JPS5840249Y2 - Cylinder head cooling system for air-cooled engines installed in agricultural mobile machines - Google Patents

Description

[Detailed description of the invention] The present invention relates to a cooling system for the cylinder head of an air-cooled engine mounted on an agricultural mobile machine.In particular, in a forced air-cooled engine mounted on an agricultural harvester, combustible materials such as straw This harmonizes the prevention of adhesion and accumulation on the cylinder head with the improvement of uniform cooling performance over the entire upper surface of the cylinder head.

Generally, in a forced air-cooled engine, the cooling air generated by a cooling fan is guided along the inner surface of the spiral case to cool not only the cylinder body but also the cylinder head. In addition to the spiral case 1, a head cover 3 that covers the cylinder head 2 is arranged at a close distance to the cooling fins 4 on the upper part of the cylinder head 2, which can suppress the diffusion of cooling air. Although there is an advantage that the cylinder head 2 can be appropriately cooled by the cooling air flowing between the fins 4, when the engine is installed in an agricultural harvesting machine such as a harvester or combine harvester, it is difficult to avoid combustible materials such as straw waste. It adheres and accumulates on the rad cover 3 of the cylinder, and the same head 2
There is a risk of burning due to the radiant heat from the cooling air, and dust such as pieces of straw that are mixed into the cooling air and guided by the air will be caught on the cooling fins 4, and the mutual gap between the fins 4 and the helad cover 3 will be reduced. It adheres and accumulates inside the cylinder in the form of a clogging, which poses the risk of burning, and also has the drawback of deteriorating the cooling effect of the cylinder head 2.

In addition, in view of this problem, as shown in Figure 1 H, Figure 1 ■
There is also a cylinder in which the rad cover 3 is abolished, the spiral case 5 is curved into an arc shape with a large radius of curvature, and its upper end is partially covered with a large distance from the cylinder head 6. In this conventional example, combustible materials such as straw that may adhere to and accumulate on the inner and outer surfaces of the cylinder head 6 can be dissipated by cooling air from the cooling fan 7, but on the other hand, the spiral case 5 has a large radius of curvature, and covers only a part of the upper surface of the cylinder head 6 while maintaining a close gap with the upper end of the cylinder head 6. Therefore, the cooling air from the cooling fan 7 is directed toward the cylinder head. This causes the disadvantage that the entire upper part of the cylinder head 6 cannot be cooled uniformly.

The present invention takes advantage of the advantages of each of the above-mentioned figures 1 and 2, eliminates the disadvantages of each, and prevents flammable materials such as straw from adhering to the inner and outer surfaces of the cylinder head. It was devised to combine this with the improvement of uniform cooling performance over the entire upper surface of the cylinder head, and its features are as follows: The air-cooled engine is forcedly cooled by the cooling air generated by the cooling fan and guided by the spiral case, so that the upper surface of the cylinder head is exposed substantially entirely, and the cooling air outlet end of the top wall of the spiral case is pressed. is located above one end of the upper surface of the cylinder head while leaving a certain opening between the upper surface of the cylinder head and the upper surface of the cylinder head through which combustible materials such as pieces of straw can pass; The windward side of the inner surface of the top wall is gradually inclined upward at a certain angle from an imaginary parallel line to the upper surface of the cylinder head.

The present invention will be explained in detail below based on the embodiments shown in Figures 2 and 3. Figure 2 shows a harvester as a self-propelled threshing machine, which is a mobile agricultural machine, equipped with a forced air cooling engine. , 10 is a harvester body, its chassis 11
is supported by rubber crawlers 12.

13 is a reaping device installed on the fuselage 10, 14 is a control device, 15 is a threshing device, and 16 is a pilot's seat.On the chassis 11, which occupies a lower position, there is a forced air-cooled engine as shown in Fig. 3. It is installed.

In addition, 17 in FIG. 2 is a fuel tank.

In Figure 3, 18 is the engine body of the above type, 19
20 is a flywheel fan pivotally supported using the protruding end of the crankshaft 21, and 22 is a fan case or spiral case of the fan 20, which covers the air introduction window 23. A cylindrical starter support mounting case 24 is assembled to the spiral case 22.

Reference numeral 25 denotes an air introduction hole formed in the mounting case 24, and a dustproof net 26 is stretched over this.

Although not shown, a coil starter is installed inside the mounting housing 24.

Further, 27 is a cylinder, 28 is a cylinder head,
Both 27 and 28 are equipped with the required number of cooling fins 29, and the upper surface of the cylinder head 28 is substantially entirely exposed to the outside world, and the upper surface of the cylinder head 28 is provided with vertical cooling fins. Fins 29 are arranged in rows, and spark plugs 30 are installed.

In order to cool not only the cylinder 27 but also the cylinder head 28 in particular, the flywheel fan 20 generates an air inlet hole 25 in the recoil starter mounting case 24 and an air inlet window in the spiral case 22. The cooling air introduced through the spiral case 23 is forcedly distributed in a directional and guided manner toward the upper surface of the cylinder 27, especially the cylinder head 28, using the inner surface of the spiral case 22 as a cowling. The form of the case 22 is configured in relation to the cylinder head 28 as follows.

