Conveyor belt

1. A conveyor belt, comprising:

a core layer, having 4 to 8 layers, made of fabric, the core layer having a plain weave structure; and

an upper cover rubber and a lower cover rubber located vertically on either side of the core layer;

at least one layer of the core layer having a strength in a belt width direction ranging from 30% to 70% of a strength in a belt longitudinal direction; wherein:

the conveyor belt is configured to convey objects to be conveyed while being supported in a trough shape projecting downward;

the core layer has a strength in the belt width direction ranging from 30% to 70% of a strength in the belt longitudinal direction and is disposed only in a central portion in the belt width direction; and

the central portion is an area from 50% to 80% of the conveyor belt width in the belt width direction.

2. The conveyor belt according to claim 1 , wherein the layers of the core layer comprise an outermost layer and an innermost layer, and at least the outermost layer and the innermost layer have a strength in the belt width direction ranging from 30% to 70% of a strength in the belt longitudinal direction.

3. The conveyor belt according to claim 1 , wherein all of the layers of the core layer have a strength in the belt width direction ranging from 30% to 70% of a strength in the belt longitudinal direction.

4. The conveyor belt according to claim 1 , wherein the layers of the core layer have the plain weave structure, wefts of the fabric of the layers being aligned across the layers.

5. The conveyor belt according to claim 1 , wherein a coating rubber covers a surface of the core layer, and the upper cover rubber and the lower cover rubber are bonded to warp threads and weft threads which configure the core layer via the coating rubber.