CN212202465U

CN212202465U - Compression mechanism and scroll compressor

Info

Publication number: CN212202465U
Application number: CN202020500164.1U
Authority: CN
Inventors: 梁计; 赵平; 许美玲; 钱源
Original assignee: Emerson Climate Technologies Suzhou Co Ltd
Current assignee: Copeland Suzhou Co Ltd
Priority date: 2020-04-08
Filing date: 2020-04-08
Publication date: 2020-12-22
Anticipated expiration: 2030-04-08

Abstract

The utility model provides a compression mechanism and scroll compressor, this compression mechanism includes movable vortex and non-orbiting vortex, movable vortex includes movable vortex end plate and movable vortex blade, non-orbiting vortex includes non-orbiting vortex end plate, forms the non-orbiting vortex blade of the first side of non-orbiting vortex end plate, non-orbiting vortex and movable vortex cooperate in the operation process of compression mechanism in order to form a series of fluid cavities including central compression chamber, air suction chamber and the middle compression chamber between central compression chamber and air suction chamber; the second side of the fixed scroll end plate is provided with an exhaust communicating space, the fixed scroll end plate is provided with a pressure relief opening selectively in fluid communication with at least one intermediate compression cavity in the intermediate compression cavities and the exhaust communicating space, an exhaust groove communicated with the pressure relief opening is formed in the surface of the end plate on the first side of the fixed scroll end plate, and the pressure relief opening can be in fluid communication with the at least one intermediate compression cavity through the exhaust groove.

Description

Compression mechanism and scroll compressor

Technical Field

The utility model relates to a compression mechanism and scroll compressor. More particularly, the present invention relates to a scroll compressor having a variable volume ratio.

Background

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

The compressor may be applied to application systems requiring different pressures, such as an air conditioning system, a refrigerator system, a low-temperature refrigeration system, and the like, and thus, a case where a discharge pressure of a compression chamber (a maximum pressure in the compression chamber) is greater than a pressure required for a specific application system, that is, an over-compression case may occur. In the case of over-compression, the fluid compressed to the discharge pressure needs to be reduced to the pressure required by the application system after being discharged from the compression chamber. Therefore, compression work corresponding to a pressure difference between the discharge pressure of the compressor and the pressure required by the application system is wasted, resulting in a reduction in system efficiency.

In order to reduce or prevent over-compression of the working fluid, compressors with variable volume ratios have been developed. Such compressors may utilize a pressure relief orifice and a pressure relief valve assembly to achieve variable volume ratios. Specifically, a relief hole is provided in the non-orbiting scroll end plate, one end of the relief hole communicating with at least one compression chamber and the other end selectively fluidly communicating with an exhaust port of the compressor through an exhaust communication space surrounded by a non-orbiting scroll hub on the non-orbiting scroll end plate. When the pressure in the compression cavity reaches the required pressure, the pressure release valve is opened, the pressure release hole is communicated with the exhaust communication space, so that the fluid in the compression cavity is discharged in advance through the pressure release hole, and the fluid is prevented from being over-compressed. Therefore, the compressor with the variable volume ratio can realize that the compressor is operated at a low volume ratio when the pressure required by the system is low and the compressor is operated at a high volume ratio when the pressure required by the system is high, thereby effectively avoiding the over-compression phenomenon and improving the system efficiency.

However, in the compressor, since the position where the relief hole is provided is limited by the exhaust communication space, the position of the compression chamber where the relief hole can communicate is limited, and thus, the range of the variable volume ratio that can be realized by the relief hole is limited. In the case of a system requiring a low pressure, even if a pressure relief vent is used, there may still be an over-compression phenomenon.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to solve or alleviate foretell problem at least, provide a scroll compressor promptly, wherein the pressure release hole can communicate with the compression chamber that is close to compression mechanism's radial outside as far as possible for through the exhaust fluid pressure of pressure release hole reduce as far as possible, thereby alleviate or avoid the phenomenon of over-compression, improve system efficiency.

The utility model provides a compression mechanism, this compression mechanism including move the vortex and decide the vortex, move the vortex including moving the vortex end plate and forming at the vortex blade that moves of vortex end plate one side, decide the vortex including the deciding the vortex end plate that has first side and second side, form at the deciding the vortex blade of the first side of deciding the vortex end plate and form the central gas vent at deciding the vortex end plate center department, decide the vortex and move the vortex cooperation in compression mechanism's operation in-process and form a series of fluid cavitys therebetween, a series of fluid cavitys include the central compression chamber that communicates with central gas vent, with the suction chamber of the induction port intercommunication of compression mechanism and lie in the middle compression chamber between central compression chamber and the suction chamber; wherein, be provided with the exhaust intercommunication space in the second side of deciding the vortex end plate to be provided with the pressure release mouth that at least one intermediate compression chamber in the intermediate compression chamber of selective fluid intercommunication and exhaust intercommunication space in deciding the vortex end plate, wherein, be provided with the exhaust groove with pressure release mouth intercommunication in the end plate surface of deciding the vortex end plate's first side, the pressure release mouth can be through exhaust groove and at least one intermediate compression chamber fluid intercommunication.

Optionally, the vent slot extends outwardly from the pressure relief port generally in the direction of the scroll line of the non-orbiting scroll.

