"Cooling pump with a coupling unit"

[0001] The present invention relates to a mechanical cooling pump, in particular for use in motor vehicles.

[0002] It is known that the cooling pump is the main component of the cooling circuit for thermal motors, especially in the vehicles sector. Particular attention is therefore paid to the correct design of such components and the continual improvement of performance of the same.

[0003] In particular, particular care is taken to adjust the pump flow to the working conditions of the thermal motor, so that the flow can vary in relation to the need for the motor to dissipate thermal energy, at the same time maintaining optimal functioning in the other working conditions .

[0004] Solutions exist in which such adjustment is performed by using partialisation valves, as for the pump described in the document PCT/IT2009/000269, in the Applicant's name.

[0005] Sometimes however, the use of electric adjustment systems which for example have shorter response times may be useful.

[0006] In such regard, mechanical cooling pumps exist fitted with an electromagnetic coupling device placed between the pulley and the pump shaft.

[0007] However, such solutions often raise problems of reliability and design of the components of the coupling device, related mainly to the dimensions.

[0008] The purpose of the present invention is to make a mechanical cooling pump, in particular for use in motorised vehicles, able to satisfy the aforementioned requirements and overcome the drawbacks spoken of in relation to the prior art.

[0009] Such purpose is achieved by a cooling pump made according to claim 1.

[0010] The characteristics and advantages of the cooling pump according to the present invention will be evident from the description given below, made by way of a non- limiting example, according to the appended drawings, wherein :

[0011] - figure 1 shows an axonometric cross-section view of a cooling pump according to one embodiment of the present invention;

[0012] - figure 2 shows the pump in figure 1 in separate parts ;

[0013] - figure 3 shows a cross-section view of the pump in figure 1 in an active functioning configuration;

[0014] - figure 4 shows a cross-section view of the pump in figure 1 in an inactive non-functioning configuration; [0015] - figure 5a shows an axonometric view of an engagement device of the pump according to the present invention, according to one embodiment,

[0016] - figure 5b shows a longitudinal cross-section of the engagement device in figure 5a;

[0017] - figure 6 shows a cross-section axonometric view of an actuation device of the pump according to the present invention, according to one embodiment; and

[0018] - figure 7 shows a cross-section view of a pump according to the present invention according to a further embodiment .

[0019] According to one embodiment of the present invention, a mechanically functioning cooling pump 1, in particular for vehicles, comprises a pump body 2, generally made in a single piece, provided internally with a through compartment comprising a shaft compartment 4a and a main compartment 4b, in sequence, from one side to the other of the body 2.

[0020] The pump 1 further comprises a shaft 6 housed in the inner compartment of the body 2, rotating around a rotation axis Z, projecting forwards into the main compartment 4b, supported by roller or plain bearings in the shaft compartment 4a and such as to project rearwards from the shaft compartment 4a.

[0021] The pump 1 is further connected to a pulley 8, coaxially attached to the shaft 6, at the end projecting rearwards from the shaft compartment 4a, to which a belt or chain may be engaged for rotation of the shaft.

[0022] The pump 1 further comprises a rotor 10, supported in a rotatable manner by the pump body 2, coaxial to the rotation axis Z of the shaft 6.

[0023] Preferably, the rotor 10 comprises a rotor body in one piece.

[0024] For example, the rotor body comprises:

[0025] - an annular skirt 14, radially distanced from the rotation axis Z, having an axial extension such as to at least partially overlap the section of shaft 6 projecting into the main compartment 4b;

[0026] - a cap 16 closing the skirt 14 at the front ;

[0027] - a plurality of paddles 18, projecting axially and/or radially from the cap 16, to act on the cooling liquid .

[0028] Preferably, the cap 16 is provided with an annular engagement surface 16a on the inside, in other words facing towards the main compartment 4b, for example in the shape of a circular crown coaxial to the rotation axis Z lying on a plane orthogonal to the rotation axis Z or, in one embodiment variation, in the form of a tapered surface coaxial to the rotation axis Z.

[0029] Preferably, the pump body 2 comprises an annular rotor support wall 20, radially distanced from the skirt 14 of the rotor, at least partially overlapping it axially .

[0030] The pump 1 further comprises means of support in rotation of the rotor, suitable to support the rotor to permit its rotation.

[0031] For example, said means of support in rotation comprise a roller bearing 30, housed between the rotor support wall 20 and the skirt 14. Preferably, the roller bearing 30 is liquid proof between the inner ring (attached to the skirt 14 of the rotor) and the outer ring (supported by the rotor support wall 20) , at least on the paddle side.

[0032] According to a further embodiment (figure 7) the pump 1 comprises a seal 100, for example a contact or labyrinth seal, placed between the outside and the main compartment 4b. For example the seal 100 is next to the roller bearing 30 towards the outside.

[0033] This way, the main compartment 4b of the pump body is sealed off from the environment outside the rotor, where the cooling liquid is located.

[0034] The pump 1 further comprises a coupling unit able, upon command, to release the rotor 10 from the shaft 6, housed in the main compartment 4b of the pump body.

