WO2017183367A1

WO2017183367A1 - Rotary compressor

Info

Publication number: WO2017183367A1
Application number: PCT/JP2017/010498
Authority: WO
Inventors: 俊輔薬師寺; 郁男江崎
Original assignee: 三菱重工サーマルシステムズ株式会社
Priority date: 2016-04-21
Filing date: 2017-03-15
Publication date: 2017-10-26
Also published as: JP6683532B2; CN108496009A; EP3399193A4; EP3399193A1; JP2017194016A

Abstract

This rotary compressor 1 is provided with a rotating shaft 3, a rotary-type compression mechanism 4, and a muffler 10 which is disposed around the axis of the rotating shaft 3. The muffler 10 is provided with: a muffler body 11 for receiving a compressed refrigerant therein; and a flow passage wall 12 for forming a discharge flow passage 100 between the flow passage wall 12 and the rotating shaft 3 or a bearing section 6B, the discharge flow passage 100 having a predetermined length and allowing the refrigerant to flow to the outside of the muffler 10 in the axial direction of the rotating shaft 3. The discharge flow passage 100 has: a first flow passage section 101 located at a part in the circumferential direction D1 of the rotating shaft 3; and a second flow passage section 102 which is adjacent to the first flow passage section 101 in the circumferential direction D1, has a greater dimension in the radial direction of the rotating shaft 3 than the first flow passage section 101, and has a greater cross-sectional area than the first flow passage section 101.

Description

Rotary compressor

The present invention relates to a rotary compressor provided with a rotary compression mechanism and a discharge muffler.

A rotary compressor includes a rotary shaft, a piston rotor provided on the rotary shaft, a rotary compression mechanism having a cylinder, a muffler for suppressing noise caused by pulsation (pressure fluctuation) of compressed refrigerant gas, a housing, and (E.g., Patent Document 1).
The refrigerant gas compressed by the rotary type compression mechanism is discharged to the inside of the muffler through the discharge port formed in the member closing the opening of the cylinder, and is passed through the gap between the reduced diameter portion of the muffler and the rotation shaft. It is discharged into the space in the housing.
In Patent Document 1, the gap (the outlet of the muffler) formed on the outer periphery of the rotation shaft is in a symmetrical position with the discharge port (the inlet of the muffler) from the inside of the cylinder around the rotation shaft. Pulsation of the refrigerant gas discharged inward is reduced by the muffler.

Patent No. 3941809

Although the muffler mainly reduces pulsation of a specific frequency component, it is difficult to sufficiently reduce pulsation of other frequency components.
Pulsations that are not sufficiently reduced even by the muffler are discharged to the outside of the muffler, and resonating in the space in the housing leads to noise.

Then, an object of this invention is to provide the rotary compressor which can also reduce the pulsation which is not fully reduced inside a muffler.

The rotary compressor according to the present invention comprises a rotary compression mechanism having a rotary shaft, a piston rotor provided on the rotary shaft, and a cylinder on which the piston rotor is disposed, and a muffler disposed around the rotary shaft. The muffler is provided along the axial direction of the rotation axis between the muffler body that receives the fluid compressed by the compression mechanism inward and the bearing portion positioned around the rotation axis or the axis of the rotation axis. And a flow passage wall forming a discharge flow passage of a predetermined length for discharging the fluid to the outside, and the discharge flow passage includes a first flow passage portion positioned in a part of the circumferential direction of the rotation shaft; A second flow passage portion adjacent to the first flow passage portion in the direction and having a larger dimension in the radial direction of the rotation axis than the first flow passage portion and a larger cross-sectional area than the first flow passage portion; It is characterized by

The flow velocity of the fluid flowing through each of the first flow path portion and the second flow path portion is different due to the difference in cross sectional area between the first flow path portion and the second flow path portion. Therefore, the phase of the pressure fluctuation of the fluid flowing into each of the first flow channel unit and the second flow channel unit is shifted, and the pressure fluctuation of the fluid flowing out of each of the first flow channel unit and the second flow channel unit interferes I will cancel each other.

In the rotary compressor of the present invention, the discharge flow passage preferably has a plurality of second flow passage portions.

Preferably, in the rotary compressor of the present invention, the cross-sectional areas of the plurality of second flow path portions are different from each other.

In the rotary compressor of the present invention, the discharge flow path is formed over the entire circumference around the axis of the rotation shaft, and the plurality of first flow path portions and the plurality of second flow paths alternately arranged in the circumferential direction It is preferable to have a part.

In the rotary compressor of the present invention, it is preferable that a portion of the flow path wall forming the second flow path portion is formed in a substantially C-shaped cross section or a substantially V-shaped cross section.

The rotary compressor according to the present invention comprises a rotary compression mechanism having a rotary shaft, a piston rotor provided on the rotary shaft, and a cylinder on which the piston rotor is disposed, and a muffler disposed around the rotary shaft. The muffler is provided along the axial direction of the rotation axis between the muffler body that receives the fluid compressed by the compression mechanism inward and the bearing portion positioned around the rotation axis or the axis of the rotation axis. And a flow passage wall forming a discharge flow passage of a predetermined length for discharging the fluid to the outside, the discharge flow passage being a first flow passage portion positioned in a part of the circumferential direction of the rotation shaft; And a second flow passage portion having a cross-sectional area larger than that of the first flow passage portion, and the first flow passage portion protrudes radially outward from the second flow passage portion.

In the rotary compressor of the present invention, the length of the discharge channel x _0, the flow velocity of the fluid in the first flow path part v _1, the flow velocity ratio v ₁ of the flow velocity of the fluid in the second flow path part alpha, predetermined Assuming that the frequency of f is f, it is preferable that α = n (v ₁ / 2fx ₀ ) +1, where n is a natural number.

According to the rotary compressor of the present invention, since the pulsation which is not sufficiently reduced inside the muffler can be reduced, the noise caused by the pulsation can be suppressed.

It is a longitudinal section of a rotary compressor concerning a 1st embodiment. (A) is a figure which expands and shows a part of rotary compressor shown in FIG. (B) is a figure which shows the discharge flow path of a muffler. It is a top view of a muffler shown in Drawing 2 (a). (A) is a figure which shows the pulsation of the fluid which flows through the 1st flow-path part of the discharge flow path of a muffler, (b) shows the pulsation of the fluid which flows through the 2nd flow-path part of the discharge flow path of a muffler. FIG. It is a top view of the muffler with which the rotary compressor concerning a 2nd embodiment was equipped. It is a top view of the muffler with which the rotary compressor concerning the modification of the present invention was equipped. It is a top view of the muffler with which the rotary compressor concerning another modification of the present invention was equipped. It is a top view of the muffler with which the rotary compressor concerning the modification of the present invention was equipped.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

First Embodiment
The compressor 1 shown in FIG. 1 sucks the gas refrigerant in an accumulator (gas-liquid separator) (not shown) through the

pipes

8 and 9 and compresses it by the compression mechanism 4.
The compressor 1 and the accumulator constitute a refrigeration cycle apparatus such as an air conditioner or a refrigerator, and are connected to a not-shown refrigerant circuit through which the refrigerant circulates.

The compressor 1 is driven by a motor 2 as a motive power source, a rotary shaft 3 (crankshaft) rotated by a rotary drive force output from the motor 2, and a rotary drive force transmitted via the rotary shaft 3. The rotary compression mechanism 4, the

mufflers

10 and 20 disposed around the axis of the rotary shaft 3, and the housing 5.
The

mufflers

10 and 20 suppress noise due to pulsation of the refrigerant compressed by the compression mechanism 4.

The housing 5 accommodates the motor 2, the rotary shaft 3, the compression mechanism 4, and the

mufflers

10 and 20 and is formed in a cylindrical shape.
The motor 2 includes a stator 2A fixed to the inner peripheral portion of the housing 5 and a rotor 2B disposed inside the stator 2A. The rotor 2B rotates with respect to the stator 2A by energization to a coil 2C provided on the stator 2A.

The rotating shaft 3 is coupled to the rotor 2B and protrudes downward below the rotor 2B, the upper crank pin 3B eccentric to the axis of the main shaft 3A, and the axis of the main shaft 3A. And an eccentric lower crank pin 3C. The lower crank pin 3C is decentered with respect to the axial center of the rotating shaft 3 in a direction opposite to the upper crank pin 3B (180 °).
The upper crank pin 3 B is disposed in the upper cylinder 412 of the compression mechanism 4, and the lower crank pin 3 C is disposed in the lower cylinder 422 of the compression mechanism 4.

The compression mechanism 4 (FIG. 1) will be described.
The so-called twin rotary type compression mechanism 4 includes an upper compression mechanism 41, a lower compression mechanism 42, a partition plate 4A, and an upper bearing 6 and a lower bearing 7 that rotatably support the rotary shaft 3.
The partition plate 4A partitions the inside of the cylinder 412 of the upper compression mechanism 41 and the inside of the cylinder 422 of the lower compression mechanism 42.

The upper compression mechanism 41 includes an upper piston rotor 411 provided on the upper crank pin 3B, an upper cylinder 412 on which the upper piston rotor 411 is disposed, and an upper muffler 10 disposed around the axis of the main shaft portion 3A. It is done.
The upper piston rotor 411 is fitted to the outer peripheral portion of the upper crank pin 3 B, and is pivoted within the upper cylinder 412 as the upper piston rotor 411 rotates.
The refrigerant is drawn into the upper cylinder 412 through the pipe 8.

The upper bearing 6 has a butting portion 6A that is butted against the upper end surface of the upper cylinder 412, and a cylindrical bearing portion that protrudes upward from the butting portion 6A and is positioned around the axis of the rotary shaft 3 (main shaft portion 3A) And 6B. The abutment portion 6A is fixed to the inner circumferential portion of the housing 5.
An upper cylinder 412, an upper muffler 10, a lower cylinder 422, and a lower muffler 20 are integrally assembled to the upper bearing 6 by bolts 11B.

The refrigerant drawn into the upper cylinder 412 is compressed in a space forward in the rotational direction of a blade (not shown) pressed against the outer peripheral portion of the revolving upper piston rotor 411. The compressed refrigerant is discharged into the upper muffler 10 through the discharge port (not shown) formed in the abutting portion 6A of the upper bearing 6, and further, through the discharge flow path 100 between the upper muffler 10 and the bearing portion 6B. It is discharged into the space below the motor 2 in the housing 5.

Similar to the upper compression mechanism 41, the lower compression mechanism 42 is disposed around the lower piston rotor 421 provided on the lower crankpin 3C, the lower cylinder 422 in which the lower piston rotor 421 is disposed, and the main shaft 3A. The lower muffler 20 is included.
Gas refrigerant is drawn into the lower cylinder 422 through the pipe 9.

The lower bearing 7 has a butt portion 7A that is butted against the lower end surface of the lower cylinder 422, and a cylindrical bearing portion that protrudes downward from the butt portion 7A and is positioned around the axis of the rotary shaft 3 (spindle portion 3A) And 7B.

