US1375699A - Wedge or key for slotted dynamo-electric-machine elements - Google Patents

Description

M. I. ILG.

WEDGE 0R KEY FOR SLOTTED DYNAMO ELECTRIC MACHINE ELEMENTS.

APPLICATION FILED MAY 27. l9l5- RENEWED SEPT-15,1920.

Patented Apr. 26, 1921.

UNITED STATES PATENT oFFIcE.

MAX JOSEPH ILG, or NUREMBERG, BAvAnrA, GERIEANY, AssrenoR T SIEMENS-V scnucxnn'r WERKE e. M. B. H., or sIEMnNss'rAn'r, near-2. ans-LIN, GERMANY.

WEDGE OR KEY FOR SLOTTED DYN AIiTO-ELECTRIC-MACHIN E ELEMENTS.

Application filed May 27, 1915, Serial No. 30,844.

' To all whom it may concern:

and in order to be able to easily exchange parts of the winding which have become damaged, it is most convenient, to use socalled open slots, that is to say slots'of -'a cross-section which is not smaller at the top of the slot than at the bottom, because the winding elements may be readily inserted into and taken out of a slot of this kind.

Open slots on the other handhave the disadvantage that they do not give a sufiiciently large surface of the slotted iron body in order to have a magnetic path as large as possible for the entrance of the magnetic lines of force into said body, thereby necessitating a larger size of the iron body and a surplus of ampere turns for generating the field. Also "other inconveniences are sometimes found in addition to this when open slots are used in dynamoelectric machine elements. r

Attempts have been made to avoid these disadvantages connected with open slots by closingthe slots by means of magnetizable wedges or keysafter having the winding inserted into the slots. Many forms of such magnetizable keys or wedges and many modes for keeping the same safely'in position have been devised and employed in practice. Of all these constructions, however, none has so far been able to fully meet the teeth Z and Z there are provided. two

the practical requirements.

The object of my present inventionis to devise a key or wedge forthe slots of dynamo electric machine elements such as armatures, which more fully meets the practical requirements and which especially results in a number of mechanical and magnetic properties that are not found in the ordinary constructions; Y

My invention is an improvement of the ordinary slot-key generally of the shape of a 'flatlwedge, which consists in the first Specification of Letters Patent.

Patented Apr. 26, 1921. Renewed sept'ember 15, 1920/ Serial No. 410,483;

place of magnetizable parts serving asa proper path for the lines of force coming out of the teeth of the'slotted iron body or core, or in other wordsto increase the surface of said body for the'passageof lines of force; these parts may therefore be called the flanks of the wedge or key. Secondly,

' this wedge or key consists of one or more parts which serve for uniting said flanks and therewith for retaining the shape of the wedge as a whole, which latter parts may therefore be called bridges. This distinciJlOIllbGtWGGIl the several parts of the slot' key 1s more fully explained by referring to F1gures 17 of the accompanying drawing.

In Flg. 1 a cross section 0f the 3 slot key is shown and in particular itis indicat-' ed in this figure how the lateral magnetizable ribs or flanks of the key affect the lines of force; V i i Fig. 2 shows a ment in Fig. l; Y

Figs. 3 andt' and 5 to. .7 show modificatlons of the forms of the key adapted to be inserted into the slotsof dynamo-electrical machine elements according to the inven- 1310115 Fig. 8 showsthe manner of placing the key in'its seat, and- '1 c Fig. 9 shows a particularly: advantageous form of the key. i

In F igs. 1 and 2 a part of the slotted iron body or core l iisindicatedas having a slot N between the two-'eteeth Z, and Z Fig. 2 is a view of the surface of said slotted body K and Fig. 1 a section in the plane of Fig. 2. v The slotsN is what is called an plan view of'the arrangeopen slot, for the width n of its -.crossi-s eetion (Fig. 1) at'the surfaceof K is not smaller than the width 'n at the bottom of theslot'. The slot-is" closed by'a wedge or" key which is inserted into the slot after the winding has been mounted therein. In

grooves 7", and 1, preferably of wedge-e shaped cross-section which'serve fori'receiv ing the wedge or key' V, thus forming a I seat for firmly retaining the same in positlon. The wedge V properconsists of the flanks'e and a, and the bridges 7),, 6 ,6 h

keeping said flanks in 'positionffour such bridges'being shown in the drawing The number of these bridges of course maybe chosen as desired, also only one bridge may be employed. In F ig. l I have shown how the lines of force I", f pass from the teeth Z Z through the flanks a a of the wedge or key V and how the surface of the teeth is increased thereby for the passage of the magnetic lines of force.

