Power skiving pressure angle correction without tool geometry change
Cutting blade pressure angle changes or corrections in power skiving cutters ( 20 ) can be realized without the need tor a tool geometry change. An axial shift ( 26 ) of the blade reference point ( 24 ) will shift the existing involute on the blade profiles ( 22, 23 ) into a different radial location. An accompanying shift (AR) of the reference involute profile ( 30 ) by approximately the same amount and in the same direction will re-establish the relationship between work gear and cutter. The resulting work gear geometry has the same radial location of the slots, with the same slot width and the same tooth thickness but with a changed pressure angle.
1. A method of changing the pressure angle of the teeth of a gear produced by power skiving with a cutting tool having a periphery and a plurality of stick-shaped cutting blades located about the periphery of the cutting tool, said method comprising:
providing said cutting tool having an initial radial position of said cutting blades,
providing a first gear having an initial pressure angle, a radial location of tooth slots, a tooth slot width and a tooth thickness,
said first gear being formed by power skiving with said tool having said initial radial position of cutting blades, said power skiving being carried out at a first center distance between said first gear and said cutting tool,
changing said initial radial position of said cutting blades by an amount (Y) to an adjusted radial position,
changing said first center distance between said first gear and said cutting tool by an amount (ΔR) to an adjusted center distance,
forming a second gear by power skiving with said tool having said adjusted radial position of cutting blades, said power skiving being carried out at said adjusted center distance between said second gear and said cutting tool,
wherein said second gear comprises teeth having a pressure angle different than said initial pressure angle of said first gear, said second gear having a radial location of tooth slots, a tooth slot width and a tooth thickness the same as said first gear.
2. The method of claim 1 wherein the center distance change (ΔR) is approximately equal to the change in radial position (Y).
3. The method of claim 1 wherein said power skiving comprises hard power skiving.
4. The method of claim 1 wherein changing said initial radial position of said cutting blades comprises shifting the position of each of said plurality of cutting blades in the lengthwise direction thereof.
5. The method of claim 1 wherein said first gear is a theoretical reference gear.
6. The method of claim 1 wherein said first gear is formed from a first workpiece blank and said second gear is formed from a second workpiece blank, and wherein said first and second workpiece blanks are identical.