WO2017124964A1

WO2017124964A1 - Method for reducing back pressure fluctuation of scroll compressor, and scroll compressor

Info

Publication number: WO2017124964A1
Application number: PCT/CN2017/071010
Authority: WO
Inventors: 陈洪辉
Original assignee: 广东美的暖通设备有限公司; 美的集团股份有限公司
Priority date: 2016-01-18
Filing date: 2017-01-12
Publication date: 2017-07-27

Abstract

A scroll compressor, and a method for reducing the back pressure fluctuation of the scroll compressor. The center of a frame (9) of the scroll compressor is provided with a cavity for facilitating the rotation of a sliding bearing, and the cavity constitutes a high-pressure oil chamber (15) which is in communication with a lubricating oil tank; the edge of the frame (9) is provided with a ring groove, and forms a back-pressure chamber (2) together with a static scroll plate (1); an oil inlet passage (5) is arranged on a kinetic scroll substrate (14) in the radial direction, and the oil inlet passage (5) communicates with the high-pressure oil chamber (15) and the back-pressure chamber (2); a throttling means is arranged in the oil inlet passage (5) to pump the high-pressure lubricating oil out of the lubricating oil tank of the scroll compressor. The high-pressure lubricating oil is depressurized to form a medium-pressure lubricating oil, and then the medium-pressure lubricating oil is introduced into the back-pressure chamber (2) to provide pressure for the back pressure chamber (2), thus ensuring consistent pressure in the back-pressure chamber, thereby preventing up-and-down fluctuations of the kinetic scroll plate, and effectively providing sealing between the kinetic scroll plate and the static scroll plate.

Description

Method for reducing back pressure fluctuation of scroll compressor and scroll compressor

Technical field

The invention relates to the technical field of compressors, in particular to a method for reducing back pressure fluctuation of a scroll compressor and a scroll compressor.

Background technique

When the scroll compressor is in operation, the orbiting scroll is easily undulating due to the eccentric disc, which causes a gap between the orbiting scroll and the fixed scroll due to fluctuations, which directly affects the movable scroll and the static The tightness between the scrolls and the overall performance of the compressor. The main factor that causes the orbiting scroll to fluctuate up and down, and affects the tightness between the orbiting scroll and the fixed scroll is the fluctuation of the pressure in the back pressure chamber of the scroll compressor.

At present, the back pressure chamber of a general scroll compressor supplies pressure by a high pressure gas, and the gas in the back pressure chamber is introduced by a compression chamber, and the gas pressure in the pressure chamber is supplied through the gas of the compressor. Since the gas pressure in the compression chamber changes from time to time, the gas pressure in the back pressure chamber also changes, so that the pressure fluctuation in the back pressure chamber is relatively large, so that the orbiting scroll will be fluctuating up and down. The steady state affects the reliability of the scroll and causes internal leakage between the compression chambers and affects the performance of the compressor.

Summary of the invention

(1) Technical problems to be solved

The technical problem to be solved by the present invention is to provide a method for reducing the back pressure fluctuation of a scroll compressor and a scroll compressor, which is introduced into the back pressure by depressurizing the high pressure oil in the compressor. In the chamber, the stable pressure is provided for the back pressure chamber, which solves the problem that the pressure in the back pressure chamber is unstable in the prior art, resulting in poor sealing between the movable scroll and the fixed scroll.

(2) Technical plan

In order to solve the above technical problems, the present invention provides a method of reducing back pressure fluctuation of a scroll compressor and a scroll compressor.

A method for reducing back pressure fluctuation of a scroll compressor, extracting high-pressure lubricating oil in a lubricating oil pool of a scroll compressor, depressurizing the high-pressure lubricating oil to form a medium-pressure lubricating oil, and introducing the medium-pressure lubricating oil into To the back pressure chamber of the scroll compressor, the back pressure chamber is pressurized.

