FR2905527A1 - LOW VOLTAGE CONNECTION BLOCK OF AN IGNITION DEVICE, METHOD OF ASSEMBLING SUCH A DEVICE AND IGNITION DEVICE ASSEMBLED BY THE METHOD. - Google Patents

Abstract

The low-voltage connection block (LV) of an ignition device for an internal combustion engine, which is associated with a control and power computer of the ignition device, comprises connecting tongues (12, 22, 32 ) for connection to primary coils of ignition coils and interface tabs for connection to the computer for supplying voltage and activation signals to the connection tabs (12, 22, 32) by via the interface tabs, the connection tabs (12, 22, 32) extending substantially in the same plane. The invention is advantageously applied in the field of spark plug ignition of an internal combustion engine.

Description

The present invention relates to the field of lighting candles of a

  internal combustion engine of a motor vehicle. An ignition device makes it possible to supply electricity to the electrodes of the spark plugs of an engine, thereby generating electric arcs between these electrodes. Electric arcs can ignite a mixture of air and fuel contained in the engine cylinders. Such an ignition device, corresponding to a remote implantation, is described in patent application FR 2 646 552. With reference to FIG. 1, this device mainly comprises two ignition coils M1, M2, a low-voltage connector ( BT) 260, comprising connecting tongues 261, 262 and 263, and tubular insulation chimneys B1 to B4 incorporating metallic contact inserts 230 conducting a secondary current to apply a high voltage to the spark plugs. Each ignition coil M1, M2 comprises a central magnetic core 204, around which are coaxially disposed two bobbin carriers, or bobbins, 203, 205, of plastic, respectively supporting a primary winding 202 and a secondary winding 206. A winding 202, 206 comprises a wire, traditionally made of copper, wound around the winding 203, 205 corresponding to form turns. A primary winding 202 generally has about 100 turns, while a secondary winding 206 generally has about ten thousand turns.

  The metal inserts 230 are housed in wells 264 attached to the upper part of the winding 205 supporting the secondary winding 206 of each ignition coil M1, M2, an electrical contact being established between the inserts 230 and the secondary winding 206.

  The low voltage connector 260 provides the connection of a motor control computer to the coils M1, M2, a wiring harness connecting the computer to the connector 260. The function of the computer is to supply each primary winding 202 of each coil M1, M2 with a supply voltage and an activation signal, or control, acting as a switch to let or not a current in the primary winding 202. The activation signal is generated by the computer. The connector 260 has three connection tabs 261, 262, 263 connected to the primary windings 202 of the coils M1, M2.

A first tab 263 serves to supply the primary windings 202 with a DC voltage of between 12V and 14V. A second tab 261 and a third tab 262 carry the activation signal to the primary winding 202 of the first coil M1 and the second coil M2, respectively. When the primary winding 202 of a coil is activated, the secondary winding 206 of the coil generates a very high voltage, of the order of 30kV, at the terminals of the metal inserts 230 which are connected to it, this voltage being transmitted to the electrodes of the spark plugs by a bundle of cables connecting the metal inserts 230 to these electrodes.

The ignition device described above is integrated in a plastic housing 211. A synthetic resin, cast inside the housing, secures and electrically isolates the various components of the ignition device. The low voltage connector and the high voltage tubular chimneys B1 to B4, including the high voltage inserts 230, protrude from the housing 211. The assembly of the ignition device as described above is time-consuming because it requires numerous and complex assembly steps.

To facilitate this assembly, transformation modules are assembled beforehand, each module comprising the central magnetic core 204, around which are coaxially arranged the two windings 203, 205 respectively carrying the primary winding 202 and the secondary winding 206.

During the final assembly of the ignition device, the metal inserts 230 are overmolded in the tubular chimneys B1 to B4, these are then screwed, with the lower threaded portion of the inserts 230, into the wells 264 of each module. of transformation. Each high-voltage chimney is screwed separately. Thus, for an ignition device, such as that of Figure 1, comprising two coils M1, M2 for supplying four spark plugs, four screwing steps are necessary to have all the high voltage chimneys. It is then necessary to connect the primary windings 202 with the tabs 261, 262, 263 of the low voltage connector 260, i.e. with the tab 263 for supplying a DC voltage and the tabs 261 and 262. for providing an activation signal for the ignition coils M1, M2. The connection of the tabs 261, 262, 263 is a delicate step, since the tabs must reach the primary windings 202, arranged within the secondary windings 206 in each transformation module. The end of each wire forming the primary winding 202 is then welded into a wallet of the tongue, to ensure electrical conduction.

All the assembled elements are then placed in the housing before the insulation resin is poured. Ultimately, the method of mounting an ignition device comprises all of the following steps: 1. overmolding the metal inserts 230 in the tubular chimneys B1 to B4, to form the high voltage chimneys; 2. screwing the high voltage chimneys (through the threaded portion of the metal inserts) into the wells 264 of the assembled transformation module; 3. the overmolding of the connecting tabs 261, 262 and 263 in the output connector of the ignition coil to form the connector 260; 4. the soldering of the connection tabs 261, 262 and 263 to the primary windings 202 of the coils M1. and M2; 5. inserting the assembly into a housing 211 and 6. casting an insulating resin into the housing 211; In addition, the low voltage connector 260 is generally located on an axis perpendicular to the axes of the coils; the coils and connectors being aligned. It results from the position of the low voltage connector 260, disposed at one end of the housing 111, that it is closer to one coil than the other, in this case the coil M2. The connection of the tabs 261, 262, 263 of the low voltage connector 260 to the furthest coil, here the coil M1, is delicate, since the tabs 261, 262, 263 conducting a low voltage extend near elements metal of the coil M2 conducting a high voltage, such as the secondary winding 206, thereby causing a risk of routing of the voltage between these elements. The invention aims to overcome at least some of these defects and to provide a simpler, safer and faster ignition device assembly. To this end, the invention relates to a low voltage connection block (LV) of an ignition device for an internal combustion engine, which is associated with a control unit for power supply and control of the ignition device, said block comprising connecting tabs for connecting to primary windings of ignition coils, and interface tabs for connecting to the computer for supplying voltage and activation signals to the connection tabs; via the interface tabs, and wherein the connecting tabs extend substantially in the same plane. This arrangement is particularly advantageous when the coils are arranged with their axes parallel to each other, the plane of the tongues of the connection block being advantageously orthogonal to these axes. In this case, it is preferable that the connecting tabs extend substantially parallel to each other. This arrangement of the tabs on the primary windings is simple and promotes rapid assembly. Advantageously, metal links, connecting the connection tongues 20 to the interface tongues, comprise a circular curvilinear portion arranged along their length and arranged to better further avoid the path of the voltage between the high voltage and the low voltage. Preferably, the connecting tongues comprise a fixing means 25 disposed at their free end, advantageously a notching notch. Thus, it is no longer necessary to weld the tongues during assembly, which reduces the assembly time of the ignition device.

Advantageously, a mechanical fastening means makes it possible, by thermoplastic molding, to hold the tabs integral with each other, and also to improve the electrical insulation of said tabs with respect to the high voltage. The tabs are mechanically secured to facilitate their insertion into the device and be arranged in one and the same operation. The invention also relates to a low voltage connection block with high voltage outputs comprising the low voltage connection block of the invention, metal inserts, high voltage chimneys and a thermoplastic link, block in which the metal inserts, connecting to a secondary winding of an ignition coil, are overmolded in the high voltage chimneys (HT), HT chimneys being connected to the low voltage connection block by the thermoplastic link. Overmoulding of the low-voltage connection block with the high-voltage outputs makes assembly easier since it is no longer necessary to screw the HT chimneys one by one.

The invention also relates to an ignition device comprising ignition coils, a low voltage connection block with high voltage outputs and a housing, and a method of assembling such a device in which the With the ignition coil connection block, the ignition coils with the block in the housing are arranged and a synthetic electrical insulation resin is poured into the housing. The mounting of an ignition device according to the invention comprises a lesser number of steps, so it is simpler to implement.

