Device for moving a motor vehicle seat from front to rear

Abstract

The invention relates to a device (1) for moving a motor vehicle seat, comprising a first and second slide (2) parallel to one another, a rectilinear bridge (4) connecting the two slides (2), a motor (5) driving, via a first transmission means, a first screw (8) parallel to the first slide (2) and, via a second transmission means, a second screw (9) parallel to the second slide, the first screw (8) translating a first nut (10) rigidly connected to the movable portion of the first slide (2) and the second screw (9) translating a second nut (11) rigidly connected to the movable portion of the second slide, wherein the first transmission means and the second transmission means comprise pulleys (12, 13, 16, 17) and belts (14, 15).

Description

[0001] DESCRIPTION

[0002] TITLE: Device for moving a car seat back and forth

[0003] Technical field

[0004] The invention relates to a device for mobilizing a car seat in translation, from front to back and vice versa.

[0005] Prior art

[0006] It is known to produce a device for mobilizing a car seat in translation from front to back and vice versa, comprising two slides. Each slide comprises a fixed part secured to the floor of the vehicle and a movable part secured to the seat. The slides are rectilinear. They are substantially parallel to each other and to the translational movement. They are arranged substantially horizontally. The device further comprises a rectilinear bridge connecting the two slides in a manner substantially perpendicular to the two slides. The device further comprises a motor. The motor drives, via a first transmission means, a first actuator mobilizing the first slide and via a second transmission means a second actuator mobilizing the second slide.

[0007] According to an embodiment of the prior art, the motor is arranged aligned with the bridge, i.e. perpendicular to the two slides and comprises a rotating shaft having two outputs / power take-offs, on either side of the motor, along its axis. Each of the two transmission means comprises a flexible shaft connected to one of the outputs of the motor shaft and transmitting the rotation of the motor to a speed reducer arranged at the slide. The speed reducer comprises a driving worm screw and a driven pinion, driving the movable part of the slide in translation.

[0008] Such a system has several drawbacks. On the one hand, the presence of gears in the two reducers and the flexible shafts produce significant noise. Its mechanical efficiency is relatively limited to 10-15%. Significant vibrations are transmitted to the slides and the seat frame. Its speed is limited. Assembling the system with the slides is difficult and unreliable. The clutch of the flexible shafts is difficult to control and is also difficult to synchronize between the two slides. Also, its principle is no longer suitable for modern uses and is the subject of criticism from users.

[0009] The invention proposes to modify the principle of such a device to obtain a more efficient device, allowing faster movement, transmitting less vibration and being quieter.

[0010] Summary of the invention

[0011] For this purpose, the invention relates to a device for mobilizing a car seat in translation from front to back and vice versa, comprising a first slide and a second slide substantially parallel to each other, parallel to the translation movement and substantially horizontal, a rectilinear bridge connecting the two slides and substantially perpendicular to the two slides, a motor driving, via a first transmission means, a first screw substantially parallel to the first slide and, via a second transmission means, a second screw substantially parallel to the second slide, the first screw driving in translation a first nut secured to the movable part of the first slide and the second screw driving in translation a second nut secured to the movable part of the second slide, where the first transmission means and the second transmission means comprise pulleys and belts.

[0012] Particular features or embodiments, usable alone or in combination, are:

[0013] - the motor is integrated into the bridge, the motor shaft being perpendicular to the axis of the bridge,

[0014] - the first transmission means comprises a first driving pulley, driven by the motor shaft, driving a first belt, driving a first driven pulley, driving the first screw and the second transmission means comprises a second driving pulley, driven by the motor shaft, driving a second belt, driving a second driven pulley, driving the second screw,

[0015] - a driving pulley has a diameter smaller than the diameter of a driven pulley,

[0016] - the device also comprises, between the motor and the first transmission means and between the motor and the second transmission means, a speed reducer,

[0017] - the speed reducer comprises a third driving pulley, driven by the motor shaft, driving a third belt, driving a third driven pulley, driving the first driving pulley and the second driving pulley, where the third driving pulley has a diameter smaller than the diameter of the third driven pulley,

[0018] - the belts are “Poly-V” belts (registered trademark),

[0019] - the belts are toothed belts, equipped with a tensioner,

[0020] - the motor is a brushless DC motor and its control unit is designed to drive a progressive speed reduction during stops,

[0021] - the motor is a direct current motor equipped with a mechanical torque limiter.

[0022] Brief description of the drawings

[0023] The invention will be better understood by reading the following description, given solely by way of example, and with reference to the appended figures in which:

[0024] [Fig. 1] shows, in perspective view, a device according to the invention, seen from the outside, [Fig. 2] shows, in perspective view, the device of figure 1, a slide removed, and a transparent front plate, in order to reveal the constituents,

[0025] [Fig. 3] shows, in perspective view, a speed reducer,

[0026] [Fig. 4] shows, in perspective view, the belt transmission of the device of Figure 1.

