A mechanism comprising an electric motor rotor and a ring attached to the rotor

Abstract

The invention relates to a mechanism comprising: • an electric motor rotor comprising a rotor shaft extending along a first axis, and a circular structure arranged at one end of the rotor shaft in a plane perpendicular to the first axis, the circular structure comprising at least one rotor tooth and at least one electrical wire winding arranged around the at least one tooth; and • a ring attached to the circular structure so as to surround the circular structure, characterized in that the ring comprises a set of through holes, each through hole being arranged to intersect a radial plane containing the first axis and passing through the center of the electrical wire winding arranged around the at least one tooth, thereby creating circulation of cooling fluid through the winding.

Description

[0001] This invention relates to a mechanism comprising an electric motor rotor and an annular member attached to the rotor. The invention also relates to an electric motor including the mechanism according to the invention. The invention further relates to a vehicle equipped with such an electric motor. The invention also relates to a method for manufacturing the annular member of the mechanism according to the invention.

[0002] Rotary electric machines have very high performance. However, the process of manufacturing such machines presents significant challenges, particularly in improving the reliability of electric motors (especially electrically excited synchronous motors) and increasing the rotational speed of the motor's rotor.

[0003] For this purpose, optimizing the cooling of the rotor and stator windings of the electric motor is crucial.

[0004] Document FR3059487 discloses an annular element for holding rotor windings, which allows for improved cooling of the rotor windings.

[0005] However, this solution has drawbacks. In particular, it creates a circulation of cooling fluid in the air gap adjacent to the rotor. Furthermore, this solution cannot optimize the cooling of the stator windings.

[0006] The object of this invention is to provide a mechanism and a method for manufacturing an annular member for such a mechanism, the mechanism comprising an electric motor rotor and an annular member attached to the rotor, which overcomes the aforementioned disadvantages and improves upon mechanisms known in the prior art that include an electric motor rotor and an annular member attached to the rotor. In particular, this invention enables the realization of a simple and reliable mechanism and method, improves the reliability of the electric motor, and allows for an increase in the rotational speed of the rotor of such a motor.

[0007] Therefore, the present invention relates to a mechanism comprising:

[0008] • Electric motor rotor, the electric motor rotor includes

[0009] o Rotor shaft, which extends along a first longitudinal axis, and

[0010] A circular structure is arranged at one end of a rotor shaft in a first plane perpendicular to a first axis. The circular structure includes at least one tooth of the rotor and at least one wire winding arranged around the at least one tooth.

[0011] • A ring-shaped component that is attached to a circular structure to enclose the circular structure.

[0012] Furthermore, the annular component includes a set of through holes, each of which is arranged to intersect a radial plane containing a first longitudinal axis and passing through the center of the wire winding arranged around the at least one tooth, so as to generate circulation of cooling fluid through the wire winding.

[0013] In one embodiment, the annular element is capable of holding the rotor's wire windings in place.

[0014] In one embodiment, a through hole is arranged at a rounded corner of the annular member, the rounded corner being located between a tubular portion of one annular member centered on a second longitudinal axis and a given surface of the other annular member perpendicular to the second longitudinal axis.

[0015] In one embodiment, the ring-shaped element comprises:

[0016] - A first component, comprising a tubular portion, rounded corners, and a given surface, and

[0017] - A second component, which is in particular in the form of a disc and fastened to a given surface of the first component.

[0018] In one embodiment, the mechanism further includes a stator arranged around an annular element, and a second component provides a guiding surface for cooling fluid flowing through through-holes in the annular element to orient the cooling fluid toward the wire windings of the stator.

[0019] In one embodiment, the through-hole in the annular member is arranged to be traversed by a second plane perpendicular to the first longitudinal axis, the second plane passing through the center of at least one wire winding of the stator.

[0020] In one embodiment, the mechanism includes at least one nozzle designed to deliver cooling fluid to the vicinity of a winding arranged around the at least one tooth.