In some embodiments, the method of reducing back pressure fluctuations of a scroll compressor includes the following steps:

S1, a vane pump is disposed at a bottom of a crankshaft of the scroll compressor, and the vane pump extracts high-pressure lubricating oil in the lubricating oil pool connected thereto, and introduces the high-pressure lubricating oil into the movable scroll through an oil guiding hole of the crankshaft. Disc, frame and crankshaft In a high pressure oil chamber;

S2, an oil inlet passage communicating with the high pressure chamber is disposed on an orbiting scroll of the scroll compressor, and high pressure lubricating oil in the high pressure oil chamber is introduced into the oil inlet passage, and The high pressure lubricating oil is depressurized in the oil inlet passage to form a medium pressure lubricating oil;

S3, a through hole connecting the oil inlet passage and the oil groove on the movable scroll substrate is disposed on the movable scroll, and the medium pressure lubricating oil is introduced into the back pressure chamber connected thereto through the oil groove and passes through the The medium pressure lubricating oil provides pressure to the back pressure chamber.

In some embodiments, in the foregoing step S2, a throttle device is disposed in the oil inlet passage, and the high pressure lubricating oil is depressurized by the throttle device.

In some embodiments, the aforementioned throttling device is a throttle rod disposed axially along the oil inlet passage, and the pressure reducing range of the high-pressure lubricating oil is adjusted by adjusting a cross-sectional area of the throttle rod.

A scroll compressor includes a fixed scroll, an orbiting scroll, a frame and a crankshaft which are disposed in order from top to bottom, and the fixed scroll is disposed opposite to the orbiting scroll, the frame For supporting the orbiting scroll, the top of the crankshaft passes through the axis of the frame and is coupled to a sliding bearing at the bottom of the orbiting scroll; the center of the frame is open to facilitate the sliding a cavity in which the bearing rotates, the cavity forming a high pressure oil chamber communicating with the lubricating oil pool; an edge of the frame is provided with a ring groove, and a back pressure chamber is formed with the static scroll; the movable scroll An oil inlet passage is formed in the radial direction of the disk substrate, and the oil inlet passage communicates with the high pressure oil chamber and the back pressure chamber, and the oil inlet passage is provided with a throttle device.

In some embodiments, the crankshaft is provided with an oil guiding hole in the axial direction, a bottom of the crankshaft is provided with a vane pump, the vane pump communicates with the lubricating oil pool, and one end of the oil guiding hole communicates with the high pressure oil The chamber is connected to the vane pump at the other end.

In some embodiments, the bottom of the sliding bearing defines a receiving cavity, a top end of the crankshaft is inserted into the receiving cavity, and the movable scroll and the fixed scroll are eccentrically disposed; the receiving cavity The oil guiding hole, the high pressure oil chamber and the oil inlet passage are respectively connected.

In some embodiments, the accommodating cavity is disposed at an axis of the orbiting scroll, and a top of the crankshaft is eccentrically provided with a connecting portion, the connecting portion is inserted into the receiving cavity; the crankshaft connection Driving a motor, the driving motor driving the crankshaft to drive the orbiting scroll to rotate synchronously.

In some embodiments, the top of the movable scroll substrate is provided with an annular oil groove, and an end of the oil inlet passage adjacent to the edge of the movable scroll communicates with the oil groove, and the oil groove communicates with the back pressure chamber.

In some embodiments, the aforementioned throttling device is a throttle bar disposed axially along the oil inlet passage.

In some embodiments, the frame is provided with a sealing ring for sealing the orbiting scroll and the frame.

(3) Beneficial effects

The above technical solution of the present invention has the following beneficial effects:

The invention provides a method for reducing the back pressure fluctuation of a scroll compressor, which is high in the lubricating oil pool of the scroll compressor The lubricating oil is extracted, the high pressure lubricating oil is depressurized to form a medium pressure lubricating oil, and the medium pressure lubricating oil is introduced into the back pressure chamber of the scroll compressor, since the pressure of the high pressure lubricating oil is non-fluctuating when the compressor is running, The pressure of the medium-pressure lubricating oil formed after the pressure reduction is also stable, so that the medium-pressure lubricating oil introduced into the back pressure chamber can supply a stable pressure to the back pressure chamber, ensure the pressure of the back pressure chamber is constant, and prevent the movable scroll. Fluctuating up and down, thus avoiding the phenomenon of internal leakage, effectively improving the tightness between the movable scroll and the fixed scroll.

The invention provides a scroll compressor. The center of the frame is provided with a high-pressure oil chamber communicating with the lubricating oil pool. The edge of the frame is provided with a ring groove, and forms a back pressure chamber with the fixed scroll, and the movable scroll An oil inlet passage is formed in the radial direction of the disk substrate, and the oil inlet passage communicates with the high pressure oil chamber and the back pressure chamber, and a throttle device is disposed in the oil inlet passage. The pressure in the back pressure chamber of the scroll compressor is supplied by a throttle device to the medium-pressure lubricating oil formed by depressurizing the high-pressure lubricating oil in the high-pressure oil chamber. Since the pressure of the medium-pressure lubricating oil is stable, it is possible to provide a stable pressure to the back pressure chamber by introducing the medium-pressure lubricating oil in the back pressure chamber, thereby ensuring the pressure of the back pressure chamber is constant, preventing the movable scroll from fluctuating up and down, thereby avoiding The phenomenon of internal leakage occurs to effectively improve the sealing between the movable scroll and the fixed scroll.

According to the scroll compressor of the present invention, since the medium-pressure lubricating oil flows in the oil groove of the movable scroll substrate, an oil film is formed between the movable scroll and the fixed scroll, and the movable scroll can be further improved. Sealing between the fixed scroll and the fixed scroll.

DRAWINGS

Figure 1 is a schematic structural view of a scroll compressor of the present invention;

Figure 2 is an enlarged view of a portion A in Figure 1;

Figure 3 is a cross-sectional view of the movable scroll of the present invention;

Figure 4 is a plan view of the movable scroll of the present invention;

Figure 5 is a graph showing the relationship between the swing angle of the scroll compressor and the pressure in the back pressure chamber of the present invention.

Among them, 1: static scroll; 2: back pressure chamber; 3: second oil hole; 4: throttle rod; 5: oil inlet passage; 6: crankshaft; 7: vane pump; 8: oil guide hole; : rack; 10: accommodating chamber; 11: sealing ring; 12: oil groove; 13: moving scroll; 14: moving scroll substrate; 15: high pressure oil chamber; 16: first oil hole.

detailed description

Embodiments of the present invention will be further described in detail below with reference to the drawings and embodiments. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that, unless otherwise stated, the meaning of "a plurality" is two or more; the terms "upper", "lower", "left", "right", "inside" The orientation or positional relationship of the indications of "outside", "front end", "back end", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present invention and Simplifying the description, and not indicating or implying that the device or component referred to must have a particular orientation, constructed and operated in a particular orientation, Therefore, it should not be construed as limiting the invention. Moreover, the terms "first", "second", "third", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be, for example, a fixed connection or a The connection is disassembled or connected in one piece; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the present invention can be understood as the case may be.

Embodiment 1

The method for reducing the back pressure fluctuation of the scroll compressor provided by the embodiment, extracting the high-pressure lubricating oil in the lubricating oil pool of the scroll compressor, and then depressurizing the high-pressure lubricating oil to form the medium-pressure lubricating oil, and then the medium pressure Lubricating oil is introduced into the back pressure chamber 2 of the scroll compressor to supply pressure to the back pressure chamber 2. The purpose is to establish a stable back pressure chamber 2 pressure, improve the reliability of the compressor operation and the tightness between the scrolls. Since the pressure of the high-pressure lubricating oil does not fluctuate during the operation of the compressor, the pressure of the back pressure chamber 2 established by the medium-pressure lubricating oil after the throttle reduction is also stable.

In this embodiment, the method specifically includes the following steps:

S1, a vane pump 7 is disposed at the bottom of the crankshaft 6 of the scroll compressor, and the vane pump 7 extracts the high-pressure lubricating oil in the lubricating oil pool connected thereto, and introduces the high-pressure lubricating oil into the movable scroll through the oil guiding hole 8 of the crankshaft 6. 13. The high pressure oil chamber 15 formed by the frame 9 and the crankshaft 6;

S2, an oil inlet passage 5 communicating with the high pressure chamber is disposed on the orbiting scroll 13 of the scroll compressor, and the high pressure lubricating oil in the high pressure oil chamber 15 is introduced into the oil inlet passage 5, and is in the oil inlet passage 5 The high pressure lubricating oil is depressurized to form a medium pressure lubricating oil;

S3, a through hole connecting the oil inlet passage 5 and the oil groove 12 of the movable scroll base plate 14 is disposed on the movable scroll 13, and the medium pressure lubricating oil is introduced into the back pressure chamber 2 communicating therewith through the oil groove 12 and passed through the medium pressure. The lubricating oil provides pressure to the back pressure chamber 2. Since the medium-pressure lubricating oil flows in the oil groove 12 of the mirror plate surface of the movable scroll 13, an oil film can be formed between the movable scroll 13 and the fixed scroll 1, and the movable scroll 13 and the static vortex are further improved. The tightness between the discs 1.

