Power release and locking adjustable steering column apparatus and method

A steering column is provided column including a bracket adapted to enable the steering column to move as desired by an operator and a clamping system adjacent to the bracket. The clamping system includes a threaded member. A threaded clamping stud extends through the bracket. The threaded clamping stud is selectively coupled to the threaded member of the clamping device. A transmission is coupled to the threaded member. A motor is coupled to the transmission. The motor is operable to drive the transmission to rotate the threaded member in a first position to unclamp the bracket to enable the steering column to move based on receipt of an input from the operator.

FIELD

The present invention relates generally to steering systems, and more particularly to a power release and locking adjustable steering column.

BACKGROUND

Vehicle steering columns are often provided with a tiltable component that enables the steering wheel to be set at varying degrees of tilt according to the desires and needs of different operators. Typically, a manually operable lock mechanism is provided for retaining the steering wheel component in selected positions of tilt adjustment.

Most manually operable lock mechanisms require the operator to pull a lever or other device in order to unlock the steering column. This lever must then be repositioned to relock the steering column after the steering column is pivoted. This is undesirable for some users who would prefer an automatic locking and unlocking steering column.

SUMMARY

The present invention provides a steering column including a bracket adapted to enable the steering column to move as desired by an operator and a clamping system adjacent to the bracket. The clamping system includes a threaded member and a reaction cam. The reaction cam is responsive to an input from the threaded member to selectively engage a surface of the bracket. A threaded clamping stud extends through the bracket. The threaded clamping stud is selectively coupled to the threaded member of the clamping device to prevent the movement of the steering column. A transmission is coupled to the threaded member. A motor is coupled to the transmission. The motor is operable to drive the transmission to rotate the threaded member into a first position to unclamp the bracket to enable the steering column to move based on receipt of an input from the operator.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

The following description of the various embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

The present invention is generally related to a power release and locking adjustable steering column. Although the following exemplary description refers to a tilt steering column, it will be understood that the present invention is applicable to a tilt and telescoping steering column or other steering columns in general. It will also be understood that the motor vehicle referenced below is an exemplary vehicle, and the foregoing methodology, as applied to this motor vehicle, is applied to any variety of motor vehicles. Further, the foregoing description is understood to not limit the appended claims.

Referring toFIGS. 1 and 2, the present invention is directed to a power release and locking system10for a steering column12for a motor vehicle8. The steering column12is supported by a fixed surface of a vehicle compartment14, such as an instrument panel (not specifically shown). The locking system10allows the steering column12to move with respect to the vehicle compartment14.

Generally, the steering column12includes a shaft16and a jacket20. The shaft16extends through the jacket20, and has a first end22and a second end24. The shaft16generally is configured to collapse in the event of a crash event. The first end22is coupled to a steering system (not specifically shown) of the vehicle8. The second end24of the shaft16is configured to receive a steering wheel26. The shaft16is rotatably coupled to the jacket20to enable a rotary input from an operator (not shown) to be transmitted to the steering system of the vehicle8.

The jacket20of the steering column12includes a first mounting point, such as a guide bracket28, and a second mounting point30. Generally, the guide bracket28couples the jacket20of the steering column12to a lower mounting point in the vehicle compartment14(not specifically shown). The second mounting point30couples the jacket20of the steering column12to an upper mounting point in the vehicle compartment14(not specifically shown). The second mounting point30is coupled to a translating bracket or bracket36.

The bracket36is integrally formed with the guide bracket28, or is coupled to the second mounting point30of the jacket20through any appropriate technique, such as through mechanical fasteners or welding. The bracket36is formed of a metal or metal alloy, such as magnesium, steel or other suitable materials. The bracket36generally defines two apertures or slots38. The slots38is defined in the bracket36via any suitable technique, such as casting, forming or machining. The slots38enables the steering column jacket20to move, pivot or tilt with respect to the vehicle compartment14, as will be described in greater detail herein. The slots38is also configured for receipt of a portion of the locking system10therein.

With reference toFIGS. 2 and 3, the locking system10includes a motor40coupled to a transmission42. The transmission42is coupled to a clamping system43. The motor40is any suitable motor, but generally is a DC motor. The motor40includes a driveshaft41, which defines a worm44. The worm44is rotatably coupled with the transmission42. The motor40further includes at least one or a plurality of U-shaped flanges46with bent edges48. The plurality of U-shaped flanges46generally is formed on a motor housing49. The U-shaped flanges46is generally coupled at a first end50and a second end52of the motor40to enable the motor40to slidably engage a rail assembly54.

With additional reference toFIG. 5, the rail assembly54includes a rail56having a protrusion58extending the length of the rail56to engage the U-shaped flanges46of the motor40. Generally, the rail56has a thickness T, which enables the rail56to be slidably coupled to the motor40via the bent edges48. The rail56also defines an aperture60for receipt of a pin62therein. The pin62couples the rail56to a supporting bracket64formed on the jacket20of the steering column12. Typically, the rail assembly54is designed so that the rail assembly54reacts to the torque of the motor40to prevent the unlocking of the locking system10in the event of a collapse of the steering column12. In addition, the rail assembly54enables the motor40to collapse with the steering column12, as will be described in greater detail herein.

With reference now toFIGS. 2 and 3, the transmission42is coupled to the motor40via the worm44. Generally, the transmission42includes a worm gear66rotatably coupled to the worm44and a spur gear68rotatably coupled to the worm gear66. At least a portion of the worm44, worm gear66and spur gear68is enclosed by a transmission housing70. The transmission housing70is integrally formed with the motor housing49, if desired. The spur gear68includes an aperture72for receipt of the clamping system43therein. The transmission housing70also generally includes a throughbore73to enable the aperture72to engage the clamping system43.

