Perfected device for setting synchronizing rings of a turbojet compressor

Abstract

A device is dedicated to setting one or more pivoting axial flow synchronizing rings (R), comprising a drive mechanism ( 4 - 6 ) intended to rotate their rotary spindle ( 3 ) so as to set them angularly depending on angular position data supplied by a means of control. These means of control comprise firstly means of illumination ( 8, 10 ) designed to supply light to an illumination zone ( 11 ), secondly an encoder element ( 12 ) attached to the spindle of the synchronizing ring (R) in the illumination zone ( 11 ) and designed to interact with the illumination light in order to generate optical signals representing the angular position of the synchronizing ring, thirdly means ( 13 a ) designed to collect the optical signals and fourthly means of processing ( 7 ) designed to determine angular position data based on the optical signals collected.

1 . Device for setting pivoting axial flow synchronizing ring(s) (R) for a turbojet compressor (CHP), comprising a drive mechanism ( 4 - 6 ) suitable for driving in rotation at least one synchronizing ring (R) spindle ( 3 ) so as to set it angularly depending on position data supplied by means of control ( 7 - 26 ), characterised in that said means of control comprise means of illumination ( 8 ,  10 ) capable of supplying light to the illumination zone ( 11 ), an encoder element ( 12 ) attached to the synchronizing ring spindle ( 3 ) in said illumination zone and designed in such a way as to interact with said light to generate optical signals representing the angular position of said synchronizing ring (R), means of collection ( 13 ) of said optical signals and means of processing ( 7 ) designed to determine angular position data based on said optical signals collected.  
   
   
       2 . Device according to  claim 1 , characterised in that said encoder element ( 12 ) is implemented in the form of at least one encoder wheel portion having at least one scale ( 15 ) configured in order to permit the generation of variable optical signals depending on its position in said illumination zone ( 11 ).  
   
   
       3 . Device according to any one of  claim 1  and  2 , characterised in that said light source ( 8 ,  10 ) comprises at least one optical fibre ( 10 ) having an extremity configured so as to light up said illumination zone ( 11 ) over a surface of selected dimensions.  
   
   
       4 . Device according to any one of claims  2  and  3 , characterised in that said scale ( 15 ) comprises at least one slot ( 17 ,  18 ) configured so as to transmit the light differently depending on the angular position of said encoder element ( 12 ).  
   
   
       5 . Device according to  claim 4 , characterised in that said slot ( 17 ) has a progressive opening.  
   
   
       6 . Device according to  claim 4 , characterised in that said scale ( 15 ) comprises a plurality of slots ( 18 ) of various shapes and/or spaced from one another at a variable distance.  
   
   
       7 . Device according to any one of claims  2  and  3 , characterised in that said scale is transparent and consists of at least one zone equipped with markings ( 21 ).  
   
   
       8 . Device according to  claim 7 , characterised in that it comprises a transparent scanning reticle ( 25 ) interposed between the illumination light and said encoder element ( 12 ) and in that said means of collection ( 13 ) comprise photodetectors ( 13   b ) positioned facing said scale ( 15 ) on the side opposite said illumination zone ( 11 ) and capable of supplying electrical signals representing optical signals resulting from the interaction between the illumination light, said scanning reticle ( 25 ) and said markings ( 21 ).  
   
   
       9 . Device according to any one of  claims 4  to  7 , characterised in that said means of collection ( 13 ) comprise photodetectors ( 13   b ) positioned facing said scale ( 15 ) on the side opposite said illumination zone ( 11 ) and capable of supplying electrical signals representing optical signals transmitted to the scale.  
   
   
       10 . Device according to any one of  claims 4  to  7 , characterised in that said means of collection ( 13 ) comprise at least one optical fibre ( 13   a ) having an extremity configured so as to collect said optical signals transmitted to said scale ( 15 ).  
   
   
       11 . Device according to any one of claims  2  and  3 , characterised in that said scale ( 15 ) comprises at least one reflecting element ( 16 ) configured in such a way as to reflect said light differently according to the angular position of said encoder element ( 12 ).  
   
   
       12 . Device according to  claim 11 , characterised in that it comprises a transparent scanning reticle interposed between said illumination light and said encoder element ( 12 ) and defining a transparent phase grating, whereby said reflecting element comprises markings and whereby said means of collection ( 13 ) comprise photodetectors positioned upstream of said scanning reticle and capable of supplying electrical signals representing optical signals resulting from the interaction between the illumination light, said scanning reticle and said markings.  
   
   
       13 . Device according to  claim 11 , characterised in that said means of collection ( 13 ) comprise at least one optical fibre ( 13   a ) having an extremity configured so as to collect said optical signals reflected to said scale ( 15 ).  
   
   
       14 . Device according to any one of  claims 1  to  13 , characterised in that one section at least of the encoder element ( 12 ), one section of said light source ( 10 ) and one section at least of said means of collection ( 13   a ,  13   b ) are accommodated in a chamber ( 14 ) sealed against light.  
   
   
       15 . Device according to any one of  claims 1  to  14 , characterised in that said means of processing ( 7 ) is accommodated in a casing ( 9 ) remote from said synchronizing ring (R).  
   
   
       16 . Device according to any one of the above claims, characterised in that said drive mechanism ( 4 - 6 ) comprises a ring ( 5 ) attached by a plurality of links ( 4 ) to a plurality of synchronizing rings (R) and a ram ( 6 ) capable of adjusting said ring ( 5 ) so as to set said plurality of synchronizing rings (R) in angular positions selected according to said angular position data determined by said means of processing ( 7 ).