Applicant claims priority under 35 U.S.C. §119 of German Application No. 10 2004 057 559.2 filed Nov. 30, 2004. Applicant also claims priority under 35 U.S.C. §365 of PCT/DE2005/002140 filed Nov. 28, 2005. The international application under PCT article 21(2) was not published in English.
The invention relates to a piston for an internal combustion engine, in accordance with the preamble of claim 1.
A piston for an internal combustion engine is known from the patent DD 123 962; it consists of a piston base body and a ring-shaped groove reinforcement screwed onto the piston base body in the region of the piston crown. In this connection, the groove reinforcement encloses a recess formed into the piston base body, and thereby creates a ring-shaped, closed cooling channel. On the side of the piston base body, there is the thread onto which the groove reinforcement is screwed on, on the radial outside of a collar formed onto the outside of the piston close to the piston crown, which collar, however, has a radial dimension that is so short that it has no elastic resilience of any kind. This brings with it the disadvantage that no bias that strengthens the screw connection can be exerted onto this connection.
It is the task of the invention to avoid this disadvantage of the state of the art.
This task is accomplished with the characteristics standing in the characterizing part of the main claim. Practical embodiments of the invention are the object of the dependent claims.
An exemplary embodiment of the invention will be described below, using the drawings. These show:
The piston base body 2 has two pin bosses 5 and 6 on the underside facing away from the piston crown 3, in which there is a pin bore 7 and 8 for accommodating a piston pin, not shown in the figures, in each instance. As particularly shown in
The piston crown 3 has a combustion bowl 11 configured in flat manner. A circumferential collar 12 that is at least approximately rectangular in cross-section and points radially outward is formed onto the radial outside of the piston 1 in the region on the piston crown side, which collar carries a circumferential thread 13 radially on the outside, and is followed by a circumferential recess 14 on the pin boss side. On the pin boss side, the recess 14 is followed by a circumferential projection 15 that points radially outward, into which projection part of the recess 14 is formed on the piston crown side, which part carries the lower part of the ring belt 16 radially on the outside, and which part has a cooling channel 17, which is open in the direction of the pin bosses 5, 6, on the pin boss side.
As also shown in
Furthermore, the groove reinforcement 4 screwed onto the piston 1 closes off the recess 14 and thereby forms a closed cooling channel 21, which is connected with the interior region of the piston 1 by way of inflow and outflow openings 30, 33, which will be explained in greater detail below.
Radially on the outside, a compression ring groove 22 is formed into the groove reinforcement 4. On the pin boss side, the groove reinforcement 4 has a level, ring-shaped contact surface 23, which makes contact with a ring-shaped contact surface 24, shaped in similar manner, disposed on the projection 15 on the piston crown side, when the groove reinforcement 4 is screwed onto the piston 1.
The piston base body 2 consists of an aluminum/silicon alloy having a maximal silicon content of 15%, whereby the piston base body 2 is produced using a forging method or a casting method. The groove reinforcement 4 consists of an aluminum alloy that contains 15% to 26% silicon in order to increase its friction-wear resistance, and 2.5% to 7% copper in order to increase its resistance to deformations during engine operation. A further increase in the friction-wear resistance of the groove reinforcement 4 can be achieved if silicon carbide particles are mixed into the alloy. The groove reinforcement 4 is produced using a casting method, after which the groove reinforcement 4 is post-compressed in order to reduce its porosity and thereby optimize its mechanical properties, by way of the method of hot isostatic pressing (HIP).
A ring-shaped sealing element 27 of, spring steel is disposed between the projection 20 of the groove reinforcement 4 that lies radially on the inside and the collar 12, which element seals off the cooling channel 21 from combustion gases that act on the piston crown 1, and has the shape of a plate edge. In
Number | Date | Country | Kind |
---|---|---|---|
10 2004 057 559 | Nov 2004 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/DE2005/002140 | 11/28/2005 | WO | 00 | 7/10/2007 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2006/058521 | 6/8/2006 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
4375782 | Schieber | Mar 1983 | A |
4488522 | Jones | Dec 1984 | A |
6003479 | Evans | Dec 1999 | A |
7308850 | Scharp | Dec 2007 | B2 |
20060243131 | Scharp | Nov 2006 | A1 |
Number | Date | Country |
---|---|---|
722 1644 | Aug 1972 | DE |
123 962 | Jan 1977 | DE |
27 36 815 | Mar 1978 | DE |
29 14 456 | Oct 1980 | DE |
29 16 441 | Nov 1980 | DE |
32 31 998 | Mar 1983 | DE |
37 19 469 | Dec 1988 | DE |
103 49 291 | Apr 2005 | DE |
0 178 747 | Apr 1986 | EP |
Number | Date | Country | |
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20080134876 A1 | Jun 2008 | US |