JP2002280237A - Ignition coil for internal combustion engines - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress cracks of an ignition coil due to thermal stresses in internal combustion engines. SOLUTION: A center core 110 is composed of thin strips 110a. A resin layer 154 near one strip 110a, having the maximum width W among the strips, has a thickness t1 greater than a thickness t2 of a resin layer 154 at other parts. This prevents the resin layer 154 and secondary spools 131 continuing thereto from cracking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil for an internal combustion engine (hereinafter, abbreviated as an ignition coil).

[0002]

2. Description of the Related Art The structure of an ignition coil for an automobile is disclosed, for example, in JP-A-11-1115.
As described in Japanese Patent Publication No. 45, a primary coil (outer peripheral coil), a secondary coil (inner peripheral coil) and a gap between these components are coaxially arranged on the outer peripheral side of a rod-shaped central core. Are made of resin material (potting material, casting resin), etc., but since these components have different coefficients of linear expansion, cracks may occur in the components due to thermal stress High in nature.

In view of the above, an object of the present invention is to suppress the occurrence of cracks due to thermal stress in an ignition coil for an internal combustion engine.

[0004]

According to the present invention, there is provided an ignition coil for an internal combustion engine for supplying a high voltage to an ignition device for an internal combustion engine. A central core (110) formed in a substantially cylindrical shape, an inner peripheral coil (130) and an outer peripheral coil (120) wound coaxially with the central core (110); A tube (111) covering the outer peripheral surface, and a resin layer (154) made of a resin material having electrical insulation and filled in a gap between the inner peripheral coil (130) and the tube (111). The core (110) is formed by laminating a thin strip (110a) made of a magnetic material in the radial direction of the central core (110), and further has a maximum width of the resin layer (154). The thin ribbon plate (11
The vicinity of 0a) is characterized in that the thickness of the resin layer is thicker than other portions.

Since the coefficient of linear expansion of the resin layer (154) is smaller than the coefficient of linear expansion of the center core (110), the thermal stress due to the difference in the coefficient of linear expansion (thermal expansion) is reduced. Concentrates on the edge portion (corner) of. This thermal stress is greatest in the vicinity of the thin plate (110a) where the amount of thermal expansion is the largest and the width dimension is the largest.

Therefore, as in the first aspect of the present invention, the thickness of the resin layer (154) in the vicinity of the thin plate (110a) where the width dimension is maximum is the same as the thickness of the resin layer (154) in other parts. Thicker than the resin layer (15
4) It is possible to prevent the occurrence of cracks or the like beforehand.

According to a second aspect of the present invention, there is provided an ignition coil for an internal combustion engine for supplying a high voltage to an ignition device of the internal combustion engine, wherein a central core (110) formed in a substantially cylindrical shape and a central core (110) are provided. ), An inner coil (130) and an outer coil (120) wound coaxially, a tube (111) covering the outer surface of the central core (110), and an inner coil (130). A spool (131) disposed on the inner peripheral side for winding the winding of the inner peripheral coil (130) formed in a substantially cylindrical shape, and filling a gap between the spool (131) and the tube (111). And a resin layer (154) made of a resin material having electrical insulation properties, and the center core (110) is formed by laminating a thin plate (110a) made of a magnetic material in a radial direction of the center core (110). And a spur The inner peripheral surface of the Le (131) (13
1a) The thin plate (110a) having the largest width dimension
, A groove (131b) extending parallel to the axial direction of the central core (110) is provided.

As a result, the thickness of the resin layer (154) in the vicinity of the thin plate (110a) where the width dimension is maximized is greater than the thickness of the resin layer (154) in other parts. As in the first aspect, it is possible to prevent the occurrence of cracks in the resin layer (154) and the like.

Since the center core (110) is formed into a cylindrical shape by laminating the thin strips (110a), the outer peripheral surface thereof has a fine step shape, so that a minute gap is generated.

On the other hand, since a very high voltage is generated in the coil, the center core (110) (particularly,
Corona discharge is likely to occur in the minute gap located between the edge portion) and the coil. When the corona discharge occurs, the tube (111) is worn like the center electrode and the ground electrode of the spark plug are worn.

Therefore, according to the third aspect of the present invention, the tube (111) covering the outer peripheral surface of the central core (110) is
The inner tube (11) located on the side of the central core (110)
1a) and an outer tube (111b) that covers the outside of the inner tube (111a).
The outer tube (111b) is a shrinkable tube whose diameter decreases when heated, and the inner tube (111a) is an outer tube (111b).
Characterized in that the tube is made of a resin which is brought into a molten state at a temperature at which the temperature is reduced.

As a result, the minute gap generated between the tube (111) and the center core 110 is filled with the resin in the molten state (the inner tube (111a)). It is possible to suppress the occurrence of corona discharge in the minute gap generated between (110) and (110).

Therefore, it is possible to prevent the tube (111) from being worn by corona discharge generated in the minute gap, so that high electrical insulation between the coil and the central core (110) can be maintained. .

