JPH1037884A - Noise suppresser for rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lowly retain a noise level under wide operating conditions by effectively damping a plurality of pressure pulsation components which exerts especially large influence upon a noise. SOLUTION: A space 21a and a space 21b being a noise suppresser communicated with a compression chamber, which have length corresponded to 1 wavelength and 3/4 wavelength of resonance wavelength, are formed on the cylinder contact surface of a lower bearing 5 by differing positions form each other. Both spaces 21a, 21b are formed by recognizing a vane as a reference point while keeping angles (θ2 , θ2 ) respectively satisfying formulae, θ1 =360 deg.× 1-v/2fRπ)}, and θ2 =360 deg.× 1×3v/(8fRπ)} (wherein (v) represents a refrigerant gas sonic velocity, (f) represents structural resonance frequency, and R represents the radius of a cylinder bore).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary compressor, and more particularly to a rotary compressor silencer suitable for reducing high-frequency noise generated in a cylinder during operation.

[0002]

2. Description of the Related Art Research on lowering the high-frequency noise level of a rotary compressor has been carried out for a long time, but there are still problems that have not been solved. It is considered that the main source of the noise is the pressure pulsation generated in the compression chamber. This pressure pulsation component is a standing wave determined by the shape of the compression chamber formed by the cylinder, the roller, and the upper and lower bearings. For this reason, when a pulsation component of the resonance frequency of the compressor structure system occurs in the compression chamber due to the compression chamber shape at a certain timing during the compression stroke, the noise level becomes extremely high.

[0003] Attempts to reduce such pressure pulsations include:
For example, it is known that a pocket portion (space) is provided at a predetermined position so as to communicate with a compression chamber in a cylinder to absorb a pulsation component (see Japanese Patent Publication No. 7-26633).

[0004]

Among the pressure pulsation components of the rotary compressor, those having a high sound pressure level and being annoying as noise are the one-wavelength component and the three-quarter wavelength component of the resonance frequency of the structural system. If these wavelength components can be attenuated by some method, other high-frequency noises remain, but can be avoided to some extent.

[0005] Conventionally, due to the space that communicates with the compression chamber, the noise level is reduced under a limited compression ratio, and a sufficient noise reduction effect is obtained. Instead, unpleasant sounds may remain on some parts.

Also, the silencer is insufficient to maintain the desired noise level under a wide range of compression ratios.

Accordingly, an object of the present invention is to provide a rotary compressor which effectively attenuates a plurality of pressure pulsation components which have a particularly large effect on noise and maintains the noise level low under a wide range of operating conditions. It is to provide a silencer.

[0008]

In order to achieve the above object, the present invention comprises a vane extending and retracting in the radial direction of a cylinder, wherein the tip of the vane slides on a roller which slides on the cylinder, and a suction chamber is formed in the cylinder. And a rotary compressor configured to partition into a compression chamber, the upper and lower ends of the cylinder or the cylinder contact surface of the upper and lower bearings that seal the upper and lower ends of the cylinder. A plurality of spaces each having a length corresponding to one wavelength and a 波長 wavelength component of the resonance frequency communicating with the compression chamber in the cylinder are provided, and each space has an angle (θ1, θ2) satisfying the following equation with the vane as a base point. ) Is arranged so as to be open to the compression chamber in the cylinder.

Θ1 = 360 ゜ × {1-v / (2fRπ)} (1) θ2 = 360 ゜ × {1 × 3v / (8fRπ)} (2) where, v: refrigerant gas Sound velocity f: Structural resonance frequency R: Cylinder bore radius

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2, a cylinder 2 is provided at a lower part in a closed container 1. A shaft 3 is provided through the cylinder 2 and along the axis of the closed casing 1. The shaft 3 is rotatable by an upper bearing 4 and a lower bearing 5 which seal the upper and lower ends of the cylinder 2. It is supported. Further, an annular roller 6 is mounted on a pin portion of the shaft 3 facing the inside of the cylinder 2.

Further, the cylinder 2 is provided with a suction passage 8 connected to a suction pipe 7 for guiding a low-temperature, low-pressure refrigerant gas into the chamber. This communicates with a suction chamber formed in the cylinder 2 described later. A discharge port 11 is formed in the upper bearing 4 so that a compression chamber described later formed in the cylinder 2 communicates with a discharge space 10 defined by the discharge muffler 9 and the inside of the closed container 1. This outlet 11
Is provided with a discharge valve 12.

On the other hand, a motor 13
Is provided. The motor 13 includes a stator core 14 and a rotor core 15, and a shaft 3 extending to the center of the rotor core 15 is fixed to the rotor core 15, and the motor 1
The roller 6 slides in the cylinder 2 in accordance with the rotation of the roller 5. Further, a discharge pipe 16 for guiding a high-temperature, high-pressure refrigerant gas in the vessel to the outside is provided at an upper portion of the closed vessel 1.

Further, the cylinder 2 of the present embodiment has a silencer 17 which will be described later in detail with reference to the drawings. In the present embodiment, the silencer 17 is formed on the lower bearing 5 that seals the lower end of the cylinder 2.

