Steering column assembly and method for installing a tilt actuator assembly in a steering system

Abstract

Steering column assembly (44), comprising: a sheath (50) that is functionally coupled to a fastening structure (70); and a tilt actuator assembly (52) which is functionally coupled to the sheath (50) and the mounting structure (70) to adjust a tilt position of the sheath (50), wherein the tilt actuator assembly (52) comprises: an electric actuator (72); a lead screw (76) which is driven by the electric actuator (72); an actuator nut (78) which is displaced along the lead screw (76) during rotation of the lead screw (76), the actuator nut (78) having a main body (80) surrounding the lead screw (76) and a retaining section (82) extending from the main body (80), the retaining section (82) having a retaining tab (88) extending radially outwards; and a tilting bracket (86) which is functionally coupled to the sheath (50) and defines a bracket opening (84), wherein the bracket opening (84) includes an access slot (90) which is dimensioned to accommodate the retaining tab (88), wherein the retaining tab (88) prevents the actuator nut (78) from being pulled out of the bracket opening (84) when fully inserted through the access slot (90) and when the actuator nut (78) is rotated to disalign the retaining tab (88) and the access slot (90).

Description

FIELD OF THE INVENTION

[0001] The present disclosure relates to steering column assemblies and a method for incorporating a tilt actuator assembly into a steering system. BACKGROUND

[0002] A vehicle, such as a passenger car, truck, sport utility vehicle, crossover, minivan, watercraft, aircraft, off-road vehicle, recreational vehicle, or other suitable vehicles, includes various steering system schemes, such as steer-by-wire, mechanical linkage, and autonomous steering capability. These steering system schemes typically include a steering column assembly for translating a steering input into an output, which interacts with a steering linkage to ultimately cause the vehicle's wheels to turn.

[0003] Steering column assemblies are designed with features that allow the steering column assembly to be raised or lowered, known as tilt adjustability. Some steering columns require manual tilt adjustment, while others use an electric actuator to perform adjustments. In an electric actuator assembly, an electric actuator provides an output that causes movement on a tilt bracket via a nut and lead screw arrangement. Movement of the tilt bracket adjusts the tilt position of the steering column.

[0004] DE 10 2021 123 712 A1 discloses a steering column assembly comprising: a shell operatively coupled to a mounting structure; and a tilt actuator assembly operatively coupled to the shell and the mounting structure to adjust a tilt position of the shell, wherein the tilt actuator assembly comprises: an electric actuator; a lead screw driven by the electric actuator;an actuator nut that is displaced along the lead screw during rotation of the lead screw, the actuator nut having a main body surrounding the lead screw and having extensions with wrench flats on opposite sides, and a tilt bracket operatively coupled to the shell and defining a bracket opening on either side relative to the lead screw, each bracket opening including an access slot sized to allow the actuator nut to be inserted into the bracket opening with its respective wrench flats along the slot. Withdrawal of the actuator nut perpendicular to the lead screw and perpendicular to the tilt axis of the steering column from the bracket opening is prevented upon full insertion through the access slot and upon rotation of the actuator nut to dealign the respective wrench flats and the associated access slot.

[0005] DE 10 2018 202 795 A1 discloses a steering column assembly with a structure that corresponds to the structure of the steering column assembly of DE 10 2021 123 712 A1, in particular with regard to the fastening of the actuator nut to the tilt bracket via wrench surfaces of an otherwise round body that can be inserted into a slot.

[0006] DE 10 2019 132 281 A1 teaches a steering column assembly comprising: a shell operatively coupled to a mounting structure; and a mounting bracket arm defining a first mounting bracket opening, and a second mounting bracket arm defining a second mounting bracket opening, and a tilt bracket assembly enabling movement of the shell about a rotation axis.The tilt bracket assembly includes a first tilt bracket coupleable to the first mounting bracket arm, the first tilt bracket defining a first opening of the first tilt bracket arranged coaxially with the first mounting bracket opening, and a second opening of the first tilt bracket along a first axis; and a second tilt bracket coupleable to the second mounting bracket arm, the second tilt bracket defining a first opening of the second tilt bracket arranged coaxially with the second mounting bracket opening, and a second opening of the second tilt bracket arranged coaxially with the second opening of the first tilt bracket along a second axis. First and second pivot bushings are press-fitted into the first and second openings of the first tilt bracket, respectively. The first and second pivot fasteners are fitted into the first and secondsecond pivot bushing and press-fitted into the first and second mounting bracket openings of the first and second mounting bracket arms of the mounting bracket, respectively. A pin is press-fitted into the first and second openings of the first and second tilt brackets, respectively, using material displacement.

