JPH0240093A - Vibration damping device for rotary compressor - Google Patents

Abstract

PURPOSE:To keep off any drop in a vibration damping effect by notching a thread ridge end at the connecting side of a screw part formed in a compression element part or an inertial body on an axial section. CONSTITUTION:Reaction torque is fed to a closed case 2 via a screw 17 clamped to a spring 16 of a dynamic vibration reducer 14 and this closed case 2, and thereby vibration in the closed case is damped. The spring 16 is formed in a coil form closely stuck, whereby a surface in contact with the spring 16 each is rubbed by vibrations so that a damping effect is securable, thus natural frequency in the dynamic vibration reducer 14 is widened in terms of its peak width. In addition, thread ridge ends 17a, 18a of the screws 17, 18 are notched on an axial section passing through a shaft of a thread part, whereby positioning of a clamp end of the spring 16 is carried out so that stabilization for a spring constant is thus promoted.

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.

BACKGROUND OF THE INVENTION In recent years, compressors used in refrigeration equipment, etc. have shifted from reciprocating type to two-vane rotary type from the viewpoint of energy saving and space saving. A vibration absorber is used. As a conventional technique, for example, there is a vibration damping structure for a rotary hermetic electric compressor, as disclosed in Japanese Patent Publication No. 58-5486.

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

FIG. 3 is a partial cross-section of a conventional rotary compressor.

In the figure, 1 is a rotary compressor, and 2 is a closed case. 3 is a stator of the motor, which is fixed to the sealed case 2 by shrink fitting. Reference numeral 4 denotes a rotor of the motor, which is connected and fixed to the crankshaft 5 by a shrink fit. A piston 6 is rotatably fixed to the eccentric portion of the crankshaft 5.

7 is a cylinder with lower bearings 8 at both ends. An upper bearing 9 is provided, and its outer peripheral portion is welded and fixed to the sealed case 2. 1
0 is 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 portion 13 with the inertial body 12 provided at an end 13-a. The other end 13b is fixed by welding.

Furthermore, the dynamic vibration absorber 11 supports and fixes the rotary compressor 1, and this is caused by the coupling of the natural vibration of the support system of the rotary compressor 1 itself and the primary natural vibration of the dynamic vibration absorber 11. The weight and shape of the inertial body 12 and the connection portion 13 are adjusted so that the maximum damping frequency substantially matches the rotational frequency of the rotary compressor 1.

The diameter of the cross section is adjusted to π, X].

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 cylinder 7 fluctuates greatly during one revolution of the crankshaft, causing a fluctuation in angular velocity during 50 revolutions of the crankshaft, and as a reaction, force is applied to the cylinder 7, etc. . Therefore, vibrations occur in the rotational direction around the axis of the crankshaft 5, and the sealed case 2 vibrates greatly. However, by adjusting the natural frequency so that the maximum damping frequency almost matches the rotational frequency of the rotary compressor 1, the inertial body 12 of the dynamic vibration absorber 11 installed in the sealed case 2 causes vibrations opposite to the vibration of the sealed case 2. By vibrating in phase, the dynamic vibration reducer 11 supplies a reaction torque to the closed case 2 via the connecting part 13 of the dynamic vibration absorber 11 at the installation location in the closed case 72,
It dampens vibrations.

Problems to be Solved by the Invention However, in the above configuration, the peak of the natural frequency (Q value) of the dynamic vibration absorber 11 is sharp, and the natural vibration of the support system of the rotary compressor 1 itself is The peak (Q value) of the maximum damping frequency that occurs also becomes sharp. Therefore, if the maximum damping frequency and the rotation frequency of the rotary compressor 10 match, the damping effect is extremely large, but the
Due to changes in the rotational frequency due to changes in the operating conditions and changes in the natural frequency due to variations in the manufacturing process of the dynamic vibration absorber 11, the maximum damping frequency that occurs due to the natural vibration of the support system of the rotary compressor 1 itself due to this coupling. If the difference between the maximum damping frequency and the rotational frequency of the rotary compressor 1 becomes large due to changes in the vibration damping effect, the vibration damping effect may become insufficient.

Further, the end portion 13b of the connecting portion 13 is subject to stress caused by the deformation of the connecting portion 13, so that it may break due to fatigue caused by vibration or impact.

In view of the above-mentioned problems, the present invention prevents the vibration damping effect from decreasing due to fluctuations in the rotational frequency of the rotary compressor 1, manufacturing variations, etc., and also prevents the dynamic vibration absorber 11 from being destroyed due to fatigue and impact due to vibration. It is something to do.

Means for Solving the Problems In order to solve the above problems, the vibration damping effect of the rotary compressor of the present invention can be achieved by using a closed case that fixedly houses the electric conductor section and the compression element section, or by providing the compression element section with a sealed case. A coil-shaped connecting part with one end inserted or fitted into the threaded part along the thread, and an inertial body having a threaded part with the other end of the connecting part inserted or fitted along the thread. The threaded end portion of at least one of these threaded portions on the connecting portion side is cut out on the axial cross section.

67, -7 Effect The present invention has the above-described configuration, so that the dynamic vibration absorber fixed to the rotary compressor body can absorb the vibrations generated during operation of the rotary compressor in a phase opposite to the vibrations of the rotary compressor. By doing so, it is damped by supplying a reaction torque to the rotary compressor, and by making the connection between the sealed case and the inertial body into an angled shape, the connection between the closed case and the fixed joint is reduced. In addition to reducing the stress caused by deformation of the end due to vibration or impact, the threaded end on the connecting part side of the threaded part is notched in the axial cross section. 9. Position the fixed end of the spring to stabilize the spring constant.

