EP3455499B1

EP3455499B1 - Pump group, with electric drive and mechanical drive, comprising a supported impeller

Info

Publication number: EP3455499B1
Application number: EP17721847.6A
Authority: EP
Inventors: Alfonso SURACE; Marco Pedersoli
Original assignee: Industrie Saleri Italo SpA
Current assignee: Industrie Saleri Italo SpA
Priority date: 2016-05-10
Filing date: 2017-03-30
Publication date: 2020-07-15
Anticipated expiration: 2037-03-30
Also published as: HUE050224T2; CN109154300B; ITUA20163303A1; WO2017195049A1; CN109154300A; EP3455499A1

Description

The present invention relates to a pump group for a cooling circuit of a vehicle, preferably for cooling an engine, such as an internal combustion engine.
As is known, during normal use of an engine, it is appropriate to vary the intensity of the cooling action.
For example, an intense cooling is appropriate when the engine is working at full capacity or in towing conditions or on an uphill road or with high ambient temperatures. In other conditions of use instead, it is appropriate for the cooling not to be accentuated, for example when starting the engine or after use.
The prior art discloses cooling pumps in which this need has been addressed.
Cooling pumps are in fact known of for electrically operated vehicles, in which the speed of rotation of the impeller is regulated by means of an electric drive and thus the amount of coolant liquid moved by it in circulation in the cooling circuit.
Electrically operated pumps are extremely versatile in their application and in the possibilities of rotation control thanks to the dedicated electronic control, presenting however low delivery power, limited by the electric power provided by the vehicle's electrical system. Furthermore, these pumps do not have the "fail-safe" feature in case of failure, i.e. the possibility to function in an emergency configuration when the electric engine has suffered a breakage.
Mechanically operated pumps are also known of where the rotation of the impeller is related to the number of revolutions of the internal combustion engine; in these solutions, the adjustment of the quantity of coolant liquid is entrusted to special adjustment elements, placed upstream or downstream of the impeller, suitable to change the through cross-section of the circuit thus varying the flow of coolant liquid.
Mechanical pumps are therefore suitable for delivering high power and prove conspicuously reliable but have less versatile cooling control, related to the engine speed and the characteristics of the adjustment element, and are typically too large. In addition, with the engine off, in a "post-run" configuration, no cooling is performed.
In addition, dual driven pumps are also known of, i.e. comprising both an electric drive and a mechanical drive.
Dual-drive pumps are therefore suitable to exploit the advantages of both types of drives, presenting however a particularly complex management of the two drives as well as a particularly articulated structure. An example of a known pump group is disclosed in document DE102014220377A1 .
The purpose of the present invention is to provide a pump group for a cooling circuit of a vehicle, for example for an internal combustion engine, which meets the requirements mentioned, over coming the drawbacks spoken of. In other words, the purpose of the present invention is to provide a dual drive pump group, with simplified management of the two drives and with a simple and compact structure.
Such purpose is achieved by a purrp group made according to claim 1. The dependent claims refer to preferred embodiment variants having further advantageous aspects.
The obj ect of the present invention will be described in detail below, with the help of the appended drawings, wherein:
- Figure 1 is a schematic cross-section view of a first embodiment of the purrp group of the present invention;
- Figure 2 shows a schematic cross-section view of a second embodiment of the pump group of the present invention;
- Figure 3 shows a schematic cross-section view of a third embodiment of the pump group of the present invention.
With reference to the aforementioned drawings, reference numeral 1 globally denotes a pump group for a cooling system of an engine, preferably an internal combustion engine.
The pump group 1 of the present invention comprises an impeller 2 rotatable around an axis X-X so that the rotation of the impeller 2 corresponds to the movement of a predetermined quantity of coolant liquid in the circuit.
Preferably, the impeller 2 is of the radial type, i.e. provides that the incoming flow of liquid has an overall substantially axial direction and the flow of liquid in out put has a radial direction.
The impeller 2 comprises a paddle portion 21 provided with a plurality of paddles, which moved in rotation are suitable to performan action on the cool ant liquid.
In addition, the impeller 2 comprises a support portion 22 which presents a support surface 220 to which a support and centering bearing 20 is operatively connected suitable to support the impeller 2 and keep it centred on the axis X-X, as amply described below.
The pump group 1 provides a dual drive, i.e. operable both mechanically and electrically. To such purpose, the pump group 1 comprises a mechanical drive 3 and an electric drive 5 both operatively connected, as fully described below, to the impeller 2 respectively by means of a first one-way coupling 61 and a second one-way coupling 62.
