Cast system

Abstract

Cast system (10), comprising: a casting (12) for a motor vehicle with an inner section, several middle sections (34) that are individually positioned in one of several areas of the inner section and are completely enclosed by a metal of the casting (12), and an insert part (36) positioned in one of the several middle sections (34), wherein the insert part (36) has a higher melting point than the melting point of the metal of the casting (12) that is displaced by the insert part (36), characterized by the fact that the insert part (36) comprises an internal bore (64) which is filled with at least one filling material (66), the filling material (66) is agricultural waste material.

Description

INTRODUCTION

[0001] The present disclosure relates to metal casting, in particular to the casting of aluminum parts. Reference is made to US 2020 / 0 406 674 A1 as prior art.

[0002] When casting automotive parts, a mold is typically created with a filler sand material to create a casting geometry. After the casting process is complete, it is often difficult to remove all the sand from the cast part, especially for complex geometric components such as cast automotive wheels, e.g., aluminum cast wheels. Therefore, casting sand removal paths are incorporated wherever possible to make casting sand removal more reproducible. However, sand casting is not a viable option for locations within a cast part with complex geometry where no path for sand removal is available after casting is complete. Alternative casting methods are therefore desirable.

[0003] It is also desirable to reduce or minimize the overall volume and weight of the cast material, such as aluminum, to reduce the weight and cost of a cast component without compromising the strength of the cast component. Incorporating voids into a cast component has been shown to result in weight and cost savings; however, voids in a cast component can create stress zones in the finished component under load.

[0004] While current automotive casting systems serve their purpose, there is a need for a new and improved metal casting system. SUMMARY

[0005] The present invention is defined by the appended independent claim 1. Advantageous further developments are given in the following description and in the dependent claims.

[0006] According to the invention, a cast system comprises a casting for a motor vehicle having an inner section. A plurality of central sections are individually positioned within one of a plurality of regions of the inner section that are completely enclosed by a metal of the casting. An insert is positioned within individual ones of the plurality of central sections. The insert has a higher melting point than the melting point of the metal of the casting that is displaced by the insert.

[0007] Preferably, the insert part defines a glass material and the casting defines a cast wheel.

[0008] Preferably, the insert comprises a length that maximizes the volume of the plurality of central sections, and the insert is spaced inwardly from a raised edge of the cast wheel and positioned at a depth from an outer surface of the cast wheel.

[0009] Preferably, the insert includes a first tapered end and an opposite second tapered end to assist in positioning and retaining the insert in a mold cavity prior to casting the metal of the cast wheel.

[0010] Preferably, the insert part comprises a first wire rod extending outwardly from the first tapered end and a second wire rod extending outwardly from the second tapered end.

[0011] Preferably, the first wire rod and the second wire rod are held in place in a final casting state of the cast wheel.

[0012] According to the invention, the insert part comprises an inner bore which is filled with at least one filling material.

[0013] Preferably, the at least one filler material has a different density than the metal of the casting displaced by the insert part and a higher melting point than the metal of the casting displaced by the insert part in order to produce a locally lower filling density within the casting.

[0014] Preferably, the insert part has a density that is less than or equal to the density of an equal volume of the metal of the casting that is displaced by the insert part.

[0015] Preferably, the casting comprises a cylindrical hub secured to a spoke cross portion, and wherein the casting defines a cast wheel having a plurality of spokes defining the inner portion, individual ones of the plurality of spokes comprising one of the plurality of middle portions.

[0016] Preferably, a casting comprises a cast wheel for a motor vehicle having a plurality of spokes, wherein individual ones of the plurality of spokes are substantially identical to the other ones of the plurality of spokes and are equidistant from a subsequent one of the plurality of spokes to maintain even weight distribution. Individual ones of the plurality of spokes extend inwardly from a raised bead of a spoke cross portion to a centrally disposed axle receiving portion. A central portion of individual ones of the plurality of spokes is completely enclosed by a metal of the plurality of spokes. An insert made of glass material is positioned in individual ones of the central portions, the insert having a higher melting point than the melting point of a metal of the cast wheel that is displaced by the insert.

[0017] Preferably, some of the insert parts comprise an inner bore which is filled with at least one filling material.

[0018] Preferably, the filler material has a different density than the metal of the cast wheel in order to produce a locally lower fill density within the cast wheel.

[0019] According to the invention, the filling material comprises an agricultural waste material.

[0020] Preferably, the insert remains permanently in place throughout the service life of the cast wheel and is held in a specific position.

[0021] Preferably, the insert comprises at least one wire extending outwardly from one end of the insert to serve as a retaining member that holds the insert in the specific location.

