WO2016026155A1

WO2016026155A1 - Rotary compressor

Info

Publication number: WO2016026155A1
Application number: PCT/CN2014/085055
Authority: WO
Inventors: 熊指挥; 郭宏; 黄锡槿
Original assignee: 广东美芝制冷设备有限公司
Priority date: 2014-08-22
Filing date: 2014-08-22
Publication date: 2016-02-25

Abstract

A rotary compressor (100) comprises a housing, a motor (2), and a compressing mechanism. The motor (2) is disposed in the housing. The housing comprises a lower housing assembly (12). The compressing mechanism is connected to the motor (2), and comprises an air cylinder (31), a main bearing (32), and an auxiliary bearing assembly (33). The auxiliary bearing assembly (33) comprises a hub portion (331) and a flange portion (332). The lateral size of the hub portion (331) is smaller than that of the flange portion (332). P1 and P2 separately satisfy: 0.1≤P1≤1.5 and 0.06≤P2≤1.1, wherein P1=H1/H2, P2=H3/H4, H1 indicates a vertical distance from the center of the lower surface of the hub portion (331) to the bottom wall of the lower housing assembly (12), H2 indicates the height of the auxiliary bearing assembly (33) in the vertical direction, H3 indicates a vertical distance from the edge of the lower surface of the flange portion (332) to the bottom wall of the lower housing assembly, and H4 indicates the height of the air cylinder (31) in the vertical direction.

Description

Rotary compressor

The present invention relates to the field of refrigeration equipment, and more particularly to a rotary compressor. Background technique

According to the related art, a part of the refrigerant compressed by the rotary compressor is dissolved in the refrigeration oil of the oil pool, which causes the viscosity of the refrigeration oil to be reduced, thereby reducing the lubrication condition of the moving parts in the rotary compressor, thereby reducing the lubrication condition. The reliability and working efficiency of the rotary compressor. Summary of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, an object of the present invention is to provide a rotary compressor capable of reducing the amount of refrigerant dissolved in the refrigerating machine oil in the oil pool, reducing the amount of refrigerant enclosed in the air conditioning system, and also ensuring the supply amount and supply of the rotary compressor. The quality of the oil improves the performance of the rotary compressor and improves the reliability of the rotary compressor.

A rotary compressor according to the present invention includes: a housing having an oil pool therein, the housing including a lower housing assembly; a motor, the motor being disposed in the housing; a compression mechanism, the compression a mechanism is coupled to the motor, the compression mechanism including a cylinder, a main bearing and a sub-bearing assembly, the main bearing and the sub-bearing assembly being respectively disposed at a top and a bottom of the cylinder and defining a compression chamber with the cylinder, The sub-bearing assembly includes a hub portion and a flange portion that are sequentially connected upward in the axial direction, and a lateral dimension of the hub portion is smaller than a lateral dimension of the flange portion, wherein P1 and P2 respectively satisfy: 0.1≤P1≤1.5, 0.06 <P2<1.1, where P1=H1/H2, P1=H3/H4, the HI is the vertical distance between the center of the lower surface of the hub portion and the bottom wall of the lower casing assembly, and the H2 is The height of the sub-bearing assembly in the up-and-down direction, the H3 is a vertical distance between the edge of the lower surface of the flange portion and the bottom wall of the lower casing assembly, and the H4 is the cylinder in the up and down direction The height above.

According to the rotary compressor of the present invention, the temperature in the oil pool is increased, so that the refrigerant content in the refrigerating machine oil dissolved in the oil pool is reduced, the refrigerant encapsulation amount in the air conditioning system is reduced, and the dissolution viscosity of the refrigerating machine oil is increased, and the increase is increased. The reliability of rotary compressors.

Optionally, the lower housing assembly has a downwardly projecting projection that is vertically opposed to the hub portion.

Or alternatively, the bottom surface of the lower housing assembly is formed as a flat surface.

Further, when the discharge volume of the compression chamber is less than or equal to 25 cm ³ / _rev , Pl and P2 are further satisfied: 0.1<P1<1.0, 0.08≤P2<0.8; When the discharge volume of the compression chamber is greater than 25 cm ³ /rev, Pl, P2 further satisfy: 0.1 < P1 < 1 0, 0, 06 ≤ P2 ≤ 0 + 4.

Optionally, the refrigerant used in the refrigeration cycle in the rotary compressor is a HC-based flammable refrigerant.

