A camshaft for an internal combustion engine may include a shaft and at least one component that is joined to said shaft. The component may be connected via a joint surface of the component to a joint surface of the shaft. At least one of the joint surface of the component and the joint surface of the shaft may have a predefined roughness only partially on load-critical regions.

In a method for manufacturing a camshaft for an internal combustion engine a metal tubular element is expanded within a mold with the aid of a fluid at high pressure fed into the tubular element and with a simultaneous axial compression of the tubular element. The cams of the camshaft are formed in subsequent steps, starting from intermediate cams and ending with end cams. In a first step of the method, the intermediate cams are formed in a first mold. In a subsequent step, the end cams are formed within auxiliary molds which surround, only throughout a predetermined length, end portions of the tubular element which project from the mold which surrounds the already formed intermediate cams. In this subsequent step, the tubular element is compressed axially by axially displacing two clamp members, which grip and surround completely, throughout a predetermined length, the end portions of the tubular element which project outwardly from the auxiliary molds.

A method for manufacturing an assembled camshaft for valve-controlled internal combustion engines, in which at least one cam disc with a base circle region and cam region is machined on the running surface and has a cam-disc recess, includes shrinking the cam disc onto a corresponding shaft designed with a defined dimensional overlap by cooling the shaft and heating the cam disc. Temporally before being shrunk onto the shaft, the at least one cam disc is clamped by a clamping device such that a tension force acts on the recess wall region, which defines the cam-disc recess, the tension force corresponding to a predetermined extent to the state of stresses and/or deformation state of the recess wall region after the operation of shrinking the cam disc onto the corresponding shaft. The running-surface machining of the at least one cam disc takes place when the cam disc is clamped by the clamping device.

A method for permanently fastening a cam on a cam carrier may involve positioning the cam on the cam carrier in a predefined axial and angular position. By way of the positioning, an end face of the cam carrier is aligned with an end face of the cam. The method may also involve positioning a cam segment formed by the cam carrier and the cam in an assembly device. The cam carrier may then be deformed such that the cam is secured at least in a form-fitting or force-fitting manner against movement in an axial direction on the cam carrier. A deformation tool of the assembly device may be advanced in an axial direction onto the end face of the cam carrier, and the cam carrier may be deformed such that material of the cam carrier is forced outward in a radial direction against the cam.

A method for permanently fastening a cam on a cam carrier may involve positioning the cam on the cam carrier in a predefined axial and angular position. By way of the positioning, an end face of the cam carrier is aligned with an end face of the cam. The method may also involve positioning a cam segment formed by the cam carrier and the cam in an assembly device. The cam carrier may then be deformed such that the cam is secured at least in a form-fitting or force-fitting manner against movement in an axial direction on the cam carrier. A deformation tool of the assembly device may be advanced in an axial direction onto the end face of the cam carrier, and the cam carrier may be deformed such that material of the cam carrier is forced outward in a radial direction against the cam.

The invention relates to a camshaft, especially for motor vehicle engines, comprising a hollow outer shaft (1) and an inner shaft (2) arranged coaxially in the outer shaft (1) and mounted in such a way that it can rotate in relation to the outer shaft (1). Said camshaft also comprises first cams (3a) arranged on the outer shaft (1) in a rotationally fixed manner, and second cams (3b) that are arranged on the outer shaft (1) and fixed to the inner shaft (2). According to the invention, a supporting element (7) is provided on at least one of the end regions of the inner shaft (2), said supporting element projecting past the outer shaft (1) in the radial direction. An outer peripheral surface (8) of the outer shaft (1) and an associated inwardly facing surface (9) of the supporting element (7) form a radial bearing.

A clamping device for manufacturing an assembled camshaft for valve-controlled internal combustion engines, in which at least one cam disc with a base circle region and cam region is machined on the running surface and has a cam-disc recess, includes shrinking the cam disc onto a corresponding shaft designed with a defined dimensional overlap by cooling the shaft and heating the cam disc. Before being shrunk onto the shaft, the at least one cam disc is clamped by the clamping device such that a tension force acts on the recess wall region, the tension force corresponding to a predetermined extent to the state of stresses and/or deformation state of the recess wall region after the operation of shrinking the cam disc onto the corresponding shaft. The running-surface machining of the at least one cam disc occurs when the cam disc is clamped by the clamping device.

A device for producing a functional shaft and a functional shaft are provided in which a functional element which is provided with a pocket is inserted into a retaining element, a shaft is inserted into the pocket, and a force applied to the functional element while the shaft is being inserted into the pocket is measured.

A camshaft-manufacturing method includes: a split die group preparation step; a processing preparation step of preparing a cam including a through-hole, a cam body which is smaller than each of the cam accommodation portions, and ribs which are provided on both sides in a thickness direction of the cam body and configured to be fitted into the rib accommodation portions, and a hollow shaft, accommodating the cam body in the cam accommodation portion and fitting the ribs in the rib accommodation portion, and inserting the hollow shaft into the through-hole of the cam; and a processing step of performing hydroform processing, and fixing the cam to the hollow shaft by expanding the hollow shaft.

A method for obtaining a camshaft for an internal-combustion engine having a structure made of a single piece includes obtaining the camshaft by starting from a metal tubular element. The cams are obtained by expanding the tubular element within a die using high-pressure fluid. The tubular element can have an enlarged thickness in portions that are to form the cams. Forming with high-pressure fluid can be obtained using gas or liquid (for example, water or oil) at high pressure, at room temperature or at a higher temperature. The piece obtained is subjected to thermal treatment and to a grinding operation.