METHOD FOR FORMATION OF CONSTANT PITCH HELICAL SURFACES OF ARTICLES WITH NONCYLINDRICAL CENTER Russian patent published in 1998 - IPC

FIELD: mechanical engineering. SUBSTANCE: screw motion is imparted to article. Tool is rotated and moved away from article axis simultaneously. Producing surface of tool is made as sphere. Tool is moved away from article axis by turning around center of spherical producing surface. In this case, coordinates of cutting edge points for front helical surface must satisfy the following condition: , where m₀ is the shortest distance between axes Z and Z_u, mm; ψ_z is an angle of turn of system of coordinates X_u, Y_u, Z_u about article axis, rad; R_sph is producing sphere radius, mm; r₀ is polar coordinate of cutting edge calculated point, mm; ϕ is polar angle of cutting edge calculated point, rad; Z₀ is coordinate of cutting edge calculated point along axis Z_u, mm; β is half of an angle at top pf part conical center, rad; P is screw parameter p = P/2π, where P is helical surface pitch, mm; X, Y, Z are coordinates of part cutting edge points, mm. Front angles and front helical surface for articles with noncylindrical center and large difference in diameters are obtained by means of one tool having spherical profile. EFFECT: calculation of coordinates X, Y, Z of cutting edge points of article with noncylindrical center. 2 dwg