Patent Application
20200040937
The present invention is related generally to socket assemblies and, more particularly, to socket assemblies of the type for use in vehicle suspension and steering assemblies.
Socket assemblies of the type that are generally used in automobile suspension and steering systems often include a housing; a ball stud; one or more bearings; and a preloading washer, such as a Belleville washer. To meet certain automotive socket design requirements, the ball stud and bearings are often made of hardened materials. However, as these components wear against one another during the operating life, friction can be generated between the bearing and ball stud, and that friction can produce heat, which ultimately can cause the preload properties of the washer to diminish via altering of material properties of the washer, including causing the washer to take-on a heat-set, undesirably. In addition, the friction between the bearing and the ball stud and between the bearing and washer can prevent the bearing from aligning itself in assembly and during use, thereby diminishing the useful life of the socket assembly.
This section provides a general summary of some of the objects, advantages, aspects and features provided by the inventive concepts associated with the present disclosure. However, this section is not intended to be considered an exhaustive and comprehensive listing of all such objects, advantages, aspects and features of the present disclosure.
It is an object of the present disclosure to provide a socket assembly having a preload washer that overcomes disadvantages of known socket assemblies.
It is a further object of the present disclosure to provide a method of constructing a socket assembly having a preload washer that overcomes disadvantages of known methods of constructing socket assemblies.
It is a further object of the present disclosure to provide a socket assembly that is economical in manufacture and assembly and that exhibits a long and useful life.
In accordance with these objectives, as well as others, which will be appreciated by those possessing ordinary skill in the art of socket assemblies, the present disclosure is directed to providing a socket assembly for motor vehicle and non-vehicle applications and to a method of construction thereof.
In accordance with one aspect, the present disclosure is directed to a socket assembly which advances the art and improves upon currently known socket assemblies for motor vehicles.
In another aspect, the present disclosure is directed to a method of construction of a socket assembly which advances the art and improves upon currently known methods of construction for socket assemblies for motor vehicles.
In accordance with these and other objects, advantages, and aspects, a socket assembly is provided including a housing having an inner bore which contains a ball portion of a ball stud; one or more bearings for low friction engagement with a ball portion of the ball stud; and a preload imparting washer. The preload washer is compressed to impart a biasing force on the one or more bearings to impart a desired preload within the socket assembly. The preload washer has an outer coating of a low friction, heat insulating material thereon to enhance the low friction operational performance and increase the longevity of useful life of the socket assembly.
In accordance with another aspect of the disclosure, the preload washer can be provided as a Belleville washer having the outer coating thereon.
The low friction aspect provided by the coating on the preload washer reduces the generation of heat within the socket assembly, thereby preventing grease from adversely decreasing in viscosity and escaping the housing, while also allowing the bearing engaging the preload washer to self-align within the inner bore, thereby allowing the bearing to attain an optimal functional position within the inner bore in optimally aligned relation with the ball portion of the ball stud. The heat reducing and heat insulating aspects of the coating also protect the preload washer from losing its “as manufactured” material properties, which if not prevented could cause the preload washer to lose its preloading capacity. As a result, the coating enhances functionality, increases durability and increases operating life of the socket assembly.
In accordance with another aspect of the disclosure, a socket assembly includes a housing having an inner bore extending along a central axis between a closed first end and an open second end. At least one bearing is disposed in the inner bore, wherein the at least one bearing has a bearing surface and a support surface opposite the bearing surface. The socket assembly also includes ball stud having a shank portion extending outwardly from the housing through the open second end and a ball portion disposed in the inner bore. Further yet, at least one preload washer biases the at least one bearing into engagement with the ball portion of the ball stud. The at least one preload washer has an outer coating of a low friction, heat insulating material.
In accordance with another aspect of the disclosure, the outer coating can engage the support surface of the at least one bearing to facilitate heat reduction and to facilitate self-aligning of the at least one bearing relative to the ball stud.
In accordance with another aspect of the disclosure, the at least one bearing can include a lower bearing captured between the ball portion of the ball stud and the closed first end of the housing, wherein the outer coating engages the support surface of the lower bearing.
