JP2002242830A - Reciprocation type compressor having discharge pulsation reduction structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reciprocation type compressor capable of reducing a discharge pulsation without reducing a compression efficiency. SOLUTION: The reciprocation type compressor is provided with a pair of discharge mufflers 133a, 133b provided at a lower part 130 of a cylinder block; a pair of cooling medium flow passages 137, 138 communicating the respective discharge mufflers 133a, 133b with a cooling medium discharge chamber 62 of a cylinder head 60; a pair of muffler covers 134a, 134b sealingly closing a pair of discharge mufflers 133a, 133b; a connection pipe 136 for connecting a pair of muffler covers 134a, 134b each other; and a cooling medium discharge pipe 35 connected to either of a pair of muffler coves 134a, 134b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating compressor having a discharge pulsation reducing structure, and more particularly to a reciprocating compressor having a discharge pulsation reducing structure capable of reducing pulsation generated when refrigerant is discharged.

[0002]

2. Description of the Related Art Generally, a reciprocating compressor is widely used for compressing a refrigerant in a refrigerating apparatus such as a refrigerator.

FIG. 1 is a sectional view of a general reciprocating compressor. As shown in FIG. 1, a general reciprocating compressor includes a case 10 including an upper shell 11 and a lower shell 12, and a component for compressing a refrigerant disposed inside the case 10 at a lower side. And a motor mechanism 20 for driving the compression mechanism.

The electric mechanism 20 includes a stator 21 and a rotor 2 which rotates by electromagnetic interaction with the stator 21.
2 and a crankshaft 23 press-fitted at the center of the rotor 22.

The compression mechanism includes a cylinder block 30 provided on the lower side of the inside of the case 10, a connecting rod 40 eccentrically connected to a lower portion of the crankshaft 23, and a cylinder block connected to the tip of the connecting rod 40. piston 50 which reciprocates in a straight line in the compression chamber 31 formed in the 30
And a cylinder head 60 provided on the front surface 32 (see FIG. 2) side of the cylinder block 30 to seal the compression chamber 31.
It is composed of A refrigerant suction chamber 61 and a refrigerant discharge chamber 62 are vertically defined in the cylinder head 60. A valve assembly 70 is provided between the cylinder head 60 and the front surface 32 of the cylinder block 30. The valve assembly 70 includes a refrigerant suction chamber 61, a refrigerant discharge chamber 62, and a compression chamber 31.
And interrupts the flow of the refrigerant between them.

On the other hand, a suction muffler 80 connected to the refrigerant suction chamber 61 is provided above the cylinder head 60. The suction muffler 80 is connected to a refrigerant suction pipe 81 through which a refrigerant is sucked from a condenser (not shown).

FIG. 2 is an exploded perspective view showing a part of the compression mechanism in the compressor shown in FIG. 1, and FIG. 3 is a bottom view showing a part of the compression mechanism shown in FIG. As shown in FIGS. 2 and 3, a discharge muffler 33 protrudes from the bottom surface of the cylinder block 30, and the discharge muffler 33 is sealed by a muffler cover 34. A refrigerant discharge pipe 35 serving as a flow path for supplying a refrigerant to a condenser (not shown) is connected to the muffler cover 34. A refrigerant discharge hole 32 a is formed in the front surface 32 of the cylinder block 30 and communicates with the discharge muffler 33 through a refrigerant flow path 37.

On the other hand, the valve assembly 70 includes a suction valve 71
a, and a discharge valve plate 72 on which a discharge valve 72a is formed.
The suction valve 71a is connected to the compression chamber 31 and the cylinder head 60.
Interrupts the flow of refrigerant between the refrigerant suction chamber 61 and
The discharge valve 72a is connected to the compression chamber 31 and the cylinder head 60.
The flow of the refrigerant between the refrigerant discharge chamber 62 and the refrigerant discharge chamber 62 is interrupted.

In the above-described configuration, the process of discharging the refrigerant flowing into the compressor after being compressed by the piston 50 is as follows.

