Low-squeak compliant pivot joint

Abstract

A compliant pivot joint for rotationally coupling a link member to a frame member in a vehicle seat is provided. The compliant pivot joint includes a cup-shaped protrusion formed on the link member with a cup-shaped opening, a shoulder bolt having a first shaft portion protruding from a bolt head and terminating in a shoulder, a biasing member having an offset opening, and a fastener fixedly coupled to the frame member. The shoulder bolt is fixedly coupled to the fastener and extends through the offset opening and through the cup-shaped opening. The biasing member is spaced between the cup-shaped protrusion and the bolt head and biases the bolt head away from the cup-shaped protrusion. A curved shoulder surface of the fastener frictionally engages the cup-shaped protrusion, and a shoulder of the shoulder bolt frictionally engages an end surface of the fastener.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and all benefits of U.S. Provisional Application No. 63 / 054,819, filed on July 22, 2020, and entitled “Low Chuck Compliant Pivot Joint,” the disclosure of which is hereby incorporated by reference in its entirety. Background of the Invention Technical Field

[0004] The present invention relates to a pivot joint connecting two components of a vehicle seat. More particularly, the present invention relates to a low-squeak, compliant pivot joint that rotationally couples a pivot link to a frame member of a vehicle seat. Background Art

[0006] 2. Description of the Prior Art

[0007] Many vehicle seats are capable of being repositioned between two or more positions. Typically, a vehicle seat includes a seat back rotatably coupled to a seat cushion frame, wherein the seat cushion frame is pivotally coupled to a seat base. In some seats, the seat cushion frame is rotatably coupled to the seat base by one or more pivot links. Each pivot link is rotatably coupled to the seat cushion frame at one end by a first pivot joint and rotatably coupled to the seat base at an opposite end by a second pivot joint. Movement of the pivot links repositions the seat cushion frame between various positions.

[0008] Typically, pivot joints include an inherent amount of lateral play within the pivot joint to allow for rotation of the pivot joint. Additionally, radial loads can deform the pivot joint and cause wear over time, which increases perceived radial looseness. Furthermore, lateral play is required for assembly and tolerance stack-up accommodation. In a typical pivot joint, such as a bushing pivot joint, lateral play within the pivot joint contributes to the overall perceived looseness associated with the pivot joint.

[0009] Sometimes, fore-aft and / or side loads are applied to the vehicle seat. The fore-aft and / or side loads may cause the pivot joint to rattle or move suddenly in response to the applied load. Unfortunately, the rattle of the pivot joint may be perceived as looseness in the pivot joint, resulting in a perceived defect in the vehicle seat. Additionally, lateral play within the pivot joint may result in unacceptable buzz, squeak and rattle (BSR) noises when the vehicle seat is subjected to road vibrations. Both the perceived looseness in the pivot joint and the noticed buzz, squeak and rattle (BSR) noises may result in noise complaints.

[0010] It is desirable to limit perceived looseness in a pivot joint of a vehicle seat in response to applied fore-aft and side loads. In addition, it is desirable to maintain sufficient lateral clearance in the pivot joint to maintain rotational friction within a target range. In addition, it is desirable for the pivot joint to have a low amount of rattle in response to applied fore-aft and side loads. In addition, it is desirable to reduce the likelihood of buzzing, squeaking and rattling noises associated with the pivot joint. Summary of the invention

[0011] The present invention relates to a compliant pivot joint for a vehicle seat that rotatably connects a link member to a frame member. The compliant pivot joint includes: a cup-shaped protrusion having a cup-shaped opening and formed in one of the link member and the frame member; a fastener having a curved shoulder surface, wherein the fastener is fixedly connected to the other of the link member and the frame member; a shoulder bolt having a first shaft portion protruding from a bolt head, wherein a shoulder extends from the first shaft portion and abuts against a second shaft portion; and a biasing member having a biasing opening. The shoulder bolt extends through the biasing opening and through the cup-shaped opening, wherein the shoulder bolt is fixedly connected to the fastener and the curved shoulder surface is frictionally engaged with a lower surface of the cup-shaped protrusion. The biasing member is spaced between the upper surface of the cup-shaped protrusion and the bolt head and biases the bolt head away from the cup-shaped protrusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Advantages of the present invention will be readily appreciated as they become better understood by referring to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0013] Figure 1 is a perspective view of a portion of a vehicle seat having a pivot link rotatably coupled to a seat cushion frame and a seat base via a low-squeeze compliant pivot joint according to one embodiment of the present invention;

[0014] Figure 2 yes Figure 1an enlarged perspective view of a portion 2 of the seat showing a pivot link coupled to a seat base and a seat cushion frame via a compliant pivot joint;

[0015] Figure 3 It is along Figure 2 A cross-sectional view taken along section line 3-3 of FIG. 1 showing a compliant pivot joint abutting the pivot link to the seat cushion frame and the seat base;

[0016] Figure 4 yes Figure 3 an enlarged view of a portion 4 of the seat showing a compliant pivot joint abutting the pivot link to the seat base;

[0017] Figure 5 is an exploded view of a compliant pivot joint abutting a pivot link to a seat frame member according to a second embodiment of the present invention;

[0018] 6 is an enlarged perspective view of a known seat assembly having a pivot link rotationally coupled to a seat cushion frame and a seat base via a known bushing pivot joint;

[0019] 7 is an enlarged cross-sectional view of the known bushing pivot joint of FIG. 6 taken along section line 7-7 of FIG. 6 , illustrating lateral clearance within the bushing pivot joint;

[0020] Figure 8 yes Figure 4 an enlarged cross-sectional view of a portion 8 of FIG. 8 showing the compliant pivot joint in an unloaded state;

[0021] Fig. 9 yes Figure 4 an enlarged cross-sectional view of a portion 8 of FIG. 8 showing the compliant pivot joint in a loaded state;

[0022] Fig.10 is a cross-sectional view of a conical washer according to one embodiment of the present invention;

[0023] Fig.11 is a cross-sectional view of an exemplary spring disk stack including a combination of stacked conical washers according to an embodiment of the present invention;

[0024] Fig.12 is a cross-sectional view of a low-squeeze compliant pivot joint according to a third embodiment of the present invention;

[0025] Fig.13 is a perspective view of a portion of a vehicle seat having a pivot link rotatably coupled to a seat cushion frame and a seat base via a compliant pivot joint connected by a leaf spring according to a fourth embodiment of the present invention;

[0026] Fig.14 yes Fig.13 an enlarged perspective view of a portion 14 of the seat frame showing a pivot link coupled to a seat base and a seat cushion frame via a compliant pivot joint connected by a leaf spring;

[0027] Fig.15 It is along Fig.14 A cross-sectional view taken along section line 15-15 of FIG. 1 showing a leaf spring bridging a compliant pivot joint adjoining the pivot link to the seat cushion frame and the seat base;

[0028] Fig.16 yes Fig.15 an enlarged view of portion 16 of , showing the leaf spring biasing the bolt head away from the pivot link;

[0029] Fig.17 is an exploded view of a compliant pivot joint abutting the pivot link to the seat base and seat cushion frame according to a fifth embodiment of the present invention;

[0030] Fig.18 It is along Fig.14 The section line 15-15 is taken Fig.14 A cross-sectional view of a compliant pivot joint and a leaf spring showing an unconstrained profile and a constrained profile of the leaf spring; and

[0031] Fig.19 Picture shows Fig.18 A cross-sectional view of a compliant pivot joint and leaf spring illustrating the spring load created by deforming the leaf spring during assembly. DETAILED DESCRIPTION

[0032] The present disclosure relates to a pivot joint in a vehicle seat. Specifically, the present disclosure relates to a low-squeeze, compliant pivot joint that rotationally couples a pivot link to a frame member of the vehicle seat and includes a biasing member that minimizes undesired fore-aft and lateral movement of the pivot link relative to the frame member. Figures 1 to 5 and Figures 8 to 19 An exemplary low-sounding compliant pivot joint that rotationally couples a pivot link to other components of a vehicle seat according to embodiments described herein is illustrated. Directional designations such as top, bottom, upper, lower, upward, downward, longitudinal, lateral, left, right, etc., used or shown in the specification, drawings, or claims are relative terms used for ease of description and are not intended to limit the scope of the invention in any respect. Referring to the drawings, like reference numerals indicate like or corresponding parts throughout the several views.

