Steering system

Abstract

The present invention provides a steering device that improves the ease of assembling an energy absorption mechanism to the inner tube and the drive unit for moving the inner tube. [Solution] The steering device 1 comprises a column housing 4 supported by the vehicle body, an inner tube 5 provided to be axially movable relative to the column housing 4, a drive unit 10 supported by the column housing 4 and driving the inner tube 5 in the axial direction, an energy absorption mechanism 8 which is unitized and provided between the inner tube 5 and the drive unit 10, with a first fixing portion 25 fixed to the inner tube 5 and a second fixing portion 27 fixed to the drive unit 10, configured to absorb impact forces applied to the inner tube 5, and a support portion 80 for supporting the bracket 17 of the unitized energy absorption mechanism 8 on the column housing 4.

Description

Technical Field

[0001] The present invention relates to a steering device.

Background Art

[0002] Conventionally, a steering device having a structure in which a shock absorbing member and a retainer are fastened to an inner tube with a rivet has been shown (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the conventional steering device, a shock absorbing member and a retainer are fastened to an inner tube with a rivet, and since it is necessary to fasten a plurality of parts simultaneously, the assembly becomes complicated and the assemblability is poor.

[0005] The present invention has been made in view of the problems of such conventional techniques. And the object of the present invention is to provide a steering device capable of improving the assemblability of an energy absorption mechanism to an inner tube and a drive unit for moving the inner tube.

Means for Solving the Problems

[0006] A steering device according to an aspect of the present invention comprises a column housing supported by the vehicle body, an inner tube provided to be axially movable relative to the column housing, and a drive unit supported by the column housing for driving the inner tube in the axial direction. The steering device includes an energy absorption mechanism which is unitized and provided between the inner tube and the drive unit, with a first fixing portion fixed to the inner tube and a second fixing portion fixed to the drive unit, thereby absorbing the impact force applied to the inner tube. The steering device includes a support portion for supporting the bracket of the unitized energy absorption mechanism on the column housing. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a steering device that can improve the ease of assembling an energy absorption mechanism to an inner tube and a drive unit for moving the inner tube. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing an example of a steering device according to this embodiment. [Figure 2] This is an enlarged cross-sectional view of the main part, showing the cross-section along line AA in Figure 1. [Figure 3] This is a perspective view showing the device with the energy absorption mechanism installed. [Figure 4] This is a schematic perspective view of a modularized energy absorption mechanism. [Figure 5] Figure 3 is a perspective view showing a partially decomposed energy absorption mechanism. [Figure 6] This is a decomposed perspective view of the energy absorption mechanism. [Figure 7] Figure 6 is a schematic perspective view of the telescopic bracket as seen from the opposite side. [Modes for carrying out the invention]

[0009] The steering device according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios.

[0010] In Figure 1, arrow FR indicates the front of the vehicle, and arrow RR indicates the rear of the vehicle.

[0011] The steering device 1 according to this embodiment is also called an electric steering device and is used, for example, when installed in a vehicle. As shown in Figures 1 to 3, the steering device 1 is configured to include a fixed bracket 2 fixed to the vehicle body and a column jacket 3 that is supported by the fixed bracket 2 so as to be able to swing in the vertical direction of the vehicle body.

[0012] Furthermore, the steering device 1 includes a steering shaft 7 housed within the column jacket 3, to which a steering wheel (not shown) is connected at its rear end. In addition, the steering device 1 includes a drive unit (telescopic mechanism) 10 driven by an electric motor (not shown) and an energy absorption mechanism 8.

[0013] The fixing bracket 2 is integrally composed of a bracket body 2a and a pair of side wall portions 2b that extend downward from the bracket body 2a and are positioned on both the left and right sides of the pivoting support portion of the column jacket 3. The bracket body 2a extends in the longitudinal direction of the vehicle body and is fixed to the vehicle body. The side wall portions 2b extend in the longitudinal direction of the vehicle body, similar to the bracket body 2a.

[0014] The column jacket 3 comprises a cylindrical column housing 4 and a cylindrical inner tube 5 inserted into the column housing 4 so as to be axially movable relative to it. The column housing 4 is also called the lower jacket and is located on the front side of the vehicle body relative to the fixing bracket 2. On the other hand, the inner tube 5 is also called the upper jacket and is housed within the column housing 4 and is supported so as to be axially movable relative to the column housing 4.

[0015] The telescopic mechanism 10 is configured to include a moving body 11 and a main body (housing) 13 that is integrally provided (fixed) to the column housing 4. And the inner tube 5 is driven (moved) in the vehicle longitudinal direction by the moving body 11 that moves in the vehicle longitudinal direction with respect to the housing 13.

[0016] The energy absorption mechanism 8 is pre-unified (integrated) and provided between the inner tube 5 and the moving body 11 of the telescopic mechanism 10. The energy absorption mechanism 8 is configured such that the first fixing portion 25 is fixed to the inner tube 5 and the second fixing portion 27 is fixed to the moving body 11 of the telescopic mechanism 10. Thereby, it is configured to mitigate the impact force applied to the inner tube 5. That is, it is configured to absorb the energy of the impact force in the vehicle longitudinal direction during a secondary collision and mitigate the impact force.

[0017] Since the energy absorption mechanism 8 is pre-unified, the energy absorption mechanism 8 is assembled separately from the inner tube 5 and the telescopic mechanism 10.

[0018] The energy absorption mechanism 8 is configured to include an inner tube side member 15, a drive unit side member (telescopic bracket) 17, and an impact force absorbing material (bending plate) 19. The inner tube side member 15 is composed of, for example, a detachment plate 21 and a telescopic plate 23.

[0019] A predetermined portion of the inner tube side member 15 serves as the first fixing portion 25 of the energy absorption mechanism 8 that is fixed to the inner tube 5. A predetermined portion of the telescopic bracket 17 serves as the second fixing portion 27 of the energy absorption mechanism 8 that is fixed to the moving body 11 of the telescopic mechanism 10 via, for example, a bracket 29.

[0020] One part (first part) 31 of the bending plate 19 engages with the inner tube side member 15 (detachment plate 21), and the other part (second part) 33 of the bending plate 19 engages with the telescopic bracket 17. And when an impact force is applied to the inner tube 5, the bending plate 19 is configured to deform (for example, plastic deformation) to absorb the impact force.

[0021] As described above, the inner tube side member 15, the telescopic bracket 17, and the bending plate 19 that constitute the energy absorption mechanism 8 are unitized in advance. That is, the energy absorption mechanism 8 is assembled separately from the inner tube 5, the telescopic mechanism 10, and others (see FIG. 4). And while maintaining the assembled state, the energy absorption mechanism 8 is assembled to the inner tube 5 and the telescopic mechanism 10 to exert its function.

[0022] Also, in the steering device 1, the inner tube side member 15 (detachment plate 21) and the telescopic bracket 17 are joined (connected) to each other by a plurality of (for example, four) shear pins. For this reason, a first press-fitting hole 21a for press-fitting the shear pin is formed in the detachment plate 21 (see FIGS. 5 and 6), and a second press-fitting hole 17a for press-fitting the shear pin is formed in the telescopic bracket 17 (see FIG. 7).

[0023] When an impact force of a predetermined magnitude is applied to the inner tube, the shear pin press-fitted into the first press-fitting hole 21a and the second press-fitting hole 17a breaks (shear fracture) and at the same time, the bending plate 19 starts to deform (plastic deformation). And the engagement between the inner tube side member 15 (detachment plate 21) and the telescopic bracket 17 is released.

[0024] The energy value increases once when the shear pin breaks, and then increases again as the bending plate 19 undergoes plastic deformation, exceeding the energy value at the time of fracture. After that, the energy value becomes constant as the plastic deformation is completed.

[0025] As shown in Figure 1, the steering device 1 is provided with a bracket 29. The bracket 29 connects (fixes) the movable body 11 of the telescopic mechanism 10 and the telescopic bracket 17 to each other. The bracket 29 is composed of a first flat plate portion 35 and a second flat plate portion 37. When viewed in the front-rear direction of the vehicle body, the bracket 29 is formed in an L-shape.

[0026] The first flat plate portion 35 is fixed to the movable body 11 of the telescopic mechanism 10. The second flat plate portion 37 is fixed to the telescopic bracket 17 (second fixed portion 27) of the energy absorption mechanism 8.

[0027] Here, the state in which the telescopic mechanism 10 on which the bracket 29 is installed is positioned and oriented appropriately relative to the energy absorption mechanism 8 is defined as the state before bracket and drive unit installation. In the state before bracket and drive unit installation, the L-shaped bracket 29 and the telescopic mechanism 10 are moved appropriately relative to the energy absorption mechanism 8 (for example, by translation). As a result, the L-shaped bracket 29 engages with the energy absorption mechanism 8 (telescopic bracket 17) and is temporarily installed.

[0028] From this temporarily installed state, the L-shaped bracket 29 and the telescopic bracket 17 are integrated by using fasteners such as bolts 39. Thus, as described above, the installation of the energy absorption mechanism 8 onto the telescopic mechanism 10 can be easily done using the L-shaped bracket 29 and fasteners such as bolts 39. Furthermore, the installation of the inner tube side member 15 onto the inner tube 5 can be easily done using bolts 41 and fasteners 43, etc.

[0029] Now, let's explain the steering device 1 in more detail.

[0030] In the steering device 1, a support portion 80 is provided for supporting the bracket (telescopic bracket 17) of the unitized energy absorption mechanism 8 on the column housing 4. The support portion 80 is configured to have a guide portion 81 formed on the column housing 4 so as to extend along the longitudinal direction (axial direction) of the vehicle body, and a lower recess 87 formed on the telescopic bracket 17 of the energy absorption mechanism 8, which engages with the guide portion 81 from below and is formed to restrain the movement of the guide portion 81 in the vehicle body width direction.

[0031] In the steering device 1, the guide portion 81 is composed of a first projection 83 that protrudes outward in the vehicle width direction from the column housing 4, and a second projection 85 that protrudes downward from the tip of the first projection 83 (see Figure 2). On the other hand, the lower recess 87 is composed of a recess 89 formed in the telescopic bracket 17 and a U-shaped member 91, for example, made of metal, that is mounted in this recess 89 (see Figures 2 and 7).

[0032] Furthermore, the support portion 80 is formed on the telescopic bracket 17 of the energy absorption mechanism 8, is located above the lower recess 87, and has an upper projection 93 that engages with the guide portion 81 from above. This upper projection 93 protrudes inward from the telescopic bracket 17 in the vehicle width direction (see Figures 2 and 7).

[0033] By forming the aforementioned support portion 80, when assembling the telescopic bracket 17 to the column housing 4, the telescopic bracket 17 can be slid from either the front-rear direction of the vehicle and engaged with the column housing 4 for assembly. This makes it easy to install the energy absorption mechanism 8 to the column housing 4 using the support portion 80 (guide portion 81, lower recess 87). Furthermore, by forming the aforementioned support portion 80, this support portion 80 (guide portion 81, lower recess 87) also functions as a guide against movement in the front-rear direction (axial direction) of the vehicle body during energy absorption, thus enabling stable energy absorption. In addition, since the movement of the guide portion 81 in the vehicle body width direction is restrained by the lower recess 87, it is possible to suppress the movement of the telescopic bracket 17 in the vehicle body width direction during energy absorption (when the engagement between the release plate 21 and the telescopic bracket 17 is released).

