Device for detecting a user's intention to lock or unlock a motor vehicle door

Abstract

A device to be integrated into a handle of a vehicle door for detecting a user's intention to lock or unlock the door, with a casing therein that includes a contact detection element that detects a contact of a user's hand on the handle, where an area of contact of the handle is defined by an elastically deformable part, and the contact detection element includes a non-magnetic metal target that moves along a predetermined axis, a coil, a pre-stressed compressible element between the non-magnetic metal target and the coil, means for transmitting a movement of the elastic part to the non-magnetic metal target, and means for comparing a measured inductance of the coil and a predetermined threshold value of inductance for detecting the user's intention to lock or unlock the door.

Claims

1. A device (D) to be integrated into a motor vehicle door handle for detecting a user's intention to lock or unlock a motor vehicle door, comprising: a casing (B), that includes a contact detection element (100) that detects a contact of a user's hand on the door handle (10), a printed circuit (80) in electrical communication with the contact detection element, and a voltage source (Vcc) connecting to the printed circuit to energize the printed circuit, and an elastically deformable first part (52), which is elastically deformable along a predetermined axis (Y-Y), the first part presenting an area (50) of contact with an interior surface of the door handle (10), wherein the contact detection element (100) includes a non-magnetic metal target (40), beneath the elastically deformable first part and adapted to move along the predetermined axis (Y-Y) responsive to a deformation of said elastically deformable first part, a coil (20), connected to a capacitance (C1), forming with said capacitance (C1) an oscillating circuit having a natural resonance frequency, means (M1), provided on the printed circuit, for adjusting the frequency of the oscillating circuit to a predetermined frequency, a prestressed compressible element (30), located between the non-magnetic metal target (40) and the coil (20), means (51) for transmitting a movement of the first part (52) of the casing (B) to the non-magnetic metal target (40), means (M2), provided on the printed circuit, for measuring an inductance (L) of the coil (20), means (M3), provided on the printed circuit, for comparison between the measured inductance (L) and a predetermined threshold value of inductance (Ls), for detecting the user's intention to lock or unlock the door, and means (60), provided on the printed circuit, for controlling the adjustment means (M1), the measurement means (M2) and the comparison means (M3).

2. The device as claimed in claim 1, wherein the area (50) of contact with the door handle (10) is constituted by a protuberance of the first part (52).

3. The device as claimed in claim 1, wherein the predetermined frequency is less than or equal to the resonance frequency of the coil (20).

4. The device as claimed in claim 1, wherein the means (M2) for measuring an inductance (L) of the coil (20) comprise means for measuring the oscillation frequency of the coil (20).

5. The device as claimed in claim 4, wherein the means (M1) for adjusting the frequency of the oscillating circuit and the means (M2) for measuring the oscillation frequency are included in an inductance to digital converter (70) on the printed circuit.

6. The device as claimed in claim 1, wherein the casing (B) has a bottom (B), and a cover (C) positioned over the bottom (B) and formed by the elastically deformable first part (52), and wherein said casing (B) includes a second part (53), aligned with the first part (52) along the predetermined axis (Y-Y) and located in the bottom (B), and includes an area of pressure on the door handle (10).

7. The device as claimed in claim 6, wherein the pressure area is constituted by a local increased thickness of a surface of the bottom (B).

8. A motor vehicle door handle (10), comprising: a device (D) as claimed in claim 1, positioned in an interior of the door handle (10); and at least one elastically deformable area (Z1) aligned along the predetermined axis (Y-Y) with the contact area (50), and having dimensions greater than or equal to those of the contact area (50).

9. A motor vehicle comprising a device (D) as claimed in claim 1.

10. The device as claimed in claim 2, wherein the predetermined frequency is less than or equal to the resonance frequency of the coil (20).

11. The device as claimed in claim 2, wherein the means (M2) for measuring an inductance (L) of the coil (20) comprise means for measuring the oscillation frequency of the coil (20).

12. The device as claimed in claim 3, wherein the means (M2) for measuring an inductance (L) of the coil (20) comprise means for measuring the oscillation frequency of the coil (20).

13. The device as claimed in claim 2, wherein the casing (B) has a bottom (B), and a cover (C) that comprises the elastically deformable first part (52), and wherein said casing (B) includes a second part (53), aligned with the first part (52) along the predetermined axis (Y-Y) and located in the bottom (B), and includes an area of pressure on the door handle (10).

14. A device (D) for a motor vehicle door handle for detecting a user's intention to lock or unlock a motor vehicle door, comprising: a casing (B), configured to be fitted in an interior of the door handle, the casing having a cover element and a bottom element beneath the cover element; and a contact detection element (100) provided inside said casing, wherein the cover element comprises an elastically deformable first part that is elastically deformable along a predetermined axis (Y-Y), the first part including an area (50) that contacts an interior surface of the door handle (10), wherein the contact detection element (100) includes a non-magnetic metal target (40), beneath the elastically deformable first part and adapted to move along the predetermined axis (Y-Y) responsive to a deformation of said elastically deformable first part, a coil (20), beneath the non-magnetic metal target, and connected to a capacitance (C1) so as to form with said capacitance (C1) an oscillating circuit having a natural resonance frequency, a prestressed compressible element (30), located between the non-magnetic metal target (40) and the coil (20), means (M1) for adjusting the frequency of the oscillating circuit to a predetermined frequency, means (51) for transmitting a movement of the first part (52) of the casing (B) to the nonmagnetic metal target (40), means (M2) for measuring an inductance (L) of the coil (20), means (M3) for comparison between the measured inductance (L) and a predetermined threshold value of inductance (Ls), for detecting the user's intention to lock or unlock the door, and means (60) for controlling the adjustment means (M1), the measurement means (M2) and the comparison means (M3).

15. The device as claimed in claim 14, wherein the bottom element of the casing includes a second part (53), aligned with the first part (52) along the predetermined axis (Y-Y), the second part constituted by a local increased thickness of a surface of the bottom element that contacts an other interior surface of the door handle (10).

16. A door handle (10) for a door of a motor vehicle, comprising: a top portion and a bottom portion, enclosing an interior space; and a user detection device that detects a user's intention to lock or unlock the door of the motor vehicle, positioned beneath a surface of the top portion and above a surface of the bottom portion, wherein the user detection device includes a casing (B) inside the interior of the door handle, the casing having a cover element and a bottom element beneath the cover element, and a contact detection element (100) provided inside said casing, the cover element including an elastically deformable first part that is elastically deformable along a predetermined axis (Y-Y), the first part including an area (50) that contacts an interior surface of the top portion of the door handle (10), and wherein the contact detection element (100) includes a non-magnetic metal target (40), beneath the elastically deformable first part and adapted to move along the predetermined axis (Y-Y) responsive to a deformation of said elastically deformable first part, a coil (20), beneath the non-magnetic metal target, and connected to a capacitance (C1) so as to form with said capacitance (C1) an oscillating circuit having a natural resonance frequency, a prestressed compressible element (30), located between the non-magnetic metal target (40) and the coil (20), means (M1) for adjusting the frequency of the oscillating circuit to a predetermined frequency, means (51) for transmitting a movement of the first part (52) of the casing (B) to the nonmagnetic metal target (40), means (M2) for measuring an inductance (L) of the coil (20), means (M3) for comparison between the measured inductance (L) and a predetermined threshold value of inductance (Ls), for detecting the user's intention to lock or unlock the door, and means (60) for controlling the adjustment means (M1), the measurement means (M2) and the comparison means (M3).

17. The door handle as claimed in claim 16, wherein the bottom element of the casing includes a second part (53), aligned with the first part (52) along the predetermined axis (Y-Y), the second part constituted by a local increased thickness of a surface of the bottom element that contacts an interior surface of the bottom portion of the door handle (10).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other characteristics and advantages of the invention will be apparent from a reading of the following description and from an examination of the appended drawings, in which:

(2) FIG. 1, explained above, shows schematically the detection device D according to the prior art,

(3) FIG. 2, shows schematically the detection device D according to the invention,

(4) FIG. 3 shows schematically a sectional view taken along the axis Y-Y of the detection device D of FIG. 2 according to the invention.

(5) FIG. 4 shows schematically the adjustment means M1, the measurement means M2 and the comparison means M3 of the detection device D according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(6) The detection device D according to the invention is illustrated in FIG. 2.

(7) Said detection device D takes the form of a casing integrated into the handle 10, and comprises, as in the prior art, a printed circuit 80 and at least one element for detecting the contact of the user's hand on the handle, and a voltage source.

(8) However, by contrast with the prior art, in which the contact detection element was formed by a capacitive sensor (locking electrodes E1 or unlocking electrodes E2), the invention proposes that said contact detection element 100 comprise an inductive sensor, consisting of a non-magnetic metal target 40 and a coil 20 among other components.

(9) More particularly, the casing B comprises a first part 52, elastically deformable along a predetermined axis Y-Y, comprising an area 50 of contact with the handle 10, and the detection element 100 comprises: a non-magnetic metal target 40 adapted to move along the predetermined axis Y-Y; a coil 20, aligned along the axis Y-Y with the non-magnetic metal target 40, connected to a capacitance C1 (see FIG. 4), forming with said capacitance C1 an oscillating LC circuit having a natural resonance frequency, means M1 (see FIG. 4) for adjusting the frequency of the oscillating circuit consisting of the coil 20 and the capacitance C1 to a predetermined frequency, a compressible prestressed element 30, located between the target 40 and the coil 20, means 51 for transmitting a movement of the first part 52 to the non-magnetic metal target 40, means M2 (see FIG. 4) for measuring an inductance of the coil 20, means M3 (see FIG. 4) for comparison between the measured inductance and a predetermined threshold value of inductance, for detecting the user's intention to lock or unlock the door, and means 60 for controlling the adjustment means M1, the measurement means M2 and the comparison means M3.

