JPH02896Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an ignition coil for an engine.

Conventionally, as this type of ignition coil, a single coil is attached to the outer periphery of an iron core that penetrates an electrically insulating case that is shaped like a cylinder with a bottom.
It is known that a secondary coil and a secondary coil are sequentially wound, and a case is filled with a thermosetting synthetic resin and hardened.

The above-mentioned ignition coil has a problem in that the output voltage of the secondary coil is not constant unless the primary coil is correctly positioned in the axial direction with respect to the secondary coil.

Furthermore, if the iron core is not securely fixed to the case when filling with synthetic resin, the core may become misaligned, and it may be necessary to apply a synthetic resin leak-proof seal to the iron core. be.

The object of the present invention is to provide the ignition coil that can eliminate the above-mentioned problems, and is provided with an electrically insulating cylindrical case with a bottom. A core of a hollow bobbin wound with a secondary coil is fitted around the outer periphery of the cylinder, leaving an annular space, and the inner part of the core is formed on the bottom side of the cylinder. A protrusion is provided on the circumferential surface of the cylindrical portion, and the protrusion fits into the cylindrical portion and comes into contact with one end of the primary coil disposed in the annular space to position the primary coil in the axial direction. It is characterized by being filled with thermosetting synthetic resin and hardened.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, the interior of the electrically insulating case 1, which is formed from synthetic resin or the like and has a cylindrical shape with a bottom, is approximately circular due to the partition walls 2. It is divided into a first chamber _R1 which forms a square shape and a second chamber _{R2 which} has a rectangular shape. The first chamber R1 accommodates the ignition coil unit _C , and the second chamber R1 accommodates the ignition coil unit C.
A transistor type igniter I is housed in _R2 . The first and second chambers R ₁ and R ₂ are filled with a thermosetting synthetic resin 3 having substantially the same coefficient of thermal expansion as the igniter I, and thereby the ignition coil unit C is placed in the first chamber R ₁ . Further, an igniter I is fixed in the second chamber _R2 , and an ignition coil Ic is configured.

As the synthetic resin 3, for example, a bisphenol type epoxy resin is applicable, and as a curing agent, an organic acid anhydride is used. By using such a synthetic resin 3, even if the igniter I expands thermally due to the heat generated by the power transistor used therein, cracks between the igniter I and the synthetic resin 3 can be prevented.

Ignition coil unit C is constructed as follows. That is, in order to hold the iron core 5 penetrating through the first chamber R ₁ on the inner surface of the bottom 4 of the case 1 and therefore the first chamber R ₁ , a cylindrical portion 8 that closely contacts the outer peripheral surface of the iron core 5 is integrated with the bottom 4 . is formed. The cylindrical portion 8 extends from the bottom 4 of the first chamber _R1 to the opening 11, and a primary coil 6 and a secondary coil 7 are sequentially wound around the outer periphery of the cylindrical portion 8. The iron core 5 is made by laminating a plurality of silicon steel plates, and the connecting portions 9 and 10 at both ends thereof protrude from the opening 11 of the first chamber _R1 and the outer surface of the bottom portion 4.

The secondary coil 7 is wound around a winding core 13 of a synthetic resin hollow bobbin 12, and the winding core 13 is wound around a cylindrical portion 8.
It is fitted with an annular space around the outer periphery. Flange portion 1 located on the bottom 4 side of the hollow bobbin 12
4 comes into contact with a plurality of protrusions 15 protruding from the inner surface of the bottom portion 4, thereby separating the flange portion 14 from the inner surface of the bottom portion 4, thereby preventing creeping discharge to be described later.

Further, the primary coil 6 is fitted into the cylindrical portion 8 and disposed in the annular space. Bottom part 4 of core 13
An inward flange-like protrusion 16 is provided on the inner peripheral surface of the side opening.
is formed, and by bringing one end of the primary coil 6 into contact with the protrusion 16, the primary coil 6 is correctly positioned in the axial direction with respect to the secondary coil 7.

As shown in FIG. 4, the opening 11 of the first chamber _R1
An input terminal insertion hole 17 that opens in the same direction as the opening 11 is formed in the inner peripheral surface. As clearly shown in FIG. 5, the input terminal 18 includes a plate-shaped insertion part 20 into which a short synthetic resin cylinder 19 is fitted, a hook-shaped base end part 21 protruding from one side of its base end, and a hook-shaped base end part 21 on the opposite side. It has a connecting portion 22 that protrudes from the side. The base end portion 21 is inserted into the terminal insertion hole 17, while the connecting portion 2
2 is brought into contact with the end surface of the flange portion 23 of the bobbin 12. The connection part 22 has primary and secondary coils 6, 7.
The input side terminals 6a, 7a of the igniter I are connected to the input side terminal Ia of the igniter I through the notch 2a of the partition wall 2 by solder s.

