Electric machine with a rotor and a cooling device for cooling the rotor in wet operation

Abstract

A wet-operated motor (1) comprising a rotor (2) and a cooling device for cooling the rotor (2), wherein the rotor (2) has a rotor shaft (3) which is at least partially hollow, thereby forming a rotor shaft cavity (4), and wherein the cooling device has a cooling fluid delivery nozzle (5) which extends at least partially into the hollow rotor shaft (3) and through which cooling fluid can be introduced into the rotor shaft cavity (4), wherein the rotor shaft cavity (4) is fluidly connected to an external region (7) of the rotor shaft via at least one opening (6), characterized in that at least one filter element (9) is provided at and / or in the cooling fluid delivery nozzle (5), and / or at and / or in the wall (8) of the rotor shaft cavity (4).

Description

Technical Field

[0001] The present invention relates to a wet-operation motor comprising a rotor and a cooling device for cooling the rotor, wherein the rotor has a rotor shaft, the rotor shaft being at least partially hollow to form a rotor shaft cavity, and wherein the cooling device has a cooling fluid delivery nozzle that extends at least partially into the hollow rotor shaft and through which cooling fluid can be introduced into the rotor shaft cavity, wherein the rotor shaft cavity is in fluid connection with an external region of the rotor shaft via at least one opening. Background Technology

[0002] In wet-operated motors, cooling fluids such as oil, water, or water / glycol mixtures are used to cool or lubricate the active components of the motor.

[0003] The cooling or lubrication system of this type of wet-running motor places high demands on the quality of the cooling fluid—especially on the maximum permissible size of contaminant particles within the cooling fluid.

[0004] Therefore, filters are commonly used to specifically remove contaminant particles from the cooling fluid. The use of such filters varies; however, one of the most common solutions is to install a filter in the area of ​​the cooling fluid pump used to deliver cooling fluid from the cooling fluid reservoir to the components being cooled. Here, the filter can be installed on the suction side and / or the pressure side of the cooling fluid pump.

[0005] On the suction side, upstream of the cooling fluid pump, the pore size of the filter is limited downwards and is also influenced by the available installation space for the filter and, if necessary, the low-temperature suction performance requirements imposed on the cooling fluid pump. Important design parameters depend on the filter pore size, the filter's "wire diameter," and the effective free suction cross-section of the effective filtration surface, also known as the "open screen surface." Here, the reduction in the cross-section when the filter (screen) is at maximum occupancy should be considered. Typically, pore sizes used in automotive transmission applications range from 120µm to 180µm.

[0006] On the pressure side, i.e., downstream of the cooling fluid pump, the filter allows for a smaller sieve size, such as 50µm, thereby achieving a corresponding filter rejection rate (β). x (Value). A disadvantage is the pressure drop caused at the filter, which can have a particularly adverse effect on the operation of cooling fluid pumps at low temperatures. Maintenance-free operation over the service life is typically not achievable with such fine filters. Related to this is the corresponding cost of using geometrically integrated filter elements within the drive housing. Summary of the Invention

[0007] The object of the present invention is to provide an improved wet-operation motor having a rotor and a cooling device for cooling the rotor, the cooling device being particularly characterized by an alternative filtration device for filtering the cooling fluid.

[0008] The aforementioned needs can be met by means of the subject matter according to the invention. Advantageous embodiments of the invention are described herein.

[0009] The motor according to the invention is a wet-operation motor, which uses a cooling fluid such as oil, water or a water-glycol mixture to cool at least one rotor.

[0010] According to the present invention, the wet-operated motor includes a rotor and a cooling device for cooling the rotor.

[0011] According to the invention, the rotor has a rotor shaft, which is at least partially implemented as a hollow shaft, thereby forming an inner cavity of the rotor shaft.

[0012] According to the invention, the cooling device has a cooling fluid delivery nozzle that extends at least partially into a hollow rotor shaft, and cooling fluid can be introduced into the rotor shaft cavity via the cooling fluid delivery nozzle.

[0013] According to the invention, the inner cavity of the rotor shaft is fluidly connected to the outer region of the rotor shaft via at least one opening. The opening may be formed, for example, in the wall of the rotor shaft, and establishes a radial fluid connection between the inner cavity of the rotor shaft and the outer region of the rotor shaft.

