Eccentric oscillating-type planetary gear device

Abstract

Deformation of bridge sections in an externally toothed gear and of outer teeth is suppressed, and this extends the life of tooth surfaces of external teeth (19), improves vibration characteristics, and drastically increases output torque while preventing a planetary gear device (11) from becoming large in size. To achieve the above, a ratio obtained by dividing the diameter (D) of pins constructing internal teeth (14) by the pitch (P) of the internal teeth (14) is made smaller to an extent where the tooth tops (19a) of the external teeth (19) are radially outside the inner periphery (15a) of an internally toothed gear (15), or alternatively, a meeting point (C) where the lines (S) of action of reaction forces (K) as drive force components meet is moved more radially outward than a conventional position so as to be positioned between a pin circle (P) passing the centers of all the internal teeth (pins) (14) and an outer end passing circle (G) passing radially outer ends of through-holes (22), or further alternatively, the amount (H) of eccentricity of an externally toothed gear (18) relative to an internally toothed gear is set not less than 0.5 times the radius (R) of the internal teeth (pins)(14).

Description

[0001] This case is a divisional application of a patent application with an application date of January 28, 2005, an application number of 200580003676.9, and an invention title of "eccentric oscillating planetary gear device". technical field [0002] The present invention relates to an eccentric oscillating planetary gear device, which eccentrically oscillates an external gear meshed with an internal gear through a crankshaft. Background technique [0003] As a conventional eccentric oscillating planetary gear device, for example, a device described in Patent Document 1 is known. [0004] The device is provided with: an internal gear with a plurality of cylindrical rollers arranged at a certain pitch on the inner circumference; an external gear with a plurality of crank shaft holes and through holes, and a trochoid on the outer circumference. The external teeth formed by the tooth shape mesh with the above-mentioned internal teeth and the number of teeth is only one less ...

AI Technical Summary

Problems solved by technology

Here, since the bridge portion 105 on the external gear 104 located on the radially outer side of the through hole 103 has a thinner wall thickness than other parts, the rigidity is low. The normal direction of 103 acts on the bridge 105 with low rigidity in a direction substantially perpendicular to the extending direction of the bridge 105, so that the bridge 105 and the external teeth 101 near the bridge 105 are elastic. Deformation, the outer teeth 101 contact one end of the inner teeth (roller) 102, and there is a problem that the tooth surface life of the outer teeth 101 is shortened

[0013] Moreover, in order to prevent the tooth tops of the external teeth from interfering with the inner circumference of the internal gear, divide The amount of eccentricity of the external gear with respect to the internal gear, calculated from the number of internal teeth (rollers), must be less than 0.5 times the radius of the internal teeth (rollers) (about 0.40 to 0.45 times in conventional planetary gear units) ), as a result, there is a limit to moving the convergent point outward in the radial direction as described above, and there is a problem that the output torque cannot be sufficiently increased

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