JPH04203387A - Rotary compressor - Google Patents

Abstract

PURPOSE:To improve a volumetric efficiency, improve a capability of a compressor and improve a coefficient of performance by a method wherein an adjusting mechanism such as a nozzle is disposed near an output of a suction port and a spacing volume is disposed near an outlet of the suction port. CONSTITUTION:A suction passage of a cylinder 6 is provided with a tapered metering part 6a of which sectional rear is reduced toward an inner diameter part of a cylinder. A passage resistance difference between a flowing-in of refrigerant gas and a flowing-out of refrigerant gas is provided, an amount of refrigerant gas accumulated within the cylinder and compressed in it is increased, and thus a volumetric efficiency can be improved. A through-pass part 17 directed toward a height of the cylinder is disposed in the midway part of a cylinder suction passage, the suction passage is closed by one end surface of a main bearing 7a and another end surface of a sub-bearing 7b and a spacing volumetric part is formed. With such an arrangement, an amplitude of pressure pulsation is increased and at the same time even under a new number of rotation, a certain pressure pulsation may be generated and a volumetric efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a structure suitable for preventing backflow on the suction side and improving volumetric efficiency in rotary compressors used in room air conditioners, refrigerators, etc.

[Conventional technology]

A conventional rotary compressor will be explained with reference to FIGS. 4 to 6. FIG. 4 is a longitudinal sectional view of a rolling screw type rotary compressor, which is a type of conventional rotary compressor.

A motor section 2 and a pump section 3 are housed in an airtight container 1, and a motor rotor 2a and a crankshaft 4 are integrally assembled. A roller 5 is fitted into the eccentric portion 4a of the crankshaft 4, and is installed inside a cylinder 6, and both end surfaces of the cylinder 6 are sealed by a main bearing 7a and a sub-bearing 7b. As the crankshaft 4 rotates, the roller 5 rotates eccentrically within the cylinder 6, and following this, the vane 8 reciprocates to partition the inside of the cylinder 6 into a suction chamber 9 and a compression chamber 10, and the crankshaft As the shaft 4 rotates, refrigerant gas is sucked into the suction chamber 9 through the suction boat 1 and compressed by reducing the volume of the compression chamber 10. Discharge into. When the roller 5 passes through the suction boat 11 in this way, the compression chamber no longer communicates with the suction boat, so there is no need for a suction valve such as a check valve on the suction side, which reduces the number of parts in the rotary compressor. This is a major feature of reliability improvement and cost reduction.

The suction side refrigerant piping usually has a refrigeration cycle (not shown).
In order to ensure reliability when liquid is returned from the evaporator, an accumulator 13 is provided to temporarily store liquid refrigerant. The structure of the accumulator 13 consists of an outer case 13 a and a suction vibrator 13 b that is provided to protrude inside the case and communicates with the compressor suction port 11 . The accumulator I3 also works as a refrigerant gas pressure buffer, and at a rotational frequency f determined mainly by the length L of the suction vibrator 13b, its cross-sectional area A, and the theoretical volume V of the cylinder chamber that can be displaced during one rotation of the crankshaft, the accumulator I3 acts as a refrigerant gas pressure buffer. It is known that an air column resonance phenomenon occurs in which the internal pressure door movement increases, and the volumetric efficiency increases.

("Practical machine series positive displacement compressor", (Sangyo Tosho),
p, 83) The frequency at this time is given by the following equation.

fl-□ 4. (L+V/A) Here, a is the sound speed of the refrigerant.

[Problem to be solved by the invention]

In the above prior art, the actual compression stroke starts when the crank angle Q is equal to or greater than Qs, and ends at the crank angle Qe.

Between ~O0 and Q8, the pressure inside the cylinder becomes higher than the suction pressure Ps due to the re-expansion of the compressed gas in the top clearance volume V, and at this time, the refrigerant sucked from the suction port communicating with the cylinder chamber No consideration was given to the fact that the gas flows backward and the volumetric efficiency η9 decreases, resulting in a decrease in compressor capacity and a decrease in the coefficient of performance.

One way to prevent this backflow is to use a check valve as shown in Fig. 6, but in this case, the number of parts including the movable valve body 14 and spring 15 increases, and reliability is reduced. 3. Disadvantages in terms of performance and cost. Further, the volumetric efficiency may be reduced due to the flow resistance caused by the suction valve.

An object of the present invention is to prevent backflow from inside the cylinder to the suction side, and to improve volumetric efficiency, compressor capacity, and coefficient of performance.

A supercharging effect using the air column resonance phenomenon is known as a method to increase η9, but since this method uses resonance, it is only effective within a specific narrow compressor rotational speed range. In recent variable speed compressors using inverters, there has been a problem in that the contribution to performance improvement is small.

Another object of the present invention is to obtain a supercharging effect over a wide rotation speed range.

[Means to solve the problem]

In order to achieve the above object, a throttle mechanism such as a nozzle portion is provided near the suction boat outlet to prevent refrigerant gas flowing into the cylinder from flowing out.

Furthermore, in order to increase the effect of improving volumetric efficiency, a space volume section is provided near the suction port outlet to amplify the pressure pulsation and also generate pressure pulsations at other frequencies to increase the refrigerant gas inside the cylinder. It is designed to push the .

[Effect]

At the inlet of the suction port, a throttling mechanism part such as a nozzle part, which has different flow resistance depending on the flow direction, is installed, so that the resistance is small when the refrigerant gas flows into the cylinder, and the resistance is thick when it flows out to the accumulator side. As a result, the refrigerant gas sucked into the cylinder chamber does not flow back to the suction side, increasing volumetric efficiency.

In addition, the inflow resistance of the throttle part is determined from the cross-sectional area of the suction vibrator.
If the exit area of the constriction part is equal to or greater than that, the inflow resistance will be equal to or less than that without the constriction, and there will be no deterioration in performance due to the provision of the constriction mechanism.

In addition, by providing a space volume near the suction boat outlet, in addition to the frequency f1 that normally generates pressure pulsations, the length of the suction pipe and the volume V of the space volume. Even at the frequency f2 f2- □ 4 (L0V./A), which is determined by do.

Furthermore, by providing the space volume portion, the suction side volume increases, the amplitude of pressure pulsation increases, the supercharging effect increases, and the volumetric efficiency increases.

As described above, by increasing the volumetric efficiency, the capacity of the compressor can be improved and the coefficient of performance can be improved.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 shows a longitudinal cross-sectional view of a main part of a refrigerant suction section of a rotary compressor. The cylinder 6 suction passage is provided with a tapered constricted part 6a whose cross-sectional area becomes smaller toward the inner diameter side of the cylinder.
By providing a difference in flow resistance between the inflow and outflow of refrigerant gas, the amount of refrigerant gas that is sucked into the cylinder, stored, and compressed can be increased, and the volumetric efficiency can be improved.

Further, in the embodiment shown in FIG. 2, the cylinder is provided with a suction hole machined to a large diameter, and a separate piece 16 made of a resin material or the like having a tapered drawing portion is inserted into the suction hole to improve manufacturability. In addition, the cylinder inlet of the suction vibrator has a larger diameter and is connected to
From the minimum cross-sectional area S1 of the suction pipe, the minimum area S of the cylinder inlet throttle part.

is the same or higher, eliminating the increase in flow resistance due to the provision of the throttling mechanism near the suction boat.

FIG. 3 is a perspective view showing the main part of the suction section of a rotary compressor showing another embodiment of the present invention.

The cylinder has a through part 17 in the cylinder height direction in the middle of the cylinder suction passage by molding or broaching, etc., and is closed by the end faces of the main bearing 7a and the sub bearing 7b to form a space volume part. are doing. As a result, the amplitude of the pressure pulsations is increased, pressure pulsations occur even at a new rotation speed, and the volumetric efficiency can be improved. Further, the vicinity of the compression chamber entrance is processed into a tapered shape, and the minimum cross-sectional area thereof is equal to or greater than the cross-sectional area of the suction pipe, and the same effect as that of the embodiment shown in FIG. 2 can be obtained.

〔Effect of the invention〕

According to the present invention, with the throttle mechanism provided near the cylinder inlet, it is possible to increase the passage resistance for flowing back to the suction side with respect to the passage resistance for flowing into the cylinder compression chamber, and it is possible to improve the volumetric efficiency.

Further, by making the cross-sectional area of the cylinder inlet constricted portion equal to or larger than the minimum cross-sectional area of the suction vibrator, there is no increase in loss due to the provision of the constricted portion.

In addition, by providing a volume part in the middle of the suction passage, pressure pulsation is increased and volumetric efficiency is improved, and a new resonance rotation speed is provided, so that a supercharging effect can be obtained in a wide rotation speed range.

As described above, by improving the volumetric efficiency, it is possible to improve the capacity of the compressor and the coefficient of performance.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part of the suction part showing one embodiment of the present invention, Fig. 2 is a sectional view of the main part of the suction part showing another embodiment of the invention, and Fig. 3 is another embodiment of the invention. FIG. 4 is a vertical sectional view of a conventional rotary compressor, FIG. 5 is a sectional view taken along line A-A in FIG. 4, and FIG. 6 is a conventional rotary compressor with a check valve. It is a sectional view of the main part of the suction part. DESCRIPTION OF SYMBOLS 1... Airtight container, 2... Motor, 3... Pump part, 4... Crankshaft, 5... Roller, 6... Cylinder, 7a... Main bearing, 7b... Sub bearing, 8. Vane,
9... Suction chamber, 10... Compression chamber, 11... Suction boat 1-112... Discharge boat, 13... Accumulator, 1.3 b. Suction pipe, 14... Check valve ,
15. Spring, 16. Piece, 17. Penetration part.

Claims (1)

[Claims] 1. By providing a throttle mechanism in the suction section of a rotary compressor that does not have a check device, the passage resistance for fluid to flow into the compression chamber is greater than the passage resistance for fluid to flow back to the suction side. A rotary compressor characterized by its small size. 2. The rotary compressor according to claim 1, wherein the passage cross-sectional area of the compression chamber inlet is equal to or larger than the passage cross-sectional area of the suction side piping. 3. A rotary compressor in which an accumulator and a compression chamber are connected by a suction pipe, characterized in that a space volume portion is provided in the middle of the suction pipe. 4. A rotary compressor characterized in that the first, second, or third aspects of claim 1, 2, or 3 are implemented simultaneously.