Device and Method for Hot Stamping

This U.S. Non-Provisional patent application claims the benefit of and priority to U.S. Provisional Application Ser. No. 63/663,375 filed Jun. 24, 2024, the entire disclosure of which is hereby incorporated by reference in its entirety.

The invention relates generally to a device and method for hot stamping a steel component, such as a door for a vehicle.

This section provides background information related to the present disclosure which is not necessarily prior art.

Components formed from steel are often desired for use in vehicles. The method of manufacturing the component can include hot forming a steel blank to achieve a predetermined shape. The hot forming processes typically includes heating the blank in a furnace, and then transferring the heated blank to a forming device. The hot forming process next includes forming the blank in a die of the forming device while the blank is at a temperature ranging from 950° C. to 1250° C. followed by quenching the hot formed component in the die. The forming step preferably includes applying sufficient pressure to the component to achieve the desired shape and material properties. The quenching step preferably includes contacting the hot formed component with sections of the die which are cooled by a fluid, such as water cooling, to also achieve the desired material properties.

However, in some cases, the desired shape and/or material properties of the component require the die to present an angled forming surface that would create a backdraft condition, preventing the component from being removed from the forming device. In order to allow for removal of the component after the hot forming process, the die is designed for convenient removal of the component, but then post forming or secondary operations on the component are required outside of the forming device in order to achieve the desired shape and/or material properties. Thus, improvements to the forming device and method are desired.

One aspect of the disclosure provides a forming device for hot forming a component. The forming device includes an upper cam slide and a lower fill slide which form a desired shape of the component therebetween. The shape of the upper cam slide and lower fill slide allow for desired material properties to be obtained in the forming device, so that no post-forming or secondary operation outside of the forming device is required. The lower fill slide is capable of retracting after forming the component to the desired shape, so that the component can be removed from the forming device and a backdraft situation is avoided.

Another aspect of the disclosure provides a method of hot forming a component. The method includes forming a blank between an upper cam slide and a lower fill slide of a forming device. The upper cam slide and lower fill slide are designed to form a desired shape of the component therebetween. The shape of the upper cam slide and lower fill slide also allow the method to include obtaining desired material properties in the forming device, so that no post-forming or secondary operation outside of the forming device is required. The method further includes retracting the lower fill slide after forming the component to the desired shape, so that the component can be removed from the forming device and a backdraft situation is avoided.

One aspect of the disclosure provides a forming devicefor forming a component, and typically for hot forming a componentfrom a blank made of steel. The componentis typically designed for use in a vehicle, such as a door panel for an automotive vehicle. An example wherein the componentis the door panel is shown in. Portions of the example component are shown in. The shape of the example componentincludes a plurality of walls having complex shapes. At least two opposing walls of the componentare disposed at an angle that creates an undercut area. According to an example embodiment, the two walls form an angle ranging from 10 to 20 degrees, such as 15 degrees. This undercut areacould create a backdraft condition in a conventional die, preventing the componentfrom being removed from the die. Alternatively, if the conventional die were designed for convenient removal of the component, post forming or secondary operations outside of the conventional die would be required to achieve the desired shape and/or material properties. However, the forming devicedisclosed herein is advantageously designed to avoid the backdraft condition and allow for convenient removal of the component, while also achieving the desired shape and material properties in the component, without post-forming or secondary operations outside of the forming device.

As best shown in, the forming deviceincludes an upper cam slidewhich extends from an upper die and a lower fill slidedisposed above a lower die. The upper cam slidepresents an upper forming surfaceand the lower fill slidepresents a lower forming surfacewhich together form the componenthaving the desired shape and material properties. In the example embodiments, the upper forming surfacepresents a corner or pointed edge extending outward and toward the lower fill slide. The lower fill slidepresents a lower forming surfacefacing the upper forming surfaceand receiving the lower forming surfacewhen the forming deviceis in a closed position. The lower forming surfaceextends inward and away from upper cam slide. In other words, in the example embodiments, the lower forming surfacepresents a ledge, and the corner or pointed edge of the upper forming surfacerests on the ledge. The shapes of the surfaces,correspond to one another. As shown in, the direction of motion of the upper cam slideduring the forming process extends at an angle of about 30 to about 50 degrees, for example 40 degrees, relative to a line extending in a vertical direction (perpendicular to the ground). Also shown in, the direction of motion of the lower fill slideduring the forming process extends at an angle of about 20 to about 40 degrees, for example 30 degrees, relative to a line extending in a vertical direction (perpendicular to the ground).

The upper cam slideand the lower fill slideinclude a plurality of cooling holes for conveying a cooling fluid therethrough. The forming devicealso include a saw tooth driverdisposed beneath the lower fill slideand an upper padadjacent the upper cam slide. The upper padalso presents a pad surfacewhich engages the componentand helps to form the componentinto the desired shape.

The forming deviceis preferably used to hot form the steel blank into the componenthaving the desired shape and material properties. The hot forming process includes heating the blank, typically in a furnace, or another location outside of the forming device. The method next includes transferring the heated blank to the forming device, and forming the heated blank between the upper forming surfaceof the upper cam slideand the lower forming surfaceof the lower fill slidewhile the blank is at a high temperature, such as a temperature ranging from 950° C. to 1250° C. The upper cam slideand the lower fill slideare desired with dimensions that cause the componentto achieve the desired shape and/or material properties. The upper cam slideand the lower fill slidealso apply a sufficient pressure to the componentwhich allows the componentto achieve the desired shape and/or material properties. The upper and lower forming surfaces,of the upper cam slideand lower fill slideare designed at angles that depend on the desired shape of the component. In the example embodiment, wherein the componentis the door panel, the upper cam slideand the lower fill slideare able to create the undercut areain the component.

The method next includes quenching the hot formed componentbetween the upper cam slideand the lower fill slide. This step includes conveying the cooling fluid, such as water, through the cooling holes of the upper cam slideand the lower fill slide. The quenching step preferably includes contacting the hot formed componentwith certain sections of the upper cam slideand the lower fill slidewhich are cooled by the cooling fluid and at a sufficient pressure to achieve the desired material properties.

Due to the design of the forming device, the componentcan be easily removed from the forming deviceafter the hot forming process. The lower fill slide, which forms the undercut area, as well as the saw tooth driver, retract from the upper cam slideafter the forming process, as shown in, so that the componentcan be released from contact with the upper cam slideand thus can be removed from the forming device.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the disclosure.