JP2859387B2 - Electric machine - Google Patents

Description

The present invention relates to an electric machine according to the preamble of claim 1, in particular to a three-phase alternator for motor vehicles.

2. Description of the Related Art According to Japanese Utility Model Laid-Open Publication No. Sho 57-65570, it is already known to provide a heat radiation fin for discharging heat to a stator casing of an electric motor. Is filled with a thermally conductive mold resin together with the annular gap. In that case, the coil head is completely embedded in the mold resin. Since the heat discharge characteristics of the mold resin are not so good, sufficient heat radiation from the coil head is impossible, and the output of the electric machine is limited based on the extremely high heating of the coil head.

Furthermore, according to Swiss Patent No. 317647, it is known to inject or bury the outer gap of the stator laminated iron core of the electric motor together with the coil head of the stator winding by means of an injection material made of resin or the like. . The material used for embedding the coil head used here provides good protection against external mechanical damage to the coil head, but poor heat transfer due to poor thermal conductivity There is a disadvantage that. Furthermore, the resins used here tend to take in air due to their relatively large shrinkage during curing.

Furthermore, according to DE-A-271 11053, in order to protect the stator against heat generated in the rotor of the electric machine and to better discharge the heat radiated from the rotor into the stator casing. To
It is known to dispose a heat conducting member between a stator winding and a rotor, and the comb-like projections of the heat conducting member are pushed into a stator groove, and the outer surface of the heat conducting member is used for discharging heat. Is brought into contact with the stator casing. According to this measure, the stator windings are protected against radiation of heat from the rotor, but since the coil head is embedded in an insulating material which serves for thermal as well as electrical insulation, the coil head The heat generated electrically is only discharged to the casing via the stator laminated iron core, and it is impossible to discharge the heat generated in the coil head itself satisfactorily.

[Problem of the Invention] Therefore, an object of the present invention is to provide an electric machine that can satisfactorily discharge heat loss in a coil head to the outside.

[Means for Solving the Problems] The gist of the present invention that solves the above problems is as described in claim 1.

[Operation and Effect of the Present Invention] In the electric machine according to the present invention configured as described in claim 1, heat loss generated in the coil head is transferred to the heat conduction ring, ie, the metal ring, by the relatively thin insulating layer, ie, plastic. Through the outer surface of the electromechanical casing. Further, an advantage of the present invention is that negligible shrinkage of the injectate can be neglected, thus avoiding air entrapment or air gaps between the insulating layer of the coil head and the metal ring. .

The features described in the other claims are advantageous features of the invention. It is particularly advantageous that a metal ring for accommodating the coil head is provided on only one side of the stator laminated iron core of the electric machine, and the metal casing of the stator comprises an inner step on the other side of the stator laminated iron core, which comprises a stator. It serves as a stop for the laminated iron core, which is placed over the coil head in close proximity and forms a radially inward annular protrusion which covers the end face of the coil head. is there.

In an electric machine with two stator windings arranged axially behind one another, for example a twin-induction generator, the generator casing has a T-shaped cross section between the two stator-laminated iron cores. It is advantageous to provide a collar facing the inner coil head, which covers the adjacent inner coil head for heat dissipation. The two outer coil heads are then covered by two angle-shaped metal rings which are pressed into the metal casing from the outside. If the stator casing is cup-shaped, use a T-shaped metal ring instead of a T-shaped collar for the two inner coil heads next to each other, which serves as a stopper for the adjacent laminated stator core. You can also.

[Embodiment] The three-phase AC generator indicated by reference numeral 10 in FIG. 1 is used for supplying current to heavy-duty automobiles or construction machines. This three-phase AC generator includes a stator 11, a claw-pole type rotor 12, and a stationary excitation winding 14, and the rotor 12
Is fixed to the drive shaft 13. The drive shaft 13 is mounted at its rear end via a ball bearing 15 in a bearing shield of a metal casing 17 of the generator. The drive shaft is also a ball bearing on the drive side
The drive flange 19 of the generator is supported via 18.
The drive flange 19 closes the cup-shaped metal casing 17 with respect to the drive side. The excitation winding 14 is insulated and attached to the magnetic flux guiding ring 20, the magnetic flux guiding ring is fixed to the drive flange 19 by a screw 21 at its end face, and the drive shaft 13 passes through the drive flange 19. I have. The rotor 12 includes two magnetic induction members 12a and 12b which are formed in a claw pole shape and are magnetically insulated from each other, and are tightly fitted to a drive shaft. These magnetic guide members are held together by two non-magnetic holding rings 22,23. The drive is preferably effected from the internal combustion engine via a belt and a belt wheel 24 provided at the drive end of the drive shaft 13. The stator 11 of the generator 10 is composed of an annular stator laminated iron core 25, and a groove is formed inside this,
A three-phase stator winding 26 is accommodated in this not-shown groove, and its coil heads 26a and 26b are
5 protrudes from the groove at both end faces. In order to discharge the heat loss generated in the generator from the outer peripheral surface of the metal casing 17, the generator 10 is inserted into the closed cooling casing and then fixed by the drive flange 19, thereby flowing through the cooling casing (not shown). Heat is dissipated by a cooling medium, for example, cooling water.

In order to effectively discharge the heat loss from the coil heads 26a and 26b, a metal ring 27 is pressed between the metal casing 17 and the left coil head 26a until the metal ring 27 reaches the stator laminated iron core 25. The metal ring 27 has an angle-shaped cross section and is close to the end face of the front coil head 26a. Metal ring 2
7 is a coil head 2 on its outer surface for effective heat dissipation
It is planarly connected to the metal casing 17 over the entire depth of 6a. The metal casing 17 of the stator 11 is provided with an inner step 28 for discharging heat from the right coil head 26b on the right side of the stator laminated iron core 25 on the side opposite to the metal ring 27. It serves as a stopper for the stator laminated iron core 25 and also covers the coil head 26b in close proximity. The metal casing 17 then has a radially inwardly directed annular projection 17a which covers the end face of the coil head 26b. The gaps left between the coil head 26a and the metal ring 27 and between the coil head 26b and the projection 17a are advantageously made of a thermally conductive plastic 29.
Has been filled by.

In the embodiment shown in FIG. 2, a twin induction rotor (Dopp
The lower half of the generator 30 with elleitstueck-Laeufer 31 is shown in cross section. Two claw-pole type guide members / rotors 33, 34 are fixed to the drive shaft 32 in a mirror-symmetrical manner. In this case, the claw poles cover one of the excitation windings 35, 36, respectively. Each excitation winding 35, 36 is insulated and mounted on a magnetic flux induction ring 37, 38. The flux guide rings are each screw-fixed in their cross section to casing flanges 39, 40 of generator 30. The stator 41 of the generator 30 is provided with two stator laminated iron cores 42, 43 arranged one behind the other in the axial direction, the stator laminated iron core being surrounded by a metal casing 44 provided with a cooling medium passage. And supports the stator windings 45 and 46.

The two coil heads 45a, 46a outside the stator windings 45, 46 are each covered by two angle-shaped metal rings 27 for heat dissipation, as in the embodiment of FIG. In this case, the adjacent inner coil heads 45b, 46b are covered by an inwardly directed T-shaped collar 47 of the metal casing 44. In this case too, the T-shaped collar 47 forms one stop for each of the laminated stator cores 42, 43.