Alternatively, the discharge groove is provided to be exposed only to the intermediate compression chamber.

Optionally, the vent slot also extends inwardly from the pressure relief port generally in the direction of the scroll line of the non-orbiting scroll.

Alternatively, the discharge groove is disposed to be exposed to the central compression chamber and the intermediate compression chamber, and it should be noted that "capable of being exposed" herein is intended to mean that the discharge groove is exposed to both the central compression chamber and the intermediate compression chamber at some time of operation of the compressor or when the orbiting scroll moves to some position.

Optionally, when the discharge slot is exposed to both the central compression chamber and the intermediate compression chamber, the smaller of the area of the discharge slot exposed to the central compression chamber and the area of the discharge slot exposed to the intermediate compression chamber is less than or equal to 3% of the area of the central discharge port. Alternatively, the relief ports are arranged on both sides of the central exhaust port, one or more relief ports on each side, and the exhaust groove communicates with at least the relief port on the outermost side in the scroll line direction of the non-orbiting scroll for the relief port on each side.

Optionally, the minimum radial distance between the pressure relief port and/or the vent slot and the non-orbiting scroll blade is less than 80% of the radial thickness of the orbiting scroll blade.

Optionally, the radial width of the exhaust groove and/or the radial width of the pressure relief port is less than or equal to 1.1 times the radial thickness of the orbiting scroll blade.

Optionally, the discharge groove includes an innermost end and an outermost end in a scroll line direction of the non-orbiting scroll, and a radial width of the discharge groove is constant from the innermost end to the outermost end or gradually increases from the innermost end to the outermost end.

Alternatively, the cross section of the pressure relief opening in the radial direction is configured as a circle or a substantially long arc.

Alternatively, the pressure relief opening extends in an axial direction in a straight form in which the pressure relief opening is configured as a straight bore having one end in fluid communication with the at least one intermediate compression chamber and the other end in communication with the exhaust gas communication space, or in an offset form in which the pressure relief opening comprises a first section in fluid communication with the at least one intermediate compression chamber and a second section in communication with the exhaust gas communication space and the first section is offset radially outwards compared to the second section.

Optionally, the non-orbiting scroll further comprises a non-orbiting scroll hub formed on a second side of the non-orbiting scroll end plate, the non-orbiting scroll hub surrounding the central exhaust port to define an exhaust gas communication space.

The utility model also provides a scroll compressor, this scroll compressor above-mentioned compression mechanism.

Drawings

The features and advantages of one or more embodiments of the present invention will become more readily apparent from the following description taken in conjunction with the accompanying drawings. The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. The figures are not drawn to scale and some features may be exaggerated or minimized to show details of particular components. In the drawings:

fig. 1 is a longitudinal sectional view of a scroll compressor according to a comparative example;

FIG. 2 is a partially exploded schematic view of the scroll compressor of FIG. 1 showing a non-orbiting scroll having a variable volume ratio;

FIG. 3 is a bottom view of the non-orbiting scroll of FIG. 2 having a variable volume ratio;

FIG. 4 is a detail view of a portion of block A of FIG. 1 showing a biased pressure relief vent;

fig. 5a is a partial schematic view of a non-orbiting scroll of a scroll compressor according to a first embodiment of the present invention;

fig. 5b is a partial perspective view of a compression mechanism of a scroll compressor according to a first embodiment of the present invention;

fig. 6a is a partial schematic view of a non-orbiting scroll of a scroll compressor according to a second embodiment of the present invention;

fig. 6b is a partial perspective view of a compression mechanism of a scroll compressor according to a second embodiment of the present invention;

fig. 7a is a partial schematic view of a non-orbiting scroll of a scroll compressor according to a third embodiment of the present invention;

fig. 7b is a partial perspective view of a compression mechanism of a scroll compressor according to a third embodiment of the present invention;

fig. 8a and 8b are a bottom view of a non-orbiting scroll of a scroll compressor and a sectional view of a compression mechanism, respectively, according to a first modified example of the first embodiment of the present invention;

fig. 9 is a bottom view of a fixed scroll of a scroll compressor according to a second modified example of the first embodiment of the present invention;

FIG. 10 is a partial longitudinal cross-sectional view of a scroll compressor according to a first embodiment of the present invention showing a discharge slot;

fig. 11 is a graph showing the effect of comparison between the comparative example and the first and second embodiments of the present invention;

fig. 12 is a schematic bottom view of the non-orbiting scroll of the scroll compressor according to the first embodiment of the present invention, particularly illustrating the minimum distance h between the discharge groove and the non-orbiting scroll blade.

Detailed Description

Embodiments will now be described more fully with reference to the accompanying drawings.

The embodiments are provided so that this disclosure will be thorough and will more fully convey the scope to those skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods to provide a thorough understanding of embodiments of the present invention. It will be apparent to those skilled in the art that specific details need not be employed, that embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the invention. In some embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The general structure of the scroll compressor 100 is described below with reference to FIG. 1. As shown, the compressor 100 includes a housing 20, a compression mechanism, a motor, a rotary shaft, and the like. The housing 20 may be composed of a generally cylindrical body portion 22, a top cover 24 provided at one end of the body portion 22, and a bottom cover 26 provided at the other end of the body portion 22. A partition plate 30 is provided between the top cover 24 and the body part 22 to partition an inner space of the housing 20, wherein a space between the partition plate 30 and the top cover 24 constitutes the fluid discharge chamber 10, and a space between the partition plate 30, the body part 22 and the bottom cover 26 constitutes the fluid suction chamber 12. An intake joint for sucking fluid is provided at one side of the fluid suction chamber 12, and an exhaust joint for discharging compressed fluid is provided at one side of the fluid discharge chamber 10.

