DESCRIPTION

The present invention relates to an apparatus for actuating and controlling the rotation, about their axis, of fans for cooling the cooling fluid contained in the radiator of operating machines and/or vehicles, in particular agricultural tractors and off-road vehicles.

It is known that the operation of operating machines and vehicles by means of a combustion engine involves the need to cool the latter by means of a cooling fluid which is stored inside a cellular radiator and recirculated through the engine; the cooling fluid is in turn cooled by the ambient air which is forced to pass through the radiator by the sucking action of a rotating fan.

Taking as a reference point the normal front part of the machine/vehicle the three elements are axially arranged with the radiator at the front, engine behind it and fan arranged between the two.

It is also known that, in the technical sector of vehicles which are generally used in conditions where there is a large quantity of loose debris, as in the case of agricultural tractors or vehicles intended for off-road use, but also operating machines which work under stationary conditions, this loose debris tends to be deposited on the cellular surfaces of the radiator containing the vehicle cooling fluid, causing blockage thereof and therefore a reduced and/or no cooling of the fluid, with consequent overheating of the engine.

The main cause of said accumulation of debris on the radiator is the forced air flow of the fan which is arranged behind the radiator in the direction of travel of the vehicle and connected to the driving shaft of the vehicle, said fan, when rotated, drawing in the air and forcing it to pass through the radiator, causing dissipation of the heat from the cooling fluid contained inside it, which is at a higher temperature, into the external environment, which is at a lower temperature.

It is also known that, under normal operating conditions, said fan must be made to rotate only when a definite predefined temperature of the cooling fluid is reached, this being detected by means of a thermostat .

In greater detail it is required that a motor vehicle fan should be able to draw air from the radiator towards the combustion engine:

- in a small amount for cooling in low external temperature conditions,

- in large amounts when there are higher external temperatures or when the vehicle is used in demanding conditions resulting in overheating of the engine, but also

- air must be temporarily forced onto the radiator in the opposite direction in order to clean it of the impurities which have accumulated during normal operation .

A fan controlled by an apparatus according to the preamble of Claim 1 is known from US 2 788 775 A.

The technical problem which is posed therefore is that of providing an apparatus for controlling the rotation about their axis of fans for cooling the cooling fluid contained in the radiator of operating machines and/or vehicles, in particular agricultural tractors and off-road vehicles, so as to obtain a rotation suitable for cooling the cooling fluid contained in the radiator and alternatively a rotation suitable for causing cleaning of the cells of the radiator if clogged with dirt.

In connection with this problem it is also required that this apparatus should have small dimensions, be easy and inexpensive to produce and assemble and be able to be easily installed at any user location using normal standardized connection means.

These results are achieved according to the present invention by an apparatus for controlling the rotation, about their axis, of fans for cooling the cooling fluid contained in the radiator of operating machines and/or vehicles, in particular agricultural tractors and off-road vehicles, according to the characteristic features of Claim 1.

Further details may be obtained from the following description of non-limiting examples of embodiment of the subject of the present invention, provided with reference to the accompanying drawings, in which:

Figure 1 : shows a cross-sectional view along a vertical plane of a first embodiment of the apparatus according to the present invention mounted on a fixed support ;

Figure 2 : shows a cross-sectional view, similar to that of Fig. 1, of a second embodiment of the apparatus mounted on the body of the water pump of the combustion engine;

Figs . 3a, 3b : show cross-sectional views of the apparatus in the conditions where the fan is rotating respectively for cooling and cleaning the radiator; and

Figs . 4a, 4b : shows respectively, a partially sectioned view of a further embodiment of a variant of the apparatus with corresponding enlargement.

As shown in Fig. 1 and assuming solely for the sake of easier description and without any limitation of meaning a pair of reference axes, i.e. in a longitudinal direction X-X, for convenience coinciding with the axis of rotation of the fan 1, and transverse/radial direction Y-Y orthogonal to the preceding direction, as well as, with reference to the direction of travel of a vehicle indicated by the arrow "A", a front part corresponding to the position of a radiator 2 and a rear part corresponding to the position of the combustion engine, represented by its body part 12, the fan 1 is arranged behind the radiator 2 and in front of the said engine.

