JP2001118741A - Ignition coil and its winding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high voltage coil improving breakdown voltage, regarding an electromagnetic coil and an ignition coil for an internal combustion engine. SOLUTION: In a winding around a bobbin 100 of a secondary coil, it is started to wind from a high voltage side collar 101 and continued to wind toward the other end of low voltage side with a specified number of turns, thereby forming a forward winding. In a return winding in which a specified number of turns is reduced, the coil is wound back in the direction opposite to the forward winding. In the forward winding and the return winding, the number of turns is increased in sequence by a specified number. An inclined surface having an angle θ1 is formed in the high voltage side, and an inclined surface having an angle θ is formed in the direction of winding progress. As a result, the number of turns in the vicinity of the high voltage side collar 101 is reduced, a line voltage can be lowered, and a winding part where winding disorder is little can be arranged on the high voltage side, so that insulating property is improved. Winding diameters in the vicinities of the high voltage side collar 101 and a low voltage side collar 102 are reduced, winding layers on both sides are lowered so that imperfect breakdown voltage due to layer collapse which turns to a problem on the boundary to the collar is excluded, and a coil excellent in breakdown voltage can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for an ignition coil or a high-voltage transformer having a primary coil and a secondary coil and a magnetic material mounted in a gap between the primary coil and the secondary coil. Insulation distance between the coil and the secondary coil,
The present invention relates to an ignition coil that requires a high withstand voltage, such as collapse of a boundary surface between both ends of a secondary coil bobbin and an electric wire layer, and a winding method thereof.

[0002]

2. Description of the Related Art A secondary winding such as an ignition coil and a high-voltage transformer is conventionally known as a so-called skew winding in order to improve insulation characteristics, space efficiency, and shortening of a winding time. . As shown in FIG. 2, the winding starts from the low-pressure side collar 102a, and while the secondary bobbin 100a is being wound, the wire supply nozzle 200 is reciprocated right and left to form a substantially triangular slope, and along the slope. The coil is wound up to the high-pressure brim 101a. JP 9
In Japanese Patent Application Laid-Open No. 129460, after starting winding from the low voltage side to form a substantially triangular slope, continuous winding up to a predetermined winding height, and gradually decreasing the number of windings on the slope toward the high pressure side, or gradually decreasing The insulation characteristics are improved by increasing the line voltage on the high voltage side and the insulation distance from the primary bobbin. Further, in Japanese Patent No. 2630716, while a predetermined number of forward windings from the one end of the secondary bobbin to the other end and a predetermined number of backward windings in the opposite direction are alternately repeated, the winding start and the winding end are performed at the winding height. There is a method of improving the insulation characteristics by reducing the thickness. Alternatively, Japanese Patent Application Laid-Open No. Hei 9-246075 discloses that the inner diameter of a secondary bobbin gradually increases from one end to the other end, the wall thickness gradually decreases, and the number of turns gradually increases. Next, JP-A-9-694
No. 55 discloses that the inclination angle is set to 6 ° or more and 20 ° or less for the purpose of defining the inclination angle of a substantially triangular shape for reducing the line voltage. As to the bobbin shape, there is a type in which a downwardly sloped surface along a traveling direction from a winding start end is formed in advance into a bobbin to form a slanted winding inclined surface as disclosed in Japanese Patent Application Laid-Open No. 60-107815. .

[0003]

In the oblique winding, since the winding layers are continuously laminated on the inclined surface, the winding disturbance generated as the winding proceeds tends to increase toward the end of the winding.

Further, as shown in FIG. 7 (b), although different from the oblique winding according to the present invention, the secondary bobbin is insulated at regular intervals by a conventional winding method. After winding a predetermined number of windings between the partition walls, the winding is successively performed while passing over the next winding part, that is, in a so-called split winding method, the winding is performed by two windings.
A measurement lead wire was taken out from the secondary winding, and the relationship between each measurement site and voltage was measured. As shown in FIG. 7 (a), as a result of measuring the potential from the measurement site 0 to 10 from the low voltage side to the high voltage side, the voltage should increase in proportion to the number of turns.
The high wave number component of about several MHz in the secondary voltage waveform component tends to concentrate potential on the high voltage side, that is, the voltage per turn is relatively higher on the high voltage side than on the low voltage side.

