U.S. patent application number 13/516797 was filed with the patent office on 2013-01-03 for method for producing a piston for an internal combustion engine and piston that can be produced by means of said method.
This patent application is currently assigned to MAHLE INTERNATIONAL GMBH. Invention is credited to Klaus Keller.
Application Number | 20130000590 13/516797 |
Document ID | / |
Family ID | 43768733 |
Filed Date | 2013-01-03 |
United States Patent
Application |
20130000590 |
Kind Code |
A1 |
Keller; Klaus |
January 3, 2013 |
METHOD FOR PRODUCING A PISTON FOR AN INTERNAL COMBUSTION ENGINE AND
PISTON THAT CAN BE PRODUCED BY MEANS OF SAID METHOD
Abstract
The present invention relates to a method for producing a piston
(10) from an upper piston part (11, 111, 211) and a lower piston
part (15). A strip- or plate-shaped semifinished product (22) made
of a metal material is provided, from which an annular upper piston
part (11, 111, 211) or an annular blank (25) is stamped out, which
blank is finished to form an upper piston part (11, 111, 211),
wherein the upper piston part (11, 111, 211) is connected to a
lower piston part (15) to form a piston (10).
Inventors: |
Keller; Klaus; (Lorch,
DE) |
Assignee: |
MAHLE INTERNATIONAL GMBH
Stuttgart
DE
|
Family ID: |
43768733 |
Appl. No.: |
13/516797 |
Filed: |
December 17, 2010 |
PCT Filed: |
December 17, 2010 |
PCT NO: |
PCT/DE2010/001483 |
371 Date: |
September 12, 2012 |
Current U.S.
Class: |
123/193.1 ;
29/888.04 |
Current CPC
Class: |
F02F 3/0092 20130101;
Y10T 29/49249 20150115; B21K 1/185 20130101; B21K 1/18 20130101;
B23P 15/10 20130101; F02F 3/003 20130101; Y10T 29/49252 20150115;
Y10T 29/49256 20150115 |
Class at
Publication: |
123/193.1 ;
29/888.04 |
International
Class: |
B23P 15/10 20060101
B23P015/10; F02F 3/00 20060101 F02F003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 19, 2009 |
DE |
10 2009 059 658.5 |
Claims
1. Method for the production of a piston (10) for an internal
combustion engine, comprising the following method steps: (a)
making available a strip-shaped or plate-shaped semi-finished
product (22) made of a metallic material, (b) punching a
ring-shaped blank (25) out of the semi-finished product 22, (c)
finishing the blank (25) to produce an upper piston part (11, 111,
211), (d) connecting the upper piston part (11, 111, 211) to a
lower piston part (15), to produce a piston (10).
2. Method for the production of a piston (10) for an internal
combustion engine, comprising the following method steps: (a)
making available a strip-shaped or plate-shaped semi-finished
product (22) made of a metallic material, (b) finishing at least
one surface (26) of the strip-shaped or plate-shaped semi-finished
product (22), (c) punching a ring-shaped upper piston part (11,
111, 211) out of the semi-finished product (22), (d) connecting the
upper piston part (11, 111, 211) to a lower piston part (15), to
produce a piston (10).
3. Method according to claim 1, wherein a semi-finished product
(22) made from a steel material is used.
4. Method according to claim 3, wherein a semi-finished product
(22) made from a hot-rolled or cold-rolled steel material is
used.
5. Method according to claim 1, wherein the blank (25) is machined
level along at least one surface in step (c).
6. Method according to claim 2, wherein at least one surface (26)
of the semi-finished product (22) is machined level in step
(b).
7. Method according to claim 2, wherein after step (c), the upper
piston part (11, 111, 211) is finished.
8. Method according to claim 1, wherein a semi-finished product
(22) having a thickness of up to 15 mm is used.
9. Method according to claim 1, wherein during punching, a
circumferential lower recess (127, 227) is machined into the blank
(25) or into the upper piston part (11, 111, 211).
10. Method according to claim 1, wherein during punching, a least
one circumferential lateral recess (228) is machined into the blank
(25) or into the upper piston part (11, 111, 211).
