Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1992-08-05
1994-02-01
Stephan, Steven L.
Electrical generator or motor structure
Dynamoelectric
Rotary
310 49A, 310156, 251 65, 25112911, H02K 106, F16K 3104
Patent
active
052834956
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention is based on a rotary actuator for setting the rotation angle of control elements, especially of a throttle device, which determines the flow cross-section in a line through which flow passes, for internal-combustion engines.
In a known rotary actuator of this type (DE 38 30 114 A1), the two stator poles for generating the magnetic restoring torque for the permanent-magnet rotor are constructed asymmetrically with a pole width, seen in the circumferential direction, deviating greatly from one another. The rotor poles, which are constructed as shell-shaped magnet segments, are arranged asymmetrically on the rotor and extend in each case over a circumferential angle of greater than 90.degree., the pole width, measured in the circumferential direction, of the stator pole having the smaller pole width having approximately the same angular extent as the rotor poles. The stator winding, through which DC current flows, engages as a cylindrical coil around a magnetic return path bracket, which connects the two stator poles to one another. Such a rotary actuator is highly cost-intensive in terms of production engineering, because of the great asymmetry of the actuating motor.
ADVANTAGES OF THE INVENTION
In contrast, the rotary actuator according to the invention, has the advantage of an actuating motor which is easy to manufacture in production-engineering terms, is of compact construction and whose magnetic latching torque is sufficiently large to rotate the throttle device back into its initial position, which releases a defined, minimum opening cross-section, when no current is flowing in the actuating motor. In this case, the rotor does not latch into the pole gaps, but rotates through 10.degree. to 20.degree. with respect to the pole gaps, because of the special air gap formation under the claw poles. In consequence, the rotation angle of the rotor is more than 50.degree. in the one rotation direction and less than 30.degree. in the other rotation direction. The rotary actuator according to the invention thus has a characteristic which is comparable to the so-called single-winding rotary actuators. The rotary actuator according to the invention is robust and has little susceptibility to defects.
Advantageous developments and improvements of the rotary actuator are possible by means of the measures outlined hereinafter.
If, according to a first embodiment of the invention, a reversible polarity DC current is applied to the stator winding, for example by connecting the stator winding to an output stage which can supply both polarities, by reversing the polarity, the throttle device can be transferred on the one hand into its closed position and on the other hand into its maximum open position. In this case, the closed position of the throttle device expediently lies in the actuating region of the rotor having the smaller rotation angle.
If, according to one preferred embodiment of the invention, a unidirectional DC current is applied to the stator winding, the polarity is defined such that, as the amperage increases, the rotor rotates in such a direction that the flow cross-section, which is released in each case by the throttle device, of the line through which flow passes initially falls to zero and then increases again to the maximum opening cross-section. The emergency mode of the rotary actuator, in which no current flows, is thus reached after the throttle device has passed through its closed position, which completely covers the opening cross-section.
Hard ferrite, plastic-bonded ferrite or plastic-bonded neodynian-iron-boron are used as magnetic materials for the permanent-magnet rotor. Rare earth magnetic materials are used in rotary actuators in the higher price range.
The permanent-magnet rotor may have a cylindrical permanent magnet with a diametric magnetisation direction, which permanent magnet holds the rotor shaft in a central, axial hole or is supported such that it can rotate on a knockout spindle. The permanent-magnet rotor can, however, also be implemented by means
REFERENCES:
patent: 4388913 (1983-06-01), Grimm et al.
patent: 4412517 (1983-11-01), Kobashi et al.
patent: 4426988 (1984-01-01), Greiner et al.
patent: 4428356 (1984-01-01), Kemmner
patent: 4494517 (1985-01-01), Kratt et al.
patent: 4647009 (1987-03-01), Idogzki et al.
patent: 5083744 (1992-01-01), Reinicke et al.
patent: 5087847 (1992-02-01), Giesbert et al.
Dick Dieter
Meiwes Johannes
Wendel Friedrich
Greigg Edwin E.
Greigg Ronald E.
Haszko D. R.
Robert & Bosch GmbH
Stephan Steven L.
LandOfFree
Rotary actuator for determining a flow cross section of a by-pas does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rotary actuator for determining a flow cross section of a by-pas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotary actuator for determining a flow cross section of a by-pas will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-581893