According to a fourth aspect of the present invention, there is provided an ignition coil for an internal combustion engine for supplying a high voltage to an ignition device for the internal combustion engine, wherein the central core (110) is formed in a substantially cylindrical shape.
And an inner peripheral coil (130) and an outer peripheral coil (120) wound coaxially with the center core (110), and an outer peripheral surface of the center core (110) in contact with the center core (110). And a tube (111) covering the central core (1).
10) is constituted by laminating a thin plate (110a) made of a magnetic material in the radial direction of the central core (110),
At least the outer peripheral side of the tube (111) is filled with a resin material having electrical insulation to form a resin layer (154), and the tube (111) has conductivity.

As a result, the tube (111) has the same potential as the central core (110).
The central core (110) looks like a simple columnar core without any edges and microvoids.

Therefore, the occurrence of corona discharge can be suppressed and the tube (111) can be prevented from being worn, so that high electrical insulation between the coil and the central core (110) can be maintained. it can.

In general, the resin layer (154) is formed of another member (in this example, the secondary spool (1
31)) and the resin layer (1) due to the thermal stress caused by the linear expansion coefficient (thermal expansion amount).
When a crack occurs in the crack (54), the member (secondary spool (131)) adhered to the cracked resin layer (154) also has a crack in the cracked resin layer (154).
Crack together with it (they break together).

Therefore, in the invention according to claim 5, the central core (110) formed in a substantially cylindrical shape and the central core (1) are provided.
10), the inner peripheral coil (13) wound coaxially
0) and the outer peripheral side coil (120) and the center core (11).
0), a tube (111) covering the outer peripheral surface, and an inner peripheral coil (13) disposed on the inner peripheral side of the inner peripheral coil (130).
0) a resin spool (131) wound with a winding;
A resin layer (154) made of a resin material having electrical insulation and filled in a gap between the spool (131) and the tube (111); the resin layer (154) and the spool (1);
31), an elastic member (154) capable of elastic deformation.
a) is provided.

Thus, even if a crack occurs in the resin layer (154), the resin layer (154) can be displaced relative to the inner peripheral surface of the secondary spool (131). The growth of the crack generated in (154) is blocked by the elastic member (154a). Therefore, it is possible to prevent the secondary spool (131) from breaking together with the resin layer (154).

According to the sixth aspect of the present invention, the center core (110) formed in a substantially cylindrical shape by laminating the thin strips (110a) made of a magnetic material;
A cylindrical collar (111c) covering the outer peripheral surface side of the outer cover, a shrinkable tube (111) covering the outer peripheral surface side of the collar (111c) and having a reduced diameter dimension when heated, and a shrinkable tube (111). Located on the outer peripheral side, the central core (1
10), the inner peripheral coil (13) wound coaxially
0) and the outer peripheral side coil (120).

As a result, the concentration of thermal stress at the edge of the central core (110) can be suppressed, so that cracks can be prevented from occurring in the resin layer (154) and the like.

According to the seventh aspect of the present invention, the center core (110) formed in a substantially cylindrical shape by laminating the thin strips (110a) made of a magnetic material;
Tube (111) covering the outer peripheral surface side of
11) An inner peripheral coil (130) and an outer peripheral coil (120) which are located on the outer peripheral side and are coaxially wound with respect to the central core (110). ,
A slit (110b) extending in the longitudinal direction by dividing a part of the thin plate (110a) is provided.

As a result, the ribbon (11)
Since the expansion and contraction in the width direction (direction orthogonal to the longitudinal direction) of 0a) can be absorbed by the slits (110b), the concentration of thermal stress on the edge portion can be suppressed,
Cracks can be prevented from occurring in the resin layer (154) and the like.

Incidentally, since the center core (110) is joined at both ends, the thermal expansion in the longitudinal direction causes
The central portion in the longitudinal direction bends like a bow so as to be most displaced. For this reason, the member located on the outer peripheral side of the center core (110) is the most displaced center core (110).
Receives the largest thermal stress at the center in the longitudinal direction.

Therefore, in the invention according to claim 8, the center core (110) formed in a substantially cylindrical shape and the center core (1) are formed.
10) an inner peripheral coil (130) and an outer peripheral coil (120) which are located on the outer peripheral side and are coaxially wound with respect to the central core (110); It is characterized in that a plurality of core parts (110c), in which thin strips (110a) made of material are laminated and whose longitudinal ends are joined, are arranged in the axial direction.

As a result, the longitudinal dimension of the thin plate material (110a) is reduced, and the maximum displacement due to thermal expansion in the longitudinal direction is smaller than that in the case where the central core (110) is constituted by one core part (110c). Can be reduced.

Therefore, the thermal stress acting on the member located on the outer peripheral side of the center core (110) can be reduced, and cracks occur on the member located on the outer peripheral side of the center core (110). Can be prevented from occurring.

Further, according to the ninth aspect of the present invention, one core component (110c) of the plurality of core components (110c) is provided.
The laminating direction of the ribbon (110a) in (c) is different from the laminating direction of the ribbon (110a) in the other core component (110c).

Thus, the direction of the thermal stress acting on the member located on the outer peripheral side of the central core (110) due to the thermal expansion in the longitudinal direction can be changed between one core component (110c) and another core component (110). 110c).

Therefore, the thermal stress acting on the member located on the outer peripheral side of the center core (110) can be dispersed, so that cracks occur on the member located on the outer peripheral side of the center core 110. Can be prevented beforehand.

According to the tenth aspect of the present invention, the center core (110) formed in a substantially cylindrical shape and the center core (110) are provided.
An inner peripheral coil (130) and an outer peripheral coil (120) which are located on the outer peripheral side and are wound coaxially with respect to the central core (110), the central core (110) and the inner peripheral coil (1)
30) and a resin layer (154) made of a resin material filled in a gap between the resin layer (154) and a filler that increases the mechanical strength of the resin layer (154) is added to the resin layer (154). It is characterized by being.

Accordingly, it is possible to suppress the occurrence of cracks in the resin layer (154) made of the resin material filled in the gap between the center core (110) and the inner peripheral coil (130).

By the way, in the oblique winding, when winding the winding,
Since the wound winding is easily broken, in order to prevent the winding from being broken, the outer shape of the cross section of the secondary spool (131) is set to be a polygon, and when the winding is wound, the winding is wound on the secondary spool (13).
It is desirable to dig into 1).

However, when the secondary spool (131) has a polygonal cross-sectional outer shape, the resin flow is more likely to be disturbed when the secondary spool (131) is molded than in a simple circular cross-sectional outer shape. . When the flow of the resin is disturbed, the orientation of the resin material forming the secondary spool (131) is disturbed, and the mechanical strength of the secondary spool (131) tends to decrease.

On the other hand, the other end in the axial direction of the secondary spool (131) is more strongly constrained by the flange portion (152) than the one end in the axial direction, so that large thermal stress is likely to occur. For this reason, cracks due to thermal stress are likely to occur at the other axial end of the secondary spool (131).

Therefore, according to the present invention, the primary coil (120) and the secondary coil (130) are arranged coaxially, and the center inserted into the shaft core of both coils (120, 130). The core (110) and the primary coil (12
0) is wound, and a substantially cylindrical primary spool (121) formed of resin is wound, and a winding of a secondary coil (130) is wound, and a substantially cylindrical shape formed of resin is formed. A cylindrical housing (1) containing a secondary spool (131), a central core (110), and both coils (120, 130).
51), and a fixing bracket portion (152) provided so as to cover one axial end of the housing. The winding of the secondary coil (130) has a small potential difference between adjacent windings. The secondary spool (131) has a substantially circular outer cross-sectional shape at one axial end, and a polygonal outer cross-sectional shape at the other axial end. It is characterized by the following.

Thus, it is possible to prevent the secondary spool (131) from cracking while preventing the winding from collapsing.

In the twelfth aspect of the present invention, the primary coil (120) and the secondary coil (130) are arranged coaxially, and the center inserted into the axial core of both coils (120, 130). The core (110) and the primary coil (12
0) is wound, and a substantially cylindrical primary spool (121) formed of resin is wound, and a winding of a secondary coil (130) is wound, and a substantially cylindrical shape formed of resin is formed. A cylindrical housing (1) containing a secondary spool (131), a central core (110), and both coils (120, 130).
51), and a fixing bracket portion (152) provided so as to cover one axial end of the housing. The winding of the secondary coil (130) has a small potential difference between adjacent windings. The secondary spool (131) is characterized in that the outer shape in cross section gradually changes from a substantially circular shape to a polygonal shape from one axial end to the other end. I do.

Thus, the secondary spool (131) can be prevented from being collapsed in the same manner as the invention according to the eleventh aspect.
Cracks can be prevented.

Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment)
The ignition coil according to the present invention is applied to a vehicle ignition coil that supplies a high voltage (for example, 30 kV) to a spark plug (ignition device) of a vehicle engine (internal combustion engine). FIG. Ignition coil 10 according to the embodiment
FIG. 2 is an axial cross-sectional view (overall cross-sectional view) of FIG.

Incidentally, the ignition coil 10 according to this embodiment
Reference numeral 0 denotes a stick (stick), which is mounted on a spark plug (not shown).
0 is housed in a plug hole formed in a cylinder head (not shown).

In FIG. 1, reference numeral 110 denotes a rod-shaped center core made of a magnetic material (in this embodiment, a silicon steel plate). As shown in FIG. The lamination core is formed by laminating a plurality of thin strips 110a having different widths W in the thickness direction.

Each of the ribbon plates 110a is welded to both ends in the longitudinal direction of the central core 110 by laser welding, and a primary coil 120 to be described later is attached to the end thereof.
Permanent magnets 112 and 113 having polarities opposite to the direction of the magnetic field induced by the magnetic field are provided.

On the outer peripheral side of the center core 110, a secondary coil (inner peripheral side coil) 130 which is electrically connected to the spark plug side is arranged. Outside the secondary coil 130, the secondary coil 130 A primary coil (outer circumference side coil) 120 to which a control signal from an igniter for controlling a high voltage generated in the coil is input is arranged.

Reference numeral 121 denotes a primary spool (outer peripheral winding frame) for winding the primary coil 120 disposed between the secondary coil 130 and the primary coil 120. The primary spool 121 is made of resin. (In this embodiment, the PPE
It is formed in a substantially cylindrical shape with an electrically insulating material such as resin.

