JP3226380B2 - Hermetic compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating hermetic compressor used for a refrigerator or the like.

[0002]

2. Description of the Related Art In recent hermetic compressors, low noise is strongly desired in terms of amenity. Therefore, the need for prevention of noise from the refueling mechanism, which has not been considered a serious problem in the past, is increasing. As a conventional oil supply mechanism, for example, there is a hermetic compressor disclosed in Japanese Utility Model Laid-Open Publication No. 49-48508.

Hereinafter, an example of the above-mentioned conventional hermetic compressor will be described with reference to the drawings.

FIG. 2 is a side sectional view of a conventional hermetic compressor. Reference numeral 1 denotes a hermetic compressor, which is supported in a hermetically sealed container 2 such that a compression section 3 is located above and a motor section 4 is located below. The compression section 3 includes a cylinder 6, a piston 7, a crankshaft 8 having a crank eccentric portion 8a, a connecting rod 9, a bearing 10, and the like provided integrally with the block 5. The motor unit 4 includes a rotor 11,
The rotor 11 is fixed to the crankshaft 8, and the stator 12 is fixed to the block 5.
, The compression unit 3 and the motor unit 4 are integrated to form the electric compression element 13.

An oil passage 14 extends obliquely upward from the center of the lower end of the crankshaft 8 and is opened at the surface of the crankshaft 8 at the bearing 10. Reference numeral 15 denotes a gas vent hole, which is in communication with the oil passage 14 and whose upper end is open to the surface 15a of the crankshaft 5 and whose lower end is inclined so as to remain in the crankshaft, and further passes through the axis of the crankshaft 5. Reference numeral 16 denotes oil stored at the bottom of the closed container 2, and the lower end of the crankshaft 8 is immersed in the oil 16. 1
Reference numeral 7 denotes an oil supply space formed by an oil passage and a gas vent hole whose upper end is closed by a bearing and whose lower end is closed by oil.

The operation of the hermetic compressor constructed as described above will be described below. The refrigerant circulated from the external cooling circuit is once released into the space inside the closed container 2 and is compressed by the compression unit 3 driven by the motor unit 4.
At this time, the oil 16 is sucked upward in the oil passage 14 along the inner wall surface of the oil passage 14 by the centrifugal force generated by the rotation of the crankshaft 8 integrated with the rotor 11, and the bearing 10, Oil can be supplied to the crank eccentric portion 8a, the piston 7 and the like.

In the early stage of starting the motor, the oil 1
Even if the refrigerant melted in 6 evaporates in the oil passage 14, the refrigerant gas is discharged from the crankshaft surface 15 a to the space in the closed casing 2 through the gas vent hole 15, so that the supply of the refrigerant gas is hindered by the refrigerant gas. There is no.

Therefore, the lubrication in the early stage of starting the motor is prevented, and the lubrication is always performed on the sliding parts such as the bearing 10, the crank eccentric part 8a and the piston 7, so that the lubrication failure due to insufficient lubrication and the lubrication of the sliding part are prevented. Can be prevented, and a decrease in efficiency and a decrease in reliability can be prevented.

[0009]

However, in the above-mentioned conventional construction, the oil supply space composed of the oil passage and the gas vent hole whose upper end is closed by the bearing and whose lower end is closed by oil has one closed space and one oil supply space. It has a unique resonance frequency due to the shape of the resonator consisting of the notch and a resonance sound is generated from the refueling space when this resonance frequency substantially matches the integral multiple of the motor rotation frequency There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems, and an object of the present invention is to provide a hermetic compressor that prevents generation of resonance noise from an oil supply space provided in a crankshaft and has extremely low noise.

[0011]

In order to achieve this object, a hermetic compressor according to the present invention is an electric compressor comprising a compression portion such as a piston having an upper piston, a connecting rod, a crankshaft having a crank eccentric portion, and a lower motor portion. A compression element, a sealed container for accommodating the electric compression element, an oil passage extending obliquely upward from the center of the lower end of the crankshaft, and a gas vent hole communicating with the oil passage and having one end opened on the crankshaft surface. In the hermetic compressor, the internal volume of the oil passage is Vm3, the radius of the cross section of the gas vent hole is am, the length is dm, the sound velocity of the gas in the oil passage and the gas vent hole is cm / s, When the rotation frequency of the motor is fHz and an arbitrary integer is n, the resonance frequency f0 shown in (Equation 1) is designed to be (Equation 2).

[0012]

According to the present invention, since the resonance frequency of the refueling space does not match the integral multiple of the rotation frequency of the motor, the refrigerant gas in the refueling space is vibrated by the rotation of the motor to generate resonance sound. And a hermetic compressor with extremely low noise can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hermetic compressor according to the present invention will be described below with reference to the drawings. The same components as those of the related art are denoted by the same reference numerals, and detailed description is omitted.

FIG. 1 shows a first embodiment of a hermetic compressor according to the present invention. In FIG. 1, if the internal volume of the oil passage 14 is V, the radius of the cross section of the gas vent hole 15 is a, and the length is d, V = 2 × 10 −6 m 3 and a = 1.25 × 10 −3.
m and d=5.5.times.10@-3 m. When the sound velocity of the gas in the refueling space 17 is cm / s, the rotation frequency of the motor is fHz, and an arbitrary integer is n, (Equation 3) (by Motoichi Fukuda et al.,
The resonance frequency f0 of the refueling space 17 shown in “Noise countermeasures and noise reduction design” is (Equation 4).

[0015]

(Equation 3)

[0016]

(Equation 4)

The operation of the hermetic compressor constructed as described above will be described below. When the hermetic compressor is mounted and operated in a refrigerator or the like, the sound velocity c in the refueling space 17
According to our experiments, when the refrigerant is HFC-134a, it is about 173 to 177 m / s during steady operation. Therefore, the resonance frequency in the refueling space 17 is f0 =
499-511 Hz. On the other hand, when the power supply frequency is 50 Hz, the operation frequency is usually about 48.5 Hz.

In this case, the resonance frequency f0 of the refueling space 17
Are the 10th and 11th order components, which are 485 Hz and 533., respectively.
5 Hz. When the integral multiple of the operating frequency substantially matches the resonance frequency of the refueling space 17, the refrigerant gas in the refueling space 17 is vibrated to resonate and generate resonance sound.
7 is n times the operating frequency and (n + 1) times (n
Is an arbitrary integer, but in the case of this embodiment, resonance noise is not generated from the refueling space 17 if it is set near the middle of n = 10).

Specifically, it has been clarified by our experiments that resonance noise is not generated from the refueling space 17 within the range of (Equation 4). In the case of the hermetic compressor of this embodiment, the resonance frequency f0 of the refueling space 17 is 499 to 511 Hz.
Is in the range shown by (Equation 4), that is, in the range of 497 to 521 Hz. Therefore, the hermetic compressor of this embodiment does not generate resonance noise from the refueling space 17 during steady operation, and can be a very low noise hermetic compressor.

Also, when the power supply frequency is 60 Hz, 50 Hz
Just think like. When the power supply frequency is 60 Hz, the operation frequency is usually about 58.5 Hz. In this case, the harmonic components of the operating frequency close to the resonance frequency f0 of the refueling space 17 are the eighth-order component and the ninth-order component, and the frequency range represented by (Equation 4) is 482.6 to 511.9 Hz. The resonance frequency f0 in the oil supply space 17 of the hermetic compressor of the present embodiment falls within this range.

Therefore, even when the power supply frequency is 60 Hz, 50
As in the case of Hz, no resonance is generated from the refueling space 17, and a hermetic compressor with extremely low noise can be obtained.

As described above, in the hermetic compressor of the present embodiment, the refueling space 17 is set so that the resonance frequency f0 in the refueling space 17 shown in (Equation 3) falls within the range shown in (Equation 4).
Are designed to prevent the refrigerant gas in the refueling space 17 from being vibrated by the rotation of the motor to generate resonance noise, and to provide a hermetic compressor with extremely low noise.

In this embodiment, one example of the specifications of the refueling space 17 is specifically shown. However, even if these specifications are different from those of the present embodiment, the resonance of the refueling space 17 determined by (Equation 3). If the frequency f0 is within the range shown by (Equation 4), the same effect can be obtained.

The power frequency is 50 Hz or 60 Hz.
If it is dedicated, the specifications of the refueling space 17 corresponding to those dedicated frequencies may be determined, and it is not always necessary to obtain the effect at both 50 Hz and 60 Hz as in the present embodiment.

The sound velocity c of the refrigerant gas in the refueling space 17
Varies depending on the type of the refrigerant, and a similar effect can be obtained by considering the speed of sound corresponding to the refrigerant to be used.

[0026]

As described above, according to the present invention, there is provided an electric compression element comprising a compression part such as a crankshaft having an upper piston, a connecting rod and a crank eccentric part and a lower motor part, and a housing for the electric compression element. A closed container, and an oil passage extending obliquely upward from the center of the lower end of the crankshaft;
In a hermetic compressor comprising a gas vent hole communicating with the oil passage and having one end opened on the crankshaft surface, the internal volume of the oil passage is Vm3, the radius of the cross section of the gas vent hole is am, and the length is am. dm, the sound velocity of the gas in the oil passage and the gas vent hole is cm / s, and the rotation frequency of the motor is fH
z, where n is an arbitrary integer, the resonance frequency f0 shown in (Equation 1) is designed to be (Equation 2), so that the refrigerant gas in the refueling space is rotated by the rotation of the motor. It is possible to prevent a resonance sound from being generated due to the vibration, and to provide a hermetic compressor with extremely low noise.

[0027]

[Brief description of the drawings]

FIG. 1 is a side sectional view of a hermetic compressor showing a first embodiment of the present invention.

FIG. 2 is a side sectional view of a conventional hermetic compressor.

[Explanation of symbols]

 2 Closed container 3 Compression part 4 Motor part 7 Piston 8 Crankshaft 8a Crank eccentric part 9 Connecting rod 13 Electric compression element 14 Oil passage 15 Gas vent hole

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F04B 39/02

Claims (1)

(57) [Claims] 1. An electric compression element comprising a compression part such as a crankshaft having an upper piston, a connecting rod, and a crank eccentric part, and a lower motor part; a hermetic container for accommodating the electric compression element; In a hermetic compressor including an oil passage extending obliquely upward from the lower end center and a gas vent hole communicating with the oil passage and having one end opened on the crankshaft surface, the internal volume of the oil passage is Vm3,
The radius of the cross section of the gas vent hole is am, the length is dm, the sound velocity of the gas in the oil passage and the gas vent hole is cm / s,
When the rotation frequency of the motor is fHz and an arbitrary integer is n, the resonance frequency f0 shown in (Equation 1) becomes (Equation 2). (Equation 1) (Equation 2)