Medical tube, catheter, and method for producing medical tube

A catheter assembly comprising:

• a catheter in combination with a driveshaft that is positionable in the catheter;
• the driveshaft comprising:
• an elongated shaft;
• a housing fixed to a distal end portion of the shaft;
• and an ultrasonic vibrator stored in the housing;
• the catheter comprising:
• an elongated first tube having a longitudinal extent and possessing a proximal end and a distal end, the first tube possessing a first portion, a second portion and a third portion arranged in this order in a longitudinal direction from a proximal end side toward a distal end side of the tube, the tube being made of resin;
• the first portion, the second portion and the third portion each possessing an inner diameter and an outer diameter;
• the outer diameter of the first portion being greater than the outer diameter of the second portion, and the inner diameter of the second portion being substantially equal to the inner diameter of the first portion;
• the inner diameter of the third portion being smaller than the inner diameter of the second portion, and the outer diameter of the third portion being smaller than the outer diameter of the second portion;
• the outer diameter of the third portion and the inner diameter of the second portion being substantially equal;
• and
• the entire longitudinal extent of the first portion, the entire longitudinal extent of the second portion and the entire longitudinal extent of the third portion being formed only of a single resin;
• a second tube in contact with and covering both the entire longitudinal extent of the outer surface of the second portion of the first tube and the entire longitudinal extent of the outer surface of the third portion of the first tube;
• the second tube not covering the outer surface of the proximal end part of the first portion;
• the second tube possessing a distal end portion that extends distally beyond a distal-most end of the third portion of the first tube;
• a third tube that possesses a proximal end portion positioned between a portion of the second tube of the first tube and a portion of the third portion of the first tube so that an outer surface of the proximal end portion of the third tube faces an inner surface of the portion of the second tube and an inner surface of the proximal end portion of the third tube faces the outer surface of portion of the third portion of the first tube;
• the third tube extending distally beyond a distal-most end of the second tube and extending distally beyond a distal-most end of the first tube;
• and
• the second tube extending distally beyond a distal-most end of the first tube.