WO2013057946A1 - Rotary compressor having two cylinders - Google Patents

Abstract

A rotary compressor having two cylinders (6a, 6b), and two compression elements (4a, 4b) arranged on either side of a partition plate (5), with these compression elements having rolling pistons (8) inside the cylinders (6), and a crankshaft (7) which is rotated by an electrical element (2) being inserted into a through-hole (5a) in the partition plate (5), with the rolling pistons (8) which are inserted into crankshaft eccentric parts (7a, 7b) rotating eccentrically when the crankshaft (7) rotates, thereby compressing an operating fluid within the cylinders (6) by means of the eccentric rotation of the rolling pistons (8). With this rotary compressor, the inner diameter φDc of the through-hole (5a) of the partition plate (5) is set so as to be larger than the outer diameter φDb of one crankshaft eccentric part (7b) and smaller than the outer diameter φDa of the other crankshaft eccentric part (7a), thereby minimizing the increase in the inner diameter φDc of the through-hole (5a) and providing a high-efficiency compressor (11a, 11b) for which leakage between the interior of the through-hole (5a) and the compression chambers (11a, 11b) can be suppressed, thereby improving the airtightness of the compression chambers (11a, 11b).

Description

Rotary compressor with two cylinders

The present invention relates to a rotary compressor having two cylinders used for an air conditioner, a refrigerator, a blower, a water heater, and the like.

In a refrigeration apparatus, an air conditioner, and the like, a compressor that sucks gas refrigerant evaporated by an evaporator, compresses it to a pressure necessary for condensation, and sends high-temperature and high-pressure gas refrigerant into a refrigerant circuit is used. . A rotary compressor is known as one of such compressors. Among them, the rotary compressor with two cylinders that constitute two compression chambers inside the compressor is being developed as a high-performance compressor because of its features such as low vibration, low noise and high speed operation. There is a need for a compact and higher volume compressor.

To increase the volume of the rotary compressor, a method of increasing the volume by increasing the height of the cylinder, or a method of increasing the eccentric amount of the crankshaft and designing a larger confining volume of the compression chamber is adopted. .
When the cylinder height is increased to increase the volume, it is necessary to increase the diameter of the crankshaft in order to cope with an increase in bearing load, leading to a reduction in compressor efficiency.

On the other hand, the method of increasing the eccentric amount of the crankshaft will be described for the case where it is used in a rotary compressor having two cylinders. The rotary compressor having two cylinders separates the two compression chambers by a partition plate, and the partition plate requires a through hole for passing the crankshaft. The size of the through hole is limited to a diameter into which the crankshaft can be inserted at the time of assembly, and generally has a diameter slightly larger than the diameter of the crankshaft eccentric portion.

Under such restrictions, a problem when the eccentric amount of the crankshaft is set large will be described with reference to FIG. FIG. 5A is an assembly diagram of the crankshaft, the rolling piston, and the partition plate when the amount of eccentricity is small. FIG. 5B is an assembly diagram when the eccentric amount is set large with the through holes of the partition plate kept the same.
By increasing the amount of eccentricity of the crankshaft eccentric portions 107a and 107b with respect to the crankshaft 107, the length of the seal portion 140 between the end surfaces of the rolling pistons 108a and 108b and the end surface of the partition plate 105 is reduced in the anti-eccentric direction. A minute gap is provided in the seal portion 140 in the height direction so that the rolling pistons 108a and 108b rotate eccentrically. In order to suppress leakage from the gap, it is desirable to make the length of the seal portion 140 as long as possible. However, as described above, the seal portion 140 is increased by increasing the amount of eccentricity of the crankshaft eccentric portions 107a and 107b. This causes a problem that the length of the refrigerant decreases, and leakage of the refrigerant through the seal portion 140 increases.

For example, a rotary compressor described in Patent Document 1 is shown in FIGS. FIG. 6 is a side sectional view of the rotary compressor, and FIG. 7 is an enlarged view of the main part.
As shown in FIGS. 6 and 7, in order to design the through hole 105a of the partition plate 105 to be small, the crankshaft 107 is divided into crankshaft eccentric parts 107a and 107b, and each unit is connected to a connecting part 141. As a result of connecting and assembling, the through hole 105a of the partition plate 105 has a smaller diameter than the crankshaft eccentric portion 107b. Thereby, the length of the above-mentioned seal part 140 can be set large, and the airtightness of the compression chambers 111a and 111b is improved.

JP 2005-337210 A

However, in the conventional configuration, since the crankshaft 107 is divided into units, it is difficult to ensure the coaxiality after assembly. In addition, since an intermediate bearing is newly provided in the through hole 105a of the partition plate 105, problems such as an increase in bearing loss have occurred. In addition, there is a problem of cost due to an increase in the number of parts.

The present invention solves the conventional problems and improves the airtightness of the compression chamber by reducing the diameter of the through hole of the partition plate and ensuring the length of the seal part without increasing the number of parts. The purpose is to provide a highly efficient compressor.

In order to solve the above conventional problems, in the rotary compressor having two cylinders of the present invention, two compression elements having a rolling piston are arranged adjacent to each other with a partition plate in the cylinder, and are rotated by an electric element. The crankshaft is inserted into the through hole of the partition plate, and the crankshaft rotates to cause the rolling piston inserted into the eccentric portion of the crankshaft to rotate eccentrically, and the working fluid in the cylinder is rotated to eccentrically rotate the rolling piston. In the rotary compressor having two cylinders to be compressed, the inner diameter φDc of the through hole is larger than the outer diameter φDb of one of the crankshaft eccentric portions, and is larger than the outer diameter φDa of the other crankshaft eccentric portion. small.
Usually, the outer diameter of the crankshaft eccentric portion needs to have a sufficient bearing resistance against the load received from the working fluid compressed by the rolling piston by the compression element. Therefore, in order to achieve a higher volume, it is necessary to increase the diameter of the crankshaft eccentric part. However, when the diameters of both crankshaft eccentric parts are increased, the partition plate is The inner diameter of the through hole increases as the diameter of the crankshaft eccentric portion increases, and the length of the seal portion formed by the rolling piston end face and the partition plate inevitably decreases.
In the present invention, the outer diameter φDa of the other crankshaft eccentric portion is configured to be larger than the inner diameter of the through hole of the partition plate. It is possible to ensure the length of the seal portion as much as possible without increasing the inner diameter of the through hole of the partition plate.

According to the present invention, even if the volume of the compressor is set to be large, the seal portion between the partition plate and the rolling piston end face can be lengthened, thereby improving the hermeticity of the compression chamber and providing a highly efficient rotary cylinder having two cylinders. A compressor can be realized.

The longitudinal cross-sectional view of the rotary compressor which has two cylinders in embodiment of this invention The top view of the compression element in embodiment of this invention Explanatory drawing which shows the positional relationship at the time of the assembly of the crankshaft, partition plate, and rolling piston in embodiment of this invention Explanatory drawing which shows the positional relationship at the time of the assembly of the crankshaft in a prior art, a partition plate, and a rolling piston. (A) Assembly drawing of main part of compression mechanism with reduced eccentricity in the prior art (b) Assembly drawing of main part of compression mechanism with increased eccentricity in the prior art Side view of a rotary compressor with two cylinders in the prior art Enlarged view of the main part

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Electric element 3 Crankshaft 4 Compression element 5 Partition plate 5a Through-hole 6 Cylinder 7 Crankshaft 7a The other crankshaft eccentric part 7b One crankshaft eccentric part 7c Crankshaft main shaft part 7d Crankshaft subshaft part 8 Rolling Piston 11a, 11b Compression chamber 12 Accumulator 20 Oil storage part 22a, 22b Vane

