The invention relates to the field of motor vehicle equipment.
The present invention relates to a guide rail of a device for guiding a sliding window in a door of a motor vehicle, a device for manufacturing this rail by injection and the method for manufacturing this rail using this device for manufacturing.
A motor vehicle door comprises a caisson that is extended at its upper portion by a frame. This frame comprises two uprights, namely a front upright and a rear upright, connected together by a crosspiece. This frame delimits with the caisson, an opening. A window is mounted slidingly in the door in such a way as to close off or not this opening. At least one device for guiding is disposed either in the front upright, or in the rear upright to guide this window during the movement thereof.
Each device for guiding comprises a guide rail and at least one sliding guide shoe. The accompanying
It can be seen that the guide rail A has the form of a continuous hollow profile provided with a longitudinal slot B. The guide shoe C has an end D fastened onto the inner face of the window E and another end F received and guided in the channel of said guide rail.
This guide rail can be obtained by extrusion. However, although the known methods of extrusion make it possible to obtain guide rails with a C-shaped cross-section, the latter are necessarily straight or very slightly curved. However the invention has for purpose to produce any type of rails, including a rail that is more heavily arched.
The guide rail can also be obtained by injection moulding. However, in this case, as the channel of the guide rail does not have any draft angles, this rail cannot be unmoulded directly. The mould must therefore be adapted so as to have two drawers G and H, as shown in the accompanying
However, if it is sought to carry out a guide rail that is simultaneously arched and has a cross-section in the shape of a C, it is then no longer possible to proceed with unmoulding as explained hereinabove.
It is known according to the state of the art, the technique of injection with a projectile (known under the acronym “PIT” for “Projectile Injection Technique”), the technique of injection with water, (known under the acronym “WIT” for “Water Injection Technique”) and the technique of injection with gas, (known under the acronym “GIT” for “Gas Injection Technique”), which consist respectively in sending a projectile of calibration, water or gas, in the injected melted plastic material, to form hollow bodies. However, these methods do not make it possible to precisely control the shape of the inside hollow portion of this body, or its surface condition. Consequently, these methods are not adapted to the carrying out of a guide rail of which the function is indeed to guider a sliding guide shoe as precisely as possible.
Finally, regardless of the aforementioned method of obtaining used, the rail obtained must then be assembled with additional parts, such as support profiles or structural profiles, which cannot be obtained as a single piece with said rail.
It is known according to document DE 2331 785 a straight guide rail, inside of which is inserted a part made of plastic material manufactured by injection and that facilitates the sliding of the seat.
It is finally known according to document WO 2015/063576 a device for moulding a miniature portable pump, which makes it possible to manufacture the body of the pump. However, this body does not have a longitudinal groove.
The invention therefore has for purpose to overcome the aforementioned disadvantages of the prior art and to propose a straight or curved guide rail, provided with a slot over at least one portion of its length and obtained by injection, a device and a method for manufacturing via injection the aforementioned guide rail.
The invention also has for purpose to obtain, via an injection method, a guide rail such as mentioned hereinabove, that does not have any draft angles and of which the cross-section has a shape such that it does not allow for the simple unmoulding via extraction of the mould through the slot.
To this effect, the invention relates to a guide rail, in particular for guiding a guide shoe fastened to the sliding window of a motor vehicle door.
In accordance with the invention, this guide rail is made from an injected plastic material, and it comprises at least one portion having the shape of a tubular profile, which has a recess over its entire length and which is provided over at least one portion of its length with a longitudinal slot and this tubular profile is curved in the shape of an arc of a circle, this arc of a circle being inscribed in a plane, in such a way that the outer surface of said tubular profile has a concave longitudinal zone, an opposite convex longitudinal zone and two opposite lateral longitudinal zones, with each lateral longitudinal zone extending from the concave zone to the convex zone, and in that said longitudinal slot extends along one of the two lateral longitudinal zones or along the concave longitudinal zone.
Such a guide rail has the aforementioned desired characteristics.
According to other advantageous and non-limiting characteristics of the invention, taken alone or in combination:
The invention also relates to an injection moulding device of the aforementioned rail.
In accordance with the invention, this device comprises:
According to other advantageous and non-limiting characteristics of the invention, taken alone or in combination:
Finally, the invention also relates to a method of moulding the aforementioned guide rail.
In accordance with the invention, this method comprises the steps consisting in:
Other characteristics, purposes and advantages of the invention shall appear in the following description, which is purely for the purposes of information and is not limiting, and which must be read with respect to the accompanying drawings wherein:
In all of the figures, identical elements bear identical references.
The guide rail 1 in accordance with the invention comprises at least one portion having the shape of a tubular profile 10. A possible embodiment of this tubular profile is such as shown in
In this example, the profile 10 has over its entire length, a recess 11 of circular cross-section. Furthermore, the profile 10 is provided with a longitudinal slot 12 that extends over its entire length. The slot 12 opens both onto the outside of the rail and inside the recess 11. The tubular profile 10 therefore has a cross-section in the shape of a C.
The profile 10 can however have a section of another shape, for example a shape of an ellipse, a square shape or a rectangular shape.
It can also be closed off at one of its two ends.
Finally, the slot 12 may not extend over the entire length of the profile 10 and stop before one of the two ends of the latter, preferable at a short distance from this end (see for example the hatched portion 100 of the rail 10 wherein there is no slot 12).
Furthermore, regardless of its section, the profile 10 is preferably curved in the shape of an arc of a circle in such a way as to have over its entire length, a concave longitudinal zone 13, an opposite convex longitudinal zone 14, and two opposite lateral longitudinal zones 15 and 16, (also see
However, note that seen from above and as shown in
The profile 10 can also not be curved at all.
When the profile 10 is curved, the recess 11 of
When the tubular profile 10 is curved, the longitudinal slot 12 extends either along the concave longitudinal zone 13, or along one of the two lateral longitudinal zones 15 or 16, (here the zone 16 in figures), by then being disposed preferably at mid-distance or substantially at mid-distance between the convex longitudinal zone 14 and the concave longitudinal zone 13.
The tubular profile 10 has a radius of curvature R, preferably comprised between 300 mm and infinity, more preferably between 1000 mm and 2000 mm, in order to facilitate the unmoulding of the rail 1.
The tubular profile 10 has a central longitudinal axis X-X′ which is therefore either straight, or in the shape of an arc of a circle following the shape of the profile, this arc of a circle being inscribed in a plane P1.
The guide rail 1 allows for the guiding of a guide shoe P, such as for example the one shown in
As can be seen in
In its most basic form, the guide rail 1 in accordance with the invention comprises solely a tubular profile 10. However, it can also comprise at least one longitudinal wing 17 that extends from the outer surface of the profile 10 and which forms a single piece with this profile 10. The term “single piece” means that it is integrally formed with the profile 10.
The guide rail 1 in accordance with the invention can be carried out as a whole in a single injected material (that latter able to be composite). It can also be carried out in several injected materials, and in this case, these are different portions of the rail 1 which are carried out in different materials.
By way of a purely illustrative example, if there is a single material the latter can be chosen from polypropylene (PP), polyoxymethylene (POM), acrylonitrile butadiene styrene (ABS), acrylonitrile butadiene styrene/polycarbonate (ABS/PC).
When the rail comprises two different materials, the aforementioned materials can be combined, and even a thermoplastic vulcanizate (TPV) can be added chemically or mechanically compatible with one of the aforementioned materials.
Finally, if the rail comprises for example three materials, for example to carry out three different portions, it is possible for example other than all of the aforementioned materials add poly methyl methacrylate (PMMA), acrylonitrile styrene acrylate (ASA), or styrene acrylonitrile on a support made of acrylonitrile butadiene styrene (ABS) or acrylonitrile butadiene styrene/polycarbonate (ABS/PC).
The invention also relates to an injection moulding device 2 that makes it possible to manufacture the aforementioned rail 1 and which shall now be described in more detail in liaison with
Generally, the moulding device 2 in accordance with the invention comprises a mould 3, a device 5 for injecting under pressure plastic material inside said mould and a device 6 for extracting the male portion of this mould outside the female portion of the latter.
The mould 3 shall now be described in liaison with
The moulding cavity 4 comprises a portion 40, referred to as “moulding cell”, the shape of which corresponds to that of the curved tubular profile 10 of the guide rail.
In other terms, a minima, the moulding cavity 4 can comprise only the moulding cell 40, as shown in the example of
The male portion 31 of the mould is used to make the recess 11 of the rail 1, as well as the longitudinal slot 12.
The female portion 30 of the mould is used to manufacture the outer surface of the tubular profile 10 and the wings 17, as well as the tabs 18 when they exist.
In the embodiment shown in
The zone 300a has for example a cross-section in an arc of circle and a curved and concave shape over its entire length in such a way as to make the convex portion 14 of the profile 10 of the rail 1. Inversely, the zone 300b has a cross-section in an arc of circle and a curved and convex shape over its entire length, in such a way as to form the concave zone 13 of the rail 1. Note that when the profile 10 is straight, the zones 300a and 300b of the mould have a cross-section in an arc of a circle but are straight over their entire length.
The mould 3 could of course comprise more than two parts.
Thus, in the embodiment shown in
In this embodiment, it can be seen for example that the part 30f is a drawer that is mobile in translation in a direction perpendicular to the plane of the cross-section of the mould shown in
It is easily understood that the number of parts that form the female portion 30 of the mould 3 can be adapted according to the guide rail to be produced.
The male portion of the mould that makes it possible to obtain a rail provided with a curved profile 10 shall now be described.
Advantageously, and as can be seen in
The core 32 is curved in the shape of an arc of a circle, this arc of a circle being inscribed in a plane. In the embodiment shown in
Furthermore, as can be seen in the diagram of
The core 32 is curved in such a way that it has on its outer surface a convex longitudinal zone 321 (convex over its length), an opposite concave longitudinal zone 322 (concave over its length) and two lateral longitudinal zones 323, 324, with each one of them joining the convex zone 321 to the concave zone 322.
The core 32 is extended towards the outside either from its concave zone 322, or from one of its two lateral zones (here the zone 324) and over at least one portion of its length, by said intermediate part 33.
The cross-section of said intermediate part 33 has for example a shape of an arc of a circle of which the inner radius R2 corresponds to that of the circular cross-section of the core 32, and of which the outer radius R3 corresponds to that of the circle that delimits the moulding cell 40. In other terms, the thickness E1 of this intermediate portion 33 corresponds to the thickness E2 of the guide rail to be obtained (see
Furthermore, and over its entire length, and as appears better in
The male portion of the mould that makes it possible to obtain a rail provided with a straight profile 10 shall now be described. It differs from what has just been described in that the core 32 is straight and of a circular cross-section or not and in that the intermediate part 33, which protrudes along the core 32, is also straight.
A possible embodiment of the injection device under pressure 5 shall now be described in liaison with
Conventionally, the device 5 allows for the injection under pressure of plastic material inside the moulding cavity 4.
The injection device 5 comprises a body 50, supplied with plastic material M by a hopper 51. A worm screw 52 is disposed inside the body 50. It is driven in rotation by a motor (not shown in the figures), in such a way as to push the plastic material under pressure through an outlet orifice 53, itself connected to the moulding cavity 4.
The extraction device 6 makes it possible to displace the core 32 outside the moulding cell 40, from one of the two ends of the latter.
An embodiment of the extraction device 6 shall now be described in liaison with
The cooperation part 34 comprises a tab 340, curved along its length, in such a way that it has a shape of an arc of a circle, this circle being coaxial to the central axis Y1-Y′1 of the ring of which the core 32 constitutes a portion. This tab 340 has on its upper face a series of teeth 35 that together form a rack 350.
The extraction device 6 comprises a pinion 60 driven in rotation by a displacement device not shown in the figures. This displacement device can for example be a rotating cylinder or a geared motor.
The pinion 60 is disposed in such a way that its axis of rotation Y-Y′ is parallel to the axis Y1-Y′1 of the ring forming the core 32 of the male portion. The teeth 600 of this pinion 60 mesh with the teeth 35 of the rack 350.
The rotation of the pinion 60 drives the displacement of the rack 350 and therefore jointly that of the core 32. This displacement is carried out in a trajectory in the shape of an arc of a circle of the same radius as the radius R4 of the core 32, thus causing the extraction of the core 32 outside the moulding cell 40 of the mould. The rotation in the inverse direction of the pinion inversely makes it possible to bring back into position the core 32 inside the moulding cell 40. As can be seen in
Preferably, and as can be seen in
The extraction force exerted by the pinion 60 is exerted in a straight direction K tangent to the direction of bending X2-X′2 of the rack 350 and in the direction of the arrow F1. This extraction force compensates the unmoulding force that is exerted in a straight direction J tangent to the extraction trajectory in the shape of an arc of a circle X1-X1′, X1-X1′ being inscribed in the plane P1 and X1-X1′ also corresponding to the curved central longitudinal axis of the core 32. When the core 32 is in the profile 10, note that the arcs of circle X1-X′1 and X-X′ are confounded. The directions J and K are parallel.
When the core 32 is straight, the extraction device 6 differs in that the tab 34 as well as the rack 350 are straight and parallel to the core 32. Furthermore, the extraction is also carried out in a straight manner.
The method of moulding in accordance with the invention shall now be described. It comprises a first step that consists in injecting plastic material under pressure using the device 5 inside the cavity 4 of the mould 3 of the moulding device in accordance with the invention.
The following step consists in hardening this plastic material, for example by heating.
When the plastic material has hardened and the guide rail 1 is formed, the extraction device 6 is actuated in such a way that the displacement device drives the pinion 60 in rotation. This pinion meshes with the rack 350 and causes the displacement of the core 32 outside the cavity 40 and also outside the recess 11 of the profile 10 of the guide rail 1 (see arrow F1 in
When they are present, the retaining tabs 18 perpendicular to the wings 17 make it possible to retain the moulded rail 1 in the female portion 30 of the mould during the displacement of the male portion 31.
Advantageously, the different portions that form the female portion 30 of the mould are then separated in order to allow for the unmoulding of the guide rail 1.
Then, by driving the pinion 60 in rotation in the inverse direction, the core 32 can be brought back to the initial position inside the cavity 40 (arrow F2), for the moulding of another guide rail 1.
Number | Date | Country | Kind |
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FR1909216 | Aug 2019 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/071343 | 7/29/2020 | WO |