V-ribbed belt and method for manufacturing same
A V-ribbed belt that includes a ribbed surface covered with fabric is provided. The fabric is stretchable in two predetermined directions. A method for manufacturing the V-ribbed belt is also provided. The method includes placing a belt matrix about a mandrel, placing a fabric about the external circumference of the belt matrix which wraps around the mandrel, placing the mandrel inside a shell having a plurality of grooves on the internal circumference, expanding the belt matrix and the fabric toward the internal circumference of the shell and thus pressing the fabric onto the internal circumference having the multi-ribbed structure, and curing the belt matrix with the fabric. The fabric is stretchable to accommodate itself to the multi-ribbed structure.
1. A method for manufacturing a V-ribbed belt, comprising steps of:
placing belt materials comprising a backing fabric, an adhesive rubber, a tensile cord, and a belt matrix about a mandrel;
placing a rib-cover fabric about the external circumference of said belt materials which wrap around said mandrel;
placing said mandrel, which is wrapped by said belt materials and said rib-cover fabric, inside a shell having a plurality of grooves for molding a multi-ribbed structure on its internal circumference;
expanding said belt materials and said rib-cover fabric toward the internal circumference of said shell and thus pressing said rib-cover fabric to said internal circumference to form said multi-ribbed structure; and
curing said belt matrix with said rib-cover fabric and with the belt matrix penetrating into the mesh of said rib-cover fabric;
wherein said rib-cover fabric is stretchable to accommodate itself to said multi-ribbed structure.
2. The method for manufacturing a V-ribbed belt according to claim 1 , wherein the tension per unit width in the mandrel axis direction of said rib-cover fabric is less than or equal to a first value when the extension of said rib-cover fabric along the axis of the mandrel has a value equal to the profile length of a rib in the belt lateral direction divided by the rib pitch, minus one.
3. The method for manufacturing a V-ribbed belt according to claim 2 , wherein the tension per unit width in the mandrel circumferential direction of said rib-cover fabric is less than or equal to a second value when the extension of said rib-cover fabric along the periphery of the mandrel has a value equal to the length of a rib tip in the belt longitudinal direction at said shell, minus the length of said rib-cover fabric in the belt longitudinal direction at the beginning of the molding process, divided by the length of said rib-cover fabric in the belt longitudinal direction at the beginning of the molding process.
4. The method for manufacturing a V-ribbed belt according to claim 1 , wherein said belt matrix's penetration through the mesh of said rib-cover fabric during the pressurization applied in the curing is controlled in order to control characteristics of said ribbed surface.
5. The method for manufacturing a V-ribbed belt according to claim 4 , wherein said penetration of said belt matrix is controlled in part by the stretching of said rib-cover fabric.
6. The method for manufacturing a V-ribbed belt according to claim 1 , wherein said rib-cover fabric includes one of a seamless woven fabric or a seamless knitted fabric which has a predetermined stretchability in the belt longitudinal direction and a predetermined stretchability in the belt lateral direction.
7. The method for manufacturing a V-ribbed belt according to claim 1 , wherein said rib-cover fabric comprises a two-yarn construction including a cotton yarn and a polyurethane yarn.
8. The method for manufacturing a V-ribbed belt according to claim 1 , wherein said rib-cover fabric comprises a yarn construction of three or more fibers or yarns, including a cotton fiber or yarn, a polyurethane fiber or yarn, and another fiber or yarn.
9. The method according to claim 6 , wherein said rib-cover fabric is woven in a process that gives stretchability to both the warp and the weft of said woven rib-cover fabric.
10. The method according to claim 9 , wherein one of said warp and weft directions corresponds to the belt lateral direction and the other corresponds to the belt longitudinal direction.
11. The method according to claim 10 , wherein said process comprises one of curl-crimp finish, woolly finish, air-jet finish, interlace finish, and covering finish.
12. The method according to claim 6 , wherein said rib-cover fabric is seamlessly knitted so as to allow said stretchability in the belt lateral direction and said stretchability in the belt longitudinal direction.
13. The method according to claim 1 , wherein said rib-cover fabric comprises elastic yarn and at least one type of non-elastic yarn.
14. The method according to claim 13 , wherein said elastic yarn comprises polyurethane.
15. The method according to claim 14 , wherein said non-elastic yarn comprises cellulose-based fiber or yarn.