End cover for rotary electric machine
By designing a regularly distributed axial and radial abutment surfaces on the end cover of the rotating motor, the problem of misalignment of the motor and reducer axis is solved, and the precise alignment and assembly accuracy is improved, and the rolling bearing damage is avoided.
Patent Information
- Application Number
- CN202380082334.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-10-13
- Filing Date
- 2023-10-11
- Publication Date
- 2025-07-08
AI Technical Summary
When coupling high-power reversible rotating motor and reduction element, the axis of the motor and reducer are not aligned, resulting in damage to the rolling bearing.
An end cover for a rotating electric machine is designed, including side walls and transverse walls, with regularly distributed axial and radial abutment surfaces on the side walls, and through openings and lugs are formed by mechanical processing to contact the reducer surface to ensure axis alignment.
Accurate alignment between the motor axis and the reducer axis is achieved, and damage to the rolling bearing caused by inaccurate alignment is avoided, the manufacturing process is simplified and assembly accuracy is improved.
Smart Images
Figure CN120283348A_ABST
Abstract
Description
Technical Field
[0001] The present invention particularly relates to an end cover for a rotating electric machine. Background Art
[0002] The present invention is particularly but not exclusively applicable to high-power reversible electric machines, which are capable of operating in alternator mode and motor mode, and are coupled to a reduction element.
[0003] In a manner known per se, a rotating electric machine has a stator and a rotor fixed to a shaft. The stator is mounted in a housing, which is configured to rotatably support the shaft on an end cover by means of rolling bearings.
[0004] The rotor has a body formed by a stack of laminations, which are held in a grouped form by a suitable fastening system. The rotor has magnetic poles formed, for example, by permanent magnets housed in cavities provided in the magnetic body of the rotor. Alternatively, in an architecture known as a "salient pole" structure, the magnetic poles are formed by coils wound around the arms of the rotor.
[0005] Furthermore, the stator has a body formed by a thin stack of laminations forming a ring, the inner face of which is provided with grooves opening inwards to receive windings. The windings are obtained, for example, from a continuous wire covered with enamel or from conductive elements in the form of hairpins interconnected by welding. The windings have phase windings connected in star or delta, the output terminals of which are connected to an electronic control module.
[0006] In the driveline of certain types of motor vehicles for transmitting mechanical power from an internal combustion engine to the wheels, a high-power reversible rotating electric machine can be coupled to a reduction element via a connection member. The reduction element can take the form of the vehicle's gearbox or the form of a speed reducer mounted on the vehicle's axle system and coupled to the rotating electric machine.
[0007] The rotating electric machine is capable of operating in alternator mode in order to supply energy, in particular, to the battery and to the vehicle's on-board network, and is capable of operating in motor mode in order to start the internal combustion engine and / or to supply power to the vehicle either alone or in combination with the internal combustion engine.
[0008] In order to provide a mechanical connection between the electric machine and the connection member coupled to the reduction element, a spline for coupling the shaft of the electric machine interacts with a complementary spline of the connection member. However, when coupling the electric machine and the speed reducer, misalignment of the axes of the connection member and the shaft of the electric machine can damage the electric machine when set to rotate, and in particular, damage the rolling bearings.
[0009] The object of the present invention is to make it possible to avoid the drawbacks of the prior art. Summary of the Invention
[0010] To this end, a subject of the present invention is an end cover for a rotating electric machine having an axis X, which includes a side wall and a transverse wall, the side wall including at least three adjacent surfaces, the adjacent surfaces being axial and regularly circumferentially distributed around the axis X, and each axial adjacent surface being intended to make surface contact with a flat surface of a speed reducer.
[0011] Thus, the present invention makes it possible to align the axis of the electric machine and the axis of the speed reduction element.
[0012] At least one axial adjacent surface is advantageously flat.
[0013] The side wall is advantageously provided with three lugs extending radially from the side wall, the three lugs being regularly distributed around the axis X, each lug having a radial adjacent surface perpendicular to the axis X, and each radial adjacent surface (170) being intended to make surface contact with another flat surface of the speed reducer.
[0014] Each lug advantageously includes a circular through-opening along X.
[0015] Each through-opening is radially aligned with the axial surface.
[0016] At least one lug further includes an oblong through-opening along X.
