The present embodiments relate to a steer-by-wire-type steering apparatus. The present embodiments may provide a steer-by-wire-type steering apparatus including: a locking member coupled to a shaft of a reaction motor and having locking teeth formed on an outer circumferential surface thereof; a pair of rotation-preventing members pivotally coupled by hinge axes at one ends thereof and having locking protrusions, which are supported by the locking teeth, formed at the opposite ends thereof; a cam rotatably coupled to a shaft of a driving motor so as to pivot the rotation-preventing members and having one side provided with one of a fixing recess and a fixing member inserted into the fixing recess; and a cam holder having one side, which faces the one side of the cam, provided with the other of the fixing recess and the fixing member.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2018-0032070, filed on Mar. 20, 2018, 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 embodiments relate to a steer-by-wire-type steering apparatus, and more particularly, to a steer-by-wire-type steering apparatus capable of preventing rotation of a steering shaft if a driver applies a steering torque on the steering shaft in excess of a reaction torque of a reaction motor.

2. Description of the Prior Art

In general, power steering has been developed and applied as a steering apparatus of a vehicle in order to assist a driver in operating a steering wheel, thereby facilitating the driving operation. Hydraulic-type power steering using hydraulic pressure, electro-hydraulic-type power steering using both hydraulic pressure and the electric power of a motor, and electric-type power steering using only the electric power of a motor have been developed and applied.

In recent years, a steer-by-wire (SBW)-type steering apparatus, which enables steering of a vehicle using an electric device, such as a motor, while removing mechanical coupling devices, such as a steering column, a universal joint, or a pinion shaft between a steering wheel and wheels, has been developed and applied.

However, since the steer-by-wire-type steering apparatus has no mechanical connections between the steering shaft and the wheels, the steering wheel may be capable of being rotated endlessly by the driver, thereby deteriorating the steering sensation of the driver.

That is, if the turning of the wheel reaches a maximum point (when the steering wheel or the wheel is in the fully turned state in the general steering apparatus), or if the wheel can no longer turn because the wheel comes into contact with the curb, it is necessary to provide related information to the driver by preventing further rotation of the steering shaft.

SUMMARY OF THE INVENTION

Therefore, the present embodiments have been made in the background described above and provide a steer-by-wire-type steering apparatus capable of preventing rotation of a steering shaft if the driver generates steering torque on the steering shaft in excess of a reaction torque of a reaction motor.

Further, the present disclosure is not limited to the above aspect, and other unmentioned aspects of the present disclosure may be clearly appreciated by those skilled in the art from the following descriptions.

The present embodiments may provide a steer-by-wire-type steering apparatus including: a locking member or lock coupled to a shaft of a reaction motor and having locking teeth formed on an outer circumferential surface thereof; a pair of rotation-preventing members or levers pivotably coupled by hinge axes at one ends thereof and having locking protrusions, which are supported by the locking teeth, formed at the opposite ends thereof; a cam rotatably coupled to a shaft of a driving motor so as to pivot the rotation-preventing members or levers and having one side provided with one of a fixing recess and a fixing member or extension inserted into the fixing recess; and a cam holder having one side, which faces the one side of the cam, provided with the other of the fixing recess and the fixing member or extension.

According to the embodiments described above, the steer-by-wire-type steering apparatus has the effect of preventing rotation of a steering shaft if the driver applies a steering torque in excess of a reaction torque of a reaction motor on the steering shaft.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the present disclosure 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 component from other components, and the property, order, sequence and the like of the corresponding component are not limited by the corresponding term. It should be noted that when 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 view illustrating the configuration of a steer-by-wire-type steering apparatus according to the present embodiments.FIG. 2is a perspective view illustrating a part of a steer-by-wire-type steering apparatus according to the present embodiments.FIG. 3is a front view illustrating a part of a steer-by-wire-type steering apparatus according to the present embodiments.FIG. 4is an exploded perspective view illustrating a part of a steer-by-wire-type steering apparatus according to the present embodiments.FIG. 5is a sectional view illustrating a part of a steer-by-wire-type steering apparatus according to the present embodiments.FIGS. 6 to 10are front views illustrating a part of a steer-by-wire-type steering apparatus according to the present embodiments.