In Japanese Patent Application Laid-Open No. Hei 9-129460, the diameter is reduced as the coil is wound on the high voltage side so that the length of the slope is reduced to reduce the line voltage. Although there is an effect due to the reduced length, large turbulence may propagate, which is particularly problematic on the high voltage side where insulation properties are severe. Japanese Patent No. 2630716 discloses a method of obtaining high insulation characteristics by reducing the diameter of the high voltage side and the low voltage side.
As described in Japanese Patent Application Laid-Open Publication No. H10-216, while the total number of turns in the forward path and the return path is always constant, the winding is sequentially repeated, but the number of turns in the forward path and the return path is equal to or less than a certain value in order to secure the line breakdown voltage. There are restrictions. In this case, if the number of reciprocating windings is set to be small in consideration of the high voltage side where the line voltage is relatively large, it is necessary to make more windings on the low voltage side, and the bobbin length tends to be long. Next, the tilt angle of the skew winding is set to be not less than 6 ° and not more than 20 ° in Japanese Patent Application Laid-Open No. 9-69455, but this is not an absolute condition for winding but an example satisfying various constraints. For example, even if the inclination angle is less than 6 degrees, it becomes possible if the number of turns can be reduced. The inner diameter of the secondary bobbin disclosed in Japanese Patent Application Laid-Open No. 9-246075 gradually increases from one end to the other end, and its thickness gradually decreases.
Regarding the publication where the number of turns gradually increases, the fact that reducing the diameter by reducing the winding height only at the high-pressure end or the low-pressure end at the center of the bobbin is different from the gradual increase and decrease of the publication it can. Next, as for the shape of the bobbin, Japanese Unexamined Patent Publication No. Sho 60-107815 uses a slanted surface formed on the bobbin for the slanting angle of the skew winding, and is effective with a fixed slanting angle specification. There is a problem that it is necessary to make a new one when it is necessary.

[0006]

In order to solve the above-mentioned problems, in the first invention, by starting the winding on the high pressure side instead of the low pressure side, a portion with little winding disturbance is arranged on the high pressure side. I can do it. In addition, when the winding is gradually advanced while repeating the outward winding and the backward winding in the low pressure side direction,
A downwardly inclined surface θ (FIG. 4) corresponding to the amount of forward winding is formed. Further, when the rewinding amount of the backward winding is smaller than the forward winding by a predetermined number, the position of the winding end face on the high voltage side is gradually shifted from the high voltage side to the low voltage side in accordance with the difference, and the winding height and reciprocation are increased. The number of turns gradually increases, and a slope θ1 (FIG. 4) is formed. In this case, the number of turns on the high-pressure side inclined surface can be controlled to be small, so that it is possible to produce an ignition coil having a good withstand voltage characteristic by keeping the line voltage low.

In the second invention, the inclination angle θ in the traveling direction is set to 6
By controlling the inclination angle and the number of turns of the right-sloping slope θ1 from the high pressure side to the low pressure side in the first invention, the number of turns of the reciprocating winding on the slope is kept low, and the winding is performed with a gentle inclination angle θ. There is a synergistic effect of preventing collapse.

In the third aspect of the present invention, the inclination angle θ1 of the slope rising upward from the high pressure side to the low pressure side is determined by the line distance Pt (FIG. 4) and the shift amount s (FIG. 5). The insulation performance can be improved arbitrarily within the allowable range of the inter-voltage.

The fourth invention is suitable for use in the case of optimal adjustment according to the potential distribution on the high voltage side.

According to a fifth aspect of the present invention, the winding height on the high voltage side is kept low below the allowable line voltage, and the remaining windings are distributed to the low voltage side.
By winding, a simple stepped shape can be obtained.

