EP3384162B1

EP3384162B1 - Rotor group of a cooling pump of a vehicle cooling circuit comprising a rotor body

Info

Publication number: EP3384162B1
Application number: EP16822535.7A
Authority: EP
Inventors: Stefano Belfiore; Fabio FRANCIA
Original assignee: Industrie Saleri Italo SpA
Current assignee: Industrie Saleri Italo SpA
Priority date: 2015-12-03
Filing date: 2016-11-23
Publication date: 2019-08-07
Anticipated expiration: 2036-11-23
Also published as: CN108350887A; EP3384162A1; ITUB20156281A1; WO2017093855A1; WO2017093856A1; CN108350887B; HUE047690T2

Description

This invention relates to a rotor group of a cooling pump for a cooling system of a vehicle. This invention also relates to the cooling pump that comprises said rotor group and the production method of said rotor group.
Known cooling pumps for a cooling system of a vehicle are typically suitable for moving a predefined quantity of cooling liquid towards predefined components of the vehicle that need to be cooled at specific times of the life cycle and use of the vehicle; these components include the engine, but also the turbo (or turbocharger), the exhaust gas recirculation system and the like.
In the state of the art, electric cooling pumps are known in which the movement of the impeller is obtained by means of an electronically controlled electric motor; these pumps comprise a plurality of components: among others, for example, the impeller, the rotation shaft on which it is mounted, the electric motor group operating on the shaft and the electronic means that control said electric motor.
These pumps, therefore, have several components that require complex manufacturing operations and complex assembly steps.
For the above reasons, these pumps are typically expensive and, given their complexity, often malfunction or have a rather short life cycle.
In order to obviate these problems, some components of these pumps are manufactured to meet high quality standards and they have particularly complex technological solutions.
An example of said known pumps and components is disclosed in document EP1635069A1 .
The purpose of this invention is to provide a rotor group that solves the drawbacks described above linked to the known solutions, such as to provide a limited number of components, obtainable through a simplified production and assembly process.
This purpose is achieved by a rotor group realised according to claim 1, by a cooling pump that comprises the rotor group according to claim 10 and by the production method of the rotor according to claim 11. The claims dependent on these refer to variants of preferred embodiments having further advantageous aspects.
The object of this invention is described below in detail, with the help of the accompanying figures, in which:

Figure 1 is a perspective view in separate parts of a cooling pump comprising a rotor group according to a preferred embodiment of this invention;
Figure 1' is a sectional view of the cooling pump of Figure 1;
Figure 2 is a perspective view of the rotor group of this invention according to a preferred embodiment;
Figure 2 is a sectional view along the plane V-V of the rotor group of Figure 2;
Figures 3a and 3b are, respectively, an impeller-side perspective view and a perspective view on the opposite side of a rotor comprised in the rotor group shown in Figures 2 and 2';
Figure 4 shows a perspective view of the shaft comprised in the rotor group shown in Figures 2 and 2';
Figures 5a, 5b, 5c and 5d illustrate, in section, the moulding production steps of the rotor group according to a preferred embodiment, respectively, the step of accommodating the shaft and the rotor frame in the mould, a first step of injecting fluid material, a second step of injecting fluid material and a third and final step with extraction of the pin elements;
Figures 5a', 5b', 5c' and 5d' show, in perspective views, the production steps of Figures 5a, 5b, 5c and 5d.
Figure 6 is a perspective view in separate parts of a cooling pump comprising a rotor group according to a second preferred embodiment of this invention;
Figure 6' is a sectional view of the cooling pump of Figure 6;
Figure 7 is a perspective view of the rotor group of this invention according to a second preferred embodiment;
Figure 7 is a sectional view along the plane V-V of the rotor group of Figure 7;
Figure 8 shows a side view of the shaft comprised in the rotor group shown in Figures 7 and 7';
Figure 9 shows a sectional view along the plane VI-VI of a rotor group according to the embodiment of Figure 7, but in a second embodiment variant.

In the aforesaid figures, reference number 1 identifies, in its entirety, a rotor group covered by this invention. In particular, this rotor group 1 is used in the automotive sector as a component of a cooling pump 900 of a cooling circuit of a vehicle, as described below.
In a preferred embodiment, the rotor group 1 comprises a shaft 2 that extends along the axis X-X.
Preferably, the shaft 2 is a component in itself; preferably the shaft 2 is made of metal. However, as described below, the shaft 2, in some further embodiments, is an integral part of other components of the rotor group.
According to a preferred embodiment of the invention, the rotor group 1 comprises a rotor 3 fixed to a rotor end 23 of the shaft 2. As described below, the rotor 3 is suitable to be electromagnetically actuated in rotation by a stator 930 in turn controlled by electronic control means 931 (stator 930 and electronic control means 931 in turn comprised in the pump 900, covered by this invention, according to a preferred embodiment); wherein the shaft 2 is integral in rotation with the rotor 3.
So, preferably, the rotation of the rotor 3 corresponds to the rotation of the shaft 2.
According to a preferred embodiment, the rotor 3 includes a rotor frame 30 having a central cavity 320 in which the shaft 2 extends axially.
In a preferred embodiment, the rotor 3 also comprises a plurality of polar cavities 310 arranged, preferably axially, in proximity to or on peripheral walls of the rotor frame 30, wherein said polar cavities are suitable to be engaged by the stator 930.
According to a preferred embodiment, the rotor 3 comprises a plurality of inserts 31 suitable to operate as rotor poles, preferably engaged by respective stator poles.
In the embodiment, in which the rotor frame 30 is provided with polar cavities 310, the inserts 31 are accommodated in said polar cavities 310. In further embodiments of the rotor 3, in which the rotor frame 30 does not have polar cavities 310, the inserts 31 are placed, for example glued, on the outer walls of the rotor frame 30.
Preferably, the inserts 31 are magnetically sensitive, that is to say suitable to be pushed by a magnetic field, to put the rotor 3 and shaft 2 in rotation. Preferably, the inserts 31 are made of ferromagnetic material, for example, are magnetisable.
According to a preferred embodiment, the rotor frame 30 is constituted by a plurality of sheet metal elements 30' axially aligned.
In other words, each sheet metal element 30', preferably made of metal, has on its surface a central opening and a plurality of polar openings, in such a way as to create, once the sheet metal elements 30' are axially aligned, the corresponding central cavity 320 and any polar cavities 310.
Preferably, a sheet metal element 30' at the lateral end of the rotor frame has at least one radial protuberance 310' internally polar opening suitable to axially lock the respective insert 31 inserted axially in the rotor frame 30.
According to a preferred embodiment of the invention, the rotor group 1 comprises a main device 5. Specifically, the main device 5 has the dual function of providing support to the rotor 3 in its engagement with the shaft 2 and allowing rotation and circulation of the cooling liquid in the cooling circuit.
According to a preferred embodiment, the main device (5) is made in a single piece.
According to a further preferred embodiment, the main device 5 is made in two pieces.
Preferably, the main device 5 is in a material chosen from polymeric materials, such as PPS (or polyphenylene sulphide), preferably loaded in glass fibres. In other words, the main device 5 is formed in a semi-crystalline high performance thermoplastic material with excellent mechanical properties (resistance to deformation, rigidity and strength) and excellent thermal and chemical resistance, so as to be suitable to function immersed in the cooling fluid.
Preferably, the main device 5 extends, in height, along the axis X-X.
According to a preferred embodiment, the main device 5 comprises a rotor body 53 suitable to solidly support the rotor 3 at the rotor end 23 of the shaft 2.
Preferably, the rotor body 53 extends from the shaft 2, for example radially, until surrounding the rotor 3 in its entirety.
According to a preferred embodiment, the rotor body 53 is also suitable to lock and cover the inserts 31 placed on the rotor frame 30.
Preferably, the rotor body 53 is suitable to lock the respective inserts 31 in the polar cavities 310, preferably at the opposite side with respect to the side of the rotor frame 30 equipped with sheet metal element 30' comprising radial protuberances 310'.
Preferably, in addition, the rotor body 53 comprises an insulation layer 532 placed between the rotor 3 and the shaft 2. In other words, between rotor frame 30 and shaft 2 there is no contact, so that the rotor 3 is isolated from the external environment also in proximity of the central cavity 320.
In addition, according to a preferred embodiment, the rotor frame 30, in accordance with what is described above, has, parallel to the axis X-X a plurality of through holes 350; in this embodiment, the rotor body 53 comprises a plurality of support pins 530 respectively accommodated in said through holes 350.
According to a preferred embodiment, the main device 5 also comprises an impeller body 54 that extends radially from the shaft 2 at an impeller end 24 opposite the rotor end 23. Preferably, the impeller body 54 is integral in rotation with the shaft 2, and is suitable to control the circulation of cooling liquid in the cooling circuit.
In other words, the main device 5 comprises a radial impeller body 54 that extends radially from the shaft 2. There is no limitation to the geometrical forms of the impeller body 54.
Preferably, the shaft 2 comprises at least one outer surface portion 28 provided with radial cavities to which the main device 5 is suitable to engage integrally. Preferably, both the rotor end 23 and the impeller end 24 have their own outer surface portions 28 provided with radial cavities, for example, they have knurled outer surfaces.
In a preferred embodiment, the main device 5 is moulded, in its entirety, directly around the shaft 2 and rotor 3.
Preferably, the rotor body 53, in its outer wall, has a maximum thickness of less than 1 millimetre, preferably 0.7 mm, so as to allow an effective functioning of the rotor 30 in its electrical engagement with the stator 930 when it is mounted comprised in a cooling pump 900, without affecting the efficiency of the pump.
According to a preferred embodiment, the main device 5 comprises a collar 55 that extends between the rotor body 53 and impeller body 54, in height along the axis X-X radially surrounding the shaft 2.
According to a preferred embodiment, the main device 5 comprises the rotor body 53 moulded, in its entirety, directly around the shaft 2 and the rotor 3. Preferably, the main device 5 comprises an impeller body 54 that is successively fitted on the shaft 2.
This invention also covers the cooling pump 900 of a cooling system of a vehicle comprising the rotor assembly 1 described above.
Preferably, the cooling pump 900 comprises a pump body 912 connectable with the channels (suction and discharge) of the cooling system. In particular, the pump body 912 includes a desired element, connectable with said channels, and a casing element, suitable to house the various components.
Preferably, in a first embodiment variant, the pump body 912 defines a water chamber 914 in which is housed the rotor group 1, i.e., the impeller body 54 and the rotor body 53 containing the rotor 3. Preferably, in the water chamber 914, is identified the impeller chamber 914' specifically suitable to contain the impeller body 54 and a predetermined amount of water placed in motion by it. Furthermore, the pump body 912 delimits a sealed chamber 913, sealingly separated from the water chamber 914, housing a stator group 930 and electronic control means 931 in turn comprised in the cooling pump 900.
Preferably, the stator group 930 is electromagnetically engaged with the rotor 30 on command of the electronic control means 931. In other words, the electronic control means 931 command the action of the stator 930 on the rotor 30 causing it to rotate and inducing in rotation also the impeller body 54.
In a preferred embodiment, the pump body 912, internally to it, comprises a central structure 912' suitable to rotationally support the rotor group 1 and to separate the water chamber 914 and the sealed chamber 913 from each other. Preferably, one end of the rotor group 1, in particular the shaft 2, is rotationally supported by the central structure 912'. Preferably, the pump body 912 comprises a support portion 912" suitable to rotationally support the other end of the rotor group 1.
In a second preferred variant of embodiment, the pump body 912 defines a water chamber 914 in which is housed a portion of the rotor group 1, and in particular its impeller body 54. Preferably, in said water chamber 914, is identified the impeller chamber 914' specifically suitable to contain the impeller body 54 in which the latter is moved in rotation to move the water.
In addition, the pump body 912 defines a rotor chamber 915 suitable to house the rotor body 53 containing the rotor 3.
Furthermore, the pump body 912 delimits a sealed chamber 913, sealingly separated from the water chamber 914, housing a stator group 930 and electronic control means 931 in turn comprised in the cooling pump 900. Similarly to the previously described embodiment, the stator group 930 is electromagnetically engaged with the rotor 30 on command of the electronic control means 931. In other words, the electronic control means 931 command the action of the stator 930 on the rotor 30 causing it to rotate and also inducing the impeller body mounted on it in rotation.
In a preferred embodiment, the pump body 912, internally to it, comprises a central structure 912' suitable to rotationally support the rotor group 1 and to separate the rotor chamber 915 and the water chamber 914 from the sealed chamber 913.
Preferably, moreover, said central structure 912' also comprises a separation and support flange 912''' suitable to separate the water chamber 914 from the rotor chamber 915 and to rotationally support the rotor group 1. Preferably, in fact, the separation and support flange 912''' is suitable to rotationally engage the rotor group 1, in particular, rotationally engaging the shaft 2 being interposed between the rotor body 53 and impeller body 54. Preferably, the separation and support flange 912''' houses an element with low coefficient of friction suitable to allow the rotation of the shaft 2.
Preferably, as shown in Figure 6' by way of example, the rotor group 1 is rotationally supported at one end thereof by the central structure 912', while an intermediate portion is supported by the separation and support flange 912'''.
In addition, this invention also covers the production method of the rotor group 1 described above. This production method is carried out by means of a press, for example a specially shaped mould 700, identifying a rotor compartment 703 and an impeller compartment 704 preferably in communication with each other through a collar compartment 705, wherein said areas have a shape substantially complementary to that of the corresponding components of the rotor group 1.
Preferably, the production method comprises the step of:

housing, in the specially shaped mould 700, the rotor 3 and, possibly, the shaft 2;
injecting liquid material to fill the mould 700, in other words fill the impeller compartment 704, the rotor compartment 703 and the collar compartment 705;
waiting for the material to cool and solidify, constituting the main device 5;
removing the main device 5 from the mould 700.

According to a preferred embodiment, the step of injecting the material is performed by injecting the material in a direction parallel to the axis X-X so that the material fills the impeller compartment 704 first and then the rotor compartment 703.
According to a preferred embodiment, the production method also comprises the step of:

heating the rotor 3 and possibly the shaft 2.

Preferably, the rotor 3 and possibly the shaft 2 are heated to promote the adhesion of the plastic during the moulding step and not create mechanical and thermal stress due to the premature solidification of the material.
Preferably, the production method also comprises the step of:

heating the mould 700 at a predefined temperature and keeping the mould at said temperature.

Preferably, the mould 700 is heated (and is kept in a predefined temperature range) to facilitate the flow of the plastic, avoiding thermal and mechanical stress due to premature solidification of the material. Preferably, the mould 700 is heated to a temperature higher than 145 °C.
Preferably, the press comprises a plurality of pin elements 710 that extend into the rotor compartment 703 of the mould, on which is threaded the rotor frame 30 in the respective through holes 350; when this press is used, the production method also comprises the step of:

axially moving said pin elements 710 parallel to the axis X-X during the injection step of the material, in such a way that the liquid material injected enters inside said through holes 350, closing them and forming the support pins 530.

The production method described above is similarly reproducible for the production of the second embodiment of the rotor group 1 in which the rotor body 53 and impeller body 54 are in two distinct parts. Specifically, this production method is carried out by means of a press, for example using a specially shaped mould 700, identifying a rotor compartment 703 having an area substantially complementary to that of the corresponding components of the rotor group 1.
In other words, it said mould 700 does not have the above described impeller compartment 704 and collar compartment 705, and the step of the method in which the liquid material is injected into the mould 700 has the filling of the rotor compartment 703.
Although the impeller compartment 704 is not present, all the above-described steps are performed in the same manner: for example the step of the injection of the material is performed by injecting the material in a direction parallel to the axis X-X "from top to bottom"; for example, said method is performed again on a press that comprises a plurality of pin elements 710 that extend into the rotor compartment 703 of the mould, on which is threaded the rotor frame 30 in the respective through holes 350. In other words, similarly to what is described above, when this press is used, the production method comprises the step of:

A further characteristic of the rotor group 1 of this invention, in both the "integral" embodiment, i.e., comprising rotor body 53 and impeller body 54, and in the "simple" embodiment, i.e., comprising rotor body 53 and impeller body 54 separated from each other, is that of providing a balancing disc 39, preferably made of metal, on which are executable mechanical operations of removal of material, in such a way as to make recoverable any mass unbalance between rotor 3, rotor body 53 and shaft 2 with respect the rotation axis X-X.
In other words, if in the moulding steps, the rotor 3, and the rotor body 53, are not in axis with the shaft 2 and thus with the axis X-X, by means of specific mechanical operations on the balancing disc 39, the alignment of the masses with respect to the axis X-X is recovered.
Preferably, the balancing disc 39 is positioned at one end of the rotor frame 30' in order to allow the execution of said mechanical operations on it. Preferably, in the moulding operations (similar to those described above) the rotor body 53 is suitable to recover at least partially the balancing disc 39, covering it and locking it. Preferably, the balancing disc 39 is positioned on the bottom of the rotor 3, for example, is housed in the rotor compartment 703 on its bottom.
Innovatively, the rotor group, the cooling pump and the production method of the rotor group of this invention solve the problems of the known art. Advantageously, in fact, only a few components require specific assembly steps, as such components are made in a single process step, in a single piece. In other words, advantageously, the production and assembly of these components is much faster, and less costly.
Advantageously, the rotor group and the cooling pump that comprises it are of extremely compact size compared to prior art solutions: these components thus take up less space than the solutions of the prior art, thus minimising their overall dimensions in the engine compartment of the respective vehicle. Therefore, the rotor group is extremely advantageous from the point of view of saving space in the automotive sector.
A further advantageous aspect lies in the fact that many assembly operations are more reliable since not carried out by operators: for example, in the rotor group of this invention, there is no longer the step of shrink fitting and/or the step of insertion by interference of the impeller and/or rotor on the respective shaft.
A still further advantageous aspect consists in the fact that the rotor body of the main device is suitable to pack block the rotor, and in particular the sheet metal elements that comprise the rotor frame and inserts accommodated in the rotor body.
Advantageously, the rotor body of the main device is suitable to protect the rotor, and particularly the inserts, from external agents, for example the water that wets it, or moisture. Moreover, advantageously, the rotor body isolates the rotor from the other components including the shaft (in the embodiment in which the shaft is in turn comprised in the main device).
A still further advantageous aspect lies in the fact that, in the embodiment with shaft not co-moulded with the other components, said shaft is suitable to maintain the rotor group aligned along its axis.
Advantageously, through the presence of the balancing disc, any misalignments between rotor and shaft in the moulding steps are recovered by simple mechanical operations on said disc.
Innovatively, the production method of the rotor group is simple, since it does not require strong operator skills; in fact, the method is semi-automated.
Advantageously, the heated mould allows a slower and more controlled cooling of the fluid material injected into the mould.
Moreover, advantageously, the heated components accommodated in the mould result in a slower cooling of the fluid material injected, improving the quality of the main device.
It is clear that one skilled in the art, in order to meet contingent needs, may make changes to the pump group, all contained within the scope of protection defined by the following claims.
Moreover, each of the variants described as belonging to a possible embodiment can be realised independently of the other variants described.

Claims

Rotor group (1) of a cooling pump (900) of a cooling circuit of a vehicle, comprising:
- a shaft (2), which extends along an axis (X-X),

- a rotor (3) fixed to a rotor end (23) of the shaft (2) and comprising a rotor frame (30) having a central cavity (320) in which the shaft (2) extends and a plurality of inserts (31) suitable to operate as rotor poles;

- a main device (5) that which extends along the axis (X-X) and comprises:
i) a rotor body (53) which extends from the shaft (2) and surrounds the rotor (3) suitable to integrally support the rotor (3) at the rotor end (23); and

ii) an impeller body (54) which extends radially from the shaft (2) at an impeller end (24) thereof opposite the rotor end (23);

the rotor group (1) being characterized by the fact that the rotor frame (30) has, parallel to the axis (X-X) a plurality of through holes (350), wherein the rotor body (53) comprises a plurality of support pins (530) respectively housed in said through holes (350).
Rotor group (1) according to claim 1, wherein the rotor body (53) is in a material chosen from polymeric materials, such as PPS, preferably loaded in glass fibres.
Rotor group (1) according to any of the preceding claims, wherein which the rotor body (53) is formed directly on the shaft (2), at its rotor end (23) and the impeller body (54) is fitted on the shaft (2) at its rotor end (24).
Rotor group (1) according to any of the preceding claims, wherein the rotor frame (30) delimits a plurality of polar cavities (310) arranged peripherally to the rotor frame (30), in which the inserts (31) are respectively housed and the rotor body (53) is suitable to lock the respective inserts (31) in the polar cavities (310), to the rotor frame (30).
Rotor group (1) according to any of the preceding claims, wherein the rotor frame (30) is constituted by a plurality of sheet metal elements (30') axially aligned.
Rotor group (1) according to any of the preceding claims, wherein the rotor (3) comprises a balancing disc (39) through which is recoverable any mass unbalance between the rotor (3), rotor body (53) and shaft (2) with respect to the rotation axis (X-X).
Rotor group (1) according to any of the preceding claims, wherein the shaft (2) comprises at least one outer surface portion (28) provided with radial cavities to which the rotor body (53) is suitable to engage integrally.
Rotor group (1) according to any of the preceding claims, wherein the rotor body (53) comprises an insulation layer (532) placed between the rotor (3) and the shaft (2).
Rotor group (1) according to any of the claims from 1 to 6, in which the shaft (2) is also an integral part of the main device (5).
Cooling pump (900) of a cooling system of a vehicle comprising a rotor group (1) according to any of the preceding claims, wherein the cooling pump (900) comprises a pump body (912) connectable with the cooling system channels that delimits a water chamber (914) in which is housed a portion of the rotor group (1), such as the impeller (54) preferably in an impeller chamber (914'), delimits a rotor chamber (915) suitable to house the rotor body (53) containing the rotor (3) and delimits a sealed chamber (913) in which is housed a stator group (930) and electronic control means (931), in turn comprised in the cooling pump (900);
wherein the pump body (912) comprises a central structure (912') suitable to separate the water chamber (914) from the rotor chamber (915) and rotationally support the rotor group (1), preferably comprising a separation and support flange (912''').
Production method, using a press, of a rotor group (1) according to any of the claims from 1 to 9, comprising the step of:
- housing in a specially shaped mould (700) identifying a rotor compartment (703), the rotor (3) and/or the shaft (2) ;

- injecting liquid material to fill the mould (700);

- waiting for the material to cool and solidify, constituting the main device (5);

- removing the complete main device (5) from the mould (700) ;
wherein said press comprises a plurality of pin elements (710) which extend in the rotor compartment (703) of the mould (700), on which the rotor frame (31) is inserted in the respective through holes (350);
wherein the production method is characterized by the fact that comprises also the step of:
- axially moving the pin elements (710) parallel to the axis (X-X) during the injection phase of the material, in such a way that the liquid material injected enters inside said through holes (350), closing them and forming the support pins (530).
Production method of a rotor group (1) according to claim 11, wherein the step of injecting the material is performed by injecting the material in a direction parallel to the axis (X-X) so that the material fills the rotor compartment (703) from the top towards the bottom.
Production method of a rotor group (1) according to any of the claims 11 and 12, comprising the step of:
- heating the rotor (3) and possibly the shaft (2) to a predefined temperature.
Production method of a rotor group (1) according to any of the claims from 11 to 13, comprising the step of:
- heating the mould (700) to a predefined temperature and keeping it at said temperature.