JPH1167559A - Ignition coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition coil with a primary coil field, used effectively and a reverse bias field adequately applied, in which a magnet member for the reverse bias field is easily and surely positioned. SOLUTION: An ignition coil 20 has a transformer part 35 with a primary coil 25 and a secondary coil 27 outside a core 23, and an outer tube-shaped auxiliary coil 33 around the transformer part 35. A ring-shaped magnet member 21 having inner and outer faces 21a and 21b, magnetized with opposite polarities is fitted at an outer circumferential part of the core 23 by using a holding member 22. Then, the magnetic member 21 generates a magnetic field opposite to the field generated from the primary coil 25. The reverse magnetic field is applied to the core 23 and the auxiliary core 33. The holding member 22 is positioned by fitting a fitting part 43 of the holding member 22 to a recessed fitting part 31b of a bobbin 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil used for an internal combustion engine of an automobile, and more particularly to an ignition coil of an independent ignition type inserted into a plug hole of an engine.

[0002]

2. Description of the Related Art A conventional ignition coil inserted into a plug hole of an automobile engine is disclosed in Japanese Patent Application Laid-Open No. Hei 8-213259. As shown in FIG. 17, the ignition coil adopts an open magnetic circuit structure including a primary coil 3 and a secondary coil 5 around a rod-shaped magnetic core 1, thereby achieving a reduction in size and diameter. At the same time, magnetic leakage is prevented by providing a cylindrical auxiliary core 9 on the outer peripheral portion of the transformer portion 7 in which the primary coil 3 and the secondary coil 5 are wound inside and outside of each other.

In this ignition coil, a plate-shaped magnet member 11 for applying a reverse bias to a magnetic field B1 generated by the primary coil 3 is disposed at one end or both ends of the magnetic core 1. I have. This magnet member 11
The magnetic flux density in the magnetic core 1 magnetized by the primary coil 3 is reduced, and the residual magnetization of the magnetic core 1 due to the magnetic field B1 of the primary coil 3 is reduced by the holding force of the magnet 11,
Thereby, the amount of change in the magnetic flux density in the magnetic core 1 when the DC voltage is intermittently applied to the primary coil 3 is increased, and the energy extraction efficiency of the secondary coil 5 is improved.

[0004]

However, in the above-mentioned ignition coil, the auxiliary core 9 for assisting the magnetic core 1 is provided, but the magnetic path is divided between the magnetic core 1 and the auxiliary core 9. However, there is a problem that the magnetic field B1 generated in the primary coil 3 cannot be used effectively, and energy cannot be efficiently extracted.

At the end of the magnetic core 1, a primary coil 3
As shown in FIG. 17, the magnetic field B1 generated by the magnetic core 1 extends from the end of the magnetic core 1 to the end of the auxiliary core 9 as shown in FIG.
17 includes many magnetic fields B1 extending along a direction perpendicular to the axial direction of the ignition coil. In the above-described ignition coil, the magnetic field A1 generated by the magnet member 11 corresponds to FIG.
Is formed along the thickness direction of the magnet member 11, that is, along the axial direction of the magnetic core 1, the magnetic field B 1 generated between the magnetic core 1 and the auxiliary core 9 by the primary coil 3.
Is formed between the magnetic core 1 and the auxiliary core 9 so as to avoid the magnet member 11 without being reduced by the magnet member 11. For this reason, the reverse bias magnetic field A1 generated by the magnet member 11 cannot be effectively repelled against the magnetic field B1 of the primary coil 3, and there is a problem that an increase in the secondary output cannot be obtained even in this respect. FIG. 18 shows a composite magnetic field C1 of a magnetic field B1 generated by the primary coil 3 and a magnetic field A1 provided by the magnet member 11, and is formed so as to avoid the magnet member 11 without reducing the composite magnetic field C1. Is shown.

[0006] In view of the above problems, the present invention can effectively utilize the magnetic field generated by the primary coil,
It is an object of the present invention to provide an ignition coil which can apply an appropriate reverse bias magnetic field to a magnetic field generated by a primary coil and can easily and reliably position and fix a reverse bias magnet member.

[0007]

A technical means for achieving the above object is that a primary coil to which a DC voltage is intermittently applied and a secondary coil for taking out the induced electromotive force are wound. An ignition coil in which an ignition coil main body is formed by providing a transformer portion on the outer peripheral portion of the rod-shaped magnetic core and providing a cylindrical auxiliary core on the outer peripheral portion of the transformer portion, which is formed in a ring shape, A magnet member magnetized such that an inner peripheral portion and an outer peripheral portion thereof have opposite magnetic poles, and an axis of the magnetic core that holds the magnet member and connects the magnet member between the magnetic core and the auxiliary core. A holding member that is positioned and fixed to the ignition coil body in a state of being inserted into an outer peripheral portion of the magnetic core in the vicinity of an end of the transformer portion along a core direction. Characterized in that applying a magnetic field of the magnetic field in the opposite direction to the primary coil is generated by the magnet member which is held by the member to the magnetic core and the auxiliary core.

