Power transmission shaft and propeller shaft for vehicle

A power transmission shaft, comprising:

• a shaft member having, on an outer peripheral surface thereof, a male spline;
• a cylindrical member having, on an inner peripheral surface thereof, a female spline that is engaged with the male spline;
• a length adjusting portion that adjusts a length of a spline-engagement of the male and female splines in an axial direction;
• a seal member having a sealing effect, the seal member provided in a pressed state between an outer peripheral seal surface formed on the outer peripheral surface of the shaft member and an inner peripheral seal surface formed on the inner peripheral surface of the cylindrical member;
• a sealing effect removal portion that removes the sealing effect of the seal member when the length is adjusted by the length adjusting portion;
• and
• a retaining pin, one side of which is engaged with one engaging hole formed at the shaft member, and another side of which is engaged with another engaging hole formed at the cylindrical member,
• wherein the engaging holes are respectively positioned between a spline forming portion where splines of the shaft member and the cylindrical member are formed and the seal surfaces of the shaft member and the cylindrical member.

A propeller shaft for a vehicle comprising:

• a cylindrical member whose one end side is connected to the vehicle through a first joint member, the cylindrical member having, on an inner peripheral surface thereof, a female spline;
• a shaft member whose second end side is connected to the vehicle through a second joint member, the shaft member having, on an outer peripheral surface thereof, a male spline that is engaged with the female spline, the cylindrical member and the shaft member being spline-engaged with each other by a first end side of the shaft member being inserted into the cylindrical member, and a length of the spline-engagement being adjusted by sliding of the splines in an axial direction in response to an input from a direction of the first or second joint member;
• and
• a seal member provided in a pressed state with a predetermined tightness between an outer peripheral seal surface formed on the outer peripheral surface of the shaft member and an inner peripheral seal surface formed on the inner peripheral surface of the cylindrical member, wherein:
• when the splines relatively slide in the axial direction, the seal member contacting at least one of the inner or outer peripheral seal surfaces with a smaller tightness than the predetermined tightness,
• the seal member is a ring-shaped seal ring,
• the shaft member has, from the first end side of the shaft member:
• a large diameter male spline forming portion where the male spline is formed;
• a middle diameter portion whose diameter is smaller than that of the male spline forming portion;
• and
• a small diameter portion whose diameter is smaller than that of the middle diameter portion,
• the outer peripheral seal surface is formed on the middle diameter portion, and
• when the splines relatively slide in the axial direction, the seal member contacts the small diameter portion.

A power transmission shaft comprising:

• a shaft member having, on an outer peripheral surface thereof, a male spline;
• a cylindrical member having, on an inner peripheral surface thereof, a female spline, the cylindrical member being spline-engaged with the shaft member by a first end side of the shaft member being inserted into the cylindrical member from an end side of the cylindrical member, and an axial direction shock being absorbed by sliding of the splines;
• and
• a seal member provided in a pressed state between an outer peripheral seal surface formed on the outer peripheral surface of the shaft member and an inner peripheral seal surface formed on the inner peripheral surface of the cylindrical member, wherein:
• the outer peripheral seal surface is positioned at a second end side of the shaft member with respect to the male spline,
• the inner peripheral seal surface is positioned at the end side of the cylindrical member with respect to the female spline,
• the shaft member is provided, at the second end side with respect to the male spline on the outer peripheral surface thereof, with a non-seal surface whose diameter is smaller than that of the outer peripheral seal surface,
• the seal member is a ring-shaped seal ring,
• the shaft member has, from the first end side of the shaft member:
• a large diameter male spline forming portion where the male spline is formed;
• a middle diameter surface whose diameter is smaller than that of the male spline forming portion;
• and
• a small diameter surface whose diameter is smaller than that of the middle diameter surface, and
• the outer peripheral seal surface is formed on the middle diameter surface, and the non-seal surface is formed on the small diameter surface.

A power transmission shaft, comprising:

• a shaft member having, on an outer peripheral surface thereof, a male spline;
• a cylindrical member having, on an inner peripheral surface thereof, a female spline that is engaged with the male spline;
• a length adjusting portion that adjusts a length of a spline-engagement of the male and female splines in an axial direction;
• a seal member having a sealing effect, the seal member provided in a pressed state between an outer peripheral seal surface formed on the outer peripheral surface of the shaft member and an inner peripheral seal surface formed on the inner peripheral surface of the cylindrical member;
• and
• a sealing effect removal portion that removes the sealing effect of the seal member when the length is adjusted by the length adjusting portion, wherein:
• the seal member is a ring-shaped seal ring,
• the shaft member has, from one end side of the shaft member:
• a large diameter male spline forming portion where the male spline is formed;
• a middle diameter surface whose diameter is smaller than that of the male spline forming portion;
• and
• a small diameter surface whose diameter is smaller than that of the middle diameter surface, and
• the outer peripheral seal surface is formed on the middle diameter surface, and the non-seal surface is formed on the small diameter surface.