Abstract: A bearing device for a wheel, which has improved axial assembly accuracy of a sealing member by reducing the amount of springback. The bearing device for a wheel comprises an inner sealing member that blocks an inner opening end of an annular space formed by an outer ring and an inner ring. A sealing ring of the inner sealing member has a core metal fitting in the outer ring and an elastic member joined to the core metal. The elastic member has: a pressing part that is pressed inward in the axial direction when the sealing ring is press-fitted into the outer ring; and a non-pressing part that is not pressed inward in the axial direction when the sealing ring is press-fitted into the outer ring, wherein the axial thickness of the pressing part is thinner than the axial thickness of the non-pressing part.

Abstract: A chain tensioner includes an oil supply passage for supplying hydraulic oil into a pressure chamber defined by a cylinder and a plunger, and a check valve provided at the end of the oil supply passage. A leak gap is defined between the sliding surfaces of the cylinder and the plunger. The plunger is biased by a return spring in the direction in which the plunger protrudes out of the cylinder. A plug is press-fitted in a cylindrical inner periphery of a through hole formed in the plunger to extend from a protruding end surface of the plunger to the pressure chamber to define an air vent passage. It is possible to change the hydraulic damper force simply by replacing the plug with another different type of plug to define a different air vent passage.

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 an oil supply passage for supplying hydraulic oil into a pressure chamber defined by a cylinder and a plunger, and a check valve provided at the end of the oil supply passage. A leak gap is defined between the sliding surfaces of the cylinder and the plunger. The plunger is biased by a return spring in the direction in which the plunger protrudes out of the cylinder. A plug is press-fitted in a cylindrical inner periphery of a through hole formed in the plunger to extend from a protruding end surface of the plunger to the pressure chamber to define an air vent passage. It is possible to change the hydraulic damper force simply by replacing the plug with another different kind of plug to define a different air vent passage.

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 hydraulic auto-tensioner includes a cylinder containing hydraulic oil, a rod inserted in the cylinder, and two coupling pieces mounted to the bottom of the cylinder and the top end of the rod, respectively. A support ring is inserted in the mounting hole of each coupling piece, and a bush is inserted in the support ring. One of the radially inner surface of the mounting hole and the radially outer surface of the support ring is a curved surface such that the support ring is alignable. Radially outwardly extending flanges are formed at one end of the support ring and at the other end of the bush such that the flanges axially face the respective end surfaces of the coupling piece with gaps left therebetween. A coupling arrangement is provided between the support ring and the bush which is adapted to engage both the support ring and the bush when the bush is inserted into the support ring, thereby axially inseparably coupling them together.

Abstract: A hydraulic auto-tensioner includes a cylinder containing hydraulic oil, a rod inserted in the cylinder, and two coupling pieces mounted to the bottom of the cylinder and the top end of the rod, respectively. A support ring is inserted in the mounting hole of each coupling piece, and a bush is inserted in the support ring. One of the radially inner surface of the mounting hole and the radially outer surface of the support ring is a curved surface such that the support ring is alignable. Radially outwardly extending flanges are formed at one end of the support ring and at the other end of the bush such that the flanges axially face the respective end surfaces of the coupling piece with gaps left therebetween. A coupling arrangement is provided between the support ring and the bush which is adapted to engage both the support ring and the bush when the bush is inserted into the support ring, thereby axially inseparably coupling them together.

Abstract: A chain tensioner includes a cylinder having a closed end, an internally threaded plunger axially slidable in the cylinder, a return spring biasing the plunger in the protruding direction from the cylinder, and a screw rod having an external thread in threaded engagement with the internal thread of the plunger. The portion of the screw rod protruding from the plunger abuts a rod seat provided in the cylinder. The screw rod has a rolled external thread and an intermediate portion protruding from the plunger and having an outer diameter smaller than the diameter of the root of the external thread. The screw rod has a forged contact surface, to be contacted with the rod seat, on the axial end face of the intermediate portion. The internal thread may be formed by pressing, and a pressed recess, corresponding to the internal thread, may be formed on the plunger's outer circumference.

Abstract: A chain tensioner includes a cylindrical cylinder having an open end and a bottom, a cylindrical plunger axially slidably inserted in the cylinder and having a bottom and an open end located in the cylinder, a screw rod mounted in the cylinder and having an external thread on an outer periphery thereof, wherein the plunger has a protrusion on an inner periphery thereof which is in threaded engagement with the external thread of the screw rod, and wherein the external thread has a pressure flank for receiving pressure when a force is applied that tends to push the plunger into the cylinder, and a clearance flank, the pressure flank having a larger flank angle than the clearance flank, whereby the external thread is serration-shaped, and a return spring mounted between the plunger and the screw rod and biasing the plunger in a direction to protrude from the cylinder, thereby pressing a chain with the plunger, wherein the protrusion extends only a limited arcuate range of the inner periphery of the plunger.

Abstract: A chain tensioner is provided of which the plunger can be easily machined.

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 cylinder having a closed end, a plunger axially slidably inserted in the cylinder and having an internal thread on the inner periphery thereof, a return spring biasing the plunger in the protruding direction from the cylinder, and a screw rod having an external thread that is in threaded engagement with the internal thread of the plunger. The portion of the screw rod protruding from the plunger abuts a rod seat provided in the cylinder. The external thread of the screw rod is formed by rolling. The screw rod has an intermediate portion protruding from the plunger and having an outer diameter smaller than the diameter of the root of the external thread. A contact surface contact surface of the screw rod to be brought into contact with the rod seat is formed on the axial end face of the intermediate portion by forging. The internal thread may be formed by pressing, and a pressed recess may be formed on the outer circumference of the plunger, corresponding to the internal thread.