Device for moving motor vehicle seat backwards and forwards

Abstract

The invention relates to a device (1) for moving a motor vehicle seat, comprising: a first and a second slide (2) parallel to each other; the linear bridging piece (4) is connected with the two slide ways (2); a motor (5) driving a first screw (8) parallel to the first slide (2) via a first transmission mechanism and a second screw (9) parallel to the second slide via a second transmission mechanism, the first slide (8) driving in translation a first nut (10) integral with the movable part of the first slide (2), and the second screw (9) drives in translation a second nut (11) integral with the movable part of the second slide, wherein the first and second transmission mechanisms comprise pulleys (12, 13, 16, 17) and belts (14, 15).

Description

TECHNICAL FIELD

[0001] The invention relates to a device for translating a motor vehicle seat backwards and forwards and vice versa. BACKGROUND

[0002] It is known to produce a device for translating a motor vehicle seat backwards and forwards and vice versa, comprising two slides. Each slide comprises a fixed part integral with the vehicle floor and a mobile part integral with the seat. The slides are rectilinear. They are substantially parallel to each other and to the translation movement. They are arranged substantially horizontally. The device also comprises a rectilinear bridge connecting to the two slides substantially perpendicularly to the two slides. The device also comprises an electric motor. The electric motor drives a first actuator moving a first slide via a first transmission mechanism and a second actuator moving a second slide via a second transmission mechanism.

[0003] According to one embodiment of the background art, the electric motor is aligned with the bridge, i.e. perpendicular to the two slides, and comprises a rotating shaft having two power outputs / outlets on both sides of the electric motor along its axis. Each of the two transmission mechanisms comprises a flexible shaft connected to one of the outputs of the electric motor shaft and transmitting the rotation of the electric motor to a reducer arranged at the slide. The reducer comprises a driving worm and a driven pinion, driving the mobile part of the slide in translation.

[0004] This system has several drawbacks. On the one hand, the presence of gears in the two reducers and flexible shafts generates a lot of noise. Its mechanical efficiency is relatively limited, between 10 and 15%. Significant vibrations are transmitted to the frame of the slide and the seat. Its speed is limited. Assembling the system with the slides is difficult and unreliable. The clutches of the flexible shafts are difficult to control and also to synchronize between the two slides. Moreover, its principle no longer adapts to modern uses and is the subject of user criticism.

[0005] The invention proposes to modify the principle of such a device to obtain a more efficient device allowing faster movement, transmitting fewer vibrations and less noise. SUMMARY

[0006] The object of the present invention is a device for translating a motor vehicle seat backwards and forwards and vice versa, comprising: a first 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 mechanism, a first screw substantially parallel to the first slide, and, via a second transmission mechanism, a second screw substantially parallel to the second slide, the first screw translating a first nut integral with the active part of the first slide, and the second screw translating a second nut integral with the active part of the second slide, wherein the first and second transmission mechanisms comprise pulleys and belts.

[0007] Particular features or embodiments, which can be used individually or in combination, are:

[0008] - the motor is integrated into the bridge, with the shaft of the motor perpendicular to the axis of the bridge,

[0009] - the first transmission mechanism comprises a first drive pulley driven by the shaft of the motor, driving a first belt, driving a first driven pulley, driving the first screw, and the second transmission mechanism comprises a second drive pulley driven by the shaft of the motor, driving a second belt, driving a second driven pulley, driving the second screw,

[0010] - the drive pulleys have a diameter smaller than the diameter of the driven pulleys,

[0011] - the device further comprises a reduction gear between the motor and the first transmission mechanism and between the motor and the second transmission mechanism,

[0012] - the reduction gear comprises a third drive pulley driven by the shaft of the motor, driving a third belt, driving a third driven pulley, driving the first and second drive pulleys, wherein the third drive pulley has a diameter smaller than the diameter of the third driven pulley,

[0013] - the belts are Poly-V belts (registered trademark),

[0014] - the belts are toothed belts equipped with a tensioner,

[0015] - the motor is a brushless DC motor and its control unit is designed to control a gradual slowdown during stopping,

[0016] - the motor is a DC motor equipped with a mechanical torque limiter. BRIEF DESCRIPTION OF DRAWINGS

[0017] The invention will be better understood by reading the following description, given solely by way of example, and in reference to the appended drawings, in which:

[0018] [ Figure 1 ] shows the device according to the invention from the outside in perspective view,

[0019] [ Figure 2 ] shows the device from the inside in perspective view, Figure 1 the device shown, with the removed slide, and showing the transparent front panel, in order to reveal the components,

[0020] [ Figure 3 ] shows the complete decelerator in perspective view,

[0021] [ Figure 4 ] shows the belt drive of the device shown in perspective view, Figure 1 DETAILED DESCRIPTION

