Patent Publication Number: US-6338330-B1

Title: Device for moving a valve flap

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a device for shifting the position of a valve flap. 
     Such a device is known from U.S. Pat. No. 4,056,082. For space reasons it may be necessary to provide the vacuum box that is used with a coupling rod which makes possible an eccentric output of the adjusting force which is effected by the vacuum box. In accordance with the aforementioned publication, this is achieved in that the vacuum box is attached to an adjusting mechanism by means of which the output force can be displaced to another location. This, however, gives rise to additional manufacturing expense, which makes the apparatus more costly. In addition, the susceptibility of the apparatus to operational disturbances, e.g. by fouling of the linkage mechanism, is increased. In addition, additional space is required by the adjusting mechanism, and the apparatus is made heavier. 
     SUMMARY OF THE INVENTION 
     It is therefore the object of the invention to provide a device for shifting the position of a valve flap which will operate reliably, is simply constructed, has a low weight, requires little space, and at the same time makes possible an eccentric output of force. This object is achieved by the features of claim  1 . 
     The substantial advantage of the invention is that the diaphragm device can be arranged at virtually any place in the vicinity of the valve flap, and the force is applied through the corresponding linkage. In particular, it is possible to arrange the diaphragm device such that it does not negatively affect the design of the overall air intake system but instead adapts itself to the form of the system. 
     In one practical embodiment of the invention the functions of the transmission of force and the mounting of the diaphragm are integrated in a single component. As a result, the cost of the manufacture of this diaphragm device is but slightly greater in comparison with conventional designs with a centralized application of force, which assures the cost of the proposed solution will be reasonable. 
     Another embodiment of the invention envisions constructing the transmission ratio of the operating rod to be variable, so that the range of movement of the diaphragm device can easily be adapted to the required flap movement. 
     It is advantageous to select the shape of the diaphragm such that the actuating force resulting from the pressure on the diaphragm corresponds as nearly as possible to the line of action of the traverse rod or to the point of linkage to the coupling rod. This construction has the advantage that the stress on the joint arranged on the hook plate in the housing of the diaphragm device is minimized and the pressure force of the diaphragm device is almost entirely available as an actuating force. 
     According to one embodiment of the invention, the diaphragm device is a vacuum box which can also have a diaphragm contour which differs from the conventional round shape. Such vacuum boxes are generally used in motor design; they are very reliable and inexpensive to manufacture. 
     To connect the coupling rod, traverse rod and valve flap and for the one-sided journaling to the hook plate of the asymmetrical vacuum box, ball joints are preferred. These are hooked or snapped to each other. In this way the assembly costs can be considerably reduced. 
     It is possible to additionally arrange a length compensating member in the traverse rod or the coupling rod and also to provide the diaphragm device or vacuum box with a return spring. These elements also result in an optimal adaptation to the system. 
     These and additional features of preferred embodiments of the invention will be found not only in the claims but also in the description and the drawings, the individual features being applicable individually or jointly in the form of subcombinations in embodiments of the invention and in other fields and may constitute advantageous as well as independently patentable embodiments, for which protection is hereby claimed. 
     The invention will be further explained hereinafter with reference to working embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a sectional representation of a device for shifting the position of a valve flap, 
     FIG. 2 shows a sectional view according to FIG. 1 with the valve flap open, 
     FIG. 3 shows a sectional representation of a device for shifting the position of a valve flap in an embodiment with an asymmetrical vacuum box, and 
     FIG. 4 shows the contour of the asymmetrical diaphragm in the view A in FIG. 2 with the housing cover removed. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The sectional representation according to FIG. 1 shows a passage  10  carrying aspirated air, which is closed by a pivotable flap  11 . The pivotable flap  11  is journaled at both ends in a housing  12  and has a lever  13  at the upper journal location. This lever  13  is connected via a ball joint  14  to a traverse rod  15 . The traverse rod is in contact on the end opposite the ball joint  14  with a coupling rod  16 . The coupling rod  16  is mounted for rotation in a bearing socket  17 . An actuator housing  18 , which is connected by the flange  19  to the housing  12 , carries a vacuum box  20 . This vacuum box has a housing cover  21  with a connection  22  for a vacuum hose, not shown here. In the housing cover  21  there is a resiliently mounted diaphragm  23  which is supported against a pressure spring  24 . The diaphragm is equipped with a joint hook  25  which encloses a mounting pin  26  on the coupling rod  16 . In the position of the pivotable flap  11  shown here, the diaphragm  23  is in the rest position, and no vacuum is applied. 
     FIG. 2 shows the device for shifting the position of a valve flap in the open position. The pivotable flap  11  is rotated by 90° as a result of a vacuum applied to the connection  22 . The vacuum produces an axial movement of the diaphragm  23  against the force of the spring  24 ; this movement is transmitted through the coupling rod  16  and the traverse rod  15  to the pivotable flap  11 . 
     Of course, intermediate positions are also possible. The position of the pivotable flap  11  is dependent on the applied vacuum. Usually, however, the valve flap is operated only between the two positions, closed and open. 
     FIG. 3 shows the operation of an asymmetrical vacuum box which is connected to the position adjusting mechanism of the throttle valves. The heart of the asymmetrical vacuum box  20  is the hook plate  30  which is connected to the diaphragm  31  and at the same time carries a pivot point  29 . It thus combines the functions of a diaphragm disk  27  and coupling rod  16  (FIG.  1 ). The hook plate is journaled on at least one ball joint  28  in the housing of the vacuum box. The pivot point  29  of hook plate  30 , connected to the traverse rod  15 , therefore performs a circular movement when the vacuum box is actuated. The throttle valve  11  is thus shifted in position in the same manner as in the embodiment described in FIG.  1 . As an alternative to the jointed pivot point  29 , a rigid connection can also be provided between the traverse rod and hook plate. In this version the ball joint  28  is omitted, and the hook plate  30  executes a substantially translational movement. The vacuum box is operated by a vacuum which can be applied to a vacuum connection  22  and which acts against a spring  24 . 
     FIG. 3 shows a plan view of the vacuum box with the housing cover  21  removed, viewed from the direction A (see FIG.  2 ). The hook plate is shown in broken lines. The external contour  34  and the spring socket  33  can be seen. The housing wall  35  of the vacuum box receives the sealing bead  36  of the diaphragm  31 .