With continuing reference toFIGS. 2 and 3, and additional reference toFIG. 4, the clamping system43includes a threaded member74configured to be coupled to a tilt clamp stud76. The threaded member74includes a first end78, a second end80and a throughbore82defining a plurality of threads83. The first end78is generally conical in shape and define an inner cavity84with an apex85. The inner cavity84includes a radial groove86for receipt of a guide bushing assembly88.

The guide bushing assembly88includes an annular bearing surface90coupled to a bearing retainer92. The guide bushing assembly88defines a throughbore94for receipt of the tilt clamp stud76therein. In effect, the guide bushing assembly88aligns the tilt clamp stud76with the threaded member74, as will be discussed in greater detail herein. The annular bearing surface90is composed of a polymeric material, but metals or metal alloys may be employed. The bearing retainer92also includes an annular flange96. The annular flange96is configured to mate with the radial groove86defined in the inner cavity84. Generally, a diameter DR of the radial groove86is slightly larger than a diameter DR2of the annular flange96to enable the bearing retainer92to be press-fit into the inner cavity84of the threaded member74(FIG. 4). The bearing retainer92includes at least one or a plurality of retaining teeth98for coupling a thrust bearing assembly100to the bearing retainer92, and thus, the threaded member74(FIG. 3).

The thrust bearing assembly100includes a caged race assembly or a thrust bearing assembly102and a reaction cam104. The thrust bearing assembly102includes an inner cage or ring106and an outer cage or ring108surrounding a race assembly110. Each of the inner ring106, outer ring108and race assembly110defines a throughbore112. The throughbore112generally has a diameter D1, which is greater than a diameter D2of the annular bearing surface90so that the thrust bearing assembly102is received onto the bearing retainer92.

The race assembly110comprises a needle bearing or a roller bearing assembly, depending upon the torque created by the motor40. The inner ring106generally is disposed adjacent to the first end78of the threaded member74, while the outer ring108is disposed against the reaction cam104. The reaction cam104is comprised of a metal or metal alloy, and generally is sized with a diameter D3, which is greater than a diameter D4of the thrust bearing assembly102. The reaction cam104includes a first side114and a second side116. The first side114is positioned adjacent to the outer ring108of the thrust bearing assembly102and the second side116generally is disposed adjacent to the bracket36. The second side116typically applies a locking force F to the bracket36to prevent the steering column12from pivoting, as will be discussed in greater detail herein.

The second end80of the threaded member74generally is cylindrical in shape. The second end80defines a raised annular flange118. The raised annular flange118is configured for receipt of a journal120to support a tilt assist spring122. The journal120enables the threaded member74to rotate without disturbing the tilt assist spring122. The tilt assist spring122provides a resistive force R against the movement of the steering column12, and also serves to return the steering column12to a full-tilt up position (not specifically shown). The second end80also defines a hexagonal portion124adjacent to the raised annular flange118to enable the aperture72of spur gear68of the transmission42to engage the threaded member74. A dust cap125is received on the second end80, adjacent to the transmission housing70, to prevent contaminants from entering the assembly, and to assist in retaining the transmission42on the second end80.

With reference toFIGS. 3 and 4, the tilt clamp stud76of the clamping system43is generally cylindrical and includes a first end126and a second end128. The first end126includes a necked portion130including a plurality of threads132. The necked portion130is positioned on the first end126so that the necked portion130is received adjacent to the apex85of the threaded member74. The plurality of threads132matingly engages the plurality of threads83formed in the throughbore82of the threaded member74to enable the clamping system43to clamp or unclamp the bracket36. The second end128of the tilt clamp stud76includes a formed projection134. The formed projection134is sized so that the formed projection134engages an exterior surface136of the bracket36, but the formed projection134cannot pass through the slot38. The second end128also includes a stem138. A journal140is received on the stem138to support a second tilt assist spring142. The second tilt assist spring142is coupled to an aperture (not specifically shown) formed on the jacket20to facilitate the movement of the steering column12based on the input from the operator (not specifically shown), as will be discussed in greater detail herein.

The locking system10also includes a controller146(FIG. 3). The controller146is coupled to the motor40to energize the motor40based on an input148from an operator (not shown). The input148is in the form of a signal S transmitted from a pushbutton150(FIG. 1), for example, but other input devices may be employed. In order to move or pivot the steering column12, on receipt of the signal S, and as the signal S continues, the controller146energizes the motor40. The motor40, in turn, drives the driveshaft41to drive the worm44, which drives the worm gear66and the spur gear68. The rotation of the spur gear68, in turn, rotates the threaded member74in a first direction to move the reaction cam104away from the bracket36to release the locking force F from the bracket36. Then, the operator moves the steering column12via the steering wheel26into a desired position.

Once the steering column12is in the desired position, the operator releases the pushbutton150. Once the pushbutton150is released, the signal S terminates, and the controller146energizes the motor40to drive the transmission42and rotate the threaded member74in a second direction to tighten the reaction cam104against the bracket36. Once the reaction cam104is tightened against the bracket36, the steering column12is locked into the new position set by the operator.

With reference now toFIG. 6, in the event of a collapse of the steering column12during a crash event, the shaft16of the steering column12collapses and the jacket20is sheared from the second mounting point30of the vehicle compartment14(not shown). During the collapse of the steering column12, the motor40slides down the rail56with the steering column12so that the clamping system43stays locked during a crash event. Generally, an axis A of the motor40in a collapsed state will be parallel to an axis A1of the shaft16of the steering column12in the collapsed state to protect the occupant.

The description of these teachings is merely exemplary in nature and, thus, variations that do not depart from the gist of the teachings are intended to be within the scope of the teachings. Such variations are not to be regarded as a departure from the spirit and scope of the teachings.