Motor vehicle seat headrest
The headrest design addresses the challenge of maintaining contact between stems and bearings during motorized height adjustment by using non-retractable elastic projections, resulting in reduced friction and parasitic noises, and lower power requirements for the motorized system.
Patent Information
- Application Number
- FR2023011639
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2023-02-28
- Filing Date
- 2023-10-26
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2043-10-26
AI Technical Summary
Existing headrest designs for motor vehicles face challenges in maintaining permanent contact between stems and bearings during motorized height adjustment, leading to parasitic noises while trying to minimize friction force to avoid over-sizing the engine.
The headrest design incorporates two parallel liaison stems mounted at the top of a molded energy absorption plastic box, with bearings that have non-retractable elastic projections around the orifice periphery to ensure permanent contact with the stems, minimizing friction through elastic legs.
This design achieves permanent contact between stems and bearings, minimizing friction and preventing parasitic noises, while simplifying the mechanism and reducing the power requirements for the motorized adjustment system.
Smart Images
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Abstract
Description
Title of the invention: Headrest for a motor vehicle seat
[0001] The invention relates to a headrest for a motor vehicle seat.
[0002] It is known, in particular from document EP-3 487 726, to produce a headrest of motor vehicle seat, said headrest comprising: • two parallel connecting rods to said seat, said rods being intended to be mounted at the top of the back of said seat, • a molded plastic housing for absorbing energy in the event of a passenger's head hitting said headrest, said housing being provided with a headrest cushion, • two sets of bearings made of molded plastic material, each of said sets comprising an upper bearing and a lower bearing receiving one of said rods, said bearings being mounted by fitting into housings provided in said housing, said bearings being provided with an orifice for sliding reception of the corresponding rod so as to allow adjustment of the height of said housing, said bearings being further provided with peripheral tabs resulting from molding, said tabs projecting radially and being elastically retractable inwards, said tabs bearing against the internal wall of said housings so as to keep said bearings locked in said housings.
[0003] In the known embodiment, the bearings are provided with retractable tabs projecting inwards from the bearing orifices and actuated inwards by metal spring blades, in order to allow the rods to be pinched in the bearings.
[0004] Such an arrangement is well suited in the case of manual adjustment of the height of the housing where it is required to implement a sufficient friction force between the rods and bearings, so that the headrest can remain in the chosen adjustment position before it is locked in said position.
[0005] However, such an arrangement is not relevant in the case of a headrest where the housing is operated in a motorized manner.
[0006] Indeed, in such a case, we seek to ensure, economically, permanent contact between the rods and bearings in order to avoid parasitic noise, but while minimizing the friction force between the two so as not to have to oversize the motor in power.
[0007] The aim of the invention is to propose a headrest which makes it possible to meet these expectations.
[0008] To this end, the invention proposes a headrest for a motor vehicle seat, said headrest including: • two parallel connecting rods to said seat, said rods being intended to be mounted at the top of the back of said seat, • a molded plastic housing for absorbing energy in the event of a passenger's head hitting said headrest, said housing being provided with a headrest cushion, • two sets of bearings made of molded plastic material, each of said sets comprising a top bearing and a bottom bearing receiving one of said rods, said bearings being mounted by fitting into housings provided in said housing, said bearings being provided with an orifice for sliding reception of the corresponding rod so as to allow adjustment of the height of said housing, said bearings being further provided with peripheral tabs resulting from molding, said tabs projecting radially and being elastically retractable inwards, said tabs bearing against the internal wall of said housings so as to keep said bearings locked in said housings,
[0009] said headrest further having the following characteristics: • it further comprises a motorized device for sliding said housing on said rods, so as to allow its height to be adjusted, • the periphery of said orifice is provided with at least three projections resulting from molding, non-elastically retractable, for guiding the corresponding rod, said projections being arranged so that said rod is substantially in contact with them.
[0010] In this description, the terms of positioning in space (longitudinal, transverse, vertical, upper, high, low, etc.) are considered relative to the longitudinal (X), transverse (Y) and vertical (Z) directions in which the vehicle extends, the headrest being mounted in said vehicle in use.
[0011] As for the terms “radially” and “diametrically”, they are taken with reference to the extension axis of a rod.
[0012] With the proposed arrangement, permanent contact is ensured between the rods and bearings, while minimizing the friction force between them.
[0013] Indeed, the elastic tabs alone make it possible to guarantee such contact, through the projections, while exerting a moderate force making it possible to limit the friction force between the rods and bearings.
[0014] This makes it possible to dispense with the retractable tabs, known from the prior art, actuated by deployment towards the inside of the orifices by metal spring blades, said tabs being replaced by the non-retractable projections.
[0015] This results in a simplification of the bearings, linked to the elimination of the spring blades, and also an economic gain linked to the use of a non-oversized power motor.
[0016] Other features and advantages of the invention will appear in the following description, given with reference to the attached figures, in which:
[0017] [Fig-1] is a partial schematic representation in perspective of a headrest according to one embodiment,
[0018] [Fig.2] is a schematic perspective representation of a bearing according to one embodiment, said bearing being mounted in its housing.
