Apparatus and method for inserting flat wire conductors into the core of a motor stator

Abstract

An apparatus for inserting flat wire conductors (H1) into the core (1) of a motor stator comprises an insertion station (4) for receiving and positioning a stator annular core (1) having inner slots (2) with insulation sheets (3) received therein, and a winding gripper unit (21) with a gripper device (22) for gripping an annular array (H) of flat wire conductors (H1) from an area (23) of the apparatus and for inserting the array (H) of flat wire conductors (H1) into the slots (2) of the stator core (1) which is positioned at the insertion station (4). A core positioning platform (6) includes a flat annular support surface (16A) configured for receiving and supporting the stator core (1) in a proper position. An insulation sheet alignment device (64) is arranged below the core positioning platform (6) and comprises alignment pins (65) for alignment of the core insulation sheets (3). The alignment pins (65) is raised from a lowered inoperative position to an operative position in which the alignment pins (65) engage the slots (2) of the stator core (1) which is positioned on the annular support surface (16A). The alignment pins (65) hold the insulation sheets (3) in their proper position within the core slots (2) until the array (H) of flat wire conductors (H1) is inserted into the core slots (2).

Description

[0001] “Apparatus and method for inserting flat wire conductors into the core of a motor stator”

[0002] Technical field

[0003] The present invention relates to an apparatus for inserting flat wire conductors into the core of a motor stator, of the type comprising:

[0004] - an insertion station for receiving and positioning a stator core having inner slots provided with insulation sheets, e.g., sheets of insulation paper,

[0005] - a winding gripper unit for gripping an annular array of flat wire conductors from an inlet area of said apparatus and for inserting said array of flat wire conductors into corresponding slots of a stator core positioned at said insertion station.

[0006] Background

[0007] With the development of the automotive industry in the field of vehicles with new propulsion systems, the market demand for electric and hybrid vehicles is greatly increasing. An electric propulsion system, as a component of an electric or hybrid vehicle, has a significant impact on power, economic efficiency, comfort, safety, and the service life of the vehicle. As a core of the electric propulsion system, the performance of an electric motor directly determines the performance of the vehicle to a great extent. The step of inserting the conductors into the slots of the stator core is particularly critical due to the need of enabling a precise positioning of the conductors into the stator slots without any risk of damage or deformation of the insulation sheets arranged within the slots. In the most conventional production methods, the conductors are manually pressed into the stator core, which, of course, results in a low production efficiency. Moreover, the insertion process cannot guarantee the stability of the product, due to the risk of an irregular deformation and / or misalignment of the conductors and the insulation sheets, which affects the quality of the stator windings.

[0008] There is therefore a strong need for improvements in this field.

[0009] Summary

[0010] The main object of the present invention is to overcome the deficiency of the prior art by providing an apparatus and a method for automatically performing the operation of inserting flat wire conductors into the slots of a stator core, while ensuring precise and proper positioning of the conductors, without any risk of damage, deformation or misalignment of the insulation sheets during the insertion process.

[0011] In view of achieving the above indicated object, the present invention provides an apparatus for inserting flat wire conductors into the core of a motor stator, comprising:

[0012] - an insertion station for receiving and positioning a stator core having inner slots with insulation sheets received therein,

[0013] - a winding gripper unit with a gripper device for gripping an annular array of flat wire conductors from an inlet area of said apparatus and for inserting said array of flat wire conductors into the slots of a stator core positioned at said insertion station,

[0014] - said apparatus being characterized in that said insertion station comprises:

[0015] - a core positioning platform, including a flat annular support surface configured for receiving and supporting the stator core in a proper position,

[0016] - an insulation sheet alignment device arranged below the core positioning platform and comprising an array of pins for alignment of the core insulation sheets, said array of alignment pins being vertically movable between a lowered inoperative position and a raised operative position, in which the alignment pins project upwardly from said core support surface, for engaging the slots of a stator core which is positioned on said annular support surface,

[0017] - so that when a stator core is received on said annular support surface, the array of alignment pins can be moved from its inoperative lowered position to its operative raised position, in which the pins are received within the core slots, thereby holding the insulation sheets in their proper positions within the core slots, until when the array of flat wire conductors is inserted into the core slots.

[0018] According to a further preferred feature, said core positioning platform includes:

[0019] - a support ring defining said flat annular support surface which is configured for receiving and supporting the stator core, said support ring including an annular inner portion with a plurality of slots, - a reference element configured to engage a cooperating cavity of the stator core for locating the stator core in a proper position on the annular support surface, with the slots of the stator core being properly aligned with the slots of said support ring.

