Energy absorbing strip integrated with telescopic drive bracket

Abstract

The invention relates to an energy absorbing strip integrated with a telescopic drive bracket. A steering column assembly includes a lower jacket. The steering column assembly also includes an upper jacket disposed within the lower jacket and adjustable in a retractable manner relative to the lower jacket. The steering column assembly also includes a telescopic drive assembly that electrically moves a telescopic drive nut in an axial direction to adjust the upper jacket in a telescopic manner. The steering column assembly also includes an energy absorbing strip coupled directly to the upper jacket and directly to the telescoping drive nut to transfer axial movement of the telescoping drive nut to the upper jacket.

Description

Technical Field

[0001] The following description relates to an energy absorbing device for a steering column, and more particularly, to an energy absorbing strap integrated with a telescoping drive bracket for a steering column assembly. Background Art

[0002] Vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable vehicles) include various steering system solutions (e.g., steer-by-wire and driver interface steering). These steering system solutions typically include a steering column assembly for converting steering inputs into outputs that interact with steering linkages to ultimately cause the vehicle wheels to turn. The steering column typically includes various safety features, such as air bags for reducing impact forces. In addition, many steering column assemblies are collapsible and include one or more energy absorbing features (such as energy absorbing strips). Some energy absorbing strips are configured to roll along the length of the energy absorbing strip to absorb energy and are typically referred to as rolling strips. Typically, rolling strips absorb energy during the deformation of the strip in an impact event, where the kinetic energy can be dissipated by compression of the steering column assembly.

[0003] In a power telescopic (i.e., translational) steering column, a drive bracket is used to connect a telescopic actuator to an upper housing to perform telescopic movement of the upper housing relative to a lower housing. The energy absorbing function is achieved by the above-mentioned energy absorbing strip, which is a separate component housed within the drive bracket. The drive bracket is frangibly connected to the upper housing to release under a specified load to allow the energy absorbing strip to engage and become a load path. Typically, a set of connecting parts are included in the entire assembly of the telescopic drive bracket and the energy absorbing strip assembly. The number of parts and the associated assembly steps increase the cost and assembly complexity of the entire system. Summary of the invention

[0004] According to one aspect of the present disclosure, a steering column assembly includes a lower jacket. The steering column assembly also includes an upper jacket, which is disposed within the lower jacket and can be adjusted in a telescopic manner relative to the lower jacket. The steering column assembly also includes a telescopic drive assembly, which electrically moves a telescopic drive nut in an axial direction to adjust the upper jacket in a telescopic manner. The steering column assembly also includes an energy absorbing strip, which is directly coupled to the upper jacket and directly coupled to the telescopic drive nut to transmit axial movement of the telescopic drive nut to the upper jacket.

[0005] According to another aspect of the present disclosure, an energy absorbing strip for a vehicle steering column includes a radially outer leg, the radially outer leg including a first radially extending flange and a second radially extending flange. The energy absorbing strip also includes a center leg. The energy absorbing strip also includes a radially inner leg. The energy absorbing strip also includes a first curved section connecting the radially outer leg and the center leg. The energy absorbing strip also includes a second curved section connecting the center leg and the radially inner leg.

[0006] According to yet another aspect of the present disclosure, a method of assembling an energy absorbing strip to a steering column is provided. The method includes orienting the energy absorbing strip perpendicular to a longitudinal axis of the steering column. The method also includes positioning a locking tab within an hourglass-shaped aperture defined by an upper jacket of the steering column. The method also includes rotating the energy absorbing strip 90 degrees to orient the energy absorbing strip parallel to the longitudinal axis of the steering column.

[0007] These and other aspects of the present disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be emphasized that, in accordance with conventional practice, the various features of the drawings are not drawn to scale. Instead, the sizes of the various features are arbitrarily enlarged or reduced for clarity.

[0009] Figure 1 A vehicle having a steering system is schematically shown;

[0010] Figure 2 is a perspective view of a portion of a steering column having a powered telescoping assembly and an energy absorbing strip having a telescoping drive bracket integrally formed therein;

[0011] Figure 3 A first condition is shown with the energy absorbing strip and powered telescoping assembly partially disassembled;

[0012] Figure 4 showing a second condition in which the energy absorbing strip and powered telescoping assembly are partially disassembled;

[0013] Figures 5 to 10 The assembly sequence of the energy absorbing strip to the upper jacket and to the telescopic drive nut is shown;

[0014] Fig.11 is a perspective view of a portion of an energy absorbing strip disposed within a tunnel defined by a lower jacket, with an upper section of the energy absorbing strip removed for clarity;

[0015] Fig.12 is a perspective view of a portion of an energy absorbing strip illustrating the upper jacket anti-roll physical properties; and

[0016] Fig.13 is a front view of an energy absorbing strip illustrating the anti-liftoff physical properties of the strip. DETAILED DESCRIPTION

[0017] The following discussion is directed to various embodiments of the present disclosure. Although one or more of these embodiments may be described in more detail than other embodiments, the disclosed embodiments should not be interpreted or otherwise used to limit the scope of the present disclosure (including the claims). In addition, it will be understood by those skilled in the art that the following description has a wide range of applications, and the discussion of any embodiment is only meant to illustrate the embodiment, and is not intended to imply that the scope of the present disclosure (including the claims) is limited to the embodiment.

[0018] As described, vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, RVs, or other suitable vehicles) include various steering systems (e.g., steer-by-wire and driver interface steering). These steering systems typically include a steering column assembly for converting steering inputs into outputs that interact with steering linkages to ultimately cause the vehicle wheels to turn. The steering column includes various safety features, such as air bags for reducing impact forces. In addition, many steering columns are collapsible and include one or more energy absorbing features (such as energy absorbing strips) that allow for a specific amount of compression.

[0019] See first Figure 1 , a vehicle 20 is generally shown according to the principles of the present disclosure. The vehicle 20 may include any suitable vehicle, such as a car, a truck, a sport utility vehicle, a minivan, a crossover, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. Although the vehicle 20 may be a passenger vehicle having wheels and for use on roads, the principles of the present disclosure may be applied to other vehicles, such as an airplane, a tractor, a boat, or other suitable vehicles. The vehicle 20 may include a propulsion system 30, such as an ignition system, an electronic system, or a combination thereof.

[0020] In some embodiments, the vehicle 20 may also include a steering system 40. The steering system 40 may be configured as a driver interface steering system, an autonomous driving system, or a system that allows both driver interface and autonomous steering. The steering system may include an input device 42 (such as a steering wheel), wherein the driver may mechanically provide steering input by turning the steering wheel. The steering column assembly 44 may include a steering column 45 extending from the input device 42 to an output assembly 46 along a longitudinal axis A. The output assembly 46 may include a pinion shaft assembly, an I-shaft, a universal joint, a wire control steering component, or any other feature conventionally positioned relative to the input device 42.

[0021] The steering column 45 can include at least two axially adjustable portions, for example, an upper jacket 48 and a lower jacket 50 that can be axially adjusted relative to each other. During an impact or other compressive force, the upper jacket 48 and the lower jacket 50 are allowed to move axially relative to each other. The relative axial movement is described herein as telescoping, wherein the upper jacket 48 telescopes within the lower jacket 50 within a range of axial positions from an extended column position to a retracted column position. The steering column assembly 44 can include additional portions that provide rake and / or tilt movement.

[0022] The energy absorbing device 52 is coupled to the upper jacket 48 to provide a variable stroke load absorbing arrangement. During a folding event, forces may cause the upper jacket 48 to move or fold along the longitudinal axis A of the steering column 45, and the energy absorbing device 52 dissipates at least some of the kinetic energy of the upper jacket (first jacket) 48 and the lower jacket (second jacket) 50 as they fold. Details of the energy absorbing device 52 are described herein.

[0023] The steering gear assembly 54 can be connected to the output assembly 46 via a steering gear input shaft 56. The steering gear assembly 54 can be configured as a rack and pinion, a (re)circulating ball steering gear, or any other type of steering gear associated with autonomous steering systems and driver interface steering systems. The steering gear assembly 54 can then be connected to the drive axle 58 via an output shaft 60. The output shaft 60 can include a pitman arm and a sector gear or other conventional components. The output shaft 60 is operably connected to the steering gear assembly 54 so that rotation of the steering gear input shaft 56 causes responsive movement of the output shaft 60 and causes the drive axle to rotate the wheel 61.

[0024] Figure 2A portion of a steering column 45, an energy absorbing device 52, and a telescoping drive assembly 100 are shown. The telescoping drive assembly 100 is a powered actuator that actuates telescopic movement of the upper sheath 48 relative to the lower sheath 50. The telescoping drive assembly 100 includes an electric actuator 102 (such as an electric motor) that drives rotational movement of a threaded rod 104. A gearbox 106 can facilitate the transfer of power from an output shaft (not shown) of the electric actuator 102 to the threaded rod 104. The rotation of the threaded rod 104 causes translation of a telescoping drive nut 108 that is threadedly connected to the outer surface of the threaded rod 104. The translation of the telescoping drive nut 108 is generally parallel to the longitudinal axis A of the steering column 45.

[0025] The energy absorbing device 52 includes an energy absorbing strip 110 (EA strip 110) that is directly coupled to the upper jacket 48. As described herein, the telescoping drive nut 108 is directly coupled to the EA strip 110. Unlike existing steering systems, the embodiments disclosed herein do not require what is commonly referred to as a telescoping drive bracket. Additionally, several coupling connection components (such as rivets, brackets, and welded plates) are not required in the embodiments disclosed herein, thereby reducing system cost and assembly complexity.

[0026] See now Figure 3 and Figure 4 , the EA strap 110 is shown assembled to the upper sheath 48 using the anti-lift fastener 112, but still removed from the telescoping drive nut 108. As shown, the upper sheath 48 is axially telescoping with the lower sheath 50, and once moved to the assembled position ( Figure 3 ), a portion of the EA strap 110 remains radially outside of the lower jacket 50, wherein the fastener 114 can be inserted through a pair of holes 116 defined by the radially outer legs 118 of the EA strap 110 and through a hole 120 defined by the telescoping drive nut 108. Figure 3 As shown, the radially outer leg 118 of the EA strap 110 includes a first radially extending flange 122 and a second radially extending flange 124. The space defined between the first radially extending flange 122 and the second radially extending flange 124 of the radially outer leg 118 is sufficient to seat a portion of the telescopic drive nut 108 therein. The telescopic drive nut 108 is positioned to align the hole 120 of the telescopic drive nut 108 with the pair of holes 116 of the radially outer leg 118 of the EA strap 110 for inserting the fastener 114 to directly couple the telescopic drive nut 108 to the EA strap 110. The direct coupling of the telescopic drive nut 108 to the EA strap 110 in combination with the direct coupling of the EA strap 110 to the upper sheath 48 enables the radially outer leg 118 of the EA strap 110 to function as a telescopic drive bracket, because axial movement of the telescopic drive nut 108 along the threaded rod 104 directly actuates telescopic movement of the upper sheath 48 relative to the lower sheath 50.

[0027] See now Figure 5 , the EA strap 110 includes a radially outer leg 118, a center leg 130, and a radially inner leg 132. The radially outer leg 118 is connected to the center leg 130 by a first curved section 134. The radially inner leg 132 is connected to the center leg 130 by a second curved section 136. Therefore, the EA strap 110 is generally S-shaped. The EA strap 110 extends from a first terminal 138, which is an end of the radially outer leg 118, to a second terminal 140, which is an end of the radially inner leg 132. As described above, the pair of holes 116 defined by the first radially extending flange 122 and the second radially extending flange 124 are located proximate to the first terminal 138 of the EA strap 110. The EA strap 110 includes a locking tab 150 proximate to the second terminal 140 of the EA strap 110. The locking tab 150 includes a stem 152 extending radially inward (i.e., toward the longitudinal axis A) from the radially inner leg 132. The locking tab 150 also includes a head section 154 extending radially inwardly from the stem 152. The head section 154 has a greater width than the stem 152 to form a generally T-shaped structure.

