JPH04370685A - Plug cap device - Google Patents

Abstract

PURPOSE:To prevent a spark plug from remaining out of arc discharging in a plug cap device used in a DCHC type gasoline engine, etc. CONSTITUTION:An ignition cable 7 termination part, a cable side terminal 8 in con with this part, a discharge tube unit, and a plug side terminal for connection of a spark plug are accommodated in the long cylindrical plug cap body 2. The inside circumferentrial surface of this cap body 2 is adhered by an adhesive 16 to the peripheral surface of the ignition cable 7 in their whole mating surfaces over the whole circumference. Even though corona discharge is generated in the neighborhood of each terminal when engine is operating, the inside circumferential surface of the cap body 2 mating with the peripheral surface of the ignition cable 7 remains not exposed to the air layer, and no attachment will be made with Al salt or Ca salt which is deliquescent, electrolytic, and electroconductive likely initiated by corona discharge. Thus a path for leakage of energy can be shut.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a plug cap device incorporating a discharge tube unit for connecting a spark plug and an ignition cable as a high-voltage electric wire in a DOHC (double overhead camshaft) type gasoline engine, etc. .

0002

2. Description of the Related Art In recent years, in order to prevent spark plugs from smoldering, a discharge tube unit has been incorporated into a plug cap device to increase the discharge voltage.

As this type of plug cap device, DO
There is a plug cap device used in HC type gasoline engines.Since the plug hole in the engine is deep, there is a plug cap body made of synthetic resin formed into a relatively long cylinder, and a plug cap device that is inserted from one end of the plug cap body. the ignition cable, the cable-side connection terminal connected to the end of the ignition cable, the plug-side connection terminal for connecting the spark plug located at the other end of the plug cap body, and the cable-side connection terminal. It mainly consisted of a discharge tube unit installed between the plug-side connection terminals. Usually, a rain cover made of rubber or the like is fitted to one end of the plug cap body, that is, the upper end, and the ignition cable is cut through it, and a waterproof rubber rain cover is fitted to the other end, that is, the lower end of the plug cap body. The cap is fitted.

When in use, the plug cap body is inserted into the plug hole of the engine from the plug side connection terminal side, and the plug side connection terminal is connected to the spark plug.
The opening edge of the plug hole was configured to be closed with a rain cover.

[0005]

[Problems to be Solved by the Invention] However, in this type of plug cap device, the surface of the plug cap body, especially the inner circumferential surface and outer circumferential surface of the portion corresponding to the cable side connection terminal and the plug side connection terminal position. In addition, aluminum salts and calcium salts were deposited as deposits. This is because when the spark plug's discharge voltage becomes high, corona discharge occurs in the air near the connection terminal, and this corona discharge causes the aluminum and calcium contained in the material of the plug cap body to combine with nitrogen, etc. in the air. This is thought to be because it adheres to the surface. In other words, since the plug cap device is used under high temperatures due to heat from the engine, the flame retardance of the plug cap body is essential, and to ensure this, aluminum hydroxide is filled as an additive. However, eliminating the filling of aluminum hydroxide or reducing the amount below the required amount poses a problem from the viewpoint of ensuring flame retardancy.

[0006] Since the aluminum salt and calcium salt are electrolytes and deliquescent, they absorb moisture in the air and eventually become conductive substances. As shown in FIG. 4, a conductive substance generated on the inner circumferential surface of the plug cap 101 corresponding to the cable-side connection terminal is caused by surface tension on the opposing surface between the inner circumferential surface of the plug cap body 101 and the inner circumferential surface of the ignition cable 102. The air vent hole 104 of the rain cover 103 and the air vent hole 104 of the rain cover 103 and the conductive material generated on the entire outer peripheral surface corresponding to the cable side connection terminal of the plug cap body 101 rise through the gap 105 between the rain cover 103 and the plug cap body. The problem is that electricity flows through the contact surface with 101 and further flows into the nearest ground body, resulting in energy leaking to the outside, resulting in insufficient voltage to discharge the spark plug, resulting in a non-discharge state of the spark plug. was there.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a plug cap device that prevents energy leakage and prevents non-discharge of a spark plug.

[0008]

[Means for Solving the Problems] A first technical means for achieving the above object is to provide an ignition cable terminal portion inserted from one longitudinal end side into a vertically long cylindrical plug cap body. In a plug cap device in which a discharge tube unit is incorporated between a connected cable side connection terminal and a plug side connection terminal for connecting a spark plug arranged on the other end side, the inner periphery of the plug cap body A part or all of the opposing surfaces of the surface and the outer peripheral surface of the ignition cable are bonded to each other with an adhesive over the entire circumferential direction.

