ELECTRIC MOTOR WITH ROTOR SHAFT AND SHEET METAL PACK

Description

[0001] The invention relates to an electric motor with a rotor shaft and laminated core.

[0002] From EP 3788701 A1 a single sheet of a rotor with slot groups for forming reluctance poles is known.

[0003] From the EP 3 413 439 A1 is a rotor of an electric motor.

[0004] From the US 2019 / 0 229 568 A1 A synchronous reluctance motor is known.

[0005] From the US 2015 / 0 162 788 A1 is a rotor for a reluctance motor.

[0006] From the JP 2009 - 77 458 A A laminated rotor of a reluctance motor is known.

[0007] From the JP 2003 - 52 186 A A method for operating a reluctance motor is known.

[0008] From the US 2019 / 0 238 035 A1 A synchronous reluctance motor is known.

[0009] From the CN 1 12 671 127 A A rotor lamination for a reluctance motor is known.

[0010] From the JP 2011 - 193 627 A is a rotor of an electric motor.

[0011] From the EP 3 672 026 A1 Asynchronous starting of a synchronous reluctance motor is known.

[0012] From the JP 2003 - 259 615 A A reluctance motor is known.

[0013] From theWO 2018 / 083 639 A1 A self-starting synchronous reluctance motor is known.

[0014] From the GB 940 997 A The most readily available state of the art is an electric motor.

[0015] From the US 2017 / 179801 A1 A reluctance rotor is known.

[0016] From the CN 210 608 876 U is known as the rotor of an electric motor.

[0017] The invention is therefore based on the objective of further developing an electric motor with rotor shaft and laminated core, whereby simple operation should be achievable.

[0018] According to the invention, the problem is solved in the electric motor with rotor shaft and laminated core according to the features specified in claim 1.

[0019] Key features of the invention for the electric motor with rotor shaft and laminated core are, that the laminated core is mounted on the rotor shaft, wherein the laminated core, in particular on its radially outer circumference with respect to the axis of rotation of the rotor shaft, has grooves spaced uniformly apart in the circumferential direction for receiving short-circuit bars of a squirrel-cage cage, wherein the laminated core, in particular for forming reluctance poles, has groups of slots spaced regularly apart from each other in the circumferential direction with respect to the axis of rotation of the rotor shaft, wherein each group of slots has at least three slots, wherein each slot is circular arc-shaped or elliptical arc-shaped, wherein the slots of a respective group of slots are aligned concentrically to each other.

[0020] An advantage of this is that reluctance poles can be formed easily. This is because the design of the slots according to the invention allows for the equalization of the reluctance poles, resulting in a more uniform, and therefore more consistent, torque distribution during rotational movement.

[0021] In a preferred configuration, the number of slot groups is four. An advantage of this is that grid-synchronous operation is possible with minimal effort.

[0022] In an advantageous embodiment, with respect to the center point, in particular the center of the circle, of the circle containing the respective circular arc, each slot is bounded radially inwards by a first circular arc and radially outwards by a second circular arc. The advantage here is that the most efficient possible field layout can be achieved within the sheet metal stack.

[0023] In an advantageous embodiment, all circles containing the arcs of all slots have the same, in particular the same and / or identical, center point, especially the center of a circle, the center of an ellipse, or the focal point of an ellipse, and are therefore arranged concentrically to one another. It is advantageous that a reluctance pole can be strongly pronounced.

[0024] According to the invention is the radial extent of the respective slot relative to the center point, in particular the center of a circle, the center of an ellipse or the focal point of an ellipse. in the circumferential direction around the center point, in particular the center of a circle, the center of an ellipse or the focal point of an ellipse, constant and / or independent of the circumferential angle around the center point, in particular the center of a circle, the center of an ellipse or the focal point of an ellipse.

[0025] The advantage here is that efficient field management is possible.

[0026] In an advantageous embodiment, the radial extent of the respective slot, relative to the center point (in particular the center of a circle, center of an ellipse, or focal point of an ellipse), increases with increasing radial distance from the center point (in particular the center of a circle, center of an ellipse, or focal point of an ellipse). It is advantageous that the field lines can be bundled, thus enabling the formation of a highly effective reluctance pole.

