Rack-and-pinion steering gear unit

Abstract

The present invention provides a rack-and-pinion steering gear unit whereby the operating force of a steering wheel or the operating assist force of an electric motor can be prevented from increasing, and whereby response can be improved in fine operations during forward travel and the like. A back surface (29) of a rack shaft (9) is elastically pressed toward a pinion shaft (5) by a pressing roller (34). The pressing roller (34) is rotatably supported, via a radial needle bearing (16a), on a support shaft (33) supported on and fixed to a holder (30). A thrust needle bearing (35) for bearing a thrust load applied by the pressing roller (34) is provided between an inner side surface of the holder (30) and two side surfaces of the pressing roller (34) in the axial direction.

Description

technical field [0001] The present invention relates to a rack and pinion steering unit constituting a steering device for applying a steering angle to steering wheels of an automobile, and more particularly to a rack and pinion steering unit using a rolling rack guide. Background technique [0002] As a mechanism for converting rotational motion input from a steering wheel into linear motion for applying a steering angle, a rack and pinion steering unit is used. Steering devices equipped with rack and pinion steering gear units are described in Japanese Patent Application Laid-Open No. 2009-184591, Japanese Patent Laid-Open No. 2004-17872, Japanese Patent Application Laid-Open No. 61-124471, etc., and conventionally widely known. [0003] Figure 7 An example of a steering device incorporating a rack and pinion steering unit is shown. This steering device is a so-called column assist type rack and pinion power steering device. That is, in order to reduce the operating fo...

AI Technical Summary

Problems solved by technology

[0013] In this structure, since the inclined surface of the rack shaft is biased in the axial direction of the rack shaft, the rack shaft may be inclined with respect to the axis.

In addition, there may be manufacturing errors between the respective tapered surfaces of the pressing rollers divided into two, or gaps may occur between the inner peripheral surface of the pressing roller and the outer peripheral surface of the support shaft.

Therefore, in the case of this structure, due to the above-mentioned phenomenon, the meshing state of the meshing portion of the pinion teeth and the rack teeth cannot be properly maintained. sense of incongruity

If the meshing state of the meshing portion of the pinion teeth and the rack teeth deviates significantly from the proper state, damage, etc., may occur at the meshing portion due to a local collision.

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