Electric motor

Abstract

Electric motor comprising a stator, the stator winding (3) of which is surrounded by a stator lamination stack (1), wherein a stator inner sleeve (4) is provided which limits the space for the stator winding (3) inwards, i.e. towards the rotor of the motor, wherein the stator winding (3) is provided to be potted between the stator lamination stack (1) and the stator inner sleeve (4) by means of potting compound (40), wherein the stator winding (3) is arranged radially inside the stator lamination stack (1) and radially outside the stator inner sleeve (4), wherein the stator lamination stack (1) has slots (41) on its inner side, characterized by the fact that the slots (41) are filled only with the potting compound (40), so that the stator winding (3) is held in a form-fitting manner on the stator lamination stack (1) in the circumferential direction by means of the potting compound (40).

Description

[0001] The invention relates to an electric motor.

[0002] It is known that electric motors have a rotor and a stator. In the case of an asynchronous motor, the rotor includes a squirrel-cage rotor, while in the case of a synchronous motor, it contains permanent magnets. The stator has a winding mounted on a stator core.

[0003] From DE 696 01 623 T2 it is known to arrange the stator winding in recesses of the stator lamination stack.

[0004] A canned tube motor is known from DE 10 2006 049 292 A1.

[0005] An electric rotating machine is known from US 2008 / 0 005 888 A1.

[0006] From DE 696 26 192 T2 a molding compound and a molded motor are known.

[0007] From DE 22 23 906 A a stator of an electrical machine such as a motor or generator is known.

[0008] From DE 33 08 006 A1, a rotating electric machine with an air gap winding is known as the closest prior art.

[0009] From DE 14 88 502 A a mechanical unit consisting of two coaxial parts rotating relative to each other and a method for connecting the components of one of these parts is known.

[0010] The invention is therefore based on the objective of further developing an electric motor, whereby the motor should have high performance in a small installation volume.

[0011] According to the invention, the problem is solved in the electric motor according to the features specified in claim 1.

[0012] Important features of the invention in the electric motor are that it comprises a stator whose stator winding is surrounded by a stator lamination stack, wherein an inner stator sleeve is provided which limits the space for the stator winding inwards, i.e. towards the rotor of the motor, where the stator winding is potted with potting compound between the stator lamination stack and the stator inner sleeve, wherein the stator lamination stack has grooves, in particular on its inside, which are filled by the potting compound, so that the stator winding is positively locked in the circumferential direction by means of the potting compound.

[0013] In particular, the stator winding is arranged radially within the stator lamination stack, which has several slots arranged around the circumference, in particular axial slots, especially between 4 and 12 slots, and the stator winding is embedded in potting compound which fills the slots and is bounded radially outwards by the stator lamination stack and radially inwards by the stator inner sleeve.

[0014] An advantage of this design is that the stator winding is designed as an air gap winding, i.e., it is not inserted into slots of the stator lamination stack, but is radially positioned within the stator lamination stack and is therefore easy to manufacture, and the stator is held in place circumferentially by means of the potting compound.

[0015] In an advantageous embodiment, the potting compound contains a proportion of particles. This is advantageous because it achieves high stability, as the potting compound mechanically stabilizes the stator winding and the stator inner sleeve. Furthermore, it improves heat dissipation from the stator winding to the stator lamination stack and from there, via the motor housing, to the surrounding environment. This is because the potting compound can be formulated accordingly. In addition, the deflection areas of the stator winding—that is, the sections protruding axially from the stator lamination stack—are also supported and thus mechanically stabilized by the potting compound, particularly in the event of vibrations or similar disturbances. The potting compound also facilitates heat dissipation from the deflection area. Finally, it contributes to increasing the electrical insulation distance between the stator winding leads.

[0016] The stator inner sleeve serves two purposes: firstly, it acts as a boundary when potting the stator with potting compound, and secondly, it stabilizes the areas protruding axially from the stator lamination stack. Furthermore, it limits and stabilizes the adjacent area of ​​potting compound, thus contributing to improved heat dissipation from the deflection area of ​​the stator winding.

[0017] In an advantageous embodiment, the particle content is between zero and fifty percent by volume, particularly between 20 and 40 percent by volume, and especially 30 percent by volume. It is advantageous that the overall elasticity and compressibility of the potting compound, including the particles, is sufficiently improved to reduce the forces acting on the stator inner sleeve to such an extent that damage is prevented.

[0018] In an advantageous embodiment, the compressibility of the particles is greater than that of the remaining potting compound, in particular at least five times greater, and in particular at least ten times greater. It is advantageous that the stator inner sleeve is sufficiently protected against overload.

[0019] In a preferred embodiment, the stator inner sleeve is made of a fiber-reinforced composite material. The advantage here is that particularly high strength can be achieved at a low weight. Furthermore, it allows for a very good bond between the potting compound and the composite material, as the composite itself is encased in a resin, thus ensuring excellent adhesion.

[0020] In an advantageous embodiment, the potting compound contains an epoxy resin and / or a polyester resin. A benefit here is that thermally conductive material exhibiting high electrical insulation strength against leakage currents and high dielectric strength can be used.

[0021] In an advantageous embodiment, the particles are essentially hollow bodies, particularly with an average diameter between 1 µm and 1 mm, and especially between 10 µm and 300 µm. The advantage here is that a particularly high quantity of particles can be added and particle collapse can be prevented. In contrast, a particle several millimeters in size can collapse and thus cause damage. Furthermore, the electrical insulation strength can be better ensured.

[0022] In an advantageous embodiment, the particles contain silicate or silicate glass, particularly in their wall. This offers the advantage of particularly simple manufacturing and good miscibility with the resin of the potting compound. This is achieved, in particular, through appropriately optimized surface tensions.

[0023] In an advantageous embodiment, the stator winding protrudes axially from the stator lamination stack. An advantage here is that the deflection area of ​​the stator winding can be cooled by means of the potting compound.

[0024] In an advantageous embodiment, the stator lamination stack is provided within a surrounding motor housing. An advantage of this design is the efficient heat transfer to the motor housing. In particular, the stator lamination stack can be shrink-fitted, thus achieving a low thermal resistance. For shrink-fit connection, a temperature difference of more than 50 Kelvin is created between the stator lamination stack and the motor housing when they are joined together.

[0025] In an advantageous embodiment, the inner stator sleeve, together with a portion of the potting compound, mechanically supports the protruding part of the stator winding and dissipates heat from this part to the stator lamination stack and / or motor housing. A key advantage is that the protruding sections of the winding can be cooled via the otherwise distant stator lamination stack. This is particularly important because especially high temperatures, also known as hot spots, can be reached in the bending areas.

[0026] In an advantageous embodiment, the thermal resistance from the protruding part through the potting compound to the stator lamination stack is greater than from the protruding part to the motor housing. The advantage here is that improved heat dissipation can be achieved.

[0027] In an advantageous embodiment, the stator winding is made of copper or a copper-containing material. The advantage here is that high thermal conductivity and low ohmic losses can be achieved.

[0028] In an advantageous embodiment, the potting compound has a high specific thermal conductivity, in particular at least ten times better than air. This is advantageous because heat dissipation can be improved, especially in the deflection area, which would otherwise be surrounded by air.

[0029] In an advantageous embodiment, the motor housing has cooling channels, in particular cooling channels through which a cooling medium, especially a liquid cooling medium, can flow. It is advantageous that the motor housing and the stator lamination stack located on its inner side can be effectively cooled.

[0030] Further advantages arise from the sub-claims.

[0031] The invention will now be explained in more detail with the help of illustrations: In the Fig. Figure 1 shows a sectional view of an electric motor according to the invention. In the Fig. Figure 2 shows an enlarged section, which is in Fig. is marked with 1.

[0032] The rotor of the motor is mounted in the motor housing 2 via bearings 8, which is closed on one side with a flange part 9, with a sealing ring 6 being provided between flange part 9 and motor housing 2.

[0033] A stator lamination stack 1, on which the stator winding 3 is arranged, is provided on the inside of the motor housing 2, wherein the inside of the stator is in turn limited to the inside of the motor, i.e. towards the rotor, by means of a stator inner sleeve 4.

[0034] Potting compound is cast between the stator inner sleeve 4 and the motor housing 2, thus mechanically stabilizing the stator winding 3 and ensuring good thermal conductivity between it and the motor housing 2. For this purpose, the potting compound has a correspondingly high thermal conductivity. Furthermore, cooling channels 5 are provided in the motor housing 2, through which a cooling medium, preferably oil or water, can flow.

[0035] The stator winding 3 protrudes axially from the stator lamination stack 1 at both axial ends. This protruding part of the stator winding is supported by the stator inner sleeve 4 and the adjacent, also protruding, potting compound area.

[0036] An angle sensor 7 is provided at the first axial end region of the rotor to detect the angular position of the rotor.

[0037] The stator inner sleeve 4 is preferably made of a fiber composite material.

[0038] The potting compound is made of epoxy resin and / or a polyester resin, with an admixture of preferably 30 volume percent of microparticles.

[0039] The microparticles consist of silicate, primarily in a spherical form.

[0040] Since the stator lamination stack is located on the outer side of the stator, particularly adjacent to the motor housing 2, temperature increases exert inward pressure on the stator inner sleeve 4, which could lead to its destruction. However, this is prevented by the additives, which reduce these pressure forces. This is because the microparticles are compressible, and significantly more compressible than the rest of the potting compound, which is either not compressible at all or only slightly compressible.

