“Apparatus and method for manufacturing coil members for cores of dynamo electric machines by bending”.
The present invention relates to apparatuses and processes adapted to produce coil members having a fork-like shape, or different shapes, by bending at least one electric conductor.
Once formed, said coil members are inserted into slots of a core of an dynamo electric machine. Fork-shaped coil members are commonly called “hairpins” in the industry. Other shapes may have an undulated configuration, as described in European publication EP1372242.
The magnetic core in which the coil members are inserted may be, for example, a stator for an electric motor or for an electric generator.
The hairpin normally has two straight legs connected together by a bridge-like transversal part. As a whole, the hairpin somewhat looks like an upside-down “U”, with the bridge having a cusp-like shape. Each leg has one free end for inserting the hairpin into the slots of the core. The insertion into the slots is done by passing the free ends of the legs through the longitudinal entrances of the slots and by sliding them past the opposite side of the core, until the legs protrude outwards to a certain extent.
According to the prior art, the hairpin is produced from a conductor having a rectangular or circular cross-section. More in detail, the conductor is cut into straight segments of a predetermined length; each straight segment is bent around a mould to take a temporary “U” configuration.
The temporarily formed legs are then inserted into the slots of two concentric rings, which can rotate relative to each other in opposite directions. With the legs inserted in the rings, a rotation in the opposite direction will subject the hairpin to a definitive deformation, thus giving the hairpin its final configuration, i.e. with the legs spread apart by the pitch required for inserting them into the core slots and with the head deformed accordingly.
In a hairpin production process of common use, after being cut, the straight segment is bent around a first mould to obtain an intermediate hairpin configuration in a plane. The head of the intermediate configuration is then pressed against a second mould to obtain the definitive configuration, wherein the legs are in the correct positions for insertion in the slots. Therefore, this is a process that requires deforming the conductor by pressing it onto suitable moulds.
The apparatuses of common use in the art operate automatically and are not easily adaptable for changes in the geometry of the coil members.
Furthermore, the automatic operations involve pressing the conductor against moulds, and this often places high stresses on the conductor and on the insulation thereof, leading to a high risk of damaging the latter.
It is therefore one object of the invention to manufacture coil members while minimizing the risk that the conductor gets damaged.
It is another object of the invention to produce coil members by using a simplified solution.
It is a further object of the invention to manufacture coil members whose configuration can be changed by means of a programmable solution.
It is yet another object of the invention to manufacture coil members having precisely bent portions, so as to optimize the placement thereof into the spaces available in the cores of dynamo electric machines.
Said objects are achieved by the present invention through an apparatus and a method according to the appended independent claims 1 and 15 for manufacturing a coil member to be inserted into the slots of a core of an electric dynamo machine.
Further preferred and advantageous features of the invention are set out in dependent claims.
These and other objects and advantages of the invention will become apparent from the following detailed description, which is only provided by way of non-limiting example, with reference to the annexed drawings, wherein:
a shows a detail of a substitutive unit applicable to the solution shown in
a is a view along the direction 2a of
a is a view along the direction 10a of
a is a view along the direction 11a of
a is a view along the direction 12a of
a is a view along the direction 13a of
With reference to
The unit 11 unwinds the conductor 10 from a conductor magazine 11′, whereon the conductor was previously wound to form a reserve coil.
The cross-section of the conductor 10 in the magazine 11 may be circular, and unwinding takes place by aligning the longitudinal axis of the conductor 10 with the axis 100′ of a feeding path.
The path may be straight, i.e. parallel to the axis 100′, with a feeding direction 10′, as shown in
The motion of the conductor 10 along the path, and therefore the feeding of the conductor 10 along the path, may occur through a push/pull action exerted onto the conductor in the unit 16, where motorized belts 16a and 16b press against the conductor in the feeding direction 10, as shown in
The unit 13 carries out the transformation of the conductor's cross-section, e.g. from a circular cross-section to a rectangular cross-section (or another cross-section with plane sides).
Upstream of the station 13 there is a station 12 for straightening the conductor 10, where the conductor is forced to slide along the feeding path 100′.
In the station 12, the conductor 10 slides through idle rollers 12′, whose surfaces engage the conductor to force it to follow the feeding path.
More in detail, while passing through the rollers 12′ the conductor 10 engages those surfaces of the rollers 12′ which are arranged laterally and tangential with respect to the feeding path, as shown in the elevation view of
In the unit 13 there are a series of pairs of rollers 13a,13b,13c,13d. Each roller of one pair is shaped in accordance with the deformation print to be created on one side of the conductor. The print is created by engaging the roller on the side with a certain predetermined pressure.
Engagement occurs in a direction transversal to the axis 100′ of the feeding path.
The rollers of one pair 13a,13b,13c,13d rotate with respect to each other in a synchronous and opposite manner. Moreover, the rotation of the rollers can be synchronized with the rotation of the belts 16a and 16b through the controller 15.
The transversal pressure applied by the rollers deforms the cross-section of the conductor 10, from circular to rectangular in the case shown in
More specifically, the roller pairs 13a,13b,13c,13d are mutually arranged at 90°, so that their profiles are oriented according to a succession of deformations in the following order: the conductor's sides are deformed for a first time by the pair 13a; then the conductor's top and bottom are deformed for a first time by the pair 13b; subsequently the conductor's sides are deformed for a second time by the pair 13c; finally, the conductor's top and bottom are deformed for a second time by the pair 13d.
The unit 14 downstream of the unit 13 along the feeding path is capable of providing information useful for measuring the conductor length being fed from the moment when a conductor's cut end passes by the photocell 17 positioned after the unit 14. In fact, the photocell 17 can signal the presence of a cut end of the conductor 10, and can therefore start the counting of the length of the conductor being fed to the bending unit 18. The counting is done by the control system 15, which uses the length passage information transmitted by the measurement wheels in the unit 14 and the count start signal transmitted by the photocell 17.
The bending unit 18 is capable of bending the conductor in order to have it take the desired coil member configuration, e.g. the coil members shown in
With reference to
The feeding axis AC′ is a theoretical reference that can be considered to coincide with the axis of the feeding path 100′ of the conductor 10, as shown in
The crown gear 31 is mounted integral with one end of the support member 20, as shown in
With reference to
The central perforated part of the support member 20 houses the tube 21. The slide bushings 21′ are interposed between the tube 21 and the slide member 22. In this way, the slide member 22 is supported by the tube 21 and can move on the bushes 21′ in the directions T or T′, i.e. parallel to the axis AC′ and to the axis 100′, with respect to the tube 21 when the screw portion 29′ is turned by the motor/pinion 200.
The tube 21 is secured to the frame 30 by means of the fastening plate 25. As shown in
The bearings 21″ are mounted between the support member 20 and the tube 21 to allow the rotations R and R′ of the support member 20 around the axis AC′ with respect to the tube 21, which is secured to the frame 30 through the plate 25.
A second slide member 23 is adapted to slide on the slide member 22 (see
The motion in the directions X and X′ takes place through the rotation of the gear 41, which meshes with the rack 37 secured to the second slide member 23, as shown in
The member 38 is movable in the directions X and X′ on the second slide member 23. The member 38 comprises a first rack portion 38′ and a second rack portion 38″ (see
The motion of the member 38 in the directions X and X′ takes place through the rotation of the gear 45, which meshes with the rack portion 38′. The gear 45 is fitted to the end of the shaft 65, which is adapted to rotate on the slide element 22. The shaft 65 receives the shaft 66 in a bore 65′ at its end, as shown in
The conductor bending tool 50 (see FIGS. 3,4,5 and 6) comprises at least one of the pins 51 and 52 integral with the base 53.
As shown in
The shaft 54 is slideable in the directions Z and Z′ in the central perforated part of the member 56, which is integral with the second slide member 23, and is therefore slideable in the directions Z and Z′ with respect to the second slide member 23. The directions Z and Z′ are perpendicular to the axis AC′, as shown in
The member 56 is supported on the bearings 55 mounted in the support bell 57 (see
The movements of the member 38 on the second slide member 23 in the directions X and X′ as described above cause the shaft 54 to rotate, bringing along the pins 51 and 52 of the rotation RO, or of the opposite rotation RO′, on the second slide member 23, i.e. around an axis RZ (see
In fact, the key 60 on the shaft 54 engages a seat 60′ in the central perforated part of the member 56. The seat 60′ is parallel to the axis 54′. Therefore, rotation is transmitted from the member 56 to the shaft 54, and the shaft 54 is allowed to slide parallel to the axis RZ.
The axis RZ can be considered to be a reference axis perpendicular to the axis AC′. The axis of the shaft 54′ is parallel to the axis RZ and can be considered to coincide with the axis 54′, as shown in
The drive cylinder 61 is secured to the surface 23′, as shown in
When the cylinder 61 is actuated, the shaft 54 is therefore moved in the directions Z and Z′, parallel to the axis RZ, and as a result also the pins 51 and 52 can move in the directions Z and Z′, parallel to the axis RZ.
The movements of the member 38 on the second slide member 23 in the directions X and X′ cause the shaft 54 to rotate, bringing along the pins 51 and 52 on the second slide member 23, around the axis RZ on the second slide member 23. Therefore, the pins 51 and 52 are supported on the second slide member 23 to rotate around the axis RZ of the rotations RO and RO′.
The possible movements of the pins 51 and 52 are summarized in
Through movements T and T′ of the slide member 22 generated by the motor/pinion 200, the axis RZ translates perpendicular to the plane containing
Through the movements of the second slide member 23 in the directions X and X′ with respect to the slide member 22, generated by the motor/pinion 400, the axis RZ translates transversally to the axis AC′. Consequently, the same translation movement is made by the pins 51 and 52.
Through the rotations of the support member 20 around the feeding axis 100′, generated by the motor/pinion 500, the axis RZ rotates around the axis AC′ of the opposite rotations R or R′, in that the surface 23′ rotates in the same manner around the axis AC′. Consequently, the same rotational movement R or R′ is made by the pins 51 and 52.
Through the actuation of the cylinder 61, the pins 51 and 52 are moved perpendicularly towards or away from the axis AC′. In this case, the pins 51 and 52 translate parallel to the axis RZ.
Through the movement of the member 38 on the second slide member 23 in the directions X and X′, generated by the motor/pinion 300, the pins 51 and 52 perform rotations RO or RO′ around the axis RZ.
For clarity and simplicity, in
With reference to
To reach this position, the pins have been rotated by the rotations RO or RO′ around the axis RZ, translated in the direction X′, and rotated around the axis AC′ by a rotation R with respect to the position of
The bending of
This bending movement of the pins 51 and 52 is obtained by using a combination of rotation RO around the axis RZ and movement of the pins 51 and 52 in the direction X. During these movements, the pins apply a transversal force onto the conductor 10 in order to bend it as indicated by the continuous line of the conductor 10 in
The bending shown in
The bending of
The bending of
In summary, the pins 51 and 52 have been translated in the direction T′, translated in the direction X, rotated by the rotation RO around the axis RZ, and rotated by the rotation R around the axis AC′.
The bending shown in
The torsion bending of
The coil member of
The bending unit 18 creates the bend that characterizes the hairpins of
For the hairpin of
In a second step the bend portion 131 is made, which consists of a curve and a torsion obtained, for example, by applying the principles of
In a third step the bend portion 132 is made, which consists of a gentler curve obtained, for example, by applying the principles of
In a fourth step the bend portion 133 is made, which consists of a curve and a torsion obtained, for example, by applying the principles of
The other portions 134, 135, 136 and 130′ that complete the hairpin are made in a similar manner through an appropriate combination of the bending operations of
As regards the coil member of
In one embodiment of the present invention, the bending tool 50 comprises only one pin 51 or 52 for performing the bending operations described with reference to
Furthermore, simpler coil configurations may only require a bending obtained through the movement of at least one of the pins 51 and 52 in the direction X and X′; in this case, the solution will be limited to the transmission from the motor 400, i.e. crown gear 33, gear 36, shaft 44, gear 41, rack 37 and guide 39 for the member 23, whereas the members 22 and 23 will be integral with each other without having to mutually rotate or translate.
Other coil configurations may require the addition of the rotation R and R′ of the support 20 through the motor 500 and the crown gear 31.
Further configurations may require the addition of the translation T and T′ of the member 22 through the motor 200 and the screw portion 29′.
The above description of one specific embodiment has illustrated the invention from a conceptual viewpoint, so that others, by using prior-art techniques, will be able to modify and/or adapt said specific embodiment to various applications without further research and without departing from the inventive concept. It is therefore understood that any such modifications and adaptations will be considered to be equivalent to the exemplary embodiment described herein. The means and materials necessary for implementing the various functions described herein may vary without departing from the scope of the invention. It is understood that the expressions and terminology used herein are merely descriptive and hence non-limiting.
Number | Date | Country | Kind |
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TO2011A000435 | May 2011 | IT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2012/002055 | 5/14/2012 | WO | 00 | 11/15/2013 |