Rack bar supporting device of steering apparatus for vehicle

The present disclosure provides a rack bar supporting device of a steering apparatus for a vehicle. The rack bar supporting device includes: a support yoke to support a rack bar; a first cam member configured to have a front surface supporting the support yoke toward the rack bar and to have a rear surface provided with a first cam surface inclined in a circumferential direction thereof; a second cam member configured to have a front surface provided with a second cam surface inclined in a circumferential direction thereof to correspond to the first cam surface, to have a rear surface to which one end of a torsion spring is supported and coupled; a yoke plug; and an elastic pin.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2017-0015501, filed on Feb. 3, 2017, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a rack bar supporting device of a steering apparatus for a vehicle. More particularly, in a rack bar supporting device of a rack-pinion type steering apparatus for a vehicle, the present disclosure relates to a rack bar supporting device of a steering apparatus for a vehicle which may prevent noise generated by an increase in the clearance due to abrasion of a support yoke or generated by the impact that is reversely input from the road surface to thereby provide a comfortable steering feeling to a driver while steering, and may shorten an assembling process and may prevent misassembly and loss of each component while each component is assembled into a vehicle.

2. Description of the Prior Art

Generally, a steering apparatus is an apparatus for changing the traveling direction of a vehicle according to the driver's will, and assists the driver in pointing the vehicle in the desired direction by discretionally changing the turning center of rotation of the front wheels of a vehicle.

However, such a conventional rack bar supporting device has problems in that it cannot support a rack bar properly because the clearance is increased due to abrasion of a support yoke and the rack bar, and that a rattling noise is generated in the support yoke and a yoke plug due to the increase in the clearance.

In addition, since components for supporting the rack bar need to be assembled one by one, there is a problem in that the assembly process is increased while the components are assembled into a vehicle, and the components are lost during misassembly or transportation of each component.

SUMMARY OF THE INVENTION

In this background, an aspect of the present disclosure is to provide a steering apparatus for a vehicle which may prevent noise generated by an increase in clearance due to abrasion of a support yoke or generated by the impact that is reversely input from the road surface, thereby providing a comfortable steering feeling to the driver while steering.

Another aspect of the present disclosure is to provide a steering apparatus for a vehicle which may shorten an assembling process and may prevent misassembly and loss of each component while each component is assembled into a vehicle.

Further, the aspects of the present embodiments are not limited thereto, and other aspects not mentioned can be clearly understood by those skilled in the art from the following description.

In accordance with an aspect of the present disclosure, there is provided a rack bar supporting device of a steering apparatus for a vehicle, including: a support yoke configured to be inserted into a cylinder of a gear box to support a rack bar; a first cam member configured to have a front surface supporting the support yoke toward the rack bar and to have a rear surface provided with a first cam surface inclined in a circumferential direction thereof; a second cam member configured to have a front surface provided with a second cam surface inclined in a circumferential direction thereof to correspond to the first cam surface, to have a rear surface to which one end of a torsion spring is supported and coupled, and to have an outer circumferential surface provided with an outer circumferential groove formed in an axial direction thereof; a yoke plug configured to have an inner front surface to which the other end of the torsion spring is supported and coupled to be coupled to the cylinder and to be provided with an insertion hole communicating with the outer circumferential groove; and an elastic pin configured to be inserted into the outer circumferential groove and the insertion hole so that the torsion spring is maintained in a compressed state.

As described above, according to embodiments of the present disclosure, it is possible to prevent noise generated by an increase in clearance due to abrasion of a support yoke or generated by the impact that is reversely input from the road surface, thereby providing a comfortable steering feeling to a driver while steering.

Further, according to embodiments of the present disclosure, it is possible to shorten an assembling process and may prevent misassembly and loss of each component while each component is assembled into a vehicle.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In adding reference numerals to elements in each drawing, the same elements will be designated by the same reference numerals, if possible, although they are shown in different drawings. Further, in the following description of the present disclosure, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In addition, terms, such as first, second, A, B, (a), (b) or the like may be used herein when describing components of the present disclosure. These terms are merely used to distinguish one structural element from other structural elements, and a property, an order, a sequence and the like of a corresponding structural element are not limited by the term. It should be noted that if it is described in the specification that one component is “connected,” “coupled” or “joined” to another component, a third component may be “connected,” “coupled,” and “joined” between the first and second components, although the first component may be directly connected, coupled or joined to the second component.