The flanks of the wedge or key must be of magnetizable material in order to serve their purpose, while the bridges are used only for mechanical purposes and therefore do not need to be of such material. These bridges may however be of magnetizable material and may be connected with the flanks in any manner. In case of a wedge or key which is made from laminated iron sheets, such as represented in Figs. 3 and 4, the. middle parts of the laminae, for instance that portion within the range of the lines a and 4:, shown in the drawing, ma be regarded as individual bridges or all tiese parts together may be considered as a single bridge. With the wedge or key of the kind shown in Figs. 5 and 7, whereby the laminated flanks a and (1 are kept together by means of connection pieces of a shape according to' Fig. 6, the middle part I) of these connecting pieces will then have the function of said bridges.

According to my invention now at least the magnetizable flanks of the wedge or key shall be of laminated construction and at the same time the shape and material of the bridges shall be such that said bridges can be stretched by a proper tool, so that they will remain in stretched condition and that the flanks will firmly fit the grooves of the teeth. These bridges therefore must be of malleable material and must not be resilient, so that they will be readily deformable without again assuming their original shape, The malleability of the bridges according to my invention is utilized for fastening the wedge or key within the grooves provided on the upper part of the teeth and more particularly this is accomplished in the following manner The wedge or key is made of a width which is slightly smaller than the contour of said grooves, z'. 6., of its seat, so that the key may easily be inserted. Thereupon. the width of the key is increased by stretching the bridges, which'causes it to become firmly jammed into its seat.

Since the material of the bridges as above stated must be malleable, a wedge or key which is made of softyiron according to Figs. 3 and 4 will immediately satisfy this condition. In case of a wedge or key having non-magnetic bridges, such as for instance shown in Figs. 5, 6 and 7, brass, German silver or the like. is used for the bridges. Regarding the shape tobe chosen for the bridges according to my invention it is most advantageous to make the bridges somewhat arched, so that by exerting a proper pressure on them they will be stretched and will force the flanks to firmly fit into the grooves provided at the upper end of the teeth. It is also preferable, if bridges are used similar to those illustrated in Figs. 5, 6 and 7 to arch both their upper and lower faces in the same outward direction, because in this case the stretching of the bridges for fastening the same between the teeth can be accomplished in a very simple manner by hammer blows.

Fig. 8 represents my invention in the just mentioned modification applied to a wedge or key of the kind shown in Figs. 5, 6 and 7. The bridges b of the wedge or key V, as seen from the front, are outwardly arched in the same direction on both their upper and lower faces. As shown in this figure the wedge or key will still be lying loosely within its seat after having been inserted in a direction,perpendicular to the drawing. The grooves r r, are usually lined with insulating sheets 71, and i such as for instance paper. For fastening the wedge or key the arched bridges b are stretched by a pressure or a hammer blow which is exerted thereon in the direction indicated by the arrow P. This will cause the flanks a arrows Q, B, so that they will be pressed firmly into the grooves r r Tam aware that it is known to employ laminated slot keys or wedges, and also to spread such keys or wedges into their seats. According to my invention the key for closing the slot is so constructed that at least the flanks are made from laminated material and that the key as a whole is spread into'the slot which results in the advantage that the insulating' sheets between the key and its seat (i '5 Fig. 8) may be chosen extremely thin. This insulation must be present in order to prevent eddy-currents from-being generated during operation in the ordinarily'laminated teeth of the. slotted dynamo body or element, if between the sev-.

accomplished. The insulation should be as thin as possible, in order that the magnetic lines of force in passing from the flanks of the wedge or key into the teeth of the slotted body shall meet as little resistance aspossible. If the key is driven into its seat from the side the insulation will be very heavily strained especially in case the key is made from laminatedmaterial, because the edges of the several laminae will act not unlike the teeth of a' file. The insulation would therefore have to be comparatively thick, If a key having solid flanks" is spread into the seats the pressure of the flanks will as a rule be received by. the several laminae of the teeth, which always project from-the others by reason of inevitable inaccuracies,

