Stability Rollers For A Long Rail Assembly

A long rail assembly for repositioning a vehicle seat in a vehicle includes a fixed long rail and a rail drive assembly configured to be repositionable along the fixed long rail. The rail drive assembly includes an upper channel and a flexible stability roller assembly. The flexible stability roller assembly has first and second stability rollers rotationally coupled to respective first and second wing portions of a flexible wing bracket. The flexible wing bracket has a generally W-shaped cross-section in profile with the first and second wing portions extending at a first angle from adjacent first and second side portions, respectively, and the first and second side portions extending at a second angle from a center portion. The center portion of the flexible wing bracket is fixedly coupled to the upper channel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a rail drive assembly that supports a vehicle seat and is configured to travel along a fixed long rail when the vehicle seat is repositioned to another location along the fixed long rail. More particularly, the invention relates to a long rail drive assembly having a flexible stability roller assembly to absorb both vertical and lateral channel variation.

2. Description of Related Art

Various slide mechanisms having stability rolling elements are known for repositioning a vehicle seat along a long rail in a vehicle. One known seat sliding device is disclosed in W.O. Publication 2020/077209 wherein a vehicle seat is coupled to a rail drive assembly that is slidable within a fixed long rail. The rail drive assembly includes wheels configured to travel along an interior track of the fixed long rail. In addition, stability rolling elements are mounted at an angle to side walls of the rail drive assembly. Front and rear stability rolling elements on each side of the rail drive assembly are operationally coupled by a torsion spring extending in a longitudinal direction.

However, this known seat sliding device lacks spring-loaded stability rollers that are spring-loaded in both lateral and vertical directions to absorb channel variations. In addition, the stability rolling elements of this known seat sliding device includes a plurality of components which can be difficult to assemble. Finally, this exemplary known seat sliding device lacks spring-loaded stability rolling elements that act as a compression spring to resist lateral load applied to the vehicle seat.

It is desirable, therefore, for a rail drive assembly to have a stability roller assembly that is easy to assemble. Further, it is desirable to reduce the number of components in the stability roller assembly. In addition, it is desirable for the stability roller assembly to resist fore-aft load applied to the vehicle seat. It is also desirable that the stability roller assembly can act like a compression spring to resist lateral load applied to the vehicle seat. Finally, it is desirable for the rail drive assembly to have a stability roller assembly that absorbs both vertical and lateral channel and positional variation.

SUMMARY OF THE INVENTION

The present invention relates to a long rail assembly for repositioning a vehicle seat in a vehicle. The long rail assembly includes a fixed long rail and a rail drive assembly configured to be repositionable along the fixed long rail. The rail drive assembly includes an upper channel and a flexible stability roller assembly. The flexible stability roller assembly has first and second stability rollers rotationally coupled to respective first and second wing portions of a flexible wing bracket. The flexible wing bracket has a generally W-shaped cross-section in profile with the first and second wing portions extending at a first angle from adjacent first and second side portions, respectively, and the first and second side portions extending at a second angle from a center portion. The center portion of the flexible wing bracket is fixedly coupled to the upper channel.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIGS.1-6illustrate a long rail assembly10having a rail drive assembly12configured to transpose the rail drive assembly12along a fixed long rail14for vehicle seat adjustment according to embodiments described herein. Directional references employed or shown in the description, figures or claims, such as top, bottom, upper, lower, upward, downward, lengthwise, widthwise, left, right, and the like, are relative terms employed for ease of description and are not intended to limit the scope of the invention in any respect. Referring to the Figures, like numerals indicate like or corresponding parts throughout the several views.

FIG.1illustrates a long rail assembly10having a rail drive assembly12for adjusting a position of a vehicle seat18along a fixed long rail14according to one embodiment of the present invention.FIG.2shows a vehicle interior16having a plurality of vehicle seats18connected to rail drive assemblies12attached to a vehicle floor20. A cross-sectional view of the long rail assembly10ofFIG.1taken along section line A-A is shown inFIG.3.

Referring toFIG.2, each vehicle seat18is supported by at least one leg28on opposing sides18A,18B of the vehicle seat18, and optionally front and rear legs30,28on the opposing sides18A,18B of the vehicle seat18. Each rail drive assembly12travels along one of the fixed long rails14attached to the vehicle floor20. Each vehicle seat18travels along a pair of fixed long rails14,14′ when the vehicle seat18is repositioned between a first seat location40and a second seat location42, shown as vehicle seat18′ attached to rail drive assembly12′. The fixed long rails14can extend for any length suitable for an intended application. Likewise, any suitable number of fixed long rails14can be positioned on the vehicle floor20as desired for an intended application. Thus, the long rail assembly10allows for improved vehicle seat18position adjustment since the vehicle seat18coupled to at least one rail drive assembly12is repositionable to any seat position40,42along the at least one fixed long rail14. In certain embodiments, the rail drive assembly12is a manual rail drive assembly that is manually repositioned along the fixed long rail14. In other embodiments, the rail drive assembly12is a power rail drive assembly configured to be automatically repositioned along the fixed long rail14.

Returning toFIGS.1and3, the fixed long rail14has a generally U-shaped cross-section46in profile extending in a longitudinal direction, a bottom wall50, opposing first and second side walls60,64, an interior cavity68, and a top wall70having an elongated opening72extending in a longitudinal direction. Extending between each one of the first and second side walls60,64and terminating at the adjacent top wall70is an upper side wall74,78. The first and second upper side walls74,78extend at an angle from the adjacent side wall60,64. The fixed long rail14is a stamped, formed, molded, and/or rolled section of metal, plastic, or combinations of metal and plastic materials and has a length selected based on a specific application. It should be appreciated that the size and shape of the fixed long rail14may vary without altering the scope of the invention. The dimensions of the fixed long rail14, including the cross-sectional profile46, are selected, in part, based on generally known engineering calculations, finite element analysis (FEA), and physical testing.

Also shown inFIGS.1and3, the rail drive assembly12includes an elongated upper channel94having a generally W-shape cross-section96in profile, opposing first and second side walls98,100and a top wall102extending between the opposing first and second side walls98,100. An axle106extends laterally through a hollow tube108extending between the opposing side walls98,100. A wheel110is fixedly coupled to each end106A of the axle106. The rail drive assembly12shown in the embodiment ofFIG.1includes a pair of wheels110positioned adjacent to opposing ends94A,94B of the upper channel94. While not shown, the wheels110can be replaced by rollers and/or glides. Any number and/or combination of wheels110, rollers, and/or glides may be used as suitable for an intended application. Further, each wheel110or roller can be rotationally attached to the upper channel94using a shaft (not shown) fixedly coupled to one of the side walls98,100of the upper channel94.

In the embodiment shown inFIG.1, each pair of wheels110is attached to carrier112having a generally inverted U-shape cross-section in profile. The carrier112includes an upper wall112A extending between opposing first and second side walls112B,112C. The axle106passes through a hole112D in each of the opposing first and second side walls112B,112C. The carrier112is fixedly coupled to the upper channel94.

As shown inFIG.1, the rail drive assembly12includes spaced apart first and second flexible stability roller assemblies116,116′. Each of the first and second flexible stability roller assemblies116,116′ is positioned near a respective end94A,94B of the upper channel94.

Referring toFIG.3, the flexible stability roller assemblies116,116′ are fixedly coupled to a lower side102A of the top wall102of the upper channel94. Each flexible stability roller assembly116,116′ includes first and second stability rollers118A,118B rotationally coupled to a flexible wing bracket120. In the embodiment shown inFIG.3, a center portion120A of the flexible wing bracket120is welded to the upper channel94in two spaced apart locations124A,124B. In certain embodiments, the flexible wing bracket120is welded to the upper channel94in one location124A,124B. It will be understood that the flexible wing bracket120can be fixedly coupled to the upper channel94through other known methods including but not limited to a mechanical fastener, crimping, welding, and press fit.

The flexible wing bracket120is shown removed from the rail drive assembly12inFIG.4. The flexible wing bracket120is a flexible bracket formed out of a metal material such as high strength low alloy (HSLA) steel. One exemplary suitable HSLA steel is Society of Automotive Engineers (SAE) grade980. It will be understood that other grades and types of steel can be used in alternate embodiments without altering the scope of the invention. Referring toFIG.4, the flexible wing bracket120has a general W-shape with opposing first and second side portions120B,120C extending from the center portion120A. Each of opposing first and second wing portions120D,120E extend from the adjacent first and second side portions120B,120C. In the embodiment shown inFIG.4, each of the first and second side portions120B,120C are connected to the center portion120A by a first curved portion120F. The first and second wing portions120D,120C are connected to the adjacent side portions120B,120C by a second curved portion120G. The flexible wing bracket120has an unconstrained profile128(i.e., a “free” profile) inFIG.4. The first and second side portions120B,120C project from the center portion120A an angle132of about ninety degrees. However, the specific size, shape, and orientation of the center portion120A and the first and second side portions120B,120C are selected to fit within the upper channel94. As such, the size, shape, and orientation of the center portion120A and the first and second side portions120B,120C will vary to fit alternate embodiments of the upper channel94.

Also shown inFIG.4, the first and second wing portions120D,120E project away from the adjacent first and second side portions120B,120C at an angle136of about forty degrees. It will be understood that the angle136between the first and second wing portions120D,120E and the adjacent first and second side portions120B,120C can vary in alternate embodiments. For example, in certain embodiments the unconstrained angle136between the first and second wing portions120D,120E and the adjacent first and second side portions120B,120C, is selected to be between thirty degrees and fifty degrees, as a non-limiting example. It will be understood that the unconstrained angle136is selected based in part on the specific profile and dimensions of the fixed long rail14. In the embodiment shown inFIG.4, the flexible wing bracket120has a longitudinal length between opposing first and second end surfaces140A,140B of about 23 mm. In addition, the exemplary flexible wing bracket120has a thickness of about 1 mm as measured between opposing first and second surfaces142A,142B of the center portion120A. It will be understood that the longitudinal length of the flexible wing bracket120between the first and second end surfaces140A,140B can vary without altering the scope of the invention. Likewise, the thickness of the flexible wing bracket120between opposing first and second surfaces142A,142B can vary without altering the scope of the invention. The flexible wing bracket120is alternatively formed out of sheet stock that has been stamped, molded, formed, and/or bent, as non-limiting examples, into the desired shape.

Each of the first and second wing portions120D,120E includes an aperture148positioned near a distal end150of the first and second wing portions120D,120E and extending between the opposing first and second surfaces142A,142B, as shown inFIG.4. The aperture148is sized and shaped to matingly engage with a shaft152extending from the stability roller118A,118B. The stability rollers118A,118B are optionally rotationally coupled to the associated shaft152with the associated shaft152being fixedly coupled to the flexible wing bracket120. Alternatively, the shaft152is rotationally coupled to the flexible wing bracket120with the stability roller118A,118B being fixedly coupled to the shaft152. In addition, a washer158is assembled between the flexible wing bracket120and the stability roller118A,118B. In certain embodiments, the washer158is fixedly coupled to the shaft152, fixedly coupled to the stability roller118A,118B, or is a separate component assembled onto the shaft152.

The flexible stability roller assembly116,116′ is shown assembled with the upper channel94inFIG.5. The stability rollers118A,118B are shown assembled with the flexible wing bracket120. The flexible wing bracket120is sized and shaped such that distal ends162of the stability rollers118A,118B have a designed interference with the fixed long rail14. More specifically, the distal ends162of the stability rollers118A,118B extend beyond at least the inner surface74A,78A of the upper side walls74,78when the flexible wing bracket120is unconstrained.

FIG.6shows the flexible stability roller assembly116,116′ assembled with the fixed long rail14. A comparison of the unconstrained profile128and the constrained profile128′ of the flexible wing bracket120is shown inFIG.6. Since the unconstrained profile128of the flexible wing bracket120has a designed interference with the fixed long rail14, each of the distal ends162of the stability rollers118A,118B are pressed inward and downward, as represented by arrow166, during assembly with the fixed long rail14. In addition, each of the first and second side portions120B,120C of the flexible wing bracket120are deflected inward, as illustrated by arrow168. The flexing of the flexible wing bracket120moves the distal end162of the unconstrained profile128to abut the inner surface74A,78A of the upper side walls74,78, as illustrated by distal end162′ of the constrained profile128′. Since the flexible wing bracket120is flexible and essentially acts as a spring, the flexible wing bracket120can accommodate for variation in the dimensions of the fixed long rail14as well as accommodating for variation within the rail drive assembly12. The elastic deformation of the flexible wing bracket120absorbs channel variation in both up-down and cross-car directions. The elastic deformation during assembly can provide reaction force to the stability rollers118A,118B. Since the stability rollers118A,118B contact the fixed long rail14at an angle, the reaction force from the flexible wing bracket120can provide resistance to both up-down and cross-car variation from the rail drive assembly12. In addition, the elastic deformation of the flexible wing bracket120during assembly with the fixed long rail14acts as a compression spring to resist lateral load applied to the vehicle seat18. Further, the flexible wing bracket120assists with centering the rail drive assembly12within the fixed long rail14since the flexible wing bracket120maintains a spring bias holding the stability rollers118A,118B against the upper side walls74,78of the fixed long rail14.