[0022] Preferably, the insert is sealed to ensure that a filler material in a cavity of the insert cannot contaminate the metal of the cast wheel. The air present in the insert is vented to a lower internal pressure before sealing to allow the filler material to outgas due to the heat of casting.

[0023] According to several aspects, a method for creating a locally lower filling density within a cast wheel comprises casting a cast wheel for a motor vehicle comprising a plurality of spokes, wherein individual ones of the plurality of spokes are substantially identical to the other ones of the spokes, extending individual ones of the plurality of spokes inwardly from a raised bead of a spoke cross portion to a centrally located axle receiving portion, completely enclosing a central portion of individual ones of the spokes with a metal of the spokes, and positioning an insert member within individual ones of the central portions, wherein the insert member defines a glass material having a higher melting point than a melting point of a metal of the cast wheel that is displaced by the insert member, and wherein the insert member permanently remains in place and is held in a particular location for a lifetime of the cast wheel.

[0024] In another aspect of the present disclosure, the method further comprises extending at least one wire outwardly from one end of the insert to serve as a retaining member that holds the insert in the particular location after casting the cast wheel.

[0025] In another aspect of the present disclosure, the method further comprises positioning a filler material in a cavity of the insert, sealing the insert to ensure that the filler material in the cavity cannot contaminate the metal of the cast wheel, and venting the air present in the insert to a lower internal pressure prior to sealing the insert to allow outgassing of the filler material due to the heat of casting.

[0026] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. Fig. 1 shows a cast wheel with a plurality of glass devices embedded in the casting according to an exemplary aspect in a perspective front view. Fig. 2 shows a cross-sectional view along line 2 of Fig. 1. Fig. 3 shows a glass device of the present disclosure in a front view. Fig. 4 shows the glass device of Fig.3 in a perspective cross-sectional end view. Fig. 5 shows another glass device of the present disclosure in a front perspective view. Fig. Figure 6 shows a cross-sectional front view along line 6 of Fig. 5. Fig. 7 shows another glass device of the present disclosure in a front perspective view. Fig. Figure 8 shows a cross-sectional front view along line 8 of Fig. 7. DETAILED DESCRIPTION

[0028] The following description is merely exemplary and is not intended to limit the present disclosure, application, or uses.

[0029] With reference to Fig.1, a casting system 10, according to one exemplary aspect, provides a casting that may be, for example, a cast wheel 12 for a motor vehicle. The cast wheel 12 has an inner portion defining a plurality of spokes, which in certain aspects include a first spoke 14, a second spoke 16, a third spoke 18, a fourth spoke 20, a fifth spoke 22, and a sixth spoke 24. The number of spokes may be more or fewer than the six spokes depicted, at the discretion of the wheel designer, and may include a ten (10) spoke embodiment that also includes spokes 24a, 24b, 24c, and 24d. The spokes are each substantially identical to the other spokes and are spaced equally apart from one subsequent spoke to maintain an even weight distribution which ensures that the cast wheel 12 is balanced.Individual spokes extend inwardly from a raised bead 26 of a spoke cross section 28 to a centrally disposed axle receiving section 30. The spoke cross section 28 is attached to a cylindrical hub 32.

[0030] It is known that the dynamic loading of the wheel during operation of a motor vehicle is high in the cylindrical hub 32 and lowest in the central sections 34 of the individual spokes, which define regions of the inner section and are completely enclosed by a metal of the casting. It may be advantageous to remove metal in the central sections 34 to minimize the overall wheel weight and wheel cost, for example, by leaving voids in the cast spokes that define the central sections 34. The central sections 34 are completely enclosed by the metal of the spokes. Since wheel casting of metals such as aluminum or magnesium is typically done by sand casting, sand would be used to create the voids.Therefore, access must be provided to remove the sand from the cast component after the casting process is complete to allow for the cavities within the cast component. Enclosed areas in the spokes, such as the center sections 34, cannot be easily removed of sand after the casting process.

[0031] It is therefore desirable to place a permanently held fixed volume element in the middle sections 34 instead of the sand. The fixed volume element, which is to be determined with reference to Fig. 2 to 8, should have a higher melting point than the metal it replaces and a density less than or equal to the density of the same volume of wheel metal such as aluminum or magnesium.

[0032] With reference to Fig. 2 and again referring to Fig.1 defines the fixed volume element to reduce the overall weight and cost of the cast wheel 12, an insert 36 positioned within individual ones of the central sections 34. The insert 36 has a higher melting point than the melting point of the metal of the casting displaced by the insert. The insert 36 has a length 38 that maximizes the volume of the central sections 34. Individual ones of the inserts 36 are spaced 42 inwardly from a raised rim 40 of the cast wheel 12 and are positioned a depth 44 below an outer surface 46 of the cast wheel 12. The insert 36 is generally thicker than the wall thickness 48 of the cylindrical hub 32, and therefore the inserts 36 are not positioned within the walls of the cylindrical hub 32.

[0033] With reference to Fig.3, the insert part 36 comprises, according to several aspects, a body made, for example, from a glass material that has a higher melting point than the metal it displaces, such as aluminum or magnesium. The glass material may be made from mixed waste glass that is not currently recycled or reused. The glass material may also be a ceramic material or made from unprocessed material. A shape of the insert part 36 may, as in Fig. 3, as an ampoule with a glass cylindrical body part 50, a tubular body part, as described with reference to Fig. 4, a capsule as described with reference to Fig. 5, and a torus, as shown in Fig. 7 shown, will be described.

[0034] With further reference to Fig.3, to assist in positioning and retaining the insert 36 within the mold cavity prior to metal casting, the insert 36 may include a first tapered end 52 and an opposite second tapered end 54. Further retention capability may also be provided by extending a first wire rod 56 outwardly from the first tapered end 52 and extending a second wire rod 58 outwardly from the second tapered end 54. The first tapered end 52, the second tapered end 54, the first wire rod 56, and the second wire rod 58 are held in place in the as-cast state of the cast wheel 12.

[0035] With reference to Fig. 4 and again referring to Fig.1 to 3, the insert 36 may also define a glass hollow sleeve 60 with a wall thickness 62 defining an internal bore 64 capable of maintaining an internal pressure less than or greater than ambient pressure. The internal bore 64 may also be filled with at least one filler material 66 having a different density than the cast metal and a higher melting point than the metal it is replacing to create a locally lower fill density within the cast wheel 12. The internal bore 64 of the insert 36 is internally sealed to prevent crushing of the insert 36 during mold assembly and subsequent metal casting. The filler material 66 may have a lower or higher density than the casting material. According to the invention, the filler material 66 is agricultural waste material, e.g. E.g. coconut fibers, fibers from corn stalks, animal hair, walnut shell flour, cocoa shell flour or rice husk waste.

[0036] With reference to Fig. 5, the insert part 36 can also define a vitreous capsule 68.

[0037] With reference to Fig. 6 and again referring to Fig. 5, the vitreous capsule 68 may have a first outer wall 70 and an oppositely directed second outer wall 72. A first end wall 74 is disposed opposite a second end wall 76, and both end walls are oriented transversely to the outer walls. An enclosed cavity 78, similar to that described with reference to Fig. 4, may be filled with at least one filler material 80 having a different density than the cast metal and a higher melting point than the metal it replaces in order to produce a locally lower fill density in the cast wheel 12.

[0038] With reference to Fig.7, the insert 36 may also define a vitreous torus 82. The vitreous torus 82 includes a hollow central bore that contains no filler material.

[0039] With reference to Fig. 8 and again referring to Fig. 7, the vitreous torus 82 comprises a circular body 86 with an enclosed cavity 88. The enclosed cavity 88 may contain a filler material 90 having a different density than the casting material and a higher melting point than the metal it replaces to create a locally lower fill density within the casting wheel 12.

[0040] Materials that may be used for the system and method of the present disclosure are shown in Table 1 below, where they are compared to the properties of aluminum, which is a common material for manufacturing wheels for automobiles. TABLE 1 material source Waste stream Organic content Recycled content Density (g / cm 3 ) Coconut fibers coconut X X ~1,40 Fibers from corn stalks corn X X 0,1275 Hair fibers - sheep / reindeer Agriculture / Animal Husbandry X X ~1,314 Walnut shell flour walnut X X 0,45-0,065 Cocoa shell flour cocoa X X 0,35 Rice husk waste rice X X 0,34-0,4 aluminum 2,67-2,7

[0041] A casting system 10 and method for creating a locally lower fill density in a casting wheel of the present disclosure provides for the use of a glass device disposed in an ampoule, capsule, torus, or cylinder, containing an inert filler made of agricultural waste material that has a higher melting point than the metal it is replacing to create a locally lower fill density in the casting. The casting is configured such that the insert 36 remains in place throughout the life of the casting, maintaining the insert 36 in a specific location. The insert 36 may be hollow or filled with a material that has a different density than the casting material (e.g., aluminum or magnesium). The insert 36 is configured such that the filler (if used) cannot interact with the molten metal during the casting process.According to the invention, the filler material consists of materials typically considered agricultural waste products. To reduce the casting mass, the filler has a lower density than the metal to be displaced, creating a locally lower fill density in the finished casting. This localized density reduction reduces excess casting mass and diverts waste from landfills, thereby improving the sustainability of the casting process. The use of denser waste material can also serve to alter the resonant frequency of the casting to dampen structure-borne noise.

[0042] The insert 36 is sealed to ensure that any filler material present cannot contaminate the casting material. The air present in the insert 36 can be released to a lower internal pressure before sealing to allow the filler material to outgas due to the heat of the casting process. The air can also be displaced by a gas that prevents the filler material from outgassing due to the heat of the casting process.

[0043] The casting is designed so that the glass device remains at a specific location in the casting throughout its lifetime. According to several aspects, this is achieved by means of a wire or a rod, hereinafter the first and second rods 56, 58, which are described with reference to Fig.3, which is a compatible alloy added to the tapered ends 52, 54 of the insert 36, which then bond to the mold cavity to hold the insert 36 in place during the subsequent casting process. In several aspects, a single wire may replace the first and second rods 56, 58 and extend completely through the insert 36. The tapered ends 52, 54 of the insert 36 may also be configured so that the shape of the insert 36 itself functions in the same manner as the first and second rods 56, 58. The insert 36 may be used with current core insertion technology for semi-permanent molds or sand castings. The insert 36 may also be used in low- and high-pressure die casting processes.

[0044] The system and method of the present disclosure, using one or more of the inserts 36, changes the bulk density of a metal casting in a localized area by displacing a portion of the cast metal corresponding to a volume of the insert 36 and replacing that metal with another, lower-cost, lower-density material.

[0045] Part mass reduction and sustainability in the part creation process are required. The system and method of the present disclosure reduce the mass of required casting material by changing the density in low-stress areas of the casting, replacing a load of material with lower-density material or materials that would otherwise have been discarded, thus supporting sustainability goals.

[0046] The system and method of the present disclosure offer several advantages. These include a system of glass inserts 36 that provide a reduction in the amount of metal used in a casting, representing both a cost and mass savings achieved through the use of a lower fill density. Another advantage is the use of materials from the waste stream to achieve the lower fill density, which helps these components achieve sustainability and landfill volume reduction goals.

Claims

[1] Cast system (10) comprising: a casting (12) for a motor vehicle having an inner section, a plurality of central sections (34) individually positioned in one of a plurality of regions of the inner section and completely enclosed by a metal of the casting (12), and an insert part (36) positioned in a single one of the plurality of central sections (34), the insert part (36) having a higher melting point than the melting point of the metal of the casting (12) displaced by the insert part (36), characterized by , that the insert part (36) comprises an inner bore (64) which is filled with at least one filling material (66), wherein the filling material (66) is agricultural waste material. [2] The cast system (10) of claim 1, wherein the insert (36) defines a glass material and the casting (12) defines a cast wheel. [3] A cast system (10) according to claim 2, wherein: the insert part (36) has a length that maximizes the volume of the plurality of middle sections (34), and the insert part (25) is arranged inwardly from a raised edge (40) of the cast wheel (12) at a distance (42) and positioned at a depth from an outer surface (46) of the cast wheel (12). [4] The cast system (10) of claim 2, wherein the insert (36) includes a first tapered end (52) and an opposite second tapered end (54) to assist in positioning and retaining the insert (36) in a mold cavity prior to casting the metal of the cast wheel (12). [5] The cast system (10) of claim 4, wherein the insert member (36) comprises a first wire rod (56) extending outwardly from the first tapered end (52) and a second wire rod (58) extending outwardly from the second tapered end (54). [6] The cast system (10) of claim 5, wherein the first wire rod (56) and the second wire rod (58) are held in place in a final casting condition of the cast wheel (12). [7] The cast system (10) of claim 1, wherein the at least one filler material (66) has a different density than the metal of the casting (12) displaced by the insert (36) and a higher melting point than the melting point of the metal of the casting (12) displaced by the insert (36) to create a locally lower fill density within the casting (12). [8] The cast system (10) of claim 1, wherein the insert (36) has a density less than or equal to the density of an equal volume of the metal of the casting (12) displaced by the insert (36). [9] The cast system (10) of claim 1, wherein the casting (12) includes a cylindrical hub (32) attached to a cross spoke portion (28), and wherein the casting (12) defines a cast wheel having a plurality of spokes (14, 16, 18, 20, 22, 24, 24a, 24b, 24c, 24d) defining the inner portion, individual ones of the plurality of spokes (14, 16, 18, 20, 22, 24, 24a, 24b, 24c, 24d) having one of the plurality of central portions (34).

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