The present invention relates to runners for motor vehicle seats, and to motor vehicle seats including such runners.
More particularly, the invention relates to a runner for a vehicle seat, the runner being of the type comprising a male rail and a female rail which define between them at least a first compartment in which rolling bearing elements are disposed to enable said male and female rails to move relative to each other along a longitudinal axis. The runners serve to connect the vehicle seat to a vehicle floor.
In known runners of this type, the rolling bearing elements, which can, by way of example, be constituted by balls, are generally disposed in rows of rolling bearing elements (generally four such rows), each row of rolling bearing elements being interposed between a longitudinal portion of the male rail and a longitudinal portion of the female rail, which portions form a compartment. Therefore, when high stresses are applied to the runners by the vehicle seat, in particular in the event of a violent impact against the front or against the rear of the vehicle, the rows of rolling bearings interposed between the male rail and the female rail are alone in acting to provide the force preventing the runner from being torn open or from being crushed. Therefore, in the event that high stresses are exerted, the substantially point contact between the rolling bearing elements and the male and female rails can cause considerable deformation of said male and female rails. One effective solution could consist in increasing the thickness of the male and female rails. However, that solution would considerably increase the total weight of the runner while also increasing the cost of manufacturing it.
A particular object of the present invention is to mitigate the above-mentioned drawbacks.
To this end, according to the invention, a runner of the type in question further comprises at least one shoe received in the first compartment and mounted to slide relative to one of the rails, namely the male rail or the female rail, and said shoe comprises at least a first rigid portion having a shape substantially complementary to the shape of the first compartment in order to offer contact zones for contact with the male rail and with the female rail when the runner is subjected to deformation in a first direction.
By means of these provisions, when high stress, e.g. in traction or in compression, is applied to the runner, the rigid shoe enables the male rail to react against the female rail, thereby preventing the rolling bearing elements from participating in the retaining force for retaining the male rail relative to the female rail. The presence of the shoe thus removes any risk of the male rail and/or of the female rail being deformed irremediably, while the rolling bearing elements nevertheless make it possible for the male and female rails to move relative to each other.
In preferred embodiments of the invention, it is optionally possible also to use one or more of the following provisions:
In addition, the invention also provides a vehicle seat including a seat proper serving to be connected to a vehicle floor via at least one runner as defined above.
Other characteristics and advantages of the invention appear from the following description of one of the embodiments thereof, given by way of non-limiting example, and with reference to the accompanying drawings.
In the drawings:
In the various figures, like references designate elements that are identical or similar.
The connection between the floor 3 of the vehicle and the seat proper 2 is achieved via two parallel runners 5 (only one of which is visible in
For this purpose, as can be seen in
In the embodiment shown in
The male rail 7 is substantially upside-down channel-section, comprising a top horizontal web 71 from which two side walls 7a extend downwards, each of which is formed by a respective vertical side flange 72 extended by a folded-over lip 73 extending towards the outside of the channel section. Each lip 73 of the male rail 7 is provided with an end portion 73a which extends substantially vertically and parallel to the side flanges 72. Each of the two end portions 73a is provided with an edge 73b which, at least over a longitudinal portion, is provided with a projecting portion 74 formed integrally with the lip 73 with which it is associated.
As can be seen in FIGS. 2 to 6, when the male rail 7 is mounted inside the female rail 6, the flaps 73 and the projecting portions 74 of the male rail 7 are received between the side flanges 62 and the lips 63 of the female rail 6, while the flaps 63 of the female rail 6 are received between the side flanges 72 and the lips 73 of the male rail 7.
Thus, each lip 73 of the male rail 7 firstly defines a first compartment 8 with that side flange 62 of the female rail 6 which is associated with it, and secondly defines a second compartment 9 with that lip 63 of the female rail 6 which is associated with it.
In order to allow the male rail 7 to move longitudinally in the female rail 6, rolling bearing elements, formed by rows of balls in the example considered herein, are interposed between the male rail 7 and the female rail 6. The rows of same-diameter balls (see
As can be seen in
In order to limit the longitudinal stroke of the male rail 7 relative to the female rail 6, each projecting portion 74 is designed to co-operate with abutment elements 64 disposed on the female rail 6, when the runner 5 is assembled, i.e. when the male rail 7 is mounted to slide in the female rail 6.
More exactly, each of the side flanges 62 of the female rail 7 is provided with two abutment elements 64 which are designed to co-operate with the ends 74a of the projecting portions in order to limit the extent to which male rail 7 can move inside the female rail 6 to a predetermined stroke. Said abutment elements 64 can, in particular, be formed, after mounting the male rail 7 in the female rail 6, by stamping the vertical flanges 62 of the female rail 6 so that said abutment elements 64 are formed by stamped-out elements that project into the second compartments 9.
