[Name of Document]

DESCRIPTION

[Title of Invention]

ROTARY COMPRESSOR

[Technical Field]

[0001]
The present invention relates to a rotary compressor that compresses refrigerant gas and that is employed in a refrigeration cycle of a refrigeration and air-conditioning apparatus such as an air-conditioning device, a refrigerator, and the like.

Background Art

[0002]
In a 2-cylinder rotary compressor, which compresses low-pressure refrigerant gas into high-pressure refrigerant gas in each of two compression chambers, and in a 2-stage rotary compressor, which compresses low-pressure refrigerant gas into refrigerant gas with intermediate-pressure in a low-stage side compression chamber and which compresses intermediate-pressure refrigerant gas into high-pressure refrigerant gas in a high-stage side compression chamber, a crankshaft is provided with two eccentrics each disposed in corresponding one of cylinders and an intermediate shaft is provided between the eccentrics. Hitherto, there has been proposed a 2-cylinder rotary compressor and a 2-stage rotary compressor attempting to improve the rigidity of the intermediate shaft. As for such a 2-cylinder rotary compressor attempting to improve the rigidity of the intermediate shaft, for example, there is one in which the periphery of the intermediate shaft is formed along each periphery of two eccentrics on their counter-eccentric sides while the periphery of the intermediate shaft being formed on the shaft center side relative to the peripheries of the two eccentrics on their eccentric sides, in which the cross section of the intermediate shaft orthogonal to its shaft direction is of a substantially rugby ball shape (convex shaped in the direction orthogonal to the eccentric direction of the eccentric), has been proposed (see Patent Literature 1, for example).

[Citation List]

[Patent Literature]

[0003]
[Patent Literature 1] WO 2009/028633 (Figs. 2A and 2B) [Summary of Invention] [Technical Problem]

[0004]
A 2-cylinder rotary compressor and a 2-stage rotary compressor are provided with a partition plate between two compression chambers so as to partition each compression chamber that is correspondingly formed with an eccentric. Accordingly, the partition plate is formed with a cylindrical through hole in which an intermediate shaft is disposed therein. Since the intermediate shaft of the 2-cylinder rotary compressor described in the above-mentioned Patent Literature 1 is formed such that its cross section is of a substantially rugby-ball shape, the bore of the through hole of the partition plate (hereinafter, also referred to simply as "bore of the partition plate") in which the intermediate shaft is disposed needs to be larger than the maximum length (the length between the apexes) of the cross section of the intermediate shaft with the substantially rugby-ball shape. However, if the bore of the partition plate is increased, the sealing length of the piston that is fixed into the eccentric of the crankshaft so as to seal a low-pressure side space of the compression chamber from the high-pressure space in the bore side becomes insufficient. Accordingly, in the 2-cylinder rotary compressor described in the above mentioned Patent Literature 1, the refrigerant gas in the inner circumference side of the piston with high-pressure leaks into the low-pressure space side in the compression chamber resulting in decrease in mass flow of the refrigerant gas that is suctioned into the compression chamber; hence, disadvantageously, refrigeration capacity is decreased and compression efficiency is deteriorated. Now, in order to resolve the above disadvantages, a configuration with a thin columnar intermediate shaft may be considered. However, when the intermediate shaft is formed of a thin columnar shape, the rigidity of the crankshaft drops. Accordingly, the crankshaft is bent by the load of the refrigerant gas under compression and the formation of oil film inside the bearing that rotatably supports the crankshaft is hindered; hence, damage to the bearing due to lack of lubrication disadvantageously occurs.

[0005]
Incidentally, when the partition plate is composed of an integral component, after one end of the crankshaft is inserted through the through hole of the partition plate, the partition plate needs to be arranged to where the intermediate shaft is disposed. That is, when the partition plate is composed of an integral component, one of the eccentrics needs to be inserted through the through hole of the partition plate and the bore of the partition plate needs to be formed to be larger than the outer diameter of the relevant eccentric. Accordingly, when the partition plate is composed of an integral component, the bore of the partition plate becomes disadvantageously large when eccentricity of the eccentric is made large; hence, the sealing length of the piston becomes insufficient. Therefore, it is not possible to increase the eccentricity of the eccentric. As such, there has been conventionally proposed a rotary compressor in which the bore of the partition plate is formed to be smaller than the eccentric by divisionally forming the partition plate and assembling them so as to interpose the intermediate shaft therebetween. By dividing the partition plate as above, lack of the sealing length of the piston can be solved and the eccentricity of the eccentric can be made large. Accordingly, the volume of the compression chamber can be increased and the refrigeration capacity of the compressor can be improved. Further, when the volume of the compression chamber is not changed, since the compression chamber in the shaft direction becomes flatter, the bore of the cylinder (the bore of the through hole of the cylinder in which the eccentric and the piston are disposed) and the outer diameter of the piston can be made larger, thus, a long sealing portion, where the bore of the cylinder and the piston becomes adjacent to each other, can be obtained and compression efficiency can be improved.

[0006]
However, in a case in which the intermediate shaft is formed to have a cross section of a rugby-ball shape, as in Patent Literature 1, even when the partition plate is divisionally formed, the bore of the partition plate cannot be made smaller than the maximum length (the length between the apexes) of the cross section of the intermediate shaft with the substantially rugby-ball shape. Accordingly, in the case where the intermediate shaft is formed to have a cross section of a rugby-ball shape, as in Patent Literature 1, even when the partition plate is divisionally formed, disadvantages such as insufficient sealing length of the piston and leaking of the refrigerant gas in the inner circumference side of the piston with high-pressure into the low-pressure space side in the compression chamber cannot be resolved.

[0007]
The invention has been made to solve the above disadvantages and an object thereof is to provide a rotary compressor that is capable of achieving high output and high efficiency while maintaining reliability (rigidity) of a crankshaft. Solution to Problem

