STEERING COLUMN FOR AUTOMOTIVE

Abstract

According to various example embodiments, there is provided a steering column for an automotive vehicle including, an inner tube 100 surrounding a steering shaft 120, an outer tube 110 into which the inner tube 100 is inserted, a nut screw 230 mounted on the outside of the outer tube 110 and fixed to the inner tube 100, and a first lead screw 210 which is inserted into the nut screw 230 and screwed therein and is rotated by a motor. In the steering column for the automotive vehicle, the nut screw 230 and the inner tube 100 are transferred together by translational motion by rotation of the first lead screw 210.

Claims

1. A steering column for an automotive vehicle comprising: an inner tube (100) surrounding a steering shaft (120); an outer tube (110) into which the inner tube (100) is inserted; a nut screw (230) mounted on the outside of the outer tube (110) and fixed to the inner tube (100); and a first lead screw (210) which is inserted into the nut screw (230) and screwed therein and is rotated by a motor, wherein the nut screw (230) and the inner tube (100) are transferred together by translational motion by rotation of the first lead screw (210).

2. The steering column of claim 1, wherein a slot plate (101) is fixed to an inner surface of the inner tube (100).

3. The steering column of claim 2, wherein an inner tube slot (102a) is formed in the inner tube (100) in an axial direction, and in the slot plate (101), a slot (102) is formed in a portion corresponding to the inner tube slot (102a).

4. The steering column of claim 3, wherein the nut screw (230) is fixed to the inner tube (100) and the slot plate (101) by a lead bolt (103) passing through the inner tube slot (102a) and the slot (102) of the slot plate (101).

5. The steering column of claim 4, wherein in the outer tube (110), an outer tube slot (102b) is formed in a portion corresponding to the inner tube slot (102a) and the slot (102) of the slot plate (101), and the lead bolt (103) passes through the outer tube slot (102b) and is fixed to the nut screw (230).

6. The steering column of claim 4, wherein, in a state where a washer (104) is positioned between the lead bolt (103) and the inner tube (100) and a guide block (105) is positioned under the washer (104), the lead bolt (103) is screwed to the guide block (105).

7. The steering column of claim 6, wherein the guide block (105) comprises a guide block upper body (105b) and a guide block lower body (105a), a guide block hole (105c) is formed in the guide block upper body (105b), and the lead bolt (103) is screwed into the guide block hole (105c).

8. The steering column of claim 7, wherein the guide block lower body (105a) is formed with a width wider than a width of the slot (102) of the slot plate (101), and positioned under the slot plate (101).

9. The steering column of claim 8, wherein the guide block upper body (105b) protrudes upward through the slot plate (101).

10. The steering column of claim 9, wherein the guide block upper body (105b) is formed so that a width (W1) in a direction crossing the slot (102) is wider than a width (W2) of the slot (102).

11. The steering column of claim 10, wherein a frictional restraining force is formed with the washer (104) and the inner tube (100) by a bolt clamping force of the lead bolt (103) and the guide block (105), and when a stow mode is operated, the lead bolt (103), the washer (104), and the inner tube (100) are translated together according to the translational motion of the nut screw (230).

12. The steering column of claim 11, wherein, when the automotive vehicle crashes to absorb an impact energy, in a state where the lead bolt (103), the washer (104), and the guide block (105) restrained to the first lead screw (210) are fixed, the impact energy is absorbed as a relative displacement occurs between an outer surface of the guide block upper body (105b) of the guide block (105) and the slot (102) of the slot plate (101).

13. The steering column of claim 12, wherein a step (d) is formed between the washer (104) and the inner tube (100).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 is a schematic diagram illustrating a structure of a steering column for an automotive vehicle according to an example embodiment;

[0031] FIG. 2 is a diagram illustrating a state in which a steering column is contracted by a telescope function with a relative movement of an inner tube and an outer tube of the steering column of FIG. 1;

[0032] FIG. 3 is a diagram illustrating a state in which a slot plate is mounted on an inner surface of an inner tube of a steering column according to an example embodiment;

[0033] FIG. 4 is a diagram illustrating the slot plate of FIG. 3 and its related components; FIG. 5 is a diagram illustrating a structure of a guide block mounted on a slot of the slot plate of FIG. 3;

[0034] FIG. 6 is a cross-sectional view illustrating an internal structure of the steering column of FIGS. 1 and 2;

[0035] FIG. 7 is a partially enlarged view of the cross-sectional view of FIG. 6 to illustrate components involved when an impact energy is absorbed;

[0036] FIG. 8 is a graph illustrating a load change according to impact stroke when an impact energy is absorbed; and

[0037] FIG. 9 is a diagram illustrating structure of an inner tube and a washer in a coupling relationship with a slot plate.

DETAILED DESCRIPTION

[0038] Hereinafter, a steering column for an automotive vehicle according to example embodiments will be described in detail with reference to FIGS. 1 to 9.