Preferably, the holding member is provided with a ring-shaped magnet holding portion inserted between the magnetic core and the auxiliary core, and the magnet holding portion is opened on one side where the magnet member is fitted. A ring-shaped magnet accommodating groove is provided, and an inwardly protruding engaging claw for engaging the magnet member pushed into the magnet accommodating groove is provided at an opening of the magnet accommodating groove, and the holding member; As the holding member is pushed between the magnetic core and the auxiliary core in the vicinity of the end of the transformer section, the ignition coil main body is fitted with the holding member. It is preferable to provide a locking portion and a locked portion for positioning and fixing the holding member.

Preferably, the magnet member has a shape obtained by equally dividing a donut-shaped member into a plurality of pieces along the radial direction, and each inner peripheral portion and each outer peripheral portion have opposite magnetic poles. While a plurality of permanent magnets magnetized are combined and configured, the holding member is provided with a ring-shaped magnet holding portion inserted between the magnetic core and the auxiliary core, and the magnet holding portion includes A ring-shaped magnet accommodating groove is formed on the outer peripheral surface side into which a plurality of permanent magnets are fitted from the periphery, and the respective permanent magnets pushed into the magnet accommodating grooves are locked in the openings of the magnet accommodating grooves. An inwardly protruding locking claw is provided, and the holding member and the ignition coil body to which the holding member is attached are attached to the magnetic core and the auxiliary core in the vicinity of the end of the transformer section. Preferably provided a locking portion and a locked portion for positioning and fixing the holding member engage each other with to being forced between the.

[0010] More preferably, the locking portion projects from a bottom of the magnet holding portion of the holding member,
An inwardly projecting locking claw is provided at the tip of the locking portion,
The engaged part having an engaging recess for engaging with the engaging claw of the holding member at an end of a bobbin around which the primary coil or the secondary coil is wound, which is located near the end of the transformer unit. It is preferable to provide a joint.

Preferably, the magnet member is embedded in the ring-shaped holding member, and the holding member and the ignition coil body to which the holding member is attached are provided with the holding member. It is preferable to provide a locking portion and a locked portion that engage with each other as they are pushed between the magnetic core and the auxiliary core near the end of the transformer portion to position and fix the holding member. .

Further, preferably, the magnet member has a shape obtained by equally dividing a donut-shaped member into a plurality of pieces along a radial direction, and each inner peripheral portion and each outer peripheral portion have opposite magnetic poles. It is preferable to combine a plurality of permanent magnets that are magnetized.

[0013] Preferably, the locking portion is provided on an inner peripheral portion of the holding member, and the locked portion is provided on an outer peripheral portion of the magnetic core.

[0014]

FIG. 1 is a sectional view showing a configuration of an ignition coil 20 according to a first embodiment of the present invention. FIG. 2 is a plan view of a magnet member 21 provided in the ignition coil 20. FIG. 3 shows the magnet member 21.
FIG. 4 is a sectional view of the ignition coil 2 of FIG.
FIG. 5 is a cross-sectional view of the holding member 22 provided in the ignition coil 20, and FIG. 6 is a cross-sectional view showing a configuration of a magnet mounting portion of the ignition coil 20 of FIG.

The ignition coil 20 has a cylindrical magnetic core 23 formed by laminating electromagnetic steel sheets, a primary coil 25 and a secondary coil 27 wound respectively, and a first magnetic core 23 provided on the outer peripheral portion of the magnetic core 23. And the second bobbin 2
9, 31; a cylindrical auxiliary core 33 provided on the outer periphery of the first and second bobbins 29, 31; a donut-shaped magnet member 21; And a holding member 22 that is positioned and fixed in a state of being fitted into the outer peripheral portion, and has a configuration suitable for reduction in size and diameter so as to be provided in a plug hole of an engine.
Here, the magnetic core 23, the primary coil 25 and the secondary coil 2
The first and second bobbins 29 and 31 around which the coil 7 is wound and the auxiliary core 33 constitute an ignition coil body.

The first and second bobbins 29 and 31 are mounted in a state where the first bobbin 29 is placed inside and outside so that the first bobbin 29 is on the outside. The length of the magnetic core 23 in the axial direction is longer than that of the first bobbin 29.
9 and 31, the magnet members 21 are mounted so that their ends, here the upper ends, are aligned. The primary coil 25 and the secondary coil 27 wound around the first and second bobbins 29 and 31 form the transformer unit 3.
5, and the cylindrical auxiliary core 33 is mounted so as to cover the outer periphery of a portion of the transformer section 35 where the primary coil 25 is provided.

