JPS62111188A - Variable displacement rotary compressor - Google Patents

Abstract

PURPOSE:To control delivery volume with no decrease of compression efficiency, by returning refrigerant gas, given compression work, to an expansion stroke before a suction stroke. CONSTITUTION:Refrigerant gas, given compression work in an operative chamber 16, is returned to the second suction port 18, formed in a part with the operative chamber 16 serving for an expansion stroke, through a bypass passage 21. And while a vane 15 reaches the first suction port 17, being a main suction port of the operative chamber 16, the bypass flowing refrigerant gas acts on the vane 15 with the above obtained compression work serving as expansion work. In this way, the compression work, given to the refrigerant gas allowed to bypass flow for controlling delivery volume, can be effectively recovered as driving force, and the delivery volume can be controlled with no decrease of compression efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotary compressor suitable for use as a refrigerant compressor in automobile air conditioners and the like.

2. Description of the Related Art In recent years, compressors with variable discharge capacity have been proposed in order to achieve both cooling performance and reduction in compressor power consumption.

A conventional variable displacement rotary compressor of this type has a structure as shown in FIG.

That is, a bypass passage 6 is provided that communicates the working chamber 4 with the suction passage 5 during the compression stroke in which the volume of the elevating chamber 4 defined by the cylinder 1, rotor 2, and vane 3 decreases. Opening/closing valve 7 that opens and closes 6
When the on-off valve 7 is closed, the entire amount of refrigerant sucked into the working chamber 4 through the suction port 8 is compressed and flows through the discharge port 9.
In the open state, a part of the refrigerant sucked into the working chamber 4 from the suction port 8 returns to the suction passage 5 via the bypass passage 6, so that the discharge capacity of the compressor can be increased or decreased by opening or closing the bypass passage 6. It has become.

(For example, Japanese Unexamined Patent Publication No. 57-198387) Problems to be Solved by the Invention However, with such a structure, the refrigerant sucked into the working chamber 4 is compressed to some extent and flows from the bypass passage 6 to the suction passage. As the refrigerant flows into the suction passage S, the compression work given to the refrigerant becomes a loss, which deteriorates the efficiency of the compressor.Furthermore, the refrigerant in the suction passage S is heated by this loss, and as a result, the temperature of the discharged refrigerant decreases. There is a problem in that this causes the compressor to rise and deteriorates the durability of the compressor, refrigerating machine oil, refrigerant piping rubber hose, etc.

Means for Solving the Problems In order to solve the above problems, the present invention utilizes a portion of the suction stroke in which the volume of the working chamber increases to act as an expander that can recover compression work from the returning refrigerant. The first suction port communicates with the suction chamber and opens into the working chamber at the end of the suction stroke, and the first suction port communicates with the suction chamber through a suction passage and operates near the small gap between the rotor and cylinder. A second suction port that opens into the chamber, a bypass passage that opens one end to the high-pressure side space of the compressor or the working chamber in the middle of the compression stroke, and the other end to the suction passage, and a communication portion between the bypass passage and the suction passage. The second suction port is provided with passage switching means that allows selective communication between the second suction port and the suction chamber or the bypass passage.

According to the above-described configuration, the return refrigerant that has flowed into the working chamber from the second suction port through the bypass passage into the working chamber at the beginning of the suction stroke expands in the working chamber as the rotor rotates, and is applied to the compressor. The compression work of the return refrigerant is recovered back into the compressor to do work.

Then, when the rotor rotates further and the volume of the working chamber increases and the pressure within the working chamber drops to the pressure on the suction side of the compressor, the working chamber communicates with the first suction port and the refrigerant is activated from the first suction port. It flows into the room.

As a result, the compressor discharge capacity can be reduced, and since there is no loss due to return refrigerant, the compressor efficiency does not decrease, and the discharge temperature does not rise by the amount of loss.

Embodiment Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 3 of the accompanying drawings.

In the figure, reference numeral 11 denotes a cylinder having a cylindrical inner wall, and a front side plate 12 and a rear side plate 13 are disposed at both ends of the cylinder 11.

In addition, there is a small gap A between the inner wall of the cylinder 11 and the inner wall of the cylinder 11.
A rotor 14 is rotatably supported via a rotor 14, and a vane 15 is slidably held on the rotor 14 to form an operating chamber 16.

Working chamber 1 whose volume increases or decreases as the rotor 14 rotates
In the working chamber 16 on the volume increasing side of the working chamber 16, a first suction port 17 opens at a position where the maximum volume is formed, and a second suction port 18 opens near the minute gap. The first rgL port 17 communicates with the suction chamber 19 , and the second suction port 18 communicates with the suction chamber 19 via a suction passage 20 .

On the other hand, a bypass passage 21 opens at one end of the working chamber 16 on the volume decreasing side, and a discharge port 23 opens near the minute gap A. The other end of the bypass passage 21 opens into the suction passage 20. A passage switching valve 22 is disposed in a communication portion between the bypass passage 21 and the suction passage 20, and its operation allows communication between the second suction port 18 and the suction chamber 19 or between the second suction port 18 and the bypass passage 21. It is configured to communicate with each other.

