Patent Publication Number: US-2019189321-A1

Title: Electromagnetic device and manufacturing method thereof

Description:
BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     From a general viewpoint, the present invention relates to an electromagnetic device comprising at least one wound electric wire, such as a solenoid and/or an electromagnet and/or an electromagnetic coil, or the winding of an antenna and/or an inductor for an electronic circuit and/or the winding of an electric actuator or motor. 
     2. The Relevant Technology 
     Preferably, the device according to the invention belongs to an electromagnetic actuator of an electrovalve, particularly for apparatus or systems for injecting a fluid, e.g., an apparatus or system for injecting fuel and/or additive for combustion or endothermal engines and/or vehicles. The present invention also relates to at least one method or process for manufacturing and/or assembling said device. 
     As is known, some electromagnetic devices comprise a body or reel whereon an electrically conductive wire is wound, typically a copper wire covered with electrically insulating material, such as enamel or resin, e.g., polyurethanes, polyestherimide, polyamide-imide, polymide. 
     To the reel, electric terminals are typically fastened for creating an electric connection, hereafter also referred to, for brevity, simply as “terminals”; said terminals are typically provided with shaped portions useful for establishing a mechanical and electrical connection with the ends of the electrically conductive wire or conductor, hereafter also referred to, for brevity, simply as “wire”. 
     The ends of the wire can be fastened to the electric terminals by mechanical deformation of portions of the terminal itself and/or by soldering, e.g., electric soldering and/or soldering by addition of soldering material or metal alloy. In order to allow the wire to be wound on the reel and to be fixed to the electric terminals by automatic machines, the electric terminals include portions acting as fastening points for the electric wire, which extend in a direction substantially perpendicular to a longitudinal axis of the winding of the coil and/or solenoid. 
     In particular, the terminals provide some clearance around said fastening portion to allow the wire to be wound, in particular by means of a wire guiding element moving around said fastening portion. 
     Some examples of electromagnetic windings mechanically and electrically fastened to fastening portions of electric terminals in accordance with the above explanation have been known for decades, as demonstrated by German patent publication no. DE3615806 and utility model publication no. DE8700157U, to which reference should be made for further details. 
     In such known devices, after the conductive wire has been wound on the reel and the ends of the wire have been fastened to the electric terminals, a protective body or layer is added to cover the winding and at least part of the electric terminals, e.g., an overmoulded insulating protective covering body made of a plastic, thermoplastic, polymer or resin material. 
     Some examples of overmoulding of electromagnetic windings in accordance with the above explanation are known in the art, such as those described in International patent application WO 01/96086 and European patent application EP1614518, to which reference should be made for further details. 
     In other known devices, the protective covering body of the electric wire and/or solenoid and/or terminals forms at least part of the body of an electromagnetic device, such as a fuel injector; for an example of this state of the art, reference should be made to United States patents or applications U.S. Pat. No. 5,185,919, US2007/0290447, U.S. Pat. No. 5,823,445. 
     The process for manufacturing the electromagnetic device referred to herein substantially requires the presence of a clearance zone around the fastening portion for fastening the electric wire to the corresponding terminal, in particular a clearance zone between the body or reel whereon the wire is wound and said fastening portion of the terminal, in order to allow winding at least a part of an end of the electric wire. 
     Usually the process employed for manufacturing electromagnetic devices known in the art is carried out by an automatic apparatus fitted with at least one mobile wire guiding element of the type adapted to move along predefined paths under the control of an electronic control system; during the process, the reel with the terminals and the wound wire is then covered or overmoulded, at least partly, with a polymer, such as a thermoplastic material or a thermosetting material or a resin. 
     The known product thus obtained, i.e., the electromagnetic device comprising a coil or winding, is not however exempt from reliability risks that may impair the function it is intended for, particularly when the wire size is small or capillary, as is the case of certain coils for injectors to be used in engines or vehicles. 
     In fact, the present Applicant observed that, at least as concerns coils with an electric wire size smaller than 0.2 mm, particularly of the type with a wire diameter in the range of 0.15 mm to 0.16 mm, during the cover moulding or overmoulding operations mechanical stress arises which may cause the electric wire to break, leading to a large number of discarded parts; furthermore, such mechanical stress may cause latent damage that may not be detected during the production process, revealing itself only after some time in products already sold. In particular, this may occur in case of use of the product in extreme conditions, such as the use in a combustion engine or vehicle, or in the presence of vibrations and/or wide temperature variations, which also cause thermal expansion and/or contraction in the coil materials. The Applicant also verified that this risk is even higher in electromagnetic devices to be used in critical conditions, such as electromagnetic devices installed in vehicles and/or vehicle engines and/or endothermal engines in general, which are subject to high thermal stress and/or mechanical stress, such as vibration, acceleration, shocks and the like. 
     It was also verified that said risk condition is more frequent when the electromagnetic device is applied to at least one electrovalve of a line or apparatus for injecting fuel or additive into an endothermal engine and/or an exhaust system and/or an emission control system, or anyway in environmental conditions wherein the device is subject to wide temperature ranges, e.g., when an engine is started in cold weather conditions, which may be below 0° C. (e.g., as low as −40° C.), followed by fast heating to temperatures in excess of 100° C. (e.g., up to +125° C.), and then the engine is turned off and cools down again (−40° C.). Let us consider, for example, an endothermal engine of a vehicle or an electric generator or an air compressor exposed to winter or arctic environmental conditions. 
     Such temperature changes cause mechanical stress, also referred to as “thermal stress” or “thermal shock”, adding to the mechanical stress induced by the engine vibration: all these stresses will be transmitted, whether directly or indirectly through other parts, to said electrovalve for injecting or feeding fuel or additive into the engine and/or exhaust system. 
     The Applicant also verified, surprisingly, that such mechanical stress and the resulting risk of failure of the electric wire grows higher in those areas where the protection covering or overmoulding is thicker, particularly in that wire portion which crosses at least partly the protective cover that fills said clearance zone for winding the wire around the electric terminal, such as the covering or overmoulding part in the clearance zone between the reel and the wire fastening portion. 
     The Applicant originally thought that, in order to improve the state of the art, such risks of malfunction can advantageously be eliminated or reduced and/or the performance of the aforesaid electromagnetic devices can be improved. 
     A general technical problem at the basis of the present invention is therefore to overcome the above-described problems of the prior art. 
     A further technical problem addressed herein is to make the operation of the electromagnetic device reliable, independently of the production conditions and/or of the apparatus with which it may be associated, i.e., regardless of the conditions of use. 
     Another technical problem addressed herein is to provide a device which proves to be reliable even when covering or overmoulding materials are used which are characterized by relatively high shrinkage, e.g., during the moulding process in the production cycle, and/or by high thermal expansion and/or contraction, e.g., in operating conditions. 
     A general idea that solves the above-mentioned technical problems is to improve the safety and/or reliability and/or performance of electromagnetic devices, in particular of devices such as electromagnetic valves and/or actuators and/or motors, or anyway of devices including electric windings, such as a solenoid and/or an electromagnet and/or an electromagnetic coil. 
     According to a further aspect, another solution proposed by the invention is to improve the safety and/or reliability and/or performance of a coil and/or an electrovalve for apparatus or systems for injecting a fluid, such as an apparatus or system for injecting fuel and/or additive for combustion or endothermal engines and/or vehicles. 
     According to a further, more specific aspect, the invention aims at providing an electromagnetic device of the type considered above, which has such structural and/or functional characteristics as to prevent or reduce the risk of failure of the electric wire of an electromagnetic device. 
     The invention also comprises a method or a process for manufacturing and/or assembling an electromagnetic device, such as a coil and/or an electrovalve and/or an actuator, or the like, for apparatus in general, and in particular for apparatus for injecting fuel or additive into internal combustion or endothermal engines and/or exhaust systems and/or emission control systems. 
     In order to implement this solution to the above-mentioned technical problem, the invention teaches to arrange additional or auxiliary means or elements or inserts, for supporting and/or protecting the electric wire and/or for reducing the thickness of the covering material, along at least part of the path followed by the wire, preferably in the areas subject to the risk of damage, such as said clearance zone between the reel and the fastening portion where the electric wire is secured to the electric terminal; said means or elements or inserts will hereafter also be referred to as “additional means” or “additional inserts” or simply as “inserts”. 
     One inventive idea is to arrange additional means for supporting that section of electric wire which extends in the areas subject to risk of breakage or damage, such as said clearance zone, in particular between the reel and the fastening portion where the electric wire is secured to the electric terminal, preferably for the purpose of creating support zones for the wire between the reel and the electric terminal. 
     A further inventive idea is to arrange additional means for protecting that section of the electric wire which extends through areas subject to the risk of breakage or damage, such as said clearance zone, i.e., between the reel and the fastening portion where the electric wire is secured to the electric terminal, particularly for the purpose of protecting the electric wire against the thrust exerted by the covering material during the moulding process steps, preferably carried out by injecting a polymer or a thermoplastic or thermosetting material or a resin into a mould, into which the reel has been previously inserted, with the electric wire wound thereon and secured to the electric terminals. To this end, the mould is preferably so designed that the material flow is injected into predefined points and arrives at the electric wire that needs to be protected and/or at the clearance zone from such a direction that the electric wire will be shielded or protected against the flow, or anyway with a predefined flow in a direction that will optimize the protection function of said additional means, such as a flow at least partly shielded or diverted by at least one wall of the additional means. 
     Preferably, additional means are used which can support the wire in such a way as to counter the thrust exerted by the flow of moulded material and/or which can protect the wire by diverting the flow of moulded material. 
     The provision of additional means for protecting or shielding and/or supporting the wire facilitates the moulding, while possibly also allowing the use of higher pressure and/or speed for injecting and diffusing the fluidic polymeric material into the mould, particularly for the purpose of reducing the moulding cycle time, thus reducing the cost of the device  1 . 
     Another inventive idea is to arrange additional means for reducing the thickness of the covering or overmoulding material in the areas subject to risk of breakage or damage, such as said clearance zone, in particular between the reel and the fastening portion where the electric wire is secured to the electric terminal, preferably for the purpose of creating a thinner covering or overmoulding layer in the areas crossed or occupied by the electric wire between the reel and the electric terminal. 
     Advantageously, additional supporting and/or protective and/or thickness-reducing means are preferably arranged, at least partly, between the reel or inductive winding and portions for fastening or connecting the wire to the electric terminals. 
     In accordance with a particular solution to the technical problem, the additional means are fixed or coupled, at least partly, to at least one of the reel and at least one electric terminal, preferably for the purpose of at least facilitating the handling operations during the production cycle; to this end, coupling and/or engaging means are provided, which are at least partly formed on the additional means and/or at least partly formed on the reel and/or the terminals, such as coupling and/or engaging means operating by interference and/or hooks and/or rises and/or seats. 
     In accordance with a further solution to the technical problem, the additional means are provided with fixing elements to be secured to the covering body, for fixing or positioning the additional means by means of the covering material and/or by injecting or overmoulding the protection material onto at least one of the reel and at least one electric terminal, particularly at finished device level. Said fixing elements are, for example, rises or seats covered or filled, at least partly, with the covering or overmoulding material, such as lateral reliefs in the form of inclined planes or steps. 
     According to one inventive aspect, the electromagnetic device comprises or is fitted with an additional or auxiliary element made from polymer, such as a polyamide (PA), particularly of the PA6 and/or PA66 types, or a polybutylenterephthalate (PBT) or a polyphenylensulfide (PPS), preferably with the addition of a reinforcement additive or filler, such as fiberglass, e.g., in a quantity of 35%. 
     According to a further inventive aspect, the additional element is made from a polymer suitable for mechanically and/or chemically binding to the covering or overmoulding material, preferably by mutual melting or bonding during the overmoulding process; preferably, the additional element and the covering comprise at least one of a polyamide (PA, PA6, PA66) or a polybutylenterephthalate (PBT) or a polyphenylensulfide (PPS) or a thermosetting polymer, such as an epoxy resin, preferably with the addition of an additive or filler, such as fiberglass, e.g., in a quantity of 35%. 
     According to a further inventive aspect, the covering or overmoulding material is adapted to promote adhesion and/or chemical binding (such as a covalent and/or ionic or ionic-bridge bond) to the material of the additional element and/or the reel, or between the covering material and the material of the additional element and/or the reel an adhesion promoting material or substance (primer) is interposed, which creates a thin intermediate layer, preferably having a thickness of 1 microns to 20 microns, suitable for causing said materials or parts of the device to adhere and/or bind chemically to each other. 
     The features of the invention are more specifically set out in the claims appended hereto, which are an integral part of the description and/or of the technical teaching of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Such features, the effects resulting therefrom and/or the advantages of the invention will become more apparent in the light of the following description, in which reference will be made to the annexed drawings, which are supplied by way of illustrative and non-limiting example, wherein: 
         FIGS. 1 and 2  are axonometric views of an electromagnetic device according to the invention, in respective conditions turned by 180° relative to a longitudinal axis; 
         FIGS. 3 and 4  are, respectively, a top view and a front view of the device of  FIGS. 1 and 2 ; 
         FIGS. 5 and 6  are, respectively, a bottom view and a side view of the device of the preceding figures; 
         FIGS. 7 and 8  are axonometric views of the above device with a part thereof removed, in respective conditions turned by 180°; 
         FIGS. 9 and 10  are views from respective angles of the above device and an additional means or insert according to the invention; 
         FIGS. 11 and 12  are axonometric views from different angles of some distinct parts of the device according to the invention; 
         FIGS. 13 and 14  are axonometric views from respective angles of a first example of an additional means or insert of the device of the preceding figures; 
         FIGS. 15 and 16  are axonometric views from different angles of a detail of the device according to the invention; 
         FIGS. 17 and 18  are axonometric views from different angles of a detail of a second example of the device according to the invention; 
         FIG. 19  schematically shows some steps (A), (B), (C) of the process for making the device of the preceding figures; 
         FIGS. 20, 21 and 22  are magnified views of respective parts of the device of the preceding figures; 
         FIGS. 23 and 24  show further magnified views from different angles, with a part removed, of a detail of the device according to the invention; 
         FIGS. 25 and 26  schematically shows respective steps of the process for making the device of the preceding figures. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before proceeding any further with a detailed description, it must be pointed out that particular configurations, structures or features described herein as non-limiting examples may be considered individually or combined as deemed appropriate in one or more embodiments, even different from those exemplified herein. Also, the references below are therefore used only for simplicity&#39;s sake and do not limit the protection scope or extent of the various embodiments. Any numerical and spatial references and/or definitions such as “upper”, “lower”, “on”, “under”, “high”, “low” refer to the exemplary drawings and should not be understood as limitations. 
