FR2732284A1 - Auxiliary control unit e.g. for different motor vehicle functions such as car lights or windscreen wipers - Google Patents

Abstract

The control device generates signal functions (1,2) with individual voltage signals using an ASIC generator (14,15). The signals are passed to a microprocessor (13). A processing stage (GP) takes the signals and applies a protocol, so that they can be passed across a two wire interface (10,11) to the command unit (7). The command voltages are generated by resistance variations.

Description

 The present invention relates to a device for controlling various functions in a motor vehicle comprising a control member fixed relative to the steering wheel.

 Control devices comprising control elements around the steering wheel traditionally comprise one or more switching members intended to transmit instructions to different elements of the vehicle, for example for controlling the lighting, wiping, washing, demisting, etc.

 FIG. 1 illustrates an example of a conventional organization of different switching members 1 to 4 around a steering wheel 5. Switch 1 controls the lighting and signaling of the vehicle. Switch 2 is commonly assigned to the wiping and washing commands for the windshield and the rear window. The additional switch 3 is assigned to related functions, such as remote controls for the car radio.

 The bodies referenced by 4 are those which are placed in the steering wheel 5 (audible warning for example).

The steering wheel 5 must of course be free to be able to make one or more turns on its axis. To this end, the electrical connection between the members 4 placed in the steering wheel 5 and the elements which they control is traditionally carried out by means of rotary contactors 6.

 Generally, in particular when the number of members 4 is low, such a rotary switch 6 is made up of tracks and associated complementary sliders - some integral with the steering wheel 5, the others fixed inside the vehicle body - ensuring contact rubbing on 3600 and on several turns of the flywheel.

 The introduction on modern vehicles of airbags ("airbag" according to the English terminology commonly used) has modified the technology of these rotary switches. ÉJ'.izents, such as the sliders, which may cause micro-cuts on the cushions are indeed prohibited. Now generally used to make the electrical connection of the control members integrated into the steering wheel, a sheet wound over several turns in a housing placed annularly around the steering column.

 The two ends of the ply are connected respectively to a fixed point placed in the passenger compartment and to a point inside the steering wheel 5 and integral with it.

 The annular housing placed around the column makes it possible to maintain and guide the coiled turns of the sheet when the handwheel turns, so that they wind and unroll without difficulty e 5GiI interior and thus ensure a reliable electrical connection between the two points above.

 Of course, it is already known to integrate into the steering wheel 5 other control members than that of the horn.

 An organization in this sense has been illustrated in FIG. 2. The related switch has been referenced there by 7 and is arranged inside or at the periphery of the steering wheel 5 while being integral with the latter.

 The advantage of control devices of the type of switch 7 placed in the steering wheel is that they allow so-called comfort controls: the driver does not have to search for them; nor does he have to let go of the steering wheel to activate them.

 This is why these control members 7 are assigned to functions such as the controls of the radio, the controls of the speed regulation device, the controls for adjusting the air conditioning, etc. Such a control member 7 can be dedicated to a particular function or, on the contrary, be a control member common to several functions.

 In this second case, we speak of a general-purpose switch. Such a member 7 is then actuated according to a menu in which the user can enter to perform a particular function.

 For example, the same control member 7 makes it possible to increase or decrease the volume of the radio, or to increase or decrease the ventilation of the air conditioning device, to decrease or increase the set speed of the regulation device speed, etc.

 Conventionally, such a versatile control member 7 is used between the various elements and the tool controlling a multiplexed link architecture of the type illustrated in FIG. 3.

 With such an architecture, the instructions provided by the operator to the control member 7 are transmitted to a four-way multiplexing bus 9 via four connecting wires 8 connecting the control member 7 to the rotary switch 6. The four channels are divided into a positive supply link, a ground connection and one or two data channels. The control member 7 is for this purpose associated with a multiplexing unit M, comprising in particular a protocol management unit GP and means D of interface for the data.