[0009] A second technical means is to provide a cable-side connection terminal connected to an ignition cable end inserted into a vertically long cylindrical plug cap body from one end in the longitudinal direction, and a cable-side connection terminal connected to an ignition cable terminal at the other end. In a plug cap device in which a discharge tube unit is incorporated between a plug-side connection terminal for connecting a spark plug arranged on the side, the synthetic resin portion of the plug cap body corresponds to at least the position of the cable-side connection terminal. or the part corresponding to the plug side connection terminal position, and either the outer peripheral surface side or the inner peripheral surface side of the corresponding part, or both sides thereof, as a rubber or filler material. The main feature is that a surface layer is formed of an organic material other than rubber that does not contain aluminum or calcium as an element.

0010

[Operation] According to the first invention, even if deposits of aluminum salt or calcium salt are generated on the outer circumference side or inner circumference side of the plug cap body due to corona discharge, the inner circumference surface of the plug cap body and the outer circumference of the ignition cable Since the opposing surfaces are bonded to each other with adhesive over the entire circumferential direction, the path of energy leakage to the outside of the plug cap body is cut off, preventing energy leakage to the outside and preventing ignition. This prevents the plug from not discharging.

According to the second invention, rubber, aluminum, or calcium is applied to the outer or inner peripheral surface of the synthetic resin portion of the plug cap body in the portion corresponding to each connection terminal where corona discharge is likely to occur. Since the surface layer is made of an organic material other than rubber that does not contain any elements, the surface of the synthetic resin part of the plug cap body covered by the surface layer is not affected by corona discharge and is free from aluminum salts and calcium salts. It does not occur as a deposit. Furthermore, the surface layer covering the synthetic resin portion of the plug cap body does not generate aluminum salt or calcium salt as deposits even by corona discharge. Therefore, the formation of deposits of aluminum salts and calcium salts on the inner and outer surfaces of the plug cap body can be prevented, and the formation of conductive substances on the inner and outer surfaces of the plug cap body is prevented, thereby preventing energy leakage to the outside. This can prevent the spark plug from discharging.

0012

[Embodiments] Hereinafter, embodiments of the first invention will be explained based on the drawings. In FIGS. 1 and 2, a plug cap device 1 is constructed of a plug cap made of synthetic resin and formed into a longitudinally cylindrical shape, as in the prior art. The plug cap body 2 includes a main body 2, and a rubber cap 3 is fitted onto one end, ie, the lower end, of the plug cap main body 2 from the inside and outside. Also, the plug cap body 2
At the other end, that is, at the upper end, a rain cover 4 made of rubber or the like is fitted over the outside as in the conventional case.
An air vent hole 5 is formed in the side part of.

The plug cap main body 2 has a two-part structure that can be disassembled into an upper cable side main body 2a and a lower plug side main body 2b, and the cable side main body 2a and the lower plug side main body 2b are formed on one side. The engaging claws 2c are inserted into the engaging grooves 2a formed on the other side from the axial direction, and then rotated in the circumferential direction to be connected by a twist locking method in which the engaging claws 2c are locked in a manner that prevents them from coming out. There is.

The end of the ignition cable 7 is connected to the rain cover 4.
It is made to penetrate into the rain cover 4 from the side part, and
The plug cap body 2 is inserted into the plug cap body 2 from the upper end toward the lower end, and a cable side connection terminal 8 is caulked to a terminal at a midway point inside the cable side body 2a. Further, inside the plug side main body 2b, a plug side connection terminal 9, a spring 10, a discharge tube unit 11, and a spring 12 are arranged in order from the bottom. 12 is impedance element 1
4 is pushed upward to bring it into reliable contact with the cable-side connection terminal 8, and to establish electrical continuity between the electrode on the discharge tube unit 11 side and the impedance element 14. Further, the lower spring 10 similarly establishes conduction between the electrode on the discharge tube unit 11 side and the plug side connection terminal 9. 15 is O
The ring prevents moisture from entering from the connection between the cable side main body 2a and the plug side main body 2b.

