A coating film has a lamination unit including a first layer and at least one of a second layer and a third layer. The first layer is a nitride or the like of a first material represented by (Cr.sub.1-a-b-cAl.sub.a[Ni.sub.1-dZr.sub.d].sub.bX.sub.c). X is at least one element selected from Ti, Nb, Si, B, W, and V. a, b, c, and d represent atomic concentrations. The second layer is a nitride or the like of the second material represented by (Al.sub.cCr.sub.1-e-fZ.sub.f). Z is at least one element selected from Si, Y, and B. e and f represent atomic concentrations. The third layer is a nitride or the like of the third material represented by (Al.sub.gCr.sub.1-g).

The invention relates to a method for producing tooth flank modifications on toothing of workpieces, in which the workpiece and a tool are moved relative to one another and, as a result, material is removed from the tooth flank (3) of the workpiece. Different tooth flank modifications are generated on teeth (1) of the workpiece by means of a continuously rolling manufacturing process, by the tool comprising individually different tool profile geometries which generate the different tooth flank modifications on the teeth (1) of the workpiece. The tool can be a dresser with variable profile in order to provide, with dressable tools, individually different tool profile geometries.

The invention relates to a method for producing tooth flank modifications on toothing of workpieces, in which the workpiece and a tool are moved relative to one another and, as a result, material is removed from the tooth flank (3) of the workpiece. Different tooth flank modifications are generated on teeth (1) of the workpiece by means of a continuously rolling manufacturing process, by the tool comprising individually different tool profile geometries which generate the different tooth flank modifications on the teeth (1) of the workpiece. The tool can be a dresser with variable profile in order to provide, with dressable tools, individually different tool profile geometries.

A designing method of a gear skiving cutter that includes: constructing a cutter manufacturing tool with a plurality of asymmetrical tooth structures and a base material for the gear skiving cutter; simulating relative movements of the cutter manufacturing tool and the base material based on multi-axes in a relative motion coordinate system to have the cutter manufacturing tool process the surface of the base material; and forming a plurality of cut teeth on the base material by the plurality of tooth structures of the cutter manufacturing tool. An outer contour of each cut tooth is designed in advance so that gear teeth on a gear workpiece with a planned grinding allowance can be formed when the gear workpiece is processed by the gear skiving cutter. The grinding allowance on either side of each gear tooth can be kept uniform, and the grinding allowance on both sides of each gear tooth can be closely the same.

A designing method of a gear skiving cutter that includes: constructing a cutter manufacturing tool with a plurality of asymmetrical tooth structures and a base material for the gear skiving cutter; simulating relative movements of the cutter manufacturing tool and the base material based on multi-axes in a relative motion coordinate system to have the cutter manufacturing tool process the surface of the base material; and forming a plurality of cut teeth on the base material by the plurality of tooth structures of the cutter manufacturing tool. An outer contour of each cut tooth is designed in advance so that gear teeth on a gear workpiece with a planned grinding allowance can be formed when the gear workpiece is processed by the gear skiving cutter. The grinding allowance on either side of each gear tooth can be kept uniform, and the grinding allowance on both sides of each gear tooth can be closely the same.

A gear cutter tool for cutting internal gear teeth into a workpiece to form a gear is provided. The gear cutter tool is configured to rotate about a longitudinal gear cutter rotational axis. The workpiece is configured to rotate about a workpiece rotational axis. The gear cutter tool includes a gear cutter having a plurality of cutting teeth. Each cutting tooth of the plurality of cutting teeth having a tooth face that defines a cross-axis tooth angle defined between the tooth face and a line transverse to the longitudinal gear cutter rotational axis. The cross-axis tooth angle is between one and fifteen degrees. A cross-axis tool angle of the gear cutter tool defined between the longitudinal gear cutter rotational axis and the workpiece rotational axis is substantially near zero degrees.

A gear cutter tool for cutting internal gear teeth into a workpiece to form a gear is provided. The gear cutter tool is configured to rotate about a longitudinal gear cutter rotational axis. The workpiece is configured to rotate about a workpiece rotational axis. The gear cutter tool includes a gear cutter having a plurality of cutting teeth. Each cutting tooth of the plurality of cutting teeth having a tooth face that defines a cross-axis tooth angle defined between the tooth face and a line transverse to the longitudinal gear cutter rotational axis. The cross-axis tooth angle is between one and fifteen degrees. A cross-axis tool angle of the gear cutter tool defined between the longitudinal gear cutter rotational axis and the workpiece rotational axis is substantially near zero degrees.

A surface-coated cutting tool comprises a hard coating layer that includes a TiAlN layer and is provided on a surface of a cutting tool body. In case the composition of the TiAlN layer is expressed by a formula: (Ti.sub.xAl.sub.1-x)N, 0.10≤x≤0.35 (here, x is in atomic ratio) is satisfied. In the TiAlN layer, a high Ti band-like region is present in a direction at 30 degrees or less with respect to a line normal to the surface of the cutting tool body. An average composition X of the Ti component in the high Ti band-like region satisfies (x+0.01)≤X≤(x+0.05), an average width W of the high Ti band-like region is 30 to 500 nm, and an average area ratio St of the high Ti band-like region is 3 to 50 area %.

A method for providing teeth on working gears by cutting, wherein the working gear and the cutting tool are driven in rotation at a predetermined speed ratio along axes oriented at an intersection angle. The flanks of the cutting teeth form edges having flank cutting sections arranged on the edges of a gap between two adjacent teeth and extend along a first contour line, and which as a result of an advance in the direction of the working gear engage in a cutting manner to produce teeth having a flank contour predetermined by the shape of the cutting edge. Each of the flank cutting sections is adjoined by a tip cutting section which extends along a second contour line in the region of the base of the cutting tooth gap, wherein the second contour line is curved such that at least partially rounded tooth tips are produced on the teeth.

A method for providing teeth on working gears by cutting, wherein the working gear and the cutting tool are driven in rotation at a predetermined speed ratio along axes oriented at an intersection angle. The flanks of the cutting teeth form edges having flank cutting sections arranged on the edges of a gap between two adjacent teeth and extend along a first contour line, and which as a result of an advance in the direction of the working gear engage in a cutting manner to produce teeth having a flank contour predetermined by the shape of the cutting edge. Each of the flank cutting sections is adjoined by a tip cutting section which extends along a second contour line in the region of the base of the cutting tooth gap, wherein the second contour line is curved such that at least partially rounded tooth tips are produced on the teeth.