JP2017150381A - Muffler and compressor including the muffler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a muffler that can prevent further higher-order resonance in a circumferential direction in a circular acoustic field and a decline in suppressed sound amount due to primary resonance in a radial direction.SOLUTION: In the muffler, an entrance is positioned in the center of an end face on a side of a compressor element of a compressor, relative to an expansion part, an exit is near the center in a height direction and four similar-shape projections positioned in the middle in a radial direction from the center are provided in the radial direction while spaced equally apart from each other in the circumferential direction, where the exit is provided in one or more of the projections.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a silencer attached to a compressor and a compressor equipped with the silencer.

  In a silencer attached to a conventional compressor, the sound pressure inside the silencer when a primary resonance in the circumferential direction of the circular sound field occurs in order to prevent a decrease in volume reduction of the silencer due to resonance occurring at a specific frequency. The position of the antinode in the distribution is the entrance position, and the position of the node is the exit position (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 61-32157

  In the silencer as described in Patent Document 1, it is possible to prevent a decrease in volume reduction of the silencer due to primary resonance in the circumferential direction of the circular sound field. However, when secondary resonance in the circumferential direction occurs, both the outlet position and the inlet position become antinode positions in the sound pressure distribution inside the silencer, and there is a problem that it is not possible to prevent a decrease in the volume reduction of the silencer. . In addition, since the outer periphery of the circular sound field is the exit position, when resonance in the radial direction of the circular sound field occurs, the exit position becomes the antinode position in the sound pressure distribution, preventing a decrease in volume reduction of the silencer. There was also a problem of not.

  The present invention has been made to solve the above-described problems, and prevents a decrease in volume reduction due to higher-order resonance in the circumferential direction and primary resonance in the radial direction in a circular sound field. It aims at providing the silencer which can be performed, and the compressor provided with this silencer.

  The silencer according to the present invention includes a cylindrical expansion portion, and in the silencer attached to the compressor, a protrusion having the same shape protruding toward the center of the expansion portion is arranged in the height direction of the expansion portion. Four in the radial direction of the expansion part are provided near the center and at equal intervals in the circumferential direction, and the fluid inlet is located at the center of the end surface of the compressor on the compressor element side with respect to the expansion part. The fluid outlet is provided at any one or more of the protrusions.

  The silencer according to the present invention includes a cylindrical expansion portion, and in the silencer attached to the compressor, an annular protrusion protruding toward the center of the expansion portion is arranged in the height direction of the expansion portion. Provided uniformly in the circumferential direction in the vicinity of the center, the fluid inlet is located at the center of the end surface of the compressor on the compressor element side with respect to the expansion portion, and the fluid outlet is formed on the projection. It is provided.

  The silencer according to the present invention includes a cylindrical expansion portion, and in the silencer attached to the compressor, the expansion is performed from the position of the node of the sound pressure distribution when primary radial resonance in the in-plane direction occurs. Within the range of ± 5% in the radial direction with respect to the radius of the portion, and in the height direction with respect to the height of the expansion portion from the position of the node of the sound pressure distribution when the primary resonance in the axial direction occurs In the range of ± 3%, four insertion tubes of the same shape are provided in the radial direction of the expansion portion at equal intervals in the circumferential direction, and a fluid inlet is provided to the expansion portion with respect to the compressor of the compressor. It is located at the center of the end surface on the element side, and the outlet of the fluid is any one or more of the insertion tubes.

  The silencer according to the present invention includes a cylindrical expansion portion, and in the silencer attached to the compressor, the expansion is performed from the position of the node of the sound pressure distribution when primary radial resonance in the in-plane direction occurs. Within the range of ± 5% in the radial direction with respect to the radius of the portion, and in the height direction with respect to the height of the expansion portion from the position of the node of the sound pressure distribution when the primary resonance in the axial direction occurs In the range of ± 3%, four indentations of the same shape are provided on the outer peripheral surface of the expansion portion at equal intervals in the circumferential direction, and a fluid inlet is provided to the compressor element of the compressor. It is located in the center of the end face on the side, and the outlet of the fluid is any one or more of the recesses.

  The silencer according to the present invention includes a cylindrical expansion portion, and in the silencer attached to the compressor, the expansion is performed from the position of the node of the sound pressure distribution when primary radial resonance in the in-plane direction occurs. Within the range of ± 5% in the radial direction with respect to the radius of the portion, and in the height direction with respect to the height of the expansion portion from the position of the node of the sound pressure distribution when the primary resonance in the axial direction occurs In the range of ± 3%, four planes of the same shape are provided on the outer peripheral surface of the expansion portion at equal intervals in the circumferential direction, and a fluid inlet is provided in the compressor element of the compressor with respect to the expansion portion. It is located in the center of the end face on the side, and the outlet of the fluid is set to any one or more central positions in the plane.

  The silencer according to the present invention includes a cylindrical expansion portion, and in the silencer attached to the compressor, the expansion is performed from the position of the node of the sound pressure distribution when primary radial resonance in the in-plane direction occurs. Within the range of ± 5% in the radial direction with respect to the radius of the portion, and in the height direction with respect to the height of the expansion portion from the position of the node of the sound pressure distribution when the primary resonance in the axial direction occurs An annular recess is uniformly provided in the circumferential direction of the expansion portion within a range of ± 3%, and a fluid inlet is provided at the center of the end surface on the compressor element side of the compressor with respect to the expansion portion. And at least one fluid outlet is provided at a central position in the height direction of the recess.

  The compressor which concerns on this invention fixes said silencer to the said fixed scroll so that the discharge hole of the fixed scroll which comprises the compressor element may come to the center position of the said silencer.

  According to the silencer according to the present invention, by specifying the fluid inlet position and the fluid outlet position, the silencer does not decrease even at a frequency where the volume reduction is reduced in the conventional silencer. Has an effect.

  According to the compressor according to the present invention, since the above silencer is mounted, the volume reduction is not reduced even at a frequency where the volume reduction is reduced in the conventional silencer, and noise can be reduced.

It is a schematic block diagram which shows the mechanism of the scroll compressor provided with the silencer which concerns on Embodiment 1 of this invention. It is a perspective view which shows the example of a shape of the silencer which concerns on Embodiment 1 of this invention. It is a top view and a sectional view of a silencer concerning Embodiment 1 of the present invention. It is a perspective view which shows the example of a shape of the silencer of the shape which becomes the most basic. It is a top view and a sectional view of a silencer having the most basic shape. It is the schematic which expands and shows the part of the silencer of the scroll compressor to which the silencer of the most basic shape was attached. It is a sketch which shows the model example of the interior space of the silencer of the shape which becomes the most basic. It is the top view and side view which show the model example of the interior space of the silencer of the shape which becomes the most basic. It is the graph which showed the characteristic of the volume reduction with respect to the frequency about a basic shape. It is the top view and elevation sectional drawing of sound pressure distribution of the interior space of the silencer of a basic shape when resonance arises. It is the top view and elevation sectional drawing of sound pressure distribution of the interior space of the silencer of a basic shape when resonance arises. It is the top view and elevation sectional drawing of sound pressure distribution of the interior space of the silencer of a basic shape when resonance arises. It is the top view and elevation sectional drawing of sound pressure distribution of the interior space of the silencer of a basic shape when resonance arises. It is the top view and elevation sectional drawing of sound pressure distribution of the interior space of the silencer of a basic shape when resonance arises. It is the top view and elevation sectional drawing of sound pressure distribution of the interior space of the silencer of a basic shape when resonance arises. It is the top view and elevation sectional drawing of sound pressure distribution of the interior space of the silencer of a basic shape when resonance arises. The correspondence table of coefficient βnm / π in a low order is shown. 5 is a graph showing the relationship between ΔNR and x / a. It is the graph which showed the characteristic of the volume reduction with respect to the frequency which set the exit side observation point in the position of a node. 3 is a graph showing the relationship between ΔNR and z / L ′. It is the graph which showed the characteristic of the volume reduction with respect to the frequency which set the exit side observation point in the position of a node. It is the graph which showed the characteristic of the volume reduction with respect to the frequency which set the exit side observation point in the position of a node. It is a sketch which shows the interior space of the silencer which concerns on Embodiment 1 of this invention. It is the top view and side view which show the model example of the internal space of the silencer which concerns on Embodiment 1 of this invention. The characteristics of the volume reduction with respect to the frequency when the coordinates of the observation point on the entrance side are (x, y, z) = (0, 0, −35) and the coordinates of the observation point on the exit side are (0, 70, 35) are shown. It is a graph. 5 is a matrix showing the number of obstacles in a circular sound field, the positions of the nodes of the sound pressure distribution when primary resonance occurs in the circumferential direction, and the positions of the nodes of the sound pressure distribution when secondary resonance occurs. It is a sketch which shows the internal space of the silencer which concerns on Embodiment 2 of this invention. It is the top view and side view which show the model example of the internal space of the silencer which concerns on Embodiment 2 of this invention. Characteristics of volume reduction with respect to frequency when the coordinates of the observation point on the entrance side are (x, y, z) = (0, 0, −35) and the coordinates of the observation point on the exit side are (0, 72.5, 35). It is the graph which showed. It is a sketch which shows the model example of the interior space of the silencer of the shape which becomes the most basic. It is the top view and side view which show the model example of the interior space of the silencer of the shape which becomes the most basic. It is the graph which showed the characteristic of the volume reduction with respect to the frequency of the exit side observation point with respect to the entrance side observation point. It is the graph which showed the characteristic of the volume reduction with respect to the frequency of the exit side observation point with respect to the entrance side observation point. It is the graph which showed the characteristic of the volume reduction with respect to the frequency of the exit side observation point with respect to the entrance side observation point. It is the graph which showed the characteristic of the volume reduction with respect to the frequency of the exit side observation point with respect to the entrance side observation point. It is the graph which showed the characteristic of the volume reduction with respect to the frequency of the exit side observation point with respect to the entrance side observation point. It is the graph which showed the characteristic of the volume reduction with respect to the frequency of the exit side observation point with respect to the entrance side observation point. It is the top view and side view which show the model example of the internal space of the silencer of a basic shape. It is a matrix of R _w1 with respect to _w1 . The result of the table | surface of FIG. 39 is converted into a graph. It is explanatory drawing for demonstrating an example of the design method of a hollow. It is a sketch which shows the internal space of the silencer which concerns on Embodiment 3 of this invention. It is the top view and side view which show the model example of the internal space of the silencer which concerns on Embodiment 3 of this invention. The characteristics of the volume reduction with respect to the frequency when the coordinates of the observation point on the entrance side are (x, y, z) = (0, 0, −35) and the coordinates of the observation point on the exit side are (0, 75, 35) are shown. It is a graph. It is the top view and elevation which show the sound pressure distribution of the interior space of the silencer which concerns on Embodiment 3 of this invention when resonance arises. It is a sketch which shows the internal space of the silencer which concerns on Embodiment 3 of this invention. It is a sketch which shows the internal space of the silencer which concerns on Embodiment 4 of this invention. It is the top view and side view which show the model example of the internal space of the silencer which concerns on Embodiment 4 of this invention. The characteristics of the volume reduction with respect to the frequency when the coordinates of the observation point on the entrance side are (x, y, z) = (0, 0, −35) and the coordinates of the observation point on the exit side are (0, 75, 35) are shown. It is a graph. It is the top view and elevation which show the sound pressure distribution of the interior space of the silencer which concerns on Embodiment 4 of this invention when resonance arises. It is explanatory drawing for demonstrating an example of the design method of a plane. It is a sketch which shows the internal space of the silencer which concerns on Embodiment 5 of this invention. It is the top view and side view which show the model example of the internal space of the silencer which concerns on Embodiment 5 of this invention. The characteristics of the volume reduction with respect to the frequency when the coordinates of the observation point on the entrance side are (x, y, z) = (0, 0, −35) and the coordinates of the observation point on the exit side are (0, 75, 35) are shown. It is a graph. It is the top view and side view which show the model example of the internal space of the silencer which concerns on Embodiment 5 of this invention. It is a matrix of R _w2 with respect to _w2 . The result of the table | surface of FIG. 56 is converted into a graph. It is explanatory drawing for demonstrating an example of the design method of a hollow. It is a sketch which shows the internal space of the silencer which concerns on Embodiment 6 of this invention. It is the top view and side view which show the model example of the internal space of the silencer which concerns on Embodiment 6 of this invention. The characteristics of the volume reduction with respect to the frequency when the coordinates of the observation point on the entrance side are (x, y, z) = (0, 0, −35) and the coordinates of the observation point on the exit side are (0, 65, 35) are shown. It is a graph. It is a sketch which shows the internal space of the silencer which concerns on Embodiment 5 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one. Further, in the following drawings including FIG. 1, the same reference numerals denote the same or equivalent parts, and this is common throughout the entire specification. Furthermore, the forms of the constituent elements shown in the entire specification are merely examples, and are not limited to these descriptions.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram showing a mechanism of a scroll compressor 100 including a silencer 14 according to Embodiment 1 of the present invention. The mechanism of the scroll compressor 100 will be described based on FIG.

