Apparatus for automatically inserting and tightening square conductor motor stator winding

Abstract

An apparatus for inserting and tightening a group of flat wire conductors in the form of hairpins (H) into a comb device (2-2), for forming a nest of hairpins (H) to be transferred into a motor stator, includes a cylindrical comb core (2-2) with axial slots (2-23) for receiving the hairpins. The slots (2-23) also open radially outwardly on apertures (2-24) through which clamp elements (2-12) are radially slidably mounted. A driving mechanism for the clamp elements (2-12) is driven by a first electric motor (3-3) via a first belt transmission (3-4). The comb core (2-2) is rotatable about its axis (3-6), for enabling the insertion of the hairpins (H) with the aid of a cooperating robot (1-1). Rotation of the comb core (2-2) is driven by a second electric motor (3-9) and a second belt transmission (3-11). Once all the hairpins (H) have been positioned, an upper lifting plate (2-6) arranged above the comb core is raised to move the hairpins (H) to a position projecting further upwardly from the comb core (2-2). The vertical movement of the upper lifting plate (2-6) is driven by a third electric motor (4-4) and a third belt transmission (4-5). Before raising the upper lifting plate (2-6), a pressing plate (5-1) is lowered onto the hairpins (H) projecting upwardly from the comb core (2-2) to ensure that all the upper ends of the hairpins are at the same level. The pressing plate (5-1) is vertically movable relative to a support structure (5-2) which is horizontally movable between an operative position and an inoperative position, towards and away from the comb device (2). In one example, the comb device is carried by a rotary platform (3-1), for being easily moved between a first position for the insertion operation and a second position for enabling a completed nest of hairpins to be picked-up for being subsequently transferred into a motor stator. The rotary platform (3-1) can carry two comb devices (2, 2') at diametrically opposite positions.

Description

[0001] “APPARATUS FOR AUTOMATICALLY INSERTING AND TIGHTENING SQUARE CONDUCTOR MOTOR STATOR WINDING”

[0002] TECHNICAL FIELD

[0003] The present invention generally refers to systems and methods for the manufacture of motor stators and relates, in particular, to an apparatus for inserting and tightening flat wire conductors into a comb device, for forming an entire winding to be transferred into a motor stator.

[0004] BACKGROUND

[0005] According to a conventional technique, during the manufacture of a motor stator, the stator windings are obtained by providing flat wires in the form of hairpins which are manually plugged into the slots of the stator core. Due to the large number and variety of the hairpins, when workers repeatedly perform this operation, it is inevitable that they can be distracted and misplace the hairpins, thus causing errors in the positions of the stator windings. As a result, the motor stator cannot be used and needs to be reworked, greatly reducing the production efficiency.

[0006] Various solutions have been proposed for automatically performing the operation of inserting the hairpins into the slots of a motor stator, all of which however have proved to be not completely satisfactory.

[0007] In document EP 3 868 006 B1 , on which the preamble of claim 1 is based, a method for manufacturing a motor stator has been proposed, in which a stator core template is provided. The hairpins are inserted into slots of the template to form a complete nest of hairpins which are subsequently transferred into the slots of a “real” stator core. During insertion of the hairpins into the slots of the template, groups of hairpins are inserted in a first position within the slots and then are radially inwardly moved by pushers towards their final intended position. However, in this solution the above- mentioned pushers engage the portions of the hairpins projecting outwardly from the template, which might result in undesired deformations of the hairpins.

[0008] Therefore, there is still a need of a fully satisfactory solution in this field.

[0009] The present applicant has already proposed a first solution to the above indicated problems in international patent application PCT / CN2024 / 093916, filed on 17 May 2024 and claiming priority of 22 May 2023, which is still secret at the filing date of the present application. The aim of the present invention is to further develop this earlier proposal.

[0010] The object of the present invention is that of solving the above- mentioned problem, by enabling the manufacture of a motor stator to be performed automatically, with a high production efficiency and yet ensuring high precision and quality.

[0011] SUMMARY

[0012] In view of achieving the above-mentioned object, the invention is directed to an apparatus for automatically inserting and tightening a square conductor motor stator winding, for forming an entire winding to be transferred into a motor stator, the apparatus comprising: a comb device including a cylindrical comb core, a comb core axis having a cylindrical lateral surface and two opposite end surfaces and a circumferential array of uniformly distributed axial slots which open at their two opposite ends on the two opposite end surfaces of the comb core, said axial slots being configured for receiving therein a plurality of hairpins, said comb device being characterized in that said axial slots open radially outwardly on apertures of the lateral surface of the comb core, and in that said comb device further comprises: a circumferential array of clamp elements radially slidably mounted within said axial slots of the comb core through said apertures on the lateral surface of the comb core, said clamp elements being configured for clamping the hairpins within said axial slots after all the hairpins have been positioned within said axial slots, a driving mechanism for simultaneously driving a radial movement of all the clamp elements within the respective axial slots of the comb core, and wherein said driving mechanism includes: a circumferential array of radial driving members, surrounding the array of clamp elements, outside the comb core, each driving member being operatively connected to a respective one of said clamp elements, said driving members being radially slidably guided within radial guiding passages of a support annular plate, a driving annular plate, surrounding the comb core and rotatably mounted around a main axis of the comb core on said support annular plate, said driving annular plate having a plurality of spiral slits engaged by camfollowers which are carried by said driving members, said spiral slits being configured so that a rotation of said driving annular plate between two end positions causes a radial movement of said driving members, and hence of said clamp elements, between two end positions, and an actuator for rotating said driving annular plate between said two end positions, and wherein said actuator for rotating said driving annular plate further includes a first electric motor carried by said support annular plate and a first belt transmission driven by said first electric motor and driving a wheel rigidly and coaxially connected to said support annular plate.

[0013] In a preferred embodiment, the apparatus further includes the following features: said support annular plate and said comb core are rigidly supported by a support base which is rotatable about the axis of the comb core, the apparatus for automatically inserting and tightening a square conductor motor stator winding further includes an actuator for driving rotation of said rotatable support base carrying the comb core, for enabling each axial slot of the comb core to be brought to a position for receiving respective hairpins to be inserted with the aid of a cooperating robot, said actuator for driving rotation of said rotatable support base includes a second electric motor carried by a support structure, and a second belt transmission, driven by said second electric motor and driving rotation of a second wheel rigidly and coaxially connected to said rotatable support base.

[0014] According to a further preferred feature, the comb device includes an upper lifting plate whose upper end is arranged above the upper end surface of the comb core and has a circumferential array of radial slots which correspond in number and positions with the axial slots of the comb core, so that when hairpins are being axially plugged into the axial slots of the comb core, the hairpins first engage the radial slots of said upper lifting plate and then the axial slots of the comb core. The upper lifting plate is connected to an actuator which is operable for: - once all the hairpins have been positioned into the comb core, raising said upper lifting plate from a position adjacent the comb core to a raised position, spaced apart upwardly from the comb core, in which the upper lifting plate causes the hairpins to project further upwardly from the upper end surface of the comb core, and

[0015] - subsequently returning the upper lifting plate to its start position adjacent the comb core, after that the clamp elements have been driven to clamp the hairpins within the comb core, so that the hairpins remain in said position projecting upwardly from the comb core in which the entire winding can be picked-up and separated as a whole from the comb core.

[0016] In the preferred embodiment, said upper lifting plate is rigidly connected, through a vertical rod, to a vertically movable plate which is slidably mounted on vertical guiding columns of the support structure. The actuator for driving said upper lifting plate includes a third electric motor carried by the support structure and a third belt transmission, driven by said third electric motor and driving rotation of a vertical screw which is rotatably supported by the support structure, said vertically movable plate rigidly carrying a screw nut engaged on said vertical screw, so that a rotation of said screw driven by said third electric motor causes a vertical movement of said vertically movable plate, together with said vertical rod and said upper lifting plate.

[0017] According to a further preferred feature, a pressing unit is disposed adjacent to the comb device and includes a pressing plate for downwardly pressing hairpins which have been inserted into the axial slots of the comb core, to ensure that all the upper ends of the hairpins are at the same level. The pressing plate is vertically movable relative to a support structure of the pressing unit which is horizontally movable between an operative position and an inoperative position, towards and away from said comb device. The vertical movements of the pressing plate and the horizontal movements of the support structure are driven by corresponding first and second actuators.

[0018] In one example, the support structure of the comb device is carried by a rotary platform at a radially outward position, so that the comb device can be selectively positioned, by rotating the rotary platform, either at a first position, where an insertion operation can be performed with the aid of a robot adjacent to this first position, or at a second position, where a completed winding which has been inserted into the slots of the comb core of the comb device can be picked-up and separated from the comb device to be subsequently inserted into a motor stator. Comb devices in completely opposite positions are disposed in said rotary platform, so that while one comb device is at said first position for the insertion operation, the other comb device is in the second position for enabling a completed winding to be picked-up to be subsequently inserted into a motor stator..

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Further features and advantages of the invention will become readily apparent from the following description of exemplary embodiments, with reference to the accompanying drawings, in which:

[0021] Figures 1 -16 are figures showing an apparatus as already proposed in applicant’s international patent application PCT / CN2024 / 093916, whose description is useful for better understanding the present invention, in which figures 1-16:

[0022] Figure 1 is a structure view i of a comb device and a robot for plugging hairpins into the comb device

[0023] Figure 2 is a partial structural view of the comb device shown in Figure 1 ,

[0024] Figure 3 is a structure view of a support annular plate,

[0025] Figure 4 is a structure view of a comb core axis,

[0026] Figure 5 is a strcutre view of a driving annular plate,

[0027] Figure 6 is a top-down view illustrating part of the structure of the comb device shown in Figure 1 ,

[0028] Figure 7 is a cross-sectional view in a vertical plane of the structure in Figure 6,

[0029] Figure 8 is a structure view of a comb core axis of the comb device,

[0030] Figure 9 is a detail at an enlarged scale of a single clamp element with the associated driving member,

[0031] Figure 10 is a perspective view of a support annular plate shown in Figure 3,

