PSI - Issue 80

Seiji Mitsubayashi et al. / Procedia Structural Integrity 80 (2026) 431–442 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

433

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After uniform dispersion of the short fibers, the curing agent was added to the base resin at a ratio of 3:1 (resin to curing agent) and gently stirred with a spatula to minimize void formation, resulting in the preparation of the BMC. Before pouring the BMC into the mold, the carbon fiber cloth was manually positioned along the tooth surface using a pointed wooden tool to press it in place. To examine the influence of the number of cloth layers on mechanical strength, two gear types were prepared: one with a single layer and another with two layers of cloth placed along the tooth surface. Gears were fabricated with chopped fiber contents of 0.2, 0.4, 0.6, 0.8, and 1.0 wt%. During curing, a weight was placed on the upper mold plate to apply pressure to the resin. The curing process was conducted under the conditions of 90 °C, 4.2 kPa, and 2 hours. The applied pressure helped expel excess resin and is expected to direct the compounded fibers toward the tooth tip. To evaluate the effect of pressure on strength, additional gears were fabricated without the use of a weight. Moreover, CFRP gears incorporating a metallic insert were also prepared. Figure 2 shows the dimensions of metallic insert.

Fig. 1. Schematic diagram of the CFRP gear.

Fig. 2. Dimensions of metallic insert.

Table 1. Specifications of CFRP gears. Parameter

Values

Module

3

Number of teeth

20 15 15 20

Width [mm]

Diameter of shaft hole [mm]

Pressure angle[deg]

Accuracy grade

JIS B 1702-1