The development of hob of hard alloy scrape

Right razor blade 2.

Cutter hub 3.

Left razor blade 4.

Bit 5.

Rubber pays a figure the hob of the structure that mount a tooth-like part of anything of 1 hob by cutter hub, razor blade, hard alloy razor blade and stretch clamping unit (rubber is filled up) composition (the 1) that be like a graph. Cutter hub is involute worm, mill goes out above edge worm a few narrow groove, groovy number is hob double what circumferential tine counts. Left, right razor blade crisscross enchases felt at worm two side surface, bit go up to also want to machine a chamfer, with will put bit, make bit locates directly go up in involute helicoid. The flexibility that uses rubber mat compresses quantity clamp razor blade, what rubber fills up is flexible make bit can appreciably swings, bit differs as what get force point stick the worm that leans in different position apparently, make actual cutting dot and academic cutting drop consistent, avoided design and the error that assemble a likelihood to arise. Because the cutting surplus of scrape hob is very small, bit gets power lesser, and the action of cutting force is press bit to fixed position face, pass experiment test and verify this structure is reasonable, feasible. 2, bit design and computational graph 2 left razor blade graph 3 razor blade goniometer calculates graph razor blade the effect that has bearing bit, to make bit as better as cutter hub land cooperates, design bit by hob cutter hub. To in an attempt to shows left bit 2 times for exemple, banking angle of the dihedral angel of calculating board and key, end face, bottom carries pointed part. Choose groove is computation on the right side of cutter hub fiducial, set its and cutter hub axial to slant sectionally a value for E, with slant a planar cut involute helicoid, get two curves, the A of tooth form horn that begs a left curve to go up in cent circle is left, use bit of computation of spherical triangle formula next each angle. It is by the planar abbreviation that produces line and edge parallel composition board, the planar abbreviation that comprises by edge parallel and axial line is key. If O is on the right side of groove is in a bit on reference circle, set what OA expresses involute helicoid to produce a line, OB represents axial line, OC is as parallel as edge linear (the 3) that be like a graph, 3 make 3 horn that are acme with O and planar part point-blank. The included angle that produces line and axial line is E=bb of basic circle helix angle, axial line and edge parallel included angle are F=90 ° - A is left, know by involute helicoid property, the happening that produces line and axial line composition face and the plane that produce line and edge parallel composition are perpendicular, happen namely face and board the ° of dihedral angel D=90 between, board and dihedral angel L can press type gets between key: The bit that Sinl=sindsine/sinf becomes by axial line and board top group end face tilts, h of its banking angle is end face and board the dihedral angel between, if P dot is on the right side of the node of groove and reference circle, can choose 3 wiring harness, PA board top line, PB axial line, PC edge parallel, board already got with the dihedral angel L of key, can decide by the structure board top line and ° of S=90 of edge parallel included angle, the type below the basis begs horny H: Ctgfsins=cosscosl+sinlctgh razor blade underside and worm cylinder are tangent, bit Q of end end pointed horn is board the included angle of bottom line and edge parallel, but 3 following wiring harness beg have the aid of piece, board bottom line QA, axial line QB, edge parallel QC, end pointed horn is in by of end panel umbriferous, it is the dihedral angel G with the underside that axial line and board bottom group become and axial line and edge parallel planar composition, can get through geometrical relation, underside and board the dihedral angel W between calculates by undermentioned formula: Cosw=-cosgcosl+singsinlcosf recycle formula begs Q: Sinq=singsinf/sinw right razor blade design calculation method and left razor blade identical. Graph 4 teeth shape error 3, cutting experiment razor blade felt arrives on cutter hub, still need to worry bit end face and flank, diameter is in a circle achieves set dimension, flank should compare bit low about 0.

2mm. Choose cut off knife razor blade commonly, by treatment the requirement is ground in the blade outside body piece reasonable hind horn, the parallelism of the ply of bit and cutting blade and bit underside should satisfy a requirement. Experiment to undertake on gear-hobbing machine Y31125E, cutting speed 32.

06m/min, feed 3.

08mm/r, cutting ply 0.

11mm, in order to arrange mill means cutting, bit material YG8, 40Cr of cutter hub material. The horn before hob carries blade on the head - 20 ° , the horn after side edge chooses 6 ° ; . External diameter 162mm, bore diameter 50mm, length 120mm, circumferential tine is counted 9, by cutting gear parameter; Modulus 10, tine is counted 23, material 45, tooth flank hardness 50 ～ 52. Teeth shape error detects the curve is shown 4 times like the graph. Cutting experiment makes clear, boil cut a course smoother, bit is not had fall off, collapse blade phenomenon, the cutting tool structure that shows a design is reasonable and feasible. CNC Milling