MXPA01002123A - Method for gradually driving a motor vehicle starter switch - Google Patents

Abstract

The invention concerns a method for powering a driving coil of a mobile core of a motor vehicle electrical starter switch, which consists in varying the efficient current in the coil while the core is moving towards its contacting position, and in adopting during said displacement:a first driving phase with sufficiently high efficient current to move the core;then a second driving phase with lower efficient current, whereby after a specific or predetermined time the efficient intensity is continuously increased.

Description

PROCEDURE OF PROGRESSIVE OPERATION OF A AUTOMOTIVE VEHICLE STARTING CONTACTOR The present invention relates to the procedures and control devices of automotive engine starters, and more precisely to the methods and actuators of the contactor core of these starters. As illustrated in Figure 1, a starting motor of an automotive vehicle commonly includes a contactor 2, as well as an electric motor M whose output shaft includes a pinion 1. The pinion 1 is intended to cooperate with the gear of the starter crown C of the heat engine. It slides on the motor shaft M between a position where it is disengaged relative to the mentioned starter ring and a position where it engages with it. The contact 2 extends parallel to the electric motor M above it and includes a winding 2a and a plunger core 2b. This ensures the control of the feeding of the electric motor M by moving a movable contact 3 between an opening position and a closing position, the mentioned contact 3 is pushed by the mentioned piston core 2b with axial movement in relation to the electric motor M when winding 2a is activated.

The contactor 2 also commands the displacement of the pinion 1. Its core of the piston 2b is for this reason, attached to the pinion 1 by mechanical means referenced in four within its assembly. These mechanical means include an orifice coupled to its upper end with the core of the piston 2b and at its lower end with a support to which the pinion 1 belongs. This support includes a freewheel interposed axially between a hub and the pinion 1. The The hub is internally provided with helical grooves in a complementary manner with external helical teeth placed locally by the output shaft of the electric motor M. The fork is pivotally assembled between its two ends on a casing that includes the mechanical means internally. 4 and which carries the motor M and the contactor 2. The support with its pinion 1 has a helical movement when it is moved by the fork to enter the socket with the starter crown. This is carried out by feeding the winding 2a after a drive of the ignition key, which makes it possible to set in motion the core of the plunger 2b thus attracted in the direction of a fixed core mounted on the end of a winding support 2a . This support has a U-shaped section for housing the winding 2a and thus includes a bottom constituting a bearing 2c. The core 2b is therefore intended to move between a rest position and a contact position, in which it is supported on the fixed core, this closing position of the magnetic circuit occurs after the closing of the moving contact 3 and therefore of the electric circuit.

The mechanical means also includes a return spring mounted around the core 2b to return the latter to its rest position, a cutting spring associated with the moving contact 3 to return it to its opening position and a spring 5, the said tooth against tooth spring, housed inside the core 2b and in socket with a first bar joined by an axis with the upper end of the clevis for coupling it with the core 2b. This spring 5 has a greater stiffness than the return spring. The cleat is thus interspersed at its upper end between the core 2b and the shaft. The first bar, mounted inside a hidden hole of the core 2b, is intended after a certain stroke, to be coupled with a second bar attached to the movable contact 3 and slidably mounted inside the fixed core. In the closed position, the contact 3 cooperates with a fixed contact, in the form of connecting terminals connected respectively to the positive terminal of the battery and to the electric motor M, thus allowing the supply of the electric motor. The connection terminals are connected to the closing hood of the insulating material contactor. All these elements are represented in figure 1 and have not been put as reference for simplicity.

The pinion 1 can then enter the socket with the crown C, that is, reach its gear position with the crown C, before the mobile contact closes. More commonly, the pinion 1 is placed axially in abutment contact with the teeth of the crown C before entering it. In this way, the mechanical means 4 mainly include a spring 5 which is mechanically interposed between the core of the plunger 2b and the pinion 1, and which allows the core of the plunger 2b to follow its course to guarantee, before its contact with the fixed core , positioning in the closed position of the movable contact, even when the pinion 1 is blocked in stop against the teeth of the heat engine crown, in a position where it does not engage with this crown. However, taking into account the speed of movement of the mobile core 2b and the elasticity of the mechanical linking means 4, mainly due to the presence of the spring 5, important displacements can occur between the closure of the contact 3 and the translation of the pinion 1. Particularly at low temperature, a rotation of the electric motor M and therefore of the pinion 1 can be observed before the latter has time to penetrate the crown. With the electric motor M being energized under full tension, the speed of the pinion 1 grows very rapidly, thereby including the gear of the pinion in the crown. Rapid destruction of the crown and pinion occurs.