In contrast, an exemplary known long rail assembly10P having spring-loaded stability roller elements181,182is shown inFIGS.7and8. Elements that are the same or similar to those used above in the embodiment shown inFIGS.1-6have the same reference numbers for simplicity. Referring toFIG.7, the known long rail assembly10P includes a known rail drive assembly12P configured to travel along a fixed long rail14P. The known rail drive assembly12P includes an upper channel94having opposing side walls98,100extending from a top wall102forming an inverted U-shape and extending between opposing ends94A,94B of the upper channel94. Wheels110are rotationally coupled to the upper channel94near each end94A,94B of the upper channel94. As shown inFIG.8, the fixed long rail14P is generally U-shaped with opposing side walls60,64extending between a bottom wall50and a top wall70of the fixed long rail14P. Extending between each side wall60,64and the adjacent top wall70is a curved portion198having a large corner radius196.

Referring toFIG.7, the known stability rolling elements181,182are rotationally coupled to each side wall98,100of the upper channel94P.FIG.8is a cross-sectional end view taken along section B-B ofFIG.7showing the stability rolling elements181,182being mounted at an angle183of about thirty degrees to the side walls98,100of the upper channel94P. Each stability rolling element181,182includes a roller184, an upper arm186,187, a lower arm188,189, and a support stud192. Each roller184is rotationally coupled to the associated upper arm186,187. Each upper arm186,187is rotationally coupled to the associated support stud192. Each support stud192is fixedly coupled to the adjacent side wall98,100at a mounting angle183, such as about 30 degrees as shown inFIG.8. In addition, the upper arm187is fixedly coupled to the lower arm189so they are linked together to move as one arm.

Referring toFIG.7, a first end208A of a torsion spring208is connected to the lower arm188of the known first stability rolling element181. A second end208B of the torsion spring208is connected to the lower arm189of the known second stability rolling element182. The torsion spring208biases the rollers184of the stability rolling elements181,182towards the adjacent fixed long rail14P curved portions198. In addition, the torsion spring208induces a longitudinal spring bias into the stability rolling elements181,182, as illustrated by arrow210shown inFIG.7. Further, the known stability rolling elements181,182can rotate with respect to the associated pivot shaft192, as illustrated by arrows212. The roller184absorbs variations in both a lateral and a vertical directions of the fixed long rail14since the roller184is angled at about 30 degrees from the side walls100,98of the upper channel94.

However, the stability rolling elements181,182of the known long rail assembly12P shown inFIGS.7and8require a plurality of parts, including the upper arm186,187, the lower arm188,189, the support stud192, and the torsion spring208. In the embodiment shown inFIGS.1-6, these components have been replaced by a single flexible wing bracket120. The reduction in the number of components directly reduces the cost and complexity of the long rail assembly12in comparison to the known long rail assembly12P.

In addition, assembly of the flexible wing bracket120with the fixed long rail14induces a lateral spring bias load into the flexible wing bracket120, as illustrated by arrow220shown inFIG.6. The torsion spring208of the known long rail assembly12P induces a longitudinal spring bias210into the stability rolling elements181,182. The known long rail assembly12P relies on the upper arms186,187being oriented at about a thirty degree angle with respect to the adjacent side wall98,100of the upper channel94in combination with the curved portion198of the side walls60,64of the fixed long rail14P to laterally bias the stability rolling elements181,182towards the side walls60,64of the fixed long rail14P. The flexible wing bracket120of the embodiment shown inFIGS.1-6actively spring biases the stability rollers118A,118B towards the adjacent upper side wall74,78of the fixed long rail14. As such, the flexible wing bracket120actively laterally stabilizes the upper channel94within the fixed long rail14.

One benefit of a rail drive assembly12for a long rail assembly10having a flexible stability roller assembly116,116′ is the flexible stability roller assembly116,116′ is easy to assemble since there are few components. A second benefit of the flexible stability roller assembly116,116′ is the cost is reduced in comparison to other known spring-loaded stability rollers since the number of components has been reduced. A third benefit is the flexible stability roller assembly116,116′ can act like a compression spring to resist lateral load applied to the vehicle seat18. A fourth benefit is the flexible stability roller assembly116,116′ can absorb both vertical and lateral channel and positional variation.