Rotary electric machine with damping and cooling stator sleeve

Abstract

The invention relates to a rotary electric machine (1) for a motor vehicle, comprising: a rotor (2) non-rotatably connected to a rotor shaft (9); a stator (3) surrounding the rotor (2); a housing (4) in which the rotor (2) and the stator (3) are enclosed, the rotor shaft (9) being rotatably mounted along an X-axis; a stator (3) carried by the housing (4); and a stator sleeve (5) arranged radially between the outer surface of the stator (3) and the inner cylindrical surface (8) of the housing (4); wherein the stator sleeve (5) is made of an elastic material and is arranged to filter vibrations generated by the stator (3) and caused by electromagnetic forces present in the stator (3) during operation of the rotary electric machine (1); and wherein the stator sleeve (5) comprises a cooling tank (15) intended to be connected to a coolant supply line.

Description

Technical Field

[0001] The present invention relates to the field of rotating electric machines for motor vehicles. Background Art

[0002] US2019 / 0305615 discloses a rotating electric machine including a rotor, a stator, and a housing, with the rotor and stator enclosed in the housing. The stator includes windings and a core, and the windings are inserted into the core. The stator is fixed to the housing by a stator sleeve radially disposed between the core and the housing. The stator sleeve includes cooling grooves arranged on the outer periphery of the stator sleeve. Thus, a flow path for coolant to flow is formed between the outer peripheral surface of the stator sleeve and the inner peripheral surface of the housing. Therefore, the stator sleeve has a heat dissipation function.

[0003] This rotating electric machine is not entirely satisfactory. When the rotating electric machine operates, the electromagnetic force present in the stator causes high vibration excitation of the entire housing. Therefore, high levels of noise and vibration are measured on the outer side of the housing. Summary of the Invention

[0004] Therefore, a basic concept of the present invention is to provide a rotating electric machine having good heat dissipation and vibration damping performance.

[0005] For this purpose, according to one embodiment, the present invention provides a rotating electric machine for a motor vehicle, comprising:

[0006] - a rotor non-rotatably connected to a rotor shaft,

[0007] - a stator surrounding the rotor;

[0008] - a housing in which the rotor and stator are enclosed, and the rotor shaft is rotatably mounted on the housing along the X-axis;

[0009] and

[0010] - a stator sleeve enclosed in the housing and radially disposed between the outer surface of the stator and the inner cylindrical surface of the housing;

[0011] wherein the stator sleeve is made of an elastic material and is arranged to filter vibrations generated by the stator and caused by the electromagnetic force present in the stator when the rotating electric machine operates; and

[0012] wherein the stator sleeve includes cooling grooves intended to be connected to a coolant supply line.

[0013] Therefore, such a stator sleeve has a dual function, namely suppressing vibrations and cooling the stator. This easily enables the rotating electric machine to have good heat dissipation and vibration damping performance.

[0014] According to an embodiment, such a rotating electrical machine may have one or more of the following features.

[0015] According to one embodiment, the cooling grooves are helical about the X-axis and arranged on the radially inner surface of the stator such that a flow path having a helical shape is formed between the radially inner surface of the stator sleeve and the outer surface of the stator. This further improves the heat dissipation performance of the stator sleeve.

[0016] According to one embodiment, the housing includes a supply port in communication with a first end of the cooling groove.

[0017] According to one embodiment, the coolant supply line is filled with a coolant that is a dielectric fluid, such as oil.

[0018] According to one embodiment, the elastic material is an elastomeric material, such as natural rubber or synthetic rubber.

[0019] This material has good vibration filtering performance and is also much lighter than aluminum, which is commonly used to manufacture the stator sleeve, thus reducing the weight of the entire rotating electrical machine.

[0020] According to one embodiment, the elastic material has a Young's modulus included between 0.001 GPa and 0.1 GPa.

[0021] According to one embodiment, the housing includes two opposing faces that are orthogonal to the X-axis and joined together by a cylindrical skirt extending about the X-axis.

[0022] According to one embodiment, the stator is connected to one of the two opposing faces of the housing by screw bolts, the screws extending parallel to the X-axis and each passing through a corresponding hole arranged in the stator.

[0023] According to one embodiment, the stator sleeve is pressed against at least one of the opposing faces of the housing.

[0024] According to one embodiment, the stator sleeve is pressed against each of the two opposing faces of the housing.

[0025] According to one embodiment, the housing includes at least two components, each component including a flange end, and the flange ends of the two components are attached to each other.

[0026] According to one embodiment, the stator sleeve includes a radial flange axially arranged between the two flange ends.

[0027] According to one embodiment, the stator sleeve includes a metal insert embedded in the elastic material.

[0028] According to one embodiment, the stator includes a winding and an iron core that carries the winding.

[0029] According to one embodiment, the iron core includes a plurality of pipes arranged to direct coolant from a coolant tank to the windings. This further improves the cooling performance.

[0030] According to one embodiment, the present invention also provides a motor vehicle including the above-described rotating electric machine. Description of the Drawings

[0031] The present invention will be better understood during the following description of several embodiments of the present invention given by way of illustration only and not by way of limitation with reference to the accompanying drawings, and its further objects, details, features and advantages will become clearer.

[0032] Figure 1 is a schematic cross-sectional view showing an electric rotating machine according to a first embodiment.

[0033] Figure 2 is a schematic cross-sectional view showing an electric rotating machine according to a second embodiment. Detailed Description

[0034] In the specification and claims, the terms "outer", "inner", and "axial" and "radial" orientations will be used to specify elements of the rotating electric machine according to the definitions given in the specification. By convention, the rotational axis X of the rotor of the rotating electric machine defines the "axial" orientation. The "radial" orientation is orthogonal to the axis X and extends away from the axis X from the inside towards the outside.

[0035] The rotating electric machine 1 is designed to equip a motor vehicle. The rotating electric machine 1 can be used as a motor to propel an electric vehicle or a hybrid vehicle and / or as a generator for such a vehicle. The rotating electric machine 1 can also be used in a motor vehicle having a thermal engine. In this case, the rotating electric machine 1 can be an alternator or an alternator-starter, the alternator being configured to convert mechanical energy from the thermal engine into electrical energy for the purpose of charging the vehicle battery and powering the vehicle's on-board network, and the alternator-starter also having an additional operating mode in which it converts electrical energy into mechanical energy to start the thermal engine of the motor vehicle.

[0036] As Figure 1 shown, the rotating electric machine 1 includes a rotor 2, a stator 3, and a housing 4, the rotor 2 and the stator 3 being enclosed in the housing 4. The housing 4 has a generally cylindrical shape and includes two opposing disk-shaped faces 6, 7 joined together by a cylindrical skirt 8. The housing 4 includes at least two components attached to each other. In the illustrated embodiment, the two components each include flange ends 11, 12, and the flange ends of the two components are attached to each other, for example, by bolts (not shown).

[0037] The rotor 2 is mounted in the housing 4 in a manner that enables it to rotate about the axis of rotation X. For this purpose, the rotor 2 is non-rotatably connected to a rotor shaft 9, which is rotatably mounted on the housing 4 along the X-axis. In Figure 1 the embodiment shown, the rotor shaft 9 is rotatably guided on the housing 4 by means of a pair of bearings 13, 14. In addition, the rotor shaft 9 passes through at least one hole in one of the disk-shaped faces 6 of the housing 4 to be coupled to another transmission component.

[0038] The stator 3 radially surrounds the rotor 2. The stator 3 includes an iron core that carries windings. The iron core is formed with a plurality of grooves, and the windings are inserted into the inner sides of the grooves. The iron core includes, for example, a plurality of plates, such as electrical steel sheets, which are laminated together and packed against each other to form a laminate.

[0039] The stator 3 is bolted to one of two opposite faces 6 of the housing 4 by means of screws 10, one of the screws 10 being shown in Figure 1 . The screws 10 extend parallel to the X-axis and each pass through a corresponding hole arranged in the stator 3, more specifically through a corresponding hole arranged in its iron core.

[0040] In addition, a stator sleeve 5 is radially interposed between the outer surface of the stator 3 and the inner cylindrical surface of the housing 4. In other words, the stator sleeve 5 includes a radially outer surface that contacts the cylindrical skirt of the housing and a radially inner surface that contacts the outer cylindrical surface of the stator 3.

[0041] As described below, the stator sleeve 5 has heat dissipation and vibration damping functions.

[0042] The stator sleeve 5 includes cooling grooves 15 arranged on its radially inner surface. The cooling grooves 15 are helical around the X-axis. As Figure 1 shown, in the state where the stator sleeve 5 is assembled to the outside of the stator 3, the openings of the cooling grooves 15 are blocked by the radially outer surface of the stator 3. Thus, a flow path 18 having a spiral shape is formed between the radially inner surface of the stator sleeve 5 and the outer surface of the stator 3. Compared with the prior art (i.e., when the cooling grooves 15 are provided between the inner cylindrical surface of the housing 4 and the radially outer surface of the stator sleeve 5), this arrangement has better heat dissipation performance.

[0043] In addition, the flow path 18 is on the one hand intended to be connected to a coolant supply line. For this purpose, the housing 4 includes a supply port 16, that is, a hole for supplying coolant to the cooling grooves 15. The supply port 16 communicates with the first end of the cooling grooves 15 through a first opening 19 formed in the stator sleeve 5.

[0044] The coolant is a dielectric fluid, such as oil, which allows the coolant to directly contact the iron core of the stator 3.

[0045] Furthermore, according to an embodiment not shown, the iron core further includes a plurality of pipes arranged to guide coolant from the coolant tank 15 to the windings of the stator 3.

[0046] The housing 4 includes at least one discharge port 17, i.e., a hole for discharging the coolant flowing in the housing 4.