In addition, the side flanges 62 of the female rail 6 can also be provided with stamped-out portions 65 which project into the first compartments 8 that are defined by the lips 73 of the male rail 7 and by said side flanges 62 of the female rail 6. Said stamped-out portions 65, of which there are two in each side flange 62 serve to retain the rows of balls inside the first compartments 8. Similarly, at its bottom end, each lip 73 of the male rail 7 can also be provided with stamped-out portions 75 that project into the first compartments 8 so as also to define a raceway for the rows of balls situated in the first compartments 8.
As can be seen in
As can be seen in more detail in
In addition, each shoe 10 can also include a second rigid portion 12 which is interposed directly between the same lip 73 of the male rail 7 and the corresponding lip 63 of the female rail 6. The second rigid portion 12 of each shoe 10 also has a shape that is substantially complementary to the shape of the second compartment 9 that is associated with it, as can be seen in
The first and second rigid portions 11, 12 have respective outside faces 11a, 12a that are in contact with the side flange 62 and with the lip 63 of the female rail, and respective inside surfaces 11b, 12b that are directly in contact with the corresponding lip 73 of the male rail 7.
The inside faces 11b, 12b of the first and second rigid portions 11, 12 that surround each lip 73 of the male rail 7 have slide surfaces for enabling each lip 73 of the male rail 9 to slide relative to each shoe 10. The outside faces 11a, 12a of the first and second portions 11, 12 of each shoe 10 can be mounted to be stationary relative to the corresponding side wall 6a of the female rail 6. By way of example, the outside faces 11a, 12a of each shoe 10 can have surfaces having a coefficient of friction that is relatively high in order to adhere to that side flange 6a of the runner 6 which is associated with the shoe, and/or in order to be mounted in tight-fitting manner in the first and second compartments 8, 9 defined by the male rail 7 and by the female rail 6.
As can be seen in
For example, the rigid shoes 10 can be made of steel, of plastic, or of an aluminum alloy.
When each shoe 10 is made of steel, the inside faces 11b, 12b of the first and second portions 11, 12 can, for example, be covered with a material such as polytetra-fluoroethylene so as to enable each lip 73 of the male rail 7 to slide relative to the shoe 10 that is associated with it.
When the vehicle seat fastened to the runner and more particularly to the male rail 7 is subjected, for example, to a front impact, the front end of the male rail 7 tends to move closer to the female rail 6, thereby generating compression forces, while the rear end of the male rail 7 tends to move away from the female rail 6, thereby generating traction forces between the two rails.
In which case, the two shoes 10 situated at the front of the runner makes it possible, via their first rigid portions 11, to offer relatively wide contact zones both for the lip 73 and for the side wall 62 of the female rail 6. The first rigid portion 11 of each shoe thus makes it possible for the male rail to react against the female rail during compression stress, without going via the balls which then serve merely to enable the male and female rails to move relative to each other. Conversely, the two shoes 10 situated at the rear of the runner 5 make it possible, via their second portions 12, to offer relatively wide contact zones for the lip 73 of the male rail 7 and for the lip 63 of the female rail 6. The second rigid portion 12 of each shoe 10 thus makes it possible for the male rail to react against the lip 63 of the female rail during traction stress, without going via the balls disposed in the corresponding second compartment 9. Thus, each shoe 10 forms a rigid link between the male rail 7 and the female rail 6 in order to prevent the balls received in the compartments 8 and 9 from participating to too large an extent in the retaining force between the two rails. Thus, most of the retaining forces for retaining the runner against traction or compression are guaranteed by the shoes 10 forming a rigid link between the male rail 7 and the female rail 6 while nevertheless also making it possible for the lips 73 of the male rail 7 to slide relative to the female rail 6.
In the example shown in
In a variant embodiment, each shoe 10 can be mounted to slide relative to the male rail 7 and to the female rail 6, the shoes 10 then coming into abutting contact with the projecting portion 74 and with the corresponding abutment element 64 of the female rail 6 when the male rail 7 reaches the end of its stroke. Similarly, it is also possible to make provision for each shoe 10 also to be mounted to be constrained to move with the male rail 7 while also having outside faces 11a, 12b offering a slide surface for the corresponding side flange 62 and for the corresponding lip 63 of the female rail 6.
Number | Date | Country | Kind |
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0314925 | Dec 2003 | FR | national |