Steering assembly

A steering assembly includes a steering member and an adjustment assembly. The steering member has a first side, a second side adjacent the first side, a third side adjacent the second side and disposed opposite the first side, and a fourth side adjacent the third side and disposed opposite the second side. The adjustment assembly includes a first adjustment member and a second adjustment member. The first adjustment member is arranged to apply a first biasing force to the first side and a second biasing force to the second side. The second adjustment member is arranged to engage the third side and the fourth side.

BACKGROUND

Steering systems may employ a ball screw that converts a rotational input into a linear steering output to pivot at least one vehicle road wheel. A rack assist electric power steering system may include a ball screw that is fixed to a member, such as a rack. In such a system, a ball screw torque may cause rotation of the member that may result in an error in steering gear and rack mesh alignment.

SUMMARY

Disclosed is a steering assembly that includes a non-cylindrical steering member and an adjustment assembly. The non-cylindrical steering member extends along a central axis between a first end and a second end through a housing. The non-cylindrical steering member has a first side, a second side extending from the first side, a third side extending from the second side and disposed opposite the first side, and a fourth side extending from the third side and disposed opposite the second side. The adjustment assembly includes a first adjustment member and a second adjustment member. The first adjustment member is arranged to apply a first biasing force to the first side and a second biasing force to the second side. The second adjustment member is arranged to engage the third side and the fourth side.

Also disclosed is a steering assembly that includes a steering member and an adjustment assembly. The steering member has a first side, a second side adjacent the first side, a third side adjacent the second side and disposed opposite the first side, and a fourth side adjacent the third side and disposed opposite the second side. The adjustment assembly includes a first adjustment member and a second adjustment member. The first adjustment member is arranged to apply a first biasing force to the first side and a second biasing force to the second side. The second adjustment member is arranged to engage the third side and the fourth side.

DETAILED DESCRIPTION

Referring toFIGS. 1-3, a steering assembly10is shown. The steering assembly10may be provided with an autonomous vehicle, a partially autonomous vehicle, semi-autonomous vehicle, a selectively autonomous vehicle or a conventional vehicle. The steering assembly10may be a ball screw assisted steering system having a steering member12, a ball screw14, and an adjustment assembly16.

The steering member12may be a non-cylindrical steering member having a prismatic bar with a polygonal section or may have a substantially rectangular, rhomboid, or square prismatic shape having sides that are disposed orthogonal to each other. The non-cylindrical steering member12extends along a central axis22between a first end24and a second end26through a housing54. The non-cylindrical steering member12may present greater section properties as compared to traditional round steering racks.

The non-cylindrical steering member12includes a first side30, a second side32extending from the first side30, a third side34extending from the second side32, and a fourth side36extending from the third side34. The second side32is disposed adjacent to or orthogonal to the first side30and the third side34. The third side34is disposed adjacent to or orthogonal to the second side32and the fourth side36. The third side34is disposed substantially opposite the first side30. The fourth side36is disposed adjacent to or orthogonal to the third side34and the first side30. The fourth side36is disposed substantially opposite the second side32.

The non-cylindrical steering member12defines a first edge40and a second edge42that is disposed opposite the first edge40, as shown inFIGS. 1 and 2. The first edge40is defined between or defined at a junction between the first side30and the fourth side36. The second edge42is defined between or defined at a junction between the second side32and the third side34.

The ball screw14may extend into the first end24of the non-cylindrical steering member12. The ball screw14and the non-cylindrical steering member12may be formed as separate components that are later joined together at a joint such as a vented light press male-female joint within interfacial weld where position and orientation of the ball screw14and the non-cylindrical steering member12are controlled by the cylindrical interface. The ball screw14and the non-cylindrical steering member12may be joined with friction weld, laser weld, or other similar joint. The ball screw14and the non-cylindrical steering member12may be integrally formed together. At least one tie rod or other connection member extends from the second end26of the non-cylindrical steering rack12and/or the outboard end of ball screw14. The ball screw14engages a ball nut, a series of ball members, and a powered transmission to convert rotary motion into linear motion that translates the non-cylindrical steering member12along the central axis22to cause the tie rod or connection member to pivot and/or steer at least one vehicle wheel.

The adjustment assembly16includes a first adjustment member50that is arranged to engage a first pair of adjacent surfaces or orthogonal surfaces of the non-cylindrical steering member12and includes a second adjustment member52that is arranged to engage a second pair of adjacent surfaces or orthogonal surfaces of the non-cylindrical steering member12that are disposed substantially opposite the first pair of adjacent surfaces. The first adjustment member50and the second adjustment member52are physically independent of each other and independently apply biasing forces to surfaces of the non-cylindrical steering member12to at least apply ball-nut torque reaction forces to inhibit rotation of the non-cylindrical steering member12and the ball screw14about the central axis22. The first adjustment member50and the second adjustment member52may extend through or be supported by a housing54through which the non-cylindrical steering member12extends.