According to a sixth aspect of the present invention, when a rib, which is a member for gradually lowering the height of the bobbin from the start of winding toward the low-pressure side, is provided, the cross section on which the rib is provided can be regarded as a substantially polygonal bobbin. As a result, the rotation speed on the bobbin slightly increases or decreases depending on the rotation angle, so that there is an effect that the electric wire is tightened. In addition, since there is a gap between the ribs, when the bobbin is filled with an epoxy resin and hardened after winding, defects such as voids may occur if the insulation properties are not sufficient and the permeation into the lowermost layer on the high voltage side is not sufficient. This has the effect of preventing it.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention.

(First Embodiment) A first embodiment will be described with reference to FIGS.

In FIG. 3, the ignition coil is a transformer mainly composed of a cylindrical secondary coil 205, a primary coil 206 and an iron core (not shown). Primary coil 20
When the current flowing through 6 is cut off, 1
The voltage proportional to the number of turns between the secondary and secondary coils is
Induced at 05. The secondary coil voltage of the present embodiment is, for example, 30 kV. Next, although not shown, it is common to insert the ignition coil into the plug hole of the engine and fit the high-pressure side of the coil with the electrode of the plug. A secondary electrode is installed as the side. In addition, since the electromagnetic induction is doubled by installing an electromagnetic core material concentrically inside the bobbin and between the primary and secondary coils, the high pressure side of the bobbin is sealed, while the low pressure side far from the plug is closed. Open the bobbin cylinder inside diameter,
As a structure for inserting a rotating shaft at the time of secondary bobbin winding, the high-pressure side and the low-pressure side are distinguished by a bobbin shape.

FIG. 2 is a view showing a conventional example of the winding of a secondary coil. The winding on the secondary bobbin is started from a low-pressure side collar 102a close to a rotating shaft (not shown) inserted from the low-pressure side. It is common to get started. Next, a suitable substantially triangular slope is formed at the beginning of winding, and the winding is repeated at a predetermined winding height H by repeating the diagonal winding along the slope. Or finish the winding
Alternatively, a method of reducing the length of the slope while gradually reducing the number of reciprocating windings or the like (not shown) is used to reduce the line voltage on the high voltage side.

In FIG. 1, a rotary shaft (not shown) is inserted from the low pressure side as in FIG. 2, but the winding is started from below the wall surface of the high pressure side flange 101 of the secondary bobbin 100, contrary to FIG. . This is because, with respect to the characteristic that the turbulence increases as the winding proceeds, the side having the smaller number of turns is arranged on the high voltage side, and the number of turns on the high voltage side and the inclination angle θ can be appropriately changed. Next, the number of windings of the forward winding and the backward winding is gradually increased while rewinding the winding in the forward winding by a predetermined number of times and the backward winding by a predetermined number less than the forward winding in the opposite direction to the forward winding, and the slope is increased to the right toward the high pressure side. In the direction toward θ1 and toward the low pressure side, a winding layer having a downwardly inclined surface θ is formed, and the process is repeated until the winding height becomes h at P1. After that, the winding height h is changed to P2
The last forward winding is performed from P2 so that the winding ends at P3, and the winding ends.

Next, the details of the winding will be described with reference to FIGS. First, numerals 1, 20, 36... 696 in FIG. 4 indicate the total number of turns from the start of winding. Outbound winding is 1-2
0, or 37 to 72 etc., the return winding is 2
1 (not shown) to 36, or 73 (not shown) to 104. Therefore, one round trip of the outward trip and the return trip is 1 →
20 → 36 or 37 → 72 → 104. In FIG. 5, the winding order is 1 → 20 → 36 → 37 → 72 → 104.
It changes like…. An actual example of the number of turns at that time is shown in FIG.
As shown in (b), it starts with 20 turns on the outbound route, 16 turns on the inbound route, 36 turns on the outbound route, 32 turns on the inbound route, and 52 turns on the outward route. The inclination angle θ1 is formed by shifting in the low pressure side direction with a small number of windings. θ1 is determined by the shift amount s, that is, the winding pitch Pt, and is determined by θ1 ≒ tan ⁻¹ (2 × wire diameter / 4 × Pt) in the present embodiment.

