JP2001289113A - Aluminum cylinder block for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum cylinder block for an engine, preventing the fatigue breakage of female screw portions to which bolts are threaded in fixing a cylinder head and a crank cap to the cylinder block and avoiding the inconvenience of impossible disassembly of the cylinder head and the crank cap in units during maintenance. SOLUTION: A high strength bolt-female screw member 8, formed stronger than an aluminum material by casting, is embedded in a central portion of the cylinder block 3. The high strength bolt-female screw member 8 has a plurality of high strength bolt-female screw member bodies 8a and connection members 8b for mutually connecting them. The upper and lower parts of the high strength bolt-female screw member bodies 8a are provided with screw holes, serving as head bolt female portions 8c to which head bolts 5 are threaded and as crank cap bolt female portions 8d to which crank cap bolt 6 are threaded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum cylinder block of an engine.

[0002]

2. Description of the Related Art In recent years, there has been a tendency to use an aluminum cylinder block in an engine of an internal combustion engine in order to reduce the weight.

However, when the cylinder block is simply formed of aluminum, due to its strength, a bolt for fixing the cylinder head and the crank cap to the cylinder block is screwed into a female screw portion formed in the cylinder block. Even so, there is a case where the impact caused by the explosion of the fuel may cause a problem that the female bolt portion of the bolt causes fatigue failure or the like. It is also prominent in diesel engines because diesel engines have higher compression ratios than gasoline engines, and therefore have a greater impact on fuel explosions.

[0004] Therefore, it has been proposed to use a high-strength member having a female bolt portion to prevent fatigue failure of the female bolt portion. For example, such an engine is described in Japanese Utility Model Publication No. 63-34345.

The engine described in Japanese Utility Model Laid-Open Publication No. 63-34345 discloses a high-strength member having a female bolt portion incorporated in a crank cap. Then, a bolt reaching from the cylinder head to the crank cap is inserted from above the cylinder head, and a tip end of the bolt is screwed into the crank cap, whereby the cylinder head, the cylinder block and the crank cap are fastened together. .

[0006]

However, when the cylinder head, the cylinder block and the crank cap are fastened together by bolts, the engine described in Japanese Utility Model Laid-Open Publication No. The assembly cannot be performed until all the cylinder blocks and the crank caps are completed, and there is a problem that the conventional production line must be changed.

Further, when repairing, all of the cylinder head, cylinder block, and crank cap must be disassembled, and only one of the cylinder head and crank cap cannot be removed. This caused inconvenience during maintenance.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a method of, for example, fatigue fracture of a female screw portion for screwing a bolt for fastening a cylinder head, a crank cap, or the like to a cylinder block. An object of the present invention is to provide an aluminum cylinder block of an engine that can prevent the occurrence of inconvenience and does not cause inconvenience in maintenance.

[0009]

According to a first aspect of the present invention, in an aluminum cylinder block of an engine to which a cylinder head, a crank cap, and the like are fixed by bolts, at least one of a female screw portion for screwing the bolts is used. The gist of the present invention is that it is formed by integrating a high-strength bolt female screw member.

According to a second aspect of the present invention, in the aluminum cylinder block of the engine according to the first aspect, a head bolt screw portion and a crank cap screw portion are formed on the high-strength bolt female screw member. That was the gist.

According to a third aspect of the invention, in the aluminum cylinder block of the engine according to the first or second aspect, the high-strength bolt female screw member is connected by a connecting member. And

According to a fourth aspect of the present invention, in the aluminum cylinder block of the engine according to the first to third aspects, the bolt female screw high-strength member is located at a position corresponding to a bearing of a cylinder block journal. The gist was that it was built-in.

According to a fifth aspect of the present invention, in the aluminum cylinder block for an engine according to the fourth aspect, the bolt female screw high strength member is integrally connected in a ladder shape by a connecting member. And

(Operation) According to the first aspect of the present invention,
The cylinder head or the crank cap is fixed to the aluminum cylinder block by bolts, and at least one of the bolts is screwed to a female bolt high-strength member integrated with the aluminum cylinder block.

According to the second aspect of the present invention, the high-strength bolt female screw member is pulled upward by tightening the head bolt, and is pulled downward by tightening the crank cap bolt.

According to the third aspect of the present invention, when a bolt is screwed into the female bolt high-strength member, the force with which the female bolt high-strength member is pulled by the bolt is the bolt. Not only does it hang on the female thread high strength member body, but it is also distributed on the connecting portion.

According to the fourth aspect of the present invention, the bolt internal thread high-strength member having higher rigidity than aluminum is integrated at a position corresponding to the bearing of the cylinder block journal, so that the cylinder block journal has The rigidity of the position corresponding to the bearing portion is generally close to the rigidity of the crank cap having higher rigidity than the aluminum material.

According to the fifth aspect of the invention, when casting the aluminum cylinder block, the positioning for incorporating the high-strength bolt female screw member may be performed at one location.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a first embodiment in which an aluminum cylinder block of the present invention is embodied in an engine.
An embodiment will be described with reference to FIGS.

FIG. 1 is a sectional view of a main part of a main part of the engine 1 according to the present invention.

As shown in FIG. 1, the engine 1 has a cylinder head 2, an aluminum cylinder block (hereinafter simply referred to as a cylinder block) 3 and a crank cap 4.

The cylinder head 2 is fixed to an upper part of the cylinder block. In the cylinder head 2 and the cylinder block 3, a head bolt hole 5a for passing the head bolt 5 is formed so as to reach from the upper end of the cylinder head 2 to the center of the cylinder block 3. Cylinder block 3 from above cylinder head 2
The cylinder head 2 is fixed to the cylinder block 3 by a head bolt 5 reaching the center of the cylinder block 3.

A crank cap 4 is disposed below the cylinder block 3. The crank cap 4 and the cylinder block 3 include a crank cap bolt 6
A crank cap bolt hole 6 a through which the cylinder cap 3 passes is formed so as to reach the center of the cylinder block 3 from the lower end of the crank cap 4. The crank cap 4 is fixed to the cylinder block 3 by a crank cap bolt 6 reaching from the lower portion of the crank cap 4 to the center of the cylinder block 3.

The lower portion of the cylinder block 3 is a cylinder journal 3a. A through hole 7 is formed so as to extend over the cylinder block journal portion 3a and the upper portion of the crank cap 4, and the through hole 7 supports a crankshaft (not shown). Since the crankshaft arranged in the through hole 7 transmits a large force, a considerable amount of force is also applied to the crankcap 4. Therefore, it is necessary to increase the rigidity of the crankcap. .

In the center of the cylinder block 3, a high-strength bolt female thread member 8 is embedded.

The bolt female screw high strength member 8 is formed of cast iron having higher strength than aluminum. As shown in FIG. 2, the bolt female screw high-strength member 8 includes a plurality of (eight in the figure) bolt female screw high-strength members 8 a formed in a columnar shape and arranged in two rows of four linearly. The two bolt female screw high strength member main bodies 8a that are adjacent to each other in the row direction or adjacent to the same row direction and the vertical direction, respectively,
As a result, the eight bolt female screw high-strength member main bodies 8a are integrally formed in a ladder shape.

Screw holes are formed in the upper and lower portions of the bolt female screw high strength member body 8a of the bolt female screw high strength member 8, respectively. 8d. The female thread 8c for the head bolt and the female thread 8d for the crank cap bolt are respectively connected to the head bolt 5
And a male screw formed at the tip of the crank cap bolt 6.

In FIG. 2, inside each of the three square rooms formed by being surrounded by the connecting member 8d of the high-strength bolt female screw member 8 spread in the cylinder block 3, each room is indicated by a dashed line. Is located one cylinder 9.

The outline of the method for manufacturing the cylinder block 3 will be described below.

The cylinder block 3 is formed by casting. In the mold of the cylinder block 3, the bolt female screw high-strength member 8 is arranged in advance, and a core is arranged at a position corresponding to the bolt holes 5a, 6a. By pouring molten aluminum into the mold, the cylinder block 3 in which the high-strength female screw member 8 is integrated is formed.

When the cylinder head 2 is to be removed, the screw between the head bolt 5 and the female bolt high-strength member 8 is removed, and the cylinder head 2 is removed. When the crank cap 4 is to be removed, the screw between the crank cap bolt 6 and the female bolt high-strength member 8 is removed, and the crank cap 4 is removed.

Next, the features of the aluminum cylinder block 3 configured as described above will be described below.

(1) A bolt female thread high strength member 8 formed of cast iron having higher strength than aluminum material is built in the center of the cylinder block 3 and integrated to form a head bolt 5
And the crank cap bolt 6 are screwed into the female bolt high-strength member 8, so that the cylinder head 2 is urged upward by the impact of the fuel explosion in the cylinder.
Even if the head bolt 5 is pulled upward, the head bolt 5
It is possible to prevent the head bolt internal thread 8c screwed with the tip of the head bolt from being fractured by fatigue. Similarly, even if the crank cap 4 is pulled downward by the impact transmitted from the crankshaft, the female threaded portion 8d of the crank cap bolt to which the tip of the crank cap bolt 6 is screwed is broken by fatigue. Can be prevented.

When the engine 1 is disassembled for repair or the like, the cylinder head 2 is fastened to the cylinder block 3 by the head bolt 5 and the crank cap 4 is fastened to the cylinder block 3 by the crank cap bolt 6. , Cylinder head 2
Alternatively, only one of the crank caps 4 can be removed.

(2) A female head portion 8c for a head bolt is formed on the upper portion of the main body 8a of the female screw high-strength member 8 of the female bolt high-strength member, and a female screw portion 8d for the crank cap bolt is formed on the lower portion thereof. As a result, the female bolt high-strength member 8 is pulled upward by the head bolt 5 and pulled downward by the crank cap bolt 6, and the forces acting in opposite directions cancel each other. Therefore, since the bolt female screw high-strength member 8 is not strongly stretched in one direction, the aluminum material of the cylinder block 3 around the bolt female screw high-strength member 8 can be prevented from being deformed.

(3) Since the female bolt high-strength member 8a of the female bolt high-strength member 8 is connected in a ladder shape by the connecting member 8b, the female bolt high-strength member body 8a of the female bolt high-strength member 8 is connected. The force that is pulled by the head bolt 5 and the crank cap bolt 6 is applied not only to the bolt female screw high-strength member body 8a but also to the connecting member 8b.
Is also distributed. Therefore, the force applied to the aluminum material of the cylinder block 3 around the bolt female screw high-strength member 8 is reduced, and the deformation of the aluminum material around the bolt female screw high-strength member 3 can be prevented.

Further, when the high-strength bolt female member 8 is embedded in the cylinder block 3 with the casting of the cylinder block 3, the positioning of the high-strength bolt female member 8 can be performed in one place. Becomes easier.

(Second Embodiment) Next, a second embodiment in which an aluminum cylinder block of the present invention is applied to an engine will be described with reference to FIGS. The components having the same functions as in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 3 is a sectional view showing a main part of the engine 20 according to the present invention.

As shown in FIG. 3, in the engine 20, a high-strength bolt female thread member 22 is embedded in a cylinder block journal portion 21a below the cylinder block 21 and integrated therewith.

The bolt female screw high-strength member 22 is made of cast iron having higher strength than aluminum. As shown in FIG. 4, the bolt female screw high-strength member 22 includes a pair of bolt female screw high-strength member main bodies 22a formed in a columnar shape.
And an arch-shaped connecting member 22b for connecting the female bolt high-strength member main bodies 22a to each other. The semicircular recess 22e formed below the connecting member 22b forms the upper part of the crankshaft through-hole 7 shown in FIG.

The bolt female screw high-strength member 22 is incorporated in the cylinder block 3 in a state where the concave portion 22e is not formed in the bolt female screw high-strength member 22. Then, a through hole for the crankshaft is formed with the crank cap 4 fixed to the cylinder block 21. By doing so, the concave portion 22e is also formed in the high-strength member 22 for the female screw.

Screw holes are formed in the upper and lower portions of the bolt female screw high strength member main body 22a to form a female screw portion 22c for a head bolt and a female screw portion 22d for a crank cap bolt, respectively. Is the same for the female screw portion 8c for the head bolt and the female screw portion 8d for the crank cap in the first embodiment.

Next, the features of the aluminum cylinder block 21 configured as described above will be described below.

(1) Cylinder block journal section 21
Since the bolt female screw high-strength member 22 having a higher rigidity than aluminum is built in the inside of a, the rigidity of the cylinder block journal portion 21a is generally closer to the rigidity of the crank cap 4 which is generally higher in rigidity than aluminum. Therefore, when the crankshaft 4 is simultaneously formed on the cylinder block journal 21a and the crank cap 4 with the crank cap 4 mounted on the cylinder block 21, the cylinder block journal 21a
If the rigidity of the cylinder block journal 21a is lower than that of the crank cap 4, it is difficult to form the crankshaft through-hole 7 in the cylinder block journal 21a. If this is the case, it will be easy to accurately form the through hole 7 for the crankshaft.

The high-strength bolt female thread member is not necessarily required to be built in, and may be integrated in a state where the surface is mostly exposed.

(Third Embodiment) Next, a third embodiment in which the aluminum cylinder block of the present invention is applied to an engine will be described with reference to FIG. The components having the same functions as in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 5 is a sectional view of a main part of the engine 30.

As shown in FIG. 5, a high-strength bolt female member 32 incorporated in the center of the cylinder block 31 of the engine 30 is obtained by removing the connecting member 8b from the high-strength bolt female member 8 in the first embodiment. And corresponds to the bolt female screw high strength member main body 8a.

Screw holes are formed in the upper and lower portions of the bolt female screw high-strength member 32 to form a head bolt female screw portion 32c and a crank cap female screw portion 32d, respectively. It is the same as the female thread 8c for the head bolt and the female thread 8d for the crank cap bolt in the first embodiment.

Next, the features of the aluminum cylinder block 31 configured as described above will be described below.

(1) Since the connecting member 8b is removed, the restriction when the high-strength bolt female thread member 32 is arranged in the cylinder block 31 is reduced, and the degree of freedom in arrangement is increased.

(Fourth Embodiment) Next, a fourth embodiment in which an aluminum cylinder block of the present invention is applied to an engine will be described with reference to FIG. The components having the same functions as in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 6 is a sectional view of a main part of the engine 40.

As shown in FIG. 6, an upper bolt female screw high-strength member 42 and a lower bolt female screw high-strength member 43 built in the center of a cylinder block 41 of the engine 40.
Is a bolt female screw high strength member 32 according to the third embodiment.
Is divided into upper and lower parts.

A screw hole is formed in the upper part of the upper bolt female screw high strength member 42, and the screw hole is a female screw portion 42c for a head bolt. It is the same as the female screw portion 8c.
A screw hole is formed in the lower part of the lower bolt female screw high-strength member 43, and the screw hole serves as a female screw portion 42d for a crank cap bolt. It is the same as the female screw part 8d for bolts.

Next, the features of the aluminum cylinder block 41 configured as described above will be described below.

(1) Since the upper bolt female screw high-strength member 42 and the lower bolt female screw high-strength member 43 are divided, the upper bolt female screw high-strength member 42 and the lower bolt female screw high-strength member 43 are divided. Is reduced in disposing in the cylinder block 41, and the degree of freedom in arrangement increases.

(Fifth Embodiment) Next, a fifth embodiment in which the aluminum cylinder block of the present invention is applied to an engine will be described with reference to FIG. The components having the same functions as those of the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 7 is a sectional view of a main part of the engine 50.

As shown in FIG. 7, a hollow portion 52 is formed in the center of a cylinder block 51 of the engine 50. In the hollow part 52, the head bolt 5 reaching from the upper part of the cylinder head 2 to the central part of the cylinder block 51
Is fixed by a nut 53 to fix the cylinder head 2 to the cylinder block 51.

A high-strength bolt female thread member 54 is incorporated in the cylinder block journal portion 51a below the cylinder block 51. Bolt female thread high strength member 54
Is a bolt female screw high strength member 22 according to the second embodiment.
, The head bolt female screw portion 22c is omitted, and a pair of bolt female screw high-strength member main bodies 54a formed in a columnar shape;
a are connected to each other by an arch-shaped connecting member 54b. A female screw portion 54d for a crank cap bolt is formed at a lower portion of the bolt female screw high-strength member main body 54a, and a distal end portion of the crank cap bolt 6 is screwed.

Next, the features of the aluminum cylinder block 51 configured as described above will be described below.

(1) Since it is not necessary to extend the tip of the head bolt 5 to the cylinder block journal 51a, design flexibility is improved.

The embodiment of the present invention is not limited to the above embodiment, but may be implemented as follows.

In the first to fifth embodiments, the high-strength members 8, 22, 32, 42, 4
The cast irons 3 and 54 are made of cast iron, but they only need to have a strength that does not hinder practical use, and cast iron is an example of the high strength members 8, 22, 32, 42, and 4 of the female screw.
3, 54 may be formed of steel, a high-strength MMC material (metal-based composite material), or the like.

[0067]

According to the first aspect of the present invention, at least one of a head bolt for fixing the cylinder head to the cylinder block and a crank cap bolt for fixing the crank cap to the cylinder block is fatigued by a female screw portion. Breakage can be prevented, and by removing one of the head bolt and the crank cap bolt, only one of the cylinder head and the crank cap can be removed.

In addition, according to the second aspect of the present invention,
Since the force for pulling the bolted high-strength member upwards cancels each other, the bolted high-strength member is strongly pulled upward or downward, and the aluminum material around the bolted high-strength member. Can be prevented from being deformed.

In addition, according to the third aspect of the present invention,
It is possible to prevent deformation of the aluminum material around the bolt female screw high strength member.

In addition, according to the fourth aspect of the present invention,
When a crankshaft through-hole is simultaneously formed in the cylinder block journal and the crank cap with the crank cap mounted on the cylinder block, the rigidity at the position corresponding to the bearing of the cylinder block journal is lower than that of the crank cap. However, according to the present invention, the rigidity of the position corresponding to the bearing of the cylinder block journal is close to the rigidity of the crank cap. It is easy to accurately form the through hole.

In addition, according to the fifth aspect of the present invention,
The manufacturing process becomes easier.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part for describing a first embodiment.

FIG. 2 is a perspective view of the same high-strength bolt female screw member 8;

FIG. 3 is an essential part cross-sectional view for explaining a second embodiment.

FIG. 4 is a perspective view of a bolt female screw high-strength member 22;

FIG. 5 is a sectional view of an essential part for describing a third embodiment.

FIG. 6 is an essential part cross-sectional view for explaining a fourth embodiment;

FIG. 7 is an essential part cross-sectional view for explaining a fifth embodiment;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Cylinder head, 3 ... Aluminum cylinder block, 4 ... Crank cap, 5 ... Head bolt, 6 ... Crank cap bolt, 8 ... Bolt female thread high strength member, 8a ... Bolt female thread high strength member main body , 8b ...
Connecting member

Claims (5)

[Claims] In an aluminum cylinder block of an engine to which a cylinder head, a crank cap, and the like are fixed by bolts, at least one of a female screw portion to which the bolt is screwed is formed by integrating a bolt female screw high-strength member. Aluminum cylinder block of engine formed. 2. The aluminum cylinder block for an engine according to claim 1, wherein the high-strength bolt female member has a screw portion for a head bolt and a screw portion for a crank cap. 3. An aluminum cylinder block for an engine according to claim 1, wherein said high-strength bolt female screw member is connected by a connecting member. 4. An aluminum cylinder block for an engine according to claim 1, wherein said bolt female screw high-strength member is incorporated at a position corresponding to a bearing of a cylinder block journal. block. 5. The aluminum cylinder block for an engine according to claim 4, wherein the high-strength bolt female thread member is integrally connected in a ladder shape by a connecting member.