JPH0642484A - Two cylinder type rotary compressor - Google Patents

Abstract

PURPOSE:To provide a two-cylinder type rotary compressor which has a compact shape and can obtain the refrigeration faculty nearly equal to 60Hz even with an electric power source frequency of 50Hz in a constant speed operation. CONSTITUTION:A rotary compressor is equipped with a compression mechanism part equipped with a crankshaft 3 having two eccentric parts which are directly connected with an electric motor and in eccentric in the opposite direction each other, two rollers 10a and 10b fitted into the eccentric part, and two cylinders 6 and 8 in which two rollers excentric-revolves, accompanied with the revolution of the crankshaft 3, and in the compression mechanism part, the elements such as a main bearing 5, first cylinder 6, partitioning plate 7, second cylinder 8, and a subbearing 9 are superposed from the electric motor side. A suction pipe 13 is connected with a subbearing 9, and a coolant flow passage communicating to the suction pipe 13 is formed in straight line form, and the length Lp of the suction pipe from a gas/liquid separator 12 in the reffiferation cycle to the connection with the subbearing 9 in a sealed container 1 is set so that the volume efficiency of the compressor in the operation with an electric power source efficiency of 50Hz becomes max.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-cylinder type rotary compressor used in a refrigerating cycle such as a refrigerator or an air conditioner, and particularly to a power source frequency of 50 Hz and 60 Hz.
The present invention relates to a compact, two-cylinder type rotary compressor suitable for obtaining a refrigerating capacity close to that during operation.

[0002]

2. Description of the Related Art As a structure of a general two-cylinder type rotary compressor, for example, a structure described in Japanese Patent Application Laid-Open No. 2-123295 is known. The structure of this conventional two-cylinder type rotary compressor will be described with reference to FIG. FIG. 3 is a vertical sectional view of a conventional two-cylinder type rotary compressor. Figure 3
In the two-cylinder type rotary compressor shown in (1), an electric motor section and a compression mechanism section are housed in a closed container 1. The electric motor part includes a stator 2 fixed by shrink fitting in the closed container 1.
And a rotor 4 fixed to the crankshaft 3.

Within the compression mechanism section, two sets of compression elements (hereinafter referred to as pump sections) are installed, of which the first pump section is the main bearing 5A for supporting the crankshaft 3, and the first pump section.
Cylinder 6A, partition plate 7A, eccentric portion 3a of crankshaft 3
It comprises a roller 10a fitted in and a vane (not shown) which reciprocates following the rotation of the roller 10a. The second pump portion includes the partition plate 7A, the second cylinder 8A, an auxiliary bearing 9A for supporting the crankshaft 3, a roller 10b fitted in the eccentric portion 3b of the crankshaft 3, and a roller 10.
The vanes (not shown) reciprocate following the rotation of b. These two sets of pump parts are fixed to the closed container 1 via a sheet metal frame 11.

Generally, in the case of the two-cylinder type rotary compressor of such a type, the two pumps inserted into the first pump section and the second pump section from the lower side of the gas-liquid separator 12 in the refrigeration cycle. The refrigerant gas is independently supplied by the suction pipes 13a and 13b. Therefore, it was relatively easy to utilize the pressure pulsation in each suction pipe to suck in a gas having a high density by the effect of inertia supercharging to improve the volumetric efficiency, that is, to increase the refrigerating capacity.

However, in such a conventional two-cylinder type rotary compressor, in order to connect two independent suction pipes to their respective pump parts, the first cylinder 6A has a size in which the suction pipes can be inserted. Also, it is necessary to increase the axial length of the second cylinder 8A. Therefore, the bearing span between the main bearing 5A and the sub bearing 9A becomes long, and the crankshaft is easily deformed by the compression pressure of the refrigerant gas, so that the bearing However, there is a problem in that one-sided contact or vibration around a touch due to deflection is likely to occur.

Therefore, in order to reduce the vibration and improve the reliability of the two-cylinder rotary compressor, one suction pipe is connected to a part of the compression mechanism portion such as the auxiliary bearing 9A, and two suction pipes are connected in the compression mechanism portion. A structure that branches into the pump section is preferable. Further, it is considered that the structure in which one suction pipe is branched in the pump (hereinafter, simply referred to as a branch suction structure) can manufacture the two-cylinder rotary compressor with a compact shape.

[0007]

However, in the case of a branched suction structure which has low vibration, high reliability and can be manufactured in a compact shape, it is necessary to improve the volumetric efficiency by utilizing the effect of inertia supercharging. It was very difficult to increase the refrigeration capacity. The reason is that in the case of the branched suction structure, the respective pump portions alternately suck the refrigerant gas with a phase difference of 180 °, so that the fluctuation of the volume velocity in the suction pipe becomes small. This phenomenon has also been reported in "The Pressure Pulsation of the Suction System in a Two-Cylinder Rotary Compressor" in the proceedings of the 26th Air Conditioning and Refrigeration Union Lecture Meeting (April 21, 22nd, Tokyo, April 1992). .

However, improving the refrigerating capacity by utilizing the effect of inertial supercharging or the like at a specific rotation speed is effective in using the two-cylinder type rotary compressor for a refrigerating cycle such as a refrigerator or an air conditioner. It was an important issue. This is because, in general, the compressor is often used at a constant rotation speed proportional to the power source frequency of 50 Hz and 60 Hz, and in that case, the refrigerating capacity is reduced by about 20% when operating at 50 Hz compared to when operating at 60 Hz. This is because there is a problem and using inertia supercharging is an effective means for compensating for this decrease.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to provide a compressor that operates at a constant rotation speed proportional to the power supply frequency.
An object of the present invention is to provide a compact two-cylinder type rotary compressor capable of obtaining a refrigerating capacity close to that at the time of operating at 60 Hz even with a power source frequency of 0 Hz.

[0010]

In order to achieve the above object, the structure of a two-cylinder type rotary compressor according to the present invention comprises a motor case and two compression elements each having the same stroke volume in a closed container. In the two-cylinder type rotary compressor in which the rotational force of the electric motor is transmitted to the compression mechanism section by the crankshaft and the refrigerant gas is alternately compressed by the two compression elements, Length L of one suction pipe that supplies refrigerant gas to the compression mechanism
p is a suction gas sonic velocity (m / s), fm is an operating frequency = 50 (Hz), and Vth is a stroke volume for one cylinder (m
³ ), when As is the suction pipe cross-sectional area (m ² ),

[Equation 2] It is set in the range that satisfies.

More specifically, an electric motor unit is directly connected to the electric motor in a hermetically sealed container, and the phases thereof are different from each other by 180 °.
A crankshaft having one eccentric portion, two rolling pistons fitted into the two eccentric portions, and two cylinders in which the two rolling pistons are eccentrically rotated as the crankshaft rotates. In a two-cylinder type rotary compressor including a compression mechanism section, the compression mechanism section has elements of a main bearing, a first cylinder, a partition plate, a second cylinder, and a sub-bearing superposed from the electric motor side. It is assumed that one suction pipe is connected to the auxiliary bearing on the side opposite to the electric motor, and the refrigerant flow path communicating with this suction pipe is
The length of the suction pipe from the gas-liquid separator in the refrigeration cycle until it is connected to the sub bearing in the closed container is formed linearly in each of the sub bearing, the second cylinder, the partition plate, and the first cylinder. , So that the volumetric efficiency of the compressor is maximized during operation at a power supply frequency of 50 Hz.

[0012]

In the suction inertia supercharging, it is considered that the pressure pulsation generated in the suction pipe increases the pressure when the cylinder is shut off, and as a result, the dense gas is sucked, so that the volumetric efficiency is improved. However, in the case of a configuration in which the refrigerant gas is guided into the pump section by one suction pipe and then the suction flow path is branched, it is not preferable to set the length of the suction pipe for a frequency of 50 Hz. This is because when pressure pulsation occurs in the pipe at a frequency of 50 Hz, one pump portion has a supercharging effect, but the other pump portion has a reverse effect, so that the overall volume efficiency is hardly improved. .

In the present invention of the branch type suction structure, in order to obtain the same effect of inertia supercharging in the two pump parts, the length of the suction pipe is set at a frequency twice as high as the target frequency. It was assumed that a certain correction would be performed by experiment, targeting 100 Hz. That is, the length of the suction pipe L that maximizes the pressure pulsation is calculated by the following equation (2).
I thought it would be preferable to set in.

[Equation 3]

Further, assuming that the suction chamber in each cylinder after branching is also a part of the suction pipe, if this pipe equivalent length is Lv, the suction pipe length Lp to be actually set is as follows. It is expressed by equation (3).

[Equation 4] Here, Lv is a value obtained by dividing the cylinder volume for one side by the cross-sectional area in the suction pipe, and in the present invention, it is set equally in two sets of pump parts.

As described above, according to the present invention, the two pump units are set so as to obtain substantially the same effect of inertia supercharging, and as a result of the experiment, fm = 50, that is, 50.
It was confirmed by experiments that it is highly effective to use the correction value C of 9 to 26 during Hz operation. That is, when the suction pipe length is set within the above range, 50H
The refrigerating capacity during z operation can be approximated during 60 Hz operation.

