Door drive for vehicle sliding door system

A vehicle sliding door system with a door portal and a door opening, at least one sliding door with a front lateral edge and a rear lateral edge, and a door driving unit for displacing the sliding door, wherein the door driving unit comprises:

• a cable having a first end attached to the sliding door in the region of the front vertical lateral edge, and having a second end in the region of the rear vertical lateral edge, and
• a coupling member, which is connected to the cable and which is connected to a motor, which is attached on the door portal laterally next to the door portal and which drives the coupling member such that the cable is movable along a longitudinal extent in both directions of movement and displaces the sliding door,
• wherein a first roller, a second roller, and a third roller, via which the cable is redirected, are rotatably mounted on the door portal, with the following cable portions resulting therefrom:
• a first portion extending in the horizontal direction from a first attaching means to the first roller,
• a second portion extending from the first roller in the vertical direction to the second roller,
• a third portion extending from the second roller in the vertical direction to the third roller, and
• a fourth portion extending from the third roller in the horizontal direction to a second attaching means,
• wherein a cable pulley, on which the cable is configured to be spooled up and from which the cable is configured to be unspooled, is attached to the door portal in the path of the cable, wherein the cable pulley is driven by the motor, wherein the cable pulley is arranged at approximately a same height as the two attaching means in the vertical direction.