Energy absorbing steering column

An energy absorbing steering column comprising:

• a first cylindrical member accommodating a steering shaft of a vehicle and rotatably supporting the steering shaft about an axis thereof;
• the first cylindrical member including a first front open end and a first rear open end in a front-rear direction of the vehicle, a first enlarged diameter portion formed near the first front open end and a second enlarged diameter portion formed at a predetermined distance in an axial direction of the first cylindrical member from the first front open end;
• a second cylindrical member accommodating the first cylindrical member, normally supporting the first cylindrical member in a predetermined position and allowing the first cylindrical member to axially move relative to the second cylindrical member upon application of a load greater than a predetermined value to the steering shaft;
• the second cylindrical member including a second front open end and a second rear open end in the front-rear direction of the vehicle, a first supporting portion formed on an inner surface of the second cylindrical member at a predetermined distance in an axial direction of the second cylindrical member from the second rear open end, and a second supporting portion formed on the inner surface of the second cylindrical member near the second rear open end;
• an elastic bush provided between the first enlarged diameter portion and the first supporting portion for applying elastic force in a radial direction of the elastic bush and supporting the steering shaft to restrict an axial movement of the first cylindrical member relative to the second cylindrical member;
• the elastic bush being positioned in a recess in the first supporting portion of the second cylindrical member;
• and
• wherein the first cylindrical member includes a reduced diameter portion formed between a position where the second enlarged diameter portion is supported by the second supporting portion and a position near the first rear open end, wherein a part of a circumference of the reduced diameter portion is continuously reduced.