Adapter for an oil filler neck and assembly method for the adapter

1. An adapter for an oil filler neck, wherein the adapter comprises:

an extension piece with a lower partial region and an upper partial region, wherein the lower partial region comprises an outer bayonet cap guide that is adjusted to an inner bayonet cap guide of an oil fill port, and wherein the upper partial region comprises the inner bayonet cap guide that is adjusted to the outer bayonet cap guide of an oil filler inlet cover, and

an outer retaining ferule that comprises an anti-twist device apron, which engages an outer edge region of the oil fill port in a positive and torsionally rigid manner,

wherein the retaining ferule has distributed on its periphery engagement hooks, which can be detachably engaged with the lower partial region if the adapter is engaged with the inner bayonet cap guide of the oil fill port.

2. The adapter according to claim 1 , wherein the upper partial region comprises an axially aligned outer actuator spring that engages an axially aligned inner longitudinal slot of the retaining ferule so as to be torsionally rigid and axially displaceable.

3. The adapter according to claim 1 , wherein the oil filler inlet cover comprises an annular groove that is located between the outer bayonet cap guide and an overhanging oil filler inlet cover cap, and incorporates an annular sealing element that operatively interacts with an inner wall of the upper partial region in a media-tight manner.

4. The adapter according to claim 1 , wherein the lower partial region comprises a flange that hangs over the oil fill port, and is bonded with a corresponding lower flange of the upper partial region.

5. The adapter according to claim 4 , wherein the lower partial region exhibits an annular groove between the overhanging flange and the outer bayonet cap guide, which incorporates an annular sealing element that operatively interacts with an inner wall of the oil filler neck in a media-tight manner.

6. An assembly method for an adapter for an oil filler neck, wherein the method comprises the steps of:

preparing an adapter from an extension piece that has a lower and upper partial region that are bonded together;

brushing a retaining ferule with an anti-twist device apron onto the extension piece of the adapter along an axially aligned actuator spring of the upper partial region, which is arranged in an axially aligned longitudinal slot of the retaining ferule;

axially introducing the lower partial region of the adapter with an outer bayonet cap guide into an inner bayonet cap guide of an oil fill port of the oil filler neck;

turning the extension piece along with the retaining ferule, accompanied by the closure of the bayonet cap between the lower partial region and the oil fill port; and

axially displacing the retaining ferule, with the anti-twist device apron becoming latched in an edge region of the oil filler neck in a form fitting manner.

7. The assembly method according to claim 6 , further comprising undetachably engagement hooks of the retaining ferule with a flange of the lower partial region hanging over the oil inlet port.

8. The assembly method according to claim 6 , further comprising axially introducing the lower partial region of the adapter into the inner bayonet cap guide of the oil fill port of the oil filler neck during which a sealing element in an annular groove of the lower partial region of the adapter establishes a media-tight contact to an inner wall of the filler neck.

9. The assembly method according to claim 6 , wherein an oil filler inlet cover is axially introduced in the upper region, and twisted into the inner bayonet cap guide of the upper partial region while engaging an outer bayonet cap guide of the oil filler inlet cover.

10. An adapter for an oil filler neck, wherein the adapter comprises:

an extension piece with a lower partial region and an upper partial region, wherein the lower partial region comprises an outer bayonet cap guide that is adjusted to an inner bayonet cap guide of an oil fill port, and wherein the upper partial region comprises the inner bayonet cap guide that is adjusted to the outer bayonet cap guide of an oil filler inlet cover, and

an outer retaining ferule that comprises an anti-twist device apron, which engages an outer edge region of the oil fill port in a positive and torsionally rigid manner,

wherein the upper partial region comprises an axially aligned outer actuator spring that engages an axially aligned inner longitudinal slot of the retaining ferule so as to be torsionally rigid and axially displaceable.