The compression mechanism includes a fixed scroll 40 and an orbiting scroll 50. The motor is configured to rotate the rotary shaft, which in turn drives the orbiting scroll 50 to orbit relative to the non-orbiting scroll 40 (i.e., the central axis of the orbiting scroll orbits the central axis of the non-orbiting scroll, but the orbiting scroll does not rotate about its central axis) to compress the working fluid.

Non-orbiting scroll 40 may include a non-orbiting scroll end plate 44 and a non-orbiting scroll blade 42 extending from a first side of non-orbiting scroll end plate 44. Orbiting scroll 50 may include an orbiting scroll end plate 54, and an orbiting scroll blade 52 formed at one side of orbiting scroll end plate 54. The non-orbiting and orbiting

scroll blades

42 and 52 are engageable with each other such that a series of fluid pockets (e.g., suction pocket C0, central compression pocket C1, intermediate compression pockets C2, C3) are formed between the non-orbiting and orbiting

scroll blades

42 and 52 when the scroll compressor is operating, thereby achieving compression of the working fluid. Specifically, referring to fig. 5b and 8b, of the fluid chambers, the radially outermost suction chamber C0 communicating with the suction port of the compression mechanism has the smallest pressure, the radially innermost fluid chamber, i.e., the central compression chamber C1 at the center of the scroll has the largest pressure, and a plurality of intermediate compression chambers (e.g., C2, C3) between the suction chamber C0 and the intermediate compression chamber C1 have intermediate pressures between the largest pressure and the smallest pressure.

To achieve compression of the fluid, an effective seal is required between the non-orbiting scroll 40 and the orbiting scroll 50. Referring to the non-orbiting scroll shown in fig. 2, typically, a back pressure chamber P is provided on a second side of the non-orbiting scroll end plate 44 opposite the first side to effect axial sealing between the tips of the non-orbiting scroll blades 42 and the orbiting scroll end plate 54 and between the tips of the orbiting scroll blades 52 and the non-orbiting scroll end plate 44. Non-orbiting scroll 40 includes a non-orbiting scroll hub 48 and an annular wall 43 extending from a second side of non-orbiting scroll end plate 44, with a central exhaust port 46 also formed substantially centrally of non-orbiting scroll end plate 44. Back pressure chamber P is formed by the space surrounded by non-orbiting scroll end plate 44, non-orbiting scroll hub 48, and annular wall 43 and is closed by a seal assembly disposed therein. Back pressure chamber P is in fluid communication with one of the intermediate pressure chambers of the compression chambers between orbiting scroll 50 and non-orbiting scroll 40 through an axially extending through hole formed in non-orbiting scroll end plate 44, thereby providing axial sealing pressure to non-orbiting scroll 40.

On the other hand, in order to avoid that the pressure of the fluid compressed by the central compression chamber C1 and discharged through the central discharge port 46 is greater than the pressure required by the system, i.e. in order to avoid the over-compression phenomenon of the scroll compressor 100, a relief port 47 (see fig. 2) communicating with at least one intermediate compression chamber (e.g. compression chamber C2 and/or C3) may be provided in the non-orbiting scroll end plate 44, so that the fluid in the intermediate compression chamber C2 and/or C3 which has not been compressed to the central compression chamber C1 can be discharged in advance through the relief port 47, thereby reducing the pressure of the discharged fluid of the scroll compressor.

The structure of the non-orbiting scroll provided with the pressure relief port 47 and the pressure relief valve assembly and the operation of the pressure relief port and the pressure relief valve assembly will be described with reference to fig. 2 and 3. The non-orbiting scroll hub 48 is disposed around the center exhaust port 46 to form an exhaust gas communication space S at the second side of the non-orbiting scroll end plate 44, which surrounds the center exhaust port 46 and can communicate with the center exhaust port 46. The discharge communication space S is spaced from the back pressure chamber P by the non-orbiting scroll boss 48. A relief port 47 is provided in the non-orbiting scroll end plate 44 in the exhaust communicating space S. The relief port 47 is a straight hole having a generally circular cross section in the radial direction and extending in a straight line form in the axial direction, and one end of the relief port 47 communicates with the exhaust communicating space S and the other end communicates with at least one intermediate compression chamber. Further, a relief valve is provided in the exhaust gas communication space S defined by the non-orbiting scroll boss 48. The relief valve includes a valve plate 61, a valve plate 62, a valve holder 63, a pin 64, and the like. The valve plate 61 is provided with through holes (two through holes are shown in fig. 2) at positions corresponding to the pressure relief ports 47. The valve plate 61 is provided with a valve sheet 62 to selectively open or close the through hole of the valve plate 61. The valve sheet 62 is provided with a valve holder 63. The pin 64 extends through pin holes formed in the valve plate 61, the valve sheet 62, and the valve holder 63 to fix the valve plate 61, the valve sheet 62, and the valve holder 63.

