DE20023115U1 - Thermostatic valve has plastic housing in which valve plate is mounted which is biased towards closed position by spring held in place by metal mounting with two arms which have hooked ends with convex transverse surface - Google Patents

Abstract

The thermostatic valve has a plastic housing (1) in which a valve plate (11) is mounted which is biased towards the closed position by a spring (8). This is held in place by a metal mounting (7) with two arms (13) which have hooked ends (14). These have a convex transverse surface.

Description

Geiger Technology GmbH

82467 Garmisch-Partenkirchen GE 00616 GM

Thermostatic valve

The invention relates to a thermostatic valve with a housing part made of plastic with a valve opening which is surrounded by a valve seat, with a thermostat element with a displaceably held valve plate which is acted upon by a spring in the direction of the valve seat, the spring being supported on an abutment preferably made of metal which has two opposing legs with essentially hook-shaped angled fastening sections at the free ends which engage in window-like openings of two webs formed on the housing and rest on the bottom wall of the openings.

Such a thermostatic valve is arranged, for example, in the cooling circuit of motor vehicles and releases the valve opening when the coolant has reached a certain minimum temperature.

A thermostatic valve of the type mentioned above is known from EP 0 600 150 B1. In this valve, short webs with window-like recesses are formed on the housing, into which hook-shaped fastening sections on the free ends of the legs of the abutment of the spring acting on the valve plate engage in such a way that only tensile forces act on them, so that a uniaxial stress state is created while avoiding bending moments, through which the dimensional stability and the creep strength of the housing part are significantly increased. This is intended to prevent the webs of the valve housing from breaking as a result of the

The loads resulting from the spring force are avoided, whereby the high operating temperatures also place a strain on the valve housing.

When the thermostatic element moves the valve plate back against the force of the spring pressing the valve plate against the valve seat when the opening temperature is reached, the abutment on which the spring is supported can perform a slight tilting movement to a plane running through the two legs of the abutment. In this case, the fastening sections of the legs of the abutment also tilt in the openings of the webs of the valve housing, which leads to an off-center load on the webs and to high edge pressure, which can damage the webs and make the valve inoperable.

The present invention is based on the object of improving a thermostatic valve of the type in question so that it can better withstand the loads that occur.

This object is achieved according to the invention by the features of claim 1.

Advantageous embodiments of the invention are characterized in the subclaims.

The invention provides that the fastening sections of the legs of the abutment, which are hook-shaped in longitudinal section, have a convexly curved underside or support surface in the width direction with respect to the bottom wall of the window-like openings in the webs. Since the abutment with the two legs and their fastening sections are expediently made from a metal sheet, this means that the fastening sections are formed by a sheet metal section that is convexly curved in the width direction, i.e. the underside and the top of the fastening sections have a matching convex curvature with respect to the support.

This design ensures that the abutment centers itself, i.e. that it automatically returns to the central starting position in the event of a lateral deflection, whereby the curvature of the underside of the fastening sections prevents increased edge pressure from occurring during the deflection, which could damage the webs.

Preferably, it is also provided that the bottom of the window-like openings of the webs of the housing also has a curvature in the width direction, which is flatter than the fastening sections at least in the edge areas. The curvature of the bottom of the window-like openings forming the bearing surface of the fastening sections can also contribute to the self-centering of the abutment.

In more detail, it is proposed that the fastening sections of the legs of the abutment have an arc shape that is symmetrical to the central longitudinal axis of the legs and that this arc shape contains a circular arc section, which in the case of a thermostat valve for the cooling circuit of a motor vehicle preferably has a radius of approximately 10 to 13 mm. As already mentioned above, it can be provided that the lateral end sections of the fastening sections are bent more strongly.

The window-like openings into which the fastening sections of the legs of the abutment engage expediently have a longer extension in the width direction than the fastening sections. With regard to the curvature of the base of the window-like openings, it is proposed that this has an arched shape symmetrical to the central longitudinal axis, with a circular arc with a radius of about 15 mm being particularly suitable for a thermostatic valve for a cooling circuit.

Thus, the radius of the bottom of the window-like opening is preferably larger than that of the fastening sections of the legs of the abutment.

Although the above size ratio is preferred, it is within the scope of the invention that the radius of a part of the fastening sections that is central in the width direction corresponds to that of the bottom of the window-like openings, and that the lateral ends of the fastening sections are bent upwards more, i.e. in the direction of the valve seat. The radius of this central part can also be oo. This distributes the bearing pressure over a larger width, while at the same time maintaining the self-centering effect.

