WO2022090829A1

WO2022090829A1 - Pump group

Info

Publication number: WO2022090829A1
Application number: PCT/IB2021/058797
Authority: WO
Inventors: Alfonso SURACE; Danilo MUSCIO; Luca DALLERA
Original assignee: Industrie Saleri Italo S.P.A.
Priority date: 2020-10-26
Filing date: 2021-09-27
Publication date: 2022-05-05
Also published as: CN116583676A; EP4232716A1; IT202000025315A1

Abstract

The invention is a pump group (1) fluidically connectable to a cooling system for an operating group, such as, for example, an internal combustion engine, an electric motor or a battery group of a vehicle. The pump group (1) comprises an impeller (2) and a shaft (3) on which the impeller (2) is integrally mounted. The pump group (1) has at least one drive of the electric type, in fact comprising an electric motor (4) comprising a rotor (41) integrally mounted on the shaft (3) and a stator (42). Furthermore, the pump group (1) comprises a pump body (6) comprising: - a first casing (61) which houses the impeller (2) in an impeller chamber (610); - a second casing (62) in which the electric motor (4) is housed in a motor chamber (620), wherein the second casing (62) comprises an intermediate tubular wall (625) positioned between the rotor (41) and the stator (42) so that a rotor chamber (621) and a stator chamber (622) are defined in the motor chamber (620), mutually tightly separated; Specifically, the first casing (61) and the second casing (62) are separated by a first separation wall (624) comprising an impeller surface (628) facing into the impeller chamber (610) and a motor surface (629) facing into the motor chamber (620). Even more specifically, the pump group (1) comprises a thermally conductive resin that at least partially covers the motor surface (629), to cool the stator chamber (622) by conduction.

Description

PUMP GROUP

DESCRIPTION

[0001] The present invention relates to a pump group for a vehicle cooling system.

[0002] In the course of the description, the term "vehicle" means any means of locomotion that comprises an internal combustion engine and also hybrid powered vehicles, without any limitation related to type or size, i.e. a motor vehicle or an articulated vehicle.

[0003] In other words, the present invention relates to the automotive sector and in detail to the thermal management system of a vehicle.

[0004] In particular, said cooling system is specific for cooling an "operating group" of the vehicle.

[0005] In particular, in the present description, "operating group" means a component or a group of components specific for the execution of a specific operation necessary for the motion of the vehicle. In a preferred embodiment, the "operating group" comprises the engine group, for example of the endothermic or electric type .

[0006] In further embodiments, the "operating group" comprises other components of the vehicle, both of the mechanical type, such as a transmission assembly, and of the electrical type, such as a "battery assembly" included in the vehicle.

[0007] In the prior art, many embodiments of pump groups for a cooling system of an operating group are known, which differ from each other in terms of size and type of actuation .

[0008] Specifically, the pump group object of the present invention falls within this context, having an electric-type drive. In other words, the pump group object of the present invention comprises at least one electric motor which controls the rotary movement of the impeller included therein, thus controlling the movement of the coolant liquid that flows in the cooling system to which the pump group is fluidically connectable.

[0009] A plurality of technical solutions of pump groups are known comprising an electric drive in which the main problem of this type of pump groups has been faced, i.e. the need to effectively cool the electric motor of the pump group and its related components.

[00010] In particular, embodiments of pump groups are known in which the coolant liquid present in the chamber where the impeller is housed is used to also cool the electric motor and its related components. Even more specifically, the interest in exploiting the coolant liquid for cooling the rotor included therein is known in the prior art. [00011] Furthermore, embodiments of pump groups are known in which the problem linked to the cooling of the stator is also addressed.

[00012] In some embodiments, the pump groups have been designed to favor the cooling of the stator towards the external environment.

[00013] In other embodiments, however, a certain quantity of oil has been provided in the stator chamber with the aim of cooling the chamber in which it is housed by convection. An example showing this pump group solution is for example shown in document W02020/07562 in the name of the Applicant.

[00014] On the other hand, these embodiments have an effective cooling of the rotor and/or of the stator, but fail to effectively cool the other portions of the pump group .