     With reference to the drawings,  1  designates as a whole a preferred example of a device according to the invention, such as an electromagnetic device comprising at least one wound electric wire, in particular a solenoid or an electromagnet or an electromagnetic coil, preferably being a part of an electromagnetic actuator of an electrovalve or an injector, in particular intended for use in apparatus or systems for injecting fuel or additive into combustion or endothermal engines of vehicles and/or exhaust systems and/or emission control systems. 
     The device  1  according to the invention comprises at least one element or reel  100  for winding and/or supporting an electric wire, wherein a central or support body  101 , typically cylindrical and axially hollow, is delimited at its ends by two walls or flanges  102  and  103 , i.e., a rear first one and a front second one with reference to the drawings ( FIGS. 7 and 8 ). 
     Alongside at least the front flange  103  of the reel  100 , such as the front flange  103  shown in  FIG. 7 or 8 , there is a front wall or face  109  from which a portion of appendix or protrusion  106  extends in a cantilever fashion; preferably, the portion of appendix or protrusion  106  extends from the front flange  103  and/or from the front face  109  in a direction substantially orthogonal thereto and/or parallel to the longitudinal axis X-X of the reel, though it may also extend radially or anyway inclined relative to said axis. 
     In accordance with a preferred embodiment, the appendix  106  comprises at least one pair of side walls  106   a,    106   b  and a front wall  106   c  (see  FIGS. 7, 8 and 15 ). 
     As will become more apparent below, the appendix  106  is configured in an advantageously original way, since it includes a series of elements, such as walls, channels, seats, etc., that require a detailed explanation. Proceeding in the right order and starting from the above-mentioned front wall  106   c,  coupling means  111  (more visible in  FIG. 12 ) are advantageously provided thereon to be coupled to electric terminals  200 , i.e., to respective first and second terminals  200   a  and  200   b.    
     The front wall  106   c  can preferably also act as an abutment element for the intermediate portions  210   a,    210   b  of the electric terminals  200   a,    200   b,  when their coupling ends  203   a,    203   b  are inserted in the apertures  111 . 
     In the example shown, the front wall  106   c  is flat and the coupling means  111  essentially consist of seats or holes formed in the front wall  106   c,  where the terminals  200   a,    200   b  can be mechanically secured by insertion and/or driving and/or fitting into a corresponding fastening end  203   a,    203   b.    
     The fastening ends  203   a,    203   b  are so shaped or configured to ensure a stable engagement with the coupling means  111  of the reel  100 ; in the example shown, the fastening ends  203   a,    203   b  are configured with a substantially T-shaped head, but they may be made differently, e.g., shaped like an arrow or a hook, or with at least partially inclined or rounded profiles, or the like. 
     Likewise, the front wall  106   b  may not be flat as shown herein, but, for example, at least partially inclined or concave or convex, or may comprise distinct levels and/or cavities and protrusions, possibly in order to create at least part of a fitting or joint to be coupled to another element of the device; the front wall  106   c  is then preferably shaped in such a way as to also match the shape of at least some surfaces of an abutment edge  211   a,    211   b  ( FIGS. 11 and 12 ) of the terminals  200   a,    200   b.    
     It must also be pointed out that the terminals  200   a,    200   b  can be fixed to the reel  100  in a different way and/or in another position, not necessarily on the appendix  106  thereof (which may even be absent or anyway have a different configuration than shown). 
     For example, the terminals  200   a,    200   b  can be fixed by moulding or overmoulding the reel  100  on the respective fastening end  203   a,    203   b  of the terminals  200   a,    200   b.    
     In this regard, it must be pointed out that the body of the reel  100  is preferably made of an electrically insulating material; to this end, it is advisable to use a polymer or a plastic material or a mouldable material, such as a thermoplastic or thermosetting material or a resin, preferably a polyamide (PA), particularly of the PA6 and/or PA66 type, or a polybutylenterephthalate (PBT) or a polyphenylensulfide (PPS), preferably with the addition of an additive or filler, such as fiberglass, e.g., in a quantity of 35%. 
     For brevity, the material of the reel  100  and/or of parts of the device  1  will hereafter be referred to simply as “plastic material” or “polymeric material” or “synthetic material” or “polymer” and the like, such definitions having to be understood in a broad sense to include the previously mentioned materials and/or thermosetting materials and resins, in addition to polymers and thermoplastic materials. 
     Referring back to the appendix  106  of the reel  100 , it comprises a pair of walls or wings  113 ,  114  that extend laterally on opposite sides relative to a median plane of the device  1  passing through the longitudinal axis X of the reel. 
     In accordance with a preferred embodiment, the wings  113 ,  114  have a bent configuration or are inclined at different angles, so as to define, together with the side walls  106   a,    106   b  of the appendix  106 , corresponding lateral channels  115 ,  116  extending along the flanks of the appendix  106 . 
     The longitudinal extension of the wings  113 ,  114 , designated as “L” in  FIG. 9 , is substantially similar to that of the corresponding side walls  106   a,    106   b  of the appendix  106 , and/or at the front, i.e., at the end facing towards the terminals  200 , the wings  113 ,  114  terminate at a shoulder or wall  118  of the appendix  106 , from which a head  120  extends. 
     Said head  120  is a component that provides a shape coupling with at least a part of an insert  500 , corresponding to the previously defined additional or auxiliary support and/or protection means or elements or inserts, which will be further described below; it must nevertheless be observed here that the head  120  of the appendix  106  is frontally delimited by the front wall  106   c,  where there are the holes  111  for the connection to the electric terminals  200   a,    200   b.    
     Furthermore, the head  120  of the appendix  106  comprises a series of side walls  106   d,    106   e,    106   f,    106   g,  . . .  106   n,  which are preferably flat and oriented according to a polygonal line, as shown in  FIG. 22 ; the function of such walls will become apparent below, but here it must be pointed out that they may also be curved or anyway not flat. 
     The electric terminals  200   a,    200   b  are preferably made of an electrically conductive material; for this purpose, it is preferable to use a copper-based alloy, such as a phosphorous bronze alloy or a CuSn6 alloy, which typically comprises copper and approx. 6% tin; the electric terminals are preferably sheared from a strap and/or shaped and then coated with a tin layer. 
     The first and second terminals  200   a,    200   b  comprise respective contact ends  201   a  and  201   b,  adapted to create an electric connector towards an external wiring, not shown in the drawings; said terminals  200   a,    200   b  preferably extend parallel to the axis X of the device. 
     In accordance with a preferred embodiment, the electric terminals  200  have a tapered configuration towards the contact ends  201 , preferably comprising or being associated with an intermediate portion  210  that is wider than the fastening ends  203  and the contact end  211 . 
     Transversally to each intermediate portion  210   a,    210   b  of the terminals  200   a,    200   b,  a respective electric connection or fitting lug  202   a  and  202   b  extends, which is adapted to establish e mechanical and/or electrical fastening of the wires or ends  301  and  302  of the winding  300 . 
     Advantageously, on each fastening or fitting lug  202   a,    202   b  there is a respective slot  204   a,    204   b,  which is substantially straight and transversal to the terminals  200   a,    200   b.    
     The slots  204   a,    204   b  separate respective reliefs or flaps  205   a,    205   b  and  206   a,    206   b  of the corresponding lugs or fittings  202   a,    202   b;  advantageously, the thickness of the latter or of some flaps  205 ,  206  is such that, as will be explained below, they can be bent or anyway deformed to allow fastening the ends of the electric wire. 
     The terminals  200  and/or said intermediate portion  210  further comprise seats and/or apertures and/or holes and/or notches and/or undercuts  207 ,  208 ,  209  for fastening other elements, e.g., mounted and/or overmoulded ones, as will be explained below; it should also be pointed out here, for clarity, that in this description and in the drawings the elements associated with the first terminal  200   a  are designated by letter “a” (e.g.,  207   a,    208   a,    209   a ), while those associated with the second terminal  200   b  are designated by letter “b” (e.g.,  207   b,    208   b,    209   b ); however, said elements are also designated, in general, by the same reference numerals with no letter. 
     Along the body of the reel  100 , near the terminals  200   a,    200   b,  respective clearance zones  107 ,  108  can be identified, which are comprised between the shoulder or wall  118  of the appendix  106  and the corresponding fitting lug  202   a,    202   b  extending in a cantilever fashion from the intermediate portions  210   a,    210   b.    
     In these clearance zones  107 ,  108  the respective end portions  301 ,  302  of the electric wire  300  of the coil winding run, which are secured to the aforementioned lugs or fittings  202   a,    202   b;  for this purpose, it is worth providing some details about how the wire  300  is applied onto the reel  100 , with particular reference to  FIG. 19 . 
     There is shown the device  1  in a condition in which the wire end  302  has already been fastened to the respective fitting lug  202   b  and the wire  300  has already been wound on the central body  101  of the reel  100 . 
       FIG. 19  concerns, therefore, the fastening of that end which will be defined herein, for simplicity, as first end  301  (in order to distinguish it from the other one, which will be defined as second end  302 ). 
     Note that the fastening of both ends  301  and  302  of the wire occurs in the same way; therefore, what is illustrated in  FIG. 19  for the first end  301  is also applicable to the second end  302 , and vice versa. 
     Therefore, as shown in  FIG. 19 , the end  302  of the wire is already in the condition in which it is fastened to a corresponding fitting lug  202   b  of the electric terminal  200   b;  for this purpose, it has been wound around the base of the lug  202   b  at the seat or cavity  209   b,  then secured by inserting its end into the slot  204   b  of the lug  202   b  and fixed by deforming the flaps  205   b,    206   b  of the latter. 
     This latter step is carried out by an operator by using a tool such as pliers, or mechanically by a press. 
     To ensure electric contact, the end  302  of the wire is soldered to the terminal  202   b,  preferably by electric soldering or spot-soldering. 
     Still with reference to the condition of the device  1  shown in  FIG. 19 , after the end  302  has been fastened to the respective terminal  200   b,  the wire  300  is run into the channel  116  alongside the appendix  106  and wound on the central body  101  of the reel  100 , in order to create the actual wire coil, and the wire is then run into the channel  115  towards the electric terminal  200   a.    
     It is at this point that the wire end  301  is fastened to the corresponding fitting lug  202   a  of the electric terminal  200   a:    FIG. 19  specifically shows three different instants (A), (B), (C) of the part of the process for manufacturing the device of the invention. 
     In particular, as can be seen, in order to execute this production phase the electric wire  300  is preferably associated with a wire guide  401  and its end  301  is wound around the base of the lug  202   a  at the cavity or slot  209   a,  forming a number of loops (typically three or four, depending on the diameter of the wire  300  and the size of the cavity  209 ) sufficient to ensure that it will be fastened permanently. 
     The end  301  of the wire  300  is applied onto the lug  202   a  at the cavity  209   a  by shuttling the wire guide  401 , which will make a few turns around the lug  202   a  by moving back and forth between the clearance zone  107  and the front zone near the tip  201   a  of the terminal. 
     As can be guessed from  FIG. 19 , the terminal portion  302  of the wire  300  that is present before the wire is wound on the reel  100  is secured to the fitting  202   b,  and is wound at the cavity  209   b  in the same way as previously described in regard to the fastening of the end portion  301  to the fitting  202   a.    
     At this stage, the wire guide  401  makes a revolving motion around the fitting lug  202   b,  moving back and forth between the clearance zone  108  and the front zone of the terminal  200   b.    
     As aforesaid,  FIG. 19  schematically shows respective steps (A), (B), (C) of application of the end  301  of the wire onto the fastening lug or fitting  202   a  of the electric terminal  200   a,  starting from a condition in which the other end  302  of the wire has already been fastened to the respective fastening lug  202   b  and the wire  300  has been wound as a coil on the reel  100 . 
     In this respect, it is worth mentioning that, as previously explained, also the end  302  of the wire  300  is applied by means of a wire guide  401 , which makes a few turns around the lug  202   b  by passing through the clearance zone  108 . 
     According to a preferred example, the wire guide  401  comprises a tube-shaped portion (e.g., having an outside diameter of 1.2 mm and an inside diameter of 0.6 mm for use with an electric wire having a diameter smaller than 0.3 mm), at least one end  401   a  of which moves in the clearance zones  107  or  108 , depending on the steps of the process for manufacturing the device  1  previously described with reference to both ends  301  and  302  and to  FIGS. 19(A) , (B), (C), turning about the fitting lug  202   a,    202   b  of the terminals  200   a,    200   b.    
     For this reason, the size of the clearance zones  107 ,  108 , which are comprised between the shoulder  118  at the ends of the channels  115 ,  116  and the lug  202   a,    202   b,  is such as to allow the wire guide  401  to pass as it turns to wind the ends  301 ,  302  of the wire on the cavity  209   aa,    209   b  of the lug. 
     According to a preferred version of the device of the invention, the axial extension of said clearance zones  107 ,  108  relative to the axis X, i.e., the distance between the shoulder  118  of the appendix  106  of the reel  100  and the fastening or fitting lug  202   a,    202   b  is greater than 1.3 mm, being preferably comprised between 1.5 mm and 10 mm, particularly between 1.8 and 2.2 mm. 
     For this purpose, the dimensions of the wings  113 ,  114  and/or of the side walls  106   a,    106   b  of the appendix  106 , as well as those of the respective channels  115 ,  116  defined by them, can be advantageously so defined as to keep said extension of the clearance zones  107 ,  108  within optimal values as a function of the electromagnetic device  1  to be manufactured. 
     Advantageously, the wings  113 ,  114  and the channels  115 ,  116  perform also the function of housing and/or partially protecting the corresponding ends S 1 , S 2  and/or  301 ,  302  of the wire  300 . 
     The ends  301 ,  302  of the wire  300  extend, with respect to the shoulder  118  of the appendix  106  of the reel  100 , through the clearance zones  107 ,  108  to be then fastened to the respective fittings  202   a,    202   b,  and therefore they have respective portions or sections S 1 , S 2  exposed to stress caused by the flow of polymer or melted plastic injected during the moulding process. 
     Moreover, in addition to the above-mentioned length L, the channels  115 ,  116  have a width and/or a shape that allow the wire  300  to be properly positioned when it is wound on the respective fastening or fitting lug  202   a,    202   b  of the electric terminals  200 . 
     The width and/or the shape of the channels  115 ,  116  also depends, among other things, on the distance between the side wall  106   a,    106   b  and the corresponding wing  113 ,  114 . 
     In this context, it is possible to appreciate the importance of the clearance zones  107  and  108 , which allow the wire guide  401  to pass around the respective fitting  202   a,    202   b  of the terminal  200 ; however, this inevitably implies the presence of a section of wire, such as the sections S 1 , S 2 , that is “suspended” through the clearance zones  107 ,  108 , i.e., between the shoulder  118  of the appendix  106  and the respective lugs or fittings  202   a,    202   b.    
     This suspended section, designated as “S 1 ” and “S 2 ”, is therefore exposed to the risk of breakage during the subsequent moulding or overmoulding of the plastic or polymeric material on the winding and/or the subsequent use of the product. 