Further details of the invention emerge from the following description of a preferred embodiment of the invention and from the drawing. In the drawing:

Fig. 1 is a vertical section through a thermostatic valve;

Fig. 2 is a perspective view through the area in which a hook-shaped fastening section of a leg of the abutment engages in a window-like opening of a housing web;

Fig. 3 is a side view of the arrangement according to Fig. 2 and

Fig. 4 is a section along the line A-A in Fig. 3.

Fig. 1 shows the essential parts of a thermostatic valve. A housing 1 made of plastic has a tubular hose connection piece 2, an inwardly projecting pin 4 serving as an abutment for a thermostat element 3, an annular valve seat 5 and two diametrically opposed webs 6 which project downwards in Fig. 1 and serve to attach an abutment 7 made of metal for a spring 8.

The thermostat element 3 contains a piston 9 which engages in a bore 10 of the pin 4 and is extended when a heat-sensitive expansion material arranged in the thermocouple is heated. As a result, a valve plate 11 held by the thermostat element 3, which is normally pressed against the valve seat 5 by the compression spring 8, is pushed back, whereby the

- 5 valve opening
is released.

The compression spring 8 is supported on the abutment 7, from whose base plate 12 two diametrically opposed strip-shaped legs 13 are angled in the direction of the valve opening, which at their free ends merge into hook-shaped fastening sections 14. The abutment 7 with its legs and fastening sections is made in one piece from a metal sheet.

The webs 6 each have a recess which is approximately U-shaped in horizontal section on the inner sides facing each other, into which the legs 13 with the fastening sections 14 are inserted from below, whereby these are pressed together in a spring-loaded manner at the two opposite groove bottoms until the fastening sections 14 reach window-like openings 15 through the remaining wall of the webs 6. Here the fastening sections 14 snap in, whereby the fastening sections 14, which are angled downwards in a hook shape, rest on the bottom 17 of the window-like openings.

Figures 2 to 4 show further details of the design of the fastening sections 14 and the window-like openings 15.

The two-sided legs 13 of the abutment 7 have a flat strip shape, which at the free end merges into a curvature of the fastening section 14 directed upwards in the width direction A. As shown in particular in Fig. 3, the central region of the fastening sections 14 is curved upwards in a circular arc symmetrically to the longitudinal axis 18, with the lateral end sections 19 being bent up more strongly or curved upwards.

The bottom wall 17 of the window-like openings 15 is also curved upwards in a circular arc shape symmetrically to the central longitudinal axis 18, with a corresponding radius of 15 mm being realized in the embodiment shown.

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The curved mounting of the fastening sections 14 on the bottom wall of the window-like openings 15 ensures that the abutment 7 centers itself automatically. Edge pressure cutting into the bottom wall is reliably avoided.

Claims (9)

1. Thermostatic valve, with a housing part made of plastic with a valve opening which is surrounded by a valve seat, with a thermostat element with a displaceably held valve plate which is acted upon by a spring in the direction of the valve seat, which is supported on an abutment made of metal, which has two opposite legs with essentially hook-shaped angled fastening sections at the free ends, which engage in window-like openings of two webs formed on the housing and rest on the bottom wall of the openings, characterized in that the fastening sections ( 14 ) of the legs ( 13 ) of the abutment ( 7 ) have a convexly curved bearing surface in the width direction (A). 2. Thermostatic valve according to claim 1, characterized in that the fastening sections ( 14 ) have an arc shape symmetrical to the central longitudinal axis ( 18 ). 3. Thermostatic valve according to claim 2, characterized in that the arc shape contains a circular arc section with a radius of about 10 to 15 mm. 4. Thermostatic valve according to one of claims 1 to 3, characterized in that the lateral end sections ( 19 ) of the fastening sections ( 14 ) are bent upwards to a greater extent. 5. Thermostatic valve according to one of claims 1 to 4, characterized in that the window-like openings ( 15 ) have a longer extension in the width direction (A) than the fastening sections ( 14 ). 6. Thermostatic valve according to one of claims 1 to 5, characterized in that the bottom wall ( 17 ) of the window-like openings ( 15 ) has a concave curvature in the width direction (A) which is flatter than the curvature at least in the region of the lateral end sections ( 19 ) of the fastening sections ( 14 ) of the legs ( 13 ) of the abutment ( 7 ). 7. Thermostatic valve according to claim 6, characterized in that the bottom wall ( 17 ) of the window-like openings ( 15 ) has a circular arc shape symmetrical to the central longitudinal axis ( 18 ). 8. Thermostatic valve according to one of claims 1 to 7, characterized in that the radius of the circular arc section of the bottom wall ( 17 ) corresponds to that of the fastening sections ( 14 ) in a central region. 9. Thermostatic valve according to one of claims 1 to 7, characterized in that the radius of the circular arc section of the bottom wall ( 17 ) is larger than that of the fastening sections ( 14 ).