 The controls associated with each of the cozmeçateurs (light switch 1, wiping and washing switch 2, etc.) placed on each side of the steering wheel 5 can also be multiplexed, these different switches also being associated with multiplexing units Mr.

 However, this configuration, if it is very flexible, requires that the rotary switch makes a connection with at least four channels. It also requires at least three separate multiplexing electronics.

It is therefore very expensive.

 The invention provides a solution which overcomes these drawbacks.

 More particularly, the invention provides a device for controlling different functions in a motor vehicle comprising at least one control member fixed relative to the steering wheel and at least one control member which is located in the vicinity of the steering wheel, for example below of the latter, and which is substantially fixed relative to the passenger compartment, the instructions generated by the actuation of these members being transmitted to the various elements corresponding to the functions controlled by means of a coded serial link, the member control unit fixed with respect to the steering wheel being connected to said coded serial link via a protocol management unit and a rotary contactor disposed around the steering wheel column, characterized in that the management unit protocol is fixed relative to the passenger compartment of the vehicle and is connected to the control unit fixed relative to the steering wheel via a two-wire connection passing through the rotary contactor, this control member comprising means for transmitting at the input of said two-wire connection control voltages corresponding to its actuation, the protocol management unit being connected to means for receiving these control voltages at the output of the two-wire connection, these receiving means also receiving control voltages from the control member in the vicinity of the steering wheel.

Other characteristics and advantages will emerge from the description which follows. This description is purely illustrative and not limiting. It should be read in conjunction with the accompanying drawings on which
FIG. 1 and FIG. 2, already analyzed, illustrate two known types of organization for control members around a steering wheel of a motor vehicle
Figure 3, also already analyzed, is a schematic representation illustrating an already known architecture ensuring a multiplexed connection between the control members of the organization of Figure 2 and the various elements of the motor vehicle they control
Figure 4 is a figure similar to Figure 2 for a device according to an embodiment of the invention
Figure 5 is a diagram of a possible electrical assembly for the architecture of the two-wire connection of Figure 4
FIGS. 6a and 6b represent sequences of pulses implemented with the assembly of FIG. 5
Figure 7 is a diagram of an electrical assembly associated with a control member disposed under the steering wheel of the device illustrated in Figure 4
Figure 8 illustrates the mechanical layout of the various elements of the architecture of Figure 4
Figure 9 is a sectional view along the line
Figure IX-IX
FIG. 10 is a schematic top view illustrating the shape of the printed circuit of the architecture of FIG. 8.

 The control device illustrated in FIG. 4 has only one multiplexing station M.

 This station M is not integral with the steering wheel 5, but is an external station fixed relative to the passenger compartment of the vehicle.

 A two-wire connection 10 ensures the transfer of information between the control member 7 fixed relative to the steering wheel and this external multiplexing station M, through a rotary switch 11.

 To this end, the control member 7 placed in the steering wheel 5 is associated with transmission electronics 12 which sends voltage-coded signals to a microprocessor 13 of the unit M, via the two-wire connection 10 .

 The microprocessor 13 is itself connected to a protocol manager GP which interfaces with the bus 9.

 This microprocessor 13 also receives voltage signals sent to it by electronics 14 and 15 associated with the other control members arranged around the steering wheel, and in particular to the switch 1 for lighting control and to the switch 2 for wiper control.

 Advantageously, these electronics 14, 15 are constituted by circuits of the variable resistance type. Such circuits will be described later in more detail with reference to FIG. 7.

 Advantageously also, the control device may comprise, in addition to the elements illustrated in FIG. 4, means (not shown) for controlling the various possible movements for the steering column: longitudinal movement of advance or retreat, height adjustment ( rise or fall of the column). The control members provided for this purpose are then also associated with electronics, the voltage outputs of which are sent to analog / digital converters at the input of the microprocessor 13.

 In Figure 5, there is shown a particular assembly corresponding to circuits of the unit 12 and the microprocessor 13 for the transfer of information between the control member 7 secured to the steering wheel 5 and the various elements of the motor vehicle that it ordered.

 In this arrangement, the unit 12 associated with the control member 7 is a unit for both transmitting and receiving.

 It comprises an integrated circuit 14 of the ASIC type for the transmission and reception of coded voltage signals. This ASIC circuit 14 is connected to the outputs of switches referenced by 16 as a whole, which are switched from the control member 7 and whose states control the various functions controlled by said member 7.

 One of the outputs of this ASIC i4 circuit is connected to the base of an emission transistor 15, whose emitter is connected to ground and whose collector is connected to one end of a resistor 17. L ' another end of this resistor 17 is connected to one, referenced by 10a, of the two wires of the link 10 passing through the rotary switch 11.

 At its other end, this wire 10a is itself connected, at the input of the microprocessor 13, on the one hand, to a DC voltage supply source + Vc via a resistor 18 and, on the other hand part, to one of the inputs of an operational amplifier 19, via a resistor 20. The other input of this amplifier 19 is connected to a first resistor 21 itself connected to ground, as well as 'to a second resistor 22 which is itself connected to the supply voltage source + Vc.

 As will be understood, the other wire of the connection 10 is connected to ground.

Furthermore, the output of the collector of transistor 15 is connected to the anode of a diode z4 whose cathode is connected to a power supply input of the circuit.
ASIC 14.

 The cathode of diode 24 is also connected to ground via a capacitor 25 mounted in parallel with a Zener diode 26.

 Thus, the ASIC circuit 14 is supplied with voltage by the voltage source + Vc, which also supplies the microprocessor 13, through the two resistors 17 and 18 and the diode 24. The capacitor 25, the voltage of which is regulated by the diode zener 26 maintains the desired supply voltage at the input of the ASIC circuit 14.

 Also, the ASIC circuit 14 is connected to one end of a capacitor 23, the other end of which is grounded. This capacitor 23 supplies the ASIC circuit 14 with the reference oscillation. Of course, other solutions can be used (resonator circuit or crystal oscillator for example).

With such an assembly, when the output of the circuit
ASIC 14 sends a transmission signal to transistor 15, the potential at the output of resistor 17 drops below a threshold imposed by the two resistors 21 and 22 and is detected by the comparator that constitutes the operational amplifier 19.

 When the ASIC circuit 14 does not transmit, it is understood that it is possible to use the unit that constitutes the circuit 13 to control elements located in the vicinity of the steering wheel or fixed relative to the latter as a function of information. transmitted by the cod6 serial link that constitutes the bus 9. In particular, the unit 13 can transmit, via the two-wire link 10, control voltages to one or more elements integrated into the fixed control member 7 with respect to the steering wheel, these elements being for example information display elements intended for the driver of the vehicle.

 For this purpose, on the assembly shown in Figure 5, there is provided an emission circuit 27 controlling the base of a transistor 28, whose emitter is connected to ground and whose collector is connected to one end d 'a resistor 29, the other end of which is connected to the node N, between the resistors 18 and 20, to which the line 10a is connected.

A resistor 30 connects the end of the resistor 17 which is also connected to the diode 24 and to the transistor 15, to an input 31 presented by the circuit
ASIC 14 for receiving a signal from microprocessor 13.

 This input 31 is further protected against overvoltages by means 32 comprising a capacitor and a zener diode connected in parallel to the ground.

 The ASIC circuit 14 includes reception means similar to those at the input of the microprocessor 13 to detect the modulation controlled by the transistor 28.

Light emitting diodes 33 are connected in series with Col limiting resistors; -? - t 34 between the cathode of diode 24 and the circuit outputs
ASIC 14. These outputs are controlled by said circuit
ASIC 14 according to the messages that its input 31 receives so as to switch on or off these diodes 33 which thus serve as indicator light.

 FIG. 6a gives an example of a signal S1 emitted by the ASIC circuit 14 in the direction of the comparator 19.

 This signal S1 is broken down into a plurality of successive elementary signals Sla, Slb, etc., each of duration equal to a period of a reference signal. Each of these elementary signals Sla, Slb, etc. carries binary information 0 or 1 which corresponds to the state of one of the switches 16 controlled by the control member 7 secured to the steering wheel.

 For example, the elementary signal Sla corresponds to the switch 16a, the elementary signal Slb to the switch 16b, the elementary signal Slc to the switch 16c.

In FIG. 1, the signals Sla and Slb are in logic state 1, the signal Slc being in logic state 0.

 Each transmitted signal S1 is followed by a significant duration T without emission, that is to say during which the transistor 15 is not controlled.

 After having detected a time period T1 without emission, the microprocessor 13 can in turn transmit towards the circuit 14.

 When this transmission in the opposite direction is finished, the circuit 14 transmits again when it has detected a sufficiently long time T2 without signal.

 In FIG. 6b, the variation over time of the voltage signal S at the node N is illustrated, this signal corresponding to the superposition of the signals emitted respectively at the output of transistor 15 and of transistor 28.

is chosen to be low compared to the capacity provided by the capacitor 25 and the Zener diode 26, so that, during a transmission sequence, the supply voltage of the ASIC circuit 27 remains approximately constant.

 FIG. 7 illustrates a possible embodiment of a circuit with variable resistances which can be used to constitute one of the control circuits 14 and 15.

 The circuit more particularly illustrated in this FIG. 7 corresponds to a circuit associated with a wiper switch (control member 2 in FIG. 4).

 This circuit comprises a resistor 35 at one end is supplied at voltage + Vc by the microcontroller 13. The other end of this resistor 35 is connected to a sub-circuit which comprises, on the one hand, a resistor 36, the voltage V is sent to the input of the microcontroller 13, and, on the other hand, a plurality of resistors, referenced from R1 to R5.

 A switch I1 for wiper control with several positions consists of contact pads associated with the angular position of switch 2 to short-circuit these different resistances according to the type of operation desired for the wiper (s). ).

 In its rest position illustrated in FIG. 7 (wipers stopped), the switch It does not short-circuit any of the resistors R1 to R5. Resistor 36 is then mounted in parallel with these resistors R1 to R5 in series.

When the switch 2 is in its position corresponding to the command in low speed of the wipers, the switch I1 is toggled in a position where it short-circuits the resistors R4 and R5. Resistor 36 is then mounted in parallel with resistors R1 to
R3 in series. The voltage recorded across the resistor 36 is therefore different from that noted in the case where the switch I1 is in its position illustrated in FIG. 7 corresponding to the stop wiper control.

 The switch I1 can also be toggled to two other positions, corresponding to the control of the operating state at high speed or intermittently.

 Also, another switch I2 controlled independently with respect to the switch I1 is provided for shorting the resistors R2 to pr. This switch I2 controls the operation in washing mode.

 Reference is now made to FIGS. 8 to 10 in which an example of a mechanical arrangement has been illustrated for the various elements of the architectures illustrated in FIGS. 4 and following.

 The steering column was referenced by C.

 A support piece P is crossed by said column C and carries the members 1 and 2 for lighting and wiping control.

A housing 39 is formed in this support piece
P to receive the printed circuit 40 which corresponds to the microprocessor 13. This circuit 40 is protected by a cover forming a receptacle.

 The control members 1 and 2, on the one hand and the printed circuit 40, on the other hand, have complementary connection means 37, 38 such that the connection between the switches 1 and 2 and the microprocessor 13 is carried out directly by construction, without intermediate wire connection.

 In its lower part, the support part P is shaped so as to allow the connection of the printed circuit 40 with a power source of the vehicle (connection means 43).

 The upper part of the support piece P positions and receives the rotary switch '1; two-wire winding tape.

 Advantageously, the rotary contactor 11 has connection means 41 intended to cooperate with complementary connection means 42 carried by the printed circuit 40. The contactor 11 also carries connection means 44 intended to cooperate with complementary connection means (not shown) that has the control member 7 intended to be fixed on the steering wheel.

 A possible advantageous shape for the printed circuit 40 has been illustrated in FIG. 10. The circuit 40 has the form of a ring extended by two diametrically opposite ears of rectangular shape. It is crossed in its center by the steering column C. he circuit 40 can also be a half-ring extended by two ears.

 As a variant, the circuit 40 could be arranged parallel to the axis of the column. It is then advantageously made up of two parts placed on each side of the column and connected by a flat cable or a flexible circuit for example.

Claims (10)

 1. Device for controlling different functions in a motor vehicle comprising at least one control member (7) fixed relative to the steering wheel and at least one control member (1, 2) which is located in the vicinity of the steering wheel, for example below c ~ ;; - and which is substantially fixed relative to the passenger compartment, the instructions generated by the actuation of these members (1, 2, 7) being transmitted to the various elements corresponding to the functions controlled by the 'via a coded serial link (9), the control member (7) fixed relative to the steering wheel being connected to said coded serial link via a protocol management unit and a rotary switch arranged around the steering wheel column, characterized in that the protocol management unit (GP) is fixed relative to the passenger compartment of the vehicle and is connected to the control member (7) fixed relative to the flying via a two-wire connection (10) passing through the rotating contact, this control member (7) comprising means (12) for transmitting, at the input of said two-wire connection (10), control voltages corresponding to its actuation, the protocol management unit (GP) being connected to means (13) for receiving these control voltages at the output of the two-wire connection (10), these reception means (13) also receiving control voltages from the control member (1, 2) in the vicinity of the steering wheel.  2. Device according to claim 1, characterized in that the control member (1, 2) in the vicinity of the steering wheel comprises means of the resistance variation type (Figure 7) which generate said control voltages according to the actuation of said control member in the vicinity of the steering wheel (1, 2).  3. Device according to one of claims 1 or 2, characterized in that it comprises several such organs (1, 2) for control in the vicinity of the steering wheel, the receiving mys (13) connected to the management unit of protocol (GP) receiving control voltages from each of these different organs.  4. Device according to one of the preceding claims, characterized in that the reception means (13) connected to the protocol management unit (GP) comprise a unit capable of controlling elements (33) located in the vicinity of the steering wheel or fixed with respect to it as a function of information transmitted by the coded serial link (9).  5. Device according to claim 4, characterized in that said unit transmits via the two-wire connection (10) control voltages to one or more elements (33) integrated in I control member (7) fixed by with respect to the steering wheel, these elements being elements for displaying information intended for the driver of the vehicle.  6. Device according to one of claims 4 and 5, characterized in that said unit (13) controls the electrical adjustment of the steering column.  7. Device according to one of the preceding claims, characterized in that the receiving means (13) are integrated into an electronic circuit (40) of the integrated circuit type disposed in a housing (39) that has a part (P) forming support for the control member (1, 2) in the vicinity of the steering wheel, said electronic circuit (40) and said control member (1, 2) comprising complementary connection means (37, 38) allowing their electrical connection without connection wired intermediate.  8. Device according to claim 7, characterized in that the rotary contactor (11) is supported by said part (P) forming a support, said electronic circuit (40) and said rotary contactor (11) having complementary connection means (41 , 42) allowing their electrical connection without intermediate wire connection.  9. Device according to claim 8, characterized in that the rotary switch (11) and the control member (7) fixed relative to the steering wheel have complementary connection means (44, and not shown for the control member 7) allowing their electrical connection without intermediate wired connection.  10. Device according to one of claims 7 to 9, characterized in that the electronic circuit (40) consists of an integrated circuit on a monobloc substrate having an annular shape extended by two diametrically opposite ears and crossed by the steering column (C) (Figure 10).