A gear blank is provided. It includes a disk having a first face and a second face. A first plurality of individual lugs formed on said first face circumferentially adjacent an outer circumferential edge of said disk. Each lug of said first plurality of individual lugs has a first inner circumferential edge formed on said first face along a first retaining diameter. Adjacent lugs of said first plurality of individual lugs have a first circumferential spacing therebetween.

Provided is a method for manufacturing a rotary power transmission member including a ring-shaped main body part fixed to a rotating shaft, and a ring-shaped gear part formed on an outer circumference part of the main body part to transmit rotational force of the rotating shaft to other members. The method includes gear part molding for injecting a high melting point resin into a first mold to mold the gear part, and main body part molding for injecting a low melting point resin to mold the main body part while the gear part being inserted into a second mold. The first mold includes a runner defined on an inner circumference side of a ring-shaped cavity for molding the gear part, and a gate which communicates the runner with the cavity to supply a resin into the cavity.

An injection molding resin gear includes: a tooth portion having teeth formed on an outer peripheral portion thereof; a shaft supporting portion formed around a center of rotation; and a web that connects the tooth portion and the shaft supporting portion, wherein the web includes a concave and convex portion having a concave portion formed on a first surface and a convex portion formed on a second surface formed at a position corresponding to the concave portion, and one of the concave portion or the convex portion of the concave and convex portion includes a gate point, and the concave and convex portions include a thinned portion at radial end portion in a radial cross section passing through the center of rotation of the concave and convex portion.

Carbodiimide is added to a molten polyamide resin so as to provide resin pellets. The percentage of residual unreacted carbodiimide to each resin pellet is 0.03% to 0.33% by mass. Manufacturing molded articles using the resin pellets achieves both of an improvement in mechanical strength and an increase in wear resistance, and reduces property variations among the molded articles.

A worm wheel is provided in which a step is not formed near a tooth face meshing with a worm, and noise does not easily occur during power transmission. A worm wheel 1 includes a circular arc-shaped tooth section 5 that is a portion meshing with a worm 101 and configuring a circular tube worm gear, and a helical tooth section 4 that is connected to one end side of the circular arc-shaped tooth section 5. An angle of torsion at an arbitrary reference point 14 in a tooth depth direction of a tooth 3 on a boundary 7 between the circular arc-shaped tooth section 5 and the helical tooth section 4 is equal to an angle of torsion at a second reference point 15 corresponding to the first reference point 14 in the tooth depth direction of the tooth 3 in a diameter portion P0 of a throat of the circular arc-shaped section 5. As a result, a step is not formed on a tooth face on the boundary 7 between the circular arc-shaped tooth section 5 and the helical tooth section 4. A tooth face of the circular arc-shaped tooth section 5 and a tooth face of the helical tooth section 4 are smoothly connected.

The invention relates to a method for producing a gear, said method including a step (a) during which a supporting core is made from a first polymer material, said supporting core comprising a hub, with a director axis (XX), as well as a flange which extends radially from said hub to a peripheral flanged edge, said method then involves a coating step (b) which comprises producing a permanent coating layer, made of a second polymer material, by overmoulding on the supporting core, including integrally both a front layer which covers the upper surface of the flange, and a side layer which extends said front layer axially by covering the outer radial surface of the flanged edge, such that said side layer forms a rim, the teeth of the gear being made in the radial body of said rim.

A vent structure includes: a first housing component having an opening portion for ventilation; a gas-permeable membrane that is attached to the first housing component to close the opening portion; and a laser welding portion that joins the first housing component with the gas-permeable membrane. The gas-permeable membrane includes a main body including a fluororesin film and a porous resin sheet that is laid on the main body. The porous resin sheet is located on the surface side of the vent structure. Both of the main body and the outer peripheral portion of the porous resin sheet that projects outwardly from the main body are fixed to the first housing component by the laser welding portion.

A bicycle cogset manufacturing method includes: connecting a first and a second sprocket in different sizes with connecting members as a sprockets assembly in advance, where first and second inner portions of the first and second sprockets respectively have first insertion and second insertion members, and each of the insertion members are respectively provided with a first and a second positioning hole; transferring the sprockets assembly into a mold, and performing pouring to form a sprocket base, where an assembly hole is disposed in the center of the sprocket base, a plurality of connecting arms are arranged on an outer portion of the sprocket base, and the connecting arms clad the first insertion members and the second insertion members to form a cogset. In this way, modularization can be implemented to achieve objectives of preventing troublesome riveting, accelerating manufacture, and reducing product weight.

A gearwheel has an insert portion made of metal and an outer portion made of plastic, where the outer portion has a toothed rim and the outer portion is injection-molded onto the insert portion. The outer portion has a plurality of injection-molded sections formed on a side surface of the insert portion which surface is directed transversely or perpendicularly to the central longitudinal axis. To produce the gearwheel inexpensively and with sufficiently good physical properties as regards its load-bearing capacity and its useful life. The gearwheel is characterized in having injection-molded sections spaced apart from one another on the side surface of the insert portion and side surface areas of the insert portion are left free between directly adjacent injection-molded sections.

An axle for rotatably supporting a rotating object having a circular hole therein, such as a gear. The axle includes a shaft and an enlarged head having slits dividing the enlarged head into a plurality of sections, such as three. The enlarged head is tapered to enable pressing the rotating object thereagainst to deflect the sections inwardly, so that the rotating object passes over the enlarged head into encircling engagement with the shaft. The enlarged head is fabricated from a material sufficiently elastic to enable the three sections to be constricted to enable the rotating object to be slid past the enlarged head, and to be entrapped upon spontaneous expansion of the enlarged head when the rotating object has cleared the enlarged head.