FR2735997A1 - LONGITUDINAL ADJUSTING DEVICE FOR A VEHICLE SEAT COMPRISING LONGITUDINAL GUIDANCE - Google Patents

Abstract

Longitudinal adjustment device for a vehicle seat, comprising a longitudinal guide consisting of two rails movable one against the other, one of which is connected to a rack which has fixing zones for this junction, and of which the another houses an element, such as an endless screw or a pinion, which is driven by rotation and acts in concert with this rack. The rack including its fixing areas is manufactured in one piece by forming a blank (20) in a mold (22) with tools movable against each other (26) whose direction of movement is in the direction of the teeth of the finished rack.

Description

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  LONGITUDINAL ADJUSTING DEVICE FOR A SEAT OF

  VEHICLE. COMPRISING LONGITUDINAL GUIDANCE.

  The present invention relates to a longitudinal adjustment device for a vehicle seat, comprising a longitudinal guide consisting of two rails movable against each other, one of which is connected to a rack which has attachment zones for this junction, and the other houses an element, such as a worm or a pinion, which is driven

  by rotation and acts in concert with this rack.

  In the case of this longitudinal adjustment device of the kind

  mentioned at the beginning and known from the patent specification EP 195 123, the

  rack is, in practical embodiment as for example in the case of BMW E36 model, manufactured from two individual racks at least, typically three individual racks. The individual racks are arranged in layers next to one another transversely to the longitudinal direction of the rack and transversely to the direction of the teeth, they are connected to each other by means of rivets. Typically, each of the individual racks has a thickness of 3-4 mm and is manufactured by a shaping process, such as by stamping, sawing or the like, in which the machining direction is at right angles to a tense plane of teeth direction and direction

longitudinal rack.

  In principle, such racks have proven themselves. However, it is disadvantageous that they must be constructed of several spare parts, thus individual racks and additional junction and fixing means. Beyond this fact, it requires fixing areas o attack the fastening means for connecting the rack to the associated seat rail of the longitudinal guide. In the case of the longitudinal adjustment device of the type mentioned at the beginning, such fixing areas must be made as additional parts

separated.

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  This is exactly where the present invention comes into play. Its object is to develop a longitudinal adjustment device of the kind mentioned at the beginning so that, in particular, the rack can be manufactured with reduced expense and thus low costs, and that it is simpler in terms of construction, the additional benefits to be expected in terms of cooperation with the rotational component and the

strength of the rack.

  From the longitudinal adjustment device of the type mentioned at the beginning, this object is achieved by a longitudinal adjustment device 1o characterized in that the rack including its attachment areas is manufactured in one piece by forming a blank in a mold with movable tools against each other whose direction of movement is

  in the direction of the teeth of the finished rack.

  Advantageously, the rack has a width of at least 5 mm, preferably at least 7 mm; the attachment areas extend in the opposite direction to the teeth and at least two attachment areas are provided; the attachment areas extend in the longitudinal direction of the rack and an attachment area is disposed at at least one end of the rack; the tooth tips of the teeth of the rack are on lines which extend at an angle other than 90 relative to the longitudinal direction of the tooth axis, in particular at an angle less than 85; the tooth tips at the free ends of the teeth of the rack are respectively on an arc, in particular on an arc of a circle; the tooth tips are respectively on a circular arc and the contour diameter in the form of an arc of the tooth tips is adapted to the diameter of the worm; at least one attachment zone has a fixing hole which extends in parallel

to the direction of the teeth.

  The rack according to the invention is no longer manufactured from a sheet by machining this sheet transversely to its main surfaces, but it uses a blank which is placed in a mold in which it is machined by means of the tool belonging to the mold, the machining direction being carried out in the direction of the teeth of the finished rack, thus extending

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  rectangular in the machining direction during the manufacture of the rack according to the invention. The great advantage of this manufacturing method according to the invention and of the corresponding rack lies in the fact that the rack typically having a width of more than 5 mm, in most cases of more than 7 mm, can be manufactured. in one piece, the layered arrangement of at least two individual racks which, according to the prior art, was necessary until now is removed. During the manufacture of the rack according to the invention, it is in particular the area where the teeth are located which is formed. In doing so, a desired hardening in the area of the teeth is achieved, such as hardening. Therefore, the flanks of the teeth as well as the material of the teeth which is there behind are made so as to have a greater hardness than in the case of

the prior art.