In accordance with another aspect of the disclosure, the inner bore can be provided having a first diameter adjacent the closed first end and the lower bearing can be provided having an outer diameter that is less than the first diameter, wherein the outer coating facilitates radial movement the lower bearing to facilitate self-alignment of the lower bearing with the ball portion of the ball stud.
In accordance with another aspect of the disclosure, the outer coating can be provided to engage the closed first end of the housing, thereby further reducing the generation of heat due to friction.
In accordance with another aspect of the disclosure, the outer coating can be provided to encapsulate the preload washer, thereby maximizing protection to the preload washer against the effects of heat within the housing.
In accordance with another aspect of the disclosure, the preload washer can be provided as a Belleville washer.
In accordance with another aspect of the disclosure, the socket assembly can further include a dust boot having a flexible boot body extending between an upper end configured in sealed engagement about the shank portion of the ball stud and a lower end configured in sealed engagement with the open second end of said housing, wherein the at least one preload washer can be provided to engage the lower end of the dust boot.
In accordance with another aspect of the disclosure, the at least one bearing can include an upper bearing captured between the lower end of the dust boot and the ball portion of the ball stud.
In accordance with another aspect of the disclosure, the at least one preload washer can be bonded to the lower end of the dust boot, thereby simplifying handling during assembly.
In accordance with another aspect of the disclosure, the at least one preload washer can be overmolded with material of the dust boot, thereby simplifying manufacture and reduce the cost associated with manufacture and assembly.
In accordance with another aspect of the disclosure, the at least one preload washer can be encapsulated within the lower end of the dust boot.
In accordance with another aspect of the disclosure, the socket assembly can further include a dust boot having a flexible boot body extending between an upper end configured in sealed engagement about the shank portion of the ball stud and a lower end configured in sealed engagement with the open second end of the housing, wherein the at least one bearing can include an upper bearing captured between the lower end of the dust boot and the ball portion of the ball stud, wherein the at least one preload washer engages the lower end of the dust boot.
These and other features and advantages of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to
The socket assembly 20 includes a housing 22 with an inner bore that extends along an axis A from a closed or substantially closed first end 24 to an open second end 26. At the first end 24, the housing 22 presents a lower wall 28 with an inner surface 27 and an exterior surface 29. The housing 22 is preferably made of a metal, such as steel or an alloy steel, and may be shaped through any suitable process or combination of processes including, for example, forging, casting, machining from a billet, etc. In the exemplary embodiment, the housing 22 is a cartridge for press-fitting into an opening of the control arm. However, the housing could alternately be integrally formed with another component, e.g., a control arm or a tie rod end, or otherwise configured for attachment to a support member, such as via external or internal threads. In the exemplary embodiment, the lower wall 28 of the housing presents a lubricant opening 30 which receives a grease fitting 32 to convey a lubricant into a first portion 34 of the inner bore to initially lubricate the socket assembly 20 and to re-lubricate the socket assembly 20 as part of routine maintenance. It is to be appreciated that the lubricant opening 30 does not have to be on the lower wall 28, but could instead be located on any suitable portion of the housing 22.
The inner bore of the housing 22, by way of example and without limitation, has a progressively increasing diameter from the first end 24 to the second end 26. Specifically, the inner bore has the first portion 34 with a first diameter D1 adjacent the closed first end 24 and shown as extending from the close first end 24, a second portion 36, a third portion 38 with a second diameter D2 that is larger than the first diameter D1 and a fourth portion 39 adjacent the open second end 26 with a third diameter D3 that is greater than the second diameter D2. Between the second and third portions 36, 38, the housing 22 presents a first shoulder 40 which faces toward the open second end 26. Between the third and fourth portions 38, 39, the housing 22 presents a second shoulder 41 which also faces toward the open second end 26. It is to be recognized the inner bore could be otherwise configured, such as being cylindrical, by way of example and without limitation.
A lower bearing, also referred to as backing bearing 42, is received in the first portion 34 of the inner bore and is captured between the ball portion 52 of the ball stud 50 and the closed first end 24. The backing bearing 42 has a semi-spherically curved first bearing surface 44 which faces axially toward the second open end 26 and an opposite support surface 45 which faces axially toward the closed first end 24. The backing bearing 42 has an outer diameter which is less than the first diameter D1 of the first portion 34 of the inner bore. As such, the backing bearing 42 is desirably movable within the first portion 34 of the inner bore in a radial direction relative to the housing 22 to allow the backing bearing 42 to float radially within the first portion 34 of the inner bore to in effect, self-align itself radially relative to the ball stud 50 and the ball portion 52 thereof, thereby being able to attain low friction, uniformly nested sliding contact with the ball portion 52. The first bearing surface 44 of the exemplary embodiment is provided with a plurality of first grooves 48 (
The socket assembly 20 further includes a ball stud 50 which is partially received in the inner bore of the housing 22. Specifically, the ball stud 50 includes a ball portion 52 that is fully disposed in the inner bore and a shank portion 54 which projects out of the inner bore through the open second end 26. The exemplary embodiment of the shank portion 54 extends from the ball portion 52 to a distal end which is threaded for receiving a nut to connect the shank portion 52 with another component, e.g., a knuckle. Alternately, the shank portion 54 could be configured for connection with the other component through any suitable means. The ball portion 52 of the ball stud 50 has a generally semi-spherically curved outer surface which has a similar radius of curvature to the first bearing surface 44 of the backing bearing 42. The outer surface of the ball portion 52 is in sliding contact with the first bearing surface 44 of the backing bearing 42 for allowing the ball stud 50 to rotate or pivot relative to the backing bearing 42 and the housing 22 during operation of the suspension assembly. With the backing bearing 42 being able to self-align, the first bearing surface 44 is able to automatically self-locate in optimally aligned relation for low friction, uniform contact with ball portion 52. The backing bearing 42 is preferably made of metal, such as steel or a steel alloy and may be shaped through any suitable process.
An upper bearing, also referred to as exit bearing 65, is received in the second portion 36 of the inner bore and has a second bearing surface 66 which is in sliding contact with the ball portion 52 of the ball stud 50. The second bearing surface 66, by way of example and without limitation, includes a semi-spherically curved portion 67 and a cylindrical portion 68. The semi-spherically curved portion 67 has a similar or same radius of curvature as the ball portion 52 and the first bearing surface 44 and is in sliding contact an opposite hemisphere of the ball portion 52 from the first bearing surface 44. The cylindrical portion 68 of the second bearing surface 66 extends past (i.e., below) and is in sliding contact with an equator, or center-line 86, of the ball portion 52 and has a generally constant diameter as viewed in cross-section for a predetermined length. Similar to the first bearing surface 44, the second bearing surface 66 may include one or more grooves for distributing a lubricant around the surface-to-surface contact between the second bearing surface 66 and the ball portion 52 of the ball stud 50 and for conveying the lubricant in the inner bore axially across the exit bearing 65. As shown in
The exit bearing 65 has a generally flat, planar upper surface 69 which faces toward the open second end 26 of the housing 22. Opposite of the upper surface 69, the exit bearing 65 has a lower surface 71 which is seated against the shoulder 40 of the housing 22 to establish a fixed distance between the lower wall 28 of the housing 22 and the exit bearing 65.
The socket assembly 20 further includes a dust boot 70 which is sealed against the housing 22 and against the ball stud 50 for trapping a lubricant, such as grease, in an interior of the socket assembly 20 and for keeping contaminants outside of the interior of the socket assembly 20. The dust boot 70 includes a boot body 76 which is made of a flexible sealing material, such as rubber or certain plastics. In the embodiment of
A preload washer 56, (also known as a washer spring), such as a Belleville spring washer, by way of example and without limitation, is positioned in the first portion 34 of the inner bore of the housing 22 and imparts a preload or biasing force on the backing bearing 42, such that backing bearing 42 is preloaded and biased toward the open second end 26 against the ball portion 52 of the ball stud 50 to maintain desired uniform, surface-to-surface contact between the first and second bearing surfaces 44, 66 and the outer surface of the ball portion 52, even as these surfaces wear during operation of the socket assembly 20. It should be appreciated that another type of compression spring, other than a Belleville washer, could alternately be employed.
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In each of the exemplary embodiments, the Belleville spring washer 56, 74 is covered on its upper and lower wear surfaces 58, 60, and is preferably fully encapsulated by an outer coating 82 that is made of a material which has low coefficient of friction and has high heat insulating properties. The coating 82 is preferably a film lubricant or a plastic material and may be applied to the Belleville spring washer 56, 74 through any suitable process, e.g., spraying, painting, plating, etc. The low coefficient of friction of the material that the coating 82 can be configured to engage one or more of the support surface 45, 69 of the respective bearings 42, 65 to reduce the amount of friction between abutting surfaces of the respective preload washer(s) 56, 74 and bearing(s) 42, 65, and thus, the amount of heat that may be generated due to relative movement between the Belleville spring washer 56, 74 and any bearing 42, 65 or other surface that contacts the Belleville spring washer 56, 74, such as the inner surface 27 of closed first end 24, is reduced. This reduction in heat generation prevents the viscosity of the grease contained in the socket assembly 20, 120 from decreasing, thereby inhibiting the grease from escaping the socket assembly 20, 120. The heat insulating properties of the coating 82 also protect against the material properties of the metal of the Belleville spring washer 56, 74 from changing, such as from preventing the preload washer 56, 74 from taking on a heat set or being tempered, for example, which could otherwise reduce the preload force applied by the Belleville spring washer 56, 74 on an adjacent bearing 42, 65, and ultimately reduce the operating performance of the socket assembly 20, 120. Further yet, as discussed above, the backing bearing 42 is desirably movable radially within the first portion 34 of the inner bore relative to the housing 22 to allow the backing bearing 42 to float radially and self-align itself radially relative to the ball stud 50 and the ball portion 52 thereof. The coating 82 facilitates radial movement of the lower bearing 42 to facilitate self-alignment of the lower bearing 42 with the ball portion 52, thereby allowing the lower bearing 42 to readily attain low friction, uniformly engaged sliding contact with the ball portion 52.
Another aspect of the present disclosure is for a method of making a socket assembly 20. The method includes the step of preparing a housing 22 with an inner bore which extends from a lower wall 28 at a generally closed first end 24 to an open second end 26. The lower wall 28 has an exterior surface with a conically shaped projection 90 that projects in an axial direction away from the second open end 26. The method continues with the step of inserting a preload washer, such as a Belleville spring washer 56, into the inner bore of the housing 22. The method proceeds with the step of inserting a backing bearing 42 with a first bearing surface 44 into the inner bore of the housing 22 such that the backing bearing 42 is movable in a radial direction relative to the housing 22 within the inner bore. The method continues with the step of inserting a ball portion 52 of a ball stud 50 into the inner bore of the housing 22 such that a shank portion 54 of the ball stud 50 extends from the ball portion 52 out of the inner bore through the open second end 26 of the housing 22. The method proceeds with the step of fixing an exit bearing 65 with a second bearing surface 66 into a fixed position within the inner bore of the housing 22. In the exemplary method, the exit bearing 65 is fixed between a shoulder 40 of the housing 22 and a radially extending lip 80 that is formed by swaging the open second end 26 of the housing 22. The method continues with the step of deforming the lower wall 28 at the generally closed first end 24 of the housing 22 to preload the Belleville washer 56 against the backing bearing 42 and urge the first bearing surface 44 of the backing bearing 42 against an outer surface of the ball portion 52 of the ball stud 50. In the exemplary method, the step of deforming is further defined as pressing the projection 90 until the exterior surface of the wall is generally flat. The lower wall 28 could be pressed, for example, with a ram.
It should be appreciated that the use of the orientation defining terms such as “upper” and “lower” herein is in reference to the orientation of the socket assembly 20 in the Figures and is not considered to require a particular orientation or otherwise be limiting.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. Additionally, it is to be understood that all features of all claims and all embodiments can be combined with each other as long as they do not contradict each other.
This application claims the benefit of U.S. Provisional Application Ser. No. 62/713,588, filed Aug. 2, 2018, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62713588 | Aug 2018 | US |
