VEHICLE STEERING DEVICE

Abstract

The present embodiment provides a vehicle steering device that can prevent the return tube from falling off the ball nut, deformation or damage despite constant steering during driving, enables the correct circulation of the ball to the ball nut through the return tube and prevents the lubricant from leaking out of the return tube in order to correctly transmit the steering assistance force.

Description

CROSS-REFERENCE TO A RELATED APPLICATION

[0001] This application claims priority to Korean Patent Application No. 10-2023-0088127, filed on July 7, 2023, which is hereby incorporated by reference for all purposes as if fully incorporated herein. BACKGROUND AREA

[0002] The present embodiments relate to a vehicle steering device, and more particularly, to a vehicle steering device that can prevent the return pipe from falling off the ball nut, deformation, or damage despite continuous steering during driving, enables proper circulation of the ball to the ball nut through the return pipe, and prevents leakage of the lubricant from the return pipe to properly transmit the steering assist force. DESCRIPTION OF THE STATE OF THE ART

[0003] A general vehicle steering device includes a steering system that leads from the steering wheel to two opposite wheels and an assist force mechanism that supplies steering assist force to the steering system.

[0004] A typical vehicle steering device includes a motor controlled by an electronic control device, a motor pulley fixed to the motor shaft, a ball nut connected to the rack via balls, a return pipe connected to the ball nut through which the balls circulate, a nut pulley connected to the outer peripheral surface of the ball nut, and a belt connected to the motor pulley and the nut pulley.

[0005] In the conventional vehicle steering device, the return pipe may fall off, deform or be damaged when the ball circulates between the return pipe and the ball nut due to constant steering while driving and shock from the road.

[0006] If the return pipe is not properly attached to the ball nut, the ball cannot rotate properly, which will reduce the steering assist force and power transmission efficiency, and the steering assist force will not be transmitted correctly.

[0007] In addition, the ball lubricant may leak during circulation through the return pipe, disrupting the smooth circulation of the ball and resulting in interrupted power transmission.

[0008] Therefore, there is a need for research to clarify the above questions. DEMOLITION

[0009] Against this background, the present embodiments provide a vehicle steering device that can prevent the return pipe from falling off the ball nut, deforming, or being damaged despite continuous steering during driving, that the ball can correctly circulate through the return pipe to the ball nut, and that the lubricant can leak from the return pipe to correctly transmit the steering assist force.

[0010] According to the present embodiments, a vehicle steering device may be provided comprising a ball nut having an inner circumferential screw groove arranged to face an outer circumferential screw groove of a rack, and having a first communication hole and a second communication hole penetrating an inner circumferential surface and an outer circumferential surface and arranged on a first side and a second side of the inner circumferential screw groove, and a return pipe having body parts formed of a first element and a second element that are symmetrical to each other to form a ball circulation path communicating with the first communication hole and the second communication hole in coupled inner surfaces, wherein a first end portion of the body part is coupled to the first communication hole and a second end portion of the body part is coupled to the second communication hole.to circulate a ball, wherein coupling flanges coupled to face each other are formed on respective body part outer surfaces of the first member and the second member, and wherein a coupling projection is formed on one of the coupling flanges to protrude in a facing direction, and a coupling hole into which the coupling projection is fitted is formed in another of the coupling flanges.

[0011] In the present embodiments, the coupling flanges may comprise two or more coupling flanges formed in the respective body parts of the first member and the second member.

[0012] In the present embodiments, the coupling flanges may comprise an even number of two or more coupling flanges formed in the respective body parts of the first member and the second member.

[0013] In the present embodiments, the coupling flanges may come into surface contact with each other when the body parts of the first and second elements are coupled together.

[0014] In the present embodiments, the respective body parts of the first member and the second member may have coupling surfaces that come into surface contact with each other, forming the ball circulation path.

[0015] In the present embodiments, an elastic member that is elastically compressed when the first member and the second member are connected to each other may be disposed between the coupling surfaces of the first member and the second member.

[0016] In the present embodiments, the elastic member may be formed integrally with the coupling surface of either the first or the second member.

[0017] In the present embodiments, the elastic element may be bonded or fused to the coupling surface of the first or second element by an adhesive.

[0018] In the present embodiments, the coupling projection may include an insertion support portion connected to the coupling flange and supported on an inner peripheral surface of the coupling hole, and an outer support portion extending from the insertion support portion in a longitudinal direction and a radial direction and protruding from the coupling hole to be supported on an outer surface of the coupling flange with the coupling hole.

[0019] In the present embodiments, the coupling projection may have a cutout portion that symmetrically separates the insertion support portion and the outer support portion.

[0020] In the present embodiments, a connecting web connecting the insertion support portion may be provided on the cutout portion.

[0021] According to the present embodiments, a vehicle steering device may be provided comprising a ball nut having an inner circumferential screw groove arranged to face an outer circumferential screw groove of a rack, and having a first communication hole and a second communication hole penetrating an inner circumferential surface and an outer circumferential surface and arranged on a first side and a second side of the inner circumferential screw groove, and a return pipe having body parts formed of a first element and a second element that are symmetrical to each other to form a ball circulation path communicating with the first communication hole and the second communication hole in coupled inner surfaces, wherein a first end portion of the body part is coupled to the first communication hole and a second end portion of the body part is coupled to the second communication hole.to circulate a ball, wherein coupling flanges coupled to face each other are formed on respective body part outer surfaces of the first member and the second member, wherein a coupling projection is formed on one of the coupling flanges to protrude in a facing direction, and a coupling hole into which the coupling projection is fitted is formed in another of the coupling flanges, wherein a fastening projection is formed in one of the body parts of the first member and the second member, and a fastening groove into which the fastening projection is inserted is formed in the other.

[0022] In the present embodiments, the fastening projection may be formed on an entire edge of the body part of the first member, and the fastening groove may be formed in an entire edge of the body part of the second member.

[0023] In the present embodiments, the fastening projection may be formed in a partial region of the edge of the body part of the first member, and the fastening groove may be formed in a remaining region of the edge.

[0024] In the present embodiments, the fastening projection and the fastening groove can be fitted into each other, coming into surface contact with each other.

[0025] In the present embodiments, the coupling flanges may comprise two or more coupling flanges formed in the respective body parts of the first member and the second member.

[0026] In the present embodiments, the coupling flanges may comprise an even number of two or more coupling flanges formed in the respective body parts of the first member and the second member.

[0027] In the present embodiments, the coupling flanges may come into surface contact with each other when the body parts of the first and second elements are coupled together.

[0028] In the present embodiments, the coupling projection may include an insertion support portion connected to the coupling flange and supported on an inner peripheral surface of the coupling hole, and an outer support portion extending from the insertion support portion in a longitudinal direction and a radial direction and protruding from the coupling hole to be supported on an outer surface of the coupling flange with the coupling hole.

[0029] In the present embodiments, the coupling projection may have a cutout portion that symmetrically separates the insertion support portion and the outer support portion.

[0030] According to the present embodiments, it is possible to provide a vehicle steering apparatus that can prevent the return pipe from falling off the ball nut, deformation, or damage despite continuous steering during driving, enables proper circulation of the ball to the ball nut through the return pipe, and prevents leakage of the lubricant from the return pipe to properly transmit the steering assist force. DESCRIPTION OF THE DRAWINGS

[0031] The foregoing and other objects, features and advantages of the disclosure will become more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings in which: Fig. 1 is a schematic diagram of a vehicle steering apparatus according to the present embodiments; Fig. 2 and Fig. 3 are perspective views showing a part of a vehicle steering apparatus according to the present embodiments; Fig. 4, Fig. 5 and Fig. 6 are exploded perspective views showing a part of a vehicle steering apparatus according to the present embodiments; Fig. 7 and Fig. 8 are perspective views showing a part of a vehicle steering apparatus according to the present embodiments; Fig. 9 and Fig. 10 are cross-sectional views showing a part of a vehicle steering apparatus according to the present embodiments; Fig. 11, Fig. 12 and Fig. 13 are perspective views showing a part of a vehicle steering apparatus according to the present embodiments; Fig. 14 is a front view showing a part of a vehicle steering apparatus according to the present embodiments; and Fig. 15 is a cross-sectional view taken along a line AA of the Fig. 14. DETAILED DESCRIPTION

[0032] In the following description of examples or embodiments of the disclosure, reference is made to the accompanying drawings, in which, for illustrative purposes, specific examples or embodiments that may be implemented are shown, and in which like reference numerals and characters may be used to designate the same or similar components even though they are shown in different accompanying drawings. Furthermore, in the following description of examples or embodiments of the disclosure, detailed descriptions of well-known functions and components incorporated herein are omitted when it is determined that the description may obscure the subject matter in some embodiments of the disclosure.The terms "include," "comprise," "consist of," and "consist of" used herein are generally intended to permit the addition of other components, unless the terms are used with the term "only." As used herein, singular forms are intended to include plural forms unless the context clearly indicates otherwise.

[0033] Terms such as "first," "second," "A," "B," "(A)," or "(B)" may be used herein to describe elements of the disclosure. None of these terms are used to define an importance, order, sequence, or number of elements, etc., but are merely used to distinguish the corresponding element from other elements.

[0034] When it is mentioned that a first element is “connected or coupled” to, “touches or overlaps” a second element, this should be interpreted to mean that the first element may be “directly connected or coupled” to, or “directly touches or overlaps” the second element, but also that a third element may be “interposed” between the first and second elements, or that the first and second elements may be “connected or coupled” to, “touches or overlaps” each other via a fourth element, etc. Here, the second element may be at least one of two or more elements that are “connected or coupled” to, “contacts or overlaps” each other, etc.

[0035] When time-related terms such as "after," "following," "next," "before," and the like are used to describe processes or operations of elements or configurations or sequences or steps of operations, processing, or methods of operation, these terms may be used to describe processes or operations that are not contiguous or consecutive, unless the term "direct" or "immediate" is used in connection therewith.

[0036] When specifying any dimensions, relative sizes, etc., it should also be understood that numerical values ​​for an element or characteristic, or corresponding information (e.g., grade, area, etc.), include a margin or range of error that may be caused by various factors (e.g., process factors, internal or external influences, noise, etc.), even if a relevant description is not specified. Furthermore, the term "could" includes all meanings of the term "may."

[0037] Fig. 1 is a schematic diagram of a vehicle steering apparatus according to the present embodiments. Fig. 2 and Fig. 3 are perspective views showing a part of a vehicle steering apparatus according to the present embodiments. Fig. 4, Fig. 5 and Fig. 6 are exploded perspective views showing a part of a vehicle steering apparatus according to the present embodiments. Fig. 7 and Fig. 8 are perspective views showing a part of a vehicle steering apparatus according to the present embodiments. Fig. 9 and Fig. 10 are cross-sectional views showing a part of a vehicle steering apparatus according to the present embodiments. Fig. 11, Fig. 12 and Fig. 13 are perspective views showing a part of a vehicle steering apparatus according to the present embodiments. Fig. 14 is a front view showing a part of a vehicle steering apparatus according to the present embodiments. Fig. 15 is a cross-sectional view taken along a line AA of the Fig. 14.

[0038] As shown in the drawings, a vehicle steering device according to the present embodiments includes a ball nut 125 having an inner circumferential screw groove 125a arranged to face an outer circumferential screw groove 120a of a rack 120, and having a first communication hole 127a and a second communication hole 127b penetrating an inner circumferential surface and an outer circumferential surface and arranged on a first side and a second side of the inner circumferential screw groove 125a, and a return pipe 150 having body parts 153a and 153b formed of a first member 150a and a second member 150b symmetrical to each other to form a ball circulation path 151a and 151b communicating with the first communication hole 127a and the second communication hole 127b in coupled inner surfaces.A first end portion of the body portion 153a and 153b is connected to the first connection hole 127a, and a second end portion of the body portion 153a and 153b is connected to the second connection hole 127b to circulate a ball. Coupling flanges 155a and 155b are formed on the outer surfaces of the respective body portions 153a and 153b of the first member 150a and the second member 150b, which are coupled in a facing manner. A coupling protrusion 157 is formed on one of the coupling flanges 155a and 155b to protrude in a facing direction, and a coupling hole 159, into which the coupling protrusion 157 is fitted, is formed in another of the coupling flanges.