On the outer peripheral surface of the primary spool 121 (between the primary coil 120 and the primary spool 121), P
A thin film 122 made of ET (polyethylene terephthalate) is wound, and the first film 121 prevents the primary spool 121 from completely adhering to a molding resin (a casting resin) described later. It constitutes an adhesion suppressing layer.

Reference numeral 131 denotes a secondary spool (inner winding frame) for winding the winding of the secondary coil 130 disposed between the secondary coil 130 and the center core 110. The spool 131 is formed in an approximately cylindrical shape with an electrically insulating material such as a resin (in the present embodiment, a PPE resin).

The ignition coil 100 is a primary coil 1
20 is output from the secondary coil 130 after the voltage input to the secondary coil 130 is increased, so that the number of turns of the secondary coil 130 is larger than the number of turns of the primary The diameter of the wire is smaller than the diameter of the winding of the primary coil 120, and the winding of the secondary coil 130 is wound around the secondary spool 131 by oblique winding.

As shown in FIG. 3, "skew winding" refers to winding the winding in one end in the axial direction of the spool so as to meander in an oblique direction with respect to the vertical direction of the paper (radial direction of the spool). It is also a winding method from the side to the other end side, and when winding the winding on the spool by this "skew winding", the winding length between adjacent windings is shortened, so that the windings are adjacent The potential difference between the windings can be reduced.

Incidentally, the thickness of the secondary coil 130 (the number of turns of the coil) decreases toward the high voltage side (in this embodiment, the spark plug side of the axial end of the secondary coil 130). It is rolled to be.

Further, on the inner peripheral surface side of the secondary spool 131 (between the secondary spool 131 and the center core 110), FIG.
As shown in FIG. 2, a cushioning member (rubber tube in the present embodiment) 111 for preventing the edge portion (corner portion) of the central core 110 from directly contacting the secondary spool 131 is provided.

Incidentally, the cushioning member (shrinkable tube) 111
Has a diameter reduced by being heated, and the central core 110 is provided with a buffer member (shrinkable tube) 111.
By heating while inserted in the center core 11
The buffer member (shrink tube) 111 is brought into close contact with zero.

A cylindrical outer core 140 made of a magnetic material (in this embodiment, a silicon steel plate) is disposed on the outer side of the primary coil 120. The outer side of the outer core 140 is made of resin. Covered (protected) by housing 150
ing.

As shown in FIG. 1, the housing 150 is composed of approximately three parts. Specifically, the housing 150 covers the outer peripheral side of the outer peripheral core 140 and the ignition coil main body (the primary coil 120 or the secondary coil 120). A cable (not shown) from the igniter so as to cover the first housing portion 151 for protecting the next coil 130 and the like (a portion where the next coil 130 and the like are accommodated) and to cover one axial end (upper side of the paper) of the first housing portion 151. ) Is connected to the bracket 160 for fixing the connector 160 and the ignition coil 100 to the cam cover (not shown).
A first high-voltage terminal 171 and a first high-voltage terminal 171 to which a second housing part 152 integrated with 61 and a lead wire (not shown) provided at an axial end of the secondary coil 130 are connected. And a third housing part (high-pressure tower) 153 in which a second high-voltage terminal 173 for electrically connecting (relaying) a spring 172 made of a conductive material in contact with a terminal of the spark plug is housed.

The interior of the housing 150 (particularly, the interior of the outer core 140) is filled with an electrically insulating casting resin (in this embodiment, an epoxy resin) so that both the coils 120 and 130 and other parts are filled. Is formed with a resin layer 154 to be fixed by molding.

At this time, the inner peripheral surface 1 of the secondary spool 131
As shown in FIG. 4, a groove 131b extending parallel to the axial direction of the central core 110 (perpendicular to the paper surface) is provided in the vicinity of the thin strip plate 110a where the width dimension W is the largest in the 31a. The thickness t1 of the resin layer 154 in the vicinity of the thin plate 110a where W becomes the maximum is larger than the thickness t2 of the resin layer 154 in other portions (t1> t2).
Like that.

Next, the features (effects) of this embodiment will be described.

Since the coefficient of linear expansion of the resin layer 154 is smaller than the coefficient of linear expansion of the center core 110, the thermal stress due to the difference in the coefficient of linear expansion (thermal expansion) is applied to the edge (corner) of the center core 110. Concentrate. The thermal stress is greatest in the vicinity of the ribbon 110a where the width dimension W is maximum, where the amount of thermal expansion differs most.

On the other hand, in the present embodiment, the width W
Resin layer 15 in the vicinity of the ribbon 110a where
4 is the thickness t1 of the resin layer 154 in the other portion.
Since the thickness is larger than that of No. 2, it is possible to prevent the occurrence of cracks in the resin layer 154 and the secondary spool 131 connected thereto.

(Second Embodiment) This embodiment is different from FIG.
As shown in (a), the buffer member (shrink tube) 111
To the inner peripheral side tube 111a located in the center core 110.
The outer tube 111b has a two-layer structure including an outer tube 111b that covers the outside of the inner tube 111a, and the outer tube 111b has a reduced diameter dimension when heated. The outer tube 111b is made of a resin that is in a molten state at a temperature for reducing the size.

Next, the features (effects) of this embodiment will be described.

