JP6474213B2 - Ignition coil for internal combustion engines - Google Patents

Description

  The present invention relates to an ignition coil that realizes ignition discharge of an internal combustion engine, and more particularly, to an ignition coil that is improved in sealing performance with a plug boot that is in contact with an opening end of a plug hole.

  One ignition coil is arranged for each cylinder of the internal combustion engine, and is fixed to the engine head by a fixing bolt.

  In recent internal combustion engines, a type of ignition coil in which a bent shaft is formed in the plug boot is adopted in accordance with a change in the mounting position of the ignition plug. In this case, the plug boot is partially inserted into the plug hole in a portion parallel to the central axis of the plug hole.

  FIG. 6 shows this ignition coil, and the plug boot 10 is composed of a boot tip 10a inserted into the plug hole 40 and a boot root 10b connected to the case 30 of the ignition coil. . A bending type ignition coil is described in which the bending position 14 is formed in the plug boot 10 and the central axes of the boot tip portion 10a and the boot root portion 10b are inclined (Patent Document 1).

JP 2012-193737 A

  In the ignition coil described in Patent Document 1, when the case of the ignition coil is brought into contact with the cylinder head, an urging force is applied from the inner angle side of the bending axis of the plug boot. There arises a problem of rising and leaving.

  Further, as a recent market demand, it is desired to improve the sealing performance between the plug boot and the opening end of the plug hole to prevent water from entering the plug hole. Therefore, lifting of the outer angle side of the bending shaft at the tip of the boot is against the above requirement.

  The present invention has been made in view of the above problems, and in an ignition coil in which a bending axis is formed in a plug boot, the sealing performance between the plug boot and the opening end of the plug hole is improved, and the plug coil is inserted into the plug hole. An object of the present invention is to provide an ignition coil that prevents water from entering.

In order to achieve the above object, the present invention provides a coil housing that houses a coil assembly , a plug boot that is connected to the coil housing and is provided with a bending portion in advance, and the bending in the coil housing. And a fixing bolt provided on the inner corner side of the portion . The plug boot includes an abutting body having a predetermined thickness, and a dimension along the bending axis direction of the abutting body is set larger on the outer angle side of the bent portion than on the inner angle side .

It is preferable that the largest part and the smallest part of the dimension along the bending axis direction of the contact body are arranged to face each other.

  Preferably, the plug boot is covered with a reinforcing cover at least a part of a portion between the coil housing body and the contact body.

In addition, it is preferable that the upper end surface on the coil container side at the predetermined thickness is substantially perpendicular to the bending axis .

  According to the present invention described above, the axial dimension of the outer abutting portion is larger than the axial dimension of the inner abutting portion, so that even if the ignition coil has a bent shaft formed on the plug boot, the plug boot An ignition coil that prevents the intrusion of water into the plug hole can be realized by improving the sealing property between the plug hole and the open end of the plug hole.

  Further, the plug boot is covered with a reinforcing cover at least a part of the portion between the coil housing body and the contact body, so that the portion exposed from the plug hole of the flexible plug boot is exposed. Strength can be increased.

It is a side view of the ignition coil which concerns on an Example. It is the figure which expanded the A section of FIG. The internal structure of the ignition coil which concerns on an Example is illustrated. It is drawing which shows the ignition coil at the time of floating occurrence. It is the figure which expanded the B section of FIG. 1 is a view showing an ignition coil according to the prior art.

  Hereinafter, the present invention will be described in more detail based on the embodiments shown in FIGS.

  FIG. 1 is a side view of an ignition coil, which is formed from a primary coil in which a primary winding is wound around a primary bobbin, a secondary coil in which a secondary winding is wound around a secondary bobbin, and a silicon steel plate. A coil assembly comprising the iron core thus formed is housed in a resin coil housing 30. A plug boot 10 formed of an elastic member is provided on the bottom surface of the coil housing 30.

  The plug boot 10 is connected to the spark plug 60 on the opposite side to the coil housing portion 30. Further, the plug boot 10 is provided with a bending shaft, and a portion where the bending shaft and the central axis of the plug hole 40 formed in the internal combustion engine are substantially parallel is defined as a boot tip portion 10a.

  The boot tip 10a is inserted into a plug hole 40 formed in the engine block. The plug boot 10 forms an abutment body 12 that abuts against the open end 42 of the plug hole 40. Here, the abutment body 12 is formed in an annular shape along the annular plug hole opening end 42, and the radial direction of the plug boot 10 with respect to the boot tip 10a. The shape is large. The contact body 12 includes an outer contact portion 12a formed on the outer angle side of the bending shaft and an inner contact portion 12b formed on the inner angle side of the bending shaft.

Here, if the size of the axial component of the central axis of the plug hole 40 and the axial dimension, axial dimension L ₁ of the outer abutment portion 12a, the axial dimension of the inner contact portion 12b L ₂ It is formed to be larger.

  The plug boot 10 includes a resin reinforcing cover 20 at a portion between the coil housing body 30 and the contact body 12. The reinforcing cover 20 has one end 20a in contact with the coil housing 30 and the other end 20b in contact with the contact body 12.

Incidentally, the coil container 30 is provided with a fixing bolt 32, the coil container 30 by given a biasing force F ₀ from the inner angle side of the bent shaft is fixed to the engine head 50 by the fixing bolt 32 .

  Next, FIG. 2 is an enlarged view of part A shown in FIG.

  The abutment body 12 has a sealing property because an annular seal surface constituting the abutment body 12 is disposed on the bottom side of the plug hole 40 with respect to an opening surface constituting the plug hole opening end 42. It is increasing. The contact body 12 has an annular shape whose axial dimension gradually increases from the inner contact portion 12b toward the outer contact portion 12a.

  Next, in FIG. 3, the outer contact portion 12 a and the inner contact portion 12 b have a shape protruding from the contact body 12 toward the plug hole 40. When the plug boot 10 is inserted into the plug hole 40, the tip of the abutment body 12 abuts in an annular groove provided at the plug hole opening end 42.

  The reinforcing cover 20 covers the entire outer periphery of the boot root portion 10b from the bent portion 14 where the bending axis of the plug boot 10 is refracted to the connection side of the coil housing 30, and the contact body. 12 and the coil housing body 30 to prevent the contact body 12 from floating from the plug hole opening end 42.

  A high voltage tower 34 is formed on the bottom surface of the coil housing 30 and the high voltage tower 34 is fitted and connected to the boot root 10b. A spring 70 made of a conductor is built in the plug boot 10. A high voltage generated by the coil assembly is supplied to the spark plug 60 through the spring 70.

In this embodiment, failure or when the biasing force F ₁ is smaller than the request by the fixing bolts 32 as shown in FIG. 4, the vibration during operation of the internal combustion engine, the direction in which the plug boot 10 comes out from the plug hole 40 Power is generated. Then, the contact body 12 is lifted from the plug hole opening end 42.

In the case of the present embodiment, since the fixing bolt 32 that applies the urging force F ₀ to the coil housing 30 is provided on the inner angle side of the bending shaft, the outer angle side of the bending shaft is separated from the fixing bolt 32. The distance gets longer. Therefore, the urging force acting on the outer contact portion 12a is smaller than the urging force acting on the inner contact portion 12b.

  Then, as shown in FIG. 5 in which the portion B shown in FIG. 4 is enlarged, the outer contact portion 12a floats larger than the inner contact portion 12b. However, since the axial dimension of the outer abutting portion 12a is larger than the axial dimension of the inner abutting portion 12b, the ring-shaped sealing surface constituting the abutting body 12 has the plug hole opening end 42. A state in which the plug hole 40 is disposed on the deep bottom side from the opening surface to be configured is maintained. That is, the tip of the outer abutting portion 12a shown in FIG. 3 does not separate from the plug hole opening end.

As described above, according to this embodiment, the plug boot 10 forms the abutting body 12 that abuts against the opening end 42 of the plug hole 40, and the abutting body 12 includes the outer abutting portion 12a. the axial dimension L ₁ of the inner contact portion 12b by a larger configuration than the axial dimension L ₂ of the even phenomenon abutment body 12 from floating occurs, the outer abutment portion 12a is the It can be prevented that the plug hole is completely separated from the opening end 42 of the plug hole.

  Therefore, the sealing property between the contact body 12 and the plug hole opening end 42 is maintained, and a defect caused by water entering the plug hole 40 can be prevented.

  On the other hand, by providing the reinforcing cover 20 at a portion between the coil housing body 30 and the contact body 12 of the plug boot 10, the strength of the boot root portion 10b exposed from the plug hole 40 is increased. be able to.

  Further, the reinforcing cover 20 can improve the sealing performance of the contact body 12 because the other end portion 20b presses the contact body 12.

As described above, the embodiment of the present invention has been described in detail. However, the plug boot 10 may be configured such that at least a part of a portion substantially parallel to the central axis of the plug hole 40 is inserted into the plug hole 40. . Further, the axial dimension L ₁ of the outer contact portion 12a may be said axial dimension is larger construction than any portion of the abutting member 12. Alternatively, the axial dimension L ₁ of the outer contact portion 12a may be larger than the arrangement only the axial dimension L ₂ of the inner contact portion 12b.

The length of the axial dimension L ₁ of the outer abutment portion 12a is to be changed according to the angle of the bent shaft provided in the plug boot 10. That, as the angle of the bending axis is increased, the value of the force F ₀ with given of the outer abutment portion 12a by the fixing bolt 32 is reduced, the axial dimension of the outer abutment portion 12a L ₁ This is because it is necessary to lengthen the length.

The fixing bolt 32 of this embodiment is more effective for the configuration in which the urging force F ₀ is applied from the inner angle side of the bending shaft of the plug boot 10. the bent when fed a biasing force F ₀ from the inner angle side of the bent axis of the plug boot 10 with respect to the inner angle side of the buoyant force of the bending axis when fed a biasing force F ₀ from the exterior angle side of the bent shaft This is because the levitation force on the outer angle side of the shaft becomes smaller.

  By the way, when the plug hole opening end 42 is a flat surface, the outer contact portion 12a and the inner contact portion 12b are configured to enhance the sealing performance by contact between the plug hole opening end 42 and the surfaces, The contact surface between the outer contact portion 12a and the plug hole opening end 42 is adapted to have a larger area than the contact surface between the inner contact portion 12b and the plug hole opening end 42. You can also.

  The reinforcing cover 20 may cover at least a part of the portion of the plug boot 10 exposed from the plug hole 40. The reinforcing cover 20 may be configured such that the one end portion 20a is fixed by the boot root portion 10b and the other end portion 20b is pressed against the contact body 12.

10: Plug boots
10a: Boot tip
10b: Boot base
12: Contact body
12a: Outer contact part
12b: Inside contact part
14: Bending part
20: Reinforcement cover
20a: One end
20b: the other end
30: Coil container
32: Fixing bolt
34: High-pressure tower
40: Plug hole
42: Plug hole open end
50: Engine head

Claims (4)

A coil housing for housing the coil assembly ;
A plug boot connected to the coil container and provided with a bent portion in advance ;
In the coil housing body, a fixing bolt provided on the inner angle side of the bent portion,
An ignition coil for an internal combustion engine comprising:
The plug boot includes a contact body having a predetermined thickness,
An ignition coil for an internal combustion engine , wherein a dimension along the bending axis direction of the contact body is set larger on an outer angle side of the bent portion than on an inner angle side . 2. The ignition coil for an internal combustion engine according to claim 1, wherein a dimension along the bending axis direction of the contact body is arranged such that a largest part and a smallest part face each other . The plug boot, said that the coil container at least a part of the site to be between the abutment body is covered with a reinforcement cover, ignition coil for an internal combustion engine according to claim 1 or 2. The ignition coil for an internal combustion engine according to any one of claims 1 to 3, wherein an upper end surface on the coil housing body side at the predetermined thickness is substantially perpendicular to the bending axis .

Images