JPS5934876B2 - Refrigeration compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigeration compressor equipped with a discharge muffler that can significantly reduce discharge pressure pulsations.

FIG. 1 shows a conventional two-cylinder hermetic electric compressor with an opposed cylinder arrangement.

In the conventional hermetic electric compressor described above, a compression element 2' and an electric motor 3' are housed inside a hermetically sealed compressor body 1' while being suspended from a spring (not shown). ' and electric motor 3' are connected via a crankshaft 4',
The rotational force generated by the electric motor 3' is transferred to the crankshaft 4.
' to drive the compression element 2'.

The compression element 2' consists of a normal piston rod mechanism, and the rotation of the crankshaft 4' drives the connecting rod 5' and the piston 6' to suck refrigerant gas into the cylinder 7' and compress it. There is.

Regarding the flow of refrigerant gas, the refrigerant gas in the compressor body 1' flows through the tail pipe 9 attached to the morph cover 8'.
', and after the suction noise is reduced by reducing or expanding the refrigerant gas passage in this part, the refrigerant gas passes between the motor rotor 3/-a and the stator 3'-a, or between the motor stator 3'-a and the crankcase. The gas passes between the bells 10', cools them, and reaches an intake gas reservoir 12' provided in the crankcase 11'.

Furthermore, the suction refrigerant scum is sucked from the suction gas reservoir 12' into the cylinder 7' through a suction hole 13' installed in the crankcase 11' via a suction valve (not shown).

On the other hand, the high-temperature, high-strength discharge gas compressed by the screw 6' in the cylinder 7' passes through a discharge valve (not shown).
It is discharged into the cylinder head 14'.

In a multi-cylinder compressor, in order to collect discharge gas discharged from a plurality of cylinders and reduce pressure pulsations, it is recommended to provide a discharge muffler 15' that has both a collection function and a pressure pulsation damping function. There is.

Particularly, when the cylinders 6' are arranged radially around the crankshaft 4', the discharge muffler 15' has a circular shape or a C shape with a part of the circular ring removed along the outer periphery of the compressor main body 16'. When adopting a letter-like shape (in the case of Figure 1)
If the cylinders are arranged in a 90° V shape, the discharge muffler 15' may have an arcuate shape.

The discharge gas discharged into the cylinder head 14' is passed through the connecting pipe 17' to the discharge muffler 15, which has a C-shaped external appearance.
', expands, reduces pressure pulsation, and merges with discharge gas from other cylinder heads, causing discharge muffler 1
Compressor housing 1' with discharge pipe 18' attached to 5'
However, it has the following drawbacks.

(1) Conventional discharge mufflers installed inside the compressor housing often fail to sufficiently reduce discharge pressure pulsations to a predetermined level.

(2) For this reason, an auxiliary discharge muffler was often required outside the compressor housing.

(3) Furthermore, since the pressure pulsation cannot be reduced sufficiently, the pressure drop due to the discharge pipe is large, which leads to a decrease in the refrigerating capacity of the compressor.

(4) Furthermore, in order to escape from the compressor with a large pressure drop due to the discharge pipe, it is necessary to increase the diameter of the discharge pipe. This made it difficult to isolate the vibrations that were transmitted to the compressor housing, making the compressor louder.

The present invention aims to provide a refrigeration compressor equipped with a discharge muffler that can significantly reduce discharge pressure pulsation, and its features include the compressor motor, crankcase, cylinder head, etc. The number of muffler stages is at least two or more, with longitudinal walls adjacent to each other, including the discharge gas collection chamber, so as to match the external shape of the structural member;
Connect the communication pipe through which the discharge gas is introduced between the gathering chamber of each stage and the silencing chamber, or between the silencing chambers, inside the silencing chamber or the gathering chamber, in either the longitudinal direction of the discharge pipe side or the opposite side of the discharge pipe side of those chambers. Depending on the frequency component of the pressure pulsation that you want to reduce, the distance l from the pipe end of the communication pipe to the end wall on the discharge pipe side or the opposite side is set to the length of the frequency component of the pressure pulsation that you want to reduce. This is a refrigeration compressor equipped with a discharge muffler that is bent and stretched a predetermined distance (to be explained in detail later) so that the discharged gas flows in the longitudinal direction of the collecting chamber and the muffling chamber. The pressure pulsation level is reduced by the expansion and contraction of the discharged gas inside the chamber and silencing chamber, and at the same time, the frequency component can be greatly reduced. It is used for all types of refrigeration compressors.

