Bevel Gear Strength Calculation According to Merrit

Based on the fixed end beam calculation. Anticipates that the total circumferential force can only be carried by one tooth. Adds an extra contact check.

Allowable load

F all = π c min b w ζ m en μ≥ F t

where:

	c_min= min (c_b, c_c)	minimum tooth allowable stress
	b_w	operating facewidth
	m_en	normal module at end (normal diametral pitch at end inverse value)
	μ	factor of dependence on the precision degree (material property)
	F_t	circumferential force acting on the teeth
		width factor
	where:
		K = 1.4 for straight teeth, 1.25 for helical teeth

Safety factor

S = F all / F t

Bending factor

where:

	σ _Ab	allowable stress in bending (material property)
	r_b	speed bending factor (table value)
	y_b	shape bending factor (table value)

Contact factor

where:

	σ _Ac	allowable stress in contact (material property)
	r_c	speed pressure factor (material property)
	y_c	shape pressure factor (material property)
		size factor