[00015] The object of the present invention is therefore to provide a pump group for a cooling system for an operating group of a vehicle that has an effective cooling of the entire electronic control components, obviating the problems mentioned above.

[00016] Such object is achieved by a pump group according to claim 1. The dependent claims relate to preferred embodiment variants having further advantageous aspects.

[00017] The object of the present invention is described in detail hereafter, with the aid of the accompanying drawings , in which :

[ 00018 ] - Figure 1 illustrates a longitudinal sectional view of a pump group according to the present invention, according to a first possible embodiment , in which a thermally conductive resin film on an motor surface is shown;

[ 00019 ] - Figure 2 illustrates a longitudinal sectional view of a pump group according to the present invention, according to a second possible embodiment , in which a thermally conductive resin film on an motor surface and a resin film/ layer on a tubular stator surface are shown;

[ 00020 ] - Figure 3 illustrates a longitudinal sectional view of a pump group according to the present invention, according to a third possible embodiment , in which a thermally conductive resin film on an motor surface , a resin film/ layer on a tubular stator surface , a resin film on a second separation wall are shown ;

[ 00021 ] - Figure 4 illustrates a longitudinal sectional view of a pump group according to the present invention, according to a fourth possible embodiment , in which a quantity of thermally conductive resin f ills a stator chamber and a command chamber ;

[ 00022 ] - Figure 5 illustrates a longitudinal sectional view of a pump group according to the present invention, according to a fifth possible embodiment, in which a thermally conductive resin layer on an motor surface is shown;

[00023] - Figure 6 illustrates a longitudinal sectional view of a pump group according to the present invention, according to a sixth possible embodiment, in which a quantity of thermally conductive resin and convention oil fill a stator chamber and a command chamber;

[00024] - Figure 7 shows an enlarged view of a portion of a pump group shown in Figure 1.

[00025] In the above tables, the reference numeral 1 denotes, in its entirety, a pump group for a cooling system for an operating group of a vehicle, preferably for cooling the engine group, for example of the internal combustion type .

[00026] The pump group 1 object of the present invention extends mainly in length with respect to an axis X-X.

[00027] The pump group 1 object of the present invention comprises an impeller 2 rotatable with respect to said axis X-X. In other words, said impeller 2 has a center of rotation which lies on said axis X-X.

[00028] Preferably, the impeller 2 is of the radial type being specially shaped to perform a suction action of the coolant liquid preferably in the axial direction and to perform a thrusting action preferably in the radial direction . In particular, the "coolant liquid" is a waterbased liquid, for example a solution comprising water and glycol , which circulates in the cooling system of the vehicle to which the pump group 1 obj ect of the present invention is fluidically connectable .

[ 00029 ] According to the present invention, moreover , the pump group 1 comprises a shaft 3 that extends in length along the axis X-X . Preferably, said shaft 3 comprises a rotating end 32 on which the impeller 2 is integrally mounted .

[ 00030 ] According to the present invention, the pump group 1 comprises an electric motor 4 suitable for driving the shaft 3 in rotation .

[ 00031 ] The electric motor 4 comprises a rotor 41 and a stator 42 . According to a preferred embodiment , the rotor 41 and the stator 42 are arranged concentrically with respect to the axi s X-X .

[ 00032 ] According to the present invention, the rotor 41 is integrally mounted, for example keyed, on said shaft 3 : the rotation of the shaft 3 and in turn of the impeller 2 corresponds to the electronically controlled rotation of the rotor 41 . The stator 42 axially and circumferentially surrounds the rotor 41 . In particular, the stator 42 comprises a plural ity of stator coils forming a stator .

[ 00033 ] According to the present invention, the pump group 1 comprises a pump body 6 which extends paral lel and mainly around the axis X-X . The pump body 6 is suitable for containing the various operating components of the pump group 1 and is suitable for being fluidically connectable to the vehicle cooling system .