FIG. 1is a schematic configuration diagram showing a rack-pinion type steering apparatus for a vehicle according to embodiments of the present disclosure,FIGS. 2 to 5are exploded perspective views showing a part of a rack bar supporting device of a steering apparatus for a vehicle according to embodiments of the present disclosure,FIG. 6is a cross-sectional view showing a part of a rack bar supporting device of a steering apparatus for a vehicle according to embodiments of the present disclosure,FIGS. 7 to 9are perspective views showing a rack bar supporting device of a steering apparatus for a vehicle according to embodiments of the present disclosure,FIG. 10is a cross-sectional view showing a rack bar supporting device of a steering apparatus for a vehicle according to embodiments of the present disclosure,FIG. 11is a perspective view showing a rack bar supporting device of a steering apparatus for a vehicle according to embodiments of the present disclosure, andFIG. 12is an exploded perspective view showing a rack bar supporting device of a steering apparatus for a vehicle according to embodiments of the present disclosure.

As shown in these drawings, a rack-pinion type steering apparatus for a vehicle according to embodiments of the present disclosure includes a steering wheel100disposed in front of a driver's seat, a steering shaft105connected to the steering wheel100, a steering column103for allowing the steering shaft to be fixed to a vehicle body, a gear box130including a rack gear110and a pinion gear120for converting a rotational force received from the steering shaft105into a linear motion, a rack bar140having inner ball joints135at both ends thereof, and a tie rod150formed integrally with the balls of the inner ball joint135.

The tie rod150is connected to an outer ball joint155and transmits a force to a knuckle159to steer a wheel158.

In addition, a rack bar supporting device of the steering apparatus for a vehicle according to embodiments of the present disclosure includes a support yoke301configured to be inserted into a cylinder250of the gear box130to support the rack bar140; a first cam member310configured to have a front surface supporting the support yoke301toward the rack bar140and to have a rear surface provided with a first cam surface313inclined in a circumferential direction thereof; a second cam member320configured to have a front surface provided with a second cam surface317inclined in a circumferential direction thereof to correspond to the first cam surface313, to have a rear surface to which one end of a torsion spring321is supported and coupled, and to have an outer circumferential surface provided with an outer circumferential groove319formed in an axial direction thereof; a yoke plug325configured to have an inner front surface to which the other end of the torsion spring321is supported and coupled to be coupled to the cylinder250and to be provided with an insertion hole325acommunicating with the outer circumferential groove319; and an elastic pin330configured to be inserted into the outer circumferential groove319and the insertion hole325aso that the torsion spring321is maintained in a compressed state.

During operation of the steering apparatus for a vehicle, when a driver operates the steering wheel100, the steering shaft105connected to the steering wheel100is rotated, and the pinion gear120connected to the lower end of the steering shaft drives the rack bar140.

In the detailed description of the embodiments, for convenience of explanation, the direction of the rack bar140, which is the front side of the support yoke301, is designated as forward and the opposite direction is designated as rearward, unless otherwise specified.

Here, the rack bar140is engaged with the pinion gear120so as to convert a rotational motion of the steering shaft105into a rectilinear motion. On the rear surface of the rack bar140, a rack bar supporting device for supporting the rack bar140in the direction of the pinion gear120is provided so that the rack bar140and the pinion gear120are properly engaged with each other.

The rack bar supporting device in the present embodiments largely includes the support yoke301, the first cam member310, the second cam member320, the yoke plug325, and the like. The first cam member310and the second cam member320respectively provided with the first cam surface313and the second cam surface317formed of inclined surfaces corresponding to each other support the support yoke301toward the rack bar140by the torsion spring321.

The support yoke301is connected to the cylinder250of the gear box130while supporting the rear surface of the rack bar140via a yoke seat (not shown) provided on the front surface of the support yoke301. The support yoke301has an outer circumferential surface to which an elastic ring303is coupled, thereby preventing impact transmitted through the rack bar140from the road surface and a rattling noise during vibration.

Here, the elastic ring303is required to be made of a material having predetermined bending, elasticity, and rigidity and capable of absorbing vibration and noise, and is therefore made of an elastic material having the above-mentioned properties, such as Natural Rubber (NR), Nitrile Butadiene Rubber (NBR), Chloroprene Rubber (CR), Ethylene Propylene Terpolymer (EPDM), Fluoro rubber (FPM), Styrene Butadiene Rubber (SBR), Chlorosulphonated Polyethylene (CSM), urethane, silicone, and the like.

