Reduction gear unit

A bearing unit with a reduction gear, comprising:

• an outer ring having an inside circumferential surface provided with at least one outer ring raceway;
• an inner ring having an end face and comprising a first inner ring section and a second inner ring section so as to have an outside circumferential surface provided with at least one inner ring raceway opposed to the outer ring raceway;
• a plurality of rolling bodies provided between the outer ring raceway and the inner ring raceway;
• a plurality of support shafts provided parallel to the outer and inner rings and each having a base portion connected to the end face of the inner ring;
• a plurality of planetary gears located around each of the support shafts;
• a ring gear provided in an interlocking relationship with the planetary gears;
• wherein the first inner ring section has a larger diameter section having an outside circumferential surface formed with an inner ring raceway, and a smaller diameter section positioned axially adjacent to the larger diameter section, and wherein
• the second inner ring section is fitted around the smaller diameter section of the first inner ring section in a spline-engagement relationship.