Since the center core 110 is formed in a cylindrical shape by laminating the thin strips 110a, the outer peripheral surface thereof is
As shown in FIG. 2, since the shape is a fine step, a minute gap is generated.

On the other hand, since a very high voltage is generated in the secondary coil 130 as described above, the center core 110 (particularly, the edge portion), which is a conductor, and the secondary coil 1
Corona discharge is likely to occur in the above-mentioned minute gaps located between the gaps 30 and 30. When the corona discharge occurs, the buffer member (shrinkage tube) 111 wears like the center electrode and the ground electrode of the spark plug wear.

On the other hand, in the present embodiment, when the cushioning member (shrinkage tube) 111 is heated and shrunk, the minute gap generated between the cushioning member (shrinkage tube) 111 and the central core 110 is in a molten state. Resin (inner tube 1
11a), it is possible to suppress the occurrence of corona discharge in the minute gap generated between the buffer member (shrinkage tube) 111 and the central core 110.

Therefore, the buffer member (shrinkage tube) 111 can be prevented from being worn out by the corona discharge generated in the minute gap, so that high electrical insulation between the secondary coil 130 and the center core 110 is maintained. can do.

(Third Embodiment) In the present embodiment, as in the second embodiment, the occurrence of corona discharge is suppressed by the minute gap generated between the buffer member (shrinkable tube) 111 and the central core 110. The purpose is to do so.

Specifically, as shown in FIG. 6 (a), the buffer member (shrinkable tube) 111 is provided with an inner tube 111a located at the center core 110 and an outer tube covering the outer surface of the inner tube 111a. The outer tube 111b has a two-layer structure including the outer tube 111b, and the outer tube 111b has a reduced diameter dimension when heated, and
The inner tube 111a is made of a conductive resin (a resin mixed with a conductive material such as carbon or metal).

As a result, the inner peripheral tube 111a (buffer member 111) has the same potential as the central core 110.
When viewed from the secondary coil 130, as shown in FIG. 6B, the central core 110 looks like a simple columnar core having no edges and no minute voids.

Therefore, the occurrence of corona discharge can be suppressed, so that the buffer member (shrinkage tube) 111 can be prevented from being worn, and the high electrical insulation between the secondary coil 130 and the central core 110 can be improved. Can be maintained.

In this embodiment, the inner tube 1
11a is a conductive resin, but the present embodiment is not limited to this.
The outer diameter side tube 111b is made of a conductive resin, or the buffer member (shrinkage tube) 111 has a one-layer structure.
The buffer member 111 itself may be made of a conductive resin.

(Fourth Embodiment) This embodiment is different from FIG.
As shown in (a), the buffer member (shrink tube) 111
Resin layer 154 formed on the outer peripheral side of the secondary spool 13
1, an elastic member 154a, such as rubber or elastomer, which can be elastically deformed is provided.

Next, the features (effects) of this embodiment will be described.

Normally, since the resin layer 154 is in a state of being very firmly bonded to another member (the secondary spool 131 in this example) which comes into contact with the resin layer, the linear expansion coefficient (thermal expansion amount)
When a crack is generated in the resin layer 154 due to the thermal stress generated at the time, the member bonded to the cracked resin layer 154 is also cracked (co-cracked) together with the cracked resin layer 154.

On the other hand, in the present embodiment, the resin layer 1
Since an elastically deformable elastic member 154a such as rubber or elastomer is arranged between the secondary spool 131 and the secondary spool 131, cracks generated in the resin layer 154 occur as shown in FIG. Even so, the resin layer 154 can be displaced relative to the inner peripheral surface of the secondary spool 131.

Therefore, the growth of cracks generated in the resin layer 154 is blocked by the elastic member 154a, so that the secondary spool 131 can be prevented from breaking together with the resin layer 154.

(Fifth Embodiment) In this embodiment, as shown in FIG. 8, a substantially cylindrical collar 111c is disposed between a cushioning member (shrinkable tube) 111 and a central core 110 to provide a collar. The outer peripheral surface of the central core 110 is covered with 111c, and the outer peripheral side of the collar 111c is covered with a cushioning member (shrinkable tube) 111.

With the configuration described above, the central core 110
Has a structure in which the edge portion is covered with the collar 111c, so that thermal stress can be prevented from concentrating on the edge portion, and the occurrence of cracks in the resin layer 154 and the secondary spool 131 can be prevented beforehand. it can.

In this embodiment, the color 111c is used.
8 is formed of metal, resin, or the like having higher mechanical strength than the cushioning member (shrink tube) 111.
As shown in (b), by making the cross-sectional shape of the collar 111c into a C-shape, the collar 111c can be easily expanded and deformed in its radial dimension.
The mounting property (insertion property) of 1c to the center core 110 is improved.

(Sixth Embodiment) In this embodiment, as shown in FIG. 9, a slit 110b extending in the longitudinal direction by dividing a part of a thin strip plate 110a constituting a central core 110 is provided. The plate 110a is shaped like a tuning fork.

As a result, the thin plate 110 accompanying the temperature change
Since the expansion and contraction of a in the width direction (the direction orthogonal to the longitudinal direction) can be absorbed by the slit 110b, the concentration of thermal stress on the edge portion can be suppressed, and the resin layer 1
Cracks can be prevented from occurring in the secondary spool 54 and the secondary spool 131.