[0032] Figure 11 is a partial structure view of the comb device,

[0033] Figure 12 is a partial view of the comb device at an enlarged scale, Figure 13 is a structure view of the upper portion of the comb device, Figures 13A-13D show different stages of the process for inserting the hairpins,

[0034] Figures 14-16 are structure views of three different stages of the actual operation of the comb device,

[0035] Figure 17 is a structure view of the apparatus according to the invention,

[0036] Figure 18 is a structure view of a comb device forming part of the apparatus in Figure 17,

[0037] Figure 19 shows a cross-sectional view of the structure shown in Figure 18,

[0038] Figure 20 is a structural view of a portion of the comb device in figures 18 and 19,

[0039] Figure 21 is a cross-sectional view of the portion of the comb device shown in figure 20,

[0040] Figure 22 shows a detail of figure 21 at an enlarged scale,

[0041] Figure 23 shows a structural view of a portion of the comb device in figures 18 and 19,

[0042] Figure 24 is a cross-section view of the structure in figure 23,

[0043] Figures 25 is a structural view of another portion of the comb device,

[0044] Figure 26 is a structural view of the structure shown in Figure 25 from another direction,

[0045] Figure 27 is a structural view of a pressing unit in one operating position,

[0046] Figure 28 is a structural view of the pressing unit in another operating position,

[0047] Figure 29 is a structural view, at an enlarged scale, of a detail of the pressing unit,

[0048] Figure 30 is a structural view of the driving transmission for rotating the rotary platform visible in figure 17,

[0049] Figures 31 is a structural view of a robot cooperating with the apparatus of the invention, and

[0050] Figure 32 is a structural view of the structure shown in Figure 31 from another direction.

[0051] Reference list 1 -1 robot

[0052] 1-2 gripper

[0053] 1-11 first gripper

[0054] 1-12 second gripper

[0055] 1-13 slider

[0056] 1-14 motorized crank

[0057] 2 comb device

[0058] 2-0 stationary frame

[0059] 2-1 stationary plate

[0060] 2-2 comb core

[0061] 2-21 lateral surface

[0062] 2-22 end surface

[0063] 2-23 axial slot

[0064] 2-24 opening

[0065] 2-25 passage

[0066] 2-3 support

[0067] 2-4 support annular plate 2-41 radial guiding passage 2-42 upper peripheral edge 2-43 portion 2-44 protrusion

[0068] 2-5 actuator

[0069] 2-51 crank

[0070] 2-6 upper lifting plate 2-61 radial slot

[0071] 2-7 roller

[0072] 2-8 driving annular plate 2-81 spiral slit

[0073] 2-82 slot

[0074] 2-83 radial extension

[0075] 2-9 radial driving member 2-10 cam follower

[0076] 2-11 vertical axis

[0077] 2-12 clamp element 2-13 cylinder 2-131 plate

[0078] 2-14 stem

[0079] 2-15 guiding rod

[0080] 2-16 connecting rod

[0081] 2-17 covering plate

[0082] 3-1 rotary platform

[0083] 3-2 vertical axis

[0084] 3-3 first electric motor

[0085] 3-31 reducer gear unit

[0086] 3-4 first belt transmission 3-41 toothed belt 3-42 first gear 3-43 first wheel 3-5 support base 3-6 axis

[0087] 3-7 rotary plate

[0088] 3-8 support structure

[0089] 3-9 second electric motor 3-10 reduction gear device 3-11 second belt transmission 3-12 belt

[0090] 3-13 drive wheel

[0091] 3-14 second wheel

[0092] 3-15 electric slip ring

[0093] 4-1 vertical rod

[0094] 4-2 vertically movable plate

[0095] 4-3 vertical guiding column

[0096] 4-4 third electric motor

[0097] 4-5 third belt transmission 4-6 drive belt 4-7 drive wheel 4-8 driven wheel 4-9 vertical screw 4-10 screw nut 4-11 pneumatic lock 4-12 column

[0098] 5 pressing unit

[0099] 5-1 pressing plate

[0100] 5-2 support structure

[0101] 5-21 vertical upright

[0102] 5-22 horizontal cantilever

[0103] 5-4 first actuator

[0104] 5-41 fourth electric motor

[0105] 5-5 second actuator

[0106] 5-51 horizontal rail

[0107] 5-6 platform

[0108] 5-7 base plate

[0109] 6 fifth electric motor

[0110] 6-1 reducer

[0111] 6-2 gear box

[0112] 6-3 rotating annular plate

[0113] 6-4 stationary column

[0114] DETAILED DESCRIPTION

[0115] As indicated, figures 1-16 show an apparatus as already proposed in applicant’s international patent application PCT / CN2024 / 093916 (which is still secret at the filing date of the present application), whose description is however useful for better understanding the present invention.

[0116] In Figure 1 , reference numeral 2 generally designates an example of a comb device according to the present invention. The comb device 2 includes a cylindrical comb core 2-2, better shown in Figure 8, having axial slots 2-23 for receiving a group of hairpins (the structure indicated by the letter H in the figure).

