EP1513999A1

EP1513999A1 - Electronic control circuit comprising a transmitter for a vehicle door locking system

Info

Publication number: EP1513999A1
Application number: EP03753575A
Authority: EP
Inventors: Elio Mariotto; Rachid Dadi; Benedikt Othmar Scheller
Original assignee: Schaffner EMV AG
Current assignee: Schaffner EMV AG
Priority date: 2002-06-20
Filing date: 2003-06-20
Publication date: 2005-03-16
Also published as: AU2003271744A1; WO2004007879A1

Abstract

Disclosed is an electronic control circuit for a car door locking system, comprising at least one induction coil (3) which forwards a data request to an external contactless data carrier and causes the car door locking system to unlock when a valid response is received by said data carrier. The induction coil (3) is provided with a ferrite core and is disposed in a hollow space (72) of a handle (7) of the car door locking system. The control unit is protected by a multi-part watertight housing (1, 13).

Description

Electronic control circuit with a transmitter for a vehicle door

locking system

The present invention relates to an electronic control circuit for a vehicle door locking system. The present invention also relates to a vehicle door handle with a cavity in which an electronic control circuit is housed.

In such a car door locking system, a vehicle door locking system is unlocked by means of an electronic control circuit integrated in the vehicle door handle, that is, from a state that prevents opening of the door or flap to a state that enables opening of the door or flap ,

In the case of locking systems of the type mentioned above, it is already known to allow a person access to a vehicle by querying data from a contactless portable data carrier (for example in a chip card or in a key hanger). The data query is triggered by a mechanical switching element or by a proximity sensor, which triggers the forwarding of a data query to the external portable data carrier when a person approaches the handle. The data carrier (for example a transponder) is "woken up" by the received data query and answers it by sending an identification message to the locking system. The locking system only releases the door when the identification is valid.

In order to communicate with the external contactless data carrier, known electronic control circuits for vehicle door locking systems often comprise a transmitter or a transceiver with a resonance circuit which, for example, consists of the series connection of an induction coil with a capacitance. The induction coil generates an electromagnetic field that is received by the external data carrier. The desired range is typically around one and a half meters. To achieve this range at the desired frequency, an induction coil with a large inductance must be provided become. Such an inductance can only be achieved if the induction coil comprises the largest possible ferrite core.

To achieve this range, the induction coil must be installed outside the car body so that the electromagnetic field is not damped. The optimal position for mounting the induction coil is inside the car door handle, very close to the data carrier of an approaching person and to the other electronic and mechanical parts of the car door locking system. The induction coil or even the entire electronic circuit is sometimes cast into a polymeric mass, primarily to protect it from moisture.

For aerodynamic and design reasons, however, many car door handles are made very thin, so that the available thickness for the induction coil is limited. In this case, the ferrite core must be very thin and long. However, thin ferrite cores can break if the car door handle is handled roughly and if the housing around the control circuit is deformed. This risk must be reduced, because otherwise the driver could no longer get into his car.

In addition, the electronics of the control circuit are sensitive to water and dust and must therefore be protected against moisture infiltration. It is already known to mount electronic components in a car door handle and to subsequently make this handle watertight with synthetic seals (for example made from Santoprene or from another elastomer). However, the assembly of the handle with such seals is a process which has to be carried out manually and is therefore expensive. If an identical control circuit is determined for installation in different handles, the problem of water resistance must be solved anew for each handle. It has also been proposed to encapsulate the electronic components in a thermoplastic insulating material. Experiments were carried out with a "hot melt" material (for example Macromelt), which is sprayed at a temperature of approximately 215 ° degrees and at low pressure. This solution has proven to be efficient, but has the disadvantage that any bending stress on the unit loads the ferrite core of the induction coil by the casting compound. In addition, the elastic potting material offers little protection against impacts and does not contribute to achieving the necessary assembly rigidity. The protection of the induction coil is therefore primarily dependent on the metallic outer parts of the handle, which are designed differently for each vehicle. Patent application WO01 / 07736 describes a locking device for motor vehicles, in which the induction coil is mounted as a component on a printed circuit board and is protected against impacts by accommodating it in a base part. The induction coil is firmly mounted on the circuit board so that it could break if the circuit board or the housing is deformed.

