DE7242113U - ELECTRIC MOTOR WITH COOLING DEVICE - Google Patents

Description

Patent anw.-il. t: o
Dipl.-Ing.W. Royor
Dipl.-Wirtnch.-Ing. B.Jochom

Frankfurt om Mnin FroihPTr-vom-ol.oi η-Γ> ΐ, ι ·. 1R

In matters:

SKP Industrial Trading and
Development Company BV
Amsterdam, Netherlands
Overtoom 141-14-5

Electric motor with cooling device,

The invention relates to an electric motor with a stator, a rotor and radially inside the end-face end windings attached to the stator, shell-shaped, the bearings of the rotor shaft receiving bearing housings, which concentric Rows of access holes for between the spaces in front of the end faces of the rotor and the spaces in front of the end faces of the stator and circulating around the winding heads Have cooling air.

In modern industry, the demands on the production machine are constantly increasing, and one expects an ever more perfect way of working. This leads to a continuous increase in the number of electric motors, which should run faster and with less vibrations with ever better efficiency, but at the same time should be smaller and lighter than before. It is also often desirable that the temperatures developed during operation be lowered.

The desired properties of modern electric motors are technically not easy to implement, and more

8428 / November 15, 1972

Difficulties have recently grown out of environmental awareness. This is often not compatible with the increased requirements for technical performance, e.g. not then if at the same time the noise level in the workshop or in the Office should be lowered.

The increased temperatures and the high speed of modern electric motors make improved forced cooling, for example by means of more effective cooling air fans, necessary. Again but this increases the noise level to such an extent that a sound-insulating encapsulating the entire engine unit is ■ ,, has proven with the associated duct system to be necessary in order to reduce the noise to an acceptable level. Effective encapsulations, however, require so much space that they represent an obstacle to the widespread use of electric motors in mechanical engineering. Differences in pressure in the air ducts, airborne dust, moisture and dirt are other factors that hinder attempts to reduce noise. Special cooling air fans can also cause aerodynamic and resonance vibrations, which not only worsen human working conditions but also the properties of machines equipped with such electric motors.

The manufacturers of electric motors are aiming for smaller dimensions but any progress made in this direction is of little practical value because of the higher operating temperatures more compact engines. High speeds and wnrmobofitnndigo Materials Bind in (! .Losem 7Aisnmmonhnnr; no Panacea because the pressure inside the Mocor becomes so high during operation due to the rise in temperature, that the required shaft seals cannot function properly. As a result, there is an exchange of air between the interior of the engine and the surrounding atmosphere, which is often overloaded with contaminants. This brings ■

SKF 8428 / 15.11.19727242113 11.7.74

the risk of collapse or serious imbalances nit itself.

To the problems that exist with air-cooled electric motors To solve or turn off, attempts have been made to equip certain types of engines with a liquid cooling system, such as a Cooling water jacket, to be provided. This type of removal the heat loss is much more efficient than the traditional air-cooled arrangements. A major disadvantage the known cooling devices with water cooling so far consisted in the fact that during operation relatively strong temperature differences between the various Adjusted parts of the engine. That in director

Metallic contact with the cooling water jacket causes the stator hole pnket to be very violent and cools the inner areas of the stator and the end coils of the stator windings. These temperature differences have a detrimental effect on the performance and life of the engine. A more uniform engine temperature could increase performance and at the same time improve other important properties and service life. If, in addition, the temperature of the air trapped in the motor could be reduced to such an extent that it is only a few degrees above the ambient temperature, the increase in pressure in the motor as a result of the increase in temperature could be kept so low that the shaft seals and other pressure-sensitive components would function properly and would be prevented, ά & Λ Contaminants get into the interior of the motor.

The invention is therefore based on the object », o To create engine of the type mentioned, boi which air cooling and air cooling thornrt ninnvoli combined nind, dnß nio gogonnnitdf; ihro wone> nl: l i rhon NnHiteile repealed.

SKF 84-28 / 11/15/1972

The above object is achieved in an electric motor with air cooling of the type taken in be that the stator is surrounded by a heat-conducting connected to it, axially extending over the winding heads smantel, the inner wall together with motor end walls, which with him and are connected to the bearing housing, the spaces are bounded at the front in front of the stator, which flow paths for certain holes conveyed through the rotor and in the. Lagergchäujen nn don Wi cklunf-.r.köpi'on and then on the inner wall of the coolant casing. Form cooling air that is passed along, which can be returned to the spaces in front of the end faces of the rotor via other holes in the bearing housings in the ^{circuit n n rh its cooling on the cooling liquid jacket.}