In step S2 of the present embodiment, the high pressure lubricating oil is depressurized by providing a throttle device in the oil inlet passage 5. In some examples, the throttle device is a throttle rod 4 disposed axially along the oil inlet passage 5, and the pressure reduction range of the high pressure lubricating oil can be adjusted by adjusting the cross-sectional area of the throttle rod 4. When it is required to greatly reduce the pressure of the high-pressure lubricating oil, the cross-sectional area of the throttle rod 4 can be increased, and the gap between the throttle rod 4 and the oil inlet passage 5 can be made small; when the pressure of the high-pressure lubricating oil is required to be small When the amplitude is lowered, the cross-sectional area of the throttle lever 4 can be reduced, and the gap between the throttle lever 4 and the oil inlet passage 5 can be made larger, thereby changing the pressure-reduction range of the high-pressure lubricating oil. It should be noted that, in addition to the throttle lever 4 provided in this embodiment, other throttling and pressure reducing structures conventionally used in the art, such as a throttle valve, are also included in the scope of protection of the present embodiment.

Embodiment 2

As shown in FIG. 1 , a scroll compressor provided in this embodiment includes a fixed scroll 1 , an orbiting scroll 13 , a frame 9 and a crankshaft 6 which are sequentially disposed from top to bottom, and a fixed scroll 1 Opposite the movable scroll 13, the frame 9 is for supporting the The scroll 1 is driven, the top of the crankshaft 6 passes through the axis of the frame 9 and is connected with the sliding bearing at the bottom of the movable scroll 13; the center of the frame 9 is provided with a cavity for rotating the sliding bearing, as shown in FIG. It is shown that the cavity constitutes a high-pressure oil chamber 15 communicating with the lubricating oil pool; the edge of the frame 9 is provided with a ring groove, and forms a back pressure chamber 2 with the fixed scroll 1.

As shown in FIGS. 3 and 4, an oil inlet passage 5 is formed in the radial direction of the movable scroll substrate 14, and the oil inlet passage 5 communicates with the high pressure oil chamber 15 and the back pressure chamber 2, wherein the oil inlet passage 5 passes through the first The oil hole 16 is connected to the high pressure oil chamber 15, and a throttle device is arranged in the oil inlet passage 5. The pressure in the back pressure chamber 2 of the scroll compressor is supplied to the medium-pressure lubricating oil formed by the high-pressure lubricating oil in the high-pressure oil chamber 15 by the throttle device. Since the pressure of the medium-pressure lubricating oil is stable, the medium-pressure lubricating oil introduced into the back pressure chamber 2 can supply a stable pressure to the back pressure chamber 2, and the pressure of the back pressure chamber 2 is kept constant, and the movable scroll 13 is prevented. The upper and lower sides fluctuate to avoid the phenomenon of internal leakage, and the sealing between the movable scroll 13 and the fixed scroll 1 is effectively improved.

The crankshaft 6 is provided with an oil guiding hole 8 in the axial direction, and a vane pump 7 is arranged at the bottom of the crankshaft 6. The vane pump 7 communicates with the lubricating oil pool. One end of the oil guiding hole 8 communicates with the high pressure oil chamber 15, and the other end communicates with the vane pump 7, through The vane pump 7 draws the high-pressure lubricating oil in the lubricating oil pool and conveys it into the accommodating chamber 10 and the high-pressure oil chamber 15 through the oil guiding hole 8.

