EP1402547B1 - Low-current starter switch for vehicles and starter gear comprising said switch - Google Patents

Abstract

A low-current starter switch ( 1 ) for vehicles, includes a rotor ( 3;3 ') fixed to an anti-theft cylinder and an electrical circuit. The electrical circuit is low current with a variable resistance, depending on the annular position of the rotor ( 3;3 '), and provides an output voltage (V<SUB>x</SUB>) which varies as a function of the resistance.

Description

The present invention relates to a low-current starter switch for vehicles, of the type comprising a rotor, integral in rotation with the cylinder of the antitheft device, as well as an electric circuit.

The invention also relates to a starting equipment for vehicles, comprising said start switch.

STATE OF THE ART

The start switches are usually high power switches, i.e. they have contact elements and conductive tracks arranged to allow direct opening and closing of the electrical contact between the battery and the starter motor, accessories, etc., in each angular position of the switch rotor.

We have also developed switches, similar in configuration to the previous switches, which, instead of opening and closing directly the contact between the battery and the blocks to activate, connect or disconnect corresponding relays, each of which is associated to a block.

Known switches have significant disadvantages.

The main problems are due to the use of a power switch: in the first place, the switch is a costly and energy-demanding part, and requires sophisticated materials and design. In all cases, the quality of the electrical contact should be ensured in the face of problems related to friction, wear, free dielectric particles, oil and the like; and this, with high power contacts, especially in the case of the starter, whose consumption is very high. Another problem is that the switch is not a standard part, so each application requires a separate design, resulting in higher development and manufacturing costs.

In addition, the described systems require significant lengths of power cables, especially in the absence of relays; this increases the cost of all and causes space problems, because of the significant diameter of these cables.

US 6122 944 discloses a low current automotive switch.

DESCRIPTION OF THE INVENTION

The object of the present invention is to overcome the disadvantages of the technical state by developing a versatile low current start switch which is not subject to sophisticated design and construction requirements.

In accordance with this object, the start switch of the present invention is characterized in that said electrical circuit and consists of two potentiometers, both associated with the rotational movement of the rotor, which deliver independent output voltages; in this way, it is possible to detect the failures of one of the components by simply comparing the signals of the two potentiometers.

The invention also relates to a starting equipment for vehicles, comprising a start switch, characterized in that said start switch is of the type defined above and in that it comprises in in addition to a control circuit connected on one side to the output of the variable resistor electrical circuit of the switch and, on the other side, to at least two relays, said control circuit activating each of the relays as a function of the output voltage of the variable resistance electrical circuit.

The equipment is, on the whole, much less expensive and is subject to fewer requirements than traditional power switches, and also allows a significant saving of power cable, with a corresponding reduction in the cost of the equipment. and the space he occupies in the vehicle.

For different powers, it will be enough to change the relays, which are standard components at low cost; the same applies to the variations of the operating parameters for starting the vehicle, since it will suffice in this case to change the electronic components of the control circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

To better understand what has been exposed, drawings are enclosed in which there is shown schematically a practical case of embodiment only by way of non-limiting example.

• la figure 1 est une vue en perspective et éclatée d'un interrupteur de démarrage selon un premier mode de réalisation de l'invention ;
• la figure 2 est un schéma de connexion d'un système de démarrage incorporant un interrupteur selon l'invention ;
• la figure 3 est une vue analogue à la figure 1 montrant un interrupteur selon un deuxième mode de réalisation de l'invention ; et
• la figure 4 est un schéma de connexion des résistances et autres éléments de l'interrupteur de la figure 3.

In these drawings,

• Figure 1 is an exploded perspective view of a start switch according to a first embodiment of the invention;
• Figure 2 is a connection diagram of a starter system incorporating a switch according to the invention;
• Figure 3 is a view similar to Figure 1 showing a switch according to a second embodiment of the invention; and
• FIG. 4 is a connection diagram of the resistors and other elements of the switch of FIG.

