JPH0377393B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a hermetic compressor, and more particularly to a muffling device that prevents air column resonance occurring in the circumferential direction within a hermetic container.

(B) Prior Art A general hermetic rotary compressor will be explained based on FIG. 1. 1 is a hermetic container, and inside this hermetic container, an electric element 2 is placed in the upper part, and a rotary compression element 3 is placed in the lower part. are placed respectively. The electric element 2 includes a stator 4 attached to the inner wall of the closed container 1, and a rotor 6 provided inside the stator and having a rotating shaft 5 inserted therethrough. The rotary compression element 3 includes a cylinder 7, a roller 9 that rotates inside the cylinder 7 by an eccentric portion 8 of a rotating shaft 5, and a vane 10 that comes into contact with this roller and divides the inside of the cylinder 7 into a high pressure chamber and a low pressure chamber.
, an upper bearing part 11 and a lower bearing part 12 that seal the opening of the cylinder 7. The upper bearing portion 11 is provided with a discharge port 13 and a discharge valve 14 opposite thereto. 15 is a discharge valve 14
It is a cup-shaped muffler body that surrounds the upper bearing part 11 and is attached to the upper bearing part 11. A conventional cup-shaped muffler body 15 shown in FIG. 2 has three seat recesses 16, 16, 16 for attaching bolts at approximately equal intervals to divide the muffler portion into three parts. This muffler section is divided into three parts, and the part where the discharge valve 14 is attached is wide, and the other two parts are narrow. Therefore, when two outlet holes 17 and 18 having the same diameter are provided in the cup-shaped muffler body 15 symmetrically with respect to the axis, the drilling locations are limited, and one outlet hole 17 is close to the discharge port 13, while the other The outlet hole 18 had to be located away from the discharge port 13.

In the muffler having this structure, the discharge gas that has pushed open the discharge valve 14 from the discharge port 13 and flowed into the cup-shaped muffler body 15 is discharged through the outlet holes 17 and 18.
are provided in the cup-shaped muffler body 15 symmetrically with respect to the axis, and the pressure pulsations of the refrigerant discharged from these outlet holes mutually generate a standing wave that causes air column resonance in the space inside the closed container 1. The standing waves formed in the circumferential direction inside the sealed container 1 are canceled out by creating an opposite phase relationship.

(c) Problems to be Solved by the Invention However, the distance attenuation and the attenuation due to passage resistance differ depending on the distance from the discharge port 13 for the outlet holes 17 and 18, and the outlet holes 17 and 18 have different attenuation due to the passage resistance. The excitation force from the exit hole 17 is large, and the other exit hole 18 has a large passage resistance.
Since the excitation force from
Even if the standing waves generated in the space inside the closed container 1 by the excitation force due to the pressure pulsations of the refrigerant discharged from 7 and 18 have opposite phases, the amplitudes of these standing waves are different, so they are not mutually exclusive. There was a problem in that standing waves could not be canceled out completely and remained in the space inside the closed container 1, and noise due to air column resonance was generated from the closed container to the outside.

The present invention solves the above-mentioned problem, and provides a noise reduction device for a hermetic compressor that reduces noise caused by standing waves transmitted from inside a hermetic container to the outside.

(d) Means for Solving the Problems This invention houses an electric element and a compression element driven by a rotating shaft of the electric element in a closed container, and connects the compression element to a cylinder and a compression element driven by a rotating shaft of the electric element. It consists of a roller that rotates the cylinder, an upper bearing part and a lower bearing part that seal the opening of the cylinder and pivotally support the rotating shaft, and a cup-shaped muffler attached to the upper bearing part. In a hermetic compressor, the cup-shaped muffler is provided with a discharge port that communicates with the interior of the cup-shaped muffler, and the cup-shaped muffler has a plurality of discharge ports that are located at different distances from the discharge port and that are approximately symmetrical with respect to the axis of the rotating shaft. Two outlet holes are provided, and the size of these outlet holes is formed to have an area that is a ratio of the distances from the discharge port to each outlet hole.

(E) Effect This invention is configured as described above, so that
The refrigerant compressed in the cylinder and discharged from the discharge port into the cup-shaped muffler is made to flow into the sealed container from each outlet hole, and the pressure pulsation of the refrigerant flow discharged from each outlet hole causes the refrigerant to flow inside the sealed container. This system equalizes the force that applies vibration to the refrigerant gas, and also makes the standing waves generated inside the sealed container have opposite phases, so that the standing waves that generate noise outside the sealed container cancel each other out. .

(F) Example The present invention will be explained below based on the example shown in FIG.

Note that the same parts or equivalent parts as in the conventional example will be described with the same reference numerals.

The cup-shaped muffler 19 of the present invention has two outlet holes 2 at different distances from the discharge port 13 and at positions substantially symmetrical with respect to the axis of the rotating shaft 5.
0 and 21, and among these outlet holes, one outlet hole 20 having a shorter distance from the discharge port 13 has a smaller area, and the other outlet hole 21 having a longer distance from the discharge port 13 has a larger area. ing. Furthermore, the sizes of the two outlet holes 20 and 21 are formed to have an area that is a ratio of the distances from the discharge port 13 to the respective outlet holes 20 and 21. Furthermore, the total area of the two outlet holes 20 and 21 is the area of the discharge port 13.
The cup-shaped muffler 1 has approximately the same size as the area of
The pressure of the refrigerant discharged from the discharge port 13 is prevented from increasing within the refrigerant 9.

In the silencer for a hermetic compressor configured as described above, the refrigerant that has flowed into the cylinder 7 is compressed by the roller 9, and is discharged from the discharge port 13 into the cup-shaped muffler 19 by opening the discharge valve 14. be done. The refrigerant inside this muffler has two outlet holes 2.
0 and 21 into the sealed container 1.

Two outlet holes 20, 2 of the cup-shaped muffler 19
1, by forming the size of these outlet holes to have an area that is the ratio of the distances from the discharge port 13 to the respective outlet holes 20 and 21, the airtight container 1 is created by pressure pulsations of the refrigerant at these outlet holes. This makes it possible to equalize the force that applies vibration to the refrigerant gas inside. Moreover, by providing the two outlet holes 20 and 21 at approximately symmetrical positions with respect to the axis of the rotating shaft 5 in the sealed container 1 and shifting them by 180 degrees, the refrigerant gas flows out from one of the outlet holes 20. The force that applies vibration and the force that flows out from the other outlet hole 21 and applies vibration to the refrigerant gas are made to have opposite phases on opposite sides. The two exit holes 20 and 21 vibrate the refrigerant gas in the sealed container 1, and the standing waves that are formed in the circumferential direction inside the sealed container have the same size and opposite phases. This is canceled out by the interference effect. Therefore, the compressor has reduced noise due to air column resonance.

In addition, the force that vibrates the refrigerant gas due to the pressure pulsations of the refrigerant discharged from the discharge port 13 is caused by a slight difference in the time at which the refrigerant reaches the two outlet holes 20 and 21, resulting in a constant force created by the pressure pulsations. The phases of the waves are slightly shifted, and some standing waves remain in the space inside the closed container 1 without being canceled out completely. However, since this remaining standing wave is generated from the phase difference between the pulsations from the two exit holes 20 and 21 and has a small amplitude, it is unlikely to become a source of noise due to air column resonance.

Figure 4 is a noise characteristic diagram showing experimental data.
From this characteristic diagram, it can be seen that noise in the frequency range of 200Hz to 1000Hz can be significantly reduced compared to the conventional method.

(G) Effects of the Invention As described above, according to the present invention, the cup-shaped muffler is provided with two outlet holes at different distances from the discharge port and at positions that are approximately symmetrical with respect to the axis of the rotating shaft. Since the size of these outlet holes was formed to have an area that was the ratio of the distance from the discharge port to each outlet hole, the pressure pulsations of the refrigerant discharged from each outlet hole caused the refrigerant in the closed container to At the same time, the standing waves formed in the space inside the closed container due to the pressure pulsations of the refrigerant discharged from the outlet hole cancel each other out due to interference, and the noise is reduced. This makes it difficult for standing waves to form inside the closed container, which is the source of the waves. Moreover, this invention is applicable regardless of the position of the discharge port and each outlet hole.
This prevents standing waves from forming within the closed container.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a general rotary compressor, FIG. 2 is a plan view of a conventional cup-shaped muffler body, FIG. 3 is a plan view of a cup-shaped muffler body showing an embodiment of the present invention, and FIG. The figure is a noise measurement diagram of the present invention and a conventional example. DESCRIPTION OF SYMBOLS 1... Airtight container, 2... Electric element, 3... Rotating compression element, 11... Upper bearing part, 13... Discharge port, 14... Discharge valve, 19... Cup-shaped muffler body, 20, 21... ...Exit hole.

Claims (1)

[Claims] 1. An electric element and a compression element driven by a rotating shaft of the electric element are housed in a closed container, and the compression element is connected to a cylinder, a roller rotating inside the cylinder, and an opening of the cylinder is sealed. It consists of an upper bearing part and a lower bearing part that pivotally support the rotating shaft, and a cup-shaped muffler attached to the upper bearing part, and the upper bearing part has a discharge port that communicates between the inside of the cylinder and the inside of the cup-shaped muffler. In the hermetic compressor, the cup-shaped muffler is provided with two outlet holes at different distances from the discharge port and at positions substantially symmetrical with respect to the axis of the rotating shaft, A silencer for a hermetic compressor, characterized in that the sizes of these outlet holes are formed to have an area that is a ratio of the distances from the discharge port to each outlet hole.