[0014] Corresponding to the present invention, at least one filter element is provided at the cooling fluid delivery nozzle and / or in the cooling fluid delivery nozzle, and / or on the wall of the rotor shaft cavity and / or in the wall of the rotor shaft cavity.

[0015] The term "at" in the context should indicate a design scheme in which the filter element is a separate component that can be reversibly or irreversibly fastened to the cooling fluid delivery nozzle and / or the wall of the rotor shaft cavity.

[0016] The term "in..." in the context of this document shall describe a design in which the filter element is an integral part of the wall of the cooling fluid delivery nozzle and / or the inner cavity of the rotor shaft—in which case the wall of the cooling fluid delivery nozzle and / or the inner cavity of the rotor shaft, or more precisely the rotor shaft itself, constitutes the filter element.

[0017] According to the embodiment of the motor of the present invention, a simple pressure-side integration of a filter element can be achieved, which has a smaller achievable sieve size compared to integration on the suction side. This allows for the filtration of smaller contaminant particles from the cooling fluid, thereby protecting the active components of the motor, especially the rotor, from abrasive wear.

[0018] Furthermore, the "foaming" of the cooling fluid can be achieved in a simple way. Any free (undissolved) air components that may be transported with the volumetric flow of the cooling fluid are separated as bubbles or foam by the filter element and can be redissolved in the cooling fluid nozzle and / or rotor shaft cavity.

[0019] Preferably, the filter element is at least partially made of metal mesh.

[0020] In a particularly preferred embodiment of the invention, the cooling fluid delivery nozzle is manufactured from a plastic injection molded part having multiple integrated filter elements made of metal mesh. In this embodiment, the filter elements are thus an integral part of the cooling fluid delivery nozzle, thereby the cooling fluid delivery nozzle itself becomes a filter element.

[0021] This design ensures that, within the axial length of the rotor shaft, the walls of the rotor shaft cavity are uniformly wetted by the cooling fluid flowing through the filter element.

[0022] Furthermore, the available installation space can be optimally utilized.

[0023] The design of a cooling fluid delivery nozzle as a sheet metal part is also conceivable.

[0024] The sieve aperture size of the filter element can be variable or constant in the direction of the cooling fluid flow, that is, within the axial extension range of the filter element.

[0025] The direction description "axial" refers to the direction along or parallel to the central axis of rotation of the rotor shaft.

[0026] The cooling fluid flows primarily axially through the cooling fluid delivery nozzle into the rotor shaft cavity.

[0027] By designing the effective surface area and sieve size of the filter element accordingly, the resulting back pressure can be kept small.

[0028] In a feasible implementation variation of the wet-operated motor, the sieve aperture size of the filter element is implemented to be variable in the direction of the cooling fluid flow, wherein the sieve aperture size increases or decreases in the direction of the cooling fluid flow.

[0029] In this case, it is particularly preferred that the pore size of the filter element increases continuously from 50µm to 120µm in the direction of the flow of the cooling fluid.

[0030] In a favorable implementation variant, the cooling fluid delivery nozzle is implemented with a tapered conical shape in the direction of cooling fluid flow.

[0031] The filter element can be implemented in a tubular form, i.e., in a hollow cylindrical or hollow truncated cone shape, or in a box shape.

[0032] In particular, it is structurally easy to implement that the cooling fluid delivery nozzle is implemented as a filter element, for example, as a rod-shaped filter basket, tubular filter, or filter box. Attached Figure Description

[0033] The invention is described below with reference to the accompanying drawings.

[0034] Figure 1 An exemplary partial longitudinal sectional view of the motor is shown.

[0035] Figure 2 A perspective view of the rotor shaft and a first embodiment of a cooling fluid delivery nozzle for the motor rotor shaft are shown.

[0036] Figure 3 Showing according to Figure 2 A schematic cross-sectional view of the rotor shaft of the cooling fluid delivery nozzle.

[0037] Figure 4 A schematic cross-sectional view of the rotor shaft of a cooling fluid delivery nozzle with a second implementation variant is shown.