[ 00034 ] According to the present invention, the pump body 6 comprises along the axis X-X :

- a first casing 61 which houses the impeller 2 in an impeller chamber 610 ;

- a second casing 62 in which the electric motor 4 is housed in a motor chamber 620 ; in particular, the motor chamber 620 houses the rotor 41 and the stator 42 .

[ 00035 ] According to the present invention, the second casing 62 comprises an intermediate tubular wall 625 which extends parallel to the axis X-X positioned between the rotor 41 and the stator 42 .

[ 00036 ] Said intermediate tubular wall 625 divides a rotor chamber 621 and a stator chamber 622 in the second casing 62 . In other words , the motor chamber 620 is divided into a rotor chamber 621 and a stator chamber 622 . Preferably, the rotor chamber 621 and the stator chamber 622 are mutually tightly separated .

[ 00037 ] According to a preferred embodiment , said first casing 61 , and in particular the impeller chamber 610 included therein, is fluidically connected with the ducts of the cooling system in which the cooling liquid flows.

[00038] According to the present invention, the first casing 61 and the second casing 62 are separated by a first separation wall 624. Said first separation wall 624 axially defines and tightly seals the motor chamber 620.

[00039] Specifically, according to the invention, said first separation wall 624 comprises an impeller surface 628 facing axially to the impeller 2, and comprises a motor surface 629 facing axially to the electric motor 4. In other words, the impeller surface 628 axially delimits the impeller chamber 610, while the motor surface 629 axially delimits the motor chamber 620.

[00040] Preferably, said first separation wall 624 is comprised in the first casing 61.

[00041] In an alternative embodiment, the first separation wall 624 is comprised in the second casing 62. [00042] In a further embodiment, the first separation wall 624 consists of a portion comprised in the first casing 61 and a portion comprised in the second casing 62. [00043] Preferably, the first separation wall 624 is traversed by and supports the shaft 3.

[00044] According to a preferred embodiment, the first separation wall 624 comprises at least one cooling hole 624' suitable for putting the rotor chamber 621 in fluid communication with the impeller chamber 610 in such a way as to allow the coolant liquid to flow also in said impeller chamber 610. In other words, the cooling hole 624' passes through the first separation wall 624.

[00045] According to a preferred embodiment, the shaft 3 comprises an axial hole 300 which extends mainly along the axis X-X.

[00046] Preferably, the coolant liquid flows inside said axial hole 300. Preferably, the axial hole 300 is through along the shaft 3.

[00047] According to a preferred embodiment, the pump group 6 comprises a third casing 63, in which an electronic command board 5 is housed in a command chamber 630.

[00048] According to a preferred embodiment variant, the third casing 63 and the second casing 62 delimit an auxiliary cooling chamber 631 fluidically connected to the rotor chamber 621, in such a way that said auxiliary cooling chamber 631 is also fluidically reached by the coolant liquid.

[00049] Specifically, according to a preferred embodiment, the second separation wall 623 comprises a central portion 6231 facing the command board 5 in a region proximal to the auxiliary cooling chamber 631.

[00050] According to a preferred embodiment, the second casing 62 and the third casing 63 are separated by a second separation wall 623. [00051] In other words, the command chamber 630 and the stator chamber 622 are separated by a second separation wall 623. Said second separation wall 623, together with the first separation wall 624, axially defines and tightly seals the motor chamber 620.

[00052] In a first preferred embodiment, the second separation wall 623 is comprised in the second casing 62. [00053] In a second preferred embodiment, the second separation wall 623 is comprised in the third casing 61.

[00054] In a further embodiment, the second separation wall 623 consists of a portion comprised in the second casing 62 and a portion comprised in the third casing 63. [00055] According to a preferred embodiment, said second separation wall 623 comprises at least one fluid passage suitable for fluidically connecting the stator chamber 622 and the command chamber 630.

[00056] In a preferred embodiment, the second casing 62 comprises an annular side wall 627 which extends parallel to the axis X-X. In addition, said side wall 627 radially defines the motor chamber 620, preferably the stator chamber 622.

[00057] Preferably, the side wall 627 tightly engages the first separation wall 624 and the second separation wall 623.