Patent application WO01 / 07736 describes an outer door handle for vehicles in which the electronic components are protected by a U-shaped shell. However, such a shell is not watertight, so that the watertightness must be ensured by the handle.

It is therefore an object of the present invention to provide an electronic control circuit for a vehicle door locking system which comprises an induction coil with a ferrite core and which can be made as thin as possible.

Another object of the invention is to provide such an electronic control circuit in which the risk of the ferrite core breaking can be significantly reduced without increasing the manufacturing costs. According to the invention, these objectives are achieved by an electronic control circuit according to claim 1, preferred exemplary embodiments being specified in the dependent claims.

In particular, these objectives are achieved by an electronic control circuit for a car door locking system, in which a control unit with at least one induction coil is provided, the named induction coil being accommodated in a cavity in a handle of the named vehicle door locking system, and in which the Induction coil is protected by a multi-part closed housing in the cavity.

This has the significant advantage that the induction coil is efficiently protected from bumps, deflections of the car door handle, moisture and / or dirt by the housing. In addition, the watertightness can already be guaranteed when assembling the circuit and is not dependent on the installation in the vehicle door handle.

The ferrite rod is preferably only loosely attached in the housing, so that a certain mechanical play can absorb any deformation of the handle. In a preferred variant, it is attached to the housing by means of retaining clips. Retaining clips have the significant advantage that they can be manufactured cheaply and can even be part of a housing or a printed circuit board without increasing the manufacturing costs. In addition, they can have a spring effect, so that the ferrite core can move easily if the handle is deformed.

Preferred exemplary embodiments of the invention are described in more detail below with reference to the accompanying drawings. Show it:

Fig. 1 shows the handle of a pull handle and part of a vehicle door in cross section. Fig. 2 is a first variant of the control circuit shown in perspective.

Fig. 3 is a perspective variant of the second control circuit.

Fig. 4 is a schematic of the electronic control circuit.

1 shows a vehicle door pull handle, which comprises an inner part 9 fastened to the vehicle door and a handle 7 designed as a bow handle. The handle 7 comprises a handle dome 70 which, with the end facing away from the handle 7, projects into the interior 90 of the vehicle door and is connected to the car door locking system, which is not shown for reasons of clarity. The car door locking system is unlocked via the vehicle central locking system in order to free the handle dome 70 and thus the handle 7. In the released state, the handle 7 can be pulled outwards to open the vehicle door. For this purpose, the handle 7 can be rotated about the joint 71 shown. As a variant, the door could open automatically after recognition of a valid identification of the person requesting access.

In the handle 7 there is a cavity 72, in which the electronic control circuit 1 is accommodated, which is intended to enable the authorized user to trigger the unlocking of the car door locking system in the most convenient way possible. In the variant shown, the cavity is only accessible from that side through which the control circuit must be inserted during assembly. In a preferred variant, not shown, however, the cavity 72 is accessible from both longitudinal ends so that the control circuit is inserted from one side and a connector described later from the other side.

The control circuit 1 is connected to the car door locking system inside the vehicle by connecting cables 12. She will preferably powered by these connecting cables from the car battery. In the event of a power failure, the door can preferably be opened by means of a locking cylinder (not shown) with a key provided for such cases.

The control circuit includes a touch sensor 82 which is a

Signal is triggered as soon as the user places a finger (especially a thumb) on the outer side of the handle. A proximity sensor 5 triggers another signal when a hand or another earthed object approaches, particularly in the case of a hand approaching the space between the handle 7 and the inside of the handle 9. As explained later, these signals are from a control unit 20 interpreted with a microcontroller and at least one induction coil 3 in order to forward a data query to an external contactless data carrier, not shown.

The data carrier preferably consists of a transponder

(which can be integrated, for example, into a chip card or into a key ring) and is "awakened" by this data query. If the data query is addressed to him, he responds with a response which includes an identification of the data carrier or which is signed with such an identification. The response is received by the locking system in order to trigger the unlocking of the car door locking system if it contains the expected identification or if it was signed with this expected identification.

