FR2921022A1 - Adjustment mechanism for motor vehicle seat's slide, has connection units connecting housing parts with each other, where connection units exert prestress on flanges by projecting flanges resiliently towards nut in longitudinal direction - Google Patents

Abstract

The mechanism (12) has a nut (14) tightened on a screw (13) and mounted in a housing. The housing has assembled housing parts (18, 19) provided with end flanges (20) perpendicular to longitudinal direction (X). The flanges are arranged on both sides of the nut and crossed by the screw. Connection units (35) connect the parts with each other, and exert prestress on the flanges by projecting the flanges resiliently towards the nut in the longitudinal direction, where the parts are molded by Derlin(RTM: homopolymer acetal) material.

Description

Screw adjustment mechanism, slide comprising such an adjustment mechanism and seat comprising such a slide.

The present invention relates to screw adjustment mechanisms, slides having such mechanisms and seats with such slides. More particularly, the invention relates to a screw adjusting mechanism, comprising a screw which extends in a longitudinal direction and a nut screwed onto said screw, the nut being rotatably mounted in a housing which comprises two assembled housing parts, respectively comprising two end flanges substantially perpendicular to the longitudinal direction, said end flanges being disposed on either side of the nut and traversed by the screw. The document US-A-2006/0213302 describes an example of such a setting mechanism, in which the housing comprises four parts assembled by welding, which makes the assembly complex and difficult to achieve, especially since this welding is carried out with the housing mounted on the nut. When new, this mechanism has no longitudinal clearance between the housing and the nut, but during the lifetime of the mechanism, a longitudinal play inevitably reappears between the housing and the nut due to wear, which generates rattling phenomena and jolts during the use of the mechanism. The present invention is intended to overcome these disadvantages.

For this purpose, according to the invention, a control mechanism of the kind in question is characterized in that it further comprises a resilient connecting member which connects said two housing parts to one another by holding them together. , said connecting member exerting on the housing parts a prestressing elastically biasing the two end flanges towards the nut in the longitudinal direction. Thanks to these arrangements, the longitudinal clearances between the nut and the end flanges of the casing are made up elastically and throughout the life of the adjustment mechanism, even in case of wear, thanks to the elastic prestressing of the housing. the liaison body. This avoids some rattling noises, and improves the feeling of comfort and quality felt by the user, including ensuring a smooth actuation of the mechanism. In preferred embodiments of the adjustment mechanism according to the invention, one or more of the following arrangements may also be used. - The connecting member comprises a base which extends in the longitudinal direction between two flexible blades resiliently biasing the end flange of the housing parts to the nut; each elastic blade cooperates by interlocking with one of the end flanges; each elastic blade has a fork shape, comprising two lateral branches fitted respectively in two opposite lateral grooves formed in the corresponding end flange; Each elastic blade further comprises a base from which the two lateral branches of said blade extend, said base being fitted into an additional groove formed in the end flange, the additional groove joining the two lateral grooves. ; - Each housing part is retained on the connecting member by clipping the resilient blades; each elastic blade has a fork shape, comprising two lateral branches fitted respectively in two opposite lateral grooves formed in the end flange of one of the housing parts, the lateral branches of said elastic blade each having a free end and the free end of at least one of said lateral branches having a hook engaged by clipping on said end flange by retaining said housing part on the connecting member; each casing member furthermore comprises a lateral flange having a close end of the end flange of the other casing part, the free ends of the two lateral branches of each flexible blade being provided with a hook, one of the side branches of said flexible blade being engaged: in the lateral groove of the end flange 15 of one of the housing parts in the vicinity of the base, and in lateral contact with the end of the side flange of the other casing member in the vicinity of the hook of said lateral branch, and said hook being engaged by clipping on said end of the side flange by retaining said housing part on the connecting member; the connecting member is formed of a single piece, in sheet metal cut and folded; The two housing parts furthermore comprise respectively two lateral flanges substantially perpendicular to the end flanges and arranged on either side of a worm wheel, the worm wheel being rotatably mounted on the flanges lateral and meshing with an external toothing belonging to the nut for controlling a rotation of said nut; - The nut is rotatably mounted on the end flanges and said end flanges are applied by the connecting member abutting against two opposite end faces 35 belonging to the nut. Furthermore, another object of the invention is a slideway comprising a first slide element slidably mounted relative to a second slide element in said longitudinal direction, said slideway comprising an adjustment mechanism as defined above, the casing of which is fixed. to the first slide element and whose screw is secured to the second slide element. Advantageously, the housing may be mounted in a support integral with the first slide element, said support having two flaps framing the housing in the longitudinal direction. Finally, the invention also relates to a vehicle seat comprising a seat supported by at least one slide as defined above. Other features and advantages of the invention will become apparent from the following description of one of its embodiments, given by way of non-limiting example, with reference to the accompanying drawings. In the drawings: - Figure 1 is a schematic view of a seat 20 may include slides according to a first embodiment of the invention, - Figure 2 is a perspective view of the seat slides of Figure 1, - FIG. 3 is a perspective view of one of the slides of FIG. 2; FIG. 4 is a view similar to FIG. 3, showing the slide without the second slide element; FIG. In perspective of the slider adjustment mechanism of Figs. 3 and 4, Fig. 6 is an exploded and partially broken away view showing the adjustment mechanism of Fig. 5, with the support connecting this mechanism to the first slider member, FIG. 7 is a detailed perspective view of one of the parts forming the housing of the adjustment mechanism of FIGS. 5 and 6; FIG. 8 is a vertical sectional view of the slide of FIGS. 3 and 4, according to FIG. line VIII-VIII of FIG. 9, Figure 9 is a horizontal sectional view along the line IX-IX of Figure 8, Figure 9a is a detail view IXa of Figure 9, and Figures 10 and 11 are sectional views respectively along the lines. XX and XI-XI of Figure 9. In the different figures, the same references designate identical or similar elements. Figure 1 shows a motor vehicle seat 1 which comprises a backrest 2 carried by a seat 3 itself slidably mounted on the floor 4 of the vehicle, in a longitudinal direction X substantially horizontal. The seat 3 is connected to the floor 4 by two parallel rails 5, clearly visible in Figure 2. Each of these rails comprises first and second slide members 6, 7, formed by metal profiles respectively connected to the seat 3 and to the floor 4, which slide on one another in the X direction.