[00058] As already mentioned, the second casing 62 comprises an intermediate tubular wall 625 which extends parallel to the axis X-X positioned between the rotor 41 and the stator 42 dividing the motor chamber 620 into a rotor chamber 621 and a stator chamber 622.

[00059] According to a preferred embodiment, the intermediate tubular wall 625 comprises a stator tubular surface 626, facing radially the stator 42 and comprises a rotor tubular surface 626' radially facing the rotor 41. [00060] According to a preferred embodiment, the intermediate tubular wall 625 extends comprising along the axis X-X a first end 625' proximal to the first casing 61, preferably tightly engaging the first separation wall 624, preferably the motor surface 629, and comprises a second opposite end 625' ’ . Preferably, said second end 625' ’ engages the bottom of the second casing 62. Preferably, said second end 625' ’ is proximal to the third casing 62, tightly sealing the second separation wall 623.

[00061] According to a preferred embodiment, therefore, the intermediate tubular wall 625, in particular its first end 625' , divides the motor surface 629 into at least two distinct surfaces. Specifically, the intermediate tubular wall 625 divides the first separation wall 624, and in particular the motor surface 629, into a rotor portion

6291 axially facing the rotor 41, and a stator portion

6292 axially facing the stator 42. [00062] In other words, the motor surface 629 comprises said rotor portion 6291 and said stator portion 6292.

[00063] According to the present invention, the pump group 1 comprises a thermally conductive resin.

[00064] Preferably, for example, said thermally conductive resin is an epoxy thermally conductive resin.

[00065] Preferably, for example, said thermally conductive resin is a two-component, for example it is made of polydimethylsiloxane.

[00066] Specifically, the thermally conductive resin has a high thermal conductivity and, therefore, is suitable for creating a preferential thermal vector in the pump body 6. In other words, the positioning of thermally conductive resin facilitates cooling by conduction of the electric motor 4.

[00067] According to the present invention, said thermally conductive resin at least partially covers the motor surface 629, comprised in the first separation wall 624, in such a way as to cool the stator chamber 622 by conduction .

[00068] In particular, in fact, the first separation wall 624, in particular the impeller surface 628, is wetted and cooled by the coolant liquid. At the same time, the first separation wall 624 also comprises the stator portion

6292 facing the stator chamber 629. Therefore, the heat produced by the stator 62 heats said stator portion 6292 . [ 00069 ] In accordance with the above , between the impeller surface 628 and the stator portion 6292 there is a temperature gradient and the thermally conductive resin creates a preferential thermal vector that influences the temperature gradient , in such a way as to direct it .

[ 00070 ] In other words , the heat developed by the stator 62 and present in the stator chamber 620 is the obj ect of the thermal vector reali zed by the thermally conductive resin, and is therefore transmitted by conduction through the first separation wall 624 , from the stator chamber 620 to the impeller chamber 610 .

[ 00071 ] According to a preferred embodiment , the thermally conductive resin at least partially covers the stator tubular surface 626 in such a way as to cool the stator chamber 620 by conduction .

[ 00072 ] Speci fically, on the intermediate tubular wall 625 there is a temperature gradient between the stator tubular surface 626 , heated by the heat present in the stator chamber 622 , and the rotor tubular surface 626 ' , cooled by the coolant liquid flowing in the rotor chamber 621 . The heat transmission occurs by conduction through the intermediate tubular wall 625 from the stator chamber 622 to the rotor chamber 621 and the presence of the thermally conductive resin facilitates such heat exchange . [00073] According to a further preferred embodiment, the thermally conductive resin at least partially covers the second separation wall 623 in such a way as to cool the command chamber 630 by conduction.

[00074] In a preferred embodiment, the electronic command board 5 is housed in the command chamber 630 in a region proximal to the second separation wall 624.

[00075] In a preferred embodiment variant, the electronic command board 5 is anchored, for example screwed or glued, to the second separation wall 623.

[00076] In a preferred embodiment, the thermally conductive resin is placed between the second separation wall 623 and the electronic command board 5.

[00077] In this way, the transmission by conduction of the heat present in the command chamber 630 through the second separation wall 623 is optimized. In other words, the electronic command board 5 is cooled more effectively, by virtue of the presence of the thermally conductive resin which covers said second separation wall 623.

[00078] In a preferred embodiment variant, the electronic command board 5 is anchored, for example screwed or glued, to the second separation wall 623 and the thermally conductive resin is also placed around said electronic command board 5.

[00079] According to a preferred embodiment, the thermally conductive resin at least partially covers the central portion 6231 which faces the command chamber 630, in such a way as to cool the command chamber 630 by convection .

[00080] Specifically, at this point there is a temperature gradient between the central portion 6231, heated by the heat produced by the electronic command board 5, and the auxiliary cooling chamber 631, cooled by the coolant liquid.

[00081] In other words, the electronic command board 5 is cooled more effectively, to a still further extent.

[00082] According to a preferred embodiment, in the aforementioned embodiments, the thermally conductive resin positioned on the aforementioned walls in the form of a film.

[00083] In other words, the thermally conductive resin is positioned with a minimum thickness on the concerned walls .

[00084] In other embodiments, the thermally conductive resin is positioned on the aforementioned walls and surfaces in the form of a layer. Unlike the aforesaid embodiment, in the form of a film, therefore, it has a greater thickness.

[00085] In particular, preferably, the thermally conductive resin has a thickness such as to be in contact on one side with the respective wall on which it is positioned and on the other side with a surface comprised in the facing component , for example a surface of the stator .

[ 00086 ] According to a preferred embodiment , for example shown in Figure 2 , the thermally conductive resin is positioned in such a way as to axially contact the motor surface 629 and the upper surface of the stator 41 , for example the entire upper surface of the various stator coils .

[ 00087 ] According to a preferred embodiment , the thermally conductive resin is positioned in such a way as to radially contact the stator tubular surface 626 and the inner surface of said stator 41 .

[ 00088 ] In these preferred embodiments , therefore , the presence of the thermally conductive resin is such as to carry out the transmi ssion of heat through it directly, putting the respective walls and surfaces in communication and in contact . In other words , the presence of air between the walls and surfaces concerned is eliminated .

[ 00089 ] According to a preferred embodiment , air is present in the stator chamber 622 and, preferably, in the command chamber 630 , with the exception of the areas in which the thermally conductive resin is present .

[ 00090 ] In a preferred embodiment variant , the stator chamber 622 and, preferably, the command chamber 630 are filled with oil, in such a way as to cool the stator 62 and, preferably, the electronic command board 5, respectively, by convection. In other words, oil wets the areas on which the thermally conductive resin is present. [00091] In other words, the stator 62 and, preferably, the electronic command board 5 are in an oil bath.

[00092] Furthermore, said oil is in contact with the thermally conductive resin and transmits by convection the heat present in said stator chamber 622 and, preferably, in said command chamber 630, to the thermally conductive resin .

[00093] In other words, the cooling of the entire electronic components is further improved, by virtue of the combined presence of oil and thermally conductive resin .

[00094] In one embodiment, oil is present in the stator chamber 622 and in the command chamber 630 in an amount such that it touches the thermally conductive resin in any orientation of the pump group inside the vehicle.

[00095] Preferably, the oil is of the dielectric type, i.e. it does not allow the conduction of electric current in it .

[00096] Preferably, the third casing 63 comprises a closing cover 635 suitable for tightly sealing the command chamber 630 , in which the electronic command board 5 is housed .

[ 00097 ] In a third preferred embodiment variant , the stator chamber 622 and, preferably, the command chamber 630 are entirely filled with thermally conductive resin . In other words , the stator 62 and, preferably, the electronic command board 5 are immersed in the thermally conductive resin .

[ 00098 ] In this way, the cooling of the entire electronic components is further improved, by virtue of the presence of thermally conductive resin which completely covers the stator 62 and, preferably, the electronic command board 5 . [ 00099 ] According to a preferred embodiment , it is noted that the second separation wall 623 comprises at least one fluid passage 623 ' suitable for fluidically connecting the stator chamber 622 and the command chamber 630 .

