Piston for a disk brake, disk brake having at least one piston, and series of pistons

A piston for a disk brake, the piston comprising:

• a contact surface for a brake lining, an outer part forming a piston skirt and an inner part inserted into the outer part;
• the inner part has an opening on a side thereof facing away from the contact surface and, in an interior thereof, a receptacle via which the piston is pressurizable by at least one of a hydraulic fluid or by an actuating means of a parking brake drive;
• a cavity formed between the outer part and the inner part, the cavity is closed fluid-tight by at least one fluid-tight connection between the inner part and the outer part to prevent ingress of hydraulic fluid from the receptacle of the inner part into the cavity
• wherein the outer part has a retaining opening for the inner part axially spaced with respect to a longitudinal axis of the piston from an insertion opening for the inner part, and the inner part is arranged in the retaining opening for support on the outer part;
• an insertion opening of the outer part for the inner part is closed fluid-tight by a first of the at least one fluid-tight connection between the outer part and the inner part;
• the outer part has a support section on which the retaining opening for the inner part is formed and via which the inner part is supported on the outer part in a feed direction of the piston;
• and
• a second of the at least one fluid-tight connection at least one of closes the retaining opening fluid-tight or is formed between the support section of the outer part and the inner part.