JP2010223163A - Scroll type fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll type fluid machine capable of reducing frictional resistance received by a movable scroll caused by a thrust load by making optimal back pressure for its thrust load act on the movable scroll regardless of an operation state. <P>SOLUTION: The scroll type fluid machine has a back pressure chamber (52) formed at the back face side of the movable scroll (34), and a seal device (61) capable of partitioning the back pressure chamber (52) in the radial direction of the movable scroll (34). The seal device (61) includes large diameter and small diameter seal rings (62 and 62') separated from each other in the radial direction of the movable scroll (34), and openings (70 and 70') formed by dividing a part of these seal rings (62 and 62'), making the inside and outside of its seal rings communicate with each other, and closed by the thermal expansion of the seal rings. When linear expansion coefficients of the inside/outside seal rings are the same, the opening of the large diameter seal ring is narrowed in its opening width more than the opening of the small diameter seal ring. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a scroll type fluid machine, and more specifically, a sealed scroll type having a back pressure chamber for applying back pressure to the back of a movable scroll and having a seal ring capable of adjusting the back pressure in the back pressure chamber. The present invention relates to a fluid machine.

  This type of scroll type fluid machine includes a scroll unit that performs a series of refrigerant suction, compression, and discharge processes in a sealed container. Specifically, the scroll unit has fixed and movable scrolls that mesh with each other, and the fixed scroll is fixed to the hermetic container via a main shaft frame. On the other hand, the movable scroll is disposed between the spindle frame and the fixed scroll, and a back pressure chamber is formed on the back side of the end plate of the movable scroll. The back pressure chamber is formed by partitioning the back surface of the movable scroll and the end surface of the spindle frame facing the back surface by a seal ring device, and the high pressure refrigerant discharged from the scroll unit is stored in the back pressure chamber. Part, that is, the discharge pressure is guided. Therefore, the discharge pressure in the back pressure chamber becomes a back pressure against the thrust load acting on the movable scroll, and the orbiting motion of the movable scroll is smoothly performed.

Such a sealing device includes, for example, a double-structured seal ring that is attached to the end surface of the spindle frame and that is in sliding contact with the back surface of the movable scroll. This seal ring forms a back pressure chamber on the outside thereof, and exhibits a sealing function for maintaining the pressure in the back pressure chamber higher than the inside of the seal ring (Patent Document 1).
On the other hand, the other sealing device includes an annular back pressure chamber formed between the pair of seal rings and the inside of the movable scroll, and the compression chamber of the scroll unit is compressed at a predetermined timing during the refrigerant compression process. And a back pressure chamber are connected to each other, and a communication passage for supplying pressure in the compression chamber to the back pressure chamber is provided (Patent Document 2).

JP 2002-217172 A JP 2000-136782 A

  However, in the sealing device disclosed in Patent Document 1, since the pressure in the back pressure chamber, that is, the back pressure is kept constant regardless of the operating state of the fluid machine, the discharge pressure of the scroll unit, that is, When the thrust load acting on the movable scroll decreases, the back pressure applied to the movable scroll becomes excessive, and the smooth revolving orbiting motion of the movable scroll may be impaired.

Moreover, in the sealing device disclosed in Patent Document 2, a communication path must be formed in the movable scroll, so that the structure of the movable scroll is complicated.
The present invention has been made on the basis of the above circumstances, and the purpose thereof is to effectively apply a back pressure against the thrust load of the orbiting scroll to the orbiting scroll regardless of the driving situation. An object of the present invention is to provide a scroll type fluid machine that can prevent an increase in frictional resistance of a movable scroll and a decrease in compression efficiency of a scroll unit.

  To achieve the above object, a scroll type fluid machine according to claim 1 is housed in a housing and includes a fixed scroll and a movable scroll that orbits relative to the fixed scroll, and a movable scroll in the housing. The support member is disposed adjacent to the rear surface of the movable scroll and supports the main shaft that pivots the movable scroll, and has a support member having an end surface facing the rear surface of the movable scroll, and is formed between the rear surface of the movable scroll and the end surface of the support member A back pressure chamber through which a part of the working fluid discharged from the scroll unit is guided through the housing, and a seal device capable of partitioning the back pressure chamber with respect to the radial direction of the movable scroll. The inner and outer seal rings are spaced apart from each other in the radial direction, and a part of each seal ring is The temperature at which the opening of the outer seal ring is closed is provided, and is usually opened to allow the inside and outside of the seal ring to communicate with each other. The temperature is lower than the temperature of closing the opening of the inner seal ring.

  According to the scroll type fluid machine of claim 1, when the operation speed is increased and the pressure and temperature in the housing are increased, the temperature of the seal ring is increased and the opening of the outer seal ring is closed. In this case, the effective pressure receiving area on the back surface is only inside the outer seal ring. When the operating speed is further increased and the pressure and temperature in the housing are increased, the opening of the inner seal ring is also closed. In this case, the effective pressure receiving area on the back is further reduced only to the inner side of the inner seal ring. The

This makes it possible to effectively apply a back pressure against the movable scroll's thrust load to the movable scroll regardless of the operation status of the scroll type fluid machine, increasing the frictional resistance of the movable scroll, and the compression efficiency of the scroll unit. Can be prevented.
In the scroll type fluid machine according to claim 2, when the linear expansion coefficient of the inner and outer seal rings is the same, the opening width of the outer seal ring is narrower than the opening width of the inner seal ring. The optimum back pressure can be applied only by setting the width. Therefore, the structure of the sealing device is simplified, and the back pressure can be more effectively applied to the movable scroll.

  In the scroll type fluid machine according to claim 3, the opening width of the opening is defined between a pair of end faces spaced apart in the circumferential direction of the seal ring, the end faces being parallel to each other, and the diameter of the seal ring. Since it is inclined at an angle with respect to the direction, when these end faces are brought into close contact with each other, the contact area here is increased. Optimal back pressure can be applied.

  The scroll type fluid machine according to any one of claims 1 to 3 is movable by changing a substantial volume of the back pressure chamber, that is, an effective pressure receiving area of the movable scroll with respect to the back pressure, with respect to a pressure in the housing which varies depending on operating conditions. An optimal back pressure can be applied to the scroll, and a reduction in compression efficiency due to an excessive back pressure can be prevented.

It is a longitudinal cross-sectional view of the scroll compressor of one Example of this invention. It is an enlarged view of the peripheral part of the scroll unit of FIG. It is sectional drawing of a sealing device.

Hereinafter, an embodiment of a scroll type fluid machine according to the present invention will be described with reference to the drawings.
FIG. 1 shows a longitudinal sectional view of a compressor 1 as a scroll type fluid machine.
The compressor 1 is of a vertical type and is incorporated in a refrigeration circuit such as a refrigeration air conditioner or a heat pump type hot water heater. This refrigeration circuit includes a circulation path through which carbon dioxide refrigerant (hereinafter referred to as refrigerant), which is an example of a working fluid, circulates. The compressor 1 draws low-pressure refrigerant from the circulation path, and uses the compressed high-pressure medium as a circulation path. Dispense towards.

  The compressor 1 includes a housing 2, and the housing 2 includes a cylindrical body 4, and an upper lid 6 and a lower lid 8 that close the top and bottom of the body 4. These upper lid 6 and lower lid 8 are fitted into the body 4 in an airtight manner, and the inside of the housing 2 is in a sealed state. Further, a suction pipe 10 extends from the body portion 4, and the suction pipe 10 is connected to a circulation path. On the other hand, a discharge pipe 12 extends from an appropriate position of the upper lid 6, and the discharge pipe 12 is also connected to the circulation path.

An electric motor 14 is accommodated in the body 4, and the motor 14 has a main shaft, that is, a rotating shaft 16. The rotary shaft 16 protrudes up and down from the case of the motor 14, the upper end of the rotary shaft 16 is rotatably supported by the main shaft frame 18 via a bearing 17, and the lower end of the rotary shaft 16 is supported by a countershaft frame 22 via a bearing 20. It is supported rotatably.
A scroll unit 30 is disposed in the body 4 above the spindle frame 18, and the scroll unit 30 performs a series of processes of refrigerant suction, compression, and discharge. Specifically, the scroll unit 30 includes a movable scroll 34 and a fixed scroll 36. These movable and fixed scrolls 34 and 36 are provided with end plates 38 and 40, respectively, and the end plates 38 and 40 are integrally formed with spiral wraps that mesh with each other. A boss 44 is integrally formed on the back surface 50 of the end plate 38 of the movable scroll 34, and this boss 44 is rotatably supported on the upper end of the rotating shaft 16, that is, the eccentric shaft 48 via a bearing 46. . Therefore, when the motor 14, that is, the rotating shaft 16 thereof is rotated, the movable scroll 34 performs a turning motion around the axis of the rotating shaft 16 in a state where the rotation of the movable scroll 34 is prevented. In the figure, a mechanism for preventing the rotation of the movable scroll 34 is omitted.

  On the other hand, a discharge chamber 54 is formed between the end plate 40 of the fixed scroll 36 and the upper lid 6, and the discharge chamber 54 communicates not only with the discharge pipe 12 but also within the housing 2. A discharge hole 56 is formed through the center portion of the end plate 40 so that the discharge hole 56 can be opened and closed by a discharge valve 58. The discharge valve 58 is disposed on the back surface of the end plate 40. In addition, the discharge valve 58 is covered with a discharge cover 60, and the discharge cover 60 suppresses the propagation of sound generated when the discharge valve 58 is opened.

  The orbiting motion of the movable scroll 34 described above forms a compression chamber 42 between the spiral wraps of the movable scroll 34 and the fixed scroll 36, and the compression chamber 42 moves from the radially outer peripheral side of the spiral wrap toward the center. At this time, the volume gradually decreases. More specifically, the compression chamber 42 generated outside in the radial direction of the spiral wrap sucks and confines the low-pressure refrigerant introduced into the housing 2 through the suction pipe 10 described above. It is compressed in the process of moving toward the center of the spiral wrap. Thereafter, when the compression chamber 42 reaches the discharge hole 56, the refrigerant pressure in the compression chamber 42 overcomes the cutoff force of the discharge valve 58 to open the discharge valve 58, and high-pressure refrigerant from the compression chamber 42 passes through the discharge hole 56. It is discharged into the discharge chamber 54. While the high-pressure refrigerant in the discharge chamber 54 is sent to the circulation path through the discharge pipe 12, the housing 2 on the motor 14 side is filled from the discharge chamber 54, and back pressure is applied to the back surface 50 of the end plate 38 in the movable scroll 34. Make it work.

  Specifically, a predetermined back pressure chamber 52 is formed between the back surface 50 of the end plate 38 and the end surface 18A of the spindle frame 18 in the movable scroll 34, and the refrigerant in the housing 2 is transferred to the back pressure chamber 52 as described above. The back pressure is guided to the back pressure chamber 52 through the bearings 46 and 17. Such a back pressure acts against the thrust load on the back surface 50 of the movable scroll 34, so that the frictional resistance of the movable scroll 34 against the end surface 18a of the spindle frame 18 is reduced during the orbiting revolution of the movable scroll 34. To do.

On the other hand, an oil supply passage 28 is formed in the rotation shaft 16 of the motor 14, and the oil supply passage 28 extends over the entire length of the rotation shaft 16. An oil pump 24 is attached to the lower end of the rotating shaft 16, and a lower portion in the housing 2 is formed as an oil storage chamber 26 for the lubricating oil L.
The oil pump 24 is driven by the rotation of the rotating shaft 16, sucks the lubricating oil L in the oil storage chamber 26, and sends the sucked lubricating oil L into the oil supply path 28 of the rotating shaft 16. Therefore, the lubricating oil L is ejected from the upper end of the rotating shaft 16 through the oil supply passage 28 and flows down along the outer peripheral surface of the rotating shaft 16. Therefore, such a flow of lubricating oil lubricates the bearings 17 and 46 described above, while being guided into the back pressure chamber 52 together with the refrigerant, and sliding between the end face 18A of the spindle frame 18 and the movable scroll 34. It lubricates the part and also functions as a seal for the sliding surface in the scroll unit.

Here, since the pressure in the housing 2 is acting on the surface of the lubricating oil L in the oil storage chamber 26 as described above, such pressurization of the lubricating oil L reduces the load on the oil pump 24. The lubricating oil L guided to the back pressure chamber 52 is also the same as the pressure in the housing 2.
Further, a return port 32 for the lubricating oil L is formed at an appropriate position of the countershaft frame 22, and the lubricating oil L supplied to each sliding portion, the bearings 17, 46, etc. is stored through the return port 32. Returned to chamber 26.

The back pressure chamber 52 described above can be partitioned by the sealing device 61 in the radial direction of the movable scroll 34. The sealing device 61 will be described with reference to FIGS.
The sealing device 61 is disposed between the back surface 50 of the end plate 38 and the end surface 18 a of the spindle frame 18 in the movable scroll 34. The seal device 61 includes large-diameter and small-diameter seal rings 62 and 62 ′. These seal rings 62 and 62 ′ are attached to the end surface 18 A of the spindle frame 18 so as to be concentric with the axis of the rotary shaft 16. Slidably in contact with the back surface 50 of the lens.

Specifically, two annular grooves 64 are formed concentrically on the end surface 18 a of the spindle frame 18, and seal rings 62 and 62 ′ are fitted into these annular grooves 64, respectively.
Preferably, an elastic body 66 made of a spring material is sandwiched between the bottom of the annular groove 64 and the seal rings 62, 62 ′. These elastic bodies 66 press the seal rings 62 and 62 ′ against the back surface 50 of the movable scroll 34, and can increase the adhesion between the seal rings 62 and 62 ′ and the back surface 50.

  As shown in FIG. 3, openings 70 and 70 ′ are formed in the seal rings 62 and 62 ′ by dividing the seal rings 62 and 62 ′ so that the inside and the outside communicate with each other. These openings 70 and 70 'have end faces 62c and 62d and 62c' and 62d 'which are spaced apart from each other in the circumferential direction of the seal ring and are parallel to each other, and these end faces are angled with respect to the radial direction of the seal ring. Is inclined.

  The openings 70 and 70 'described above are open when the seal rings 62 and 62' are in a normal temperature state. However, as the temperature of the seal rings 62, 62 ′ increases, the opening of the openings 70, 70 ′ gradually decreases as the seal rings 62, 62 ′ expand in the circumferential direction due to thermal expansion, and And finally closed. At this time, since the end faces 62c and 62d of the seal ring 62 and the end faces 62c 'and 62d' of the seal ring 62 'are parallel to each other, they are in good contact with each other.

Further, when the linear expansion coefficients of the seal rings 62 and 62 ′ are the same, the opening degree of the opening 70 ′ is equal to that of the opening 70 in the normal state of the seal rings 62 and 62 ′, as is apparent from FIG. It is larger than the opening.
Therefore, when the compressor is operated at low speed and the pressure in the housing 2, i.e. its temperature, is low, the openings 70, 70 'are both open. In this case, the back pressure chamber 52 is secured in a form including the entire area of the back surface 50 of the movable scroll 34, and the effective pressure receiving area of the back surface 50 is large.

Thereafter, when the operating speed of the compressor is increased and the pressure and temperature in the housing 2 are increased accordingly, the opening 70 of the seal ring 62 is first closed. In this case, the effective pressure receiving area of the back surface 50 is reduced only inside the seal ring 62.
When the operating speed of the compressor further increases and the pressure and temperature in the housing 2 increase, the opening 70 ′ of the seal ring 62 ′ also closes. In this case, the effective pressure receiving area of the back surface 50 is the seal ring. It is further reduced only to the inside of 62 '.

  As described above, even if the pressure (temperature) in the housing 2 varies depending on the operating state of the compressor, the effective pressure receiving area of the back pressure chamber 52, that is, the volume thereof can be changed. 2, an optimum back pressure against the thrust load of the movable scroll 34 can be applied to the movable scroll 34 regardless of the pressure, and the back pressure of the movable scroll 34 does not become excessive. As a result, a smooth turning motion of the movable scroll 34 is ensured, and a reduction in compression efficiency can be prevented.

  Further, since the end surfaces defining the opening widths of the openings 70 and 70 ′ are inclined with respect to the radial direction of the seal ring, the end surfaces 62C and 62d and the end surfaces 62c ′ and 62d ′ are in close contact with each other. At this time, since the contact area here is increased, the effective pressure receiving area of the back surface 50, that is, the volume of the back pressure chamber 52 can be reliably changed, and a more optimal back pressure can be applied by the movable scroll 34.

The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the embodiment of the present invention.
For example, in the above embodiment, the end surfaces of the openings 70 and 70 'are formed as flat surfaces along the axis of the seal ring. However, the present invention is not limited to this, and is inclined with respect to the axis of the seal ring, for example. They may have complementary shapes that can mesh with each other, such as an end face or an L-shape, or the like, as long as the seal ring is thermally expanded as long as it is in close contact with each other.

In the above embodiment, the sealing device 61 is composed of a double seal ring. However, the seal ring may be triple or more. In this case, the opening of the inner seal ring is enlarged stepwise. It only has to be.
Further, when the linear expansion coefficients of the seal rings 62 and 62 ′ are different, the opening widths of the openings 70 and 70 ′ may be the same as long as the linear expansion coefficient of the seal ring 62 is larger.

  In the above embodiment, the seal rings 62 and 62 ′ are attached via the annular groove 64 formed in the end surface 18 a of the spindle frame 18, but the annular groove formed in the back surface 50 of the movable scroll 34. 64 may be attached.

DESCRIPTION OF SYMBOLS 1 Scroll type fluid machine 2 Housing 16 Rotating shaft 18 Spindle frame 30 Scroll unit 34 Movable scroll 36 Fixed scroll 42 Compression chamber 50 Back surface 52 Back pressure chamber 61 Sealing device 62, 62 'Seal ring 62c, 62d End surface 64 Annular groove 70, 70 ' Aperture

Claims (3)

A scroll unit that is housed in a housing and includes a fixed scroll and a movable scroll that orbits relative to the fixed scroll;
A support member disposed in the housing adjacent to the back surface of the movable scroll, supporting a main shaft for orbiting the movable scroll, and having an end surface facing the back surface of the movable scroll;
A back pressure chamber formed between a back surface of the movable scroll and an end surface of the support member, and a part of the working fluid discharged from the scroll unit is guided through the housing;
A sealing device capable of partitioning the back pressure chamber with respect to the radial direction of the movable scroll;
The sealing device includes:
An inner and outer seal ring arranged spaced apart from each other in the radial direction of the movable scroll;
A part of each of the seal rings is provided, and is usually opened to communicate the inside and outside of the seal ring, but includes an opening that is closed by thermal expansion of the seal ring,
A scroll type fluid machine characterized in that a temperature for closing the opening of the outer seal ring is lower than a temperature for closing the opening of the inner seal ring.   2. The scroll according to claim 1, wherein when the linear expansion coefficient of the inner and outer seal rings is the same, the opening width of the outer seal ring is narrower than the opening width of the inner seal ring. Type fluid machine.   The opening width of the opening is defined between a pair of end faces spaced in the circumferential direction of the seal ring, the end faces being parallel to each other and inclined at an angle with respect to the radial direction of the seal ring. The scroll type fluid machine according to claim 1, wherein the scroll type fluid machine is provided.

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