[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]
A multi-cylinder rotary compressor is known, in which low-pressure refrigerant gas is compressed into high-pressure refrigerant gas in each of the plurality of compression chambers, and a multi-stage rotary compressor is known, in which low-pressure gas is sequentially compressed in a plurality of compression chambers to generate high-pressure refrigerant gas. Such compressors with multiple compression chambers include, in their crankshaft, multiple eccentrics that are disposed in the cylinders and an intermediate shaft disposed between the adjacent eccentrics. Further, in such compressors, one attempting to achieve high output and high efficiency by increasing the eccentricity of the eccentric has been conventionally proposed, such that "the eccentrics of a crankshaft 2a that are 180° opposed to each other are formed with different diameters d01 and d02, the outer diameter d1 on the upper end plate side of the crankshaft 2a and the outer diameter d2 on the lower end plate side are made to differ from each other, and a central hole in a partition plate 4 is set to a size that allows insertion of only the eccentric with the smaller diameter, thereby increasing the eccentricity" (see Patent Literature 1, for example).

[Citation List]

[Patent Literature]

[0003]

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 5-10279 (Abstract, Fig. 2)

[Summary of Invention]

[Technical Problem]

[0004]
However, in the 2-cylinder rotary compressor described in Patent Literature 1, since each eccentric has a different outer diameter, the gas load that acts on the eccentric of the crankshaft when the refrigerant gas is compressed is different in each eccentric. Accordingly, the forces on the crankshaft become unbalanced and, as a result, the moments in the rotation direction that are normally canceled out are not canceled out but strongly act on the rotational direction. Accordingly, the 2-cylinder rotary compressor described in Patent Literature 1 has problems such as drop of reliability of the crankshaft and generation of abnormal vibration and noise of the compressor.

[0005]
The invention has been made to solve the above problems and an object thereof is to provide a rotary compressor that is capable of achieving high output and high efficiency while maintaining reliability of the crankshaft.

[Solution to Problem]

[0006]
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 plurality of eccentrics that are formed to have a predetermined phase difference, and an intermediate shaft provided between the adjacent eccentrics, the crankshaft being driven by the motor; a plurality of cylinders each being formed with a cylindrical through hole, each of the cylinders being formed with a compression chamber in the through hole arranged with the corresponding one of the eccentrics; and a partition plate being formed with a cylindrical through hole in which the intermediate shaft is disposed, the partition plate partitioning adjacent compression chambers of the cylinders, In which a periphery of the intermediate shaft is formed on a peripheral side relative to a periphery of each eccentric on a counter-eccentric side, the partition plate is divided into plural plates by a section through the cylindrical through hole formed in the partition plate, and a bore of the through hole of the partition plate is larger than an outer diameter of the intermediate shaft and is smaller than an outer diameter of each eccentric.

[0007]
Furthermore, a rotary compressor according to the invention includes 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 plurality of eccentrics that are formed to have a predetermined phase difference, and an intermediate shaft provided between the adjacent eccentrics, the crankshaft being driven by the motor; a plurality of pistons each being fitted to the corresponding one of the eccentrics; a plurality of cylinders each being formed with a cylindrical through hole, each of the cylinders being formed with a compression chamber in the through hole arranged with the corresponding one of the eccentrics and the corresponding one of the pistons; and a partition plate being formed with a cylindrical through hole in which the intermediate shaft is disposed, the partition plate partitioning adjacent compression chambers of the cylinders, in which a periphery of the intermediate shaft is formed on a peripheral side relative to a periphery of each eccentric on a counter-eccentric side, the partition plate is divided into plural plates by a section through the cylindrical through hole formed in the partition plate, a bore of the through hole of the partition plate is larger than an outer diameter of the intermediate shaft and is smaller than an outer diameter of each eccentric, and a periphery of each piston on a counter-eccentric side is formed on a peripheral side relative to the bore of the through hole of the partition plate.

