JPH04342896A - Two cylinder type rotary compressor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary compressor equipped with two cylinders, and more particularly to an improved return gas passage structure for guiding compressed gas from a sub-valve cover to a main valve cover.

0002

2. Description of the Related Art There is a tendency for two-cylinder rotary compressors to be frequently used in, for example, refrigeration cycle equipment. The two-cylinder rotary compressor is generally configured as shown in FIG. 4.

In the figure, reference numeral 1 denotes a closed case, and an electric compressor main body 2 is accommodated within this closed case 1. The electric compressor main body 2 has an upper electric motor section 3 and a lower compression mechanism section 4 connected via a rotating shaft 5.

The compression mechanism section 4 includes a first cylinder 6 and a second cylinder 7 in the vertical direction, and these cylinders 6
, 7 is provided with an intermediate partition plate/frame 8. The rotating shaft 5 has a main bearing 9 provided in the first cylinder 6 at its substantially central portion, and a sub-bearing 10 provided in the second cylinder 7 at its lower end.
It is rotatably supported.

[0005]The first cylinder 6 of the rotating shaft 5
Eccentric crank portions 11 and 12 are provided at portions corresponding to the inner and second cylinders 7 that are 180° out of phase with each other.

A first roller 13 and a second roller 14 are fitted onto the circumferential surfaces of these eccentric crank parts 11 and 12, and are accommodated in the respective cylinders 6 and 7 so as to be eccentrically rotatable. .

The main bearing 9 is provided with a first discharge port 15 that communicates with the inside of the first cylinder 6 and is operated to open and close. A main valve cover 16 is provided.

The main valve cover 16 has an outer peripheral end having the same shape as the outer peripheral end of the main bearing 9, and an inner peripheral end thereof in contact with the pivot portion of the rotating shaft 5 of the main bearing 9. A gas discharge port 17 is provided at a predetermined position on the inner peripheral end, and communicates the inside of the main valve cover 16 with the inside of the sealed case 1. The secondary bearing 10 is provided with a second discharge port 18, and further provided with a secondary valve cover 19 that surrounds the second discharge port 18 via an internal cavity.

The auxiliary valve cover 19 has an outer peripheral end having substantially the same shape as the outer periphery of the auxiliary bearing 10, and covers the rotating shaft 5 and the lower end of the auxiliary bearing 10 with its end surface. That is, the second discharge port 18 is airtightly covered with an internal cavity.

A return gas passage 20 is provided that integrally passes through the first and second cylinders 6, 7, the intermediate partition plate/frame 8, and the main and sub bearings 9, 10. That is, this return gas passage 20 is provided in a straight line in the vertical direction, its upper end opening communicates with the internal cavity of the main valve cover 16, and its lower end opening communicates with the sub valve cover 19.
communicates with the internal cavity of.

On the other hand, only the suction pipe 21 connected to the second cylinder 7 is shown here, and the suction pipe 21 passes through the sealed case 1 and communicates with an evaporator (not shown) via a suction cup 22 on the outside. be done. The first cylinder 6 is also provided with a suction pipe of exactly the same construction and communicates with the evaporator via another suction cup. On the other hand, a discharge pipe 23 is connected to the upper end of the sealed case 1, and communicates the inside of the sealed case 1 with a condenser (not shown).

[0012] As the rotating shaft 5 rotates,
Each eccentric crank part 11, 12 performs an eccentric rotation movement together with rollers 13, 14 fitted therein, and the refrigerant evaporated in the evaporator is transferred from each suction cup 22 through a suction pipe 21 into each cylinder 6, 7. Inhale.

In each cylinder 6, 7, the sucked gas is compressed, and the gas compressed in the first cylinder 6 on the upper side is sent from the first discharge port 15 to the main valve cover 1.
It is discharged within 6 minutes. The gas compressed in the second cylinder 7 on the lower side is discharged from the second discharge port 18 into the sub-valve cover 19 .

The gas inside the sub-valve cover 19 is
All are led to the return gas passage 20, and the main valve cover 1
After being mixed with the gas in the gas in the airtight case 1 , they are both released from the gas outlet 17 into the sealed case 1 . The sealed case 1 is filled with compressed and highly pressurized gas, which is led out to the condenser from a discharge pipe 23 provided at the top.