[0033] Figure 1 A perspective view of a portion of a vehicle seat 20 is shown showing the seat cushion frame 24 rotatably coupled to the seat base 28 via the rear pivot link 32. In certain embodiments, the seat cushion frame 24 is rotatably coupled to the right-hand seat base 28 and the left-hand seat base 28' via the right-hand rear pivot link 32 and the left-hand rear pivot link 32' and optionally via the right-hand front pivot link 36 and the left-hand front pivot link 36'. Figure 1 , an upper compliant pivot joint 40 extends through the rear pivot link 32 near its upper end 32A and rotatably couples the rear pivot link 32 to the seat cushion frame 24. Similarly, a lower compliant pivot joint 42 extends through the rear pivot link 32 near its lower end 32B and rotatably couples the rear pivot link 32 to the seat base 28. The upper compliant pivot joint 40 and the lower compliant pivot joint 42 are low-sounding compliant pivot joints 40, 42, as described in more detail below as compliant pivot joints 40, 42.

[0034] Compared to the known bushing pivot joint 44 shown in FIGS. 6 and 7 , Figures 1 to 4 The compliant pivot joints 40, 42 shown in FIG. 4 reduce perceived looseness. Figure 2 and Figure 3 An enlarged perspective view and a cross-sectional view of the compliant pivot joints 40 , 42 rotatably coupling the rear pivot link 32 to the seat cushion frame 24 and the seat base 28 are shown, respectively. Figure 4 An enlarged cross-sectional view of the lower compliant pivot joint 42 is shown. Figure 2 and Figure 3 , the upper compliant pivot joint 40 is constructed in a similar manner to the lower compliant pivot joint 42. In certain embodiments, the upper compliant pivot joint 40 and the lower compliant pivot joint 42 may have different configurations. It will be appreciated that one or more of the rear pivot links 32, 32' and the front pivot links 36, 36' may be rotatably coupled to one or more seat components, such as the seat cushion frame 24 and the seat base 28 as non-limiting examples, via the compliant pivot joint 40, 42. Additionally, it will be appreciated that the compliant pivot joint 40, 42 may rotatably attach any type of link member and / or frame member to another seat component including a bracket, other frame member, a pivotable link, etc., as desired for a particular application.

[0035] Figure 3 and Figure 4The compliant pivot joint 40, 42 shown in FIG. 4 includes a spline nut 46 that is fixedly coupled to an aperture 48 in each of the seat cushion frame 24 and the seat base 28. The spline nut 46 has a generally cylindrical shape having an outer wall 46A extending between a first end wall 46B and a second end wall 46C. Alternatively, as a non-limiting example, the outer wall 46A may be formed by a plurality of generally flat sides forming a polygonal barrel, such as a hexagonal barrel, a tapered hexagonal barrel, an octagonal barrel, or the like. Additionally, the spline nut 46 includes an internally threaded passage 50 that extends between the first end wall 46B and the second end wall 46C and is configured to engage in a meshing manner with the external threads 54 on the shoulder bolt 58. A curved shoulder surface 62 extends between the outer wall 46A and the second end wall 46C of the spline nut 46. The curved shoulder surface 62 is generally described by a first radius of curvature 62R. The spline nut 46 generally includes a rivet feature 66 near the first end wall 46B that is configured to frictionally and / or crimpably engage with an aperture 48 in the seat cushion frame 24 or the seat base 28. It will be understood that while the spline nut 46 is shown and described in the drawings, other types, sizes, and shapes of threaded fasteners, such as loose nuts, push nuts, swaged nuts, weld nuts, etc., may be used without changing the scope of the present invention. For example, Fig.12 An alternative embodiment is shown in which a loose nut 68 is threaded onto a shoulder bolt 70 .

[0036] Figure 3 and Figure 4The shoulder bolt 58 of the compliant pivot joint 40, 42 shown in FIG. 4 includes a generally cylindrically shaped shaft 74 that extends from a lower surface 76' of a bolt head 76, is aligned with a longitudinal axis 58' of the shoulder bolt 58, and terminates at a shaft end 78. The shaft 74 includes a first shaft portion 74A extending between the bolt head 76 and a second shaft portion 74B. The first shaft portion 74A is generally cylindrical in shape and has an outer wall 74A-1 extending between the bolt head 76 and the first shaft portion end wall 74A-2. The maximum outer diameter of the outer wall 74A-1 of the first shaft portion 74A is less than the minimum outer diameter of the bolt head 76. In addition, the first shaft portion 74A is sized and shaped such that at least a portion of the first shaft portion 74A will pass through an opening 82 in the rear pivot link 32. In addition, the bolt head 76 is sized and shaped such that the bolt head 76 cannot pass through the opening 82 in the rear pivot link 32. More specifically, the minimum outer diameter of the bolt head 76 is greater than the maximum inner diameter of the opening 82 in the rear pivot link 32. The second shaft portion 74B is also generally cylindrical in shape, having an outer wall 74B-1 extending between the first shaft portion end wall 74A-2 and the shaft end 78 of the shoulder bolt 58. The maximum outer diameter of the outer wall 74B-1 of the second shaft portion 74B is less than the minimum outer diameter of the first shaft portion 74A. The first shaft portion end wall 74A-1 defines a shoulder 80 in the shoulder bolt 58. The second shaft portion 74B includes external threads 54 that are sized and shaped to engage in meshing engagement with the internally threaded passage 50 of the spline nut 46. As shown in FIG. Figure 4 As shown in FIG. 8 , the shoulder 80 of the shoulder bolt 58 abuts the second end wall 46C of the spline nut 46 when the shoulder bolt 58 and the spline nut 46 are assembled together.

[0037] Reference Figures 2 to 4 , the rear pivot link 32 extends between opposite upper and lower ends 32A, 32B, wherein a cup-shaped protrusion 90 extends from a main portion 94 of the rear pivot link 32, aligned with each of the compliant pivot joints 40, 42. Although the main portion 94 of the rear pivot link 32 is Figure 2 94A, but the rear pivot link 32 may have any size and shape suitable for a particular application without changing the scope of the invention. Figure 4 , the opening 82 in the rear pivot link 32 has a center point that is aligned with the longitudinal axis 58' of the shoulder bolt 58 when the rear pivot link 32 is assembled as part of the compliant pivot joint 40, 42. The cup-shaped protrusion 90 is also centered on the longitudinal axis 58', with the opening 82 passing through the cup-shaped protrusion 90. Figure 4, the cup-shaped protrusion 90 includes a curved portion 98 having a second radius of curvature 98R and optionally includes a generally flat portion 102 around the circumference of the opening 82. The first radius of curvature 62R of the curved shoulder surface 62 of the spline nut 46 and the second radius of curvature 98R of the curved portion 98 of the cup-shaped protrusion 90 are selected so that the curved shoulder surface 62 interacts with the curved portion 98 at a desired pressure angle. In one embodiment, the cup-shaped protrusion 90 includes a curved portion 98 having a second radius of curvature 98R of about 1.8 mm, a flat portion 102 of about 1.5 mm, an opening 82 in the rear pivot link 32 having an inner diameter of about 15 mm, and an overall height of about 5.8 mm between the flat portion 102 and the main portion 94 of the rear pivot link 32. The outer wall 46A of the spline nut 46 has an outer diameter of about 21.75 mm, wherein the first radius of curvature 62R of the curved shoulder surface 62 is about 1.2 mm. It will be appreciated that the specific dimensions, sizes, materials and shapes of the components forming the compliant pivot joints 40, 42 may be varied, including but not limited to the addition of additional components, without changing the scope of the present invention.

