ES2905687T3 - spiral type machine - Google Patents

Abstract

A scroll type displacement machine adapted to move a working fluid between a low pressure environment and a high pressure environment, the scroll type displacement machine comprising: a casing (80); a pair of scrolls comprising an orbital scroll (30) and a fixed scroll (20), said fixed and orbital scrolls having respective scroll vanes (22, 32) that fit together; an Oldham ring means (50) coupled to said fixed and orbital scrolls (20, 30) to prevent rotation of said orbital scroll (30) but allowing said orbital scroll (30) to enjoy orbital motion about an axis of said fixed spiral (20); a rotary drive shaft (71) having an axis of rotation and adapted for rotary movement about said axis of rotation; bearing means (67) supporting said rotary drive shaft (71) within said housing and allowing said rotary drive shaft to enjoy rotary motion within said housing; an eccentric drive bearing means (45) located on said drive shaft, adjacent said pair of scrolls, and operatively coupled to said orbital scroll (30) such that rotation of said drive shaft corresponds to orbital motion of said orbital spiral; said housing enclosing at least said eccentric drive bearing means (45), at least a portion of said pair of scrolls (20, 30) and at least a portion of said rotary shaft (71); said fixed scroll (20) having a low pressure port (21) located in a radially outer portion of the scroll blade (22) thereof and in communication with said low pressure environment; said orbital scroll (30) having a high pressure port (39) disposed in a radially central portion of the scroll blade (32) thereof; and an internal pathway coupled to the high pressure port (39) resulting in said high pressure environment being located within said casing, and characterized in that the high pressure port (39) is located, relative to to said eccentric drive bearing means (45), such that high pressure fluid passes directly from the high pressure port, over said eccentric drive bearing means (45) and thence through of a flow path, to said interior of said housing (80), whereby fluid flow serves to pass first over the drive bearing means and at least one adjacent surface (36) of said orbital scroll ( 30).

Description

DESCRIPTION

spiral type machine

field of invention

The present invention generally relates to scroll type displacement machines adapted as compressor, expander (pneumatic motor), liquid pump or hydraulic motor. More particularly, according to one aspect, the present invention relates to so-called high-side machines, in which the compressor mechanism within the casing is surrounded by a high-pressure working fluid. According to another aspect, the present invention relates to a unique internal drive system arrangement that simplifies the manufacture of the scroll-type machine and allows easy adaptation to various types of motor (i.e., compressor or pump) or to various power transfer devices (ie expander or motor). According to a further aspect, the present invention relates to such a machine which uses an Oldham coupling (or ring) to prevent rotation of the orbital scroll with respect to the fixed scroll. According to yet another aspect, the present invention relates to hermetic or semi-hermetic compressors in which the motor and the compressor are sealed within an enclosure containing the working fluid to be compressed.

Background of the invention

Scroll type scroll machines are commonly used as compressors for various gases, including air and refrigerants. However, they are easily adapted for use as a compressed vapor expander (for example, an air motor), liquid pump, or hydraulic motor. During normal operation, scroll-type machines exhibit high pressure in the central region of the pair of scrolls and low pressure around the outer periphery. Fluid flows from outside to inside in compressors and pumps and from inside to outside in expanders and motors.

In the case of so-called low-side machines, where the casing containing the scroll mechanism contains working fluid at a low pressure level, means are provided to isolate the high pressure fluid passing through the port. pressure from the fixed scroll, sometimes through a simple discharge tube connected to the fixed scroll and, more commonly, through a high pressure or pulsating volume manifold integrated into the external casing and also communicated externally through a high pressure pipe or fitting.

As for the so-called high-side machines, the low pressure flow is directly connected to the scroll pair at the periphery and the high pressure flow exits through the center of the scroll pair and passes through an outer casing containing the pressurized flow. The high pressure flow serves to cool bearings and any other components that generate heat, such as motors or sliders. The orbital scroll normally has a drive bearing located in the center of the scroll on the opposite side of the helical blades. To isolate this drive system from direct fluid flow, the high pressure port is generally located in the center of the stationary scroll, on the side of the scroll set opposite the drive bearing. The fixed scroll high pressure port communicates directly with the interior of the outer casing. In such an arrangement, means are provided for the flow to pass around the set of scrolls and communicate between the discharge port on one side of the set of scrolls and the rest of the outer casing on the other side. This can take the form of an enlarged outer casing or a special gas passage means to transport the fluid. These options represent somewhat increased size and weight for the overall compressor assembly, along with the attendant manufacturing complications. US2004/101428 A1 discloses a fluid scroll type machine having a high pressure port located in a radially central portion of the orbital scroll and isolated from the drive bearing by a tubular seal.

Consequently, one aspect of the invention is aimed at improving the state of the art in regard to the high-pressure fluid path in a high-side machine in order to avoid the disadvantages associated with driving a high-pressure working fluid. pressure between a high pressure port of the stationary scroll and the external casing of the compressor.

In all of these configurations, a drive shaft, which is used to apply or extract mechanical power, is provided with support bearing means to support radial loads and allow free rotation of the drive shaft. Interposed between the drive shaft and the orbital scroll is an eccentric drive bearing which may take the form of an eccentric bearing, a so-called sliding block, or an eccentric bushing, all of which serve to provide an eccentric drive for the connection between the shaft drive and the orbital scroll and drive the orbital scroll in a circular path, that is, a circular orbit without rotation. The eccentric drive bearing may take the form of a bearing rigidly fixed to the drive shaft and driving the orbital scroll through a fixed orbital radius, or it may take the form of a so-called radially adaptive drive in which the radial position of the orbital scroll relative to the center of the drive shaft may vary in response to misalignment and tolerance variations, in order to maintain positive contact between the orbital scroll vane walls and the stationary scroll at all times.

