FR2994900A1 - SLIDING ASSEMBLY FOR A SEAT AND SEAT COMPRISING SUCH AN ASSEMBLY - Google Patents

Abstract

A vehicle seat slide assembly comprising two parallel rails (5) extending in a longitudinal direction (X) and each having a screw and nut adjusting mechanism (2), a cross member (1) extending mainly along a transverse direction (Y) interconnecting the two slides, characterized in that a piezoelectric motor (3) is integrated in the cross member and coupled to the adjusting mechanisms (2) by at least one transmission link.

Description

The present invention relates to sets of 5 slide rails for a seat, in particular for a vehicle seat; it also relates to seats comprising such sets of slides. More particularly, the invention relates to a set of slides for a vehicle seat, comprising: two parallel rails extending in a longitudinal direction and each comprising a screw and nut adjusting mechanism, at least one extending cross-member; mainly in a transverse direction, interconnecting the two slides, and supported at each of its two ends respectively by one of the two slides, the cross member supporting an electric motor with a rotor coupled to the adjustment mechanisms by at least one transmission link . DE 10 2007 027322 discloses an example of such a set of slides. In these known slide assemblies of this type, a brush DC motor is conventionally installed. However, this solution may cause some operating noise. In addition, this type of motor can generate electromagnetic noises, and it is difficult to control movements with stop and start ramps. It has appeared useful to further improve these slide assemblies, in particular to reduce the risk of operating noise and also to improve the reliability of the system. For this purpose, according to the invention, a set of slides of the kind in question is such that a single piezoelectric motor is arranged on the crossmember, said motor being coupled to the adjustment mechanisms by at least one transmission link. .

