Abstract: A chain tensioner includes a sleeve fixedly disposed in a cylinder, with a first end of the sleeve inserted in a plunger and a second end of the sleeve protruding out of the plunger. A cylindrical space is defined between an outer periphery of the sleeve and an inner periphery of the cylinder. An oil supply passage opens to the cylindrical space. A communication passage is defined in the sleeve and provides communication between the cylindrical space and a reservoir chamber.

Abstract: 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 which is larger than a 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 ?m. Each internal thread further includes, at a position at which the protruding-side flank intersects with the thread top face, a chamfer configured to receive a bulge resulting from excess materials pushed out from the protruding-side flank during formation of the internal thread by rolling.

Abstract: 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 ?m. 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.

Abstract: A chain tensioner includes a sleeve fixedly disposed in the cylinder, with one end thereof inserted in the plunger and the other end protruding out of the plunger. A cylindrical space is formed between the outer periphery of the sleeve and the inner periphery of the cylinder. An oil supply passage opens to the cylindrical space. A communication passage is defined in the sleeve and provides communication between the cylindrical space and the reservoir chamber.

Abstract: A chain tensioner is provided which is configured such that the air remaining in a pressure chamber can be discharged to the outside through a helical gap defined between a screw and a threaded hole, and through between circumferentially separate radial ends of a spring washer mounted between the screw and a housing. The chain tensioner includes an air discharge groove or grooves formed in the seat surface of the head of the screw such that an annular space defined between the neck of the screw and the inner diameter surface of the spring washer communicates with the outside through the air discharge groove or grooves. Even if foreign objects clog the space between the separate radial ends so as to hinder air from being discharged through between the separate radial ends, the air remaining in the pressure chamber can be discharged to the outside through the air discharge groove or grooves.

Abstract: A chain tensioner is provided which is configured such that the air remaining in a pressure chamber can be discharged to the outside through a helical gap defined between a screw and a threaded hole, and through between circumferentially separate radial ends of a spring washer mounted between the screw and a housing. The chain tensioner includes an air discharge groove or grooves formed in the seat surface of the head of the screw such that an annular space defined between the neck of the screw and the inner diameter surface of the spring washer communicates with the outside through the air discharge groove or grooves. Even if foreign objects clog the space between the separate radial ends so as to hinder air from being discharged through between the separate radial ends, the air remaining in the pressure chamber can be discharged to the outside through the air discharge groove or grooves.

Abstract: A chain tensioner includes a plunger axially slidable in a cylinder to define a pressure chamber, filled with hydraulic oil, whose volume is variable upon axial plunger movement. A restricted passage defined between the plunger and the cylinder communicates the chamber with outside. A spring biases the plunger to increase the pressure chamber volume. An oil supply passage supplies oil to the pressure chamber and a check valve allows only oil flow into the pressure chamber, and includes an annular valve seat, a check ball movable into and out of contact with the valve seat, and a check ball retainer formed by drawing. The retainer includes a tubular portion with a bottom at one end. The tubular portion has an opening, formed by punching outwardly, through which oil can flow in and out. The opening extends to a border between the tubular portion and the bottom of the retainer.

Abstract: 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.

Abstract: A chain tensioner includes a cylindrical cylinder having a closed end, a plunger slidably mounted in the cylinder, and a return spring biasing the plunger. The cylinder is formed with an oil supply passage through which hydraulic oil is introduced into a pressure chamber defined by the plunger and the cylinder. The oil supply passage has an orifice at its end portion facing the pressure chamber. A leak gap is defined between sliding surfaces of the plunger and the cylinder. A damper force is produced by viscous resistance of hydraulic oil flowing from the pressure chamber through the leak gap, and by viscous resistance of hydraulic oil flowing from the pressure chamber into the oil supply passage through the orifice.

Abstract: A chain tensioner includes a housing and a plunger slidably mounted in the housing. A ring receiving groove is formed in the inner periphery of the housing in which a register ring is received. The register ring is engageable in any of a plurality of circumferential grooves formed in the outer periphery of the plunger at equal axial intervals. When the plunger is pushed into the housing, the register ring is trapped between a stopper surface of the ring receiving groove and an engaging surface of one of the circumferential grooves, thereby preventing further retraction of the plunger. The register ring includes a ring portion received in the ring receiving groove and having circumferentially spaced ends, and a pair of operating pieces formed by bending the opposed ends of the ring portion to extending in the same axial direction.

Abstract: 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.

Abstract: 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.

Abstract: A chain tensioner includes a plunger axially slidably inserted in the cylinder for pressing a chain. The plunger defines in the cylinder a pressure chamber filled with hydraulic oil. The volume of the pressure chamber is variable with the axial movement of the plunger. The pressure chamber communicates with the outside of the cylinder through a restricted passage defined between sliding surfaces of the plunger and the cylinder. A spring biases the plunger in a direction to increase the volume of the pressure chamber. The cylinder is formed with an oil supply passage through which the pressure chamber communicates with the outside of the cylinder. The chain tensioner further includes a check valve which allows only a flow of hydraulic oil through the oil supply passage from the outside of the cylinder to the pressure chamber. The check valve includes an annular valve seat, a check ball which is movable into and out of contact with the valve seat, and a retainer formed by drawing and retaining the check ball.

Abstract: A chain tensioner includes a housing defining a cylinder chamber. A plunger is mounted in the cylinder chamber so as to be slidable along an inner surface of the cylinder chamber. A return spring is mounted in the cylinder chamber to bias the plunger outwardly. The housing is formed with an oil supply passage communicating with a pressure chamber defined in the housing behind the plunger. A check valve is disposed at an oil exit of the oil supply passage and configured to close the oil supply passage when the pressure in the pressure chamber is higher than the pressure in the oil supply passage. The housing is formed with a threaded hole extending from an upper portion of an outer periphery of the housing to the pressure chamber. A screw has its external thread in threaded engagement with the internal thread of the threaded hole, whereby a gap, as an air bleed passage, is defined between the internal and external threads.

Abstract: 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.

Abstract: 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.

Abstract: 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.