Manufacturing process for an adjustment mechanism of a vehicle seat

Abstract

Manufacturing process for an adjustment mechanism (6) of a vehicle seat (1), comprising the following steps: a) Providing an arrangement (60), comprising: - first and second fittings (7, 8) adapted to be mounted rotatably relative to each other about an axis (Y1), wherein the first and second fittings (7, 8) comprise inner surfaces (71, 81) which are oriented towards each other and inwards, outer surfaces (72, 82) which are oriented outwards in the opposite direction to each other, and circular circumferential edges (73, 83) offset from the axis (Y1), and - an annular sleeve (9) comprising a cylindrical base (91) covering the circumferential edges (73, 83) of the fittings (7, 8), and a first side tab (92) covering at least part of the outer surface (72) of the first fitting (7), b) Forming a second side tab (93) by bending a section of the annular sleeve (9) towards the outer surface (82) of the second fitting (8), and coming into contact with the outer surface (72) of the first fitting (7), and in which the following step is carried out between steps a) and b): - Positioning of the annular sleeve (9) with respect to the first fitting (7) with a defined clearance with a first tool (111), comprising first and second surfaces (113, 114), wherein the first surface (113) is suitable for coming into contact with the first side tab (92), and wherein the second surface (114) is suitable for coming into contact with the outer surface (72) of the first fitting (7), and wherein these surfaces (113, 114) are spaced apart from each other in the direction of the axis (Y1) to ensure the defined clearance between an inner surface of the first side tab (92) and the outer surface (72) of the first fitting (7), wherein the sleeve (9) is pressed towards the first tool (111), and the first tool (111) is pressed towards the first fitting (7) so that the surfaces (113, 114) can come into contact.

Description

[0001] The present invention relates to a manufacturing method for an adjustment mechanism of a vehicle seat,

[0002] Document FR 2 915 436 A1 describes an example of an adjustment mechanism of this type that operates satisfactorily and in which the sleeve further comprises a stop that bears against the inner surface of the second fitting. This allows the second tab to be formed by crimping between the inner and outer surfaces of the second fitting. Due to this stop of the sleeve and the crimping manufacturing process, the first fitting is not pinched by crimping the first tab of the sleeve, which prevents rotation of the first fitting relative to the second fitting. Operating clearances are maintained between the first fitting and the sleeve, as well as between the second fitting and the first fitting, allowing rotation.

[0003] US 2003 / 0 080 599 A1 discloses an adjustment device for the rotational adjustment of two centrally arranged adapter pieces, in particular for a seat, preferably for a motor vehicle seat. The adjustment device comprises a planetary gear with a sun gear and planetary gears. The planetary gear has a first housing part and a second housing part, each with an internal toothing. The housing parts are rotatable relative to one another and are held captively together. Both housing parts have an edge flange. A separate retaining ring, which engages over the edge flanges, holds the housing parts together. This enables simple and cost-effective assembly of the adjustment device and ensures its functionality even under high loads.

[0004] JP 2004-28181 A discloses a locking pawl of a reclining mechanism. The locking pawl has a carbon content of 0.20-0.3% on the surface and 0.20-0.33% in the interior.

[0005] US 8 162 400 B2 discloses a connecting device for rotatably connecting first and second object elements of a vehicle seat relative to each other. The connecting device comprises first and second connecting elements and a holding element. The first and second connecting elements are integrated in a direction of their mating disks so that they can rotate relative to each other. The first connecting element is integrally connected to the first object element. The second connecting element is integrally connected to the second object element. The holding element spans the outer peripheral surfaces of the first and second connecting elements to hold the connecting elements in a panel thickness direction. The holding element is provided with an opening portion. The first connecting element is provided with a protruding portion.The protruding portion extends in the radial direction through the opening portion and the protruding portion is fixed to the first object member.

[0006] US 7 314 250 B1 discloses a first fitting and a second fitting. The first fitting and the second fitting are driven via a common drive shaft. Each of the fittings has a first fitting part and a second fitting part, which are connected to one another via a gear, so that a rolling movement of the second fitting part on the first fitting part is possible, wherein the rolling movement changes an angle defined between the fitting parts. Each of the fittings has a driver which is rotatably mounted in its first fitting part and drives an eccentric which is arranged such that a rotation of the driver causes the rolling movement of the second fitting part on the first fitting part when the driver is driven by the drive shaft. To limit the angle between the fitting parts, a stopper is mounted on the first fitting.The driver of the first fitting is made of a material with high mechanical strength and the driver of the second fitting is made of a material with lower mechanical strength.