As shown in the above drawings, the steer-by-wire-type steering apparatus according to the present embodiments includes a locking member or lock140coupled to a shaft120aof a reaction motor120and having locking teeth140aformed on the outer circumferential surface thereof, a pair of rotation-preventing members or levers141aand141bpivotably coupled to a housing127by hinge axes149at one ends thereof and having locking protrusions141cformed to be supported by the locking teeth140aat the opposite ends thereof so as to be supported by the locking teeth140aat one side and the other side of the locking member or lock140, respectively, a cam143mounted between the rotation-preventing members or levers141aand141b, rotatably coupled to a shaft125aof a driving motor125so as to pivot the rotation-preventing members or levers141aand141babout the hinge axes149, and having one side provided with one of a fixing recesses155a,155b, or155cand a fixing member or extension151inserted into the fixing recess155a,155b, or155c, and a cam holder153having one side, which faces the one side of the cam143, provided with the other of the fixing recess155a,155b, or155cand the fixing member or extension151.

The steer-by-wire-type steering apparatus according to the present embodiments include an angle sensor105and a torque sensor107, which are coupled to one side of a steering shaft103connected to a steering wheel101, and the angle sensor105and the torque sensor107detect the operation of the steering wheel101by the driver and transmit electric signals to an electronic control unit110, thereby operating the reaction motor120and a pinion shaft motor130.

The electronic control unit110controls the reaction motor120, the driving motor125, and the pinion shaft motor130based on electric signals transmitted from the angle sensor105and the torque sensor107and based on electric signals transmitted from various sensors mounted to the vehicle.

The pinion shaft motor130slides a rack bar111, which is connected to the pinion shaft113, thereby performing steering of wheels119by means of a tie rod115and a knuckle arm117, and the reaction motor120generates steering-reaction force in the opposite direction when the driver operates the steering wheel101or performs operation of the steering shaft103while the vehicle is running autonomously.

Although the drawings of the present embodiments illustrate the steering shaft103having the angle sensor105and the torque sensor107for the convenience of explanation, motor position sensors, a variety of radar, camera image sensors, and the like for transmitting steering information to the electronic control unit110may be provided, a detailed description of which will be omitted below.

Since the steering shaft103and the pinion shaft113are not mechanically connected to each other in the steer-by-wire-type steering apparatus described above, the steering wheel101may be rotated endlessly by the operation of the driver. Thus, mechanical limitation is required in order to stop the rotation of the steering shaft103at a certain angle.

That is, if the turning of the wheel119reaches a maximum point (when the steering wheel101or the wheel119is in the fully turned state in the general steering apparatus), or if the wheel119can no longer turn because the wheel comes into contact with the curb, the reaction motor120outputs the maximum reaction torque. Therefore, it is possible to prevent the steering shaft103from being rotated further in order to provide such information to the driver.

In order to prevent the rotation of the steering shaft103, the driving motor125is provided such that it is mechanically connected to the steering shaft103so that if a steering torque equal to or greater than the maximum reaction torque of the reaction motor120is generated, the rotation-preventing members or levers141aand141bare operated so as to stop the rotation of the steering shaft103.

A steering column123fixed to the chassis of a vehicle is provided with the steering shaft103coupled to the steering wheel101. In addition, the reaction motor120, providing steering-reaction force to the steering shaft103, and the driving motor125operating to stop the rotation of the steering shaft103if a steering torque equal to or greater than the maximum reaction torque of the reaction motor120is generated on the steering shaft103, are provided at both sides of a housing127at one side of the steering column123.

A first pulley131is coupled to the steering shaft103and a second pulley135is coupled to the shaft120aof the reaction motor120. The first pulley131and the second pulley135are connected by means of a belt133.

Therefore, if the driver operates the steering wheel101, the electronic control unit110operates the reaction motor120based on signal values detected by the torque sensor107and the angle sensor105, thereby generating reaction torque in the direction opposite the rotational direction of the steering shaft103.

In addition, the locking member or lock140having the locking teeth140aformed continuously on the outer circumferential surface thereof is coupled to the shaft120aof the reaction motor120so as to be rotated along with the shaft120aof the reaction motor120. A pair of rotation-preventing members or levers141aand141bfor restricting the rotation of the locking member or lock140is provided.

One end of each of the rotation-preventing members or levers141aand141bis fixed to the housing127, which accommodates the first pulley131and the second pulley135therein, by means of the hinge axis149so as to pivot, and the opposite ends of the rotation-preventing members141aand141bhave the locking protrusions141cthat are supported by the locking teeth140aof the locking member or lock140.

In addition, the opposite ends of the rotation-preventing members or levers141aand141bare provided so as to be supported by the locking teeth140aon one side and the other side of the locking member or lock140, respectively.

As shown inFIG. 10, a rolling member or tip146resting on the locking teeth140amay be rotatably coupled to the end of the locking protrusion141c. When the locking member or lock140and the rotation-preventing members or levers141aand141bare in the connected state while rotating with respect to each other, the rolling member or tip146is able to prevent the locking member or lock140and the rotation-preventing members or levers141aand141bfrom being damaged or deformed by colliding with each other and is able to reduce noise therefrom.

A ball, a roller, or the like may be used as the rolling member or tip146, and a ball or a roller may be rotatably coupled to the end of the locking protrusion141cby a hinge-coupling method or the like.

In addition, the cam143for pivoting the rotation-preventing members or levers141aand141babout the respective hinge axes149is mounted between one ends of the rotation-preventing members or levers141aand141b, and the cam143is coupled to the shaft125aof the driving motor125so as to be rotated.

In addition, resilient members or braces145for resiliently supporting the rotation-preventing members or levers141aand141btoward the locking member or lock140are coupled to the inner surface of the housing127so that the rotation-preventing members or levers141aand141bare biased inwards based on the hinge axes149unless the cam143opens the rotation-preventing members or levers141aand141boutwards.

A support recess147is formed in the inner surface of the housing127such that the resilient member145is inserted into and supported by the support recess147. The support recess147may be formed in a protruding end portion148protruding from the inner surface of the housing127.

The cam143has a predetermined thickness and has a first portion143aand a second portion143bformed parallel to each other such that the first portion143ais longer than the second portion143bto thus form a trapezoidal shape. The rotation-preventing members or levers141aand141bpivot about the hinge axes149so as to be opened outwards or closed inwards according to the rotational position of the cam143, so that the locking protrusions141care moved to engage with or disengage from the locking teeth140a.

The cam143is mounted between the pair of rotation-preventing members or levers141aand141bwhile the shaft125aof the driving motor125is connected to a mounting hole125bthereof and rotates the rotation-preventing members or levers141aand141babout the hinge axes149so as to engage with or disengage from the locking member or lock140.

In addition, one of the fixing recess155a,155b, or155cand the fixing member or extension151inserted into the fixing recess155a,155b, or155cis formed on one side of the cam143, and the other of the fixing recess155a,155b, or155cand the fixing member or extension151is provided on one side of the cam holder153mounted parallel to the cam143and spaced apart therefrom a predetermined distance.

Hereinafter, a description will be made of an example in which the fixing member or extension151is provided on one side of the cam143and the fixing recesses155a,155b, and155cinto which the fixing member or extension151is inserted are formed on one side of the cam holder153facing the one side of the cam143, for the convenience of explanation, as shown in the drawings of the present embodiments.

In addition, a support member or compressible brace152for resiliently supporting the fixing member or extension151so as to be inserted into or removed from the fixing recesses155a,155b, and155cwhen the cam143rotates may be further provided, and the support member or compressible brace152is received in a coupling hole151aformed in the cam143having the fixing member or extension151so as to resiliently support the fixing member or extension151toward the fixing recesses155a,155b, and155c.

On the other hand, in the case where the fixing member or extension151is provided in the cam holder153, the fixing member or extension151may be resiliently supported by forming the coupling hole in the cam holder153.

The cam holder153may have a fixing hole157formed in the center thereof such that the shaft125aof the driving motor passes through the fixing hole157. The cam holder153may be fixed to a fixing portion of the housing127, or may be integrally formed on the inner surface of the housing127.

The fixing recesses155aand155cmay be formed at both ends of a circular arc, respectively, conforming to the operation angle of the cam143. Alternatively, the fixing recesses155aand155cmay be formed at both ends of a circular arc, and at least one fixing recess155bmay be further provided on the circular arc between the both ends. The present embodiments will be described with reference to an example in which three fixing recesses are provided at both ends of the circular arc and between the both ends, respectively.

In addition, a guide groove156is formed between the fixing recesses155a,155b, and155cin the circumferential direction based on the shaft125aof the driving motor125, which is the rotation center of the cam143, so that the fixing member or extension151is guided along the rotational direction without escaping from the guide groove156when the cam143rotates.

First, basic operation of the cam143will be described. As shown inFIG. 6, if both ends of the first portion143aof the cam143are positioned at one ends of the rotation-preventing members or levers141aand141b, respectively, the rotation-preventing members or levers141aand141bare opened outwards based on the hinge axes149, so that the resilient member145is compressed and the locking protrusions141care moved to disengage from the locking teeth140a.

On the other hand, as shown inFIG. 7, if the second portion143bof the cam143is positioned at the one ends of the rotation-preventing members or levers141aand141b, the rotation-preventing members or levers141aand141bare closed inwards based on the hinge axes149so that the resilient member145is restored and the locking protrusions141care moved to be inserted into the locking teeth140a.

That is, if the two ends of the first portion143aof the cam143are supported by the rotation-preventing members or levers141aand141b, the resilient members or braces145are compressed and the locking protrusions141care moved to disengage from the locking teeth140a, and if the two ends of the first portion143aof the cam143are not supported by the rotation-preventing members or levers141aand141b, the resilient members or braces145are restored and the locking protrusions141care moved to be inserted into the locking teeth140a.

In addition, if the locking protrusions141cengage with the locking teeth140a, the steering shaft103is prevented from rotating, and if the locking protrusions141cdisengage from the locking teeth140a, the steering shaft103can rotate.

In addition, rotation-support recesses142and144into which respective ends of the first portion143aof the cam143are inserted are formed in the inner surfaces of one ends of the rotation-preventing members or levers141aand141bso that the rotation of the cam143is stopped at a specific position.

The rotation-support recesses142and144include first rotation-support recesses142formed in one ends of the rotation-preventing members or levers141aand141band second rotation-support recesses144formed adjacent to the first rotation-support recesses142toward the opposite ends of the rotation-preventing members or levers141aand141b.

Therefore, if both ends of the first portion143aof the cam143are inserted into the first rotation-support recess142, the rotation-preventing members or levers141aand141bare opened outwards based on the hinge axes149, so that the resilient members or braces145are compressed and the locking protrusions141cdisengage from the locking teeth140a.

That is, if both ends of the first portion143aof the cam143are inserted into and supported by the first rotation-support recesses142, the fixing member or extension151is inserted into the fixing recess155aprovided at one end of the circular arc on the cam holder153and the locking protrusions141cdisengage from the locking teeth140a.

In addition, if one end of the first portion143aof the cam143is inserted into and supported by the second rotation-support recess144of one of the pair of rotation-preventing members or levers141aand141b, the fixing member or extension151is inserted into the fixing recess155bprovided between both ends of the circular arc on the cam holder153and the locking protrusion141cof the rotation preventing member141aor141bsupported by one end of the cam143is moved to disengage from the locking teeth140aof the locking member or lock140.

In addition, if the second portion143bof the cam143is positioned at one ends of the rotation-preventing members or levers141aand141b, the fixing member or extension151is inserted into the fixing recess155cprovided at the other end of the circular arc on the cam holder153and the locking protrusions141cof the pair of rotation-preventing members or levers141aand141bare moved to be inserted into the locking teeth140aof the locking member or lock140, thereby stopping the rotation of the steering shaft103.

The steer-by-wire-type steering apparatus according to the present embodiments may further include a torque sensor107for measuring a steering torque value generated by the steering shaft103and an electronic control unit110for determining a reaction torque value of the steering shaft103based on the steering torque value measured by the torque sensor107, transmitting the same to the reaction motor120, comparing the steering torque value and a predetermined maximum reaction torque value, and determining whether or not to operate the driving motor125.

If the steering torque value measured by the torque sensor107is less than a predetermined maximum reaction torque value, the electronic control unit110operates the driving motor125to rotate the cam143such that both ends of the first portion143aof the cam143are inserted into and supported by the first rotation-support recesses142of the rotation-preventing members or levers141aand141bso that the locking protrusions141care moved to disengage from the locking teeth140a.

In addition, if the steering torque value measured by the torque sensor107is greater than the predetermined maximum reaction torque value, the electronic control unit110operates the driving motor125to rotate the cam143such that the second portion143bof the cam143is positioned at one ends of the rotation-preventing members or levers141aand141bso that the locking protrusions141care moved to engage with the locking teeth140a.

That is, if a steering torque value in one direction (e.g., in the left-turn direction) is less than the maximum reaction torque value, the steering shaft103is maintained to be rotatable, and if a steering torque value in the left-turn direction is greater than the maximum reaction torque value, only the rotation of the steering shaft103in the left-turn direction is prevented, whereas the rotation of the steering shaft103in the right-turn direction, which is opposite the above direction, is allowed.

This will be described with reference toFIGS. 8 and 9.FIG. 8shows the case where the steering torque value in the right-turn direction is greater than the maximum reaction torque value, whereby the locking member or lock140becomes incapable of rotating in the right-turn direction (clockwise in the drawing) but is capable of rotating in the left-turn direction (counterclockwise in the drawing). Here, the case where the locking member or lock140is incapable of rotating in the right-turn direction means that the steering shaft103connected to the shaft120aof the reaction motor120by means of the first pulley131and the second pulley135is also incapable of rotating in the right-turn direction.

On the other hand,FIG. 9shows the case where the steering torque value in the left-turn direction is greater than the maximum reaction torque value, wherein the locking member or lock140becomes incapable of rotating in the left-turn direction (counterclockwise in the drawing) but remains capable of rotating in the right-turn direction (clockwise in the drawing). Here, the case where the locking member or lock140is incapable of rotating in the left-turn direction means that the steering shaft103connected to the shaft120aof the reaction motor120by means of the first pulley131and the second pulley135is also incapable of rotating in the left-turn direction.

That is, it is possible to perform control such that the steering shaft103is incapable of rotating only in one direction according to the direction in which the cam143is rotated by the driving motor125operated by the electronic control unit110.

As described above, the steer-by-wire-type steering apparatus according to the present embodiments has an effect of preventing the rotation of a steering shaft if the driver applies a steering torque in excess of a reaction torque of a reaction motor on the steering shaft.

Even if it was described above that all of the components of an embodiment of the present disclosure are coupled as a single unit or coupled to be operated as a single unit, the present disclosure is not necessarily limited to such an embodiment. 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.

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 disclosed in the present disclosure are intended to illustrate the scope of the technical idea of the present disclosure, and the scope of the present disclosure is not limited by the embodiment. 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.