Research on Impact Stress Transfer Characteristics of Lunar Rock Coring Drill

Table 2

The constraint parameters of the percussive mechanism.

Parameter name	Symbols	Value interval	Optimum result
Spring stiffness coefficient	kP	＜20000	13500 N/m
Hammer amplitude	hC	5, 6, …, 20	8 mm
Spring preload displacement	hP0	5, 6, …, 20	20 mm
Hammer mass	mP	180, 280, …, 580	180 g
Number of convex contour line bumps	nCb	2, 3, 4	2
Cam thrust motion angle	βC1	10, 55, …, 180	155°
Cam base circle radius	RC	25, 26, …, 35	33 mm

Optimum indexes: percussive frequency f_P = 20 Hz; single impact energy W_P = 2.6 J. Constraint parameters: cam speed n_C < 3000; roller equivalent rolling friction coefficient R_Cf = 0.0039; sliding friction coefficient μ_C = 0.5; permissible pressure angle (α_C) < 20.