Displacement detection apparatus for linear motion mechanism and rear wheel steering apparatus for vehicle including the same

Abstract

A displacement detection apparatus (5) for a linear motion mechanism (3c) includes a nut member (36), a rod (2) including elongate grooves (2r, 2s) elongating in an axial direction of the rod (2) and a through hole (2h), a permanent magnet (5b) disposed parallel to the rod (2), a magnet block (50) made of synthetic resin and including a retaining portion (52) holding the permanent magnet (5b), a pair of leg portions (53) extending from ends of the retaining portion (52) that are spaced apart, and a nut (54) made of metal insert-molded at an intermediate position between the pair of leg portions (53), and a displacement sensor (5a) disposed opposing to the permanent magnet (5b). The pair of leg portions (53) and the nut (54) of the magnet block (50) are disposed in the elongate groove (2r) of the rod (2) and the magnet block (50) is fixed to the rod (2) by a bolt (51) screwed to the nut (54), the bolt (51) penetrating through the through hole (2h) extending through the rod (2).

Description

technical field [0001] The present invention relates to a displacement detection device installed on a linear motion mechanism for converting a rotational motion of a nut member into a linear motion of a rod to detect axial displacement of the rod. In addition, it relates to a vehicle rear wheel steering device which has the displacement detection device, is mounted on a suspension mechanism for supporting a rear wheel of a vehicle, and is used for steering the rear wheel. Background technique [0002] As a general linear motion mechanism, there is known a linear motion mechanism that has a nut member and a rod screwed with the nut member, converts the rotational motion of the nut member into the linear motion of the rod, and is also known for Displacement detection means for detecting the axial displacement of the rod portion. For example, as a rear wheel steering device constituting a part of a four-wheel steering system (4WS) of a vehicle, various types of devices are kn...

AI Technical Summary

Problems solved by technology

Therefore, in Patent Document 2, the servo unit and the electronic control unit equipped with the rear wheel steering sensor are independently formed. Although the technical inspiration for realizing integration is given, it is not conceivable to arrange the rear wheel steering sensor in the electronic control unit. Inside

[0006] On the other hand, in the wheel steering device described in Patent Document 1, the housing of the motor and the housing of the speed reduction mechanism are screwed together, and the housing of the latter and the cover are tightly connected by lock nuts. Since the displacement detection device is installed on the base, not only the number of parts is large, but also it is difficult to assemble, which is the main cause of cost increase

In addition, in Patent Document 2, the rear wheel steering angle sensor is integrated with the servo unit, but it is installed separately from the above-mentioned housing, so the number of parts is large, and it is difficult to reduce the cost.

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