JP2936076B2 - Cylinder head cooling device for motorcycle engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a motorcycle engine, and more particularly to a cylinder head cooling device for an air-cooled 4-cycle multi-cylinder engine.

(Prior art) In particular, in an air-cooled four-cycle DOHC engine mounted on a motorcycle, a pair of camshafts are provided on an upper portion of a cylinder head in such a manner that their axial directions coincide with the vehicle width direction and the longitudinal direction of the vehicle body. Although there is one that is parallel and spaced apart, in such an engine, a long cam cover in the vehicle width direction to cover the camshaft bulges in the vehicle longitudinal direction on the upper surface of the head cover. The head cover has a recessed space surrounded by the front and rear cam covers, and there is a problem that heat easily accumulates in this space.

Therefore, a wind guide is attached to the head cover, and the running wind is forcibly introduced into the concave space by the wind guide,
Thus, a cooling device that enhances the cooling performance of the cylinder head has been proposed (see Japanese Utility Model Laid-Open No. 52-60529).

(Problems to be Solved by the Invention) However, in the above-described conventional cooling device, the air guide is arranged such that most of the lower surface thereof is located more upstream in the direction of flow of the traveling wind. Due to the wind, the traveling wind cannot be efficiently introduced into the concave space of the head cover, and there is a problem that the cylinder head is not efficiently cooled.

Further, since the air guide is formed separately from the head cover, there is a problem that the appearance of the engine is impaired.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a cylinder head cooling device for a motorcycle engine that can efficiently cool a cylinder head and does not impair the appearance of the engine. To provide.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a head cover mounted on a vehicle body with a cylinder axis inclined forward and attached to a head cover attached to an upper portion of a cylinder head in a longitudinal direction of the vehicle body. A pair of cam cover portions that are parallel and spaced apart in the vehicle width direction, and extend in the vehicle front-rear direction so as to connect the pair of cam covers, and a height of the head cover from a mating surface with the cylinder head. In a cylinder head cooling device for a motorcycle engine integrally formed with a gear cover portion that is higher than the height of the cam cover portion, a space formed between the pair of front and rear cam cover portions of the head cover is formed laterally of the gear cover portion. And overlaps with the cam cover portion on the front side of the vehicle body in a direction perpendicular to the mating surface of the head cover with the cylinder head. In order to avoid this, at a position deviated to the rear of the vehicle body, a wind guide wing portion having an airfoil cross section through which traveling wind is to be introduced, and having a maximum height substantially equal to the height of the gear cover portion is provided. The lower surface is disposed above the space so as to be located lower in the flow direction of the traveling wind, and one end of the air guide blade is connected to a side surface of the gear cover, and According to the present invention, the lower surface of the air guide vane portion is located lower as the downstream side in the traveling wind flow direction. As a result, the traveling wind is efficiently introduced into the space by the air guide vanes and is used for cooling the cylinder head. Cools well. Since the air guide vanes have an airfoil cross section, the traveling wind flowing directly above the air guide vanes can be curved downward after passing through the air guide vanes, and the cam cover on the rear side of the vehicle body located behind the air guide vanes. The traveling wind is also guided to the section, and the cam cover can be cooled by the traveling wind.

Further, since the air guide wing is formed integrally with the head cover, the appearance of the engine is not impaired by the air guide wing.

Further, the air guide wing portion having the highest height approximately equal to the height of the gear cover portion is not overlapped with the cam cover portion on the front side of the vehicle body when viewed perpendicularly to the mating surface of the head cover with the cylinder head. And one end of the air guide wing is connected to the side surface of the gear cover, and the other end of the air guide wing is extended in the vehicle front-rear direction to form a pair of front and rear cam covers. When the wind guide wings are integrated with the head cover, the shape of the head cover can be simplified while maintaining the cooling performance of the cylinder head, eliminating the need for sliding when molding the head cover by casting. Manufacturing is facilitated.

By the way, the height of the air guide vanes is limited for simplification of the shape of the head cover, but in the present invention, the maximum height of the air guide vanes is substantially the same as the gear cover which is originally higher than the cam cover. In the engine mounted on the vehicle body with the cylinder axis inclined forward, make sure that the cam cover on the front side of the vehicle body does not overlap in the vertical direction with respect to the mating surface of the engine head cover with the cylinder head. On the other hand, since the wind guide vanes are arranged at a position deviated to the rear of the vehicle body, the wind guide vanes are located at a position sufficiently higher than the cam cover section on the front side of the vehicle body, and high cooling is achieved by the wind guide effect. Performance is ensured.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

1 is a side view of an engine provided with a cylinder head cooling device according to the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, FIG. 3 is a sectional view taken along line III-III of FIG. 4 is a plan view of the head cover, FIG. 5 is a side view of the head cover (a view in the direction of arrow A in FIG. 4), and FIG. 6 is a view B in arrow direction of FIG.
7 is a view in the direction of arrow C in FIG. 4, FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 4, and FIG. 9 is a side view of the motorcycle.

First, the schematic structure of the motorcycle 1 shown in FIG. 9 will be described. In the figure, reference numeral 2 denotes a front fork, 3 denotes a main frame, 4 denotes a down tube, and a front wheel 5 is rotatable at the lower end of the front fork 2. It is pivoted on.

An air-cooled four-cycle four-cylinder engine 6 having a cylinder head cooling device according to the present invention is disposed in a space surrounded by the main frame 3 and the down tube 4, and the engine has a cylinder axis inclined forward. It is mounted on the body. A fuel tank 7 is arranged above the engine 6, and a seat 8 is arranged behind the fuel tank 7.

On the other hand, a front end of a rear arm 10 is pivotally attached to a rear arm bracket 9 connected to a rear end of the main frame 3, and a rear wheel 11 is rotatably supported on the rear end of the rear arm 10. Have been.

Incidentally, in the engine 6, as shown in FIG. 1, a cylinder body 13, a cylinder head 14, and a head cover 15 are sequentially connected to an upper portion of a crankcase 12.
As shown in FIG. 3, four cylinders 16 are arranged side by side in the cylinder body 13 in a direction perpendicular to the plane of FIG. 3, and a piston 17 is slidably fitted in each cylinder 16. ing. Each piston 17 is connected to a crankshaft (not shown) via a connecting rod 18.

The cylinder head 14 has an intake passage 20 for each cylinder.
And an exhaust passage 21 are formed. The intake passage 20 and the exhaust passage 21 are opened and closed at appropriate timing by an intake valve 22 and an exhaust valve 23, respectively.

Here, the drive system of the intake valve 22 and the exhaust valves 22 and 23 will be described. As shown in FIG.
A pair of camshafts 24 and 25 long in the vehicle width direction (perpendicular to the plane of FIG. 3) are parallel to each other in the front-rear direction of the vehicle body.
And are spaced apart. For example, a drive gear 26 is connected to an intermediate portion of one (exhaust side) camshaft 25 as shown in FIG. 2, and two cams 27, 27 are provided on both sides of the drive gear 26, respectively. Are provided integrally.

Thus, the rotational power of the crankshaft (not shown) is
When the camshaft 25 is transmitted to the camshaft 25 via the
27 open and close the exhaust valves 23 contacting these at appropriate timing. The other (intake side) camshaft 24 is configured similarly to the camshaft 25. When the camshaft 24 is driven to rotate, the intake valves 22 are opened and closed at appropriate timings.

By the way, the camshafts 24 and 25 and the drive gear 26
(Including a drive gear (not shown) connected to an intermediate portion of the camshaft 24) is covered with the head cover 15, and details of the structure of the head cover 15 will be described below with reference to FIGS. 4 to 8. explain.

That is, the camshaft is provided on the upper surface of the head cover 15.
The width direction of the vehicle body covering each of 25 and 24 (vertical direction in FIG. 4)
A pair of cam covers 15a and 15b which are longer than each other are parallel to each other in the front-rear direction of the vehicle body (the left-right direction in FIG. 4), and are swelled integrally with each other. Covers a drive chain (not shown) coupled to the shaft 24) and a drive chain (not shown) (see FIG. 2).
The gear cover 15c protrudes long in the front-rear direction of the vehicle body so as to connect the intermediate portions of the cam covers 15a and 15b. The cam covers 15a and 15b and the gear cover 15c are substantially It is shaped like a letter. Here, as shown in FIG. 5, the height of the gear cover portion 15c (the height of the head cover 15 from the mating surface with the cylinder head 14) is determined by the cam cover portion.
It is set higher than the height of 15a, 15b.

Thus, the cam cover 15a,
Spaces S, S surrounded by the gear cover 15c are formed on the left and right sides of the gear cover 15c, and are located above the spaces S, S, and the cylinder head 14 of the head cover 15.
Cam cover part on the front side of the vehicle body when viewed perpendicularly to the mating surface with
A pair of left and right wind guide wings 15d, 15d for introducing the running wind into the spaces S, S are arranged long in the vehicle width direction at positions deviated to the rear of the vehicle body so as not to overlap with 15a. Have been. Each of the wind guide vanes 15d has an inner end in the width direction connected to a side surface of the gear cover portion 15c, and an outer end in the width direction extends in the vehicle front-rear direction and is connected to a pair of front and rear cam cover portions 15a, 15b. In addition, the air guide wing part 15d,
15d is formed at the middle in the front-rear direction of the pair of front and rear cam cover parts 15a, 15b.

The air guide wings 15d, 15d have an airfoil cross section, and the maximum height thereof is set substantially equal to the height of the gear cover 15c. These air guide wing portions 15d, 15d are formed integrally with the head cover 15, and are arranged above the respective space portions S such that the lower surface thereof is located lower as the downstream side in the traveling wind flow direction. . In the front half of the upper surface of the head cover 15, air guide paths 28, 28 are formed between the air guide wing sections 15d, 15d and the cam cover section 15a (see FIG. 8).
28 is open diagonally upward toward the front of the vehicle body.

Thus, while the motorcycle 1 shown in FIG. 9 is traveling, the traveling wind flowing into the air guide passages 28, 28 opening forward on the upper surface of the head cover 15 is shown in FIG. 1 and FIG. As shown by the arrows, the air is guided by the air guide vanes 15d, 15d, and is introduced into the spaces S, S along the air guide passages 28, 28. In the present embodiment, as described above, the air guide The portions 15d, 15d are arranged such that their lower surfaces face downward along the flow direction of the traveling wind, so that the traveling wind is efficiently introduced into the spaces S, S. After the traveling wind introduced into the spaces S, S cools the cylinder head 14, the traveling wind is guided to the side of the cylinder head 14 by the negative pressure due to the traveling wind generated on the side of the cylinder head 14 and outwards. Flow away. In this way, the traveling wind is guided by the wind guide vanes 15d, 15d and is efficiently introduced into the spaces S, S to be used for cooling the cylinder head 14, so that the cylinder head 14 is efficiently cooled. The temperature rise is kept low.

And since each air guide wing part 15d of the cylinder head 15 has an airfoil cross section, the traveling wind flowing immediately above the air guide wing part 15d
d, it can be curved downward after passing through, and a cam cover portion 15b on the rear side of the vehicle body located behind the wind guide blade portion 15d.
The cam wind can be guided by the traveling wind to cool the cam cover 15b by the traveling wind.

In the present embodiment, the portion near the gear cover portion 15c of each of the spaces S formed above the head cover 15 is not far from the side portion of the engine 6, and therefore is close to the gear cover portion 15c of the space S. Negative pressure due to the traveling wind generated on the side of the cylinder head 14 acts on the front part a (see FIG. 4), so that hot air is sucked out and the entire cylinder head 14 is cooled substantially uniformly.

In the present embodiment, the air guide wings 15d, 15d
Since it is formed integrally with 5, the appearance of the engine 6 is not impaired by the wind guide wings 15d.

Further, a pair of left and right air guide wing portions 15d, 15d having a maximum height approximately equal to the height of the gear cover portion 15c is attached to the head cover 15.
In the vertical direction with respect to the mating surface with the cylinder head 14, the cam cover portion 15a on the front side of the vehicle body is disposed so as not to overlap with the cam cover portion 15a on the front side of the vehicle body so as to be displaced rearward of the vehicle body, and each wind guide wing portion 15d The widthwise inner end of the gear cover portion 15c is connected to the side surface of the gear cover portion 15c, and the widthwise outer end of each of the wind guide blade portions 15d is extended in the vehicle front-rear direction and connected to the pair of front and rear cam cover portions 15a, 15b. In the case where 15d and 15d are integrated with the head cover 15, the shape of the head cover 15 can be simplified while maintaining the cooling performance of the cylinder head 14, and the slide when forming the head cover 15 by casting or the like is unnecessary. Manufacturing is facilitated.

By the way, the height of the air guide vanes 15d, 15d is restricted for simplification of the shape of the head cover 15, but in this embodiment, the engine 6 is mounted on the vehicle body with the cylinder axis inclined forward, and the engine 6 6 head cover 15 cylinder head
The wind guide wings 15d and 15d are arranged at positions deviated rearward of the vehicle body so as not to overlap with the cam cover portion 15a on the front side of the vehicle body when viewed from the vertical direction with respect to the mating surface with 14 so that the wind guide The wing portions 15d, 15d are located at a position sufficiently higher than the cam cover portion 15a on the front side of the vehicle body, and a high cooling performance is ensured in the cooling device by the wind guiding effect.

(Effects of the Invention) As is apparent from the above description, according to the present invention, a cylinder cover is mounted on a vehicle body in a posture in which the cylinder axis is inclined forward, and is attached to a head cover attached to an upper part of a cylinder head in the vehicle longitudinal direction. A pair of cam cover portions that are parallel and spaced apart in the vehicle width direction, and extend in the vehicle front-rear direction so as to connect the pair of cam covers, and a height of the head cover from a mating surface with the cylinder head. In the cylinder head cooling device for a motorcycle engine integrally formed with a gear cover portion that is higher than the height of the cam cover portion, a space formed between the pair of front and rear cam cover portions of the head cover and on the side of the gear cover portion. And does not overlap with the cam cover portion on the front side of the vehicle body when viewed in a direction perpendicular to the mating surface of the head cover with the cylinder head. In the position deviated to the rear of the vehicle,
The air guide vane section having an airfoil cross section into which the traveling wind is to be introduced and having the highest height substantially equal to the height of the gear cover section is arranged such that the lower surface thereof is positioned lower toward the downstream side in the traveling wind flow direction. And one end of the air guide wing is connected to the side surface of the gear cover, and the other end of the air guide wing is extended in the vehicle front-rear direction and connected to a pair of front and rear cam cover parts. As a result, it is possible to efficiently cool the cylinder head and to obtain an effect that the appearance of the engine is not impaired.

[Brief description of the drawings]

1 is a side view of an engine provided with a cylinder head cooling device according to the present invention, FIG. 2 is a cross-sectional view taken along the line II-II of FIG.
3 is a sectional view taken along the line III-III of FIG. 2, FIG. 4 is a plan view of the head cover, and FIG.
FIG. 6 is a view in the direction of arrow B in FIG. 4, FIG. 7 is a view in the direction of arrow C in FIG. 4, and FIG. FIG. 9 is a side view of the motorcycle. 1 ... motorcycle, 6 ... engine, 14 ... cylinder head, 15 ... head cover, 15a, 15b ... cam cover section, 15c ... gear cover section, 15d ... wind guide wing section, S ... space section.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02F 1/34 F02F 1/32 F01P 1/02 F01P 1/10 F02F 7/00

Claims (1)

(57) [Claims] 1. A pair of cylinder covers mounted on a vehicle body with a cylinder axis inclined forward and attached to a head cover attached to an upper portion of a cylinder head, the pairs being parallel to each other in the vehicle longitudinal direction and spaced apart from each other and long in the vehicle width direction. And a gear cover portion extending in the vehicle longitudinal direction so as to connect the pair of cam covers, and a height of a head cover from a mating surface with the cylinder head being higher than a height of the cam cover portion. A motorcycle engine cylinder head cooling device comprising: a space formed between a pair of front and rear cam covers of the head cover on the side of the gear cover, and a mating surface of the head cover with the cylinder head. In a position deviated rearward from the vehicle body so as not to overlap with the cam cover part on the front side of the vehicle body in a vertical direction, The air guide vane section having an airfoil cross-section to introduce a line wind and having a maximum height substantially equal to the height of the gear cover section is arranged such that the lower surface thereof is positioned lower toward the downstream in the flow direction of the traveling wind. And one end of the air guide wing is connected to the side surface of the gear cover, and the other end of the air guide wing is extended in the vehicle front-rear direction and connected to a pair of front and rear cam cover parts. A cylinder head cooling device for a motorcycle engine, comprising: