JPH08200061A - Cooling water passage structure of water-cooled engine - Google Patents

Abstract

PURPOSE: To uniformly and properly distribute cooling water to respective cylinder assemblies by realizing a compact type of a cooling water passage to connect a water pump and water jackets of the cylinder assemblies to each other, also forming it easily and inexpensively, and improving efficiency of the water pump by reducing a pressure loss of the cooling water. CONSTITUTION: A cooling water passage 47 to connect water jackets 26 in respective cylinder assemblies 18A to 18C and a water pump 31 to each other, is formed in a crank case 17, and is made parallel to a row of the cylinder assemblies 18A to 18C. A cooling water passage structure is provided with a straight line-shaped cooling water main passage 48 penetrating through a delivery part 33 of the water pump 31 and plural cooling water distributing passages 49L and R to 5LL and R communicated with the water jackets 26 of the respective cylinder assemblies 18A to 18C by branching off in a straight line shape from this cooling water main passage 48.

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 in which a plurality of cylinder assemblies are arranged in series in a crankcase, and more specifically, a water pump is provided in the crankcase, and a water pump for each cylinder assembly is provided from the water pump. The present invention relates to a cooling water passage structure for a water-cooled engine in which a cooling water passage leading to a jacket is formed in a crankcase.

[0002]

2. Description of the Related Art Like a small water-cooled engine 100 shown in FIG. 7, a plurality of (two in this case) cylinder assemblies 102 are connected in series to a crankcase 101, that is, a crankshaft 103.
There is a water-cooled engine arranged in parallel to. Inside each cylinder assembly 102, a cylinder bore in which a piston (not shown) slides is formed, and a water jacket 104 is provided so as to surround the cylinder bore.

On the other hand, a water pump 105 is installed in the crankcase 101.
A suction part 106 and a discharge part 107 are provided at 5. The discharge part 107 is a cooling water passage formed in the crankcase 101.
The cooling water passage 108 is connected to the water jacket 104. The cooling water passage 108 is formed by providing a core having the same shape as the cooling water passage 108 inside the casting mold when the crankcase 101 is cast.

When the water-cooled engine 100 operates, the water pump 105 operates in synchronization with the rotation of the crankshaft 103, and the cooling water is sucked from the suction portion 106. The sucked cooling water is discharged from the discharge portion 107, flows through the cooling water passage 108, and the water jacket 1 of each cylinder assembly 102.
Drained to the drain pipe 1 after cooling the cylinder bore.
Drained from 09.

[0005]

However, this water-cooled engine 100 has the following problems because the cooling water passage 108 is formed by using the core during casting of the crankcase 101 as described above. are doing.

First, since the core forming the cooling water passage 108 is required to have a certain thickness or more, the passage shape of the cooling water passage 108 inevitably becomes large, which results in the dimensions of the crankcase 101. Increased water-cooled engine 100
It is inevitable to increase the size and weight.

Further, when the cooling water passage 108 is formed by using the core, the shape and size of the cooling water passage 108 are likely to vary, which causes a difference in the flow rate of the cooling water in each cylinder assembly 102. Cylinder assembly 102
May be unevenly cooled.

Further, due to the construction of the casting mold using the core, the shape of the cooling water passage 108 is variously restricted, and a smooth passage shape cannot be obtained. For this reason, the pressure loss of the cooling water increases, the efficiency of the water pump 105 decreases, and it is difficult to properly distribute the cooling water to each cylinder assembly 102.

In addition to this, by providing the core for the cooling water passage 108, the casting die becomes complicated and the cost of the casting die increases significantly.

The present invention has been made in order to solve such a problem, and a cooling water passage connecting a water pump and a water jacket of a cylinder assembly can be formed compactly, easily and inexpensively. At the same time, it is possible to reduce the pressure loss of the cooling water and improve the efficiency of the water pump, and at the same time, to provide the cooling water passage structure of the water-cooled engine, which is capable of uniformly and appropriately distributing the cooling water to each cylinder assembly. The purpose is to

[0011]

To achieve the above object, the cooling water passage structure for a water-cooled engine according to the present invention has a plurality of cylinder assemblies arranged in series in a crankcase as described in claim 1. In a water-cooled engine provided with a water pump, a cooling water passage connecting between the water jacket in each cylinder assembly and the water pump is formed in the crankcase in parallel with the row of the cylinder assembly. And a linear cooling water main passage that passes through the discharge part of the water pump, and a plurality of cooling water distribution passages that branch linearly from the cooling water main passage and communicate with the water jackets of the cylinder assemblies. Configured.

Further, as described in claim 2, all the cooling water distribution passages are arranged in parallel with each other.

Further, as described in claim 3, the inner diameter of the cooling water distribution passage is different for each cylinder assembly.

[0014]

According to the present invention, since the cooling water main passage and the cooling water distribution passage forming the cooling water passage are all linear, these passages are formed by machining such as drilling. be able to. Therefore, the cooling water passage becomes very compact, the size and weight increase of the water cooling engine can be avoided, and the cooling water passage can be easily and inexpensively formed.

Further, since the shapes of the cooling water main passage and the cooling water distribution passage are less likely to vary, the flow rate of the cooling water distributed to each cylinder assembly is made uniform, the cooling is made uniform, and the passage shape is made uniform. Since it is straight, the pressure loss of cooling water is reduced and the efficiency of the water pump is greatly improved.

Moreover, since the main cooling water passage itself penetrates the discharge part of the water pump, it is not necessary to provide a dedicated passage for connecting the main cooling water passage and the discharge part, and the entire structure of the cooling water passage is simplified. To be done.

If all the cooling water distribution passages are arranged in parallel as in claim 2, the cooling water main passage and the cooling water distribution passage are arranged in the same plane, so that the entire cooling water passage is formed. It becomes more compact, and there is no need to reset the relative angle between the drill and the crankcase when the cooling water distribution passage is formed by drilling, and workability is greatly improved.

Further, if the inner diameter of the cooling water distribution passage is made different for each cylinder assembly as in claim 3,
The cooling water flow rate can be set individually for each cylinder assembly, and proper cooling water distribution can be performed in accordance with the heat quantity of each cylinder assembly.

[0019]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a right side view of a small snow vehicle equipped with a water-cooled engine according to the present invention.

In this small snow vehicle 1, a pair of left and right sliding sledges 3 are rotatably mounted on the lower front portion of a vehicle body 2 extending in the front-rear direction, and a drive unit 4 is provided on the lower rear portion of the vehicle body 2. ing. The drive device 4 includes, for example, a drive wheel 5 arranged in front of the device and a driven wheel 6 arranged in the rear of the device.
A plurality of intermediate wheels 7, a suspension mechanism 8, and an endless track 9 wound around the wheels 5 to 7.

A seating seat 11 is installed on the upper part of the vehicle body 2, and steps 12 lower than the seating seat 11 are provided on both left and right sides thereof. In front of the seat 11, a handlebar 13 for steering the sliding sled 3 to the left and right, and a windshield 14 are provided.

On the other hand, a water-cooled engine 16 is provided on the front of the vehicle body 2.
The power of the water-cooled engine 16 is transmitted to the drive wheels 5 of the drive unit 4 via a power transmission device (not shown), and the drive wheels 5 drive the endless track 8 to drive the small snow vehicle 1. It is designed to let you.

The occupant of the small snowmobile 1 sits on the seat 11 and puts his / her feet on the left and right steps 12, grips the handlebars 13 with both hands and steers the sliding sled 3, and then the water-cooled engine.
The output of 16 is controlled, and the traveling direction and traveling speed of the small snow vehicle 1 are determined and the vehicle travels.

FIG. 2 is a water-cooled engine viewed from the direction of arrow II in FIG.
16 is a front view of FIG. 3, and FIG. 3 is a vertical cross-sectional view of the water-cooled engine 16 taken along the line III-III of FIG. 2. This water-cooled engine 16
For example, it is a two-cycle three-cylinder engine, and three cylinder assemblies 18A to 18C are arranged in series along the longitudinal direction of the crankcase 17.

The crankcase 17 is constructed by combining, for example, an upper case 17a on the upper side and a lower case 17b on the lower side, and a crankshaft 19 is pivotally supported therein. A cylinder base 20 for fixing the cylinder assemblies 18A to 18C is provided on the upper surface of the upper case 17a so as to be slightly inclined forward, and an intake manifold to which a carburetor (not shown) is connected is provided on the rear side of the cylinder base 20. 21 are provided.

