JPH07130559A - Ignition coil for motorcar - Google Patents

Abstract

PURPOSE:To provide a motorcar ignition coil with which potential can be distrib uted uniformly, and the dielectric breakdown generated on the path, where a crossover wire is formed, can be prevented. CONSTITUTION:A secondary winding bobbin 5 is provided with six grooves which are divided by partitioning walls 5a to 5e, and secondary windings 4a to 4f are split-wound thereon. These grooves have the same rectangule-shaped cross-section and are arranged in a row in the axial direction (horizontal direction as shown in the diagram). The secondary windings 4a to 4f are constituted in such a manner that their number of winding stages decreases from the low potential side of in-groove potential distribution toward the high potential side when excited as in 4f>4e>4d>4c>4b>4a. Also, partition walls 5a to 5e are constituted in such a manner that their thickness increases as 5e<5d<5c< 5b<5a from low potential side to high potential side. On the partition walls 5a to 5e, crossover paths, where crossover wires 53a to 53e which are used to connect the secondary windings to be wound on both sides of the grooves respectively, are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ignition coil,
In particular, the present invention relates to an automobile ignition coil in which a primary coil and a secondary coil are arranged around the same iron core.

[0002]

2. Description of the Related Art Generally, an ignition coil for an automobile has a primary winding arranged inside and a secondary winding dividedly wound around the same iron core in accordance with a demand for miniaturization. There is. At this time, like the general transformer, the potential of the secondary winding is almost the ground potential at the beginning of winding,
As the number of turns increases, the potential becomes higher, and at the end of the turn, the potential becomes as high as 30 kV, and insulation failure is likely to occur due to contact and proximity of the secondary windings. The following have been proposed as known techniques for preventing this and reducing the size without lowering the insulation performance.

Japanese Patent Publication No. 60-500152 discloses this known technique, in which the inner one is arranged around the same iron core.
Regarding the secondary winding and the secondary winding of the outer divided winding, the insulation interval between the primary winding and the secondary winding is increased with an increase in the potential in the bobbin groove, so that the potential distribution is made uniform and insulation is performed. It ensures performance.

[0004] Japanese Laid-Open Patent Publication No. 1-274410 discloses a known technique in which the inner core 1 is arranged around the same iron core.
Regarding the secondary winding and the secondary split secondary winding, the axial length of the split groove of the bobbin of the secondary coil is increased from the winding start portion to the winding end portion according to the potential distribution when the coil is energized. By making it small, the potential distribution is made uniform and the insulation performance is ensured.

The following known techniques have been proposed for a high-voltage transformer having a similar structure from the same viewpoint of insulation performance.

Japanese Unexamined Patent Publication Nos. 2-9109 and 2
Both of these two known techniques include a primary winding and a secondary winding that are arranged around an iron core provided with a gap in a magnetic path in order to reduce the coupling coefficient between the primary winding and the secondary winding. With respect to the secondary winding, the number of secondary windings divided and wound is increased as the gap is closer to the secondary winding, so that the potential distribution is made uniform and the insulation performance is secured.

[0007]

However, the above-mentioned known technique has the following disadvantages. Generally, the secondary winding of an automobile ignition coil has a large number of turns, from 5000 turns to 12000 turns in total, and about 500 to 1000 turns are wound per groove of a bobbin which is divided and wound. Looking at the winding work of a certain groove, first, in the lowest stage on the most iron core side, winding is performed axially in order from the groove end face, and when it reaches the end face on the opposite side, it shifts from the upper stage to the second stage. Then, this time, it winds in the axial direction in the opposite direction to the bottom. That is, for each groove, winding is performed in a zigzag manner from the lowermost stage.

However, in the prior art, since the bottom surface of each groove of the secondary winding bobbin is inclined with respect to the axial direction, when winding as described above, the winding start and the winding start in each groove. It is necessary to accurately position the end in the axial direction and the position in the direction perpendicular to the axis, which complicates the winding work. Also, during or after the winding work, winding pressure causes a drop in the windings that would otherwise cause the windings in the stages that are separated from each other in the direction perpendicular to the axis to come into contact with each other. May occur. Further, in the known art, since the axial length of the groove of the secondary winding bobbin is different for each groove, when performing the winding as described above, the axial position of the winding start and the winding end is set in each groove. It is necessary to accurately position each time,
The winding work becomes complicated. Further, in the known art,
The primary winding and the secondary winding have a structure in which they are separately wound around two iron cores provided separately via a gap, and the primary winding and the secondary winding are arranged around the same iron core. It is not directly applicable to the automotive ignition coil.