these places, the insulation againjmustbe comparatively thick. If however according to my invention a laminated key is spread into its seatjthe flanks will beabletofit the unevenness of the surfa'cesfof the' seats, becausethe flanks are to a certain extent pliable. This pliability is caused by the fact that the several laminae can be displaced relatively to each other and is duetoa certain extent to the flexibility of the rivet holding the several laminae togethenand to the fact that the several bridges may be stretched or deformed to a different extent. The pliability of the wedge or key effects a more uniform distribution of the pressure upon the insulation and thereby does away with the necessity of using a heavier insulation between the key and its seat, such as in the case of solid flanks. The flexibility of the laminated wedge or key has further the advantage that when the key is spread into its seat it is very well secured against falling out of the slot, for a sort of toothed connection between the key and its seat is made by the alternate recesses and projections which mesh with each other and thus serve to safely hold the key in position.

The fact that the insulating sheets are very thin has a further advantage in that the thin sheets do not even up the slight projections and recesses of the key and its seat, so that the aforementioned effect of the toothed connection will come more fully into action. When stretching the outwardly arched bridges 5, such as has been described on the hand of Fig. 8, the flanks a and a make a small rotary motion in the grooves 13 and 1' During this motion the insulating sheets i, and 2' may be injured by sharp edges occurring at the flanks of the key. In order to prevent this the profiles of the flanks and seats are rounded off and more particularly at least at those points which will possibly slide upon one another during the operation of spreading the key into its seat. An example of the rounded edges is shown in Fig. 9, the rounded off points being shown at 0 and 0 The rivets for keeping the laminae of the flanks together are made from a tough material, such as tombac, bronze, German silver or the like. The cross-section of these rivets is preferably of oblong shape, as shown in Figs. 3, 5 and 9. The heads of the rivets are most conveniently formed by simply bending down the projecting ends of the rivet, shown in Fig. 8. The oblong crosssection of the rivet in the first place prevents a rotation of the several laminae relatively to each other and of the flanks relatively to the bridges in case a form is given to the key according to figs. 5, 6, 7 and 8. Besides,

lines dff forc'e inthe flanks, as compared with rivets of round cross-section having the. same mechanical strength. In additionto this the further advantage is secured that the bending strength of the rivet is increased in that direction in whichit is strained when the 'key is spread into its seat. v V Having thus described 'my -invention I claim new 'and desire to secureby Letters Patent of the United'statesz 1 A wedge'or keyfon the slots ofdyna mo-electric machine elements, consisting of laminated magnetizable flanks, and bridges connecting said flanks, said bridges being of malleable material, whereby said wedge or key may be spread into its seat by deforming said bridges, substantially as described and for the purposes set forth.

2. A wedge or key for the slots of dynamo-electric machine elements, consisting of laminated magnetizable flanks, and bridges of a malleable material interposed between said flanks, said bridges being originally arched in outward direction on the ends of said wedge or key, whereby said bridges may be deformedafter insertion of the key to keep the same firmly in the slot.

3. A wedge or key for the slots of dynamo-electric machine elements, consisting of laminated magnetizable flanks, and bridges of malleable materialinterposed betweenv rivets passing through the length of said 7 4. A wedge or key for the slots of dynainto its seat by deforming said bridges, and

rivets of oblong cross-section passing through the length of said flanks.

5. A slot key, comprising in combination, laminated magnetizable flanks and comparatively narrow deformable bridges connecting said flanks. V

6. Aslot key, comprising in combination, laminated magnetizable flanks and comparatively narrow deformable curved bridges connecting said flanks.

7 A slot key, comprising in combination, laminated magnetizable flanks and deformable bridges connecting said flanks, said key being originally arched.

8. A slot key, comprising in'combination, laminated magnetizable flanks and deformable bridges connecting said flanks, said bridges being shaped so as to spread said flanks apart upon being deformed;

9. A slot key, comprising in combination,

laminated magnetizable flanks, rivets passing through and holding said flanks to-' gether, and comparatively narrow curved bridges connecting said flanks, said bridges being. shaped so as to spread said flanks apart upon being deformed, V

10. A slot key, comprising in combination, laminated magnetizable flanks, rivets of oblong cross-section passing through and holding said flanks together, and comparatively narrow curved portions connectlng said formed.

In testimony whereof I have hereunto set my signature in the presence of two subscribing witnesses.

, MAX JOSEPH ILG.

' Witnesses: I Y

GEoRG WURZNER, J. MCNALLY.

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