Guide ring of a pump element of a vehicle brake system

The guide ring structure (48) has a center area that is extended along a longitudinal direction. A radial force is applied in a resilient edge area. The elasticity of the resilient edge area is set higher than the elasticity of the center area. A V-shaped notch is located at a front side of the resilient edge area. The edge area is provided with a sealing lip portion which is arranged opposite to a piston (18).