Translational power adjustable steering column with absolute sensor rack and pinion

Abstract

An axially adjustable steering column assembly includes an upper sleeve. The steering column assembly also includes a lower sleeve, wherein the upper sleeve is received within and telescopingly adjustable therein, the lower sleeve defining a pair of slots extending in an axial direction along the lower sleeve. The steering column assembly also includes a column mount, wherein the lower sleeve translates and rotates relative to the column mount. The steering column assembly also includes a pair of bushings positioned within the pair of slots. The steering column assembly also includes a rack operatively connected to one of the pair of bushings, the rack being rotatable accordingly with the lower sleeve. The steering column assembly also includes a sensor operatively contacting the rack to detect the axial position of the axially adjustable steering column assembly.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Patent Application Serial No. 63 / 388,298, filed July 12, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments described herein relate to vehicle steering systems, and more specifically, to translational power-adjustable steering columns with absolute sensor racks and pinions. Background Technology

[0004] Vehicles (such as cars, trucks, SUVs, crossovers, minivans, boats, aircraft, ATVs, recreational vehicles, or other suitable vehicles) include a variety of steering system schemes, such as steer-by-wire and driver-interface steering. These steering system schemes typically include a steering column, which converts steering inputs into outputs that interact with steering linkages to ultimately turn the wheels (or other components) of the vehicle.

[0005] Some steering columns are axially adjustable between different positions. In the past, the function of axially adjustable steering columns was to provide flexibility in steering wheel positioning and to facilitate a more comfortable driving position for drivers of different sizes. However, there is now an opportunity to achieve greater extension and retraction, also known as retraction (i.e., when the steering wheel is not needed). For example, the steering wheel can be repositioned further away from the driver to allow him or her to do things other than operating the vehicle, such as working on a laptop computer when the vehicle is parked. Other examples include vehicles with autonomous driving capabilities, where the steering wheel can be retracted when the vehicle is in autonomous driving mode.

[0006] As the automotive industry increasingly favors steer-by-wire technology, there is a growing emphasis on redundancy in position sensing technology to ensure the position of comfort components in both functional and retractable modes. Therefore, some original equipment manufacturers (OEMs) may require direct, absolute sensing of the steering column's telescopic position, compared to previous reliance on encoders and Hall pulse analysis. Absolute position sensing requires sensors to actually read the position of the steering column's telescopic position. For an externally translating, internally telescopic column, the column assembly has two distinct interfaces that can move simultaneously during the retractable function. The first movement is the movement of the upper sleeve relative to the lower sleeve (i.e., a typical standard power-adjustable telescopic column), but this movement is also paired with a second translational interface between the lower sleeve and the column mount. Together, these two movements create a high retractable rate and a large retractable displacement in the vehicle, causing the steering wheel to move towards and into the dashboard.

[0007] Standard telescopic sensing systems with absolute position sensors involve a rack and pinion driven by the movement of the upper sheath. This rack runs along the absolute position sensor, driving a cogged wheel on the sensor. The rotational motion of the cogged wheel is then used to interpret the position of the upper sheath during its telescopic movement. This externally translating, internally telescopic column presents a challenge in how to use an absolute position sensor to sense the displacement of the lower sheath relative to the column mount. This is because the retraction movement only occurs in one plane (i.e., the forward / aft direction of the vehicle), while the lower sheath can also be vertically hinged during the rake function. This leads to a unique situation requiring special consideration of how the rack and pinion can interact with the absolute position sensor. The rack and pinion must be fixed in place on the column mount but must also be able to hinge with the tilting movement of the lower sheath. Summary of the Invention

[0008] According to one aspect of this disclosure, an axially adjustable steering column assembly includes an upper sheath. The steering column assembly also includes a lower sheath, wherein the upper sheath is received within and telescopingly adjustable therein, the lower sheath defining a pair of slots extending in an axial direction along the lower sheath. The steering column assembly also includes a column mount, wherein the lower sheath translates and rotates relative to the column mount. The steering column assembly also includes a pair of bushings positioned within the pair of slots. The steering column assembly also includes a rack operatively connected to one of the pair of bushings, the rack being rotatable accordingly with the lower sheath. The steering column assembly also includes a sensor operatively contacting the rack to detect the axial position of the axially adjustable steering column assembly.

[0009] According to another aspect of the invention, an axial position sensing system for a steering column assembly includes a column mount. The axial position sensing system also includes a column structure operatively connected to the column mount, the column structure being axially movable and rotatable relative to the column mount, the column structure defining a pair of slots extending along the axial direction of the column structure. The axial position sensing system also includes a pair of wedge bushings positioned within the pair of slots, the wedge bushings having at least one tapered surface configured to contact one or more walls defining the pair of slots. The axial position sensing system also includes a gear rack integrally formed with one of the pair of wedge bushings. The axial position sensing system further includes a sensor operatively contacting the gear rack to detect the axial position of the column structure.

[0010] These and other advantages and features will become more apparent from the following description taken in conjunction with the accompanying drawings. Attached Figure Description

[0011] The subject matter considered to be the invention is specifically pointed out and expressly claimed in the appended claims. 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:

[0012] Figure 1 A schematic diagram of a vehicle's steering system;

[0013] Figure 2 This is a front view of the steering column assembly of the vehicle's steering system in its first tilt position;

[0014] Figure 3 This is a front view of the steering column assembly in the second tilt position;

[0015] Figure 4 This is a front view of the steering column assembly in the axially retracted position;

[0016] Figure 5 This is a perspective view of the steering column assembly of the rack and pinion system; and

[0017] Figure 6 This is a perspective view of the steering column assembly, which is a gear and rack in contact with the absolute position sensor. Detailed Implementation

[0018] The following discussion pertains to various embodiments of this disclosure. While one or more of these embodiments may be described in more detail than others, the disclosed embodiments should not be construed as or otherwise used to limit the scope of this disclosure, including the claims. Furthermore, those skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is merely illustrative of that embodiment.

[0019] As described, vehicles (such as cars, trucks, SUVs, crossovers, minivans, boats, aircraft, ATVs, recreational vehicles, or other suitable vehicles) include a variety of steering system schemes, such as steer-by-wire and driver-interface steering. These steering system schemes typically include a steering column, which translates steering inputs into outputs that interact with steering linkages to ultimately turn the wheels (or other elements) of the vehicle. Some steering columns are axially adjustable between different positions. In the past, the function of axially adjustable steering columns was to provide flexibility in the position of the steering wheel and to provide a more comfortable driving position for drivers of different body types. However, there is now an opportunity to achieve greater extension and retraction, which can also be called retractable travel (i.e., when the steering wheel is not needed). For example, the steering wheel can be repositioned completely away from the driver to allow him or her to do things other than operating the vehicle, such as working on a laptop computer when the vehicle is parked. Other examples include vehicles with autonomous driving capabilities, in which case the steering wheel can be retracted when the vehicle is in autonomous driving mode.

[0020] Referring now to the accompanying drawings, various embodiments are shown and described herein, but are not limited thereto. The drawings illustrate embodiments of an axially adjustable steering column assembly with improved packaging and other operational advantages. Axial adjustability arises from the relative movement between two or more steering column portions (e.g., sleeves, brackets, rails, and / or the like) that allow axial movement between them, combined with the relative movement between multiple steering shaft portions that allow axial movement between them. Axial movement refers to movement caused by relative telescopic, sliding, or translational movement between components.

[0021] First refer to Figure 1 The present disclosure generally illustrates a vehicle 20. Vehicle 20 may include any suitable vehicle, such as an automobile, truck, SUV, minivan, crossover, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. While vehicle 20 may be a wheeled passenger vehicle used on roads, the principles of this disclosure can be applied to other vehicles, such as airplanes, tractors, boats, or other vehicles. Vehicle 20 may include a propulsion system 30, such as an ignition system, electronic systems, or a combination thereof.

