Abstract: A tripod type constant velocity universal joint includes an outer joint member having three track grooves each including roller guide surfaces opposing each other in a circumferential direction of each of the track grooves, a tripod member including three leg shafts, and roller units each including a roller and an inner ring to support the roller. An outer peripheral surface of the roller has a partially spherical surface having a curvature center on an axis of each of the leg shafts. The roller guide surfaces are each formed of a partially cylindrical surface having a curvature center on a horizontal line passing an intersection of a pitch circle of the track grooves and a center line of each of the track grooves, and when no torque is applied to the joint, an end portion of the outer peripheral surface of the roller abuts against the roller guide surfaces.

Abstract: A double-offset plunging type constant velocity universal joint includes inner and outer joint members each having six linear track grooves extending along an axial direction. The inner joint member has a coupling hole at a center portion thereof for coupling a shaft. Six torque transmission balls retained by a cage are incorporated between the linear track grooves of the inner and outer joint members. A ratio TCAGE/DBALL of a minimum thickness (TCAGE) of the cage to a diameter of the torque transmission ball (DBALL) is from 0.225 to 0.245, wherein a ratio DBALL/DS of a diameter (DBALL) of the torque transmission ball to a spline large diameter (DS) of the coupling hole of the inner joint member is from 0.79 to 0.85, and wherein a ball contact ratio (?) of the torque transmission ball is from 1.08 to 1.12.

Abstract: A tripod type constant velocity universal joint includes an outer joint member that includes track grooves, a tripod member that includes three leg shafts protruding in a radial direction, a roller that is inserted into the track groove, and an inner ring that is fitted onto the leg shaft, and rotatably supports the roller. A hardened layer is formed on a surface of each leg shaft by carburizing, hardening, and tempering. The tripod member is formed a steel material having a carbon content of 0.23% to 0.44%. An effective hardened layer depth of the hardened layer by using, as a Ts torque, 0.3 times a minimum static torsional torque at which a shaft coupled to the tripod member causes torsional fracture and 600HV as limit hardness is equal to or greater than a maximum shear stress depth Z when the Ts torque is applied.

Abstract: A plunging type constant velocity universal joint includes outer and inner joint members that transmit torque therebetween through intermediation of a ball while allowing angular displacement. The outer joint member is configured to receive an internal component comprising the ball and the inner joint member so that the internal component is slidable in an axial direction. The universal joint also includes a stopper mechanism that has an annular groove, and is configured to restrict axial displacement of the internal component by allowing the ball to interfere with a circlip fitted to the annular groove. The annular groove has a conical surface, which is inclined with respect to an axial direction so that the conical surface and an axial tangent line at a contact point between the ball and the circlip form a wedge angle opened from an opening end portion of the outer joint member toward a far side.

Abstract: A forging method for a shaft member includes preforming at least one of a plurality of enlarged diameter portions to obtain a semi-finished member, and forming a remainder of the enlarged diameter portions in the semi-finished member using a mold. The mold includes a punch, split dies, and a workpiece receiving member. The forming of the remainder of the enlarged diameter portions includes allowing the semi-finished member having the at least one of the enlarged diameter portions to be placed on the workpiece receiving member, cramping the semi-finished member in its radial direction by closing the split dies, and filling the semi-finished member into forming surfaces of the split dies by the pressure applied by the punch under the state in which the semi-finished member is cramped.

Abstract: Provided is a method of manufacturing an outer joint member of a constant velocity universal joint, which is constructed by forming a cup section having track grooves, and a shaft section, and by welding a cup member and a shaft member, the method including: forming the cup member and the shaft member of medium carbon steel; preparing a cup member having a cylindrical portion and a bottom portion integrally formed by forging, and a joining end surface in a machining step; preparing a shaft member having a joining end surface formed in a machining step; bringing the joining end surface of the cup member and the joining end surface of the shaft member into abutment against each other; welding the cup member and the shaft member by radiating a beam; and performing, after the welding, an ultrasonic flaw detection-inspection step.