EXAMPLE An example of the present invention will be described below with reference to the drawings. Incidentally, 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.

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 reducer,
It is composed of an inertial body 15 and a closely coiled spring 16. The spring '16 is installed perpendicularly to the crankshaft 5, and its end 16a is connected to a screw 1 fixed to the sealed case 2.
7 with 14>2 included, and the other end 16b is fixed to the inertial body 1
4 and is identified by being fitted into the screw 18 fixed thereto.

The screws 17 and 18 have threaded ends 17a18a on the spring 16 side.
The axial section through the axis of the threaded part is cut out at 2'.

Furthermore, the dynamic vibration reducer 14 (the dynamic vibration absorber 14) is set so that the maximum damping frequency generated by the coupling of the natural frequency of the support system of the rotary piezo knitting machine and the natural vibration frequency of the dynamic vibration absorber 14 almost matches the rotational frequency of the compressor 1. In addition, the shape of the spring 16 and the shape of the inertial body 150 are adjusted.

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

Although the refrigerant is compressed in the cylinder 7, the pressure inside the cylinder Y fluctuates greatly during one revolution of the crankshaft 5, causing a fluctuation in the angular velocity of the rotation of the crank shunt 5, and as a reaction, a force is exerted on the cylinder 7, etc. receive. Therefore, vibrations occur in the rotational direction around the axis of the crankshaft 5, and the sealed case 2 vibrates greatly. At that time, the maximum damping frequency caused by the coupling of the natural vibration of the dynamic vibration absorber 14 installed in the sealed case 2 and the natural vibration of the support system of the rotary compressor 1 itself is set to approximately the rotational frequency of the rotary compressor 1. Because it is adjusted to match, the dynamic vibration absorber 14
The inertial body 15 vibrates in the opposite phase to the vibration of the sealed case 2. Therefore, the springs 16 of the dynamic vibration reducer 14 supply a reaction force (-) to the sealed case 2 through the screws 17 fixed to the sealed case 2, thereby damping the vibrations of the sealed case 2.

Furthermore, by making the springs 16 tightly coiled, a damping effect can be obtained that prevents the mutual contact between the springs 16 from rubbing due to vibration, and the width of the peak of the natural frequency of the dynamic vibration absorber 14 is widened ( Q value increases). As a result, the width of the peak of the maximum damping frequency that occurs due to the natural vibration of the dynamic vibration reducer 14 and the natural vibration of the support system of the rotary compressor 1 becomes wider (the Ω value becomes larger), so that it can be used in a wide frequency band. Vibration reduction effect can be obtained. Moreover, screw 17.
By notching the threaded ends 17a and 18a of 18 on the axial cross section passing through the axis of the threaded part, 'J' is determined at the fixed end of the spring 16, and the spring constant can be stabilized, thereby increasing the maximum damping frequency. can be stabilized. Therefore, even if there is a change in the rotational frequency due to a change in the operating conditions of the rotary compressor 1, a sufficient vibration damping effect can be obtained.

In addition, by forming the connecting portion 16 in a coil shape, the end portion 16a is more stable against the same displacement than a beam made of the same material and having the same diameter.
The stress at the end portion 16a is small, reducing fatigue due to vibration and stress due to impact, preventing breakage of the end portion 16a due to vibration or impact, and improving reliability of the dynamic vibration absorber 14. Note that the same effect can be obtained by similarly fixing the end portion 16a of the connecting portion 16 to the compression element portion instead of the closed case 2.

Effects of the Invention As described above, the present invention provides a sealed case in which the electric A8 part and the compression element part are fixedly housed, or 1) one end 101-/ A coil-shaped connecting part into which a part is inserted or fitted, and an inertial body having a threaded part into which the other end of this connecting part is inserted or fitted along the thread, and one of these threaded parts By notching the end of the thread on the connecting part side of at least one threaded part on the axial cross section, the spring can be positioned.This damps the vibrations that occur during operation of the rotary compressor, and also provides a wider damping effect. Since the vibration reduction effect can be obtained in the frequency band and the maximum damping frequency can be stabilized, a sufficient vibration reduction effect can be obtained even if the rotation frequency changes due to changes in the operating conditions of the rotary compressor. In addition, it is possible to prevent the dynamic vibration absorber from being destroyed due to vibration or impact, and stable vibration reduction of the rotary compressor can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a vibration damping device for a rotary compressor showing an embodiment of the present invention, Fig. 2 is a perspective view showing a threaded portion of the vibration damping device, and Fig. 3 is a conventional rotary compressor. FIG. 3 is a sectional view of the vibration damping device of FIG. 2... Sealed case, 14-... Dynamic vibration absorber, 1
5...Inertial body,...Spring, 7-...Screw, 8......Screw.

Claims (1)

[Claims] A coil-shaped connection part whose one end is inserted or fitted into a threaded part provided on the compression element part or into a sealed case in which the electric motor part and the compression element part are fixedly housed, and this connection part. an inertial body having a threaded part whose other end is inserted or fitted along the threaded part, and the threaded end on the connection part side of at least one of these threaded parts is shown in an axial cross section. Vibration damping device for a rotary compressor made with a cutout.