The present invention will be explained with reference to FIGS. 2 to 6.

Fig. 2 is a developed sectional view of the first embodiment of the discharge muffler according to the present invention, Fig. 3 is an explanatory diagram of a cavity-type push-tube type muffler, and Fig. 4 shows the amount of attenuation of pressure waves by the insertion pipe. It is an explanatory diagram.

Figure 2 shows an example of the discharge muffler of the present invention for a two-cylinder horizontally opposed hermetic refrigeration compressor, and the external shape is C-shaped along the compressor motor, crankcase, cylinder head, etc. 19-a is a developed cross-sectional view of a discharge muffler, in which 19-a shows the cylinder head of the first cylinder;
19-b is the cylinder head of the second cylinder, 20-a and 20- are the first and second cylinder heads 19-a, respectively.
.

A connecting pipe connecting 19-b and the discharge muffler 21, 22 a collection chamber for discharged gas, and 23 a communication pipe guiding the discharged gas from the collection chamber 22 to a silencing chamber 24. The longitudinal wall surfaces are adjacent to each other so that the number of muffler stages is two, and 25 is a discharge pipe for sending discharged gas from the muffler chamber 24 to the outside.

In this embodiment, the communication pipe 23 is connected to the discharge pipe 25 within the muffling chamber 24.
Although it is bent and stretched a predetermined distance in the longitudinal direction with respect to the end wall on the side, it may also be bent and stretched a predetermined distance in the longitudinal direction with respect to the end wall on the opposite side to the discharge pipe 25 side.

This point is the same in the embodiments shown in FIGS. 5 and 6.

The distance from the pipe end of the communicating pipe 23 that is open in the muffler 24 to the left end wall of the muffler 24 (the end wall on the opposite side to the discharge pipe 25 side) is l, and the distance in the collecting chamber 22 of the communicating pipe 23 is The center point is represented by a set point p.

The chambers of the discharge muffler 21 are configured into the gathering chamber 22 and the silencing chamber 24 as described above, and the gathering chamber 22 and the silencing chamber 24
The communicating pipe 23 that connects the silencing chamber 24 is bent and stretched longitudinally in the silencing chamber 24 so that the end of the communicating tube 23 is located at an arbitrary position within the silencing chamber 24 (distance l to the left end of the silencing chamber described above). Adjust it to the length of the frequency component of the pressure pulsation you want.

In addition, in a multi-cylinder compressor with a cylinder arrangement in which compression strokes are performed at equal intervals in time as in this case, the position of the gathering point p is between the first cylinder head 19-a and the second cylinder head 19-b. It is desirable that the distances from the point p to the gathering point p be equal.

Description of action.

The discharge gas discharged into the first cylinder head 19-a passes through the connecting pipe 20-a to the collecting chamber 22 of the discharge muffler 21.
The discharge gas discharged into the second cylinder head 19-b passes through the connecting pipe 20-b and enters the collecting chamber 22, expands and reduces the pressure pulsation to some extent. is lowered, and as long as the electric motor continues to rotate, the discharged gas continuously flows into the collecting chamber 22 from each cylinder head 19-a, 19-b.

Inside the gathering chamber 22, the first and second cylinder heads 19
The discharged gases from -a and 19-b flow in one after another,
It expands to reduce these pressure pulsations to some extent and at the same time merge these discharged gases.

Furthermore, the discharged gases that have merged in the gathering chamber 22 flow through the communication pipe 23 in its longitudinal direction and enter the muffling chamber 24, causing expansion and interference of pressure waves.