[0041] Preferably, the microparticles are made of silicate spheres. It is important that the microparticles are designed as spheres containing a cavity.

[0042] In other embodiments according to the invention, admixtures between 1 and 50 percent by volume are also advantageous.

[0043] In the Fig. Section 3 explains the structure of the stator in more detail, with in Fig. Figure 4 shows an enlarged section. Here, the stator winding is designed as an air gap winding, i.e., arranged radially inside the stator lamination stack 1 and radially outside the rotor, with a minimum distance to the rotor being maintained in the radial direction.

[0044] The potting compound 40 surrounds and penetrates the stator winding 3. Since the stator lamination stack also has axial slots 41 into which the potting compound penetrates, the stator winding is thus held in a form-fit manner in the circumferential direction by means of the hardened potting compound 40.

[0045] The stator inner sleeve thus limits the potting compound. The holding function in the circumferential direction is performed by the potting compound filling the grooves 41, despite the particles in the potting compound, which on the one hand increase compressibility, thereby increasing stability through the stator inner sleeve, and on the other hand reduce air and creepage distances, thus decreasing dielectric strength. Reference symbol list 1 Stator lamination package 2 Motor housings 3 Stator winding 4 Stator inner sleeve 5 cooling channels 6 sealing ring 7 Angle sensor 8 bearings 9 Flange part 40 potting compound 41 axial groove

Claims

Electric motor comprising a stator, the stator winding (3) of which is surrounded by a stator lamination stack (1), wherein a stator inner sleeve (4) is provided which limits the space for the stator winding (3) inwards, i.e. towards the rotor of the motor, wherein the stator winding (3) is provided between the stator lamination stack (1) and the stator inner sleeve (4) by means of potting compound (40), wherein the stator winding (3) is arranged radially inside the stator lamination stack (1) and radially outside the stator inner sleeve (4), wherein the stator lamination stack (1) has grooves (41) on its inner side, characterized in that the grooves (41) are filled only by the potting compound (40), so that the stator winding (3) is held in a form-fitting manner on the stator lamination stack (1) in the circumferential direction by means of the potting compound (40). Electric motor according to claim 1, characterized in that the stator winding (3) is arranged radially within the stator lamination stack (1), that it has several slots (41) arranged around the circumference, in particular axial slots (41), especially between 4 and 12 slots (41), and that the stator winding (3) is embedded in potting compound (40) which fills the slots (41) and is bounded radially outwards by the stator lamination stack (1) and radially inwards by the stator inner sleeve (4). Electric motor according to at least one of the preceding claims, characterized in that the potting compound (40) contains a proportion of particles. Electric motor according to at least one of the preceding claims, characterized in that the proportion of particles is between zero and fifty percent by volume, in particular between 20 and 40 percent by volume, in particular 30 percent by volume. Electric motor according to at least one of the preceding claims, characterized in that the compressibility of the particles is greater than the compressibility of the remaining potting compound (40), in particular at least five times greater, in particular at least ten times greater. Electric motor according to at least one of the preceding claims, characterized in that the stator inner sleeve (4) is made of a fiber composite material. Electric motor according to at least one of the preceding claims, characterized in that the potting compound (40) contains an epoxy resin and / or a polyester resin. Electric motor according to at least one of the preceding claims, characterized in that the particles are essentially designed as hollow bodies, in particular with an average diameter between 1 µm and 1 mm, in particular between 10µm and 300µm. Electric motor according to at least one of the preceding claims, characterized in that the particles contain silicate or silicate glass, in particular in their wall. Electric motor according to at least one of the preceding claims, characterized in that the stator winding (3) protrudes axially from the stator lamination stack (1). Electric motor according to at least one of the preceding claims, characterized in that the stator lamination stack (1) is provided in a motor housing (2) surrounding it. Electric motor according to at least one of the preceding claims, characterized in that the stator inner sleeve (4) together with a part of the potting compound (40) mechanically supports the protruding part of the stator winding (3) and dissipates heat from this part to the stator lamination stack (1) and / or motor housing (2). Electric motor according to at least one of the preceding claims, characterized in that the thermal resistance from the protruding part via the potting compound (40) to the stator lamination stack (1) is greater than from the protruding part to the motor housing (2). Electric motor according to at least one of the preceding claims, characterized in that the stator winding (3) is made of copper or a copper-containing material. Electric motor according to at least one of the preceding claims, characterized in that the potting compound (40) has a high specific thermal conductivity, in particular at least ten times better than air and / or wherein the motor housing (2) has cooling channels (5), in particular cooling channels (5) through which a cooling medium can flow, in particular cooling channels (5) through which a liquid cooling medium can flow.

Images