When the suction pipe is connected to the sub-bearing on the side opposite to the electric motor and the refrigerant flow path communicating with the suction pipe is formed in a straight line in the sub-bearing, the second cylinder, the partition plate and the first cylinder, The influence of the difference in the flow path length to each pump is small with respect to the entire suction pipe length, and the suction path to each cylinder and the suction resistance are set to be almost equal, so for two sets of pumps The same great supercharging effect can be obtained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a vertical sectional view of a two-cylinder rotary compressor according to one embodiment of the present invention, and FIG. 2 is a diagram showing a relationship between a suction pipe length Lp and a refrigerating capacity. In the figure,
Those having the same reference numerals as those in FIG. Figure 1
The 2-cylinder rotary compressor shown in FIG.
An electric motor unit and a compression mechanism unit including two pump units directly connected to the electric motor by a crankshaft are housed. The electric motor unit is composed of a stator 2 fixed to the closed container 1 by shrink fitting, and a rotor 4 fitted with a crankshaft 3.

The compression mechanism section has two rotary compression devices (pump sections), and the first pump section is composed of a main bearing 5, a first cylinder 6, and a partition plate 7, which support the crankshaft 3. The second pump part is the partition plate 7, the second pump part.
It is configured by a sub bearing 9 that supports the cylinder 8 and the crank shaft 3. The main bearing 5 is fixed to the closed container 1 by welding or the like.

The crankshafts 3 are eccentric in opposite directions, that is, the eccentric portions 3 are out of phase with each other by 180 °.
a, 3b, and rollers 10a, 10 relating to two rolling pistons fitted in these eccentric parts 3a, 3b
b is eccentrically rotated in the first cylinder 6 and the second cylinder 8 as the crankshaft 3 rotates. Further, in the first cylinder 6 and the second cylinder 8, vanes (not shown) that divide the inside of each cylinder into a suction side and a discharge side are installed in the same direction, and these vanes are installed in the roller 10a. , 10b reciprocally follows the rotation of the pumps 10b, so that the refrigerant gas is alternately compressed in each pump portion.

The refrigerant gas alternately compressed by the two sets of pump parts is silenced in the silencer formed by the auxiliary bearing 9 and the cover 14, and then discharged into the closed container 1. Further, in the refrigeration cycle, a gas-liquid separator 12 is provided in order to prevent the two-cylinder rotary compressor from sucking the liquid refrigerant. From the inside of the gas-liquid separator 12, the inside of the two-cylinder rotary compressor is provided. Lp up to the secondary bearing 9
The suction pipe 13 is installed. In the pump section,
A communication hole is provided in the partition plate 7 that partitions the two sets of pumps, and the refrigerant gas that has passed through the suction pipe 13 is linearly guided to each pump portion.

Here, the total length Lp of the suction pipe 13 is set so as to satisfy the above equation (3). However, since HFC134a was used as the refrigerant here, the sound velocity a of the suction gas was set to 163 m / s. The stroke volume Vth per cylinder of the compressor is

[Equation 5] Is. Also, the operating frequency f at which the refrigerating capacity should be improved
m is 50 Hz, and the correction value C is set to 18 as the result of the experiment. Therefore, the suction pipe length Lp is 350 mm.

As a result of operating the two-cylinder type rotary compressor under the above conditions with a commercial power source of 50 Hz and 60 Hz,
Compared with the case where inertia supercharging is not set, the same refrigerating capacity was obtained at 60 Hz, but at 50 Hz, setting the suction pipe length Lp to 350 mm resulted in about 9%.
The refrigerating capacity could be increased. Therefore, it was possible to solve the shortage of cooling power at 50 Hz, which is a problem in ordinary refrigerators and air conditioners.

Next, the suction pipe length Lp is set to 200 m.
Change from m to 400mm, 50Hz and 60
The influence on the refrigerating capacity when the two-cylinder type rotary compressor is operated by the commercial power source of Hz will be described with reference to FIG. In FIG. 2, the horizontal axis indicates the suction pipe length Lp (m
m), the vertical axis represents the cooling capacity (%), and the experimental results are shown. The white circles and solid lines show the cooling capacity at 50Hz power supply, and the black circles and broken lines show the cooling capacity at 60Hz power supply. is there.

From FIG. 2, it can be seen that in the case of 60 Hz operation, the effect of inertia supercharging is maximized when the suction pipe length Lp is 250 mm, and the refrigerating capacity is greatly improved with respect to 50 Hz operation. On the other hand, in the case of 50 Hz operation, 300
In the range of mm to 400 mm, there is an effect of inertia supercharging, and especially at 350 mm, the refrigerating capacity increases by about 9%.
50Hz
The most preferable result is obtained as a refrigerating machine using a constant speed compressor that operates in proportion to a commercial power supply of 60 Hz.

