HORIZONTAL SCROLL COMPRESSOR

Abstract: The motion of the orbiting scroll (18) is used to cause pumping of oil in a hermetic horizontal scroll compressor (10).

Description: This invention relates to a lubrication system in a hermetic horizontal scroll compressor. A hermetic scroll compressor is normally in a vertical orientation so that lubrication for the shaft and orbiting scroll bearings, anti-rotation device, thrust surfaces, etc. is, typically, supplied by a passive centrifugal pump incorporated into the drive shaft. Oil is drawn from a sump which is located at the bottom of the compressor shell and enters the pump through an orifice in the bottom of the shaft. The parts requiring lubrication are, normally, no more than about 30 cm (a foot) or so above the oil level of the sump so that a small increase in the oil pressure due to its radial acceleration is sufficient to supply the oil to the required locations. This relatively simple, passive lubrication system is a primary reason why hermetic scroll compressors are designed to operate in a vertical position. In this orientation, the compressor height-to-diameter ratio is generally two, or more. By comparison, a typical reciprocating compressor of the same capacity has a height-to-diameter ratio of approximately 1.5. For many applications, the height of the compressor is a primary factor because of packaging considerations. Very often, the height of an air conditioning, refrigeration or heat pump unit is more important than its width or depth. Accordingly, a distinct advantage could be realized if the scroll compressor could be designed to operate in a horizontal orientation. However, in changing the orientation of a hermetic scroll compressor from a vertical to a horizontal orientation, there are significant changes in the lubrication system and gas flow paths. The motor, crankcase, anti-rotation device and scroll members may extend below the level of the oil in the sump although it is not necessary that all of the members be exposed to the oil sump. The parts to be lubricated are located no more than a few cm (a few inches) above the sump as opposed to about 30 cm (a foot), or more, in a vertical unit but the drainage paths are shorter and over different parts. The oil sump blocks some normally used gas paths which are used in cooling the motor and removing entrained oil and some of the drainage paths can contribute to oil entrainment. In JP-A-59 60091 there is described a lubrication system in a hermetic horizontal scroll compressor according to the preamble of claim 1. Specifically, JP-A-59 60091 discloses a lubrication system comprising a piston bore in fluid communication with the oil sump of the compressor, a piston means reciprocatably located in the piston bore, and a lubrication distribution means in fluid communication with the piston bore for delivering oil to lubricate the orbiting scroll, the crankshaft and the bearings of the compressor, the piston means cooperating with the piston bore so as to thereby pumps oil from the sump to the lubrication distribution means. It is an object of the present invention to provide a lubrication system in a hermetic horizontal scroll compressor to reduce the overall height and the cubage of the compressor. It is an additional object of this invention to provide improved lubrication in a hermetic scroll compressor, the motion of the orbiting scroll being employed to drive a positive displacement lubrication pump. These objects, and others as will become apparent hereinafter, are accomplished by the present invention. To achieve these objects, the lubrication system of the invention is characterized by the features claimed in the characterizing portion of claim 1. Specifically, the invention provides a system having a fluid path means in the orbiting scroll between the piston bore and the lubrication distribution means and defining a discharge line in the orbiting scroll for supplying oil to the lubrication distribution means, the orbiting scroll coacting with the piston means to cause the piston means to reciprocate in the piston bore whereby, when the orbiting scroll is caused to orbit, the oil pumped from the sump flows from the piston bore into the fluid path means in the orbiting scroll. Advantageous embodiments of the invention are claimed in the subclaims. In preferred embodiments of the invention, the piston bore is formed in the crankcase or in the orbiting scroll. The scroll compressor is horizontally oriented which reduces the height by a half as compared to a vertical unit. Since the oil sump is no longer located at what is now an end, the length of the shell can be reduced by the amount necessary to define the sump and to accommodate the oil pickup tube carried by the crankshaft. Because the crankshaft is no longer acting as a centrifugal pump, the passages used to produce the centrifugal pumping can be simplified and/or eliminated making machining easier and less expensive. The oil pump is of the positive