FR2928880A1 - Seat understructure for motor vehicle, has crossbeam extending between slides along transversal direction, motor carried by crossbeam, and transmission chains rotationally driving screw, where crossbeam is directly fixed to case - Google Patents

Abstract

The understructure (5) has slides (6) comprising a mobile profile (7) and a fixed profile (8) slidingly mounted with respect to each other along a longitudinal direction (X). An adjusting mechanism has a screw rotatively mounted on a case. A crossbeam (70) extends between the slides along a transversal direction (Y) that is perpendicular to the longitudinal direction. A motor (60) is carried by the crossbeam, and transmission chains rotationally drive the screw. The crossbeam is directly fixed to the case.

Description

Vehicle seat base and vehicle seat comprising such a base

The invention relates to a vehicle seat base 5 and to a vehicle seat comprising such a base. In particular, the invention relates to a vehicle seat underbody, comprising: - two rails each comprising first and second sections mounted sliding relative to each other in a longitudinal direction, and a control mechanism comprising: - a housing retained on the first profile, - first and second members formed one by a screw which extends along an axis parallel to the longitudinal direction, and the other by a nut which is engaged on the screw, said first member (which is either the screw or the nut) being rotatably mounted about the axis on the housing, and said second member (which is either the nut 20 if the screw is the first member, or the screw if the nut is the first member) being secured to the second section, - a cross member extending between the rails in a transverse direction perpendicular to the longitudinal direction, - a motor carried by the cross member and two chains of transmission adapted to rotate the first member of each adjustment mechanism. In a known basement of this type, the cross member 30 is fixed directly to the first section, which makes the manufacture of the base complex. The invention aims to simplify the manufacture of the base. For this purpose, the invention proposes a base of the aforementioned type in which the cross member is fixed directly to the housing of each adjustment mechanism.

The crossbar mounted directly on the housings of the adjustment mechanisms makes it possible, on the one hand, to reduce the manufacturing tolerances of the components of the underbody to ensure their assembly and, on the other hand, to reduce the number of assembly steps. The manufacture of the underbody is thus simplified. Such arrangements also offer the possibility of making a more direct connection between the underbody components which carry, on the one hand, the motor and the transmission chain and, on the other hand, the first rotary members so as to limit the transmission to the mobile section and therefore to the seat of the vibrations generating noise. In addition, a satisfactory relative positioning of the cross member and housings and coaxiality in the transmission chain can be ensured, independently including the positioning of the profiles resulting from the assembly of the seat and its mounting in the vehicle.

According to the embodiments, the first member of the adjusting mechanisms is formed by the screw, which is then rotatably mounted about the axis on the housing, and the second member is formed by the nut, which is then fixed. Or the first member is formed by the nut, which is then rotatably mounted about the axis on the housing, and the second member is formed by the screw, which is then fixed. It is envisaged that the underbody may comprise two fixing torques each composed of a fixing part formed on an upper half of one of the housings and of a fixing part formed at a free end of the cross-member, the fixing parts the housing and the crossbar of each fastening torque being fixed directly to one another.

To simplify the relative positioning and the mounting of the underbody, at least one of the fixing torques may comprise at least one fastening element

3 and at least one housing adapted to receive the fixing element, said fixing element and said housing being formed one on the fixing part of the housing and the other on the fixing portion of the crosspiece.

In one embodiment, the fastener and the housing extend in the transverse direction. It is thus possible to proceed to fixing the cross member on the housing by moving the cross member and the housing relative to each other in the transverse direction. The housing may, for example, be formed on the fastening portion of the housing and the fastener may be formed on the fastening portion of the cross member. The fixing portion of the housing may then comprise a head which extends in a vertical direction perpendicular to the longitudinal and transverse directions from an upper wall of said housing, the housing being formed in the head, the fixing element being a tab fitted in housing.

In a possibly complementary variant, the housing may comprise a transverse wall perpendicular to the longitudinal direction and which has an internal lateral edge near the fastening portion of the cross member, the housing being a recess formed on said transverse wall of the housing and which extends from said inner side edge, the fastener being a tab engaged in the recess. In another possibly complementary variant, the housing may comprise a side wall perpendicular to the transverse direction, the housing being a bore which extends into the housing and which has an opening on said side wall, the fixing element being a pin fitted into the bore. In another embodiment, the fastener and the housing extend in a vertical direction perpendicular to the longitudinal and transverse directions. Fixing the cross member on the housing is obtained by moving the cross member and the housing relative to each other in the vertical direction.