(Seventh Embodiment) In this embodiment, as shown in FIG. 10, a plurality of thin strips 110a are laminated and their longitudinal ends are laser-joined (in this embodiment, two
Of the plurality of core components 110c, and the lamination direction of the ribbon 110a in one core component 110c and the ribbon 110a in the other core component 110c. (In the present embodiment, about 90 °) and the central core 110 is configured.

Next, the features (effects) of this embodiment will be described.

Since both ends of the center core 110 (including the core part 110c) are welded, the center core 110 is bent in a bow shape by thermal expansion in the longitudinal direction so that the central portion in the longitudinal direction is most displaced. For this reason, the members (especially, the secondary spool 131 and the resin layer 154) located on the outer peripheral side of the center core 110 are hardly displaced by the center core 110 that is displaced most greatly.
(The core part 110c is also included.) The central part in the longitudinal direction receives the largest thermal stress.

On the other hand, in the present embodiment, the central core 110 is formed by arranging a plurality of (two in the present embodiment) core parts 110c in the axial direction. The dimension in the direction is reduced, and the maximum displacement due to thermal expansion in the longitudinal direction can be reduced as compared with the case where the central core 110 is constituted by one core component 110c.

Therefore, the members (particularly, the secondary spool 131 and the resin layer 1) located on the outer peripheral side of the central core 110.
Since the thermal stress acting on (54) can be reduced,
Cracks can be prevented from occurring in the members (especially, the secondary spool 131 and the resin layer 154) located on the outer peripheral side of the central core 110.

Further, among the plurality of core parts 110c,
Since the laminating direction of the thin strips 110a in one core component 110c and the laminating direction of the thin strips 110a in the other core component 110c are different, the outer circumferential side of the central core 110 is caused by the thermal expansion in the longitudinal direction. The direction of the thermal stress acting on the located members (especially, the secondary spool 131 and the resin layer 154) is determined by changing the direction of one core component 110c and the other core component 1
10c.

Therefore, the members (particularly, the secondary spool 131 and the resin layer 1) located on the outer peripheral side of the central core 110.
Since the thermal stress acting on (54) can be dispersed, cracks can be prevented from occurring in the members (especially, secondary spool 131 and resin layer 154) located on the outer peripheral side of central core 110. .

(Eighth Embodiment) In the present embodiment, the resin layer 1 formed between the center core 110 and the secondary coil 130
It is made by paying attention to the point that it is difficult to increase the wall thickness of the 54.

Specifically, the resin layer 154 formed between the center core 110 and the secondary coil 130 is
Filler (in the present embodiment,
(Glass fiber).

The resin layer 1 to which the filler was added
As shown in FIG. 11, the filler is filled in a secondary spool 131 preformed in a cup shape, and thereafter,
It is formed by filling a resin material (potting material).

(Ninth Embodiment) In the ninth embodiment, as shown in FIG. 12, the outer shape of the cross section of the secondary spool 131 is changed from one axial end (spark plug side) to the other end (second housing 152 side). ), The shape gradually changes from a substantially circular shape to a polygonal shape.

Next, the features (effects) of this embodiment will be described.

As described in the first embodiment, the winding of the secondary coil 130 is wound in oblique winding. In the oblique winding, when the winding is wound, the winding is wound. In order to prevent the winding collapse, it is desirable to make the secondary spool 131 have a polygonal outer shape in cross section so that the winding bites into the secondary spool 131 when winding the winding.

However, if the outer shape of the cross section of the secondary spool 131 is a polygon, when the secondary spool 131 is formed by the injection molding method or the like, the resin flow is more disturbed than in the simple outer shape of the circular cross section. Easy to do. When the flow of the resin is disturbed, the orientation of the resin material forming the secondary spool 131 is disturbed, and the mechanical strength of the secondary spool 131 tends to decrease.

On the other hand, the other end of the secondary spool 131 in the axial direction (low pressure side) is more strongly constrained by the second housing 152 than the one end in the axial direction (spark plug side). Stress is easily generated. For this reason, cracks due to thermal stress are likely to occur on the other end side (low pressure side) of the secondary spool 131 in the axial direction.

On the other hand, in the present embodiment, the outer shape of the cross section at one axial end of the secondary spool 131 where cracks (large thermal stress) are likely to occur is substantially circular, while the other end of the secondary spool 131 is axially small. Since the cross-sectional outer shape of is a polygon, it is possible to prevent the secondary spool 131 from cracking while preventing winding collapse.

(Other Embodiments) In the above-described embodiment, the inner peripheral side is the secondary coil and the outer peripheral side is the primary coil. However, the present invention is not limited to this. It is good also as a coil and an inner peripheral side may be a primary coil.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory diagram of skew winding.

FIG. 4 is a sectional view showing characteristics of the ignition coil according to the first embodiment of the present invention.

FIG. 5A is an axial sectional view of a shock-absorbing member (shrinkable tube) according to a second embodiment of the present invention, and FIG. 5B shows characteristics of an ignition coil according to the second embodiment of the present invention. It is sectional drawing.

FIG. 6A is an axial sectional view of a shock-absorbing member (shrinkable tube) according to a third embodiment of the present invention, and FIG. 6B shows characteristics of an ignition coil according to the third embodiment of the present invention. It is sectional drawing.

7A is a cross-sectional view illustrating a feature of an ignition coil according to a fourth embodiment of the present invention, and FIG. 7B is an explanatory diagram illustrating an effect of the ignition coil according to the fourth embodiment of the present invention. is there.

FIG. 8A is a cross-sectional view showing a feature of an ignition coil according to a fifth embodiment of the present invention, and FIG. 8B is an explanatory view for assembling a center core in the ignition coil according to the fifth embodiment of the present invention. It is.

FIG. 9 is a front view of a thin strip showing characteristics of an ignition coil according to a sixth embodiment of the present invention.

FIG. 10 is an explanatory diagram showing characteristics of an ignition coil according to a seventh embodiment of the present invention.

FIG. 11 is a sectional view showing features of an ignition coil according to a seventh embodiment of the present invention.

FIG. 12 is a front view of a secondary spool showing characteristics of an ignition coil according to a seventh embodiment of the present invention.

[Explanation of symbols]

110: central core, 130: secondary coil (inner side coil), 131: secondary spool (winding frame), 154: resin layer.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuhide Kawai 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Atsuyuki Konishi 1-1-1, Showa-cho, Kariya-shi, Aichi Co., Ltd. Inside Denso (72) Inventor Masafuto Sano 1-1-1, Showa-cho, Kariya, Aichi Prefecture Inside Denso Corporation (72) Inventor Shigeya Abe 1-1-1, Showa-cho, Kariya City, Aichi Prefecture Inside Denso Corporation (72 ) Inventor Hideyuki Kato 1-1-1, Showa-cho, Kariya-shi, Aichi, Japan DENSO Corporation (72) Inventor Hidetoshi Nakajima 1-1-1, Showa-cho, Kariya-shi, Aichi, Japan DENSO Corporation (72) Inventor, Mitaka Sato Aichi 1-1-1 Showa-cho, Kariya-shi, Japan Inside DENSO Corporation (72) Inventor Masayasu Adachi 1-1-1, Showa-cho, Kariya-shi, Aichi Co., Ltd. F term in DENSO (reference) 3G019 KB09 KC02 KC04 KC05 KC06

Claims (12)