As shown in Figures 1, 3 and 6, the first chamber R ₁
A connecting plate 25 having a cut-and-raised claw 24 is attached to the connecting portion 9 of the iron core 5 protruding from the opening 11 of the rivet 2.
It is fixed by 6. Ground side terminal 6 of igniter I passed through primary coil 6 and notch 2b of bulkhead 2
b and Ib are guided to the connection plate 25 and are clamped to the connection plate 25 by the cut and raised claws 24. As a result, both ground side terminals 6b and Ib are connected to the iron core 5 via the connection plate 25. When the primary coil 6 is fitted to the outer periphery of the iron core 5, the cut-and-raise claws 24 are laid down to avoid interference between the primary coil 6 and the cut-and-raise claws 24.

As shown in FIGS. 1 to 3, a tubular bulge 28 is formed in a part of the peripheral wall 27 of the first chamber _R1 , and extends from the opening 11 to the intermediate portion along the generatrix direction. Also, a first chamber is connected to the bottom part 29 of the bulging part 28.
On the outer circumferential surface of R ₁ , a high-voltage cord connecting pipe 30 is extended in the same direction as the bulging part 28 , and the tip of the connecting pipe 30 is a predetermined length from the outer surface of the bottom 4 of the first chamber R _{1 .} It stands out. As shown in Figure 7, bobbin 1
A terminal holding member 31 made of synthetic resin is installed between the pair of flange portions 14 and 23 of No. 2, and a pin-shaped output terminal 33 is penetrated and held by a projecting piece 32 protruding from the intermediate portion of the member 31. Ru. The output side terminal 7b of the secondary coil 7 passes through the notch 34 of the terminal holding member 31 and the through hole 35 at the base end of the protruding piece 32 to the output terminal 33.
It is connected to the proximal end side by solder s.

When the secondary coil 7 is disposed in the first chamber R ₁ , the output terminal 33 passes through the bulge 28 , passes through the through hole 36 in the bottom 29 , and protrudes into the connecting pipe portion 30 . A high-voltage cord 37 is inserted into the connecting tube section 30, and the output terminal 33 is inserted into the conductor section 38 to connect both 33 and 38. Further, the outer circumferential surface of the covering portion 39 of the high voltage cord 37 and the inner circumferential surface of the connecting tube portion 30 are bonded together with an adhesive.

In this case, since the connecting pipe portion 30 extends on the outer peripheral surface of the first chamber _R1 along the generatrix direction,
In order to form the connecting tube section 30 sufficiently long to ensure adhesive strength of the high voltage cord 37 to the connecting tube section 30, the overlapping length of the connecting tube section 30 with the outer peripheral surface of the first chamber _R1 is set to be sufficiently long. Therefore, the length of the tube portion 30 protruding from the bottom outer surface of the first chamber _R1 can be short, and the whole can be made smaller.

After each component is arranged in the first chamber _R1 as described above, the synthetic resin 3 is filled in the first chamber _R1 and hardened.

In this case, the iron core 5 is inserted into the case 1 through the cylindrical portion 8.
Since it is securely fixed, there is no possibility of displacement. Further, since the cylindrical portion 8 is integrated with the bottom portion 4, the synthetic resin 3 will not leak, and therefore no sealing means is required. Further, with the primary coil 6 properly positioned relative to the secondary coil 7, the coils 6 and 7 can be embedded in the synthetic resin 3.

A series of minute gaps are created between the hardened resin 3, the bobbin 12, the protrusion 15, and the inner surface of the first chamber _R1 , but since the minute gaps are extended by the protrusion 15, two or more locations on the secondary coil 7 are formed. Even if a leakage portion occurs in the leakage portion, the distance between the leakage portions through the minute gap becomes longer, thereby making it possible to prevent the occurrence of creeping discharge between the two leakage portions.

In addition, the base end 21 of the input terminal 18 is inserted into the terminal insertion hole 1.
7, a part of the peripheral wall of the terminal insertion hole 17 becomes a partition wall for the secondary coil 7, and if a leak occurs in the secondary coil 7, the synthetic resin 3 and the inner surface of the first chamber _R1 Since the distance between the leak portion and the base end portion 21 becomes longer through the minute gap created therebetween, generation of creeping discharge between the leak portion and the base end portion 21 can be prevented.

