Herringbone gears have?

Herringbone gears are characterized by their unique tooth configuration, which includes a pair of angled teeth that resemble a herringbone pattern. This design incorporates two sets of helical teeth that are arranged in a V-shape, allowing for smooth and efficient power transmission. The reason the correct choice refers to "a formed point at the gear center" is that the converging teeth effectively create central loading and engagement points essential for distributing loads and minimizing axial thrust, an advantage of herringbone gears.

To elaborate, the specific arrangement of the teeth means that forces are balanced across the gear, preventing lateral loads that can occur in traditional helical gears and enhancing the gear's operational efficiency and durability. This capability often leads to quieter operation due to reduced vibration and stress on the gear assembly.

In contrast, options that reference straight teeth or minimal teeth in contact do not align with the defining features of herringbone gears, as these gears are specifically designed to maximize the contact area and engagement of the helical tooth profiles to improve performance.