Patent ID: 8416041

Claim:
A solenoid comprising: a core having a junction surface; a plunger assembly including a plunger having a junction surface comprising at least one of: a) a concave facing with a relief at a center thereof; and b) a relief along a periphery thereof, and a plunger pot having a junction surface which comprises a substantially flat or convex conical facing, the junction surfaces meeting at an interface within the plunger assembly and having a gap formed between the substantially flat or convex conical facing and concave facing; a shading ring located proximate to the interface between the junction surfaces, the shading ring having an outside diameter slightly smaller than the diameter of the core and operable to produce a concentration of magnetic attraction at the interface between the plunger junction surface and the plunger pot junction surface within an annular range of the interface between a center of the interface and a radial position on the interface adjacent to the shading ring, wherein a contact region between the plunger junction surface and the plunger pot junction surface is substantially smaller than the respective junction surfaces and located proximate to the annular range of the concentration of magnetic attraction.