HK1189194A - Method and system for manufacturing a wheel - Google Patents

Abstract

A system for manufacturing a wheel includes a cope mold portion comprising internal cope mold walls and a drag mold portion comprising internal drag mold walls. The internal cope mold walls and internal drag mold walls define at least in part perimeter boundaries of a wheel cavity. The wheel cavity comprises a cavity center portion configured to form a wheel center portion of a wheel after solidification of a molten alloy in the cavity center portion, a cavity plate portion configured to form a wheel plate portion of the wheel after solidification of a molten alloy in the cavity plate portion, and a cavity flange portion configured to form a wheel flange portion of the wheel after solidification of a molten alloy in the cavity flange portion. The system includes a chill component positioned within the wheel cavity adjacent the cavity flange portion. The chill component is configured to provide directional solidification from the cavity flange portion toward the cavity plate portion of molten alloy in the wheel cavity.

Description

Method and system for manufacturing a wheel

RELATED APPLICATIONS

This application claims priority from united states provisional application No. 61/430738 entitled Method and System for manufacturing a Wheel, filed on 7/1/2011.

Technical Field

The present disclosure relates to wheels, and more particularly to methods and systems for manufacturing wheels, such as rail wheels.

Background

Conventional methods of manufacturing railway wheels have included graphite molds into which molten alloy is poured to cast the wheels. The sand backing in the graphite mold may act as an insulator to provide the desired setting. Inconsistencies may result if the sand backing moves in the mold. The use of graphite molds in the manufacturing process can also be very expensive.

Summary of The Invention

The teachings of the present disclosure relate to a system and method of manufacturing a wheel. According to one embodiment, a system for manufacturing a wheel includes: an upper die portion including an inner upper die wall and a lower die portion including an inner lower die wall. The inner cope mold wall and the inner drag mold wall at least partially define a perimeter boundary of a wheel cavity. The wheel cavity includes: a cavity center portion configured to form a wheel center portion of a wheel upon solidification of a molten alloy in the cavity center portion; a cavity plate portion configured to form a wheel plate portion of the wheel upon solidification of a molten alloy in the cavity plate portion; and a cavity flange portion configured to form a wheel flange portion of the wheel upon solidification of the molten alloy in the cavity flange portion. The system includes a cooling assembly positioned within the wheel cavity adjacent to the cavity flange portion. The cooling assembly is configured to provide directional solidification of molten alloy in the wheel cavity from the cavity flange portion toward the cavity plate portion.

In accordance with another embodiment, a method of manufacturing a wheel is provided, comprising: a cooling assembly is positioned within the wheel cavity. The wheel cavity includes a perimeter boundary at least partially defined by an inner upper mold wall of the upper mold portion and an inner lower mold wall of the lower mold portion. The wheel cavity includes: a cavity center portion configured to form a wheel center portion of a wheel upon solidification of a molten alloy in the cavity center portion; a cavity plate portion configured to form a wheel flange portion of the wheel upon solidification of molten alloy in the cavity flange portion; and a cavity flange portion configured to form a wheel flange portion of the wheel upon solidification of the molten alloy in the cavity flange portion. The cooling assembly is configured to provide directional solidification of molten alloy in the wheel cavity from the cavity flange portion toward the cavity plate portion. The method includes closing the cope and drag mold portions with a cooling assembly positioned in the wheel cavity and at least partially filling the wheel cavity with molten alloy. The molten alloy solidifies to form the wheel.

Technical advantages of particular embodiments may include the use of greensand molds that may reduce manufacturing costs. Another technical advantage of particular embodiments is the use of a cooling member around a flange portion of a mold cavity to provide a desired directional solidification of a molten alloy in the cavity. An additional technical advantage of particular embodiments is the use of a bowl, one or more filters, or a combination of both to remove inclusions from the molten alloy. The use of a bowl, one or more filters, or both may also reduce turbulence in the molten alloy as it enters the casting cavity. Another technical advantage of some embodiments is the use of risers adjacent to the cavity flange portion of the wheel cavity to reduce porosity in the wheel flange portion. In particular embodiments, a riser breaker core may be positioned adjacent to the riser to reduce the diameter of the riser at the attachment point to the casting wheel, which may facilitate removal of the riser.

Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages.

Brief Description of Drawings

A more complete understanding of certain embodiments will become apparent from the detailed description when considered in conjunction with the following drawings, wherein:

FIG. 1 is a cross-sectional view of a wheel manufacturing assembly according to certain embodiments;

FIG. 2 is a partial perspective view of components of a wheel manufacturing assembly according to certain embodiments;

FIG. 3 is another partial perspective view of components of a wheel manufacturing assembly according to certain embodiments;

FIG. 4 is another partial perspective view of components of a wheel manufacturing assembly according to certain embodiments;

FIG. 5 is another partial perspective view of components of a wheel manufacturing assembly according to certain embodiments; and

FIG. 6 is a perspective view of a filtration system of a wheel manufacturing assembly, according to certain embodiments.

Detailed Description

FIG. 1 is a cross-sectional view of a wheel manufacturing assembly according to certain embodiments. The manufacturing assembly 10 includes an upper die 20 and a lower die 24 into which molten alloy (such as liquid steel) is poured 20 and 24 to manufacture cast rail wheels. The upper and lower dies include a casting cavity 27 that is created when the dies are aligned and closed together. The inner walls of the casting cavity 27 may be formed using a pattern and a high pressure process to create the cavity in the mold. The walls at least partially define the surfaces of the cavity into which the molten alloy is poured and solidified for the manufacture of the wheel. In the illustrated embodiment, both the upper and lower dies 20, 24 include green sand 22, and the green sand 22 may include a combination of sand, water, and/or clay. The greensand 22 may be considered green in that it is not baked (e.g., no chemical bonding and not heated or treated) in some embodiments. Other embodiments may use other suitable materials, such as other types of sand, to make up the cope and drag molds. The casting cavity formed in the upper and lower dies 20, 24 includes a plate portion 62 for forming a plate section of the wheel, a flange portion 64 for forming a flange section of the wheel, and a center portion 65 for forming a center section of the wheel.

The manufacturing assembly 10 also includes a sprue 30, a core 32, a riser sleeve 36, a gate segment 34, an upper cooling member 40, and a lower cooling member 44. The sprue 30 contains molten alloy for a rail wheel. In particular embodiments, the sprue 30 is supported by the upper and lower dies and may not be supported by the core 32. In particular embodiments, core 32 includes resin bonded sand. The core 32 is used to form a central circular cavity in the wheel as the molten alloy solidifies around the core. Riser sleeve 36 insulates riser portion 37 formed by solidification of the liquid alloy after it has flowed down through the lower upper and lower die cavities. The gate segment 34 is configured into the lower die 24 using a mold and contains the liquid alloy as it flows down the sprue 30 and into the casting cavity 27 created by the upper and lower dies 20, 24. In a particular embodiment, the gate section 34 may include four in-gates, each separated by about 90 degrees, through which the liquid metal or alloy may flow into the casting cavity 27. The illustrated embodiment uses a top gating system that allows molten alloy to enter at the top of the assembly 10 to facilitate directional solidification from the bottom to the top of the casting cavity. Other embodiments may use other types of gating systems.

The upper and lower cooling members 40, 44 are generally circular and surround the flange portions 64 of the upper and lower mold cavities. In particular embodiments, the cooling element may comprise one or two halves, one half in the upper die and the other half in the lower die. The two halves may be joined by a pin and bushing (or other suitable assembly) and placed as one piece into the lower mold. The cooling element may be made of steel, graphite or other suitable metal or material. The cooling elements assist in providing the desired directional solidification by helping to ensure that the liquid alloy solidifies from outside the cavity (e.g., the flange portion) toward the inside (e.g., toward the plate portion). If the plate portion of the wheel were to solidify before the flange portion, the hot spot would be isolated in the flange portion of the wheel and could create unwanted holes in the casting. Some conventional methods of manufacturing railway wheels use graphite upper and lower molds with sand backings to act as insulators because the graphite molds act as cooling elements. However, this approach may provide inconsistent casting. The use of greensand and metal or graphite cooling only at the flange portions of the cavity increases the likelihood of consistent casting. Furthermore, the fact that the casting cavity is created from a green sand model (as opposed to using a backing placed into the cavity) reduces inconsistencies because the cavity will be maintained and another component that may create inconsistencies is not handled. In particular embodiments, the cooling member used may be fixed in the mold and reusable to cast multiple wheels in the same mold.

When manufacturing the wheel, molten alloy flows downwardly through the sprue 30 and into the casting cavity 27 after flowing through the in-gates of the gating system 34, as depicted by arrows 80 in FIG. 1. The alloy flows out to the flange portion 64 of the casting cavity and back up through the riser sleeve 36. Due to the upper and lower cooling members 40, 44, the molten alloy is first solidified in the flange portion, and then solidified in the outer to inner direction. The casting may be processed during the manufacturing process to complete the manufacture of the wheel. For example, in certain embodiments, the metal riser portion 37 remaining after the solid metal is removed from the mold may be removed by machining.

FIG. 2 is a partial perspective view of components of a wheel manufacturing assembly according to certain embodiments. The wheel manufacturing assembly 100 of fig. 2 is similar to the wheel manufacturing assembly 10 of fig. 1. The wheel manufacturing assembly 100 includes a sprue 110 inserted into a core 120. In some embodiments, the sprue 110 is supported by an upper or lower die, and in other embodiments, the sprue 110 may contact and/or be supported by mold tiles of the inner wall of the inner cylindrical cavity of the core 120. In this embodiment, the riser sleeve 124 insulates the core 120 from the molten alloy after the molten alloy flows through the casting cavity. Another riser sleeve 134 contains riser metal 130, which riser metal 130 can be removed by machining after casting in certain embodiments. The assembly 100 also includes an in-gate 140, which in-gate 140 may be one (e.g., four in some embodiments) of a plurality of gates created in the lower mold through which the molten alloy flows into the casting cavity. The cooling member is shown in an upper half 150 and a lower half 154. Solidification of the molten alloy forms the wheel casting 160. Line 156 shows the dividing line formed between the upper and lower dies.

FIG. 3 is another partial perspective view of components of a wheel manufacturing assembly according to certain embodiments. The manufacturing assembly 200 of fig. 3 is similar to the respective manufacturing assemblies 10 and 100 of fig. 1 and 2, but further includes an additional sleeve 220 to insulate the plate portion of the wheel casting to help ensure that the plate portion solidifies before the inner portion of the casting (but after the outer flange portion).

FIG. 4 is another partial perspective view of components of a wheel manufacturing assembly according to certain embodiments. The manufacturing assembly 300 of fig. 4 is similar to the respective manufacturing assemblies 10, 100, and 200 of fig. 1, 2, and 3, but further includes a bowl 310 and a filter 320. The bowl 310 is configured in the lower die and contains the molten alloy as it flows down the sprue 330 (as depicted by arrow 350) and into the casting cavity 340 created by the upper and lower dies.

The bowl 310 includes an in-gate 360 through which molten alloy enters the casting cavity. In particular embodiments, the crock 310 is constructed from one or more ceramic tiles. The bowl 310 helps prevent corrosion of the lower mold and assists in providing the desired laminar flow of molten alloy as it enters the casting cavity. In embodiments without a bowl, the pressure and velocity of the molten alloy as it enters the sprue and proceeds toward the casting cavity may cause increased turbulence and increased inclusions in the alloy.

The filter 320 helps to reduce inclusions and reduce turbulence carried by the molten alloy as it enters the casting cavity. The filter 320 is designed to withstand the temperature of the molten alloy. In some embodiments, the bowl 310 houses a filter positioned directly in line with the sprue 330. In a particular embodiment, the filter is housed directly adjacent to each gate including the in-gate 360. In some embodiments, the bowl houses a filter aligned with the sprue 330 and a filter adjacent to the in-gate 360. The bowl may also house a filter 320 in an alternative configuration. Different embodiments may use any number of filters in any particular location or in any particular configuration. The filter used in some embodiments may comprise polystyrene foam or sponge-like material and may be of any suitable shape or configuration.

FIG. 5 is another partial perspective view of components of a wheel manufacturing assembly according to certain embodiments. The wheel manufacturing assembly 400 of fig. 5 is similar to the respective wheel manufacturing assemblies 10, 100, 200, and 300 of fig. 1, 2, 3, and 4, but includes a riser portion 410, a riser sleeve 412, and a crusher core 420.

Riser sleeve 412 insulates riser section 410, which riser section 410 is formed by molten alloy flowing out through the casting cavity and back up through riser sleeve 412 and solidifying. The riser portion 410 may solidify after solidification of the adjacent cavity flange portion, which assists in reducing porosity of the wheel flange portion of the cast wheel by providing molten alloy to the cavity flange portion as the molten alloy solidifies. In the illustrated embodiment, a riser sleeve 412 is placed along the perimeter of the cavity plate portion adjacent to the cavity flange portion. Such a configuration may allow for a more uniform distribution of molten alloy during solidification and may increase the likelihood of avoiding casting irregularities in the section of the wheel flange portion. Other embodiments may use one or more riser sleeves 412 in alternative configurations.

The crusher core 420 is positioned on the base of the riser sleeve 412 and riser section 410 adjacent the cavity flange section and cavity plate section of the wheel cavity. In particular embodiments, the breaker core 420 comprises resin cured sand, such as 3-part resin cured sand, which includes silica sand made by a phenolic urethane process. The crusher core reduces the diameter of the riser part where it attaches to the casting wheel. The riser portion may be removed by tapping with a hammer or other instrument, causing the crusher core and adjacent riser to fall off leaving behind an alloy slug. The alloy lumps remaining after removing the crusher 420 and the riser part 410 may be machined away during the manufacturing process to complete the manufacture of the wheel. Removing the nuggets may require less machining than a full diameter riser and may help maintain the profile of the wheel plate portion of the cast wheel. Various embodiments may use any suitable number of breaker cores in conjunction with all or some of the risers of the assembly configured in any suitable configuration.

FIG. 6 is a perspective view of a filtration system of a wheel manufacturing assembly, according to certain embodiments. The filtration system 500 of fig. 6 can be used as a filter as described herein with respect to various embodiments, such as the filter 320 of fig. 4. The filtration system 500 includes a filter 510 and a conveyor belt 530. The molten alloy enters the filter system 500 and into the interior conveyor space created between the filters 510, passes through the filters, and then enters the wheel casting cavity (depicted by arrow 520). The filter system 500 helps reduce inclusions carried by the molten alloy and facilitates laminar flow of the alloy before the alloy enters the casting cavity. In some embodiments, the filtration system can include more or fewer filters, and the filters can be configured to create an interior space of any suitable shape. Various embodiments may use one or more filtration systems, and the one or more filtration systems may be oriented in any suitable position with respect to the wheel casting cavity. In some embodiments, a similar filtration system without an outer conveyor belt may be used, and in other embodiments, other types of conveyor belts may be used.

In various embodiments, the casting cavities may be oriented in the upper and lower dies such that the wheel plate cavities are either convex or concave relative to the upper dies. The illustrated embodiment uses a casting cavity that is recessed relative to the upper die. In this embodiment, the riser sleeve 412 is positioned in the upper mold adjacent to the cavity plate portion and the cavity flange portion such that the riser portion 410 will be formed along the wheel plate portion of the wheel adjacent to the wheel flange portion of the wheel. The curvature of the cavity plate portion in the upper mold in the illustrated embodiment facilitates the formation of the riser portion 410 adjacent the concave side of the cavity plate portion of the wheel cavity. Other embodiments may use other placements.

