Electricity: magnetically operated switches – magnets – and electr – Magnets and electromagnets – With magneto-mechanical motive device
Patent
1992-01-31
1994-03-08
Donovan, Lincoln
Electricity: magnetically operated switches, magnets, and electr
Magnets and electromagnets
With magneto-mechanical motive device
335229, H01F 708
Patent
active
052931447
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to an electric rotary actuator. More particularly it relates to an electric rotary actuator, particularly for controlling a throttle cross-section in a line conducting operating fluid of an internal combustion engine which has a housing enclosing a motor actuator with windings and magnetic poles and a rotatable magnetic armature connected to a throttle member. Such rotary actuators are known, for example, from German Offenlegungsschrift 37 28 589 (=U.S. Ser. No. 203 800) and conventionally consist of an electric motor actuator, on the protruding, extended armature shaft of which a throttle member is mounted which is arranged in a fluid-conducting line. This rotary actuator thus requires a relatively large constructional space and additional seals between throttle member and motor actuator in order to prevent unwanted fluid leakages.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an electric rotary actuator which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in an electric rotary actuator of the above mentioned rotary type in which the housing has ducts leading into an interior space between the windings and each of which ends at another end face of the armature, and the armature has at least one cutout extending in an axial direction and bringable into alignment with the ducts, and the rotatable armature forms the throttle member through which the fluid to be controlled is conducted.
When the electric rotary actuator is designed in accordance with the present invention, it has the advantage that it is of much smaller and more compact construction, needs fewer individual parts and the prevention of fluid leakage is facilitated. This is achieved by the fact that the armature of the motor actuator itself forms the throttle member through which the fluid flows.
In accordance with another feature of the present invention, the wall of one of the ducts forms a control opening acting in conjunction with the throttle member. As a further measure for simplification, all stationary motor parts are injection moulded into a plastic housing. It is also advantageous to support the armature axially adjustably in order to be able to adjust the gap between throttle member and control opening which determines the leakage rate.
The windings can be injection molded in plastic and sealed with respect to the interior space through which the fluid flows. The stator accommodating the windings can be molded in without gap and provided with an impermeable coating towards the fluid space.
The armature can be permanently connected to a point-supported shaft. On the other hand, it can be connected to a shaft which is axially supported on the balls. The axial position of the shaft can be adjusted in order to adjust the play between the throttle member and the control opening. The shaft can be unilaterally subjected to the force of a spring which axially urges the throttle member in the direction of the control opening.
The cross-section of the ducts and of the cutouts can be approximately circle-segment-shaped.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a rotary actuator in longitudinal section according to line I--I in FIG. 2, and
FIG. 2 shows a cross section through the rotary actuator according to line II--II in FIG. 1.
DESCRIPTION OF A PREFERRED EMBODIMENT
A rotary actuator 1 has a 2-part housing consisting of a cup-shaped housing part 2 of plastic and a connecting part 3 which
REFERENCES:
patent: 3134404 (1954-05-01), Ziccardi
patent: 3206160 (1965-09-01), Bennett
patent: 3435394 (1969-03-01), Egger
patent: 4321571 (1982-05-01), Meyer
patent: 4491815 (1983-01-01), Idogaki et al.
patent: 4903578 (1990-02-01), Terp
Donovan Lincoln
Robert & Bosch GmbH
Striker Michael J.
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