CONNECTING ROD

Abstract

A connecting rod for an internal combustion engine may include a big end passage for receiving a pin journal of a crankshaft, a small end passage for receiving a piston pin, and a beam extending between the big and small end passages. The small end passage may extend along a passage axis and be delimited by opposed edges. The small end passage may include an inner passage surface with a cylindrical surface portion having a first diameter. The small end passage may extend along the passage axis between the opposed edges. The inner passage surface may comprise profiled regions adjacent to the opposed edges and extending at least over a part of a circumference of the opposed edges. The profiled regions may begin from the cylindrical surface portion and increase into a maximum second diameter at the opposed edges. Further, a plurality of dimples may be positioned along the cylindrical surface portion of the inner passage surface.

Claims

1.-9. (canceled)

10. A connecting rod for an internal combustion engine, the connecting rod comprising: a big end passage configured to receive a pin journal of a crankshaft; a small end passage configured to receive a piston pin, the small end passage extending along a passage axis and delimited by opposed edges, wherein the small end passage comprises an inner passage surface with a cylindrical surface portion that has a first diameter and a plurality of dimples, wherein the inner passage surface comprises profiled regions that are adjacent to the opposed edges and extend at least over a part of a circumference of the opposed edges, with the profiled regions beginning at the cylindrical surface portion and increasing to a maximum second diameter at the opposed edges; and a beam disposed between the big end passage and the small end passage.

11. The connecting rod of claim 10 wherein the profiled regions are configured in a shape of a trumpet or in a shape of a multiple-chamfer.

12. The connecting rod of claim 10 wherein the profiled regions comprise a single chamfer, wherein an angle between a surface of the chamfer and the passage axis is between 1 arcminute and 1 degree.

13. The connecting rod of claim 10 wherein the profiled regions comprise a single chamfer, wherein an angle between a surface of the chamfer and the passage axis is between 5 to 25 arcminutes.

14. The connecting rod of claim 10 wherein the profiled regions have a width as measured along the passage axis in a range of 4 mm to 15 mm.

15. The connecting rod of claim 10 wherein the profiled regions form a crescent shape through the passage axis over a circumferential angle through which the profiled regions extend along the part of the circumference of the opposed edges.

16. The connecting rod of claim 15 wherein the profiled regions are positioned in or next to a section of the small end passage where the beam transitions into the small end passage.

17. The connecting rod of claim 10 wherein the plurality of dimples have a diameter of 50 μm to 110 μm.

18. The connecting rod of claim 10 wherein the plurality of dimples have a depth of 5 μm to 6 μm.

19. The connecting rod of claim 10 wherein the plurality of dimples is disposed in a defined region of the inner passage surface, wherein the plurality of dimples occupies a cumulated surface area of 4% to 11% of the defined region.

20. The connecting rod of claim 10 wherein the plurality of dimples is disposed in a defined region of the inner passage surface, wherein the defined region is positioned between the profiled regions.

21. The connecting rod of claim 10 wherein the plurality of dimples is disposed in a defined region of the inner passage surface, wherein the defined region is positioned adjacent to at least one of the profiled regions within the small end passage.

Description

PREFERRED EMBODIMENT OF THE INVENTION

[0031] Additional details, characteristics and advantages of the object of the invention are disclosed in the subclaims and the following description of the respective figures, which show a preferred embodiment in an exemplary fashion of the subject matter according to the invention in conjunction with the accompanying figures, in which shows

[0032] FIG. 1 a cross section side view of a connecting rod,

[0033] FIG. 2 a lateral view of the small end and the shaft of the connecting rod according to FIG. 1,

[0034] FIG. 3 the small end of the connecting rod with the surface in the small end passage,

[0035] FIG. 4 an unwind small end surface with a profiled regions and with a defined region comprising dimples,

[0036] FIG. 5 a special pattern of dimples within the surface of the small end passage,

[0037] FIG. 6 different shaped dimples,

[0038] FIG. 7a a profiled region with a trumpet shape,

[0039] FIG. 7b a profiled region with a single-chamfer shape and

[0040] FIG. 7c a profiled region with a multiple-chamfer shape.

[0041] FIG. 1 shows a connecting rod 1 for an internal combustion engine having a big end passage 10, which is performed to receive a pin journal of a crank shaft of the engine, and the connecting rod 1 comprises a small end passage 11, which is performed for receiving a piston pin of a piston, and between the big end passage 10 and the small end passage 11 a shaft 12 is arranged, and the shaft 12 forms a connection between the big end passage 10 and the small end passage 11. The connecting rod 1 according to the invention is designed in a single-piece construction, excluding a big end comprising two pieces, e.g. comprising a stem and cap arrangement.

