PRODUCTION LINE FOR PALLET MOUNTED ELECTRIC MOTOR STATORS

Abstract: In a production line for electric motor stators, the stators are rigidly fixed individually, onto respective individual pallets which advance along conveyor belts, in proximity to which the necessary stator-working stations are located; mechanical means are also provided for removing the pallets from the belts and handling them so that the respective stators become disposed in positions corresponding with the working stations located along the line, and in proximity to which said mechanical means are provided.

Description: The invention relates to a production line for pallet-mounted electric motor stators. At the present time, stators lie directly on conveyor belts which move along lines. The various working stations are provided at the sides of these lines. These stations include the stations for slot insulation, mounting the shoulders and mounting the terminals on them, winding formation, wire end termination, terminal soldering, coil baking, and stator electrical testing. On reaching one of these stations, the stators must be removed from the conveyor belt and positioned in the working station, after which the stator is again returned to the line for feeding to the next station. This type of production cycle considerably penalizes productivity, as the stators have to be continuously transferred to and from the various working stations by respective members which remove them from the belts, transport them to the station, return them to the belts and position them thereon. The members, which are complicated, also penalize the line from an economic viewpoint. Document DE-2208865 discloses a device for holding a stator at a coil insertion machine. This device is also capable of rotating the stator in order to present it on a conveyor or present it to another work station with a required orientation. This device, however, does not disclose rotating the stator with the conveying means i.e. the pallet in order to position the stator with the corresponding work station. Document FR-A-2370659 discloses a conveyor apparatus comprising stators clamped to carriages for conveyance between stations of a production line. The stators and the carriages can be removed from the conveying line in order to transfer them to work station. This reference, however, does not include rotating the pallet so as to position the stators with the corresponding work stations. Document GB-A-2145355 relates to an apparatus and method for the automatic production of armatures for small electric motors. The armatures are clamped in work piece holders and are moved to successive stations of the apparatus by a conveyor belt. The work piece holders are raised in relation to the conveyor belt by positioning a locking bolt and are held in the working position. However, there is no disclosure in this reference of appendices extending from the hollow body of a pallet to temporarily receive the ends of wire windings formd on the stator, nor is there any disclosure of rotating the stator support pallets laterally of the production line in order to position the stators with their axes substantially horizontal and perpendicular to the axis of the line. To obviate these drawbacks, the invention provides a line in which the stators are rigidly fixed to pallets which slide on the conveyor belt and in certain stations, such as the winding formation and termination stations, the pallet is raised together with the stator and rotated through 90 degrees so that it faces the machine which is to carry out the necessary work. By this means, the idle times involved in transferring the stator to and from the various working stations can be considerably reduced. In certain stations these transfers are not required as the required work is carried out directly on the stator without removing it from the belts. In other stations each transfer is simply a matter of rotating the pallet on which the stator is fixed. In addition to increasing productivity, equipment costs and the complexity of the entire line are also reduced. The above and further objects which will be more apparent hereinafter are attained according to the invention by a production line for electric motor stators, as claimed in claim 1. Embodiments of the invention are described hereinafter by way of non-limiting examples with reference to the accompanying drawings in which: Fig. 1 is a section through a pallet, on which a stator is mounted with a vertical axis, which is advancing along a transfer line in proximity to a working station in which the pallet, as a first example of handling it, is turned over sideways; Fig. 2 is a plan view of the position shown in fig. 1; Fig. 3 is a side view of the position shown in Figures 1 and 2, with the pallet being shown in its turned position by dashed lines, and with a working station, namely the winding formation station, being shown diagrammatically; Figure 4 is a view of a line portion comprising two winding formation stations and one termination station. Figures 1 and 2 show a stator 10, of conventional type, mounted with its axis vertical on a hollow cylindrical body 11 fixed lowerly to a base 12. Base 12 and body 11 form a pallet which slides on the belts 13 of the transfer line. The stator 10 can for example be fixed by screws 14 to shoulders 15 on the body 11, which also comprises appendixes 16 used for temporarly anchoring the ends of the wires 17 after forming the windings 18 on the stator slots. In certain working stations in which it would be very complicated to arrange the machine above the line, such as for example the winding formation station 20 (Figures 3 and 4), a device is provided for turning the pallet through 90 degree, this consisting of an arm 22 provided at one end with a tube 23 keyed onto the rod 24 of a rotating pneumatic cylinder. At its other end the arm 22 is provided with jaws 27 hinged at 26, for gripping the pallet body 11. On operating the cylinder 25 and a further cylinder, suitable linkages (not shown) cause the jaws 27 to close onto the body 11, and then the arm 22 to rotate through 90 degree until the position shown by dashed lines in Fig. 3 is reached. In this position, the stator 10 has its axis horizontal, and the windings can be formed on it by means of the apparatus 20. Figure 3 shows an apparatus in which the needle 30 is eccentric and enables the windings to be made without the aid of the conventional forming shoes. This form of eccentric needle 30 is the subjected matter of Italian patent No.1200443 of April 2, 1985 in the name of the present Applicant. By the Italian patent No. 1185206 of July 9, 1985, the Applicant has also patented a second method which enables the windings to be formed without the use of forming shoes, and which could be advantageously employed on the line according to the invention in that the use of forming shoes and thus of conventional apparatus for forming the windings on the stator could make it difficult to work on stators fixed to pallets, however by suitably changing the form of the pallet, the use of apparatus 20 of a type different from that shown in Fig. 3 or different from those advantageously proposed by the Applicant could be used, without leaving the scope of the invention, which does in no way aim to propose a method for forming the windings. Figure 4 shows two pairs of winding station 20 with the aim of applying to an eccentric needle 30, the subject matter of Italien Patent No. 1200443 of April 2, 1985 in the name of the present Applicant, in which each needle 30 winds on one pole of a stator, so that if two stations with suitably orientated needles 30 are placed side by side, the windings are made in the first station on one pole and then in the second station on the other pole. If however apparatus 20 are used in which the needles 30 simultaneously form the windings on both poles of each stator, the station 20 can be a single station while advantageously retaining the pair of needles 30 for operating simultaneously on two stators, thus increasing the line productivity. In known manner, when the windings are finished, the ends of the wires 17 are temporarily anchored on side supports of the stator 10, which in this case are the pallet appendixes 16. After the formation of the windings 18, the pallet is again turned through 90 degree and is rested on the belts 13, along which it advances towards the termination station 31 (Fig. 4) where the ends of the wires 17 are fixed to the relative terminal means in known manner. It is also advantageous in this station to provide the device 21 for rotating each pallet in order to position the stator with its axis horizontal, i.e. in a position suitable for fixing the wires 17, an operation which can be carried out in conventional manner with conventional machines. It may be advantageous to rotate the pallet through 90 degree as shown in Fig. 3 at other stations along the line, both to make the station itself of simpler construction and to maintain high stator production. It is in any event superfluous to give further examples of working stations which can require this stator movement, as the movement will always be of the type illustrated with reference to the winding formation station 20.

