EP0960276A1

EP0960276A1 - Circuit for a latching relay

Info

Publication number: EP0960276A1
Application number: EP97949879A
Authority: EP
Inventors: Stefan Renner; Claus Kramer; Karl-Otto Schmidt; Uwe Daurer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1997-01-28
Filing date: 1997-11-06
Publication date: 1999-12-01
Anticipated expiration: 2017-11-06
Also published as: BR9714535B1; DE19702932A1; JP2001508850A; WO1998032966A1; BR9714535A; EP0960276B1; US6323562B1; DE59706819D1; JP4118344B2

Abstract

The invention relates to a circuit for a latching relay engaging two toothed wheels in a starting device of an internal combustion engine, characterized by a control and regulating device (2) reducing the relay current after a first time interval (4) to a given current value during a second time interval (41) before both toothed wheels are engaged.

Description

Circuit arrangement- for an engagement relay

State of the art

The invention relates to a circuit arrangement for an engagement relay of a starter device of an internal combustion engine, which engages two gears.

From the document DE 195 035 36 a circuit arrangement for an engagement relay is known which has a control and / or regulating circuit influencing the operating current of an auxiliary relay. The auxiliary relay in the prior art is used to decouple the current flowing from an ignition start or travel switch during the starting process of an internal combustion engine via the relay coil of the engagement relay. This happens because the auxiliary relay switches the current required for the engagement relay, which can be approximately 80 to 100 A. The auxiliary relay requires a small Ren operating current, which can be switched with the ignition start or travel switch with this version.

The controlled or regulated current makes it possible to reduce the size of the auxiliary relay.

In the embodiment known in the prior art, it is disadvantageous that only the operating current of the auxiliary relay can be controlled or regulated. Regulation of the current of the engagement relay is not provided. Accordingly, the engagement relay always works with a constant current during the starting process of an internal combustion engine, which current is dimensioned such that the engagement relay develops a sufficient magnetic force in any case. A major disadvantage of the known design results from a hyperbolic force-displacement characteristic of a relay, namely when the air gap becomes smaller, an unnecessarily high acceleration of the engagement relay armature is achieved. Since the engagement relay armature moves the drive pinion of the starter device axially by means of a lever mechanism, there is consequently also a high acceleration of the drive pinion. If the drive pinion is set relative to the gear to be driven during a starting process in such a way that two teeth of the respective gear wheels are directly opposite one another, the two gear wheels cannot be brought into engagement with one another. If the drive pinion, which is very strongly accelerated via the engagement relay and the lever mechanism, hits the gear to be driven, the two gears must be very high Forces are compensated. These high forces can lead to complete destruction of the gear teeth.

Furthermore, devices are known in the prior art which rotate one gearwheel relative to the other when two gearwheel teeth meet. These devices are known as single-track transmissions. The disadvantage here is that the drive pinion, which is moved relative to a gearwheel, is very strongly accelerated with an engagement relay via a lever mechanism, as already mentioned. As a result, gear wear is increased by the combination of the high forces which are transmitted to the drive pinion via the engagement relay and the rotary movement which is brought about by the single-track gear, since the two gear elements are lined up by the force and the rotary movement. This leads to the well-known "ratcheting".

Another embodiment in the prior art is known in which the starter motor of the starter takes over the task of the single-track transmission. In this embodiment, if the teeth of the drive pinion meet those of the gear to be driven, the motor of the starter device is energized with its nominal current, so that the drive pinion is quickly moved and engaged relative to the gear to be driven. The force acting on the drive pinion through the engagement relay in combination with the high motor speed leads to high wear or even to their destruction, caused by the "ratcheting" of the gear elements. In the case of vehicles which are provided for a start-stop operation in the course of the reduction in gasoline consumption and consequently have an increased number of starts, the service life of the starter would be short.

Advantages of the invention

The invention relates to a circuit arrangement for a two-wheel engaging engagement relay of a starting device of an internal combustion engine, which comprises a control device that lowers a relay current after a first time period before the engagement of the two gear wheels to a specific current value during a second time period.

The circuit arrangement according to the invention has the advantage that the control device provided lowers the relay current to a predetermined current value after a first time period before the engagement of the two gears during a second time period, as a result of which lower magnetic forces occur which act on the relay armature. Through the. Hyperbolic force-displacement characteristic of the relay prevents an unnecessarily high acceleration of the drive pinion when the air gap between the relay armature and relay coil decreases and the relay current decreases.