[0038] Additionally, it will also be understood that, without changing the scope of the present invention, in certain embodiments, when the compliant pivot joints 40, 42 rotationally couple the rear pivot link 32 to the seat cushion frame 24, the cup-shaped protrusion 90 may be formed in one of the rear pivot link 32 and the seat cushion frame 24, wherein the spline nut 46 is fixedly coupled to the other of the rear pivot link 32 and the seat cushion frame 24. The same option also applies when the compliant pivot joints 40, 42 rotationally couple any pivot link 32, 32', 36, 36' to any other frame member, the seat cushion frame 24 and the seat base 28 being non-limiting examples. Figure 3 and Figure 4 In the embodiment shown in FIG. 1 , the rear pivot link 32 includes a cup-shaped protrusion 90, wherein the spline nut 46 is fixedly coupled to the seat cushion frame 24 and the seat base 28. However, in alternative embodiments, the cup-shaped protrusion 90 may be included in a frame member, wherein the spline nut 46 is fixedly coupled to the rear pivot link 32. In addition, some embodiments include a loose nut 68 that is meshingly coupled to the shoulder bolt 70, while the loose nut 68 is not fixedly coupled to the rear pivot link 32 or the frame member, such as in FIG. Fig.12 The embodiments shown in FIG.

[0039] exist Figure 3 and Figure 4In the embodiment shown in FIG. 1 , a biasing member 114 is assembled between the lower surface 76′ of the bolt head 76 and the cup-shaped protrusion 90 of the rear pivot link 32. The biasing member 114 is captured between the bolt head 76 and the cup-shaped protrusion 90 when the shoulder bolt 58 is engaged with the spline nut 46. One embodiment of the biasing member 114 is a stack 118 of conical washers 122. Fig.10 A single exemplary conical washer 122 is shown in FIG. Fig.11 An exemplary stacking pattern 118A-118E of conical washers 122 is shown in FIG. Fig.10 The conical washer 122 is a disc-shaped washer that includes opposing upper and lower surfaces 132, 132' and an outer edge surface 136 extending between the opposing upper and lower surfaces 132, 132', wherein a hole 140 passing between the opposing upper and lower surfaces 132, 132' is aligned with the longitudinal axis 122A of the conical washer 122. The upper surface 132 is generally convex in shape, while the lower surface 132' is generally concave in shape. An exemplary conical washer 122 has an outer diameter of approximately 26 mm, a minimum thickness of approximately 0.6 mm between the opposing upper and lower surfaces 132, 132', a maximum axial distance of approximately 1.4 mm between the opposing upper and lower surfaces 132, 132', and an inner diameter of the hole 140 of approximately 13.6 mm. As non-limiting examples, suitable conical washers 122 are formed of high carbon steel, alloy steel, stainless steel, heat treated steel, tempered steel, etc.

[0040] exist Fig.11 1 shows an exemplary stacking pattern 118A-118E of the stack of conical washers 122. The stack of conical washers 122 118 is alternatively described as a spring disk stack 118 below. Fig.11 , spring disk stack 118A includes two conical washers 122 stacked in series. The conical washers 122 are stacked in series when the upper surface 132 of the first conical washer 122 abuts the upper surface 132 of the second conical washer 122. Conversely, spring disk stack 118B illustrates two conical washers 122 stacked in parallel, wherein the lower surface 132' of the first conical washer 122 abuts the upper surface 132 of the second conical washer 122. Spring disk stacks 118C and 118D respectively illustrate three conical washers 122 and four conical washers 122 stacked in series. Spring disk stack 118E illustrates a stack of eight conical washers 122 stacked in a combination of parallel and series. The number, stacking pattern, size, and material of the selected stack 118 of conical washers 122 suitable for a particular application are based in part on the application to the vehicle seat 20 ( Figure 1The amount of expected fore-aft load 144' and side load 148' as shown in FIG. 1 and the specific dimensions of the components within the compliant pivot joints 40, 42 are determined.

[0041] exist Figure 3 and Figure 4 The spring disk stack 118 shown in can be adjusted based on the range of lateral compensation required to account for different amounts of expected lateral tolerance changes. In certain embodiments, the axial compliance distance that the spring disk stack 118 is able to overcome to prevent rattling is balanced by a biasing force B1 applied by the spring disk stack 118 within the compliant pivot joint 40, 42 to minimize the rotational force used to rotate the compliant pivot joint 40, 42. Therefore, in some embodiments of the compliant pivot joint 40, 42, in order to maintain rotational friction within a target range, when the applied load 144', 148' is above a predetermined target range, the selected spring disk stack 118 configuration will not be sufficient to prevent rattling. Generally, the compliant pivot joint 40, 42 is configured to prevent and / or reduce the tendency to rattle when the load 144', 148' applied in the fore-aft direction 144 and the lateral direction 148 reaches a predetermined amount, while maintaining the rotational force less than a predetermined target. In Figure 3 and Figure 4 The compliant pivot joints 40, 42 shown in the drawings are designed to provide compliance to accommodate up to + / - 3 degrees of link rotation and dimensional variations in the components of the vehicle seat 20. In addition, the rotational friction of the compliant pivot joints 40, 42 is preferably designed to be less than about 1 Nm. It will be appreciated that the compliant pivot joints 40, 42 can be configured to accommodate the range of angles of link rotation by varying the number of tapered washers and the stacking pattern of the tapered washers and the size and shape of the various components within the compliant pivot joints 40, 42 without changing the scope of the present invention.

[0042] Figure 3 and Figure 4 A preferred embodiment is shown including a spring disk stack 118C comprising three conical washers 122 assembled in series. Fig.12As shown in the second preferred embodiment, a spring disk stack 118A includes two conical washers 122 assembled in series. However, it will be understood that the spring disk stack 118 may include any combination of the number and stacking pattern of the conical washers 122 without changing the scope of the present invention. As non-limiting examples, the conical washers 122 are alternatively described as spring washers, Belleville washers, disc springs, conical spring washers, cup spring washers, etc. It will be understood that the size, material, and shape of the conical washers 122 may be varied without changing the scope of the present invention, including, as non-limiting examples, using spring washers of other shapes, such as curved spring washers, wave spring washers, Spring washers, multi-wave compression spring washers, finger spring washers, poly-wave compression Belleville springs, etc. Furthermore, it will be appreciated that the spring disc stack 118 may include spring washers of one or more types, sizes, shapes, and materials without altering the scope of the present invention.

