Molded resin gear, moded resin rotaor and molded article

Abstract

An injection molded resin gear 1 includes a rim 4 , a hub 3 and a web 5 which connects the rim 4 to the hub 3 . A plurality of ribs 7 for guiding a molten resin, which is injected from pin point gates 8 , to the hub 3 protrude from the outer periphery of the hub 3 on one side of the web 5 so as to correspond to the pin point gates 8 . The ribs 7 are formed so as to be recessed from the side face 10 of the hub 3 . In the connecting portions of the ribs 7 to the hub 3 , fillet portions 12 are formed for smoothly guiding the flow of the resin from the hub 3 toward the web 5 when the injection molded resin gear 1 is formed.

Description

technical field [0001] The present invention generally relates to resin gears used in power transmission devices such as those used in precision instruments such as color copiers, color printers, and video tape recorders, various automatic parts, industrial equipment, and the like. Specifically, the present invention relates to a resin gear formed by injection molding. The present invention also relates to an injection-molded resin gear and an injection-molded resin rotating body such as an injection-molded resin roller or an injection-molded resin pulley. In addition, the present invention relates to an injection-molded article or a static shaft supporting member used as a dynamic rotating body such as an injection-molded resin gear or an injection-molded resin roller. Background technique [0002] For example, a tandem color copier and a color printer are arranged to sequentially perform the steps of forming black (K), red (M), cyan (C) and yellow (Y) Image, to successiv...

AI Technical Summary

Problems solved by technology

[0008] However, if the resin is obtained from such Figure 17 If the three pinpoint gates 35 shown are injected into the cavity, as shown by the arrows, the resin injected from each pinpoint gate 35 will mutually flow in the substantially middle portion between the adjacent pinpoint gates 35, 35. Inflow thereby creating weld lines 36, which creates problems that not only weld lines 36 negatively affect the accuracy of the tooth profile, but they also negatively affect the strength of the gear

Like this, the axial mold 56 that is used to form an axial hole 55 cannot be firmly supported on one side of the upper mold 57, and the axial mold 56 can move easily due to injection molding pressure, so there will be such a problem, that is, injection molding The shaft hole 55 of the molded resin gear 51 is easily off-centered, thereby adversely affecting the measurement result of the deviation of the top circle

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