Title of Invention

"A COOLING DEVICE FOR WATER-COOLED INTERNAL COMBUSTION ENGINE"

Abstract To reduce the number of components and assembling steps for mounting and operating a cooling water pump of a cooling device in a water-cooled internal combustion engine. [Means of Solution] A camshaft 18 for operating a valve system of the internal combustion engine is disposed at an upper part of a cylinder head 5, and is rotated by a crankshaft 9 via a transmission 23. A cooling water pump 50 is attached to a cylinder head cover 6 disposed on the cylinder head 5, and is rotated by the camshaft 18. A rotary shaft 53 of the cooling water pump 50 is coupled, via a magnet coupling, to the camshaft 18 in a chamber 62 housing the transmission mechanism 23.
Full Text [0001]
[Field of the Invention]
This invention relates to a cooling device for a
water-cooled internal combustion engine having a relatively small displacement in a small vehicle such as a motorcycle, and more particularly to a cooling device for a water-cooled internal combustion engine in which an improved structure is used in order to mount a cooling water pump. [0002]
[ Problems to be solved by the Invention]
Usually, in an overhead camshaft type internal combustion engine, a mounting area (i.e. a split area) for a cylinder head cover on a cylinder head is flush with a split area of a camshaft.
t
An extension of the camshaft coincides with the split area QJ! the cylinder head cover. Therefore, it is difficult to operate a cooling water pump using the camshaft when the cooling water pump is arranged on the extension of the camshaft.
In order to overcome the foregoing problem, the cooling water pump is usually disposed on a crankcase or a cylinder head except for the cylinder head cover. This requires a dedicated shaft in order to rotate the cooling water pump. [0004]-
There exists a cooling water pump which is disposed on an extension of a camshaft and is rotated by the camshaft (refer to Japanese Utility Model Publication No. Sho 64-7204) . In the publication, camshaft bearings which are independent from a cam casing and a casing cover are interposed between an area where the cam casing and casing cover face each other and the camshaft passes through. The cooling water pump is mainly supported by the cam casing with cylindrical pump casing bearings fitted to the camshaft bearings. [0005]
It may be possible to say that the camshaft bearings are designed as common parts. However, such a component is not always required to mount and support the cooling water pump.
Further, use of camshaft bearings necessitates members for preventing leakage of liquid at to two positions where the camshaft bearings pass through the cam casing and casing cover,

and where cylindrical pump casing bearings of the cooling water pump are fitted to the camshaft bearings. This means an increase in the number of components.
[Means to Solve the Problems and Effects]
The invention is intended to provide a cooling device for a water-cooled internal combustion engine in order to overcome the foregoing problems of the related art. There is provided a cooling device for a water-cooled internal combustion engine defined in claim 1. The cooling device is characterized in that: a camshaft for operating a valve system of the internal combustion is disposed at an upper part of a cylinder head, and is rotated by a crankshaft via a transmission mechanism; and a cooling water pump is attached to a cylinder head cover disposed on the cylinder head and is rotated by the camshaft.
Accordingly, there is provided a cooling device for a water-cooled internal combustion engine, wherein:
a camshaft for operating a valve system for internal combustion is disposed at an upper part of a cylinder head, and is rotated by a crankshaft via a transmission mechanism; and characterized in that
a cooling water pump is attached to a cylinder head cover disposed on said cylinder head and is rotated by said camshaft.

