The goal of this research is the practical application of self-adhesive gears made of 100% bamboo fiber without any chemical treatment. Bamboo is placed on a machining center, and vascular bundles are extracted as bamboo fiber by end-milling along the distribution of vascular sheaths, leaving lignin-containing parenchyma cells around the vascular bundles. By eliminating any chemical treatment, an environmentally friendly molded product made of 100% bamboo is expected.

The extracted bamboo fibers were poured into a mold and heated and pressurized using a small heat press to form bamboo fiber bevel gears. Bamboo fiber bevel gears can be manufactured by self-adhesion of bamboo fibers in the mold through the reaction of lignin contained in the parenchyma cells of the bamboo fibers by heating and pressurizing.

A brushless DC motor was used for the drive side motor part and a torque motor for the driven side as a power absorption type driving system.

To quantitatively evaluate the dynamic characteristics of the gear pair during driving, tooth root strains were measured at three locations on the drive side: the center of the tooth root, the outer edge of the tooth root, and the outer end plate.

It was found that the tooth root strain increased with the progress of meshing at the center and outer ends, while it slightly decreased with the progress of meshing at the outer end plate.

The maximum tooth root strain increased exponentially at the center and outer ends, and the amount of change was almost equal. The amount of change in the outer end plate also increased exponentially, but the change was smaller than that of the center and outer end plates. It was also found that the outer end plates are also responsible for torque transmission.

The actual meshing ratio was calculated based on the tooth root strain, and the actual meshing ratio was found to be 1.03, indicating that the teeth are meshing with a single tooth.

Red paint was used to visualize tooth contact. The tooth contact was found to increase toward the outer end and toward the tooth tip as the applied torque increased. These changes are considered to be due to the bending deformation of the gear shaft in addition to the increase in tooth deflection of the bamboo fiber gear.

The transmission efficiency was calculated from the driving torque and driven torque for each load torque. It was found that the transfer efficiency was small in the range of small load torque, and that the transfer efficiency also increased as the load torque increased. This is thought to be because the increase in torque loss is small compared to the increase in load torque, resulting in a larger transfer efficiency.

"Investigation of Tooth Meshing of Natural Fiber Bevel Gears Composed of Only Bamboo Fibers Extracted Using a Machining Center"

Paper Type