KR-20260065323-A - REAR WHEEL STEERING APPARATUS

KR20260065323AKR 20260065323 AKR20260065323 AKR 20260065323AKR-20260065323-A

Abstract

The present invention relates to a rear wheel steering device. The present invention was devised to solve the above-mentioned problems and aims to provide a rear wheel steering device capable of preventing the lubricant injected into the screw nut from leaking out. The present invention is characterized by comprising: a screw nut having a hollow portion into which a lubricant is injected, which rotates by a driving force; a lead screw shaft disposed in the hollow portion, screw-coupled with the screw nut, and translationally moving within the screw nut; a sealing portion disposed on the inner side of the screw nut and formed to protrude to contact the lead screw shaft to prevent leakage of the lubricant; and a blocking portion disposed on the inner side of the screw nut and on the side of the sealing portion to prevent the sealing portion from detaching to the outside of the screw nut.

Inventors

김희진

Assignees

현대모비스 주식회사

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (10)

A screw nut that rotates by a driving force, has a lubricant applied to its inner side, and has a hollow portion for storing the lubricant; A lead screw shaft disposed in the above-mentioned hollow portion, screw-coupled with the above-mentioned screw nut, and translationally moving within the above-mentioned screw nut; A sealing portion disposed on the inner side of the screw nut and formed to protrude to contact the lead screw shaft to prevent leakage of the lubricant; and A rear wheel steering device characterized by including a blocking member disposed on the inner side of the screw nut and disposed on the side of the sealing member, which prevents the sealing member from moving outward from the screw nut.
In paragraph 1, The above hollow part is A first hollow portion in which the above lubricant is stored; and A rear wheel steering device characterized by including a second hollow portion in which the above lubricant is stored and the above sealing portion and the above blocking portion are disposed.
In paragraph 2, A rear wheel steering device characterized in that the inner diameter of the blocking portion is smaller than the outer diameter of the sealing portion.
In paragraph 3, A rear wheel steering device characterized by further including a fixing groove in which the above-mentioned second hollow portion is fitted and coupled with the above-mentioned blocking portion.
In paragraph 4, A rear wheel steering device characterized in that the depth of the fixed groove is smaller than the thickness of the blocking portion, and the blocking portion protrudes outward from the fixed groove to restrain the detachment of the sealing portion.
In paragraph 5, A rear wheel steering device characterized in that one side of the above-mentioned fixed groove is provided with an inclined section in which the width continuously decreases.
In paragraph 2, A rear wheel steering device further comprising: an elastic member disposed on the inner side of the screw nut and elastically deformable pressing the sealing member so as to be in close contact with the lead screw shaft.
In Paragraph 7, A rear wheel steering device characterized by including a stepped portion in which the inner diameter of the second hollow portion is smaller than the outer diameter of the sealing portion and the elastic portion, and the sealing portion and the elastic portion are seated.
In paragraph 8, The sealing portion includes a threaded portion corresponding to the groove of the lead screw shaft, and A rear wheel steering device characterized by the elastic portion being positioned between the sealing portion and the stepped portion to press the sealing portion so that the threaded portion contacts the groove of the lead screw shaft.
In Paragraph 9, A rear wheel steering device characterized by the above-mentioned screw threads being provided in multiple numbers.

Description

Rear Wheel Steering Apparatus The present invention relates to a rear wheel steering device, and more specifically, to a rear wheel steering device that prevents lubricant injected into a screw nut from leaking out. Steering systems are evolving into a steer-by-wire form that is not mechanically directly connected to the steering wheel operated by the driver. As steer-by-wire technology advances, technology for Rear Wheel Steering (RWS) is also advancing. Rear Wheel Steering is included in All Wheel Steering (AWS), which can improve vehicle responsiveness and driving safety while reducing the turning radius. Generally, a vehicle's rear-wheel steering system has a structure in which a steering shaft is coupled to a screw nut. A male screw pattern is formed on the steering shaft, and a female screw pattern that meshes with the male screw pattern of the steering shaft is formed on the screw nut. When the screw nut is rotated by a drive unit, the steering shaft moves axially, and the vehicle's rear wheels are steered by the operation of the steering shaft. The steering shaft can move axially by means of a screw nut. At this time, friction may occur between the steering shaft and the screw nut, and a lubricant may be used between the steering shaft and the screw nut to reduce this friction. To increase the operating life of the steering shaft and the screw nut, a structure capable of preventing the leakage of the lubricant is required. Meanwhile, the background technology of the present invention is disclosed in Korean Published Patent Application No. 10-2018-0120447 (published Nov. 06, 2018, Title of Invention: Rear Wheel Steering Device). FIG. 1 is a perspective view of a rear wheel steering device according to one embodiment of the present invention. FIG. 2 is a perspective view of a driving unit, a driving force transmission unit, and a steering unit of a rear wheel steering device according to one embodiment of the present invention. FIG. 3 is a cross-sectional view of a screw nut of a rear wheel steering device according to one embodiment of the present invention, cut along the line III-III' of FIG. 2. FIG. 4 is an exploded perspective view of a screw nut, a sealing part, an elastic part, and a blocking part of a rear wheel steering device according to one embodiment of the present invention. FIG. 5 is a cross-sectional view of a screw nut of a rear wheel steering device according to one embodiment of the present invention. FIG. 6 is a drawing of a second hollow portion of a rear wheel steering device according to one embodiment of the present invention. FIG. 7 is a drawing of a fixing groove of a rear wheel steering device according to one embodiment of the present invention. FIG. 8 is a side view of a screw nut of a rear wheel steering device according to one embodiment of the present invention. Hereinafter, an embodiment of a rear-wheel steering device according to the present invention will be described with reference to the contents described in the attached drawings. However, the present invention is not limited or restricted by exemplary embodiments. In this process, the thickness of lines or the size of components depicted in the drawings may be exaggerated for convenience. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, the definitions of these terms should be based on the content throughout this specification. Furthermore, in this specification, when a part is described as being “connected (or joined)” to another part, this includes not only cases where they are “directly connected (or joined)” but also cases where they are “indirectly connected (or joined)” with other members interposed between them. In this specification, when a part is described as “comprising (or having) a certain component,” this means that, unless specifically stated otherwise, it does not exclude other components but may additionally “comprising (or having)” other components. The purpose and effects of the present invention may be naturally understood or become clearer through the following description, and the purpose and effects of the present invention are not limited solely to the description below. Furthermore, in describing the present invention, if it is determined that a description of known technology related to the present invention may unnecessarily obscure the essence of the invention, such detailed description will be omitted. FIG. 1 is a perspective view of a rear wheel steering device according to one embodiment of the present invention, and FIG. 2 is a perspective view of a driving unit, a driving force transmission unit, and a steering unit of a rear wheel steering device according to one embodiment of the present invention. Referring to FIGS. 1 and 2, the rear wheel steering device (1) includes a housing (10), a driving unit (20), a driving force transm