[0007] The present invention aims to propose an alternative to the assembly of first and second fittings which must be rotatable with respect to each other.

[0008] The object is achieved by a manufacturing method for an adjustment mechanism of a vehicle seat having the features of claim 1.

[0009] In other words, the invention achieves this by means of a manufacturing method having the features of the main claim. Preferred embodiments are listed in the dependent claims.

[0010] In various embodiments of the manufacturing method of an adjusting mechanism according to the present invention, one and / or more of the following features may be used if necessary.

[0011] According to one aspect of the invention, the sleeve is pressed radially inwardly onto, ie, radially towards the interior over, the peripheral edge of the second fitting.

[0012] According to one aspect of the invention, step b) is carried out with at least the following two sub-steps: b1) chamfering the cut of the sleeve at a first angle to form a collar inclined by the first angle, and b2) Folding the collar to a second angle of substantially 90° to form the second side flap opposite the outer surface of the second fitting, the assembly being pressed against a die into contact with a first tool in contact with the outer surface of the first fitting. In other words, the two sub-steps are: b1) bending the portion of the sleeve according to a first angle to create a collar which is angled about the first angle, and b2) bending the collar until a second angle of substantially 90° is reached to form the second side flap opposite the outer surface of the second fitting, the assembly being pressed against a die using a first tool, coming into abutment against the outer surface of the first fitting.

[0013] According to one aspect of the invention, the first angle is between 30° and 60°. In other words, the first angle is between 30° and 60°. Preferably, the first angle is equal to 45°.

[0014] Further features and advantages of the invention will become apparent from the following description of one of its embodiments, which is given by way of example and not as a limitation of the claimed method, in conjunction with the accompanying drawings.

[0015] In the drawing are: - Fig. 1 is a schematic view of a vehicle seat equipped with an adjustment mechanism according to an embodiment of the invention; - Fig. 2 is an axial sectional view of a prior art adjustment mechanism; - Fig. 3 is an axial sectional view of an adjusting mechanism according to the invention; - Fig. 4 is an axial sectional view of an enlarged portion of the Fig. 3; - Fig. 5 a perspective exploded view of the adjustment mechanism of the Fig. 3; - Fig. 5a is an enlarged view of a portion of the circumference of the exploded view of the Fig. 5 shown second fitting; and - Fig. 6a to 6h are views showing successive stages of an embodiment of the manufacturing process for producing the adjustment mechanism according to the invention shown in Fig. 3 to produce.

[0016] In the different figures, the same reference symbols are assigned to identical or similar elements.

[0017] Fig. 1 shows a front seat or vehicle seat 1 of an automobile or vehicle, which comprises a backrest 2 pivotally mounted about an axis Y1 on a seat base 3, the seat base 3 itself being mounted on a floor panel 4 of the vehicle, with the exemplary interposition of sliding rails 5.

[0018] Consequently, the inclination of the backrest 2 is adjustable by means of an adjusting wheel 6a or a similar component which drives a transmission adjustment mechanism 6 (a mechanism allowing the adjustment of the inclination of the backrest 2).

[0019] This adjustment mechanism 6 includes (see Fig. 2 of the state of the art and Fig. 3 according to the invention): - a first fitting 7, formed by a first metal flange extending in a plane perpendicular to the axis Y1, and which, in the example shown, is fixed to the frame of the backrest 2, - a second fitting 8 formed by a second metal flange extending parallel to the first fitting 7, the second fitting 8 being fixed to the frame of the seat 3 and the first fitting 7 being rotatably mounted with respect to the second fitting 8, and - engagement elements that couple the first fitting 7 to the second fitting 8 to adjust the angular position between the fittings (inclination of the backrest 2), and - At least one drive element, such as the adjusting wheel 6a, for controlling the adjustment of the angular position.

[0020] The first and second fittings 7, 8 are held next to each other on the outer circumference of the adjusting mechanism 6 by means of a sleeve 9.

[0021] The first and second fittings 7, 8 and the sleeve 9 form a closed housing that separates an interior and an exterior space. The engagement elements are arranged in the interior or inside. The backrest 2 and the seat surface 3 are arranged in the exterior or outside. The elements of the adjustment mechanism 6 are advantageously defined using these common definitions of interior and exterior or inside and outside with respect to the closed arrangement of the adjustment mechanism 6.

