JPH11141489A - Rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise by resonance sound and suppress vibrating noise caused by resonance. SOLUTION: This rotary compressor is provided with a compressing mechanism part 29 provided with a muffler 37 covering a discharge port 2 of a cylinder and an electric motor mechanism part 7 imparting rotational power to the compressing mechanism part 9, within a sealing case 1. A resonance frequency within the muffler 37 and a resonance frequency in space 43 within the sealing case 1 formed at the compressing mechanism part 9 and the electric motor mechanism part 7 are mismatched and resonance sound is attenuated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary compressor.

[0002]

2. Description of the Related Art Generally, in a rotary compressor, an electric mechanism comprising a stator and a rotor, and a muffler for covering a discharge port of compressed refrigerant gas are provided in a sealed case having a discharge pipe for discharging to the outside. And a structure in which the gas compressed by the compression mechanism is discharged from the discharge port into the closed case via the muffler.

[0003]

The gas compressed by the compression mechanism is discharged from the discharge port through the muffler into the sealed case, and the discharge area is between the compression mechanism and the electric mechanism. In the closed case.

For this reason, the primary, secondary, tertiary,
.. Among the number of resonance frequencies that follow, the primary resonance frequency, and the primary, secondary, and three of the space inside the closed case having a larger area than the muffler
When, for example, the secondary resonance frequency substantially coincides with the next resonance frequency, the resonance sound is greatly amplified,
The noise further increases through the closed case. further,
Resonance in the space inside the closed case excites the electric mechanism and increases the vibration of the entire compressor.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a rotary compressor in which resonance frequencies do not coincide with each other to reduce noise due to resonance.

[0006]

In order to achieve the above object, according to the present invention, a compression mechanism having a muffler, an electric mechanism for applying rotational power to the compression mechanism, are provided in a sealed case. A rotary compressor that discharges the gas compressed by the compression mechanism from the discharge port into the closed case via the muffler, wherein the resonance frequency in the muffler is formed between the compression mechanism and the electric mechanism. Means for making the resonance frequency inconsistent with the resonance frequency of the space inside the sealed case.

As means for making the resonance frequency in the muffler and the resonance frequency in the space inside the closed case inconsistent, the primary resonance frequency that is the resonance frequency in the muffler is changed to the primary frequency that becomes the resonance frequency in the space inside the closed case. The resonance frequency is set to approximately the middle between the resonance frequency and the secondary resonance frequency.

Alternatively, the inside of the muffler is formed in an annular space,
The ratio of the average perimeter Sc of the space in the closed case to the average perimeter Sm of the annular space in the muffler is defined as Sm / Sc ≒ 2/3.

Alternatively, the muffler is formed in an annular space, and a dead volume is provided in the circumferential direction.と す る 1/3.

In this case, the dead volume formed in a part in the circumferential direction is formed integrally with the muffler, or the dead volume is formed by filling the part in the circumferential direction with another member such as a sound absorbing material. It is preferable that the dead volume is formed by a protrusion that is provided integrally with the bearing member and protrudes into the muffler.

According to the rotary compressor, the gas compressed by the compression mechanism is discharged from the discharge port to the space inside the closed case via the muffler. In this operation, when compressed gas is discharged from the discharge port, noise is attenuated in the muffler. On the other hand, since the primary resonance frequency in the muffler does not match the secondary resonance frequency in the space inside the closed case, amplification of the resonance does not occur, and noise can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a sealed case of the rotary compressor 3. The sealed case 1 has a discharge pipe 5 at the upper end, and an electric mechanism 7 and a compression mechanism 9 are respectively disposed inside.

The electric mechanism 7 comprises a stator 11 fixed to the inner wall surface of the sealed case 1 and a rotor 15 mounted on the shaft 13. When the stator 11 is energized, the shaft 13 Will be given rotational power.

The compression mechanism 9 includes a cylinder 19 fixed to the inner wall surface of the closed case 1 via a frame 17 and a roller 21 disposed in the cylinder 19. The roller 21 is provided on the shaft 13. The eccentric shaft 23 is inserted into the eccentric shaft 23, and the eccentric shaft 23 rotates to give eccentric rotation.

The shaft 13 is rotatably supported by a main bearing member 25 and a sub-bearing member 27.
Is provided with a discharge port 29.

The cylinder 19 is provided with a suction port 33 communicating with the suction pipe 31 and a blade (not shown) which is always in contact with the outer peripheral surface of the roller 21 by a biasing means such as a spring. The compression chamber 35 is formed by the roller 19, the roller 21 and the blade.

The compression chamber 35 communicates with the discharge port 29. The discharge port 29 is covered with a muffler 37 which serves as a muffler chamber, and a discharge valve 39 and a valve stopper 41 for limiting the opening degree of the discharge valve 39 are provided inside.

The muffler 37 is located in a region of a closed casing space 43 formed between the compression mechanism 9 and the electric mechanism 7. An annular space 45 is formed inside the muffler 37, and a peripheral flange is fixed to the main bearing member 25 with a bolt 49, and a resonance frequency in the muffler 37 and a space 43 in the closed case inner space 43 having a larger area than the muffler 37. The resonance frequency is set to be inconsistent.

FIGS. 2 to 7 show specific examples.
2 and 3 show resonance mode diagrams of the space 43 in the closed case. In the figure, when the average circumferential length of the space 43 in the sealed case is Sc, + indicates a node with X as a node and the sound pressure has a plus side, and-indicates a minus side with a sound pressure of minus. The primary resonance frequency fc1 (FIG. 2) and the secondary resonance frequency fc2 (FIG. 3) in the circumferential direction are expressed by the following equations.

[0021]

Fc1 = C / Sc, fc2 = 2C / Sc (1) where C is the sound velocity of the gas at the time of discharge. Sc is obtained by Sc = π (R1 + R2).

R1: maximum radius, R2: minimum radius On the other hand, on the muffler 37 side, as shown in FIG. The plus side indicates the antinode, and the minus indicates the negative side of the sound pressure. At this time, the primary resonance frequency fm1 of the primary, secondary, tertiary,... The first resonance frequency fc1 and the second resonance frequency fc2 of the space 43 within the case are set to approximately the middle of (fc1 + fc2) / 2.

That is, when the average circumferential length in the muffler 37 is Sm, the primary resonance frequency fm1 in the circumferential direction is expressed by the following equation.

Fm1 = C / Sm (2) where Sm is obtained by Sm = π (R1 + R2).

R1: maximum radius, R2: minimum radius According to the above equation, by setting the ratio of Sm to Sc to 2/3, the primary resonance frequency in the muffler 37 can be changed to the value in the closed case space 43. It is possible to make the frequency substantially midway between the primary resonance frequency and the secondary resonance frequency.

When a circumferential dead volume 51 is provided in the muffler 37 as shown in FIG.
Is defined as Sm1, the primary resonance frequency fm1 in the muffler 37 is expressed by the following equation.

Fm1 = 0.5C / Sm1 (3) where Sm1 is Sm1 = π (R1 + R2) (360 °
−θ) / 360.

Θ indicates the dead volume angle.

Therefore, according to the above equation, the ratio of _Sw1 to Sc is set to 1
/ 3, the primary resonance frequency in the muffler 37 becomes
It is possible to make the resonance frequency approximately halfway between the primary resonance frequency and the secondary resonance frequency in the space 43 in the close inner case.

Here, a specific example of the embodiment of the present invention will be described.

The maximum / minimum radius of the space 43 in the closed case is 65/8 mm, and the maximum / minimum radius in the muffler 37 is 24 / mm.
When the speed of sound of gas is 12 mm and the speed of sound is 190 m / sec,
The primary resonance frequency of the space 43 in the closed case is about 828H
z, the secondary resonance frequency becomes about 1657 Hz, and the muffler 3
The primary resonance frequency in 7 substantially coincides with 1680 Hz from the equation (2). Then, by providing a dead volume 51 of about 120 ° in the circumferential direction, the primary resonance frequency is set to 1240 Hz which is substantially intermediate between the primary resonance frequency and the secondary resonance frequency of the space 43 in the closed case according to the equation (3). It becomes possible.

On the other hand, as the dead volume 51 provided in the muffler 37, it is desirable to use a sound absorbing material capable of reducing noise in a wide frequency range. However, as shown in FIG.
1 may be formed integrally with the muffler 37.

Alternatively, as shown in FIG.
5 may be integrally provided with a protruding portion 53 that partially fills the space inside the muffler 37 to form the dead volume 51.

According to the rotary compressor 3 configured as described above, the gas compressed by the compression mechanism 9 is discharged from the discharge port 29 to the space 43 in the closed case via the muffler 37. In this operation, when the compressed gas is discharged from the discharge port 29, the noise is attenuated in the muffler 37. On the other hand, since the primary resonance frequency in the muffler 37 does not match the secondary resonance frequency in the closed case space 43, amplification of the resonance does not occur, and noise can be reduced.

FIG. 8 is a diagram showing the noise level in this embodiment. The horizontal axis shows the frequency, and the vertical axis shows the sound power level (dB value based on the A scale).
Resonance near z (shaded area) is greatly reduced, and the effect is remarkable.

[0036]

As described above, according to the rotary compressor of the present invention, since the resonance frequency in the muffler does not match the resonance frequency in the space inside the closed case, noise due to resonance can be reduced. At the same time, vibration noise caused by resonance can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an entire rotary compressor according to the present invention.

FIG. 2 is an explanatory diagram showing a first-order resonance mode in a space inside a closed case.

FIG. 3 is an explanatory diagram showing a secondary resonance mode in a space inside a closed case.

FIG. 4 is an explanatory diagram showing a first-order resonance mode in a muffler.

FIG. 5 is an explanatory diagram in which a dead volume is provided in a part of the muffler.

FIG. 6 is an explanatory view in which a dead volume is integrally formed with a muffler.

FIG. 7 is an explanatory view in which a dead volume is provided integrally on a main bearing member side.

FIG. 8 is an explanatory diagram showing a noise reduction effect that resonates.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing case 7 Electric mechanism part 9 Compression mechanism part 29 Discharge port 37 Muffler 43 Space in sealed case

Claims (8)

[Claims] An air conditioner includes a compression mechanism provided with a muffler, and an electric mechanism for applying rotational power to the compression mechanism. The gas compressed by the compression mechanism is discharged from a discharge port through the muffler. In a rotary compressor that discharges air into a sealed case, a resonance frequency in the muffler and a resonance frequency in a space inside the sealed case formed between the compression mechanism and the electric mechanism are made to be different from each other. Rotary compressor. 2. The method according to claim 1, wherein the first resonance frequency, which is the resonance frequency in the muffler, is set to be substantially intermediate between the first resonance frequency and the second resonance frequency, which are the resonance frequencies in the space inside the closed case. The rotary compressor as described. 3. The muffler is formed in an annular space, and the ratio of the average circumferential length Sc of the space in the closed case to the average circumferential length Sm of the annular space in the muffler is Sm / Sc ≒ 2/3. The rotary compressor according to claim 1, wherein 4. The inside of the muffler is formed in an annular space,
The dead volume is provided in the circumferential direction, and the ratio of the average circumferential length Sc of the space in the closed case to the average circumferential length Sm of the annular space in the muffler is Sm / ScＳ1 / 3. Rotary compressor. 5. The rotary compressor according to claim 4, wherein the dead volume formed in a part in the circumferential direction is formed integrally with the muffler. 6. The rotary compressor according to claim 4, wherein the dead volume is formed by filling a part in the circumferential direction with another member. 7. The rotary compressor according to claim 4, wherein the material forming the dead volume is a sound absorbing material. 8. The rotary compressor according to claim 4, wherein the dead volume is provided integrally with the bearing member and is formed by a projecting portion projecting into the muffler.