JP2563534Y2 - Cylinder block of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a cylinder block of an internal combustion engine.

<Related Art> Recently, there has been an urgent need to reduce the weight of an internal combustion engine. For this reason, there is a cylinder block made of a light alloy instead of a cylinder block that has been manufactured with cast iron or the like.

By the way, the weight of the cylinder block made of light alloy is lighter, but the strength of the material itself is slightly smaller. For example, as shown in Japanese Utility Model Application Laid-Open No. 58-70442, various reinforcements are required to obtain the rigidity of the cylinder block. Has been made.

That is, as shown in FIGS. 7 and 8, a light alloy cylinder block 81 having an open upper end of a water jacket 82 is provided.
, A plurality of vertical ribs 85 extending vertically along the water jacket outer wall 83 and the skirt portion 84, and horizontal ribs 88 respectively extending along the bottom 86 and the lower deck 87 of the water jacket 82 in the front-rear direction. , 89 are formed integrally with the surface of the cylinder block 81 to increase the rigidity in the vertical and horizontal directions.

<Problem to be Solved by the Invention> Then, as shown in FIG. 9, head bolts (not shown) are formed in fastening holes 92 provided in cylinder walls 91 around cylinder bores 90a to 90d arranged at predetermined intervals. By inserting the cylinder head (not shown) into the cylinder block.
It is fastened to 81 top deck 93.

However, as shown in FIG. 10, the cylinder block 81 has a cylinder gasket (not shown) and a cylinder head 94.
When the head bolt 95 is mounted and fastened with the head bolt 95, the fastening force of the head bolt 95 is large near the head bolt 95, while it is small near the center of the cylinder bore 90. As described above, the vertical ribs 85, the horizontal ribs 88, 89
Even if these parts are provided, the ribs 85, 88 and 89 need to be finely provided in order to effectively transmit the fastening force of the head bolt 95, and they cannot be provided because they cause an increase in weight and cost. Therefore, the surface pressure generated between the bottom surface 96 of the cylinder head 94 and the top deck 93 of the cylinder block 81 is high near the head bolt 95 and low near the center of the cylinder bore 90. Therefore, the sealing performance of the cylinder gasket is reduced, and there is a possibility that lubricating oil and cooling water leak.

It is conceivable to increase the rigidity by increasing the thickness of the cylinder wall 91, but this also causes an increase in weight and cost.

The present invention has been made in view of such a conventional situation, and a cylinder of an internal combustion engine in which a sealing performance between a cylinder block and a cylinder head is improved by effectively exerting a head bolt fastening force. The purpose is to provide blocks.

<Means for Solving the Problems> For this reason, the present invention forms a water jacket around the cylinder bore, and provides a bolt fastening hole in a boss formed at a cylinder block side wall position corresponding to a space between adjacent cylinder bores. In a cylinder block of an internal combustion engine, a cylinder head is fastened to a top deck of a cylinder block by fitting a male thread portion of a head bolt inserted into a cylinder head to a female thread portion formed in the fastening hole. An oblique rib for fastening the top deck and the boss is provided on the outer surface of the block side wall, the upper end position of the oblique rib is a top deck position corresponding to substantially the center of the cylinder bore, and the lower end is substantially the upper end position of the female screw portion. ,
Vertical ribs for connecting the lower end of the boss and the lower deck of the cylinder block are provided, and the vertical ribs are formed of two-part thin ribs provided with a hollow portion at the center.

<Operation> According to this configuration, the fastening force of the head bolt is transmitted to the top deck located substantially at the center between the adjacent cylinder bores by the oblique ribs, so that the surface pressure of the top deck located on the outer periphery of the water jacket is equalized. Is done.

Further, since the lower end of the boss and the lower deck are connected via the vertical ribs, the fastening force of the head bolt is transmitted to the top deck located on the inner periphery of the water jacket via the vertical ribs, the lower deck, and the cylinder bore. In this case, since the vertical rib is formed of a two-part thin rib having a hollow portion at the center, the height of the vertical rib protruding from the side wall of the cylinder block is smaller than that of the vertical rib not divided into two parts. When the cross-sectional area is reduced, the increase in the weight of the cylinder block is suppressed and the fastening force of the head bolt is transmitted to the top deck on the inner periphery of the water jacket via the vertical ribs, the lower deck, and the cylinder bore. In addition, the transmission of the fastening force is performed more effectively, and the surface pressure of the top deck is made uniform.

Further, since the vertical ribs are formed of two-part type thin ribs having a hollow portion at the center, the distance between the thin ribs provided on adjacent bosses is reduced, and the vertical ribs are substantially centered. , The fastening force of the head bolt transmitted to the top deck position corresponding to the top deck increases, and uniformization of the surface pressure of the top deck is promoted.

In addition, since the hollow portion is formed at the center of the vertical rib, the thickness of the peripheral wall of the cylinder bore at the approximate center between adjacent cylinder bores is reduced, and casting defects are less likely to occur when manufacturing the cylinder block. At the same time, the residual stress is reduced.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

Embodiment shown in FIG. 1-FIG. 3 is a aluminum alloy cylinder block 1, inserting an iron liner 3 to the cylinder bore forming body 2 arranged at a predetermined interval L (hereinafter shows the center line C ₂₎ Is a dry liner model, and is a quadruple siamese cylinder in which adjacent cylinder bores 2 are connected. Further, the water jacket 4 has a water jacket structure in which an upper end is opened over a wide range, and a fastening hole 5 for fastening a cylinder head (not shown) is provided around the cylinder bore portion 2 and is inserted into the cylinder head. By fitting the male screw part 22 of the head bolt 6 to the female screw part 23 formed in the fastening hole 5,
A cylinder head is fastened to the top deck 7 of the cylinder block 1. Since the fastening hole 5 is provided around the cylinder bore 2, the boss 10 protrudes from the outer surface 8 of the cylinder block side wall, and the boss 10 is a two-part split type having a hollow portion at the center. The oil gallery 11 is connected to a lower deck 34 integrally formed by the thin rib 31.

Further, in the cylinder block 1 of the present embodiment, the top deck 7 has a plurality of upper decks 9 connecting the cylinder bore 2 and the cylinder block side wall outer surface 8 around each cylinder bore 2.

The cylinder block 1 has an oil passage 12 for supplying lubricating oil to a valve mechanism (not shown) provided in the cylinder head, and an oil passage for returning lubricating oil to an oil pan (not shown). Oil drop passages 13 are provided, and these passages 12 and 13 also have boss portions 14 formed on the outer surface 8 of the cylinder block side wall.

As the configuration according to the present invention, the top deck and the boss 10 or the boss 14 are provided on the outer surface of the side wall of the cylinder block.
Are provided. Here, the oblique rib 15 is, as shown in FIG.
Is located at the lower surface 7a of the top deck 7 on the outer surface 8 of the cylinder block side wall corresponding to substantially the center of the cylinder bore portion 2 (center line C ₂ ).

Here, the fastening hole 5 has an enlarged portion 21 (diameter φD, where d <D) having a diameter slightly larger than the diameter φd of the head bolt 6,
The head bolt 6 includes a female screw portion 23 that fits into a male screw portion 22 formed at the tip of the head bolt 6. The lower end portion 19 of the oblique rib 15 is located at the position of the substantially upper end portion 24 of the female screw portion 23.

 Next, the operation will be described.

First, the fastening force of a general bolt for each fastening location will be described. As shown in FIG.
The portion 63 closer to the base where the load is applied in the direction in which the load is applied is higher than the tip 62, and the load sharing ratio f is higher, thereby exerting a greater effect on the member to be fastened.

When the head bolt 6 is inserted into the fastening hole 5 and the cylinder head 27 is fastened to the cylinder block 1 via a cylinder gasket (not shown) or the like, the fastening force by the head bolt 6 is, as described above, the upper end. 24 is the largest, but since the lower end 19 of the oblique rib 15 is located at the position of the substantially upper end 24 of the female screw portion 23, the fastening force by the head bolt 6 is transmitted to the oblique rib 15 most efficiently. Further, the oblique rib 15 has an upper end portion 18 corresponding to a substantially center (center line C ₂ ) of the cylinder bore portion 2 and a cylinder block side wall outer surface 8.
Since the upper deck 7 is connected to the lower surface 7a of the top deck 7, the fastening force of the head bolt 6 is efficiently transmitted to the top deck 7 at a position corresponding to the center of the cylinder bore portion 2, and the transmitted fastening is thus performed. The surface pressure of the top deck 7 located on the outer periphery of the water jacket 4 is made uniform by the force.

Further, in the present embodiment, as shown in FIG. 1, the oblique rib 16 penetrates through the boss portion 14 with respect to the boss portion 14 formed by the oil passage 12 and the oil drop passage 13. The lower end 29 connects the boss 10 of the fastening hole 5. Further, since the lower end portion 29 is also located at the position of the substantially upper end portion 24 of the female screw portion 23, the fastening force of the head bolt 6 is efficiently transmitted to the top deck 7 between the head bolts 6 also with respect to the oblique rib 16. Is done. The oblique rib 16 at the portion penetrating the boss portion 14 is
It can be manufactured by splitting and casting a mold above and below.

Therefore, the head bolt 6 inserted into the cylinder head
By fitting the male screw part 22 of the cylinder head into the female screw part 23 formed in the fastening hole 5, the top deck 7 for fastening the cylinder head to the top deck 7 of the cylinder block 1 is formed.
Regarding the surface pressure acting between the upper surface and the lower surface of the cylinder head 27, there is no difference between the surface pressure in the vicinity of the head bolt 6 and the surface pressure in the vicinity of the center of the cylinder bore 2, thereby improving the sealing performance of the cylinder gasket. And
Leakage of lubricating oil and cooling water can be prevented.

In this embodiment, the oil passage is located near the # 2 cylinder.
12 and an oil drop passage 13 are provided.
In the vicinity of the two cylinders, the overhang from the outer surface 8 of the cylinder block side wall of the top deck 7 is large. Accordingly, by providing the reinforcing ribs 28, the surface pressure in the vicinity of the # 2 cylinder can be made more uniform, and the sealing performance can be improved, and the leakage of lubricating oil and cooling water can be further prevented.

Further, since the boss portion 10 is reliably connected to the lower deck 34 in which the oil gallery 11 is integrally formed by the thin rib 31, the fastening force of each head bolt 6 is not dispersed and the water is intensively passed through the lower deck 34. The power is transmitted to the top deck 7 located inside the jacket 4. Further, since the lower deck 34 has a substantially cylindrical cross section, its section modulus is large, and the rigidity of the cylinder block side wall outer surface 8 is also improved.

Incidentally, when the lower end of the boss portion 10 and the lower deck 34 are connected by thick ribs, it is difficult to reduce the weight of the cylinder block 1 and the fastening force of the head bolt 6 is dispersed. As a result, such fastening force cannot be intensively transmitted to the lower deck 34. In addition, since the blank 32 is provided between the two thin ribs 31, the above effect can be achieved while suppressing an increase in weight. In this case, the thickness of the peripheral wall of the cylinder bore portion 2 between the adjacent cylinder bore portions 2 becomes thinner, and when manufacturing the cylinder block 1, casting defects are less likely to occur, and residual stress is reduced to cause deformation after casting. It becomes difficult.

Also, as shown in FIG. 6, the boss portion 10 is connected to the lower deck 34 by the thin rib 33 on the cylinder block side wall outer surface 8 on the side where the oil gallery 11 does not pass. Forces are transmitted to each other via the lower deck 34, more evenly and effectively transmitted to the oblique ribs 15 and 16.

Since the boss 10 and the cylinder bore 2 are connected by the lower end 35 of the water jacket 4 in the cross-sectional direction of the cylinder block 1, the head bolt 6 is used as shown by an arrow F in FIG. The fastening force is also transmitted to the cylinder bore 2.

Further, since the vertical ribs for connecting the boss 10 and the lower deck 34 are formed from the two-part thin ribs 31 having a lightened part at the center, the cylinders are larger than the vertical ribs not divided into two parts. The height of the thin ribs 31 protruding from the side wall of the block 1 is reduced and the cross-sectional area is reduced, so that an increase in the weight of the cylinder block 1 is suppressed and the fastening force of the head bolt 6 is reduced. Lower deck
34 and the water jacket 4 through the cylinder bore 2
When transmitted to the top deck 7 on the inner periphery, the fastening force is transmitted more effectively, and the surface pressure of the top deck 7 is made uniform.

In addition to this, the vertical rib has a hollow portion at the center.
Since it is formed from the divided thin ribs 31, the distance between the thin ribs 31 provided on the adjacent boss portions 10 is reduced while minimizing the increase in weight, and the cylinder bore 2 is connected to the cylinder bore 2 via the lower deck 34. Water jacket 4 corresponding to almost the center
The fastening force of the head bolt 6 transmitted to the top deck 7 on the inner periphery is increased, and uniformization of the surface pressure is promoted.

Therefore, due to the synergistic effect of the oblique ribs 16 and the vertical ribs formed by the thin ribs 31, the surface pressure of the top deck 7 on the inner and outer circumferences of the water jacket 4 is made uniform, and the sealing performance of the top deck 7 is improved. In addition, leakage of lubricating oil and cooling water can be prevented.

In addition, since the cylinder block 1 of the present embodiment has the upper deck 9 that connects the cylinder bore portion 2 and the outer surface 8 of the cylinder block side wall in the top deck 7, each of the head bolts is 6 is directly transmitted to the cylinder bore portion 2 together with the upper deck 9, the surface pressure of the cylinder bore portion 2 is also uniform, and it is possible to prevent an uneven pressing force from acting on the cylinder gasket. There is also an effect that the gasket can be prevented from being blown through, and an increase in blow-by and a deterioration in oil consumption can be avoided.

In the case of a cylinder block having no upper deck 9, the rigidity of the top deck 7 and the outer surface 8 of the cylinder block side wall is greatly improved by the addition of the oblique ribs 15 and 16.
The surface pressure acting between the upper surface and the lower surface of the cylinder head becomes uniform, the sealing performance of the cylinder gasket is improved, and the effect of preventing leakage of lubricating oil and cooling water can be obtained.

<Effects of the Invention> As described above, according to the present invention, the oblique rib is provided on the outer surface of the cylinder block side wall, the upper end position of the oblique rib is a top deck position corresponding to substantially the center of the cylinder bore, and the lower end is the female screw portion. , The fastening force of the head bolt is transmitted to the top deck on the outer periphery of the water jacket corresponding to the substantially center of the cylinder bore, so that the surface pressure of the top deck located on the outer periphery of the water jacket is uniformized, The sealing performance of the top deck on the outer periphery of the water jacket is improved.

In addition, by providing a vertical rib connecting the lower end of the boss and the lower deck, and forming the vertical rib from a two-part thin rib provided with a hollow portion at the center, the weight increase of the cylinder block is suppressed as much as possible. At the same time, the fastening force of the head bolt is effectively transmitted to the top deck located on the inner periphery of the water jacket via the vertical ribs, the lower deck, and the cylinder bore, thereby improving the sealing performance of the top deck on the inner periphery of the water jacket.

Therefore, due to the synergistic effect of providing the oblique rib and the two-part vertical rib, the surface pressure of the top deck on the inner and outer circumferences of the water jacket is made uniform, the sealing performance of the top deck is improved, and lubricating oil and cooling are provided. There is an effect that leakage of water can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view of an aluminum alloy quadruple siamese cylinder block as one embodiment of a cylinder block of an internal combustion engine according to the present invention, FIG. 2 is a plan view of the same embodiment, FIG.
FIG. 4 is a perspective view of the same embodiment, FIG. 4 is a sectional view of a main part in FIG. 1, FIG. 5 is a view showing fastening force at each fastening position of the bolt, and FIG. FIG. 7 is a cross-sectional view of a conventional light alloy cylinder block, FIG. 8 is a side view of the conventional example, FIG. 9 is a perspective view of the conventional example, and FIG. FIG. 1 ... Cylinder block, 2 ... Cylinder bore, 5 ...
... fastening holes, 6 ... head bolts, 7 ... top deck,
8 ... outer surface of cylinder block side wall, 9 ... upper deck, 10, 14 ... boss, 15, 16 ... oblique rib, 18 ... upper end, 19, 29 ... lower end, 22 ... male screw part, 23 …… Female thread part, 27 …… Cylinder head, 31 …… Thin rib, 34 …… Lower deck

Claims (1)

(57) [Scope of request for utility model registration] A male screw portion of a head bolt inserted into a cylinder head, wherein a water jacket is formed around the cylinder bore, and a boss formed at a cylinder block side wall position corresponding to a space between adjacent cylinder bores is provided. By fitting the cylinder head to the top deck of the cylinder block by fitting the top deck and the boss on the outer surface of the side wall of the cylinder block. Are provided, the upper end position of the oblique rib is a top deck position corresponding to substantially the center of the cylinder bore, the lower end is substantially the upper end position of the female screw portion, and the lower end of the boss and the lower end of the cylinder block. A vertical rib is provided to connect to the lower deck, and A cylinder block for an internal combustion engine, wherein the cylinder block is formed from a two-part thin rib provided.