Connecting rod

Abstract

A connecting rod for converting a linear motion of a piston into a rotational motion of a crankshaft may include a small connecting eye for connecting the connecting rod in a rotatable manner to a pin of the piston and a large connecting rod eye for connecting the connecting rod in a rotatable manner to the crankshaft. The connecting rod may include at least one eccentric lubricating groove disposed in at least one of an inner face of the large connecting rod eye, an inner face of the small connecting rod eye, and a bearing bush arranged in the small connecting rod eye. The at least one groove may have an axis inclined with respect to an axis of at least one of the respective small connecting rod eye, large connecting rod eye, and bearing bush.

Claims

1. A connecting rod for converting a linear motion of a piston into a rotational motion of a crankshaft, comprising: a connecting rod eye for rotatably connecting to a receiving component, the connecting rod eye having an inner face extending about an axis; at least one lubricating groove disposed in the inner face of the connecting rod eye, the at least one lubricating groove extending circumferentially along the inner face about a groove axis, wherein the groove axis of the at least one lubricating groove is arranged eccentric to the axis of the inner face such that the at least one lubricating groove is interrupted in a circumferential direction on a load side of the connecting rod eye and extends over an equator and a zenith of the connecting rod eye, and the groove axis of the at least one lubricating groove runs inclined to the axis of the inner face such that the at least one lubricating groove has a depth in a radial direction that increases from a region between the equator and a nadir of the connecting rod eye over the equator and towards the zenith of the connecting rod eye; wherein the at least one lubricating groove covers a circumferential angle of greater than 180; and wherein the depth of the at least one lubricating groove is greatest at the zenith and decreases in the circumferential direction towards the load side until the at least one lubricating groove ends in the region between the nadir and the equator.

2. The connecting rod according to claim 1, wherein at least one of: the at least one lubricating groove has a rounded groove bottom; and the groove axis of the at least one lubricating groove is inclined with respect to the axis of the inner face of the connecting rod eye by at least one of a vertical plane and a horizontal plane.

3. The connecting rod according to claim 1, wherein the connecting rod eye has a tapering.

4. The connecting rod according to claim 1, wherein the load side is disposed at the nadir of the connecting rod eye, and wherein the at least one lubricating groove runs diagonally to the axis of the inner face from the region between the nadir and the equator to the zenith.

5. The connecting rod according to claim 1, wherein at least one of: the at least one lubricating groove exits on an axial side of the connecting rod eye; and at least one inflow bore is provided to supply the at least one lubricating groove with lubricant.

6. The connecting rod according to claim 1, wherein at least one of a plurality of lubricating grooves are disposed in the inner face of the connecting rod eye including the at least one lubricating groove, and the at least one lubricating groove is structured as a spirally running lubricating groove.

7. The connecting rod according to claim 1, wherein the at least one lubricating groove includes a configuration that is one of (i) bidiagonal and open towards an axial side of the connecting rod eye, (ii) helical and open towards an axial side of the connecting rod eye, and (iii) helical and closed towards an axial side of the connecting rod eye.

8. The connecting rod according to claim 1, wherein the groove axis of the at least one lubricating groove is disposed offset from the axis of the inner face between the equator and the zenith of the connecting rod eye.

9. The connecting rod according to claim 1, wherein the connecting rod eye is at least one of a small connecting rod eye and a large connecting rod eye.

10. The connecting rod according to claim 1, further comprising a bearing bush arranged in the connecting rod eye, wherein the bearing bush defines the inner face.

11. The connecting rod according to claim 1, wherein the circumferential angle covered by the at least one lubricating groove is 240 to 300.

12. A connecting rod for converting a linear motion of a piston into a rotational motion of a crankshaft, comprising: a connecting rod eye for rotatably connecting to a receiving component, the connecting rod eye having an inner face extending about an axis; at least one lubricating groove disposed in the inner face of the connecting rod eye, the at least one lubricating groove extending circumferentially along the inner face about a groove axis, wherein the groove axis of the at least one lubricating groove is arranged eccentric to the axis of the inner face such that the at least one lubricating groove is interrupted in a circumferential direction on a load side of the connecting rod eye and extends over an equator and a zenith of the connecting rod eye, and the groove axis of the at least one lubricating groove runs inclined to the axis of the inner face such that the at least one lubricating groove has a depth in a radial direction that increases from a region between the equator and a nadir of the connecting rod eye over the equator and towards the zenith of the connecting rod eye; wherein the at least one lubricating groove covers a circumferential angle of greater than 180; and wherein the load side is disposed at the nadir of the connecting rod eye and the at least one lubricating groove ends in the region between the nadir and the equator, and wherein the at least one lubricating groove runs diagonally to the axis of the inner face from the region between the nadir and the equator to the zenith.

13. An internal combustion engine, comprising: at least one connecting rod, a piston and a crankshaft, the at least one connecting rod including: a small connecting rod eye for connecting the connecting rod in a rotatable manner to a pin of the piston; a large connecting rod eye for connecting the connecting rod in a rotatable manner to the crankshaft, wherein the small connecting rod eye and the large connecting rod eye respectively have an inner face extending about an axis; and at least one lubricating groove disposed in the inner face of at least one of the small connecting rod eye and the large connecting rod eye, the at least one lubricating groove extending along the inner face circumferentially about a groove axis, wherein the groove axis of the at least one lubricating groove is arranged eccentric to the axis of the inner face such that the at least one lubricating groove extends over an equator and a zenith of the at least one of the small connecting rod eye and the large connecting rod eye and ends between the equator and a nadir of the at least one of the small connecting rod eye and the large connecting rod eye, and the groove axis runs inclined to the axis of the inner face such that the at least one lubricating groove has a depth in a radial direction that decreases from the zenith to the equator and towards the nadir until the at least one lubricating groove ends between the nadir and the equator; and wherein the at least one lubricating groove covers a circumferential angle of greater than 180, and the at least one lubricating groove is interrupted in a circumferential direction on a load side of the at least one of the large connecting rod eye and the small connecting rod eye, the nadir being arranged at the load side.

14. The internal combustion engine according to claim 13, further comprising a bearing bush arranged in the small connecting rod eye, wherein the bearing bush defines the inner face of the small connecting rod eye and the at least one groove is disposed in the bearing bush.

15. The internal combustion engine according to claim 13, wherein at least one of: the groove axis of the at least one lubricating groove is inclined by at least one of a vertical plane and a horizontal plane with respect to the axis of the inner face of the at least one of the small connecting rod eye and the large connecting rod eye; and the small connecting rod eye defines a tapering.

16. The internal combustion engine according to claim 13, wherein at least one of: the at least one lubricating groove exits on an axial side of the at least one of the large connecting rod eye and the small connecting rod eye; and at least one inflow bore is provided in the at least one connecting rod to supply the at least one lubricating groove with lubricant.

17. The internal combustion engine according to claim 13, wherein the at least one lubricating groove has a rounded groove bottom.

18. The internal combustion engine according to claim 13, wherein the groove axis of the at least one lubricating groove is disposed offset from the axis of the inner face between the equator and the nadir.

19. The internal combustion engine according to claim 13, wherein the circumferential angle covered by the at least one lubricating groove is 240 to 300.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the figures,

(2) FIG. 1 schematically shows a connecting rod according to the invention with a piston attached thereto,

(3) FIG. 2 schematically shows a geometric diagram of the eccentricity of the eccentric lubricating groove,

(4) FIG. 3A schematically shows a small connecting rod eye with a bearing bush arranged therein and a lubricating groove which is eccentric, bidiagonal and open towards the axial side,

(5) FIG. 3B schematically shows a diagram as in FIG. 3A, but with a lubricating groove that is eccentric, helical and open towards the axial side,

(6) FIG. 3C schematically shows a diagram as in FIG. 3C, but with a lubricating groove that is eccentric, helical, closed and open towards the axial side,

(7) FIG. 4A schematically shows a further diagram of a possible embodiment of the lubricating groove without an additional bearing bush,

(8) FIG. 4B schematically shows a diagram as in FIG. 4A, but with an inflow bore for lubricant.