The inner peripheral surface of the plug cap main body 2 and the outer peripheral surface of the ignition cable 7, which face each other, are bonded to each other in the circumferential direction with an adhesive 16. adhesive 16
For example, S-Lock 8501, a product of Hikiei Boeki Co., Ltd., which is used to bond the rain cover 4 and the penetrating portion of the ignition cable 7, may be used.

The embodiment of the first invention is constructed as described above, and when the plug cap device 1 is attached to a spark plug and used, when the engine is driven by the activation of the spark plug, the air near each connection terminal 8, 9 is removed. Even if a corona discharge occurs inside the plug cap body 2, the inner circumferential surface of the plug cap body 2 is filled with the adhesive 16 and bonded between the facing surfaces of the inner circumferential surface of the plug cap body 20 and the outer circumferential surface of the ignition cable 7. Since it is not exposed to an air layer, corona discharge on the inner peripheral surface side of the plug cap main body 2 at this position can be prevented, and no aluminum salt or calcium salt is generated. Therefore, even if aluminum salt or calcium salt is generated on the outer circumferential surface side or the inner circumferential surface side of other parts of the plug cap body 2, the conductive substance that continues from the inner circumferential surface side to the outer circumferential surface side of the plug cap body 2 This effectively prevents the flow of electricity to the outside through the air vent hole of the rain cover 4 and the contact surface between the rain cover 4 and the plug cap body 2. This prevents energy from leaking to the outside, and the spark plug reaches sufficient voltage for discharge, ensuring a good discharge condition.

[0017] In the above embodiment, a structure is shown in which the inner circumferential surface of the plug cap body 2 and the outer circumferential surface of the ignition cable 7 are bonded over the entire opposing surface with the adhesive 16.
Even in the case of a structure in which the adhesive is bonded only partially over the entire circumferential direction, the path of energy leakage can be similarly cut off.

FIG. 3 shows an embodiment according to the second invention, and since the overall configuration is substantially the same as the embodiment of the first invention described above, the same reference numerals are given and the explanation will be omitted.

The outer periphery of the discharge tube unit 11 incorporated into the plug cap body 2 is closely covered with protective covers 18a and 18b made of oil-impregnated rubber, which ensure electrical insulation and sealing properties. Discharge tube unit 1
1 within the plug cap body 2, and plays a role of protecting the discharge tube unit 11 with its elastic force. 19 is an impedance element 14 and a spring 12
20 is a plug-side connection terminal 9.
This is a fixed member that restricts the movement of the spring 10.

[0020] Then, an insulating cover body 21 as a cylindrical insulating surface layer made of silicone rubber covers the entire outer peripheral surface exposed between the rubber cap 3 and rain cover 4 (not shown) of the plug cap body 2. It is tightly fitted. That is, the inner diameter of the insulating cover body 21 is formed to be slightly smaller than the outer diameter on the side of the plug cap main body 2, and the insulating cover body 21 is made into a tight fit due to elastic deformation.

The embodiment of the second invention is constructed as described above, and as shown in FIG.
The inner circumferential surface of the rubber cap 3 is crimped to provide a waterproof function. Even if corona discharge occurs in the air near each connection terminal 8, 9 when the engine is driven by the activation of the spark plug 23,
Since the outer circumferential surface of the plug cap body 2 is tightly covered with the insulating cover body 21, the outer circumferential surface of the plug cap body 2 is not exposed to an air layer, and corona discharge on the outer circumferential surface side of the plug cap body 2 occurs. This prevents the generation of aluminum salts and calcium salts. In addition, the insulating cover body 21
is exposed to an air layer, but corona discharge does not generate any conductive deposits on its surface. On the other hand, the inner peripheral surface of the plug cap body 2 is exposed to an air layer.
Although there is a risk that aluminum salts and calcium salts may be generated, conductive substances are not formed on the outer peripheral surface of the plug cap body 2, so conductive substances are not formed on both the inner and outer peripheral surfaces of the plug cap body 2. As described above, the flow of electricity to the outside through the air vent hole 5 of the rain cover 4 (not shown) and the contact surface between the rain cover 4 and the plug cap body 2 can be effectively prevented, and therefore the energy is prevented from flowing to the outside. This prevents leakage to the spark plug 23, provides sufficient voltage for discharge, and ensures a good discharge condition. Furthermore, since silicone rubber is used as the insulating cover body 21, it also has the advantage of being excellent in heat resistance. Furthermore, the sealing properties and electrical insulation properties of the divided portions of the plug cap body 2 can be improved by the insulating cover body 21, and the withstand voltage can also be improved.

Although this embodiment shows a structure in which the outer circumferential surface of the plug cap body 2 is covered with the insulating cover body 21, a structure may also be adopted in which the inner circumferential surface is covered. A structure that covers both may be used.

It is most preferable to cover both the inside and outside surfaces with the insulating cover body 21, but each connection terminal 8, 9
If the structure is such that at least one of the parts corresponding to the position and either the outer peripheral surface side or the inner peripheral surface side of the corresponding part is covered with the insulating cover body 21, the generation of aluminum salts and calcium salts can be prevented. This can be effectively prevented, and the energy leakage prevention effect can be fully demonstrated.

Furthermore, although a structure is shown in which rubber is used as the insulating cover body 21, an organic material other than rubber (for example, filler-free epoxy resin) having an insulating property that does not contain aluminum or calcium as an element may be used as a filler. The insulating cover body 21 may be formed by coating the inner circumferential surface or outer circumferential surface of the plug cap body 2. In this case, since the material to be coated does not contain aluminum or calcium as an element, there is no risk of generation of aluminum salts or calcium salts.

Further, although the entire plug cap body 2 is made of synthetic resin and its surface is separately covered with an insulating cover body 21 as a surface layer, the plug cap body 2 is made of a composite material by two-color molding or the like. 2, and a surface layer portion made of rubber or the organic material may be integrally formed on the surface side of the synthetic resin portion.

Furthermore, the structure of the plug cap device may be a combination of the first invention and the second invention, and energy leakage can be more reliably prevented.

[0027]

According to the plug cap device according to the first aspect of the invention, a part or all of the opposing surfaces of the inner peripheral surface of the plug cap body and the outer peripheral surface of the ignition cable are bonded to each other with an adhesive over the entire circumferential direction. Therefore, the path of leakage of discharge energy to the outside of the plug cap body can be cut off, and energy leakage to the outside can be prevented.
It is possible to prevent the spark plug from discharging.

Further, according to the plug cap device according to the second aspect of the invention, at least the outer circumferential surface side or the inner circumferential surface of either the cable side connecting terminal or the portion corresponding to the plug side connecting terminal of the synthetic resin portion of the plug cap main body. Since a surface layer made of rubber or an organic material other than rubber that does not contain aluminum or calcium as an element as a filler is provided on one or both sides of the plug cap body, aluminum salt on the surface side of the plug cap body The generation of calcium salts can be effectively prevented.
Since no conductive material is formed here, it is possible to prevent the flow of electricity between the inner and outer surfaces of the plug cap body and even to the nearest grounding body, thus preventing energy leakage to the outside. , it is possible to prevent non-discharge of the spark plug.

[Brief explanation of drawings]

FIG. 1 is a sectional side view of a main part showing an embodiment according to a first invention.

FIG. 2 is a cross-sectional side view of the entire device.

FIG. 3 is a cross-sectional side view of essential parts showing an embodiment according to the second invention.

FIG. 4 is a partially sectional side view showing a conventional example.

[Explanation of symbols]

1 Plug cap device 2 Plug cap body 7 Ignition cable 8 Cable side connection terminal 9 Plug side connection terminal 11 Discharge tube unit 16 Adhesive 21 Insulation cover body 23 Spark plug

Claims (2)

[Claims] [Claim 1] Inside the vertically long cylindrical plug cap body,
A discharge tube unit is installed between a cable-side connection terminal connected to an ignition cable terminal inserted from one end in the longitudinal direction and a plug-side connection terminal for connecting a spark plug arranged at the other end. The plug cap device is characterized in that a part or all of the opposing surfaces between the inner circumferential surface of the plug cap main body and the outer circumferential surface of the ignition cable are bonded to each other with an adhesive over the entire circumferential direction. plug cap device. [Claim 2] Inside the vertically long cylindrical plug cap body,
A discharge tube unit is installed between a cable-side connection terminal connected to an ignition cable terminal inserted from one end in the longitudinal direction and a plug-side connection terminal for connecting a spark plug arranged at the other end. In the plug cap device in which at least one of the synthetic resin portion of the plug cap main body corresponds to the cable side connection terminal position or the plug side connection terminal position corresponds to the other, and A surface layer made of rubber or an organic material other than rubber that does not contain aluminum or calcium as an element as a filler is provided on either the outer peripheral surface side or the inner peripheral surface side of the part, or both sides thereof. A plug cap device characterized by: