Electrically conductive overmolded hinge bushing

Abstract

Electrically conductive overmolded bushings for use in automotive articulation links and processes for forming the overmolded bushings are described. The overmolded bushing comprises an electrically conductive, carbon fiber filled polymer composite material and at least one steel hinge section of at least two metal hinge sections to be connected, the steel hinge section being provided with a pivot pin hole. The polymeric composite material is overmolded to the pivot pin bore to form a bushing. The bushing is formed with a circumferential flange extending radially from the pivot pin bore. The circumferential flanges are each provided with at least one circumferential rib. The bushing is also formed with an inner cylindrical wall integral with the circumferential flange and abutting against the pivot pin bore. The carbon fibers in the liner are exposed by compressing the at least one circumferential rib during assembly of the hinge to establish an electrical connection between the at least two metal hinge sections.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Provisional Patent Application 63 / 537,916, filed September 12, 2023, the contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of articulation components, and more particularly to bushings for automotive articulation components. Background Technology

[0003] In the hinges of some car hoods or trunk lids, two metal sections are connected by a riveted pivot pin, which must be rotatably connected at the joint. Typically, a very low-friction material is chosen for the bushing to facilitate rotation at the joint. Common choices for this bushing material are PTFE (polytetrafluoroethylene) or similar PFAS (perfluoroalkyl and polyfluoroalkyl substances). This type of bushing is durable and effective during repeated rotations at the joint. In many such bushings, a steel sleeve is positioned outside the PTFE portion of the bushing (i.e., the steel sleeve abuts against the bore, and the pin rotates on the PTFE surface inside the bushing). The steel sleeve contacts one of the metal sections of the joint in a non-rotational manner, while the PTFE portion contacts the pivot pin in a rotatable manner to allow rotation of the joint. This conventional bushing uses two very different materials—steel and PTFE—to form the complete bushing.

[0004] In automobile manufacturing, painting of the hood or trunk lid, as well as other body parts, is often done after the hinges of the hood or trunk lid have been installed. Electrostatic painting is typically used. Currently, current must pass through the hinges to generate a potential in the hood or trunk lid. A characteristic of this type of PTFE bushing is its high resistivity, and consequently, low electrical conductivity. Therefore, conventional PTFE bushings would impede the flow of current through the hinges to the hood or trunk lid. Some PTFE bushings have a steel backing. One solution to this resistance / conductivity problem is to create recesses in the steel sleeve wall that extend through the PTFE portion of the steel-backed bushing to provide a path for the electrical connection through the bushing and hinges.

[0005] Recently, concerns have arisen regarding the use of so-called “permanent chemicals”—including PTFE and other PFAS materials—which persist in the environment for extended periods and can cause health and pollution problems. Therefore, there is a need for a hinged bushing that offers similar properties to PTFE bushings, provides electrical conductivity but has a more benign environmental impact, and preferably has a simpler structure. Summary of the Invention

[0006] We have discovered that a bushing with low friction and relatively low resistivity can be obtained by overmolding a carbon fiber-filled polymer composite material onto a metal segment of a hinge, the overmolding covering and surrounding the pivot pin hole in that metal segment. The overmolded bushing includes a central cylindrical wall integral with opposing circumferential flanges. One or more circumferential ribs formed on the flanges during overmolding help retain foreign matter outside the assembled hinge. One or more longitudinal ribs formed on the central inner cylindrical wall of the bushing can contribute to a strong engagement between the bushing and the hinge's pivot pin. Surprisingly, by compressing or crushing these ribs during hinge assembly to expose the carbon fibers to the metal segments of the hinge, the electrical connectivity between the metal segments of the hinge is significantly increased.

[0007] According to some embodiments, an electrically conductive overmolded bushing for use in an automotive hinge connection is provided, the bushing comprising an electrically conductive, carbon fiber-filled polymer composite material. The polymer composite material is overmolded into a pivot pin hole in a steel hinge segment to form the bushing. The bushing has circumferential flanges extending radially from the pivot pin hole. The bushing also has an internal cylindrical wall integral with the circumferential flanges and abutting against the pivot pin hole. Each circumferential flange is provided with at least one circumferential rib. Assembly of the hinge crushes these circumferential ribs to expose the carbon fibers to the metal segment of the hinge, thereby increasing the electrical connection between the segments.

[0008] In another embodiment, each circumferential flange is provided with multiple circumferential ribs.

[0009] In another embodiment, the inner cylindrical wall is provided with at least one longitudinal rib.

[0010] In another embodiment, the inner cylindrical wall is provided with multiple longitudinal ribs.

[0011] In another embodiment, the polymer composite material used for the bushing is lubricated polyamide 4 / 6 containing 30% carbon fiber.

[0012] According to another embodiment, a process is provided for forming an electrically conductive overmolded bushing for use in an automotive articulation connection, comprising: overmolding an electrically conductive, carbon fiber-filled polymer composite material into a pivot pin hole of a first steel articulation segment to form a bushing; during overmolding, integrally forming at least one circumferential rib on each of two opposing circumferential flanges extending radially from the pivot pin, and integrally forming an inner cylindrical wall of the bushing; riveting the pivot pin through the bushing to rotatably connect the first steel articulation segment and the second steel articulation segment; the riveting causing at least one circumferential rib to be compressed to expose the carbon fiber and establish an electrical connection between the first and second steel articulation segments through the bushing.

[0013] In another embodiment of this process, a plurality of circumferential ribs are formed in each circumferential flange.

[0014] In another embodiment of the process, at least one longitudinal rib is formed on the inner cylindrical wall.

[0015] In another embodiment of the process, multiple longitudinal ribs are formed on the inner cylindrical wall.

[0016] In another embodiment of the process, the polymer composite of the bushing comprises lubricated polyamide 4 / 6 containing 30% carbon fiber.

[0017] In another embodiment, the polymer composite material of the bushing is neither PFAS nor PTFE. Attached Figure Description

[0018] To better understand the various implementation methods described herein and to clearly illustrate how they are implemented, reference will now be made to the accompanying drawings by way of example only, wherein: Figure 1 A four-bar automotive articulation assembly including an overmolded bushing is depicted according to a non-limiting embodiment. Figure 2 A non-limiting embodiment is depicted, showing a section along section AA including a molded overlay bushing. Figure 1 Cross-sectional view of the connecting part; Figure 3A A bushing according to a non-limiting embodiment is depicted; Figure 3B A description of a non-limiting embodiment is provided. Figure 1 The cross-sectional view of the bushing shown; Figure 4 A description of a non-limiting embodiment is provided. Figure 1 A cross-sectional view of a four-bar automotive articulated assembly, in which the connection between the pivot pin and the overmolded bushing has been removed; Figure 5 A description of a non-limiting embodiment is provided. Figure 2 A cross-sectional view of the connecting part, in which the pivot pin has been removed and has Figure 2 The bushing shown; Figure 6 A cross-sectional view of an isolated overmolded bushing according to a non-limiting embodiment is depicted; Figure 7A and Figure 7B A connection including an overmolded bushing, according to a non-limiting embodiment, is depicted before installation. Figure 7A ) and after installation ( Figure 7B A cross-sectional view of ) and Figure 8 A method for forming an electrically conductive overmolded bushing for use in an automotive hinge connection, according to a non-limiting embodiment, is described.

[0019] The embodiments, examples, and alternatives described in the preceding paragraph, claims, or the following description and drawings, including any of their various aspects or corresponding individual features, may be employed independently or in any combination. Features described in connection with one embodiment apply to all embodiments unless those features are incompatible. Detailed Implementation

[0020] A fiber-filled polymer composite material is described, which is overmolded into a metal segment of a hinge to cover and surround a pivot pin hole in that segment; the metal is typically steel. This typically produces a bushing with low friction and relatively low resistivity. The polymer composite material of the bushing does not have the environmental problems associated with PTFE or PFAS bushing materials. The overmolded bushing is ready to install the pivot pin to complete the hinge. Unlike freestanding PTFE bushings, it typically does not need to be installed into the pivot pin hole before installing the pivot pin. Furthermore, the bushing is overmolded from a single polymer composite material, eliminating the need for a steel backing.

[0021] Overmolding technology also allows for the formation of crushing ribs on the flange surrounding the pivot pin hole, which helps prevent foreign objects such as dust or other debris from entering the interior of the finished hinge connection. One or more circumferential crushing ribs can be provided on each bushing flange to provide a single barrier or a sequence of barriers to block dust and other foreign objects. Surprisingly, compressing or crushing these circumferential ribs during hinge assembly exposes carbon fibers to the steel sections of the hinge and significantly increases the electrical connection between these hinge sections separated by the bushing. Longitudinal crushing ribs can also be added to the inner cylindrical wall of the bushing to provide a more robust connection to the pivot pin, thereby increasing the stability of the hinge. During overmolding, the flange and the inner wall of the bushing are formed integrally.

[0022] The suitable polymer for the bushing is a lubricated polyamide 4 / 6 containing 30% carbon fiber, such as Stanyl TW200B.

[0023] Therefore, polymer composite overmolded bushings meet the functional requirements previously met by PTFE bushings without the same environmental problems. Overmolded bushings offer a single material, low-friction surface without the need for additional lubrication. Their electrical conductivity makes them suitable for electrostatic painting of engine hoods, trunk lids, or any similar hinge components. Furthermore, circumferential crushing ribs on the bushing flange prevent foreign matter from entering the connection, while significantly increasing the electrical connection between the bushing-separated metal hinge segments during hinge assembly. Longitudinal crushing ribs on the inner cylindrical wall of the bushing provide a radial interference fit between the bushing and the pivot pin, eliminating radial backlash in the connection.

[0024] It should be understood that, for the sake of simplicity and clarity, reference numerals may be repeated in the drawings where deemed appropriate to indicate corresponding or similar elements. Furthermore, numerous specific details are set forth to provide a thorough understanding of the exemplary aspects of this application as described herein. However, it will be understood by those skilled in the art that the exemplary aspects described herein can be practiced without these specific details. In other instances, well-known methods, processes, and components are not described in detail so as not to obscure the exemplary aspects described herein. Moreover, the description should not be construed as limiting the scope of the exemplary aspects described herein. Any system, method step, method block, component, part of a component, etc., described herein in the singular should also be construed as including the plural description of such systems, method steps or tasks, components, parts of a component, etc., and vice versa.

[0025] Pay attention to the direction. Figure 1 The document describes a four-bar articulated assembly 100 according to a non-limiting embodiment. The articulated assembly 100 is typically used in vehicle hood hinges; however, any suitable connecting element application for the described overmolded bushing and related processes is contemplated. The articulated assembly 100 includes a hood bracket 102, a body bracket 104, a long link 106, a short link 108, and a pivot pin 110. The articulated assembly 100 also includes an overmolded bushing 112 (also referred to herein as an electrically conductive overmolded bushing 112).

[0026] like Figures 2 to 7BAs shown, the overmolded bushing 112 comprises an electrically conductive, carbon fiber-filled polymer composite material 114. This overmolded bushing is preferably non-PFAS and non-PTFE. According to some embodiments, the polymer composite material comprises lubricated polyamide 4 / 6 containing 30% carbon fiber, such as Stanyl® TW200B. The carbon fiber contributes to providing at least some electrical conductivity. According to some embodiments, the resistivity is at most 100 Ω. The resulting overmolded bushing allows hinges and connections to be processed at high temperatures. For example, bushing 112 can be exposed to dry heat up to 200°C.