[0007] DE 10 2005 033 626 A1 discloses a clamping piece for connecting an intermediate shaft to a pinion shaft of a steering gear of a motor vehicle. The clamping piece has two side cheeks that receive the pinion shaft while clamping the side cheeks with a clamping screw. The clamping screw has an actuatable threaded element at one end that cooperates with a threaded portion of the clamping screw. The clamping screw has a clamping device for engaging the clamping screw against a side cheek at the end opposite the threaded element. The clamping screw has at least one pressure section between the threaded element and the clamping device, protruding radially from the outer surface of the clamping screw.

[0008] Pre-positioning the tilt actuator on the steering column requires the correct position of the actuator nut on the lead screw and the correct positioning of the tilt bracket during assembly. This can lead to longer assembly times and require assembly personnel to force the actuators into position, potentially damaging the components.

[0009] The object of the present invention is to provide a steering column assembly with a more reliable, efficient and cost-effective tilt actuator assembly and associated installation method.

[0010] This object is achieved by a steering column assembly having the features of claim 1 and a method for installing a tilt actuator assembly in a steering system having the features of claim 8.

[0011] Advantageous embodiments are specified in the dependent claims. SUMMARY OF REVELATION

[0012] According to one aspect of the disclosure, a steering column assembly includes a shell operatively connected to a mounting structure. The steering column assembly also includes a tilt actuator assembly operatively coupled to the shell and the mounting structure to adjust a tilt position of the shell. The tilt actuator assembly includes an electric actuator. The tilt actuator assembly also includes a lead screw driven by the electric actuator. The tilt actuator assembly further includes an actuator nut that translates along the lead screw during rotation of the lead screw, the actuator nut having a main body surrounding the lead screw and a retention portion extending from the main body, the retention portion having a retention tab that extends radially outward.The tilt actuator assembly further comprises a tilt bracket operatively coupled to the shell and defining a bracket opening, the bracket opening including an access slot sized to receive the retention tab, the retention tab preventing withdrawal of the actuator nut from the bracket opening upon full insertion through the access slot and upon rotation of the actuator nut to de-align the retention tab and the access slot.

[0013] According to another aspect of the disclosure, a tilt actuator assembly for a vehicle steering system includes an electric actuator. The tilt actuator assembly also includes a lead screw driven by the electric actuator. The tilt actuator assembly further includes an actuator nut that translates along the lead screw during rotation of the lead screw. The tilt actuator assembly further includes a lead screw housing having a mounting recess or hole sized to receive a mounting boss extending from a mounting structure.

[0014] According to another aspect of the disclosure, a method for installing a tilt actuator assembly into a steering system is provided. The method includes aligning a plurality of retaining tabs of an actuator nut, wherein a first side of a plurality of access slots is defined by a bracket opening of a tilt bracket. The method also includes inserting the plurality of retaining tabs through the plurality of access slots until the plurality of retaining tabs are located on a second side of the plurality of access slots. The method further includes rotating the actuator nut until the plurality of retaining tabs are out of alignment with the plurality of access slots to prevent withdrawal of the actuator nut from the tilt bracket.

[0015] These and other advantages and features will become clearer from the following description taken in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The subject matter regarded as the invention is particularly pointed out and particularly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. Figure 1 is a schematic representation of a vehicle steering system; Fig. 2 is a perspective view of a tilt actuator assembly for the vehicle steering system in an installed condition; Fig. 3 is a perspective view of a first side of the tilt actuator assembly in a first installation process state; Fig. 4 is a perspective view of a second side of the tilt actuator assembly in the first installation process state; Fig. 5 is a perspective view of the first side of the tilt actuator assembly in a second installation process state; Fig. 6 is a perspective view of the first side of the tilt actuator assembly in a third installation process state; Fig. 7 is a perspective view of a retaining portion of an actuator nut inserted into a tilt bracket hole in an installation process state of the actuator nut; Fig. 8 is a perspective view of the retaining portion of the actuator nut rotated in another installation process state of the actuator nut; Fig. 9 is a perspective view of the second side of the tilt actuator assembly in a fourth installation process state; Fig. 10 is a perspective view of the first side of the tilt actuator assembly in the fourth installation process state; Fig. 11 is a perspective view of a mounting feature for positioning the tilt actuator assembly during installation; Fig. 12 is a perspective view of a lead screw housing of the tilt actuator assembly; and Fig. 13 is a perspective view of a tilt actuator assembly for the vehicle steering system in the installed state. DETAILED DESCRIPTION

[0017] With reference first to Fig. 1, a vehicle 20 is schematically illustrated in accordance with the principles of the present disclosure. The vehicle 20 may be 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. While the vehicle 20 may be a wheeled passenger vehicle intended for over-the-road travel, the principles of the present disclosure may also apply to other vehicles, such as aircraft, tractors, boats, or other types of vehicles.