DESCRIPTION OF PREFERRED EMBODIMENTS

A starter switch 1 according to the invention, as shown in the exploded view of FIG. 1, comprises a housing housing the components of the switch 1 and formed of two parts 2a and 2b that mate by means of a control system. elastic lozenges.

Inside the housing 2a, 2b, is disposed a rotor 3, one end of which is accessible from the outside through an opening 4 in the portion 2a of the housing. This end of the rotor accessible from the outside of the housing has a shape, not visible in Figure 1, adapted to the coupling with the end of the cylinder of the vehicle lock (not shown); in this way, when the user turns the key in the lock, the rotational movement is transmitted to the rotor 3.

The switch is permanently mounted in the steering column of the vehicle so that the axis of the rotor 3 is aligned with the axis of the lock.

In the embodiment shown in FIG. 1, the switch 1 further comprises two rotary potentiometers 5 and 6, of known type, housed inside the part 2b of the housing and whose connecting lugs 7 and 8, respectively, are accessible from outside the housing through an opening 9 formed therein.

The rotor 3 comprises an actuating axis 10, of non-rounded section, adapted to rotate the potentiometers 5 and 6 by interlocking form with an orifice 11 thereof.

Potentiometers 5 and 6 are of the type providing a stepped voltage: in other words, the output voltage does not increase linearly with the rotation angle, but has a series of different discrete values, each of which is constant over a range of rotation angles.

As illustrated in the connection diagram of FIG. 2, the switch 1 connects to a control circuit 20 via the tabs 7 and 8 of the potentiometers 5 and 6.

The control circuit 20 is responsible for reading the voltage supplied by the potentiometers at each instant, and, according to this voltage, for controlling the activation of relays 21, 22 connected to the battery 23: in this embodiment, for example, the relay 21 is responsible for putting the electrical equipment "on" 24, for example the power windows, air conditioning, radio, etc. ; the relay 22, for its part, activates the starter 25.

Relays 21, 22 are located near the elements they must activate; the amount of power cable (indicated in bold line in Figure 2) required for installation is therefore minimal. The rest of the cables (shown in fine lines) are signal transmission and can therefore be much finer.

In the embodiment shown, it has been planned to incorporate two identical potentiometers 5 and 6 in order to reinforce the safety of the assembly and to allow its verification: the readings of the two potentiometers must be identical, and the detection of a difference reflects the failure of one of the two. It is however obvious that this feature is not limiting and that a single potentiometer would perfectly fulfill the function to provide different levels of tension for different angles of rotation of the lock.

FIG. 3 shows an alternative embodiment of the switch according to the invention.

The housing 2a ', 2b' and the rotor 3 'are, in this case, slightly different since they adapt to the shape of the internal elements of this variant of the switch.

The potentiometers 5, 6 of the switch of Figure 1 have been replaced here by other components, performing a similar function.

Solidarity of the rotor are mounted a pair of sliders 12 and 13 independent, each consisting of a small metal plate having a series of double fingers for projecting from the plane of the wafer; these fingers are intended to slide on the tracks of a printed circuit (not visible in the figure) formed on a wafer 14 corresponding.

The fingers of the sliders 12 and 13 have the role of connecting together different points of the printed circuit, depending on the position of the rotor 3 'which they are integral, in a manner that will be explained later.

On the printed circuit board 14, and in connection with suitable points of the tracks of the circuit, are also arranged connecting lugs 15 and three resistors R ₁ , R ₂ , R ₃ ; the resistors remain connected in series via the printed circuit.

The connecting tabs 15 remain accessible from outside the portion 2b 'of the housing by an appropriate opening 9'.

The block diagram of an installation incorporating this switch is identical to that shown in Figure 2, except for a portion of the control circuit 20 which will vary accordingly.

The operation of the switch of FIG. 3 will now be described in more detail with reference to the diagram of FIG. 4.

The resistors R ₁ , R ₂ and R ₃ are connected in series and fed, by means of another resistor R ₀ , by a stabilized voltage, for example +5 V. In FIG. P ₁ and P ₂ two tracks of the printed circuit formed on the wafer 14 (Figure 3); on each of the tracks P ₁ and P ₂ slide two fingers of the cursor 12, which is shown schematically in Figure 4 by a line.

The fact of providing two contact fingers for each track, rather than just one, is not essential but offers the advantage of ensuring good contact, especially in resonance conditions, insofar as the difference in geometry of the two fingers avoids the risk of simultaneous resonance thereof.

As will be understood from examining FIG. 4, the circuit constitutes a voltage divider, in which the voltage V _x read by the control circuit depends on the position of the slider 12 and thus on the angle of rotation of the key in FIG. anti-theft: when the lock is in position A (the user has not yet turned the key), the electrical circuit is formed of three resistors R ₁ , R ₂ and R ₃ ; when the lock is in the B position (the user turned the key to the "on" position), the slider 12 bypasses the resistance R ₃ making contact with the track P ₁ , and the circuit remains formed resistors R ₁ and R ₂ ; and when the lock is in the C position (the user has turned the key to the "start" position), the slider 12 bypasses the resistors R ₂ and R ₃ making contact with the track P ₂ , and the circuit remains formed only of the resistor R ₁ .

The different resistance of the electrical circuit causes the voltage V _{x to} be different in each of the three positions of stop, run and start; for example, in a practical embodiment, the values of the voltage V _x for the three positions could be approximately 3.5 V (off), 2.4 V (on) and 1.3 V (start).

Depending on the voltage read, the circuit 20 activates the relays and electrical equipment described.

It is important to emphasize that each of the voltages is kept constant between two determined rotational angles of the antitheft, so that the reliability of the system is very high.

In a second embodiment of the switch, there is also provided an electrical circuit of the all-or-nothing type, which has not been shown insofar as its design is obvious to an expert in the field, intended to cause the "Wake up" of the control circuit 20 when the antitheft is placed in the "on" position. For this all-or-nothing circuit, slider 13 (FIG. 3) is used, which, as explained, turns together with slider 12 while remaining electrically independent of slider 12.

The embodiment with traditional potentiometers of Figure 1 offers the advantage of being extremely simple from the point of view of construction, and very economical; the embodiment of FIG. 3, on the other hand, is more reliable since it is capable of absorbing any peak power or variation of the power supply.

What is important in the two embodiments is that the switch comprises means for varying a voltage as a function of the angle of rotation of the antitheft device (these means are, in one case, the potentiometer and, in the other case, the combination of the sliders, the printed circuit and the resistances), and that the control circuit, following this voltage, governs the activation of the various electrical systems of the vehicle, so that only a weak current flows in the switch.

Claims (3)

1. Low current starter switch (1) for a vehicle steering column (1), comprising a rotor (3; 3') fixed in rotation to the cylinder of the anti-theft device, the axis of the cylinder (3; 3') being aligned with the axis of the anti-theft device, and an electric circuit, the said electric circuit being a low current circuit with variable resistance depending on the angular position of the rotor (3; 3'), the said electric circuit outputting an output voltage (Vx) that varies depending on the said resistance, characterised in that the said electric circuit comprises two potentiometers (5, 6), both associated with the rotation movement of the rotor (3) and that output independent output voltages.
2. Starter switch according to claim 1, characterised in that the resistance of the said potentiometer (5, 6) is variable in steps, presenting a series of different discrete values, each of which is kept constant over the entire range of an interval of angles.
3. Starter equipment for vehicles, including a starter switch (1), characterised in that the said starter switch (1) is of the type defined in either of claims 1 and 2, and in that it also comprises a control circuit (20) connected at one end to the output from the variable resistance electric circuit of the switch (1), and at the other end to at least two relays (21, 22), the said control circuit (20) activating each of the relays (21, 22) as a function of the output voltage of the variable resistance electric circuit.

Images