On the other hand, a partition wall separates between the groove in which the dividedly wound secondary winding is arranged.
The winding inside one groove and the winding inside the groove next to it
They are connected by a crossover wire connected to a passage formed by cutting into this partition wall. As mentioned above, when winding a coil, the winding is performed in a zigzag manner from the bottom of the groove to the top of the groove. Therefore, the crossover wire is the winding of the top of one groove and the bottom of the adjacent groove. The winding wire is connected obliquely to the axial direction, and the passage for connecting the crossover wire is formed by cutting the partition wall to a large extent in order to facilitate the winding work. Therefore, during or after the winding work, of the secondary windings other than the crossover wire, those that are close to this passage are pushed out toward the passage side by the winding pressure and partially enter the passage, and are adjacent to each other via the partition wall. Proximity / contact between the secondary windings in the matching groove, or proximity / contact between the crossover wire and the secondary winding in the groove may occur. Therefore, if the potential difference between them is large at this time, dielectric breakdown may occur here.

However, in the above-mentioned known arts, the structure of the passage for connecting the crossover wire is not clarified, and no consideration is given to the dielectric breakdown due to the structure of the passage.

A first object of the present invention is to provide an ignition coil for an automobile, which can make a potential distribution uniform and prevent dielectric breakdown.

A second object of the present invention is to provide an ignition coil for an automobile, which can make the electric potential distribution uniform and prevent the dielectric breakdown in the passage connecting the wires.

A third object of the present invention is to provide an automobile ignition coil capable of simplifying the winding work and making the potential distribution uniform and preventing dielectric breakdown.

[0014]

In order to achieve the above first and second objects, according to the present invention, an iron core is used as a shaft center and is wound around a primary winding bobbin arranged on the outer periphery of the iron core. A primary winding and a secondary winding divided into a secondary winding bobbin provided with a plurality of grooves formed on the outer periphery of the primary winding and partitioned by a plurality of partition walls. In an automobile ignition coil having 2 which is divided and wound around the plurality of grooves.
Each of the secondary windings is configured so that the number of winding steps around the secondary winding bobbin decreases in the axial direction of the secondary winding bobbin from the low potential side to the high potential side of the potential distribution in the groove during excitation. Arranged, and each of the plurality of partition walls is arranged so that the thickness of each of the partition walls increases in the axial direction from the low potential side to the high potential side,
Ignition for an automobile having a passage for connecting a crossover wire connecting a secondary winding wound in one groove and a secondary winding wound in the other groove of grooves located on both sides of each A coil is provided.

Preferably, in order to achieve the above first to third objects, in the ignition coil for an automobile, each of the plurality of grooves is a rectangle having the same axial cross section as each other. An ignition coil for a vehicle is provided, which is arranged in a line in a direction.

Further preferably, in order to achieve the above first to third objects, in the ignition coil for an automobile, each of the plurality of partition walls has the same height, and the partition walls have the same height in the axial direction. An ignition coil for an automobile is provided, which is arranged in a row.

Further, in order to achieve the above first and third objects, according to the present invention, the primary winding is wound around a primary winding bobbin which has an iron core as an axis and is arranged on the outer periphery of the iron core. Ignition for an automobile having a wire and a secondary winding dividedly wound on a secondary winding bobbin provided with a plurality of grooves arranged on the outer periphery of the primary winding and partitioned by a plurality of partition walls In the coil, each of the plurality of grooves has a rectangular shape in which the cross-sectional shapes of the secondary winding bobbin in the axial direction are the same, and the grooves are arranged in a line in the axial direction. Provided.

Further, in order to achieve the above first and third objects, according to the present invention, the primary winding is wound around a primary winding bobbin which has an iron core as an axis and is arranged on the outer periphery of the iron core. Ignition for an automobile having a wire and a secondary winding dividedly wound on a secondary winding bobbin provided with a plurality of grooves arranged on the outer periphery of the primary winding and partitioned by a plurality of partition walls In the coil, each of the plurality of partition walls has the same cross-sectional shape in the axial direction of the secondary winding bobbin, and is arranged at equal intervals in the axial direction in a row. A coil is provided.

[0019]

In the present invention constructed as described above, by disposing the number of winding steps of the secondary winding divided and wound in a plurality of grooves so as to decrease from the low potential side to the high potential side, The potential gradient in the groove is originally too small and the potential difference in the groove is originally too small.By increasing the number of windings in the groove on the low potential side, the potential difference in the groove can be made large, and conversely the potential gradient becomes non-linear and the potential difference in the groove becomes large. By reducing the number of windings in the groove on the excessively high potential side, the potential difference in the groove can be reduced, the potential difference in the groove in all the grooves can be made equal, and the potential distribution can be made uniform. At this time, the partition walls are arranged so as to increase in the axial direction of the secondary winding bobbin from the low potential side toward the high potential side, so that the higher the potential gradient is, the higher the voltage gradient is. The secondary windings other than the crossover wire enter into the passage for connecting the crossover wire under winding pressure, causing the secondary windings in adjacent grooves to come close to each other or come into contact with each other through the partition wall, or cross over. It is possible to prevent the wires from coming close to or contacting the secondary winding in the groove, and prevent the occurrence of dielectric breakdown.

Further, by arranging the grooves having the same rectangular sectional shape in the axial direction of the bobbin and arranged in a line in the axial direction, or by arranging partition walls having the same height in a line in the axial direction of the bobbin. When winding the secondary winding bobbin, the bottom surface of each groove is inclined with respect to the axial direction, or the axial length of the groove of the secondary winding bobbin is different from the known technology, which is different from the known technique. Moreover, the relative positions of the winding start and the winding end in the axial direction and the direction perpendicular to the axis are the same in each groove, and it is not necessary to position each groove with high precision each time, and the winding work can be simplified.

Furthermore, in the present invention, the bobbins have the same rectangular sectional shape in the axial direction and are arranged in a line in the axial direction, so that when winding is performed, the start and the end of winding are wound in each groove. The relative position in the axial direction and the relative direction in the axis and the vertical direction are the same, and it is not necessary to perform accurate positioning each time, and the winding work can be simplified.

Further, in the present invention, the partition walls having the same height are arranged at equal intervals in a row in the axial direction of the bobbin, so that when winding is performed, the axial direction of the winding start and the winding end in each groove is increased. Also, the relative position in the vertical direction with respect to the axis is the same, and it is not necessary to perform accurate positioning each time, and the winding work can be simplified.

[0023]

Embodiments of the present invention will be described below with reference to FIGS. A first embodiment of the present invention will be described with reference to FIGS. The structure of the automotive ignition coil of this embodiment is shown in FIG. In FIG. 2, the ignition coil is applied with a voltage of several hundred volts generated by the action of an igniter (not shown).
Secondary winding terminals 1a, 1b, iron core 6, primary winding bobbin 3 arranged on the outer periphery of shaft 6a of iron core 6, and the primary winding wound around primary winding bobbin 3. Winding 2
And the secondary winding bobbin 5 arranged on the outer periphery of the primary winding 2.
A secondary winding 4 (shown later) which is divided and wound, a high voltage output terminal 9 for generating a high voltage of 30 kV by a mutual induction action of the primary winding 2 and the secondary winding 4, and a secondary A secondary winding lead wire 10 for electrically connecting the winding 4 and the high-voltage output terminal 9,
It has a bottomed case 7 formed of an electrically insulating material such as plastic, and an insulating resin layer 8 formed by casting in the case 7 and made of epoxy resin or the like.

The high voltage output terminal 9 is connected to a spark plug (not shown), and a spark plug gap (not shown) is sparked each time the engine is ignited. Is a high voltage of 20kV to 25kV and a sharp cutting wave is applied.

The detailed structure of the primary winding 2 and the secondary winding 4 is shown in FIG. In FIG. 1, the secondary winding bobbin 5 has a plurality of (five in this embodiment) partitions (6 in this embodiment) formed by being partitioned by partition walls 5a to 5e each having a different thickness. And the secondary windings 4a to 4f are separately wound in these grooves. In addition, these six grooves are formed by arranging rectangular grooves having the same cross-sectional shape in a line in the axial direction (horizontal direction in the drawing) of the secondary winding bobbin 5. That is, the heights of the partition walls 5a to 5e are all the same, and they are arranged at equal intervals in a line in the axial direction (horizontal direction in the drawing) of the secondary winding bobbin 5.

