JPH03271597A - Vibration damping device for rotary compressor - Google Patents

Abstract

PURPOSE:To reduce the vibration of a rotary compressor efficiently and stably by fixing an inertia member to a connection part so that it can rotate freely around a shaft in parallel with a rotary shaft of a rotary compressor, and eliminating the restriction of bending deformation of the connection part to be caused by the influence of the inertia force of the inertia member. CONSTITUTION:When the refrigerant is compressed in a cylinder 7, since the fluctuation of angular velocity is generated in the rotation of a crank shaft 5, the vibration in the rotating direction around a rotary shaft 14 is generated to vibrate a closed case 2 in the rotating direction. At this stage, an inertia member 16 of a dynamic vibration absorber 15 fixed in the closed case 2 is vibrated in phase with the vibration of the closed case 2 to bend a connection part 18 for deformation with that inertia. The reaction working in the direction reverse to the vibrating direction of the inertia member 16 is therefore generated at a fixation part 2a of the closed case 2 to damp the vibration. Furthermore, since the inertia member 16 of the dynamic vibration absorber 15 is fixed so that it can rotate freely around a center shaft 16d in parallel with the rotary shaft 14, the inertia force works in the direction for rotating the inertia member 16, and does not work in the direction for restricting bending deformation of the connection part 18.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vibration damping device for a rotary compressor used in refrigeration equipment and the like.

2. Description of the Related Art In recent years, compressors used in refrigeration equipment, etc. have been shifting from reciprocating types to rotary types from the standpoint of energy and space saving. These rotary compressors usually have an electric compression element consisting of a compression element section and an electric motor section directly fixed and housed in a sealed case. The rotational vibrations generated around the axis directly vibrate the sealed case, and the vibrations vibrate the main body of the refrigerant piping, freezing and refrigerating equipment, etc., sometimes generating large noise.

Therefore, as a conventional technique for damping the vibrations of a rotary compressor, for example, as shown in Japanese Patent Publication No. 58-5486, a rotary hermetic electric compressor using a beam vibration absorber is proposed. It has a vibration damping structure.

Hereinafter, an example of the vibration damping structure of the conventional rotary compressor mentioned above will be explained with reference to the drawings.

FIGS. 3 to 5 are partial longitudinal and cross-sectional views of a conventional rotary compressor. (In the figure, 1 is a rotary compressor, 2 is a rotary compressor,
is a closed case. 3 is an electric motor, and 3a is a stator of the electric motor, which is fixed in the sealed case 2 by shrink fitting. 3b is a rotor of an electric motor, which is connected and fixed to the crankshaft 5 of the compression element 4 by shrink fitting. A piston 6 is rotatably mounted on the eccentric portion 5a of the crankshaft 5. A cylinder 7 has a lower bearing 8 and an upper bearing 9 disposed at both ends, and its outer circumferential portion is welded and fixed within the sealed case 2. Further, inside the cylinder 7, a compression chamber and a suction chamber are formed by a partition plate (not shown). Reference numeral 10 denotes a discharge cover, which is press-fitted and fixed to the upper bearing 9.

Reference numeral 11 denotes a dynamic vibration absorber, which is composed of an inertial body 12 and a shaft-shaped connecting part 18 that fixes this inertial body 12 to an end 13a. It is fixed to the sealed case 2 by fixing the connecting part 13 to the fixed part 2a by resistance welding so as to be perpendicular to the wall surface.

In addition, the dynamic vibration absorber 11 has a primary natural frequency equal to that of the rotary compressor 1.
The weight and shape of the inertial body 12, the length of the connecting portion 13, the diameter of the cross section, etc. are adjusted so as to match the rotational frequency or the power supply frequency.

14 is a rotation axis.

The operation of the vibration damping device for a rotary compressor that has been subjected to the above-mentioned precautions will be described below.

When compressing the refrigerant in the cylinder 7, the pressure in the compression chamber in the cylinder 7 changes greatly during one revolution of the crankshaft 5, which causes a change in the angular velocity of the rotation of the crankshaft 5, and as a reaction, the cylinder 7 receive power from etc. Therefore, vibrations occur in the rotational direction around the rotating shaft 14, and the sealed case 2 vibrates in the rotational direction.