Here, the distance 1 from the pipe end of the communicating pipe 23 bent and stretched in the muffling chamber 24 to the left end wall of the muffling chamber 24 serves as an insertion part of a known cavity type push-in type muffler.

FIG. 3 is an explanatory diagram of a cavity type push-tube type silencer, and FIG. 4 is an explanatory diagram of the amount of attenuation of pressure waves by the insertion tube.

Here, 26 is an insertion tube, l is a silencer (including correction of the insertion length and the end of the tube), and 27 is a silencer. Figure 4 illustrates this.

Here, k: wavelength constant (k-2πf/c) f: frequency C: Speed of sound It is.

Therefore, the amount of attenuation of the pressure wave due to the distance l from the pipe end to the end wall of the communicating pipe 23 in the silencing chamber 24 in FIG. 2 is -2
It is expressed as 0log l cos kll, and the attenuation is maximum when l cos kll = O.

However, since n""1, 2, 3..., where (λ is the wavelength), from the pipe end of the communicating pipe to the end wall (the end wall on the discharge pipe side or the end wall on the opposite side) It can be seen that the amount of attenuation becomes maximum when the distance l becomes the wavelength of the desired frequency (this point is the same in the embodiments shown in FIGS. 5 and 6).

Therefore, by bending and stretching the communicating pipe 23 in the muffling chamber 24 and adjusting the position of the pipe end of the communicating pipe 23 in the muffling chamber 24, that is, the distance l, to an arbitrary frequency at which pressure pulsation is desired to be attenuated, the frequency component can be reduced. It can be reduced to a large extent.

In particular, in the case of a multi-cylinder compressor with a cylinder arrangement in which compression strokes are performed at equal intervals in time, the position of the gathering point p is set between the first cylinder head 19-a and the second cylinder head 19-a.
9- If the distances from each point to the gathering point p are determined to be equal, the odd-order component of the compressor rotation order component of the pressure pulsation can be eliminated, and the above l is the frequency at which the even-order component is to be eliminated. By matching the components, a large reduction in pressure pulsation can be obtained.

That is, by providing the discharge muffler 21 of the first embodiment, the level of pressure pulsation is reduced by expansion and contraction in the collecting chamber 22 and the muffling chamber 24, and at the same time, any frequency of pressure pulsation can be reduced. Components can be significantly reduced.

(2) Furthermore, by bending and stretching the communicating pipe 23 by a predetermined distance in the longitudinal direction within the muffling chamber, the discharge gas flowing out from the communicating pipe 23 is discharged in the longitudinal direction of the muffling chamber 24, so that the wall of the muffling chamber 24 is The discharge gas flow is therefore less turbulent and the pressure drop caused thereby is reduced.

(3) As mentioned above, the high-pressure discharge gas flows through the discharge pipe 25 and is sent out to the outside of the compressor housing, but at this time, friction on the pipe wall causes a pressure drop, and this pressure drop It is a well-known fact that the pressure drop should be kept as small as possible since it leads to a decrease in the compressor's refrigeration capacity.

The pressure drop in a flow with pressure pulsations is caused by the average flow and pulsating (acceleration, deceleration) flow, and by significantly reducing the pressure pulsation as described above, the pressure drop due to the pulsating flow can be reduced. decreases significantly.

For this reason, the pressure drop in the discharge pipe, which is made sufficiently long to ensure sufficient flexibility to reduce vibration transmission from the compressor body to the compressor housing, is small, and the refrigeration capacity is greatly reduced. No reduction will occur.

(4) Furthermore, the discharge muffler 21 can greatly reduce pressure pulsations and reduce the pressure drop in the discharge pipe 25, which makes the diameter of the discharge pipe 15 thinner and more flexible. be able to.

(5) The pressure pulsation can be sufficiently reduced to a predetermined level with only the discharge muffler inside the compressor casing, and therefore an auxiliary discharge muffler outside the compressor casing is unnecessary.

Note that the number of connecting pipes connecting the cylinder head and the discharge muffler may be one, instead of two as in the above embodiment, or three or more.

