Transmission ratio variable mechanism and steering device for vehicle equipped with it

Abstract

A transmission ratio variable mechanism (5) is provided with: an input member (20) and an output member (22) capable of rotation about a first axis (A); an inner race (391) for differentially rotatably coupling to each member (20, 22); an outer race (392) for rotatably supporting the inner race (391) via a rolling element 393; and a transmission ratio variable mechanism-use electric motor (23) for rotation-driving the outer race (392). A second axis (B) which is a center line of the inner race (391) and the outer race (392) is inclined to the first axis (A). A first concave-convex engaging section (64) for engaging one side end surface (71) of the inner race (391) and a power transmission surface of the input member (20) corresponding to the one end surface (71) are arranged. There is provided a second concave-convex engaging section (67) for engaging the other end surface (73) of the inner race (391) and a power transmission surface of the output member (22).

Description

technical field [0001] The present invention relates to a transmission ratio variable mechanism capable of changing the transmission ratio of the steering angle of a steered wheel to the steering angle of a steering member, and a vehicle steering device having the same. Background technique [0002] There are known vehicle steering devices provided with a transmission ratio variable mechanism capable of changing the transmission ratio of an output rotation angle to an input rotation angle (for example, refer to Patent Documents 1 to 3). [0003] The steering device for a vehicle in Patent Document 1 is provided with a gear reducer including gears whose teeth are formed of "rollers" between an upper steering shaft connected to a steering wheel and a lower steering shaft connected to a steering gear. Both ends of the "roller" are held by a cage and can rotate relative to the gear body. [0004] The transmission ratio variable mechanism provided in the gear reducer has: a firs...

AI Technical Summary

Problems solved by technology

However, since the second and third gears with large diameters are formed at both ends of the outer ring gear portion of the swing gear, once the first and fourth gears support the larger diameter outer ring gear portion from both sides in the axial direction, The two ends of the diameter direction of the support spacing is longer

Therefore, under the action of the force in the axial direction, the deflection of the swing gear increases, resulting in the weakening of the force acting on the meshing part between the meshing gears.

[0009] In addition, in the structure of Patent Document 1, it is necessary to use a cage in addition to the "rollers" in terms of the number of gears, so the number of parts is large

Higher part counts increase the task of assembly

Images