LEVER FOR THE VALVE ACTUATION OF AN INTERNAL COMBUSTION ENGINE

Abstract

A lever for the valve actuation of an internal combustion engine, which is mounted such that it can pivot about an axis and has a contact surface for a valve stem end and a contact surface for a cam of a camshaft, is formed as a sheet metal rocker lever having an inverse U-shaped base including a top section and two parallel side walls integral thereto, wherein the axis is arranged at one longitudinal end of the lever, and a valve contact lug having the contact surface for the valve stem end is arranged at the other longitudinal end.

Description

FIELD OF THE INVENTION

The invention relates to a lever for the valve actuation of an internal combustion engine, which is supported so that it can pivot about an axis and has a contact surface for a valve stem end and a contact surface for a cam of a camshaft.

Such a lever is provided for use in engines for motorcycles. Such levers are typically used in motorcycle engines with more than two valves per cylinder, because then two camshafts are also provided for actuation.

From publication DE 42 34 868 C2, a rocker arm that is supported so that it can pivot about an axis in a cylinder head not shown in more detail is known for a valve train in addition to a cam follower. The axis is located there in the middle area of the lever. A valve lash compensation device forms, on one longitudinal end of the lever, a contact surface for a valve stem end, while a contact surface for a cam is located on the other longitudinal end. This contact surface is, however, formed by the outer circumferential surface of a roller, which requires a needle bearing for its rotatable arrangement.

In previous production methods for pivot arms that can be used in valve trains of motorcycle engines, the lever material is forged, sintered, or cast.

BACKGROUND

The invention is based on the object of providing an alternative to cast and forged swinging arms for the lever. Through the use of shaping and assembly techniques, a lever is to be created that is equivalent to forged and cast levers in mass, stiffness, and inertia and that makes it possible to comply with the installation space necessary for previously known levers.

SUMMARY

This objective is achieved according to the invention in that the lever is formed as a sheet metal rocker arm with an inverted U-shaped base body including a top section and two parallel side walls integral with this section, wherein the axis is arranged on one longitudinal end of the lever and a valve contact lug with the contact surface for the valve stem end is arranged on the other longitudinal end.

On the longitudinal end of the lever facing away from the axis, the valve contact lug can be arranged on the lever bottom side and a contact surface for a cam can be arranged on the lever top side.

This sheet metal solution thus provides a U-profile-shaped base body on which the two contact surfaces for the cam and for the valve stem end are arranged on one of the two longitudinal ends of the lever, while the axis is located on the other longitudinal end.

The contact surface for the valve stem end and the contact surface for the cam can be coated as sliding surfaces. The lever area containing the contact surface for the cam can be constructed integrally with the top section of the base body and the top section can have a stiffening rib.

A simple production option of the lever is then given when the lever area that contains the valve contact lug with the contact surface for the valve stem end is constructed integrally with the top section, is bent toward the side walls, and is connected with a positive fit to these walls. If at least one recess is then arranged on the valve contact lug on each side pointing toward a side wall of the lever, the valve contact lug can be fixed with a positive fit on each side wall by a swaged section, wherein the material of the bottom section of a side wall is pressed into the recess of the valve contact lug.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention is shown in the drawing and is described in more detail below. Shown are:

FIG. 1 a sheet metal rocker arm in the not yet finished state with a formed valve contact lug in perspective view,

FIG. 2 the sheet metal rocker arm according to FIG. 1 in a side view,

FIG. 3 the sheet metal rocker arm in the finished state, the valve contact lug is bent toward its side walls, and is connected there to the lever with a positive fit in perspective view,

FIG. 4 another perspective view of the sheet metal rocker arm according to FIG. 3,

FIG. 5 an end view of the sheet metal rocker arm according to FIG. 3,

FIG. 6 the sheet metal rocker arm according to FIG. 3 in a bottom view,

FIG. 7 the sheet metal rocker arm according to FIG. 3 in a side view,

FIG. 8 the sheet metal rocker arm according to FIG. 3 in a top view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A lever according to the invention is constructed as a sheet metal rocker arm 1 with a deep-drawn base body made from sheet metal which has been shaped during the deep drawing process into an inverted U-shape. The base body contains a top section 2 that attaches to two parallel side walls, namely, according to the drawing, a front side wall 3 with a bottom section 4 and a rear side wall 5 with a bottom section 6.

The sheet metal rocker arm 1 has, on its one longitudinal end on the top side, a contact surface 7 for a cam of a not-shown camshaft. On this longitudinal end there is, on the bottom side of the lever 1, a contact surface 8 for a valve stem end of a not-shown motor valve. On the other longitudinal end of the lever 1 there is the rocker arm axis 9 for which aligned holes 10 and 11 are punched out from the sheet metal from the side walls 3 and 5.

The contact surface 8 for the valve stem end is located on a valve contact lug 12 that is constructed integrally with the base body and is also punched out from the sheet metal. The valve contact lug 12 has recesses 13 on its sides adjacent to the side walls 3 and 5. It is bent according to the required contours of the curvature of the contact surface 8 in the valve contact and the contact surface 7 in cam contact on the base body, as FIGS. 3 to 8 show. In FIGS. 1 and 2, a shaping stage of the sheet metal rocker arm 1 is shown in which the valve contact lug 12 is not yet completely bent, so that the recesses 13 of the valve contact lug 12 can be identified.

After the valve contact lug 12 has been bent over so that it contacts with its bottom side on the bottom sections 4 and 6 of the side walls 3 and 5, material is pressed out from the bottom sections 4 and 6 into the recesses 13 of the valve contact lug 12 with a swaging tool, so that the valve contact lug 12 is connected in an undetachable manner on each side with a positive fit with each side wall 3 and 5 of the sheet metal rocker arm 1 due to these swaged sections 14.

LIST OF REFERENCE NUMBERS

• 1 Sheet metal rocker arm
• 2 Top section
• 3 Front side wall
• 4 Bottom section
• 5 Rear side wall
• 6 Bottom section
• 7 Contact surface for a cam
• 8 Contact surface for a valve stem end
• 9 Axis
• 10 Hole
• 11 Hole
• 12 Valve contact lug
• 13 Recess
• 14 Swaged section

Claims

1. A lever for the valve actuation of an internal combustion engine, which is supported to pivot about an axis and having a contact surface for a valve stem end and a contact surface for a cam of a camshaft, the lever comprising a sheet metal rocker arm with an inverted U-shaped base body including a top section and two parallel side walls formed integrally with the top section, the axis is arranged at one longitudinal end of the lever, and on another longitudinal end, a valve contact lug with the contact surface for the valve stem end is arranged.

2. The sheet metal rocker arm according to claim 1, wherein the valve contact lug is arranged on a bottom side on the longitudinal end facing away from the axis and a contact surface for a cam is arranged on a top side of the lever.

3. The sheet metal rocker arm according to claim 2, wherein the contact surface for the valve stem end and the contact surface for the cam are coated as sliding surfaces.

4. The sheet metal rocker arm according to claim 2, wherein the lever area containing the contact surface for the cam is constructed integrally with the top section.

5. The sheet metal rocker arm according to claim 4, wherein the top section has a stiffening rib.

6. The sheet metal rocker arm according to claim 2, wherein the lever area that contains the valve contact lug with the contact surface for the valve stem end, is constructed integrally with the top section, is bent toward the side walls, and is connected with a positive fit to said side walls.

7. The sheet metal rocker arm according to claim 6, wherein at least one recess is arranged on each side of the valve contact lug pointing respectively toward one of the side walls of the lever.

8. The sheet metal rocker arm according to claim 7, wherein the valve contact lug is fixed with a positive fit on each of the side walls by a swaged section, and material of bottom sections of each of said side walls is pressed into the recesses of the valve contact lug.