Inventors on patent regarding research results

In our research institute, advisors give phd students a lot of freedom and sometimes are not so much involved in the research. This was also the case for my latest research project. I gave him some demos every now and then to show my progress and another phd student helped me out a bit with making some examples and nice figures. However, I came up with the initial idea and step by step made the necessary decissions to come to the point where we are now. We are now in a phase where my advisor and the university want to patent my research and we are discussing all the possibilities with people from the legal departement. However, in all documents the other phd student + my advisor are also mentioned as "inventors". Wheras I'm quite sure that according to the laws related to being an inventor on a patent, they are officially not an inventor of this research project. The research that I did is quite applied so there is some chance that we can make some money with it in the future (selling it or starting a company). The university states that the inventors get 30% of all the profit that comes from the patent. This means that I would only get 10% since we are with 3 co-inventers. Also when I would start a company that does something with these results I would still have to give them some of the profit whereas they did not do something significant in the end.

When I look at researchers at other universities, I notice that it is quite common that all the authors on a paper are also the inventors of the patent that is associated with it. I can imagine that for most of these cases all the people involved at some innovative contribution which makes them a legitimate inventor. On the other hand it is also quite hard to say to your advisor that they should not be an inventor on the patent...

Is this an unspoken rule at many universities that advisors and co-workers are also inventors on a patent (similar to authors on a paper)? Is someone having experience a similar situation? How should I bring this up to my advisor and co-worker or would it bring me into more trouble when I would start this discussion?