Vehicle steering apparatus

Abstract

The present embodiment provides a vehicle steering apparatus that can prevent a return pipe from disengaging from a ball nut, deforming, or damaging, regardless of continuous steering during driving, allow balls to correctly circulate through the return pipe to the ball nut, and prevent leakage of lubricant from the return pipe to correctly transmit steering assist force.

Description

Technical Field

[0001] The present embodiment relates to a vehicle steering device, and more particularly, to a vehicle steering device that can prevent a return tube from being detached from a ball nut, deformed, or damaged regardless of continuous steering during driving, allow balls to properly circulate to the ball nut through the return tube, and prevent lubricant from leaking from the return tube to properly transmit steering assist force. Background Art

[0002] A general vehicle steering device includes a steering system from a steering wheel to two opposing wheels and an auxiliary power mechanism that supplies steering auxiliary power to the steering system.

[0003] A typical vehicle steering device includes a motor controlled by an electronic controller, a motor pulley fixed to a motor shaft, a ball nut connected to a rack rod via balls, a return pipe coupled to the ball nut to allow the balls to circulate therein, a nut pulley coupled to an outer peripheral surface of the ball nut, and a belt coupled to the motor pulley and the nut pulley.

[0004] In a conventional vehicle steering device, the return tube may fall off, be deformed, or be damaged due to vibration generated when the balls circulate between the return tube and the ball nut by continuous steering during driving and impact from the road.

[0005] Furthermore, when the return pipe is not properly secured to the ball nut, the balls may not circulate properly, reducing the steering assist force and power transmission efficiency, resulting in failure in proper transmission of the steering assist force.

[0006] Furthermore, when the return pipe is circulated, leakage of the ball lubricant may occur, interfering with the smooth circulation of the balls, thereby causing discontinuous power transmission.

[0007] Therefore, research is needed to solve the above problems. Summary of the invention

[0008] In the above background technology, the present embodiment provides a vehicle steering device, which can prevent the return tube from detaching from the ball nut, deforming or being damaged regardless of continuous steering during driving, allow the balls to circulate correctly to the ball nut through the return tube, and prevent lubricant from leaking from the return tube to correctly transmit steering assist force.

[0009] According to this embodiment, a vehicle steering device can be provided, which includes: a ball nut, the ball nut having an inner peripheral thread groove arranged to face the outer peripheral thread groove of a rack rod and having a first connecting hole and a second connecting hole penetrating the inner peripheral surface and the outer peripheral surface and arranged on the first side and the second side of the inner peripheral thread groove; and a return pipe having a main body part, the return pipe is formed by a first component and a second component that are symmetrical to each other to form a ball circulation path connected to the first connecting hole and the second connecting hole in the inner surface of the connection, wherein the first end of the main body part is connected to the first connecting hole, and the second end of the main body part is connected to the second connecting hole to allow the balls to circulate, wherein connecting flanges facing each other are formed on the outer surfaces of the corresponding main bodies of the first component and the second component, and wherein a connecting protrusion protruding in the facing direction is formed on any one of the connecting flanges, and a connecting hole matching the connecting protrusion is formed in the other of the connecting flanges.

[0010] In this embodiment, the coupling flange may include two or more coupling flanges formed in respective body portions of the first member and the second member.

[0011] In the present embodiment, the coupling flange may include an even number of two or more coupling flanges formed in respective body portions of the first member and the second member.

[0012] In the present embodiment, the coupling flanges may surface-contact each other while main body portions of the first member and the second member are coupled to each other.

[0013] In the present embodiment, the respective body portions of the first member and the second member may have coupling surfaces that are in surface contact with each other while forming the ball circulation path.

[0014] In the present embodiment, an elastic member that is elastically compressed when the first member and the second member are coupled to each other may be coupled between coupling surfaces of the first member and the second member.

[0015] In this embodiment, the elastic member may be integrally formed with a coupling surface of the first member or the second member.

[0016] In this embodiment, the elastic member may be coupled or fused to a coupling surface of the first member or the second member by an adhesive.

[0017] In this embodiment, the connecting protrusion may include: an insertion support portion, which is connected to the connecting flange and supported on the inner circumferential surface of the connecting hole; and an outer support portion, which extends from the insertion support portion in the length direction and radial direction and protrudes outward from the connecting hole to support on the outer surface of the connecting flange having the connecting hole.

[0018] In this embodiment, the coupling protrusion may have a cutout portion symmetrically dividing the insertion support portion and the outer support portion.

[0019] In this embodiment, a connection rib connecting the insertion support portion may be provided on the cutout portion.

[0020] According to this embodiment, a vehicle steering device can be provided, which includes: a ball nut having an inner peripheral thread groove arranged to face the outer peripheral thread groove of a rack rod and having a first connecting hole and a second connecting hole penetrating the inner peripheral surface and the outer peripheral surface and arranged on the first side and the second side of the inner peripheral thread groove; and a return pipe having a main body part, the return pipe being formed by a first component and a second component symmetrical to each other to form a ball circulation path in the connected inner surface that is connected to the first connecting hole and the second connecting hole, wherein the first end of the main body part is connected to the first connecting hole, and the The second end of the main body part is connected to the second connecting hole to circulate the balls, wherein connecting flanges facing each other and connected are formed on the outer surfaces of the corresponding main body parts of the first member and the second member, wherein a connecting protrusion protruding in a facing direction is formed on any one of the connecting flanges, and a connecting hole matching with the connecting protrusion is formed in the other of the connecting flanges, wherein a fastening protrusion is formed in any one of the main body parts of the first member and the second member, and a fastening groove for inserting the fastening protrusion is formed in the other of the main body parts of the first member and the second member.

[0021] In the present embodiment, the fastening protrusion may be formed on the entire edge of the main body portion of the first member, and the fastening groove may be formed in the entire edge of the main body portion of the second member.

[0022] In the present embodiment, the fastening protrusion may be formed in a partial region of an edge of a main body portion of the first member, and the fastening groove may be formed in a remaining region of the edge.

[0023] In this embodiment, the fastening protrusion and the fastening groove may be fitted with each other while being in surface contact with each other.

[0024] In this embodiment, the coupling flange may include two or more coupling flanges formed in respective body portions of the first member and the second member.

[0025] In the present embodiment, the coupling flange may include an even number of two or more coupling flanges formed in respective body portions of the first member and the second member.

[0026] In the present embodiment, the coupling flanges may surface-contact each other while main body portions of the first member and the second member are coupled to each other.

[0027] In this embodiment, the connecting protrusion may include: an insertion support portion, which is connected to the connecting flange and supported on the inner circumferential surface of the connecting hole; and an outer support portion, which extends from the insertion support portion in the length direction and radial direction and protrudes outward from the connecting hole to support on the outer surface of the connecting flange having the connecting hole.

[0028] In this embodiment, the coupling protrusion may have a cutout portion symmetrically dividing the insertion support portion and the outer support portion.

[0029] According to the present embodiment, a vehicle steering device can be provided, which can prevent the return tube from detaching from the ball nut, deforming or being damaged regardless of continuous steering during driving, allow the balls to circulate properly to the ball nut through the return tube, and prevent lubricant from leaking from the return tube to properly transmit steering assist force. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other objects, features and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0031] Figure 1 is a view schematically showing a vehicle steering device according to the present embodiment;

[0032] Figure 2 and Figure 3 is a perspective view showing a portion of a vehicle steering device according to the present embodiment;

[0033] Figure 4 , Figure 5 and Figure 6 is an exploded perspective view showing a portion of a vehicle steering device according to the present embodiment;

[0034] Figure 7 and Figure 8 is a perspective view showing a portion of a vehicle steering device according to the present embodiment;

[0035] Fig. 9 and Fig.10 is a cross-sectional view showing a portion of a vehicle steering device according to the present embodiment;

[0036] Fig.11 , Fig.12 and Fig.13 is a perspective view showing a portion of a vehicle steering device according to the present embodiment;

[0037] Fig.14 is a front view showing a part of the vehicle steering device according to the present embodiment; and

[0038] Fig.15 It is along Fig.14 A cross-sectional view taken along line AA. DETAILED DESCRIPTION

[0039] In the following description of examples or embodiments of the present disclosure, reference will be made to the accompanying drawings, in which specific examples or embodiments that can be implemented are illustrated in a schematic manner, and in the accompanying drawings, the same reference numerals and symbols may be used to indicate the same or similar components, even if they are shown in different drawings from each other. In addition, in the following description of examples or embodiments of the present disclosure, when it is determined that a detailed description of the well-known functions and components incorporated herein may make the subject matter in some embodiments of the present disclosure unclear, the description will be omitted. Terms such as "including", "having", "comprising", "consisting of", and "consisting of" used herein are generally intended to allow the addition of other components unless the term is used together with the term "only". As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise.

[0040] Terms such as "first", "second", "A", "B", "(A)" or "(B)" may be used herein to describe elements of the present disclosure. Each of these terms is not used to define the nature, order, sequence or quantity of an element, but is merely used to distinguish the corresponding element from other elements.

[0041] When it is mentioned that a first element is “connected or coupled to”, “contacts or overlaps”, etc. a second element, it should be interpreted that not only the first element may be “directly connected or coupled to” or “directly contact or overlaps” the second element, but also a third element may be “interposed” between the first element and the second element, or the first element and the second element may be “connected or coupled to”, “contacts or overlaps”, etc. each other via a fourth element. Here, the second element may be included in at least one of the two or more elements that are “connected or coupled to”, “contacts or overlaps”, etc. each other.

[0042] When time-related terms such as “after,” “subsequently,” “next,” “before,” etc. are used to describe a process or operation of an element or configuration, or a flow or step in an operation, process, or method of manufacture, these terms may be used to describe a non-sequential or non-sequential process or operation unless the terms “directly” or “immediately” are used together.

[0043] Furthermore, when any dimension, relative dimension, etc. is mentioned, it should be considered that the numerical value or corresponding information (e.g., level, range, etc.) of an element or feature includes a tolerance or error range that may be caused by various factors (e.g., process factors, internal or external impact, noise, etc.), even when no relevant description is specified. In addition, the term "may" fully encompasses all meanings of the term "can".

[0044] Figure 1 : is a view schematically showing a vehicle steering device according to the present embodiment. Figure 2 and Figure 3 : is a perspective view showing a part of the vehicle steering device according to the present embodiment. Figure 4 , Figure 5 and Figure 6 : is an exploded perspective view showing a part of the vehicle steering device according to the present embodiment. Figure 7 and Figure 8 : is a perspective view showing a part of the vehicle steering device according to the present embodiment. Fig. 9 and Fig.10 is a cross-sectional view showing a part of the vehicle steering device according to the present embodiment. Fig.11 , Fig.12 and Fig.13 : is a perspective view showing a part of the vehicle steering device according to the present embodiment. Fig.14 : is a front view showing a part of the vehicle steering device according to the present embodiment. Fig.15 It is along Fig.14 A cross-sectional view taken along line AA.

[0045] As shown in the drawings, the vehicle steering device according to the present embodiment includes: a ball nut 125 having an inner peripheral thread groove 125a disposed to face the outer peripheral thread groove 120a of the rack bar 120, and having first and second communication holes 127a and 127b penetrating the inner and outer peripheral surfaces and disposed on the first and second sides of the inner peripheral thread groove 125a; and a return pipe 150 having body parts 153a and 153b, the return pipe 150 being formed by first and second members 150a and 150b symmetrical to each other to form ball circulation paths 151a and 151b communicating with the first and second communication holes 127a and 127b in the coupled inner surface. The first ends of the body parts 153a and 153b are coupled to the first communication hole 127a, and the second ends of the body parts 153a and 153b are coupled to the second communication hole 127b to circulate the balls. On the outer surfaces of the corresponding main body parts 153a and 153b of the first member 150a and the second member 150b, coupling flanges 155a and 155b facing each other for coupling are formed. A coupling protrusion 157 protruding in the facing direction is formed on any one of the coupling flanges 155a and 155b, and a coupling hole 159 cooperating with the coupling protrusion 157 is formed in the other of the coupling flanges.

[0046] In the vehicle steering device according to the present embodiment, the torque sensor 103 is coupled to one side of the steering shafts 102 and 106 connected to the steering wheel 101. When the driver manipulates the steering wheel 101, an electrical signal is sent from the torque sensor 103, the steering angle sensor 121, and the vehicle speed sensor 122 that detect the manipulation to the motor 113, so that two opposing wheels 115 are steered.

[0047] In the vehicle steering device according to the present embodiment, the upper steering shaft 102 is connected to the lower steering shaft 106 through a universal joint, so that steering is performed by a rack-and-pinion mechanism 116 having a pinion 108 and a rack 112 .

[0048] Here, the driving power of the motor 113 driven by the electronic control unit 111 is transmitted to the ball nut 125 through the motor 113 and the belt 150. The rack bar 120 coupled to the ball nut 125 slides axially through the ball. The tie rod 119 is coupled to two opposite sides of the rack bar 120, and the tie rod 119 is coupled to the knuckle arm 117 connected to the wheel 115 to steer the wheel 115.

