Eccentric swing type planetary gear device

Abstract

The invention provides eccentric swing type planetary gear device, 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

technical field [0001] 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 [0002] As a conventional eccentric oscillating planetary gear device, for example, a device described in Patent Document 1 is known. [0003] 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 than the internal teeth; the crankshaft is inserted into each crankshaft hole, and the external gear is eccentrically oscillated by rotation; the support body can rotatably support the above-mentioned The crankshaft also has a plu...

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

[0012] Furthermore, in order to prevent the tooth tops of the external teeth from interfering with the inner circumference of the internal gear, the externally toothed gear is obtained by dividing the position of the above-mentioned converging point (distance in the radial direction from the center of the internal gear) by the number of internal teeth (rollers). The amount of eccentricity relative to the internal gear must be less than 0.5 times the radius of the internal tooth (roller) (about 0.40 to 0.45 times in conventional planetary gear units). Outward movement is limited, and there is a problem that the output torque cannot be increased sufficiently

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