Although the present invention has been described with reference to particular embodiments, it should be understood that various other changes, substitutions, and alterations may be made hereto without departing from the spirit and scope of the present invention. For example, while particular embodiments of the present disclosure have been described with reference to a number of elements included within a wheel manufacturing assembly, these elements may be combined, reconfigured or positioned to accommodate particular casting requirements or requirements. For example, the wheel cavity portion may be configured differently within the mold and the casting cavity may be oriented within the mold in a concave or convex manner or in any other advantageous manner. In particular embodiments, the molten alloy may enter the casting cavity via a sprue positioned within the core assembly (a sprue configured to have a gating system including any number of in-gates of any suitable configuration), or via an alternative configuration, and may enter the upper and lower molds from any direction. In various embodiments, the upper or lower dies may be constructed of greensand or other material. The mold may include a cooling component, which may comprise steel, graphite, other metals or alloys, or other materials, and may provide the desired directional solidification in the wheel cavity. Further, in some embodiments, an insulator may be used adjacent to any portion of the wheel cavity or wheel manufacturing assembly to assist in controlling temperature during solidification. In particular embodiments, the riser may be positioned adjacent to the wheel cavity or any portion of the wheel manufacturing assembly and configured in any configuration to provide molten alloy to the wheel cavity as the cast wheel solidifies. A riser breaker core may also be employed adjacent to any number of risers to reduce the diameter of the attachment point between the riser and the casting wheel. In some embodiments, one or more filters may be positioned within the upper or lower dies to reduce inclusions in the molten alloy prior to the molten alloy entering the casting cavity. The bowl may also be configured to reduce inclusions in the molten alloy. In particular embodiments, the filter and the bowl may be used together. Further, in some embodiments, a bowl may be positioned within the casting mold to reduce eddy currents in the casting cavity. In particular embodiments, the filters may also be arranged in any number and in any configuration to reduce turbulence in the molten alloy. In some embodiments, a basin and one or more filters may be used in combination to assist in reducing turbulence and maintaining laminar flow.

The different embodiments encompass great flexibility in the configuration of the wheel manufacturing assembly and its components. Further, while some embodiments have been described with respect to manufacturing rail wheels, other types of cast wheels may be manufactured using particular embodiments.

Claims (23)

1. A vehicle wheel manufacturing system, comprising:

an upper die portion including an inner upper die wall;

a lower die portion including an inner lower die wall;

the inner cope mold wall and the inner drag mold wall at least partially define a perimeter boundary of a wheel cavity, the wheel cavity comprising:

a cavity center portion configured to form a wheel center portion of a wheel upon solidification of a molten alloy in the cavity center portion;

a cavity plate portion configured to form a wheel plate portion of the wheel upon solidification of a molten alloy in the cavity plate portion; and

a cavity flange portion configured to form a wheel flange portion of the wheel upon solidification of molten alloy in the cavity flange portion; and

a cooling assembly positioned within the wheel cavity adjacent to the cavity flange portion, the cooling assembly configured to provide directional solidification of molten alloy in the wheel cavity from the cavity flange portion toward the cavity plate portion.

2. The system of claim 1, wherein the cope and drag mold portions comprise green sand.

3. The system of claim 1, further comprising a core assembly positioned within the upper and lower mold portions, the core portion configured to define a cylindrical bore in the wheel upon solidification of the molten alloy.

4. The system of claim 3, further comprising a sprue positioned within the core assembly, the sprue configured to receive molten alloy such that molten alloy flows downwardly through the sprue prior to entering the wheel cavity.

5. The system of claim 1, further comprising a gate section comprising one or more in-gates configured to direct molten alloy into the wheel cavity.

6. The system of claim 1, wherein the cooling assembly comprises graphite.

7. The system of claim 1, further comprising an insulating sleeve adjacent to the cavity plate portion.

8. The system of claim 1, further comprising a basin positioned within the lower mold portion and adjacent to the cavity center portion.

9. The system of claim 8, further comprising at least one filter positioned within the bowl, the at least one filter configured to reduce inclusions in the molten alloy prior to the molten alloy entering the cavity center portion.

10. The system of claim 1, further comprising at least one filter positioned in the drag mold portion, the at least one filter configured to reduce inclusions in the molten alloy prior to the molten alloy entering the cavity center portion.

11. The system of claim 1, further comprising:

at least one riser crusher core positioned adjacent to the cavity flange portion; and

riser sleeves positioned adjacent to each of the at least one riser crusher core, each riser sleeve configured to insulate a respective riser portion adjacent to the cavity flange portion of the wheel cavity.

12. A method of manufacturing a wheel, comprising:

positioning a cooling assembly within a wheel cavity, the wheel cavity including a perimeter boundary at least partially defined by an inner upper mold wall of an upper mold portion and an inner lower mold wall of a lower mold portion;

the wheel cavity includes:

a cavity center portion configured to form a wheel center portion of a wheel upon solidification of a molten alloy in the cavity center portion;

a cavity plate portion configured to form a wheel plate portion of the wheel upon solidification of a molten alloy in the cavity plate portion; and

a cavity flange portion configured to form a wheel flange portion of the wheel upon solidification of molten alloy in the cavity flange portion;

the cooling assembly is configured to provide directional solidification of molten alloy in the wheel cavity from the cavity flange portion toward the cavity plate portion;

closing the cope and drag mold portions with the cooling assembly positioned in the wheel cavity; and is

At least partially filling the wheel cavity with a molten alloy that solidifies to form the wheel.

13. The method of claim 12, wherein the cope and drag mold portions comprise green sand.

14. The method of claim 12, further comprising positioning a core assembly within the upper and lower mold portions, the core portion configured to define a cylindrical bore in the wheel upon solidification of the molten alloy.

15. The method of claim 14, further comprising positioning a sprue within the core assembly, the sprue configured to receive molten alloy such that molten alloy flows downwardly through the sprue prior to entering the wheel cavity.

16. The method of claim 12, further comprising forming a gate section comprising one or more in-gates configured to direct molten alloy into the wheel cavity.

17. The method of claim 12, wherein the cooling assembly comprises graphite.

18. The method of claim 12, further comprising positioning an insulating sleeve adjacent to the cavity plate portion.

19. The method of claim 12, further comprising forming a basin within the drag mold portion and adjacent to the cavity center portion.

20. The method of claim 19, further comprising positioning at least one filter within the bowl, the at least one filter configured to reduce inclusions in the molten alloy prior to the molten alloy entering the cavity center portion.

21. The method of claim 12, further comprising positioning at least one filter in the drag mold portion, the at least one filter configured to reduce inclusions in the molten alloy prior to the molten alloy entering the cavity center portion.

22. The method of claim 12, further comprising:

positioning at least one riser breaker core adjacent to the cavity flange portion; and

positioning a riser sleeve adjacent each of the at least one riser crusher core, each riser sleeve configured to insulate a respective riser portion adjacent the cavity flange portion of the wheel cavity.

23. A rail wheel, comprising:

a wheel center portion formed after solidification of the molten alloy in the cavity center portion of the wheel cavity;

a wheel plate portion formed after solidification of the molten alloy in the cavity plate portion of the wheel cavity; and

a wheel flange portion formed after solidification of the molten alloy in the cavity flange portion of the wheel cavity;

wherein the wheel cavity is at least partially defined by an inner wall of the cope and drag mold portions; and is

Wherein the wheel cavity includes a cooling assembly positioned within the wheel cavity adjacent to the cavity flange portion, the cooling assembly configured to provide directional solidification of the molten alloy in the wheel cavity from the cavity flange portion toward the cavity plate portion.