JPH0552193A - Oil returning device of compressor - Google Patents

Abstract

PURPOSE:To improve performance of a compressor by returning oil in a high pressure side inner chamber to open discharge gas to a low pressure side inner chamber and by reducing blow-by of gas to the low pressure side inner chamber. CONSTITUTION:A valve body 73 is arranged inside of a cylinder 70, and its primary side is faced to a working chamber 71 communicated through to a first capillary tube 81 extending from a high pressure side inner chamber. An energizing means 72 is arranged on the other side of the valve body 73. When the rising amount of oil staying in the high pressure side inner chamber is large and fluid flowing in an oil returning route (the first capillary tube 81) is oil, pressure of the working chamber 71 comes to be lower than the set value of the energizing means 72, and the oil returning route is opened to a low pressure side inner chamber 9b through a first flow passage 7a. When the oil rising amount is small and the fluid flowing in the oil returning route is gas, pressure of the working chamber 71 comes to be higher than the set value and released from a second flow passage 7b to the low pressure side working chamber 9b, and blow-by of gas is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil return device for a scroll compressor or the like used mainly in refrigeration systems.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Laid-Open No. 63-167084 and as shown in FIG. 6, a compression element C composed of a fixed scroll F and a movable scroll O is disposed inside a hermetic casing D, A low-pressure side internal chamber L for releasing the intake gas is defined below the compression element C, and a high-pressure side internal chamber H for releasing the compressed discharge gas is defined above the compression element C. A through hole R is provided in the fixed scroll F and the frame G that partition the inner chamber H and the low-pressure side inner chamber L, and the capillary tube T supported through the holder M is inserted into the through hole R, together with the discharge gas. The high pressure side inner chamber H
The oil lifted up to the bottom is returned to the oil reservoir provided at the bottom of the low pressure side inner chamber L through the capillary tube T.

[0003]

However, the high pressure side inner chamber H
The amount of oil lifted up to is not constant depending on the number of revolutions of the compressor, the pressure condition of the refrigerant gas, and the like. For example, the diameter of the capillary tube T is adjusted so that the oil can be properly returned under the condition that the maximum amount of oil rises. On the contrary, when the oil pressure is set to a large value, the hole of the capillary tube T is not liquid-sealed with oil when the amount of oil rise is small at the time of low speed operation,
A large amount of discharge gas is blown from the high pressure side inner chamber H toward the low pressure side inner chamber L, which causes a problem that the performance of the compressor is significantly deteriorated.

In the present invention, attention is paid to the fact that the pressure of the fluid flowing from the high-pressure side inner chamber to the low-pressure side inner chamber is such that the oil, which is a liquid, is always in a low pressure state with respect to the gas in the middle thereof. By operating the valve element by utilizing the pressure difference between the oil and gas, the oil smoothly returns to the low pressure side inner chamber, but it makes it difficult for the gas to return and good oil return is possible and the gas blows through. It is an object of the present invention to provide an oil return device for a compressor that can reduce the oil consumption and improve the performance.

[0005]

In order to achieve the above-mentioned main object, therefore, in the present invention, firstly, in a compressor for returning oil accumulated in the high pressure side inner chamber 9a to an oil sump 90 provided in the low pressure side inner chamber 9b. In the oil return device, the high pressure side inner chamber 9a and the low pressure side inner chamber 9
In the middle of the oil return path connecting with b, one side faces a working chamber 71 communicating with the oil return path, and a valve body 73 having a biasing means 72 is provided on the other side. When the pressure falls below a set value set by the urging means 72, the oil return path is routed through the low resistance first flow path 7a to the low pressure side inner chamber 9b.
Valve means 7 for opening the oil return path to the low pressure side working chamber 9b via the high resistance second flow path 7b when the pressure in the working chamber 71 exceeds the set value.

Secondly, the high pressure side inner chamber 9a and the low pressure side inner chamber 9b
In order to simplify the flow path configuration of the oil return path connecting between
In the first means, the first capillary tube 81 is interposed in the flow path connecting the high pressure side inner chamber 9a and the working chamber 71 in the valve means 7, and the second capillary tube 82 is interposed in the second flow path 7b. Let

Thirdly, in order to accommodate the oil return path compactly and to reduce the size of the entire structure, a flow path connecting the high pressure side inner chamber 9a and the working chamber 71 of the valve means 7 in the above first means. A first screw groove 83 provided between a cylinder 70 containing the valve body 73 and a fixing boss 77 fitted to the cylinder 70, and the cylinder 70 and the valve body 73 are provided in the second flow path 7b. Second screw groove 84 provided between
Intervened.

[0008]

The first means described above increases the amount of oil that rises to the high pressure side inner chamber 9a during high-speed operation, etc.
When the fluid flowing from the low pressure side inner chamber 9b to the oil return path is oil, the pressure of the action chamber 71 in the valve means 7 is below the set value set by the biasing means 72, and the oil return path has a low resistance. It is opened to the low-pressure side inner chamber 9b through one flow path 7a, which allows smooth oil return. On the other hand, when the amount of oil rising to the high pressure side inner chamber 9a is small at the time of low speed operation and the fluid flowing in the oil return path is gas, the pressure in the working chamber 71 exceeds the set value and the oil return path is It is opened to the low-pressure side working chamber 9b through the high-resistance second flow path 7b, whereby the blow-through amount of gas is reduced.

By the second means, the pressure drop between the high pressure side inner chamber 9a and the low pressure side inner chamber 9b can be made to occur in the first and second capillary tubes 81 and 82,
The flow path configuration of the oil return path can be simplified.

By the above-mentioned third means, the first and second screw grooves 83, 84 are used to compactly accommodate a long flow passage for causing a pressure drop between the high pressure side inner chamber 9a and the low pressure side inner chamber 9b. The overall structure can be made smaller.

[0011]

FIG. 3 shows a scroll type open type horizontal compressor to which the oil return device of the present invention is applied, in which a horizontal casing 9 having a body 91, a top 92 and a bottom 93 is provided with A fixed scroll 1 and a movable scroll 2 are provided via a frame 5 composed of the first and second frames 51 and 52.
A counterweight 41 having a drive shaft 4 connected to an external drive source via a pulley 40, and a swing link 4 fitted thereto
The movable scroll 2 is revolved around the fixed scroll 1 with the Oldham ring 21 interlocked with the movable scroll 2 via the suction pipe 94. The suction gas taken into the low-pressure side inner chamber 9b defined on the side is compressed in the compression chamber 30 defined between the scrolls, and the compressed discharge gas is discharged from the discharge hole 11 to the rear side of the fixed scroll 1. After being opened to the high pressure side inner chamber 9a defined by the above, it is taken out from the discharge pipe 96 to the outside.

A positive displacement oil supply pump 6 is interlocked with the drive shaft 4, and the oil supply pump 6 has a rotor 62 having an annular eccentric groove 61 forming an oil chamber and a eccentric groove via a spring 63. 61 is provided with a vane 64 for abutting the head, and a fixed amount is obtained for each rotation through an oil sump 90 formed in the bottom of the low pressure side inner chamber 9b through an oil suction passage 65 formed inside the second frame 52. The oil is pumped up, guided to the oil supply passage 43 provided inside the drive shaft 9 through the oil discharge passage 66 and the communication passage 67, and supplied to the main bearing 44 and the pin bearing 20 of the movable scroll 2, and The oil, after being supplied to these bearings, slides in the Oldham ring 21 and the movable scroll 2
The thrust plate 22 is splashed up to refuel each part.

An oil separator 9 is provided inside the high pressure side inner chamber 9a.
5 which is interposed between the bearings 44, 20 and the sliding grooves of the Oldham ring 21 and the thrust plate 22 and which overflows after the oil or floats in the low pressure side inner chamber 9b. At the same time, the oil lifted up in the compression chamber 30 and discharged from the discharge hole 11 is separated from the discharge gas.

With the above-mentioned structure, the high pressure side is used as an oil returning device for returning the oil separated in the oil separator 95 and accumulated at the bottom of the high pressure side inner chamber 9a to the oil sump 90 provided in the low pressure side inner chamber 9b. The valve means 7 described below is provided in the middle of the oil return path connecting the inner chamber 9a and the low pressure side inner chamber 9b.
The first capillary tube 81, which constitutes the first half of the oil return path, is held by the holder 80a and divides the high pressure side inner chamber 9a and the low pressure side inner chamber 9b into the fixed scroll 1 and the first frame. The holder 80a is fitted with a filter 80b.

The valve means 7 is as shown in FIG.
A cylinder 70 connected to the end portion of the first capillary tube 81 extending from the high-pressure side inner chamber 9a via a connection port 70a, and a working chamber 71 which is internally provided in the cylinder 70 and has one side communicating with the first capillary tube 81. To
A spool type valve element 73 having two lands 73a and 73b on which the biasing means 72 composed of a coil spring is disposed on the other side. It should be noted that on the open side of the cylinder 70, a low pressure communication hole 74 that opens to the low pressure side inner chamber 9b is provided.
A closing body 74 having a is fitted therein, and a sealing body composed of an O-ring 73c and a cap seal 73d is interposed on each of the lands 73a and 73b.

When the pressure in the working chamber 71 falls below the set value set by the urging means 72, the valve body 73 is moved to the left in FIG. 1 to provide a communication hole inside the valve body 73. Valve port 7 connected to the working chamber 71 through 73e
5 is opened to an outlet hole 76 opening in the side wall of the cylinder 70, and an oil return path is opened to the low pressure side inner chamber 9b via a low resistance first flow path 7a terminating at the outlet hole 76. ..

On the other hand, when the pressure in the working chamber 71 exceeds the set value, the valve body 73 is moved to the position shown in FIG. 1 to shut off the valve port 75 from the outlet hole 76. Further, it opens only to the second capillary tube 82 connected to the wall surface of the cylinder 70, and the oil return path is connected to the low pressure side through the high resistance second flow path 7b whose end is the outlet of the second capillary tube 82. Working chamber 9b
To open.

That is, the valve means 7 is the working chamber 7
The valve body 73 is actuated according to the magnitude of the fluid pressure introduced into the valve 1 to change the oil return passage, and as shown in FIG. 3, the pressure relationship between the oil and gas flowing through the passage is Taking advantage of the fact that the oil is always low and the gas is high, it is necessary to change the open flow path to the low pressure side inner chamber 9b depending on whether the fluid introduced into the working chamber 71 is oil or gas. To do.

The experimental model shown in FIG. 3 uses oil and nitrogen gas as the working fluid, and changes the length A of the first capillary tube 81 under the following conditions (a) to (c). The pressure at the connecting portion between the one capillary tube 81 and the second capillary tube 82, that is, the pressure P2 corresponding to the working chamber 71 is actually measured.

A. First and second capillary tubes 8
Diameter of 1,82 = 0.5 mm b. The inlet pressure of the first capillary tube 81 (pressure of the high pressure side inner chamber 9a) is constant at P1 = 16 kg / square centimeter c. Length B of second capillary tube 82 = 80 mm
As is clear from the result of FIG. 3, the oil pressure is always lower than the gas pressure regardless of the change in the length of the first capillary tube 81.

Due to the above configuration and the pressure difference between the oil and gas, the amount of oil rising to the high pressure side inner chamber 9a during high speed operation is large, and the high pressure side inner chamber 9a to the low pressure side inner chamber 9a.
When the fluid flowing in the oil return path toward b is oil, the pressure of the working chamber 71 in the valve means 7 is the biasing means 72.
Below the set value set in, the oil return path is opened to the low pressure side inner chamber 9b via the low resistance first flow path 7a, which allows smooth oil return, while at the time of low speed operation etc. The amount of oil rising to the high pressure side inner chamber 9a is small,
When the fluid flowing in the oil return path is gas, the pressure in the working chamber 71 exceeds the set value, and the oil return path is opened to the low pressure side working chamber 9b via the high resistance second flow path 7b, As a result, the amount of gas blown through is reduced.

Further, in the one shown in FIG. 1, the high pressure side inner chamber 9
Since the first capillary tube 81 is interposed in the flow path connecting the a and the action chamber 71 and the second capillary tube 82 is interposed in the second flow path 7b, the high pressure side inner chamber 9a
The pressure drop in the oil return path connecting between the low pressure side inner chamber 9b and the low pressure side inner chamber 9b can be provided by the capillary tubes 81 and 82, and the flow path configuration can be simplified.

Incidentally, in the structure shown in FIG. 1, a communication hole 73e communicating with the valve port 75 is provided inside the valve body 73,
Although the inlet portion of the second capillary tube 82 is communicated with the valve port 75, as shown in FIG.
In the middle of dividing the second capillary tube 82 into a short path 82a in the first half and a long path 82b in the second half without extending 3e, the second capillary tube 82 is extended from the connection port 70a located in the front stage of the working chamber 71. A branch pipe 82d is branched through a T-shaped branch 82c into the portion, and the branch pipe 82d is communicated with the valve port 75, so that when the gas blows out at a high pressure in the working chamber 71 side, as shown in the drawing, the first capillary tube 81 and the second capillary tube 82 are opened to the low-pressure side inner chamber 9b through the high-resistance second flow path 7b using the entire length of the first capillary tube 82. The tube 81, the short path 82a in the first half of the second capillary tube 82, and the branch pipe 82
It is also possible to open to the low pressure side inner chamber 9b through the low resistance first flow path 7a composed of d, the valve port 75 and the outlet hole 76.

1 and 4, the capillary tubes 81 and 82 are interposed in the oil return path, but as shown in FIG. 5, a large diameter tube extends from the high pressure side inner chamber 9a. The cylinder 70 having the fixed boss 77 fitted to one side of the valve body 73 is directly connected to the opening 801 of the through hole 800, the first screw groove 83 is provided on the outer peripheral surface of the fixed boss 77, and the valve body 7 is also connected.
Second thread grooves 84 are respectively provided on the outer peripheral surface of No. 3, and the first thread groove 83 is interposed in the flow path connecting the high-pressure side inner chamber 9a and the working chamber 71, and the working chamber 71 and the communication hole 73f.
The second screw groove 84 in the second flow path 7b on the high resistance side that connects the valve port 75 communicating with the low pressure side inner chamber 9b.
You may make it intervene.

In this case, when the pressure in the working chamber 71 is low and the oil is returned, the working chamber 71 is connected to the valve port 7 as shown in the figure.
5 is opened to the low pressure side inner chamber 9b through the low resistance first flow path 7a having the outlet hole 76 opening at 5 as the end, while the working chamber 7
When gas with high pressure of 1 is blown through, the outlet hole 76 is sealed by the land 73g of the valve body 73, and the working chamber 71 is provided with the valve port 75, the second screw groove 84, and the low pressure communication hole 70b provided in the bottom portion of the cylinder 70. Through the low pressure side inner chamber 9b
Open it to the public.

In the structure shown in FIG. 5, the flow passage between the high pressure side inner chamber 9a and the low pressure side inner chamber 9b is constituted by the screw grooves 83 and 84. It has the advantage that it can be compactly packed and the overall structure can be made smaller.

[0027]

As described above, according to the first aspect of the invention, the oil accumulated in the high pressure side inner chamber 9a can be smoothly returned to the low pressure side inner chamber 9b, and at the same time, the high pressure side inner chamber 9a can be changed to the low pressure side inner chamber. The amount of gas blown to 9b can be reduced, smooth oil return can be performed, and the performance of the compressor can be improved.

Further, according to the second aspect of the present invention, it is possible to simplify the flow passage structure of the oil return path connecting the high pressure side inner chamber 9a and the low pressure side inner chamber 9b.

According to the third aspect of the invention, the oil return path can be compactly housed, and the overall structure can be made compact.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a first embodiment of an oil return device according to the present invention.

FIG. 2 is a sectional view of a compressor including the oil return device.

FIG. 3 is a diagram in which a pressure relationship between oil and gas flowing through a flow channel is actually measured.

FIG. 4 is an enlarged sectional view showing a second embodiment.

FIG. 5 is an enlarged sectional view showing a third embodiment.

FIG. 6 is a sectional view of a conventional oil return device.

[Explanation of symbols]

 7 Valve Means 70 Cylinder 71 Working Chamber 72 Energizing Means 73 Valve Body 77 Fixed Boss 7a First Channel 7b Second Channel 81 First Capillary Tube 82 Second Capillary Tube 83 First Threaded Groove 84 Second Threaded Groove 90 Oil Reservoir 9a High pressure side inner chamber 9b Low pressure side inner chamber

Claims (3)

[Claims] 1. The oil accumulated in the high pressure side inner chamber 9a is supplied to the low pressure side inner chamber 9b.
In the oil return device of the compressor for returning to the oil reservoir 90 provided in
In the middle of the oil return path connecting the high pressure side inner chamber 9a and the low pressure side inner chamber 9b, the working chamber 7 whose one side communicates with the oil return path.
1, the valve body 73 is provided with the biasing means 72 on the other side, and when the pressure in the working chamber 71 is lower than the set value set by the biasing means 72, the oil return path having a low resistance is provided. The low pressure side working chamber is opened to the low pressure side inner chamber 9b via one flow passage 7a, and the oil return path is routed to the low pressure side working chamber via the high resistance second flow passage 7b when the pressure in the working chamber 71 exceeds the set value. 9b
An oil return device for a compressor, characterized in that a valve means (7) for opening the valve is interposed. 2. A first capillary tube 81 is provided in a flow path connecting the high pressure side inner chamber 9a and a working chamber 71 in the valve means 7, and a second capillary tube 82 is provided in a second flow path 7b. The oil return device for the compressor according to claim 1. 3. A cylinder 70 in which a valve body 73 is installed in a flow path connecting a high pressure side inner chamber 9a and a working chamber 71 in the valve means 7.
And a fixed boss 77 fitted to the cylinder 70, a first screw groove 83 provided between the second passage 7b and
The oil return device for a compressor according to claim 1, wherein a second screw groove 84 provided between the cylinder 70 and the valve body 73 is interposed in the.