Piston for internal combustion engines and method for producing piston for internal combustion engines

Patent metadata

Field	Value
Publication number	US-11008974-B2
Application number	US-201716069528-A
Country	US
Kind code	B2
Filing date	Jan 5, 2017
Priority date	Jan 12, 2016
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

This piston for internal combustion engines, which is capable of achieving high heat shielding properties and high durability, comprises: a base that is formed from aluminum or an aluminum alloy; a composite material part which is formed in a first region of the surface of the base, and which is formed from a composite material that is reinforced with inorganic fibers or whiskers; and an alumite coating film that is formed on the composite material part and a second region of the surface of the base, said second region being different from the first region.

First claim

The invention claimed is:

1. An internal-combustion-engine piston, comprising:
a base material formed from aluminum or an aluminum alloy and having a top surface that includes a first region, a second region, and a third region;
a composite material portion formed from a composite material reinforced by an inorganic fiber or a whisker and provided on the first region of the top surface of the base material; and
an anodized aluminum coating formed on a top surface and a radially innermost side surface of the composite material portion, the second region of the top surface of the base material, and the third region of the top surface of the base material, wherein:
prior to the anodized aluminum coating being formed on the top surface and the radially innermost side surface of the composite material portion, the second region of the top surface of the base material, and the third region of the top surface of the base material:
the second region of the top surface of the base material is set to be lower than the top surface of the composite material portion by a height difference in a vertical direction with respect to the second region of the top surface of the base material and the top surface of the composite material portion, and
the third region of the top surface of the base material is set to be further recessed than the radially innermost side surface of the composite material portion by a radial difference in a perpendicular direction to the third region of the top surface of the base material and the radially innermost side surface of the composite material portion, wherein
the height difference is determined based on a difference in anodization rate of the anodized aluminum coating on the top surface of the composite material portion and the second region of the top surface of the base material,
the radial difference is determined based on a difference in anodization rate of the anodized aluminum coating on the radially innermost side surface of the composite material portion and the third region of the top surface of the base material, and such that when the anodized aluminum coating is formed on the top surface of the composite material portion and the second region of the top surface of the base material,
a first thickness of the anodized aluminum coating formed on the top surface of the composite material portion is smaller than a second thickness of the anodized aluminum coating formed on the second region of the top surface of the base material by the height difference.

2. The internal-combustion-engine piston according to claim 1 ,
wherein a part of the anodized aluminum coating formed on the second region of the top surface of the base material includes a top surface at a same position in the vertical direction as a top surface of a part of the anodized aluminum coating formed on the top surface of the composite material portion.

3. A method for producing an internal-combustion-engine piston, the method comprising:
forming a base material from aluminum or an aluminum alloy, the base material having a top surface that includes a first region, a second region, and a third region;
forming a composite material portion from a composite material reinforced by an inorganic fiber or a whisker on the first region of the top surface of the base material;
prior to an anodized aluminum coating being formed on a top surface and a radially innermost side surface of the composite material portion, the second region of the to surface of the base material, and the third region of the top surface of the base material:
processing the second region of the top surface of the base material so that the second region of the top surface of the base material is lower than a top surface of the composite material portion by a height difference in a vertical direction with respect to the second region of the top surface of the base material and the top surface of the composite material portion, and
processing the third region of the top surface of the base material so that the third region of the top surface of the base material is further recessed than the radially innermost side surface of the composite material portion by a radial difference in a perpendicular direction to the third region of the top surface of the base material and the radially innermost side surface of the composite material portion; and
forming the anodized aluminum coating on the top surface and the radially innermost side surface of the composite material portion, the second region of the top surface of the base material, and the third region of the top surface of the base material, wherein:

the height difference is determined based on a difference in anodization rate of the anodized aluminum coating on the top surface of the composite material portion and the second region of the top surface of the base material;
the radial difference is determined based on a difference in anodization rate of the anodized aluminum coating on the radially innermost side surface of the composite material portion and the third region of the top surface of the base material; and
a first thickness of the anodized aluminum coating formed on the top surface of the composite material portion is smaller than a second thickness of the anodized aluminum coating formed on the second region of the top surface of the base material by the height difference.

4. The internal-combustion-engine piston according to claim 1 ,
wherein a third thickness of the anodized aluminum coating formed on the radially innermost side surface of the composite material portion is smaller than a fourth thickness of the anodized aluminum coating formed on the third region of the top surface of the base material by the radial difference.

5. The internal-combustion-engine piston according to claim 1 ,
wherein a part of the anodized aluminum coating formed on the third region of the top surface of the base material includes a radially innermost side surface at a same position in the perpendicular direction as a radially innermost side surface of a part of the anodized aluminum coating formed on the radially innermost side surface of the composite material portion.

6. An internal-combustion-engine piston, comprising:
a base material formed from aluminum or an aluminum alloy, having a top surface that includes a first region and a second region;
a composite material portion formed from a composite material reinforced by an inorganic fiber or a whisker and provided on the first region of the top surface of the base material; and
an anodized aluminum coating formed on a top surface of the composite material portion and the second region of the top surface of the base material, wherein:
prior to the anodized aluminum coating being formed on the top surface of the composite material portion and the second region of the top surface of the base materiel,
the second region of the top surface of the base material is set to be lower than the top surface of the composite material portion by a height difference in a height direction that is perpendicular to a radial direction of the piston;
the height difference is determined based on a difference in anodization rate of the anodized aluminum coating on the top surface of the composite material portion and the second region of the top surface of the base material; and
a first thickness of the anodized aluminum coating formed on the top surface of the composite material portion is smaller than a second thickness of the anodized aluminum coating formed on the second region of the top surface of the base material by the height difference.

7. The internal-combustion-engine piston according to claim 6 ,
wherein the height direction is perpendicular to the top surface of the composite material portion and the seco

Assignees

• Isuzu Motors Ltd

Inventors

• Iizuka Tateoki

Classifications

• F02F3/12

  on piston heads · CPC title

• F05C2253/12

  Coating · CPC title

• F02F3/14 Primary

  within combustion chambers · CPC title

• B22D19/0027

  pistons · CPC title

• F02F2200/06

  Casting · CPC title