Conveyor belt specification determining method

1. A conveyor belt specification determination method, comprising:

categorizing, into a plurality of categories, a severity of use conditions of a conveyor belt, using a horizontal energy and a vertical energy as indices, the horizontal energy and vertical energy being received by the conveyor belt as a result of objects to be conveyed being fed onto and loaded on an upper cover rubber of the conveyor belt and conveyed;

creating a database in which a permissible range of each of prescribed characteristics is set for each of the categories, the prescribed characteristics including at least wear resistance and cut resistance of the upper cover rubber;

setting a representative rubber physical property of the upper cover rubber that affects each of the prescribed characteristics;

ascertaining a degree of influence of the representative rubber physical property that is set on the prescribed characteristics;

when determining a specification of the conveyor belt, identifying the category of severity from the use conditions of the conveyor belt on a basis of the database;

identifying an appropriate range of the representative rubber physical property for which the prescribed characteristics are in the permissible range in the category that is identified; and

selecting a rubber type, for which the representative rubber physical property is in the appropriate range that is identified, as the upper cover rubber.

2. The conveyor belt specification determination method according to claim 1 , wherein the severity of the use conditions of the conveyor belt is categorized into at least five categories.

3. The conveyor belt specification determination method according to claim 1 , wherein a loss factor and a rubber hardness are included in the representative rubber physical property.

4. The conveyor belt specification determination method according to claim 1 , wherein:

an ambient temperature of a location where the conveyor belt is used is included in the use conditions and a plurality of ambient temperatures differing from each other is set; and

the database is created for each of the ambient temperatures.

5. The conveyor belt specification determination method according to claim 4 , wherein at least three ambient temperatures including a predetermined temperature of −20° C. or lower, a predetermined temperature of 80° C. or higher, and a predetermined temperature from 0° C. to 40° C. are used as the ambient temperatures.

6. The conveyor belt specification determination method according to claim 1 , comprising:

using a sample for each type of rubber, performing rubber wear resistance testing in which apparent compressive stress caused by pressure applied to the sample is varied;

acquiring a relationship between the apparent compressive stress and a surface roughness of the sample obtained from the testing;

acquiring a relationship between the surface roughness and a wear amount per unit friction energy of the sample obtained from the testing;

creating a database on a basis of the acquired relationships, the database showing a correlation between the surface roughness, the apparent compressive stress, and the wear amount per unit friction energy; and

when determining a specification of the conveyor belt, selecting a rubber type, for which the wear amount per unit friction energy of the sample is in a preset permissible range, as the upper cover rubber, on a basis of the apparent compressive stress caused by the pressure applied to the upper cover rubber by conveyed articles and the database showing the correlation.

7. The conveyor belt specification determination method according to claim 1 , comprising:

using samples of a plurality of rubber types having different viscoelastic characteristics, performing rubber wear resistance testing corresponding to the use conditions of each of the categories;

acquiring a relationship between an average wear pitch calculated from a surface roughness of each of the samples obtained from the testing and the viscoelastic characteristics of the sample;

acquiring a relationship between the average wear pitch and an actual wear amount of the sample obtained from the testing;

creating a database on a basis of the acquired relationships, the database showing a correlation between the average wear pitch, the viscoelastic characteristics, and the actual wear amount of the sample; and

when determining a specification of the conveyor belt, selecting a rubber type, for which the actual wear amount of the sample is in a preset permissible range, as the upper cover rubber, on a basis of the viscoelastic characteristics of the rubber type and the database showing the correlation.

8. The conveyor belt specification determination method according to claim 2 , wherein a loss factor and a rubber hardness are included in the representative rubber physical property.

9. The conveyor belt specification determination method according to claim 8 , wherein:

an ambient temperature of a location where the conveyor belt is used is included in the use conditions and a plurality of ambient temperatures differing from each other is set; and

the database is created for each of the ambient temperatures.

10. The conveyor belt specification determination method according to claim 4 , wherein at least three ambient temperatures including a predetermined temperature of −20° C. or lower, a predetermined temperature of 80° C. or higher, and a predetermined temperature from 0° C. to 40° C. are used as the ambient temperatures.

11. The conveyor belt specification determination method according to claim 10 , comprising:

using a sample for each type of rubber, performing rubber wear resistance testing in which apparent compressive stress caused by pressure applied to the sample is varied;

acquiring a relationship between the apparent compressive stress and a surface roughness of the sample obtained from the testing;

acquiring a relationship between the surface roughness and a wear amount per unit friction energy of the sample obtained from the testing;

creating a database on a basis of the acquired relationships, the database showing a correlation between the surface roughness, the apparent compressive stress, and the wear amount per unit friction energy; and

when determining a specification of the conveyor belt, selecting a rubber type, for which the wear amount per unit friction energy of the sample is in a preset permissible range, as the upper cover rubber, on a basis of the apparent compressive stress caused by the pressure applied to the upper cover rubber by conveyed articles and the database showing the correlation.

12. The conveyor belt specification determination method according to claim 10 , comprising:

using samples of a plurality of rubber types having different viscoelastic characteristics, performing rubber wear resistance testing corresponding to the use conditions of each of the categories;

acquiring a relationship between an average wear pitch calculated from a surface roughness of each of the samples obtained from the testing and the viscoelastic characteristics of the sample;

acquiring a relationship between the average wear pitch and an actual wear amount of the sample obtained from the testing;

creating a database on a basis of the acquired relationships, the database showing a correlation between the average wear pitch, the viscoelastic characteristics, and the actual wear amount of the sample; and

when determining a specification of the conveyor belt, selecting a rubber type, for which the actual wear amount of the sample is in a preset permissible range, as the upper cover rubber, on a basis of the viscoelastic characteristics of the rubber type and the database showing the correlation.