Claims: A production line for components of an electric motor, which production line includes a plurality of working stations therein and a conveyor belt in proximity to the working stations for advancing the components from station to station; a plurality of pallets rigidly, fixedly, individually supporting the components thereon during movement of said components from station to station; characterized in that the production line is adapted for the production of stators and it comprises pivoting means (22, 28) in proximity to the stator working stations (20) for lifting said pallets (11, 12) from the conveyor belt (13) and pivoting them transversely to the belt so that the respective stators (10) become disposed in positions corresponding to the working stations (20) located along the production line, whereby the pivoting means (22, 28) are so designed that the pallets (11, 12) can be returned to the belt after working in the stations. A production line for electric motor stators according to claim 1 characterized in that the pallets include a base (12), which slides on said conveyor belt (13), and an upwardly extending cylindrical hollow body (11) within which the stator (10) is fixed; appendices (16), extending from said body (11), being arranged to temporarily receive the ends of wire windings (17) formed on the stator (10) at one of the stator working stations (20). A production line for electric motor stators according to claim 1 characterized in that the stators (10) are mounted on said pallets (11, 12) with their axes substantially vertical and in that the rotation of said pallets with said pivoting means (22, 28) is lateral to the line in order to position the stators (10) with their axes substantially horizontal and perpendicular to the axis of the line. A production line for electric motor stators as claimed in claim 1 or 3 characterized in that the pivoting means (22, 28) which carry out the lateral rotation of the pallets, consists of an arm (22) provided at its ends with jaws (27) for gripping the cylindrical body (11) of the pallet; said pivoting means (22, 28) further including drive means (25) for rotating the arm (22) through 90 degrees between a horizontal end position and a vertical end position, and for causing the jaws (27) to selectively close and open.

Inventors: LUCIANI, SABATINO, SANTANDREA, LUCIANO
Applicants: AXIS S.P.A.
Application year: 1986
Main classification: H02K15
IPC codes: H02K15