[Advantageous Effects of Invention]

[0008]
In the rotary compressor according to the invention, the periphery of the intermediate shaft is formed on the peripheral side relative to the periphery of each eccentric on the counter-eccentric side, the partition plate is divided into plural plates by a section through the through hole formed in the partition plate, and the bore of the through hole of the partition plate is larger than the outer diameter of the intermediate shaft and is smaller than the outer diameter of each eccentric. Accordingly, it will be possible to increase the eccentricity of each eccentric and achieve high output and high efficiency of the rotary compressor. Furthermore, since the rotary compressor according to the invention allows the eccentricity of each eccentric to be increased without the outer diameter of each eccentric be different, the gas load acting on each eccentric when compressing the refrigerant gas can be made substantially the same and the moments in the rotation direction can be canceled out. Accordingly, the rotary compressor according to the invention is capable of achieving high output and high efficiency while obtaining the reliability of the crankshaft.

[Brief Description of Drawings] [0009]

[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 100.

[Fig. 2] Fig. 2 is a diagram illustrating Embodiment 1 of the invention and is a longitudinal sectional view of a compression mechanism 3 of the 2-cylinder rotary compressor 100.

[Fig. 3] Fig. 3 is a diagram illustrating Embodiment 1 of the invention and is another longitudinal sectional view of the compression mechanism 3 of the 2-cylinder rotary compressor 100.

[Fig. 4] Fig. 4 is a diagram illustrating Embodiment 1 of the invention and is a cross-sectional view taken along Z-Z of Fig. 2.

[Fig. 5] Fig. 5 is a diagram illustrating Embodiment 1 of the invention and is a diagram illustrating an assembling process of a first piston 11a to a crankshaft 4 when relief shapes 11a-1 are provided to the two edges of a bore of the first piston 11a in the shaft direction.

[Fig. 6] Fig. 6 is a diagram illustrating Embodiment 1 of the invention and is a diagram comparing between Fig. 5 and Fig. 7 (Fig 6(a) is a comparative example and Fig. 10(b) is of the present embodiment).

[Fig. 7] Fig. 7 is a diagram illustrating the comparative example and is a diagram illustrating the assembling process of the first piston 11a to the crankshaft 4.

[Fig. 8] Fig. 8 is a diagram illustrating Embodiment 2 of the invention and is a longitudinal sectional view of a compression mechanism 3 of a 2-cylinder rotary compressor 100. [Description of Embodiments]

[0010] Embodiment 1
Figs 1 through 6 are diagrams illustrating Embodiment 1. Fig. 1 is a longitudinal sectional view of a 2-cylinder rotary compressor 100; Figs 2 and 3 are longitudinal sectional views of a compression mechanism 3 of the 2-cylinder rotary compressor 100; Fig. 4 is a cross-sectional view taken along Z-Z of Fig. 2; Fig. 5 is a diagram illustrating an assembling process of a first piston 11a to a crankshaft 4 when relief shapes 11 a-1 are provided to the two edges of a bore of the first piston 11 a in the shaft direction; Fig. 6 is a diagram comparing between Fig. 5 and Fig. 7 (Fig 6(a) is a comparative example and Fig. 6(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 6.

[0011]
Referring to Fig. 1, the 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.

[0012]
The torque of the motor 2 is transmitted to the compression mechanism 3 through the crankshaft 4.

[0013]
The crankshaft 4 includes a main shaft 4a that is fixed to the rotor 2b of the motor 2, a sub shaft 4b that is provided on the opposite side of the main shaft 4a, a main shaft side eccentric 4c and a 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 an intermediate shaft 4e that is provided between the main shaft side eccentric 4c and the sub shaft side eccentric 4d.

[0014]
A 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.

[0015]
Further, a 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.

[0016]
The compression mechanism 3 includes a first cylinder 8 on the main shaft 4a side and a second cylinder 9 on the sub shaft 4b side.

[0017]
The first cylinder 8 has a cylindrical through hole to which the first piston 11a 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.

[0018]
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 a partition plate 10, thus forming a compression chamber.

[0019]
The first cylinder 8 is fixed inside the hermetic vessel 1.

[0020]
The second cylinder 9 also has a cylindrical through hole to which a 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.

[0021]
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.

[0022]

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. [0023]
A bolt 12 depicted in Fig. 1 is a portion of a bolt that bolts and fixes the components from the outside of the main bearing 6 to the second cylinder 9 in the shaft direction.

[0024]
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.

[0025]
An accumulator 40 is provided adjacent to the hermetic vessel 1. A suction connecting pipe 21 and a suction connecting pipe 22 respectively connect the first cylinder 8 and the second cylinder 9 to the accumulator 40.

[0026]
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.

[0027]
Further, electric power is supplied to the motor 2 from the glass terminal 24 through the lead wire 25.

[0028]
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.

[0029]
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.

[0030]
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.

[0031]
In Embodiment 1, 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 peripheral side (the counter-shaft center side) relative to the periphery of the sub shaft 4b. [0032]
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. Accordingly, when attempting to assemble the first piston 11 a 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 11 b. 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 are enabled by forming the periphery of the sub shaft side eccentric 4d on the peripheral 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.

[0033]
Furthermore, in Embodiment 1, the shape of the crankshaft 4 (more specifically, the intermediate shaft 4e) is as illustrated in Figs. 2 to 4 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. The relationship between a bore 10a of the through hole of the partition plate 10, the outer diameters of the main shaft side eccentric 4c and the sub shaft side eccentric 4d, the outer diameter of the intermediate shaft 4e, and the position of the peripheries of the main shaft side eccentric 4c and the sub shaft side eccentric 4d on their counter-eccentric side will be described with reference to Figs. 2 to 4.

[0034]

As shown in Fig. 2, the bore 10a of the through hole of the partition plate 10 has a diameter Dmp. Further, this diameter Dmp is formed to be smaller than the outer diameter Dp of each of the sub shaft side eccentric 4d and the main shaft side eccentric 4c.
That is, Dmp < Dp. (1)

[0035]
Here, it is assumed that the partition plate 10 is composed of an integral component. Since the intermediate shaft 4e is disposed inside the through hole formed in the partition plate 10, for example, the sub shaft 4b and the sub shaft side eccentric 4d needs to be passed through the partition plate 10 in order to dispose the partition plate 10 to the position of the intermediate shaft 4e. However, in Embodiment 1, since Dmp < Dp, it is not possible to pass the sub shaft side eccentric 4d through the partition plate 10, and thus, it is not possible to dispose the partition plate 10 to the position of the intermediate shaft 4e. Accordingly, as shown in Fig. 4, in Embodiment 1, the partition plate is divided into two plates (a first divided plate 10b and a second divided plate 10c) by a section through the through hole. By disposing the first divided plate 10b and the second divided plate 10c so as to sandwich the intermediate shaft 4e, even if Dmp < Dp, the partition plate 10 can be disposed to the position of the intermediate shaft 4e. Note that the number of division of the partition plate 10 is, naturally, not limited to two but may be more than three, for example.

[0036]
That is, by divisionally forming the partition plate 10 in plural numbers, even if the sub shaft side eccentric 4d and the main shaft side eccentric 4c are each formed to have a large eccentricity, the bore 10a, which would become large in case of a partition plate 10 that is composed of an integral component, can be made small. If the bore of the partition plate 10 is small, a large distance between the periphery of each of the second piston 11b and the first piston 11a on the counter-eccentric side and the bore of the partition plate 10 can be obtained when the compression chambers are formed by fitting the second piston 11b and the first piston 11a to the sub shaft side eccentric 4d and the main shaft side eccentric 4c, respectively. Accordingly, a long sealing length can be obtained between the vicinity of the periphery of each of the second piston 11b and the first piston 11a on the counter-eccentric side, which is in a low-pressure state during the compression process of the refrigerant gas, and inside the bore 10a of the partition plate 10, which is in a high-pressure state by being in communication with a space with refrigerant gas that has been discharged from the compression chamber. Therefore, it is possible to reduce leaking of the refrigerant gas with high pressure from the inside of the bore 10a of the partition plate 10 with high pressure to the vicinity of the periphery of each of the second piston 11 b and the first piston 11 a on the counter-eccentric side with low pressure.

[0037]
As illustrated in Fig. 3 and the following Expression (2), in Embodiment 1, a radius Re of the periphery of the intermediate shaft 4e is larger than the distance Rp-e, which is the distance from the shaft center of the intermediate shaft 4e (that is, the shaft centers of the main shaft 4a and the sub shaft 4b) to the inner circumference of each of the second piston 11b and the first piston 11a on the counter-eccentric side. In other words, the radius Re of the periphery of the intermediate shaft 4e is larger than the distance Rp-e that is a distance from the shaft center of the intermediate shaft 4e to the periphery of each of the sub shaft side eccentric 4d and the main shaft side eccentric 4c on the counter-eccentric side.

Re > Rp-e (2)

That is, the periphery of the intermediate shaft 4e is formed on the peripheral side relative to the inner circumferences of each of the second piston 11b and the first piston 11 a on their counter-eccentric side. In other words, the periphery of the intermediate shaft 4e is formed on the peripheral side relative to each of the peripheries of the sub shaft side eccentric 4d and the main shaft side eccentric 4c on their counter-eccentric side.

Note that since the intermediate shaft 4e is disposed inside the bore 10a of the partition plate 10, the following holds true.
Re < Dmp/2 (3)

[0038]
By configuring the intermediate shaft 4e as above, the outer diameter of the intermediate shaft 4e can be made large and the rigidity of the crankshaft 4 can be made high. Accordingly, the deformation of the crankshaft 4 caused by gas load acting on the crankshaft 4 during the compression process of the refrigerant gas can be reduced, and, thus, the oil film in the main bearing 6 and the sub bearing 7 can be maintained in a favorable state and the reliability of the crankshaft 4 can be improved.

[0039]
Hence, in the 2-cylinder rotary compressor 100 that is structured as Embodiment 1, the eccentricity of each of the main shaft side eccentric 4c and the sub shaft side eccentric 4d is made large while maintaining the reliability of the crankshaft 4, and the displacement volume of the compression chamber can 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 11 a and the second piston 11b can be made further 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]
Incidentally, the 2-cylinder rotary compressor 100 according to Embodiment 1 can be further devised to reduce the length of the compression mechanism 3 in the shaft direction. For example, when attempting to assemble the first piston 11 a from the sub shaft 4b side, if the length of each of the first piston 11a and the second piston 11b in the shaft direction is not to be changed while reducing the length of the compression mechanism 3, 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.

[0043]
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 or 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.

[0044]

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 11a to the main shaft side eccentric 4c.

[0045]
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.

[0046]
Another method of reducing the length of the compression mechanism 3 in the shaft direction is, as illustrated in Fig. 5, 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 11 a-1 is formed with a bevel, step, or the like.

[0047]
Referring to Fig. 5, a process of assembling the first piston 11a to the main shaft side eccentric 4c will be described. (1) As shown in Fig. 5(a), the first piston 11 a 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) Next, as shown in Fig. 5(b), the first piston 1a is tilted (counterclockwise in Fig. 5(b)).

(3) Further, as shown in Fig. 5(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.

[0048]
Before describing the advantageous effect of providing the relief shapes 11a-1 to the two edges of the bore of the first piston 11a in the shaft direction, referring to Fig. 7, 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.

[0049]

The assembling process of the comparative example illustrated in Fig. 7 is as follows.

(1) As shown in Fig. 7(a), the first piston 11 a 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. 7(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. 7(c), the first piston 11a is fitted to the main shaft side eccentric 4c.

[0050]
Fig. 6 is a diagram comparing Embodiment 1 illustrated in Fig. 5, provided with the relief shapes 11 a-1 to the two edges of the bore of the first piston 11 a in the shaft direction, and the comparative example illustrated in Fig. 7. Fig. 6(a) is a diagram corresponding to Fig. 7(c), and Fig. 6(b) is a diagram corresponding to Fig. 5(d).

[0051]

The length of the intermediate shaft 4e, in the shaft direction, of the crankshaft 4 illustrated in Fig. 5, provided with the first piston 11 a having the relief shapes 11 a-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.

[0052]
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.

[0053]
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.

[0054]
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 11a 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.