[0039] In the vehicle steering device according to the present embodiments, a torque sensor 103 is coupled to one side of the steering shafts 102 and 106 connected to the steering wheel 101. When the driver operates the steering wheel 101, electrical signals from the torque sensor 103, the steering angle sensor 121, and the vehicle speed sensor 122 are sent to the motor 113, which detects the operation and steers the two opposing wheels 115.

[0040] In the vehicle steering device according to the present embodiments, the upper steering shaft 102 is connected to the lower steering shaft 106 via a universal joint, so that the steering is carried out via a rack and pinion mechanism 116 with a pinion 108 and a rack toothing 112.

[0041] The drive force of the motor 113 driven by the electronic control unit 111 is transmitted to the ball nut 125 via the motor 113 and the belt 150. The rack 120 connected to the ball nut 125 is axially displaced via the ball. Tie rods 119 are coupled to two opposite sides of the rack 120, and the tie rods 119 are connected to the steering knuckles 117, which are connected to the wheels 115 to steer the road wheels 115.

[0042] The electrical signal generated by the torque signal 103 is sent to the ECU 111, and the ECU 111 controls the motor 113 based on the electrical signal received from the torque sensor 103 and the electrical signals received from the steering angle sensor 121 and the vehicle speed sensor 122 mounted on the vehicle.

[0043] Although an example including a torque sensor 103, a steering angle sensor 121, and a vehicle speed sensor 122 is described for simplicity, an angle sensor, an engine position sensor, various radar or lidar sensors, or image sensors such as cameras may also be provided, which are not described in detail.

[0044] A power transmission structure is provided on the outer peripheral surface of the rack 120 and the inner peripheral surface of the ball nut 125 to axially displace the rack 120 to generate a steering assist force. The power transmission structure includes an outer circumferential screw groove 120a, which is spirally formed in the outer peripheral surface of the rack and has a semicircular or arcuate cross section, a ball (not shown) inserted therein, and an inner circumferential screw groove 125a, which is spirally formed in the inner peripheral surface of the ball nut 125 to correspond to the outer circumferential screw groove 120a and has a semicircular or arcuate cross section.

[0045] In the ball nut 125 in whose inner peripheral surface the inner circumferential screw groove 125a is formed, the first communication hole 127a and the second communication hole 127b penetrating the inner peripheral surface and the outer peripheral surface form a pair and are arranged to be spaced apart from each other along the inner circumferential screw groove 125a.

[0046] Therefore, balls rolling along the outer circumferential screw groove 120a and the inner circumferential screw groove 125a are moved from the first communication hole 127a to the second communication hole 127b and then returned to the first communication hole 127a through the ball circulation paths 151a and 151b of the return pipe 150.

[0047] The return pipe 150 is shaped substantially like the letter "U" and has a gentle curve without a straight portion from one end to the opposite end and includes a pair formed by the first element 150a and the second element 150b which are symmetrical to each other with respect to the center line.

[0048] The return pipe 150 includes body parts 153a and 153b, which form the ball orbits 151a and 151b on the inner surfaces when the first member 150a and the second member 150b are connected to each other. First end portions of the body parts 153a and 153b are coupled to the first connecting hole 127a, and second end portions thereof are coupled to the second connecting hole 127b.

[0049] In addition, a bearing groove 126 for connecting the first connecting hole 127a and the second connecting hole 127b is formed in the outer peripheral surface of the ball nut 125 to hold the return pipe 150 in its position.

[0050] The return pipe 150 may be made of a plastic material such as polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), or phenol formaldehyde (PF), or of a metal material.

[0051] Coupling flanges 155a and 155b are formed on the outer surfaces of the respective body parts 153a and 153b of the first member 150a and the second member 150b, which are coupled to each other. One of the two coupling flanges 155a and 155b has a coupling projection 157 formed therein, which projects in the facing direction, and the other has a coupling hole 159 formed therein, to which the coupling projection 157 is coupled.

[0052] In other words, when the coupling projection 157 is formed in the coupling flange 155a of the body part 153a of the first member 150a, the coupling hole 159 is formed in the coupling flange 155b of the body part 153b of the second member 150b, so that the first member 150a and the second member 150b are coupled to each other through the coupling projection 157 and the coupling hole 159.

[0053] The respective body portions 153a and 153b of the first member 150a and the second member 150b may have two or more coupling flanges 155a and 155b.

[0054] The respective body parts 153a and 153b of the first element 150a and the second element 150b may have an even number of two or more coupling flanges 155a and 155b.

[0055] When an even number of two or more coupling flanges 155a and 155b are molded, the first member 150a and the second member 150b can be molded in a single mold, reducing the manufacturing cost and process.

[0056] Since the coupling flanges 155a and 155b come into surface contact with the body parts 153a and 153b of the first member 150a and the second member 150b that are coupled to each other, it is possible to increase the waterproof performance of the first member 150a and the second member 150b and prevent the leakage of lubricant while the balls circulate.

[0057] The respective body parts 153a and 153b of the first member 150a and the second member 150b may have coupling surfaces 154a and 154b that come into surface contact with each other when forming the ball orbits 151a and 151b, and an elastic member 160 that is elastically compressed when coupling the first member 150a and the second member 150b may be coupled between the coupling surfaces 154a and 154b of the first member 150a and the second member 150b.

[0058] When the coupling projection 157 is fitted into the coupling hole 159, the elastic member 160 is elastically compressed while abutting on the coupling surfaces 154a and 154b of the first member 150a and the second member 150b, and in this state, the elastic member 160 can be further compressed and coupled when one end portion and another end portion of the return pipe 150 are coupled to the first connecting hole 127a and the second connecting hole 127b.

[0059] Accordingly, the waterproof performance of the first member 150a and the second member 150b can be increased, and leakage of the lubricant during the rotation of the balls can be prevented.

[0060] The elastic member 160 may be formed integrally with the coupling surfaces 154a and 154b of either the first member 150a or the second member 150b and may be coupled or fused to the coupling surfaces 154a and 154b of either the first member 150a or the second member 150b via an adhesive.

[0061] In this case, the elastic element 160 must be formed of a material capable of absorbing vibrations and noise while having a certain elasticity and rigidity, and may therefore be made of an elastic material such as natural rubber (NR), nitrile butadiene rubber (NBR), chloroprene rubber (CR), ethylene propylene terpolymer (EPDM), fluororubber (FPM), styrene butadiene rubber (SBR), chlorosulfonated polyethylene (CSM), urethane, or silicone.

[0062] The coupling projection 157, which is configured to be inserted into the coupling flange 155a and 155b, includes an insertion support portion 157a connected to the coupling flange 155a and 155b and supported on the inner peripheral surface of the coupling hole 159, and an outer support portion 157b extending from the insertion support portion 157a in the longitudinal direction and in the radial direction and protruding from the coupling hole 159 to be supported on the outer surface of the coupling flange 155a and 155b with the coupling hole 159.

[0063] In addition, the coupling projection 157 has a cutout portion 157c that symmetrically separates the insertion support portion 157a and the outer support portion 157b.

[0064] Accordingly, when the coupling projection 157 is inserted into the coupling hole 159, the insertion support portion 157a and the outer support portion 157b are elastically deformed to deform into the cutout portion 157c, which contributes to easy assembly.

[0065] As in Fig. 10, a connecting web 157d may be provided in the cutout portion 157c of the coupling projection 157 to connect the insertion support portion 157a.

[0066] The connecting web 157d is columnar or plate-shaped and connects the inner surfaces of the insertion support portion 157a. The presence of the connecting web 157d increases the restoring force by which the insertion support portion 157a and the outer support portion 157b are elastically deformed to approach the cutout portion 157c when the coupling projection 157 is inserted into the coupling hole 159 and then returned to the original position.

[0067] When the outer support portion 157b passes through the coupling hole 159 and is then positioned on the outer surface of the coupling flange 155a and 155b, the outer support portion 157b can be easily restored to the original shape, so that the fastening force is maintained in the correct position without falling off.

[0068] Meanwhile, the present embodiments may include a ball nut 125 having an inner circumferential screw groove 125a arranged to face an outer circumferential screw groove 120a of a rack 120, and having a first communication hole 127a and a second communication hole 127b penetrating an inner circumferential surface and an outer circumferential surface and arranged on a first side and a second side of the inner circumferential screw groove 125a, and a return pipe 150 having body parts 153a and 153b formed of a first member 150a and a second member 150b symmetrical to each other to form a ball circulation path 151a and 151b communicating with the first communication hole 127a and the second communication hole 127b in coupled inner surfaces.A first end portion of the body portion 153a and 153b is connected to the first connection hole 127a, and a second end portion of the body portion 153a and 153b is connected to the second connection hole 127b to circulate a ball. Coupling flanges 155a and 155b are formed on the outer surfaces of the respective body portions 153a and 153b of the first member 150a and the second member 150b, which are coupled in a facing manner. A coupling protrusion 157 is formed on one of the coupling flanges 155a and 155b to protrude in a facing direction, and a coupling hole 159, into which the coupling protrusion 157 is fitted, is formed in another of the coupling flanges. A fastening projection 161 is provided in one of the body parts 153a and 153b of the first member 150a and the second member 150b, and a fastening groove 163 into which the fastening projection 161 is inserted is provided in the other.

[0069] The ball nut 125 is the same as described above and will not be explained in more detail below. The following description focuses primarily on the Fig. 11 to 15, which differ from the configurations described above.

[0070] Referring to the Fig. 11 to 15 together with the Fig. 2 to 10, the fixing projection 161 is provided in one of the body parts 153a and 153b of the first member 150a and the second member 150b, and the fixing groove 163 into which the fixing projection 161 is inserted is provided in the other.

[0071] The fastening projection 161 may be provided in the entire edge of the body part 153a of the first element 150a, as shown in Fig. 11, and the fastening groove 163 may be provided in the entire edge of the body part 153b of the second element 150b, as shown in Fig. 12 shown.

[0072] Since the coupling projection 157 of the coupling flange 155a and 155b is fitted into the coupling hole 159 when the first member 150a and the second member 150b are coupled, the fastening projection 161 and the fastening groove 163 of the body part 153a and 153b are also coupled.

[0073] As in Fig. 13, the fastening projection 161 may be provided in a partial area of ​​the edge of the body part 153a of the first element 150a, and the fastening groove 163 may be provided in the remaining area of ​​the edge.

[0074] In this case, since the first element 150a and the second element 150b have the same shape and can be manufactured with a single mold, the manufacturing cost and the process can be reduced.

[0075] The fastening protrusion 161 and the fastening groove 163 are coupled to each other and come into surface contact with each other. Accordingly, the watertightness of the first member 150a and the second member 150b can be increased and lubricant leakage during the rotation of the balls can be prevented.

[0076] The respective body portions 153a and 153b of the first member 150a and the second member 150b may have two or more coupling flanges 155a and 155b.

[0077] Furthermore, an even number of two or more coupling flanges 155a and 155b may be formed in the respective body parts 153a and 153b of the first member 150a and the second member 150b. When an even number of two or more coupling flanges 155a and 155b are formed in this way, the first member 150a and the second member 150b can be molded with a single mold, reducing manufacturing costs and process time.

[0078] Since the coupling flanges 155a and 155b are coupled to each other while coming into surface contact with the body parts 153a and 153b of the first member 150a and the second member 150b that are coupled to each other, it is possible to increase the waterproof performance of the first member 150a and the second member 150b and prevent the leakage of lubricant while the balls circulate.

[0079] The coupling projection 157 includes an insertion support portion 157a connected to the coupling flange 155a and 155b and supported on the inner peripheral surface of the coupling hole 159, and an outer support portion 157b extending from the insertion support portion 157a in the longitudinal direction and radial direction and protruding from the coupling hole 159 to support on the outer surface of the coupling flange 155a and 155b with the coupling hole 159.

[0080] The coupling protrusion 157 has a cutout portion 157c that symmetrically separates the insertion support portion 157a and the outer support portion 157b. Therefore, when the coupling protrusion 157 is inserted into the coupling hole 159, the insertion support portion 157a and the outer support portion 157b are elastically deformed to approach the cutout portion 157c, facilitating assembly.

[0081] Meanwhile, support projections 152a and 152b are provided at two opposite end portions of the return pipe 150. The support projections 152a and 152b protrude from the outer peripheral surface and come into close contact with each other when fitted into the first connection hole 127a and the second connection hole 127b.

[0082] The support projections 152a and 152b protrude radially from the outer peripheral surface of the body parts 153a and 153b of the return pipe 150, and when assembling the return pipe 150, the support projections 152a and 152b are elastically deformed and fitted into the first connecting hole 127a and the second connecting hole 127b, so that the connection does not fall off despite vibration and external impact due to the circulation of the balls.

[0083] The support projections 152a and 152b are formed on the first element 150a at one end portion of the return pipe 150 and on the second element 150b at the other end portion of the return pipe 150.

[0084] In other words, since the support projections 152a and 152b are formed in a semicircular shape at one end portion and the other end portion of the return pipe 150, respectively, it is possible to maintain the strength of the fastening while preventing foreign matter or powder from entering the ball nut 125 when the support projections 152a and 152b are broken during assembly.

[0085] A bearing 140, which is coupled to a gear housing (not shown) to support the rotation of the ball nut 125, is coupled to one outer peripheral end portion of the ball nut 125, and a nut pulley 130 is coupled to the other outer peripheral end portion of the ball nut 125. The inner peripheral surface of the nut pulley 130 is spaced from the outer peripheral surface of the ball nut 125 to form a clearance.

[0086] The nut pulley 130 coupled to the ball nut 125 is arranged parallel to the motor pulley 123 connected to the shaft of the motor 113, and the belt 150 is mounted on the motor pulley 123 and the nut pulley 130 to transmit the rotational force from the motor 113 to the rack 120 via the ball nut 125, and the rack 120 is moved left and right by the operation of the ball nut 125 to thereby generate a steering assist force.

[0087] According to the present embodiments, it is possible to provide a vehicle steering apparatus that can prevent the return pipe from falling off the ball nut, deformation, or damage despite continuous steering during driving, enables proper circulation of the ball to the ball nut through the return pipe, and prevents leakage of the lubricant from the return pipe to properly transmit the steering assist force.

[0088] The above description is presented to enable those skilled in the art to implement and utilize the technical idea of ​​the disclosure and has been provided in the context of a specific application and its requirements. Various modifications, additions, and substitutions to the described embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the disclosure. The above description and the accompanying drawings exemplify the technical idea of ​​the disclosure for purely illustrative purposes. That is, the disclosed embodiments are intended to illustrate the scope of the technical idea of ​​the disclosure.Thus, the scope of the disclosure is not limited to the embodiments shown, but should be considered to be broadest in scope consistent with the claims. The scope of the disclosure should be interpreted based on the following claims, and all technical ideas within the scope of their equivalents should be considered included within the scope of the disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] KR 10-2023-0088127

[0001]

Claims

[1] Vehicle steering device comprising: a ball nut (125) having an inner circumferential screw groove (125a) arranged to face an outer circumferential screw groove (120a) of a rack (120), and having a first communication hole (127a) and a second communication hole (127b) penetrating an inner circumferential surface and an outer circumferential surface and arranged on a first side and a second side of the inner circumferential screw groove (125a); and a return pipe (150) having body parts (153a, 153b) formed of a first element (150a) and a second element (150b) which are symmetrical to each other to form a ball circulation path (151a, 151b) communicating with the first communication hole (127a) and the second communication hole (127b) with coupled inner surfaces, wherein a first end portion of the body part (153a, 153b) is coupled to the first communication hole (127a) and a second end portion of the body part (153a, 153b) is coupled to the second communication hole (127b) to circulate a ball, wherein coupling flanges (155a, 155b) which are coupled to face each other are provided on the respective outer surfaces of the body part (153a, 153b) of the first element (150a) and the second element (150b), and wherein a coupling projection (157) is formed on one of the coupling flanges (155a, 155b) to protrude in a facing direction,and a coupling hole (159) into which the coupling projection (157) is fitted is formed in another of the coupling flanges (155a, 155b). [2] A vehicle steering device according to claim 1, wherein the coupling flanges (155a, 155b) comprise two or more coupling flanges (155a, 155b) formed in the respective body parts (153a, 153b) of the first member (150a) and the second member (150b). [3] A vehicle steering device according to claim 1 or 2, wherein the coupling flanges (155a, 155b) comprise an even number of two or more coupling flanges (155a, 155b) formed in the respective body parts (153a, 153b) of the first member (150a) and the second member (150b). [4] A vehicle steering device according to any one of the preceding claims, wherein the coupling flanges (155a, 155b) come into surface contact with each other when the body parts (153a, 153b) of the first member (150a) and the second member (150b) are coupled to each other. [5] Vehicle steering device according to one of the preceding claims, wherein the coupling projection (157) comprises: an insertion support portion (157a) connected to the coupling flange (155a, 155b) and supported on an inner peripheral surface of the coupling hole (159); and an outer support portion (157b) extending from the insertion support portion (157a) in a longitudinal direction and a radial direction and protruding from the coupling hole (159) to be supported on an outer surface of the coupling flange (155a, 155b) having the coupling hole (159). [6] The vehicle steering device according to claim 5, wherein the coupling projection (157) has a cutout portion (157c) symmetrically separating the insertion support portion (157a) and the outer support portion (157b). [7] A vehicle steering device according to claim 6, wherein a connecting web (157d) connecting the insertion support portion (157a) is provided at the cutout portion (157c). [8] Vehicle steering device comprising: a ball nut (125) having an inner circumferential screw groove (125a) arranged to face an outer circumferential screw groove (120a) of a rack (120), and having a first communication hole (127a) and a second communication hole (127b) penetrating an inner circumferential surface and an outer circumferential surface and arranged on a first side and a second side of the inner circumferential screw groove (125a); and a return pipe (150) having body parts (153a, 153b) formed of a first element (150a) and a second element (150b) which are symmetrical to each other to form a ball circulation path (151a, 151b) communicating with the first communication hole (127a) and the second communication hole (127b) with coupled inner surfaces, wherein a first end portion of the body part (153a, 153b) is coupled to the first communication hole (127a) and a second end portion of the body part (153a, 153b) is coupled to the second communication hole (127b) to circulate a ball, wherein coupling flanges (155a, 155b) which are coupled to face each other are provided on the respective outer surfaces of the body part (153a, 153b) of the first element (150a) and the second element (150b), wherein a coupling projection (157) is formed on one of the coupling flanges (155a, 155b) to protrude in a facing direction,and a coupling hole (159) into which the coupling projection (157) is fitted is formed in another of the coupling flanges (155a, 155b), wherein a fastening projection (161) is formed in one of the body parts (153a, 153b) of the first element (150a) and the second element (150b), and a fastening groove (163) into which the fastening projection (160) is inserted is formed in the other element. [9] A vehicle steering device according to claim 8, wherein the fastening projection (160) is formed in a partial region of the edge of the body part (153a, 153b) of the first member (150a) and the fastening groove (163) is formed in a remaining region of the edge. [10] A vehicle steering device according to claim 8 or 9, wherein the fastening projection (160) and the fastening groove (163) are fitted into each other and thereby come into surface contact with each other. [11] A vehicle steering device according to any one of claims 8 to 10, wherein the coupling flanges (155a, 155b) comprise two or more coupling flanges (155a, 155b) formed in the respective body parts (153a, 153b) of the first member (150a) and the second member (150b). [12] A vehicle steering device according to any one of claims 8 to 11, wherein the coupling flanges (155a, 155b) comprise an even number of two or more coupling flanges (155a, 155b) formed in the respective body parts (153a, 153b) of the first member (150a) and the second member (150b). [13] A vehicle steering device according to any one of claims 8 to 12, wherein the coupling flanges (155a, 155b) come into surface contact with each other when the body parts (153a, 153b) of the first member (150a) and the second member (150b) are coupled to each other. [14] A vehicle steering device according to any one of claims 8 to 13, wherein the coupling projection (157) comprises: an insertion support portion (157a) connected to the coupling flange (155a, 155b) and supported on an inner peripheral surface of the coupling hole (159); and an outer support portion (157b) extending from the insertion support portion (157a) in a longitudinal direction and a radial direction and protruding from the coupling hole (159) to be supported on an outer surface of the coupling flange (155a, 155b) having the coupling hole (159). [15] The vehicle steering device according to claim 14, wherein the coupling projection (157) has a cutout portion (157c) symmetrically separating the insertion support portion (157a) and the outer support portion (157b).

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