Abstract:
The present invention relates to an actuating device with an electromotive rotary drive, via which an actuating element can be driven rotatably about an axis of rotation between a first end position and a second end position and can be acted upon out of the first end position by a spring. The electromotive actuating drive includes a reversing drive and the spring action upon the actuating element is effective between the first end position and an intermediate position. The spring action is ineffective between the intermediate position and the second end position. The intermediate position lies between the first end position and the second end position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    The present application claims priority to German patent application number 10243778.5 filed on 20 Sep. 2002, which is herein incorporated by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to an actuating device with an electromotive rotary drive and more particularly to the actuating element, which can be driven rotatably about an axis of rotation between a first end position and a second end position and further acted upon out of the first end position by a spring.  
           [0003]    In actuating devices of this type, it is known to operate the actuating element by means of the electromotive rotary drive counter to the force of the spring and over the entire actuating travel between the first and second end positions. During operation of the actuating device, a permanent operation of the electromotive actuating drive is also required. A permanent supply of current and therefore a permanent expenditure of energy is also consequently necessary. Since, in this case, the activating electronics of the actuating drive is also operated permanently, the load on these electronics, particularly as a result of heating, is high and necessitates higher-grade electrical and electronic components, with the result that the activation electronics are costly.  
           [0004]    If the actuating device serves for regulating the operation of a further device, such as, for example, for regulating the stream of a cooling liquid in a coolant circuit of the internal combustion engine for a motor vehicle, it is necessary that, in the event of a failure of the actuating device, a sufficient cooling liquid stream continues to be maintained, so that the internal combustion engine can be operated further, at least in an emergency running mode.  
           [0005]    This is not possible with known actuating devices, since, in the event of failure, the actuating element is moved into the second end position by the spring. This means that the cooling circuit is either completely shut off or completely open, the both of which do not correspond to the cooling requirements.  
         BRIEF SUMMARY OF THE INVENTION  
         [0006]    An object of the present invention is to provide an actuating device of the type initially mentioned above, which, in the event of a failure of its electromotive rotary drive, ensures that an intermediate position of the actuating element is assumed. The instant drive would operate with a saving of energy and further have a simple and cost-effective construction.  
           [0007]    These and other objects are achieved by the present electromotive actuating drive. The present actuating device comprises a reversing drive. Spring action upon the actuating element is effective between the first end position and an intermediate position and is ineffective between the intermediate position and the second end position. The intermediate position lies between a first and a second end position.  
           [0008]    Since the actuating element is adjusted and held counter to the force of the spring between the first end position and the middle position only, an increased expenditure of energy is necessary only in this actuating range. In the actuating range between the middle position and the second end position, the motive drive is necessary only in order to adjust the actuating element, without overcoming a spring force, but not in order to hold the actuating element in position. When the selected position is reached, the actuating drive is switched off, so that only low energy has to be expended for adjustment. No energy at all has to be expended for holding the element in an assumed position.  
           [0009]    Since the spring acts only in a partial range of the total range of adjustment between the first and second end position, it can be designed with lower force, as a result of which only a smaller amount of energy is required for the electromotive rotary drive.  
           [0010]    Thus, not only is the necessary energy requirement low, but also simpler and more cost-effective electrical and electronic components for activation and a motive rotary drive designed to be smaller may be used, since these parts are subjected to a lower thermal load.  
           [0011]    At the same time, however, it is ensured that, in the event of a failure of the electromotive rotary drive, the actuating element is set automatically into an emergency running position.  
           [0012]    In a simple and cost-effective design, the electromotive rotary drive may be a direct-current drive.  
           [0013]    The actuating element may be arranged on a rotatably mounted shaft that can be rotatably driven by the electromotive actuating drive.  
           [0014]    For the simple transmission of the rotary drive, the shaft has arranged on it, fixedly in terms of rotation, a gearwheel or toothed quadrant which can be rotatably driven by a drive pinion of the electromotive rotary drive directly or via one or more intermediate wheels.  
           [0015]    A simply construction is achieved in that the first end position is determined by a first limit stop and/or the second end position is determined by a second limit stop. Accordingly, by means of the stops, the rotational movement of the gearwheel or toothed quadrant or of the actuating element or of a component connected to the gearwheel, toothed quadrant or actuating element, can be limited.  
           [0016]    In this case, the ends of the toothed quadrant which are directed in the circumferential direction can be capable of butting up against the first and/or the second limit stop.  
           [0017]    Only a few simple components are necessary for spring action upon the actuating element, between the first end position and the intermediate position, when a stop element mounted freely rotatably about the axis of rotation is acted upon by the spring. The actuating element can be taken along in the direction of the first end position on the gearwheel or toothed quadrant counter to the force of the spring. The rotatability of the stop element in the opposite direction is limited by an intermediate stop determining the intermediate position.  
           [0018]    In this case, to achieve a further savings in terms of components, the stop element may have a driver which can be acted upon by the gearwheel or toothed quadrant in the direction of the first end position, and the stop element may have an intermediate-position stop which, in the intermediate position, is capable of butting up against the intermediate stop in the direction of the second end position.  