  According to the invention, the fixing zones and the rack are manufactured in one piece, and it is thus no longer necessary to manufacture separate fixing zones and to connect them to the rack. The attachment zones can be provided at any point of the rack to

  the outside of the teeth, especially on the lower surface of the rack.

  which is in front of the teeth, and / or at the end zones. In this case, the fastening zones themselves can be made in such a way as to avoid subsequent machining, in particular the manufacture of a fastening hole or the like in the case of at least one fixing zone, preferably in the case of all areas. Preferably, the attachment zones according to the invention

  have fixing holes extending in the machining direction.

  The forming of the blank made to finally obtain the finished rack consisting of a single piece is essentially by stamping. As for that, reference is made to Dubbel, paperback for mechanical engineering, 14th edition, page 960 and following as well as the DIN 8583 mentioned therein. For the invention, it is in particular a mastering that comes into play. The blank may have the ambient temperature, but it is also possible to preheat it to a starting temperature which is higher than the ambient temperature. As for the manufacture, it is beyond this fact spinning, in particular extrusion, as well as cutting processes, precision cutting or pressure molding processes or injection molding which

come into play.

  According to the invention, the rack is no longer made of dishes, but from a blank consisting of a single piece, and preferably,

  a blank respectively used to make a single rack.

  The blank may be a bar having any shape of section, such as round and angular. The method according to the invention can be carried out in such a way that the bar is regular, so that it has a constant section over its entire length. In this case, the attachment zones must be formed and constructed correspondingly to make possible such a manufacture from an easily formed blank,

  this is possible within the scope of the invention.

  The material used for the rack, which comes into play is steel, AITiMg, a composite material reinforced with fibers

or a combination thereof.

  A particular advantage of the rack manufactured according to the invention lies in the fact that one is relatively free with regard to the formation of the teeth, and that, in particular, it is possible in any way to realize the contour of the edges of the teeth. at the free point of the teeth, for example along a curved line, at an angle to the longitudinal axis of the rack, and doing so in both possible directions, therefore as helical toothing and / or as cuneiform toothing. In the case of a curved contour of the tooth tip line, adaptation to a driving element made as a worm is more easily possible than in the prior art. In the case of a helical cut, it is possible to achieve a higher permissible load and a higher circumferential speed, it also results in greater stability of operation than in the case of the art.

prior.

  Other advantages and features of the present invention

  will appear on reading the following description of embodiments of

  the invention taken as non-limiting examples, which will be described in more detail in relation to the appended figures, in which: FIG. 1 is a perspective and sectional representation of a matrix intended for the manufacture of a rack according to the invention, - Figure 2 shows a cross section through a rack made according to the invention with teeth arranged on a curved line, - Figure 3 is a perspective representation of an end zone of 4 is a plan view of a section of the rack having a helical cut, and

  rack according to the invention having attachment zones.

  For the manufacture of the rack according to the invention, a blank 20 is placed in a mold 22, as shown in FIG. 1. In the case of the greatly simplified representation of the figure, the mold 22 is composed of only two parts, namely a mold bed 24 and a moving tool 26 which is moved according to the arrows 28 and pressed into a mold cavity mold lite 26. The lower surface of the tool 26 has a toothing which corresponds to the teeth that must be present in the coming rack. In the case of the embodiment shown, the mold bed is substantially flat bottom, it has a recess 30, in this recess flows the material of the blank 20, a fixing zone 42 is

done in this way.

  In the figure, the blank 20 is shown only schematically, as for the practical embodiment, it is in particular blanks having for example a rather rectangular sectional shape, which lend themselves to it, therefore a sectional shape. which is closer to that of the

cogwheel coming.

  Figure 2 shows a sectional view through a rack 32 manufactured according to the invention. One can see a tooth 34. It has a line of tooth tip 36 which follows the outline of an arc. Similarly, the bottom line of tooth 38 follows the outline of a line in a circular arc concentric to that. The

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  rack 32 according to Figure 2 is engaged with a rotatably driven member 40 formed as a worm. The axis of rotation of this screw without

  end extends parallel to the longitudinal direction of the rack.

  Another orientation such that an angle> 0 between the longitudinal directions and the directions of the axis of the worm is possible. The teeth 34 may also be arranged at an angle different from 90 relative to the longitudinal direction of the rack, as will be described later in relation to

with Figure 4.

