Actuating device

The invention relates to an actuating device, particularly an actuating magnet, for actuating valves. In order to improve the sealing action of an actuating magnet, the invention provides that a contacting plug insert (48) has a seating surface (54) against which an annular sealing part (52) rests and which extends in the form of a groove inside the plug insert (48). The groove depth is selected so that, when in an unpressed state, approximately half of the sealing part (52) is accommodated inside the groove (56). When the groove (56) is fitted with the sealing part (52), it is completely filled whereby resulting in a projection that sealingly closes the gap (58) arising between a plug plate (40) and an outer peripheral surface (50) of the housing (18).

The invention relates to an actuating device, in particular an actuating magnet, for actuating valves, having a housing and a coil element located therein, a coil element in which a switching component is guided, and which is provided with the winding of a conductor which is connected by a retaining device to contact components of a plug plate which is seated on the outer peripheral surface of the housing while maintaining a distance by means of a plug insert, the plug insert for seating an annular sealing component having a seating surface which extends in the form of a groove within the plug insert, and in the installed state, by pressing the sealing component, at least the gap, which is formed in the direction of the coil element between the plug plate and the outer peripheral surface of the housing, being closed to effect sealing.

These actuating devices which are also termed actuating magnets are known and are freely available commercially in a host of versions. The switching component is formed essentially from a tubular pin which, when the coil is electrically excited via a connector plug which can be connected to a plug plate, traverses a definable path and in this connection actuates an actuating or switching process, and, for example, in a valve enables blocking and routing of fluid flows. If these known actuating devices are used in regions with high humidity, as occurs among others things also with condensate formation, the moisture penetrates into the housing interior, especially to the coil element with the winding, and with the onset of corrosion leads to the device becoming unusable. To avoid this problem, it has already been suggested in the prior art that the housing of the actuating device be completely surrounded with a plastic potting mass which keeps moisture away; but this can lead to actuating devices of very large size which are not suited for use in automotive engineering, where fundamentally only little installation space is available. Moreover potting the switch housing with the plug plate can lead to an unattractive appearance of the actuating device.

To alleviate these disadvantages, in a generic actuating device as claimed in DE 43 41 087 A1 it has already been suggested that the plug insert for seating of an annular sealing component be provided with a seating surface which protrudes with a definable axial projection over the bottom of the plug plate facing the outer peripheral surface of the housing, such that in the installed state at least the gap which is formed in the direction of the coil element between the plug plate and the outer peripheral surface of the housing is closed to effect sealing by pressing the sealing component. In this way moisture can no longer travel into the housing interior at the site of the upper part of the plug plate and in particular cannot reach the coil element with the winding. In the known solution the plug insert has an inside thread and two insulation piercing inserts which are each provided with lengthwise teeth and which are separated from one another by a groove-shaped contact shoulder for holding the annular sealing component. In this way, with simple manufacture the plug insert can be securely joined both to the plug plate and also then together with the plug plate to the housing of the actuating device. Since in the known solution gap formation in the area of the plug plate between the potting mass and the outer peripheral surface of the housing is extremely narrow and in this respect is then closed by the annular sealing component in the pressed state, the sealing component in the direction of the gap is very greatly extended and compressed; this can lead to high material loading in the annular sealing component and especially due to the sharp-edge configuration of the insulation piercing inserts, damage to the sealing component is possible. This can adversely affect the sealing function such that in later operation failures of the actuating device occur, and consequently failures in the hydraulic circuits to which the actuating device is functionally connected.

On the basis of this prior art, the object of the invention is to devise an actuating device which is as small as possible and which is suited especially for use in automotive engineering and is still reliable in operation even at high humidity, even over a longer interval of use. This object is achieved by an actuating device with the features of claim1in its entirety.

