JPH059471Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention (1) Industrial application field This invention is a closed deck type Siamese cylinder block, particularly a Siamese cylinder block in which a plurality of adjacent cylinder barrels are connected to each other via a connecting part. a cylinder barrel, a cylinder block outer wall surrounding the Siamese cylinder barrel, a water jacket located between the Siamese cylinder barrel and the cylinder block outer wall and facing the outer periphery of the Siamese cylinder barrel, and a cylinder head joint surface side of the water jacket. The present invention relates to an improvement in a cylinder having a plurality of reinforcing deck portions that partially connect the Siamese cylinder barrel and the outer wall of the cylinder block at the end thereof.

(2) Prior Art Conventionally, in this type of Siamese cylinder block, the wall thickness of the reinforcing deck portion in the cylinder barrel axis direction is set to be equal for each reinforcing deck portion.

(3) Problems to be solved by the invention The temperature distribution around the cylinder bore during engine operation on the circumferential wall of the opening on the cylinder head joint surface side of each cylinder barrel is such that the temperature distribution around the cylinder bore is the highest because the connecting part is not sufficiently cooled by the cooling water. As the height increases and the distance from the connection point increases, the cooling effect of the cooling water increases, so the temperature tends to decrease.

Under the above circumstances, if the thickness of each reinforcing deck part is set equal as in the past, their cooling performance will be the same, so the reinforcing deck part close to the connecting part will have a lower amount of heat conduction from the cylinder barrel. Since there are many reinforcing deck parts, the temperature becomes high, but the reinforcing deck parts far from the connecting part have a low temperature because the amount of heat conduction from the cylinder barrel is small, and as a result, the temperature difference between each reinforcing deck part becomes large.

The deck connecting portion of each cylinder barrel peripheral wall is not in direct contact with the cooling water, so it is cooled via the reinforcing deck portion, but as mentioned above, if the temperature difference between each reinforcing deck portion is large, Accordingly, the temperature distribution in the circumferential direction of the circumferential wall of the cylinder barrel becomes non-uniform, which increases the variation in the amount of thermal expansion of each part of the circumferential wall of the cylinder barrel, causing problems such as deterioration of engine performance.

The present invention has been proposed in view of the above, and an object of the present invention is to provide a Siamese cylinder block that can solve the above-mentioned conventional problems.

B. Structure of the invention (1) Means for solving the problem According to the invention, in order to achieve the above object, the thickness of the plurality of reinforcing deck parts connected to the outer periphery of each outermost cylinder barrel in the axial direction of the cylinder barrel is increased. The thickness is set such that it becomes thicker as the distance from the connecting portion, which is present only on one side of each of the outermost cylinder barrels, increases, and a plurality of reinforcing deck portions are connected to the outer periphery of each intermediate cylinder barrel. The wall thickness of the cylinder barrel in the axial direction is set such that it becomes thicker at a position farther from the connecting portion on both sides of each intermediate cylinder barrel.

(2) Effect In both the outermost and middle cylinder barrels, the reinforcing deck part near the connection part receives a relatively large amount of heat from the cylinder barrel peripheral wall, but its wall thickness is relatively small compared to the above. The reinforcement deck part, which is far from the connecting part, is thin and easily cooled, so the temperature rise is suppressed as much as possible.On the other hand, the reinforced deck part, which is far from the connecting part, has a relatively thick wall and is not cooled, even though the amount of heat received from the cylinder peripheral wall is relatively small. Since it is difficult to use, the temperature drop can be suppressed as much as possible. As a result, the temperature difference between the plurality of reinforcing deck parts in each cylinder barrel is reduced, and the circumferential temperature distribution of each cylinder barrel peripheral wall connected to these reinforcing deck parts can be made as uniform as possible, so that the cylinder barrel peripheral wall Variations in the amount of thermal expansion of each part are suppressed as much as possible.

(3) Embodiment Figures 1 to 4 show an aluminum alloy closed deck type Siamese cylinder block S according to an embodiment of the present invention. ~
A Siamese cylinder barrel 1 in which adjacent ones of the fourth cylinder barrels _{1 1} to 1 ₄ are connected via a connecting part a, a cylinder block outer wall 2 surrounding the Siamese cylinder barrel 1, and a Siamese cylinder barrel 1 and a cylinder block outer wall 2 surrounding the Siamese cylinder barrel 1. Siamese cylinder barrel 1 located between cylinder block outer walls 2
Water jacket 3 facing the outer periphery of Water jacket 3
A plurality of reinforcing deck portions 4 partially connect the Siamese cylinder barrel 1 and the cylinder block outer wall 2 at the end on the side of the cylinder head joint surface b.
₁ to 4 ₄ , and a crankcase 7 connected to a Siamese cylinder barrel 1 and an outer wall 2 of the cylinder block. Adjacent reinforcing deck portions 4 ₁ ,
The space between 4 ₁ ; 4 ₁ , 4 ₂ ; 4 ₂ , 4 ₃ ; 4 ₃ and 4 ₄ functions as a communication port 5 to the cylinder head side.

