METHODS OF FORMING MODULATED CAPACITY SCROLLS

Methods of forming modulated capacity scroll compressors are provided, where at least two distinct mold shapes are formed of foam material and then joined together to form a mold assembly. The mold assembly defines one or more substantially horizontal features, such as a horizontally oriented fluid passage or a weight-reduction recess in a solid wall. In certain aspects, the mold assembly defines a junction between a portion of a horizontal fluid passage and a portion of a vertical fluid passage. A molten metal displaces the foam material of the mold assembly to solidify and form the scroll component.

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Description
CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/040,416, filed on Mar. 28, 2008. The entire disclosure of the above application is incorporated herein by reference.

FIELD

The present disclosure relates to compressors, and more particularly to a lost foam method for forming the components of a modulated capacity compressor.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Scroll-type compressors are used in a wide variety of industrial and residential applications, often to provide a desired heating or cooling effect. A scroll compressor typically has two involute scroll forms which are intermeshed together to define sealed pockets. The scroll itself follows a path of motion that allows the involute portion of the scrolls to capture and transfer sealed pockets from the outer portion of the involute (or the inlet) to the central portion of the involute (or outlet). These fluid pockets are reduced in size and compressed as they are transferred from inlet to outlet. Once the pocket reaches the central portion of the involute (the outlet), the fluid pocket will be at its smallest volume and highest pressure and thus can be discharged to a delivery system.

One manner of increasing the operating efficiency of these types of machines includes providing capacity modulation. Often capacity modulating scroll compressor designs include fluid passages into a compression region. For example, certain capacity modulating scroll compressors have a fluid injection port in a lateral region of a non-orbiting scroll of the scroll assembly. In certain compressor designs, the fluid injection port is a horizontal passage in fluid communication with a generally vertical fluid passage. In other compressor designs, capacity modulating scroll compressors may bypass gas from the fluid pockets to the inlet pressure of the compressor and also may include a horizontal passage in fluid communication with a substantially vertical fluid passage. In other compressor designs, capacity modulating scroll compressors may bypass gas from the fluid pockets to the chamber in the housing of the compressor at inlet pressure and also may include a horizontal passage in fluid communication with a generally vertical fluid passage.

Typical methods for manufacturing the non-orbiting scroll, such as billet machining, casting and forging, may require additional processing steps to form horizontal port features in the scroll component, such as the fluid injection port. Further, these manufacturing methods may require horizontal features to be finished after formation via post-machining, which introduces additional processing steps during manufacturing. Streamlining manufacturing processes for scroll components to form high quality scroll components is desirable.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

In various aspects, the present disclosure provides methods of manufacturing scroll components having a fluid passage. In certain aspects, the methods include forming a plurality of distinctly shaped molds with a foam material. A mold assembly is formed defining a scroll component shape by adhering the plurality of molds together, where the scroll component shape includes a body portion having a substantially vertical feature and a substantially horizontal feature. At least a portion of the substantially horizontal feature intersects with at least a portion of the substantially vertical feature to form the fluid passage. The method also includes molding the scroll component by displacing the foam material of the mold assembly with molten metal that solidifies to form the scroll component.

In other aspects, a method is provided for manufacturing a modulated capacity scroll component that includes forming a mold assembly defining a capacity modulating scroll component shape by adhering a first foam mold having a first shape to a second foam mold having a second distinct shape. The scroll component shape includes a body portion having at least one capacity modulating feature formed therein having a shape defined by a combining a first portion of the first foam mold and a second portion of the second foam mold, where the first and second portions are adhered together with an adhesive. The method also includes molding the scroll component by displacing the first and second foam molds with molten metal, which solidifies to form the modulated capacity scroll component.

In yet other aspects, methods of manufacturing a modulated capacity fixed scroll component are provided by the present disclosure. In certain aspects, such a method includes forming a mold assembly defining a scroll component shape by adhering a plurality of distinctly shaped expendable foam molds together via an adhesive. The scroll component shape comprises a body portion having a capacity modulating feature defining a first opening in a base plate of the scroll component shape connected to a substantially vertical fluid passage and a second opening in a solid wall of the body portion connected to a substantially horizontal fluid passage opening, where a portion of the substantially vertical passage intersects with a portion of the substantially horizontal passage to provide fluid communication between the first opening to the second opening. The modulated capacity fixed scroll component is formed by molding and displacing the mold assembly with molten metal that solidifies to form the modulated capacity fixed scroll component.

The present disclosure also provides a method of manufacturing a scroll component including forming a mold assembly defining a scroll component shape by disposing a core comprising a material that dissolves and/or disintegrates in water in a mold pattern and filling the mold pattern with a plurality of beads comprising an expendable material. The plurality of beads is exposed to a fusing treatment to fuse the beads to one another. Then the mold assembly is substantially surrounded with a refractory material. The scroll component is molded by displacing the expendable material of the mold assembly with a molten metal that solidifies to form the scroll component. Lastly, the core is removed from the solidified scroll component by exposing the core to an aqueous solution.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

FIG. 1 is a sectional view of a scroll compressor having fluid injection capacity modulation formed in accordance with the methods of the present disclosure;

FIG. 2 is a fragmentary sectional view of an exemplary non-orbiting scroll component having capacity modulation figures including a plurality of molds forming a mold assembly;

FIG. 3 is a perspective view of the non-orbiting scroll component of the compressor of FIG. 2 including lateral weight reduction recess pockets;

FIG. 4 is a partial sectional view of a non-orbiting scroll component depicting an L-shaped junction between a first horizontal feature and a second vertical feature forming a capacity modulation passage;

FIG. 5 is a sectional view of a scroll compressor having a capacity bypass system formed in accordance with certain methods of the present disclosure;

FIG. 6 is a sectional view of the non-orbiting scroll component capacity bypass features of the compressor of FIG. 5;

FIG. 7 is a plan view of the capacity bypass features of FIG. 6 showing the compressor having a first capacity;

FIG. 8 is a plan view of the of the capacity bypass features of FIG. 6 showing the compressor having a second capacity;

FIG. 9 is a plan view of the capacity bypass features of FIG. 6 showing the compressor having a third capacity;

FIG. 10 is a perspective view of the non-orbiting scroll and capacity bypass system of the compressor of FIG. 5; and

FIG. 11 is a sectional view of a foam scroll component in a refractory material prior to casting in accordance with the methods of the present disclosure.

 DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

In various aspects, the present teachings pertain to methods of manufacturing scroll components that have a compression mechanism and at least one fluid passage. Often such fluid passages are associated with a scroll compressor having a capacity modulating design. One example of a capacity modulating scroll compressor design includes a fluid injection system that increases operating efficiency and capacity. So called “fluid” injection encompasses liquid and/or vapor injection systems.

In certain aspects, the methods provided herein relate to the use of enhanced formation processes for forming scroll components, particularly those scroll components having at least one capacity modulation feature, such as a fluid passage, fluid port, or fluid opening. A capacity modulation feature generally includes a fluid passage, which can include a substantially horizontal passage or feature, a substantially vertical passage or feature, and/or a bleed hole or port feature formed within at least a portion of a scroll compressor component. In certain aspects, the scroll component includes a capacity modulation feature, including a first feature and a second distinct feature formed therein, such as a first substantially horizontal or a second substantially vertical orientation within the scroll compressor. By “substantially horizontal” it is generally meant that the feature has a general horizontal orientation (although it may deviate from horizontal at different angles or have non-linear configurations and shapes) within the scroll component body, so that it forms a passage extending through an outer surface or region of a scroll compressor body forming an opening or passage therein, such as a wall or solid body portion. Similarly a “substantially vertical” feature has a general vertical orientation (although it may deviate from vertical by different angles or have non-linear configurations or shapes), which generally forms a passage having an opening in a terminal surface of the scroll component (e.g., a top or bottom surface). Certain scroll components often include internal junctions between substantially horizontally oriented features and one or more substantially vertical features. However, such junctions potentially require complex processing and/or machining and pose particular difficulty during manufacture of scroll components. In accordance with the present teachings, methods of forming such junctions are improved by use of molds formed of expendable materials, such as foam-based materials, which are used in a lost-foam method of processing to cast a scroll component from a molten metal that solidifies to form a scroll component that has high dimensional accuracy. Furthermore, the present casting methods enable the formation of intricate and/or complex features in a scroll component design, including junctions between portions of substantially vertical features and substantially horizontal features, which are formed within the body portion of the scroll component.

Thus, in certain aspects, the methods include forming a mold assembly from a plurality of distinctly shaped molds made from an expendable foam material, where the plurality of distinctly shaped molds is joined together to form a mold assembly defining a scroll component shape. The scroll component is molded by displacing the mold assembly (made of expendable foam material) with a molten metal, generally by volatilizing the expendable material, which dissipates as it is replaced by the metal. After the expendable material is displaced with molten metal, the metal solidifies to form the scroll component having a shape corresponding to the original scroll component shape of the mold assembly. Such a process is referred to as a so-called “lost-foam casting,” which will be discussed in more detail below.

FIG. 1 shows an exemplary hermetic scroll compressor 10 of the so-called “low-side type,” where the motor and compressor are cooled by suction gas in the hermetic shell. While FIG. 1 depicts a hermetic scroll compressor of the low-side type, the present teachings are also applicable to other scroll and rotary compressors, such as hermetic machines, open-drive machines and non-hermetic machines. Compressor 10 may include a cylindrical hermetic shell 11 housing a compression mechanism 12, a main bearing housing 13 and a motor assembly 14. A refrigerant discharge fitting 15 is optionally attached to an upper end of shell 11. A suction gas inlet fitting 16 may be attached to shell 11 at opening 17. Compression mechanism 12 may be driven by motor assembly 14 and supported by main bearing housing 13. Main bearing housing 13 may be affixed to shell 11 at a plurality of points in any desirable manner.

Compression mechanism 12 may include an orbiting scroll 18 and a non-orbiting scroll 19. Orbiting scroll 18 may include an end plate 20 having a spiral vane or wrap 21 on an upper surface thereof and an annular flat thrust surface 22 on a lower surface. In certain aspects, a cylindrical hub 23 projects downwardly from thrust surface 22, which may be drivingly engaged with motor assembly 14 through various means known in the art.

With reference to FIG. 1, non-orbiting scroll 19 may include an end plate 24 having a non-orbiting spiral wrap 25 on a lower surface thereof. Non-orbiting spiral wrap 25 may be interleaved with wrap 21 of orbiting scroll 18, thereby creating an inlet pocket 26, intermediate pockets 27, and an outlet pocket 28. Non-orbiting scroll 19 may have a centrally disposed discharge passageway 29 in communication with outlet pocket 28 and an upwardly open recess 30 which may be in fluid communication with discharge fitting 15.

An annular recess 31 may be located in an upper surface of non-orbiting scroll 19 and may contain an annular floating seal 33 for isolation from the presence of gas under suction and discharge pressure. Annular recesses 31 are optionally in fluid communication with a source of intermediate fluid pressure by means of upper portion of vertical fluid passages 34. One or more portions of vertical fluid passages 34 can optionally blocked by a plug 32 (e.g., a brass plug) to prevent direct fluid communication from the source of pressurized fluid in certain regions, as necessary. A lower portion 35 of vertical fluid passage 34 provides fluid communication between at least one of the intermediate pockets 27 and the source of intermediate pressure. Where no plug 32 is present, the vertical fluid passage 34 is a single continuous passage (rather than being dissected into upper and lower regions, for example, as shown on the right side of FIG. 1). Non-orbiting scroll 19 may therefore be axially biased against orbiting scroll 18 by the forces created from the discharge pressure acting on the central portion of non-orbiting scroll 19 and those created by intermediate fluid pressure acting on the bottom of annular recess 31. A fluid injection system 36 may be in fluid communication with compression mechanism 12 by means of horizontal fluid injection ports 37. Fluid injection system 36 is described in commonly owned U.S. Pat. No. 5,755,271, which is hereby incorporated by reference in its entirety.

In FIG. 2, a mold assembly 82 is shown with cast metal prior to any post-casting finishing, such as machining or drilling. In FIG. 2, substantially horizontal features, such as horizontal fluid ports 60, may be located in non-orbiting scroll end plate 50 extending through a sidewall 62 of body portion 61, progressing generally radially into non-orbiting scroll 50, and ending at a substantially vertical portion. The intersection of horizontal fluid ports 60 and vertical fluid passages 56 provides for fluid communication therebetween and after finishing, between bypass system and an intermediate compression pocket, such as 44. The intersection of horizontal fluid ports 60 and fluid passages 56 may form any variety of shapes, for example, in certain aspects a T-shaped intersection or junction may be formed like in FIG. 2. FIG. 4 depicts a post-machined finished casting, with an L-shaped intersection optionally formed between the horizontal fluid port 60′ and the vertical fluid passage 56′. The intersection or junction of a terminal portion of such horizontal features with a vertical feature can pose difficulties during various formation processes. For example, certain regions of the intersection may be blind or difficult to reach with tools to achieve the desired dimensions. In certain aspects, various features may be added after casting. For example, additional fluid passages can be drilled after the horizontal fluid port 60′ and vertical fluid passage 56′ are cast. A counter-sink portion 64 may be drilled into the sidewall 62 after casting. A lower connection passage 86 can be drilled after casting to connect the vertical fluid passage 56′ to one or more compression pockets 87. One or more plugs 90 may be placed in the junction of the horizontal fluid port 60′ and vertical fluid passage 56′ after casting to prevent fluid communication with annular recess 52, where desired.

A plurality of fluid inlet passages (e.g., fluid injection ports) and/or bleed holes may be provided in the scroll component. In FIGS. 2 through 4, fluid inlet passages (e.g., fluid injection ports) 60 or 60′ optionally have the counter-sink portion 64 (FIG. 4) in sidewall 62 at a location intermediate the upper surface 59 of non-orbiting scroll end plate and an upper surface 68 of an extension member 70 of a non-orbiting scroll 50. While non-orbiting scroll 19 of FIG. 1 depicts one fluid injection port 37, FIG. 2 depicts two horizontal fluid ports 60. The present teachings may encompass any number of fluid ports, as desired. Further, it should be appreciated that the horizontal features shown are exemplary and can vary from the number, configuration, and designs that are shown.

The present teachings further contemplate forming substantially horizontal features with lost-foam casting methods in scroll compressors having a capacity bypass modulating configuration as shown in FIGS. 5-10. Compressor 132 is an exemplary hermetic scroll refrigerant-compressor of the low-side type, as illustrated in the vertical section shown in FIG. 5. Compressor 132 may include a cylindrical hermetic shell 116 which houses a compression mechanism 118, a main bearing housing 120, a motor assembly 122, a refrigerant discharge fitting 124, and a suction gas inlet filling 126. Shell 116 may include an end cap 128 at the upper end thereof and a transversely extending partition 129. The refrigerant discharge fitting 124 may be attached to shell 116 at opening 130 in end cap 128. The suction gas inlet fitting 126 may be attached to shell 116 at opening 133. The compression mechanism 118 may be driven by motor assembly 122 and supported by main bearing housing 120. The main bearing housing 120 may be affixed to shell 116 at a plurality of points in any desirable manner.

The motor assembly 122 may generally include a motor 134, including a drive shaft 138. The motor 134 may include a motor stator 140 and a rotor 142. The motor stator 140 may be press fit into a frame, which may in turn be press fit into shell 116. Drive shaft 138 may be rotatably driven by rotor 142. Windings 144 may pass through motor stator 140. Rotor 142 may be press fit on drive shaft 138. Drive shaft 138 may include an eccentric crank pin 148 rotatably journaled in a main bearing housing 120. The lower interior portion of shell 116 may be filled with lubricating oil.

Compression mechanism 118 may generally include an orbiting scroll 164 and a non-orbiting scroll 166. Orbiting scroll 164 may include an end plate 168 having a spiral vane or wrap 170 on the upper surface thereof and an annular flat thrust surface 172 on the lower surface. Thrust surface 172 may interface with an annular flat thrust bearing surface 174 on an upper surface of thrust plate 121. A cylindrical hub 176 may project downwardly from thrust surface 172 to receive the drive shaft 138.

Non-orbiting scroll 166 may include an end plate 182 having a spiral wrap 184 on lower surface 186 thereof. Spiral wrap 184 may form a meshing engagement with wrap 170 of orbiting scroll 164, thereby creating an inlet pocket 188, intermediate fluid pockets 190, 192, 194, 196, and outlet pocket 198. Non-orbiting scroll 166 may have a centrally disposed discharge passageway 200 in communication with outlet pocket 198 and upwardly open recess 202 which may be in fluid communication with a discharge muffler 201 via an opening 203 in partition 129. Discharge muffler 201 may be in communication with discharge fitting 124 and may be defined by end cap 128 and partition 129.

Non-orbiting scroll 166 may include an annular recess 204 in the upper surface thereof having parallel coaxial side walls in which an annular floating seal 205 is sealingly disposed for relative axial movement. The bottom of recess 204 may be isolated from the presence of gas under suction and discharge pressure by floating seal 205 so that it can be placed in fluid communication with a source of intermediate fluid pressure by means of a fluid passage (not shown). A passage 206 includes a substantially horizontally oriented portion 207 that is connected to a substantially vertically oriented portion 208, which form an “L-shaped junction.” The horizontally oriented portion 207 is connected to a sidewall opening 209 formed in an external surface of the sidewall 226. The substantially vertically oriented portion 208 of passage 206 connects to at least one base plate opening 211 formed in the lower surface 186 of end plate 182. A plurality of such openings 211 may extend into an intermediate fluid pocket 190, 192, 194, 196. Non-orbiting scroll 166 may therefore be axially biased against orbiting scroll 164 by the forces created by discharge pressure acting on the central portion of non-orbiting scroll 166 and those created by intermediate fluid pressure acting on the bottom of recess 204. Various additional techniques for supporting non-orbiting scroll 166 for limited axial movement may also be incorporated in compressor 132.

Relative rotation of the scroll members 164, 166 may be prevented by an Oldham coupling, which may generally include a ring 212 having a first pair of keys 214 (one of which is shown) slidably disposed in diametrically opposed slots 216 (one of which is shown) in non-orbiting scroll 166 and a second pair of keys (not shown) slidably disposed in diametrically opposed slots in orbiting scroll 164.

With additional reference to FIGS. 7-9, non-orbiting scroll 166 may include first, second, third, and fourth passages 218, 220, 222, 224 extending through an exterior sidewall 226 thereof and into intermediate fluid pockets 190, 192, 194, 196. First, second, third and fourth passages 218, 220, 222, 224 may each include a seal 225 disposed in an outlet thereof. One or both of third and fourth passages 222, 224 may have a greater radially inward extent than both first and second passages 218, 220. With additional reference to FIG. 10, a capacity modulation or bypass system 228 may be coupled to non-orbiting scroll 166.

Capacity bypass system 228 may include a modulation ring 230 and an actuation mechanism 232. Seals 225 may be engaged with modulation ring 230. Modulation ring 230 may include a generally annular body rotatably disposed around exterior sidewall 226 of non-orbiting scroll member 166. Modulation ring 230 may include first and second portions 234, 236 each having a first flow path 238, 239 and a second flow path 240, 241 extending therethrough for selectively venting one or more of intermediate fluid pockets 190, 192, 194, 196, as discussed below. A pin 242 may extend from modulation ring 230 for engagement with actuation mechanism 232.

Actuation mechanism 232 may be in the form of a solenoid having an extendable and retractable arm 244. A biasing member (not shown), such as a coil spring, may normally urge arm 244 into an extended position. Arm 244 may include a recess 248 in an end 250 thereof. Pin 242 may extend into recess 248 for actuation of modulation ring 230, as discussed below.

Actuation mechanism 232 may rotate modulation ring 230 between three positions, seen in FIGS. 7-9. In the first position (shown in FIG. 7) compressor 132 operates at a maximum capacity. At the maximum capacity, first and second portions 234, 236 of modulation ring 230 seal passages 218, 220, 222, 224 in non-orbiting scroll 166. More specifically, in the first position, first flow paths 238, 239 are not in communication with first and second passages 218, 220, and second flow paths 240, 241 are not in communication with third and fourth passages 222, 224. Capacity may be modulated by retraction of arm 244 and therefore rotation of modulation ring 230 in a clockwise direction to a second position (shown in FIG. 8) and by extension of arm 244 and therefore rotation of modulation ring 230 in a counter-clockwise direction to a third position (shown in FIG. 9).

The second capacity is less than the first capacity. When in the second capacity, arm 244 may be in an innermost position and modulation ring 230 may have first flow paths 238, 239 aligned with first and second passages 218, 220 in non-orbiting scroll 166. Capacity may additionally be modulated to a third capacity (seen in FIG. 9), where modulation ring 230 is rotated to the third position. The third capacity is less than the second capacity. When in the third capacity, arm 244 may be extended to an outermost position to rotate modulation ring 230 in a counter-clockwise direction from the second position to the third position. The third position may provide alignment between first flow paths 238, 239 and third and forth passages 222, 224 in non-orbiting scroll 166 and second flow paths 240, 241 and first and second passages 218, 220 in non-orbiting scroll 166.

As discussed above, the first capacity is greater than the second capacity and the third capacity is less than the second capacity due to the greater radially inward extent of third and fourth passages 222, 224 in non-orbiting scroll 166. The radially inward extent of first, second, third, and fourth passages 218, 220, 222, 224 may effectively reduce the wrap length of non-orbiting scroll 166. For example, non-orbiting scroll 166 may have a wrap angle of approximately 1330 degrees. First and second passages 218, 220 may extend into non-orbiting scroll member to a wrap angle of approximately 1000 degrees from a base circle of the involute. As such, in the second capacity where first and second passages 218, 220 are in communication with first flow paths 238, 239, the wrap angle of non-orbiting scroll 166 is effectively reduced to 1000 degrees. Third and fourth passages 222, 224 may extend into non-orbiting scroll 166 to a wrap angle of approximately 660 degrees from the base circle of the involute. As such, in the third capacity where first and second passages 218, 220 are in communication with second flow paths 240, 241 and third and fourth passages 222, 224 are in communication with first flow paths 238, 239, the wrap angle of non-orbiting scroll 166 is effectively reduced to 660 degrees.

Scroll pocket volume may be generally proportional to wrap angle. Therefore, according to the example above, the first capacity may generally be thirty-three percent greater than the second capacity and the third capacity may generally be thirty-three percent less than the second capacity. However, the first capacity may generally be ten to thirty-five percent greater than the second capacity and the third capacity may generally be ten to thirty-five percent less than the second capacity. Modulation ring 230 may be held in a constant position to provide the three capacities described above. Alternatively, modulation ring 230 may be cycled rapidly in order to provide an intermediate capacity.

Compressor 132 may be sized such that the second capacity corresponds to the system rated capacity of compressor 132 when incorporated into a heat pump system operated in a cooling mode. Compressor 132 may be operated in the first and second capacities when a heat pump system is operated in a heating mode. The first capacity may provide additional capacity for operation in a heating mode.

Compressor 132 may be operated in the second and third capacities when a heat pump system is operated in a cooling mode. More specifically, the third capacity may provide for more efficient operation of heat pump system in the light load cooling mode. Thus, capacity modulation of a compressor formed in accordance with the present disclosure may improve a heat pump system's heating seasonal performance factor (HSPF) and/or Seasonal Energy Efficiency Ratio (SEER). In various aspects, the present teachings provide improved methods of making such modulated capacity compressors having at least one substantially horizontal feature associated with the capacity bypass features, by using a lost-foam method of casting, where a mold assembly comprises a plurality of distinctly shaped molds.

With renewed reference to FIG. 3, the non-orbiting scroll 50 may further include additional features, such as recesses that reduce the weight of the scroll compressor, shown as weight-reduction pockets 66 extending into a portion of the bulk of the body of sidewall 62 from an outer surface 63 extending towards a major center axial axis (designated “A” in FIG. 3) of non-orbiting scroll 50. Weight reduction features, such as pockets 66, may be of any size and shape, but in various aspects, do not detrimentally impact the structural integrity or robustness of the sidewall 62 and hence, of the scroll component.

In certain aspects, the weight reduction pockets 66 are disposed in an intermediate region 65 of the sidewall 62 disposed between an upper end 67 and a lower end 69 of sidewall 62. In certain aspects, the intermediate region 65 is at least about 10 mm from the upper end 67 and at least about 10 mm from the lower end 69 to ensure structural integrity of the sidewall 62 of non-orbiting scroll 50; however, other dimensions are contemplated depending on the size of the scroll component and the properties of the specific metals used. Non-orbiting scroll 50 is depicted as having eight weight reduction pockets 66 disposed on an outer surface 63 of the sidewall 62; however, the present teachings may encompass an alternate number and configuration of features that provide weight reduction. Furthermore, as shown, the lateral recess weight reduction pockets 66 have a substantially rectangular shape, however, other shapes, such as substantially oval shapes are also contemplated in alternate aspects. In one example, the scroll component includes a plurality of weight reduction recesses, for example, at least four lateral recesses disposed at substantially the same circumferential distance from one another on the sidewall 62.

In various conventional manufacturing processes, substantially horizontal features, such as a fluid passage, can be formed in a multiple-step process to form a scroll component structure, for example by casting with a molten metal. During the casting process, a substantially horizontal feature is roughly defined by the mold cavity shape. After pouring the molten metal over the mold cavity, any residual casting materials (e.g., burn-on) on the surface are removed leaving a rough shape of the substantially horizontal feature in the as-cast surface, which is generally subsequently machined to a predetermined dimension to achieve the desired size and shape of the final substantially horizontal feature. However, casting material removal and finishing processes that form substantially horizontal features often contribute to complexity of machinery, operations, and durations during processing. Furthermore, the intersection of portions of substantially vertical and substantially horizontal features often presents particular difficulties in various formation processes, requiring additional finishing due to increased complexity. Additionally, machining such junctions may potentially create structural weaknesses in the scroll component, which is avoided when such junctions in scroll compressor components are formed in accordance with the present teachings.

Thus, in certain aspects, the present disclosure provides an improved method of manufacturing a scroll component having a fluid passage. The method includes forming a plurality of distinctly shaped molds with an expendable material, such as a foam material. By “distinct” shapes it is meant that the geometry of each respective shape is different in at least in one aspect, either by orientation when assembled and adhered together (e.g., non-super imposable mirror images) or by physical differences in shape, geometry, and/or features. A mold assembly defines a scroll component shape and is formed by adhering the plurality of molds together to define a scroll component shape. The scroll component shape comprises a body portion having a substantially vertical feature and a substantially horizontal feature. A portion of the substantially horizontal feature intersects with at least a portion of the substantially vertical feature to form the fluid passage. Then, the scroll component is molded by displacing the foam material of the mold assembly with molten metal that solidifies to form the scroll component.

In other aspects, a method is provided for manufacturing a scroll component. The method includes forming a mold assembly defining a scroll component shape by adhering a first foam mold having a first shape to a second foam mold having a second distinct shape. The scroll component shape includes a body portion having at least one substantially horizontal feature disposed therein. The substantially horizontal feature is optionally a fluid passage and/or a weight-reduction recess.

In certain aspects, the mold assembly thus defines a scroll component shape and may include a body portion having at least one substantially vertical fluid passage and at least one substantially horizontal fluid passage disposed in the body portion. Further, a portion of the substantially vertical fluid passage intersects with a portion of the substantially horizontal fluid passage. Thus, in certain aspects, the present disclosure provides a method of manufacturing a modulated capacity fixed scroll component having a fluid injection ports.

In yet other aspects, the mold assembly defines a scroll component shape that includes a body portion having at least one substantially vertical passage and at least one substantially horizontal feature disposed in the body portion. The substantially horizontal feature is a horizontal capacity bypass passage. A first opening in an end plate of the scroll component shape is connected to the substantially vertical passage, generally such an opening is formed in a compression pocket, as described previously. A second opening in the body portion, for example, through a solid wall of the body portion, is connected to the horizontal capacity bypass passage, thus permitting fluid communication between the first opening and the second opening through the vertical passage and the horizontal capacity bypass passage.

In addition, the body portion of the scroll component shape optionally further includes a solid wall having an outer surface with at least one weight-reduction recess disposed therein, according to the present teachings. The scroll component is molded by displacing the mold assembly with molten metal that solidifies to form the solid metal scroll component. In certain aspects, the metal comprises a ferrous metal or ferrous metal alloy, such as a gray iron metal composition. In other aspects, the metal comprises aluminum or aluminum alloys.

In certain aspects, the substantially horizontal feature, which is optionally a fluid passage and/or a weight-reduction recess, has a shape defined by combining a first portion of the first mold and a second portion of the second mold. For example, as shown in FIG. 2, a first upper mold 100 has a distinct shape from a second lower mold 102. A first portion 104 of the first upper mold 100 forms an upper portion of a first substantially horizontal fluid passage 106. A second portion 108 of the second mold 102 forms the lower portion of the first substantially horizontal fluid passage 106. The first and second portions 100, 102 are adhered together along respective contact surfaces to form a seam 110 with a suitable adhesive, such as a hot-melt adhesive, a glue stick, and the like. The mold assembly defines a finalized foam mold assembly 82 of the non-orbiting scroll 19 as divided through the center plane (e.g., 110) of horizontal fluid ports 60. Suitable hot-melt adhesives include those having a material selected from the group consisting of polypropylene, polyethylene, butadiene, isoprene (2-methyl-1,3-butadiene), 1,3-butadiene, chloroprene (2-chloro-1,3-butadiene), and isobutylene (methyl propene), ethylene-vinyl acetate, polymers, copolymers, equivalents and mixtures thereof. Often, adhesives include other conventional materials, such as stabilizers, tackifiers, viscosity modifiers, temperature performance modifiers, and fillers. By “hot-melt” it is generally meant that the adhesive softens at about 70° C. to about 90° C. and melts at about 100° C. to about 125° C.

A process for manufacturing a component (hereinafter described as exemplary non-orbiting scroll 19) according to the present disclosure includes providing a mold pattern tool to form at least two distinct foam mold shapes corresponding to an upper mold portion (such as 100) and a lower mold portion (such as 102), which are joined to form a mold assembly 82.

When forming upper and lower molds, the pattern mold tool is filled with an expendable material, such as polystyrene, polymethyl methacrylate (PMMA), expanded polystyrene, expanded methyl methacrylate, polyalkylene carbonate, copolymers and mixtures thereof. Such materials may be treated with a blowing agent, such as pentane, to lower the density. In various aspects, the distinctly shaped molds are formed by filling a pattern in the pattern mold tool with a plurality of beads comprising a material selected from the group consisting of as polystyrene, polymethyl methacrylate (PMMA), expanded polystyrene, expanded methylmethacrylate, polyalkylene carbonate, copolymers and mixtures thereof. In certain aspects, the material for forming the mold comprises polystyrene and/or expanded polystyrene.

The mold pattern filled with beads of foam material is exposed to a fusing treatment, such as steam treatment, which generally causes the beads to expand and fuse together in a thermal reaction. Such processes are described in Expandable Pattern Casting, by Raymond W. Monroe (1992), Ch. 5, which is herein incorporated by reference in its entirety. After a sufficient exposure time to the fusing treatment, the foam is fused forming cohesive foam mold shapes corresponding to the scroll component shape, such as non-orbiting scroll.

Next, upper and lower molds are joined along a major contact surface using an adhesive, such as a hot-melt adhesive, to form a foam mold assembly that defines the shape of the scroll component. In certain aspects, the amount of adhesive used to join upper and lower molds optimizes adherence, while minimizing vapors volatilized later in the lost-foam manufacturing process. The foam mold assembly is then joined with appropriate sprues, runners, gates and risers. Foam mold assembly may also be joined with other foam scroll components, thereby creating a tree of parts to be molded coincidentally.

In yet other aspects, after forming the mold assembly, surfaces of the mold assembly are substantially coated with a slurry material. Thus, foam mold assembly (for example, 82 of FIG. 2) may then be coated with a slurry material that includes a refractory or ceramic material, optionally dispersed in conventional carriers, such as water and other suitable solvents known to those of skill in the art. The slurry coating can minimize the foam mold assembly 82 from potentially reacting with other refractory materials and may also allow foam molds to retain their respective shapes when elevated temperatures are present in the manufacturing process. Notably, such a refractory coating also promotes coating of all interior and exterior surfaces of a mold assembly, so that the surfaces are substantially similar, thereby reducing any potential processing inconsistencies. The slurry-coated, foam mold assembly 82 may be dried to remove the solvent through any conventional methods known in the art and then placed in a container, such as a mold flask.

An exemplary lost-foam molding apparatus is shown in FIG. 11, where a container 92 having mold assembly 82 disposed in a refractory material 95. The mold assembly 82 is connected to at least one sprue and/or runner 96, through which the molten metal will be poured during casting.

Thus, the slurry-coated mold assembly 82 is disposed within a refractory material. A surface of foam mold assembly 82 is substantially surrounded with a refractory, such as low expansion foundry sand. Examples of suitable low expansion foundry sands include mullite sand, which is an aluminosilicate, olivine sand (e.g., green sand), silica sand, and mixtures thereof. While not limiting, certain low expansion foundry sands are better suited for use with specific alloys, for example mullite and olivine sands with ferrous-based metals and silica sand with aluminum-based metals. Container 92 is vibrated while the foundry sand refractory material 95 is added, thereby compacting the sand refractory material 95 and allowing it to flow into passageways in foam mold assembly 82, such as weight reduction pockets and fluid injection ports. The vibratory action of container 92 allows the sand refractory material 95 to naturally compact to a final shape. The vibratory action of the container 92 may also create an exothermic reaction which may cause foam mold assembly 82 to begin to dissipate. Thus, in certain processes, a hardened, slurry coating assists with shape retention of the foam mold assembly 82 during such heating and from the vibratory action used during processing.

Next, a molten metal is introduced to the sprue runner 96 and mold assembly 82. The molten metal may be selected from ferrous-based metal materials and aluminum-based metal materials known in the art, but in certain aspects, is a gray iron material. The molten metal displaces the foam and in certain aspects, slurry material. The remaining foam is completely dissipated into the foundry sand leaving only the ferrous material corresponding to non-orbiting scroll. Non-orbiting scroll component is allowed to cool, solidify, and then is removed from the container 92.

In an alternate method of the disclosure, a scroll component shape is defined by having an easily removed core material combined with one or more foam mold shapes. Conventional core materials typically contain a refractory or ceramic material, such as an aggregate and a curing binder systems. Core materials can be made via no-bake, cold-box, or hot-box curing systems for solidification. Hot-box treatment includes pre-heating (e.g., from temperatures ranging from about 40° C. to about 250° C.) the core material mixture with a thermosetting binder for curing. Cold-box treatment curing is typically achieved by a vapor or gas catalyst passed through the core material mixture. The cold-box curing is optionally conducted at slightly elevated temperatures (e.g., from about 35° C. to about 100° C.) to ensure vaporization of the catalyst. The core material is shaped by putting it into a pre-form pattern and allowing it to cure until it is capable of being handled. A no-bake system cures without any baking at ambient temperatures. A curing catalyst is added directly to the casting material mixture and placed in a shaped mold, where it subsequently solidifies.

Conventional core materials typically contain an aggregate, such as a bank or synthetic sand foundry sand. Bank sands are naturally occurring and may contain clay or other contaminants. Synthetic sands are formed with a base sand grain, which may be silica. Sand selection in a casting material is dependent on the application, such as grain size, physical properties, and how the sand reacts with the binder and specific metals being cast.

Thus, core materials contain a binder which can be no-bake, cold-box, or hot-box, as previously discussed. A phenolic urethane binder is suitable for both the no-bake and cold-box processes. In a no-bake curing system, a different solvent is used which reacts with a liquid curing catalyst mixed with the casting material mixture (including an aggregate and binder system) to form a mold mix. The liquid catalyst is mixed into the casting material mixture before shaping and cures within a matter of hours. In a cold-box process, a gaseous tertiary amine curing catalyst (such as TEA (tetraethylamine) and/or DMEA (dimethylethylamine)) is passed through a shaped core material mixture containing a phenolic urethane binder (typically consisting of a phenolic resin component and a polyisocyanate component). Phenolic urethane binders are well known for use in forming cores used in casting iron and aluminum.

Hot-box fabrication processes use resins that harden the sand when the core material is pre-heated (for example, to temperatures of about 35° to about 300° C.) and optionally the core pattern is heated to induce resin setting. Such hot-box resins may include binders based upon furan resins and furfuryl alcohols. Such resins are optionally cured in the presence of a latent acid curing catalyst. Ceramic mold mediums are another example of hot-box treated mold, where inorganic clay components are the binder and are cured with heat.

In certain aspects of the present disclosure, a core material is soluble in a common solvent, such as an aqueous solution containing water. Thus, the core material includes a mixture including a foundry sand, a binder, and a soluble additive, such as a water-soluble additive. The soluble additive facilitates and/or expedites removal of any residual core material from a scroll component formed using the core material, upon exposure to a solvent. Preferably, the soluble additive facilitates disintegration and/or dissolution of the core material, when the core is exposed to an aqueous water-based solvent system, and optionally, to heating, electrochemical and/or physical force. By “disintegration,” it is meant that the core material is broken down into smaller particulate form, in pieces small enough that the original solid form is readily removable from any substrate or hollow on or within the cast scroll part.

A soluble core is placed in position in a pattern mold tool and then subsequently filled with a foam material, such as the bead materials described previously. The beads and core are treated with steam causing the foam material to expand in a thermal reaction and fuse, as described above. The foam mold assembly 82′ fully encompasses the water core.

Foam scroll mold assembly 82′ is joined with appropriate sprues, runners, gates and risers. Foam scroll mold assembly 82′ may also be joined with other foam scroll mold assemblies 82′, thereby creating a tree of parts to be molded coincidentally. Foam scroll mold assembly 82′ may then be coated with a slurry material containing a refractory or a ceramic material and optionally dried, in accordance with the process discussed previously.

Foam scroll mold assembly 82′ is substantially coated with a low expansion foundry sand, such as mullite sand (an aluminum silicate) or silica sand, for example, by placing the foam scroll mold assembly 82′ into a container containing refractory/foundry sand, which is then vibrated and compacted.

A molten metal is poured into the sprues, runners, gates and risers within the container 92. Optionally, a ceramic cup can be employed as the down sprue instead of a sprue runner system. The molten metal displaces foam material in the foam scroll mold assembly 82′. The foam material forming the mold volatilizes as it contacts the molten metal and dissipates into the surrounding refractory material sand. Non-orbiting scroll 19 is allowed to cool and then removed from the container 92. The core remains within the solid scroll component, where it is then removed to form a horizontal fluid injection port.

Claims

1. A method of manufacturing a scroll component having a fluid passage, the method comprising:

forming a plurality of distinctly shaped molds with a foam material;
forming a mold assembly defining a scroll component shape by adhering said plurality of molds together, wherein said scroll component shape comprises a body portion comprising a substantially vertical feature and a substantially horizontal feature, wherein at least a portion of said substantially horizontal feature intersects with at least a portion of said substantially vertical feature to form the fluid passage; and
molding said scroll component by displacing said foam material of said mold assembly with molten metal that solidifies to form the scroll component.

2. The method of claim 1, wherein after said forming of said mold assembly, substantially coating said mold assembly with a slurry material; and

substantially surrounding said slurry-coated mold assembly with a refractory material comprising a material selected from the group: mullite sand, olivine sand, silica sand, and mixtures thereof.

3. The method of claim 1, wherein said adhering comprises applying an adhesive to at least one surface of said plurality of molds, wherein said adhesive comprises a material selected from the group consisting of polypropylene, polyethylene, isoprene, butadiene, isobutylene, ethylene-vinyl acetate, polymers, copolymers, and mixtures thereof.

4. The method of claim 1, wherein said forming of said plurality of distinctly shaped molds comprises filling a pattern with a plurality of beads and exposing said plurality of beads in said pattern to a fusing treatment to fuse said beads together, wherein said beads comprise a material selected from the group consisting of polystyrene, expanded polystyrene, polymethylmethacrylate, expanded methylmethacrylate, polyalkylene carbonate, copolymers and mixtures thereof.

5. The method of claim 1, wherein said substantially horizontal feature is a horizontal fluid injection port and said substantially vertical feature is a vertical fluid injection passage formed in the scroll component, said horizontal fluid injection port and said vertical fluid injection passage permitting fluid communication therebetween.

6. The method of claim 1, wherein said substantially horizontal feature is a horizontal capacity bypass passage, wherein a first opening in an end plate of the scroll component shape is connected to said substantially vertical passage and a second opening in said body portion is connected to said horizontal capacity bypass passage, thus permitting fluid communication between said first opening and said second opening through said substantially vertical passage and said horizontal capacity bypass passage.

7. The method of claim 1, wherein said portion of said substantially horizontal feature that intersects with said portion of said substantially vertical feature forms a T-shaped junction or L-shaped junction therebetween.

8. The method of claim 1, wherein said forming of said mold assembly further comprises positioning a core within the scroll component shape to define a portion of said substantially horizontal feature.

9. The method of claim 1, wherein said core is formed of a casting material capable of dissolving and/or disintegrating upon exposure to water.

10. A method of manufacturing a modulated capacity scroll component comprising:

forming a mold assembly defining a capacity modulating scroll component shape by adhering a first foam mold having a first shape to a second foam mold having a second distinct shape, wherein said scroll component shape comprises a body portion having at least one capacity modulating feature formed therein having a shape defined by a combining a first portion of said first foam mold and a second portion of said second foam mold, wherein said first and said second portions are adhered together with an adhesive; and
molding the scroll component by displacing said first and second foam molds with molten metal, which solidifies to form the modulated capacity scroll component.

11. The method of claim 10, wherein said scroll component shape has a major axial axis and said first portion of said first mold and said second portion of said second mold are adhered along respective surfaces to define a plane that is transverse to said major axial axis.

12. The method of claim 10, wherein said at least one capacity modulating feature comprises a substantially horizontal fluid passage and a substantially vertical fluid passage formed in the scroll component, wherein said substantially horizontal fluid passage and said substantially vertical fluid passage permit fluid communication therebetween.

13. The method of claim 12, wherein said portion of said substantially horizontal fluid passage that intersects with said portion of said substantially vertical fluid passage forms a T-shaped junction or L-shaped junction therebetween.

14. The method of claim 12, wherein said capacity modulating feature is a capacity bypass fluid passage comprising said substantially horizontal fluid passage and said substantially vertical fluid passage.

15. The method of claim 10, wherein after said forming of said mold assembly, substantially coating said mold assembly with a slurry material; and

substantially surrounding said slurry-coated mold assembly with a refractory material comprising a material selected from the group: mullite sand, olivine sand, silica sand, and mixtures thereof.

16. The method of claim 10, wherein said forming of said plurality of distinctly shaped molds comprises filling a first mold pattern defining an upper portion of the scroll component shape with a plurality of beads to form said first mold and filling a second mold pattern defining a lower portion of the scroll component shape to form said second mold, wherein said lower portion comprises an involute scroll form; and exposing said plurality of beads in each of said first and said second mold patterns to a stream treatment to fuse said beads together, wherein said plurality of beads comprise a material selected from the group consisting of polystyrene, expanded polystyrene, polymethylmethacrylate, expanded methylmethacrylate, polyalkylene carbonate, copolymers and mixtures thereof.

17. A method of manufacturing a modulated capacity fixed scroll component, the method comprising:

forming a mold assembly defining a scroll component shape by adhering a plurality of distinctly shaped expendable foam molds together via an adhesive, wherein said scroll component shape comprises a body portion comprising a capacity modulating feature defining a first opening in a base plate of said scroll component shape connected to a substantially vertical fluid passage and a second opening in a solid wall of said body portion connected to a substantially horizontal fluid passage opening, wherein a portion of said substantially vertical passage intersects with a portion of said substantially horizontal passage to provide fluid communication between said first opening to said second opening; and
molding the modulated capacity fixed scroll component by displacing said mold assembly with molten metal that solidifies to form the modulated capacity fixed scroll component.

18. A method of manufacturing a scroll component comprising:

forming a mold assembly defining a scroll component shape by disposing a core comprising a material that dissolves and/or disintegrates in water in a mold pattern and filling said mold pattern with a plurality of beads comprising an expendable material;
exposing said plurality of beads to fusing treatment to fuse the beads to one another;
substantially surrounding said mold assembly with a refractory material;
molding the scroll component by displacing said expendable material of said mold assembly with a molten metal that solidifies to form the scroll component; and
removing said core from the solidified scroll component by exposing said core to an aqueous solution.

19. The method of claim 18, further comprising machining the solidified scroll component to remove any remaining core materials after said removing.

Patent History
Publication number: 20090242160
Type: Application
Filed: Mar 27, 2009
Publication Date: Oct 1, 2009
Inventors: Richard A. Obara (Huber Heights, OH), Pride R. Bruner (Tipp City, OH)
Application Number: 12/413,118
Classifications
Current U.S. Class: Sequentially Forming Mold Portions On Same Shaping Member (164/24); Shaping A Forming Surface (e.g., Mold Making, Etc.) (164/6); Utilizing Particular Mold Materials (164/520)
International Classification: B22C 9/02 (20060101); B22D 23/00 (20060101); B22C 9/22 (20060101);