Next, in FIG. 4, for the inclination angle θ in the low pressure side direction, the winding width W is determined in advance in the forward winding (for example, 1.
2 mm) This is defined as one unit of the shift amount of the winding advance in the low pressure side direction. In the embodiment, the winding pitch Pt is set to 0.06 m.
m and the winding is proceeding 20 turns at a time. θ is lowered by two layers when the winding is advanced by the winding width W, regardless of the number of turns in the return path.
θ ≒ tan ⁻¹ (2 × wire diameter / W).

When θ is measured on an actual winding bobbin, W =
It is approximately 5 ° when the wire diameter is 1.2 mm and the wire diameter is 0.058 mm, which is almost the same as the calculated value of 5.52 °. That is, under these winding conditions, θ can be less than 6 degrees. The inclination angle θ1 was measured at an actual winding bobbin with a forward winding of, for example, 20 turns and a return winding of 10 turns (not shown).

(Second Embodiment) A second embodiment is shown in FIGS.
This will be described with reference to FIG.

In the conventional so-called split winding as shown in FIG. 7B, the secondary bobbin 100b is partitioned by an insulating partition 210 at regular intervals, and after a predetermined number of turns are wound between the partitions. FIG. 7 (a) shows a measurement lead wire taken out of the secondary winding of the bobbin sequentially wound while passing over the next winding part, and the relationship between each measurement site and the voltage is measured. As a result of measuring the potentials from the measurement sites 0 to 10 from the low voltage side to the high voltage side, for example, at 10 kHz frequency components, almost all are constant, but at about 2.5 MHz, more potential concentrates on the specific parts on the high voltage side. I understood that. That is, it was found that the voltage per turn was relatively higher on the high voltage side than on the low voltage side. Therefore, FIG.
Referring to FIG. 6A, the line voltage can be optimized by forming a parabolic inclined surface that matches the potential distribution of the bobbin in FIG. Fig. 5
Can be realized by gradually reducing the shift amount s.

Next, the extra line 105 is provided for the purpose of finely adjusting the total number of turns. In other words, the winding on the slope at the end of the winding is not performed immediately after the winding pitch is increased by expanding the winding pitch in the middle of the slope because the insulation property is degraded. The number of turns can be adjusted with a wire. In this case, there is no problem with the line voltage due to the collapse of the winding layer, which is a problem at the brim boundary, if the number of layers is within a range that satisfies a predetermined line voltage, even if the layer collapses.

(Third Embodiment) A third embodiment will be described with reference to FIG.

In the figure, the winding is started at a constant winding height h1, starting from the high-pressure side flange 101g, and then winding at a winding height h2 from a certain point. First, h1 is set from the number of turns satisfying the line voltage on the high voltage side, and the remaining number of turns is set to h2.
, The winding design can be simplified.

(Fourth Embodiment) A fourth embodiment will be described with reference to FIG.

This embodiment relates to the shape of a bobbin. In the figure, the rib 300 is radially installed on the circumferential surface of the secondary bobbin near the high pressure side flange 101f (for example, 8
), And the height gradually increases as approaching the high-pressure side brim 101f. When winding is started from the high voltage side, the winding surface can be regarded as substantially polygonal.
00 exerts a winding tightening effect, and the winding is stabilized. Furthermore, in the post-winding process, epoxy resin is injected into the winding bobbin and sealed and cured, but when wires are laminated in multiple layers with a small distance between wires, the resin hardly penetrates to the lower layer, There is a possibility that a wire or the like may be generated from the portion and dielectric breakdown may occur. However, since there is a gap between the ribs 300, the epoxy resin can easily penetrate even in the lowermost layer.

[0027]

As described above, according to the present invention,
Since the winding start is on the high voltage side, the winding part with little winding disturbance can be placed on the high voltage side, and the inclined surface is formed so that the number of turns near the high voltage side end gradually increases, so that the withstand voltage characteristics are improved. Can do things. Furthermore, since the diameter of both ends on the high voltage side and the low voltage side is reduced to minimize the height of the winding layer in the vicinity of the brim, there is no occurrence of a breakdown voltage failure near the brim due to collapse of the layer.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional example of an ignition coil.

FIG. 3 is a partial sectional view of an ignition coil.

FIG. 4 is an explanatory sectional view of an ignition coil.

FIG. 5 is a partially enlarged view of an explanatory cross section of the ignition coil.

FIG. 6 is a sectional view showing a second embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between an output voltage of an ignition coil and a measurement site.

FIG. 8 is a diagram showing a third embodiment of the present invention.

FIG. 9 is a sectional view showing a fourth embodiment of the present invention.

[Explanation of symbols]

100: bobbin, 101: high-pressure side brim, 102
... low-pressure side collar, 103 ... line distance, 104 ... electric wire,
105: Auxiliary line, 200: Nozzle, 205: Secondary winding, 206: Primary winding 300: Rib, θ: Incline angle of low-pressure side right-down slope, θ1: Incline angle of high-pressure side right-up slope, H, h: winding height, Pt: winding pitch,
s ... shift amount,

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazutoshi Kobayashi 2520 Address, Takaji, Hitachinaka City, Ibaraki Prefecture Within the Hitachi, Ltd. Automotive Equipment Group (72) Inventor Toshiaki Ueda 2520 Address, Oaza Takaba, Hitachinaka City, Ibaraki Prefecture (72) Inventor Kenji Nakabayashi 2520 Oita Takaba, Hitachinaka-shi, Ibaraki F-term in Hitachi Automotive Equipment Group (reference) 3G019 CA08 KC04 5E002 AA19

Claims (7)

[Claims] 1. A method of winding an ignition coil in which a wire is wound on a bobbin or the like in a plurality of layers and wound obliquely with respect to the axis of the coil. Forward winding, which is wound by a predetermined amount in the lateral direction, in the opposite direction to the forward winding, rewinding by a predetermined amount smaller in the backward winding, winding while sequentially increasing the number of windings of the forward winding and the backward winding, and determining the winding height, A winding method for an ignition coil, characterized in that the number of turns of the forward winding and the backward winding is constant, and the winding is sequentially and alternately finished to have a predetermined inclination angle. 2. The method of winding an ignition coil according to claim 1, wherein the inclination angle of the low pressure side slope formed by the forward winding and the backward winding is less than 6 degrees. 3. The winding method for an ignition coil according to claim 1, wherein an inclination angle of an inclined surface formed by the high-pressure side envelope formed by the forward winding and the backward winding is 90 degrees or less. 4. The winding method for an ignition coil according to claim 1, wherein the slope formed by the forward winding and the backward winding and formed by the high-voltage side envelope is parabolic toward the low-voltage side. 5. The winding of the ignition coil according to claim 1, wherein the winding layer formed by the forward winding and the backward winding has a low winding height on a high voltage side and a high stepped shape on a high voltage side. Method. 6. An ignition coil in which a wire is wound on a bobbin or the like by a plurality of layers, wherein the coil bobbin starts winding at a high pressure side end, and winds a predetermined amount in a low pressure side direction at the other end. After rewinding by a predetermined amount of backward winding in the direction and winding while sequentially increasing the number of turns of the forward winding and the backward winding, the number of windings of the forward winding and the backward winding is substantially constant, and the winding height of the bobbin is substantially reduced. An ignition coil, wherein a winding end is formed by alternately winding a forward winding and a backward winding so as to have a constant angle and an oblique winding angle. 7. An ignition coil in which a wire is wound on a bobbin by a plurality of layers to form an inclined surface with respect to an axis, and a predetermined position on the circumference of the bobbin in the axial direction of the bobbin near the beginning of high-pressure winding. A winding bobbin for an ignition coil, wherein ribs are radially provided at a predetermined angle, and the height of the ribs gradually decreases from a high-pressure side winding start end toward a low-pressure side.