     In fact, once the wire  300  has been applied and the ends thereof  301 ,  302  have been fastened, the coil is coated with electrically insulating material  400 , such as a thermoplastic or thermosetting polymer, preferably by overmoulding it thereon; such material is typically injected as a fluid at a predefined pressure, and typically undergoes some dimensional shrinkage during the cooling step that follows the moulding step, said dimensional shrinkage being proportional to the thickness or mass of the moulded material. 
     The Applicant observed that in the clearance zones  107  and  108 , i.e., in the regions where the wire guide  401  passes when the ends of the wire  300  are applied onto the fittings  202   a,    202   b  of the electric terminals  200 , a relatively high accumulation of overmoulded material  400  occurs, which envelops the tract or section S 1 , S 2  of wire suspended in said clearance zones  107 ,  108 . 
     This causes particularly high shrinkage and/or dimensional variations, especially during the production process, which directly act upon said suspended tract or section S 1 , S 2  of wire extending between the reel and the terminal through said clearance zone  107 ,  108  and which will cause it to break immediately or anyway to undergo damage that may cause the wire to break and/or suffer performance reductions at a later time. 
     It should be considered, in fact, that even if the wire does not break immediately, strain or stress may arise which might create latent damage, i.e., partial damage, to the electric wire, e.g., by squeezing and thinning the electric wire and/or inducing strain or stress in the metal of the electric wire, or even just by damaging the insulating enamel or covering of the wire. As aforesaid, such latent damage may cause the wire to break in the long run, particularly in the case of small-gauge electric wires and/or devices used on engines and/or vehicles, i.e., devices subject to high stress, such as thermal stress and vibration. 
     In order to prevent such problems from arising, in the device  1  according to the invention there are additional means for protecting and/or supporting the wire  300  and/or the above-mentioned suspended tracts or sections thereof S 1 , S 2 . 
     In accordance with a preferred embodiment of the invention, such additional protection means comprise at least one additional insert or element  500 , hereafter also referred to, for brevity, simply as “insert”, which is adapted to cover and/or protect and/or support, at least partially, those portions of electric wire  300  that are most subject to the risk of breakage or damage, such as the suspended sections S 1 , S 2  and/or at least parts of the ends  301  and  302 , etc. 
     In fact, the invention teaches to provide protection means adapted to achieve one or more specific and advantageous effects. 
     In the case of the additional insert or element  500 , such effects include constituting at least one respective wall of diaphragm or septum for protecting and supporting the suspended wire tracts S 1 , S 2 . 
     Said diaphragm is preferably configured to be physically interposed between the suspended wire sections S 1 , S 2  and the flow of melted and/or fluidic and/or liquid polymer or plastic material that is injected into the mould during the moulding process. 
     Said wall or diaphragm of the additional insert  500  is preferably configured to support the suspended sections S 1 , S 2  of the electric wire  300 , e.g., to counter a thrust exerted on said wire portion by the flow of polymeric material injected into the mould. 
     In a preferential configuration, the wall or diaphragm or septum provides a two-fold protection by shielding the wire tract in the clearance zones  107 ,  108  against a direct flow injected into the mould, which flow is diverted in the mould but then hits again on the opposite side, though indirectly, the suspended wire tracts or sections S 1 , S 2  in the clearance zones  107 ,  108 , where the wire is supported by the wall or diaphragm, which counters the thrust exerted by the fluid injected into the mould. Therefore, said wire shielding and supporting actions cooperate to prevent failures caused by the thrust exerted by the moulding material. 
     Preferably, the additional insert or element  500  also contributes to reducing the thickness of the covering material  400 , in particular in said clearance zones  107 ,  108  where the suspended sections S 1 , S 2  of the wire ends  301 ,  302  extend. 
     In other words, the additional element  500  is not only a diaphragm physically supporting and/or protecting the suspended wire sections S 1 , S 2  against the flow of fluidic polymer or melted plastic during the moulding process, since it preferably also causes a reduction in the mass and/or thickness of the layer  400  of moulded polymer or plastic material along at least a part of the end portions or ends of the wire that extend in said clearance zones  107 ,  108  comprised between the wall or shoulder  118  of the appendix  106  of the reel  100  and the fastening lugs or fittings  202   a,    202   b  of the electric terminals  200 . 
     Therefore, it follows that, in these locations, the reduction in the mass and/or thickness of the overmoulded material also leads to a reduction in the shrinkage or dimensional settling of the moulded polymer or plastic material, and hence to reduced stress or strain on the wire caused by such shrinkage or settling of the moulded material. 
     Within the scope of this general teaching of the invention, it will thus be possible to design the insert  500  in the most appropriate manner according to the circumstances; this is an important feature of the invention. 
     For example, the shape and size of the coil  300 , those of the electric terminals  200 , as well as the number thereof, those of the appendix  106 , and also other aspects, can be taken into consideration when determining the configuration of the additional element  500 . 
     The embodiment of the additional protection and/or support element  500  shown in the annexed drawings, in particular those from  13  to  18 , comprises two portions which are substantially symmetrical relative to the longitudinal axis X-X of the device, and which are adapted to be associated with and/or operate with reference to a respective part of the terminal  200   a,    200   b  and/or end of the electric wire  301 ,  302  and/or suspended section S 1 , S 2 ; however, two or more additional elements or inserts  500  may be used, each one associated with a respective terminal and/or a respective end  301 ,  302  of the electric wire and/or a respective suspended section S 1 , S 2 , such as an additional element or insert  500  of the type shown herein or the like, but divided into two parts, e.g., two symmetrical additional elements or inserts  500 . 
     The protection insert  500  (more visible in  FIGS. 13 and 14 ) is provided with a substantially fork-shaped body  501 , wherein two portions or arms  510  extend at the end of a central portion or core  511 . 
     The insert  500  comprises also fastening and/or coupling elements or means  502 ,  503 ,  504 ,  510 ; in this case, such means comprise protrusions or pins  502   a  and  502   b  or arms  510  that are engaged and/or coupled, preferably by interference, into respective seats or holes  207   a,    207   b  of at least one of the terminals  200   a,    200   b  and/or seats or rises  110  and/or walls  106   d,    106   e,    106   f,    106   g,  . . .  106   n  (visible in  FIG. 22 ) and/or seats or hooks defined by the appendix  106  of the reel  100 . 
     In addition or as an alternative to this, on the body  501  of the insert  500  there may be one or more rises or joints  503 , arranged centrally or interposed between the electric terminals  200   a,    200   b.    
     The rise  503  fits and/or engages, preferably by interference, into corresponding seats  208   a,    208   b  of at least one of the terminals  200   a,    200   b;  when these seats are not provided in the terminals  200 , the rise  503  can be configured otherwise to engage with the side walls of the terminals  200 . 
     Regardless of how the pins  502   a,    502   b  and/or the rise  503  or other elements are embodied, in the invention the fastening and/or coupling means of the insert  500  are preferably adapted to act also as spacers or positioning elements for the electric terminals, at least during the steps that precede the moulding of the covering  400 . 
     As can be seen, in fact, the pins  502   a,    502   b  have a predetermined pitch, so as to preferably keep the terminals  200   a,    200   b  apart while assembling and moulding the device  1 : in this manner, higher precision and better tolerances can be achieved to improve the quality of the industrial production of the device  1 . 
