US2856896A - Fixture for confining laminations during fusing of glass thereto - Google Patents

Description

' Oct. 21, 1958 L. MAKQUS FIXTURE FOR CONFINING LAMINATIONS DURING FUSING OF GLASS THERETO Filed July 30, 1954 FIG. 4..

FIG.3.

' INVENTOR. Lawrence Makous ATTORNEYS.

United Stts atent FIXTURE FOR CGNFINING LAMINATIONS DG F USING OF GLASS THERETU Lawrence Makous, Milwaukee, Wis, assignor to A. 0. Smith Corporation, Milwaukee, Wis, a corporation of New York Application July 30, 1954, Serial No. 446,729

4 Claims. (Cl. 118-503) This invention relates to an apparatus or fixture for effecting a high temperature fusing or baking of a winding slot insulation such as glass or ceramic enamel to an electromagnetic laminated core member.

In many applications of electromagnetics, a core mem her is employed with the windings disposed in slots on the core member. The windings are insulated from the core by a suitable slot insulation which prevents contact between the windings and the core member.

A particularly advantageous slot insulation is disclosed in the co-pending application of Neil Atherton, entitled Glass-Lined Stator Core. Serial No. 387,477, filed October 21, 1953, now abandoned, and assigned to a common assignee with the present application. As disclosed therein, a glass coating or the like is fused to the surfaces defining the slot and provides the required slot insulation.

Where the core member is formed of a plurality of laminations, the laminations tend to buckle and destroy the core member during the fusing of the glass coating due to the high temperatures of 1600-1700 F. required to fuse the coating. To avoid the buckling of the laminations, suitable pressure is necessarily applied to the stacked lamination.

In core members such as for the rotor or stator of a motor, the windings are in the form of coils with the sides of each coil lying in spaced slots and the ends of thecoil lying circumferentially around the end surfaces of the core member. Therefore, it is also advisable to glass coat the end surfaces of the core member adjacent the slots to provide complete insulation of the winding from the core member.

In accordance with the present invention, pressure is applied to the laminated core member by a series of pins disposed at critical points at the ends of the core member to prevent buckling and still permit the glass coating of the outer surfaces of the core member. Pressure is applied in any manner, such as by heavy plates or blocks to which the pins are secured. Although at the points of contact between the core member and pins, no glass coating is obtainable, the positioning of the pins is such as to prevent interference with a satisfactory slot and end surface insulation.

For purposes of illustration, the invention is shown in connection with an annular magnetomotive core member having winding slots for a distributed field winding.

The drawing furnished herewith illustrates the best mode, presently contemplated, for carrying out the invention as hereinafter described.

In the drawing:

Figure 1 is a sectional view of a laminated core member disposed between a pair of pressure plates;

Fig. 2 is a side elevation of one of the plates shown in Figure 1;

Fig. 3 is a plan view of one of the plates;

Fig. 4 is a plan view similar to Fig 3 with the core member thereon;

Fig. 5 is an enlarged view of a portion of Fig. 4 with a part thereof broken away;

Fig. 6 is an enlarged view of a portion of Figure -1 showing the disposition of the pressure pins and the end surface of the core; and

Fig. 7 is an enlarged sectional view taken on line 7-7 of Fig. 5.

Referring to the drawing and particularly Figure l, a conventional stator core 1 is illustrated consisting of a plurality of annular laminations 2 secured together by suitable means such as rivets 3. The laminations 2 have inwardly extending teeth 4 which are in alignment to form a plurality of winding slots 5 disposed about the inner periphery of the core. The method of constructing the core 1 is any of the conventional and known The stator core 1 is glass coated on the surfaces 6 defining the slots 5 and on theaxial end surfaces of the core as at 7 to provide a complete Winding insulation.- As shown more clearly in Fig. 5, the axial end surfaces of the core are glass coated in the teeth portion and also somewhat radially outwardly of the slots to prevent the winding which extends from one slot to another from shorting against the core. Further, as more clearly shown in Figs. 6 and 7, the axial end edges 8 of the slots are rounded to permit fusing of the glass thereto.

To prevent buckling of the laminations, during the. fusing of the glass coating the core 1 is disposed betwee a pair of pressure plates, as shown in Figure 1.

As shown in Figs. 2 and 3, each pressure plate consists of, in general, a pressure block 9 having two sets of pins 10 and 11 extending an equal distance therefrom and in a direction axially of the core when assembled therewithas will be described.

The pressure block 9 is shown as a flat, square block of any heavy material, for example, iron. The block 9 provides a common support for the pins 10 and 11 and also provides a source of pressure, as hereinafter de. scribed. 4

The set of pins 10 consists of four identical pins, dis-, posed one to each side of the block and at 90 to each other. The pins 10 are disposed adjacent the outerperiphery of the block 9 such that the pins bear upon the radially outer end surface of the stator core, as shown in Fig. 4.

The set of pins 11 consists of a series of pins equal in number to the teeth 4 on the stator core. The pins 11 are disposed centrally of the pins 10 with the center points of the pins 11 tracing a circle having a diameter equal to the internal diameter of the stator. The peripheral spacing of the pins 11 is equal to the spacing of the teeth of the stator, such that with the plate and stator assembled, as in Figure l and Fig. 4, each tooth has a single pin 11 engaged therewith. i

To facilitate assembly of the stator and the plates, a generally cross-shaped alignment mandrel 12 is secured to the flat pressure block 9 as by screws 13 which extend through a central opening in the mandrel 12 and thread into the block 9. The mandrellZ is of a thickness in excess of the length of the pins 10 and 11 and the points of the cross are undercut adjacent the block 9 providing the lips 14 which abut against the inner surface of core 1 axially inwardly of the pins 11. The lips 14 are provided with a circumferential surface complementing the internal curvature of the stator core such that the mandrel 12 fits snugly into the stator core. In this manner, the pins 11 are radially aligned, with the centers of pins 11 lying on the inner edges of the teeth at the axial face of the core, and the pins 10 are disposed against the axial face of the main body of the stator time.