The secondary windings 4a to 4f extend from the low potential side to the high potential side (from right to left in the figure) of the potential distribution in the groove at the time of excitation to the secondary winding bobbin 5. The number of winding stages (the number of stages in the vertical direction in the figure) decreases in the axial direction of the secondary winding bobbin 5, that is, the number of winding stages of the secondary windings 4a to 4f is 4f>4e>4d>4c>4b> 4a. And is configured to decrease. Also, the partition walls 5a to e
Is such that the respective thicknesses increase in the axial direction from the low potential side to the high potential side (from the right side to the left side in the figure), that is, the thickness of the partition walls 5a to 5e is 5e <5d. <5
It is configured to increase as c <5b <5a. Furthermore, each of the partition walls 5a to 5e has a crossover passage for connecting crossover wires 53a to 53e connecting the secondary windings wound in the grooves on both sides thereof.

FIG. 3 shows the detailed structure of this passage.
4 and FIG. FIG. 3 shows III-III in FIG.
FIG. 4 is a sectional view taken along line IV-IV in FIG. Figure 3
4A and 4B, the crossover wires 53a to 53e obliquely connect the lowermost secondary winding of one groove and the uppermost secondary winding of the adjacent groove, and connect the crossover wires 53a to 53e. The crossover passages 101a to 101e to be arranged are formed by notching the partition walls 5a to 5e so as to be considerably wide in order to facilitate the winding work (see FIG. 3). That is, since there is no partition wall surface in the notched crossover passages 101a to 101e, the force for horizontally restraining the secondary windings on both sides of the groove does not work. Therefore, during and after the winding work, the secondary windings in the groove, which are close to the passages 101a to 101e, are partially pushed into the passages 101a to 101e by the winding pressure so as to be bulged. The secondary windings 4a to 4f of the grooves adjacent to each other through the partition walls 5a to 5e come into close contact with each other via the partition walls 5a to 5e, or the crossover wires 53a to 5e and the secondary winding 4a in the groove.
~ F is in a state of being close to and in contact with.

Next, the operation of this embodiment will be described. In the present embodiment configured as described above, the number of winding steps of the secondary windings 4a to 4f divided and wound in six grooves is arranged so as to decrease from the low potential side to the high potential side. As a result, the potential gradient inside the groove is originally too small and the potential difference inside the groove is too small.By increasing the number of windings in the groove on the low potential side, the potential difference inside the groove can be made large, and conversely the potential gradient becomes non-linear and the potential difference inside the groove increases. In the groove on the high potential side where is too large, the potential difference in the groove can be reduced by reducing the number of windings, and the potential difference in the groove in all the grooves can be equalized to make the potential distribution uniform. This is shown in FIG.

FIG. 5 shows the distribution of the electric potential of the cutting wave applied to the secondary winding 4 through the high voltage output terminal 9 in the prior art (the thickness of the partition wall and the number of winding steps in each groove are all the same). The distribution in the present embodiment is shown in comparison with the ratio of the total potential difference applied to the secondary winding to the potential difference in each groove on the vertical axis, and the number of turns of the secondary winding on the horizontal axis and from the high potential side. This is the number of groove partition walls. Note that the horizontal axis of this embodiment indicates the number (5a) of the corresponding groove partition wall in FIG.
~ F) are also shown. In the conventional technique indicated by the broken line, the potential gradient on the high potential side (left side in the figure) is steep, and the potential difference in the groove on the highest potential side reaches 20% of the total potential difference, while on the low potential side (see the figure). The potential gradient (middle right) is extremely gentle, and the potential difference in the groove on the lowest potential side is only about 2% of the total potential difference. On the other hand, in the case of the present embodiment shown by the solid line, the potential difference in the groove is about 9 of the total potential difference in all the grooves.
It can be seen that the potential distributions are extremely uniform and the potential distributions are substantially uniform.

Further, in this embodiment, the partition walls 5a ...
By arranging the thickness e to increase in the axial direction of the secondary winding bobbin 5 from the low potential side to the high potential side, the thickness of the partition wall increases as the potential gradient increases. And the secondary windings 4a to 4f cross the passage 101a by winding pressure.
~ Secondary winding 4 of groove which enters into e and adjoins through the partition wall
It is possible to prevent the occurrence of dielectric breakdown by suppressing the proximity and contact between a to f or the proximity and contact between the crossover wires 101a to e and the secondary windings 4a to f in the groove. be able to.

Further, the partition walls 5 in which the grooves have the same rectangular sectional shape in the axial direction in the secondary winding bobbin 5 and are arranged in a line in the axial direction, or have the same height.
By arranging a to e at equal intervals in a line in the axial direction of the bobbin, the bottom surface of each groove of the secondary winding bobbin is inclined with respect to the axial direction, or the axial direction of the groove of the secondary winding bobbin is increased. Unlike the known technique in which the length varies depending on each groove, the relative positions in the axial direction of the winding start and the winding end and in the direction perpendicular to the axis are the same in each groove when winding is performed, and positioning is performed with high accuracy in each case. There is no need and the winding work can be simplified.

As described above, according to this embodiment,
Since the number of winding stages of the secondary windings 4a to 4f divided and wound in six grooves is arranged so as to decrease from the low potential side to the high potential side, the potential difference in the grooves in all the grooves is made equal and the potential is made equal. The distribution can be made uniform. At this time, since the thicknesses of the partition walls 5a to 5e are arranged so as to increase in the axial direction of the secondary winding bobbin 5 from the low potential side to the high potential side,
Proximity / contact between the secondary windings 4a-f of adjacent grooves via the partition walls 5a-e, or closeness / contact between the crossover wires 53a-e and the secondary windings 4a-f in the grooves may occur. It is possible to suppress and prevent dielectric breakdown in the crossing passages 101a to 101e. In addition, the secondary winding bobbin 5 of each groove has the same rectangular sectional shape in the axial direction and is arranged in a line in the axial direction, that is, the partition walls 5a to 5e having the same height are arranged at equal intervals in the secondary winding bobbin. Since they are arranged in a line in the five-axis direction, it is not necessary to accurately position each groove when winding, and the winding work can be simplified.

A second embodiment of the present invention will be described with reference to FIG. The structure of the automobile ignition coil of this embodiment is shown in FIG. Parts common to the first embodiment are designated by common numbers. In FIG. 6, the secondary coil bobbin 15 is different from the ignition coil for automobiles of the first embodiment shown in FIG.
Each of the partition walls 15a to f has seven grooves formed by being partitioned by the partition walls 15a to f, and the secondary windings 14a to 14g are separately wound in those grooves, and the thickness of each of the partition walls 15a to f is all. It is the same point. The other points are almost the same as in the first embodiment.

According to this embodiment, as in the first embodiment,
Since the number of winding steps of the secondary windings 14a to 14g divided and wound in seven grooves is arranged so as to decrease from the low potential side to the high potential side, the potential difference in the grooves in all the grooves is made equal and the potentials are made equal. The distribution can be made uniform. In addition, the secondary winding bobbin 15 of each groove has the same rectangular sectional shape in the axial direction and is arranged in a line in the axial direction, that is, the partition walls 15a to 15f having the same height are arranged at equal intervals in the secondary winding. Since the bobbins 15 are arranged in a line in the axial direction, it is not necessary to accurately position each groove when winding, and the winding work can be simplified.

In the first and second embodiments, the number of winding stages of the secondary winding divided and wound in the groove is arranged so as to continuously decrease from the low potential side to the high potential side. However, a winding configuration is also conceivable in which some grooves are partially decreased instead of being continuously decreased in all grooves. Also in the first embodiment, a partition wall in which the thickness of all the partition walls is not increased continuously from the low potential side to the high potential side but is partially increased for some partition walls. A configuration is also possible. Even in such a case, the same effect can be obtained for that portion.

[0036]

According to the present invention, the number of winding steps of the secondary winding divided and wound in a plurality of grooves is arranged so as to decrease from the low potential side to the high potential side. The potential difference in the groove can be equalized to make the potential distribution uniform. At this time, since the thickness of the partition wall is arranged so as to increase in the axial direction of the secondary winding from the low potential side to the high potential side, the proximity of the secondary windings of the adjacent grooves through the partition wall. It is possible to suppress contact, or proximity / contact between the crossover wire and the secondary winding in the groove, and prevent dielectric breakdown in the passage connecting the crossover wire. In addition, since the grooves have the same rectangular cross-sectional shape in the bobbin axial direction and are arranged in one row in the axial direction, or partition walls having the same height are arranged in one row in the bobbin axial direction at equal intervals, so that when winding In addition, it is not necessary to accurately position each groove, and the winding work can be simplified.

Further, according to the present invention, since the cross-sectional shape of each groove in the axial direction of the bobbin is the same rectangle and they are arranged in a line in the axial direction, it is necessary to accurately position each groove when winding. Without winding work can be simplified.

Further, according to the present invention, since the partition walls having the same height are arranged at equal intervals in one line in the bobbin axial direction, it is not necessary to accurately position each groove when winding. Line work can be simplified.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a detailed structure of a primary winding and a secondary winding in an automobile ignition coil according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing the structure of an automobile ignition coil.

FIG. 3 is a detailed structural diagram of a passage.

FIG. 4 is a detailed structural diagram of a passage.

FIG. 5 is a diagram showing a potential distribution applied to a secondary winding.

FIG. 6 is a vertical cross-sectional view showing a detailed structure of a primary winding and a secondary winding of an automobile ignition coil according to a second embodiment of the present invention.

[Explanation of symbols]

 2 primary winding 3 primary winding bobbin 4 secondary winding 4a to f secondary winding 5 secondary winding bobbin 5a to e partition wall 6 iron core 6a axial center portion 14a to g secondary winding 15 secondary Winding bobbin 15a-f Partition wall 53a-e Crossover wire 63a-f Crossover wire 101a-e Crossover passage

Claims (5)

[Claims] 1. A primary winding wound around a primary winding bobbin having an iron core as an axial center and arranged on the outer periphery of the iron core, and a plurality of partition walls arranged on the outer periphery of the primary winding. In a vehicle ignition coil having a secondary winding bobbin divided and wound on a secondary winding bobbin having a plurality of grooves formed in each of the grooves, each of the secondary windings divided and wound on the plurality of grooves is
The number of winding steps around the secondary winding bobbin is 2 from the low potential side to the high potential side of the potential distribution in the groove during excitation.
The partition walls are arranged so as to decrease in the axial direction of the next winding bobbin, and each of the plurality of partition walls has its thickness increasing in the axial direction from the low potential side toward the high potential side. It has a passage for arranging and connecting a crossover wire that connects a secondary winding wound in one groove and a secondary winding wound in the other groove of grooves located on both sides of each. Ignition coil for automobiles. 2. The automobile ignition coil according to claim 1, wherein each of the plurality of grooves is a rectangle having the same axial cross section and is arranged in a line in the axial direction. Ignition coil for automobiles. 3. The automobile ignition coil according to claim 1, wherein each of the plurality of partition walls has the same height and is arranged at equal intervals in the axial direction. Ignition coil. 4. A primary winding wound around a primary winding bobbin arranged on the outer periphery of the iron core as an axis, and a plurality of partition walls arranged on the outer periphery of the primary winding. An ignition coil for an automobile, comprising: a secondary winding bobbin having a plurality of grooves formed therein; and a secondary winding that is separately wound on the secondary winding bobbin, wherein each of the plurality of grooves has an axial direction of the secondary winding bobbin. 2. The ignition coils for automobiles are characterized in that the cross-sectional shapes thereof in are the same as each other and are arranged in a line in the axial direction. 5. A primary winding wound around a primary winding bobbin having an iron core as an axial center and arranged on the outer periphery of the iron core, and a plurality of partition walls arranged on the outer periphery of the primary winding. An ignition coil for an automobile, comprising: a secondary winding bobbin having a plurality of grooves formed therein; and a secondary winding separately wound on the secondary winding bobbin, wherein each of the plurality of partition walls has an axis of the secondary winding bobbin. An ignition coil for an automobile, which has the same cross-sectional shape in the same direction and is arranged at equal intervals in a line in the axial direction.