[0117] Figure 1 shows one hairpin carried by a gripper 1-2 of a robot 1 -1 , which is used for automatically plugging the hairpins into the axial slots 2- 23 (figure 2) of the comb core 2-2 of the comb device 2. The comb device of the invention is used to enable a complete group of hairpins to be automatically plugged into the axial slots 2-23 of a comb core 2-2, after which the complete winding can be transferred from the comb core 2-2 into the slots of a motor stator. As shown in detail in Figure 8, the cylindrical comb core 2-2 has a cylindrical lateral surface 2-21 , and two opposite end surfaces 2-22. The comb core 2-2 has a circumferential array of uniformly distributed axial slots 2-23 which extend axially from one end surface 2-22 to the other, so that the axial slots 2-23 open at the two opposite ends of the comb core 2-2.

[0118] The slots 2-23 also open radially outwardly, on apertures 2-24 of the outer surface 2-21 of the comb core.

[0119] Reverting to Figure 1 , each hairpin has a general U-shape configuration, with two legs and an upper bridge portion. The hairpins are plugged into the slots 2-23 of the comb core 2-2 with their legs oriented downwardly.

[0120] In a preferred embodiment, the hairpins are of a type defined by a wire having a flat, non-circular cross-section.

[0121] Referring to Figure 2, the example of the comb device illustrated therein includes a stationary frame 2-0 carrying a stationary plate 2-1 on which the comb core 2-2 is locked in position (see also Figure 7) by any known means. This stationary plate 2-1 carries, by means of a number of supports 2-3, an annular stationary plate 2-4, better shown in Figures 3 and 10, which surrounds the comb core 2-2.

[0122] The comb device 2 of the invention further includes a circumferential array of clamp elements 2-12 radially slidably mounted within the axial slots 2-23 of the comb core 2-2, through the apertures 2-24 of the lateral surface 2-21 of the comb core 2-2. In the illustrated example, the comb core 2-2 has 48 axial slots 2-23, so that 48 clamp elements 2-12 are provided, each clamp element 2-12 being slidable radially within a respective slot 2-23 through to the openings 2-24.

[0123] Figure 9 of the drawings shows, at an enlarged scale, the detail of a single clamp element 2-12. Each axial slot 2-23 of the comb core 2-2 (Figure 8) is formed with a rectangular cross-section, defined by two parallel side surfaces. Correspondingly, each clamp element 2-12 is in form of a vertical plate, slidably mounted between the two-side surfaces of each axial slot 2- 23, the vertical dimension of each clamp element 2-12 being lower than the vertical dimension of the openings 2-24 of the axial slots 2-23 on the lateral surface 2-21 of the comb core 2-2.

[0124] As shown in greater detail in Figures 4 and 9, each clamp element 2- 12 is driven by a driving member 2-9 in the form of a rod member with an inverted T-shaped cross-section.

[0125] Each radial driving member 2-9 has one end hinged to the respective clamp element 2-12 at 2-11 , around a vertical axis, and has the opposite end carrying a cam-follower 2-10 in form of a freely rotatable roller, whose function will become clear in the following.

[0126] The radial driving members 2-9, associated with the clamp elements 2-12, are radially guided within the radial guiding passages 2-41 of the support annular plate 2-4 (see Figures 3, 10).

[0127] In the illustrated example, the support annular plate 2-4 has a projecting peripheral edge for rotatably supporting an annular driving plate 2-8 (see Figure 5) above the support annular plate 2-4.

[0128] As shown in Figures 11 , 12, the driving annular plate 2-8 has a plurality of spiral slits 2-81 engaged by respective cam-followers 2-10 carried by respective radial driving members 2-9.

[0129] In the illustrated example, each spiral slit 2-81 is engaged by two cam-followers 2-10 carried by two adjacent radial driving members 2-9 which are operatively connected to two respective clamp elements 2-12.

[0130] The spiral slits 2-81 are configured in such a way that a rotation of the driving annular plate 2-8 between two end positions causes a radial movement of each clamp element 2-12 between two end positions. Most preferably, the spiral-slit 2-81 are so configured that a rotation of the driving annular plate 2-8 at a constant speed causes a radial movement of the clamp elements 2-12 at a constant speed.

[0131] As indicated, each spiral-slit 2-81 is engaged by two cam-followers 2-10. Therefore, the number of spiral slits 2-81 is half the number of the clamp elements 2-12. Therefore, for a comb core having 48 slots, 48 clamp elements 2-12 are provided, while only 24 spiral slits 2-81 are provided in the driving annular plate 2-8. Due to the above indicated arrangement, the two radial driving members 2-9 carrying the cam-followers 2-10, which are engaged within a same spiral-slit 2-81 , have a different length.

[0132] As it will be understood, the above indicated preferred configuration enables the driving annular plate 2-8 to be made with a simpler configuration.

[0133] In the illustrated example, rotation of the annular driving plate 2-8 is controlled by a motor 2-5 carried by the stationary base plate 2-1 . Motor 2- 5 controls the rotation of a crank 2-51 , carrying a roller 2-7 engaged within a slot 2-82 of a radial extension 2-83 of the driving annular plate 2-8.

