JP2008280002A - Impact absorbing steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impact absorbing steering device in which a sufficient impact absorbing stroke is secured. <P>SOLUTION: A steering column 12 retractable in the axial direction X1 comprises a lower tube 14 secured to a vehicle body side member through a first bracket 15 and an upper tube 13. The upper end of the lower tube 14 is fitted to the inner periphery of the lower end of the upper tube. The upper tube 13 is held by the lower tube 14 while the pair of leg parts 17, 17 of the first bracket 15 are fitted to the pair of axial grooves 19, 19. Since the first bracket 15 is not moved during the impact absorption, the axial movement of the upper tube 13 is not restricted due to the interference of the first bracket 15 with an electric motor 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an impact absorbing steering device used in a vehicle such as an automobile.

Some shock absorbing steering devices absorb the impact applied to the steering member from the driver during the secondary collision by relatively moving the upper tube and the lower tube fitted to each other in the axial direction (for example, , See Patent Document 1).
In the following Patent Document 1, the upper tube is fixed to the vehicle body side member by the support member, and when the vehicle collides, the support member releases the fixation between the upper tube and the vehicle body side member, and the support member becomes the upper tube. To move with.

As a support member capable of releasing the fixation between the upper tube and the vehicle body side member in the event of a vehicle collision, there is one including a breakable pin (for example, see Patent Document 2).
JP 2006-36080 A Japanese Patent Laying-Open No. 2005-14832 (FIGS. 7 and 8)

However, in the shock absorbing steering device described in Patent Document 1, since the support member moves along with the upper tube, the support member is attached to a member (for example, an electric motor or a housing) disposed below the upper tube in the axial direction. Interference may limit the amount of axial movement (impact absorption stroke) of the upper tube.
The present invention has been made based on such a background, and an object thereof is to provide an impact absorbing steering apparatus in which a sufficient impact absorbing stroke is ensured.

  In order to achieve the above object, the present invention provides a steering column (12) that rotatably supports a steering shaft (5) coupled to a steering member (2), and a steering column attached to a vehicle body side member (100). The steering column includes an upper tube (13) and a lower tube (14) that are fitted so as to be relatively movable in the axial direction (X1). It includes a leg (17) fixed to the inner tube as the lower tube through an axial groove (19) formed in the outer tube as a tube. When the shock is absorbed, the leg and the axial groove move relative to each other. The shock absorbing steering device (1, 1b) is characterized by being configured as described above.

  In order to achieve the above object, the present invention includes a steering column (12) that rotatably supports a steering shaft coupled to a steering member, and a support member that is attached to a vehicle body side member (100) and supports the steering column. (15), and the steering column includes an upper tube (113) and a lower tube (114) that are fitted so as to be relatively movable in the axial direction, and the support member is fixed to an outer tube as a lower tube And a leg portion (17) that engages with an axial groove (19) formed in the inner tube as an upper tube through an insertion hole (27) formed in the outer tube. The shock absorbing steering device (1a) is characterized in that the portion and the axial groove move relative to each other.

According to these inventions, since the support member is fixed to the lower tube that is prevented from moving at the time of shock absorption, the support member interferes with other members at the time of shock absorption, and the shock absorption stroke is increased. There is no limit. Therefore, a sufficient shock absorbing stroke can be ensured.
In addition, as a support member, it is not necessary to use a support member having a complicated structure that can release the fixation between the lower tube and the vehicle body side member in the event of a vehicle collision, so that the number of parts and the cost can be reduced. it can. That is, it is not necessary to use a support member having a complicated structure such as a support member including the breakable pin.

Furthermore, since the upper tube is guided in the axial direction of the steering column by the axial groove formed in the upper tube and the leg portion of the support member, the upper tube can be reliably moved in the axial direction with respect to the lower tube. it can.
Furthermore, a sufficient shock absorbing stroke can be ensured regardless of whether the lower tube is an outer tube or an inner tube.

  Further, the groove width (W1) of the axial groove is gradually reduced as the leg moves in the direction of movement with respect to the axial groove when absorbing the shock, and the relative movement of the leg and the axial groove is reduced. In some cases, the shock is absorbed. In this case, when the leg portion and the axial groove move relative to each other, the groove width of the axial groove is gradually expanded by the leg portion, and resistance due to relative movement between the leg portion and the axial groove is applied to the upper tube. Thus, it is possible to reliably absorb the shock when absorbing the shock.