This results in a reduction in wear for the starter device due to lower forces which act when the gearwheel elements meet, so that a lifespan extension is achieved for the starter pinion and the gear rim. As a result, the possible starting numbers of this starter device can be increased to 5 to 10 times the value.

Furthermore, the circuit arrangement according to the invention achieves a reduction in noise when the drive pinion is engaged in the gearwheel to be driven. The noise reduction is achieved in that when the teeth meet, the starting motor of the starting device rotates at a greatly reduced speed, so that the so-called "ratcheting" of the two gear elements is avoided.

A further advantage results from the fact that the drive pinion is accelerated less strongly during the second period, and when the drive pinion strikes a suitable pinion travel limiting device, for example a stop ring attached to the rotor shaft, no high forces arise which "bounce back" the drive pinion. . This means that the engagement process is carried out safely when the two gear wheels are in a "tooth-on-gap" position; so that the pinion is not thrown back in its engaging movement by large forces that occur when the pinion strikes the stop ring and is possibly disengaged from the gear to be driven.

In an advantageous embodiment of the invention it is provided that the control and regulating device by means of a single control end stage controls the current of the engagement relay as well as that of the starter motor during the engagement process. The relay winding is designed so that the number of turns is reduced while increasing the conductor cross-section. From this, the same force-displacement characteristic of the relay can be derived as that of a standard relay, however, the relay current must be increased to a current in the order of 100 A to 150 A, the relay current being controlled and regulated by the circuit arrangement according to the invention .

In this embodiment, the relay is connected in series with the field winding or armature winding, for example in the case of a series motor.

If the relay current reaches a level necessary for starting the rotor during a starting process, the relay current "flows" through the series connection of the relay winding and the excitation winding or armature winding mentioned above, and the rotor starts to move at a lower speed. Characterized in that the drive pinion is mounted on the rotor shaft in a rotationally fixed manner, the drive pinion rotates relative to the gear to be driven during the engagement process and can thereby mesh into a gap between two teeth of the gear to be driven.

Another advantageous embodiment of the invention results in an embodiment which is distinguished in that both the relay current and the starter motor current are decoupled can be regulated or controlled from each other, both a temporal decoupling of the axial and rotational movement of the pinion and a force decoupling can take place. It is thereby advantageously possible to apply a higher axial force for engaging or engaging the drive pinion while simultaneously reducing the drive torque of the rotor.

Further advantageous embodiments of the invention result from the subclaims.

drawing

The invention is explained in more detail using exemplary embodiments with reference to the drawings. Show:

FIG. 1 shows a starting device for an internal combustion engine connected to a first exemplary embodiment of the circuit arrangement,

FIG. 2 shows a graphical representation of the axial path of the drive pinion, the motor current and the pulse-width-modulated relay voltage over time, the respective graph resulting from the fact that the starting device is operated with the circuit arrangement according to FIG. 1, FIG. 3 shows a block diagram of a starter device of an internal combustion engine in connection with a second exemplary embodiment of the circuit arrangement,

FIG. 4 shows a graphical representation of the axial path of the drive pinion, the motor current and the relay current over time, the respective graph resulting from the fact that the starting device is operated with the circuit arrangement according to FIG. 3,

FIG. 5 shows a block diagram of a starter device of an internal combustion engine in connection with a third exemplary embodiment of the circuit arrangement,

6 shows a graphical representation of the axial path of the drive pinion, the motor current and the relay current over time, the respective graph resulting from the fact that the starter device is operated with the circuit arrangement according to FIG. 5,

FIG. 7 shows a block diagram of a starting device of an internal combustion engine in connection with a further exemplary embodiment of the circuit arrangement, and Figure 8 is a graphical representation of the axial path of the drive pinion, the motor current and the relay current over time, the respective graph resulting from the fact that the starter is operated with the circuit arrangement according to Figure 7.

embodiments

For the first and second exemplary embodiment of the starting device of an internal combustion engine, a thrust screw drive starter without a countershaft is provided as an example. This means that the drive pinion is engaged in the gear ring to be driven in the case of a thrust screw drive starter in the axial direction, the drive pinion being displaceably guided on the rotor axis of the starter motor and the axial displacement simultaneously causing the rotational movement of the pinion on the rotor shaft. For example, in the case of a mechanical single-track gearbox, this is done by means of a steep thread introduced on the surface of the rotor axis, into which a driver engages, which causes the rotational movement of the drive pinion on the rotor axis due to the axial movement of the pinion, since the rotational movement of the pinion mounted on the rotor shaft tests directly from Engine stops. In this exemplary embodiment of the push-screw drive starter without countershaft, the drive pinion is slidably mounted on the rotor axis, but is directly on the rotor shaft during the starting process driven, whereby the pinion rotates at the same speed as the rotor of the starter motor.

For the third and fourth exemplary embodiments, the aforementioned push-screw drive starter without a countershaft is also assumed by way of example, but a mechanical single-track transmission can be dispensed with here. This means that the drive pinion does not have to be rotated on the rotor axis during an engagement process.

Furthermore, a series motor is provided for the exemplary embodiments mentioned at the beginning, that is to say an armature winding and an excitation winding of the starter motor are connected in series. Of course, embodiments with a permanently excited motor are also conceivable. Design variants of the starter device are also conceivable which translate a countershaft arranged between the rotor axis and the drive pinion, which in a suitable manner translates the engine speed to another speed at which the pinion is driven. Of course, it is also conceivable that other embodiments are also possible for the starting device. It is therefore clear that the circuit arrangement according to the invention can be used for all common types of starters.

FIG. 1 shows a starting device 1, which comprises a control device 2, which is a component of a complex starting process control device (not shown here), and a starter 3 of an internal combustion engine, of which only a ring gear 6 to be driven is shown here. Furthermore, an ignition start or driving switch ter - hereinafter referred to as the start switch 4 - and a battery 5 of a motor vehicle, not shown here.

The starter 3 comprises an engagement relay 7, a starting motor 51, a single-track gear 52 and a contact bridge 10.

The engagement relay 7 is composed of a relay armature 8, a pull-in winding 9 and a holding winding 53. The contact bridge 10 can be actuated via the engagement relay. The engagement relay 7 is held by a web 11 within a housing 12 of the starter 3. A return spring 14 is provided on a relay armature 8 between the web 11 and a ring 13. At the end of the relay armature 8, an engagement lever 15 is articulated. The engagement lever 15 is pivotally mounted in a bearing 16 which is fastened to the housing 12. The engagement lever 15 is also connected to a guide ring 17. The guide ring 17 is displaceably mounted on an extension 18 which is part of a roller freewheel 19. On the peripheral surfaces of the extension 18, an engagement spring 20 is attached. The drive pinion 21 is assigned to the roller freewheel 19. The roller freewheel 19 is slidably mounted on a rotor shaft 22, which is part of the starting motor 51, in the longitudinal direction of the rotor shaft. A stop ring 23 is mounted on the rotor shaft 22 in such a way that the displaceability of the roller freewheel 19 in the longitudinal direction of the rotor shaft is limited, but engagement of the drive pinion 21 with the ring gear 6 is possible. There is a on the rotor shaft surface High-helix thread 24, into which a driver of the roller freewheel 19 (not shown here) engages. An armature 25 is also attached to the rotor shaft 22. A commutator 26 is associated with the armature 25, on which carbon brushes 27 loaded by spring pressure lie. The commutator 26 is in a known manner in conductive connection with an armature winding 27. At a distance, referred to as an air gap 28, the armature 25 is assigned an excitation winding 29, which is attached to a pole piece 30.

In the housing 12 of the starter 3, bearings 31 are also introduced, in which the rotor shaft 22 is rotatably but essentially axially immovable.

The control device 2 assigned to the starting device 1 is connected in electrical connection with the starter 3 in such a way that it is in conductive connection on the one hand with the start switch 4 and on the other hand with a contact 32 of the pull-in winding 9 and the holding winding 53.

The graphic representation in FIG. 2 shows in the upper diagram a qualitative course of the relay voltage U _rl over time t, in the middle diagram a qualitative course of the motor current I ^ over time and in the lower diagram the path s that the drive pinion 21 in has covered the axial direction on the rotor shaft 22 as a function of time.

Figure 3 shows the second embodiment of the circuit arrangement according to the invention, wherein -how already mentioned at the beginning - the starter 3 is in the same embodiment as in the first exemplary embodiment, therefore its components are not described again, so that only modifications of the circuit arrangement in relation to the exemplary embodiment 1 are discussed here.

Figure 3 shows a starter la, the control device 2a, the starter 3, the

Start switch 4, a battery connector 34 and a current sensor 33 comprises.

