A drive device includes: a motor; and a power transmission device that transmits power of the motor to a wheel. Further, in the power transmission device has a meshing portion in which a meshing tooth that is formed on an input-side rotation member and a meshing tooth that is formed on an output-side rotation member mesh with each other on a power transmission path between the motor and the wheel, the meshing tooth has a driving-side teeth surface that makes contact for transmission of power from the motor to the wheel and a non-driving-side teeth surface that makes contact for transmission of power from the wheel to the motor, and in the meshing tooth, a tooth root of the driving-side teeth surface has a higher breaking strength than a tooth root of the non-driving-side teeth surface.

A torque transfer device has plural planets arranged for planetary rotation about one or more sun gears and within one or more ring gears. Each planet includes at least one planetary gear set comprising plural planetary gears connected to rotate together, but having a different diameter to form a differential gear system. To improve load sharing, the plural planetary gears of each planetary gear set may have a different helical angle, the plural planetary gear sets being axially movable with respect to one another. Alternatively or in addition, the planetary gears may be made flexible with respect to radial forces.

A resin helical gear is formed by setting a first machining reference line obliquely coupling a tooth tip side of a first tooth to a tooth root side of a second tooth on another end side in the tooth width direction along a tooth surface, and a second machining reference line obliquely coupling a tooth tip side of the second tooth to a tooth root side of the first tooth along the tooth surface. Then, the tooth surface is cut out from the first machining reference line to the tooth root of the first tooth while the tooth surface is cut out from the second machining reference line to the tooth root of the second tooth. Then, an involute tooth profile form is left on a tooth tip side of the tooth with respect to the first machining reference line and the second machining reference line.

An assembly for acoustically influencing toothed wheels, including at least one first toothed wheel having teeth and one second toothed wheel having teeth, wherein the teeth have flanks, wherein at least one flank of a tooth of the first toothed wheel can be engaged with a flank of a tooth of the second toothed wheel, wherein at least one flank of a tooth of the first toothed wheel forms a contact zone or, in the ideal case, a contact line with an engaging flank of a tooth of a second toothed wheel, wherein the contact zone or the contact line is formed at an angle α.sub.Aq, in particular between 5° and 85° or between 95° and 175°, in relation to an axis of an undulation, a microangle distribution, and/or a microangle periodicity of the engaging flank of the tooth of the second toothed wheel.

The invention includes a toothing of a gearwheel having a plurality of teeth, the tooth flanks of which have a main region and a tooth root region. The tooth root region extends from a root circle (FP) as far as a main circle (d.sub.H), as considered in the end section or normal section through the axis of rotation of the gearwheel. As considered in each case in the end section or normal section, the tooth flanks in the tooth root region are designed as a Bézier curve from a relevant diameter (d.sub.r) in the direction of the tooth root. The Bézier curve merges in each case at a main point (P.sub.0, P.sub.3) in the relevant diameter (d.sub.r) in a continuous tangent into the tooth profile of the main region.

A gear drive device includes a first gear, a second gear that meshes with the first gear to allow torque transmission, and a biasing member that applies rotational torque in one direction to the first gear or the second gear. The first gear and the second gear are brought into contact at a contacting tooth surface thereof by the biasing member. At least one of the first gear and the second gear includes a non-contacting tooth surface that is on an opposite side of the contacting tooth surface and partially removed.

A three-dimensional tooth profile of internal teeth in a strain wave gearing is a basic internal-teeth tooth profile at an internal-teeth outer end, and is a reduced tooth profile, in which the basic internal-teeth tooth profile is proportionally reduced only in the lateral direction, at other tooth-trace-direction positions. A three-dimensional tooth profile of external teeth is a basic external-teeth tooth profile at an external-teeth outer end, and is an increased tooth profile, in which the basic external-teeth tooth profile is proportionally increased only in the lateral direction, at other tooth-trace-direction positions. Tooth cutting process becomes easier than when only the external teeth employ a three-dimensional tooth profile. Since the tooth profiles, which are proportionally reduced and increased only in the lateral direction along the tooth trace direction, are employed, it is further easier in tooth cutting process.

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 drive device includes: a motor; and a power transmission device that transmits power of the motor to a wheel. Further, in the power transmission device has a meshing portion in which a meshing tooth that is formed on an input-side rotation member and a meshing tooth that is formed on an output-side rotation member mesh with each other on a power transmission path between the motor and the wheel, the meshing tooth has a driving-side teeth surface that makes contact for transmission of power from the motor to the wheel and a non-driving-side teeth surface that makes contact for transmission of power from the wheel to the motor, and in the meshing tooth, a tooth root of the driving-side teeth surface has a higher breaking strength than a tooth root of the non-driving-side teeth surface.

The method for manufacturing the worm wheel includes a step of combining the first molds for molding the first tooth surfaces of the wheel teeth to be pushed by the shaft tooth when the worm shaft rotates in the direction and the second molds for molding the second tooth surfaces of the wheel teeth to be pushed by the shaft tooth when the worm shaft rotates in the direction to form the cavities defined by the first molds and the second molds, a step of injecting the molten resin into the cavities to mold the wheel teeth, and a step of separating the first molds and the second molds from each other in the direction oblique to the tooth traces of the wheel teeth.