MXPA00010452A - Scroll machine - Google Patents

Abstract

A scroll compressor has an orbiting scroll which has an end plate with a hub extending generally perpendicular from the end plate. The hub defines a bore within which a bearing is press fit. The machining of the bore in the hub is done in a conical manner to accommodate and compensate for the unequal distortion of the hub between the two ends of the hub. The conical shape and the unequal distortion provide an assembled bearing with a more cylindrically shaped inner surface.

Description

BALL FOR CONICAL BUSH FOR SPIRAL MACHINE DESCRIPTION OF THE INVENTION The present invention relates to spiral machines. More particularly, the present invention relates to scroll compressors having a conical hole in the bushing into which the bearing is pressed. After inserting the bearing, the conical shape of the hole together with the variation in bushing distortion provides a straight bearing for the compressor. Spiral-type machines are becoming more and more popular for use as compressors in both refrigeration and air-conditioning applications due mainly to their extremely efficient operating capacity. Generally, these machines incorporate a pair of geared coil windings one of which is orbited against the other to define one or more mobile cameras that progressively decrease in size as they move from an external suction port to a port. central discharge. An electric motor is provided which operates to activate the orbiting scroll member by means of a suitable driving shaft fixed to the rotor of the motor. In a hermetic compressor, the bottom of the hermetic cover usually contains an oil collector for lubrication and cooling purposes.

