EP1236890A2 - Inertia gear drive starter - Google Patents

Abstract

Starter motor (2), for an internal combustion motor, has a drive shaft (3) with a coupled gearing (5) and preferably a planetary gear with a freewheel (11) and a coupled drive take-off shaft (12). A single-track gearing (17) to operate the starter pinion (16) is coupled to the take-off shaft, with a coarse screw thread (15), toothed brake disk (18) and brake lock (19). The brake lock is a bi stable brake rocker, automatically positioned between two end settings which give a locking and a release action, held in the end positions by a bi stable snap spring.

Description

The invention relates to a brake screw drive starter for starting of internal combustion engines with those specified in the preamble of claim 1 Features.

Such a brake screw drive starter is known from DE 24 39 981 A1. It has a starter motor with a drive shaft with which a Gearbox - usually a planetary gearbox - is connected to freewheel. A drive shaft, on which a so-called Single track gear is arranged for the starter pinion. This single-track transmission has a high helix thread, a toothed brake disc and a brake locking element on.

In the starter according to the aforementioned document DE 24 39 981 A1 the brake locking member comprises a locking sleeve with locking teeth which are frictionally engaged with the driving shaft for the Starter pinion is connected. A pawl is through an electromagnet can be swiveled into the geometry of the locking teeth so that when swiveled in Pawl and rotating starter motor on the circumference of the Entrainment a force works. In cooperation with the steep thread this results in a propulsive force with which the pinion fits into one ring gear coupled to the crankshaft of an internal combustion engine can be tracked.

When the starter is activated, the electromagnet acts as an actuator energized, a magnetic armature pushed out of it and the Pawl pivoted into the ratchet teeth. With the further lifting movement of the magnet armature, two relay contacts are closed, thereby the starter motor is energized, the starter pinion is engaged and engaged finally the internal combustion engine started by turning it on. The The pawl is also used for changing loads on Toothed ring of the internal combustion engine to trace the pinion prevent.

The starter disclosed in DE 24 39 981 A1 has the disadvantage that in addition to the actual start switch located on the dashboard of the vehicle further contacts arranged in the starting device for energizing of the starter motor are required. It is also very cramped Space of the electromagnet of the actuator in the drive bearing of the Starters. This makes a side opening in the drive bearing necessary. In addition, this side opening must be through a separate Cover to be closed.

In summary, the actuation of the prior art takes place mechanical toe-in function by a mechanical integrated in the starter Relay, which is usually also the switching function for the starter main current takes over. This relay is an actuator for controlling the input and Track function assigned. If there is - like modern starter constructions provide - the relay and motor components are spatially separated become, a second actuator for controlling the brake locking member of the starter is necessary.

Another particular problem with starters is the control system of disconnecting and switching off the starter. In this context electronic shutdown controls are now easy to implement, which is usually a speed signal as an input variable for the shutdown control use. Until reliable detection of the switch-off speed, the implementation of the corresponding signal and by a certain period of time inevitably goes off, which is the dead time of the shutdown control. This is on the temporal scale of the starting process is quite significant, which is reflected in this expresses that the internal combustion engine until the actual tracking and switching off is already running at a higher starting speed, which results in a increased overhaul speed of the pinion compared to the starter motor. This leads to increased stress on the between pinion and starter motor arranged freewheel and avoidable noise.

Based on the described disadvantages of the prior art the invention has for its object a brake screw drive starter to specify whose engagement and disengagement process in a reliable manner without Actuator is controllable.

This object is achieved by the in the characterizing part of claim 1 Features specified resolved, after which the brake locking member automatically between two bistable end positions, namely a release end position and a blocking end position is switchable. Preferably, the brake locking member be designed as a bistable brake rocker, which in turn by a bistable snap spring can be held in its end positions.

As can be seen from the subclaims 4 to 6, the actuation of the Brake locking member in the locking end position, preferably with the help of a inertia-controlled actuator. This can - such as in the older but later published application DE 100 16 706 A1 is specified - consist of a rotatably mounted stator tube, that when starting the starter motor due to the repulsive forces between the motor and stator is deflected about its tube axis. This Deflection movement is with the help of an actuator Transfer brake blocking element.