In the rotary compressor of the first invention, two compression elements each having a rolling piston in two cylinders are arranged adjacent to each other with a partition plate interposed therebetween, and a crankshaft rotated by the electric element is inserted through a through hole of the partition plate, In a rotary compressor having two cylinders in which the rolling piston inserted into the eccentric part of the crankshaft rotates eccentrically by rotating the shaft and compresses the working fluid in the cylinder by the eccentric rotation of the rolling piston. φDc is larger than the outer diameter φDb of one crankshaft eccentric portion and smaller than the outer diameter φDa of the other crankshaft eccentric portion. Since the outer diameter φDa of the other crankshaft eccentric portion is larger than the inner diameter of the through hole of the partition plate, it is possible to ensure a sufficient shaft diameter for the load received from the working fluid to be compressed in the compression element. it can. In addition, since the inner diameter of the through hole of the partition plate is not enlarged even when the amount of eccentricity is increased, the length of the seal portion can be ensured as much as possible.

In the second aspect of the invention, in particular, in the rotary compressor having two cylinders of the first aspect of the invention, the axial height Hb of one crankshaft eccentric part is the axial height Ha of the other crankshaft eccentric part. Higher than that. Even when the required bearing strength cannot be ensured only by the shaft diameter of the eccentric portion, the bearing strength can improve the bearing strength, and the expansion of the inner diameter of the through hole of the partition plate can be minimized.

In a third aspect of the invention, in particular, in the rotary compressor having two cylinders of the first or second aspect of the invention, the compression chamber volume of the compression element compressed at one crankshaft eccentric portion is the compression chamber of the other compression element. It is set smaller than the volume. In the compression element where the expansion of the shaft diameter of the eccentric part leads to the expansion of the inner diameter of the through hole of the partition plate, reliability is ensured by making the compression chamber volume smaller than the other compression element and reducing the bearing load itself of the eccentric part. It becomes possible to do.

In the fourth aspect of the invention, in particular, in the rotary compressor having the two cylinders of the first to third aspects of the invention, the compression element that compresses at the eccentric part of the other crankshaft is used as the main bearing that mainly supports the crankshaft. It is arranged closer. Therefore, since the compression element having a larger load can be pivotally supported near the bearing, the moment applied to the bearing is reduced, and high reliability can be ensured in realizing the present invention. The main bearing that is mainly supported here means a bearing having the largest product of the square of the bearing diameter and the bearing length when the crankshaft itself is supported by a plurality of bearings, and has two cylinders. In general, the rotary compressor is provided on the electric element side.

In the fifth aspect of the invention, in particular, in the rotary compressor having the two cylinders of the first to fourth aspects of the invention, the through hole is filled with lubricating oil or working fluid to which the discharge pressure of the working fluid compressed by the compression element is applied. It is what has been. By configuring the inside of the compression chamber to be substantially the same pressure as the discharge pressure, it becomes easy to supply the lubricating oil to the sliding portion, so that the reliability of the compressor is excellent. However, when a rotary compressor having two cylinders is filled with high-pressure lubricating oil or working fluid inside the through-hole, there is a concern that it may leak into the compression chamber due to a pressure difference. On the other hand, when the inside of the through hole of the partition plate is filled with low-pressure lubricating oil or working fluid, the compressed working fluid may leak from the compression chamber during compression and discharge through the seal portion. There is no pressure difference from the compression chamber during suction, and the time for holding the pressure difference through the seal portion is shortened. That is, the effect of securing the length of the seal portion according to the present invention is more remarkable when the inside of the through hole is filled with high-pressure lubricating oil or the like.

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

(Embodiment)
FIG. 1 is a longitudinal sectional view of a rotary compressor having two cylinders according to an embodiment of the present invention, and FIG. 2 is a plan view of a compression element.

1, the electric element 2 and the compression element 4 are accommodated in the sealed container 1. The electric element 2 rotates the crankshaft 7, and the compression element 4 is driven by the crankshaft 7.