[0022] The first and second fittings 7, 8 each comprise: - inner surfaces 71, 81 which are oriented inwards of the adjusting mechanism 6, that is to say facing each other and in proximity to each other in order to come into contact with each other, at least on a peripheral portion of the adjusting mechanism 6, - outer surfaces 72, 82 oriented outwards with respect to the adjustment mechanism 6, that is to say opposite to each other, and -circular peripheral edges 73, 83, located at the radial end of the fittings 7, 8 and spaced from the axis Y1.

[0023] The sleeve 9 is annular in the shape of essentially a U, the opening of which is oriented inwards (towards the axis Y1).

[0024] According to the embodiment known from the prior art, shown in Fig. 2, which is taken from the previously cited document FR 2 915 436 A1, the peripheral edge 83 of the second fitting 8 has a larger diameter than the diameter of the peripheral edge 73 of the first fitting 7. The second fitting 8 further comprises an extension 85 in a radial direction perpendicular to the axis Y1, which forms a portion on which the sleeve 9 is press-fitted on each of its surfaces: the outer surface 82 and the inner surface 81.

[0025] Sleeve 9 also includes: - a cylindrical base 91 which covers or surrounds the peripheral edge 83 of the second fitting 8, - a first side flap 92 which at least partially covers a peripheral portion of the inner surface 81 of the second fitting 8 and a peripheral portion of the outer surface 72 of the first fitting 7, and - a second side flap 93 which covers a portion of the outer surface 82 of the second fitting 8.

[0026] The first side tab 92 has a substantially S-shape, which forms a stop, in contact against the inner surface 81 of the second fitting 8.

[0027] This first side flap 92 comprises, starting from the base 91, a first portion 92a which covers a portion of the inner surface 81 of the second fitting 8, a bend 92b, a second portion 92c which extends substantially parallel to the axis Y1 at a distance from the inner surface 81, and a third portion 92d which extends transversely to the axis Y1 from an extremity of the second portion 92c, laterally towards the outer surface 72 of the first fitting 7.

[0028] Due to this shape, the first side tab 92 and the second side tab 93 enclose the sleeve 9 via the extension 85 of the second fitting 8. The sleeve 9 is connected to the second fitting 8, and the second and third sections 92c, 92d of the first side tab 92 are shaped to maintain at least some play in the direction of the axis Y1, so that the first fitting 7 is rotatable with respect to the second fitting 8.

[0029] According to one aspect of the Fig. 3 to 5, the sleeve 9 comprises: - a cylindrical base 91, which covers or encloses the two peripheral edges 73, 83, - a first side flap 92 which at least partially covers a peripheral portion of the outer surface 72 of the first fitting 7 without covering the portion of the inner surface 81 of the second fitting 8, the inner surface 81 being opposite the inner surface 71 of the first fitting 7, and - a second side flap 93 covering a portion of the outer surface 82 of the second fitting 8.

[0030] The base 91 extends substantially in the direction of the axis Y1 directly between the first side flap 92 and the second side flap 93. The sleeve 9 therefore encloses the first and second fittings 7, 8 of the adjustment mechanism 6.

[0031] The sleeve 9 of the invention thus differs from the sleeve according to the prior art by its first side flap 92, which does not touch or contact any of the inner surfaces 71, 81 of the fittings 7, 8. In particular, the sleeve 9 has no touch or contact with the inner surface 81 of the second fitting 8. In other words, the sleeve 9 does not bear against any of the inner surfaces 71, 81. For example, it does not bear against a portion of the inner surface 81 of the second fitting 8.

[0032] The sleeve 9 is therefore an annular part with respect to the Y1 axis, having a cross-sectional shape in the shape of a capital C with its opening facing the Y1 axis. The base 91, which extends in the direction of the Y1 axis, corresponds to the vertical arm of the C-shape. The first and second side tabs 92, 93 correspond to the horizontal arms of the C-shape.

[0033] The first and second side tabs 92, 93 are formed by bending or deep-drawing a blank of the sleeve 9 toward the first and second fittings 7, 8. A first bend or deformation deforms the blank to form the first side tab 92 toward the first fitting 7. A second bend or deformation deforms the blank resulting from the previous step to form the second side tab 93 toward the second fitting 8, this second bend being performed without enclosing the fittings 7, 8 against one another and thus without securing them relative to one another.