FIG. 3 shows a cup-shaped metal closed only by a flange 52 on the drive side only, whereas both magnetic induction systems of the three-phase alternator 30 shown in FIG. 2 are held from both end faces. A twin induction three-phase alternator 50 with a casing 51 is shown. Instead of the collar 47 integrally formed on the casing in FIG. 2, in the embodiment of FIG. 3, two stator-laminated iron cores are arranged axially one behind the other.
An H-shaped metal ring 53 is press-fitted flat into the metal casing 51 for heat dissipation between the 42 and 43, and the metal ring grips the inner coil heads 45b and 46b. The outer coil heads 45a, 46a are in this case gripped by U-shaped metal rings 54, 55, which also cover the inner periphery of the coil heads with stator-laminated iron cores 45,4.
It covers up to the air gap before 6. A thermally conductive plastic is likewise preferably arranged through this air gap. This plastic has coil head and metal ring 53,5
Fill the gap between 4,55. In a preferred embodiment, the gap is filled with silicone rubber. A particularly good heat dissipation into the metal casing is obtained by the fact that the metal rings 53, 54, 55, which are pressed flat into the metal casing 52, are made of aluminum.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of a first embodiment of the present invention, FIG. 2 is a partial longitudinal sectional view of a second embodiment of the present invention, and FIG. 3 is a partial longitudinal sectional view of a third embodiment of the present invention. It is. 10 ... three-phase alternator, 11 ... stator, 13 ... drive shaft, 14 ... excitation winding, 15 ... ball bearing, 16 ... bearing shield, 17 ... metal casing, 18 ... ball bearing , 19 …… Drive flange, 20 …… Flux induction ring, 21 …… Screw, 22,23
... retaining ring, 24 ... belt wheel, 25 ... stator laminated iron core, 26 ... stator winding, 26a, 26b ... coil head, 27 ... metal ring, 29 ... plastic, 30 ...
... Three-phase alternator, 31 ... Twin induction rotor, 32 ...
Drive shaft, 33,34… Induction member / rotor, 35,36… Excitation winding, 37,38… Flux induction ring, 39,40 …… Casing flange, 41… Stator, 42,43 …… Stator Layered iron core, 44 …… Metal casing, 45,46 …… Stator winding, 4
5a, 45b, 46a, 46b …… Coil head, 47 …… Color, 50…
... three-phase alternator, 51 ... metal casing, 53, 54, 55 ...
… Metal ring

Claims (7)

(57) [Claims] 1. An electric machine, comprising: a surface-cooled stator, a claw-pole type rotor, and a stator laminated iron core, wherein the stator laminated iron core supports a stator winding; The head protrudes from the groove at both end surfaces of the stator laminated iron core, the stator laminated iron core is inserted into the metal casing, heat loss is transferred to the cooling medium via the outer peripheral surface, and the coil head is In a form in which the metal ring is electrically insulated and surrounded by a heat conductive metal ring, and the metal ring is heat conductively connected to the metal casing, at least the metal case (17, 44, 51) Between one coil head (26a, 45a, 46a), a metal ring (27, 55, 54) placed close to the end face of the coil head extends to the stator laminated iron core (25, 42, 43). Push Are, the metal ring coil head (26a, 45a, 46a) are in surface-bound to the metal casing (17,44,51) over the entire depth of,
An electric machine characterized in that the gaps left between the coil head and the metal ring are filled with plastic (29). 2. A metal casing (17) of a stator (11) having an inwardly facing inner step (28) at an end face of a stator laminated iron core (25), wherein the inner step is A radially inwardly extending annular projection (forming a stopper for the laminated iron core (25) and extending close to the coil head (26b) and covering the end face of the coil head (26b); Electric machine according to claim 1, forming 17a). 3. An electric machine (30) of the twin induction type in which a metal casing (44) faces inwardly between two stator laminated iron cores (42, 43) axially spaced from one another. A collar (47) having a T-shaped cross section covers the adjacent inner coil heads (45b, 46b) for heat discharge, and both outer coil heads (45a, 46a) are angled. Covered by two metal rings (27) of
The electric machine according to claim 1. 4. The electric machine according to claim 3, wherein the collar (47) having a T-shaped cross section forms one stop for both stator-laminated iron cores (42, 43). 5. In a twin induction type electric machine, an H-shaped metal ring (53) is provided between two stopper laminated iron cores (42, 43) which are axially spaced apart from each other. 3. The electric machine according to claim 1, wherein the metal ring is pressed flat into the metal casing for fixing the coil head to the adjacent inner coil head. 4. 6. The method as claimed in claim 1, wherein the gap left between the coil head and the metal ring or metal casing is filled with a thermally conductive, electrically insulating plastic (29) by injection. The electric machine according to any one of the preceding claims. 7. The metal ring (27,53,54,55) pressed flat in a metal casing (17,44,51) made of aluminum. An electrical machine as described.