[0043] Figure 5 Shows Figure 1 An exploded view of another embodiment of the compliant pivot joint 40. For simplicity, Figure 5 Medium and above Figures 2 to 4 Elements that are the same or similar to the elements used in the embodiments shown in FIG. 1 have the same reference numerals. Figures 2 to 4 As in the first embodiment shown in FIG. Figure 5 The compliant pivot joint 40 shown in FIG. 4 includes a shoulder bolt 58, a biasing member 114 including a spring disk stack 118 of three conical washers stacked in series, a rear pivot link 32, a spline nut 46, and a seat cushion frame 24. The rear pivot link 32 includes an optional recessed channel 152 extending around the outer periphery 90′ of the cup-shaped protrusion 90. Due to the recessed channel 152, the upper surface 90A of the cup-shaped protrusion 90 can be flush with the main portion 94 of the rear pivot link 32, raised above the main portion 94 of the rear pivot link 32, or recessed below the main portion 94 of the rear pivot link 32 without changing the scope of the present invention.

[0044] exist Figure 5During assembly of the embodiment shown in , the rivet feature 66 of the spline nut 46 is assembled with the seat cushion frame 24 such that the internally threaded passage 50 of the spline nut 46 is aligned with the aperture 48 in the seat cushion frame 24. In an alternative embodiment, a weld nut replaces the spline nut 46, wherein the weld nut is welded to the seat cushion frame 24. The end 78 of the shoulder bolt 58 passes through the hole 140 in the tapered washer 122 and through the opening 82 in the rear pivot link 32. When the end 78 of the shoulder bolt 58 is aligned with the internally threaded passage 50 in the spline nut 46, the shoulder bolt 58 is rotated so that the external threads 54 of the shoulder bolt 58 engage the internally threaded passage 50 of the spline nut 46 in a meshing manner. When fully assembled, the shoulder 80 of the shoulder bolt 58 frictionally engages the second end wall 46C of the spline nut 46, such as Figure 4 In addition, when the shoulder bolt 58 is fully assembled with the spline nut 46, the curved shoulder surface 62 of the spline nut 46 frictionally engages the cup-shaped protrusion 90 in the rear pivot link 32. During assembly, the grease 156 ( Figure 4 ) is optionally added between the cup-shaped protrusion 90 and the curved shoulder surface 62 of the spline nut 46 to reduce friction between the rear pivot link 32 and the spline nut 46. The spring disk stack 118 biases the bolt head 76 away from the rear pivot link 32 and keeps the curved shoulder surface 62 of the spline nut 46 in frictional engagement with the cup-shaped protrusion 90 of the rear pivot link 32.

[0045] and Figures 1 to 5 In contrast to the compliant pivot joints 40, 42 shown in FIG. 6 and FIG. 7, exemplary known bushing pivot joints 44, 44' are shown. For simplicity, FIG. 6 and FIG. 7 are similar to the above FIG. Figures 1 to 5 6 shows a pivot link 32P rotatably coupled to the seat cushion frame 24 and the seat base 28 via a known upper bushing pivot joint 44 and a lower bushing pivot joint 44'. A cross-sectional view of the known upper bushing pivot joint 44 is shown in FIG. 7. Referring to FIG. 7, the known bushing pivot joint 44 includes a shoulder bolt 170, a pivot link 32P, a nut 174, and the seat cushion frame 24.

[0046] 6 and 7, the pivot link 32P has an elongated shape including a generally flat main portion 94P and curved side portions 190 protruding from the main portion 94P. Although known pivot links 32P may vary in size, shape, and profile, generally known pivot links 32P include a generally flat section 191 surrounding an opening 82P in the known pivot link 32P.

[0047] As shown in FIG. 7 , the opening 82P in the pivot link 32P is lined with a bushing 192 as is generally known in the art. The bushing 192 is generally annular with a passage 192' extending axially through the bushing 192. Typically, the bushing 192 comprises a metallic material such as steel and / or a plastic material. The bushing 192 reduces radial looseness between the shoulder bolt 170 and the opening 82P in the pivot link 32P and controls friction. However, a press is required to install the steel bushing 192 into the opening 82P of the pivot link 32P. Additionally, the plastic bushing 192 has retention issues.

[0048] 6 and 7 include a first frame member 24A and a second frame member 24B. Each of the first frame member 24A and the second frame member 24B includes an aperture 48 that aligns with a known bushing pivot joint 44, 44'.

[0049] In the known bushing pivot joint 44 shown in FIG. 7 , the shoulder bolt 170 has a generally cylindrically shaped shaft 200 that protrudes from a bolt head 202, is aligned with the longitudinal axis 170A of the shoulder bolt 170, and terminates at a shaft end 204. The shaft 200 generally includes a first shaft portion 200A, a second shaft portion 200B, and a third shaft portion 200C. The first shaft portion 200A is generally cylindrical in shape, wherein an outer wall 200A-1 extends between the bolt head 202 and the first shaft portion end wall 200A'. The outer diameter of the outer wall 200A-1 of the first shaft portion 200A is smaller than the outer diameter of the bolt head 202. Typically, the outer diameter of the bolt head 202 is generally larger than the inner diameter of the aperture 48 in the seat cushion frame 24. This prevents the bolt head 202 from passing through the aperture 48 in the seat cushion frame 24. Additionally, the first shaft portion 200A is sized and shaped such that at least a portion of the first shaft portion 200A will pass through the aperture 48 in the seat cushion frame 24 .

[0050] Referring to the known bushing pivot joint 44 shown in FIG7 , the second shaft portion 200B is generally cylindrical in shape, wherein an outer wall 200B-1 extends between the first shaft portion end wall 200A' and the second shaft portion end wall 200B'. In addition, the outer diameter of the outer wall 200B-1 is selected so that at least a portion of the second shaft portion 200B will pass through the passage 192' in the bushing 192. In the exemplary known embodiment shown in FIG7 , the outer diameter of the second shaft portion 200B is smaller than the outer diameter of the first shaft portion 200A, wherein the end wall 200A' extends between the second shaft portion 200B and the first shaft portion 200A to define a first shoulder 208.

[0051] Also shown in FIG. 7 is a third shaft portion 200C extending from the second shaft portion end wall 200B' of the shoulder bolt 170. Generally, the third shaft portion 200C has a generally cylindrical shape, wherein an outer surface 200C-1 includes external threads configured to meshingly engage with an internally threaded passage 210 in the nut 174. Additionally, the outer diameter of the outer surface 200C-1 is smaller than the outer diameter of the second shaft portion 200B, wherein the end wall 200B' extends between the third shaft portion 200C and the second shaft portion 200B to define a second shoulder 214. When the nut 174 is assembled with the shoulder bolt 170, the base surface 174' of the nut 174 abuts the second shoulder 214 of the shoulder bolt 170.

[0052] 7 is formed by passing the shaft end 204 of the shoulder bolt 170 through the aperture 48 in the seat cushion frame 24 and through the passage 192' in the bushing 192, wherein the bolt head 202 abuts the seat cushion frame 24. The nut 174 is aligned with the third shaft portion 200C of the shoulder bolt 170 and threaded onto the shaft end 204 until the base surface 174' of the nut 174 frictionally engages the second shoulder 214.

[0053] During operation, the pivot link 32P rotates about the known bushing pivot joint 44 shown in FIG. 7. A lateral clearance 218 is provided between the base surface 174' of the nut 174 and the bushing 192, and between the bushing 192 and the first shoulder 208 of the shoulder bolt 170 to allow the pivot link 32P to rotate. If the base surface 174' of the nut 174 and the first shoulder 208 of the shoulder bolt 170 were in direct contact with the bushing 192, the rotation of the pivot link 32P may be limited. Therefore, the first shoulder 208 and the second shoulder 214 are spaced apart a distance in the axial direction 170A that is greater than the axial width of the bushing 192 to allow the pivot link 32P to rotate freely. Therefore, an inherent lateral clearance 218 is included in the known bushing pivot joint 44 to limit the amount of friction in the known bushing pivot joint 44. Furthermore, lateral clearance 218 is included to prevent friction caused by dimensional variations between the seat cushion frame 24, the seat base 28, and the rails attached to the seat base 28. Additionally, radial loads may cause deformation of the bushing 192, which may increase perceived radial looseness.

[0054] When the front and rear loads 144 'and / or lateral loads 148 'are applied to the vehicle seat 20, the lateral gap 218 in the known bushing pivot joint 44 of FIG. 7 may cause the seat cushion frame 24 to move in the front-rear direction 144 and the lateral direction 148 ( Figure 1). Loads 144', 148' applied to the vehicle seat 20 in the fore-aft direction 144 and / or the lateral direction 148 may cause the bushing pivot joints 44, 44' to deflect under the load. Movement, deflection, and / or rattle of the vehicle seat 20 in the fore-aft direction 144 and / or the lateral direction 148 when the loads 144', 148' are applied to the vehicle seat 20 may be perceived as looseness in known bushing pivot joints 44, 44'. The perceived looseness in the bushing pivot joints 44, 44' may be considered objectionable based in part on the magnitude of the perceived looseness. Radial loads on the bushing pivot joints 44, 44' may cause deformation and degradation of the bushing 192, wherein the radial looseness subsequently increases over time. The inherent lateral play 218 combined with increased play due to degradation of the bushings 192 in the bushing pivot joints 44 , 44 ′ may result in buzz, squeak and rattle (BSR) noises when the vehicle seat 20 vibrates as the vehicle travels along a road surface.

[0055] Compared to the typical bushing pivot joints 44, 44' shown in Figures 6 and 7, for example Figures 1 to 5 The compliant pivot joints 40, 42 shown in FIG. 1 minimize perceived looseness. When loads 144', 148' are applied to the vehicle seat 20 in the fore-aft direction 144 and / or the lateral direction 148, the perceived deflection of the compliant pivot joints 40, 42 is less than the perceived deflection of known bushing pivot joints 44, 44'. Even though the compliant pivot joints 40, 42 include lateral play between the bolt head 76 and the rear pivot link 32 to allow for a certain amount of lateral rotation of the rear pivot link 32, the biasing member 114 reduces the perception of rattle because there is always a biasing force B1 applied between the bolt head 76 and the rear pivot link 32, as shown in FIG. 1 . Figure 4 The biasing force B1 also urges the curved shoulder surface 98 toward the cup-shaped protrusion 90 by being fixedly coupled to the spline nut 46 via the shoulder bolt 58. Thus, the biasing member 114 reduces buzz, squeak and rattle (BSR) noises associated with the compliant pivot joints 40, 42 because the biasing member 114 continuously applies the biasing force B1 within the compliant pivot joints 40, 42.

[0056] Preferably, both pivot joints 40, 42 attaching the rear pivot link 32 to the other frame members are compliant pivot joints 40, 42, such as Figures 1 to 5. The biasing member 114, the cup-shaped protrusion 90, and the curved shoulder surface 62 of the spline nut 46 allow the compliant pivot joints 40, 42 to flex under load. Mixing compliant pivot joints 40, 42 and non-compliant pivot joints 44 (such as bushing pivot joints 44) within a single rear pivot link 32 is less than ideal because it may result in a reduced biasing force B1 and may result in perceived joint rattle. However, in certain embodiments, a single compliant pivot joint 40, 42 provides acceptable resistance to perceived rattle.

[0057] Figure 8 and Fig. 9 yes Figure 4 An enlarged view of portion 8 of compliant pivot joint 42 is shown in FIG. Figure 8 and Fig. 9 The illustration shows how the biasing member 114 between the bolt head 76 and the rear pivot link 32 combines with the cup-shaped protrusion 90 and the curved shoulder surface 62 on the spline nut 46 to reduce perceived looseness in the compliant pivot joint 42 . Figure 8 The compliant pivot joint 42 is shown in an unloaded state C1, wherein the shoulder bolt 58 is centered in the opening 82 through the rear pivot link 32, and wherein the spline nut 46 is centered in the cup-shaped protrusion 90. Figure 8 In the unloaded state C1 shown in FIG. 1 , there is an axial gap G1 between the second end wall 46C of the spline nut 46 and the opening 82 in the rear pivot link 32. The axial gap G1 is substantially uniform around the periphery of the opening 82 in the rear pivot link 32. In addition, the stack 118 of tapered washers 122 has a compressed axial height S1 that is substantially uniform around the periphery of the opening 82 in the rear pivot link 32.

[0058] Fig. 9 Picture shows Figure 8 The compliant pivot joint 42 when loads 144', 148' are applied in the fore-aft direction 144 and / or the lateral direction 148. More specifically, Fig. 9 One embodiment of the compliant pivot joint 42 in a loaded state C2 is shown. When the compliant pivot joint 42 is subjected to loads 144', 148' applied in the fore-aft direction 144 and / or the lateral direction 148, the rear pivot link 32 rotates relative to the shoulder bolt 58, causing the axial gaps G2, G3 between the second end wall 46C of the spline nut 46 and the opening 82 in the rear pivot link 32 to be non-uniform. This results in increased compression of the spring disk stack 118 on one side of the compliant pivot joint 42 compared to the opposite side, as shown in FIG. Fig. 94 and 5. The spring disk stack 118 can be compressed and / or expanded as needed to maintain a biasing force B1 that biases the spline nut 46 toward a position that engages the cup-shaped protrusion 90 in the rear pivot link 32. Preferably, the force provided by the spring disk stack 118 is high enough to prevent rattling within the compliant pivot joint 40, 42, but low enough to meet the rotational force target. In certain embodiments, the compliant pivot joint 40, 42 has a rotational friction designed to be less than about 1 Nm. It will be appreciated that the rotational friction may vary in other embodiments without changing the scope of the invention.

[0059] Additionally, when loads 144', 148' are applied to the compliant pivot joints 40, 42, the curved shoulder surface 62 of the spline nut 46 may rotate within the cup-shaped protrusion 90 of the rear pivot link 32, as shown. Fig. 9 As shown in Fig. 9 , the axial gap G2 between the upper surface 46C of the spline nut 46 and the opening 82 in the cup-shaped protrusion 90 on one side of the spline nut 46 is greater than the axial gap G3 on the opposite side of the spline nut 46. The curved shoulder surface 62 of the spline nut 46 remains in contact with the cup-shaped protrusion 90 in the rear pivot link 32 even if the rear pivot link 32 is moved from Figure 8 Because the biasing member 114 between the bolt head 76 and the cup-shaped protrusion 90 automatically expands and contracts to maintain the biasing force B1 on the shoulder bolt 58, the contact between the spline nut 46 and the cup-shaped protrusion 90 in the rear pivot link 32 is maintained even if the rear pivot link 32 has rotated.

[0060] Reference Figure 8 and Fig. 9 Since the biasing member 114 is compressed during assembly, the amount of compression of the biasing member 114 can vary within a range in which the biasing member 114 maintains the biasing force B1 on the compliant pivot joint 42. For example, Figure 8 and Fig. 9 A biasing member 114 is shown that includes a spring disk stack 118 formed by three conical washers 122 stacked in series. In some embodiments, multiple conical washers 122 are stacked and packaged together by shrink wrap for assembly purposes. The spring disk stack 118 provides compliance within the compliant pivot joints 40, 42.

[0061] There is less perceived looseness in the compliant pivot joints 40, 42 than in known bushing pivot joints 44, 44' because Fig. 9The biasing member 114 maintains contact between the spline nut 46 and the cup-shaped protrusion 90. In addition, the compliant pivot joints 40, 42 have less perceived rattle than the bushing pivot joints 44, 44' because the compliant pivot joints 40, 42 maintain contact between the spline nut 46 and the cup-shaped protrusion 90 even when the fore-aft load 144' and the side load 148' are applied to the vehicle seat 20. In addition, the biasing member 114 compensates for the wear of the components over time, thereby maintaining the biasing force B1 even after the components degrade. Because the compliant pivot joints 40, 42 are always biased by the biasing member 114, there is less buzz, squeak and rattle (BSR) noise associated with the compliant pivot joints 40, 42 than with typical bushing pivot joints 44, 44'. The compliant pivot joints 40, 42 are low friction and low rattle designs that can be used with any structural link joint. Additionally, the compliant pivot joints 40, 42 can replace existing bushing pivot joints 44, 44'.

[0062] Furthermore, it will be appreciated that although the cup-shaped projection 90 is shown as part of the rear pivot link 32, wherein the spline nut 46 is attached to the seat cushion frame 24 and the seat base 28, such as Figure 3 As illustrated, but without changing the scope of the present invention, in alternative embodiments, the cup-shaped protrusion 90 may be formed on any frame member, including but not limited to the seat cushion frame 24 and the seat base 28, wherein the spline nut 46 is fixedly coupled to the rear pivot link 32. In certain embodiments, the compliant pivot joints 40, 42 are configured such that one of the compliant pivot joints 40, 42 has the cup-shaped protrusion 90 on the rear pivot link 32, wherein the spline nut 46 is fixedly coupled to one of the seat cushion frame 24 and the seat base 28, and the other of the compliant pivot joints 40, 42 has the cup-shaped protrusion 90 as part of the other of the seat cushion frame 24 and the seat base 28, wherein the corresponding spline nut 46 is fixedly coupled to the rear pivot link 32. It will also be understood that the spline nut 46 may be replaced by a weld nut and other similar components without changing the scope of the present invention so long as the interface characteristics between the spline nut 46 and the cup-shaped protrusion 90 are maintained at the desired target pressure angle.

[0063] Fig.12 An alternative embodiment of the compliant pivot joints 40, 42 is shown. For simplicity, Fig.12 In and above Figures 1 to 4 Elements that are identical or similar to the elements used in the embodiments shown in FIG. 1 have the same reference numerals. Figure 4 The significant differences between the embodiments shown in FIG. Figures 1 to 4 As in the first embodiment shown in FIG. Fig.12 The compliant pivot joint 40 shown in FIG. 1 includes an opening 82 through the rear pivot link 32, an aperture 48 through the seat cushion frame 24, and a biasing member 114 including a spring plate stack 118. One substantial difference involves replacing the shoulder bolt 70 and loose nut 68 with an alternative shoulder bolt 70 and loose nut 68. Figure 4 The shoulder bolt 58 and the toothed nut 46 are provided. In addition, Figure 4 The curved shoulder surface 62 on the toothed nut 46 has been replaced by a curved shoulder surface 219 on the shoulder bolt 70. The curved shoulder surface 219 has a third radius of curvature 219R. Figure 4 The biasing member 114 is clamped between the bolt head 76 and the rear pivot link 32. Fig.12 The intermediate biasing member 114 is captured between the nut 68 and the rear pivot link 32 .

[0064] In more detail, Fig.12 The shoulder bolt 70 includes a generally cylindrical shaped shaft 220 that protrudes from a bolt head 224, is aligned with the longitudinal axis 70A of the shoulder bolt 70, and terminates at a shaft end 228. The shaft 220 includes a first shaft portion 220A, a second shaft portion 220B, and a third shaft portion 220C. The first shaft portion 220A is generally cylindrical in shape, wherein an outer wall 220A-1 extends between the bolt head 224 and the first shaft portion end wall 220A'. The outer diameter of the outer wall 220A-1 of the first shaft portion 220A is smaller than the outer diameter of the bolt head 224. In addition, a curved shoulder surface 219 extends between the outer wall 220A-1 of the first shaft portion 220A and the first portion end wall 220A'. The outer diameter of the bolt head 224 is generally larger than the inner diameter of the aperture 48 in the seat cushion frame 24. This prevents the bolt head 224 from passing through the aperture 48 in the seat cushion frame 24. Additionally, the first shaft portion 220A is sized and shaped such that at least a portion of the first shaft portion 220A will pass through the aperture 48 in the seat cushion frame 24 .

[0065] exist Fig.12 In the compliant pivot joint 40 shown in FIG. 1 , the second shaft portion 220B is generally cylindrical in shape, wherein an outer wall 220B-1 extends between the first shaft portion end wall 220A′ and the second shaft portion end wall 220B′. In addition, the outer diameter of the outer wall 220B-1 is selected so that at least a portion of the second shaft portion 220B will pass through the opening 82 in the rear pivot link 32. The outer diameter of the outer wall 220B-1 of the second shaft portion 220B is less than the outer diameter of the outer wall 220A-1 of the first shaft portion 220A. The first portion end wall 220A′ extending between the second shaft portion 220B and the first shaft portion 220A defines a first shoulder 230.

[0066] Fig.12 Also shown in the figure is a third shaft portion 220C extending from the second shaft portion end wall 220B' of the shoulder bolt 70. The third shaft portion 220C has a generally cylindrical shape, wherein an outer surface 220C-1 includes external threads configured to meshingly engage with internal threads 234 in the nut 68. In addition, the outer diameter of the outer surface 220C-1 is smaller than the outer diameter of the second shaft portion 220B, wherein the end wall 220B' extending between the third shaft portion 220C and the second shaft portion 220B defines a second shoulder 238.

[0067] Fig.12 The rear pivot link 32 has a cup-shaped protrusion 90 with a curved portion 98 whose radius of curvature 98R is selected so that the curved shoulder surface 219 of the shoulder bolt 70 interacts with the cup-shaped protrusion 90 at a desired pressure angle.

[0068] exist Fig.12 In the embodiment shown in FIG. 1 , the biasing member 114 is assembled on the shoulder bolt 70 between the rear pivot link 32 and the nut 68. When the nut 68 is screwed onto the shoulder bolt 70, the base surface 68' of the nut 68 abuts both the biasing member 114 and the second shoulder 238 of the shoulder bolt 70. Fig.12 1 is a spring disk stack 118 including two tapered washers 122 stacked in series. It will be appreciated that other combinations of tapered washers 122 and other types of biasing members 114 may be included as desired for a particular application. In some embodiments, the shoulder bolt 70 is welded to the seat cushion frame 24, the seat base 28, or other frame member. In other embodiments, the cup 90 may be included as part of the frame member, wherein the bolt head 224 is positioned adjacent the rear pivot link 32, the curved shoulder surface 219 of the shoulder bolt 70 abuts the curved surface 98 of the cup 90, and the biasing member 114 is captured between the nut 68 and the cup 90 in the frame member.

[0069] Figures 13 to 19 An alternative embodiment of the compliant pivot joint 40, 42 is shown including a leaf spring 260 as the biasing member 114. For simplicity, Figures 13 to 19 In and above Figures 1 to 4 Elements that are identical or similar to the elements used in the embodiments shown in FIG. 1 have the same reference numerals. Figures 1 to 4 One substantial difference involves replacing the biasing member 114 of the compliant pivot joints 40, 42 with a single leaf spring 260 extending between the compliant pivot joints 40, 42. More specifically, as Fig.13 As shown in Figure 3 and Figure 4 The spring disk stack 118 is replaced by a single leaf spring 260. The leaf spring 260 connects the two compliant pivot joints 40, 42. In certain embodiments, replacing the two spring disk stacks 118 with a single leaf spring 260 may be advantageous because the number of parts is reduced. Fig.14 and Fig.15 They are shown respectively Fig.13 1 and 2 are enlarged perspective and cross-sectional views of the compliant pivot joints 40 , 42 rotatably coupling the rear pivot link 32 to the seat cushion frame 24 and the seat base 28 . Fig.16 Shows Fig.15 16, which illustrates additional details of one of the compliant pivot joints 40, 42. In addition, Fig.17 Shows Fig.14 An exploded view of the compliant pivot joints 40, 42.