As represented in FIG. 2, the first slide members 6 may optionally comprise vertical attached wings 6a, allowing the seat 3 to be mounted. The adjustment of the slides 5 is motorized, and controlled for example by means of a push button. 8 (Figure 1) which controls the operation of an electric motor 9 visible in Figure 2, for example fixed to a cross member 10 integral with the first slide members 6 and the seat 3. The electric motor 9 drives in rotation by example two flexible 11 whose ends themselves drive adjustment mechanisms 12 respectively belonging to the two slides 5. Each adjustment mechanism 12 comprises a fixed screw 13 whose ends 13a (see Figures 3 and 4) are secured by any known means with the second slide element (only one of the ends 13a is visible in Figure 3). This screw 13 extends in the longitudinal direction X and the adjusting mechanism further comprises a nut 14 screwed onto the screw 13, as shown in particular in Figures 5 and 6. The nut 14 is centered on the longitudinal axis X0 the screw 13 and has an external toothing 15 which meshes with a worm wheel 16 rotatably mounted along an axis of rotation Yo parallel to a transverse direction Y, which is substantially horizontal and perpendicular to the longitudinal direction X. The wheel to worm 16 and the nut 14 are pivotally mounted in a casing 17 which may, for example, consist of two housing parts 18, 19 clearly visible in Figure 6. These two housing parts 18, 19, which can advantageously be identical to one another, may be molded for example of plastic material, in particular polyamide 6-6 (DELRIN or other) optionally reinforced with glass fibers or the like.

As can be seen in FIGS. 6 and 7, each of the housing parts 18, 19 may comprise an end flange 20 and a lateral flange 21. The end flange 20 extends substantially in a plane (Y, Z), where Z is a vertical axis, and the lateral flange extends substantially in a plane (Y, Z). Each end flange 20 comprises, in its lower part (in the position shown in the drawings), a planar inner bearing surface 22 in the center of which is provided a bearing 23, extended along the axis X0 by a through hole cylindrical 24 of smaller diameter, opening on the outer face 25 of the end flange. In addition, in the thickness of each end flange 20 are formed grooves opening outwardly parallel to the transverse plane (Y, Z), namely: - two opposite lateral grooves 26 opening outwardly in the direction transverse Y, and - a lower groove 27, clearly visible in Figures 10 and 11, opening downwards and joining together the lateral grooves 26. The lateral grooves 26 extend upwards to a rim 26a oriented towards the top (see Figures 6 and 10) Furthermore, as shown in Figure 7, the inner face of each end flange 20 has an indentation 28 in the upper part, separated from the bearing surface 22 mentioned above by a shoulder 29 facing up.

The lateral flange 21 of the same housing part extends only in the upper part of the housing part, substantially at the level of this indentation 28. The lateral flange has a flat inner face 30 in which is formed a circular recess 31 also opening downward, this recess 31 being extended by a circular through hole 32 opening laterally outwardly. The lateral flange 21 also forms a head 33 projecting upwards, and this lateral flange extends in the longitudinal direction X, opposite the end flange 20, by an end 34. This end 34 has a face terminal end 34a facing the end flange 20 of the other housing part in the longitudinal direction X. This end face protrudes with respect to a border 34b parallel to said end face and along said face. the end 34b being separated from said end face by a lateral shoulder 34c and an upper edge 34d (see Figures 5, 6, 9, 9a and 10).

As shown in FIGS. 5 and 6, the two housing parts 18, 19 are arranged head-to-tail so as to constitute the casing 17, and are held together by means of an elastic connecting member 35 which exerts on the said parts casing 18, 19 a prestressing in the longitudinal direction X, elastically biasing the two end flanges 20 of these housing parts to the nut 14. In: The example shown here, the connecting member 35 is formed of one piece, sheet metal cut and folded.

This connecting member comprises a substantially flat base 36, which extends in the plane (X, Y) and which extends 90 ° upwards, at its two axial ends, by two resilient flexible blades 37. The elastic blades 37 each extend in a plane close to the plane (Y, Z), but are slightly inclined towards each other. Each flexible blade 37 has for example a fork shape, comprising a base 38 which extends the base 36 upwards and two lateral branches 39 which extend upwards in the direction Z from the base 38, each up to at a free end. The free ends of the two lateral branches 39 of each flexible blade (or at least the free end of one of the branches 39) may be provided with a hook 40 projecting inwardly.

The base 38 of each flexible blade is engaged in the lower groove 27 of the lateral flange 20 of one of the housing parts 18, 19 (see FIGS. 10 and 11), whereas the two lateral branches 39 of the flexible blade are engaged in the lateral grooves 26 of the end flange (see Figures 8 and 9). The hook 40 of one of the side branches 39 is clipped on the flange 26a of the end flange corresponding to the flexible blade 39, while the hook 40 of the other side branch 39 of the same flexible blade is clipped on the rim 34d from the end of the side flange of the other housing part (see Figure 10). Thanks to this engagement and clipping, the two housing parts 18, 19 are firmly held in place, and thanks to the flexibility and the initial inclination of the flexible blades 37, the end flanges 20 of the two housing parts are urged resiliently towards each other, so that their inner bearing faces 22 are respectively bearing against opposite end faces 14a of the nut (see Figures 10 and 11). When the adjustment mechanism 12 is assembled, the nut 14 is thus mounted without play in the casing 17, said nut being rotatably mounted by means of two opposite journals 14b of said nut which are fitted into the abovementioned bearings 23 of the end flanges. The screw 13 passes through the holes 24 of the end flanges, the screw 13 slides in the holes 24 with a reduced clearance (for example less than 0.3 mm), so that the holes 24 guide the screw. In addition, in this assembled state, the worm wheel 16 is disposed in a housing formed by the recesses 31 of the two lateral flanges 21 (see FIG. 9) and is rotatably mounted about the axis Yo on said lateral flanges. , for example by means of two bearing rings 32a, which are fitted into the circular holes 32 of the lateral flanges 21 and in which they are themselves fitted with pins 16a belonging to the fine end screw wheel 16. When the casing 17 is assembled, the end 34 of the side flange of one of the housing parts is arranged opposite the indentation 28 of the end flange of the other housing part. As represented in FIG. 9a, the upper end of one of the lateral branches 40 is then disposed near the edge 34b of this end 34, but this edge 34c is set back with respect to the axial face of the lateral groove 26 which receives the other branch 40 of the same flexible blade 37, so that the flexible blade in question only biases one of the housing parts towards the nut, the other housing part being urged elastically towards the nut by the other flexible blade.

In addition, a clearance is provided in the X direction between the end face 34a of each lateral flange 21 and the corresponding indentation 28, which ensures that the inner bearing faces 22 of the end flanges are well supported. against the end faces 14a of the nut. Finally, note that the pivoting mounting of the worm wheel 16 on the side flanges 21 allows a certain relative displacement between the two housing parts 18, 19, to allow the connecting member 35 to eliminate any axial play existing between the nut 14 and the end flanges 20 of the two housing parts. Moreover, as shown in FIG. 4, the first slide element 6 may have a generally U-shaped shape, comprising a horizontal upper wall 42 extended downwards by two lateral wings 43, which may themselves be extended, towards The casing 17 of the adjustment mechanism 12 can be accommodated for example in a recess 45 cut in the upper face 42 and in at least a portion of the lateral wings 43 of the first element of the first element. Slide 6. The casing 17 can be retained in this recess by means of a support 46 which can be made for example of folded and cut sheets and which is clearly visible in FIGS. 3 and 6. This support 46 can for example have a upper face 47 with a through recess 48 and this upper face is extended, at its two ends in the longitudinal direction X, by two flaps 49 which extend towards the lower face in the plane (Y, Z) and which each have a U-shape. The upper face 47 of the support 46 can also be extended, on one of its lateral edges, by a tab 51 folded downwards, in the plane (X, Z). This tab may for example extend on either side of the recess 45 of the first slide member 6 and be welded to said first slide member on each side of this recess. When the adjusting device 12 is mounted on the slideway 5, as shown in FIGS. 3 and 8, the heads 33 of the lateral flanges 21, which are arranged in mutual correspondence and form a single outwardly protruding protrusion, are nested in the recess 48 of the upper wall 47 of the support, while the flaps 49 of the support 46 enclose the outer faces 25 of the end flanges, the branches 50 of its flaps passing on either side of the screw 13 (see Figures 10 and 11).