Next, the mounting structure of the ignition coil Ic will be explained with reference to FIGS. 8 to 11.

U-shaped notches 42 and 43 are formed in the pair of yokes 40 and 41, respectively.
The connecting portions 9 and 10 of the iron core 5 and the iron core 5 are fitted into the recesses and recesses by press-fitting from a direction perpendicular to the center line of the iron core 5. In this case, a retaining recess 44a and a retaining convex portion 44b are formed on both side press-fit surfaces of each connecting portion 9, 10 and the press-fit surface of each notch 42, 43 opposing thereto. The engagement of the retaining means 44 with the retaining convex portion 44b ensures that each yoke 40, 41 is prevented from being withdrawn in the direction of the center line of the iron core 5. Further, as clearly shown in FIG. 9, a protrusion 45 is protruded from the outer surface of the bottom 4 of the first chamber R ₁ in the vicinity of the connecting portion 10 , and one yoke 41 abuts on the protrusion 45 .

Furthermore, a press-fitting surface of the tip end of each connecting portion 9, 10,
A pin hole 46 consisting of recesses 46a and 46b formed in the illustrated example is formed in the press-fit surface of each of the yokes 40 and 41 facing thereto, and a spring pin 47 is press-fitted into each pin hole 46. Ru. Due to the wedge action of these spring pins 47, the pressure contact force between the concave and convex fitting portions of the retaining recess 44a and the retaining convex portion 44b increases, so that both connecting portions 9, 10 of the iron core 5
and the connection structure between both yokes 40 and 41 becomes stronger,
The yokes 40 and 41 are prevented from coming off in a direction perpendicular to the direction of the center line of the iron core 5.

The mounting base 48 includes a flat plate part 49 and a pair of pillar parts 50 and 51 erected on one side of the flat plate part 49, so that the protruding part 45 of the ignition coil Ic and the flat plate part 49 face each other, and the outer peripheral surface of the case 1 is made into a flat plate. Each yoke 40, 41 is fixed to each column part 50, 51 with a bolt 52 while in contact with part 49. As a result, the surface 41a of one yoke 41 facing the flat plate part 49 comes into contact with the protrusion 45, and the case 1 is held between the flat plate part 49 and one yoke 41, so that both ignition coils Ic External locking from the yokes 40 and 41 is ensured.

As described above, according to the present invention, by simply arranging the primary coil in the annular space, it is possible to correctly position the primary coil in the axial direction with respect to the secondary coil using the protrusion on the inner peripheral surface of the winding core. This allows the output voltage of the secondary coil to be always constant.

Further, it is possible to provide an ignition coil in which the iron core and the primary and secondary coils are firmly held against the case.

Furthermore, since the case and the cylindrical portion holding the core are integrated, there is no need for sealing means for the core when filling the synthetic resin, and an ignition coil with good filling workability can be provided.

Moreover, since the cylindrical portion has the function of holding the iron core and the function of bobbing the primary coil, the structure can be simplified.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a perspective view of the entire ignition coil, FIG. 2 is a plan view of the entire ignition coil, and FIG. 3 is a sectional view taken along the line shown in FIG. 2.
Figure 4 is a cross-sectional view taken along the line shown in Figure 2, Figure 5 is a perspective view of the input terminal, Figure 6 is a cross-sectional view taken along the line taken from Figure 3, Figure 7 is a perspective view of the secondary coil, and Figure 8 is the ignition. 9 is a perspective view of the ignition coil seen from the bottom, 10 is a side view of the ignition coil installed, and 11 is 10.
It is a view taken along arrow XI. 1...Case, 3...Synthetic resin, 4...Bottom,
5...Iron core, 6...Primary coil, 7...Secondary coil, 8...Cylinder part, 12...Hollow bobbin, 13...
Core, 16... protrusion.

Claims (1)

[Scope of utility model registration request] A cylindrical electrically insulating case 1 with a bottom, the case 1
A cylindrical portion 8 is integrally formed and extends from the bottom 4 of the case 1 to the opening 11 in close contact with the outer peripheral surface of the iron core 5 passing through the cylindrical portion 8.
The winding core 13 of the hollow bobbin 12 wound with the above-mentioned hollow bobbin 12 is fitted with an annular space therebetween. A protrusion 16 is provided which contacts one end of the primary coil 6 arranged to position the primary coil 6 in the axial direction, and the case 1 is filled with a thermosetting synthetic resin 3 and hardened. An ignition coil for engines characterized by: