JP2000310155A - Cylinder block and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder block for suppressing the deformation of a bore wall and excellent in productivity, and its manufacturing method. SOLUTION: An open-deck cylinder block has a cylindrical bore wall 2, and an engine outer wall 3 provided on the outer part of the wall 2, and is formed of water jackets 41 and 42 between both the walls 2 and 3, and is comprized by providing an opening part 43 on the upper ends of water jackets 41 and 42. The jackets 41 and 42 are tiltedly provided on the right and left part of a reference surface P respectively with the surface P including the axial line L of the wall 2 as the center, and the wall 2 has a thick thickness part 21 having thicker thickness with near to the opening part 43 in accordance with the tilts of the jackets 41 and 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open deck type cylinder block having an opening at the upper end of a water jacket and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 8 to 10, a cylinder block 9 has a bore wall 92 and an engine outer wall 93.
An open deck type is known in which a continuous annular opening 943 is provided at the upper end of a water jacket 94 formed between the water jacket 94. This open deck cylinder block 9 is usually manufactured by casting an aluminum alloy or the like by a die casting method or the like.

In this case, the water jacket 9 is used.
4. The recesses of the combustion chamber 10 and the like are formed by disposing a core such as a jacket type or a bore type in a cavity of a mold (not shown) for performing die casting or the like. Then, as shown in FIG. 9, after the cores such as the jacket mold 961 and the bore mold 962 are arranged at predetermined positions, die casting is performed, and then the jacket mold 961 and the bore mold 962 are connected to the axis of the bore wall 92. Slide along to open the mold.

As a result, the open deck cylinder block 9 is obtained, and the water jacket 94 and the combustion chamber 10 are formed at the positions where the jacket mold 961 and the bore mold 962 are arranged. As shown in FIG. 8, the bore wall 92 formed between the water jacket 94 and the combustion chamber 10 has a cylindrical shape with a substantially constant thickness. The water jacket 94 formed by the jacket mold 961 is connected to the bore wall 9.
In parallel with the second axis, an annular shape surrounding the bore wall 92 is provided.

[0005]

However, the conventional cylinder block has the following problems. That is, the upper end of the bore wall 92 is a free end and has relatively low rigidity. Therefore, as shown in FIG. 10, the upper end of the bore wall 92 may be deformed outward in the radial direction due to, for example, heat or pressure during combustion.

[0006] In a multi-cylinder engine, the above deformation is likely to occur in a portion where the bore walls 92 are not adjacent to each other. For example, when a plurality of bore walls 92 are arranged adjacent to each other in series, and a plane including the axes of all the bore walls 92 is defined as a reference plane Q, as shown in FIG. Easy to spread in the left and right direction by sandwiching. further,
The bore walls 92 located at both ends are likely to spread in the front-rear direction along the reference plane Q.

To solve this problem, as shown in FIG. 11, an insert member 98 is press-fitted or welded into the opening 943 of the cylinder block 9 to form the bore wall 9.
It has been proposed to join the engine outer wall 93 to the engine outer wall 93 to suppress the deformation (Japanese Patent Laid-Open No. 1-100352).
issue). However, it is necessary to perform press-fitting, welding, and the like of the insert member 98 after casting, which causes a problem of low productivity.

If the bore wall 92 is made thicker as a whole to increase the rigidity, unnecessary pressure is applied to the lower end where relatively low pressure is applied during combustion and the deformation is relatively small. Therefore, the yield of the material is reduced. Further, with the increase in the thickness of the bore wall 92 as a whole, shrinkage cavities are likely to be generated in the bore wall 92.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a cylinder block capable of suppressing deformation of a bore wall and having excellent productivity and a method of manufacturing the same. .

[0010]

A first aspect of the present invention has a cylindrical bore wall and an engine outer wall provided outside the bore wall, and a water is provided between the bore wall and the engine outer wall. In an open-deck cylinder block having a jacket formed and an opening provided at an upper end of the water jacket, the water jacket is inclined left and right around a reference plane including the axis of the bore wall. The cylinder block is characterized in that the cylinder wall has a thick wall portion that becomes thicker as it approaches the opening in accordance with the inclination of the water jacket.

It is most remarkable in the present invention that the water jacket is disposed so as to be inclined with respect to the reference plane, and the bore wall is made thicker as described above in accordance with the inclination of the water jacket. That is, a thick portion is provided.

The cylinder block may be applied to a single cylinder engine or a multi-cylinder engine. The water jacket has a portion inclined leftward with respect to the reference plane and a portion inclined rightward. The inclination angle of the water jacket with respect to the reference plane may be the same for the portion inclined leftward and the portion inclined rightward, or may be different.

Next, the operation of the present invention will be described. In the present invention, the thick portion is provided in the bore wall, and the thickness of the water jacket on the upper end side near the opening is positively increased. For this reason, the rigidity of the upper end of the bore wall is significantly higher than in the past. Therefore, for example, even when a relatively high pressure is applied to the upper end of the bore wall at a high temperature during combustion, deformation can be suppressed by the rigidity of the bore wall itself.

Further, as described above, the reinforcement of the upper end of the bore wall can be achieved by improving the rigidity of the bore wall itself by increasing the thickness of the bore wall. Therefore, there is no particular need to join another member to the opening of the water jacket as in the conventional case, and no additional manufacturing process is required. Therefore, the cylinder block of the present invention is excellent in productivity.

Next, as in the second aspect of the present invention, it is preferable that a connection boss connecting the bore wall and the engine outer wall is provided at a position where the opening intersects the reference plane.

In this case, as described above, the rigidity accompanying the thickening of the bore wall not only suppresses the deformation of the bore wall in the left-right direction with the reference surface interposed, but also suppresses the connection boss. The deformation of the bore wall in the front-rear direction along the reference plane can be suppressed by the connection between the bore wall and the engine outer wall. Further, the rigidity of the outer wall of the engine can be increased, so that noise can be reduced.

Further, for example, in a multi-cylinder engine, when a plurality of bore walls are arranged adjacent to each other in series, deformation of the bore walls in the cylinders located at both ends in the front-rear direction is reduced by the bore wall in the cylinder located in the middle. It can be suppressed to the same extent as deformation. Therefore, in particular, burn-in in the cylinders located at both ends can be suppressed.

Next, as in the third aspect of the present invention, the connecting boss has an inverted triangular cross-sectional shape having a base on the opening side, and the apex thereof is formed on the reference surface. Is preferably provided at an acute angle obtained by inclining left and right from the reference plane by an angle smaller than the inclination angle of the water jacket.

In this case, the mold for forming the water jacket (a jacket mold described later) does not have an undercut structure. Therefore, the mold for casting the cylinder block can have a simple structure.

Next, a fourth aspect of the present invention is a method of manufacturing an open deck type cylinder block having a water jacket between a cylindrical bore wall and an engine outer wall provided outside the bore wall. The jacket mold divided by the reference plane including the axis of the bore wall is placed in the cavity of the mold and cast in a state where the jacket mold is inclined left and right with respect to the reference plane, thereby forming the cylinder block. A method of manufacturing a cylinder block, wherein a water jacket having an opening at an upper end is formed.

As the material of the cylinder block, for example, cast iron, aluminum or the like can be used. Examples of the method for casting the cylinder block include a sand casting method and a die casting method.

In manufacturing the cylinder block, first, at the time of mold clamping, the jacket mold divided into the left and right sides by the reference plane is set to the left or right with respect to the reference plane. Place in the cavity. Next, after casting the material (melt) of the cylinder block into the cavity, the material is cooled. Next, when the molds are opened, the left and right jacket molds are slid along the respective inclined directions and pulled out.

As a result, an open deck cylinder block is obtained, and the water jacket is formed at the position where the jacket mold is disposed. At the same time, the bore wall is formed in the portion included in the left and right jackets, and the engine outer wall is formed in the outer portions of the left and right jackets.

In the above manufacturing method, since the jacket mold is divided into right and left by the reference plane, the left and right jacket molds can be slid along different inclination directions. Therefore, the water jacket formed by the jacket mold can be provided so as to be inclined left and right with respect to the reference plane. Therefore, it is possible to provide the bore wall with a thick portion whose thickness increases as approaching the opening in accordance with the inclination of the water jacket.

Therefore, according to the above manufacturing method, the above-mentioned cylinder block can be easily manufactured by casting. Further, after casting, there is no need to perform press-fitting, welding, or the like of other members as in the related art, so that productivity can be improved.

Next, as in the fifth aspect of the present invention, the jacket mold has a cut line inclined at an upper end facing the reference plane at an angle smaller than the inclination angle of the jacket mold with respect to the reference plane. It is preferable to have the notch removed.

In this case, the jacket mold has a cutout at the upper end facing the reference plane, which is deleted by the cutout line. For this reason, at the time of mold clamping, a space having an inverted triangular cross section having a bottom on the opening side of the water jacket is formed between the notch portions of the left and right jackets.

Therefore, at the time of casting, since the gap communicates the inside and the outside of the left and right jacket molds, the bore wall and the engine outer wall are located at the position where the opening intersects the reference plane. And can be connected. Therefore, the above-mentioned connecting boss can be easily formed at the time of casting.

The jacket-type notch is
If it is deleted by a cut line inclined at an angle equal to or greater than the inclination angle of the jacket type with respect to the reference plane,
Since the jacket mold has an undercut structure, the jacket mold cannot be slid along the inclined direction. Therefore, the connecting boss obtained by the above-described manufacturing method has an apex having an apex portion obtained by inclining left and right from the reference surface by an angle smaller than an inclination angle of the water jacket with respect to the reference surface.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A cylinder block and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to FIGS. In this example, a cylinder block applied to an in-line four-cylinder engine is shown. As shown in FIGS. 1 to 4, the cylinder block 1 of this embodiment has a cylindrical bore wall 2 and an engine outer wall 3 provided outside the bore wall 2. Water jackets 41 and 4 between outer wall 3
2 and the water jackets 41, 4
2 is an open-deck cylinder block having an opening 43 at the upper end.

The water jackets 41 and 42 are provided so as to be inclined left and right about a reference plane P including the axis L of the bore wall 2 as a center, and the bore wall 2 is provided with the water jackets 41 and 42. There is a thick portion 21 whose thickness increases as it approaches the opening 43 in accordance with the inclination of 42.

The details will be described below. The four bore walls 2 are arranged adjacent to each other in series with their axes L parallel to each other. As shown in FIG. 1, each of the bore walls 2 has a combustion chamber 10 therein, and a piston (not shown) is arranged in the combustion chamber 10 so as to be able to reciprocate. A cylinder liner 28 is fitted on the inner peripheral surface of the bore wall 2. The inner peripheral surface of each bore wall 2 has a substantially perfect circular cross-sectional shape from the lower end to the upper end, as shown in FIG. It has an elliptical cross-sectional shape swelling in the left-right direction by 21. FIG. 2 shows an AA cross section in FIG.

The engine outer wall 3 is a cylindrical body surrounding the four bore walls 2 as shown in FIGS. The water jackets 41 and 42 are gaps provided between the bore wall 2 and the engine outer wall 3, and are configured so that cooling water for cooling the bore wall 2 can pass through the water jackets 41 and 42. .

The water jackets 41 and 42 are provided symmetrically with respect to the reference plane P as shown in FIG. A water jacket 41 inclined leftward with respect to the reference plane P, and a water jacket 42 inclined rightward.
Are communicated on the reference plane P and are provided in an annular shape surrounding the bore wall 2. The inclination angle α of the water jacket 41 with respect to the reference plane P and the inclination angle β of the water jacket 42 with respect to the reference plane P are both 5
Degrees. The reference plane P in this example includes all the axes L of the four bore walls 2.

The cylinder block 1 is used in a state in which a cylinder head is disposed on an upper surface of the cylinder block via a head gasket, and both are tightened by head bolts to fix the cylinder head.

Next, an outline of a method of manufacturing the cylinder block 1 will be described. As shown in FIGS. 3 and 4, the manufacturing method of this embodiment is an open deck type having water jackets 41 and 42 between a cylindrical bore wall 2 and an engine outer wall 3 provided outside the bore wall 2. Is a method of manufacturing the cylinder block 1 of FIG. The jacket dies 61 and 62 divided by the reference plane P including the axis L (FIG. 1) of the bore wall 2 are inclined left and right with respect to the reference plane P, respectively. The water jackets 41 and 42 having an opening 43 at the upper end of the cylinder block 1 are formed by casting in the cavity.

The details will be described below. In this embodiment, the cylinder block 1 is manufactured by casting an aluminum alloy by a die casting method. The water jacket 41, 42
Is formed by disposing a jacket mold shown below in a cavity of a mold (not shown) for performing die casting.

As shown in FIGS. 3 and 4, the jacket dies 61 and 62 are divided by a reference plane P including the axis L of the bore wall 2 to be obtained, and are centered on the reference plane P. It is configured so that it can be arranged to be inclined to the left and right sides. As shown in FIG. 4, the inclination angle of the jacket mold 61 is different from that of the water jacket 41.
And the inclination angle of the jacket mold 62 is equal to the inclination angle β of the water jacket 42.

The jacket dies 61 and 62 are slightly thicker on the upper end side. The jacket dies 61 and 62 are provided on the inner peripheral surface of the bore wall 2 (the combustion chamber 1).
0) is provided separately from the cylindrical bore mold 63 for forming (0).

In manufacturing the cylinder block 1, as shown in FIG. 3, first, at the time of mold clamping, a jacket mold 61, which is divided into right and left by the reference plane P,
62 are disposed in the cavity of the mold so as to face the reference plane P and to tilt left or right with respect to the reference plane P, respectively. Next, the molten aluminum alloy, which has reached the casting temperature, is pumped into the cavity under high pressure. After the casting, a predetermined cooling process is performed. Next, when the molds are opened, the left and right jacket molds 61, 62 are formed.
Slide along the respective inclination directions and pull out.

Thus, an open deck type cylinder block 1 is obtained. As shown in FIG. 4, the water jackets 41 and 42 are formed at positions where the jacket dies 61 and 62 are arranged. At the same time, the bore wall 2 is formed in a portion included in the left and right jacket dies 61 and 62, and the engine outer wall 3 is formed in an outer portion of the left and right jacket dies 61 and 62.

Next, the operation of this embodiment will be described. In the cylinder block 1 of the present embodiment, as shown in FIG. 1, the thick wall portion 21 is provided in the bore wall 2, and the upper end of the water jackets 41 and 42 near the opening 43 is positively thickened. I have. Therefore, even if the bore wall 2 is not joined to the engine outer wall 3 by an insert member or the like, the rigidity of the upper end of the bore wall 2 is greatly increased as compared with the conventional example. Therefore, even when a relatively high pressure is applied to the upper end of the bore wall 2 at a high temperature during combustion, the deformation can be suppressed by the rigidity of the bore wall 2 itself.

As described above, the upper end of the bore wall 2 can be reinforced by improving the rigidity of the bore wall 2 itself by increasing the thickness of the bore wall 2. Therefore, there is no particular need to join an insert member or the like to the opening 43 of the water jacket 4 as in the conventional example, and no additional manufacturing process is required. Therefore, the cylinder block 1 of this example is also excellent in productivity.

In the manufacturing method of this embodiment, as shown in FIG. 3, the jacket dies 61 and 62 are divided into left and right parts by the reference plane P, so that the left and right jacket dies 61 and 62 are separated from each other. It can be pulled out by sliding along the inclination direction. Therefore, the water jacket 41 formed by the jacket mold 61 is inclined leftward with respect to the reference plane P, and the water jacket 42 formed by the jacket mold 62 is inclined with respect to the reference plane P. It can be provided inclined to the right.

Therefore, the bore wall 2 can be provided with the thick portion 21 whose thickness increases as it approaches the opening 43 in accordance with the inclination of the water jackets 41 and 42. Therefore, according to the manufacturing method, the cylinder block 1 capable of suppressing deformation of the bore wall can be easily manufactured by casting. Also, after casting,
Since there is no need to press-fit or weld the insert member or the like, productivity can be improved.

In this embodiment, as described above, the cylinder block 1 is manufactured by the die casting method. Therefore, productivity can be further improved as compared with the sand casting method. In addition, since there is no need to use a core having a complicated structure, it can be manufactured more easily.

Embodiment 2 As shown in FIGS. 5 to 7, this embodiment employs the bore wall 2 and the engine outer wall 3 at positions intersecting with the reference plane P in the openings 43 of the water jackets 41 and 42. And a connecting boss 5 for connecting the two. As shown in FIG. 5, the connecting boss 5 has an inverted triangular cross-sectional shape having a base on the side of the opening 43, and the apex 51 of the connecting boss 5 is formed by taking the draft into consideration. 41 and 42 are provided at acute angles inclined at angles smaller than the inclination angles α and β. That is, the left hypotenuse angle γ of the apex 51 is smaller than the inclination angle α,
Is smaller than the inclination angle β. Other configurations are the same as those of the first embodiment.

In this embodiment, casting is performed using jacket dies 61 and 62 shown in FIG. The jacket dies 61 and 62 have a notch 6 which is cut at a top end facing the reference plane P by a cut line C inclined at an angle smaller than the inclination angles α and β of the water jackets 41 and 42.
Five.

In this embodiment, the cylinder block 1
Is provided with the connecting boss 5 as shown in FIGS. Therefore, as described above, the rigidity accompanying the thickening of the bore wall 2 not only suppresses the deformation of the bore wall 2 in the left-right direction with the reference plane P interposed therebetween, but also suppresses the bore formed by the connecting boss 5. Due to the connection between the wall 2 and the engine outer wall 3, deformation of the bore wall 2 in the front-rear direction along the reference plane P can also be suppressed. Further, the rigidity of the engine outer wall 3 can be increased, so that noise can be reduced.

Further, the deformation of the bore wall 2 in the cylinders located at both ends of the in-line four cylinders in the front-rear direction can be suppressed to the same degree as the deformation of the bore wall 2 in the cylinder located at the middle. Therefore, in particular, burn-in in the cylinders located at both ends can be suppressed.

As shown in FIG. 5, the apex portion 51 of the connecting boss 5 is provided at an acute angle which is smaller than the inclination angles α and β of the water jackets 41 and 42. Therefore, the jacket dies 61 and 62 do not have an undercut structure. Therefore, the mold for casting the cylinder block 1 can have a simple structure.

In this embodiment, the notch 6
Casting is performed using the jacket dies 61 and 62 having the five. Therefore, at the time of mold clamping, a gap having an inverted triangular cross section having a base on the opening 43 side of the water jacket is formed between the notches 65 of the left and right jacket molds 61 and 62.

Therefore, at the time of casting, since the above-mentioned gaps communicate the inside and outside of the left and right jacket dies 61 and 62, as shown in FIG. At the intersection position, the bore wall 2 and the engine outer wall 3 can be connected. Therefore, the connecting boss 5 that can increase the rigidity of the bore wall and the outer wall of the engine can be easily formed at the time of casting.

The inclination of the cut line C is smaller than the inclination angle of the jacket dies 61 and 62 with respect to the reference plane P. Therefore, the jacket type 6
1, 62 can be pulled out by sliding smoothly along the respective inclination directions. In addition, the same functions and effects as those of the first embodiment can be obtained.

[0055]

As described above, according to the present invention, it is possible to provide a cylinder block capable of suppressing deformation of a bore wall and having excellent productivity and a method of manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a cylinder block according to a first embodiment.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a partially sectional perspective view of a jacket type and a cylinder block in the first embodiment.

FIG. 4 is a cross-sectional view illustrating an arrangement of a jacket type in the first embodiment.

FIG. 5 is a sectional view of a cylinder block according to a second embodiment.

FIG. 6 is a sectional view taken along line BB in FIG. 5;

FIG. 7 is a partial cross-sectional perspective view of a jacket type and a cylinder block in a second embodiment.

FIG. 8 is a partial cross-sectional perspective view of a cylinder block in a conventional example.

FIG. 9 is a cross-sectional view illustrating an arrangement of a jacket type in a conventional example.

FIG. 10 is a partial cross-sectional perspective view illustrating deformation of a bore wall in a conventional example.

FIG. 11 is a partial cross-sectional perspective view of an open deck type cylinder block provided with an insert member in a conventional example.

[Explanation of symbols]

 1. . . 1. cylinder block, . . Bore wall, 21. . . Thick part, 3. . . Engine outer wall, 41, 42. . . Water jacket, 43. . . Opening, 5. . . Connecting boss, 61, 62. . . Jacket type, 65. . . Notch, P. . . Reference plane, α, β. . . Tilt angle,

Claims (5)

[Claims] 1. A water jacket having a cylindrical bore wall and an engine outer wall provided outside the bore wall, wherein a water jacket is formed between the bore wall and the engine outer wall. An open-deck cylinder block having an opening at the upper end thereof, wherein the water jacket is provided to be inclined left and right about a reference plane including the axis of the bore wall, respectively, A cylinder block having a thick portion whose thickness increases as approaching the opening in accordance with the inclination of the water jacket. 2. The cylinder block according to claim 1, wherein a connection boss connecting the bore wall and the engine outer wall is provided at a position of the opening crossing the reference plane. 3. The water jacket according to claim 2, wherein the connecting boss has an inverted triangular cross-sectional shape having a base on the side of the opening, and a vertex of the connecting boss with respect to the reference plane. A cylinder block provided at an acute angle obtained by inclining left and right from the reference plane by an angle smaller than the inclination angle. 4. A method of manufacturing an open deck type cylinder block having a water jacket between a cylindrical bore wall and an engine outer wall provided outside the bore wall, the reference including an axis of the bore wall. A water jacket having an opening at the upper end of the cylinder block by casting and placing the jacket mold divided by the surface in the cavity of the mold in a state in which the jacket mold is inclined left and right with respect to the reference surface, respectively. Forming a cylinder block. 5. The notch according to claim 4, wherein the jacket mold has a notch at an upper end portion facing the reference plane, which is deleted by a cut line inclined at an angle smaller than an inclination angle of the jacket mold with respect to the reference plane. A method for manufacturing a cylinder block, comprising: