Patent Application
20090090210
1. Field of the Invention
The subject invention generally relates to a steering column assembly for a vehicle, and more specifically to a collapsible steering column assembly having an energy absorption system for absorbing energy during collapse of the steering column assembly.
2. Description of the Prior Art
Vehicle steering column assemblies are typically equipped with a kinetic energy absorption system. The energy absorption system reduces the likelihood or severity of an operator of the vehicle from being injured in the event of a collision that may cause the operator to impact a steering wheel attached to the steering column assembly. Such impacts during vehicle collisions typically cause the steering column assembly to collapse, thereby absorbing some of the energy that my otherwise be transmitted to the operator.
Such collapsible steering column assemblies generally include a housing that translates linearly through a collapse stroke during the collision. A force generated by the driver impacting the steering wheel initiates the collapse stroke. The steering wheel housing moves against a resisting or reactive force that is produced by the energy absorption system, which is designed to convert a portion of the driver's kinetic energy into work. The resisting force is typically generated by plastically deforming a metal element.
Typically, the collapsible steering column assembly includes a column jacket having an output end and a steering wheel attachment end. A bracket is mounted to the column jacket for attaching the column jacket to the vehicle. At least one, but preferably a pair of release modules releasably interconnects the bracket to the vehicle. The release modules may include a single bore, through which a fastener, such as a bolt, passes through to fixedly connect the release module to the vehicle. The energy absorption system typically includes a metal strap connected to the bracket for movement with the bracket and the column jacket during the collapse stroke. The strap passes through a deformation device, which includes a channel defining an anvil about which the strap is deformed. Often, the deformation channel is incorporated into the release module.
Traditionally, the channel has been disposed opposite the release module fastener from the point of attachment where the strap is connected to the bracket. Accordingly, if the fastener connecting the release module to the vehicle is not properly tightened or slips, as the column jacket moves along the longitudinal axis during collapse, the strap will pull on the channel and cause the channel to rotate about the release module fastener, thereby preventing the energy absorption system from functioning properly.
The subject invention provides a steering column assembly for a vehicle. The steering column assembly comprises a column jacket. The column jacket is longitudinally collapsible along a longitudinal axis in response to a collision event. A release module is releasably coupled to the column jacket. The release module includes a connection point for connecting the release module to the vehicle. The release module is coupled to the column jacket prior to the longitudinal collapse of the column jacket, and is releasable from the column jacket in response to the longitudinal collapse of the column jacket. An energy absorption system includes a deformation device disposed on the release module and a strap. The strap includes an attachment point for attaching the strap to the column jacket. The strap extends through the deformation device such that the strap is drawn through and deformed by the deformation device in response to the longitudinal collapse of the column jacket to absorb energy. The attachment point is laterally offset from a first position along the longitudinal axis. The connection point is laterally offset from a second position along the longitudinal axis. The second position is spaced from the first position along the longitudinal axis. The deformation channel is laterally offset from a third position along the longitudinal axis. The third position is disposed between the first position and the second position.
Accordingly, the steering column assembly of the subject invention positions the channel of the energy absorption system between the attachment point of the strap to the column jacket and the connection point of the release module to the vehicle. Therefore, during collapse of the column jacket, the strap is drawn through the channel and pulls against the connection point of the release module. Thus, even if the release module is not properly tightened to the vehicle, i.e., is loose, the release module will not rotate about the connection point as the strap is drawn through the channel, thereby ensuring proper functioning of the energy absorption system.
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a steering column assembly is shown generally at 20. The steering column assembly 20 is for a vehicle, and is collapsable in response to a collision event.
Referring to
As shown with reference to
Referring back to
A release module 46 is releasably coupled to the column jacket 22. Specifically, the release module 46 is coupled to the bracket 34. The release module 46 includes a connection point 48 for connecting the release module 46 to the vehicle. The release module 46 is coupled to the column jacket 22 prior to the longitudinal collapse of the column jacket 22, and is releasable from the column jacket 22 in response to the longitudinal collapse of the column jacket 22. The release module 46 couples the bracket 34 and thereby the column jacket 22 to the vehicle prior to the collision event, and releases the bracket 34 and thereby the column jacket 22 from the vehicle in response to movement of the bracket 34 and the column jacket 22 along the longitudinal axis 28.