According to the new proposal, a ι 'MM - ■■! · El. · W-1 rn - motor will meet all technical requirements in the! Lint! ι ■ -! ■ m ¹ low tendency to vibrate, low bet π oh ·· ,? fm ρ »· ■■ <' n , small dimensions with high performance r.owif nurh fin- · ι- I> ·. ■■ η f r. <> · Fulfill internal temperature distribution. Ix-m- ["! ·» R. ■. Ι.,: ■■■■, '· ' · ·; quiet, as the usual strong Gchl ^ i "π ι rhi --Im ■■ · .. - m weröen, and the r.:it Fl ii η ^ si pko t cf fu M '■ ■ ■ ,. ι. n ·. · · ■: ι> ⁽ n ·, ■ · ν ι effective during the ^ ¹ ! nchii r-ni -ί ·· <■■■ -ι ··. · ','; .. '. ii.n-- · disturbance d ^ r Arboi fcnboil i nr "rr ^r '... ri in I * · · · ι ■ ■ ■ ι,"i> ι ·'. ■ '■>: Kühlluftknnnl.p , Tnnl irwknmnir-ivi urr! -'Ι l ■ <<■., Ι o mnnrhir ^ l nnrii .in. ·· \\ <- \\ . Ii ni, > . I ■. ■■■ "i Zup muinni :. '' n μγιΊ ί ι ·. · mh-i '·' ■ ■ w. · ·., < m ι ιίΐι.

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Fig. 2 is a single-sided axial section

a motor end of a further embodiment,

Pig. 3 a modification of a detail of the embodiment according to Fig. 2 in a view corresponding to this.

In the different drawing figures are for identical Parts the same reference numerals have been used.

Fig. 1 shows an electric motor with a Stntorbler.hpaket; 1 with a winding 22, whose end winding head o with 2 are designated. A rotor 3 seated on a rotor shaft 4 is aligned coaxially to the door by means of bearings 24 and guided, which in cup-shaped bearing housings 5 and 6 are included, the z.rt. by welding and via ring-shaped Approaches 7 and 8 are attached to the end faces of the stator. The bearing housings lie on a coaxially to the stator axis aligned shoulder surface. The cupped Bearing housings 5 and 6 are radially inward of the end turns 2 arranged the stator winding.

The laminated stator core 1 is surrounded by a cooling liquid jacket, the inner wall 9 of which rests tightly on the laminated stator core and extends axially as far as over the end windings 2. Outside the inner wall 9 there is a channel reducer with channels 10 and 11 at the ends extending in the Urafangsrichtung of the coolant jacket. The circumferential channels are through a plurality of mutually spaced axial channels 12 connected. Outwardly there is> Knnolsyrtem through a jacket forming the outer wall of the cooling fluid Envelope completed. The cooling liquid is supplied via an inlet line 14 and fed via an inlet pipe 15 nb ^ oleiten. The supplied cooling liquid is denoted by 16. Dd. Ι direction of flow of the liquid along the channels of the

SKF 8428 / 11/15/1997? / 2 A 2 Ii 3] 1. 7. 7Λ

The jacket is indicated by arrows 17. During the operation of the photo, the heat losses are diverted from the stator core via the inner wall 9 to the cooling liquid. If no further measures had been taken, the heat generated in the winding heads 2 would be overlooked in the stator lamination stack, from there to the coolant ? hnhnr word on nln d: i ο dop. Laminated stator core. If a strong air flow directed towards the end is not directed against the winding heads, the heat radiation from the winding heads 2 to the surface 18 of the cooling jacket exposed to it causes only a very slight reduction in the temperature of the winding heads. However, by directing an outwardly directed, vigorously circulating air flow around all winding heads, very effective forced cooling of the same is achieved. This circulation of air is achieved in that the Lapsrgehäusen 5 and 6 a system of radially inner, with mutual spacing in a row and a number of radially outer passageways is provided. When the rotor 3 rotates, a continuous air flow 21 is conveyed to the outside through the holes 20, which is forced to zv through and over the windings 22 with their winding heads 2. stream. The air absorbs heat from the windings and thereby cools them. The air flow then sweeps further outward and comes into contact with the cooled inner surface 18 of the cooling liquid jacket, where the heat absorbed by the air from the windings is given off very quickly. The cooling surface 18 can be designed as an area enlarged by special measures. After the cooling air has given off the absorbed heat to the cooling liquid jacket, it is passed along a motor end wall 23, which is tightly connected to the cooling liquid jacket, to the radially inner row of through holes 19. Behind it, the air cools the bearing hub of the bearing housing and the bearing 24. As a result of the rotation

SKF 8428 / 15.11.19727242113 11.7.74

of the rotor, the cooling air is then passed through again to the outside the holes 20 promoted in order to cool the exposed stator windings again. On the way through the hunter case it cools the end face 25 of the rotor and its short-circuit rings 26. Because of the effective cooling of the the winding heads 2 accommodating spaces 27 'can be the temperature the circulating cooling air can be kept so low that the pressure increase caused by it is also very low remains small. A seal 28 at the lead-out end of the rotor shaft 4 is therefore expected to be free of interference is working.

The shell 13 and the motor end walls 2 can be of any suitable Material. V.'enn the heat radiation; optimal should be, metal would be preferable. On the other hand, has the noise attenuation Priority, these housing parts should be made of plastic or rubber.

Another embodiment of the invention is shown in Fig. and FIG. 3 shows an electric motor which, in addition to a cooling liquid jacket around the stator, is also liquid-cooled Has end walls.

The motor end wall 23 is made of pressed sheet metal and is hollow to allow a cooling liquid, e.g. To absorb water. The cooling water is through the inlet pipe 14- fed to the cavity 29 via a channel 30. Next to the rotor bearing 24 is the inner wall of the double motor end wall bent inwards to enlarge the water reservoir and the cooling surface between the water and the bearing. In addition, the air flow in the engine is appropriately deflected in this way.

Thn cooling niior .shromb now in ¹ final nr. By oinon: \ ^r p delayed Aunlnß, which is preferably dirnnotrnl f; op; one before the inlet 10, to areas with standing water

SKP 8 * 28 / 15.11.1972? 242113 11. "7.

vormirten. The aura can be found in the stntorbloohpnkol; iimpirbondon Kiihlwnnnnrmnntnl ornirr'ockon.

It is possible to supply cooling water to both hollow end walls Construction according to Fig. 3 can be selected. There are two separate pipes or lines 31 within the inlet ducts; 14- attached, each of which has a flow of water to the associated End wall leads. The lines 31 can be made of rubber, for example exist. Alternatively, they can also be cast. This can be useful, for example, if the shell or outer wall 13 has a casting.

Since the motor end walls are not exposed to great stress, because the bearings are supported on the stator core Bearing housings are included, the end walls can be attached and sealed in a simple and elegant manner will. Fig. 2 shows z.3. an end wall 23 made of pressed sheet metal and a sheath 13 made of rubber. In the example, the end wall is connected to both the bearing housing by means of O-rings 32 5 and also connected to the coolant jacket 9. A clamping ring 33 holds the rubber sleeve 13 in tight contact with an axial flange 34 of the end wall. It takes in this Fßll no screw connections or similar more expensive and complicated structural parts.

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SKF 8: 8 / 11/15/1972

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Claims (6)

Do LuHbWB. sayings 1. Electric motor with a stator, a rotor and radial attached to the stator within the end windings, cup-shaped, the bearings of the! rotor shaft receiving Bearing housings, which concentric rows of through holes for between the spaces vjr the end faces of the rotor and have cooling air circulating in the spaces in front of the end faces of the stator and around the winding heads, characterized in that the stator (1) by a coolant jacket which is connected to it in a thermally conductive manner and extends axially beyond the winding heads (2) (9, 13) is surrounded, the inner wall (9) of which together with the motor end walls (23) which house with it and the bearing (5, 6) are connected, the spaces (27) at the front in front of the stator (1) bounded which flow paths for through the. Rotor (3) funded, through certain holes (20) in the bearing housings (5, 6), on the winding heads (2) and then on the inner wall (9, 18) of the cooling liquid jacket (9, 13) along cooling air (21), which in the circuit after their cooling on the cooling liquid jacket over other Holes (19) in the bearing housings * (5 »6) back into the housing can be returned in front of the end faces of the rotor (3). 2. Electric motor according to claim 1, characterized that at least one of the engine end walls (23) hollow and connected to the liquid cooling system (1A-) is. 3 * electric motor according to claim 2 with two hollow motor end walls, characterized by dnß inside the inlet line (14) of the cooling liquid jacket (9i 13) separate lines or pipes (31) are arranged, 8428 / 11.15.1972 7242113 11 7 7 / _f which coolant to the hollow engine> ndwnndon (P3) to lead. 4-, electric motor according to claim 2, characterized in that Rek that the outlet conduit of the hollow engine end walls (23) is diametrically opposite its inlet conduit (30; 31) is arranged. 5. Electric motor according to claim 2, characterized that at least one hollow motor end wall (23) is made from sheet metal pressings. 6. Electric motor according to claim 2, characterized in e e that at the junctions between the motor end wall (23) and the coolant jacket (9) and the bearing housing (5, 6) O-rings (32) made of elastic material are arranged, which have an immediate Allow contact between the coolant and the bearing housing (5 »6). SKF 8428 / 11/15/1972