The upper end 23 of the magnetic core 23 and the auxiliary core 33
a and 33a are arranged in the transformer section 35 while being aligned with each other.
Projecting a predetermined length from the upper end of the magnet member 2
1 through the holding member 22 so that the inner peripheral portion 21a and the outer peripheral portion 21b are connected to the outer peripheral surface of the magnetic core 23 and the inner peripheral surface of the auxiliary core 33.
It is arranged outside.

The upper end of the second bobbin 31 is extended upward, and an outer peripheral portion of the extended portion 31a is engaged with a locking claw 45 provided on the holding member 22 described later. A locking recess 31b (locked portion) is formed at a predetermined location.

As shown in FIG. 2 and FIG. 3, the magnet member 21 is integrally formed of a permanent magnet having a donut-like shape obtained by hollowing out the center of a disk.
The inner peripheral portion 21a and the outer peripheral portion 21b are magnetized so that they have opposite magnetic poles. Thereby, the magnet member 21
Inside, a magnetic field along the radial direction is formed between the inner peripheral portion 21a and the outer peripheral portion 21b. Further, two types of magnet members 21 are formed depending on which of the inner peripheral portion 21a and the outer peripheral portion 21b has the N-pole. The direction of the magnetic field applied to the magnetic core 23 and the auxiliary core 33 by the coil 25 is determined.

The holding member 22 is integrally formed of a material suitable for molding such as a rubber material or a resin material. As shown in FIGS. 4 and 5, the magnetic core 23 and the auxiliary core 3 are formed.
3 and four locking portions 43 projecting from the bottom of the magnet holding portion 41 at equal intervals along the circumferential direction from the bottom of the magnet holding portion 41. I have.

The magnet holding portion 41 is provided with a ring-shaped magnet accommodating groove 41a opened on the upper surface side (one surface side) into which the magnet member 21 fits snugly, and is provided outside the opening of the magnet accommodating groove 41a. Four locking claws 41b protruding inward are provided on the wall surface at equal intervals in the circumferential direction, and when the magnet member 21 is pushed into the magnet housing groove 41a, the magnet member 21 is pressed into the magnet housing groove 41a. The upper surface of the magnet member 21 is locked by the locking claw 41b in a state of contacting the bottom surface. Here, the upper surface of the locking claw 41a is a tapered surface so that the magnet member 21 can be easily inserted.

At the tip of each locking portion 43 of the holding member 41, there is provided a locking claw 45 projecting inward from the tip and having a tapered surface 45a on the lower surface side. When the holding member 41 is pushed between the magnetic core 23 and the auxiliary core 33, each of the locking portions 43 is guided by the tapered surface 45 a of the locking claw 45 and the extended portion of the second bobbin 31. When the locking claw 45 reaches the position facing the locking concave portion 31b of the extension portion 31a, the locking claw 43 elastically returns and engages with the locking concave portion 31b, whereby the magnet Holding member 22 holding member 21
Are positioned and fixed at predetermined positions.

In such an attached state, the holding member 22 is configured such that the magnet holding portion 41 has the magnetic core 23 and the auxiliary core 33.
The movement in the radial direction is restricted by being sandwiched between the locking portion 43 and the locking claw 45 provided on the locking portion 43.
The movement in the vertical direction, that is, the axial direction of the magnetic core 23 is restricted by engaging with the locking concave portion 31b provided on the bobbin 31. Thereby, the magnet member 21 is moved to the upper end 23 of the magnetic core 23 near the upper end of the transformer section 35.
a and a position concentric with the magnetic core 23 and the auxiliary core 33 so as to be connected between the “a” and the upper end 33 a of the auxiliary core 33.

In FIG. 6, the thin solid line indicates the magnet member 2.
1 is a magnetic field A2, and a two-dot chain line is a magnetic field B2 generated by the primary coil 25. In the present embodiment, the primary core 25 forms the magnetic core 23 and the auxiliary core 33 at the upper end 23 a of the magnetic core 23.
The magnetic field B2 generated between the auxiliary core 33 and the magnetic core 2
Since the magnet member 21 is formed so as to face the third side, the magnet member 21 has an N pole on the outer peripheral portion 21b side.
The magnet member 21 applies a magnetic field A2 opposite to the magnetic field B2 generated in the magnetic core 23 and the auxiliary core 33 by the next coil 25 to the magnetic core 23 and the auxiliary core 33.

