Chain tensioner

摘要

Provided is a chain tensioner that can, with a simple structure, supply sufficient and necessary oil when restarted after a long time after the stop of oil supply, and control pressing force in accordance with operating conditions during the drive, thereby reducing vibration of the chain not only when restarted but also during the drive. In a chain tensioner 100 in which a plunger 120 inserted in a plunger bore of a tensioner body 110 is biased outward by biasing means 140 provided in an oil pressure chamber 101 to be extendable and contractible, an oil supply hole 114, an oil supply space 102, and a plunger hole 124 that together form a continuous oil supply passage is formed in such a shape that an oil amount changes in accordance with a position of the plunger 120.

主权项

1. A chain tensioner, comprising:
a tensioner body having a cylindrical plunger bore with an open end; a cylindrical plunger slidably inserted into the plunger bore, the plunger including a plunger body and a check valve provided inside the plunger body; and biasing means accommodated inside an oil pressure chamber formed between the plunger bore and a rear end of the plunger such as to be able to expand and contract and to bias the plunger outward, wherein an oil reservoir chamber is formed on an outer side than the check valve inside the plunger body, an oil supply space is formed between an inner circumferential surface of the plunger bore and an outer circumferential surface of the plunger body, an oil supply hole for supplying oil to the oil supply space is formed in the plunger bore, a plunger hole for supplying oil from the oil supply space to the oil reservoir chamber is formed in the plunger body, the oil supply hole, the oil supply space, and the plunger hole together form a continuous oil supply passage, the oil supply passage is formed in such a shape that an oil amount changes in accordance with a position of the plunger, wherein the oil supply space is formed between a plunger groove formed in the outer circumferential surface of the plunger body and the inner circumferential surface of the plunger bore, the plunger groove having chamfered ends defining ends of the oil supply space and having portions with different depths intermediate between the chamfered ends along a protruding direction of the plunger, and wherein widths, in the protruding direction of the plunger, of said portions with different depths are larger than a diameter, in the protruding direction of the plunger, of said oil supply hole such that a first of said portions with different depths is aligned with and extends fully across said oil supply hole, in the protruding direction of the plunger, when said plunger is in a first position and a second of said portions with different depths is aligned with and extends fully across said oil supply hole, in the protruding direction of the plunger, when said plunger is in a second position.