JPH03271596A - Vibration damping device for rotary compressor - Google Patents

Abstract

PURPOSE:To reduce a lowering quantity of the reaction of a dynamic vibration absorber against the rotational vibration, and reduce the vibration of a rotary compressor efficiently by reducing the inertia force working in the rotating direction nearly around the center of gravity of an inertia member to reduce a restriction quantity of bending deformation of a connection part. 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, and a closed case 2 is rotated 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, and since a connection part 13 is fending deformed by that inertia, the reaction is generated at a fixation part 2a of the closed case 2 to damp the vibration. Furthermore, since the mass distribution in the tangent direction of a circle around the rotary shaft 14 is smaller than the mass distribution in the radial direction of that circle, the inertia force of the inertia member 16 working in the rotational direction nearly around the center of gravity of the inertia member 16 is small, and a restriction quantity of bending deformation of the connection part 13 is reduced.

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 and the like generated around the centrifuge directly vibrate the closed case, and the vibrations sometimes vibrate the main body of the refrigerant piping, freezing and refrigeration equipment, etc., and generate 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 a partial vertical sectional view and a horizontal sectional view of a conventional rotary compressor. In the figure, 1 is a rotary compressor, 2
is a closed case. 3 is an electric motor, and %3JL 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. Also, inside the cylinder 7 is a partition plate (not shown).
A compression chamber and a suction chamber are formed. 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 includes an inertial body 12 and an end portion 1 of the inertial body 12.
3a, and the other end 13b of the connecting portion 13 is connected to the closed case 2.
The connecting part 13 is fixed to the sealed case 2 by resistance welding to the fixed part 2a so as to be perpendicular to the wall surface. In addition, the dynamic vibration absorber 11 has a shape of the inertial body 12, a length of the connecting part 13, a cross-sectional diameter, etc. so that the first natural frequency almost matches the rotational frequency or the power supply frequency of the rotary compressor 1. It is adjusted. 14 is a rotation axis.

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 fluctuates widely during one rotation of the crankshaft 5, causing a fluctuation in the angular velocity of the rotation of the crankshaft 5, and as a reaction, the cylinder Receives force from 7th magnitude. 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 13 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 rotation axis of the rotary compressor is smaller than the mass distribution in the radial direction of this circle, and this inertia with respect to the rotation axis It is equipped with a dynamic vibration absorber consisting of a connecting part that is internally fixed to the closed case at the outer periphery from the center of gravity of the body.

Effect of the present invention is based on the above-mentioned item 11. 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. By reducing the inertial force of the inertial body, the vibration of the rotary compressor can be efficiently reduced.

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 includes an inertia body 16 having a substantially U-shape in which the cross section of the plane perpendicular to the rotation axis 14 is longer in the radial direction than in the tangential direction; The shaft-like connecting part 17 has an inertial body 16 fixed to an end 17a, and the other end 17b of the connecting part 17 is connected to the fixed part 2a of the sealed case 2, and the connecting part 17 is perpendicular to the wall surface. By fixing with resistance welding,
It is installed inside the sealed case 2.

In addition, the dynamic vibration absorber 15 is designed so that its primary natural frequency almost matches the rotational frequency or power supply frequency of the rotary compressor 1, the weight and shape of the inertial body 16, the length of the connecting portion 17,
Adjust the cross-sectional diameter, etc.

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 inertia of the inertial body 12 bends and deforms the connecting portion 13. 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. Furthermore, since the inertial body 16 of the dynamic vibration absorber 15 has a substantially U-shaped cross section on a surface perpendicular to the rotating shaft 14, which is longer in the radial direction than in the tangential direction of the circle centered on the rotating shaft 14, The mass distribution in the tangential direction of a circle centered on the rotating shaft 14 is smaller than the mass distribution in the radial direction of this circle. Therefore, the rotating shaft 14
Compared to the case of an inertial body whose mass distribution in the tangential direction of a circle centered on Since the inertial force acting in the rotational direction around the center is small, the amount of suppression of bending deformation of the connecting portion 13 is reduced, and the amount of reduction in reaction force is also reduced, it is possible to efficiently reduce the vibration of the rotary compressor. can.

Effects of the Invention As described above, 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. An inertial body having a shape in which the mass distribution in the tangential direction of a circle is smaller than the mass distribution in the radial direction of the circle, and a connection that is inscribed and fixed to the closed case at the outer periphery of the inertial body from the center of gravity position with respect to the rotation axis. By providing a dynamic vibration absorber consisting of a portion, the inertial force acting in the direction of rotation around the center of gravity of the inertial body is reduced, and the amount of suppression of bending deformation of the connecting portion 13 is reduced. Since the amount of decrease in the reaction force of the compressor can be reduced, it is possible to efficiently reduce the vibration of the rotary compressor.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a rotary compressor equipped with a vibration damping device according to an embodiment of the present invention, FIG. 2 is a horizontal sectional view of the same compressor, and FIG. 3 is a conventional vibration range. 2... Sealed case, 15... Dynamic vibration absorber, 16...
Inertial body, 17... connection 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. A dynamic vibration absorber comprising an inertial body having a shape smaller than the mass distribution in the radial direction of a circle, and a connecting part that is inscribed and fixed in a sealed case at an outer periphery of the inertial body from the center of gravity of the inertial body with respect to the rotation axis. Vibration damping device for rotary compressors.