  The scroll compressor 100 includes a sealed container 1, an electric motor element 4, and a compressor element 6. The sealed container 1 constitutes an outline of the scroll compressor 100. The electric motor element 4 is composed of a stator 2 and a rotor 3 provided inside the sealed container 1, and drives the compressor element 6. The compressor element 6 is disposed inside the sealed container 1 and is driven by the electric motor element 4 via the crankshaft 5.

  The compressor element 6 includes a frame 7, a fixed scroll 8, and an orbiting scroll 10. The frame 7 is fixed inside the sealed container 1 and supports the fixed scroll 8 and the swing scroll 10. Further, the frame 7 forms a pair with the bearing 11 and also serves as a support for the crankshaft 5. The fixed scroll 8 is fixed to the frame 7 and compresses a fluid (for example, a refrigerant or a heat medium) together with the swing scroll 10. The orbiting scroll 10 is accommodated in a space 9 formed by the frame 7 and the fixed scroll 8, and the rotational force of the electric motor element 4 is transmitted via the crankshaft 5.

Further, the fixed scroll 8 is formed with a discharge hole 12 for discharging the compressed and high pressure fluid. The discharge hole 12 is provided with a discharge valve 13 that opens and closes the discharge hole 12. Further, a silencer 14 is disposed on the downstream side of the discharge hole 12 in the fixed scroll 8. One or a plurality of blowing holes 15 are provided on the side surface of the silencer 14.
A space 16 surrounded by the silencer 14 and the fixed scroll 8 is formed on the downstream side of the discharge valve 13. In addition, a space 17 surrounded by the sealed container 1, the fixed scroll 8, and the silencer 14 is formed on the downstream side of the silencer 14.

About the scroll compressor 100 comprised as mentioned above, the effect | action is demonstrated below.
When power is supplied to the stator 2, the rotor 3 rotates by receiving the rotational force from the rotating magnetic field generated by the stator 2. The crankshaft 5 is rotationally driven by the rotation of the rotor 3. When the crankshaft 5 is rotationally driven, a driving force is transmitted to the swing scroll 10. The rocking scroll 10 is swung by an Oldham mechanism (not shown) and is swung.

  When the orbiting scroll 10 performs an orbiting motion, the fixed scroll 8 and the orbiting scroll 10 compress the fluid in the space 9. The compressed fluid is blown out from the discharge holes 12 of the fixed scroll 8. The discharged fluid pushes up the discharge valve 13 and is discharged into the space 16. Here, the fluid discharged into the space 16 passes through the blowing hole 15 and is guided to the space 17.

  The silencer 14 is installed for the purpose of reducing the noise generated by the fluid blown out from the discharge hole 12 while the fluid is blown out from the blowout hole 15. Such a silencer 14 is generally called an expansion silencer.

  FIG. 2 is a perspective view showing a shape example of the silencer 14. FIG. 3 is a plan view and a cross-sectional view of the silencer 14. Fig.3 (a) is a top view which shows the structural example of the silencer 14, FIG.3 (b) is AOA sectional drawing of (a). The silencer 14 will be described with reference to FIGS. In the following, the size, material, fixing method, etc. of the members will be described with specific examples. However, they can be changed, and the invention is not limited to only the examples.

  The material of the silencer 14 is an iron-based plate material having a plate thickness of 3 mm, for example. The silencer 14 includes a cylindrical portion 18, four insertion tubes 19, a circular top plate 20, and an annular flat plate 21, and various components are joined together by welding. The insertion tube 19 corresponds to the “projection” of the present invention.

The cylindrical portion 18 has a height of, for example, 70 mm and an outer diameter of, for example, 206 mm. Further, four holes 22 having a diameter of, for example, 20 mm are provided at equal intervals in the circumferential direction at a position of, for example, 35 mm in the height direction of the cylindrical portion 18. The insertion tube 19 is welded to each hole 22 so as to be inside the cylindrical portion 18 in the radial direction.
The insertion tube 19 has an inner diameter of 20 mm, for example, and extends from the central shaft 23 of the cylindrical portion 18 to a position of 70 mm, for example.

A circular top plate 20 is welded to one end of the cylindrical portion 18, and an annular flat plate 21 is welded to the opposite end.
The diameter of the top plate 20 is, for example, 206 mm.
The flat plate 21 has an inner diameter of, for example, 206 mm and an outer diameter of, for example, 280 mm. On the concentric circle having a diameter of, for example, 250 mm with respect to the flat plate 21, six bolt holes 24 are provided at equal intervals in the circumferential direction in order to fix the silencer 14 to the fixed scroll 8 with bolts.
The silencer 14 is fixed so that the discharge hole 12 of the fixed scroll 8 is at the center position of the silencer 14.

Here, the operation principle of the silencer will be described based on the silencer having the most basic shape.
FIG. 4 is a perspective view showing an example of the shape of the silencer 25 having the most basic shape. FIG. 5 is a plan view and a cross-sectional view of the silencer 25 having the most basic shape. Fig.5 (a) is a top view which shows the structural example of the silencer 25, FIG.5 (b) is AA-A sectional drawing of (a). The silencer 25 will be described with reference to FIGS. 4 and 5.

  The material of the silencer 25 is an iron-based plate material having a plate thickness of 3 mm, for example. The silencer 25 includes a cylindrical portion 26, a circular top plate 28A having a blowout hole 27 in the center, and an annular flat plate 28B, and various components are joined together by welding.

The cylindrical portion 26 has a height of, for example, 70 mm and an outer diameter of, for example, 206 mm.
A circular top plate 28A is welded to one end of the cylindrical portion 26, and an annular flat plate 28B is welded to the opposite end.
The top plate 28A has a diameter of, for example, 206 mm, and a blowout hole 27 having a diameter of, for example, 20 mm is formed at the center of the circle.
The flat plate 28B has an inner diameter of, for example, 206 mm and an outer diameter of, for example, 280 mm. On the concentric circle having a diameter of, for example, 250 mm with respect to the flat plate 21, six bolt holes 30 are provided at equal intervals in the circumferential direction in order to fix the silencer 25 to the fixed scroll 8 with bolts.
The silencer 25 is fixed so that the discharge hole 12 of the fixed scroll 8 is at the center position of the silencer 25.