Thanks to these provisions, it can reduce the operating noise of the set of slides. In addition, a judicious choice of the characteristics of the electric motor makes it possible to obtain a greater flexibility of control and makes it possible to reduce the electromagnetic noises engendered by the operation of the motor. In embodiments of the slide assembly according to the invention, one and / or other of the following arrangements may be used in isolation or in combination. In one aspect, the cross member may include a housing housing of the piezoelectric electric motor, said motor including a stator directly received in the housing housing, and a rotor coupled to the control mechanisms of the transmission link. So that the mechanical integration is optimized and the cost and dimensions can be optimized. In another aspect, the rotor is rotatably mounted about a vertical axis perpendicular to the longitudinal and transverse directions, the assembly further comprising a bevel gear at the rotor shaft output; so that the integration is optimized and the space under the seat is limited. In another aspect, the nominal rotational speed of the rotor is 100 to 400 rpm and preferably in the vicinity of 200 rpm; so that such a low rotation speed can reduce some operating noise. According to another aspect, each of the adjustment mechanisms may comprise a second angular gear and an intermediate shaft parallel to the longitudinal direction X, the intermediate shaft being driven by the second angle gear and driving a captive rotating nut. In another aspect, the cross member may include a spar, an engine base and a cover, the cover closing the housing housing; which allows an assembly with motor protection in the housing. In another aspect, the motor base can be fixed to the spar by means of first elastic fastening clips; which facilitates assembly operations. In another aspect, the cover can be fixed to the motor base by means of second elastic fixing clips; which facilitates assembly operations. In another aspect, the slide assembly 10 may include an electronic card adapted to control the motor; so that the engine control means is close to the latter which is favorable from the electromagnetic point of view. In another aspect, the transmission link 15 may comprise on each side a rigid bar extending between the drive device and the adjustment mechanism; so that the transmission link can support the torque delivered by the engine. In another aspect, the transmission link 20 includes a first bar extending from one of the two adjustment mechanisms to the motor and a second bar extending from the motor to the other adjustment mechanism; so that assembly of the assembly is easy. In another aspect, the transmission link 25 may be a rigid bar extending from one adjusting mechanism to the other; so that the transmission link can be simplified. Furthermore, the invention also relates to a vehicle seat comprising a seat carried by a set of slides as defined above. Other features and advantages of the invention will emerge during the following description of two of its embodiments, given by way of non-limiting examples, with reference to the attached drawings. In the drawings: FIG. 1 is a perspective view of a set of slides for a seat, comprising two slides and a motorization device; FIG. 2 is a vertical longitudinal sectional view of the motorization device of the FIG. 1 is a perspective view of an exploded portion of a central portion of the motorization device of FIG. 1; FIG. perspective of a burst of a slide adjustment mechanism of the assembly of Figure 1, - Figure 5 is a partial bottom view of the drive device of Figure 1, removed cover. FIG. 1 shows a set of slides 100 for a motor vehicle seat which comprises a back supported by a seat. Said seat is itself slidably mounted by means of the set of slides on the floor of the vehicle in a longitudinal direction X 20 substantially horizontal. As shown in Figures 1 to 5, each of these two rails 5 (left and right) comprises a fixed section 7 fixed to the floor and a movable section 6 fixed to the seat. Each movable section 6 is slidably mounted in the longitudinal direction (respectively X1 and X2) in the fixed profile 7 by means of guide elements such as balls 67. In this case, the movement of the movable profiles 6 is motorized thanks to a motorization device extending between the two slides 5 and drive mechanisms 2 also called position adjustment mechanisms or adjustment mechanisms 2. A setting mechanism 2 is disposed in the left movable profile and another similar setting mechanism 2 is disposed in the straight movable profile. These are adjustment mechanisms of the "screw and nut" type: a captive rotating nut 9 is rotatably mounted on a longitudinal helical screw 90 fixed to the fixed profile 7. The screw 90 does not rotate, but the nut is imprisoned 9, turning on the helical screw, and following the helical path of the screw, causes the longitudinal displacement of the movable section 6. Regarding the adjustment mechanisms 2, further details will be given later. The two adjustment mechanisms 2 are controlled in a synchronized manner, so that the movable profiles 6 right and left move together; this distributes the forces in a balanced way between right and left and avoids an offset of a movable section 6 relative to the other. The motorization device comprises a cross-member 15 1 which extends mainly in a transverse direction Y. The cross-piece connects the two slides together, and the cross-member 1 is supported at each of its two ends respectively by one of the two slideways, in the form of a cross-member. by the movable sections 6 of each slide 5. The right end 61a of the crossbar is connected to the movable section 6 of the right slideway; said end is fixed on the movable section 6 by a holding bracket 21 which immobilizes it in the X and Z directions. Similarly, the left end 61b interfaces with the movable section 6 of the left-hand slide rail, to which it is fixed by a holding bracket 21 in an identical manner. More particularly, the cross member 1 is made of molded plastic, for example polyamide, polyethylene, polypropylene, or any other suitable plastic material. In this crosspiece are housed: a piezoelectric motor 3 which comprises a stator 36 and a rotor 35 with a rotor shaft 37 integral with the rotor 35, the axis of the rotor Z being perpendicular to the longitudinal X and transverse Y directions, otherwise said vertical axis, - a transmission link 50 extending transversely along Y, which transmits the rotational movement to the adjusting mechanisms 2 of the right and left slide rail, - a first angular gear 60,61 which transmits the rotor rotation 35 about the vertical axis Z to the Y-axis transmission link 50. In the illustrated example, the cross-member 1 comprises a housing 10 for the piezoelectric electric motor, said stator 36 of the motor being directly received in said housing housing. According to the illustrated example, the cross member 1 comprises a spar 11, a motor base 15, and a cover 14. The spar 11 extends from one movable section 6 to the other, and is a molded plastic part, of rectangular general section and comprising reinforcing ribs for allowing the spar 11 to support the weight of the engine and ancillary equipment arranged in the cross member 1. The engine base 15 is a plate of moderate thickness and substantially rectangular shape. The stator 36 is fixed on this motor base 15 by means of fixing screws 44 screwed into tapped holes 45 of the stator; the screw heads are hidden in countersinks 46 arranged in the body of the engine base 15; however, any other means of attachment may be suitable. The motor base 15 is mounted on the spar by means of a plurality of first elastic fastening clips 91, which are received in wells 92 facing each other arranged in the spar. In the example illustrated, the first fixing clips are hooks whose end 91 hooks onto shoulders 93 at the edge of wells 92. In the example illustrated, the cover 14 is intended to be fixed on the motor base 15 by means of a plurality of second resilient fixing clips 94. For example, the second elastic clips may take the form of hooks received in corresponding orifices 95 of the engine base 15, said orifices having a co-operating surface with the hook to retain the clip in position and therefore the cover 14 in the assembled position on the engine base 15. In the illustrated embodiment, a housing 10 is formed from the engine base 15 and the cover 14. According to alternative solutions, the engine base 15 could be made integrally with the spar 11, the stator then being fixed directly on the spar and the cover clipped on the spar.

