Maag Gear-wheel & Machine Company Limited

Peter Bloch

Robert Wydler

Meinrad Donner

Hansjorg Bickel

Roman Schwaighofer

Rudolf Fischer

Erwin J Gunter

Otto Schneider

For machining the tooth flanks of a hardened workpiece having pre-formed teeth two cutting blades or plates are secured to a cutting blade or plate holder. The cutting blades or plates are provided with a base member or backing formed of a hard metal and a cover layer sintered thereon which is formed of cubic boron nitride. Each cutting blade forms a cutting surface and a clearance surface. Each individual cutting blade or plate is arranged at the cutting blade or plate holder in relation to the direction of the intended cutting movement such that the surface of the cover layer forms the clearance surface and an end face or surface of the cover layer is located in the cutting surface. Consequently, there is achieved the result that the cutting surface can be reground in the same manner as tools which, for example, are made of hardened steel and which are not provided with a cover layer.

Tool for machining tooth flanks and method of finishing tooth flanks

A doubly dished or double-cone grinding wheel or a pair of singly dished or single-cone grinding wheels are reciprocated in strokes along the tooth flanks or a helically toothed gear wheel to grind the gear. The stroke motion is controlled in dependence of measured values of the generating motion and of the momentary position of the grinding wheel or wheel pair upon the tooth flank being ground. For this purpose, a grinding reference polygon determining the grinding stroke limits is constructed from the gearing specifications or data. An effective grinding point of the grinding wheel or wheel pair is then determined at short time intervals from measurements of the momentary generating and stroke position of the machine. The spacing of this effective grinding point from the subsequent grinding stroke limit in the grinding stroke direction is determined. Finally, the grinding stroke motion is controlled in its path and speed such that it reverses at each grinding stroke limit defined by the grinding reference polygon.

Method for controlling a grinding stroke in a gear tooth flank grinding

In order to eliminate undulation errors in gear production wherein a generating motion of a gear-tooth flank of a gear fixed to a rotary table corresponding to an involute profile is induced by simultaneously imparting a predetermined rotary motion and a predetermined translatory motion to the rotary table, a reference ratio of these two speeds is determined, the momentary speeds of the table are measured and a momentary ratio is determined therefrom. A difference value is formed between the reference ratio and the momentary ratio. This difference value is first formed for each gear-tooth flank during one revolution and then stored in association with the momentary generating position of the gear and with the momentary stroke position of the gear-fabricating tool and only when the same gear-tooth flank is reached during a further revolution is the adjustment value of the gear-fabricating tool corrected by means of the stored difference values.

Method and apparatus for eliminating undulation errors on gear-tooth

In a gear tooth flank grinding machine operating on the indexing generating principle, a pair of dished grinding wheels is moved back and forth along the generatrices of involute gear tooth flanks, the grinding stroke being longer than the length of the generatrices by the amount of a supplemental dimension. The effective radius of at least one grinding wheel is measured at least once during the machining of each gear tooth flank and the grinding stroke is reduced in correspondence to the gradual reduction of the measured radius.

The grinding wheel is axially displaceable by means of an axial drive for material removal or cutting operations and tooth flank corrections. The axial drive comprises a double-acting hydraulic piston-cylinder unit, the piston of which is formed at a spindle sleeve of a grinding wheel spindle and the cylinder of which is formed in a carrier or support sleeve. The cylinder is controllable by a servo-valve. A displacement or path measuring device is operatively associated with the spindle sleeve. The servo-valve as well as the displacement or path measuring device are connected to a displacement or path detection circuit which is connected to a program or operating control. There is thus realized a particularly sensitive and precise adjustment for the material removal or cutting operations and the tooth flank corrections.

Gear grinding machine including a double-cone shaped grinding wheel

The generating method is accomplished at a machine containing one or two tools, constructed to possess a disk, cone or double-cone configuration, which are moved to-and-fro in a stroke-like fashion along the tooth flanks and can be advanced in the direction of the tooth flanks and act at one or two work locations upon a respective tooth flank. The displacement of the tool or each tool needed for producing the profile and longitudinal corrections is determined for each work location at the field of action or engagement zone of the teeth and is controlled as a function of the generating position and the stroke position of the machine tools according to predetermined functions.

Generating method for the chip-producing machining of involute tooth

An indexing generating method for grinding gears having an involute-shaped tooth flank profile, wherein there are accomplished between a dished or plate-shaped grinding wheel and the gear teeth to-and-fro generating movements as well as feed or advance movements in the tooth lengthwise direction, adjustment movements for compensating for the wear of the grinding wheel, and, finally, indexing movements. The grinding wheel is advanced between two respective indexing movements, independently of the magnitude of the adjustment needed for compensating for wear of the grinding wheel, by such an amount towards the tooth base or bottom land that also such tooth base is ground.

Indexing generating method for grinding gears

An apparatus for grinding gears having an involute-shaped tooth flank profile, wherein there are accomplished between a dished or plate-shaped grinding wheel and the gear teeth to-and-fro generating movements as well as feed or advance movements in the tooth lengthwise direction, adjustment movements for compensating for the wear of the grinding wheel, and, finally, indexing movements. The grinding wheel is advanced between two respective indexing movements, independently of the magnitude of the adjustment needed for compensating for wear of the grinding wheel, by such an amount towards the tooth root that also such tooth root is ground.

Apparatus for grinding gears

A gear tooth profile testing apparatus has a pair of displaceable measuring devices, one of which is movably mounted on an adjustable base plate and has the other device movably mounted on it. A probe mounted on said other device has biassing means urging it against the profile under test. Drive means displace one of the devices, which transmits signals of relative movements between the two devices to a computer. The computer receives from the other device signals of its movements relative to the base plate. The computer compares these measurements of probe movement with reference values to evaluate deviations in the measured profile.

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Mutschellen, Switzerland

Peter Bloch