[0027] According to the invention The radial distance between any two nearest slits of a slit group, relative to the center point (in particular the center of a circle, center of an ellipse, or focus of an ellipse), increases with increasing distance from the center point (in particular the center of a circle, center of an ellipse, or focus of an ellipse). This is advantageous because it enables efficient field guidance. 1

[0028] In an advantageous embodiment, each slot is spaced at its respective end, whether oriented against or in the circumferential direction, from one of the grooves by a minimum distance, wherein the value of the minimum distance is the same for all ends of all slots, in particular, it is identical. This is advantageous because it enables efficient field guidance.

[0029] According to the invention A short-circuit cage is designed with the sheet metal stack as a composite part.

[0030] The advantage here is that cost-effective production is possible.

[0031] In an advantageous embodiment, the stator of the electric motor has a three-phase winding. The advantage here is that the electric motor can be operated as an asynchronous motor and yet still enables grid-synchronous operation due to the reluctance properties of the motor generated by the reluctance poles.

[0032] In an advantageous embodiment, the slot groups are identical to one another, and in particular, can be aligned with each other by rotation about the axis of rotation of the rotor shaft. This is advantageous because it enables low-vibration and low-sway operation.

[0033] In an advantageous embodiment, the slot groups have the same radial distance to the axis of rotation of the rotor shaft. This is advantageous because it enables smooth rotation.

[0034] The invention will now be explained in more detail with reference to schematic illustrations: In the Figure 1 The rotor of an electric motor according to the invention is shown in an oblique view. Figure 2 is a short circuit box fig 2 of the rotor shown in oblique view. In the Figure 3 A lamination stack 3 of the rotor is shown in an oblique view. Figure 4 The sheet metal package 3 is shown in a top view.

[0035] As shown in the figures, the rotor of the electric motor has a rotor shaft 1 which is inserted into a laminated core 3, which is connected as a composite part to a short-circuit box fig 2 is executed in this manner. The short-circuit rings of the short-circuit box are arranged axially on both sides. figs 2 produced by overmolding, especially with aluminum and / or copper.

[0036] The short-circuit bars connecting the short-circuit rings of the short-circuit cage are also produced during injection molding and fill axially directed grooves 41 of the lamination stack 3.

[0037] The sheet metal package 3 consists of individual sheets stacked in an axial direction.

[0038] Each of the individual sheets is preferably designed as a stamped part.

[0039] As in Figure 4As shown, each individual sheet of the laminated core has grooves 41 on its outer circumference, all of which are arranged at the same radial distance to the axis of rotation of the rotor shaft 1 and are regularly spaced apart from each other in the circumferential direction.

[0040] Radially within the slots 41, four groups of slots regularly spaced apart in the circumferential direction are provided to form four reluctance poles, so that the electric motor operated with the squirrel cage according to the principle of the asynchronous motor additionally has reluctance poles and therefore a grid-synchronous operation, in particular without slippage, is made possible.

[0041] Each slot group has three slots that are curved in a circular segment shape, with the corresponding circles of the respective slot group being concentrically aligned with each other.

[0042] In the circumferential direction along the circle assigned to the respective slot, each slot has a constant radial extent, the radial extent being referenced to the center of the circle assigned to it.

[0043] However, the radial extent of each slot increases with increasing distance from the center. Thus, a smoothing and / or equalization of the reluctance pole strength in the circumferential direction can be achieved at each reluctance pole.

[0044] The amount of the radial distance between two slots of the respective slot group that are closest to each other in the radial direction is always the same, in particular independent of the distance to the center point.

[0045] Each slot group has three concentrically arranged slots.

[0046] Each slot 40 is spaced at its respective end, arranged opposite to or in the circumferential direction, from one of the grooves 41 by a minimum distance, wherein the value of the minimum distance is identical for all ends of all slots.

[0047] The stator of the electric motor preferably has a three-phase winding. This allows a rotating magnetic field to be generated, enabling the electric motor to operate as a three-phase motor.

[0048] In further embodiments according to the invention, each slot group has more than three slots.

[0049] In further embodiments of the invention, the radial distance between two adjacent slots of the respective slot group increases with increasing distance from the center point. This allows for a further improved homogenization and / or equalization of the reluctance pole strength in the circumferential direction at the respective reluctance pole.

[0050] In further embodiments of the invention, instead of the aforementioned circular arc shape of the slots 40, an elliptical arc shape of the slots is provided, wherein the center point of the respective ellipse is used instead of the center point of the respective circle. While this improves the uniformity of the reluctance pole strength as a function of the circumferential angle around the focal point of the ellipses, it results in variable distances between the slots 40, rather than constant distances along their arc-shaped path.

[0051] In particular, a further improvement in the homogenization and / or equalization can be achieved if the foci of the corresponding ellipses are used instead of the centers of the circles. Reference symbol list

[0052] 1 Rotor shaft 2 Squirrel cage 3 Laminated core 40 Slot 41 Groove, in particular punched groove, for short-circuit bar

Claims

1. Electric motor comprising a rotor shaft (1), a squirrel cage (2) and a laminated core (3), the laminated core (3) being mounted on the rotor shaft (1), the laminated core (3) having, on its radially outer circumference in relation to the axis of rotation of the rotor shaft (1), grooves (41), which are uniformly spaced apart from one another in the circumferential direction, for receiving shorting bars of the squirrel cage (2), the laminated core (3) having slot groups, which are regularly spaced apart from one another in the circumferential direction in relation to the axis of rotation of the rotor shaft (1), for forming reluctance poles, each slot group having at least three slots (40), each slot (40) being configured in the shape of either a circle arc or an ellipse arc, the slots (40) of a particular slot group being oriented concentrically with one another, each slot (40), at its end arranged counter to the circumferential direction or in the circumferential direction, being spaced apart from one of the grooves (41) by a minimum distance, the value of the minimum distance being the same value, i.e. in particular being identical, for all the ends of all the slots (40), characterised in that the radial distance between each two closest neighbouring slots (40) of one slot group in relation to the centre point, in particular the circle centre point, the ellipse centre point or the ellipse focal point, increases as the distance from the centre point, in particular from the circle centre point, the ellipse centre point or the ellipse focal point, increases, the radial extent of each slot (40) in relation to the centre point, in particular the circle centre point, the ellipse centre point or the ellipse focal point, being - constant in the circumferential direction around the centre point, in particular the circle centre point, the ellipse centre point or the ellipse focal point, and being - independent of the circumferential angle around the centre point, in particular the circle centre point, the ellipse centre point or the ellipse focal point.

2. Electric motor according to claim 1, characterised in that the number of slot groups is four.

3. Electric motor according to any of the preceding claims, characterised in that in relation to the centre point, in particular the circle centre point, the ellipse centre point or the ellipse focal point, of the circle containing the relevant circle arc, each slot (40) is radially internally bordered by a first circle arc and radially externally bordered by a second circle arc.

4. Electric motor according to any of the preceding claims, characterised in that all the circles containing the circle arcs of all the slots (40) have an identical centre point, specifically an identical ellipse centre point or ellipse focal point, i.e. are arranged concentrically with one another.

5. Electric motor according to any of the preceding claims, characterised in that the radial extent of each slot (40) in relation to the centre point, in particular the circle centre point, the ellipse centre point or the ellipse focal point, increases as the radial distance from the centre point, in particular from the circle centre point, the ellipse centre point or the ellipse focal point, increases.

6. Electric motor according to any of the preceding claims, characterised in that the squirrel cage (2) is formed as a composite part together with the laminated core (3).

7. Electric motor according to any of the preceding claims, characterised in that the stator of the electric motor has a three-phase winding.

8. Electric motor according to any of the preceding claims, characterised in that the slot groups are formed identically to one another, i.e. in particular can be made congruent with one another as a result of rotation about the axis of rotation of the rotor shaft (1).

9. Electric motor according to any of the preceding claims, characterised in that the slot groups are at the same radial distance from the axis of rotation of the rotor shaft (1).