[0021] The projection of one end of the at least one nozzle onto a third plane passing through the through-hole and perpendicular to the first longitudinal axis lies substantially on a straight line connecting the through-hole in the annular member to the intersection of the third plane and the first longitudinal axis.

[0022] In one embodiment, each through-hole in the annular member has an oblong or oval shape, and / or the smaller dimension of each through-hole is measured along a second longitudinal axis.

[0023] The present invention further relates to an electric motor including a mechanism according to the invention.

[0024] The present invention also relates to a motor vehicle comprising a mechanism according to the invention and an electric motor according to the invention.

[0025] Furthermore, the present invention relates to a method for manufacturing a ring-shaped component of a mechanism according to the present invention, the method comprising:

[0026] • The drilling step, namely, drilling a through hole in a given portion of the first component of the cylindrical workpiece intended to form a ring, the given portion being defined along the longitudinal axis of the cylindrical workpiece, then...

[0027] • The stamping step, namely, stamping the cylindrical workpiece so that a given portion can be bent, thereby placing a given end of the cylindrical workpiece in a plane perpendicular to the longitudinal axis of the cylindrical workpiece, then...

[0028] • Fastening step, i.e., fastening the second part of the ring to a given end.

[0029] Other details, features, and advantages will become clearer after reading the detailed description given below, with reference to the various exemplary embodiments illustrated in the accompanying drawings, in a non-limiting manner:

[0030] [ Figure 1 The illustration schematically shows a motor vehicle equipped with a mechanism according to the invention.

[0031] [ Figure 2 [Illustration 1] is a perspective view of the annular component of the mechanism according to the present invention.

[0032] [ Figure 3 [Illustration 1] is a cross-sectional view of the mechanism according to the present invention.

[0033] [ Figure 4 [Illustration 1] is a longitudinal cross-sectional view of the mechanism according to the present invention.

[0034] [ Figure 5 [Illustration 1] is a perspective view of a ring-shaped component without the mechanism for implementing the present invention.

[0035] [ Figure 6 [ ] is a cross-sectional view of a mechanism that does not implement the present invention.

[0036] [ Figure 7 [ ] is a longitudinal cross-sectional view of the mechanism in which the present invention is not implemented.

[0037] The following is a reference [ Figure 1 This describes one embodiment of a motor vehicle 100. The motor vehicle 100 may be a vehicle with electric or hybrid power drive. Similarly, the vehicle 100 may be a private vehicle, a multi-purpose vehicle, or a vehicle intended for public transportation.

[0038] The motor vehicle 100 is equipped with an electric motor 1 of the rotary electric machine type, which includes a rotor 2 and a stator 3. The rotor 2 forms part of the mechanism 10 according to the invention.

[0039] The mechanism 10 according to the present invention includes:

[0040] - Rotor 2, the rotor includes

[0041] i) Rotor shaft 21, which extends along a first longitudinal axis X1, and

[0042] ii) A circular structure 22, arranged at one end of the rotor shaft 21 and extending in a first plane P1 perpendicular to the first axis X1, the circular structure 22 including at least one tooth 221 of the rotor 2 and wire windings 222 arranged around the at least one tooth 221, and

[0043] - Ring member 4, which is attached to the circular structure 22 to enclose the circular structure 22.

[0044] In addition, the annular member 4 includes a set of through holes 41, each of which is arranged to intersect a central radial plane PRM containing a first longitudinal axis X1 and passing through the center of a wire winding 222 arranged around at least one tooth 221, so as to generate circulation of cooling fluid through the wire winding 222.

[0045] In one embodiment, the hole 41 may be arranged to intersect a radial plane PR1 containing a first longitudinal axis X1, with plane PR1 forming an angle of several degrees with an intermediate radial plane PRM. Thus, a tolerance of several degrees can be applied to the radial alignment between the hole 41 and the center of the wire winding 222, which defines the “intermediate region” of the winding 222.

