JPH0988537A - Oil cooling structure of water-cooled engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently lubricate the inside of a cylinder head in the oil cooling structure of a water-cooled engine, by feeding oil whose temperature is more lower to the cylinder head without imparting a flow condition of cooling water. SOLUTION: In the oil cooling structure of a water-cooled engine 10, an outlet pipe 32 through which cooling water is passed is extended in left and right directions in the rear of a cylinder 16 and also equipped with a double pipe part 38, and a first oil pipe 44 which is upwardly extended from a crank case 14 and met with an outer pipe 38b is piped between the double pipe part 38 and the crank case 14. The cooling water is led to flow into an inner pipe 38a while oil fed through the first oil pipe 44 is led to flow into the annular passage of the double pipe part 38, and a second oil pipe 46 for leading the oil passed through the annular passage to a cylinder head 18 is piped between the outer pipe 38b and the cylinder head 18.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an oil cooling structure for a water-cooled engine.

[0002]

2. Description of the Related Art Generally, in a four-cycle engine, oil is pressurized by an oil pump driven by the engine itself, and the pressurized oil is forcibly fed to a friction portion in a cylinder head or a crankcase for oil supply.

FIG. 7 shows a lubrication path diagram of a conventional 4-cycle engine. As shown in FIG. 7, the oil that lubricates each part in the cylinder head a is supplied from the main gallery c in the crankcase b to the camshaft by the two left and right oil pipes e and e arranged behind the cylinder d. It is fed directly to the oil passage g on the rear side of f. An oil filter h for filtering oil is detachably provided on the side of the crankcase b.
A water-cooled oil cooler g is configured at the root portion of the. The oil flowing in and out of the oil filter h is cooled by the cooling water circulating in the core i of the water-cooled oil cooler g, as shown in FIG.

FIG. 9 shows a cooling path diagram in the engine for the cooling water circulating through the water-cooled oil cooler g. The cooling water that circulates in the water-cooled oil cooler g is the basic path of the cooling water (water pump j → cylinder d → cylinder head a).
→ Take a different route than the radiator k). That is, the cooling water enters the oil filter h through the water pipe m1 and the water pump j through the water pipe m2.
Return to

For cooling the oil using the cooling water, in addition to the water-cooled oil cooler g shown in FIGS. 7 to 9, for example, an oil cooler built in a water pipe (actually opened) Japanese Laid-Open Patent Application No. Sho 63-100163) and a radiator with an oil cooler built-in (Japanese Utility Model Laid-Open No. Sho 61-94648) are known.

[0006]

However, the above-mentioned conventional technique has the following problems. 1. In FIGS. 7 to 9, the oil that has passed through the water-cooled oil cooler g is sent to the cylinder head a after passing through the crank case b, so that the oil from the crank case b is reached before reaching the cylinder head a. Will be heated by the heat of. Especially when the engine is in a high temperature state, the oil once cooled is reheated. Therefore, it is conceivable to cool the oil with an oil cooler separately provided before sending it to the cylinder head a, but the cost increases due to the provision of the oil cooler. Therefore, it is desired that oil having a lower temperature be supplied to the cylinder head to ensure a proper oil film and then the sliding surface between the cam and the tappet in the cylinder head is lubricated.

[0007] 2. In the oil cooler disclosed in Japanese Utility Model Laid-Open No. Sho 63-100163, the installation of the oil cooler increases the flow resistance of the cooling water in the water pipe, so that the cooling water does not flow smoothly and the water pump is burdened. Further, since the cooling water flows outside the oil cooler, the diameter of the water pipe becomes large. On the other hand, the oil cooling device described in Japanese Utility Model Laid-Open No. 61-94648 has a problem that the structure of the radiator becomes complicated.

The present invention has been made in view of the above-mentioned problems of the prior art, in which oil having a lower temperature is supplied to the cylinder head and the inside of the cylinder head is satisfactorily lubricated without impairing the flow state of the cooling water. An object of the present invention is to provide an inexpensive oil cooling structure for a water-cooled engine.

[0009]

The present invention has the following configuration to achieve the above object. That is, the present invention provides a cylinder protruding from the front upper part of the crankcase, a cylinder head fixed to the upper end of the cylinder,
A water-cooled engine having a cooling path for sending cooling water from the cylinder head to a radiator, wherein oil is supplied from the crankcase to the cylinder head and the interior of the cylinder head is lubricated by the oil, The cooling path includes a portion extending in the left-right direction behind the cylinder, and a double-pipe portion including an inner pipe and an outer pipe is formed in the portion extending in the left-right direction.
A first oil pipe extending upward from the crankcase and intersecting with the outer pipe is piped between the double pipe portion and the crankcase, and between the inner pipe and the outer pipe, The oil sent from the crankcase flows through the first oil pipe, while cooling water flows in the inner pipe, and further, between the outer pipe and the cylinder head. A second oil pipe for guiding the oil passing between the inner pipe and the outer pipe to the cylinder head is provided, which is an oil cooling structure for a water-cooled engine.

According to the present invention, the oil in the crankcase is sent to the double pipe portion through the first oil pipe and passes between the inner pipe and the outer pipe, and then the second oil. It is supplied to the cylinder head by a pipe. At this time, the oil passing between the inner pipe and the outer pipe exchanges heat with the cooling water across the inner pipe. That is, in the double pipe portion, the oil removes heat from the cooling water and is cooled. As a result, the cooled cooling water having a lower temperature is supplied to the cylinder head by the second oil pipe.

Further, according to the present invention, since the cooling water is passed through the inner pipe of the double pipe portion, the cooling water flows smoothly through the cooling path as in the conventional case. Further, structurally, it is inexpensive because a part of the cooling water cooling path is formed as a double pipe.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a motorcycle according to this embodiment. FIG. 2 is a side view of the engine according to this embodiment. FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 is a rear view of the water pipe according to this embodiment. FIG. 5 is a partial cross-sectional view of the water pipe according to the present embodiment and is a view seen from the direction A in FIG. FIG. 6 is an oil system diagram according to the present embodiment.

In this embodiment, the oil cooling structure for a water-cooled engine according to the present invention is applied to a motorcycle. As shown in FIG. 1, the motorcycle 2 includes a 4-cycle parallel multi-cylinder engine (hereinafter referred to as an engine) 10 arranged between a front wheel 4 and a rear wheel 6 and below a fuel tank 8.
And a radiator 12 arranged near the front of the engine 10.

As shown in FIG. 2, the engine 10 has a crankcase 14 which rotatably supports a crankshaft therein.
A cylinder 16 protruding from the front upper part of the crankcase 14, a cylinder head 18 fixed to the upper end of the cylinder 16, and a head cover 20 fastened to the upper surface of the cylinder head 18. It A carburetor 22 that supplies the air-fuel mixture to the intake side of the cylinder head 18 is arranged behind the cylinder head 18.

As shown in FIG. 2, the radiator 12 is provided with a fan 12a on the back side thereof, and a water pump 24 provided on the lower side surface of the crankcase 12.
To the water pipe 26. The water pump 24 and the front surface of the cylinder 16 are connected by a water pipe 28 and an inlet pipe 30, and the inlet pipe 30 extends in the left-right direction on the front side of the cylinder 16 and is left-right as shown in FIG. The two outlets 30a and 30b communicate with a cooling passage such as a water jacket in the cylinder 16. On the other hand, behind the cylinder head 18, as shown in FIG. 3, outlet pipes communicating with the cylinder head 18 at two left and right introducing portions 32a and 32b (at a portion extending in the left-right direction of the cooling path according to the claims). (Corresponding) 32 is piped. The outlet pipe 32 includes the left and right introducing portions 32a, 3a.
It extends in the left-right direction between 2b and is connected to the water hose 34 (see FIG. 2) at the end portion on the right side with respect to the front of the vehicle. The water pipe 34 passes through the right side of the cylinder head 18 as shown in FIG.
It communicates with 2 through the thermostat 36.

