Ntn Corporation

Yoshiaki Ryouno

Seiji Sato

Satoshi Kitano

Kouichi Onimaru

Hisashi Hayakawa

Katsuaki Sasaki

Tasuku Furukawa

Shuguang Lian

A rolling contact bearing assembly includes a seal member having a seal lip segment. The seal lip segment includes a waist portion having, as viewed in a cross section, a bent V-shape such that a surface of the seal lip segment on outer side defines a relief recess and also includes a protrusion portion distal to the waist portion and having a tapered shape narrowing towards a free end thereof. The seal member installed in the bearing assembly applies urging force on one of inner and outer raceway rings, against change in degree of interference of the protrusion portion with the raceway ring. The protrusion portion includes such high wear material that rotation of the bearing assembly results in wear of the protrusion portion to cause the protrusion portion to make non-contact status or light contact status of a contact pressure of substantially zero.

Rolling bearing

A chain tensioner includes a housing having a closed bottom. A rod is axially movably inserted in the housing for pressing a chain. A wear ring is mounted to the outer periphery of the rod and is biased by a return spring mounted in the housing in a direction away from the bottom of the housing. A nut member is mounted between the wear ring and the bottom of the housing so as to be coaxial with the housing and axially movable relative to the housing. A ring-shaped spring member is provided between the nut member and the bottom of the housing to support the nut member. A screw rod is provided between the rod and the bottom of the housing and in threaded engagement with the nut member. A spring is provided between the screw rod and the bottom of the housing to bias the screw rod in a direction away from the bottom of the housing. The screw rod has an end surface that is in abutment with the rod.

Chain tensioner

A chain tensioner includes a housing defining a cylinder chamber having a closed end. A cylindrical plunger having a closed front end is slidably received in the cylinder chamber. A nut member and a return spring are mounted in the cylinder chamber. The return spring biases the plunger outwardly of the housing to press its closed end against a pivotally supported chain guide. The nut member has a serration-shaped internal thread formed on the inner periphery thereof which is in threaded engagement with a serration-shaped external thread formed on the outer periphery of the screw rod. The screw rod is biased toward the closed end of the plunger by a rod spring. A damper is mounted between the front end of the screw rod and the closed front end of the plunger for damping, in cooperation with the return spring, a pushing force applied to the plunger, and for allowing the screw rod and the plunger to move relative to each other in a direction in which the distance between respective remote ends thereof decreases by an amount not less than an axial play present between the internal and external threads.

An auto-tensioner includes a housing having an open end and a closed bottom at another end. A cylindrical plunger is slidably inserted in the housing with its open end facing the closed bottom of the housing and its other end protruding from the housing. A ring-shaped seal member is mounted between the inner periphery of the housing and the outer periphery of the plunger for hermetically sealing oil in the housing. A screw rod and a nut member are mounted in the plunger so as to be coaxial with the plunger, with the nut member in threaded engagement with the screw rod. A return spring is mounted between the nut member and the plunger to bias the nut member and the plunger in a direction axially away from each other. A spring is mounted between the screw rod and the closed bottom of the housing to bias the screw rod in a direction away from the closed bottom of the housing.

Auto-tensioner

A stepped set groove having shallow and deep portions is formed in the inner periphery of a cylinder chamber formed in a housing of a chain tensioner near its open end. A radially and elastically deformable set ring having circumferentially separated ends is received in the set groove in a radially compressed state. The set ring has at the respective ends thereof a pair of grip portions which are received in a cutout formed in housing at its front end. By engaging the set ring in an engaging groove formed in the outer periphery of the plunger near its front end and the shallow portion, it is possible to keep the plunger pushed into the cylinder chamber. In this state, the chain tensioner is mounted in position. One of the grip portions is brought into abutment with one of the circumferentially opposed end walls of the cutout to prevent the plunger from rotating about its axis in such a direction that the axial gap between an internal thread of the plunger and an external thread of a screw rod inserted in the plunger disappears. Thus, it is possible to keep the axial gap larger than the axial distance by which the plunger has to be moved to move the set ring from the shallow portion into the deep portion. This makes it possible to disengage the set ring from the engaging groove by pushing the plunger into the cylinder chamber.

Growing community of inventors

Iwata, Japan

Yoshiaki Ryouno