11. Method according to claim 10, wherein the at least one
circumferential lateral recess (228) is formed on the outer or
inner circumference of the blank (25) or of the upper piston part
(11, 111, 211).
12. Method according to claim 1, wherein the upper piston part (11,
111, 211) and the lower piston part (15) are connected with one
another by means of welding or soldering.
13. Piston (10) for an internal combustion engine, which can be
produced by means of a method according to claim 1.
Description
[0001] The present invention relates to a method for the production
of a piston for an internal combustion engine, as well as to a
piston that can be produced by means of this method.
[0002] DE 103 11 149 A1 discloses a piston composed of an upper
piston part and a lower piston part, which are fixed in place by
means of a minimal number of weld points and are connected with one
another by means of subsequent forging. Such pistons are
characterized in that the upper piston part is produced from a
particularly temperature-resistant and high-strength material, in
order to prevent scaling, particularly in the region of the
combustion bowl. However, production of such a piston is
complicated and connected with significant costs.
[0003] The task of the present invention consists in making
available a method for the production of a piston for an internal
combustion engine, which method can be implemented with the least
possible effort and reduced costs.
[0004] A first solution, according to the invention, consists in
that a strip-shaped or plate-shaped semi-finished product made of a
metallic material is made available, that a ring-shaped blank is
punched out of the semi-finished product and subsequently finished
to produce an upper piston part, and that the finished upper piston
part is connected to a lower piston part, to produce a piston.
[0005] A second solution, according to the invention, consists in
that a strip-shaped or plate-shaped semi-finished product made of a
metallic material is made available, that at least one surface of
the strip-shaped or plate-shaped semi-finished product is finished,
that a ring-shaped upper piston part is punched out of the
semi-finished product and subsequently connected to a lower piston
part, to produce a piston.
[0006] A piston that can be produced with this method is
furthermore an object of the present invention.
[0007] The present invention is characterized in that a
particularly simple method for the production of a piston, which
method can be implemented with few production steps and is
therefore cost-advantageous, is made available. In particular, an
upper piston part can be made available, which can be obtained, in
particularly simple manner, from any desired material. In this way
it is possible, for example, to make available a piston having a
particularly high-strength and temperature-resistant upper piston
part, in simple and cost-advantageous manner.
[0008] Advantageous further developments are evident from the
dependent claims.
[0009] Preferably, a semi-finished product made from a steel
material is used, so that the finished piston meets the
requirements during engine operation in optimal manner. In
particular, a hot-rolled or cold-rolled steel material is
particularly well suited.
[0010] For the case that a blank is punched out of the
semi-finished product, this blank is preferably machined level
along at least one surface, for example by means of lathing or
grinding. The level machined surface then forms the piston crown in
the finished piston.
[0011] For the case that a finished upper piston part is punched
out of the semi-finished product, preferably at least one surface
of the semi-finished product is machined level before punching. The
level machined surface then forms the piston crown in the finished
piston. Of course, the upper piston part can be machined as needed
after punching.
[0012] Depending on the requirements in an individual case,
semi-finished products having a thickness of up to 15 mm can be
used.
[0013] A preferred further development consists in that during
punching, a circumferential lower recess is machined into the blank
or into the upper piston part, and/or at least one circumferential
lateral recess is machined into the blank or the upper piston part,
by means of corresponding shaping of the punching tool. In the
finished piston, the lower recess forms at least one part of a
cooling channel. An outer recess forms part of a ring groove, for
example. An inner recess can form part of a combustion bowl, for
example.
[0014] The finished upper piston part can be connected with a lower
piston part, to produce a finished piston, for example by means of
soldering or welding. Of course, the piston can also be finished
subsequently, as needed.
[0015] Exemplary embodiments of the present invention will be
explained in greater detail in the following, using the attached
drawings. These show, in a schematic representation, not true to
scale:
[0016] FIG. 1 an exemplary embodiment of a piston according to the
invention, in section;
[0017] FIG. 2 a top view of a strip-shaped semi-finished product
for use in the method according to the invention;
[0018] FIG. 3 another exemplary embodiment of an upper piston part
produced according to the method according to the invention, in
section;
[0019] FIG. 4 another exemplary embodiment of an upper piston part
produced according to the method according to the invention, in
section.
[0020] FIG. 1 shows an exemplary embodiment of a piston 10. Because
the invention can be used for all piston types and all piston
materials, only one piston type will be used as an example in the
following, to describe the present invention.
[0021] In the exemplary embodiment, the piston 10 is a two-part
welded box piston, the structure of which is known as such. The
piston 10 has an upper piston part 11 having a circumferential top
land 12. The upper piston part 11 forms a piston crown 11a as well
as part of a combustion bowl 13, and has a piston ring groove 14
below the top land 12. The piston 10 furthermore has a lower piston
part 15 having two piston ring grooves 16, 17 as well as pin bosses
18 that are set back relative to the piston ring grooves 14, 16,
17. The pin bosses 18 are provided with pin bores 19 for
accommodating a piston pin (now shown). The upper piston part 11
and the lower piston part 15 together form a circumferential
cooling channel 21.
[0022] FIG. 2 shows an exemplary embodiment of a semi-finished
product 22, here a strip-shaped semi-finished product, for use in
the method according to the invention. The semi-finished product 22
consists, for example, of a hot-rolled or cold-rolled steel
material of the type 42CrMo4, having a thickness of 10 mm. The
cutting lines along which a ring-shaped blank or a ring-shaped
upper piston part is punched out, according to the present
invention, are indicated with 23, 24.
[0023] For the case that the semi-finished product 22 is used
without further processing, a ring-shaped blank 25 is punched out.
The blank 25 is machined level along at least one surface, for
example by means of grinding or lathing. This surface forms the
piston crown 11a of the upper piston part 11 in the finished piston
10. Subsequently, the finished upper piston part 11 is connected to
a lower piston part 15, to form a piston 10, for example by means
of soldering or welding, such as friction welding, electrode
welding, or laser welding. Of course, the piston 10 can also be
finished subsequently, as needed.
[0024] However, the semi-finished product 22 can be processed
further before being punched, in that at least one of its surfaces
26 is machined level, for example by means of grinding or lathing.
Subsequently, a ring-shaped upper piston part 11 is punched out.
The level machined surface 26 forms forms the piston crown 11a of
the upper piston part 11 in the finished piston 10. Subsequently,
the finished upper piston part 11 is connected to a lower piston
part 15, to form a piston 10, as described above. FIG. 3 shows an
exemplary embodiment of a ring-shaped upper piston part 111 punched
out of a semi-finished product 22. The upper piston part 111 has a
circumferential lower recess 127 that forms part of a
circumferential cooling channel in the finished piston; see the
cooling channel 21 in FIG. 1. The recess 127 is formed in that the
punching tool is provided with a corresponding embossing shape, in
known manner. Therefore the recess 127 is formed at the same time
with the punching process. The central opening 113 of the
ring-shaped upper piston part 111 forms part of a combustion bowl
in the finished piston; see the combustion bowl 13 in FIG. 1. Of
course, the same holds true analogously also for production of a
blank from the semi-finished product 22.
[0025] FIG. 4 shows another exemplary embodiment of a ring-shaped
upper piston part 211 punched out of a semi-finished product 22.
The upper piston part 211 also has a circumferential lower recess
227 that forms part of a circumferential cooling channel in the
finished piston; see the cooling channel 21 in FIG. 1. The upper
piston part 211 furthermore has a circumferential outer recess 228
that forms part of a piston ring groove in the finished piston; see
the piston ring groove 14 in FIG. 1. The recesses 227 and 228 are
formed in that the punching tool is provided with corresponding
embossing shapes, in known manner. Therefore the recesses 227 and
228 are formed at the same time with the punching process. The
central opening 213 of the ring-shaped upper piston part 211 forms
part of a combustion bowl in the finished piston; see the
combustion bowl 13 in FIG. 1. Of course, the same holds true
analogously also for production of a blank from the semi-finished
product 22.
* * * * *