Each cylinder barrel 1 ₁ to 1 ₄ is composed of an outer peripheral portion 1 a made of an aluminum alloy and a cast iron sleeve 1 b that is cast around the outer peripheral portion 1 a and defines a cylinder bore 6 .

As shown in FIG. 1 and FIG. 5b, the second cylinder barrel 1 is located in the middle of the cylinder barrel arrangement direction.
₂ , there are four first reinforcing deck portions 4 ₁ adjacent to both connecting portions a between it and the first and second cylinder barrels 1 ₁ and _{1 2} , and between both first reinforcing deck portions 4 _{1 .} Two second reinforcing deck portions 4 ₂ are provided which are located far away from the connecting portion a.

As shown by solid lines in FIG. 5c, in each of the first and second reinforcing deck portions 4 ₁ and 4 ₂ , each end surface c on the side of the cylinder head joint surface b is located on the same plane as the joint surface b, Each end face d on the side of the crankcase 7 is located on an inclined face e that gradually approaches the cylinder head joint face b from the end face d of the second reinforcing deck portion ₄₂ .

As a result, each of the first and second reinforcing deck portions 4 ₁ , 4 ₂
The temperature distribution in each second reinforcing deck portion 4 in the cylinder barrel axis direction is made uniform.
The wall thickness _T2 of ₂ is the wall thickness of each first reinforcing deck portion ₄₁ .
It is formed thicker than T ₁ (ie, T ₂ >T ₁ ).

In FIG. 5c, the first and second reinforcing deck portions 4 ₁ ′, 4 ₂ ′ indicated by chain lines are the conventional example, and the thickness T ₃ of each reinforcing deck portion 4 ₁ ′, 4 ₂ ′ is equal. It is set as follows. The wall thickness T ₃ is thicker than the wall thickness T ₁ of the first reinforcing deck portion 4 ₁ of the present invention, and thinner than the wall thickness T ₂ of the second reinforcing deck portion 4 ₂ (that is, T ₁
＜T ₃ ＜T ₂ ).

The temperature distribution around the cylinder bore during engine operation on the circumferential wall of the opening on the cylinder head joint surface b side of each cylinder barrel 1 ₁ to 1 ₄ is such that the temperature is highest at the connection part a because it is not sufficiently cooled by the cooling water. As the distance from part a increases, the cooling effect of the cooling water increases, so the temperature tends to decrease.

Figure 5a shows the connecting part a and the first and second reinforcing deck parts 4 ₁ , 4 ₁ '; 4 ₂ , 4 during engine operation.
₂ ', the solid line x corresponds to the present invention, and the dashed line y corresponds to the conventional example. t is the connecting part a
indicates the temperature of

In the present invention, as _shown by the solid line
Since T ₁ is thin and has good cooling performance, its temperature t ₁ is lower than that of the conventional example, even though the amount of heat conducted from the second cylinder barrel 1 ₂ to each first reinforcing deck portion 4 _{1 is} large. is kept lower than. On the other hand, since the wall thickness T ₂ of each second reinforcing deck portion 4 ₂ that is far from the connecting portion a is large and the cooling performance is reduced, the amount of water from the second cylinder barrel 1 ₂ to each second reinforcing deck portion 4 ₂ Although the amount of heat conduction is small, its temperature t ₂ is maintained higher than the temperature t ₂ ' of the conventional example.

As a result, the temperature difference Δt between the first and second reinforcing deck portions 4 ₁ and 4 ₂ becomes significantly smaller than Δt′ of the conventional example, and as a result, each deck connecting portion f of the second cylinder barrel 1 ₂ peripheral wall , g is reduced, variations in the amount of thermal expansion of each part of the second cylinder barrel ₁₂ can be suppressed as much as possible, and deterioration in engine performance due to such variations can be avoided.

Further, such effects are similarly achieved in the third cylinder barrel ₁₃ located in the middle in the cylinder barrel arrangement direction.

Furthermore, as shown in FIG. 1, there is a space around the first and fourth cylinder barrels 1 ₁ and 1 ₄ located at the outermost positions in the cylinder barrel arrangement direction, between them and the second and third cylinder barrels 1 ₂ and ₃ . two first reinforcing deck parts 4 ₁ that are close to both connecting parts a, two second reinforcing deck parts 4 ₂ that are sequentially further away from both connecting parts a, two third reinforcing deck parts 4 ₃ and One fourth reinforcing deck portion ₄₄ is provided.

