EP1322861A2

EP1322861A2 - Starting device for internal combustion engines

Info

Publication number: EP1322861A2
Application number: EP01969267A
Authority: EP
Inventors: Karl-Otto Schmidt; Hartmut Wanner; Uwe Daurer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2000-09-22
Filing date: 2001-08-31
Publication date: 2003-07-02
Anticipated expiration: 2021-08-31
Also published as: DE10046987A1; WO2002025105A2; DE50109711D1; ES2259672T3; EP1322861B1; WO2002025105A3

Abstract

The invention relates to a starting device for internal combustion engines, comprising a starter motor (11), whose starter pinion engages in the ring gear of an internal combustion engine with the aid of an engaging relay (19) which also switches on the starter motor towards the end of its stroke movement by means of a switching contact (24). The engaging relay (19) is also provided with a pull-in winding (22) and a hold-in winding (23). In order to prevent grating of the starter pinion in the ring gear of the internal combustion engine during the engagement procedure, the pulling force of the pull-in relay during forward engagement of the starter pinion is reduced due to the fact that the hold-in winding (23) is mounted in series with a control switch element (28), which can be set to the guiding mode by a timing member (29) that is connected to a terminal (50) conducting the start signal so that the hold-in winding (23) is switched on in a delayed manner in relation to the pull-in winding (22).

Description

Starting device for internal combustion engines

The invention relates to a starting device for starting internal combustion engines' according to the preamble of claim 1.

State of the art

In so-called push-screw drive starters according to EP-PS 518 895, it is known that the starter pinion is operated by a so-called manual start switch

Engagement relay with a pull-in and holding winding to a ring gear of the internal combustion engine and then engaged there and then the electric starter motor is energized via a switch contact of the engagement relay. The relay armature of the engagement relay is moved axially and the armature movement is transmitted via a single-lever and a single spring to a freewheel gear which carries the pinion at the front. Towards the end of the armature path, the circuit of the starter motor is also closed via the switch contact of the engagement relay and thus the

Rotation of the starter motor initiated with full force.

Such starting devices have a tendency to ratchet, particularly in the case of powerful accumulator batteries in the vehicle. The Due to the armature movement of the engagement relay and the mass inertia, the toe-in spring is tensioned in a dynamic process before the starter pinion is pressed against the end face of the ring gear in a tooth-on-tooth position during toe-in. At the end of the anchor movement, the

Circuit of the starter motor is closed via the switching contact of the engagement relay and the pinion, which has not yet been engaged by inertia or is not yet in full contact with the ring gear, is driven by the starter motor with great torque, whereby it mills over the end faces of the teeth of the ring gear. This not only leads to a false start of the internal combustion engine, but in particular to increased wear of the pinion and the ring gear. It is also disadvantageous that the delayed but progressively dynamic engagement process causes a high impact speed and the impact force of the pinion on the ring gear to cause a strong engagement impact with a correspondingly high level of material wear in this area.

The aim of the present solution is to influence the single-track dynamics in such a way that ratcheting of the starter pinion on the ring gear of the internal combustion engine is prevented as reliably as possible when the internal combustion engine starts.

Advantages of the invention

The starter device according to the invention with the features mentioned in the characterizing part of patent claim 1 has the advantage over the prior art that when a start signal occurs, the starter pinion is pretensioned to the ring gear with reduced pull-in force and therefore with less dynamics by a delayed switching on of the holding winding relative to the pull-in winding , First At the end of the time delay, the holding coil is additionally energized and the starter pinion is now pressed into the ring gear with full engagement force by the preloaded engagement spring. The switching contact of the engagement relay is only now closed and the starter motor is closed

Starting the engine fully energized. In addition, the pull-in winding is switched off when the switch contact closes. In addition, due to the reduced force of the engagement relay, the starting device according to the invention results in reduced material wear on the pinion and ring gear and a reduced engagement. In a tooth-on-tooth position, the meshing pinion can also be rotated more reliably into the next tooth gap in the ring gear of the internal combustion engine due to the delayed starting motor.

