JP2007177645A - Plug cap mounting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plug cap mounting structure allowing reduction in the diameter of a part of the plug cap while maintaining stability in support of the plug cap for disposing an ignition plug close to an engine side. <P>SOLUTION: In a main body part 64, a plate like extension part 63 is provided to an outer shell part of the plug cap 60 connected to the ignition plug 43, and an end of a cylinder head cover 49 is provided with a ring-like engagement projection 53 for supporting the extension part 63. Thereby, because there are two supporting locations of the plug cap 60 and stability is enhanced, the diameter of the main body 64 can be reduced to bring the ignition plug 43 close to the engine side. In the proximity of the extension part 63, a grip part 62 is provided for facilitating the attachment/detachment of the plug cap 60. Further, by switching the extension part 63 with a plate-like member having a through-hole, and switching the engagement member 59 with an engagement projection and two engagement plates, a structure with the engagement projection engaged in the through-hole, and engagement plates made to abut on both side faces of the plate-like member can be also obtained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plug cap mounting structure, and in particular, a plug cap mounting structure capable of arranging a spark plug closer to the engine side while reducing the diameter of a part of the plug cap while maintaining the support stability of the plug cap. About.

  2. Description of the Related Art Conventionally, attempts have been made to increase the rigidity of a plug cap by devising an internal structure in a plug cap for insulating and protecting a high voltage supply unit that applies a high voltage to an ignition plug of an engine.

Patent Document 1 discloses a plug cap in which an outer shell is formed of an elastic polymer material such as rubber, and a polymer material harder than the elastic polymer material is disposed inside the outer shell as a reinforcing material. Has been.
JP 2002-151231 A

  In recent years, there is an increasing demand for downsizing an engine room of a motorcycle or the like in order to expand passenger space. Accordingly, there is a demand for reducing the outer diameter of the cylindrical portion as much as possible in the plug cap disposed in the vicinity of the engine. In particular, in a SOHC engine, a camshaft and a rocker arm are arranged right above the combustion chamber, so that the spark plug is inserted from an obliquely upward position rather than directly above the fuel chamber at a position close to the side wall of the cylinder head. However, if the plug cap can be made smaller in diameter, it is possible to bring the tip of the spark plug as close as possible to the center of the combustion chamber and to bring the position of the combustion chamber and spark plug closer to the ideal shape and position. . However, for example, in the plug cap disclosed in Patent Document 1, if the hard polymer material as the reinforcing agent is removed to reduce the diameter of the plug cap, the durability is lowered.

  The object of the present invention is to solve the above-mentioned problems of the prior art, reduce the diameter of a part of the plug cap while maintaining the stability of the support of the plug cap, and attach the spark cap closer to the engine side. It is to provide a structure.

  In order to achieve the above-described object, the present invention provides an ignition plug that is close to a cylinder side wall of an engine and is inserted obliquely into a combustion chamber, a cord that supplies electric power to the ignition plug, and the ignition plug. A plug cap mounting structure that is disposed between the cords and includes the spark plug and a plug cap that is connected to the cord, an extension provided in an outer shell of the plug cap, and a component of the engine There is a first feature in that it is provided with an engaging member that engages with the extending portion.

  The engine component is a cylinder head cover, the extension is a plate-like member extending outward in the circumferential direction of the cylindrical portion of the plug cap, and the engagement member is the cylinder A second feature is that the protrusion is a ring-shaped protrusion having a hole that protrudes from the head cover and supports the end face of the plate-like member.

  Further, the plate member has a third feature in that it is formed in an approximately elliptical shape and a plurality of convex portions are provided on the end surface.

  The engine component is a cylinder head cover, and the extending portion extends outward in the circumferential direction of the cylindrical portion of the plug cap and is provided with a through hole penetrating in the thickness direction. Two engaging plates that protrude from the cylinder head cover and that are in contact with or substantially in contact with the two side end surfaces of the extending portion. There is a fourth feature in that it is composed of:

  Furthermore, the plug cap has a fifth feature in that a grip portion curved with respect to the longitudinal direction is provided on a substantially extended line of the spark plug in the longitudinal direction.