[0055]
As above, in the 2-cylinder rotary compressor 100 configured as Embodiment 1, the diameter Dmp of the bore 10a of the partition plate 10 is formed to be smaller than the outer diameter Dp of each of the sub shaft side eccentric 4d and the main shaft side eccentric 4c, and the periphery of the intermediate shaft 4e is formed on the peripheral side relative to the inner circumferences of each of the second piston 11 b and the first piston 11a on their counter-eccentric side (in other words, on the peripheral side relative to the peripheries of each of the sub shaft side eccentric 4d and the main shaft side eccentric 4c on their counter-eccentric side). Accordingly, it will be possible to achieve high output and high efficiency of the 2-cylinder rotary compressor 100 while obtaining the reliability of the crankshaft 4.

[0056]
Note that 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. Further, the number of the compression chambers is not limited to two and, naturally, the invention may be applied to a multi-cylinder rotary compressor or a multi-stage rotary compressor that has three or more compression chambers. Furthermore, in Embodiment 1, although a high-pressure shell compressor, in which the discharged refrigerant inside of the hermetic vessel 1 is high in pressure, has been described as an example, it goes without saying that a low-pressure shell compressor, in which the suctioned refrigerant inside of the hermetic vessel 1 is low in pressure, may embody the invention.

[0057] Embodiment 2
In Embodiment 1, the relationship between the bore 10a of the partition plate 10, and the first piston 11a and the second piston 11b is not mentioned in particular. The bore 10a of the partition plate 10, and the first piston 11a and the second piston 11b may be formed such that the below relationship holds true, for example. It should be noted that, in Embodiment 2, items not specifically described are the same as those of Embodiment 1, and like functions and configurations are denoted by like reference signs.

[0058]
Fig. 8 is a diagram illustrating Embodiment 2 of the invention and is a longitudinal sectional view of a compression mechanism 3 of a 2-cyiinder rotary compressor 100.

As illustrated in Fig. 8, assuming that the distance from the shaft center of the intermediate shaft 4e to the inner circumference of the bore 10a of the partition plate 10 (that is, the radius of the bore 10a of the partition plate 10) is Rmp, the distance from the shaft center of the intermediate shaft 4e to the inner circumference of each of the second piston 11b and the first piston 11 a on the counter-eccentric side is Rp-e, and the distance from the shaft center of the intermediate shaft 4e to the periphery of each of the second piston 11b and the first piston 11a on the counter-eccentric side is Rr-e, then the following holds true.

Rmp > Rp-e (4)
Rmp < Rr-e (5)

That is, the inner circumference of each of the second piston 11b and the first piston 11a on the counter-eccentric side is disposed on the shaft center side of the intermediate shaft 4e relative to the bore 10a of the partition plate 10. Further, the periphery of each of the second piston 11b and the first piston 11 a on the counter-eccentric side is disposed on the peripheral side relative to the bore 10a of the partition plate 10.

[0059]
Note that the partition plate 10 is, similar to Embodiment 1, divided into plural divided plates. Further, the relationship between the diameter Dmp of the bore 10a of the partition plate 10 and the diameter Dp of the sub shaft side eccentric 4d and the main shaft side eccentric 4c, the relationship between the periphery of the intermediate shaft 4e and the inner circumference of each of the second piston 11b and the first piston 11a on the counter-eccentric side, and the relationship between the intermediate shaft 4e and the bore 10a of the partition plate 10 are similar to the Expressions (1) to (3) set forth in Embodiment 1.

[0060]
As described above, in the 2-cylinder rotary compressor 100 configured as such, by divisionally forming the partition plate 10 in plural numbers, even if the sub shaft side eccentric 4d and the main shaft side eccentric 4c are each formed to have a large eccentricity, the bore 10a, which would become large in case of a partition plate 10 that is composed of an integral component, can be made small. If the bore of the partition plate 10 is small, a large distance between the periphery of each of the second piston
11b and the first piston 11a on the counter-eccentric side and the bore of the partition plate 10 can be obtained when the compression chambers are formed by fitting the second piston 11b and the first piston 11a to the sub shaft side eccentric 4d and the main shaft side eccentric 4c, respectively. Accordingly, a long sealing length can be obtained between the vicinity of the periphery of each of the second piston 11 b and the first piston 11a on the counter-eccentric side, which is in a low-pressure state during the compression process of the refrigerant gas, and inside the bore 10a of the partition plate 10, which is in a high-pressure state by being in communication with a space with refrigerant gas that has been discharged from the compression chamber. Therefore, similar to Embodiment 1, it is possible to reduce leaking of the refrigerant gas with high pressure from the inside of the bore 10a of the partition plate 10 with high pressure to the vicinity of the periphery of each of the second piston 11b and the first piston 11 a on the counter-eccentric side with low pressure.

