CN1820130B

CN1820130B - Engine

Info

Publication number: CN1820130B
Application number: CN200480019751.2A
Authority: CN
Inventors: 井上隆司; 增田辰哉; 铃木守; 田中章太郎
Original assignee: Yamaha Motor Co Ltd
Current assignee: Yamaha Motor Co Ltd
Priority date: 2003-07-10
Filing date: 2004-07-06
Publication date: 2011-08-10
Anticipated expiration: 2024-07-06
Also published as: WO2005005804A1; JP4052660B2; CN1820131A; CN103133114B; JPWO2005005804A1; MY143333A; JPWO2005005803A1; CN1820130A; CN103133114A; WO2005005803A1

Abstract

The invention provides an engine, wherein a water pump (19) is arranged on a cylinder head (16), a pump side cooling water passage (28) formed in the water pump (19) is directly connected to a head side cooling water passage (32) formed in the cylinder head (16), and the pump-side mounting part (34) of the water pump (19) is fitted to the head side mounting part (35) of the cylinder head (16) to connect the pump side opening part (28b) of the pump side cooling water passage (28) to the head side opening part (32a) of the head side cooling water passage (32), thus piping from the water pump to the cylinder head is not required.

Description

Motor

Technical field

The present invention relates to water pump is installed on cylinder head, and the pump side cooling water path of this water pump is connected the motor on the lid side cooling water path of cylinder head.

Background technique

Be used in the motor on vehicle etc., all be that fuel is broken out in fuel chambers all the time, utilizes its energy drives piston, thereby obtain driving force to rotatablely move from bent axle.

At this moment, owing to make the fuel outburst, thereby the rising of the temperature of motor, therefore by cooling water is circulated in motor, the temperature that suppresses motor rises.

The circulation of cooling water, be with cooling waterpump with the cooling water in radiator guiding cylinder block side, make it flow into the cylinder head side then from this cylinder block, thus cooled engine (with reference to patent documentation 1, patent documentation 2).

In addition, also know with utilization and be installed in the motor that mode that the cooling waterpump on the cylinder head of motor makes cooling water flow into cylinder head constitutes.

For example, in following patent documentation 3, on exhaust cam shaft, set pump, and import refrigeration agent, discharge from the outflow road of Aspirating valves side from the inflow road of the outlet valve of cylinder head, thus cooled engine.

In addition, in following patent documentation 4, put down in writing on the side of cylinder head and set water pump, and pump shaft has been attached at formation on the end of camshaft.At this,, cooling water is circulated in cylinder head via the pipe arrangement that is attached on the cylinder head.

Patent documentation 1: the spy opens flat 05-256134 communique

Patent documentation 2: the spy opens flat 11-50844 communique

Patent documentation 3: special public clear 63-39766 communique

Patent documentation 4: No. 3080384 communique of Japan Patent

But, in above-mentioned patent documentation 1 and 2 such cooling system structures, usually, generally carry out putting into cold water from downside, take out the circulation of the water that warms then from upside, in structure in the past, be the water that will come from water pump, import the cylinder block side of downside, its cylinder head side inflow to upside in this cylinder block is cooled off, therefore pipe arrangement from the water pump of the cylinder head side that is configured in upside to the cylinder block of downside just must be arranged, the problem that exists part number and assembling to increase man-hour.

In addition, even if in the such cooling system structure of above-mentioned patent documentation 3,4, the pipe arrangement from the water pump to the cylinder head must be arranged also, exist the part number and assembling man-hour more problem points.

Summary of the invention

So, the present invention in view of above-mentioned some and be developed into, its purpose is to provide the pipe arrangement that can deduct from the water pump to the cylinder block, thereby can cut down the motor of part number.

The present invention who is used to address the above problem, be on cylinder head, to dispose water pump, with the pump side cooling water path that is formed on this water pump, be connected the motor on the lid side cooling water path that is formed on the aforementioned cylinder head, it is characterized in that aforementioned cylinder head has: the lid side assembly department that aforementioned water pump can be installed; The drive portion of the aforementioned water pump of driving device on this lid side assembly department; Be located at aforementioned cover side assembly department diverse location on, the lid side opening portion of aforementioned cover side cooling water path; Aforementioned water pump has: shell, this shell have the pump side assembly department and the aforementioned pump side cooling water path that can be installed on the aforementioned cover side assembly department; Be configured on the aforementioned pump side assembly department, can be by aforementioned pump side assembly department being installed on the aforementioned cover side assembly department and the pump shaft that is connected with aforementioned drive portion; Can be by driving aforementioned pump shaft, via the liquor charging portion of aforementioned pump side cooling water path force feed cooling water; Be located on the aforementioned shell, can be connected to pump side opening portion in the aforementioned cover side opening portion, aforementioned pump side cooling water path on the aforementioned cover side assembly department by aforementioned pump side assembly department is installed to.

