Abstract: A torque limiter includes a shaft member, and a cylindrical member which is fitted rotatably on the shaft member. When the cylindrical member is rotated relative to the shaft member in such a state that the cap member is not screwed in the threaded hole and in such a state that the oil release passage is not opened to the outside, the other end portion of the oil release passage circumferentially moves within the circumferentially extended groove while being spaced apart from the circumferentially extended groove.

Abstract: A shear valve protection member is disposed radially outwards of the shear valves and in the same axial position as the shear valves, which can be switched between a tightly attached state in which the strip-shaped shear valve protection member cannot move relatively to a cutting portion which connects to the other member by virtue of a frictional force generated between the cutting portion and itself by tightly attaching the cutting portion thereto in the radial direction and a tight attachment cancelled state in which the strip-shaped shear valve protection member can move in a circumferential direction relative to the cutting portion. The shear valve protection member can be switched between a position where the shear valves are covered with the shear valve protection member and a position where the shear valves are exposed from the shear valve protection member through the through holes therein.

Abstract: A torque limiter includes a cylindrical member, and a shaft member which is fitted rotatably in the cylindrical member. The cylindrical member has a main body portion having in an interior thereof an oil pressure expansion chamber for pressing an inner circumferential surface of the cylindrical member against an outer circumferential surface of the shaft member and an oil release passage which is opened to the oil pressure expansion chamber at one end portion while being closed tightly at the other end portion and which is positioned further radially outwards than an outer circumferential surface of the main body portion. When the cylindrical member stays still relative to the shaft member, the other end portion of the oil release passage is accommodated within a cap member which is screwed to be fixed in a threaded hole.

Abstract: An annular shear valve protection member is disposed on an outer circumferential surface of a circumferentially extending portion of a cutting portion of a shaft member which is positioned radially outwards of shear valves and in the same axial position as the shear valves. Maintenance work such as replacement of shear valves of a torque limiter is performed by switching as required the state of the shear valve protection member 7 between a tightly attached state in which the shear valve protection member is not allowed to move relatively to the outer circumferential surface of the circumferentially extending portion and a tight attachment cancelled state in which the shear valve protection member is allowed to move circumferentially relative to the outer circumferential surface of the circumferentially extending portion by changing the diameter of the shear valve protection member by an operating portion of the shear valve protection member.

Abstract: A torque limiter includes a cylindrical member, and a shaft member which is fitted rotatably in the cylindrical member. The cylindrical member has a main body portion having in an interior thereof an oil pressure expansion chamber for pressing an inner circumferential surface of the cylindrical member against an outer circumferential surface of the shaft member and an oil release passage which is opened to the oil pressure expansion chamber at one end portion while being closed tightly at the other end portion and which is positioned further radially outwards than an outer circumferential surface of the main body portion. When the cylindrical member stays still relative to the shaft member, the other end portion of the oil release passage is accommodated within a cap member which is screwed to be fixed in a threaded hole.

Abstract: There is provided a universal joint which is a universal joint of a block type in which a bearing cup for supporting a trunnion of a joint cross is integrally formed with a key portion, and the bearing cup is joined to be fixed to a yoke by a bolt in a state of fitting the key portion to a key way of the yoke, in which by forming WC—Ni—Cr thermally-sprayed coatings at both side surfaces of the key portion, corrosion resistance of the key portion is promoted, even when used over a long period of time in a drive system of a rolling mill or the like, a clearance between the key portion and the key way caused by corrosion of the key portion is prevented from being brought about, and a stable performance can be maintained over a long period of time by promoting service life of the bearing and preventing an excessively large bending load from being operated to the bolt.

Abstract: At least a race (1c) of a blank (B) for forming a bearing raceway member is hardened by heating and is finished to predetermined precisions. Subsequently, the race (1c) is roller burnished for additional hardening. The blank (B) is formed from a steel for bearing manufacture and is subjected to the roller burnishing, thereby achieving a hardness of HRC65 or more at a surface of the race (1c), and a center-line average roughness Ra of 0.1 ?m or less at the surface of the race (1c) and achieving a hardness of HRC60 or more at the depth of at least 0.2 mm from the surface of (1c).

Abstract: In a shaft coupling monitoring apparatus for monitoring a spider joint using outer peripheries of four shafts of a cross shaft as rolling contact surfaces, each of the shafts contains therein a sensor for detecting any damage on the rolling contact surface thereof. Even in a case where the spider joint is incorporated in a driving shaft such as of a rolling mill, the monitoring apparatus may provide high-accuracy and early detection of any damage such as flaking on the rolling contact surface defined on each of the shafts of the cross shaft.

Abstract: In a shaft coupling monitoring apparatus for monitoring a spider joint using outer peripheries of four shafts of a cross shaft as rolling contact surfaces, each of the shafts contains therein a sensor for detecting any damage on the rolling contact surface thereof. Even in a case where the spider joint is incorporated in a driving shaft such as of a rolling mill, the monitoring apparatus may provide high-accuracy and early detection of any damage such as flaking on the rolling contact surface defined on each of the shafts of the cross shaft.

Abstract: There is provided a universal joint in which a crack is difficult to be produced at a bottom portion of a screw of a bolt for fixing a bearing cup or a bearing holder to a yoke even when excessive large load repeatedly acts and which can withstand to be used over a long period of time under a condition in which a large load of a drive system of a load of a rolling mill or the like acts. In a universal joint of a block type or the like in which a bearing cup 3 for supporting a trunnion 11 of a joint cross 1 through needle-like rollers 2 is fixed to a yoke 4 by a bolt 5, by constituting the bolt 5 by a bolt subjected to roll forming after a heat treatment, a fiber flow along a shape of a screw is formed, a residual compressive stress is generated right below a surface of a bottom portion of the screw, and an allowable fatigue limit is considerably increased in comparison with that of a bolt by turning process of a background art.

Abstract: There is provided a universal joint which is a universal joint of a block type in which a bearing cup for supporting a trunnion of a joint cross is integrally formed with a key portion, and the bearing cup is joined to be fixed to a yoke by a bolt in a state of fitting the key portion to a key way of the yoke, in which by forming WC—Ni—Cr thermally-sprayed coatings at both side surfaces of the key portion, corrosion resistance of the key portion is promoted, even when used over a long period of time in a drive system of a rolling mill or the like, a clearance between the key portion and the key way caused by corrosion of the key portion is prevented from being brought about, and a stable performance can be maintained over a long period of time by promoting service life of the bearing and preventing an excessively large bending load from being operated to the bolt.

Abstract: In a cross joint outwardly fitting a bearing cup to each of four pieces of shafts of a cross shaft member via a cylindrical member, race portions formed on a side of the cross shaft member and on a side of the bearing cup and a shoulder portion provided between respectives of neck portions of two of the shafts of the cross shaft member contiguous to each other are subjected to roller burnishing.

Abstract: A cross shaft joint tiltably coupling two shaft members each other includes: a cross shaft which includes four shaft portions and is arranged between the two shaft members; outer ring cups rotatably provided to the four shaft portions, respectively, the outer ring cups being adapted to be coupled to corresponding shaft members; and an attachment portion to which a balance weight for balancing the outer ring cups can be attached is formed on at least one of the outer ring cups.

Abstract: In a cross joint (1) outwardly fitting a bearing cup (outer ring member 4) to each of four pieces of shafts 2b of a cross shaft member (2) via a cylindrical member (rolling member 3), race portions (2c, 4a) formed on a side of the cross shaft member (2) and on a side of the bearing cup (4) and a shoulder portion (2d) provided between respectives of neck portions of two of the shafts (2b) of the cross shaft member (2) contiguous to each other are subjected to roller burnishing.

Abstract: Across shaft has four trunnions externally provided with roller bearings in a plurality of rows. Each of the trunnions is formed with a recess at its distal end face. A bottom region of the recess is formed in a spherical shape. An inner diameter of an opening region of the recess except the bottom region in a spherical shape is set to be gradually larger toward an opening end edge of the recess. A depth of the recess from the opening end edge to the deepest point is set to be 30 to 70% of the total length of the rollers in an axial direction. By providing this recess is a shape of a punch bowl, rigidity of each of the trunnions of the cross shaft can be reduced, while securing sufficient strength of the trunnion.

Abstract: At least a race (1c) of a blank (B) for forming a bearing raceway member is hardened by heating. The race (1c) thus hardened by heating is finished to predetermined precisions. Subsequently, the race (1c) is roller burnished for hardening the race (1c). The blank (B) is formed from a steel for bearing manufacture or a carbon steel for machine structural use. The blank (B) formed from the steel for bearing manufacture is subjected to the roller burnishing, thereby achieving a hardness of HRC65 or more at a surface of the race (1c), and a center-line average roughness Ra of 0.1 ?m or less at the surface of the race (1c). The blank (B) formed from the carbon steel for machine structural use is hardened by the roller burnishing, thereby achieving a hardness of Hv800 or more at depth of at least 0.2 mm from a surface of the race (1c). Where cutting by turning is adopted as the finishing process, the surface of the race (1c) is finished to a center-line average roughness Ra of 0.

Abstract: A cross shaft joint tiltably coupling two shaft members each other includes: a cross shaft which includes four shaft portions and is arranged between the two shaft members; outer ring cups rotatably provided to the four shaft portions, respectively, the outer ring cups being adapted to be coupled to corresponding shaft members; and an attachment portion to which a balance weight for balancing the outer ring cups can be attached is formed on at least one of the outer ring cups.

Abstract: A cross shaft has four trunnions externally provided with roller bearings in a plurality of rows. Each of the trunnions is formed with a recess at its distal end face. A bottom region of the recess is formed in a spherical shape. An inner diameter of an opening region of the recess except the bottom region in a spherical shape is set to be gradually larger toward an opening end edge of the recess. A depth of the recess from the opening end edge to the deepest point is set to be 30 to 70% of the total length of the rollers in an axial direction. By providing this recess is a shape of a punch bowl, rigidity of each of the trunnions of the cross shaft can be reduced, while securing sufficient strength of the trunnion.

Abstract: In a cross joint (1) outwardly fitting a bearing cup (outer ring member 4) to each of four pieces of shafts 2b of a cross shaft member (2) via a cylindrical member (rolling member 3), race portions (2c, 4a) formed on a side of the cross shaft member (2) and on a side of the bearing cup (4) and a shoulder portion (2d) provided between respectives of neck portions of two of the shafts (2b) of the cross shaft member (2) contiguous to each other are subjected to roller burnishing.

Abstract: Driving apparatus for a rolling mill includes upper and lower work rolls for rolling a workpiece having a longitudinal axis lying in a horizontal plane, upper and lower driving shafts for driving the upper and lower work rolls, respectively, an upper universal joint operatively coupling the upper work roll to the upper driving shaft, and a lower universal joint operatively coupling the lower work roll to the lower driving shaft. The upper and lower work rolls have axes lying in planes parallel to the horizontal plane of the workpiece longitudinal axis and are slanted in opposite directions with respect to the longitudinal axis of the workpiece. The upper and lower driving shafts are disposed symmetrically with respect to the horizontal plane of the workpiece longitudinal axis and a vertical plane passing through the workpiece longitudinal axis.