[0022] With reference to Figure 1 and Figure 2 , the invention relates to a device 1 for translating a motor vehicle seat backwards and forwards, and vice versa. The device 1 comprises a first slide 2 and a second slide 3, which are substantially parallel to each other, parallel to the translation movement and substantially horizontal. The device 1 further comprises a bridge 4. The bridge 4 is rectilinear and connects the two slides 2, 3. It is substantially perpendicular to the two slides 2, 3. The device 1 further comprises a rotary electric motor 5. The motor 5 drives, via a first transmission mechanism, a first screw 8 substantially parallel to the first slide 2, and, via a second transmission mechanism, a second screw 9 substantially parallel to the second slide 3.

[0023] When it rotates, the first screw 8 drives a first nut 10. The first nut 10 is integral with the mobile part of the first slide 2 and is locked in rotation with respect to the fixed part. Likewise, the second screw 9 drives a second nut 11.

[0024] The second nut 11 is integral with the mobile part of the second slide 3 and is locked in rotation with respect to the fixed part.

[0025] According to one feature, the first transmission mechanism and the second transmission mechanism comprise pulleys 12, 13, 16, 17 and belts 14, 15.

[0026] The advantage of using pulleys and belts is that, by eliminating the bearings on the gears, in particular the worm, and the friction and play of the flexible shaft, a significantly less noisy device 1 can be obtained. Furthermore, this use transmits significantly less vibration, thanks to the damping provided by the belts 14, 15. By eliminating the need for a flexible shaft, which causes considerable friction, the mechanical efficiency is improved. Another advantage of using a pulley and belt system is that, in the event of any desynchronisation between the first screw 8 and the second screw 9, synchronisation can be reset by slipping, without damaging the components. ​

[0027] According to another feature, the electric motor 5 is integrated into the bridge 4. The shaft of the electric 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 and ease of integration, the electric motor 5 is preferably arranged so that its axis is horizontal. Thus, the shaft of the electric motor 5 is advantageously parallel to the first screw 8 and to the second screw 9. This is advantageous for the belt drive.

[0028] The bridge 4 can be arranged substantially in any front / rear position relative to the slides 2, 3. It can be located at the rear, in an intermediate position or at the front. The rear position has the drawback of being exposed to impacts, which generally come from the rear of the seat. The intermediate position is not always available, especially for certain electric vehicles with a limited height under the seat. Furthermore, the fact that the bridge 4 of the device 1 can be arranged at any point advantageously means that it is preferably positioned at the front. Furthermore, according to another feature, 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 electric motor 5 is advantageously arranged horizontally at the rear of the bridge 4.

[0029] According to another feature, the first transmission mechanism comprises a first drive pulley 12 driven by the shaft of the electric motor 5. This first drive pulley 12 in turn drives a first belt 14. The first belt 14 in turn drives a first driven pulley 16. This first driven pulley 16 generally drives the first screw 8 by being fixedly mounted on the axis of the first screw 8. Similarly, the second transmission mechanism comprises a second drive pulley 13 driven by the shaft of the electric motor 5. This second drive pulley 13 in turn drives a second belt 15. The second belt 15 in turn drives a second driven pulley 17. The second driven pulley 17 generally drives the second screw 9 by being fixedly mounted on the axis of the second screw 9.

[0030] Thanks to the synchronization between the two slides 2, 3 and the screws 8, 9, the first transmission mechanism and the second transmission mechanism advantageously have the same reduction ratio. This can be achieved by using drive pulleys 12, 13 with the same diameter and driven pulleys 16, 17 with the same diameter.

[0031] It is advantageous to install a reduction gear between the electric motor 5 and the screws 8, 9. However, this feature is not essential. Without a reduction gear, it is necessary to control the speed of the electric motor 5 precisely, which requires an electric motor with low speed and high torque.

[0032] According to another feature, the two transmission mechanisms have a reduction ratio that is preferably the same. One embodiment of such a reduction ratio consists of drive pulleys 12, 13 with a smaller diameter than the driven pulleys 16, 17. However, this does not allow a significant reduction ratio.

[0033] Furthermore, according to a further feature, the device 1 also comprises a reduction gear 18 between the electric motor 5 and the first transmission mechanism and between the electric motor 5 and the second transmission mechanism.

[0034] Such a reduction gear 18 can be designed in various ways. According to a first option, a conventional gear reduction can be used. However, such an option is not favourable for noise reduction.

[0035] The applicant also proposes an innovative gearless reduction gear. This reduction gear is not described here (i.e. subject of another claim of the applicant). However, it can also be used in the device 1 according to the invention.