[0034] The support portion 80 further includes an upper projection 93, which allows the guide portion 81 to be sandwiched vertically by the lower recess 87 and the upper projection 93, enabling the telescopic bracket 17 to be slid into the column housing 4 from either the front or rear direction of the vehicle. This makes it easy to install the energy absorption mechanism 8 into the column housing 4 using the support portion 80 (guide portion 81, lower recess 87, and upper projection 93). Furthermore, when energy is absorbed (when the engagement between the release plate 21 and the telescopic bracket 17 is released), the upper projection 93 contacts the upper surface of the guide portion 81, preventing the telescopic bracket 17 from moving downward due to its own weight.

[0035] As described above, the inner tube side member 15 is composed of a release plate 21 and a telescopic plate 23. The release plate 21 and the telescopic plate 23 are formed, for example, in a flat plate shape.

[0036] As shown in Figures 3 to 6, the thickness direction of the detachment plate 21 and the thickness direction of the telescopic plate 23 coincide and are in the vehicle width direction (left-right direction). The detachment plate 21 and the telescopic plate 23 overlap each other, and the telescopic plate 23 is located between the inner tube 5 and the detachment plate 21 in the vehicle width direction.

[0037] A recess 45 is provided in the center of the inner tube 5 side of the telescopic plate 23. The recess 45 extends along the entire length of the telescopic plate 23 in the longitudinal direction of the vehicle body. As a result, two protrusions 47 are formed on the inner tube 5 side of the telescopic plate 23, extending along the entire length of the telescopic plate 23 in the longitudinal direction of the vehicle body. These two protrusions 47 contact the side surface of the cylindrical inner tube 5, thereby stabilizing the position of the inner tube side member 15 relative to the inner tube 5. A frame-shaped member 24 (see Figures 5 and 6) may be attached to the telescopic plate 23.

[0038] The release plate 21 is provided with an engaging portion that engages with the engaging portion of the telescopic bracket 17. The release plate 21 and the telescopic bracket 17 are engaged with each other at these engaging portions, allowing the release plate 21 to slide relative to the telescopic bracket 17 and move in the longitudinal direction of the vehicle when the shear pin breaks. When the shear pin is not broken, the release plate 21 and the telescopic bracket 17 are integrated.

[0039] As already understood, the detachable plate 21 and the telescopic plate 23 are fixed to the inner tube 5 by bolts 41 and fasteners 43, etc.

[0040] The bending plate 19 is composed of a bending plate body 49 and a folded portion 51. Before being installed on the telescopic bracket 17, the bending plate body 49 is formed in a flat shape. The bending plate body 49 is composed of a wide portion 53 with a large vertical dimension (width dimension) and a narrow portion 55 with a small vertical dimension (width dimension) of the vehicle body. The folded portion 51 is a slightly extended version of the wide portion 53, and the vertical dimension (width dimension) of the folded portion 51 is equal to the width dimension of the wide portion 53.

[0041] As shown in Figures 5 and 6, the telescopic bracket 17 is provided with a planar guide surface 57, a protrusion 59 projecting from the guide surface 57, and a contact surface 61.

[0042] The following describes the state in which the bending plate 19 is installed on the telescopic bracket 17 and the detachment plate 21, thereby forming the energy absorption mechanism 8.

[0043] The bending plate 19 has a folded portion 51 and a wide portion 53, which are located along its longitudinal direction, fixed to the release plate 21. More specifically, the wide portion 53 of the bending plate 19 is fixed to the release plate 21 by one of a pair of bolts 41. In addition, the folded portion 51 of the bending plate 19 is fixed to the release plate 21 by fitting into a groove in the release plate 21.

[0044] The width direction of the bending plate 19 is in the direction of the vehicle's vertical axis. When viewed in the direction of the vehicle's vertical axis, the elongated narrow section 55 of the bending plate 19 is bent in an arc shape (semi-arc shape) in the middle of this longitudinal direction. The part of the bending plate 19 excluding the middle of the narrow section 55 extends long in the front-to-rear direction of the vehicle, and its thickness direction is in the direction of the vehicle's width.

