FR3031149A1 - ROD FOR VEHICLE SEAT AND VEHICLE SEAT COMPRISING SUCH ROD - Google Patents

Abstract

Connecting rod (10) for a vehicle seat comprising an insert (20) formed in one piece substantially cylindrical and made of metallic material and a body (11) of plastic material molded onto the insert, the insert being rotatable by relation to the body.

Description

FIELD OF THE INVENTION The present invention relates to connecting rods for a vehicle seat and to vehicle seats comprising such connecting rods. BACKGROUND OF THE INVENTION BACKGROUND OF THE INVENTION Connecting rods comprising a body molded on at least one insert of extremely complex structure, said insert being rotatable relative to the body. Such rods have the disadvantage of involving the use of a relatively large number of parts (especially for the structure of the insert) and to be of expensive industrial implementation. Also known are vehicle seat rods comprising a body overmolded on at least one insert in one piece, said insert then being integral in rotation with the overmolded body. Such connecting rods have the disadvantage of no longer providing an insert that is rotatable relative to the body of the connecting rod. The object of the present invention is in particular to provide a connecting rod comprising a movable insert in rotation. SUMMARY OF THE INVENTION For this purpose, the invention mainly proposes a connecting rod for a vehicle seat comprising: at least one substantially cylindrical one-piece insert made of metallic material, and a plastic body overmolded on said at least one insert, said at least one insert being rotatable relative to the body. With these arrangements, the connecting rod for vehicle seat consists of a small number of parts and always includes an insert movable in rotation relative to the body. The manufacturing and assembly processes are thus simplified, and the costs of these processes and assembly times are reduced. In addition, the weight of such a rod is greatly reduced. In various embodiments of the invention, one or more of the following arrangements may also be used: said body is made of polyamide; said at least one insert is covered with a surface treatment; The surface treatment consists of the deposition of a zinc alloy layer, in particular a zinc-nickel layer; said at least one insert comprises a first axial face exposed outside said body and a second axial face opposite to said first axial face, and wherein said at least one insert further comprises a first cylindrical portion adjoining the second axial face and having a first diameter, and a second cylindrical portion contiguous to the first axial face and having a second diameter smaller than the first diameter; said at least one insert comprises a first axial face and a second axial face opposite to said first axial face, said first and second axial faces being apparent outside said body, and wherein said at least one insert further comprises a first cylindrical portion having a first diameter, a second cylindrical portion adjoining the first axial face and having a second diameter smaller than the first diameter, and a third cylindrical portion adjoining the second axial face and having a third diameter smaller than the first diameter ; said at least one insert comprises at least one first axial face exposed outside the body and furthermore a threaded hole opening into said first axial face; - The rod further comprises at least one reinforcement strip of composite material consisting of thermoplastic material reinforced with continuous fibers and at least partially surrounding said at least one insert, said body being overmolded on said reinforcing strip; - The connecting rod comprises at least two inserts each formed in one piece substantially cylindrical and made of metal material, and wherein the plastic body is overmolded on the at least two inserts, each of said at least two inserts being rotatable in relation to said body; the reinforcement strip is continuous, non-crossed and connects the at least two inserts; Furthermore, the invention further relates to a vehicle seat comprising at least two seat parts interconnected by at least one connecting rod as defined above. Furthermore, the subject of the invention is furthermore a method of manufacturing a connecting rod as defined above, the method comprising: placing the at least one insert in a mold, overmolding the plastic body on the at least one insert so that said at least one insert is rotatable relative to said body. In various embodiments of the manufacturing method, one or both of the following arrangements may be used: the method further comprises, prior to the overmolding step, the step of covering the at least one insert with a surface treatment; the method further comprises, preceding the overmolding step, the step of at least partially surrounding the at least one insert with a reinforcement strip of composite material made of thermoplastic material reinforced with continuous fibers. BRIEF DESCRIPTION OF THE FIGURES Other features and advantages of the invention will become apparent from the following description of one of its embodiments, given by way of illustration, with reference to the accompanying drawings, in which: FIG. schematic view of a seat that may include a connecting rod according to the invention, - Figure 2a is a perspective view of the rod according to the invention, - Figure 2b is a perspective view of the rod according to the invention of which the inserts are pierced; FIG. 3 is a view from above of the connecting rod of FIG. 2, the inserts of which are threaded; FIG. 4 is a cross-sectional view along the axis IV-IV shown in FIG. according to a first embodiment of the invention, - Figure 5 is a cross-sectional view along the axis IV-IV 25 shown in Figure 3 according to a second embodiment of the invention, - Figure 6 is a cross-sectional view along the axis IV-IV shown in Figure 3 according to a third embodiment of the invention, - Figure 7 is a cross-sectional view along the axis IV-IV shown in Figure 3 according to a fourth embodiment of the FIG. 8 is a view from above of a step of manufacturing the connecting rod according to the invention. DETAILED DESCRIPTION OF THE INVENTION In the various figures, the same references designate identical or similar elements.

FIG. 1 schematically represents a vehicle seat 1, for example a motor vehicle, comprising a backrest 2 rotatably mounted, for example around a seat 3. The rotation of the backrest 2 relative to the seat 3 is around a transverse direction Y. The vehicle seat 1 is defined in a space comprising the transverse direction Y, and a vertical plane XZ. the seat 1 further comprises a headrest 4 mounted hard backrest 2. The seat 3 is mounted on the floor P of the vehicle in known manner, such as by means of slides 5. The seat 3 is by example connected to the slides 5 by means of a raising device known per se, for adjusting the height of the seat 3. The raising device is for example composed of connecting rods 10 arranged on both sides of the seat. sitting 3.

Figures 2a, 2b and 3 show the connecting rod 10 according to the invention. The connecting rod 10 comprises a body 11 and at least one insert 20. The body 11 extends substantially in a main direction U between a head 12 and a foot 13. The head 12 comprises, for example, a first insert 20 and the foot 13 comprises, for example, a second insert 20.

Alternatively, only the head 12 comprises an insert 20. Alternatively, the body 11 of the connecting rod 10 comprises at least three inserts 20. The body 11 also has a thickness L1 extending substantially in a secondary direction V, perpendicular to the direction main U.

The body 11 of the connecting rod 10 is made of plastic. More particularly, the body 11 of the rod 10 is made of polyamide (PA). More particularly, the body 11 of the connecting rod can be made with semicrystalline aliphatic homopolyamide (PA 6.6 or PA6) or semi-aromatic polyamide, or amorphous polyphthalamide (PA 6.1).

The body 11 is obtained by injection molding plastic material onto the at least one insert 20. The body 11 is overmoulded on the at least one insert 20. The body 11 coats the major part of the at least one insert 20 (to the possible exception of some axial faces 20a, 20b left free, visible in Figures 2a to 7, which will be described later). The at least one insert is then integral in translation with the body 11.

Alternatively, the body 11 comprises recesses 15. The recesses 15 reduce the weight of the connecting rod 10. The insert 20 can be in one piece. An integrally formed insert 20 simplifies the production and assembly processes of the rod 10, thereby reducing the costs and times of these processes.

The insert 20 is adapted to be rotatable relative to the body 10 of the connecting rod 10. The insert 20 has a substantially cylindrical general shape. More particularly, the insert 20 is elongate in the secondary direction V between a first axial face 20a and a second axial face 20b. The first axial face 20a 5 and the second axial face 20b are in two planes strictly parallel to each other. The first axial face 20a and the second axial face 20b have, for example, a substantially circular section. The distance between the first axial face 20a and the second axial face 20b has a length L2. The insert 20 further comprises a peripheral surface 20c connecting the first axial face 20a to the second axial face 20b. The peripheral surface 20c is substantially cylindrical. For example, a cross section of the peripheral surface 20c is circular. The cross section of the insert 20 further has a first characteristic dimension (inscribed diameter) D1 extending in a third direction T, perpendicular to the main direction U and the secondary direction V.

