JPH04203489A - Multi-cylinder rotary compressor - Google Patents

Abstract

PURPOSE:To control volume precisely by providing gas injection circuits to return gas refrigerant into compression chambers of compression elements, and opening injection holes on the respective compression chambers. CONSTITUTION:A compression chamber 15a of an upper cylinder 4 is separated from a compression chamber 15b of a lower cylinder 5 with a separation plate 6, and respective injection holes 26a, 26b and pipes 27a, 27b are provided independently. And independent injection circuits are connected to injection pipes 27a, 27b from a gas-liquid separator respectively. Thereby as injection holes are provided for respective compression elements, the operation of respective elements can be combined to enable precise volume control of medium pressure or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application + IFJ This invention relates to capacity control of a multi-cylinder rotary compressor.

[Prior art 7] Figures 5 and 6 are cross-sectional views showing a conventional multi-cylinder rotary compressor disclosed in, for example, Japanese Utility Model Application Publication No. 186/1982.
In the figure, (■) is a closed container.

An electric element (2) and a lower compression element (3) are housed in the upper part. In the compression element (3), (4) and (5) are an upper cylinder and a lower cylinder separated by a partition plate (6), (
7) and (8) are the upper and lower bearings that close the open ends of both cylinders (4) and (5), (9) is the crankshaft supported by these bearings (7) and (8), 1
0a,).

(10b) is the eccentric portion (lla) of the crankshaft (9)
, (11b) is attached to the cylinder <4): (5
) a rolling piston rotating within (12a);
(12b) is a vane groove, cylinders (4), (5)
formed in the axial and radial direction of (13a),
(13b) is this vane groove (12a).

The vanes are housed in (12b) via springs (14a) and (14b), respectively, and the spring (14a)
, (14b) and the rolling piston (
loa) and (10b) so as to be in constant elastic contact with the outer circumferential surfaces. (15) is a compression chamber, which includes the cylinders (4), (5) and the rolling piston (10), respectively.
a), (10b) and vane (13a), (13b)
It is formed by (16) shows the high pressure side of the compression chamber C, and (17) also shows the low pressure side.

(18) is a discharge boat opening into the compression chamber (15);
19) communicates with this discharge boat (18), and the cylinder (
4).

(5) a valve chamber penetrating in the axial direction; (20) a discharge valve made of an elastic thin plate that opens and closes the discharge boat (18);
1) is a valve holder that regulates the stroke of this discharge valve (20).

(22) connects the discharge valve (20) and valve holder (21) to the valve chamber (
19) Support bolt to be fixed inside, (23) is cylinder, (4).

(5) is a gas suction pipe that leads refrigerant gas from the external piping to the low pressure side (17) of the compression chamber (15); (24) is the lubricating oil stored at the bottom of the closed container (1); (25) is the gas discharge pipe.

Next, the operation will be explained.

The electric element (2) drives the rolling piston (10
a) and (10b) rotate in the direction of the arrow, refrigerant gas flows from the gas suction pipe (23) to the low pressure side (1) of the compression chamber (15).
7), is compressed on the high pressure side (16), and is discharged from the discharge boat (18). At this time, the vane (13a
).

(13b) is the rolling piston (10a), (lo
b) vane groove (13a), (13
b) Inside is 1jl! Sliding.

Such rotary compressors are not limited to multiple cylinders;
In order to improve its performance, as shown in FIG. 7, in the refrigeration circuit, after the condenser (32), a refrigerant pressure reducing means (33)
(34) is formed into two stages and connected to the evaporator, and a gas-liquid separator (35) is provided between the two stages of pressure reduction means to separate the gas refrigerant and liquid refrigerant. through the means to the evaporator (36), the gas refrigerant is passed through the gas injection circuit (37) to the compression element (3) of the compressor (38).
) is known as a gas injection cycle.

The circuit is explained using the Mollier diagram in FIG. 8. In the case of cooling, the cooling effect increases by /i in FIG. 1, and in the case of heating, the heating effect increases by the gas injection flow rate g. Further, the capacity control rate indicating the rate of increase is determined by the intermediate pressure Pm.

Regarding the specific structure, see Figure 9 and Figure 1 for the single cylinder rotary compressor shown in Japanese Patent Publication No. 58-54274.
This will be explained using Figure 0.

In the figure, (26) is the refrigerant injection hole into the compression chamber (15) opened in one of the bearing plates.

This is connected to the gas-liquid separator of the refrigeration circuit through a pipe (28).

Next, let me explain the injection operation.

The injection hole (26) is opened and closed on the side surface of the rolling piston (10) during one revolution of the crankshaft (9).

Therefore, with respect to the refrigerant during the compression process, the refrigerant at the intermediate pressure Pm is injected into the compression chamber (15) from the injection hole (26) during a certain period during the compression process.

[Problems to be Solved by the Invention] A rotary compressor with a conventional gas injection mechanism is configured as described above, and the intermediate pressure Pm that determines the capacity increase rate is determined by the pressure of the injection hole provided in the compressor. It is determined as a matching point between the injection flow rate characteristics determined by size and position and the amount of gas generated within the gas-liquid separator. Therefore, there was a problem in that the capacity increase rate was 1 point, making it difficult to perform fine capacity control operation according to the load.

This invention was made to solve the above-mentioned problems, and its purpose is to obtain a multi-cylinder rotary compressor that can perform finer capacity control operation.

[Means for Solving the Problems] In the invention according to claim 1, an injection hole is formed for each compression element.

According to the second aspect of the invention, the injection holes are formed at different positions or sizes for each compression element.

[Function] The invention as claimed in claim 1 provides an injection hole for each compression element, and by combining injection operations for each compression element, it is possible to control the intermediate pressure at multiple points and the capacity at multiple stages. have a rate.

According to the second aspect of the invention, the injection holes are formed at different positions or sizes for each compression element, and by combining injection operations with unique flow characteristics, more fine capacity control is achieved.

[Example] An example of the present invention will be described below with reference to FIGS. 1 to 4.

In the figure, the upper cylinder (4) is separated by a partition plate (6).
), each compression chamber (15a) of the lower cylinder (5), (1
5b) are independently provided with injection holes (26a), (26b) bored in the upper bearing or lower bearing (8), and pipes (27a), (27b) communicating with the injection holes (26a), (26b). .

In addition, mutually independent injection circuits (37a) and (37b) are connected to the gas-liquid separator (35) provided between the two-stage pressure reducing means (33) and (34), respectively, with regulating valves (
Injection (28a), (28b)
7a) and (27b).

Next, the operation will be explained.

By opening and closing the regulating valves (28a) and (28b) during compressor operation, the upper and lower compression chambers (15a) and (15b
) from the gas-liquid separator (35) to the gas injection circuit (37a), (37b) and the regulating valve (28a), (
28b), and the refrigerant is injected from the injection hole communicating with the injection pipe.

When these regulating valves (28a) and (28b) are opened and closed, the flow rate characteristics of the refrigerant to be injected change, so the matching point with the amount of gas generated in the gas-liquid separator moves, resulting in the intermediate pressure Pm and, ultimately, the capacity. The control rate also changes. FIG. 4 shows the changes on the Mollier diagram at that time. This shows that there are intermediate pressures for the number of combinations of opening and closing of the regulating valve, and thus a plurality of capacity control steps. In Figure 1, Ps is the suction pressure of the compressor, and Pd is the discharge pressure.

In addition, in the above embodiment, the injection holes (26a) and (26b) of each compression element were opened at the same position and with the same size, but the injection holes were provided at different positions for each compression element. Good too.

Furthermore, the sizes of the injection holes (26a) and (26b) may be changed for each compression element.

By providing each compression element with a different position or size, each compression element has its own unique flow rate characteristics, so by using them in combination, it becomes possible to have a larger number of capacity control steps, allowing for finer capacity control. A controllable multi-cylinder rotary compressor can be obtained.

[Effects of the Invention] According to the invention as set forth in claim 1, since the injection hole is formed for each compression element, the injection operation can be combined for each compression element.
Intermediate pressure at multiple points.

As a result, it is possible to obtain a capacity control rate of multiple steps.

According to the invention as claimed in claim 2, by forming the injection holes at different positions or sizes for each compression element, it is possible to combine injection operations having unique flow rate characteristics, so that finer capacity control is possible. It has the effect of getting what is possible.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a multi-cylinder rotary compressor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a cross-sectional view of the multi-cylinder rotary compressor shown in FIG. 1. FIG. 4 is a Mollier diagram of FIG. 3, FIG. 5 is a sectional view of a conventional multi-cylinder rotary compressor, and FIG. 6 is a Vl-Vl diagram of FIG. 5. The sectional view and FIG. 7 are refrigeration circuit diagrams equipped with an injection mechanism using a conventional rotary compressor. Fig. 8 is the Mollier diagram of Fig. 7, Fig. 9 is a sectional view of the main part showing a conventional single cylinder rotary compressor, and Fig. 10 is the x of Fig. 9.
-X sectional view. (1) is a closed container, (2) is an electric element, (3) is a compression element, (15) is a compression chamber, (26) is an injection hole, (35) is a gas-liquid separator, (37) is a gas injection circuit. In Figure 1, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) An electric element in a sealed container, a plurality of compression elements driven by the electric element, a gas injection circuit that returns gas refrigerant from a gas-liquid separator in a refrigeration circuit to a compression chamber in the compression element, and a compression element. What is claimed is: 1. A multi-cylinder rotary compressor having an injection hole opened indoors, characterized in that an injection hole is formed for each compression element. (2) An electric element in a sealed container, a plurality of compression elements driven by the electric element, a gas injection circuit that returns gas refrigerant from a gas-liquid separator in the refrigeration circuit to a compression chamber in the compression element, and a compression element. What is claimed is: 1. A multi-cylinder rotary compressor equipped with an injection hole opened indoors, characterized in that the injection hole is formed at a different position or size for each compression element.