[0008]
A rotary compressor according to the invention includes a motor having a stator and a rotor; a crankshaft including a main shaft that is fixed to the rotor, a sub shaft that is provided on an opposite side in a shaft direction of the main shaft, a main shaft side eccentric and a sub shaft side eccentric that are formed to have a phase difference of substantially 180° and that are provided between the main shaft and the sub shaft, and an intermediate shaft provided between the main shaft side eccentric and the sub shaft side eccentric, the crankshaft being driven by the motor; a first piston being fitted to the main shaft side eccentric; a second piston being fitted to the sub shaft side eccentric; a first cylinder being formed with a cylindrical through hole, the first cylinder being formed with a compression chamber in the through hole arranged with the main shaft side eccentric and the first piston; a second cylinder being formed with a cylindrical through hole, the second cylinder being formed with a compression chamber in the through hole arranged with the sub shaft side eccentric and the second piston; and a partition plate being formed with a cylindrical through hole in which the intermediate shaft is disposed, the partition plate partitioning the compression chamber of the first cylinder from the compression chamber of the second cylinder. In the rotary compressor, a section of the intermediate shaft, orthogonal to the shaft direction, is formed into convex shapes in directions orthogonal to eccentric directions of the main shaft side eccentric and the sub shaft side eccentric with a first surface (A1), which is formed, in planer view, in a same position as a periphery of the main shaft side eccentric on a counter-eccentric side or formed on a shaft center side relative to the periphery and along the periphery; and with a second surface (A2), which is formed, in planer view, in a same position as a periphery of the sub shaft side eccentric on a counter-eccentric side or formed on a shaft center side relative to the periphery and along the periphery, and the intermediate shaft is formed of third surfaces (B) in which each convex end portion is arranged on the shaft center side relative to an interception C of imaginary extended lines of the first surface (A1) and the second surface (A2) in a section orthogonal to the shaft direction, and in which the convex end portion includes at least either one of a curved surface and a flat surface.

[Advantageous Effects of Invention]

[0009]
In the rotary compressor according to the invention, the section of the intermediate shaft, orthogonal to the shaft direction, is formed into convex shapes in directions orthogonal to the eccentric directions of the main shaft side eccentric and the sub shaft side eccentric with a first surface (A1), which is formed, in planer view, in the same position as the periphery of the main shaft side eccentric on the counter-eccentric side or is formed on the shaft center side relative to the periphery and along the periphery; and with the second surface (A2), which is formed, in planer view, in the same position as the periphery of the sub shaft side eccentric on the counter-eccentric side or is formed on the shaft center side relative to the periphery and along the periphery. Further, the intermediate shaft is formed of third surfaces (B) in which each convex end portion is arranged on the shaft center side relative to the interception C of imaginary extended lines of the first surface (A1) and the second surface (A2) in the section orthogonal to the shaft direction, and in which the convex end portion includes at least either one of a curved surface and a flat surface. Accordingly, since the rotary compressor according to the invention can make the bore of the partition plate small while improving the rigidity of the intermediate shaft, the compressor is capable of achieving high output and high efficiency while maintaining reliability of the crankshaft.

[Brief Description of Drawings]

[0010]
[Fig. 1] Fig. 1 is a diagram illustrating Embodiment 1 of the invention and is a longitudinal sectional view of a 2-cylinder rotary compressor.

[Fig. 2] Fig. 2 is a diagram illustrating Embodiment 1 of the invention and is cross-sectional views of an intermediate shaft 4e of a crankshaft 4 ((a) is a plan view omitting some parts of the crankshaft 4, (b) is a cross-sectional view taken along A-A of (a), and (c) is a cross-sectional view taken along B-B of (a)).

[Fig. 3] Fig. 3 is a diagram illustrating Embodiment 1 of the invention and is a diagram illustrating a state in which a first cylinder 8 and a main bearing 6 are fixed by bolting.

[Fig. 4] Fig. 4 is a diagram illustrating Embodiment 1 of the invention and is a diagram illustrating a state in which the crankshaft 4 is inserted into the main bearing 6 and in which a first piston 11a is made to pass over a sub shaft 4b, a sub shaft side eccentric 4d, and an intermediate shaft 4e and is assembled to the main shaft side eccentric 4c.

[Fig. 5] Fig. 5 is a diagram illustrating Embodiment 1 of the invention and is a diagram illustrating a state in which a partition plate 10 is temporarily assembled to the intermediate shaft 4e.

[Fig. 6] Fig. 6 is a diagram illustrating Embodiment 1 of the invention and is a diagram illustrating a state in which the partition plate 10 is assembled to the intermediate shaft 4e.

[Fig. 7] Fig. 7 is a diagram illustrating Embodiment 1 of the invention and is a diagram illustrating a state in which a second piston 11b is inserted into the sub shaft side eccentric 4d, a second cylinder 9 and a sub bearing 7 are fixed, and the second piston 11 b is inserted into the sub shaft 4b of the crankshaft 4.

[Fig. 8] Fig. 8 is a diagram illustrating Embodiment 1 of the invention and is a diagram illustrating a state in which the second cylinder 9 is fixed, from the outside of the sub bearing 7, to the first cylinder 8 with the partition plate 10 in between and in which the first cylinder 8 is concurrently fixed, from the outside of the main bearing 6, to the second cylinder 9 with the partition plate 10 in between.

[Fig. 9] Fig. 9 is a diagram illustrating Embodiment 1 of the invention and is a diagram illustrating the assembling process of the first piston 11a to the crankshaft 4 when relief shapes 11 a-1 are provided to the two edges of the bore of the first piston 11 a in the shaft direction.

[Fig. 10] Fig. 10 is a diagram illustrating Embodiment 1 of the invention and is a diagram comparing between Fig. 9 and Fig. 11 (Fig 10(a) is a comparative example and Fig. 10(b) is of the present embodiment).

[Fig. 11] Fig. 11 is a diagram illustrating the comparative example and is a diagram illustrating the assembling process of the first piston 11 a to the crankshaft 4.

[Fig. 12] Fig. 12 is a diagram illustrating the comparative example and is a diagram illustrating a crankshaft 4 provided with a step portion in the intermediate shaft 4e ((a) is a plan view omitting some parts of the crankshaft 4, (b) is a cross-sectional view taken along A-A of (a), and (c) is a cross-sectional view taken along B-B of (a)).

[Fig. 13] Fig. 13 is a diagram illustrating the comparative example and is a diagram illustrating the assembling process of the crankshaft 4 of Fig. 12 to the first piston 11a.

[Description of Embodiments]

[0011] Embodiment 1

Fig. 1 through Fig. 10 are diagrams illustrating Embodiment 1 of the invention. Fig. 1 is a longitudinal sectional view of a 2-cylinder rotary compressor 100; Fig. 2 is cross-sectional views of an intermediate shaft 4e of a crankshaft 4 ((a) is a plan view omitting some parts of the crankshaft 4, (b) is a cross-sectional view taken along A-A of (a), and (c) is a cross-sectional view taken along B-B of (a)); Fig. 3 is a diagram illustrating a state in which a first cylinder 8 and a main bearing 6 are fixed by bolting; Fig. 4 is a diagram illustrating Embodiment 1 of the invention and is a diagram illustrating a state in which the crankshaft 4 is inserted into the main bearing 6 and in which the first piston 11 a is made to pass over the sub shaft 4b, the sub shaft side eccentric 4d, and the intermediate shaft 4e and is assembled to the main shaft side eccentric 4c; Fig. 5 is a diagram illustrating a state in which a partition plate 10 is temporarily assembled to the intermediate shaft 4e; Fig. 6 is a diagram illustrating a state in which the partition plate 10 is assembled to the intermediate shaft 4e; Fig. 7 is a diagram illustrating a state in which a second piston 11b is inserted into the sub shaft side eccentric 4d, a second cylinder 9 and a sub bearing 7 are fixed, and the second piston 11b is inserted into the sub shaft 4b of the crankshaft 4; Fig. 8 is a diagram illustrating a state in which the second cylinder 9 is fixed, from the outside of the sub bearing 7, to the first cylinder 8 with the partition plate 10 in between and in which the first cylinder 8 is concurrently fixed, from the outside of the main bearing 6, to the second cylinder 9 with the partition plate 10 in between; Fig. 9 is a diagram illustrating the assembling process of the first piston 11a to the crankshaft 4 when relief shapes 11 a-1 are provided to the two edges of the bore of the first piston 11a in the shaft direction; and Fig. 10 is a diagram comparing between Fig. 9 and Fig. 11 (Fig 10(a) is a comparative example and Fig. 10(b) is of the present embodiment).

The 2-cylinder rotary compressor 100 according to Embodiment 1 will be described below with reference to Figs. 1 through 10.

[0012]
Referring to Fig. 1, a configuration of the 2-cylinder rotary compressor 100 will be described. The 2-cylinder rotary compressor 100 houses in a hermetic vessel 1 with a high-pressure atmosphere a motor 2 that includes a stator 2a and a rotor 2b and a compression mechanism 3 that is driven by the motor 2.

[0013]
The torque of the motor 2 is transmitted to the compression mechanism 3 through the crankshaft 4.

[0014]
The crankshaft 4 includes a main shaft 4a that is fixed to the rotor 2b of the motor 2, the sub shaft 4b that is provided on the opposite side of the main shaft 4a, the main shaft side eccentric 4c and the sub shaft side eccentric 4d with a predetermined phase difference (for example, 180°) that are provided between the main shaft 4a and the sub shaft 4b, and the intermediate shaft 4e that is provided between the main shaft side eccentric 4c and the sub shaft side eccentric 4d.

[0015]
The main bearing 6 is fitted to the main shaft 4a of the crankshaft 4 with a clearance for sliding in which the main shaft 4a is pivotally and rotatably supported by the main bearing 6.

[0016]
Further, the sub bearing 7 is fitted to the sub shaft 4b of the crankshaft 4 with a clearance for sliding in which the sub shaft 4b is pivotally and rotatably supported by the sub bearing 7.

[0017]
The compression mechanism 3 includes the first cylinder 8 on the main shaft 4a side and the second cylinder 9 on the sub shaft 4b side.

[0018]
The first cylinder 8 has a cylindrical through hole to which the first piston 11 a that is rotatably fitted to the main shaft side eccentric 4c of the crankshaft 4 is provided. Further, a first vane (not shown) that performs reciprocating motion in accordance with the rotation of the main shaft side eccentric 4c is provided.

[0019]
The opposite edges of the through hole in the shaft direction of the first cylinder 8, which accommodates the first piston 11a that is rotatably fitted to the main shaft side eccentric 4c of the crankshaft 4 and which accommodates the first vane, are covered by the main bearing 6 and the partition plate 10, thus forming a compression chamber.

[0020]
The first cylinder 8 is fixed inside the hermetic vessel 1.

[0021]
The second cylinder 9 also has a cylindrical through hole to which the second piston 11b that is rotatably fitted to the sub shaft side eccentric 4d of the crankshaft 4 is provided. Further, a second vane (not shown) that performs reciprocating motion in accordance with the rotation of the sub shaft side eccentric 4d is provided.

[0022]
The opposite edges of the through hole in the shaft direction of the second cylinder 9, which accommodates the second piston 11b that is rotatably fitted to the sub shaft side eccentric 4d of the crankshaft 4 and which accommodates the second vane, are covered by the sub bearing 7 and the partition plate 10, thus forming a compression chamber.

[0023]
As regards the compression mechanism 3, after bolting the first cylinder 8 and the main bearing 6 together and bolting the second cylinder 9 and the sub bearing 7 together, the partition plate 10 is sandwiched therebetween. The components are fixed by bolting the second cylinder 9 from outside the main bearing 6 and the first cylinder 8 from outside the sub bearing 7 in the shaft direction.

[0024]
A bolt 12 depicted in Fig. 1 is a portion of a bolt that bolts and fixes from the outside of the main bearing 6 to the second cylinder 9 in the shaft direction.

[0025]
A bolt 13 depicted in Fig. 1 is a portion of a bolt that bolts the second cylinder 9 and the sub bearing 7 together.

[0026]
An accumulator 40 is provided adjacent to the hermetic vessel 1. A suction connecting pipe 21 and a suction connecting pipe 22 are respectively connected to the first cylinder 8 and the second cylinder 9 of the accumulator 40.

[0027]
Refrigerant gas that has been compressed in the first cylinder 8 and the second cylinder 9 is discharged into the hermetic vessel 1 and is sent out into the refrigeration cycle of the refrigeration and air-conditioning apparatus through the discharge pipe 23.

[0028]
Further, electric power is supplied to the motor 2 from the glass terminal 24 through the lead wire 25.

[0029]
Although not shown, in the bottom portion of the hermetic vessel 1, lubricant oil (refrigerating machine oil) that lubricates each of the sliding portions of the compression mechanism 3 is retained.

[0030]
Supplying of the lubricant oil to each of the sliding portions of the compression mechanism 3 is performed through oil supply holes 20 provided in the crankshaft 4 in which the lubricant oil that is retained in the bottom portion of the hermetic vessel 1 is made to ascend along a bore 4f of the crankshaft 4 by centrifugal force exerted by rotation of the crankshaft 4. In the example of Fig. 1, the oil supply hole 20 is formed in four positions. From each of the respective oil supply holes, lubricant oil is supplied to the sliding portions between the main shaft 4a and the main bearing 6, the main shaft side eccentric 4c and the first piston 11a, the sub shaft side eccentric 4d and the second piston 11b, and the sub shaft 4b and the sub bearing 7.

[0031]
The crankshaft 4 employs a material with a Young's modulus of 150 GPa or more so that bending that is caused by the load of the compressed gas during operation is suppressed. Further, in order to suppress vibration during operation, the main shaft side eccentric 4c and the sub shaft side eccentric 4d are of a substantially same shape (same diameter and same length in the shaft direction) and have a substantially same eccentricity, so as to balance the centrifugal forces during rotation.

[0032]
In Embodiment 1, the partition plate 10 is composed of an integral component. Accordingly, by the following reason, the periphery of the main shaft side eccentric 4c on its counter-eccentric side is formed on the shaft center side relative to the periphery of the main shaft 4a. Further, the outer diameter of the sub shaft 4b is formed to be smaller than the outer diameter of the main shaft 4a, and the periphery of the sub shaft .. side eccentric 4d on its counter-eccentric side is formed on the counter-shaft center side relative to the periphery of the sub shaft 4b.