[0034] An axial play in the direction of the axis Y1 is maintained so that the first fitting 7 is rotatable with respect to the second fitting 8, in particular due to the manufacturing process of the sleeve 9, which will be given in more detail further down in this description.

[0035] Due to the axial clearance, the sleeve 9 freely encloses the fittings 7, 8 without pressing or fastening them together. The fittings 7, 8 remain rotatable relative to each other around the axis Y1.

[0036] The sleeve 9 is, for example, in contact with a peripheral edge 83 of the second fitting 8. It is advantageously press-fitted with this peripheral edge 83. Consequently, the sleeve 9 is connected to the second fitting 8.

[0037] The sleeve 9 includes an inner surface at the base 91, which is slightly conical to define the peripheral edge 83 of the second fitting 8 and to expose the peripheral edge 73 of the first fitting 7. In particular, the inner surface of the sleeve tapers toward the axis Y1 as it extends from the first fitting 7 toward the second fitting 8. The sleeve 9 is thus connected to the second fitting 8, while maintaining a radial clearance with the first fitting 7, so that the first fitting 7 is rotatable.

[0038] The inner surface of the base 91, in conical shape, forms, for example, an angle less than 5° with the direction of the axis Y1, and more preferably an angle less than 1°.

[0039] The peripheral edge 83 of the second armature 8 may include teeth 86 projecting from the diameter of the peripheral edge 83. These teeth have, for example, a small height, for example, less than 0.5 mm and more preferably a height less than 0.2 mm. These teeth 86 may be arranged around the entire circumference, or in angular sectors around the axis Y1, as shown in Fig. 5a. These teeth 86 can have different shapes, including teeth with a triangular cross-section, a trapezoidal cross-section, a sine wave cross-section, and a wave with circular segments. The teeth 86 engage with the sleeve 9 when the sleeve 9 is mounted on the second fitting 8. The sleeve 9 is thus better connected to the second fitting 8.

[0040] The second fitting 8 advantageously has a diameter greater than or equal to the diameter of the first fitting 7. The first fitting 7 therefore has a radial clearance with the inner surface of the base 91 of the sleeve 9 and thus the first fitting 7 is rotatable with respect to the sleeve 9 and the second fitting 8.

[0041] The difference between the diameter of the first fitting 7 and the diameter of the second fitting 8 is, for example, less than 1 mm. Thus, the extension 85 of the prior art no longer exists. Its radial installation space is thus superfluous. Thus, the overall outer diameter of the adjustment mechanism 6 is smaller than that of the prior art.

[0042] The second fitting 8 advantageously has a diameter equal to the diameter of the first fitting 7. This eliminates the prior art extension 85. The overall outer diameter of the adjustment mechanism 6 is therefore smaller. The radial installation space is thus further reduced.

[0043] Finally, the first side plate 92 includes bulges 95 formed by local deformation in the direction of the Y1 axis. Local deformation is understood, for example, to be a hemispherical bulge. The axial functional play in the direction of the Y1 axis, which is necessary for the rotation of the first fitting 7 with respect to the second fitting 8, can thus be reduced. The bulges 95 are greater than or equal to three in number and are advantageously distributed at equal intervals over the circumference of the first side plate 92.

[0044] The adjustment mechanism 6 is manufactured according to the manufacturing process defined below, which is described in the Fig. 6a to 6h.

[0045] According to a first step, an arrangement 60 is provided which comprises: - first and second fittings 7, 8, adapted to be mounted rotatably relative to one another around an axis Y1, the fittings 7, 8 comprising inner surfaces 71, 81 oriented towards one another and inwards in the direction of the axis Y1, outer surfaces 72, 82 oriented opposite one another and outwards, and comprising in a direction perpendicular to the axis Y1 circular peripheral edges 73, 83, spaced from the axis Y1, and - an annular sleeve 9 comprising a cylindrical base 91 covering the peripheral edges 73, 83 of the fittings 7, 8 and a first side flap 92 substantially perpendicular to the base covering at least a portion of the outer surface 72 of the first fitting 7.