[0017] Another subject of the present invention is a motor vehicle assembly having a rotating electric machine and a speed reduction element, the rotating electric machine including a shaft, a rotor mounted on the shaft, a stator, in particular a stator surrounding the rotor, a front end cover as described in any one of the preceding claims, the front end cover having a rolling bearing for guiding the rotation of the shaft, the shaft having an end axially protruding relative to the rolling bearing, the end of the shaft being provided with splines, the speed reduction element being provided with a connecting member having complementary splines interacting with the splines of the end of the shaft so as to provide a mechanical connection between the shaft and the connecting member of the speed reducer, the speed reduction element being provided with a flat surface making surface contact with the adjacent surface of the end cover.
[0018] Another subject of the present invention is a method for manufacturing an end cover, wherein at least one adjacent surface is obtained by machining.
[0019] All adjacent surfaces can advantageously be obtained by a single pass of a machining tool.
[0020] In the case where the end cover is provided with through-openings, at least one opening can be obtained by a simple drilling operation.
[0021] Thus, the present invention makes it possible to obtain in a simple manner a positioning system for aligning the axis of the electric machine and the axis of the speed reducer. Description of the Drawings
[0022] The present invention will be better understood by reading the following detailed description of non - limiting exemplary embodiments of the invention and by studying the drawings.
[0023] Figure 1 Depicts a rotating electric machine according to the present invention.
[0024] Figure 2 Shows the electric machine and the speed reducer, as well as the adjacent surfaces of the speed reducer.
[0025] Figure 3 Shows the electric machine and the speed reducer, as well as the adjacent surfaces of the electric machine.
[0026] Figure 4a Shows the radial and axial adjacent surfaces of the end cover.
[0027] Figure 4b Is a contour map of the radial and axial adjacent surfaces on the wall of the end cover.
[0028] Figure 5a Shows the adjacent of the speed reducer on the end cover.
[0029] Figure 5b Shows the pin passing through the oblong hole of the bearing. Detailed Description
[0030] From one figure to another, the same, similar or like elements retain the same reference numerals. Moreover, the exemplary embodiments described below are in no way limiting.
[0031] In the following description, the front - rear orientation is considered to be Figure 1 the orientation from left to right in the
[0032] Thus, a "front" element should be understood as an element located on the side of the front rolling bearing 9a, while a "rear" element should be understood as an element located on the opposite side, i.e., on the side of the electronic control module 34.
[0033] Figure 1There is shown a rotating electrical machine 100 having a polyphase stator 1 surrounding a rotor 2 mounted on a shaft 3 having an axis X corresponding to the axis of the machine 100. The stator 1 surrounds the rotor 2 and there is a gap between the inner periphery of the stator 1 and the outer periphery of the rotor 2. The stator 1 is mounted in a housing 4 having a front end cover 5 and a rear end cover 6. The front end cover 5 and the rear end cover 6 each have a receiving portion 7, 8 for receiving respective rolling bearings 9a, 9b, and the rolling bearings 9a, 9b guide the rotation of the shaft 3 passing through the transverse wall 20 of the front end cover 5.
[0034] The stator 1 is mounted inside the front end cover 5, between the stator 1 and the side wall 15 of the front end cover 5.
[0035] The machine 100 is intended to be connected via a connection member 23 to a reduction element 22, the connection member 23 being visible Figure 2 therein.
[0036] The reduction element 22 can take the form of a motor vehicle gearbox or a speed reducer, which is mounted on the axle system of the vehicle and connected to the rotating electrical machine 100.
[0037] The machine 100 is capable of operating in alternator mode in order to supply energy in particular to a battery and to the on-board network of the vehicle, and is capable of operating in motor mode in order to start the internal combustion engine of the vehicle and, if appropriate, supply power to the vehicle either alone or in combination with the internal combustion engine. The power of the machine can for example be between 15 kW and 50 kW.
[0038] More specifically, the rotor 2 has a body 24 in the form of a stack of laminations. Permanent magnets 25 are mounted in cavities 26 in the body 24. The magnets 25 can be rare earth magnets or ferrite magnets, depending on the application and the desired power of the machine.
[0039] In addition, the rotor 2 has two bearings 28, 29, each of which bears against an axial end face of the rotor 2. These bearings 28, 29 axially hold the magnets and also serve to balance the rotor 2.
[0040] In addition, the stator 1 has a body 31 formed by a stack of laminations and a winding 32. The body 31 is formed by a stack of laminations which are held in a grouped form by a suitable fastening system (such as rivets).
[0041] The body of the stator 1 is provided with teeth which define slots for mounting the winding 32. The winding 32 has a set of phase windings which pass through the slots and form a bundle protruding on both sides of the body of the stator 1. In this case, the winding 32 is obtained from conductive elements in the form of hairpins connected to each other for example by welding. The winding 32 has phase windings of a double three-phase type with star connection and / or delta connection. The phase outputs are intended to be connected to an electronic control module 34.
[0042] The electronic control module 34 has a radiator, and in particular the power module 36 is fastened to this radiator, for example by means of screws. These power modules 36 incorporate switches in a manner known per se, said switches being in the form of MOS transistors for example, such that the phases of the rotating electric machine 100 can be controlled in motor mode or in alternator mode. The switching of these transistors is controlled by a control unit. The electronic control module 34 is mounted so as to bear against the rear face of the transverse wall of the rear end cover 6 via the radiator 35.
[0043] As Figure 3 shown, the front end 47 of the shaft 3 which projects axially with respect to the rolling bearing is provided with a spline 48, in which case the spline 48 has an axial orientation with respect to the axis X. The spline 48 at the end of the shaft 3 interacts with the complementary spline 49 of the connecting member 23, as Figure 2 shown. The spline 49 is formed in the inner circumference of the connecting member 23, has an annular shape and an axial orientation. Thus, the teeth of the splines 48, 49 of one of the elements enter the spaces separating the teeth of the splines 48, 49 of the other element and vice versa. This makes it possible to provide a mechanical rotary connection between the shaft 3 and the connecting member 23. The connecting member 23 is also rotatably connected to the reduction element 22, in particular by means of a spline connection.
[0044] The outer circumference of the side wall of the front end cover 5 includes three projections 16 which are regularly circumferentially distributed about the axis X, as Figure 3 shown. Thus, the three projections 16 extend from the outer circumference of the side wall such that three planes which contain the axis of the electric machine and intersect the side wall of the end cover (which are offset by 120° about the axis X) each intersect one of the projections 16. The advantage of having three projections instead of a ring around the entire circumference of the end cover is that at least the side wall 15 of the end cover is covered in order to optimize its cooling, in particular the air passage orifices provided in the wall of the end cover are not covered.
[0045] Each projection 16 has an axially adjacent surface 160, that is to say a surface which extends axially and is circumferential about the axis X, as Figure 4a shown. The axially adjacent surface 160 is advantageously planar. Since the circumferential extent of the surface is limited to a few millimeters, typically 8 mm, which is very small compared to the circumference of the end cover, this surface can be compared to a plane. The axial surfaces of the end cover are advantageously axially aligned, that is to say the plane which intersects one of the axial surfaces perpendicularly to the axis X intersects the other two axial surfaces.
[0046] The deceleration element further includes three planar axial surfaces 51 which are regularly circumferentially distributed about the axis of the connection member of the deceleration element. The three axial surfaces 51 are also axially aligned and equidistant radially from the axis X' of the connection member, such that when the end cover is assembled with the deceleration element, each axial abutment surface 160 of the end cover abuts against the axial surface 51 of the deceleration element. These abutment surfaces 160, 51 limit the radial clearance for alignment by using a centering stop for surface 51 formed by surface 160, such that the axis of the deceleration element X' can be aligned with the axis of the motor X. This eliminates the clearance resulting from using screws to mount the speed reducer on the end cover, which, as the sole means of aligning the axes, would lead to inaccurate alignment.
[0047] The end cover further includes three lugs 17 which extend radially from the side wall. The three lugs 17 are regularly circumferentially distributed about the axis X. Thus, the three lugs 17 extend from the outer periphery of the side wall 15 such that each of the three planes (which are offset by 120° about the axis X) containing the motor axis and intersecting the side wall of the end cover intersects one of the lugs.
[0048] Each lug 17 has a radial abutment surface 170 which is perpendicular to the axis X, as Figure 4a shown. The radial abutment surface is advantageously planar. These radial abutment surfaces are advantageously axially aligned, i.e., the plane containing one of the radial abutment surfaces also contains the other radial abutment surfaces. The deceleration element further includes three planar radial surfaces 52 which are regularly distributed about the axis X of the motor, equidistant radially from the axis and axially aligned.
[0049] Thus, during the assembly of the deceleration element with the motor, each radial abutment surface 170 abuts against the facing radial abutment surface 52 of the deceleration element in a planar manner. This abutment enables the axial alignment of the deceleration element and the motor. The axial and radial planar abutments are shown in Figure 5.
[0050] Each lug 17 advantageously has a circular through-opening 171, as Figure 4a shown, through which a nut for assembling the deceleration element with the motor passes. The through-opening 171 is advantageously located at the center of the radial abutment surface 170, which is advantageously circular.