[0015]

[Problem to be solved by the invention] In this way, the second
The gas compressed in the cylinder 7 and discharged into the sub valve cover 19 is guided into the main valve cover 16 via the return gas passage 20.
0 is merely provided so that the main bearing 9 and the sub-bearing 10 communicate with each other over the shortest distance.

On the other hand, the timing at which gas is discharged from each cylinder 6, 7 into the opposing valve covers 16, 19 is somewhat intermittent even in a rotary compressor. This allows each valve cover 1
It is inevitable that pressure pulsations occur in the internal cavities of 6,19.

Since the internal cavities of the valve covers 16 and 19 are communicated with each other through a return gas passage 20 provided as appropriate, the pressure pulsations generated in the internal cavity of the main valve cover 16 and the sub-valve cover 19 are separated. The disadvantage is that the pressure pulsations generated in the internal cavity tend to interfere with each other, and the operation noise caused by these pressure pulsations of the discharged gas is large.

The present invention has been made in view of the above-mentioned circumstances, and its object is to control the overall length of the return gas passage and the relative positions of the openings of the main bearing and the sub-bearing of the return gas passage by adjusting the pressure. By taking into account conditions such as the wavelength of the pulsating standing wave, the same wavelength constant, and the average propagation path length from each discharge port to the opening of the return gas passage, and setting it after logically calculating it, each valve It is an object of the present invention to provide a two-cylinder rotary compressor that can offset pressure pulsations generated in the internal cavity of a cover and reliably reduce operating noise.

[0019]

[Means for Solving the Problems] In order to achieve the above object, the present invention houses an electric motor section and a compression mechanism section connected via a rotating shaft in a sealed case, the compression mechanism section being , a pair of eccentric crank parts whose maximum eccentric positions have a phase difference of 180° from each other are provided on the rotating shaft, and a first cylinder and a second cylinder each accommodate the eccentric crank parts so as to freely rotate eccentrically, The first cylinder is provided with a main bearing that rotatably supports the middle part of the rotating shaft, and the main bearing once receives the gas compressed in the first cylinder and discharged from the first discharge port. A main valve cover is provided to guide the discharge from the inside of the sealed case, and the second cylinder is provided with a sub-bearing that rotatably supports the end of the rotating shaft. A sub-valve cover is provided which temporarily receives gas discharged from the second discharge port, and guides the gas received by the sub-valve cover across the sub-bearing, the pair of cylinders and the main bearing, and guides the gas into the main valve cover. A return gas passage leading to is provided, and the total length L of the return gas passage is:

[0020]

[Equation 3], and the relative positions of the return gas passage openings provided in the main bearing and the sub-bearing are:

[0021]

A two-cylinder rotary compressor characterized by being set to have the following relationship: [Equation 4]. (However, xb: Length along the average propagation path from the second discharge port xa: Length along the average propagation path from the first discharge port γ=Xb/Xa Xb: Average propagation path in the sub-valve cover (Xa: Length of one circumference of the average propagation path inside the main valve cover.)
It is.

[0022]

[Operation] By setting the overall length of the return gas passage and the relative positions of the turn gas passage openings in the main bearing and the sub-bearing as shown in the above equation, pressure pulsations occurring in the internal cavities of the main and sub-valve covers can be reduced. canceled out.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The overall configuration of the two-cylinder rotary compressor is as described above with reference to FIG. 4, and further explanation will be omitted. 1 to 3 show the main parts of the compression mechanism section 4. Since the other components are the same as those explained earlier, except for the return gas passage 30, which will be described later, the same numbers are attached to the new components. Further explanations will be omitted.

The return gas passage 30 connects the main bearing 9, the first cylinder 6, and the partition plate/frame so that the opening A provided in the main bearing 9 and the opening B provided in the sub bearing 10 communicate with each other. 8. Second cylinder 7 and secondary bearing 10
It passes through.