[Claims] An internal combustion engine ignition coil for supplying a high voltage to an ignition device for an internal combustion engine, comprising: a central core (110) formed in a substantially cylindrical shape; An inner circumferential coil (130) and an outer circumferential coil (120) wound around a tube (11) covering an outer circumferential surface of the central core (110);
1), the inner peripheral coil (130) and the tube (111)
And a resin layer (154) made of a resin material having an electrical insulation property filled in a gap between the central core (110) and the thin plate (1) made of a magnetic material.
10a) in the radial direction of the central core (110). Further, in the resin layer (154), the vicinity of the thin strip plate (110a) having the maximum width dimension is: An ignition coil for an internal combustion engine characterized by being thicker than other parts. 2. An ignition coil for an internal combustion engine for supplying a high voltage to an ignition device of the internal combustion engine, comprising: a central core (110) formed in a substantially cylindrical shape; An inner circumferential coil (130) and an outer circumferential coil (120) wound around a tube, and a tube (11) covering the outer circumferential surface of the central core (110).
1) a spool (131) disposed on the inner circumference side of the inner circumference side coil (130) for winding the winding of the inner circumference side coil (130) formed in a substantially cylindrical shape; A resin layer (154) made of an electrically insulating resin material filled in a gap between the spool (131) and the tube (111); and the central core (110) is made of a thin magnetic material. Strip (1
10a) is laminated in the radial direction of the central core (110), and further, an inner peripheral surface (131a) of the spool (131).
An internal combustion engine characterized in that a groove (131b) extending parallel to the axial direction of the central core (110) is provided in the vicinity of the ribbon (110a) having the largest width dimension. For ignition coil. 3. An ignition coil for an internal combustion engine for supplying a high voltage to an ignition device of the internal combustion engine, comprising: a central core (110) formed in a substantially cylindrical shape; An inner circumferential coil (130) and an outer circumferential coil (120) wound around a tube, and a tube (11) covering the outer circumferential surface of the central core (110).
The center core (110) is a thin plate (1) made of a magnetic material.
10a) is laminated in the radial direction of the center core (110), and the tube (111) is an inner tube (111a) located on the side of the center core (110) and the inner tube. Outer tube (1) covering the outside of (111a)
11b), and the outer tube (111b) is a shrinkable tube whose diameter decreases when heated.
The ignition coil for an internal combustion engine is characterized in that the inner peripheral tube (111a) is a resin tube that becomes molten at a temperature at which the outer peripheral tube (111b) is reduced. 4. An internal combustion engine ignition coil for supplying a high voltage to an ignition device of an internal combustion engine, comprising: a central core (110) formed in a substantially cylindrical shape; The inner core coil (130) and the outer coil (120) wound around the center core (110) are brought into contact with the center core (1).
And a tube (111) covering the outer peripheral surface of the thin plate (1) made of a magnetic material.
10a) is laminated in the radial direction of the central core (110), and at least the outer peripheral side of the tube (111) is filled with a resin material having electrical insulation to form a resin layer (154). Further, the tube (111) has conductivity, and is an ignition coil for an internal combustion engine. 5. An ignition coil for an internal combustion engine for supplying a high voltage to an ignition device for an internal combustion engine, comprising: a central core (110) formed in a substantially cylindrical shape; An inner circumferential coil (130) and an outer circumferential coil (120) wound around a tube, and a tube (11) covering the outer circumferential surface of the central core (110).
1) a resin spool (131) disposed on the inner circumference side of the inner circumference side coil (130) and wound with the winding of the inner circumference side coil (130); and the spool (131). And a resin layer (154) made of a resin material having an electrical insulation property filled in a gap between the tube (111) and the tube (111), and between the resin layer (154) and the spool (131). An ignition coil for an internal combustion engine, comprising an elastic member (154a) that can be elastically deformed. 6. An ignition coil for an internal combustion engine that supplies a high voltage to an ignition device of the internal combustion engine, wherein a central core (10a) formed in a substantially cylindrical shape by laminating thin strips (110a) made of a magnetic material. 110), a cylindrical collar (111c) that covers the outer peripheral surface of the central core (110), and a shrinkable tube that covers the outer peripheral surface of the collar (111c) and has a reduced diameter dimension when heated. (111)
And an inner coil (130) and an outer coil (120) positioned on the outer peripheral side of the shrink tube (111) and wound coaxially with the central core (110). Ignition coil for an internal combustion engine. 7. An ignition coil for an internal combustion engine for supplying a high voltage to an ignition device for an internal combustion engine, wherein a central core (10a) formed in a substantially cylindrical shape by laminating thin strips (110a) made of a magnetic material. 110) and a tube (1) covering the outer peripheral surface side of the central core (110).
11), an inner coil (130) and an outer coil (120), which are located on the outer peripheral side of the tube (111) and are coaxially wound around the central core (110), The thin plate (110a) includes the thin plate (110a).
And a slit extending in the longitudinal direction (110).
b) an ignition coil for an internal combustion engine. 8. An internal combustion engine ignition coil for supplying a high voltage to an ignition device of an internal combustion engine, comprising: a central core (110) formed in a substantially cylindrical shape; and a position outside the central core (110). And an inner peripheral coil (130) and an outer peripheral coil (120) wound coaxially with respect to the center core (110), wherein the center core (110) is a ribbon made of a magnetic material. Board (1
An ignition coil for an internal combustion engine, comprising a plurality of core parts (110c) laminated on each other and joined at longitudinal ends thereof in the axial direction. 9. The thin plate (1) in one core component (110c) of the plurality of core components (110c).
The ignition coil for an internal combustion engine according to claim 8, wherein the lamination direction of 10a) is different from the lamination direction of the thin strip (110a) in another core component (110c). 10. An internal combustion engine ignition coil for supplying a high voltage to an internal combustion engine ignition device, wherein the central core (110) is formed in a substantially cylindrical shape, and is located on an outer peripheral side of the central core (110). And an inner peripheral coil (130) and an outer peripheral coil (120) wound coaxially with the central core (110); the central core (110) and the inner peripheral coil (130).
Resin layer (15)
4), wherein a filler that increases the mechanical strength of the resin layer (154) is added to the resin layer (154). 11. An internal combustion engine ignition coil for supplying a high voltage to an internal combustion engine ignition device, comprising: a primary coil (120) and a secondary coil (130) arranged coaxially; , 130), a central core (110) inserted into the shaft core of the primary coil (120), a substantially cylindrical primary spool (121) formed by resin and wound with a winding of the primary coil (120); A winding of a secondary coil (130) is wound, and a substantially cylindrical secondary spool (131) formed of resin, the center core (110), and both coils (120,
130), which has a cylindrical housing (151) for accommodating the secondary coil (130), and a fixing bracket (152) provided so as to cover one axial end of the housing. The wire is wound in an oblique manner so as to reduce the potential difference between adjacent windings, and the outer shape of the secondary spool (131) at one end in the axial direction is substantially circular. An ignition coil for an internal combustion engine, wherein the outer shape of the cross section at the other end in the direction is a polygon. 12. An internal combustion engine ignition coil for supplying a high voltage to an internal combustion engine ignition device, comprising: a primary coil (120) and a secondary coil (130) arranged coaxially; , 130), a central core (110) inserted into the shaft core of the primary coil (120), a substantially cylindrical primary spool (121) formed by resin and wound with a winding of the primary coil (120); A winding of a secondary coil (130) is wound, and a substantially cylindrical secondary spool (131) formed of resin, the center core (110), and both coils (120,
130), which has a cylindrical housing (151) for accommodating the secondary coil (130), and a fixing bracket (152) provided so as to cover one axial end of the housing. The wire is wound by oblique winding so as to reduce the potential difference between adjacent windings. Further, the outer shape of the cross section of the secondary spool (131) is substantially increased from one axial end to the other end. An ignition coil for an internal combustion engine characterized by gradually changing from a circle to a polygon.