Patent Application
20180017016
This disclosure relates generally to magnetic insert retention in die cast tooling. More particularly, the disclosure relates to magnetic insert retention and position control for over-molded inserts in die cast tooling for an engine block.
Die cast components can be configured to incorporate over-molded (cast-in-place) inserts that provide certain attributes that are not attainable in a bulk cast media, or which are not feasible to create in the cast tooling process. The insert can be positioned and retained within the tooling via tooling design features. However, certain types of components provide unique challenges for over-molded inserts.
One such component is a cast-in-place main journal, also known as a “bulkhead insert,” for a high pressure die cast engine block. The geometry of the insert is such that it cannot be secured within the tooling without the use of opposed die halves. The use of opposing die halves to secure the insert presents the risk of collision between the halves that could potentially damage the tooling or produce a part with a compromised insert that may be difficult to detect in the finished casting operation.
A casting assembly for an engine block according to an exemplary aspect of the present disclosure includes, among other things, an insert and at least one magnet configured to retain the insert in a predefined position within an engine block mold cavity.
In a further non-limiting embodiment of the foregoing casting assembly, the insert comprises a bulkhead insert defining an engine crank bore.
In a further non-limiting embodiment of any of the foregoing casting assemblies, the magnet comprises an electromagnet or permanent magnet.
In a further non-limiting embodiment of any of the foregoing casting assemblies, an electrical circuit cooperates with the at least one magnet to detect a presence of the insert in the engine block mold cavity.
In a further non-limiting embodiment of any of the foregoing casting assemblies, the engine block is aluminum and the insert comprises a material other than aluminum.
In a further non-limiting embodiment of any of the foregoing casting assemblies, the material of the insert comprises a ferrous material.
In a further non-limiting embodiment of any of the foregoing casting assemblies, a cooling circuit cools the at least one magnet if a temperature of the magnet exceeds a predetermined temperature.
In a further non-limiting embodiment of any of the foregoing casting assemblies, the engine block mold cavity is provided within a die, and wherein the die includes a bore configured to receive the magnet, and wherein the cooling circuit is at least partially received within the bore.
In a further non-limiting embodiment of any of the foregoing casting assemblies, there is at least one temperature sensor to determine the temperature of the magnet.
An engine block casting method according to an exemplary aspect of the present disclosure includes, among other things, positioning at least one insert in a mold cavity, retaining the insert in position with at least one magnet, introducing material into the mold cavity to form an engine block, and solidifying the material to secure the insert within the engine block.
In a further non-limiting embodiment of the foregoing method, the material comprises aluminum and the insert is comprised of a material other than aluminum.
In a further non-limiting embodiment of any of the foregoing methods, the material of the insert comprises a ferrous material.
In a further non-limiting embodiment of any of the foregoing methods, the insert comprises a bulkhead insert defining an engine crank bore.
In a further non-limiting embodiment of any of the foregoing methods, the method includes detecting a presence of the insert in the mold cavity prior to introducing material into the mold cavity via an electrical circuit that cooperates with the at least one magnet.
In a further non-limiting embodiment of any of the foregoing methods, the at least one insert comprises at least two inserts and including retaining each insert in position with at least one magnet.
In a further non-limiting embodiment of any of the foregoing methods, the at least two inserts comprise a first bulkhead insert and a second bulkhead insert that each define an engine crank bore.
In a further non-limiting embodiment of any of the foregoing methods, the method includes cooling the at least one magnet if a temperature of the magnet exceeds a predetermined temperature.
In a further non-limiting embodiment of any of the foregoing methods, the magnet comprises an electromagnet or permanent magnet.
A vehicle component casting method according to an exemplary aspect of the present disclosure includes, among other things, positioning at least one insert in a mold cavity, retaining the insert in position with at least one magnet, cooling the magnet if a temperature of the magnet exceeds a predetermined temperature, and introducing material into the mold cavity to form a vehicle component.
In a further non-limiting embodiment of any of the foregoing methods, the vehicle component is an engine block.
The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows:
This disclosure relates generally to an engine block having a main journal. To create the main journal within the engine block, the engine block is cast about an insert that is referred to as bulkhead insert. The engine block is formed within a die that is configured to hold the insert in a desired position within the die such that the insert can be cast-in-place, i.e. over-molded.
In one example shown in
In the example shown in
In one example, the magnet 24 comprises a permanent magnet. In another example, the magnet 24 comprise an electromagnet. As known, permanent magnets create their own magnetic field while electromagnets produce magnetic fields only through the application of electricity. When using a permanent magnet, the magnet should provide sufficient magnetic force to retain the insert 12 in the desired position during the casting process. The electromagnet offers the advantages of being about to control the level of the magnetic force as wells as providing on/off control.
The magnets 24 are positioned within the second cavity 22, which is aligned with the first cavity 20 that receives the insert 12. An electronic control unit 32 is associated with the magnets 24 to detect a presence of the insert 12 in the die 10 prior to introducing material into the die cavity 16. During the casting process, the inserts 12 are placed within the cavity 20 and tightly held in the correct orientation by the magnets 24. Once the presence of the inserts 12 is detected, material is then poured into the die cavity 16 around the inserts 12 and the casting process takes place in a known manner.
An example electrical circuit 36 is shown in
An example electrical circuit 38 is shown in
In one example, the magnet 24 is cooled by a cooling circuit 40 that is housed within the die 10. The magnet 24 can be cooled if a temperature of the magnet 24 exceeds a predetermined temperature. The predetermined temperature is preferably set at a temperature that would be below a temperature that would degrade the magnetic force capability of the magnet.
As shown in
The cooling lance 44 includes an input path 50 that is used to direct a cooling fluid, such as water for example, into the cavity 22 to cool the magnet 24, and includes an output path 52 that draws heated fluid out of the cavity 22. It should be understood that while
Using the magnets 24 to retain the inserts 12 within a single die 10 offers several advantages over prior tooling configurations. With prior configurations, in order to retain the bulkhead insert within the die, the insert had to be captured by extending a die piece through the cavity steel insert and main journal through hole of the bulkhead insert to lock it into place. This traditional approach is typical for cast-in cylinder liners, steering wheel armature hubs, and other examples where a mandrel or pin can retain the insert in the die draw. The disadvantage with this configuration is that the movement of the retention piece would be out of die draw, which would make die construction more complex and expensive, and would also increase maintenance requirements and costs in operation. Additionally, the position of the insert is critical for function of the engine, and the required clearances to allow proper function of the retaining die piece would not provide tight tolerance on location or position of the insert. Further, the required clearances would provide opportunity for flashing of molten aluminum to jam or lock the die components.
Using magnets to retain the insert in the correct position provides a configuration where there are no moving parts and no opportunity for flash related complications. Further, the magnets provide the ability to locate the insert tightly off of a single die piece (the same die piece where upper journal halves would be cast in a typical high pressure die cast engine block). Further, the use of a cooling circuit to cool the magnet prevents operating temperatures from exceeding the optimal temperature range of the magnet.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims.
