JPH028158B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention particularly relates to a rotary compressor having a structure for reducing high frequency noise.

[Technical background of the invention and its problems]

FIG. 1 shows a conventional rotary compressor. That is, inside the airtight container 1, there is a motor section 2.
An electric compressor main body 4 consisting of a compressor section 3 and a compressor section 3 connected together.
is accommodated. The electric motor section 2 includes a stator 5 fitted into the closed container 1 and a rotor 7 fitted onto the rotating shaft 6. In the compressor section 3, a roller 8 is fitted to an eccentric crank section 6a of the rotating shaft 6, and the roller 8 is housed in a cylinder 9 so as to be eccentrically rotatable. One opening of the cylinder 9 is closed by a main bearing 10, and the other opening is closed by a sub-bearing 11. The main bearing 10 has a discharge valve 12
and is covered with a valve cover 13.

Therefore, by energizing the electric motor section 2,
The rotating shaft 6 rotates, and the roller 8 rotates eccentrically within the cylinder 9 to introduce the compressed gas into the cylinder 9 and compress it. When the gas is compressed to a predetermined pressure, the discharge valve 12 opens and discharges the compressed gas into the valve cover 13. This compressed gas is once led into the closed container 1 from the valve cover 13, and further led out to external equipment via the connecting pipe P.

By the way, in this type of rotary compressor, high frequency noise is especially large compared to a normally used reciprocating compressor. The reason for this is that in the case of a rotary compressor, the stator 5, cylinder 9, etc. are directly attached and fixed to the closed container 1. The vibrations generated in the stator 5 and the cylinder 9 are transmitted to the closed container 1, and are radiated from the closed container 1 as high frequency noise of approximately 3 kHz or higher.

Therefore, as measures to reduce this noise, we have increased the wall thickness of the sealed container 1 and the main and auxiliary bearings 10 and 11 to attenuate vibration transmission, and increased the clearance between the shaft and the bearings to reduce noise. In view of this, attempts have been made to reduce vibration transmission by setting the optimum value and particularly by increasing the lubricity of the compressor section 3.

However, these measures only partially prevent vibration transmission and do not target the source of vibration noise, so there is a limit to the noise reduction effect. Further, an increase in the thickness of each member leads to disadvantages such as an increase in weight and cost.

Therefore, it is effective to find the source of noise in the rotary compressor and take appropriate measures.
FIG. 10 is an analysis of the generation pattern of high frequency noise in a rotary compressor for a refrigerator, for example. That is, when the roller 8 rotates eccentrically in the counterclockwise direction in the figure with respect to the cylinder 9 as shown in FIG. Set a certain crank rotation angle θ. Figure A shows the discharge valve 12 relative to the crank rotation angle θ.
represents a change in the movement of The discharge valve 12 is closed while the crank rotation angle θ ranges from 0° to approximately 250°, and becomes fully open at approximately 250°. After that, it heads toward the closing direction, but about
As will be described later, the displacement is interrupted between 280° and 310°, and there are large fluctuations beyond this point until it is completely closed at a position of 360°. Figure B shows the pressure change inside the cylinder 9. It can be seen that the internal pressure rises rapidly as the crank rotation angle increases from 0° to approximately 250°, and the gas to be compressed is effectively compressed. At about 250 degrees, the internal pressure reaches its peak, and the discharge valve 12 opens and drops. However, the internal pressure fluctuates dramatically between approximately 280° and 310°. This is due to the large change in movement of the discharge valve 12. Along with this, as shown in Figure C, actual bearing vibration is greatest when the crank rotation angle is approximately 280° to 310°, and as shown in Figure D, actual high-frequency vibration is caused by crank rotation. It is largest at an angle of approximately 280° to 310°.

That is, both bearing vibration and high-frequency noise become the largest when the fluctuation of the discharge valve 12 is large. This is inferred as described below. When the discharge valve 12 opens at a position where the crank rotation angle is 250 degrees, the gas compressed within the cylinder 9 protrudes into the valve cover 13 and collides with its wall surface. A portion returns into the cylinder 9 through the discharge hole. While the discharge valve 12 is open, the above action is repeated, resulting in a so-called pressure pulsating wave. In the cylinder 9, a fluctuating force acts on the roller 8 under the influence of such pressure pulsations, and due to the clearance between the roller 8 and the eccentric crank part of the rotating shaft 6, they repeatedly collide with each other. I'll give it back. As a result, the rotating shaft 6 hits each of the bearings 10 and 11, causing bearing vibration, which is transmitted to the closed container 1 and turns into high-frequency noise.

In this way, it can be concluded that the high frequency noise peculiar to rotary compressors is caused by the pressure pulsating waves generated in the valve cover 13 returning into the cylinder 9. The return timing is immediately after the discharge valve 12 is opened, but it varies depending on the suction pressure, discharge pressure, and temperature of the compressor, and the shape of the valve cover 13. For refrigerators and housing cases, θ=280° to 310°; for air conditioners and dehumidifiers, θ=
It was found to be between 190° and 220°.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a rotary compressor that can reduce high-frequency noise by absorbing pressure pulsations caused by opening of a discharge valve. It is something to do.

[Structure of the invention]

In the present invention, a roller is fitted to an eccentric crank portion of a rotating shaft, this roller is accommodated in a cylinder so as to be eccentrically rotatable, and one opening surface of this cylinder is closed with a bearing equipped with a discharge valve. In a rotary compressor covered with a valve cover, a relief recess is provided in a part of the inner circumferential wall of the cylinder and at a position where the blade comes into contact after the gas in the cylinder is compressed and the discharge valve is opened. This is a rotary compressor characterized by:

The present invention also provides a method in which a roller is fitted to an eccentric crank portion of a rotating shaft, this roller is accommodated in a cylinder so as to be eccentrically rotatable, and one opening surface of this cylinder is closed with a bearing equipped with a discharge valve. In the bearing covered with a valve cover, a guide hole is provided in the peripheral surface of the bearing covered by the valve cover, and a gas relief hole is bored in the rotating shaft, which communicates intermittently with the guide hole as the shaft rotates. This rotary compressor is characterized by the following:

[Effect]

In the present invention, after the gas in the cylinder is compressed and the discharge valve is opened, the blade comes into contact with the relief recess provided in the inner circumferential wall of the cylinder. In this state, the compressed gas chamber and the suction gas chamber in the cylinder are temporarily communicated through the relief recess, and pressure pulsations in the compressed gas chamber escape to the suction gas chamber and are absorbed. In this way, the initial pressure pulsation that occurs when the discharge valve opens is absorbed, so no pressure pulsation occurs even when the roller passes through the relief recess.

Further, in the present invention, after the gas in the cylinder is compressed and the discharge valve is opened, the gas relief hole formed in the rotating shaft instantaneously communicates with the guide hole provided in the bearing. At this time, the compressed gas discharged to the valve cover is temporarily released into the closed container from the guide hole through the gas relief hole, so that the pressure pulsations escape into the closed container and are absorbed.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on FIG. 2 and FIGS. 3A and 3B. Note that the same parts as in FIG. 1 above are given the same numbers and the explanation will be omitted. That is, FIG. 2 shows the main part of the compressor section 3 of a rotary compressor, and one opening surface of the cylinder 9a is connected to the rotation shaft 6.
It is closed by a main bearing 10 that pivots. This main bearing 10 includes a discharge valve 12 and a valve cover 13.
covered with Eccentric crank portion 6a of the rotating shaft 6
is located within the cylinder 9a, and the roller 8 is fitted therein. As shown in FIG. 3A, the cylinder 9a
A blade groove 15 is provided in the inner circumferential wall of the blade. A blade (not shown) is inserted into the blade groove 15 and is elastically pressed so that its leading edge comes into contact with the roller 8. The roller 8 is adapted to rotate in the clockwise direction in the figure within the cylinder 9a. A discharge notch 16 is provided on the inner circumferential wall of the cylinder 9a at a position α° on the opposite rotational direction side of the roller 8 with respect to the central axis L of the blade groove 15 as a reference. As shown in FIG. 3B, this discharge notch 16 is formed by cutting out a corner of the upper surface of the cylinder 9a, and is aligned with the discharge hole 17 provided in the main bearing 10. Moreover, the central axis L of the blade groove 15
A relief recess 18 serving as a noise reduction means is provided at a position on the rotational direction side of the roller 8 with reference to . This relief recess 18 is located in the cylinder 9a.
This is a recess with a semicircular cross section provided from the upper end surface to the lower end surface. For compressors for refrigerators and housing cases, the angle is 280° to 310°, and for air conditioners and dehumidifiers, the angle is 190 to 220°.

Thus, the roller 8 rotates eccentrically within the cylinder 9a, and together with the blade, the cylinder 9a is divided into a compressed gas chamber and a suction gas chamber. The capacity of each of these chambers changes as the roller 8 rotates, and the gas in the compressed gas chamber is gradually compressed. When the contact position of the roller 8 in the cylinder 9a reaches this side of the relief recess 18, the gas is compressed to a predetermined pressure.
Discharge valve 12 opens. Therefore, the gas is led out into the valve cover 13 via the discharge notch 16 and the discharge hole 17. Since the discharged gas is under high pressure, pressure pulsations occur between the valve cover 13 and the compressed gas chamber within the cylinder 9a. However, the contact position of the roller 8 in the cylinder 9a is shifted to the relief recess 18. Here, the compressed gas chamber and the suction gas chamber communicate with each other, and the pressure pulsations in the compressed gas chamber escape to the suction gas chamber and are absorbed. Since the initial pressure pulsation that occurs when the discharge valve 12 opens is absorbed, even if the roller 8 changes its contact position from the relief recess 18 to the blade groove 15 side, almost no pressure pulsation occurs, and high frequency Noise is reduced.

In the above embodiment, the relief recess 18 as a noise-reducing means is provided from the upper end surface to the lower end surface of the cylinder 9a, but the invention is not limited to this. For example, as shown in FIGS. 4A and 4B, , the relief notch 18a may be provided only at the corner of the upper end surface of the cylinder 9b. That is, it has substantially the same shape as the discharge notch 16. The position is exactly the same as in the above embodiment. Therefore, the same effect is obtained.

Further, it may be a silencing means as shown in FIG. 5 and FIGS. 6A and 6B. That is, the main bearing 10
It consists of a guide hole 20 provided in the boss portion 10a and a gas relief hole 21 provided in the rotating shaft 6. The guide hole 20 is positioned at an angle α° in the counter-rotation direction of the roller 8 with respect to the central axis L of the blade groove 15 as a reference. The gas escape hole 21 includes a lead-out hole 21a that is bored at a position β° in the rotational direction of the roller 8 with respect to the center axis L as a reference, and at a height opposite to the guide hole 20, and A shaft hole 21 provided along the axis of the rotating shaft 6 so as to communicate with the hole 21a.
It consists of b. This shaft hole 21b opens at the lower end surface of the rotating shaft 6. Note that the relationship α°+β°=360°−°.

Therefore, the guide hole 20 and the outlet hole 21a communicate with each other only at the moment when the rotating shaft 6 rotates and the rotation angle becomes .degree., that is, intermittently as the rotating shaft 6 rotates. Therefore, a part of the gas guided into the valve cover 13 when the discharge valve 12 is opened escapes into the closed container 1 from the shaft hole 21b via the guide hole 20 and the outlet hole 21a. In the end, valve cover 13
The internal pressure pulsations can be released into the closed container 1 to reduce high frequency noise.

Note that in the above embodiment, the roller 8 is used as a single unit, but the roller 8 is not limited to this, and may be configured as described below. That is, FIG. 7 shows a rotary compressor, and this compressor section 3 is provided with a muffling means (not shown). Also,
An inner roller 8 is attached to the eccentric crank portion 6a of the rotating shaft 6.
A roller 8 having a double structure consisting of a roller a and an outer roller 8b is fitted. This roller 8 is housed in a cylinder 9 so as to be eccentrically rotatable, which is the same as in the above embodiment. As shown in FIGS. 8 and 9, an oil groove 22 is formed along the outer peripheral surface of the inner roller 8a.
are provided, and a plurality of oil holes 23 are radially drilled to communicate the oil groove 22 and the inner circumferential surface. Alternatively, an inner roller 8a having such a shape
Instead, an inner roller 8a' made of a containing material may be used. In the case of this inner roller 8a', no processing is required.

As the rotating shaft 6 rotates, the lubricating oil is sucked up from the inner bottom of the closed container 1, and the lubricating oil is drawn up from the circumferential surface of the eccentric crank part 6a into the oil holes 23 and the oil grooves 22.
and forms an oil film on the joint surface between the inner roller 8a and the outer roller 8b. From this, within
Although the outer rollers 8a and 8b rotate freely, the oil film between them absorbs the shock and prevents pressure fluctuations within the cylinder 9 from being transmitted to the eccentric crank portion 6a. Furthermore, the circumferential speed of the outer roller 8b decreases, resulting in reduced wear on the blade 24. Even if the rotating shaft 6 rotates at a high speed of about 10,000 rpm,
There is no risk of running out of oil.

Furthermore, even if the inner roller 8a' is formed of an oil-impregnated material, the same effects of vibration absorption and wear reduction can be obtained.

〔Effect of the invention〕

The present invention has the effect of absorbing pressure pulsations and reducing high-frequency noise with only simple processing without adversely affecting costs.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a rotary compressor showing a conventional example of the present invention, Fig. 2 is a longitudinal cross-sectional view of a main part of a rotary compressor showing an embodiment of the present invention, and Fig. 3A is a cylinder thereof. 4A is a plan view of a cylinder showing another embodiment, FIG. 4A is a plan view of a cylinder showing another embodiment, FIG.
5 is a vertical sectional view of a main part showing another embodiment, FIG. 6A is a plan view of the main bearing, FIG. 6B is a plan view of the rotating shaft, and FIG. The figures also show a longitudinal sectional view of a rotary compressor showing another embodiment, Fig. 8 is a cross-sectional plan view of the compressor section, Fig. 9 is an exploded perspective view thereof, and Figs. 10 A to E show pressure pulsation. It is a figure for explaining. 6... Rotating shaft, 6a... Eccentric crank part, 8...
...Roller, 9a...Cylinder, 12...Discharge valve,
10...Main bearing, 13...Valve cover, 18...
...Relief recess, 20...Guide hole, 21...Gas release hole.

Claims (1)

[Claims] 1. A roller is fitted to an eccentric crank portion of a rotating shaft,
This roller is housed in a cylinder so as to be eccentrically rotatable, one opening surface of the cylinder is closed with a bearing equipped with a discharge valve, and this bearing is covered with a valve cover, in which a part of the inner circumferential wall of the cylinder is closed. ,
and a relief recess provided at a position where the blade comes into contact after the gas in the cylinder is compressed and the discharge valve is opened to temporarily communicate the compressed gas chamber and the suction gas chamber in the cylinder. Rotary compressor. 2 Fit the roller to the eccentric crank part of the rotating shaft,
This roller is housed in a cylinder so as to be eccentrically rotatable, one opening surface of the cylinder is closed by a bearing equipped with a discharge valve, and this bearing is covered with a valve cover, in which the bearing circumference covered by the valve cover is A guide hole provided in the surface part, and a closed container that is bored in the rotating shaft and communicates intermittently with the guide hole as the rotation occurs, and the compressed gas discharged to the valve cover is passed from the guide hole through the rotating shaft. A rotary compressor characterized by having a gas release hole for temporarily releasing gas inside the compressor.