A machine tool for machining pre-toothed workpieces has a workpiece carrier, a workpiece spindle with a workpiece spindle housing and a workpiece spindle shaft. The machine tool has a meshing sensor, a calibration piece, and a sensor controller which is designed to perform the following procedure: Moving the meshing sensor relative to the workpiece spindle into a calibration position in which the meshing sensor is located at the calibration piece 10; determining a response behavior of the meshing sensor by the sensor controller moving the meshing sensor relative to the calibration piece and meanwhile receiving sensor calibration signals of the meshing sensor, and moving the meshing sensor into a workpiece measuring position in which the meshing sensor is located at the workpiece, the workpiece measuring position depending on the determined response behavior.

This gear cutting machine, which is equipped with a cutter (15), a cutter spindle motor (11) that causes, via a crank mechanism (13) and a cutter spindle (16), the cutter (15) perform a stroke operation, and a motor control unit (10) that controls the rotation angle of the cutter spindle motor (11), is provided with a relieving spindle motor (12) that causes the cutter (15) to move in the direction of a relieving spindle via a link mechanism (four-joint link mechanism (14)). The motor control unit (10) controls the rotation angle of the relieving spindle motor (12) on the basis of the rotation angle of the cutter spindle motor (11). Consequently, a gear cutting machine that accurately controls the relieving operation in accordance with a desired shape, such as crowning and tapering of a gear to be cut can be provided.

The present invention improves the calculation accuracy of the phase of gear teeth. This method for calculating a phase of teeth of a gear, the gear having Z number of teeth, includes: a gear teeth amplitude signal acquiring step of acquiring a gear teeth amplitude signal (S(c)) corresponding to at least one revolution of the gear, the gear teeth amplitude signal (S(c)) being formed by an association of an angle (c) of the gear and a value corresponding to irregularities on an outer circumference of the gear within the angle (c); a phase calculating step of calculating a phase (B) of an angular pitch (P) of the gear in accordance with the number (Z) of teeth when the gear teeth amplitude signal (S(c)) is subjected to frequency decomposition; and a gear meshing angle calculating step of calculating a gear meshing angle on the basis of the phase (B) detected by the phase calculating unit.

A tool which can be used for gear manufacturing machining of a workpiece may be dressed on a dressing machine, and the dressing may take place with line contact between the dresser and the tool. A specific modification of the surface geometry of the tool is produced by the suitable selection of the position of the dresser with respect to the tool during dressing. The specific modification of the surface geometry of the workpiece is specifiable with regard to various parameters.

In a method of producing a toothed workpiece having a modified surface geometry by a diagonal generating method by means of a modified tool, a tool may be used whose surface geometry comprises a modification which can be described at least approximately in the generating pattern at least locally in a first direction of the tool by a linear and/or quadratic function, with the specific modification of the tool producing a corresponding modification on the surface of the workpiece by the diagonal generating method, with the modification of the workpiece produced by the specific modification of the tool having a profile modification and/or a modification caused by a change of the machine kinematics during the machining process of the workpiece superposed on it.

A toothed workpiece having a modified surface geometry may be produced by a diagonal machining method by means of a modified tool. The modification of the tool can be described at least approximately at least locally in the generating pattern in a first direction of the tool by a linear and/or quadratic function; the coefficients of this linear and/or quadratic function are formed in a second direction of the tool which extends perpendicular to the first direction. A pitch and/or crowning of the modification varies in dependence on the angle of rotation of the tool and/or on the tool width position, and a tooth thickness of the modified tool varies in a non-linear manner in dependence on the angle of rotation of the tool and/or on the tool width position.

A toothed workpiece having a modified surface geometry may be produced by a diagonal generating method by means of a modified tool whose surface geometry comprises a modification. The modification may be described by a linear and/or quadratic function, with the coefficients of this linear and/or quadratic function. Pitch and/or crowning of the modification may vary in dependence on the angle of rotation of the tool and/or on the tool width position. The specific modification of the tool produces a corresponding modification on the surface of the workpiece by the diagonal generating method, with a desired modification of the surface geometry of the workpiece being specified and a modification of the surface geometry of the tool suitable for producing this desired modification being determined in combination with a diagonal ratio of the diagonal generating method suitable for producing the desired modification.

A gear machining apparatus causes a machining tool and a workpiece to rotate at a high speed in synchronization with each other to machine a highly accurate gear through cutting. The machining tool is manufactured such that each of pitches between tool blades of the machining tool is an integer multiple of a pitch between teeth of the gear, the integer multiple being equal to or larger than double. By using the machining tool for cutting performed by the gear machining apparatus, the number of the tool blades of the machining tool, which are brought into contact with the workpiece at the same time, is reduced. Thus, it is possible to suppress occurrence of self-excited vibrations during cutting by reducing the cutting resistance. Thus, it is possible to enhance the tooth trace accuracy of the gear.

Device for chamfer machining of a toothed workpiece, wherein the device comprises at least one workpiece spindle having a rotatably mounted workpiece holder for holding the workpiece, and a machining head that is movable relative to the workpiece spindle via at least one linear axis, wherein at least one tool spindle having a rotatably mounted tool holder for holding at least one tool for machining a workpiece held in the workpiece holder is provided on the machining head, and wherein a milling spindle having a rotatably mounted milling cutter holder for holding an end milling cutter for chamfer machining an edge of a toothing of the workpiece held in the workpiece holder is provided on the machining head, wherein the work angle of an end milling cutter held in the milling cutter holder relative to the edge of the toothing can be set via a first pivot axis.

A method of replacing at least one tooth of a gear includes providing a tool jig including a mounting block with a plurality of indexing jig features. The tool jig also includes a tool-supporting feature in laterally movable contact with a jig rail feature. With at least one indexing jig feature, relative motion of the tool jig relative to the gear is resisted. A material-removal tool is operated, while attached to the tool-supporting feature in the tooth-removal position, to remove at least a portion of a working circumference of the gear including a native gear tooth to be replaced. Motion of the material-removal tool is guided to generate a circumferential gear cut including a relatively smooth first cut surface formed by removal of at least the native gear tooth to be replaced. The material-removal tool is removed from the tool-supporting feature. The tool jig is removed from the gear.