[0020] Another preferred feature of the invention lies in that the annular support surface of said support ring has holes distributed along the circumferential extension of the support ring, configured for receiving a flow of pressurized air, for enabling obstruction of said holes by the stator core to be checked, as a sign that the lower surface of the stator core is correctly in contact with the flat annular support surface of the support ring.

[0021] In a preferred embodiment, said insertion station further includes:

[0022] - a core locking column having an upper locking head projecting upwardly from said annular support surface, so that the stator core, which is positioned on said annular support surface, surrounds said upper locking head,

[0023] - wherein said upper locking head is provided with radially movable locking supports which can be moved outwardly to engage and hold an inner surface of a stator core which is positioned on said support surface,

[0024] - wherein said upper locking head is also provided with engagement members configured for engaging a lower docking head of said winding gripper unit, and

[0025] - wherein said winding gripper unit comprises a guiding column for said gripper device, the gripper device being vertically movable relative to the guiding column, and

[0026] - wherein a lower end of the guiding column defines said lower docking head to be engaged by said engagement members of said upper locking head, so that said guiding column of the winding gripper unit can be connected to said core upper locking head of the core locking column, whereupon the gripper device of the winding gripper unit is configured to be lowered relative to the guiding column, to insert an array of flat wire conductors gripped by said gripper device into the inner slots of the stator core which is positioned on said annular support surface, while said array of alignment pins is being lowered and withdrawn from the slots of the stator core. Also preferably, said radially movable locking supports for holding the stator core and said engagement members for engaging the lower docking head of the winding gripper unit are driven by a single common actuator, through respective mechanical transmissions.

[0027] The invention is also directed to the insertion method implemented by means of the above-described apparatus.

[0028] Brief description of the drawings

[0029] Further features and advantages of the invention will become apparent from the following description, given purely by way of example with reference to the accompanying drawings, in which:

[0030] - figure 1 is a diagrammatic perspective view of a core of a motor stator with inner slots provided with sheets of insulation paper received therein,

[0031] - figure 2 is a perspective view of a portion of a preferred embodiment of the apparatus according to the invention, in a first operating condition,

[0032] - figure 3 shows the embodiment of figure 2 in a subsequent operating condition,

[0033] - figure 4 shows the embodiment of figures 2 and 3 in a subsequent operating condition,

[0034] - figure 5 shows a stator core received on a core supporting platform of the apparatus of figures 2-4,

[0035] - figure 6 shows the supporting platform of figure 5, at an enlarged scale, with the stator core removed,

[0036] - figure 7 shows a detail of the apparatus of figure 5, at an enlarged scale,

[0037] - figure 8 shows a detail of the apparatus of figure 6 at an enlarged scale and partially in cross-section,

[0038] - figure 9 shows a further detail of the apparatus of figure 6, at an enlarged scale and in cross-section,

[0039] - figure 10 is a perspective view of the preferred embodiment of the apparatus according to the invention,

[0040] - figure 11 is a further perspective view at an enlarged scale of the apparatus of figures 1 and 10,

[0041] - figure 12 is a perspective view from below of a docking head provided at the lower end of a gripper guiding column of the apparatus of figure 11 ,

[0042] - figure 13 shows the docking head of figure 12 in a coupled condition on an upper locking head of the apparatus shown in figure 6,

[0043] - figure 14 is a perspective cross-sectional view of the upper locking head of the apparatus of figure 6,

[0044] - figure 15 is a perspective view of the actuator and driving transmission for operating the upper locking head of figure 14,

[0045] - figure 16 is a cross-sectional view of the unit of figure 15,

[0046] - figures 17, 18 are perspective views at an enlarged scale of details of the unit of figures 15 and 16,

[0047] - figures 19 and 20 are perspective views of an insulation sheet alignment device forming part of the apparatus of the invention,

[0048] - figure 21 shows an alignment unit forming part of the insulation sheet alignment device of figures 19, 20.

[0049] - figure 22 is an exploded perspective view of the unit of figure 21 ,

[0050] - figure 22A is a perspective cross-sectional view of a detail of the unit of figure 22,

[0051] - figures 22B and 22C are perspective views of the insertion station showing two different operating conditions of the insulation alignment device,

[0052] - figure 22D shows a detail of figure 22C at an enlarged scale,

[0053] - figure 23 is a perspective view of the winding gripper unit forming part of the apparatus according to the invention,

[0054] - figure 24 is a perspective view at an enlarged scale and in crosssection of part of the winding gripper unit of figure 23,

[0055] - figures 25, 26, and 27 show detail of the winding gripper unit of figure 24 at an enlarged scale,

[0056] - figure 28 is a perspective view showing a stage of the insertion process,

[0057] - figure 29 shows a subsequent stage of the insertion process,

[0058] - figure 30 is a cross-sectional view of a portion of the insertion station in a subsequent stage of the insertion process, and

[0059] - figure 31 is a perspective view at an enlarged scale showing a final stage of the insertion process. Detailed description

[0060] Figure 1 shows a core 1 of a motor stator having an annular body 1 A with a plurality of inner longitudinal slots 2 having their ends opening on the opposite flat end surfaces 1 B of core 1 . A sheet 3 of insulation material, e.g. , insulation paper, is received within each slot 2.

[0061] Figure 2 is a perspective view of a portion of an exemplary embodiment of the apparatus according to the invention (further portions of the apparatus being shown in further figures). Shown in figure 2 is an insertion station 4, including a frame 5 with a core positioning platform 6 configured for receiving and positioning a stator annular core 1 , which is provided with the insulation sheets 3 already arranged within its slots 2, as shown in figure 1 .

[0062] In the example of figure 2, the stator core 1 , which is to be transferred onto the core positioning platform 6, arrives at the insertion station 4 by means of a conveyor 7 of any known type. The conveyor 7 conveys a pallet 8 carrying the stator core 1 . Needless to say, the apparatus for transferring the stator core 1 to the insertion station 4 can be of any known type.

[0063] In the illustrated exemplary embodiment, the apparatus of the invention includes a first core handling unit 9 for transferring the stator core 1 from the conveyor 7 to the core positioning platform 6. In this example, the core handling unit 9 includes a gripper 10 with a number of gripper elements which can be moved outwardly, when gripper 10 is inserted within the central aperture of the stator core 1 , so as to firmly grip and hold the core (see figure 3). In this example, the gripper 10 is carried by a supporting bracket 11 carried by a slide 12 which is vertically movable on a carriage 13. Carriage 13 is movable horizontally along a cross member 14 carried by a frame 15 secured to the upper table of the frame 5 of the insertion station 4.

[0064] Figure 3 shows the stator core 1 while it is being transferred by the core handling unit 9 from the conveyor 7 to the core positioning platform 6.

[0065] Figure 4 shows the stator core 1 positioned onto the core positioning platform 6, after which it has been deposited by the gripper 10 of the core handling unit 9.

[0066] Figure 5 is a perspective view at an enlarged scale of the stator core 1 positioned on the core positioning platform 6.

[0067] As shown in figure 6, the core 1 is supported on an annular support surface 16A of a stationary support ring 16. Ring 16 has an outer portion defining the flat annular support surface 16A and an inner annular depressed portion having a plurality of slots 16B, whose function will become clear in the following.

[0068] With reference to figure 6, three angularly spaced holes 17 open on the flat annular support surface 16A. One of the holes 17 is shown in crosssection in figure 8. The holes 17 are in communication with a source of pressurized air (not shown). When a stator core 1 is positioned on the flat annular support surface 16A, the holes 17 are obstructed by the lower surface of the core 1 if the core 1 is properly positioned in contact with the flat annular support surface 16A of the support ring 16. Therefore, by checking the pressure in the line supplying pressurized air to the holes 17, it is possible to detect whether the stator core 1 is properly positioned. If not, air can escape from one or more of the holes 17, which condition can be detected.

[0069] Also, with reference to figure 5, the core positioning platform 6 has optical cells 18A, 18B to detect the presence of a stator core 1 on the core positioning platform 6, which condition enables the start of the process operations which will be described in the following.

[0070] With reference again to figure 6, the support ring 16 has an outer appendage 16C, whose position can be adjusted tangentially by means of a screw adjuster 19 so as to slightly vary the mounting angle of the support ring 16.

[0071] Also, with reference to figures 6, 7, the core positioning platform 6 is further provided with a key-like reference element 20 having a projection configured to engage one of a number of cavities 1 C of the core 1 (see figure 1 ) to locate the stator core 1 in a proper position on the annular support surface 16A, with the slots 2 of the stator core 1 properly aligned with the slots 16B of the support ring 16.

[0072] As shown in figure 9, the stator core 1 is supported on the support ring 16 so that the lower surface of the core 1 is in contact with the outer flat surface 16A of ring 16, while each insulation sheet 3 has its lower end projecting from the core in contact with the depressed inner annular surface of support ring 16, in which the slots 16B are formed. In this way, during the subsequent insertion operation, each insulation sheet 3 is prevented from being pressed down when the flat wire conductors are inserted into the stator slots.

[0073] Figure 10 shows a perspective view of the apparatus according to the invention. In figure 10, the insertion station 4 is shown, including frame 5 which supports the core positioning platform 6. For simplicity, figure 10 does not show the core handling unit 9 and the conveyor 7 of figure 2.

[0074] As shown in figure 10, the apparatus of the invention comprises a winding gripper unit 21 provided with a gripper device 22 and configured for gripping an annular array H of flat wire conductors from an area 23 of the apparatus and for inserting the array H of flat wire conductors into the slots of a stator core 1 positioned on the core positioning platform 6.

[0075] In the illustrated example, the area 23 of the apparatus is a station with a comb device 24 where an array H of flat wire conductors has been prepared. Preferably, the comb device provided at station 23 is of the type proposed in Applicant's international patent application PCT / CN2024 / 093916, not yet published at the date of the present application. The array H is comprised of a plurality of hairpins H1 (see figure 29) arranged in layers, each hairpin having two leg portions connected to each other by an upper bridge portion.

[0076] In the embodiment of figure 10, the winding gripper unit 21 includes a gantry-like support structure 25, including two columns 26 which support an overhead cross-member 27. The gripper device 22 of the winding gripper unit 21 is carried by a support bracket 28 connected to a slide 29 (see also figure 23). The slide 29 is vertically slidably mounted on a carriage 30 which is movable along the overhead cross-member 27.

[0077] Figure 11 shows the insertion station 4 and both units 9, 21 : core handling unit 9 is provided with the gripper 10 for transferring a stator core 1 onto the core positioning platform 6, while winding gripper unit 21 is provided with gripper device 22 for inserting an array of flat wire conductors H into the stator core positioned on the positioning platform 6. The structure and operation of the core handling unit 9 has been already described above with reference to figures 2-4. The structure and operation of the gripper device 22 of the winding gripper unit 21 will be described in the following, with particular reference to figures 11 and 23-27.

[0078] The gripper device 22 includes a guiding column 31 (figures 12, 13), an upper comb plate 22A, and a lower comb plate 22B vertically movable relative to the guiding column 31 (see also figures 23, 24).

[0079] The lower end of the guiding column 31 defines a lower docking head 32 (figures 12, 13) which is to be engaged by an upper locking head 33 (see figure 6) projecting upwardly from the core positioning platform, as will be described more in detail in the following.

[0080] With reference in particular to figure 23, the vertical movements of the guiding column 31 are controlled by an electric servo-motor 34 carried by the support bracket 28. The upper and lower comb plates 22A, 22B are supported by two further brackets 36, 37, respectively. Also support brackets 36, 37 are vertically slidably mounted on the carriage 30 of the winding gripper unit 21 .

[0081] The vertical movements of the support bracket 37 carrying the upper comb plate 22A are controlled by an electric servo-motor 38 carried by support bracket 28. The vertical movements of the support bracket 36 carrying the lower comb plate 22B are controlled by an electric servo-motor 39 carried by support bracket 37.

[0082] The structure and operation of the upper and lower comb plates 22A, 22B is known per se. Each comb plate includes a support annular plate on which a number of radial pushing elements 40 (see figures 24-27) are radially slidably mounted. The radial movement of the radial pushing elements 40 is controlled by a rotating ring 41 including a plurality of spiral slits engaged by cam followers 42 carried by the pushing elements 40 (see figure 26). A rotation of disc 41 of the upper comb plate 22A is controlled by an electric motor 43 through a crank transmission, while the rotation of disc 41 of the lower comb plate 22B is controlled by an electric motor 44, also via a crank transmission (see in particular figures 23, 24).

[0083] As shown in figures 25-27, when an array H of flat wire conductors H1 is gripped by the gripper device 22, the various layers (six layers in this example) of legs of the hairpin elements which are to be received within a same slot of the stator core are engaged between adjacent radial pushing elements 40 (see figure 25) and against the outer surface of ring portions 45 surrounding column 31. Ring portions 45 have cavities 45A within which the tips of the radial pushing elements 40 are received when the array H of conductors is clamped by the upper and lower comb plates 22A, 22B. Figure 27 shows the lower ends of the hairpin elements projecting from the lower comb plate 22B, as seen from below.