[0022] The vehicle 20 further includes a steering system 40. The steering system 40 can be configured as a driver-interface steering system, an automatic steering system, or a system that allows both driver-interface and automatic steering. The steering system 40 may include an input device 42, such as a steering wheel, through which a driver can mechanically provide 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, a steer-by-wire component, or any feature conventionally located opposite the input device 42.

[0023] The steering column 45 may include at least two axially adjustable portions, such as an upper sheath 48 and a lower sheath 50 that are axially adjustable relative to each other. In some embodiments, the at least two axially adjustable portions may further include at least one third portion 49 disposed between the upper sheath 48 and the lower sheath 50. It should be understood that other structural features of the steering column 45 may be part of the upper sheath 48 and the lower sheath 50, such as brackets, rails, other devices, or combinations thereof.

[0024] The steering column 45 is movable within a position range from fully extended to fully retracted. In the fully extended position, the upper sheath 48 and lower sheath 50 move axially such that the input device 42 is located near the operator of the vehicle. In the retracted position, the upper sheath 48 and lower sheath 50 move axially such that the input device 42 is located further away from the operator of the vehicle compared to the extended position. In some embodiments, the retracted position may correspond to retracting the input device 42. For example, it may be advantageous to place the input device 42 in the retracted position during autonomous driving. In operation, the axial movement of the upper sheath 48 and lower sheath 50 can be achieved by manual movement by the operator or electromechanically by a telescopic actuator. This axial movement is adjustable between the extended position, the retracted position, and any intermediate position.

[0025] Steering gear assembly 54 can be connected to output assembly 46 via steering gear input shaft 56. Steering gear assembly 54 can be configured as a rack and pinion, a recirculating ball steering gear, or any other type of steering gear associated with automatic steering systems and driver interface steering systems. Steering gear assembly 54 can then be connected to driving axle 58 via output shaft 60. Output shaft 60 may include a pitman arm and sector gears and / or various conventional components. Output shaft 60 is operatively connected to steering gear assembly 54 such that rotation of steering gear input shaft 56 causes responsive movement of output shaft 60, which in turn causes driving axle to rotate wheel 62. It should be understood that the steering components described herein can be part of a steer-by-wire system or a system comprising direct mechanical linkages across the component span.

[0026] Now refer to Figure 2 and Figure 3 The steering column assembly 44 is illustrated in more detail below. An upper sleeve 48 is shown protruding from a lower sleeve 50. The lower sleeve 50 is operatively connected to and axially translatable relative to the column mount 70. The column mount 70 is fixed relative to the vehicle structure to mount the steering column assembly 44 onto the vehicle 20. The upper sleeve 48 is axially adjustable relative to the lower sleeve 50 within a first range of axial positions, which may be referred to as the "comfort range." The comfort range is the range of axial positions useful for manual driving during operation of the vehicle for operators of different body types. The axial movement of the upper sleeve 48 relative to the lower sleeve 50 is accomplished in a telescoping manner due to the movement of the upper sleeve 48 within the lower sleeve 50. The comfort range includes the entire comfort range and a possible portion of the retracted range. The lower sleeve 50 is axially adjustable relative to the column mount 70 within a second range of axial positions, which may be referred to as the "retracted range." The retracted range, when compared to the comfort range, is the range that allows the entire steering column assembly 44 to move further away from the operator's axial position. In some embodiments, the fully retracted position is a stowed position that allows the steering input device (e.g., steering wheel) to be flush with the dashboard, firewall, or other vehicle structure. The axial movement of the lower sheath 50 relative to the pillar mount 70 is translational, as the overall upper and lower sheaths move together near the pillar mount 70. Figure 4 The diagram illustrates the axial retraction adjustability of the steering column assembly 44, wherein the first portion 48 is fully retracted into the second portion 50, which is fully telescopically translatable relative to the column mount bracket 70.

[0027] The steering column assembly 44 includes a first actuator 72, which may be referred to as a comfort actuator. The first actuator 72 is operatively connected to the upper sleeve 48 to control telescopic movement of the upper sleeve 48 relative to the lower sleeve 50 within a first range of axial positions. In the illustrated embodiment, the first actuator 72 is mounted to a specific portion of the steering column assembly 44, but other mounting locations are also contemplated.

[0028] The steering column assembly 44 also includes a second actuator 74, which may be referred to as a retraction actuator. The second actuator 74 is operatively connected to the lower sheath 50 to control translational movement of the lower sheath 50 relative to the column mount bracket 70 within a second range of axial positions. In the illustrated embodiment, the second actuator 74 is mounted to a specific portion of the steering column assembly 44, but other mounting locations are also contemplated.

[0029] Both the first actuator 72 and the second actuator 74 are located near the front position of the steering column assembly 44 to accommodate axial movement during retraction. Both actuators 72 and 74 are responsible for the full retraction movement of the column; however, during comfort adjustment within a first range of axial adjustment positions, only the first actuator 72 operates.

[0030] Continue to refer to Figure 2 and Figure 3 In addition to the axial adjustability of the steering column assembly 44, the steering column assembly 44 is adjustable in the tilt direction, which allows the entire steering column assembly 44 to be angularly hinged about the pivot of the lower sleeve 50 about which it rotates. This effectively allows the steering input device 42 to move up or down according to the user's preference. The tilt actuator assembly 76 is mounted on the lower sleeve 50. As shown, the lower sleeve 50, and therefore the steering column assembly 44, is in various tilt positions (including the first tilt position). Figure 2 ) and the lowered second tilt position ( Figure 3 It can move between )). It should be understood that different ranges of tilt adjustability will be used for different steering column applications.

[0031] like Figure 5 As shown, the embodiments disclosed herein include tapered track grooves 80 defined within a lower sheath 50, forming a pair of tracks. Specifically, a first track is formed on one side of the lower sheath 50 via one of the grooves, while a second track is formed on a second side of the lower sheath 50. At least one sliding wedge bushing 84 is disposed within each tapered track groove 80. The sliding wedge bushing 84 has a tapered shape that substantially corresponds to the angular direction of the tapered track groove 80. The tapered track groove 80 in each component serves as a receiving interface for de-lashing the sliding wedge bushing 84 and provides guidance for translation of the lower sheath 50 relative to the post mount bracket 70 during retraction operations.

[0032] A rack 90 is connected to one or more wedge bushings 84 and engages with an absolute position sensor 92. The rack 90 includes a surface with a plurality of teeth 91 formed over at least a portion of the length of the surface. Each rack 90 is connected to one or more wedge bushings 84, or is integrally formed with a wedge bushing 84 to form a single unitary component. The rack 90 and wedge bushings 84 are operatively connected to a post mount 70. Therefore, during translation of the lower sheath 50, the rack 90 and wedge bushings 84 remain stationary relative to the lower sheath 50. However, the rack 90 and wedge bushings 84 are pivotally connected to the post mount 70. Thus, during articulation of the lower sheath 50, the wedge bushings 84 remain aligned with their respective tracks of the lower sheath 50 to allow guided translation of the lower sheath 50.

[0033] For the translation function of the retracting motion, the absolute position sensor 92 is mounted on the lower sheath 50. Figure 6 When the lower sleeve 50 is at its tilt hinge, the wedge bushing 84 follows this hinge, keeping the rack 90 aligned with the absolute position sensor 92 fixed to the lower sleeve 50. However, when the steering column assembly 44 is moved to the retracted position, as the lower sleeve 50 translates relative to the column mount 70 and the rack 90, the wedge bushing 84—positionally fixed to the lower sleeve 50—remains in place with the column mount 70.

[0034] refer to Figure 6 When the lower sheath 50 is translated, multiple teeth 91 of the rack 90 run along the cogged teeth 93 of the absolute position sensor 92, providing an accurate description of the axial position of the steering column assembly 44 without skewing during different tilt positions of the lower sheath 50.

[0035] Although the invention has been described in detail with reference to only a limited number of embodiments, it is readily understood that the invention is not limited to these disclosed embodiments. Rather, the invention can be modified to include any number of variations, alterations, substitutions, or equivalent arrangements, though not previously described, that are commensurate with the concept and scope of the invention. Furthermore, while various embodiments of the invention have been described, it should be understood that aspects of the invention may include only some of the described embodiments. Moreover, any feature, element, component, or advantage of any embodiment can be used in any other embodiment. Therefore, the invention should not be considered as limited by the foregoing description.

Claims

1. An axially adjustable steering column assembly, comprising: Top cover; A lower sheath, wherein the upper sheath is housed within the lower sheath and is telescopically adjustable therein, the lower sheath defining a pair of slots extending in the axial direction of the lower sheath; A column mounting bracket, wherein the lower sheath translates and rotates relative to the column mounting bracket; The paired bushings are positioned within the paired slots; A gear rack, operably connected to one of the paired bushings, the gear rack being correspondingly rotatable with the lower bushing; and A sensor, operably in contact with the gear rack, detects the axial position of the axially adjustable steering column assembly.

2. The axially adjustable column assembly of claim 1 wherein, Each of the paired bushings has at least one tapered surface configured to contact one or more walls defining the paired grooves.

3. The axially adjustable steering column assembly according to claim 2, wherein, One or more walls of the paired grooves are tapered to correspond to at least one tapered surface of the paired bushings.

4. The axially adjustable steering column assembly according to claim 1, wherein, The gear rack is integrally formed with one of the paired bushings.

5. The axially adjustable steering column assembly according to claim 4, wherein, The gear rack is operably connected to the column mounting bracket and is rotatable relative to the column mounting bracket.

6. The axially adjustable steering column assembly according to claim 1, wherein, The gear rack includes multiple rack teeth, and the sensor includes an absolute position sensor having a gear that contacts the multiple rack teeth.

7. The axially adjustable steering column assembly according to claim 6, wherein, The gear is one of a plurality of gears in the absolute position sensor.

8. The axially adjustable steering column assembly according to claim 1, wherein, The gear rack does not translate relative to the column mounting bracket.

9. The axially adjustable steering column assembly according to claim 1, further comprising: A first actuator is operatively connected to the upper sheath to control the axial adjustment of the upper sheath relative to the lower sheath; A second actuator is operatively connected to the lower sheath to control the axial adjustment of the lower sheath relative to the column mount bracket; as well as A tilt actuator is operatively connected to the lower sheath to control the tilt adjustment of the lower sheath.

10. An axial position sensing system for a steering column assembly, comprising: Column mounting bracket; A column structure operably connected to the column mounting bracket, the column structure being movable in an axial direction relative to the column mounting bracket and being rotatable relative to the column mounting bracket, the column structure defining a pair of slots extending in the axial direction of the column structure; A pair of wedge bushings are positioned within the pair of slots, the wedge bushings having at least one tapered surface configured to contact one or more walls defining the pair of slots; The gear rack is integrally formed with one of the paired wedge bushings; as well as A sensor is operatively in contact with the gear rack to detect the axial position of the column structure.

11. The axial position sensing system according to claim 10, wherein, One or more walls of the paired grooves are tapered to correspond to at least one tapered surface of the paired wedge bushings.

12. The axial position sensing system according to claim 10, wherein, The gear rack is operably connected to the column mounting bracket and is rotatable relative to the column mounting bracket.

13. The axial position sensing system according to claim 10, wherein, The gear rack includes multiple rack teeth, and the sensor includes an absolute position sensor having a gear that contacts the multiple rack teeth.

14. The axial position sensing system according to claim 13, wherein, The gear is one of a plurality of gears in the absolute position sensor.

15. The axial position sensing system according to claim 10, wherein, The gear rack does not translate relative to the column mounting bracket.

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