In a preferred embodiment, the pump group 1 comprises a mechanical shaft 300 rotatable by the mechanical drive 3 and operatively connected to the impeller 2.
In a preferred embodiment, the mechanical drive 3 comprises a pulley 33 for a drive belt connected, for example by using a kinematic chain, to the drive shaft. In a preferred embodiment, said pulley 33 is of the electromagnetic pulley type so that its activation i.e. its "grip" and its action on the impeller, and its deactivation, i.e. its release, is electrically controllable.
However, the present invention is not limited to a specific embodiment of the mechanical drive 3 or its control, as the scope of protection of the invention is solely defined by the appended claims.
Similarly, in some preferred embodiments, the pump group 1 comprises an electric shaft 500 rotatable by the electric drive 5 and, in turn, operatively connected to the impeller 2.
Preferably, the electric drive 5 comprises an electric engine 50 comprising a rotor 51 and a fixed stator 52 coaxial to the rotor 51. In a preferred embodiment, said rotor 51 is assembled on a rotor portion 501 of the electric shaft 500; in other embodiments, the rotor 51 is, as described below, directly mounted on a rotation body 8 connected to the impeller 2.
The pump unit 1 further comprises an electronic control unit 55 to control the electric drive 5 and/or electromagnetic pulley (if provided).
Similarly to the mechanical drive 3, the present invention is not limited to a specific embodiment of the electric drive 5 or its control, as the scope of protection of the invention is solely defined by the appended claims.
As mentioned, the drives are both operatively connected with the impeller 2 to control the rotation speed thereof; in the embodiments with the mechanical shaft 300 and electric shaft 500, these are both operatively connected with the impeller 2 to control the rotation speed thereof.
Preferably, the mechanical shaft 300 and electric shaft 500 extend along the axis X-X.
In a preferred embodiment, the mechanical shaft 300 and the electric shaft 500 extend in two opposite directions, on the two sides of the impeller 2, preferably, in such a way as to present the mechanical drive 3 rearwards of the impeller 2 and the electric drive 5 in front of the impeller 2.
In a further preferred embodiment, the mechanical shaft 300 and the electric shaft 500 extend in the same direction with respect to the impeller 2 one concentric with the other.
Preferably, both the mechanical drive 3 and the electric drive 4 are placed rearwards of the impeller 2; in further embodiments both the mechanical drive 3 and electric drive 4 are placed in front of the impeller 2.
The pump group 1 further comprises a rotation body 8 which extends along the axis X-X integrally connected to the impeller 2 to move it in rotation. Preferably, the electric drive 3 and the mechanical drive 5 are operatively connected to said rotation body 8 by means of the first one-way coupling 61 and the second one-way coupling 62.
The electric drive 300 and the mechanical drive 500 are operatively connected to said rotation body 8 to control its rotation by means of the first one-way coupling 61 and the second one-way coupling 62.
Preferably, the rotation body 8 is a rotation shaft. That is to say that the rotation body 8 extends in length along the axis X-X, preferably beyond the height of the impeller 2, for example, extending in front of the paddle portion 21 and/or rearwards of the support portion 22.
According to a further preferred embodiment, the rotation body 8 is a central hub. That is to say that the rotation body 8 extends in length along the axis X-X, but substantially by a stretch substantially equal to the height of the impeller 2.
Preferably, the first one-way coupling 61 and the second one-way coupling 62 are co-moulded in the rotation body 8.
Preferably, the rotation body 8 and the impeller 2 are in one piece. For example, the rotation body 8 and the impeller 2 are moulded together.
In a preferred embodiment, the rotation body 8 has a housing cavity 80 which extends along the axis X-X in which the first one-way coupling 61 and the second one-way coupling 62 are housed. In this embodiment, for example, the mechanical shaft impeller end 302 and the electric shaft impeller end 502 are housed in turn inside the rotation body 8.
Preferably, in a preferred embodiment, the mechanical shaft impeller end 302 comprises a pin 302' that extends along the axis X-X, while the electric shaft impeller end 502 comprises a housing 502' suitable to house and rotationally support the pin 302'.
Instead, in an embodiment variant (not shown) the electric shaft impeller end 502 comprises a pin which extends along the axis X-X, while the mechanical shaft impeller end 302 comprises a housing suitable to house and rotationally support the pin.
According to a preferred embodiment, said pin is housed in the respective housing comprising a bushing suitable to limit the friction between the two shafts.
According to a preferred embodiment, the pump group 1 comprises a pair of sealing elements 91, 92 operatively connected to the ends of the rotation body 8 to sealingly isolate the housing cavity 80 from the coolant liquid 120.
Preferably, the rotation body 8 has an impeller end 81 to which the impeller 2 is integrally fitted and a drive end 85 to which the first one-way coupling 61 and the second one-way coupling 62 are operatively connected. For example, the impeller end 81 houses internally the first one-way coupling 61 and externally the second one-way coupling 62 (as shown by way of example in Figure 2).