FIG. 3 shows a cross section of the cylinder 2 on which the roller 6 slides. A vane 18 is provided slidably in the radial direction toward the outer peripheral surface of the roller 6 mounted on the pin portion of the shaft 3. The tip of the vane 18 extends to a position where the vane 18 can slide on the roller 6, so that the interior of the cylinder 2 is partitioned into a suction chamber 19 and a compression chamber 20 during operation.

FIGS. 1A and 1B show a muffler 17 communicating with a compression chamber 20. FIG. A space 21 having a length corresponding to one- and three-quarter wavelength components of a resonance frequency of a structural system as a silencer that communicates with the compression chamber 20 at different positions on the cylinder contact surface of the lower bearing 5.
a and a space 21b are formed. Both spaces 21
a and 21b are formed keeping the angles (θ1, θ2) satisfying the following equation with the vane 18 as a base point.

Θ1 = 360 ゜ × {1-v / (2fRπ)} (1) θ2 = 360 ゜ × {1 × 3v / (8fRπ)} (2) where, v: refrigerant gas Sound velocity f: Structural resonance frequency R: Cylinder bore radius

Equation (1) shows the position of the space 21a which attenuates one wavelength component of the resonance frequency of the structural system among the pressure pulsation components, and equation (2) shows 3/3 of the resonance frequency of the same structural system. The position of the space 21b that attenuates the four wavelength components is shown.

In the above configuration, when the roller 6 in the cylinder 2 rotates in the direction shown by the arrow in FIG. 3 due to the rotation of the motor 13, the refrigerant gas enters the suction chamber 19 through the suction passage 8 and is further compressed in the compression chamber 20. , A discharge port 11, a discharge valve 12, and a passage (not shown) in the motor 13 from the discharge pipe 16 to the outside.

At this time, the low-temperature, low-pressure refrigerant gas sucked into the suction chamber 19 starts to be compressed from the position where the roller 6 starts to close the suction passage 8 of the cylinder 2, and the volume of the compression gas in the compression chamber 20 gradually decreases. And becomes a high-temperature, high-pressure refrigerant gas.

At this time, a space 21 having a predetermined length (volume) as a silencer opening into the compression chamber 20 is provided.
a, 21b are filled with a high-temperature, high-pressure refrigerant gas. Among the pulsation components, one wavelength component is absorbed in the space 21a by the side branch effect and is effectively attenuated. Similarly, 3 /
The four wavelength components are absorbed in the space 21b by the side branch effect, and are similarly attenuated.

FIG. 4 shows how the noise level decreases.
(A). For comparison, FIG. 4B also shows the noise level when the silencer of the present embodiment is not used. As can be seen from FIG.
The 波長 wavelength components are both attenuated, and are reduced to such a degree that they are hardly noticeable as noise.

The spaces 21a and 21b formed at an angle determined for each one-wavelength component and three-quarter wavelength component of the resonance frequency of this structural system not only attenuate a specific pressure pulsation component but also have a wide range of compression. An excellent silencing effect can be obtained under the ratio.

Although the silencer is provided in the lower bearing 5 in the above embodiment, if the same volume can be ensured, the equation (1)
The silencer may be provided at an angle suitable for (2).
Further, similar silencers may be formed at the upper and lower ends of the cylinder 2.

[0024]

As described above, according to the present invention, the space opened to the compression chamber can be either the upper and lower ends of the cylinder or the cylinder contact surfaces of the upper and lower bearings which seal the upper and lower ends of the cylinder. The surface is formed at an angle determined for each one- and three-quarter wavelength component of the resonance frequency of the structural system, so that pressure pulsation components that have a particularly large effect on noise can be reliably attenuated. It is possible to reduce high-frequency noise under a wide range of compression ratios.

[Brief description of the drawings]

FIG. 1A is a perspective view showing an embodiment of a muffler according to the present invention. (B) is a layout view showing a muffler according to the present invention.

FIG. 2 is a sectional view showing a rotary compressor according to the present invention.

FIG. 3 is a sectional view of a cylinder portion of the rotary compressor shown in FIG. 2;

FIG. 4 (a) is a graph showing a noise level when the noise reduction device according to the present invention is used. (B) is a graph which shows the noise level when a silencer is not used.

[Explanation of symbols]

 2 Cylinder 3 Shaft 4 Upper bearing 5 Lower bearing 6 Roller 18 Vane 19 Suction chamber 20 Compression chamber 21a, 21b Space

Claims (1)

[Claims] A vane is provided which protrudes and retracts in a radial direction of a cylinder, and a tip end of the vane is slidably contacted with a roller which slides on the cylinder, thereby partitioning the inside of the cylinder into a suction chamber and a compression chamber. In the rotary compressor, any one of the cylinder contact surfaces of the upper and lower bearings sealing the upper and lower ends of the cylinder or the upper and lower ends of the cylinder communicates with the compression chamber in the cylinder. A plurality of spaces having a length corresponding to one wavelength and a 波長 wavelength component of the resonance frequency are provided, and the spaces maintain the angles (θ1, θ2) satisfying the following equations with the vane as a base point. A muffler for a rotary compressor, wherein the muffler is arranged so as to open to the compression chamber in a cylinder. θ1 = 360 ゜ × {1-v / (2fRπ)} (1) θ2 = 360３ × {1 × 3v / (8fRπ)} (2) where, v: refrigerant gas sound velocity f: Structural system resonance frequency R: Cylinder bore radius