As described above, according to the ignition coil 20 according to the present embodiment, the inner peripheral portion 2a is provided on the outer peripheral portion of the upper end portion 23a of the magnetic core 23 near the upper end portion of the transformer portion 35.
The primary coil 25 is formed by externally fitting a donut-shaped magnet member 21 for reverse bias, which is magnetized so that the outer peripheral portion 1a and the outer peripheral portion 21b have opposite magnetic poles, to make the magnetic circuit structure a semi-closed magnetic circuit structure. The generated magnetic field B2 is efficiently guided between the magnetic core 23 and the auxiliary core 33 via the magnet member 21, and the magnetic core 23 and the auxiliary core 33 are generated by the magnet member 21 while effectively utilizing the magnetic field B2 generated by the primary coil 25.
, A reverse bias magnetic field A2 can be applied effectively.

The reverse bias magnetic field A2 generated by the magnet member 21 is formed along the radial direction of the magnet member 21 between the magnetic core 23 near the upper end of the transformer section 35 and the auxiliary core 33. A reverse bias magnetic field A2 can be appropriately repelled to a magnetic field B2 generated between the magnetic core 23 and the auxiliary core 33 by the primary coil 25,
The magnetic flux density in the magnetic core 23 magnetized by the primary coil 25 can be reduced, and the residual magnetization of the magnetic core 23 due to the magnetic field B2 of the primary coil 25 can be reduced. As a result, the ignition coil 20 can be reduced in size and diameter. , Energy extraction efficiency can be greatly improved.

Further, in the magnetic core 23 and the auxiliary core 33 located near the upper end of the transformer section 35, the magnet member 2
Thus, the magnetic field B2 generated by the primary coil 25 cannot avoid the reverse bias magnetic field A2 generated by the magnet member 21.
It is surely reduced. FIG. 7 is a diagram showing a composite magnetic field C2 between the magnet member 21 and the primary coil 25 in the magnet mounting portion. The magnetic field B2 generated by the primary coil 25 is interrupted near the upper end of the transformer section 35. FIG.

Further, since the magnet member 21 is securely positioned and fixed at a predetermined position by the holding member 22, the magnet member 21 is not displaced, and a suitable and stable reverse bias is applied to the magnetic core 23 and the auxiliary core 33. The magnetic field A2 can be applied, whereby the fluctuation of the secondary output is reduced, and a stable secondary output can be obtained. As a result, the variation of the secondary output between products is reduced, and the ignition coil 20 with stable performance can be manufactured.

Further, just by pushing the holding member 22 between the magnetic core 23 and the auxiliary core 33, the locking claw 45 of the holding member 22 engages with the locking recess 31b provided on the second bobbin 31, Since the holding member 22 is positioned and fixed, the holding member 22 and the magnet member 21 can be securely mounted by a simple mounting operation.

Further, by simply pushing the magnet member 21 into the magnet housing groove 41a of the holding member 22, the magnet member 21 is locked in the magnet housing groove 41a by the locking claw 41b. The member 21 can be securely mounted on the holding member 22 by a simple mounting operation.

In this embodiment, the magnet member 21 is fixed in the magnet accommodating groove 41a by the locking claw 41b.
Instead of providing the locking claws 41b, they may be fixed with an adhesive.

FIG. 8 is a sectional view showing the configuration of an ignition coil 50 according to a second embodiment of the present invention, and FIG. 9 is a diagram showing permanent magnets 53 and 55 constituting a donut-shaped magnet member 51 provided in the ignition coil. , 57,59
10 is a plan view of a holding member 61 provided in the ignition coil 50 of FIG. 8, and FIG.
Is a sectional view of the holding member 61. The ignition coil 50 according to the present embodiment is the same as the above-described ignition coil 20 except that the magnet member 51 and the holding member 61 are used instead of the magnet member 21 and the holding member 22, and the same parts corresponding to each other are the same. And the description is omitted.

The magnet member 51 according to the present embodiment is composed of four permanent magnets 53, 55, 57, 59 having the same shape. Each permanent magnet 53, 55, 57, 59
Has a shape in which a donut-shaped member is equally divided into four along the radial direction, and these permanent magnets 53, 55, 5
The doughnut-shaped magnet member 51 is configured by combining 7, 59.

As shown in FIG. 9, each of the permanent magnets 53, 55, 57, 59 has an inner peripheral portion 53a, 55a, 57
a, 59a and their outer peripheral parts 53b, 55b, 57b, 5
Here, the outer periphery 5
3b, 55b, 57b, and 59b are magnetized so as to have N poles, and each of the magnets has an inner peripheral portion 53a, 55a, 57a, 59a, an outer peripheral portion 53b, 55b, Magnetic fields A3, A4, A5, and A6 extending in the radial direction toward 57b and 59b are formed, respectively. The magnet member 51 including the permanent magnets 53, 55, 57, and 59 can generate a reverse bias magnetic field A2 substantially similar to that of the magnet member 21 described above.

The holding member 61 is integrally formed of a material suitable for metal molding such as a rubber material or a resin material. As shown in FIGS. 10 and 11, between the magnetic core 23 and the auxiliary core 33, as shown in FIGS. A substantially circular ring-shaped magnet holding portion 63 that fits snugly, and 4 having the same configuration as the above-described locking portion 43 of the holding member 22 projecting from the bottom of the magnet holding portion 63.
And two locking portions 65.

The magnet holding portion 63 is formed with a ring-shaped magnet housing groove 63a which is opened on the outer peripheral surface side. The magnet housing groove 63a is formed by four partition portions 63b extending in the radial direction of the magnet holding portion 63. It is partitioned into four magnet housing chambers 63c at equal intervals in the direction. Also, slits 63s are formed at two places in the upper and lower side walls of each magnet accommodating chamber 63c, and the side wall part sandwiched between both slits 63s is a flexible locking portion 63d for locking the magnet. , 63e. Inwardly protruding locking claws 63f, 63g are formed at the distal ends of the flexible locking portions 63d, 63e, that is, at the portions located at the openings of the magnet housing chamber 63c.

When each of the permanent magnets 53, 55, 57, 59 is pushed into each magnet accommodating chamber 63c, the magnet members 53, 5
5, 57 and 59 are flexible locking portions 63 of each magnet accommodating chamber 63c.
When the inner peripheral surfaces of the magnet members 53, 55, 57, and 59 come into contact with the bottom surface in the magnet housing chamber 63c, the flexible locking portions 63 are pushed.
d, 63e return inward, and their locking claws 63f, 63g
Engages with the outer peripheral surfaces of the magnet members 53, 55, 57, 59,
The magnet members 53, 55, 57, 59 are locked. Here, the outer end surfaces of the locking claws 63f, 63g are tapered so as not to hinder the insertion of the permanent magnets 53, 55, 57, 59.

Each magnet accommodating chamber 63c has a permanent magnet 53,5.
5, 57, 59 are fitted and fitted into the magnet storage chamber 63c.
When the 55, 57, 59 are inserted and held, the four permanent magnets 53, 55, 57, 59 form a donut-shaped magnet member 51.

The central through hole of the ring-shaped magnet holding portion 63 is closed by a closing portion 63h in which the upper side wall forming the magnet accommodating groove 63a extends inward. When the member 61 is mounted between the magnetic core 23 and the auxiliary core 33, the closing portion 63h comes into contact with the upper end surface of the magnetic core 23.

The structure of the locking portion 65 of the holding member 61,
The description of the mounting method and the mounting state of the holding member 61 is the same as that of the above-described first embodiment, and will not be repeated.

As described above, also in the present embodiment, the magnetic field B2 generated by the primary coil 25 by the magnet member 51
Can be effectively used, an appropriate reverse bias magnetic field A2 can be applied to the magnetic field B2 generated by the primary coil 25, and the reverse bias magnet member 51 can be easily and reliably placed at a predetermined position by the holding member 61. The same effect as in the first embodiment can be obtained.

Further, by simply pushing the permanent magnets 53, 55, 57, 59 into the magnet accommodating chamber 63a of the holding member 61,
The permanent magnets 53, 55, 57, 59 are formed by the locking claws 63 f, 63 g of the flexible locking portions 63 d, 63 e.
c so that the permanent magnet 5
3, 55, 57, 59 can be securely mounted on the holding member 61 by a simple mounting operation, and the arrangement state of the repulsive permanent magnets 53, 55, 57, 59 can be reliably maintained.

In the first and second embodiments described above, the locking recesses 31b for engaging the locking portions 43, 65 of the holding members 22, 61 are provided in the extension 31a of the second bobbin 31. However, it may be provided on the first bobbin 29 or the magnetic core 23, and the locking claws 45 of the locking portions 43 and 65 are projected outward, and the locking claws 45 are provided on the inner peripheral portion of the auxiliary core 33. The retaining members 22 and 61 may be engaged with any of the holding members 22 and 61 and the holding member mounting portions of the ignition coils 20 and 50 as the holding members 22 and 61 are pushed. It is only necessary that some kind of engaging portion and engaged portion of the uneven structure to be provided be provided.

FIG. 12 is a sectional view showing a configuration of an ignition coil 70 according to a third embodiment of the present invention.
3 is a plan view of a holding member 71 in which the above-described magnet member 51 provided in the ignition coil 70 is embedded, and FIG. 14 is a cross-sectional view of the holding member 71. The ignition coil 70 according to the present embodiment includes a magnet member 51.
Are the same as those of the above-described ignition coil 50 except that the holding member 71 is embedded in the holding member 71 and the structure relating to the structure in which the holding member 71 is fixed to the magnetic core 23. Description is omitted.