An alternative to this provides sub-claim 5, according to which the actuator for the brake locking member on the deflectable ring gear of the planetary gear the starter is arranged. Further details can be found in the description of the embodiment.

For the actuation of the brake locking member in the release end position is according to further preferred embodiments of the invention according to the Claims 7 to 10 a centrifugal opener, preferably on the single-track transmission, intended. This makes the pinion's rotation and speed immediate mechanically detected, so that the combustion engine during self-running with a correspondingly high speed of the pinion practically without time delay for signal processing from the centrifugal opener mechanically implemented and the brake locking member in the release end position can be transferred. This allows the pinion to run without time Disengage the delay, which is the period of "overtaking" in the Starter gear train significantly reduced.

• Es ermöglicht die Selbstschaltung des Ein- und Ausspurvorganges ohne Aktuator.
• Damit ist die elektrische Schaltfunktion für den Starter von der mechanischen Schaltfunktion für das Ein- und Ausspuren problemlos örtlich zu trennen.
• Die Steuerung von Ein- und Ausspuren wird rein mechanisch vorgenommen.
• Der Selbstlauf der angedrehten Verbrennungsmaschine kann unmittelbar das selbsttätige Ausspuren steuern.
• Durch die Bistabilität des Brems-Sperrgliedes sind die Freigabe- und Sperr-Endlage und der Schaltvorgang dazwischen jeweils in Ablauf und Zeitpunkt eindeutig definiert.

In summary, the automatic, bistable brake locking element according to the invention results in a number of advantages:

• It enables automatic engagement and disengagement without an actuator.
• This means that the electrical switching function for the starter can easily be separated from the mechanical switching function for engaging and disengaging.
• The control of in and out tracks is done purely mechanically.
• The self-running of the turned-on internal combustion engine can directly control the automatic disengagement.
• Due to the bistability of the brake blocking element, the release and blocking end positions and the switching process between them are clearly defined in terms of sequence and time.

Fig. 1

einen Teilaxialschnitt durch einen Starter,

Fig. 2

eine schematische Axialansicht der Bremsvorrichtung mit Zahn-Bremsscheibe und Brems-Sperrglied,

Fig. 3

eine schematische Axialansicht des Planetengetriebes des Starters,

Fig. 4

eine ausschnittsweise Detailansicht des Brems-Sperrgliedes aus Pfeilrichtung IV nach Fig. 2, und

Fig. 5 und 6

ausschnittsweise Detailschnitte durch Fliehkraftöffner in zwei unterschiedlichen Ausführungsformen.

Further features, details and advantages of the invention can be found in the following description, in which an exemplary embodiment is explained in more detail with reference to the accompanying drawings. Show it:

Fig. 1

a partial axial section through a starter,

Fig. 2

1 shows a schematic axial view of the brake device with toothed brake disk and brake locking member,

Fig. 3

1 shows a schematic axial view of the planetary gear of the starter,

Fig. 4

a fragmentary detailed view of the brake locking member from the direction of arrow IV of FIG. 2, and

5 and 6

cutouts of detail cuts by centrifugal force openers in two different embodiments

1 shows in section those relevant to the present invention Components of a brake screw drive starter, the motor housing with 1 is designated. The starter motor 2 housed therein is only schematic indicated. Whose drive shaft 3 carries the sun gear 4 one Planetary gear 5, the so-called "countershaft gear" in the starter acts. With the sun gear 4 mesh several planet gears 6, of which only one is shown in FIG. 1 (and also 3). Radially outside the planetary gear 5 from an essentially stationary ring gear 7 limited, in which the planet gears 6 roll. The ring gear 7 is in a so-called intermediate storage 8 in a manner to be discussed in more detail stored, which is arranged stationary and rotatably on the motor housing 1.

The planet gears 6 are rotatably supported around the motor axis Planet carrier 9 held by the latter of the number of planet gears 6 correspondingly has several stub axles 10 on which the planet gears 6 are each rotatably mounted.

A conventionally constructed freewheel 11 is mounted on the planet carrier 9 a coaxial to the drive shaft 3 mounted in a drive bearing cover 13 Output shaft 12 drives. A so-called sits on the output shaft 12 Driver shaft 14, which is connected to the output shaft 12 via a helical thread 15 is coupled. On the side of the driver shaft facing away from the starter motor 2 14, a starter pinion 16 is formed, which is not closer to one illustrated ring gear on the crankshaft of the internal combustion engine to be started can be brought in and out of engagement.

The necessary entry and exit movement is made with the help of the steep thread 15 accomplished, in the present case a brake screw drive starter the single-track gear 17 next to the steep thread 15 a toothed brake disk 18 seated in a rotationally fixed manner on the driving shaft 14 and radially outside of it a brake rocker that can be brought into engagement with it 19, the structure and function of which are described in more detail below becomes.

To actuate the brake rocker 19 in the direction of the locking end position is one Actuating rod 20 extending parallel to the motor axis is provided is fixed in the ring gear 7 and the intermediate bearing 8 via an elongated hole 21 reaches through.

Finally, on the driving shaft 14 on its side facing away from the starter pinion 16 End a centrifugal opener 22 is provided with which the brake rocker 19 in the direction of their release end position to be explained in more detail Way is switchable.

2 and 4, the brake rocker 19 consists of a elongated sheet metal part, which is bent several times over its length is. At one end, three punched-out tabs lie side by side 23, 24, 25 a hinge 26 with which the brake rocker 19 on a pivot pin 27 anchored in the intermediate storage 8 is. In front of the opposite end, a ratchet tooth 28 is punched out and folded in the direction of the toothed brake disk 18. On the hinge 26 facing end 29 of the brake rocker 19 also engages in a bearing pin 30 pivotable snap spring 31. Brake rocker 19 and snap spring 31 form a kinematic system that is two bistable Has end positions, namely that shown in Fig. 2 with solid lines Release end position and the blocked end position shown in dashed lines. In the release end position, the brake rocker 19 is at its end 29 the operating rod 20.

The function of the brake screw drive starter for engaging the starter pinion 16 can now be explained as follows:

By activating the starter, its starter motor 2 is started, whereby the planetary gear 5 is set in rotation. By the Rolling the planet gears 6 in the ring gear 7 and the start of the rotary movement the rotatably mounted ring gear 7 against the direction of rotation Planet carrier 9 is subjected to a torque. This leads to a Rotary movement of the ring gear 7 in the direction of rotation B, so that in the ring gear 7 stored confirmation rod 20 is deflected accordingly. The Rotary movement of the ring gear 7 is by a damping device 32 limited. This is due to a short circumferential distance of the interim storage facility 8 running storage pockets 33 and elastomer inserted therein Damping body 34 formed, each radially between them Include driver nose 35 formed on the outside of ring gear 7. In the Rotation of the ring gear 7 is that lying in the direction of rotation B. Damping body 34 compresses and thus builds a counterforce against the ring gear rotation.

The deflection A of the actuating rod generated by the ring gear rotation 20 is transferred to the bistable brake rocker 19 to the side from the release end position into the blocking end position shown in dashed lines in FIG. 2 is transferred. The locking tooth 28 of the brake rocker engages in this 19 behind the locking edge 36 of one of the teeth 37 of the tooth brake disc 18 and thus blocks their rotational movement. Since the rotation of the Starter motor 2 via the planetary gear 5 and the freewheel 11 on the Output shaft 12 of the starter transmits, finds a relative rotation between the output shaft 12 and the stationary entrained shaft 14 instead. As a result, the latter is on the steep thread 15 in the engagement direction E against the effect of a track spring, not shown relocated. The starter pinion 16 meshes with the corresponding ring gear the combustion machine and can turn it on. By relocating of the driving shaft 14 in the meshing direction E the brake rocker slips 19 from the toothed brake disc 18 and lays down due to the effect the snap spring 31 behind the toothed brake disc 18, as shown in FIG. 2 dotted is indicated. This is an unintentional tracing of the Starter pinion 16 initially blocked under the influence of the track spring.

Disengagement is only necessary if the combustion engine is independent running. This condition is indicated within the braking device the aforementioned centrifugal opener 22 detects and immediately in an application the brake rocker 19 implemented in the direction of the release end position.

For this purpose, the centrifugal force opener 22 has a flange flanged to the driving shaft 14 Holding plate 38 on which a carrier 39 for a slidable therein guided, essentially bolt-shaped mass element 40 holds. As is clear from FIG. 5, there is a bearing opening 41 between them for the mass element 40 having cranked bearing arm 42 of the Carrier 39 and one arranged at the inner end of the mass element 40, circumferential ring projection 43 a centrifugal force return spring 44th clamped, which acts on the mass element 40 radially inwards. In its rest position is on the bracket 38 (Fig. 5).

The mass element 40 is now counter to the return spring 44 with increasing Speed of the driving shaft 14 shifted radially outwards. As with the self-running of the internal combustion engine turned on with the starter the speed of the starter pinion 16 and thus the driving shaft 14 increased suddenly with activation of the freewheel 11, that is Mass element 40 shifted outwards accordingly. It meets the Brake rocker 19 and switches this from the stable locking end position in the also stable release end position. The brake rocker 10 disengages with the tooth brake disc 18, whereby the not shown Ausspurfeder the driver shaft 14 against the starter pinion 16 shift the engagement direction E and ensure that the pinion 16 is disengaged can.

6 shows an alternative embodiment of a centrifugal force opener 22 '. Here, the mass element 40 'is a circular arc, one elongated body executed, the radial in the middle has inwardly facing storage pot 45. This is in a bearing recess 46 of the driving shaft 14 guided radially. To secure of the mass element 40 'is one in the inner opening of the bearing pot 45 arranged, the bottom 49 penetrating stop screw 47 provided in a blind thread 50 in the front end of the bearing recess 46 is attached. Between the head 48 of the stop screw 47 and the bottom 49 of the bearing cup 45 is in turn a return spring 44 'clamped, the mass element 40' radially inward against the centrifugal force occurs.

Due to the elongated shape of the mass element 40 ', the actuation the brake rocker 19 executed less hard and suddenly.

Claims (10)

Comprehensive brake screw drive starter for starting internal combustion engines a starter motor (2) with a drive shaft (3), an associated gear (5), preferably planetary gear, with freewheel (11), an output shaft (12) coupled to the freewheel (11), a single-track gear (17) coupled to the output shaft (12) with steep thread (15), toothed brake disc (18) and brake locking member (19), and a starter pinion (16) which can be actuated by the single-track gear (17), characterized in that the brake blocking element (19) can be switched automatically between two bistable end positions, namely a release end position and a blocking end position. Starter according to claim 1, characterized in that the brake locking member is designed as a bistable brake rocker (19). Starter according to claim 1 or 2, characterized in that the brake locking member (19) is stable in its end positions by a bistable snap spring (31). Starter according to one of claims 1 to 3, characterized in that the brake locking member (19) is actuated into the locked end position by an inertia-controlled actuator (20). Starter according to claim 4, characterized in that the actuating member (20) is arranged on the ring gear (7) of the planetary gear (5), the ring gear (7) being deflectable about its axis of rotation under the influence of the internal inertial forces and the actuation of the braking Locking member (19) by the deflection movement. Starter according to claim 5, characterized in that the ring gear (7) is provided with a damping (34) with respect to its deflection movement. Starter according to one of claims 1 to 6, characterized in that the brake locking member (19) is actuated into the release end position by a centrifugal force opener (22, 22 '). Starter according to claim 7, characterized in that the centrifugal force opener (22, 22 ') is arranged on the single-track gear (17). Starter according to claim 8, characterized in that the centrifugal opener (22, 22 ') has a mass element (40, 40') which is spring-loaded against the centrifugal force and which, in its deflected position, acts on the brake locking member (19) in the direction of the release end position , Starter according to Claim 9, characterized in that the mass element (40 ') has a shape which is elongated in a circular arc in the direction of rotation of the centrifugal force opener (22').

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