Claims (14)

1. Screw adjustment mechanism, comprising a screw (13) extending in a longitudinal direction (X) and a nut (14) screwed onto said screw, the nut (14) being rotatably mounted in a housing (17). ) which comprises two assembled housing parts (18, 19), respectively comprising two end flanges (20) substantially perpendicular to the longitudinal direction (X), said end flanges (20) being arranged on either side of the nut (14) and traversed by the screw (13), characterized in that it further comprises a connecting member (35) elastic which connects to each other said two housing parts (18, 19) by holding them together, said connecting member (35) exerting on the housing parts (18, 19) a prestressing elastically biasing the two end flanges (20) towards the nut (14) in the longitudinal direction (X). 2. Mechanism according to claim 1, wherein the connecting member (35) comprises a base (36) extending in the longitudinal direction (X) between two flexible blades resiliently biasing the end flanges (20) of the crankcase parts to the nut. 3. Mechanism according to claim 2, wherein each elastic blade (37) cooperates by interlocking with one of the end flanges (20). 4. Mechanism according to claim 3, wherein each elastic blade (37) has a fork shape, comprising two lateral branches (39) respectively engaged in two opposite lateral grooves (26) formed in the corresponding end flange. 5. Mechanism according to claim 4, wherein each elastic blade (37) further comprises a base (38) from which extend the two lateral branches (39) of said blade, said base (38) being nested in an additional groove (27) formed in the end flange (20), the additional groove (27) joining the two lateral grooves (26). 6. Mechanism according to any one of claims 2 to 5, wherein each housing part (18, 19) is retained on the connecting member (35) by clipping the resilient blades (37). 7. Mechanism according to claim 6, wherein each elastic blade (37) has a fork shape, comprising two lateral branches (40) respectively engaged in two opposite lateral grooves (26) formed in the end flange (20) d one of the housing parts, the lateral branches (40) of said elastic blade each having a free end and the free end of at least one of said lateral branches having a hook (40) engaged by clipping on said end flange (20) retaining said housing member on the connecting member (35). 8. Mechanism according to claim 7, wherein each housing part (18, 19) further comprises a lateral flange (21) having one end (34) adjacent to the end flange of the other housing part (18, 19), the free ends of the two lateral branches (39) of each flexible blade (37) being provided with a hook (40), one of the lateral branches (39) of said flexible blade (37) being engaged: in the lateral groove (26) of the end flange of one of the housing parts (18, 19) in the vicinity of the base (36), and in lateral contact with the end (34) of the lateral flange of the another housing part in the vicinity of the hook (40) of said lateral branch (39), and said hook (40) being engaged by clipping on said end (34) of the lateral flange by retaining said housing part on the body of link (35). 9. Mechanism according to any one of the preceding claims, wherein the connecting member (35) is formed in one piece, sheet metal cut and folded. 10. Mechanism according to any one of the preceding claims, wherein the two housing parts (18, 19) further comprise respectively two lateral flanges (21) substantially perpendicular to the end flanges (20) and arranged on both sides. other of a worm wheel (16), the worm wheel being rotatably mounted on the side flanges and meshing with an external toothing (15) belonging to the nut (14) to control a rotation of said nut . 11. Mechanism according to any one of the preceding claims, wherein the nut (14) is rotatably mounted on the end flanges (20) and said end flanges are applied by the connecting member (35). abutment against two opposite end faces (14a) belonging to the nut. A slideway having a first slide member (6) slidably mounted relative to a second slide member (7) in said longitudinal direction (X), said slideway having an adjustment mechanism according to any one of the preceding claims, the casing (17) is fixed to the first slide element (6) and whose screw (13) is secured to the second slide element (7). 13. Slide according to claim 12, wherein the housing (17) is mounted in a support (46) integral with the first slide member (6), said support (46) having two flaps (49) flanking the housing (17). in the longitudinal direction (X). 14. Vehicle seat comprising a seat (3) carried by at least one slide (5) according to claim 12 or claim 13.