US3565552A - Rotary compressor - Google Patents

Abstract

A ROTARY COMPRESSOR WHEREIN A MOTOR AND A FRAME CARRYING THE ROTARY AXLE OF SAID MOTOR ON BEARINGS ARE ENGAGEABLY FITTED IN A SEALED CASE HAVING A LUBRICANT RESERVOIR INTEGRALLY FORMED AT THE BOTTOM, THE BOTTOM PART OF THE FRAME IS FITTED WITH A CYLINDER WHICH COMPRISES A COMPRESSION CHAMBER HAVING A ROTOR FITTED TO THE ROTARY AXLE OF THE MOTOR IN SUCH A MANNER THAT THE SURFACE OF SAID ROTOR ROTABLY SLIDES ON THE INNER SURFACE OF THE COMPRESSION CHAMBER, A BLADE SLIDING SLOT ALLOWING A BLADE TO BE FITTED SLIDABLY THERETHROUGH, AND A LUBRICANT FEEDER COMMUNICATING WITH SAID BLADE SLIDING SLOT AND OPEN TO THE LUBRICANT RESERVOIR IN A STATE IMMERSED IN THE LUBRICANT CONTAINED THEREIN, WHEREBY A LUBRICANT FOR THE BLADE IS FED TO THE BLADE SLIDING SLOT DIRECTLY FROM THE LUBRICANT RESERVOIR THROUGH THE LUBRICANT FEEDER.

Description

Feb. 23, 1971 TUNE@ MONDEM ETAL 3,565,552

ROTARY COMPRESSOR Filed March 18, 1969 Patented Feb. 23, 1971 had 3,565,552 ROTARY COMPRESSOR Tuneo Mondem, Tokyo, Masao Ozu, Yokohama-shi, Ma-

koto Watanabe, and Keiji Noda, Kawasaki-shi, Japan, assignors to Tokyo Shibaura Electric C0., Ltd., Kasasaki-shi, Japan, a corporation of Japan Filed Mar. 18, 1969, Ser. No. 808,253 Claims priority, application Japan, Mar. 19, 1968, 43/ 18,433; May 30, 1968, i3/44,474 Int. Cl. F04c 29/02 U.S. Cl. 417-372 7 Claims ABSTRACT OF THE DISCLOSURE A rotary compressor wherein a motorand a frame carrying the rotary axle of said motor on bearings are engageably fitted in a sealed case having a lubricant reservoir integrally formed at the bottom, the bottom part of the frame is fitted with a cylinder which comprises a cornpression chamber having a rotor fitted to the rotary axle of the motor in such a manner that the surface of said rotor rotatably slides on the inner surface of the compression chamber, a blade sliding slot allowing a blade to be fitted slidably therethrough, and a lubricant feeder communicating with said blade sliding slot and open to the lubricant reservoir in a state immersed in the lubricant contained therein, whereby a lubricant for the blade is fed to the blade sliding slot directly from the lubricant reservoir through the lubricant feeder.

BACKGROUND OF THE INVENTION The present invention relates to a rotary compression and more particularly to improvements in a device for lubricating blades.

With a conventional rotary compressor the blade was lubricated in the following manner. A lubricant contained in a lubricant reservoir positioned at the bottom of the casing was sucked up as a result of the rotation of the rotary axle by means of said rotary axle into the case in which there was housed a motor. Part of the sucked lubricant was allowed to flow into the spiral blade sliding slot communicating with the compression chamber to lubricate the blade. On the other hand, the pressure prevailing in the compression chamber positioned in the cylinder, namely, in both high and low pressure regions thereof, was generally lower than that present in the case. This pressure difference caused the lubricant flowing to the blade sliding slot to be introduced into a clearance between the blade and its sliding slot and then into the compression chamber while lubricating said clearance. With this method, however, the lubricant took a time of about to 10 seconds in reaching the blade sliding slot after the start of the rotary compressor. Accordingly, there were encountered problems with the lubrication of the blade immediately after the start. Further, the lubricant introduced into the blades sliding slot traveled through the case while lubricating the motor mechanism, so that it was contaminated with foreign matter such as line particles generated by friction, thus failing to perform satisfactory lubrication.

SUMMARY OF THE INVENTION The present invention has been accomplished in view of the aforementioned drawbacks of the prior art, and relates to the lubrication of a rotary compressor, and particularly to a device for lubricating the blade. The invention is intended to make improvements in the lubrication of the blade, particularly said lubrication immediately after the start of the compressor, by providing a different circuit for lubricant from what was used in the prior art. More concretely, the invention is characterized in devising a new type of circuit using a lubricant feeder.

According to the rotary compressor of the present invention, there is housed a cylinder in a sealed case. In the cylinder is formed a compression chamber in which there is fitted an eccentric rotor rotatably sliding on the inner surface of said compression chamber. In the cylinder is also formed in communication with the compression chamber a blade sliding slot which allows the blade to be engaged therewith in a manner to slide back and forth with the furthest end always contacting the circumferential surface of the rotor.

The present rotary compressor further comprises a lubricant feeder disposed at the bottom of the cylinder so as to allow the blade sliding slot to communicate directly or indirectly with the lubricant reservoir integrally formed at the bottom of the case. Thus the difference between the pressure in the high pressure case communicating with the lubricant reservoir and the pressure in the low pressure compression chamber which is lower than the former causes the lubricant of the reservoir to be sucked up into the compression chamber through the clearance between the blade and blade sliding slot. The lubricant together with an amount of lubricant charged from the lubricant reservoir through the rotary axle further passes through a spiral slot formed in the surface of the rotary axle with which the rotor eccentrically registers so as to lubricate said axle and then travels to the case to lubricate the motor housed therein, and finally flows back to the reservoir. In this case it is also possible to allow part of the lubricant conducted to the case to pass through a hole communicating with the case and blade sliding slot so as to be brought into the blade sliding slot thereby to lubricate the blade for a second time.

According to this invention, the lubricant is sucked from the reservoir through the lower end of the rotary axle to lubricate the rotary axle and the motor mechanism, similarly as in a conventional rotary compressor.

The lubricant for lubricating the blade according to this invention is fed to the blade sliding slot directly from the lubricant reservoir through the lubricant feeder. This not only allows the blade to be lubricated substantially at the same time the rotary compressor starts, but also the lubricant to be supplied at a low temperature with the resultant greater strength of the film of said lubricant.

Further, the lubricant used in lubricating the blade is supplied only from the lubricant reservoir through the lubricant feeder communicating with the blade sliding slot, thus preventing the lubricant flowing through the case housing a motor from being directly supplied to lubricate the blade as has been the case with the conventional rotary compressor. This also keeps the blade sliding slot free from the intrusion of foreign matter such as fine particles caused by friction and avoids the wear of the blade and its sliding slot which will have a harmful effect on the sliding and lubrication of the blade.

BRIEF EXPLANATION OF THE DRAWINGS The appended drawings schematically represent the arrangements embodying the present invention.

FIG. 1 is a longitudinal sectional view of an embodiment of the invention;

FIG. 2 is a transverse plan view on line II-II of FIG. 1;

FIG. 3 is an enlarged view of a blade section of FIG. 2; and,

FIGS. 4 and 5 represent the longitudinal sectional view of other embodiments of the invention, omitting the motor mechanism.

3 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the invention is shown in FIGS. 1 'to 3 in which like or similar parts are designated by the same reference numerals. In FIG. 1, a casing 1 comprises two sections 1a and 1b of hermetically sealed construction. Within the casing 1 is forcedly tted the stator 2 of a motor to support the rotary axle of the rotor 3 of the motor. Into the casing or case 1 and below the stator 2 1s engageably fitted a frame 7 which carries the rotary axle 4 of a motor rotor 3 on bearings and holds a cylinder body 6. In the center of the frame 7 is integrally formed an upwardly projecting cylindrical bearing section 8 for receiving the rotary axle 4, and the part of the frame 7 which does not overlap the cylinder body 6 below is perforated with a port 9 for the return flow of a lubricant. On the peripheral edge of the frame 7 is formed an annular protruding edge 10 which serves as a guide when the frame 7 is inserted into the case 7 and also as a recess for receiving a coil 5 of stator 2. And the case 1 has a lubricant reservoir 11 integrally formed at the bottom.

The cylinder 6 is fitted to the underside of the frame 7 by a suitable means such as a bolt. A compression chamber 12 formed in the cylinder 6 has an eccentric rotor section 13 disposed at the bottom end of the rotary axle 4, and the outer circumference of said eccentric rotor section 13 is fitted with a rotor 14. When the motor rotates, the eccentrically expanding part of the rotor 14 is so arranged to rotate slidably on the inner surface of the compression chamber. In order to suck the lubricant from the lubricant reservoir, a hole 15 is formed in the lower end of the rotary axle along its axial direction, and the rotary axle 2 has a spiral slot 16 formed in its circumferential surface and communicating with said hole 15. The cylinder 6 also has a blade sliding slot 17 formed in communication with the compression chamber 12 in the normal direction thereof, and a blade 18 is slidably fitted into said slot 12. At the rear end of the blade sliding slot 17 is disposed a spring chamber 10 in a communicable relationship therewith. In the spring chamber 19 is housed a coil spring 20 which presses the blade 18 toward the rotor 14 and allows the blade 18 to slide back and forthas a result of its eccentric rotation with its furthest end always contacting the circumferential surface of the rotor 14. The compression chamber 12 is separated into a high pressure region 12a and low pressure region 12b by means of the blade 18 and the eccentrically expanding part of the rotor 14. In those portions of both side walls of the blade sliding slot 17 which are located near the spring chamber 19, there are formed lubricant ducts 28 and 29. The bottom plate 26 of the blade sliding slot 17 contacting the cylinder in an airtight relationship as described later is perforated with a hole 30 communicating wtih the lubricant ducts 28 and 29. The upper open end portion of a lubricant feeder 31 is inserted into the hole 30 and the lower end portion of said lubricant feeder 31 is immersed in the lubricant at a point close to the bottom part of the lubricant reservoir 11. The cylinder `6 has a low pressure gas sucking port 21 communicating with the low pressure region 12b of the compression chamber 12 and a high pressure gas discharge port 22 communicating with the high pressure region 12a. This discharge port 22 communicates through a discharge valve 23 having a valve stopper 23a with a discharge chamber 24 provided in the cylinder separately from the compression chamber 12. The

`discharge chamber 24 communicates with the case 1 through a bore 25 perforated in the frame 7. The upper opening of each of the compression chamber 12, blade sliding slot 17, spring chamber 19 and discharge chamber 24 involved in the cylinder 6 is sealed with the frame 7 and the lower opening thereof is hermetrically closed with a bottom plate 26 attached thereto. To the bottom plate 26 is fitted the bottom end of the rotary axle 4 which is carried on bearings, and a hole 27 is formed in the bottom plate 26 so that it intercommunicates the port 15 formed in the rotary axle, with the reservoir. The reservoir 11 communicates through the lubricant return port 9 with the case in which there prevails a high pressure. To the sucking port 21 formed in the compression chamber 12 of the cylinder 6 is connected a sucking pipe (not shown) extending outside of the case 1 and the upper side of the case 1 is provided with a discharge port (not shown).

There will now be described the operation of an embodiment of the present invention. The rotation of the motor rotor 2 causes the rotary axle 4 to rotate and the resultant rotation of the rotor 14 enables a cycle of suction, compression and discharge to be continuously repeated in the compression chamber 12. :In this case, the pressure 1n the sealed case is raised by the gas discharge from the high pressure region 12a of the compression chamber, with the result that the pressure in both high and low pressure regions 12a and 12b of the compression chamber 12 falls below that present in the case 1. This pressure difference allows the lubricant of the reservoir 11 to be sucked up from the lubricant feeder 31 to flow into the lubricant ducts 28 and 29 and then into compression chamber 12 while lubricating the clearance between the blade 18 and its sliding slot 17. At the same time, as the rotary axle 4 rotates, the lubricant is sucked from the lubricant reservoir through the hole 27 formed in the rotary axles and fed to the compression chamber 12 and to the spiral slot 15 formed in the rotary axle. The amounts of lubricant is further conducted into the case while lubricating the rotary axle 4 by flowing through the spiral slot 16 formed therein. Part of the lubricant is supplied to lubricate the motor mechanism and the remainder runs back to the reservoir 11 through the return port 9 of the frame 7. Thus is successively carried out the lubrication of the blade and rotary axle.

There will now be described another embodiment of the present invention by reference to FIG. 4. This embodiment has the same arrangement as the one jointly shown in FIGS. 1 to 3 (the same parts of FIG. 4 as those of FIG. 1 are denoted by the same numerals), excepting that the blade section has the undermentioned construction.

Unlike the rotary compressor of the first embodiment, the second .embodiment of FIG. 4 causes the lubricant ducts 28 and 29 formed at some position of both sides of the blade sliding slot 17 and the port 30 perforated at the bottom part of the blade sliding slot 17 in communication with said ducts 28 and 29 to be fully closed, and the open bottom end of the lubricant feeder 31 to be immersed in the lubricant at a point close to the bottom of the lubricant reservoir 11, and the upper end of said feeder 31 to be inserted through a port perforated at the bottom of the spring chamber 19 in such a manner that said upper .end slightly projects upward from the bottom of said chamber.

There will now be described the operation of the enibodiment of FIG. 4. As in the first embodiment, the pressure difference in the high pressure case 1 and the spring chamber 19 communicating with the compression chamber 12 having a lower pressure than that present in said case 1 causes the lubricant of the reservoir 11 to be sucked into the spring chamber 19 through the lubricant feeder 31, pass through the clearance between the blade 18 and its sliding slot 17 and flow into the compression chamber 12 while lubricating all the surface of the blade. The lubricant introduced into the compression chamber 12 later runs through the same circuit as in the first ernbodimeut back to the reservoir 11. The spring chamber 19 is of airtight construction except for those parts thereof which communicate with the top end of the lubricant feeder 31 and blade sliding slot 17, so that the reciprocal motion of the blade 17 causes the air volume in said spring chamber 19 to be varied. Thus when the blade slides backward into the spring chamber 19, part of the air contained'in said chamber 19 is forced out backward into the lubricant reservoir 11 through the lubricant feeder 31. However, when the blade slides forward into the compression chamber 12, the aforesaid pressure difference between the case 1 and compression chamber 12, coupled with the reduced pressure due to the volumeric expansion of air in the spring chamber 19, causes large amounts of lubricant to be sucked up into the spring chamber 19 through the lubricant feeder 31. The lubricant sucked up into the spring chamber 19 is allowed always to remain therein in volumes having a depth equal to the height of that portion of the lubricant feeder 31 which projects into the spring chamber 19.

With respect to the rst embodiment, it is possible to perforate the frame 7 with a port 32 which communicates with the case 1 housing the motor and the lubricant ducts 28 and 29 formed on both sides of the blade sliding slot 17, and cause part of the lubricant introduced into the case 1 from the rotary axle 4 to run through said port 32 into the blade sliding slot 17 so as to lubricate the blade for a second time. This arrangement is effective particularly for a large capacity and low pressure rotary compressor wherein the pressure of the case 1 acting on the lubricated surface of the blade is relatively low. In said first embodiment, the lubricant feeder 31 may also be tted with a lter 33 so as to filtrate the lubricant sucked up from the reservoir 11. FIG. presents an embodiment comprising such port 32 and lter 33, with the same parts as those of the preceding embodiments denoted by the same numerals.

According to the present invention, a sealed case having a lubricant reservoir integrally formed at the bottom in communication therewith contains a motor and a cylinder. In said cylinder there are formed a compression chamber, blade sliding slot and spring chamber in mutual communication relationship. On both side walls of the blade sliding slot are disposed lubricant ducts, and one of the open ends of a lubricant feeder communicating with said ducts is immersed in the lubricant. Thus the air cornpressed in the compression chamber is discharged from said chamber into the lubricant through a discharge valve to cause the pressure in the case to be higher than that in the compression chamber. This pressure difference allows the lubricant of the reservoir to be sucked up through the lubricant feeder and supplied for lubrication of the blade and rotary axle. The sucking up of lubricant through the feeder is carried out particularly at the moment the rotary compressor is started, thereby enabling the blade to be lubricated substantially at the same time.

Further, the lubricant for lubricating the blade is supplied only from the reservoir through the feeder, preventing the lubricant introduced into the motor mechanism for its lubrication from being supplied directly to the blade as has been the case with the prior art rotary compressor. Accordingly the lubricant is substantially free from the intrusion of foreign matter such as fine particles caused by friction. This prevents the wear of the blade and its sliding slot which will adversely affect the lubrication of the blade. Further, the present invention enables the lubricant to be supplied to the blade at temperatures more than about 20 C. lower than would be required with the conventional rotary compressor which was so designed as to lubricate the blade with the lubricant which flowed through the motor mechanism. Accordingly, the present invention assumes the greater strength of the lubricant film as well as the reduced temperature of the compression chamber. 'I'he supply of lubricant can also be controlled using a feeder having a proper inner diameter to meet such control. Further, in an aspect of the present invention, the lubricant feeder is disposed at the bottom of the spring chamber so as to cause the blade lubricant to flow from the spring chamber to the compression chamber through the clearance between the blade and its sliding slot, so that both side walls, as well as the top and bottom walls, of the blade sliding slot over its entire length is uniformly lubricated, enabling the blade also to be satisfactorily lubricated and its wear and damage to be effectively prevented. Since the spring chamber always contains a certain amount of lubricant, its supply can be started at the moment the rotary compressor is put into operation, so that the lubrication of the blade in the initial compressor operation can be commenced more quickly than has previously been possible.

What is claimed is:

1. A rotary compressor comprising:

a sealed case (1) having a lubricant reservoir (11) integrally formed at the bottom and a motor housed at the upper part thereof, the motor including a stator (2), a rotary axle (4) having a spiral slot (16) formed on the outer circumferential surface thereof starting at the bottom end thereof, and a rst rotorV (3) coupled to said axle (4);

a cylinder (6) containing a compression chamber (12), spring chamber (19) and a blade sliding slot (17) communicating with both of said chambers (12,v 19), both side walls of the blade sliding slot (17 having lubricant ducts (28, 29) extending from the bottom to the top on the surface of said side walls;

a second rotor (14) eccentrically coupled to the rotary axle (4) of the motor and disposed in the compression chamber (12) so as to rotate slidably on the inner surface of said compression chamber (12);

frame (7 formed below the motor in the case (1) having the cylinder (6) on the bottom thereof, the

frame (7) carrying the rotar yaxle (4) and the frame (7 having a return port (9) for the lubricant formed therein;

cylinder bottom plate (26) coupled to the bottom portion of the cylinder (6) so as to integrally constitute the bottom of the compression chamber (12),

blade sliding slot (17) and spring chamber (19),

respectively, said bottom plate (26) supporting the rotary axle (4) of the motor;

blade (18) slidably litted into the blade sliding slot (17); means (20) in the spring chamber (19) for biasing one end of the blade (18) toward the second rotor (14) so that said one end bears on the second rotor (14); and

a lubricant feeder (31) communicating said cylinder 6) with said lubricant reservoir (11).

2. The rotary compressor according to claim 1 wherein the return port (9) is formed in the frame (7) at a point which does not overlap the cylinder 6) 3. The rotary compressor according to claim 1 wherein the frame (7 further includes a port (32) formed therein for communicating the lubricant ducts (28, 29) with the case (1) housing the motor.

4. The rotary compressor according to claim 1 wherein the biasing means (20) includes a spring (20) mounted in the spring chamber (19).

5. The rotary compressor according to claim 1 wherein the lubricant feeder (31) has an upper open end which is coupled to the bottom of the blade sliding slot (17) and a lower open end which is immersed in the lubricant of the lubricant reservoir (11).

6. The rotary compressor according to claim 1 wherein the lubricant feeder (31) has an upper open end which is coupled to the bottom of the spring chamber (19) and a lower open end which is immersed in the lubricant reservoir.

7. The rotary compressor according to claim 1 wherein the lubricant feeder (31) includes a lter (33) provided therein.

References Cited UNITED STATES PATENTS Y2,669,384 2/1954 Dills 230-139X 2,883,101 4/ 1959 Kosfeld 230-207 2,988,267 6/1961 Kosfeld 230-207 3,003,684 10/1961 Tarleton 230-207 ROBERT M. WALKER, Primary Examiner

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