[0134] In the illustrated example, the comb device 2 of the invention further includes an upper lifting plate 2-6, arranged above the upper end surface of the comb core 2-2 and having a circumferential array of radial slots 2-61 (Figure 13) corresponding in number and positions with the axial slots 2-23 of the comb core 2-2, so that when the hairpins H are axially plugged into the slots 2-23 of the comb core 2-2, they first engage from above the radial slots 2-61 of the upper lifting plate 2-6 and then the axial slots 2-23 of the comb core 2-2.

[0135] The upper lifting plate 2-6 is operatively connected to the stem 2-14 of a cylinder 2-13. With reference to Figures 6-7, the cylinder 2-13 is arranged vertically below the stationary plate 2-1 , along the axis of the comb core 2-2. The body of cylinder 2-13 is carried by a plate 2-131 which is supported by connecting rods 2-16 secured to the lower end surface of comb core 2-2. The cylinder 2-13 has a stem 2-14, having an upper end connected to the central portion of the lifting upper plate 2-6. In addition, the upper plate 2-6 is connected to guiding rods 2-15 (Figure 6) which are slidably guided through passages 2-25 (Figure 8) of the comb core 2-2.

[0136] With reference to Figure 1 , a dustproof covering plate 2-17 is secured on the upper peripheral edge 2-42 of the support annular plate 2-4. The peripheral edge 2-42 is interrupted at a portion 2-43 (Figure 3) so as to leave space for the radial extension 2-83 of the driving annular plate 2-8.

[0137] In operation, during the stage in which the hairpins are plugged through radial slots 2-61 of the upper lifting plate 2-6 and through the axial slots 2-23 of the comb core 2-2, the upper lifting plate 2-6 is in the lower position shown in Figure 14, adjacent to the upper end surface of the comb core 2-2.

[0138] Figures 13A-13D show different stages of the hairpin insertion process. Figure 13A shows an initial stage in which a first set of hairpins has been inserted into axial slots 2-2, with the clamp elements 2-12 being arranged in a radially innermost position. After the insertion of this first set of hairpins, the clamp elements 2-12 are slightly moved radially outwardly to leave a radial space within each axial slot slightly greater that the radial dimensions of two wires (see figures 13B, 13C) so that a second wire H2 can be introduced radially outside a first wire H1 which has been previously inserted. The clamp elements are then progressively moved radially outwardly, to enable a total of six wires (in this example H1 , H2, and H3). H4, H5, and H6 to be received within each slot (see figure 13D).

[0139] After the insertion of all the hairpins, the all hairpins are first pressed downwardly by a pressing plate (not shown in the drawings) to ensure that all the upper ends of the hairpins are at the same level. At this stage, the upper lifting plate 2-6 is brought from the lowered position of figure 14 to a raised position as shown in Figure 15, with the aid of cylinder 2-13. In this manner, the upper lifting plate 2-6 causes all the hairpins to move axially upwardly relative to the comb core 2-2, so as to reach a position in which they project further upwardly from the comb core. After this step, the driving annular plate 2-8 is rotated by actuating the motor 2-5, so as to move the clamp elements 2-12 radially inwardly to gently press the hairpins against the radially inner end surfaces of axial slots 2-23. With the hairpins clamped in this manner, the upper lifting plate 2-6 is then brought back to its lowered position adjacent to the upper end surface of the comb core 2-2, as shown in Figure 16, while the hairpins are compelled to remain in the same position relative to the comb core 2-2. In this manner, the group of hairpins H is arranged in a position projecting upwardly from the comb core, where it can be easily picked-up for being transferred to a subsequent station where the group of hairpins is inserted into the slots of a motor stator.

[0140] Referring now to figures 17-27, these figures show an exemplary embodiment of an apparatus for automatically inserting and tightening a square conductor motor stator winding according to the present invention. The apparatus comprises a comb device 2 having a general construction and operation like that of the comb device 2 shown in figures 1 -16, except for a number of specific improvements which will be described in detail in the following.

[0141] In the example of figure 17, a comb device 2 is carried by a rotary platform 3-1 , which is rotatable around a vertical axis 3-2. The comb device 2 is arranged on the rotary platform 3-1 at a radially outward position with respect to axis 3-2, so that the comb device 2 can be selectively positioned, by rotating the rotary platform 3-1 , either at a first position (the left position in figure 17), where an insertion operation can be performed with the aid of a robot adjacent to this first position, or at a second position (the right position in figure 17), where a completed winding has been inserted into the slots 2-23 of the comb core 2-2 of the comb device 2 can be picked-up and separated from the comb device 2 to be subsequently inserted into a motor stator.

[0142] In a further embodiment, a second identical comb device (the position of the mark 2' in the figure) can be provided on the rotary platform 3-1 (in place of the diagrammatic cylindrical volume shown in figure 17) at a position which is diametrically opposite to the first comb device 2, so that while one comb device is at the first position for the insertion operation, the other comb device is in the second position for enabling a completed nest of hairpins to be picked-up to be subsequently inserted into a motor stator.

[0143] It is to be noted however, that the arrangement of a rotary platform 3-1 carrying one or more comb devices is presented herein just as an exemplary embodiment. According to the invention, it would be possible to provide a single comb device which is transferred from an insertion station to a pick-up station in any other known way. Alternatively, it would be also possible that after the insertion operation, the comb device remains at its position and that the pick-up operation of the completed winding is carried out in that same position.