[0027] At least one of the at least two metal hinge segments to be connected is provided with a pivot pin hole, such as engine hood bracket 102 and short connecting rod 108 having hole 116. Figure 4 According to some embodiments, the metal is steel, but any suitable metal is contemplated. A polymer composite material 114 is overmolded into the bore 116 to form a bushing 112. The bushing 112 includes a circumferential flange 120 extending radially from the pivot pin bore 116. Although... Figures 2 to 6 The circumferential flanges are depicted with unequal radial lengths, but according to some embodiments, the circumferential flanges have equal or substantially equal radial lengths. The bushing 112 also forms an inner cylindrical wall 122 integral with the circumferential flanges and abutting against the pivot pin hole 116.

[0028] For injection-molded overmolded parts, most of the reinforcing fibers tend to remain below the outer surface layer, resulting in high resistivity at the outer surface layer. To address this issue, the bushing 112 incorporates at least one crush rib that exposes the electrically conductive fibers when compressed or otherwise deformed. Each circumferential flange 120 is provided with at least one circumferential rib 124. According to some embodiments, the circumferential rib 124 comprises one circumferential rib. According to some embodiments, each circumferential flange 120 is provided with a plurality of circumferential ribs 124.

[0029] According to some embodiments, the inner cylindrical wall 122 is provided with at least one longitudinal rib, such as a longitudinal rib 126. According to some embodiments, the longitudinal rib 126 includes one longitudinal rib. According to some embodiments, the longitudinal rib 126 includes multiple longitudinal ribs.

[0030] During the assembly of the hinge, carbon fibers in the bushing 112 are exposed by compressing at least one circumferential rib 124 to establish an electrical connection between the two steel hinge segments. For example, during the assembly of the connection by means of riveting or stamping, the circumferential ribs and / or longitudinal ribs deform, and the inner diameter of the bushing increases as the pin is pressed into the pivot pin hole 116. Figure 7A and Figure 7BSimilarly, these deformations expose at least some of the electrically conductive carbon fibers in the overmolded surface. The carbon fibers then come into contact with adjacent metal parts (metal hinge segments) to form electrical conduits through the joint. The resulting radial interference fit typically eliminates radial clearance in the joint, and the deformed crushing ribs prevent foreign matter such as dust from entering the joint.

[0031] Pay attention to the direction. Figure 8 This describes an example method 200 for forming an electrically conductive overmolded bushing used in automotive articulation connections. To aid in explaining method 200, it is assumed that method 200 uses, for example... Figures 1 to 7B The connection and bushing shown are used for execution. Furthermore, the following discussion of method 200 will enable... Figure 1 Further understanding is provided regarding the connections and bushings depicted in Figure B and the various components described herein. However, it should be understood that method 200 can vary and does not need to operate exactly as discussed herein, and such variations are all within the scope of this application. It is also emphasized that, unless otherwise stated, method 200 does not need to be performed in the exact order shown; and similarly, the various blocks can be performed in parallel rather than sequentially. Therefore, the elements of method 200 are referred to herein as “blocks” rather than “steps.”

[0032] In frame 202, an electrically conductive, carbon fiber-filled polymer composite material is overmolded into the pivot pin hole of the first steel hinge section to form a bushing, such as bushing 112. This polymer composite material is preferably non-PFAS and non-PTFE. For example, according to some embodiments, the polymer composite material comprises lubricated polyamide 4 / 6 containing 30% carbon fiber.

[0033] In frame 204, during the overmolding of frame 202, at least one circumferential rib, such as circumferential rib 124, is integrally formed on each of two opposing circumferential flanges extending radially from the pivot pin, and an inner cylindrical wall of the bushing is integrally formed. According to some embodiments, one circumferential rib is formed on each circumferential flange. According to some embodiments, multiple circumferential ribs are formed in each circumferential flange. According to some embodiments, simultaneously or concurrently with frame 204, at least one longitudinal rib, such as longitudinal rib 126, is formed on the inner cylindrical wall. According to some embodiments, one longitudinal rib is formed. According to some embodiments, multiple longitudinal ribs are formed.

[0034] In frame 206, a pivot pin is riveted through the bushing to rotatably connect the first metal hinge segment to the second metal hinge segment, such as by riveting pivot pin 110 through bushing 112. As described above, the riveting causes at least one circumferential rib to be compressed, which exposes at least some of the carbon fibers in the polymer composite material and establishes an electrical connection between the first and second metal hinge segments through the bushing.

[0035] It should also be understood that, for the purposes of this application, the language “at least one of X, Y and Z” or “one or more of X, Y and Z” can be interpreted as only X, only Y, only Z, or any combination of two or more items X, Y and Z (e.g., XYZ, XYY, YZ, ZZ, XX, XY).

[0036] In this application, a component may be described as being "constructed" or "capable" of performing one or more functions. Generally, it should be understood that a component constructed or capable of performing a function is configured or capable of performing that function, or adapted to perform that function, or operable to perform that function, or otherwise capable of performing that function.

[0037] Furthermore, components in this application may be described as "operably connected to" or "operably coupled to" other components. It should be understood that these components are connected or coupled to each other in a manner that performs a certain function. It should also be understood that "connection," "coupling," etc., as used in this application, include both direct and indirect connections between components.

[0038] References to "an embodiment," "implementation," "mode of implementation," "variation," etc., in this application indicate that the described embodiment, implementation, or variation may include a specific aspect, feature, structure, or characteristic, but not every embodiment, implementation, or variation must include that aspect, feature, structure, or characteristic. Furthermore, these phrases may, but do not necessarily, refer to the same embodiment mentioned in other parts of the specification. Moreover, when a specific aspect, feature, structure, or characteristic is described in connection with an embodiment, it is within the knowledge of those skilled in the art that the module, aspect, feature, structure, or characteristic can influence or connect with other embodiments, whether explicitly described or not. In other words, any module, element, or feature can be combined with any other element or feature in a different embodiment unless there is an obvious or inherent incompatibility or it is specifically excluded.

[0039] It should also be noted that claims can be drafted to exclude any optional elements. Therefore, this statement is intended as a preamble for using exclusive terms such as “only,” “merely,” etc., or using negative limiting terms when reciting claim elements. Terms such as “preferred,” “ideally,” “preferred,” “optionally,” “may,” and similar terms are used to indicate that the referred item, condition, or step is an optional (non-essential) feature.

[0040] Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” include plural references. The term “and / or” means any one, any combination, or all of the associated items. The phrase “one or more” is readily understood by those skilled in the art, especially when read in its context of use.

[0041] The term "about" can refer to a variation of ±5%, ±10%, ±20%, or ±25% of a specified value. For example, in some embodiments, "about 50%" can have a variation of 45% to 55%. For integer ranges, the term "about" can include being one or two integers larger and / or smaller than the stated integer at each endpoint of the range. Unless otherwise stated herein, the term "about" is intended to include ranges and values ​​adjacent to the stated range that are functionally equivalent in relation to the composition or embodiment.

[0042] As those skilled in the art will understand, for any and all purposes, particularly in the provision of a written description, all ranges described herein also encompass any and all possible subranges and combinations thereof, as well as the individual values ​​constituting the range, particularly integer values. The described range includes every specific value, integer, decimal, or entity within that range. Any listed range can be readily recognized as sufficiently described and enabling the decomposition of the range into at least two equal halves, thirds, quarters, fifths, or tenths. As a non-limiting example, each range discussed herein can be readily decomposed into a lower third, a middle third, and an upper third, etc.

[0043] As those skilled in the art will also understand, all language such as “up to,” “at least,” “greater than,” “less than,” “more than,” “or more,” etc., includes the numbers described, and such terms refer to ranges that can subsequently be broken down into subranges as described above. In the same manner, all ratios described herein also include all sub-ratios falling within a wider range.

[0044] In some embodiments, the various components of the hinge can be manufactured using various methods, such as stamping, forging, and casting. In other embodiments, the various components of the hinge can be made of various types of materials, such as metals and plastics. In some embodiments, a lubricant or a material impregnated with a lubricant can be used.

[0045] Those skilled in the art will understand that there are many other possible alternative implementations and modifications, and that the examples above are merely illustrative of one or more implementations. Therefore, the scope is limited only by the appended claims.

Claims

1. An electrically conductive overmolded bushing used in an automotive hinge connection, comprising: Electrically conductive, carbon fiber-filled polymer composite material; At least one of the at least two metal hinge segments to be connected is a steel hinge segment, wherein the at least one steel hinge segment is provided with a pivot pin hole. The polymer composite material is overmolded into the pivot pin hole to form a bushing; The bushing has a circumferential flange extending radially from the pivot pin hole; Each of the circumferential flanges is provided with at least one circumferential rib; and The bushing also has an inner cylindrical wall, which is integral with the circumferential flange and abuts against the pivot pin hole; This allows the carbon fibers in the bushing to be exposed during the assembly of the hinge by compressing the at least one circumferential rib, thereby establishing an electrical connection between the at least two metal hinge segments.

2. The electrically conductive coated bushing used in the connection portion of an automotive hinge as described in claim 1, wherein, The polymer composite material is neither PFAS nor PTFE.

3. The electrically conductive overmolded bushing used in the connection portion of an automotive hinge as described in claim 1 or 2, wherein, Each of the circumferential flanges is provided with multiple circumferential ribs.

4. The electrically conductive overmolded bushing used in the connection portion of an automotive hinge according to any one of claims 1 to 3, wherein, The inner cylindrical wall is provided with at least one longitudinal rib.

5. The electrically conductive overmolded bushing used in the connection portion of an automotive hinge according to any one of claims 1 to 4, wherein, The inner cylindrical wall is provided with multiple longitudinal ribs.

6. The electrically conductive overmolded bushing used in the connection portion of an automotive hinge according to any one of claims 1 to 5, wherein, The polymer composite material used for the bushing is a lubricated polyamide 4 / 6 containing 30% carbon fiber.

7. The electrically conductive overmolded bushing used in the connection portion of an automotive hinge according to any one of claims 1 to 6, wherein, The at least two metal hinge sections comprise steel.

8. A method for forming an electrically conductive overmolded bushing used in an automotive hinge connection, comprising: a) Overmolding an electrically conductive, carbon fiber-filled polymer composite material into the pivot pin hole of the first metal hinge section to form a bushing; b) During overmolding, at least one circumferential rib is integrally formed on each of two opposite circumferential flanges extending radially from the pivot pin, and the inner cylindrical wall of the bushing is integrally formed. as well as c) Rivet the pivot pin through the bushing to rotatably connect the first metal hinge section to the second metal hinge section; d) The riveting causes compression of at least one of the circumferential ribs to expose the carbon fiber and establish an electrical connection between the first metal hinge segment and the second metal hinge segment through the bushing.

9. The method according to claim 8, wherein, Multiple circumferential ribs are formed in each of the circumferential flanges.

10. The method according to claim 8 or 9, wherein, At least one longitudinal rib is formed on the inner cylindrical wall.

11. The method according to any one of claims 8 to 10, wherein, Multiple longitudinal ribs are formed on the inner cylindrical wall.

12. The method according to any one of claims 8 to 11, wherein, The polymer composite material is neither PFAS nor PTFE.

13. The method according to any one of claims 8 to 12, wherein, The polymer composite material of the bushing comprises lubricated polyamide 4 / 6 containing 30% carbon fiber.

14. The method according to any one of claims 8 to 13, wherein, The first metal segment and the second metal segment comprise steel.

Images