Electric motor having a laminated core between two end discs

Abstract

The invention relates to an electric motor having a laminated core between two end discs, said electric motor having a rotor which has a rotor shaft and an active part plugged onto the rotor shaft, in particular a shrunk active part. The active part has the laminated core, and vanes which protrude radially with respect to the rotational axis of the rotor are formed on each end disc, in particular on the radially outer circumference of each end disc.

Description

[0001] Electric motor with a laminated core arranged between two end plates

[0002] Description:

[0003] The invention relates to an electric motor with a laminated core arranged between two end plates.

[0004] It is generally known that the use of a laminated core made up of individual laminations in an electric motor has manufacturing advantages over a core manufactured in another way and / or reduces power losses.

[0005] The invention is therefore based on the object of developing an energy-efficient electric motor.

[0006] According to the invention, the object is achieved in the electric motor according to the features specified in claim 1.

[0007] Important features of the invention in the electric motor are that the electric motor is provided with a laminated core arranged between two end plates, wherein the electric motor has a rotor which has a rotor shaft and an active part which is plugged onto the rotor shaft, in particular shrunk onto it, wherein the active part has the laminated core, wherein radially projecting vanes are formed on the respective end plate, in particular on the radially outer circumference of the respective end plate, relative to the axis of rotation of the rotor, to form an air flow within the motor.

[0008] The advantage here is that the electric motor is designed to be more energy efficient because power losses are reduced through improved cooling, allowing the electric motor to generate high drive power despite its compact size. This is because the end plates compress and stabilize the laminated core of the active part of the rotor. Without additional effort, a large number of blades can be provided in the raw casting of each end plate, which cause the end plate to also function as a radial fan when the rotor rotates. The air flow is therefore generated axially at the end of the laminated core and is thus arranged in the axial area covered by the winding overhang or at least in the axial area covered by the winding wires protruding axially from the laminated core. The air flow generated by the blades of the end plate therefore flows around the areas of the stator winding wires protruding from the laminated core, thus contributing to their cooling.This reduces the stator temperature and, consequently, its power losses. The heat is dissipated more effectively within the electric motor's interior by the airflow and dissipated into the environment through adjacent components, such as flanges.

[0009] In an advantageous embodiment, the blades of each end plate generate and / or convey a radially outward airflow, particularly during rotation of the rotor. This is advantageous because no separate fan wheel is required; instead, the end plate, in addition to its mechanical function of holding the laminated core together, also has the additional function of generating an airflow.

[0010] In an advantageous embodiment, the electric motor has a stator core, from which winding wires of a stator winding of the electric motor protrude axially and form a winding head. The air flow flows around the areas of the winding wires protruding axially from the stator core, particularly between the winding head and the stator core. Advantageously, the winding wires are made of copper, thus quickly dissipating heat.

[0011] In an advantageous embodiment, the air flow, particularly after flowing around the winding wires of the stator winding, flows through an air gap between the winding overhang and a motor housing of the electric motor that accommodates the stator laminated core. This advantageously involves flowing around the winding overhang, and the heat from the air flow can be dissipated to the motor housing. In an advantageous embodiment, the air flow flows around the winding overhang, particularly axially and radially, particularly in the axial and radial directions. This advantageously involves flowing around the winding overhang, and the heat from the air flow can be dissipated to the motor housing.

[0012] In an advantageous embodiment, the respective end plate is shaped such that it protrudes axially from the laminated core in a monotonically increasing manner with increasing radial distance relative to the axis of rotation of the rotor, in particular so that the laminated core is pressed more strongly and / or more tightly against the laminated core at a first radial distance than at a second radial distance, wherein the first radial distance is greater than the second radial distance. It is advantageous in this case that the end face of the end plate facing the laminated core is conical or stepped conical. Thus, when pressed against the laminated core, the radially outer edge of the end plate comes into contact with the laminated core before the region of the end face of the end plate lying further radially inward comes into contact with the laminated core, and the connection between the end plate and the laminated core is sealed radially outwards with a high degree of protection.The resulting, particularly hollow, active part is then placed onto the rotor shaft, and the resulting rotor can then be mounted on a machining center and machined. The maximum outer diameter of the rotor is achieved by a cutting tool, particularly by removing any radially projecting portion. The tool is preferably a turning tool or other chip-forming turning tool. The cooling lubricant used during this machining process is prevented from penetrating the active part by the aforementioned seal between the end plate and the laminated core.