On the other hand, the cylinder assemblies 18A-18
C includes a cylinder block 23 fixed on the cylinder base 20 and a cylinder head 24 fixed thereon. In addition, 25 is a spark plug.

Inside the cylinder block 23, there is formed a cylinder bore in which a piston (not shown) slides, and a water jacket 26 is provided so as to surround the cylinder bore. An exhaust port 27 is provided on the front side of the cylinder block 23, and the exhaust muffler 28 shown in FIG. 1 is connected to the exhaust port 27. The crankcase
A cylindrical casing 29 is continuously provided on the right side of 17, and auxiliary devices such as a generator, an ignition device, and a flywheel are built therein.

A water pump 31 for sending cooling water to the water jacket 26 is installed on the front surface of the crankcase 17. The water pump 31 is, for example, a spiral type pump, and is configured as follows.

First, a pump chamber is provided on the front surface of the lower case 17b.
32 is recessed, and a discharge portion 33 extending tangentially from the pump chamber 32 is carved from the lower case 17b to the upper case 17a. The end portion of the discharge portion 33 is formed, for example, in a cylindrical hole shape extending toward the crankshaft 19 side in a plan view.

Then, the pump cover 35 is fixed in a liquid-tight manner from the front of the pump chamber 32 and the discharge part 33 by using several screws 34. A union-shaped suction portion 36 is integrally formed with the pump cover 35.

On the other hand, in the lower case 17b, a pump shaft 38 orthogonal to the crank shaft 19 in plan view is rotatably supported by bearings 39 and 40, and the front end portion of the pump shaft 38 is in the pump chamber 32. An impeller 41 extends inwardly and is fixed to the front end portion by a bolt 42 so as to rotate together. Wings 43 extending radially are integrally formed on the front surface of the impeller 41.

A driven screw gear is provided at an intermediate portion of the pump shaft 38.
45 is provided, and this driven screw gear 45 is a crankshaft.
It meshes with a driving screw gear 46 provided in the middle portion of 19. Therefore, when the water-cooled engine 16 operates, the pump shaft 38 rotates in conjunction with the rotation of the crank shaft 19 and the impeller
The cooling water is sucked into the pump chamber 32 from the suction part 36 by turning around 41, and the sucked cooling water is discharged from the discharge part 33.

The water pump 31 configured as described above
Is connected to the water jacket 26 in each of the cylinder assemblies 18A-18C via a cooling water passage 47 having the structure according to the present invention. The cooling water passage 47 includes a cooling water main passage 48 formed in the upper case 17a and a plurality of cooling water distribution passages 49L, R to 51L, which branch from the cooling water main passage 48 and communicate with each water jacket 26. It is configured with R.

As shown in FIG. 4, the cooling water main passage 48 is also provided.
Extends linearly along the front surface of the upper case 17a so as to be parallel to the rows of the cylinder assemblies 18A to 18C, and the intermediate portion thereof penetrates the end portion of the discharge portion 33 of the water pump 31. As shown in FIG. 5, both ends of the cooling water main passage 48 are liquid-tightly closed by plugs 53.

Further, the cooling water distribution passages 49L, R to 51L, R
For example, six are formed in total, each of which extends linearly from the cooling water main passage 48 and opens on the upper surface of the upper case 17a (the upper surface of the cylinder base 20).
These cooling water distribution passages 49L, R to 51L, R have two cooling water distribution passages 49 in the water jacket 26 of one cylinder assembly 18 when the cylinder assemblies 18A to 18C are installed on the upper surface of the upper case 17a. Are connected from below. Here, the cooling water distribution passage 49L,
R to 51L and R are all arranged in parallel with each other.

The cooling water discharged from the discharge part 33 of the water pump 31 is supplied from the cooling water main passage 48 to each cooling water distribution passage 49.
Cylinder assembly 18A to 18C through L, R to 51L, R
After being distributed to the water jacket 26, the water is drained from the drain pipe 54 provided at the rear of each cylinder assembly 18A to 18C as shown in FIG. The drain pipe 54 and the suction part 36 of the water pump 31 are connected by a cooling water hose (not shown), and the cylinder assembly 18A to 18A is connected by a radiator connected in the middle of the cooling water hose.
The heat exchange of the cooling water that has cooled C is performed.