In particular, the fastening portion of the crossmember may comprise a hole of axis parallel to the vertical direction forming the housing, the fixing portion of the housing may comprise a head which extends in the vertical direction from an upper wall of said housing said head forming the fastener. This improves the accuracy of the relative positioning of the cross member and the housing. Independently or complementary to other modes of attachment as defined above, it is possible for the cross member to be snapped onto the housing. To do this, the fastening portion of the housing of at least one of the fastening torques may have a first surface facing the fastening portion of the crossbar of said fastening torque and a second surface facing away from the fastener. first surface, the fastening portion of the crossbar of said fastening torque may comprise a tongue which extends between said first and second surfaces and which has a fastening portion in contact with said second surface. Furthermore, to improve the compactness of the underbody, the fastening portion of the cross member of at least one of the fastening torques may comprise at least one support member adapted to come into contact with a support zone formed on the fastening portion of the housing of said fastening torque. The first section of at least one of the slides may have a substantially U-shaped cross section comprising a core and two wings connected by the core, the housing of the adjustment mechanism may be disposed between said flanges, said first section having at least one passage window which is adapted to allow the passage of one of the fastening portions of the housing and the crossbar of the fastening torque. To improve the overall rigidity of the underbody and allow the recovery of force, particularly in the event of impact, the fastening portion of the crossmember may comprise at least one insert, said first profile comprising at least one orifice adapted to receive with play. said insert.

To improve the coaxiality in the transmission chains, each transmission chain can extend from the motor to a free end guided in rotation on one of the housings. Furthermore, each transmission chain may comprise a shaft guided in rotation on the crosspiece. According to another aspect, the invention relates to a vehicle seat comprising a seat mounted on a base as defined above. Other objects and advantages of the invention will appear on reading the description which follows, made with reference to the accompanying drawings in which: - Figure 1 is a schematic representation in side view of a vehicle seat mounted on a floor FIG. 2 is a perspective representation of a base of the seat of FIG. 1, according to a first embodiment, FIG. 3 is a partially exploded perspective view of a guide rail of the underframe of FIG. FIG. 4a is an exploded perspective representation of an adjustment mechanism of the slide of FIG. 3; FIG. 4b is a perspective representation of a casing of the adjustment mechanism of FIG. 4a, FIG. is a perspective representation of a cross member of the base of FIG. 2, seen from a first side,

FIG. 6 is an enlarged perspective view of a free end of the first side of the cross member of FIG. 5; FIG. 7 is a perspective view of the cross member of FIG. FIG. 8 is an enlarged perspective view of a free end of the second side of the cross member of FIG. 5; FIGS. 9 and 10 are enlarged perspective views illustrating two steps of mounting and fixing the first 5 to the housing of FIG. 4b, FIG. 11 and 12 are representations similar to those of FIGS. 5 and 6 of a cross member of a base according to a variant of the first embodiment; FIG. 13 is a perspective view of the housing of the underbody adjustment mechanism according to the variant of the first embodiment; FIG. 14 is a perspective representation of a first section of the basement slide according to the variant of the first embodiment, - Figure 15 is a partial perspective representation of a first variant of a second embodiment of the base of the seat of Figure 1, - Figure 16 is a representation. in perspective of the first profile of the underbody slide of FIG. 15, - FIG. 17 is a perspective representation of the housing of the underbody adjustment mechanism of FIG. 15, FIG. 18 is a partial perspective representation of the Figs. 19 and 20 are enlarged perspective views illustrating two stages of mounting and securing the cross member of Fig. 18 to the housing of Fig. 17; Fig. 21 is a cross-section of the underbody of Fig. 15; perspective view of the cross member of a second variant of the second embodiment of the base of the seat of FIG. 1, FIG. An enlarged perspective view of the attachment of the cross member of FIG. 21 to the housing of the adjustment mechanism; FIG. 23 is a partial perspective representation of a third embodiment of the underbody of the seat of FIG. FIG. 24 is a perspective view of the first profile of the underbody slide of FIG. 23; FIG. 25 is a perspective view of the housing of the underbody adjustment mechanism of FIG. 23; FIG. 26 is a representation of FIG. In perspective of the underbody cross member of FIG. 23, FIGS. 27 and 28 are enlarged perspective views illustrating two steps of mounting and securing the cross member of FIG. 26 to the housing of FIG. FIG. 29 is a partial perspective representation of a fourth embodiment of the underbody of the seat of FIG. 1; FIG. 30 is a perspec representation; Fig. 31 is a perspective view of a free end of the underbody cross member of Fig. 29; Fig. 32 is an enlarged perspective view illustrating the embodiment of the underbody adjustment mechanism of Fig. 29; fixing the end of the crosshead of FIG. 31 to the housing of FIG. 30. In the figures, the same references denote identical or similar elements.

FIG. 1 represents a seat 1 of a vehicle, for example an automobile, comprising a seat 2 mounted on a floor 4 of the vehicle, and a backrest 3 carried, possibly in an articulated manner, by the seat 2.

The seat 1 is mounted on the vehicle so that it can be moved relative to the floor 4 in a substantially horizontal longitudinal direction X. In particular, the seat 2 is mounted on a base 5 for adjusting the position of the seat 2 relative to the floor 4 in the longitudinal direction X. In Figure 2, the base 5 comprises: - two parallel rails 6 which extend in the longitudinal direction X and which are spaced from each other in a transverse direction Y substantially horizontal and perpendicular to the longitudinal direction X, the slides 6 having respectively two internal faces facing each other; adjustment of the longitudinal position of the seat 2, - a crossbar 70 which extends between the rails 6 in the transverse direction Y. Here also defines a vertical direction Z perpendicular to the longitudinal direction X and the transverse direction Y.