In that, as specified in the characterizing part of claim1, the groove depth is chosen such that in the unpressed state approximately half of the sealing component is held in the groove and that in the installation state the groove with the sealing component is completely filled except for a projection such that the gap which is formed is closed to effect sealing, the humidity at the site of the upper part of the plug plate can no longer travel into the housing interior and especially not to the coil element with the winding. In that the annular sealing component is enclosed in the groove of the plug insert, which moreover has a large volume of displacement space into which the sealing component can be displaced when injected in place with the plastic potting mass, harmful compression, shearing and transverse forces on the sealing component are also for the most part precluded; this ensures that even beyond longer periods of use the sealing function is reliably maintained. The enclosed sealing component especially to the outside preserves its partially annular sealing surface and in this way can effect sealing of the indicated gap with a high degree of elasticity. Since the groove in the plug insert can be provided on the groove bottom with rounded transitions to the transversely running side walls, sharp edge geometries which can adversely affect the sealing action within the plug insert are avoided. Without being pressed or displaced as shown in the prior art into a sealing gap which runs parallel to the lengthwise axis of the plug insert, the preferably O-ring-shaped cross section of the sealing component is preserved which for this purpose can best perform its sealing function for the gap.

Other advantageous embodiments of the actuating device as claimed in the invention are the subject matter of the other dependent claims.

The switching device has a coil element10of plastic material, the coil element10on the end side having two annular flanges12between which the winding stack14of a conductor16extends, this coil having been omitted inFIG. 1for the sake of simplification. A switching component (not shown) is guided in the coil element10, and with this switching component especially hydraulic valves can be actuated and actuated. The coil element10is surrounded by an essentially cylindrically made housing18of metallic material. This structure is conventional in actuating magnets so that it will no longer be detailed here.

The annular flange12of the coil element10which faces the vicinity forms an annular plate20(FIG. 2) which, with a retaining device22molded Unto it, extends through a front, groove-shaped recess24in the housing18, both the annular plate20and also the retaining device22at least partially along their outer contour exposing a radial gap26to the housing parts18facing them; the gap can be injected with a plastic potting mass28. For the sake of simplicity, the potting mass28is likewise omitted inFIG. 1. To center the annular plate20within the inner periphery of the housing18, it can be held by way of radial projections30protruding along its outer periphery at a distance and centered in the middle for injecting or casting in place with the potting mass28. The radial projections30are dimensioned such that they center the retaining device22relatively accurately for insertion into the casting or injection mold. After insertion into the mold however a gap forms between the housing18and the retaining device22. The retaining device22has a middle piece32which is made as a plate which runs flat and which projects radially over the groove-shaped recess24.

The retaining device22on the end side on the plate-shaped center piece32has two pin-like prolongations34around which the ends of the conductor16are wound, in order in this way to ensure a fixed link of the conductor16to the retaining device22. For further guidance of the conductor16, on the top of the middle piece32in each respective outer region, there are two pairs of crosspieces36which each have a receiver with a V-shaped cross section into which the conductor16can be inserted. Located in the center on the middle piece32and between two crosspieces36of the retaining device22which are located directly adjacently opposite, there is a guide means (not detailed), by means of which the conductor16crossing in the indicated region and without touching at this point is routed to run toward the winding stack14.

The conductor16is routed by the retaining device22over a definable path between the respective pairs of crosspieces36such that it is freely accessible to direct contact with two contact components38of one plug plate40from at least one side, but preferably from all sides. The respective contact component38of the plug plate40has a roof-like connecting piece42which can be seated from the top on the conductor piece between the two crosspiece pairs36. The two free leg pieces of each connecting piece42which encompass the conductor16within the retaining device22can be can be pressed together and then welded to one another, a conductive connection arising between the respective contact component38and the assigned piece of the conductor16. The roof-like connecting pieces42are each arranged offset to the outside toward the respective prolongation34and are connected to one respective flat contact path44each, on which arranged perpendicular to it and connected to it there is the lug46of the plug of the plug plate40which projects over the top of the switching device. This contact path40is shown inFIG. 1only for the ground connection which is likewise made as the lug46of a plug, which in the same manner as the other lugs46projects to the top and is designed for connection to female plug parts of a connector plug (not shown) for later power supply.

