Regarding the improvement or originality of the internal structure of the machine, you can apply for utility model and invention patent.
If you apply for a utility model, the authorization time is relatively short, and you can get the certificate in almost one year, but the stability of the patent is very poor.
If you apply for an invention patent, the authorization time is very long, and it takes three years to get the certificate, but the patent is stable.
You can also apply for two patents at the same time. I suggest you consult the local patent agency.
You can email me and I will send you the application process.
linxiaobing@jily.cn