[0039] FIG. 1 illustrates a schematic structure of a steering column for an automotive vehicle according to an example embodiment, and FIG. 2 illustrates a state in which the steering column is contracted by a telescope function having a relative movement of an inner tube and an outer tube of the steering column of FIG. 1.

[0040] As described with reference to FIG. 1, the steering column for the automotive vehicle according to an example embodiment includes an inner tube 100 of a hollow tube which is formed an outside of a steering shaft 120 and surrounds the steering shaft 120 connected to a steering wheel, and an outer tube 110 having an inner diameter larger than an outer diameter of the inner tube 100 so that the inner tube 100 may be inserted therein. One end of the inner tube 100 is inserted into one end of the outer tube 110.

[0041] In the steering column, a driver may adjust a degree of protrusion and an inclination angle of the steering wheel to suit his/her height or body type. Exemplarily, in order to reduce the degree of protrusion of the steering wheel toward the driver, when stow mode is operated, a locking state of the steering column is released using an adjustment lever (not shown), and a state in which the steering column is contracted by the inner tube 100 performing translational motion in the outer tube 110 is illustrated in FIG. 2.

[0042] A nut screw 230 and a first lead screw 210 that enable an axial direction movement of the inner tube 100 are mounted the outside of the steering column. The nut screw 230 is fixed to the inner tube 100 by a lead bolt 103 (see FIG. 6) via a first fixing block 240 (see FIG. 6). The lead bolt 103 is screwed to a guide block 105 passing through a slot formed in the inner tube 100 and the outer tube 110 and mounted on an inner surface of the inner tube 100 (see FIGS. 3 and 4). As a result, the lead bolt 103 is fixed to the inner tube 100.

[0043] The nut screw 230 is coupled to the first lead screw 210 which is inserted into the nut screw 230 and screwed therein. The first lead screw 210 is connected to a second lead screw 220, and the second lead screw 220 is connected to a speed reducer 200. The second lead screw 220 performs a rotational motion through the speed reducer 200 by a rotational force of a motor, and the first lead screw 210 connected thereto rotates and the nut screw 230 which is screwed thereto performs translational motion in the direction toward the speed reducer 200. As the nut screw 230 performs the translational motion, the inner tube 100 which is fixed thereto is transferred together by the translational motion with the nut screw 230.

[0044] A specific nut is screwed to the outside of the second lead screw 220, and the specific nut is fixed to a second fixing block 250. The second fixing block 250 is fixed to a separate intermediate tube (not shown in the drawings) which is coupled to the inner tube 100 in the axial direction inside the outer tube 110. Accordingly, when the second lead screw 220 is rotated by the speed reducer, the intermediate tube and the inner tube 100 fixed thereto are simultaneously transferred.

[0045] The second lead screw 220 may have one thread, and the first lead screw 210 may have two threads and have a lead twice as long as that of the second lead screw 220. In this way, a transport distance of the nut screw 230 may be doubled compared to a transport distance of the second fixing block 250 by the rotational force of the motor.

[0046] Hereinafter, a steering column structure for impact energy absorption in an automotive crash will be described with reference to FIGS. 3 to 7.

[0047] FIG. 3 illustrates a state in which a slot plate is mounted on an inner surface of an inner tube of the steering column according to an example embodiment, FIG. 4 illustrateds the slot plate of FIG. 3 and related components, and FIG. 5 illustrates structure of a guide block mounted in a slot of the slot plate of FIG. 3.

[0048] First, descriptions will be provided with reference to FIGS. 3 and 4. The steering shaft 120 is built-in inside the inner tube 100 formed of a hollow tube, and a slot plate 101 is fixed to an inner surface of the inner tube 100 by a plurality of bolts 106. A slot 102 is formed in the slot plate 101 by a predetermined distance. In the inner tube 100 corresponding to the slot 102 of the slot plate 101, an inner tube slot 102a similar thereto is formed. Since a plurality of screw holes 107 are formed in the slot plate 101, and a plurality of inner tube holes 107a are formed at positions corresponding of the inner tube 100, the plurality of bolts 106 pass through the inner tube holes 107a and the screw holes 107 and are screwed, so that the slot plate 101 is fixed to the inner surface of the inner tube 100. In addition, in the outer tube 110, an outer tube slot 102b (see FIGS. 1 and 2) is formed at positions corresponding to the slot plate 101, the slot 102 and the inner tube slot 102a.

[0049] In addition, referring to FIG. 6, the nut screw 230 is fixed to the inner tube 100 and the slot plate 101 by an outer tube slot 102b, the inner tube slot 102a, and the lead bolt 103 passing through the slot 102 of the slot plate 101 via the first fixing block 240 fixed to the outside of the nut screw.

[0050] Referring to FIGS. 3 to 6, in a state where a washer 104 is positioned between the lead bolt 103 and the inner tube 100, and the guide block 105 is positioned directly under the washer 104, the lead bolt 103 is screwed to the guide block 105. The guide block 105 includes a guide block upper body 105b and a guide block lower body 105a. A guide block hole 105c is formed in the guide block upper body 105b, so that the lead bolt 103 is screwed into the guide block hole 105c. The guide block lower body 105a is formed with a width wider than a width of the slot 102 of the slot plate 101, and thus the guide block upper body 105b penetrates the slot plate 101 and protrudes upward, but the guide block lower body 105a is coupled by the lead bolt 103 in a state positioned under the slot plate 101.