The refrigerant drawn into the lower cylinder 422 is compressed as the lower piston rotor 421 turns and is discharged into the lower muffler 20 through a discharge port (not shown) formed in the abutting portion 7A of the lower bearing 7. The refrigerant discharged into the lower muffler 20 is discharged to the internal space of the housing 5 through the discharge flow passage 200 between the lower muffler 20 and the bearing portion 7B, and is further formed in the abutting portion 6A of the upper bearing 6. The air passes through the notches 61A and a hole (not shown), and is discharged into the space in the housing 5 below the motor 2.

As described above, the refrigerant compressed by the upper compression mechanism 41 and the lower compression mechanism 42 is discharged into the space in the housing 5 below the motor 2. The refrigerant flows to a space above the motor 2 through the notches provided in the stator 2A and the rotor 2B, and is discharged into the refrigerant circuit through the discharge pipe 5A provided in the upper part of the housing 5.

The upper compression mechanism 41 and the lower compression mechanism 42 respectively discharge the refrigerant from the discharge port with pressure fluctuation (pulsation) according to the swing cycle of the

piston rotors

411 and 421. The pulsations of the compressed refrigerant ejected respectively to the

mufflers

10 and 20 through the discharge ports by the upper compression mechanism 41 and the lower compression mechanism 42 are reduced in the

mufflers

10 and 20, respectively.
Here, pulsations that are not sufficiently reduced even by the

mufflers

10 and 20 are discharged to the outside of the

mufflers

10 and 20, and if resonating in the space below the motor 2 in the housing 5, it leads to noise.
Therefore, the compressor 1 of the present embodiment also discharges the discharge flow of the refrigerant flowing out of the

mufflers

10 and 20 to the outside of the

mufflers

10 and 20 in order to reduce pulsations that are not sufficiently reduced inside the

mufflers

10 and 20. The features are in the

paths

100 and 200.

First, the configuration of the upper muffler 10 (hereinafter, the muffler 10) will be described.
As shown in FIG. 2 (a), the muffler 10 is formed between the muffler main body 11 forming a space with the abutment portion 6A of the upper bearing 6 and the bearing portion 6B of the upper bearing 6 A flow passage wall 12 is provided which forms a discharge flow passage 100 through which the refrigerant flows out to the outside. The flow path wall 12 is a peripheral portion of the opening 10 </ b> A formed in the planar central portion of the muffler 10. The bearing portion 6B of the upper bearing 6 is passed through the opening 10A.
The muffler main body 11 and the flow path wall 12 are integrally formed, for example, by deep drawing from a metal material such as an aluminum alloy.

The muffler main body 11 receives the compressed refrigerant compressed in the upper cylinder 412 and ejected from the discharge port (not shown) to the inside, and reduces the pulsation of the compressed refrigerant. The space inside the muffler main body 11 acts as a resistance according to the space volume for the refrigerant ejected into the muffler main body 11, so the pulsation of the refrigerant is attenuated by the muffler 10.
The muffler main body 11 extends radially outward of the flow path wall 12 with a predetermined diameter, and is formed in a circular shape in a plan view. Radially outer end portions of the muffler main body 11 are fastened to the upper bearing 6 by bolts 11B at a plurality of circumferential positions. The bolt 11B is omitted in FIG.

The inner peripheral end 111 of the muffler main body 11 is located above the abutting portion 6A and is continuous with the flow path wall 12. Here, although the inner peripheral end 111 of the muffler main body 11 is continuous with the flow path wall 12 via the curved portion 112, the inner peripheral end 111 may be directly continuous with the flow path wall 12. The curved portion 112 is curved so as to be convex upward from the inner peripheral end 111.
The size and volume of the muffler main body 11 are appropriately determined so as to be compatible with the main frequency component of the pulsation of the compressed refrigerant. The main frequency components are, for example, in the middle frequency band of 500 Hz to 1 kHz, which is susceptible to noise.

An inner space of the muffler main body 11 may be divided into an inner compartment which primarily receives the refrigerant ejected from the discharge port, and an outer compartment which secondarily receives the refrigerant from the compartment. Even with such a two-stage muffler, the same effects as the muffler 10 of the present embodiment can be obtained by configuring the discharge flow path 100 that causes the refrigerant to flow out of the outer section to the outside of the muffler as described below. Can.

The flow path wall 12 is connected to the muffler main body 11 via the curved portion 112. The flow path wall 12 rises in the axial direction of the bearing portion 6B from the same height over the entire circumference. The height of the upper end of the flow path wall 12 is constant over the entire circumference.
Between the inner peripheral portion of the flow path wall 12 and the outer peripheral portion of the bearing portion 6B, as shown in FIG. 2B, a discharge flow path 100 having a length corresponding to the height of the flow path wall 12 is rotated. It is formed along the axial direction of the axis 3.

Depending on the height of the entire muffler 10, the flow path wall 12 may face the outer peripheral portion of the rotation shaft 3 instead of the bearing portion 6B. In such a case, the discharge flow passage 100 is formed between the inner circumferential portion of the flow passage wall 12 and the outer circumferential portion of the rotary shaft 3.

The lower muffler 20 (FIG. 1) is configured to have substantially the same shape as the upper muffler 10, and is disposed around the axis of the lower bearing 7 in a direction that is inverted in the vertical direction from the upper muffler 10.
The lower muffler 20 is provided with a flow passage wall 22 between the muffler main body 21 and the bearing portion 7B of the lower bearing 7 for forming a discharge flow passage 200 for allowing the refrigerant to flow out of the muffler 20.

