A fixed-side support arm (17) of a torsion coil spring (10) is provided with a locking portion (17a) and a pressing portion (17c). The locking portion (17a) is housed in a recessed spring housing portion (22) provided in a lever (9), and an engaging portion (22a) abuts against the locking portion (17a) to lock a biasing force of the spring. A pressing force (F) is applied to the pressing portion (17c) to remove the locking portion (17a) from the spring housing portion (22), thereby releasing the locking by the engaging portion (22a).

An object of the present invention is to provide a tensioner lever that can reduce vibration and noise when the chain runs, and realize smooth attachment into an engine with minimal deformation of the lever body with a simple configuration. A tensioner lever according to the present invention includes a lever body and a torsion coil spring pressed the lever body toward the chain. The lever body includes a stopper member mounting part where a stopper member by which the support arm of the torsion coil spring is locked and which retains the torsion coil spring in a compressed state is removably mounted. The stopper member mounting part is located closer to a distal end of the lever body than a center position in the longitudinal direction of the lever body, or a center of gravity position of the lever body.

A chain tensioner is formed with internal threads each including a push-in-side flank, a protruding-side flank , and a thread top face. The push-in-side flank has a flank angle larger than the flank angle of the protruding-side flank. The push-in-side flank and the protruding-side flank are rolled surfaces formed by rolling, and have a surface roughness smaller than Ra 1.0 μm. Each internal thread further includes, at its position at which the protruding-side flank intersects with the thread top face, a chamfer configured to receive a bulge moving from the protruding-side flank during rolling.

A tensioner comprising a base having a cylindrical portion extending axially, the cylindrical portion comprising a radially outer surface and a receiving portion that is radially inward of the radially outer surface, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the radially inward receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm.

An object of the present invention is to provide a chain guide, which allows easy assembling of a guide shoe to a base member, and reliably prevents detachment of the guide shoe from the base member resulting from vibration or the like during the running of a chain. Provided is a chain guide wherein a base member includes an attachment extension extending upward from a base body part beyond a support surface, and a base-side engaged part formed in the attachment extension, a guide shoe includes a flexible extension extending from a shoe body part, and a shoe-side engaging part formed in the flexible extension, and the shoe-side engaging part is hooked to the base-side engaged part from below, or diagonally from below, or from front or back, to be positioned on the far side of the base-side engaged part during engagement therebetween.

A tensioner comprising a base having a cylindrical portion extending axially, the cylindrical portion comprising a radially outer surface and a receiving portion that is radially inward of the radially outer surface, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the radially inward receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm.

A tensioner comprising a base having a cylindrical portion extending axially, the cylindrical portion comprising a radially outer surface and a receiving portion that is radially inward of the radially outer surface, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the radially inward receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm.

To provide a simple-structured tensioner that generates less knocking noise at the start-up of the engine and that prevents an excessive chain tension, severe friction, noise or vibration during the running of the engine, while also reducing production costs. The tensioner includes a ring control mechanism that controls the position of a resilient ring. The ring control mechanism includes a front-side restricting part having a front-side restricting surface and capable of restricting forward movement of the resilient ring, and a rear-side restriction member having a rear-side restricting surface and capable of restricting rearward movement of the resilient ring. The front-side restricting part is fixed to or formed integrally with the housing. The rear-side restriction member is disposed movable in a front to back direction relative to the housing and the plunger.

An object of the present invention is to provide a tensioner lever capable of consistently exerting appropriate reaction force to various tension fluctuations in conjunction with varying chain behavior, and reducing vibration and noise when the chain runs. The tensioner lever of the present invention includes a torsion coil spring having a pressing arm in which a distal end portion abuts on a lever body to form a first load point, and a support arm in which a distal end portion abuts on a support part provided to an attachment surface to form a first support point. The tensioner lever further includes a spring load adaption structure configured to form one or both of a second loading point and a second support point when a certain level or more of load is received from the chain.

A cam shaft drive device includes a chain, a guide lever, a chain chamber, which is provided in a cylinder head, a support bolt, which pivotably supports the guide lever, the support bolt including a head portion, a male screw portion, and a shaft portion, which is inserted through the support hole of the guide lever, an insertion hole, which is through which the support bolt is inserted, and a female screw hole, which is provided in the rear wall and into which the male screw portion is screwed, wherein a length from a rear end to a front end of the shaft portion is longer than an axial distance from a front end of the support hole to a front end of the insertion hole in a state where the guide lever abuts on the rear wall.