The structure of the outlet pipe 32 will be described in detail. As shown in FIG. 4, the outlet pipe 32
Has its center part recessed slightly rearward so as to correspond to the outer shape of the back surface of the cylinder head 18, and the center part including this recess is formed as a double pipe. As shown in FIG. 5, the double pipe portion 38 is composed of an inner pipe 38a and an outer pipe 38b, and between the inner pipe 38a and the outer pipe 38b, there is a cross section that is substantially the same in the longitudinal direction. A ring-shaped passage 38c is formed. Left and right ends 38b1 and 38b of the outer tube 38b
2 reaches the vicinity of the introduction parts 32a and 32b, respectively, and are reduced in diameter in the vicinity and fixed to the outer peripheral surface of the inner pipe 38a.

As shown in FIG. 5, a lead-out pipe 40a is provided near the inner side of the left end portion 38b1 of the outer pipe 38b.
Communicates with the annular passage 38c through a hole 42a provided in the outer pipe 38b. On the other hand, in the vicinity of the inner side of the right end portion 38b2 of the outer pipe 38b, a downwardly projecting introduction pipe 40b is provided, and the introduction pipe 40b is provided with an annular passage through a hole 42b provided in the outer pipe 38b. Three
Connect to 8c.

Next, the oil cooling structure of this embodiment will be described. In this embodiment, oil is supplied from the crankcase 14 to the cylinder head 18, and the inside of the cylinder head 18 is lubricated by the oil. To supply the oil to the cylinder head 18, as shown in FIG. 2, a first oil pipe 44 arranged on the crankcase 14 side and a second oil pipe 46 arranged on the cylinder head 18 side are provided. used.

The first oil pipe 44 extends upward (in the engine height direction) from the upper wall of the crankcase 14 located substantially directly below the outlet pipe 32 in a side view of the vehicle (see FIG. 2) and is an outlet pipe. 32
Cross. The lower end of the first oil pipe 44 is fastened to the upper wall of the crankcase 14 with a union bolt 48, while the upper end is connected to the introduction pipe 40b of the outlet pipe 32.

As shown in FIGS. 2 and 3, one end of the second oil pipe 46 is connected to the outlet pipe 40a of the outlet pipe 32, and the left side of the second oil pipe 46 extends along the rear surface of the cylinder head 18 from the connecting portion. And the other end is fastened to the left side wall of the cylinder head 18 with a union bolt 50.

The operation of this embodiment having the above configuration will be described. First, the cooling water cooling path will be described, and then the oil lubrication path will be described. Radiator 12
As shown in FIG. 2, the cooling water cooled by 2 reaches the inlet pipe 30 through the water pipe 26 and the water pipe 28 by the water pump 24. The cooling water in the inlet pipe 30 is supplied to the left and right outlets 30a,
Cylinder 16 and cylinder head 18 via 30b
It is pressure-fed to the inner water jacket to cool the cylinder 16 and the cylinder head 18. Cylinder head 18
As shown in FIG. 3, the cooled oil flows into the outlet pipe 32 from the left and right inlets 32a and 32b, is guided to the right side, and returns to the radiator 12 through the water pipe 34 and the like. At this time, the cooling water that has flowed in from the left introduction portion 32a flows rightward through the inner pipe 38a of the double pipe portion 38 and reaches the water pipe 34.

On the other hand, the oil introduced from the main gallery or the like in the crankcase 14 to the upper wall of the crankcase 14 rises through the first oil pipe 44 as shown in FIG. The right end portion of the annular passage 38c is reached. The oil flowing into the right end portion of the annular passage 38c flows in the annular passage 38c toward the left side along the longitudinal direction thereof. The oil flowing toward the left side is guided to the left side wall of the cylinder head 18 by the second oil pipe 46 and enters into the cylinder head 18 through the union bolt 50, and thereafter, a predetermined oil passage, a cam shaft, etc. Lubricate the sliding surface between the cam and tappet.