     Similar considerations also apply to the central rise  503 , which, being preferably interposed between the electric terminals  200   a,    200   b,  keeps them at a predefined distance; moreover, the rise  503  engages with the seats  208   a,    208   b  of the electric terminals  200   a,    200   b  and thus creates, de facto, a joint coupling that will accurately hold the same terminals parallel to each other, even while assembling and moulding the device  1 . 
     These advantageous effects are further promoted by the fact that, preferably, the fastening means of the insert  500  comprise also coupling elements  504 , e.g., teeth or hooks. 
     In a preferred embodiment, during the assembly operations such coupling means can bend elastically and then snap back into respective seats  110  located on the sides of the appendix  106  of the reel  100 . 
     According to one advantageous embodiment, when the insert  500  is mounted to the reel  100  (as visible, for example, in  FIG. 15, 16 or 17, 18 ), the coupling elements  504  and the seats  110  are on the side opposite to the pins  502  and/or the rise  503 , with respect to the fastening lugs or fittings  202   a,    202   b  of the electric terminals  200   a,    200   b,  or with respect to the front wall  106   c  of the appendix  106 , where coupling holes or seats  111  are formed. 
     This ensures a balanced distribution of the constraining forces that keep the insert  500  anchored to the appendix  106  of the reel  100 , since it extends across said front wall  106   c.    
     Finally, still with reference to the preferred example shown in the drawings, the body of the insert  500 , with its arms  510  and central portion or core  511 , circumscribes a mortise-shaped, or female-joint, seat  513  adapted to be coupled to the tenon-shaped, or male-joint, head  120  of the appendix  106  of the reel  100 . 
     For this purpose, the tenon-shaped head  120  and the mortise-shaped seat  513  are at least partly complementary to each other and have at least some complementary or facing walls adapted to mate together, particularly by interference; preferably, the head  120  and the seat  513  and/or the arms  510  create a joint having at least some inclined walls coupled together in a “dovetail” fashion, or other joints with mating shapes having at least partially curved walls or other suitably shaped walls. 
     Preferably, the joint seat  513  has, at its periphery, a series of walls  513   a,    513   b,    513   c,    513   d,    513   e,    513   f,    513   g,  . . .  513   n  (visible in  FIGS. 13 and 14 ) that have different orientations in accordance with a substantially polygonal line that is open at the front, where the free ends of the two arms  510  of the body of the insert  500  are positioned. 
     In the condition in which the insert  500  and the appendix  106  of the reel  10  are assembled together, such walls  513   a - 513   n  are juxtaposed to the walls  106   c - 106   n  of the head  120  of the appendix  106 . 
     As better shown in  FIGS. 13 and 14 , in this example the walls  513   a - 513   g  are oriented symmetrically, i.e., at least the walls  513   a - 513   c  are symmetrical to the walls  513   e - 513   g  with respect to a median plane of the body of the insert  500  passing through the longitudinal axis X-X of the device  1 . 
     Furthermore, the walls  513   a,    513   b e    513   f,    513   g, . . .    513   n,  i.e., those which are closer to the free ends of the arms  510  of the inserts, are inclined or converging and/or parallel; in addition, at least two of them, opposite to each other, are preferably adapted to determine a coupling interference with corresponding facing walls of the appendix  106  of the reel  100 . 
     In general, the engagement seat  513  preferably has at least two opposite walls of the two arms  510 , wherein at least one first wall  513   b,    513   c  is opposite to at least one second wall  513   e,    513   f,  which are inclined or diverging or converging, and/or wherein at least one wall  513   a  is parallel to an opposite wall  513   g,  particularly with respect to an axis parallel to the longitudinal axis X of the device  1 . 
     In a preferred version, the engagement or seat  513  comprises at least two walls of the same side or arm  510  which have two different inclinations, such as the two walls  513   b  and  513   c  and/or the two walls  513   e  and  513   f,  which have different angles of inclination, e.g., relative to an axis parallel to the longitudinal axis X. 
     In this way, the coupling between the tenon  120  and the mortise  513  is even more stable and accurate, thus facilitating the steps of assembling and moulding the device  1 . 
     As an alternative, the configuration or disposition of the male and female joints could be inverted. Thus, the tenon-shaped head  120  could be configured as a seat or mortise  120  to be coupled to a rise or tenon  513 , still having similar profiles or walls as previously described, i.e., said seats could become rises or male joints and, vice versa, the heads or male joints could become seats or female joints. 
     In accordance with a preferred embodiment of the invention, the insert  500  also has some portions or surfaces  514   a,    514   b  for bearing and/or supporting and/or protecting the respective ends or end portions  301 ,  302  of the electric wire, which extend in the above-mentioned clearance zones  107 ,  108 . 
     The bearing and/or protection and/or support surfaces  514  extend along the intrados of the arms  510  of the insert  500 , i.e., that side of said arms which, when the device  1  is in the assembled condition, faces towards the electric terminals  200 . 
     In accordance with a preferred embodiment, said bearing and/or support portions or surfaces  514  are laterally delimited by sides  515 , the latter being formed at the lateral edge of the arms  510 . 
     Advantageously, the sides  515  are arranged substantially at right angles or rise in a direction substantially orthogonal to the bearing and/or support surfaces  514  (see  FIG. 13 ), so that, when the insert  500  is applied onto the appendix  106  of the reel  100 , the insert  500  with its sides will not interfere with the suspended end portions S 1 , S 2  of the wire. 
     Furthermore, in a preferred embodiment the bearing and/or support surfaces  514   a,    514   b  and the sides  515   a,    515   b  are so configured as to substantially define a corresponding channel  516   a,    516   b  for the wire  300  and/or its end sections S 1 , S 2 ,  301 ,  302 . 
     Advantageously, the bearing and/or support surfaces  514  and the sides  515  are so arranged as to be substantially aligned with and/or to form extensions of the wings  113 ,  114 , so that also the respective channels  516   a,    516   b  of the insert will be aligned with and/or will form extensions of the channels  115 ,  116  of the appendix  106 , in particular in order to ensure longitudinal uniformity while supporting and holding the suspended sections S 1 , S 2  of the electric wire  300  during the handling thereof for winding and/or moulding purposes. 
     In this context, it must be pointed out that, advantageously, also the coupling means  504  contribute to delimiting, even only partially or for a limited length, the bearing surfaces  514   a,    514   b  on the side opposite to the sides  515 . 
     More generally, it can be stated that some parts of the insert  500 , such as said bearing and/or support and/or protection portions or surfaces  514 , the sides  515 , the coupling means  504   a,    504   b,  also act as lateral containment and/or protection elements for the suspended sections S 1 , S 2  of the wire  300  that extend in the zones  107 ,  108 , thus being at risk of breakage or damage. 
     This is particularly useful for protecting the electric wire against the thrust or flow of melted or liquid polymer or plastic material while moulding the covering  400 , as well as against the subsequent strain caused by shrinkage of the same material as it cools down and hardens. 
     Advantageously, the effect of protecting the suspended tracts S 1 , S 2  of the wire is amplified by the fact that, according to a preferred embodiment of the invention, the bearing and/or support and/or protection portions or zones  514  of the insert  500  are aligned with, or anyway are located along the extension line of, the guiding and/or protection and/or support channels  115 ,  116  that are present on the appendix  106  of the reel  100  (see details in  FIGS. 23 and 24 ). 
     This provides complete and uniform protection of the ends  301 ,  302  of the wire  300  against any stress that may arise during the moulding and/or the subsequent shrinkage of the polymer or plastic material, particularly starting from the front flange  103  or face  109  of the reel  100 , from which the appendix  106  extends, up to the electric terminals  200 . 