However, since the dynamic vibration absorber 11 is adjusted so that the primary natural frequency almost matches the rotation frequency or power supply frequency of the rotary compressor 1, the inertia of the dynamic vibration absorber 11 fixed to the sealed case 2 The body 12 vibrates in the same phase as the vibration of the closed case 2, and the connecting portion 18 bends and deforms due to the inertia of the inertial body 12. Therefore, a reaction force is generated in the fixed portion 2a of the sealed case 2 in a direction opposite to the vibration direction of the inertial body 12, and the vibration is damped by the reaction force.

Problems to be Solved by the Invention However, as shown in FIGS. 4 and 5, the dynamic vibration absorber 1
1 is installed inside a sealed case 2, and the shape of the inertial body 12 is such that the mass distribution in the tangential direction of a circle centered on the rotation axis of the rotary compressor 1 is larger than the mass distribution in the radial direction of this circle. In this case, the inertial force of the inertial body 12 caused by vibrations in the rotational direction of the rotary compressor 1 also acts largely in the rotational direction around the center of gravity of the inertial body 12. Therefore, the bending deformation of the connecting portion 13 is suppressed, and a sufficient reaction force cannot be obtained, so that vibrations of the rotary compressor cannot be sufficiently damped in some cases.

In view of the above-mentioned problems, the present invention aims to suppress the decrease in the amount of vibration damping caused by the shape of the inertial body, and efficiently reduce the vibration of a rotary compressor.

Means for Solving the Problems In order to solve the above problems, the vibration damping device for a rotary compressor of the present invention is a rotary type compressor in which an electric motor section and a compression element section driven by the electric motor section are fixedly housed in a sealed case. In the compressor, an inertial body having a shape such that the mass distribution in the tangential direction of a circle centered on the rotational axis of the rotary compressor is larger than the mass distribution in the radial direction of this circle, and the inertial body and the compressor main body. a dynamic vibration absorber formed by a connecting portion that connects with the rotary compressor, and wherein the inertial body is fixed to the connecting portion so as to be rotatable within a certain range around an axis parallel to the rotation axis of the rotary compressor. It is equipped with the following.

Effect of the present invention is as follows: Even when the dynamic vibration absorber is installed inside a sealed case, vibrations in the rotational direction of the rotary compressor are generated and act in the rotational direction around the center of gravity of the inertial body. It is possible to eliminate the suppression of bending deformation of the connecting part due to the influence of the inertial force of the inertial body, prevent a decrease in the reaction force of the dynamic vibration absorber against rotational vibration, and prevent excessive vibration in the direction of rotation of the inertial body, increasing efficiency. This makes it possible to reduce the vibrations of a rotary compressor in a highly stable manner.

Embodiment Hereinafter, an embodiment of the vibration damping device for a rotary compressor according to the present invention will be described with reference to the drawings.

In order to avoid duplication of explanation, the same parts as in the conventional example are given the same reference numerals and the explanation will be omitted.

1 and 2 show an embodiment of a vibration damping device for a rotary compressor according to the present invention.

In the figure, reference numeral 15 denotes a dynamic vibration absorber, which has a substantially U-shape that is shorter in the radial direction than in the tangential direction of a circle centered on the rotation axis 14, and the rotation axis 14 and the center axis 16d are parallel to the approximate center of gravity. An inertial body 16 having a hole 16a. A fixture 17 having a cylindrical bottle 17a that is inserted into the hole 16a and rotatably fixed around the central axis 16d of the hole 16a; a shaft-shaped connecting portion 18 fixed to the fixture 17 at an end 18atl; It is composed of. 16b and 16c are convex portions provided near the hole 16a, and 17C is a convex portion provided near the hole 16a.
This is a protrusion provided on the tip 17b of the protrusion so as to be located between these two protrusions 16b and 16c. These convex portions 16b, 16c and the protrusion 17c allow the rotational movement of the inertial body 16 around the central axis 16d to be controlled by the convex portion 16b.
, 16c are in contact with the protrusion 17c. Roughly, the dynamic vibration absorber 15 is connected to the other end 1 of the connecting portion 18.
8b is mounted inside the sealed case 2 by fixing it to the fixed part 2a of the sealed case 2 by resistance welding so that the connecting part 18 is perpendicular to the wall surface.