In this case, the thicknesses of the first to fourth reinforcing deck portions 4 ₁ to 4 ₄ are formed so as to increase from the first reinforcing deck portion 4 ₁ to the fourth reinforcing deck portion 4 ₄ . Therefore, the first reinforcing deck portion 4 ₁ closest to the connecting portion a has the thinnest wall thickness, and the fourth reinforcing deck portion 4 ₄ being farthest from the connecting portion a.
The wall thickness is the thickest.

With this configuration, the same effects as described above can be obtained.

The present invention is also applicable to a closed deck type Siamese cylinder block in which the cylinder bore is defined by a fiber-reinforced composite made of a cylindrical fiber molded body and a light alloy matrix such as an aluminum alloy instead of the cast iron sleeve.

C. Effects of the invention According to the invention, the wall thickness in the cylinder barrel axis direction of the plurality of reinforcing deck parts connected to the outer periphery of each outermost cylinder barrel is the same as the barrel connection that exists only on one side of each outermost cylinder barrel. The wall thickness in the cylinder barrel axis direction of the plurality of reinforcing decks connected to the outer periphery of each intermediate cylinder barrel is The thickness of the reinforcement deck is set to be thicker as it is located further away from the barrel connecting parts on both sides of the cylinder barrel. Even though the amount of heat received from the peripheral wall is relatively large, the temperature rise can be suppressed as much as possible because the wall thickness is relatively thin and easily cooled as mentioned above.On the other hand, the reinforced deck part far from the connecting part Although the amount of heat received from the cylinder peripheral wall is relatively small, its wall thickness is relatively thick and difficult to cool down, so it is possible to suppress the temperature drop as much as possible.As a result, multiple reinforced deck parts in each cylinder barrel Reduce the temperature difference between them,
Since the circumferential temperature distribution of each cylinder barrel peripheral wall connected to the reinforcing deck part can be made as uniform as possible, the variation in the amount of thermal expansion of each cylinder barrel peripheral wall can be minimized, and the Siamese cylinder block can be incorporated. It can greatly contribute to improving the performance of the engine. Further, in each outermost cylinder barrel, the outer reinforcing deck portion, which bears a particularly large load, can be formed relatively thick, which is advantageous mechanically.

[Brief explanation of the drawing]

1 to 4 show a Siamese cylinder block according to an embodiment of the present invention, in which FIG. 1 is a perspective view seen from above, FIG. 2 is a sectional view taken along the line of FIG. Perspective view, Figure 4 is the second
Fig. 5 shows the shape and temperature distribution of the reinforcing deck part, a is a graph of the temperature distribution, b is a partially enlarged plan view of the Siamese cylinder block, and c is a cross section taken along the line C-C of b. It is a diagram. a... Connection part, b... Cylinder head joint surface,
T ₁ , T ₂ ... Wall thickness, 1 ... Siamese cylinder barrel, 1 ₁ - 1 ₄ ... 1st to 4th cylinder barrel, 2 ... Cylinder block outer wall, 3 ... Water jacket, 4 ₁ - 4 ₄ ...First to fourth reinforcing deck parts.

Claims (1)

[Scope of utility model registration request] A Siamese cylinder barrel 1 in which adjacent cylinder barrels 1 ₁ to _{1 4} are connected to each other via a connecting portion a, a cylinder block outer wall 2 surrounding the Siamese cylinder barrel 1, and the Siamese cylinder barrel 1. and a water jacket 3 located between the cylinder block outer walls 2 and facing the outer periphery of the Siamese cylinder barrel 1, and an end of the water jacket 3 on the cylinder head joint surface b side,
In the closed deck type Siamese cylinder block comprising a plurality of reinforcing deck parts 4 ₁ to 4 ₄ that partially connect the Siamese cylinder barrel 1 and the cylinder block outer wall 2, each of the outermost cylinder barrels 1 ₁ , 1 ₄ The wall thickness of the plurality of reinforcing deck parts 4 ₁ to 4 ₄ connected to the outer periphery of the cylinder barrel in the axial direction of the cylinder barrel is such that the wall thickness is far from the connecting part a that exists only on one side of each of the outermost cylinder barrels 1 ₁ , 1 ₄ . The wall thickness in the cylinder barrel axis direction of the plurality of reinforcing deck portions 4 ₁ , 4 ₂ that are continuous to the outer periphery of each intermediate cylinder barrel 1 ₂ , 1 ₃ is , a closed deck type Siamese cylinder, characterized in that the cylinder barrels 1 ₂ and 1 ₃ in the middle are arranged so that the thickness increases as the distance from the connecting portions a and a on both sides increases. Block.