First, when the piston 50 retreats in the compression chamber 31 to the bottom dead center side (left side in FIG. 1) with the rotation of the crankshaft 23, the refrigerant suction pipe 8 is moved from the evaporator (not shown).
The refrigerant in a low-temperature and low-pressure state flows into 1. The refrigerant sequentially flows through the suction muffler 80 and the refrigerant suction chamber 61 of the cylinder head 60, and then flows into the compression chamber 31. After that, the crankshaft 23 further rotates and the piston 50
When the refrigerant advances toward the top dead center side (the right side in FIG. 1) inside the refrigerant, the refrigerant is compressed to be in a high temperature and high pressure state. The compressed refrigerant stays in the refrigerant discharge chamber 62 of the cylinder head 60 for a while, and then flows into the discharge muffler 33 through the refrigerant discharge holes 32 a in the front surface 32 of the cylinder block 30 and the refrigerant flow path 37. Then, the high-temperature and high-pressure refrigerant is supplied to the muffler cover 34.
(Not shown) through a refrigerant discharge pipe 36 connected to the
It is exhaled in the direction.

However, in such a reciprocating compressor,
Since the refrigerant is sucked and compressed by the reciprocating motion of the piston 50 in the compression chamber 31 and then discharged, there is a problem that the discharge pulsation occurs because the refrigerant cannot be continuously discharged. Such discharge pulsation of the refrigerant causes noise and vibration of the compressor. In particular, compressor noise generated from a low frequency band around 120 Hz to 500 Hz, which corresponds to the natural frequency of other components of the refrigeration system, has a resonance effect with other components of the refrigeration system, and the noise of the entire refrigeration system is reduced. And increase vibration.

[0012] Such discharge pulsation of the refrigerant can be reduced by increasing the flow resistance of the discharged refrigerant. That is, the cross-sectional area of the refrigerant passage 37 between the refrigerant discharge chamber 62 and the discharge muffler 33 of the cylinder head 60 can be reduced,
By increasing the length of the refrigerant channel 37, the discharge pulsation of the refrigerant is reduced. However, if the cross-sectional area of the refrigerant flow path 37 is too small, the refrigerant does not flow smoothly between the refrigerant discharge chamber 62 and the discharge muffler 33, so that the compression efficiency of the compressor decreases. In addition, since the coolant passage 37 is formed to penetrate the inside of the cylinder block 30, there is a limit in extending the length.

[0013]

SUMMARY OF THE INVENTION The present invention has been devised in order to solve the above-mentioned problems, and it has been proposed to improve the refrigerant discharge structure without lowering the compression efficiency by reducing the compression efficiency. It is an object of the present invention to provide a reciprocating compressor having a discharge pulsation reducing structure capable of reducing pressure.

[0014]

In order to solve the above-mentioned problems, the invention according to the present application provides a pair of discharge mufflers provided at a lower portion of a cylinder block, and a refrigerant discharge of each of the pair of discharge mufflers and a cylinder head. First and second refrigerant flow paths for communicating the chambers, a pair of muffler covers for sealing the pair of discharge mufflers, a connecting pipe for connecting the pair of muffler covers to each other, and a pair of the muffler covers. In a reciprocating compressor including a refrigerant discharge pipe connected to a side communicating with the second refrigerant flow path, the first and second refrigerant flow paths may be cut off at a refrigerant inflow side connected to the refrigerant discharge chamber. The cross-sectional area on the refrigerant outflow side connected to the discharge muffler is formed smaller than the area, and the cross-sectional area on the refrigerant outflow side of the first refrigerant flow path and the cooling area of the second refrigerant flow path are determined based on the displacement. And the cross-sectional area of the outflow side, it is an gist reducing the discharge pulsation of the refrigerant by changing the ratio between the cross-sectional area of the connecting pipe.

Here, when the displacement of the compressor is 3.0 cc, the cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side, the cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side, and the connection Preferably, the inner diameter of the tube is formed in a ratio of about 2: 2: 1.8. Specifically, when the cross-sectional diameter of each of the first and second refrigerant flow paths on the refrigerant inflow side is 6.4 mm, the cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side is 2.0 m.
M, and wherein the cross-sectional diameter of the refrigerant outflow side of the second refrigerant flow path is 2.0 mm, the inner diameter of the connecting pipe is 1.78m
m is desirable.

When the displacement of the compressor is 3.7 to 4.3 cc, the cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side;
The cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side and the inner diameter of the connection pipe are formed in a ratio of about 2: 3.5: 1.8.
Specifically, when the cross-sectional diameter of each of the first and second refrigerant channels on the refrigerant inflow side is 6.4 mm,
The cross-sectional diameter of the refrigerant flow path on the refrigerant outflow side is 2.0 mm, the cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side is 3.5 mm, and the inner diameter of the connection pipe is 1.78. It is desirable.

When the displacement of the compressor is 5.2 to 6.2 cc, the sectional diameter of the first refrigerant flow path on the refrigerant outflow side, the sectional diameter of the second refrigerant flow path on the refrigerant outflow side, and The inner diameter of the connecting pipe is formed in a ratio of about 2: 3.5: 2.2. Specifically, when the cross-sectional diameter of each of the first and second refrigerant flow paths on the refrigerant inflow side is 6.4 mm, the cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side is 2.0 mm. Yes,
The cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side is 3.5.
A mm, the inner diameter of the connecting pipe is preferably a 2.16 mm.

On the other hand, it is preferable that both ends of the connection pipe inserted into the pair of muffler covers are bent at a predetermined angle toward the inner wall of the muffler cover.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the configuration of the reciprocating compressor according to the present invention, since except for some of the compression mechanism portion is substantially identical to the structure of a typical compressor shown in FIG. 1, the same for the same parts thereof And a detailed description thereof will be omitted.

FIG. 4 is an exploded perspective view showing a part of the compressor in the reciprocating compressor according to the present invention. As shown in FIG. 4, the reciprocating compressor according to the present invention includes a cylinder block 130, a cylinder head 60 provided on the front surface 132 side of the cylinder block 130, and a cylinder block 130 and the cylinder head 60. It has a valve assembly 170 interposed therebetween.

On the front side 132 of the cylinder block 130, a refrigerant discharge chamber 62 of the cylinder head 60 (see FIG. 1).
A pair of first and second refrigerant discharge holes 132a communicated with
132b are formed side by side. Cylinder block 13
0 has a pair of first and second discharge mufflers 133 on the bottom surface.
a, 133b (see FIG. 4) are protruded.

First and second discharge mufflers 133a, 13
3b is a hemispherical first and second muffler cover 134
a, 134b are respectively provided, and the first muffler cover 13 is provided.
The 4a and the second muffler cover 134b are communicated by a connecting pipe 136 formed in an arc shape so as to have a predetermined radius of curvature. A refrigerant discharge pipe 135 serving as a flow path for supplying a refrigerant to a condenser (not shown) is connected to the first muffler cover 134a.

FIG. 5 is a partially cutaway view of the compressor of FIG. 4, and FIG. 6 is a sectional view taken along the line II of FIG. As shown in FIG. 5, the first refrigerant discharge hole 132a and the first discharge muffler 1
Reference numeral 33a denotes a second refrigerant discharge hole 1 formed by a first refrigerant flow passage 137 formed through the inside of the cylinder block 130.
32b and the second discharge muffler 133b
8, respectively. First and second refrigerant flow paths 13
7,138 Each refrigerant inlet side 137a, 138a and the refrigerant outflow side 137b, have 138b, the refrigerant outlet side 137b, the cross-sectional area of 138b is a refrigerant inflow side 137a,
138a is formed smaller than the cross-sectional area.

On the other hand, as shown in FIG. 6, first and second muffler covers 134a, 134 are provided at both ends of the connecting pipe 136.
The bent portion 136a is inserted toward the inner wall surface b and bent at a predetermined angle. Therefore, connecting pipe 1
Both ends of the first and second muffler covers 134a, 134a
By the length of the bent portion 136a is inserted into 34b, to prevent these muffler cover 134a, further pulsation 134b occurs.

In the above configuration, the compression chamber 131
The refrigerant compressed in the first and second refrigerants stays in the refrigerant discharge chamber 62 (see FIG. 1) of the cylinder head 60 for a while,
After passing through the refrigerant discharge holes 132a and 132b, the refrigerant inflow sides 137a and 137a of the first and second refrigerant flow paths 137 and 138, respectively.
38a. The discharged pulsation is reduced while the inflowing refrigerant flows through the refrigerant outflow sides 137b and 138b having a small sectional area, and the first and second discharge mufflers 133 are reduced.
a, 133b.

Thereafter, the refrigerant flowing into the second discharge muffler 133b passes through the connecting pipe 136, and flows through the first discharge muffler 133b.
The pulsation is reduced again while flowing in the direction 33a. That is, the flow resistance of the refrigerant in the second discharge muffler 133b due to the movement path extending from the refrigerant in the first discharge muffler 133a is increased, thereby reducing pulsation.

In particular, the first and second refrigerant passages 137, 13
8, the cross-sectional area of the refrigerant outlet side 137b of the first refrigerant channel 137 and the refrigerant of the second refrigerant channel 138 are based on the displacement of the compressor when the cross-sectional area of the refrigerant inlet side 137a and 138a is constant. The cross-sectional area of the outflow side 138b and the connecting pipe 13
By changing the ratio with respect to the sectional area of 6, the discharge pulsation of the refrigerant can be efficiently reduced.

According to the experimental results, the sectional diameter of the first coolant channel 137 and the sectional diameter of the second coolant channel 138, the connecting pipe 1
When the inner diameter of each of the 36 is formed as shown in the following Table 1, the effect of reducing the pulsation of the refrigerant increases without reducing the efficiency of the compressor.

[0029]

[Table 1]

Here, "GRADE" in Table 1 indicates the specifications of the compressor based on the displacement. Specifically, 30 GRADE indicates a compressor having a displacement of 3.0 cc, and
GRADE represents a compressor with a displacement of 3.7 cc, respectively.

As shown in Table 1, when the displacement of the compressor is 3.0 cc, the refrigerant outlet side 1 of the first refrigerant flow path 137
37b, the cross-sectional diameter of the second refrigerant flow path 138 on the refrigerant outflow side 138b, and the inner diameter of the connection pipe 136 are about 2:
It is formed in a ratio of 2: 1.8. That is, the refrigerant inflow side 13 of each of the first and second refrigerant flow paths 137 and 138
7a and 138a, the cross-sectional diameter of the refrigerant outlet side 137b of the first refrigerant flow path 137 is 2.0 mm.
mm, the cross-sectional diameter of the refrigerant outlet side 138b of the second refrigerant flow path 138 is 2.0 mm, and the inner diameter of the connecting pipe 136 is 1.78 mm.
Is formed.

On the other hand, the displacement of the compressor is 3.7 to 4.3c.
In the case of c, the cross-sectional diameter of the refrigerant outlet side 137b of the first refrigerant channel 137 and the refrigerant outlet side 138b of the second refrigerant channel 138
And the inner diameter of the connecting pipe 136 is about 2: 3.5:
It is formed at a ratio of 1.8. That is, the respective refrigerant inflow sides 137 of the first and second refrigerant flow paths 137 and 138
a, 138a has a cross-sectional diameter of 6.4 mm, the cross-sectional diameter of the refrigerant outlet side 137b of the first refrigerant flow path 137 is 2.0 m
m, the cross-sectional diameter of the refrigerant outlet side 138b of the second refrigerant flow path 138 is 3.5 mm, and the inner diameter of the connecting pipe 136 is 1.78. Thus, the displacement of the compressor is 3.7 to 4.3c.
In the case of c, the cross-sectional diameter of the refrigerant outlet side 137b of the first refrigerant flow path 137 and the inner diameter of the connection pipe 136 indicate that the displacement is 3.0 cc
And only the cross-sectional diameter of the refrigerant outlet side 138b of the second refrigerant flow path 138 is larger than the case where the displacement is 3.0 cc.

Further, the displacement of the compressor is 5.2 to 6.2c.
In the case of c, the cross-sectional diameter of the refrigerant outlet side 137b of the first refrigerant channel 137 and the refrigerant outlet side 138b of the second refrigerant channel 138
And the inner diameter of the connecting pipe are formed in a ratio of about 2: 3.5: 2.2. That is, the first and second refrigerant flow paths 1
37, 138, the respective refrigerant inflow sides 137a, 138
a is 6.4 mm, the first refrigerant flow path 137
The refrigerant outlet side 137b has a cross-sectional diameter of 2.0 mm, the refrigerant outlet side 138b of the second refrigerant channel 138 has a cross-sectional diameter of 3.5 mm, and the connecting pipe 136 has an inner diameter of 2.16 mm. As described above, the displacement of the compressor is 5.2 to 6.2.
In the case of cc, the cross-sectional diameter of each of the first and second refrigerant channels 137 and 138 is the same as in the case where the displacement is 3.7 to 4.3 cc, and only the inner diameter of the connection pipe 136 is the displacement 3.0.
cc and 3.7-4.3 cc.

