Link system

Abstract

Steering system (20), comprising: a steering gear; a frame (50) having a frame surface; and a bushing (52) having a bushing surface (56) in operative contact with the frame surface and the steering gear, the bushing surface (56) or the frame surface being textured to form a friction surface; wherein the textured surface, be it the frame surface or the bushing surface (56), is textured with a laser; wherein the frame (50) is formed from a first material having a first hardness; wherein the bushing (52) is formed from a second material having a second hardness different from the first hardness; and wherein the component having the greater hardness comprises the textured surface.

Description

FIELD OF THE INVENTION

[0001] This disclosure relates to a laser-textured friction surface for interface-forming components. BACKGROUND

[0002] A vehicle, such as a car, truck, sport utility vehicle, crossover, minivan, watercraft, aircraft, off-road vehicle, recreational vehicle, or other suitable vehicle, has various steering systems, such as steer-by-wire (SbW) and driver interface steering. Often, the various steering schemes include an electric power steering (EPS) system, which includes components such as a steering wheel, column, rack and pinion, electric motor actuator, etc. The EPS assists the driver in steering the vehicle by providing required assist torque and feedback.

[0003] Certain rack-and-pinion EPS systems may experience problems when the steering gear moves relative to the frame to which the steering gear is mounted due to the smooth surface of the mounting bushing. The extreme loading of some vehicles can overcome the clamping force of some mounts, particularly during off-road driving or extreme maneuvers. This is just one example of an assembly that could slip relative to its mounting surface. The embodiments disclosed herein address this issue.

[0004] GB 2 279 712 A discloses a vibration damping arrangement provided in a seatbelt tensioning device. The seatbelt tensioning device is attached to a base via a first and a second cylindrical component. The mutually facing surfaces of the first and second components are in frictional contact via a flange assembly arranged between them, wherein one of the surfaces may be textured. Further prior art is known from DE 20 2014 103 932 U1, DE 10 2017 215 483 A1, and DE 10 2011 114 816 B4. SUMMARY

[0005] The object of the invention is to provide an improved steering system.

[0006] To achieve this object, a steering system having the features of claim 1 is provided. Advantageous embodiments of the invention can be found in the dependent claims, the description, and the drawings.

[0007] A friction assembly for assembled components includes a first component having a first interface. The friction assembly also includes a second component having a second interface, wherein the first interface and the second interface are in contact in an assembled state. One of the first and second interfaces is textured to form a friction surface.

[0008] According to one aspect of the disclosure, a steering system includes a steering gear. The steering system also includes a frame having a frame surface. The steering system further includes a bushing having a bushing surface in operative contact with the frame surface and the steering gear, wherein the bushing surface or the frame surface is textured to form a friction surface, wherein the textured surface, whether the frame surface or the bushing surface, is textured with a laser. The frame is formed from a first material having a first hardness. The bushing is formed from a second material having a second hardness. The component having the greater hardness comprises the textured surface.

[0009] A method of manufacturing an assembly with interfacing components includes comparing a first hardness of a first material of a first component with a second hardness of a second material of a second component. The method also includes determining which of the first and second materials is a harder material. The method further includes texturing the harder material with a laser to form a friction surface. The method further includes assembling the first and second components, wherein the friction surface is an interface between the first and second components.

[0010] These and other aspects of the present disclosure are disclosed in the following detailed description of the embodiments, the appended claims, and the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, as is customary, the various features of the drawings are not to scale. Rather, the dimensions of the various features have been arbitrarily expanded or reduced for the sake of clarity. Fig. 1 shows schematically a steering system with a steering gear; Fig. 2 is a perspective view of a portion of a steering rack assembly; and Fig. 3 is a perspective view of a laser textured bushing surface. DETAILED DESCRIPTION

[0012] The following discussion relates to various embodiments of the disclosure. The embodiments disclosed herein should not be construed or otherwise used as limiting the scope of the disclosure, including the claims. Furthermore, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is intended to be exemplary of that embodiment only and does not imply that the scope of the disclosure, including the claims, is limited to that embodiment.

[0013] The present invention may be incorporated into any suitable vehicle, such as a car, truck, sport utility vehicle, minivan, crossover, other passenger vehicle, suitable commercial vehicle, or other suitable vehicle. Furthermore, the principles of the present disclosure may also be applied to other vehicles, such as aircraft, boats, trains, drones, or other suitable vehicles. Furthermore, the present invention may be integrated into various steering system schemes and electric power steering (EPS) systems, including steer-by-wire systems.

[0014] In Fig. 1, a power steering system 20 is generally illustrated. The power steering system 20 may be configured as a driver interface steering system, as an autonomous driving system, or as a system that enables both a driver interface and autonomous or semi-autonomous steering. The steering system may include an input device 22, such as a steering wheel or other HWA, where a driver can mechanically provide a steering input by turning the steering wheel. An airbag device 24 may be located on or near the input device 22. A steering column 26 extends along an axis from the input device 22 to an output assembly 28. The steering column 26 may include at least two axially adjustable parts, e.g., a first portion 30 and a second portion 32, which are axially adjustable relative to one another.The output assembly 28 may include a pinion shaft assembly, an I-shaft, a universal joint, steer-by-wire components, or any other features located opposite the input device 22. In other words, the steering column 26 may have a mechanical connection to the steering linkage (also referred to as a rack) or be a steer-by-wire system that does not require a continuous mechanical connection. The output assembly 28 may be connected to a power assist assembly 34 via a connection 36. The connection 36 may be a steering gear input shaft, a continuation of the pinion shaft assembly, or wired or wireless digital communication protocols.

[0015] The power assist assembly 34 may be operatively connected to a steering linkage 40 via a steering gear assembly. In operation, actuation of the driver input 22 causes a corresponding movement of the power assist assembly 34 and causes the steering linkage 40 to steer an associated vehicle.

[0016] With reference to Fig. 2, a housing 50 of a rack assembly 26 is shown. The housing 50 has a mounting bushing 52 that is inserted into a recess or opening 54 of the housing 50. The mounting bushing 52, in a fully assembled state, cooperates with a frame (not shown). In particular, a bushing surface 56 is in contact with a frame surface.

[0017] To prevent relative movement between the steering gear and the frame 50, an otherwise smooth surface 56 of a mounting bushing 52 is textured. In particular, the textured surface 56 of the mounting bushing is a surface that interacts with the steering gear when mounted. The term "textured" refers to a roughening of the mounting bushing surface 56 to increase the coefficient of friction on the surface 56. Therefore, the surface 56 may also be referred to herein as a friction surface. Texturing the mounting bushing surface significantly increases the coefficient of friction. This increase provides sufficient friction to prevent movement between the steering gear and the frame 50.

[0018] Although it is described and illustrated above that the surface 56 of the mounting bushing 52 is textured, it is contemplated that the frame surface is textured instead of the surface 56 of the mounting bushing 52.

[0019] According to the invention, the selection of the surface of the component that is textured to increase friction depends on a hardness property of the material. According to the invention, the component with the harder material property is the surface to be textured. For example, in one embodiment, the frame is formed from a first material having a first hardness, and the mounting bushing 52 is formed from a second material having a second hardness that is greater than the first hardness, such that the surface 56 of the mounting bushing is the surface that is textured. As another example, the frame is formed from a first material having a first hardness, and the mounting bushing 52 is formed from a second material having a second hardness that is less than the first hardness, such that the frame surface is the surface that is textured.

[0020] Although the embodiments described herein provide an example of a steering system, it should be appreciated that other types of assemblies may also slip relative to a mounting surface, and the texturing disclosed herein results in less slippage. Accordingly, the textured surface assembly disclosed herein may generally benefit a friction assembly for assembled components. Here, a first component has a first interface, a second component has a second interface, and the first interface and the second interface are in contact in an assembled state. One of the first and second interfaces is textured to form a friction surface. Advantageously, the surface to be textured is located on the component with the harder material property.

[0021] The surface texturing can be performed using various processes. According to the invention, the texturing is achieved by laser texturing. For example, the surface can be textured by laser etching. An example of the textured surface of the mounting bushing 52 is shown in Fig. 3 shown more clearly.

[0022] The assemblies disclosed herein also provide a method of manufacturing an assembly of interface-forming components. The method includes comparing a first hardness of a first material of a first component with a second hardness of a second material of a second component, and then determining which of the first and second materials is a harder material. Texturing the harder material with a laser to form a friction surface is performed, and the first and second components are assembled such that the friction surface forms an interface between the first and second components. As discussed herein, the texturing is performed by a laser process, such as etching.

[0023] Although the invention has been described in detail in connection with only a limited number of embodiments, it is to be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention may be modified to incorporate any number of alterations, modifications, substitutions, or equivalent arrangements not heretofore described, but which fall within the spirit and scope of the invention. In addition, although various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Furthermore, any feature, element, component, or advantage of any embodiment may be utilized in connection with any other embodiment. Accordingly, the invention is not to be considered limited by the foregoing description.

Claims

[1] Steering system (20), comprising: a steering gear; a frame (50) having a frame surface; and a bushing (52) having a bushing surface (56) in operative contact with the frame surface and the steering gear, the bushing surface (56) or the frame surface being textured to form a friction surface; wherein the textured surface, be it the frame surface or the bushing surface (56), is textured with a laser; wherein the frame (50) is formed from a first material having a first hardness; wherein the bushing (52) is formed from a second material having a second hardness different from the first hardness; and wherein the component having the greater hardness comprises the textured surface. [2] The steering system (20) of claim 1, wherein one of the frame surface and the bushing surface (56) is laser etched to form the friction surface.

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