[0049] An electric signal generated from the torque sensor 103 is transmitted to the ECU 111 , and the ECU 111 controls the motor 113 based on the electric signal received from the torque sensor 103 and electric signals received from a steering angle sensor 121 and a vehicle speed sensor 122 mounted to the vehicle.

[0050] Although examples of the torque sensor 103, the steering angle sensor 121, and the vehicle speed sensor 122 are provided for ease of description, an angle sensor, a motor position sensor, various radars or lidars, or an image sensor such as a camera may also be provided, which are not described in detail.

[0051] A power transmission structure is prepared on the outer peripheral surface of the rack bar 120 and the inner peripheral surface of the ball nut 125 so that the rack bar 120 slides axially, thereby generating a steering assist power. The power transmission structure includes: an outer peripheral thread groove 120a, which is spirally formed in the outer peripheral surface of the rack bar and has a semicircular or arcuate cross section; a ball (not shown) inserted into the outer peripheral thread groove 120a; and an inner peripheral thread groove 125a, which is spirally formed in the inner peripheral surface of the ball nut 125 to correspond to the outer peripheral thread groove 120a and has a semicircular or arcuate cross section.

[0052] In the ball nut 125 having an inner peripheral thread groove 125a formed in its inner peripheral surface, a first communication hole 127a and a second communication hole 127b penetrating the inner and outer peripheral surfaces are formed as a pair and are arranged to be spaced apart from each other along the inner peripheral thread groove 125a.

[0053] Therefore, the balls rolling along the outer and inner thread grooves 120a and 125a move from the first communicating hole 127a to the second communicating hole 127b and then circulate to the first communicating hole 127a through the ball circulation paths 151a and 151b of the return pipe 150.

[0054] The return pipe 150 is shaped substantially like a letter "U" and has a gentle curve from one end to an opposite end without a straight portion, and includes a pair of first and second members 150a and 150b that are symmetrical to each other with respect to a center line.

[0055] The return pipe 150 includes body parts 153a and 153b forming ball circulation paths 151a and 151b in the inner surfaces of the first and second members 150a and 150b coupled to each other. The first ends of the body parts 153a and 153b are coupled to the first communication hole 127a, and the second ends thereof are coupled to the second communication hole 127b.

[0056] Furthermore, a seating groove 126 for connecting the first communication hole 127 a and the second communication hole 127 b is formed in the outer peripheral surface of the ball nut 125 to seat the return pipe 150 in place.

[0057] The return pipe 150 may be formed of a plastic resin 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.

[0058] On the outer surfaces of the respective main body parts 153a and 153b of the first member 150a and the second member 150b, coupling flanges 155a and 155b facing each other for coupling are formed. A coupling protrusion 157 protruding in the facing direction is formed in any one of the coupling flanges 155a and 155b, and a coupling hole 159 coupled to the coupling protrusion 157 is formed in the other.

[0059] In other words, if the connecting protrusion 157 is formed in the connecting flange 155a of the main body portion 153a of the first member 150a, the connecting hole 159 is formed in the connecting flange 155b of the main body portion 153b of the second member 150b, so that the first member 150a and the second member 150b are connected to each other through the connecting protrusion 157 and the connecting hole 159.

[0060] The respective body portions 153a and 153b of the first and second members 150a and 150b may have two or more coupling flanges 155a and 155b.

[0061] The respective body portions 153a and 153b of the first and second members 150a and 150b may have an even number of two or more coupling flanges 155a and 155b.

[0062] If two or more coupling flanges 155a and 155b are formed in an even number, the first member 150a and the second member 150b may be formed by one mold, thereby reducing manufacturing costs and processes.

[0063] When the coupling flanges 155a and 155b and the body parts 153a and 153b of the first and second members 150a and 150b coupled to each other are in surface contact with each other, the water tightness of the first and second members 150a and 150b can be increased and leakage of lubricant when the balls circulate can be prevented.

[0064] The corresponding main body portions 153a and 153b of the first component 150a and the second component 150b may have connecting surfaces 154a and 154b that are in surface contact with each other while forming the ball circulation paths 151a and 151b, and the elastic member 160 that is elastically compressed when the first component 150a and the second component 150b are connected may be connected between the connecting surfaces 154a and 154b of the first component 150a and the second component 150b.

