Provided is a spur gear component including a plurality of teeth protruding in a radial direction, extending in an axial direction, and arranged at equal pitches in a circumferential direction, the spur gear component including a fiber material having a shape corresponding to an arrangement pattern of the plurality of teeth and wound in a spiral shape around a center axis.

This gear wheel mechanism includes a rotator, a first gear wheel, a second gear wheel, and a reinforcement member. The rotator is configured to be rotatable about a rotation shaft and has an elliptical shape as viewed in an axis direction of the rotation shaft. The first gear wheel includes a first base portion including a first outer circumferential surface and a first inner circumferential surface and having a hollow cylindrical shape configured to be deformable by the rotator being inserted in the axis direction of the rotation shaft and external teeth formed in the outer circumferential surface. The second gear wheel includes a second base portion including a second outer circumferential surface and a second inner circumferential surface and having a hollow cylindrical shape disposed to cover the external teeth and internal teeth which are formed at positions facing the external teeth of the second inner circumferential surface, with which the external teeth are partially engaged in accordance with deformation of the first base portion by rotation of the rotator. The reinforcement member is disposed in contact with a region of the second outer circumferential surface corresponding to a region in which the internal teeth of the second inner circumferential surface are formed.

In the primary molding step, the insert core having axially-projecting convex portions aligned apart from one another in the circumferential direction is located in a primary molding die, and the injection molding is performed. In the secondary molding step, the annular internal resin member and the insert core which have undergone the primary molding step are located in a secondary molding die, and the injection molding is performed. Gates for injecting molten resin in a cavity of the secondary molding die are located in the secondary molding die so that welds that are joining points of the molten resin in the secondary molding step are positioned in the radially outside of rib portions.

The method for manufacturing the worm wheel includes a step of combining the first molds for molding the first tooth surfaces of the wheel teeth to be pushed by the shaft tooth when the worm shaft rotates in the direction and the second molds for molding the second tooth surfaces of the wheel teeth to be pushed by the shaft tooth when the worm shaft rotates in the direction to form the cavities defined by the first molds and the second molds, a step of injecting the molten resin into the cavities to mold the wheel teeth, and a step of separating the first molds and the second molds from each other in the direction oblique to the tooth traces of the wheel teeth.

A resin molding mold, by which a resin worm wheel for a worm speed reducer is molded, includes a plurality of tooth forming portions provided such that the tooth forming portions are disposed at predetermined intervals on a circumference of the resin molding mold. The tooth forming portions each include a projection portion provided in a part of a tooth-flank forming surface by which a tooth flank is formed.

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.

Provided is a method for producing a gear including an intermediate product forming process of solidifying a fluid material to form a gear intermediate product, and a tooth forming process of cutting the gear intermediate product to form teeth.

In the primary molding step, the insert core having axially-projecting convex portions aligned apart from one another in the circumferential direction is located in a primary molding die, and the injection molding is performed. In the secondary molding step, the annular internal resin member and the insert core which have undergone the primary molding step are located in a secondary molding die, and the injection molding is performed. Gates for injecting molten resin in a cavity of the secondary molding die are located in the secondary molding die so that welds that are joining points of the molten resin in the secondary molding step are positioned in the radially outside of rib portions.

An inner wheel element (15a) is embedded in an outer wheel element (16a), such that a continuous range from an inner diameter side circumferential surface configuring an inner surface of a first annular concave part (22), through an outer circumferential surface of the inner wheel element (15a), to an inner diameter side circumferential surface configuring an inner surface of a second annular concave part (38) in a surface of the inner wheel element (15a) is covered over the entire circumference. Accordingly, a structure is achieved which easily secures a holding power of the synthetic resin outer wheel element with respect to the inner wheel element.

A method for producing a ring gear for a planetary gear train, wherein a continuous profile is produced by an extrusion process and the continuous profile is subsequently cut to a predetermined cutting length in order to form a ring gear body.