State of the art Particularly in a large motor vehicle it is important to be able to ensure effective cooling in various operating situations. Increased engine powers in combination with limited space for the radiator have made it necessary to try to use available radiators more effectively. This need has been further accentuated by the fact that the radiator not only has to cool the engine but is also used to remove heat from other components of the vehicle. An example of such a component is a hydraulic retarder which is coupled to the vehicle and which may in a short time generate large amounts of heat which have to be dissipated quickly by means of the ordinary radiator.

One way of improving the effectiveness of the radiator's cooling capacity is to improve the air flow through it. This can be done by providing after the radiator an enclosed duct in which to place the cooling fan in order to promote an effective air flow in the duct and hence also through the radiator. What has thus been aimed at is an unbroken flow duct to the fan, which is achieved by making the fan run in a fan ring which is sealed relative to the radiator by means of a seal.

One of the difficulties in this respect is that the engine and the radiator need a certain mutual mobility, because the fan is usually mounted firmly on the engine, whereas the radiator is mounted firmly on the vehicle's chassis. Large relative movements between the engine and the chassis normally occur during vehicle operation. This mobility problem has often been solved by means of an open gap between the fan and the radiator, but the increasing need for more effective air flow has resulted in this gap being closed by a seal between the fan ring and a fan housing fastened to the radiator. This seal has been made rather pliable in order to provide good mobility but it has been found that

displacement movements and large negative pressure in the flow duct have sometimes resulted in the front portion of the seal becoming deformed and being sucked in towards the fan, resulting in considerable damage, substantially inferior sealing function and inferior cooling.

Object of the invention The object of the invention is to provide a seal which by better design performs its function better and does not impair vehicle operation.

Brief description of the invention This object is achieved by the seal being designed in accordance with the characterising part of patent claim 1. Providing the seal with a valve element of the type indicated is found to result not only in the seal maintaining its shape even during large mutual displacements between the seal and the radiator but also in the possibility of pressure relief due to the opening of a path for extra air. Although this pressure relief means a somewhat smaller air flow for a short time, the seal normally soon returns to its sealing position and the air flow to normal.

According to an advantageous embodiment there is on the seal a valve element in the form of at least one finger which extends beyond the periphery of the flange portion, is intended for contact with the fan housing and constitutes an extension of a radially oriented reinforcement arranged on the flange portion. This means that the seal can be made flexible but still maintain its shape in various mutual positions between it and the radiator.

Further features and advantages of the invention are indicated in the accompanying patent claims and the embodiment described below.

List of drawings The drawings illustrate an embodiment as follows: Fig. 1 shows schematically a fan arrangement on an engine with associated radiator, Fig.2 shows a fan arrangement according to Fig. 1 as seen from the rear, without the engine, Fig.3 shows a section through a fan ring with fitted seal, Fig.4 shows a view from the radiator of an upper portion of a seal according to the invention, Fig.5 shows a section V-V in Fig.4, and Fig.6 shows a section corresponding to that in Fig.5, together with a portion of the fan housing.

Description of an embodiment According to Fig. 1, a vehicle engine 1 is provided with a cooling fan 2 to engender good air flow through a radiator 3 situated in front of the engine and the cooling fan. To ensure effective air flow, the cooling fan 2 runs in a conventional manner within a fan ring 4 which is mounted on the engine 1 by means of a number of brackets 5 and which therefore follows the engine movements relative to the radiator 3, which is mounted firmly on the vehicle's chassis.

With the object of effectively leading cooling air into the fan ring 4, the radiator 3 is provided on its side facing the fan 2 with a fan housing 6 which has in the direction of the fan 2 a tapering, substantially conical portion 7.

Between the fan ring 4 and the fan housing 6 there is a gap closed by a circular seal 8 which is fitted to the fan ring 4, widens towards the radiator 3 and has its end which faces the latter reaching in over and abutting against the outside of the conical portion 7 of the fan housing 6. Making the seal 8 sufficiently thin and of elastic material such as rubber

ensures that the sealing function is maintained when the engine and the radiator during vehicle operation shift mutually within certain limits.

The arrangement depicted in Fig. 1 may in practice be designed according to Fig.2, in which for the sake of clarity the engine 1 has been omitted.

The seal 8 may have along much of its circumference a cross-sectional shape according to Fig.3. A fastening portion 9 holds the seal 8 firmly on the fan ring 4 and provides a uniform transition between the seal and the fan ring. A substantially conical flange portion 10 connected to the fastening portion 9 has the purpose of its inside providing a seal relative to the conical portion 7 of the fan housing 6. It is in this respect desirable that the flange portion 10 be flexible in order to seal properly, but not so pliable as to be quite easily sucked in between the fan housing and the fan ring. There may possibly be a number of radial reinforcements distributed in the circumferential direction in the form of thickenings on the side of the flange portion 10 which faces the engine, in order to stiffen the flange portion 10 with minimum consumption of material.

According to the invention a particularly advantageous version is obtained if the seal 8, as illustrated in Fig.2, is provided in at least an upper portion with a number of specially designed reinforcements 11 which extend beyond the periphery of the flange portion 10.

These reinforcements 11 are radially oriented and situated in the circumferential direction at mutual spacings from one another.

As shown in more detail in Figs. 4 and 5, each of these reinforcements 11 has a finger 12 which extends beyond the flange portion 10. The result is that the seal 8 is locally extended both radially and axially.

This has the advantage that during such large movements between the engine and the radiator that the flange portion 10 locally slides away from the conical portion 7 of the fan housing 6 (see Fig.6) the fingers 12 can maintain contact with the conical portion 7 and hence maintain the shape of the flange portion 10 and prevent its being sucked in towards the fan. The design adopted in this case also means that the flange portion 10, the finger

12 and the conical portion 7 constitute valve elements in a valve 13 which can be opened to let air in from outside according to the arrow 14. The resulting pressure compensation stabilises the flange portion 10 and facilitates reversion to normal position when the valve 13 closes.

The width of the fingers 12 in the circumferential direction may be varied according to need, as also the number of reinforcements 11, which are advantageously made integral with the remainder of the seal 8 and may be situated all round the seal 8 or only locally at one or more points, although the greatest need for reinforcements according to the invention is normally on the upper section of the seal 8 in the version depicted in Fig.2.

The valve 13 may in principle also take the form of one or more apertures in the flange portion 10 or in the conical portion 7, in which case these apertures are closed or opened during mutual movement between the conical portion 7 and the flange portion 10. Many versions are possible with respect to the size, number and positioning of the apertures.