VALVE SEAT RING

Abstract

The invention relates to a highly heat conductive valve seat ring (1) comprising a carrier layer (2) and a functional layer (3), wherein the carrier layer (2) consists of a solidified copper matrix containing 0.10 to 20% w/w of a solidifying component s and the functional layer (3) consists of a solidified copper matrix which further contains, based on the copper matrix, 5 to 35% w/w of one or more hard phases.

Claims

1. Valve seat ring (1) comprising a carrier layer (2) and a functional layer (3), characterized in that the carrier layer (2) consists of a solidified copper matrix containing 0.10 to 20% w/w of a solidifying/strengthening component and the functional layer (3) consists of a solidified copper matrix which further contains, based on the copper matrix, 5 to 35% w/w of one or more hard phases.

2. Valve seat ring according to claim 1, characterized in that the solidifying component of the copper matrix is an oxide, in particular Al.sub.2O.sub.3 or Y.sub.2O.sub.3.

3. Valve seat ring according to claim 1, characterized in that the solidifying component of the copper matrix is an intermetallic phase, in particular containing Cu, Cr, Zr, Nb, Ni and/or Si.

4. Valve seat ring according to claim 1, characterized in that the solidifying component is Al.sub.2O.sub.3 or Cr.sub.2Nb.

5. Valve seat ring according to claim 1, characterized in that the hard phase of the functional layer is a hard phase based on iron, cobalt, nickel, a carbide, oxide and/or nitride.

6. Valve seat ring according to claim 5, characterized in that the hard phase is a hard phase based on iron, nickel or cobalt.

7. Valve seat ring according to claim 1, characterized in that the functional layer contains 0.1 to 5% w/w of a solid lubricant.

8. Valve seat ring according to claim 7, characterized in that the solid lubricant is MnS, MoS.sub.2, WS.sub.2, CaF.sub.2 or hexagonal BN.

9. Valve seat ring according to claim 1, characterized in that the dividing line between carrier layer (2) and functional layer (3) extends at an angle of 0 to 65, with the carrier layer (2) widening towards the outside.

10. Valve seat ring according to claim 9, characterized in that the dividing line extends at an angle of between 35 and 65.

11. Valve seat ring according to claim 1 having a thermal conductivity of the carrier layer (2) of 120 W/mK at 500 C.

12. Valve seat ring according to claim 11, characterized in that the thermal conductivity of the carrier layer (2)is 220 W/mK at 500 C.

13. Valve seat ring according to claim 1, characterized in that the thermal conductivity of the functional layer (3)is 70 W/mK at 500 C.

14. Valve seat ring according to claim 1 manufactured by powder metallurgical processes.

15. Method of manufacturing a valve seat ring according to claim 1, characterized by the following steps: Mixing the powders, Filling the powder of the carrier layer (2) into a molding die, Pre-compacting the powder of the carrier layer (2) if necessary, Filling the powder of the functional layer (3) into a molding die, Compacting the powder in the die, Sintering or subjecting the powder to HIP and Thermal or mechanical after-treatment of the sintered ring.

16. Method according to claim 15, characterized in that the powders are post-compacted and/or post-sintered after the first sintering step.

17. Method according to claim 15, characterized in that the sintering steps are carried out at a temperature of 850 C.

18. Method according to claim 14, characterized in that the compaction is carried out by means of CIP.

19. Valve seat ring according to claim 1 provided with a coating.

Description

[0049] The invention is explained in more detail by way of the enclosed figures.

[0050] FIG. 1 shows a valve seat ring 1 as proposed by the invention in cross sectional representation with a lower carrier layer 2 and a functional layer 3 arranged on it. The dividing line between the two layers is essentially horizontal.

[0051] FIG. 2 is a cross-sectional view through a valve seat ring 1 according to the invention with an inclined dividing line existing between the carrier layer 2 and the functional layer 3. The carrier layer 2 thus expands towards the outer edge and in this manner increases the contact surface with the surrounding cylinder head. This results in an improved heat flow to be achieved into the cooled cylinder head. Between the layers there is a transition area 4, in which the dividing line runs between the carrier layer 2 and the functional layer 3.

[0052] In FIG. 3 the thermal conductivity values of different materials within the scope of the invention are shown at different temperatures. The materials are as follows:

[0053] 1. A carrier material consisting of oxide-reinforced copper; [0054] 2. A functional material with 20% of a hard phase; [0055] 3. A functional material with 30% of a hard phase; [0056] 4. A functional material with 40% of a hard phase.

[0057] For all functional materials, the carrier matrix is the same as in the carrier material.