Machining process for trapezoid rings with small axial dimensions, used in pistons of internal combustion engines

Patent metadata

Field	Value
Publication number	US-10197161-B2
Application number	US-201414782109-A
Country	US
Kind code	B2
Filing date	Feb 28, 2014
Priority date	Apr 3, 2013
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A method for producing a piston for internal combustion engines, where the piston includes a circumferential trapezoid annular groove for receiving trapezoid rings with small axial dimensions the groove having a groove base with adjoining surfaces and groove flanks. The groove base with adjoining surfaces is created in a first method step by machining using a cutting steel tool and the groove flanks are created in a further method step. Also disclosed are a piston produced according to the method and a cutting steel tool.

First claim

What is claimed is:

1. A method for producing a piston for internal combustion engines comprising:
machining in a first step a trapezoidal circumferential annular ring groove in a piston blank operable to receive trapezoidal-shaped rings, the first machining step further comprising:
plunge cutting a groove base with a tool steel, the groove base having ends defining a height h 4 greater than zero (0) millimeters and less than one (1) millimeter (mm);
plunge cutting two flanks in the piston blank with the tool steel, each flank connected to a respective one of the base ends and extending radially and horizontally outward from a piston stroke axis, the two flanks oriented parallel to one another;
plunge cutting two groove flanks in the piston blank with the tool steel, each groove flank connected to a respective one of the flanks and extending radially and angularly outward from the piston stroke axis; and
machining in a second step the trapezoidal ring groove in the piston blank, the second machining step comprising finish machining the two groove flanks.

2. The method of claim 1 wherein the second machining step comprises finish machining of only the two groove flanks without further machining of the two flanks or the groove base.

3. A method for producing a piston for internal combustion engines comprising:
machining in a first step a trapezoidal circumferential annular ring groove in a piston blank operable to receive trapezoidal-shaped rings, the first machining step further comprising:
plunge cutting a groove base having ends defining a height h 4 greater than zero (0) millimeters and less than one (1) millimeter (mm);
plunge cutting a radius R 2 of 0.2 millimeters (mm) at each groove base end;
plunge cutting two flanks in the piston blank, each flank connected to a respective one of the base ends and extending radially and horizontally outward from a piston stroke axis, the two flanks oriented parallel to one another;
plunge cutting two groove flanks at an angle alpha (α) of 15 degrees and 12 minutes relative to one another in the piston blank, each groove flank connected to a respective one of the flanks and extending radially and angularly outward from the piston stroke axis; and
machining in a second step the trapezoidal ring groove in the piston blank, the second machining step comprising finish machining the two groove flanks.

Assignees

• Ks Kolbenschmidt Gmbh

Inventors

• Friede Reiner
• Beller Denis

Classifications

• B23B2200/0485

  Trapezium · CPC title

• F16J9/203

  Oil-scraping rings · CPC title

• B23B2215/245

  Pistons · CPC title

• F16J9/20 Primary

  Rings with special cross-section (L-section rings F16J9/02); Oil-scraping rings {(F16J9/06 takes precedence)} · CPC title

• B23B2215/247

  Piston rings · CPC title