US3334808A

US3334808A - Compressor lubrication arrangement

Info

Publication number: US3334808A
Application number: US504327A
Authority: US
Inventors: Sidney A Parker; Richard E Cawley
Original assignee: Lennox Industries Inc
Current assignee: Lennox Industries Inc
Priority date: 1965-10-24
Filing date: 1965-10-24
Publication date: 1967-08-08
Anticipated expiration: 1984-08-08
Also published as: BE686039A; DE1503446A1; GB1157523A; NL6608312A; DK124835B

Description

g 1957 s. A. PARKER ETAL 3,334,808

COMPRESSOR LUBRICATION ARRANGEMENT Filed Oct. 24, 1965 INVENTORS SIDNEY A. PARKER i5 1. RICHAQD E. CAWLEY United States Patent 3,334,808 COMPRESSOR LUBRICATION ARRANGEMENT Sidney A. Parker and Richard E. Cawley, both of Fort Worth, Tex., assignors to Lennox Industries Inc., a corporation of Iowa Filed Oct. 24, 1965, Ser. No. 504,327 12 Claims. (Cl. 230-206) ABSTRACT OF THE DISCLOSURE This invention relates to a hermetic refrigerant compressor and, more particularly, to an improved compressor of the type having a vertical crankshaft and including means on the crankshaft for reducing the oil level in the crankcase during operation below the operating mechanism to reduce the energy losses and thereby reduce the watts input to the compressor motor.

The trend in the refrigeration industry is toward compact refrigerant compressors driven at relatively high speeds. In one type compressor design, the vertically extending crankshaft is journaledin a crankcase resiliently supported in a sealed outer casing, with the drive motor for the crankshaft being located above the compression mechanism in the crankcase.

The hermetic compressor includes a welded shell or outer casing, the lower portion of which defines an oil sump.'When the compressor is inoperative, the crankcase is partially submerged in the sump and some oil is within the crankcase above the level of the operating mechanism therein. A relatively large supply of oil is desirable to reduce the adverse effects caused by miscibility of refrigerant and oil. However, it is desirable to remove oil from the crankcase in use or to reduce the oil level below the pistons and flywheel portion on the drive shaft to minimize operational losses due to frictional drag of the drive shaft and parts of the compression mechanism in the oil and to decrease the watts input to the electric drive motor.

In operation of one present compressor design, disclosed for example in Gerteis Patent 3,008,629 discharge gas bypasses around the pistons, increasing the pressure within the crankcase, which is open to the crankcase only below the normal level of oil or lubricant in the sump. The difference in pressures acting on the oil displaces the oil from within the crankcase. By this construction, there is provided a compact hermetic compressor design, for lubricant is displaced into the annular space defined between an annular sleeve carrying the crankcase and the lower portion of the outer casing.

The above noted compressor design is dependent upon an imperfect mating of a piston and its sealing rings Within a cylinder in the compressor block. With modern fabricating equipment and techniques, there need not be very much leakage of gas between a piston and the wall of an associated cylinder. If there were only very little leakage, insufficient pressure would be built up in the crankcase to force the oil or like lubricant through an opening therein below the level of oil in the sump. Further, under low load conditions, there would be little bypass or blowby of discharge gas about the pistons of the compression mechanism and thus, there would be insufficient pressure in the crankcase to displace lubricant therefrom.

It is desired that oil be removed from within the crankcase during operation in order to minimize interference with the pumping.

Further, as compressors of this type are built in larger sizes and cylinder unloading means are utilized, there would be insuflicient bypass of discharge gases about the pistons during unloading conditions to pressurize the crankcase.

An object of the present invention is to provide a hermetic refrigerant compressor having fan means on the crankshaft Within the outer casing for pressurizing the crankcase independent of piston bypass for positively reducing the level of lubricant in the crankcase during operation.

Another object of the present invention is to provide va hermetic refrigerant compressor having compression mechanism within which is defined a crankcase at least partially filled with lubricant when the compression mechanism is inoperative, with pump means in the crankshaft and with fan means on the crankshaft for pressurizing the crankcase to displace the lubricant from the crankcase during operation into the sump in the outer casing so as to reduce the level of oil in the crankcase below the operating components therein, said fan means communicating with the pump means for receiving lubricant from the pump means and returning it to the crankcase in a path isolated from the suction case. Further objects and advantages of this invention will become more apparent hereafter.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which FIG. 1 is a cross-sectional view of a hermetic refrigerant compressor embodying the present invention;

FIG. 2 is a plan view of the fan on the crankshaft for pressurizing the crankcase in the compression mechanism; and

FIG. 3 is a perspective view of the fan and illustrating a portion of the annular sealing ring which cooperates with the lower fan housing portion of the fan to minimize recirculation of gas.

Referring to FIG. 1, there is illustrated a refrigerant compressor 10 embodying the present invention. The compressor comprises a gas-tight housing including an upper shell 12 and a lower shell 13 integrally joined to one another, as for example, by welding. A plurality of legs 14 may be welded to the lower shell of the compressor for supporting the compressor in an upright position.

Resiliently supported within the outer housing or casing of the compressor 10 is a compression mechanism that includes a compressor block 15 surrounded and partially enclosed by an annular sleeve 20. The compressor block 15 comprises a motor flange portion 16 and a cylinder crankcase flange portion 17 divided by a partition 18.

Surrounding the lower portion 17 of the crankcase in spaced relationship to the lower shell -13 .of the outer casing is the annular sleeve 20. Formed integrally on the top of the annular sleeve 20 is an out-turned, ring-like flange 21. An annular member 22 having a transversely disposed lower ring-like flange 23 is aflixed to the lower shell 13. A plurality of resilient spring means 24 are provided between the flange members 2.1 and 23 for resiliently supporting the crankcase within the outer housing.

Provided within the crankcase 15 are a plurality of cylinders 26. Though a four-cylinder compressor is illustrated, it will be understood by those versed in the art that any desired number of cylinders may be employed.

Cylinder sleeves or liners 27 are provided in each of the cylinders 26 and a suitable piston 28 is adapted to recipro-. cate within each of the cylinder liners 27. Each piston 28 is operatively connected to the eccentric portion 29 of the vertically disposed crankshaft 30, which is journaled in spaced bearings within the crankcase 15. The means for operatively connecting the piston 28 to the crankshaft 30 include a connecting rod 32, which is affixed at one end of the eccentric portion 29 of crankshaft or drive shaft 30 and at the other end to a wrist pin 34 carried in piston 28.

Closing the end of each cylinder cavity is a valve assembly 36. Such valve assembly may comprise a discharge valve unit 37, a suction valve plate 38 and a suction valve or reed member 39. Each valve assembly is operative in a conventional manner.

The valve assemblies 36 are each held in place in the end of a cylinder by means including a cap 40 retained in position by a spring 42, for example, a Belleville spring, and a retaining ring 44.

Provided on the crankcase are a pair of annular circular sealing flanges 48 and 50. These flanges are provided with recesses within which are disposed O-rings 52 and 54 for sealing between the annular sleeve 20 and the respective flanges 48 and 50. Defined between the exterior of the crankcase and the annular shell 20 is a space 56 into which discharge gases are passed from the cylinders 26 after compression. The discharge gases pass from the annular chamber 56 through a conduit (not shown) from the compressor to the condenser of the refrigerating system in a known manner. The annular space 56 is provided with a plurality of cavities to impart a muffiing effect to the discharge gases which are dis-charged from the cylinders into the space 56 prior to discharge from the compressor.

Suction gas enters the casing of the compressor via a suction line in a conventional manner and passes over the electric motor 68, thereby cooling the motor. The suction gas passes through the motor compartment into the suction and discharge valve assemblies 36 via passage means comprising an opening 69 in the partition 18 and an opening 70 in the discharge assembly 37. Thus, it is seen that the interior of the hermetic casing is substantially at suction pressure.

The motor 68 comprises a stator 72 which is mounted within the motor flange portion 16 of the compressor block or crankcase 15. The stator 72 is inductively connected to the rotor 74 which is afiixed onto the upper portion 76 of the crankshaft 30. The rotor may be suitably connected to the portion 76 of the drive shaft 30, as for example, by a key.

The shaft 30 may be journaled within a lower bearing 80 which is mounted in the lower bearing head 81. The lower bearing head 81 is maintained in position by a suitable wedge lock spring or retaining spring 82 seated within an annular groove in the compressor block 15. Also provided in the lower bearing head 81 is a thrust bearing 83, which has a central opening 84 defined therethrough. Located in the lower portion 85 of the crankshaft 30 adjacent the counterweight portion 86 is a coaxially dis posed hole 87 which constitutes the eye of the impeller or pump means which are defined within the crankshaft 30.

Such pump means are not part of the present invention and reference may be made to copending application Ser. No. 361,126, filed Apr. 20, 1964, now Patent No. 3,253,- 776 for a fuller explanation of the pump means. The pump means may comprise a vertically disposed passageway 90 in the crankshaft 30 which is offset from the axis of rota: tion of crankshaft 30 and is communicated with the eye 87 of the impeller by means of a transversely disposed passage 91 for feeding lubricant to the upper bearing means. Passage 91 may be opened at its ends to lubricate bearing 80. A second vertically disposed passage and a third verti- P11658111? pump.

cally disposed passage are provided in the crankshaft for supplying lubricant to a plurality of

ports

92, 93, 94 and 95 on the surface of the eccentric portion 29 of the crankshaft 30 for lubricating the connecting rod bearing surfaces. The second passage may be vented to the interior of the crankcase to function as a low pressure pump and the third pump is not vented, thereby functioning as a high A heat shield 31 may be provided about the annular sleeve 20 for minimizing heat transfer from the relatively hot discharge gases in the discharge gas muffiing chamber 56 to the relatively cold suction gas in the space between the compression means and the outer casing.

The upper bearing means comprise a first bearing and a second bearing 102 which are spaced from one another to define an annular space 103 therebetween and about the crankshaft.

The means for pressurizing the crankcase to positively displace lubricant therefrom during operation comprises a fan mechanism 105 operatively connected to the crankshaft 30 and rotatable therewith. The fan includes a cupshaped portion 106 enclosing an intermediate portion of crankshaft 30 and being afl'lXed thereto as for example, by collar 107 that is welded or otherwise aflixed to portion 106 of the fan and is rigidly joined to crankshaft 30, for example, by a press-fit, and an annular centrifugal fan housing 108 which is doughnut shaped and divided internally by a plurality of blades 110 to define a plurality of compartments 111a and 1111) within nular ring 112 is affixed to the compressor block 15 for minimizing recirculation of suction gas.

Each of the compartments 111:: within the housing 108 are provided with openings 114 in the top wall thereof for communicating with the suction gas passing over the motor 68. In operation, suction gas enters the compartments 111a through the inlet openings 114 and is discharged into the crankcase through the openings 116 in the bottom of each compartment. The fan functions as a pump means to force the suction gas into the crankcase in order to raise the pressure therein and positively force lubricant within the crankcase through the openings 88 and 88' back into the sump defined in the lower shell of the compressor.

It will be noted that the cup-shaped portion 106 of the fan mechanism 105 encloses the intermediate part of the crankshaft 30 and is spaced therefrom so as to define an annular space or passage 115. Refrigerant vapor and lubricant may be vented from pump passage 90 through passage. 104 and passage at start up to permit lubricant to reach all the upper bearing surfaces. Further, during operation, lubricant pumped upwardly to the upper bearing means by the pump 90 will be returned to the crankcase through the annular passage 115, fan means 105, and passage in partition 18. Lubricant passes through the passage 115 and enters the pump compartments 111b via radial 118 defined in the walls of the housing 108. Such lubricant will be discharged from the compartments 111b through the openings 116 in the bottom thereof and then returned to the crankcase via the passage 120 in partition or wall 18. The lubricant returned from the upper hearing means to the crankcase is in a path separate from the suction gas, which passes over the electric motor 68 to the suction side of the piston mechanism through opening 69.

This construction prevents undesirable entertainment of lubricant in the suction gas.

It will be noted that there are actually two pumps formed within the fan mechanism-one for gas and the other for lubricanLCompartments 111a act upon the suction gas and compartments 111b act upon the lubricant. The lubricant pump means within crankshaft 30 will operate wherever shaft 30 is rotated to lubricate the shaftbearing surfaces and the connecting rod bearing surfaces. In operation, lubricant can flow freely from the top of hearing 100 into passage 115 and be returned to the crankcase in a path isolated from suction gas flowing to the crankcase for pressurization thereof and to the piston means.

the housing 108. An an- There will be a more efficient return of lubricant from the upper bearing means to the crankcase.

The present compressor design may utilize a large supply of oil or lubricant to minimize the adverse effects of miscibility of the oil and refrigerant normally used in hermetic refrigerant compressors. By virtue of positively pressurizing the crankcase during operation, the level of lubricant n the crankcase may be reduced below the level of the compression mechanism and the flywheel portion of the drive shaft. There is less frictional drag on the crankshaft during operation and the watts input to the electric drive motor may be reduced. Further, the means for pressurizing the crankcase are independent of piston design and of load conditions. Such means are also independent of whether or not the compressor is provided with cylinder unloaders.

By this invention, a fan mechanism is provided on the crankcase for positively pressurizing the crankcase during operation by use of suction gas and for returning lubricant from the upper bearing means to the crankcase in a path isolated from the suction gases passing over the compressor electric drive motor to the compression mechamsm.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and therefore it is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

We claim:

1. In a reciprocating compressor comprising an outer casing, compression means including a compressor block defining a crankcase therein and an annular sleeve about said block, a vertically extending crankshaft journaled in said block, said block defining cylinder means, a piston reciprocatingly disposed in each cylinder means, means operatively connecting each said piston to said crankshaft, an electric drive motor carried by the block and being operatively connected to said crankshaft, said block and annular sleeve being partially submerged in lubricant in the sump formed in the lower portion of the outer casing, and pump means in the crankshaft for lubricating the crankshaft bearing surfaces and the connecting means bearing surfaces, lubricant being disposed in the crankcase when the compressor is idle, the improvement comprising fan means on said crankshaft for pressurizing the crankcase during operation to return lubricant from the crankcase to the sump so as to reduce the level of lubricant in the crankcase below the connecting means and each said piston to increase the operating efliciency of the compressor and reduce the electrical input to the electric drive motor.

2. A refrigerant compressor as in claim 1 wherein said fan means pumps suction gas into the crankcase for increasing the pressure therein.

3. In a refrigerant compressor comprising a sealed outer housing, compression mechanism in said housing and spaced from said outer housing to define an annular space therebetween, the lower part of the outer housing defining a sump for lubricant, said compression mechanism including a cylinder block defining a crackcase, the lower portions of said block being partially submerged in said lubricant in said sump, resilient means supporting said cylinder block in said housing, at least one cylinder in said block, a piston reciprocatingly disposed in said cylinder, a vertically extending crankshaft journaled in upper and lower bearing means in said block, said crankshaft having a flywheel portion thereon disposed in said crankcase, electric motor means supported on said block and affixed to the upper end of said crankshaft for driving same, means operatively connecting said crankshaft to said piston, and pump means in said crankshaft for lubrieating said upper and lower bearing means, lubricant being disposed in said crankcase when the compressor is idle above the flywheel portion of the crankshaft, the improvement comprising fan means on said crankshaft for pressurizing the crankcase independent of piston design, whereby in operation, lubricant will be displaced from the crankcase to the sump and the level of lubricant in said crankcase will be reduced below the flywheel portion of said crankshaft, thereby minimizing frictional drag of the crankshaft in the lubricant and reducing the power input to said electric motor means.

4. A refrigerant compressor as in claim 3 wherein said fan means includes separate means for pumping suction gas into said crankcase to pressurize same and for pumping lubricant vented from the pump means in the crankshaft back into the crankcase in a path separate from the suction gas.

5. A refrigerant compressor as in claim 3 wherein said fan means includes a cup-shaped portion cooperating with said crankshaft to provide passage therebetween and a fan housing portion, said pump means being vented to said passage, whereby, in operation lubricant pumped by said pump means may pass into said passage and into said fan housing portion and be returned to said crankcase in a path isolated from said suction gas.

6. A refrigerant compressor as in claim 3 wherein said electric motor is cooled by suction gas passing thereover, said fan means includes means for forcing suction gas into the crankcase to positively increase the pressure therein and displace lubricant within the crankcase to a level below the flywheel portion of the crankshaft.

7. A refrigerant compressor as in claim 6 wherein said fan means communicates with said pump means in said crankshaft for receiving lubricant from said pump means and passage means for returning lubricant to said crankcase disposed in said cylinder block and communicating with said fan means.

8. A refrigerant compressor as in claim 7 wherein said fan means includes a housing portion having a plurality of compartments defined therein, each having an inlet opening for receiving suction gas and an outlet opening communicating with said passage means for pumping suction gas into said crankcase.

9. A refrigerant compressor as in claim 8 wherein said fan means includes a cup-shaped portion spaced from said crankshaft to define a passage therebetween, said pump means being vented to said passage, said fan housing including at least one compartment which communicates with said passage, but does not have an inlet opening for receiving suction gas, said one compartment having an inlet opening for communicating said one compartment with said passage means in said compressor block, so that in operation, lubricant can be returned to said crankcase in a path isolated from the suction gas.

10. In a refrigerant compressor comprising an outer casing, compression means defining a crankcase therein, a vertically extending crankshaft journalled in said compression means, said crankshaft having a counterweight portion adjacent the lower end thereof, cylinder means in said compression means, a piston reciprocatingly disposed in each cylinder means, means operatively connecting each said piston to said crankshaft, said compression means being partially immersed in lubricant in the sump formed in the lower portion of the outer casing, and pump means in the crankshaft for lubricating the crankshaft bearing surfaces and the connecting means zbearing surfaces, the improvement comprising means rotatable with the crankshaft for positively pressurizing the crankcase during operation independent of piston bypass to reduce the level of lubricant in the crankcase below the connecting means, each said piston, and the counterweight portion of the crankshaft to increase the operating efficiency of the compressor and reduce the electrical input to the electric drive motor.

11. A' refrigerant compressor as in claim 10 wherein the crankshaft includes a counterweight portion adjacent the lower end thereof, said pressurizing means reducing thelevel of lubricant in the crankcase below the counterweight portion of the crankshaft.

12. In a refrigerant compressor comprising an outer casing, compression means defining a crankcase therein, a vertically extending crankshaft journalled in said compression means, said crankshaft having a counterweight portion adjacent the lower end thereof, cylinder means in said compression means, a piston reciprocatingly disposed in each cylinder means, means operatively connecting each said piston to said crankshaft, said compressi-on means being partially immersed in lubricant in the sump formed in the lower portion of the outer casing, and pump means in the crankshaft for lubricating the crankshaft bearing surfaces and the connecting means bearing surfaces, there being lubricant in the crankcase when the compressor is idle, the improvement comprising means rotatable with the crankshaft for displacing lubricant from the crankcase and returning same to the sump during operation to reduce the level of lubricant in the crankcase below the counterweight portion of the crankshaft.

References Cited UNITED STATES PATENTS 2,246,868 6/1941 Trask 230-206 3,008,628 11/1961 Gerteis et a1 230-206 X 3,229,901 1/1966 Parker 230206 ROBERT M. WALKER, Primary Examiner.

Claims

1. IN A RECIPROCATING COMPRESSOR COMPRISING AN OUTER CASING, COMPRESSION MEANS INCLUDING A COMPRESSOR BLOCK DEFINING A CRANKCASE THEREIN AND AN ANNULAR SLEEVE ABOUT SAID BLOCK, A VERTICALLY EXTENDING CRANDSHAFT JOURNALED IN SAID BLOCK, SAID BLOCK DEFINING CYLINDER MEANS, A PISTON RECIPROCATINGLY DISPOSED IN EACH CYLINDER MEANS, MEANS OPERATIVELY CONNECTING EACH SAID PISTON TO SAID CRANGSHAFT, AN ELECTRIC DRIVE MOTOR CARRIED BY THE BLOCK AND BEING OPERATIVELY CONNECTED TO SAID CRANKSHAFT, SAID BLOCK AND ANNULAR SLEEVE BEING PARTIALLY SUBMERGED IN LUBRICANT IN THE SUMP FORMED IN THE LOWER PORTION OF THE OUTER CASING, AND PUMP MEANS IN THE CRANDSHAFT FOR LUBRICATING THE CRANKSHAFT BEARING SURFACES AND THE CONNECTING MEANS BEARING SURFACES, LUBRICANT BEING DISPOSED IN THE CRANKCASE WHEN THE COMPRESSOR IS IDLE, THE IMPROVEMENT COMPRISING FAN MEANS ON SAID CRANKSHAFT FOR PRESSURIZING THE CRANKCASE DURING OPERATION TO RETURN LUBRICANT FROM THE CRANKCASE TO THE SUMP SO AS TO REDUCE THE LEVEL OF LUBRICANT IN THE CRANKCASE BELOW THE CONNECTING MEANS AND