Preferably, the connection tabs of the low-voltage connection block with high-voltage outputs are connected in centering modules, attached to a primary winding of an ignition coil, and the base of the metal inserts is connected by scratching in a housing. eyelet of a metal part 25 fitted in a secondary winding under guide wells located at the ends of said secondary winding of an ignition coil. The invention will be better understood from the following description with reference to the accompanying drawing in which Figure 1 shows an ignition device for an internal combustion engine of the prior art, exploded; FIG. 2 represents a perspective view of the low voltage connector according to the invention; FIG. 3 is a perspective view of the low voltage connection block with high voltage outputs according to the invention; Figure 4 shows a top view of the block of Figure 3; Figure 5 shows a side sectional view of the block of Figure 3; Figure 6 is a diagrammatic exploded perspective view of an ignition device incorporating the invention; FIG. 7 represents a sectional view of an assembled ignition device according to the invention and FIG. 8 represents a perspective view of one of the ignition coils of the device of FIG. 7. Referring to FIG. 2, a low voltage connection block 1, in this case a simple connector, comprises interface tongues 11, 21, 31 and connecting tongues 12, 22, 23, 32. These tongues are grouped into three groups. connecting tongues 10, 20, 30, the second group 20 having in fact two connecting tongues 22, 23. The interface tongues 11, 21, 31 comprise rectangular metal blades, flattened, here of the same length, in a same plane, parallel to each other, extending rectilinearly along an axis X and aligned along an axis Y. The connecting tongues 12, 22, 23, 32 comprise metal plates, rectangular, in the same plane, flattened, parallel between they, extending rectilinearly selo n an axis Z orthogonal to the X and Y axes and aligned along the Y axis, comprising at their free end a fastening means, in this case a notching notch, referenced, for example, 320 on the tongue 32. The interface tongues 11, 31 are electrically connected to the connection tongues, respectively 12, 32, by metal links respectively 13, 33. With reference to FIGS. 1, 2 and 3, the links 13, 33 are in the form of a rectangular flattened blade. extending generally along the axis Y, comprising a circular curvilinear portion lying in the plane (X, Y) and extending along the axis X. This circular curvilinear portion is arranged so as to remain at a constant distance from the elements high voltage of an ignition device, in particular high voltage outputs. The assembly consisting of the connecting tab 12, the metal link 13 and the interface tab 11 forms a first metal group 10 of the connector 1. With respect to the plane formed by the orthogonal axes X and Z, the group 10 and the second metal group 30 of the connector 1 are symmetrical. The group 30 is composed of the connection tongue 32, the metal link 33 and the interface tongue 31. The two groups 10, 30 are aligned along the Y axis, the group 20 being situated between the groups 10 and 30 The group 20 comprises the interface tongue 21 connected by a flat metal link 24 to the connection tongues 22, 23. The group 20 is in the form of a fork with two teeth bent at 90 degrees, in the clockwise along the axis oriented X, at the base of the interface tongue 21. The interface tongue 21 forms the handle 5 of the fork and the connecting tongues 22, 23 form respectively the two teeth of the fork. With reference to FIGS. 3, 4 and 5, the low voltage connector 1 is overmolded with plastics material. This plastic overmolding 70 holds the three metal groups 10, 20, 30 integral and projects the free end of the tongues 11, 12, 21, 22, 23, 31, 32. The interface tongues 11, 21, 31 are protected by a plastic casing 67 integral with the overmolding 70. In the present embodiment, a fixing means, here locking lugs 671, 672, attached to the outer casing 67, are arranged to cooperate with one end. a bundle of cables that carries activation and control signals delivered by a computer. With reference to FIG. 6, the low-voltage connection block 1 connects to ignition coils 100, 200 comprising a central magnetic core 104 around which coaxial two coils are held, or coils 103, 105 plastic, respectively supporting a primary winding 102 and a secondary winding 106. A winding, primary or secondary, consists of a wire, traditionally copper, wound around the winding 103, 105 corresponding to form turns.

The function of the computer is to supply each primary winding 102 of each coil 100, 200 with a supply voltage and an activation signal acting as a switch for passing or not a current in the primary winding. 102. The tongues 22, 23 make it possible to feed the primary windings 102 with a DC voltage of between 12V and 14V. The tongue 12 and the tongue 32 carry the activation signal to the primary windings 102 of the coils 100, 200. The connection tongues 12, 22, 23, 32 are connected by means of their scratching notch 320 to each end of the coils. wires of primary windings 102.

