JPH1182017A - Cooling system for water-cooled engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify structures of a water jacket and a water pump in a water- cooled engine. SOLUTION: A pump attaching recession 41 and a water jacket 45 are formed on a pair of opposed lateral side surfaces of a substantially rectangular parallelopiped shape main body 1, through pattern drawing by die-casting molding. The water jacket 45 on the right surface is covered with an inlet cover 2. The pump attaching recession 41 on the left side surface serves as a part of the water jacket, to which a pump body 43 of a water pump 40 is fitted for covering the recession with a lid. An impeller 46 is faced to the water jacket 45 through a water passage 43a formed on a center portion of the pump body 43. A driving part of the water pump 40 is projected into a chain chamber 32, driven by a cam chain 35, and fixed by a cam chain cover 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-cooled engine provided with a cylinder having a water jacket without using a core.

[0002]

2. Description of the Related Art In a general water-cooled engine, a cylinder block, a cylinder head, and a cylinder head cover are separately formed by casting, and are assembled in an overlapping manner. In this case, the cylinder head is cast by gravity casting, and the water jacket is generally formed by a core. Die casting is also used for forming the cylinder block, and in this case, the water jacket is usually formed by die cutting in the cylinder axial direction.

[0003] In the case of manufacturing a cylinder and a cylinder head for the above-mentioned general water-cooled engine by casting, a core is used for forming a water jacket. In addition, this core is disposable and wasteful. When the water jacket is formed by die-cutting in the cylinder axis direction by die-casting, consideration must be given to cooling efficiency because the mold for the water jacket must be thin and long. In addition, since the thin and long water jacket portion is liable to cause a hot water flow, the accuracy of the product is hardly obtained.

In order to solve such a problem relating to the mold structure of the long and thin oil jacket forming portion in die casting, Japanese Utility Model Publication No. Hei 5-17377 discloses that the entirety of the cylinder is open to the side and is separated from the outside. An engine with an oil jacket closed by attaching a body cover is shown.

Further, with regard to the arrangement of the water pump, Japanese Patent Laid-Open No. Hei 4-269324 discloses that a water pump is mounted on a side of a cylinder facing a chain chamber covered with a cam chain cover.
The structure in which the sprocket of the water pump is arranged on the same plane as the rotating surface of the cam chain is shown. 62-14
No. 1621 shows a structure in which a water pump is fitted into a mounting portion provided on the cylinder side facing the chain chamber, and the periphery of the water pump is bolted to the side surface of the cylinder. In Japanese Utility Model Laid-Open No. 2-35926, a water pump is externally mounted at a position on a side of a cylinder head of a chain chamber, and a sprocket provided on the pump shaft is driven by a cam chain, and an end of the pump shaft toward the engine is provided. The structure in which the portion is supported on the side surface of the cylinder head is shown.

[0006]

Problems to be Solved by the Invention
Even if an oil jacket opened to the side of the cylinder is formed as in No. 77, the water (oil) jacket must be covered with a separate cover, and a separate water pump must be provided. Must. Moreover, if the water jacket is formed on the entire periphery of the cylinder in this way, the mold structure becomes more complicated and the post-processing increases.

In addition, when a water pump driven by a cam chain is mounted, in each of the above-mentioned known examples, a pipe must be provided between the water pump and the water jacket with a hose or the like, which also complicates the piping structure. . Therefore,
There is a demand for a cooling device which can simplify the structure by increasing the number of components and reduce the number of parts and the number of assembling steps, and which can be advantageously formed and can simplify the piping structure.

[0008]

According to a first aspect of the present invention, there is provided a cooling device for a water-cooled engine according to the present invention, which includes a cylinder for slidably housing a piston of the engine, and a water surrounding the cylinder. Jacket and
In a cooling device for a water-cooled engine equipped with a water pump for forcibly circulating cooling water into the water jacket, the water jacket opens on a side surface of a cylinder, and an impeller of the water pump faces the opening. In addition, the opening of the water jacket is covered with the pump body of the water pump.

