<p>The spindle motor has an electric motor with a rotor connected with a threaded spindle (5). Threads of the threaded spindle stay in connection with threads of a spindle nut (6) that is connected with a piston rod (14). The spindle nut is axially guided with the piston rod into a housing part (7) using a guide ring (9) that is axially connected with the spindle nut and the piston rod. The threaded spindle is supported in another housing part (4) using a support (18). A cooling channel is formed in the latter housing part and runs in a circumferential direction of the latter housing part.</p>
