Abstract: A power transmission apparatus comprising a pulley 1 and a hub 2 is disclosed. The hub 2 includes an inner hub 21 fixed on a rotary shaft 4 and an elastic member 23 coupled over a joint length L to the outer periphery of the inner hub 21. Elastic member 23 includes a hub-side engaging portion having a series of protrusions arranged in a ring and a cylindrical portion connecting the hub-side engaging portion and the inner hub. Pulley 1 has a pulley-side engaging portion having a series of depressions fitted on the hub-side engaging portion. The engagement between hub-side engaging portion 235 and pulley-side engaging portion 14 forms a torque transmission structure of hub 2 and pulley 1. An axial length TL of a torque transmission surface TS formed by hub-side engaging portion 235 and pulley-side engaging portion 14 in contact with each other is larger than joint length L between the cylindrical portion and inner hub 21.

Abstract: A hub 57 for a power transmission device consists of: an inner hub 59 consisting of a rigid body; a cylindrical section 61 consisting of an elastic body that is formed annularly around an outer circumference of the inner hub 59; an outer ring 63 consisting of a rigid body that is fixed on an outer circumference of the cylindrical section 61 and protrudes in an axially rearward direction; and a hub-side engagement section 65 consisting of an elastic body that is formed on an axially rearward circumferential surface of the outer ring 63 and that is engaged with a pulley side engagement section, wherein connection sections 81 consisting of elastic bodies that connect between a front end of the outer ring 63 and said hub-side engagement section 65 are formed at a front side of an outer circumference of the outer ring 63 where the hub-side engagement section 65 is not formed.

Abstract: In the power transmission device having a torque limiting function for shutting off the transmission of an excessively high torque between the pulley 1 and the rotary shaft 5, the hub 2 and the rotary shaft 5 are connected to each other by means of screw engagement between the female screw portion 2d, which is formed on the inner circumferential face of the hub 2, and the male screw portion 5d which is formed on the outer circumferential face of the forward end portion 5a of the rotary shaft 5, and the seal means 4 for sealing between the hub and the rotary shaft is provided adjacent to the front face or the front and rear faces of the screw engaging portion. The torque limiting function may be provided on the rotary shaft side or the hub side.

Abstract: A bearing according to the present invention includes a cylindrical member formed on and around an outer member of a usual bearing. To firmly connect the cylindrical member to the outer member, grooves having an inclination relative to the axial direction of the bearing are formed not to cross one another on the outer surface of the outer member. The cylindrical member is made of a resin material by molding, and the resin molten by heat in the molding process enters into and adheres to the grooves. In this manner, the cylindrical member is firmly connected to the outer member not to move in both of the rotational and axial directions of the bearing. The grooves formed on the outer surface of the outer member may be grouped, and their inclination relative to the axial direction may be alternately reversed group by group.

Abstract: A screw engagement portion between a pulley and a shaft is provided with a thread in a direction to increase the tightening torque when the pulley is driven. A breakable part broken by the axial tension produced when the tightening torque acting on the screw engagement portion is above a predetermined value, is also provided. The stress to break the breakable part is mainly a tensile stress. The tensile stress is substantially uniformly distributed in a cross section and, hence, the stress distribution of the breakable part can be relatively precisely predicted and analyzed. Consequently, the necessity of determining aspects of the breakable part, such as dimension, material, and the like, by trial and error is reduced. The breakable part can be broken without being subject to fatigue fracture.

Abstract: A power transmission system including an integrally molded hub and elastic member, where stress is inhibited from concentrating at the gate marks remaining after integral molding. In a pulley driven by a belt, a plastic pulley side relief section 1a provided at a pocket section of the pulley and a plastic hub side relief section provided on an iron outer ring of the hub engaged at the pocket section whereby power is transmitted from the pulley to the shaft. The hub side relief section and outer ring forming parts of the hub, the iron inner hub to be fastened to the shaft, and the plastic cylindrical part are integrally molded so that the gate mark for plastic injection is formed near to or further to the outer circumference of the outer ring.

Abstract: When a first damper contacts both of a protruding portion of a pulley body and a protruding portion of a center hub, a second damper is disposed as being apart from the protruding portion of the center hub with a gap. Even when the pulley body is rotated in a reverse direction, no reverse torque is thereby transmitted to the center hub as long as the gap exists, or before the second damper contacts the protruding portion of the center hub. As a result, torque fluctuation is sufficiently absorbed. This prevents the following: a reverse torque is transmitted to the center hub; a torque limiter wrongly acts; a fastening part between a shaft and the center hub loosens; or abnormal noise or aversive vibration takes place.

Abstract: A power transmission device (10) comprises a rotatable rotary part (1) to which a rotatable drive force is transmitted from a drive source and a connection part (2, 3) that connects to the rotary part on one hand, and connecting to a rotating shaft (4) of a device to be driven on the other hand. The rotary part comprises a first concave/convex part (101) arranged in the circumferential direction and the connection part comprises a second concave/convex part (201) arranged in the circumferential direction. The rotary part and the connection part are connected to each other by the insertion of the first concave/convex part and the second concave/convex part into each other. The second concave/convex part is formed by a material having elasticity. Further, in the second concave/convex part, holes or cavities (201a, 201b, 201c) are formed.

Abstract: A power transmission device (10) comprises a rotatable rotary part (1, 2) to which a rotational drive force is transmitted from a drive source and a power transmission shut-off member (3) that shuts off transmission of an excessive torque between the rotary part and a rotating shaft (4) of a device to be driven. The power transmission shut-off member is threadedly coupled to the rotating shaft and can rotate with the rotating shaft. The rotary part is installed so as to be sandwiched between the power transmission shut-off member and the rotating shaft. A disc spring (8), installed between the power transmission shut-off member and the rotary part, is further provided. A caulked part (204a) for preventing a part of the power transmission shut-off member from dropping is provided on the front end side of the rotating shaft.

Abstract: The power transmission device (10) comprises: a rotatable rotary part (1) to which a rotary driving force is transmitted from a driving source; and a power transmission shut-off member (3) for preventing an excessive torque from being transmitted between the rotatable rotary part and a rotating shaft (4) of a driven apparatus and threadedly coupled to the rotating shaft. A hub (2) arranged between the rotary part and the power transmission shut-off member to connect them is located between the power transmission shut-off member and the rotating shaft. The power transmission device further comprises a washer (6) located so as to be sandwiched between the hub and the rotating shaft. The washer is separated from the hub, which is not sandwiched between the washer and an end surface (308) of the power transmission shut-off member near the rotating shaft.

Abstract: A power transmission device includes a pulley 1, a hub 2 and a power shut-off member 3 and further includes a cap 4, one face of which is fastened to an end portion of a rotary shaft 5 by screwing and the other face of which is fastened to the power shut-off member by screwing, so as to transmit power from the power shut-off member to the rotary shaft 5. Power is transmitted between the rotary shaft and the cap not only by this screw fastening portion but also by utilizing a seat surface B or both seat surfaces A and B, wherein the seat surface A is formed on a forward end face 5a provided on the rotary shaft and the seat surface B is formed on a screw root portion (an expanded diameter portion) 5d.

Abstract: Vulcanizing-bonding is carried out using at least a phenolic resin-based vulcanized adhesive F and a silicon compound-based vulcanized adhesive C. Based on an idea of making a penetration of water through a portion bonded with metal difficult, decreasing the adhesion with metal is prevented by utilizing the phenolic resin-based vulcanized adhesive F through which less water can penetrate than the silicon compound-based vulcanized adhesive C, and can increases a thickness of a membrane. Thereby, EPDM or AEM vulcanizable with a peroxide can be strongly bonded to metal, by forming a two-layered structure of the phenolic resin-based vulcanized adhesive F and the silicon compound-based vulcanized adhesive C. Further, a range of selecting a rubber material as an elastic member to be utilized by bonding to metal can be broadened.

Abstract: A power transmission apparatus (10) includes a rotary portion (1) to which turning driving force from a driving source is transmitted and which can rotate, a power cutoff member (3) mechanically connected to the rotary portion (1) and one of the ends of a rotary shaft (5) of a driven apparatus and cutting off transmission of excessive torque between them, and a cap (4) connected to the end of the rotary shaft (5) on one hand and fastened by screw meshing to the power cutoff member (3) on the other hand, and transmitting power from the power cutoff member (3) to the rotary shaft (5). The rotary portion (1), the power cutoff member (3), the cap (4) and the rotary shaft (5) all rotate integrally with one another. The cap (4) has a flange portion (4h) protruding in a radial direction with respect to an axis of the rotary shaft (5) and supporting an axial force.

Abstract: A power transmission device includes: a pulley 1 rotatablely attached to a casing 9; a hub 2 connected to the pulley 1 by an engagement of protrusions with recesses; and a power shutoff member 3 interposed between the hub 2 and a rotary shaft 4. The power shutoff member and the rotary shaft 4 are joined to each other by means of screwing. When a water intrusion path formed between a hub side seating face of the hub and a shaft side seating face 44 of the rotary shaft is formed into a labyrinth structure, water is prevented from entering the seating face. An engagement portion 35 on the power shutoff member side is engaged with a hub side engagement portion 21a so that it can be accommodated in the hub side engagement portion 21a, and the power shutoff member can be rotated together when the hub is rotated. An engagement gap formed between a power shutoff member side engagement portion and a hub side engagement portion in the radial direction perpendicular to an axis of the rotary shaft is in a range from 0.

Abstract: A power transmission apparatus includes a pulley 1 having a belt attached thereto to transmit the rotating drive force, a hub 2 which connects the pulley to a rotating shaft of a driven device, a bearing 7 which rotatably supports the pulley, and a sleeve ring 5 which is fitted and secured to the pulley and attaches the bearing to the pulley to prevent it relatively moving. The sleeve ring is provided, on its first end opposite to the driven device, with a bent portion 5b against which the bearing abuts to restrict further movement of the bearing. An annular retainer 6 is provided on the portion of the bearing adjacent to the drive device. The bearing is secured to the sleeve ring through the annular retainer by calking a second end 5a of the sleeve ring opposite to the first end. The sleeve ring is provided with a projection 5f which projects in the axial direction from the rear surface of the pulley and a casing 9 is provided with an annular groove 9c which at least partly receives therein the projection.

Abstract: A power transmission device which interrupts torque transmission when the torque exceeds a predetermined torque. A torque limiter includes projections formed on a center hub and a pulley. The center hub includes bridges that transmit torque by a pulling force. When a preset torque limit is reached, the projections on the center hub make contact with and move along slanted faces so as to move the center hub in an axial direction relative to the pulley. The bridges are thereby subjected to a bending moment in addition to the pulling force when the torque exceeds the preset torque level, so that the bridges break precisely above the preset torque level due to the reduced fatigue limit.

Abstract: A power transmission device comprises: a pulley 1 pivotally arranged in a casing 9; a hub fixed to a rotary shaft 8; and a torque limiter, having a torque limiting function, for transmitting power between the pulley and the hub and shutting off the transmission of power by breaking a power transmission path in the case where an excessively heavy load is given to the power transmission device. The power transmission device further comprises: a cylindrical member 7 engaged with and fixed to the rotary shaft 8 so that the cylindrical member 7 can be contacted with a hub seating surface 4d; and a seating portion 9c for receiving the cylindrical member, formed in the casing, wherein a gap G is formed between a contact face 7e at the rear end of the cylindrical member and a contact face 9d of the seating portion 9c.

Abstract: In the power transmission device having a torque limiting function for shutting off the transmission of an excessively high torque between the pulley 1 and the rotary shaft 5, the hub 2 and the rotary shaft 5 are connected to each other by means of screw engagement between the female screw portion 2d, which is formed on the inner circumferential face of the hub 2, and the male screw portion 5d which is formed on the outer circumferential face of the forward end portion 5a of the rotary shaft 5, and the seal means 4 for sealing between the hub and the rotary shaft is provided adjacent to the front face or the front and rear faces of the screw engaging portion. The torque limiting function may be provided on the rotary shaft side or the hub side.

Abstract: A power transmission device includes a pulley 1 and a hub 2 having an inner hub 21, a rubber damper 22 and an outer hub 23. A hub side engagement portion 24 formed of an elastic material and arranged either one, or both, of inner peripheral surface and outer peripheral surface of the outer hub engages with a pulley side engagement portion 12, arranged at a position corresponding to the outer hub, of the pulley in concavo-convex fitting to thereby constitute a torque transmission structure between the hub and the pulley. The hub side engagement portion and the pulley side engagement portion have a concavo-convex outer shape and mesh with each other.

Abstract: A power transmission device includes a driving-side rotating body and a driven-side rotating body. The driving-side rotating body rotates via a drive source and has a concave fitting portion. The driven-side rotating body is connected to a rotary shaft and has a convex fitting portion. The convex fitting portion engages the concave fitting portion to transmit rotation of the driving-side rotating body to the driven-side rotating body. The driven-side rotating body includes an annular outer hub formed of resin and an annular inner hub formed of metal. The outer hub is in an outer circumferential part of the driven-side rotating body and has the convex fitting portion. The inner hub is in an inner circumferential part of the driven-side rotating body. The inner hub is insert molded into the outer hub. An outer diameter of the inner hub is larger than an inner diameter of the convex fitting portion.