[0084] Figure 12 shows the lower end of the column 21 of the gripper device 22, defining the docking head 32 which is to be engaged by the upper locking head 33 (see figures 6 and 13) projecting upwardly from the core positioning platform 6.

[0085] With particular reference to figure 14, the locking head 33 projecting upwardly from the core positioning platform 6 is defined by the upper end of a locking column 46.

[0086] The upper locking head 33 is provided with radially movable locking supports 47 (only one of which is shown in figure 14) which can be moved outwardly to engage and hold the inner surface of a stator core 1 positioned on the core positioning platform 6 (see also figure 30). The upper locking head 33 is also provided with a number (three in this example) of engagement members 48 which are pivotally mounted on the upper locking head 33 around respective horizontal axes and which are configured to engage the docking head 32 at the lower end of the column 31 of the gripping device 22.

[0087] Figures 14-16 show the driving transmissions which actuate the locking supports 47 and the engagement members 48. In this example, both transmissions are controlled by a single actuator 49 (e.g., a pneumatic cylinder).

[0088] With reference to figure 14, the radial movement of the locking supports 47 is controlled by a single axially movable stem 50 having a wedge-like upper head 51 having inclined faces cooperating with mating surfaces at the inner ends of the locking supports 47.

[0089] The tilting movement of the engagement members 48 is controlled, via cam-like pin-and-slot couplings 52 (figure 14) by respective auxiliary stems 53. As shown in figures 15, 16, the auxiliary stems 53 are connected, through a connecting ring 54, to three stems 55 whose lower ends 55A (see figure 16) are connected to a plate 56 to which the stem 50 for operating the locking supports 47 is also connected. The vertical movement of plate 56 is controlled by the cylinder 49. With reference to figure 16, a spring 57 is mounted around each stem 53, and axially interposed between the connecting ring 54 and the fixed support structure of the unit.

[0090] Figure 17 shows a sensor 58 for detecting the operating position of the actuating cylinder 49 and a sensor 59 for detecting the operating position of the engagement members 48. The position of stem 50, which operates the locking supports 47, is controlled through the cooperation of a block 60 with upper and lower limit bolts 62, 63. The position of block 60 on stem 50 can be adjusted through nuts 61.

[0091] Referring to figures 19-21 , the insertion station 4 is also provided with an insulation sheet alignment device 64, which is arranged below the core positioning platform 6 (see also figure 2). The insulation sheet alignment device 64 comprises an array of pins 65 for alignment of the core insulation sheets 3 (see figure 1 ). The insulation pins are in form of straight rods arranged parallel to each other according to a cylinder-like arrangement around a central axis 66. The column 46 carrying the upper locking head 33 is arranged through the insulation alignment device.

[0092] The lower ends of alignment pins 65 are received within outer slots 67 (figure 22) of a star-shaped cylindrical ring 68. The lower end of each pin 65 is clamped inside a respective slot 67 of ring 68, between the bottom surface of the slot and an outer ring 69 which is secured to a base plate 70 by screws (not shown).

[0093] Referring to figure 22A, the alignment pins 65 are clamped between ring 68 and ring 69 by locking screws 70A which connect ring 69 to the pins 65. Anti-separation screws 71 A press the pins 65 against the bottom of slots 67, and adjustment screws 72A have their ends in contact with each pin 65.

[0094] Referring to figures 19, 20, the base plate 70 is carried by an upper table 71 forming part of a slide 72 which is vertically slidably mounted on a support frame 73. The vertical movements of slide 72 are controlled by an electric servo-motor 74 through a belt transmission 75 and a screw 76 driven by the belt transmission 75 and engaged within a nut rigidly connected to slide 72. Figure 20 shows two parallel vertical guide rails 77 carried by the frame 73, on which the slide 72 is slidably mounted.

[0095] The slide 72 carrying the alignment pins 65 is controlled so that the array of alignment pins 65 can be moved between a lowered inoperative position and a raised operative position (shown in figures 19, 20) in which pins 65 project upwardly through slots 16B of the support ring 16 of the core positioning platform (figure 6). In the raised operative position of the alignment pins 65, the pins 65 are engaged within the slots 2 of the stator core 1 positioned on the core positioning platform 6 so that each alignment pin 65 holds the insulation sheet 3 in a proper position within the respective slot 2. The table 71 has a central aperture (not visible in the drawings) to avoid interference with the column carrying the upper locking head 33.

[0096] The operation of the apparatus according to the invention is as follows.

[0097] In a first step (figure 2), a stator core 1 , with sheets 3 of insulating paper inserted into the slots 2 of the core, enters the insertion station 4 through the conveyor 7.

[0098] In a second step, the gripper 10 of the core handling unit 9 takes the stator core 1 from the pallet 8 on conveyor 7 (figure 3).

[0099] In a third step, the gripper 10 of the core handling unit 9 places the stator core 1 onto the core positioning platform 6 of the insertion station 4 (figure 4).

[0100] In this condition, optical cells 18A, 18B send the information on the presence of a stator core 1 on the core positioning platform to an electronic controller (not shown) of the apparatus. Holes 17 (figure 6) of the positioning platform 6 are supplied with pressurized air to check that the lower surface of the stator core is properly in full contact with the flat support surface 16A of the support ring 16 (figure 6). In this condition, a proper position of the stator core 1 is ensured by the engagement of the key-like reference element 20 within a cooperating cavity 1 C of the core 1 . As indicated in the foregoing, the support ring 16 has a depressed inner annular surface in which slots 16B are formed (figure 6) which also supports the lower ends of the insulation sheets 3 (figure 9) so as to prevent the paper sheets to be pressed downwardly during the subsequent stage in which the flat wire conductors are inserted into the core slots.

[0101] In this condition, the stator core 1 is locked onto the support ring 16 by actuating the locking supports 47 (figure 14) carried by the locking head 33 projecting upwardly from the support ring 16, so that the stator core 1 is firmly clamped on the support ring 16.

[0102] In a fourth step, the gripper device 22 of the winding gripper unit 21 grips an array H of flat wire conductors from station 23 and brings the array H of conductors to the inserting station 4 (figure 10).

[0103] In a fifth step, a gripper device 22 is lowered above the stator core 1 which is located on the core positioning platform 6 until the docking head 32 at the lower end of column 21 of the gripper device is engaged and locked against the upper locking head 33 projecting from platform 6, by the engagement members 48 (figure 13).

[0104] In a sixth step, the insulation alignment device 64 is controlled to bring the array of alignment pins 65 to its raised position in which the alignment pins 65 are engaged through the slots 2 of the stator core 1 and hold the sheets 3 of insulation paper in a proper condition against the surface of slots 2 (figures 22b, 22c, and 22d).

[0105] In a seventh step, the gripping device 22 of winding gripper unit 21 is moved downwardly to press the array H of conductors H1 into the slots 2 of the stator core 1 , while the alignment pins 65 are simultaneously moved downwardly, so as to leave the space within slots 2 free for receiving the conductors H1. In this manner, the conductors H1 are received within the slots without any damage or improper movement of the insulation sheets 3 (see figures 28, 29, 30, and 31 ).

[0106] Naturally, while the principle of the invention remains the same, the details of construction and the embodiments may widely vary with respect to what has been described by way of example, without departing from the scope of the present invention as defined in the annexed claims.

Claims

CLAIMS1. An apparatus for inserting flat wire conductors (H) into the core (1 ) of a motor stator, comprising:- an insertion station (4) for receiving and positioning a stator core (1 ) having inner slots (2) with insulation sheets (3) received therein,- a winding gripper unit (21 ) with a gripper device (22) for gripping an annular array (H) of flat wire conductors (H1 ) from an area (23) of said apparatus and for inserting said array (H) of flat wire conductors into the slots (2) of a stator core (1 ) positioned at said insertion station (4), said apparatus being characterized in that said insertion station (4) comprises:- a core positioning platform (6) including a flat annular support surface (16A) configured for receiving and supporting the stator core (1 ) in a proper position,- an insulation sheet alignment device (64) arranged below the core positioning platform (6) and comprising pins (65) for alignment of the core insulation sheets (3), said alignment pins (65) being vertically movable between a lowered inoperative position and a raised operative position, in which the alignment pins (65) project upwardly from said core support surface (16A), for engaging the slots (2) of a stator core (1 ) which is positioned on said annular support surface (16A), so that when a stator core (1) is received on said annular support surface (16A), the alignment pins (65) can be moved from its inoperative lowered position to its operative raised position, in which the pins are received within the core slots (2), thereby holding the insulation sheets (3) in their proper positions within the core slots (2), until when the array (H) of flat wire conductors (H1 ) is inserted into the core slots (2).

2. The apparatus according to claim 1 , characterized in that said core positioning platform (6) includes:- a support ring (16) defining said flat annular support surface (16A) which is configured for receiving and supporting the stator core (1 ), said support ring including an annular inner depressed portion with a plurality of slots (16B),- a reference element (20) configured to engage a cooperating cavity(1 C) of the stator core (1 ) for locating the stator core (1 ) in a proper position on the annular support surface (16A), with the slots (2) of the stator core (1 ) being properly aligned with the slots (16B) of said support ring (16).

3. The apparatus according to claim 1 , characterized in that the annular support surface (16A) of said support ring (16) has holes (17) distributed along the circumferential extension of the support ring (16), which are configured for receiving a flow of pressurized air, for enabling obstruction of said holes by the stator core to be checked, as a sign that the lower surface of the stator core (1 ) is correctly in contact with the flat annular support surface (16A) of the support ring (16).

4. The apparatus according to claim 1 , characterized in that said insertion station (4) further includes:- a core locking column (46) having an upper locking head (33) projecting upwardly from said annular support surface (16A), so that the stator core (1 ) which is positioned on said annular support surface (16A) surrounds said upper locking head (33),- wherein said upper locking head (33) is provided with radially movable locking supports (47) which can be moved outwardly to engage and hold an inner surface of a stator core (1) which is positioned on said annular support surface (16A),- wherein said upper locking head (33) is also provided with engagement members (48) configured for engaging a lower docking head (32) of said winding gripper unit (21 ), and- wherein said winding gripper unit (21 ) comprises a guiding column (31 ) for said gripper device (22), the gripper device (22) being vertically movable relative to the guiding column (31 ), and- wherein a lower end of the guiding column (31 ) defines said lower docking head (32) to be engaged by said engagement members (48) of said upper locking head (33), so that said guiding column (31 ) of the winding gripper unit (21 ) can be connected to said core upper locking head (33) of the core locking column (46), whereupon the gripper device (22) of the winding gripper unit (21 ) is configured to be lowered relative to the guiding column (31 ) to insert an array (H) of flat wire conductors (H1 ) gripped by said gripper device (22) into the inner slots (2) of the stator core (1 ) which is positioned on said coresupport surface (16A), while said alignment pins (65) is being lowered and retracted downwardly from the slots (2) of the stator core (1 ).

5. The apparatus according to claim 4, characterized in that said radially movable locking supports (47) for holding the stator core (1 ) and said engagement members (48) for engaging the lower docking head (32) of the winding gripper unit (21 ) are driven by a single common actuator (49) through respective mechanical transmissions.

6. The apparatus according to claim 5, wherein the radially movable locking supports (47) of the upper locking head (33) are driven by said actuator (49) through a transmission including a stem (50) axially movable within said locking column (46) and having a wedge-like upper head (51 ) cooperating with the radially inner ends of said radially movable locking supports (47).

7. The apparatus according to claim 6, wherein said engagement members (48) are pivotally mounted around respective horizontal axes on said upper locking head (33) between an inoperative position and an operative position, said locking members (48) being driven by said actuator (49) through a transmission including a number of auxiliary stems (53) axially movable within said locking column (46), each auxiliary stem (53) being operatively connected to a respective engagement member (48) through a cam-like pin-and-slot mechanism.

8. The apparatus according to claim 7, wherein said auxiliary stems (53) are connected, through a connecting ring (54), to corresponding driving stems (55) whose lower ends (55A) are connected to a plate (56) to which said stem (50) for operating the locking supports (47) is also connected, the vertical movement of said plate (56) being controlled by said actuator (49), which is in the form of a pneumatic cylinder.

9. The apparatus according to claim 8, wherein a spring (57) is mounted around each auxiliary stem (53), and axially interposed between said connecting ring (54) and a fixed support structure.

10. The apparatus according to claim 8, further comprising a sensor (58) for detecting the operating position of said actuating cylinder (49) and a sensor (59) for detecting the operating position of the engagement members (48), the position of the stem (50) which operates the locking supports (47) being controlled through the cooperation of a block (60) withupper and lower limit bolts (62, 63), the position of said block (60) on said stem (50) being adjustable.

11. The apparatus according to claim 1 , wherein the lower ends of said alignment pins (65) of the insulation sheet alignment device (64) are received within outer slots (67) of a star-shaped cylindrical ring (68), the lower end of each pin (65) being clamped inside a respective slot (67) of said star-shaped cylindrical ring (68), between the bottom surface of the slot and an outer ring (69) which is secured to a base plate (70).

12. The apparatus according to claim 11 , wherein said alignment pins (65) are clamped between said star-shaped ring (68) and said outer ring(69) by locking screws (70A) which connect the outer ring (69) to the alignment pins (65), anti-separation screws (71 A) pressing the pins (65) against the bottom of slots (67), and adjustment screws (72A) have their ends in contact with each pin (65).

13. The apparatus according to claim 11 , wherein said base plate(70) is secured to an upper table (71 ) of a slide (72) which is vertically movable on a frame (73) between a lowered inoperative position and a raised operative position in which said alignment pins (65) project upwardly through the slots (16B) of the support ring (16) of the core positioning platform (figure 6), so that in this raised operative position, the alignment pins (65) are engaged within the slots (2) of a stator core (1 ) positioned on the core positioning platform (6), thus holding the insulation sheets (3) in their proper position within the respective slots (2), said upper table (71 ) having a central aperture to avoid interference with the column carrying the upper locking head (33).

14. The apparatus according to claim 4, characterized in that said locking column (46) of the insertion station (4) is arranged through said alignment pins (65).

15. A method for inserting flat wire conductors (H1 ) into the core (1 ) of a motor stator, the method comprising:- positioning a stator annular core (1), having inner slots (2) with insulation sheets (3) received therein, at an insertion station (4),- gripping an annular array (H) of flat wire conductors (H 1 ), by means of a winding gripper unit (21 ) having a gripper device (22), and- inserting said gripped array (H) of flat wire conductors (H1 ) into theslots (2) of the stator core (1 ) positioned at said insertion station (4), said method being characterized in that:- said stator core (1 ) is positioned at said insertion station (4) onto a core positioning platform (6) including a flat annular support surface configured for receiving and supporting the stator core (1 ) in a proper position,- providing an insulation sheet alignment device (64) arranged below the core positioning platform (6) and comprising alignment pins (65) for alignment of the core insulation sheets (3), said alignment pins (65) being vertically movable between a lowered inoperative position and a raised operative position, in which the alignment pins (65) project upwardly from said core support surface (16A) for engaging the slots (2) of the stator core (1 ) which is positioned on said annular support surface (16A), and- moving alignment pins (65) from its inoperative lowered position to its operative raised position after that a stator core (1 ) has been received on said annular support surface (16A), so that said alignment pins (65) are received within the core slots (2), thereby holding the insulation sheets (3) in their proper positions within the core slots (2), until when the array (H) of flat wire conductors (H1 ) is inserted into the core slots (2).

16. The method according to claim 15, characterized in that it includes providing a support ring (16) defining said flat annular support surface (16A) which receives and supports the stator core (1 ), said support ring (16) including an annular inner depressed portion with a plurality of slots (16B), the method also comprising providing a reference element (20) on said core positioning platform (6) which engages a cooperating cavity (1 C) of the stator core (1 ) to locate the stator core (1 ) in a proper position on the annular support surface (16A), with the slots (2) of the stator core (1 ) being properly aligned with the slots (16B) of the support ring (16).

17. The method according to claim 16, characterized in that the annular support surface (16A) of the support ring (16) has holes (17) distributed along the circumferential extension of the support ring (16) which receive a flow of pressurized air for enabling obstruction of said holes (17) by the stator core (1 ) to be checked, as a sign that the lower surface of the stator core (1 ) is correctly in contact with the flat annular support surface (16A) of the support ring (16).

18. The method according to claim 15, characterized in that it includes providing said insertion station (4) with a core locking column (46) having an upper locking head (33) projecting outwardly from said annular support surface (16A), so that the stator core (1 ) which is positioned on the annular support surface (16A) surrounds said upper locking head (33),- wherein said upper locking head (33) is provided with radially movable locking supports (47) which are moved upwardly to engage and hold an inner surface of a stator core (1 ) which is positioned on the annular support surface (16A),- wherein the upper locking head (33) is also provided with engagement members (48) which are configured for engaging a lower docking head (32) of said winding gripper unit (21 ), and- wherein the winding gripper unit (21 ) comprises a guiding column (31 ) for said gripper device (22), the gripper device being vertically movable relative to the guiding column (31 ), and- wherein a lower end of the guiding column (31 ) defines said lower docking head to be engaged by the engagement members (48) of the upper locking head (33), the method comprising connecting said docking head (32) of the winding gripper unit (21 ) to the core upper locking head (33) of the core locking column (46) and subsequently lowering the gripper device (22) of the winding gripper unit (21 ) relative to the guiding column (31 ) to insert an array (H) of flat wire conductors (H1 ) gripped by the gripper device (22) into the inner slots (2) of the stator core (1 ) which is positioned on the annular support surface (16A), while said alignment pins (65) is being lowered and retracted downwardly from the slots (2) of the stator core (1 ).

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