To explain, the main bearing 9 and the sub bearing 1
0, the openings A and B are provided so as to penetrate in parallel to the axial direction of the rotating shaft 5, that is, in the vertical direction. The mating surface between the main bearing 9 and the first cylinder 6 and the sub-bearing 10
The mating surfaces of the cylinder 7 and the second cylinder 7 are provided with grooves each having a semicircular cross section, so that the combined surfaces have a circular cross section, and are formed into an arc shape with a predetermined radius of curvature. The distal end portions thereof are provided so as to extend vertically through the first cylinder 6, the partition plate/frame 8, and the second cylinder 7. The total length L of the return gas passage 30 between the opening A of the main bearing 9 and the opening B of the sub-bearing 10 is as follows:

[0027]

It is set to [Equation 5]. However, γ=Xb/Xa

The average propagation path R is defined as follows. FIG. 2 illustrates the average propagation path R within the sub-valve cover 19. That is, the angle line S extends at a certain angle from the axis of the rotating shaft 5. On this angle line S, a midpoint m is taken between the inner surface of the circumferential wall of the sub-valve cover 19 and the circumferential surface of the rotating shaft pivot portion 10a of the sub-bearing 10. The angle line S is extended over an angle of 0° to 360°, and the intermediate point on each angle line S between the inner surface of the circumferential wall of the sub-valve cover 19 and the circumferential surface of the rotation shaft pivot portion 10a of the sub-bearing 10 Take m. A broken line connecting all intermediate points m becomes an average propagation path R within the sub-valve cover 19.

Note that the average propagation path R within the main valve cover 16 is similarly obtained by connecting the intermediate point between the inner surface of the peripheral wall of the main valve cover 16 and the peripheral surface of the rotating shaft pivot portion of the main bearing 9. .

Next, the relative positional relationship between the opening A and the opening B in the return gas passage 30 will be explained with reference to FIG. That is, the starting point is the intersection of the line connecting the axis of the rotating shaft 5 and the first discharge port 15 provided in the main bearing 9 and the above-mentioned average propagation path R (not particularly shown here) within the main valve cover 16. Then, the length taken along the average propagation path R and in the rotational direction of the rotation shaft 5 up to the intersection of the line connecting the axis of the rotation shaft 5 and the opening A and the above average propagation path R is xa shall be.

On the other hand, the rotation begins at the intersection of the line connecting the axis of the rotating shaft 5 and the second discharge port 18 provided on the sub-bearing 10 side and the average propagation path R in the sub-valve cover 19. When xb is the length taken along the average propagation path R in the rotational direction of the rotating shaft 5 up to the intersection of the line connecting the axis of the shaft 5 and the opening B and the average propagation path R, The relative position of the above xa and xb is

[0032]

[Math 6] It is set so that

By the way, the pressure pulsations at the opening B of the return gas passage 30 are caused by a component of the pressure pulsations accompanying the compression action in the first cylinder 6, a propagation component via the return gas passage 30, and a component of the pressure pulsations at the opening B of the return gas passage 30. This is the sum of the pressure pulsation components that occur due to the compression action within 7. and,
If this sum is 0, no pressure pulsation will occur as a result, and a reduction in operating noise can be achieved. Expressing this numerically, it is as follows. A0 cos(kb・xb) sin(
ωt−π) + A0 co
s(ka・xa+ka・L) sinωt
= 0

...(1) must be satisfied. In addition, A0 cos(kb・xb) sin(ωt−π)
: Pressure pulsation A0 within the sub-valve cover 19 itself cos(ka・xa+ka・L) sinωt: Pressure pulsation propagation from within the main valve cover 16 A0: Size of pressure pulsation kb: Pressure pulsation constant within the sub-valve cover 19 Wavelength constant of existing waves (=2π/λb) xb: Length along average propagation path R between second discharge port 18 and opening B λb: Wavelength of pressure pulsating standing waves in sub-valve cover 19 ω: Angular frequency (=2πf) f: Frequency t: Time π: Crank phase difference angle ka: Wavelength constant of pressure pulsating standing wave in main valve cover 16 (=2π/λa) xa: First discharge Length λa along the average propagation path R between port 15 and opening A: Wavelength L of the pressure pulsating standing wave in main valve cover 16: Return gas passage leading between opening A and opening B Total length of 30 Expanding the above equation (1), cos (kb xb) sin
ωt = co
s(ka・xa+ka・L) sinωt, therefore, ka・xa+ka・L =
kb・xb+2nπ...(2)

(n=0.±1,±2,±3...
)