An index lug 15 extends from each block 9 and is received by a corresponding recess 16 on the periphery of 3 the stator core. With the lug in the recess, the pins 11 are'each aligned with a tooth 4 of the stator core.

The invention is carried out in the following manner:

Laminations 2 are first assembled and secured together by rivets 3' and all lamination edges to receive a glass ccia tingare rounded; A suitable glass frit isapplied to the slot surfaces 6 and the end surfaces 7 of the stator core 1 The stator core 1 in an upright position is then placed on a pressure plate with the alignment mandrel 12 extending into the stator and the index lug 15 extending into the recess" 16.- The; pins 11 then engage the tips of the teeth and the pins 10 engage the surface of the end laminationr adiall y' outwardly of the slots 5 to hold the pressure plate- 9'in-spaced'relation' to the stator core.

Thereafter a pressure plate is located on top of the vertically extending stator core 1 with an index lug 15 disposed in recess 16 andrnandrel 12 inside the core and with pins 10 and 11 engaging the core as described with respect to the first plate, and the assembly is' placed vertieally in a suitable furnace for fusing the glass frit to the core surfaces 6 and 7 at temperaturesof 1600 to 1700 F.

The plates or blocks 9 exert sufficient pressure through the pin's by means of the weight of the upper plate or block to prevent the laminations from buckling during firing of the glass. The pins hold the plates in spaced relation to core 1 arid-allow glass coating of the end-surfaces 7 of the core;

The points atwhich the pins 11 contact the stator core are not glass coated. This is permissible as in winding the core in the conventional manner there is no danger of the winding contacting these points and being shorted to the core,

After the glass frit is fused to core 1, the core is removed frorn between the pressure plates.

The invention provides a novel fixture for confining a stator core while a glass coating is being fused thereto at high temperature to prevent buckling of the laminations.

Various modes of carrying out the invention are con templated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. Ina pressure applying fixture employed during fusing i electrically insulating material fusable at high temperatures to a laminated magnetomotive core having a plurality of slot defining teeth to prevent the teeth from buckling under the high temperatures, a plurality of pins extending axially of the core with eachpin adapted to engage the end face of a tooth of the core immediately adjacent the tip of the tooth, means associated with said fixture to dispose said pins in radial alignment with the teeth of the core, and a pressure block connecting said pins and removed from the axial face of the core to exert a force on the laminations during the fusing operation that prevents the laminations from buckling and permits coating with the insulation material substantially the entire axial face ofthe core.

2. In a fixture adapted to confine a laminated annular magnetomotive core having a plurality of circumferentially spaced winding slots on the inner periphery during a fusing of a vitreous enamel insulation at a high temperature to the surfaces defining the slots and to the adjacent end surfaces, a pressure block as a source of pressure, a series of circularly spaced pins equal in number to the teeth on said core member, said pins extending from said block and being disposed with each pin aligned with a tip of a single tooth to prevent interference with the fusing of insulation to the end surfaces, a plurality of other pins extending from said block and adapted to engage a surface of said core member radially removed from said teen to prevent interference with the fusing ofinsulation to the end surfaces, an alignment mandrel extending from said block and having a flange equal in diameter to the internal diameter of said core to radially align said first named pins and the tips of the teeth, and an index pin protruding from the block and adapted to mate with a recess in said core to circumferentially align each of said first named pins with the tip of a single tooth.

3. A fixture for confining a laminated electromagnetic core during a fusing of a glass insulation at high temperatures to the surfaces defining the winding slots and to the axial and surfaces adjacent the Winding slots, which comprises a pressure plate, a series of pins extending from said plate and being equal in number to the slot teeth defining the Winding slots, said pins being disposed on the pressure plate in a configuration complementing the tip portion of the teeth for engaging the latter during the fusing operation to confine the laminated core and prevent buckling of the lamination during the fusing operation, a spacer protruding from the plate for engaging the end surface of the core at a point radially removed from the winding slots to confine the laminated core and prevent buckling of the lamination during the fusing operation, a mandrel extending from said plate and adapted to cooperate with the core to effect a radial alignment of the pins and the tips of the teeth, and an index for circumferential alignment of the pins and the teeth.

4. A fixture for confining an annular laminated magnetomotive core during a fusing of a slot insulating mate rial at high temperatures to the surfaces of the teeth defining the winding slots on the inner periphery of the core and to the axial end surfaces of the teeth and the adjacent axial end surface, which comprises a pressure block of heavy material for providing the confining pressure on the laminated core, a series of circularly spaced pins extending from the block for engaging the radial innermost end surfaces of the teeth to prevent buckling of the laminations during the fusing-of the slot insulation, a second set of pins extending from the pressure block for engaging the end surface of the core radially outwa'rdly of the insulating material to prevent buckling of the lamination during the fusing operation, and a mandrel attached to said plate and adapted to engage the inner circumferential surface of the core to dispose the pins in radial alignment with the teeth of the core.

References Cited in the file of this patent UNiTED STATES PATENTS Re; 4,829 Ray Mar. 26, 1872 220,681 Doyt Oct. 14, 1879 2,065,526 Huttinger Dec. 29, 1936 2,665,659 Ogle -o. Jan. 12, 1954

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