EP2924292A2

EP2924292A2 - Rotary compressor

Info

Publication number: EP2924292A2
Application number: EP15159760.6A
Authority: EP
Inventors: Makoto Ogawa; Shigeki Miura; Ikuo Esaki; Masanari Uno; Yuichi Muroi
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Ltd
Priority date: 2014-03-25
Filing date: 2015-03-19
Publication date: 2015-09-30
Anticipated expiration: 2035-03-19
Also published as: JP6396050B2; JP2015183613A; EP2924292A3; EP2924292B1

Abstract

A rotary compressor includes: a cylinder main body (11) that forms a cylinder chamber (10); a rotor (14) fitted onto an eccentric part (9a) of a rotating shaft (9), orbits in the cylinder chamber (10) in accordance with rotation of the rotating shaft, and whose outer circumferential surface (14a) is brought into sliding contact with an inner circumferential surface; and a blade (17) whose front end portion (17a) is brought into contact with the outer circumferential surface (14a) of the rotor and that slides in a blade groove (15) provided in the cylinder main body in accordance with orbiting of the rotor. The blade (17) has a hollow portion (171) therein that allows the blade to be bent in a thickness direction thereof, and the hollow portion is open to a rear end portion (17b) and both side portions of the blade.

Description

{Technical Field}

The present invention relates to a rotary compressor that is used to compress refrigerant gas etc.

{Background Art}

A rotary compressor has a rotor that rotates along an inner circumference of a cylinder chamber due to rotation of a rotating shaft and also includes a blade (vane) whose front end is brought into contact with an outer circumferential surface of the rotor to partition the inside of the cylinder chamber into a suction side and a compression side and that reciprocates in a radial direction in a blade groove provided in a cylinder main body, in accordance with rotation of the rotor. During compression operation, the blade reciprocates in the blade groove at a certain sliding speed while being subjected to a contact pressure caused by a pressure difference between the suction side and the compression side, the contact pressure occurs between the blade and side surfaces of the blade groove.
Regarding the contact between the side surfaces of the blade and the side surfaces of the blade groove, which is provided in the cylinder main body, the entire side surfaces of the blade are not subjected to force of the contact pressure evenly over the entire side surfaces of the blade groove, and the blade is subjected to the above-described pressure difference and slides while being tilted by an amount depending on a gap of the sliding portion between the blade and the blade groove. Thus, as shown in PTL 1, partial contact is caused. Specifically, the blade is subjected to force concentrated on a line due to partial contact, and the positions of said force move along the surface of the blade within the blade reciprocation range.
Although the sliding surfaces of the blade and the blade groove are lubricated by supplying lubricant oil that is mixed in fluid as refrigerant gas and the like, after long-term usage, oil film breakdown occurs due to the partial contact, thus causing wear to progress and causing rotor seizure, in some cases. Such events cause a reduction in reliability with respect to the life of a compressor, a reduction in compression performance due to an increase in gas leakage, etc. Thus, PTL 1 discloses a technology in which concavo-convex-shaped fine grooves for holding oil are provided on both side surfaces of the blade closer to a front end and both side surfaces thereof closer to a rear end. Furthermore, PTL 2 discloses a technology in which fine concave portions (dimples) having appropriate opening area ratio, surface roughness, and depth are provided at portions where partial contact is likely to occur and portions where surface pressure is relatively high, in either the blade or the blade groove, or both.

{Citation List}

{Patent Literature}

{PTL 1} Japanese Unexamined Patent Application, Publication No. S63-189683
{PTL 2} Japanese Unexamined Patent Application, Publication No. 2011-21597

{Summary of Invention}

{Technical Problem}

As shown in PTL 1 or 2, the concavo-convex-shaped fine grooves or the fine concave portions (dimples) are provided at portions where partial contact is likely to occur and at portions where surface pressure is relatively high, to hold oil using those grooves or dimples, thereby making it possible to prevent oil film breakdown and to expect a prevention effect on abnormal wear and compressor seizure. However, in the technologies disclosed in PTLs 1 and 2, the fine grooves and the dimples are not necessarily provided in only truly-required ranges. Although those fine grooves and dimples are effective in preventing abnormal wear and compressor seizure, they also constitute gas leakage pathways.
Therefore, if the area in which the fine grooves or the dimples are provided is increased more than its truly required area by focusing too much on the prevention of abnormal wear and compressor seizure, an increase in gas leakage could cause a reduction in compression efficiency. In particular, increasing the degree of eccentricity of a rotor can be considered as a means to increase displacement (capacity) of a compressor. However, in this case, the PV value of blade side surfaces (the product of the contact pressure P between the blade side surfaces and the blade-groove side surfaces and the blade sliding speed V (P×V)) is increased, so that the blade is likely to be seized. As a measure against this, it becomes more important to provide fine grooves or dimples for holding oil. However, increasing the area in which the fine grooves or the dimples are provided means an increase in the gas leakage gap, which leads to a reduction in efficiency caused by an increase in leakage loss.
Furthermore, if the area in which the fine grooves or the dimples are provided is increased too much from the aspect of preventing abnormal wear and compressor seizure, as described in PTL 1 or 2, when the degree of parallelism of the blade side surfaces is measured, the measurement needs to be performed in a narrow area where fine concave portions etc. are not provided, thereby making it impossible to perform precise parallelism measurement, which could affect the function and the performance of the blade.
The present invention is made in view of such circumstances, and an object thereof is to provide a rotary compressor that is capable of enhancing the reliability by preventing wear, compressor seizure, etc. of the blade and that is capable of achieving enhanced compression efficiency by reducing leakage of compressed fluid from a gap of a sliding portion between the blade and the blade groove.

{Solution to Problem}

In order to make an improvement in the above-described circumstances, a rotary compressor of the present invention adopts the following solutions.
Specifically, a first aspect of of the rotary compressor according to the present invention includes: a cylinder main body that forms a cylinder chamber; a rotor that is fitted onto an eccentric part of a rotating shaft, that orbits in the cylinder chamber in accordance with rotation of the rotating shaft, and whose outer circumferential surface is brought into sliding contact with an inner circumferential surface of the cylinder chamber; and a blade in which a front end portion is brought into contact with the outer circumferential surface of the rotor to partition the inside of the cylinder chamber into a suction side and a compression side, the blade being configured to slide in a groove provided in the cylinder main body so as to be extended from and retracted into the groove in accordance with orbiting of the rotor, wherein the blade has a hollow portion therein that allows the blade to be bent in a thickness direction thereof; and the hollow portion is open to the outside of the blade at a rear end portion and both side portions of the blade.
In the above-described configuration, the blade inserted into the blade groove of the cylinder main body comes out from the blade groove in accordance with orbiting of the rotor, and the front end portion of the blade is brought into contact with the outer circumferential surface of the rotor to partition the space in the cylinder chamber into the suction side and the compression side, thus performing the compression operation.
At this time, because the blade is subjected to a contact pressure due to the pressure difference between the suction side and the compression side, the blade slides while being tilted toward the suction side by an amount in accordance with a gap of the sliding portion between the blade and the blade groove. At the same time, the blade is bent slightly toward the suction side due to the hollow portion formed in the blade.
When the blade is bent toward the suction side in this way, contact areas at portions where the side surfaces of the blade are brought into partial contact with the blade groove are increased, which means that those portions are brought into surface contact with the blade groove, thus reducing a PV value. Therefore, an oil film is less likely to breakdown at contact portions between the blade and the blade groove, thus preventing wear from progressing and compressor seizure from occurring at the contact portions, and enhancing the reliability of the rotary compressor.
Furthermore, when compressed fluid flows from a gap of a sliding portion between the blade and the blade groove into the hollow portion in the blade, the pressure of the fluid brings both surfaces of the blade into contact with inner surfaces of the blade groove through elastic deformation. Accordingly, the gap becomes small, thus improving the sealability, and leakage of the compressed fluid from a high-pressure side (the compression side) to a low-pressure side (the suction side) can be reduced (gas leakage loss can be reduced), thus enhancing the compression efficiency of the rotary compressor.
In the above-described configuration, it is desirable that the hollow portion be formed from the rear end to a vicinity of a front end portion of the blade.
By forming the hollow portion from the rear end to the front end portion of the blade in this way, the thickness of the front end portion of the blade is reduced, and the blade front end portion is softened and is brought into contact with the outer circumferential surface of the rotor in a wide area. Accordingly, it is possible to reduce the contact surface pressure at the front end portion of the blade, which prevents breakdown of an oil film, wear, and compressor seizure, thus enhancing the reliability of the rotary compressor.
In the above-described configuration, it is preferable that the hollow portion is formed from the rear end and at least to a position which is located at a front end side relative to a rear end position of the blade at which the blade protrudes from the blade groove into the cylinder chamber when the blade is fully extended.
By forming the hollow portion from the rear end to the above-described position, it is possible to reduce the machining cost, compared with the case in which the hollow portion is formed from the rear end to the vicinity of the front end portion of the blade.
Furthermore, a portion of the blade closer to the rear end portion is hollowed, a portion of the blade closer to the front end portion is made solid, and the length of the hollow portion is adjustable, thereby making it possible to adjust the amount of bending of the blade in accordance with the characteristics of the rotary compressor.
In the above-described configuration, the hollow portion may be provided with a through-hole that penetrates the blade in a vicinity of a front end portion along the axial direction of the rotating shaft and a slit that is formed so as to extend from the rear end portion of the blade to the through-hole and that has an inner width narrower than an inner diameter of the through-hole.
With the above-described configuration, it is possible to make the thickness in the vicinity of the front end portion of the blade thinner than the thicknesses of intermediate and other portions of the blade and to soften the front end portion of the blade to bring it into contact with the outer circumferential surface of the rotor in a wide area, thus reducing surface pressure, which prevents breakdown of an oil film, wear, and compressor seizure of the blade, and enhancing the reliability of the rotary compressor.
In the above-described configuration, a maximum width of the blade at the rear end portion may be set larger than an inner width of the blade groove such that both surfaces of the blade are brought into contact with inner surfaces of the blade groove in a lightly elastically deformed state.
By doing so, a gap of the sliding portion between the blade and the blade groove becomes very small, thus making compressed fluid less likely to leak from the gap. Accordingly, it is possible to reduce leakage of compressed fluid from a high-pressure side to a low-pressure side (gas leakage loss), and to enhance the compression efficiency of the rotary compressor.

{Advantageous Effects of Invention}

As described above, according to the rotary compressor of the present invention, it is possible to reduce the PV value (the product of the contact pressure P and the blade sliding speed V) acting on the side surfaces and the front end portion of the blade during the compression operation, which prevents wear, compressor seizure, etc. of the blade and enhances the reliability, and to reduce leakage of compressed fluid from a gap of the sliding portion between the blade and the blade groove, thus achieving enhanced compression efficiency.

{Brief Description of Drawings}

{Fig. 1} Fig. 1 is a longitudinal sectional view showing an example rotary compressor to which the present invention can be applied.
{Fig. 2} Fig. 2 is a transverse sectional view showing a compression mechanism portion of the rotary compressor, along the line II-II of Fig. 1.
{Fig. 3} Fig. 3 is a view schematically showing the behavior of a blade during compression operation of the rotary compressor.
{Fig. 4} Fig. 4 is a plan view showing the vicinity of a blade according to a first embodiment of the present invention.
{Fig. 5} Fig. 5 is a plan view showing a function of the blade shown in Fig. 4.
{Fig. 6} Fig. 6 is a plan view showing the vicinity of a blade according to a second embodiment of the present invention.
{Fig. 7} Fig. 7 is a plan view showing the vicinity of a blade according to a third embodiment of the present invention.
{Fig. 8} Fig. 8 is a plan view showing a blade and a blade groove according to a fourth embodiment of the present invention.

{Description of Embodiments}

Embodiments of the present invention will be described below with reference to Figs. 1 to 8.
Fig. 1 is a longitudinal sectional view showing an example rotary compressor to which the present invention can be applied. Fig. 2 is a transverse sectional view showing a compression mechanism portion of the rotary compressor, along the line II-II of Fig. 1.
As shown in Fig. 1, a rotary compressor 1 includes a cylindrical hermetic housing 2, an electric motor 3 that is installed at a center portion in the hermetic housing 2, and a compression mechanism portion 4 that is provided below the electric motor 3 and is driven by the electric motor 3 to compress refrigerant gas.
The hermetic housing 2 is a cylindrical hollow housing in which a top cover 2c and a bottom cover 2b are welded at upper and lower ends of a cylindrical part 2a. One end of a suction pipe 5 connected to the compression mechanism portion 4 is connected to a lower portion of the cylindrical part 2a so as to penetrate therethrough, and installation legs 6 of the compressor are provided at places on an outer circumferential portion of the cylindrical part 2a. The suction pipe 5 is connected to an accumulator 7 that is supported on the outer circumference of the hermetic housing 2, and the accumulator 7 is connected to a refrigeration cycle. Furthermore, a discharge pipe 8 that is connected to the refrigeration cycle (not shown) is connected to the top cover 2c so as to penetrate therethrough.
The electric motor 3 is composed of a stator 3a and a rotor 3b. The stator 3a is fixed to an inner circumferential surface of the cylindrical part 2a of the hermetic housing 2, and the rotor 3b is rotatably fitted into an inner circumference of the stator 3a so as to have a predetermined clearance, with the rotor 3b being fixed to a rotating shaft (crankshaft) 9. A lower end portion of the rotating shaft 9 extends toward the compression mechanism portion 4, which is located below, and is rotatably supported via an upper bearing 12 and a lower bearing 13, to be described later, that constitute the compression mechanism portion 4. Furthermore, the rotating shaft 9 is provided with an eccentric part 9a at a lower portion thereof and an oil supply hole 9b therein along the axial direction.
The compression mechanism portion 4 is composed of a cylinder main body 11, the upper bearing 12, the lower bearing 13, a rotor 14, and a blade 17.
The cylinder main body 11 has a columnar cylinder chamber 10 on the inner circumferential side and is fixed to the inner circumferential surface of the hermetic housing 2 at multiple points on the circumference of housing 2 through welding.
The upper bearing 12 and the lower bearing 13 are screwed to upper and lower surfaces of the cylinder main body 11, respectively, thus sealing upper and lower surfaces of the cylinder chamber 10 and also rotatably supporting the rotating shaft 9.
The rotor 14 is a cylindrical part, and is hermetically and rotatably fitted onto the outer circumference of the eccentric part 9a of the rotating shaft 9, and orbits in the cylinder chamber 10 in accordance with eccentric rotation of the eccentric part 9a, and an outer circumferential surface 14a (see Fig. 2) thereof is brought into sliding contact with or rolls on an inner circumferential surface 10a of the cylinder chamber 10.
The blade 17 is a plate-like part, which is also generally called a vane, and is slidably provided in one blade groove 15 that is formed in the cylinder main body 11 and that extends in the radial direction. A rear end portion 17b of the blade 17 is pressed by a blade spring 16 that is provided in the blade groove 15 in a manner allowing elastic deformation, so that the blade 17 is always biased in the direction in which the blade 17 protrudes toward the cylinder chamber 10.
Because a front end portion 17a of the blade 17 abuts on the outer circumferential surface 14a of the rotor 14 (contact resulting from biasing by the spring), the space in the cylinder chamber 10 is partitioned by the blade 17 into a suction side 18 and a compression side 19. The blade 17 reciprocates in the blade groove 15 in accordance with orbiting of the rotor 14, thus being extended from and retracted into the groove.
A suction port 20 opens at the suction side 18 of the cylinder chamber 10, and low-pressure refrigerant gas is suctioned to the suction side 18 via the suction pipe 5 connected to the suction port 20. Furthermore, a discharge port 21 opens at the compression side 19 of the cylinder chamber 10, and compressed gas is discharged, via the discharge port 21 and a discharge valve 22 for opening and closing the discharge port 21, to a discharge chamber 24 that is formed by a discharge cover 23 provided on the upper bearing 12.
An oil pump 25 that pumps lubricant oil filled in a bottom portion of the hermetic housing 2 into the oil supply hole 9b, which is located inside the shaft, is provided near the lower end portion of the rotating shaft 9, so that the lubricant oil can be supplied to a lubrication point of the compression mechanism portion 4 via the oil pump 25 and the oil supply hole 9b. The above-described configuration of the rotary compressor 1 is not special, and is known.
As shown in Fig. 2, as is well-known, in the compression operation of the rotary compressor 1, during a first orbiting of the rotor 14 in which it orbits in the direction of the arrow from a top dead center across the suction port 20, due to rotation of the rotating shaft 9 (the eccentric part 9a), while the volume of the suction side 18 is being gradually enlarged, low-pressure refrigerant gas is suctioned into the suction side 18 via the suction port 20. This low-pressure gas is compressed while the volume of the suction side 18 is being gradually reduced after the suction process is stopped due to the rotation of the rotor, pushes and opens the discharge valve 22 from the compression side 19 when the gas is compressed to a predetermined pressure, and is discharged to the discharge chamber 24 via the discharge port 21.
The blade 17 is pushed by the blade spring 16 during the aforementioed operation, with the front end portion 17a thereof being brought into contact with the outer circumferential surface of the rotor 14, the blade 17 slides to be extended from and retracted into the blade groove 15, in accordance with orbiting of the rotor 14. Fig. 3 schematically shows the behavior of the blade 17 when it protrudes into the cylinder chamber 10 during the compression operation. The blade 17 is extended and retracted (reciprocates) with the front end portion 17a thereof protruding toward the cylinder chamber 10, except for the position at the top dead center. Thus, the blade 17 is subjected to a pressure difference in the direction of the arrow toward the suction side 18 due to the pressure difference Δp between the pressure at the suction side 18 and the pressure at the compression side 19.
For this reason, the blade 17 slides while being tilted relative to the blade groove 15 by an amount in accordance with a slide gap, so that the blade 17 slides while being brought into partial contact with the blade groove 15 at a position 17c that is in contact with a front end of a side surface of the blade groove 15 on the suction side 18 and at a position 17d that is in contact with the vicinity of a rear end of a side surface of the blade groove 15 on the compression side 19.
Specifically, the blade 17 is subjected to force concentrated on a line due to the partial contact, and the positions on the blade 17 that are subjected to the load change due to the reciprocation of the blade 17. Because of this partial contact, there is a risk that an oil film of lubricant oil mixed in refrigerant gas may breakdown, thus causing wear to progress and causing compressor seizure. Thus, in the present invention, a hollow portion is provided in the blade 17, as described below.

[First Embodiment]

Fig. 4 is a plan view showing the vicinity of a blade 17 according to a first embodiment of the present invention.
The blade 17 has a hollow portion 171 therein. The hollow portion 171 is open on three sides, i.e., the rear end portion 17b of the blade 17 and both side portions thereof, namely, an upper side and a lower side of the blade 17. Furthermore, the hollow portion 171 is formed from the rear end to the vicinity of the front end portion 17a of the blade 17. More specifically, respective portions of the blade 17 that surround the hollow portion 171 have a fixed thickness.
Here, the width of the hollow portion 171 or the thicknesses of the respective portions of the blade 17 are set to such a thickness that the blade 17 can be slightly bent in a thickness direction thereof when the above-described pressure difference Δp between the pressure at the suction side 18 and the pressure at the compression side 19 is applied on the blade 17 during the compression operation of the rotary compressor 1, as shown in Fig. 5.
The hollow portion 171 can be formed simultaneously when the blade 17 is formed by bending a sheet-metal material into a channel section shape in a plan view. Alternatively, after the blade 17 is cut out from a solid metal material or is punched by press work, the hollow portion 171 may be formed by machining.
During the compression operation of the rotary compressor 1, the blade 17, which has the hollow portion 171 provided therein, is subjected to a contact pressure due to the pressure difference Δp between the suction side 18 and the compression side 19 and slides while being tilted toward the suction side 18 by an amount in accordance with a slide gap between the blade 17 and the blade groove 15, as shown in Fig. 5. At the same time, the blade 17 is slightly bent toward the suction side 18.
When the blade 17 is bent toward the suction side 18 in this way, the contact areas at the positions 17c and 17d where the side surfaces of the blade 17 are brought into partial contact with the blade groove 15 are increased, thus bringing the positions 17c and 17d into surface contact with the blade groove 15 and reducing a PV value. Therefore, the oil film is less likely to breakdown at contact portions between the blade 17 and the blade groove 15, thus preventing wear from progressing and compressor seizure from occurring at the contact portions and enhancing the reliability of the rotary compressor 1.
Furthermore, when compressed refrigerant gas flows from the gap of the sliding portion between the blade 17 and the blade groove 15 into the hollow portion 171 in the blade 17, the pressure of the compressed refrigerant brings both of the surfaces of the blade 17 into contact with the inner surfaces of the blade groove 15 through elastic deformation. Accordingly, the slide gap becomes small, thus improving the sealability, and leakage of the compressed refrigerant from a high-pressure side (the compression side 19) to a low-pressure side (the suction side 18) (gas leakage loss) can be reduced, thus enhancing the compression efficiency of the rotary compressor 1.
Furthermore, because the hollow portion 171 is formed from the rear end to the vicinity of the front end portion 17a of the blade 17, the thickness of the blade front end portion 17a is reduced, and the blade front end portion 17a is softened and brought into contact with the outer circumferential surface 14a of the rotor 14 in a wide area. Accordingly, it is possible to reduce the contact surface pressure at the blade front end portion 17a, which prevents breakdown of the oil film, wear, and compressor seizure, thus enhancing the reliability of the rotary compressor 1.

[Second Embodiment]

Fig. 6 is a plan view showing the vicinity of a blade 17 according to a second embodiment of the present invention.
In the blade 17 shown here, a hollow portion 172 formed therein is shorter than the hollow portion 171 of the first embodiment.
Specifically, when the blade 17 is fully extended, as shown in Fig. 6, the hollow portion 172 only needs to be formed from the rear end to at least a position that is located at the front end side relative to a rear end position 17e at which the blade 17 protrudes from the blade groove 15 into the cylinder chamber 10. In this embodiment, the hollow portion 172 is formed to have a length L from the rear end position 17e.
By forming the hollow portion 172 from the rear end to the above-described position, it is possible to reduce the machining cost, compared with the case in which the hollow portion 171 is formed from the rear end to the vicinity of the front end portion 17a of the blade 17, as shown in Fig. 4. The advantageous effect produced when the blade 17 is bent due to the hollow portion 172 is the same as or similar to that in the first embodiment.
Furthermore, in this way, a portion of the blade 17 closer to the rear end portion 17b is hollowed, a portion of the blade 17 closer to the front end portion 17a is made solid, and the length of the hollow portion 172 (the length L) is adjusted, thereby making it possible to appropriately adjust the amount of bending of the blade 17 in accordance with the characteristics of the rotary compressor 1.

[Third Embodiment]

Fig. 7 is a plan view showing the vicinity of a blade 17 according to a third embodiment of the present invention.
In this embodiment, a hollow portion 173 formed in the blade 17 has a through-hole 173a that penetrates the blade 17 in the vicinity of the front end portion 17a along the axial direction of the rotating shaft 9 (the eccentric part 9a) and a slit 173b that is formed so as to extend from the rear end portion 17b of the blade 17 to the through-hole 173a.
The through-hole 173a is formed by drilling using a drill, for example, and the slit 173b is formed by cutting through wire cutting, for example. Here, an inner width W of the slit 173b is less than an inner diameter d of the through-hole 173a.
With the above-described configuration, it is possible to make the thickness in the vicinity of the front end portion 17a of the blade 17 thinner than the thicknesses of intermediate and other portions of the blade 17 and to soften the blade front end portion 17a to bring it into contact with the outer circumferential surface 14a of the rotor 14 in a wide area, thus reducing surface pressure, which prevents breakdown of the oil film, wear, and compressor seizure of the blade 17, and enhancing the reliability of the rotary compressor 1.

[Fourth Embodiment]

Fig. 8 is a plan view showing a blade 17 and a blade groove 15 according to a fourth embodiment of the present invention.
In this embodiment, although a hollow portion 171 formed in the blade 17 has the same shape as the hollow portion 171 formed in the blade 17 of the first embodiment, the hollow portion 171 of this embodiment may have the shape of the hollow portion 172 of the second embodiment, the shape of the hollow portion 173 of the third embodiment, etc.
In this embodiment, a maximum width W1 of the blade 17 at the rear end portion 17b is set slightly larger than an inner width W2 of the blade groove 15 such that both surfaces of the blade 17 are brought into contact with the inner surfaces of the blade groove 15 in a lightly elastically deformed state. The difference in width is set so as not to disturb smooth movement of the blade 17 in the blade groove 15 when inserted and operated into the blade groove 15.
By doing so, the gap at the sliding portion between the blade 17 and the blade groove 15 becomes very small, thus making compressed refrigerant less likely to leak from the gap. Accordingly, it is possible to reduce leakage of compressed refrigerant from the high-pressure side (the compression side 19) to the low-pressure side (the suction side 18), that is, gas leakage loss, thus enhancing the compression efficiency of the rotary compressor 1. Furthermore, unnecessary vibrations etc. of the blade 17 in the blade groove 15 can be effectively suppressed.
Therefore, according to the first to fourth embodiments, it is possible to reduce the PV value (the product of the contact pressure P and the blade sliding speed V) acting on the side surfaces and the front end portion 17a of the blade 17 during the compression operation of the rotary compressor 1, to prevent wear, compressor seizure, etc. of the blade 17 to enhance the reliability, and to reduce leakage of compressed refrigerant from a gap of the sliding portion between the blade 17 and the blade groove 15, thus achieving enhanced compression efficiency.
Note that the present invention is not limited to the above-described embodiments, and modifications can be appropriately made without departing from the scope thereof. For example, in the above-described embodiments, although a description has been given as an example case in which the present invention is applied to the single-cylinder rotary compressor 1, which is provided with one cylinder chamber 10, the present invention is not limited thereto and can be applied to a multicylinder rotary compressor that is provided with a plurality of cylinder chambers 10 or a multistage rotary compressor, as a matter of course. Furthermore, although an example case in which the present invention is applied to the hermetic-type rotary compressor 1 has been described, it is needless to say that the present invention can be applied to open-type compressors.

{Reference Signs List}

1: rotary compressor
3: electric motor
4: compression mechanism portion
9: rotating shaft
9a: eccentric part
10: cylinder chamber
10a: inner circumferential surface of cylinder chamber
11: cylinder main body
14: rotor
14a: outer circumferential surface of rotor
15: blade groove
17: blade
17a: front end portion of blade
17b: rear end portion of blade
17e: position at which blade protrudes from blade groove when
fully: extended
18: suction side
19: compression side
171, 172, 173: hollow portions
173a: through-hole
173b: slit

Claims

A rotary compressor (1) characterized in that it comprises:
a cylinder main body (11) that forms a cylinder chamber (10) ;

a rotor (14) that is fitted onto an eccentric part (9a) of a rotating shaft (9), that orbits in the cylinder chamber (10) in accordance with rotation of the rotating shaft (9), and whose outer circumferential surface (14a) is brought into sliding contact with an inner circumferential surface (10a) of the cylinder chamber (10); and

a blade (17) in which a front end portion (17a) is brought into contact with the outer circumferential surface of the rotor (14) to partition the inside of the cylinder chamber (10) into a suction side (18) and a compression side (19), the blade being configured to slide in a groove (15) provided in the cylinder main body (11) so as to be extended from and retracted into the groove (15) in accordance with orbiting of the rotor (14),

wherein the blade (17) has a hollow portion (171; 172; 173) therein that allows the blade (17) to be bent in a thickness direction thereof; and

the hollow portion (171; 172; 173) is open to the outside of the blade at a rear end portion and both side portions of the blade.
The rotary compressor (1) according to claim 1, wherein the hollow portion (171; 173) is formed from the rear end (17b) to a vicinity of a front end portion (17a) of the blade (17).
The rotary compressor (1) according to claim 1, wherein the hollow portion (172) is formed from the rear end (17b) and at least to a position which is located at a front end side relative to a rear end position (17c) of the blade (17) at which the blade protrudes from the blade groove (15) into the cylinder chamber (10) when the blade is fully extended.
The rotary compressor according to claim 1 or 2, wherein the hollow portion (173) is provided with a through-hole (173a) that penetrates the blade in a vicinity of a front end portion (17a) along the axial direction of the rotating shaft, and a slit (173b) that is formed so as to extend from the rear end portion (17b) of the blade to the through-hole (173a) and that has an inner width (W) narrower than an inner diameter (d) of the through-hole (173a).
The rotary compressor according to one of claims 1 to 4, wherein a maximum width (W1) of the blade at the rear end portion (17b) is set larger than an inner width (W2) of the blade groove (15) such that both surfaces of the blade are brought into contact with inner surfaces of the blade groove (15) in a lightly elastically deformed state.