Camshaft for the valve drive of an internal combustion engine with a variable valve opening duration

A camshaft for a valve drive of an internal combustion engine having a variable valve opening time, the camshaft comprising:

• an outer shaft;
• an inner shaft that extends through the outer shaft, with the inner shaft being held rotatably with respect to the outer shaft;
• a first cam having a multiple-piece configuration and comprising a first part cam and a second part cam, wherein either the first part cam or the second part cam is connected fixedly to the outer shaft so as to rotate with the outer shaft, wherein the one of the first part cam and the second part cam that is not connected fixedly to the outer shaft so as to rotate with the outer shaft is connected fixedly to the inner shaft so as to rotate with the inner shaft;
• a bearing inner ring of a shaft bearing being held on the outer shaft, wherein the second part cam of the first cam forms at least one part of the bearing inner ring;
• and
• a second cam adjacent to the first cam, the second cam comprising a first part cam and a second part cam separate from the first part cam and the second part cam of the first cam, wherein the bearing inner ring has a multiple-piece configuration, and the second part cam of the second cam forms at least one other part of the bearing inner ring.