In a first embodiment shown in Figures 2 to 10, each slide 6 comprises first 7 and second 8 sections mounted sliding relative to each other in the longitudinal direction X. In Figure 1, the first section 7, mobile, is secured to the seat 2, and the second section 8, fixed, is secured to the floor 4. As shown in Figure 3, the fixed section 8 has a substantially U-shaped cross section comprising: - a bottom 11 substantially in a horizontal plane (X, Y),

9 - an inner wing 10 and an outer wing 12 which each extend from the bottom 11 substantially in lateral planes (X, Z) spaced apart from each other in the transverse direction Y, each of the inner wings 10 and outer 12 of the fixed section 8 extending inwardly by a flap 13 forming a raceway. Similarly, the movable section 7 also has a substantially U-shaped cross section comprising: - a core 15 substantially in a horizontal plane (X, Y), - an inner flange 14 and an outer flange 16 which each extends from the web 15 substantially in lateral planes (X, Z) spaced apart from each other in the transverse direction Y, with a transverse spacing smaller than that of the lateral planes in which the inner wings 10 extend. and outer 12 of the fixed section 8, each of the inner and outer wings 14 and 14 of the movable section 7 extending outwardly by a flange 17 forming a rolling track. In the first embodiment, it is expected that the inner flange 10 of the fixed section 8 has a vertical dimension smaller than that of the outer flange 25 12 of said section 8 and that the inner flange 14 of the movable section 7 has a dimension vertical greater than that of the outer flange 16 of said section 7. Moreover, as shown in Figure 3, in the same transverse plane (Y, Z), the movable section 7 30 has an opening 18 forming an open passage window in the vertical direction Z, of substantially rectangular shape, formed in the core 15, and an opening 19 in the transverse direction Y, of substantially circular shape, formed in the inner flange 14. The inner flange 14 also has two notches 20 arranged in radii of the opening 19.

The inner flange 14 of the movable section 7 also comprises two substantially circular holes 21, arranged on either side of the opening 19, and two orifices 22 on either side of the holes 21. The opening 19, the holes 21 and the orifices 22 may be substantially aligned in the longitudinal direction X. As shown in Figure 2, the movable section 7 is mounted on the fixed section 8, the inner and outer wings 12 and 12 of the fixed profile 8 flanking the wings internal 14 and outer 16 of the movable section 7, the rolling tracks cooperating to form raceways in which sliding members, such as balls, are arranged to allow the sliding of the movable section 7 relative to the fixed profile 8. The bottom 11 is fixed to the floor 4, the core 15 placed at a distance from the bottom 11 is fixed to the seat 2. An interior space 9 is thus formed between the movable section 7 and the fixed profile 8, the passage window 18 making communi place the interior space 9 with the outside.

The adjustment system comprises two adjustment mechanisms, one of which is visible in FIGS. 3 and 4, each of which is received in the interior space 9 of one of the slides 6 in order to be able to move the mobile section 7 with respect to the fixed profile. 8.

The following description is made with the adjustment mechanism of one of the slides 6, it being understood that this description is transferable to the adjustment mechanism of the other slide 6. As shown in FIG. 3, the adjustment mechanism comprises a screw 25 which extends along an axis X 0 parallel to the longitudinal direction X and which is secured by its ends to the bottom 11 of the fixed profile 8, a nut 26 which is engaged on the screw 25 and which can be rotated around the axis X0, as explained below, so as to be displaced on the screw 25 in the longitudinal direction X.

In Figure 4a, the nut 26 has an external toothing on an outer surface. An endless screw 27 arranged transversely with respect to the nut 26 has a thread engaged with the external toothing of the nut 26. The endless screw 27 internally comprises an axial housing 28, open on the side of the inner face of the 6. As shown in Figures 4a and 4b, the adjustment mechanism further comprises a housing 30 on which the nut 26 and the worm 27 are pivotally mounted. In particular, the housing 30, made for example in two nested housing halves, comprises two transverse walls 31 perpendicular to the longitudinal direction X and surrounding the nut 26 in the longitudinal direction X. Each transverse wall 31 has an internal lateral edge, on the side of the inner face of the slide, and an outer side edge, on the side of an outer face of the slide opposite the inner face. Each transverse wall 31 also has a circular opening 32 coaxial with the axis X0 allowing the passage of the screw 25 and the rotational mounting about the axis X0 of the nut 26. The circular opening 32 of each transverse wall 31 is surrounded by abutments 33 protruding outwardly. The transverse walls 31 of the housing 30 are connected by two lateral walls 34 perpendicular to the transverse direction Y and which comprise, in an upper half, coaxial circular orifices 35 adapted to allow the rotation of the worm 27. the side wall 34 on the side of the inner face of the slideway 6, indentations 36 are formed near the orifice 35 and are arranged substantially along radii of the orifice 35.

The housing 30 comprises a horizontal upper wall 37 intended to be placed opposite the web 15 of the movable section 7 and the passage window 18. The housing 30 comprises a head 40 which extends in the vertical direction Z from the upper wall 37 and which is arranged, for example, centrally. The head 40, for example of substantially parallelepipedal shape, is provided with a housing which extends in the transverse direction Y. The housing comprises a horizontal portion 41, of substantially rectangular section, extended vertically by a slot 42 which extends over the entire transverse dimension of the horizontal portion 41 and which communicates said horizontal portion 41 with the outside in the vertical direction Z. In the first embodiment, the housing 30 may be placed between the inner and outer wings 14 and 14 the movable section 7 so that: - the head 40 of the housing through the passage window 18, the head 40 having an inner surface on the side of the inner face of the slide 6 and an outer surface on the side of the outer face of the slideway 6, and 20 - the housing 28 of the worm 27 is open on the opening 19 of the inner wing 14 and the cavities 36 are opposite the notches 20 of the inner wing 14. In FIGS. 3, 4a and 4b, the housing 30 is retained on the movable profile 7 by means of a support 45 open in the transverse direction Y on the side of the inner face of the slideway 6. The support 45, formed for example of a single plate cut and folded comprises two transverse walls 46. Each transverse wall 46 has a notch 47 30 which extends from a lower edge to allow the passage of the screw 25 and a rounded portion 48 protruding by to a top edge to be able to come into contact with the core 15 of the movable section 7. A side wall 49 connects two lateral edges facing the transverse walls 46. The side wall 49 is provided with a substantially central tongue 50 which

13 extends substantially vertically from an upper edge. Two lateral tabs 51 respectively extend perpendicularly to the transverse walls 46 from edges opposite to the side wall 49, away from each other. Each lateral leg 51 comprises a through hole 52. The housing 30 is placed in the support 45 so that the transverse walls 46 of the support 45 surround the transverse walls 31 of the housing 30. In FIGS. 3, 4a and 4b, a jacket 55 made of elastomeric material, open in the transverse direction Y may be interposed between the housing 30 and the support 45. The liner comprises two transverse walls 56 which respectively cover the transverse walls 31 of the housing 30. The transverse walls 56 of the liner 55 comprise openings 57 adapted to allow the passage of the screw 25 and to receive the stops 33.

The liner 55 also includes an upper wall 58 which covers the upper wall 37 of the housing 30. The upper wall 58 of the liner 55 is provided with a chimney in which the head 40 of the housing 30 is received.

To retain the housing 30 on the movable section 7, the lateral lugs 51 can be fixed to the inner wing 14 by means of the holes 52 of the lateral lugs 51 placed in correspondence with the holes 21 of the inner wing 14 to allow the passage a fastener, such as a rivet, a bolt or other. As a variant, it is possible to weld the lateral lugs 51 to the inner flange 14 of the mobile section 7 by transparency. The lateral wall 49 of the support 45 can thus be placed under the outer flange 16 of the movable section 7, the tongue 50 being engaged in a not shown opening of the outer flange 19 to form a stop.

The adjustment system is motorized and further comprises a motor 60, visible in particular in Figures 2, 5 and 6, which can be controlled by an actuator 61 provided on the seat 2 and which is connected to the adjustment mechanisms by chains of transmission. The transmission chains each comprise, for example, a shaft 62, in particular flexible, rotated by the motor 60. Each shaft extends from the motor 60 to a free end 63 shaped to engage the housing 28 of one of the screw without wine 27 and drive said screw without wine 27 in rotation. In doing so, the worm 27 in turn drives one of the nuts 26 in rotation, which nut 26 is thus displaced in the longitudinal direction X.

In the first embodiment, as shown in Figure 2, the motor 60 is carried by the cross member 70 and the shafts 62 are guided in rotation on the cross member 70. The cross member 70, made for example of plastic material, comprises first 71 and second 72 support members each made in one piece and each provided with a guide 73 in which are housed shafts 62. The first support member 71 may be shorter than the second support member 72 to support the motor 60. On 5, the first support member 71 has two horizontal ribs 78 disposed on either side of the guide 73 in the same horizontal plane (X, Y) and each connected by a free end to a transverse rib 79 in a transverse plane. (Y, Z). The guide 73 of the first support member 71 is tubular and extends in the transverse direction Y between a plate 75, motor side 60, and a support plate 76, slide side 6. The plate 75 and the support plate 76 extend into two lateral planes (X, Z) spaced from each other in the transverse direction Y.

The plate 75, of substantially square shape, is equipped with a plurality of arms 77, for example four, which extend from a peripheral zone of the plate 75 in the transverse direction Y. The guide 73 opens into the plate 75 by an opening not shown. In FIG. 6, the support plate 76, disposed at a free end of the first support member 71, has a circular opening delimited by an annular skirt 80 and through which the guide 73 can open towards the slideway 6. The support plate 76 also comprises one or more rods 81, two in FIG. 6, of rectangular section, which extend transversely so as to project beyond the skirt 80. The rods 81 are oriented so that the long side of their section extends along a radius of the section of the skirt 80. On either side of the skirt 80, the support plate 76 comprises two inserts 82 each made in the form of two flexible hooks opposed to one another. Above the skirt 80, the support plate 76 has a tab 83 which extends in the transverse direction Y. The tab 83 has a substantially inverted T-shaped section with a horizontal base and a vertical portion. One or more tabs 84, two disposed on either side of the base of the tab 83 in FIG. 6, extend from the support plate 76 in the transverse direction Y. Each tab 84 has a hooking part, for example in the form of a lug facing the lug 83 at a free end.