[0144] A first difference of the apparatus of figures 17-27 with respect to that of figures 1 -16 relates to the means for actuating the driving mechanism of the clamp elements 2-12. The driving mechanism per se is identical to that of figure 2, in that it includes the driving annular plate 2-8 (see in particular figure 22) rotatable within the support annular plate 2-4. The driving annular plate 2-8 has the above-described spiral slits 2-81 engaged by the camfollowers 2-10, which are carried by the driving members 2-9 connected to the clamp elements 2-12, as also already described.

[0145] In the case of the present invention, however, rotation of the driving annular plate 2-8 is controlled by a first electric motor 3-3 via a first belt transmission 3-4 (see figures 18, 19, 20, and 21 ). The first electric motor 3- 3 is carried by a projecting portion 2-44 of the support annular plate 2-4. The first belt transmission 3-4 includes a toothed belt 3-41 engaged on a first (relatively small) gear 3-42 and on a (relatively large) first wheel 3-43. The first wheel 3-42 is rotatably supported by portion 2-44 of the support annular plate 2-4 and is driven by the first electric motor 3-3 with the interposition of a reducer gear unit 3-31. The first wheel 3-43 is rigidly and coaxially connected to the support annular plate 2-4.

[0146] Due to this arrangement, during the insertion operation, the positions of the clamp elements 2-12 can be efficiently and more precisely controlled via the first electric motor 3-3 and the first belt transmission 3-4.

[0147] Another difference of the apparatus of the invention with respect to the apparatus of figures 1 -16 lies in that the annular support plate 2-4 and the comb core 2-2 are rigidly supported by a support base 3-5 which is rotatable about the axis 3-6 of the comb core 2-2 (see for example figure 19). With reference in particular to figures 23 and 24, the support base 3-5 is rigidly connected to a rotary plate 3-7 which is rotatably mounted on the support structure 3-8 of the apparatus (which is rigidly connected to the rotary platform 3-1 in the embodiment of figure 17).

[0148] The apparatus of the present invention further comprises an actuator for driving rotation of the rotary plate 3-7, for enabling each axial slot 2-23 of the comb core 2-2 to be brought to a position for receiving respective hairpins to be inserted with the aid of the cooperating robot 1 -1. This actuator comprises a second electric motor 3-9 carried by the support structure 3-8 along with an associated reducer gear device 3-10. The second electric motor 3-9 drives rotation of the rotary plate 3-7 via a second belt transmission 3-11 , including a belt 3-12 engaged on a drive wheel 3-13 driven by the first electric motor 3-9 via reducer gear device 3-10 and a second wheel 3-14 rigidly and coaxially connected to rotary plate 3-7 (see figure 24). As shown in figure 24, an electric slip ring 3-15 is coaxially connected to drive the wheel 3-12 for enabling electric supply to the second electric motor 3-3.

[0149] Another difference of the apparatus of the invention with respect to the apparatus of figures 1 -16 relates to the actuator for the upper lifting plate

[0150] 2-6. Referring to figures 19 and 25, 26, the upper lifting plate 2-6 is rigidly connected, through a vertical rod 4-1 , to a vertically movable plate 4-2 which is slidably mounted on vertical guiding columns 4-3 of the support structure

[0151] 3-8 of the apparatus. Vertical rod 4-1 is connected to the vertically movable plate 4-2 through a transition element including a pair of aligning bearings, the bearing housing being connected to the plate 4-2. The actuator for driving the upper lifting plate 2-6 includes a third electric motor 4-4 carried by the support structure 3-8 of the apparatus and a third belt transmission

[0152] 4-5 (figure 19), including a drive belt 4-6 engaged on a drive wheel 4-7 driven by the third electric motor 4-4 and a driven wheel 4-8 rigidly connected to a vertical screw 4-9 which is rotatably supported by the support structure 3-8 of the apparatus. The vertically movable plate 4-2 rigidly carries a screw nut 4-10 (preferably a ball screw nut) engaged on said vertical screw 4-9 (see figure 25), so that a rotation of said screw 4-9 driven by the third electric motor 4-4 causes a vertical movement of the vertically movable plate 4-2, together with the vertical rod 4-1 and the upper lifting plate 2-6.

[0153] Figure 25 shows a pneumatic lock 4-11 cooperating with a column 4- 12 to lock the vertically movable plate 4-2 in position.

[0154] In the preferred embodiment, the apparatus of the invention further comprises a pressing unit 5 (see figure 17 and figures 27-29) including a pressing plate 5-1 for pressing hairpins which have been inserted into the axial slots 2-23 of the comb core 2-2 downwardly, to ensure that all the upper ends of the hairpins are at the same level. The pressing plate 5-1 is vertically movable relative to a support structure 5-2 of the pressing unit 5 which is horizontally movable between an operative position and an inoperative position, towards and away from the comb device 2. The vertical movements of the pressing plate 5-1 and the horizontal movements of the support structure 5-2 are driven by corresponding first and second actuators

[0155] 5-4 and 5-5. In this example, the horizontally movable support structure 5-2 has an L-shaped configuration with a vertical upright 5-21 and a cantilever horizontal arm 5-22. The terminal end of the cantilever arm 5-22 supports the vertically movable pressing plate 5-1 which can be driven by a screw- and-nut actuator 5-4 driven by a fourth electric motor 5-41 . The upright 5- 21 of the support structure 5-2 has a base slidably mounted on horizontal rails 5-51 (figure 29) carried by a platform 5-6 on which an actuator (actuating cylinder) 5-5 is mounted, for actuating the horizontal movements of the support structure 5-2.