Generally, the motor includes a stator that is secured to the compressor cover. The motor rotor rotates inside the stator to transfer rotation to the crankshaft which is normally adjusted under pressure inside the motor rotor. The crankshaft is rotatably supported by a pair of bearings that are supported by an upper bearing housing and a lower bearing housing. The crankshaft includes an eccentric journal which extends into a defined bore in a spiral or distant bushing. Arranged between the hub of the crankpin and the inner surface of the hole is a transmission bushing that moves against a bearing that is press fit into the hole in the bushing. The orbiting spiral bushing extends perpendicularly from a base plate of the orbiting scroll. The bushing hole extends from the open end of the bushing to a position generally adjacent to the base plate of the orbiting scroll. In this way, the hole in the bushing is a blind hole with the open end being placed at the distal end of the bushing and the closed end being placed on the base plate of the orbiting scroll. During the manufacture of the orbiting coil, the hole in the hub is machined and the bearing is snapped into the machined hole. Due to the ratio of adjusting the bearing pressure and the hole, both the spiral bushing and the bearing will deform during the bearing assembly. The amount of total deflection will be determined by the total hardness of the bushing. The deflection of the bushing at the open end of the hole will be greater than the deflection of the bushing at the closed end of the hole. The main reason for this uneven deflection is because the bushing at the open end of the orifice is not supported while the bushing at the closed end of the orifice is supported by the endplate. Uneven deflection will result in an assembled bearing having a larger diameter at the open end than the closed end. This tapering bearing will adversely affect the long-term performance of the bearing life and thus of the stretching machine. The present invention presents a solution to the problem of tapered bearing by providing a craft of conical bearing before installing the bearing. The conical shape of the bearing bore provides a smaller diameter at the open end and a larger diameter at the closed end. After assembling the bearing, the uneven deflection of the spiral bushing will provide an assembled bearing that is more cylindrical than the prior art systems. In this way, the Cylindrical shape will have a higher performance in this way increasing the long term durability of both the bearing and the compressor. The more cylindrical shape increases durability by providing a uniform clearance between the bearing and the sleeve. The uniform clearance increases the bearing capacity of the bearing because more uniform pressures are being exerted on the bearing. Other advantages include if a more uniform pressure load is required to assemble the bearing and this load under uniform pressure provides a better indication of the clamping pressure of the assembly. further, the system of the present invention is less sensitive to the dimensional variations of the individual components and this will therefore allow some extension of the tolerances of the individual dimensions. Other advantages and objects of the present invention will be apparent to those skilled in the art from the following detailed description, claims and appended drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, which are illustrated in better mode currently contemplated to carry out the present invention: Figure 1 is a vertical sectional view through the center of the spiral type refrigeration compressor incorporating the bearing conical bushing according to the present invention; Figure 2 is an enlarged view of the orbiting spiral bushing and compressor bearing mixed in Figure 1; Figure 3 is an enlarged sectional view of the orbiting scroll bushing shown in Figures 1 and 2 before assembling the bearing illustrated in conical bushing hole in accordance with the present invention; Figure 4 is an enlarged sectional view similar to Figure 3 but illustrating a tapered bushing hole according to another embodiment of the present invention; and Figure 5 is an enlarged sectional view similar to Figure 3 but illustrating a tapered vessel orifice according to another embodiment of the present invention. Referring to the drawings, in which similar reference numerals designate the corresponding or similar parts in the different views, a spiral compressor incorporating a compensation system according to the present invention is shown in FIG. is generally designated by the reference numeral 10. The compressor 10 comprises a generally cylindrical sheath 12 which is welded at the top end thereof a cover 14 and at the lower end thereof a base 16 having a plurality of feet assembly (not shown) integrally formed therewith. The lid 14 is provided with a refrigerant discharge fitting 18 which may have a usual discharge valve therein (not shown). Other main elements fixed to the cover include a transversely extending partition 22, which is welded around its periphery at the same point as the cover 14 is welded to the cover 12, a main bearing housing 24 is suitably secured to the cover 12 by a plurality of legs extending radially outwardly and a lower bearing housing 26 also having a plurality of legs extending radially outwardly each of which is also suitably secured to cover 12. A stator 28 The motor generally has a square or hexagonal cross section but with the rounded corners press fit into the cover 12. The flat portions between the rounded corners of the stator 28 provide passages between stator 28 and cover 12, which facilitate flow return the lubricant from the top of the cover to the bottom. A driving shaft or crankshaft 30 having an eccentric journal 32 at the upper end thereof is rotatably articulated in a bearing 34 in the housing 24 of the main bearing and a second bearing 36 in the lower bearing housing 26. The crankshaft 30 has at the lower end a concentric orifice 38 with a relatively large diameter communicating with a small diameter orifice 40 inclined radially outwardly extending upwards thereof towards the upper part of the crankshaft 30. Placed inside the orifice 38 is an agitator 42. The lower portion of the inner cover 12 defines an oil collector 44 which is filled with lubricating oil to a level slightly above the lower end and of a rotor 46, and