Guide device for cooling fluid flowing around winding heads of electric motor and electric motor

Abstract

A guide device for a cooling fluid flowing around a winding head (28) of an electric motor (21), comprising a body (2) having a recess (4) defined by an inner edge (3) for guiding a shaft passing through the electric motor (21); and a guide element (5) protruding from the body (2) in an axial direction and extending in a peripheral direction at a first radial position between the inner edge (3) and an outer edge (6) of the body (2).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of German patent application No. 10 2019113 091.3 filed with the German Patent and Trademark Office on May 17, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The invention relates to a guide device for a cooling fluid flowing around winding heads of an electric machine. The invention also relates to an electric machine. Background Art

[0004] When the motor is running, the stator windings heat up due to their ohmic resistance. The higher the current introduced into the motor, the greater the losses caused by heating. It is generally known to cool the stator windings by means of a cooling fluid. In this regard, it has been proposed to apply a cooling fluid in the form of a spray to the winding heads for cooling purposes.

[0005] Document DE 10 2017 211 135A1 discloses an electric machine having a housing in which a stator having a plurality of winding heads is arranged. The housing has a cooling channel through which a cooling medium can flow. The cooling channel has a circular or circle-segment-shaped annular channel portion, through which the cooling medium is fed to some of the winding heads by spraying through a plurality of openings. The winding heads arranged at the bottom are covered with a cooling medium, which is collected in an oil tank.

[0006] However, when spraying the winding heads, in the case of such motors, the cooling fluid flows to the shaft of the motor and is distributed within the motor due to the rotation of the motor. In doing so, the cooling fluid can flow into the air gap between the rotor and stator of the motor and may cause undesirable drag torques. Summary of the invention

[0007] It is therefore an object of the present invention to provide a possibility for improved distribution of the cooling fluid in an electric machine.

[0008] This object is achieved according to the invention by a guide device for a cooling fluid flowing around a winding head of an electric machine, the guide device comprising a body having a recess defined by an inner edge for guiding a shaft passing through the electric machine, and a guide element which projects from the body in the axial direction and extends in the peripheral direction at a radial position between the inner edge and the outer edge of the body.

[0009] The invention is based on the concept of guiding the cooling fluid in the peripheral direction around the shaft, and in particular also around the air gap between the stator and the rotor of the electric machine, by means of a guide element, so that undesired distribution of the cooling fluid through the rotating shaft, as well as penetration into the air gap, is hindered or completely suppressed. The distribution of the cooling fluid in the electric machine is thus improved; undesired drag torques during the operation of the electric machine can be reduced or completely avoided.

[0010] The cooling fluid is usually a cooling liquid, in particular a cooling oil.

[0011] In the case of the guide device according to the present invention, preferably, the device further comprises a second guide element which protrudes from the main body in the axial direction and extends in the circumferential direction in a second radial direction between the first radial position and the outer edge of the main body. The second guide element is used to receive the cooling fluid flowing in the direction of the bottom of the motor due to gravity, and once the cooling fluid flows downward from the first guide element, the cooling fluid is allowed to selectively flow around the lower winding head of the stator winding for cooling.

[0012] In this regard, it is preferred that the centers of the guide elements are arranged centrally in the peripheral direction so as to be connectable via a line crossing the center points of the recesses.

[0013] Advantageously, in the region of the center, a discharge opening for the cooling fluid is formed in the circumferential direction of the second guide element. Thus, the cooling fluid can be effectively discharged as soon as it reaches the lowest point of the second guide element. It is preferably provided here that the second guide element has a radial indentation which leads to the discharge opening formed in the body.

[0014] According to an advantageous embodiment of the guide device according to the invention, it is provided that a radially outwardly pointing elevation is formed at the free end of the first guide element and / or a radially inwardly pointing elevation is formed at the free end of the second guide element. The elevation provides a corresponding guide element with a trough-like structure, which in the case of the second guide element hinders or prevents axial leakage of the cooling fluid from the guide device and in the case of the first guide element hinders or prevents such leakage of the cooling fluid to an even greater extent and is in particular capable of selectively guiding the cooling fluid to the discharge opening.

[0015] Generally, preferably, the first guide element and the second guide element form one or two overlapping regions extending in the circumferential direction.

[0016] The first guide element preferably extends in the peripheral direction over at least 150 degrees, preferably at least 170 degrees, particularly preferably at least 175 degrees, and / or at most 200 degrees, preferably at most 185 degrees, particularly preferably at most 180 degrees. The second guide element may also extend in the peripheral direction over at least 150 degrees, preferably at least 170 degrees, particularly preferably at least 175 degrees, and / or at most 210 degrees, preferably at most 200 degrees, particularly preferably at most 185 degrees.