[ 000100 ] Preferably, said fluid passage 623 ' is suitable for favoring the heat exchange between the stator chamber 622 and the command chamber 630 . Preferably, said heat exchange takes place through the thermally conductive resin or through the oil .

[ 000101 ] According to a preferred embodiment , the thermally conductive resin is positioned on the desired walls , or is positioned inside the desired chambers in a substantially liquid form, to then be polymeri zed and then solidified.

[000102] According to a preferred embodiment, the thermally conductive resin in liquid form has a viscosity lower than 1700mPa*s (or 1700 cP) .

[000103] According to a preferred embodiment, the thermally conductive resin has conductivity greater than 0.3 W/mK, preferably 0.5 W/mK.

[000104] According to a preferred embodiment, the thermally conductive resin has the fastest possible polymerization time. Preferably, the thermally conductive resin in fluid form between 25 and 50°C polymerizes in a time between 3 h and 20 minutes.

[000105] According to a preferred embodiment, the polymerized thermally conductive resin is substantially rubbery, i.e. it is not rigid.

[000106] According to such preferred embodiment, the thermally conductive resin acts as a vibration damping element, being preferably rubbery in nature.

[000107] Innovatively, the pump group fully fulfills the intended object by overcoming the typical problems of the prior art.

[000108] Advantageously, in fact, the pump group comprises thermally conductive resin which covers the surfaces of the pump body proximal to the components being heated, and in particular of the stator, of the rotor and of the command electronics , favoring by conduction the cooling of said components , favoring the heat exchange between said high temperature components and the "hydraulic part" o f the pump body .

[ 000109 ] Advantageously, the heat produced by the electronic components is ef fectively conducted and transmitted through the thermally conductive resin . [ 000110 ] Advantageously, the combined presence of oil and thermally conductive resin allows the cooling of the components being heated to be accentuated, favoring the cooling by convection of said components .

[ 000111 ] Advantageously, the thermally conductive resin is such as to dampen vibrations .

[ 000112 ] Advantageously, in the pump group obj ect of the present invention the " insulating" ef fect which is typically due to the presence of spaces in which air i s present is extremely reduced . Advantageously, in fact , the possibility that the air is an insulating screen for the heat produced by the stator and/or by the command board is obviated .

[ 000113 ] Advantageously, the presence of the stator chamber and the command chamber entirely filled with conductive resin allows the cooling of the components being heated to be accentuated, favoring the cooling by conduction of said components . [000114] Advantageously, the thermally conductive resin allows the pump group to operate at a uniform temperature. Advantageously, the presence of oil in the stator chamber and in the command chamber allows a uniform temperature. [000115] Advantageously, the pump group object of the present invention, with the same dimensions with respect to a known pump group, has greater power. Advantageously, the pump group object of the present invention, with the same power with respect to a known pump group, has more compact dimensions.

[000116] Advantageously, the pump group is positionable inside a vehicle in any spatial position.

[000117] It is clear that a person skilled in the art may make changes to the invention described above in order to meet incidental needs, all falling within the scope of protection as defined in the following claims.

Claims

1. A pump group (1) , for a cooling system for an operating group, such as an engine group, of a vehicle, which extends relative to an axis (X-X) and comprises: i) an impeller (2) rotatable about the axis (X-X) ; ii) a shaft (3) which extends along the axis (X-X) operatively connected to the impeller (2) ; iii) an electric motor (4) comprising a rotor (41) integrally mounted on the shaft (3) and a stator (42) which axially and circumferentially surrounds the rotor (41) ; iv) a pump body (6) comprising, along the axis (X-X) :

- a first casing (61) in which the impeller (2) is housed in an impeller chamber (610) in which refrigerating fluid circulates ;

- a second casing (62) in which the electric motor (4) is housed in a motor chamber (620) , wherein the second casing (62) comprises an intermediate tubular wall (625) which extends parallel to the axis (X-X) positioned between the rotor (41) and the stator (42) so that a rotor chamber (621) and a stator chamber (622) are defined in the motor chamber (620) , wherein the first casing (61) and the second casing (62) are separated by a first separation wall (624) comprising an impeller surface (628) axially facing the impeller (2) and a motor surface (629) axially facing the electric motor

22 (4) ; wherein the pump group (1) comprises a thermally conductive resin which at least partially covers the motor surface

(629) , to cool the stator chamber (622) by conduction through the motor surface (629) .