an orifice 38 acts as a pump for pumping the lubricating fluid towards the crankshaft 30 and into the orifice 40 and finally to all the different portions of the compressor that require lubrication. The crankshaft 30 is rotatably activated by the electric motor including a stator 28, windings 48 passing therethrough and a rotor 46 which is press fit into the crankshaft 30 and which has upper and lower counterweights 50 and 52, respectively. The upper surface of the main bearing housing 24 is provided with a flat bearing surface 54 on which is placed an orbiting scroll member 56 having the winding 58 or conventional spiral blades extending upwardly from the end plate 60. . Projecting towards down from the inner surface of the end plate 60 the orbiting orbital member 56 encounters a cylindrical bushing having a bearing 62 hinged therein and in which a drive bushing 64 having an inner bore 66 in the bushing is rotatably disposed therein. whereby a crankpin 32 is activated. The crankpin 32 has a plane on a surface which actively engages a flat surface (not shown) formed in a portion of the orifice 66 to provide a radially subordinate activation arrangement., as the one shown in the North American Patent 4,877,382 of the attorney, the description of which is incorporated herein by reference. Also provided is an Oldham coupling, positioned between the orbiting spiral member 56, the bearing housing 24 and keyed to the orbiting spiral member 56 and a non-orbiting spiral member 70 to prevent rotary movement of the orbiting scroll member 56. The Oldham coupling 68 is preferably of the type described in co-pending US Patent 5,320,506, the disclosure of which is incorporated herein by reference. The non-orbiting scroll member 70 is also provided by including a winding 72 extending downwardly from an end plate 74 which is placed in gear engagement with the winding 58 of the orbiting scroll member 56. The non-orbiting spiral member 70 has a centrally disposed discharge passage 76 which communicates with an upwardly open notch 78 which in turn is in fluid communication with an exhaust silencer chamber 80 defined by the cover 14 and the division 22. An annular notch 82 is also formed in the non-orbiting spiral member 70 into which a seal assembly 84 is placed. The notches 78 and 82 and the seal assembly 84 cooperate to define the axial pressure destabilizing chambers that receive the pressurized fluid that is being compressed by the windings 58 and 72 so as to exert a desired axial force on the member 70 in this spiral not orbiting to thereby push the tips of the respective windings 58, 72 to enter sealed engagement with the opposite end plate surfaces of the end plates 74 and 60, respectively. The seal assembly 84 of preference is of the type described in detail in U.S. Patent No. 5,156,539, the disclosure of which is incorporated herein by reference. The non-orbiting scroll member 70 is designed to be mounted in the bearing housing 24 in a suitable manner such as that described in US Patent No. 4,877,382, or US Patent No. 5,102,316, the aforementioned description of which they are incorporated herein by reference. Referring to Figures 2 and 3, the bushing of the orbiting scroll member 56 includes an annular wall 90 which extends generally and perpendicularly from the end plate 60. The annular wall 90 defines an internal bore 92 within which the bearing 62 is located. The manufacturing process for the orbiting spiral member 56 includes machining the bore 92 and the bearing assembly 62 within the bore 92. The dimensions for the orifice 92 and the dimensions for the bearing 62 are chosen so that an interference fit occurs between the outer diameter of the bearing 62 and the inner diameter of the hole 92. Typically, the amount of interference designed in the assembly is 0.007 cm (. 003 inches) when the spiral member 56 of the bearing 62 is made from steel. Of course, the amount of interference will change when the spiral member 56 is made of a different material. These dimensions are typical for an orifice diameter of approximately 30 mm for the orifice 92. During the assembly of the bearing 62 within the hole 92, both the annular wall 90 and the bearing 62 will deviate due to the interference fit. Typically, a steel or cast iron spiral member 56 will see an annular wall 90 deviating outwardly about 40% of the interference and the bearing 62 will deviate inward approximately 60% of the interference. The ratio between the amount of deflection will change when the spiral member 56 is made from a different material. Referring to Figure 3, hole 92 is illustrated. Hole 92 includes a first diameter 96 at its open end and a second diameter 98 at its closed end. The shape of the hole 92 between the diameters 96 and 98 is a straight line relationship and the diameter 96 is smaller than the diameter 98. Preferably, the difference between diameter 96 and diameter 98 between .0025 cm and .0030 (.0010 inches and .0012 inches). Referring to Figure 4, an orifice 92 'is illustrated. The hole 92 'includes a first diameter 96' at its open end and a second closed-end diameter 98 '. At the end of the orifice 92 'between the diameters 96' and 98 'is defined by the diameter 96' which extends towards the diameter 98 'by a specific distance and then a straight line relationship as shown by the solid line or a ratio curve as shown with the dotted line between the diameters 96 'and 98'. The diameter 96 'is smaller than the diameter 98'. Preferably, the difference between the diameters 96 'and the diameter 98' is between .0015 cm and .0030 cm (.006 inches and .0012 inches), with the diameter 96 'extending approximately 60% to the length between the end free and the closed end of the orifice 92 '. Referring now to Figure 5, hole 92 is illustrated. "Hole 92" includes a first diameter 96"at its open end and a second diameter 98" at its closed end. The shape of the orifice 92"between the diameters 96" and 98"is a curved line or an arcuate surface and the diameter 96" is smaller than the diameter 98. Preferably, the difference between the diameters 96"and 98" is between .0015 cm and .0025 cm (.0006 inches and .0010 inches) While the description detailed above describes the preferred embodiments of the present invention, it should be understood that the present invention is susceptible to modifications, variations and alterations without depart from the scope and fair meaning of the appended claims.