DETAILED DESCRIPTION

(9) According to FIG. 1, a connecting rod 1 according to the invention, which is usually referred to as a con rod or push rod, for converting a linear motion of a piston 2 into a rotational motion of a crankshaft 3 has two connecting rod eyes 4, 5. The connecting rod eye 4 is referred to as the small connecting rod eye 4 and connects the connecting rod 1 rotatably to a pin of the piston 2, whereas the connecting rod eye 5 is referred to as the large connecting rod eye 5 and is connected rotatably by means of the latter to the crankshaft 3. The small connecting rod eye 4 is closed or configured as a closed bearing, whereas the large connecting rod eye 5 is configured as a split bearing (sawn or cracked). According to the invention, at least one eccentric lubricating groove 8 is provided on at least one inner face of the small connecting rod eye 4 or of a bearing bush 7 arranged therein (cf. FIGS. 3 to 4B), the axis 9 of which groove is inclined to the axis 10 of the small connecting rod eye 4. In this case, inclined can mean that the axis 9 is inclined with respect to the axis 10 of the respective connecting rod eye 4, 5 by a vertical and/or a horizontal, that is, in particular only runs diagonally in one plane but is parallel to the axis 10 in the other plane. The axis 10 of the small connecting rod eye 4 runs perpendicularly to the image plane according to FIG. 1. Of course, such a lubricating groove 8 can also be arranged in the same manner in a bearing bush 7 in the large connecting rod eye 5 or directly in the large connecting rod eye 5.

(10) The at least one lubricating groove 8 can have a rounded groove bottom, as can be seen for example in FIG. 3C. Such rounded geometries reduce in particular the notch effect that affects susceptibility to failure. It can be seen in FIG. 3A to 3C that the lubricating groove 8 is interrupted on a load side 15, that is, on the nadir 11 (bottom) and extends merely over the equator 12 and the zenith 13 (cf. FIG. 3c). The at least one lubricating groove 8 covers a circumferential angle of more than 180, preferably an angle of 240 to 300. The eccentric arrangement of the lubricating groove 8 allows in particular the oil supply in the part under high loads to be greatly improved and thereby the friction to be considerably reduced. The lubricating grooves 8 have a depth of approx. 1 to 100 m and can therefore be produced advantageously compared to oil pockets and slots. The eccentric arrangement of the lubricating grooves 8 also allows the groove to come to an end very smoothly, as a result of which the buildup in oil pressure is not impaired very much and at the same time the oil suction out of the lubricating groove 8 is promoted.