Hereinafter, the configuration of the

discharge flow channels

100 and 200 will be described.
FIG. 3 shows a discharge flow passage 100 formed with a predetermined flow passage length x ₀ between the bearing portion 6B of the upper bearing 6 positioned around the axis of the rotary shaft 3 and the flow passage wall 12 of the upper muffler 10. It shows.
The dimension of the discharge flow passage 100 in the radial direction of the rotation shaft 3 changes in the circumferential direction D1 of the rotation shaft 3.
The flow path length x ₀ (FIG. 2B) of the discharge flow path 100 is the same over the entire circumference.
The cross-sectional area of the entire discharge flow channel 100, that is, the area of the discharge flow channel 100 projected in the axial direction of the rotary shaft 3 is determined in consideration of both the performance of the compressor 1 and the pulsation reduction effect by the muffler 10. ing.

Although the plan view of the discharge flow channel 200 is omitted regarding the lower muffler 20, the discharge flow channel 200 can be configured similarly to the discharge flow channel 100.

Hereinafter, the configuration of the discharge flow path 100 will be described in detail.
The discharge flow passage 100 has a first flow passage portion 101 located in a part of the circumferential direction D1 of the rotation shaft 3 and a second flow passage portion 102 adjacent to the first flow passage portion 101 in the circumferential direction D1. The cross-sectional area of the second flow passage portion 102 is relatively large between both the first flow passage portion 101 and the second flow passage portion 102.

The compressed refrigerant that has been compressed and discharged into the muffler 10 flows through the first flow passage portion 101 and the second flow passage portion 102 and flows out of the muffler 10 with pulsation. The pressure fluctuation of the refrigerant flowing out of the first flow passage portion 101 and the pressure fluctuation of the refrigerant flowing out of the second flow passage portion 102 interfere with each other and are reduced.

The discharge flow channel 100 preferably includes a plurality of first flow channel portions 101 and a plurality of second flow channel portions 102. The discharge flow channel 100 of the present embodiment has three first flow channel portions 101 and three second flow channel portions 102.
The discharge flow path 100 is formed over the entire circumference around the axis of the rotation shaft 3, and the first flow path portion 101 and the second flow path portion 102 are alternately arranged in the circumferential direction D 1 of the rotation axis 3. Preferably, they are arranged alternately.
It is preferable that the second flow passage portions 102 be arranged substantially equally in the circumferential direction D1.

The flow path wall 12 forms a second flow path portion 102 between the first wall portion 121 forming the first flow path portion 101 between the outer peripheral portion of the bearing portion 6B and the outer peripheral portion of the bearing portion 6B. And a second wall 122. The first wall portion 121 is present in the same number as the first flow path portion 101, and the second wall portion 122 is present in the same number as the second flow path portion 102.

The first flow passage portion 101 is formed in a circular arc shape in cross section concentric with the rotation shaft 3 and the bearing portion 6B. The same is true for the first wall 121.
The first wall 121 is disposed along the outer peripheral surface (cylindrical surface) of the bearing 6B at a predetermined distance from the outer peripheral surface. The distance between the first wall portion 121 and the outer peripheral surface of the bearing portion 6B, that is, the width of the first flow passage portion 101 is, for example, less than 1 mm.

The second flow passage portion 102 is shaped so as to expand radially outward with respect to the outer peripheral surface of the bearing portion 6B. The same applies to the second wall 122.
The dimension of the second flow passage portion 102 in the radial direction of the rotation shaft 3 is larger than that of the first flow passage portion 101.
The cross-sectional shape of the second wall 122 corresponding to the second flow passage 102 can be appropriately determined, for example, C-shaped (or U-shaped), V-shaped, or the like. In the second wall 122, the end 122A of the second wall 122 connected to the first wall 121 passes the most expanded top 122B so that the flow path loss of the flow passing through the second flow path 102 is reduced. It is preferable to form a smooth shape up to the other end 122C.
As an example, the second wall portions 122 in the present embodiment are each formed in a substantially C-shaped cross section symmetrically with respect to the center line CL passing through the center in the circumferential direction D1. The second wall 122 may be formed in a substantially V shape so as to extend from the top 122B to both sides in the circumferential direction D1.

The cross-sectional shapes of the first flow passage portion 101 and the second flow passage portion 102 are constant in the axial direction of the rotation shaft 3 orthogonal to the paper surface of FIG. 3, but is not limited thereto.

The discharge flow path 100 is divided into a narrow first flow path portion 101 and a second flow path portion 102 in which the width of the flow path is enlarged with respect to the first flow path portion 101 in the circumferential direction D1. There is. A boundary line (for example, L1 and L2) is drawn between the first flow passage portion 101 and the second flow passage portion 102 along the radial direction of the rotary shaft 3, and the first flow is performed at the boundary line. The cross-sectional area of each of the passage portion 101 and the second flow passage portion 102 can be assumed.
The cross-sectional area of the first flow passage portion 101 is smaller than the cross-sectional area of the second flow passage portion 102. Therefore, the flow velocity of the refrigerant flowing through the first flow passage portion 101 is faster than the flow velocity of the refrigerant flowing through the second flow passage portion 102.

FIG. 4 shows the pulsation (a) of the refrigerant flowing into the first flow passage portion 101 from the inside of the muffler main body 11 and the pulsation (b) of the refrigerant flowing into the second flow passage portion 102 from the inside of the muffler main body 11. And respectively. Here, the horizontal axis indicates the distance x in the longitudinal direction of the flow path.
Since the first flow path portion 101 at a flow rate of a relatively small cross-sectional area is high, the waveform of the pressure fluctuation p ₁ of the first flow path portion 101 shown in FIG. 4 (a), second shown in FIG. 4 (b) compared with waveforms of pressure fluctuations p ₂ of the flow path portion 102, it is stretched in the horizontal axis (x) direction.