[0028] Figures 5 to 10 48. To assemble the EA strap 110 to the upper jacket 48, the longitudinal direction of the EA strap is initially oriented substantially perpendicular to the longitudinal axis A of the steering column 45, with the locking tabs 150 aligned with the apertures 156 defined by the upper jacket 48 ( Figure 5 ). The aperture 156 is generally "hourglass" shaped. Based on the shape of the locking tab 150 and the aperture 156, the head section 154 of the locking tab 150 can be fully inserted through the aperture 156 while the EA strap 110 is still oriented perpendicular to the longitudinal axis A of the steering column 45 ( Figure 6 ). The EA strip 110 is then rotated 90 degrees to orient the EA strip 110 substantially parallel to the longitudinal axis A of the steering column 45 ( Figure 7 In this orientation, the handle 152 of the locking tab 150 is in close contact with the inner wall of the hourglass orifice 156 ( Figure 8 The anti-lift fastener 112 is aligned with an energy absorption slot 158 ​​defined by the center leg 130 of the EA strap 110 near the first curved section 134 ( Fig. 9 ) and then fixed to the center leg 130 ( Fig.10). The locking tab 150 and the anti-lift fastener 112 couple the EA strap 110 directly to the upper jacket 48. The energy absorbing slot 158 ​​and the center leg 130 are shaped to allow the head of the anti-lift fastener 112 to be positioned below the plane of the center leg 130 to allow the head of the anti-lift fastener 112 to pass freely under the center leg 130 during the folding function of the EA strap 110.

[0029] See now Fig.11 , which transparently shows a portion of the lower jacket 50 to show the tunnel 160 defined by the radially outer surface of the upper jacket 48 and the lower jacket 50. In the fully assembled position, the center leg 130 and the radially inner leg 132 of the EA strap 110 are at least partially positioned within the tunnel 160. The radially inner leg 132 of the EA strap 110 includes a pair of anti-roll tabs 162 extending outwardly from the radially inner leg 132, also shown in FIG. Figure 5 The anti-roll tab 162 is sized to contact the interior lower jacket wall 164 of the tunnel 160 to prevent rolling of the upper jacket 48 relative to the lower jacket 50. The anti-roll tab 162 is resilient to compensate for manufacturing dimensional variations.

[0030] Fig.12 The physical characteristics associated with the anti-roll measures provided by the embodiments disclosed herein are shown. Specifically, the applied rolling load F from the upper jacket 48 and the resulting yaw torque T are shown. However, the anti-roll tab 162 provides a reaction load L. The reaction load L provided by the anti-roll tab 162 combined with the yaw reaction force C provided by the anti-lift fastener 112 balances the problems associated with the upper jacket rolling.

[0031] Fig.13 The physical characteristics associated with the anti-lift measures provided by the embodiments disclosed herein are shown. Specifically, during telescopic adjustment of the upper sheath 48, a force T substantially parallel to the longitudinal axis A of the steering column 45 is generated, which forces the end of the EA strap 110 upward. However, the anti-lift fastener 112 balances this force.

[0032] The embodiments disclosed herein advantageously reduce the cost and assembly complexity of the overall steering system.

[0033] Although the present invention has been described in detail in conjunction with only a limited number of embodiments, it is readily understood that the present invention is not limited to these disclosed embodiments. On the contrary, the present invention may be modified to include any number of changes, modifications, permutations, or equivalent arrangements that have not been described before but are commensurate with the spirit and scope of the present invention. In addition, although various embodiments of the present invention have been described, it should be understood that various aspects of the present invention may include only some of the described embodiments. In addition, any feature, element, component, or advantage of any one embodiment may be used in any other embodiment. Therefore, the present invention should not be considered to be limited by the foregoing description.