Abstract: An inspection device inspects a joint-type outer joint member of a constant velocity universal joint that includes a cup section having a bottomed cylindrical shape and track grooves in an inner periphery thereof for torque transmitting elements, and a shaft section extending from a bottom of the cup section. The inspection device inspects the outer joint member, which is obtained through melt-welding on a cup member forming the cup section and a shaft member forming the shaft section. The inspection device includes a surface inspection unit to inspect for a defect which appears on a surface of the outer joint member due to welding, an internal inspection unit to inspect for an internal defect of a welded portion, and a recording unit to record an inspection result of the inspection. The inspection device is configured to efficiently perform in-line total inspection for the melt-welded joint-type outer joint member.

Abstract: A double-offset plunging type constant velocity universal joint includes inner and outer joint members each having six linear track grooves extending along an axial direction. The inner joint member has a coupling hole at a center portion thereof for coupling a shaft. Six torque transmission balls retained by a cage are incorporated between the linear track grooves of the inner and outer joint members. A ratio TCAGE/DBALL of a minimum thickness (TCAGE) of the cage to a diameter of the torque transmission ball (DBALL) is from 0.225 to 0.245, wherein a ratio DBALL/DS of a diameter (DBALL) of the torque transmission ball to a spline large diameter (DS) of the coupling hole of the inner joint member is from 0.79 to 0.85, and wherein a ball contact ratio (?) of the torque transmission ball is from 1.08 to 1.12.

Abstract: A tripod type constant velocity universal joint includes an outer joint member having track grooves, a tripod member including trunnion journals, and spherical rollers each fitted in a rotatable manner about each of the trunnion journals through intermediation of a plurality of needle rollers. A corner portion is formed at a root portion of each of the trunnion journals so as to restrict movement of the plurality of needle rollers in the axial direction toward the root portion of each of the trunnion journals by interference between an end surface corner rounded portion of each of the plurality of needle rollers and the corner portion at the root portion.

Abstract: A method of manufacturing an outer joint member of a constant velocity universal joint includes forming cup and shaft members of medium carbon steel, preparing, as the cup member, a cup member having cylindrical and bottom portions integrally formed by forging, and a joining end surface formed on an outer surface of the bottom portion, and preparing, as the shaft member, a shaft member having a joining end surface to be joined to the bottom portion of the cup member. The method also includes bringing the joining end surfaces of the cup and shaft members into abutment against each other, and welding the cup and shaft members from an outer side of the cup member to an abutment portion between the cup and shaft members in a radial direction of the cup members.

Abstract: A method of manufacturing an outer joint member of a constant velocity universal includes forming cup and shaft members of medium carbon steel, preparing, as the cup member, a cup member having cylindrical and bottom portions integrally formed by forging, and a joining end surface formed on an outer surface of the bottom portion after the forging, preparing, as the shaft member, a shaft member having a joining end surface to be joined to the bottom portion of the cup member, and bringing the joining end surfaces of the cup and shaft members into abutment against each other. The method also includes welding the cup and shaft members from an outer side of the cup member to an abutment portion between the cup and shaft members in a radial direction of the cup member.

Abstract: For butt-welding, which includes bringing joining end surfaces of a cup member and a shaft member into abutment against each other and radiating a high energy intensity beam from a radially outer side, the shaft member has a recess on a radially inner side of the joining end surface to obtain a welded portion having a closed hollow cavity on a radially inner side after butt-welding. The joining end surface (protruding surface) of the cup member protrudes toward a radially inner side with respect to an inner diameter of the joining end surface of the shaft member. With this, a welded portion of an outer joint member of a constant velocity universal joint, which is manufactured by joining the cup member and the shaft member, can be improved in strength and quality.

Abstract: In an outer joint member of a constant velocity universal joint, a cup member and a shaft member are made of medium to high carbon steel and welded together. The cup member has a bottomed cylindrical shape that is opened at one end, and includes a cylindrical portion, a bottom portion, and a short shaft section of a solid shaft shape protruding from the bottom portion and having a joining end surface. The shaft member has a solid shaft shape and a joining end surface. The joining end surfaces of the cup and shaft members are brought into abutment against each other, and a high energy intensity beam is radiated from an outer side in a radial direction to form a welded portion. A structure of a molten metal at the welded portion is in a mixed phase of ferrite and granular cementite.

Abstract: Provided is a method of manufacturing an outer joint member of a constant velocity universal joint, which is constructed by forming a cup section having track grooves, and a shaft section, and by welding a cup member and a shaft member, the method including: forming the cup member and the shaft member of medium carbon steel; preparing a cup member having a cylindrical portion and a bottom portion integrally formed by forging, and a joining end surface in a machining step; preparing a shaft member having a joining end surface formed in a machining step; bringing the joining end surface of the cup member and the joining end surface of the shaft member into abutment against each other; welding the cup member and the shaft member by radiating a beam; and performing, after the welding, an ultrasonic flaw detection-inspection step.

Abstract: In a tripod type constant velocity universal joint 1, when D1 represents a large inner diameter being a diameter of a circle connecting radially outer end portions of roller guide surfaces 7 and D2 represents a small inner diameter being a diameter of a circle connecting radially inner end portions of the roller guide surfaces 7, a ratio D2/D1 between the small inner diameter D2 and the large inner diameter D1 is set within a range of from 0.73 to 0.80. Further, when d represents a large diameter of a spline formed in a trunnion hub 8 of a tripod member 3 and PCD represents a pitch circle diameter of the roller guide surfaces 7, a ratio d/PCD between the large diameter d and the pitch circle diameter PCD is set to 0.60 or more.

Abstract: A cup member has a cylindrical portion, a bottom portion, and a short shaft portion having a solid shaft shape and including a joining end surface at an end portion thereof. A shaft member has a solid shaft shape and includes a joining end surface at one end thereof. The joining end surfaces of the cup and shaft members are brought into abutment against each other and welded from a radially outer side to form a welded portion. At this time, center segregation is prevented from interfering with the welded portion. The cup member is formed by forging including upsetting a billet having a columnar shape successively in a plurality of stages, extruding the cylindrical portion and the short shaft portion, and ironing the cylindrical portion. In the course of the upsetting, a region of the billet corresponding to a bottom side of the cup member is narrowed.

Abstract: Provided is a method of manufacturing an outer joint member of a constant velocity universal joint, which is constructed by forming a cup section having track grooves, and a shaft section, and by welding a cup member and a shaft member, the method including: forming the cup member and the shaft member of medium carbon steel; preparing a cup member having a cylindrical portion and a bottom portion integrally formed by forging, and a joining end surface in a machining step; preparing a shaft member having a joining end surface formed in a machining step; bringing the joining end surface of the cup member and the joining end surface of the shaft member into abutment against each other; welding the cup member and the shaft member by radiating a beam; and performing, after the welding, an ultrasonic flaw detection-inspection step.

Abstract: A plunging type constant velocity universal joint includes outer and inner joint members that transmit torque therebetween through intermediation of a ball while allowing angular displacement. The outer joint member is configured to receive an internal component comprising the ball and the inner joint member so that the internal component is slidable in an axial direction. The universal joint also includes a stopper mechanism that has an annular groove, and is configured to restrict axial displacement of the internal component by allowing the ball to interfere with a circlip fitted to the annular groove. The annular groove has a conical surface, which is inclined with respect to an axial direction so that the conical surface and an axial tangent line at a contact point between the ball and the circlip form a wedge angle opened from an opening end portion of the outer joint member toward a far side.

Abstract: A method of manufacturing an outer joint member of a constant velocity universal joint includes forming cup and shaft members using medium carbon steel, preparing, as the cup member, a cup member having cylindrical and bottom portions integrally formed, and a joining end surface formed on an outer surface of the bottom portion, preparing, as the shaft member, a shaft member having a joining end surface to be joined to the bottom portion of the cup member, and bringing the joining end surfaces of the cup and shaft members into abutment against each other. The method also includes welding the cup and shaft members from an outer side of the cup member to an abutment portion between the cup and shaft members in a radial direction of the cup member under a state in which a hollow cavity portion is formed inside the abutment portion.

Abstract: Provided is a method of manufacturing an outer joint member of a constant velocity universal joint, which is constructed by welding a cup member and a shaft member, the method including: forming the cup member and the shaft member of medium carbon steel; preparing; preparing; bringing the joining end surface of the cup member and the joining end surface of the shaft member into abutment against each other; welding the cup member and the shaft member; and performing, after the welding, ultrasonic flaw detection-inspection from any one of a surface side of the cup member and a surface side of the shaft member, which has the another one of the joining end surface of the cup member and the joining end surface of the shaft member.