The first cam member310that is disposed on the rear side of the support yoke301and inserted into the cylinder250of the gear box130is configured such that its front surface supports the support yoke301toward the rack bar140and its rear surface is provided with the first cam surface313inclined in the circumferential direction. The second cam member320provided on a rear side of the first cam member310includes the second cam surface317provided on a front surface thereof and inclined in the circumferential direction so as to correspond to the first cam surface313of the first cam member310.

A first engagement portion322to which the one end of the torsion spring321is supported and coupled is provided on the rear surface of the second cam member320, and the outer circumferential groove319formed in the axial direction is provided on the outer circumferential surface of the second cam member320.

The yoke plug325, to which the second cam member320is mounted, is provided with a second engagement portion329which is formed on an inner front surface thereof and to which the other end of the torsion spring321is supported and coupled, and the second engagement portion329is coupled to the cylinder250of the gear box130.

In addition, the yoke plug325is provided with the insertion hole325acommunicating with the outer circumferential groove319of the second cam member320, and the elastic pin330is coupled to the outer circumferential groove319of the second cam member320and the insertion hole325aso that the torsion spring321is maintained in a compressed state.

A guide protrusion327formed in the axial direction is provided on an inner surface of the end of the yoke plug325and a guide groove312inserted into the guide protrusion327is provided on the outer circumferential surface of the first cam member310. Accordingly, when the second cam member320is rotated by the torsion spring321to move the first cam member310forward, the first cam member310is moved while being supported by the guide protrusion327. However, the present disclosure is not limited thereto. For example, the guide groove312may be formed in the yoke plug325and the guide protrusion327may be formed in the first cam member310.

The second cam member320, the torsion spring321, and the yoke plug325are integrally coupled by the elastic pin330coupled to the outer circumferential groove319of the second cam member320and the insertion hole325aof the yoke plug325, to form a first module350.

Accordingly, assembly and transportation can be performed in units of the first module350in which the torsion spring321is coupled to the second cam member320and the yoke plug325, thereby shortening the assembling process and preventing misassembly or loss of each component.

In addition, on the front surface of the first cam member310, an elastic member309for elastically supporting the support yoke301may be provided. The elastic member309may be formed in an annular shape tapered from an inner diameter portion thereof toward an outer diameter portion thereof and may be elastically deformed in the axial direction to provide an elastic force.

The elastic member309elastically supports the support yoke301while damping impact and vibration transmitted to the pinion gear and the rack bar140through the road surface. Here, the elastic member309is formed in an annular shape inclined in the axial direction from the inner diameter portion to the outer diameter portion to be elastically deformed in the axial direction that is a direction in which the support yoke301is supported. The elastic member309is made of a metal material such as steel because it is required to be made of a material having predetermined bending, elasticity, and rigidity and capable of absorbing vibration and noise.

In addition, the elastic member309may be made of engineering plastic material such as polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene Terephthalate (PBT), or the like in order to dampen impact and vibration as well as the above-mentioned metal materials.

On the front surface of the elastic member309, a supporting member307for supporting the elastic member309may be provided. Coupling holes307aand311are respectively provided at central portions of the supporting member307and the first cam member310so that a coupling member305is coupled to the coupling holes307aand311. As a result, the first cam member310, the elastic member309, and the supporting member307are integrally coupled to each other to form a second module340.

Accordingly, assembly and transportation can be performed in units of the second module340in which the elastic member309is coupled between the first cam member310and the supporting member307, thereby shortening the assembling process and preventing misassembly or loss of each component.

An insertion groove301ainto which a head portion305aof the coupling member305is inserted is provided on the rear surface of the support yoke301, so that the elastic member309can elastically support the support yoke301through the supporting member307while maintaining the assembled state of the second module340.

Meanwhile, the first cam member310may be provided with a communication hole313awhich communicates with the outer circumferential groove319of the second cam member320while passing through the front and rear surfaces thereof. The elastic pin330is coupled to the insertion hole325aof the yoke plug325, the outer circumferential groove319of the second cam member320, and the communication hole313aof the first cam member310, so that the first module350and the second module340may be combined.

That is, assembly or transportation can be performed in units of the first module350, the second module340, and the support yoke301. Alternatively, assembly or transportation can be performed in the state in which the first module350and the second module340are coupled to each other using the elastic pin330.

Here, the elastic pin330is provided with an elastic damping member330bbetween pin members330aand330cprovided on both sides in the radial direction so as to be elastically deformable in the radial direction, so that, when the damping member330bis inserted into the insertion hole325aof the yoke plug325and the communication hole313aof the first cam member310, the damping member330bis compressed and coupled in the radial direction.