The bobbin 103 is of generally cylindrical shape comprising four flattened faces, one of whose faces comprises a plastic support 81; this face will be designated later connection face. The plastic support 81 extends along the axis of the coil 100, 200 in the extension of said connection face. The support 81 comprises two grooves and two centering modules 82, each end of the wire of the primary winding 102 is guided in a groove and is held taut in notches of the centering modules 82. The centering notches facilitate the connection of the connection tongues 12, 22, 23, 32, it is sufficient to scratch the tensioned wire to establish the electrical connection and it is no longer necessary to weld the tongues at the ends of the wire of the primary winding 102. The centering modules 82 are equipped with a horizontal support between the two notches on which rests the end of the wire of the primary winding 102. This 10 support makes it possible not to drive the wire inside the notches during the scratching of the tongues 12, 22 , 23, 32. With reference to FIGS. 3, 4, 5 and 6, the low voltage (LV) connection block 1 is associated with a high voltage output block (HT) to form a low voltage connection block with outputs high voltage (B T / HT) 2. The BT / HT 2 unit comprises the BT connector 1 described above, HT stacks 41, 42, 43, 44, comprising metal inserts 51, 52, 53, 54, and a thermoplastic connection 65 connecting the HT chimneys with plastic overmolding 70 of the low voltage connector 1.

An HT stack 41, 42, 43, 44 is here in the form of a hollow cone whose base diameter is greater than the diameter of the top. As shown in FIG. 5, an insert 51, 52, 53, 54 is molded inside the chimneys 41, 42, 43, 44. The base of the insert projects out of the base of the chimney so that The thermoplastic link 65 connects the low voltage connector 1 with the HT chimneys 41, 42, 43, 44. The link 65 extends rectilinearly from the envelope. 67, along the X axis, to divide into four branches and connect respectively to the base of each HT stack 41, 42, 43, 44, these being arranged in a square in the plane (X, Y). Plastic feet 61, 62, 63, 64, as shown in FIG. 4, are attached to the base of the HT chimneys 41, 42, 43, 44 and form an excrescence at the base to stiffen the connection. between link 65 and HT chimneys.

The assembly of such an ignition device is then facilitated. The low voltage connection block with high voltage outputs 2, comprising the connection and interface tongues 11, 12, 21, 22, 23, 31, 32, the metal inserts HT 51, 2905527 9 52, 53, 54, the high-voltage chimneys 41, 42, 43, 44, the plastic over-molding 70 and the thermoplastic link 65, is made in a single overmolding operation. To assemble the ignition device, the block 2 BT / HT is connected electrically to the coils 100, 200. Then, the BT / HT block 2 connected with the coils 100, 200 is placed in a rigid plastic case 107 and sinks in the housing 107 a synthetic resin of electrical insulation. Block 2 electrically connects to ignition coils 100, 200 by positioning itself on the connecting face of said coils 103. As shown in FIGS. 7 and 8, connection tongues 12, 22, 23, 32 connect to each other. the centering notches and the metal inserts 51, 52, 53, 54 overmolded in the HT chimneys, are introduced into metal parts 85 equipped with serrated eyelets 87, inserted under the wells 83 of the windings 105 supporting the secondary winding 106, said piece 85 comprising a small protuberance 86 around which the end of the wire of the secondary winding 106 is wound and then welded. The wells 83 are arranged to correspond with the base of the metal inserts 51, 52, 53, 54, and guide these inserts in the metal part 85 of connection with the secondary winding 106. The inserts are thus electrically connected to the secondary winding 106. The connection with the inserts 51, 52, 53, 54 is made by fitting, the inserts being scratched at their lower part in the serrated eyelets 87 of the metal parts 85. Finally, a device for the assembly has been assembled. ignition comprising the connection block 2, the housing 7 and the ignition coils 100, 200, in which the inserts 51-54 are connected to the metal parts 85 which each comprise an eyelet 87. When the computer, connected by the cable bundle at the LV / HT block 2, supplies and delivers an activation signal to the primary windings 102, a high voltage is created by induction at the secondary winding 106, this high voltage is transmitted by the metal piece 85 located at the base of the wells 83 to the metal inserts 51, 52, 53, 54 of the BT / HT block 2. A wiring harness is connected to the top of each stack HT 41, 42, 43 44 to make electrical contact with the inserts 51, 52, 53, 54 and conduct the high voltage 35 to the spark plugs. The metal links 13, 33 advantageously comprise a circular curvilinear portion to maintain a constant distance with the chimneys HT 41, 42, 43, 44. The chimneys may be in various forms, such as square-based chimneys. To maintain a constant distance between the high voltage elements and the low voltage elements, the link 13, 33 then comprises a portion of shape complementary to the shape of HT chimneys. 5