That is, in the vertical cross-sectional shape shown in FIG. 3, the spiral case 22 integrally includes an upright side wall surface 22a and a substantially horizontal top wall surface 22b.
A part of the corner with b is bent at a substantially right angle through an arc with a relatively small radius of curvature, and more specifically, the upper surface of the cylinder head 28 and the top wall surface 2
A ventilation opening 31 of a size that allows combustible materials such as pieces of straw to pass through is provided between the cooling air/output end 32 of the cylinder head 2b, and the cooling air outflow end 32 is connected to one end of the upper surface of the cylinder head 28. The cooling fins 29 are positioned upward, and the openings 31 are oriented in the longitudinal direction of the vertical cooling fins 29.

In addition, in particular, the top wall surface 22 of the spiral case 22
b, so that the cooling air flowing through the interior and flowing out from the opening 31 does not diffuse, and can intensively cool the entire upper surface of the cylinder head 28 in a cleaning manner along the upper surface of the cylinder head 28; A state where the top wall surface 22 is directed toward the peripheral edge of the cylinder head 28 beyond the spark plug 30, that is, the top wall surface 22 is directed toward the imaginary line α parallel to the upper surface of the cylinder head 28.
The windward side of the inner surface b is set to be gradually inclined upward by a certain angle θ.

According to the present invention, firstly, since the cooling air sending end 32 of the top wall surface 22b is positioned above one end of the upper surface of the cylinder head 28, there is no Rad cover for the cylinder on the upper surface of the cylinder head 28, and the upper surface is Because it is exposed to the outside world,
Operations such as repairing the cylinder head 28 and inspecting/replacing the spark plug 30 can be easily performed, and there is a risk that the cylinder rad cover will be heated by the cylinder head 28 and the straw, etc. that falls onto the cover will burn. This is beneficial from a safety point of view.

Second, even though the cylinder head 28 is exposed as described above, there is a risk that combustible materials such as straw that scatter and fall onto the top surface of the cylinder head 28 may adhere or accumulate, causing a fire. Since the spiral case 22 has the windward side of the inner surface of the top wall surface 22b gradually inclined upward at a certain angle from an imaginary parallel line to the upper surface of the cylinder head 28, the cooling guided by the spiral case 22 The wind is blown onto the upper surface of the cylinder head 28 to clean any combustible materials, so there is no room for combustible materials to adhere to the upper surface of the cylinder head 28, and the above-mentioned dangers are prevented.

Furthermore, since the openings 31 are oriented in the longitudinal direction of the vertical cooling fins 29 arranged in a row on the cylinder head 28, the cooling air passes over the entire outer surface of the cooling fins 29, which reduces the cooling efficiency. In addition, combustible materials such as straw that scatter and fall onto the upper surface of the cylinder head 28 are moved in the longitudinal direction of the cooling fins 29 by the cooling air, so that the straw and other debris are caught on the fins 29. As a result, the chance of adhesion and accumulation on the upper surface of the cylinder head 28 is greatly reduced, and therefore, the risk of burning straw and the like on the cylinder head 28 due to the radiant heat is more reliably avoided.

Thirdly, there is a fixed opening 3 between the cooling air sending end 32 of the top wall surface 22b and the upper surface of the cylinder head 28 through which combustible materials can pass.
1, the pieces of straw that may be sucked in by the cooling fan 20 do not get caught in the openings 31, but instead pass through the fixed openings 31 between the top wall surface 22b and the upper surface of the cylinder head 28, and pass through the engine body 18. This invention can be said to be advantageous for use in an air-cooled engine mounted on an agricultural harvester, especially in an atmosphere where there is a lot of scattering of straw waste, etc., since the air is emitted to the outside and the overall structure is simplified.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of the conventional example, Figure 2 shows the object to which the present invention is applied...--An overall schematic side view of Bester, and Figure 3 is a cutaway of the main part showing the cooling device according to the present invention. FIG. 18...Engine body, 20...Cooling fan (flywheel fan), 22...Spiral case, 2
2a... Side wall surface, 22b... Top wall surface, 27... Cylinder, 28... Cylinder head, 29... Cooling fin, 31... Ventilation opening, 32... Guide piece, θ...
・Constant inclination angle.

Claims (1)

[Scope of utility model registration request] In an air-cooled engine in which the upper surface of the cylinder head, on which vertical cooling fins are arranged, is forcedly cooled by cooling air generated by a cooling fan and guided by a spiral case, substantially the entire upper surface of the cylinder head is At the same time, the cooling air sending end of the top wall of the spiral case is positioned above one end of the top surface of the cylinder head while leaving a certain opening between it and the top surface of the cylinder head through which combustible materials such as pieces of straw can pass. and the opening is oriented in the longitudinal direction of the vertical cooling fin, and the windward side of the inner surface of the top wall surface is gradually inclined upward at a certain angle from a virtual parallel line to the upper surface of the cylinder head. Features: Cylinder head cooling system for air-cooled engines mounted on agricultural mobile machines.