GB2339084A

GB2339084A - A liquid cooled three phase genrator

Info

Publication number: GB2339084A
Application number: GB9913836A
Authority: GB
Inventors: Gerhard Pflueger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1998-06-26
Filing date: 1999-06-14
Publication date: 2000-01-12
Anticipated expiration: 2019-06-14
Also published as: FR2780576A1; DE29811436U1; FR2780576B1; GB9913836D0; ITMI991275A1; GB2339084B; ITMI991275A0

Description

2339084 An electrical machine. in particular a liquid-coQled three-phase

generator The "invention takes as its starting-point an electrical machine, in 5 particular a liquid-cooled three-phase generator according to the type specified in the main claim.

The casing of such generators is surrounded, according to DE-PS 43 42 8 70, by a liquid jacket formed by a gap between the casing and another casing which is adjacent thereto and which in part also forms the liquid gap. Critical here, however, are - inter alia - high rotor temperatures, which have a disadvantageous effect on the overall generator concept. Affected 'in particular by such high temperatures are the electronic components, the bearing of the rotor of the generator and the performance characteristics of the generator. It is therefore essential to solve the problem of the dissipation of waste heat satisfactorily in respect of the rotor, in order to prevent excess temperatures near the components. With the aforementioned generator this is problematic, because the dissipation of waste heat is preferably effected via the rear end plate, but the rectifier and the regulator are arranged there, these components likewise generating waste heat.

The electrical machine with the characterising features of the main claim, on the other hand, has the advantage that the lowering of the rotor temperature and hence the avoidance of excess temperature near the components is improved, By this means a distinct increase in the power of the generator is also achieved, in particular by means of a thermal coupling of the rotor in the region of the rear face. At the same time a better distribution of the dissipation of heat is obtained. By means of the special design features specified in the subordinate claims the thermal resistance of the rotor 'in relation to the stator core, the stator frame and the coolant is lowered further.

2 Further advantages of the 'invention will be apparent from the following description and drawing of an embodiment example.

An example of an embodiment of the invention is reproduced in the drawing, which shows a longitudinal section through a claw pole generator.

The generator has a rouglily pot-shaped casing 10 which is sealed on its open side by a cover I I and at the bottom 10A of which a hub 12 is formed which receives a ball bearing 13. In this ball bearing one end 14A of a shaft 14 is supported, the opposite end 14B of which projects out of the casmig 10 and is supported in a stronger ball bearing 16 which is likewise supported in a hub 17 pertaining to the cover 11. The drive side of the generator is also situated here.

A stator 19 is arranged approximately in the middle of the casing 10 on the wall thereof 'in the region of ajoMit 39. Between the stator and the shaft a claw pole rotor system 20 taking the form of a conductive-component rotor is located, consisting of a magnet wheel 21 and a conductive component 22, the claws of which 1S interlock in alternating manner. Below the claws a fixed excitation winding 24 is located, arranged on a pole core 26 which is adjacent to the casing cover 11, is of roughly tubular shape and is secured to the cover 11 by means of screws which are not represented in any detail.

Between the cover I I and a hood 28 which is secured thereon there are located rectifier and regulator components for the generator, which, however, have not been dealt with in any detaiL since they are not essential to the invention and they are conventional with generators of this type.

As mentioned in the introduction, the dissipation of heat is essential for such generators. For this purpose a land-type, revolving cooling rib 30 is formed on the rear face of the generator at the bottom IOA of the casing 10, said cooling rib being situated between the hub 12 and a likewise annular bead 3 1. The bead 3 1 has a recess 34 on the inside, in which a ring land 29 rotates freely which is located on the face of the magnet wheel 2 1. A bulge 3 2 on the casing, which is located on the 3 face externally, serves to receive the rear winding head of a winding 33 of the stator 19. This bulge and also the outer surface of the casing 10 directly border a moderately wide liquid jacket 3 5, to which cooling liquid for cooling the generator is supplied via a channel 36, said cooling liquid being drained away to be cooled via a channel 37. The liquid jacket is bounded on the outside by a machine casing 38 or an outer casing. In this way a thermal coupling of the rotor to the coolant is obtained at the bottom I OA of the casing. By this means, not only is a better distribution of the dissipation of heat obtained, but an effective measure is provided for lowering the temperature of the rotor and increasing the power of the generator. Also affected by this, of course, are the electronic components, which are not represented in any detail, as well as the bearing of the rotor of the generator.

4

Claims

An electrical machine, in particular a liquid-cooled three-phase 5 generator with a stator (19) arranged in a pot-shaped casing (10) and with a claw-pole rotor system (20) secured to a driven shaft (14), and also with a thermal coupling of the casing (10) to a liquid jacket (35) at least partially surrounding said casing, characterised in that on the outside of the bottom (I OA), located opposite the drive side of the casmig (10), at least one cooling projection (30, 3 1) is formed which has 10 the liquid jacket (3 5) flowing around it.
2. Machine according to Claim 1, characterised in that the cooling projeefion (30) takes the form of a revolving ring land.
3. Machine according to Claim I and/or 2, characterised in that several revolving ring lands are formed at the bottom (10A) of the casing (10).
4. Machine according to one of Claims I to 3, characterised in that on the face of the claw-pole rotor system located opposite the drive side of the machine an 20 axially protruding ring land (29) is formed which rotates in a corresponding recess (3 4) at the bottom (I OA) of the casing.
5. Machine according to Claim 4, charactenised in that the recess (34) is surrounded by a bead (3 1) which is directed axiaUy outwards at the bottom (I OA) of 25 the casing.
6. An electrical machine substantially as herein described with reference to the accompanying drawing.