In the case of the cooling water passage structure according to the present invention, the cooling water main passage 48 and the cooling water distribution passage 49 which constitute the cooling water passage 47.
Since L, R to 51L, R are all formed linearly, these passages can be formed by machining such as drilling. Therefore, the cooling water passage 47 is
The width of the 17 (upper case 17a) in the front-rear direction is eliminated, and the size of the water-cooled engine 16 is increased.
Is extremely easy and inexpensive.

Further, since the shapes of the cooling water main passage 48 and the cooling water distribution passages 49L, R to 51L, R are less likely to appear, the flow rate of the cooling water distributed to the water jacket 26 of each cylinder assembly 18A to 18C is reduced. The cooling water becomes uniform and the cooling becomes uniform, and the pressure loss of the cooling water decreases due to the straight passage shape, which greatly improves the efficiency of the water pump 31.

Moreover, since the cooling water main passage 48 itself penetrates the discharge part 33 of the water pump 31, the cooling water main passage is formed.
It is not necessary to provide a dedicated passage that connects 48 and the discharge unit 33.
Therefore, the overall configuration of the cooling water passage 47 can be simplified.

Furthermore, since it is not necessary to provide a core having a complicated shape inside the crankcase casting mold in forming the cooling water passage as in the conventional case, the cost of the casting mold can be kept low. Even when the cooling water passage 47 is formed as a casting hole, since a core having a complicated shape is unnecessary,
The cooling water passage 47 can be easily and inexpensively formed.

Further, in the present invention, all the cooling water distribution passages are provided.
Since 49L, R to 51L, R are arranged in parallel, the cooling water main passage 48
And the cooling water distribution passages 49L, R to 51L, R are arranged in the same plane. For this reason, the entire cooling water passage 47 is
It is more compact in the front and rear direction of the crankcase 17
This can further contribute to downsizing of the (upper case 17a). Moreover, the cooling water distribution passages 49L, R ~ 51 can be drilled.
When forming L and R, it is not necessary to reset the relative angle between the drill and the upper case 17a, and the workability is greatly improved.

By the way, FIG. 6 is a front view of an upper case 17a showing another embodiment of the present invention. As shown here, the inner diameters of the cooling water distribution passages 49L, R to 51L, R are made different for each of the cylinder assemblies 18A to 18C. By doing this, each cylinder assembly 18A-
18C cooling water flow rate can be set individually,
Appropriate cooling water distribution corresponding to the amount of heat of each cylinder assembly 18A-18C can be performed.

For example, in the example of FIG. 6, the water pump 31
The cooling water distribution passages 49L and R on the cylinder assembly 18A side, which is the closest to the discharge portion 33 and which can obtain a high cooling water discharge pressure, are formed thin, and the cylinder assembly 18C side that is the farthest from the discharge portion 33 and has the low cooling water discharge pressure Cooling water distribution passage 51L,
R is thickly formed. As a result, the cooling water is evenly distributed to the cylinder assemblies 18A to 18C, and uniform cooling is performed.

Not limited to the example of FIG. 6, for example, the cooling water distribution passage connected to the cylinder assembly having a large heat quantity may be formed thick and the cooling water distribution passage connected to the cylinder assembly having a small heat quantity may be formed thin.

Further, each cylinder assembly 18A-18
The left and right passage diameters of the two cooling water distribution passages 49L, R to 51L, R connected to C can be made different. By doing so, the cooling water circulates around the cylinder bore in the water jacket 26 in a fixed direction, and efficient cooling can be performed.

By the way, the water-cooled engine in this embodiment
The cylinder assembly 18 has the cylinder assemblies 18A to 18C formed separately and provided on the crankcase 17. For example, a plurality of cylinder bores are formed in one long cylinder block, and the cylinder bores are formed around each cylinder bore. The cooling water passage structure according to the present invention can also be applied to a water-cooled engine having a structure provided with a water jacket.

