BEARING ARRANGEMENT FOR A CAMSHAFT OF AN INTERNAL COMBUSTION ENGINE AND CRANKCASE WITH SAME

Abstract

A bearing arrangement for a camshaft of an internal combustion engine, the internal combustion engine including a crankcase and a camshaft including a camshaft gear wheel and a side including a shaft end allocated to the camshaft gear wheel, includes: an axial bearing configured for supporting the camshaft on the side of the shaft end, the axial bearing including a plain bearing body, which includes a mounting surface, is crescent-shaped, and is configured for axially supporting the camshaft and for being attached to the crankcase by way of the mounting interface.

Claims

1. A bearing arrangement for a camshaft of an internal combustion engine, the internal combustion engine including a crankcase and a camshaft including a camshaft gear wheel and a side including a shaft end allocated to the camshaft gear wheel, the bearing arrangement comprising: an axial bearing configured for supporting the camshaft on the side of the shaft end, the axial bearing including a plain bearing body, which includes a mounting surface, is crescent-shaped, and is configured for axially supporting the camshaft and for being attached to the crankcase by way of the mounting interface.

2. The bearing arrangement according to claim 1, wherein the camshaft includes a bearing groove that is circumferentially incorporated into a circumference of the camshaft, the plain bearing body (a) is configured for being inserted into the bearing groove for an axial support of the camshaft in order to support the camshaft axially in an inserted state of the plain body bearing, and (b) is configured for being attached in the inserted state to the crankcase by way of the mounting interface.

3. The bearing arrangement according to claim 1, wherein the plain bearing body includes a bearing groove and is configured for being slid onto a corresponding shoulder of the camshaft for an axial support of the camshaft, for axially supporting the camshaft in a slid-on state, and for being attached to the crankcase in the slid-on state by way of the mounting interface.

4. The bearing arrangement according to claim 1, wherein the mounting interface includes a contact surface corresponding to a contact surface of the crankcase.

5. The bearing arrangement according to claim 4, wherein the plain bearing body is configured for being axially screwed to the crankcase.

6. The bearing arrangement according to claim 5, wherein the plain bearing body includes an axial direction and a region of the mounting interface, wherein the plain bearing body includes an increased material thickness in the axial direction in the region of mounting interface.

7. The bearing arrangement according to claim 6, wherein the plain bearing body includes a first side, the increased material thickness being formed as a protrusion on the first side.

8. The bearing arrangement according to claim 1, wherein the plain bearing body includes a first bearing surface and a second bearing surface opposite first bearing surface, wherein the camshaft includes a bearing groove that is circumferentially incorporated into a circumference of the camshaft, the bearing groove including two groove edges opposite one another, and wherein the first bearing surface and the second bearing surface in an inserted state each facing respectively one of the two groove edges.

9. The bearing arrangement according to claim 8, wherein an axial distance between opposite ones of the two groove edges is greater than an axial distance between opposite ones of the first bearing surface and the second bearing surface, such that, in the inserted state, the bearing arrangement is configured such that an axial bearing gap forms between the first bearing surface and the second bearing surface and the two groove edges respectively.

10. The bearing arrangement according to claim 9, wherein the plain bearing body includes a fluid channel that can be connected in a fluid-conducting manner to a lubricant supply, wherein the fluid channel includes a first outlet and a second outlet respectively for the first bearing surface and the second bearing surface, the first outlet and the second outlet opening respectively into the first bearing surface and the second bearing surface.

11. The bearing arrangement according to claim 10, wherein the plain bearing body includes an inlet side and an outlet side in a circumferential direction of the plain bearing body relative to a direction of rotation of the camshaft.

12. The bearing arrangement according to claim 11, wherein the first outlet and the second outlet are positioned closer to the inlet side than to the outlet side.

13. The bearing arrangement according to claim 12, wherein the first outlet and the second outlet are aligned coaxially relative to one another.

14. The bearing arrangement according to claim 8, wherein the first bearing surface and the second bearing surface have an inlet end and an end face in a circumferential direction of the plain bearing body at the inlet end, where a chamfer is formed respectively, such that the plain bearing body is tapered in a wedge shape at the inlet end.

15. The bearing arrangement according to claim 1, wherein the bearing arrangement further includes a radial bearing on the side of the shaft end, which supports the camshaft radially at the crankcase, wherein the radial bearing is arranged in a bearing seat of the crankcase, and wherein the axial bearing is arranged between the radial bearing and the camshaft gear wheel.