[0017] Alternatively, it can be provided that the first guide element and / or the second guide element extends fully around the recess in the peripheral direction.

[0018] The guide device according to the invention is particularly preferably formed from a plastic material.

[0019] The object forming the basis of the invention is also achieved by an electric machine comprising a stator with a stator winding and a guide device according to the invention arranged on an end face, wherein a first guide element is arranged radially inside a winding head of the stator winding. Other guide devices according to the invention are appropriately arranged on other end faces.

[0020] It can be provided that the second guide element is arranged outside the winding head in a radial direction.

[0021] In order to effectively hinder or prevent the cooling fluid from penetrating into the air gap, the motor according to the present invention advantageously further comprises a rotor arranged inside the stator to form an air gap, wherein the radially outermost portion is located further outwardly than the air gap on the free end of the first guide element.

[0022] A coolant feed is also preferably provided in the electric machine according to the invention and is arranged in such a way that the cooling fluid is introduced into the first guide element so as to flow around the first guide element in the peripheral direction. Particularly preferably, the coolant feed is arranged such that the cooling fluid is introduced into the first guide element in the radial direction. The coolant feed can have a plurality of supply openings, in particular distributed in the peripheral direction.

[0023] The guide device is preferably fixed to the end plate of the electric machine. The guide device can thus be easily retrofitted to existing electric machine constructions.

[0024] However, alternatively, it is also conceivable that the guide device is formed integrally with the end plate of the electrical machine.In order to provide electrical insulation of the guide device, the end plate may be powder-coated, for example.

[0025] The stator windings are particularly preferably formed as hairpin windings.

[0026] All embodiments of the guide device according to the invention can be transferred to the electric machine according to the invention and therefore the advantages described above can also be achieved with the electric machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Further advantages and details of the invention will become clear from the exemplary embodiments described below and with reference to the accompanying drawings. These are schematic diagrams and show:

[0028] Figure 1 is a perspective view of an exemplary embodiment of a guiding device according to the present invention;

[0029] Figure 2 for Figure 1 An axial plan view of the guide device shown;

[0030] Figure 3 is a perspective cross-sectional view of an exemplary embodiment of a motor according to the present invention;

[0031] Figure 4 is a detailed perspective view of the electric motor in the region of a first guide element of the guide device; and

[0032] Figure 5 The figure shows a detailed perspective view of the electric motor in the region of the second guide element of the guide device. DETAILED DESCRIPTION

[0033] Figure 1 is a perspective view of an exemplary embodiment of the guide device 1 .

[0034] The guide element comprises a body 2 having a recess 4 defined by an inner edge 3, and a first guide element 5 protruding from the body 2 in an axial direction and extending in a peripheral direction at a first radial position between the inner edge 3 and an outer edge 6 of the body 2. The guide device 1 further comprises a second guide element 7 protruding from the body 2 in an axial direction and extending in a peripheral direction at a second radial position between the first radial position and the outer edge 6. The entire body 2 is formed of an electrically insulating material, in this specific case of a plastic material.

[0035] To this end, the body 2 has a first portion 8a, which is defined by the edge 3 and which extends along a radial plane, and a second portion 8b, which is defined by the outer edge 6 and which is axially angled relative to the first portion 8a. Figure 1 On the first side of the body 2 visible in FIG. 1 , the first guide element 5 is arranged in the transition region between the first portion 8a and the second portion 8b and is fixed to the first portion 8a by means of an additional radially inwardly directed reinforcing element 9. The second guide element 7 protrudes axially from the second portion 8b of the body and is reinforced by an additional radially outwardly directed reinforcing element 10.

[0036] The discharge opening 11 is formed in the body 2 in a region in the middle of the second guide element. The discharge opening 11 passes through the second portion 8b of the body 2. In addition, a radially outwardly directed indentation 12 is formed in the second guide element 7 and opens into the discharge opening 11.

[0037] At the free end of the first guide element 5, a radially outwardly directed elevation angle 13 is formed, which will refer to Figure 4 This will be explained in more detail later. At the free end of the second guide element 7, a radially inwardly directed elevation angle 14 is formed, which will be referred to as Figure 5 This is explained in more detail later.

[0038] In addition, the body 2 has a plurality of through openings 15 formed in the second portion 8b in the peripheral direction, which can be used to fix the guide device 1 in place or to guide the cooling fluid to the first guide element.

[0039] Figure 2 for Figure 1 A lateral axial plan view of the guide device 1 is shown.

[0040] The first guide element 5 extends in the peripheral direction over an angular range of 180°. In contrast, the second guide element 7 extends over an angular range of approximately 195°, so that the guide elements 5, 7 form two overlapping areas 16a, 16b. The centers 17, 18 of the guide elements 5, 7 are arranged such that a line 19 connecting the centers 17, 18 crosses a center point 20 of the recess 4.

[0041] Figure 3 is a perspective sectional view of an exemplary embodiment of an electric machine 21 in the region of a first end face.

[0042] The motor 21 includes a stator 22 and a rotor 23, with an air gap 24 formed between the stator 22 and the rotor 23; a motor housing 25 and an end plate 26. Figure 3 The motor 21 has a further end plate (B end plate) on its second end face. The guide device 1 according to the previously described exemplary embodiment is arranged on each of these end plates 26. The motor 21 is a prime mover for electrically driving the vehicle.

[0043] The stator 22 has a stator winding 27 which is formed as a hairpin winding. A winding head 28 of the stator winding 27 protrudes from the stator 22 in the direction of the end plate 26. The first guide element 5 is arranged radially inside the winding head 28, and the second guide element 7 is arranged radially outside the winding head 28.

[0044] The electric machine 21 also has a coolant supply 29 which is arranged in such a way that the cooling fluid is introduced into the first guide element 5 so as to flow around the first guide element in the peripheral direction. Figure 2 ), the cooling fluid flows downward from the first guide element 5 to the second guide element 7 due to the force of gravity acting in the direction of the motor bottom 30. From there, the cooling fluid flows around the other winding heads 28 and passes through the lowest point of the second element 7 into the outlet 11 (see Figure 1 ).

[0045] Figure 4 is a detailed perspective view of the electric machine 21 in the region of the first guide element 5. As can be seen, the radially outermost portion of the first guide element 5 is located further radially outwards than the air gap 24. The elevation angle 13 prevents axial leakage of cooling fluid from the guide device 1 into the air gap 24.

[0046] Figure 5 Detailed perspective view of the electric machine 21 in the region of the second guide element 7. Here, the elevation angle 14 prevents the cooling fluid from leaking axially from the guide device 1 and leaving the guide device 1 instead of through the outlet 11 (see Figure 1 ).

Claims

1. A guide device (1) for a cooling fluid flowing around a winding head (28) of an electric machine (21), wherein: The guiding device comprises: - a body (2) having a recess (4) defined by an inner edge (3) for guiding the shaft through the motor (21), a first guide element (5) which projects from the body (2) in the axial direction and extends in the peripheral direction at a first radial position between the inner edge (3) and the outer edge (6) of the body (2), and a second guide element (7) which projects from the body (2) in the axial direction and extends in the peripheral direction at a second radial position between the first radial position and the outer edge (6) of the body (2), wherein an outlet (11) for the cooling fluid is formed in the region of a center (18) in the peripheral direction of the second guide element (7), The second guide element (7) has a radial indentation (12), which leads to the discharge opening (11) formed in the main body (2).

2. The guiding device according to claim 1, wherein The centers (17, 18) of the first guide element (5) and the second guide element (7) in the peripheral direction are arranged to be connectable via a line (19) that crosses a center point (20) of the recess (4).

3. The guiding device according to claim 1 or 2, wherein The first guide element (5) and the second guide element (7) form one or two overlapping areas (16a, 16b) extending in the peripheral direction.

4. The guiding device according to claim 1 or 2, wherein A radially outwardly directed elevation angle (13) is formed at the free end of the first guide element (5), and / or a radially inwardly directed elevation angle (14) is formed at the free end of the second guide element (7).

5. The guiding device according to claim 1 or 2, wherein The guide device is made of plastic material.

6. An electric machine (21) comprising a stator (22) having a stator winding (27) and a guide device (1) according to any one of claims 1 to 5 arranged on an end face, wherein: The first guide element (5) is arranged in a radial direction on the inner side of the winding head (28) of the stator winding (27).

7. The electric machine according to claim 6, when it is dependent on claim 1, wherein The second guide element (7) is arranged outside the winding head (28) in the radial direction.

8. The electric machine according to claim 6 or 7, further comprising A rotor (23) is arranged inside the stator (22) so as to form an air gap (24), wherein: The radially outermost portion is located at the free end of the first guide element (5) further radially outward than the air gap (24).

9. The electric machine according to claim 6 or 7, further comprising A coolant supply (29) is arranged in such a way that a cooling fluid is introduced into the first guide element (5) so as to flow around the first guide element in the peripheral direction.

10. The electric machine according to claim 6 or 7, wherein The guide device (1) is fixed to an end plate (26) of the motor (21).

11. The electric machine according to claim 6 or 7, wherein The stator winding (27) is formed as a hairpin winding.

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