An assembly, comprising: one circular disk; one ring assembly; and one elastomer ring; wherein the ring assembly exhibits a disk holder that is enclosed by a circumferential shell surface, wherein the shell surface exhibits a ring-shaped circumferential external groove that is limited in a first axial direction by a first outer shoulder and limited in an opposite, second axial direction by a second axial outer shoulder; wherein a guide surface connects to the first outer shoulder in the first axial direction and the radius of this guide surface increases as it gets further away from the first shoulder, wherein dr/dz <2/3 and in particular dr/dz < 1/3 applies, wherein r represents the radius and z represents the axial coordinate of the guide surface in cylindrical coordinates; wherein the circular disk exhibits an outer shell surface area with a circumferential internal groove that extends radially inwards and that is limited in the first axial direction by a first inner shoulder and limited in the second axial direction by a second inner shoulder; wherein at least the two inner shoulders (172, 174) exhibit a convex contour in an axial longitudinal section, in which the rotary axis of the circular disk runs, wherein the elastomer ring is clamped between the two inner shoulders (172, 174) and the two outer shoulders (132, 134), which in particular prevents any movement of the circular disk out of the ring assembly up to a load limit, wherein the elastomer ring acts as a sealing ring. one circular disk; one ring assembly; and one elastomer ring; wherein the ring assembly exhibits a disk holder that is enclosed by a circumferential shell surface, wherein the shell surface exhibits a ring-shaped circumferential external groove that is limited in a first axial direction by a first outer shoulder and limited in an opposite, second axial direction by a second axial outer shoulder; wherein a guide surface connects to the first outer shoulder in the first axial direction and the radius of this guide surface increases as it gets further away from the first shoulder, wherein dr/dz <2/3 and in particular dr/dz < 1/3 applies, wherein the ring assembly exhibits a disk holder that is enclosed by a circumferential shell surface, wherein the shell surface exhibits a ring-shaped circumferential external groove that is limited in a first axial direction by a first outer shoulder and limited in an opposite, second axial direction by a second axial outer shoulder; wherein a guide surface connects to the first outer shoulder in the first axial direction and the radius of this guide surface increases as it gets further away from the first shoulder, wherein dr/dz <2/3 and in particular dr/dz < 1/3 applies, wherein r represents the radius and z represents the axial coordinate of the guide surface in cylindrical coordinates; wherein the circular disk exhibits an outer shell surface area with a circumferential internal groove that extends radially inwards and that is limited in the first axial direction by a first inner shoulder and limited in the second axial direction by a second inner shoulder; wherein at least the two inner shoulders (172, 174) exhibit a convex contour in an axial longitudinal section, in which the rotary axis of the circular disk runs, wherein the elastomer ring is clamped between the two inner shoulders (172, 174) and the two outer shoulders (132, 134), which in particular prevents any movement of the circular disk out of the ring assembly up to a load limit, wherein the elastomer ring acts as a sealing ring. wherein the circular disk exhibits an outer shell surface area with a circumferential internal groove that extends radially inwards and that is limited in the first axial direction by a first inner shoulder and limited in the second axial direction by a second inner shoulder; wherein at least the two inner shoulders (172, 174) exhibit a convex contour in an axial longitudinal section, in which the rotary axis of the circular disk runs, wherein the elastomer ring is clamped between the two inner shoulders (172, 174) and the two outer shoulders (132, 134), which in particular prevents any movement of the circular disk out of the ring assembly up to a load limit, wherein the elastomer ring acts as a sealing ring.