The compression element 4 is composed of compression elements 4a and 4b, each performing a compression operation independently. The compression element 4a includes a cylinder 6a that forms a cylindrical space, and a rolling piston 8a that is disposed in the cylinder 6a. The compression element 4b has a cylinder 6b that forms a cylindrical space, and a rolling piston 8b that is disposed in the cylinder 6b.
The crankshaft 7 is provided with crankshaft eccentric portions 7a and 7b. The partition plate 5 is disposed between the two compression elements 4a and 4b. A main bearing 31 is disposed on the electric element 2 side of the compression element 4a. The main bearing 31 forms an upper end plate together with a bearing portion that supports the crankshaft main shaft portion 7c. The upper end plate closes the electric element 2 side of the compression element 4a. A sub bearing 32 is disposed on the oil storage section 20 side of the compression element 4b. The auxiliary bearing 32 forms a lower end plate together with a bearing portion that supports the crankshaft auxiliary shaft portion 7d. The lower end plate closes the oil storage section 20 side of the compression element 4b.

A cylinder 6 a is disposed on the upper surface of the partition plate 5, and a cylinder 6 b is disposed on the lower surface of the partition plate 5. The other crankshaft eccentric portion 7a is accommodated in the cylinder 6a, and the other crankshaft eccentric portion 7b is accommodated in the cylinder 6b.
The crankshaft eccentric portions 7 a and 7 b are configured integrally with the crankshaft 7. A rolling piston 8a is rotatably mounted on the other crankshaft eccentric portion 7a, and a rolling piston 8b is rotatably mounted on one crankshaft eccentric portion 7b.

As shown in FIG. 2, a vane groove 21a is formed in the cylinder 6a, and a vane groove 21b is formed in the cylinder 6b. A vane 22a is slidably disposed in the vane groove 21a, and a vane 22b is slidably disposed in the vane groove 21b. A back pressure is applied to the vane 22a, and the vane 22a always abuts against the rolling piston 8a. A back pressure is applied to the vane 22b, and the vane 22b always abuts against the rolling piston 8b. The cylinder 6a is provided with a suction passage 9a, and the cylinder 6b is provided with a suction passage 9b. A suction pipe 10a is connected to the suction passage 9a, and a suction pipe 10b is connected to the suction passage 9b. The suction passage 9a and the suction passage 9a are independent from each other, and the suction pipe 10a and the suction pipe 10b are independent from each other. The suction pipe 10a communicates with the compression chamber 11a through the suction passage 9a, and the suction pipe 10b communicates with the compression chamber 11b through the suction passage 9b.

Further, in order to prevent liquid compression in the compression chambers 11a and 11b, an accumulator 12 is provided in the suction pipes 10a and 10b. The accumulator 12 gas-liquid separates the refrigerant and guides only the refrigerant gas to the suction pipes 10a and 10b. In the accumulator 12, a refrigerant gas introduction pipe 14 is connected to the upper part of a cylindrical case 13, and two refrigerant gas outlet pipes 15a and 15b are connected to the lower part. One ends of the refrigerant gas outlet pipes 15 a and 15 b are connected to the suction pipes 10 a and 10 b, and the other ends of the refrigerant gas outlet pipes 15 a and 15 b extend to the upper part of the internal space of the case 13.

When the crankshaft 7 is rotated by the electric element 2, the crankshaft eccentric portions 7a and 7b are eccentrically rotated in the cylinders 6a and 6b, and the rolling pistons 8a and 8b are rotated while being in contact with the vanes 22a and 22b. The suction and compression of the refrigerant gas are repeated in both cylinders 6a and 6b at a period in which the rolling piston 8a and the rolling piston 8b are shifted by a half rotation. The low-pressure refrigerant sucked from the refrigerant gas introduction pipe 14 is gas-liquid separated in the case 13, and the refrigerant gas separated from the liquid refrigerant is refrigerant gas outlet pipes 15a and 15b, suction pipes 10a and 10b, and a suction passage 9a. 9b and is sucked into the compression chambers 11a and 11b.

