Actuator

Abstract

An actuator, in particular a valve drive, has an outer housing with a first housing part and an adjoining second housing part, wherein in the interior of the outer housing a drivable piston is provided. The running surface of the piston in the first housing part is defined by a formed portion of the first housing part. The circular cylindrical shape of the running surface is guaranteed in that the first housing part is mounted onto a circumferential centering collar of the second housing part.

1 . An actuator, comprising an outer housing which includes at least one first housing part and one second housing part, which adjoins and is attached to the first housing part, wherein the first housing part has an inner side with a running surface for a hydraulically or pneumatically drivable piston coupled with a valve tappet, wherein the first housing part is a metallic formed part having a circumferential rim which with its circumferential rim is mounted onto the outside of a circumferential centering collar at the second housing part. 
     
     
         2 . The actuator according to  claim 1 , wherein the second housing part is a cast part. 
     
     
         3 . The actuator according to  claim 1 , wherein the first housing part has a circumferential wall which terminates with the circumferential rim and which has a smaller radial bending stiffness than the second housing part in the region of the centering collar. 
     
     
         4 . The actuator according to  claim 1 , wherein the running surface is a surface unmachined after forming of the first housing part. 
     
     
         5 . The actuator according to  claim 1 , wherein the region adjoining the circumferential rim is flared all around, wherein the flare amounts to between 0.01 and 20% of the outside diameter of the first housing part in the region of the running surface. 
     
     
         6 . The actuator according to  claim 5 , wherein the flare amounts to between 1 and 4% of the outside diameter of the first housing part in the region of the running surface. 
     
     
         7 . The actuator according to  claim 1 , wherein the second housing part has an axial stop for the circumferential rim. 
     
     
         8 . The actuator according to  claim 1 , wherein the first housing part sits on the centering collar without clearance. 
     
     
         9 . The actuator according to  claim 1 , wherein the first housing part sits on the centering collar without clearance by means of a press fit. 
     
     
         10 . The actuator according to  claim 1 , wherein the first housing part and the second housing part are welded, soldered or glued to each other. 
     
     
         11 . The actuator according to  claim 1 , wherein the second housing part has a guiding dome for the valve tappet extending into the housing interior as well as a stop for the piston. 
     
     
         12 . The actuator according to  claim 1 , wherein the stop for the piston is formed by the end face of the guiding dome. 
     
     
         13 . The actuator according to  claim 1 , wherein the first housing part is a deep drawn or internal high-pressure formed part. 
     
     
         14 . The actuator according to  claim 1 , wherein the first housing part is pot-shaped and the second housing part is arranged closer to the associated valve seat than the first housing part. 
     
     
         15 . The actuator according to  claim 1 , wherein the first housing part has a continuously constant wall thickness and/or the second housing part has a non-uniform wall thickness. 
     
     
         16 . The actuator according to  claim 1 , wherein the outer housing is a two-part housing.