JPS6218678Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder block for a water-cooled engine that is provided with a water jacket between a cylinder portion in which a piston moves reciprocally and an outer wall of the block.

It has been well known that in multi-cylinder water-cooled engines, when the cylinder head is tightened and fixed with a gasket interposed on the upper surface of the cylinder block, undesirable deformation occurs in the cylinder block, particularly in the cylinder section. (For example, it is described in Japanese Patent Publication No. 51-25523.)

That is, the gasket is formed so that the grommet part around the opening corresponding to the inner diameter of the cylinder part has greater rigidity than other parts so that high-pressure combustion gas can be sealed at the grommet part. . Therefore, when the cylinder head is tightened with a large number of mounting bolts with the above-mentioned gasket interposed, the surface pressure of the grommet part, which has high rigidity, will be greater than that of other parts, and the peripheral edge of the upper end of the cylinder bore of the cylinder block will be The tightening pressure acting on the mounting bolt is greater than that on other parts, and the central cylinder part receives a compressive load relative to the mounting bolt, and the outer wall of the outer block deforms under a tensile load.

When the cylinder block is deformed as described above, the roundness and straightness of the cylinder part become out of order, which adversely affects the sliding contact between the inner peripheral surface of the cylinder part and the piston.
This has problems such as deterioration of the durability of pistons and the like and generation of noise.

In order to solve the above-mentioned problems, conventional examples of cylinder block structures that reduce deformation of the cylinder block, particularly deformation of the cylinder portion, are shown in FIGS. 1 to 3. The illustrated cylinder block is for a four-cylinder engine, and has a piston (not shown) inside.
Four cylinder parts 1a to 1d that reciprocate up and down
The cylinder parts 1a to 1d are made up of a block outer wall 2 surrounding the outer periphery of the cylinder parts 1a to 1d, and a crankcase 3 extending downward, and the cylinder parts 1a to 1d are connected to the block outer wall 2 by an upper wall 4 and a lower wall 5. A water jacket 6 is connected between the two and allows cooling water to circulate therebetween.

The deformation prevention structure in the cylinder block is located above the center of the cylinder part 1 and approximately from the upper wall 4.
Ribs A are provided at 1/3 height and extend in the radial direction on all sides of each cylinder portion 1a to 1d.
The cylinder parts 1a to 1d are connected to the block outer wall 2.
The cylinder block is connected to adjacent cylinder parts 1a to 1d to increase the rigidity of the cylinder block, thereby reducing deformation caused by mounting the cylinder head.

That is, in a state where the rib A is not provided, when the cylinder head is tightened, the block outer wall 2 is located at an intermediate position in the piston sliding direction of the cylinder parts 1a to 1d (the piston top dead center position and the piston bottom dead center position). The deformation bulges outward so that it is maximum at a position above the center. on the other hand,
The cylinder parts 1a to 1d expand and deform outward in the same manner as the block outer wall 2 at the portions on the block outer wall 2 side so that the cylinder parts 1a to 1d reach a maximum at almost the same position as the block outer wall 2, and as a result, the cylinder parts 1
On the contrary, the portions where a to 1d are adjacent to each other are reduced and deformed inward.

On the other hand, in the case where the rib A is disposed at the position where the deformation is maximum as described above, the opposing block outer wall 2 is
The ribs A are connected via the ribs A to prevent the outward bulging deformation thereof, and also reduce the bulging deformation of the cylinder portions 1a to 1d in the direction of the outer wall 2 of the block by using the rib A as a bulge. The cylinder parts 1a to 1d are connected by the rib A that connects the cylinder parts 1a to 1d.
The purpose is to suppress the inward shrinking deformation of the

However, in the above cylinder block structure, since the opposing block outer walls 2 are connected via the cylindrical cylinder part 1, the tensile strength in the above connection structure is small due to the curvature of the cylinder part 1, and its reinforcing effect is weak. The effect of preventing bulging deformation of the block outer wall 2 is insufficient. In addition, the effect of deformation of the block outer wall 2 acts directly on the cylinder parts 1a to 1d via the rib A, resulting in wavy deformation on the inner peripheral surface of the cylinder part, and the effect of reducing deformation is insufficient. However, it still has various problems.

In view of this point, the present invention provides a cylinder block structure in which deformation of the cylinder portion and outer wall of the block is minimized.

Embodiments of the present invention will be described below with reference to the drawings.

In the cylinder block for a four-cylinder engine shown in FIGS. 4 and 5, 1a to 1d are four cylindrical cylinder parts arranged in series for the first to fourth cylinders, and 2 is a cylinder part 1a. The block outer wall 2 surrounds the outer periphery of the block 2 and is connected to the lower crankcase 3. The block outer wall 2 is formed by side walls 2a, 2b and front and rear walls 2c, 2d. The cylinder portions 1a to 1d and the block outer wall 2 are integrally connected by an upper wall 4 and a lower wall 5 at the upper and lower ends of the cylinder portions 1a to 1d, and cooling is provided between the cylinder portions 1a to 1d and the block outer wall 2. A water jacket 6 is formed in which water circulates.

In the above cylinder block, each cylinder part 1a to 1d is located at a position in the front-rear direction where each cylinder part 1a to 1d is closest to an adjacent cylinder part 1a to 1d.
d are connected by a connecting member 8. Further, the cylinder portions 1a to 1 by the connecting member 8
d At the connecting position of the cylinder parts 1a to 1
Both side walls 2a and 2b of the block outer wall 2 facing each other on both sides of d are connected by a connecting member 9 extending in a direction orthogonal to the side walls 2a and 2b.
Further, the cylinder bore is constructed by mounting a liner 7 on the inner periphery of each of the cylinder portions 1a to 1d.

In this example, the connecting member 8 that connects the adjacent cylinder parts 1a to 1d is the cylinder part 1a.
It is provided over the entire area from the upper wall 4 to the lower wall 5 in the vertical direction of 1d, that is, in the piston sliding direction, and is made of the same material as the cylinder parts 1a to 1d and the block outer wall 2 and is integrally formed during casting. It is formed.

On the other hand, the connecting member 9 that directly connects the both side walls 2a and 2b of the block outer wall 2 is formed in advance from a steel plate or the like and is placed at an intermediate position in the sliding direction of the piston at the time of casting, and is approximately the total height of the cylinder part from the upper wall 4. It is formed by inserting it in the lower 1/3 position. In other words,
This connecting member 9 has a thickness in the piston sliding direction that allows cooling water to flow in the cylinder arrangement direction (front-back direction) on both sides (upper and lower) of the connecting member 9 in the piston sliding direction, and has hook-shaped ends at both ends. The locking portion 1 is provided with locking portions 10, 10 bent to
0 and 10 are cast and embedded in the side walls 2a and 2b of the block outer wall 2, respectively, to connect the side walls 2a and 2b. This connecting member 9 can be used as a member (so-called a support) for supporting the core during casting.

Therefore, according to the cylinder block of this example, the opposite side walls 2a and 2b of the block outer wall 2 are linearly connected via the orthogonal connecting member 9 at a position where the amount of deformation tends to be the largest. As a result, the tensile strength of the connecting structure is large, which effectively prevents and reduces the deformation of the block outer wall 2 (increase in the distance between the side walls 2a and 2b). The bulging deformation toward the 2b side is also suppressed. In addition, the adjacent cylinder portion 1a
~1d are mutually connected by the connecting member 8, thereby preventing an increase in the distance between the cylinder parts, and suppressing inward shrinkage deformation of each cylinder part 1a to 1d by canceling each other out. It is something that

Incidentally, the front and rear end cylinder parts 1a and 1d for the first and fourth cylinders are connected to the front and rear walls 2c of the block outer wall 2,
2d, the deformation of the block outer wall 2 promotes the deformation of the cylinder parts 1a and 1d.
It is preferable not to connect them. That is, connecting the cylinder parts 1a to 1d to the block outer wall 2 in the radial direction as in the prior art shown in FIGS. This is not desirable.

Also, the cooling water is supplied to both side walls 2a of the block outer wall 2,
The cooling water flows freely in the cylinder arrangement direction through the upper and lower sides of the connecting member 9 that connects the 2b, thereby ensuring circulation of cooling water and cooling performance of the cylinder portion.

Since the connecting member 9 is separate from the block outer wall 2, etc., it is possible to reduce the thickness in the cylinder arrangement direction by using a steel plate or the like, thereby reducing the overall length of the cylinder block, that is, making it smaller and lighter. Further, by using the core as a core support member during casting, the production of the cylinder block becomes easier.

Incidentally, although the connecting member 8 that connects adjacent cylinder parts is provided over the entire height of the cylinder part in the above embodiment, the thickness in the piston sliding direction is set to a predetermined thickness by the installation height of the connecting member 9. By providing the cylinder with a thickness (for example, approximately the same thickness as the connecting member 9), the cooling water can flow across the cylinder parts above and below the connecting member that connects the adjacent cylinder parts. It is also possible to improve cooling performance.

Also, the cylinder bores may be formed by the inner peripheral surfaces of the cylinder portions 1a to 1d without providing liners.

Therefore, according to the present invention, the connecting member that connects adjacent cylinder parts and the connecting member that connects the outer walls of the blocks allow the cylinder head to be tightened with a large number of bolts through the gasket to the cylinder block. It is possible to prevent deformation of the cylinder part without interfering with the flow of cooling water in the arrangement direction, and to maintain good roundness and straightness of the inner periphery of the cylinder part. Since it is separate from the cylinder block, the connecting member can be made thinner to shorten the overall length of the block, and the cylinder block can also be manufactured easily.

[Brief explanation of the drawing]

Figures 1 to 3 show conventional examples, with Figure 1 being a longitudinal sectional view of the cylinder block, and Figure 2
The figure is a cross-sectional view taken along the - line of Fig. 1, and Fig. 3 is a cross-sectional view taken along the - line of Fig. 1. Figs. 4 and 5 illustrate embodiments of the present invention; A vertical cross-sectional view of an example cylinder block, FIG.
FIG. 3 is a cross-sectional view taken along the - line in the figure. 1a to 1d...Cylinder part, 2...Block outer wall, 2a, 2b...Side wall, 2c...Front wall, 2d...
...Rear wall, 3...Crankcase, 4...Top wall, 5
... lower wall, 6 ... water jacket, 7 ... liner, 8 ... connection member, 9 ... connection member, 10 ...
...Latching part.

Claims (1)

[Scope of utility model registration request] a cylinder part in which a piston reciprocates;
In a cylinder block for a water-cooled engine that is equipped with a water jacket between the cylinder part and the outer wall of the block that is integrally formed, the adjacent cylinder part and the cylinder part are connected at an intermediate position in the piston sliding direction of the cylinder part. A connecting member is provided that connects the cylinder parts to prevent an increase in the distance between the cylinder parts, and connects the opposing outer walls of the blocks at the position where the cylinder parts are connected, thereby increasing the distance between the outer walls of the blocks. A connecting member that prevents an increase in the distance between the blocks is provided on both sides of the connecting member in the piston sliding direction with a thickness that allows cooling water to flow in the arrangement direction of the cylinder parts, and the connecting member that connects the outer walls of the blocks. The engine is formed separately from the cylinder part and the block outer wall, and has locking parts provided at both ends embedded in the opposing block outer walls to connect the two block outer walls. cylinder block.