displacement type driven by the motion of the orbiting scroll with the inlet located below the liquid level of the oil sump. The pump is driven by, or is integral with, the orbiting scroll without increasing the diameter of the shell. Basically, the hermetic scroll compressor is located horizontally thereby permitting a length and cubage reduction corresponding to the oil sump of a vertical unit and , with the sump located such that the scroll and anti-rotation structure goes beneath the surface of the oil sump, the motion of the orbiting scroll is employed to drive a positive displacement lubrication pump. The lubricating pump pumps the oil to the interfaces between the anti-rotation device and the fixed and orbiting scroll, to the interface between the orbiting scroll and the crankcase and to the bearings supporting the crankshaft and the bushing between the crankshaft and orbiting scroll. Brief Description of the Drawings For a further understanding of the present invention, reference should now be made to the following detailed description thereof taken in conjunction with the accompanying drawings wherein: Figure 1 is an end view of a horizontal scroll compressor; Figure 2 is a sectional view taken along line 2-2 of Figure 1; Figure 3 is an enlarged view of the bottom portion of the orbiting scroll as viewed in Figure 2; Figure 4 A is a sectional view taken along line 4-4 of Figure 3; Figures 4 B-D sequentially represent the movement of the orbiting scroll and pump at 90° intervals starting at and returning to the Figure 4 A position; Figures 5 A-D illustrate a second embodiment of the invention in positions corresponding to Figures 4 A-D; Figure 6 illustrates a third embodiment of the invention in a position corresponding to that of Figure 4 C; and Figure 7 illustrates a fourth embodiment of the invention in a position corresponding to that of Figure 4 C. Description of the Preferred Embodiments In Figures 1 and 2 the numeral 10 generally designates a low side, horizontal hermetic scroll compressor including a shell 12 made up of end portions 12-1 and 3 which are welded or otherwise suitably joined to middle portion 12-2. Within shell 12 are fixed scroll member 16, orbiting scroll member 18, anti-rotation device 20 in the form of an Oldham ring or coupling, crankcase 30, crankshaft 32, rotor 34 which is secured to crankshaft 32 and stator 36, as is conventional. Additionally, crankshaft 32 is supported at one end by bearing 40 and is supported at the other end by bearing 42 as well as being connected to boss 18-1 of orbiting scroll 18 via a bushing, sliding block or any other suitable structure 44. The structure so far described is generally that of a vertical hermetic scroll placed horizontally. The first consequence of the changed orientation is the relocation of the oil sump 50 which causes portions of stator 36, crankcase 30, anti-rotation device 20, orbiting scroll 18 and fixed scroll 16 to be located, or potentially located, beneath the level of the oil sump although not necessarily directly exposed to the oil in sump 50. A second consequence is the elimination of the need for crankshaft 32 and/or an oil pickup tube (not illustrated) to extend into an oil sump defined by shell member 12-3. As a result, the shell member 12-3 can be placed closer to the end of crankshaft 32 thereby reducing the length of shell 12 and its cubage. Other consequences are changes in the coaction between bearings 40 and 42 with crankshaft 32 since they now bear the weight of the crankshaft 32 and its carried members on one side, the lowest point, and because the crankshaft 32 no longer needs to provide a centrifugal pumping force to the oil to cause it to be pumped. In a conventional anti-rotation device 20 of the Oldham coupling type, the Oldham coupling reciprocates with respect to the crankcase 30. Similarly, the orbiting scroll 18 reciprocates with respect to the Oldham coupling 20 but, since the Oldham coupling is also reciprocating at 90° with respect to the direction of reciprocation of the orbiting scroll 18, the net result is an orbiting motion of orbiting scroll 18 with respect to fixed structure in shell 12 such as fixed scroll 16. The motion of the orbiting scroll can be adopted to drive a positive displacement pump according to the teachings of the present invention. Referring specifically to Figures 2, 3 and 4 A-D, it will first be noted that the lower portion of the orbiting scroll 18 has been removed to provide a flat surface 18-2. An enlarged passage 18-3 is formed in orbiting scroll 18 at surface 18-2 and the enlarged passage 18-3 transitions into a smaller radial bore 18-4. Flat surface 18-2 is engaged by piston 22 which is spring biased into engagement by spring 23. Hollow piston 22 reciprocates in bore 24-1 in piston cylinder 24 which, as illustrated in Figure 3, is a part of crankcase 30 but which can be a separate part which is welded or otherwise suitably secured to the interior of shell 12 as illustrated