An embodiment of the invention, except above-mentioned formation, it is characterized in that, aforementioned pump side assembly department and aforementioned cover side assembly department, with the side in aforementioned pump side opening portion and the aforementioned cover side opening portion, having can be along the mutual chimeric concaveconvex shape of the axle direction of aforementioned pump shaft, and the opposing party has along the attachment face of the direction vertical with respect to axle direction.

Another embodiment of the present invention except above-mentioned formation, is characterized in that, aforementioned pump side assembly department and aforementioned cover side assembly department have can chimeric mutually aforementioned concaveconvex shape.

Another embodiment of the present invention, except above-mentioned formation, it is characterized in that, on aforementioned cylinder head, be provided with intakeport, be provided with the thermostat assembly department of the discharge portion that the aforementioned cooling water that provides to aforementioned cover side cooling water path from aforementioned cover side opening portion is provided simultaneously, aforementioned thermostat assembly department be formed on same plane of the opening portion of aforementioned intakeport or parallel position on.

Another embodiment of the present invention, except above-mentioned formation, it is characterized in that, camshaft with aforementioned cylinder head is the boundary, be provided with intakeport in side's side, simultaneously be provided with relief opening, and constitute in aforementioned exhaust side and be provided with aforementioned cover side opening portion, near the aforementioned relief opening of aforementioned cover side cooling water path, provide aforementioned cooling water from this lid side opening portion in the opposing party's side.

Another embodiment of the present invention except above-mentioned formation, is characterized in that, the opening portion of aforementioned relief opening is in the mode towards the direction that deviates from aforementioned water pump, with respect to the axle direction inclination of camshaft.

According to the present invention, owing to constitute in such a way, promptly on cylinder head, have the side of lid assembly department and lid side opening portion, on the shell of water pump, have simultaneously pump side assembly department and pump side opening portion, and can cover on the side assembly department by the pump side assembly department is installed to, the pump side opening portion is connected to covers in the side opening portion, therefore can be with the lid side assembly department and the lid side opening portion of cylinder head, with the pump side assembly department and the pump side opening portion of the shell of water pump, form respectively same towards.Therefore, can be respectively from the lid side assembly department of phase the same side processing vapor cylinder cap and pump side assembly department and the pump side opening portion that covers the shell of side opening portion and water pump, the processing of the shell of cylinder head and water pump is easier to.

And, as long as owing to will cover the side assembly department and the pump side assembly department is bonded together, just drive portion and pump shaft can be linked together, lid side opening portion and pump side opening portion can be linked together simultaneously, thereby pump side cooling water path and lid side cooling water path are communicated with, therefore can deduct the pipe arrangement of the cooling water between water pump and the cylinder head, and can cut down part number and assembling man-hour, can form the outward appearance of the cooling system structure of motor simultaneously simply.

According to an embodiment of the invention, the concaveconvex shape of a side in making pump side assembly department and lid side assembly department and pump side opening portion and lid side opening portion is along axle direction when chimeric, even if the opposing party's position relation skew a little, owing to have along the attachment face of the direction vertical with respect to axle direction, therefore can absorb the skew of position relation, can at an easy rate cylinder head and water pump be bonded together.

According to another embodiment of the present invention, by making pump side assembly department and lid side assembly department chimeric, can will be configured in the pump shaft on the pump side assembly department and be configured in the contraposition and linking together accurately of the drive portion that covers in the side opening portion.

According to another embodiment of the present invention, in the man-hour that adds of cylinder head, can process intakeport and thermostat attachment face from equidirectional, the processing of cylinder head is easier to.

According to another embodiment of the present invention, can be with the water quench cylinder head exhaust valve side that just provides from water pump, and cooling cylinder lid effectively.

According to another embodiment of the present invention, by covering side opening portion than the more close exhaust side setting of camshaft, even if in the configuration of exhaust side, produce restriction, also can further shorten the distance from the outlet valve to the relief opening, and the heat transfer surface between from the outlet valve to the relief opening can be suppressed for less.