Based on the experimental results shown in FIG. 2, when the correction value C in the equation (3) is set in the range of 9 to 26, the suction pipe length Lp corresponds to the range of 300 mm to 400 mm. The effect of supercharging improves the refrigerating capacity during 50 Hz operation than usual. further,
When the suction pipe length Lp is set with the correction value C in Expression (3) being 18, it can be seen that the refrigerating capacity is maximized at the respective set lengths for both 50 Hz and 60 Hz operation. It has been confirmed that the above-mentioned correction value C exhibits the effect of inertial supercharging at the above-mentioned values even when the refrigerant used is changed and when the dimensions of each part of the compressor and the stroke volume are changed.

In this embodiment, the horizontal two-cylinder type rotary compressor has been described, but the same effect can be obtained even in the vertical type. Further, the connection portion of the suction pipe is not a sub-bearing but is connected to other pump parts such as the main bearing, the first cylinder, the partition plate, the second cylinder, and the like, and a similar effect can be obtained even if the structure is branched. be able to.

Further, in this embodiment, the case where the anti-compressor side of the suction pipe is inserted into the gas-liquid separator has been described, but it does not necessarily have a function of gas-liquid separation and the like, and the suction pipe is cut off. Any container may be used as long as it has a cross section with a shape significantly larger than the area. Even in that case, the present invention can be applied by treating the distance from the end surface of the suction pipe in the container to the cylinder inlet in the compressor as Lp.

[0028]

As described above in detail, according to the present invention, in a refrigeration cycle such as a refrigerator or an air conditioner, when the compressor is operated at a constant rotation speed proportional to the power supply frequency, 50 Hz. It is possible to provide a compact two-cylinder type rotary compressor capable of obtaining a refrigerating capacity close to that at the time of operation of 60 Hz even with the power supply frequency of.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a two-cylinder rotary compressor according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a suction pipe length Lp and a refrigerating capacity.

FIG. 3 is a vertical sectional view of a conventional two-cylinder type rotary compressor.

[Explanation of symbols]

 1 Airtight Container 2 Stator 3 Crankshaft 3a, 3b Eccentric Part 4 Rotor 5 Main Bearing 6 First Cylinder 7 Partition Plate 8 Second Cylinder 9 Secondary Bearing 10a, 10b Roller 12 Gas-Liquid Separator 13 Suction Pipe

Claims (3)

[Claims] 1. A hermetically sealed container is provided with an electric motor section and a compression mechanism section composed of two compression elements each having the same stroke volume, and the rotational force of the electric motor is transmitted to the compression mechanism section by a crankshaft. In a two-cylinder rotary compressor that alternately compresses the refrigerant gas with individual compression elements, the length Lp of one suction pipe that supplies the refrigerant gas to the compression mechanism section in the closed container is a suction gas velocity (M / s), fm is the operating frequency = 50
(Hz), Vth is the stroke volume for one cylinder (m ³ ),
When As is the suction pipe cross-sectional area (m ² ), A two-cylinder type rotary compressor characterized by being set in a range that satisfies the above condition. 2. A hermetically-sealed container, an electric motor part, a crankshaft having two eccentric parts directly connected to the electric motor and 180 ° out of phase with each other, and two crankshafts fitted into the two eccentric parts. In a two-cylinder type rotary compressor including a rolling piston and a compression mechanism section having two cylinders in which two rolling pistons are eccentrically rotated with the rotation of the crankshaft, the compression mechanism section includes: From the electric motor side, the main bearing, the first cylinder, the partition plate, the second cylinder, and the sub-bearing elements are superposed, and one suction pipe is connected to the sub-bearing on the anti-motor side and the suction is performed. The refrigerant flow path communicating with the pipe is
The length of the suction pipe, which is linearly formed on each of the second cylinder, the partition plate, and the first cylinder, and is connected from the gas-liquid separator in the refrigeration cycle to the auxiliary bearing in the closed container, is set to 50 Hz. A two-cylinder rotary compressor, which is set so that the volumetric efficiency of the compressor is maximized during operation at a power frequency. 3. The length Lp of the suction pipe from the gas-liquid separator to the auxiliary bearing in the closed container is calculated from the length L of the suction pipe where the pressure pulsation is maximum to the length equivalent to the suction pipe in the suction chamber of the pump. The two-cylinder rotary compressor according to claim 1 or 2, wherein the length is obtained by subtracting the length Lv.