[0046] In the remainder of this document, the wire winding 222 is also referred to as bundle 222. The mechanism 10 advantageously includes a plurality of bundles 222, each bundle 222 capable of...

[0047] - Wrapped around one tooth of the circular structure 22, or

[0048] - Wrapped around two adjacent teeth of the circular structure 22, or

[0049] - Wrapped around two non-adjacent teeth of the circular structure 22.

[0050] In the remainder of this document, the first longitudinal axis X1 is assumed to be oriented toward the annular member 4.

[0051] refer to[ Figure 2 Furthermore, a second longitudinal axis X2 is defined, corresponding to the longitudinal axis of the annular member 4. When the annular member 4 is integrated into the mechanism 10, the first longitudinal axis X1 and the second longitudinal axis X2 coincide.

[0052] An embodiment of the circular structure 22 of the mechanism according to the invention is in Figure 3 andFigure 4 This can be seen more specifically in the text. Figure 3 [This is a cross-sectional view of mechanism 10, that is, a cross-sectional view formed in a plane perpendicular to the first longitudinal axis X1.] Figure 4 [Illustration 1] is a partial view of the longitudinal section of mechanism 10, that is, a partial view of the section formed in the plane containing the first longitudinal axis X1.

[0053] In the embodiments of the invention described in this document, one of the functions of the annular element 4 is to hold the rotor winding in place.

[0054] Figure 3 and Figure 5 The geometry of the annular component 4 of the mechanism 10 according to an embodiment of the present invention is shown.

[0055] In one embodiment, the through hole 41 is arranged at the rounded corner 421 of the annular member 4, which is located between the tubular portion 420 of the annular member 4 centered on the second longitudinal axis X2 and the given surface 422 of the annular member 4 on the other hand, which is perpendicular to the second longitudinal axis X2.

[0056] Therefore, the through hole 41 is created on the curved material thickness.

[0057] Furthermore, the annular component 4 includes a first component 42 and a second component 43 that are separate from each other, and a means 44 for fastening the second component 43 to the first component 42.

[0058] - The first component 42 includes a tubular portion 420, a rounded corner 421, and a given surface 422, and

[0059] - The second component 43 is in the form of a disc and is fastened to a given surface 422 of the first component 42.

[0060] The fastening device 44 can be achieved by means of screws.

[0061] The second component 43 of the annular member 4 is used to balance the rotor 2. In particular, the second component 43 can be drilled to improve the rotation of the rotor 2, especially to reduce imbalance.

[0062] The through holes 41 in the annular component 4 are distributed at an angle around the second longitudinal axis X2 on the rounded corner 421, as shown in [ Figure 2 This can be seen more specifically in the text.

[0063] Furthermore, the through-holes 41 in the annular component have an oblong or oval shape, and / or the smaller dimension of each through-hole is measured along the second longitudinal axis X2. In other words, the dimension of a given hole 41 measured along the longitudinal axis X1 is strictly smaller than the dimension of a given hole 41 measured along a dimension perpendicular to the longitudinal axis X1.

[0064] When the annular component 4 is installed in the mechanism 10, the corresponding first longitudinal axis X1 and second longitudinal axis X2 are substantially coincident.

[0065] The stator 3 of mechanism 10 is arranged around the annular member 4, and the second component 43 provides a guiding surface 431 for cooling fluid flowing through the through-hole 41 in the annular member 4, so as to orient the cooling fluid toward the wire winding 32 of the stator 3. For this purpose, the surface 431 may be non-planar in order to facilitate the flow direction of the cooling fluid toward the bundle 32.

[0066] Furthermore, advantageously, the through hole 41 in the annular member 4 is arranged to be traversed by a second plane P2 perpendicular to the first longitudinal axis X1, the second plane P2 passing through the center of at least one wire winding 32 of the stator 3.

