Steering device and energy absorption mechanism for steering device

Abstract

A steering device (1) comprises an inner tube (3), a drive unit (5), and an energy absorption unit (7). The inner tube (3) is provided in a column housing (9) so as to be movable relative to the column housing (9). The drive unit (5) comprises an output unit (11) and a main body unit (13) provided in the column housing (9), and drives the inner tube (3) by means of the output unit (11). The energy absorption unit (7) is unitized, is provided between the inner tube (3) and the drive unit (5), and is configured to absorb an impact force applied to the inner tube (3).

Description

Steering device and energy absorption mechanism for steering device

[0001] The present disclosure relates to a steering device and an energy absorption mechanism for the steering device.

[0002] Patent Document 1 describes a steering device having a structure in which a shock absorbing member and a retainer are fastened to an inner tube with rivets.

[0003] Japanese Patent Application Laid-Open No. 2022-152635

[0004] In the steering device of Patent Document 1, the impact absorbing member and the retainer are fastened to the inner tube with rivets, and since multiple parts need to be fastened together, assembly becomes complicated.

[0005] The present disclosure aims to provide a steering device and an energy absorption mechanism for the steering device that can improve the ease of assembling the energy absorption mechanism to the inner tube and the drive unit for moving the inner tube.

[0006] A steering device according to an embodiment includes an inner tube, a drive unit, and an energy absorbing unit. The inner tube is mounted in the column housing so as to be movable relative to the column housing. The drive unit includes an output unit and a main body mounted in the column housing, and drives the inner tube via the output unit. The energy absorbing unit is unitized and is disposed between the inner tube and the drive unit. A first predetermined portion is fixed to the inner tube, and a second predetermined portion is fixed to the output unit, thereby absorbing an impact force applied to the inner tube.

[0007] In the steering device according to the embodiment, the energy absorbing section includes an inner tube side member, a drive unit side member, and an impact force absorbing material. A predetermined portion of the inner tube side member is a first predetermined portion. A predetermined portion of the drive unit side member is a second predetermined portion. A first portion of the impact force absorbing material engages with the inner tube side member, and a second portion of the impact force absorbing material engages with the drive unit side member. When an impact force is applied to the inner tube, the impact force absorbing material is configured to deform and absorb the impact force.

[0008] In the steering device according to the embodiment, the inner tube side member and the drive unit side member are joined by a shear pin. When an impact force of a predetermined magnitude is applied to the inner tube, the shear pin breaks before the impact force absorbing material deforms, and the impact force absorbing material deforms after the shear pin breaks.

[0009] The steering device according to the embodiment includes a first flat portion fixed to the output portion and a second flat portion fixed to the drive portion-side member, and further includes an L-shaped bracket. The output portion and the drive portion-side member are joined together using the bracket.

[0010] The energy absorption mechanism of the steering device according to the embodiment includes an inner tube side member, a drive unit side member, and an impact force absorbing material. The inner tube side member, drive unit side member, and impact force absorbing material are unitized. The inner tube side member is installed on the inner tube, and the drive unit side member is installed on the output portion. A first portion of the impact force absorbing material engages with the inner tube side member. A second portion of the impact force absorbing material engages with the drive unit side member. The impact force absorbing material is configured to absorb an impact force applied to the inner tube by deformation. The inner tube engages with the column housing so as to be able to move relative to the column housing. The output portion is an output portion of the drive unit configured with a main body portion provided on the column housing, and drives the inner tube by the output portion.

[0011] According to the embodiment, it is possible to provide a steering device and an energy absorption mechanism for a steering device that can improve the ease of assembling the energy absorption mechanism to the inner tube and the drive unit for moving the inner tube.

[0012] Fig. 1 is a perspective view of a steering device according to an embodiment. Fig. 2 is an exploded perspective view of the steering device according to an embodiment. Fig. 3 is a diagram showing an inner tube side member, a drive unit side member, and an impact force absorbing material that constitute an energy absorption mechanism (energy absorption unit) of the steering device according to an embodiment. Fig. 4 is a view taken along arrow IV in Fig. 3.

[0013] A steering device 1 according to an embodiment will be described in detail below with reference to the drawings. The steering device 1 according to the embodiment is installed and used in a vehicle, for example. As shown in Figures 1 to 4, the steering device 1 includes an inner tube 3, an inner tube drive mechanism (drive unit) 5, and an energy absorption mechanism (energy absorption unit) 7.

