Cyclic ball-type track telescoping interface assembly for steering column

Abstract

The axially adjustable steering column assembly includes a first support structure. The axially adjustable steering column assembly also includes a second support structure, wherein the first support structure is axially adjustable relative to the second support structure in a telescopic manner. The axially adjustable steering column assembly also includes a plurality of telescopic interface assemblies disposed between the first and second support structures. Each telescopic interface assembly includes a track formed in at least one of the first and second support structures. Each telescopic interface assembly also includes a plurality of metal balls disposed in the track to provide a rolling interface therebetween during axial adjustment between the first and second support structures.

Description

Technical Field

[0001] The embodiments described herein relate to vehicle steering systems, and more specifically, to steering columns having a retractable ball bearing track interface assembly. Background Technology

[0002] Vehicles (such as cars, trucks, SUVs, crossovers, minivans, boats, aircraft, ATVs, recreational vehicles, or other suitable means of transport) include various 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, ultimately causing the wheels (or other components) to turn the vehicle. Some steering columns are axially adjustable between different positions to provide flexibility in handwheel positioning and a more comfortable driving position for drivers of different sizes. More recently, the steering column can be axially adjusted to move to a significantly retracted position, which can also be referred to as the "stowed" position.

[0003] Steering column assemblies typically have stringent requirements for natural frequency, stiffness, and telescope effort. A common telescope interface between the steering column jackets is a "tube-tube" with an injected "telescope sleeve." The design of a tube-tube with a telescope sleeve is difficult to meet performance specifications for natural frequency, stiffness, and telescope effort. Injecting plastic under high pressure increases stiffness but worsens the telescope effort (and vice versa). Because the coefficients of thermal expansion of the plastic bushing, the plastic injection material, and the steel jacket differ, the telescope effort is further affected at different temperatures. If performance specifications are sufficiently stringent, different, more expensive columns may need to be designed. Summary of the Invention

[0004] According to one aspect of the invention, an axially adjustable steering column assembly includes a first support structure. The axially adjustable steering column assembly further includes a second support structure, wherein the first support structure is axially adjustable relative to the second support structure in a telescopic manner. The axially adjustable steering column assembly also includes a plurality of telescopic interface assemblies disposed between the first and second support structures. Each telescopic interface assembly includes a track formed in at least one of the first and second support structures. Each telescopic interface assembly also includes a plurality of metal balls disposed in the track to provide a rolling interface therebetween during axial adjustment between the first and second support structures.

[0005] According to another aspect of the invention, a recirculating ball-type track telescopic interface assembly for a steering column includes a first component formed of steel. The recirculating ball-type track telescopic interface assembly also includes a second component formed of steel, wherein the first component is axially adjustable relative to the second component in a telescopic manner. The recirculating ball-type track telescopic interface assembly also includes a closed path track formed in at least one of the first and second components. The recirculating ball-type track telescopic interface assembly also includes a plurality of steel balls disposed in the track to provide a rolling interface therebetween during axial adjustment between the first and second components.

[0006] According to another aspect of the invention, a method for assembling an axially adjustable steering column assembly is provided. The method includes forming a track as a recessed portion within one of an upper and a lower sheath. The method further includes mounting a plurality of steel balls within the track. The method also includes inserting the upper sheath into a hole defined by the lower sheath for telescoping relative to the lower sheath.

[0007] These advantages and features, along with others, will become more apparent from the following description taken in conjunction with the accompanying drawings. Attached Figure Description

[0008] The subject matter considered to be the present invention is specifically pointed out and expressly claimed in the claims at the end 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, wherein:

[0009] Figure 1 A steering system for a vehicle is schematically shown;

[0010] Figure 2 It is a side view of part of the steering column of the steering system, featuring a recirculating ball-type track telescopic interface component;

[0011] Figure 3 It is a side view of a part of the steering column of the steering system, with a circulating ball-type track telescopic interface assembly equipped with ball bearings.