As described above, by increasing the sectional diameter of the refrigerant outlet side 138b of the second refrigerant flow path 138 or the inner diameter of the connection pipe 136 in accordance with the increase in the displacement of the compressor,
The ratio of the refrigerant flowing through the second refrigerant flow path 138 and the connection pipe 136 becomes appropriate, thereby preventing a decrease in compressor efficiency.

FIG. 7 is a graph showing a pulsation waveform at the time of refrigerant discharge in the reciprocating compressor according to the present invention. As shown in FIG. 7, the pulsation waveform of the refrigerant flowing into the first discharge muffler 133a along the first refrigerant flow path 137 (A in FIG. 7).
Sequentially passes through the second refrigerant flow path 138, the second discharge muffler 133 b, and the connecting pipe 136.
The pulsation waveform (B in FIG. 7) of the refrigerant flowing into 3a is about 90
It has a phase difference of ゜. Due to this phase difference, the pulsation waveforms A and B of these refrigerants interfere with each other in the first discharge muffler 133a and are combined into one waveform (C in FIG. 7), and the amplitude and frequency are reduced. Discharged.

FIG. 8 is a graph showing a result of measuring noise when the reciprocating compressor according to the present invention is driven. The first refrigerant flow path 137 and the second refrigerant flow based on the dimensional specifications in Table 1 are shown. The noise of the compressor was measured by forming the passage 138 and the connecting pipe 136, respectively. As shown in the figure, in the conventional compressor, 175 Hz causing resonance with other components of the refrigeration system
Although noise generated from the low frequency band in the vicinity were approximately 23 dB, noise is a compressor according to the present invention generated from the frequency band around 175Hz by pulsation in the refrigerant discharge is reduced about 7dB To a significant extent.

On the other hand, the refrigerant joined by the first discharge muffler 133a is discharged toward a condenser (not shown) through a refrigerant discharge pipe 135 connected to the first muffler cover 134a.

The foregoing has shown and described certain preferred embodiments of the invention. However, the present invention is not limited to the above-described embodiments, and various modifications can be made by anyone having ordinary knowledge in the technical field to which the present invention pertains without departing from the spirit of the present invention. It is.

[0039]

As described above, according to the reciprocating compressor having the discharge pulsation reducing structure according to the present invention, the first and second compressors are provided.
Refrigerant inflow side 137 of each of refrigerant channels 137 and 138
a and 138a, the refrigerant outflow sides 137b and 138
b, the cross-sectional area of the refrigerant outflow side 137b of the first refrigerant flow path 137, the cross-sectional area of the refrigerant outflow side 138b of the second refrigerant flow path 138, and the connecting pipe according to the displacement of the compressor. By changing the ratio to the sectional area of the refrigerant, the discharge pulsation of the refrigerant can be reduced without lowering the efficiency of the compressor. In this way, noise and vibration of the compressor are reduced as the discharge pulsation of the refrigerant is reduced. In particular, according to the present invention, the effect of noise of the entire refrigeration system by the low frequency band noise is reduced can be reduced.

According to the present invention, the first refrigerant flow path 13
7 and the second refrigerant flow path 138, the pulsation waveforms of the refrigerants that merge at the first discharge muffler 133a have a phase difference, so that these two pulsation waveforms interfere with each other, and the refrigerant discharge There is also an effect that pulsation is reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a general reciprocating compressor.

FIG. 2 is an exploded perspective view showing a part of a compression mechanism in the compressor of FIG.

FIG. 3 is a bottom view in which a part of the compression mechanism of FIG. 2 is cut away.

FIG. 4 is an exploded perspective view showing a part of a compression mechanism in the reciprocating compressor according to the present invention.

FIG. 5 is a bottom view in which a part of the compression mechanism of FIG. 4 is cut away.

FIG. 6 is a sectional view taken along line II of FIG. 5;

FIG. 7 is a graph showing a pulsation waveform at the time of refrigerant discharge in the reciprocating compressor according to the present invention.