The lubricating oil in the oil storage section 20 at the bottom of the closed container 1 is supplied from the lower end of the crankshaft countershaft section 7d to the through hole 5a via the inside of the crankshaft 7, and the partition plate 5 and the rolling piston 8a, The region surrounded by 8b and the crankshaft 7 is filled.

The operation and action of the rotary compressor having two cylinders configured as described above will be described below.

FIG. 3 is a side view of the main part showing the positional relationship during assembly of the crankshaft, partition plate, and rolling piston of the rotary compressor in the embodiment of the present invention.

At the time of assembly, the partition plate 5 is inserted from the crankshaft countershaft portion 7d side, and is disposed between one crankshaft eccentric portion 7a and the other crankshaft eccentric portion 7b through one crankshaft eccentric portion 7b. . Therefore, it is necessary to set the inner diameter φDc of the through hole 5a of the partition plate 5 to be larger than the outer diameter φDb of the one crankshaft eccentric portion 7b.

On the other hand, in the embodiment of the present invention, the outer diameter φDa of the other crankshaft eccentric portion 7a is set larger than the inner diameter φDc of the through hole 5a, and the partition plate 5 is inserted from the crankshaft main shaft portion 7c side. It is not possible. Thus, by setting the outer diameter φDa of the crankshaft main shaft portion 7a to be large, it is possible to improve the proof strength against the load received from the rolling piston 8a during compression, and it is high even if the volume of the compression element 4a is large. Reliability can be realized.

In FIG. 3, the through hole 5a is filled with lubricating oil. A discharge pressure is applied to the lubricating oil in the through hole 5a. The through hole 5a may be filled with the working fluid. Also in this case, a discharge pressure is applied to the working fluid in the through hole 5a. A pressure difference between the compression chamber 11a and the compression chamber 11b is secured by the seal portion 40 formed by the end surface of the partition plate 5 and the end surfaces of the rolling pistons 8a and 8b. However, the seal portion 40 is provided with a minute gap in the height direction so that the rolling piston 8 can rotate eccentrically, and the length of the seal portion 40 is required to suppress leakage from the gap. It is desirable to make (the length in the radial direction) as long as possible. In the embodiment of the present invention, the inner diameter φDc of the through hole 5a can be reduced by setting the outer diameter φDb of one crankshaft eccentric portion 7b to be small. In addition, since the radial length of the rolling piston 8b can be increased by the reduced length of the outer diameter φDb of one crankshaft eccentric portion 7b in the radial direction, the seal portion 40 can be lengthened in the radial direction, and the compression chamber can be extended from the through hole 5a. It is possible to prevent the lubricating oil from leaking into 11a and 11b.

As a comparative example, FIG. 4 shows an assembly diagram when the outer diameter φDb of one crankshaft eccentric portion 7b is set to be the same as the outer diameter φDa of the other crankshaft eccentric portion 7a.
As the outer diameter φDb of one crankshaft eccentric portion 7b that passes through the through hole 5a increases, the inner diameter φDc of the through hole 5a increases, so the outer diameter of the rolling piston 8b and the eccentric amount of the one crankshaft eccentric portion 7b are as follows. Although it is the same, it turns out that the length of the seal | sticker part 40 becomes short and the leak from the through-hole 5a to the compression chambers 11a and 11b will increase.

Thus, the outer diameter φDb of one crankshaft eccentric portion 7b inserted into the through hole 5a of the partition plate 5 during assembly is set smaller than the outer diameter φDa of the other crankshaft eccentric portion 7a, and the inner diameter of the through hole 5a is set. The length of the seal portion 40 can be increased by keeping φDc large enough to allow the one of the crankshaft eccentric portions 7b having the smaller outer diameter to pass, and the high pressure lubricating oil can be prevented from entering the compression chamber 11. ing.