According to the above layout the apparatus according to the invention comprises essentially:

- means 100 for generating a rotational movement, comprising :

- means for receiving a rotational movement from a movement source, in the example of Fig. 1 consisting of a primary pulley 110 mounted on a fixed support 10 attached to a fixed part 12 of the engine; a bearing 11 being arranged between the primary pulley 110 and the support 10; the pulley is rotationally driven by a belt 111 connected to the combustion engine;

- a fixed housing 140 which is formed by two half- bodies 140a and 140b and inside which the following are arranged in an oil bath:

- a primary gearing 120, coaxial with the primary pulley 110 to which it is rotationally connected and provided with a radial toothing 121; the gearing 120 is supported by bearings 120a integral with the housing 140; according to a preferred embodiment the connection between the gearing and the pulley is realized by means of a resilient coupling 125 able to take up any assembly tolerances;

- a secondary gearing 130, rotating on an axis parallel to the axis of the first gearing 120 and in turn supported by bearings 130a integral with the housing 140 and provided with a radial toothing 131 designed to mesh with the toothing 121 of the primary gearing 121;

- a first electromagnetically controlled friction coupling 200 comprising:

- a first electromagnet 210 fixed to the housing 140 and inserted inside a hollow seat of a first rotor 220 which has a radial surface formed as a pulley 221 and is mounted on a first bearing 230a keyed onto an axial extension 122 of the primary gearing 121; an armature 230 is arranged facing the rotor and on the outside thereof according to the layout shown and is in turn connected by means of a resilient membrane 231 to a first disc 232 mounted on the axial extension 122 of the primary gearing 120; the membrane 231 is designed to allow a displacement, in the longitudinal direction X-X, of the armature 231, but prevent relative rotation of the two parts. Preferably both the radial cross-section of the rotor 220 and the armature 230 have openings which are designed to deviate suitably the path of the magnetic flux in order to obtain maximum coupling efficiency.

- a second electromagnetically controlled friction coupling 300 comprising:

- a second electromagnet 310 fixed to the housing 140 and inserted inside a hollow seat of a second rotor 320 which has a radial surface formed in the manner of a pulley 321 and is mounted on a second bearing 330a keyed onto an axial extension 132 of the secondary gearing 130; a second armature 330 is arranged facing the rotor 330 and on the outside thereof according to the layout shown and is in turn connected by means of a resilient membrane 331 to a second disc 332 mounted on the axial extension 132 of the secondary gearing 130; the membrane is designed to allow a displacement of the armature in the axial direction X-X, but prevent relative rotation of the two parts.

Preferably both the radial cross-section of the rotor 320 and the armature 330 have axial openings which are designed to deviate suitably the path of the magnetic flux in order to obtain maximum coupling efficiency;

- a secondary belt 50 mounted on the pulleys 221, 231 of the first rotor 220 and the second rotor 320, respectively;

- a hub la attached to the first rotor 220 of the first coupling 200 and integral with the fan 1.

As a result of this configuration:

the primary gearing 120 always rotates with a first direction of rotation in the same sense/opposite sense with respect to that of the primary pulley 110 by means of which it is rotated;

the secondary gearing 130 is always rotating, driven by the primary gearing 120 via the teeth 121,131; the engagement between the two gearings results in a direction of rotation of the secondary gearing 130 opposite to that of the primary gearing 120;

- when the first coupling 200 and second coupling 300 are disengaged, the fan 1 is at a standstill in the idle condition, not being connected to any rotating element ;

- when the first coupling 200 is activated by the excitation of the electromagnet 210, which recalls the armature 230 against the rotor 220, both the said rotor and the second rotor 320 of the second coupling 300 are made to rotate, this however having no effect on the rotation of the fan, which therefore rotates driven by the primary gearing 120 and in the same sense as the sense of rotation of the latter, for example (Fig. 3a) so as to draw air from the outside in order to cool the radiator 2;

- when the second coupling 300 is activated by excitation of the electromagnet 310, which recalls the armature 330 against the second rotor 320, both the said rotor and the first rotor 220 of the first coupling 200 are made to rotate by means of the belt 50; consequently, the fan 1 rotates in the same sense as the sense of rotation of the secondary gearing 130, for example (Fig. 3b) so as to blow air onto the radiator from the inside and clean the cells clogged with dust .

As shown in Fig. 2, it is envisaged that the apparatus according to the invention may be applied to the pump 20 for recirculating the cooling fluid of the combustion engine; in this case the primary pulley 110 is mounted on the shaft 22 of the pump via a bearing 21; with the fan coaxial with the primary gearing the operating principle is similar to that already described above and cited here.

Still with reference to Fig. 2 it is envisaged, by way of a variant, that the hub la of the fan 1 may be mounted coaxially with the secondary gearing 130; in this case rotation of the fan is performed by the rotor 320 of the second coupling 300, consequently:

- activation of the first coupling 200 causes a rotation of the fan 1 in the same sense as that of the primary pulley 110;

- activation of the second coupling 300 causes a rotation of the fan in the opposite sense to that of the primary pulley 110.

As shown in Figs. 4a, 4b, a further variation of embodiment is envisaged where the apparatus comprises a third coupling 400, preferably of the Foucault or eddy current type, arranged between the first coupling 200 and the hub la of the fan 1.

The coupling comprises a disc 410 in the thickness of which a conductive element 411 is inserted; the disc 410 has an axial sleeve 410a keyed onto the primary gearing 120 so as to form the driving member of the coupling;

a support 413 is mounted, in an axial position opposite and on the inside with respect to that of the disc 410, on the outer race of a bearing 413a, the inner race of which is keyed onto the axial sleeve 410a of the disc 410; the support 413 carries permanent magnets 414 arranged axially opposite the conductive element 411.

An auxiliary armature 414 is attached to the support

413 by means of a resilient membrane 414a and is designed to be recalled against the primary rotor 220 by the excitation of the electromagnet 210 of the first coupling 200.

In this configuration, therefore, it is envisaged that the electromagnet is formed by two separate windings which are designed to convey two different excitation currents, respectively: a greater current, for recalling the first armature 230 which transmits the rotation of the belt 111 to the fan 1, and a smaller current, for recalling the auxiliary armature

414 of the Foucault coupling 400 so as to transmit to the fan 1 a lower speed than that of the said belt 110; said lower speed being determined by the dimensions of the Foucault coupling 400.

It is envisaged, however, that the electromagnet control system may comprise two separate electromagnets which can be excited with different currents . Although not shown, it is envisaged that a third eddy current coupling may be provided also in the case of a fan coaxial with the secondary gearing; the third coupling assembly is not described here in further detail, being entirely similar to that already described for the case of a fan coaxial with the primary gearing.

As shown in the same Figs. 4a, 4b, further auxiliary means 500 are provided for forming a fail-safe element, i.e. these being designed to ensure a minimum speed of rotation of the fan also in the case of electrical faults or faults of the electronic control system or the secondary belt 50.

Said means 500 comprise a support 510 which is integral with the hub la of the fan and which has, fixed thereto, permanent magnets 511 arranged in a radial position so as to be axially opposite, on an axially outer side, to the conductive element 411 of the disc 410 keyed onto the primary gearing 120.

Since the disc 410 is always rotating, eddy currents are produced and these induce an electromagnetic field between the disc 410 and the magnets 510 which cause rotational driving of the hub la and therefore the fan 1.

Since the speed of rotation is determined by the dimensions of the permanent magnets of the hub, the dimensions may also be very small, a very low speed of rotation being required only for safety purposes. The fail-safe means 500 may similarly be provided in the case of a fan coaxial with the secondary gearing with third Foucault coupling.

For all the modes of operation described in connection with the various configurations of the apparatus, the orientation of the blades will be adapted to the type of suction/blowing operation which is to be obtained.

It is therefore clear how with the apparatus according to the invention it is possible to ensure rotation of the fan for cooling and rotation of the fan for cleaning the radiator with a single fan and without the need for auxiliary electric motors.

In addition to this, owing to the particular arrangement of the couplings with parallel axes, it is possible to limit the axial dimensions of the apparatus such that it may be advantageously applied to vehicle engine compartments where there is a small amount of space.

In variations of embodiment it is possible to obtain several speeds of rotation of the fan so that the quantity of air which passes through the radiator may be adapted to the different conditions of use.

Although described in connection with a number of embodiments and a number of preferred examples of embodiment of the invention, it is understood that the scope of protection of the present patent is determined solely by the claims below.