U.S. patent application number 10/846583 was filed with the patent office on 2005-07-21 for connecting rod and method for manufacturing the same.
This patent application is currently assigned to Gehring GmbH & Co. KG. Invention is credited to Abeln, Tobias, Klink, Ulrich.
Application Number | 20050155451 10/846583 |
Document ID | / |
Family ID | 32116276 |
Filed Date | 2005-07-21 |
United States Patent
Application |
20050155451 |
Kind Code |
A1 |
Abeln, Tobias ; et
al. |
July 21, 2005 |
Connecting rod and method for manufacturing the same
Abstract
A connecting rod (1) has a small connecting rod eye (2) and a
large connecting rod eye (3). A bearing shell (4, 5) is disposed in
at least one connecting rod eye (2, 3), wherein the bearing shell
(4, 5) is held in the connecting rod eye (2, 3) for secure mutual
rotation therewith. To obtain good adhesion of the bearing shell
(4, 5) in the connecting rod eye (2, 3), the bore surface (12, 13)
in one connecting rod eye (2, 3) and/or the outer surface of a
bearing shell (4, 5) has/have a structure (6, 7, 24, 26, 28, 30,
32, 34, 37, 38), wherein the structure (6, 7, 24, 26, 28, 30, 32,
34, 37, 38) is formed by elevations (9), the elevations (9)
delimiting the outer periphery of depressions (8). In a method for
producing a connecting rod (1) comprising at least one connecting
rod eye (2, 3) with a structured surface (12, 13), wherein a
bearing shell (4, 5) is disposed in the connecting rod eye (2, 3)
after structuring of the surface, the surface (12, 13) is
structured with a laser.
Inventors: |
Abeln, Tobias; (Stuttgart,
DE) ; Klink, Ulrich; (Neuffen, DE) |
Correspondence
Address: |
Dreiss, Fuhlendorf, Steimle & Becker
Patentanwalte
Postfach 10 37 62
Stuttgart
D-70032
DE
|
Assignee: |
Gehring GmbH & Co. KG
Ostfildern
DE
|
Family ID: |
32116276 |
Appl. No.: |
10/846583 |
Filed: |
May 17, 2004 |
Current U.S.
Class: |
74/579R |
Current CPC
Class: |
F16C 9/04 20130101; Y10T
74/2142 20150115; F16C 33/08 20130101; F16C 2226/50 20130101; F16C
2360/22 20130101; F16C 33/1065 20130101; F16C 33/103 20130101; F16C
2226/10 20130101; F16C 35/02 20130101 |
Class at
Publication: |
074/579.00R |
International
Class: |
F01B 031/10 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2002 |
EP |
02 025 788.7 |
Claims
We claim:
1. A connecting rod comprising: a first end having a small
connecting rod eye; a second end cooperating with and spaced apart
from said first end, said second end having a large connecting rod
eye; and at least one bearing shell disposed in said small and/or
said large connecting rod eye for secure mutual rotation therewith,
wherein at least one of an inner surface of said small and/or said
large connecting rod eye and an outer surface of said at least one
bearing shell has a structure, said structure having elevations
adjacent to and delimiting depressions.
2. The connecting rod of claim 1, wherein said depressions are
formed as furrows.
3. The connecting rod of claim 2, wherein said furrows are disposed
in straight lines.
4. The connecting rod of claim 2, wherein said furrows are disposed
to cross.
5. The connecting rod of claim 2, wherein said furrows are
wavy.
6. The connecting rod of claim 1, wherein said depressions are
formed as closed pockets.
7. The connecting rod of claim 6, wherein, as viewed from above,
said pockets have an elongated or round shape.
8. The connecting rod of claim 1, wherein an inner surface of said
bearing shell and/or an outer surface of a component disposed in
said bearing shell has a structure which is only formed from
depressions.