[0051] In an advantageous embodiment, the axial and radial abutment surfaces are radially aligned, i.e., the plane containing the axis X of the motor and intersecting the projection 16 also intersects the through-opening 171. The proximity of the abutment surfaces makes them easier to machine, as described below. The proximity of the surfaces also enables minimizing the tolerance gaps between the axial and radial alignments of the axes X and X'. The axial abutment surfaces 51 and the radial abutment surfaces 52 of the deceleration element are also radially aligned along the three arms of the deceleration element, as Figure 2 shown.
[0052] The axial abutment surface 160 and the radial abutment surface 170 of the end cover are obtained by milling. The milling cutter for machining machined two radially aligned abutment surfaces 160 and 170 in a single pass of the machining tool over a sector typically of 30°. Then, the tool moves radially away from the end cover and then circumferentially around the axis of the electric machine in order to machine the next sector of the end cover.
[0053] The advantage of machining two aligned radial and perpendicular abutment surfaces in one pass is that it ensures good perpendicularity between these two reference surfaces because the workpiece does not move relative to the machining tool and thus there is no loss of reference.
[0054] After passing through the machining tool, the profile of the end cover in the plane containing the axis X and intersecting the projection 16 and the hole 171 is as Figure 4b shown. The radially abutting surface lies in the same plane as the radial surface 180 of the projection 16. Since the milling sweeps over the projection and the lug at the same axial height, the projection 16 has a ridge 18. The excessive thickness of the lug on which the abutment surface 170 extends allows any interference between the electric machine and the speed reducer to be avoided by the distance D shown in Figure 5a .
[0055] The lug 17 advantageously includes an oblong opening 19 which receives the Figure 5b assembly pin 19a shown in order to ensure the angular positioning of the assembly relative to the electric machine.
[0056] The circular hole 171 and the oblong opening 19 are advantageously obtained by a simple drilling operation without precise sizing. This is possible because a very precise alignment has already been obtained by using the abutment surfaces 160, 170. These assembly openings and angular alignment openings are very easily manufactured by a simple drilling operation.
Claims
1. An end cover (5) for a rotating electric machine having an axis X, comprising a side wall (15) and a transverse wall (20), The side wall (15) comprises at least three adjacent surfaces (160), The adjacent surfaces (160) are axial and are regularly circumferentially distributed around the axis X, Each axial adjacent surface (160) is intended to make surface contact with a flat surface of a speed reducer.
2. The end cover according to claim 1, wherein, At least one axial adjacent surface (160) is flat.
3. The end cover according to any one of claims 1 and 2, wherein, The side wall (15) is provided with three lugs (17) extending radially from the side wall (15), The three lugs (17) are regularly distributed around the axis X, Each lug (17) has a radial adjacent surface (170) perpendicular to the axis X, Each radial adjacent surface (170) is intended to make surface contact with another flat surface of a speed reducer.
4. The end cover according to claim 3, wherein, Each lug includes a circular through-opening (171) along X.
5. The end cover according to claim 4, wherein, Each through-opening (171) is radially aligned with an axial surface (160).
6. The end cover according to any one of claims 3 to 5, wherein, At least one lug (17) further includes an oblong through-opening (19) along X.
7. A motor vehicle assembly having: - a rotating electric machine (100), comprising a shaft (3), a rotor (2) mounted on the shaft, and a stator (1), in particular a stator (1) surrounding the rotor, - a front end cover (5) as claimed in any one of the preceding claims, having rolling bearings (9a, 9b) guiding the rotation of the shaft, - the shaft (3) has an end axially protruding relative to the rolling bearings, the end of the shaft being provided with a spline (48), and - a speed reduction element (22), the speed reduction element (22) being provided with a connecting member (23), the connecting member (23) having complementary splines (49) interacting with the splines (48) at the end of the shaft so as to provide a mechanical connection between the shaft and the connecting member of the speed reducer, The speed reduction element is provided with flat surfaces (51, 52) making surface contact with the adjacent surfaces (160, 170) of the end cover.
8. A method for manufacturing an end cap as claimed in any one of claims 1 to 6, wherein, At least one adjacent surface is obtained by machining.
9. The method according to claim 8, wherein, All the adjacent surfaces are obtained by a single pass of a machining tool.
10. The method according to any one of claims 8 and 9, wherein, In the case of an end cover provided with through-openings, at least one opening is obtained by a simple drilling operation.