DYNAMOELECTRIC ROTARY MACHINE WITH AN AIR GAP ENCAPSULATION

Description

[0001] Dynamoelectric rotary through-ventilated machine according to the preamble of claim 1.

[0002] In dynamoelectric rotary machines with open-circuit ventilation and permanent magnets in their rotors, there is a risk that magnetic particles from the cooling air can accumulate in the air gap or on the surface of the rotor. Over a longer period of time, the air gap can become clogged with particles, causing damage or even blockage of the machine. Furthermore, even a few particles on the rotor increase the stray fields and thus lead to additional losses.

[0003] Sealing the air gap is already known from US 2006 / 0226717 A1 and EP 2 256 907 A1. Sealing the entire rotor is also known, as described in DE 10 2005 057 177 A1.

[0004] US 2012 / 212 086 A1 discloses an electric motor with a stator with windings and an internal rotor that uses a fan to move cooling air. This air also passes through the air gap.

[0005] From EP 1 271 747 A1 an electric motor is known which has an air-cooled stator and an encapsulated, uncooled rotor.

[0006] An air-cooled engine is also known from JP 2003 158 839 A.

[0007] From WO 2012 / 085 281 A2 an electrical machine is known in which the stator is liquid-cooled and is fluid-tightly sealed from the rotor by a can.

[0008] From JP S62 268 335 A, a rotating electrical machine is known, comprising a stator having a winding system arranged in substantially axially extending slots in an active part of the stator, which winding system forms a winding head on each of the axial end faces of this stator, wherein openings for outside air and cooling channels in the stator for the outside air are provided for through-ventilation of the stator, and comprising a rotor spaced from the stator by an air gap, wherein the rotor is positioned in a rotationally fixed manner on a shaft supported by bearings in a bearing shield, wherein the rotor has elements with an axial extension on its axial end faces, wherein openings for outside air and cooling channels in the rotor for the outside air are provided for through-ventilation of the rotor. This device forms the preamble of claim 1.

[0009] Based on this, the invention is based on the object of creating a dynamoelectric rotary machine with comparatively low expenditure, which can also ensure safe operation for a through-ventilation of such a machine to a sufficient extent by preventing deposits of magnetic particles in the air gap.

[0010] The solution to the stated problem is achieved by a dynamoelectric rotary continuous-ventilated machine having the features of claim 1. Embodiments of the invention, a traction vehicle and a wind turbine are the subject of subclaims.

[0011] By forming a carrier ring, which is arranged on the bearing plate or is part of the bearing plate, static and dynamic seals are formed with other elements of the dynamoelectric rotating machine. The bearing plate and the carrier ring can thus be formed as a single piece or composed of two, three, or more individual components.

[0012] These seals now specifically seal the air gap between the stator and rotor to prevent the ingress of particles that can adhere to the rotor's permanent magnets. These particles can become trapped in the air gap of dynamoelectric machines and thus contribute to increased stray losses. In the worst case, these particles can even clog the air gap, thus hindering or even preventing the rotor from rotating.

[0013] According to the invention, a completely encapsulated machine is no longer necessary, since the air-conducting channels in the rotor and stator can still be supplied with outside air without clogging the air gap.

[0014] This is particularly advantageous when such machines are used in traction drives, i.e. in rail transport, in mining trucks or in electric drives of vehicles in road traffic, which are to be cooled with outside air, which may contain harmful particles.

[0015] The invention now enables the construction of comparatively large and powerful, compact permanent magnet machines that feature comparatively simple air cooling, whether self-ventilated or forced-ventilated. Complex water jacket cooling systems are thus avoided.

[0016] The static seals can be implemented as felt mats on the winding head or as sealing lips made of insulating material. These exemplary sealing elements of the winding head are only arranged at specific sections on the radial inside of the winding head to avoid impairing the cooling effect. They exert their static sealing effect in conjunction with the corresponding counter-elements on the bearing shield's support ring.

[0017] Furthermore, the support ring of the bearing shield together with axial extensions of the elements arranged on the front side of the rotor form a dynamic seal, in particular a labyrinth seal, in order to also keep particles away from the air gap of the dynamoelectric machine.

[0018] Especially in the case of very compact, for example, relatively short axially active part lengths of a stator, such as disk-shaped machines with a radial flux arrangement, the invention ensures sufficient cooling, especially of the winding head area. The outside air can continue to cool the winding heads without the need for complex solutions for cooling or sealing the air gap from particles. The conductor length of a coil in the winding system, in particular a copper coil length in a slot, is equal to or less than the conductor length of this coil in the winding head.

[0019] According to the invention, sufficient cooling of the winding head by outside air is ensured and possible, especially in these machines, whereas in a completely enclosed, sealed machine, this cooling can only be achieved inadequately or with great effort. The outside air can also cool the stator and / or rotor. The heat generated along the active length of the stator is partially dissipated via the housing, even in axially short machines.

[0020] The invention and further advantageous embodiments of the invention are explained in more detail using an exemplary embodiment; in which: FIG 1 a partial longitudinal section of a dynamoelectric rotary machine, FIG 2 basic representation of length ratios of the winding system.

[0021] FIG 1 shows, in a partial longitudinal section, a dynamoelectric rotary machine 1 which is open-circuit ventilated, i.e., provides outside air as cooling air 17, 18 for a rotor 8 and / or a stator 2. This cooling air is provided by fans (not shown in detail), which can be designed as self-contained fans or external fans.

[0022] Within a housing 25, a stator 2 is arranged, which has axially extending stator cooling channels 3. In this case, the stator 2 is made of laminated material, but can also have other magnetic field-conducting elements, e.g., be designed as a single-piece sintered part.

[0023] A winding system 21 runs in essentially axially extending slots 22 of the stator 2 (not shown in detail), which forms winding heads 5 on the end faces 4 of the stator 2.

[0024] On the radial inner side of the winding head 5, a sealing surface 7 is provided, which is closed in the circumferential direction, at least over a predetermined axial area. This sealing surface can be glued, for example.

[0025] Spaced radially further inward by an air gap 6 is a rotor 8, which has permanent magnets 9. The rotor 8 can thus be part of a reluctance rotor with permanent magnets 9 or a purely permanently excited rotor 8. The permanent magnets 9 can be arranged on the surface of the rotor 8, as shown. These permanent magnets 9 can also be "buried" in the laminated core of the rotor 8.

[0026] The rotor 8 also has axially extending rotor cooling channels 10 through which outside air can flow.

[0027] The rotor 8 is rotationally fixedly connected to a shaft 19, which is mounted for rotation about an axis 24. The shaft 19 is thus held via bearings 23 in a bearing plate 11, each of which has a support ring 12. Means are provided on the support ring 12 of the bearing plate 11 that create a dynamic seal 15 and a static seal 16 in cooperation with corresponding elements of the rotor 8 and the winding head 5, respectively.

[0028] The bearing plate 11 and the carrier ring 12 can be constructed as a single piece or composed of two, three, or more individual components. Likewise, the carrier ring 12, with its counter-elements forming the dynamic seal, can be constructed as a single piece or in multiple parts.

[0029] The static seal 16 is formed by a counter element arranged on the carrier ring 12 and pressed against the sealing surface 7 of the winding head 5. Due to the live parts in the winding head 5, the counter element, for example a sealing lip, is made of insulating material. To improve the sealing effect, two or more such sealing lips can be arranged axially one behind the other and circumferentially. These sealing lips each press against the sealing surface 7, which of course must then also have a corresponding axial extension on the winding head 5.

[0030] The dynamic seal, which can be designed as a labyrinth seal, is formed by a corresponding axial extension of an element 13 on the front side 14 of the rotor 8 and correspondingly designed elements on the carrier ring 12 of the bearing plate 11.

[0031] Depending on the size and type of machine 1, such machine parts, such as carrier ring 12 and / or bearing plate 11, can be more easily constructed from one or more components.

[0032] Openings 26 in the bearing plate 11 and / or housing 25 serve for the inlet and outlet of the cooling air 17, 18 into and out of the machine 1.

[0033] By sealing the air gap 6 of the dynamoelectric machine 1, it is now ensured that no particles, in particular no magnetic particles, enter the air gap 6 when the dynamoelectric machine 1 is at a standstill, but also when it is in operation.

[0034] FIG 2shows in a basic representation the geometric length ratios of the winding system 21. This active part length 20 of a stator 2 is comparatively short, thus representing a disk-shaped machine in a radial flux arrangement. The conductor length of a coil 28 of the winding system 21, in particular a copper coil length in the slot 22, i.e. from point A to B, is equal to or less than the conductor length BC of the coil 28 in the winding overhang 5.

[0035] According to the invention, sufficient cooling of the winding head 5 is ensured, especially in these machines, which can only be cooled inadequately or with great effort in a closed machine. The heat generated along the active part length 20 of the stator 2 is also dissipated via the housing 25 in axially short machines.

[0036] This means that compact, even comparatively axially short, powerful, through-ventilated dynamoelectric machines 1 can now be used, in particular in traction vehicles such as rail vehicles, mining trucks or vehicles in road traffic.

[0037] The inventive air gap encapsulation is also used in generators of wind turbines, especially when cooling is to be carried out by outside air, possibly dehumidified.

Claims

1. Dynamo-electric rotary through-ventilated machine (1) comprising - a stator (2) which has a winding system (21), arranged in substantially axially extending grooves (22), in an active-part length (20) of the stator (2), said winding system forming a winding head (5) at each of the axial end faces (4) of said stator (2), wherein, for through-ventilation of the stator (2), provision is made of openings (26) for outside air and cooling channels (3) in the stator (2) for the outside air (18), - a rotor (8) which is spaced apart from the stator (2) by an air gap (6), wherein the rotor (8) is positioned rotationally conjointly on a shaft (19) which is supported via bearings (23) in a bearing shield (11), wherein, at its axial end faces (14), the rotor (8) has elements (13) with an axial extension, wherein, for through-ventilation of the rotor (8), provision is made of openings (26) for outside air and cooling channels (10) in the rotor (8) for the outside air (17), characterized in that the winding head (5) has a sealing element at its radial inner side, in that the rotor (8) has permanent magnets (9), and in that the bearing shield (11) has a carrier ring (12) which has means for forming a static and a dynamic seal (16, 15), in that provision is made of a static seal (16) by way of interaction with the sealing element (7) on the winding head (5) and of a dynamic seal (15) by way of interaction with the elements (13) with the axial extensions on the rotor (8), in order to seal off the air gap.

2. Dynamo-electric rotary machine (1) according to Claim 1, characterized in that the sealing element is in the form of a sealing surface (7) on the winding head (5).

3. Dynamo-electric rotary machine (1) according to Claim 2, characterized in that the sealing surface (7) on the winding head (5) is in the form of a felt mat able to be arranged there.

4. Dynamo-electric rotary machine (1) according to Claim 1, characterized in that the static seal (7) has at least one sealing lip composed of insulation material.

5. Dynamo-electric rotary machine (1) according to one of the preceding claims, characterized in that the carrier ring (12) on the bearing shield (11) has at least one radial extension (27) when seen in the circumferential direction, said at least one radial extension forming together with the sealing element, in particular the sealing surface (7) on the winding head (5), a static seal (16).

6. Dynamo-electric rotary machine (1) according to one of the preceding claims, characterized in that the carrier ring (12) on the bearing shield has counterpart elements which form together with elements (13) on the rotor (8) a labyrinth seal as a dynamic seal (15).

7. Dynamo-electric rotary machine (1) according to one of the preceding claims, characterized in that the conductor length (AB) of a coil (28) of the winding system (21) in the active-part length (20) of the stator (2) is less than or equal to the conductor length (BC) of said coil (28) in the winding head (5).

8. Traction vehicle, in particular rail vehicle, electric bus or mining truck, comprising at least one dynamo-electric rotary machine (1) according to one of the preceding claims.

9. Wind turbine having at least one dynamo-electric rotary machine (1) according to one of preceding Claims 1 to 7.