The refrigerant injected into the muffler main body 11 flows into the first and second

flow path portions

101 and 102, respectively, and flows from the beginning (x = 0) of the first and second

flow path portions

101 and 102 to a predetermined flow. pathlength _{x 0} the first flow at a speed corresponding to the cross-sectional area of each of the

second channel portion

101 and 102, the housing 5 in a first, terminal end of the second flow path 101 and 102 (x = _{x 0)} It leaks into the inside.

The refrigerant in the muffler main body 11 can be considered to flow into the beginning (x = 0) of each of the first and second

flow path portions

101 and 102 in the same phase, and the first and second flows The amplitudes of the pressure fluctuations p ₁ and p ₂ of the refrigerant flowing through the

passage portions

101 and 102 can be regarded as the same.
The wave numbers of pressure fluctuations p ₁ and p ₂ from the start end (x = 0) to the end (x = x ₀ ) differ depending on the difference in the flow velocity of the refrigerant flowing through the first and second

flow path portions

101 and 102 respectively. As a result, the phase that was the same when flowing into the first and second

flow path portions

101 and 102 is shifted at the end (x = x ₀ ) of the first and second

flow path portions

101 and 102.
Therefore, the pressure waves of the refrigerant flowing out of the first and second

flow path portions

101 and 102 interfere with each other and attenuate, whereby the outflow of the pressure fluctuation to the outside of the muffler 10 is sufficiently suppressed. The phases of the pressure waveform differ by 180 ° (π) at the ends (x = x ₀ ) of the first and second

flow path portions

101 and 102 so that the pressure waves sufficiently cancel each other due to interference, that is, they are opposite phases. Is preferred.
The wave numbers of the pressure fluctuations p ₁ and p ₂ shown in FIG. 4 are an example.

As described above, in the present embodiment, as shown in the following equation (I), the pressure waves become opposite in phase with each other at the end of the first and second

flow path portions

101 and 102 and cancel each other. depending on the frequency f, it sets the channel length _{x 0,} and a first, a flow rate ratio of the

second channel portion

101 and 102 alpha.

α = n (v ₁ / 2fx ₀ ) +1 (I)
n is a natural number (1, 2, 3 ...)
Here, the flow velocity ratio α is a flow velocity based on relatively fast v ₁ among the flow velocity v _{1 of the} refrigerant flowing in the first flow passage portion 101 and the flow velocity v ₂ of the refrigerant flowing in the second flow passage portion 102 It is a ratio (v ₂ / v ₁ ).

An equation equivalent to equation (I) can also be set by the flow velocity ratio 1 / α based on the flow velocity of the second flow passage 102. It is also permissible to design the first and second

flow path portions

101 and 102 using the equation.

Hereinafter, the process for obtaining the above formula (I) will be described.
Under the conditions that the phases when flowing into the first and second

flow path portions

101 and 102 are the same and the amplitudes are the same, the waves of the pressure fluctuations p ₁ and p ₂ are represented by equation (i). t represents time, P represents the pressure wave amplitude, k ₁ and k ₂ represent the wave number, and ω represents the angular frequency. The pressure fluctuations p ₁ and p ₂ differ only in the wavenumbers k ₁ and k ₂ .
p ₁ (x, t) = P sin (k ₁ x-ωt)
p ₂ (x, t) = P sin (k ₂ x-ωt) (i)

Here, when the flow velocity of the refrigerant in the first flow passage portion 101 is v ₁ and the flow velocity of the refrigerant in the second flow passage portion 102 is v ₂ ,
v ₁ = ω / k ₁ v ₂ = ω / k ₂ (ii)
Assuming that the flow velocity ratio based on v ₁ which is relatively faster among v ₁ and v ₂ is α,
v ₁ = αv ₂ (α> 1)
From equation (ii),
k ₂ = α k ₁ (iii)

The pressure fluctuation p (x = x ₀ , t) synthesized at the time of merging from the end of the first and second

flow path portions

101 and 102 is solved. Reference is made to formula (iii).
p (x = x ₀ , t)
= P ₁ + p ₂ = P sin (k ₁ x _0- ωt) + P sin (k ₂ x _0- ωt)
= 2 P sin {(1 + α / 2) k ₁ x _0- ω t} cos {(1-α / 2) k ₁ x ₀ } (iv)

From equation (iv), if the term of cos {(1−α / 2) k ₁ x ₀ } is 0, the pressure waves cancel each other due to interference (synthesis).
Because a wave of y = cos θ is 0 when θ = n (π / 2) (n = 1, 2, 3 ...),

At this time, p (x ₀ , t) becomes zero.
Here, the smaller the value of α, the easier it is to realize the discharge flow path. Then, considering that the pulsation reduction by the minimum α is to be realized, since n = 1,

From equations (v '), (ii) and ω = 2πf,

Equation (I ') is obtained by modifying this equation.
α = (v ₁ / 2fx ₀ ) +1 (I ')
Formula (I ') is a case where n = 1 in the above-mentioned formula (I).
Equations (I) and (I ′) show the relationship between x ₀ and α, in which the pressure waves cancel each other.

An example of designing the flow velocity ratio α (v ₂ / v ₁ ) using the formula (I ′) is shown.
Here, the range of the frequency f is approximately 50 Hz to 1 kHz (1000 Hz), and the frequency of the pressure fluctuation component that needs to be reduced is selected.
For example, x ₀ can be set to about 10 mm (0.01 m).
For example, v ₁ is 0.1 m / s to 200 m / s from the volume velocity obtained from the displacement amount and rotation speed of the compression mechanism 41 and the entire cross-sectional area of the discharge flow path 100.

The values of the above parameters are applied to equation (I ').
From the condition of the above values, if f = 1000 Hz and v ₁ = 0.1 m / s are applied as if α is minimized, then 5 × 10 ⁻¹ +1 is obtained and if α is maximized, f Applying = 500 Hz and v ₁ = 200 m / s yields 20 + 1.

By selecting an appropriate flow velocity ratio α in accordance with the frequency f of the pressure fluctuation component that needs to be reduced, the pressure waves that flow out from the first and second

flow path portions

101 and 102 and are merged cancel each other. As a result, the pressure fluctuation flowing out of the muffler 10 can be reduced. Accordingly, the occurrence of resonance in the space below the motor 2 can be avoided, and noise can be suppressed.
The cross-sectional area of each of the first and second

flow channel portions

101 and 102 can be derived from the selected flow velocity ratio α and the cross-sectional area of the entire discharge flow channel 100. Then, the muffler 10 may be shaped so as to give an appropriate cross-sectional area between the bearing 6B and the first wall 121 and between the bearing 6B and the second wall 122, respectively.

Although the discharge flow channel 100 of the upper muffler 10 has been described above as an example, the flow velocity ratio α is derived for the discharge flow channel 200 of the lower muffler 20 using the same formula (I) or formula (I ′) The muffler 20 may be shaped such that a suitable cross-sectional area is given to the first flow passage portion 101 and the second flow passage portion 102, respectively.

As described above, when canceling pressure waves whose phases are shifted by flowing through the first and second

flow path portions

101 and 102 at the time of merging, the first flow path portion 101 and the second flow path portion 102 It is preferable that the refrigerant streams flowing out from the ends of the first and second

flow path portions

101 and 102 join immediately after the outflow and the respective pressure waves interfere with each other.
In this respect, in the present embodiment, as shown in FIG. 3, the plurality of first flow path portions 101 and the plurality of second flow path portions 102 exist in the discharge flow path 100, and further, the first, Advantageously, the second

flow path portions

101 and 102 are alternately arranged over the entire circumference of the rotation shaft 3. That is, the places where the first flow path unit 101 and the second flow path unit 102 are adjacent to each other in the circumferential direction D1 are distributed over the entire circumference of the rotation shaft 3 and any one of them is adjacent to each other. 1. Since the pressure waves interfere immediately after the outflow of the refrigerant flow that has flowed out of the first and second

flow path portions

101 and 102, the pulsation is efficiently reduced.

If it is assumed that only one second flow path portion 102 (for example, 102A) exists in the discharge flow path 100 and the rest of the discharge flow path 100 is the first flow path portion 101, the pulsation reduction effect is achieved. Can be obtained at locations on both sides of the single second flow passage portion 102.
That is, as in the present embodiment, the portions where the first flow passage portion 101 and the second flow passage portion 102 are adjacent are distributed in the circumferential direction D1 of the rotation shaft 3, so that a wide range in the circumferential direction D1 is obtained. As pressure waves interfere with each other, pulsation can be efficiently reduced.

In the present embodiment, the

discharge flow paths

100 and 200 including the first and second flow path portions having different cross-sectional areas are respectively set for both the

mufflers

10 and 20. The pulsations propagating to it can be reduced more sufficiently.
However, the discharge flow path including the first and second flow path portions is set only for one of the

mufflers

10 and 20, and the other discharge flow path has, for example, an annular shape around the axis of the rotation shaft 3. It is also acceptable to be formed in

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG.
In the following, matters different from the first embodiment will be mainly described. The same components as those of the first embodiment are denoted by the same reference numerals.

The discharge flow path 300 formed between the muffler 30 and the bearing portion 6B according to the second embodiment includes a plurality of second

flow path portions

302A, 302B, and 302C, as shown in FIG.
The muffler 30 can be applied to any of the muffler (10 in FIG. 1) constituting the upper compression mechanism 41 and the muffler (20 in FIG. 1) constituting the lower compression mechanism 42 (FIG. 1).

The second

flow path portions

302A, 302B, and 302C have different cross-sectional areas. The cross-sectional area of each of the second

flow path portions

302A, 302B, 302C is determined in consideration of the frequency of the pulsation component that needs to be reduced.
For example, the second flow passage portion 302A corresponds to 800 Hz, the second flow passage portion 302B corresponds to 900 Hz, and the third flow passage portion 302C corresponds to 1 kHz.
The cross-sectional area of any of the second flow channel portions 302A to 302C is set by deriving the flow velocity ratio α with the adjacent first flow channel portion 101 using the above-mentioned equation (I) or (I ′) There is.

According to the second embodiment, it is possible to cope with pulsation in a wide frequency range compared to the first embodiment.
In the discharge flow path 300, the second flow path portions 302A to 302C are alternately arranged with the first flow path portion 101 in the circumferential direction D1 of the rotary shaft 3, so the first flow path portion 101 and the second flow path The pulsation can be efficiently reduced at each of the places where the portions 302A to 302C are adjacent to each other.

FIG. 6 shows a muffler 50 according to a variant of the invention.
The discharge flow path 500 formed between the muffler 50 and the bearing portion 6B is formed in a petal shape including a large number of flow path portions as compared with the first embodiment and the second embodiment. Here, eight first flow path portions 501 having an arc-shaped cross section and eight second flow path portions 502 are included in the discharge flow path 500.
The muffler 50 is applicable to any of the muffler (10 in FIG. 1) constituting the upper compression mechanism 41 and the muffler (20 in FIG. 1) constituting the lower compression mechanism 42.

The cross-sectional areas of the first flow passage portion 501 and the second flow passage portion 502 can be respectively determined using the above-described formulas (I) and (I ').

Since the number of first flow path portions 501 and the number of second flow path portions 502 are large, the number of portions where the first flow path portion 501 and the second flow path portion 502 are adjacent in the circumferential direction D1 is also large. Therefore, according to the present embodiment, it is possible to efficiently reduce the pulsation due to the interference of the pressure waves of the refrigerant flowing out and joining the first and second

flow path portions

501 and 502, respectively.

In this example, there are two types of second flow path portions 502 (A) and 502 (B) having different cross-sectional areas. The cross-sectional area of these 2nd flow-path part 502 (A), 502 (B) can each be defined by Formula (I), (I ') mentioned above corresponding to a different frequency.

FIG. 7 shows a muffler 60 according to another variant of the invention.
The muffler 60 includes a muffler main body 11 and a cylindrical flow path wall 62 concentric with the rotation shaft 3. A plurality of grooves 6 </ b> C extending in the axial direction are formed to be recessed in the outer peripheral portion of the bearing portion 6 </ b> B. Due to the presence of these grooves 6C, the discharge flow passage 600 between the bearing portion 6B and the flow passage wall 62 has a relatively large cross-sectional area with the plurality of first flow passage portions 601 having a relatively small cross-sectional area. A plurality of second flow path portions 602 are provided.
The cross-sectional areas of the first flow passage portion 601 and the second flow passage portion 602 can be respectively determined using the above-described formulas (I) and (I ').
By changing the depths and widths of the plurality of grooves 6C, the cross-sectional areas of the plurality of second flow path portions 602 can be made different from one another to cope with pulsation components of a plurality of frequencies.

FIG. 8 shows a muffler 70 according to yet another variant of the invention.
The muffler 70 includes a muffler main body 11, a substantially cylindrical flow path wall 72 concentric with the rotation shaft 3, and a discharge flow path 700 between the flow path wall 72 and the bearing portion 6B. The flow path wall 72 has a protruding portion 721 protruding radially outward in a part of the circumferential direction, and an arc portion 722 which is a portion other than the protruding portion 721. A plurality of protrusions 721 and a plurality of arcs 722 are alternately arranged in the circumferential direction of the flow path wall 72.
The first flow path portion 701 of the discharge flow path 700 exists inside the projecting portion 721 which is formed so as to be folded back in a state in which the

walls

721A and 721B facing each other are close to each other.
The second flow passage portion 702 of the discharge flow passage 700 is present between the inner circumferential portion of the arc portion 722 and the outer circumferential portion of the bearing portion 6B.
Since the distance between the arc portion 722 and the bearing portion 6B is wider than the distance between the first wall portion 121 and the bearing portion 6B in the first embodiment, the cross-sectional area of the second flow path portion 702 is And the cross-sectional area of the first channel portion 701.
By respectively determining the cross-sectional areas of the first flow channel portion 701 and the second flow channel portion 702 using the formulas (I) and (I ') described above, the flow out from the first and second

flow channel portions

701 and 702 respectively The pulsations can be efficiently reduced by the interference of the pressure waves of the joining refrigerant.
The cross-sectional areas of the plurality of second flow path portions 702 are made different from each other by changing the protruding lengths of the plurality of protruding portions 721 and the distance between the

walls

721A and 721B, and the pulsating components of the plurality of frequencies are handled. can do.

In addition to the above, the configurations described in the above embodiment can be selected or changed to other configurations as appropriate without departing from the spirit of the present invention.

The first flow passage portion of the discharge flow passage in the present invention does not necessarily have to be formed in an arc shape concentric with the rotation shaft 3. In addition, the cross-sectional area may be different among the plurality of first flow path portions. It is sufficient for the first flow passage portion to form a narrow gap with the rotation shaft 3 or the bearing portion 6B as compared to the second flow passage portion.
Moreover, in the circumferential direction D1 of the rotating shaft 3, it is not necessary to necessarily arrange the first flow passage portion and the second flow passage portion alternately. For example, in the configuration shown in FIG. 6, it is also allowed that a second flow passage portion 502B having a cross-sectional area different from that of the second flow passage portion 502A is located next to the second flow passage portion 502A.
In addition, the cross-sectional area and arrangement of each of the first flow path portion and the second flow path portion of the discharge flow path are the frequency f to be reduced, the flow path length x ₀ , the performance of the compressor, and the pulsation reduction effect Accordingly, it can be set appropriately using formulas (I) and (I ').

The discharge flow path in the present invention does not necessarily have to be continuous over the entire circumference of the rotation shaft 3 in the circumferential direction D1. The flow passage wall 12 of the muffler may be in contact with the outer peripheral portion of the bearing portion 6B in a part of the circumferential direction D1.
Moreover, a partition may be arrange | positioned in the boundary of a 1st flow-path part and a 2nd flow-path part. In this case, the first flow passage portion and the second flow passage portion are adjacent to each other via the partition. Also in this case, the cross-sectional area of each of the first and second flow path sections divided by the partition can be determined using the formulas (I) and (I ').
In particular, in the case where the number of second flow path portions is large as in the configuration shown in FIG.

