CN114270043A

CN114270043A - Pump and method of operating the same

Info

Publication number: CN114270043A
Application number: CN202080059380.XA
Authority: CN
Inventors: L·奥塔维亚尼
Original assignee: VHIT SpA
Current assignee: VHIT SpA
Priority date: 2019-08-22
Filing date: 2020-08-18
Publication date: 2022-04-01
Anticipated expiration: 2040-08-18
Also published as: EP4018095B1; EP4018095A1; CN114270043B; IT201900014916A1; WO2021032746A1

Abstract

A pump, comprising: -pumping means (2) for pumping a working fluid; -an electric motor (3) for driving the pumping means (2); the electric motor (3) comprises a stator (31) and a rotor (32) interacting to actuate the pumping device (2); the rotor (32) being rotatable about a rotation axis (320); -a housing (8) enclosing a stator (31) of the electric motor (3); -an electronic unit (4) for controlling the electric motor (3); -a conduit (5) for conveying a working fluid downstream of said pumping device (2); -a cooling line (6) for cooling the electric motor (3) and the electronic unit (4), the cooling line (6) drawing the working fluid processed by the pumping device (2). The cooling line (6) comprises: i) at least one first chamber (621) in which the working fluid circulates; said at least one first cavity (621) being defined in part by said stator (31) and in part by said housing (8); ii) a heat exchange manifold (92), to which the first chamber (621) opens and which is used to cool the electronic unit (4); iii) a return manifold (93) located downstream of the heat exchange manifold (92); iv) fluid communication means (63) for communicating fluid from said heat exchange manifold (92) to said return manifold (93); the fluid communication means (63) is at least partially defined by the stator (31).

Description

Pump and method of operating the same

Technical Field

The present invention relates to a pump, in particular a pump known as an ELOP (electric oil pump). It may be used to deliver working fluid to a transmission, such as possibly an electric Axle transmission ("e-axe") or a "torque vectoring" differential or other static or dynamic applications (e.g., for lubrication and/or cooling and/or actuation purposes). This type of pump comprises a pumping device, an electric motor actuating the pumping device and an electronic unit for controlling the electric motor.

Background

There are known ELOP pumps in which some of the working fluid is diverted and flows through a conduit at the motor to cool the motor before being processed by the pumping device. The working fluid is then delivered to an external device served by the pump and located at the delivery end.

The disadvantage of this solution is that the cooling of the motor is not uniform and depends on the installation conditions, in particular on the direction of the motor.

Disclosure of Invention

The object of the present invention is to propose a pump which makes it possible to avoid a drop in the suction pressure, while optimizing the distribution of the fluid and therefore the cooling.

The technical aim and the specific objects are substantially achieved by a pump having the technical features described in one or more of the appended claims.

Drawings

Other characteristics and advantages of the invention will become more apparent from the description of the pump, as illustrated in the accompanying drawings, which description is intended to be indicative and therefore non-limiting, and in which:

figure 1 shows a perspective view of a pump according to the invention;

fig. 2 shows a cross-sectional view of a first constructive solution of the pump according to the present invention;

figures 3 and 4 show cross-sectional views taken along the section B-B, C-C, respectively, of figure 2;

figure 5 shows an alternative to the solution shown in figure 4;

figure 6 shows the components of the pump of figure 2;

figure 7 shows a cross-sectional view of a second constructive solution of the pump according to the present invention;

figure 8 shows a cross-section taken along section a-a of figure 2 or figure 7;

figures 9 and 10 show cross-sectional views taken along the section B-B, C-C, respectively, of figure 7;

fig. 11 shows a further embodiment of the pump according to the invention.

Detailed Description

In the drawings, reference numeral 1 denotes a pump, in particular an ELOP (electric oil pump). Conveniently, the working fluid handled by the pump 1 is oil, but other types of working fluid (generally of the incompressible type) can be handled as well.

The pump 1 conveniently comprises means 2 for pumping the working fluid. Conveniently, the pumping device 2 comprises a gear pumping device (but may alternatively comprise a vane pump, a centrifugal pump or other type of pump). Preferably, the pumping device 2 comprises a first gear and a second gear, which are located one inside the other and are engaged with each other (this solution is also known in the art as gerotor). Conveniently, the pumping device 2 comprises one or more inlets.

The pump 1 further comprises an electric motor 3 for actuating the pumping means 2. Preferably, but not necessarily, the motor 3 is a brushless motor. The electric motor 3 comprises a stator 31 and a rotor 32, which interact to actuate the pumping device 2. The rotor 32 is rotatable about an axis of rotation 320. Conveniently, the pump 1 comprises a drive shaft 33 actuated by the electric motor 3, which drives at least a portion of the pumping means 2 in rotation. The rotor 32 is formed integrally with the shaft 33. On the other hand, the stator 31 is fixed to the pump housing 80. The stator 31 preferably includes windings 310. These windings 310 define pole tips.

The pump 1 conveniently comprises an electronic unit 4 for controlling the electric motor 3. The electronic unit 4 is thus able to regulate the movement of the electric motor 3. The electronic unit 4 is conveniently multifunctional. The electronic unit 4 (e.g., at least one electronic circuit board) is conveniently housed and fixed in the pump housing 80.

The pump 1 may comprise an additional pumping device 200. In this case, the pump 1 may be referred to as a "tandem pump". Conveniently, the additional pumping means 200 are driven by the same motor 3 that drives the pumping means 2. Conveniently, the pumping device 2 and the additional pumping device 200 are coaxial. The additional pumping device 200 may be external to the pump 1 to deliver the working fluid to the same user as the pumping device 2 described above or to a different user. Furthermore, the pumping device 2 and the additional pumping device 200 may be supplied by separate suction ducts. In a preferred solution, the pumping means 2 is closer to the motor 3 than the additional pumping means 200. Conveniently, the pump 1 may comprise a second additional pumping device 2000 (with respect to which the description given above for the additional pumping device 200 may be advantageously repeated). For example, fig. 11 shows a pumping device 2, an additional pumping device 200 and a second additional pumping device 2000.

The pump 1 comprises a duct 5 for conveying a working fluid. The conduit 5 is downstream of the pumping device 2. For example, as mentioned above, it is able to deliver the working fluid (generally oil) to at least one user outside the pump 1.

The pump 1 also comprises a line 6 for cooling the motor 3 and the electronic unit 4. Preferably, the cooling line 6 is permanently open and discharges some of the working fluid processed by the pumping device 2. There is no check valve that impedes the flow of the working fluid or permits flow only when a predetermined pressure is exceeded.

The cooling line 6 conveniently comprises a first conduit 61 developing from the delivery zone 22 of the pumping device 2. The first conduit 61 is therefore a partial bleed flow of the working fluid for cooling the motor 3 and the electronic unit 4. Conveniently, the delivery duct 5 and the first duct 61 develop from two opposite sides of the pumping device 2, respectively. The first conduit 61 has an inlet 610.

The first conduit 61 is conveniently a calibration conduit. Which is conveniently designed and/or formed with a suitable constriction.

Conveniently, in a preferred non-limiting version, the mouth 51 of the delivery duct 5 and the inlet 610 of the first duct 61 face respectively two opposite sides of the pumping device 2. In particular, the delivery duct 5 and the first duct 61 develop from a high pressure region of the pumping device 2. Conveniently, the flow of the working fluid through the first duct 61 is preferably regulated in terms of flow rate or pressure to produce a heat exchange evenly distributed in the electric/electronic parts. The flow of the working fluid is calibrated during the design and testing phases of the pump 1 according to the requirements of the specific application (for example at maximum temperature and at minimum pressure; by doing so, the flow rate of the oil will be ensured to be sufficient for the purpose under all other operating conditions of the pump).

In a preferred installation configuration of the pump 1, the first conduit 61 is located in a lower region of the pump 1. In particular, in the preferred installation configuration, the first duct 61 is located below the rotation axis 320 (this condition being evaluated in the region between two vertical planes located at the inlet and outlet of this first duct 61). In particular, in the preferred mounting configuration, the axis of rotation 320 is in a substantially horizontal position. The motor 3 is thus in the automatic exhaust state.

However, the pump 1 may also be mounted vertically. In this case, the mounting can be carried out in two possible orientations, in particular with the electronic unit 4 on top or bottom. The solution of placing the electronic unit 4 at the bottom is preferred between the two possible orientations, but even if the electronic unit 4 is at the top, the pumping device 2 draws back the working fluid by suction (as will be explained more clearly below), thus still allowing the air to flow out. Alternatively, the pump 1 may be mounted in any orientation and in any orientation intermediate to the described solutions.

Conveniently, the electric motor 3 is interposed between the pumping device 2 and the electronic unit 4. Conveniently, the pump 1 comprises a housing 20 for the pumping device 2, a housing 30 for the electric motor 3 and a housing 40 for the electronic unit 4. The housing 20 for the pumping device 2 and the housing 30 for the electric motor 3 are adjacent to each other. The housing 30, in which the electric motor 3 is located, is in fluid communication with the housing 20, in which the pumping device 2 is located. Conveniently, the housing 30 is at least partially filled with the working fluid (in a preferred version, the housing 30 is completely filled or at least 90% filled). The electric motor 3 is therefore at least partially, preferably completely or at least 90%, immersed in the working fluid. Conveniently, the housing 40, where the electronic unit 4 is located, is separate from the housing 30, where the electric motor 3 is located. Conveniently, the housing 40, in which the electronic unit 4 is located, is hydrodynamically isolated from the housing 30, in which the electric motor 3 is located. This typically occurs by means of a fluid-tight, heat-conducting wall 41. The heat conducting wall is conveniently shaped to optimise heat exchange (for example, it has a smaller thickness in the case where greater cooling is required). The working fluid from the pumping device 2 does not penetrate into the housing 40. The electric motor 3 is cooled and lubricated by the working fluid handled and delivered by the pumping device 2.

As shown in the example in fig. 2, at least one imaginary straight line 7 parallel to the rotation axis 320 intersects the electric motor 3 (stator 31 or rotor 32, the electronic unit 4 and the pumping device 2). These elements are thus distributed axially. As described above, the working fluid for cooling the motor 3 and the electronic unit 4 meets the first conduit 61 downstream of the pumping device 2 (in the present specification, the expressions "upstream" and "downstream" refer to the flow of the working fluid). The first duct 61 develops longitudinally and has a convex orthogonal section (with respect to the longitudinal development).

Conveniently, the first duct 61 defines at least one fluid passage cross-section, which is convex when this cross-section is determined orthogonally to said longitudinal development line. Conveniently, for at least 90% of the longitudinal development, the fluid passage cross-section is convex when determined orthogonal to said longitudinal development line. The working fluid does not contact the shaft 33 within the first conduit 61.

As mentioned above, the inlet 610 of the first conduit 61 faces the pumping device 30.

The pump 1 comprises a housing 8 at least partially enclosing the motor 3. Which forms part of the pump housing 80. The first housing 8 conveniently surrounds the stator 31 and the rotor 32. The pump casing 80 also comprises a cover 81, which cover 81 is joined to said casing 8 and defines the outer casing of the electronic unit 4. The first duct 61 is surrounded and defined by said housing 8. The housing 8 surrounding and defining the first conduit 61 is a single unitary shell. Conveniently, the first duct 61 comprises a plurality of successive portions in which the passage section is progressively reduced. Conveniently, the first duct 61 has at least one passage section defined by a single perimetric line closed on itself and conveniently circular. Preferably, there is no body within the first conduit 61.

The first conduit 61 extends along its development away from the pumping device 2 and away from said axis of rotation 320 of the rotor 32. The first conduit 61 develops until it encounters a region adjacent to the region where the housing 8 is fastened (e.g., by interference fit or bonding) to the stator 31.

As shown in the example in fig. 2 or 7, the first duct 61 has a straight longitudinal development axis. Which develops from the chamber in which the pumping means 2 are located.

Conveniently, the cooling line 6 (in other words, the line intended for cooling the motor 3 and the electronic unit 4) comprises a single outlet line from said housing 20 (chamber) housing the pumping device 2. The outlet line is defined by the first conduit 61. In an alternative, the cooling line 6 may comprise a plurality of outlet lines from the housing 20.

As shown in the example in fig. 7, the cooling line 6 conveniently comprises at least a first cavity 621 in which said working fluid circulates. The first chamber 621 is located downstream of the first pipe 61. The first duct 61 and said first chamber 621 convey the working fluid away from the pumping device 2. Conveniently, the first cavity 621 (in particular at least the section orthogonal to the longitudinal development) is defined partly by the stator 31 and partly by the casing 8. The passage from the first duct 61 to the first chamber 621 is marked, for example, by a change in the direction of the working fluid. However, the working fluid may follow the same direction if desired. Conveniently, the first cavity 621 is defined only by the combination of the stator 31 and the housing 8. The first chamber 621 defines a recess that extends into the housing 8 and not into the stator 31 (so the stator 31 does not have a recess that defines the first chamber 621; instead the portion of the stator 31 that helps define the first chamber 621 is convex). This is because the forming of the housing 8 is less costly than the forming of the stator 31 and can be done, for example, in a forging or casting process; this can reduce costs.

The first chamber 621 is located downstream of the first pipe 61. In the alternative of fig. 7, the first cavity 621 is a continuation of the first duct 61 (but with a different development direction; it may follow the same direction if desired).

In the proposed solution (see, for example, fig. 2-6), the cooling line 6 comprises (and in particular branches to):

a delivery manifold 91 (which may have a constant or variable cross section with respect to the development line; this enables the delivery pressure to be better controlled for the purpose of optimal flow calibration);

a plurality of cavities 62.

In this specification, "manifold" is taken to mean a chamber in which a plurality of conduits and/or gaps and/or cavities develop or from which they begin to develop. It has the function of collecting and/or distributing the working fluid.

Conveniently, the cooling line 6 comprises a plurality of delivery ducts (solution not shown) which conveniently connect the delivery zone 22 of the pumping device 2 to the delivery manifold 91.

Upstream of said at least first cavity 621 (or upstream of the delivery manifold 91), as described above, the cooling line 6 comprises a first duct 61 with a convex section, which develops from the delivery zone 22 of the pumping device 2.

The first conduit 61 leads to the delivery manifold 91 (see fig. 2) or directly to the first chamber 621 (see fig. 7). The first duct 61 and said cavity 62 convey the working fluid away from the pumping device 2.

The first cavity 621 forms a portion of the plurality of cavities 62.

A plurality of cavities 62 develop from the delivery manifold 91. The working fluid flows through the plurality of cavities 62. A plurality of cavities 62 are distributed around the stator 31.

The delivery manifold 91 distributes the working fluid (which is a cooling fluid) to the various chambers 62.

These cavities 62 are defined in part by the stator 31 and in part by the housing 8.

The delivery manifold 91 and the chamber 62 are conveniently calibrated. They are conveniently designed and/or formed with a suitable constriction.

The delivery manifold 91 conveniently has an annular development. Conveniently, it comprises/is a groove formed in said housing 8. The groove is annular. The walls of the delivery manifold 91 are advantageously defined by the stator 31

The first cavity 621 and/or the plurality of cavities 62 and/or the delivery manifold 91 are preferably defined by a recess formed at least partially in the housing 8 (preferably only in the housing 8), typically by forging and/or casting or by using a machine tool after forging and/or casting.

Conveniently, the cavity 62 extends into the housing 8 and not into the stator 31. As mentioned above, the cavity 62 is defined by a recess extending within the housing 8 and facing the stator 31. The cavity 62 may thus be defined by the radiating element. Conveniently, the stator 31 has an outer surface at the cavity 62 that is free of concavities (appears substantially smooth). Conveniently, the stator 31 comprises at least one reference mark 95 (for example a protrusion) for angular positioning with respect to the casing 8. This is useful for phasing the phases. For example, the stator 31 may thus comprise a cylindrical outer surface, except for the at least one angular reference mark 95.

In the alternative, the cavity 62 may be formed at least partially in the stator 31, for example in a stator having projections.

Conveniently, the cavities 62 are distributed at equal circumferential intervals. For example, the cavities 62 may develop parallel to each other. Conveniently, in a preferred but non exclusive solution, they develop longitudinally in a direction parallel (or substantially parallel) to the rotation axis 320 of the rotor 32. In one alternative, they may develop, for example, spirally.

Conveniently, the cooling line 6 comprises a heat exchange manifold 92, to which the first cavity 621 opens, intended to cool the electronic unit 4. Conveniently, the plurality of chambers 62 open into a heat exchange manifold 92. The heat exchange manifolds 92 provide greater uniformity in the outlet pressure of the fluid exiting each chamber 62. The heat exchange manifold 92 contacts the wall 41 of the housing 40.

As shown in the example in fig. 5, at least two of said cavities 62 have a cross section different from each other in at least one plane orthogonal to the rotation axis 320 of said rotor 32 (this is based on the assumption that the pressure drop is greater due to the small passage cross section of the manifold 91). Conveniently, this enables a uniform and even distribution of the flow rate at the inlet of the heat exchange manifold 92 in the circumferential direction. In particular, the cross-section of said cavity 62 increases progressively along the development of the ring.

In particular, the first duct 61 opens into the delivery manifold 91 at a point equidistant from the chamber 62 with the greatest constriction and closest to and opposite to the chamber with the larger section.

In the solution of fig. 4, at least a number of said cavities have sections equal to each other in at least one plane orthogonal to the rotation axis 320 of said rotor 32 (this is based on the assumption that the pressure drop in the manifold 91 is almost negligible) so as to enable a uniform and even distribution of the flow rate at the inlet of the heat exchange manifold 92 in the circumferential direction.

The cooling line 6 conveniently comprises a return manifold 93 downstream of the heat exchange manifold 92.

Conveniently, the heat exchange manifold 92 is annular. Conveniently, the heat exchange manifold 92 is located behind the casing 40 of the electronic unit 4.

The first duct 61 and said first cavity 621 or said cavity 62 convey the working fluid away from the pumping device 2.

Conveniently, the return manifold 93 is annular. Conveniently, it is located on the opposite side of the stator 31 with respect to the heat exchange manifold 92. The stator 31 is completely located between the heat exchange manifold 92 and the return manifold 93

The cooling line 6 further comprises means 63 for communicating fluid from said heat exchange manifold 92 to said return manifold 93. This conveniently occurs by flowing through the stator 31. The means 63 are thus at least partially defined by the stator 31. Conveniently, the stator 31 is in contact with at least some of the fluid flowing through the device 63. Thus, the working fluid flowing through the device 63 contacts the stator 31. Preferably, the device 63 includes all of the gaps (or channels) through which the working fluid flows from the manifold 92 to the manifold 93, and each of these gaps (or channels) is at least partially defined by the stator 31. At least some of the fluid flowing through the device 63 is in contact with the rotor 32.

The fluid communication means 63 includes a plurality of return gaps 630 formed between the heat exchange manifold 92 and the return manifold 93.

Conveniently, the return gap 630 may pass internally through the stator 31.

Preferably, a return gap 630 is formed between the windings 310 of the stator 31. In particular, these return gaps 630 alternate with the windings 310.

In other words, the cooling line 6 comprises a return gap 630, which is hydrodynamically and possibly geometrically parallel, and extends from said heat exchange manifold 92 through the stator 31 of the electric motor 3 towards the pumping device 2. Conveniently, the return gaps 630 join together in the return manifold 93.

Additionally or alternatively, the fluid communication means 63 may comprise an annular return channel 631 defined between the rotor 32 and the stator 31 (air gap).

Conveniently, the housing 8 comprises a stop 96 for the stator 31. The stop 96 develops towards the axis of rotation 320 and preferably has a radial development.

Conveniently, the housing 8 comprises an inner surface 97 which surrounds the stator 31 and is fastened to the stator 31.

Conveniently, the pump 1 comprises a fluid-dynamic sealing zone between the casing 8 and the stator 31. This hydrodynamic seal hydrodynamically separates the delivery manifold 91 (e.g., in the case of the arrangement of fig. 6) or the first chamber 621 (in the case of the arrangement of fig. 2) from the return manifold 93. This prevents the working fluid from bypassing the heat exchange manifold 92. Conveniently, this hydrodynamic sealing region 31 between the housing 8 and the stator is located at the position of the stop 96 and/or at the position of at least a portion of the surface 97.

Conveniently, the pump 1 comprises at least one recirculation channel 64, enabling the working fluid present in the manifold 93 to be recirculated to the pumping device 2. In particular, the passage 64 places said return manifold 93 in fluid communication with a zone (for example of the pump 1) located upstream of the pumping device 2.

The means 63 and the passage 64 conveniently enable (or facilitate) the return of the working fluid to the pumping device 2.

In one version (e.g., as shown in fig. 2 or 7), the recirculation passage 64 connects the return manifold 93 to the first suction region 211 of the pumping device 2. Through this first suction zone 211, the working fluid for cooling the electric motor 3 and the electronic unit 4 is recirculated into the pumping device 2. Conveniently, the pump 1 comprises a second zone 212 for sucking the working fluid into the pumping device 2. Conveniently, the first and

second suction areas

211, 212 face, in a preferred but non-limiting version, two opposite sides of the pumping device 2. The higher pressure of the cooling fluid relative to the fluid drawn into the pumping device 2, combined with the rotation of the pumping device 2, helps prevent the working fluid from flowing back through the recirculation passage 64.

In an alternative, not shown, the recirculation channel 64 may connect the return manifold 93 to a reservoir from which the pump 1 draws the working fluid. The reservoir is typically located outside the pump 1.

The invention results in significant advantages.

First, it can avoid a pressure drop at the time of inhalation. At the same time, it can cool the electronics unit and the motor.

Another significant advantage is that the heat exchange is optimized. In this regard, the first pipe 61 enables the working fluid for cooling to be supplied in a measurable amount.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept as it is characterised. Moreover, all the details may be replaced with other technically equivalent elements. In practice, all materials used, as well as the dimensions, may be any according to requirements.

Claims

1. A pump, comprising:

-pumping means (2) for pumping a working fluid;

-an electric motor (3) for driving the pumping means (2); the electric motor (3) comprises a stator (31) and a rotor (32) interacting to actuate the pumping device (2); the rotor (32) being rotatable about a rotation axis (320);

-a housing (8) enclosing a stator (31) of the electric motor (3);

-an electronic unit (4) for controlling the electric motor (3);

-a conduit (5) for conveying a working fluid downstream of said pumping device (2);

-a cooling line (6) for cooling the electric motor (3) and the electronic unit (4), the cooling line (6) drawing the working fluid processed by the pumping device (2);

characterized in that the cooling line (6) comprises:

-at least one first chamber (621) in which said working fluid circulates; the first cavity (621) being defined in part by the stator (31) and in part by the housing (8);

-a heat exchange manifold (92), to which said at least one first cavity (621) opens and which is used for cooling said electronic unit (4);

-a return manifold (93) located downstream of said heat exchange manifold (92);

-fluid communication means (63) for communicating fluid from said heat exchange manifold (92) to said return manifold (93); the fluid communication means (63) is at least partially defined by the stator (31).

2. The pump according to claim 1, characterized in that the cooling line (6) comprises:

i) a delivery manifold (91);

ii) a plurality of cavities (62) that:

-comprising said first cavity (621);

-develops from said delivery manifold (91);

-is flowed through by said working fluid;

-distributed around said stator (31); the cavity (62) is defined in part by the stator (31) and in part by the housing (8).

3. A pump according to claim 2, wherein the cavity (62) extends into the housing (8) but not into the stator (31).

4. A pump according to claim 2 or 3, wherein at least a plurality of the cavities (62) have cross-sections that are different from each other in the same plane orthogonal to the axis of rotation (320) of the rotor (32).

5. The pump according to any one of the preceding claims, wherein the cavity (62) develops longitudinally in a direction substantially parallel to the axis of rotation (320) of the rotor (32).

6. Pump according to any one of the preceding claims, characterized in that the heat exchange manifold (92) is annular and is located behind a casing (40) of the electronic unit (4).

7. The pump according to any one of the preceding claims, wherein the stator (31) comprises windings (310) able to interact with the rotor (32) to actuate the pumping means (2); said fluid communication means (63) comprising a plurality of return gaps (630) connecting said heat exchange manifold (92) with said return manifold (93); the return gap (630) develops between the windings (310) of the stator (31).

8. The pump according to any one of the preceding claims, wherein the fluid communication means (63) comprise an annular gap (631) defined between the rotor (32) and the stator (31).

9. Pump according to any one of the preceding claims, characterized in that it comprises at least one recirculation channel (64) enabling the working fluid present in the return manifold (93) to be recirculated to the pumping device (2).

10. The pump according to any one of the preceding claims, wherein the cooling line (6) upstream of the at least one first cavity (621) comprises a first duct (61) with a convex cross section, which develops from the delivery zone (22) of the pumping device (2).