The additional aspects and advantages of the invention will be set forth in part in the description which follows. DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from

1 is a partial schematic view of a rotary compressor in accordance with an embodiment of the present invention;

Figure 2 is another schematic view of the rotary compressor shown in Figure 1;

3 is a diagram showing the relationship between the refrigerant content dissolved in the oil bath and the P1 and Ρ2 in the rotary compressor shown in FIG. 1. FIG. 4 is a diagram showing the relationship between the energy efficiency and the capacity of the system and P1 and Ρ2 according to an embodiment of the present invention. ;

Figure 5 is a diagram showing the relationship between the oil supply capacity of the crankshaft of the rotary compressor shown in Figure 1 and Ρ2;

Figure 6 is a graph showing the relationship between the coefficient of performance of the rotary compressor shown in Figure 1 and Ρ2;

Figure 7 is a graph showing the relationship between the refrigerant content, the system energy efficiency ratio, the oil supply capacity, and the coefficient of performance and the coefficient of performance of the rotary compressor in a rotary compressor according to an embodiment of the present invention. detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative only and not to limit the invention.

In the description of the present invention, it is to be understood that the terms "center", "lateral", "height", "thickness", "upper",

"Bottom", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Axial", "Radial", "Circumferential" The orientation or positional relationship of the instructions is based on the orientation or positional relationship shown in the drawings, and is merely for the convenience of the description of the invention and the simplified description, rather than indicating or implying that the device or component referred to has a specific orientation, The orientation and construction of the orientation are not to be construed as limiting the invention.

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 fixed or detachable, for example, unless otherwise explicitly defined and defined. Connected, or connected in one piece; can be directly connected, or indirectly connected through an intermediate medium, and can be internal to the two elements. The specific meanings of the above terms in the present invention can be understood in the specific circumstances by those skilled in the art. A rotary compressor 100 according to an embodiment of the present invention will be described below with reference to Figs.

As shown in Figs. 1 and 2, a rotary compressor 100 according to an embodiment of the present invention includes a housing, a motor 2, and a compression mechanism.

Referring to Figures 1 and 2, the housing is vertically arranged, wherein the central axis of the housing is perpendicular to its placement plane, the motor 2 and the compression mechanism are both disposed within the housing, and the motor 2 is coupled to the compression mechanism to drive the compression mechanism into the housing. The refrigerant in the compression chamber of the compression mechanism is compressed, and the bottom of the casing has an oil pool 13, and lubricating oil in the oil pool 13, such as refrigeration oil, can enter various moving parts of the compression mechanism to lubricate the respective moving parts.

It can be understood that the housing may include an upper housing, a main housing 11 and a lower housing assembly, and the main housing 11 may be generally formed into a cylindrical shape in which both the top and the bottom are open, and the upper housing and the lower housing assembly respectively Provided at the top and bottom of the main casing 11 together, the three together define an accommodation space for accommodating the above-described motor 2 and the compression mechanism. Of course, the specific structure of the housing can also be adapted according to the type of the rotary compressor 100, which is not particularly limited in the present invention. It is noted that the lower housing assembly of Figures 1 and 2 is the lower housing 12, however, when other components are mounted on the lower housing 12 and the components are located within the housing, that is, the lower housing assembly includes Lower housing 12 and the above components.

Specifically, as shown in FIGS. 1 and 2, the compression mechanism includes a cylinder 31, a main bearing 32, and a sub-bearing assembly, the top and the bottom of the cylinder 31 are open, and the main bearing 32 and the sub-bearing assembly are respectively disposed at the top of the cylinder 31. And the bottom portion, and the main bearing 32, the sub-bearing assembly and the cylinder 31 define a compression chamber, and the sub-bearing assembly includes a hub portion 33 1 and a flange portion 332 which are sequentially connected upward in the axial direction, and the hub portion 33 1 and the flange portion 332 are preferably The coaxial arrangement, wherein the lateral dimension of the hub portion 331 is smaller than the lateral dimension of the flange portion 332. Here, it is to be noted that the sub-bearing assembly in FIGS. 1 and 2 is the sub-bearing 33, however, when the vent hole is formed on the sub-bearing 33, a muffler may be disposed on the side of the sub-bearing 33 away from the cylinder. (not shown), in other words, the sub-bearing assembly includes a sub-bearing 33 and a muffler.

The present application is based on the discovery and recognition of the following facts and problems by the inventors: The inventors have found that the refrigerant (compressed as an oil and gas mixture) compressed in the compression chamber from the main bearing 32 when the rotary compressor 100 is in operation The vent hole is discharged, and at this time, the oil particles generated by the oil surface of the oil pool 13 are disturbed and splashed in the vicinity of the vent hole, and the refrigerant flows into the casing through the gap between the stator and the rotor of the motor 2 In the upper space, in the process, the refrigerating machine oil deposited by other factors such as the filter of the motor 2 is returned to the oil pool 13 at the bottom of the casing through the gap between the stator and the inner wall of the casing, and the remaining oil particles continue. Moving upwards together with the gaseous refrigerant through the exhaust port at the top of the housing, for example, entering the air conditioning system, and finally following the refrigerant together into the compression chamber through the suction port 31 of the housing for the next cycle. In the compressor, the refrigerating machine oil near the bottom of the oil pool 13 is pumped upward by the oiling blade in the center oil hole 341 of the crankshaft of the compression mechanism, and the respective moving parts of the compression mechanism are lubricated, and finally passed. The spiral oil groove provided on the main bearing 32 discharges the compression mechanism, and most of the refrigerator thereafter The oil flows downward toward the oil pool 13, and a small portion follows the refrigerant discharged from the compression chamber and flows upward.

In the above process, the refrigerating machine oil returning from the upper portion of the motor 2 is heated by the motor 2, and the temperature is high. The refrigerating machine oil flowing from the main bearing 32 for lubricating the moving parts is absorbed by a large amount of friction heat, and the temperature is also higher. high. These two parts of the higher temperature refrigerating machine oil flow down together to the oil pool 13, and heat transfer downward. The refrigerating machine oil in the lower part of the oil pool 13 exchanges heat with the outside of the casing through the casing, so that its own temperature is low.

Because the density of the refrigerating machine oil has a certain relationship with the temperature: the higher the temperature, the lower the density, so the refrigerating machine oil with higher temperature in the upper part of the oil pool 13 "floats" on the lower temperature of the refrigerating machine oil, when the higher temperature refrigerating machine oil When the temperature drops, this part of the refrigerating machine oil also sinks due to the increase in density. In the dynamic cycle of the entire oil circuit, the higher temperature refrigeration oil is always "floating" on the upper layer of the oil pool 13, and the low temperature refrigeration oil is always "deposited" in the lower portion of the oil pool 13. Thus, a refrigerating machine oil layer of different temperature gradients is formed in the longitudinal direction of the oil pool 13. This temperature difference of the refrigerating machine oil in the oil pool 13 is generally about 5 ° C to 10 ° C, or even larger.

Since the refrigerating machine oil in the compressor is compatible with the refrigerant, the amount of refrigerant dissolved in the refrigerating machine oil has a corresponding relationship with the pressure temperature: the higher the temperature, the smaller the solubility of the refrigerant, the viscosity of the refrigerating machine oil increases, and the reliability increases. That is, the lower the temperature, the greater the solubility of the refrigerant, and the lower the solubility viscosity of the refrigerating machine oil, so that the reliability of the rotary compressor 100 is lowered. Specifically, the refrigerating machine oil in the lower portion of the oil pool 13 is relatively low in temperature, so that the refrigerant discharged from the compression chamber is largely dissolved in the portion of the refrigerating machine oil, thereby reducing the efficiency of the rotary compressor 100, and because of the refrigerating machine oil The reduced solubility viscosity is unfavorable for lubrication between the moving parts of the compression mechanism, the friction loss is severe, the noise is large, and the service life of the rotary compressor 100 is lowered.

It can be seen that reducing the amount of refrigerant oil in the oil pool 13 in the rotary compressor 100 can reduce the amount of refrigerant dissolved in the refrigerating machine oil in the rotary compressor 100, thereby reducing the refrigerant in the air conditioning system. The amount of encapsulation, which is a flammable refrigerant with strict requirements for the amount of refrigerant enclosed, is extremely important.

Therefore, the crank oil suction portion (ie, the lower end of the crankshaft) is gathered to relatively high temperature of the refrigerating machine oil, thereby improving the dissolution viscosity of the refrigerating machine oil for lubrication, improving the lubrication state between the moving parts, thereby reducing refrigerant leakage and improving energy efficiency, and The reliability of the rotary compressor 100 can also be improved. This can be achieved by properly controlling the distance of the bottom of the compressor from the lower end of the crankshaft.

Specifically, as shown in FIG. 2, P1 and P2 respectively satisfy:

0.1 ≤ P1 ≤ 1.5, 0.06 < P2 < 1.1

Wherein P1=H1/H2, P2=H3/H4, HI is between the center of the lower surface of the hub portion 331 and the bottom wall of the lower casing assembly (for example, the bottom wall of the lower casing 12 in FIGS. 1 and 2) The vertical distance (i.e., the vertical distance between the center of the lower surface of the hub portion 331 and the projection of the center on the bottom wall of the housing), H2 is the sub-bearing assembly (e.g., the sub-bearing 33 of Figures 1 and 2) The height in the up and down direction, H3 is the edge of the lower surface of the flange portion 332 and the lower case group The vertical distance between the bottom wall of the piece (eg, the bottom wall of the lower case 12 in Figures 1 and 2) (i.e., between the edge of the lower surface of the flange portion 332 and the projection of the edge on the bottom wall of the housing) The vertical distance), H4 is the height of the cylinder 31 in the up and down direction (i.e., the thickness of the cylinder 31).

Referring to Fig. 2 and in conjunction with Figs. 3-7, by adjusting the distance relationship between the bottom wall of the casing and the sub-bearing 33, the cylinder 31, and the size of the sub-bearing 33 and the cylinder 31 itself, it is obtained through experiments. It is shown that the amount of refrigerant dissolved in the refrigerating machine oil increases as the values of P1 and P2 increase. In other words, when P1 and P2 are small, the amount of refrigerant dissolved in the refrigerating machine oil is small, for example, when the height of the sub-bearing 33 and the cylinder 31 is high. When not changing, the distance H1 between the lower surface of the hub portion 331 of the sub-bearing 33 and the bottom wall of the housing should be minimized, and the edge of the lower surface of the flange portion 332 of the sub-bearing 33 and the bottom wall of the housing should be minimized. The vertical distance between the two is H3.

Preferably, as shown in FIGS. 2 and 3, the lower casing 12 includes a boss portion and a connecting portion, and the boss portion may be formed to protrude downward from the center of the lower casing 12, and the connecting portion is connected to the boss portion. On the outer circumference, the plane in which the connecting portion is located is higher than the bottom surface of the boss portion, and the boss portion is vertically opposed to the hub portion 331, at which time HI is the vertical between the center of the lower surface of the hub portion 331 and the bottom wall of the boss portion. The distance H3 is the vertical distance between the edge of the lower surface of the flange portion 332 and the upper surface of the connecting portion. Of course, the invention is not limited thereto, and the bottom surface of the lower casing 12 may also be formed in a plane.

Further, it can be seen from FIG. 3 that when P1 and P2 are small, the amount of refrigerant dissolved in the refrigerating machine oil is not increased greatly, and when P1 and P2 are increased to a certain value, the amount of refrigerant dissolved in the refrigerating machine oil is small. The increase is larger.

In the air conditioning system, the change in the amount of refrigerant enclosed is similar to the above change. In the case of ensuring that the amount of refrigerant enclosed in the system is constant, the energy efficiency ratio (EER) is the coefficient of cooling performance of the air conditioner, also known as the energy efficiency ratio, which represents the unit power cooling capacity of the air conditioning system. The higher the EER value, the air conditioner. The system absorbs more heat in the system or consumes less electricity from the compressor.) The ability to change with Pl and P2 is shown in Figure 4. As can be seen from the figure, when P1 and P2 are large, the rotary type The amount of refrigerant dissolved in the compressor oil in the compressor 100 is increased, the amount of refrigerant used in the refrigeration cycle in the system is reduced, the system capacity is decreased, and the energy efficiency of the air conditioning system is also affected, in contrast, when Pl, P2 are small, The system has high energy efficiency and capability.

Inside the casing, since the lower end surface of the crankshaft and the lower end surface of the sub-bearing 33 (i.e., the lower end surface of the hub portion 331) are generally substantially flush, the distance between the lower end of the crankshaft and the bottom wall of the casing is substantially equal to the above-described distance H1, This distance will directly affect the oil supply capacity and quality of the crankshaft. For example, if the distance HI is too small, due to the disturbance of the rotation of the oiling blade, the refrigeration oil at the lower end of the center oil hole 341 may have foam, the quality of the oil supply may be affected, and the oil supply amount may have a relatively large influence. Further, in the rotary compressor 100, since the constraints on the structure, design, and the like determine the requirements for the oil supply capacity, it is also necessary to consider the influence of these factors on the oil supply capability. As shown in Figure 5, with the increase of P2, the oil supply capacity of the crankshaft is improved first and then stabilized. When the oil supply capacity is greater than 2, The lubrication can be effectively ensured to ensure the reliability of the rotary compressor 100. Therefore, from the viewpoint of the reliability of the rotary compressor 100, the value of P2 must be larger than a certain value, that is, in the case where the thickness of the cylinder 31 remains unchanged, The vertical distance between the edge of the lower surface of the flange portion 332 of the bearing 33 and the bottom wall of the housing may not be too close. Here, it should be noted that "1st grade", "2 grade" and "3 grade" in FIG. 5 may indicate that the oil supply amount of the crankshaft is 10 ml/min, 20 ml/min, 50 ml/min, respectively, of course, the present invention The present invention is not limited thereto, and the oil supply level of the crankshaft may be specifically divided according to actual requirements.

Since P2 has a certain relationship with the oil supply capacity of the rotary compressor 100, when the oil supply capacity is small, the refrigeration oil between the moving parts is insufficient, the lubrication and the sealing are deteriorated, and the leakage of the refrigerant between the matching parts is increased, between the friction pairs. The coefficient of friction increases and the resistance increases, resulting in a decrease in the COP (Coefficient of Performance) of the entire rotary compressor 100. The relationship between COP and P2 of the rotary compressor 100 is as shown in Fig. 6. As can be seen from the figure, the relationship between the COP and P2 of the rotary compressor 100 is related to the oil supply capacity of the crankshaft and P2. The relationship is roughly the same, that is, it is improved first and then stabilized.

In combination with the above influencing factors, the values of P1 and P2 and the refrigerant content dissolved in the refrigerating machine oil, the oil supply capacity of the rotary compressor 100, the COP of the rotary compressor 100, the system refrigerant entrapment amount, and the system energy efficiency can be known. There is a close relationship, as shown in Figure 7 (only the trend relationship is shown in the figure), and the relationship between the various influencing factors is integrated to obtain the optimal Pl, P2 value range, ie 0.1 ≤ P1 ≤ 1.5, 0.06 < P2 < 1.1„

Thus, by properly designing the bottom of the casing, such as the lower casing 12, the refrigeration oil content of the refrigeration oil in the oil pool 13 in the rotary compressor 100 is changed, thereby reducing the amount of refrigerant dissolved in the refrigeration oil, thereby reducing the system. The amount of refrigerant enclosed. By properly designing the lower casing 12, the quality of the oil supply and the refrigerating machine oil can be better improved, the lubrication can be improved, and the energy efficiency and reliability of the rotary compressor 100 can be improved.

Further, when other components are mounted on at least one of the bottom of the casing, that is, the lower casing 12 or the lower portion of the sub-bearing 33, for example, when the exhaust hole is provided on the sub-bearing 33, the sub-bearing 33 may be away from the cylinder 31. One side is provided with a muffler, and H3 is the vertical distance between the muffler and the bottom of the housing. It can be understood that the specific position of the components disposed on the lower casing 12 and the sub-bearings 33 can be specifically designed according to actual requirements. Accordingly, the specific dimensions of HI to H4 can be specifically determined according to the above definition, and details are not described herein again.

According to the rotary compressor 100 of the embodiment of the present invention, the temperature in the oil pool 13 is increased, so that the refrigerant content in the refrigerating machine oil dissolved in the oil pool is reduced, and the refrigerant encapsulation amount in the air conditioning system is reduced (that is, the same refrigerant encapsulation amount is reduced). The energy efficiency of the system is improved, and the dissolution viscosity of the refrigerating machine oil is increased, and the reliability of the rotary compressor 100 is increased.

Further, when the discharge volume of the compression chamber is less than or equal to 25 cm ³ / _rev (that is, each time the piston of the compression mechanism rotates one turn, the discharged cold medium product is less than or equal to 25 cm ³ ), Pl, P2 further satisfy - 0.1<P1<1.0, 0.08<P2<0.8;

When the discharge volume of the compression chamber is greater than 25 cm ³ / _rev (that is, every time the piston of the compression mechanism rotates, the discharged cold medium product is greater than 25 cm ³ ), Pl and P2 are further satisfied:

0.1 < P1 < 1.0, 0.06 ≤ P2 ≤ 0.4.

Here, it is to be noted that the "discharge volume of the compression chamber" means that the inner end of the slide of the compression mechanism abuts against the piston in the compression chamber, and the slide is completely housed in the slide groove of the cylinder 31, and is compressed. The volume of the space defined between the inner peripheral wall of the inner cylinder 31 and the outer peripheral wall of the piston. It will be understood that the direction "inside" refers to the direction toward the center of the cylinder 31. Among them, since the slider, the slider slot and the like are well known to those skilled in the art, they will not be described in detail herein.

Thus, when the discharge volume of the compression chamber is large (i.e., greater than 25 cm ³ / _rev ), by designing P2 to a smaller range, for example, when the height of the cylinder 31 remains unchanged, the lower casing 12 is When the bottom wall is closer to the flange portion 332, the temperature of the refrigerating machine oil in the oil pool is higher, which can further reduce the amount of refrigerant dissolved in the refrigerating machine oil in the rotary compressor 100, reduce the amount of refrigerant enclosed in the air conditioning system, and ensure rotation. The compressor 100 is supplied with oil and oil quality, so that the performance of the rotary compressor 100 can be further improved, and the reliability of the rotary compressor 100 can be improved.

Alternatively, the refrigerant for the refrigeration cycle in the rotary compressor 100 is flammable, and may be, for example, a HC-based flammable refrigerant, but is not limited thereto. Here, it should be noted that HC-type flammable refrigerants are well known to those skilled in the art and will not be described in detail herein.

According to the rotary compressor 100 of the embodiment of the present invention, the above object can be well achieved by designing a reasonable size of the bottom of the casing and the size of the rotary compressor 100. Through the relevant design and test verification, reasonable numerical ranges of Hl, H2, H3 and H4 are obtained, so that less refrigerant is dissolved in the refrigerator oil in the casing, and the oil supply capacity of the rotary compressor 100 is ensured and the reliability is improved. The air conditioning system has a small amount of refrigerant enclosed and improved energy efficiency.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples", etc. Particular features, structures, materials or features described in the examples or examples are included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms does not necessarily mean the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

While the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art The scope of the invention is defined by the claims and their equivalents.

Claims

Claim

A rotary compressor, comprising:

a housing having an oil pool therein, the housing including a lower housing assembly;

a motor, the motor being disposed in the housing;

a compression mechanism, the compression mechanism being coupled to the motor, the compression mechanism including a cylinder, a main bearing and a sub-bearing assembly, the main bearing and the sub-bearing assembly being respectively disposed at a top and a bottom of the cylinder and with the cylinder Defining a compression chamber, the sub-bearing assembly includes a hub portion and a flange portion that are sequentially connected upward in the axial direction, the lateral dimension of the hub portion being smaller than a lateral dimension of the flange portion, wherein P1, P2 respectively satisfy:

0.1 ≤ P1 < 1.5, 0.06 < P2 < 1.1

Wherein, P1=H1/H2, P2=H3/H4, the HI is a vertical distance between a center of a lower surface of the hub portion and a bottom wall of the lower casing assembly, and the H2 is the sub-bearing assembly The height in the up and down direction, the H3 is a vertical distance between the edge of the lower surface of the flange portion and the bottom wall of the lower casing assembly, and the H4 is the height of the cylinder in the up and down direction.

The rotary compressor according to claim 1, wherein the lower casing assembly has a convex portion that protrudes downward, and the convex portion is opposed to the boss portion.

The rotary compressor according to claim 1, wherein a bottom surface of the lower casing assembly is formed into a flat surface.

The rotary compressor according to any one of claims 1 to 3, wherein, when the discharge volume of the compression chamber is less than or equal to 25 cm ³ /rev, P1, P2 are further satisfied:

0.1 ≤ P1 ≤ 1.0, 0.08 < P2 < 0.8;

When the discharge volume of the compression chamber is greater than 25 cm ³ /rev, Pl, P2 further satisfy:

0.1 < P1 < 1.0, 0.06 ≤ P2 ≤ 0.4.

The rotary compressor according to claim 1, wherein the refrigerant for the refrigeration cycle in the rotary compressor is a HC-based flammable refrigerant.