[0045] When viewed in the vertical direction of the vehicle body, the protrusion 59 has a curved (semi-circular) shape on one side, and the middle part of the narrow section 55 is curved in an arc shape as it contacts the curved part of the protrusion 59. The radius of the arc of the narrow section 55 is larger than the radius of the arc of the protrusion 59. The part of the narrow section 55 of the bending plate 19 that extends from the arc-shaped part on the opposite side from the wide section 53 contacts the planar contact surface 61 of the telescopic bracket 17.

[0046] One end of the bending plate 19 in the width direction is in contact with the planar guide surface 57 of the telescopic bracket 17. Furthermore, a gap 63 is formed between the portion of the narrow part 55 of the bending plate 19 that extends from the arc-shaped portion on the opposite side of the wide portion 53 and the convex portion 59. In other words, the convex portion 59 and the portion that extends from the arc-shaped portion on the opposite side of the wide portion 53 are separated from each other in the vehicle width direction.

[0047] A through hole (not shown) is formed in the first flat plate portion 35 of the bracket 29. The bracket 29 is then installed on the movable body 11 by fitting a part of the movable body 11 into the through hole.

[0048] Incidentally, the rigidity and strength of the bracket 29, the inner tube side member 15, and the telescopic bracket 17 are greater than those of the shear pin and the bending plate 19. Therefore, when a predetermined impact force is applied to the inner tube 5, the bracket 29, the inner tube side member 15, and the telescopic bracket 17 will not break but will only undergo slight elastic deformation.

[0049] Here, the rigidity of the bracket 29 may be reduced so that after a predetermined impact force is applied to the inner tube 5 and the shear pin breaks, both the bending plate 19 and the bracket 29 undergo plastic deformation. Even if the bracket 29 undergoes plastic deformation, it remains fixed to the telescopic mechanism 10 and the energy absorption mechanism 8.

[0050] As shown in Figure 1, the telescopic mechanism 10 comprises an electric motor (not shown), a screw shaft 71, and a screw nut 73. The telescopic mechanism 10 is also formed by an L-shaped drive mechanism bracket 75 that supports the screw shaft 71 and the screw nut 73 (movable body 11). The drive mechanism bracket 75 is fastened to the column housing 4 via fixing bolts (not shown). In this way, the housing 13 of the telescopic mechanism 10 is fixed to the column housing 4.

[0051] In the steering device 1, the inner tube 5 is moved in the longitudinal direction of the vehicle body by pushing and pulling it via a screw nut 73 and an energy absorption mechanism 8. This movement operation moves the steering wheel, which is connected to the rear end of the steering shaft 7, in the longitudinal direction of the vehicle body, thereby adjusting the telescopic position of the steering wheel.

[0052] The effects and advantages of this embodiment will be explained below.

[0053] (1) The steering device 1 comprises a column housing 4 supported by the vehicle body, an inner tube 5 provided to be axially movable relative to the column housing 4, and a drive unit (telescopic mechanism) 10 supported by the column housing 4 and driving the inner tube 5 in the axial direction. The steering device 1 is unitized and includes an energy absorption mechanism 8 provided between the inner tube 5 and the drive unit (telescopic mechanism) 10, with a first fixing part 25 fixed to the inner tube 5 and a second fixing part 27 fixed to the drive unit (telescopic mechanism) 10, configured to absorb impact forces applied to the inner tube 5. The steering device 1 includes a support part 80 for supporting the bracket (telescopic bracket 17) of the unitized energy absorption mechanism 8 on the column housing 4.

[0054] By forming the aforementioned support portion 80, when assembling the telescopic bracket 17 to the column housing 4, the telescopic bracket 17 can be slid from either the front-rear direction of the vehicle and engaged with the column housing 4 for assembly. This makes it easy to install the energy absorption mechanism 8 to the column housing 4 using the support portion 80. Furthermore, by forming the aforementioned support portion 80, this support portion 80 also functions as a guide for movement in the front-rear direction (axial direction) of the vehicle body during energy absorption, thus enabling stable energy absorption.

[0055] As described above, according to this embodiment, it is possible to provide a steering device 1 that can improve the ease of assembling the energy absorption mechanism 8 to the inner tube 5 and the drive unit (telescopic mechanism) 10 for moving the inner tube 5.

[0056] (2) In the steering device 1, the support portion 80 has a guide portion 81 formed to extend axially along the column housing 4, and a lower recess 87 formed on the bracket (telescopic bracket 17) of the energy absorption mechanism 8, which engages with the guide portion 81 from below and is formed to restrain the movement of the guide portion 81 in the vehicle width direction.

[0057] By forming the aforementioned support portion 80, when assembling the telescopic bracket 17 to the column housing 4, the telescopic bracket 17 can be slid from either the front-rear direction of the vehicle and engaged with the column housing 4 for assembly. This makes it easy to install the energy absorption mechanism 8 to the column housing 4 using the support portion 80 (guide portion 81, lower recess 87). Furthermore, by forming the aforementioned support portion 80, this support portion 80 (guide portion 81, lower recess 87) also functions as a guide against movement in the front-rear direction (axial direction) of the vehicle body during energy absorption, thus enabling stable energy absorption. In addition, since the movement of the guide portion 81 in the vehicle body width direction is restrained by the lower recess 87, it is possible to suppress the movement of the telescopic bracket 17 in the vehicle body width direction during energy absorption (when the engagement between the release plate 21 and the telescopic bracket 17 is released).

[0058] (3) In the steering device 1, the support portion 80 is formed on the bracket (telescopic bracket 17) of the energy absorption mechanism 8, is located above the lower recess 87, and has an upper projection 93 that engages with the guide portion 81 from above.

[0059] The support portion 80 further includes an upper projection 93, which allows the guide portion 81 to be sandwiched vertically by the lower recess 87 and the upper projection 93, enabling the telescopic bracket 17 to be slid into the column housing 4 from either the front or rear direction of the vehicle. This makes it easy to install the energy absorption mechanism 8 into the column housing 4 using the support portion 80 (guide portion 81, lower recess 87, and upper projection 93). Furthermore, when energy is absorbed (when the engagement between the release plate 21 and the telescopic bracket 17 is released), the upper projection 93 contacts the upper surface of the guide portion 81, preventing the telescopic bracket 17 from moving downward due to its own weight.

[0060] Although this embodiment has been described above, this embodiment is not limited to these, and various modifications are possible within the scope of the gist of this embodiment. [Explanation of Symbols]

[0061] 1. Steering system 4 Column Housing 5 Inner Tubes 8. Energy absorption mechanism 10. Drive unit (telescopic mechanism) 17 Drive unit side member (telescopic bracket) 25 First fixation site 27 Second fixation site 80 Support part 81 Guide section 83 First protrusion 85 Second protrusion 87 Lower recess 93 Upper projection

Claims

1. A column housing supported by the vehicle body, An inner tube is provided so as to be movable in the axial direction relative to the column housing, A drive unit supported by the column housing and driving the inner tube in the axial direction, An energy absorption mechanism is provided as a unit, located between the inner tube and the drive unit, with a first fixing portion fixed to the inner tube and a second fixing portion fixed to the drive unit, thereby absorbing the impact force applied to the inner tube. The system includes a support portion for supporting the bracket of the energy absorption mechanism, which is a unitized unit, on the column housing, Steering system.

2. The aforementioned support portion is A guide portion formed in the column housing so as to extend along the axial direction, The energy absorption mechanism is configured to have a lower recess formed in the bracket that engages with the guide portion from below, The steering device according to claim 1.

3. The steering device according to claim 2, wherein the support portion is formed on the bracket of the energy absorption mechanism, is located above the lower recess, and has an upper projection that engages with the guide portion from above.

Images