[0009] The second invention is the above-mentioned first invention, wherein:
A support portion for a pump shaft to which the impeller is mounted is provided on a cylinder outer peripheral wall surface in the opening.

In a third aspect, in the first aspect,
The water jacket is characterized by being formed by a pair of dies opposed to each other with the cylinder interposed therebetween in a direction perpendicular to the cylinder axis.

[0011] In a fourth aspect based on the third aspect,
The pull-out direction of the pair of dies coincides with the axial direction of the camshaft of the engine.

According to a fifth aspect, in the first aspect,
A water passage is formed in the pump body to directly open and communicate with the water jacket.

[0013] In a sixth aspect based on the fifth aspect,
A guide for the water passage is provided on a cover of the water jacket which covers a portion of the water jacket different from the place where the water pump is provided.

In a seventh aspect based on the first aspect, the water jacket is formed by left and right die-cutting, and a part of the water jacket is provided in a chain chamber for accommodating a cam chain disposed on the side of the cylinder. A water pump is provided between the cam chain and the cylinder, and the water pump is accommodated in the opening and the impeller faces the water jacket.

According to an eighth aspect based on the seventh aspect,
The pump body of the water pump is provided with a guide portion to the water passage.

[0016]

According to the first aspect of the present invention, the water jacket is opened to the side of the cylinder, the impeller of the water pump faces the opening, and the opening of the water jacket is covered with the pump body of the water pump. Therefore, the water pump can be used as a cover for the water jacket. Therefore, the structure can be simplified by increasing the number of functions of the parts, the number of parts and the number of assembly steps can be reduced, and the size can be reduced. In addition, there is no need to pipe between the water pump and the water jacket with a hose or the like.

According to the second aspect of the present invention, since the pump shaft support to which the impeller is mounted is provided on the outer peripheral wall surface of the cylinder in the opening, the pump shaft can be supported in the water jacket, and the impeller can be supported by the water jacket. It becomes easy to arrange it so that it faces.

According to the third aspect of the present invention, the water jacket is formed by the pair of dies which are arranged opposite to each other with the cylinder interposed therebetween in a direction orthogonal to the cylinder axis. It can be formed, and the core for forming the water jacket, which was necessary when manufacturing by the conventional casting method, can be eliminated, so the number of processes and the number of personnel can be reduced, and in addition, the water jacket part when using die casting In addition, it is not necessary to consider the cooling efficiency of the mold, the accuracy of the water jacket can be improved, and the degree of freedom of the shape can be improved.

According to the fourth aspect, the direction in which the pair of dies is pulled out coincides with the axial direction of the camshaft of the engine.
The split structure of the mold is simplified, and the cam chamber can be formed simultaneously with the formation of the water jacket.

According to the fifth aspect of the present invention, since the water passage is formed in the pump body so as to directly open and communicate with the water jacket, the water passage to the water pump can be easily formed.

According to the sixth aspect of the present invention, the water jacket is provided with a guide to the water passage in a cover of the water jacket which covers a portion different from the place where the water pump is provided. Utilizing this, the cooling water in the water jacket can be smoothly guided to the water passage of the water pump.

According to the seventh aspect, a part of the water jacket formed by the left and right die-cuttings is opened facing the chain chamber accommodating the cam chain disposed on the side of the cylinder, and the opening is formed. Since the water pump accommodated in the water pump is disposed between the cam chain cover and the cylinder, the pump body of the water pump can have a function as a lid of a water jacket formed by stamping.

According to the eighth aspect of the present invention, since the guide part for the water passage is provided in the pump body of the water pump, the cooling water in the water jacket can be smoothly fed to the water passage of the water pump using the guide part. I can guide you to .

[0024]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment applied to a water-cooled four-cycle small displacement engine for wheels will be described. 1 is an overall sectional view of the engine according to the present embodiment, FIG. 2 is a view showing a right side of the main body with an inlet cover removed, FIG. 3 is a view showing a left side of the main body with a cam chain cover removed, and FIG. 4-4 section view of
5 is a cross-sectional view taken along line 5-5 in FIG. 1, FIG. 6 is a cross-sectional view of the main body, FIG. 7 is a diagram showing a joint surface side of an inlet cover, FIG. Is a sectional view showing a casting mold of the main body, and FIG. 10 is a sectional view of the mold showing a method of forming a water jacket portion.