[0046] In particular, in the arrangement 60, the second side flap or flap 93 of the sleeve 9 is not yet formed. It comprises material in the axial extension of the base 91 and opposite to the first side flap or flap 92 in order to form the second side flap 93 around the axis Y1 by deep drawing or forming.

[0047] All known means and all known methods are suitable for producing the preformed first and second fittings 7, 8 and the sleeve 9. These components can also be formed, in particular, by deep drawing.

[0048] According to a second step, shown in Fig. 6a, the assembly 60 is mounted in an assembly press 100, which comprises: - a pressing die or die 101 comprising a first bore 102, - a first lower tool 110 (punch holder) and a first upper tool 111 (punch) which are suitable for moving relative to one another in the first bore 102.

[0049] The assembly 60 is positioned above the first lower tool 110 by, for example, simple stacking from bottom to top: the second fitting 8, the first fitting 7 and the sleeve 9 with its first side flap 92 extending above the first fitting 7.

[0050] The first bore 102 comprises, for example, three coaxial cylindrical sections with respect to the Y1 axis. The first section 102a, opening with respect to an upper surface of the die 101, has a first diameter slightly larger than an outer diameter of the sleeve 9 stacked on the assembly 60. A second intermediate section 102b has a second diameter slightly smaller than the aforementioned outer diameter of the sleeve 9. This second section 102b is arranged between the extension of the first section and below it, so that a first constriction 102d of the bore 102 between the first and second sections 102a, 102b reduces the diameter of the bore 102 from the first diameter to the second diameter. For the first and second diameters, the term "slight" is understood as having a diameter difference with the diameter of the sleeve 9 of less than 1 mm and preferably less than 0.2 mm.A third portion 102c has a third diameter smaller than the second diameter. It is located in the downward extension of and below the second portion 102b, so that a second constriction 102e further reduces the diameter of the bore 102 to transition from the second diameter to the third diameter. The third diameter, for example, substantially corresponds to an inner diameter of the first and / or second side tabs 92, 93 of the sleeve 9 when fully formed. The first and second constrictions 102d, 102e are, for example, conical in shape to progressively reduce the diameter of the bore 102.

[0051] The first lower tool 110 has a substantially cylindrical shape about a rotation axis coaxial with the Y1 axis. It has a diameter smaller than the third diameter of the bore 102 to allow movement in all sections 102a, 102b, 102c thereof. It includes an upper surface 112 on which the outer surface 82 of the second fitting 8 is arranged, this outer surface 82 thus being oriented downward.

[0052] The first upper tool 111 is substantially cylindrical in shape about an axis of rotation coaxial with the Y1 axis. It includes, on its periphery, an annular shoulder directed downwards toward the assembly 60 disposed on the first lower tool 110. This shoulder forms a stop defining a first annular outer surface 113 perpendicular to the Y1 axis and a second inner annular surface 114 perpendicular to the Y1 axis, the two surfaces 113, 114 being spaced apart from each other by a first distance along the Y1 axis.

[0053] According to a third, in the Fig. In the step illustrated in Figure 6b, the first upper tool 111 is lowered toward the assembly 60. The first surface 113 lies opposite the first side flap 92 of the sleeve 9, and the second surface 114 comes into contact with the first fitting 7 and bears downwardly against the first fitting 7. The first and second fittings 7, 8 are thus held against each other, with their inner surfaces 71, 81 in reciprocal contact, between the first upper tool 111 and the first lower tool 110.

[0054] The first distance between surfaces 113, 114 is slightly larger than the diameter of the sheet metal of the first tab 92. This first distance is equal to the thickness of the first tab 92 plus a functional clearance. The sleeve 9 can thus move upward under an upward force applied to the sleeve 9 until the first tab 92 comes into contact with the first surface 113. A functional clearance, including under the first tab 92, between it and the outer surface 72 of the first fitting 7, is thus formed.

[0055] According to a fourth, in Fig. In the step shown in Figure 6c, the first lower die 110 and the first upper die 111 move downward together to bring the axial extension of the base 91 into contact with the first constriction 102d of the first bore 102. The sleeve 9 is thus partially inserted into the first constriction 102d and, for example, at a portion thereof relative to the peripheral edge 83 of the second fitting 8. This first constriction 102d locally reduces the diameter of the sleeve 9 and radially surrounds it or fits it over the peripheral edge 83 of the second fitting 8 to join the two together. In this step, the die 101 exerts an upward force on the sleeve 9 by friction.The sleeve 9 therefore maintains the position described above during this step, i.e. a position in which the first side flap 92 is in contact with the first surface 113 of the first upper tool 111, which guarantees that the functional clearance between the first side flap 92 and the first fitting 7 is maintained.

[0056] This fourth step enables the connection by radial compression of the sleeve 9 with the second fitting 8 in a correct position of the sleeve 9 in order to maintain an axial functional play which allows the rotation of the first fitting 7 with respect to the second fitting 8.

[0057] This fourth step can be implemented in various ways, which can also be combined if necessary. Indeed, the second fitting 8 may include the teeth 86, or the sleeve 9 may have a substantially conical base 91, or an outer diameter of the outer edge of the second fitting 8 may be larger than an inner diameter of the base 91.

[0058] According to a fifth, in the Fig. In the step shown in Figure 6d, the first lower die 110 and the first upper die 111 continue to move downward together, forcing the axial extension of the base 91 to enter the second constriction 102e. The second constriction 102e has a conical shape that constricts or bends the axial extension of the base 91 to begin forming the second lateral flap 93. This second constriction 102e has a first angle with the axis Y1, for example, between 30° and 60°. Preferably, this is substantially equal to 45° plus or minus 1° or 2°. The second flap 93 is thus partially formed at an angle corresponding to the first angle. In this step, the die 101 continues to exert an upward force on the sleeve 9, guaranteeing the predetermined position. Furthermore, this fixed position cannot vary due to the radial compression of the fourth step.The bending is thus performed on the sleeve 9, which is located in the specified position along the Y1 axis. The functional clearance in the axial direction is thus guaranteed, and the axial extension of the sleeve 9 assumes an angled shape according to the first angle for the specified position of the sleeve 9.

[0059] The assembly 60 of the adjustment mechanism 6 is subsequently removed from the press 100 by moving upwards the first upper tool 111 and the first lower tool 110, in particular by exerting a first force F1 upwards on the first lower tool 110.

[0060] This fifth step allows the second side flap 93 to be partially bent to form it. Optionally, the method of the invention can omit this intermediate step to directly perform the complete bending as described in the subsequent steps.

[0061] According to a Fig. In the sixth step shown in Figure 6e, the assembly 60 of the adjustment mechanism 6 is moved to another location of the press 100. At this location, the pressing die 101 includes a second bore 104, which is different from the first bore 102, and the press 100 includes a second lower tool 120 and a second upper tool 121, which are adapted to move relative to one another in the second bore 104.

[0062] The second bore 104 is a simple cylindrical bore having a single inner diameter slightly larger than the outer diameter of the sleeve 9. The sleeve 9 and the assembly 60 can thus slide in this second bore 104. The assembly 60 is positioned in this second bore 104 on the second lower tool 120, with the second side flap 93 partially formed and angled according to the first angle, and is subsequently positioned on an annular surface 122 of the second lower tool 120. This annular surface 122 is substantially perpendicular to the Y1 axis.

[0063] The second upper tool 121 has a substantially identical shape to the first upper tool 111. It comprises an annular projection extending in the direction of the Y1 axis. This forms a stop defining a first outer annular surface 123, which is perpendicular to the Y1 axis, and a second inner annular surface 124, which is perpendicular to the Y1 axis. However, these two surfaces 123, 124 are spaced apart from each other by a second distance in the direction of the Y1 axis, which is greater than the first distance of the first upper tool 111. The first surface 123 can no longer come into contact with the first tab 92. Only the second surface 124 is suitable for coming into contact with the outer surface 72 of the first fitting 7 in order to press the first fitting 7 against the second fitting 8.

[0064] According to a seventh, in Fig. In the step shown in Figure 6f, the assembly 60 of the adjustment mechanism 6 is positioned over the second lower tool 120. Subsequently, the second upper tool 121 is lowered against the outer surface 72 of the first fitting 7 and exerts a downward force on the first fitting 7 to press the assembly 60 toward and against the second lower tool 120.

[0065] The annular surface 122 of the second lower tool 120 subsequently deforms the tab 93 bent according to the first angle until it assumes the shape of the second annular surface 122, that is, until the second tab 93 is substantially perpendicular to the axis Y1 and until it comes into contact with the outer surface 82 of the second fitting 8.

[0066] Since the second upper tool 121 is in contact with the outer surface 72 of the first fitting 7 and not with the first tab 92 of the sleeve 9, the functional play in the axial direction between the first tab 92 and the first fitting 7 is preserved or maintained during this step of bending by 90° the second side tab 93.

[0067] The assembly 60 is thus converted into an adjustment mechanism 6 with a sleeve 9 of simple form; that is, without a radial extension to support the casing of the sleeve 9, as is common in the prior art. Furthermore, the axial functional play is ensured by allowing the first fitting 7 to rotate relative to the second fitting 8.

[0068] This seventh step allows the overall bending of the second side flap 93.

[0069] The two steps, fifth step of partial bending and seventh step of total bending, allow a progressive forming of the second tab 93, with a precise position in the direction of the axis Y1, which guarantees an axial functional play for the rotation of the fittings 7, 8 with respect to each other.

[0070] According to an eighth, in the Fig. In the step shown in Figure 6g, the adjustment mechanism 6 is finally removed from the press 100, with the second upper tool 121 and the second lower tool 120 moving upwards, in particular with the application of a second force F2 directed upwards onto the second lower tool 120. Fig. 6h represents the adjustment mechanism 6, entirely taken from the second bore 104 of the press 100.

[0071] The bulges 95 of the first side flap 92 can be formed before or after the formation of the second side flap 93, as is done in the steps described above.

[0072] The steps mentioned are only one embodiment of the invention, for which variations are possible. The method according to the invention makes it possible to form a sleeve 9 more easily by means of the step or steps of the method that allow the second side flap 93 to be formed in contact with the outer surface 72 of the first fitting 7. The first distance of the first upper tool 111 allows an axial functional clearance to be maintained between the fittings 7, 8 and the side flaps 92, 93 of the sleeve 9.

[0073] Due to this process, the sleeve 9 no longer comprises a portion which is in contact with one of the inner surfaces 71, 81 of the fittings 7, 8.

[0074] The sleeve 9 is therefore simpler in shape, encloses the fittings 7, 8 and allows the rotation of the fittings 7, 8 with respect to each other.

Claims

[1] Manufacturing method for an adjustment mechanism (6) of a vehicle seat (1), comprising the following steps: a) providing an arrangement (60) comprising: - first and second fittings (7, 8) adapted to be mounted rotatably relative to each other about an axis (Y1), the first and second fittings (7, 8) comprising inner surfaces (71, 81) oriented towards each other and inwards, outer surfaces (72, 82) oriented outwards opposite each other, and circular peripheral edges (73, 83) offset from the axis (Y1), and - an annular sleeve (9) comprising a cylindrical base (91) covering the peripheral edges (73, 83) of the fittings (7, 8) and a first side flap (92) covering at least part of the outer surface (72) of the first fitting (7), b) forming a second side flap (93) by folding a cut of the annular sleeve (9) towards the outer surface (82) of the second fitting (8) and coming into contact with the outer surface (72) of the first fitting (7), and in which between steps a) and b) the following step is carried out: - positioning the annular sleeve (9) with respect to the first fitting (7) with a predetermined clearance using a first tool (111) comprising first and second surfaces (113, 114), the first surface (113) being adapted to bear against the first lateral tab (92) and the second surface (114) being adapted to bear against the outer surface (72) of the first fitting (7), and these surfaces (113, 114) being spaced apart from one another in the direction of the axis (Y1) in order to ensure the predetermined clearance between an inner surface of the first lateral tab (92) and the outer surface (72) of the first fitting (7), the sleeve (9) being pressed towards the first tool (111) and the first tool (111) being pressed towards the first fitting (7) so that the surfaces (113, 114) can bear against one another. [2] Manufacturing method according to claim 1, wherein the sleeve (9) is pressed radially towards the interior over the peripheral edge (83) of the second fitting (8). [3] Manufacturing process according to one of claims 1 or 2, wherein step b) is carried out in at least two sub-steps as follows: b1) bending the portion of the sleeve (9) according to a first angle to create a collar which is angled by the first angle, and b2) bending the collar until a second angle of substantially 90° is reached to form the second side flap (93) opposite the outer surface (82) of the second fitting (8), the assembly being pressed against a die (101) using a second tool (121) to bear against the outer surface (72) of the first fitting (7). [4] Manufacturing method according to claim 3, wherein the first angle is included between 30° and 60°, and preferably equal to 45°.

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