In order to compensate for a decrease in bearing strength due to the outer diameter φDb of one crankshaft eccentric portion 7b being smaller than the outer diameter φDa of the other crankshaft eccentric portion 7a, as shown in FIG. The shaft height Hb of the eccentric portion 7b may be set higher than the shaft height Ha of the other crankshaft eccentric portion 7a. Thereby, even when the required bearing strength cannot be ensured only by the shaft diameter of one crankshaft eccentric portion 7b, the bearing strength can be improved by the bearing height Hb, and the inner diameter φDc of the through hole 5a of the partition plate 5 can be increased. Expansion can be kept to a minimum.

Moreover, you may set the compression chamber volume of the compression element 4b smaller than the compression chamber volume of the compression element 4a. The compression chamber volume of the compression element 4b is the volume of the compression chamber 11a formed by the cylinder 6a, the rolling piston 8a, the upper end plate of the main bearing 31, and the partition plate 5, and the compression chamber volume of the compression element 4a is the cylinder 6b. , The volume of the compression chamber 11b formed by the rolling piston 8b, the lower end plate of the auxiliary bearing 32, and the partition plate 5.
Thereby, the expansion of the shaft diameter of one crankshaft eccentric part 7b caused the expansion of the inner diameter φDc of the through hole 5a of the partition plate 5, but the compression of the compression element 4b rather than the compression chamber 11b of the compression element 4a. It is possible to ensure reliability by reducing the volume of the chamber 11a and reducing the bearing load of one crankshaft eccentric portion 7b.

Further, the compression element 4a to be compressed by the other crankshaft eccentric portion 7a may be disposed near the main bearing 31 that mainly supports the crankshaft 7. Since the compression element 4a having a larger load can be pivotally supported near the main bearing 31, the moment applied to the main bearing 31 is reduced, and high reliability can be ensured in realizing the present invention.

In the present invention, a rotary compressor having two cylinders is described. However, a rotary compressor having two or more cylinders can achieve the effect by performing the same configuration. It is.

As described above, the rotary compressor having two cylinders according to the present invention improves the airtightness of the compression chamber by suppressing leakage through the partition plate and the seal portion between the end faces of the rolling piston. High efficiency can be achieved. Thus, in addition to the air-conditioning compressor using HFC refrigerant such, they can be applied to applications such as air conditioning and heat pump water heater using CO ₂ as a natural refrigerant.

Claims (5)

Two compression elements having a rolling piston in the cylinder are arranged adjacent to each other with a partition plate in between,
A crankshaft rotated by an electric element is inserted through the through hole of the partition plate,
When the crankshaft rotates, the rolling piston inserted into the crankshaft eccentric part rotates eccentrically,
In the rotary compressor having two cylinders for compressing the working fluid in the cylinder by the eccentric rotation of the rolling piston,
An internal diameter φDc of the through hole is larger than an outer diameter φDb of one crankshaft eccentric portion and smaller than an outer diameter φDa of the other crankshaft eccentric portion. Machine. 2. The rotary compression with two cylinders according to claim 1, wherein an axial height Hb of one crankshaft eccentric portion is higher than an axial height Ha of the other crankshaft eccentric portion. Machine. The compression chamber volume of the compression element compressed by one of the crankshaft eccentric portions is set smaller than the compression chamber volume of the other compression element. Rotary compressor with cylinder. 4. The compression element according to claim 1, wherein the compression element that compresses the other crankshaft eccentric portion is disposed closer to a main bearing that mainly supports the crankshaft. 5. Rotary compressor with two cylinders. The said through-hole is filled with the lubricating oil or the said working fluid to which the discharge pressure of the said working fluid compressed by the said compression element is added, The 2 in any one of Claims 1-4 characterized by the above-mentioned. Rotary compressor with two cylinders.

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