Actuator with Position Sensing Device

Abstract

The invention relates to an actuator, in particular pneumatic cylinder, with an actuator element movably located in a movement space of a housing and with a microwave position sensing device for detecting the position of the actuator element in the movement space, with a microwave aerial arrangement for the transmission of microwaves into the movement space forming a waveguide and for the reception of reflection microwaves generated by the reflection of the transmitted microwaves at the actuator element from the movement space, and with evaluation means for the generation of a position signal representing the current position of the actuator element from the reflection microwaves. In the actuator, it is provided that the actuator element has a groove arrangement with at least one groove for reflecting the microwaves.

1 . An actuator comprising:
 a pneumatic cylinder;   an actuator element movably located in a movement space of a housing;   a microwave position sensing device for detecting the position of the actuator element in the movement space,   a microwave aerial arrangement for the transmission of microwaves into the movement space forming a waveguide and for the reception of reflection microwaves generated by the reflection of the transmitted microwaves at the actuator element from the movement space; and   evaluation means for the generation of a position signal representing the current position of the actuator element from the reflection microwaves, the actuator element having a groove arrangement with at least one groove for reflecting the microwaves.   
   
   
       2 . The actuator according to  claim 1 , wherein the waveguide acts as an outer conductor of a coaxial line for the microwaves and the groove arrangement is located on an inner conductor section of the coaxial line, the groove arrangement at least partially preventing a current flow along the inner conductor section and thus acting as a reflection body. 
   
   
       3 . The actuator according to  claim 1  wherein the groove arrangement is located on an outer circumference of the actuator element. 
   
   
       4 . The actuator according to  claim 1  wherein the groove arrangement is located on a recess of the actuator element. 
   
   
       5 . The actuator according to  claim 1  wherein the groove arrangement is located on a projection of the actuator element. 
   
   
       6 . The actuator according to  claim 5 , wherein a recess of the actuator element or the projection forms a part of a cushion arrangement for reducing the end speed of the actuator element in the region of an end stop of the housing. 
   
   
       7 . The actuator according to  claim 1  wherein the groove arrangement has a recess or is located on a recess into which a projection on the housing can dip. 
   
   
       8 . The actuator according to  claim 3  wherein the groove arrangement is provided on the entire outer circumference or at least on a segment of the circumference of the actuator element or of the projection of the actuator element or on the entire inner circumference or at least on a segment of the inner circumference of a recess of the actuator element. 
   
   
       9 . The actuator according to  claim 1  wherein the groove arrangement and the microwave aerial arrangement are coaxial. 
   
   
       10 . The actuator according to  claim 1  wherein the at least one groove has a rectangular internal contour. 
   
   
       11 . The actuator according to  claim 1  wherein the at least one groove is hollow or filled with a dielectric material. 
   
   
       12 . The actuator according to  claim 1  wherein the at least one groove has a depth corresponding to approximately a quarter of the wavelength of the microwaves spreading in the region of the interior space of the at least one groove. 
   
   
       13 . The actuator according to  claim 12 , wherein the interior space is filled with a dielectric material and the depth of the at least one groove is less than a quarter of the wavelength of the microwaves with reference to air as propagation medium. 
   
   
       14 . The actuator according to  claim 1  wherein the spacing of the grooves of the groove arrangement is less than the depth of the respective grooves. 
   
   
       15 . The actuator according to  claim 1  wherein the groove arrangement forms or includes a holder for at least one further component of the actuator element, in particular for a seal arrangement and/or for a guide device for guiding the actuator element in the movement space. 
   
   
       16 . The actuator according to  claim 1  the actuator element comprises an actuator body, in particular a plastic actuator body, on which the groove arrangement is located. 
   
   
       17 . The actuator according to  claim 1  the groove arrangement is located on an electrically conductive groove component provided on the actuator body. 
   
   
       18 . The actuator according to  claim 1  wherein the groove arrangement includes an electrically conductive coating provided on the actuator element. 
   
   
       19 . The actuator according to  claim 1  wherein the actuator it is a rodless pneumatic operating cylinder or a pneumatic operating cylinder with a piston rod. 
   
   
       20 . The actuator according to  claim 1  wherein the actuator comprises an electric drive or an electric drive component.