Portuguese to English Tech/Engineering Patents Petroleum Industry

Hello everyone,

I am having a hard time understanding what the author of this patent means by the above phrase. It seems the "X" means something other than "X", but I can't quite understand how to translate and interpret it.

Please see following sentences for context:

Como a concepção das caixas de engrenagens visam a economia de , é normal encontrar no interior dessas caixas de engrenagens estruturas de reforço estrutural.

Here is another sentence that has the same phrase:

Estas conformações geralmente visam a economia de do invólucro que irá acomodar o conjunto redutor.

Thank you for any help you can provide.

Laura