Operating assembly of pump for recirculating cooling fluid of combustion engine and recirculating pump provided with such operating assembly

Abstract

Operating assembly for a pump for recirculating a cooling fluid of a vehicle, comprising: an axially extending driven shaft (2), the front end (2a) of which is designed to carry an impeller (1) of the pump; at least one electromagnetic friction clutch (2) arranged between a motion receiving element (223, 202) for receiving a rotational motion and the output shaft (2); an electric drive for driving the driven shaft (2) independently of the motion receiving element; a support body (11, 113) extending axially between a front portion of the front end of the carrier shaft (2) and a rear foot supporting the motion-receiving element.

Description

[0001] The present invention relates to an operating assembly of a pump for recirculating the cooling fluid of a combustion engine (especially a combustion engine of a vehicle), the operating assembly having an operating device, the operating device comprising an electromagnetic clutch and an electric drive, the electric drive being independent of the combustion engine, and the present invention also relates to a recirculation pump provided with the operating assembly.

[0002] It is known in the field of production of engines, in particular combustion engines, to cool said engines by recirculation of a cooling fluid driven by a corresponding recirculation pump, the impeller of which is driven in rotation by a shaft operated by a pulley and a belt connected to the drive shaft.

[0003] It is also known that the recirculation of the cooling fluid must be carried out with a flow rate corresponding to the actual cooling requirement determined by the actual conditions of use of the engine and the external temperature, in order to avoid constant and unnecessary operation of the device at full speed, extracting useful power and therefore increasing the wear of the various component parts and the consumption level of the vehicle.

[0004] It is also known that in order to solve this problem, a hybrid device for controlling the operation of the pump impeller shaft has been proposed, the rotation of which depends on the engagement of a friction coupling for transmitting a rotational movement depending on the number of revolutions of the drive shaft and an electric motor, which is driven when the friction coupling is disengaged, for rotating the impeller at a controlled speed independently of the drive shaft.

[0005] Despite performing their functions, these devices still have drawbacks that limit their application, in particular because the known constructions have axial dimensions that are incompatible with the free volume available in the engine compartment, especially with regard to the limited amount of axial space available between the pump and the fan (which pushes air onto the cooling liquid contained in the front radiator), these requiring corresponding drive belts for connection to the combustion engine in order to receive the rotational movement.

[0006] The technical problem posed is therefore to provide an operating assembly for a pump for recirculating cooling fluid of an engine of a vehicle or the like, which operating assembly is able to generate a variation of the rotational speed of the pump impeller according to the actual operating requirements of the engine.

[0007] In relation to this problem, it is also required that the configuration of the operating assembly should be designed to ensure that the overall size of the pump equipped with the assembly is such that the distance from the vehicle fan in the axial direction can avoid destructive interference therebetween.

[0008] A further object is that the pump operating assembly should be able to output high torque also at low engine rotation speeds, so as to be suitable also for high capacity pumps of heavy vehicles with low engine speeds, or when the impeller rotates at low speeds when the combustion engine is running at high speeds.

[0009] It is also desirable that the device be easy and cheap to produce and assemble and be able to be easily mounted on the pump body without the need for special adaptations.

[0010] These results are obtained according to the invention by an operating assembly of a pump for recirculating cooling fluid of an engine of a vehicle or the like according to the features of claim 1 .

[0011] The invention also relates to a pump for recirculating cooling fluid of an engine of a vehicle or the like, the pump being equipped with such an operating assembly.

[0012] Further details can be gathered from the following description of non-limiting examples of embodiments of the subject matter of the invention, provided with reference to the accompanying drawings, in which:

[0013] Figure 1 is a cross-sectional view of a first example of an embodiment of an operating assembly for a pump according to the present invention;

[0014] Figure 2 is an overall cutaway view of the pump operating assembly with the adjacent cooling fan installed.

[0015] like Figure 1 As shown, the operating assembly comprises a shaft 2 on the front end 2a of which is mounted an impeller 1 of a pump for recirculating the vehicle's cooling fluid. The shaft 2 is supported by a fixed support body 10 which in turn is fixed to a base 4 of the vehicle's engine.

[0016] The supporting body of the pump operating assembly comprises a first body part 11 close to the impeller, which first body part 11 supports the front end 2a of the shaft 2.

[0017] The first body component 11 is fixed on the base 4 and has a sealing gasket (the sealing gasket is coaxial with the shaft 2 ) and a bearing 15 arranged inside it. The shaft 2 of the impeller is keyed to the inner ring of the bearing 15 .

[0018] The first pump body part 11 has a front end of a second fixed body part fixed thereto, formed by a bell-shaped part 113, which is shown as a Z-shape in the cross-sectional view and includes: a front radially outer axial arm 113a, a radial arm 113b extending from the axial arm toward the rotation axis of the shaft 2, and an axial support foot 113c extending from the radial arm and axially away from the impeller 1.

[0019] In the preferred embodiment shown, the clutch 220 comprises:

[0020] - a fixed electromagnet 222 integral with the bell-shaped part 113 on its radial arm 113 b;

[0021] - a mechanical rotor 221, which preferably has an L-shaped cross-sectional form;

[0022] An armature 225 arranged facing the electromagnet 222 with the front face of the rotor 221 arranged between the electromagnet 222 and the armature 225 itself.

[0023] The mechanical rotor 221 is integral with an auxiliary spindle 202 keyed to the inner ring of a bearing 224, the outer ring of which has the foot 113c of the bell 113 keyed thereto, which thus supports the spindle 202 with the possibility of relative rotation.

[0024] The impeller shaft 2 and the auxiliary spindle 202 are preferably coaxial and independent.

[0025] The pulley 223a is rigidly connected to the rear end of the spindle 202 carried by the foot 113c. The pulley 223a is suitable for coupling with a belt 3 connected to the driving shaft or driven shaft of the combustion engine, thus forming an element for receiving the rotational movement transmitted, for example, from the shaft of the combustion engine, for the rotational operation of the spindle 202 and therefore of the mechanical rotor 221.

[0026] according to Figure 1 In the preferred embodiment of the present invention, the pulley 223a is formed on the outer surface of the motion receiving flange 223 fixed to the rear end of the spindle 202. The flange 223 has a radially outer axial arm, and the pulley 223a is formed on the radially outer axial arm. The front end of the axial arm is free, while the rear end is connected to the radial arm 223b, which is connected to the spindle 202 through the radial inner leg.

[0027] The flange 223 defines an internal volume 223c between the outer axial arm and the inner foot, and the rear foot 113c of the pump body 10 is preferably at least partially accommodated within the internal volume 223c, thereby reducing the axial size of the pump unit.

[0028] The armature 225 supports an elastic plate 226 on its face opposite to the electromagnet 222, and the elastic plate 226 is fixed on a flange 233, which is in turn integral with the end 2b of the shaft 2 opposite to the end of the impeller 1; therefore, the armature 225 rotates integrally with the flange 233.

[0029] Through this coupling, the armature 225 can perform movement in the axial direction toward / away from the mechanical rotor 221, so that when the electromagnet 222 is energized, the armature 225 and the flange 226a are rotationally coupled with the rotor 221, but when the electromagnet 222 is de-energized, the armature 225 and the flange 226a are stationary in an idling state.

[0030] like Figure 1As shown, it is also envisaged that the electric drive, in particular the electric motor 30 , is arranged inside the bell-shaped member 113 , in an axial position between the impeller 1 of the pump and the electromagnetic clutch 220 .

[0031] In more detail, the electric motor 30 comprises a stator 31 fixedly mounted on the supporting body 11 and an electric rotor 32 mounted on a first axial extension 233a of the flange 233 designed to place the rotor in a radially outer position concentric with the stator for radial connection therewith.

[0032] A second axial extension 233 b of the rotor flange 233 , opposite to the aforementioned flange, is integral with the shaft 2 of the impeller 1 .

[0033] Therefore, the operating assembly according to the invention preferably has an arrangement which comprises, in sequence along the axial extension of the assembly: the impeller 1, the electric motor 30, the flange 233 of the electric rotor, the armature 225, the mechanical rotor 221, the electromagnet 222 and the motion receiving element 223. The electric rotor 32 and the armature 225 are coupled in rotation with the shaft 2 of the impeller, while the mechanical rotor 221 and the motion receiving element 223 are coupled in rotation with the auxiliary spindle 202.

[0034] Due to the structural form of the support body (which is preferably made in two parts 11, 113, with a bell-shaped part 113 which accommodates the electric motor 30 and supports the bearing 224, the auxiliary spindle 202, the motion receiving flange 223 and the mechanical rotor 222 at the rear end), the diameter of the motion receiving pulley 223a can be freely determined and therefore has no size restrictions (for example due to the magnetic circuit of the clutch rotor). Therefore, the desired speed multiplication / reduction ratio can be easily set with respect to the pulley and the belt of the combustion engine,

[0035] Moreover, due to the arrangement of the present invention, the production and assembly process can also be significantly simplified, saving costs and materials.

[0036] Figure 2 It is shown how it is possible, through the novel structure of the pump operating assembly, to arrange a motion receiving element 223a, suitable for coupling with the auxiliary belt 3 driving the pump impeller, in an axially external position at the rear end of the operating assembly, opposite the impeller, resulting in an axial length of the entire assembly that leaves sufficient space between the assembly itself and the fan V for cooling the fluid in the front radiator, without interference. Moreover, this avoids interference with the main belt CP for driving the fan, which is arranged in an axial position between the belt 3 of the pump and the impeller 1.

[0037] In addition, it should be noted that the tension of the belt 3 is released to the rear bearing 224 carried by the extension 113c of the bell-shaped part 113 fixed to the body 11, which makes it possible to limit the size of the internal bearing 15, which is housed in the first part of the body 11 and is not subject to the dynamic radial loads of the belt 3, but only has to bear the mass of the impeller and the electric rotor 32, the armature 225 and the relative flange 233. The operating life of the transmission is thus increased and the overall dimensions are limited.

[0038] Moreover, due to the operating structure of the present invention, the radial dimensions of the pump unit can also be advantageously kept compact.

[0039] With these constructions, the pump works as follows:

[0040] -) When the electromagnet 222 is energized, the induced magnetic field overcomes the elastic resistance of the plate 226, thereby causing the armature 225 to retract axially, thereby engaging it with the mechanical rotor 221, which moves through the auxiliary spindle 202 via the pulley 223a; this engagement causes the flange 223 to rotate, thus causing the shaft 2 of the impeller 1 to operate at a speed determined by the combustion engine through the belt 3 and the pulley 223a;

[0041] -) when the electromagnet 222 is de-energized, the armature 225 is retracted axially away from the electromagnet 222 by means of the elastic plate 226, thereby separating the mechanical rotor 221 from the flange 223 and thus from the shaft 2 holding the impeller in idle rotation;

[0042] -) When, in the idling state of shaft 2, impeller 1 needs to rotate at a speed independent of the speed determined by the combustion engine, electric motor 30 is powered so that the movement of its rotor 32 causes shaft 2 to rotate at the desired rotational speed actually required, suitable for determining fluid recirculation.

[0043] It should be clear how the operating assembly for the recirculation pump according to the invention is able to ensure an efficient drive of the pump impeller, wherein the recirculation of the vehicle cooling fluid can be varied according to actual needs by alternately driving the combustion engine or the auxiliary electric motor, but at the same time maintaining small radial dimensions, which allows to obtain a pulley also with a compact diameter, thus multiplying the number of revolutions transmitted by the belt 3, making the device and therefore the pump also suitable for vehicles with an engine running at a low number of revolutions but requiring a high-speed rotating cooling pump.

[0044] Furthermore, the size of the pulley is not dependent on the size of the outer diameter of the electric motor.

[0045] Although described in connection with an application to a water recirculation pump, it will be appreciated that the cooling fluid may also be oil and the operating assembly according to the invention may therefore be used with an oil pump.

Claims

1. An operating assembly for operating a pump for recirculating a cooling fluid of a vehicle, the operating assembly comprising: A driven shaft (2) extending axially with a front end (2a) designed to carry an impeller (1) of the pump; An electromagnetic friction clutch (220) arranged between a motion receiving element (223, 223a) for receiving rotational motion and a driven shaft (2); an electric drive (30) for driving the driven shaft (2) independently of the motion receiving element; - a support body (11, 113) extending axially between a front portion carrying the front end of the driven shaft (2) and a rear end rotatably supporting the motion receiving element; The electric drive (30) and the electromagnetic friction clutch (220) are axially arranged between the front end (2a) of the driven shaft and the motion receiving element (223, 223a).

2. The operating assembly according to claim 1, wherein: The supporting body is constructed of two parts and includes a first front body part (11) and a bell-shaped part (113), wherein the first body part supports the front end (2a) of the driven shaft (2) and is designed to be fixed on a fixed base (4), and the bell-shaped part is fixed on the first body part (11) and includes a rear support foot (113c) extending axially radially inwardly, wherein the rear support foot forms the rear end designed to support a motion receiving element (223, 223a) for receiving motion.

3. The operating assembly according to claim 2, wherein: The first bearing (15) is arranged between the driven shaft (2) and the first body part (11) of the support body.

4. An operating assembly according to any one of claims 2 and 3, wherein: The bell-shaped component (113) comprises: a front radially outer axial arm (113a), which is fixed to the first body component (11) of the supporting body; a radial arm (113b), which extends from the axial arm toward the rotation axis of the driven shaft (2); and a rear support leg (113c), which extends axially from the radial arm away from the impeller (1).

5. An operating assembly according to any preceding claim, wherein: The electromagnetic friction clutch (20) comprises: - a fixed electromagnet (22) which is integrally connected to the support body, in particular to the bell-shaped part (113); - a mechanical rotor (221), said mechanical rotor preferably having an L-shaped cross section; An armature (225) is arranged facing the electromagnet (222), wherein the radial front surface of the mechanical rotor (221) is arranged between the electromagnet (222) and the armature (225).

6. An operating assembly according to any preceding claim, further comprising: An auxiliary spindle (202) is keyed to the inner ring of a rear bearing (224), the rear bearing being mounted on the rear end of the support body, in particular, the rear bearing being mounted on a rear support foot (113c), wherein a motion receiving element (223, 223a) rotates integrally with the auxiliary spindle (202).

7. An operating assembly according to claims 5 and 6, wherein: The mechanical rotor (221) of the electromagnetic friction clutch is supported by the auxiliary spindle (202) and rotates integrally with the auxiliary spindle.

8. An operating assembly according to any one of claims 6 and 7, wherein: The auxiliary spindle is coaxial with the driven shaft (2) supporting the impeller.

9. An operating assembly according to any preceding claim, further comprising: A rotor flange (233) rotates integrally with a rear end (2b) of the driven shaft (2) opposite to the end supporting the impeller (1).

10. An operating assembly according to any preceding claim, wherein: The electric drive comprises: a radially inner stator (31), which is supported by a supporting body (11); and a radially outer rotor (32), which is mounted on a rotor flange (233), which rotates integrally with the driven shaft (2) and is configured to arrange the radially outer rotor at a radially outer position concentric with the radially inner stator for radial connection with the radially inner stator.

11. An operating assembly according to any one of claims 9 and 10 as appended to claim 5, wherein: The armature (225) of the electromagnetic friction clutch is rotationally coupled to the rotor flange (233) and can be axially displaced by an elastic plate (226) to couple or separate the rear end surface of the armature and the radial front surface of the mechanical rotor (221).

12. An operating assembly according to any one of claims 4 to 11, wherein: The rotor flange (233) is arranged axially between the front electric drive and the armature (225) of the electromagnetic friction clutch.

13. An operating assembly according to any one of claims 2 to 10, wherein: The bell-shaped component (113) of the supporting body extends a certain length in the axial direction so as to contain an electromagnetic friction clutch (220) and an electric drive (30) inside the bell-shaped component.

14. An operating assembly according to any preceding claim, wherein: The motion receiving element includes a motion receiving flange (223), which is fixed on the rear end of the auxiliary spindle (202), and the motion receiving flange (223) has a radial outer axial arm and a radial arm (223b), the outer surface of the radial outer axial arm forms a motion receiving pulley (223a), and the radial arm is connected to the spindle (202).

15. An operating assembly according to the preceding claim, wherein: The movement receiving flange defines an internal volume (223c) between the radially outer axial arm and the auxiliary spindle, and the rear leg (113c) of the support body (10) is at least partially accommodated in the internal volume.

16. An operating assembly according to any one of the preceding claims, characterized in that The structure comprises, in sequence along the axial direction of the rotation axis of the driven shaft (2), the front end supporting the impeller (1), an electric motor (30), a rotor flange (233) carrying the electric rotor, an armature (225) of an electromagnetic friction clutch, a mechanical rotor (221) of the electromagnetic friction clutch, an electromagnet (222) and the motion receiving element (223).

17. An operating assembly according to the preceding claim, wherein: The electric rotor (33) and the armature (225) are rotationally coupled to the driven shaft (2) of the impeller, and the mechanical rotor (221) and the motion receiving element (223) are rotationally coupled to an auxiliary spindle (202) which is separate from the driven shaft (2) supporting the impeller.

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