First, a schematic structure of the engine will be described with reference to FIGS. This engine has a substantially rectangular parallelepiped main body 1 formed of a suitable metal such as an aluminum alloy by a casting method such as die casting, and has an inlet cover 2 and two parallel side surfaces formed in the longitudinal direction thereof. It is assembled by attaching the cam chain cover 3, and is attached to a crankcase (not shown).

The main body 1 includes a cylinder section 5 for accommodating a piston 4 connected to a crankshaft (not shown) via a connecting rod 4a, a head section 8 having a cam chamber 7 for accommodating a camshaft 6 rotatably. Are integrally formed by casting.

In the present application, the cam chamber 7 of the head 8
In particular, for convenience, the surface on which the inlet cover 2 is mounted is the right side surface 10 and the surface on which the cam chain cover 3 is mounted is the left side surface 11 (FIG. 6). The surface on which a radiator described later is attached is referred to as a front surface 12 and the other surface is referred to as a back surface 13 (FIG. 5). The outer surface of the ceiling of the head cover 9 is referred to as a top surface 14, and the surface attached to the crankcase is referred to as a bottom surface 15 (FIG. 1).

A cylinder 16 has a bottom surface 15
The combustion chamber 17 formed from the side to the substantially middle part in the longitudinal direction of the main body 1 and formed on the head part 8 side, which is the innermost part of the cylinder 16, communicates with the intake port 18 and the exhaust port 19. The opening on the combustion chamber 17 side is an intake valve 20.
And the exhaust valve 21 to open and close each valve axis C1, C2
Is a predetermined valve included angle with respect to the cylinder axis C. Reference numerals 20a and 21a are stem holders.

The intake port 18 communicates with an intake passage 22 formed in the inlet cover 2. The intake passage 22 extends obliquely outward on an extension of the intake port 18, and extends through an inlet pipe 23 through a carburetor (not shown). (Omitted). The exhaust port 21 bends and extends in a direction substantially perpendicular to the intake port 18, and is connected to an exhaust pipe 24 on the back surface 13. Reference numeral 29 in FIGS. 2 and 3 denotes a spark plug.

Each valve is driven by cams 27, 2 via valve lifters 25, 26 provided at the respective shaft ends.
The camshaft 6 on which the cams 27 and 28 are formed is formed in a tapered shape by penetrating between the right side surface 10 and the left side surface 11. Both open ends of the chamber 7 are supported by bearings 30 and 31. The sliding surfaces of the cams 27 and 28 are inclined surfaces corresponding to the sliding surfaces of the valve lifters 25 and 26, respectively. A refueling portion 6a is formed between one end of the camshaft 6 and the inlet cover 2.

The other end of the camshaft 6 protrudes into a chain chamber 32 formed between the cam chain cover 3 and the left side surface 11, and a cam sprocket 33 is attached to the protruding end by a bolt 34. I have. This cam sprocket 33
Is wound around a drive sprocket provided on a crankshaft (not shown) via a cam chain 35.

Each valve axis C1 of the head cover 9
And C2, cam viewing holes 36, 37 which are coaxial with the respective valve axes C1 and C2 and have substantially the same diameter as the respective valve lifters 25, 26 are formed.
The caps 38 and 39 for opening and closing are sealed with screws via a seal.

A water pump 4 is provided near the combustion chamber 17 of the main body 1.
0 is housed in a circular pump mounting recessed portion 41 formed on a side wall portion of the main body 1 facing the cam chain cover 3, and the outer periphery of a flange 42 formed on a part of a resin cover forming the outer shape of the water pump 40 is formed. The space between the pump mounting recesses 41 is sealed by fitting in a liquid-tight manner via the O-ring 44.

