In modern internal combustion engines, camshaft adjusting systems are used for the variable adjustment of the control times of gas exchange valves, in order for it to be possible for the phase relation between the crankshaft and the camshaft to be designed in a defined angular range in a variable manner. Hydraulic camshaft adjusting systems usually require energy for the adjusting operation, which energy is made available to them via a pressure medium system. Here, the energy which is available in the pressure medium system is formed from the product of pressure medium pressure and pressure medium volumetric flow. During an adjustment of one or more camshafts of the internal combustion engine, the required pressure medium flow, which flows into the camshaft adjuster, is branched off by means of at least one control valve which is connected upstream of the camshaft adjuster. At the same time, an equally large pressure medium flow passes out of the camshaft adjuster back into the pressure medium reservoir of the pressure medium system, and is therefore fed to the pressure medium system again. As a result of the removal of the pressure medium flow out of the pressure medium system, the pressure medium pressure falls as a consequence. As a result, the energy is also reduced which is available to the camshaft adjuster for the adjustment. In order to prevent this, a pressure accumulator can be provided which makes pressure energy available to the camshaft adjusting system in the case of a drop in the pressure medium pressure, for equalization purposes.
A volume accumulator which communicates with a camshaft adjuster is described in a patent application which has already been filed by the applicant under the reference number DE 10 2009 049 459.6 but has not yet been published. The volume accumulator is formed in a cavity of a camshaft and is connected, via a pressure medium channel which is arranged in the camshaft, to a control valve which serves to supply the camshaft adjuster with pressure medium. In this embodiment, the circumstance has a disadvantageous effect that the control valve and volume accumulator are configured separately. As a result, said components have to be mounted individually, in each case on one side of the camshaft, and are connected to one another by way of a pressure medium channel in the camshaft. In addition, throttling losses can occur in the pressure medium channel, in particular because of cross-sectional constrictions, additional baffles or deflection means, as a result of which the function of the pressure accumulator is impaired.