. The configuration of the present embodiment is also like that.

  The dimensions of the piston 123 in this embodiment are a diameter of 26 mm and a total length of 23 mm, and the axial lengths of the seal portion 123a and the extension portion 123b are 8 mm and 15 mm, respectively. Further, the radial clearance between the inner peripheral surface of the cylinder 115 and the seal portion 123a and the extension portion 123b which are sliding surfaces is 0.005 mm. The radial clearance between the inner peripheral surface of the cylinder 115 and the non-sliding portion 123c is 0.5 mm.

  On the other hand, as shown in FIG. 6, a projection plane parallel to the first center line 141 indicating the axis of the bearing 120 and parallel to the second center line 142 indicating the axis of the cylinder 115 will be considered. An angle formed by the first center line 141 and the second center line 142 is a1. The absolute value of the inclination angle of the shaft 110 with respect to the bearing portion 120 due to the diameter clearance between the bearing portion 120 and the main shaft portion 111 is defined as c1 (rad). The cylinder block 114 (cylinder 115) is configured such that a1 and c1 satisfy the formula (1).

a1 = π / 2 + c1 (1)
The operation of the hermetic compressor configured as described above will be described below. When the electric element 104 is energized, the rotor 103 rotates the shaft 110. The rotational movement of the eccentric shaft portion 112 accompanying the rotation of the shaft 110 is transmitted to the piston 123 via the connecting rod 126.

  Thereby, the piston 123 reciprocates in the cylinder 115. The reciprocating motion of the piston 123 causes the refrigerant gas to be sucked into the compression chamber 116 from a cooling system (not shown) having a refrigeration cycle. The refrigerant gas is compressed in the compression chamber 116 and then discharged to the cooling system again.

  At the lower end of the oil supply passage 113, a pump action is caused by the rotation of the shaft 110. The lubricating oil 106 at the bottom of the sealed container 101 is pumped upward through the oil supply passage 113 and scatters horizontally in the entire circumferential direction in the sealed container 101. The scattered lubricating oil 106 is supplied to the piston pin 125, the piston 123, etc., and lubricates the piston pin 125, the piston 123, etc.

  Next, a description will be given of the twisting of the piston.

  Generally, in a hermetic compressor having a cantilever bearing structure, a compression load when compressing refrigerant gas is supported only on one side of the main shaft portion 111 of the shaft 110. Therefore, when a compressive load is applied during the compression stroke, the shaft 110 is inclined within the diameter clearance between the main shaft portion 111 and the bearing portion 120 as shown in FIG. Therefore, since the angle of the axis C of the piston 123 with respect to the axis 144 of the main shaft 111 is set to π / 2 (rad), the valve plate 150 side of the piston 123 is lifted above the horizontal line. Tilt.

  In the present embodiment, in consideration of the inclination of the piston 123, the valve plate 150 side of the axis D of the cylinder 115 is previously inclined so as to be lifted upward from the horizontal line.

  Therefore, when a compression load is applied to the piston 123 during the compression stroke, the axis D of the cylinder 115 and the axis C of the piston 123 coincide as shown in FIG. Thereby, the twist of the piston 123 which reciprocates is reduced.

  In FIG. 6, the intersection of the first center line 141 indicating the axis of the bearing 120 and the second center line 142 indicating the axis of the cylinder 115 is defined as O. The absolute value of the angle of inclination of the shaft 110 with respect to the bearing portion 120 based on the diameter clearance between the bearing portion 120 and the main shaft portion 111 is defined as c1. At this time, the cylinder 115 is moved so that the angle a1 between the first center line 141 indicating the axis of the bearing portion 120 and the second center line 142 indicating the axis of the cylinder 115 satisfies the expression (1). Forming.

  That is, in the present embodiment, the angle a1 represented by the equation (1) is set as the design value of the angle of the axis of the cylinder 115. The angle a1 is designed to approach an actual value using the absolute value c1 of the angle of inclination of the shaft 110 with respect to the bearing portion 120. Therefore, the twist between the piston 123 and the cylinder 115 can be more reliably reduced.

  On the other hand, when a suction force acts on the piston 123 during the suction stroke, the shaft 110 is tilted within a diameter clearance between the main shaft portion 111 and the bearing portion 120 as shown in FIG. Therefore, since the angle of the axis C of the piston 123 with respect to the axis 144 of the main shaft 111 of the shaft 110 inclined within the diameter clearance of the bearing 120 is assembled to be π / 2 (rad). The valve plate 150 side of the piston 123 is inclined in a direction facing downward from the horizontal line. Accordingly, a deviation occurs with respect to the axis D of the cylinder 115 set in consideration of the inclination of the piston 123 during the compression stroke.

  Thus, in the suction stroke, a suction load acts on the piston 123, and the axis C of the piston 123 is inclined with respect to the axis D of the cylinder 115 so as to be displaced downward. At this time, as shown in FIG. 5, the maximum amount of radial inclination of the seal portion 123a due to the axial deviation angle α of the piston 123 is represented by the axial length L × sin (α) of the seal portion 123a. .

  Generally, the piston 123 of the hermetic compressor used for the same application as that of the present embodiment is formed with the entire axial length of the piston 123 as a seal portion 123a in order to ensure sealing performance and sliding reliability. Is done. Further, the radial clearance of the seal portion 123a is the smallest among the constituent elements of the compression element 105, and is 0.005 mm in the present embodiment. Therefore, the maximum amount of radial inclination of the seal portion 123a during the suction stroke is greater than the radial clearance 0.005 mm of the seal portion 123a. For this reason, the E portion on the compression chamber 116 side of the piston 123 and the F portion on the eccentric shaft portion 112 side are twisted.

  However, in the present embodiment, the sliding portion of the piston 123 is constituted by the seal portion 123a and the extension portions 123b on both side surfaces that support the side pressure. Thereby, F part is non-sliding part 123c whose radius clearance is 0.5 mm, and is sufficiently larger than the radial clearance 0.005 mm of the seal part. For this reason, the piston 123 does not come into contact with the inner peripheral surface of the cylinder 115 at the F portion.

  Further, even in the vicinity of the E portion, the maximum radial amount L × Sin (α) of the seal portion 123a in the radial direction due to the shaft misalignment angle α is smaller than the radial clearance 0.005 mm because the length L of the seal portion 123a is small. .

  Therefore, even when a suction load is applied during the suction stroke, it is possible to suppress the occurrence of twisting of the E portion of the piston 123.

  That is, it is possible to suppress the twisting between the piston 123 and the cylinder 115 in the compression stroke, and to suppress the twisting between the piston 123 and the cylinder 115 in the suction stroke.

  Moreover, since the suction force during the suction stroke is significantly smaller than the compression load, the inclination angle of the piston 123 is smaller during the suction stroke than during the compression stroke. Further, since the piston 123 and the cylinder 115 are smaller in the suction stroke than in the compression stroke, the twist between the piston 123 and the cylinder 115 in the suction stroke is effectively reduced.

  As described above, according to the present embodiment, the sliding loss between the piston 123 and the cylinder 115 can be reduced and the efficiency can be improved during both the compression and suction strokes.

  As described above, the hermetic compressor of the present embodiment is a hermetic compressor in which the electric element 104 and the compression element 105 driven by the electric element 104 are accommodated in the hermetic container 101. The compression element 105 includes a main shaft 111, a shaft 110 having an eccentric shaft 112 that moves integrally with the main shaft 111, and a bearing 120 that forms a cantilever bearing by supporting the main shaft 111 of the shaft 110. With. The compression element 105 includes a cylinder 115 that compresses gas, a piston 123 that is reciprocally inserted into the cylinder 115, and a connecting rod 126 that connects the eccentric shaft portion 112 and the piston 123. Also, the absolute angle of the angle a1 formed by the first center line 141 indicating the axis of the bearing portion 120 and the second center line 142 indicating the axis of the cylinder 115 and the inclination angle of the shaft 110 with respect to the bearing portion 120 are absolute. The value c1 satisfies the formula (1). In addition, the outer peripheral surface of the piston 123 has a gap with the inner peripheral surface of the cylinder 115, and forms a sliding surface, a seal portion 123a, and an extension portion that is located behind the sealing portion 123a and forms a sliding surface. 123b and the non-sliding part 123c which is located behind the seal part 123a and does not form a sliding surface.

  Thereby, the sliding loss of the piston 123 and the cylinder 115 can be reduced during both the compression and suction strokes, and the efficiency can be increased.

  Further, the extension portion 123b has the same radius as the seal portion 123a and forms a sliding surface that supports the side pressure. As a result, local twisting of the piston can be reduced, an increase in input can be prevented, and high efficiency can be achieved.

  The electric element 104 is driven at a plurality of rotation speeds by an inverter circuit.

  As a result, the amount of oil supplied to the piston is reduced by low-speed rotation, and it is possible to prevent the piston from being twisted in the cylinder even under operating conditions where the oil film formed on the sliding surface of the piston is thin. Further, even in an intake stroke under an operating condition where the compression ratio is high and the piston is inclined at a high speed, the piston can be reduced in the cylinder, so that the efficiency can be improved.

(Embodiment 2)
FIG. 7 is a schematic cross-sectional view of the refrigerator in the second embodiment of the present invention. Here, a refrigerator will be described as an example of the refrigeration apparatus. The refrigerator in FIG. 7 is mounted with the hermetic compressor described in the first embodiment.

  In FIG. 7, the heat insulating box 180 includes an inner box 182, an outer box 184, and a heat insulating wall. The inner box 182 is formed by vacuum molding a resin body such as ABS (Acrylonitrile, Butadiene, Styrene). A metal material such as a pre-coated steel plate is used for the outer box 184. The heat insulating wall is formed by injecting a heat insulating body 186 to be foam-filled into a space formed by the inner box 182 and the outer box 184. For the heat insulator 186, for example, rigid urethane foam, phenol foam, styrene foam, or the like is used. As the foaming material, use of hydrocarbon-based cyclopentane is better from the viewpoint of preventing global warming.

  The heat insulation box 180 is divided into a plurality of heat insulation sections, and the upper part is configured as a rotary door type and the lower part as a drawer type. The plurality of heat insulation compartments are, from above, a refrigerator compartment 188, a drawer type switching room 190 and an ice making room 192, a drawer type vegetable room 194, and a drawer type freezing room 196 provided side by side. Each heat insulation section is provided with a heat insulation door via a gasket. From the top, the refrigerating room rotary door 198, the switching room drawer door 200, the ice making room drawer door 202, the vegetable room drawer door 204, and the freezer compartment drawer door 206.

  Moreover, the outer box 184 of the heat insulation box 180 is provided with the recessed part 208 which dented the top surface back.

  The refrigeration cycle includes a hermetic compressor 210, a condenser (not shown) provided on the side of the heat insulating box 180, a capillary 212 as a decompressor, a dryer (not shown) for removing moisture, and evaporation. The vessel 216 and the suction pipe 218 are connected in a ring shape. The hermetic compressor 210 is the hermetic compressor described in the first embodiment, and is elastically supported by the recess 208. The evaporator 216 is provided with a cooling fan 214 in the vicinity on the back of the vegetable compartment 194 and the freezer compartment 196.

  About the refrigerator comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, the temperature setting and cooling method of each heat insulation section will be described.

  The temperature of the refrigerator compartment 188 is normally set at 1 to 5 ° C., with the lower limit being the temperature at which it does not freeze for refrigerated storage.

  The temperature of the switching chamber 190 can be changed by the user, and the setting can be changed within a predetermined temperature range from the freezer temperature range to the refrigeration / vegetable temperature range.

  The ice making room 192 is an independent ice storage room. The ice making chamber 192 includes an automatic ice making device (not shown), and automatically creates and stores ice. The temperature of the ice making chamber 192 is a freezing temperature zone for storing ice, but may be set at a freezing temperature of −18 ° C. to −10 ° C. that is relatively higher than the freezing temperature zone for storing ice. Is possible.

  The temperature of the vegetable compartment 194 is often set to 2 ° C. to 7 ° C., which is the same as or slightly higher than that of the refrigerator compartment 188. It is possible to maintain the freshness of leafy vegetables for a long period of time as the temperature is lowered so as not to freeze.

  The temperature of the freezer compartment 196 is normally set at −22 to −18 ° C. for frozen storage. However, in order to improve the frozen storage state, it may be set at a low temperature of, for example, −30 to −25 ° C.

  Each chamber is partitioned by an insulating wall to efficiently maintain different temperature settings. However, as a method of improving the heat insulation performance at a low cost, it is possible to foam-fill the heat insulation box 180 integrally with the heat insulator 186. By performing foam filling with the heat insulator 186, it is possible to achieve a heat insulation performance that is approximately twice that of using a heat insulating member such as polystyrene foam, and the storage volume can be increased by thinning the partition.

  Next, the operation of the refrigeration cycle will be described.

  The cooling operation is started and stopped by a signal from a temperature sensor (not shown) and a control board in accordance with the set temperature in the refrigerator. The hermetic compressor 210 performs a predetermined compression operation according to the instruction of the cooling operation. The discharged high-temperature and high-pressure refrigerant gas dissipates heat in a condenser (not shown) to be condensed and liquefied, and is depressurized by the capillary 212 to become a low-temperature and low-pressure liquid refrigerant and reaches the evaporator 216.

  By the operation of the cooling fan 214, heat is exchanged with the air in the refrigerator, the refrigerant gas in the evaporator 216 is evaporated, and the low-temperature cold air that has been heat-exchanged is distributed by a damper (not shown), etc. The chamber is cooled.

  In the hermetic compressor 210 of the refrigerator that performs the above operation, as described in the first embodiment, the cylinder block 114 includes the first center line 141 indicating the axis of the bearing 120 and the cylinder 115. The bearing portion 120 and the cylinder 115 are arranged so that the second center line 142 indicating the axial center of the shaft intersects each other. The absolute value c1 of the angle between the angle a1 (rad) formed by the first center line 141 and the second center line 142 and the inclination of the shaft 110 with respect to the bearing portion 120 due to the diameter clearance between the bearing portion 120 and the main shaft portion 111 ( rad) satisfies the formula (1). The piston 123 has a cylindrical seal portion 123a that has a uniform gap with the inner peripheral surface of the cylinder 115 on the outer peripheral surface and forms a sliding surface. Furthermore, the piston 123 has an extension part 123b that is located behind the seal part 123a, has the same radius as the seal part 123a, and forms a sliding surface that supports the side pressure.

  As a result, even when the axial misalignment between the axial center of the cylinder 115 and the axial center of the piston 123 increases during the intake stroke, the sliding area when the piston 123 tilts becomes small. This is because the piston 123 has only an extension portion 123b that forms a sliding surface that supports the lateral pressure behind the cylindrical seal portion 123a that forms the sliding surface of the piston 123, and the sliding surface in the vertical vertical direction. It is because it does not have.

  As a result, local twisting of the piston 123 is reduced, sliding loss can be reduced, and the efficiency of the hermetic compressor 210 can be improved. Therefore, the power consumption of the refrigerator can be reduced.

  As described above, the refrigerator according to the present embodiment is a refrigeration apparatus that uses the hermetic compressor according to the first embodiment in a refrigeration cycle. Thereby, the power consumption of a freezing apparatus can be reduced.

  As described above, the hermetic compressor according to the present invention can improve the efficiency by reducing the sliding loss of the piston, and is not limited to an electric refrigerator-freezer for home use, but also an air conditioner, a vending machine, and others. It can be applied to refrigeration equipment.

DESCRIPTION OF SYMBOLS 101 Sealed container 102 Stator 103 Rotor 104 Electric element 105 Compression element 106 Lubricating oil 110 Shaft 111 Main shaft part 112 Eccentric shaft part 113 Oil supply passage 114 Cylinder block 115 Cylinder 116 Compression chamber 120 Bearing part 123 Piston 123a Seal part 123b Extension part 123c Non-sliding portion 125 Piston pin 126 Connecting rod 128 Large hole end portion 129 Small hole end portion 130 Rod portion 141 First center line 142 Second center line 144 Shaft center 150 Valve plate 180 Heat insulation box 182 Inner box 184 Outer box 186 Heat insulator 188 Refrigeration room 190 Switching room 192 Ice making room 194 Vegetable room 196 Freezing room 198 Refrigeration room rotating door 200 Switching room drawer door 202 Ice making room drawer door 204 Vegetable room drawer door 206 Freezer compartment drawer door 208 Recessed part 10 hermetic compressor 212 capillary 214 cooling fan 216 evaporator 218 suction pipe

Claims (4)

A hermetic compressor in which an electric element and a compression element driven by the electric element are accommodated in an airtight container,
The compression element is
A shaft having a main shaft portion and an eccentric shaft portion that moves integrally with the main shaft portion;
A bearing portion that forms a cantilever bearing by pivotally supporting the main shaft portion of the shaft;
A cylinder for compressing the gas;
A piston inserted reciprocally in the cylinder;
A connecting rod for connecting the eccentric shaft portion and the piston;
An angle a1 formed by a first center line indicating the axis of the bearing portion and a second center line indicating the axis of the cylinder;
The absolute value c1 of the inclination angle of the shaft with respect to the bearing portion satisfies the formula (1),
On the outer peripheral surface of the piston,
A seal portion having a gap with the inner peripheral surface of the cylinder and forming a sliding surface;
An extension that is located behind the seal and forms a sliding surface;
A hermetic compressor including a non-sliding portion that is located behind the seal portion and does not form a sliding surface.
a1 = π / 2 + c1 (1) The hermetic compressor according to claim 1, wherein the extension portion has the same radius as the seal portion and forms the sliding surface that supports a side pressure. The hermetic compressor according to claim 1, wherein the electric element is driven at a plurality of rotation speeds by an inverter circuit. A refrigeration apparatus using the hermetic compressor according to any one of claims 1 to 3 in a refrigeration cycle.

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