Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-07-16
2004-03-30
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S07500D
Reexamination Certificate
active
06713910
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a control unit comprising at least one electric motor with a rotary magnet constructed as a rotor. The invention also relates to a control unit for a motor vehicle which includes a control element, especially a flap valve.
Electric motors with rotary magnets are known, for example, from DE 40 26 918. The object of using such an electric motor is to make it possible to create a direct drive of a control element within a limited angular range without the aid of commutators. The electric motor drive according to this document is suitable, in particular, for adjusting a member, which controls the fuel-air mixture of an internal combustion engine.
In automotive engineering, rotary magnets are used to control flaps because they provide a substantially shorter switching times in the range of about 25 milliseconds. With conventional dc motors, the obtainable switching times are about 100 milliseconds. Compared to conventional electric motors, however, the current consumption of motors equipped with a rotary magnet is 6- to 7-fold. As a result, currents of 5 amperes are required. Since an electric motor with rotary magnet has no self-locking element, the control element to be actuated must be held by a spring against a limit stop and is brought into the other position by switching on the motor. To keep it in this other position, the motor must remain on, so that a continuous driving power of 60 watts is required. This has the drawback of increasing the fuel consumption of the vehicle.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a drive for a control member with low average energy consumption over the operating time of the control element.
A further object of the invention is to provide a drive for a control member which can assure short switching times.
These and other objects are achieved in accordance with the present invention by providing a control unit comprising an electric motor with a rotary magnet constructed as a rotor, having a drive shaft and an externally excited stator, wherein the motor is provided with at least one releasable arresting element interposed between movable and stationary parts of the motor, and the arresting element when engaged holds the drive shaft in a set position.
In accordance with a further aspect of the invention, the objects are achieved by providing a control module comprising a control element and an actuator, the actuator comprising an electric motor with a rotary magnet constructed as a rotor and having a drive shaft connected to the control element and an externally excited stator, wherein the control module further comprises at least one releasable arresting element interposed between movable and stationary parts of the module, and the arresting element when engaged holds the drive shaft in a set position.
The control unit according to the invention has an electric motor known per se with rotary magnets as a rotor and with a separately excited stator. The control unit is characterized in that the motor has at least one arresting element between movable and stationary parts for keeping the drive shaft in a certain position. This position is determined by the application and is determined, for instance, by the design constraints of the control member that is to be driven. The release force for the arresting element must be smaller than the actuating force applied by the motor, so that the control element can be moved from the engaged position into another position by actuating the motor. If, however, the control element is in the desired position and secured, it is not necessary to apply a current to the motor, since the control element is fixed in this position. Only for the switching process itself is a current required to adjust the control element.
It is advantageous to provide two arresting elements for the control element, one in each end position. Actuating the motor then switches the control element from one secured position to the other. A corresponding control of the motor with different currents makes it possible to provide additional locks for intermediate positions of the control element. They fix the control element when a low rapid current is applied and can be overcome when the full rapid current is applied. The above-described known control unit in which a counter force is produced by a spring can also be improved by an arresting element. The release force for this lock must be greater than the spring force acting on the control element in the corresponding end position. With the support of the motor, the control element can be released from its secured end position.
In accordance with an alternative embodiment of the invention, both the control element and the electric motor are integrated into the control unit. The arresting element can accordingly be fixed either to the control element or to the motor. It is only necessary that the arresting element is provided with effective cooperating elements between movable and stationary parts of the control element. For instance, the control element can be configured as a flap valve, and its end positions can snap into the arresting elements, which are fixed directly to the motor housing. This provides greater design freedom for the corresponding application. Furthermore, conventional rotary magnet motors may be used, and locking can be assured by movable and stationary parts of the control element.
According to one specific embodiment of the invention, at least one arresting element has a limit stop for the control element. This precisely defines the end position of the control element. Advantageously, the limit stop can furthermore have a sealing surface if the control element is configured as a sealing member. The sealing surface interacts directly with the sealing member to improve its functional reliability.
In accordance with another embodiment of the invention, locking can be ensured by elastic elements, which produce a form-fit connection. To release and close the lock, the elastic element is deformed. Another possibility is to create the lock by mating or corresponding contact surfaces, which produce a frictional connection. This can also provide a seal between the control element and the arresting element, which has the same effect as the above-described sealing surface.
These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or in the drawings, and the individual features each may be implemented in embodiments of the invention either individually or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed.
REFERENCES:
patent: 4059779 (1977-11-01), Wistinghausen
patent: 5600191 (1997-02-01), Yang
patent: 5796192 (1998-08-01), Riepl
patent: 5920136 (1999-07-01), Schmid
patent: 4026918 (1992-02-01), None
Crowell & Moring LLP
Filterwerk Mann & Hummel GmbH
Nguyen Tran
LandOfFree
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