The compression mechanism mounted on the compressor of the present invention is not limited to the twin rotary compression mechanism 4 but may be a single rotary compression mechanism having a pair of cylinders and piston rotors and a muffler.
Moreover, as a power source of the compressor of the present invention, for example, an engine or the like other than a motor is acceptable.

DESCRIPTION OF SYMBOLS 1 compressor 2 motor 2A stator 2B rotor 2C coil 3 rotating shaft 3A spindle part 3B upper crank pin 3C lower crank pin 4 compression mechanism 4A partition plate 5 housing 5A discharge pipe 6 upper bearing

6A abutment part

6B bearing part 6C groove 7 lower part Bearing

7A Abutment portion

7B Bearing portion

8, 9 Piping 10 Upper muffler 10A Opening 11 Muffler main body 11B Bolt 12 Flow path wall 20 Lower muffler 21 Muffler main body 22 Flow path wall 30

Muffler

302A, 302B, 302C Second flow path portion 41 Upper part Compression mechanism 42 Lower compression mechanism 50 muffler 501 first flow passage portion 502, 502A, 502B second flow passage portion 60 muffler 62 flow passage wall 70 muffler 72 flow passage wall 100 discharge flow passage 101 first flow passage portion 102 second flow Road portion 111 Inner circumferential end 112 Curved portion 121 first wall 122 second wall 122A one end 122B top 122C other end 200 discharge passage 411 upper piston rotor 412 upper cylinder 421 lower piston rotor 422 lower cylinder 500 discharge passage 600 discharge passage 601 first passage portion 602 Second flow path portion 700 Discharge flow path 701 First flow path portion 702 Second flow path portion 721 Protrusive portion 722 Arc portion D1 Circumferential direction of rotation shaft

Claims

A rotating shaft that is rotated,
A rotary type compression mechanism having a piston rotor provided on the rotary shaft and a cylinder on which the piston rotor is disposed;
And a muffler disposed around the axis of the rotation axis,
The muffler is
A muffler body for receiving the fluid compressed by the compression mechanism inside;
Between the rotary shaft or a bearing portion positioned around the rotary shaft, a discharge flow passage of a predetermined length is formed to allow the fluid to flow out of the muffler along the axial direction of the rotary shaft. A flow passage wall, and
The discharge channel is
A first flow passage portion positioned in a part of a circumferential direction of the rotation shaft;
A second flow adjacent to the first flow passage in the circumferential direction and having a dimension in the radial direction of the rotation axis larger than that of the first flow passage and larger in cross-sectional area than the first flow passage And a road section,
A rotary compressor characterized by
The discharge flow path includes a plurality of the second flow path portions.
The rotary compressor according to claim 1, characterized in that:
The cross-sectional area of each of the plurality of second flow path portions is different from each other,
The rotary compressor according to claim 2, characterized in that:
The discharge channel is
It is formed over the entire circumference around the axis of the rotation axis,
The plurality of first flow path portions and the plurality of second flow path portions alternately arranged in the circumferential direction
The rotary compressor according to claim 2, characterized in that:
The discharge channel is
It is formed over the entire circumference around the axis of the rotation axis,
The plurality of first flow path portions and the plurality of second flow path portions alternately arranged in the circumferential direction
The rotary compressor according to claim 3, characterized in that:
The portion of the flow path wall that forms the second flow path portion is formed to have a substantially C-shaped cross section or a substantially V-shaped cross section.
The rotary compressor according to any one of claims 1 to 5, characterized in that.
A rotating shaft that is rotated,
A rotary type compression mechanism having a piston rotor provided on the rotary shaft and a cylinder on which the piston rotor is disposed;
And a muffler disposed around the axis of the rotation axis,
The muffler is
A muffler body for receiving the fluid compressed by the compression mechanism inside;
Between the rotary shaft or a bearing portion positioned around the rotary shaft, a discharge flow passage of a predetermined length is formed to allow the fluid to flow out of the muffler along the axial direction of the rotary shaft. A flow passage wall, and
The discharge channel is
A first flow passage portion positioned in a part of a circumferential direction of the rotation shaft;
And a second flow passage portion having a cross-sectional area larger than that of the first flow passage portion,
The first channel portion protrudes radially outward from the second channel portion.
A rotary compressor characterized by
The length of the discharge channel is x 0 ,
The flow velocity of the fluid in the first channel portion is v 1 ,
The flow velocity ratio of the flow velocity of the fluid in the second flow passage to v 1 is α,
If you set the predetermined frequency f,
Assuming that n is a natural number,
α = n (v 1 / 2fx 0 ) +1
Is established,
The rotary compressor according to any one of claims 1 to 5, 7 characterized in that.
The length of the discharge channel is x 0 ,
The flow velocity of the fluid in the first channel portion is v 1 ,
The flow velocity ratio of the flow velocity of the fluid in the second flow passage to v 1 is α,
If you set the predetermined frequency f,
Assuming that n is a natural number,
α = n (v 1 / 2fx 0 ) +1
Is established,
The rotary compressor according to claim 6, characterized in that:
Pressure fluctuations of the fluid respectively flowing out from the first flow path portion and the second flow path portion interfere and cancel each other,
The rotary compressor according to any one of claims 1 to 5, 7 characterized in that.
Pressure fluctuations of the fluid respectively flowing out from the first flow path portion and the second flow path portion interfere and cancel each other,
The rotary compressor according to claim 6, characterized in that:
Pressure fluctuations of the fluid respectively flowing out from the first flow path portion and the second flow path portion interfere and cancel each other,
The rotary compressor according to claim 9, characterized in that: