WO2012137395A1

WO2012137395A1 - Plug cap

Info

Publication number: WO2012137395A1
Application number: PCT/JP2012/000797
Authority: WO
Inventors: 智弘夫馬; 吉田　和正; 淳平太田
Original assignee: 日本特殊陶業株式会社
Priority date: 2011-04-07
Filing date: 2012-02-07
Publication date: 2012-10-11
Also published as: JP2012221669A

Abstract

Provided is a plug cap that can improve freedom in shape design and improve productivity. A plug cap (1) is provided with a terminal body (2) which is provided on one end side with a plug connecting part (7) to which a spark plug is connected and provided on the other end side with a cord connecting part (6) to which a plug cord is connected, and a connector part (3), which is provided between the plug connecting part (7) and cord connecting part (6) and is electrically connected with the spark plug. The terminal body (2) is provided with a terminal body main body (5) as a resin part formed from a conductive resin, and the connector part (3) and the cord connecting part (6) are electrically connected via the terminal body main body (5).

Description

Plug cap

The present invention relates to a plug cap for electrically connecting a spark plug and a plug cord.

The plug cap electrically connects an ignition plug attached to an internal combustion engine or the like and a plug cord extending from an ignition coil or a distributor in order to supply electric power to the ignition plug. The plug cap is provided with a terminal body. The terminal body is disposed on the inner periphery of the cylindrical terminal body body formed of an insulating resin and the terminal body body. And an electrical connection portion to be connected. Furthermore, a cord connecting portion including a cylindrical cord insertion portion into which the plug cord is inserted and a metal cord attaching screw into which the plug cord is screwed is provided at one end portion of the terminal body. On the other hand, the other end portion of the terminal body is provided with a cylindrical plug connection portion into which a terminal electrode of the ignition plug is inserted, and a metal connector portion with which the terminal electrode contacts. *

In general, the electrical connection portion is configured by connecting metal parts such as a spring and a plate, a resistor for noise suppression, and the like in series (for example, see Patent Document 1). Further, as the resistor, a ceramic resistor made of a conductive ceramic or a winding resistor formed by winding a metal wire is generally used.

JP 2010-160900 A

By the way, when an electrical connection part is constituted by a metal part, a ceramic resistor or the like, it becomes necessary to set the shape of the terminal body and thus the plug cap in accordance with the shape of the metal part or the resistor (that is, Due to the presence of metal parts and resistors, the plug cap shape design is limited). *

In general, since it takes a lot of time to produce a ceramic resistor or a winding resistor, using a ceramic resistor or the like may be disadvantageous in terms of productivity. *

This invention is made | formed in view of the said situation, The objective is to provide the plug cap which can aim at the freedom degree regarding a shape design, and the improvement of productivity.

Hereinafter, each configuration suitable for solving the above-described object will be described in terms of items. In addition, the effect specific to the corresponding structure is added as needed. *

Configuration 1. The plug cap of this configuration is provided with a terminal body provided with a plug connection part to which an ignition plug is connected on one end side, and provided with a cord connection part to which a plug cord is connected on the other end side; A plug cap provided between a cord connection portion and a connector portion electrically connected to the spark plug, wherein the terminal body is provided with a resin portion formed of a conductive resin The connector part and the cord connecting part are electrically connected via the resin part. *

Configuration 2. The plug cap of this configuration is characterized in that, in the above configuration 1, the connector portion and the cord connecting portion are electrically connected only through the resin portion. *

In addition, there are fewer restrictions on the shape design due to the presence of metal parts and resistors, and plug caps of various shapes can be manufactured. *

Configuration 3. The plug cap of this configuration is characterized in that, in the

above configuration

1 or 2, the entire terminal body is the resin portion. *

Furthermore, restrictions on the shape of the plug cap due to the presence of metal parts and resistors can be further reduced. *

Configuration 4. The plug cap of this configuration is characterized in that, in any one of the above configurations 1 to 3, the entire terminal body and the connector portion are formed of a conductive resin. *

Configuration 5. The plug cap of this configuration is characterized in that, in any one of the above configurations 1 to 4, the outer peripheral surface of the resin portion is covered with an insulating material made of resin, elastomer, or rubber. *

According to the plug cap of Configuration 1, the connector portion and the cord connecting portion are electrically connected via the resin portion made of conductive resin. Therefore, the degree of freedom regarding the shape design of the electrical connection portion that electrically connects the connector portion and the cord connection portion can be increased. As a result, the degree of freedom regarding the shape design of the terminal body and thus the plug cap can be effectively improved. *

Moreover, according to the plug cap of the structure 1, it can comprise so that a resin part may function as a resistor. Here, in general, a resistor (resin portion) made of a conductive resin is easier to manufacture than a ceramic resistor or a winding resistor. Therefore, by using the resin portion as a resistor, the time required for manufacturing the resistor can be reduced, and as a result, productivity can be improved. *

According to the plug cap of Configuration 2, the connector portion and the cord connecting portion are electrically connected via only the resin portion (that is, the electrical connecting portion is constituted by the resin portion). Accordingly, the number of parts can be reduced, and the manufacturing cost can be reduced. *

According to the plug cap of Configuration 3, since the entire terminal body is a resin portion made of a conductive resin, it is not necessary to separately provide a metal cord mounting screw or the like, and the number of parts can be further reduced. Furthermore, since the terminal body functions as a resistor, it is not necessary to provide a separate resistor. As a result, the manufacturing cost can be further reduced. *

According to the plug cap of the structure 4, the whole terminal body and the connector part are formed of the conductive resin. That is, the spark plug and the plug cord are electrically connected only through the resin portion. Thereby, there is no restriction of the shape surface due to the presence of metal parts and resistors, and the degree of freedom regarding the shape design of the plug cap can be further improved. *

According to the plug cap of the structure 5, it is comprised so that the outer periphery of the resin part may be covered with an insulating substance. For this reason, it is possible to more reliably prevent the occurrence of creeping discharge over the surface of the resin portion when power is supplied to the spark plug. As a result, it is possible to effectively suppress the situation where the noise suppression effect is reduced due to creeping discharge. In addition, when metal parts are arranged around the resin part, it is possible to suppress the occurrence of corona discharge between the resin part and the metal part, thereby preventing abrupt corrosion of the metal part. it can. *

Further, when the entire terminal body is formed of a conductive resin as in the configuration 3 and the configuration 4 described above (the entire terminal body is a resin portion), the terminal body and a metal disposed around the terminal body are made. Current leakage with the other parts (for example, plug holes provided in the internal combustion engine) can be more reliably prevented. As a result, power can be more reliably supplied to the spark plug.

It is sectional drawing which shows the structure of a plug cap. It is sectional drawing of the plug cap for demonstrating another example of the fixing method of the cord attachment screw with respect to a terminal body main body. It is sectional drawing of the plug cap for demonstrating another example of a connector part. It is sectional drawing which shows the structure of the plug cap in 2nd Embodiment. It is a partial expanded sectional view which shows a resistor, a covering, etc. It is sectional drawing which shows structures, such as a cord attachment screw in another embodiment. It is sectional drawing which shows structures, such as a connector part in another embodiment. It is sectional drawing which shows the structure of the plug cap in another embodiment. It is sectional drawing which shows the structure of the plug cap in another embodiment.

Hereinafter, embodiments will be described with reference to the drawings. 1ST EMBODIMENT As shown in FIG. 1, the plug cap 1 is provided with the terminal body 2, the connector part 3, and the coating | coated body 4. As shown in FIG. *

The terminal body 2 includes a terminal body main body 5 as a resin portion that is formed of a conductive resin and bends at a substantially right angle at a substantially middle portion thereof. As the conductive resin, for example, resin materials such as phenol resin, unsaturated polyester resin, PPS resin, metal powder (for example, copper, silver, copper alloy, nickel, etc.), metal fiber (for example, stainless fiber, etc.) ), So-called composite conductive resin in which at least one of conductive materials such as carbon fiber, carbon powder, metal oxide (for example, tin oxide, zinc oxide, indium oxide, etc.) is mixed is suitably used. Depending on the case, an intrinsic conductive resin such as polyacetylene or polypyrrole may be used. *

Further, the terminal body 2 includes a cord connection portion 6 and a plug connection portion 7. *

The cord connecting portion 6 includes a cylindrical cord insertion portion 61 provided on one end side of the terminal body main body 5 and a cord attaching screw 62. *

The cord insertion portion 61 has a cylindrical shape extending along the first axis CL1, and a plug cord (not shown) extending from an ignition coil and a distributor (not shown) is inserted therethrough. *

The cord attachment screw 62 is made of a conductive metal (for example, brass) and has a wood screw shape extending along the first axis CL1. Further, the screw-shaped portion of the cord attachment screw 62 is disposed so as to protrude toward the cord insertion portion 61. Further, a constricted protrusion 62P is formed on the opposite side of the screw-shaped portion of the cord attachment screw 62, and the protrusion 62P is press-fitted into the terminal body 5 so that the cord attachment screw 62 is pressed. Is fixed to the terminal body 5. Further, when connecting the plug cord, the end portion of the plug cord is inserted into the cord insertion portion 61 and the end portion of the plug cord is screwed into the cord attachment screw 62 so that the lead wire in the plug cord and the cord attachment screw are inserted. 62 is electrically connected. *

In addition, as shown in FIG. 2, for example, as shown in FIG. The cord attaching screw 62 may be fixed to the terminal body main body 5 by fitting the washer LW1 and LW2 in the shape of the terminal. *

Returning to FIG. 1, the plug connection portion 7 is provided on the other end side of the terminal body main body 5 and has a cylindrical shape extending along the second axis CL 2. A terminal electrode and an insulator of a spark plug (not shown) attached to an internal combustion engine (not shown) are inserted into the plug connection portion 7. *

Further, the connector portion 3 is formed of a conductive metal (for example, brass) having a bottomed cylindrical shape, and the other end portion is disposed in the plug connection portion 7. Further, the connector part 3 is fixed to the terminal body main body 5 by press-fitting one end thereof into the terminal body main body 5. In addition, an annular connector spring 31 is attached to the outer periphery of the connector portion 3. When the plug cap 1 is connected to the spark plug, a tightening force is applied from the connector spring 31 toward the terminal electrode of the spark plug inward in the radial direction. As a result, the connector portion 3 is connected to the spark plug. Can be electrically connected in a stable state. *

As shown in FIG. 3, a rod-like protrusion 3 P is provided at one end of the connector portion 3, and the amount of insertion into the terminal body main body 5 is increased, so that the connector portion 3 is more connected to the terminal body main body 5. It may be fixed in a stable state. Moreover, when fixing the connector part 3 and the cord attachment screw 62 with respect to the terminal body main body 5, you may use methods other than the above. Therefore, for example, the connector portion 3 is placed at a predetermined position of a mold for molding the terminal body body 5.
Alternatively, the connector portion 3 or the like may be fixed to the terminal body main body 5 by forming the terminal body main body 5 after the cord attaching screw 62 is disposed.

Returning to FIG. 1, in the present embodiment, as described above, since the terminal body main body 5 is formed of a conductive resin, the connector portion 3 and the cord connecting portion 6 (the cord attaching screw 62) are connected to the terminal body main body 5. It is electrically connected only through (that is, the resin portion). Further, the electrical resistance between the connector portion 3 and the cord connection portion 6 is set to a predetermined resistance value (for example, 5 kΩ), and the terminal body body 5 has a function as a resistor for noise suppression. It is configured. *

The covering body 4 is formed of an insulating material made of resin, elastomer, or rubber (for example, silicone rubber, fluorine rubber, acrylic rubber, fluorine resin, etc. having excellent heat resistance), and the outer periphery of the terminal body body 5 A covering body main body 41, one end side covering body 42 provided on one end side, and another end side covering body 43 provided on the other end side. *

The cover body 41 is bent at a substantially right angle at a substantially middle portion of the cover body 41, and the inner periphery of the cover body 41 is formed along the outer periphery shape of the terminal body body 5. *

The one end side covering body 42 has a cylindrical shape extending along the first axis CL1. Further, the inner diameter of the one end side cover 42 is configured to be smaller than the inner diameter of the cover body 41 and slightly smaller than the outer diameter of the plug cord. The surface is provided with a plurality of annular ridge portions 42 P that are formed to project radially inward. For this reason, when the plug cord is connected to the plug cap 1, the one end side cover 42 is pushed and spread by the plug cord, and the outer peripheral surface of the plug cord and the protruding portion 42P are brought into close contact with each other. As a result, entry of water into the cord connecting portion 6 is prevented. *

The other end side covering body 43 has a cylindrical shape extending along the second axis CL2, and is configured such that its inner diameter is slightly smaller than the outer diameter of the rear end portion of the insulator of the spark plug. In addition, similarly to the one end side covering body 42, a plurality of annular protrusions 43 P that are formed to protrude radially inward are provided on the inner peripheral surface of the other end side covering body 43. When the plug cap 1 is connected to the spark plug, the other end side covering body 43 is spread by the insulator of the spark plug, and the outer peripheral surface of the insulator of the spark plug and the protrusion 43P are in close contact with each other. As a result, entry of water into the plug connection portion 7 is prevented. *

As described above in detail, according to the present embodiment, the connector portion 3 and the cord connecting portion 6 (the cord attaching screw 62) are electrically connected only via the terminal body main body 5 made of conductive resin. . Accordingly, it is possible to reduce restrictions in terms of shape design due to the presence of metal parts and resistors, and it is possible to manufacture plug caps 1 having various shapes. *

In addition, it is possible to reduce the number of parts for electrically connecting the connector portion 3 and the cord connecting portion 6 and to reduce the manufacturing cost. Furthermore, in this embodiment, since the terminal body main body 5 is configured to function as a resistor, it is not necessary to provide a separate resistor, and the manufacturing cost can be further reduced. *

In addition, since the terminal body main body 5 is covered with the covering 4 made of an insulating material, the terminal body 2 and metal parts disposed around the terminal body 2 (for example, a plug hole provided in the internal combustion engine). Current leakage between the two can be more reliably prevented. As a result, power can be more reliably supplied to the spark plug. Second Embodiment Next, a second embodiment will be described with a focus on differences from the first embodiment. In the first embodiment, the connector portion 3 and the cord connecting portion 6 are electrically connected only through the terminal body main body 5. On the other hand, in the second embodiment, as shown in FIG. 4, the terminal body 12 includes a cylindrical terminal body main body 121 made of an insulating resin and a conductive material disposed on the inner periphery of the terminal body main body 121. The plug cap 11 is configured so as to be provided with the electrical connection portion 122 having the same characteristics. And the connector part 13 and the cord connection part 16 are electrically connected via the electrical connection part 122. Moreover, the electrical connection part 122 has a resistor formed in a cylindrical shape by a conductive resin. A body 15 (corresponding to a resin portion) is interposed. That is, the resistor 15 is configured to play a part in the electrical connection path between the connector portion 13 and the cord connection portion 16. *

The resistor 15 has a predetermined electric resistance (for example, 5 kΩ) and has a function of suppressing radio noise. In addition, as shown in FIG. 5, metal contact caps 18 A and 18 B each having a bottomed cylindrical shape are disposed at both ends of the resistor 15. Then, the contact cap 18 A comes into contact with the cord attachment screw 162, so that one end of the resistor 15 and the cord attachment screw 162 are electrically connected. The contact cap 18B is in contact with a contact spring 19 formed of a conductive metal (for example, stainless steel), and the other end portion of the resistor 15 and the connector portion 13 are electrically connected via the contact spring 19. It is connected to the. By providing the contact spring 19, the vibration resistance is enhanced, and the connection from the connector portion 13 to the cord attachment screw 162 is electrically connected in a stable state. *

Further, a cylindrical covering 14 formed of an insulating material made of resin, elastomer, or rubber is provided on the outer periphery of the resistor 15. One end of the cover 14 is interposed between the cylindrical portion of the contact cap 18A and the outer peripheral surface of the resistor 15, and the other end is disposed on the outer periphery of the cylindrical portion of the contact cap 18B. The end portion of the cover 14 may be disposed on the outer periphery of the cylindrical portion of the

contact cap

18A, 18B, or between the cylindrical portion of the

contact cap

18A, 18B and the outer peripheral surface of the resistor 15. May be. That is, it is only necessary that the surface of the resistor 15 is not in contact with oxygen or the like as much as possible by the covering body 14. *

Also, as shown in FIG. 4, cylindrical rubber members RE1 and RE2 are connected to both ends of the terminal body main body 121, respectively, so that water enters the connector portion 13 and the cord attachment screw 162 side. Is prevented. *

As described above, according to the second embodiment, the connector portion 13 and the cord connecting portion 16 are electrically connected via the resistor 15 made of conductive resin. Therefore, the degree of freedom regarding the shape design of the electrical connection portion 122 that electrically connects the connector portion 13 and the cord connection portion 16 can be increased. As a result, the degree of freedom regarding the shape design of the terminal body 12 and hence the plug cap 11 can be effectively improved. *

In general, the resistor 15 (resin portion) made of a conductive resin is easier to manufacture than a ceramic resistor or a winding resistor. Therefore, the time required for producing the resistor 15 can be reduced, and productivity can be improved. *

In addition, in the second embodiment, the outer periphery of the resistor 15 is covered with a covering 14 made of an insulating material. Therefore, it is possible to more reliably prevent the occurrence of creeping discharge over the surface of the resistor 15 when power is supplied to the spark plug. As a result, it is possible to effectively suppress the situation where the noise suppression effect is reduced due to creeping discharge. Further, the generation of corona discharge between the resistor 15 and the contact caps 18A and 18B can be suppressed, and the rapid corrosion of the contact caps 18A and 18B and consequently the resistance value of the electrical connection portion 122 are rapidly increased. It can prevent more reliably. *

In addition, it is not limited to the description content of the said embodiment, For example, you may implement as follows. Of course, other application examples and modification examples not illustrated below are also possible. *

(A) In the first embodiment, the cord attachment screw 62 is made of a metal material. However, as shown in FIG. 6, the cord attachment screw 262 is made of a conductive resin, so that the terminal body main body 25 and The cord attaching screw 262 may be integrally formed. That is, the entire terminal body 22 may be formed of a conductive resin. In this case, it is not necessary to separately provide a metal cord mounting screw, and the number of parts can be further reduced. Furthermore, restrictions on the shape of the plug cap can be further reduced. *

(B) In the said 1st Embodiment, although the connector part 3 is formed with the metal material, as shown in FIG. 7, the terminal body main body 25 and the connector part are formed by forming the connector part 23 with a conductive resin. 23 may be formed of a conductive resin. *

Further, as shown in FIG. 8, both the connector portion 23 and the cord attachment screw 262 may be formed of a conductive resin, so that the entire terminal body 22 and the connector portion 23 may be formed of a conductive resin. In other words, the spark plug and the plug cord may be electrically connected only through a resin portion made of a conductive resin. In this case, there is no restriction on the shape surface due to the presence of the metal part, and the degree of freedom regarding the shape design of the plug cap can be further improved. *

(C) In the second embodiment, the terminal body main body 121 is formed of an insulating resin. However, as shown in FIG. 9, a part of the terminal body main body 321 is formed of a conductive resin, and the conductive body The connector part 33 and the cord connecting part 36 may be electrically connected via a resin part 35 formed of resin and a contact spring 39. In this case, the resin part 35 which is a part of the terminal body main body 321 plays a role as a resistor, and the cost can be reduced as compared with a case where a resistor is provided separately. *

(D) In the above embodiment, a plug cap that is bent at a substantially right angle is illustrated, but the shape of the plug cap is not particularly limited.

DESCRIPTION OF

SYMBOLS

1,11 ... Plug cap, 2,12 ... Terminal body, 3, 13, 23, 33 ... Connector part, 4,14 ... Covering body, 5 ... Terminal body main body (resin part), 6,16 ... Cord connection part, 7 ... Plug connection part, 15 ... Resistor (resin part), 35 ... Resin part.

Claims

A plug connection part to which a spark plug is connected at one end side and a terminal body provided with a cord connection part to which a plug cord is connected at the other end side is provided between the plug connection part and the cord connection part. A plug cap provided with a connector portion electrically connected to the spark plug, wherein the terminal body is provided with a resin portion formed of a conductive resin, via the resin portion; A plug cap, wherein the connector portion and the cord connecting portion are electrically connected.
The plug cap according to claim 1, wherein the connector portion and the cord connecting portion are electrically connected through only the resin portion.
The plug cap according to claim 1 or 2, wherein the entire terminal body is the resin portion.
The plug cap according to any one of claims 1 to 3, wherein the entire terminal body and the connector portion are formed of a conductive resin.
The plug cap according to any one of claims 1 to 4, wherein an outer peripheral surface of the resin portion is covered with an insulating substance made of resin, elastomer, or rubber.