Internally cooled valve having a valve bottom, and method for the production thereof
A method for manufacturing an internally cooled valve ( 2 ), includes providing a valve body ( 4 ) having a valve stem ( 6 ) that ends in a valve head ( 8 ). The valve body ( 4 ) has a cavity ( 10 ) that is open toward the valve head ( 8 ) and with a valve base element ( 12 ) by friction welding the valve base element ( 12 ) to the valve head ( 8 ). The valve bottom element ( 12 ) is preferably a sintered component.
1. A method for manufacturing an internally cooled valve, comprising providing a valve body having a valve stem that ends in a valve head, wherein the valve body has a cavity that is open toward the valve head, providing a valve base element, and closing the cavity with the valve base element by friction welding the valve base element to the valve head,
wherein the valve base element and/or the valve body have/has an engagement structure with which the valve base element and/or the valve body are/is centrally clamped, and/or a torque is transmitted to the valve base element and/or to the valve body, and
wherein the valve base element is fabricated as a green compact or brown compact by metal powder injection molding and sintered and wherein the valve base element is provided with a cooling rib structure and/or flow-influencing structure on a surface facing the cavity.
2. The method according to claim 1 , wherein the friction welding is carried out as inductive friction welding.
3. The method according to claim 1 , further comprising at least partially filling the cavity with a coolant before the cavity is closed by friction welding.
4. The method according to claim 3 , wherein the coolant is selected from sodium or a sodium-containing coolant.
5. The method according to claim 1 , wherein the engagement structure is subsequently removed and/or ablated.
6. The method according to claim 1 , wherein the valve base element and the valve body have a welding surface contour, which in the friction welding operation produces a weld expulsion in the cavity in a desired shape of a cooling rib.
7. The method according to claim 6 , wherein an outer portion of the weld expulsion is subsequently removed.
8. An internally cooled valve having a valve body that includes a valve head and a valve stem, the valve body having a cavity extending into the valve head the cavity being closed by a valve base that is joined to the valve head by friction welding,
the valve base element and/or the valve body have/has an engagement structure with which the valve base element and/or the valve body may be centrally clamped, and a torque may be transmitted to the valve base element and/or to the valve body,
the valve base element being provided with a cooling rib structure and/or flow-influencing on a surface facing the cavity, and
wherein the valve base element is produced by sintering from a valve base element green compact or brown compact valve base element that is produced by metal powder injection molding.
9. The internally cooled valve according to claim 8 , including a friction weld expulsion on an inner side of the cavity having the shape of a cooling rib which allows improved heat transfer from the valve head to the coolant.
10. The internally cooled valve according to one of claim 8 , wherein the valve base element is produced by sintering.