     It should be taken into account that, according to the prior art described at the beginning of the present description and according to the above explanation, if no means are provided for supporting and/or protecting the suspended wire sections extending in the aforementioned clearance zones, when the polymer or thermoplastic or thermosetting material is injected where the reel assembled together with the electric wire has been previously inserted, the mass of fluidic polymer will press against the suspended tracts of the electric wire, thus increasing the risk of failure thereof. 
     According to the teaching of the invention, on the contrary, the means for protecting and/or supporting the electric wire  300 , which in this case comprise the additional insert  500 , operate in such a way as to protect and/or shield and/or support the suspended sections S 1 , S 2 ; in the example shown herein, this is achieved by means of at least the surfaces  514  and, at least partly, the sides  515  and the coupling means  504 , but more generally other parts of the body  501  of the insert  500  can be exploited as well. 
     Preferably, this effect is amplified by injecting the material into the mould in such a way that the fluidic polymer or plastic material will mostly arrive from the side of the insert  500  opposite to that where the suspended sections S 1 , S 2  of the wire ends  301 ,  302  are located. 
     In this manner, an excessively direct or strong impact will be prevented between the fluidic mass of the moulded material and the suspended wire sections S 1 , S 2 : this will avoid, or minimize, the risk of breakage thereof due to the thrust exerted by the flow of said fluidic mass. 
     In this regard, it must also be pointed out that the pressure or thrust exerted by the fluidic mass is also compensated for by the protection or shielding and/or support surfaces  514  and by the sides  515  of the insert  500 , preferably in combination with the channels  115 ,  116  and the walls  113 ,  114  of the appendix  106  of the reel  100 , against which the suspended wire sections S 1 , S 2  can be pushed by the fluidic polymeric mass: the action of such surfaces will support the wire, which might otherwise break. 
     Finally, it should be reminded that the fluidic mass injection pressure exerts a thrust also on other components of the device  1  assembled in view of the moulding process, which might get slightly displaced from the initial condition during the process. 
     This is the case, for example, of the electric terminals  200 , which, although their ends  203  have been inserted into the holes  11  of the appendix  106 , can still move because of some inevitable play. 
     The present invention finds a remedy to this situation in that, as aforementioned, the engagement of the insert  500  with the electric terminals  200   a,    200   b,  provided by the pins  502  and/or the rise  503  or possibly other elements as well, will keep the electric terminals  200  accurately parallel to each other during the moulding step, thus ensuring a high-quality finished product. 
     In other words, it can be stated that the insert  500  can also be used as a mounting jig that will keep the assembled pieces of the device assembled together during the moulding process. 
     In addition to all this, it must be said that the above results also make for easier moulding, promoting the use of higher pressures and/or speeds for injecting and diffusing the fluidic polymeric material into the mould, particularly for the purpose of reducing the moulding cycle time and hence the cost of the device  1 . 
     In accordance with a preferred embodiment, the body  501  of the insert  500  has different heights or a tapered configuration, in particular starting from the arms  510  or wings  515  up to the central core  511  and/or its anchoring tabs  530 ; in the assembled condition, the thickness of the insert  500  preferably decreases progressively from the front wall  109  of the reel to the free end with the front wall  106   c  of the appendix  106 . 
     Preferably, said tapered configuration facilitates the fixing of the insert  500  by the fluidic polymeric mass. 
     Assembling an insert  500  in the front region of the appendix  106  will reduce the mass of moulded material in that region, thus also reducing said risk of damage. 
     According to a preferred embodiment, the shape of the arms  510  of the insert  500  has increasing thickness towards the free ends of the arms  510 , in particular a thickness or shape similar to that of the appendix  106 , thus providing an overall configuration of the appendix  106  with a tapered insert  500  of increasing thickness, as aforesaid. 
     In addition to all this, it must be said that the presence of the insert  500  of the invention, in particular of the portions or arms  510  thereof that extend in the clearance zones  107 ,  108 , determines a reduction in the thickness or mass of the covering or overmoulding material in the region where the suspended sections S 1 , S 2  and the ends  301 ,  302  of the electric wire are located: this will reduce the shrinkage of the covering and/or overmoulding material in said regions, resulting in less mechanical strain or stress on the electric wire, as well as no risk of immediate breakage or latent damage. 
     Finally, it must be pointed out that, according to a preferred version, the additional insert  500  also has some anchoring elements  530  acting upon the covering layer or body  400 , preferably in the form of lateral and/or frontal anchoring tabs  530 ; as will become apparent below, a wedge-like shape is most suited for the anchoring tabs  530 , even though it may be replaced by other shapes, e.g., a step-like shape or lowered-seat shape. 
     Preferably, the anchoring elements  530  comprise at least a part or face adapted to be covered by the covering or overmoulding material  400  and/or comprise thinner end portions  531 , particularly suited to be melted, at least partially, by the covering or overmoulding material  400  with which they come in contact, so as to obtain a welding and/or a chemical bond between at least a part of the body of the additional insert  500  and at least a part of the covering layer  400  of the device  1 . 
     The material of the covering layer  400  envelops at least a part of the additional insert  500 , possibly leaving uncovered some points thereof that may be useful for supporting and/or centering the assembly, particularly the semifinished product consisting of the reel  100  with the terminals  200 , the winding  300  and the inserts  500  assembled together, in the mould  600 . Preferably, the polymeric covering material  400  envelops a part of the terminals  200 , penetrating also into at least some seats and/or holes and/or apertures  207 ,  208 ,  209  for improved fixing. According to an inventive aspect, the covering or overmoulding material  400  is melted and/or chemically bonded with at least a part of the fastening and/or coupling means  502 ,  503 ,  504 ,  510 , in particular at least the ends  502 ′ ( 502 ′ a,    502 ′ b ) of the pins  502  ( 502   a,    502   b ) and/or  503 ′ of the rise  503  (see  FIGS. 13 and 17 ) inserted in the seats and/or apertures  207 ,  208 , for the purpose of improving the fixing of the insert  500  and/or terminals  200 . 
     Through an adequate selection of the materials of the insert  500  and covering  400 , of the dimensions of the parts, and of the temperatures and/or times of the overmoulding process, it is possible to cause the ends  502 ′ of the pins  502  and/or of the rise  503  to partially melt with the plastic material of the covering  400 , thereby fixing the insert  500 . 
     Said polymeric material of the covering  400  may also serve the purpose of forming, at least partly, the body or casing of an electric connector and/or coupling means for establishing a connection to another electric connector, such as the connector of an external electric wiring; the material of the covering layer  400  may possibly form at least a part of the body or casing of an electrovalve or an injector device. 
     In the light of these considerations, it is possible to explain in a simplified manner the method for industrial production of the electromagnetic device  1  according to the invention, by dividing it, for simplicity, into two main steps: a first step of assembling the various parts and winding the coil of wire  300  on the reel  100 , thereby obtaining a semifinished or intermediate product, whereon a second step of overmoulding the covering of polymeric material is then carried out. 
     In turn, these main steps can be divided into a number of sub steps. 
     For example, according to a preferred method for making or assembling the device  1  of the invention, a reel  100  provided with electric terminals  200  is prepared, which can be made, for example, by inserting the terminals  200  into the reel  100 , which is manufactured separately, or by overmoulding a polymeric material of the reel  100  on the terminals  200 . 
     In the next step of the process for making the device  1 , the electric wire  300  is wound on the reel  100 . 
