JP2553642B2 - Vibration damping device for rotary compressor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping device for a rotary compressor used in a refrigerating machine or the like.

2. Description of the Related Art In recent years, compressors used for refrigerating and refrigerating equipment have changed from a reciprocating type to a rotary type from the viewpoint of energy saving and space saving, and a beam type dynamic vibration reducer is used as a vibration damping device for the rotary type compressor. It is used. As a conventional technology,
As disclosed in Japanese Patent Laid-Open No. 58-5486, there is a vibration damping structure for a rotary hermetic electric compressor.

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

FIG. 2 is a partial cross section of a conventional rotary compressor. In the figure, 1 is a rotary compressor, and 2 is a closed case. Three
Is a stator of a motor, which is shrink-fitted and fixed to the closed case 2. Reference numeral 4 denotes a motor rotor, which is connected and fixed to the crankshaft 5 by a shrink fit. 6 is a piston,
It is rotatably fixed to the eccentric part of the crankshaft 5. Reference numeral 7 is a cylinder, and a lower bearing 8 and an upper bearing 9 are arranged at both ends, and the outer peripheral portion is welded and fixed to the sealed case 2. A discharge cover 10 is press-fitted and fixed to the upper bearing 9. Reference numeral 11 denotes a beam type dynamic vibration reducer, which includes an inertial body 12 and this inertial body.
12 is formed by a shaft-shaped connecting portion 13 provided at an end portion 13a, and the other end portion 13b of the connecting portion 13 is fixed by resistance welding in a direction perpendicular to the wall surface of the closed case 2.
The beam type dynamic vibration reducer 11 supports the natural vibration of the support system of the rotary compressor 1 itself by supporting and fixing the rotary type compressor 1, and the primary natural vibration of the beam type dynamic vibration reducer 11. The weight and shape of the inertial body 12, the length of the connecting portion 13 and the diameter of the cross section are adjusted so that the maximum damping frequency generated by the coupling substantially matches the rotation frequency of the rotary compressor 1.

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

When the refrigerant is compressed in the cylinder 7, the pressure of the cylinder 7 greatly changes during one rotation of the crankshaft, which causes a change in the angular velocity in the rotation of the crankshaft 5, and as a reaction thereof, a force is applied to the cylinder 7 and the like. receive. As a result, vibration occurs in the rotational direction about the axis of the crankshaft 5, causing the sealed case 2 to vibrate greatly. However, the natural frequency is adjusted so that the maximum damping frequency substantially matches the rotation frequency of the rotary compressor 1, and the closed case 2
The inertial body 12 of the beam type dynamic vibration reducer 11 installed in the
By vibrating in the opposite phase to the vibration of
Is a beam-type dynamic vibration reducer at the installation location in the closed case 2.
The reaction torque is supplied to the closed case 2 via the connecting portion 13 of the above, and the vibration is damped.

However, with the above-mentioned configuration, the beam type dynamic vibration reducer 11
Since the peak (Q value) of the natural frequency is sharp, the peak (Q value) of the maximum damping frequency generated by the coupling with the natural vibration of the support system of the rotary compressor 1 itself is also sharp. Therefore, when the maximum damping frequency and the rotation frequency of the rotary compressor 1 match, the damping effect is extremely large, but the change of the rotation frequency due to the change of the operating condition of the rotary compressor 1 and the dynamic vibration absorber 11 of the beam type. Due to a change in natural frequency due to variations in manufacturing, etc., the maximum damping frequency generated by the coupling with the natural vibration of the support system of the rotary compressor 1 itself changes,
When the frequency difference between the maximum damping frequency and the rotation frequency of the rotary compressor 1 becomes large, the vibration damping effect becomes insufficient.

Further, since the end portion 13b of the connecting portion 13 is concentrated in stress due to the deformation of the connecting portion 13, the end portion 13b may be broken due to fatigue due to vibration or impact.

In view of the above-mentioned problems, the present invention prevents fluctuations in the rotation frequency of the rotary compressor 1 and a reduction in the vibration damping effect due to variations in manufacturing, etc., and also destroys the beam dynamic vibration reducer 11 due to fatigue and shock due to vibration. Is to prevent.

Means for Solving the Problems In order to solve the above problems, a vibration damping device for a rotary compressor according to the present invention has a hermetically sealed case in which an electric motor section and a compression element section are fixedly housed. It is provided with a coil-shaped connecting portion and an inertial body fixed to the other end of the connecting portion.

