JP3073044B2 - 2-cylinder rotary compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art For example, a two-cylinder rotary compressor has been frequently used in a refrigeration cycle apparatus. The two-cylinder rotary compressor is generally configured as shown in FIG.

[0003] In the figure, reference numeral 1 denotes a sealed case, in which an electric compressor main body 2 is accommodated. The electric compressor main body 2 is configured by connecting an upper motor unit 3 and a lower compression mechanism unit 4 via a rotating shaft 5.

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

The first cylinder 6 of the rotating shaft 5
The eccentric crank portions 11 and 12 which are 180 ° out of phase with each other are provided in portions corresponding to the inside and the second cylinder 7.

A first roller 13 and a second roller 14 are fitted on the peripheral surfaces of the eccentric crank portions 11 and 12 and are accommodated in the cylinders 6 and 7 so as to be eccentrically rotatable. .

The main bearing 9 is provided with a first discharge port 15 which communicates with the first cylinder 6 and is opened / closed. The first discharge port 15 is further surrounded by an internal cavity. The main valve cover 16 is provided.

The main valve cover 16 has the same outer peripheral end as the outer peripheral end of the main bearing 9, and its inner peripheral end is in contact with the rotating shaft 5 pivotal support of the main bearing 9. A gas outlet 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 closed case 1. The secondary bearing 10 is provided with a second discharge port 18, and further provided with a secondary valve cover 19 surrounding 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 peripheral end of the sub-bearing 10, and covers the lower end of the rotating shaft 5 and the sub-bearing 10 at its end surface.
That is, the second discharge port 18 is hermetically covered with an internal cavity.

Such first and second cylinders 6, 7
And the intermediate partition plate / frame 8 and the main and auxiliary bearings 9 and 10.
Is provided integrally with the return gas passage 20.
That is, the return gas passage 20 is provided in a straight line in the vertical direction, the upper end opening is communicated with the internal cavity of the main valve cover 16, and the lower end opening is connected to the auxiliary valve cover 19.
Is communicated with the internal cavity.

On the other hand, here, only the suction pipe 21 connected to the second cylinder 7 is shown, and the suction pipe 21 penetrates through the closed case 1 and communicates with an evaporator (not shown) via a suction cup 22 outside at the outside. Is done. The first cylinder 6 is also provided with a suction pipe in exactly the same structure, and communicates with the evaporator via another suction cup. On the other hand, a discharge pipe 23 is provided at the upper end of the closed case 1.
Are connected to communicate the inside of the closed case 1 with a condenser not shown here.

However, with the rotation of the rotating shaft 5,
The eccentric crank portions 11 and 12 make eccentric rotational motion together with the rollers 13 and 14 fitted thereto, and the refrigerant evaporated by the evaporator is transferred from the suction cups 22 through the suction pipes 21 to the cylinders 6 and 7 respectively. Inhale into.

In each of the cylinders 6 and 7, the sucked gas is compressed, and the compressed gas in the upper first cylinder 6 is supplied from the first discharge port 15 to the main valve cover 1.
6 is discharged. The gas compressed in the lower second cylinder 7 is discharged from the second discharge port 18 into the sub-valve cover 19.

The gas in 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 container 6, they are discharged into the closed case 1 from the gas discharge ports 17. The inside of the closed case 1 is filled with the compressed and high-pressure gas, and is led out of the discharge pipe 23 provided at the upper part to the condenser.

[0015]

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 at the shortest distance.

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

Since the internal cavities of the valve covers 16 and 19 are communicated with each other by a return gas passage 20 provided appropriately, the pressure pulsation generated in the internal cavities of the main valve cover 16 and the auxiliary valve cover 19 The pressure pulsations generated in the internal cavity are likely to interfere with each other, and there is a drawback that the operation noise caused by the pressure pulsations of these discharge gases is large.

The present invention has been made in view of the above-described circumstances, and an object thereof is to determine the total 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 the pressure. Considering the conditions such as the wavelength of the pulsating standing wave, the same wavelength constant, the average propagation path length from each discharge port to the opening of the return gas passage, and the like, logically calculating and setting each valve An object of the present invention is to provide a two-cylinder rotary compressor capable of canceling pressure pulsation generated in an internal cavity of a cover and reliably reducing operating noise.

[0019]

In order to achieve the above object, the present invention comprises an electric motor and a compression mechanism connected via a rotating shaft in a sealed case. A pair of eccentric crank portions having a maximum eccentric position having a phase difference of 180 ° with respect to the rotating shaft are provided, and a first cylinder and a second cylinder accommodating the eccentric crank portions are respectively eccentrically rotatable; The first cylinder is provided with a main bearing that rotatably supports an intermediate portion of the rotating shaft, and the main bearing temporarily receives a gas compressed in the first cylinder and discharged from the first discharge port. And a main valve cover for guiding discharge from the inside of the closed case, and a sub-bearing for rotatably supporting the end of the rotating shaft in the second cylinder is provided. The sub-bearing is compressed in the second cylinder. Second A return valve for temporarily receiving gas discharged from the outlet port, and a return gas for guiding the gas received by the auxiliary valve cover over the auxiliary bearing, the pair of cylinders and the main bearing, and guiding the gas into the main valve cover; A passage is provided, and the total length L of the return gas passage is:

[0020]

(Equation 3) The relative positions of the return gas passage openings provided in the main bearing and the sub-bearing, respectively,

[0021]

(Equation 4) A two-cylinder rotary compressor characterized by the following relationship. (However, xb: opening of the second discharge port and the auxiliary bearing
The length along the average propagation path between xa: first discharge port and an average length along the propagation path γ = Xb / Xa Xb between the openings of the main bearing: 1 average propagation path inside the auxiliary valve cover Perimeter. Xa: one circumference of the average propagation path in the main valve cover. ).

[0022]

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 described above, pressure pulsations generated in the internal cavities of the main and sub-valve covers are reduced. Offset.

[0023]

An embodiment of the present invention will be described below with reference to the drawings.

The overall structure of the two-cylinder rotary compressor is as described above with reference to FIG. 4, and a new description will be omitted.
1 to 3 show the main part of the compression mechanism 4, except for the return gas passage 30, which will be described later, since the other components are the same as those described above. Detailed description is omitted.

The return gas passage 30 is formed 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 auxiliary bearing 10
Through.

To be more specific, the main bearing 9 and the sub bearing 1
In the case of 0, the openings are provided in parallel with the axial direction of the rotating shaft 5 from the openings A and B, that is, in the vertical direction. Mating surface of main bearing 9 and first cylinder 6 and sub bearing 10
A groove having a semicircular cross section is provided on each of the mating surfaces of the first and second cylinders 7 to form a circular cross section, and are formed in an arc shape with a predetermined radius of curvature. And, at these tip portions, the first cylinder 6, the partition plate / frame 8 and the second cylinder 7 are provided so as to penetrate vertically in the vertical direction. Such an overall length L of the return gas passage 30 extending between the opening A of the main bearing 9 and the opening B of the sub-bearing 10 is as follows:

[0027]

(Equation 5) Is set to Where γ = Xb / Xa Xb: one circumference of the average propagation path R in the sub valve cover 19 Xa: one circumference of the average propagation path R in the main valve cover 16

The above average propagation path R is defined as described below. FIG. 2 illustrates the average propagation path R in the auxiliary valve cover 19. That is, the average propagation path R is
The cross-sectional shape along the direction is formed relatively simply
In the valve cover 19, a shaft in the valve cover is used.
Adopt a cross section intermediate in height in the direction. Then, the angle line S extends at a certain angle from the axis of the rotating shaft 5. This angle line S
An intermediate point m between the inner surface of the peripheral wall of the auxiliary valve cover 19 and the peripheral surface of the rotary shaft pivot 10a of the auxiliary bearing 10 is set.
Extending the angle line S over an angle of 0 ° to 360 °,
An intermediate point m on each angle line S between the inner surface of the peripheral wall of the auxiliary valve cover 19 and the peripheral surface of the rotary shaft pivot 10a of the auxiliary bearing 10 is set. A broken line connecting all the intermediate points m is an average propagation path R in the sub-valve cover 19.

The average propagation path R in the main valve cover 16 is similarly obtained by connecting an intermediate point between the inner surface of the peripheral wall of the main valve cover 16 and the peripheral surface of the rotary shaft support 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 described with reference to FIG. That is, the intersection between the line connecting the axis of the rotary shaft 5 and the first discharge port 15 provided in the main bearing 9 and the above-described average propagation path R in the main valve cover 16 (not shown here) is a starting point. Xa is the length taken along the average propagation path R and in the direction of rotation of the rotation axis 5 from the line connecting the axis of the rotation axis 5 to the opening A and the intersection with the average propagation path R. And

On the other hand, starting from the intersection of the line connecting the axis of the rotary shaft 5 and the second discharge port 18 provided on the sub-bearing 10 side with the average propagation path R in the sub-valve cover 19, Assuming that the length taken from the line connecting the axis of the shaft 5 to the opening B and the intersection with the average propagation path R along the average propagation path R in the rotation direction of the rotating shaft 5 is xb, The relative positions of xa and xb are

[0032]

(Equation 6) It is set to be.