  According to the first aspect of the present invention, by engaging the extension part of the plug cap and the engaging member provided in the engine component, the support part to the engine side of the plug cap becomes two places. The stability of the support can be increased. In addition, according to the increased support stability, a part of the reinforcing agent made of a hard polymer material can be removed, and the plug cap can be reduced in diameter. Furthermore, as the diameter of the plug cap is reduced, the spark plug can be brought closer to the engine side, so that the degree of design freedom around the engine can be increased.

  According to the second invention, the plug cap is provided with a plate-like member, and the ring-like protrusion is provided on the cylinder head cover, which is easier to mold than the cylinder head, etc. Can be more stably supported.

  According to the third invention, the engagement position between the extension portion and the engagement portion is stably determined by forming the engagement member side also in a substantially elliptical shape. Further, by providing a plurality of convex portions, the extending portion and the engaging portion engage with each other at a plurality of points or lines, so that the plug cap can be supported more stably and attachment / detachment work becomes easy. .

  According to the fourth invention, a plate-like member having a through hole is provided in the plug cap, and only one engagement protrusion and two engagement plates are provided on a cylinder head cover that is easier to mold than a cylinder head or the like. The plug cap can be prevented from shaking and the plug cap can be supported more stably.

  According to the fifth aspect of the present invention, since the grip portion on which a tool, a finger, or the like can be hooked is provided on the extension line in the longitudinal direction of the spark plug, the work of pulling out the plug cap from the spark plug is facilitated.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of an embodiment of a motorcycle to which the present invention is applied. The motorcycle 1 is a scooter type motorcycle having a unit swing type power unit incorporating a continuously variable transmission. A head pipe 4 is fixedly coupled to a pair of left and right main frames 8 covered by a vehicle body cover 23 in front of the vehicle body together with a gusset 6 as a joint reinforcing member. A front wheel WF is rotatably supported at the lower end of the front fork 5. The front fork 5 is steerable by a handle bar 3 connected to a stem shaft 2 that is rotatably supported inside the cylindrical head pipe 4. A pair of left and right handle grips 3 a gripped by an occupant are attached to the handle bar 3. The main frame 8 is provided with a cross member 9 that is arranged in the vehicle width direction and connects the left and right pipe members. A single center frame 7 is provided on the rear side of the vehicle body. ing. The center frame 7 adjacent to the leg shield 24 disposed in front of the passenger's legs is connected to a pair of left and right connecting frames 13 below the vehicle body. The connection portion and the main frame 8 are connected to a pair of left and right links. They are connected by a pipe member 14. A guard pipe 15 that protects the radiator 25 is connected in the vicinity of the pipe member 14. The end of the connecting frame 13 on the vehicle body rear side is connected to a side frame 10 formed integrally with the main frame 8.

  A pivot shaft 17 serving as a rotation shaft of a power unit 22 described later is provided between a rising frame portion 11 formed integrally with the side frame 10 and a rear subframe 18 connected to the rising frame portion 11. A pair of left and right pivot plates 16 that are pivotally supported are attached. A seat rail portion 12 that supports a storage box 30 and a fuel tank 32 disposed below a seat 31 on which an occupant sits is connected above and behind the rising frame portion 11. A power unit 22 including an engine 21, a carburetor 27, and an air cleaner box 26 is supported by a pivot shaft 20 on a link mechanism 19 that is rotatably supported by the pivot shaft 17. The power unit 22 is swingable with the pivot shaft 17 as a rotation shaft by being suspended by a rear cushion 28 attached to the seat rail portion 12, and at the rear end thereof as a drive wheel. A rear wheel WR is rotatably supported.

  FIG. 2 is a sectional view of the engine 21 to which the plug cap mounting structure according to the present invention is applied. The 4-cycle single-cylinder engine 21 is an SOHC (single-over-head camshaft) type two-valve unit that uses a rocker arm. In the figure, the engine 21 is only above the crankshaft 40 housed in the crankcase 34. Is shown. The end of the crankshaft 40, which is the output shaft, is composed of a drive-side movable pulley half 51, a drive-side fixed pulley half 52, and an endless V-belt 50. The power of the engine 21 can be arbitrarily shifted to the rear wheels WR. A continuously variable transmission that transmits by ratio is installed. A cylinder block 39 is attached to the crankcase 34, and a cylindrical piston 36 slidable inside a sleeve 38 accommodated in the cylinder block 39 is connected to the crankshaft 40 via a connecting rod 37. . A cylinder head 41 is fixed to the upper end of the cylinder block 39, and the cylinder head 41, the cylinder block 39, and the piston 36 form a combustion chamber 42 for burning the air-fuel mixture. The cylinder head 41 is rotatably supported by a camshaft 44 for driving a rocker arm 47 that opens and closes an intake / exhaust valve (not shown). The camshaft 44 and a cam sprocket 45 fixedly attached to one end of the camshaft 44 are driven to rotate by an endless cam chain 46 connected to the crankshaft 40. A cylinder head cover 49 is disposed above the rocker arm 47 and the cam sprocket 45.

  A spark plug 43 for igniting the air-fuel mixture compressed in the combustion chamber 42 is detachably attached to the cylinder head 41. The spark plug 43 is disposed so that the electrode 43a at the tip thereof is seen through the combustion chamber 42, and the insulator 43b and the terminal 43c are installed close to the outer wall of the cylinder head 41. Here, the spark plug 43 is attached with a plug cap (not shown) for insulating protection of a high voltage supply section for applying a high voltage necessary for ignition. The plug cap is connected to the terminal 43 and the insulator. Since it is configured to cover most of the portion 43 b, if the outer diameter of this portion is large, it is difficult to dispose the spark plug 43 toward the center side of the cylinder head 41. That is, it is difficult to reduce the size of the engine room, or to reduce the mounting inclination angle of the spark plug 43 with respect to the combustion chamber 42 to bring the combustion chamber shape closer to an ideal hemisphere. In order to solve this problem, the plug cap attachment structure according to the present invention is applied to the plug cap attached to the plug 43 and the cylinder head cover 49.

  FIG. 3 is a perspective view of the cylinder head 41 and the cylinder head cover 49 to which the plug cap mounting structure according to one embodiment of the present invention is applied. The same reference numerals as those described above denote the same or equivalent parts as described above. The spark plug 43 is disposed in the recess 54 of the cylinder head 41 in which the intake port 53 is formed. A plug hole (not shown) in which a female screw is formed is provided at the bottom of the recess 54, and both are coupled by being screwed with a male screw formed in the plug 43. The plug 43 is attached with a plug cap 60 for connecting a high tension cord 65 for supplying power and the terminal 43c (see FIG. 2), and for insulating and protecting the connecting portion. The plug cap 60 includes a cylindrical main body portion 64 that covers the lever portion 43b and the terminal 43c of the spark plug 43, an extension portion 63 projecting outward in the circumferential direction of the main body portion 64, and the high tension cord 65. The connecting portion 61 and a grip portion 62 that functions as a handle when the plug cap 60 is removed from the spark plug 43 are integrally formed.

  The cylinder head cover 49 has a mounting bolt 56 for supporting a guide stay 55 for arranging a wiring cord (not shown) at an appropriate position, and a cylinder head 41 for supporting the cylinder head cover 49 to the cylinder head 41 in a fixed manner. Mounting bolts 57 and 58 are attached. At the end of the cylinder head cover 49, a ring-shaped engagement member 59 that is engaged with the extension 63 of the plug cap 60 is formed. A plug cap mounting structure according to an embodiment of the present invention includes an engagement member 59 formed on the cylinder head cover 49 and a plug cap 60 having an extending portion 63.

  FIG. 4 is a top view of the cylinder head cover 49 according to one embodiment of the present invention. The engagement member 59 is configured such that a support hole 59 a for supporting the extension portion 63 is formed at one end portion of the cylinder head cover 49 by a thin plate integral with the cylinder head cover 49. The engaging member 59 engages with the extending portion 63 so that the plug cap 60 is stably supported by the cylinder head cover 49 when the plug cap 60 and the spark plug 43 are connected. It is comprised so that. In the present embodiment, the inner peripheral surface of the engaging member 59 is a smooth surface, but a protrusion, a groove, or the like may be formed so as to be easily engaged with the extending portion 63. The cylinder head cover 49 is formed with through holes 57a and 58a into which the mounting bolts 57 and 58 are inserted.

  FIG. 5 is a front view of the plug cap 60. The same reference numerals as those described above denote the same or equivalent parts as described above. As described above, the plug cap 60 according to the present embodiment is formed with the extending portion 63 as a plate-like member having a plurality of convex portions 63a, and when the plug 43 and the plug cap 60 are connected to each other. Further, the outer peripheral surface of the extending portion 63 and the inner peripheral surface of the engaging member 59 are configured to be engaged with each other. Therefore, the plug cap 60 is supported on the engine side at the two locations of the main body portion 64 and the extension portion 63, and can be supported more stably than the conventional method supported only by the main body portion 64. It becomes. In the present embodiment, the stability is enhanced by the two-point support, so that the outer diameter of the main body 64 can be made thinner than that of the conventional method. The grip portion 62 formed in the vicinity of the connection portion 61 has a curved shape with an angle of about 90 degrees with respect to the main body portion 64 so that a tool, a finger or the like can be easily pulled. In addition, the extending portion 63 has a substantially elliptical shape, and is configured such that the engagement position is stably determined when engaged with the engagement member 59 having a shape corresponding thereto. Yes.

  FIG. 6 is a view in the A direction of FIG. The same reference numerals as those described above denote the same or equivalent parts as described above. The dimension of the extending portion 63 in the thickness direction is formed to be substantially the same as the height of the engaging portion 59 of the cylinder head cover 49. Further, the extension part 63 is set to have a larger diameter on the connection part 61 side than the main body part 64 side, and on the other hand, the engagement member 59 has a mortar shape corresponding thereto, thereby the extension part 63. When the part 63 is engaged with the engaging member 59, it is configured to be stably supported at a predetermined position. The plurality of convex portions 63a have a role of making the engagement position easier to be determined by contacting the inner peripheral surface of the engagement member 59 with a plurality of lines. Further, the convex portion 63a also has a role of making it difficult to transmit engine vibration to the main body portion 64. In addition to the semi-cylindrical shape shown in the figure, the convex portion 63a has a triangular prism shape or the like, and the number of installation is arbitrarily selected. be able to. Further, the extending portion 63 may be configured not to provide the convex portion 63a but to be engaged with the inner peripheral portion of the engaging member 59 on the entire peripheral surface thereof, or to be provided with a plurality of concave portions. .

  FIG. 7 a is a side view of the plug cap 60. The same reference numerals as those described above denote the same or equivalent parts as described above. The outer shell portion of the plug cap 60 in this embodiment is, for example, rubber from the connecting portion 61 having the insertion port 61a of the high tension cord 65 (see FIG. 3) to the extending portion 63 and the main body portion 64. It is integrally formed of the same material made of an elastic polymer material such as. The extending portion 63 is formed at a predetermined angle with respect to the longitudinal direction of the main body portion 64 in order to match the shape of the engaging member 59. The outer diameter of the main body 64 into which the spark plug 43 is inserted is such that the plug cap 60 is stably supported by the engagement relationship between the extension 63 and the engagement member 59. Along with this, the diameter has been significantly reduced compared to the conventional method.

  FIG. 7 b is a cross-sectional view of the plug cap 60. The same reference numerals as those described above denote the same or equivalent parts as described above. In the present embodiment, the diameter of the main body portion 64 is reduced by removing the reinforcing agent provided in the portion where the lever portion 43b (see FIG. 2) is inserted in the conventional method. A cord setting screw 66 connected to the high tension cord 65 is disposed at the bottom of the insertion port 61a. The electrode plate 67 connected to the cord setting screw 66 is a terminal of the spark plug 43. 43c (refer FIG. 2) and the electrode 68 which contact | abuts are connected. In this embodiment, the electrode plate 67 and the electrode 68 are covered with a hard insulator 69 made of synthetic resin or the like, and the vicinity of the insertion hole 64a of the spark plug 43 is made of only an elastic polymer material such as rubber. Is possible.

  FIG. 8 is a perspective view of the cylinder head 88 and the cylinder head cover 70 to which the plug cap mounting structure according to the second embodiment of the present invention is applied. Also in the present embodiment, the configuration in which the spark plug 43 is disposed in the recess 78 of the cylinder head 88 in which the intake port 79 is formed is the same as in the above-described embodiment. The spark plug 43 is connected with a high tension cord 85 and the terminal 43c (see FIG. 2), and a plug cap 80 is attached to insulate and protect the connecting portion. The plug cap 80 includes a cylindrical main body portion 84 covering the lever portion 43b and the terminal 43c of the spark plug 43, a plate-like extension portion 82 projecting outward in the circumferential direction of the main body portion 84, and the high tension. The connection portion 81 with the cord 85 is integrally formed. Further, a through hole 83 through which an engaging projection 77 formed on the cylinder head cover 70 passes is formed at the approximate center of the extending portion 82.

  The cylinder head cover 70 has a mounting bolt 72 for supporting a guide stay 71 for arranging a wiring cord (not shown) at an appropriate position, and a cylinder head 88 for fixedly supporting the cylinder head cover 70 to the cylinder head 88. Attachment bolts 73 and 74 are attached. The engagement protrusion 77 and the plate-like first engagement plate 75 and the second engagement plate 76 that sandwich the extension portion 82 are formed at one end of the cylinder head cover 70. The plug cap mounting structure according to the present embodiment includes the extending portion 82, the engagement protrusion 77, the first engagement plate 75, and the second engagement plate 76.

  FIG. 9 is a top view of a cylinder head cover 70 according to the second embodiment of the present invention. The engagement protrusion 77, the first engagement plate 75, and the second engagement plate 76 are integrally formed at one end of the cylinder head cover 70. When the extension portion 82 is engaged with the engagement protrusion 77, the first engagement plate 75, and the second engagement plate 76, the plug cap 80 is connected to the spark plug 43. 80 is configured to be stably supported by the cylinder head 88. The cylinder head cover 70 is formed with through holes 73a and 74a into which the mounting bolts 73 and 74 are inserted.

  FIG. 10 is a partially enlarged view of the cylinder head cover 70. The same reference numerals as those described above denote the same or equivalent parts as described above. The first engagement plate 75 and the second engagement plate 76 that abut or substantially abut so as to sandwich the extending portion 82 of the plug cap 80 from both sides are the cylinder head 88 (see FIG. 8), the cylinder head cover 70, and the like. Are arranged substantially perpendicular to the dividing plane. In addition, the engagement protrusion 77 supported by the rib 77b formed in the same direction as the first engagement plate 75 and the second engagement plate 76 is substantially the same as the mounting angle of the spark plug 43, and When the plug 43 and the plug cap 80 are connected, the engaging protrusion 77 and the through hole 83 are configured to engage smoothly.

  FIG. 11 is a top view of the plug cap 80. The same reference numerals as those described above denote the same or equivalent parts as described above. The extending portion 82 has a shape having a substantially straight portion so as to be engaged with the side surface portions of the first engaging plate 75 and the second engaging plate 76, and has an oval through hole at a substantially center thereof. 83 is formed. Also in the present embodiment, a grip portion that functions as a handle when the plug cap 80 is removed from the spark plug 43 can be integrally formed in the vicinity of the connection portion 81.

  FIG. 12 is a partially enlarged view of the plug cap 80. The same reference numerals as those described above denote the same or equivalent parts as described above. The outer shell member of the plug cap 80 in this embodiment is, for example, rubber from the connecting portion 81 having the insertion port 81a of the high tension cord 85 (see FIG. 8) to the extending portion 82 and the main body portion 84. It is integrally formed of the same material made of an elastic polymer material such as. The outer diameter of the main body 84 into which the spark plug 43 is inserted is greatly reduced compared to the conventional method by the plug cap 80 being stably supported by the plug cap mounting structure as described above. Yes.

  FIG. 13 a is a side view of the plug cap 80. The same reference numerals as those described above denote the same or equivalent parts as described above. In the present embodiment, the engagement portion 82 is formed in a direction perpendicular to the longitudinal direction of the main body portion 84, thereby simplifying the shape and reducing the production process. This is because the angle at which the engagement protrusion 77 (see FIG. 10) extends from the cylinder head cover 70 matches the mounting angle of the spark plug 43, and the extension cap 82 is ignited by the plug cap 80. When connected to the plug 43, it is stably supported by both side surfaces of the first engagement plate 75 and the second engagement plate 76, and the engagement protrusions 77 and ribs 77b.

  FIG. 13 b is a cross-sectional view of the plug cap 80. The same reference numerals as those described above denote the same or equivalent parts as described above. In the present embodiment, the diameter of the main body portion 84 is reduced by removing the reinforcing agent provided in the portion where the lever portion 43b is inserted in the conventional method. A cord setting screw 89 for connecting to the high tension cord 85 (see FIG. 8) is disposed at the bottom of the insertion port 81a, and an electrode plate 86 connected to the cord setting screw 89 is The electrode 87 is in contact with the terminal 43c (see FIG. 2) of the spark plug 43. Also in this embodiment, the electrode plate 86 is covered with the electrode 87 with a hard insulator 90 made of synthetic resin or the like, and the vicinity of the insertion hole 84a of the spark plug 43 is made of only an elastic polymer material such as rubber. Making it possible.

  As described above, according to the plug cap mounting structure according to the present invention, the extension portion provided in the plug cap and the engagement member provided in the cylinder head cover are engaged, so that the plug cap is moved to the engine side. The support portion of the plug cap is provided in two places, so that the stability of supporting the plug cap can be improved. Further, in response to the improvement in the stability of the support, a part of the reinforcing agent made of a hard polymer material can be removed to reduce the diameter of the plug cap. Further, as the plug cap is reduced in diameter, the spark plug can be brought closer to the engine side, so that the degree of freedom in design around the engine can be increased.

  Of course, the shape of the plug cap and cylinder head cover, the internal structure of the plug cap, and the like are not limited to the above-described embodiment, and various modifications are possible. For example, the engagement member provided in the cylinder head cover can be configured as a separate type, or the engagement member on the cylinder head cover side can be formed in a concave shape.

1 is a side view of a motorcycle to which a plug cap mounting structure according to an embodiment of the present invention is applied. It is sectional drawing of the engine which concerns on one Embodiment of this invention. It is a perspective view of a cylinder head and a cylinder head cover concerning one embodiment of the present invention. It is a top view of the cylinder head cover concerning one embodiment of the present invention. It is a front view of the plug cap concerning one embodiment of the present invention. FIG. 6 is a view in the A direction of FIG. 5. It is a side view of the plug cap concerning one embodiment of the present invention. It is sectional drawing of the plug cap which concerns on one Embodiment of this invention. It is a perspective view of a cylinder head and a cylinder head cover concerning a 2nd embodiment of the present invention. It is a top view of a cylinder head cover concerning a 2nd embodiment of the present invention. It is a perspective view of a cylinder head cover concerning a 2nd embodiment of the present invention. It is a top view of the plug cap which concerns on 2nd Embodiment of this invention. It is a partial enlarged view of the plug cap which concerns on 2nd Embodiment of this invention. It is a side view of the plug cap which concerns on 2nd Embodiment of this invention. It is sectional drawing of the plug cap which concerns on 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 41 ... Cylinder head, 43 ... Spark plug, 49 ... Cylinder head cover, 53 ... Intake port, 54 ... Recess, 59 ... Engagement protrusion, 60 ... Plug cap, 61 ... Connection part, 62 ... Gripping part, 63 ... Extension part 64 ... main body, 65 ... high tension cord

Claims (5)

A spark plug that is inserted into the combustion chamber at an angle close to the side wall of the cylinder head of the engine,
A cord for supplying power to the spark plug;
In the plug cap mounting structure that is disposed between the spark plug and the cord and includes the spark plug and a plug cap connected to the cord,
An extending portion provided in an outer shell portion of the plug cap;
A plug cap mounting structure comprising an engagement member provided on a component of the engine and engaged with the extending portion. The engine component is a cylinder head cover,
The extending portion is a plate-like member extending outward in the circumferential direction of the cylindrical portion of the plug cap,
2. The plug cap mounting structure according to claim 1, wherein the engagement member is a ring-shaped protrusion that protrudes from the cylinder head cover and has a hole portion that supports an end surface of the plate-like member.   The plug cap mounting structure according to claim 2, wherein the plate-like member is formed in a substantially elliptical shape, and a plurality of convex portions are provided on an end surface thereof. The engine component is a cylinder head cover,
The extending portion is a plate-like member provided with a through hole extending outward in the circumferential direction of the cylindrical portion of the plug cap and penetrating in the thickness direction.
The engagement member includes one engagement protrusion that protrudes from the cylinder head cover and penetrates the through hole, and two engagement plates that abut or substantially abut against the two side end surfaces of the extension portion. The plug cap mounting structure according to claim 1, wherein:   5. The plug cap according to claim 1, wherein a grip portion that is curved with respect to the longitudinal direction is provided on a substantially extended line in the longitudinal direction of the spark plug. Plug cap mounting structure.

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