All contact paths44and lugs46of plugs can be punched or cut out of a flat plate and are then potted with the plastic material of the plug plate40. The plug plate40essentially in the middle has a plug insert48which is designed as a cylindrical sleeve. By means of this plug insert48the plug plate40can be seated on the outer peripheral surface50as the outside wall of the housing18while maintaining a distance.

The plug insert48for seating of the annular sealing component52(FIG. 1) has a seating surface54which extends in the form of a groove within the plug insert48. The depth of the groove56is chosen such that in the unpressed state as shown inFIG. 1only approximately half of the sealing component52is accommodated. In the installed state which is not shown, by pressing the sealing component52, as will be detailed below, the gap58which is formed in the direction of the coil element10between the plug plate40and the outer peripheral surface50of the housing18is closed to effect sealing. The cross section of the groove56is rectangular, especially square, in the unpressed state the sealing component52at least along two diametrically opposite sealing lines60adjoining the inside of the groove56. The two side walls62and64of the groove56are vertical on the groove bottom66, in the unpressed state as shown inFIG. 1, between the sealing component52held in the groove56and the groove56itself, a displacement space68is formed. The displacement space68itself is divided in turn into two component spaces68a,bin turn via the annular sealing component52. In order to protect the sealing component52consisting of an elastic material, especially rubber material, against damage in the groove base, the groove56in the area of the transition between its respective side walls62,64and the groove bottom66has transitions which are arc-shaped viewed in cross section. If the annular sealing component52in the unpressed state as shown inFIG. 1adjoins the groove bottom66with its inner periphery, in this respect another sealing line is implemented with the walls of the groove56.

The plug insert48is divided by the groove56made on the outer peripheral side into two regions70,72, of which one region70is held in the housing18such that the groove56with its one lower side wall64offset by a step74ends with the outer peripheral surface50of the housing18. In this respect, the step74also limits the gap58which is to be sealed later. The other region72of the plug insert48tapers as an indentation in the direction of the plug plate40, and on the side facing the groove56in the indentation76formed in this way, there is a seating surface78for the contact component38of the plug plate40which is used as the ground connection. In particular, the plug insert48is formed from an electrically conductive, especially metallic material and the plug insert48extends through the indicated ground connection in the form of the contact component38. The height of the plug insert48is chosen such that it extends between the inside wall80of the housing18to the top82of the plug plate40.

Between the outer peripheral surface50of the housing18and the plug plate40a supply space84is delineated which is used to supply the potting mass28for sealing purposes, when the parts shown inFIG. 1are injected in place the sealing component52being pressed into the displacement space68of the groove56until the elastic parts of the sealing component52are in contact with the side walls62,64and with the bottom66of the groove56. In order to facilitate the delivery of the potting mass28, there are delivery passages86in the housing18. When the sealing component52is pressed into the groove56, a certain projection remains to the outside which retains essentially its arc shape and in this way seals the indicated gap58, especially at the site of the indentation-like transition to the housing wall in the form of the step74. In addition to the described displacement motion and the pressing of the sealing component52in the groove66, due to the potting mass28no other forces are applied, especially no transverse or shearing forces which could damage the sealing component52or shift it into the groove-shaped sealing seat; this could adversely affect the sealing action.

The plug insert48is made as a smooth sleeve part on the outer peripheral side; but it would also be conceivable to provide ribbing or the like in order to facilitate the connection to the plastic potting mass28. It is surprising to one with average skill in the art in the field of actuating and switching magnets that by using a conventional O-ring in a correspondingly shaped plug insert48relative to the known solutions a much improved sealing action is obtained for a long operating interval without the sealing component52preferably in the form of an O-ring being exposed to excessively damaging stresses. The component spaces68a,bof the displacement space68which form the free spaces also form a receiving possibility for the O-ring, since temperature fluctuations, especially in the form of a temperature increase, can change the geometrical dimensions of the O-ring, especially in the form of a volumetric expansion which is accommodated by the component spaces68a,b.