The presence of such a housing 10 makes it possible to dispense with a casing specific to the piezoelectric motor, and thus to improve the physical integration to reduce the cost and weight of the solution. The piezoelectric motor 3 comprises a stator 36 with a ring 33 of piezoelectric elements, which is in the form of a flat peripheral ring disposed in a plane transverse to the Z axis. The piezoelectric motor 3 comprises a rotor 35 which is also in the form of a disk, for example thinner than the stator. The plurality of piezoelectric elements arranged in the ring 33 are connected by conductors to an electronic control unit (not shown in the figures) which makes it possible to create progressive waves in the circumferential direction of this piezoelectric ring. Said piezoelectric ring 33 is disposed against a peripheral zone 36c of the stator, such that the waves generated by the piezoelectric elements are transformed into mechanical waves transmitted to the stator 36. Moreover, a 'Belleville' type washer 34 exerts an axial force to press the rotor 35 against the stator 36, so that the mechanical waves generated at the stator 36 are transformed into circumferential forces exerted on the rotor 35 to put the latter in motion around the Z axis.

There is thus obtained an electric motor known as the piezoelectric motor type which can generate a rotational movement on the rotor 35, for example in a range of speeds between 100 and 400 revolutions / min, for example 200 revolutions / min.

The rotor comprises an axially centered grooved recess, marked 35a, which allows the rotor to transmit its rotational movement through the rotor shaft 37. This rotor shaft 37 comprises in the illustrated example a groove complementary to the shape of the rotor. axial recess 35a. The rotor shaft 37 extends along the vertical axis Z, passes through a central orifice of the rotor 36, and receives the first pinion 60 (drive gear) of the first angle gear 60,61. The first pinion 60 is immobilized on the control shaft 37 by means of an axial screw 39. The first pinion 60 of the first angle gear is equipped with a conical toothing inclined at 45 degrees with respect to its axis, said conical teeth being engaged with a complementary toothing of a second pinion 61 of the first angle gear (driven gear). The second pinion 61 of the first angle gear is integral with a sleeve 55 rotatably mounted about the transverse axis Y. In the example shown, the transmission link comprises a first rigid bar 50 on the right side which connects the sleeve 55 to a second bevel gear 62,64, by means of an end sleeve 57 (visible in FIG. 2), and another rigid left-hand bar 50 which connects the sleeve 55 in a manner similar to the adjustment mechanism on the opposite side.

Alternatively, the transmission link 50 could traverse completely the sleeve 55, in which case the transmission link would consist of a single piece, in this case a rigid bar 50. In an advantageous aspect, the electronic control board can be received in an auxiliary housing of the cross member (not shown), preferably near the engine. In the illustrated example, a nominal speed of rotation of the piezoelectric motor is chosen between 100 rpm and 400 rpm, preferably in the vicinity of 200 rpm. Such a moderate speed makes it possible to reduce the risks of noise inherent to the engine itself. In addition, the first bevel gear 60, 61 has a reduction ratio of 1, and therefore the transmission link (or links) 50 rotates at the same speed as the motor; its moderate pace also helps to reduce the risk of loud noise. Each adjustment mechanism 2 comprises a second angle gear 62,63; 64 and an intermediate shaft 8 oriented longitudinally along X1 (respectively X2), the intermediate shaft 8 being driven by the bevel gear and driving the nut. 9. The first gear 62 (drive gear) of the second bevel gear is formed integrally with an end sleeve 57 coupled to the end of the transmission link 50. The second gear 63; 64 (driven gear) ) is integrally mounted with an intermediate gear 89 and meshes with the first gear 62; the first and second gears comprise tapered teeth oriented at 45 degrees to their axis, which combine. The intermediate gear 89 is mounted integral with the intermediate shaft 8, for example as illustrated, the intermediate shaft has a grooved section 49 on which is received a correspondingly shaped hub of the intermediate gear 89. The intermediate gear 89 meshes directly with the captive rotating nut 9.

As illustrated in FIG. 4, each adjustment mechanism 2 comprises a housing made in the form of two half-shells 81, 82. The two half-shells 81,82 are assembled by clipping by means of hooks 87 which are locked on shoulders 88 located vis-à-vis the opposite half-shell. Furthermore, the half-shells 81, 82, once assembled, form bearings 83, 84, 85 which hold the intermediate shaft 8 and the captive rotating nut 9 in position in the casing while permitting their rotation of their axis. parallel to the longitudinal direction (X1 respectively X2). The end sleeve 57 is in turn received in an auxiliary bearing marked 56.

