JPH0433394Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cylinder head structure for an engine mounted on a motorcycle.

[Conventional technology]

The heat value of the spark plug tends to change depending on the temperature of the seat surface to which it is fastened, and changes in the heat value tend to cause abnormal ignition in the combustion chamber. Especially if the cooling is poor,
This is equivalent to a lower heat value, making it easier to cause abnormal ignition.

For this reason, as shown in Japanese Utility Model Application Laid-open No. 57-89840, a vehicle is known in which an air passage surrounding the ignition plug is formed by a vertical wall that opens on the side of the vehicle body.

However, with such a configuration, water, mud, etc. tend to accumulate around the seat surface of the spark plug when the car is washed or on rainy days, and this tends to induce leakage of the spark plug, resulting in a misfire.

Therefore, Japanese Unexamined Patent Publication No. 125315/1983
As disclosed in Japanese Patent No. 54542, it is known that a standing wall is formed around the spark plug in a cylindrical shape, and a cap is placed on the standing wall to take waterproof measures.

[The problem that the idea aims to solve]

However, in such a configuration, the original cooling effect of cooling the spark plug is lost.
Furthermore, even if the cap is removed, no air passage is formed because the vertical wall is cylindrical, and although accumulated water can be removed through the drain hole, the water drain hole is narrow, so cooling air is No flow occurs.

Therefore, in view of the above-mentioned circumstances, the purpose of this invention is to allow the area around the ignition plug to be easily cooled while driving, to drain water from the area around the seat of the ignition plug, and to maintain a constant heat value around the seat of the ignition plug. To provide a cylinder head structure for a motorcycle engine that is easy to dry.

[Means to solve the problem]

In this invention, a cylinder head is formed with a vertical wall that opens on the side of the vehicle body around the spark plug seating surface and is tilted toward the front of the vehicle body, and an exhaust passage is formed on the lower side of the cylinder head, and an intake passage is formed on the upper side of the cylinder head. In a cylinder head of a motorcycle engine, the cylinder head of a motorcycle engine is provided with an air passage extending from above the cylinder head toward the side of the vehicle body and surrounding the ignition plug,
The cylinder head is characterized in that a water drain hole is formed in the cylinder head, penetrating from the vicinity of the spark plug seating surface downward to the exhaust side.

[Effect]

Therefore, with the above configuration, cooling air flows through the air passage surrounding the ignition plug during driving, and the area around the ignition plug is easily cooled. Water drains well from around the seat of the spark plug, and during driving, relatively high temperature air from the exhaust side is sucked in through the drain hole due to the ventilly effect, and this air is constantly drawn around the seat of the spark plug. The heat value around the seat of the spark plug can be maintained constant, and especially when driving in the rain, the area around the seat of the spark plug can be quickly dried and leakage of the spark plug can be effectively prevented.

〔Example〕

Hereinafter, the present invention will be explained based on an illustrated embodiment.

FIG. 1 is a side view showing an example of a motorcycle equipped with a V-type engine, FIG. 2 is an enlarged side view of the V-type engine shown in FIG. 1, FIG. 3 is a cross-sectional view of FIG. The figure is a partially cutaway view taken along the - arrow in FIG. 2.

In FIG. 1, body frame 2 constituting the body of motorcycle 1 has a main frame 4 extending rearward from the upper part of head pipe 3, and a downtube 5 extending diagonally downward rearward from the lower part of head pipe 3 and approximately horizontal at its lower part, whose tips are connected at rear fork pivot 6, and main frame 4 and downtube 5 are connected and reinforced by sub-main frame 7 to form a front frame, seat rail 8 extends rearward from approximately the middle of main frame 4, and rear stay 9 extends diagonally upward rearward from rear fork pivot 6, and the tips of both are connected together and sub-stay 10 is connected between seat rail 8 and main frame 4 for reinforcement to form a rear frame.
Furthermore, reference numeral 11 denotes a fuel tank and 12 denotes a seat.

For example, the front frame composed of a head pipe 3, a main frame 4, a down tube 5, and a sub-main frame 7 has a V-type engine 2.
0 is installed. When the V-type engine 20 is installed as shown, the front cylinder 30 is tilted forward.
The rear cylinders 60 are arranged so as to be tilted backward in the longitudinal direction of the vehicle body.

As shown in FIG. 2, the front cylinder 30 includes a cylinder head 32 attached to the upper part of a cylinder block 31 that is integrally formed with the crankcase 21 of the V-type engine 20 and tilted forward, and a cylinder head 32 attached to the upper part of the cylinder head 32. Attached head cover 33
It is made up of.

A combustion chamber 34 is formed approximately at the center of one side of the cylinder block 31, and a spark plug 35 is attached to the cylinder head 32 at a position corresponding to the upper part of the combustion chamber 34. In the lower part of the cylinder head 32, an intake passage 36 is provided on the upper side facing rearward, and an exhaust passage 37 is provided on the lower side facing forward.

Around the seat surface of the ignition plug 35 of the cylinder head 32, vertical walls 38 and 39 are formed extending in the left-right direction of the vehicle body at the front and rear sides of the ignition plug 35, respectively.
The spark plug 3 is connected to the vertical walls 38 and 39.
5 and a vertical wall 40 extending in the longitudinal direction of the vehicle body toward the center of the cylinder head 32, the cylinder head 32 is surrounded by a vertical wall 40 extending in the longitudinal direction of the vehicle body. An air passage 50 is formed surrounding the spark plug.

As shown in FIGS. 3 and 4, the upper part of the cylinder head 32 has cam shafts 41 and 42 and a chain sprocket 4 that is pivotally attached to the shafts 41 and 42.
3 and 44 and a housing part 46 for storing a chain 45 wound around both sprockets 43 and 44.

Further, a plug wrench 9 for attaching and detaching the spark plug 35 is provided around the seat surface of the spark plug 35 of the cylinder head 32 surrounded by the vertical walls 38, 39, and 40.
A regulating hole 47 into which the 0 is inserted is recessed, and a female threaded hole 48 communicating with the combustion chamber 34 is bored in the lower part of the regulating hole 47, and the regulating hole 47 and the female threaded hole 48 are surrounded by a water jacket 49. has been done. The air passage 50 above the regulating hole portion 47 has an arcuate cross section and also serves as a guide portion for guiding the plug wrench 90.

Furthermore, a drain hole 51 is formed in the cylinder head 32 and extends downward from the exhaust side from near the seating surface of the spark plug 35. In this embodiment, a drain hole 51 is formed from the bottom of the regulating hole 47 diagonally downward toward the front. It passes through between the air fins 52.

Therefore, the penetration path of the water drain hole 51 is shortened compared to the conventional one, and cooling air flows through the air passage 50 surrounding the spark plug during driving, making it easier to cool the spark plug and the spark plug. Water can be efficiently drained from around the seat surface of the spark plug 35 through the water drain hole 51 that penetrates from the vicinity of the seat surface of the spark plug 35 downward to the exhaust side.
Relatively high-temperature air from the exhaust side is sucked in through the water drain hole 51, and this air constantly hits the area around the seat of the spark plug 35, maintaining a constant heat value around the seat of the spark plug 35, especially when driving in the rain. Now, quickly dry the area around the seat of the spark plug 35, and
can effectively prevent leakage of spark plug 3.
The occurrence of rust around the seat surface of No. 5 can be suppressed as much as possible.

On the other hand, the rear cylinder 60 includes, as shown in FIG. head cover 63 attached to
It is constructed in the same manner as the front cylinder 30 except for the mounting positions of the intake passage and exhaust passage and the penetrating direction of the drain hole.

That is, in the lower part of the cylinder head 62, an intake passage 66 is provided on the upper side facing forward, and an exhaust passage 67 is provided on the lower side facing rearward.

Around the seat surface of the spark plug 65 of the cylinder head 62, vertical walls 68 and 69 are formed extending in the left-right direction of the vehicle body at the front and rear sides of the spark plug 65, respectively.
The spark plug 6 is connected to the vertical walls 68 and 69.
5 and a vertical wall 70 extending in the longitudinal direction of the vehicle body toward the center of the cylinder head 62, the cylinder head 62 is surrounded by a vertical wall 70 extending in the longitudinal direction of the vehicle body. An air passage 80 is formed surrounding the spark plug.

In addition, a restriction hole portion 77 and a threaded hole 78 are formed around the seating surface of the spark plug 65 of the cylinder head 62, which is surrounded by the vertical walls 68, 69, 70, and the air passage 80 above the restriction hole portion 77 has an arc-shaped cross section and also serves as a guide portion for guiding a plug wrench.

Furthermore, a drain hole 81 is formed in the cylinder head 62 and extends downward from the exhaust side from near the seating surface of the spark plug 65. In this embodiment, a drain hole 81 is formed from the bottom of the regulating hole 77 diagonally downward toward the front. It penetrates between the air fins 82.

Therefore, as in the case of the front cylinder 30, the passage through the drain hole 81 is shortened compared to the conventional one, and cooling air flows through the air passage 80 surrounding the spark plug during driving, preventing ignition. The area around the spark plug 65 can be easily cooled, and water can be efficiently drained from the area around the seat surface of the spark plug 65 through the water drain hole 81 that penetrates from the vicinity of the seat surface of the spark plug 65 downward on the exhaust side. , sucks relatively high temperature air from the exhaust side through the water drain hole 81,
This air constantly hits the area around the seat surface of the spark plug 65, maintaining the heat value around the seat surface of the spark plug 65 constant, and especially when driving in the rain, the area around the seat surface of the spark plug 65 quickly dries, preventing ignition. Leakage of the plug 65 can be effectively prevented, and the occurrence of rust around the seat surface of the ignition plug 65 can be suppressed as much as possible.

[Effect of idea]

As described above, the present invention has a cylinder head that has a vertical wall that opens on the side of the vehicle body around the spark plug seating surface and is inclined toward the front of the vehicle body, and an exhaust passage is formed on the lower side of the cylinder head and the exhaust passage is formed on the upper side of the cylinder head. An air intake passage is provided in each cylinder head, extending from above the cylinder head toward the side of the vehicle body to form an air passage surrounding the spark plug, and in the cylinder head, a drain hole is provided that penetrates from near the spark plug seating surface to below the exhaust side. , the cooling air flows through the air passage surrounding the ignition plug while driving, making it easier to cool the ignition plug area. Water drains well around the seat surface, and while driving, the ventilly effect draws in relatively high-temperature air from the exhaust side through the water drain hole, and this air constantly hits the area around the spark plug seat, causing the spark plug to dry. The heat value around the seat surface is maintained constant, and especially when driving in the rain, the area around the seat surface of the ignition plug can be quickly dried and leaks from the spark plug can be effectively prevented.

[Brief description of the drawings]

The figures show one embodiment of the present invention, in which Fig. 1 is a side view of a motorcycle equipped with a V-type engine, Fig. 2 is an enlarged side view of the V-type engine shown in Fig. 1,
FIG. 3 is a cross-sectional view taken in FIG. 2, and FIG. 4 is a partially cutaway view taken in the direction indicated by the arrow in FIG. 20... V-type engine, 30... Front cylinder, 32... Cylinder head, 35... Spark plug, 36... Intake passage, 37... Exhaust passage, 3
8, 39, 40... Standing wall, 50... Air passage, 5
1...Drain hole.

Claims (1)

[Scope of utility model registration request] A cylinder head having an upright wall opening on the side of the vehicle body around the spark plug seating surface is tilted toward the front of the vehicle body, and an exhaust passage is provided on the lower side of the cylinder head, and an intake passage is provided on the upper side of the cylinder head, In the cylinder head of a motorcycle engine, which forms an air passage that extends from above the cylinder head toward the side of the vehicle body and surrounds the ignition plug, water penetrates into the cylinder head from near the spark plug seating surface to the bottom of the exhaust side. A cylinder head structure for a motorcycle engine characterized by forming a punch hole.