JP5766165B2 - Rotary compressor - Google Patents

Description

  The present invention relates to a rotary compressor for compressing refrigerant gas used in a refrigeration cycle of a refrigerating and air-conditioning apparatus such as an air conditioner or a refrigerator.

  Conventionally, a piston slidably attached to the eccentric part of the crankshaft, a cylindrical cylinder chamber is formed, the cylinder in which the piston is arranged, a low pressure space and a high pressure space in the cylinder chamber There has been proposed a rotary compressor (rotary compressor) having vanes for partitioning. In such a rotary compressor, the space partitioned by the cylinder chamber inner circumferential surface, the piston outer circumferential surface and the vane becomes a compression chamber, and the piston is eccentrically rotated in the cylinder chamber to compress the refrigerant sucked into the cylinder chamber. To do. Such a conventional rotary compressor has also been proposed in which a piston is divided into a plurality of members.

  For example, in a conventional rotary compressor configured by dividing a piston into a plurality of members, it is assumed that the piston outer peripheral surface is prevented from being worn by sliding between the vane and the piston outer peripheral surface. The piston is composed of a double first roller 16a on the outside and a second roller 16b on the inside, and a hole 24 is provided in which the inner surface and the outer surface of the second roller 16b communicate with each other. " This has been proposed.

Japanese Patent Laid-Open No. 5-256282 (summary, FIGS. 1 and 2)

  In the rotary compressor described in Patent Document 1, an inner peripheral piston (described as the second roller 16b in Patent Document 1) that is slidably attached to the eccentric part is formed as a cylindrical one-piece. . And this inner peripheral side piston is attached to an eccentric part, after passing the main axis | shaft or subshaft of the crankshaft adjacent to the eccentric part through an inner peripheral side piston. For this reason, in the rotary compressor described in Patent Document 1, the outer peripheral surface of the eccentric portion on the side opposite to the eccentric side (the outer peripheral surface on the side opposite to the eccentric direction in the eccentric portion) is more than the outer peripheral surface of the main shaft or the sub shaft. It was necessary to have a protruding configuration. Alternatively, it is necessary to form the outer peripheral surface of the eccentric portion opposite to the eccentric side and the outer peripheral surface of the main shaft or the sub shaft in the same plane.

That is, as shown in FIG. 7A, the radius of the eccentric portion 4c is Re, and the eccentric amount of the eccentric portion 4c (the distance between the central axis of the main shaft 4a and the sub shaft 4b and the central axis of the eccentric portion 4c). ) Is e, the distance from the central axis of the main shaft 4a and the sub shaft 4b to the outer peripheral surface of the eccentric portion 4c on the side opposite to the eccentric side is Re-e. For this reason, in the rotary compressor described in Patent Document 1, when the inner peripheral side piston 50 is attached to the eccentric portion 4c from the main shaft 4a side, if the radius of the main shaft 4a is Rm, Re−e ≧ Rm. Thus, the crankshaft 4 had to be formed. Further, in the rotary compressor described in Patent Document 1, when the inner peripheral piston 50 is attached to the eccentric portion 4c from the sub shaft 4b side, assuming that the radius of the sub shaft 4b is Ra, Re-e ≧ Ra It was necessary to form the crankshaft 4 so as to be.
This is because, as shown in FIG. 7 (b), the outer peripheral surface of the eccentric portion 4c on the side opposite to the eccentric side is recessed from the outer peripheral surface of the main shaft 4a or the sub shaft 4b (that is, the inner periphery). Re-e <Rm when the side piston 50 is attached to the eccentric portion 4c from the main shaft 4a side, and Re-e <Ra when the inner peripheral side piston 50 is attached to the eccentric portion 4c from the sub shaft 4b side. When the inner peripheral side piston 50 is to be attached to the eccentric part 4c, the eccentric part 4c interferes with the inner peripheral side piston 50, and the inner peripheral side piston 50 is displaced from the eccentric part 4c. It is because it cannot be attached to.

On the other hand, if the displacement volume is increased to increase the capacity of the rotary compressor (high output), the eccentric amount of the piston (from the main shaft and the sub shaft of the crankshaft) is suppressed while suppressing the expansion of the outer diameter of the piston. It is necessary to increase the eccentricity). In other words, if the displacement volume is increased to increase the capacity of the rotary compressor, the eccentric amount of the eccentric portion (the deviation from the main shaft and the sub shaft of the crankshaft) is suppressed while suppressing the increase in the outer diameter of the eccentric portion. It is necessary to increase the core amount. When the eccentric amount of the eccentric portion is increased while suppressing the expansion of the outer diameter of the eccentric portion, the outer peripheral surface of the eccentric portion 4c on the side opposite to the eccentric side is the outer periphery of the main shaft 4a or the sub shaft 4b. It becomes a state of being recessed from the surface (that is, a state of Re-e <Rm or Re-e <Ra).
However, as described with reference to FIG. 7, the rotary compressor described in Patent Document 1 has a relationship between the outer peripheral surface of the eccentric portion on the side opposite to the eccentric side and the outer peripheral surface of the main shaft or the sub shaft. Or, unless Re−e ≧ Ra, the piston cannot be attached to the eccentric portion. For this reason, in the rotary compressor described in Patent Document 1, the outer diameter of the eccentric portion is such that the outer peripheral surface of the eccentric portion 4c on the side opposite to the eccentric side is recessed from the outer peripheral surface of the main shaft 4a or the sub shaft 4b. However, the amount of eccentricity of the eccentric portion cannot be increased while the expansion of the capacity of the rotary compressor is limited.

  Here, as a method of increasing the displacement volume of the rotary compressor, it is also conceivable to increase the heights of the piston and the cylinder while leaving the eccentric amounts of the eccentric portion and the piston as they are. However, between the outer peripheral surface on the eccentric side of the piston (the outer peripheral surface on the eccentric direction side of the eccentric portion) and the peripheral surface of the cylinder chamber is a seal portion that partitions the cylinder chamber into a low pressure space and a high pressure space. . For this reason, if the height of a piston and a cylinder is made high, the length of the said seal part will increase. Therefore, when attempting to increase the capacity of the rotary compressor by increasing the height of the piston and cylinder, the refrigerant gas on the high pressure space side leaks to the low pressure space side and the refrigerant gas sucked into the compression chamber (cylinder chamber) There has been a problem that the weight flow rate is lowered and the efficiency of the rotary compressor is significantly deteriorated.

  The present invention has been made in order to solve the above-described problems, and is capable of pushing the rotary compressor away while preventing the sealing performance between the high-pressure side space and the low-pressure side space in the cylinder chamber from being deteriorated. An object of the present invention is to provide a rotary compressor capable of increasing the volume.

The rotary compressor according to the present invention includes an electric motor having a stator and a rotor, a main shaft fixed to the rotor, a sub shaft provided on the opposite side of the main shaft in the axial direction, and the main shaft and the sub shaft. A crankshaft driven by the electric motor, a piston slidably attached to the eccentric portion, and a cylindrical cylinder chamber are formed. The cylinder in which the eccentric part and the piston are arranged, the compression mechanism part having a vane that partitions the cylinder chamber into a low pressure space and a high pressure space, the electric motor, the crankshaft, and the compression mechanism part are housed. A rotary container including a hermetic container, wherein the piston is provided on an outer peripheral surface of the eccentric portion and an outer peripheral surface of the inner peripheral piston. The outer peripheral piston Is, the inner peripheral side piston is constituted by a plurality of arcuate members, the radius of the minor axis Ra, the radius of the eccentric portion Re, the radius of the inner peripheral side piston Rp, and the When the eccentric amount of the eccentric portion is e, the relationship is Re-e <Ra <Rp-e .

In the rotary compressor according to the present invention, the piston includes an inner peripheral side piston slidably provided on the outer peripheral surface of the eccentric portion and an outer peripheral side piston provided on the outer peripheral surface of the inner peripheral side piston. It is configured. Further, the inner circumferential side piston is composed of a plurality of arcuate members. For this reason, the rotary compressor according to the present invention attaches each arc-shaped member, that is, the inner peripheral piston so that the eccentric portion is sandwiched between the plurality of arc-shaped members (from the direction perpendicular to the central axis of the eccentric portion). be able to. For this reason, even if the crankshaft has a configuration in which the outer peripheral surface of the eccentric portion on the side opposite to the eccentric side is recessed from the outer peripheral surface of the main shaft or the auxiliary shaft, the inner peripheral piston can be attached to the eccentric portion. . Therefore, the rotary compressor according to the present invention can increase the displacement volume without increasing the height of the piston and the cylinder.
That is, the rotary compressor according to the present invention can increase the displacement volume without causing a significant deterioration in efficiency caused by refrigerant leakage at the seal portion between the piston and the cylinder chamber peripheral surface. In other words, in the rotary compressor according to the present invention, when the displacement volume is not changed, the height of the piston and the cylinder can be made lower than that of the conventional rotary compressor, and the seal between the piston and the cylinder inner peripheral surface can be obtained. The refrigerant leakage in the section can be suppressed more than before.
Therefore, the present invention can provide a rotary compressor that can achieve higher output and higher efficiency than conventional ones.

It is a longitudinal section showing a rotary compressor concerning an embodiment of the invention. It is a cross-sectional view which shows the compression mechanism part of the rotary compressor which concerns on embodiment of this invention. It is explanatory drawing for demonstrating the inner peripheral side piston of the rotary compressor which concerns on embodiment of this invention, (a) is a longitudinal cross-sectional view which shows a crankshaft and an inner peripheral side piston, (b) is an inner peripheral side. It is a top view which shows a piston. It is a figure for demonstrating the piston attachment method to the eccentric part in the rotary compressor which concerns on embodiment of this invention, and is a perspective view which shows the state before attaching an inner peripheral side piston to the eccentric part of a crankshaft. is there. It is a figure for demonstrating the piston attachment method to the eccentric part in the rotary compressor which concerns on embodiment of this invention, and after this inner peripheral side piston is attached to the eccentric part of a crankshaft, this inner peripheral side It is a perspective view which shows the state before attaching an outer peripheral side piston to a piston. It is a figure for demonstrating the piston attachment method to the eccentric part in the rotary compressor which concerns on embodiment of this invention, After an inner peripheral side piston is attached to the eccentric part of a crankshaft, it is further this inner periphery It is a figure which shows the state which attached the outer peripheral side piston to the side piston. It is detail drawing which shows the eccentric part vicinity of the conventional rotary compressor.

Embodiment.
FIG. 1 is a longitudinal sectional view showing a rotary compressor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a compression mechanism portion of the rotary compressor. FIG. 3 is an explanatory view for explaining the inner peripheral side piston of the rotary compressor, wherein (a) is a longitudinal sectional view showing the crankshaft and the inner peripheral side piston, and (b) is an inner peripheral side piston. FIG.
Hereinafter, the configuration of the rotary compressor according to the present embodiment will be described with reference to FIGS.

  The rotary compressor 100 stores an electric motor 2 including a stator 2 a and a rotor 2 b and a compression mechanism unit 3 driven by the electric motor 2 in a hermetic container 1. The rotational force of the electric motor 2 is transmitted to the compression mechanism unit 3 via the crankshaft 4. In the sealed container 1, lubricating oil (refrigeration machine oil) that is lubricated by the compression mechanism unit 3 is stored.

  The crankshaft 4 includes a main shaft 4a fixed to the rotor 2b of the electric motor 2, a sub shaft 4b provided on the opposite side of the main shaft 4a, and an eccentric portion 4c formed between the main shaft 4a and the sub shaft 4b. Have

  In this embodiment, the shape of the crankshaft 4 is formed as follows. That is, in the present embodiment, the displacement of the rotary compressor 100 is increased, so that the eccentric amount of the eccentric portion 4c (from the main shaft 4a and the sub shaft 4b is suppressed while suppressing the increase in the outer diameter of the eccentric portion 4c. The eccentric amount) is increased. For this reason, the crankshaft 4 has an outer peripheral surface (an outer peripheral surface opposite to the eccentric direction in the eccentric portion 4c) of the eccentric portion 4c that is recessed from the outer peripheral portions of the main shaft 4a and the auxiliary shaft 4b. It has a shape. In other words, when the radius of the eccentric portion 4c is Re and the eccentric amount of the eccentric portion 4c (the distance between the central axis of the main shaft 4a and the auxiliary shaft 4b and the central axis of the eccentric portion 4c) is e, the main shaft 4a The distance from the central axis of the sub shaft 4b to the outer peripheral surface of the eccentric portion 4c on the opposite eccentric side is Re-e. Therefore, if the radius of the main shaft 4a is Rm and the radius of the sub shaft 4b is Ra, the crankshaft 4 of the rotary compressor 100 satisfies Re-e <Rm and Re-e <Ra. .

  The crankshaft 4 configured in this manner is rotatably supported by the main bearing 5 and the auxiliary bearing 6. In detail, the main bearing 5 is provided in the upper part of the compression mechanism part 3, and supports the main axis | shaft 4a of the crankshaft 4 rotatably. Further, the auxiliary bearing 6 is provided at the lower part of the compression mechanism section 3 and rotatably supports the auxiliary shaft 4b of the crankshaft 4.

  The compression mechanism unit 3 includes a cylinder 7, a piston 20, a vane 9, and the like.

  The cylinder 7 is fixed to the inner peripheral portion of the sealed container 1 and has a cylindrical cylinder chamber at the center thereof. The cylinder chamber is provided with a piston 20 that is slidably fitted to the eccentric portion 4 c of the crankshaft 4. Further, both end surfaces in the axial direction of the cylinder chamber of the cylinder 7 are closed by the main bearing 5 and the auxiliary bearing 6. Further, the cylinder 7 is provided with a vane 9 that reciprocates according to the rotation of the eccentric portion 4c. That is, the space partitioned by the outer peripheral surface of the piston 20, the inner peripheral surface of the cylinder chamber, and the vane 9 is a compression chamber. The compression chamber (cylinder chamber) is partitioned by the vane 9 into a high pressure side space and a low pressure side.

Here, in the present embodiment, the piston 20 is configured as shown in FIGS.
That is, the piston 20 includes an inner peripheral piston 21 slidably provided on the outer peripheral surface of the eccentric portion 4c, and an outer peripheral piston 22 provided slidably on the outer peripheral surface of the inner peripheral piston 21, for example. It consists of and. Moreover, the inner peripheral side piston 21 is comprised by the some circular-arc-shaped member 21a divided | segmented by the cross section along the central axis of the eccentric part 4c. In the present embodiment, the inner circumferential side piston 21 is constituted by two arc-shaped members 21a.

  In the rotary compressor 100 configured as described above, the crankshaft 4 fitted in the rotor 2b rotates as the rotor 2b rotates. As a result, the piston 20 slidably attached to the eccentric portion 4 c of the crankshaft 4 performs an eccentric rotational movement in the cylinder chamber of the cylinder 7. As the piston 20 rotates eccentrically, the volume of the high-pressure side space of the cylinder 7 gradually decreases, and the refrigerant gas in the high-pressure side space is compressed. The compressed refrigerant gas is discharged into the sealed container 1 and then sent out from the discharge pipe 11 to the outside. An accumulator 12 is provided adjacent to the hermetic container 1, and the accumulator 12 communicates with the cylinder chamber of the cylinder 7 via the suction connecting pipe 10. That is, the refrigerant gas is sent to the cylinder chamber of the cylinder 7 through the accumulator 12 and the suction connecting pipe 10.

  Next, a method for attaching the piston 20 to the eccentric portion 4c of the crankshaft 4 will be described with reference to FIGS.

  FIG. 4 is a view for explaining a method of attaching a piston to an eccentric portion in the rotary compressor according to the embodiment of the present invention, and shows a state before the inner peripheral side piston is assembled to the eccentric portion of the crankshaft. It is a perspective view shown. FIG. 5 is a view for explaining a method of attaching the piston to the eccentric portion in this rotary compressor. After the inner peripheral piston is attached to the eccentric portion of the crankshaft, the outer peripheral piston It is a perspective view which shows the state before attaching a side piston. FIG. 6 is a view for explaining a method of attaching the piston to the eccentric part in the rotary compressor. After the inner peripheral side piston is attached to the eccentric part of the crankshaft, the inner peripheral side is further shown. It is a figure which shows the state which attached the outer peripheral side piston to the piston. More specifically, FIG. 6A is a longitudinal sectional view showing a state in which the outer peripheral side piston is assembled to the inner peripheral side piston. FIG.6 (b) is a perspective view which shows the state which assembled | attached the outer peripheral side piston to the inner peripheral side piston. FIG.6 (c) is a top view which shows the state which assembled | attached the outer peripheral side piston to the inner peripheral side piston. In addition, illustration of a crankshaft is abbreviate | omitted in FIG.6 (c).

  When attaching the piston 20 to the eccentric part 4c of the crankshaft 4, first, as shown in FIG. 4, the inner peripheral side piston 21 is attached to the eccentric part 4c. Specifically, the two arcuate members 21a (that is, the inner circumferential piston 21) are attached to the eccentric part 4c so that the eccentric part 4c is sandwiched between the two arcuate members 21a constituting the inner peripheral piston 21. In other words, the two arcuate members 21a constituting the inner peripheral side piston 21 are attached to the eccentric portion 4c from the direction perpendicular to the central axis of the eccentric portion 4c.

  As described above, the inner peripheral piston of the conventional rotary compressor is formed as a single body. For this reason, in the conventional rotary compressor, in order to attach the inner peripheral side piston to the eccentric part of the crankshaft, the outer peripheral surface of the eccentric part opposite to the eccentric side protrudes from the outer peripheral surface of the main shaft or the sub shaft. There was a need to configure. Alternatively, it is necessary to form the outer peripheral surface of the eccentric portion opposite to the eccentric side and the outer peripheral surface of the main shaft or the sub shaft in the same plane. In other words, in the conventional rotary compressor, the crankshaft 4 having the shape as in the present embodiment (the outer peripheral surface of the eccentric portion 4c on the side opposite to the eccentric side is recessed more than the outer peripheral portions of the main shaft 4a and the sub shaft 4b. The inner peripheral side piston could not be attached to the shape crankshaft). However, by configuring the inner circumferential side piston 21 with the two arc-shaped members 21a as in the present embodiment, the outer circumferential surface on the anti-eccentric side of the eccentric portion 4c is more than the outer circumferential portion of the main shaft 4a and the auxiliary shaft 4b. The inner circumferential side piston 21 can also be attached to the crankshaft 4 having a concave shape.

  After attaching the inner peripheral side piston 21 to the eccentric part 4c of the crankshaft 4 as shown in FIG. 4, the outer peripheral side piston 22 is attached to the outer peripheral surface of the inner peripheral side piston 21 as shown in FIGS. . Specifically, the main shaft 4a or the sub shaft 4b is passed through the outer peripheral side piston 22 formed as a substantially cylindrical one. Thereafter, the outer peripheral piston 22 is attached to the outer peripheral surface of the inner peripheral piston 21.

  In the present embodiment, as shown in FIG. 3, when the radius Rp of the inner peripheral piston 21 is used, Rp-e is larger than the radius Rm of the main shaft 4a. For this reason, in the state where the inner peripheral side piston 21 is attached to the eccentric portion 4c, the outer peripheral surface of the inner peripheral side piston 21 opposite to the eccentric side protrudes from the outer peripheral surface of the main shaft 4a. For this reason, the outer peripheral side piston 22 can be attached to the eccentric part 4c from the main shaft 4a side. Moreover, in this Embodiment, as shown in FIG. 3, when it is set as the radius Rp of the inner peripheral side piston 21, Rp-e becomes a larger value than the radius Ra of the subshaft 4b. For this reason, in the state where the inner peripheral side piston 21 is attached to the eccentric portion 4c, the outer peripheral surface of the inner peripheral side piston 21 on the side opposite to the eccentric side protrudes from the outer peripheral surface of the auxiliary shaft 4b. For this reason, the outer peripheral side piston 22 can also be attached to the eccentric part 4c from the subshaft 4b side.

As described above, the rotary compressor 100 configured as in the present embodiment can obtain the following effects.
That is, as described above, the inner peripheral side piston of the conventional rotary compressor is formed as a single body. For this reason, in the conventional rotary compressor, in order to attach the inner peripheral side piston to the eccentric part of the crankshaft, the outer peripheral surface of the eccentric part opposite to the eccentric side protrudes from the outer peripheral surface of the main shaft or the sub shaft. There was a need to configure. Alternatively, it is necessary to form the outer peripheral surface of the eccentric portion opposite to the eccentric side and the outer peripheral surface of the main shaft or the sub shaft in the same plane. For this reason, in the conventional rotary compressor, this configuration has been a restriction on expansion of the displacement volume. However, the rotary compressor according to the present embodiment does not have such a restriction, and the outer peripheral surface of the eccentric portion 4c on the opposite eccentric side is recessed from the outer peripheral portions of the main shaft 4a and the auxiliary shaft 4b. 4 can also be attached to the inner circumferential side piston 21. Therefore, the rotary compressor according to the present embodiment can expand the displacement volume without being restricted by the above-described restrictions (that is, high output can be achieved).

  Here, as a method of increasing the displacement volume of the rotary compressor, it is also conceivable to increase the heights of the piston and the cylinder while leaving the eccentric amounts of the eccentric portion and the piston as they are. However, between the outer peripheral surface on the eccentric side of the piston (the outer peripheral surface on the eccentric direction side of the eccentric portion) and the peripheral surface of the cylinder chamber is a seal portion that partitions the cylinder chamber into a low pressure space and a high pressure space. . For this reason, if the height of a piston and a cylinder is made high, the length of the said seal part will increase. Therefore, when attempting to increase the capacity of the rotary compressor by increasing the height of the piston and cylinder, the refrigerant gas on the high pressure space side leaks to the low pressure space side and the refrigerant gas sucked into the compression chamber (cylinder chamber) A weight flow rate will fall and it will cause the remarkable deterioration of the efficiency of a rotary compressor. However, the rotary compressor 100 according to the present embodiment can expand the displacement volume without increasing the height of the piston 20 and the cylinder 7 as described above. That is, the rotary compressor 100 according to the present embodiment can increase the displacement volume without causing a significant deterioration in efficiency caused by refrigerant leakage at the seal portion between the piston 20 and the cylinder chamber peripheral surface. .

  In other words, in order to improve the efficiency of the rotary compressor without changing the displacement volume, the height of the piston 20 and the cylinder 7 is lowered, and the low pressure space is formed from the high pressure space side in the seal portion formed between them. It is important to reduce the amount of refrigerant gas that leaks to the side. At this time, in order to reduce the height of the piston and the cylinder without changing the displacement volume, it is necessary to increase the eccentric amount of the eccentric portion of the crankshaft. However, the conventional rotary compressor has not been able to increase the eccentric amount of the eccentric portion so much due to the above-described restrictions. For this reason, the conventional rotary compressor has a slight efficiency improvement range. On the other hand, since the rotary compressor 100 according to the present embodiment is not restricted by the above-described restrictions, the eccentric amount of the eccentric portion 4c can be made larger than the conventional one. For this reason, the rotary compressor 100 according to the present embodiment can sufficiently improve the efficiency as compared with the related art.

  In order to improve the efficiency of the rotary compressor without changing the displacement volume, in order to reduce the sliding speed between the outer peripheral surface of the eccentric portion and the inner peripheral surface of the piston, the radius of the eccentric portion (in other words, Therefore, it is also important to reduce the diameter. However, the conventional rotary compressor cannot make the radius of the eccentric portion so small when attempting to increase the eccentric amount of the eccentric portion due to the above-described restrictions. This is because if the radius of the eccentric portion is reduced, the outer peripheral surface of the eccentric portion on the side opposite to the eccentric side is recessed from the outer peripheral surface of the main shaft or the sub shaft. For this reason, the conventional rotary compressor has a slight efficiency improvement width by reducing the radius of the eccentric portion. On the other hand, since the rotary compressor 100 according to the present embodiment is not restricted by the above-described restrictions, when the eccentric amount of the eccentric portion 4c is made equal to the conventional one, the radius of the eccentric portion 4c is set to be the same. It can be made smaller than before. For this reason, the rotary compressor 100 according to the present embodiment can further improve the efficiency.

  In the present embodiment, the example in which the inner peripheral piston 21 is divided into two arc-shaped members 21a has been described. However, the inner peripheral piston 21 may of course be divided into three or more arc-shaped members 21a. . By increasing the number of arc-shaped members 21a constituting the inner peripheral side piston 21, it is possible to reduce the size of the material used when manufacturing the inner peripheral side piston 21, so that the yield of the material is improved. Furthermore, the loading efficiency in the transportation of materials is improved. That is, by increasing the number of the arc-shaped members 21a constituting the inner peripheral side piston 21, it is possible to provide an effect that the highly efficient rotary compressor 100 can be provided while the manufacturing cost is low.

  In the present embodiment, the rotary compressor 100 having one compression mechanism unit 3 has been described. However, the rotary compressor 100 may be configured as a multi-cylinder rotary compressor having a plurality of compression mechanism units 3. In this case, a plurality of eccentric portions 4c are formed between the main shaft 4a and the sub shaft 4b, and these eccentric portions 4c are connected by an intermediate shaft. A plurality of cylinders 7 are provided corresponding to the eccentric portions 4 c, and the end surfaces of the cylinder chambers opened between the cylinders 7 are closed by partition plates provided between the cylinders 7. In the case where the rotary compressor 100 is configured as a multi-cylinder rotary compressor, it is preferable that each eccentric portion 4c is disposed on the axis with respect to the central axes of the main shaft 4a and the sub shaft 4b. For example, when the rotary compressor 100 is configured as a two-cylinder rotary compressor, the two eccentric portions 4c are preferably formed with a phase difference of 180 ° with respect to the central axes of the main shaft 4a and the sub shaft 4b. By forming each eccentric portion 4c in this way, vibrations and the like generated due to the rotation of the crankshaft 4 can be suppressed.

  In the present embodiment, “the clearance between the outer peripheral surface of the eccentric portion 4 c and the inner peripheral surface of the inner peripheral piston 21” and “the outer peripheral surface of the inner peripheral piston 21 and the inner periphery of the outer piston 22. Although no particular mention was made of the relationship with the “clearance between surfaces”, for example, both clearances may have substantially the same dimensions (hereinafter, “substantially the same”, that is, substantially the same, In other words, “same” shown in this embodiment does not mean that it is exactly the same). For example, “clearance between the outer peripheral surface of the eccentric portion 4 c and the inner peripheral surface of the inner peripheral piston 21” and “clearance between the outer peripheral surface of the inner peripheral piston 21 and the inner peripheral surface of the outer piston 22. "Is too different," the frictional force between the outer peripheral surface of the eccentric portion 4c and the inner peripheral surface of the inner piston 21 and "the outer peripheral surface of the inner piston 21 and the outer piston 22 The difference from the “frictional force with the inner peripheral surface” becomes large. For this reason, the rotational speeds of the inner circumferential piston 21 and the outer circumferential piston 22 are significantly different, and the sliding speed between the inner circumferential surface of the inner circumferential piston 21 and the inner circumferential surface of the outer circumferential piston 22 is increased. There is concern about causing abnormal wear. However, “the clearance between the outer peripheral surface of the eccentric portion 4 c and the inner peripheral surface of the inner peripheral side piston 21” and “the clearance between the outer peripheral surface of the inner peripheral side piston 21 and the inner peripheral surface of the outer peripheral side piston 22. ”In the same dimension, the sliding speed of the inner peripheral surface of the inner peripheral side piston 21 and the inner peripheral surface of the outer peripheral side piston 22 can be appropriately maintained, and abnormal wear in this portion can be prevented. Can do.

  Further, in the rotary compressor 100 according to the present embodiment, the inner peripheral side piston 21 is a divided part and the outer peripheral side piston 22 is an integrally molded part, and therefore, it is assumed that the rotary compressor 100 is formed of different materials. In such a case, it is preferable to select both materials so that the material of the inner circumferential piston 21 and the material of the outer circumferential piston 22 have the same linear expansion coefficient. When the rotary compressor 100 is operated, the inner peripheral side piston 21 and the outer peripheral side piston 22 are thermally expanded. At this time, if the linear expansion coefficients of the two are too different, the “clearance between the inner circumferential piston 21 and the main bearing 5 and the auxiliary bearing 6” and “between the outer circumferential piston 22 and the main bearing 5 and the auxiliary bearing 6”. The difference in “clearance” increases. For this reason, the difference between the “friction force between the inner peripheral piston 21 and the main bearing 5 and the sub bearing 6” and the “friction force between the outer piston 22 and the main bearing 5 and the sub bearing 6” is increased. . Accordingly, the rotational speeds of the inner peripheral piston 21 and the outer peripheral piston 22 are remarkably different, and the sliding speed between the inner peripheral surface of the inner peripheral piston 21 and the inner peripheral surface of the outer peripheral piston 22 is increased. There is concern about causing wear. However, by selecting both materials so that the material of the inner circumferential side piston 21 and the material of the outer circumferential side piston 22 have the same linear expansion coefficient, “the inner circumferential side piston 21, the main bearing 5, the auxiliary bearing 6, and And the “clearance between the outer peripheral piston 22 and the main bearing 5 and the sub-bearing 6” can be made the same. For this reason, the sliding speed of the inner peripheral surface of the inner peripheral side piston 21 and the inner peripheral surface of the outer peripheral side piston 22 can be appropriately maintained, and abnormal wear at this portion can be prevented.

  DESCRIPTION OF SYMBOLS 1 Airtight container, 2 Electric motor, 2a Stator, 2b Rotor, 3 Compression mechanism part, 4 Crankshaft, 4a Main shaft, 4b Subshaft, 4c Eccentric part, 5 Main bearing, 6 Sub bearing, 7 Cylinder, 9 Vane, DESCRIPTION OF SYMBOLS 10 suction | inhalation connection pipe, 11 discharge pipe, 12 accumulator, 20 piston, 21 inner peripheral side piston, 21a circular member, 22 outer peripheral side piston, 50 inner peripheral side piston (conventional), 100 rotary compressor.

Claims (6)

An electric motor having a stator and a rotor;
A main shaft fixed to the rotor, a sub shaft provided on the opposite side of the main shaft in the axial direction, and an eccentric portion formed between the main shaft and the sub shaft, and driven by the electric motor. Crankshaft
A piston slidably attached to the eccentric part, a cylindrical cylinder chamber is formed, a cylinder in which the eccentric part and the piston are arranged in the cylinder chamber, and a low pressure space and a high pressure in the cylinder chamber A compression mechanism having a vane that partitions into a space;
A sealed container that houses the electric motor, the crankshaft, and the compression mechanism;
A rotary compressor comprising:
The piston is composed of an inner peripheral side piston slidably provided on the outer peripheral surface of the eccentric part, and an outer peripheral side piston provided on the outer peripheral surface of the inner peripheral side piston,
The inner circumferential side piston is composed of a plurality of arcuate members ,
When the radius of the auxiliary shaft is Ra, the radius of the eccentric portion is Re, the radius of the inner peripheral side piston is Rp, and the eccentric amount of the eccentric portion is e,
Re-e <Ra <Rp-e
A rotary compressor characterized by having the following relationship:   2. The rotary compressor according to claim 1, wherein the inner peripheral side piston is configured by three or more arc-shaped members. When the radius of the main shaft is Rm, the radius of the eccentric part is Re, the radius of the inner peripheral side piston is Rp, and the eccentric amount of the eccentric part is e,
Re-e <Rm <Rp-e
The rotary compressor according to claim 1 or 2, wherein the relationship is as follows. The rotary compressor according to any one of claims 1 to 3 , wherein a plurality of the eccentric part and the compression mechanism part of the crankshaft are provided. A clearance formed between the outer peripheral surface of the eccentric portion and the inner peripheral surface of the inner peripheral piston, and a clearance formed between the outer peripheral surface of the inner peripheral piston and the outer peripheral piston. The rotary compressor according to any one of claims 1 to 4 , wherein the rotary compressor is the same. The rotary compressor according to any one of claims 1 to 5 , wherein a linear expansion coefficient of the outer peripheral piston and a linear expansion coefficient of the inner peripheral piston are the same.

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