A first variant of the control circuit 1 is described in more detail in connection with FIGS. 2 and 4. It comprises a large number of electronic components which are mounted on a thin, flexible printed circuit board 2 in a synthetic insulating housing 1, 13 and which are electrically connected by electrical connecting means, not shown. The housing 1 longitudinally fills most of the cavity 72 in the handle 7. According to the invention, the housing consists of two parts 1 and 13, which are ultrasonically welded or glued to one another after assembly. The lower part 1 is a cover which has holding clamps 10, 11, lugs 51, ribs 212, 50 and recesses 40 in order to position and / or hold various components of the control circuit, as described later. The upper part 13 is a floor which is reinforced with reinforcing ribs. It is also possible to provide the base 13 with positioning means (not shown) in order to hold certain components (including the easily bendable proximity sensor electrodes 5 described later) on both sides. If the thickness of the cavity allows, it is also possible to provide the cover 1 with reinforcing ribs. A glass-reinforced polymer is preferably used as the material for the housing.

During assembly, all electronic components are temporarily placed on the cover 1 and positioned or fastened by the holding means 10, 11, 212, 40, 50, 51. A printed circuit board described later is mounted upside down over the lid, in such a way that electrical soldered connections to be tested are accessible as long as the base 13 is not mounted. Electrical and optical tests can then be carried out. In these tests, the winding of the induction coil 3 and the soldered connections of the capacitor 4, the shielding strips 21, the proximity sensor electrodes 5 and the connecting cable 12 can be tested in particular.

After these tests, the bottom is placed over the lid 1 and aligned and temporarily fixed by cooperating lugs 18 and holes 130. A rubber seal, not shown, can be provided, in particular to seal the entry of the cable 12. Both housing parts are then glued together or preferably welded with ultrasound.

The control circuit 1 comprises a contactless transmitter in order

Exchange data with the external contactless data carrier. In the preferred variant shown, the contactless transmitter comprises one Resonance circuit with an induction coil 3 and a capacitor 4, which are mounted directly on the cover 1 in the variant shown. The induction coil consists, for example, of a winding of an electrically insulated wire on a plate-shaped ferromagnetic ferrite core. In order to achieve the required inductance, the length of the ferrite core is greater than 40 mm. However, its thickness must be less than 4 mm so that it can be installed in a car door handle. In a preferred variant, the profile of the ferrite core is X-shaped. Those skilled in the art will understand that instead of a ferrite core, another soft magnetic core (for example made of an amorphous material or a laminated core) could also be used in an equivalent manner. Accordingly, "ferrite core" is used in this description and in the claims as a general term for all soft magnetic induction coil cores.

The induction coil 3 is fastened to the cover 1 by a plurality of holding clamps 10, 11. Four first nose-shaped holding jaws 11 hold the lateral flanks of the induction coil 3 in order to restrict both their lateral and their vertical freedom of movement. Four second holding clamps are also preferably used in order to restrict the longitudinal freedom of movement of the induction coil 3. The first and second holding clamps are designed in such a way that the induction coil 3 can move more along its longitudinal axis than along the other two axes. The core can preferably be displaced along its longitudinal axis by at least one millimeter or as part of the deflection. This freedom of movement is made possible both by the play between the core and the second clamps and by the elasticity of the second holding clamps. Since the induction coil 3 is only loosely attached by the second retaining clips 10, the housing 1 can be deformed or bent without stressing or even breaking the ferrite core and without exerting pressure on the electrical contacts. The play between the ferrite core and the holding clamps 10 and the resilient effect of the second holding clamps also allow the induction coil to be assembled more easily, which is simply clicked into place. As a variant, one could completely focus on the second in an embodiment not shown Dispense with retaining clips 10. The ferrite core does not touch the upper inside of the cavity so that the housing can absorb a certain amount of deflection without stressing the ferrite core.

In the example shown, the first holding clamps 10, 11 are part of the synthetic cover 1. It would also be possible (although possibly more expensive) to mount synthetic or metal holding clamps on the cover 1, or to fix the ferrite core to the bottom 13. For example, the first and / or second retaining clips could be mounted and held through openings in the housing 1. If conductor tracks are provided on the inside of the housing 1, metal retaining clips can also be mounted on these conductor tracks, for example as SMD components. The induction coil could also be attached to the printed circuit board 2 (preferably with additional holding clamps).