Alternatively, the insert 20 comprises a first cylindrical portion 21 and a second cylindrical portion 22 (Figure 4). The cross section of the first cylindrical portion 21 of the insert 20 has the first characteristic dimension D1. The cross section of the second cylindrical portion 22 of the insert 20 has a second characteristic dimension (inscribed diameter) D2 smaller than the first characteristic dimension D1. This form of the insert 20 is adapted to reinforce the connection between the body 11 of the rod 10 and the insert 20 and to improve the rotation of the insert 20 relative to said body 11. The first cylindrical portion 21 comprises for example the second axial face 20b. The second cylindrical portion 22 comprises for example the first axial face 20a.

The first axial face 20a of the insert 20 may be visible outside the body 11 of the rod 10. The first axial face 20a and the outer surface of the rod 10 may be in two planes combined. The first axial face 20a is aligned with the outer surface of the rod 10. Alternatively, the first axial face 20a and the outer surface of the rod 10 are in two planes strictly parallel to each other. The plane comprising the first axial face 20a is then recessed relative to the plane comprising the outer surface of the connecting rod 10, so that the at least one insert 20 is pressed into the body 11, or is in advance with respect to the plane comprising the outer surface of the connecting rod 10, so that the at least one insert 20 projects from the body 11.

The second axial face 20b and the peripheral surface 20c of the insert 303 are not apparent outside the body 11 of the connecting rod 10 (FIG. 4). The second axial face 20b and the peripheral surface 20c can be entirely covered by the body 11 of the connecting rod 10. The length L2 of the insert 20 is smaller than the thickness L1 of the body 11 of the connecting rod 10.

Alternatively, the second axial face 20b of the insert 20 is exposed outside the body 11 of the rod 10. Alternatively, a portion of the peripheral surface 20c of the insert 20 is visible outside the body 11 Alternatively, the insert 20 further comprises a third cylindrical portion 23 ((Figures 5 and 6) .The peripheral surface 20c of the first, second and third cylindrical portions 21, 22 and 23 is substantially cylindrical. third cylindrical portion 23 of the insert 20 has a third characteristic dimension (inscribed diameter) D3 smaller than the first characteristic dimension D. This form of the insert 20 is adapted to reinforce the connection 15 between the body 11 of the connecting rod 10 and the insert 20 and to improve the rotation of the insert 20 relative to said body 11. The second cylindrical portion 22 comprises for example the first axial face 20a and the third cylindrical portion. Ndrique 23 comprises for example the second axial face 20b. The second characteristic dimension D2 is, for example, equal to the third characteristic dimension D3. The first axial face 20a of the insert 20 may be visible outside the body 11 of the rod 10. The second axial face 20b and the peripheral surface 20c of the insert 20 are not apparent outside the body 11 of the the rod 10 (Figure 5). The second axial face 20b and the peripheral surface 20c can be entirely coated by the body 11 of the rod 10. The length L2 of the insert 20 is smaller than the thickness L1 of the body 11 of the rod 10. Alternatively, the second axial face 20b of the insert 20 is apparent outside the body 11 of the rod 10 (Figure 6). The length L2 of the insert 20 is at least equal to the thickness L1 of the body 11 of the connecting rod 10.

Alternatively, a portion of the peripheral surface 20c of the insert 20 is exposed outside the body 11. Alternatively, the first cylindrical portion 21 of the insert 20 comprises a groove 24 (Figure 7). The groove 24 has a fourth characteristic dimension (inscribed diameter) D4 less than the first characteristic dimension D1.

The insert 20 is made of metallic material such as aluminum, steel or any other suitable metallic material. The composition of the insert 20 of metal material allows said insert 20 to be rotatable relative to the body 11. The insert 20 is further subjected, for example, to a surface treatment. Said surface treatment is adapted to facilitate the rotation of the insert 20 relative to the body 11 of the connecting rod 10. The surface treatment of the insert 20 comprises a first step of depositing on the surface of the insert 20 a first layer of zinc alloy. The first zinc alloy layer has a thickness, for example, of 7 to 10 μm (micrometer) and more particularly about 8 μm. The surface of the insert 20 comprises the first and second axial faces 20a and 20b and the peripheral surface 20c. The first layer of zinc alloy improves the rotation of the insert 20 relative to the body 11 of the rod 10. More particularly, the first layer of zinc alloy covering the surface of the insert 20 is a first layer of zinc -nickel. Alternatively, the surface treatment of the insert 20 further comprises a second step of passivating the first layer of zinc alloy. Passivation of the first layer of zinc alloy is carried out with trivalent chromium. Passivation of the first alloyed zinc layer of the insert 20 consists of the application of a protective film to the first zinc alloy layer. The protective film 20 has a thickness, for example, of 0.2 to 2 μm. The passivation of the first zinc alloy layer substantially slows the corrosion rate of the insert 20. The passivation of the insert 20 is performed after the deposition of the first zinc alloy layer on said insert 20.

Alternatively, the surface surface treatment of the insert 20 further comprises a third step of performing an organomineral finish on said insert 20. The organo-mineral finish of the insert 20 is made, for example, by dipping or with the pistol. The organo-mineral finish gives rise to a protective layer on the insert 20. More particularly, the organo-mineral finish makes a protective layer appear on the protective film of the insert 20. The protective layer has a thickness, for example from 1 to 21..tm. The organomineral finish of the protective film of the insert 20 makes it possible to improve the rotation of the insert 20 relative to the body 11 of the connecting rod 10.

The organo-mineral finish of the insert 20 is performed after the passivation 3031149 8 of the insert 20. Alternatively, the insert 20 comprises a hole 29 extending in the secondary direction V (Figure 2b). Thus, a shaft (not shown) is adapted to fit into said hole 29, securing the insert 20 to said shaft. The hole 29 opens, for example, into the first axial face 20a. Alternatively, the hole 29 also opens into the second axial face 20b. Alternatively, the insert 20 comprises an internally threaded hole 30 extending in the secondary direction V. Thus, an externally threaded member 31, such as for example a screw, is adapted to fit into said threaded hole 30, solidarising the insert 20 to said threaded member 31. The threaded hole 30 opens, for example, in the first axial face 20a. Alternatively, the threaded hole 30 opens further into the second axial face 20b.

Alternatively, the connecting rod 10 further comprises a reinforcing strip 40. The reinforcing strip 40 has, for example, a band shape and can be continuous. The reinforcing strip 40 at least partially surrounds said at least one insert 20. The reinforcing strip 40 is in direct contact with the at least one insert 20.

In the embodiment shown in FIG. 8, the reinforcing strip 40 is non-crossed and connects a first insert 20 to at least a second insert 20. Alternatively, the reinforcing strip 40 is crossed and connects the first insert 20 to the at least one second insert 20. The reinforcing strip then has a general shape of 8. The reinforcing strip 40 may be arranged partly in the groove 24, around the at least one insert 20. This configuration facilitates the assembly of the reinforcing strip 40 on the insert 20. The body 11 is overmolded on the at least one insert 20 and on the reinforcing strip 40. The reinforcing strip 40 is coated by the body 11 of the connecting rod 10 (FIG. 6). The reinforcement strip 40 may especially be made of a composite material made of continuous fiber-reinforced plastics material ("CFRT"). The reinforcing strip 40 makes it possible to reinforce the resistance of the connecting rod 10 to traction while minimizing the increase in the overall weight of the connecting rod 10.

Alternatively, granules (not shown) of composite material 30311499 made of continuous fiber reinforced plastic ("CFRT") are disposed around the at least one insert 20. More particularly, the granules are arranged at close distance of the at least one insert 20. The body 11 is overmolded on the at least one insert 20 and coats the granules. There is no direct contact between the granules and the at least one insert 20. The granules make it possible to reinforce the resistance of the connecting rod 10 to traction while minimizing the increase in the general weight of the connecting rod 10. The rod 10 has just been described is adapted to connect at least two seat parts 1. More particularly, the rod 10 may for example find an application in the internal mechanisms of headrest 4, in 10 foldable tablets mounted on the back of the seat backrests 2, in the seat seat riser mechanisms 3, in the slide locks 5, in the holding connections of the internal frames of the seat 1, etc.

Claims (13)

REVENDICATIONS1. Connecting rod for a vehicle seat comprising: - at least one insert (20) formed in one piece substantially cylindrical and made of metallic material, - a body (11) of plastic material molded onto said at least one insert, said at least one insert being rotatable relative to said body (11). 2. Connecting rod according to claim 1, wherein said body (11) is made of polyamide. 3. Rod according to claim 1 or claim 2, wherein said at least one insert (20) is covered with a surface treatment. 4. Rod according to claim 3, wherein the surface treatment consists of the deposition of a layer of zinc alloy, in particular a zinc-nickel layer. (List of other alternatives pending) 5. Rod according to any one of the preceding claims, wherein said at least one insert (20) comprises a first axial face (20a) apparent outside said body (11) and a second axial face (20b) opposite to said first axial face, and wherein said at least one insert further comprises a first cylindrical portion (21) adjoining the second axial face (20b) and having a first diameter (D1), and a second cylindrical portion (22) adjoining at the first axial face (20a) and having a second diameter (D2) smaller than the first diameter (D1). 6. Rod according to any one of claims 1 to 4, wherein said at least one insert (20) comprises a first axial face (20a) and a second axial face (20b) opposite to said first axial face, said first and second axial faces (20a, 20b) being apparent outside said body (11), and wherein said at least one insert further comprises a first cylindrical portion (21) having a first diameter (D1), a second cylindrical portion Adjacent to the first axial face (20a) and having a second diameter (D2) smaller than the first diameter (D1), and a third cylindrical portion (23) abutting the second axial face (20b) and having a second third diameter (D3) smaller than the first diameter (D1). 5 7. Rod according to any one of the preceding claims, wherein said at least one insert (20) comprises at least one first axial face (20a) apparent outside the body and further a threaded hole (30) opening into said first axial face. 10 8. Connecting rod according to any one of the preceding claims, further comprising at least one reinforcing strip (40) of composite material consisting of thermoplastic material reinforced with continuous fibers and at least partially surrounding said at least one insert (20), 15 said body (11) being overmoulded on said reinforcing strip. 9. Connecting rod according to any one of the preceding claims, comprising at least two inserts (20) each formed in one piece substantially cylindrical and made of metallic material, and wherein the body (11) of plastic material is overmolded on the at least two inserts (20), each of said at least two inserts being rotatable relative to said body (11). Vehicle seat comprising at least two seat parts interconnected by at least one connecting rod (10) according to any one of the preceding claims. 11. A method of manufacturing a rod (10) according to any one of claims 1 to 9, the method comprising: - arranging the at least one insert (20) in a mold, - overmoulding the body (11) in plastic material on the at least one insert so that said at least one insert is rotatable relative to said body. The method of manufacturing a connecting rod (10) according to claim 11, further comprising, prior to the overmoulding step, the step of coating the at least one insert (20) with a surface treatment . 3031149 12 13. A method of manufacturing a rod (10) according to claim 11 or claim 12, further comprising, preceding the overmolding step, the step of at least partially surrounding the at least one insert (20). a reinforcing strip (40) of composite material made of thermoplastic material reinforced with continuous fibers.