[0156] The platform 5-6 is carried by four posts 5-7 which are connected to a base plate 5-7 (see figure 17). With reference to figures 17 and 30, the base plate 5-7, which supports the pressing unit 5, is spaced upwardly with respect to the rotary platform 3-1 and does not take part in the rotation of the platform 3-1 . In figure 30, a fifth electric motor 6 is shown which drives rotation of the rotary platform 3-1 of figure 17 through a reducer 6-1 and a gear box 6-2 which transmits the rotation to a rotating annular plate 6-3. Inside the rotating annular plate 6-3, a stationary column 6-4 is arranged, to which the base plate 5-7 of the pressing unit is rigidly connected.

[0157] At the end of an insertion operation by which all the hairpins have been introduced into the axial slots 2-23 of the comb core 2-2, with the aid of robot 1-1 , at the left position in figure 17, the horizontally movable support structure 2-2 of the pressing unit 5 is moved from the inoperative position of figure 27 to the operative position of figure 28, after which the pressing plate 5-1 is lowered onto the hairpins.

[0158] After this operation, the pressing unit 5 is retracted and the upper lifting plate 2-6 is actuated, according to the same cycle of operations which have been described with reference to figures 1 -16, so that the completed entire winding is left in the arrangement projecting upwardly from the comb device 2-2. In this condition, with reference to figure 17, the rotary platform 3-1 can be rotated by 180°, so as to bring the comb device 2-2 with the completed entire winding to the position on the right in figure 17, so that the nest of hairpins H can be picked-up by any suitable means (not shown) for transfer to a station where the entire winding is inserted into a motor stator.

[0159] Figures 31 and 31 show an example of robot 1 -1 for inserting the hairpins into the axial slots 2-23. In this example, robot 1 -1 includes two grippers, that is, a first gripper 1 -11 and a second gripper 1 -12 for handling each hairpin. First gripper 1 -11 is carried by a slide 1 -13, while second gripper 1 -12 is carried by a motorized crank 1 -14. However, any suitable robot of any known type can be used in the apparatus of the invention.

[0160] Naturally, where the principle of the invention remains the same, the details of construction and the embodiment may widely vary with respect to what has been described and illustrated purely by way of example, without departing from the scope of the present invention, as defined in the appended claims.

Claims

CLAIMS1. An apparatus for automatically inserting and tightening a square conductor motor stator winding, used for inserting and tightening a group of flat wire conductors in the form of hairpins into a comb device and for forming an entire winding for transfer to an electric stator, the apparatus for automatically inserting and tightening a square conductor motor stator winding comprising: a comb device (2) including a cylindrical comb core (2-2), a comb core axis having a cylindrical lateral surface (2-21 ), two opposite end surfaces (2-22) and a circumferential array of uniformly distributed axial slots (2-23) which open at their two opposite ends on the two opposite end surfaces (2-22) of the comb core (2-2), said axial slots (2-23) being configured for receiving therein a plurality of hairpins, said apparatus being characterized in that said axial slots (2-23) of the comb core (2-2) also open radially outwardly on apertures (2-24) of the lateral surface (2-21 ) of the comb core (2-2), and in that said comb device (2) further comprises: a circumferential array of clamp elements (2-12) radially slidably mounted within said axial slots (2-23) of the comb core (2-2) through said apertures (2-24) on the lateral surface (2-21 ) of the comb core (2-2), said clamp elements (2-12) being configured for clamping the hairpins within said axial slots (2-23) after that all the hairpins have been positioned within said axial slots (2-23), a driving mechanism for simultaneously driving a radial movement of all the clamp elements (2-12) within the respective axial slots (2-23) of the comb core (2-2), and wherein said driving mechanism includes: a circumferential array of radial driving members (2-9), surrounding the array of clamp elements (2-12) outside the comb core (2-2), each driving member (2-9) being operatively connected to a respective one of said clamp elements (2-12), said driving members (2-9) being radially slidably guided within radial guiding passages (2-41 ) of a support annular plate (2-4), a driving annular plate (2-8), surrounding the comb core (2-2) and rotatably mounted around a main axis of the comb core (2-2) on said supportannular plate (2-4), said driving annular plate (2-8) having a plurality of spiral slits (2-81 ) engaged by cam-followers (2-10) which are carried by said driving members (2-9), said spiral slits (2-81 ) being configured so that a rotation of said driving annular plate (2-8) between two end positions causes a radial movement of said driving members (2-9), and hence of said clamp elements (2-1 ) between two end positions, and an actuator (2-5) for rotating said driving annular plate (2-8) between said two end positions, and further wherein: said actuator (2-5) for rotating said driving annular plate (2-8) comprises a first electric motor (3-3) carried by said support annular plate (2-4) and a first belt transmission (3-4) driven by said first electric motor (3- 3) and driving a wheel (3-43) rigidly and coaxially connected to said support annular plate (2-4).