[0018] The vehicle 20 includes a steering system 40, which may be configured as a driver interface steering system, an autonomous driving system, or a system enabling both a driver interface and autonomous steering. The steering system 40 may include an input device 42, such as a steering wheel, that a driver can use to mechanically provide a steering input by turning the steering wheel. A steering column assembly 44 includes a steering column 45 extending along an axis from the input device 42 to an output assembly 46. The output assembly 46 may include a pinion shaft assembly, an I-shaft, a universal joint, steer-by-wire components, or any other features conventionally disposed opposite the input device 42.

[0019] A steering gear assembly 54 may be connected to the output assembly 46 via a steering gear input shaft 56. The steering gear assembly 54 may be configured as a rack and pinion, a recirculating ball steering system, or other types of steering gears associated with autonomous and driver interface steering systems. The steering gear assembly 54 may then be connected to a drive axle 58 via an output shaft 60. The output shaft 60 may include a pitman arm and a sector gear or other conventional components. The output shaft 60 is operatively connected to the steering gear assembly 54 such that rotation of the steering gear input shaft 56 causes a corresponding movement of the output shaft 60, causing the drive axle to rotate the wheels 61.It is to be understood that a steer-by-wire system may be used with the embodiments disclosed herein such that a mechanical connection is not continuous throughout the components described above.

[0020] The steering column 45 includes one or more shrouds surrounding a steering shaft assembly (not shown). In particular, a single shroud may be provided or multiple shrouds may be included. In the illustrated example, two axially adjustable sections are provided, namely a first shroud 48 and a second shroud 50, which are axially adjustable relative to one another. The first shroud 48 may be an upper shroud and a second shroud 50 may be a lower shroud, wherein the first shroud 48 and the second shroud 50 may move axially relative to one another in a sliding, telescoping, translatable, and / or other axial movement manner. It should be noted that three or more shrouds may equally be contemplated.In addition to the axial movement of the shroud(s), the steering column 45 is adjustable in a tilt direction that pivots the steering column 45 about an axis substantially perpendicular to the longitudinal axis of the steering column. Tilt adjustment changes the vertical position of the steering input device 42. In the illustrated embodiment, the second shroud 50 (e.g., the lower shroud 50) is pivoted by a tilt actuator assembly 52.

[0021] Now with reference to Fig. 2, the tilt actuator assembly 52 is shown in detail. Specifically, the tilt actuator assembly 52 is shown attached to a mounting structure 70 and a portion of a shroud (e.g., the second / lower shroud 50). The mounting structure 70 may be any structure that is stationary with respect to the shroud(s), such as a mounting bracket that operatively couples the steering column 45 to the vehicle 20.

[0022] The tilt actuator assembly 52 includes an electric actuator 72, such as an electric motor of any suitable type. The electric actuator 72 includes an output shaft that engages a gear assembly. The output shaft and gear assembly are disposed within a housing 74 and are therefore not shown. The gear assembly transmits motion of the electric actuator output shaft to a lead screw 76, with a portion of the lead screw 76 disposed within a lead screw housing 77. Specifically, the lead screw 76 rotates in response to drive from the electric actuator 72. The external threads of the lead screw 76 engage internal threads of an actuator nut 78 disposed on the lead screw 76.The actuator nut 78 is a single, integrally formed structure including a main body 80 and a retaining portion 82, with the retaining portion 82 extending from the main body 80. The main body 80 surrounds the lead screw 76, and at least a portion of the retaining portion 82 is disposed within a bracket opening 84 defined by a tilt bracket 86. The positioning of the retaining portion 82 within the bracket opening 84 prevents the actuator nut 78 from rotating, such that rotation of the lead screw 76 results in axial movement of the actuator nut 78 in the longitudinal direction of the lead screw 76. This axial movement of the actuator nut 78 pivots the tilt bracket 86 to drive tilt adjustment of the steering column 45.