Accordingly, it is possible to prevent the first module350and the second module340from being separated from each other and lost during transportation or assembly due to an elastic restoring force of the elastic pin330. Thereby, when the first module350and the second module340are assembled with the cylinder250of the gear box130in a combined state, assembly is facilitated and the process is shortened.

Such an elastic pin330may be separated after the first module350and the second module340are assembled to the gear box130and then separated, or after the support yoke301is worn to some extent.

That is, when the clearance is increased due to the abrasion of the support yoke301, the torsion spring321pushes the first cam member310toward the rack bar140to compensate for the clearance. Before the occurrence of the clearance due to durability progression, the elastic pin330may be held in a fixed state so that the torsion spring321is not loosened. Accordingly, an operator may remove the elastic pin330immediately after the assembly, or may remove the elastic pin330after the durability has progressed to some extent, to compensate for the clearance between the support yoke301and the rack bar140.

Meanwhile, the yoke plug325is screwed to the cylinder250of the gear box130and is fixed while being prevented from being unscrewed by a lock nut (not shown) outside the gear box130.

Such a rack bar supporting device constitutes the steering apparatus for a vehicle, together with the steering shaft, the pinion gear (see120inFIG. 2) connected to the steering shaft, the gear box130for accommodating the rack bar140provided with the rack gear engaged with the pinion gear, and the like.

In such present embodiments, as shown inFIGS. 11 and 12, a through-hole319amay be formed in the second cam member320and the elastic pin330may be coupled to the through-hole319a.

In this case, a rack bar supporting device of a steering apparatus for a vehicle according to embodiments of the present disclosure includes the support york301configured to be inserted into the cylinder250of the gear box130to support the rack bar140; the first cam member310configured to have a front surface supporting the support yoke301toward the rack bar140and to have a rear surface provided with the first cam surface313inclined in a circumferential direction thereof; the second cam member320configured to have a front surface provided with the second cam surface317inclined in a circumferential direction thereof to correspond to the first cam surface313, to have a rear surface to which one end of the torsion spring321is supported and coupled, and to have the through-hole319apassing through the front surface and the rear surface; the yoke plug325configured to have an inner front surface to which the other end of the torsion spring321is supported and coupled to be coupled to the cylinder250and to be provided with the insertion hole325acommunicating with the outer circumferential groove319; and the elastic pin330configured to be inserted into the through-hole319aand the insertion hole325aso that the torsion spring321is maintained in a compressed state.

Here, since the support yoke301, the first cam member310, the yoke plug325, and the like are the same as those described above, detailed description thereof will be omitted. The second cam member320is provided with the through-hole319aas shown inFIGS. 11 and 12, instead of the outer circumferential groove319shown inFIGS. 2 to 8, so that the elastic pin330may be coupled to the communication hole313aof the first cam member310in a state of being coupled to the through-hole319a, and the elastic pin330may be separated after the first module350and the second module340are assembled to the gear box130.

According to the embodiments having such a structure and shape, it is possible to prevent noise generated by an increase in the clearance due to the abrasion of the support yoke or generated by the impact that is reversely input from the road surface, thereby providing a comfortable steering feeling to a driver while steering.

In addition, it is possible to shorten the assembling process and to prevent misassembly and loss of each component while each component is assembled into a vehicle.

Although all the elements constituting embodiments of the present disclosure have been described above as being combined into a single unit or combined to be operated as a single unit, the present disclosure is not necessarily limited to such embodiments. That is, at least two elements of all structural elements may be selectively joined and operate without departing from the scope of the present disclosure.

In addition, since terms, such as “including,” “comprising,” and “having” mean that one or more corresponding components may exist unless they are specifically described to the contrary, it shall be construed that one or more other components can be included. All the terms that are technical, scientific or otherwise agree with the meanings as understood by a person skilled in the art unless defined to the contrary. Common terms as found in dictionaries should be interpreted in the context of the related technical writings not too ideally or impractically unless the present disclosure expressly defines them so.

The above embodiments have been described merely for the purpose of illustrating the technical idea of the present disclosure, and those skilled in the art will appreciate that various modifications and changes are possible without departing from the scope and spirit of the present disclosure. Therefore, the embodiments of the present disclosure are not intended to limit, but to illustrate the technical idea of the present disclosure, and the scope of the technical idea of the present disclosure is not limited by the embodiments. The scope of the present disclosure shall be construed on the basis of the accompanying claims in such a manner that all of the technical ideas included within the scope equivalent to the claims belong to the present disclosure.