JP5054798B2 - Plug cap and manufacturing method thereof - Google Patents

Description

  The present invention relates to a plug cap for electrically connecting a spark plug and a plug cord, and a manufacturing method thereof.

  The plug cap electrically connects a spark plug attached to the internal combustion engine and a plug cord extending from an ignition coil or a distributor in order to apply a high voltage to the spark plug. As the plug cap, there is known a plug cap which is formed of a resin and includes a terminal body having at least both ends in a cylindrical shape and a cylindrical rubber member attached to an end portion of the terminal body. When the plug cap is connected to the spark plug or the plug cord, the spark plug or the like is inserted into the rubber member, and the gap between the spark plug or the like and the rubber member is sealed (for example, Patent Document 1) reference).

  By the way, the said terminal body may have an uneven | corrugated engaging part in the outer peripheral surface. Further, as the terminal body, not only a straight body but also a terminal body bent at a predetermined position in order to correspond to an assembled state of the spark plug with respect to the internal combustion engine or the like. Therefore, in forming the terminal body as described above, the outer portion of the terminal body cannot be molded using only one mold. Therefore, the terminal body is generally formed by molding using a plurality of split molds. For example, as shown in FIGS. 11A and 11B, a pin 91 (not shown) for defining the inner peripheral portion of the terminal body and a split mold 91 having a molding surface corresponding to the outer shape of the terminal body. , 92 are placed at predetermined positions and the mold is closed. Next, a resin in a plasticized state is filled in a cavity (space) formed by the pins and the split dies 91 and 92, and then the resin is solidified. Thereafter, the split dies 91 and 92 are opened, and the pins are removed, whereby the terminal body 93 shown in FIGS. 12A and 12B is formed.

JP 2001-155837 A

  However, when the terminal body is formed by the above-described method, the outer peripheral surface of the terminal body 93 has protrusions (mold dividing lines) PL1 and PL2 extending along the longitudinal direction corresponding to the butting parts of the split molds 91 and 92. In some cases, the protrusions PL1 and PL2 are emphasized in FIGS. 12A and 12B. Therefore, in the site | part where the said projection parts PL1 and PL2 are located, the inner peripheral surface of a rubber member and the outer peripheral surface of a terminal body do not fully adhere | attach, and there exists a possibility that water may infiltrate from both. If water enters and adheres to the spark plug or the plug cord, current leakage may occur, and a high voltage may not be applied to the spark plug.

  In recent years, the internal combustion engine has been highly compressed in order to improve the fuel consumption, and in such an internal combustion engine, the voltage (required voltage) required for spark discharge is further increased. Therefore, even when a very small amount of water enters, there is a possibility that current leakage may occur.

  The present invention has been made in view of the above circumstances, and the object thereof is to suppress the intrusion of water from between the terminal body and the rubber member, and to more reliably prevent current leakage. It is to propose a plug cap that can be manufactured and a method of manufacturing the same.

  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 includes an electrical connection portion that electrically connects the spark plug and the plug cord,
A terminal body provided on the outer peripheral side of the electrical connection part;
A cylindrical rubber member attached to one end of the terminal body and through which the spark plug or the plug cord is inserted;
The terminal body has a cylindrical insertion portion through which the spark plug or the plug cord is inserted at one end of the terminal body, and a plug cap in which a protrusion extending along the longitudinal direction of the terminal body is present on the outer peripheral surface of the terminal body Because
In the outer peripheral surface of the terminal body, at least a part of the portion covered with the rubber member does not have the protruding portion over the entire periphery.

  According to the configuration 1, at least a part of the outer peripheral surface of the terminal body that is covered with the rubber member has no protrusion, and the part is smooth (flat) over the entire circumference. It is configured to have a shape. Therefore, the smooth outer peripheral surface of the terminal body and the inner peripheral surface of the rubber member can be brought into close contact with each other more reliably, and water intrusion from between the terminal body and the rubber member can be suppressed. As a result, current leakage can be prevented more reliably.

Configuration 2. The plug cap of this configuration includes an electrical connection portion that electrically connects the spark plug and the plug cord,
A terminal body provided on the outer peripheral side of the electrical connection part;
A cylindrical rubber member attached to one end of the terminal body and through which the spark plug or the plug cord is inserted;
The terminal body has a cylindrical insertion portion through which the spark plug or the plug cord is inserted at one end of the terminal body, and a plug cap in which a protrusion extending along the longitudinal direction of the terminal body is present on the outer peripheral surface of the terminal body Because
One end of the terminal body is located closer to one end than one end of the protrusion.

  According to the configuration 2, one end of the terminal body is located closer to one end than the one end of the protrusion. That is, the protruding portion is formed without reaching one end of the terminal body, and the portion between the one end of the protruding portion and the one end of the terminal body on the outer peripheral surface of the terminal body has a smooth shape over the entire circumference. It is comprised so that. Therefore, the smooth outer peripheral surface of the terminal body and the inner peripheral surface of the rubber member can be brought into close contact with each other more reliably, and more reliably prevent water intrusion and current leakage caused thereby. Can do.

  Configuration 3. The plug cap of this configuration is characterized in that, in the above configuration 1 or 2, the outer peripheral surface of the terminal body is formed with an annular projection that extends along the circumferential direction and contacts one end of the projection. To do.

  According to the said structure 3, the effect similar to the said structure 1 etc. is show | played fundamentally.

  The “annular protrusion” refers to, for example, a protrusion (parting line) formed at the abutting portion between the one-end mold member used in the plug cap manufacturing method described later and another mold member.

  Configuration 4. In the plug cap of this configuration, in any one of the above configurations 1 to 3, an annular protrusion extending along the circumferential direction is formed on a portion of the outer peripheral surface of the terminal body covered with the rubber member. It is characterized by that.

  According to the said structure 4, the cyclic | annular protrusion part extended in the circumferential direction is formed in the site | part covered with the said rubber member among the outer peripheral surfaces of a terminal body. Therefore, even when water enters the protrusion between the terminal body and the rubber member, further intrusion of water can be suppressed by the annular protrusion. That is, according to the said structure 4, intrusion of water can be effectively suppressed by both the cyclic | annular protrusion part and the contact | adherence part of a terminal body and a rubber member. As a result, current leakage can be prevented more reliably.

  Configuration 5. In the plug cap of this configuration, in the above configuration 3 or 4, the inner peripheral portion of the rubber member is engaged with the outer peripheral surface of the terminal body at a position spaced from the one end to the other end by a predetermined distance. And the annular protrusion is formed on the surface of the engaging portion.

  Note that “predetermined distance” means a distance including “zero”. Therefore, it is good also as providing an engaging part in the most end side of a terminal body (hereinafter the same).

  In order to attach the rubber member to one end of the terminal body in a stable state, a convex engagement portion is provided on the terminal body, and the rubber member is engaged with the engagement portion. It is conceivable to attach a rubber member.

  In the case where such an engaging portion exists, according to the configuration 5, the annular protrusion is formed on the surface of the engaging portion having a convex shape and a relatively large outer diameter. For this reason, an annular protrusion part can be made to project to the outer peripheral side, and the infiltration suppression effect of water can be heightened more. As a result, current leakage can be more reliably prevented.

Configuration 6. The plug cap according to this configuration is the plug cap according to any one of the above configurations 1 to 5, wherein the terminal body has a convex engagement portion on the outer peripheral surface thereof at a position spaced from the one end to the other end by a predetermined distance. ,
The terminal body has a constant outer diameter at a portion closer to one end than the engaging portion, or is made smaller toward one end.

  According to the configuration 6, since the outer diameter of one end side of the terminal body is constant or gradually smaller than the engaging portion, the inner diameter of the rubber member attached to the one end portion of the terminal body is increased. It can be relatively small. Therefore, it is possible to improve the adhesion of the rubber member to the terminal body, and more effectively suppress the intrusion of water.

  In addition, as in the above configuration 1, in order to configure so that no protrusion is present in at least a portion of the outer peripheral surface of the terminal body that is covered with the rubber member, for example, A method may be considered in which one end portion is molded using a cylindrical mold member, and after the molding, the mold member is moved along the longitudinal direction (direction perpendicular to the radial direction) of the terminal body and removed from the terminal body. . And when providing an engaging part in the outer peripheral surface of a terminal body, it is possible to shape | mold the site | part of the one end side rather than an engaging part with the said cylindrical metal mold member. However, it is difficult to remove the mold member from the terminal body if the part on one end side of the engaging part is enlarged toward one end side or there is unevenness on the part on one end side. May end up.

  In this regard, according to the configuration 6, when the one end portion of the terminal body is formed using the cylindrical mold member, the mold member can be removed more easily. As a result, the workability can be further improved.

Configuration 7. In the plug cap of this configuration, in any one of the above configurations 1 to 6, the inner peripheral surface of the rubber member is formed with at least one annular convex portion at a portion in contact with the outer peripheral surface of the terminal body. ,
The part of the portion corresponding to the convex portion of the outer peripheral surface of the terminal body, wherein the projections are not present.

  According to the said structure 7, the at least 1 cyclic | annular convex part is formed in the internal peripheral surface of a rubber member. Therefore, the convex portion comes into contact with the terminal body with a larger pressure, and water intrusion can be further suppressed.

Further, with the above configuration 7, the part of the portion corresponding to the convex portion of the outer peripheral surface of the terminal body, the protrusion is configured to not present. Therefore, the convex part of a rubber member can be made to adhere | attach more reliably with respect to a terminal body, As a result, the further improvement of a water immersion suppression effect can be aimed at.

Configuration 8. The manufacturing method of the plug cap of this configuration includes an electrical connection portion that electrically connects the spark plug and the plug cord,
A terminal body provided on the outer peripheral side of the electrical connection portion,
The terminal body is a method of manufacturing a plug cap having a cylindrical insertion part through which the spark plug or the plug cord is inserted at one end of the terminal body,
Including a mold forming step of forming the terminal body by mold molding;
In the mold forming step, a molding die including a plurality of mold members, including at least one end side mold member for molding at least a part of one end side portion of the outer peripheral surface of the terminal body. Used,
The mold forming step
A mold closing step of closing the molding die;
A forming step of forming the terminal body by filling a material for forming the terminal body in a cavity portion provided inside the molding die and having a shape corresponding to the outer shape of the terminal body;
A mold opening step of opening the molding die and taking out the terminal body,
In the mold opening step, the one end side mold member and the terminal body are separated in a direction perpendicular to the radial direction of the terminal body.

  According to the configuration 8, when the terminal body is formed by molding, in the mold opening process, the one end side mold is separated from the one end side mold member and the terminal body in a direction perpendicular to the radial direction of the terminal body. The mold member is removed from the terminal body. Accordingly, at least the outer peripheral surface of the portion formed by the mold member on the one end side of the terminal body can be configured such that no protrusion exists without special treatment. That is, in the plug cap obtained by the manufacturing method of the above configuration 8, the same effects as the above configuration 1 and the like are exhibited. Moreover, since the outer peripheral surface of the terminal body can be formed in a smooth shape without performing special processing, the manufacturing cost can be suppressed.

Configuration 9 The plug cap manufacturing method of this configuration is the above-described configuration 8, wherein the terminal body has a convex engaging portion on the outer peripheral surface thereof at a position spaced from the one end to the other end by a predetermined distance,
A portion on one end side from the engagement portion is formed by the one end side mold member.

  When the projecting engagement portion is provided on the outer peripheral surface of the terminal body as in the configuration 9, when the portion on the other end side than the engagement portion is molded by the one end side mold member, the one end side mold member There is a risk that it will be difficult to withdraw.

  In this regard, according to the configuration 9, the one end side mold member is formed by the one end side mold member from the engagement portion, so that the one end side mold member can be easily pulled out. Can do. As a result, productivity can be improved.

(A) is a front view of a plug cap, (b) is a side view of a plug cap. It is sectional drawing which shows the structure of a plug cap. It is a partially broken front view which shows another example of the formation position of a 1st engaging part and a 2nd engaging part. (A) is a front view of the molding die for forming the terminal body, (b) is a side view of the molding die. It is sectional drawing of the metal mold | die for shaping | molding. It is a partially broken enlarged view which shows the structure of the plug side rubber member in another embodiment. It is the elements on larger scale which show the formation position etc. of the annular projection part in another embodiment. It is a front view which shows the structure of the plug cap in another embodiment. It is a front view of the plug cap which shows the shape of the other end side surface of the plug side rubber member and cord side rubber member in another embodiment. (A), (b) is a partial expanded sectional view which shows the structure of the engaging part in another embodiment. It is a figure explaining the metal mold | die at the time of forming a terminal body in a prior art, (a) is a front view of a metal mold | die, (b) is a side view of a metal mold | die. It is a figure which shows the terminal body manufactured by the prior art, Comprising: (a) is a front view of a terminal body, (b) is a side view of a terminal body.

  Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1A is a front view of the plug cap 1, and FIG. 1B is a side view of the plug cap 1. FIG. 2 is a cross-sectional view of the plug cap 1.

  The plug cap 1 includes a bent terminal body 2, a plug-side rubber member 3 attached to one end portion thereof, and a cord-side rubber member 6 attached to the other end portion (the plug-side rubber member 3 and the cord portion). The side rubber member 6 corresponds to the rubber member in the present invention.

  The terminal body 2 has a cylindrical shape and is formed of a resin (for example, phenol resin) having excellent heat resistance and voltage resistance. The terminal body 2 is bent at a substantially right angle at a substantially middle portion, and is substantially orthogonal to the first body component 21 having a relatively large diameter extending along the first axis CL1 and the first axis CL1. The second body constituting portion 22 extends along the second axis CL2 and has a smaller diameter than the first body constituting portion 21.

  In the present invention, the side on which the plug-side rubber member 3 or the cord-side rubber member 6 is attached is one end side of the terminal body 2, but in this embodiment, with respect to both end portions of the terminal body 2. The plug side rubber member 3 and the cord side rubber member 6 are respectively attached. Therefore, for convenience of explanation, in the following, in the terminal body 2, the opening side of the first body component 21 is defined as the first end side, the opening side of the second body component 22 is defined as the second end side, Description will be made assuming that the intersections of the first axis CL1 and the second axis CL2 are the other end sides.

  Returning to the description of the terminal body 2, a convex first engaging portion 23 is formed on the outer periphery of the first body constituting portion 21 at a position spaced from the first end to the other end side by a predetermined distance. A convex second engaging portion 24 is formed on the outer periphery of the second body constituting portion 22 at a position spaced a predetermined distance from the second end to the other end side. The “predetermined distance” is a distance including “zero”. Therefore, as shown in FIG. 3, the first engagement portion 83 may be provided at the first end of the terminal body 8 and the second engagement portion 84 may be provided at the second end of the terminal body 8.

  Returning to FIGS. 1 and 2, the terminal body 2 has a shaft hole 4 including a first shaft hole 41 extending along the first axis CL <b> 1 and a second shaft hole 42 extending along the second axis CL <b> 2. Is formed. A cylindrical first insertion portion 43 into which a terminal electrode of a spark plug (not shown) attached to an internal combustion engine (not shown) is inserted in the first one end side (first shaft hole 41) of the shaft hole 4. Is formed. On the other hand, a cylindrical second insertion portion 44 into which a plug cord (not shown) extending from an ignition coil or a distributor (not shown) is inserted is formed on the second end side (second shaft hole 42) of the shaft hole 4. Has been.

  Furthermore, in the shaft hole 4, an electrical connection portion 5 for electrically connecting the spark plug and the plug cord is provided. The electrical connection portion 5 is configured by connecting a connector fitting 51, a resistor 52, a contact spring 53, and a cord attachment screw 54 in series.

  The connector fitting 51 is made of a conductive metal (for example, brass) having a bottomed cylindrical shape, and a part thereof is disposed in the first insertion portion 43. In addition, an annular connector spring 51 </ b> A is attached to the outer periphery of the connector fitting 51. When the plug cap 1 is connected to the spark plug, a clamping force is applied to the terminal electrode of the spark plug from the connector spring 51A toward the inside in the radial direction. It can be connected to the spark plug in a stable state.

  The resistor 52 has a substantially cylindrical shape and is made of a conductive ceramic and has a predetermined electric resistance (for example, 5 kΩ). In addition, metal contact caps 55 and 56 are disposed at both ends of the resistor 52, and the resistor 52 and the connector fitting 51 are electrically connected via the contact cap 55.

  In addition, the contact spring 53 is made of a conductive metal (for example, stainless steel), one end of which is in contact with the contact cap 56, while the other end is the cord side mounting screw. 54 is in contact. The contact spring 53 increases the vibration resistance, and the connection from the connector fitting 51 to the cord attachment screw 54 is electrically connected in a stable state.

  The cord attachment screw 54 is made of a conductive metal (for example, brass) and has a wood screw shape extending along the second axis CL2. Further, the thread-shaped portion of the cord attachment screw 54 is disposed so as to protrude toward the second insertion portion 44. When connecting the plug cord, the end portion of the plug cord is inserted into the second insertion portion 44 and the end portion of the plug cord is screwed into the cord attachment screw 54, so that the conductors in the plug cord and the cord attachment are attached. The screw 54 is electrically connected. Two annular washers 57 and 58 are fitted on the outer periphery of the base end of the cord attachment screw 54. The cord attaching screw 54 is fixed to the terminal body 2 by the washers 57 and 58, and the cord attaching screw 54 is prevented from falling when the plug cord is connected.

  Furthermore, a cylindrical plug-side rubber member 3 into which a terminal electrode of the spark plug is inserted when connected to the spark plug is attached to the first end of the terminal body 2. The plug-side rubber member 3 is made of a predetermined rubber (for example, silicone rubber), and includes a small-diameter portion 31 having a relatively small diameter and a large-diameter portion 32 having a larger diameter than the small-diameter portion 31.

  The small-diameter portion 31 is configured such that the inner diameter thereof is slightly smaller than the outer diameter of the rear end portion of the insulator of the spark plug, and the inner peripheral surface of the small-diameter portion 31 is directed radially inward. A plurality of annular convex portions 31P are formed. For this reason, when the plug cap 1 is connected to the spark plug, the small diameter portion 31 is expanded by the insulator of the spark plug, and the outer peripheral surface of the spark plug and the convex portion 31P are in close contact with each other. As a result, intrusion of water into the first insertion portion 43 is prevented.

  The large-diameter portion 32 is formed on the other end side of the small-diameter portion 31, and a concave first annular engaged portion 33 is formed on the inner peripheral surface of the large-diameter portion 32. Yes. The plug-side rubber member 3 is engaged with the first end portion of the terminal body 2 in the large-diameter portion 32 while engaging the first engaging portion 23 with the first engaged portion 33. And attached to the first end of the terminal body 2. In the present embodiment, at least a portion on the first one end side of the inner peripheral surface of the plug-side rubber member 3 with respect to the first engaged portion 33 is formed to be smooth (flat). Moreover, the other end side surface 34 of the plug-side rubber member 3 is formed so as to extend in a direction (radial direction) orthogonal to the first axis CL1.

  Further, a cord-side rubber member 6 into which the plug cord is inserted when the plug cord is connected is attached to the second end portion of the terminal body 2. The cord side rubber member 6 is formed of a predetermined rubber (for example, EPDM rubber), and has a cylindrical shape extending along the second axis CL2. The cord-side rubber member 6 includes a large-diameter portion 61 and a small-diameter portion 62 having a smaller diameter than the large-diameter portion 61 on the second end side of the large-diameter portion 61.

  A concave second annular engaged portion 63 is formed on the inner peripheral surface of the large diameter portion 61. The cord-side rubber member 6 has the second engagement portion 24 of the terminal body 2 engaged with the second engaged portion 63 and the second end portion of the terminal body 2 within the large-diameter portion 61. By being inserted, the terminal body 2 is attached to the second end portion. In the present embodiment, at least a portion on the second one end side of the inner peripheral surface of the cord-side rubber member 6 with respect to the second engaged portion 63 is formed to be smooth (flat). The other end side surface 64 of the plug-side rubber member 6 is formed to extend in a direction (radial direction) orthogonal to the second axis CL1.

  Further, in the present embodiment, the terminal body 2 is formed by mold forming, which will be described later. On the outer peripheral surface of the terminal body 2, protrusions (parting lines) PL1 and PL2 extending along the longitudinal direction of the terminal body 2 are terminals. The body 2 is formed from the first one end side to the second one end side (in FIG. 2, the protrusions PL1 and PL2 are not shown). As the mold is formed, annular projections (parting lines) PL3 and PL4 extending in the circumferential direction are formed on the surfaces of the first engaging portion 23 and the second engaging portion 24.

  In the present embodiment, the first ends of the projecting portions PL1 and PL2 are configured to contact the annular projecting portion PL3, and the second ends of the projecting portions PL1 and PL2 are configured to contact the annular projecting portion PL4. In addition, the first end of the terminal body 2 is located closer to the first end than the first end of the protrusions PL1 and PL2, and the second end of the terminal body 2 is closer to the second end than the second end of the protrusions PL1 and PL2. The second end is located. That is, no protrusions PL1 and PL2 are present in a portion of the terminal body 2 (first body component 21) on the first end side of the annular protrusion PL3, and the terminal body 2 (second body component). 22), the protrusions PL1 and PL2 do not exist at the second end side of the annular protrusion PL4. In the present embodiment, a portion of the outer peripheral surface of the terminal body 2 that is closer to the first end than the annular protrusion PL3 has a smooth shape over the entire circumference, and the second end from the annular protrusion PL4. The site | part of the side has comprised smooth shape over the perimeter.

  In addition, in the present embodiment, the outer diameter of the first engaging portion 23 is made larger than the outer diameter of the first body constituting portion 21 other than the first engaging portion 23. In addition, the outer diameter of the second engaging portion 24 is made larger than the outer diameter of the second body constituting portion 22 other than the second engaging portion 24. That is, the terminal body 2 has the largest outer diameter of the first engaging portion 23 in the direction along the first axis CL1, and the outer diameter of the second engaging portion 24 in the direction along the second axis CL2. It is configured to be the largest.

  Further, the outer diameter D1 of the first body constituting portion 21 at the first end side of the first engaging portion 23 is constant, and similarly, the second body constituting portion 22 of the second engaging portion The outer diameter D <b> 2 at the portion on the second end side from the portion 24 is constant.

  Next, the manufacturing method of the terminal body 2 among the plug caps 1 described above will be described.

  The terminal body 2 is manufactured through a mold forming process. In the mold forming process, as shown in FIGS. 4 (a), 4 (b) and 5, a first end-side mold member M1, A molding die MO including a second one-end mold member M2, a pair of split molds M3 and M4, and pins P1 and P2 for defining an inner peripheral portion of the terminal body 2 is used. The one end side mold members M1 and M2 and the split molds M3 and M4 have an inner peripheral surface corresponding to the outer shape of the terminal body 2. In particular, the inner peripheral surface of the first end-side mold member M1 has a shape corresponding to a portion of the outer peripheral surface of the terminal body 2 that extends from the first end to substantially the middle of the first engaging portion 23. The inner peripheral surface of the two-end mold member M <b> 2 has a shape corresponding to a portion of the outer peripheral surface of the terminal body 2 from the second end to substantially the middle of the second engaging portion 24.

  The mold forming process includes a mold closing process, a forming process, and a mold opening process. First, in the mold closing step, the molding die MO is closed, and a cavity CA having a shape corresponding to the outer shape of the terminal body 2 is formed inside the molding die MO. Next, in the forming step, the cavity portion CA is filled with a softened resin (material for forming the terminal body 2) from a filling hole (not shown) provided in the molding die MO. The terminal body 2 is formed by solidifying the filled resin.

  Next, in the mold opening process, the molding die MO is opened and the terminal body 2 is taken out. In this mold opening process, the first one-end mold member M1 and the terminal body 2 are perpendicular to the radial direction of the terminal body 2 (particularly the portion formed by the first one-end mold member M1) ( That is, the first end mold member M1 is detached from the terminal body 2 by being separated in the first axis CL1 direction. In addition, the second one end side mold member M2 and the terminal body 2 are perpendicular to the radial direction of the terminal body 2 (particularly the portion formed by the second one end side mold member M2) (that is, the second axis CL2). The second end mold member M2 is removed from the terminal body 2 by being separated in the direction). After removing the mold members M1 and M2 on both ends, the split molds M3 and M4 and the pins P1 and P2 are removed, whereby the terminal body 2 is obtained. Note that the split molds M3 and M4 and the pins P1 and P2 may be removed before removing the one-end mold members M1 and M2, and the order of removing the molds can be changed as appropriate.

  As described above in detail, according to the present embodiment, at least a part of the outer peripheral surface of the terminal body 2 covered with the plug-side rubber member 3 or the cord-side rubber member 6 is provided with a protrusion. PL1 and PL2 are configured not to exist, and the portion on the first one end side from the annular protrusion PL3 and the portion on the second one end side from the annular protrusion PL4 are smooth over the entire circumference ( (Flat) shape. Accordingly, the smooth outer peripheral surface of the terminal body 2 and the inner peripheral surfaces of the rubber members 3 and 6 can be more securely brought into contact with each other, and water can enter from between the terminal body 2 and the rubber members 3 and 6. Can be suppressed. As a result, current leakage can be prevented more reliably.

  Furthermore, annular protrusions PL3 and PL4 are formed on the outer peripheral surface of the terminal body 2, and further intrusion of water can be suppressed by the annular protrusions PL3 and PL4. In particular, in this embodiment, since the annular protrusions PL3 and PL4 are formed on the surfaces of the engaging portions 23 and 24 having a relatively large outer diameter, it is possible to further enhance the water infiltration suppression effect.

  In addition, since the outer diameters D1 and D2 on one end side of the engagement portions 23 and 24 of the terminal body 2 are formed to be constant, the inner diameters of the rubber members 3 and 6 attached to the terminal body 2 Can be made relatively small. Therefore, it is possible to improve the adhesion of the rubber members 3 and 6 to the terminal body 2 and to more effectively suppress the intrusion of water.

  Further, the outer diameter of the first engaging portion 23 is larger than the outer diameter of the terminal body 2 (first body constituting portion 21) other than the first engaging portion 23, and the outer diameter of the second engaging portion 24 is larger. The diameter is made larger than the outer diameter of the terminal body 2 (second body constituting portion 22) other than the second engaging portion 24. In addition, the outer diameters D1 and D2 are constant, and further, a portion from the first engagement portion 23 to the first end of the terminal body 2 is molded by the first one-end mold member M1, A portion from the second meeting portion 24 to the second end of the terminal body 2 is formed by the second end-side mold member M2. Therefore, it is possible to easily remove the first one-end mold member M1 and the second one-end mold member M2, and the parts formed by the both one-end mold members M1 and M2 include: The protrusions PL1 and PL2 can be absent without performing special processing. That is, according to the manufacturing method of the present embodiment, it is possible to improve the water infiltration suppression effect without increasing the manufacturing cost.

  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 above-described embodiment, a portion of the outer peripheral surface of the terminal body 2 that is closer to the first end than the annular protrusion PL3 has a smooth shape over the entire circumference, and is second than the annular protrusion PL4. The part on one end side is smooth over the entire circumference, but from the viewpoint of suppressing the ingress of water, the plug-side rubber member 3 or the cord-side rubber member 6 on the outer peripheral surface of the terminal body 2 is used. It suffices that at least a part of the covered portion has a smooth shape over the entire circumference. Therefore, the part which makes smooth shape over the perimeter is not limited to the aspect of the said embodiment, For example, only a part of site | part of the one end side rather than the engaging parts 23 and 24 among the terminal bodies 2 is sufficient. However, it may be smooth over the entire circumference.

  (B) In the above embodiment, a portion of the inner peripheral surface of the plug-side rubber member 3 that is closer to the first end than the first engaged portion 33 is formed to be smooth (flat). 6, at least one annular recess 35 is formed in a portion of the plug-side rubber member 3 that contacts the outer peripheral surface of the terminal body 2, and other than the recess 35 of the inner peripheral surface of the plug-side rubber member 3. It is good also considering this site | part as the protruding convex part 36. In this case, the convex portion 36 comes into contact with the terminal body 2 with a larger pressure, and water intrusion can be further suppressed.

Also, in the provision of the protrusion 36, the protrusion PL1, PL2 are so not present in the part of the portion corresponding to the convex portion 36, it is preferable to configure the terminal body 2 and the plug-side rubber member 3. In this case, the convex portion 36 can be more closely attached to the terminal body 2, and as a result, the effect of suppressing water infiltration can be further improved.

  In addition, it is good also as providing a convex part (concave part) in the internal peripheral surface of the code | cord | chord rubber member 6, and in providing a convex part (concave part), it is protrusion part PL1 in at least one part of the site | part corresponding to the said convex part. , PL2 may not be present. In this case, it is possible to more effectively prevent water from entering between the cord-side rubber member 6 and the terminal body 2.

  (C) In the above embodiment, the annular protrusions PL3, PL4 are present on the surfaces of the engaging parts 23, 24, but the positions of the annular protrusions PL3, PL4 are not limited to this. Therefore, for example, as shown in FIG. 7, an annular protrusion PL <b> 3 may be provided on the first one end side of the first engagement portion 23. Further, the annular protrusion PL4 may be provided on the second end side with respect to the second engagement portion 24.

  (D) In the above embodiment, the terminal body 2 has a shape that bends at a substantially intermediate portion. However, as shown in FIG. 8, the plug body 1A has a linear terminal body 9 that extends along the axis CL3. On the other hand, the technical idea of the present invention may be applied. In the above embodiment, the terminal body 2 is bent at a substantially right angle, but the bending angle is not limited to this.

  (E) In the above embodiment, the other end side surface 34 of the plug side rubber member 3 and the other end side surface 64 of the cord side rubber member 6 are formed so as to extend in the radial direction, but as shown in FIG. The outer diameter continuously decreases with at least one of the other end side surface 34 of the plug side rubber member 3 and the other end side surface 64 of the cord side rubber member 6 (both in FIG. 9) facing the other end side. It is good also as making it incline to. In this case, it is possible to prevent water from being collected between the other end portions of the rubber members 3 and 6 and the terminal body 2 as much as possible, and thus more reliably prevent water from entering. In addition, it is good also as reducing the outer diameter of the other end side surfaces 34 and 64 stepwise toward the other end side, and also in this case, the penetration | invasion of water can be prevented still more reliably.

  (F) In the above-described embodiment, the outer diameter D1 of the first body constituting portion 21 at the first end side of the first engaging portion 23 and the second engaging portion of the second body constituting portion 22. The outer diameter D <b> 2 at the portion on the second one end side from 24 is constant. On the other hand, the outer diameter D1 may be decreased toward the first one end side, or the outer diameter D2 may be decreased toward the second one end side.

  (G) In the above embodiment, the electrical connection portion 5 is configured by electrically connecting the connector fitting 51, the contact spring 52, and the like, but the configuration of the electrical connection portion is limited to this. is not. In other words, any electrical connection may be used as long as the spark plug and the plug cord can be electrically connected. Therefore, the connector fitting 51 and the contact spring 53 may be electrically connected without providing the resistor 52. Moreover, it is good also as providing the conducting wire which electrically connects between a spark plug and a plug cord, and comprising an electrical connection part by the said conducting wire.

  (H) In the above embodiment, the surface on the first end side of the first engagement portion 23 and the surface on the second end side of the second engagement portion 24 are formed flat, but FIG. ), (B), an annular protrusion 27 projecting to the first end side is provided on the surface of the first engagement portion 23 on the first end side, or the first engagement portion 24 is You may provide the cyclic | annular protrusion 28 which protrudes in the 2nd one end side on the surface of one end side. In this case, the surface on the other end side of the engaging portions 23 and 24 (the back surface of the surface on which the ridge portions 27 and 28 are formed) and the engaged portions 33 and 63 can be more closely attached. Intrusion of water can be more reliably suppressed by both the contact portion and the protrusions 27 and 28. Moreover, although it is difficult to form the protrusions 27 and 28 projecting in a direction perpendicular to the radial direction of the terminal body 2 by the above-described conventional technique (a technique using two split molds), Thus, if the method is to move the one end side mold members M1, M2 in the direction perpendicular to the radial direction of the terminal body 2 and remove the one end side mold members M1, M2, the protrusions 27, 28 are difficult. It can be formed without.

  (I) In the said embodiment, although phenol resin is illustrated as resin which forms the terminal body 2, resin which forms the terminal body 2 is not limited to this. Therefore, for example, an unsaturated polyester resin or the like may be used. Further, as the resin forming the terminal body 2, a thermosetting resin is preferably used. However, any resin having excellent heat resistance may be used, and a thermoplastic resin having predetermined heat resistance (for example, PPS resin). It is also possible to use.

  (J) In the above embodiment, EPDM rubber and silicone rubber are exemplified as the rubber forming the plug-side rubber member 3 and the cord-side rubber member 6, but the rubber forming the plug-side rubber member 3 and the like is limited to this. Is not to be done. Therefore, for example, the plug-side rubber member 3 or the like may be formed using rubber having sufficient heat resistance against heat generated by the internal combustion engine, such as acrylic rubber.

  DESCRIPTION OF SYMBOLS 1 ... Plug cap, 2 ... Terminal body, 3 ... Plug side rubber member (rubber member), 5 ... Electrical connection part, 6 ... Cord side rubber member (rubber member), 23 ... 1st engaging part (engaging part) ), 24 ... 2nd engaging part (engaging part), 43 ... 1st insertion part (insertion part), 44 ... 2nd insertion part (insertion part), PL1, PL2 ... Projection part, PL3, PL4 ... Circular projection Part, M1... First end side mold member, M2... Second end side mold member, MO.

Claims (9)

An electrical connection for electrically connecting the spark plug and the plug cord;
A terminal body provided on the outer peripheral side of the electrical connection part;
A cylindrical rubber member attached to one end of the terminal body and through which the spark plug or the plug cord is inserted;
The terminal body has a cylindrical insertion portion through which the spark plug or the plug cord is inserted at one end of the terminal body, and a plug cap in which a protrusion extending along the longitudinal direction of the terminal body is present on the outer peripheral surface of the terminal body Because
The plug cap according to claim 1, wherein at least a part of a portion of the outer peripheral surface of the terminal body covered with the rubber member does not have the protruding portion over the entire periphery. An electrical connection for electrically connecting the spark plug and the plug cord;
A terminal body provided on the outer peripheral side of the electrical connection part;
A cylindrical rubber member attached to one end of the terminal body and through which the spark plug or the plug cord is inserted;
The terminal body has a cylindrical insertion portion through which the spark plug or the plug cord is inserted at one end of the terminal body, and a plug cap in which a protrusion extending along the longitudinal direction of the terminal body is present on the outer peripheral surface of the terminal body Because
One end of the said terminal body is located in the one end side rather than the one end of the said projection part, The plug cap characterized by the above-mentioned.   3. The plug cap according to claim 1, wherein an annular protrusion that extends along a circumferential direction and contacts one end of the protrusion is formed on an outer peripheral surface of the terminal body.   The annular protrusion part extended along a circumferential direction is formed in the site | part covered with the said rubber member among the outer peripheral surfaces of the said terminal body, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. Plug cap.   The terminal body has, on the outer peripheral surface thereof, a convex engaging portion with which an inner peripheral portion of the rubber member is engaged at a position spaced from the one end to the other end by a predetermined distance. The plug cap according to claim 3 or 4, wherein the annular protrusion is formed on a surface of the portion. The terminal body has a convex engagement portion on the outer peripheral surface thereof at a position spaced from the one end to the other end by a predetermined distance,
6. The terminal body according to claim 1, wherein an outer diameter of a part of the terminal body that is closer to one end than the engaging portion is constant or is made smaller toward the one end. Plug cap. On the inner peripheral surface of the rubber member, at least one annular convex portion is formed at a portion that contacts the outer peripheral surface of the terminal body,
Wherein the part of the portion corresponding to the convex portion of the outer peripheral surface of the terminal body, the plug cap according to any one of claims 1 to 6, characterized in that the protrusion does not exist. An electrical connection for electrically connecting the spark plug and the plug cord;
A terminal body provided on the outer peripheral side of the electrical connection portion,
The terminal body is a method of manufacturing a plug cap having a cylindrical insertion part through which the spark plug or the plug cord is inserted at one end of the terminal body,
Including a mold forming step of forming the terminal body by mold molding;
In the mold forming step, a molding die including a plurality of mold members, including at least one end side mold member for molding at least a part of one end side portion of the outer peripheral surface of the terminal body. Used,
The mold forming step
A mold closing step of closing the molding die;
A forming step of forming the terminal body by filling a material for forming the terminal body in a cavity portion provided inside the molding die and having a shape corresponding to the outer shape of the terminal body;
A mold opening step of opening the molding die and taking out the terminal body,
In the mold opening step, the one end side mold member and the terminal body are separated in a direction perpendicular to the radial direction of the terminal body. The terminal body has a convex engagement portion on the outer peripheral surface thereof at a position spaced from the one end to the other end by a predetermined distance,
The plug cap manufacturing method according to claim 8, wherein a portion on one end side from the engagement portion is formed by the one end side mold member.

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