JP2000087854A - Closed type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize pressure pulsation in a suction passage and attain increasing of refrigerating capacity and enhancing of efficiency, by using optimum suction passage specification in accordance with a rotational speed of a crankshaft and a kind of a refrigerant, relating to a closed type compressor. SOLUTION: A suction hole 16, muffler 23, and a suction passage 24 connecting a space in the muffler 23 to the suction hole 16, are provided, by constituting a compressor so as to satisfy a formula: 0.87<=L.f/(D.As)<=5.2. Where D(m) is denoted the averaged internal diameter of the suction flow path 24, L(m) is denoted the length of the suction flow path 24, f(Hz) is denoted the rotational speed of a crankshaft, and As(m/sec) is denoted the sound speed of suction gas in the suction flow path 24. Whereby, optimum specification of the suction flow path 24 is provided in accordance with the rotational speed of the crankshaft and a kind of a refrigerant, and refrigerant capacity can be increased and efficiency can be enhanced by optimizing pressure pulsation in the suction flow path 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art There is a strong demand for improved efficiency of hermetic compressors used in refrigerators and the like. Therefore, there has been proposed a method of increasing the refrigerant gas density by increasing the refrigerant gas density by lowering the temperature of the refrigerant gas sucked into the cylinder as much as possible or increasing the pressure as much as possible, thereby increasing the efficiency. ing. For example, in order to lower the temperature of the refrigerant gas as much as possible, a muffler is provided in the suction flow path, and the refrigerant gas returning from the external cooling circuit is sucked almost directly into the muffler without being opened in the closed container. For example, there is a hermetic compressor as disclosed in Japanese Utility Model Laid-Open No. 58-63382.

Hereinafter, an example of the conventional hermetic compressor will be described with reference to the drawings. 8 is a front view of a conventional hermetic compressor, FIG. 9 is a side view taken along line AA of FIG. 8, and FIG. 10 is a cross-sectional view of a main part taken along line AA of FIG.
FIG. 11 is a sectional view of an essential part taken along line BB of FIG.

In FIG. 8, FIG. 9, FIG. 10, and FIG.
Is a closed container, 2 is a mechanical unit, 3 is a motor unit, and the mechanical unit 2 and the motor unit 3 are elastically supported on the closed container 1 by a coil spring 4 integrally. The mechanical unit 2 includes a cylinder 6, a cylinder head 7, a piston 8, a crankshaft 9, a connecting rod 1 provided integrally with the block 5.
0, bearings 11 and the like. The motor unit 3 includes a rotor 1 fixed to a crankshaft 9.
2, the stator 13 is fixed to the block 5 by screws. Reference numeral 14 denotes a lubricating oil which is stored in a lower portion of the closed container 1. Reference numeral 15 denotes a valve plate which has a suction hole 16 and is disposed on an end face of the cylinder 6. The suction hole 16 communicates with the inside of the cylinder 6. A suction valve 17 opens and closes the suction hole 16. 18 is a muffler, 19 is a muffler 18
A muffler inlet flow path that opens into the inside, and 20 is a suction flow path that connects the muffler 18 and the suction hole 17. Reference numeral 21 denotes a suction pipe fixed to the closed container 1, and 22 denotes a suction pipe 2
1 is a close contact coil spring that communicates the muffler inlet flow path 19 with the coil spring 1.

The operation of the hermetic compressor constructed as described above will be described below. The motor unit 3 drives the crankshaft 9, the connecting rod 10, the piston 8, and the like of the mechanical unit 2. The external cooling circuit (not shown) supplies the suction pipe 21, the tight coil spring 22, and the muffler inlet flow path 19.
The refrigerant gas is sucked into the muffler 18 via. This refrigerant gas passes through the suction passage 20 and through the suction hole 16,
It is intermittently sucked into the cylinder 6 according to the opening and closing of the suction valve 17. In this suction stroke, the suction hole 16 is changed according to the change in the volume in the cylinder 6 and the opening and closing of the suction valve 17.
And pressure pulsation occurs in the suction passage 20. The pressure pulsation generated in the suction passage is greatly affected by the pressure wave propagating in the suction passage 20. This pressure wave is generated as an expansion wave when the pressure on the cylinder 6 side in the suction flow path 20 decreases when the suction valve 17 is opened. Next, the expansion wave propagates in the suction flow path 20 toward the space in the muffler 18 at a sonic speed with respect to the flow in the direction opposite to the flow of the refrigerant, and is inverted and reflected in the space in the muffler 18. The compression wave becomes higher in pressure than the surroundings. The compression wave propagates in the suction passage 20 in the same direction as the flow of the refrigerant gas at a sonic speed with respect to the flow, and returns to the cylinder 6. That is, the pressure wave generated as an expansion wave on the cylinder 6 side in the suction flow path 20 reciprocates in the suction flow path 20 and returns to the cylinder 6 as a compression wave. The amount of the refrigerant gas sucked into the cylinder 6 changes depending on the pressure pulsation caused by the behavior of the pressure wave and the opening / closing timing of the suction valve 17.
Refrigeration capacity and efficiency are affected. That is, the refrigerating capacity and efficiency are affected by the specifications of the suction passage 20, the muffler 18, and the suction valve 17.

On the other hand, focusing on the temperature of the refrigerant gas, the refrigerant gas has almost no gap between the close contact coil springs 22.
It is sucked into the muffler 18 while keeping the temperature relatively low, with almost no leakage into the closed container 1. Therefore, the temperature of the refrigerant gas finally sucked into the cylinder 6 is lower than that in the case where the refrigerant gas is once opened in the closed container 1 and then sucked into the muffler 18 without the close contact coil spring 22. And the suction mass of refrigerant gas per unit time (refrigerant circulation amount) increases. As a result, the refrigerating capacity is improved, and the efficiency of the hermetic compressor is improved.

Further, noise generated near the cylinder 6 and the suction hole 16 is attenuated by the space inside the muffler 18,
Noise transmitted from the muffler inlet channel 19 toward the suction pipe 21 is reduced.

[0008]

However, in the above-mentioned conventional configuration, the inner diameter and length of the suction passage 20 which affect the refrigeration capacity and efficiency are not optimal, and therefore the suction passage 20
There is a disadvantage that the effect of pressure pulsation in the inside cannot be sufficiently obtained, and the refrigeration capacity and efficiency may be reduced.
Further, when the hermetic compressor having the same suction flow path 20 specification is operated with different rotation speeds and different refrigerants, the pressure pulsation generated in the suction hole 16 and the suction flow path 20 changes, and the refrigerating capacity and efficiency may be reduced. There was a drawback that there is.

The present invention has been made to solve the conventional problems, and the pressure pulsation in the suction hole and the suction passage is reduced by setting the optimum suction passage specification in accordance with the rotation speed of the crankshaft and the type of the refrigerant. It is an object of the present invention to provide a hermetic compressor having a large refrigeration capacity and high efficiency by being optimized.

Further, in the above-mentioned conventional configuration, when the volume of the muffler 18 is not sufficient, noise and pressure pulsation are transmitted from the muffler 18 to the muffler inlet passage 19 without being sufficiently attenuated, and the noise of the hermetic compressor is reduced. And the pressure pulsation in the suction pipe 21 becomes large, and the pressure pulsation in the suction flow path 20 cannot be sufficiently utilized, so that there is a possibility that refrigeration capacity and efficiency may be reduced.

Another object of the present invention is to reduce the noise and pressure pulsation transmitted from the muffler to the muffler inlet flow path and to sufficiently utilize the pressure pulsation in the suction flow path to increase the refrigeration capacity and efficiency. It is another object of the present invention to provide a hermetic compressor with low noise and pressure pulsation.

Further, in the above-mentioned conventional structure, the pressure pulsation in the suction passage 20 and the opening / closing timing of the suction valve 17 do not coincide with each other, so that the amount of refrigerant gas sucked into the cylinder 6 is reduced and the refrigerating capacity is reduced. Further, there is a disadvantage that the efficiency may be reduced. Further, even when the hermetic compressor is operated at a different rotation speed, the pressure pulsation in the suction flow path 20 and the opening / closing timing of the suction valve 17 are not synchronized, and the refrigeration capacity and efficiency may be reduced. was there.

Another object of the present invention is to optimize the combination of the natural frequency of the suction valve and the specifications of the suction flow passage in accordance with the rotation speed of the crankshaft, so that the pressure pulsation in the suction flow passage and the suction valve Optimize the opening and closing timing of
It is an object of the present invention to provide a hermetic compressor having the highest refrigeration capacity and efficiency.

[0014]

In order to achieve the above object, the present invention provides a motor unit, a mechanical unit such as a crankshaft, a piston, a cylinder, and the like, a closed container containing the motor unit and the mechanical unit, A valve plate having a suction hole and disposed on an end surface of the cylinder, a suction valve for opening and closing the suction hole, a muffler, and a suction flow passage communicating the space in the muffler with the suction hole. The average inner diameter of the suction passage is D (m), the length of the suction passage is L (m), and the rotation speed of the crankshaft is f
(Hz), and the sound velocity of the suction gas in the suction passage is As (m
/ sec), it is configured to satisfy (Equation 3).

[0015]

(Equation 3)

[0016] Thereby, the pressure pulsation in the suction hole and the suction flow path can be optimized, and the refrigerating capacity can be increased and the efficiency can be increased.

Further, in the present invention, the inner volume of the muffler is set to 20 (cm 3) or more. As a result, noise and pressure pulsation transmitted from the muffler to the muffler inlet flow path are reduced, and by sufficiently utilizing the pressure pulsation in the suction flow path, refrigeration capacity and efficiency are high, and noise and pressure pulsation are reduced. be able to.

Further, according to the present invention, the natural frequency of the suction valve is FV (Hz), the rotational speed of the crankshaft is f (Hz),
When the natural numbers are n (1, 2, 3,...), The configuration is such that Expression 4 is satisfied.

[0019]

(Equation 4)

Thus, the combination of the natural frequency of the suction valve and the specifications of the suction passage can be optimized according to the rotation speed of the crankshaft, and the pressure pulsation in the suction passage and the opening / closing timing of the suction valve can be optimized. The refrigeration capacity and efficiency can be maximized.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a motor unit, a mechanical unit such as a crankshaft, a piston and a cylinder, a sealed container accommodating the motor unit and the mechanical unit, A valve plate having a hole and disposed on an end face of the cylinder, a suction valve for opening and closing the suction hole, a muffler, and a suction flow passage communicating the space in the muffler with the suction hole. , The average inner diameter of the suction passage is D (m), and the length of the suction passage is L
(M), and the rotation speed of the crankshaft is f (Hz)
And the sound velocity of the suction gas in the suction flow path is As (m / sec)
, The equation (3) is satisfied, and the timing at which the compression wave returns to the cylinder is:
The average inner diameter of the suction flow passage and the length of the suction flow passage are adjusted so as to be always the same regardless of the number of revolutions of the crankshaft and the type of the refrigerant. If the return timing of the compression wave is too early, the pressure in the suction flow path will decrease after the compression wave returns, and the suction valve will close or the cylinder will be inhaled from the cylinder in the middle of the suction stroke. Since the refrigerant gas flows backward in the flow path, the refrigerating capacity and efficiency are reduced.
On the other hand, if the feedback timing of the compression wave is too late, the compression wave returns at a timing late in the suction stroke, or returns after the suction stroke ends. Therefore, the amount of refrigerant gas sucked into the cylinder decreases, and the pressure in the cylinder during the suction stroke decreases, so that the suction loss increases, and the refrigerating capacity and efficiency decrease. The present invention does not depend on the rotation speed of the crankshaft or the type of refrigerant,
By always optimizing the return timing of the compression wave into the cylinder, there is an effect that the refrigerating capacity is large and the efficiency is high.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the internal volume of the muffler is configured to be 20 (cm3) or more, and the muffler transmits the muffler to the muffler inlet flow path. Noise and pressure pulsation can be reduced, and the pressure wave propagating in the suction passage is reflected at the opening to the muffler so that the attenuation of the pressure wave can be reduced. This has the effect that the pressure pulsation in the road can be sufficiently utilized, and the refrigeration capacity and efficiency can be increased.

According to a third aspect of the present invention, in addition to the configuration of the first aspect, the natural frequency of the suction valve is FV (Hz), the rotational speed of the crankshaft is f (Hz), and the natural number is n (1,
When (2, 3,...) Is satisfied, (Equation 4) is satisfied, and the natural frequency of the suction valve is limited according to the rotation speed of the crankshaft. When the rotation speed of the crankshaft is the same, the suction valve opens and closes n times (n = 1, 2, 3,...) During one rotation of the crankshaft substantially according to its natural frequency. At this time, the longer the total time the suction valve is open, the greater the amount of refrigerant gas drawn into the cylinder.However, if the suction valve is open even during the compression stroke, the refrigerant flows from the cylinder into the suction flow path. Backflow of gas occurs, and the amount of gas sucked into the cylinder decreases. Therefore, if the intake valve opens and closes several times during one rotation of the crankshaft, and the final opening and closing ends too early or too late, the refrigerating capacity and efficiency are reduced, and the optimal closing of the intake valve is meanwhile. There is a timing, or natural frequency. The optimum natural frequency of the suction valve exists for each rotation speed of the crankshaft and is expressed by (Equation 4). In addition, even if the natural frequency of the suction valve is optimal, if the specifications of the suction flow path are not optimal, the compression wave propagating through the suction flow path returns to the cylinder during the compression stroke and pushes up the suction valve. When the refrigerant flows backward from the inside to the suction flow path, or when the opening amount of the suction valve is small, the compression wave returns and the suction gas amount decreases, so that the refrigeration capacity and efficiency cannot be sufficiently increased. Therefore, in addition to the specifications of the suction passage of the first aspect, the pressure pulsation in the suction passage and the opening / closing timing of the suction valve can be optimized by making the specifications of the suction valve satisfy (Equation 4). It has the effect of maximizing refrigeration capacity and efficiency.

[0024]

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.

(Embodiment 1) FIG. 1 is a sectional view showing the vicinity of a muffler and a cylinder of a hermetic compressor according to Embodiment 1 of the present invention. FIG. 2 is a sectional view showing the vicinity of a muffler of the hermetic compressor of the embodiment. FIG. 3 shows a characteristic diagram of the efficiency change with respect to the length of the suction passage of the hermetic compressor of the embodiment.

In FIGS. 1 and 2, reference numeral 23 denotes a muffler, and reference numeral 24 denotes a suction flow path which communicates a space in the muffler 23 with the suction hole 16. The average inner diameter of the suction passage 24 is D
(M), the length of the suction passage 24 is L (m), the rotation speed of the crankshaft 9 is f (Hz), and the sound velocity of the suction gas in the suction passage 24 is As (m / sec). When we do, (Equation 3)
It is configured to satisfy. For example, in the case of the present embodiment, D is 0.008 (m), L is 0.075 (m), the refrigerant uses HFC-134a, and the pressure is 0.115 (MP).
a), the sound velocity As of the refrigerant at a temperature of 50 (° C.) is 169 (m / se)
c), the number of revolutions is 58.5 (Hz), and (Equation 3)
Meets.

The operation of the hermetic compressor constructed as described above will be described below. The pressure wave generated as an expansion wave on the cylinder 6 side in the suction flow path 24 by opening the suction valve 17 in the suction stroke returns to the cylinder 6 as a compression wave by reciprocating in the suction flow path 24. The amount of refrigerant gas sucked into the cylinder 6 changes due to the pressure pulsation caused by the behavior of the pressure wave, so that the refrigerating capacity and efficiency are affected. That is, if the timing at which the compression wave returns to the cylinder 6 is too early, the pressure in the suction flow path will decrease after the compression wave returns, and the suction valve 17 will not operate even during the suction stroke. Since the refrigerant gas is closed or the refrigerant gas flows backward from the inside of the cylinder 6 to the suction passage, the refrigeration capacity and efficiency are reduced. On the other hand, if the feedback timing of the compression wave is too late, the compression wave returns at a timing late in the suction stroke, or returns after the suction stroke ends. Therefore, the amount of the refrigerant gas sucked into the cylinder 6 decreases, and the pressure in the cylinder 6 during the suction stroke decreases, so that the suction loss increases and the refrigeration capacity and efficiency decrease.

Next, the feedback timing of the compression wave and the refrigerating capacity,
The relationship between the efficiencies will be described below by taking the length of the suction channel as an example. If the suction flow path is too short, the return timing of the compression wave will be too early, and if the suction flow path is too long, the return timing of the compression wave will be too late. Therefore, there is an optimal suction flow path length from the viewpoint of pressure pulsation during that time, but there are several points of the suction flow path length where the refrigerating capacity is maximized from our experiments and theoretical calculations. I know. The length of one of the suction passages is relatively long, for example, about 0.3 (m) in the case of the above-described sound velocity, rotation speed, and inner diameter of the suction passage 24. This is a so-called supercharging phenomenon, in which the length of the suction flow path is increased to increase the amplitude of the expansion wave generated in the suction flow path and the amplitude of the compression wave which is the reflected wave, thereby increasing the refrigerating capacity. However, in that case, the expansion wave generated is large, in other words, the pressure drop is large, so that the suction loss increases, and the effect of improving the efficiency is not as great as the effect of improving the refrigeration capacity. On the other hand, the present invention is configured so as to take the maximum value of the refrigeration capacity where the suction flow path is relatively short, and it is possible to greatly improve both the refrigeration capacity and the efficiency. That is, since the suction passage 24 is relatively short, the suction loss is small, and the temperature rise due to the reception of the refrigerant gas in the suction passage 24 is small, and the pressure loss is also small. The efficiency becomes maximum in the length range of the flow path 24.

Also, when the type of refrigerant is different and the sound speed of the refrigerant gas is changed, when the rotational speed of the crankshaft 9 is changed, or when the inner diameter of the suction passage 24 is different, one rotation of the crankshaft 9 is performed. The same effect can be obtained by adjusting the length of the suction passage 24 so that the behavior of the pressure wave inside is approximately the same. For example, when the sound speed of the refrigerant gas increases, the propagation speed of the pressure wave increases, so that the compression wave is returned to the cylinder 6 at the same timing.
Should be lengthened. When the number of rotations of the crankshaft 9 increases, the time per rotation becomes shorter. Therefore, in order to feed back the compression wave at the same timing, the suction passage 24 may be shortened. When the inner diameter of the suction flow path 24 is small, the flow velocity of the refrigerant flowing in the suction flow path 24 increases, and the propagation speed when the pressure wave propagates in the direction opposite to the flow of the refrigerant decreases by the increase in the flow velocity. Therefore, in order to return the compression wave at the same timing, the suction passage 24 may be shortened. Since all of these effects are taken into account (Equation 3), the present invention adjusts the suction flow path 24 to the optimum inner diameter and length even when the type of refrigerant and the rotation speed of the crankshaft 9 are different, so that the present invention is always applied. Since the return timing of the compression wave into the cylinder 6 is optimized, the refrigerating capacity can be increased and the efficiency can be increased.

As described above, the hermetic compressor of this embodiment is
The average inner diameter of the suction passage 24 is defined as D (m),
Is the length of L (m), the rotation speed of the crankshaft 9 is f (Hz), and the sound velocity of the intake gas in the intake passage 24 is As.
(M / sec), it is configured so as to satisfy (Equation 3), so that the optimum suction flow path 24 specification is obtained according to the rotation speed of the crankshaft 9 and the type of refrigerant, and the suction hole 16 In addition, the pressure pulsation in the suction passage 24 can be optimized to increase the refrigerating capacity and the efficiency.

(Embodiment 2) FIG. 4 is a sectional view showing the vicinity of a muffler of a hermetic compressor according to Embodiment 2 of the present invention. FIG. 5 shows a characteristic diagram of the efficiency change with respect to the muffler volume of the hermetic compressor of the embodiment. In FIG. 4, reference numeral 25 denotes a muffler having an inner volume of 20 cm 3 or more. Reference numeral 26 denotes a suction passage which communicates the space inside the muffler 25 with the suction hole 16. The average inner diameter of the suction passage 26 is D (m), the length of the suction passage 26 is L (m), and the crankshaft 9
When the number of rotations is f (Hz) and the sound speed of the suction gas in the suction flow path 26 is As (m / sec), the following equation (1) is satisfied.

The operation of the hermetic compressor configured as described above will be described below. The pressure wave generated as an expansion wave on the cylinder 6 side in the suction flow path 26 by opening the suction valve 17 in the suction stroke returns to the cylinder 6 as a compression wave by reciprocating in the suction flow path 26. By optimizing the pressure pulsation caused by the behavior of the pressure wave, the refrigeration capacity can be increased and the efficiency can be increased. The basic principle is the same as that of the first embodiment, but in the present invention, since the internal volume of the muffler 25 is as large as 20 (cm3) or more, the refrigeration capacity and efficiency can be further increased. The reason will be described below.

The pressure wave generated as the expansion wave is applied to the suction passage 2
6, when the light is reflected by the opening into the muffler 25, if the volume in the muffler 25 is small, the pressure change in the muffler 25 becomes large and the reflection as a completely free end cannot be performed.
The pressure wave (compression wave) after being reflected is attenuated and its amplitude becomes small. Therefore, the larger the volume in the muffler 25 is, the more difficult it is for the pressure wave to be attenuated when reflected. However, when the volume of the muffler 25 exceeds a certain volume, the pressure wave is hardly attenuated. It is a reflection. In a hermetic compressor used for a freezing and refrigeration apparatus, as shown in FIG.
When the volume is about 20 (cm3) or more, the attenuation of the pressure wave is almost eliminated, and the efficiency is maximized.

Further, since the volume of the muffler 25 is as large as 20 (cm 3) or more, the effect of reducing noise and pressure pulsation in the muffler 25 is great, and
9 and noise and pressure pulsation transmitted to the fuel cell 9 can be reduced.

As described above, the hermetic compressor of this embodiment is
The average inner diameter of the suction passage 26 is defined as D (m),
Is the length of L (m), the rotation speed of the crankshaft 9 is f (Hz), and the sound speed of the intake gas in the intake passage 26 is As.
(M / sec), it is configured so as to satisfy (Equation 3), and since the volume of the muffler 25 is configured to be 20 (cm 3) or more, the muffler 25 and the muffler inlet channel 1
9 and the effect of reducing the pressure pulsation can be increased, and the pressure wave propagating in the suction passage 26 can be reduced by the muffler 2.
Since the attenuation of the pressure wave can be reduced when the pressure wave is reflected at the opening to 5, the pressure pulsation in the suction flow path 26 due to the compression wave can be sufficiently utilized, and the refrigeration capacity and efficiency can be increased.

(Embodiment 3) FIG. 6 is a sectional view showing the vicinity of a muffler and a cylinder of a hermetic compressor according to Embodiment 3 of the present invention. FIG. 7 shows a characteristic diagram of the efficiency change with respect to the natural frequency of the suction valve of the hermetic compressor of the embodiment.

In FIG. 6, reference numeral 27 denotes a muffler.
Reference numeral 8 denotes a suction flow path that communicates the space inside the muffler 27 with the suction hole 16. The average inner diameter of the suction passage 28 is D (m), the length of the suction passage 28 is L (m), the rotation speed of the crankshaft 9 is f (Hz), and the suction gas in the suction passage 28 is When the sound speed is As (m / sec), the configuration is such that Expression 3 is satisfied. 29 is a suction valve,
The natural frequency of the suction valve 29 is FV (Hz), the rotational speed of the crankshaft 9 is f (Hz), and the natural number is n (1, 2,.
3,...), (Equation 4) is satisfied.

The operation of the hermetic compressor constructed as described above will be described below. The pressure wave generated as an expansion wave on the cylinder 6 side in the suction flow path 28 by opening the suction valve 29 in the suction stroke returns to the cylinder 6 as a compression wave by reciprocating in the suction flow path 28. By optimizing the pressure pulsation caused by the behavior of the pressure wave, the refrigeration capacity can be increased and the efficiency can be increased.

The basic principle is the same as in the first embodiment,
The present invention further limits the natural frequency of the suction valve 29 according to the rotation speed of the crankshaft 9. When the rotation speed of the crankshaft 9 is the same, the suction valve 29 opens and closes n times (n = 1, 2, 3,...) During one rotation of the crankshaft 9 substantially according to its natural frequency. At this time, as the total time during which the suction valve 29 is open is longer, the amount of refrigerant gas sucked into the cylinder 6 is larger, but when the suction valve 29 is open even during the compression stroke, suction from the cylinder 6 is performed. Backflow of the refrigerant gas occurs in the flow path, and the amount of gas sucked into the cylinder 6 decreases. Therefore, when the intake valve 29 opens and closes several times during one revolution of the crankshaft 9 and the final opening and closing ends too early or too late, the refrigerating capacity and efficiency are reduced, and during that time, the optimal suction is performed. There is a timing at which the valve 29 closes, that is, a natural frequency. The optimum natural frequency of the suction valve 29 exists for each rotation speed of the crankshaft 9 and is represented by (Equation 4). For example, in the case of this embodiment, D is 0.008
(M), L is 0.08 (m), and the refrigerant is HFC-134a.
At a pressure of 0.115 (MPa) and a temperature of 50 (° C.), the sonic velocity As of the refrigerant becomes 169 (m / sec), and the number of revolutions is 5
8.5 (Hz). At this time, the optimum natural frequency of the suction valve 29 is 211 to 281 (H
z), 334 to 404 (Hz),. These natural frequencies are represented by (Equation 4). There are a plurality of optimal ranges of the natural frequency because the number of times the suction valve 29 opens and closes during one rotation of the crankshaft 9 (1, 2, 3,...)
This is because there is an optimum natural frequency for each.

In addition, even if the natural frequency of the suction valve 29 is optimal, if the specifications of the suction passage 28 are not optimal,
When the compression wave propagating in the suction passage 28 returns to the cylinder 6 during the compression stroke and pushes up the suction valve 29, the refrigerant flows backward from the cylinder 6 to the suction passage 28 or the opening amount of the suction valve 29 is small. As a result, the compression wave returns and the amount of suction gas decreases, and the refrigeration capacity and efficiency cannot be sufficiently increased. Therefore, the specifications of the suction passage 28 are
In addition to satisfying Equation (4), by setting the specification of the suction valve 29 so as to satisfy (Equation 4), the suction flow path 2
The pressure pulsation in 8 and the opening / closing timing of the suction valve 29 can be optimized, and the refrigeration capacity and efficiency can be maximized.

As described above, the hermetic compressor of this embodiment is
The average inner diameter of the suction passage 28 is D (m), and the suction passage 28
Is the length of L (m), the rotation speed of the crankshaft 9 is f (Hz), and the sound speed of the intake gas in the intake passage 28 is As.
(M / sec), it is configured so as to satisfy (Equation 3), and the natural frequency of the suction valve 29 is FV (Hz),
The rotation speed of the crankshaft 9 is f (Hz), and the natural number is n
When (1, 2, 3,...), It is configured so as to satisfy (Equation 4), and the natural frequency of the suction valve 29 and the suction flow path in accordance with the rotation speed of the crankshaft 9. 28
The combination of specifications can be optimized, and the pressure pulsation in the suction passage 28 and the opening / closing timing of the suction valve 29 are optimized,
Refrigeration capacity and efficiency can be maximized.

[0042]

As described above, according to the first aspect of the present invention, there are provided a motor unit, a mechanical unit such as a crankshaft, a piston, a cylinder, a closed container accommodating the motor unit and the mechanical unit, A valve plate having a hole and disposed on an end face of the cylinder, a suction valve for opening and closing the suction hole, a muffler, and a suction flow passage communicating the space in the muffler with the suction hole. , The average inner diameter of the suction passage is D (m), and the length of the suction passage is L
(M), and the rotation speed of the crankshaft is f (Hz)
And the sound velocity of the suction gas in the suction flow path is As (m / sec)
In this case, the configuration is such that Equation 3 is satisfied. Therefore, the optimum suction flow path specification is obtained according to the rotation speed of the crankshaft and the type of the refrigerant, and the pressure pulsation in the suction hole and the suction flow path is obtained. Can be optimized to increase the refrigerating capacity and increase the efficiency.

Further, the invention described in claim 2 is the same as the claim 1.
In addition to the invention described in the above, the internal volume of the muffler is 20 (cm3)
With the configuration described above, the effect of reducing noise and pressure pulsation transmitted from the muffler to the muffler inlet passage can be increased, and the pressure wave propagating in the suction passage is reflected at the opening to the muffler. Since the attenuation of the pressure wave can sometimes be reduced, the pressure pulsation in the suction flow channel due to the compression wave can be sufficiently utilized, and the refrigeration capacity and efficiency can be increased.

The invention described in claim 3 is the first invention.
In addition to the invention described in the above, the natural frequency of the suction valve is set to FV
(Hz), the number of revolutions of the crankshaft is f (Hz), and the natural number is n (1, 2, 3,...). Depending on the number, the combination of the natural frequency of the suction valve and the specifications of the suction flow path can be optimized, and the pressure pulsation in the suction flow path and the opening and closing timing of the suction valve are optimized to maximize the refrigeration capacity and efficiency. can do.

[Brief description of the drawings]

FIG. 1 is a sectional view of the vicinity of a muffler and a cylinder according to a first embodiment of a hermetic compressor according to the present invention.

FIG. 2 is a sectional view of the vicinity of a muffler of the hermetic compressor of the embodiment.

FIG. 3 is a characteristic diagram of an efficiency change with respect to a suction flow path length of the hermetic compressor of the embodiment.

FIG. 4 is a sectional view of the vicinity of a muffler and a cylinder according to a second embodiment of the hermetic compressor according to the present invention.

FIG. 5 is a characteristic diagram of an efficiency change with respect to a muffler volume of the hermetic compressor of the embodiment.

FIG. 6 is a sectional view of the vicinity of a muffler and a cylinder according to a third embodiment of the hermetic compressor according to the present invention.

FIG. 7 is a characteristic diagram of an efficiency change with respect to a natural frequency of a suction valve of the hermetic compressor of the embodiment.

FIG. 8 is a front view of a conventional hermetic compressor.

FIG. 9 is a side view of the conventional hermetic compressor of FIG. 8 taken along line AA.

FIG. 10 is a sectional view of a main part of the conventional hermetic compressor of FIG. 8 taken along line AA.

FIG. 11 is a sectional view of a main part of the conventional hermetic compressor of FIG. 9 taken along line BB.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed container 2 Mechanical part 3 Motor part 6 Cylinder 8 Piston 9 Crankshaft 15 Valve plate 16 Suction hole 17 Suction valve 23 Muffler 24 Suction flow path 25 Muffler 26 Suction flow path 27 Muffler 28 Suction flow path 29 Suction valve

Continuation of the front page (72) Inventor Akio Yagi 4-5-2-5 Takaida Hondori, Higashi-Osaka City, Osaka Inside Matsushita Refrigerating Machinery Co., Ltd. (72) Inventor Yo Yo 4-4-2-5 Takaida Hondori, Higashi-Osaka City, Osaka Prefecture No. Matsushita Refrigeration Co., Ltd. (72) Inventor Shuhei Sugimoto 4-2-5 Takaida Motodori, Higashiosaka-shi, Osaka F-term in Matsushita Refrigeration Co., Ltd. 3H003 AA02 AC03 BA05 CC11 CC12 CD02 CD06 CE01

Claims (3)

[Claims] 1. A motor unit, a mechanical unit such as a crankshaft, a piston, a cylinder, and the like, a sealed container accommodating the motor unit and the mechanical unit, and a valve having an intake hole and disposed on an end surface of the cylinder. A plate, a suction valve for opening and closing the suction hole, a muffler, and a suction flow passage communicating the space in the muffler with the suction hole, and an average inner diameter of the suction flow passage is D (m). The length of the suction passage is L (m), the rotation speed of the crankshaft is f (Hz), and the sound velocity of the suction gas in the suction passage is As.
(M / sec), a hermetic compressor configured to satisfy (Equation 1). (Equation 1) 2. The hermetic compressor according to claim 1, wherein the internal volume of the muffler is 20 (cm 3) or more. 3. The natural frequency of the suction valve is FV (Hz),
The rotation speed of the crankshaft is f (Hz), and the natural number is n
The hermetic compressor according to claim 1, wherein (1) is configured to satisfy (Equation 2) when (1, 2, 3, ...). (Equation 2)