           [0019]    If the stop element is a stop disk which is mounted freely rotatably on the shaft of the actuating element, only a small amount of installation space is necessary for this simply constructed component.  
           [0020]    Likewise, only a small amount of installation space is necessary when the spring is a spiral spring having one end fixed and another end affixed to the stop element.  
           [0021]    In this case, the spiral spring may act with its one end, in particular with its radially outer end, upon a spring driver of the stop element.  
           [0022]    If the spiral spring surrounds the shaft, a compact construction is achieved.  
           [0023]    There is a particular savings in terms of construction space when an actuating-device housing possesses a bowl-like recess. Into this recess one end of the shaft projects approximately coaxially. The spiral spring, the stop element, and the gearwheel or toothed quadrant may be arranged in a sandwich-like manner in the bowl-like recess.  
           [0024]    In addition, the actuating-device housing may possess a motor chamber for receiving the electromotive rotary drive.  
           [0025]    No separate components are required when the first limit stop and/or the second limit stop and/or the intermediate stop are arranged on the actuating-device housing.  
           [0026]    The actuating element may be a rotary slide of a rotary-slide valve. The valve passage may be closed by means of a rotary slide. The slide may be driven rotatably, counter to the force of the spring, out of the closing position and into a partially open position. The slide may further be driven, free of a counterforce, out of the partially open position and into a fully open position. In this example, the partially open position may correspond to the intermediate position.  
           [0027]    In the present example, in the event of failure of the electromotive rotary drive, when the slide is in the partially open or intermediate position, a sufficient flow of medium through the rotary-slide valve is maintained in order to ensure emergency operation of a flow dependent unit.  
           [0028]    By means of the rotary slide, one or more further valve passages can be opened and/or can be shut off.  
           [0029]    A simple construction is obtained when the rotary slide is mounted rotatably in a rotary-slide chamber of the actuating-device housing, and one or more flow inlets and/or flow outlets issuing into the rotary-slide chamber and being capable of being overlapped with one or more flow passages of the rotary slide. In this case, the flow inlets and/or flow outlets may issue into the rotary-slide chamber approximately radially and/or-approximately axially.  
           [0030]    If the rotary-slide valve is a regulating valve in a coolant circuit of an internal combustion engine, then, in the event of a failure of the electromotive rotary drive, cooling of the internal combustion engine so as to ensure at least emergency operation is maintained. The maintenance is effectively simply. The coolant circuit, as is known in the art, may carry a cooling medium such as engine coolant liquid.  
           [0031]    The present invention further comprises An actuating device, comprising: an electromotive rotary drive for driving an actuating element about an axis of rotation between a first and a second end position, a spring for acting upon said actuating element in said first end position, wherein said electromotive actuating drive is a reversing drive and said spring action upon said actuating element is effective between said first end position and an intermediate position and is further ineffective between said intermediate position and said second end position, the intermediate position lying between said first and second end position. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0032]    The novel features believed characteristic of the invention are set out in the claims below. The invention itself, however, as well as other features and advantages thereof, are best understood by reference to the detailed description, which follows, when read in conjunction with the accompanying drawing, wherein;  
         [0033]    [0033]FIG. 1 depicts a perspective view of an actuating device of a rotary-slide valve;  
         [0034]    [0034]FIG. 2 depicts a perspective exploded illustration of the actuating device according to FIG. 1; and  
         [0035]    [0035]FIG. 3 depicts an illustration of the rotary-slide positions over the regulating range of the actuating device according to FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0036]    The present invention will be described with respect to a rotary slide valve as being a regulating valve for an internal combustion engine coolant system. The present actuating device drives the rotary slide. For clarity purposes, details about the coolant system and internal combustion engine are not depicted. It is within the scope of the present invention that it find application beyond that discussed below.  
         [0037]    As depicted in FIG. 3, the present regulating valve comprises a rotary slide  3  rotatably mounted in a rotary-slide chamber  1  of an actuating-device housing  2 . The regulating valve includes two radial flow passages  4  and  5 . The rotary chamber includes a short-circuit outlet  6  and a cooling outlet  7 . The flow passages  4  and  5  are positioned on the rotary slide such that the slide  3 , in a first position  40 , shuts or seals off the rotary chamber to both outlets  6  and  7 , and in a second position  50 , the short-circuit outlet remains open, while the cooling outlet remains closed. In a still third position  60 , it is the short-circuit outlet which remains closed while the cooling outlet is open.  
         [0038]    As depicted in FIGS. 1 and 2, the rotary slide chamber  1  comprises a bowl-like design. The chamber is axially connected with a flow inlet (not shown) via which coolant is supplied into the chamber. A corresponding orifice in the bottom of the chamber is included. A shaft  8  projects through the orifice. The shaft is fixedly connected to the rotary slide  3 . The shaft is also coaxially connected to the slide. A first end of the shaft projects through the chamber bottom and a second end projects into recess  9 . The recess  9  is also bowl-like. Actuating device housing  2  comprises recess  9 .  