[0065] If the connecting protrusion 157 is fitted into the connecting hole 159, the elastic member 160 is elastically compressed while being supported on the connecting surfaces 154a and 154b of the first member 150a and the second member 150b, and in this state, if one end and the other end of the return pipe 150 are connected to the first connecting hole 127a and the second connecting hole 127b, the elastic member 160 can be further compressed and connected.

[0066] Therefore, the water tightness of the first member 150a and the second member 150b can be increased, and the leakage of the lubricant when the balls circulate can be prevented.

[0067] The elastic member 160 may be integrally formed with the coupling surfaces 154a and 154b of the first member 150a or the second member 150b, and may be coupled or fused to the coupling surfaces 154a and 154b of the first member 150a or the second member 150b by an adhesive.

[0068] Here, the elastic member 160 needs to be formed of a material that can absorb vibration and noise while having a certain degree of elasticity and rigidity, and can therefore be formed of an elastic material such as natural rubber (NR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene propylene terpolymer (EPDM), fluororubber (FPM), styrene butadiene rubber (SBR), chlorosulfonated polyethylene (CSM), polyurethane or silicone.

[0069] The connecting protrusion 157 formed to protrude in the connecting flanges 155a and 155b includes: an insertion support portion 157a, which is connected to the connecting flanges 155a and 155b and supported on the inner circumferential surface of the connecting hole 159; and an outer support portion 157b, which extends from the insertion support portion 157a in the length direction and the radial direction and protrudes outward from the connecting hole 159 to be supported on the outer surface of the connecting flanges 155a and 155b having the connecting hole 159.

[0070] In addition, the coupling protrusion 157 has a cutout portion 157c symmetrically dividing the insertion support portion 157a and the outer support portion 157b.

[0071] 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 face the cutout portion 157c, facilitating easy assembly.

[0072] In addition, if Fig.10 As shown, a connection rib 157d may be provided in the cutout portion 157c of the coupling protrusion 157 to connect the insertion support portion 157a.

[0073] The connecting rib 157d has a column or plate shape to connect the inner surface of the insertion support portion 157a. The provision of the connecting rib 157d increases the restoring force, by which the insertion support portion 157a and the outer support portion 157b are elastically deformed to move toward the cutout portion 157c when the coupling protrusion 157 is inserted into the coupling hole 159 and then restored to the initial position.

[0074] Therefore, if the outer supporting portion 157b passes through the coupling hole 159 and is then positioned on the outer surfaces of the coupling flanges 155a and 155b, the outer supporting portion 157b easily returns to the original shape, thereby maintaining the fastening strength at the correct position without falling off.

[0075] Meanwhile, the present embodiment may include: a ball nut 125 having an inner peripheral thread groove 125a disposed to face the outer peripheral thread groove 120a of the rack bar 120 and having first and second communication holes 127a and 127b penetrating the inner and outer peripheral surfaces and disposed at the first and second sides of the inner peripheral thread groove 125a; and a return pipe 150 having body parts 153a and 153b, the return pipe 150 being formed by first and second members 150a and 150b symmetrical to each other to form ball circulation paths 151a and 151b communicating with the first and second communication holes 127a and 127b in the coupled inner surface. The first ends of the body parts 153a and 153b are coupled to the first communication hole 127a, and the second ends of the body parts 153a and 153b are coupled to the second communication hole 127b to circulate the balls. On the outer surfaces of the respective main body parts 153a and 153b of the first member 150a and the second member 150b, coupling flanges 155a and 155b facing each other and coupling are formed. A coupling protrusion 157 protruding in the facing direction is formed on any one of the coupling flanges 155a and 155b, and a coupling hole 159 cooperating with the coupling protrusion 157 is formed in the other of the coupling flanges. A fastening protrusion 161 is provided in any one of the main body parts 153a and 153b of the first member 150a and the second member 150b, and a fastening groove 163 for inserting the fastening protrusion 161 is provided in the other.

[0076] Here, the ball nut 125 is the same as the above-mentioned ball nut, and will not be described in detail below. The following description mainly focuses on the differences from the above-mentioned configuration. Figures 11 to 15 Configuration shown.

[0077] Reference Figures 11 to 15 as well as Figures 2 to 10The return pipe 150 shown is provided with a fastening protrusion 161 in any one of the main body portions 153a and 153b of the first member 150a and the second member 150b, and is provided with a fastening groove 163 into which the fastening protrusion 161 is inserted in the other.

[0078] like Fig.11 As shown, the fastening protrusion 161 may be provided in the entire edge of the main body portion 153a of the first member 150a, and as shown in FIG. Fig.12 As shown, the fastening groove 163 may be provided in the entire edge of the body portion 153b of the second member 150b.

[0079] Therefore, when the first member 150a and the second member 150b are coupled, when the coupling protrusions 157 of the coupling flanges 155a and 155b are fitted into the coupling holes 159, the fastening protrusions 161 and the fastening grooves 163 of the body portions 153a and 153b are also coupled.

[0080] In addition, if Fig.13 As shown, the fastening protrusion 161 may be provided in a partial area of ​​an edge of the main body portion 153a of the first member 150a, and the fastening groove 163 may be provided in a remaining area of ​​the edge.

[0081] In this case, since the first member 150a and the second member 150b are formed in the same shape and can be formed using one mold, the manufacturing cost and process can be reduced.

[0082] The fastening protrusion 161 and the fastening groove 163 are coupled to each other while being in surface contact with each other. Therefore, the water tightness of the first member 150a and the second member 150b can be increased, and the leakage of the lubricant when the ball circulates can be prevented.

[0083] The respective body portions 153a and 153b of the first and second members 150a and 150b may have two or more coupling flanges 155a and 155b.

[0084] In addition, two or more coupling flanges 155a and 155b may be formed in the corresponding main body parts 153a and 153b of the first member 150a and the second member 150b in an even number. If two or more coupling flanges 155a and 155b are formed in an even number, the first member 150a and the second member 150b may be formed using one mold, thereby reducing manufacturing costs and processes.

[0085] Since the coupling flanges 155a and 155b are coupled to each other while in surface contact with each other, and the main body portions 153a and 153b of the first and second members 150a and 150b are coupled to each other, the water tightness of the first and second members 150a and 150b can be increased and leakage of lubricant when the balls circulate can be prevented.

[0086] The connecting protrusion 157 includes: an insertion support portion 157a, which is connected to the connecting flanges 155a and 155b and supported on the inner circumferential surface of the connecting hole 159; and an outer support portion 157b, which extends from the insertion support portion 157a in the length direction and the radial direction and protrudes outward from the connecting hole 159 to be supported on the outer surface of the connecting flanges 155a and 155b having the connecting hole 159.

[0087] 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 toward the cutout portion 157c, thereby facilitating assembly.

[0088] Meanwhile, support protrusions 152a and 152b are formed on both opposite ends of the return pipe 150. The support protrusions 152a and 152b protrude from the outer peripheral surface and are in close contact with each other when fitted into the first and second communication holes 127a and 127b.

[0089] The support protrusions 152a and 152b radially protrude from the outer peripheral surfaces of the main parts 153a and 153b of the return pipe 150, and when the return pipe 150 is assembled, the support protrusions 152a and 152b are elastically deformed and fit into the first connecting hole 127a and the second connecting hole 127b, maintaining the connection without falling off despite the vibration and external impact caused by the circulation of the ball.

[0090] Support protrusions 152 a and 152 b are formed on the first member 150 a at one end of the return pipe 150 , and are formed on the second member 150 b at the other end of the return pipe 150 .

[0091] In other words, since the support protrusions 152a and 152b are formed in semicircular shapes on one end and the other end of the return pipe 150, respectively, when the support protrusions 152a and 152b are broken during assembly, the fastening strength can be maintained while preventing debris or powder from entering the ball nut 125.

[0092] A bearing 140 coupled to a gear box (not shown) to support the rotation of the ball nut 125 is coupled to one outer peripheral side end of the ball nut 125, and a nut pulley 130 is coupled to the other outer peripheral side end of the ball nut 125. An inner peripheral surface of the nut pulley 130 is spaced apart from an outer peripheral surface of the ball nut 125 to form a space.

[0093] The nut pulley 130 connected 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 installed on the motor pulley 123 and the nut pulley 130 to transmit the rotational force from the motor 113 to the rack rod 120 through the ball nut 125, and the rack rod 120 moves left and right through the operation of the ball nut 125, thereby generating a steering assist force.

[0094] According to the present embodiment, a vehicle steering device can be provided, which can prevent the return tube from detaching from the ball nut, deforming or being damaged regardless of continuous steering during driving, allow the balls to circulate properly to the ball nut through the return tube, and prevent lubricant from leaking from the return tube to properly transmit steering assist force.

[0095] The above description is proposed to enable those skilled in the art to implement and use the technical ideas of the present disclosure, and is provided in the context of specific applications and their requirements. Various modifications, additions and substitutions to the described embodiments will be 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 present disclosure. The above description and accompanying drawings provide examples of the technical ideas of the present disclosure for illustrative purposes only. That is, the disclosed embodiments are intended to illustrate the scope of the technical ideas of the present disclosure. Therefore, the scope of the present disclosure is not limited to the embodiments shown, but is consistent with the widest scope consistent with the claims. The scope of protection of the present disclosure should be interpreted based on the attached claims, and all technical ideas within the scope of their equivalents should be interpreted as included within the scope of the present disclosure.

[0096] CROSS-REFERENCE TO RELATED APPLICATIONS

[0097] This application claims priority to Korean Patent Application No. 10-2023-0088127, filed on Jul. 7, 2023, which is hereby incorporated by reference for all purposes as if fully set forth herein.

Claims

1. A vehicle steering device, comprising: a ball nut having an inner peripheral thread groove disposed to face the outer peripheral thread groove of the rack bar and having first and second communication holes penetrating the inner and outer peripheral surfaces and disposed on first and second sides of the inner peripheral thread groove; as well as A return pipe having a main body portion, the return pipe being formed by a first member and a second member being symmetrical to each other so as to form a ball circulation path in the inner surface of the connection which is connected to the first connecting hole and the second connecting hole, wherein the first end of the main body portion is connected to the first connecting hole, and the second end of the main body portion is connected to the second connecting hole to allow the balls to circulate, wherein connecting flanges facing each other are formed on the outer surfaces of the corresponding main bodies of the first member and the second member, and wherein a connecting protrusion protruding in a facing direction is formed on any one of the connecting flanges, and a connecting hole cooperating with the connecting protrusion is formed in the other of the connecting flanges.

2. The vehicle steering device according to claim 1, wherein: The coupling flanges surface-contact each other while main body portions of the first and second members are coupled to each other.

3. The vehicle steering device according to claim 1, wherein: The coupling protrusion comprises: 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 extends from the insertion support portion in a length direction and a radial direction and protrudes outward from the coupling hole to be supported on an outer surface of the coupling flange having the coupling hole.

4. The vehicle steering device according to claim 3, wherein: The coupling protrusion has a cutout portion symmetrically dividing the insertion support portion and the outer support portion.

5. A vehicle steering device, comprising: a ball nut having an inner peripheral thread groove disposed to face the outer peripheral thread groove of the rack bar and having first and second communication holes penetrating the inner and outer peripheral surfaces and disposed on first and second sides of the inner peripheral thread groove; as well as A return pipe having a main body portion, the return pipe being formed by a first member and a second member symmetrical to each other to form a ball circulation path in the inner surface of the connection that is connected to the first connecting hole and the second connecting hole, wherein the first end of the main body portion is connected to the first connecting hole, and the second end of the main body portion is connected to the second connecting hole to allow the balls to circulate, wherein connecting flanges facing each other and connected are formed on the outer surfaces of the corresponding main bodies of the first member and the second member, wherein a connecting protrusion protruding in a facing direction is formed on any one of the connecting flanges, and a connecting hole matching the connecting protrusion is formed in the other of the connecting flanges, wherein a fastening protrusion is formed in any one of the main bodies of the first member and the second member, and a fastening groove for inserting the fastening protrusion is formed in the other of the main bodies of the first member and the second member.

6. The vehicle steering device according to claim 5, wherein: The fastening protrusion is formed in a partial area of ​​an edge of a main body portion of the first member, and the fastening groove is formed in a remaining area of ​​the edge.

7. The vehicle steering device according to claim 5, wherein: The fastening protrusion and the fastening groove are fitted with each other while being in surface contact with each other.

8. The vehicle steering device according to claim 5, wherein: The coupling flanges surface-contact each other while main body portions of the first and second members are coupled to each other.

9. The vehicle steering device according to claim 5, wherein: The coupling protrusion comprises: 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 extends from the insertion support portion in a length direction and a radial direction and protrudes outward from the coupling hole to be supported on an outer surface of the coupling flange having the coupling hole.

10. The vehicle steering device according to claim 9, wherein: The coupling protrusion has a cutout portion symmetrically dividing the insertion support portion and the outer support portion.

Images