2. The apparatus for automatically inserting and tightening a square conductor motor stator winding according to claim 1 , wherein: said support annular plate (2-4) and said comb core (2-2) are rigidly supported by a support base (3-5) which is rotatable about the axis (3-6) of the comb core (2-2), the apparatus for automatically inserting and tightening a square conductor motor stator winding further comprises an actuator for driving rotation of said rotatable support base (3-5) carrying the comb core (2-2), for enabling each axial slot (2-23) of the comb core (2-2) to be brought to a position for receiving respective hairpins to be inserted with the aid of a cooperating robot (1 -1 ), said actuator for driving rotation of said rotatable support base (3-5) comprises a second electric motor (3-9) carried by a support structure (3- 8), and a second belt transmission (3-11 ), driven by said second electric motor (3-9) and driving rotation of a second wheel (3-14) rigidly and coaxially connected to said rotatable support base (3-5).

3. The apparatus for automatically inserting and tightening a square conductor motor stator winding according to claim 1 , wherein the comb device (2) further includes an upper lifting plate (2-6) whose upper end is arranged above the upper end surface of the comb core (2-2) and has acircumferential array of radial slots (2-61 ) which correspond in number and positions with the slots (2-23) of the comb core (2-2), so that when hairpins are being axially plugged into the axial slots (2-23) of the comb core (2-2), the hairpins first engage the radial slots (2-61 ) of said upper lifting plate (2- 6) and then the axial slots (2-23) of the comb core (2-2), said upper lifting plate (2-6) being connected to an actuator (2-5) which is operable for:- once all the hairpins have been positioned into the comb core (2-2), raising said upper lifting plate (2-6) from a position adjacent the comb core (2-2) to a raised position, spaced apart upwardly from the comb core (2-2), in which the upper lifting plate (2-6) causes the hairpins to project further upwardly from the upper end surface (2-22) of the comb core (2-2), and- subsequently returning the upper lifting plate (2-6) to its start position adjacent the comb core (2-2), after that the clamp elements (2-12) have been driven to clamp the hairpins within the comb core (2-2), so that the hairpins remain in said position projecting upwardly from the comb core (2-2) in which the entire winding can be picked-up and separated as a whole from the comb core (2-2), and wherein said upper lifting plate (2-6) is rigidly connected, through a vertical rod (4-1 ), to a vertically movable plate (4-2) which is slidably mounted on vertical guiding columns (4-3) of the support structure (3-8) of the apparatus, and wherein a mechanism for driving said upper lifting plate (2-6) includes a third electric motor (4-4) carried by the support structure (3-8) and a third belt transmission (4-5), driven by said third electric motor (4-4) and driving rotation of a vertical screw (4-9) which is rotatably supported by the support structure (3-8), said vertically movable plate (4-2) rigidly carrying a screw nut (4-10) engaged on said vertical screw (4-9), so that a rotation of said screw (4-9) driven by said third electric motor (4-4) causes a vertical movement of said vertically movable plate (4-2), together with said vertical rod (4-1 ) and said upper lifting plate (2-6).

4. The apparatus for automatically inserting and tightening a square conductor motor stator winding according to claim 1 , wherein, adjacent to said comb device (2), a pressing unit (5) is arranged, which includes a pressing plate (5-1 ) for downwardly pressing hairpins which have beeninserted into the axial slots (2-23) of the comb core (2-2), to ensure that all the upper ends of the hairpins are at the same level.

5. The apparatus for automatically inserting and tightening a square conductor motor stator winding according to claim 1 , wherein said pressing plate (5-1 ) is vertically movable relative to a support structure (5-2) of the pressing unit (5) which is horizontally movable between an operative position and an inoperative position, towards and away from said comb device (2), and wherein the vertical movements of the pressing plate (5-1 ) and the horizontal movements of said support structure (5-2) are driven by corresponding first and second actuators (5-4, 5-5).

6. The apparatus for automatically inserting and tightening a square conductor motor stator winding according to any of claims 1 -5, wherein the support structure (3-8) of the comb device (2) is carried by a rotary platform (3-1 ) at a radially outward position, so that the comb device (2) can be selectively positioned, by rotating the rotary platform (3-1 ), either at a first position, where an insertion operation can be performed with the aid of a robot (1 -1 ) adjacent to this first position, or at a second position, where a completed winding which have been inserted into the axial slots (2-23) of the comb core (2-2) of the comb device (2) can be picked-up and separated from the comb device (2) to be subsequently inserted into a motor stator.

7. The apparatus for automatically inserting and tightening a square conductor motor stator winding according to claim 6, including two comb devices (2) in completely opposite positions in said rotary platform (3-1 ), so that while one comb device (2) is at said first position for the insertion operation, the other comb device (2) is in the second position for enabling a completed winding to be picked-up to be subsequently inserted into a motor stator.

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