         [0039]    The shaft  8  second end projecting from the recess is first surrounded by a spiral spring  10 . The radially inner end of the spring  10  is arranged fixedly in the region of the bottom  11  of the recess  9 . The radially outer end of spring  10  comprises a hook  12 . A stop disk  14  is included. The stop disk  14  includes a spring driver  13  which is engaged by hook  12 . The stop disk is freely and rotatably mounted on shaft  8 , parallel to spiral spring  10 .  
         [0040]    A toothed quadrant  15  is fixedly connected to shaft  8  such that rotational movement from the shaft is imparted on the quadrant. The quadrant is also sandwiched with and arranged atop of stop disk  14 . The stop disk  14  includes an axially directed driver  16 . The driver projects into the path of movement of the toothed quadrant  15  and via which the stop disk  14 , rotating until the toothed quadrant  15  comes to bear with one end  22  against a first limit stop  17 , comes into bearing contact and the spiral spring  10  being tensioned. The first limit stop  17  is arranged fixedly on the actuating-device housing  2 .  
         [0041]    The toothed quadrant  15  can be rotated in the opposite direction of rotation until it comes to bear against a second limit stop  18 . The stop disk  14  includes an intermediate-position stop  19  along its circumference. The stop disk  14 , along with toothed quadrant  15  freely rotate about shaft  8 , until stop  19  comes into contact with an intermediate stop  20 . In FIG. 2, intermediate stop  20  is shown with second stop  18 . The intermediate stop may be positioned elsewhere between first and second stops  17  and  18 . When stop  19  comes into contact with stop  20 , the stop disk  14  and toothed quadrant  15  are prevented from rotating further in the direction of travel.  
         [0042]    However, since the intermediate-position stop  19  leads toothed quadrant end  21  in the direction facing second limit stop  18 , the toothed quadrant  15  can still rotate further without the stop disk  14 , before this rotational movement is limited by abutment against the second limit stop  18 .  
         [0043]    An intermediate pinion  23  engages toothed quadrant  15 . The pinion is connected, fixed and coaxially, to intermediate wheel  24 . Wheel  24 , in turn is connected with drive pinion  25  of a reversibly drivable direct-current (DC) motor  26 . The DC motor  26  is arranged in a motor chamber of the actuating-device housing  2 . The aforementioned connections generally refer to toothed connections between the mentioned components. Other such connections envisioned by one skilled in the art would be applicable.  
         [0044]    When the direct-current motor  26  is not operable or dead, the toothed quadrant  15  is moved by the spiral spring  10 , via the stop disk  14 , out of a position nearer to the first limit stop  17  and as far as into the intermediate position in which the intermediate-position stop  19  comes to bear against the intermediate stop  20 . In this intermediate position, the rotary slide  3 , co rotated via the shaft  8 , is then in a partial opening position, in which the cooling outlet  7  is partially opened, so that cooling liquid can flow to the internal combustion engine and cool the latter.  
         [0045]    If the cooling connection  7  is to be opened further and, if appropriate, completely, current is supplied to the direct-current motor  26  until the rotary slide  3  has reached the desired opening position. With the supply of current being terminated, the rotary slide  3  remains in this position. Due to the drive reversibility, the rotary slide  3  can be moved in both directions of rotation.  
         [0046]    If the cooling outlet  7  is to be opened to a lesser extent than the partial opening position, current is supplied to the direct-current motor  26  in such a way that the toothed quadrant  15  moves with its end  22  in the direction of the first limit stop  17 . Since, in this case, the stop disk  14  is taken along by the toothed quadrant  15  via the driver  16 , the spiral spring  10  is also tensioned, so that its force also has to be overcome (see for example FIG. 1). This movement leads first to a further closing of the cooling outlet  7  up to the complete shut-off of the latter and to an opening of the short-circuit outlet ( 50 ). When the toothed quadrant  15  is rotated further toward the first limit stop  17 , a shut-off of the short-circuit outlet  6  also takes place ( 40 ).  
         [0047]    [0047]FIG. 3 depicts the various intermediate positions of the regulating valve over the entire range of adjustment  27  of the rotary slide  3 . In this case, the illustration on the left ( 40 ) shows the fully closed position of both outlets  6  and  7 , in which the direct-current motor  26 , overcoming the force of the spiral spring  10 , has moved the toothed quadrant  15  until it comes to bear against the first limit stop  17 .  
         [0048]    When the toothed quadrant  15  is driven out of this position and in the direction of the second limit stop  18 , a rotation of the rotary slide  3  takes place. The slide rotation is effected with the cooperation of the spiral spring  10  over a range  28 , short circuit operating range, and into the intermediate position. In the intermediate position, in which the short-circuit outlet  6  is then closed and the coolant outlet  7  is partially opened, the effective range of the spiral spring  28  ends.  
         [0049]    From then on, an adjustment of the rotary slide  3  into its fully open position, in which the toothed quadrant  15  comes to bear against the second limit stop  18 , may occur without a spring force having to be overcome.  
         [0050]    The invention being thus described, it will be obvious that the same may be varied in many ways. The variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.