Trailer coupling having a ball neck and a coupling ball, and method for production thereof

Abstract

The invention relates to a trailer coupling for a motor vehicle, wherein the trailer coupling has a coupling arm, on the free end region of which a ball neck is formed, on which a coupling ball is arranged for attaching a trailer or coupling a load carrier to the motor vehicle. The coupling ball is spherical on the side thereof facing away from the ball neck and has a spherical segment plane on the side thereof facing the ball neck. Between the spherical segment plane and a portion of the ball neck which has a smaller outer circumference than the spherical segment plane there is arranged a throat portion having a transition contour extending in a concave manner between the ball neck and the spherical segment. The transition contour transitions with a coupling ball transition region into an external contour of the coupling ball, in particular into the spherical segment plane, and transitions with a ball neck transition region into an outer surface of the ball neck. According to the invention, the transition contour has a curved configuration having a non-constant radius.

1 . A trailer coupling for a motor vehicle, wherein the trailer coupling comprises a coupling arm, on a free end region of which a ball neck is formed, on which a coupling ball is arranged for attaching a trailer or coupling a load carrier to the motor vehicle, wherein the coupling ball is spherical on a side thereof facing away from the ball neck and has a spherical segment plane on the side thereof facing the ball neck, wherein between the spherical segment plane and a portion of the ball neck which has a smaller outer circumference than the spherical segment plane there is arranged a throat portion having a transition contour extending in a concave manner between the ball neck and the spherical segment plane, the transition contour transitioning with a coupling ball transition region into an external contour of the coupling ball, and transitioning with a ball neck transition region into an outer surface of the ball neck, wherein the transition contour has a curved configuration with a non-constant radius and/or with at least two radii that differ from one another. 
     
     
         2 . The trailer coupling according to  claim 1 , wherein the transition contour in the coupling ball transition region, and/or in the ball neck transition region, has a larger radius or a plurality of larger radii than in an intermediate region between the transition regions. 
     
     
         3 . The trailer coupling according to  claim 1 , wherein the transition contour at a number of points that differ from one another has a number of radii that differ from one another and/or is designed as a spline contour. 
     
     
         4 . The trailer coupling according to  claim 1 , wherein the transition contour at all points along its course or substantially and/or in the ball neck transition region and/or the coupling ball transition region is continuously differentiable at least once. 
     
     
         5 . The trailer coupling according to  claim 1 , wherein the transition contour transitions tangentially or without an angle or at an angle of 0 degrees or 180 degrees into the spherical segment plane and/or the ball neck. 
     
     
         6 . The trailer coupling according to  claim 1 , wherein the transition contour has at least two curved portions with curvatures in opposite directions. 
     
     
         7 . The trailer coupling according to  claim 1 , wherein the transition contour has one portion running in a S-shape. 
     
     
         8 . The trailer coupling according to  claim 1 , wherein the transition contour has a waisting between the transition regions. 
     
     
         9 . The trailer coupling according to  claim 1 , wherein the throat portion has at least one outer circumference, which is smaller than an outer circumference of the ball neck. 
     
     
         10 . The trailer coupling according to  claim 1 , wherein the ball neck has a rounded waisting or in that the transition contour extends as far as a minimum outer circumference of the ball neck. 
     
     
         11 . The trailer coupling according to  claim 1 , wherein the ball neck is arranged on an end region of an arm body, the other end region of which is designed and provided for connection with the motor vehicle. 
     
     
         12 . The trailer coupling according to  claim 11 , wherein the arm body has at least one bend and/or one curved portion for matching to a bodywork contour or bumper contour of the motor vehicle and/or in that the arm body has a substantially non-circular cross section and/or in that the arm body at least directly next to the ball neck has a larger cross-sectional area than the ball neck. 
     
     
         13 . The trailer coupling according to  claim 1 , wherein the ball neck close to the throat portion has a smaller outer circumference than in a region remote from the throat portion. 
     
     
         14 . The trailer coupling according to  claim 1 , wherein the shell surface of the ball neck directly next to the throat portion is configured as a cylinder surface of a circular cylinder. 
     
     
         15 . The trailer coupling according to  claim 1 , wherein the ball neck is designed entirely or substantially as a circular cylinder. 
     
     
         16 . The trailer coupling according to  claim 1 , wherein the spherical segment plane a ring surface area is provided, the external diameter of which adjoins the spherical ball surface of the coupling ball and the internal diameter or inner circumference of which adjoins the coupling ball transition region or transitions into the coupling ball transition region. 
     
     
         17 . The trailer coupling according to  claim 1 , wherein in the spherical segment plane a flat surface is provided or present. 
     
     
         18 . The trailer coupling according to  claim 1 , wherein the coupling ball transition region has a recess extending behind the spherical segment plane away from the ball neck. 
     
     
         19 . The trailer coupling according to  claim 1 , wherein the coupling ball in its region facing away from the ball neck has a flat surface running parallel to the spherical segment plane. 
     
     
         20 . The trailer coupling according to  claim 1 , wherein the coupling ball is a spherical segment ball, which in g region facing away from the ball neck and a region facing the ball neck in each case has a flattened area. 
     
     
         21 . The trailer coupling according to  claim 1 , wherein the coupling ball and/or the ball neck and/or the throat portion are produced by deformation. 
     
     
         22 . The trailer coupling according to  claim 1 , wherein the basic material of the throat portion has a microstructure with substantially or exclusively uninterrupted or intact fibre flows. 
     
     
         23 . The trailer coupling according to  claim 1 , wherein the spherical segment plane is at right-angles to a longitudinal axis of the ball neck. 
     
     
         24 . The trailer coupling according to  claim 1 , wherein the transition contour has a curved configuration with precisely two, three or four radii that differ from one another. 
     
     
         25 . The method for producing a trailer coupling for a motor vehicle, wherein the trailer coupling has comprises a coupling arm, on the free end region of which a ball neck is formed, on which a coupling ball is arranged for attaching a trailer or coupling a load carrier to the motor vehicle, wherein the coupling ball is spherical on the side thereof facing away from the ball neck and has a spherical segment plane on the side thereof facing the ball neck, wherein between the spherical segment plane and a portion of the ball neck which has a smaller outer circumference than the spherical segment plane there is arranged a throat portion having a transition contour extending in a concave manner between the ball neck and the spherical segment plane, the transition contour transitioning with a coupling ball transition region into an external contour of the coupling ball, and transitioning with a ball neck transition region into an outer surface of the ball neck, wherein by cutting by machining and/or deformation of a blank to form the throat portion such that the transition contour has a curved configuration with a non-constant radius. 
     
     
         26 . The method according to  claim 25 , wherein during the deformation of a microstructure of the blank, in the region of the throat portion, is completely or substantially deformed and not interrupted.