9. A method for producing a connecting rod, the connecting rod
having a first end defining a small connecting rod eye, a second
end cooperating with and spaced apart from said first end, said
second end defining a large connecting rod eye, and at least one
bearing shell disposed in said small and/or said large connecting
rod eye for secure mutual rotation therewith, the method comprising
the step of: structuring at least one of an inner surface of said
small and/or said large connecting rod eye and an outer surface of
said at least one bearing shell, said structuring having elevations
adjacent to and delimiting depressions.
10. The method of claim 9, wherein said inner surface is structured
by a laser.
Description
[0001] This application is related to EP 02 025 788.7 filed Nov.
16, 2002, the entire disclosure of which is hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] The invention concerns a connecting rod and a method for
producing a connecting rod in accordance with the independent
claims.
[0003] The book "Jahrbuch Schleifen, Honen, Lppen und Polieren"
(annual grinding, honing, lapping and polishing) by H.-W.
Hoffmeister and H.-K. Tonshoff (publisher), Vulkan-Verlag Essen,
2002, pages 396 to 408 discloses a holding groove on a connecting
rod eye into which a nose, formed on the bearing shell, projects.
The surface of the connecting rod eye is conventionally honed to
improve the tight fit of the bearing shell.
[0004] It is the underlying purpose of the invention to produce a
connecting rod of this type, which provides sufficient fixation of
the bearing shell in the connecting rod eye even under high loads,
and to propose a method for producing a connecting rod having a
long service life.
SUMMARY OF THE INVENTION
[0005] This object is achieved with a connecting rod having the
features of the independent claims.
[0006] Good fixation of a bearing shell in a connecting rod eye is
ensured by providing a surface structure in a connecting rod eye
with depressions whose outer periphery is delimited by elevations.
The elevations on the structured edges of the structure anchor the
bearing shell in the connecting rod eye. The structure may be a
uniform pattern which can be adapted to the loads which occur and
which can be reproduced during manufacture. The structure can be
adapted to working loads in a simple manner by changing the depth
of the depressions and the height of the elevations.
[0007] The depressions with sideward elevations are suitably
designed as furrows. The furrows may advantageously be straight or
cross each other. The furrows may also be wavy. The depressions may
advantageously be formed as closed pockets. As viewed from above,
the pockets may advantageously have an elongated or round shape.
The inner surface of a bearing shell and/or the surface of a
component disposed in the bearing shell advantageously has/have a
structure which is formed from depressions only. The depressions
act as micro-pressure chambers which facilitate hydraulic
lubrication to reduce friction between the sliding partners.
[0008] The production of the connecting rod can be facilitated by
structuring the surface of a connecting rod eye using a laser. The
laser structuring simultaneously permits good adaptation of the
structure to the working loads. The elevations are formed by
displaced melt produced during processing at the structure edges,
which is generated through thermal processing. The height of the
elevations can be adjusted via the displaced melt volume. The melt
volume can be varied by the processing parameters, i.e., for
example, via the advance speed or via the laser parameters, i.e.,
for example, through adjustment of the power or the pulse duration.
Laser processing facilitates changes to the design of the
structure, such as the surface portion of pocket structures or the
angles of intersection of crossing structures. The height and the
width of the elevations influence the adhesion of the bearing shell
in the connecting rod eye and can also be easily varied during
laser processing.
