Closure cp for a motor vehicle radiator

Abstract

A closure cap (10) for a fixed neck of a motor vehicle radiator is provided with a cap outer part (12), which comprises a closure element (17) that can be joined to the reservoir neck, and comprises a grip element (13) that is held in a manner that permits it to he twisted in relation to the closure element. A torsional stop (20) is provided between said closure element and grip element. The aim of the invention is to provide a closure cap of the aforementioned type with safety-relevant functions of the torsional stop and of the reduction of excess pressure in a structurally simple manner whereby permitting them to be exactly adapted to one another. To this end, an actuator (15) that can be expanded when subjected to heat is provided both for axially engaging and disengaging the coupling insert (46) of the torsional stop (20) as well as for adjusting the pretension with which the valve body (22) of the valve arrangement (11) is pressed against the sealing seat (21).

Description

[0001] The present invention relates to a closure cap for a fixed neck of a container, in particular a motor vehicle radiator, as generically defined by the preamble to claim 1.

[0002] In one such device, from German Patent Disclosure DE 197 53 597 A1, the torsional stop between the closure element and the grip element is formed by an axial coupling bolt, which is acted upon by a spring assembly functioning as a function of temperature, while the prestressing of the reciprocating valve body of the valve assembly is adjustable under pressure control mechanically or by electric motor. A disadvantage of this is that in such closure caps, the safety-relevant functions are performed by two differently designed and also differently triggered components. Not only does this mean complicated engineering provisions, but it also has the problem that the safety-relevant functions that respond to different reference variables can be adapted only very poorly to one another.

[0003] The object of the present invention is therefore to create a closure cap of the type defined at the outset, with which the safety-relevant functions of the torsional stop and of the overpressure reduction can be performed in a structurally simpler way and in particular can also be more precisely adapted to one another.

[0004] For attaining this object, in a closure cap of the type defined at the outset, the characteristic recited in claim 1 is provided.

[0005] By the provisions of the invention, it is attained that a single component is provided for both securing against relative torsion and for varying the overpressure reduction, leading to a structural simplification of the closure cap, and because of the single reference variable used for performing the safety-relevant functions, these functions are always adapted to one another.

[0006] Advantageous features of the actuator are disclosed by the characteristics of claim 2 or 3.

[0007] A structurally simple embodiment is obtained by the characteristics of claim 4, which moreover has the advantage that the reference variable, such as the temperature or pressure in the container, can be picked up in a suitable way independently of the actuator. An advantageous heat transfer from the heating resistor to the actuator is obtained by the characteristics of claim 5.

[0008] Further advantageous features in terms of the disposition of the actuator and of an electronic triggering unit between the base value and the actuator become apparent from the characteristics of claim 6, or one or more of claims 7-10. The characteristics of claim 11 and claim 12 show an embodiment of the connection between the valve body and the actuator, on the one hand, and between the torsional stop and the actuator, on the other.

[0009] Further details of the invention can be learned from the ensuing description, in which the invention is described and explained in further detail in terms of the exemplary embodiments shown in the drawing.

[0010] Shown are:

[0011] FIG. 1, in a schematic longitudinal section, a closure cap for motor vehicle radiators in a preferred exemplary embodiment of the present invention, in a first position, which is the position of repose or outset position;

[0012] FIG. 2, in the left half of the section, a view corresponding to FIG. 1, and in the right half of the section in a second active position;

[0013] FIG. 3, in the left half of the section, a view corresponding to FIG. 1, and in the right half of the section in a third active position.

[0014] The closure cap 10 shown in the drawing in a preferred exemplary embodiment has a overpressure valve assembly 11 inside a cylindrically embodied inner part 14 and a torsional stop 20 between an outer part 12 and a handle or grip element 13 that serves, via a male-threaded part 17, to screw the closure cap 10 onto the opening of a neck, not shown, of a motor vehicle radiator or other container and to unscrew it again; both the overpressure valve assembly 11 and the torsional stop 20 are triggered in such a way that on the one hand, the opening pressure of the overpressure valve assembly 11 and on the other the unlocking and locking motion of the torsional stop 20 can be adjusted and assured by means of a single electrothermal actuator 15. The overpressure valve assembly 11 can be adjusted to an opening pressure that takes the motor vehicle radiator overpressure in normal operation into account and to an opening pressure that corresponds to the higher motor vehicle radiator overpressure that results from the dammed-up heat that develops when the motor vehicle engine is switched off. The adjustment of the torsional stop 20 at normal pressure of the motor vehicle radiator, that is, once the coolant has cooled down, causes the torsional stop 20 to effect a torsion lock between the grip element 13 and the outer part 12, so that the closure cap 10 can be screwed on and unscrewed, while at motor vehicle radiator overpressure with the coolant thus hot, the torsional stop undoes the torsion lock between the outer part 12 and the grip element 13, so that to prevent the closure cap 10 from being unscrewed, the grip element 13 rotates idly relative to the outer part 12.

[0015] In the drawing, the inner part 14 can be inserted sealingly via an O-ring 16, in a manner not shown, into the neck of the motor vehicle radiator or other container. It is understand that instead of being provided with a male-threaded 17, the outer part 12 can also be provided with a bayonet mount.

[0016] The cylindrically embodied inner part 14 of the closure cap 10 that is equipped with the overpressure valve assembly 11 has a bottom 18 and, above the bottom, an inward-protruding annular edge 19, whose upper region is provided with a sealing seat 21 for a valve body 22 of the overpressure valve assembly 11. The valve body 22 is a part that is hat-shaped in the middle, and a sealing disk 26 rests on its circumferential flange 24; the flange and disk are acted upon by a compression spring 28 or overpressure valve spring; on its other end, this spring is braced on a pressure sleeve 29 that is guided such that it can be moved axially up and down in a guide part 31, having an axial stop 34 for the pressure sleeve 29, and rests on an adjusting ring 30 resting on the actuator 15. Between the bottom 18 and the inner part 14, openings 32 pointing into the motor vehicle radiator or container are provided. The inner part 14, on its outer circumference and opposite the smaller-diameter guide part 31, also has an opening 33, which communicates with the outside atmosphere. When the valve body 22 has lifted from the sealing seat 21, a fluidic connection between the radiator or container interior and the ambient air results.

[0017] Inside the overpressure valve body 22, a negative-pressure valve body 36 is also provided, whose lower annular edge 37, because of a compression spring 38, is braced on the sealing seat 21 of the overpressure valve body 22 inside the annular edge 19 of the bottom. A tappet 39 of the overpressure valve body 36 passes through the hat-shaped overpressure valve body 22 and protrudes past it; the compression spring 38 is disposed between the tappet 39 and the top side of the hat-shaped overpressure valve body 22.

[0018] The inner part 14 is suspended, relatively rotatably, by an upper collar 41 in a lower extension 42 of a false bottom 43 provided with a recess 44 in the center, and both the pressure sleeve 29 and the adjusting ring 30 are disposed in this recess 44.

[0019] The electrothermal actuator 15 is disposed above the false bottom 43; with its underside, it rests on the adjusting ring 30, and a slaving bracket 46 of the torsional stop 20 rests on its top. The slaving bracket 46, which is for instance an upside-down U but can also have two U-shapes extending crosswise to one another, has claws, on its axially downward-pointing ends 47, and these claws engage recesses or engage next to fixed extensions of the male-threaded part 17, and can be disengaged therefrom. Since the slaving bracket 46 is connected to the grip element 13 in a manner fixed against relative rotation, it is possible in this way, depending on the axial position of the slaving bracket 46, to achieve a torsion lock between the grip element 13 and the male-threaded part 17, or idle rotation of the grip element 13 above the male-threaded part 17. The slaving bracket 46, on its indented central region 48 with which it rests on the bottom on the actuator 15, is acted upon on top by a compression spring 49, which is braced on its other end on the grip element 13 and which is guided in an annular extension 50 of the grip element 13 that establishes the positive-engagement connection with the slaving bracket. Between the slaving bracket 46 and the grip element 13, a retaining disk 51 is held sealingly on the male-threaded part 17; the retaining disk 5 serves as an end stop for the slaving bracket 46, in its disengaged position.