in Figures 4A-D. The only differences between Figure 3 and Figures 4A-D is that in Figure 3 the piston cylinder is part of crankcase 30 whereas it is a separate piece welded in place in Figures 4A-D. The coactions are exactly the same. However, if desired bore 24-1 could also be rectangular in cross section with crankcase 30 forming one side. As best shown in Figure 3, bore 24-1 is always in fluid communication with oil sump 50 via fluid diode 26 which defines the suction inlet and bore 30-1 which extends through crankcase 30 into cylinder 24. Hollow piston 22 has a fluid diode or flow port 28 located in the piston head such that fluid diode or flow port 28 registers with enlarged passage 18-3 in some combinations of positions of the piston 22 and orbiting scroll 18. Referring now to Figures 4 A-D, it should first be noted that the point P which is located at an intersection of enlarged passage 18-3 and surface 18-2 traces a circle which is shown in phantom and which represents the orbiting path of orbiting scroll 18. Starting with Figure 4 A, orbiting scroll 18 is at its lowest point, representing the end of a discharge stroke/start of a suction stroke, surface 18-2 is blocking fluid diode or flow port 28, and the volume within bore 24-1 and piston 22 is at a minimum. As orbiting scroll 18 moves from the Figure 4 A to the Figure 4 B position, spring 23 maintains piston 22 engaged with surface 18-2 which still blocks fluid diode or flow port 28, the volume within bore 24-1 and piston 22 is increasing so that oil is drawn into bore 24-1 from oil sump 50 via fluid diode 26 and line 30-1. As orbiting scroll 18 goes from the Figure 4 B to the Figure 4 C position, the volume within bore 24-1 and piston 22 continues to increase such that Figure 4 C represents the end of the suction stroke and the beginning of the discharge stroke. As orbiting scroll 18 goes from the Figure 4 C to the Figure 4 D position, fluid diode or flow port 28 becomes uncovered and the volume within bore 24-1 and piston 22 is decreased so that oil is forced through fluid diode or flow port 28 into enlarged passage 18-3. There can be some flow through fluid diode 26 towards oil sump 50 but because of the increased resistance to flow through fluid diode 26 in that direction, most of the flow from bore 24-1 and piston 22 will be through fluid diode or flow port 28. As orbiting scroll 18 goes from the Figure 4 D to the Figure 4 A position, the volume within bore 24-1 and piston 22 continues to decrease and oil is discharged through fluid diode or flow port 28 until the Figure 4 A position is reached and the cycle is repeated. Because surface 18-2 covers fluid diode or flow port 28 in a valving action, it is not necessary that 28 be a fluid diode. Referring now to Figure 2, radial bore 18-4 intersects with one end of axial bore 18-5 and terminates at axial bore 18-6. The other end of axial bore 18-5 terminates at annular groove 30-2 which faces orbiting scroll 18. Annular groove 30-2 has an enlarged portion which is always in fluid contact with bore 18-5 as orbiting scroll 18 orbits and is of a size corresponding to the circle of orbit. Axial bore 30-3 extends from the enlarged portion of annular groove 30-2 to radial bore 30-4. Radial bore 30-4 terminates at radial bore 42-1 which extends through bearing 42. Axial bore 18-6 terminates in axial bore 32-1 which contains bushing or sliding block 44. Axial bore 32-1 is connected to axial bore 32-3 through an enlarged counter-bored portion 32-2 whose diameter corresponds in size to the circle of orbit so as to maintain bores 18-6 and 32-3 in continuous fluid communication. Axial bore 32-3 is formed in crankshaft 32 and extends for its length. Bore 32-3 is connected to bearing 40 via radial bore 32-4. In operation, orbiting scroll 18 orbits due to its coaction with Oldham coupling 20. As orbiting scroll 18 orbits, piston 22 coacts with bore 24-1 as described above with respect to Figures 4 A-D, drawing oil from the sump 50 via fluid diode 26 and bore 30-1 and discharging it via fluid diode or flow port 28 into enlarged passage 18-3 and then radial bore 18-4 at an elevated pressure which is sufficient to feed the oil to any place in the shell 12 without requiring a further pressure boost. Specifically, bore 18-4 is fluidly connected via axial bore 18-5 to the enlarged portion of annular groove 30-2 at the interface between orbiting scroll 18 and crankcase 30. The pressure of the oil is sufficient to fill groove 30-2 and thereby provide lubrication between the orbiting scroll 18 and crankcase 30. Oil supplied to groove 30-2 also flows into bore 30-3 and passes via bores 30-4 and 42-1 into the interface between bearing 42 and crankshaft 32 which fills with oil and provides lubrication between bearing 42 and crankshaft 32. A portion of the oil supplied to bore 18-4 is supplied to bore 32-1 via bore 18-6. The cavity defined by bore 32-1 of crankcase 32 contains boss 18-1 of orbiting scroll 18 and bushing or sliding block 44 which are lubricated by the oil supplied to bore 32-1. A portion of the oil supplied to bore 32-1 is supplied to bearing 40 via counter-bore 32-2, bore 32-3 and bore 32-4. Since the oil is only being pumped several inches, there is no need for a centrifugal boost. Figures 5 A-D illustrate a modified pump structure where the pump is carried by the orbiting scroll 180 so that piston 122 slides on the surface 124-1 of oil supply housing 124. All unmodified structure has been numbered the same as in the embodiment of Figures 2-4. The interior chamber 124-2 of oil supply housing 124 is in fluid communication with oil sump 50 through one or more ports 124-3 and establishes fluid communication with bore 180-3 and the interior of piston 122 via discharge port 124-4 and fluid diode or flow port 126 in the head of piston 122. As in the case of the embodiment of Figures 2-4, the fluid diode or fluid port 126 in the head of the piston is covered during the discharge stroke during each orbit of the orbiting scroll and contact between the piston 122 and surface 124-1 is due, at least in part, to the spring bias of spring 23. Although the orbiting scroll 180 is illustrated as fully circular, a flattened surface such as 18-2 of Figure 4 can be provided. Figures 5 A-D correspond to Figures 4 A-D as to their crank and stroke positions. Figure 5 A represents the transition between discharge and suction. The volume in bore 180-3 and piston 122 is at a minimum and piston 122 is held in sliding engagement with surface 124-1 by spring 23 at a position where fluid diode or flow port 126 is just about to register with port 124-4. In going from the Figure 5 A to the Figure 5 B position, fluid diode or flow port 126 comes into registration with port 124-4 and the volume in bore 180-3 and piston 122 increases so that oil is drawn from sump 50 and serially flows through port(s) 124-3, chamber 124-2, port 124-4, and fluid diode 126 into the interior of bore 180-3 and piston 122. It should be noted that fluid diode or flow port 126 in piston 122 defines a suction inlet whereas fluid diode 28 in piston 22 defines a discharge outlet. Fluid diode 128 in radial bore 18-4 minimizes any reverse flow into bore 180-3 and piston 122 from the lubrication distribution lines. In going from the Figure 5 B to the Figure 5 C position, fluid diode or flow port 126 moves out of registration with port 124-4 completing the suction stroke and the volume within bore 180-3 and piston 122 is at its maximum. In going from the Figure 5 C to the Figure 5 D position, the discharge stroke starts forcing oil from the interior of bore 180-3 and piston 122 through discharge diode 128 into line 18-4 from which it is distributed as described above with respect to Figure 2. Because fluid diode or flow port 126 is covered by surface 124-1, the resistance to reverse flow by fluid diode or flow port 126 plus the blocking of fluid diode or flow port 126 essentially eliminates any reverse flow as the volume in bore 180-3 and piston 122 decreases during the discharge stroke. Alternatively, because of this valving action between surface 124-1 and flow port 126, port 126 does not have to be a fluid diode. In going from the Figure 5 D to the Figure 5 A position, the discharge stroke goes to completion and the cycle repeats. Referring now to Figure 6, the piston 222 is in a position corresponding to that of Figures 4 C and 5 C where the transition from suction to discharge takes place. This embodiment eliminates the need for spring 23. Piston 222 includes an enlarged head 222-1 which is guidingly received by piston guide 224 such that piston 222 slides in piston guide 224 and bore 280-3 in accordance with the orbiting motion of orbiting scroll 280. This embodiment requires that shell 212 has a flattened portion or a flat bottomed depression to accommodate the linear, transverse coaction between head 222-1 and piston guide 224. Oil from sump 50 is drawn into the interior chamber 222-3 of piston 222 fluid diode 226 during the suction stroke and passes from bore 280-3 through fluid diode 228 into radial bore 18-4 during the discharge stroke. Oil delivered to radial bore 18-4 is distributed as described with respect to Figure 2. The embodiment of Figure 7 is similar to that of Figure 6 except a spring bias is used rather than a piston guide and piston head 322-1 is rounded to complement the interior of shell 312. The piston 322 is in a position corresponding to that of Figures 4 C and 5 C where the transition from suction to discharge takes place. Piston 322 is held in sliding contact with shell 12 by spring 23 as piston 322 is carried by the orbiting scroll 380 during its orbiting motion. Oil from sump 50 is drawn into the interior chamber 322-3 of piston 322 via fluid diode 326 during the suction stroke and passes from bore 380-3 through fluid diode 328 into radial bore 18-4 during the discharge stroke. Oil delivered to radial bore 18-4 is distributed as described with respect to Figure 2.