The skirt 80, the rods 81, the inserts 82, the tab 83 and the tongues 84 are sized and arranged on the support plate 76 so that: the skirt 80 and the rods 81 can cross the opening 19 and the notches 20 of the inner flange of the movable section 7, the inserts 82 may be received with clearance in the orifices 22 of the inner flange 14 of the movable section 7,

16 - the tab 83 can be nested in the housing of the head 40 of the housing 30, - the tongues 84 can be snapped onto the head 40.

In FIGS. 7 and 8, like the first support member 71, the second support member 72 comprises two horizontal ribs 78 disposed on either side of the guide 73 and connected to two transverse ribs 79. The guide 73 of the second support member 72 is formed of an alternating succession of upper and lower hemi-cylindrical troughs 87 in which one of the shafts 62 is threaded so as to be held in position. In the same way as for the first support member 71, the guide 73 of the second support member 72 extends between a substantially square plate 85, motor side 60, and an anchoring piece 86, sliding side 6. The plate 85 and the anchoring piece 86 extend in two lateral planes (X, Z) spaced apart from each other in the transverse direction Y.

In FIG. 8, the anchoring piece 86, disposed at a free end of the second support member 72, comprises a skirt 80, a tab 83 and tabs 84 similar to those of the support plate 76 of the first support member 71. skirt 80, the tab 83 and the tabs 84 are dimensioned and arranged to cooperate in the manner indicated above with the inner flange 14 of the movable section 7 and the housing 30 of the corresponding slideway 6. The motor 60 is arranged between the arms 77, which are then suitably fixed, for example by snapping, to the plate 85 of the second support member 72. The motor is held between the arms by appropriate members provided on the plates 75, 85. According to the invention, the cross member 70 is fixed directly to the housings 30 of the adjustment mechanisms. In particular, upper halves of the housings 30 each including in particular the head 40 respectively form fixing portions of the housings 30. The free end of the crosspiece 70 comprising the support plate 76, the skirt 80, the rods 81, the inserts 82 , the tab 83 and the tabs 84 form a fastening portion of the cross member, and the free end of the cross member 70 comprising the anchor 86, the skirt 80, the tab 83 and the tabs 84 forming another part of fixing the crossbar. The base 5 thus comprises two fixing torques each composed of a fixing portion of one of the housings and one of the fastening portions of the cross member. With reference to FIGS. 9 and 10, the assembly of the cross-member 70 to one of the housings 30 is described.

This description is made with the first support member 71 of the cross member 70, it being understood that a similar assembly can be made for the second support member 72 of the cross member 70 on the other slideway 6.

The free end of the cross member 70 comprising the support plate 76 is brought towards the inner face of the slideway 6. The support plate 76 is substantially parallel to the inner wing 14 of the movable section 7. The skirt 80 and the rods 81 are placed respectively facing the opening 19 and the notches 20 of the inner flange 14 of the movable section 7. The free end 63 of the shaft 62 is placed facing the housing 28 of the worm 27. The leg 83 of the support plate 76 is positioned facing the housing of the head 40 (Figure 9). As shown in FIG. 10, by moving the crossmember 70 relative to the housing 30 in the transverse direction Y, the tab 83 of the crossmember 70 is nested in the housing of the head 40 of the housing 30, the base of the leg 83 extending in the horizontal portion 41 and the vertical portion extending into the slot 42. The tab 83 then constitutes a fastener formed

18 on the fastening portion of the cross member and cooperating by fitting with the housing formed on the fixing portion of the housing, in particular on the head 40. The tabs 84, spaced apart during the displacement of the lugs on transverse surfaces of the head 40, extend between the inner and outer surfaces of the head 40, the lugs being positioned opposite the support plate 76 in contact with the outer surface of the head 40. The fastening portion of the cross member can thus being snapped onto the head 40 of the housing 30. Moreover, the free end 63 of the shaft 62 passes through the opening 19 to be fitted into the housing 28 of the worm 27, the free end 63 is thus guided in rotation in the orifices 35 of the housing 30 via the worm 27. The skirt 80 and the rods 81 respectively pass through the opening 19 and the notches 20 of the inner flange 14 of the movable section 7 and come into contact on the lateral wall 34 of the housing 30, the rods 81 being placed on the cavities 36. The skirt 80 and the rods 81 may thus each constitute a support member in contact on a bearing zone, embodied, for example, by one of the imprints 36, formed on the side wall 34 of the housing 30.

The inserts 82 of the support plate 76 are then received with clearance in the orifices 22 of the inner flange 14 of the movable section 7. The inserts 82 can thus come into contact with the edges of the orifices 22 in the event of impact, in order to ensure a recovery of efforts.

A variant of the base according to the first embodiment is shown in Figures 11 to 14. The base according to this variant is similar to the base described above. As shown in Figures 11 and 12, in this variant, the attachment portions of the first 71 and second 72 support members, each comprise a semicylindrical skirt 80a. Above the skirt 80a,

Each fixing part comprises the tab 83 and two tabs 84a snapping on the head 40 of the housing, arranged on either side of the tab 83. The tabs 84a each have a rigid base portion, composed of parallel ribs interconnected, and an end portion, folded towards the tab 83 and forming a flexible hooking portion adapted to come into contact with the outer surface of the head 40 of the housing 30.

Each fixing portion further comprises second tabs 83a which extend in the transverse direction Y on either side of the skirt 80a. Bridges 100 connect the second legs 83a to the skirt 80a.

The attachment portion of the first support member 71 further comprises two arms 101 arranged longitudinally on either side of the support plate 76. One of the arms 101 has at one free end a flap 102 which extends in the direction transverse Y so as to come into contact with the outer surface of the movable section 7 in case of impact. The other arm 101 comprises at one free end an insert 82a in the form of a hook having a rigid base portion, formed of perpendicular ribs, and an end portion, flexible, folded outwardly. In FIG. 13, the housing 30 similar to the housing described above further comprises, in the upper half, a recess 103 formed on each of the transverse walls 31. Each recess 103 extends from the internal lateral edge of one of the walls. transversely 31, for example over the entire transverse dimension of the housing 30. The recesses 103 form housings of the fastening portion of the housing, wherein the second tabs 83a of one of the fastening portions of the cross member may be engaged. In the variant shown, the recesses 103 constitute additional housings to that of the head 40.

Provide that one or more of these recesses constitute the housings of the fixing part of the housing. The movable section 7 adapted for fixing the cross member 70 of Figures 11 and 12 on the housing 30 of Figure 13 is shown in Figure 14. This movable section 7 is similar to the movable section described above. The movable section 7 has notches 20a arranged to allow the passage of the second legs 83a and the bridges 100 of the cross member 70. In this way, the second legs 83a can be engaged in the recesses 103 of the housing 30 and the skirt 80a and the bridges 100 may come into contact on the side wall 34 of the housing 30. The movable section 7 may also have a single orifice 22 adapted to receive with clearance the insert 82a of the cross member 70. In connection with Figures 15 to 20, discloses a second embodiment which, like the first embodiment, provides, for each pair of attachment, at least one fastening element on the fastening portion of the cross member and at least one housing on the fastening portion of the housing, which extend in the transverse direction Y and cooperate by fitting. The second embodiment essentially differs from the first embodiment in that the housing is a bore 97 which extends into the housing 30 and which has an opening on the side wall 34 of the housing 30 and in that the fixing is a pin 96 fitted into the bore 97. Furthermore, in this embodiment, the passage window of the movable section 7 allows the passage of the pin 96 of the fastening portion of the cross member. In FIGS. 15 to 20, the movable section 7, visible in particular in FIG. 16, comprises the openings 18 and 19 and a first hole 95 formed on the inner flange 14, open in the transverse direction Y and forming a first window of passage. A second hole 95 forming a second passage window may be formed on the inner flange 14 so that the first and second passage windows are disposed on either side of the opening 19.

In FIG. 17, the housing 30 whose head 40 is reduced to a portion of a cylinder comprises, in the upper half, two bores 97 which extend along an axis parallel to the transverse direction Y. The bores 97 each open with a opening on the side wall 34 of the housing 30 and are arranged on either side of the orifices 35 to be placed in correspondence with the through windows 95. The cross member 70 shown in Figure 18 is similar to that described in connection with the first embodiment. Each of the attachment portions is provided with two pins 96 which respectively extend from the transverse ribs 79 in the transverse direction Y. The pins 96 are placed on each side of the free end 63 of the shaft 62 so that to be able to pass through the passage windows 95 of the movable section 7 and be nested in the bores 97 of the housing 30. In connection with FIGS. 21 and 22, the assembly of the cross member 70 to one of the housings 30 is described. This description is made with the second support member 72, it being understood that a similar assembly is made for the first support member 71 on the other slide 6. The free end of the crossbar 70 comprising the pins 96 is brought to the internal face of the slide 6. The free end of the guide 73 is placed facing the opening 19 of the inner flange 14 of the movable section 7. The free end 63 of the shaft 62 is placed opposite the housing 28 of the vi The spindles 96 are positioned opposite the passage windows 95 of the movable section 7 (FIG. 19).

As shown in FIG. 20, by moving the crossmember 70 relative to the housing 30 in the transverse direction Y, the free end of the guide 73 passes through the opening 19 and bears against the side wall 34 of the housing 30. free end 63 of the shaft 62 through the opening 19 to be fitted into the housing 28 of the worm 27. The pins 96 of the cross member 70 are engaged in the bores 97 of the side wall 34 of the housing 30, to 95. In a second variant shown in Figures 21 and 22, the cross member 70 comprises a tube 90, for example metal, having a curved zone, and a body 91 sheet positioned in the bent zone. The motor 60 can be immobilized on the body 91, for example by clipping into notches formed in side flanges in planes (X, Z) which frame the motor 60 in the transverse direction Y. The cross member 70 comprises, at each its free ends, a tip provided with the pins 96. Each end also comprises a central bore arranged between the pins 96 and wherein the shaft 62 is fitted. The mounting of this cross member 70 is similar to that described in relation to the first variant.

A third embodiment shown in FIGS. 23 to 28, differs from the previously described embodiments essentially in that the crossmember 70 and the housing 30 are adapted so that the assembly of the crossmember 70 to the housing 30 is obtained by moving the crosswise 70 relative to the housing 30 in the vertical direction Z. To do this, the fastening element and the housing of each fastening torque extend in the vertical direction Z. In addition, the third embodiment differs from the other embodiments described in that, for each fastening torque, the fastening element is

23 provided on the fastening portion of the housing and the housing is provided on the fastening portion of the cross member. As shown in Figure 23, the movable profiles 7 and fixed 8 and the adjustment mechanism of each slide 6 are similar to those of the first embodiment. In FIG. 24, the movable profile 7 differs, however, from that described above in that it does not have the holes 21. In this embodiment, it is provided, without being limited thereto, that the support 45 is welded by transparency on the inner flange of the movable section 7. In FIG. 25, the housing 30 differs from the housing 30 described above in that the head 40 is substantially cylindrical and has a vertical dimension greater than that of the head of the first embodiment. . In the third embodiment, the head 40 has, moreover, two flats in lateral planes (X, Z) and an external thread on rounded portions of its outer surface. In FIG. 26, the crossmember 70 is similar to that of the second variant of the second embodiment except for the free ends of the crossmember 70.

Indeed, the free ends of the tube 90, which can be flattened in a horizontal plane (X, Y) and which constitute the fixing portions of the crosspiece, each comprise a hole 92 of axis parallel to the vertical direction Z. The holes 92 form the housing couples fixing. In particular, one of the free ends may have a substantially circular hole 92 ensuring the positioning of the cross member 70 and the other free end may have an oblong hole 92 ensuring the catching of any dimensional dispersions. In relation with FIGS. 27 and 28, the assembly of the cross member 70 is described in one of the housings 30.

This description is made with the free end having the circular bore, it being understood that a similar assembly is made for the other end. The free end of the cross member 70 is brought above the web 15 of the movable section 7, the hole 92 being disposed facing the head 40 (Figure 27). By moving the cross member 70 relative to the housing 30 in the vertical direction Z, the head 40 passes through the hole 92. The head 40, which then forms the fastening element of the fixing torque, can be retained in the bore by means of a fixing member, such as a nut 93 engaged on the external thread of the head 40 (Figure 28). As a variant, the head 40 can be retained by friction by means of a fixing member, possibly integral with the free end of the cross-member 70. Prior to or after the engagement of the head 40 in the hole 92, the flexible shaft 62 is deformed to place the free end 63 in the housing 28 of the worm 27. Figures 29 to 32 show a fourth embodiment of the underbody 5 of the seat of Figure 1. This embodiment comprises many elements which are similar to those of the previous embodiments and which will not be described again in detail. The slides 6 are similar to those of the previous embodiments and comprise movable profiles 7 and fixed 8 having a cross section substantially U-shaped.

As shown in Figure 29, it is expected, however, that the inner and outer wings of the fixed profile 8 have the same vertical dimension and that the inner and outer wings of the movable section 7 has the same vertical dimension.

Furthermore, as shown in FIG. 29, in the same transverse plane (Y, Z), the mobile section 7 comprises, in the vicinity of one end, openings

25 105, of substantially rectangular shape, formed in the core and in the wings. The adjustment system is motorized as described above and comprises two adjustment mechanisms each received in the interior space 9 of one of the slides 6 to be able to move the movable section 7 relative to the fixed profile 8. In the fourth embodiment , it is provided that the screw 25 can be rotated about the axis X0, as explained below, and that the nut 26 which is engaged on the screw 25 is appropriately secured to the fixed profile 8. As shown in Figure 30, the adjustment mechanism further comprises a housing 106 on which one end of the screw 25 is rotatably mounted about the axis X0. The housing 106 comprises in particular a head 107, for example of substantially parallelepipedal shape, which extends in the vertical direction Z from an upper wall 108. The housing 106 encloses a set of transmission members adapted to transmit the rotational movement of the motor 60 to the screw 25. The transmission members may for example comprise a pinion with external toothing secured to the end of the screw 25 and a worm screw similar to the worm 27 and arranged in the same way, the screw Endless having a thread engaged with the external toothing of the pinion. The free end of each shaft 62 can be engaged in a sleeve 109 and be connected to the transmission members, in particular to the screw without wine to drive it in rotation. In doing so, the worm in turn drives the screw 25 in rotation in the nut 26 fixed. This results in a displacement in translation in the longitudinal direction X of the screw 25 relative to the nut 26.

In FIGS. 29 and 30, the housing 30 placed between the inner and outer wings of the fixed profile 8, at one end and outside the mobile section 7, is retained on the mobile section 7 by means of a cylindrical member 110 in the openings 105 of the movable section 7. In this way, the movable section 7 is moved together with the screw 25 relative to the nut 26 and the fixed profile 8. The motor 60 is carried by a cross member 70 similar to that of the first embodiment, the cross member 70 having free ends adapted to be snapped respectively on the heads 107 of the housings 106. As shown in Figure 31, the fastening portions of the cross member comprise tabs 84a similar to that described in relationship with the variant of the first embodiment. In FIG. 32, the crossmember 70 moved relative to the housing 106 in the transverse direction Y can be snapped onto the head 107 of the housing 106.

