Abstract: A power transmission device includes an armature that is shaped into a circular ring form. The armature is configured to be coupled with a rotor by an electromagnetic attractive force of an electromagnet at a time of energizing the electromagnet and is configured to be decoupled from the rotor at a time of deenergizing the electromagnet. The armature has an armature-side friction surface that is configured to contact a rotor-side friction surface of the rotor at the time of energizing the electromagnet. The armature-side friction surface has a plurality of grooves, each of which extends from a radially inner end portion of the armature-side friction surface to a location that is on a radially inner side of a radially outer end portion of the armature-side friction surface.

Abstract: A power transmission device includes an armature that is shaped into a circular ring form. The armature is configured to be coupled with a rotor by an electromagnetic attractive force of an electromagnet at a time of energizing the electromagnet and is configured to be decoupled from the rotor at a time of deenergizing the electromagnet. The armature has an armature-side friction surface that is configured to contact a rotor-side friction surface of the rotor at the time of energizing the electromagnet. The armature-side friction surface has a plurality of grooves, each of which extends from a radially inner end portion of the armature-side friction surface to a location that is on a radially inner side of a radially outer end portion of the armature-side friction surface.

Abstract: A power transmission device includes an armature that is shaped into a circular ring form and is configured to be coupled with a rotor by an electromagnetic attractive force of an electromagnet at a time of energizing the electromagnet and is configured to be decoupled from the rotor at a time of deenergizing the electromagnet. The armature has an armature-side friction surface that is configured to contact a rotor-side friction surface of the rotor at the time of energizing the electromagnet. Grooves are formed at the armature-side friction surface such that each of the grooves extends in a form of slit from a radially inner side toward a radially outer side of the armature-side friction surface. A different type of material, which is different from a material of the armature-side friction surface, is placed in the grooves.

Abstract: A power transmission device that transmits a rotational driving force outputted from a driving source to a target device to be driven includes: a driving rotor rotated by the rotational driving force; a driven rotor that rotates with a rotary shaft of the target device; and a connection member. The connection member has a plate shape extending perpendicular to the rotary shaft. The connection member is connected at least one of the driving rotor and the driven rotor, and is capable of connecting the driving rotor and the driven rotor to each other. The connection member has a through hole, and the driven rotor has an overlapping portion disposed overlapping with the through hole when viewed in the axial direction of the rotary shaft.

Abstract: A power transmission device that transmits a rotational driving force outputted from a driving source to a target device to be driven includes: a driving rotor rotated by the rotational driving force; a driven rotor that rotates with a rotary shaft of the target device; and a connection member. The connection member has a plate shape extending perpendicular to the rotary shaft. The connection member is connected at least one of the driving rotor and the driven rotor, and is capable of connecting the driving rotor and the driven rotor to each other. The connection member has a through hole, and the driven rotor has an overlapping portion disposed overlapping with the through hole when viewed in the axial direction of the rotary shaft.

Abstract: A pulley includes a radial rolling bearing and a pulley main body which are integrated to each other by an insert molding method. Therefore, a metal insert member is not required between the resin pulley main body and the radial rolling bearing, thereby reducing production cost of the pulley. Further, an axial dimension of an outer ring of the radial rolling bearing is set larger than an axial dimension of an inner ring thereof, so that a contact area between the radial rolling bearing and the pulley main body is increased. Therefore, a connection strength between the radial rolling bearing and the pulley main body is increased, and a surface area of the radial rolling bearing is increased, thereby improving heat radiation performance of the radial rolling bearing.

Abstract: In an electromagnetic clutch, a rotor, an armature and a stator housing including an electromagnetic coil are assembled to a center hub through a bearing member. Therefore, by assembling the center hub to an engine crank shaft, an assembling operation of the electromagnetic clutch to a vehicle is finished. In addition, a stator plate fixed to the stator housing is fixed to an engine through a bushing made of an elastic material. Therefore, a vibration displacement of the stator housing relative to the rotor, generated due to vibration of the engine, can be absorbed.

Abstract: A pulley includes a radial rolling bearing and a pulley main body which are integrated to each other by an insert molding method. Therefore, a metal insert member is not required between the resin pulley main body and the radial rolling bearing, thereby reducing production cost of the pulley. Further, an axial dimension of an outer ring of the radial rolling bearing is set larger than an axial dimension of an inner ring thereof, so that a contact area between the radial rolling bearing and the pulley main body is increased. Therefore, a connection strength between the radial rolling bearing and the pulley main body is increased, and a surface area of the radial rolling bearing is increased, thereby improving heat radiation performance of the radial rolling bearing.

Abstract: In an electromagnetic clutch, a rotor, an armature and a stator housing including an electromagnetic coil are assembled to a center hub through a bearing member. Therefore, by assembling the center hub to an engine crank shaft, an assembling operation of the electromagnetic clutch to a vehicle is finished. In addition, a stator plate fixed to the stator housing is fixed to an engine through a bushing made of an elastic material. Therefore, a vibration displacement of the stator housing relative to the rotor, generated due to vibration of the engine, can be absorbed.

Abstract: A device for transmitting rotational power from a rotational power source to a driven device having a drive shaft includes at least one elastic connecting member defining outer and inner peripheral surfaces. First and second holder members radially cooperate with each other to circumferentially hold the at least one elastic connecting member during normal operation to transmit the rotation, and are disconnected by the deformation of the at least one elastic connecting member when the torque on the drive shaft exceeds a predetermined cutoff torque level. A weakened portion is provided at least one of the first and second holder members. The weakened portion aids the deformation of at least one of the first and second holder members to reduce a torsional spring coefficient which is defined by the ratio of the relative rotational angle between the first and second holder member to the torque on the drive shaft.

Abstract: A stator housing of an electromagnetic clutch has a receiving portion for receiving an exciting coil and a bottom with through holes. The through holes are formed by pressing so as to have a tapered portion, a cross-sectional area of which becomes large toward the opposite side of the exciting coil. The exciting coil is received in the receiving portion so as to face the through holes and fixed by a molded resin which is filled into a space between the exciting coil and the receiving portion as well as the through holes. Accordingly, a fixing structure for preventing the exciting coil and the mold resin from coming out of the stator housing can be provided with low cost and high productivity.

Abstract: A device for transmitting rotational power from an automobile engine to a compressor for use in an automobile air conditioning system is provided. The device includes a pulley, which is supported on a housing of the compressor for rotation, for receiving rotational power from the automobile engine, and a hub connected to the drive shaft. At least one elastic member which defines outer and inner peripheral surfaces is provided. A first holder member is provided along the outer periphery of the hub for holding the elastic member. A second holder member, which is connected to the pulley, is provided for holding the elastic member. The first and second holder members radially cooperate with each other to circumferentially hold the elastic member during normal operation to transmit the rotation. The first and second holder members are disconnected by deformation of the at least one elastic member when a relative rotation between the pulley and drive shaft occurs.

Abstract: A magnetic clutch includes a rotor and an armature facing to each other for establishing a coupling connection. A serpentine magnetic circuit is formed in the rotor and the armature. A method for manufacturing a rotor of a magnetic clutch of the invention comprises the step of deforming a single ring-shaped plate of a magnetic material, by a plastic deformation process such as cold forging, into a ring-shaped element comprising generally concentric inner and outer cylindrical walls, and a ring-shaped bottom wall. Prior to or after or simultaneously with this step, ring grooves are formed on the bottom wall. A nonmagnetic material is then filled in the ring grooves, and the bottom surface of the bottom wall is cut to form a friction surface. By this cutting, the nonmagnetic material is exposed at the friction surface.

Abstract: A device for transmitting rotational power from a rotational power source to a rotational driven member is provided with a first rotating member provided for rotation in a rotational direction about an axis, and a second rotating member provided for rotation about the same axis. The first rotating member is connected to the rotational power source and the second rotating member is connected to the rotational driven member. An mechanism for rotationally connecting the first and second rotating member is provided. The connecting mechanism is provided with at least one elastic member made of a rubber material; a first holder member for holding the elastic member from the radially outside of the elastic member; and a second holder member for holding the elastic member from the radially inside of the elastic member. The first and second holder members are mounted to one of the first and second rotating members.

Abstract: An electromagnetic clutch which can completely meet an excessive starting torque upon starting. It is assumed that the width of each first gap in the rotating direction is the deformation and displacement of each elastic member which is smaller than the deformation and displacement of the elastic member based on a peak torque T1 just after the electromagnetic clutch is activated, and is generated based on a torque T slightly larger than a maximum torque T2 after the lapse of a predetermined time. Thus, when a torque (for example, T1) larger than the torque T is exerted on the elastic member, the outer peripheral surface of a second fitting portion abuts against the inner peripheral surface of a flange portion. As a result, the elastic member is not deformed by more than the above described deformation and displacement.

Abstract: An electromagnetic clutch capable of reducing a noise generated upon contact of an armature with rotor. Connecting member 20 for connecting inner and outer rings 5a and 5b of the armature are integrally formed with arms 19 extending radially inwardly from locations where the connection members 20 are connected to the inner ring 5a by rivets 12. The arms 17 are in face to face contact with an elastic member 18 made of rubber, which is held by the inner hub 7 by means of a retainer 19. Upon the movement of the armature 5 toward to rotor 4 by means of an electromagnetic force, just before the contact of the armature 5 with the rotor 4, a steep increase in a force for opposing the movement of the armature 5 with respect to the rotor 4 is obtained, thereby reducing an impact upon the contact, and reducing the noise.