16. An internal combustion engine, comprising: a crankcase; a camshaft; a camshaft gear wheel, which is attached to the camshaft and is configured for driving the camshaft, the camshaft including a side including a shaft end allocated to the camshaft gear wheel; and a bearing arrangement for the camshaft, the bearing arrangement including an axial bearing configured for supporting the camshaft on the side of the shaft end, the axial bearing including a plain bearing body, which includes a mounting surface, is crescent-shaped, and is configured for axially supporting the camshaft and for being attached to the crankcase by way of the mounting interface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0043] FIG. 1 is a schematic spatial representation of a crankcase according to an optional design example;

[0044] FIG. 2 is a partially sectioned schematic top view of the crankcase according to FIG. 1, from a different perspective;

[0045] FIG. 3 is a partially sectioned schematic top view of the crankcase according to FIG. 1 and FIG. 2, from a different perspective;

[0046] FIG. 4 is a partially sectioned schematic top view of the crankcase according to FIG. 1 to FIG. 3, from a different perspective;

[0047] FIGS. 5A and 5B are top views onto a wall of the crankcase according to FIG. 1 to FIG. 3 with camshaft gear wheel removed; and

[0048] FIGS. 6A, 6B, and 6C are various partial sectional views of a plain bearing body for the crankcase represented in FIG. 1 to FIGS. 5A, 5B.

[0049] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one embodiment of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0050] FIG. 1 shows crankcase 1 of internal combustion engine 100. Crankcase 1 has a wall 3 in which camshaft 5 is mounted by way of a bearing arrangement (see FIG. 2 to FIG. 6).

[0051] Camshaft 5 has shaft end 7 to which camshaft gear wheel 9 is attached. Camshaft gear wheel 9 is designed to be driven by way of a transmission and to rotate camshaft 5 in direction of rotation B about a rotation axis A. Crankcase 1 can be closed with one or more covers which however are not necessary for explanation of the present invention and are therefore not shown.

[0052] As can be seen from FIG. 2 to FIG. 5, axial bearing 11 is arranged between camshaft gear wheel 9 and wall 3. Axial bearing 11 has a crescent-shaped plain bearing body 13. Plain bearing body 13 has a bearing section 15 that is inserted into bearing groove 17, which is provided circumferentially on camshaft 5.

[0053] Plain bearing body 13 moreover has a mounting interface 19, by way of which plain bearing body 13 is attached to wall 3.

[0054] The assembly optionally is performed in such a way that camshaft 5 is pushed into its approximate designated operating position in the direction of axis A. Then, optionally with camshaft gear wheel 9 not yet assembled, plain bearing body 13 is engaged laterally with camshaft 5 so that bearing portion 15 dips into bearing groove 17.

[0055] Plain bearing body 13 is then brought into contact with wall 3 via the mounting interface and attached, for example, axially screw-fastened, as shown in the present design example. For this purpose, the bearing arrangement has a number, in particular a plurality, of screws 21 that are installed along a predetermined pattern on plain bearing body 13 and on wall 3.

[0056] To accommodate plain bearing body 13, wall 3 has a contact surface 23 corresponding to mounting interface 19 of the latter, which can be designed as one piece or segmented into several spaced-apart parts. After mounting plain bearing body 13 and securing it to wall 3, camshaft gear wheel 9 can finally be connected in a known manner with shaft end 7 of camshaft 5.

[0057] Meshing of plain bearing body 13 into camshaft 5, particularly into its bearing groove 17, is shown in more detail in FIG. 3 and FIG. 4.

[0058] Bearing groove 17 has a groove bottom 25, as well as a first groove edge 27 and a second groove edge 29 arranged opposite.

[0059] Edges 27, 29 are optionally axially aligned with their surface-normal and parallel to each other.

[0060] Bearing section 15 has a first bearing surface 31 and an opposite second bearing surface 33. First bearing surface 31 is optionally oriented towards groove edge 27, while second bearing surface 33 is oriented towards second groove edge 29. Bearing surfaces 31, 33 are optionally aligned axially with their surface normal and are parallel to each other.

[0061] Camshaft 5 is supported radially in wall 3 of crankcase 1 by way of a radial bearing 34 designed as a plain bearing, so that axial bearing 11 acts adjacent and at a distance from radial bearing 34 on one hand and camshaft gear wheel 9 of camshaft 5 on the other.

[0062] Seating of camshaft 5 is ensured through precision machining of contact surface 23 of wall 3 on one the hand and dimensional machining of mounting interface 19 on the other. As further illustrated in FIG. 4, screws 21 extend axially from a first side S1 of plain bearing body 13 to a second side S2 of the plain bearing body (compare FIG. 6).

[0063] The material thickness in the radial outer region of bearing body 13, in other words, radially outside bearing section 15, has an increased material thickness in axial direction, which results in higher stability of bearing body 13 and an increased gripping length for screws 21.

[0064] FIG. 3 and FIG. 4 show a cross section through crankcase 1 along axis A.

[0065] The region of increased material thickness extends as a protrusion towards axis A on first side S1 of plain bearing body 13.

[0066] FIG. 5-specifically divided into FIG. 5A and FIG. 5B shows the crescent-shaped structure of plain bearing body 13. The term crescent-shape describes that bearing section 15 takes an essentially semicircular progression in order to best fit into bearing groove 17. It is possibleand provided in optional versionsto extend the shoulders at an inlet side 37 and an outlet side 39 positioned opposite in the circumferential direction. However, the arc of contact that bearing section 15 takes around camshaft 5 in bearing groove 17 remains limited to 180 or less to maintain assembly capability.

[0067] FIG. 5A shows a top view of a plain bearing body in its mounted position on wall 3 of crankcase 1 with blocked out camshaft gear wheel 9.