[0020] The electrothermal actuator 15 is formed by an absorption actuator, preferably a metal hydride actuator, or an expansion actuator, which is shown in the drawing in the form of a diaphragm capsule 55. The actuator 55 has the property of expanding upon an increase in temperature and contracting to its original size again when the corresponding temperature is reduced. For subjecting the diaphragm capsule 55 to temperature, a heating resistor in the form of a PTC heating element 56 is disposed at one or more points on the underside of the diaphragm capsule 55. This PTC heating element 56 is disposed such that a heat transfer with the least possible loss takes place from the PTC heating element 56 to the diaphragm capsule 55. The diaphragm capsule 55 is preferably embodied such that its axially central region expands axially relative to the grip element 13, or axially relative to the adjusting ring 30 and pressure sleeve 29.

[0021] The PTC heating resistor 56 is connected electrically, in a manner not shown, to an electric controller 57 which is accommodated on a printed circuit board 58, which in the exemplary embodiment shown is accommodated in the grip element 13, directly beneath its covering. A plug socket 61 is secured to a circumferential region of the male-threaded part 17 of the closure cap 10, and its contacts, not shown, are connected electrically to the controlling circuit board 58. An adaptor cable that connects the electrical connection of the controlling circuit board 58, and thus of the actuator 15, to the applicable control elements of the motor vehicle is connected to the plug outlet 61. For instance, the triggering of the actuator 15 is effected by means of a temperature and/or pressure sensor, and this sensor picks up the temperature and/or pressure at the motor vehicle radiator container or the like.

[0022] The safety-relevant functions of the closure cap 10, in the form of adjusting the overpressure valve assembly 11 and adjusting the torsional stop 20, are as follows:

[0023] In the outset position, with the engine not running and cold, shown in FIG. 1, the diaphragm capsule 55 is in its retracted normal position, in which the slaving bracket 46 is pressed by the compression spring 49 into a position that prevents relative torsion that brings about a torsion lock between the grip element 13 and the male-threaded part 17. The overpressure valve assembly 11 is likewise pressed against the sealing seat in its outset position, that is, the overpressure valve body 22 is pressed against the sealing seat by the compression spring 28 which is normally or when installed prestressed, in such a way that the overpressure valve body 22 will open at an overpressure of approximately 1.4 bar.

[0024] When the motor vehicle engine is started, the coolant in the radiator warms up. Once the coolant reaches a temperature higher than approximately 89° C., for instance, the controller 57 on the circuit board 58 becomes active; that is, current is delivered to the PTC heating element 56 to heat it, or the PTC heating element is connected to voltage. Thus heat is transferred from the PTC heating element 56 to the diaphragm capsule 55, so that the actuator is actuated, and the diaphragm capsule 55 expands axially. The two compression springs 28 of the overpressure valve assembly 11 and 49 of the torsional stop 20 that are oriented counter to one another and both act on the diaphragm capsule 55 are adjusted in such a way that the compression spring 49 has a lesser spring force than the compression spring 28. The diaphragm capsule thus expands counter to the pressure of the compression spring 49 of the torsional stop 20 and accordingly moves the slaving bracket 46 axially up to the stop of the retaining disk 51. The slaving bracket 46 thus becomes disengaged from the male-threaded part 17, so that it is no longer possible to open the closure cap 10 because the grip element 13 is rotating idly relative to the male-threaded part 17. The opening pressure of the overpressure valve assembly 11 remains as it was.

[0025] Once the engine is switched off, the coolant temperature rises from residual heating action to over 120° C., for instance. This activates a second regulating stage in the controller 57 on the circuit board 58, so that an increased voltage is applied to the PTC heating element 56, or a greater flow of current is brought about. This means that the diaphragm capsule 55 expands further. Since the slaving bracket 46 is pressed against the stop of the retaining disk 51 (FIG. 2, right half of the section) counter to the action of the compression spring 49, it is attained that, as shown in the right half section of FIG. 3, the compression spring 28 of the overpressure valve assembly 11 is further prestressed. This prestressing of the compression spring 28 causes the opening pressure of the overpressure valve body 22 to be increased, for instance to approximately 2.0 bar. This safety stage persists until such time as the coolant temperature has dropped, which affects the triggering of the PTC heating element 56 and the heating and cooling down of the diaphragm capsule 55.

[0026] In the exemplary embodiment shown, the controller 57 is accommodated physically in the form of the circuit board 58 in the grip element 13. In another exemplary embodiment, not shown, of the present invention, the controlling circuit board 58 is provided in the plug outlet 61, or in a plug part of the adaptor cable, either near the closure cap 10 or near the connection with the motor vehicle.

Claims

1. A closure cap (10) for a fixed neck of a container, in particular a motor vehicle radiator, having a cap outer part (12), which has a closure element (17) that can be joined to a container neck and a grip element (13) retained rotatably relative to it, between which a torsional stop (20) is provided that has a coupling insert (46), which can be axially engaged and disengaged with and from the closure element (17) and is held in the grip element (13) in a manner fixed against relative rotation, for connecting the closure element and grip element in a way that is releasably fixed against relative rotation, and having a cap inner part (14), which has a fluidic connection between the container interior and the container exterior and a valve assembly (11) for enabling and blocking the fluidic connection, and a valve body (22) of the valve assembly (11) that can be moved back and forth is pressed toward the container interior against a sealing seat (21) on the cap inner part (14) with prestressing, in such a way that if a limit value of the container interior pressure is exceeded it can lift from the sealing seat (21), characterized in that an actuator (15) that is capable of expansion from heat is provided both for axial engagement and disengagement of the coupling insert (46) of the torsional stop (20) and for adjusting the prestressing with which the valve body (22) of the valve assembly (11) is pressed against the sealing seat (21).

2. The closure cap of claim 1, characterized in that the actuator (15) is formed by an electrically heatable element of expansion material.

3. The closure cap of claim 1, characterized in that the actuator (15) is formed by an electrically heatable absorption actuator, preferably a metal hydride actuator.

4. The closure cap of at least one of the foregoing claims, characterized in that the actuator (15) is in operative communication with an electrical heating resistor (56), preferably a PTC resistor, whose trigger voltage is picked up by a temperature and/or pressure sensor associated with the container.

5. The closure cap of claim 4, characterized in that the electrical heating resistor (56) is located on the underside of the actuator (15).

6. The closure cap of at least one of the foregoing claims, characterized in that the actuator (15) is disposed inside the closure element (17), oriented toward the grip element (13).

7. The closure cap of claim 4, characterized in that an electronic triggering unit (57, 58) is provided between the temperature and/or pressure sensor and the electrical heating resistor (56).

8. The closure cap of claim 7, characterized in that the electronic triggering unit (57, 58) is disposed in the grip element (13).

9. The closure cap of claim 7, characterized in that the electronic triggering unit (57, 58) is disposed in a plug of an electrical connecting line leading to the closure cap.

10. The closure cap of claim 9, characterized in that the plug is connected to a counterpart plug (61) on the closure cap.

11. The closure cap of at least one of the foregoing claims, characterized in that the valve body (22) is prestressed, facing away from the actuator (15), by a spring (28) which is braced, on its end remote from the valve body (22), on a pressure piece (29, 30) that in turn rests on the actuator (15).

12. The closure cap of at least one of the foregoing claims, characterized in that the torsional stop (20) has a bracket (46), which rests by spring action on the actuator (15) and has terminal prongs (47), which can brought lockingly into an engagement with the male-threaded part (17) and can be released unlockingly.