Claims (19)

Vehicle underbody (5), comprising: - two rails (6) each comprising first (7) and second (8) sections mounted sliding relative to each other in a longitudinal direction (X), and an adjusting mechanism comprising: - a housing (30; 106) retained on the first profile (7), - first and second members formed by a screw (25) which extends according to one axis (XO) parallel to the longitudinal direction (X), and the other by a nut (26) which is engaged on the screw (25), said first member being rotatably mounted about the axis (XO) on the housing (30; 106), and said second member being secured to the second profile (8), - a cross member (70) extending between the rails (6) in a transverse direction (Y) perpendicular to the longitudinal direction ( X), - a motor (60) carried by the cross member (70) and two transmission chains adapted to drive in rotation the first member of each an adjustment mechanism, said underbody (5) being characterized in that the crossbar (70) is directly attached to the housing (30; 106) of each adjustment mechanism. The underbody (5) according to claim 1, comprising two fastening torques each composed of a fastening portion formed on an upper half of one of the housings (30; 106) and a fastening portion formed at a free end of the crossbar (70), the fixing portions of the housing and the crossbar of each fastening torque being fixed directly to one another. The underbody (5) according to claim 2, wherein at least one of the fastening torques comprises at least one fastener (40; 83,83a; 96) and at least one housing (41,42; 97; 103) adapted to receive the fastener (40; 83; 83a; 96), said fastener (40; 83; 83a; 96) and said housing (41, 42; 92; 97; 103); being formed on one of the fastening portion of the housing and the other on the fastening portion of the cross member. 4. Base (5) according to claim 3, wherein the fastening element (83, 83a; 96) and the housing (41, 42; 97; 103) extend in the transverse direction (Y). The underbody (5) according to claim 4, wherein the housing (41, 42; 97; 103) is formed on the housing attachment portion and the attachment member (83, 83a; 96) is formed on the housing fastening part of the crossbar. The underbody (5) according to claim 5, wherein the fixing portion of the housing comprises a head (40) which extends in a vertical direction (Z) perpendicular to the longitudinal (X) and transverse (Y) directions from a upper wall (37) of said housing (30), the housing (41, 42) being formed in the head (40), the fixing member being a tab (83) fitted in the housing. 7. Subframe (5) according to claim 5 or 6, wherein the housing (30) comprises a transverse wall (31) perpendicular to the longitudinal direction (X) and which has an internal lateral edge near the fixing portion of the cross member, the housing being a recess (103) formed on said transverse wall (31) of the housing (30) and extending from said inner lateral edge, the fastening element being a tab (83a) engaged in the recess (103). 8. Base (5) according to any one of claims 5 to 7, wherein the housing (30) comprises a side wall (34) perpendicular to the transverse direction (Y), the housing being a bore 29 (97) which extends into the housing (30) and has an opening on said side wall (34), the fastener being a pin (96) fitted into the bore (97). 9. Base (5) according to claim 3, wherein the fastening element (40) and the housing (92) extend in a vertical direction (Z) perpendicular to the longitudinal direction (X) and transverse (Y). 10. Underbase (5) according to claim 9, wherein the fastening portion of the cross member comprises a hole (92) of axis parallel to the vertical direction (Z) forming the housing, the fixing portion of the housing comprises a head. (40) extending in the vertical direction (Z) from an upper wall (37) of said housing (30), said head (40) forming the fastener. 11. Subframe (5) according to any one of claims 2 to 10, wherein the fastening portion of the housing of at least one of the fastening torques has a first surface facing the fastening portion of the cross member of said fixing torque and a second surface oppositely oriented to the first surface, the fastening portion of the crossmember of said fastening torque comprises a tongue (84; 84a) extending between said first and second surfaces and having a gripping portion in contact with said second surface. 12. Subframe (5) according to any one of claims 2 to 11, wherein the fastening portion of the cross member of at least one of the fastening torques comprises at least one support member (80; 81; 100) adapted to come into contact with a bearing zone (36) formed on the fastening portion of the housing of said fastening torque. 13. Subframe (5) according to any one of claims 2 to 12, wherein the first section (7) of at least one of the slides has a substantially U-shaped cross section comprising a core (15). and two wings (14, 16) connected by the web (15), the housing (30) of the adjustment mechanism is disposed between said wings (14, 16), said first section (7) having at least one passage window (18; 95) which is adapted to allow the passage of one of the fastening portions of the housing and the crossbar of the fastening torque. 14. Subframe (5) according to claim 13, wherein the fastening portion of the cross member comprises at least one insert (82; 82a), said first section (7) having at least one orifice (22) adapted to receive with play. said insert (82). 15. Underbase (5) according to any one of claims 1 to 14, wherein each transmission chain extends from the motor (60) to a free end guided in rotation on one of the housings (30; 106). 16. Subframe (5) according to any one of claims 1 to 15, wherein each transmission chain comprises a shaft (62) guided in rotation on the cross member (70). 17. Subframe (5) according to any one of claims 1 to 16, wherein the first member is formed by the screw (25) and the second member is formed by the nut (26). 18. Subframe (5) according to any one of claims 1 to 16, wherein the first member is formed by the nut (26) and the second member is formed by the screw (25). 19. Vehicle seat (1) comprising a seat (2) mounted on a base (5) according to any one of claims 1 to 18.35