Connecting rod and method for manufacturing the same
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.
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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 INVENTIONThe invention concerns a connecting rod and a method for producing a connecting rod in accordance with the independent claims.
The book “Jahrbuch Schleifen, Honen, Läppen und Polieren” (annual grinding, honing, lapping and polishing) by H.-W. Hoffmeister and H.-K. Tönshoff (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.
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 INVENTIONThis object is achieved with a connecting rod having the features of the independent claims.
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.
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.
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.
Embodiments of the invention are explained below with reference to the drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIGS. 7 shows a schematic view from above of first surface structures;
FIGS. 8 shows a schematic view from above of second surface structures;
FIGS. 9 shows a schematic view from above of third surface structures;
FIGS. 10 shows a schematic view from above of fourth surface structures;
FIGS. 11 shows a schematic view from above of fifth surface structures; and
FIGS. 12 shows a schematic view from above of sixth surface structures.
DESCRIPTION OF THE PREFERRED EMBODIMENT The connecting rod 1, schematically shown in
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
The structure 30 of
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 α. The height b of the elevations 9 and the width of the elevations 9 have an influence on the adhesion of all structures.
Claims
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.
Type: Application
Filed: May 17, 2004
Publication Date: Jul 21, 2005
Applicant: Gehring GmbH & Co. KG (Ostfildern)
Inventors: Tobias Abeln (Stuttgart), Ulrich Klink (Neuffen)
Application Number: 10/846,583