Butterfly valve having overmolded axle

摘要

A flap shaft (4) is attached to an area (3) of a thin punched metal insert (1) and the assembly placed in a molding tool. A housing (17) is then injection molded onto and around the edge (7) of the punched insert. During injection of the housing plastic flows around the shaft in the attachment area to lock shaft and punched insert together. A flat area (2) of the punched insert is then cut out. A flap shaft (4) is attached to an area (3) of a thin punched metal insert (1) and the assembly placed in a molding tool. A housing (17) is then injection molded onto and around the edge (7) of the punched insert. During injection of plastic onto the punched insert (1) to form a housing (17) the plastic penetrates through openings (8) in the edge of the punched insert and also openings (6,13) in the flat area (2) of the latter and shaft (4). Plastic passing through the openings (6) forms ribs (21). Injected plastic also flows into free spaces around loop-shaped punched out sections alternately formed on the upper and lower sides of the insert flat area. Bearing bushes (19,20) are pressed onto the shaft in the area of cut-outs in the edge of the insert after injection is completed. A laser cuts out the flat area of the punched insert along a weak zone (16). An Independent claim is included for a throttle flap unit comprising a punched insert (1) with a weak zone bordering a flat area to be cut out. The weak zone may be formed on either one or both sides of the insert.