In this embodiment variant, the cavity 72 inside the handle is preferably not filled with potting compound. The induction coil is thus held only by the holding clamps 10, 11. The seal is made through the housing 1, in which seals, not shown, can be provided. In order to dampen vibrations, a gel (for example a silicone gel) can be poured into the housing.

The capacitance of the resonance circuit is preferably one

Ceramic or polypropylene capacitor with a value of approx. 1 5 to 18nF. It is used to match the impedance of the induction coil to the driver stage of the microcontroller. It is preferably positioned and / or fastened in the cover by further ribs 40.

An SMD control unit 20 built around a microcontroller (not shown) can be mounted on the left underside of the printed circuit board 2. It is connected to the induction coil 3 via connecting cables, not shown, and / or via conductor tracks, not shown. The control circuit 1 also comprises a proximity sensor with (in this preferred example) two proximity sensor electrodes 5 in order to sense people who are approaching the handle. The proximity sensor electrodes 5 are electrically connected to the control unit 20 in such a way that the capacitance changes caused by the user body between the proximity sensor electrodes 5 and the earth are sensed. If a (grounded) person approaches the proximity sensor electrodes 5, the capacitance between these electrodes and the earth is impaired. The control unit 20 preferably determines these small changes in capacity using a charge transfer measuring system, ie by switching the unknown capacity with a larger reference capacity via switches.

In the embodiment variant shown, the proximity sensor electrodes 5 consist of two curved strips which are positioned and held by two pairs of cooperating ribs 50 in the cover 1 and in the base 13. One end 50 of each electrode 5 is soldered into a recess 27 through the printed circuit board or fastened with conductive adhesive, so that they cannot be unsoldered by longitudinal forces caused by bending of the housing.

An electrostatic shield held by further ribs 212 is provided between each proximity sensor electrode 5 and the induction coil 3. This shielding prevents, inter alia, that the measurement of the capacitance between the proximity sensor electrodes and the earth is disturbed by the induction coil 3 and that parasitic charges reach the sensitive proximity sensor electrodes 5. According to the invention, the shield 21 consists of two strips made from one part and connected to one another by a bridge 210. The bridge 210 is soldered to the upper accessible side of the circuit board 2 at two points 25; two further soldering feet 211 are soldered onto further soldering points 26 of the printed circuit board 2 and electrically connected to the earth. In this way, the shielding strips are positioned precisely and additionally increase the flexural rigidity of the assembly. In a preferred variant, the shielding strips 21 are glued to the points 25, 26 instead of soldered with an electrically conductive adhesive in order to better control the overall thickness. The touch sensor already mentioned consists of the largest possible capacitance 22 with an electrode on each side of the circuit board. The distance between the two electrodes can be increased by an additional printed circuit board 20.

The printed circuit board is connected to the electronics inside the vehicle via connecting cables 12, which in this variant are soldered directly into openings through the printed circuit board 2 or by the so-called auto-splice method. These cables go through the housing 1, 13; a rubber seal is preferably provided to make the housing watertight.

Dispensing with potting in the housing 1, 13 permits longitudinal play of the various components, in particular the induction coil, when the housing bends, so that the electrical contacts and the ferrite core do not have to absorb any pressure.

FIG. 3 shows a second embodiment variant of the control circuit, in which the connecting cables 12 are connected to the printed circuit board 2 via a plug 122-123. The plug 122 also creates the watertightness of the housing 1, 13. This variant has the advantage that the housing 1, 13 can be inserted from one side and the plug from the opposite side in a handle with two openings on both sides of the cavity 72. It is therefore not necessary to pull the connecting cable 12 through the cavity.

Although the entire description relates to a vehicle pull handle, it will be understood that this invention is also applicable to other types of vehicle door exterior handles, particularly handle flaps or antennas within the vehicle or in the trunk area. For some applications, the control unit in the housing can only consist of the induction coil. In this case, the ferrite core could also have a greater thickness, for example up to 8 mm, in order to achieve better efficiency.

Claims

Expectations

1. Electronic control circuit for a vehicle door locking system, comprising: a control unit (20) with at least one induction coil (3), the named induction coil (3) in a cavity (72) in a handle (7) of the named vehicle door Locking system is housed, characterized in that the named induction coil in the said cavity is protected by a multi-part housing (1, 13).

2. Electronic control circuit according to claim 1, in which said control unit (20) is protected by said housing (1, 13).

3. Electronic control circuit according to claim 2, in which said housing is provided as a waterproof component that can be retrofitted in said vehicle door handle.

4. Electronic control circuit according to claim 2, in which at least a named part of said housing (1, 13) is provided with retaining clips, lugs and / or ribs in order to hold said induction coil (3).

5. Electronic control circuit according to one of claims 1 to 4, in which an elastic material, for example a gel, is provided in said housing (1, 13) to dampen vibrations of said induction coil (3).

6. Electronic control circuit according to one of claims 1 to 5, in which at least a named part of said housing (1, 13) is provided with reinforcing ribs (131).

7. Electronic control circuit according to one of claims 1 to 6, in which said parts of said housing (1, 13) are fixed together via cooperating lugs (18) and holes (130).

8. Electronic control circuit according to one of claims 1 to 7, in which said parts of said housing (1, 13) with

Ultrasonically welded to one another in such a way that the named housing is watertight.

9. Electronic control circuit according to one of claims 1 to 7, in which said parts of said housing (1, 13) are glued together in such a way that said housing is watertight.

10. Electronic control circuit according to one of claims 1 to 9, in which an intermediate space is provided between said induction coil and at least one named part of said housing, such that said housing (1, 13) can be bent without the induction coil ( 3) bend.

1 1. Electronic control circuit according to one of claims 1 to 10, in which said induction coil is held in said housing such that it can move longitudinally, so that said housing (1, 13) can be deflected without the inductor bend coil (3).

12. Electronic control circuit according to one of claims 1 to 11, in which said housing (1, 13) remains without potting.

13. Electronic control circuit according to one of claims 1 to 12, in which the length of said induction coil is greater than 40 mm and the thickness of said induction coil is less than 4 mm.

14. Electronic control circuit according to one of claims 1 to 13, with a proximity sensor with at least one proximity sensor electrode (5) to forward the named data query to trigger when a person approaches the said proximity sensor electrode, said proximity sensor electrodes being fastened to the inside of said housing (1, 13) by further ribs (50).

15. Electronic control circuit according to claim 14, in which said proximity sensor electrodes are soldered in recesses (27) in a circuit board (2).

16. Electronic control circuit according to one of claims 14 to 15, wherein an electrostatic shield is provided between each said proximity sensor electrode (5) and said induction coil (3), said shield consisting of two strips made of one part and connected together.

17. Electronic control circuit according to one of claims 1 to 16, in which said control unit (20) and said induction coil are mounted on a printed circuit board (2).

18. Electronic control circuit according to claim 17, in which the upper side of said printed circuit board (2) is covered by a cover part (1) of said housing and in which the lower side of said printed circuit board (2) by a bottom part (1) of said Housing is covered, and in which the named cover part and the named bottom part are both made of plastic.

19. Electronic control circuit according to one of claims 17 to 18, in which said housing comprises a first part (1) which, via holding means (10, 11, 212, 52), for holding and / or positioning said induction coil (3) and said printed circuit board (2), said printed circuit board being mounted over said first part (1) such that the electrical solder connections are accessible as long as the other part (13) of the housing is not mounted.

20. Electronic control circuit according to one of claims 1 to 19, with a plug (122) through said housing to connect connecting cables (12) for connection to the vehicle door locking system inside the vehicle.

21. A manufacturing method for an electronic control circuit for a vehicle door locking system, comprising the following steps:

Placing a control unit (20) with at least one induction coil (3) and a printed circuit board (2) on a cover (1) in such a way that electrical soldered connections to be tested are accessible, electrical and / or optical tests of the soldered connections,

Laying a bottom (13) over the named cover (1), the named induction coil (3) being protected by the named cover and by the named bottom.

22. A manufacturing method according to claim 21, in which said lid and bottom form a housing which is sealed.