[0033]
As mentioned above, the sub shaft side eccentric 4d has the same shape and the same eccentricity as that of the main shaft side eccentric 4c. Accordingly, in a case in which the outer diameter of the sub shaft 4b and the outer diameter of the main shaft 4a are the same, when the periphery of the main shaft side eccentric 4c on the counter-eccentric side is formed on the shaft center side relative to the periphery of the main shaft 4a, then the periphery of the sub shaft side eccentric 4d on the counter-eccentric side is also formed on the shaft center side relative to the periphery of the sub shaft 4b. Then, as later described, when attempting to assemble the first piston 11a and the second piston 11b from the sub shaft 4b side, it will not be possible to insert the sub shaft side eccentric 4d through the first piston 11a and the second piston 11b. That is, the first piston 11a and the second piston 11b cannot be assembled to the main shaft side eccentric 4c and the sub shaft side eccentric 4d, respectively. Accordingly, in Embodiment 1, the assembling of the first piston 11a and the second piston 11b is enabled by forming the periphery of the sub shaft side eccentric 4d on the counter-eccentric side so as to be on the counter-shaft center side relative to the periphery of the sub shaft 4b. Further, the outer diameter of the main shaft 4a, which has no influence on the assembling of the first piston 11a and the second piston 11b, is made lager than the outer diameter of the sub shaft 4b so as to obtain rigidity of the crankshaft 4.

[0034]
Furthermore, in Embodiment 1, the shape of the intermediate shaft 4e is as illustrated in Fig. 2 in an aim to maintain the rigidity of the intermediate shaft 4e while making the eccentricity of each of the main shaft side eccentric 4c and the sub shaft side eccentric 4d large. Note that in Fig. 2(a), the crankshaft 4 is depicted such that the main shaft 4a is on the lower side of the drawing and the sub shaft 4b is on the upper side of the drawing.

[0035]
As illustrated in Fig. 2, the intermediate shaft 4e is formed with a surface A1 corresponding to the first surface of the invention, a surface A2 corresponding to the second surface of the invention, and a surfaces B corresponding to the third surfaces of the invention. Further, a section of the crankshaft 4 (more specifically, the intermediate shaft 4e) orthogonal to the shaft is convex-shaped in the directions orthogonal to the eccentric directions of the main shaft side eccentric 4c and the sub shaft side eccentric 4d.

[0036]
In more detail, the surface A1 is formed on the shaft center side relative to the periphery of the main shaft side eccentric 4c on the counter eccentric side and is shaped along the periphery of the main shaft side eccentric 4c on the counter eccentric side. Similarly, the surface A2 is formed on the shaft center side relative to the periphery of the sub shaft side eccentric 4d on the counter eccentric side and is shaped along the periphery of the sub shaft side eccentric 4d on the counter eccentric side. As above, by structuring the intermediate shaft 4e with the surfaces A1 and A2, the intermediate shaft 4e is shaped such that a section of the crankshaft 4 (more specifically, the intermediate shaft 4e) orthogonal to the shaft is convex shaped in the directions orthogonal to the eccentric directions of the main shaft side eccentric 4c and the sub shaft side eccentric 4d. Accordingly, the cross-sectional area of the intermediate shaft 4e is increased and the rigidity of the intermediate shaft can be increased.

[0037]
Here, the intermediate shaft 4e is disposed inside the through hole formed in the partition plate 10, as illustrated in Fig. 1. Accordingly, the bore 10a of the through hole of the partition plate 10 needs to be formed larger than the maximum length of the cross-section of the intermediate shaft 4e orthogonal to the shaft direction. At this point, in the above-mentioned intermediate shaft described in Patent Literature 1, the ends in the direction orthogonal to the eccentric directions of the main shaft side eccentric 4c and the sub shaft side eccentric 4d are positioned at interceptions C of an imaginary extended line of the surface A1 and an imaginary extended line of the surface A2 (see Fig. 2). Accordingly, the bore 10a of the partition plate 10 is disadvantageously large. Therefore, when attempting to make the eccentricity of each of the eccentrics (corresponding to the main shaft side eccentric 4c and the sub shaft side eccentric 4d of Embodiment 1) large, the sealing length of the piston (corresponding to the distance between the first piston 11a and the bore 10a of the partition plate 10 illustrated in Fig. 2(c), for example) becomes insufficient; hence, the refrigerant gas in the inner circumference side of the piston with high-pressure leaks into the low-pressure space side in the compression chamber resulting in decrease in mass flow of the refrigerant gas that is suctioned into the compression chamber, and disadvantageously decreasing the refrigeration capacity and deteriorating the compression efficiency.

[0038]
On the other hand, the intermediate shaft 4e according to Embodiment 1 is structured with surfaces B in the ends in the directions orthogonal to the eccentric directions of the main shaft side eccentric 4c and the sub shaft side eccentric 4d. Further, each surface B is formed on the shaft center side relative to the interception C of an imaginary extended line of the surface A1 and an imaginary extended line of the surface A2. Accordingly, the bore 10a of the partition plate 10 can be made small. Therefore, even if the eccentricity of each of the main shaft side eccentric 4c and the sub shaft side eccentric 4d is made large, the sealing length of each of the piston (corresponding to the distance between the first piston 11a and the bore 10a of the partition plate 10 illustrated in Fig. 2(c) and the distance between the second piston 11b and the bore 10a of the partition plate 10 illustrated in Fig. 2(b)) can be sufficiently obtained. Accordingly, by forming the intermediate shaft 4e as Embodiment 1, prevention of the refrigerant gas in the inner circumference side of the piston with high-pressure from leaking into the low-pressure space side in the compression chamber, which results in decrease in mass flow of the refrigerant gas that is suctioned into the compression chamber, can be implemented.

[0039]
Hence, a crankshaft 4 that is structured as Embodiment 1 allows the eccentricity of each of the main shaft side eccentric 4c and the sub shaft side eccentric 4d to be made large and the displacement volume of the compression chamber to be increased, thus, high output of the 2-cylinder rotary compressor 100 is achieved.

[0040]
In other words, the volume of the compression chamber can be made smaller in obtaining the same output, thus, it is possible to downsize and reduce the weight of the 2-cylinder rotary compressor 100.

[0041]
Furthermore, when the volume of the compression chamber is not changed, since the compression chamber in the shaft direction becomes flatter, that is, since the thickness of the first cylinder 8 and the second cylinder 9 becomes smaller, the cylinder bore of the first cylinder 8 and the second cylinder 9 and the outer diameter of the first piston 11a and the second piston 11b can be made large accordingly. Hence, it will be possible to obtain a long sealing portion between the bore of the first cylinder 8 and the first piston 11a and between the bore of the second cylinder 9 and the second piston 11b, and, thus, improve the compression efficiency.