Effect of the Invention With the above-described configuration, the present invention provides the rotary compressor in which the inertial body, which is fixed to the tight coil-shaped connecting portion fixed to the outer peripheral portion of the hermetically sealed case of the rotary compressor, vibrates during operation of the rotary compressor. By vibrating in a phase opposite to that of the vibration, the reaction torque is supplied to the rotary compressor to dampen it, and the connecting part between the closed case and the inertial body is coiled to fix it to the closed case. In addition to reducing the stress caused by the vibration of the end of the connecting part and the deformation caused by impact, the damping effect due to the contact surfaces of the connecting part being rubbed by the vibration is obtained and the peak width of the natural frequency of the inertial body is wide. (Increases Q value), and by placing an inertial body on the outer peripheral part of the closed case, the inertia moment becomes larger than when it is placed on the inner peripheral part of the closed case. A dynamic damping effect is obtained.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. To avoid duplication of description, the same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 shows an embodiment of a vibration damping device for a rotary compressor according to the present invention. In the figure, 14 is a dynamic vibration absorber,
The inertial body 15 and the coil-shaped spring 16 closely attached to each other are used as a connecting portion. The spring 16 is installed in the vertical direction with respect to the crankshaft 5 and the end portion 16a is fixed to the hermetically sealed case 2 with a screw 1
The other end portion 16b is fitted and fixed to a screw (not shown) fixed to the inertial body 14.

Further, the dynamic vibration reducer 14 is configured so that the maximum damping frequency generated by the coupling between the natural frequency of the support system of the rotary compressor and the natural frequency of the dynamic vibration reducer 14 substantially matches the rotation frequency of the compressor 1. The shape of the spring 16 and the weight and shape of the inertial body 15 are adjusted.

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

When the refrigerant is compressed in the cylinder 7, the pressure in the cylinder 7 greatly changes during one rotation of the crankshaft 5, which causes a change in the angular velocity in the rotation of the crankshaft 5, and as a reaction thereof, the cylinder 7 and the like are affected. Receive power.
As a result, vibration occurs in the rotational direction about the axis of the crankshaft 5, causing the sealed case 2 to vibrate greatly.
At that time, the maximum damping frequency generated by the combination of the natural vibration of the dynamic vibration reducer 14 installed in the closed case 2 and the natural vibration of the support system of the rotary compressor 1 itself substantially matches the rotation frequency of the rotary compressor 1. Since it is adjusted to
The inertial body 14 of 14 vibrates in the opposite phase to the vibration of the closed case 2. Therefore, the spring 16 of the dynamic vibration reducer 14 and the closed case 2
A reaction torque is supplied to the closed case 2 via the screw 17 fixed to the closed case 2 to damp the vibration of the closed case 2.

Furthermore, by forming the spring 16 into a coil shape in close contact, a damping effect for rubbing the surfaces of the spring 16 in contact with each other due to vibration is obtained, and the width of the peak of the natural frequency of the dynamic vibration reducer 14 is widened (Q value is growing). for that reason,
Since the peak width of the maximum damping frequency generated by the combination of the natural vibration of the dynamic vibration reducer 14 and the natural vibration of the support system of the rotary compressor 1 becomes wide (the Q value becomes large), the vibration is damped in a wide frequency band. Even if there is a change in the rotation frequency due to a change in the operating conditions of the rotary compressor 1 or a change in the maximum damping frequency caused by the variation in the natural frequency during mass production of the beam type dynamic vibration absorber, it is sufficient. A vibration damping effect can be obtained.

Further, by forming the spring 16 into a coil shape, the stress at the end portion 16a for the same displacement is smaller than that of a beam having the same material and the same diameter, and fatigue due to vibration or stress due to impact can be reduced. It is possible to prevent the end portion 16a from breaking due to vibration or impact, and improve the reliability of the dynamic vibration reducer 14. It should be noted that the same effect can be obtained by similarly fixing the end portion 16a of the spring 16 to the compression element portion instead of the closed case 2, but the vibration damping effect is reduced.

EFFECTS OF THE INVENTION As described above, according to the present invention, a tight coil-shaped connecting portion having one end fixed to the outer peripheral portion of the hermetically sealed case in which the electric motor portion and the compression element portion are fixedly housed and the other end portion of the connecting portion are fixed. By including the inertial body, the vibration generated during the operation of the rotary compressor is effectively dampened and the damping effect of the vibration of the dynamic vibration absorber is provided, so that the operating conditions of the rotary compressor can be changed or during the manufacturing. The vibration damping effect can be sufficiently obtained even if there are variations, etc., and the dynamic vibration absorber can be prevented from being damaged by vibration or impact, and stable vibration reduction of the rotary compressor can be achieved.

[Brief description of drawings]

FIG. 1 is a sectional view of a vibration damping device for a rotary compressor showing an embodiment of the present invention, and FIG. 2 is a sectional view of a vibration damping device for a conventional rotary compressor. 2 ... Hermetically sealed case, 14 ... Dynamic vibration absorber, 15 ... Inertia, 16
……Spring.

Claims (1)

(57) [Claims] 1. A close contact coil-shaped connecting portion having one end fixed to an outer peripheral portion of a hermetically sealed case in which an electric motor portion and a compression element portion are fixedly housed, and an inertial body fixed to the other end of the connecting portion. Vibration reduction device for rotary compressor.