2. Pump group (1) according to claim 1, wherein the motor surface (629) comprises a rotor portion (6291) which axially faces the rotor (41) , and comprises a stator portion (6292) which axially faces the stator (42) , wherein the thermally conductive resin covers at least in part the stator portion (6292) to cool the stator chamber (622) by conduction through the motor portion (6292) .

3. Pump group (1) according to any one of the preceding claims, wherein the intermediate tubular wall (625) comprises a stator tubular surface (626) radially facing the stator (42) and comprises a rotor tubular surface (627) radially facing the rotor (41) , wherein the thermally conductive resin covers at least in part said stator tubular surface (626) .

4. Pump group (1) according to any one of the preceding claims, comprising a third casing (63) in which an electronic command board (5) is housed in a command chamber

(630) , wherein the second casing (62) and the third casing (63) are separated by a second separation wall (623) , wherein the thermally conductive resin covers at least in part said second separation wall (623) , to cool the command chamber (630) by conduction through said second separation wall (623) .

5. Pump group (1) according to claim 4, wherein the electronic command board (5) is housed in the command chamber (630) in a region proximal to the second separation wall (623) .

6. Pump group (1) according to claim 5, wherein the thermally conductive resin is located between the second separation wall (623) and the electronic command board (5) .

7. Pump group (1) according to any one of claims from 4 to 6, wherein the rotor chamber (621) is fluidically connected to the impeller chamber (61) and wherein the third casing (63) and the second casing (62) delimit an auxiliary cooling chamber (631) fluidically connected to the rotor chamber (621) so that said auxiliary cooling chamber (631) is also fluidically reached by the coolant liquid.

8. Pump group (1) according to claim 7, wherein the second separation wall (623) comprises a central portion (6231) facing the command board (5) in a region proximal to the cooling auxiliary chamber (631) , wherein the thermally conductive resin covers at least in part said central portion (6231) to cool the command chamber (630) by conduction through said central portion (6231) .

9. Pump group (1) according to any one of the preceding claims, wherein the thermally conductive resin also acts as a vibration-dampening element, being preferably of rubbery nature.

10. Pump group (1) according to any one of the preceding claims, wherein the stator chamber (622) is filled with an amount of oil to cool the stator (42) by convection.

11. Pump group (1) according to any one of the preceding claims, wherein the command chamber (630) is filled with an amount of oil to cool the electronic command board (5) by convection.

12. Pump group (1) according to claim 10, wherein the third casing (63) comprises a closing cover (635) which tightly seals the command chamber (630) .

13. Pump group (1) according to the claims from 10 to 12, wherein the oil is of the dielectric type.

14. Pump group (1) according to any one of the preceding claims, wherein the thermally conductive resin positioned on the aforesaid walls and surfaces is in the form of a film.

15. Pump group (1) according to any one of the claims from 1 to 13, wherein the thermally conductive resin positioned on the aforesaid walls and surfaces is in the form of a layer having such a thickness to be in contact on one side with the respective wall on which it is positioned and at

25 the other side with a surface comprised in the facing component, e.g. a surface of the stator.

16. Pump group (1) according to any one of claims from 1 to 9, wherein the stator chamber (622) is filled with thermally conductive resin.

17. Pump group (1) according to any one of the claims from

1 to 9, wherein the command chamber (630) is filled with thermally conductive resin.

18. Pump group (1) according to any one of the claims from 4 to 8, wherein a second separation wall (623) comprises at least one fluid passage (623' ) suitable for fluidically connecting the stator chamber (622) to the command chamber

(630) .