  The shock absorbing steering device includes an electric motor (4) for assisting steering, and the electric motor includes an annular rotor (21) and an annular stator (22) arranged concentrically with the steering shaft, and these A cylindrical motor housing (23) that houses the rotor and stator and is connected to the lower end (14a) of the lower tube. In this case, since the support member is fixed to the lower tube, the support member does not interfere with the motor housing disposed below the upper tube in the axial direction during impact absorption. Therefore, a sufficient shock absorbing stroke can be ensured.

  In the above description, the alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a schematic external view of an electric power steering apparatus 1 according to an embodiment of the present invention. FIG. 2 is a schematic partial sectional view showing a schematic configuration of the electric power steering apparatus 1. FIG. 3 is a schematic plan view of a part of the electric power steering apparatus 1 as viewed from the direction of arrow III in FIG.

  Referring to FIGS. 1 and 2, an electric power steering device 1 serving as an impact absorbing steering device rotates a steered wheel (not shown) in conjunction with a steering member 2 such as a steering wheel and the steering of the steering member 2. A steering mechanism 3 for steering and an electric motor 4 for assisting steering are provided. As the steering mechanism 3, for example, a rack and pinion mechanism is used.

  The steering member 2 and the steering mechanism 3 are mechanically connected via a steering shaft 5, an intermediate shaft 6, and the like. Steering (rotation) of the steering member 2 is transmitted to the steering mechanism 3 via the steering shaft 5, the intermediate shaft 6, and the like. Further, the rotation transmitted to the steering mechanism 3 is converted into an axial movement of a rack shaft (not shown). Thereby, a steered wheel is steered.

The steering shaft 5 extends linearly. The electric motor 4 is coaxially connected to the steering shaft 5. Hereinafter, the steering member 2 side along the axial direction X1 of the steering shaft 5 is referred to as an upper side, and the steering mechanism 3 side is referred to as a lower side.
The steering shaft 5 includes an input shaft 7 and an output shaft 8. Each of the input shaft 7 and the output shaft 8 is a cylindrical member extending linearly. The input shaft 7 and the output shaft 8 are coaxially arranged. Further, the upper end portion of the output shaft 8 is serrated and fitted, for example, to the inner periphery of the lower end portion of the input shaft 7. The input shaft 7 and the output shaft 8 are coupled so as to be able to rotate together around the center axis of each other and to be relatively movable in the axial direction X1 of the steering shaft 5.

  The steering member 2 is coupled to the upper end portion of the input shaft 7 so as to be able to rotate together. The steering mechanism 3 is connected to the lower end portion of the output shaft 8 via the intermediate shaft 6. Specifically, a yoke 9 is fixed to the lower end portion of the output shaft 8, and one end of the intermediate shaft 6 is connected to the yoke 9. The yoke 9 includes a connecting portion 10 having, for example, a U-shaped cross section connected to one end of the intermediate shaft 6, and a fitting portion 11 into which the lower end portion of the output shaft 8 is fitted. For example, the lower end portion of the output shaft 8 is serrated to the fitting portion 11.

In FIG. 2, the output shaft 8 is illustrated as a single member, but the present invention is not limited to this, and the output shaft 8 may be configured by a plurality of shafts.
The steering shaft 5 is inserted through the inner periphery of the cylindrical steering column 12. The steering shaft 5 is rotatably supported by the steering column 12. The steering column 12 includes a cylindrical upper tube 13 and a lower tube 14 that are fitted to each other. Each of the upper tube 13 and the lower tube 14 extends linearly. The upper tube 13 and the lower tube 14 are coaxially arranged.

  The upper tube 13 and the lower tube 14 are coupled so as to be relatively movable in the axial direction of the steering column 12 (the same direction as the axial direction X1 in FIGS. 1 and 2). Specifically, the upper end portion of the lower tube 14 is fitted to the inner periphery of the lower end portion of the upper tube 13. That is, in this embodiment, the lower tube 14 is an inner tube, and the upper tube 13 is an outer tube.

  In the fitting portion between the upper tube 13 and the lower tube 14, the inner peripheral surface of the upper tube 13 and the outer peripheral surface of the lower tube 14 are in frictional engagement, for example. Accordingly, when the upper tube 13 and the lower tube 14 are relatively moved in the axial direction X1, resistance is applied to one or both of the upper tube 13 and the lower tube 14.

  The steering column 12 is fixed to the vehicle body side member 100 via a first bracket 15 as a support member. The first bracket 15 is fixed to the vehicle body side member 100 by, for example, fixing bolts. The first bracket 15 includes a plate-like fixing portion 16 fixed to the vehicle body side member 100 and a pair of plate-like leg portions 17 and 17 connected to the fixing portion 16. The pair of leg portions 17 and 17 extend along the axial direction X1 and face each other in parallel with a gap therebetween. One end of each leg portion 17 is fixed to the outer peripheral surface of the lower tube 14. That is, the lower tube 14 is fixed to the vehicle body side member 100 by the first bracket 15, and the upper tube 13 is held by the lower tube 14 fixed to the vehicle body side member 100. Each leg portion 17 has a predetermined thickness in a direction orthogonal to the axial direction X1.

  The upper tube 13 rotatably supports the input shaft 7 via a bearing 18. The input shaft 7 and the upper tube 13 are connected via a bearing 18 so as to be able to move in the axial direction X1. For example, when a load of a predetermined value or more is applied to the upper tube 13 during a vehicle collision, the input shaft 7 and the upper tube 13 move together with the steering member 2 downward in the axial direction X1. At this time, the upper tube 13 moves downward in the axial direction X1 with respect to the lower tube 14, and resistance in the direction opposite to the moving direction is applied from the lower tube 14 to the upper tube 13.

  With reference to FIGS. 1 to 3, the upper tube 13 is formed with a pair of slit-shaped axial grooves 19, 19 extending from the lower end thereof upward in the axial direction X <b> 1. The axial length of each axial groove 19 is longer than the maximum amount of movement of the upper tube 13 relative to the lower tube 14 in the axial direction X1. Further, as shown in FIG. 3, the groove width W1 of each axial groove 19 is gradually reduced toward the upper side in the axial direction X1. That is, each axial groove 19 tapers as it goes upward in the axial direction X1. The groove width W <b> 1 at the lower end in the axial direction of each axial groove 19 is slightly smaller than the thickness of the leg portion 17.

  The upper tube 13 is connected to the lower tube 14 with the pair of leg portions 17 and 17 fitted in the pair of axial grooves 19 and 19, respectively. As described above, since the groove width W1 at the lower end in the axial direction of each axial groove 19 is slightly smaller than the thickness of the leg portion 17, each leg portion 17 is sandwiched between the upper tubes 13, The upper tube 13 is engaged. The upper tube 13 is held by the first bracket 15 by a pair of opposing surfaces 20 (see FIG. 3) defining each axial groove 19 engaging the corresponding leg portion 17. That is, the upper tube 13 is held by the first bracket 15 so as to be caught by the pair of leg portions 17 and 17. The upper tube 13 is held by the first bracket 15 and the lower tube 14.

In addition, since the pair of leg portions 17 and 17 are fitted in the pair of axial grooves 19 and 19, respectively, the upper tube 13 can be reliably moved in the axial direction X1. That is, the upper tube 13 is guided in the axial direction X1 by the relative movement of the pair of leg portions 17 and 17 and the pair of axial grooves 19 and 19 in the axial direction X1.
Referring to FIG. 2, the electric motor 4 includes an annular rotor 21 that coaxially surrounds the output shaft 8, an annular stator 22 that coaxially surrounds the rotor 21, and a cylindrical shape that houses the rotor 21 and the stator 22. Motor housing 23. The rotor 21 is coupled to the output shaft 8 so as to be able to rotate together. The output torque of the electric motor 4 as a steering assist force is directly transmitted to the output shaft 8.

  Further, the outer diameter of the motor housing 23 is made larger than the outer diameter of the upper tube 13. The motor housing 23 has an upper end wall 24 fixed to the lower end 14 a of the lower tube 14. The motor housing 23 is coaxial with the lower tube 14. A second bracket 26 fixed to the vehicle body side member 100 is fixed to the lower end wall 25 of the motor housing 23. The electric motor 4 is fixed to the vehicle body side member 100 by the second bracket 26. The second bracket 26 is fixed to each of the vehicle body side member 100 and the motor housing 23 by fixing bolts, for example.

FIG. 4 is a diagram for explaining the state of the electric power steering apparatus 1 before and after a vehicle collision. FIG. 5 is a plan view of the upper tube 13 showing a state in which the pair of leg portions 17 and 17 and the pair of axial grooves 19 and 19 are relatively moved in the axial direction X1 due to a vehicle collision.
Referring to FIGS. 2, 4 and 5, when the vehicle does not collide normally, as shown in FIG. 4A, the steering member 2 is held at a substantially fixed position in the axial direction X1. Yes. From this state, when the vehicle collides (primary collision) and the driver collides with the steering member 2 (secondary collision), an impact is applied to the steering member 2 from the driver. The impact applied to the steering member 2 is transmitted to the upper tube 13 via the input shaft 7 and the bearing 18.

When the magnitude of the impact applied to the upper tube 13 exceeds the holding force of the upper tube 13 by the lower tube 14 and the first bracket 15, the upper tube 13 is moved together with the steering member 2, the input shaft 7 and the like in the axial direction X1. Move down.
At this time, the upper tube 13 moves downward in the axial direction X <b> 1 with respect to the lower tube 14, and resistance (impact absorption load) in the direction opposite to the moving direction is applied from the lower tube 14 to the upper tube 13. Further, when the upper tube 13 moves downward in the axial direction X1 with respect to the lower tube 14, as shown in FIG. 5, the pair of leg portions 17 and 17 and the pair of axial grooves 19 and 19 are relative to each other in the axial direction X1. While moving, the groove width W1 of each axial groove 19 is gradually pushed and expanded by the corresponding leg portion 17, and the resistance (shock absorbing load) in the direction opposite to the moving direction is applied from the first bracket 15 to the upper tube 13. Added. That is, resistance due to friction between each leg 17 and the upper tube 13 and resistance due to deformation of the upper tube 13 are applied to the upper tube 13 as an impact absorbing load.

The impact due to the secondary collision is absorbed by the impact absorbing load applied to the upper tube 13 from the lower tube 14 and the first bracket 15. As a result, the reaction force applied to the driver from the steering member 2 when the driver collides with the steering member 2 is reduced, and the safety of the driver is enhanced.
The steering member 2, the input shaft 7, the upper tube 13 and the like move until the lower end of the upper tube 13 comes into contact with the upper end wall 24 of the motor housing 23, as shown in FIG. At this time, the fixing of the lower tube 14 and the vehicle body side member 100 by the first bracket 15 is not released unless the first bracket 15 is damaged by the impact of the collision of the vehicle. Further, the relative positions of the lower tube 14, the first bracket 15, and the electric motor 4 are not changed unless the members 4, 14, and 15 are deformed or damaged by an impact caused by a vehicle collision. . That is, the first bracket 15 does not interfere with the motor housing 23 and the axial movement of the upper tube 13 is not restricted.

  As described above, in the present embodiment, since the first bracket 15 as the support member is fixed to the lower tube 14 that does not move at the time of shock absorption, the first bracket 15 is attached to the upper tube at the time of shock absorption. The shock absorbing stroke (the amount of movement of the upper tube 13 in the axial direction) is not limited by interfering with other members (such as the motor housing 23) disposed below the 13 axial directions X1. Therefore, a sufficient shock absorbing stroke can be ensured. As a result, the impact applied to the steering member 2 by the secondary collision can be reliably absorbed, and the driver's safety can be improved.

  In addition, the first bracket 15 does not have to have a complicated structure capable of releasing the fixation between the lower tube 14 and the vehicle body side member 100 in the event of a vehicle collision, so that the number of parts and the cost can be reduced. Can be planned. Specifically, the number of parts constituting the first bracket 15 can be reduced, or the first bracket 15 can be downsized. Further, there are two shock absorbing loads for absorbing the impact caused by the secondary collision (the fitting portion between the upper tube 13 and the lower tube 14 and the engaging portion between the pair of leg portions 17 and 17 and the upper tube 13). Therefore, the impact can be absorbed more reliably.

FIG. 6 is a schematic partial sectional view showing a schematic configuration of an electric power steering apparatus 1a according to another embodiment of the present invention. In FIG. 6, the same components as those shown in FIG. 2 described above are denoted by the same reference numerals as those in FIG.
Referring to FIG. 6, the embodiment shown in FIG. 6 is mainly different from the above-described embodiment in that the upper tube 113 is an inner tube and the lower tube 114 is an outer tube. It is in. Further, each leg portion 17 of the first bracket 15 is fixed to the lower tube 114 in a state of being inserted through the insertion hole 27 formed in the lower tube 114, and protrudes to the inner peripheral side of the lower tube 114. A part of the leg 17 is fitted in the axial groove 19. Each leg portion 17 is fixed to the lower tube 114 by, for example, welding, adhesion, press fitting, fastening using a bolt or the like.

  In the present embodiment, as in the above-described embodiment, the impact at the time of the secondary collision is absorbed by the impact absorbing load generated when the upper tube 113 and the like move downward in the axial direction X1 with respect to the lower tube 114. It has become so. Further, since the first bracket 15 is fixed to the lower tube 114 that does not move when absorbing the impact, the first bracket 15 interferes with the motor housing 23 and the like, and the axial movement of the upper tube 113 is restricted. It will never be done. That is, in the present invention, even if the lower tube 114 is an outer tube, a sufficient shock absorbing stroke can be secured.