Next, the operation of the configuration of this embodiment will be explained.

First, a case where the refrigerating capacity of the compressor is relatively small, such as when the compressor is operated at low speed, will be described.

In this case, the state is detected by an engine speed detection sensor (not shown) and high/low pressure signals of the refrigeration cycle, and the passage switching valve 22I'i communicates the suction chamber 19 with the second suction port 18 as shown in FIG. The refrigerant that has flowed into the suction chamber 19 from the refrigeration cycle (not shown) is sucked into the working chamber 16 through the first suction port 17 and the second suction port 18, and the amount thereof is compressed and discharged from the discharge port 23. It will be done.

Next, a case will be described in which the refrigerating capacity of the compressor is relatively large, such as when the compressor is operated at high speed, and therefore the discharge capacity is reduced to reduce the power consumption of the compressor.

In this case, the passage switching valve 22 communicates the passage passage 21 with the second suction port 18 as shown in FIG. 20. It returns to the working chamber 16 which is in the suction stroke via the second suction port 18. When the vane 15 passes through the second suction port 18 due to the rotation of the rotor 14 and forms the working chamber 16 on the delayed side of the vane 15, the pressure rise due to the returning refrigerant and the volume of the working chamber 16 increase. The two factors of pressure drop due to increase exist at the same time, but by appropriately selecting the amount of return refrigerant, the re-expansion of the return refrigerant can be completed just before the working chamber 16 communicates with the first suction port 17, and the working chamber can be completely re-expanded. 16 internal pressure can be reduced to the suction chamber 19 internal pressure. When the rotor 14 further rotates and the working chamber 16 communicates with the ':1IJ1 suction hole 17, the refrigerant in the suction chamber 19 is sucked into the working chamber 16.

Therefore, the return refrigerant is expanded to the internal pressure of the suction chamber 19, that is, the compressor suction pressure, and the compressor does work by that amount, which makes it possible to reduce the discharge capacity without reducing the compressor efficiency and reduce the loss. The discharge temperature does not rise to the extent that there is no .

In this embodiment, the opening at one end of the bypass passage 21 is provided in the working chamber 16 in the middle of the compression stroke, but the same effect can be obtained even if it is provided on the high-pressure side of the refrigeration cycle including the compressor.

Further, in this embodiment, communication between the 21st population 18 and the suction chamber 19 or the bypass passage 21 is performed by the passage switching valve 22, but the other end opening of the bypass passage 21 is
Alternatively, a passage opening/closing valve may be provided in the bypass passage and a passage opening/closing valve in the second suction port 18, which opens in the suction side working chamber 16 near the minute gap A and independently blocks communication between the passages. A check valve may be provided to prevent backflow from the working chamber 16.

Furthermore, although a so-called perfect circular vane rotary compressor is shown in this embodiment, any rotary compressor whose suction stroke can be used as an expander may be used, and the present invention is not limited to the above embodiment. .

Effects of the Invention The present invention provides the following advantages:
The refrigerant that has been given compression work is returned from the bypass passage to the working chamber via the second suction port by the passage switching valve, and effective expansion work is extracted from the returned refrigerant before the working chamber communicates with the second suction port. Therefore, since there is no loss due to return refrigerant, the compressor discharge capacity can be reduced without reducing compressor efficiency, and the rise in discharge temperature can also be suppressed.

[Brief explanation of drawings]

FIG. 1 is an axial cross-sectional view of a variable capacity rotary compressor according to an embodiment of the present invention, and FIG. 2 is a view similar to FIG. 1. 11... Schilling, 12... Front side plate, 13... Rear side plate, 14... Rotor, 15... Vane, 16...・・・・・・Working chamber,
17...First suction port, 18...Second suction port, 19...Suction chamber, 20...Suction passage, 21...・Bypass passage, 22...
・Passage switching valve. Name of agent: Patent attorney Masao Nakao and 1 other person
---Shirin 7゛/2---fi4 group J# 13--One type capital example/4-One hitch-7/2---I 乍过 2θ-1 Berito 21---Paipa 9■ 11-11 cylinder. 14--Bit-7 15---Bane 16--I 乍过J (17---Rod 1 Rokin\, Mouth 2)-M-Bye/V Cho

Claims (1)

[Claims] A cylinder having a cylindrical inner wall, a side plate closing both ends of the cylinder, a rotor rotatably disposed within the cylinder and forming a minute gap with the inner wall of the cylinder, and a rotor capable of sliding on the rotor or the cylinder. a first suction port that opens into the working chamber at a position where the working chamber, which is defined by the cylinder, the side plate, the rotor, and the vane and whose volume changes with rotation of the rotor, has a maximum volume; a second suction port that opens into the working chamber on the volume increasing side near the minute gap; a suction chamber that communicates with the first suction port; a suction passage that communicates this suction chamber with the second suction port; a bypass passage that opens one end to the high-pressure side space of the machine or the working chamber in the middle of volume reduction and the other end to the suction passage; A variable capacity rotary compressor equipped with a passage switching means that allows two suction ports to communicate selectively with a suction chamber or a bypass passage.