[0014] Here, for ease of explanation, a predetermined direction in the steering device is defined as the X direction, a predetermined direction perpendicular to the X direction is defined as the Y direction, and a direction perpendicular to the X and Y directions is defined as the Z direction.

[0015] The inner tube 3 is formed in a tubular (for example, cylindrical) shape and is provided in the column housing 9 by engaging with the column housing 9 in a sliding manner. Due to this sliding, the inner tube 3 is able to move relative to the column housing 9 in the direction in which the central axis of the inner tube 3 extends (telescopic direction: Z direction).

[0016] The column housing 9 is formed in a generally cylindrical shape and is located outside the inner tube 3. The inner tube 3 is provided in the column housing 9 so as to pass through the column housing 9.

[0017] The inner tube drive mechanism 5 includes a moving body (output unit) 11 and a main body 13 that is integrally provided on the column housing 9. The inner tube 3 is driven by the moving body 11 that moves in the Z direction relative to the main body 13.

[0018] The energy absorbing mechanism 7 is unitized in advance and provided between the inner tube 3 and the movable body 11 of the inner tube drive mechanism 5. The energy absorbing mechanism 7 has a first predetermined portion 25 fixed to the inner tube 3 and a second predetermined portion 27 fixed to the movable body 11 of the inner tube drive mechanism 5. In this way, the energy absorbing mechanism 7 is configured to mitigate the impact force (see arrow A1 in FIG. 1 ) applied to the inner tube 3. In other words, the energy absorbing mechanism 7 is configured to absorb the energy of the impact force in the Z direction at the time of a secondary collision to mitigate the impact force.

[0019] The energy absorbing mechanism 7 is pre-assembled as a unit. That is, the energy absorbing mechanism 7 is assembled separately from the inner tube 3 and the inner tube drive mechanism 5.

[0020] The energy absorption mechanism 7 includes an inner tube side member 15, a drive unit side member (telescopic bracket) 17, and an impact force absorbing material (bending plate) 19, which are assembled as a unit. The inner tube side member 15 includes, for example, a release plate 21 and an adjustment plate (telescopic plate) 23.

[0021] A predetermined portion of the inner tube side member 15 is a first predetermined portion 25 that is fixed to the inner tube 3. A predetermined portion of the drive unit side member 17 is a second predetermined portion 27 that is fixed to the moving body 11 of the inner tube drive mechanism 5 via a bracket 29, for example.

[0022] A first portion 31 of the impact force absorbing material 19 engages with the inner tube side member 15 (detachment plate 21), and a second portion 33 of the impact force absorbing material 19 engages with the drive unit side member 17. When an impact force is applied to the inner tube 3, the impact force absorbing material 19 is configured to deform (e.g., plastically deform) to absorb the impact force.

[0023] As described above, the inner tube side member 15, the drive unit side member 17, and the impact force absorbing material 19 that constitute the energy absorption mechanism 7 are unitized in advance. In other words, the energy absorption mechanism 7 is assembled separately from the inner tube 3, the inner tube drive mechanism 5, and other components. The energy absorption mechanism 7 is then installed on the inner tube 3 and the inner tube drive mechanism 5 while maintaining the assembled state, and is able to function.

[0024] In the steering device 1, the inner tube side member 15 (detachment plate 21) and the drive unit side member 17 are joined (fastened) to each other by a plurality of (for example, three) shear pins 35 (see FIG. 4).

[0025] When an impact force of a predetermined magnitude is applied to the inner tube 3, the shear pin 35 breaks (shear fracture) and the impact force absorbing material 19 starts to deform (plastic deformation), and the connection between the inner tube side member 15 (detachment plate 21) and the drive unit side member 17 is released.

[0026] The energy value increases once when the shear pin 35 breaks, and then increases above the energy value at the time of breakage as the impact force absorbing material 19 undergoes plastic deformation, and then becomes constant when the plastic deformation is complete.

[0027] The steering device 1 is provided with a bracket 29. The bracket 29 joins the movable body 11 and the drive unit side member 17 of the inner tube drive mechanism 5 to each other. The bracket 29 includes a first flat plate-shaped portion 37 and a second flat plate-shaped portion 39. When viewed in the Z direction, the bracket 29 is formed in an L shape.

[0028] The first flat plate-shaped portion 37 is fixed to the movable body 11 of the inner tube drive mechanism 5. The second flat plate-shaped portion 39 is fixed to the drive unit side member 17 (second predetermined portion 27) of the energy absorption mechanism 7.

[0029] Here, the state in which the inner tube drive mechanism 5 on which the bracket 29 is installed is appropriately positioned and oriented relative to the energy absorbing mechanism 7 is referred to as the pre-bracket / drive unit installation state. In the pre-bracket / drive unit installation state, the bracket 29 and inner tube drive mechanism 5 are appropriately moved (for example, moved parallel) relative to the energy absorbing mechanism 7. As a result, the bracket 29 engages with the energy absorbing mechanism 7 (drive unit-side member 17) and is temporarily installed.

[0030] After this temporary installation, the bracket 29 and the drive unit side member 17 are integrated using fasteners such as bolts 41. In this way, the inner tube drive mechanism 5 can be easily installed on the energy absorption mechanism 7 using fasteners such as the bracket 29 and bolts 41, as described above. Also, the inner tube side member 15 can be easily installed on the inner tube 3 using fasteners such as bolts 43.

[0031] Here, the steering device 1 will be described in more detail.

[0032] As described above, the inner tube side member 15 includes the detachment plate 21 and the adjustment plate 23. The detachment plate 21 and the adjustment plate 23 are formed, for example, in the shape of a flat plate.

[0033] The thickness direction of the release plate 21 and the thickness direction of the adjustment plate 23 are aligned in the X direction. The release plate 21 and the adjustment plate 23 overlap each other. The adjustment plate 23 is located between the inner tube 3 and the release plate 21 in the X direction.

[0034] A recess 45 is provided in the center of the surface of the adjusting plate 23 facing the inner tube 3. The recess 45 extends over the entire length of the adjusting plate 23 in the Z direction. As a result, two protrusions 47 extending over the entire length of the adjusting plate 23 in the Z direction are formed on the surface of the adjusting plate 23 facing the inner tube 3. These two protrusions 47 come into contact with the side surfaces of the cylindrical inner tube 3, thereby stabilizing the posture of the inner tube side member 15 relative to the inner tube 3.

[0035] The detachment plate 21 is provided with an engaging portion that engages with the engaging portion of the drive unit side member 17. The detachment plate 21 and the drive unit side member 17 are engaged with each other at these engaging portions, so that when the shear pin 35 breaks, the detachment plate 21 can slide relative to the drive unit side member 17 and move in the Z direction. When the shear pin 35 is not broken, the detachment plate 21 and the drive unit side member 17 are integrated.

[0036] As already understood, the release plate 21 and the adjustment plate 23 are fixed to the inner tube 3 by bolts 43 .

[0037] The impact force absorbing material 19 comprises an impact force absorbing material main body 49 and a folded portion 51. The impact force absorbing material main body 49 is formed in a flat plate shape before being installed on the drive unit side member 17. The impact force absorbing material main body 49 comprises a wide portion 53 having a large dimension in the Y direction, and a narrow portion 55 having a small dimension in the Y direction. The folded portion 51 is formed by slightly extending the wide portion 53. The dimension of the folded portion 51 in the Y direction is equal to the dimension of the wide portion 53 in the Y direction.

[0038] As shown in FIG. 3 , the drive unit side member 17 is provided with a planar guide surface 57 , a protrusion 59 protruding from the guide surface 57 , and a contact surface 61 .

[0039] A state in which the impact force absorbing material 19 is installed on the drive unit side member 17 and the release plate 21 and the energy absorbing mechanism 7 is formed will be described.

[0040] The impact force absorbing material 19 is fixed to the detachment plate 21 at one longitudinal portion, that is, the folded portion 51 and the wide portion 53. More specifically, the wide portion 53 of the impact force absorbing material 19 is fixed to the detachment plate 21 by one of the pair of bolts 43. The folded portion 51 of the impact force absorbing material 19 is also fixed to the detachment plate 21 by fitting into a groove in the detachment plate 21.

[0041] The width direction of the impact force absorbing material 19 is the Y direction. When viewed in the Y direction, as shown in Figure 3, the long and slender narrow portion 55 of the impact force absorbing material 19 is bent in a semicircular arc shape at the middle portion in the longitudinal direction. The portion of the impact force absorbing material 19 excluding the middle portion of the narrow portion 55 extends long in the Z direction, and the thickness direction is the X direction.

[0042] 3, when viewed in the Y direction, one side of the protruding portion 59 is rounded in a semicircular arc, and the middle portion of the narrow portion 55 abuts against the rounded portion of the protruding portion 59 and bends in an arc. The radius of the arc of the narrow portion 55 is larger than the radius of the arc of the protruding portion 59. The portion of the narrow portion 55 of the impact force absorbing material 19 that extends from the arc-shaped portion on the opposite side to the wide portion 53 abuts against a flat abutment surface 61 of the drive unit-side member 17.

[0043] One widthwise end of the impact force absorbing material 19 abuts against the planar guide surface 57 of the drive unit side member 17. Furthermore, as shown in Fig. 3, a gap 63 is formed between the protruding portion 59 and the portion of the narrow width portion 55 of the impact force absorbing material 19 that extends from the arc-shaped portion on the side opposite to the wide width portion 53. In other words, the protruding portion 59 and the portion that extends from the arc-shaped portion on the side opposite to the wide width portion 53 are spaced apart from each other in the X direction.

[0044] 2, a through-hole 67 is formed in the first flat plate-shaped portion 37 of the bracket 29. A part of the movable body 11 fits into the through-hole 67, thereby mounting the bracket 29 on the movable body 11.

[0045] Here, a portion 65 of the bracket 29 (see FIG. 2 ) may be cut out to form a U-shaped through hole 67 of the bracket 29. Then, the bracket 29 is separated from the inner tube drive mechanism 5, and the position and posture of the bracket 29 relative to the inner tube drive mechanism 5 are set to an appropriate state. Next, the bracket 29 is translated. In this manner, the bracket 29 may be temporarily installed on the inner tube drive mechanism 5. In this temporary installation state, the bracket 29 is installed on the drive unit side member 17 of the energy absorption mechanism 7 using the bolts 41. In this manner, the inner tube drive mechanism 5 may be permanently installed on the energy absorption mechanism 7.

[0046] The rigidity and strength of the bracket 29, inner tube side member 15, and drive unit side member 17 are greater than the rigidity and strength of the shear pin 35 and impact force absorbing material 19. As a result, when an impact force of a predetermined magnitude is applied to the inner tube 3, the bracket 29, inner tube side member 15, and drive unit side member 17 will not break but will only undergo slight elastic deformation.

[0047] Here, the rigidity of the bracket 29 may be reduced so that both the impact force absorbing material 19 and the bracket 29 undergo plastic deformation after a predetermined magnitude of impact force is applied to the inner tube 3 and the shear pin 35 is broken. Note that even if the bracket 29 undergoes plastic deformation, it remains fixed to the inner tube drive mechanism 5 and the energy absorbing mechanism 7.

[0048] 2, the inner tube drive mechanism 5 includes a motor 69, a screw 71, and a nut 73 (moving body 11). The inner tube drive mechanism 5 also includes an L-shaped drive mechanism bracket 75 that supports the screw 71 and the nut 73 (moving body 11). The drive mechanism bracket 75 is fastened to the column housing 9 via a fixing bolt (not shown). In this way, the main body 13 of the inner tube drive mechanism 5 is fixed to the column housing 9.

[0049] Next, we will explain the operation of the steering device 1. When an impact force of a predetermined magnitude is applied to the inner tube 3, first, all of the shear pins 35 break. Next, the impact force absorbing material 19 deforms and absorbs the energy of the impact force.

[0050] The deformation of the impact force absorbing material 19 occurs when the folded portion 51, the wide portion 53, and the detachment plate 21 shown in Fig. 3 move to the left in Fig. 3 relative to the drive unit side member 17. The above-mentioned movement of the detachment plate 21, etc., causes the arc-shaped portion of the narrow portion 55 of the impact force absorbing material 19 that abuts against the protruding portion 59 of the drive unit side member 17 to shift. In other words, the length of the portion of the impact force absorbing material 19 that extends in the Z direction below the protruding portion 59 becomes longer, and the length of the portion of the impact force absorbing material 19 that extends in the Z direction above the protruding portion 59 becomes shorter.

[0051] In the steering device 1, the energy absorption mechanism 7 that absorbs the impact force during a secondary collision is unitized and can be easily installed between the inner tube 3 and the moving body 11 of the inner tube drive mechanism 5. This eliminates the need to fasten multiple parts simultaneously, improving the ease of assembling the energy absorption mechanism 7 to the inner tube 3 and the inner tube drive mechanism 5.

[0052] Furthermore, when it is desired to output a predetermined energy absorption load in the steering device 1, that is, when it is desired to adjust the value of the energy of the impact force to be absorbed, it is only necessary to change the unitized energy absorption mechanism 7. In this way, the steering device 1 can be easily changed to a predetermined energy absorption load.