However, the gathering room may be a sound-reducing room, and the number of silencers may be two or three or more.

FIG. 5 shows a second embodiment of the present invention, in which the cylinder arrangement is two cylinders in line with two cranks and two cylinders, and there is only one connecting pipe, and the external shape of the muffler is similar to that of a compressor motor or crank. FIG. 2 is a developed cross-sectional view of a discharge muffler having an arcuate shape along structural members such as a case and a cylinder head.

28-a and 28-b are the first and second pistons, 29 is the cylinder head, and 30 is the cylinder head 2.
9 is a discharge cavity, 31 is a connecting pipe for guiding the discharge gas from the discharge cavity 30 to the discharge muffler 32, and 33
34 is a silencer first chamber, 34 is a silencer second chamber, 35 is a bent and stretched communication pipe that guides the discharged gas from the silencer first chamber 33 to the silencer second chamber 34, and 36 is a silencer second chamber. This is a discharge pipe that sends discharged gas from the chamber 34 to the outside.

Here, the center of the communicating pipe of the first muffler chamber 33 is p, the distance from p to the left end wall of the first muffler chamber 33 is l, and the pipe end of the communicating pipe 35 in the second muffler chamber 34 is More silencer 2nd
The distance to the left end wall of the chamber 34 is represented by 12.

In the above-mentioned silencer, the first silencer chamber 33 and the second silencer chamber 34 function as a known cavity type silencer,
Further, the distance l, 12 serves as the insertion length.

Here, by bending and stretching the communication pipe 35 in the silencer second chamber 34, by setting these distances to the lengths of the frequency components whose pressure pulsations are desired to be reduced, those frequency components can be reduced. can be drastically reduced.

FIG. 6 shows a third embodiment of the present invention, and is an example of a discharge muffler for a four-cylinder cruciform cylinder arrangement, in which the external shape of the discharge muffler is similar to that of a compressor motor, crankcase, cylinder head, etc. It is a developed cross-sectional view in the case where a C-shape is formed along the member and the number of muffler stages is three.

37-a, 37-b, 37-c, 37-d
are the respective first, second, third and fourth cylinder heads, 38-
a, 38-b, 3B-c, and 38-d are first, second, third, and fourth connecting pipes 40-a that connect the cylinder heads and the discharge silencer 39, respectively.

40-b is a first gathering chamber, 41-a and 41-b are communication holes that communicate each of the first gathering chambers 40-a and 40-b with the second gathering chamber 42, and 43 is the second gathering chamber. A bent and extended communication pipe is used to communicate the chamber 42 and the muffling chamber 44, and 45 represents a discharge pipe.

The external shape of the silencer is C as described in the above embodiment.
The shape is not limited to a letter shape or an arcuate shape, and other shapes such as an annular shape or a straight shape may be used.

Further, in the above embodiment, the communication pipe 23°35.43 for guiding the discharged gas is provided in the gathering room, the silencing chamber, or between the silencing chambers, and is bent in the silencing chamber, but inside the gathering chamber, the communicating pipe 23° 35. It is also possible to bend it and extend it by a predetermined distance.

Furthermore, although the second and third embodiments differ in structure from the first embodiment, they have similar effects.

In short, as described in each of the above embodiments, the present invention provides a longitudinal wall surface including a collection chamber for discharged gas so that the external shape of the compressor motor, crankcase, cylinder head, etc. conforms to the component. At least two or more muffler stages are installed adjacent to each other, and a communication pipe through which discharged gas is introduced between the gathering chamber of each stage and the muffling chamber or the muffling chamber is installed inside the muffling chamber or the gathering chamber, and the discharge gas from those chambers is connected. Depending on the frequency component in which pressure pulsation is desired to be reduced in the longitudinal direction either on the pipe side or on the side opposite to the discharge pipe side, the distance l from the pipe end of the communicating pipe to the discharge pipe side or the end wall on the opposite side is l-
(1, 3, 5...) x (wavelength of the frequency you want to reduce) by bending and stretching it a predetermined distance, and letting the discharged gas flow in the longitudinal direction of the gathering room and the silencing room. This is a refrigeration compressor equipped with a discharge muffler.

