Longitudinal seat adjustment device

1. A longitudinal seat adjustment device for use in a motor vehicle that includes a chassis, said device comprising:

a lower rail configured to be fixed to the chassis, inside the lower rail, an upper rail that is configured to be attached to a seat and propelled by a motor;

a spindle sitting inside the upper rail and having its respective ends fixed to the lower rail; and

a transmission fixedly coupled to the upper rail and arranged in axially movable fashion with respect to the lower rail, where recesses are located in opposite side walls of the upper rail and into which a thrust ring, fixed to the spindle and sitting with its principal surface transverse to the longitudinal axis of the spindle, intrudes and is pressed against the side walls of the upper rail in the case of a crash.

2. The device according to claim 1 , where at least one of the side walls has a notch through which a flexible shaft coupled to a drive motor is guided.

3. The device according to claim 1 , where the side walls are pressed into the interior of the upper rail and in that the transmission housing brace itself against these slotted bridges.

4. A longitudinal seat adjustment device for use in a motor vehicle that includes a chassis, said adjustment device comprising:

a lower rail configured to be fixed to the chassis, inside which lower rail is an upper rail, to which a seat is attached, and adapted to be propelled by a motor; and

a spindle inside the upper rail and having its respective ends fixed to the lower rail, a transmission fixedly coupled to the upper rail is arranged in axially movable fashion, wherein the transmission is clampingly held in the upper rail and has a transmission housing whose opposite housing walls lie between wall parts of the upper rail and whose upper wall projects from the upper rail, where the transmission housing comprises two plastic housing shells, which are connected to one another by ultrasonic welding.

5. A longitudinal seat adjustment device for use in a motor vehicle that includes a chassis, said adjustment device comprising:

a lower rail configured to be fixed to the chassis, inside which lower rail is an upper rail, to which a seat is attached, and adapted to be propelled by a motor;

a spindle inside the upper rail and having its respective ends fixed to the lower rail, a transmission fixedly coupled to the upper rail is arranged in axially movable fashion, wherein the transmission is clampingly held in the upper rail and has a transmission housing whose opposite housing walls lie between wall parts of the upper rail and whose upper wall projects from the upper rail, where the transmission is held in the upper rail by metal stirrups bent into an L-shape made oppositely in a recess in the upper rail, between which stirrups of the transmission housing is slipped with wall tapers.

6. A longitudinal seat adjustment device for use in a motor vehicle that includes a chassis, said adjustment device comprising:

a lower rail configured to be fixed to the chassis, inside which lower rail is an upper rail, to which a seat is attached, and adapted to be propelled by a motor; and

a spindle inside the upper rail and having its respective ends fixed to the lower rail, a transmission fixedly coupled to the upper rail is arranged in axially movable fashion, wherein the transmission is clampingly held in the upper rail and has a transmission housing whose opposite housing walls lie between wall parts of the upper rail and whose upper wall projects from the upper rail, where the transmission has a spindle nut resting on the spindle with worm gear and a worm engaging with the worm gear, and a thrust ring is integrally molded onto the spindle nut.

7. The device according to claim 6 , where the spindle nut and the thrust ring are made of metal.

8. The device according to claim 7 , where the worm gear is coaxially applied to the spindle nut by plastic injection.