Pulley with two flanges, and method of producing pulley with two flanges

A pulley with two flanges comprising:

• a pulley body, and
• a flange body joined to the pulley body in a male-female fitting manner;
• wherein
• the pulley body includes:
• a first flange that protrudes outward in a radial direction perpendicular to a rotation axis, at a first end of the pulley body in an axial direction parallel to the rotation axis;
• and
• a fitting protrusion that has an annular shape and protrudes in the axial direction, at a second end of the pulley body in the axial direction;
• wherein the flange body:
• is positioned in the second end of the pulley body in the axial direction;
• has a second flange that protrudes outward in the radial direction;
• and
• has a fitting recess that is fitted to the fitting protrusion, is hollowed in the axial direction, and has an annular shape,
• the fitting recess has an annular inner surface including, outward in the radial direction, a first inclined surface that has a shape of a side surface of a truncated cone, the first inclined surface being inclined so as to approach the first end of the pulley body in the axial direction as extending outward in the radial direction,
• the fitting protrusion has a distal end surface including, outward in the radial direction, a second inclined surface that faces the first inclined surface,
• the flange body has an inner peripheral surface that:
• is connected to an end portion, outward in the radial direction, of the first inclined surface;
• and faces an outer peripheral surface of the fitting protrusion of the pulley body, the inner peripheral surface serving as a circumferential wall surface of the fitting recess and having one of a protrusion and a recessed groove, which has no end and continues in a circumferential direction, and
• a region including an annular-shaped area between the first inclined surface and the second inclined surface includes a joint portion of a molten resin, which is prevented from moving past the protrusion or the recessed groove, such that when the pulley body and flange body are joined together, weld burrs are prevented from being ejected by one of the protrusion and the recessed groove,
• wherein the cross-section of each of the protrusion and the recessed groove, cut by a plane including a rotation axis, is one of an arc-shape and a trapezoid, the trapezoid having two non-parallel opposing sides.

A method of producing a pulley with two flanges, the pulley including a pulley body made of a synthetic resin and a flange body that is joined to the pulley body in a male-female fitting manner and is made of a synthetic resin, wherein

• the pulley body includes:
• a first flange that protrudes outward in a radial direction perpendicular to a rotation axis, at a first end of the pulley body in an axial direction parallel to the rotation axis;
• and
• a fitting protrusion that has an annular shape and protrudes in the axial direction, at a second end of the pulley body in the axial direction, the flange body:
• is positioned in the second end of the pulley body in the axial direction;
• has a second flange that protrudes outward in the radial direction;
• and
• has a fitting recess that is fitted to the fitting protrusion, is hollowed in the axial direction, and has an annular shape,
• the fitting recess has an annular inner surface including, inward in the radial direction, a first inclined surface that has a shape of a side surface of a truncated cone, the first inclined surface being inclined so as to approach the first end of the pulley body in the axial direction as extending inward in the radial direction,
• the fitting protrusion has a distal end surface including, inward in the radial direction, a second inclined surface that faces the first inclined surface,
• the flange body has an outer peripheral surface that:
• is connected to an end portion, inward in the radial direction, of the first inclined surface;
• and faces an inner peripheral surface of the pulley body, the outer peripheral surface serving as a circumferential wall surface of the fitting recess and having one of a protrusion and a recessed groove, which has no end and continues in a circumferential direction, and a region including an annular-shaped area between the first inclined surface and the second inclined surface includes a joint portion of a molten resin, which is prevented from moving past the protrusion or the recessed groove, such that when the pulley body and flange body are joined together, weld burrs are prevented from being ejected by one of the protrusion and the recessed groove,
• wherein the cross-section of each of the protrusion and the recessed groove, cut by a plane including a rotation axis, is one of an arc-shape and a trapezoid, the trapezoid having two non-parallel opposing sides, the method comprising:
• molding the pulley body through injection molding;
• molding the flange body through the injection molding;
• placing the pulley body molded so that the first flange is placed on a bottom and the axial direction corresponds to a vertical direction;
• placing the flange body molded on the pulley body so that the fitting recess is fitted to the fitting protrusion of the pulley body;
• and
• transmitting ultrasonic vibration of a hone of an ultrasonic welding machine to an inside of the flange body and an inside of the pulley body while pushing the flange body downward by the hone, so as to melt the corner of the pulley body mainly, thereby joining the flange body to the pulley body.

A method of producing a pulley with two flanges, the pulley including a pulley body made of a synthetic resin and a flange body that is joined to the pulley body in a male-female fitting manner and is made of a synthetic resin, wherein

• the pulley body includes:
• a first flange that protrudes outward in a radial direction perpendicular to a rotation axis, at a first end of the pulley body in an axial direction parallel to the rotation axis;
• and
• a fitting protrusion that has an annular shape and protrudes in the axial direction, at a second end of the pulley body in the axial direction,
• the flange body:
• is positioned in the second end of the pulley body in the axial direction;
• has a second flange that protrudes outward in the radial direction;
• and
• has a fitting recess that is fitted to the fitting protrusion, is hollowed in the axial direction, and has an annular shape,
• the fitting recess has an annular inner surface including, outward in the radial direction, a first inclined surface that has a shape of a side surface of a truncated cone, the first inclined surface being inclined so as to approach the first end of the pulley body in the axial direction as extending outward in the radial direction,
• the fitting protrusion has a distal end surface including, outward in the radial direction, a second inclined surface that faces the first inclined surface,
• the flange body has an inner peripheral surface that:
• is connected to an end portion, outward in the radial direction, of the first inclined surface;
• and faces an outer peripheral surface of the fitting protrusion of the pulley body, the inner peripheral surface serving as a circumferential wall surface of the fitting recess and having one of a protrusion and a recessed groove, which has no end and continues in a circumferential direction, and
• a region including an annular-shaped area between the first inclined surface and the second inclined surface includes a joint portion of a molten resin, which is prevented from moving past the protrusion or the recessed groove, such that when the pulley body and flange body are joined together, weld burrs are prevented from being ejected by one of the protrusion and the recessed groove,
• wherein the cross-section of each of the protrusion and the recessed groove, cut by a plane including a rotation axis, is one of an arc-shape and a trapezoid, the trapezoid having two non-parallel opposing sides, the method comprising:
• molding the pulley body through injection molding;
• molding the flange body through the injection molding;
• placing the pulley body molded so that the first flange is placed on a bottom and the axial direction corresponds to a vertical direction;
• placing the flange body molded on the pulley body so that the fitting recess is fitted to the fitting protrusion of the pulley body;
• and
• transmitting ultrasonic vibration of a hone of an ultrasonic welding machine to an inside of the flange body and an inside of the pulley body while pushing the flange body downward by the hone, so as to melt the corner of the pulley body mainly, thereby joining the flange body to the pulley body.