[0067] In one embodiment, the center of winding 32 may be separated from plane P2 by a small longitudinal distance, for example, a few millimeters. Thus, a tolerance of a few degrees can be applied to the alignment between hole 41 and the center of wire winding 32, which defines the “middle region” of winding 32.

[0068] The bundle 222 is cooled by the circulation of cooling fluid. In one embodiment, the cooling fluid is delivered toward the bundle 222 through nozzles 6 (not shown). Advantageously, the nozzles 6, particularly the ends 61 of the nozzles 6, are distributed around the rotor shaft 21 on a circle 62 centered on the axis X, and are correspondingly located opposite each bundle 222, particularly opposite the middle region of each bundle.

[0069] The circle 62 (on which the ends 61 of the nozzles 6 are distributed) is preferably defined in a plane perpendicular to the first longitudinal axis X1. Advantageously, the projection of the end 61 of each nozzle onto a third plane P3 that passes through the through hole 41 and is perpendicular to the first longitudinal axis X1 lies substantially on a straight line connecting the through hole 41 in the annular member 4 to the intersection point C2 between the third plane P3 and the first longitudinal axis X1.

[0070] The path of the cooling fluid in the mechanism according to the invention is in [ Figure 4The arrows 11, 12, 13, and 14 indicate this. Nozzles 6, distributed around circle 62 opposite each rotor bundle 222, distribute cooling fluid in a direction 11 perpendicular to the rotor bundle 222. The surface of the bundle 222 then guides the fluid in a direction 12, substantially oriented towards the orifice 41 located opposite the bundle 222. After flowing along the bundle 222, the fluid changes direction 13, which orients the fluid towards the guide surface 431 located opposite the middle region of the stator bundle. The fluid then follows the direction 14 guided by the guide surface 431 and reaches the middle region of the stator bundle.

[0071] The present invention further relates to a method for manufacturing an annular member 4 of the mechanism 10 according to the present invention, the method comprising:

[0072] • Drilling through hole step E1, that is, drilling through hole 41 in a given portion 421 of the first component 42 of the cylindrical workpiece intended to form a ring, the given portion 421 being defined along the longitudinal axis X1 of the cylindrical workpiece, then

[0073] • Stamping step E2, that is, stamping the cylindrical workpiece so that the given portion 421 can be bent, thereby placing the given end 422 of the cylindrical workpiece in a plane perpendicular to the longitudinal axis X1 of the cylindrical workpiece, then

[0074] • Fastening step E3, that is, fastening the second part 43 of the annular member 4 to the given end 422.

[0075] In step E1, a through hole 41 is drilled in a given portion 421 of the first component 42 of the cylindrical workpiece, which is defined along the longitudinal axis X1, to form a ring. In other words, the hole 41 on the ring 4 is drilled in a given portion of the cylinder intended to be stamped during step E2.

[0076] In step E2, a portion 421 of the first component 42 is stamped, which has the effect of bending the portion toward the interior of the cylinder. The first section 421 at the bent end then has an arc-shaped profile. The second section 422 at the bent end extends in a plane perpendicular to the longitudinal axis X1. The second section 422 then provides a fastening surface 4221 for the second component 43 of the annular member 4.

[0077] Next, in step E3, the second component 43 is fastened to the fastening surface 4221 of the given end 422. In one embodiment, the second component 43 is threaded to the fastening surface 4221.

[0078] Therefore, unlike the annular part described in patent FR3059487, in the manufacturing method according to the present invention, the cylindrical portion of the annular part is not manufactured by stamping. This difference allows for improved fit between the cylindrical portion of the annular part and its adjacent portions. This reduces the risk of air gaps forming between the cylindrical portion and adjacent components. Consequently, the loss of cooling fluid in the cooling circuit of the electric motor 1 is reduced.

[0079] Another difference between this invention and that described in patent FR3059487 is the fact that drilling is performed before the stamping operation, which limits the risk of cracks forming around the hole during drilling. Furthermore, the fact that stamping occurs after drilling makes it easy to obtain holes in the curved areas of the annular member 4.

[0080] Thus, an annular component 4 was obtained, which was intended to be arranged in mechanism 10.

[0081] Compared to the description in patent FR3059487 and by Figures 5 to 7 In terms of the prior art, the shape of the annular member 4 of the mechanism 10, and in particular the axial and angular positioning of the through hole 41, is advantageous.

[0082] The technical solution described in patent FR3059487 employs an annular member 8, which differs from the annular member 4. One difference lies in the longitudinal position of the holes 81 on the annular member 8, which are located in the middle region of the cylinder formed by the annular member 8. Therefore, the holes 81 on the annular member 8 are closer to the air gap 9 of the electric motor than the holes 41 on the annular member 4, increasing the risk of unwanted cooling fluid flow in the air gap, which occurs through capillary action on the annular member. Furthermore, the longitudinal position of the holes 81 on the annular member 8 is substantially offset relative to the stator windings, making it impossible to optimize the cooling efficiency of the stator windings. Additionally, the annular member 8 does not provide a surface designed to guide the cooling fluid flowing from the holes 81 toward the stator windings.

[0083] Another difference between the invention of patent FR3059487 and the mechanism 10 according to the invention lies in the angular position of the hole 81 on the annular member 8 relative to the rotor windings; the hole 81 is arranged opposite the space separating the two rotor windings. Therefore, because the angular position of the hole 81 facilitates the movement of cooling fluid toward the space separating the two windings, the cooling fluid only partially cools the rotor windings. Conversely, the axial and angular positioning of the through-hole 41 of the mechanism 10 according to the invention improves and optimizes the cooling of the rotor 2 and stator 3. Specifically, the longitudinal position of the hole 41 on the annular member 4 is opposite the stator 3 bundle, which allows for optimization of the cooling efficiency of the stator 3 windings. Furthermore, the hole 41 on the annular member 4 is located at a distance from the air gap 9 of the electric motor, which greatly reduces the risk of unwanted cooling fluid flow in the air gap. Additionally, the annular member 4 includes a surface 4213 designed to guide the cooling fluid flowing from the hole 41 toward the stator windings. Furthermore, because the hole 41 is arranged opposite the middle region of the rotor windings, the angular position of the hole 41 on the annular member 4 relative to the rotor 2 windings is optimized. Therefore, the angular position of the hole 41 facilitates the movement of cooling fluid from one end of the rotor winding to the other.

[0084] Another consequence of the difference between the prior art annular member 8 and the annular member 4 of the mechanism according to the invention relates to the mechanical strength of the annular member. Cracks 82 have been observed around the hole 81, which are associated with deformation of the annular member caused by centrifugal force during operation of the electric motor incorporating the annular member 8. Computational simulations have demonstrated that the mechanical stress applied to the hole 81 of the prior art annular member 8 during operation of the electric motor is significantly greater than the mechanical stress applied to the hole 41 of the annular member 4 according to the invention. In particular, the mechanism of the hole 41 in the rounded portion 421 of the annular member 4 allows for a significant reduction in the mechanical stress applied to the hole 41. The results of computational simulations have demonstrated that the annular member 4 of the mechanism 10 according to the invention has mechanical strength characteristics that allow for an increase in motor speed of 1,000 revolutions per minute (corresponding to an increase in torque of approximately 15%) compared to the prior art annular member.

[0085] Furthermore, the method for manufacturing the ring-shaped part 4 according to the present invention is simplified compared to the method for manufacturing the ring-shaped part 8.

[0086] Finally, in the mechanism according to the invention, the positioning and shape of the cooling fluid discharge hole make it possible to improve the reliability of the rotor and increase the rotational speed of the rotor by reducing the mechanical stress applied around the hole.

[0087] Furthermore, the mechanism according to the invention allows for improved cooling of the rotor and stator, and thus improved operation of the cooling circuit of the electric motor, while reducing the flow rate of the pump in the cooling circuit. This reduction in pump flow rate reduces the cost of the cooling circuit and, on the other hand, improves the performance of the electric vehicle.

Claims

1. An institution (10) comprising • An electric motor (1) rotor (2), the rotor comprising - Rotor shaft (21), which extends along a first longitudinal axis (X1), and - A circular structure (22), arranged at one end of the rotor shaft (21) in a first plane (P1) perpendicular to the first axis (X1), the circular structure (22) including at least one tooth (221) of the rotor (2) and at least one wire winding (222) arranged around the at least one tooth (221), and • Ring-shaped member (4), which is attached to the circular structure (22) to enclose the circular structure (22). Its features are, The annular element (4) includes a set of through holes (41), each of which is arranged to intersect a radial plane (PR) containing the first longitudinal axis (X1) and passing through the center of a wire winding (222) arranged around the at least one tooth (221) to generate circulation of cooling fluid through the wire winding (222).

2. The mechanism as described in the preceding claim, characterized in that, The annular component (4) is able to hold the wire windings of the rotor (2) in the proper position.

3. The mechanism (10) as described in any one of the preceding claims, characterized in that, The through hole (41) is arranged at the rounded corner (421) of the annular member (4), which is located between the tubular portion (420) of the annular member (4) centered on the second longitudinal axis (X2) and the given surface (422) of the annular member (4) on the other hand, which is perpendicular to the second longitudinal axis (X2).

4. The mechanism (10) as described in the preceding claim, characterized in that, The annular component (4) includes - A first component (42), the first component comprising the tubular portion (420), the rounded corner (421), and the given surface (422), and - Second component (43), which is in particular in the form of a disc and fastened to a given surface (422) of the first component (42).

5. The mechanism (10) as claimed in the preceding claim, further comprising a stator (3) arranged around the annular member (4), characterized in that, The second component (43) provides a guiding surface (431) for cooling fluid flowing through the through hole (41) in the annular component (4) to orient the cooling fluid toward the wire winding (32) of the stator (3).

6. The mechanism as described in any one of the preceding claims, characterized in that, The through hole (41) in the annular member (4) is arranged to be traversed by a second plane (P2) perpendicular to the first longitudinal axis (X1), the second plane (P2) passing through the center of at least one wire winding (32) of the stator (3).

7. The mechanism as described in any one of the preceding claims, characterized in that, The arrangement includes at least one nozzle (6) designed to deliver cooling fluid to the vicinity of the winding (222) arranged around the at least one tooth (221), and The projection of one end (61) of the at least one nozzle (6) onto a third plane (P3) that passes through the through hole (41) and is perpendicular to the first longitudinal axis (X1) lies substantially on the straight line that connects the through hole (41) in the annular member (4) to the intersection (C2) between the third plane (P3) and the first longitudinal axis (X1).

8. The mechanism as described in any one of the preceding claims, characterized in that, Each through hole (41) in the annular member (4) has an oblong or oval shape, and / or the smaller dimension of each through hole (41) is measured along the second longitudinal axis (X2).

9. An electric motor comprising the mechanism as described in any one of the preceding claims.

10. A motor vehicle comprising the mechanism as described in any one of claims 1 to 8 or an electric motor as described in the preceding claim.

11. A method for manufacturing an annular member (4) of the mechanism (10) as described in any one of claims 4 to 8, characterized in that, The method includes: • Drilling through hole step (E1), that is, drilling through hole (41) in a given portion (421) of the first component (42) of the cylindrical workpiece intended to form the annular part (4), the given portion (421) being defined along the longitudinal axis (X1) of the cylindrical workpiece, then, • Stamping step (E2), that is, stamping the cylindrical workpiece so that the given portion (421) can be bent, thereby causing the given end (422) of the cylindrical workpiece to be located in a plane perpendicular to the longitudinal axis (X1) of the cylindrical workpiece, then • Fastening step (E3), namely, fastening the second part (43) of the annular member (4) to the given end (422).

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