The release module 46 is fixedly attached to the vehicle, and stays connected to the vehicle after the bracket 34 and the column jacket 22 are released from the release module 46. Typically, the release module 46 includes a first portion fixedly coupled to the column jacket 22 and a second portion fixedly attached to the vehicle and releasably couple to the first portion of the release module 46. The release module 46 includes a plurality of sheer pins 54 interconnecting the first portion of the release module 46 and the second portion of the release module 46. The shear pins are shearable, i.e., fracture, when the column jacket 22 collapses forward along the longitudinal axis 28, thereby disconnecting the first portion and the bracket 34 from the second portion and the vehicle. However, it should be appreciated that the release module 46 may be coupled to the bracket 34 or the column jacket 22 in some other suitable fashion. The release module 46 may include a first release module 46A releasably coupled to the first extension 36 and a second release module 46B releasably coupled to the second extension 38.
The release module 46 includes a bore 56 extending therethrough and concentric with the connection point 48. A release module fastener 42 extends through the bore 56 for fixedly attaching the release module 46 to the vehicle. The release module fastener 42 may include a bolt, a screw or some other suitable fastening device.
The steering column assembly 20 further includes an energy absorption system 58. The energy absorption system 58 interconnects the bracket 34 and thereby the column jacket 22 to the release module 46 and thereby to the vehicle. The energy absorption system 58 includes a strap 60. The strap 60 includes an attachment point 62 for attaching the strap 60 to the column jacket 22. Preferably, the strap 60 is coupled to the bracket 34. The strap 60 is plastically deformable, and is preferably a metal. However, it should be appreciated that the strap 60 may include some other plastically deformable material. The strap 60 is coupled to the bracket 34. The strap 60 may be fixedly connected to the bracket 34. Preferably, the strap 60 is secured to the column jacket 22, i.e., the bracket 34, by a strap fastener 44. The strap fastener 44 may include a screw, bolt, or some other similar fastener. However, it should be appreciated that other devices may be utilized to fixedly connect the strap 60 to the bracket 34. The strap fastener 44 is concentric with the attachment point 62.
Alternatively, the strap 60 may be selectively coupled to the bracket 34. Selectively coupling the strap 60 to the bracket 34 allows for a two stage energy absorption system 58, in which a first stage permits collapse of the column jacket 22 without resistance provided by the energy absorption system 58 by not connecting the strap 60 to the bracket 34, and a second stage in which the energy absorption system 58 does provide resistance against movement of the column jacket 22 by connecting the strap 60 to the bracket 34. An actuator 64 is attached to the bracket 34 in order to selectively couple the strap 60 to the bracket 34. A controller (not shown) signals the actuator 64 to couple the strap 60 to the bracket 34 if desired. The actuator 64, if signaled, may move the strap fastener 44, such as a pin, through an aperture in the strap 60 to connect the strap 60 to the bracket 34. The actuator 64 may include a pyrotechnic device or some other suitable device. However, it should be appreciated that the strap 60 may be selectively coupled to the bracket 34 by some other manner not shown or described herein.
As best shown in
As described above, the channel 68 defines and includes the anvil 70, about which the strap 60 is deformed as the strap 60 is drawn through the channel 68. The anvil 70 is disposed on the release module 46. The channel 68 and the anvil 70 may include any suitable shape. As shown, the channel 68 and the anvil 70 generally define a U-shape. However, it should be appreciated that the resistance provided by the energy absorption system 58 is determined by the amount of energy required to deform the strap 60 as the strap 60 is drawn through the channel 68. Accordingly, a more complex channel 68 having more and/or smaller radius bends, increases the amount of energy required to deform the strap 60 and thereby increases the resistance provided against movement of the column jacket 22.
The attachment point 62 of the strap 60 is laterally offset from a first position 72 along the longitudinal axis 28. The connection point 48 of the release module 46 is laterally offset from a second position 74 along the longitudinal axis 28. The second position 74 is spaced from the first position 72 along the longitudinal axis 28. The deformation device 66, i.e., the channel 68 and the anvil 70, is laterally offset from a third position 76 along the longitudinal axis 28. The third position 76 is disposed between the first position 72 and the second position 74, i.e., between the attachment point 62 of the strap 60 and the connection point 48 of the release module 46.
Accordingly, the anvil 70 is also disposed between the attachment point 62 of the strap 60 and the connection point 48 of the release module 46, i.e., between the first position 72 and the second position 74. Accordingly, it should be appreciated that during the collapse stroke of the steering column assembly 20, as the column jacket 22 moves along the longitudinal axis 28 and draws the strap 60 through the channel 68, the channel 68 and the anvil 70 will not be able to rotate about the release module fastener 42 connecting the release module 46 to the vehicle, even if the release module fastener 42 is not properly tightened, thereby ensuring proper functioning of the energy absorption system 58.
Referring back to
The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. As is now apparent to those skilled in the art, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, wherein reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/977,822, filed on Oct. 5, 2007, the disclosure of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60977822 | Oct 2007 | US |