In other embodiments, as said, the drives act through the one-way couplings on the rotation body 8; the latter extending in length presenting a first operating portion 810 on which the first one-way coupling 61 is fitted and a second operating portion 820 on which the second one-way coupling 62 is fitted.
For example, in the embodiment with the mechanical shaft 300 and with the electric shaft 500, these comprise a mechanical shaft impeller end 302 and an electric shaft impeller end 502 operatively connected to the impeller 2 respectively by means of a first one-way coupling 61 and a second one-way coupling 62.
In other words, between the mechanical shaft 300 and the impeller 2 the first one-way coupling 61 is interposed, while between the electric drive 500 and impeller 2 a second one-way coupling 62 is placed.
According to a preferred embodiment, the first one-way coupling 61 comprises a rolling bearing for the support in rotation of the electric shaft 300 and/or rotation body 8. For example, the rolling bearing is of the type with rollers or needle rollers, having rolling elements placed between the driven ring and the drive ring.
According to a preferred embodiment, the second one-way coupling 62 comprises a rolling bearing for the support in rotation of the mechanical shaft 500 and/or rotation body 8. For example, the rolling bearing is of the type with rollers or needle rollers, having rolling elements placed between the driven ring and the drive ring.
According to the description above, in a preferred embodiment, the first one-way coupling 61 and the second one-way coupling 62 are arranged side by side along the axis X-X. In addition, in a further preferred embodiment, the first one-way coupling 61 and the second one-way coupling 62 are arranged with one concentric to the other. For example, in this embodiment, the first one-way coupling 61 and the second one-way coupling 62 are axially parallel to the axis X-X, superposed for at least a portion.
According to the invention, the support portion 22 of the impeller 2 extends axially along the axis X-X and is positioned rearwards of the paddle portion 21.
The support surface 220 is placed in a distal position from the axis X-X, preferably having a circular shape.
That is to say that in a preferred embodiment, the support surface 220 has the form of a ring.
Preferably, the support and centering bearing 20 is positioned inside the support surface 220, which is suitable to protect and shelter it.
In other embodiments, the support and centering bearing 20 is, instead, placed outside the support surface 220.
According to a preferred embodiment, the support and centering bearing 20 is a ball bearing.
Preferably, therefore, the support and centering bearing 20 is suitable to support the impeller 2, absorbing the action of the coolant liquid on it, and in particular on the paddle portion 21.
Preferably, in fact, the pump group 1 comprises a pump body 10 in which an impeller chamber 120 is defined in which the impeller 2, as well as the rotation body 8, and the support and centering bearing 20 are housed.
In this impeller chamber 120 the coolant liquid is therefore suitable to flow through a suction intake 121, towards an exit mouth 122 in thrust.
Preferably, therefore, the impeller chamber 120 is shaped to allow the housing of the impeller 2 and the correct flow of the coolant liquid inside it.
In a preferred embodiment moreover the impeller chamber 120 comprises a ring housing 125 in which the support surface 220 and the support and centering bearing 20 are housed.
Preferably, the ring housing 125 is positioned rearwards of the impeller 2 and is specially shaped to allow the housing inside it of the support surface 220 and the support bearing 20. In other words, the ring housing 125 has a shape substantially complementary to the space needed to contain the support surface 220 and inside it the support bearing 20.
According to a preferred embodiment, therefore the pair of sealing elements 91, 92 is suitable to sealingly isolate the housing cavity 80 to prevent the coolant liquid 120 in transit in the impeller cavity 120 from wetting the first one-way coupling 61 and the second one-way coupling 62.
Preferably, the pump group 1 is suitable to present all the advantages related to the dual drive.
For example, when starting the vehicle, if the engine is still cold (so-called "warm-up" configuration), the electromagnetic pulley is activated, in order to disengage the action on the mechanical shaft 300 while the electric drive 5 is left off. As a result the impeller 2 remains stationary, the liquid does not circulate in the circuit and the engine warms up faster.
According to another example, under heavy load conditions, such as when the vehicle is towing a trailer or going uphill, typically at low speed (for example at low engine revs), the electric drive 5 is activated in order to place the electric shaft 500 in rotation at a speed greater than that induced by the mechanical drive 3 and by the mechanical shaft 300, thus inducing the impeller 2 to rotate at the speed induced by the electric shaft 500.
Advantageously, in this configuration, the first one-way coupling 61 disengages in rotation the impeller 2 from the mechanical shaft 300 reducing the masses dragged in rotation by the electric drive 5.
According to a further example, after use of the vehicle, if the coolant liquid is still very hot, the electric drive 5 is activated so as to keep the impeller 2 rotating (this stage is called "post run"). This way, the impeller 2 rotates at a predetermined rotation speed, while the mechanical drive 3 is completely inactive, since the vehicle engine is off. Specifically, for example, the electromagnetic pulley is not energized, it not being necessary for the movement of the rotation shaft. In this case too, the first one-way coupling 61 disengages in rotation the impeller 2 from the mechanical shaft 300 reducing the masses dragged in rotation by the electric drive 4.
In general, therefore, the electric drive 5 is activable whenever it is necessary to increase the cooling capacity, regardless of the mechanical drive 3, related to the engine speed.
For example, in an embodiment in which the pump group 1 comprises a mechanical drive 3 which has a "classic pulley", of the mechanical type, therefore not controlled electronically, and the above described throttle valve, in the above-described "warm-up", phase in which the engine is still cold and heating as fast as possible is desired, the quantity of coolant liquid in circulation is regulated by controlling the positioning of further mechanical components placed downstream of the impeller chamber, for example a control valve.
Innovatively, the pump group according to the present invention satisfies the cooling requirements of the engine and overcomes the drawbacks referred to above.
Advantageously, the pump group according to the invention is very flexible, presenting all the advantages of dual type drives.
Moreover, advantageously, the pump group is particularly compact and small in dimensions, making it particularly suitable to be housed in the engine compartment of an engine vehicle.
A further advantageous aspect lies in the fact that the dual drive of the impeller is controlled by the presence of one-way couplings in a particularly simple and efficient manner, transmitting to the impeller the rotary action induced by the faster drive. In other words, advantageously, the transition from the electric drive to the mechanical drive and vice versa is operated mechanically by the one-way couplings. Therefore, advantageously, the electronic management of the pump group is very simple.
Advantageously, the design of the mechanical drive and the electric drive is extremely simplified and is optimisable by the engineer. For example, the electromagnetic pulley, if provided, does not require special design updates. In addition, the rotor of the electric engine is mounted directly on the electric shaft without the need for special screening bearings, thus limiting the axial dimensions of the rotor.
Advantageously, the pump group is able to avoid the cooling action, even though the engine is in gear, when, for example, in conditions of "warm-up", it is appropriate to heat the engine. In addition, the pump unit has the "fail safe" characteristic. Indeed, in the event of a failure of the electric drive the pump group, thanks to the mechanical drive and the second one-way coupling, continues to ensure the movement of the impeller.
In addition, according to a further advantageous aspect, the pump group is operative in "after-run" conditions, i.e. with the engine off. Advantageously, in conditions of "post-run", it is possible to avoid electrically powering the electromagnetic pulley saving electricity.
In addition, advantageously, the second one-way coupling, in a configuration in which the impeller is made to rotate by the mechanical drive, prevents the rotor from being dragged in rotation by the shaft; magnetic friction is thus not produced (nor does the rotor-stator group work as an electric generator).
Moreover, advantageously, the first one-way coupling and the second one-way coupling are selectable with different characteristics in function of the different actions required of the electric drive and the mechanical drive.
A further advantageous aspect lies in the fact that the impeller is supported and kept centred thanks to the presence of the centering and support bearing working directly on it.
According to further advantageous aspect, the one-way couplings are not affected by the action of the coolant liquid, which instead is absorbed by the centering and support bearing.
Advantageously, the self-centered and self-supported impeller does not require perfect alignment of the mechanical shaft and electric shaft, when present, nor is it necessary for these to support the rotation body and/or impeller through the couplings.
Advantageously, the rotation body and impeller have compact dimensions and are designable to exploit the presence of the centering and support bearing and the advantages it brings.
Advantageously, the pump group of the present invention is efficaciously applicable even coupled to next-generation engine groups, typically with engine boosting. These engine groups are suitable to deliver high power even at low revs, therefore having a mechanical drive of limited efficiency with consequent limited hydraulic performance of the impeller, recovered by the pump group of the present invention by the electric drive.
It is clear that a person skilled in the art may make modifications to the pump group described above so as to satisfy contingent requirements, all contained within the scope of protection as defined by the following claims.
In addition, each variant described as belonging to a possible embodiment may be realised independently of the other embodiments described.