[0013] Preferably, the end plate also protrudes axially towards the laminated core at its radially inner end region so that an additional seal can be achieved radially inward.

[0014] In an advantageous embodiment, the laminated core is held together by clamps extending in the axial direction. The advantage here is that the manufacturing aid can remain in the electric motor. Furthermore, an air duct is provided parallel to the clamps, which can also be used for heat transport. In an advantageous embodiment, air ducts extending in the axial direction through the laminated core open axially on both sides into a respective free space arranged between the laminated core and the respective winding head, in particular through which the air flow conveyed by the blades flows, especially during rotation of the rotor. The advantage here is that heat dissipation is further improved and thus also efficiency.

[0015] In an advantageous embodiment, the respective end plate has a perforated disc-shaped base body on which an axially projecting annular region is formed. It is advantageous that axial bores can be introduced into the annular region, particularly to facilitate rotor balancing.

[0016] In an advantageous design, the perforated disc-shaped base body projects radially beyond the ring area as a radially protruding collar area. The advantage here is that the collar area is capable of compressing the largest possible sheet stack. This allows the end plate to be designed with minimal material consumption.

[0017] In an advantageous embodiment, the vanes protrude radially from the annular region and are each connected to the radially protruding collar region, in particular wherein the vanes are arranged radially outside the annular region and / or axially adjacent to the radially protruding collar region. Advantageously, the vanes have a high circumferential speed and thus generate a strong airflow.

[0018] In an advantageous embodiment, the perforated disk-shaped base body has an annular thickened region radially within the annular region, which protrudes axially and / or has an axially thicker wall thickness than in the region of the perforated disk-shaped base body that is directly adjacent to the thickened region. The advantage here is that high forces can be introduced via long screws. In an advantageous embodiment, at least two recesses, in particular diametrically opposed, interrupt the thickened region in the circumferential direction and / or extend axially continuously through the perforated disk-shaped base body. The advantage here is that the rotational position of the end plate is positively identified.

[0019] In an advantageous embodiment, the recesses in the first of the two end plates are each formed as a cylindrical bore, while in the second of the two end plates, the recesses are each formed as a threaded bore. In particular, the two end plates are otherwise structurally identical to one another, with the exception of the design of their recesses as cylindrical bores or threaded bores. This is advantageous because the same raw casting can be used for both end plates, thus requiring a small number of components.

[0020] In an advantageous embodiment, stiffening ribs are connected to both the annular region and the perforated disk-shaped base body, in particular with the stiffening ribs arranged radially inside the vanes, particularly relative to the rotor's axis of rotation. This is advantageous because the end plate can be designed with minimal material while still being able to transmit high forces.

[0021] In an advantageous embodiment, the blades are evenly spaced from each other in the circumferential direction. This is advantageous in that a uniform airflow is generated.

[0022] In an advantageous embodiment, the stiffening ribs are evenly spaced from one another in the circumferential direction. This is advantageous because a uniform force distribution can be achieved in the circumferential direction.

[0023] In an advantageous embodiment, the vanes are evenly spaced from one another in the circumferential direction by a respective first circumferential angle, with the stiffening ribs being evenly spaced from one another in the circumferential direction by a respective second circumferential angle, the first circumferential angle being different from the second circumferential angle. This is advantageous in that the end plate can be designed to save material, in particular with thin walls, while still reducing resonant vibrations. This is because no particular vibration modes can develop in the circumferential direction if the number of stiffening ribs and the number of vanes are relatively prime to one another. Prime numbers are preferably used as the numbers.

[0024] In an advantageous embodiment, long screws spaced apart from one another in the circumferential direction extend axially through the laminated core and the cylindrical bore of the first of the two end plates, with a respective threaded portion of the long screws being screwed into a respective threaded portion of the second of the two end plates. The advantage here is that the identically constructed raw material can be used to manufacture the end plates.

[0025] Further advantages emerge from the dependent claims. The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art.

[0026] The invention will now be explained in more detail using schematic illustrations:

[0027] Figure 1 shows an electric motor according to the invention in a sectioned oblique view.

[0028] Figure 2 shows a sectional view of the rotor of the electric motor.

[0029] Figure 3 shows an enlarged view of a first area of ​​Figure 2.

[0030] Figure 4 shows an enlarged view of a second area of ​​Figure 2.

[0031] Figure 5 shows a sectioned oblique view of the rotor of the electric motor.

[0032] Figure 6 shows an end plate 1 of a rotor lamination stack in an oblique view.

[0033] As shown in the figures, the electric motor has an active part 4 with a laminated core, which is plugged, in particular shrunk, onto a rotor shaft 2 rotatably mounted in the electric motor.

[0034] When the electric motor is designed as an asynchronous motor, the active part 4 is additionally provided with a squirrel cage made of aluminum and / or copper wires; when designed as a synchronous motor, the active part 4 is additionally equipped with permanent magnets, and when designed as a synchronous reluctance motor, the active part 4 has the laminated core, in particular without permanent magnets and without a squirrel cage.

[0035] The electric motor has a motor housing 9, in particular with cooling fins. This motor housing 9 surrounds the stator laminated core 5, in which the stator winding is inserted, wherein the winding overhang 8, in particular the deflection area of ​​the stator winding wires, is deflected, protruding axially on both sides from the area covered by the stator laminated core 5 in the axial direction. In this case, winding wires of the stator winding initially lead axially essentially straight out of the stator laminated core 5 and are bent around in the area of ​​the winding overhang 8, before being deflected approximately 180° and leading back into the stator laminated core. Therefore, between the winding overhang 8 and the stator laminated core 4 there is a narrow air space that opens into an air gap arranged radially between the winding overhang 8 and the motor housing 9.

[0036] The rotor core 4 is axially limited on both sides by a respective end plate 1.

[0037] The axial direction is parallel to the rotor shaft's rotational axis. The circumferential direction is related to the rotor shaft's rotational axis, and the radial direction is also related to the rotor shaft's rotational axis.

[0038] This end plate 1 has on its radially outer circumference wings 7 which extend in the radial and axial direction and are in particular evenly spaced from one another in the circumferential direction.

[0039] When the end plate 1 rotates, the vanes 7 convey a radial air flow, which thus flows into the narrow air space and flows radially around the stator winding wires. The air flow then flows further in the axial direction through the air gap between the winding head 8 and the motor housing 9 and then flows along a housing part (not shown in the figures), in particular the bearing flange or bearing plate, of the electric motor, until it is again drawn in radially within the winding head by the vanes 7. A bearing for supporting the rotor is preferably accommodated in the housing part.

[0040] The air flow conveyed by the vanes 7 thus contributes to the heat spreading in the motor interior, since it transports the heat from the winding wires to the inside of the motor housing 9 and to the inside of the housing part, from where the heat is then dissipated to the environment.

[0041] The stator laminated core 5 is held together by clamps 6, which extend in the axial direction along the stator laminated core 5. Air ducts are formed next to the clamps 6, which also extend in the axial direction. A portion of the air flow conveyed by the vanes 7 can also be conveyed through these air ducts, so that an improved cooling effect can be achieved. The end plates 1, arranged axially on both sides, are made from the same blank and differ only in the specific design of through-holes 64, which are designed as threaded holes in the first of the two end plates 1 and as cylindrical bores in the second of the two end plates 1.

[0042] Long screws 3 extend axially through the two end plates 1 and the laminated core 4, and their threaded portions are screwed into the threaded holes of the first of the two end plates 1, while they extend through the cylindrical holes of the second of the two end plates 1. Furthermore, the screw heads of the long screws 3 rest against the second of the two end plates 1.

[0043] By screwing in the long screws 3, the end plates 1 press the laminated core 4 together on both sides.

[0044] As shown in Figures 3 and 4, the end plate 1 protrudes axially towards the laminated core in its radially outer region, so that when the laminated core 4 is compressed, this radially outer region presses against the laminated core first and only later the radially further inner region. The advantage here is that the end plates 1 are connected as tightly as possible to the laminated core 4, particularly in the radially outer region, and thus the rotor can be over-rotated after being compressed. For this purpose, the rotor is picked up in a machine tool and over-rotated by a tool, in particular a turning tool, in particular limited to a maximum radial distance relative to the rotational axis of the rotor. This is because deformations resulting from compression must not protrude into the annular gap between the laminated core 4 and the stator laminated core 5, because a minimum radial width of the annular gap must be maintained.

[0045] This turning operation uses coolant. However, since the rotor is sealed as described above, penetration of the coolant into the rotor is prevented.

[0046] Furthermore, an axially directed bore 50, in particular a blind bore, is formed in each end plate 1, thereby enabling balancing. The end plate 1 has a perforated-disk-shaped base body 66, which has an annular thickened region 62 at its radially inner end region, the axial wall thickness of which is greater than the axial wall thickness of the remaining perforated-disk-shaped base body 66.

[0047] A ring region 61, which is radially spaced from the thickened region 62, projects axially on the perforated disc-shaped base body 66.

[0048] The perforated disc-shaped base body 66 protrudes radially beyond the annular region 61 as a radially protruding collar region 63. The vanes 7 are connected to both the annular region 61 and the radially protruding collar region 63 and protrude radially from the annular region 61.

[0049] Stiffening ribs 60 are connected to both the perforated disc-shaped base body 66 and the ring area 61.

[0050] Preferably, the radially projecting collar region 63 is arranged within the axial region which is covered by the remaining perforated disc-shaped base body in the axial direction.

[0051] The annular thickened area 62 is interrupted by recesses 65, which are diametrically opposed and arranged at the same axial and radial position. In the area of ​​the recesses 65, the end plate 1 has a reduced wall thickness, i.e., a smaller wall thickness than in the area surrounding the respective recess 65. One of the bores 64 is provided in each of these thinned areas. The recesses 65 are useful for adjusting the angular position of the end plate 1.

[0052] In total, up to four bores 64 spaced apart from one another in the circumferential direction are preferably made in the end plate 1.

[0053] In the radial direction, the vanes 7 do not protrude beyond the radially projecting collar region 63. In further embodiments according to the invention, the balancing bores 50 are not axially but radially inserted, in particular in the radially projecting collar region 63.

[0054] List of reference symbols

[0055] 1 end plate

[0056] 2 rotor shaft

[0057] 3 long screw

[0058] 4 Active part with laminated core

[0059] 5 Stator laminated core

[0060] 6 clamps and axial air duct

[0061] 7 wings

[0062] 8 Winding head of the stator winding

[0063] 9 Engine housing, especially with cooling fins

[0064] 50 Drilling, especially blind holes

[0065] 60 stiffening ribs

[0066] 61 ring area

[0067] 62 annular thickening area

[0068] 63 radially protruding collar area

[0069] 64 bore

[0070] 65 Recess in the annular thickening area 62

[0071] 66 perforated disc-shaped base body

Claims

Patent claims:

1. Electric motor with a laminated core arranged between two end plates, the electric motor having a rotor which has a rotor shaft and an active part which is plugged onto the rotor shaft, in particular shrunk onto it, the active part having the laminated core, characterized in that radially projecting vanes are formed on the respective end plate, in particular on the radially outer circumference of the respective end plate, with respect to the axis of rotation of the rotor, in particular for forming an air flow within the motor, in particular wherein the laminated core is axially delimited on both sides by the two end plates.

2. Electric motor according to claim 1, characterized in that a radially outward flowing air stream is generated and / or conveyed by the vanes of a respective end plate, in particular during rotational movement of the rotor.

3. Electric motor according to one of the preceding claims, characterized in that the electric motor has a stator core, from which winding wires of a stator winding of the electric motor project axially and form a winding head, wherein the air flow flows around regions of the winding wires projecting axially from the stator core, in particular between the winding head and the stator core.

4. Electric motor according to one of the preceding claims, characterized in that the air flow, in particular after flowing around the winding wires of the stator winding, flows through an air gap between the winding head and a motor housing of the electric motor receiving the stator laminated core and / or that the air flow flows around the winding head, in particular axially and radially, in particular in the axial and radial direction.

5. Electric motor according to one of the preceding claims, characterized in that the respective end plate is shaped such that it protrudes monotonically increasingly axially from the laminated core with increasing radial distance relative to the axis of rotation of the rotor, in particular so that the laminated core is pressed more strongly and / or more densely against the laminated core at a first radial distance than at a second radial distance, wherein the first radial distance is greater than the second radial distance.

6. Electric motor according to one of the preceding claims, characterized in that the laminated core can be held together by clamps extending in the axial direction, and / or that air ducts extending in the axial direction through the laminated core open axially on both sides into a respective free space arranged between the laminated core and the respective winding head, in particular which is flowed through by the air flow conveyed by the blades, in particular during rotational movement of the rotor.

7. Electric motor according to one of the preceding claims, characterized in that the respective end plate (1) has a perforated plate-shaped base body (66) on which an axially projecting annular region (61) is formed.

8. Electric motor according to one of the preceding claims, characterized in that the perforated disc-shaped base body (66) projects beyond the annular region (61) in the radial direction as a radially projecting collar region (63), and / or that the vanes project radially on the annular region (61) and are each connected to the radially projecting collar region (63), in particular wherein the vanes (7) are arranged radially outside the annular region (61) and / or are arranged axially next to the radially projecting collar region (63).

9. Electric motor according to one of the preceding claims, characterized in that radially within the annular region, the perforated disc-shaped base body (66) has an annular thickening region (62) which projects axially and / or has an axially thicker wall thickness than in the region of the perforated disc-shaped base body (66) which adjoins the thickening region (62), in particular directly.

10. Electric motor according to one of the preceding claims, characterized in that at least two, in particular diametrically opposed, recesses interrupt the thickened region in the circumferential direction and / or are formed axially continuously through the perforated disc-shaped base body (66).

11. Electric motor according to one of the preceding claims, characterized in that in the first of the two end plates the recesses are each designed as a cylindrical bore, wherein in the second of the two end plates the recesses are each designed as a threaded bore, in particular wherein the two end plates are otherwise constructed identically to one another, i.e. with the exception of the design of their recesses as cylindrical bores or threaded bores.

12. Electric motor according to one of the preceding claims, characterized in that Stiffening ribs are connected both to the ring region (61) and to the perforated disc-shaped base body, in particular wherein the stiffening ribs are arranged radially inside the vanes, in particular with respect to the axis of rotation of the rotor.

13. Electric motor according to one of the preceding claims, characterized in that the vanes are in particular evenly spaced from one another in the circumferential direction and / or that the stiffening ribs are in particular evenly spaced from one another in the circumferential direction.

14. Electric motor according to one of the preceding claims, characterized in that the vanes are spaced apart from one another in the circumferential direction evenly by a respective first circumferential angular amount, wherein the stiffening ribs are spaced apart from one another in the circumferential direction evenly by a respective second circumferential angular amount, the first circumferential angular amount being different from the second circumferential angular amount.

15. Electric motor according to one of the preceding claims, characterized in that elongated screws spaced apart from one another in the circumferential direction project in the axial direction through the laminated core and the cylindrical bore of the first of the two end plates, wherein a respective threaded region of the elongated screws is screwed into a respective threaded region of the second of the two end plates.

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