Hereinafter, the muffler evaluation method will be described using the muffler 25 as an example.
FIG. 6 is an enlarged schematic view showing a portion of the silencer 25 of the scroll compressor to which the silencer 25 is attached. The shape of the silencer 25 is such that both the discharge hole 12 of the fixed scroll 8 and the blowout hole 27 of the silencer 25 are located at the center of the circular end of the cylindrical space 31 surrounded by the fixed scroll 8 and the silencer 25. It is like that. Here, the central position on the pipeline entrance side of the discharge hole 12 of the fixed scroll 8 is defined as the entrance side observation point 32, and the central position on the pipeline entrance side of the blowout hole 27 of the silencer 25 is defined as the exit side observation point 33. The sound pressure at the inlet side observation point 32 p1, the sound pressure level _{L p1,} the sound pressure at the outlet side observation point 33 p2, and the sound pressure level _{L p2,} defined by the following equation a reduced volume NR (1) .

この式（１）は、白木万博著「騒音防止設計とシミュレーション」（産業科学システムズ）、１９８７年に記載されている。

This equation (1) is described in “Noise prevention design and simulation” written by Masahiro Shiraki (Industrial Science Systems), 1987.

A positive value of the sound reduction NR indicates that the sound pressure level (L _p2 ) at the exit side observation point 33 is smaller than the sound pressure level (L _p1 ) at the entrance side observation point 32. It shows that the noise is suppressed by the silencer 25. That is, the larger the value of the sound reduction NR, the greater the effect of sound reduction by the silencer 25.

  In order to simplify the problem, the acoustic mode inside the target cylindrical space 31 does not change at the closed end or the open end for the fluid flow path from the inlet side observation point 32 to the outlet side observation point 33. The inlet-side observation point 32 and the outlet-side observation point 33 were capped to form a closed end, and the discharge valve 13 was removed. FIGS. 7 and 8 show models of a typical silencer internal space 34 in which various dimensions are integers. FIG. 7 is a sketch diagram illustrating a model example of the internal space 34 of the silencer 25. FIG. 8 is a plan view and a side view showing a model example of the internal space 34 of the silencer 25.

This shape shown in FIGS. 7 and 8 is called a basic shape. The coordinates of the origin 35 are (x, y, z) = (0, 0, 0). The unit in this coordinate system is mm. The coordinates of the entrance-side observation point (pt. 1) 36 are (0, 0, −35), and the coordinates of the exit-side observation point (pt. 2) 37 are (0, 0, 70). The entrance end face 38 is an acoustic radiation surface, and a uniform particle velocity of 1 m / s is given regardless of the frequency. The fluid is dry air, the speed of sound is c = 340 m / s, and the air density is r = 1.225 kg / m ³ .

  With respect to the basic shape, acoustic analysis was performed in 5 Hz increments between 5 Hz and 5000 Hz with the inner space 34 of the silencer filled with finite elements and the inlet side end surface 38 as the input surface. FIG. 9 is a graph showing the characteristics of volume reduction with respect to frequency for the basic shape. The horizontal axis in FIG. 9 indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB.

  As shown in FIG. 9, there are a plurality of dip that is a pointed valley and a peak that is a pointed peak on the characteristic of the volume reduction with respect to the frequency. Among these, the circled peaks and dips are dip (1) 39, peak 40, dip (2) 41, dip (3) 42, dip (4) 43, dip (5) 44, dip in order from the lowest frequency. (6) 45 and dip (7) 46.

The causes of the peaks and dip are shown below.
The dip (1) 39 is a dip generated by the inner space 34 of the silencer acting as a resonator type silencer. The frequency f of the dip (1) 39 is obtained by the following Helmholtz resonance equation (2) using the sound velocity c, the length L and the cross-sectional area S of the inlet side pipe 47, and the volume V of the inflating portion 48. Can do.

  At frequencies below this frequency f and frequencies near this frequency f, the volume reduction is 0 or less, and the exit side observation point (pt. 2) 37 is higher than the sound pressure level at the entrance side observation point (pt. 1) 36. Since the sound pressure level at is higher, the frequency of the dip (1) 39 is preferably lower. At a frequency lower than the frequency generated by the dip (1) 39, the volume reduction is always 0 or less, so the frequency of the dip (1) 39 is set to the lower limit frequency fmin of the silencer of the basic shape. Focusing on the volume V of the inflating portion 48, the lower limit frequency fmin moves to a lower frequency as the volume V of the inflating portion 48 is larger, and moves to a higher frequency as the volume V of the inflating portion 48 is smaller.

  FIG. 10 is a plan view and an elevational sectional view of the sound pressure distribution in the internal space of the silencer having the basic shape when resonance occurs. That is, FIG. 10 shows a plan view of the sound pressure distribution in the internal space 34 of the silencer having the basic shape at a frequency at which the peak 40 occurs, and a sectional view cut along the yz plane. In FIG. 10, the position of the node 49 in the sound pressure distribution is indicated by a double line. As shown in FIG. 10, the node 49 of the sound pressure distribution overlaps with the exit-side observation point (pt. 2) 37.

  Since the sound pressure level at the node position is low and lower than the sound pressure level at the entrance-side observation point (pt. 1) 36, the sound volume is increased and the peak 40 is generated as a result. The node 49 of the sound pressure distribution is formed in a hemispherical shape at a position separated from the origin 35 by the length L ′ of the expansion portion 48 with the origin 35 as the antinode of the sound pressure distribution. That is, the peak 40 occurs when the quarter wavelength is just within the length L ′. Therefore, the frequency f at which the peak 40 occurs can be obtained by the following equation (3).

  Dip (2) 41, dip (3) 42, dip (4) 43, dip (5) 44, dip (6) 45, dip (7) 46 are all in the expansion portion 48 of the inner space 34 of the silencer. Resonance occurs, the exit-side observation point (pt. 2) 37 becomes an antinode in the sound pressure distribution in the inner space 34 of the silencer, and the sound pressure level at the exit-side observation point (pt. 2) 37 is observed at the entrance side. This was caused by the fact that it was larger than the point (pt. 1) 36.

FIG. 11 is a plan view and an elevational sectional view of the sound pressure distribution in the internal space of the silencer having the basic shape when resonance occurs. That is, FIG. 11 shows a plan view of a sound pressure distribution in the inner space 34 of the silencer at a frequency at which the dip (2) 41 occurs, and a sectional view cut along the yz plane.
FIG. 12 is a plan view and an elevational sectional view of the sound pressure distribution in the internal space of the silencer having the basic shape when resonance occurs. That is, FIG. 12 shows a plan view of the sound pressure distribution in the inner space 34 of the silencer at a frequency at which the dip (3) 42 occurs, and a sectional view cut along the yz plane.
FIG. 13 is a plan view and an elevational sectional view of the sound pressure distribution in the internal space of the silencer of the basic shape when resonance occurs. That is, FIG. 13 shows a plan view of the sound pressure distribution in the inner space 34 of the silencer at a frequency at which the dip (4) 43 occurs, and a sectional view cut along the yz plane.

FIG. 14 is a plan view and an elevational cross-sectional view of the sound pressure distribution in the internal space of the silencer having the basic shape when resonance occurs. That is, FIG. 14 shows a plan view of the sound pressure distribution in the inner space 34 of the silencer at a frequency at which the dip (5) 44 occurs, and a sectional view cut along the yz plane.
FIG. 15 is a plan view and an elevational cross-sectional view of the sound pressure distribution in the internal space of the silencer having the basic shape when resonance occurs. That is, FIG. 15 shows a plan view of the sound pressure distribution in the inner space 34 of the silencer at a frequency at which the dip (6) 45 occurs, and a sectional view cut along the yz plane.
FIG. 16 is a plan view and an elevational sectional view of the sound pressure distribution in the internal space of the silencer having a basic shape when resonance occurs. That is, FIG. 16 shows a plan view of a sound pressure distribution in the inner space 34 of the silencer at a frequency at which the dip (7) 46 occurs, and a sectional view cut along the yz plane.

  As shown in FIG. 11, at the frequency at which the dip (2) 41 occurs, primary resonance occurs in the radial direction of the xy plane. Similarly, FIG. 12 shows that at the frequency at which dip (3) 42 occurs, primary resonance occurs in the z-axis direction. FIG. 13 shows that at the frequency at which the dip (4) 43 occurs, the primary resonance in the radial direction of the xy plane and the primary resonance in the z-axis direction occur at the same time. FIG. 14 shows that at the frequency at which dip (5) 44 occurs, there is a secondary resonance in the radial direction of the xy plane. 15 and 16 show that the secondary resonance in the radial direction of the xy plane and the primary resonance in the z-axis direction occur at the same time at the frequency at which the dip (6) 45 and the dip (7) 46 occur. Indicates.

  Each resonance frequency f is determined by the order of resonance in the xy plane, where m is the order of resonance in the radial direction of the xy plane, n is the order of resonance in the circumferential direction, and l is the order of resonance in the z-axis direction. Using the coefficient βnm, the radius a of the expanding portion 48, and the length L ′, it can be obtained by the following equation (4).

この式（４）は、白木万博著「騒音防止設計とシミュレーション」（産業科学システムズ）、１９８７年に記載されている。

This equation (4) is described in 1987 by Hirohiro Shiraki, “Noise Prevention Design and Simulation” (Industrial Science Systems).