That is, in the present invention, (1) the external shape of the muffler is determined along the compressor motor, the crank case, the cylinder head, and other constituent members, and the longitudinal wall surfaces of the muffler are adjacent to each other to form a multi-stage structure. Therefore, the size of the compressor is
The silencing room does not increase in size as the number of stages in the collective room increases.

([[) Since the number of stages of the muffler is at least two or more, including the collection chamber for the discharge gas from the cylinder head, the discharge gas expands in the collection chamber and the pressure pulsation is reduced to some extent, which further muffles the noise. Upon entering the chamber, expansion and interference of pressure waves occur, and at the same time they are reduced by expansion and contraction, any frequency component of the pressure pulsation can be greatly reduced.

(jiD In particular, in the discharge muffler of the present invention, the end of the communicating pipe for introducing the discharge gas is adjusted in the longitudinal direction of the muffling chamber or the collecting chamber according to the frequency component whose pressure pulsation is to be reduced in the longitudinal direction of the chamber. Bend and stretch by a predetermined distance so that the distance l from the end wall to the discharge pipe side or the opposite side is 1 3 5 ''4'4'4...) x (wavelength of the frequency you want to reduce) By this,
The amount of attenuation of discharge pressure pulsation can be maximized.

In other words, the discharged gas flowing out from the communication pipe is discharged in the longitudinal direction of the muffling chamber (or gathering chamber), so it does not impact directly against the walls of the muffling chamber (or gathering chamber), thereby reducing the flow of the discharged gas. There will be less turbulence and therefore less pressure drop will be caused and the compressor noise can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a partial vertical cross-sectional view of a conventional two-cylinder hermetic electric compressor with opposed cylinder arrangement, Figs. 2 to 6 are drawings related to the present invention, and Fig. 2 is a discharge noise reduction according to the present invention FIG. 3 is an explanatory diagram of a cavity type push-tube silencer; FIG. 4 is an explanatory diagram of the amount of attenuation of pressure waves by the insertion tube; FIGS. 5 and 6 2A and 2B are exploded cross-sectional views of other different embodiments of the present invention, respectively. In the figure, 19-a, 19-b and 29 and 37-a
, 37-b, 37-c, 37-d - cylinder head. 21, 32, 39... Discharge silencer. 22 (gathering room), 24 (silencer room), 33 (silencer first room), 34
(silencer second chamber) and 40-a. 4O-b (first gathering room), 42 (second gathering room), 44 (
Muffling chamber)...The number of stages of the muffler, including the collection chamber for the discharged gas, shall be at least two or more. 23,35°43...Communication pipe. p... Center point in the gathering room (or silencing room) of the communication pipe. l... Distance from the open end of the communication pipe 23 in the silencing chamber 24 to the wall at the left end of the silencing chamber 24. 11...Distance from p to the left end wall of the silencer first chamber 33. 12... Distance from the pipe end of the communication pipe 35 of the second muffler chamber 34 to the left end wall of the second muffler chamber 34. 25, 36, 45...Discharge pipe.

Claims (1)

[Claims] 1. The number of silencer stages is reduced by aligning the longitudinal wall surface of the compressor, including the discharge gas collection chamber, so as to follow the external shape of the morph, crankcase, cylinder head, or other structural members of the compressor. The pipes are also installed in two or more stages, and a communication pipe through which the discharged gas is guided between the gathering chamber and the silencing chamber or the silencing chamber in each tier is installed inside the silencing chamber or the gathering chamber, on the discharge pipe side of those chambers, or on the discharge pipe side of those chambers. Depending on the frequency component in which pressure pulsation is desired to be reduced in either longitudinal direction on the opposite side, the distance l from the pipe end of the communicating pipe to the discharge pipe side or the end wall on the opposite side is a-
(1, 3, 5...) x (wavelength of the frequency you want to reduce) A refrigeration compressor characterized by being equipped with a discharge muffler that allows the flow to flow in the same direction.