[0070] Reference Fig.14 and Fig.15 An exemplary embodiment of the leaf spring 260 is a stamped and / or formed bracket having a first leaf portion 264 spaced apart from a second leaf portion 264', and the first leaf portion 264 and the second leaf portion 264' are connected by a generally U-shaped channel 268. Fig.15 As shown in FIG. 1 , each of the first and second reed portions 264 , 264 ′ includes a hole 272 having an inner diameter that is greater than an outer diameter of the first shaft portion 74A of the shoulder bolt 58 .

[0071] exist Figures 13 to 19 In the embodiment shown in FIG. 1 , the leaf spring 260 is formed of a full hard tempered stainless steel plate (SS301) having a thickness of about 1.5 mm between the opposing upper and lower surfaces 260A, 260B, a width of about 25 mm, and an overall length of about 115 mm between the opposing ends 260C, 260D of the leaf spring 260. Another embodiment of the leaf spring 260 is formed of alloy steel AISI 5160 heat treated and tempered to HRC 55-65. It will be appreciated that the leaf spring 260 may be formed of other metals including, but not limited to, steel, spring steel, stainless steel, alloy steel, heat treated steel, and tempered steel.

[0072] exist Fig.17 The assembly of the compliant pivot joints 40, 42 connected by the leaf spring 260 is illustrated in FIG. Fig.17The compliant pivot joints 40, 42 are assembled by attaching the spline nuts 46 to the associated apertures 48 in the seat cushion frame 24 and the seat base 28, respectively. The shaft end 78 of each shoulder bolt 58 passes through a corresponding hole 272 in the leaf spring 260, through a corresponding opening 82 in the rear pivot link 32, and is secured to a corresponding spline nut 46. Optionally, grease 156 ( Fig.18 ) is applied to the interface between the cup-shaped protrusion 90 of the rear pivot link 32 and the curved shoulder surface 62 of the spline nut 46. Adding grease 156 to the interface between the cup-shaped protrusion 90 and the spline nut 46 reduces friction in the compliant pivot joints 40, 42.

[0073] Fig.18 An unconstrained profile 280 of the leaf spring 260 and a constrained profile 280 ′ of the same leaf spring 260 constrained between the bolt head 76 of the shoulder bolt 58 and the rear pivot link 32 are shown. Fig.16 2 shows an enlarged view of the leaf spring 260 constrained between the lower surface 76' of the bolt head 76 and the rear pivot link 32. When the leaf spring 260 is constrained during assembly, as by Fig.18 As shown in the constrained profile 280' in FIG. 2 , the end portion 296 of the leaf spring 260 between each of the holes 272 and the adjacent leaf spring end 260C, 260D moves toward the associated cup-shaped projection 90. As a non-limiting example, the end portion 296 of the leaf spring 260 can frictionally engage and disengage from the associated cup-shaped projection 90 based in part on the tolerance stack-up of the various components, dimensional variations, specific dimensions, the amount of fore-aft loads 144' and side loads 148' applied to the compliant pivot joints 40, 42, and the like.

[0074] In addition, when Fig.18 When the leaf spring 260 is repositioned from the unconstrained profile 280 toward the constrained profile 280', the second portion 300 of the leaf spring 260 adjacent to each of the holes 272 will be repositioned toward the associated bolt head 76, such as Fig.18 As a non-limiting example, the second portion 300 of the leaf spring 260 can be frictionally engaged and disengaged from the associated bolt head 76 based in part on tolerance stack-ups of the various components, dimensional variations, specific dimensions, the amount of fore-aft loads 144' and side loads 148' applied to the compliant pivot joints 40, 42, etc.

[0075] The leaf spring 260 has an unconstrained profile 280 that is sized and shaped so that the U-shaped channel 268 will interfere with the rear pivot link 32 during assembly, as shown in FIG. Fig.18As shown in FIG. 4 . When the shoulder bolt 58 is tightened by the spline nut 46 and the U-shaped channel 268 contacts the rear pivot link 32, the U-shaped channel 268 is pressed upward toward the constrained profile 280 ′ (arrow 308). In addition, the upward movement 308 of the U-shaped channel 268 causes the opposite ends 260C, 260D of the leaf spring 260 to move downward, as indicated by Fig.18 As shown in FIG. Fig.19 As shown in , the upward movement 308 of the U-shaped channel 268 during assembly introduces biasing forces B1 , B2 into the leaf spring 260 .

[0076] exist Fig.18 In the embodiment shown in , when the first and second reed portions 264, 264' are unconstrained and resting on a flat surface, the U-shaped channel 268 of the leaf spring 260 has a valley 316 that is offset 320 approximately 9.5 mm from the upper surface 260A of the first and second reed portions 264, 264'. It will be understood that the actual dimensions and selected materials of the leaf spring 260 will vary based on the intended application. There is also a second offset distance 320' between the contact surface 32C on the rear pivot link 32 and the lower surface 76' of the bolt head 76. The offset distance 320 between the valley 316 of the U-shaped channel 268 and the unconstrained first and second reed portions 264, 264' is greater than the second offset distance 320'. Referring to Fig.18 and Fig.19 , increasing the offset distance 320 of the leaf spring 260 as compared to the second offset distance 320′ between the contact surface 32C and the lower surface 76′ of the bolt head 76 will increase the amount of biasing force B1 applied to the bolt head 76 by the leaf spring 260. Likewise, decreasing the offset distance 320 of the leaf spring 260 as compared to the second offset distance 320′ between the contact surface 32C and the lower surface 76′ of the bolt head 76 will decrease the amount of biasing force B1 applied to the bolt head 76 by the leaf spring 260.

[0077] like Fig.19As shown in , the biasing force B1 applied to the bolt head 76 by the leaf spring 260 is offset by the biasing force B2 applied to the rear pivot link 32 by the leaf spring 260. The fore-aft load 144' and / or the side load 148' applied to the compliant pivot joints 40, 42 are offset by the biasing forces B1, B2 applied to the bolt head 76 and the rear pivot link 32 by the leaf spring 260 and the load B3 absorbed by the engagement surface between the curved shoulder surface 62 of the spline nut 46 and the cup-shaped protrusion 90 of the rear pivot link 32. The amount of the biasing force B1 applied to the bolt head 76 by the leaf spring 260 is affected by the amount of displacement of the U-shaped channel 268 during assembly by engaging with the contact surface 32C of the rear pivot link 32. More specifically, the biasing forces B1, B2 applied by the leaf spring 260 are spring loads generated by deforming the leaf spring 260 during assembly. Thus, by adjusting the relative amounts of the offset distances 320 , 320 ′, the amount of biasing force B1 applied to the bolt head 76 by the leaf spring 260 may be increased and / or decreased.

[0078] One benefit of a compliant pivot joint for a vehicle seat is that the compliant pivot joint limits perceived looseness in the compliant pivot joint in response to applied fore-aft and side loads. A second benefit is that the biasing member within the compliant pivot joint allows the compliant pivot joint to have sufficient lateral clearance within the compliant pivot joint to maintain rotational friction within a target range. A third benefit is that the compliant pivot joint has a low amount of rattle in response to applied fore-aft and side loads. Finally, the compliant pivot joint has a reduced likelihood of buzzing, squeaking and rattling noises compared to a typical bushing pivot joint.