Furthermore, the dynamic vibration absorber 15 has an inertial body 16. The weight and shape of the fixture 17, the length of the connecting portion 17, the diameter of the cross section, etc. are adjusted.

The operation of the vibration damping device for a rotary compressor configured as described above will be described below.

When compressing the refrigerant in the cylinder 7, the pressure in the compression chamber in the cylinder 7 changes greatly during one revolution of the crankshaft 5, which causes a change in the angular velocity of the rotation of the crankshaft 5, and as a reaction, the cylinder 7 receive power from etc. Therefore, vibrations occur in the rotational direction around the rotating shaft 14, and the sealed case 2 vibrates in the rotational direction.

At that time, the dynamic vibration absorber 15 is adjusted so that the first natural frequency almost matches the rotational frequency or power frequency of the rotary compressor 1, so the dynamic vibration absorber 15 fixed to the sealed case 2 is The inertial body 16 vibrates in the same phase as the vibration of the sealed case 2, and the connecting portion 18 is bent and deformed due to the inertia of the inertial body 16. Therefore, a reaction force is generated in the fixed portion 2a of the sealed case 2 in a direction opposite to the vibration direction of the inertial body 16, and the vibration is damped by the reaction force.

Furthermore, since the inertial body 16 of the dynamic vibration absorber 15 is fixed so as to be rotatable around the central axis 16d parallel to the rotating shaft 14, the inertial body 16 is generated by vibrations in the rotational direction of the rotary compressor 1. The inertial force acting in the direction of rotation around the center of gravity of the body 16 acts in the direction of rotating the inertial body 16, but does not act in the direction of suppressing bending deformation of the connecting portion 18. Therefore, the bending deformation of the connecting portion 18 is not suppressed, and the reaction force generated by the bending deformation of the connecting portion 18 does not decrease significantly, so that vibrations of the rotary compressor 1 can be efficiently reduced.

Moreover, due to the protrusions 16b and 16c provided on the inertial body 16 and the protrusion 17c provided on the bottle 17a of the fixture 17, the rotational movement of the inertial body 16 around the central axis 16d is controlled by the protrusions 16b and 16c. Since the vibration is limited to the range in contact with the portion 17c, excessive amplitude in the rotational direction of the inertial body 16 can be prevented, and stable vibration reduction of the rotary compressor can be achieved.

Effects of the Invention As described above, the vibration damping device of the present invention provides a rotary compressor in which an electric motor section and a compression element section driven by the electric motor section are fixedly housed in a sealed case. is formed by an inertial body having a shape such that the mass distribution in the tangential direction of a circle centered on is larger than the mass distribution in the radial direction of this circle, and a connecting part that connects this inertial body and the compressor main body, and By providing a dynamic vibration absorber fixed to the connecting part so that the body can freely rotate within a certain range around an axis parallel to the rotation axis of the rotary compressor, the inertial body is centered near the center of gravity. This eliminates the suppression of bending deformation of the connecting part caused by inertial force acting in the rotational direction, and prevents a reduction in the reaction force of the dynamic vibration absorber against rotational vibration, as well as preventing over-amplitude of the inertial body in the rotational direction. , it is possible to efficiently and stably reduce vibrations of a rotary compressor.

[Brief explanation of drawings]

Figure 1 is a vertical sectional view of a rotary compressor equipped with a vibration damping device according to an embodiment of the present invention, Figure 2 is a horizontal sectional view of the same compressor, and Figure 3 is a conventional vibration damping device installed. FIG. 4 is a vertical sectional view of another conventional rotary compressor, and FIG. 5 is a horizontal sectional view of the same compressor. 2... Sealed case, 15... Dynamic vibration absorber, 16...
Inertial body, 17... Fixture, 18. Connecting part.

Claims (1)

[Claims] In a rotary compressor in which an electric motor section and a compression element section driven by the electric motor section are fixedly housed in a sealed case, the mass distribution in the tangential direction of a circle centered on the rotation axis of the rotary compressor is as follows. It is formed by an inertial body having a shape larger than the mass distribution in the radial direction of a circle, and a connecting part that connects this inertial body and the compressor main body, and the inertial body is connected to the connecting part of the rotary compressor. A vibration damping device for a rotary compressor equipped with a dynamic vibration absorber that is fixed so that it can rotate freely within a certain range around an axis that is parallel to the rotation axis.