[0061]
Here, since the periphery of each of the second piston 11 b and the first piston 11a on the counter-eccentric side is disposed on the peripheral side relative to the bore 10a of the partition plate 10, a long sealing length can be obtained between the vicinity of the periphery of each of the second piston 11b and the first piston 11 a on the counter-eccentric side, which is in a low-pressure state during the compression process of the refrigerant gas, and inside the bore 10a of the partition plate 10, which is in a high-pressure state by being in communication with a space with refrigerant gas that has been discharged from the compression chamber. Therefore, it is possible to surely reduce leaking of the refrigerant gas with high pressure from the inside of the bore 10a of the partition plate 10 with high pressure to the vicinity of the periphery of each of the second piston 11b and the first piston 11a on the counter-eccentric side with low pressure. [0062]

Accordingly, in the 2-cylinder rotary compressor 100 configured as Embodiment 2 as well, it will be possible to achieve high output and high efficiency of the 2-cylinder rotary compressor 100 while obtaining the reliability of the crankshaft 4.

[Reference Signs List] [0063]
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; 7 sub bearing; 8 first cylinder; 9 second cylinder; 10 partition plate; 10a bore; 10b first divided plate; 10c second divided plate; 11a first piston; 11a-1 relief shape; 11b second piston; 12 bolt; 13 bolt; 20 oil supply hole; 21 suction connecting pipe; 22 suction connecting pipe; 23 discharge pipe; 24 glass terminal; 25 lead wire; 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 plurality of eccentrics that are formed to have a predetermined phase difference and that are provided between the main shaft and the sub shaft, and an intermediate shaft provided between adjacent eccentrics, the crankshaft being driven by the motor;
a plurality of cylinders each being formed with a cylindrical through hole, each of the cylinders being formed wrth a compression chamber in the through hole arranged with the corresponding one of the eccentrics; and

a partition plate being formed with a cylindrical through hole in which the intermediate shaft is disposed, the partition plate partitioning adjacent compression chambers of the cylinders, wherein

a periphery of the intermediate shaft is formed on a peripheral side relative to a periphery of each eccentric on a counter-eccentric side,

the partition plate is divided into plural plates by a section through the cylindrical through hole formed in the partition plate, and

a bore of the through hole of the partition plate is larger than an outer diameter of the intermediate shaft and is smaller than an outer diameter of each eccentric.

[Claim 2]

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 plurality of eccentrics that are formed to have a predetermined phase difference and that are provided between the main shaft and the sub shaft, and an intermediate shaft provided between adjacent eccentrics, the crankshaft being driven by the motor;
a plurality of pistons each being fitted to the corresponding one of the eccentrics;

a plurality of cylinders each being formed with a cylindrical through hole, each of the cylinders being formed with a compression chamber in the through hole arranged with the corresponding one of the eccentrics and the corresponding one of the pistons; and

a partition plate being formed with a cylindrical through hole in which the intermediate shaft is disposed, the partition plate partitioning adjacent compression chambers of the cylinders,
wherein

a periphery of the intermediate shaft is formed on a peripheral side relative to a periphery of each eccentric on a counter-eccentric side,

the partition plate is divided into plural plates by a section through the cylindrical through hole formed in the partition plate,

a bore of the through hole of the partition plate is larger than an outer diameter of the intermediate shaft and is smaller than an outer diameter of each eccentric, and

a periphery of each piston on a counter-eccentric side is formed on a peripheral side relative to the bore of the through hole of the partition plate.

[Claim 3]

The rotary compressor of any one of claim 1 to 2, wherein the crankshaft is formed of a material having a Young's modulus of 150 GPa or more.