During the operation of the compressor 100, the working fluid is sucked into the compression mechanism and flows from the suction chamber C0 to the central compression chamber C1 to be gradually compressed, and the fluid after completion of compression is discharged through the central discharge port 46 communicating with the central compression chamber C1 and then discharged to the discharge chamber 10 via the check valve provided at the central position of the partition plate 30. In the event of over-compression, fluid may be prematurely vented to the communication region S through the pressure relief port 47 and the relief valve assembly before reaching the central compression chamber C1. Specifically, when the pressure of the fluid in the intermediate compression chamber (e.g., compression chambers C1 and/or C2) is greater than the pressure of the fluid in the discharge chamber 10 (i.e., over-compression occurs), the pressure on the lower side of the valve plate 62 is greater than the pressure on the upper side, and the valve plate 62 moves toward the open position under the pressure differential, thereby allowing early discharge of fluid through the relief port 47 and the through-holes in the valve plate 61. When the pressure of the fluid in the intermediate compression chamber (e.g., compression chamber C1 and/or C2) is lower than the pressure of the fluid in the discharge chamber 10, the valve sheet 62 returns to the closed position by the elastic restoring force and the pressure difference, thereby closing the relief port 47.

For scroll compressors having variable volume ratios, it is desirable to increase the range of variable volume ratios as much as possible to more effectively avoid over-compression phenomena. And the pressure relief port communicates with the compression chamber closer to the radially outermost side (i.e., the middle compression chamber closer to the suction chamber C0), the lower the discharge pressure discharged through the pressure relief port. Thus, to accommodate different system requirements for providing lower discharge pressures, the pressure relief port tends to be located as close to the radially outermost side of the compression mechanism as possible, moving toward the radially outermost side. However, as can be seen from the structure of the non-orbiting scroll shown in fig. 2 and 3, the relief port 47 is restricted in the communication area S defined by the non-orbiting scroll boss 48 due to the provision of the back pressure chamber P, and thus the distance that the relief port 47 moves toward the outermost side in the radial direction of the compressor hook is limited, resulting in a limited pressure difference of the fluid in the intermediate compression chamber, in which the relief port 47 can communicate, compared to the central compression chamber C1.

Fig. 4 shows a detailed view of a portion of block a in fig. 1. In order to communicate the relief port 47 with the intermediate compression chamber closer to the radially outermost side, as shown in fig. 4, the relief port 47 may be configured to include a first section 471 communicating with the intermediate compression chamber and a second section 472 selectively communicating with the discharge air communicating space S, the first section 471 communicating with the second section 472, and a central axis of the first section 471 being offset toward the radially outer side with respect to a central axis of the second section 472, thereby forming the offset relief port 47. This offset relief 47, which extends in an offset fashion, can communicate with the intermediate compression chamber closer to the radially outermost side, as compared to a relief extending axially in a straight fashion, so that the fluid pressure discharged through the relief 47 is lower, avoiding the over-compression phenomenon more effectively.

However, with such an offset relief port 47, the distance that the first section 471 is offset radially outward is limited due to the restriction of the orifice size.

The utility model provides a scroll compressor, including a new pressure relief vent design, this design makes the pressure relief vent can communicate with the middle compression chamber that is closer to the radial outside to reduce through pressure relief vent exhaust fluid pressure, avoid the phenomenon of overcompressing more effectively. An embodiment of the present invention will be described below with reference to fig. 5a to 9, wherein, except that the design regarding the pressure relief port is different from the scroll compressor 100 of the comparative example described above, the structure, operation manner, and the like of the scroll compressor are the same as the scroll compressor 100 of the comparative example described above, and thus will not be described again.

Fig. 5a shows a partial schematic view of a non-orbiting scroll of a scroll compressor according to a first embodiment of the present invention. As shown in fig. 5a, non-orbiting scroll 40 includes a non-orbiting scroll end plate 44 and a non-orbiting scroll blade 42, and a relief port 47 and a centrally located center discharge port 46 are provided in the non-orbiting scroll end plate 44. Wherein the relief ports 47 are disposed at both sides of the central exhaust port 46, and the number of the relief ports 47 at each side is three. Similar to the scroll compressor 100 of the comparative example shown in fig. 1 to 4, one end in the axial direction of each of the relief ports 47 on each side communicates with the discharge air communication region S on the second side of the non-orbiting scroll end plate 44, and the other ends in the axial direction of the innermost and intermediate relief ports in the scroll line direction of the non-orbiting scroll blades 42 in the relief ports 47 on each side directly communicate with the intermediate compression chamber. However, unlike the scroll compressor 100 of the comparative example, the other end in the axial direction of the relief port located on the outermost side in the scroll line direction of the fixed scroll blade 42 among the relief ports 47 on each side is connected to one discharge groove 141 and communicates with the intermediate compression chamber through the discharge groove 141. The discharge groove 141 is formed on the end plate surface of the first side of the non-orbiting scroll end plate 44 to extend from the end plate surface of the first side of the non-orbiting scroll end plate 44 to the second side, and has an extension depth as large as possible while securing the strength of the non-orbiting scroll end plate 44, so that more fluid enters the discharge groove 141, but the extension depth does not exceed the thickness of the non-orbiting scroll end plate 44 at maximum. In addition, the discharge groove 141 extends outward from the relief port 47 substantially in the scroll line direction of the fixed scroll 40, so that the discharge groove 141 can be exposed only to the intermediate compression chamber.