The pump body 43 covers a water jacket 45 which is partially open in the pump mounting recess 41, and an impeller 46 is provided at the center of the pump body 43 and is supported so as to be able to rotate integrally with the pump shaft 47. In addition, cooling water is taken in from a water passage 43a which is directly opened to the water jacket 45 at the center of the pump body 43.

One end of the pump shaft 47 is rotatably supported by a boss 48 formed on the outer peripheral wall of the cylinder 16. The other end of the pump shaft 47 projects into the chain chamber 32 beyond the cam chain 35, a magnet ring 49 is provided therearound, and a flange 42 is further provided therearound.
A small diameter portion 50 is formed by being covered with a part of a resin cover integrated with the above. The projecting end of the small diameter portion 50 is fitted and supported in a circular fitting concave portion 51 formed in the cam chain cover 3.

As is apparent from FIG. 3, the center of the small-diameter portion 50 and the center of the flange 42 are different from each other.
Each center of the fitting concave portion 51 concentric with the pump mounting concave portion 41 concentric with the flange 42 is also different. With the small diameter portion 50 fitted into the fitting recess 51, the flange 42 is fitted into the pump mounting recess 41, and the cam chain cover 3 is
Water pump 40
Are fixed to the pump mounting recess 41.

As is apparent from FIG. 5, a sprocket 53 for a water pump in which a magnet ring 52 is integrated on the inner peripheral side is provided on the outer peripheral portion of the small diameter portion 50.
5 is driven. The outer periphery of the boss of the water pump sprocket 53 is rotatably housed in a circular water pump housing part 55 formed on the cam chain cover 3 via a bearing 54.

When the magnet ring 52 rotates integrally with the water pump sprocket 53, the magnet ring 49 in the small diameter portion 50 is magnetically coupled and rotates integrally.
, The impeller 46 is rotated, and the water pump 40 is driven.

On the front surface 12 of the main body 1, a water outlet 56 and a water inlet 57 are formed to protrude side by side, respectively. The water outlet 56 is formed near the cam chain cover 3 and communicates with a discharge passage 58 provided in the pump body 43. The discharge path 58 is provided with the impeller 4 inside the pump body 43.
6 is continuous with a substantially arc-shaped passage portion 59 leading to the periphery. The water inlet 57 is located near the inlet cover 2 and communicates with the water jacket 45.

A return port 61 and a water supply port 62 of a radiator 60 are directly fitted and connected to the water outlet 56 and the water inlet 57, respectively. The return port 61 extends straight through the radiator 60 in the direction in which the discharge path 58 extends. It is connected to an upper tank 64 via a return passage 63 extending like a circle.

As shown in FIG. 6, the head portion 8 of the main body 1 is provided with valve lifter holes 84, 85 for accommodating the valve lifters 25, 26,
8 and small-diameter stem holder hole 8 extending to exhaust port 19
6, 87 are formed and each of these holes is along the valve axis C1 or C2, and the extension of each valve axis C1 or C2 extends intersecting with the axis of the camshaft 6 (the center axis of the cam chamber). A cam viewing hole 36 is provided in the head cover 9 on the extension,
37 are formed.

As shown in FIG. 7, the right side 10
A rectangular cooling water seal 65, an elliptical intake seal 66, and a substantially P
A letter-shaped oil portion seal 67 is formed, and the inlet cover 2 is put on the right side surface 10 of the main body 1 so that
Water, an air-fuel mixture, and oil are separated and sealed between the right side surface 10 and the inlet cover 2.

Reference numeral 67 in FIG. 7 denotes a recess communicating with an oil passage 67a (FIG. 5) leading to a main gallery (not shown), and 68 denotes an oil supply portion 6a (FIG. 1) formed at the shaft end of the cam shaft 6. 4), a reference numeral 69 in FIG. 4 denotes a boss for mounting the spark plug 29.

FIG. 9 shows a mold structure for molding the main body 1 shown in FIG. 1. The right die 70 forming the right side surface 10 of the main body 1, the left die 71 forming the left side surface 11, and the cylinder 16 are shown. And a top mold 73 forming the top surface 14 side. In addition, as shown in FIG.
The front mold 92 and the back mold 97 are also used for forming the front 12 and the back 13 respectively.

The right mold 70 includes a projection 74 corresponding to one end bearing portion of the camshaft, a projection 75 forming a pilot hole 18a corresponding to a part of the intake port 18, and a water jacket 45 on the inlet cover 2 side. Corresponding projections 76 and the like are formed.

The left mold 71 has a tapered tapered projection 77 for forming the cam chamber 7 by casting, a pin 79 for forming a breather hole 78, and a projection 80 corresponding to the pump mounting recess 41.
Is formed, and at the center of the protrusion 80, a formed portion 81 corresponding to the boss portion 48 is formed.

The cylinder mold 72 has a projection 82 corresponding to a pilot hole 18 b forming a part of the intake passage 18 and an exhaust port 1.
A protrusion 83 corresponding to the pilot hole 19a corresponding to the portion 9 is formed. The upper die 73 is provided with projections 97 and 98 for simultaneously forming the cam viewing holes 36 and 37 by casting.

After these molds are closed and die-casting is performed, when each mold is opened, the main body 1 is taken out in a state where each surface and various concave portions and spaces are formed. In particular, the left side surface 11 of the main body 1 is formed by the left mold 71 which is opened to the left, and at the same time, the cam chamber 7 is cast out by the protrusion 77 which is pulled out in the same direction in parallel with the axis of the camshaft 6, and will be described later. Also, the pump mounting recess 41 and the left side portion of the water jacket 45 are simultaneously formed by casting.

Thereafter, each pilot hole (18a, 18, 19a)
Drilling and shaping of the inner peripheral surface of the hole, lifter hole 84, etc.
A small amount of mechanical processing, such as drilling of the holes 85 and the valve stem holder holes 86 and 87 and threading of the peep holes 36 and 37, can reduce the head cover 9 to cover the cylinder 5, the head 8 and the cam chamber 7 above. The body 1 in which the persons are integrated is completed.

FIG. 10 shows a mold structure for molding the water jacket 45, in which the protrusion 76 of the right mold 70 and the left mold 7 are formed.
Each of the protrusions 80 includes semicircular arc-shaped molding surfaces 90 and 91 so as to surround the periphery of the cylinder mold 72 in a ring shape with a gap about the thickness of the cylinder 16.
Are provided with cast pins 93 and 94 for casting the water outlet 56 and the water inlet 57, and a projection 96 forming an intermediate concave portion 95. Reference numeral 97 denotes a back type.

As shown in FIG. 5, each molding surface 90, 91
Guide portions 10 are provided at four corners of cylinder portion 5 surrounding cylinder 16.
1, 102, 103, and 104 are formed in the fitting space. These guides 101, 102, 103 and 1
Numeral 04 denotes a curved curved guide surface which is substantially parallel to the outer periphery of the cylinder 16. The guide portions 101 and 102 are formed to protrude from the pump body 43, and the guide portions 103 and 104 are formed on the water jacket 45 side of the inlet cover 2.

The water jacket 4 of the pump body 43
A water passage 43a is formed between the guide portions 101 and 102 on the surface facing the surface 5. Also, the guides 103 and 104
The surface facing the water jacket 45 of the inlet cover 2 as a whole forms one guide surface 105. However, a portion of the guide surface 105 near the water inlet 57 is partially formed with a relief surface 106 for forming an enlarged space for facilitating the flow of cooling water from the radiator 60 to the water jacket 45. Air cooling fins 107 are integrally formed on the outer surface side of the inlet cover 2.

Next, the operation of this embodiment will be described. The water jacket 45 is opened to the pump mounting recess 41 on the side of the cylinder portion 5 and the water pump 4 is inserted into the pump mounting recess 41.
0, and the water jacket 4
5, the pump body 43 of the water pump 40 is covered.
Can be provided with a function as a cover for covering the water jacket 45, so that the structure can be simplified by increasing the number of components, the number of components and the number of assembly steps can be reduced, and the size can be reduced.

The flange 42 of the water pump 40 is formed in a circular shape, and the outer periphery of the flange 42 is
Since the seal is formed by the ring 44 and fitted in a liquid-tight manner, the sealing structure between the water pump 40 and the pump mounting recess 41 is simplified.

Furthermore, since the pump mounting recess 41 faces the chain chamber 32 and the water pump 40 is disposed between the cam chain cover 3 and the cylinder 16, the water jacket 4 is provided.
When the mold 5 is formed so as to open to the chain chamber 32 by die-cutting, it functions as a lid of the water jacket 45 and has a suitable arrangement for driving the water pump 40 by the cam chain 35.

In addition, by attaching the cam chain cover 3 to the left side surface 11, the water pump 40 can be fixed to the pump mounting recess 41 of the cylinder portion 5, so that the fixing structure is simplified and the water pump 40 is exclusively used for fastening the water pump 40. Bolts are not required, and surface pressure management is not required.

Moreover, the center of the small diameter portion 50 and the flange 42
Of the fitting recesses 51 which make the centers of
And the centers of the pump mounting recesses 41 are also different. When the flange 42 is fitted into the pump mounting recess 41 with the small diameter portion 50 fitted into the fitting recess 51, the water pump 40 Since the water pump 40 can be positioned and mounted, positioning when mounting the water pump 40 is simplified.

Further, the impeller 46 is connected to the water jacket 45 through a water passage 43a provided in the pump body 43.
Since the water pump 40 and the water jacket 45 are not directly connected to each other, there is no need to provide a pipe between the water pump 40 and the water jacket 45 by using a hose or the like, so that the number of parts can be reduced and the cooling water path can be made compact.

In addition, since the mounting portion 48 of the pump shaft 47 is provided on the outer peripheral wall surface of the cylinder portion 5 facing the water passage 43a, the pump shaft 47 can be supported in the water jacket 45, and the impeller 46 faces the water jacket 45. It becomes easy to make the arrangement.

Further, since the pump body 43 and the inlet cover 2 are provided with guide portions and guide surfaces 101 to 105 for the water passage 43a formed in a substantially arcuate shape and substantially parallel curved surfaces on the outer periphery of the cylinder 16, The cooling water in the water jacket 45 is smoothly guided to the water passage 43a of the water pump 40 by using these guide portions and the guide surface, so that the cooling water can be prevented from remaining on the way. Moreover, since the air cooling fins 107 are integrally formed on the outer surface side of the inlet cover 2 facing the water jacket 47, the cooling efficiency can be improved.

Further, the water jacket 45 is directed to the side of the cylinder portion 5 by a pair of right and left dies 70 and 71 which are arranged opposite to each other across the cylinder portion 5 in a direction perpendicular to the cylinder axis C. It is formed from left and right so as to open. For this reason, the core required when the water jacket 45 is manufactured by casting in the conventional casting method can be eliminated, and many man-hours required for core creation and sand removal become unnecessary. The number can be reduced. In addition, when the die casting is adopted, it is not necessary to consider the cooling efficiency of the water jacket portion with respect to the mold, so that the accuracy of the water jacket 45 can be improved and the degree of freedom of the shape can be improved.

Further, since the water jacket 45 is formed by cutting the right mold 70 and the left mold 71 in the axial direction of the camshaft 6, the split structure of the mold is simplified, and the formation of the water jacket 45 is simplified. At the same time, the cam chamber 7 can be formed by casting.

Furthermore, the water jacket 45
Simultaneously, the main body 1 in which the three parts of the cylinder part 5, the head part 8, and the head cover part 9 covering the upper part of the cam chamber 7 are integrated can be die-cast using a mold.
Since only a small amount of machining is required as post-processing on the main body 1 after casting, the production efficiency of the main body 1 is improved. In addition, since the molding surface formed by the mold is relatively beautiful and dense, there are many places where such finishing treatment by machining is unnecessary, which is further advantageous in manufacturing.

The present invention is not limited to the above embodiments but can be variously modified. For example, the casting method does not necessarily have to be aluminum die casting.
Other known casting methods such as using a sand mold can be adopted.

[Brief description of the drawings]

FIG. 1 is an overall sectional view of an engine according to an embodiment.

FIG. 2 is a diagram showing a right side surface with an inlet cover removed.

FIG. 3 is a diagram showing the left side surface with the cam chain cover removed.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 1;

FIG. 7 is a diagram showing a joining surface side of the inlet cover.

FIG. 8 is a diagram showing a joining surface side of the cam chain cover.

FIG. 9 is a sectional view showing a casting mold of the main body.

FIG. 10 is a sectional view of a mold showing a method of forming a water jacket.

[Explanation of symbols]

1: body, 2: inlet cover, 3: cam chain cover, 5: cylinder part, 6: cam shaft, 7: cam chamber, 8:
Head part, 9: head cover part, 16: cylinder, "3
2: Chain chamber, 35: Cam chain, 40: Water pump, 41: Pump mounting recess, 42: Flange, 43: Pump body, 43a: Water passage, 45: Water jacket, 46: Impeller

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[Procedure amendment]

[Submission date] December 1, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is an overall sectional view of an engine according to an embodiment.

FIG. 2 is a diagram showing a right side surface with an inlet cover removed.

FIG. 3 is a diagram showing the left side surface with the cam chain cover removed.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 1;

FIG. 6 is a sectional view of the main body.

FIG. 7 is a diagram showing a joining surface side of the inlet cover.

FIG. 8 is a diagram showing a joining surface side of the cam chain cover.

FIG. 9 is a sectional view showing a casting mold of the main body.

FIG. 10 is a sectional view of a mold showing a method of forming a water jacket.

[Description of Signs] 1: Main body, 2: Inlet cover, 3: Cam chain cover, 5: Cylinder, 6: Cam shaft, 7: Cam chamber, 8:
Head part, 9: Head cover part, 16: Cylinder, 3
2: Chain chamber, 35: Cam chain, 40: Water pump, 41: Pump mounting recess, 42: Flange, 43: Pump body, 43a: Water passage, 45: Water jacket, 46: Impeller

Claims (8)

[Claims] 1. A cooling system for a water-cooled engine, comprising: a cylinder for slidably receiving a piston of an engine; a water jacket surrounding the cylinder; and a water pump for forcibly circulating cooling water into the water jacket. In the apparatus, the water jacket is opened to a side surface of a cylinder, and an impeller of a water pump faces the opening, and an opening of the water jacket is covered by a pump body of the water pump. Engine cooling system. 2. A cooling device for a water-cooled engine according to claim 1, wherein a support portion for a pump shaft to which said impeller is mounted is provided on a cylinder outer peripheral wall surface in said opening. . 3. The water-cooled water-cooling system according to claim 1, wherein said water jacket is formed by a pair of dies which are arranged to face each other with the cylinder interposed therebetween in a direction orthogonal to the cylinder axis. Engine cooling system. 4. The cooling device for a water-cooled engine according to claim 3, wherein the direction in which the pair of dies is removed coincides with the axial direction of the camshaft of the engine. 5. A cooling device for a water-cooled engine according to claim 1, wherein a water passage is formed in said pump body to directly open and communicate with a water jacket. 6. The water jacket according to claim 5, wherein a guide portion to the water passage is provided on a cover of the water jacket which covers a portion of the water jacket different from a place where the water pump is provided. A cooling device for a water-cooled engine according to claim 1. 7. A water jacket is formed by left and right die-cutting, and a part of the water jacket is opened facing a chain chamber accommodating a cam chain arranged on a side of the cylinder, and is opened to the opening. 2. A cooling device for a water-cooled engine according to claim 1, wherein a water pump, which is accommodated and whose impeller faces the water jacket, is arranged between the cam chain cover and the cylinder. 8. The cooling device for a water-cooled engine according to claim 7, wherein a guide portion to said water passage is provided in a pump body of the water pump.