Patent ID: 11927244
Assignee: DAIDO KOGYO CO., LTD.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A chain transmission device including:
a chain; and
a plurality of sprockets,
wherein:
the chain is wound around the plurality of sprockets under a lubrication environment;
the chain includes outer links, inner links and pins;
each of the outer links includes outer link plates fitted to the pins without rotating relative to the pins and the inner links;
each of the inner links includes inner link plates fitted to the pins and being rotatable relative to the pins;
the outer links and the inner links are alternately coupled in an endless manner;
back surfaces of the outer link plates and back surfaces of the inner link plates are configured to be guided by being in sliding contact with a chain guide;
in the lubrication environment, a friction modifier containing a molybdenum compound is included with a lubrication oil;
an area of each of the outer link plates configured to be in sliding contact with the chain guide is 50% or less of an overall area of one of the outer link plates on a rear surface side; and
an area of each of the inner link plates configured to be in sliding contact with the chain guide is 50% or less of an overall area of one of the inner link plates on a rear surface side;
at least a slidable contact portion of each of the outer link plates and the inner link plates configured to be in sliding contact with the chain guide has a coating film containing 10% or more of a chromium component;
the molybdenum compound is configured to: (i) be decomposed by sliding heat generation when the area of each of the outer link plates or the area of each of the inner link plates comes into sliding contact with the chain guide; and (ii) generate sulfated molybdenum radicals in a boundary lubrication region; and
the chromium component of the coating film is configured to bind with oxygen of the sulfated molybdenum radicals and promote generation of molybdenum disulfide between the area of each of the outer link plates or the area of each of the inner link plates and the chain guide in the boundary lubrication region.