[0051] As described above, the slot plate 101 is assembled on the inner surface of the inner tube 100 to form a mechanism for absorbing an impact energy when the automotive vehicle crashes, and since the energy absorbing mechanism is formed on the inner surface of the inner tube 100, interference with a package outside of the steering column may be avoided during an energy absorption operation by the automotive crash. Further, by forming an impact energy absorbing structure using an inner space of the steering column, there is no need to secure a separate space for impact energy absorption outside the steering column, which makes the structure compact.

[0052] Referring to FIGS. 6 and 7, how a steering column operates during the stow mode operation and automotive crash energy absorbing load operation will be described. FIG. 6 is a cross-sectional view illustrating an internal structure of the steering column of FIGS. 1 and 2, and FIG. 7 is a partially enlarged view of the cross-sectional view of FIG. 6 to illustrate components involved when an impact energy is absorbed.

[0053] The stow mode operation will be described first. By rotation of the first lead screw 210, the lead bolt 103 restrained with the nut screw 230 perform translational motion. The washer 104 and parts of the inner tube 100 have a frictional restraining force by a bolt clamping force of the lead bolt 103 and the guide block 105, and when the stow mode is operated, the parts perform translational motion together.

[0054] In the case that an automotive vehicle crashes and absorbs an impact energy, an energy absorbing load operation will be described. An impact load is generated in the left direction in FIGS. 6 and 7 on the inner tube 100 and the slot plate 101 assembled by the plurality of bolts 106. At this time, the lead bolt 103, the washer 104, and the guide block 105 restrained to the first lead screw 210 are fixed without moving. The impact energy is absorbed as a relative displacement occurs between an outer surface of the guide block upper body 105b of the fixed guide block 105 and the slot 102 of the slot plate 101. To this end, the guide block upper body 105b is formed so that a width W1 in a direction crossing the slot 102 is wider than a width W2 of the slot 102.

[0055] The relative displacement between the guide block 105 and the slot 102 of the slot plate 101 as above occurs while overcoming load due to resistance existing therebetween, and by variously changing the dimension of the slot 102 of the slot plate 101, it is possible to facilitate tuning of an energy absorbing load.

[0056] FIG. 8 illustrates a change in load according to displacement or impact stroke that occurs during an automotive crash. At the beginning, the load abruptly increases then a peak appears, and after that, the load decreases. As the guide block 105 proceeds along the slot 102 of the slot plate 101, a running load which gradually increases and then becomes constant is formed. Here, since the impact stroke is determined by a length of the slot 102 of the slot plate 101, it does not change even if the inner tube 100 is transported to be contracted in the stow mode.

[0057] An initial peak load is formed by a frictional restraining force between the washer 104 and parts of the inner tube 100 according to the bolt clamping force of the lead bolt 103 and the guide block 105. On the other hand, the running load is formed by a resistive force according to a thickness of the slot plate 101 and a width dimension of the slot 102. Accordingly, the initial peak load may be adjusted by a clamping force of the lead bolt 103, and the running load may be adjusted by the thickness of the slot plate 101 and the width dimension of the slot 102.

[0058] FIG. 9 illustrates structure of an inner tube and a washer in a coupling relationship with a slot plate. A step d may be formed between the washer 104 and a running surface of the inner tube 100. By forming the step d in this way, it is possible to release a friction force between the washer 104 and the inner tube 100 when a running load section starts past a peak load. The running load may also be adjusted by the step d.

[0059] The above description is merely illustrative of the technical spirit of the present disclosure, and various modifications and variations would be possible without departing from the essential characteristics of the present disclosure by those skilled in the art to which the present disclosure pertains. Therefore, the example embodiments disclosed in the present disclosure are intended to explain, not to limit the technical spirit of the invention, but to explain it, and the scope of technical ideas of the invention is not limited by these example embodiments. The protection scope of the present disclosure should be construed by the appended claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present disclosure.

Explanation of Reference Numerals

[0060] 100: Inner tube

[0061] 101: Slot plate

[0062] 102: Slot

[0063] 102a: Inner tube slot

[0064] 103: Lead bolt

[0065] 104: Washer

[0066] 105: Guide block

[0067] 105a: Guide block lower body

[0068] 105b: Guide block upper body

[0069] 105c: Guide block hole

[0070] 106: Bolt

[0071] 107: Screw hole

[0072] 107a: Inner tube hole

[0073] 110: Outer tube

[0074] 120: Steering shaft

[0075] 200: Speed reducer

[0076] 210: First lead screw

[0077] 220: Second lead screw

[0078] 230: Nut screw

[0079] 240: First fixing block

[0080] 250: Second fixing block