Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
  • H01F38/12—Ignition, e.g. for IC engines

Definitions

• the present invention relates to a magnetic core closed ignition coil and permanent magnet. It finds a general application in electrical engineering and more particularly in internal combustion engine engines with spark ignition, in which the combustion of the gaseous mixture in the cylinders is caused by a spark generated between the electrodes of a spark plug ordered by an ignition coil.
• a closed permanent magnet magnetic core (or circuit) ignition coil comprises a first U-shaped magnetic core element and a second bar-shaped magnetic core element around which are wound a primary winding and a secondary winding. forming with the second core member a "coil module".
• the coil module is mounted transversely between the two branches of the U of the first core element and the assembly is inserted into a housing of protection.
• the inside of the protective case can then be filled with resin to electrically isolate the various elements of the ignition coil and form a sealed block suitable for use in a motor vehicle.
• the end surfaces of the second bar-shaped core member are in contact with inner end surfaces of the legs of the first U-shaped core member.
• the permanent magnet generally forms one of ends of the second bar-shaped core member; it makes it possible to increase the power of the ignition coil and / or to reduce its bulk.
• the inner end surface of a U-limb of the first core member of WO 94/06134 has a tapered shape, as does the complementary end surface of the second core member. bar, to define a mounting ramp for the inclined surfaces in contact with each other.
• Deformable protuberances protruding from the other end surface of the second bar-shaped core element (or that of the permanent magnet), are intended to provide, by their crushing, a margin of error for the clamping between the two magnetic core elements.
• the air gap is not completely reduced to zero, which leaves air gaps between the facing surfaces. These air spaces can be the seat of a resin infiltration during the resin of the housing, which reduces the efficiency of the magnetic core and therefore the ignition coil.
• the present invention aims to overcome these disadvantages.
• the invention relates to an ignition coil comprising a protective housing, a magnetic core closed with a permanent magnet, the magnetic core comprising a first substantially U-shaped core element housed in the protective housing and a second substantially bar-shaped core member, the first core member having at least two contact surfaces with the second core member, the coil having at least one primary winding and a secondary winding around the second core member and forming with it a coil module, characterized in that the contact surfaces of the first core member are both beveled to allow mounting of the coil module in the housing.
• the introduction of the coil module in the protective housing is simpler, which facilitates the industrialization of the process of manufacturing the ignition coil.
• this may allow a "blind" mounting step of the coil module in the protective housing, the first U-shaped core element having previously been mounted in the housing.
• the beveled contact surfaces can serve as a guide ramp when placing the coil module in the protective housing, the second core element can for example be moved and guided along one of these surfaces, the presence of a bevel on the other side ensuring sufficient clearance for a gradual movement while allowing to catch any errors, without it being necessary to provide other means securing the establishment such as for example the stops or protuberances of the prior art; the core elements are thus simpler and less expensive.
• the presence of two bevels also allows the support, intentionally or by mistake, on one surface instead of the other.
• the second core element having at least two contact surfaces with the contact surfaces of the first core element, these contact surfaces have a beveled shape complementary to the beveled shape of the contact surfaces of the first element. of core.
• Complementary form means a form allowing contact plan of the surfaces considered. The gap between the surfaces facing each other is thus reduced to a minimum and may advantageously be zero.
• At least one contact surface of the second core element is formed by a surface of the permanent magnet.
• the second core element is in the form of a T-shaped bar having a main branch extending along an axis and a transverse branch inclined with respect to the axis of the main branch. , the transverse branch supporting the permanent magnet.
• the first core element comprising two branches corresponding to the branches of the U of which it has the shape, its contact surfaces are end surfaces of said branches.
• each branch having an inner side and an outer side, the contact surfaces of the first core member are located on the inner side of the branches.
• each branch extending generally along an axis, each contact surface is inclined at an acute angle with respect to the axis of the branch considered.
• the protective casing is overmoulded around the first core element.
• Such a housing makes it easy to respect precise mounting dimensions.
• the contact surfaces of the first core element have different lengths. This makes it possible to favor contact with one of these surfaces, in particular if the permanent magnet forms one end of the second core element, the contact surface with the permanent magnet then preferably being the largest to favor the contact. with the magnet.
• an insert is connected to the secondary winding and is arranged to make contact with an electrical conductor housed in the protective housing and connected to a high voltage insert. The invention, which guarantees a good implementation of the coil module on the first core element, thus guarantees the proper placement of the secondary winding in the protective housing and therefore the good contact of the insert with the electrical conductor.
• the invention further relates to a method of manufacturing an ignition coil having a protective housing, a magnetic core closed with a permanent magnet, the magnetic core having a first substantially U-shaped core member housed in the housing of protection and a second substantially rod-shaped core member, the first core member having at least two beveled contact surfaces with the second core member, the coil having at least one primary winding and a secondary winding around the second core member. kernel, the method comprising the following steps:
• the first core element is housed in the protective casing
• the coil module is mounted in the protective housing by contacting the second core element with the contact surfaces of the first core element.
• the first core element is housed in the over-molded protective casing of the protective casing around the first core element. Such a step is simple to implement and perfectly encapsulates the first core element in the housing.
• the second core element having at least two contact surfaces with the contact surfaces of the first core element and having a beveled shape complementary to the beveled shape of the contact surfaces of the first core element, mounting the coil module in the protective case by moving a contact surface of the second core member along a contact surface of the first core member.
• at least one end surface of the second core element being formed by a surface of the permanent magnet, the the contact surface of the second core member displaced along a contact surface of the first core member is that of the permanent magnet.
• contact is made between an insert connected to the secondary winding and an electrical conductor housed in the protective housing and connected to a high voltage insert.
• FIG. 1 shows a wired perspective view of a protective housing overmolded around a first U-shaped core element according to the invention
• FIG. 2 represents an exploded view of the elements of a coil module according to the invention
• FIG. 3 shows the coil module of Figure 2 mounted in the protective housing of Figure 1, in wire profile view;
• FIG. 4 shows a perspective view of the first U-shaped core element of FIG. 1;
• FIG. 5 is a perspective view of the second bar-shaped core element of the coil module of FIG. 2;
• FIG. 6 represents a perspective view of the second core element of FIG. 5 mounted between the two branches of the U of the first core element of FIG. 4.
• An ignition coil 1 comprises a magnetic core (or circuit) closed with a permanent magnet 21, the magnetic core comprising a first substantially U-shaped core element 4, housed in a protective casing 2, and a second substantially rod-shaped core element 20 around which are wound a primary winding 23 and a secondary winding 36 in which respectively an electrical input current of the coil and an electrical output current of the coil are circulated, respectively classic.
• the second core element 20 and the primary 23 and secondary 36 windings form a coil module 3.
• the coil 1, shown in FIG. Figure 3 is formed by the assembly of the coil module 3 (shown in Figure 2) in the housing 2 in which is housed the first core element 4 (shown in Figure 1). With reference to FIG.
• the first U-shaped core element 4 is formed, in this case, of a stack of sheets held together and is named, in the following description, first core element 4
• This core element 4 comprises a base 42 and two branches 6a, 6b corresponding to the base and the branches of the U of which it has the shape.
• the first core element 4 comprises two surfaces 5a, 5b of contact with the second core element 20; these contact surfaces 5a, 5b are planar and bevelled to allow mounting of the coil module 3 (including the second core element 20) in the protective housing 2 (in which is mounted the first core element 4).
• the second core element 20 also has two surfaces 21a, 31b (in this case end) contact with the contact surfaces 5a, 5b of the first core element 4.
• a surface 21a is formed by a surface of the permanent magnet 21, the latter being fixed on a surface 31a of the second core member 20, as described in more detail below.
• the contact surfaces 21a, 31b of the second core member 20 are planar and beveled, each of complementary shape to the shape of the contact surface 5a, 5b of the first core member 4 with which it is intended to come into contact; this complementarity of shapes allows plane contact between the surfaces (5a, 21a), (5b, 31b) of each pair of contact surfaces (the shapes being of course arranged to allow contact at each of the branches of the U).
• the protective housing 2 is substantially parallelepipedal in shape and has an inner surface shaped to match the outer shape of the first core member 4, of which only the inner surfaces are visible in the housing 2 when it is housed therein. More specifically, the protective casing 2 is in this case overmolded around the first core element 4. In this case, the protective casing 2 has an opening 7 on the upper side, through which the coil module 3 can be mounted. in the case 2; it also comprises a bottom wall 8 and solid side walls, shaped to fit the outer surfaces of the first core member 4 and allow the assembly of the coil module 3.
• the shape of the housing 2 is accessible to the man of the profession and it is not necessary to further detail its description.
• Fastening means may be provided on the housing 2, to cooperate with corresponding means of the vehicle (not shown) to allow the attachment of the housing 2 to the vehicle, in a conventional manner.
• a conductive element 15 such as a resistor is disposed inside the first cylindrical housing 13 and is electrically connected to a part conventionally called a high-voltage insert 16, housed in the second cylindrical housing 14 and intended to be connected to a spark plug. ignition, not shown, to transmit the voltage necessary for its ignition.
• the coil module 3 comprises the second core element 20, which supports the permanent magnet 21, the primary winding 23 and the secondary winding 36, in a known manner.
• the primary 23 and secondary windings 36 are each wound around a plastic carcass or bobbin 22, 35, respectively, in a known manner that it is not necessary to describe in detail.
• the casing 22 of the primary winding 23 is fitted around the second core element 20 and the casing 35 of the secondary winding 36 is fitted around the primary winding 23, in a known manner.
• the second core element 20 is for example formed of a stack of sheets held together, similarly to the first core element 4.
• the second core element 20 is in the form of a T-shaped bar comprising a main branch 24 extending generally along the X axis and an inclined transverse branch 25, the permanent magnet 21 being in this case fixed to a flat end surface 31a of the transverse branch 25.
• the second core member 20 may be in the form, not of a T but of an I, arranged to be mounted between the two branches 6a, 6b of the first core element 4.
• the bobbin 35 of the secondary winding 36 is in the form of a hollow body for housing the primary winding 23 and its winding 22. At its end opposite to that corresponding to the side of the permanent magnet 21, the bobbin 35 comprises, in the upper part, a tongue 38 projecting generally parallel to the axis X. Two notches 40 are formed under the tongue 38, on either side of the bobbin 35; they are arranged to receive tabs of a T-shaped electrical contact element 41, conventionally called insert 41 or secondary insert 41 and whose function is to establish an electrical contact between the secondary winding 36 and the conductive element 15 connected to the high voltage insert 16, in known manner.
• the tongue 38 provides protection and positioning of the secondary insert 41. In the mounting position of the ignition coil 1 (as illustrated in FIG.
• the relative positions of the core elements 4, 20 guarantee the relative position. of the secondary insert 41 (integral with the coil module 3 and therefore the first core element 20) with respect to the conductive element 15 (integral with the protective housing 2).
• the two branches 6a, 6b of the first core element 4 are asymmetrical, the bevelled surface 5a intended to be in contact with the surface 21a of the magnet 21 being of larger dimension, in the plane of cut formed by the X and Y directions, than the other bevelled surface 5b.
• This conformation is chosen to confer particularly on the surface 5a of contact with the magnet 21 a guide ramp function of the second core element 20 via the magnet 21; thus, when mounting the coil module 3 in the protective housing 2, the surface 21a of the magnet 21 is moved along the corresponding contact surface 5a of the first core element 4 until the opposite surfaces 5b, 31b of the first and second core members 4, 20 come into contact with each other.