  The rack 32 according to Figure 2 has a fixing zone 1o 42 projecting downwards, it passes through a hole 44 located in a bottom rail 46. The latter is associated with a seat rail 48. The two rails 46, 48 cooperate with each other in a manner known per se and are supported against each other by means of guiding means (not shown). They form an interior of canal in which is the arrangement constituted of

  the rack 32 and the rotational member 40.

  The worm 40 is mounted on the seat rail 48 rotatably and is rotated through a suitable drive (not shown). On the seat rail 48 is disposed a stop

  49 which follows the contour of the worm 40 and has a distance from it

  which is smaller than the measurement of the meshing between the worm 40 and the rack 32. Beyond this fact, the unit consisting of the worm 40 and the rack 32 is embraced in one piece socket 51 closed annularly, and for this purpose, the rack is made as shown on

Figures 3 or 5.

  Figure 3 is a perspective view of a rack, similar to the representation according to Figure 2, but the attachment zone 42 is made in a different way, it does not pass through a hole. It is also arranged at the end of the rack 32, is shifted downwards so that the actual rack 32 is a few millimeters higher and can be kissed from an annular closed part which is connected to the rotary drive element 40, such as a pinion. As shown in Figure 3, the rack 32 itself

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  forms a vat with narrow side faces, the vat extends over a body

  of cylinder, teeth 34 project upwards from this tank.

  FIG. 4 represents a plan view on a rack 32, the teeth 34 thereof extend at an angle of 60, for example, with respect to the longitudinal direction of the rack 32. Finally, FIG. 5 represents a rack and pinion complete, including two attachment zones 42 at the ends. The attachment zone 42 on the right in the figure is made in a manner similar to that of FIG. 3. The opposite attachment zone 42 at the other end is made as a block. It is introduced into a reception room which is connected to the bottom rail. Preferably, an elastic means such as a soft plastic cap is disposed between the receiving piece and the block-shaped attachment area. Due to this fact, we achieve an elastic prestress of the rack in the direction of its teeth, so the rack is

  prestressed elastically upwards.

  It is possible to provide a multitude of tenon-shaped attachment areas on the surface of the rack, which is in front of the teeth. These can mesh in corresponding recesses of the bottom rail. In this way, it is possible that the rack 32 is well anchored in the bottom rail so that the bottom rail also contributes to the stability. Figure 2 shows in addition the section width of the rack 32, which is designated d and between 7 and 8 mm. According to the invention, it can be chosen relatively large, it can be 10 mm per

example.

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Claims (7)

CLAIMS.   1 - Longitudinal adjustment device for a vehicle seat, comprising a longitudinal guide consisting of two rails movable against each other (46, 48), one of which is connected to a rack (32) which has zones fastener (42) for this junction, the other housing an element (40), such as a worm or a pinion, which is rotated and acts in concert with this rack (32), characterized by the rack (32) including its attachment zones (42) is manufactured in one piece by forming a blank (20) in a mold (22) with tools movable against each other ( 26) whose direction of travel is in the direction of   teeth (34) of the rack (32) finished.   2 - longitudinal adjustment device according to claim 1, characterized in that the rack (32) has a width of 5 mm at   less, preferably at least 7 mm.   3 - longitudinal adjustment device according to claim 1, characterized in that the attachment zones (42) extend in the direction   opposed to the teeth (34) and at least two attachment regions (42) are provided.   4 - longitudinal adjustment device according to claim 1, characterized in that the attachment areas (42) extend in the longitudinal direction of the rack (32) and a fixing area (42) is arranged to   at least one end of the rack (32).   - Longitudinal adjustment device according to claim 1, characterized in that the tooth tips of the teeth (34) of the rack (32) are on lines which extend at an angle different from 90 relative to the direction longitudinal axis of the tooth axis, particularly at an angle less than 85.   6 - longitudinal adjustment device according to claim 1, characterized in that the tooth tips at the free ends of the teeth (34) of the rack (32) are respectively on an arc, in particular on a circular arc.   7 - longitudinal adjustment device according to claim 6 comprising a rotatably driven member (40) and formed as a worm, characterized in that the tooth tips are respectively on a circular arc and the diameter of the contour in the form of a circular arc of   tooth tips is adapted to the diameter of the worm.   8 - longitudinal adjustment device according to claim 1, characterized in that a fastening zone (42) at least has a fixing hole which extends parallel to the direction of the teeth (34).