Further, although the water-cooled engine 16 in this embodiment is a serial engine, the cooling water passage structure according to the present invention can be applied to, for example, a V-type engine provided with a plurality of cylinder bores along the crankshaft or a horizontally opposed engine. Can be applied.

[0048]

As described above, the cooling water passage of the water-cooled engine according to the present invention is a water-cooled engine in which a plurality of cylinder assemblies are arranged in series in a crankcase and a water pump is provided. A cooling water passage that connects between the water jacket in the assembly and the water pump is formed in the crankcase, is parallel to the row of the cylinder assembly, and is a linear cooling penetrating the discharge portion of the water pump. A main water passage and a plurality of cooling water distribution passages that branch from the main cooling water passage in a straight line and communicate with the water jackets of the cylinder assemblies are provided.

As described above, since the main cooling water passage and the cooling water distribution passage constituting the cooling water passage are all linear, these passages can be formed by machining such as drilling. Therefore, the cooling water passage becomes very compact, the size and weight increase of the water cooling engine can be avoided, and the cooling water passage can be formed very easily and inexpensively.

Since the shapes of the cooling water main passage and the cooling water distribution passage are unlikely to vary, the flow rate of the cooling water distributed to each cylinder assembly is made uniform, the cooling is made uniform, and the passage shape is made uniform. Since it is straight, the pressure loss of the cooling water is reduced, and the efficiency of the water pump can be greatly improved.

Moreover, since the main cooling water passage itself penetrates the discharge portion of the water pump, it is not necessary to provide a dedicated passage for connecting the main cooling water passage and the discharge portion, and the structure of the entire cooling water passage is simplified. be able to.

Further, in the cooling water passage of the water-cooled engine according to the present invention, since the cooling water distribution passages are all arranged in parallel with each other, the cooling water main passage and the cooling water distribution passage are arranged in the same plane. Therefore, the entire cooling water passage is made more compact, and it is not necessary to reset the relative angle between the drill and the crankcase when the cooling water distribution passage is formed by drilling, resulting in very good workability.

Further, in the cooling water passage of the water-cooled engine according to the present invention, the inner diameter of the cooling water distribution passage is made different for each cylinder assembly, so that the cooling water flow rate can be set individually for each cylinder assembly. Therefore, it is possible to properly distribute the cooling water in proportion to the heat quantity of each cylinder assembly.

[Brief description of drawings]

FIG. 1 is a right side view of a small snow vehicle equipped with a water-cooled engine according to the present invention.

FIG. 2 is a front view of the water-cooled engine showing the first embodiment of the present invention as viewed from the direction of arrow II in FIG.

FIG. 3 is a longitudinal sectional view of the water-cooled engine taken along the line III-III in FIG.

FIG. 4 is a front view of the upper case taken along the line IV of FIG.

5 is a cross-sectional view of the upper case taken along the line VV in FIG.

FIG. 6 is a front view of an upper case showing another embodiment of the present invention.

FIG. 7 is a front view of a water-cooled engine showing a conventional technique.

[Explanation of symbols]

 1 Small snow vehicle 16 Water-cooled engine 17 Crankcase 18A-18C Cylinder assembly 19 Crankshaft 26 Water jacket 31 Water pump 32 Pump chamber 33 Discharge part 35 Pump cover 36 Suction part 38 Pump shaft 41 Impeller 47 Cooling water passage 48 Cooling water main passage 49L, R ~ 51L, R Cooling water distribution passage

Claims (3)

[Claims] 1. A water-cooled engine in which a plurality of cylinder assemblies are arranged in series in a crankcase and a water pump is provided, and a cooling water passage connecting a water jacket in each cylinder assembly and the water pump. A linear cooling water main passage that is formed in the crankcase and that is parallel to the row of the cylinder assembly and that penetrates the discharge portion of the water pump; and a linear cooling water main passage that branches from the cooling water main passage. A cooling water passage structure for a water-cooled engine, comprising: a plurality of cooling water distribution passages communicating with a water jacket of a cylinder assembly. 2. The cooling water passage structure for a water-cooled engine according to claim 1, wherein all the cooling water distribution passages are arranged in parallel with each other. 3. A cooling water passage structure for a water-cooled engine according to claim 1 or 2, wherein the inside diameter of said cooling water distribution passage is different for each cylinder assembly.