• the dimension of the branch 6a with the largest bevelled surface 5a is larger, in the direction of the Y direction, than the dimension of the other branch 6b, which ensures that the first contact established with the second core element 20 is preferably on this larger branch 6a.
• the contact surfaces 5a, 5b of the first core element 4 are provided on its inner side. They each extend from one end 43a, 43b of a branch 6a, 6b, respectively, the corresponding thickness of the branch 6a, 6b in the X and Y plane increasing from this end to the base 42 of the core element 4, as seen in Figure 4.
• the contact surfaces 5a, 5b are inclined at an acute angle a, a ', respectively, with respect to the direction Y, the angles a, a 'being in this case identical value, these angles being opposite trigonometrically.
• the two branches 6a, 6b of the first core element 4 may be symmetrical; other arrangements of the shape of the branches 6a, 6b are also conceivable, the essential being that each branch 6a, 6b of the first element of core 4 have a bevelled surface 5a, 6b to allow the displacement of the second core member 20 when it is put in place of the coil module 3 in the protective housing 2.
• the end surfaces 21a , 31b of the second core member 20 are inclined at an acute angle ⁇ , ⁇ ', respectively, relative to a direction P perpendicular to the direction of the main branch 24 of the T whose second core member 20 is shaped.
• angles ⁇ , ⁇ ' are in this case respectively equal to the angles a, a' that are the contact surfaces 5a, 5b of the first core member 4 with the direction Y.
• the second core member 20 is arranged to be mounted in the housing 2 so that the main direction of its main bar 24 extend parallel to the X direction of the base of the U whose first core element 4 has the shape, that is to say that the direction P perpendicular to its main branch 24 then extends parallel to the Y direction of the branches of the U.
• the contact surfaces (5a, 5b), (21a, 31b) are complementary and arranged to come into plane contact, ensuring a zero gap between the first core member 4 and the second core member 20.
• This relative position of the core members 4, 20 is shown in Fig. 6 (only the core members 4, 20 being shown in this figure without the primary and secondary windings 23 36 or the protection box 2).
• the protective casing 2 is overmoulded around the first core element 4. Furthermore, the coil module 3 has been previously mounted, that is to say the second core element 20 has been inserted in the winding 22 of the primary winding 23 which has itself been inserted into the winding 35 of the secondary winding 36.
• the second core member 20 is brought into contact and then displaced by the surface 21a of the permanent magnet 21 along the beveled contact surface 5a of the first core member 20; this displacement is effected until the opposite contact surface 31b of the second core member 20 comes into contact with the other contact surface 5b of the first core element 4.
• this contacting of the opposite contact surfaces 5b, 31b is accompanied by a sound snap which attests the good positioning of the second core element 20 with respect to the first core element 4, that is to say the good positioning of the coil module 3 with respect to the housing 2.
• the magnetic core of the ignition coil 1, formed by the first and the second core elements 4, 20 is thus closed.
• the permanent magnet 21 is fixed at another location of the magnetic core. Wherever the magnet 21 is fixed, the displacement of the second core member 20 with respect to the first core member 4 may or may not be along a surface of the magnet 21; it is preferably along a surface of the magnet 21 insofar as the magnet 21 tends to be attracted by the core element 20, 4 on which it is not fixed.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Ignition Installations For Internal Combustion Engines (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2009
  • 2009-10-15 FR FR0957235A patent/FR2951579B1/fr not_active Expired - Fee Related
• 2010
  • 2010-09-22 WO PCT/FR2010/051988 patent/WO2011045498A1/fr active Application Filing
  • 2010-09-22 CN CN2010800570946A patent/CN102656647A/zh active Pending
  • 2010-09-22 JP JP2012533669A patent/JP2013507783A/ja active Pending
  • 2010-09-22 BR BR112012008856-4A patent/BR112012008856A2/pt not_active Application Discontinuation
  • 2010-09-22 EP EP10773121A patent/EP2489051A1/de not_active Withdrawn

Non-Patent Citations (1)

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