[0012] Figure 4 This is a front cross-sectional view of a part of a recirculating ball-bearing track telescopic interface assembly; and

[0013] Figure 5 This is a 3D view of a retractable ball bearing track interface component. Detailed Implementation

[0014] The following discussion pertains to various embodiments of the invention. 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 the invention, including the claims. Furthermore, those skilled in the art will understand that the following description has broad application, and any discussion of any embodiment is merely illustrative of that embodiment and does not imply that the scope of the invention, including the claims, is limited to that embodiment.

[0015] As described above, vehicles (e.g., cars, trucks, SUVs, crossovers, minivans, boats, aircraft, ATVs, recreational vehicles, or other suitable vehicles) include various steering system schemes (e.g., steer-by-wire and driver-interface steering). These steering system schemes typically include a steering column for translating steering inputs into outputs that interact with steering linkages, ultimately causing the wheels (or other elements) to move the vehicle. Some steering columns are axially adjustable between different positions. Historically, the sole function of an axially adjustable steering column was to provide flexibility in the position of the handwheel and a more comfortable driving position for drivers of different sizes. However, there is now an opportunity to achieve greater telescopic travel, also known as retractable travel (i.e., when the handwheel is not needed). For example, the handwheel can be repositioned completely away from the driver to allow the driver to do things other than operating the vehicle, such as working on a laptop while the vehicle is parked. Other embodiments include vehicles with autonomous driving capabilities, such that the handwheel can be retracted when the vehicle is in autonomous driving mode. The embodiments disclosed herein can be used with any steering column designed for telescopic axial adjustment, whether or not it has retractable capability.

[0016] Referring now to the accompanying drawings, in which various embodiments are shown and described, but not limited thereto, the steering column assembly has axial energy adjustability resulting from the relative movement between two or more steering column portions (also referred to herein as sheaths) that allow axial movement therebetween. While sheaths are discussed herein as “parts” that allow axial movement of the steering column assembly, it should be understood that any structure that allows axial movement therebetween due to relative telescopic, sliding, or translational movements can be used as said part. Other embodiments include brackets, guide rails, etc. The term “part” as used herein may also be used interchangeably as “support structure,” such as “external support structure” and “internal support structure.”

[0017] First refer to Figure 1The present invention generally illustrates a vehicle 20 according to the principles of the invention. Vehicle 20 may include any suitable vehicle, such as a car, 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 the invention can be applied to other vehicles, such as airplanes, tractors, boats, or other suitable vehicles. Vehicle 20 may include a propulsion system 30, such as an ignition system, an electronic system, or a combination thereof.

[0018] In some embodiments, vehicle 20 may also include a steering system 40. Steering system 40 may be configured as a driver interface steering system, an autonomous driving system, or a system that allows both driver interface and automatic steering. The steering system 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. Steering column assembly 44 includes a steering column 45 extending along an axis from input device 42 to output assembly 46. 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 input device 42.

[0019] The steering column 45 may include at least two axially adjustable portions, such as a first sleeve 48 and a second sleeve 50 that are axially adjustable relative to each other. It is conceivable that the entire steering column 45 may include more sleeves 48 and 50 than illustrated and described. The first portion 48 and the second portion 50 may be constructed as sleeves, referred to as the upper sleeve 48 and the lower sleeve 50, respectively (or as the first support structure and the second support structure, respectively). It should be understood that other structural features of the steering column 45 may include brackets, guide rails, other devices, or combinations thereof.

[0020] The steering column 45 is movable between an extended position and a retracted position. In the extended position, the first portion 48 is axially moved relative to the second portion 50, such that the input device 42 is located near the vehicle operator. In the retracted position, the first portion 48 is axially moved relative to the second portion 50, such that the input device 42 is located further away from the vehicle operator compared to the extended position. In some embodiments, the retracted position may correspond to the retracted 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 between the first portion 48 and the second portion 50 can be achieved by manual movement by the operator or by electromechanical movement of a telescopic actuator. This axial movement is adjustable between the extended position, the retracted position, and any intermediate position.

[0021] The steering gear assembly 54 can be connected to the output assembly 46 via the steering gear input shaft 56. The steering gear assembly 54 can be configured as a rack and pinion, a recirculating ball steering system, or any other type of steering gear associated with an automatic and driver-interface steering system. The steering gear assembly 54 includes an output component that interacts with a rack or other component that controls the movement and position of the road wheel 62. This is a case of mechanical connection throughout the steering column; however, it should be understood that the output assembly 46 is part of a steer-by-wire system that is electrically connected to the steering gear assembly 54 to control the wheel 62.

[0022] Now for reference Figure 2 and Figure 3 A portion of the steering column assembly 44 is shown in more detail. Specifically, the first sleeve 48 and the second sleeve 50 are shown relative to each other. As described herein, the steering column 45 is axially adjustable to move between an extended position and a retracted position. In some embodiments, the axial adjustment can be performed manually by an operator or electromechanically by an actuator. In the illustrated embodiment, sleeves 48, 50 extend longitudinally about a common axis X, and during axial adjustment of the steering column 45, the first sleeve 48 radially surrounds the second sleeve 50. However, although the first sleeve 48 surrounds the second sleeve 50, it should be understood that the opposite configuration may be used in other embodiments.

[0023] like Figure 2As shown, a recirculating ball-type track telescopic interface assembly 100 is illustrated. During axial telescopic adjustment of the steering column 45, the telescopic interface assembly 100 provides a rolling interface between the upper sheath 48 and the lower sheath 50. The telescopic interface assembly 100 is located at an axial position of the steering column 45 that covers the full range of a specified axial travel of the steering column 45 (i.e., fully extended to fully retracted). As will be understood from the description herein, the telescopic interface assembly 100 may also be referred to as a ball-type loop.

[0024] The telescopic interface assembly 100 includes at least one track 102 configured to hold a plurality of balls 110. Figure 2 The diagram shows that at least one orbital 102 is empty, while... Figure 3 A ball bearing 110 is installed in the center. In the illustrated embodiment, at least a portion of two tracks 102 are shown, with a third track (not shown) located on the opposite side of the steering column 45. In such an embodiment, the tracks 102 are circumferentially spaced from each other. In some embodiments, the tracks may be equidistant (e.g., 120 degrees from centerline to centerline), while other embodiments may have different circumferential spacing. Furthermore, in some embodiments, the number of tracks 102 may vary. Regardless of the number of tracks 102 or the spacing between them, each track 102 essentially forms a closed path, such as an ellipse, a circle, etc. Figure 2 and Figure 3 The diagram shows an ellipse. In some embodiments, the balls 110 of each track 102 travel in a common direction (e.g., clockwise or counterclockwise), while in other embodiments, the balls 110 of one track 102 travel in a direction different from at least one other track 102. The load characteristics of the ball circuit can determine the direction of travel for each track 102.

[0025] Track 102 can be formed in the upper sheath 48, the lower sheath 50, or a combination of these sheaths. For example, the upper sheath 48 can have a radially outer surface 104 in which a recessed track portion is formed. Alternatively, the upper sheath 48 can have a radially inner surface 106 in which a recessed track portion is formed. As another alternative, both the radially outer surface 104 of the lower sheath 50 and the radially inner surface 106 of the upper sheath 48 can have recessed portions, which combine to form track 102. Track 102 can be formed in the sheaths 48 and 50 during the stamping stage of the process. By integrating track 102 into the sheaths 48 and 50 during stamping, the need for subsequent process steps or additional telescopic interface component parts is avoided, minimizing costs and reducing the number of parts. While stamping is one embodiment of a manufacturing method for forming track 102 into the first and / or second sheaths, other manufacturing methods are also contemplated. For example, track 102 can be machined into the surface. Other methods besides those explicitly disclosed herein may also be suitable.

[0026] The multiple balls 110 disposed in the track 102 are formed of metal (e.g., steel), as are the upper sheath 48 and lower sheath 50. Therefore, the friction associated with the rolling contact interface between the balls 110 and the sheaths 48, 50 is lower compared to a cylindrical telescoping interface comprising components formed of different materials. This low friction ensures that maintaining a small telescoping effect associated with the axial adjustment of the column is feasible for the operator or during automatic adjustment. Furthermore, the interface components (i.e., the sheaths 48, 50 and the balls 110) have similar or identical coefficients of thermal expansion because they are all formed of metal (e.g., steel). This further ensures a small telescoping effect that would otherwise be affected and inconsistent due to thermal effects. Due to the low friction and rolling characteristics of the interface, the radial interference between the balls 110 and the sheaths 48, 50 can be high, which improves the natural frequency and increases the overall stiffness of the steering column 45.

[0027] In some embodiments, the sleeves 48, 50 are primarily formed of a non-metallic material (e.g., plastic). However, the metallic (e.g., steel) interface between the ball 110 and the sleeve surface is maintained by a metal insert strategically positioned along the surface of the sleeves 48, 50. In other words, in such embodiments, the track 102 is formed of a metal insert.

[0028] Now for reference Figure 4 and Figure 5The diagram shows an enlarged view of a portion of the telescopic interface assembly 100. As shown, a ball bearing 110 is disposed within a track 102 and located between an upper sheath 48 and a lower sheath 50. Along a first portion 120 of the track 102, the ball bearing 110 is considered "loaded," which is defined as the position where the ball bearing 110 is positioned to contact the two sheaths 48, 50. Along a second portion 130 of the track 102... Figure 5 The ball 110 is considered "unloaded," which is defined as resulting in a radial clearance 140 between the ball and one of the bushings 48 or 50 (e.g., Figure 4 The position of the ball 110 is determined by the gap 48 between the upper sheath and the lower sheath (or conversely, the gap 50 between the upper and lower sheaths). The difference in radial position is based on the difference in radial position between the first portion 120 and the second portion 130 of the track 102. (See again...) Figure 2 and Figure 3 The first portion 120 of track 102 corresponds to one of the straight segments of track 102, while the second portion 130 of track corresponds to another straight segment 132 of track and the curved end 134 of track 102. In other words, the ball 110 contacts the two sleeves 48, 50 along the straight segment referred to as the first portion 120. The ball maintains a gap with one of the sleeves 48 or 50 along the other straight segment 132 and the curved end 134, which are collectively denoted by the numeral 130. However, in some embodiments, the ball 110 contacts all or part of the curved end 134 with both sleeves 48, 50.

[0029] The embodiments disclosed herein provide upper and lower sheaths 48 and 50 of metal (e.g., steel) with metal balls 110 therebetween, thereby providing a sliding interface for the telescopic adjustability of the steering column 45. It should be understood that the sliding interface discussed herein relates to a support structure surrounding the steering shaft assembly. The steering shaft assembly is the part of the system that transmits torque to achieve steering control, and the support structure surrounds this torque-transmitting part. The circulating ball path (i.e., the track 102 and the balls 110) of the telescopic interface assembly 100 allows the "loaded" balls to support the sheath interface while providing low friction and high stiffness.

[0030] The embodiments disclosed herein eliminate the need for a dedicated ball retaining component located between the first portion 48 and the second portion 50. For example, many existing components in steering columns that facilitate relative translation of the bushing or support structure require bushings, cages, or sleeves to retain the metal balls 110. Such components increase the number of parts and cost of the assembly. The assembly described herein does not include such a ball retaining component. Therefore, the embodiments disclosed herein advantageously reduce costs by providing the track 102 directly in or on the surfaces of the first portion 48 and / or the second portion 50.

[0031] 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. Instead, modifications can be made to the invention to incorporate any number of variations, alterations, substitutions, or equivalent arrangements not previously described but consistent with the spirit 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 to the foregoing description.

Claims

1. An axially adjustable steering column assembly, comprising: First supporting structure; The second support structure, wherein the first support structure is axially adjustable relative to the second support structure in a telescopic manner; and Multiple retractable interface components are disposed between the first support structure and the second support structure, each of the retractable interface components comprising: The track is formed in at least one of the first support structure and the second support structure; and Multiple metal balls are disposed in the track to provide a rolling interface between the first support structure and the second support structure during axial adjustment between the first support structure and the second support structure; Each of the telescopic interface components comprises a track including a first straight segment, a second straight segment, and a pair of curved end segments to form a closed path for the circulation of the ball. The surfaces of the first straight segment and the second straight segment have different radial positions to define different radial positions for the ball at different locations along the track. When the ball is located within the first straight segment, it contacts the first support structure and the second support structure. When the ball is located within the second straight segment, a radial gap is defined between the ball and one of the first and second support structures.

2. The axially adjustable steering column assembly according to claim 1, wherein, Both the first support structure and the second support structure are made of metal.

3. The axially adjustable column assembly of claim 2 wherein, The first support structure, the second support structure, and the plurality of metal balls are all made of steel.

4. The axially adjustable column assembly of claim 1, wherein, Both the first support structure and the second support structure are made of plastic and have corresponding metal inserts positioned to contact the plurality of metal balls.

5. The axially adjustable column assembly of claim 1, wherein, The track is formed as a recessed portion of the radial inner surface of the first support structure.

6. The axially adjustable column assembly of claim 1, wherein, The track is formed as a recessed portion of the radial outer surface of the second support structure.

7. The axially adjustable column assembly of claim 1, wherein, The track is formed as a combination of a recessed portion on the radial inner surface of the first support structure and a recessed portion on the radial outer surface of the second support structure.

8. The axially adjustable column assembly of claim 1, wherein, The plurality of scalable interface components consist of at least three scalable components.

9. The axially adjustable column assembly of claim 8, wherein, The at least three telescopic components are circumferentially spaced apart around the first support structure.

10. The axially adjustable column assembly of claim 8 wherein, The at least three telescopic components are circumferentially spaced apart around the first support structure.

11. The axially adjustable column assembly of claim 1, wherein, The ball contacts the first support structure and the second support structure along at least a portion of the curved end segment.

12. A circulating ball-type track telescopic interface assembly for a steering column, comprising: The first component is made of steel; The second component is made of steel, wherein the first component is axially adjustable relative to the second component in a telescopic manner; A closed path track is formed in at least one of the first component and the second component; and Multiple steel balls are arranged in the track to provide a rolling interface between the first component and the second component during axial adjustment between the first component and the second component; The track includes a first straight segment, a second straight segment, and a pair of curved end segments for the circulation of the balls; The surfaces of the first and second straight segments have different radial positions to define different radial positions for the ball at different locations along the track. When located within the first straight segment, the ball contacts both the first and second components. When located within the second straight segment, a radial gap is defined between the ball and one of the first and second components. Wherein, no bushing, retainer or sleeve is provided between the first component and the second component.

13. The rolling ball track telescoping interface assembly of claim 12, wherein, The track is formed as a recessed portion of at least one of the first component and the second component.

14. A method for assembling an axially adjustable steering column assembly, the method comprising: A track is formed as a recessed portion within one of the upper and lower sheaths; Multiple steel ball bearings are installed inside the track; as well as The upper sheath is inserted into the hole defined by the lower sheath to perform telescopic movement relative to the lower sheath; The track formed as a recessed portion within one of the upper and lower sheaths includes: A first straight segment, a second straight segment, and a pair of curved end segments are formed in the track, wherein the surfaces of the first straight segment and the second straight segment have different radial positions to define different radial positions for the steel ball at different locations along the track, wherein when located in the first straight segment, the steel ball contacts the upper sheath and the lower sheath, and wherein when located in the second straight segment, a radial gap is defined between the steel ball and one of the upper sheath and the lower sheath.

15. The method of claim 14, wherein, Forming the track includes stamping the recessed portion into the upper sheath and / or the lower sheath.

16. The method of claim 14, wherein, Forming the track includes attaching a metal insert to the upper sheath and / or the lower sheath.

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