By the way, the pressure pulsation at the opening B of the return gas passage 30 is such that the pressure pulsation due to the compression action in the first cylinder 6 is caused by the propagation component passing through the return gas passage 30 and the second cylinder 6. 7 is the sum of the pressure pulsation components generated by the compression action. And
If this sum is zero, no pressure pulsation will result, and the operating noise can be reduced. This can be expressed by the following equation. _{A 0 cos (kb · xb)} sin (ωt-π) + A 0 cos (ka · xa + ka · L) sinωt = 0 ... (1) and must meet the conditions to be. A ₀ cos (kb · xb) sin (ωt−π): pressure pulsation in the sub valve cover 19 itself A ₀ cos (ka · xa + ka · L) sin ωt: pressure pulsation propagation from inside the main valve cover 16 A ₀ : magnitude of pressure pulsation kb: wavelength constant (= 2π / λb) of pressure pulsation standing wave in sub valve cover 19 xb: second discharge port 18 and opening B of sub bearing 10
Average propagation path length along the R between the [lambda] b: the wavelength of the pressure pulsation the standing wave in the sub valve cover 19 omega: angular frequency (= 2πf) f: frequency t: time [pi: crank phase angle ka : Wavelength constant of the pressure pulsating standing wave in the main valve cover 16 (= 2π / λa) xa: on the average propagation path R between the first discharge port 15 and the opening A of the main bearing 9 Along the length λa: the wavelength of the pressure pulsation standing wave in the main valve cover 16 L: the total length of the return gas passage 30 extending between the opening A and the opening B When the above equation (1) is developed, cos ( kb · xb) sinωt = cos (ka · xa + ka · L) sinωt, and therefore ka · xa + ka · L = kb · xb + 2nπ (2) (n = 0. ± 1, ± 2, ± 3...)

On the other hand, the pressure pulsation at the opening A of the return gas passage 30 is caused by the pressure pulsation due to the compression action in the second cylinder 7 and the propagation component passing through the return gas passage 30 and the first cylinder 6. It is the sum of the pressure pulsation components generated by the compression action in the inside. If the sum is 0, pressure pulsation does not occur as a result, and operation noise can be reduced. This can be expressed by the following equation. A ₀ cos (ka · xa) sinωt + A ₀ cos (kb · xb + kb · L) sin (ωt−π) = 0 The condition (3) must be satisfied. A ₀ cos (ka · xa) sinωt: pressure pulsation in the main valve cover 16 itself A ₀ cos (kb · xb + kb · L) sin (ωt−
π): Propagation of pressure pulsation from inside the sub-valve cover 19 When the above equation (3) is expanded, cos (ka · xa) sinωt = cos (kb · xb + kb · L) sinωt, and therefore kb · xb + kb · L = ka Xa + 2nπ (4) (n = 0. ± 1, ± 2, ± 3 ...)

Openings A and B of the return gas passage
In order for the pressure pulsation to always be zero, it is necessary that both of the above conditions be satisfied. For this purpose, the equations (2) and (4) may be combined. That is, from ka · xa + ka · L = kb · xb + 2nπ kb · xb + kb · L = ka · xa + 2nπ,

[0036]

(Equation 7) and

[0037]

(Equation 8)

Is obtained. In the above equations (5) and (6), it is physically feasible, and in the simplest case, n = 1. By substituting n = 1 into equations (5) and (6) and expanding the equation,

[0039]

(Equation 9) and

[0040]

(Equation 10) (However, γ = λb / λa) is obtained.

As described above, λb and λa are the wavelengths of the pressure pulsating standing waves in the sub-valve cover 19 and the main valve cover 16, respectively, as described above.
These values were experimentally determined for each valve cover 1
Since it has been confirmed that the length is equal to one circumference of the average propagation path R in 9 and 16, finally [Equation 1] is obtained from [Equation 10] and [Equation 2] is obtained from [Equation 9]. ] Is obtained, the pressure pulsation is canceled out, and the result that the operation noise is reduced is obtained.

[0042]

As described above, according to the present invention, since the total 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 logically set, the pressure pulsation is canceled. This has the effect of reducing operating noise.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of an average propagation path relating to a sub bearing and a sub valve cover of the embodiment.

FIG. 3 is a diagram illustrating a form of a return gas passage according to the embodiment.

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

[Explanation of symbols]

Reference numeral 5: rotating shaft, 11, 12: eccentric crank portion, 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.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F04C 23/00-29/10

Claims (1)

(57) [Claims] An electric motor and a compression mechanism connected via a rotary shaft are accommodated in a sealed case. The compression mechanism has a maximum eccentric position of 180 ° relative to the rotary shaft. Are provided, a first cylinder and a second cylinder are accommodated eccentrically and rotatably, respectively, and these eccentric crank parts are provided. A main bearing for pivoting is provided, and the main bearing is provided with a main valve cover for once receiving the gas compressed in the first cylinder and discharged from the first discharge port, and then guiding the gas discharged into the closed case. The second cylinder is provided with a sub-bearing for rotatably supporting the end of the rotary shaft. The sub-bearing temporarily receives gas compressed in the second cylinder and discharged from the second discharge port. Bal A cover is provided, and a return gas passage is provided to guide the gas received by the sub-valve cover over the sub-bearing, the pair of cylinders and the main bearing, and to guide the gas into the main valve cover. Is: And the relative positions of the return gas passage openings provided in the main bearing and the sub bearing, respectively, are as follows: A two-cylinder rotary compressor characterized by the following relationship. (However, xb: opening of the second discharge port and the auxiliary bearing
The length along the average propagation path between xa: first discharge port and an average length along the propagation path γ = Xb / Xa Xb between the openings of the main bearing: 1 average propagation path inside the auxiliary valve cover Perimeter Xa: One circumference of the average propagation path in the main valve cover)