The first adjustment member50is arranged to apply a first biasing force to the first side30and is arranged to apply a second biasing force to the second side32. The first adjustment member50includes a first reaction pad62, a first plunger64, a first adjuster plug66, and a first biasing member68.

The first reaction pad62extends at least partially across the first side30and the second side32of the non-cylindrical steering member12. The first reaction pad62may include separate and distinct reaction pads having a first pad portion that engages the first side30and a separate and distinct second pad portion that engages the second side32. The first pad portion and the second pad portion being spaced apart from each other at a junction between the first side30and the second side32. The first reaction pad62defines a first engagement surface72disposed adjacent to or engages the first side30and a second engagement surface74disposed adjacent to or engages the second side32.

The first reaction pad62may be affixed to the first plunger64through a common backing that is affixed to the first plunger64or may be at least partially disposed within or extends into the first plunger64, as shown inFIGS. 2 and 3. The first reaction pad62may be integrally formed with the first plunger64such that the first reaction pad62is a raised surface of the first plunger64that engages adjacent or orthogonal surfaces of the non-cylindrical steering member12.

The first plunger64fits into a first bore of the housing54and is arranged to move within the first bore. The first plunger64at least partially receives or defines the first reaction pad62. The first plunger64extends between a first plunger first end80and a first plunger second end82. The first reaction pad62may be at least partially disposed in a first cavity or a first relief83that extends from the first plunger first end80towards the second plunger end82. The first plunger64defines a first plunger cavity84that extends from the first plunger second end82towards the first plunger first end80.

The first plunger64defines a v-shaped or notched first region86that extends from the first plunger first end80towards the first plunger second end82. The first region86is arranged to receive at least a portion of the first side30and the second side32of the non-cylindrical steering member12. The first region86includes a pair of surfaces that are disposed in a non-parallel relationship with respect to each other.

Referring toFIGS. 1 and 3, the first adjuster plug66extends at least partially through the housing54through which the non-cylindrical steering member12extends. The first adjuster plug66is provided with external threads that engage with the housing54to position the first adjuster plug66. The first adjuster plug66is movably or adjustably connected to the housing54and/or the first plunger64.

The first adjuster plug66extends between a first adjuster plug first end90and a first adjuster plug second end92. The first adjuster plug first end90is disposed proximate the first plunger second end82. The first adjuster plug first end90may be movable relative to the first plunger second end82. The first adjuster plug66defines a first adjuster plug cavity94that extends from the first adjuster plug first end90towards the first adjuster plug second end92.

Referring toFIG. 3, the first biasing member68is disposed within or extends between the first plunger64and the first adjuster plug66. The first biasing member68extends between the first adjuster plug cavity94and the first plunger cavity84. The first biasing member68is arranged to apply a biasing force to the first plunger64such that the first biasing force is applied to the first side30and the second biasing force is applied to the second side32through the first reaction pad62. The movement of the first adjuster plug66relative to the first plunger64varies the first biasing force and varies the second biasing force. During operation the position of first adjuster plug66is established with respect to the housing54, for example by a threaded connection, such that a small initial gap exists between the first plunger second end82and the first adjuster plug first end90. The first biasing member68pushes or urges the first plunger64into contact with non-cylindrical steering member12. Steering assist and tie rod loads may cause displacement of the first plunger64along a centerline axis98of the adjustment member50,52that is disposed transverse to the central axis22against the restoring force of the first biasing member68and/or the first adjuster plug66. This displacement is limited by the initial gap between the first plunger second end82and the first adjuster plug first end90.

The second adjustment member52is disposed opposite the first adjustment member50. The second adjustment member52may be disposed directly opposite the first adjuster member50or may be disposed opposite the first adjustment member50but axially spaced apart from the first adjustment member50along the central axis22. The second adjustment member52is arranged to engage the third side34and the fourth side36of the non-cylindrical steering member12.

The second adjustment member52may be affixed, unsprung, to the housing54through which the non-cylindrical steering member12at least partially extends. The second adjustment member52may be arranged to apply a third biasing force to the third side34and a fourth biasing force to the fourth side36should the second adjustment member52to affixed, sprung, to the housing54through which the non-cylindrical steering member12at least partially extends.

The second adjustment member52includes a second reaction pad102, a second plunger104, a second adjuster plug106, and a second biasing member108.

The second reaction pad102extends at least partially across the third side34and the fourth side36of the non-cylindrical steering member12. The second reaction pad102may include separate and distinct reaction pads having a first pad portion that engages the third side34and a separate and distinct second pad portion that engages the fourth side36. The first pad portion and the second pad portion being spaced apart from each other at a junction between the third side34and the fourth side36. The second reaction pad102defines a third engagement surface112disposed adjacent to or engages the third side34and a fourth engagement surface114disposed adjacent to or engages the fourth side36.

The second reaction pad102may be affixed to the second plunger104through a common backing that is affixed to the second plunger104or may be at least partially disposed within or extends into the second plunger104, as shown inFIGS. 2 and 3. The second reaction pad102may be integrally formed with the second plunger104such that the second reaction pad102is a raised surface of the second plunger104that engages adjacent or orthogonal surfaces of the non-cylindrical steering member12.

The second plunger104fits into a second bore of the housing54that may be aligned with the first bore that receives the first plunger64. The second plunger104is arranged to move within the second bore. The second plunger104at least partially receives or defines the second reaction pad102. The second plunger104extends between a second plunger first end120and a second plunger second end122. The second reaction pad102may be at least partially disposed in a second cavity or second relief123that extends from the second plunger first end120towards the second plunger second end122. The second plunger104defines a second plunger cavity124that extends from the second plunger second end122towards the second plunger first end120.

The second plunger104defines a v-shaped or notched second region126that extends from the second plunger first end120towards the second plunger second end122. The second region126is arranged to receive at least a portion of the third side34and the fourth side36of the non-cylindrical steering member12. The second region126includes a pair of surfaces that are disposed in a non-parallel relationship with respect to each other.

The first plunger first end80is spaced apart from the second plunger first end120such that the first edge40of the non-cylindrical steering member12extends into a first void130and the second edge42of the non-cylindrical steering member12extends into a second void132that is disposed opposite the first void130, as shown inFIG. 2.

Referring toFIGS. 1 and 3, the second adjuster plug106extends at least partially through the housing54through which the non-cylindrical steering member12extends. The second adjuster plug106is provided with external threads that engage with the housing54to position the adjuster plug66. The second adjuster plug106is movably or adjustably connected to the housing54and/or connected to the second plunger104.

The second adjuster plug106extends between a second adjuster plug first end140and a second adjuster plug second end142. The second adjuster plug first end140is disposed proximate the second plunger second end122. The second adjuster plug first end140may be movable relative to the second plunger second end122. The second adjuster plug106defines a second adjuster plug cavity144that extends from the second adjuster plug first end140towards the second adjuster plug second end142.

Referring toFIG. 3, a second biasing member108may be disposed within or between the second plunger104and the second adjuster plug106. The second biasing member108extends between the second adjuster plug cavity144and the second plunger cavity124. The second biasing member108is arranged to apply a biasing force to the second plunger104such that a third biasing force is applied to the third side34and a fourth biasing force is applied to the fourth side36through the second reaction pad102. The movement of the second adjuster plug106relative to the second plunger104varies the third biasing force and varies the fourth biasing force. During operation the position of second adjuster plug104is established with respect to the housing54, for example by a threaded connection, such that a small initial gap may exist between the second plunger second end122and the second adjuster plug first end140. The second biasing member108or the second adjuster plug106when unspring, pushes or urges the second plunger104into contact with non-cylindrical steering member12. Steering assist and tie rod loads may cause displacement of the second plunger14along the centerline axis98of the adjustment member50,52that is disposed transverse to the central axis22against the restoring force of the second biasing member108and/or the second adjuster plug106. This displacement is limited by the initial gap between the second plunger second end122and the second adjuster plug first end140.

Should the second biasing member108not be provided with the second adjustment member52, the third biasing force and the fourth biasing force may instead be reaction forces. In such an arrangement, a first reaction force results proximate the third side34in reaction to the first biasing force applied to the first side30of the non-cylindrical steering member12. Further, a second reaction force results proximate the fourth side36in reaction to the second biasing force applied to the second side32of the non-cylindrical steering member12.

The first adjustment member50and the second adjustment member52of the adjustment assembly16interface with the prismatic polygon shape of the non-cylindrical steering member12to provide an anti-rotate function. The first adjustment member50and the second adjustment member52provide reaction locations or reaction surfaces to oppose the rotation or twisting of the combination of the non-cylindrical steering member12and the ball screw14about the central axis22.