FIG. 8 is a graph showing a result of measuring noise when the reciprocating compressor according to the present invention is driven.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Case 11 Upper shell 12 Lower shell 20 Electric mechanism part 21 Stator 22 Rotor 23 Crankshaft 30 Cylinder block 31 Compression chamber 32 Front surface of cylinder block 30 32a Refrigerant discharge hole 33 Discharge muffler 34 Muffler cover 35 Refrigerant discharge pipe 36 Discharge pipe 37 refrigerant passage 40 connecting rod 50 piston 60 cylinder head 61 refrigerant suction chamber 62 refrigerant discharge chamber 70 valve assembly 71 suction valve plate 71a suction valve 72 discharge valve plate 72a discharge valve 80 suction muffler 81 refrigerant suction pipe 130 cylinder block 131 compression Chamber 132 Front surface of cylinder block 132a First refrigerant discharge hole 132b Second refrigerant discharge hole 133a First discharge muffler 133b Second discharge muffler 134a First muffler cover 34b Second muffler cover 135 Refrigerant discharge pipe 136 Connecting pipe 136a Bend of connecting pipe 136 137 First refrigerant flow path 137a Refrigerant inflow side of first refrigerant flow path 137 137b Refrigerant outflow side of first refrigerant flow path 137 138th 2 refrigerant flow path 138a Refrigerant inflow side of second refrigerant flow path 138 138b Refrigerant outflow side of second refrigerant flow path 138 170 Valve assembly

Claims (8)

[Claims] 1. A pair of discharge mufflers provided at a lower part of a cylinder block, first and second refrigerant flow paths for communicating each of the pair of discharge mufflers with a refrigerant discharge chamber of a cylinder head. a pair of muffler cover enclosing the muffler respectively, connecting tube and the refrigerant discharge pipe connected to the second refrigerant passage and communicated with the side of the pair of muffler cover interconnecting the pair of muffler cover A reciprocating compressor including:
The second refrigerant flow path has a cross-sectional area on the refrigerant outflow side connected to the discharge muffler smaller than a cross-sectional area on the refrigerant inflow side connected to the refrigerant discharge chamber, and the first refrigerant flow based on the displacement. Reducing the discharge pulsation of the refrigerant by changing the ratio between the cross-sectional area of the refrigerant outlet side of the passage, the cross-sectional area of the refrigerant outlet side of the second refrigerant flow path, and the cross-sectional area of the connection pipe. A reciprocating compressor with a characteristic discharge pulsation reduction structure. 2. The cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side, the cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side, and the inner diameter of the connecting pipe are about 2: 2: 1.8. The reciprocating compressor having the discharge pulsation reducing structure according to claim 1, wherein the compressor is formed at a ratio. 3. The cross-sectional diameter of each of the first and second refrigerant flow paths on the refrigerant inflow side is 6.4 mm, and the cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side is 2.0 mm. The discharge pulsation reducing structure according to claim 2, wherein a cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side is 2.0 mm, and an inner diameter of the connection pipe is 1.78 mm. Reciprocating compressor. 4. The cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side, the cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side, and the inner diameter of the connecting pipe are about 2: 3.5: 1. The reciprocating compressor having the discharge pulsation reducing structure according to claim 1, wherein the compressor is formed at a ratio of 0.8. 5. The cross-sectional diameter of each of the first and second refrigerant flow paths on the refrigerant inflow side is 6.4 mm, and the cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side is 2.0 mm. 5. The discharge pulsation reducing structure according to claim 4, wherein a cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side is 3.5 mm, and an inner diameter of the connection pipe is 1.78 mm. 6. Reciprocating compressor. 6. A cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side, a cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side, and an inner diameter of the connecting pipe are about 2: 3.5: 2. The reciprocating compressor having the discharge pulsation reducing structure according to claim 1, wherein the compressor is formed at a ratio of 2. 7. The cross-sectional diameter of each of the first and second refrigerant flow paths on the refrigerant inflow side is 6.4 mm, and the cross-sectional diameter of the first refrigerant flow path on the refrigerant outflow side is 2.0 mm. The discharge pulsation reducing structure according to claim 6, wherein a cross-sectional diameter of the second refrigerant flow path on the refrigerant outflow side is 3.5 mm, and an inner diameter of the connection pipe is 2.16 mm. Reciprocating compressor. 8. The discharge pulsation reducing structure according to claim 1, wherein both ends of the connection pipe inserted into the pair of muffler covers are bent at a predetermined angle toward an inner wall of the muffler cover. Reciprocating compressor.