Turbomachine for an aircraft

A turbomachine for an aircraft, the turbomachine extending along a longitudinal axis and comprising:

• a low-pressure compressor comprising a compressor rotor,
• a low-pressure shaft configured to drive the compressor rotor, the low-pressure shaft being centered on the longitudinal axis and having an internal passage configured for the circulation of a first air stream along the longitudinal axis from upstream to downstream, the low-pressure shaft comprising:
• a first cylindrical segment,
• a second segment secured in rotation to the first segment and arranged upstream of the first segment, the second segment comprising a first frustoconical portion connected to the compressor rotor,
• an intermediate casing arranged around the first segment and downstream of the low-pressure compressor,
• at least one bearing configured to guide the low-pressure shaft in rotation, arranged radially between the first segment and the intermediate casing,
• an annular intermediate lubrication chamber wherein said at least one bearing is arranged, the intermediate lubrication chamber being arranged in the intermediate casing,
• an annular air chamber configured to be supplied with air from the low-pressure compressor, the air chamber being delimited axially, at least in part, by the first frustoconical portion and a radial separating wall mounted around the first segment, the first frustoconical portion also having at least one opening putting the air chamber into communication with the internal passage to allow the first air stream to pass from the air chamber to the internal passage.