The following sound like the same thing and yet, there is a difference. I think.
Technosexual: A person with a sexual attraction to machinery, as in the case of robot fetishism. When used thus, it is a portmanteau word combining “technophile” and “sexual”.
Mechaphilia or Mechanophilia is a paraphilia describing a sexual attraction to machines such as bicycles, motor vehicles, helicopters, and aeroplanes.
The small difference I see between these two terms is that the technosexual is attracted to machinery which can give something back (like the robot which is more like a mechanical being than a mechanical thing). Have you ever seen someone with a fetish for a machine which was not humanized in some way? It’s an interesting topic for thought.
We name mechanical things in our lives, like cars and boats. How much farther is it to be attracted to these named mechanical creations? A bit far for me. There is a difference between having a personal attachment to something versus going that step farther into having a romantic attachment to the same object.