Like the control device 2 in FIG. 1, the control device 2a is connected to the starter device la, in that it is in an electrically conductive connection with the start switch 4 on the one hand and with the relay contact 32 on the other hand. Furthermore, a current sensor 33 is attached, which is arranged between the electrical connection of the control device 2a and the relay contact 32. The current sensor 33 is connected via an electrical connection 35 to a feedback input 36 of the control device 2a. The control device 2a is designed here as a two-point controller 37.

The graphs in Figure 4 show in the upper diagram a qualitative course of the relay current I 2 i ⁿ a function of time t, in the middle diagram a time-dependent, qualitative course of the motor current I _m2 and in the lower diagram illustrates a qualitative variation of the axial pinion path s a function of time t.

FIG. 5 shows a starter device 1b with a third exemplary embodiment of the circuit arrangement in connection with a starter 3b, the starter 3b here having a modified engagement relay 7b. 5 also shows a starter switch 4, a control device 2b and a battery connection 34.

The modification of the engagement relay 7b with respect to the engagement relay 7 in Figure 1 is that the number of turns of the pull-in winding 9b is reduced, but the conductor cross-section of the pull-in winding 9b is increased. This results in an increased current requirement of the engagement relay 7b in order to apply the same force as that of an engagement relay 7 from FIG. The required current strength is, for example, in the range between 100 A to 150 A. For the control device 2b, the same functioning results as that of the control device 2 from FIG. 1, but with an actuation output stage, not shown here, which is part of the control device 2b, for an increased level Current carrying capacity is formed.

In the embodiment of the starter 3b shown here, a modification is that the single-track spring 20, as shown in FIG. 1, can be omitted. This modification results from the function of the starting device 1b, which will be dealt with at a later point in time.

The graphic representations in FIG. 6 show in the upper diagram a qualitative course of a relay current I _r3 as a function of time t, in the middle diagram a qualitative, time-dependent course of a motor current I _{m3 of} the modified starter 3b from FIG. 5 and the lower diagram a qualitative course of the path s which the drive pinion 21 of the starter 3b travels axially and as a function of time.

FIG. 7 shows the fourth exemplary embodiment of the circuit arrangement according to the invention of a starter device lc, which comprises a battery connection 34, a start switch 4, a control device 2c and a starter 3c.

The starter 3c has a modification in comparison to the starter 3 from FIG. 1, which is distinguished by the fact that the engagement spring 20 from FIG. 1 can advantageously be dispensed with. Furthermore, the starter 3c has an additional connection 38 which is electrically connected to a second output 39 of the control device 2c. The second output 39 is a control output for the starter motor 51.

Otherwise, reference is made to the components of starter 3 from FIG. 1.

The graphic representations in FIG. 8 show in the upper diagram a qualitative course of a relay _current I _r4 over time t, the middle diagram shows a qualitative course of a motor current I _m4 over time t and the lower diagram shows a time-dependent, qualitative course of the axial pinion travel s.

The respective mode of operation is explained below using the exemplary embodiments. If the start switch 4 shown in FIG. 1 is actuated as a result of a desired starting process of the internal combustion engine, the battery voltage is applied to the control device 2 via the closed start switch 4. The control device 2 provides a control signal in pulse width modulated form with a fixed clock frequency. The pulse width ratio D, which indicates the duty cycle of a switching transistor in relation to the clock period within a clock period, is set to "1" in a first time period 40 — shown in FIG. 2 in the upper diagram. This means that the duty cycle corresponds to the period of the clock frequency. In this first time period 40, in which the pulse width ratio D = 1, a switching transistor, which is part of the control device 2, switches the full battery voltage through to the engagement relay 7, so that the relay current increases in accordance with the ohmic resistances and inductances which have flowed through. The engagement relay 7 develops in this time period 40 the full relay force which is necessary for “tearing away”, for example in the case of low outside air temperature, of the relay armature 8 and also for overcoming the static friction and the first spring forces.

In this time period 40, the relay armature 8 is moved to the right in the image, that is to say it is drawn into the pull-in winding 9 of the engagement relay 7. This process causes the engagement lever 15 to pivot about its bearing 16 in a clockwise direction, whereby the engagement lever 15 the roller freewheel 19 together with the drive pinion 21 by means of the Guide ring 17 in the picture is moved to the left, ie in the direction of the ring gear 6. This results in a distance s traveled for the drive pinion 21, as is shown as a function of time in FIG. 2 in the lower diagram.

