JPS5827104Y2 - Hermetic electric compressor - Google Patents

Description

[Detailed description of the invention] This invention is a hermetic electric compressor with a structure in which a discharge side connection pipe connected to a refrigeration cycle and a discharge side muffler of the compressor body are connected by a thin tube in a closed container. The purpose of this is to reduce the vibrations transmitted by the thin tubes, thereby reducing noise.

Household electric refrigerators have thin box bodies, so they tend to generate vibration noise due to the vibrations of the hermetic electric compressor.

Therefore, in order to reduce vibration transmission to the compressor body, the hermetic electric compressor used in household electric refrigerators has a discharge side connection pipe connected to the refrigeration cycle on the discharge side, and a discharge side muffler on the compressor body. The compressor main body is elastically suspended or supported within the closed container by a spring.

On the other hand, household electric refrigerators have become particularly large in recent years, and as a result, the capacity of hermetic electric compressors has also increased.

As a result, the noise of hermetic electric compressors is increasing, and there is an urgent need to reduce this noise. noise generated by the compressor itself or transmitted from the compressor body to the sealed container via the refrigeration oil and vibrated the sealed container, which is generated externally. The vibrations of the compressor body are transmitted through the thin tubes and springs mentioned above, which vibrate the closed container and are generated externally.

Among them, the vibration of the compressor main body is transmitted through the thin tubes mentioned above, and this vibrates the closed container, causing noise to be generated outside.The specific gravity is quite high.

Therefore, the present invention focuses on this point and attempts to reduce noise by attenuating the vibrations of the compressor main body in the thin tube section and reducing the vibrations transmitted to the closed container.

Below, while explaining the problems of the conventional method,
This will be explained using examples.

FIG. 1 is a plan view showing the inside of a hermetic electric compressor.

1 is a cylinder, 2 is a discharge valve chamber, 3 is a discharge side muffler, 4 is a thin tube into which a cylindrical spring 5 is inserted, 6 is a Scotch choke piston 8 is a discharge side connecting tube, 7 is a closed container, and a thin tube 4 connects the discharge side muffler 3 and the discharge side connecting pipe 8 attached to the closed container 7 with silver solder.

Then, due to the reciprocating movement of the piston 6, the refrigerant gas discharged from the cylinder 1 enters the discharge valve chamber 2,
The refrigerant gas flowing through the discharge side muffler 3 passes through the discharge side connecting pipe 8 and reaches the high pressure side of the refrigeration cycle connected to the discharge side connecting pipe 8.

On the other hand, the vibration of the compressor body caused by the compression work is transmitted from the discharge side muffler 3, through the thin tube 4, to the discharge side connecting pipe 8, and the closed container 7 is caused to vibrate by the discharge side connecting pipe 8.

Therefore, if the transmission impedance to the vibration of the capillary tube 4 is small near the natural frequency of the closed container 7 where the discharge side connecting pipe 8 is attached, the vibration of the compressor body will not be damped very much. The container 7 is vibrated and the noise is emitted to the outside.

The natural frequency of the sealed container 7 is generally 1000Hz to 300
It is located around 0Hz and has a very complex distribution, and has many natural frequencies.

Therefore, it is sufficient to increase the transmission impedance to the vibration of the thin tube 4 in this range, that is, to prevent the higher-order natural frequency of the thin tube 4 from falling within this range.

However, as shown in Fig. 1, the thin tube 4 needs to be properly routed through the space inside the closed container 7, so the bending shape becomes complicated and the natural frequency of a higher order than that of the closed container 7 is complicated. ing.

Therefore, in reality, it is impossible to make the natural frequency of the closed container 7 and the natural frequency of the thin tube 4 coincide over this wide frequency band.

Therefore, with the aim of damping the vibrations of the compressor main body in the thin tube section, this invention focuses on a cylindrical spring that is inserted into the thin tube and creates an ideal state in which the specifications of this cylindrical spring are based on reality. By doing so, the vibration damping effect in the thin tube portion can be maximized.

Next, before explaining the specifications of the cylindrical spring 5, which is the basis of the present invention, we will first explain the reason why the vibration of the thin tube can be damped when the cylindrical spring is inserted into the thin tube.

FIG. 2 is a partially enlarged sectional view of section A in FIG. 1.

The thin tube 4 is vibrating in a high-order vibration mode as shown in FIG. 2 due to the vibration of the compressor body.

The cylindrical spring 5 is brought into close contact with the surface of the thin tube 4, and is inserted into the thin tube 4 so as to span the antinode and node of the vibration mode.

Therefore, the amplitude of the vibration of the thin tube 4 is damped by the cylindrical spring 5 as shown in FIG. 2, so that the vibration of the thin tube 4 can be damped.

However, this is an ideal situation, and from a practical standpoint, the thin tube 4 is bent in a complicated manner as shown in FIG. If the cylindrical spring 5 is not inserted into the thin tube 4 after bending, the pressure during the bending process will deform the cylindrical spring 5.
There is a problem that the cylindrical spring 5 cannot be inserted into the cylindrical spring 5.

Therefore, in practice, it is necessary to provide a considerable gap between the thin tube 4 and the cylindrical spring 5, so when the cylindrical spring 5 is inserted into the thin tube 4, it becomes as shown in FIG. The surface of 4 is no longer in close contact with the surface.

Therefore, the damping effect of the cylindrical spring 5 on the thin tube 4 is reduced by half.

At the same time, since the gap between the cylindrical spring and the thin tube is large, the cylindrical spring is prone to cracking due to the vibration of the compressor body.
There is a problem in that rattling noise is likely to occur.

Although it is known that the vibrations of a thin tube can be damped by inserting a cylindrical spring into the thin tube, the reality is that it is difficult to achieve a sufficient effect in practical use as described above.

For this reason, cylindrical springs alone are not sufficient, so countermeasures include increasing the rigidity of the compressor body to reduce high-order vibrations of the compressor body itself, and increasing the rigidity of the closed container.

Therefore, this is a factor that increases the cost of the compressor.

Therefore, the present invention was devised to improve such runner-up points, and will be explained below.

The feature of the cylindrical spring of the present invention is that the initial tension is zero, so that even if the tube is undulating or collapsed, the cylindrical spring remains in close contact with the surface of the tube.
Further, even if the gap between the thin tube and the cylindrical spring is small, the cylindrical spring can be easily inserted into the thin tube.

Hereinafter, the cylindrical spring of the present invention will be explained with reference to FIG.

FIG. 4 is a partially enlarged sectional view corresponding to FIG. 3 in which the cylindrical spring 9 of the present invention is installed.

As mentioned above, the cylindrical spring 9 is manufactured so that the initial tension is zero, so that it is soft and easily adapts to the thin tube 10.

Therefore, as shown in FIG. 4, even if the thin tube 10 is crushed or undulated due to bending of the thin tube 10, the cylindrical spring 9 is brought into close contact with the surface of the thin tube 10 so as to imitate this. This means that the vibrations can be sufficiently damped.

However, what remains in this time order is whether or not the gap between the cylindrical spring 9 and the thin tube 10, which is necessary for mass production when inserting the cylindrical spring 9 into the thin tube 10, can be maintained at a gap that does not generate rattling noise. That's true.

It is complicated to theoretically calculate to what extent this gap, that is, the four dimensions shown in FIG. This is not realistically possible.

For this reason, we have no choice but to find the four dimensions experimentally.

Accordingly, the results of experimentally determining the four dimensions are approximately 0.2 in the straight line portion where the narrow tube 10 has minimal collapse and waviness, and is therefore more likely to generate rattling noise.

For the above reasons, if the four dimensions are set to 0.2 or less, the workability of inserting the conventional cylindrical spring into the thin tube is poor, and the thin tube is crushed, especially in the part where the thin tube is bent, so it is difficult to insert it. It has poor quality and is not suitable for mass production.

On the other hand, the cylindrical spring 9 of the present invention has zero initial tension as described above, so it is very soft and has flexibility even when the thin tube 10 is deformed, and has 4 dimensions or 0.
The cylindrical spring 9 can be easily inserted into the thin tube 10 even if the number of springs is 2 or less.

On the other hand, a cylindrical spring with an initial tension of zero can be easily made by winding the spring at the time of manufacture, so no special effort is required to manufacture the cylindrical spring.

As explained above, the present invention uses a cylindrical spring with an initial tension of zero, which can be easily manufactured, to improve the closeness between the cylindrical spring and the surface of the capillary tube, and furthermore, to reduce the gap between the capillary tube and the cylindrical spring to 0. Since the cylindrical spring can be easily inserted into the thin tube even if it is less than 2, it can be expected to have a large vibration damping effect at low cost without losing mass productivity.

[Brief explanation of drawings]

Figure 1 is a plan view showing the inside of a Scotchoke hermetic electric compressor, Figure 2 is a partially enlarged cross-sectional view corresponding to section A in Figure 1, showing the part where the cylindrical spring is inserted into the thin tube; 3
This figure is a partially enlarged sectional view corresponding to FIG. 2 in a practical state, and FIG. 4 is a partially enlarged sectional view corresponding to FIG. 3 showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Discharge valve chamber, 3... Discharge side muffling chamber, 4... Thin tube, 5... Cylindrical spring, 6... Piston, 7... Sealed container, 8 ...Discharge side connection pipe, 9
... Cylindrical spring, 10... Thin tube.

Claims (1)

[Scope of utility model registration request] In a hermetic electric compressor that has a structure in which the discharge side connecting pipe connected to the refrigeration cycle and the discharge side muffler of the compressor body are connected by a thin tube in a closed container, the initial tension in this thin tube is set to zero. A cylindrical spring manufactured in is inserted,
A hermetic electric compressor characterized in that the gap between the cylindrical spring and the thin tube is 0.2 or less.