Description of drawings

Fig. 1 is the skeleton diagram of the motor of this working of an invention form.

Fig. 2 is the figure that sees cylinder head etc. with the water pump section of this example and from the top.

Fig. 3 is the front view of the state on the cylinder head that the water pump of this example is installed to.

Fig. 4 is the front view of seeing from the installation water pump side of the cylinder head of this example.

Fig. 5 is the planimetric map of the cylinder head of this example.

Fig. 6 is the worm's eye view of the cylinder head of this example.

Fig. 7 is the side view of the cylinder head of this example.

Embodiment

Below, this working of an invention form is described.

In Fig. 1 and Fig. 2, showed this working of an invention form.

At first explanation constitutes, and label 11 among Fig. 1, is the motor that is provided in as 4 circulations of the single cylinder on the motor bike of riding vehicle, 4 valves, on this motor 11, is provided with bent axle 12, via connecting rod 13 bindings piston 14 is arranged on this bent axle 12.

In cylinder block 15, to move up and down, the mode of bent axle 12 rotations is constituted via connecting rod 13 by this piston 14.

At the upside of this cylinder block 15, be fixed with cylinder head 16.On cylinder head 16, rotation is equipped with camshaft 20 freely, and this camshaft 20 and bent axle 12 are connected via cam chain 21, and by rotary crankshaft 12, camshaft 20 will rotate via cam chain 21.And be constituted as,, each

valve

22,23 air-breathing and that exhaust is used opened and closed with predetermined timing by these camshaft 20 rotations.

And, on this motor 11,, on the side of an end 20a side of the camshaft 20 of cylinder head 16, water pump 19 is installed as Fig. 2 and shown in Figure 3.

At first, on cylinder head 16,, on the side of an end 20a side of camshaft 20, be provided with the lid side assembly department 35 that water pump 19 is installed as Fig. 2 and shown in Figure 4.This lid side assembly department 35 has the chimeric recess 35a of circular port shape, surrounds the axle direction connecting groove 20b as the drive portion of water pump 19 on the end 20a be located at camshaft 20, and forms along the axle direction of camshaft 20.

In addition, be provided with in inside and cover side cooling water path 32, the lid side opening 32a of portion of a side's of lid side cooling water path 32 end is arranged on the different position with lid side assembly department 35 with the side of covering side assembly department 35 homonymies.At this,, form along the direction vertical with respect to the axle direction of camshaft 20 as the end face 32c of the attachment face that covers the side opening 32a of portion and the end face 35b on every side of chimeric recess 35a.

And then, on this cylinder head 16,, be the boundary with camshaft 20 as Fig. 5 and shown in Figure 6, be provided with intakeport 41 in the side's side that disposes Aspirating valves 22, be provided with relief opening 42 in the opposing party's side that disposes outlet valve 23.And,, be provided with the assembly department 36a of the thermostat 36 that becomes the discharge portion of covering side cooling water path 32 in the side of the opening portion 41a that is provided with intakeport 41 of cylinder head 16.This thermostat assembly department 36a, be arranged on the end face of the opening portion 41a of intakeport 41 on the position of leaving mutually with one side or parallel face.

In addition, as Fig. 2 and shown in Figure 4, cover the 32a of side opening portion disposing than camshaft 20 more close relief opening 42 sides, as shown in Figure 6, form relief opening 42 towards the direction of leaving from a side that is provided with this lid side opening 32a of portion, and the end face of the opening portion 42a of relief opening 42 tilts in the mode towards the direction of leaving from water pump 19.

On the other hand, water pump 19 as Fig. 2 and shown in Figure 3, has formed pump side cooling water path 28, possesses the pump casing 29 that is provided with the pump side assembly department 34 on the lid side assembly department 35 that can be installed to cylinder head 16 simultaneously.Pump side assembly department 34 has the fitting projection 34a that can be fitted in the chimeric recess 35a that covers side assembly department 35.

The pump side cooling water path 28 of this pump casing 29 has the introducing port 28a that gives prominence to from pump casing 29 in a side end, has in the opposing party's end to be formed on and to cover the corresponding locational pump side opening portion 28b of the 32a of side opening portion.

Pump side opening portion 28b forms in the mode relative with the lid side opening 32a of portion of cylinder head 16, and the end face 28c as attachment face around it forms along the direction vertical with respect to the axle direction of pump shaft 25.

In addition, among the path of the pump side cooling water path 28 of pump casing 29, be formed with pump chamber 27, in inside can contain impeller 26 by the state that pump shaft 25 rotates as liquor charging portion.On the end that is attached at the pump shaft 25 on this impeller 26, be equipped with the axle direction joint 25a that can be connected along the axle direction of pump shaft 25 with the axle direction connecting groove 20b of camshaft 20, this axle direction joint 25a is configured on the pump side assembly department 34.

When being installed to such water pump 19 on the cylinder head 16, at first, with the fitting projection 34a of pump side assembly department 34,, be fitted in the chimeric recess 35a of the lid side assembly department 35 on the side of an end 20a side of the camshaft 20 that is formed on cylinder head 16 along the axle direction of pump shaft 25.At this moment, by fitting projection 34a being entrenched in the chimeric recess 35a, just the axle direction joint 25a with pump shaft 25 is connected in the axle direction connecting groove 20b of camshaft 20, and pump shaft 25 and camshaft 20 are linked together to be configured in coaxial state.Meanwhile, pump side opening portion 28b directly is connected via packing ring with the state that corresponds to each other and covers on the 32a of side opening portion.

Then, by with the introducing port 28a of water pump 19 and the thermostat assembly department 36a of cylinder head 16, be interconnected on respectively on the radiator that figure do not show, constitute the circulation road of cooling water, thereby finished the installation of water pump 19 to cylinder head 16.

In the motor 11 that such water pump 19 has been installed, when making bent axle 12 rotations when driving motor 11,, be attached at the just rotation of pump shaft 25 on this camshaft 20 just via cam chain 21 rotating cam axles 20.

By the rotation of this camshaft 20, air-breathing and exhaust is used each

valve

22,23 with predetermined timing by switch, on the other hand, pump shaft 25 rotations, then the impellers 26 in the pump chamber 27 also rotate.

So by the rotation of this impeller 26, the cooling water that comes from heat sink side is inhaled in the pump chamber 27 from introducing port 28a, via pump side cooling water path 28, gone out from pump side opening portion 28b force feed from this pump chamber 27.Then, this cooling water is directly offered by the lid side opening 32a of portion from cylinder head 16 and covers side cooling water path 32, and flows in lid side cooling water path 32, thereby with cylinder head 16 coolings, and be discharged from from the assembly department 36a of thermostat 36, once more at heat sink side circulation.

Moreover, lid side cooling water path 32, as shown in Figure 1, owing to be connected on the open cylinder body side cooling water path 33 of upper-end surface side, therefore a part that flows into the cooling water that covers side cooling water path 32 flows in the cylinder body side cooling water path 33, thereby with cylinder block 15 coolings, and inflow is covered in the side cooling water path 32 once more, and the assembly department 36a from thermostat 36 is discharged from then.

At this, cylinder body side cooling water path 33 forms specific length downwards from the upper-end surface of cylinder block 15.The lower end 33a of this cylinder body side cooling water path 33 is set at height as described below, that is, in producing the scope of firing pressure, piston 14 drops to the height of the upper surface of the piston 14 that extreme lower position (is 40 °～50 ° of atdc at this) locates.Therefore, by cooling water is offered the cylinder body side cooling water path 33 of the upper side that is formed on cylinder block 15 from lid side cooling water path 32, thereby will the firing chamber around cooling.

In the motor 11 that possesses above such cooling system structure, as long as the fitting projection 34a of the pump side assembly department 34 of water pump 19 is entrenched in the chimeric recess 35a of lid side assembly department 35 of cylinder head 16, just the axle direction joint 25a of pump shaft 25 can be connected in the axle direction connecting groove 20b of camshaft 20, simultaneously, lid side opening 32a of portion and the pump side opening portion 28b that is located at and covers on side assembly department 35 and pump side assembly department 34 diverse locations can be linked together, thereby pump side cooling water path 28 directly can be connected with lid side cooling water path 32 and make its connection.Therefore, can at an easy rate water pump 19 be installed on the cylinder head 16.In addition, owing to do not need 15 the pipe arrangement from water pump 19 to cylinder block as in the past, therefore can seek the simplification in minimizing, assembling man-hour of lightweight, the water resistance of reduction, the water pump 19 of part number.And then, owing to can reduce the pipe arrangement of cooling water, therefore can make the outward appearance of cooling system structure of motor simple.

In addition,, therefore can dwindle radiator, can relatively improve cooling water temperature simultaneously, thereby can improve combustion performance (combustion efficiency) owing to can shorten

cooling water path

28,32,33 as a whole.

And then, at this,, and will flow through next water from the lid side cooling water path 32 of cylinder head 16 in the upper side formation cylinder body side cooling water path 33 of cylinder block 15, the upper side that imports this cylinder block 15 is cooled off.

By the top of such cooling cylinder lid 16 and cylinder block 15, cylinder block 15 can be cooled to required more than, therefore can improve the rate of fuel consumption rate.

That is, in the past, though be cooled to the lower side of cylinder block 15, therefore the upper side of cylinder block 15 becomes high temperature owing to be in the scope that produces firing pressure, and along with temperature downwards reduces gradually.Thereby if be cooled to the lower side of cylinder block 15 always, then viscosity uprises attached to the oil on the inwall of cylinder chamber is cooled, and slip resistance increases because of this oil.Its result, the rate of fuel consumption rate just reduces.

With respect to this, in this example, because the temperature of cylinder block 15 is higher, and only cooling produces the scope of firing pressure, so the situation that does not have oil viscosity to uprise, and slip resistance can not become greatly, can improve the rate of fuel consumption rate.

Moreover, cylinder the axle in the horizontal engine of general horizontal direction, when the inlet with cooling water is set in the front side of cylinder head, by up with heat sink arrangements, just can make cooling-water flow very natural, owing to pipe arrangement is not configured in the downside of motor, it is hereby ensured minimum height off the ground simultaneously.

In addition, in such motor 11, owing to be constituted as a side at the installation water pump 19 of cylinder head 16, has the lid side opening 32a of portion that covers side assembly department 35 and lid side cooling water path 32, and, pump side assembly department 34 covers on the side assembly department 35 by being installed to, just pump side opening portion 28b can be connected and cover on the 32a of side opening portion, therefore, the lid side assembly department 35 of cylinder head 16 and the lid side opening 32a of portion, with the pump side assembly department 34 and the pump side opening portion 28b of the pump casing 29 of water pump 19, be formed respectively identical towards.Therefore, can process each

assembly department

34,35 and each opening

portion

28b, 32a from phase the same side, the processing of the pump casing 29 of cylinder head 16 and water pump 19 is easier to.

And then, because pump side assembly department 34 and lid side assembly department 35, have along the axle direction of pump shaft 25 and camshaft 20 can be chimeric mutually fitting projection 34a and chimeric recess 35a, and pump side opening portion 28b and the lid side opening 32a of portion have along the end face 28c of the direction vertical with respect to the axle direction of pump shaft 25 and

camshaft

20,32c, therefore be that box lunch is when making pump side assembly department 34 and lid side assembly department 35 chimeric, the more or less skew of position relation of pump side opening portion 28b and the lid side opening 32a of portion also can absorb this position deflection and with

end

28c, 32c via packing ring at an easy rate liquid thickly be bonded with each other.Therefore, can more easily water pump 19 be bonded on the cylinder head 16.

In addition, because pump side assembly department 34 and lid side assembly department 35, having can chimeric mutually shape along the axle direction of pump shaft 25, therefore can be with the pump shaft 25 that is configured on the pump side assembly department 34, with be configured in an end 20a who covers the camshaft 20 in the side assembly department 35, contraposition and linking together accurately.

And, owing on an end 20a of camshaft 20, be provided with axle direction connecting groove 20b, on pump shaft 25, be provided with simultaneously axle direction joint 25a, and by they are linked together, with 25 configurations of camshaft 20 and pump shaft be attached at coaxial on, therefore can make drive portion simple in structure of water pump 19, and be easy to seek the compactness of cylinder head 16, simultaneously by with respect to camshaft 20 with pump shaft 25 be configured in accurately coaxial on, when driving, be easy to prevent the ablation of camshaft 20 and pump shaft 25 etc.

And then, become the thermostat of the discharge portion of covering side cooling water path 32 assembly department 36a owing to being provided with in intakeport 41 sides, and the opening portion 41a of thermostat assembly department 36a and intakeport 41 is formed on same plane or the parallel position, therefore can be from the end face of the opening portion 41a of the intakeport 41 of identical direction processing vapor cylinder cap 16 and the assembly department 36a of thermostat 36.Therefore, can be only on 2 directions of cylinder head 16 processing cover side assembly department 35, cover side opening portion 32, intakeport 41 and thermostat assembly department 36a.Therefore, the processing of cylinder head 16 is easier to.

In addition, owing to constitute in such a way, promptly the camshaft 20 with cylinder head 16 is the boundary, is provided with intakeport 41 in side's side, simultaneously, be provided with relief opening 42 in the opposing party's side, and then, be provided with in relief opening 42 sides and cover the 32a of side opening portion, and from this lid side opening 32a of portion cooling water is offered and to cover side cooling water path 32, therefore can compare with intakeport 41 sides and contacted relief opening 42 sides of the exhaust of high temperature with the water quench that just provides, and cooling cylinder covers 16 expeditiously from water pump 19.

And, because the opening portion 41a of relief opening 42, to tilt towards the mode of the direction of leaving from water pump 19 axle direction with respect to camshaft 20, therefore cover the 32a of side opening portion by on position, being provided with than camshaft 20 more close relief opening 42 sides, even if because the configuration of lid side opening 32a of portion and lid side cooling water path 32, restrict and in the configuration of relief opening 42 sides, produce, also can further shorten from outlet valve 23 to relief opening the distance of 42 opening portion 42a, and the heat transfer surface of relief opening can be suppressed for less.

Industrial utilizability

According to this invention, can utilize at various for motor vehicle engines such as riding vehicles, the engine of the various device usefulness such as generator etc., be equipped with on the various engines of water pump at cylinder cover.

Label declaration

11 engines, 15 cylinder blocks

16 cylinder covers, 19 water pumps

20 camshaft 20b direction of principal axis link slots

25 pump shaft 25a direction of principal axis connecting portions

26 impellers, 27 pump chambers

28 pump side cooling water path 28b pump side peristomes

29 pump cases, 32 lid side cooling water path

32a lid side opening portion 33 side cooling water path

34 pump side assembly department 34a fitting projection

The chimeric recess of 35 lid side assembly department 35a

36a thermostat assembly department 41 intakepories

42 relief openings

Claims

1. motor, it is to dispose water pump on cylinder head, with the pump side cooling water path that is formed on this water pump, is connected the motor on the lid side cooling water path that is formed on the aforementioned cylinder head, it is characterized in that,

Aforementioned cylinder head has:

The lid side assembly department of aforementioned water pump can be installed;

The drive portion of the aforementioned water pump of driving device on this lid side assembly department; With

Be located at aforementioned cover side assembly department diverse location on, the lid side opening portion of aforementioned cover side cooling water path;

Aforementioned water pump has:

Have the pump side assembly department that can be installed on the aforementioned cover side assembly department and the shell of aforementioned pump side cooling water path;

Be configured on the aforementioned pump side assembly department, by aforementioned pump side assembly department being installed on the aforementioned cover side assembly department pump shaft that can be connected with aforementioned drive portion;

By driving aforementioned pump shaft, can be via the liquor charging portion of aforementioned pump side cooling water path force feed cooling water; With

Be located on the aforementioned shell,, can be connected to pump side opening portion in the aforementioned cover side opening portion, aforementioned pump side cooling water path by aforementioned pump side assembly department is installed on the aforementioned cover side assembly department;

Aforementioned pump side assembly department and aforementioned cover side assembly department, with the side in aforementioned pump side opening portion and the aforementioned cover side opening portion, having can be along the mutual chimeric concaveconvex shape of the axle direction of aforementioned pump shaft, and the opposing party has along the attachment face of the direction vertical with respect to the aforementioned axis direction.

2. motor as claimed in claim 1 is characterized in that, aforementioned pump side assembly department and aforementioned cover side assembly department have can chimeric mutually aforementioned concaveconvex shape.

3. motor as claimed in claim 1 is characterized in that, is provided with intakeport on aforementioned cylinder head, and being provided with simultaneously becomes the thermostat assembly department to the discharge portion of the aforementioned cooling water of aforementioned cover side cooling water path supply from aforementioned cover side opening portion;

Aforementioned thermostat assembly department be formed on same plane of the opening portion of aforementioned intakeport or parallel position on.

4. motor as claimed in claim 1 is characterized in that, is the boundary with the camshaft of aforementioned cylinder head, is provided with intakeport in side's side, is provided with relief opening in the opposing party's side simultaneously;

And so that aforementioned cover side opening portion to be set in aforementioned exhaust side, near supply with aforementioned cooling water from this lid side opening portion the aforementioned relief opening of aforementioned cover side cooling water path mode constitutes.

5. motor as claimed in claim 4 is characterized in that, the opening portion of aforementioned relief opening is to tilt towards the mode of the direction of leaving from the aforementioned water pump axle direction with respect to camshaft.