In document FR-A-2 679 717, it is proposed to reduce this drawback of feeding the contactor by a current of variable pulses. Referring to Figure 2, in this type of arrangement, a coil B controls both a contactor K and the advance of a pinion not shown. Coil B is powered by means of a T-transistor in pulse mode, long pulse modulation type or "Pulse Width Modulation" (PWM) ("Width Impulse Modulation") in French, the transistor is piloted by a microcontroller 10. A cyclic ratio of the pulses is progressively increased to obtain an effective current in the coil that increases progressively. It is desired, in this way, that the mobile core begins to move with a minimum of magnetic attraction force and therefore a minimum acceleration, in order to avoid a shifting between the movement of the core and that of the pinion described above. This procedure has the same purpose of reducing the speed of impact of the pinion against the crown to reduce frontal wear of the latter. However, it does not allow to avoid a brutal displacement of the nucleus from its resting position towards its activation position. To further reduce this impact velocity, it is proposed in document US-A-4 418 289, in accordance with the preamble of claim 1, a method of feeding a driving coil of a moving core of the electric start contactor of the automotive vehicle, in which the effective current in the coil is varied during the course of the displacement of the nucleus towards its contact position, and in which, during the course of this displacement, it is adopted: a first phase of effective current drive raised to put the core in motion, in addition, - a second phase of driving the weakest effective current. This document also proposes a device for controlling the supply of a coil for driving a moving core of the starter contactor of an automotive vehicle, provided to vary the effective current in the coil during the movement of the core towards its contact position, in which it is foreseen for carrying out in the course of this displacement: - a first phase of effective current drive sufficient to set in motion the core, in addition, - a second phase of driving a weaker effective current . In practice, in the second phase, the electric motor is fed to rotate it at a reduced speed, thanks to a complementary disk, complementary contacts and a complementary resistance integrated to the contactor. This second phase ends with the closing of the mobile contact, which then cooperates with the fixed contact to feed the electric motor in full power.

This solution is not totally satisfactory since it complicates the realization of the contactor. On the other hand, it is not totally reliable because, for example, the support, and therefore the pinion can be blocked. The object of the present invention is to reduce these drawbacks in a simple and economical manner. According to the invention, a method of the type indicated above is characterized in that during the second phase, when the mobile core is not in contact position, a continuous increase of the intensity is carried out after a predetermined or predetermined time. effective. According to the invention, a device of the type indicated above is characterized in that during the second phase, the occurrence is foreseen, after a predetermined or predetermined time, of a continuous increase of the effective intensity. Thanks to the invention, the contactor has a simple shape and prevents a brutal movement of the core, from its rest position to its activation position. In effect, the effective intensity in the first interval of the second phase is lower than that in which the solution of document FR-A-2 679 717 is exited since the core is detached. In this way, noise is reduced and the solution is safe. In fact, after a predetermined or predetermined time, the progressive increase of the effective intensity allows, on the one hand, to progressively compress the spring, tooth against tooth 5, and on the other hand, the closure of the contactor to feed the electric motor in a accidental case in which the contactor could not be closed previously. In this way, in the accidental case in which the abnormally high friction forces occur within the contactor, in the mechanical means or at the level of the electric motor shaft, the closing of the contactor is guaranteed beyond a predetermined or determined time. These cases can occur after particular climatic conditions, in seizures, mainly when the vehicle has been without movement for a long time. The dust, the dirt, can settle at the level of the fork and the electric motor shaft and therefore obstructs the movement of the pinion. Thanks to the invention, it is possible, in spite of this, to move the support and its pinion. In addition, the contact of the pinion stopper with the starter crown is carried out, either before the increase in intensity, or after the increase in intensity and before the closing of the mobile contact, in such a way that the electric motor starts from zero speed in this contact position of the stop, which facilitates the penetration of the pinion in the crown, thus reducing wear. The solution according to the invention is therefore reliable and allows to increase the life of the starter motor thanks mainly to a reduction in wear.

On the other hand, the consumption of energy and noise is reduced. The solution is economical since the contactor can only present a single winding.

Thanks to the invention, measurements can be made during the first phase. This first phase can be divided into two intervals, namely a first high effective current interval followed by a second current interval weaker than that of the second phase. Preferably, this second interval is carried out with zero current for a better accuracy of the measurement. In the same way, you can measure the voltage of the battery during the first phase. During this first phase, the nucleus can detach with a weaker stroke, the intensity being during the first interval of this first phase close to the intensity needed to take off the core and taking place in a shorter time. If later problems arise, if the core does not detach, there is no closure of the contactor for example, thanks to the continuous increase of the effective intensity according to the invention, these problems will be solved. The limit detachment of the core makes it possible to further reduce shocks, brutal displacements, and reduce energy consumption. Thanks to the invention, the winding has a double function since, after a third interval of the second phase, by means of which the intensity of the effective current is increased, it allows, after turning the electric motor in rotation, to keep the contact closed mobile during a third phase.

It will be appreciated that the electric motor does not rotate until after the pinion comes into contact with the crown, so that the pinion can penetrate the crown more easily and the wear is reduced. Thanks to the invention in the first phase, it is possible to be at the limit of the detachment of the core in such a way that the movement thereof is even less brutal. The time is determined based on the abnormal values that occur in case the mobile contact does not close. The time is determined depending, for example, on the battery voltage or the winding temperature. The time can easily be predetermined so that the continuous increase in intensity does not occur more than in case of necessity, that is, for this time to be as short as possible and include the majority of normal cases of operation. Other features, purposes and advantages of the invention will appear on reading the following detailed description, will make reference to the appended figures, in which: - Figure 1 represents a starter of an automotive vehicle according to the state of the technique; - figure 2 represents a supply assembly of a starting contactor according to the state of the art; - Figure 3 is a diagram showing the evolution of a cyclic link of supply voltage of a coil of the contactor, according to the invention; - Figure 4 is a partial view analogous to figure 3 for another embodiment. As illustrated in FIG. 1, the core of the piston 2b is arranged inside the bearing 2C according to a sliding ratio modulated by the presence of a lubricant which guarantees a sealing and braking function. The core 2b is therefore a mobile core. The core presents, in its resting position, a force of adhesion in the bearing Fa which opposes its setting in motion. When the nucleus is set in motion, this force Fa disappears for the benefit of a friction force Ff, which is clearly lower than Fa (in an order of 20 to 40% lower). The presence of the lubricant does not eliminate these forces. On the other hand, due to a lubricating effect of the lubricant, this further accentuates the fact that the adhesive force Fa exceeds the frictional force Ff. The mobile core 2b remains at rest while the coil 2a does not exert a driving force Fm that is greater than Fa. During the start-up of the core 2b, the effective intensity in the coil 2a is progressively increased. The forces of retention of the nucleus diminish drastically (of Fa to Ff) with the setting in movement of the nucleus, whereas the force of attraction Fm achieved already has a high value in the exit of the nucleus. This difference between Fm and Ff therefore induces a sudden acceleration of the mobile core in the unlocking movement of the core in such a way that the progressive feeding does not in this way produce the desired effects. Here, a coil feed device 2a is used, the assembly of which is similar to that shown in figure 1, and in which a supply of the coil 2a is adopted here in accordance with a loophole voltage of the PWM type. However, the cyclic link is varied in the course of the displacement of the core according to the evolution represented in Figure 3 and this is after a predetermined or determined time. In this diagram, the successive instants in the course of the kernel displacement are indicated in abscissa, their initial resting position (instant To) in a final position ("kernel call period") where it is in stop against the fixed core and where the contact is guaranteed, the mobile contact 3 being closed. The call period of the nucleus is divided into two main phases, where the second is divided into three subphases. Next, these two main phases will be described. During the first phase that goes from instant t0 to an instant t-i, a cyclic link R1 is adopted, close or equivalent to 100% (the cyclic link is the relation between the duration of the conduction of the transistor T-i and the total duration of a cycle). During this phase, a high effective intensity passes through the coil 2a and the core 2b is subjected to a force of attraction Fm sufficient to detach from its rest position and to move. This phase is brief, in this case, in an order of 2 to 10 ms, so as not to produce a high attractive force on the nucleus but for the purpose of detaching it. The second phase is carried out between the instant t-i and an instant t3. In a first interval of this second phase, the transistor Ti controls the contactor according to a cyclic link that has a value R2 substantially equal to 50%, in such a way that the effective current in the coil 2a is clearly reduced by reference to the obtained during the first phase, sufficient only to overcome the residual frictional forces Ff after the detachment of the core 2b. During this interval, which lasts approximately 30 to 60 ms, the core 2b then continues its movement until the contactor closes, without excessive brutality and speed. During this first interval of the second phase, in the general case axially a stop contact between the pinion 1 and the starter crown is obtained between the times t1 and t2. More precisely, the microcontroller 10 is connected by one of its inputs with a temperature sensor placed inside the contactor 2a in the vicinity of the winding 2b and is similarly connected by a second input in the power terminals of the motor Boot. The microcontroller 10 shows on these two inputs signals representative of the temperature T of the contactor, therefore of the coil 2a and of the supply voltage U at the starter motor input. The starting voltage of the starter motor is variable depending on the state of charge of the vehicle's battery and the temperature. In effect, the temperature of the coil 2a directly conditions its resistance. Or, when the average current is obtained by a given cyclic relationship, it depends directly on the voltage available at the terminals of the starter motor - therefore, at the terminals of the battery - and the resistance of the coil 2a. In this way, the microcontroller 10 includes a memory in which a numerical table is registered which corresponds, by a desired effective intensity, the cyclic link R2 to be adopted as a function of the starting voltage of the starter motor and the temperature of the coil. In practice, R2 is in an order of 0.4 to 0.6 at a temperature of 20 °. The effective intensity is substantially constant in this first interval. In this way, the microcontroller 10 automatically adopts a cyclic link R2 as a function of the supply voltage at the starter motor terminals and the winding resistance (this depends on the temperature). The measurements of the voltage U and the temperature T are carried out in a beneficial manner before starting the first phase described above, at the moment of starting the starter motor. In a second interval of the second phase, which runs between the instant t.2 and the instant t.3, and according to the invention after a predetermined time or a certain variant, the microcontroller 10 carries out a continuous increase and progressive of the cyclic link, going through the link R2 to rediscover the link R1 or as a variation, a link greater than R1. This interval has a duration of approximately 20 to 50 ms and allows to guarantee, by means of the progressive increase of the effective intensity, that of the contactor, in an accidental case in which the contact could not be closed between t1 and t2. An accidental case of this type can occur mainly if abnormally high friction forces are present in the contactor, in the mechanical means 4 and at the level of the motor shaft M. These abnormal forces are due, for example, to climatic phenomena, expansion, seizure, the presence of impurities, dirt and all types of stains, mainly at the grooves. of the electric motor shaft and the fork joints. During this second interval, the spring is compressed, tooth against tooth 5 to allow the core of the piston 2b to actuate the moving contact 3 to feed the electric motor and to make a rotation of its shaft in order to guarantee a penetration of the pinion into the crown, and therefore, a gear of the pinion with the crown. Of course, in the case where the movable contact closes between the times t1 and t2, and the pinion meshes with the crown 3, there is no way to perform the continuous increase of the intensity since the gearing is done before a predetermined time according to the applications. In 90% of cases, the mobile contact closes before this predetermined time as short as possible to encompass normal functions. As a variation, this time is determined, for example, as a function of the battery voltage or the temperature of the winding 2a, these magnitudes are influenced by the lack of closure of the moving contact which produces abnormal values.

In all cases, in a complementary interval that is presented in Figure 3 between the instant t3 and a time t4, the cyclic link is maintained in R1 or a value greater than R1 for about 5 to 30 ms. This high cyclic bonding phase begins with the closing of the movable contact 3 and keeps the core 2b in its contact position (mobile contact 3) with a high attractive force preventing rebounding of the movable core 2b against a stop usually formed by another core , fixed to this one. This third interval t3, t4 lasts a sufficient time to be able to absorb the points of the current caused at the start of the thermal engine by the electric motor M, which according to a characteristic of the invention is not piloted. According to one characteristic of the present, it is not until after the crown stop with the pinion that the increase in the cyclic linkage is carried out. After the third interval a cyclic link R3 is adopted in a third phase at the terminals of the winding resistance 2a to maintain the movable contact in the closed position. The effective current is weaker in that third phase than in the other two phases. As understood and as a result of the description, a single winding 2a is necessary and the microcontroller can be mounted on a support, such as a plane, in the starter motor, more precisely mounted in the vicinity of the winding 2a within the space comprised between the moving contact 3 and the hood (not referenced in Figure 1) carrying the fixed contacts. Thanks to the invention and to the modulation of the pulse elongation during the first phase, more precisely at the beginning of this, a measurement of the current and therefore of the battery voltage can be made knowing that, in the manner before mentioned, the average current obtained by a given cyclic link depends directly on the voltage available at the terminals of the battery. With the help of the numerical table registered in the microcalculator 10, the desired cyclic link is adopted after the output of the first interval of the first phase. Also in figure 4 the first phase is divided into two intervals tO-t 'and' -t'1. In the first cyclic linking interval R'1 is 100%. In the second interval the cyclic bond is lower than the cyclic link R2. In a beneficial manner in FIG. 4, the cyclic link within the second interval of the first phase is zero for a greater accuracy of the measurement. In practice, the effective current during the first interval of the first phase is less high than that of figure 3 being in the vicinity thereof. This effective current is therefore higher than that of the second phase in the cyclic bond R2. The duration t 'of the first interval is less than the duration tel.

The duration t'-t'1 of the second interval is greater than the duration t 'of the first interval. This duration is here more than twice that of the first interval and allows a correct measurement to be made before the start of the second phase. For example, for a time of t1 of 4ms, the time t 'is 3ms and the time of the second interval t'1-t' of 7ms. The current at the end of phase 1 is approximately less than 3A to that of figure 3. In figure 4, the displacement of the core in phase 1 is less than half that of figure 1. With the relation R ', we are in the vicinity of the limit of the release of the nucleus. Of course, in figure 4 for simplicity, the other intervals of the second and third phases have not been represented. The device and method proposed here make it possible in this way to improve the progressiveness of the movement of the mobile core 2b and the pinion 1. This results in an increase in the life of the pinion 1 and of the drive crown, as well as an noticeable reduction of the noise created by the impact of the pinion against the crown. Even when the core does not come off during the first two phases, the detachment of this one can be achieved. The electric motor is not piloted in the current. The solution is simple, reliable and economical. Of course, in Figure 3, the intensity of the effective current in the first phase can be decreased. Everything depends on the displacement of the core of the piston that you want to have. In relation to the prior art, we can get as close as possible to the limit of detachment of the nucleus and better control the displacement of the latter playing mainly with the duration of the first phase. In the prior art, it was necessary to foresee a more important safety coefficient in order to be sure of the nucleus detachment. Thanks to the invention, the detachment of the core is less dramatic and is better controlled, and the first interval of the second phase is produced with a substantially constant effective intensity. As has been understood by having the microcontroller 10 on a plane in the aforementioned manner in the vicinity of the winding 2a, the temperature thereof can be measured by placing on the plane a resistance linked to the microcontroller and variable as a function of temperature, for example , in a positive or negative temperature coefficient.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. - Procedure for feeding a coil (B) for driving a mobile core (2b) of the electric starting contactor (2) of an automotive vehicle equipped with an electric motor (M), in which the effective current in the coil (B) in the course of the displacement of the core (2b) towards its contact position, to close a moving contact (3) and feed the electric motor (M), in which it is adopted in the course of this displacement: a first drive phase (to, tt) with a sufficiently high effective current to set the core (2b) moving, in addition, a second phase (ti, t2, t3) of drive with a weaker effective current, characterized in that it is carried out, during the second phase (ti, t2, t3) after a predetermined or determined time, a continuous increase of the effective intensity.

2. Method according to claim 1, characterized in that the effective current during the second phase (t1 f t2, t3) is in an order of 0.4 to 0.6 times this applied during the first phase (t0, ti).

3. Method according to claim 1 or 2, characterized in that the first phase includes a first effective current range sufficiently high to set the core (2b) in motion and a second effective current range weaker than that of the second. phase, to say null.

4. - Method according to one of the preceding claims, characterized in that a phase (t3, t4) of high intensity is carried out after the closing of the mobile contact (3).

5. Device for controlling the supply of a coil (B) for driving a moving core (2b) of the ignition contactor (2) of an automotive vehicle, provided to vary the effective current in the coil (B) in the course of the displacement of the core (2b) towards its contact position, to close a mobile contact (3) of the contactor (3) and feed the electric motor, in which it is foreseen for the realization in the course of this displacement: - a first phase (t0, ti) of drive with sufficient effective current to set the core moving, in addition; a second phase (ti, t2, t3) of drive with a weaker effective current, characterized in that during this second phase the realization is envisaged, after a predetermined or determined time, of a continuous increase of the effective intensity.

6. Device according to claim 5, characterized in that it includes the means for measuring a starter supply voltage and means for adapting the effective current level during the second phase (ti, t2, t3) as a function of this voltage.

7. Device according to claim 5 or claim 6, characterized in that it includes the means for measuring a resistance of the coil (B) and for adapting, as a function of this resistance, the effective current during the second phase (ti, t2, t3).

8. Device according to any of claims 5 to 7, characterized in that it includes the means for measuring the temperature and the means for adapting the effective current during the second phase (ti, t2, t3) as a function of this temperature. Device according to one of claims 5 to 8, characterized in that it is provided for supplying to the coil (B) a loophole voltage whose cyclic link (Ri, R2) is different in the first (t0, ti) and the second phase (t ?, t2l t3). 10. Device according to claim 9, in combination with any of claims 6 and 8, characterized in that it includes the means (10) to reduce the cyclic link (R2) of the coil feed (B) as a function of or of the results provided by the measurement means or means.