  FIG. 17 shows a correspondence table of coefficients βnm / π at low orders. These frequencies f move to higher frequencies as the radius a and the length L ′ of the expanding portion 48 are smaller. However, when the radius a and the length L ′ of the expansion portion 48 are reduced, the volume V of the expansion portion 48 obtained by the product is also reduced, and as a result, the lower limit frequency fmin of the silencer moves to a higher frequency. is necessary.

Here, the sound pressure distribution at the frequency at which the dip (2) 41 occurs, that is, the frequency at which primary resonance occurs in the radial direction of the xy plane will be described.
Consider a sound pressure on a straight line with y = 0 and z = 70. On this straight line, the highest sound pressure point in the range of 0 ≦ x ≦ 100 is the sound pressure at x = 0, and the sound pressure P2 at the exit-side observation point (pt.2) 37. The sound pressure Px on this straight line can be obtained by the following equation (5).

この式（５）は、白木万博著「騒音防止設計とシミュレーション」（産業科学システムズ）、１９８７年に記載されている。

This equation (5) is described in “Noise Prevention Design and Simulation” (Industrial Science Systems), 1987, by Hirohiro Shiraki.

J ₀ (t) is a zero-order Bessel function. The difference between the sound pressure level at x = 0 and the sound pressure level at x = 0 is defined as ΔNR, and is defined by the following equation (6).

FIG. 18 is a graph showing the relationship between ΔNR and x / a. The horizontal axis of FIG. 18 indicates x / a, and the vertical axis indicates ΔNR, which is the difference in sound pressure level, in dB units.
As shown in FIG. 18, a peak 50 occurs when x = 0.627a. Further, as x / a approaches from 1 to 0, ΔNR gradually increases while generating a peak 50. A position separated by 0.627a from the center, that is, a position having a radius of 62.7 mm is a node of the sound pressure distribution.

  FIG. 19 shows the result of setting the exit-side observation point (pt. 3) 51 at the position of this node and showing the characteristics of the volume reduction with respect to the frequency obtained by the acoustic analysis in the same manner as FIG. FIG. 19 is a graph showing the volume reduction characteristics with respect to the frequency at which the exit-side observation point (pt. 3) 51 is set at the node position. In FIG. 19, the horizontal axis indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. A solid line 52 indicates the result of the sound reduction characteristic at the exit-side observation point (pt. 2) 37, and a solid line 53 indicates the result of the sound reduction characteristic at the exit-side observation point (pt. 3) 51.

  The dips (2) 41 and (4) 43, which are dips due to primary resonance in the radial direction of the xy plane, are eliminated, and the volume reduction is increased. In addition, dips (5) 44, dip (6) 45, and dip (7) 46, which are dips due to secondary resonance in the radial direction of the xy plane, also show an increase in the volume reduction. This is because the sound volume level of the outer portion of the cylinder is lower than that of the central portion of the cylinder, and the volume reduction of the dip due to the secondary resonance is increased as in the case of the sound pressure distribution of the resonance.

Next, the sound pressure distribution at the frequency at which the dip (3) 42 occurs, that is, the frequency at which primary resonance occurs in the z-axis direction will be described.
Consider the sound pressure on a straight line with x = 0 and y = 0. On this straight line, in the range of 0 ≦ z ≦ 70, the highest sound pressure point is the sound pressure at z = 0 or z = 70, and the sound pressure P2 at the exit-side observation point (pt.2) 37 It is. The sound pressure Pz on this straight line can be obtained by the following equation (7).

The difference between the sound pressure level at z = z and the sound pressure level at z = z with ΔNR is defined by the following formula (8).

FIG. 20 is a graph showing the relationship between ΔNR and z / L ′. The horizontal axis in FIG. 20 indicates z / L ′, and the vertical axis indicates ΔNR, which is the difference in sound pressure level, in dB units.
A peak 54 occurs when z = 0.5 L ′. In other words, a node is generated at the position of z = 35, which is exactly the middle position in the length direction of the inflatable portion 48.

  FIG. 21 shows the result of setting the exit-side observation point (pt. 4) 55 at the position of this node and showing the characteristics of the volume reduction with respect to the frequency obtained by the acoustic analysis in the same manner as FIG. FIG. 21 is a graph showing the volume reduction characteristics with respect to the frequency at which the exit-side observation point (pt. 4) 55 is set at the node position. The horizontal axis in FIG. 21 indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. A solid line 52 indicates the result of the sound reduction characteristic at the exit-side observation point (pt. 2) 37, and a solid line 56 indicates the result of the sound reduction characteristic at the exit-side observation point (pt. 4) 55.

  Of the dip (3) 42, dip (4) 43, dip (6) 45, and dip (7) 46, the dip (3) 42 and dip (4) 43 are dip due to primary resonance in the z-axis direction. The reduced volume of dip (6) 45 and dip (7) 46 increased, but the dip itself remained. This is because the positions of the nodes of the dip (3) 42 and the dip (4) 43 are exactly at the position of z = 35, whereas the positions of the nodes of the dip (6) 45 and the dip (7) 46 are z = 35. This is because it occurred at a position outside of 35.

The reason why the position of the node does not occur at z = 35 is that the wavelength at the frequency at which the dip (6) 45 and the dip (7) 46 are generated has the same length as the length of the inlet side pipe 47, and z = 0 This is because a resonance node unrelated to the resonance node in the expansion portion 48 is generated in the vicinity and interferes with the resonance node in the expansion portion 48.
In addition, although the volume reduction is also increasing for the dip (2) 41 and the dip (5) 44 generated by resonance in which no node is generated in the z-axis direction, this is because the exit-side observation point (pt. 4) 55 is expanded. This is because the sound pressure level is lower in the outer portion than in the central portion of the cylinder at the frequency where the resonance in the radial direction of the xy plane occurs at a position away from the central portion of the cylinder of the portion 48.

  In the above description, the effect of installing the exit-side observation point at the position of the node when two types of resonance occur has been described, but this is the intersection of the nodes of the sound pressure distribution when the two types of resonance occur. FIG. 22 shows the result of setting the exit-side observation point (pt. 5) 57 and showing the characteristics of the volume reduction with respect to the frequency obtained by the acoustic analysis in the same manner as FIG. FIG. 22 is a graph showing the sound reduction characteristics with respect to the frequency at which the exit-side observation point (pt. 4) 55 is set at the node position. In FIG. 22, the horizontal axis indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. Further, the solid line 52 indicates the result of the sound reduction characteristic at the exit side observation point (pt. 2) 37, and the solid line 58 indicates the result of the sound reduction characteristic at the exit side observation point (pt. 5) 57.

  As shown in FIG. 22, there is no dip other than dip (1) 39, dip (5) 44, dip (6) 45, dip (7) 46, and the frequency from dip (1) 39 to dip (5) 44 Is a characteristic without dip.

  From the above, it has been found that it is desirable to provide an exit hole at the position of the exit-side observation point (pt. 5) 57 as a method of increasing the volume reduction of the basic shape silencer.

FIG. 23 is a sketch showing the internal space 59 of the silencer 14. FIG. 24 is a plan view and a side view showing a model example of the internal space 59 of the silencer 14.
The inner space 59 has a columnar hole 60 having a diameter of, for example, 26 mm in the inner space 34 of the silencer 25 having the basic shape shown in FIG. From the position, the shape has a shape in which four radii are spaced apart in the circumferential direction from the position to a depth of, for example, 70 mm in the radial direction. In addition, about a numerical value, a typical example is shown and it is not limited to these values.

  The shape of the silencer 14 is a combination of two types of shapes generally called side input / output type and insertion tube type. Of the four columnar holes 60, one or more holes having an exit are sufficient. About the cylindrical hole 60 with no hole, a simple protrusion may be used. The fluid outlet is formed at the central tip of the insertion tube. When the coordinates of the entrance-side observation point 61 are (x, y, z) = (0, 0, −35) and the coordinates of the exit-side observation point 62 are (0, 70, 35), The results showing the characteristics are obtained by acoustic analysis and shown in FIG. 25 in the same manner as FIG.

  FIG. 25 shows the frequency when the coordinates of the observation point 61 on the entrance side are (x, y, z) = (0, 0, −35) and the coordinates of the observation point 62 on the exit side are (0, 70, 35). It is the graph which showed the characteristic of volume reduction. In FIG. 25, the horizontal axis indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. In addition, a solid line 63 indicates the result of the sound reduction characteristic of the exit-side observation point (pt. 5) 57 with respect to the entrance-side observation point (pt. 1) 36 of the inner space 34 of the basic shape silencer, and the solid line 64 indicates the silencing. The result of the volume reduction characteristic of the exit side observation point 62 with respect to the entrance side observation point 61 of the internal space 59 of the vessel 14 is shown.

  As shown in FIG. 25, the solid line 63 and the solid line 64 are in good agreement. That is, the shape of the internal space 59 of the silencer 14 eliminates the dip due to the primary resonance in the radial direction of the xy plane and the primary resonance in the z-axis direction, and the secondary resonance in the radial direction of the xy plane. The effect which suppresses the dip by is obtained.

The reason why the above operation can be obtained in the internal space 59 of the silencer 14 will be described below.
In the z-axis direction, the expanding portion 65 is mirror-symmetric with respect to the plane of z = 35 including the cylindrical hole 60. For this reason, the node position of the sound pressure distribution when the primary resonance in the z-axis direction occurs is generated at a position of z = 35 similarly to the internal space 34 of the silencer having the basic shape. Since the position of the exit-side observation point is also the same as the node position, there is no dip caused by the primary resonance in the z-axis direction.

  Next, in the xy plane direction, the node positions of the sound pressure distribution when the primary and secondary resonances in the circumferential direction occur are respectively shown when there is no cylindrical hole 60 and when there is one cylindrical hole 60. FIG. 26 shows a table summarizing a case where there are two cylindrical holes 60 at equal intervals in the circumferential direction and four columnar holes 60 at equal intervals in the circumferential direction. FIG. 26 is a matrix showing the number of obstacles in the circular sound field, the nodes of the sound pressure distribution when the primary resonance in the circumferential direction occurs, and the positions of the nodes of the sound pressure distribution when the secondary resonance occurs. It is.

  First, when there is no cylindrical hole 60, it has the same shape as the inner space 34 of the silencer of the basic shape shown in FIG. 7, and the primary and secondary resonance nodes in the circumferential direction in the xy plane direction are exactly the same. , Passing through the center 66 of the circle. In the inflating portion 48, the position where the sound wave is input to the inflating portion 48 is the center 66 of the circle, so that resonance where the center 66 of the circle becomes a node does not occur. For this reason, in the internal space 34 of the silencer of the basic shape, there is no dip caused by the primary and secondary resonances in the circumferential direction in the xy plane direction.

  Next, in the case where there is a cylindrical hole 60, the cylindrical hole 60 becomes an obstacle with respect to the expanding portion 48, and the position of the resonance node is affected by the cylindrical hole 60 that becomes an obstacle. There are two types of nodes of primary and secondary resonances in the circumferential direction in the xy plane direction, when they occur at the position of an obstacle and when they occur at the position of the obstacle as an antinode position. First, when there is one cylindrical hole 60, both the primary resonance node and the secondary resonance node are separated from the cylindrical hole 60 when the position of the obstacle is an antinode. It occurs at a position shifted to Then, the position of the node deviates from the center 66 of the circle, the primary and secondary resonances in the circumferential direction in the xy plane direction occur, and a dip occurs in the characteristics of the volume reduction with respect to the frequency.

  Thus, when the number of obstacles is an odd number, when the nodes of the primary and secondary resonances are generated with the position of the obstacle as the antinode position, the node position is generated at a position off the center 66 of the circle. In the case of three objects, a dip occurs in the characteristic of the volume reduction with respect to the frequency as in the case of one obstacle. Therefore, the illustration in the case of three obstacles is omitted.

  Next, when there are two cylindrical holes 60, the primary resonance node occurs at the same position as the case where there is no cylindrical hole 60, but the secondary resonance node is divided into two parts. The position is away from the center 66 of the circle. Therefore, when there are two cylindrical holes 60, secondary resonance in the circumferential direction of the xy plane occurs, and a dip occurs in the characteristics of the volume reduction with respect to the frequency.

  Finally, when there are four cylindrical holes 60, neither the position of the primary resonance node nor the position of the secondary resonance node in the circumferential direction in the xy plane direction is the cylindrical hole 60. As with, it passes through the center 66 of the circle.

From the above, the number of cylindrical holes 60 needs to be four at equal intervals in the circumferential direction.
Also, the depth of the cylindrical hole 60 is not the position of 62.7 mm in the radial direction but the position of 70 mm in the radial direction because of the cylindrical hole 60, the primary direction in the radial direction in the xy plane direction. This is because the position of the resonance node is moved, and the depth of the cylindrical hole 60 is adjusted in accordance with the movement.
The shape of the hole 60 does not have to be a perfect circle as shown in the internal space 59. Even if the shape of the hole 60 is an ellipse, a square, or a rectangle, an effect equivalent to the sound reduction shown in FIG. 25 can be obtained. However, the shape of the hole 60 is preferably mirror-symmetric with respect to the plane of z = 35 and is preferably short in the z-axis direction.

The position of the center of the hole 60 does not need to be a node position as long as it is near the node position. However, with respect to the primary resonance in the radial direction of the xy plane, the effect of changing the position when the position of the hole 60 moves away from the position of the node by 5% or more with respect to the radius of the inflating portion 65 as shown in FIG. Is 20 dB or less. As for the primary resonance in the z-axis direction, as shown in FIG. 20, when the position of the hole 60 is separated from the position of the node by 3% or more with respect to the length of the inflating portion 65, the effect of changing the position is 20 dB or less.
Although it is desirable that the size of the cylindrical hole 60 is small, it is not necessary to specify the dimensions. The range of the size of the cylindrical hole 60 that can obtain the effect of the first embodiment of the present invention is shown in the description of the second embodiment.

Embodiment 2. FIG.
FIG. 27 is a sketch showing the internal space 67 of the silencer 14A according to Embodiment 2 of the present invention. FIG. 28 is a plan view and a side view showing a model example of the internal space 67 of the silencer 14A. In the second embodiment, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

.
In the first embodiment, an example in which the cylindrical hole 60 is provided has been described. However, in the second embodiment, as shown in FIGS. 27 and 28, four recesses 68 are provided at equal intervals outside the circumference. An outlet hole may be provided in the center of the recess 68.

The recess 68 has a shape obtained by extending the cylindrical hole 60 in the z-axis direction, and the shape of the silencer 14A is a change shape of a combination of a side surface input / output type and an insertion tube shape. Reduction with respect to frequency when the coordinates of the observation point 69 on the entrance side are (x, y, z) = (0, 0, −35) and the coordinates of the observation point 70 on the exit side are (0, 72.5, 35). The result showing the volume characteristic is obtained by acoustic analysis and shown in FIG. 29 in the same manner as FIG.
In FIG. 29, the coordinates of the entrance-side observation point 69 are (x, y, z) = (0, 0, −35), and the coordinates of the exit-side observation point 70 are (0, 72.5, 35). It is the graph which showed the characteristic of the volume reduction with respect to a frequency. In FIG. 29, the horizontal axis indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. In addition, a solid line 63 indicates the result of the sound reduction characteristic of the exit-side observation point (pt. 5) 57 with respect to the entrance-side observation point (pt. 1) 36 of the inner space 34 of the basic shape silencer, and a solid line 71 indicates the silencing. The result of the volume reduction characteristic of the exit side observation point 70 with respect to the entrance side observation point 69 of the internal space 67 of the vessel 14A is shown.

  As shown in FIG. 29, the solid line 63 and the solid line 71 are in good agreement. That is, an effect equivalent to that of the first embodiment can be obtained by providing a recess 68 instead of the cylindrical hole 60 shown in FIGS. 23 and 24 and providing an exit hole in the center of the recess 68. . The shape of the silencer 14A of the second embodiment is, for example, that when the silencer 14 of FIG. 1 is fixed to the fixed scroll 8 with a bolt, it can be used as a bolt hole position. There is no need to reduce the diameter of the silencer 14. The maximum volume reduction A of the expansion silencer can be obtained by the following equation (9) using the cross-sectional area S of the inlet-side pipe 47 and the cross-sectional area S ′ of the expansion portion 48 in FIG.

この式（９）は、白木万博著「騒音防止設計とシミュレーション」（産業科学システムズ）、１９８７年に記載されている。

This equation (9) is described in “Noise prevention design and simulation” (Industrial Science Systems), 1987, by Hiroshi Shiraki.

This indicates that the volume reduction is larger as the cross-sectional area of the inlet side pipe 47 is smaller and the cross-sectional area of the inflating portion 48 is larger. If the inlet side pipe 47 is made thinner, the resistance of the fluid becomes larger, so there is a limit to making it thinner, and the inflatable part 48 also needs to be housed in the sealed container 1, so that it can be made larger. There is. Therefore, not having to reduce the diameter of the silencer 14 increases the volume reduction as the silencer.
Note that the size of the recess 68 need not be the dimension shown in FIG. The size of the recess 68 that can provide the effect of the present invention will be described below.

  First, the method of determining the position of the node is shown by confirming the characteristics of the volume reduction with respect to the frequency at the observation point near the position of the node when the primary resonance in the radial direction in the xy plane direction occurs. The position of the exit-side observation point is changed in the inner space 34 of the silencer having the basic shape shown in FIGS. 7 and 8 and shown in FIGS. FIG. 30 is a sketch diagram showing a model example of the inner space 34 of the silencer having the most basic shape. FIG. 31 is a plan view and a side view showing a model example of the internal space 34 of the silencer having the most basic shape.

  The coordinates of the entrance-side observation point (pt. 1) 36 are (x, y, z) = (0, 0, −35), and the coordinates of the reference exit-side observation point (pt. 6) 72 are (0, 0). , 35), five exit-side observation points are set near the nodes of the sound pressure distribution when the primary resonance in the radial direction in the xy plane direction occurs. The coordinates of the exit-side observation point (pt. 7) 73 are (0, 60, 35), the coordinates of the exit-side observation point (pt. 8) 74 are (0, 62.5, 35), and the exit side. The coordinates of the observation point (pt. 9) 75 are (0, 65, 35), the coordinates of the exit side observation point (pt. 10) 76 are (0, 67.5, 35), and the exit side observation point (pt. 11). ) Let 77 coordinates be (0, 70, 35).

  First, FIG. 32 shows the result of the volume reduction characteristics with respect to the frequency of the exit-side observation point (pt. 6) 72 with respect to the entrance-side observation point (pt. 1) 36 as in FIG. FIG. 32 is a graph showing the volume reduction characteristics with respect to the frequency of the exit-side observation point (pt. 6) 72 with respect to the entrance-side observation point (pt. 1) 36. The horizontal axis of FIG. 32 indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. A dip 78 shown in FIG. 32 is a dip caused by the primary resonance in the radial direction in the xy plane direction. Here, the frequency of the peak 79 in FIG. 32 is fp, and the frequency of the dip 78 is fd.

  Next, an exit-side observation point (pt. 7) 73, an exit-side observation point (pt. 8) 74, an exit-side observation point (pt. 9) 75, an exit-side observation with respect to the entrance-side observation point (pt. 1) 36 The result of the sound reduction characteristics with respect to the frequency of the point (pt. 10) 76 and the exit side observation point (pt. 11) 77 is expressed as the exit side observation point (pt. 6) with respect to the entrance side observation point (pt. 1) 36. FIG. 33 to FIG. 37 show the sound reduction characteristics with respect to the frequency of 72) in the same manner as FIG.

FIG. 33 is a graph showing the characteristics of volume reduction with respect to the frequency of the exit-side observation point (pt. 7) 73 with respect to the entrance-side observation point (pt. 1) 36.
FIG. 34 is a graph showing the volume reduction characteristics with respect to the frequency of the exit-side observation point (pt. 8) 74 with respect to the entrance-side observation point (pt. 1) 36.
FIG. 35 is a graph showing the sound reduction characteristics with respect to the frequency of the exit-side observation point (pt. 9) 75 with respect to the entrance-side observation point (pt. 1).
FIG. 36 is a graph showing the volume reduction characteristics with respect to the frequency of the exit-side observation point (pt. 10) 76 with respect to the entrance-side observation point (pt. 1) 36.
FIG. 37 is a graph showing the volume reduction characteristics with respect to the frequency of the exit-side observation point (pt. 11) 77 with respect to the entrance-side observation point (pt. 1).
33 to 37, the horizontal axis indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB.

  The solid line 80 shown in FIGS. 33 to 37 shows the result of the sound reduction characteristic at the exit side observation point (pt. 6) 72, and the solid lines 81 to 85 show the exit side observation point (pt. 7) 73 and the exit side observation, respectively. The results of volume reduction characteristics at point (pt. 8) 74, exit side observation point (pt. 9) 75, exit side observation point (pt. 10) 76, and exit side observation point (pt. 11) 77 are shown. .

  For each of the peaks 86 to 90 and dips 91 to 95 in FIGS. 33 to 37, the frequency fd at which the dip occurs does not change, but the y-coordinate of the exit observation point has a primary resonance in the radial direction in the xy plane direction. The closer to y = 62.7, which is the node position of the sound pressure distribution at that time, the closer the frequency fp at which the peak occurs to the frequency fp at which the dip occurs. That is, as the absolute value | fd−fp | of the difference between the frequency fp at which this peak occurs and the frequency fd at which the dip occurs is smaller, the position of the exit-side observation point becomes higher when the primary resonance in the radial direction in the xy plane direction occurs. Among the exit-side observation points near the position of the node of the sound pressure distribution and near the position of the node of the sound pressure distribution when the primary resonance in the radial direction in the five xy plane directions occurs, the exit-side observation point ( pt.8) 74 indicates that the point is closest to the position of the node of the sound pressure distribution when the primary resonance in the radial direction in the xy plane direction occurs most.

  Next, the size of the indentation is divided into the indentation width and the indentation radial depth, and the relationship between the indentation width and the indentation radial depth with which the effect of the present invention is most obtained is shown in FIG. A confirmation method using the model shown in FIG. FIG. 38 is a plan view and a side view showing a model example of the internal space 96 of the silencer having the basic shape.

The internal space 96 shown in FIG. 38 has four recesses 97 at equal intervals in the circumferential direction, like the internal space 67 shown in FIG. The width of the indentation 97 is w1 [mm], and the radial distance from the indentation 97 to the center of the internal space 96 is _Rw1 [mm]. When the width w1 of the indentation 97 is a half power of 2 with respect to the radius, the shape of the internal space 96 is a square, so the range of w1 for forming the indentation of the silencer 14 is 0 to 141. .4.

Moreover, when the half width of _w1 becomes larger than _Rw1 , adjacent hollows 97 interfere with each other, and the shape of the present invention is not obtained. w1 was seven conditions 5,10,20,40,80,100,120, each width _was set at _{R w1} from 62.5 2.5 intervals. Volume reduction with respect to frequency when the coordinates of the entrance-side observation point 98 are (x, y, z) = (0, 0, −35) and the coordinates of the exit-side observation point 99 are (0, R _w1 , 35). Thus, the frequency fp at which the peak occurs and the frequency fd at which the dip occurs are obtained in the same manner as in FIG.

The table of FIG. 39 summarizes R _w1 when the absolute value | fd−fp | of the difference between the frequency fp at which the peak occurs and the frequency fd at which the dip occurs is the smallest. FIG. 39 is a matrix of R _w1 with respect to _w1 . Table of FIG. 39, for example, in w1 = 20, the value of the effect is the largest _{R w1} of the present invention is shown to be 72.5. Regarding the result in the space 34, the result of w1 = 0 was similarly shown in the table of FIG. 39 is converted into a graph in which the horizontal axis is R _w1 / 100 and the vertical axis is (w1 / 2) / 100, and is shown by a solid line 100 in FIG. That is, FIG. 40 is obtained by converting the result of the table in FIG. 39 into a graph.

The solid line 100 is a line extended to a point of R _w1 /100=(w1/2)/100=141.4 where the internal space 96 is a square. _{Also, R w1 / 100 = (w1} / 2) / 100 and becomes linearly 101, the unit circle 102, solid line 103 and solid line 100 was 0.05 moved to _R w1 / 100 axially, a solid line 100 _R w1 / 100 axis The broken line 104 moved by -0.05 in the direction, the intersection of the straight line 101 and the unit circle 102 is the point A105, the intersection of the unit circle 102 and the solid line 103 is the point B106, and the intersection of the solid line 103 and the _Rw1 / 100 axis is the point C107, An intersection point of the R _w1 / 100 axis and the broken line 104 is a point D108, and an intersection point of the broken line 104 and the straight line 101 is a point E109.

  A region 110 surrounded by the points A105, B106, C107, D108, and E109 is set as a range in which the effect of the present invention can be obtained. As shown in FIG. 18, the range shown in FIG. 40 is a sound pressure distribution when the primary resonance in the radial direction in the xy plane direction is generated. The increase was determined to be 20 dB or less.

  An example of the method for designing the indentation is shown in FIG. FIG. 41 is an explanatory diagram for explaining an example of a method for designing a recess. When an arbitrary point F111 is determined inside the area 110, the shape of the recess 97 is determined. The effect of this patent is large at a position close to the solid line 100, but the effect of this patent is small at a position away from the solid line 100.

In the second embodiment, the cylindrical hole 60 can be considered to have a shape in which the recess 68 is shortened in the z-axis direction. Therefore, the diameter of the cylindrical hole 60 can be designed as _w1 , and the radial distance from the cylindrical hole 60 to the center of the internal space 59 can be designed as _Rw1 . However, since the cylindrical hole 60 is shorter in the z-axis direction than the indent 68, R _w1 / 100 increases with respect to the increase of (w1 / 2) / 100, and (w1 / 2) / 100 starts from 0. In the range of 0.4, R _w1 needs to be estimated to be 2.5% smaller.

Embodiment 3 FIG.
FIG. 42 is a sketch diagram showing the internal space 112 of the silencer 14B according to Embodiment 3 of the present invention. FIG. 43 is a plan view and a side view showing a model example of the internal space 112 of the silencer 14B. In the third embodiment, differences from the first and second embodiments will be mainly described, and the same parts as those in the first and second embodiments will be denoted by the same reference numerals and the description thereof will be omitted.

.
In the second embodiment, an example in which four recesses 68 are provided at equal intervals outside the circumference and an outlet hole is provided in the center of the recess 68 has been described. However, in the third embodiment, FIG. 42 and FIG. As shown, a tapered recess 113 may be used.

When the coordinates of the entrance-side observation point 114 are (x, y, z) = (0, 0, −35) and the coordinates of the exit-side observation point 115 are (0, 75, 35), The results showing the characteristics are obtained by acoustic analysis and shown in FIG. 44 in the same manner as FIG.
In FIG. 44, the coordinates of the entrance observation point 114 are (x, y, z) = (0, 0, −35) and the coordinates of the exit observation point 115 are (0, 75, 35). It is the graph which showed the characteristic of volume reduction. The horizontal axis in FIG. 44 indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. Further, a solid line 63 shows the result of the volume reduction characteristic of the exit-side observation point (pt. 5) 57 with respect to the entrance-side observation point (pt. 1) 36 in the inner space 34 of the silencer having the basic shape, and a solid line 116 shows the result. The result of the volume reduction characteristic of the exit side observation point 115 with respect to the entrance side observation point 114 of the inner space 112 of the silencer 14B is shown.

  As shown in FIG. 44, when the solid line 63 and the solid line 116 are compared, the solid line 116 is in good agreement except that a dip 117 is generated. FIG. 45 shows a plan view of the sound pressure distribution in the internal space 112 when the dip 117 occurs and an elevation view as seen from the x-axis direction. That is, FIG. 45 is a plan view and an elevation view of the sound pressure distribution in the internal space 112 of the silencer 14B when resonance occurs. This is a resonance of a combination of a secondary resonance in the x-axis direction and a secondary resonance in the y-axis direction. The frequency f at which the dip 117 is generated can be obtained by the following equation (10) using the length Lx in the x-axis direction and the length Ly in the y-axis direction of the internal space 112 where the depression 113 is present.

この式（１０）は、白木万博著「騒音防止設計とシミュレーション」（産業科学システムズ）、１９８７年に記載されている。

This equation (10) is described in “Noise prevention design and simulation” written by Masahiro Shiraki (Industrial Science Systems), 1987.

  This resonance is caused by the fact that the internal space 112 with the recess 113 approaches a rectangular sound field due to the taper of the recess 113. That is, by providing the tapered depression 113 shown in FIGS. 42 and 43, a dip 117 is generated due to the resonance of the combination of the secondary resonance in the x-axis direction and the secondary resonance in the y-axis direction. The dip due to the primary resonance in the radial direction and the primary resonance in the z-axis direction can be eliminated.

The shape of the third embodiment is different from the first and second embodiments, and greatly extends from the internal space 112 through the outlet to the external space. It is unlikely that resonance, resonance in the indentation 68 in the second embodiment, will occur.
It should be noted that the shape of the recess 113 does not have to be a plane, and the same effect can be obtained even if it is configured by a recess 118 surrounded by a curved surface as shown in FIG. FIG. 46 is a sketch diagram showing the internal space of the silencer according to Embodiment 3 of the present invention.

Embodiment 4 FIG.
FIG. 47 is a sketch showing the internal space 119 of the silencer 14C according to Embodiment 4 of the present invention. FIG. 48 is a plan view and a side view showing a model example of the internal space 119 of the silencer 14C. In the fourth embodiment, differences from the first to third embodiments will be mainly described, and the same parts as those in the first to third embodiments will be denoted by the same reference numerals and the description thereof will be omitted.

  In the third embodiment, the tapered recess 113 is described as an example. However, as shown in FIGS. 47 and 48, the tapered shape may be a plane as shown by the plane 120 in the internal space 119. Good. The plane 120 is a shape obtained by extending the cylindrical hole 60 in a plane direction perpendicular to the height direction of the cylindrical hole, and the shape of the silencer 14C is a combination of a side input / output type and an insertion tube type. The change shape.

When the coordinates of the entrance-side observation point 121 are (x, y, z) = (0, 0, −35) and the coordinates of the exit-side observation point 122 are (0, 75, 35), The results showing the characteristics are obtained by acoustic analysis and shown in FIG. 49 in the same manner as FIG.
FIG. 49 shows the frequency when the coordinates of the entrance observation point 121 are (x, y, z) = (0, 0, −35) and the coordinates of the exit observation point 122 are (0, 75, 35). It is the graph which showed the characteristic of volume reduction. The horizontal axis in FIG. 49 indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. In addition, a solid line 63 indicates a result of a sound reduction characteristic of the exit-side observation point (pt. 5) 57 with respect to the entrance-side observation point (pt. 1) 36 of the interior space 34 of the basic shape silencer, and a solid line 123 indicates the silencing. The result of the volume reduction characteristic of the exit side observation point 122 with respect to the entrance side observation point 121 of the internal space 119 of the vessel 14C is shown.

  As shown in FIG. 49, when the solid line 63 and the solid line 123 are compared, the black solid line 123 has a dip 124, and in the frequency band lower than the frequency at which the dip 124 is generated, the dip 124 is generally larger than the gray solid line 63. The volume is low. FIG. 50 shows a plan view of the sound pressure distribution in the internal space 119 of the silencer 14C when the dip 124 is generated and an elevation view seen from the x-axis direction. That is, FIG. 50 is a plan view and an elevation view of the sound pressure distribution in the internal space of the silencer 14C when resonance occurs. The frequency f generated by the dip 124 is obtained using the length Lx in the x-axis direction and the length Ly in the y-axis direction of the internal space 119 having the plane 120 in the same manner as the resonance frequency of the dip 117 shown in FIG. be able to.

  Further, the overall volume reduction is reduced because the cross-sectional area S ′ of the expansion portion 125 of the internal space 119 where the plane 120 is present is smaller than the cross-sectional area S ′ of the expansion portion 48 of the basic space 34. This is because the maximum volume reduction A has decreased. That is, by providing the plane 120 shown in FIGS. 47 and 48, a dip 120 is generated due to the resonance of the combination of the secondary resonance in the x-axis direction and the secondary resonance in the y-axis direction, and the overall volume reduction is reduced. However, the dip due to the primary resonance in the radial direction in the xy plane direction and the primary resonance in the z-axis direction can be eliminated.

The shape of the fourth embodiment is different from the first to third embodiments, and it is not necessary to form an insertion tube or a recess in the silencer, so that the productivity is high.
Note that the size of the flat surface 120 is not necessarily the size shown in FIG. The range in which the effect of this patent is obtained is on the line of the arc AB126 excluding the point B106 shown in FIG. An example of the plane design method is shown in FIG. FIG. 51 is an explanatory diagram for explaining an example of a plane design method. When an arbitrary point G127 is determined on the line of the arc AB126 excluding the point B106, the shape of the plane 120 is determined. The effect of this patent is large at a position close to the point A105, but the effect of this patent is small at a position away from the point A105.
Although it is possible to provide an arbitrary point G127 on the solid line 101, it is not desirable because the internal space is reduced, the lower limit frequency fmin of the silencer is moved to a higher frequency, and the maximum volume reduction A is reduced.

Embodiment 5. FIG.
FIG. 52 is a sketch showing the internal space 128 of the silencer 14D according to Embodiment 5 of the present invention. FIG. 53 is a plan view and a side view showing a model example of the internal space 128 of the silencer 14D. In the fifth embodiment, differences from the first to fourth embodiments will be mainly described, and the same parts as those in the first to fourth embodiments will be denoted by the same reference numerals and description thereof will be omitted.

  In the second embodiment, the example in which the silencer 14A is provided in the z-axis direction like the recess 68 in the internal space 67 has been described. However, as shown in FIGS. 52 and 53, the recess 129 in the internal space 128 is provided. Further, it may be provided in an annular shape in the circumferential direction. The recess 129 has a shape obtained by extending the cylindrical hole 60 in the circumferential direction, and the shape of the silencer 14D is a change shape of a combination of a side surface input / output type and an insertion tube type.

When the coordinates of the entrance-side observation point 130 are (x, y, z) = (0, 0, −35) and the coordinates of the exit-side observation point 131 are (0, 70, 35), The results showing the characteristics are obtained by acoustic analysis and shown in FIG. 54 in the same manner as FIG.
FIG. 54 shows the frequency when the coordinates of the observation point 130 on the entrance side are (x, y, z) = (0, 0, −35) and the coordinates of the observation point 131 on the exit side are (0, 75, 35). It is the graph which showed the characteristic of volume reduction. In FIG. 54, the horizontal axis indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. In addition, a solid line 63 indicates a result of a sound reduction characteristic of the exit-side observation point (pt. 5) 57 with respect to the entrance-side observation point (pt. 1) 36 of the interior space 34 of the basic shape silencer, and a solid line 132 indicates the silencing. The result of the volume reduction characteristic of the exit side observation point 131 with respect to the entrance side observation point 130 of the internal space 128 of the vessel 14D is shown.

  As shown in FIG. 54, when comparing the solid line 63 and the solid line 132, the black solid line 132 has a dip 133 having a characteristic of reduced sound volume due to secondary resonance in the radial direction in the xy plane direction. It is in good agreement except for moving to lower frequencies. This is because the provision of the annular recess 129 has an effect on the sound pressure distribution when resonance occurs. That is, by providing the annular recess 129 shown in FIGS. 52 and 53, the dip 133 due to the secondary resonance in the radial direction in the xy plane direction has a lower frequency than the dip (5) 44 of the same resonance in the basic shape. However, the dip due to the primary resonance in the radial direction in the xy plane direction and the primary resonance in the z-axis direction can be eliminated.

The shape of the fifth embodiment is different from the first to fourth embodiments, and the maximum number of outlet holes that can be opened is not limited to four. Further, when two or more exit holes are provided, in the first to fourth embodiments, the positional relationship can be provided only at intervals of 90 degrees, but the shape of the fifth embodiment has a high degree of freedom in the positional relationship of the holes. .
Note that the size of the annular recess 129 is not necessarily the size shown in FIG. The size of the annular recess 129 that can provide the effects of the present invention will be described below.

  Similarly to the second embodiment, the width of the annular recess and the depth in the radial direction of the recess are divided, and the radial depth of the annular recess in which the effect of the present invention is most obtained with respect to the width of the recess. The confirmation method will be described with reference to the model shown in FIG. FIG. 55 is a plan view and a side view showing a model example of the internal space 134 of the silencer 14D.

In the internal space 134 shown in FIG. 55, there is an annular recess 135 as in the internal space 128 shown in FIG. The width of the annular recess 135 is w2 [mm] and the radius of the inner diameter is R _w2 [mm]. The w2 was set to 7 conditions of 5, 10, 20, 40, 50, 60, and 65, and R _w2 was set at intervals of 62.5 to 2.5 for each width. Volume reduction with respect to frequency when the coordinates of the entrance-side observation point 136 are (x, y, z) = (0, 0, −35) and the coordinates of the exit-side observation point 137 are (0, R _w2 , 35). Thus, the frequency fp at which the peak occurs and the frequency fd at which the dip occurs are obtained in the same manner as in FIG.

FIG. 56 shows a table of R _w1 when the absolute value | fd−fp | of the difference between the frequency fp at which the peak occurs and the frequency fd at which the dip occurs is the smallest. FIG. 56 is a matrix of R _w2 with respect to _w2 . Regarding the result in the space 34, the result of w1 = 0 is similarly shown in the table of FIG. The results of the table in FIG. 56 are converted into a graph in which the horizontal axis is R _w2 / 100 and the vertical axis is (w2 / 2) / 70, and is shown as a solid line 138 in FIG. The solid line 138 is extended to a point where (R _{w2 /} 100, ( _w2 / ₂ ) / 70) = (62.5, 1). That is, FIG. 57 is obtained by converting the result of the table in FIG. 56 into a graph.

Also, x = 1 (−1 ≦ y ≦ 1), x = −1 (−1 ≦ y ≦ 1), y = 1 (−1 ≦ x ≦ 1), and y = −1 (−1 ≦ x). ≦ 1) the four sides to the square 139, solid line 140 and solid line 138 was 0.05 moved to _R w2 / 100 axially, dashed 141 the solid line 138 was -0.05 moved to _R w2 / 100 axially, square 139 and the point of intersection of the solid line 140 H142, solid line 140 and _R w2 / 100 point to the intersection of the axis _I143, R w2 / 100 intersection points between the shaft and the dashed line 141 J144, a point K145 an intersection dashed 141 and the square 139 To do.

  A region 146 surrounded by the point H142, the point I143, the point J144, and the point K145 is set as a range in which the effect of the present invention can be obtained. The range shown in FIG. 57 is that, as shown in FIG. 18, in the sound pressure distribution when the primary resonance in the radial direction in the xy plane direction occurs, the decrease in volume is increased at a position away from the node position by 0.05 or more. Was determined to be 20 dB or less.

  FIG. 58 shows an example of a method for designing an annular recess. FIG. 58 is an explanatory diagram for explaining an example of a method for designing a recess. When an arbitrary point L147 is determined within the region 146, the shape of the annular recess 135 is determined. The effect of this patent is large at a position close to the solid line 138, but the effect of this patent is small at a position away from the solid line 138.

Embodiment 6 FIG.
FIG. 59 is a sketch showing the internal space 148 of the silencer 14E according to Embodiment 6 of the present invention. FIG. 60 is a plan view and a side view showing a model example of the internal space 148 of the silencer 14E. In the sixth embodiment, differences from the first to fifth embodiments will be mainly described, and the same parts as those in the first to fifth embodiments will be denoted by the same reference numerals and the description thereof will be omitted.

  In the fifth embodiment, the recess 129 in the internal space 128 has been described as an example. However, as shown in FIGS. 59 and 60, a taper may be provided as in the recess 149 in the internal space 148.

When the coordinates of the entrance-side observation point 150 are (x, y, z) = (0, 0, −35) and the coordinates of the exit-side observation point 151 are (0, 65, 35), The results showing the characteristics are obtained by acoustic analysis and shown in FIG. 61 in the same manner as FIG.
In FIG. 61, the coordinates of the entrance observation point 150 are (x, y, z) = (0, 0, −35) and the coordinates of the exit observation point 151 are (0, 65, 35). It is the graph which showed the characteristic of volume reduction. In FIG. 61, the horizontal axis indicates the frequency in Hz, and the vertical axis indicates the volume reduction in dB. In addition, a solid line 63 indicates the result of the sound reduction characteristic of the exit-side observation point (pt. 5) 57 with respect to the entrance-side observation point (pt. 1) 36 of the inner space 34 of the basic shape silencer, and a solid line 152 indicates the silencing. The result of the volume reduction characteristic of the exit side observation point 151 with respect to the entrance side observation point 150 of the internal space 148 of the container 14E is shown.

  As shown in FIG. 61, when comparing the solid line 63 and the solid line 152, they are in good agreement except that the volume reduction of the solid line 152 is generally low. This is because the substantial cross-sectional area S 'of the expansion portion 153 of the inner space 145 of the silencer provided with the tapered annular recess 149 is reduced, and as a result, the maximum volume reduction A is reduced. That is, by providing the tapered annular recess 149 shown in FIGS. 59 and 60, the overall sound reduction is reduced, but the same effect as in the first embodiment can be obtained.

The shape of the sixth embodiment is different from the first embodiment, the second embodiment, and the fifth embodiment, like the shape of the third embodiment, and greatly extends from the internal space 82 through the outlet to the external space. Therefore, there is a low possibility that the resonance in the cylindrical hole 60 in the first embodiment and the resonance in the recess 68 and the annular recess 129 in the second and fifth embodiments will occur.
It should be noted that the shape of the recess 149 does not have to be configured in the shape of a linear z-axis rotating body, but may be implemented even if it is configured in the shape of a curved z-axis rotating body as in the recess 154 shown in FIG. There is an effect similar to the sixth aspect. FIG. 62 is a sketch showing the internal space of the silencer 14E.

  DESCRIPTION OF SYMBOLS 1 Airtight container, 2 Stator, 3 Rotor, 4 Motor element, 5 Crankshaft, 6 Compressor element, 7 Frame, 8 Fixed scroll, 9 Space, 10 Swing scroll, 11 Bearing, 12 Discharge hole, 13 Discharge valve , 14 Silencer, 14A Silencer, 14B Silencer, 14C Silencer, 14D Silencer, 14E Silencer, 15 Outlet, 16 Space, 17 Space, 18 Cylindrical part, 19 Insertion tube, 20 Top plate, 21 Flat plate, 22 holes, 23 shafts, 24 bolt holes, 25 silencer, 26 cylindrical part, 27 blowout holes, 28 top plate, 29 flat plate, 30 bolt holes, 31 cylindrical space, 32 inlet side observation point, 33 outlet side observation point, 34 Space, 35 Origin, 36 Entrance-side observation point, 37 Exit-side observation point, 38 Entrance-side end face, 47 Entrance-side pipe line, 48 Expansion part, Section 49, 51 Exit-side view Station, 55 Exit-side observation point, 57 Exit-side observation point, 59 Internal space, 60 holes, 61 Entrance-side observation point, 62 Exit-side observation point, 65 Expansion part, 66 Center, 67 Internal space, 68 Recess, 69 Entrance Side station, 70 Exit side station, 72 Exit side station, 73 Exit side station, 74 Exit side station, 75 Exit side station, 76 Exit side station, 77 Exit side station, 82 Interior space, 96 interior space, 97 indentation, 98 entrance-side observation point, 99 exit-side observation point, 100 scroll compressor, 112 interior space, 113 indentation, 114 entrance-side observation point, 115 exit-side observation point, 119 interior space, 120 plane, 121 Entrance side observation point, 122 Exit side observation point, 125 Expansion part, 128 Internal space, 129 Indentation, 130 Entrance side observation point, 131 Exit side observation point, 1 4 internal space, recess 135, 136 inlet side observation point, 137 outlet observation point, 145 inner space 148 internal space, 149 recess, 150 inlet side observation point, 151 outlet observation point, 153 expansion unit, 154 dimples.

Claims (7)

In a silencer equipped with a cylindrical expansion part and attached to a compressor,
Four protrusions having the same shape projecting toward the center of the inflating portion are provided in the vicinity of the center in the height direction of the inflating portion and in the radial direction of the inflating portion at equal intervals in the circumferential direction,
For the inflating part,
A fluid inlet is positioned in the middle of the compressor element side end face of the compressor;
A silencer, wherein a fluid outlet is provided at one or more of the protrusions. In a silencer equipped with a cylindrical expansion part and attached to a compressor,
An annular protrusion projecting toward the center of the inflating portion is provided in the vicinity of the center in the height direction of the inflating portion and uniformly in the circumferential direction,
For the inflating part,
A fluid inlet is positioned in the middle of the compressor element side end face of the compressor;
A muffler in which a fluid outlet is provided in the projection. In a silencer equipped with a cylindrical expansion part and attached to a compressor,
The primary resonance in the axial direction within a range of ± 5% in the radial direction from the position of the node of the sound pressure distribution when the primary resonance in the radial direction in the plane occurs. Within the range of ± 3% in the height direction from the position of the node of the sound pressure distribution at the time of occurrence of the sound pressure distribution, the same shape of the insertion tube at equal intervals in the circumferential direction 4 in the radial direction of
For the inflating part,
A fluid inlet is positioned in the middle of the compressor element side end face of the compressor;
The silencer which makes the exit of the fluid any one or more of the said insertion pipes. In a silencer equipped with a cylindrical expansion part and attached to a compressor,
The primary resonance in the axial direction within a range of ± 5% in the radial direction from the position of the node of the sound pressure distribution when the primary resonance in the radial direction in the plane occurs. Within the range of ± 3% of the height of the inflatable portion from the position of the sound pressure distribution node when the indentation occurs, the indentations of the same shape are arranged at equal intervals in the circumferential direction. Four on the outer surface,
For the inflating part,
A fluid inlet is positioned in the middle of the compressor element side end face of the compressor;
One or more of the recesses are outlets for fluid. In a silencer equipped with a cylindrical expansion part and attached to a compressor,
The primary resonance in the axial direction within a range of ± 5% in the radial direction from the position of the node of the sound pressure distribution when the primary resonance in the radial direction in the plane occurs. The plane of the same shape is equidistantly spaced in the circumferential direction within a range of ± 3% in the height direction from the position of the node of the sound pressure distribution at the time of occurrence of Four on the outer surface,
For the inflating part,
A fluid inlet is positioned in the middle of the compressor element side end face of the compressor;
A silencer having a fluid outlet at a central position of any one or more of the planes. In a silencer equipped with a cylindrical expansion part and attached to a compressor,
The primary resonance in the axial direction within a range of ± 5% in the radial direction from the position of the node of the sound pressure distribution when the primary resonance in the radial direction in the plane occurs. The annular recess is uniformly distributed in the circumferential direction of the inflating portion within a range of ± 3% in the height direction from the position of the node of the sound pressure distribution when the noise occurs. Provided,
For the inflating part,
A fluid inlet is positioned in the middle of the compressor element side end face of the compressor;
One or more silencers provided with a fluid outlet at a central position in the height direction of the recess. The muffler according to any one of claims 1 to 6,
A compressor fixed to the fixed scroll such that a discharge hole of the fixed scroll constituting the compressor element is located at a central position of the silencer.

Images