FIG. 7 is an illustrative external view of an electric power steering apparatus 1b according to still another embodiment of the present invention. In FIG. 7, the same components as those shown in FIG. 1 described above are denoted by the same reference numerals as those in FIG.
Referring to FIG. 7, the embodiment shown in FIG. 7 is mainly different from the embodiment shown in FIG. 1 in that the output shaft 8 and the yoke 109 are integrated into a single part. There is to be. The yoke 109 includes the connecting portion 10.

The integrated product of the output shaft 8 and the yoke 109 may be integrally formed with a single member, or may be integrated with another member. When other members are integrated, the individual members can be fixed and integrated with each other, for example, by welding, adhesion, press-fitting, or the like.
In this embodiment, since the fitting part 11 of the yoke 9 shown in FIG. 1 is not provided, the electric power steering device 1b is downsized. Further, since the output shaft 8 and the yoke 109 are integrated into a single component, the output shaft 8 and the yoke 109 need not be assembled when the electric power steering apparatus 1b is assembled. That is, the assembly man-hour of the electric power steering device 1b is reduced.

  The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims. For example, in the above-described embodiment, the example in which the present invention is applied to the electric power steering devices 1, 1 a, 1 b not including the speed reduction mechanism such as the worm gear has been described, but the present invention is applied to the electric power steering device including the speed reduction mechanism. May be applied. Further, the shock absorbing steering device is not limited to the electric power steering device, but may be other steering devices.

1 is an illustrative external view of an electric power steering apparatus according to an embodiment of the present invention. It is an illustration partial sectional view showing a schematic structure of the above-mentioned electric power steering device. FIG. 3 is a schematic plan view of a part of the electric power steering device as viewed from the direction of arrow III in FIG. 1. It is a figure for demonstrating the state of the electric power steering apparatus before and behind the collision of a vehicle. It is a top view of the upper tube which shows the state which a pair of leg part and a pair of axial groove | channel moved relatively to the axial direction by the collision of the vehicle. It is an illustration partial sectional view showing a schematic structure of an electric power steering device concerning other embodiments of the present invention. FIG. 10 is an illustrative external view of an electric power steering apparatus according to still another embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Electric power steering device (impact absorption steering device), 2 ... Steering member, 4 ... Electric motor, 5 ... Steering shaft (steering shaft), 12 ... Steering column , 13 ... Upper tube, 14 ... Lower tube, 14a ... Lower end of the lower tube, 15 ... First bracket (support member), 17 ... Leg part, 19 ... Axial direction Groove, 21 ... rotor, 22 ... stator, 23 ... motor housing, 27 ... insertion hole, 100 ... vehicle body side member, 113 ... upper tube, 114 ... lower tube, W1 ... groove width, X1 ... axial direction

Claims (4)

A steering column that rotatably supports a steering shaft coupled to the steering member;
A support member attached to the vehicle body side member and supporting the steering column,
The steering column includes an upper tube and a lower tube that are fitted to be axially movable relative to each other.
The support member includes a leg portion fixed to an inner tube as a lower tube through an axial groove formed in an outer tube as an upper tube,
An impact-absorbing steering apparatus, wherein the leg portion and the axial groove move relative to each other when absorbing the impact. A steering column that rotatably supports a steering shaft coupled to the steering member;
A support member attached to the vehicle body side member and supporting the steering column,
The steering column includes an upper tube and a lower tube that are fitted to be axially movable relative to each other.
The support member includes a leg portion that is fixed to the outer tube as the lower tube and engages with an axial groove formed in the inner tube as the upper tube through an insertion hole formed in the outer tube.
An impact-absorbing steering apparatus, wherein the leg portion and the axial groove move relative to each other when absorbing the impact.   3. The groove width of the axial groove according to claim 1 or 2, wherein the width of the axial groove is gradually reduced as the leg moves in the direction of movement with respect to the axial groove when absorbing the shock. An impact-absorbing steering apparatus characterized in that an impact is absorbed with movement. In any one of Claims 1-3, The electric motor for steering assistance is provided,
The electric motor includes an annular rotor and an annular stator arranged concentrically with the steering shaft, and a cylindrical motor housing that houses the rotor and the stator and is connected to the lower end of the lower tube. A shock-absorbing steering device.

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