[0068] Plain bearing body 13 is designed approximately semicircular from inlet side 37 to outlet side 39 in operating rotation direction B. Axial bearing 11 shown in FIG. 5A and FIG. 5B is fluidically connected to a lubrication source 43 via a supply channel 41 in wall 3 of crankcase 1 for the supply of lubricant.

[0069] As shown, the outer contour of the plain bearing body can also be designed to be essentially semicircular. However, the exact contour along mounting interface 19 with screw fittings 21 is not functionally essential for the bearing itself, but is rather of economic interest in regard to manufacturing and depends on the configuration of screws 21, supply channel 41, etc.

[0070] As shown in FIG. 5B, plain bearing body 13 has a fluid channel 45 as shown in the cross section of its interior, through which lubricant is directed towards inlet side 37 in the direction of arrow P1.

[0071] At inlet side 37, plain bearing body 13 has two outlets 47, 49, one of which opens towards first side S1 and the other towards second side S2 into bearing surfaces 31, 33, with outlets 47, 49 being coaxially aligned, symmetrically to each other.

[0072] By symmetrically introducing lubricant through fluid channel 45 and outlets 47, 49, a hydrodynamic centering of plain bearing body 13 in bearing groove 17 is achieved when camshaft 5 rotates at the intended operational speed. Fluid channel 45 can, as shown in the illustrated embodiment, be designed as a combination of fluid-conductive connected linear bores, which are sealed at the ends with suitable plugs.

[0073] Since the distance between bearing surfaces 31, 33 in axial direction is somewhat less than the distance between corresponding groove edges 27, 29 of bearing groove 17, a bearing gap is formed on both sides of bearing section 15 of plain bearing body 13, which is filled with lubricant during operation to enable essentially frictionless gliding of camshaft 5 in axial bearing 11.

[0074] FIG. 6 shows several additional details of plain bearing body 13 for the bearing arrangement and the crankcase of FIGS. 1 to 5. FIG. 6 is divided into the three details: FIGS. 6A, 6B, and 6C. In FIG. 6A, first side S1 of plain bearing body 13 is shown.

[0075] Radially outside adjacent to bearing section 15 is the region of the assembly interface described above with increased material thickness. At the points where screws 21 (see FIG. 1 to FIG. 5) are to be passed through the corresponding through-holes 35 of plain bearing body 13, a raised eye 51 with a supporting surface 53 is formed on first side S1, with supporting surface 53 being designed to fit against a screw head of screws 21.

[0076] In FIG. 6A, the view of first outlet 47 for the lubricant is moreover made available.

[0077] FIG. 6B shows a cross-section through plain bearing body 13, again illustrating the progression of fluid channel 45. Fluid channel 45 has a first sub-channel 45a and a second sub-channel 45b, which are each tightly sealed at the end by appropriate plugs 55.

[0078] FIG. 6C shows the view from the outside onto second side S2 of plain bearing body 13. Second side S2, has a flat surface 57 that transitions in a continuous manner into bearing surface 31, optionally forming a continuous flat surface with it.

[0079] On inlet side 37, bearing surface 31 has a front side 59, on which a bevel 61 is arranged both on first side S1 and on second side S2. Bevels 61 each optionally have an angle relative to respective bearing surface 31, 33 of 2 to 10, optionally 4 to 6, optionally 5, thereby creating a wedge-shaped taper towards front side 59. This simplifies the insertion of plain bearing body 13 into bearing groove 17.

[0080] In addition, inlet 63 of fluid channel 45 is shown in FIG. 6C, which can be fluidically connected to lubricant source 43 and supply channel 41, from which the lubricant can be conveyed through fluid channel 45 to outlets 47, 49.

[0081] The arrangement outlined in FIG. 1 to FIG. 6 can be easily transformed in a short time from a fully disassembled to a fully assembled state with just a few manipulations and can be maintained easily and manufactured at low cost. The quality of the axial bearing is in no way inferior to conventional axial bearings.

COMPONENT IDENTIFICATION LISTING

[0082] 1 Crankcase [0083] 3 wall [0084] 5 camshaft [0085] 7 shaft end [0086] 9 camshaft gear wheel [0087] 11 axial bearing [0088] 13 plain bearing body [0089] 15 bearing section [0090] 17 bearing groove [0091] 19 mounting interface [0092] 21 screws [0093] 23 contact surface [0094] 25 groove bottom [0095] 27 first groove edge [0096] 29 second groove edge [0097] 31 first bearing surface [0098] 33 second bearing surface [0099] 34 plain bearing/radial bearing [0100] 35 through-bore [0101] 37 inlet side [0102] 39 outlet side [0103] 41 supply channel [0104] 43 lubricant source [0105] 45 fluid channel [0106] 45a first partial channel [0107] 45b second partial channel [0108] 47,49 outlets [0109] 53 support surface [0110] 55 plug [0111] 57 flat surface [0112] 59 end face [0113] 61 chamfer [0114] 100 combustion engine [0115] A rotational axis [0116] B operational direction of rotation [0117] P1 arrow [0118] S1 first side [0119] S2 second side

[0120] While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.