Camshaft for an internal combustion engine and use therefore

Abstract

A camshaft for an internal combustion engine, with a drivable basic shaft and a cam piece which is mounted in the basic shaft, wherein the basic shaft passes through a passage in the cam piece, and the cam piece is mounted in the basic shaft in a rotationally fixed and axially displaceable manner. In the case of such a camshaft, it is provided that the basic shaft has a polygonal profile, and the passage in the cam piece has a complementary polygonal profile for receiving the basic shaft. The camshaft is preferably used in a motorcycle which has an internal combustion engine with two cylinders.

Claims

1. A camshaft for an internal combustion engine, with a drivable basic shaft and a cam piece which is mounted on the drivable basic shaft, wherein the drivable basic shaft is solid and passes through a passage in the cam piece, and the cam piece is mounted on the drivable basic shaft in a rotationally fixed and axially displaceable manner, wherein a perimeter of the drivable basic shaft has a polygonal profile, and a perimeter of the passage in the cam piece has a complementary polygonal profile for receiving the drivable basic shaft.

2. The camshaft as claimed in claim 1, wherein the polygonal profiles of the drivable basic shaft and the passage have an identical shape, wherein the cross section of the polygonal profile of the drivable basic shaft is smaller than the cross section of the polygonal profile of the passage.

3. The camshaft as claimed in claim 1, wherein each polygonal profile is of substantially square.

4. The camshaft as claimed in claim 1, wherein each polygonal profile has rounded corners.

5. The camshaft as claimed in claim 1, wherein each polygonal profile has an outwardly curved contour in a region connecting respective adjacent corners.

6. The camshaft as claimed in claim 1, wherein the drivable basic shaft is connected in the region of one end to an externally driveable drive element.

7. The camshaft as claimed in claim 1, wherein the cam piece has a slotted guide element and at least one cam part.

8. The camshaft as claimed in claim 7, wherein the cam piece has two cam parts, wherein two valves of the internal combustion engine are activatable by the two cam parts.

9. The use of a camshaft as claimed in claim 1 in a motor vehicle which has an internal combustion engine with two cylinders.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Further features of the invention emerge from the dependent claims, the attached drawing and the description of the exemplary embodiment reproduced in the drawing, without being limited thereto. In the drawing:

(2) FIG. 1 shows a three-dimensional view of the camshaft according to aspects of the invention,

(3) FIG. 2 shows a three-dimensional view of the basic shaft used in the camshaft according to FIG. 1,

(4) FIG. 3 shows a three-dimensional view of the cam piece used in the camshaft according to FIG. 1,

(5) FIG. 4 shows a section through the cam piece, shown in FIG. 3, in a section perpendicular to the axis of rotation of the cam piece.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 illustrates a camshaft 1 for an internal combustion engine, this preferably being an internal combustion engine with two cylinders for use in a motorcycle.

(7) The camshaft 1 has a driveable basic shaft 2 and a cam piece 3 which is mounted in the basic shaft 2. The basic shaft 2 passes through a passage 4 in the cam piece 3. The cam piece 3 is mounted in the basic shaft 2 in a rotationally fixed and axially displaceable manner. In order to drive the basic shaft 2, the latter is connected in the region of one end to an externally driveable drive element 5. The cam piece 3 has, according to FIG. 3, two cam parts 6 and a slotted guide element 7 between the latter. Each cam part 6 is provided with two cam pairs 8. Each cam pair 8 has two cams 9, 10, wherein, as a consequence of axial displacement of the cam piece 3, the one cam 9 or the other cam 10 can be brought into engagement with an inlet valve or outlet valve of the internal combustion engine.

(8) According to FIG. 2, the basic shaft 2 has a polygonal profile 11, and the passage 4 in the cam piece 3, has, according to FIG. 4, a complementary polygonal profile 12 for receiving the basic shaft 2. The polygonal profiles 11 and 12 are of identical configuration with respect to the cross-sectional design thereof, namely are of square design with rounded corners. That region of the polygonal profile 11 or 12 which connects respective adjacent corners has a slightly outwardly curved contour. The cross section of the polygonal profile 11 for the basic shaft 2 is somewhat smaller in size than the cross section of the polygonal profile 12 for the passage 4 of the cam piece 3. Accordingly, the cam piece 3 can be displaced with respect to the basic shaft 2 in the longitudinal extent thereof with play. The displacement of the cam piece 3 takes place in a known manner by means of slotted guide pins which can be brought into engagement with the slotted guide part 7.

LIST OF REFERENCE NUMBERS

(9) 1 Camshaft 2 Basic shaft 3 Cam piece 4 Passage 5 Drive element 6 Cam part 7 Slotted guide element 8 Cam pair 9 Cam 10 Cam 11 Polygonal profile 12 Polygonal profile