Iron-based sintered alloy valve seat for internal combustion engine

Patent metadata

Field	Value
Publication number	US-11549408-B2
Application number	US-201917054840-A
Country	US
Kind code	B2
Filing date	May 14, 2019
Priority date	May 15, 2018
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

Provided is a valve seat insert for an internal combustion engine, which has both an excellent heat dissipation property and excellent wear resistance. The valve seat insert for an internal combustion engine is used while being press-fitted into an aluminum alloy cylinder head, is made of an iron-based sintered alloy, is formed by integrating two layers of a functional member side layer and a supporting member side layer, and has a plating film on at least an outer peripheral side. The plating film is preferably a copper plating film. The plating film is a plating film having a thickness of 1 to 100 μm and a hardness of 50 to 300 HV, and the hardness of the plating film is adjusted so as to satisfy a range of 1.05 to 4.5 times hardness of the cylinder head in Vickers hardness HV. Pores contained in the valve seat insert are preferably sealed with a curable resin before plating treatment. Consequently, a valve seat insert for an internal combustion engine which does not go through complicated processes, is not accompanied by a significant decrease in wear resistance compared with the prior art, and has an excellent heat dissipation property is provided. If a roughened surface region is further formed at at least one portion on the outer peripheral surface of the valve seat insert in addition to the plating film, a falling out resistance property is improved. The same effect can be obtained even if the valve seat insert is a single layer of only the functional member side layer.

First claim

The invention claimed is:

1. An iron-based sintered alloy valve seat insert for an internal combustion engine which is a valve seat insert for an internal combustion engine to be press-fitted into an aluminum alloy cylinder head, the valve seat insert made of an iron-based sintered alloy comprising:
a single layer of only a functional member side layer, or integrated two layers of the functional member side layer and a supporting member side layer,
wherein a plating film is provided on at least an outer peripheral side, and a heat dissipation property is excellent,
wherein the plating film is a plating film having a thickness of 1 to 100 μm and a hardness of 50 to 300 HV in a Vickers hardness HV, and the hardness of the plating film satisfies a range of 1.05 to 4.5 times a hardness of the cylinder head in the Vickers hardness HV,
wherein the functional member side layer or the two layers of the functional member side layer and the supporting member side layer is/are layers formed by being subjected to a sealing hole treatment using a heat curing type resin or anaerobic resin, and
wherein the plating film is a copper plating film or a tin plating film.

2. The iron-based sintered alloy valve seat insert for an internal combustion engine according to claim 1 , wherein surface roughness of the plating film is 0.1 to 1.6 μm in arithmetic average roughness Ra in accordance with the provisions of JIS B 0601-1994.

3. The iron-based sintered alloy valve seat insert for an internal combustion engine according to claim 1 , wherein a concave-convex mixed portion having, in a direction perpendicular to a circumferential direction, a plurality of rows of concave-convexes where concaves and convexes extending in the circumferential direction are adjacent to each other is provided as a roughened surface region at at least one portion on an outer peripheral surface of the valve seat insert, and the roughened surface region is provided at an area ratio of 0.3% or more in total with respect to an entire region of the outer peripheral surface.

4. The iron-based sintered alloy valve seat insert for an internal combustion engine according to claim 3 , wherein when the concave-convex mixed portion is observed from a direction perpendicular to the outer peripheral surface, the concave-convex mixed portion has a triangular shape in a press-fitting direction, and an apex of the triangular shape facing the press-fitting direction has an apex angle of 10 to 150°.

5. The iron-based sintered alloy valve seat insert for an internal combustion engine according to claim 1 , wherein when the two layers of the functional member side layer and the supporting member side layer are integrated, the functional member side layer is 10 to 70% by volume with respect to a total amount of the valve seat insert.

6. The iron-based sintered alloy valve seat insert for an internal combustion engine according to claim 1 , wherein the functional member side layer has a matrix part in which hard particles are dispersed in a matrix phase, the matrix part has a matrix part composition containing C: 0.2 to 2.0% by mass and one kind or two or more kinds selected from among Co, Mo, Si, Cr, Ni, Mn, W, V, Cu, and S in a total amount of 50% by mass or less with the balance being Fe and unavoidable impurities, and a base matrix phase structure in which the hard particles are dispersed in the matrix phase in an amount of 5 to 40% by mass with respect to a total amount of the functional member side layer.

7. The iron-based sintered alloy valve seat insert for an internal combustion engine according to claim 1 , wherein the supporting member side layer has a matrix part composition containing C: 0.2 to 2.0% by mass or further containing one kind or two or more kinds selected from among Mo, Si, Cr, Ni, Mn, W, V, S, P, and Cu in a total amount of 20% by mass or less with the balance being Fe and unavoidable impurities.

8. The iron-based sintered alloy valve seat insert for an internal combustion engine according to claim 6 , wherein in addition to the base matrix phase structure, the functional member side layer further has a base matrix phase structure in which solid lubricant particles are dispersed in an amount of 0.5 to 4% by mass with respect to the total amount of the functional member side layer.

9. The iron-based sintered alloy valve seat insert for an internal combustion engine according to claim 7 , wherein the supporting member side layer further has a structure in which solid lubricant particles are dispersed in the matrix phase in an amount of 0.5 to 4% by mass with respect to a total amount of the supporting member side layer.

10. The iron-based sintered alloy valve seat insert for an internal combustion engine according to claim 2 , wherein a concave-convex mixed portion having, in a direction perpendicular to a circumferential direction, a plurality of rows of concave-convexes where concaves and convexes extending in the circumferential direction are adjacent to each other is provided as a roughened surface region at at least one portion on an outer peripheral surface of the valve seat insert, and the roughened surface region is provided at an area ratio of 0.3% or more in total with respect to an entire region of the outer peripheral surface.

Assignees

• Nippon Piston Ring Co Ltd

Inventors

• Oikawa Ayato
• Suwa Kiyoshi
• Ogawa Katsuaki
• Oshige Hiroshi
• Sato Kenichi

Classifications

• B22F2301/35

  Iron · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• C22C33/0285 Primary

  with Cr, Co, or Ni having a minimum content higher than 5% · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title

• C25D3/38

  of copper · CPC title