In the cooling device defined in claim 1, the coolinq water pump is rotated by the camshaft, which means that no dedicated shaft is necessary for the operation of the cooling water pump. The cooling water pump is disposed on the cylinder head cover using ordinary sealing members, fixing members such as bolts, and couplers . No other components are required, which is effective in extensively reducing the number of components for attaching and operating the cooling water pump and the number of assembling steps. [0008]
The cooling device of claim I may be configured as define 1 in claim 2. In such a case, the rotary shaft of the cooling water pump is connected to the camshaft effectively using a space in the chamber for the transmission mechanism. [0009]
The cooling device according to claim 1 or 2 may b •; configured as defined in claim 3, in which the rotary shaft of the cooling water pump is connected to the camshaft via the magnet coupling. No mechanical sealing is necessary'for the rotary shaft, which enables the rotary shaft to be highly
water-tight and shortened, and have a simple structure. This is effective in reducing the size and cost of the cooling device for the internal combustion engine. Further, the cooling water pump functions effectively as the magnetic coupling type cooling water pump. [0010]
The cooling device of claim 3 may be configured as in claim A, wherein the partition of the magnetic coupling is made of a resin material. It is possible to make the cooling device compact and light, and to reduce manufacturing cost thereof. The partition is sandwiched between the cylinder head cover and pump cover, is protected against deformation, and can maintain its original shape. [0011]
Further, the cooling device according to one of claims 1 to 4 may be configured as in claim 5. The mounting area of the cylinder head cover to the cylinder head is positioned below the camshaft, the axis of the camshaft passes through the side wall of the cylinder head, and the cooling pump mounting area on the cylinder head is present outside the side wall of thj cylinder head cover where the of camshaft passes through. Thus, the mounting area for the cooling water pump can be easily formed on the cylinder head cover.
[Brief Description of the ACCOMPANYING Drawings]
Fig. 1 is a schematic perspective view of the water-cooled internal combustion engine to which the cooling device of the invention is applied according to the first embodiment defined in "claim 1 or 5.
Fig. 2 is a right side view of the engine shown in Fig. 1.
Fig. 3 is a cross section taken along line Ill-Ill in Fig. 2.
Fig. 4 is a partly large-scale view of Fig. 3.
Fig. 5 is a front view observed in the direction V in Fig. 2.
Fig. 6 is a left side view.
Fig. 7 is a cross section of the cooling device according to the second embodiment, applied to the internal combustion engine, being similar to Fig. 4.
[0012] [Description of Embodiments]
The invention will be described with reference to a first embodiment defined in claims 1 to 5 and shown in Figs. 1 to 6.
Fig. 1 is a perspective view of a water-cooled internal combustion engine 1 to which a cooling device of the invention is applied. The water-cooled four-cycle internal combustion engine 1 having an overhead camshaft and a single cylinder i -, installed on a vehicle body between front and rear wheels of a small motorcycle (not shown). [0013]
The water-cooled internal combustion engine 1 comprises split left and right crankcases 2 and 3, a cylinder block 4,

a cylinder head 5 and a cylinder head cover 6. The cylinder block 4 is placed on the crankcases 2 and 3 with the axis of a cylinder hole 7 extending substantially horizontally toward the front edges of the crankcases 2 and 3. The cylinder head 5 and cylinder head cover 6 are stacked on top of one another in front of the cylinder block 4. The crankcases 2 and 3, cylinder block 4, cylinder head 5 and cylinder head cover 6 are coupled to one another in order to form an integral member. [0014]
As shown in Figs . 3 and 4, a mounting area 65 for attaching the cylinder head cover 6 to the cylinder head 5 (i.e. split area of the cylinder head cover 6) is at a level lower than another mounting area 66 (split area) for mounting a camshaft 18 (to be described later) . The cylinder head cover 6 is coupled to the cylinder head 5 using a plurality of bolts 67 arranged along the periphery of the mounting area 65 in order to be integral with the cylinder head 5. [0015]
The axis of the camshaft 18 passes through a side wall of the cylinder head cover 6. A hole 68 for mounting a cooling water pump 50 (described later) is formed on the side wall of the cylinder head cover 6 where the camshaft 18 passes through,, shown at the left side in Fig. 3. The cooling water pump 50 is a-ttached on the outer surface 59 of the left side wall.
*.
[0016]
Referring to Figs. 3 and 4, a piston 8 is slidably f:j.tted in the cylinder hole 7. A crankshaft 9 is rotatably supported by the left and right crankcases 2 and 3. A connecting rod 12 has its opposite ends rotatably connected to the piston 8 and the crankshaft 9 via a piston pin 10 and a crank pin 11. Reciprocation of the piston 8 enables the rotation of the crankshaft 9. [0017]
An inlet port 14 and an outlet port 15 are formed on the cylinder head 5, communicating with a combustion chamber 13 at the top of the cylinder hole 7 . An intake valve 16 and an exhaust

valve 17 are rotatably disposed in the inlet and outlet ports
14 and 15, respectively.
[0018]
The inlet port 14 is positioned on the cylinder head 5 inside the mounting area 65 where the cylinder head cover 6 is attached to the cylinder head 5. Further, the inlet port 14 communicates with an intake passage 14a on the cylinder head cover 6, at the mounting area 66 where the cylinder head cover 6 is attached to the cylinder head 5 in a liquid-tight state. As shown in Figs. 3 and 4, the inlet port 14 communicates with the intake passage 14a near the right end of the camshaft 18. [0019]
The camshaft 18 is disposed at the upper part of the cylinder head 5, and is adjacent to the tops of the intake and exhaust valves 16 and 17. The camshaft 18 is rotatably supported via bearings 19 between the cylinder head 5 and a camshaft holder 20, and has a driven sprocket 21 fitted to its left large diameter end 18a, as an integral part. An endless chain 23 (i.e. a transmission mechanism) extends between a driv; sprocket 22 integral with the crankshaft 9 and the driven sprocket 21. The camshaft 18 is rotated at a speed which is half of a rotating speed of the crankshaft 9. The intake and exhaust valves 16 and 17 are opened or closed once each time the crankshaft 9 rotates twice. [0020]
Referring to Figs. 2, 5 and 6, a radiator 30, the cooling device for cooling the internal combustion engine 1, is disposed on the cylinder block 4. The radiator 30 includes: left and right cooling water tanks 31 and 32 (in Fig. 5, the left cooling water tank 31 is shown at the right side while the right tank 32 is shown at the left side); a plurality of juxtaposed flat radiating fins 33 which extend vertically in the running direction of the vehicle; and cooling water pipes 34 laid between inner walls of the cooling water tanks 31 and 32 anJ extending across the radiating fins 33 in the width direction of the vehicle. The cooling water pipes 34 are cylindrical,

and are vertically arranged in three rows, or horizontally arranged in two or three rows. Cooling water inlet/outlet ports 35 are formed on bottoms 31a and 32a of the cooling water tankd 31 and 32. (Only the inlet/outlet port 35 on the bottom 31a of the cooling water tank 31 is shown in Fig. 6. ) A connecting sleeve 38 extends downward to and is fitted in the inlet/outlet port 35 [0021]
The radiator 30 is firmly attached to the cylinder block 4 using bolts 47 which are screwed into radiator support brackets 40 and 41 (to be described later) via flanges 36 and 37 integral with the bottoms of the cooling water tanks 31 and 32. A detachable cap 39 is attached to the top of the cooling water tank 31. [0022]
As shown in Fig. 3, the radiator support brackets 40 and 41 extend from the opposite sides of the cylinder block 4, and are provided with cooling water ways 42 and 43, respectively. The right cooling water way 43 communicates with a cylindrical cooling water jacket 44 surrounding the outer surface of the combustion chamber 13. Another cooling water jacket 45 is provided on the cylinder head 5, communicating with an open end of the cooling water jacket 44. Both of the cooling water jackets 44 and 45 are tapered inward from the contacting areas of the cylinder block 4 and the cylinder head 5.
The left cooling water way 42 has its upper open end connected to the lower end of the connecting sleeve 38, and communicates with the cooling water tank 31 via the connecting sleeve 38. [0023]
Referring to Figs. 3 and 4, a recess 18b is formed at the center of the left large diameter end 18a of the camshaft 18. A plurality of permanent magnets 24 are arranged on the inner surface of the recess 18b with an equal space maintained therebetween. [0024]

The cooling water pump 50 operated by the camshaft 18 includes a partition 51 (i.e. a pump casing), a pump cover 52, and an impeller 54 which is rotatably supported by the partition 51 and the pump cover 52 in a rotor housing 51a of the partition 51 . A cylindrical permanent magnet 55 is attached around a ste.Ti 54a of the impeller 54 via the rotor housing 51a of the partition 51. The magnet 55 has poles whose number corresponds to that of the permanent magnets 24 of the camshaft 18. The magnets 55 and 24 constitute a magnetic coupling. The impeller 54 of the cooling water pump 50 is magnetically coupled to the camshaft 18, and is rotated in response to the rotation of the camshaft 18. [0025]
The partition 51 (i.e. magnetic coupling) is made of a resin material such as PPS. A large diameter portion at the base of the rotor housing 51a is fitted in the pump mounting hole 68 formed on the left side wall of the cylinder head cover 6. In other words, the partition 51 is sandwiched between the left side wall of the cylinder head cover 6 and the pump cover 52. [0026]
An inlet section 56 of the cooling water pump 50 communicates, via a pipe 46, with the lower opening 42a of the cooling water way 42 of the left radiator support bracket 40 as shown in Fig. 6. A discharge section 57 of the cooling water pump 50 communicates with a discharge passage 58 (defined by the partition 51) of the pump cover 52. A passage 59 of*~the partition 51 communicating with the discharge passage 58 and a passage 60 communicating with the cooling water jacket 45 of the cylinder head 5 are water-tightly coupled to the opposite ends of a pipe 61. Cooling water in the left cooling water tank 31 of the radiator 30 is introduced into the cooling water pump 50 via the cooling water way 42, the pipe 46 and the inlet section
56. Cooling water pressurized by the impeller 54 is supplied
to the cooling water jackets 44 and 45 via the discharge section
57, discharge passage 58, passage 59, pipe 61 and passage 60.

[0027]
The pipe 61 is thicker at its one end exposed to the passage 60 than at the other end in contact with the end of the passage 59. Therefore, the pipe 61 is pushed to the left by a pressure of the engine cooling water flowing through the foregoing passages, so that the pipe 61 is in close contact with or fitted to the end and peripheral surface of the passage 59. This prevents the pipe 61 from being disconnected from the passage 60.
In the first embodiment, the pipe 61 is fitted into a hole 63 on the outer surface of the cylinder head 5 surrounding the transmission chamber 62 (to be described later). This arrangement effectively keeps the pipe 61 water-tight. [0028]
An idler sprocket 25 (i.e. an idle pulley) is rotatably attached around the pipe 61 in order to engage with the endless chain 23. An idler sprocket 27 is positioned nearer the crankshaft 9 compared with the idler sprocket 25 and io rotatably attached to the cylinder block 4 via a pin 26. Idler sprockets 28 and 29 are rotatably disposed near the crankshaft 9 in such a manner that they sandwich the endless chain 23 therebetween, as shown in Fig. 6. [0029]
As shown in Fig. 6, the pipe 61 is disposed in the transmission chamber 62 housing the endless chain 23, i.e. in a space defined by the endless chain 23. The idler sprocket 25 fitted around the pipe 61 is also positioned in the foregoing space, and engages with the endless chain 23 from the inside thereof. [0030]
In the first embodiment, the cooling device having the foregoing configuration operates and is advantageous as follows.
When the water-cooled internal combustion engine 1 is activated, the camshaft 18 is rotated, and the impeller 54 magnetically coupled to the camshaft 18 is also rotated.

Cooling water in the left cooling water tank 31 is introduced into the inlet section 56 of the cooling water pump 50 via th-2 inlet/outlet port 35, connecting sleeve 38, cooling water way 42 of the radiator support bracket 40, and pipe 46. Cooling water is then pressurized by the impeller 54, and is supplied to the cooling water jackets 45 and 44 via the discharge section 57 of the cooling water pump 50, discharge passage 58, passage 59, pipe 61 and passage 60. Cooling water in the water jackets 45 and 44 flows to the right cooling water tank 32 via the cooling water way 43 of the right radiator support bracket 41, returning to the left cooling water tank 31 via the cooling water pipes 34. In other words, cooling water circulates through the cooling system. [0031]
When the motorcycle (not shown) is made to run, wind blows through the radiator fins 33 from the front part to the rear part of the vehicle, thereby cooling the radiator fins 33 heated by hot cooling water flowing through the cooling water pipes 34. The cooled radiator fins 33 cool cooling water in the cooling water pipes 34. [0032]
The cooling water pump 50 is rotated by the camshaft 18, which means that no dedicated shaft is necessary for the cooling water pump 50. The cooling water pump 50 is disposed on the cylinder head cover 6 by sealing the members and couplers*. No other components are required, which is effective in extensively reducing the number of components for attachingTand operating the cooling water pump 50 and the number of assembling steps. [0033]
The coupler (magnetic coupler) for the rotary shaft 53 of the cooling water pump 50 and the camshaft 18 is disposed in the transmission chamber 62 housing the endless chain 23 via which the cooling water pump 50 and the camshaft 18 are operatively coupled to the crankshaft 9. This enables the foregoing members to be effectively arranged using an available

space. [0034]
The cooling water pump 50 is a magnet coupling type, so that no mechanical sealing is necessary for the rotary shaft 53. Therefore, the rotary shaft 53 can be maintained in a highly water-tight state, is shortened and has a simple structure. This is effective in reducing the size and cost of the cooling device for the internal combustion engine 1. Further, the cooling water pump 50 functions effectively as the magnetic coupling type cooling water pump. [0035]
The partition 51 made of the resin material contributes to reduction of weight, size and cost of the cooling device for the internal combustion engine 1. Further, the partition 51 sandwiched between the cylinder head cover 6 and the pump cover 52 is protected against deformation, and can maintain its original shape. [0036]
The mounting area 65 (split area of the cylinder head cover 6) where the cylinder head cover 6 is attached to the cylinder head 5 is at the level lower than the mounting position of the camshaft 18. The mounting area 69 for the cooling water pump 50 can be easily formed on the side wall of the cylinder head cover 6 by changing sizes of the cylinder head cover 6 and cylinder head 5 when these members are cast. [0037]
A second embodiment defined in claims 1, 2 and 5 will be described with reference to Fig. 7.
In this embodiment, an ordinary cooling water pump 70 13 used in place of the cooling water pump 50 of the magnet coupling type. [0038]
A cylindrical thick base portion of a pump casing 71 of a cooling water pump 70 is fitted in a pump mounting hole 68. The pump casing 71 is sandwiched between the left side wall of the cylinder head cover 6 and a pump cover 72. The pump casing

71 is metallic. [0039]
A rotary shaft 73 of the pump 70 is provided with a driven sprocket 21 as an integral part at a position where the rotary shaft 73 passes through the bearing 74. Further, one end of the'camshaft 18 is integrally coupled to the driven sprocket 21.
The second embodiment differs from the first embodiment in the foregoing respect, and is substantially identical to the first embodiment. Therefore, no further explanation will be given here. [0040]
The second embodiment is effective in easily manufacturing the cooling device for the engine 1 using the ordinary cooling water pump 70 which is readily available.
Further, the second embodiment is as effective as the first embodiment except for the advantage accomplished by the magnetic coupling type cooling water pump 50.
[Description of Reference Numerals]
1 ... water-cooled internal combustion engine, 2,3 ... crankcases,
4 ... cylinder block, 5 ... cylinder head, 6 ... cylinder head cover, 7 ... cylinder hole, 8 ... piston, 9 ... crankshaft, 10 ... piston pin,
11 ... crank pin, 12 ... connecting rod, 13 ... combustion chamber,
14 ... inlet port, 14a ... intake passage, 15 ... exhaust port, 16
... intake valve, 17 ... exhaust valve, 18 ... camshaft, 18a ... large
diameter portion, 18b ... recess, 19 ... bearing, 20 ... camshaft
holder, 21 ... driven sprocket, 22 ... drive sprocket, 23 ... endless
chain (transmission mechanism) , 24 ... permanent magnets, 25 ...
idler sprocket (idle pulley), 26 ... pin, 27, 28, 29 ... idler
sprockets, 30 ... radiator, 31, 32 ... cooling water tanks, 33 ...
radiating fins, 34 ... cooling water pipes, 35 ... cooling wate-
inlet/outlet port., 36, 37 ... flanges, 38 ... connecting sleeve,

39 ... cap, 40, 41 ... radiator support brackets, 42, 43 ... cooling waterways, 44, 45 ... cooling water jackets, 46... pipe, 47... bolt, 50 ... magnet coupling type cooling water pump, 51 ... partition
(pump casing) , 52 ... pump cover, 53 ... rotary shaft, 54 ... impeller, 55 ... permanent magnet, 56 ... inlet section, 57 ... discharge section, 58 ... discharge passage, 59, 60 ...passages, 61 ... pipe, 62 ... transmission chamber, 63 ... hole, 64 ... position where inlet port 14 communicates with intake passage 14a, 65 ... mounting area
(split area of cylinder head cover split area) , 66 ... mounting area (split area) , 67... bolt, 68 ... pump mounting hole, 69 ... outer surface of cylinder head cover side wall, 70 ... cooling water pump, 71 ... pump casing, 72 ... pump cover, 73 ... rotary shaft of cooling water pump, 74 ... bearing.

WE CLAIM :-
1. A cooling device for a water-cooled internal combustion engine (1),
wherein:
a camshaft (18) for operating a valve system for internal combustion is disposed at an upper part of a cylinder head (5), and is rotated by a crankshaft (10) via a transmission mechanism (23); and characterized in that
a cooling water pump (70) is attached to a cylinder head cover disposed on said cylinder head and is rotated by said camshaft.
2. The cooling device as claimed in claim 1, wherein a-rotary shaft (53) of
said cooling water pump (70) is connected to said camshaft (18) in a chamber
(62) for said transmission mechanism (23).
3. The cooling device as claimed in claim 1 or 2, wherein said rotary shaft of
said cooling water pump (70) is connected to said camshaft (18) via a magnetic
coupling (50).
4. The cooling device as claimed in claim 3, wherein a partition (51) of said
magnetic coupling is made of a resin material and is sandwiched between said
cylinder head (5) cover and a pump cover (72).
5. The cooling device as claimed in any one of claims 1 to 4, wherein:
a mounting area (65) of said cylinder head cover to said cylinder head (5) is positioned below said camshaft (18), and an axis of said camshaft passes through a side wall of said cylinder head; and
a cooling pump mounting area (66) on said cylinder head is present outside said side wall of said cylinder head cover where the axis of said camshaft passes through.
6. A cooling device for a water-cooled internal combustion engine
substantially as hereinbefore described with reference to and as illustrated in
the accompanying drawings.






Documents:

2207-del-1998-abstract.pdf

2207-del-1998-claims.pdf

2207-del-1998-correspondence-others.pdf

2207-del-1998-correspondence-po.pdf

2207-del-1998-description (complete).pdf

2207-del-1998-drawings.pdf

2207-del-1998-form-1.pdf

2207-del-1998-form-13.pdf

2207-del-1998-form-19.pdf

2207-del-1998-form-2.pdf

2207-del-1998-form-3.pdf

2207-del-1998-form-4.pdf

2207-del-1998-form-6.pdf

2207-del-1998-gpa.pdf

2207-del-1998-petition-137.pdf

2207-del-1998-petition-138.pdf

abstract.jpg


Patent Number 222600
Indian Patent Application Number 2207/DEL/1998
PG Journal Number 36/2008
Publication Date 05-Sep-2008
Grant Date 19-Aug-2008
Date of Filing 28-Jul-1998
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISHA.
Applicant Address 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN.
Inventors:
# Inventor's Name Inventor's Address
1 TERUO KIHARA C/O KABUSHIKIDAISHA HONDA GIJUTSU KENKYUSHO,OF4-1CHUO 1-CHOME, WAKO - SHI, SAITAMA,JAPAN,
2 YUICHI TAWARADA C/O KABUSHIKIDAISHA HONDA GIJUTSU KENKYUSHO,OF4-1CHUO 1-CHOME, WAKO - SHI, SAITAMA,JAPAN,
PCT International Classification Number F01P 11/12
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 HEI-9-213614 1997-08-07 Japan