Constant velocity joint
In a constant velocity joint, a center locus of a first ball rolling on a first outer central portion is inclined such that a distance from a central axis of an outer joint member decreases toward a bottom side of the outer joint member. A center locus of a second ball rolling on a second outer central portion is formed in a linear shape and inclined such that a distance from the central axis of the outer joint member increases toward the bottom side of the outer joint member. A center locus of the second ball rolling on the second outer bottom side portion is formed in an arc shape and disposed in the outer joint member at a position radially inwardly from a tangent at a connecting position between the second outer central portion and the second outer bottom side portion.
1. A joint-center-fixed constant velocity joint configured to be provided in a vehicle, the constant velocity joint comprising:
an outer joint member having a bottomed tubular shape opened on one side in an axial direction, the outer joint member including an inner peripheral surface having a first outer ball groove and a second outer ball groove;
an inner joint member placed inwardly from the outer joint member and including an outer peripheral surface having a first inner ball groove corresponding to the first outer ball groove and a second inner ball groove corresponding to the second outer ball groove;
a first ball placed between the first outer ball groove and the first inner ball groove;
a second ball placed between the second outer ball groove and the second inner ball groove; and
a cage placed between the inner peripheral surface of the outer joint member and the outer peripheral surface of the inner joint member, the cage including a plurality of window portions in each of which a corresponding one of the first ball and the second ball is accommodated, wherein
the first outer ball groove includes a first outer central portion provided in a range including a joint center in a central-axis direction of the outer joint member,
a center locus of the first ball rolling on the first outer central portion is inclined such that a distance from a central axis of the outer joint member decreases toward a bottom side of the outer joint member,
the second outer ball groove includes
a second outer central portion provided in a range including the joint center in the central-axis direction of the outer joint member, and
a second outer bottom side portion provided closer to the bottom side of the outer joint member than the second outer central portion is,
a center locus of the second ball rolling on the second outer central portion is formed in a linear shape and inclined such that a distance from the central axis of the outer joint member increases toward the bottom side of the outer joint member,
a center locus of the second ball rolling on the second outer bottom side portion is formed in an arc shape and disposed in the outer joint member at a position radially inwardly from a tangent at a connecting position between the second outer central portion and the second outer bottom side portion, the tangent extends in a side of the second outer bottom side portion,
the second outer ball groove further includes a second outer opening side portion provided in a range from the second outer central portion to an end of an opening of the outer joint member, and
a center locus of the second ball rolling on the second outer opening side portion is formed in a linear shape and is disposed on an extension line of the center locus of the second ball rolling on the second outer central portion.
2. The constant velocity joint according to claim 1 , wherein the center locus of the first ball rolling on the first outer central portion is formed in a linear shape.
3. The constant velocity joint according to claim 2 , wherein the center locus of the first ball rolling on the first outer central portion is formed in a shape obtained by reversing, with respect to a plane, the center locus of the second ball rolling on the second outer central portion, the plane extending through the joint center and being perpendicular to the central axis of the outer joint member.
4. The constant velocity joint according to claim 3 , wherein
the first outer ball groove includes a first outer bottom side portion provided closer to the bottom side of the outer joint member than the first outer central portion is, and a first outer connection opening side portion provided in a part of the first outer ball groove closer to an opening side of the outer joint member than the first outer central portion is,
a center locus of the first ball rolling on the first outer bottom side portion is provided in an arc shape and disposed in the outer joint member at a position radially inwardly from a tangent at a connecting position between the first outer central portion and the first outer bottom side portion, the tangent extends in a side of the first outer bottom side portion, and
a joint angle at a connecting position between the first outer central portion and the first outer connection opening side portion and a joint angle at a connecting position between the second outer central portion and the second outer bottom side portion are the same angle.
5. The constant velocity joint according to claim 4 , wherein a center locus of the first ball rolling on the first outer connection opening side portion is formed in an arc shape and is formed in a shape obtained by reversing, with respect to the plane, the center locus of the second ball rolling on the second outer bottom side portion, the plane extending through the joint center, and being perpendicular to the central axis of the outer joint member.
6. The constant velocity joint according to claim 5 , wherein
the first outer ball groove includes a first outer opening side portion provided in a range from the first outer connection opening side portion to an end of an opening of the outer joint member, and
a center locus of the first ball rolling on the first outer opening side portion is formed in a linear shape and disposed in a region including a tangent at a connecting position between the first outer connection portion and the first outer opening side portion and placed in the outer joint member radially inwardly from the tangent.
7. The constant velocity joint according to claim 2 , wherein
a maximum joint angle used at a time when the vehicle travels straight defined as a maximum commonly used angle, and
an angle at which the first outer central portion is formed and an angle at which the second outer central portion is formed correspond to the maximum commonly used angle.
8. The constant velocity joint according to claim 1 , wherein
a maximum joint angle used at a time when the vehicle travels straight is defined as a maximum commonly used angle, and
an angle at which the first outer central portion is formed and an angle at which the second outer central portion is formed correspond to the maximum commonly used angle.
9. The constant velocity joint according to claim 1 , wherein
the arc shape of the center locus of the second ball rolling on the second outer bottom side portion has a predetermined arc center point, and
the predetermined arc center point in the second outer bottom side portion is disposed between the central axis of the outer joint member and the second outer ball groove.
10. The constant velocity joint according to claim 9 , wherein
a maximum joint angle used at a time when the vehicle travel straight is defined as a maximum commonly used angle, and
a connecting position between the center locus of the second ball rolling on the second outer bottom side portion and the center locus of the second ball rolling on the second outer central portion is disposed at a position of the maximum commonly used angle.