[0053] In the steering device 1, the energy absorption mechanism 7 includes an inner tube side member 15, a drive unit side member 17, and an impact force absorbing material 19. The energy absorption mechanism 7 is fixed to the inner tube 3 and the moving body 11. The impact force absorbing material 19 is engaged with the inner tube side member 15 and the drive unit side member 17. When an impact force is applied to the inner tube 3, the impact force absorbing material 19 is configured to deform and absorb the impact force. This allows the steering device 1 to absorb impact forces with a simple configuration. Furthermore, the steering device 1 can change the amount of impact energy that can be absorbed by changing the specifications, such as the shape, of the impact force absorbing material 19.

[0054] In the steering device 1, the inner tube side member 15 and the drive unit side member 17 are joined by a shear pin 35. When an impact force of a predetermined magnitude is applied to the inner tube 3, the shear pin 35 breaks, and then the impact force absorbing material 19 deforms. This makes it possible to control the energy absorption load in the steering device 1. In other words, in the steering device 1, by appropriately changing the outer diameter, number, material, etc. of the shear pins 35, it is possible to change the amount of impact energy that can be absorbed by breaking the shear pins 35.

[0055] Furthermore, in the steering device 1, the movable body 11 of the inner tube drive mechanism 5 and the drive unit side member 17 are joined using an L-shaped bracket 29. This allows the energy absorption mechanism 7, the inner tube drive mechanism 5, and the bracket 29 to be assembled to the inner tube 3 from, for example, one direction, improving ease of assembly.

[0056] Here, the energy absorption mechanism 7 of the steering device 1 will be described again.

[0057] The energy absorption mechanism 7 of the steering device 1 includes an inner tube side member 15, a drive unit side member 17, and an impact force absorbing material 19, which are unitized. The inner tube side member 15 is attached to the inner tube 3. The drive unit side member 17 is attached to the output section 11. A first portion 31 of the impact force absorbing material 19 engages with the inner tube side member 15, and a second portion 33 of the impact force absorbing material 19 engages with the drive unit side member 17. The impact force absorbing material 19 deforms to absorb the impact force applied to the inner tube 3.

[0058] In the energy absorption mechanism 7 of the steering device 1, the inner tube 3 is engaged with the column housing 9 so as to be able to move relative to the column housing 9. The output portion 11 is the output portion 11 of the drive unit 5 that is configured with a main body portion 13 that is provided on the column housing 9, and the output portion 11 drives the inner tube 3.

[0059] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment.

[0060] The entire contents of Japanese Patent Application No. 2023-119055 (filing date: July 21, 2023) are incorporated herein by reference.

Claims

1. A steering device comprising: an inner tube provided in a column housing so as to be movable relative to the column housing; a drive unit having an output unit and a main body provided in the column housing, and driving the inner tube via the output unit; and an energy absorbing unit which is unitized and provided between the inner tube and the drive unit, and is configured to absorb an impact force applied to the inner tube by having a first predetermined portion fixed to the inner tube and a second predetermined portion fixed to the output unit.

2. A steering device as described in claim 1, wherein the energy absorbing section comprises an inner tube side member, a drive unit side member, and an impact force absorbing material, a predetermined portion of the inner tube side member being the first predetermined portion, a predetermined portion of the drive unit side member being the second predetermined portion, a first portion of the impact force absorbing material engaging with the inner tube side member and a second portion of the impact force absorbing material engaging with the drive unit side member, and wherein when an impact force is applied to the inner tube, the impact force absorbing material deforms to absorb the impact force.

3. A steering device as described in claim 2, wherein the inner tube side member and the drive unit side member are joined by a shear pin, and when an impact force of a predetermined magnitude is applied to the inner tube, the shear pin breaks before the impact force absorbing material deforms, and the impact force absorbing material deforms after the shear pin breaks.

4. A steering device as described in claim 2 or 3, further comprising a bracket formed in an L-shape, comprising a first flat portion fixed to the output portion and a second flat portion fixed to the drive portion side member, and wherein the output portion and the drive portion side member are joined using the bracket.

5. An energy absorption mechanism for a steering device comprising an inner tube side member, a drive unit side member, and an impact force absorbing material, the inner tube side member, the drive unit side member and the impact force absorbing material being unitized, the inner tube side member being installed on an inner tube, the drive unit side member being installed on an output section, a first portion of the impact force absorbing material engaging with the inner tube side member and a second portion of the impact force absorbing material engaging with the drive unit side member, the impact force absorbing material being configured to absorb the impact force applied to the inner tube by deformation, the inner tube engaging with a column housing so as to be able to move relative to the column housing, and the output section being an output section of a drive section comprising a main body section provided on the column housing, and the inner tube being driven by the output section.

Images