The holding member 71 has a donut shape that fits exactly between the magnetic core 23 and the auxiliary core 33, and is made of a material such as a rubber material or a resin material that is suitable for molding. Is molded. Inside the holding member 71, the permanent magnets 53, 55, 5 constituting the magnet member 51 are provided.
7, 59 are embedded in a state of being arranged in a donut shape.

At one opening of the inner peripheral portion of the holding member 71, locking protrusions (locking portions) 71a protruding inward are provided at four positions at regular intervals along the circumferential direction. The magnetic core 23 and the auxiliary core 3 are arranged such that the opening in the inner peripheral portion where the locking projection 71a is not provided is on the front side.
3 is inserted. Correspondingly, the outer peripheral surface of the upper end portion 23a of the magnetic core 23 has a holding member 7
Locking recesses (locked portions) 23b that engage with the locking protrusions 71a to position and lock the locking member 71 are provided continuously in the circumferential direction or at four locations along the circumferential direction. ,
When the locking member 71 is pushed between the magnetic core 23 and the auxiliary core 33, the locking projection 71a of the locking member 71 is engaged with the locking concave portion 23b of the magnetic core 23, and the holding member 71 is moved to a predetermined position. It is designed to be positioned and fixed.

Here, each locking projection 71a of the holding member 71
Has a triangular longitudinal section, and an end face 71b on the downstream side in the insertion direction has a tapered surface inclined with respect to the axial direction of the magnetic core 23 so that the holding member 71 can be easily inserted. The end face 71c on the upstream side in the insertion direction is provided with the magnetic core 23 so that the holding member 71 is firmly retained and held.
Are formed so as to be orthogonal to the axis direction of Correspondingly, the locking recess 23b of the magnetic core 23 is also
It has a triangular cross section corresponding to one locking projection 71a.

As described above, also in the present embodiment, the magnetic field B2 generated by the primary coil 25 by the magnet member 51
Can be effectively used, an appropriate reverse bias magnetic field A2 can be applied to the magnetic field B2 generated by the primary coil 25, and the reverse bias magnet member 51 can be easily and reliably placed at a predetermined position by the holding member 71. The same effect as in the first embodiment can be obtained.

Further, the permanent magnet 5 constituting the magnet member 51
Since 3, 55, 57, and 59 are embedded in the holding member 71, the arrangement state of the permanent magnets 53, 55, 57, and 59 can be reliably held, and the holding member 71
The operation of mounting the permanent magnets 53, 55, 57, 59 to the ignition coil 70 can be omitted, and the operation of assembling the ignition coil 70 can be further simplified.

FIG. 15 shows a holding member 71 according to the third embodiment.
And FIG. 16 is a cross-sectional view of the modification. The holding member 81 has a point that the above-described magnet member 21 made of a single permanent magnet is embedded instead of the magnet member 51, and that one of the inner peripheral portions thereof is used instead of the above-described locking projection 71a. A locking projection 8 having a semicircular longitudinal section on the entire circumference of the opening.
Except for the point at which 1a is formed, the other configuration, the mounting method, and the like are the same as those of the holding member 71. When this holding member 81 is used, instead of the locking recess 23b, a locking recess having a semicircular longitudinal section is formed in the magnetic core 23 in a circumferential direction.

In this embodiment, the locking projections 71a,
81a are provided on the holding members 71, 81 side, and the locking recess 23b is provided.
Are provided on the magnetic core 23 side, but on the contrary, the locking projections 71a, 81
a is provided on the magnetic core 23 side, and the locking recess 23b is
1, 81, or the same concave / convex locking structure may be provided on the outer peripheral surfaces of the holding members 71, 81 and the auxiliary core 3.
3 may be provided on the inner peripheral surface.

In the second and third embodiments, the magnet member 51 divided into four is used. However, the magnet member 51 is not limited to four, but may be divided into two, three, or five or more. Is also good. In this case, the magnet receiving groove 63a provided in the magnet holding portion 63 of the holding member 61 according to the second embodiment.
Is divided into a number of magnet storage chambers 63c corresponding to the number of divisions of the magnet member.

Further, in each of the above-described embodiments, the donut-shaped magnet members 21 and 51 are provided at the upper end portions of the ignition coils 20, 50 and 70. However, the lower end portions of the ignition coils 20, 50 and 70 are provided. May be provided, or may be provided at both upper and lower ends. Further, the magnet members 20, 51 and the holding members 22,
The ring shape of 61, 71, 81 is not limited to the donut shape, and may be changed to another shape such as a rectangular ring according to the shape of the magnet mounting portion between the magnetic core 23 and the auxiliary core 33.

Further, in each of the above-described embodiments, the primary coil 25 and the secondary coil are arranged inside and outside in the transformer section 35. However, the primary coil 25 and the secondary coil are not overlapped in this way, and are arranged in parallel in the axial direction of the magnetic core 23. May be arranged. In this case, the magnet members 21 and 51 are disposed near the end of the primary coil 25 that is not adjacent to the secondary coil 27.

[0055]

As described above, according to the first aspect of the present invention, the outer peripheral portion of the magnetic core near the end of the transformer portion
A primary coil is generated by making a magnetic circuit structure a semi-closed magnetic circuit structure by externally fitting a doughnut-shaped magnet member for reverse bias magnetized so that the inner and outer peripheral parts have opposite magnetic poles. The generated magnetic field is efficiently guided between the magnetic core and the auxiliary core through the magnet member, and the magnetic member effectively applies a reverse bias magnetic field to the magnetic core and the auxiliary core while effectively utilizing the magnetic field generated by the primary coil. You can call.

Further, since the reverse bias magnetic field generated by the magnet member is formed along the radial direction of the magnet member between the magnetic core near the upper end of the transformer section and the auxiliary core, the primary coil is And a reverse bias magnetic field can be accurately repelled against a magnetic field generated between the auxiliary cores, thereby reducing the magnetic flux density in the magnetic core magnetized by the primary coil and remanent magnetization of the magnetic core due to the magnetic field of the primary coil As a result, it is possible to significantly improve the energy extraction efficiency while reducing the size and diameter of the ignition coil.

Further, since the magnet member is securely positioned and fixed at a predetermined position by the holding member, it is possible to apply an appropriate and stable reverse bias magnetic field to the magnetic core and the auxiliary core without displacing the magnet member. As a result, the fluctuation of the secondary output is reduced, and a stable secondary output can be obtained. As a result, the variation in the secondary output between products is reduced, and an ignition coil with stable performance can be manufactured.

According to the second and fourth aspects of the present invention, the magnet member is locked in the magnet housing groove by the locking claw only by pushing the magnet member into the magnet housing groove of the holding member. Therefore, the magnet member can be securely mounted on the holding member by a simple mounting operation.

Further, since the engaging portion and the engaged portion are engaged with each other only by pushing the holding member between the magnetic core and the auxiliary core, the holding member is positioned and fixed. In addition, the magnet member can be securely mounted by a simple mounting operation.

According to the third and fourth aspects of the present invention, it is only necessary to push each permanent magnet into the magnet receiving groove of the holding member.
Since the permanent magnets are locked in the magnet accommodating grooves by the locking claws, each permanent magnet can be securely mounted on the holding member by a simple mounting operation, and the permanent magnets which repel each other can be fixed. The arrangement state can be reliably maintained.

Further, since the engaging portion and the engaged portion are engaged with each other only by pushing the holding member between the magnetic core and the auxiliary core, the holding member is positioned and fixed. In addition, the magnet member can be securely mounted by a simple mounting operation.

According to the fifth to seventh aspects of the present invention, since the magnet member is embedded in the holding member, the operation of mounting the permanent magnet on the holding member can be omitted, and the operation of assembling the ignition coil can be omitted. It can be further simplified.

Further, since the engaging portion and the engaged portion are engaged with each other just by pushing the holding member between the magnetic core and the auxiliary core, the holding member is positioned and fixed. In addition, the magnet member can be securely mounted by a simple mounting operation.

According to the sixth aspect of the present invention, since the plurality of permanent magnets constituting the magnet member are embedded in the holding member, the arrangement of the permanent magnets can be reliably maintained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an ignition coil according to a first embodiment of the present invention.

FIG. 2 is a plan view of a magnet member provided in the ignition coil of FIG.

FIG. 3 is a sectional view of a magnet member provided in the ignition coil of FIG. 1;

FIG. 4 is a plan view of a holding member provided in the ignition coil of FIG. 1;

FIG. 5 is a sectional view taken along line VV of the holding member of FIG. 4;

FIG. 6 is a cross-sectional view illustrating a configuration of a magnet mounting portion in the ignition coil of FIG. 1;

FIG. 7 is a diagram showing a combined magnetic field of a magnet member and a primary coil in the magnet attachment portion of FIG.

FIG. 8 is a cross-sectional view of an ignition coil according to a second embodiment of the present invention.

FIG. 9 is a plan view of four permanent magnets constituting a magnet member provided in the ignition coil of FIG. 8;

FIG. 10 is a sectional view of a magnet member provided in the ignition coil of FIG. 8;

FIG. 11 is a sectional view taken along line XI-XI of the holding member of FIG. 10;

FIG. 12 is a cross-sectional view of an ignition coil according to a third embodiment of the present invention.

FIG. 13 is a plan view of a holding member in which a magnet member provided in the ignition coil of FIG. 12 is embedded.

