Machine element or mechanism – Engine starters
Reexamination Certificate
2002-03-04
2004-07-20
Bucci, David A. (Department: 3682)
Machine element or mechanism
Engine starters
C074S00700R, C074S00700R, C123S179250
Reexamination Certificate
active
06763735
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a starter device for starting internal combustion engines.
Bendix starters are made known in the prior art. These Bendix starters comprise an electric starter motor with an armature shaft having a helically-grooved thread on one end. A tang shank is situated on this helically-grooved thread in rotatable and displaceable fashion; it is connected to a starting pinion via an overrunning clutch. The tang shaft moves into mesh with the overrunning clutch and the starting pinion when the starter motor is switched on. The force of inertia of the driven parts located on the helically-grooved thread of the armature shaft is thereby used, and the pinion is thereby engaged.
Moreover, a Bendix starter is made known in DE 24 39 981 A1 that includes a brake device to engage the driven elements. The brake device includes a ratchet sleeve having ratchet teeth that is frictionally engaged with the tang shaft. A pawl can be swung into the geometry of the ratchet teeth by means of an electromagnet, so that, when the pawl is swung into place and the starter motor is rotating, a force acts on the circumference of the tang shaft. In cooperation with the helically-grooved thread, a propulsive power is thereby produced, with which the pinion can be engaged in a ring gear of an internal combustion engine. When the starter device is switched on, the electromagnet is switched on first; as a result, an ignition armature is pushed out of the electromagnet, which causes the pawl to swing into the ratchet teeth. As the stroke movement of the ignition armature continues, two relay contacts are closed, which causes full battery current to flow to the starter motor, the starting pinion is moved into mesh and engages and, finally, the internal combustion engine is started. The pawl is also used to prevent the starting pinion from disengaging if the loads on the ring gear of the internal combustion engine fluctuate.
The starter device disclosed in DE 24 39 981 A1 has the disadvantage that, in addition to the actual ignition switch located on the instrument panel of the vehicle, further contacts located in the starter device are required to allow full battery current to flow to the starter motor. Furthermore, when space is very tight, the electromagnet is accommodated in the drive-end bearing of the starter device. This makes a side opening in the drive-end bearing necessary. In addition, this side opening must be closed by means of a separate cover.
SUMMARY OF THE INVENTION
Using the device according to the invention, it is possible to actuate a brake device without a second switch, however. By actuating the brake device by means of a stator or rotor, no further electrical components are needed for switching. This further results in the possibility of designing the starter largely coaxial in its internal construction. Fewer parts are required which enables the device to be realized with greater ease, reliability and cost-effectiveness.
If the change in position of a starter component is used to actuate the brake device, a solenoid or a rotary magnet can be realized, for example, by means of the interaction between rotor and stator. The rotor and the stator thereby perform a double function. On the one hand, the stator and the rotor, when supplied with full battery current, effect a rotary motion of the rotor or the armature shaft and, therefore, of the starting pinion, and therefore represent the drive. On the other hand, they perform the switching function for the brake device.
When the rotor and stator are located in suitable fashion relative to each other, the rotor or the stator can be either rotated or displaced in order to actuate the brake device. As a result of this change in position resulting from reaction power, a force can be transferred to the brake device that can be used to actuate the brake. Either the rotation of the pole tube or the stator, or its displacement, or the displacement of the rotor relative to the stator can thereby be used in advantageous fashion.
A reaction power or a reaction torque of a starter component can thereby be used to rotate a keyway element and, as a result, to press brake keys against a brake drum, by way of which a braking torque can be applied to the driven shaft.
According to another advantageous embodiment, it is possible to actuate a pawl by means of the change in position of one of the starter components and thereby produce a braking torque on the rotating driven shaft in cooperation with a disk and a positive engagement occurring between pawl and disk. A simple and lightweight braking mechanism can thereby be realized.
A frictional engagement between disk and driven shaft ensures a force transmission between driven shaft and disk that is easy on the disk and the pawl.
The frictional engagement between driven shaft and disk further makes it possible for the pinion to rotate despite a tooth-on-tooth connection between the ring gear of the internal combustion engine and the driven element designed as pinion.
A disposition of a disengagement spring that is favorable in terms of installation space is given, on the one hand, by means of support on the drive-end housing side and, on the other hand, by means of support on the driven shaft.
A very good sealing of the starter or the starter motor is given when the pole tube is enclosed by a separate starter motor housing. Furthermore, the base of the pot-like starter motor housing can be designed as a bearing receptacle and, as a result, the pole tube can be supported in bearings in the starter motor housing.
The bearing element for supporting the pole tube in the starter motor housing can also be designed as a bearing for the rotor.
In order to reverse the disengagement prevention by the pawl or one or more keys toward the end of the starting procedure so that the pinion can disengage, a spring element is to be provided on the starter component changing its position that counteracts the change in position in order to actuate the brake.
REFERENCES:
patent: 3741021 (1973-06-01), Parsons
patent: 4326429 (1982-04-01), Mortensen
patent: 4327300 (1982-04-01), Hoven
patent: 4346615 (1982-08-01), Yoneda et al.
patent: 4460838 (1984-07-01), Ulicny
patent: 4506162 (1985-03-01), Bolenz et al.
patent: 4922868 (1990-05-01), Ohkanda
patent: 5255644 (1993-10-01), Mills et al.
patent: 5291861 (1994-03-01), Bartlett
patent: 5596902 (1997-01-01), McMillen
patent: 5617758 (1997-04-01), Nishida
patent: 5760485 (1998-06-01), Ohmi
patent: 24 39 981 (1976-03-01), None
Braun Hans
Hartmann Sven
Nguyen Ngoc-Thach
Siems Hans-Dieter
Bucci David A.
Hansen Colby
Robert & Bosch GmbH
Striker Michael J.
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