JPS58158383A - Enclosed type motor driven compressor - Google Patents

Abstract

PURPOSE:To reduce the noise produced by an accumulator, by selecting the length and the thickness of arcuate plates attached to the inner surface of a cylindrial member constituting the accumulator such that the resonance frequency of vibration produced by the accumulator is changed from the frequency range causing high noises to the frequency range causing low noises. CONSTITUTION:A coolant outlet port formed in an end plate 10 at the bottom of an accumulator 7 is connected to a coolant inlet port 9 of an enclosed container 1 incorporating therein a motor and a compressing mechanism 5 by a bent tube 11 having a straight portion on the inside of the accumulator 7, and one or a plurality of plate 15 having an arcuate inner surface conforming to the inner surface of a cylindrical member 14 are attached to the inner surface of the cylindrical member 14 constituting the accumulator 7 together with the end plate 10. Here, the length and the thickness of the arcuate plates 15 are so selected that the resonance frequency of vibration produced by the accumulator 7 is changed from the frequency range causing high noises to the frequency range causing low noises, whereby it is enabled to reduce the noises produced by the noises produced by the accumulator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a noise damping structure for a hermetic electric compressor equipped with an accumulator.

A conventional electric compressor of this type will be explained with reference to FIG. 2. In FIG. 1, 1 is a cylindrical airtight container, 2 is a stator of an electric motor, 3 is a coil, and 4 is a rotor. 5 is a compression mechanism whose drive shaft 6 is connected to the rotor 4;
The stator 2 is crimped to the cylindrical inner wall of the closed container 10, and the compression mechanism 5 is welded and fixed to the cylindrical inner wall of the closed container 10.

7 is an accumulator arranged in parallel with the closed container 1;
It is supported by the closed container 1 by a support 8. Reference numeral 9 denotes a refrigerant suction port provided horizontally in the closed container 1, and is connected by a bent pipe 11 to a vertical refrigerant outlet provided in the bottom end plate 10 of the accumulator trough. 12 is a discharge pipe for compressed refrigerant.

In the conventional hermetic electric compressor having the above structure, the vibrations of the electric compressor are transmitted to the accumulator trough via the hermetic container 1 and the curved pipe 11, causing the accumulator 7 to resonate and produce abnormal noises in a specific frequency range. occurs. In order to prevent this abnormal noise from occurring, the rigidity of the vibration system is adjusted by changing the material and dimensions of the accumulator 7, or by attaching a damper 13 to the body of the accumulator turf as shown in Figure 1. Although this method has been used to prevent resonance from occurring in a specific frequency range, it has not had sufficient results, and there are various problems in terms of design and cost when implementing it. There is.

The present invention aims to solve this problem by extremely simple means.

In order to achieve this object, the present invention accommodates an electric motor and a compression mechanism integrally coupled with the electric motor inside a closed container, supports an accumulator arranged in parallel with the closed container, and supports the accumulator in the closed container. The refrigerant outlet provided on the end plate at the bottom of the accumulator is connected to the refrigerant suction port of the closed container by a curved pipe having a straight part inside the accumulator, and the cylindrical body constitutes the accumulator together with the end plate of the accumulator. One or more plates having an arcuate cross-section along the cylindrical body inwardly or arcuate plates having bends at both ends are attached.

Hereinafter, a hermetic electric compressor according to an embodiment of the present invention will be described with reference to FIGS. 2 to 5.

In the figure, numerals 1 to 12 indicate the same components as in the conventional example shown in FIG. 1, and detailed explanation will be omitted.

In FIG. 2, 15 is a metal plate with an arc-shaped cross section or an arc-shaped plate with bends at both ends (FIGS. 3 (a) and (b)), which is fixed closely to the inner wall of the accumulator trough. By appropriately setting the length and thickness of the accumulator 7, the resonance frequency of the vibration of the accumulator 7 can be moved from a specific frequency range where the noise is large, and as a result, the noise can be reduced.

Fig. 4 shows an accumulator 7 formed of a steel plate with an outer diameter of 75 mm and a plate thickness of 2 mm, fixed to a closed container l containing an electric compressor with an output of 500 W to 1500 W, as shown in Fig. 2. A closed container l is formed by a bent pipe 11 made of a steel pipe with an outer diameter of about 16 mm and a plate thickness of 1 mm.
In the vibration system connected to the refrigerant suction port 9 of
0, ηm, a plate made of steel material with a length of 50 mm and a thickness of 2 mm and has an arc-shaped cross section or an arc-shaped plate with bends at both ends 1
5 is fixed to the inner wall of the accumulator turf, and vibration is applied in the radial direction at right angles to the axis of the closed container 1 near the refrigerant suction port 9 of the closed container 1. A graph showing the vibration response characteristics of , with the vibration response level (acceleration/force) on the vertical axis.

The horizontal axis shows frequency. In FIG. 4, the solid line shows the characteristics of the vibration system according to the embodiment of the present invention, which includes a plate with an arc-shaped cross section or a plate 15 bent at both ends, and the dotted line shows the conventional vibration system. There is. In this vibration response characteristic, the frequency range of 800 to 1600H2 and 2
For the frequency range of 500-3500H2, use an electric compressor with 5Q
This is a high frequency component of 500 Hz or more of the excitation force generated when operating at a power supply frequency of Hz or 5 QHz, which is a particularly loud frequency range of noise, and is considered to be an important cause of noise generation. In the embodiment of the present invention (solid line), the vibration response level decreases overall in this frequency range, and the part with a high vibration response level, that is, the resonant part, moves to another frequency range. It can be seen that

Figure 5 is a graph showing the noise frequency characteristics of a hermetic electric compressor.The electric compressor according to the embodiment of the present invention (solid line) has a lower sound pressure level at a frequency of around 1600H2 compared to the conventional electric compressor (dotted line). It can be seen that it is decreasing.

As described above, the hermetic electric compressor of the present invention accommodates an electric motor and a compression mechanism integrally connected to the electric motor inside a hermetic container, and an accumulator arranged in parallel with the hermetic container. The refrigerant outlet provided on the end plate at the bottom of the accumulator is connected to the refrigerant suction port of the sealed container by a curved pipe having a straight portion inside the accumulator, and together with the end plate of the accumulator, the accumulator is configured. It is characterized in that one or more plates having an arcuate cross section or arcuate plates having bends at both ends are attached to the inner wall of the cylindrical body. An arcuate plate having a bend in its longitudinal direction is such that when the electric compressor is driven, the resonant frequency of vibration in the accumulator moves from a noisy frequency range to a low noise frequency range.

The transverse dimension and thickness can be set, and therefore a hermetic electric compressor can be produced by a very simple means of appropriately determining the width of a plate having an arc-shaped cross section or a plate having bends at both ends. It has excellent effects such as being able to reduce noise.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a conventional hermetic electric compressor, Fig. 2 is a longitudinal sectional view of a hermetic electric compressor according to an embodiment of the present invention, and Fig. 3 (IL)t (b) is the same. Perspective views of different embodiments of vibration isolation members used in hermetic electric compressors, Figure 4 is a graph showing the vibration response characteristics of the accumulator, and Figure 5 is a graph showing the relationship between frequency and noise of the hermetic electric compressor. It is a graph showing a relationship. 1... Airtight container, 2... Stator, 4...
...Rotor, 5...Compression mechanism, 7...
...Accumulator, 8...Support, 9...
...Suction port, lO... End plate, 11...
...Bent pipe, 14...Cylindrical body, 15...
A plate with an arcuate cross section or an arcuate plate with bends at both ends. Name of agent: Patent attorney Toshio Nakao and 1 other person @
1 Figure 2 Figure 2 (α) (b)

Claims (1)

[Claims] (1) An electric motor and a compression mechanism integrally connected thereto are housed inside a sealed container, an accumulator arranged in parallel with the sealed container is supported by the sealed container, and is provided on an end plate at the bottom of the accumulator. The outlet of the refrigerant is connected to the refrigerant suction port of the sealed container by a curved pipe having a straight part inside the accumulator, and the inner surface of a cylindrical body that constitutes the accumulator together with the end plate of the accumulator has a cross section along the cylindrical body. When an electric compressor drives an arc-shaped plate or an arc-shaped plate with bends at both ends, the resonant frequency of the accumulator's vibration will shift from the noisy frequency range. The hermetic electric compressor according to claim 1, wherein the length and thickness are set to move to a frequency range where noise is small.