(10) In this example, the detection element 100 is dedicated to the detection of the intention to lock, and replaces the prior art capacitive sensor for detecting locking, but the invention is applicable, mutatis mutandis, to the detection of the intention to unlock, as a replacement for the prior art capacitive sensor for detecting unlocking.

(11) The first part 52 of the casing B is elastically deformable along the axis Y-Y. The casing B being integrated into the handle 10, said first part 52 has one face located near the second outer surface S2 of the handle, and can be deformed when the user presses (see the arrow A in FIG. 3) on a locking area Z1 (see FIGS. 2 and 3) located on said second outer surface S2 of the handle 10. For this purpose, said first part B2 is aligned with the locking area Z1 along the axis Y-Y.

(12) The expression elastically deformable means that the first part 52 is: made of an elastic material, for example Bayblend T85MN, having a Young's modulus of 200 MPa at 25 C., having, for example, a thickness e2 which is less than the wall thickness e3 of the casing B outside this first part 52 (see FIG. 3). For example, e2=1 mm and e3=2 mm.

(13) The first part 52 comprises an area 50 of contact with the handle 10, which is aligned with the locking area Z1. Preferably, the contact area 50 is circular in shape.

(14) The dimensions of the contact area 50 in a plane P perpendicular to the axis Y-Y, and parallel to the second outer surface S2 of the handle 10 are defined, for example, on the basis of the dimensions of a finger of the user's hand.

(15) Preferably, the dimensions of the contact area 50 are smaller than the dimensions of the locking area Z1.

(16) In the embodiment shown in FIG. 3, the casing B is made in two parts, and comprises a cover C oriented toward the second surface S2 and a bottom B oriented toward the first surface S1. The cover C comprises a local protuberance (see FIG. 3), located at the top and in the middle according to the sectional view through Y-Y of the cover C, which forms the area 50 of contact with the handle 10.

(17) In a preferred embodiment of the invention, the handle 10 also comprises an elastically deformable area located facing the contact area 50 of the casing B. Advisably, the elastically deformable area is the locking area Z1, and its dimensions are at least greater than the dimensions of the contact area 50.

(18) The elastically deformable area of the handle 10 is made of a flexible material, for example the same material as the first part 52 (Bayblend, for example), and its thickness e1 is less than the thickness e0 of the second outer surface S2 of the handle 10 located around said elastically deformable area.

(19) The non-magnetic metal target 40 is adapted to move along the axis Y-Y. Said non-magnetic metal target 40 is made, for example, of aluminum or any other non-magnetic metal. The non-magnetic metal target 40 may be cylindrical in shape.

(20) The coil 20 consists of a winding of copper wire for example, etched on the printed circuit 80. Said coil 20 is electrically connected to a capacitance C1, thus forming an oscillating LC circuit, and is also connected to: the means M1 for adjusting the frequency of the oscillating circuit consisting of the coil 20 and the capacitance C1, the means M2 for measuring the inductance of the coil 20, the means M3 for comparison between the measured inductance and a threshold value of inductance.

(21) Preferably, the inductance measurement means M2 consist of means for measuring the oscillation frequency of the oscillating circuit consisting of the coil 20 and the capacitance C1, and are included, with the frequency adjustment means M1 (an oscillator, for example) in an inductance to digital converter 70 (see FIG. 4).

(22) The comparison means M3 are provided in software form.

(23) The control means 60 consist of a microcontroller 60, and the comparison means M3 are, for example, integrated into the microcontroller 60, supplied with a voltage Vcc.

(24) The microcontroller 60, the inductance to digital converter 70, the coil 20 and the capacitance C1 are integrated into the printed circuit 80.

(25) The compressible prestressed element 30 is located between the non-magnetic metal target 40 and the coil 20, and is made, for example, of EPDM (ethylene propylene diene monomer), or more precisely of a flexible closed-cell foam which is highly flexible and withstands temperatures in the range from 40 C. to +85 C.

(26) The compressible prestressed element 30 undergoes two successive prestresses, namely a first prestress during its assembly into the casing B, then a second prestress during the assembly of the casing B into the handle 10.

(27) Being located between the non-magnetic metal target 40 and the coil 20, when the casing B has been integrated into the handle 10, the thickness of said compressible prestressed element 30, when compressed, provides an initial distance d0 between the non-magnetic metal target 40 and the coil 20.

(28) In a preferred embodiment, the casing B also comprises, in its bottom B, a second part 53 which is an area of pressure on the handle 10, and is aligned with the first part 52 along the axis YY.

(29) Said second part 53 takes the form, for example, of a local increased thickness of the bottom B of the casing B.

(30) The means 51 for transmitting a movement of the first part 52 to the non-magnetic metal target 40 take the form of two arms 51 extending the first part 52 along the axis Y-Y toward the non-magnetic metal target 20. The transmission means 51 may also take the form of a hollow cylinder connecting the first part 52 to the non-magnetic metal target 20 along the axis Y-Y.

(31) When the user presses on the locking area Z1 (see arrow A in FIG. 3), that is to say on the deformable area of the handle 10, said deformable area and the first part 52 (also elastically deformable), which is in contact with the deformable area via the contact area 50, are deformed and cause the transmission means 51 to move along the axis Y-Y. The transmission means 51 then press on the non-magnetic metal target 40 and transmit the movement to said non-magnetic metal target 40. Said non-magnetic metal target 40 moves in its turn, and compresses the compressible prestressed element 30. As it is compressed, the compressible prestressed element 30 approaches said non-magnetic metal target 40 of the coil 20. At the end of the pressing action, the final distance d1 between the non-magnetic metal target 40 and the coil 20 is less than the initial distance d0 before pressing.

(32) It should be noted that said elastically deformable area located on the handle 10 thus enables the movement of the non-magnetic metal target 40 to be extended toward the coil 20, without affecting the overall rigidity of the handle 10.

(33) For example, if there is a force of 10 N exerted by the user on the locking area Z1 of the handle 10, and an initial distance d0 of about 1 mm between the non-magnetic metal target 40 and the coil 20, the movement of the non-magnetic metal target 40 during pressing varies from about 20 m to 100 m, and the final distance d1 between the non-magnetic metal target 40 and the coil is then in the range from 0.9 mm to 0.98 mm.

(34) This movement from the initial distance d0 to the final distance d1 modifies the inductance of the coil 20. The variation in the inductance of said coil 20 is therefore representative of the user's pressure on the handle 10.

(35) The invention proposes to measure the variation in the inductance of the coil 20 in order to detect the user's pressure on the handle 10, and thus to validate his intention to unlock the vehicle.

(36) For this purpose, the control means 60 initially control the oscillation frequency of the oscillating circuit, using the frequency adjustment means M1.

(37) For example, the adjustment means M1 adjust the oscillation frequency of the oscillating circuit consisting of the coil 20 and the capacitance C1 to a level close to its resonance frequency, for example to a value of 80% of its resonance frequency.

(38) When the user presses on the locking area Z1 of the handle 10, the non-magnetic metal target 40 approaches the coil 20, as explained above, thereby modifying the oscillation frequency of the LC oscillating circuit.

(39) The measurement means M2 measure a number of oscillations of the oscillating circuit during predetermined time interval d, and deduce from this the actual oscillation frequency of the LC oscillating circuit consisting of the coil 20 and the capacitance C1. By measuring the actual frequency of said oscillating circuit, the measurement means M2 deduce from this the inductance L of the coil 20.

(40) $F=\frac{1}{2\sqrt{LC}}$
And therefore:

(41) $L=\frac{1}{C}{\left(\frac{1}{2F}\right)}^2$

(42) The comparison means M3 compare the inductance L measured in this way with a threshold inductance value L.sub.s representative of the user's pressure on the handle 10. If the measured inductance is below the threshold inductance value, that is to say L<Ls, then the user is pressing on the handle 10, and his intention of locking the vehicle is validated.

(43) It should be noted that other measurement strategies are possible; an equivalent resistance of the oscillating circuit may be measured and compared with a threshold value of equivalent resistance. In this case, if the measured value of the equivalent resistance is greater than the threshold value of equivalent resistance, then the user is pressing on the handle 10, and his intention of locking the vehicle is validated.

(44) Thus the detection device D according to the invention can be used to detect the intention to lock the vehicle, in a reliable manner and without the risk of false positives. This is because the inductive sensor, unlike the prior art capacitive sensor, is not sensitive to external disturbances.

(45) Moreover, the compressible prestressed element, the first part of the casing (which is elastically deformable), and the elastically deformable part of the handle enable the movement of the non-magnetic metal target relative to the coil to be extended without adversely affecting the aesthetic appearance or the ease of use of the handle.

(46) Advisably, the detection device D of the invention is designed to measure movements of the target which are very small (20 m to 100 m), but which are representative of the user's pressure on the locking area for locking his vehicle.