[0038] Figure 5 A schematic cross-sectional view of the rotor shaft of a cooling fluid delivery nozzle with a filter element having a constant sieve aperture size is shown.

[0039] Figure 6 A schematic cross-sectional view of a rotor shaft with a cooling fluid delivery nozzle having a filter element with a variable sieve aperture size is shown.

[0040] Figure 7 A perspective view of a third embodiment of a cooling fluid delivery nozzle for an electric motor rotor shaft is shown. Detailed Implementation

[0041] exist Figure 1 The figure shows a partial longitudinal cross-sectional view of motor 1. Motor 1 has a housing 10, a stator fixedly disposed in the housing 2, and a rotor 2 rotatably supported about a central axis of rotation 15 relative to the stator.

[0042] The stator includes a stator core 11 that houses the winding 12, and winding heads 13 are formed at the two axial ends of the stator core.

[0043] The rotor 2 includes a rotor core 14. The rotor core 14 is fixedly positioned, that is, axially fixed and torsionally resisted, on the rotor shaft 3.

[0044] According to Figures 1 to 7 In all embodiments, the rotor shaft 3 is partially hollow, thereby forming an axially extending rotor shaft cavity 4.

[0045] The direction description "axial" refers to the direction along or parallel to the central rotation axis 15 of the rotor shaft 3 of rotor 2.

[0046] The motor 1 also includes a cooling device for cooling the rotor 2. The cooling device has a cooling fluid delivery nozzle 5 that extends partially into the hollow rotor shaft 3. Cooling fluid can be introduced into the rotor shaft cavity 4 via the cooling fluid nozzle 5.

[0047] The direction of flow of cooling fluid within the motor or within the cooling fluid delivery nozzle is schematically shown in the diagram by arrow X, if necessary.

[0048] The cooling fluid delivery nozzle 5 has a nozzle region 16 and a flange region 17, wherein the nozzle region 16 transitions into the flange region 17 of the cooling fluid delivery nozzle 5 at its axial end. The nozzle region 16 extends axially from the flange region 17 and is substantially disposed within the inner cavity 4 of the rotor shaft. The flange region 17 is substantially disposed within the outer region 7 of the rotor shaft 3. The cooling fluid delivery nozzle 5 is fixedly disposed at the housing 10 of the motor 1 via the flange region 17.

[0049] Multiple openings 6 are formed in the wall 8 of the inner cavity 4 of the rotor shaft. The openings 6 establish a radial fluid connection between the inner cavity 4 of the rotor shaft and the outer region 7 of the rotor shaft 3.

[0050] The outer region 7 of rotor shaft 3 is based on Figures 1 to 7 In the current embodiment, the space is limited by the housing 10 of the motor 1.

[0051] The direction description "radial" refers to the direction perpendicular to the central axis of rotation 15 of the rotor shaft 3 of rotor 2.

[0052] According to Figures 1 to 7 In all the illustrated implementation variations, at least one filter element 9 is integrated into the cooling fluid delivery nozzle 5, such that the cooling fluid delivery nozzle 5 itself constitutes the filter element 9.

[0053] Figure 2 and Figure 3Different illustrations of a first embodiment of a cooling fluid delivery nozzle 5, partially disposed within the rotor shaft cavity 4 of the rotor shaft 3, are shown. The cooling fluid delivery nozzle 5 is manufactured as a plastic injection molded part and has a plurality of integrated, i.e., injection-molded or injection-encapsulated filter elements 9 uniformly distributed circumferentially in the nozzle region 16. The nozzle region 16 is substantially configured as a hollow cylinder. The filter elements 9 are each made of metal mesh and each forms a substantially rectangular, axially extending filter surface.

[0054] Figure 4 A second embodiment of the cooling fluid delivery nozzle 5, partially disposed within the rotor shaft cavity 4 of the rotor shaft 3, is shown. The cooling fluid delivery nozzle 5 is manufactured as a plastic injection molded part and has a plurality of integrated, i.e., injection-molded or injection-encapsulated filter elements 9 uniformly distributed circumferentially in the nozzle region 16. The nozzle region 16 is substantially configured as a hollow frustocone with a closed top surface, i.e., the nozzle region 16, thus the cooling fluid delivery nozzle 5, is tapered in the cooling fluid flow direction X. The filter elements 9 are each made of metal mesh and each forms a substantially triangular, axially extending filter surface.

[0055] exist Figure 5 and Figure 6 The diagram illustrates the basis. Figure 2 and Figure 3 The filter element 9, integrated into the cooling fluid delivery nozzle 5, has a constant sieve aperture size. Figure 5 ) and variable sieve aperture size ( Figure 6 ).exist Figure 6 The diagram schematically illustrates how the sieve aperture size of filter element 9 continuously decreases in the flow direction X of the cooling fluid.

[0056] Figure 7 A third embodiment of a cooling fluid delivery nozzle 5, partially disposed within the rotor shaft cavity 4 of the rotor shaft 3, is shown. The cooling fluid delivery nozzle 5 is manufactured as a plastic injection molded part. The nozzle region 16 is substantially configured as a hollow frustocone with a closed top surface. Furthermore, the nozzle region 16 is substantially grid-like in its circumference, wherein the exposed grid surfaces are closed by filter elements 9. The filter elements 1 are each made of metal mesh and each forms a substantially rectangular, axially extending filter surface.

[0057] List of reference numerals

[0058] 1 motor

[0059] 2 rotors

[0060] 3 rotor shafts

[0061] 4. Rotor shaft inner cavity

[0062] 5 Cooling fluid delivery nozzle

[0063] 6 openings

[0064] 7. (Outer region of the rotor shaft)

[0065] 8. (Rotor shaft inner cavity) wall

[0066] 9 filter elements

[0067] 10 (Motor) Housing

[0068] 11 stator core

[0069] 12 windings

[0070] 13 winding heads

[0071] 14 rotor core

[0072] 15 (rotor shaft) central axis of rotation

[0073] 16 nozzle area

[0074] 17 Flange Area

[0075] X. Flow direction of cooling fluid

Claims

1. A wet-operated motor (1), the motor comprising a rotor (2) and a cooling device for cooling the rotor (2), wherein the rotor (2) has a rotor shaft (3), the rotor shaft being at least partially hollow, thereby forming a rotor shaft cavity (4), and wherein the cooling device has a cooling fluid delivery nozzle (5), the cooling fluid delivery nozzle extending at least partially into the hollow rotor shaft (3) and capable of introducing cooling fluid into the rotor shaft cavity (4) via the cooling fluid delivery nozzle, wherein the rotor shaft cavity (4) is fluidly connected to an external region (7) of the rotor shaft via at least one opening (6), characterized in that, At least one filter element (9) is provided at the cooling fluid delivery nozzle (5) and / or in the cooling fluid delivery nozzle, and / or at the wall (8) of the rotor shaft cavity (4) and / or in the wall of the rotor shaft cavity.

2. The wet-operated motor (1) according to claim 1. Its features are, The filter element (9) is at least partially made of metal mesh.

3. The wet-operated motor (1) according to claim 2. Its features are, The cooling fluid delivery nozzle (5) is made of a plastic injection molded part having multiple integrated filter elements (9) made of metal mesh.

4. The wet-operated motor (1) according to claim 1, 2 or 3. Its features are, The sieve aperture size of the filter element (9) is variable or constant in the flow direction (X) of the cooling fluid, that is, within the range of the axial extension of the filter element (9).

5. The wet-operated motor (1) according to claim 4. Its features are, The sieve size of the filter element (9) is variable in the flow direction (X) of the cooling fluid and can increase or decrease in the flow direction (X) of the cooling fluid.

6. The wet-operated motor (1) according to claim 5. Its features are, The sieve size of the filter element (9) increases continuously from 50µm to 120µm in the flow direction (X) of the cooling fluid.

7. The wet-operated motor (1) according to any one of claims 1 to 6. Its features are, The cooling fluid delivery nozzle (5) is tapered in the direction of flow (X) of the cooling fluid.

8. The wet-operated motor (1) according to any one of claims 1 to 7. Its features are, The filter element (9) is implemented in a tubular form, i.e., in a hollow cylindrical or hollow truncated cone shape, or in a box shape.

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