Transfer belt

1. A transfer belt wound between a primary pulley and a secondary pulley of a continuously variable transmission, the transfer belt comprising:

a plurality of elements, each of which has a body that includes a saddle surface and a pair of pillars that extend toward a radially outer side of the transfer belt from both sides of the saddle surface in a width direction; and

a bind ring that binds the plurality of elements annularly with an inner peripheral surface of the bind ring contacting the saddle surface of each of the plurality of elements, wherein:

the saddle surface is formed as a convex curved surface curved convexly toward the radially outer side of the transfer belt;

a rocking edge is formed in both pair of pillars of each of the plurality of elements so as to extend in the width direction and serve as a support point during turning motion of an element in contact with an adjacent element;

the rocking edge has a width in a radial direction of the transfer belt;

a top of the convex curved surface of the saddle surface is formed so as to be positioned in a range of the width of the rocking edge in the radial direction;

the rocking edge is formed in an arcuate shape as viewed in a side view;

the top of the convex curved surface of the saddle surface is positioned in a range of the arcuate shape in the radial direction;

the rocking edge is formed at an intermediate position that is at a same radial height as the top of the convex curved surface of the saddle surface, the intermediate position being halfway between a first support position for turning motion of the element which is wound around the secondary pulley at a minimum speed ratio of a speed ratio range used in operation of the continuously variable transmission and a second support position for turning motion of the element which is wound around the secondary pulley at a maximum speed ratio of the speed ratio range;

the bind ring is a single ring-shaped member formed by stacking a plurality of band-like rings in the radial direction;

the convex curved surface is formed such that a center in the width direction of the saddle surface projects most; and

the bind ring curves convexly toward the radially outer side of the transfer belt.

2. The transfer belt according to claim 1 , wherein

the rocking edge is divided to be located at both ends in the width direction by a non-contact portion provided at a center in the width direction.

3. The transfer belt according to claim 1 , wherein

the rocking edge is formed so as to overlap a virtual line that extends in the width direction of the element through the top of the convex curved surface of the saddle surface as viewed in a plan view of the element.

4. The transfer belt according to claim 3 , wherein

the arcuate shape of the rocking edge is formed at a position overlapping the virtual line as viewed in the plan view.

5. A transfer belt wound between a primary pulley and a secondary pulley of a continuously variable transmission, the transfer belt comprising:

a plurality of elements, each of which has a body that includes a saddle surface and a pair of pillars that extend toward a radially outer side of the transfer belt from both sides of the saddle surface in a width direction; and

a bind ring that binds the plurality of elements annularly with an inner peripheral surface of the bind ring contacting the saddle surface of each of the plurality of elements, wherein:

the saddle surface is formed as a convex curved surface curved convexly toward the radially outer side of the transfer belt;

a rocking edge is formed in both pair of pillars of each of the plurality of elements so as to extend in the width direction and serve as a support point during turning motion of an element in contact with an adjacent element;

the rocking edge has a width in a radial direction of the transfer belt;

a top of the convex curved surface of the saddle surface is formed so as to be positioned in a range of the width of the rocking edge in the radial direction;

the rocking edge is formed in an arcuate shape as viewed in a side view;

the top of the convex curved surface of the saddle surface is positioned in a range of the arcuate shape in the radial direction;

the rocking edge is formed at a predetermined position that is at a same radial height as the top of the convex curved surface of the saddle surface, the predetermined position is closer to a first support position for turning motion of the element which is wound around the secondary pulley at a minimum speed ratio of a speed ratio range used in operation of the continuously variable transmission than to an intermediate position that is halfway between the first support position and a second support position for turning motion of the element which is wound around the secondary pulley at a maximum speed ratio of the speed ratio range;

the bind ring is a single ring-shaped member formed by stacking a plurality of band-like rings in the radial direction;

the convex curved surface is formed such that a center in the width direction of the saddle surface projects most; and

the bind ring curves convexly toward the radially outer side of the transfer belt.

6. The transfer belt according to claim 5 , wherein

the rocking edge is divided to be located at both ends in the width direction by a non-contact portion provided at a center in the width direction.

7. The transfer belt according to claim 5 , wherein

the rocking edge is formed so as to overlap a virtual line that extends in the width direction of the element through the top of the convex curved surface of the saddle surface as viewed in a plan view of the element.

8. The transfer belt according to claim 7 , wherein

the arcuate shape of the rocking edge is formed at a position overlapping the virtual line as viewed in the plan view.