[0042]
Note that the shape of the intermediate shaft 4e is not limited to the shape described above and may be as described below, for example. For example, the surfaces A1 and A2 of the intermediate shaft 4e may be formed in the same position as the periphery of the main shaft side eccentric 4c and the sub shaft side eccentric 4d on the counter-eccentric side, respectively. As will be described later, the first piston 11a is fitted to the main shaft side eccentric 4c after passing through the sub shaft side eccentric 4d and the intermediate shaft 4e. Here, if the surfaces A1 and A2 of the intermediate shaft 4e do not bulge out from the peripheries of the main shaft side eccentric 4c and the sub shaft side eccentric 4d on the counter-eccentric side, then it will be possible to fit the first piston 11a to the main shaft side eccentric 4c. Further, for example, a portion or the front portion of each surface B may be a flat surface. As long as each surface B is formed on the shaft center side relative to the interception C of an imaginary extended line of the surface A1 and an imaginary extended line of the surface A2, the bore 10a of the partition plate 10 can be made small and, thus, obtain the above advantages.

[0043]
The assembling process of the compression mechanism 3 will be described subsequently with reference to Figs. 3 to 8.

(1) As shown in Fig. 3, first, the first cylinder 8 and the main bearing 6 are fixed by fastening with bolts 14. A plurality of bolts 14 is used.

(2) As shown in Fig. 4, the main shaft 4a of the crankshaft 4 is inserted to the main bearing 6 from the first cylinder 8 side. Next, the first piston 11a is made to pass over the sub shaft 4b, the sub shaft side eccentric 4d, and the intermediate shaft 4e in this order and is assembled to the main shaft side eccentric 4c.

(3) As shown in Fig. 5, the partition plate 10 is made to pass over the sub shaft 4b and the sub shaft side eccentric 4d and is assembled to the intermediate shaft 4e. In this state, as shown by an arrow, since the partition plate 10 is only made to pass over in the shaft direction, the center of each of the partition plate 10 and the first cylinder 8 does not agree with each other.

(4) As shown in Fig. 6, the partition plate 10 is shifted to a direction orthogonal to the shaft and is set so that the center agrees with that of the first cylinder 8. This is done so that the position of a bolt run-through hole 10b provided to the partition plate 10, a bolt run-through hole 8a of the first cylinder 8, and a bolt run-through hole 6a of the main bearing 6 are in alignment and so that the later mentioned bolt can be inserted therethrough.

(5) As shown in Fig. 7, after passing the second piston 11b over the sub shaft 4b, the second piston 11b is fitted to the sub shaft side eccentric 4d.

(6) The second cylinder 9 and the sub bearing 7 are fixed with plural bolts 13. This is fitted to the sub shaft 4b of the crankshaft 4.

(7) As shown in Fig. 8, the second cylinder 9 is fixed together with the first cylinder 8, with the partition plate 10 therebetween, with plural bolts 15 from the outside of the sub bearing 7. Furthermore, concurrently, the first cylinder 8 is fixed together with the second cylinder 9, with the partition plate 10 therebetween, with plural bolts 12 from the outside of the main bearing 6.

[0044]
At this point, the conventional 2-cylinder rotary compressor described in the above-mentioned Patent Literature 1 encountered a problem described below when assembling the compression mechanism in a manner illustrated in Figs. 3 to 8. That is, as mentioned above, since the conventional 2-cylinder rotary compressor described in Patent Literature 1 needs to make the bore of the partition plate large, the sealing length of the piston becomes insufficient, thus, disadvantageously causing decrease in refrigeration capacity and deterioration of compression efficiency. In order to prevent this, it appears that the bore of the partition plate should be formed as small as possible so as to be approximate to the periphery of the intermediate shaft as much as possible. However, if the bore of the partition plate is made thus small, in the case of setting the center axis of the bore of the partition plate and the center axis of the cylinder to agree with each other (corresponding to the process in Fig. 6 of Embodiment 1), the bore of the partition plate and the intermediate shaft may interfere with each other due to a machining error and the like of the components of the compression mechanism, thus impeding the center axes to be in agreement. Accordingly, in the process corresponding to Fig. 6 of Embodiment 1, the boits (corresponding to bofts 12 and 15) that are to be inserted into the bolt run-through holes are not allowed to penetrate through the partition plate. The compression mechanism will have to be re-assembled; hence, assembling work efficiency is reduced.

[0045]
In contrast, in the 2-cylinder rotary compressor 100 according to Embodiment 1, even if each of the sealing length of the piston (corresponding to the distance between the first piston 11a and the bore 10a of the partition plate 10 illustrated in Fig. 2(c) and the distance between the second piston 11b and the bore 10a of the partition plate 10 illustrated in Fig. 2(b)) is made sufficiently long, adequate space between the bore 10a of the partition plate 10 and the periphery of the intermediate shaft 4e can be formed. Accordingly, in the process illustrated in Fig. 6, since the bore 10a of the partition plate 10 and the intermediate shaft 4e do not interfere with each other, the bolts 12 and 15 can be surely inserted through the bolt run-through holes 10b of the partition plate 10 in the process illustrated in Fig. 8. Therefore, there is no need to re-assemble the compression mechanism 3, and the assembling work efficiency is improved.

[0046]
Note that crankshafts other than the one described in Patent Literature 1, whose intermediate shaft has been devised to improve its rigidity, has been proposed. With reference to the comparative example (an example of a known crankshaft that is devised to improve the rigidity of the intermediate shaft) illustrated in the subsequent Figs. 12 and 13, description will be made showing that even in such a conventional crankshaft, the disadvantages solved by the 2-cylinder rotary compressor according to Embodiment 1 cannot be solved.

[0047]
As shown in the comparative example illustrated in Figs. 12 and 13, conventionally, there is one in which the intermediate shaft 4e is divided into a first intermediate shaft 4e-1 on the main shaft side eccentric 4c side and a second intermediate shaft 4e-2 on the sub shaft side eccentric 4d side in order to suppress bending of the crankshaft caused by the compression load.

[0048]
As illustrated in Fig. 12(a), the first intermediate shaft 4e-1 and the second intermediate shaft 4e-2 are formed so as to be deviated in the radial direction. The first intermediate shaft 4e-1 is eccentricated (protruded) in the eccentric direction of the main shaft side eccentric 4c. The second intermediate shaft 4e-2 is eccentricated (protruded) in the eccentric direction of the sub shaft side eccentric 4d.

[0049]
As shown in Fig. 12(c), which is a cross-section taken along B-B of Fig. 12(a), the space between the first intermediate shaft 4e-1 and the bore 10a of the partition plate 10 is small, especially between the periphery on the eccentric side of the first intermediate shaft 4e-1 and the bore 10a.

[0050]
As shown in Fig. 12(b), which is a cross-section taken along A-A of Fig. 12(a), the space between the second intermediate shaft 4e-2 and the bore 10a of the partition plate 10 is small, especially between the periphery on the eccentric side of the second intermediate shaft 4e-2 and the bore 10a.

[0051]
In the comparative example illustrated in Fig. 12, a process illustrated in Fig. 13(a) to (d) is needed to set the partition plate 10 to the intermediate shaft 4e. Namely, when setting the partition plate 10 to the intermediate shaft 4e, the partition plate needs to be tilted at the boundary of the second intermediate shaft 4e-2 and the first intermediate shaft 4e-1, and shifted to the main shaft side eccentric 4c direction; and the tilting of the partition plate 10 needs to be adjusted.

[0052]
Further, since the first intermediate shaft 4e-1 and the second intermediate shaft 4e-2 protrude in the eccentric direction and the space between the bore 10a of the partition plate 10 is small, the periphery of each of the first intermediate shaft 4e-1 and the second intermediate shaft 4e-2 on the eccentric side is likely to be in contact with the bore 10a of the partition plate 10; hence, there has been difficulty when setting the center axis of the partition plate 10 to agree with that of the first cylinder 8, disadvantageously. When a workpiece in which the center axis is out of alignment is sent out to the after process, since the bolts 12 and 15 illustrated in Fig. 8 do not pass through the partition plate 10, re-assembling is required, thus, assembling work efficiency is reduced.

[0053]
In contrast, in the crankshaft 4 according to Embodiment 1, different from the comparative example illustrated in Figs. 12 and 13, the intermediate shaft 4e does not protrude out from the main shaft side eccentric 4c and the sub shaft side eccentric 4d and there is no boundary. The intermediate shaft 4e is defined within an area where the main shaft side eccentric 4c and the sub shaft side eccentric 4d overlap each other.

[0054]
Accordingly, it will be possible to move the partition plate 10 smoothly when the partition plate 10 is fitted to the intermediate shaft 4e, as illustrated in Figs. 5 and 6.

[0055]
Further, as mentioned above while referring to Fig. 2, a wide space between the intermediate shaft 4e and the bore 10a of the partition plate 10 can be obtained and there will be no contact between the two. There is no obstacle when setting the partition plate 10 and the first cylinder 8 so that their center axes agree with each other, and, thus, assembling work efficiency is improved.

[0056]
Furthermore, the comparative example illustrated in Figs. 12 and 13 further has the below problem when compared with the crankshaft 4 according to Embodiment 1.

In the 2-cylinder rotary compressor 100, the running torque of the motor 2 is transmitted to the rotor 2b and the crankshaft 4 to which the rotor 2b is shrink fitted. The first piston 11a and the second piston 11b that are fitted to the main shaft side eccentric 4c and sub shaft side eccentric 4d, respectively, of the crankshaft 4 are made to eccentrically rotate in the compression chambers that include air chambers of the first cylinder 8 and the second cylinder 9, the first piston 11a and the second piston 11b, and the first vane and the second vane, so as to compress the refrigerant.

[0057]
Supplying of oil to each of the sliding portions of the compression mechanism 3 is performed through an oil supply hole 20 provided in the crankshaft in which the lubricant oil that is retained in the bottom portion of the hermetic vessel 1 is made to ascend along a bore 4f of the crankshaft 4 with centrifugal force exerted by rotation of the crankshaft 4.

[0058]
Here, the lubricant oil that is discharged from each oil supply hole 20 is supplied to the corresponding sliding portion of the compression mechanism 3, as well as being accumulated in a high-pressure space 30 (see Fig. 1) that is surrounded by the intermediate shaft 4e and the bore 10a of the partition plate 10. It is known that driving power loss of the crankshaft 4 is caused when the intermediate shaft 4e rotates at high speed in the high-pressure space 30 mixing the lubricant oil. As in the comparative example (Figs. 12 and 13), when the first intermediate shaft 4e-1 of the intermediate shaft 4e is eccentricated (protruded) in the eccentric direction of the main shaft side eccentric 4c and when the second intermediate shaft 4e-2 is eccentricated (protruded) in the eccentric direction of the sub shaft side eccentric 4d, the radius of gyration of the intermediate shaft 4e becomes large and the above loss caused by mixing is increased.

[0059]
As illustrated in Fig. 2, in the crankshaft 4 according to Embodiment 1, the intermediate shaft 4e can be designed to have a small radius of gyration and to have a wide space between the bore 10a of the partition plate 10; hence, loss caused by mixing of the lubricant oil can be substantially reduced. If reduction of loss caused by mixing is to be solely pursued, naturally, the intermediate shaft 4e can have a circular shape with a radius equivalent to or smaller than that of the sub shaft 4b. However, when suppression of bending of the crankshaft 4 is taken into consideration, the shape of Embodiment 1, which maximizes the cross-sectional area of the intermediate shaft 4e within the range that does not hinder the assembling workability, is the optimum shape.

[0060]
Incidentally, the 2-cylinder rotary compressor 100 according to Embodiment 1 has devised the compression mechanism 3 to reduce its length in the shaft direction. Here, if the length of each of the first piston 11a and the second piston 11b in the shaft direction is not to be changed, that is, if the height of each compression chamber is not to be changed, there arises a concern that the first piston 11a may not pass through the intermediate shaft 4e. In order to resolve this matter of concern, methods such as reducing the length of at least either one of the main shaft side eccentric 4c and the sub shaft side eccentric 4d in the shaft direction, as described below, and reducing the length of the intermediate shaft 4e in the shaft direction, as described below, can be conceived.

[0061]
Although not shown, the method of reducing the length of at least either one of the main shaft side eccentric 4c and the sub shaft side eccentric 4d in the shaft direction is one in which the length of at least either one of the main shaft side eccentric 4c and the sub shaft side eccentric 4d in the shaft direction is made shorter than the length of the corresponding piston (the first piston 11a and the second piston 11b) to which the relevant eccentric is assembled. In this case, the eccentric, which is reduced of its length in the shaft direction, reduces its length by shaving its side on the intermediate shaft 4e side.

[0062]
If the length of the first piston 11a in the shaft direction is greater than the length of the intermediate shaft 4e in the shaft direction, it will be possible to assemble the first piston 11 a to the main shaft side eccentric 4c.

[0063]
That is, the length of at least either one of the main shaft side eccentric 4c and the sub shaft side eccentric 4d in the shaft direction is made shorter than the length of the corresponding piston (the first piston 11a and the second piston 11b) to which the relevant eccentric is assembled such that the length of the intermediate shaft 4e in the shaft direction becomes a substantially minimum size that allows the first piston 11a to be assembled to the main shaft side eccentric 4c. Accordingly, it will be possible to reduce the length of the compression mechanism 3 in the shaft direction without changing the length of each of the first piston 11a and the second piston 11b in the shaft direction.

[0064]
Another method of reducing the length of the compression mechanism 3 in the shaft direction is, as illustrated in Fig. 9, to reduce the length of the intermediate shaft 4e in the shaft direction than that of the first piston 11 a in the shaft direction and to provide relief shapes 11a-1 to the two edges of the bore of the first piston 11a in the shaft direction in order to allow assembling of the first piston 11a to the main shaft side eccentric 4c. Each relief shape 11a-1 is formed with a bevel, step, or the like.

[0065]
Referring to Fig. 9, a process of assembling the first piston 11a to the main shaft side eccentric 4c will be described.

(1) As shown in Fig. 9(a), the first piston 11a is passed over the sub shaft 4b and the sub shaft side eccentric 4d, and one end of the first piston 11 a in the shaft direction is abutted to the main shaft side eccentric 4c.

(2) Next, as shown in Fig. 9(b), the first piston 1a is tilted (counterclockwise in Fig. 9(b)).

(3) Further, as shown in Fig. 9(c), the first piston 11a is moved to the eccentric direction of the main shaft side eccentric 4c in the tilted state. The first piston 11a is moved in the tilted state until the bore of the first piston 11a abuts the periphery of the main shaft side eccentric 4c in the counter-eccentric direction.

(4) Finally, the first piston 11a is fitted to the main shaft side eccentric 4c.

[0066]
Before describing the advantageous effect of providing the relief shapes 11a-1to the two edges of the bore of the first piston 11a in the shaft direction, referring to Fig. 11, a comparative example in which the length of at least either one of the main shaft side eccentric 4c and the sub shaft side eccentric 4d in the shaft direction is not reduced or the length of the intermediate shaft 4e in the shaft direction is not reduced will be described.

[0067]
The assembling process of the comparative example illustrated in Fig. 11 is as follows.

(1) As shown in Fig. 11(a), the first piston 11a is passed over the sub shaft 4b and the sub shaft side eccentric 4d, and one end of the first piston 11a in the shaft direction is abutted to the main shaft side eccentric 4c.

(2) As shown in Fig. 11(b), the first piston 11a is moved to the main shaft side eccentric 4c side at the intermediate shaft 4e.

(3) As shown in Fig. 11(c), the first piston 11a is fitted to the main shaft side eccentric 4c.

[0068]
Fig. 10 is a diagram comparing Embodiment 1 illustrated in Fig. 9, provided with the relief shapes 11 a-1 to the two edges of the bore of the first piston 11a in the shaft direction, and the comparative example illustrated in Fig. 11. Fig. 10(a) is a diagram corresponding to Fig. 11(c), and Fig. 10(b) is a diagram corresponding to Fig. 9(d).

[0069]
The length of the intermediate shaft 4e, in the shaft direction, of the crankshaft 4 illustrated in Fig. 9, provided with the first piston 11a having the relief shapes 11a-1 to the two edges of the bore in the shaft direction, is shorter than the intermediate shaft 4e of the comparative example in the shaft direction by dimension d. Accordingly, the length of the compression mechanism 3 in the shaft direction can be shortened by dimension d.

[0070]
As describe above, an advantage of being able to design a downsized compression mechanism can be enjoyed with the method such as making the length of at least either one of the main shaft side eccentric 4c and the sub shaft side eccentric 4d in the shaft direction shorter than the length of the corresponding piston (the first piston 11a and the second piston 11b) to which the relevant eccentric is assembled or with the method such as reducing the length of the intermediate shaft 4e in the shaft direction than that of the first piston 11 a in the shaft direction and providing the relief shapes 11 a-1 to the two edges of the bore of the first piston 11a in the shaft direction in order to allow assembling of the first piston 11a to the main shaft side eccentric 4c.

[0071]
Further, the distance between the main shaft side eccentric 4c or the sub shaft side eccentric 4d serving as a point of action of the load of the compressed gas and the main bearing 6 or the sub bearing 7 serving as a support point can be made small; hence, the bending of the crankshaft 4 under the same gas load can be suppressed. When the bending of the crankshaft 4 becomes large, the inclination of the crankshaft 4 relative to the main bearing 6 or the sub bearing 7 becomes large, and partial contact occurs. However, the reliability of the main bearing 6 or the sub bearing 7 can be improved by suppressing occurrence of partial contact by suppressing the bending of the crankshaft 4.

[0072]
Note that the method such as making the length of at least either one of the main shaft side eccentric 4c and the sub shaft side eccentric 4d in the shaft direction shorter than the length of the corresponding piston (the first piston 11 a and the second piston 11b) to which the relevant eccentric is assembled and the method such as reducing the length of the intermediate shaft 4e in the shaft direction than that of the first piston 11 a in the shaft direction and providing the relief shapes 11a-1 to the two edges of the bore of the first piston 11a in the shaft direction in order to allow assembling of the first piston 11a to the main shaft side eccentric 4c may be performed in combination. Accordingly, assembling of the first piston 11a to the main shaft side eccentric 4c is further facilitated.

[0073]
In the 2-cylinder rotary compressor 100 configured as Embodiment 1, with the surfaces A1 and A2, the intermediate shaft 4e is shaped such that a section of the crankshaft 4 (more specifically, the intermediate shaft 4e) orthogonal to the shaft is convex shaped in the directions orthogonal to the eccentric directions of the main shaft side eccentric 4c and the sub shaft side eccentric 4d. Further, each surface B serving as the convex end is formed on the shaft center side relative to the interception C of an imaginary extended line of the surface A1 and an imaginary extended line of the surface A2. Accordingly, since the 2-cylinder rotary compressor 100 according to Embodiment 1 can make the bore of the partition plate small while improving the rigidity of the intermediate shaft, the compressor is capable of achieving high output and high efficiency while maintaining reliability of the crankshaft 4.

[0074]
Note that although in Embodiment 1, description has been given with a partition plate 10 that is composed of an integral component, naturally, a partition plate 10 that is divided into plural pieces by a section through the bore 10a may be employed. In this case, the partition plates 10 can be assembled so as to sandwich the intermediate shaft 4e, thus, the bore 10a of the partition plates 10 can be formed smaller than the outer diameter of each of the main shaft side eccentric 4 and the sub shaft side eccentric 4d.

Accordingly, compared with the case in which a partition plate 10 that is composed of an integral component is employed, the eccentricity of the main shaft side eccentric 4c and the sub shaft side eccentric 4d can be made even larger. Accordingly, the volume of the compression chamber can be increased further and the refrigeration capacity of the compressor can be improved further. In other words, the volume of the compression chamber can be made smaller in obtaining the same output, thus, it is possible to further downsize and reduce the weight of the 2-cylinder rotary compressor 100. Further, in a case in which the volume of the compression chamber is not changed, it will be possible to obtain longer sealing portion between the bore of the first cylinder 8 and the first piston 11a and between the bore of the second cylinder 9 and the second piston 11b, and, thus, further improve the compression efficiency.

[0075]
In addition, when divisionally formed partition plates 10 are used, there will be no need to pass the bore 10a of each partition plate 10 through the sub shaft 4b while assembling the compression mechanism 3. Accordingly, the outer diameter of the sub shaft 4b may be formed to have the same largeness as that of the main shaft 4a such that the periphery of the sub shaft side eccentric 4d on the counter-eccentric side is on the shaft center side relative to the periphery of the sub shaft 4b, thus, increasing the rigidity of the crankshaft 4. Here, the surface B of the intermediate shaft 4e may be formed on the shaft center side relative to the periphery of the sub shaft 4b, and, further, the bore 10a of the partition plate 10 may also be formed on the shaft center side relative to the periphery of the sub shaft 4b. It will be possible to make the eccentricity of the main shaft side eccentric 4c and the sub shaft side eccentric 4d still larger.

[0076]
Additionally, in Embodiment 1, when assembling the compression mechanism 3, although the first piston 11a, the second piston 11b, the partition plate 10, and the like are assembled from the sub shaft 4b side, they may be assembled from the main shaft 4a side. In a case in which a partition plate 10 composed of an integral component is used, the periphery of the main shaft side eccentric 4c on the counter-eccentric side may be formed on the counter-shaft center side relative to the periphery of the main shaft 4a so as to allow the first piston 11a, the second piston 11b, the partition plate 10, and the like to be assembled. In this case, it goes without saying that the rigidity of the crankshaft 4 may be improved by enlarging the outer diameter of the sub shaft 4b that has no influence on the assembling of the first piston 11a, the second piston 11b, the partition plate 10, and the like.

[0077]
Furthermore, in Embodiment 1, description is made with a 2-cylinder rotary compressor, in which the pressures of the suction refrigerants and the pressure of the discharge refrigerants are the same in each of the compression chambers, as an example; however, it goes without saying that a 2-stage rotary compressor, which compresses low-pressure refrigerant gas into refrigerant gas with intermediate-pressure in a low-stage side compression chamber and which compresses intermediate-pressure refrigerant gas into high-pressure refrigerant gas in a high-stage side compression chamber, may embody the invention.

[Reference Signs List]

[0078]
1 hermetic vessel; 2 motor; 2a stator; 2b rotor; 3 compression mechanism; 4 crankshaft; 4a main shaft; 4b sub shaft; 4c main shaft side eccentric; 4d sub shaft side eccentric; 4e intermediate shaft; 4e-1 first intermediate shaft; 4e-2 second intermediate shaft; 4f bore; 6 main bearing; 6a bolt run-through hole; 7 sub bearing; 8 first cylinder; 8a bolt run-through hole; 9 second cylinder; 10 partition plate; 10a bore; 10b bolt run-through hole; 11a first piston; 11a-1 relief shape; 11b second piston; 12 bolt; 13 bolt; 14 bolt; 20 oil supply hole; 21 suction connecting pipe; 22 suction connecting pipe; 23 discharge pipe; 24 glass terminal; 25 lead wire; 30 high-pressure space; 40 accumulator; 100 2-cylinder rotary compressor.

[Name of Document]

CLAIMS

[Claim 1]
A rotary compressor, comprising;
a motor including a stator and a rotor;
a crankshaft including a main shaft that is fixed to the rotor, a sub shaft that is provided on an opposite side in a shaft direction of the main shaft, a main shaft side eccentric and a sub shaft side eccentric that are formed to have a phase difference of substantially 180° and that are provided between the main shaft and the sub shaft, and an intermediate shaft provided between the main shaft side eccentric and the sub shaft side eccentric, the crankshaft being driven by the motor;
a first piston being fitted to the main shaft side eccentric;
a second piston being fitted to the sub shaft side eccentric;
a first cylinder being formed with a cylindrical through hole, the first cylinder being formed with a compression chamber in the through hole arranged with the main shaft side eccentric and the first piston;
a second cylinder being formed with a cylindrical through hole, the second cylinder being formed with a compression chamber in the through hole arranged with the sub shaft side eccentric and the second piston; and
a partition plate being formed with a cylindrical through hole in which the intermediate shaft is disposed, the partition plate partitioning the compression chamber of the first cylinder from the compression chamber of the second cylinder, wherein

a section of the intermediate shaft, orthogonal to the shaft direction, is formed into convex shapes in directions orthogonal to eccentric directions of the main shaft side eccentric and the sub shaft side eccentric with a first surface (A1), which is formed, in planer view, in a same position as a periphery of the main shaft side eccentric on a counter-eccentric side or formed on a shaft center side relative to the periphery and along the periphery; and with a second surface (A2), which is formed, in planer view, in a same position as a periphery of the sub shaft side eccentric on a counter-eccentric side or formed on a shaft center side relative to the periphery and along the periphery, and the intermediate shaft is formed of third surfaces (B) in which each convex end portion is arranged on the shaft center side relative to an interception C of imaginary extended lines of the first surface (A1) and the second surface (A2) in a section orthogonal to the shaft direction, and in which the convex end portion includes at least either one of a curved surface and a flat surface.

[Claim 2]
The rotary compressor of claim 1, wherein the partition plate is divided into plural pieces by a section through the through hole formed in the partition plate.

[Claim 3]
The rotary compressor of claim 1, wherein the partition plate is formed of an integral component, the first piston and the second piston are fitted from the sub shaft side, a periphery of the sub shaft on a counter-eccentric side of the sub shaft side eccentric is formed on the shaft center side relative to a periphery of the sub shaft side eccentric on the counter-eccentric side, and an outer diameter of the sub shaft is formed to be smaller than an outer diameter of the main shaft.

[Claim 4]
The rotary compressor of claim 1, wherein the partition plate is formed of an integral component, the first piston and the second piston are fitted from the main shaft side, a periphery of the main shaft on a counter-eccentric side of the main shaft side eccentric is formed on the shaft center side relative to a periphery of the main shaft side eccentric on the counter-eccentric side, and an outer diameter of the main shaft is formed to be smaller than an outer diameter of the sub shaft.

[Claim 5]
The rotary compressor of any one of claim 1 to 4, wherein the crankshaft is formed of a material having a Young's modulus of 150 GPa or more.