US 4,663,721 A · Gear cutter

Abstract

A method and control system for gear cutting machines such as hobbing equipment, shaper cutters and bevel-cutting equipment for achieving greater accuracy, productivity, and gears of increased quality while eliminating error, tedious calculations, labor and product variation is provided by employing a control system and utilizing a method of gear cutting wherein optimum cutter efficiency is maintained by electronically monitoring and controlling cutter input power, cutter shift and workpiece feed or in an alternative embodiment by varying index drive and feed drive in response to inputs measured from the cutter or cutter motor to produce gears approaching the optimum theoretical calculated configuration. The computer and control system can be readily adapted to existing gear cutting machines by utilizing an alternative embodiment of the invention which adds an encoder to the main cutter motor and replaces existing mechanical linkages for feed and index with variable speed electric motors and encoders to provide computer controlled index and feed rates that may be varied substantially instantaneously with the cutting of each gear tooth to maintain a predetermined cutter program. The method of cutting gears and the control system provides for the production of more accurate gears by eliminating the use of cams in shaper cutters and the use of change gears in hobbing machines and by properly controlling hob shift to result in an increased hob cutter lift and provide higher production of optimally designed gears.

Claims21

Dependent claims

An apparatus for cutting gears of increased accuracy comprising:

(a) an electrically activated cutter including encoding means to provide pulses corresponding to information on cutter speed;
(b) a first electrically activated variable speed motor to provide feed and means for measuring units of power expended to provide feed drive for said gear;
(c) a second electrically activated variable speed motor to provide index drive and means for measuring units of power expended to provide index drive for said gear;
(d) means for electronically comparing and correlating said units of power actually expended for feed drive and index drive with said pulses corresponding to said information on cutter speed wherein said means for comparing and correlating includes predetermined units of power ideally or previously expended in cutting a gear of a predetermined design;
and
(e) means for electronically increasing or decreasing said units of power actually expended for said feed drive and index drive in response to said information of cutter speed obtained from said encoding means to operate said cutter during the cutting of said gear and in response to electrically compared predetermined values of units of power required to duplicate said gear of a predetermined design.

3 more elements

A method of cutting gears to provide a gear tooth profile approaching the calculated profile comprising:

(a) cutting a gear with an electrically activated cutter drive having sensor means for providing information on cutter power, angular rotation or a combination thereof;
(b) operating an electrically activated variable speed motor to provide feed drive and measuring units of angular rotation or power expended or a combination thereof required to provide feed drive for said gear;
(c) operating an electrically activated variable speed motor to provide index drive and measuring units of angular rotation or power expended or a combination thereof required to provide index drive for said gear;
(d) electronically comparing and correlating said units of angular rotation or power or a combination thereof actually expended for cutter drive, feed drive and index drive with predetermined values of angular rotation or units of power or combination thereof ideally or previously required to cut a gear of a predetermined design;
and
(e) electronically increasing or decreasing said units of angular rotation or power or a combination thereof actually expended for said feed drive and index drive or a combination thereof in response to information on cutter power, angular rotation or a combination thereof obtained during the cutting of the gear and in comparison to predetermined values for units of angular rotation or power or a combination thereof required to duplicate said ideal gear.

3 more elements

A gear cutting machine for cutting gears of increased accuracy comprising:

(a) a main electric motor for driving the gear cutter and means for providing pulses corresponding to the speed of said main electric motor;
(b) a variable speed electric motor to provide index drive and means for measuring units of angular rotation or power expended or a combination thereof to provide index drive;
(c) a variable speed electric motor to provide feed drive and means for measuring units of angular rotation or power expended or a combination thereof to provide feed drive;
(d) means for electronically comparing and correlating said units of power actually expended by said variable speed electric motor to provide index drive and said variable speed electric motor to provide feed drive with said pulses from said main electric motor wherein said means for electronically comparing and correlating includes predetermined units of power ideally or previously expended in cutting a gear of a predetermined design;
and
(e) control means for electronically increasing or decreasing said units of power actually expended by said variable speed electric motor to provide index drive and said variable speed electric motor to provide feed drive in response to the pulses corresponding to the speed of said main electric motor during the cutting of said gear and in response to electrically predetermined values of units of power required to duplicate a gear of a predetermined design.

3 more elements

Dependencies are inferred from the claim text.

Gear cutter

Life of this patent

Gear cutter

Life of this patent

Abstract

Claims21