This disclosure relates to a ball joint for a vehicle suspension or steering member, for example.
Ball joints are commonly used in vehicles for suspension or steering elements such as control arms or tie rod ends. The ball joint provides a connection that permits rotation of one element with respect to another while permitting articulation during a range of motion experienced during vehicle operation.
One example ball joint configuration provides a pre-molded plastic bearing cup to which the ball is inserted in a snap-fit relationship. The sub assembly is then inserted into a bore of a housing, and a cover is arranged over the bearing.
Providing a consistent torque between the ball and its support structure is important so as to not provide any undesired free play or too stiff of a joint. To this end, one approach over-crimps a lip of the housing onto the cover, which forces the bearing into further engagement with the housing and ball. This type of method is disclosed in U.S. Pat. No. 6,592,284 to Rechtien. Any surface imperfections in the housing are accommodated by the bearing flowing into any gaps. This assembly method is challenging in that it is difficult to provide a consistent operational torque. Another internal tolerance compensation feature is disclosed in U.S. Pat. No. 2,993,717 to Gottschald, which uses a spring to apply a load to the ball.
U.S. Pat. No. 6,941,656 to Michioka discloses a ball joint that has the outer housing cast over a resin bearing. This method eliminates any gaps between the housing and the bearing but limits the housing material to relatively low strength zinc or aluminum die cast material so as not to melt the resin bearing during the casting process. Typically high load suspension applications require the housing to be made from a high strength steel.
In one exemplary embodiment, a method of manufacturing a ball joint includes arranging a ball in a bore of a housing, enclosing an end of the bore, injecting plastic into a space between the housing and the ball to form a bearing that has a bearing surface that engages the ball, shrinking the bearing to form a recess in the bearing surface, and filling the recess with a grease.
In a further embodiment of any of the above, the arranging step includes a ball that has a stud that extends from the ball. The ball and stud includes a hole therethrough. The filling step includes injecting grease through the hole and into the recess.
In a further embodiment of any of the above, the method includes the step of sealing the hole subsequent to performing the filling step.
In a further embodiment of any of the above, the enclosing step includes securing a cover over the ball. The injecting step includes the bearing surface that engages around the cover to form a cap that is integrally connected to the bearing to provide a monolithic plastic structure.
In a further embodiment of any of the above, the cover securing step includes one of welding or swaging.
In a further embodiment of any of the above, the enclosing step includes swaging the housing toward the ball.
In a further embodiment of any of the above, the plastic injecting step includes overmolding a cap over the cover and connected to the bearing to provide a monolithic plastic structure.
In a further embodiment of any of the above, the cover includes an opening. The plastic injecting step includes molding the cap and the bearing as a monolithic structure with a connector that is arranged in the opening and joins the bearing and the cap.
In a further embodiment of any of the above, the arranging step includes a ball that has a stud that extends from the ball. The ball and stud includes a hole therethrough, and includes the step of plugging the hole prior to performing the plastic injecting step.
In a further embodiment of any of the above, the cover includes an elongate cavity. The injecting step includes filling the elongate cavity with plastic. The shrinking step includes shrinking the bearing at a location opposite the elongate cavity to create the recess.
In a further embodiment of any of the above, the injecting step includes forming a bearing with a perimeter lip that is arranged about a circumference of the ball at the housing. The grease filling step includes deforming the bearing to pull the perimeter lip into the housing and provide an enhanced seal between the ball and housing.
In a further embodiment of any of the above, the grease is a first grease, and includes a step of installing a boot onto the housing with a second grease that is different than the first grease that is arranged between the boot and the ball. The perimeter lip separates the first and second greases.
In a further embodiment of any of the above, the housing includes a hole on a side opposite the stud, and the hole is in fluid communication with the recess that is formed on a side of the bearing facing the ball stud and aligned with the elongate cavity. The hole is filled with grease.
In a further embodiment of any of the above, the arranging step includes the ball that has a stud that extends from the ball. The ball and stud include a hole therethrough, and includes the step of plugging the hole prior to performing the plastic injecting step.
In a further embodiment of any of the above, the arranging step includes the ball that has a stud that extends from the ball. The ball and stud include a hole therethrough. The filling step includes injecting grease through the hole and into the recess.
In a further embodiment of any of the above, the method includes the step of sealing the hole subsequent to performing the filling step.
In a further embodiment of any of the above, the bearing has first and second sides opposite one another to provide a thickness. The first side provides the bearing surface that forms a spherical surface. The second side has a protrusion opposite the spherical surface that is received in and fills an elongate cavity in the housing. A recess is provided in the spherical surface directly opposite the protrusion relative to the thickness.
The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
Referring to
In a two-piece housing configuration, a cover 24 forms another portion of the housing structure and is secured to one end of the bore 52, such as by welding, to enclose and capture the ball 18 within the housing 16. A bearing 22, constructed from a material such as acetyl, is injection-molded into the space between the ball 18 and the housing 16. A boot 26 with a seal rim 30 is provided over the stud 20 and is secured to the housing 16 opposite the cover 24 to seal the ball 18 from the elements and prevent corrosion.
Referring to
One side of the domed portion 32 provides a spherical surface 38 having circumferentially spaced apart grooves 42 adjoining and radiating outwardly from an opening 44 in the cover 24. The grooves 42 may be formed by coining, for example.
A plastic injection molding process is shown in
Multiple mold portions engage various components of the ball joint 14 to maintain a space provided by first and second cavities 70, 72 on opposite sides of the cover 24 and that are in fluid communication with one another. In one example, a first mold portion 58 abuts the housing 16 to create a second cavity 72 between the first mold portion 58 and a bottom portion of the housing 16 and the cover 24. A second mold portion 60, such as a pin, is inserted into the hole 28 to plug and block any molten plastic from entering the hole 28. A third mold portion 62 includes first and second chamfers 64, 66 that respectively abut the housing 16 and the ball 18 to prevent molten plastic from escaping the first cavity 70 during molding.
A plastic injector 63 injects molten plastic through an outlet in the first mold portion 58 into the second cavity 72, through the opening 44 in the cover 24 and into the first cavity 70.
The opening 44 is aligned with the hole 28. During injection, plastic flows through the opening 44 forming protrusions 77 that fill the grooves 42 in the cover 24 on a side facing the ball 18. A spherical surface is formed on a first side 82 of the bearing 22 that engages the corresponding spherical surface of the ball 18. A depression 69 is provided in the bearing surface at the first side 82 of the bearing 22 and is formed by an end of the second mold portion 60, such that the depression 69 is beneath the hole 28 and aligned with the opening 44.
An end of the housing 16 includes an annular projection 73 circumscribing the bore 52. A cap 74 is over-molded over the cover 24, the weld 50 and a portion of the annular projection 73 (with extension 71) to provide a water-tight seal and prevent corrosive elements from entering the ball joint 14. A monolithic plastic structure is thus formed including the bearing 22 joined to the cap 74 by a connector 75.
As the plastic cools, it shrinks slightly, approximately 2%. The wall thickness of the bearing 22 varies due to the presence of the grooves 42 in the cover. Thus, a first thickness 76 of the bearing 22 in the area of the grooves 42 is larger than that of a second thickness 78 provided by the adjacent bearing structure, as shown in
As shown in
As shown in
Variations of the ball joint 14 described above may also be used. Like numerals (e.g., 14, 114, 214 for “ball joints”) are used to describe similar elements between the various embodiments. A one-piece housing ball joint 114 is shown in
Referring to
As described in connection with the ball joint 14 shown in
As shown in
The bearing 122, 222 of each of the ball joints 114, 214 is injected through the base of the housing 116, 216 opposite the stud 120, 220. The plastic injection molding process for the ball joint 214 is shown in
A first cavity 270 is provided between the ball 218 and the cover 224, and a second cavity 272 is provided between the cover 224 and the first mold portion. The first and second passageways 261b and 261c are aligned respectively with the first and second cavities 270, 272, which correspondingly provide the bearing 222 and the cap 274. The lip 88 described in
The ball joints 114, 214 are shown in
It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom. Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention.
Although the different examples have specific components shown in the illustrations, embodiments of this invention are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples.
Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.
This application is a Divisional of U.S. patent application Ser. No. 16/638,843 filed Feb. 13, 2020, which is a United States National Phase Application of PCT Application No. PCT/CA2018/050999 filed Aug. 16, 2018, which claims priority to Untied States Provisional Application No. 62/546,091, which was filed on Aug. 16, 2017, and U.S. Provisional Application No. 62/681,990, which was filed on Jun. 7, 2018.
Number | Date | Country | |
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62546091 | Aug 2017 | US | |
62681990 | Jun 2018 | US |
Number | Date | Country | |
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Parent | 16638843 | Feb 2020 | US |
Child | 17981918 | US |