Claims (14)

claims   1. Low voltage connection block (LV) (1) of an ignition device for an internal combustion engine, which is associated with a control computer of power and control of the ignition device, said block comprising connecting tabs (12, 22, 23, 32), for connecting to primary windings (102) of ignition coils (100, 200), and interface tabs (11, 21, 31) for connecting to the computer for supplying a voltage and activation signals to the connection tongues (12, 22, 23, 32) via the interface tongues (11, 21, 31), characterized in that the tongues connection (12, 22, 23, 32) extend substantially in the same plane.   2. LV connection block (1) according to claim 1, wherein the connecting tongues (12, 22, 23, 32) extend substantially in the same plane, plane intended to be orthogonal to the axes of the ignition coils. (100, 200), the windings of which the tongues are intended to connect.   3. LV connection block (1) according to one of claims 1 to 2, wherein the connecting tongues (12, 22, 23, 32) are parallel to each other.   4. LV connection block (1) according to one of claims 1 to 3, wherein metal links (13, 33), connecting the connection tabs (12, 32) to the interface tabs (11, 31). , comprise a circular curvilinear portion along their length and arranged to prevent the path of the voltage between the high voltage and the low voltage.   5. LV connection block (1) according to one of claims 1 to 4, wherein the connecting tongues (12, 22, 23, 32) comprise a fixing means disposed at the free end of the connecting tongues ( 12, 22, 23, 32).   6. LV connection block (1) according to one of claims 1 to 5, wherein the connecting tongues (12, 22, 23, 32) comprise a notching notch (320) disposed at the free end of the tongues connection (12, 22, 23, 32). 2905527 12   7. LV connection block (1) according to one of claims 1 to 6, wherein a mechanical securing means keeps the connecting tongues (12, 22, 23, 32) integral with each other. 5   8. Low voltage connection block with high voltage outputs (2) comprising the LV connection block (1) according to one of claims 1 to 7, metal inserts (51, 52, 53, 54), high voltage chimneys (HT) (41,42,43,44) and a thermoplastic link (65) block in which the metal inserts (51,52,53,54) connect to a secondary winding (106) of a coil ignition (100, 200) and are overmolded in the HT chimneys (41, 42, 43, 44), HT chimneys being connected to the low voltage connection block (1) by the thermoplastic link (65).   9. Low voltage connection block with high voltage outputs (2) according to claim 8, wherein the HT chimneys (41, 42, 43, 44) comprise feet (61, 62, 63, 64) molded to the base of the HT chimneys to stiffen the connection with the thermoplastic link (65).   10. Low voltage connection block with high voltage outputs (2) according to one of claims 8 to 9, wherein the metal links (13, 33), connecting the connection tongues (12, 32) to the tongues of interface (11, 31), have a portion along their length arranged to be maintained at a constant distance from HT chimneys (41, 42, 43, 44). 25   Ignition device comprising the low voltage connection block with high voltage outputs (2) according to one of claims 8 to 10 and the ignition coils (100, 200) to which the connection tabs are connected. said block, and a housing (107) for receiving the device, wherein the metal inserts (51, 52, 53, 54) of said connection block (2) are connected to metal parts (85) under guide wells (83) ignition coils (100, 200).   An ignition device according to claim 11, wherein the metal parts comprise an eyelet (87) arranged to receive the metal inserts (51, 52, 53, 54).   13. A method of assembling an ignition device according to one of claims 11 to 12, wherein the low voltage connection block 2905527 13 with high voltage outputs (2) is connected to the ignition coils (100, 200), the assembly of the block (2) and the ignition coils (100, 200) is arranged in the housing (107) and a synthetic electrical insulation resin is poured into the housing (107). 5   14. A method of assembling an ignition device according to claim 13, wherein the connecting tabs (12, 22, 23, 32) of the low voltage connection block with high voltage outputs (2) are connected in centering modules (82) attached to a primary winding (103) of an ignition coil (100, 200) and connecting the base of the inserts (51, 52, 53, 54) in said metal parts (85) .