Cutting method using a scraping-cutter for involute conjugate gears including face gears

Introduction

We are currently investigating gears conjugated to involute cylindrical gears. Our research shows that a gear that meshes with an involute cylindrical gear has a straight line of action, and the meshing point moves at a constant speed. These gears transmit rotational angles at a constant speed. The meshing-contact-line-of-action exists continuously in space and constitutes the meshing contact surface of action. The curve formed when the meshing-contact-surface-of-action intersects with the tooth surface of the face gear is the simultaneous contact line between the pinion and face gear. [1]
The involute cylindrical gear and its conjugate gear, which are the rotation axes that mesh with each other in any positional relationship, can be defined using the shaft and crossed angles. We proposed that conjugate gears that mesh with involute cylindrical gears with freely set shafts and crossed angles may be widely applicable in numerous fields. Furthermore, we have confirmed that they mesh at a constant speed along a straight line of action and established a unified theory.[2]
In the unified theory, face gears are considered a type of gear that conjugates with involute cylindrical gears. Using the unified theory, the meshing mechanism of the external cylindrical gear pair from the face gear to the internal gear can be explained using the meshing-contact-line-of-action. Furthermore, the appropriate parameters required for the tooth surface design of conjugate gears can be obtained.

Proposed new cutter

The existing methods for machining involute conjugate gears include shaper, machining, special hobs, 3D-printers and gear skiving. We proposed a method for machining face gears using scraping -cutters. This method uses a simple shaft configuration and cutter tooth profile. If these conditions are met, face gears can be produced efficiently and with high precision.
The proposed method aims at to match helical gears and conjugate involute gears. The tooth profile of the cutter is a spur gear with the same involute curve as that of the involute helical gear in the transverse section axis. In this process, the tooth edges of the tool are used to scrape the tooth surface of the face gear. The positional relationship between the tool and face gear during machining is shown in Figure 1.

The tool was located on the same rotation axis as the pinion and fed axially while rotating synchronously with the face gear base material. This transverse section, the cutter tooth profile has the same involute curve as that of the pinion, but the tooth thickness is smaller. When the cutter and face gear are rotated synchronously, edges of the cutter come into contact with the base material of the face gear.
The cutting point of the cutter was moved to trace the pinion tooth profile.
The point of meshing contact between the pinion and face gear can be obtained using the theory of the mesh contact line of action. The trajectory of the cutting point created by the cutter can be obtained by adding a parameter representing the axial feed of the cutter to this meshing point.

Prototype Making

Here, we present prototype examples of face gears fabricated using scraping -cutters. Figure 2 shows the created scraping -cutter, which was made of high -speed -steel. In addition, by tilting the shaft angle of the scraping cutter, we prototyped outer and inner bevel-shaped conjugate gears that meshed with the involute cylindrical gear.