Claims

Pump group (1) for a cooling circuit of the engine of a vehicle, comprising:
- an impeller (2) rotatable about an axis (X-X), comprising:
i) a paddle portion (21); and

ii) a support portion (22) extends axially along the axis (X-X) and is placed behind the paddle portion (21) having a support surface (220) placed in a distal position from the axis (X-X), preferably having a circular shape;

- a rotation body (8) which extends along the axis (X-X) integrally connected to the impeller (2) to move it in rotation, wherein the rotation body (8) is a rotation shaft or central hub;

- a mechanical drive (3) and an electric drive (5) comprising an electric engine (50);
wherein the mechanical drive (3) and the electric drive (5) are respectively operatively connected to said rotation body (8) by a first one-way coupling (61) and a second one-way coupling (62);
wherein the pump group (1) comprises a support and centering bearing (20) positioned on the support surface (220) to support and keep the impeller (2) centred on the axis (X-X).
Pump group (1) according to claim 1, wherein said support and centering bearing (20) is positioned inside the support surface (220).
Pump group (1) according to any of the preceding claims, wherein the support and centering bearing (20) is a ball bearing.
Pump group (1) according to any of the preceding claims, further comprising a pump body (10) in which an impeller chamber (120) is identified, housing the impeller (2) and supporting and centering bearing (20).
Pump group (1) according to claim 4, wherein the impeller chamber (120) comprises a ring housing (125) in which the support surface (220) and the support and centering bearing (20) are housed.
Pump group (1) according to anyone of the preceding claims, wherein the rotation body (8) and the impeller (2) are in one piece.
Pump group (1) according to anyone of the preceding claims, wherein the rotation body (8) has a housing cavity (80) along the axis (X-X) in which the first one-way coupling (61) and the second one-way coupling (62) are housed.
Pump group (1) according to claim 7, comprising a pair of sealing elements (91, 92) operatively connected to the ends of the rotation body (8) to sealingly isolate the housing cavity (80) from the coolant liquid (120).
Pump group (1) according to anyone of the preceding claims from 1 to 6, wherein the rotation body (8) has an impeller end (81) to which the impeller (2) is integrally fitted and a drive end (85) to which the first one-way coupling (61) and the second one-way coupling (62) are operatively connected.
Pump group (1) according to anyone of the preceding claims from 1 to 6, wherein the rotation body (8) extends in length by presenting a first operating portion (810) on which the first one-way coupling (61) is fitted and a second operating portion (820) on which the second one-way coupling (62) is fitted.
Pump group according to any of the preceding claims, comprising a mechanical shaft (300) rotatable by the mechanical drive (3) and an electric shaft (500) rotatable by the electric drive (5), in which the mechanical shaft (300) and the electric shaft (500) are operatively connected by means of respective one-way couplings to the rotation body (8).
Pump group (1) according to any of the preceding claims, wherein the electric drive (3) and the mechanical drive (5) extend on opposite sides of the impeller (2), preferably so that the mechanical drive (3) is placed behind the impeller (2) while the electric drive (5) is in front of the impeller (2).
Pump group according to any of the claims from 1 to 11, wherein the electric drive (5) and the mechanical drive (3) extend on the same side of the impeller (2) so that the mechanical shaft (300) and the electric shaft (500) extend concentrically to each other.