[0047] The stator sleeve 5 is made of an elastic material and thus has vibration damping characteristics. Therefore, the stator sleeve 5 is arranged to filter the vibrations of the stator 3 caused by the electromagnetic forces present in the stator 3 during operation. Thus, the stator sleeve 5 limits the propagation of vibrations from the stator 3 towards the housing 4 of the rotating electric machine 1 to reduce the magnetic noise of the rotating electric machine 1.

[0048] The stator sleeve 5 is made of a material having a Young's modulus between 0.001 GPa and 0.1 GPa.

[0049] The stator sleeve 5 is advantageously made of an elastomeric material, such as rubber.

[0050] In Figure 1 the embodiment of, the stator sleeve 5 further includes a metal insert 21 embedded in the elastomeric material. If necessary, such a metal insert 21 can be used to increase the stiffness of the stator sleeve 5 and / or ensure its tightness.

[0051] Figure 2 A rotating electric machine according to a second embodiment is shown. This second embodiment differs from the first embodiment described above with respect to Figure 1 in that the stator sleeve 5 is pressed against at least one of the disc-shaped surfaces 7, 8 of the housing 4 and advantageously against both disc-shaped surfaces 7, 8 of the housing 4. Furthermore, the stator sleeve 5 further includes a radial flange 22 that is axially interposed between the two flange ends 11, 12 of two components of the housing 4 that are attached to each other. These features further improve the vibration damping performance of the stator sleeve 5.

[0052] Although the invention has been described in connection with several embodiments, it is quite clear that the invention is in no way limited thereto, and the invention includes all technical equivalents of the described devices and their combinations, if these fall within the scope of the invention claimed.

[0053] The use of the verbs "have", "contain" or "include" and their conjugations does not exclude the presence of elements or steps other than those recited in the claims.

[0054] In the claims, any reference signs in parentheses shall not be construed as limiting the claim.

Claims

1. A rotating electric machine (1) for a motor vehicle, comprising: - a rotor (2) non-rotatably connected to a rotor shaft (9), - a stator (3) surrounding said rotor (2); - a housing (4) in which said rotor (2) and said stator (3) are enclosed, and said rotor shaft (9) is rotatably mounted on said housing (4) along the X axis; and - a stator sleeve (5) enclosed in said housing (4) and radially arranged between the outer surface of said stator (3) and the inner cylindrical surface of said housing (4); characterized in that said stator sleeve (5) is made of an elastic material and is arranged to filter vibrations generated by said stator (3) and caused by electromagnetic forces present in said stator (3) when the rotating electric machine (1) is operating, and said stator sleeve (5) includes cooling grooves (15) intended to be connected to a coolant supply line.

2. The rotating electrical machine (1) according to claim 1, wherein, Said cooling grooves (15) are helical around the X axis and are arranged on the radially inner surface of said stator sleeve (5) such that a flow path (18) having a helical shape is formed between the radially inner surface of said stator sleeve (5) and the outer surface of said stator (3).

3. The rotating electrical machine (1) according to claim 1 or 2, wherein, Said housing (4) includes a supply port (16) communicating with a first end of said cooling grooves (15).

4. The rotating electrical machine (1) according to any one of claims 1 to 3, wherein, Said coolant supply line is filled with a coolant which is a dielectric fluid such as oil.

5. The rotating electrical machine (1) according to any one of claims 1 to 4, wherein, Said elastic material is an elastomeric material.

6. The rotating electrical machine (1) according to any one of claims 1 to 5, wherein, Said elastic material has a Young's modulus between 0.001 GPa and 0.1 GPa.

7. The rotating electrical machine (1) according to any one of claims 1 to 6, wherein, Said housing (4) includes two opposite faces (6, 7) orthogonal to the X axis and joined together by a cylindrical skirt (8) extending around the X axis.

8. The rotating electrical machine (1) according to claim 7, wherein, Said stator (3) is bolted to one of said two opposite faces (6, 7) of said housing (4) by means of screws (10) extending parallel to the X axis and each passing through a corresponding hole arranged in said stator (3).

9. The rotating electrical machine (1) according to claim 7 or 8, wherein, Said stator sleeve (5) is pressed against at least one of said opposite faces (7, 8) of said housing (4).

10. The rotating electrical machine (1) according to any one of claims 7 to 9, wherein, Said housing (4) includes at least two components each including flange ends (11, 12), said flange ends (11, 12) of said two components being attached to each other, and wherein said stator sleeve (5) includes a radial flange (22) axially arranged between said two flange ends (11, 12).

11. The rotating electrical machine (1) according to any one of claims 1 to 10, wherein, Said stator sleeve (5) includes a metal insert (21) embedded in said elastic material.

12. The rotating electrical machine (1) according to any one of claims 1 to 11, wherein, Said stator (3) includes a winding and an iron core carrying said winding.

13. The rotating electrical machine (1) according to the combination of claims 2 and 12, wherein, Said iron core includes a plurality of ducts arranged to direct coolant from said cooling grooves (15) to said winding.

14. A motor vehicle comprising a rotating electric machine (1) according to any one of claims 1 to 13.

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