Claims

1. A steering column assembly, comprising: Lower sheath; an upper sheath disposed within the lower sheath and telescopically adjustable relative to the lower sheath; a telescopic drive assembly that electrically moves the telescopic drive nut in an axial direction to telescopically adjust the upper sleeve; and An energy absorbing strap is directly coupled to the upper sleeve and directly coupled to the telescoping drive nut to transfer axial movement of the telescoping drive nut to the upper sleeve.

2. The steering column assembly of claim 1 , wherein the energy absorbing strip comprises: radially outer legs; center leg; radial inner legs; a first curved section connecting the radially outer leg and the central leg; and A second curved section connects the center leg and the radially inner leg. 3 . The steering column assembly of claim 2 , wherein the radially outer surface of the upper jacket defines a tunnel with the lower jacket, wherein a portion of the energy absorbing strip is at least partially disposed within the tunnel.

4. The steering column assembly of claim 3, wherein the central leg and the radially inner leg are disposed within the tunnel, and wherein the radially outer leg is disposed radially outside of the tunnel. 5 . The steering column assembly of claim 4 , further comprising a pair of anti-roll tabs extending from the radially inner leg to contact an inner wall of the tunnel.

6. The steering column assembly of claim 2, wherein the energy absorbing strip is coupled to the upper jacket using an anti-lift fastener positioned within a slot defined by the center leg proximate the first curved section.

7. The steering column assembly of claim 2, wherein the energy absorbing strip is coupled to the upper jacket with a locking tab extending from the radially inner leg and into an aperture defined by the upper jacket.

8. The steering column assembly of claim 7, wherein the locking tab includes a stem and a head section.

9. The steering column assembly of claim 7, wherein the aperture defined by the upper jacket has an hourglass shape.

10. The steering column assembly of claim 2, wherein the radially outer leg includes a pair of radially extending flanges, each of the pair of radially extending flanges defining a respective hole, wherein a telescoping drive bracket defines a hole aligned with the hole defined by the radially extending flanges, wherein a fastener extends through the hole of the radially extending flange and the hole of the telescoping drive bracket to couple the telescoping drive bracket to the energy absorbing strip.

11. An energy absorbing strip for a vehicle steering column, comprising: a radially outer leg, the radially outer leg comprising a first radially extending flange and a second radially extending flange; center leg; radial inner legs; a first curved section connecting the radially outer leg and the center leg; and A second curved section connects the center leg and the radially inner leg.

12. The energy absorbing strip of claim 11, wherein the radially extending flange is directly coupleable to a telescoping drive nut.

13. The energy absorbing strip of claim 11 further comprising a pair of anti-roll tabs extending from the radially inner leg.

14. The energy absorbing strip of claim 11, wherein the energy absorbing strip is coupleable to an upper jacket of the vehicle steering column using an anti-lift fastener positioned within a slot defined by the center leg proximate the first curved section.

15. The energy absorbing strip of claim 11, wherein the energy absorbing strip is coupleable to an upper jacket of the vehicle steering column using a locking tab extending from the radially inner leg.

16. The energy absorbing strip of claim 15, wherein the locking tab comprises a shank and a head section.

17. A method of assembling an energy absorbing strip to a steering column, comprising: orienting the energy absorbing strip perpendicular to a longitudinal axis of the steering column; positioning a locking tab within an hourglass-shaped aperture defined by an upper jacket of the steering column; as well as The energy absorbing strip is rotated 90 degrees to orient the energy absorbing strip parallel to the longitudinal axis of the steering column.

18. The method of claim 17, further comprising inserting an anti-lift fastener into a slot defined by the energy absorbing strip and into the upper jacket.

19. The method of claim 17, further comprising coupling the energy absorbing strap directly to a telescoping drive nut of a telescoping drive assembly.

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