On the other hand, the opening A of the return gas passage 30
The pressure pulsations caused by the compression action in the second cylinder 7 are the sum of the propagation component via the return gas passage 30 and the pressure pulsation component caused by the compression action in the first cylinder 6. become. And this sum is 0
If so, as a result, no pressure pulsation will occur,
Operation noise can be reduced. Expressing this numerically, it is as follows. A0 cos(ka・xa)sinωt
+ A0 cos(kb・x
b+kb・L) sin(ωt−π)
= 0

...(3) must be satisfied. Note that A0 cos(ka・xa) sin ωt: pressure pulsation within the main valve cover 16 itself A0 cos(kb・xb+kb・L) sin(ωt−
π): Pressure pulsation propagation from inside the sub-valve cover 19 (
3) Expanding the equation, cos (ka・xa) sinωt = cos (kb・xb+kb・L) sinωt, therefore, kb・xb+kb・L =
ka・xa+2nπ…(4)

(n=0.±1,±2,±3...
)

In order for the pressure pulsation to always be 0 at the openings A and B of the return gas passage, it is necessary that both of the above conditions are satisfied, and to do so, equations (2) and (4) can be used. All you have to do is form a coalition. That is, ka・xa+
ka・L = kb・xb+2nπkb・xb+k
From b・L = ka・xa+2nπ,

[0036]

[Math 7] and

[0037]

[Math. 8]

[0038] is obtained. The above formula (5) and the above (6
) is physically realizable and most simply,
n=1. By substituting n=1 into equations (5) and (6) and expanding the equations,

[0039]

[Math. 9] and

[0040]

[Math. 10] (However, γ=λb/λa) is obtained.

By the way, as explained above, λb and λa are the wavelengths of the pressure pulsating standing waves within the sub-valve cover 19 and the main valve cover 16, respectively.
These values were determined by experiment, and each valve cover 19
, 16, it has been confirmed that the length of the average propagation path R within 16 is equal to one circumference length.
If the return gas passage 30 is provided so that Equation 1] and Equation 2 can be obtained from Equation 9, pressure pulsations can be canceled out and operational noise can be reduced.

[0042]

[Effects of the Invention] As explained above, according to the present invention, since the entire length of the return gas passage and the relative positions of the return gas passage openings in the main bearing and the sub-bearing are set logically, pressure pulsations are canceled out. , which has the effect of reducing operating noise.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of essential parts of a two-cylinder rotary compressor, showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram of the average propagation path related to the sub-bearing and the sub-valve cover in the same embodiment.

FIG. 3 is a diagram illustrating the form of a return gas passage in the same embodiment.

FIG. 4 is a vertical sectional view of a two-cylinder rotary compressor, showing a conventional example.

[Explanation of symbols]

5... Rotating shaft, 11, 12... Eccentric crank part, 6... First cylinder, 7... Second cylinder, 9... Main bearing, 10... Sub bearing, 16... Main valve cover, 19... Sub valve cover,
30... Return gas passage, A... Opening, B... Opening, 1
5...First discharge port, 18...Second discharge port, R...
Average propagation path.

Claims (1)

[Claims] 1. A closed case houses an electric motor section and a compression mechanism section connected through a rotating shaft, and the compression mechanism section has a maximum eccentric position with respect to the rotating shaft having a phase difference of 180° from each other. A pair of eccentric crank portions are provided, and a first cylinder and a second cylinder are provided to accommodate the eccentric crank portions, respectively, so as to freely rotate eccentrically. A pivoting main bearing is provided, and a main valve cover is provided on the main bearing for once receiving gas compressed in the first cylinder and discharged from the first discharge port, and then guiding the gas to be discharged into the inside of the sealed case. , the second cylinder is provided with a sub-bearing that rotatably supports the end of the rotating shaft; A valve cover is provided, and a return gas passage is provided that guides the gas received by the secondary valve cover over the secondary bearing, the pair of cylinders, and the main bearing, and leads the gas into the main valve cover, the entire length of the return gas passage being L is [Equation 1], and the relative positions of the return gas passage openings provided in the main bearing and the sub-bearing are set so as to satisfy the relationship shown in [Equation 2]. compressor. (However, xb: Length along the average propagation path from the second discharge port xa: Length along the average propagation path from the first discharge port γ=Xb/Xa Xb: Average propagation path in the sub-valve cover One circumference length Xa of
: One circumference length of the average propagation path inside the main valve cover)