[0009] Embodiments of the invention are explained below with
reference to the drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0010] FIG. 1 shows a schematic perspective view of a connecting
rod;
[0011] FIG. 2 shows a section through a large connecting rod eye
with bearing shell disposed therein, and a crankshaft;
[0012] FIG. 3 shows the profile of a surface of a connecting rod
eye along the line III-III in FIG. 4;
[0013] FIG. 4 shows a top view onto a section of a surface of a
connecting rod eye;
[0014] FIG. 5 shows the profile of the surface of a connecting rod
eye along the line V-V in FIG. 6;
[0015] FIG. 6 shows a section of a top view onto the surface of a
connecting rod eye;
[0016] FIGS. 7 shows a schematic view from above of first surface
structures;
[0017] FIGS. 8 shows a schematic view from above of second surface
structures;
[0018] FIGS. 9 shows a schematic view from above of third surface
structures;
[0019] FIGS. 10 shows a schematic view from above of fourth surface
structures;
[0020] FIGS. 11 shows a schematic view from above of fifth surface
structures; and
[0021] FIGS. 12 shows a schematic view from above of sixth surface
structures.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] The connecting rod 1, schematically shown in FIG. 1, has a
small connecting rod eye 2 and a large connecting rod eye 3. For
use in a combustion engine, a piston pin is conventionally disposed
in the small connecting rod eye 2 and the crankshaft is disposed in
the large connecting rod eye 3. A bearing shell 4 is disposed in
the small connecting rod eye 2, and a bearing shell 5 is disposed
in the large connecting rod eye 3. To rigidly fix the bearing
shells 4, 5 in the connecting rod eyes 2, 3, the bore surfaces 12
and 13 of the connecting rod eyes 2 and 3 have structures 6 and 7.
The structures 6 and 7 increase the adhesion of the bearing shells
4 and 5. Instead of or in addition to the structures 6, 7 of the
bore surfaces 12, 13, the outer surfaces of the bearing shells 4, 5
which are in contact with the bore surfaces 12, 13 may have
corresponding structures. The friction between the inner side of
the bearing shells 4 and 5 and the piston pin or the crankshaft
should be minimized. To reduce friction, the inner surface 21 of
the bearing shell 4 has a structure 22 and the inner surface 18 of
the bearing shell 5 has a structure 20.
[0023] To fix a bearing shell 4, 5 in a connecting rod eye 2, 3, a
nose 15 may be disposed on the outer periphery of a bearing shell,
in addition to the structure 6, 7, as exemplarily shown in the
bearing shell 5 of FIG. 2. The nose 15 extends radially outwardly
at the outer periphery of the bearing shell 5. In the region of the
nose 15, the connecting rod eye 3 of the connecting rod 1 has a
holding groove 14 into which the nose 15 projects. The surface 13
of the connecting rod eye 3 additionally has a structure (not shown
in FIG. 2). The crankshaft 16 is disposed in the bearing shell 5
and rotates in the direction of the arrow 17. While the friction
between bearing shell 5 and connecting rod eye 3 should be as large
as possible to rigidly hold the bearing shell 5 in the connecting
rod eye 3, the friction between the bearing shell 5 and the
crankshaft 16 should be as small as possible. Towards this end, the
inner surface 18 of the bearing shell 5 has a structure 20 (shown
in FIG. 1). A structure corresponding to the structure 20 may be
provided on the outer surface 19 of the crankshaft 16 rather than
on the inner surface 18.
[0024] FIGS. 3 and 4 show, in an enlarged scale, a structure 37 of
a surface 39 which may be the surface 12, 13 of a connecting rod
eye 2, 3. The structure 37 may be provided in the small connecting
rod eye 2 and/or in the large connecting rod eye 3. The structure
37 is introduced into the surface 39 which has a basic structure
23. The structure 37 is advantageously produced with a laser. The
basic structure 23 may e.g. be a cross structure produced through
honing. The basic structure 23 may also consist of peripheral
furrows produced during spindling of the surface 39. Elongated
pockets 11 are introduced into the basic structure 23 at regular
intervals which are formed by a depression 8 whose periphery is
delimited by a circumferential elevation 9. The depressions 8 have
a depth a relative to the surface 39 while the elevations 9 extend
beyond the surface 39 by a height b. The elevations 9 have a width
c and the depressions 8 have a width d. The depth a and the height
b advantageously are approximately up to 50 .mu.m. The width c, d
is advantageously selected to be .ltoreq.50 .mu.m.
[0025] FIGS. 5 and 6 show an embodiment of a structure 38 of the
large connecting rod eye 3 which may be introduced into the surface
12, 13 of the connecting rod eye 2, 3 and is formed by round
pockets 10. The round pockets 10 are suitably uniformly introduced
into the surface 40. The round pockets 10 have a circular
depression 8 whose outer periphery is also surrounded by a circular
elevation 9. The round pockets 10 are also introduced into a
surface 40 having a basic structure 23.
[0026] FIGS. 7 through 12 show examples of an arrangement of a
structure on a surface. The double arrow 36 thereby designates the
peripheral direction of the connecting rod eye or of the bearing
shell. In the structure 24 shown in FIG. 7, the pockets 25 are
disposed in a regular pattern. The pockets 25 may have a depression
8 and an elevation 9, in correspondence with the round pockets 10
shown in FIGS. 5 and 6. The structure 24 is suitably introduced on
the bore surface 12 of the small connecting rod eye 2 or the bore
surface 13 of the large connecting rod eye 3. It may also be
appropriate to provide pockets 25 without elevations 9. Such
pockets reduce the friction between the sliding partners, since
they are used as a lubricant reservoir thereby permitting full
hydrodynamic lubrication. The pockets simultaneously act as
micro-pressure chambers. Pockets 25 of such a design are suitably
disposed on the inner surface 21 of the bearing shell 4 and/or on
the outer periphery of a piston pin and on the inner surface 18 of
the bearing shell 5 and/or the outer surface 19 of the crankshaft
16.
[0027] FIG. 8 shows elongated pockets 27 which extend approximately
in a peripheral direction. The elongated pockets 27 are disposed at
regular intervals and form a structure 26. The structure 28 of FIG.
9 is formed by elongated pockets 29 which extend approximately
transversely to the peripheral direction. It may also be suitable
to provide elongated pockets which subtend an angle of between
0.degree. and 90.degree. with respect to the peripheral direction.
The structures 26 and 28 may be disposed on the inner surface 18 of
the bearing shell 5 or the outer surface 19 of the crankshaft 16
and/or the inner surface 21 of the bearing shell 4 or the outer
surface of a piston pin. The pockets 27 and 29 are thereby suitably
formed only as depressions. The pockets 27 and 29 may each be
delimited at their outer periphery by an elevation 9. Pockets 27
and 29 of this design increase friction and are preferably disposed
on the surface 12 of the connecting rod eye 2 or the surface 13 of
the connecting rod eye 3.
[0028] The structure 30 of FIG. 10 is formed by crossing furrows 31
which are each delimited by elevations 9. The furrows 31 have an
angle of intersection a. The structure 30 is suitably formed on a
surface 12, 13 of a connecting rod eye 2, 3. The adhesion of the
structure 30 may be influenced by varying the angle of intersection
.alpha.. FIG. 11 shows a structure 32 having wavy furrows 33. The
outer periphery of the furrows 33 also comprises elevations 9. The
furrows 33 are suitably disposed on the surfaces 12 and 13 of the
connecting rod eyes 2 and 3. FIG. 12 shows a structure 34 with
furrows 35 which extend parallel to each other. The furrows 35 are
disposed approximately perpendicularly to the peripheral direction
in FIG. 12. The furrows 35 may suitably subtend an angle of less
than 90.degree. with respect to the peripheral direction. The
furrows 35 may also have elevations 9 at their outer periphery to
increase the friction between connecting rod eye 2, 3 and bearing
shell 4, 5.
[0029] A connecting rod 1 is advantageously produced by structuring
the surface 12, 13 of one or both connecting rod eyes 2, 3 using a
laser. The surface 12, 13 is advantageously fine machined before
laser structuring thereby producing a basic structure 23 into which
the structure is introduced. For pocket structures 10, 11, 24, 26,
28, the adhesion of a structure 6, 7 on the surface 12, 13 of a
connecting rod eye 2, 3 may be greatly influenced by the surface
portion. For cross structures 30, the adhesion can be changed by
varying the angle of intersection .alpha.. The height b of the
elevations 9 and the width of the elevations 9 have an influence on
the adhesion of all structures.
* * * * *