The reduction ratio of the second angular gearing gears is equal to 1. The rotational speed of the intermediate shafts 8 is therefore identical to that of the transmission link, namely in the illustrated example close to 200 rpm. .

It should be noted that the efficiency of such first and second angular gearing gears is between 80% and 95%. Thus the line loss between the motor 3 and the captive rotating nuts 9 is very limited, which makes it possible to choose a piezoelectric motor whose torque is of the order of 1 to 2 Newton-meters. It should be noted that the control of the longitudinal movements of the slideways may comprise start ramps and stop ramps which are managed by a microcontroller in the electronic control card, which makes it possible to reduce the operating noise in the phases of operation. start and stop phases. Similarly electromagnetic noise is reduced because of the absence of brushes and commutations generated by such brushes. In addition, the control electronics can also diagnose certain motor drive faults to facilitate diagnosis and repair. In the example illustrated in the figures, the motor 3 is located near the middle of the width available between the slides, but of course it could be otherwise, in particular the motor could be adjacent to one of the slides and by therefore the presence of a second transmission link is considered optional. It is thus possible to choose said position as a function of the need for storage space under the seat. Similarly, it should be noted that the fact of having a single motor arranged on the crossbar connecting the two slides is an advantageous arrangement from the economic and technical point of view with respect to a configuration where each slide would have its own motor. The single motor ensures a very simple mechanical synchronization of the two slides. It should be noted that the angle of return mechanism 2 shown in particular in FIG. 4 makes it possible to raise the axis 20 of the transmission link Y with respect to the axes X1, X2 of the screws 90. This upward shift makes it possible to increase the height available between the underside of the seat and the floor. Such an angle of return mechanism 2 shown in particular in Figure 4 could be used in combination with any other type of engine integrated in the crossbar.

Claims (13)

REVENDICATIONS1. A set of slides for a vehicle seat, comprising: - two parallel rails (5) extending in a longitudinal direction (X) and each having a screw and nut adjusting mechanism (2), - at least one cross member (1) extending mainly in a transverse direction (Y) and interconnecting the two slides, and supported at each of its two ends respectively by one of the two rails, characterized in that a single piezoelectric motor (3) is arranged on the cross member and coupled to the adjusting mechanisms (2) by at least one transmission link (50). A slide assembly as claimed in claim 1, wherein said crosshead comprises a housing (10) forming a housing of the piezoelectric electric motor, said motor comprising a stator directly received in the housing housing, and a rotor coupled to the housing mechanisms. setting (2) by the at least one transmission link. A slide assembly according to claim 2, wherein the rotor is rotatably mounted about a vertical axis (Z) perpendicular to the longitudinal (X) and transverse (Y) directions, the assembly further comprising a first deflection angle at the output of the rotor shaft. 4. Slide assembly according to one of claims 1 to 3, wherein the rotational speed of the rotor is between 100 and 400 revolutions per minute and preferably in the vicinity of 200 revolutions per minute. 5. Set of slides according to one of claims 1 to 4, wherein each of the adjusting mechanisms (2) comprises a second angular gear and an intermediate shaft (8) arrange longitudinally, the intermediate shaft being driven by the angle gear and driving a captive rotating nut (9). The slide assembly of claim 2, wherein the cross member includes a spar (11), a motor base (15) and a cover (14), the cover closing the housing housing (10). A slide assembly as claimed in claim 6, wherein the motor base (15) is attached to the spar (11) by means of first resilient retaining clips. The slide assembly of claim 6, wherein the cover (14) is attached to the motor base by means of second resilient retaining clips. 9. Set of slides according to one of claims 1 to 8, comprising an electronic card adapted to control the motor. 15 10.A set of slides according to one of claims 1 to 9, wherein the transmission link comprises on each side a rigid bar extending between the drive device and the adjustment mechanism. 20 11.A slide assembly according to one of claims 1 to 10, wherein the transmission link (50) comprises a first bar extending from one of the two adjustment mechanisms to the engine and a second bar s' extending from the motor to the other adjusting mechanism. The slide assembly according to one of claims 1 to 10, wherein the transmission link is a rigid bar (50) extending from one adjusting mechanism to the other. 30 13. Vehicle seat comprising a seat carried by a set of rails (5) according to any one of the preceding claims.