FIG. 14 is a cross-sectional view of the holding member of FIG.

FIG. 15 is a plan view showing a modification of the holding member of FIG.

FIG. 16 is a sectional view of a modification of FIG.

FIG. 17 is a cross-sectional view showing a configuration of a magnet mounting portion in a conventional ignition coil.

18 shows a magnet member and 1 in the magnet mounting portion of FIG.
It is a figure showing a synthetic magnetic field with a next coil.

[Explanation of symbols]

 20, 50, 70 Ignition coil 21, 51 Magnet member 22, 61, 71, 81 Holding member 23 Magnetic core 23b Locking recess 25 Primary coil 27 Secondary coil 31b Locking recess 33 Auxiliary core 35 Transformer 41, 63 Magnet holding Parts 41a, 63a Magnet accommodation grooves 41b, 63f, 63g Locking claws 43, 65 Locking parts 53, 55, 57, 59 Permanent magnets A2 to A6 Magnetic field by magnet member B2 Magnetic field by primary coil C2 Synthetic magnetic field

Claims (7)

[Claims] 1. A transformer comprising a primary coil to which a DC voltage is intermittently applied and a secondary coil for extracting an induced electromotive force provided on an outer peripheral portion of a rod-shaped magnetic core. An ignition coil in which an ignition coil body is formed by providing an auxiliary core of an ignition coil on an outer peripheral portion of the transformer portion, and is formed in a ring shape, and is magnetized so that its inner and outer peripheral portions generally have opposite magnetic poles. And the magnet member, which holds the magnet member and connects the magnet member between the magnetic core and the auxiliary core, so that the magnetic core near the end of the transformer section along the axial direction of the magnetic core. And a holding member that is positioned and fixed to the ignition coil body in a state of being inserted into an outer peripheral portion, wherein the primary member is held by the magnet member held by the holding member. An ignition coil, wherein a magnetic field in a direction opposite to a magnetic field generated by the coil is applied to the magnetic core and the auxiliary core. 2. A ring having a ring-shaped magnet holding portion inserted between the magnetic core and the auxiliary core, wherein the ring has an opening on one side into which the magnet member is fitted. In addition to providing a magnet-shaped receiving groove having a shape, an inwardly protruding locking claw that locks the magnet member pushed into the magnetic housing groove is provided in an opening of the magnet-receiving groove; As the holding member is pushed between the magnetic core and the auxiliary core in the vicinity of the end of the transformer portion, the holding member is engaged with the ignition coil main body to which the holding member is attached. The ignition coil according to claim 1, further comprising a locking portion and a locked portion for positioning and fixing the member. 3. The magnet member has a shape obtained by equally dividing a donut-shaped member into a plurality of pieces along a radial direction, and each inner peripheral portion and each outer peripheral portion are magnetized so as to have opposite magnetic poles. A plurality of permanent magnets are combined, and the holding member is provided with a ring-shaped magnet holding portion inserted between the magnetic core and the auxiliary core, and the magnet holding portion is provided with the plurality of permanent magnets. Along with providing a ring-shaped magnet housing groove opened on the outer peripheral surface side where the magnet is fitted from the periphery,
An inwardly protruding locking claw for locking each of the permanent magnets pushed into the magnet housing groove is provided in an opening of the magnet housing groove, the holding member, and the ignition to which the holding member is attached. A locking portion for positioning and fixing the holding member by engaging the holding member with the coil near the end of the transformer section between the magnetic core and the auxiliary core in a portion of the coil body. The ignition coil according to claim 1, further comprising a locked portion. 4. The locking portion projects from the bottom of the magnet holding portion of the holding member, and a locking claw protruding inward is provided at a tip end of the locking portion. The engaged portion having a locking concave portion that engages with the locking claw of the holding member is provided at an end of a bobbin around which the primary coil or the secondary coil is wound, which is located near an end. The ignition coil according to claim 2 or 3, wherein: 5. The transformer member is embedded in the ring-shaped holding member, and the holding member is attached to the portion of the ignition coil body to which the holding member is attached. And a locking portion and a locked portion that engage with each other as they are pushed between the magnetic core and the auxiliary core near the end portion to position and fix the holding member. Item 3. The ignition coil according to Item 1. 6. The magnet member has a shape obtained by equally dividing a donut-shaped member into a plurality of pieces along a radial direction, and each inner peripheral portion and each outer peripheral portion are magnetized so as to have opposite magnetic poles. The ignition coil according to claim 5, wherein the ignition coil is configured by combining a plurality of permanent magnets. 7. The ignition coil according to claim 5, wherein the locking portion is provided on an inner peripheral portion of the holding member, and the locked portion is provided on an outer peripheral portion of the magnetic core.