[0035] The coupling unit comprises an engagement device 40 comprising an engagement plate 42 having an engagement surface 42a, positioned on a plane orthogonal to the rotation axis Z, facing towards the rotor 10 and, in particular, facing the engagement surface 16a of the skirt 14 of the rotor.

[0036] Preferably, the engagement surface 42a is made of abrasive material; preferably, the entire engagement plate 42 is made from abrasive material.

[0037] The engagement device 40 further comprises a support body 44 comprising a hub 46 attached coaxially to the shaft 6, and in particular to the section of the shaft projecting into the main compartment 4b, and a crown 48, connected to the hub, for example by spokes, projecting radially from it.

[0038] At least in the portion radially overlapping the engagement plate 42, the crown 48 is axially distanced from the same.

[0039] Preferably, moreover, the crown 48 has a radial extension equal to that of the engagement plate 42.

[0040] Moreover, the engagement device 40 comprises an elastic plate 50 positioned between the engagement plate 42 and the crown 48 of the support body 46.

[0041] The elastic plate 50 is joined to the support body 46 of the engagement device 40 and in particular attached to its hub 46, for example by means of threaded elements 52.

[0042] Consequently, the elastic plate 50 has a fixed area 50a corresponding substantially to the area attached to the hub 46, which is practically non-deformable, and a deformable area 50b which extends radially from the fixed area 50a, deformable in a more accentuated manner than the fixed area.

[0043] In particular, the deformable area 50b is attached to the engagement plate 42 and an axial deformation of said deformable area 50b causes a rearward axial movement of said deformable plate 42 from the rest position.

[0044] At least in the portion radially overlapping the deformable area 50b of the elastic plate 50, the crown 48 is axially distanced from it.

[0045] Preferably, the elastic plate 50 is made in a single piece, for example from steel.

[0046] Preferably, moreover, the elastic plate has three lobes and is provided with a window 54 to facilitate its deformation .

[0047] The engagement device 40 is magnetically reactive; in other words, under the effect of a magnetic field generating a force of axial attraction, the deformable area of the elastic plate deforms, making the engagement plate move backwards axially from the position assumed in the active functioning configuration. [0048] To such purpose, the engagement plate and/or elastic plate are made in ferromagnetic material or with inserts in ferromagnetic material, preferably steel.

[0049] Furthermore, the coupling unit comprises an actuation device 70 able to electrically generate a magnetic field suitable for activating the engagement device 40.

[0050] The actuation device 70 comprises an electromagnet consisting for example of an outer cage 72, an inner cage 74 and a copper coil 76 positioned between the cages.

[0051] The actuation device 70 is housed in the main compartment 4b of the pump body 2, coaxially to the shaft 2 which traverses it, attached to the pump body, in other words cannot be dragged in rotation by the shaft.

[0052] In addition, the actuation device 70 is preferably positioned on the side opposite the rotor in relation to the engagement device 40, that is to say so that the engagement plate 42 is situated in the engagement area 16a of the rotor and the coil 76.

[0053] According to one embodiment, the pump 1 further comprises a secondary roller bearing 90, the outer ring of which is supported by the pump body 2, inside the main compartment 4b, and the inner ring of which may be engaged by the crown 48 of the engagement device 70, to support it in rotation. [0054] In an active or functioning configuration, the actuation device 70 is disactivated, that is to say does not receive an electricity supply such as to generate a magnetic field sufficient to shift the engagement plate 42 (figure 3) .

[0055] In said configuration, the engagement device 40 is engaged with the rotor 10.

[0056] In particular, the plate 42 abuts with the engagement area 16a of the cap 16 of the rotor, thrust towards the rotor by the effect exercised by the elastic plate 50.

[0057] The rotor 10, the engagement plate 42 and the shaft 6 are therefore joined in rotation, so that the rotation of the shaft 6 imposed by the pulley 8, is accompanied by a corresponding rotation of the rotor 10.

[0058] In an inactive or non-functioning configuration, the actuation device 70 is activated, that is to say receives an electricity supply such as to generate a magnetic field sufficient to move the engagement plate 42 backwards (figure 4).

[0059] In said configuration, the engagement device 40 is disengaged from the rotor 10. In particular, the plate 42 is released from the engagement area 16a of the cap 16 of the rotor.

[0060] Consequently, the rotation of the shaft 6 does not drag the rotor in rotation.

[0061] The actuation device 70 is controlled by control means which, for example, electrically power the actuation device 70 so as to activate and disactivate itself in a desired time sequence, so as to adapt to the cooling requirements of the thermal motor.

[0062] Innovatively, the pump according to the present invention makes it possible to regulate the cooling of the motor according to the cooling requirements resulting from conditions of use with greatly reduced response times .

[0063] Advantageously, moreover, the pump shows itself to be considerably reliable, including as regards the engagement device, and is a small size.

[0064] This is due mainly to the fact that the coupling unit is housed in the main compartment of the pump and is therefore subject to reduced effort compared to the solutions with coupling units between the pulley and the shaft .

[0065] Advantageously, moreover, the pump manifests reduced inertia in the coupling phase compared to similar solutions of the prior art.

[0066] It is clear that a person skilled in the art may make modifications to the pump described above so as to satisfy contingent requirements all contained within the sphere of protection as defined by the appended claims.