[0027] Description of the embodiments

[0028] With reference to Figures 1 and 2, the invention relates to a device 1 for mobilizing a car seat in translation from front to back and vice versa. This device 1 comprises a first slide 2 and a second slide 3 substantially parallel to each other, parallel to the translation movement and substantially horizontal. The device 1 also comprises a bridge 4. This bridge 4 is rectilinear and connects the two slides

[0029] 2, 3. It is substantially perpendicular to the two slides 2, 3. The device 1 also comprises a rotary motor 5. This motor 5 drives, via a first transmission means, a first screw 8 substantially parallel to the first slide 2 and via a second transmission means, a second screw 9 substantially parallel to the second slide

[0030] 3.

[0031] In its rotation, the first screw 8 drives a first nut 10. This first nut 10 is integral with the movable part of the first slide 2 and is locked in rotation relative to the fixed part. Similarly, the second screw 9 drives a second nut 11. This second nut 11 is integral with the movable part of the second slide 3 and is locked in rotation relative to the fixed part.

[0032] According to one characteristic, the first transmission means and the second transmission means comprise pulleys 12, 13, 16, 17 and belts 14, 15.

[0033] The use of pulleys and belts is advantageous in that a device 1 is obtained that is significantly less noisy due to the elimination of bearings on toothed wheels, particularly worm wheels, and of the friction and beating of the flexible shafts. In addition, such use transmits significantly less vibration, thanks to the damping provided by the belts 14, 15. Mechanical efficiency is improved due to the elimination of the flexible shafts, which are the source of significant friction. Another advantage of using a pulley and belt system is that in the event of possible desynchronization, between the first screw 8 and the second screw 9, it is possible to reset the synchronization by slipping, without damaging the components.

[0034] According to another characteristic, the motor 5 is integrated into the bridge 4. The shaft of the motor 5 is arranged perpendicular to the axis of the bridge 4. It can be arranged in any orientation perpendicular to the axis of the bridge 4. However, for reasons of space requirement and ease of integration, the motor 5 is preferably arranged such that its axis is horizontal. Consequently, the shaft of the motor 5 is advantageously parallel to the first screw 8 and to the second screw 9. This is advantageous for a belt transmission.

[0035] The bridge 4 can be arranged substantially in any forward / rearward position relative to the slides 2, 3. It can be arranged at the rear, in an intermediate position or even at the front. The rear position has the disadvantage of being exposed to impacts, typically from the rear of the seat. The intermediate position is not always available, particularly for certain electric vehicles, for which the height under the seat is limited. Also, the fact that bridge 4 of the device 1 can be arranged at any point, advantageously allows it to be preferably arranged at the front. Also, according to another characteristic, the bridge 4 is arranged between the front ends of the slides 2, 3. In order to reduce the height profile of the device 1, the motor 5 is advantageously arranged horizontally, at the rear of the bridge 4.

[0036] According to another characteristic, the first transmission means comprises a first driving pulley 12, driven by the shaft of the motor 5. This first driving pulley 12 drives, in turn, a first belt 14. The first belt 14 drives, in turn, a first driven pulley 16. This first driven pulley 16 drives the first screw 8, typically by being fixedly mounted on the axis of the first screw 8. Similarly, the second transmission means comprises a second driving pulley 13, driven by the shaft of the motor 5. This second driving pulley 13 drives, in turn, a second belt 15. The second belt 15 drives, in turn, a second driven pulley 17. The second driven pulley 17 drives the second screw 9, typically by being fixedly mounted on the axis of the second screw 9.

[0037] For reasons of synchronization between the two slides 2, 3 and screws 8, 9, the first transmission means and the second transmission means advantageously have the same speed reduction ratio. This can be achieved by using driving pulleys 12, 13 of the same diameters and driven pulleys 16,

[0038] 17 of the same diameters.

[0039] It is advantageous to have a speed reducer between motor 5 and screws 8, 9. However, this feature is not necessary. In the absence of a reducer, it is necessary to be able to precisely control the speed of motor 5 and this requires a low-speed, high-torque motor.

[0040] According to another characteristic, the two transmission means have a speed reduction ratio, preferably identical. One embodiment of such a reduction ratio consists of a driving pulley 12, 13 having a diameter smaller than the diameter of a driven pulley 16, 17. This does not, however, allow large reduction ratios.

[0041] Also, according to another characteristic, the device 1 further comprises, between the motor 5 and the first transmission means and between the motor 5 and the second transmission means, a speed reducer 18.

[0042] Such a speed reducer 18 can be produced according to different embodiments. According to a first option, it is possible to use a conventional gear reducer. However, such a choice does not go in the desired direction of noise reduction.

[0043] The applicant also proposes an innovative, gearless reducer. This reducer, the subject of another application by the applicant, is not described here. However, it can find its place in a device 1 according to the invention.

[0044] According to another characteristic, illustrated in figures 2, 3 and 4, the speed reducer

[0045] 18 is a pulley and belt mechanism. This reducer 18 comprises a third driving pulley 19, driven by the shaft of the motor 5. For this purpose, the third driving pulley 19 is fixedly mounted on the shaft of the motor 5. This third driving pulley 19 in turn drives a third belt 20. This third belt 20 in turn drives a third driven pulley 21. This third driven pulley 21 drives the first driving pulley 12 and the second driving pulley 13, typically via an intermediate drive shaft, securing the three pulleys 12, 13, 21. In order to obtain a speed reduction, the third driving pulley 19 has a diameter smaller than the diameter of the third driven pulley 21.

[0046] According to another characteristic, at least one and advantageously all of the belts 14, 15, 20 are “Poly-V” belts (registered trademark). A “Poly-V” belt (registered trademark), in a known manner, has a transverse profile in the shape of a triangular signal and a continuous longitudinal profile. The pulleys are adapted to this profile. The “Poly-V” profile (registered trademark) makes it possible to increase the contact surface between the pulley and the belt, thus providing a better driving effect. Such a type of belt is advantageous in that it does not require a tensioner. It also advantageously has greater elasticity, thus providing better damping. In addition, such a type of belt, in that it has a continuous longitudinal profile, is 20% less noisy compared to a toothed belt, also called a synchronous belt.

[0047] According to another feature, an alternative to a "Poly-V" belt (registered trademark) is a toothed belt. From zero to all belts 14, 15, 20 can be toothed belts. Such a toothed belt is advantageously equipped with a tensioner.

[0048] According to another feature, the motor 5 is a brushless direct current (BLDC) motor. Such a motor 5, in that it produces abrupt stops, is advantageously combined with a control unit designed to control a progressive speed reduction during stops.

[0049] According to another feature, the motor 5 is a direct current motor. Such a motor is advantageously equipped with a mechanical torque limiter. This makes it possible to avoid jolts and thus extends the service life of the driven pulley / belt mechanisms.

[0050] The invention has been illustrated and described in detail in the drawings and the preceding description. The foregoing description should be considered illustrative and given by way of example and not as limiting the invention to this description alone. Numerous alternative embodiments are possible.

[0051] List of reference signs

[0052] 1: device,

[0053] 2: first slide,

[0054] 3: second slide,

[0055] 4: bridge,

[0056] 5: engine, 8: first screw,

[0057] 9: second screw,

[0058] 10: first nut,

[0059] 1 1: second nut, 12: first driving pulley,

[0060] 13: second driving pulley,

[0061] 14: first belt,

[0062] 15: second belt,

[0063] 16: first driven pulley, 17: second driven pulley,

[0064] 18: speed reducer,

[0065] 19: third driving pulley,

[0066] 20: third belt,

[0067] 21: third driven pulley.

Claims

CLAIMS 1. Device (1) for mobilizing a car seat in translation from front to back and vice versa, comprising a first slide (2) and a second slide (3) substantially parallel to each other, parallel to the translation movement and substantially horizontal, a rectilinear bridge (4) connecting the two slides (2, 3) and substantially perpendicular to the two slides (2, 3), a motor (5) driving, via a first transmission means, a first screw (8) substantially parallel to the first slide (2) and, via a second transmission means, a second screw (9) substantially parallel to the second slide (3), the first screw (8) driving in translation a first nut (10) secured to the movable part of the first slide (2) and the second screw (9) driving in translation a second nut (11) secured to the movable part of the second slide (3),characterized in that the first transmission means and the second transmission means comprise pulleys (12, 13, 16, 17) and belts (14, 15)., 2. Device (1) according to claim 1, wherein the motor (5) is integrated into the bridge (4), the shaft of the motor (5) being perpendicular to the axis of the bridge (4).

3. Device (1) according to any one of claims 1 or 2, wherein the first transmission means comprises a first driving pulley (12), driven by the motor shaft (5), driving a first belt (14), driving a first driven pulley (16), driving the first screw (8) and the second transmission means comprises a second driving pulley (13), driven by the motor shaft (5), driving a second belt (15), driving a second driven pulley (17), driving the second screw (9).

4. Device (1) according to the preceding claim, where a driving pulley (12, 13) has a diameter smaller than the diameter of a driven pulley (16, 17).

5. Device (1) according to any one of claims 1 to 4, further comprising, between the motor (5) and the first transmission means and between the motor (5) and the second transmission means, a speed reducer (18).

6. Device (1) according to claim 5 when dependent on claim 3, wherein the speed reducer (18) comprises a third driving pulley (19), driven by the motor shaft (5), driving a third belt (20), driving a third driven pulley (21), driving the first driving pulley (12) and the second driving pulley (13), wherein the third driving pulley (19) has a diameter smaller than the diameter of the third driven pulley (21).

7. Device (1) according to any one of claims 1 to 6, wherein the belts (14, 15, 20) are “Poly-V” belts (registered trademark).

8. Device (1) according to any one of claims 1 to 6, wherein the belts (14, 15, 20) are toothed belts, equipped with a tensioner.

9. Device (1) according to any one of claims 1 to 8, wherein the motor (5) is a brushless DC motor and its control unit is designed to control a progressive speed reduction during stops.

10. Device (1) according to any one of claims 1 to 8, wherein the motor (5) is a direct current motor equipped with a mechanical torque limiter.

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