An adjustment device configured to move first bevel gear and second bevel gear that are disposed on base and are meshed with each other. Adjustment device includes first adjustment assembly, and second adjustment assembly. First adjustment assembly includes first fluid-driven power source, first brake component and first displacement sensor. First fluid-driven power source includes first cylinder housing and first piston. First cylinder housing is configured to be disposed on base. First piston is movably disposed on first cylinder housing. First bevel gear is configured to be disposed on first piston. First piston is configured to move first bevel gear along first axial direction. First brake component is configured to be disposed on base and configured to stop or release first piston. First displacement sensor is disposed on first cylinder housing and configured to generate displacement data related to first piston.

A tooth shape of the first tooth-shaped die part is formed have a constant tooth width from an upper end to a lower end and to correspond to a tooth width of a part in which a desired crowning has been produced. A tooth shape of the second tooth-shaped die part is formed to have a constant tooth width from an upper end to a lower end and to correspond to a tooth width of a central part, which is a part other than the part in which the desired crowning has been produced. A crowning forming method includes the steps of: forming a tooth shape on an outer circumference of the material by the tooth shape of the first tooth-shaped die part; and pressing the central part of the tooth shape of the material against the tooth shape of the inner circumference of the second tooth-shaped die part.

A planetary gearbox with two rows of planets between an inner race and a coaxial outer race. An input gear may also mesh with the inner planets or the outer planets. To avoid unmeshing of the gears due to twisting from the applied torque, a camming effect may be used in which applied torque generates a radial preload. The gears that mesh with the input gear may do so at portions of the gears that also mesh with a corresponding one of the inner or outer race. The planets may be geared with axial portions with different helix angle. The inner race or outer race may be formed of two components geared with different helix angle to mesh with the different axial portions of the planets. By using these different components, assembly is eased as the components can be slid onto the planets axially.

A vehicle drive device uses a parallel shaft gear reducer (30) in which a gear is composed of helical gear, as a speed reducer part (B) that decelerates and outputs a rotation of an electric motor part (A). In the vehicle drive device, of meshing parts of the gears formed in the speed reducer part (B), two gears form a meshing part in which the amount of misalignment that occurs between the tooth surfaces of the two gears meshing with each other is different during driving and during coasting of a vehicle. A first tooth surface (S1) meshing with a mating tooth surface during driving is subjected to tooth surface modification, and a second tooth surface (S2) meshing with a mating tooth surface during coasting is subjected to tooth surface modification of an amount different from an amount of the tooth surface modification to the first tooth surface (S1).

A flexible gear coupling includes two external gears and two internal gears meshing with the respective two external gears. A tooth root crowning radius of each external gear is smaller than a tooth tip crowning radius of the external gear. The external gear is formed such that a reference tooth height that is a tooth height at a tooth width direction middle position is smaller than an end tooth height that is a tooth height at a tooth width direction end position. A ratio of the end tooth height to the reference tooth height is set to 1.21 or more, and/or a ratio Rc/Rb of the tooth root crowning radius to the tooth tip crowning radius is set to 0.37 or less.

A bearing including a bearing ring having an annular base and a plurality of gear teeth integrally formed with the annular base. Each gear tooth of the plurality of gear teeth includes a first flank surface extending substantially radially from the annular base, a top land surface extending substantially in the axial direction, and a chamfered surface between the top land surface and first flank surface. The chamfered surface includes a first arc with a first radius in a range of 0.1 to 0.15 times the gear module of the bearing ring. The first arc has a point of tangency with the first flank surface. The chamfered surface has length P extending in the radial direction between the point of tangency and the top land surface, and P is in the range of 0.1 to 0.15 times the gear module of the bearing ring.

An adjustment device configured to move first bevel gear and second bevel gear that are disposed on base and are meshed with each other. Adjustment device includes first adjustment assembly, and second adjustment assembly. First adjustment assembly includes first fluid-driven power source, first brake component and first displacement sensor. First fluid-driven power source includes first cylinder housing and first piston. First cylinder housing is configured to be disposed on base. First piston is movably disposed on first cylinder housing. First bevel gear is configured to be disposed on first piston. First piston is configured to move first bevel gear along first axial direction. First brake component is configured to be disposed on base and configured to stop or release first piston. First displacement sensor is disposed on first cylinder housing and configured to generate displacement data related to first piston.

A reduction gear W1 that is configured to reduce a rotation speed input to an input shaft 1, and output the reduced rotation speed from an output shaft, the reduction gear including: an inner trochoid 8 that has a wavy curved surface formed on an inner circumferential side surface thereof; an inner trochoid holder 9 that is designed to hold the inner trochoid 8; an outer trochoid 3 that has a wavy curved surface formed on an outer circumferential side surface thereof; a rotation restriction unit that is designed to restrict rotation of the outer trochoid 3 around an axis thereof; and an output pin 9 that is pinched between the outer circumferential side surface of the outer trochoid 3 and the inner circumferential side surface of the inner trochoid 8.

A gear tooth for a gear of a planetary gear device may include a profile modification that alters a profile of the gear tooth to reduce wear and noise. Aspects of the profile modification may include a planar surface that connects a tip surface of the gear tooth with a first or second side of the gear tooth. Other aspects of the profile modification may include a curved surface connecting a tip surface of the gear tooth with a first or second side of the gear tooth. The gear tooth may also include non-constant profile width as measured between the first side and the second side in a gear thickness direction extending between the top and bottom surfaces of the gear. Aspects of gear teeth with either or both the profile modification and non-constant profile width may reduce tooth wear and gear noise during operation of the planetary gear device.

The invention relates mainly to an assembly comprising: a combustion engine ring gear having a plurality of teeth, the said ring gear being defined by a modulus and a pressure angle, a starter comprising a pinion (31) able to engage with the said ring gear of the said combustion engine, the said pinion (31) having a plurality of teeth (42) is defined by a modulus (Mp) and a pressure angle (alpha_p), characterized in that a pinion product which is the product of the modulus (Mp) of the said pinion (31) and the cosine of the pressure angle (alpha_p) of the said pinion (31) is greater than a ring-gear product equal to the product of the modulus of the said ring gear and the cosine of the pressure angle of the said ring gear.