[0019] With reference to the figures, a headrest 1 for a motor vehicle seat is described, said headrest comprising: • two parallel rods 2 connecting said seat, said rods being intended to be mounted at the top of the back of said seat, • a housing 3 made of molded plastic material for absorbing energy in the event of a passenger's head hitting said headrest, said housing being provided with a headrest cushion (not shown), • two sets of bearings made of molded plastic material, each of said sets comprising an upper bearing 4 and a lower bearing 5 receiving one of said rods, said bearings being mounted by fitting into housings 6 provided in said housing, said bearings being provided with an orifice 7 for sliding reception of the corresponding rod 2 so as to allow adjustment of the height of said housing, said bearings being further provided with peripheral tabs 8a, 8b resulting from molding, said tabs projecting radially and being elastically retractable inwards, said tabs bearing against the internal wall 9 of said housings so as to keep said bearings locked in said housings,
[0020] said headrest further having the following characteristics: • it further comprises a motorized device, not shown, for actuating the sliding of said housing on said rods, so as to allow its height to be adjusted, • the periphery of said orifice is provided with at least three projections 10 resulting from molding, non-elastically retractable, for guiding the corresponding rod 2, said projections being arranged so that said rod is substantially in contact with them.
[0021] According to the embodiment shown, the projections 10 are distributed in an isoangular manner, said projections here being four in number separated from each other by an angle of 90°.
[0022] This guarantees that the rods 2 are locked in the orifices 7 both in the longitudinal X and transverse Y directions.
[0023] According to the embodiment shown, the projections 10 are in the form of a boss allowing substantially point contact with the corresponding rod 2, so as to minimize friction.
[0024] According to one embodiment, the projections 10 are arranged so that the corresponding rod 2 cannot move in an orifice 7 by more than 0.25 mm in the transverse Y and longitudinal X directions.
[0025] According to the embodiment shown, the headrest 1 comprises a first set of legs 8a arranged substantially diametrically opposite each other in the transverse direction Y, so as to allow for play to be taken up in said direction.
[0026] According to the embodiment shown, the first set of legs is formed by two pairs of legs 8a arranged diametrically opposite.
[0027] According to the embodiment shown, the headrest 1 further comprises a second set of legs 8b arranged substantially diametrically opposite each other in the longitudinal direction X, so as to allow for play to be taken up in said direction.
[0028] According to the embodiment shown, the second set of legs is formed by two legs 8b arranged diametrically opposite.
[0029] According to one embodiment, the bearings 4, 5 are based on polyoxymethylene (POM), so that the legs 8a, 8b have an elasticity making it possible to compensate for the dimensional variations of the housing 3 linked to the variations in temperature, said housing being made for example from low density polyethylene (HDPE) which has a strong propensity to expand when the temperature increases.
[0030] The choice of such a material, or a similar material, to produce the bearings 4, 5 makes it possible to avoid the use of spring blades to ensure the deployment of the legs 8a, 8b outwards.
[0031] According to the embodiment shown, the bearings 4, 5 are provided with an indexing means 11 - here in the form of a notch - cooperating with a reciprocal means 12 - here in the form of a projection penetrating into said notch - provided in the corresponding housing 6, so as to block them in rotation.
[0032] According to the embodiment shown, the legs 8a, 8b comprise a connecting end 13 to the rest of the bearing 4, 5 and a free end 14 bearing against the internal wall 9 of the corresponding housing 6.
[0033] According to an embodiment not shown, the motorized device for actuating the housing 3 comprises: • a motor mounted integrally with said housing, said motor rotating a vertically extending worm screw, said screw being rotatably mounted on said housing, • a nut secured to a spacer connecting the upper ends of the rods 2 together, said screw cooperating with said nut so as to allow a moving said housing by rotating said screw.
Claims
Claims
1. Headrest (1) for a motor vehicle seat, said headrest comprising: • two parallel rods (2) for connecting to said seat, said rods being intended to be mounted at the top of the back of said seat, • a housing (3) made of molded plastic material for absorbing energy in the event of a passenger's head hitting said headrest, said housing being provided with a headrest cushion, • two sets of bearings made of molded plastic material, each of said sets comprising a top bearing (4) and a bottom bearing (5) receiving one of said rods, said bearings being mounted by fitting into housings (6) provided in said housing, said bearings being provided with an orifice (7) for slidingly receiving the corresponding rod (2) so as to allow adjustment of the height of said housing, said bearings being further provided with peripheral tabs (8a, 8b) produced by molding,said legs projecting radially and being elastically retractable inwards, said legs bearing against the internal wall (9) of said housings so as to keep said bearings locked in said housings, said headrest being characterized in that: • it further comprises a motorized device for sliding said housing on said rods, so as to allow its height adjustment, • the periphery of said orifice is provided with at least three projections (10) resulting from molding, not elastically retractable, for guiding the corresponding rod (2), said projections being arranged so that said rod is substantially in contact with them.,
2. Headrest (1) according to claim 1, characterized in that the projections (10) are distributed iso-angularly.
3. Headrest (1) according to any one of the preceding claims, characterized in that the projections (10) are boss-shaped allowing substantially point contact with the corresponding rod (2).
4. Headrest (1) according to any one of the preceding claims, characterized in that the projections (10) are arranged so that the corresponding rod (2) cannot move in an orifice (7) by more than 0.25 mm in the transverse (Y) and longitudinal (X) directions.
5. Headrest (1) according to any one of the preceding claims, characterized in that it comprises a first set of legs (8a) arranged substantially diametrically opposite in a transverse direction (Y), so as to allow play to be taken up in said direction.
6. Headrest (1) according to the preceding claim, characterized in that it further comprises a second set of legs (8b) arranged substantially diametrically opposite in a longitudinal direction (X), so as to allow play to be taken up in said direction.
7. Headrest (1) according to any one of the preceding claims, characterized in that the bearings (4, 5) are provided with an indexing means (11) cooperating with a reciprocal means (12) provided in the corresponding housing, so as to block them in rotation.
8. Headrest (1) according to any one of the preceding claims, characterized in that the legs (8a, 8b) comprise a connecting end (13) to the rest of the bearing (3) and a free end (14) bearing against the internal wall (9) of the corresponding housing (6).