[0023] The tilt adjustment assembly 52 disclosed herein includes features that assist the installation process of the tilt adjustment assembly 52 when mounted to the steering column 45 as disclosed herein. Furthermore, the tilt adjustment assembly 52 provides reliable operation with reduced noise, vibration, and shock.

[0024] In the Fig. 3 and Fig. 4, the tilt actuator assembly 52 is illustrated in an initial installation process step. As shown, the electric actuator 72, housing 74, lead screw 76, lead screw housing 77, and actuator nut 78 are already assembled. Similarly, the tilt bracket 86 is already operatively coupled to the shell of the steering column 45. In the illustrated installation process step, the tilt actuator assembly 52 is positioned such that the retaining portion 82 of the actuator nut 78 has not yet been inserted into the bracket opening 84 of the tilt bracket 86. At this stage, the tilt actuator assembly 52 is simply aligned in an insertive manner relative to the mounting structure 70 and the bracket opening 84 in preparation for alignment and assembly.

[0025] With reference to the Fig. 5 through 7, the tilt actuator assembly 52 includes at least one retention tab 88 extending radially outward from an outer surface of the retention portion 82 of the actuator nut 78. In the illustrated embodiment, three circumferentially spaced retention tabs 88 are provided, but it should be appreciated that the number of retention tabs 88 may be more or fewer than that shown and described herein. The bracket opening 84 defines at least one access slot 90. The number of access slot(s) 90 is equal to or greater than the number of retention tabs 88 provided on the retention portion 82 of the actuator nut 78. The access slots 90 extend completely through the tilt bracket 86 over the entire length of the bracket opening 84. The access slots 90 provide more space in the radial direction and are sized to allow the passage of the retention tabs 88 during installation.

[0026] Fig. 5 illustrates the tilt actuator assembly 52 prior to insertion of the retention tabs 88 into the access slots 90 of the tilt bracket 86. At this stage, the tilt actuator assembly 52 is rotated to align the retention tabs 88 with the access slots 90. Fig. 6 shows the retaining tabs 88 inserted through the access slots 90 and thus the retaining portion 82 of the actuator nut 78 in the bracket opening 84 of the tilt bracket 86. Fig. 7 is an enlarged view of the retaining tabs 88 after they have been fully inserted through the access slots 90. In this position, the actuator nut 78 can be withdrawn from the bracket opening 84 since the retaining tabs 88 are still aligned with the access slots 90. As shown in the Fig. 8-10, however, rotation of the tilt actuator assembly 52 cancels the alignment of the retention tabs 88 and the access slots 90. In this position, the actuator nut 78 cannot be withdrawn from the bracket opening 84 because the retention tabs 88 are no longer aligned with the access slots 90.

[0027] With continued reference to the Fig. 9 and Fig. 10, the tilt actuator assembly 52 is rotated to de-align the retention tabs 88 and the access slots 90 as described above, but it is difficult for an installer to estimate how far the assembly needs to be rotated to secure it to the mounting structure 70. Therefore, the tilt actuator assembly 52 described herein includes a position-lock feature that eliminates any uncertainty on the part of the installer.

[0028] In the Fig. 11 and Fig. 12 are a section of the fastening structure 70 ( Fig. 11) and the lead screw housing 77 ( Fig. 12). In particular, a structural extension 91 of the mounting structure 70 is shown in more detail. The structural extension 91 includes a tab 92 extending from one side of the structural extension. The tab 92 includes a mounting boss 94 extending from a substantially flat surface 96 of the tab 92. The mounting boss 94 forms the pivot axis during normal tilt loading operation. The tab 92 is embedded on the lead screw housing 77 to provide an additional backlash elimination function and ensure high load carrying during an impact event where the actuator resists the excessive loading from column collapse.The lateral positional deviation between the flat surface 96 of the nose 92 and the tilt bracket surface is compensated by the actuator nut moving laterally towards the opening of the tilt bracket during tilt actuations of the tilt bracket.

[0029] A first fastener-receiving hole 98 is located in the same plane as the base of the mounting boss 94. On the opposite side of the mounting boss is a second fastener-receiving hole 100, which, together with the first fastener-receiving hole 98, forms a pair of fastener-receiving holes. However, the flat surface 96 ends, and a step feature 102 extends at a substantially right angle from the flat surface 96. A second flat surface 104 extends at a right angle from the step feature 102 and includes the second fastener-receiving hole 100. Therefore, the pair of fastener-receiving holes 98, 100 have respective insertion positions offset by the step feature 102 included in the mounting structure 70.

[0030] The lead screw housing 77 includes a mounting recess or hole 106 sized to receive the mounting boss 94 extending from the mounting structure 70 and permits relative rotation. During installation, the tilt actuator assembly 52 is rotated until the step 108 of the lead screw housing contacts the step 102 of the mounting structure 70. Such positioning facilitates insertion of the mounting boss 94 into the mounting recess or hole 106 and reliably aligns a pair of fastener apertures 110 with the pair of fastener receiving bores 98, 100 of the mounting structure 70. The pair of fastener apertures 110 are sized to each receive a fastener 112 ( Fig. 13). The fasteners 112 do not permanently attach the lead screw housing 77 to the lug 92, but rather only contact the recessed surface of the lead screw housing's fastener pocket to maintain the housing fully engaged with the flat lug surface 96 during tilt actuation. The housing 77 moves relative to the fasteners 112.

[0031] Fig. 13 shows the tilt actuator assembly 52 in a fully installed state with respect to the mounting structure 70 and the steering column 45.

[0032] The embodiments disclosed herein enable faster and more reliable assembly and installation by allowing the operator to place the tilt actuator assembly 52 on the tilt bracket 86 and rotate it into its mounting position. Furthermore, the embodiments of the tilt actuator assembly 52 allow for the removal of several mounting hardware from the steering column assembly, resulting in cost savings.

Claims

[1] Steering column assembly (44) comprising: a shell (50) operatively coupled to a mounting structure (70); and a tilt actuator assembly (52) operatively coupled to the shell (50) and the mounting structure (70) to adjust a tilt position of the shell (50), the tilt actuator assembly (52) comprising: an electrical actuator (72); a lead screw (76) driven by the electric actuator (72); an actuator nut (78) that is displaced along the lead screw (76) during rotation of the lead screw (76), the actuator nut (78) having a main body (80) surrounding the lead screw (76) and a retaining portion (82) extending from the main body (80), the retaining portion (82) having a retaining tab (88) extending radially outward; and a tilt bracket (86) operatively coupled to the shell (50) and defining a bracket opening (84), the bracket opening (84) including an access slot (90) sized to receive the retention tab (88), the retention tab (88) preventing withdrawal of the actuator nut (78) from the bracket opening (84) upon full insertion through the access slot (90) and rotation of the actuator nut (78) to de-align the retention tab (88) and the access slot (90). [2] The steering column assembly (44) of claim 1, wherein the retaining tab (88) is one of a plurality of retaining tabs (88) and the access slot (90) is one of a plurality of access slots (90), the number of the plurality of retaining tabs (88) and the number of the plurality of access slots (90) being the same. [3] The steering column assembly (44) of claim 1, wherein the actuator nut (78) is a single, integrally formed structure. [4] The steering column assembly (44) of claim 1, further comprising a lead screw housing (77) defining a mounting recess or hole (106) sized to receive a mounting boss (94) extending from the mounting structure (70). [5] The steering column assembly (44) of claim 4, wherein the lead screw housing (77) defines a pair of fastener apertures (110) each sized to receive a fastener (112). [6] The steering column assembly (44) of claim 5, wherein the mounting structure (70) includes a pair of fastener receiving holes (98, 100) defined therein, the pair of fastener receiving holes (98, 100) being disposed on opposite sides of the mounting projection (94). [7] The steering column assembly (44) of claim 6, wherein the pair of fastener receiving holes (98, 100) have respective insertion locations offset by a step feature (102) included on the mounting structure (70). [8] A method of installing a tilt actuator assembly (52) into a steering system (40), the method comprising: aligning a plurality of retaining tabs (88) of an actuator nut (78) with a first side of a plurality of access slots (90) defined by a bracket opening (84) of a tilt bracket (86); Inserting the plurality of retaining tabs (88) through the plurality of access slots (90) until the plurality of retaining tabs (88) are located on a second side of the plurality of access slots (90); and Rotating the actuator nut (78) until the plurality of retaining tabs (88) are out of alignment with the plurality of access slots (90) to prevent withdrawal of the actuator nut (78) from the tilt bracket (86). [9] The method of claim 8, further comprising rotating a lead screw (76) and a lead screw housing (77), both operatively coupled to the actuator nut (78), to insert a mounting projection (94) extending from a mounting structure (70) into a mounting recess or hole (106) defined by the lead screw housing (77) to position the tilt actuator assembly (52) in a desired installation position.

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