| 摘要 |
PURPOSE:To obtain a sleeve for driving a caterpillar with high durability against abrasion of earth and sand and repeated high load for a long time by combining a surface layer of sintered hard material to disperse particles above MHv 1,000 at an area rate above 15% on a contact face of a steel sleeve with a sprocket. CONSTITUTION:This sleeve is composed of a steel sleeve main body 1 and a surface layer 2 of sintered hard material in which hard particles with hardness above MHv 1,000 are dispersed at an area rate above 15% and the difference of coefficient of thermal expansion with the sleeve main body is within 0.3X10<-5>/ deg.C (only in the thermal range of 0-600 deg.C); the surface layer of the said sintered hard material is combined on a partial or the whole surface of the contact part of the sleeve main body with a sprocket for transmitting a drive power. When the hardness of the hard particles is under MHv 1,000 or the dispersion of the hard particles is under 15% area rate, the durability against abrasion of earth, wet sand, and the like is greatly reduced to loose the advantage to prolong the life of the sleeve for driving a caterpillar. When the difference of the thermal expansion coefficient between the sintered hard material and the sleeve main body surpasses 0.3X10<-5>/ deg.C, the cooling process after dispersing combination at high temperature and the cementation after the combination, or the contraction difference after hardening, cause cracking. |