     To this end, as previously explained, this step is carried out by first fastening an end ( 301  or  302 ) of the electric wire  300  to a lug or fitting ( 202   a  or  202   b ) of a respective terminal ( 200   a  or  200   b ), which provides a mechanical and electrical connection for the corresponding end ( 301  o  302 ) of the winding  300 . 
     After this, the electric wire  300  is wound on the body  101  of the reel  100  to form the main part of the electromagnetic coil, the second end of which ( 301  or  302 ) is fastened to the fitting lug ( 202   a,    202   b ) of the other terminal ( 200   a,    200   b ), just like the previous one. 
     It is worth mentioning that the order in which the ends  301 ,  302  are fastened can be reversed compared to  FIG. 19 , which should not be understood to set a specific limitation. 
     Furthermore, as already explained, the winding of the wire  300  and ends  301 ,  302  thereof is preferably accomplished by using a wire guide  401 ; however, the latter might not be used, or might be replaced with another equivalent tool. 
     Once this step is complete, a semifinished (or intermediate) product like the one shown in  FIGS. 7 and 8  is obtained, whereon the additional insert  500  is then applied. 
     The step of assembling the additional insert  500  depends on the configuration of the insert itself and/or on the way in which it is coupled to the reel  100  and/or the appendix  106  thereof and/or at least one of the electric terminals  200   a,    200   b.    
     In the case shown in  FIGS. 9 and 10 , for example, the insert  500  is juxtaposed to the lugs or fittings  202   a,    202   b  of the terminals  200   a,    200   b  so that the pins  502   a,    502   b  will enter the respective holes  207   a,    207   b  in the terminals  200   a,    200   b,  while the coupling means  504   a,    504   b  will engage with the respective seats  110  on the appendix  106 ; it should however be noted that said pins  502  and/or coupling means  504  may be present in a smaller number or be replaced with other fastening means. 
     In the case shown in  FIGS. 17, 18 , wherein the rise  503  is provided as a substitute for the pins  502 , when the insert  500  is juxtaposed to the terminals  200  the rise  503  will go into the corresponding seat  208 , defined between the opposite seats  208   a  and  208   b,  i.e., it will enter and/or fit in between the terminals  200   a  and  200   b.    
     Moreover, also the tenon portion  120  of the appendix  106  of the reel  100  and the mortise-shaped seat  513  of the insert  500  will be coupled together, thereby ensuring that the two parts are properly centered and/or joined. 
     As can be easily understood, the coupling between the additional insert  500  and the reel  100  is stable and accurate, so that they will remain assembled together at least during the next handling step and/or plastic/polymer overmoulding step for creating the insulating layer  400 . 
     This operation is effected by placing the semifinished product into a mould, as schematically shown in  FIGS. 25 and 26 . 
     As can be seen, the first one of these drawings depicts a mould  600 , with a part thereof removed to make the inside visible, which mould is intended for moulding the covering  400  over said semifinished product. 
     The mould  600  essentially comprises two first parts or half-moulds  601 ,  602 , respectively a lower one and an upper one in the drawings, and two sliding second parts  603 ,  604  adapted to move laterally, e.g., in opposite directions along said axis X of the device  1 : said second parts  603 ,  604  are mainly intended for forming inner parts or “undercut” parts of the device  1  and for closing the axial hole for positioning or sliding an external ferromagnetic yoke or core (not shown in the drawings) coupled to the device, while the half-moulds  601  and  602  define at least a part of the external profile of the insulating covering or casing  400 . 
     For simplicity, a lower half-mould  601  and an upper half-mould  602  can be considered as single pieces, wherein only the upper half-mould  602  is moved in order to close and open the mould  600 , while the second parts  603 ,  604  seal axially the moulding cavity  610  that houses the semifinished product. 
     The semifinished product is preferably so arranged that the ends  301 ,  302  of the wire and its suspended sections S 1 , S 2  are at the top (as shown in  FIG. 25 ), so that the fluidic mass spreading around the reel  100  will not damage them; at this stage, the insert  500  acts, as aforementioned, as a diaphragm protecting the ends  301 ,  302  of the wire and/or of its suspended sections S 1 , S 2  while the fluidic mass is spreading in the mould. 
     After the moulding material has been injected, at least some of the parts  601 ,  602 ,  603 ,  604  of the mould  600 , typically the half-moulds  601 , and second parts  603 ,  604  (or other components) are opened in order to extract the finished device  1 , possibly after a cooling step to allow the polymeric covering layer  400  to harden. 
     When the mould is opened, the axial components  603  and  604  of the mould  600  move along the longitudinal axis X of the coil, while the upper part  602  of the mould is moved away transversally to said axis X. 
     In accordance with a preferred embodiment of the process for making the device  1  according to the invention, the polymeric material of the insert  500  melts locally at some predetermined points to create an intimate junction with the covering  400  and become, de facto, one piece with it, resulting in clear advantages from a structural and mechanical viewpoint. 
     The anchoring wings or protrusions  530  promote this effect, while the mould  600  and its components  602 ,  604  are configured to allow the melted plastic material to penetrate around the terminals  200   a,    200   b,  on the side thereof opposite to the insert  500 . 
     Protection of the ends  301 ,  302  of the wire  300  is thus completed by an end covering  410  of the covering layer or body  400  of the device  1 , formed by the overmoulded plastic material. 
     The end covering  410  preferably comprises a convex, or anyway curved, portion  411  following the cylindrical profile of the covering  400 . 
     The end covering  410  is preferably configured in accordance with the presence of the additional element or insert  500 , so as to protect also the lugs or fittings  202   a,    202   b  for fastening the ends  301 ,  302  of the wire  300 . 
     It must however be pointed out that the invention has been described herein with particular reference to an electromagnetic device comprising at least one wound electric wire  300 , such as a solenoid or an electromagnet or an electromagnetic coil, which is preferably a part of an electromagnetic actuator of an electrovalve or an injector, in particular for apparatus or systems for injecting fuel into combustion or endothermal engines for vehicles. 
     Nevertheless, the same invention is also applicable to other types of devices, such as an antenna or an inductor for an electronic circuit or a winding of an electric actuator or motor or a solenoid and/or an electromagnet and/or an electromagnetic coil for different fields of application, such as the household appliance, medical, electronic or industrial industries, particularly as regards devices comprising electric wires having a diameter of less than 0.3 mm. 
     It is clear the devices described herein by way of example can be subjected to many variations by the man skilled in the art, without however departing from the scope of the invention. As aforementioned, further variants can be implemented by appropriately combining one or more of the features previously described with reference to different embodiments. 
     Furthermore, it must also be pointed out that the protection means, which in the examples taken into account herein essentially comprise the insert  500 , may however be more complex. 
     By way of example, a dual-insert solution may be conceived, i.e., a solution comprising a supplementary insert in addition to the insert  500  described herein, e.g., arranged on the opposite side relative to the lugs  202  and the terminals  200 . 
     Such a supplementary insert may also be different from the other insert, with specific coupling and/or engaging means for its connection to the electric terminals  200  and/or the appendix  106  of the reel and/or the insert  500 , which may even differ from those described herein. 
     In addition, the insert  500 , which in the case shown in the drawings is made as one piece, may be made as two or more pieces that can be connected to each other and/or to the electric terminals  200  and/or to the appendix  106  of the reel  100  by means of joints, couplings and the like, e.g., in accordance with the above-described teachings. In the case of two or more inserts  500  coupled together, there may be respective coupling and/or fitting elements, e.g., male-female and/or tenon-mortise pairs and/or seats and reliefs or hooks. 
     All of the features and variants described herein will still fall within the scope of the following claims.