Additionally, an arrangement of counterweights is provided to achieve a dynamic balance between the various orbiting, rotating, and translating masses within the machine. Typically, a primary counterweight closer to the orbital scroll provides the machine with static balance. However, the axial separation between the unbalance planes of the moving components and the plane of action of the primary counterweight results in an overturning moment that tends to impose a wobble-type load on the axle and, consequently, on the frame. of the compressor, which generates undesirable vibrations. To counteract this dynamic imbalance, a secondary counterweight is provided towards the end of the shaft opposite the orbital scroll (on the other side of said primary counterweight) to create a compensating overturning moment. An equivalent mass imbalance can also be added to the main counterweight to maintain static balance. In a way, the scroll-type machine can be said to have three counterweights: one major counterweight to provide static balance, and two smaller counterweights, of identical imbalance, spaced 180 degrees apart and axially spaced apart to provide dynamic balance with one of the other. the minor weights located in the same location as the major weight. Thus, the primary weight may consist of the combination of the major weight and one of the minor weights, while the secondary weight is simply the other minor weight.

The offset between the center of the drive shaft and the center of said eccentric drive bearing defines an angular reference that rotationally orients the drive shaft. All moving masses within the machine may be defined by their axial position along the axis of the drive shaft and by their angular orientation with respect to the angular reference of the eccentric drive bearing. Likewise, the locations of the primary counterweight and the secondary counterweight are also defined by the axial positions along the axis of the drive shaft and their angular positions with respect to the angular reference of the eccentric drive bearing. The mass imbalances of these counterweights are chosen to counteract the mass imbalances of all moving masses.

In normal scroll machines, the drive means, primary counterweight, and secondary counterweight are all separate components located at separate axial locations along the drive shaft. Normally, the primary counterweight is interposed between the support bearing and the drive means and said secondary counterweight is located at the opposite end of the drive shaft. During manufacture, locating means must be provided to position these weights correctly, both axially and angularly, on the drive shaft. Said locating means may consist of locating elements between the counterweights and the drive shaft, may consist of external accessories or may consist of a combination of locating elements and accessories. This construction requires the fabrication, alignment, and assembly of a number of components during the manufacture of the spiral machine, all of which add to the cost of manufacture. In some designs, the drive shaft and main counterweight may be combined into a single component, but with the same general design.

The support bearing means typically includes two bearings which support the main drive shaft and which, in turn, are supported by a structure, frame or crankcase. In scroll-type machines in which a motor (for compressors or pumps) or a power transfer device (for example, a generator for expanders or hydraulic motors) is integrated, the motor or power transfer device is supported by the structure or frame and are located between the two bearings, or just outside the two bearings. The motor rotor component or power transfer device is attached to the drive shaft. The result of such tight integration is that the drive shaft, counterweights and structure or frame are largely specially designed for a single motor or power transfer device. This has the advantage of reducing material content when larger machinery is mass-produced, but is relatively inflexible or difficult to change if design variations of the motor or power transfer device are desired.

A requirement for proper operation of scroll type machines is that the two scrolls must be restrained with respect to any relative rotation between them. The orbital spiral follows a circular path or orbit with respect to the fixed spiral, but no relative rotation is allowed. In some designs, both scrolls are adapted to rotate together about offset axes (unlike the conventional fixed-orbit arrangement), but both rotate at the same speed and the angular phase between the two scrolls remains the same, meaning that they do not rotate relative to each other.

A number of different mechanisms can be used to prevent relative rotation between the two coils, but an Oldham coupling (comprising an Oldham ring and matching features on the two respective coils) is in common use today. A normal Oldham ring comprises a solid body, more or less in the shape of a ring. The body may be oblong or irregular in shape to accommodate other features of the machine, but will generally follow the pattern of a closed ring. Axial or radial projections of the body of the Oldham ring are provided with axially extending surfaces or keyways that engage corresponding surfaces of the respective coils to complete the coupling assembly and prevent relative rotation between the coils, while that authorize orbital action.

The ring-shaped part of Oldham's ring is normally flat and of more or less uniform thickness, being generally distributed around a radial plane at all points around the ring. A radial plane passing through the Oldham ring centroid will divide the Oldham ring into two continuous annular portions. Thus, the main body of the Oldham ring will have a space reserved specifically to contain it and allow free movement during operation. This dedicated space adds to the overall height (ie, axial length) of the scroll type machine and thus increases the size and weight of the scroll machine.

Therefore, one aspect of the present invention is directed at improving the state of the art in Oldham coupling design to avoid the need for a dedicated axial space for the coupling and thereby reduce the cost of coupling. overall size of the displacement machine.

In some applications where the working fluid (steam) must be isolated from the outside air (such as in a refrigeration loop), the compressor and drive motor are contained within a sealed casing that isolates the working fluid from the outside air. to the outside environment. The vapor flows around the compressor and engine and provides cooling, especially for the engine.

The drive motor, usually an electric motor, is usually integrated into the overall compressor assembly. The motor stator is integrated into the compressor frame and the motor rotor is mounted directly to the compressor shaft, which also incorporates the compressor drive means (e.g. eccentric bearing) and counterweights which may be placed on both sides of the motor or even attached directly to the rotor. This arrangement provides acceptable economy and simplicity by minimizing the number of separate components that make up the engine and compressor combination. However, a given compressor is dedicated to a particular size and design of motor. Physical changes to the motor often require extensive changes to the compressor frame and drive shaft to accommodate the new motor.

On larger compressors, the motor line is often standardized with common motor sizes and configurations found through a relatively limited selection of motor suppliers. It is rarely necessary to change to a different size motor and the compressor design can be relatively stable with respect to motor selection.

But for smaller compressors, there are a wide variety of motor types and manufacturers to choose from. These motors are typically available as pre-packaged modules, with the motor frame, shaft and bearings integrated into a single product for a wide range of applications, a small scroll compressor being just one.

Therefore, another aspect of the present invention is directed to an overall compressor design that allows the use of a range of prepackaged motors of various sizes with minimal or no changes to the compressor or motor.

Objects and summary of the invention

Accordingly, it is an object of the present invention to locate the high pressure port of a high side scroll type machine at the center of the orbital scroll, so that the high pressure fluid passes directly from the center of the orbital scroll. above the middle of the drive bearing. The low pressure or inlet port can then be located on a radially outer portion of the fixed scroll, which may have a solid base plate, thus avoiding any need to provide means for fluid communication between the fixed scroll and the casing. compressor (which is at high pressure).

It is a related object to greatly simplify the structure around the set of scrolls and, in some cases, to provide the option of having the fixed scroll itself form an outer end wall of the compressor casing.

In accordance with the invention, the high pressure fluid passes directly from the center of the orbital scroll over the drive bearing means coupled to the orbital scroll and thus through a direct path between the high pressure port pressure and inside the compressor casing. The lubricant entrained in the steam flow serves to lubricate the drive bearing means and other mechanical components of the moving machine. This arrangement is suitable for systems where the fluid flow is contained within a closed loop and a fixed amount of recirculated lubricant is present. However, this can be easily adapted to open-loop systems, where the fluid passes through the displacement machine once and is not recirculated, providing a means to inject lubricant into the inlet stream and optionally withdraw it from the outflow. exit.

As a result, the high-side scroll machine is simpler, more compact, and easier to manufacture than an equivalent high-side machine with the high-pressure port in the center of the stationary scroll.

In accordance with another aspect of the present invention, the scroll machine combines the eccentric drive bearing means, primary counterweight, and secondary counterweight in a single component or module. (referred to as an artifact in the description) that can be attached to the end of the drive shaft, adjacent to the orbital scroll. This module is designed as a single unitary part, suitable for casting, molding, forming or machining operations, so that the sizes and locations of the necessary counterweights, in relation to said eccentric drive bearing means, form an integral part of the assembly. part already formed and no subassembly, alignment operation, or alignment feature is required. Since all angular relationships are built into the drive module, there is no need for angular alignment between the drive module and the drive shaft. The module or fixture is preferably designed to be mounted at the end of a drive shaft, although the module could also be formed integrally with the drive shaft.

In accordance with another aspect of this invention, the drive module may be standardized, in terms of the interface with the motor or power transfer device, so that a wide variety of motors or power transfer devices can be easily adapted. to a particular model of spiral machine.

The drive shaft and shaft support bearing means may be packaged as part of the motor assembly or power transfer device. This allows easy access to a wide range of commercially produced motors or other drive devices, without the need for significant design changes to integrate several different devices into a scroll-type machine. Only the details of device attachment, alignment, and attachment of the drive module to the drive shaft need to be considered. The rated bearing life of such a device, when applied to the scroll machine, would simply be one of the product specifications along with other performance specifications.

Yet another aspect of the present invention is to improve the Oldham coupling for the spiral machine. In one embodiment of the present invention, the main body of the Oldham ring can be considered to be divided into four arc-shaped segments. A first pair of diametrically opposed segments bridges and slidingly engages the corresponding orbital spiral surfaces for Oldham coupling. The first pair of segments occupies approximately the same level, ie, the same axial position, as the base plate of the orbital spiral but does not extend beyond the floor surface of the orbital spiral. The space between the ends of the pair of segments is filled by existing Oldham key flanges on the orbital scroll. The first pair of segments occupies otherwise unused space on the machine. The second pair of diametrically opposed segments (oriented generally 90 degrees to the first pair) bridges and slidingly engages the corresponding surfaces of the fixed coil for the Oldham coupling. The second pair of segments occupies a level beginning around the floor of the base plate of the orbital spiral (also from the surface of the tip of the fixed spiral) and moving away from the floor of the orbital spiral but not extending along of the plane defined by the floor of the orbital spiral. This makes the coupling arrangement more compact. The Oldham ring symmetry of this design eliminates any polarity or laterality, making it impossible to install incorrectly.

The ends of the pairs of segments may favorably extend so as to overlap over a reasonable distance in a common radial or lateral plane. With the pairs of segments fused together at the overlapping areas, the Oldham ring becomes a single solid object that can be fabricated by a variety of methods.

It is not necessary to specifically provide any particular axial space to accommodate the Oldham ring. The space it occupies, with the first pair of segments extending between the key flanges of the orbital scroll and with the second pair of segments bridging over the key flanges, is a space that is already present in the compressor design and not nothing else is used. There is no need to provide clearance along a single axial plane, such as is required to accommodate the conventional flat ring of prior art Oldham couplings.

Yet another aspect of the present invention is to design the scroll machine to allow for the incorporation of a pre-packaged drive unit including stator, rotor, casing, bearings and shaft, as is common in commercially available motors. The drive unit can be attached to the compressor frame and a drive module can then be attached to the end of the motor shaft. The motor shaft and bearings serve as the main compressor shaft and bearings. The design changes, if any, that accompany a motor change are limited to the details of connecting the drive unit to the compressor frame and connecting the drive module to the motor shaft.

Other aspects, objects, and advantages of the invention are disclosed in the following detailed description, in the appended claims, and in the accompanying figures.

Brief description of the drawings

Figure 1 is an exploded isometric view of a scroll type machine, in this case a compressor according to one embodiment of the present invention, as viewed from the end of the scroll.

Figure 2 is an exploded isometric view of the same compressor as viewed from the engine end.

Figure 3 represents a cross-sectional isometric view of the same compressor.

Figure 4 represents a cross-sectional orthographic view of the same compressor.

Figure 5 is an isometric view of a fixed scroll in accordance with the present invention.

Figure 6 is an orthographic plan view of the same fixed scroll.

Figure 7 is an isometric view of an orbital scroll as viewed from the front or side of the blade in accordance with the present invention.

Figure 8 is an isometric view of the orbital scroll as viewed from behind or away from the blade in accordance with the present invention.

Figure 9 is a cross-sectional side orthographic view of the same orbital spiral.

Figure 10 is an isometric view of an Oldham ring as used in the present invention.

Figure 11 is an isometric view of an Oldham ring divided into sections showing a dividing plane. Figure 12 is a cross-sectional side orthographic view of the drive housing.

Figure 13 is an orthographic representation of a motor as used in the present invention.

Figure 14 is an isometric view of the drive device used in the present invention.

Figure 15 is an orthographic plan view of the drive device.

Figure 16 is a cross-sectional side orthographic view of the drive device.

Figure 17 is a schematic representation of the drive system including the drive bearing and orbital scroll drive hub.

Figure 18 is a cross-sectional side orthographic view of the motor-compressor module.

Figure 19 is a cross-sectional isometric view of the compressor housing.

Detailed description of the one or more preferred embodiments

The spiral machine of an embodiment of the present invention is illustrated in the accompanying Drawing Figures, which illustrate the component parts thereof. Generally, the scroll compressor 10 of the present embodiment includes a motor-compressor module 11 with a drive gallery 12. Between the module 11 and a main compressor casing 80, a motor chamber 14 is defined. The pair of scrolls is shown in this case as a fixed scroll 20 and a corresponding orbital scroll 30, which fixed scroll has an inlet (low pressure) port 21 located in a radially outward portion and a fixed scroll helical blade 22 having a pointed surface 23. Fixed scroll 20 also has a flat face 24, a shoulder 25, a pilot floor 26 with an outside diameter 27, and a pilot diameter 28. In the center of the scroll blade there is a blind recess or mirror port 29, which is will explain later.

The orbital scroll 30, which has a defined orbital path 31 relative to the fixed scroll 20, has a scroll vane 32, several anti-thrust pads 33, a plurality of flat faces 34, a drive hub 35 on the side opposite the vane 32, the drive hub having an inside diameter 36 defining a point of contact 37 with the drive bearing, a center 38 of the drive hub, and a discharge port 39 penetrating the scroll 30 about the axis o hub.

A drive gear 40 for achieving orbital movement of the scroll 30 is comprised of a shaft bore 41, an eccentric journal 42 having a journal center 43, and a drive bearing 45 having a predetermined bearing outside diameter 46 drive. Shaft bore 41 has a shaft bore center 47 located on the main drive shaft of the compressor. To prevent oscillation or vibration caused by eccentric motion of the orbital scroll, the drive 40 also includes a primary counterweight 48 and a secondary counterweight 49.

Restraint of any rotation of the orbital scroll 30 with respect to the fixed scroll is achieved by an Oldham ring 50, which in this case appears to be composed of four arcuate segments, and whose shape defines slidingly engaging key surfaces 54 with the flat faces 24 and 34 of the fixed and orbital coils 20 and 30, the ring comprising a lateral dividing plane 56, a first pair of segments 57 and a second pair of segments 58.

A drive housing 60 is shown, housing the aforementioned components, with a rear flange surface 61, a flat surface 62 for engaging the motor, a pilot hole 63 and a flat face 66, for engaging the pilot ground 26 of the drive. fixed scroll, having an outside diameter 68. An outlet port 69 allows passage of compressed working fluid vapor.

The driving power for the orbital scroll is provided in this case by an electric motor 70, having a motor shaft 71 with a shaft center or axis 77, a flat surface 72 and a pilot diameter 73. A set of bolts is provided. 74 or similar fixings to hold the motor to the drive housing.

Compressor casing 80 is shown with a flat or flange 81, an O-ring 83 and annular O-ring groove 84, a retaining ring 85 and annular retaining ring groove 86, a hole 87, a power supply 88 and a discharge duct 89.

Referring first to Figures 1 through 4 of the drawings, scroll compressor 10 includes a fixed scroll 20 and a orbital scroll 30. The fixed scroll 20 and the orbital scroll 30 constitute a pair of conventional scrolls, each of which has a respective involute-shaped blade 22 and 32, which fit together to form pairs of sealed mobile gaps. They are crescent shaped. The coil type principle is well known in the art and can be used to transport, compress or expand various fluids and gases.

With further reference to Figures 5-9, the orbital scroll 30 is driven through a circular path by the drive gear 40 which includes an eccentric crankpin 42 and drive bearing 45 which together urge the orbital scroll 30 to contact the fixed scroll 20. The orbital scroll 30 and the fixed scroll 20 contact each other through the orbital scroll vane 32 and the fixed scroll vane 22. The driving device 40, which includes drive bearing 45 further forces orbital scroll 30 to move in a circular path that is defined by the geometry of orbital scroll vane 32 and fixed scroll vane 22. Orbital scroll 30 is constrained to move in a plane sideways, without rotation, by means of the Oldham ring 50. Four of the eight key surfaces 54 of the Oldham ring 50 slidingly engage the fixed scroll 20, through a set of four faces flats 24, and the other four key surfaces 54 of the Oldham ring 50 slidingly engage orbital scroll 30 through a set of four flats 34.

Within the art, the Oldham ring is typically keyed between the scrolls as in the present invention or between the orbital scroll and a fixed structure within the compressor, such as a crankcase or bearing housing (for example, the drive housing). 60). Keying to a fixed frame requires the additional step of angularly aligning the fixed scroll with the frame to provide the proper angular orientation between the orbital scroll and the fixed scroll. Keying to a fixed frame offers the option of allowing the Oldham ring to fit behind the orbital spiral, i.e. between the orbital spiral and the frame, which may offer advantages in diametral (smaller) ring size , further facilitating a smaller diameter of the compressor in general. However, keying to a fixed structure requires adding to the structure (eg, drive housing 60) precision machined surfaces to engage the Oldham ring and precision alignment features on both the structure and the fixed spiral, to facilitate the spiral alignment operation, either self-aligning or accessory-aligned. The keying between the two spirals provides direct and integrated angular alignment, without the need for accessories or additional alignment operations. The spirals become self-aligning. The keying between the coils also tends to concentrate the various precision features in the two coil parts and allows for simpler and less precise (and therefore less expensive) fabrication of components other than the coils.

In conventional prior art scroll machines, with the Oldham ring keyed between the scrolls, the ring body is typically a solid ring of generally constant thickness uniformly distributed about a lateral plane. Posts, extending axially from the body of the ring, fit into keyways or flats on the two coil components. The ring body may be located between the two spirals with posts extending from both sides of the Oldham ring body, or the body may be located below the orbital spiral with posts extending from one side of the ring body. Oldham ring and with some features directly keyed to the adjacent orbital spiral and some features extending beyond the orbital spiral to keyed to the fixed spiral. In both cases, a specific axial space must be reserved for the ring body, all at the same level.

Referring to Figures 10 and 11, in the present invention, although the Oldham ring 50 is a single solid component, it is conceptually composed of four segments positioned at two different axial locations. A pair of segments 57 extends between the four flat surfaces 34 or 24 of the orbital coil 30 or the fixed coil 20, respectively, and a pair of segments 58 extends between the four flat surfaces 24 or 34 of the other coil, i.e. that is, the fixed spiral 20 or the orbital spiral 30, respectively. The pairs of segments 57 and 58 are joined at their ends in a single plane of symmetry 56. As a general rule, the parts of the pair of segments 57 do not cross the plane to the side occupied by the pair of segments 58, and likewise , the portions of the pair of segments 58 do not cross the plane to the side occupied by the pair of segments 57. As a result, the Oldham ring 50 does not require a dedicated axial space to be reserved for it. Rather, each pair of segments extends only between its respective set of flat surfaces 24 or 34 and occupies otherwise unused axial space within the compressor. If desired, pairs of segments 57 and 58 can be further retracted from plane 56 with axially extending segments joining pairs of segments 57 and 58 at the four pairs of segment ends.

The Oldham ring 50 has been designed to be fully symmetrical in the sense that the ring pair 57 is identical to the ring pair 58 and the Oldham ring 50 can be installed on the compressor in any of four possible orientations, i.e. , it is not possible to mount it incorrectly. It may be desirable, in some cases, to allow the ring to be non-symmetrical along plane 56, such as to have a different spacing between flats 24 of fixed scroll 20 and flats 34 of orbital scroll 30. The pair of segments 57 or the pair of segments 58 may also be non-symmetrical, in the sense that the pair of segments 57 may comprise two segments of different shapes or the pair of segments 58 may comprise two segments of different shapes. But whether the ring is designed symmetrically or non-symmetrically, there will still be two segments operating on one side of a 56 side plane and two segments operating on the other side of the 56 plane.

Referring to Figure 12 in addition to Figures 1-4, drive housing 60 is nested within fixed scroll 20. Flat face 66 engages pilot ground 26 of fixed scroll to establish axial position and perpendicularity. between drive housing 60 and fixed scroll 20. Outside diameter 68 mates with pilot diameter 28 of the fixed scroll to establish centerline concentricity between drive housing 60 and fixed scroll 20. In this example, components are self-aligning by this fit between features 66 and 26 and between features 68 and 28. Alternatively, some or all of this alignment between fixed scroll 20 and drive housing 60 may be provided by external fixtures for some or all alignment attributes, means being provided for maintaining alignment after fixtures have been removed.

Referring further to Figure 13, motor 70 is attached to drive housing 60 and motor shaft 71 penetrates the drive housing on the scroll side. In this example, motor 70 is secured to drive housing 60 by three bolts 74, although other means of attachment may be used. Motor 70 is axially and perpendicularly aligned with drive housing 60 through flat surface 72 which engages flat surface 62 of drive housing 60. Motor 70 is concentrically aligned with drive housing 60 through the pilot bore 73, which mates with pilot hole 63 in drive housing 60. Alternatively, some or all of the alignment between motor 70 and drive housing 60 may be provided through external fittings, means being provided to maintain alignment. alignment after removing accessories. In the present invention, motor 60 is an electric motor, but it is understood that motor 60 could be a hydraulic motor, air motor, or any other prime mover that provides rotational output.

Referring now to Figures 14-16, drive 40 is connected to motor shaft 71. In this example, drive 40 presses on shaft 71 through an interference fit between shaft bore 41 and shaft 71, but it is understood that any of a wide variety of attachment methods may be used, including combining drive 40 and shaft 71 into a single component. Drive 40 is aligned concentrically and perpendicularly with shaft 71 through the press fit on shaft 71. The axial position of drive 40 relative to motor 70 can be determined by physical features located in the shaft bore. 41 and on or adjacent to motor shaft 71, or by external fittings during manufacturing or assembly.

Drive bearing 45 is mounted on eccentric crankpin 42. In this example, drive bearing 45 is a ball bearing pressed on crankpin 42; however, other types of bearings may be used, including a solid disc with a smooth bore bearing directly against eccentric journal 42. Drive bearing 45 is aligned with drive gear 40 by the fit between drive bearing 45 and the crankpin 42 and by axial locating features, such as a mechanical stop, or by external fittings.

The axial loads, the axial, perpendicular, and concentric alignment chain between fixed scroll 20, drive housing 60, motor 70, and drive fixture 40, including drive bearing 45, all combine to determine position of drive bearing 45 relative to fixed scroll 20 in the compressor assembly. Orbital scroll 30 is interposed between fixed scroll 20 and drive bearing 45. Orbital scroll 30 is not rigidly constrained to be in any particular position or orientation relative to any other component of the compressor. The orbital scroll 30 is free to move laterally or radially, within the limits of the geometry of the fixed and orbital scroll vanes 22 and 32, and also within the limits of the radial clearance between the drive bearing 45 and the diameter inside of drive hub 36. Orbital scroll 30 is free to move axially within the clearance permitted by the gap defined between tip surface 23 of fixed scroll and flat face 66 of drive casing 60. In this way , when the compressor is not in operation, the orbital scroll 30 can be said to be "loose" within the assembly, with no particular position or orientation being imposed on it.

In the assembly, drive bearing 45 is located within inner diameter 36 of the orbital scroll drive hub and, when driven by motor 70 through drive gear 40, the outer diameter of drive bearing 46 acts against the inner diameter of drive hub 36, at contact point 37, to push orbital scroll blade 32 against fixed scroll blade 22, in the lateral or radial plane, and to follow a circular orbit path defined by the resulting contact between the fixed scroll vane 22 and the orbital scroll vane 32.

Figure 17 shows a schematic representation of drive bearing 45, with outside diameter 46 and drive bearing center 43, located within drive hub 35 having inside diameter 36 and center 38. The drive shaft center 77 coincides with the center of fixed scroll 20 and defines the center of rotation of drive 40. During normal operation, when orbital scroll vane 32 is in contact with fixed scroll vane 22 and the outside diameter of drive bearing 46 is pushing against drive hub bore 36, the orbital scroll is forced by pressure and inertial loads to move in a circular orbital path 31 that is centered on fixed scroll 20 and is defined by the respective geometries of fixed scroll blade 22 and orbital scroll blade 32. In Figure 17, the motor 71 and thus also the drive 40 rotate clockwise and the drive bearing center 43 also moves clockwise in a circular path centered on the center of tree 77.

The outside diameter of drive bearing 46 contacts the inside diameter of drive hub 36 at point of contact 37 and the instantaneous direction of motion of orbital scroll 30 is clockwise, as indicated in Figure 17, although the center of drive bearing 43 moves down and to the right as also indicated in Figure 17. Assuming that there is no slip between the outer diameter of drive bearing 46 and the inner diameter of drive hub 36 at the point of contact 37, the difference in velocity vectors between orbital scroll center 38 and drive bearing center 43 results in a rolling action between drive bearing 40 and drive hub bore 36. As As a result of the rolling action, the outer diameter of drive bearing 46 will rotate counterclockwise, as shown in Fig. Figure 17, although the drive system rotates clockwise. The total rotational speed of drive bearing 45 relative to crankpin 42 will be the sum of the rotation induced by this reverse rolling action plus the rotational speed of motor shaft 71. Therefore, it is necessary to design the bearing for drive 45 to operate at a slightly higher rotational speed than motor shaft 71.

The contact force Fc between the outer diameter of drive bearing 46 and the inner diameter of drive hub 36 is applied at the point of contact 37 and is directed perpendicular to the two surfaces 46 and 36 at the point of contact. This contact force Fc will have a component Ft acting in the instantaneous direction of motion of orbital scroll 30. This force balances a gas compression force generated within the pair of scrolls that opposes the action of drive bearing 45 and represents the force against which compression work is done.

In this example, the drive bearing center 43 is positioned so that the line of action of the contact force Fc acts at an angle a with respect to the instantaneous direction of motion of the orbital scroll. In this way, in addition to generating a tangential force component Ft in the direction of motion of the orbital scroll to perform compressive work, the contact force Fc also generates a radial force component Fr that acts to push the orbital scroll 30 radially outward to increase the load between orbital scroll vane 32 and stationary scroll vane 22. This may be done to counteract a radially inwardly acting gas force, generated by the set of scrolls, which tends to separate the blades 32 and 22 of the fixed and orbital scrolls. On larger compressors, where the centrifugal inertial action of a larger and heavier orbital scroll is sufficient to counteract the radial force of the gas, the drive bearing center 43 can be repositioned to reduce or eliminate the torque component. radial force Fr, acting outward, from the contact force Fc, or even to reverse the radial force component Fr to act radially inward against the centrifugal inertial action of the orbital scroll 30 and thus reduce the load between the blades 32 and 22 of the fixed and orbital spirals.

The advantage of this drive system, rather than simply rigidly mounting drive bearing 45 to drive hub 35, where orbital scroll 30 is driven in a fixed circular path centered on motor shaft 71, rather than the path defined by the scroll blades 22 and 32, is within its tolerance for deviations of the actual orbital path 31 from the ideal circle centered on the motor shaft 71. Normal manufacturing tolerances, both dimensional and alignment, give as a result, an orbital path generated by the blades deviates significantly from the ideal orbital path centered on the shaft. In the drive arrangement of Figure 17, the orbital scroll 30 can move radially in and out in response to orbital path deviations generated by the vanes. The orbital scroll vane 32 and the fixed scroll vane 22 can thus remain in continuous sealing contact. As the orbital spiral 30 moves radially inward and outward, the orbital spiral center 38 in Figure moves downward or upward, respectively, and the contact point 37 moves in the direction of increasing or decreasing. the contact angle a, also respectively.

If the orbital scroll 30 were constrained to rigidly follow a circular path centered on the center of shaft 77, it would be necessary to reduce the radius of the orbital path 31 to avoid mechanical interference between the scroll blades 32 and 22 as a result of clearance tolerances. manufacturing and assembly alignment. The radially adaptive drive system defined by drive gear 40 and drive hub 35, as illustrated in Figure 17, allows the scroll blades to remain in sealing contact despite the necessary deflections imposed by variations in pressure. manufacturing. It also allows for transient deviations from the ideal orbital path in the presence of contaminants or liquid in the scroll assembly that would otherwise lead to hydraulic jamming or interference.

In addition to providing the function of the eccentric crankpin 42 and drive bearing 45, the drive 40 also provides two counterweights, the primary counterweight 48 and the secondary counterweight 49. The size, location, and orientation of the two counterweights 48 and 49 are selected and calibrated so that the entire rotodynamic system defined by drive 40, including drive bearing 45, orbital scroll 30, and Oldham ring 50, is in both static and dynamic equilibrium. In machine designs conventional spiral, the three functions of the drive system, i.e. the mechanical drive, the primary counterweight and the secondary counterweight, are normally performed by separate components distributed in separate locations along a drive shaft that also includes a integrated engine.

The present invention decouples the mechanical drive function of motor 70 and allows either the drive system (drive device 40 and orbital scroll drive hub 35) or motor 70 to be modified with little or no impact on the other. Additionally, the specific geometric relationships between the eccentric crankpin 42 and the two counterweights 48 and 49 are "locked" into a single component rather than requiring assembly and alignment of several components in several operations. Any prime mover, whether electric, hydraulic, pneumatic or otherwise, need only meet the requirements of shaft power, shaft radial load and mechanical interface to be applied to this compressor. No significant redesign or retrofitting is needed to change from one engine type or design to another.

The combined assembly of stationary scroll 20, orbital scroll 30, drive gear 40 (including drive bearing 45), Oldham ring 50, drive housing 60, and motor 70 together form an integrated motor-compressor module 11. that can be packaged and applied in a number of different ways. Illustrated in Figure 18 is the motor compressor module 11. In the present invention, the motor compressor module 11 is mounted within a semi-hermetic compressor housing 80. In addition to appearing in Figures 1-4, the compressor housing 80 is illustrated in detail in Figure 19. The rear flange surface 61 of the drive housing 60 seats against the flat surface 81 of the compressor housing 80 which establishes the axial position of motor-compressor module 11 within compressor casing 80. The outside diameter of fixed scroll 27 matches the compressor casing bore 87 enough for a snug fit, establishing the radial position (concentricity) of the fixed scroll 20 and thus the concentricity of motor-compressor module 11 within compressor casing 80. A sealing element 83 fits within sealing groove 84 in the side wall of bore 87 and seals against the outside diameter of Fixed scroll 27. A beveled retaining ring 85 fits within the retaining ring groove 86 of compressor casing 80 and seats against the ridge of fixed scroll 25. The action of r The retaining ring spring 85 loads and holds the drive module 11 within the compressor housing 80. In this manner, the compressor motor module 11 is sealingly located and secured within the compressor housing 80. One or more electrical conduits 88 for conducting the motor power cables to the sealed space within the compressor casing 80, and a discharge conduit 89 is provided for compressed vapor to exit the compressor casing.

This design concept can be easily converted to a hermetic type compressor by removing the retaining ring 85 and joining the compressor casing 80 to the fixed scroll OD 27 with some type of vapor tight seal, such as welding, stamping, soldering, etc. brazing, soldering, rolling stamping, crimping, gluing, or other suitable joining process. Optionally, in addition to the joining process, an annular-type seal 83 may be used or a sealant applied to ensure gas-tightness of the joint. Proper watertight supply terminals and pipe connections would replace the corresponding threaded and gasketed components in this design example.

When motor 70 is energized, which rotates motor shaft 71 and drive 40, orbital scroll 30, as described above, is driven in a circular path while orbital scroll vane 32 is supported radially. against the fixed scroll vane 22. The orbital scroll 30 is prevented from any rotational movement by the action of the Oldham ring 50, located between the orbital scroll 30 and the fixed scroll 20. The scroll vanes interact in a conventional manner, steam is conveyed from inlet port 21, compressed within sealed crescent-shaped chambers, and discharged into drive housing 60 through discharge port 39. Fixed scroll 20 also has a blind recess 29 of "mirror port" that helps the discharge flow process.

The high pressure discharge port 39 through the floor of the orbital scroll directs all discharge flow to the drive bearing system, which is unusual, if not unique, in current scroll practice. The normal arrangement has the discharge flow through the fixed scroll 20 (with an open through port instead of the mirror port blind recess 29) reserving the space behind the orbital scroll 30 for the bearing, drive and lubrication systems that they are intentionally kept separate from the direct flow through the compressor.

In a conventional closed-loop refrigeration or air conditioning circuit, a percentage of the compressor lubricant circulates throughout the system at any given time. This is largely due to the inherent difficulty of completely separating the lubricant from the coolant flow. Conventional compressor designs capture as much return lubricant as possible and return it to an internal sump to replenish lubricant lost in the discharge flow of the compression mechanism. When applied to a closed-loop system, the present invention directs all return lubricant directly to the compression chambers and discharges the entire combined flow of refrigerant and lubricant into drive gallery 12, which is the space defined by the combination of fixed scroll 20, drive casing 60, and motor 70. Drive gallery 12 contains, or is adjacent to, all critical moving parts of the compressor, including drive gear 40 with drive bearing 45, the Oldham ring 50, the tip-to-ground sliding interface between the fixed scroll 20 and the orbital scroll 30, and the motor shaft bearings.

Designs of so-called high-side compressors, both scroll and non-scroll, in which all of the return flow passes through the compression mechanism and is discharged into the mechanical drive space which operates through the compression mechanism are well known in the art. ambient discharge pressure. However, conventional designs direct the flow through a discharge port located in the stationary scroll and along a separate path from direct exposure to the mechanical drive and lubricant sump. These provide means to separate the flow of lubricant from the flow of compressed vapor and return the lubricant to a controlled and isolated sump, from which a lubricant pumping system supplies lubricant to the bearings and scroll drive. Conventional (i.e., commercially produced) low-side compressor designs are very similar in that the flow of lubricant is separated and returned to the sump, where pumping and distributing means deliver the lubricant to the bearing system and drive. The most significant difference is the ambient suction pressure in the mechanical drive space and that the lubricant separation process takes place upstream, ie before the compression device instead of after.

Mist-lubricated compressors, including scroll and other types, are also well known in the art. They are most commonly applied in automotive air conditioning applications or other small transportation air conditioning and refrigeration applications. However, they are generally low side designs, with the discharge flow exiting the compressor from a fitting connected directly to a discharge port on the fixed scroll.

Any and all lubricants and vapors passing through compressor 10 will be discharged through port 39, through and around drive bearing 45, and into drive gallery 12. Compressed vapor exits gallery 12 through outlet port 69 along with any lubricant that is being entrained in the steam flow. In this embodiment, port 69 is located at the top of drive gallery 12, in an effort to allow gravity to pick up lubricant on the opposite side and bottom of drive gallery 12. Others may be added. means, such as screens or baffles within drive gallery 12, or around port 69, to further separate the flow of lubricant and tend to retain lubricant within drive gallery 12. In this way, the gallery Drive 12 tends to act as a lubricant sump, but that is not managed. There are no means for pumping or distributing the lubricant. Any supply of lubricant from the bottom of drive gallery 12 will be through the splashing action of moving parts and turbulent vortex flow driven by rotary drive 40. As long as lubricant returns from the system to compressor 10 through the suction flow, there is no need for a lubricant reserve in drive gallery 12. However, if there is more resident lubricant in drive gallery 12, that will allow a lower percentage of lubricant circulation per the system, which is generally desirable. This also provides a reserve of lubricant for critical moving parts in the event of a transient loss of lubricant return.

The discharge pressure acting on the orbital scroll 30 from the drive hub side serves to bias it against the fixed scroll 20, in opposition to the axial force generated by internal pressure which tends to separate the scrolls. In this manner, the coils are pressure loaded against each other to make effective sealing contact between the tip and ground surfaces.

During the compressor start-up phase, the discharge and suction sides are at the same pressure, so there is no force to push the scrolls against each other. However, at start-up a pressure appears almost immediately, generated internally by the compressive action within the scroll set, which pushes the orbital scroll 30 and tends to separate it from the fixed scroll 20. During this start-up phase, the anti-thrust pads 33 , adjacent the flats 34 of the orbital scroll 30, bear against the flat face 62 of the drive housing 60. This necessarily results in an axial clearance between the orbital scroll 30 and the stationary scroll 20 which allows leakage between the volumes. adjacent compression. This leakage results in degraded performance and flow through the compressor 10. However, if the axial clearance is controlled within reasonable limits, the compressor 10 will generate enough flow to create a back pressure opposite the system restriction or load, until enough pressure is developed to overcome the axial gas separation force and to axially load the orbital scroll 30 against the stationary scroll 20. In this way, the compressor "primes" itself after a start with balanced pressure.

After exiting drive gallery 12 through port 69, the compressed steam flows into engine chamber 14, where the steam absorbs the heat produced by the engine, i.e. the engine is cooled by the flow of steam. . After flowing around the engine, the vapor exits the compressor through discharge conduit 89. In the present invention, discharge conduit 89 is positioned at the bottom of engine chamber 14 to prevent the creation of "traps" or pockets where lubricant could accumulate outside of the main steam flow. Any lubricant entrained in the discharge vapor flow will be entrained by the flow and force of gravity to the discharge line 89 and will flow back into the system to be returned to the compressor once again.

Claims (8)

1. A scroll type displacement machine, adapted to move a working fluid between a low pressure environment and a high pressure environment, the scroll type displacement machine comprising: a casing (80); a pair of scrolls comprising an orbital scroll (30) and a fixed scroll (20), said fixed and orbital scrolls having respective scroll vanes (22, 32) that fit together; an Oldham ring means (50) coupled to said fixed and orbital scrolls (20, 30) to prevent rotation of said orbital scroll (30) but allowing said orbital scroll (30) to enjoy orbital motion about an axis of said fixed spiral (20); a rotary drive shaft (71) having an axis of rotation and adapted for rotary movement about said axis of rotation; bearing means (67) supporting said rotary drive shaft (71) within said housing and allowing said rotary drive shaft to enjoy rotary motion within said housing; an eccentric drive bearing means (45) located on said drive shaft, adjacent said pair of scrolls, and operatively coupled to said orbital scroll (30) such that rotation of said drive shaft corresponds to orbital motion of said orbital spiral; said housing enclosing at least said eccentric drive bearing means (45), at least a portion of said pair of scrolls (20, 30) and at least a portion of said rotary shaft (71); said fixed scroll (20) having a low pressure port (21) located in a radially outer portion of the scroll blade (22) thereof and in communication with said low pressure environment; said orbital scroll (30) having a high pressure port (39) disposed in a radially central portion of the scroll blade (32) thereof; Y an internal path coupled to the high pressure port (39) resulting in said high pressure environment being located within said housing, and characterized by what the high pressure port (39) is located, in relation to said eccentric drive bearing means (45), in such a way that the high pressure fluid passes directly from the high pressure port, above said bearing means eccentric drive bearing means (45) and thence through a flow path to said interior of said casing (80), whereby fluid flow serves to first pass over the drive bearing means and at less than one adjacent surface (36) of said orbital spiral (30). The scroll-type displacement machine according to claim 1, wherein said working fluid includes entrained lubricant, and said internal path is adapted such that entrained lubricant to the high pressure environment within said casing provides lubrication. for at least said eccentric drive bearing means (45). The scroll type displacement machine according to claim 1, wherein said scroll type machine is configured as a compressor and said internal fluid path directs the flow of said working fluid in a direction from said low pressure environment towards said high pressure environment. 4. The scroll type displacement machine according to claim 3, further comprising a closed loop path for said working fluid wherein the working fluid exits through a pressure port (89) of said casing and returns to said low pressure port (21) of said fixed scroll, and wherein said working fluid is recirculated through said scroll machine. The scroll type displacement machine according to claim 1, wherein said eccentric drive bearing means (45) is formed as an eccentric drive module (40) also including a primary counterweight (48) fixed to the itself and a secondary counterweight (49) attached to said drive module (40) and spaced axially from said primary counterweight, whereby the primary counterweight and secondary counterweight are configured to provide static and dynamic rotational balance for said displacement machine spiral type; and wherein said primary weight (48) and said secondary weight (49) are located between said pair of scrolls (20, 30) and said bearing means (67). The scroll-type displacement machine according to claim 1, wherein said fixed scroll has a plurality of flat surfaces (54) in first planes that are parallel to an orbital axis of the orbital scroll (30), and the orbital spiral has a plurality of flat surfaces arranged in second planes parallel to said orbital axis and perpendicular to said first planes, and said Oldham ring half (50) is divided by a lateral plane (56) into four segments (57 , 58) generally arc-shaped, two (57) of said four segments including a pair of surfaces (54) adapted to slidingly engage flat surfaces (24) of said fixed scroll (20), and including two ( 58) of said four segments include a pair of surfaces (54) adapted to slidingly engage flat surfaces (34) of said orbital scroll (30), to allow orbital motion between the fixed and orbital scroll. such but to block the relative rotational movement between them. The scroll-type displacement machine of claim 6, wherein said generally arc-shaped segments (57, 58) overlap in said lateral plane (56), each with an adjacent one of said arc-shaped segments. arc, creating four pairs of overlap zones. The scroll type displacement machine according to claim 1, comprising a drive casing (60) having a surface (66) for engaging a surface (26) of the fixed scroll (20), a surface (62) on which is mounted a drive motor (70), said drive motor being coupled to said rotary drive shaft (41), said rotary drive shaft (71) passing through a conduit (67) of said drive casing (60) to said eccentric drive bearing means (45).