[0036] According to a further feature, as shown in Figure 2 , Figure 3 and Figure 4 , the reduction gear 18 is a belt and pulley mechanism. The reduction gear 18 comprises a third drive pulley 19 driven by the shaft of the electric motor 5. To this end, the third drive pulley 19 is fixedly mounted on the shaft of the electric motor 5. This third drive 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 drive pulley 12 and the second drive pulley 13, generally via an intermediate drive shaft connecting the three pulleys 12, 13, 21. In order to reduce, the third drive pulley 19 has a diameter smaller than the diameter of the third driven pulley 21.

[0037] According to a further feature, at least one and advantageously all belts 14, 15, 20 are "Poly-V" belts (registered trademark). It is known that Poly-V belts (registered trademark) have a triangular signal-shaped transverse profile and a continuous longitudinal profile. The pulleys are adapted to this profile. The "Poly-V" profile (registered trademark) increases the contact surface between the pulley and the belt, thus providing a better driving effect. This type of belt has the advantage that it does not require a tensioner. Advantageously, it also has greater elasticity, thus providing improved damping. Furthermore, this type of belt is 20% less noisy than toothed belts (also known as synchronous belts) due to its continuous longitudinal profile.

[0038] According to a further feature, an alternative to the "Poly-V" belts (registered trademark) is a toothed belt. From zero to all belts 14, 15, 20 can be toothed belts. Such toothed belts are advantageously equipped with a tensioner.

[0039] According to a further feature, the electric motor 5 is a brushless direct current (BLDC) motor. Such an electric motor 5 is advantageously combined with a control unit designed to control a progressive deceleration during a stop due to its sudden stop.

[0040] According to another feature, motor 5 is a DC motor. This type of motor is advantageously equipped with a mechanical torque limiter. This prevents vibration and thus extends the service life of the driven pulley / belt mechanism.

[0041] The invention has been described in detail with reference to the accompanying drawings and the foregoing description. This should be considered illustrative and given by way of example, and not intended to limit the invention to this description alone. Many alternative embodiments may be adopted.

[0042] List of reference numerals

[0043] 1: Apparatus,

[0044] 2: First slide,

[0045] 3: Second slide,

[0046] 4: Bridging components,

[0047] 5: Motor

[0048] 8: First screw,

[0049] 9: Second screw,

[0050] 10: First nut,

[0051] 11: Second nut;

[0052] 12: First drive pulley,

[0053] 13: Second drive pulley,

[0054] 14: First zone,

[0055] 15: Second zone,

[0056] 16: First driven pulley,

[0057] 17: Second driven pulley,

[0058] 18: Speed ​​reducer

[0059] 19: Third drive pulley,

[0060] 20: Third zone,

[0061] 21: Third driven pulley.

Claims

1. An apparatus (1) for moving a motor vehicle seat backward and forward, and vice versa, said apparatus comprising: A first slide (2) and a second slide (3), the first slide and the second slide being substantially parallel to each other, parallel to translational movement and substantially horizontal; a linear bridge (4), the linear bridge connecting the two slides (2, 3) and substantially perpendicular to the two slides (2, 3); a motor (5), the motor driving a first screw (8) substantially parallel to the first slide (2) via a first transmission mechanism and a second screw (9) substantially parallel to the second slide (3) via a second transmission mechanism, the first screw (8) translatingly driving a first nut (10) integral with the movable portion of the first slide (2), and the second screw (9) translatingly driving a second nut (11) integral with the movable portion of the second slide (3), characterized in that the first transmission mechanism and the second transmission mechanism include pulleys (12, 13, 16, 17) and belts (14, 15).

2. The device (1) according to claim 1, wherein the motor (5) is integrated into the bridge (4), and the axis of the motor (5) is perpendicular to the axis of the bridge (4).

3. The device (1) according to any one of claims 1 or 2, wherein the first transmission mechanism includes a first drive pulley (12), the first drive pulley being driven by the shaft of the motor (5) to drive a first belt (14), drive a first driven pulley (16), and drive a first screw (8), and the second transmission mechanism includes a second drive pulley (13), the second drive pulley being driven by the shaft of the motor (5) to drive a second belt (15), drive a second driven pulley (17), and drive a second screw (9).

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

5. The apparatus (1) according to any one of claims 1 to 4, characterized in that, A speed reducer (18) is also included between the motor (5) and the first transmission mechanism and between the motor (5) and the second transmission mechanism.

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

7. The device (1) according to any one of claims 1 to 6, wherein the band (14, 15, 20) is a "Poly-V" band (registered trademark).

8. The device (1) according to any one of claims 1 to 6, wherein the belt (14, 15, 20) is a toothed belt equipped with a tensioner.

9. The 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 gradual deceleration during a stop.

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

Images