There now follows a second time period 41 during which the pulse width ratio D is reduced to a value less than 1, so that the relay current drops to a value which is less than the relay current in the first time period 40.

In this time period 41, the relay armature 8 is drawn into the pull-in winding 9 of the engagement relay 7 with reduced force, as a result of which the drive pinion 21 approaches the ring gear 6 at a reduced speed. The length of the second time segment 41 must be dimensioned such that the drive pinion 21 always reaches the ring gear 6. The relay armature 8 of the engagement relay 7 is drawn so deep into the pull-in winding 9 that it closes the contact bridge 10 via a linkage, which is shown in broken lines in FIG. 1 and is in mechanical connection with the contact bridge 10, so that a conductive connection between the battery 5 and the excitation winding 29 is formed. At the same time, the holding winding 53 is switched on via the closed contact bridge 10 and the pull-in winding 9 is short-circuited.

The rotational movement of the armature 25 is caused by the motor current I _ml flowing through the contact bridge 10, as a result of which the rotational movement of the armature 25 is transmitted to the ring gear 6 via the rotor shaft 22 and the drive pinion 21. Simultaneously tig at the beginning of the rotary movement of the armature 25, the pulse width ratio D within the control device 2 is reset to the value D = 1 in a third time period 42. As a result, the engagement relay 7 can again develop its full force so that the drive pinion 21 remains securely in engagement with the ring gear 6.

If, during the engagement process, there is a drive pinion position which does not allow the drive pinion 21 to be brought into engagement with the ring gear 6, for example if two teeth of the gearwheel elements are directly opposite one another, the movement of the engagement lever 15 to the left causes the Overcoming the spring force of the engagement spring 20 and setting the drive pinion into a rotary movement via the engagement gear 52. This is done by moving the guide ring 17 to the left in cooperation with the driver (not shown here), which engages in the steep thread 24, as a result of which the drive pinion 21 rotates in the manner described at the beginning and thereby engages the drive pinion 21 with the ring gear 6 is made possible.

If the starting process of the internal combustion engine is initially ended, that is, no torque is transmitted from the starter 3 to the gear 6, if the torque is transmitted from the ring gear 6 to the drive pinion 21, the drive pinion 21 is transferred via the roller freewheel in a manner known in the prior art 19 spurted out again. Torque is transmitted from the ring gear 6 to the drive pinion 21 when the speed of the internal combustion engine seem greater than that of the crank motor 51. After the starting process, all mechanical elements that have been pivoted or moved during the starting process return to their starting position and the motor and relay current are switched off. The relay current is switched off via the start switch 4, so that the engagement relay 7 "drops out" and the contact bridge 10 opens.

The exemplary embodiment of the circuit arrangement shown in FIG. 3 has the same functional sequence as the starter 3 shown in relation to the mechanical components of the starter 3. In this respect, only the functioning of the control device 2a is explained.

For the desired starting process, the start switch 4 is closed, so that a conductive connection between the battery, represented by the battery connection 34, and the control device 2a is established. In contrast to the control device 2 in FIG. 1, the relay current I _{j is} not changed via the pulse-width-modulated relay voltage, but rather by means of a two-point regulator 37 known here in the prior art.

The two-point controller 37 allows the relay current I _r 2 to be set to two values. Advantageously, the two-point controller 37 enables a current sensor 33, which is connected via an electrical connecting line 35 to the feedback input of the two-point controller 37, to detect the current value specified by the control device 2a by means of the current sensor 33 and the actual value to the target value to adapt the current I _r2 . The relay current I _{r2 is} shown in the upper diagram in FIG. A current value is set for the starting process in the first time segment 40, which results inevitably after the battery voltage applied to the engagement relay 7 as a function of the ohmic resistances and inductances. The engagement relay 7 develops the force required to "tear away" the relay armature 8.

During the second time period that follows, the two-point controller 37 reduces the relay current I _r2 to a lower value. If the drive pinion 21 is fully engaged in the ring gear 6, the third time period 42 begins during which the two-point regulator 37 raises the relay current I ^ to the increased value again. At the same time, the motor current I _m 2 is switched on via the contact bridge 10 at the beginning of the third time period, so that the actual starting process of the internal combustion engine takes place.

In the case of a tooth-on-tooth position, as already described in the first exemplary embodiment, a mechanical drive pinion rotation takes place analogously to the first exemplary embodiment.

When the starting process is complete, the drive pinion 21 is extracted from the ring gear 6 in a known manner, all mechanical components of the starter 3 being returned to their starting position. As described in the first embodiment, the motor and relay current are switched off. The function of the third exemplary embodiment is described below with reference to FIG. 5.

A modified starter 3b is used for the third exemplary embodiment of the circuit arrangement 2.

The modification of the starter 3b is to change the pull-in winding 9b of the engagement relay 7b in such a way that the same force-travel characteristic curve is ensured as in the case of an engagement relay 7 according to FIG. 1, but a higher current intensity of the relay current I _r 3 is necessary for this. As already mentioned, this is done by reducing the number of turns of the pull-in winding 9b while simultaneously increasing the conductor cross section.

As in the previous exemplary embodiments, the pull-in winding 9b is connected in series with the excitation winding 29 and the armature winding 27 in the same way. Due to the increased current requirement of the engaging relay 7b, which, according to the circuit, also "flows" over the excitation winding 29 and the armature windings 27, it is advantageously possible for the armature of the starter 3b. To have a greatly reduced speed during the engagement process of the drive pinion 21 in the ring gear 6 rotates. Due to this advantageous embodiment, the single-track spring 20, which is shown in FIG. 1, can be omitted in this third exemplary embodiment, and the steep thread 24 can also be dispensed with, that is, the single-track gear 52 can be omitted. However, it must be ensured that the drive pinion 21 continues to move axially on the rotor shaft 22. remains slidable, but suitable measures must be taken so that the drive pinion 21 is forcibly rotated when the armature rotates.

In order to be able to implement this exemplary embodiment in practice, it is necessary to design the drive output stage (not shown) of the control device 2b with an increased current carrying capacity.

The mode of operation of this third exemplary embodiment results from the foregoing in such a way that when the start switch 4 is actuated, the engagement relay 7b is actuated in a known manner, so that the axial movement of the drive pinion 21 takes place. The engagement of the drive pinion 21 in the toothed ring 6 in a tooth-on-tooth position is then made possible in that the armature 25 of the starter 3b rotates at a reduced speed during the periods 40 and 41 by the relay current I _r3 provided via the control device 2b . After the drive pinion 21 has been brought fully into engagement with the ring gear 6 and the relay armature 8 has been pulled completely into the pull-in winding 9b, the contact bridge 10 is closed via the mechanical connection to the engagement relay 7- shown in dashed lines. The third time period 42 begins when the contact bridge 10 is closed. The full battery voltage is applied to the excitation winding 29 and the armature winding 27 via the contact bridge 10, so that the motor current I _m 3 can increase to its nominal value. Due to the "flowing" rated motor current in the third time segment, the drive pinion 21 rotates at the speed that is necessary to turn an internal combustion engine (not shown here) via the ring gear 6.

When the starting process has ended, the drive pinion 21 is sensed in a known manner by the roller freewheel. As already mentioned, the mechanical components are returned to their starting position and the relay current and the motor current are switched off.

The fourth exemplary embodiment of the circuit arrangement shown in FIG. 7 differs with respect to the first exemplary embodiment according to FIG. 1 by an expanded control device 2c and a modified starter 3c.

The starter 3c here has a connection 38 which forms a bypass to the contact bridge 10 in connection with the additional output 39 of the control device 2c, the connection 38 being part of the contact bridge 10, so that advantageously no additional terminal on the starter 3c is necessary . The output 39 is connected within the control device 2c to a further control output stage, which is decoupled from the output which controls the engagement relay 7.

The resulting functioning of the starter device lc results in an advantageous manner in that the engagement relay 7 is energized by closing the start switch 4, as a result of which the engagement process of the drive pinion 21 in the gearwheel wreath 6 is initiated. The excitation winding 29 and the armature windings 27 are supplied with current by means of the additional control output stage of the control device 2c. The motor current I ^ provided via the additional control output stage at the output 39 of the control device 2c causes the armature 25 to rotate at a reduced speed.

Such a current profile of the motor current I _{4 is} shown in FIG. It can be seen that during the first time interval 40, the engagement relay 7 is energized in a known manner, while the starter motor remains switched off. Only during the second time period 41, while the engagement relay 7 is operated with reduced power, is the control device 2c providing a low motor current I ^. After the drive pinion 21 is in engagement with the ring gear 6, the motor current I _m4 is increased at the beginning of the third time period 42 by closing the contact bridge 10, so that the armature 25 rotates at the nominal speed, the drive pinion 21 attached to the rotor shaft 22 drives the ring gear 6 at the rotor speed.

When the starting process is complete, the drive pinion 21 is disengaged from the ring gear 6 in a known manner, and all mechanical components continue to move back to their starting positions, the relay current and the motor current being switched off.

It is clear that the circuit arrangement in the fourth exemplary embodiment is not just a temporal che decoupling of the axial and rotary movement of the drive pinion 21, but also enables a force decoupling.

It is thereby advantageously possible to apply a high axial force by means of the engagement relay 7 to engage the drive pinion 21 in the ring gear 6, and at the same time to reduce the drive torque of the armature 25 by reducing the motor current I _m4 . It is thereby possible to reduce the wear between drive pinion 21 and ring gear 6 to a minimum.

In summary, it can be stated that the first and second exemplary embodiments differ only in the differing supply of current, the relay voltage being pulse-width-modulated in the first exemplary embodiment and the relay current in the second exemplary embodiment being able to be influenced by a two-point controller.

A modified embodiment of the starter is provided for each of the third and fourth exemplary embodiments. In addition, the control devices 2b and 2c differ from each other. The control device 2b is characterized by an increased current carrying capacity of the control output stage, whereas the control device 2b has an additional control output stage for the power supply of the starter motor.

However, it should be expressly pointed out that the control devices in the third and fourth exemplary embodiments either use a pulse-width-modulated relay voltage or a Provide controllable current. A combination of the two current variants provided is also conceivable for the fourth exemplary embodiment.

Furthermore, a device is conceivable that regulates or controls the relay and / or motor current depending on the state. Such state variables can be, for example, the engagement relay temperature or the temperature of the armature winding.

The four exemplary embodiments mentioned can include a delay circuit, not shown here. This delay circuit makes it possible to block the starting device after a false start of the internal combustion engine, so that before a further starting process it is ensured that the drive pinion 21 and the ring gear 6 are no longer rotating.

After all, it can be seen that the circuit arrangement according to the invention is suitable for minimizing wear on the drive pinion 21 and ring gear 6, which results in an extension of the life of the starter device by a factor of 5 to 10 times. At the same time, the circuit arrangement enables noise reduction when the drive pinion 21 is engaged in the ring gear 6, since "ratcheting" is prevented.

A major advantage of the circuit arrangement according to the invention results from the fact that no significant mechanical changes have to be made to the starter.

Claims

Expectations

1. Circuit arrangement for a two-wheel engaging engagement relay of a starting device of an internal combustion engine, characterized by a control and regulating device (2) that a relay current after a first period (40) before the engagement of the two gears to a certain current value during a second Period (41) lowered.

2. Circuit arrangement according to claim 1, characterized in that the control and regulating device (2) in a third time period (42) increases the relay current (I _r ) to a predetermined value, the third time period (42) starting when the one Gear reaches the other.

3. Circuit arrangement according to one of the preceding claims, characterized in that the control and regulating device (2) comprises a current sensor (33) which detects the relay current.

4. Circuit arrangement according to claim 3, characterized in that the control and regulating device (2) controls the relay current depending on a measurement signal of the current sensor (33), preferably by means of a two-point regulator (37).

5. Circuit arrangement according to one of the preceding claims, characterized in that the engagement relay (7) in series with an armature and / or excitation winding (27, 29) is connected to a starting motor (51), which at least in the second and / or third time segment (42) is activated by the relay current with low power.

6. Circuit arrangement according to one of the preceding claims, characterized in that the control and regulating device (2) is designed such that it activates a starting motor (51) at least in the second and / or third time period (41, 42).

7. Circuit arrangement according to one of the preceding claims, characterized in that a control signal from the control and regulating device (2) to the engagement relay (7) is pulse width modulated.

8. Control and regulating device according to claim 7, characterized in that the lowering of the relay current is carried out by changing a duty ratio of the control signal.

9. Circuit arrangement according to claims 1 to 4, characterized in that a single-track device is provided which, at least in the second or third time period (41, 42), rotates one of the two gear wheels at a low speed relative to one another.

10. Circuit arrangement according to one of the preceding claims, characterized in that the control and regulating device (2) comprises a timer which prevents a restart of the starting device (1) before a predetermined time has elapsed after a last start.

11. Circuit arrangement according to one of the preceding claims, characterized in that the control and regulating device (2) controls the relay current depending on certain state variables.