It should be noted that the number of the pressure relief ports 47 on each side may be one or other, and the pressure relief ports 47 may be formed in an axial straight hole shape or in an offset hole shape as shown in fig. 4 to add the effect of the air vent grooves 141. The air vent groove 141 may communicate not only with the pressure relief port located on the outermost side in the scroll line direction of the fixed scroll 40 among the pressure relief ports 47 on each side, but also with a plurality of pressure relief ports including the pressure relief port located on the outermost side in the scroll line direction of the fixed scroll 40 among the pressure relief ports 47 on each side or with all of the pressure relief ports 47.

During operation of the compressor, as shown in fig. 5b, as the orbiting scroll 50 moves around the non-orbiting scroll 40, the orbiting scroll blade 52 sometimes covers the relief port 47 and the discharge groove 141, sometimes exposing the relief port 47 and the discharge groove 141 to the intermediate compression chamber. Preferably, the minimum distance h (shown in fig. 12) between the pressure relief opening 47 and the air discharge groove 141 and the fixed scroll blade 42 is less than 80% of the radial thickness of the movable scroll blade 52, so that the movable scroll blade 52 can cover the pressure relief opening 47 and the air discharge groove 141 during the movement process, and the air discharge groove 141 is prevented from directly communicating two adjacent compression chambers to cause fluid leakage. Since the discharge groove 141 extends outward from the relief port 47, the discharge groove 141 can be exposed to the intermediate compression pockets earlier, that is, the discharge groove 141 can communicate with the intermediate compression pockets closer to the radially outermost side. The fluid in the intermediate compression chamber enters the relief port 47 through the vent groove 141 and is discharged to the communication region S. Compared with the comparative example in which the air discharge groove 141 is not provided (see fig. 1 to 4), the air discharge groove 141 plays a role of "moving" the air discharge port 47 toward the radial outside, so that the air discharge port 47 can communicate with the intermediate compression chamber closer to the radially outermost side through the air discharge groove 141, thereby discharging fluid of lower pressure to meet the system requirement.

On the other hand, referring to fig. 10, the radial width (diameter) of the relief port 47 and/or the radial width d of the vent groove 141 are generally kept constant. If the radial width (diameter) of the relief port 47 and/or the radial width d of the discharge groove 141 is too large, for example, far exceeds the thickness b of the orbiting scroll blade 52, the orbiting scroll blade 52 cannot always completely cover the relief port 47 and/or the discharge groove 141 during the operation of the compressor, and the adjacent two compression chambers (for example, the central compression chamber C1 and the intermediate compression chamber C2, or the central compression chamber C1 and the intermediate compression chamber C3) communicate through the relief port 47 and/or the discharge groove 141. For example, in the case where the relief valve is closed, the fluid in the higher pressure chamber (C1) of the adjacent two compression chambers leaks to the lower pressure chamber (C2 or C3) via the relief port 47 and/or the relief groove 141, resulting in repeated compression and a decrease in compressor efficiency. Therefore, it is preferable that the radial width (diameter) of the relief port 47 and/or the radial width d of the discharge groove 141 is 1.1 times or less of the thickness b of the orbiting scroll blade 52, so as to prevent fluid leakage between adjacent two compression chambers in the compressor. In addition, the length of the discharge groove 141 extending in the substantially scroll line direction of the non-orbiting scroll blade 42 is defined such that fluid cannot leak from the central compression chamber C1 to the intermediate compression chambers C2/C3 via the relief port 47 and the discharge groove 141 during operation of the compressor.

Fig. 6a shows a partial schematic view of a non-orbiting scroll of a scroll compressor according to a second embodiment of the present invention. Similar to the structure of the non-orbiting scroll according to the first embodiment of the present invention shown in fig. 5a and 5b, the non-orbiting scroll 40 includes a non-orbiting scroll end plate 44 and non-orbiting scroll blades 42, and a pressure relief port 47 and a centrally located central exhaust port 46 are provided in the non-orbiting scroll end plate 44. The structure, position and number of the pressure relief ports 47 are the same as those of the first embodiment, and therefore are not described again.

As shown in fig. 6a, the relief port 47 communicates with the intermediate compression chamber through a vent groove 241. The exhaust groove 241 is similar in position, thickness, width, and the like to the exhaust groove 141 of the first embodiment, except that the exhaust groove 241 is longer than the exhaust groove 141 in a length extending outward from the relief port 47 substantially in the scroll line direction of the fixed scroll 40.

It will be appreciated by those skilled in the art that the longer the outwardly extending length of the discharge slots, the closer to the radially outermost side the intermediate compression chambers are able to communicate, the lower the fluid pressure therein, and the better the effect of avoiding over-compression for scroll compressors of variable volume ratio. The discharge grooves 241 can be exposed to the intermediate compression chambers earlier than the discharge grooves 141, that is, the discharge grooves 241 can communicate with the intermediate compression chambers closer to the radially outermost side.

Of course, the long length of the discharge grooves may cause fluid leakage between the compression chambers. In the second embodiment, as shown in fig. 6b, the discharge groove 241 allows only a small amount of leakage to occur between the central compression chamber C1 and the intermediate compression chamber C2 and/or between the central compression chamber C1 and the intermediate compression chamber C3. But the effect of this small amount of leakage on the efficiency of the compressor is very slight, especially at part load conditions of the system. At a minimum, the discharge groove 241 cannot communicate with the suction chamber C0 to avoid fluid leakage from affecting the efficiency of the compressor.

The test effects of the comparative example, the first embodiment, and the second embodiment are described below with reference to fig. 11. An offset relief port is provided in the comparative example, an offset relief port and a shorter vent groove 141 are provided in the first embodiment, the shorter vent groove 141 having a length such that leakage does not occur between compression chambers at all, and an offset relief port and a longer vent groove 241 having a length such that only a small amount of leakage occurs between compression chambers are provided in the second embodiment. Other structures of the compressors in the comparative example, the first embodiment and the second embodiment are identical and operate under the same operating conditions.

The system operates within the envelope shown in fig. 11, and in the region above the scroll compression ratio line, the pressure required by the system is greater than or equal to the pressure provided by the compressor at full load (i.e., the pressure of the fluid discharged through the central compression chamber C1). In the region below the scroll compression ratio line, the pressure required by the system is less than the pressure provided by the compressor at full load, in which case the relief valve of a scroll compressor having a variable volume ratio will open and the lower pressure fluid in the intermediate compression chamber will be discharged through the relief port in advance, thereby reducing the discharge pressure of the compressor. The broken line shows a start line (hereinafter referred to as a relief valve activation start line of the comparative example) at which the relief valve of the scroll compressor in the comparative example opens and the relief port starts discharging fluid. The region between the scroll compression ratio line and the relief valve activation start line is referred to as region 1, and the region below the relief valve activation start line is referred to as region 2. In region 1, when the fluid pressure in the middle compression cavity reaches the pressure required by the system, the pressure relief port can be communicated with the middle compression cavity, and the fluid in the middle compression cavity can be discharged through the pressure relief port, so that the phenomenon of over-compression of the compressor can be completely avoided theoretically in region 1. In the region 2, when the fluid pressure in the intermediate compression chamber reaches the pressure required by the system, the relief port cannot be communicated with the intermediate compression chamber, but can be communicated with the intermediate compression chamber later, so that when the relief port is communicated with the intermediate compression chamber, the fluid pressure in the intermediate compression chamber exceeds the pressure required by the system, and thus the over-compression phenomenon is relieved but cannot be completely eliminated in the region 2.

In the first embodiment, the relief port 47 can communicate with the intermediate compression chamber earlier through the relief groove 141, and therefore the relief valve activation start line of the first embodiment is lowered compared to that of the comparative example, the area of the region 1 is increased, and the over-compression phenomenon is more favorably reduced or avoided. In the second embodiment, since the vent groove 241 is longer than the vent groove 141 and the relief port 47 can communicate with the intermediate compression chamber earlier through the vent groove 241, the relief valve activation start line of the second embodiment is lower than the relief valve activation start line of the first embodiment, the area of the region 1 is increased, and the over-compression phenomenon is more favorably reduced or avoided.

Taking condition 3 in fig. 11 as an example, in the comparative example, condition 3 is located within region 2. That is, the compressor in the comparative example may have an over-compression phenomenon when it operates in the operating condition 3. If the compressor in the first or second embodiment is employed, the over-compression phenomenon can be completely avoided in theory. The test results show that the first embodiment provides a significant efficiency improvement of about 1% and 2.5% for the conditions 3 and 4 of fig. 11, respectively, while the second embodiment provides an efficiency improvement of about 2.8% for the condition 4 of fig. 11.

Fig. 7a and 7b show a non-orbiting scroll of a scroll compressor according to a third embodiment of the present invention. Similar to the structure of the non-orbiting scroll according to the first embodiment of the present invention shown in fig. 5a and 5b, the non-orbiting scroll 40 includes a non-orbiting scroll end plate 44 and non-orbiting scroll blades 42, and a center exhaust port 46 located at the center in the non-orbiting scroll end plate 44. Unlike the first embodiment, the relief port 47 whose radial cross section is circular is no longer provided in the non-orbiting scroll end plate 44, but a relief port 47' whose radial cross section is substantially long arc-shaped is provided, and the relief ports 47' are arranged on both sides of the center exhaust port 46, the number of the relief ports 47' on each side being one. The pressure relief port 47' is axially configured in the form of a straight bore, or in a form similar to the offset pressure relief port 47. Similar to the first embodiment, one end of each relief port 47' in the axial direction communicates with the communication region S on the opposite side of the non-orbiting scroll 40 from the non-orbiting scroll blades 42, and the other end communicates with the discharge groove 341 and communicates with the intermediate compression chamber through the discharge groove 341. The discharge groove 341 extends outward from the relief port 47' in the scroll line direction of the non-orbiting scroll blade 42. The position, thickness, width, and the like of the exhaust groove 341 are similar to those of the exhaust groove 141 in the first embodiment.

Since the total area of the pressure relief ports 47 '(i.e., the pressure relief exhaust area) is increased compared to the total area of the one or more pressure relief ports 47, the amount of the working fluid of lower pressure discharged through the pressure relief ports 47' at the same time is increased, and thus the over-compression phenomenon can be more effectively avoided. In addition, as will be appreciated by those skilled in the art, the generally long arcuate shaped pressure relief port 47 'carries the risk of fluid leakage between the compression chambers as compared to the circular pressure relief port 47' as shown in fig. 5a and 5 b. Therefore, in the third embodiment, it is preferable that the length of the vent groove 341 extending outward from the relief port 47 'is set shorter than the vent groove 141 so that different compression chambers (e.g., between the central compression chamber C1 and the intermediate compression chamber C2 and/or between the central compression chamber C1 and the intermediate compression chamber C3) do not communicate with the vent groove 341 through the relief port 47', thereby preventing fluid leakage between the compression chambers.

In the third embodiment, although the air vent groove 341 is provided shorter than the air vent groove 141 of the first embodiment in order to avoid fluid leakage between the compression chambers, since the relief port 47' increases the relief air vent area so that more working fluid of lower pressure can be discharged, the effect of alleviating or avoiding the over-compression phenomenon of the third embodiment is substantially equivalent to that of the first embodiment.

It will be understood by those skilled in the art that the provision of the vent grooves is not limited to the

vent grooves

141, 241, 341 in the first to third embodiments described above, but allows any feasible modification and combination with the circular pressure relief port 47 or the substantially long arc-shaped pressure relief port 47'. For example, as a first modified example of the first embodiment shown in fig. 8a, taking the relief port 47 on either side of the central exhaust port 46 as an example, the exhaust groove 441 communicates with all of the three relief ports 47 on that side. Further, the exhaust groove 441 extends not only outward from the relief port 47 (the outermost relief port in the fixed scroll line direction) substantially in the scroll line direction of the fixed scroll 40 but also inward from the relief port 47 (the innermost relief port in the fixed scroll line direction) substantially in the scroll line direction of the fixed scroll 40, but the exhaust groove 441 is not connected to the center exhaust port 46. That is, in the first modified example, the exhaust groove 441 can be exposed not only to the intermediate compression chamber but also to the central compression chamber C1.

For the first modified example in fig. 8a, in the case where the inwardly extending portion of the discharge groove 441 is short, when the discharge groove 441 starts discharging gas when the orbiting scroll blade moves to a certain position, the inwardly extending portion of the discharge groove 441 does not communicate with the central discharge port 46, and the inwardly extending portion of the discharge groove 441 can increase the passage area of the relief port 47, reducing the discharge pressure loss; in the case where the inwardly extending portion of the discharge groove 441 is long, when the discharge groove 441 starts to discharge air while the orbiting scroll blade moves to a certain position, the inwardly extending portion of the discharge groove 441 communicates with the center discharge port 46, and if the compressor is operated at a low pressure ratio at this time, the discharge process is accelerated.

Referring to fig. 8b, during operation of the compressor, at some time or when the orbiting scroll 50 is rotated to some position, the discharge groove 441 is exposed to the central compression chamber C1 together with the central discharge port 46, the discharge groove 441 has an area 441a exposed to the central compression chamber C1 at the innermost end of the discharge groove 441 in the scroll-line direction, and the discharge groove 441 has an area 441b exposed to the intermediate compression chambers C2 or C3 at the outermost end of the discharge groove 441 in the scroll-line direction. The working fluid in the central compression chamber C1 can enter the discharge groove 441 and the relief port 47 from the area 441a and flow into the adjacent intermediate compression chamber C2 or C3 through the area 441b, so that fluid leakage occurs between the central compression chamber C1 and the intermediate compression chamber C2 or C3. In order to control the amount of fluid leakage while ensuring the effect of alleviating or avoiding the over-compression phenomenon, it is preferable that, when the discharge grooves 441 are exposed to the central compression chamber C1 together with the central discharge port 46, the smaller one of the area 441a at the innermost ends of the discharge grooves 441 and the area 441b at the outermost ends of the discharge grooves 441 is equal to or less than 3% of the area of the central discharge port 46.

In addition, as will be understood by those skilled in the art, with respect to the combination of the pressure relief vent 47 allowing a small amount of leakage and the longer vent groove 241 in the second embodiment, in order to control the amount of fluid leakage and ensure the effect of alleviating or avoiding the over-compression phenomenon, it is preferable that, when the pressure relief vent 47 is exposed to the central compression chamber C1 together with the central vent 46, the smaller one of the area of the pressure relief vent 47 exposed to the central compression chamber C1 and the area of the vent groove 241 exposed to the intermediate compression chambers C2/C3 is less than or equal to 3% of the area of the central vent 46. Similarly, with the combination of the relief port 47' and the shorter vent groove 341 in the third embodiment, it is also possible to set the vent groove 341 longer and allow a small amount of fluid leakage between the compression chambers. In order to control the amount of fluid leakage and to ensure the effect of alleviating or avoiding the over-compression phenomenon, the pressure relief port 47' and the vent groove 341 may be sized similarly to the first and second embodiments.

It should be noted that the discharge groove 541 can be exposed to the central compression chamber C1 and the intermediate compression chamber, and even extend in the entire intermediate compression chamber, but the discharge groove 541 cannot be exposed to the suction chamber C0, so that the compression chamber is prevented from communicating with the suction chamber C0 of the scroll mechanism through the discharge groove 541, and fluid leakage is prevented from affecting the efficiency of the compressor.

Fig. 9 shows a second modified example of the first embodiment. In the second modified example shown in fig. 9, the radial width d of the vent groove 641 is not constant but gradually increases from the innermost end toward the outermost end thereof in the scroll line direction of the non-orbiting scroll 40. That is, compared to the exhaust groove 441 in fig. 8a and 8b, the exhaust groove 641 has the smallest width at the innermost end in the scroll line direction of the fixed scroll 40, and the largest width at the outermost end of the exhaust groove 641 in the scroll line direction of the fixed scroll 40. Thus, in the event of fluid leakage between the compression chambers, the area of the discharge groove 541 at the innermost end exposed to the central compression chamber C1 is reduced, thereby further reducing the amount of fluid leakage between the compression chambers and improving the efficiency of the compressor, particularly under high load conditions.

Although various embodiments of the present invention have been described in detail herein, it is to be understood that the invention is not limited to the precise embodiments herein described and illustrated, and that other modifications and variations may be effected by one skilled in the art without departing from the spirit and scope of the invention. All such variations and modifications are intended to fall within the scope of the present invention. Moreover, all the components described herein may be replaced by other technically equivalent components.

Claims

1. A compression mechanism comprising:

the movable vortex comprises a movable vortex end plate and movable vortex blades formed on one side of the movable vortex end plate; and

a non-orbiting scroll including a non-orbiting scroll end plate having a first side and a second side, a non-orbiting scroll blade formed at the first side of the non-orbiting scroll end plate, and a central discharge port formed at a center of the non-orbiting scroll end plate, the non-orbiting scroll and the orbiting scroll cooperating to form a series of fluid chambers therebetween during operation of the compression mechanism, the series of fluid chambers including a central compression chamber communicating with the central discharge port, a suction chamber communicating with a suction port of the compression mechanism, and an intermediate compression chamber between the central compression chamber and the suction chamber;

wherein an exhaust communicating space is provided at a second side of the non-orbiting scroll end plate, and a pressure relief port selectively fluidly communicating at least one of the intermediate compression chambers with the exhaust communicating space is provided in the non-orbiting scroll end plate,

the fixed scroll compressor is characterized in that an exhaust groove communicated with the pressure relief port is formed in the surface of the end plate on the first side of the fixed scroll end plate, and the pressure relief port can be communicated with the at least one intermediate compression cavity through the exhaust groove.

2. The compression mechanism as claimed in claim 1, wherein said discharge groove extends outwardly from said discharge port generally in the direction of the scroll line of said non-orbiting scroll.

3. The compression mechanism as claimed in claim 2, wherein the discharge groove is provided to be exposed only to the intermediate compression chamber.

4. The compression mechanism as set forth in claim 2, wherein said discharge groove further extends inwardly from said discharge port generally in the direction of the scroll line of said non-orbiting scroll.

5. The compression mechanism as set forth in claim 4 wherein said discharge slots are disposed so as to be exposed to said central compression chamber and said intermediate compression chamber.

6. The compression mechanism of claim 5, wherein when the discharge slot is exposed to both the central compression chamber and the intermediate compression chamber, the smaller of the area of the discharge slot exposed to the central compression chamber and the area of the discharge slot exposed to the intermediate compression chamber is less than or equal to 3% of the area of the central discharge port.

7. The compression mechanism according to any one of claims 1 to 6, wherein the relief ports are arranged on both sides of the central discharge port, the relief port on each side being one or more, and the discharge groove communicates with at least the relief port on the outermost side in the scroll line direction of the non-orbiting scroll for the relief port on each side.

8. The compression mechanism as claimed in any one of claims 1 to 6, wherein the minimum radial distance between the relief port and/or the vent groove and the non-orbiting scroll blade is less than 80% of the radial thickness of the orbiting scroll blade.

9. The compression mechanism according to any one of claims 1 to 6, wherein a radial width of the discharge groove and/or a radial width of the relief port is equal to or less than 1.1 times a radial thickness of the orbiting scroll blade.

10. The compression mechanism according to any one of claims 1 to 6, wherein the discharge groove includes an innermost end and an outermost end in a scroll line direction of the non-orbiting scroll, and a radial width of the discharge groove is constant from the innermost end to the outermost end or gradually becomes larger from the innermost end to the outermost end.

11. The compression mechanism as claimed in any one of claims 1 to 6, wherein a cross section of the relief port in a radial direction is configured to be circular or substantially long arc.

12. The compression mechanism according to any one of claims 1 to 6, wherein the relief port extends in an axial direction in a straight form in which the relief port is configured as a straight hole having one end in fluid communication with the at least one intermediate compression chamber and the other end in communication with the exhaust gas communication space, or in an offset form in which the relief port includes a first section in fluid communication with the at least one intermediate compression chamber and a second section in communication with the exhaust gas communication space and the first section is offset toward a radially outer side than the second section.

13. The compression mechanism as recited in any one of claims 1 to 6, wherein the non-orbiting scroll further comprises a non-orbiting scroll hub formed on a second side of the non-orbiting scroll end plate, the non-orbiting scroll hub surrounding the central exhaust port to define the exhaust communication space.

14. A scroll compressor characterized by comprising a compression mechanism according to any one of claims 1 to 13.