[0079] The present invention has been described in an illustrative manner, and it should be understood that the terms that have been used are intended to have the nature of descriptive words rather than limiting words. In view of the above teachings, many modifications and variations of the present invention are possible. Therefore, it should be understood that within the scope of the appended claims, the present invention may be practiced in ways other than as specifically described.

Claims

1. A compliant pivot joint for a vehicle seat, the compliant pivot joint include: Connecting rod member; Frame members; a cup-shaped opening passing between opposing upper and lower surfaces of a cup-shaped protrusion formed on one of the link member and the frame member; a fastener having an outer surface extending between opposing upper and lower end surfaces, a curved shoulder surface extending between the upper and outer surfaces, and wherein the lower end surface of the fastener is fixedly coupled to the other of the link member and the frame member; a shoulder bolt having a shaft projecting axially from a bolt head and terminating at a shaft end, the shaft including a first shaft portion projecting from the bolt head and terminating at a first end wall adjacent to a second shaft portion, the first end wall defining a shoulder; and a biasing member having a biasing opening; wherein the shaft of the shoulder bolt extends through the offset opening and through the cup-shaped opening, wherein the shoulder bolt is fixedly coupled to the fastener; wherein the biasing member is spaced between the upper surface of the cup-shaped protrusion and the bolt head of the shoulder bolt and biases the bolt head away from the cup-shaped protrusion; and wherein the curved shoulder surface of the fastener frictionally engages the lower surface of the cup-shaped protrusion, and the shoulder of the shoulder bolt frictionally engages the upper end surface of the fastener.

2. The compliant pivot joint according to claim 1, in: The biasing member includes two or more conical washers stacked in series.

3. The compliant pivot joint of claim 1, in: The biasing member includes a plurality of tapered washers stacked in series, in parallel, and / or a combination of series and parallel.

4. The compliant pivot joint of claim 2, include: The fastener is a nut having a threaded channel; and The shoulder bolt includes a threaded shaft portion configured to meshingly engage the threaded passage in the nut.

5. The compliant pivot joint of claim 4, in: At least a portion of one or more of the curved shoulder surface and the lower surface of the cup-shaped projection is coated with grease.

6. The compliant pivot joint of claim 5, in: The first shaft portion has a first outer diameter; and The second shaft portion has a second outer diameter that is smaller than the first outer diameter.

7. A compliant pivot link assembly for a vehicle seat, the compliant pivot link assembly include: a pivot link having a first cup-shaped protrusion and a second cup-shaped protrusion, each of the first cup-shaped protrusion and the second cup-shaped protrusion having opposing upper and lower surfaces, wherein a cup-shaped opening extends between the opposing upper and lower surfaces; a first fastener and a second fastener, each of the first fastener and the second fastener having opposing top and bottom surfaces and a curved shoulder surface extending from the top surface; a first shoulder bolt and a second shoulder bolt, each of the first shoulder bolt and the second shoulder bolt having a bolt head, an upper shaft portion projecting axially from the bolt head and terminating in a shoulder, and a lower shaft portion projecting axially from the shoulder; and a first biasing member and a second biasing member, each of the first biasing member and the second biasing member having a biasing opening extending axially through the each of the first biasing member and the second biasing member; wherein each of the first shoulder bolt and the second shoulder bolt extends through the biasing opening in the respective one of the first biasing member and the second biasing member, extends through the cup-shaped opening in the respective one of the first cup-shaped protrusion and the second cup-shaped protrusion, and is fixedly coupled to the respective one of the first fastener and the second fastener, wherein the shoulder frictionally engages the top surface of the respective one of the first fastener and the second fastener; wherein each of the first biasing member and the second biasing member is spaced between the upper surface of the corresponding one of the first cup-shaped protrusion and the second cup-shaped protrusion and the bolt head of the corresponding one of the first shoulder bolt and the second shoulder bolt; and wherein the curved shoulder surface of each of the first and second fasteners frictionally engages the lower surface of the corresponding one of the first and second cup-shaped protrusions.

8. The compliant pivot linkage assembly of claim 7, in: Each of the first biasing member and the second biasing member includes two or more tapered washers stacked in series, in parallel, and / or a combination of series and parallel.

9. The compliant pivot linkage assembly of claim 8, in: The first biasing member and the second biasing member include the same number of conical washers.

10. The compliant pivot linkage assembly of claim 8, in: The first biasing member and the second biasing member include different numbers of conical washers.

11. The compliant pivot linkage assembly of claim 7, in: The first biasing member and the second biasing member are first and second reed portions, respectively, of a single leaf spring, wherein each of the biasing openings extends through a respective one of the first and second reed portions.

12. The compliant pivot linkage assembly of claim 11, in: The first reed portion and the second reed portion are separated by a U-shaped channel; and The U-shaped channel frictionally engages the pivot link.

13. The compliant pivot linkage assembly of claim 7, in: a first frame member fixedly coupled to the bottom surface of the first fastener; and A second component is fixedly coupled to the bottom surface of the second fastener, the second component being a second frame component or a link component.

14. A compliant pivot joint for a vehicle seat, the compliant pivot joint include: Connecting rod member; Frame members; a cup-shaped opening passing between opposing upper and lower surfaces of a cup-shaped protrusion formed on one of the link member and the frame member; a hole formed in the other of the link member and the frame member; a fastener having an outer surface extending between opposed upper and lower end surfaces and a threaded passage extending between the opposed upper and lower end surfaces; a biasing member having a biasing opening extending axially therethrough; as well as a shoulder bolt having a shaft projecting axially from a bolt head and terminating at a shaft end, the shaft including a first shaft portion, a second shaft portion, and a third shaft portion, the first shaft portion having a first outer wall projecting from the bolt head and terminating at a first end wall and having a curved shoulder surface extending between the first outer wall and the first end wall, the second shaft portion projecting axially from the first end wall and terminating at a second end wall, the second end wall defining a second shoulder, and the third shaft portion projecting axially from the second end wall, at least a portion of the third shaft portion including external threads configured to meshingly engage with the threaded passage of the fastener, wherein the bolt head is configured such that an outer diameter of the bolt head is greater than an inner diameter of the hole, the outer diameter of the first shaft portion is less than the inner diameter of the hole and greater than the inner diameter of the cup-shaped opening, and the outer diameters of the second and third shaft portions are less than the inner diameters of the hole, the cup-shaped opening, and the offset opening; wherein said shaft of said shoulder bolt extends through said bore, said cup-shaped opening and said offset opening, wherein said curved shoulder surface frictionally engages said lower surface of said cup-shaped projection; wherein the threaded passage of the fastener meshingly engages the external threads of the third shaft portion, wherein the lower end surface of the fastener frictionally engages the second shoulder of the shoulder bolt; and wherein the biasing member is spaced between the lower end surface of the fastener and the upper surface of the cup-shaped protrusion and biases the fastener away from the cup-shaped protrusion.

15. The compliant pivot joint of claim 14, in: The biasing member includes a plurality of tapered washers stacked in series, in parallel, and / or a combination of series and parallel.

16. The compliant pivot joint of claim 14, in: A second compliant pivot joint rotationally couples the link member to a second component.

17. The compliant pivot joint of claim 16, in: The cup-shaped protrusion is formed in the link member; The biasing member is a leaf portion of a single leaf spring; and The leaf spring includes a U-shaped channel coupling the leaf portions, the U-shaped channel frictionally engaging the link member.

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