The measures listed in the subclaims result in advantageous developments and improvements of the features specified in the main claim. Thus, the timing element is designed in the simplest form in the form of an RC element, preferably in the form of a series RC element, the resistance-capacitor connection being connected to the control connection of the control switching element switching the holding winding. The series RC element is connected in the simplest manner with its resistance to the control line carrying the start signal and the capacitor is connected to a ground connection of the starter device. Since the starting dynamics of the engagement relay are reduced with increasing temperatures, this can be compensated for in an advantageous manner in that the time delay for switching on the holding winding is reduced with increasing temperatures by the resistance of the RC element being an NTC resistor. In order to ensure, if necessary, short successive repetition starts, it is advisable to connect a discharge resistor in parallel to the capacitor of the RC element. Furthermore, for a rapid reversal of the control switching element from the locked state to the conductive

State when the holding winding is switched on with a delay in an advantageous manner upstream of the control connection a threshold switch, preferably a Z-diode. In this case, a transistor, preferably a field effect transistor, can be used as the control switching element. Alternatively, a thyristor or triac should be used.

The conventional starting devices can also be converted to the embodiment according to the invention in a relatively simple manner by replacing the engagement relay. In this case, the control switching element and the timing element are accommodated as a potted circuit module in the engagement relay. The circuit module has two connections for the switching path of the

Control switching element, which are connected between a magnetic core of the engagement relay which is at ground potential and the end of the holding winding facing away from the control line.

drawing

The invention is explained in more detail below with reference to the figures.

Show it

1 shows the mechanical structure of a starting device with engagement relay and starter motor, 2 shows the circuit structure of the starting device in a first embodiment of the solution according to the invention,

3 shows a diagram with the magnetic flooding at the engagement relay during a starting process,

4 shows the circuit structure of a second embodiment of the starting device and

Fig. 5 shows a circuit module.

Description of the embodiments

Fig. 1 shows schematically the mechanical structure of the starting device 10 according to the invention in the form of a push-screw starter for internal combustion engines. The starting device 10 has a starter motor 11, the output shaft 12 of which has a steep thread 13, which cooperates with a corresponding nut thread in a driving shaft 14. Alternatively, the output shaft 12 is driven by the starter motor 11 via an interposed planetary gear, not shown. The driver shaft 14 is fixedly connected to the outer ring of a freewheel 15, the inner ring of which carries a starter pinion 16 at the front. Starter pinion 16 and freewheel 15 are on the

Output shaft 12 is axially displaceable up to a stop 17. The starter pinion 16 is engaged in a ring gear 18 of the internal combustion engine. The axial displacement takes place with the aid of an engaging relay 19, the relay armature, not shown, of a bell crank 20 and one

Track spring 21 engages the freewheel 15.

FIG. 2 shows the circuit structure of the starter device according to FIG. 1. It can be seen there that the engagement relay 19 has a pull-in winding 22 and a holding winding 23 as well as one Has switching contact 24, which is located in the main circuit 36 of the starter motor 11. The engagement relay 19 has three, i connection terminals 30, 45 and 50, and its housing is at ground potential. The switch contact 24 lies with its connecting terminal 30 on the positive connection of an accumulator battery 25 of the motor vehicle, which is connected to ground with its negative connection. The switch contact 24 is also connected via the terminal 45 to the starter motor 11, the other connection of which is also connected to ground. To control the engaging relay 19, pull-in and holding windings 22, 23 are connected at one end together via the connecting terminal 50 to a control line 26, via which, in the example, a start signal to the starter device is received via a manual start switch 27 located at the plus potential of the motor vehicle electrical system , The other end of the

Pull-in winding 22 is connected internally to the connecting terminal 45 and is thus connected between the starter switch 24 and starter motor 11 with its main circuit.

To avoid so-called ratcheting of the

Starter pinion 16 on the ring gear 18 during the starting process, the engagement relay 19 for advancing the starter pinion 16 should initially only be operated with a reduced magnetic flux. For this purpose, the holding winding 23 is connected in series with a control switching element 28, which can be controlled in the conductive state by a timing element 29 acted upon by the start signal. 2, the control switching element 28 is a field effect transistor and the timing element 29 consists of a series RC element. The timing element 29 is connected here via a resistor 31 to the terminal 50 carrying the start signal, and is connected to ground via a capacitor 32. The connection 33 between the resistor 31 and the capacitor 32 of the timing element 29 is connected to the control connection 34 of the control switching element 28. whose switching path lies between the end of the holding winding 23 facing away from the control line 26 and a ground connection. The resistor 31 is designed here as an NTC resistor, the mode of operation of which is explained in more detail below with reference to FIG. 3. Furthermore, in

If necessary, a dashed-line discharge resistor 35 is arranged parallel to the capacitor 32 of the timing element 29.

Fig. 3 shows the magnetic flux of the engagement relay

19 when applying a start signal via the control line 26 during a starting process; specifically in diagram a) during a cold start in the normal temperature range and in diagram b) during a warm start at elevated temperature at the engagement relay 19. The mode of operation of the starting device according to the invention of the first exemplary embodiment will now be explained in more detail with the aid of FIGS.

In the idle state, the start switch 27 is open and the engagement relay 19 in the rest position according to FIGS. 1 and 2. The capacitor 32 of the timing element 29 is discharged and the switching path of the control switching element 28 is thus blocked.

When the start switch 27 is closed at the time t1, a start signal reaches the terminal 50 of the

Engagement relay 19. A current now flows through the pull-in winding 22 to terminal 45 and from there via the starter motor 11 to ground. The magnetic flux φ 22 thereby generated in the engagement relay 19 now causes an axial movement of the relay armature, as a result of which the lever is turned

20 and via the engagement spring 21, the starter pinion 16 is initially pre-engaged to the ring gear 18 of the internal combustion engine. When the starter pinion 16 is in a tooth-on-gap position relative to the ring gear 18, the pinion immediately engages in the ring gear 18. At the same time with the creation of the Start signal at terminal 50 also activates the timer 29, the capacitor 32 is charged via the resistor 21. After the delay time that can be set by the RC timer 29, the potential on the capacitor 32 has risen to such an extent that the switching path of the control switching element 28 is now reversed from the blocking state into the conductive state at the time t2. Thus, a current flows to ground via the holding winding 23, which generates a further flow φ 23. The armature of the engaging relay 19 will therefore engage the starter pinion 16 with full force of the total flow (φ 22 + φ 23) up to the stop 17 in the ring gear 18 from time t2. Towards the end of the armature stroke, the switching contact 24 of the engagement relay 19 is now also closed at the time t3, so that the

Starter motor 11 is switched on via its main circuit 36 and the output shaft 12 and starter pinion 16 rotate at full power. When the switching contact 24 closes, the plus potential reaches terminal 45, so that the engagement winding 22 is bridged. Until the opening of the

Start switch 27 at time t4, the engagement relay 19 is now held in its engagement position only via the holding winding 23 with the flux φ 23.

In order to avoid ratcheting of the starter pinion 16 on the toothed wheel 18 during the engagement process in a tooth-on-tooth position, the toe-in force and thus a tensioning caused by the mass inertia of the pinion 16 is reduced by the reduced flow φ 22 until time t2 Track spring reduced. Only after applying the pinion

16 on the ring gear 18, the holding winding 23 and then the starter motor 11 are switched on via the timing element 29 with the control switching element 28. As a result, the pinion 16 is now engaged in the ring gear 18 with the full force of the engagement relay 19 and the starter motor 11. When the engagement relay 19 is switched off, opening the start switch 27 _. the plus potential at terminal 50 is switched off. However, since the switch contact 24 of the engagement relay 19 is still closed at this time, in addition to the main current for the starter motor 11, a current also flows via the terminal 45 to the pull-in winding 22, which is now connected in series with the holding winding 23 and the control switching element 28 against ground is. Since the pull-in and holding windings have the same number of turns and in this case are flowed through by the same current, their flows are directed in opposite directions and cancel each other out. Thus, the relay armature is moved back into its rest position by its return spring, not shown, and it opens the switching contact 24. The permanent magnet excited

Starter motor 11 is subsequently braked electrodynamically via this circuit. The capacitor 32 of the timing element 29 then discharges via the control path ^{• of} the control switching element 28 or via the discharge resistor 35 and the control switching element 28 is controlled back into the blocking state.

Since in a so-called warm start with hot starter relay 19, the magnetic flux with increasing ohmic resistance of the pull-in and hold-in winding decreases, this is compensated by the effect of the NTC resistor 31 largely characterized ^", that with increasing temperature of the capacitor 32 of the RC timing element 29 charged faster and thus the time delay for switching on the holding winding 23 is reduced - as can be seen from the diagram b) of Fig. 3. Even if the engagement process of the starter pinion 16 has not yet taken place at the time t2 'when the holding winding 23 was switched on , ratcheting is also avoided here due to the reduced total flooding on the engagement relay 19. The engagement spring 21 is now biased accordingly slower and with the help of the steep thread 13, the engagement in the ring gear 18 is supported without ratcheting. Even now, the main circuit of the starter motor is closed by the switching contact 24 of the engagement relay 19 at the time t3 'only after the streaking, so that the starting force of the starter motor 11 is only fully effective in this case after the pinion 16 has been applied or engaged on the ring gear 18 becomes.

Fig. 4 shows the circuit structure of another

Embodiment of the starting device according to the invention, the same parts being provided with the same reference numbers.

In this example, the control switching element 28a connected in series with the holding winding 23 is a thyristor, the control connection 34a of which is connected via a Zener diode 37 to the RC connection 33 of the timing element 29 in order to achieve an adjustable time switching point. Since the thyristor 28a is kept in the conductive state after the ignition by the current drawn through the holding winding 23, the thyristor arrives at a time delay when the start signal is applied to terminal 50 by the timing element 29 when the tens voltage of the Zener diode 37 is reached current-carrying state. After the start signal has been switched off and the switch contact 24 has subsequently been opened, the thyristor 28a then automatically enters the blocking state only after the EMF of the starter motor 11 has decayed. The resistor 31 of the timing element 29 is connected here on the input side to the anode of the thyristor 28a. As a result, the capacitor 32 of the timer 29 can already during the

Discharge the start process between t3 and t4 via resistor 31 and the switching path of thyristor 28a.

This solution also has the advantage that the thyristor 28a with the Zener diode and the timing element 29 become one Embedding the encapsulated circuit module 38 that can be accommodated in the engagement relay 19. In Fig. 5, such a circuit module 38 is depicted in spatial form. It ^" only requires two connection boards 39 and 40, the connection board 39 as the cathode connection of the thyristor 28a being screwed to the magnetic core of the engagement relay 19 as a ground contact with a screw 41 indicated by a broken line, and the other connection board 40 as the anode connection of the thyristor 28a to the wire end 23a of the holding winding 23 is welded.

In the same way, the control switching element 28 and the timing element 29 from FIG. 2 can also be integrated in a circuit module that is to be accommodated in the engagement relay 19. In this case, however, a third connection is made on

Circuit module required, which is to be connected to the terminal 50 of the engagement relay 19 to apply a start signal. As an alternative to the field effect transistor 28 or thyristor 28a, a triac or a switching transistor designed for the current of the holding winding 23 can also be used as the control switch. In all cases, the delayed switching on of the holding winding 23 prevents the starter pinion from ratcheting on the ring gear, the engagement safety being maintained by the force of the engagement spring when the armature of the engagement relay 19 is retracted, and the wear on the ring gear and pinion is significantly reduced.

Claims

Expectations

1. Starting device for internal combustion engines with a starter motor (11), the starter pinion (16) with the help of an engagement relay (19) and an intermediate engagement spring (21) in a ring gear (18)

Internal combustion engine is able to track, the engagement relay having a switching contact (24) located in the main circuit (36) of the starter motor, which switches on the starter motor towards the end of the stroke movement of the engagement relay, and wherein the engagement relay also has one

Has pull-in winding (22) and a holding winding (23) which are acted upon by a start signal via a control line (26) during the starting process and whose pull-in winding can also be switched off when the starter motor is switched on, characterized in that the holding winding (23) with a control switching element

(28) is connected in series, which is connected via a timer connected to a connection carrying the start signal

(29) is controllable in the conductive state.

2. Starting device according to claim 1, characterized in that the timing element (29) is an RC element.

3. Starting device according to claim 2, characterized in that the timing element (29) is a series RC element whose Resistor-capacitor connection (33) is connected to the control connection (34) of the control switching element (28).

5 4. Starting device according to claim 3, characterized in that the series RC element with its resistor (31) with the control signal leading the start signal (26) and the capacitor (32) is connected to a ground connection.

10 5. Starting device according to claim 4, characterized in that the resistor (31) of the RC timer (29) is an NTC resistor.

6. Starting device according to one of claims 3, 4 or 5, 15. characterized in that parallel to the capacitor

(32) of the RC timer (29) is connected to a discharge resistor (35).

7. Starting device according to one of the preceding claims,

20 characterized in that the control connection (34a) of the

Control switching element (28a) is a threshold switch (37), preferably a Z-diode upstream.

8. Starting device according to one of the preceding claims, 25 characterized in that the switching path of the

Control switching element (28) between the _. the control line (26) facing away from the end of the holding winding (23) and a ground connection.

30 9. Starting device according to claim 8, characterized in that the control switching element (28) is a transistor, preferably a field effect transistor.

10. Starting device according to claim 8, characterized in that the control switching element (28a) is a thyristor or triac.

11. Starting device according to one of the preceding claims, characterized in that the control switching element (28a) and the timing element (29) as a potted circuit module (38) in the Ξinrückrelais (19) housed and with the two connections (39, 40) of its switching path between one at ground potential

Magnetic core of the engagement relay (19) and the end of the holding winding (23) is connected.