According to the oil cooling structure of the present embodiment having the above-described structure and operation, in the double pipe portion 38, the cooling water passing through the inner pipe 38a and the annular passage 38c.
Since the oil passing therethrough exchanges heat via the peripheral wall of the inner pipe 38a, the oil warmed by the crankcase 14 is cooled by the heat of the cooling water and then cooled by the second oil at a lower temperature. Cylinder head 1 with the oil pipe 46 of
8 is supplied. Therefore, the sliding surface between the cam and the tappet in the cylinder head 18 can be lubricated with the oil at a lower temperature, and the abrasion of the sliding surface can be effectively suppressed. In the case of the present embodiment, the temperature of the cooling water taken out from the cylinder head 18 is about 80 ° C., and the temperature of the oil taken out from the crankcase 14 (the oil entering the annular passage 38c) is about 130 ° C. Therefore, even the cooling water immediately after cooling the cylinder 16 and the like has a cooling effect on the oil.

Further, according to the present embodiment, the flow direction of the cooling water and the flow direction of the oil in the double pipe portion 38 are opposite to each other, so that the heat exchange efficiency is good,
Therefore, the cooling effect on the oil is further improved.

Further, since the amount of oil supplied into the cylinder head 18 can be reduced by improving the lubrication action by lowering the temperature of the oil, a large amount of oil is turned to a thermally harsh portion of the crankcase 14 accordingly. It will be possible. That is, in FIG. 6, the portion where the heat exchange is performed (the portion where the double pipe portion 38 is provided) is the portion indicated by the symbol B, and the oil from the main gallery in the crankcase 14 to the portion indicated by the symbol B is shown. By reducing the amount of oil supplied to the piston, the amount of oil supplied from the main gallery to the thermally harsh piston or the like can be increased, and efficient oil lubrication (cooling) can be performed for the entire engine.

Further, according to the present embodiment, the cooling water is passed through the inner pipe 38a having substantially the same shape (inner diameter, etc.) as the conventional one, so that the cooling water does not impose a burden on the water pump 24, It flows through the outlet pipe 32 smoothly. Further, the structure is simple because the outer pipe 38b is fixed to the outer side of the inner pipe 38a, so that it is inexpensive.

The present embodiment is a preferred embodiment of the present invention, and the technical scope of the present invention is not limited to this embodiment.

[0028]

As described above, according to the present invention, oil having a lower temperature can be supplied to the cylinder head and the inside of the cylinder head can be satisfactorily lubricated without impairing the flow state of the cooling water.

[Brief description of drawings]

FIG. 1 is a side view of a motorcycle according to an embodiment.

FIG. 2 is a side view of the engine according to the present embodiment.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a rear view of the water pipe according to the present embodiment.

5 is a partial cross-sectional view of the water pipe according to the present embodiment, as viewed from the direction A in FIG.

FIG. 6 is an oil system diagram according to the present embodiment.

FIG. 7 is a diagram showing a lubricating path of oil in a conventional engine.

FIG. 8 is a diagram showing a cooling water cooling path and an oil path in a conventional oil filter.

FIG. 9 is a view showing a cooling water cooling path in a conventional engine.

[Explanation of Codes] 10 Engine 12 Radiator 14 Crankcase 16 Cylinder 18 Cylinder Head 32 Outlet Pipe (corresponding to the portion extending in the left-right direction according to claim 1) 38 Double pipe part 38a Inner pipe 38b Outer pipe 38c Circular passage (Corresponding to between the inner pipe and the outer pipe according to claim 1) 44 first oil pipe 46 second oil pipe

Claims (1)

[Claims] 1. A water-cooled engine comprising: a cylinder projecting from a front upper portion of a crankcase; a cylinder head fixed to an upper end of the cylinder; and a cooling path for sending cooling water from the cylinder head to a radiator. And supplying oil from the crankcase to the cylinder head to lubricate the inside of the cylinder head with the oil, wherein the cooling path includes a portion extending in the left-right direction behind the cylinder, and In the part that extends in the direction,
A double pipe portion including an inner pipe and an outer pipe is formed, and between the double pipe portion and the crankcase, a first oil pipe extending upward from the crankcase and intersecting with the outer pipe is formed. Oil sent from the crankcase through the first oil pipe flows between the inner pipe and the outer pipe, while cooling water flows in the inner pipe. Further, a second oil pipe for guiding the oil passing between the inner pipe and the outer pipe to the cylinder head is provided between the outer pipe and the cylinder head. Oil cooling structure for water-cooled engine.