[0042] The small end passage 11 features an inner passage surface 13, which transits into the side walls 23 of the small end with opening edges 15. Accordingly, the length of the small end passage 11 is defined by the length of the passage 11 along the passage axis 14 from side wall 23 to side wall 23, and from opening edge 15 to opening edge 15, respectively.

[0043] FIG. 2 shows the connecting rod 1 in a lateral view with the shaft 12 and the small end passage 11 featuring the inner passage surface 13, and the lateral view axis lies in the passage axis 14. Accordingly, one of the side walls 23 is shown and surrounds the small end passage 11. The diameter D defines the passage diameter for receiving a piston pin.

[0044] FIG. 3 shows a perspective view of the small end of the connecting rod 1 with the small end passage 11 extending along the passage axis 14. The depiction shows the inner passage surface 13 with profiled regions 16 adjacent to the opening edge 15 and with a defined region 17 in which dimples 18 are arranged. The defined region 17 comprising dimples 18 and the profiled region 16 adjacent to the front opening edge 15 are separated from each other, and the region 17 is neighboring the region 16.

[0045] The profiled regions 16 each form a crescent shape around the passage axis 14, and in the depiction is pointed out a force center F, which identifies a maximum load of the small end of the connecting rod 1 in an exemplary fashion. In the circumferential region of the force center F the defined region 17 comprising dimples 18 is located, and the crescent shape of the profiled regions 16 form a maximum width 21. In this profiled regions 16 the diameter D of the passage 11 is minimal increased and is shown with the diameter D′.

[0046] When the connecting rod 1 is applied in an internal combustion engine, and the piston pin deviates from a cylindrical shape due to combustion forces, the direction and the amount of the piston pin deviation corresponds to the position and the shape of the crescent shape forming the profiled regions 16. The maximum deviation conforms to the force center F and thus conforms to the maximum crescent width 21. Moreover, the density of dimples 18 within the defined region 17 features a maximum in the force center F.

[0047] FIG. 4 shows another embodiment of the small end passage, and the inner passage surface 13 is shown in an unwind manner. In the surface 13 the defined region 17 with dimples 18 is shown in between the profiled regions 16, which are located adjacent to each of the opposing opening edges 15.

[0048] FIG. 5 shows another embodiment of the inner passage surface 13 with a plurality of dimples 18, which are oriented in single rows 24 under an angle □ relative to the passage axis 14. This leads to a special pattern of dimples 18 for improving the lubrication of the cylindrical section in the small end passage 11.

[0049] In FIG. 6 different shapes of dimples 18 are shown, and the orientation of the dimple shape is defined by the orientation of the rows 24. Three different shapes of dimples 18 are shown in an exemplary fashion, and the first dimple 18 features a circular shape, the second dimple 18 shows a triangular shape and the third dimple 18 shows an elliptic shape. The triangular shape and the elliptic shape are oriented relative to the row 24 as depicted.

[0050] FIG. 7a shows a first embodiment of a profiled region 16 with a trumpet shape 19, which forms the transition between the inner passage surface 13 into the side wall 23 in the opening edge 15.

[0051] FIG. 7b shows another embodiment of a profiled region 16 with a single chamfer shape 22, which forms the transition between the inner passage surface 13 into the side wall 23 in the opening edge 15. The chamfer 22 features an angle □, which can feature—not shown in true scale.

[0052] FIG. 7c shows another embodiment of a profiled region 16 with a plurality of chamfers forming a multiple chamfer shape 20 between the inner passage surface 13 and the side wall 23 in the opening edge 15 of the small end passage of a connecting rod. This multiple-chamfer shape 20 leads to a polygon transition in the opening edge 15.

[0053] The present invention is not limited by the embodiment described above, which is represented as an example only and can be modified in various ways within the scope of protection defined by the appending patent claims.

LIST OF NUMERALS

[0054] 1 connecting rod [0055] 10 big end passage [0056] 11 small end passage [0057] 12 beam [0058] 13 inner passage surface [0059] 14 passage axis [0060] 15 opening edge [0061] 16 profiled region [0062] 17 defined region [0063] 18 dimple [0064] 19 trumpet shape [0065] 20 multiple—chamfer shape [0066] 21 width [0067] 22 chamfer [0068] 23 side wall [0069] 24 row [0070] F force centre [0071] D diameter before chamfer [0072] D′ diameter at chamfer edge [0073] □ circumferential angle [0074] □ angle of dimples distribution [0075] □ angle of chamfer [0076] d diameter [0077] h depth [0078] v volume