Claims: A lubrication system in a hermetic horizontal scroll compressor including a shell (12) containing a fixed scroll (16) and an orbiting scroll (18), a crankcase (30), a crankshaft (32), bearings (40,42) for supporting said crankshaft (32), means (34,36) for driving said crankshaft (32), an anti-rotation means (20) for limiting said orbiting scroll (18) to orbiting motion and an oil sump (50), said lubrication system comprising: a piston bore (24-1; 180-3; 280-3; 380-3) in fluid communication with said oil sump (50), a piston means (22; 122; 222; 322) reciprocatably located in said piston bore (24-1; 180-3; 280-3; 380-3), a lubrication distribution means (18-4) in fluid communication with said piston bore (24-1; 180-3; 280-3; 380-3) for delivering oil to lubricate said orbiting scroll (18), said crankshaft (32) and said bearings (40,42), said piston means (22;122;222;322) cooperating with said piston bore (24-1; 180-3; 280-3; 380-3) so as to pump oil from said sump (50) to said lubrication distribution means (18-4), characterized by a fluid path means (18-3; 128; 228; 328) in said orbiting scroll (18) between said piston bore (24-1; 180-3; 280-3; 380-3) and said lubrication distribution means (18-4) and defining a discharge line in said orbiting scroll (18) for supplying oil to said lubrication distribution means (18-4), said orbiting scroll (18) coacting with said piston means (22; 122; 222; 322) to cause said piston means (22;122;222;322) to reciprocate in said piston bore (24-1; 180-3; 280-3; 380-3) whereby, when said orbiting scroll (18) is caused to orbit, the oil pumped from said sump (50) flows from said piston bore (24-1; 180-3; 280-3; 380-3) into said fluid path means (18-3; 128; 228; 328) in said orbiting scroll (18). The lubrication system of claim 1, characterized in that said piston bore (24-1) is formed in said crankcase (30). The lubrication system of claim 1, characterized in that said piston bore (180-3; 280-3; 380-3) is formed in said orbiting scroll (18). The lubrication system of claim 1, characterized in that said piston bore is a vertically extending radial piston bore (24-1) formed in said crankcase (30) and which extends upwardly from said shell (12), a further fluid path means (30-1) being provided between said oil sump (50) and said piston bore (24-1) and defining a suction supply line for supplying oil to said piston bore (24-1), said lubrication distribution means (18-4) including means (18-5; 30-2) for supplying oil to provide lubrication between said orbiting scroll (18) and said crankcase (30). The lubrication system of claim 1, characterized that said piston bore is a vertically extending radial piston bore (180-3; 280-3; 380-3) formed in said orbiting scroll (18) and which extends upwardly form said shell (12), a further fluid path means (124-4; 226; 326) being provided between said oil sump (50) and said piston bore (180-3; 280-3; 380-3) and defining a suction supply line for supplying oil to said piston bore, said lubrication distribution means (18-4) including means (18-5; 30-2) for supplying oil to provide lubrication between said orbiting scroll (18) and said crankcase (30).

Inventors: DEBLOIS, RAYMOND LEON, FRASER, HOWARD HENRY, JR., MCFARLIN, DAVID JAMES, STOEFFLER, RICHARD CLARK
Applicants: CARRIER CORPORATION
Application year: 1990
Main classification: F04C29
IPC codes: F04C18, F04C29