(11) The production of the at least one lubricating groove 8 can be carried out using a conventional lathe with a rotatably mounted turning tool, the cutting face of which, which is suitable for the present task, is arranged radially outwards. To produce the at least one lubricating groove 8, first the turning tool is arranged in the small connecting rod eye 4 in such a manner that the rotation axis thereof lies on the axis 10 of the small connecting rod eye 4. The turning tool is then set in rotation, the radial dimension of the turning tool being selected to be such that no contact takes place with the inner wall of the small connecting rod eye 4 or with the inner wall of the bearing bush 7 arranged in the connecting rod eye 4. The rotation axis of the turning tool is then displaced in the direction in which the lubricating groove 8 is provided. This direction runs diagonally to the axis 10, as a result of which the lubricating groove 8 increases in depth over the equator 12 towards the zenith 13 and decreases in depth on the opposite side from the zenith 13 to the equator 12. On the load side 15, that is, the nadir 11, the lubricating groove 8 is not present at all, since it already comes to an end between the equator 12 and the nadir 11. It can be seen in FIG. 2 that the lubricating groove 8 has a depth t.sub.2 in the zenith 13 that is twice the size of the vertical axial displacement t.sub.1 at the equator 12. The depth of the lubricating groove 8 increases just above the load side 15, that is, just above the nadir 11 over the equator 12 towards the zenith 13 and smoothly comes to an end on the opposite side over the equator 12 to the nadir 11. The angle of the eccentricity of the lubricating groove 8 can be adapted to the direction of the main load, producing the advantage of an uninterrupted buildup of lubricating film in the region of the bearing under high load, and the maximum possible support area of the bore face or of the bearing bush 7 is used. The oil supply in the region under high load can be further improved by eccentric multiple grooves or a plurality of eccentric lubricating grooves 8, even having different groove depths. Eccentric lubricating grooves 8 having a small depth of approx. 1 to 100 m can be produced advantageously compared to oil pockets and slots. A circumferential angle over which the lubricating groove 8 extends is usually 180 to 360, typically 240 to 300. Because the groove comes to an end very smoothly in the region between the equator 12 and the nadir 11, the buildup of lubricating pressure is not impaired very much and the oil suction out of the lubricating groove is additionally promoted.

(12) Owing to the diagonal profile of the axis 9 of the lubricating groove 8 to the axis 10 of the small connecting rod eye 4, the lubricating groove is open towards an axial side of the connecting rod eye 4 and thereby produces a self-aspirating oil supply, as can be seen in FIG. 3A to 3C.

(13) According to FIG. 3A, the lubricating groove 8 is eccentric, bidiagonal and open towards the axial side of the connecting rod eye 4, whereas the lubricating groove 8 according to FIG. 3B is eccentric, helical and open towards the axial side of the small connecting rod eye 4. In contrast, the lubricating groove 8 according to FIG. 3C is eccentric, helical, closed, and at the same time open towards the axial side. According to FIG. 3A to 3C, the small connecting rod eye 4 has a trapezoidal cross section, this being provided purely optionally. Helical means in this case an axis 9 of the lubricating grooves 8 that runs parallel to the axis 10 of the small connecting rod eye 4 and to the axis 10 of the bearing bush 7. Of course, a spirally running lubricating groove 8 can generally also be provided, as is indicated in FIG. 3C.

(14) The lubricating effect in the small connecting rod eye 4 or in a bearing bush 7 arranged there can be greatly improved with the lubricating groove 8 according to the invention, which is arranged eccentrically and runs diagonally to the axis 10 of the connecting rod eye 4, as a result of which the friction in this region can be reduced and the smooth running properties of the internal combustion engine can be improved.

(15) FIGS. 4A and 4B show a further embodiment of a possible lubricating groove 8, which in this case has an eccentric and bidiagonal configuration. A bearing bush 7 is not provided, so the lubricating groove(s) 8 are introduced directly into the connecting rod eye 4. The lubricating groove 8 according to FIG. 4B has an inflow bore 14, by means of which lubricant can be supplied. In contrast the lubricating groove 8 according to FIG. 4A is configured as a closed lubricating groove 8. Such an inflow bore 14 can of course also be provided with other lubricating groove geometries, for which reason such an inflow bore 14 is also shown with dashed lines in FIG. 3C. In this case the inflow bore 14 must of course also penetrate the bearing bush 7.

(16) Of course, the statements made above for the small connecting rod eye 4 can also be applied to the large connecting rod eye 5, the latter usually being configured, in contrast to the small connecting rod eye 4, not as a closed bearing but as a split bearing having two bearing halves. All the configurations of the lubricating groove 8 made with regard to the small connecting rod eye 4 in the description and in the claims can thus be applied unchanged to the large connecting rod eye 5. The shape of the small connecting rod eye 4 can also differ from the trapezoidal shape shown (cf. FIG. 3A to 3C) and can for example have a cylindrical or stepped shape.