Claims (18)

1. CLAIMS 1. A spiral machine characterized in that it comprises: a cover; a first spiral member positioned within the cover, the first spiral member having a base plate and a first spiral winding extending from the first base plate; a second spiral member placed inside the cover, the second spiral member has a second spiral winding, the second spiral winding is engaged with the first spiral winding; a driving member for causing the spiral members to orbit in relation to one another whereby the spiral coils create pockets of progressively changing volume between a suction pressure zone and a discharge pressure zone; a hub extending from the base blade of the first spiral member, the hub defines a hole into which the driving member is placed, the hole has a first diameter located adjacent to the base plate and a second diameter located away from the base plate; and a bearing positioned within the bore of the bushing in a snap-fit relationship with the bushing, the first diameter of the hole is larger than the second diameter of the hole before the ball bearing is press fit into the hole.
2. 2. The spiral machine according to claim 1, characterized in that the hole increases in size between the second diameter and the first diameter in a generally linear manner.
3. 3. The spiral machine according to claim 1, characterized in that the second diameter of the hole extends within the hole by a specific distance.
4. 4. The spiral machine according to claim 3, characterized in that the specific distance is 60% the distance between the first and second diameter.
5. 5. The spiral machine according to claim 3, characterized in that the orifice increases in size between the first diameter and the second diameter in a generally linear manner.
6. The spiral machine according to claim 1, characterized in that the hole increases in size between the first diameter and the second diameter in a generally arched manner.
7. 7. A spiral member characterized in that it comprises: a base plate having a first side and a second side; a spiral winding extending from the first side of the base plate; and a bushing extending from the second side of the base plate, the bushing defines an orifice, the hole has a first diameter located adjacent to the base plate and a second diameter located away from the base plate, the first diameter is greater than the second diameter.
8. 8. The spiral machine according to claim 7, characterized in that the orifice increases in size between the first diameter and the second diameter in a generally linear manner.
9. 9. The spiral machine according to claim 7, characterized in that the second diameter of the orifice extends within the hole by a specific distance.
10. The spiral machine according to claim 9, characterized in that the specific distance is sixty percent of a distance between the first and second diameters.
11. 11. The spiral machine according to claim 9, characterized in that the orifice increases in size between the first diameter and the second diameter in a generally linear manner.
12. The spiral machine according to claim 7, characterized in that the orifice increases in size between the first diameter and the second diameter in a generally arcuate manner.
13. 13. A method for manufacturing a spiral member having a press fit bearing with a bushing hole, the method comprising: machining the hole in the bushing to a first diameter dimension at a first end of the hole and a second diameter dimension at the second end of the hole, the first diameter dimension is greater than the second diameter dimension; and Press the bearing into the hole so that the deflection of the bushing in the first diametric dimension is less than the deflection in the second diameter dimension.
14. 14. The method according to the claim 13, characterized in that the step of machining the hole in the hub machines, the hole is such that the hole extends generally linearly between the first and second end.
15. 15. The method of compliance with the claim 13, characterized in that the step of machining the hole in the bushing machines the second diameter dimension by a specific distance from the hole.
16. 16. The method according to claim 15, characterized in that the specified distance is sixty percent of a dimension between the first end and the second end.
17. The method according to claim 15, characterized in that the step of machining the hole in the bushing machines the holes so that the hole extends generally linearly between the specific distance of the hole and the first end.
18. 18. The method according to claim 13, characterized in that the step of machining the hole in the bushing machines the hole so that the hole extends arcuately between the first and the second end.