The accommodating chamber 10 is defined in the bottom of the sliding bearing. The top end of the crankshaft 6 is inserted into the accommodating chamber 10, and the movable scroll 13 and the fixed scroll 1 are eccentrically disposed; the accommodating chamber 10 and the oil guiding hole 8 and the high pressure oil chamber 15 respectively The oil inlet passage 5 communicates with the oil guiding hole 8 as a high-pressure lubricating oil for the high-pressure oil chamber 15, and a transition space for the high-pressure lubricating oil in the high-pressure oil chamber 15 to be led out by the oil inlet passage 5.

The accommodating chamber 10 is disposed on the axis of the movable scroll 13, and the top of the crankshaft 6 is eccentrically provided with a connecting portion, and the connecting portion is inserted into the accommodating chamber 10 to ensure that the movable scroll 13 is eccentrically rotated with respect to the fixed scroll 1; The crankshaft 6 is connected to the driving motor, and the driving motor supplies power to the crankshaft 6, and drives the crankshaft 6 and the orbiting scroll 13 to rotate synchronously.

An annular oil groove 12 is disposed at the top of the movable scroll substrate 14, and an end of the oil inlet passage 5 near the edge of the movable scroll 13 communicates with the oil groove 12 through the second oil hole 3, and the oil groove 12 communicates with the back pressure chamber 2. The oil sump 12 can not only connect the oil inlet passage 5 with the back pressure chamber 2, but also establish a stable back pressure chamber 2 pressure by the high pressure lubricating oil. In addition, since the medium pressure lubricating oil flows in the oil tank 12, the movable scroll can also be used. An oil film is formed between the fixed scroll 1 and the stationary scroll 1 to further improve the sealing property between the movable scroll 13 and the fixed scroll 1.

The throttle device is a throttle rod 4 disposed axially along the oil inlet passage 5, and the pressure reduction range of the high pressure lubricating oil can be adjusted by adjusting the sectional area of the throttle rod 4. When it is required to greatly reduce the pressure of the high-pressure lubricating oil, the cross-sectional area of the throttle rod 4 can be increased, and the gap between the throttle rod 4 and the oil inlet passage 5 can be made small; when the pressure of the high-pressure lubricating oil is required to be small When the amplitude is lowered, the cross-sectional area of the throttle lever 4 can be reduced, and the gap between the throttle lever 4 and the oil inlet passage 5 can be made larger, thereby changing the pressure-reduction range of the high-pressure lubricating oil. It should be noted that, in addition to the throttle lever 4 provided in this embodiment, other throttling and pressure reducing structures conventionally used in the art, such as a throttle valve, are also included in the scope of protection of the present embodiment.

In addition, in the embodiment, the sealing ring 11 is disposed on the frame 9, the sealing ring 11 is opposite to the frame 9 and the movable scroll 13 The gap is sealed to ensure the tightness between the high pressure oil chamber 15 and the back pressure chamber 2.

The working principle of the scroll compressor of the present embodiment is that the high-pressure lubricating oil in the lubricating oil pool is sucked up by the vane pump 7, is introduced into the high-pressure oil chamber 15 through the oil guiding hole 8 of the crankshaft 6, and then is set in the moving vortex. The throttle rod 4 in the oil inlet passage 5 of the rotary disc substrate 14 is throttled and depressurized to reduce the pressure to form a medium-pressure lubricating oil, and is introduced into the second oil hole 3 on the movable scroll substrate 14 through the second oil. The hole 3 re-enters the oil groove 12 disposed on the movable scroll substrate 14. Since the oil groove 12 is in communication with the back pressure chamber 2, the medium pressure lubricating oil which has finally been lowered to the set pressure enters the back pressure chamber 2 , thereby forming the pressure of the back pressure chamber 2.

In summary, the present invention provides a method for reducing the back pressure fluctuation of a scroll compressor and a scroll compressor. The relationship between the rotation angle of the compressor and the pressure of the back pressure chamber 2 is shown in FIG. It can be seen that the pressure of the back pressure chamber 2 is a constant straight line. Therefore, the present invention solves the problem that the back pressure chamber 2 is unstable in pressure in the prior art, resulting in poor sealing between the movable scroll 13 and the fixed scroll 1 . problem.

The embodiments of the present invention have been presented for purposes of illustration and description, and are not intended to Many modifications and variations will be apparent to those skilled in the art. The embodiment was chosen and described in order to best explain the principles and embodiments of the invention,

Claims

A method for reducing back pressure fluctuation of a scroll compressor, characterized in that a high-pressure lubricating oil in a lubricating oil pool of a scroll compressor is extracted, and the high-pressure lubricating oil is depressurized to form a medium-pressure lubricating oil, and the middle The pressurized lubricating oil is introduced into the back pressure chamber of the scroll compressor to provide pressure to the back pressure chamber.
The method for reducing back pressure fluctuation of a scroll compressor according to claim 1, comprising the steps of:

S1, a vane pump is disposed at a bottom of a crankshaft of the scroll compressor, and the vane pump extracts high-pressure lubricating oil in the lubricating oil pool connected thereto, and introduces the high-pressure lubricating oil into the movable scroll through an oil guiding hole of the crankshaft. a high pressure oil chamber formed by a disk, a frame and a crankshaft;

S2, an oil inlet passage communicating with the high pressure chamber is disposed on an orbiting scroll of the scroll compressor, and high pressure lubricating oil in the high pressure oil chamber is introduced into the oil inlet passage, and The high pressure lubricating oil is depressurized in the oil inlet passage to form a medium pressure lubricating oil;

S3, a through hole connecting the oil inlet passage and the oil groove on the movable scroll substrate is disposed on the movable scroll, and the medium pressure lubricating oil is introduced into the back pressure chamber connected thereto through the oil groove and passes through the The medium pressure lubricating oil provides pressure to the back pressure chamber.
The method of reducing back pressure fluctuation of a scroll compressor according to claim 2, wherein in the step S2, a throttle device is disposed in the oil inlet passage, and the high pressure is applied by the throttle device Lubricating oil is reduced.
The method of reducing the back pressure fluctuation of a scroll compressor according to claim 2, wherein the throttle device is a throttle lever disposed along an axial direction of the oil inlet passage, and the throttle rod is adjusted by The cross-sectional area adjusts the pressure reduction range of the high-pressure lubricating oil.
A scroll compressor comprising: a fixed scroll, an orbiting scroll, a frame and a crankshaft disposed in order from top to bottom, wherein the fixed scroll is disposed opposite to the orbiting scroll, The frame is for supporting the orbiting scroll, the top of the crankshaft passes through the axis of the frame and is connected with a sliding bearing at the bottom of the movable scroll; the center of the frame is opened a cavity for facilitating rotation of the sliding bearing, the cavity forming a high pressure oil chamber communicating with the lubricating oil pool; an edge of the frame is provided with a ring groove, and a back pressure chamber is formed with the static scroll; An oil inlet passage is defined in a radial direction of the scroll disk substrate, and the oil inlet passage communicates with the high pressure oil chamber and the back pressure chamber, and the oil inlet passage is provided with a throttle device.
The scroll compressor according to claim 5, wherein the crankshaft is provided with an oil guiding hole in the axial direction, and a vane pump is provided at a bottom of the crankshaft, and the vane pump communicates with the lubricating oil pool. One end of the oil guiding hole communicates with the high pressure oil chamber, and the other end communicates with the vane pump.
The scroll compressor according to claim 6, wherein a bottom of the sliding bearing defines a receiving chamber, a top end of the crankshaft is inserted into the receiving chamber, and the movable scroll and the movable scroll are The fixed scroll is eccentrically disposed; the receiving chamber is respectively connected to the oil guiding hole, the high pressure oil chamber, and the oil inlet passage.
The scroll compressor according to claim 7, wherein the accommodating chamber is disposed at an axis of the orbiting scroll, and a top portion of the crankshaft is eccentrically provided with a connecting portion, and the connecting portion is interposed The crankshaft is connected to the driving motor, and the driving motor drives the crankshaft to drive the orbiting scroll to rotate synchronously.
The scroll compressor according to claim 7, wherein an annular oil groove is disposed at a top of the movable scroll substrate, and an end of the oil inlet passage adjacent to an edge of the movable scroll communicates with the oil groove. The oil sump communicates with the back pressure chamber.
The scroll compressor according to any one of claims 5-9, wherein the throttle device is a throttle lever disposed axially along the oil inlet passage.
A scroll compressor according to any one of claims 5 to 10, wherein the frame is provided with a seal ring for sealing the orbiting scroll and the frame.