JP2005163764A - Cylinder block and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve productivity of a cylinder block and facilitate correspondence to change of piston stroke. <P>SOLUTION: In this cylinder block 10 in which a water jacket 30 is formed around a cylinder 11, the cylinder block 10 is divided into a main body cylinder block 5 constituting a wall face on a cylinder 11 side and an outer peripheral cylinder block 6 surrounding the outer periphery of the main body cylinder block 5 using a section which becomes the water jacket 30 as boundary. Cross section in the direction in which the outer peripheral cylinder block 6 crosses the direction of cylinder extension orthogonally is formed to have an equal cross sectional shape over the whole length of the outer peripheral cylinder block 6 in the direction of cylinder extension. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cylinder block in which a water jacket is formed around a cylinder and a method for manufacturing the same.

In a cylinder block such as a water-cooled gasoline engine or a diesel engine, a water jacket for circulating cooling water is formed around the cylinder. Usually, such a cylinder block is integrally cast, and the water jacket is formed by a water jacket mold disposed in the casting mold (Patent Document 1, etc.).
JP-A-5-296103

  Thus, when forming a water jacket in a cylinder block at the time of casting, it is necessary to make thin the mold part which forms a water jacket in a casting mold. Especially when cooling capacity with cooling water is sufficient and it is not necessary to cool the cylinder more than necessary from the viewpoint of combustibility, or when considering miniaturization and weight reduction of the engine, the water jacket is made extremely narrow. There is a need to.

  For this reason, it is necessary to make the water jacket mold portion extremely thin also in the casting mold. Thus, when a thin part arises in a casting mold, it will become easy to produce casting defects, such as a cast hole. In addition, when the cylinder block is cast, the water jacket mold portion is easily damaged or consumed, and the mold life is shortened. For this reason, there has been a limit to improving productivity.

  On the other hand, in recent years, attempts have been made to improve the efficiency of design and production by sharing parts among different types of engines. Development of a series engine with only the displacement changed while maintaining the basic engine configuration has been made as part of such efforts. However, when manufacturing series engines with only different displacements in this way, even if the bore diameters of the cylinders are the same, if the piston stroke is different, the overall shape of the cylinder block must be changed. It was also necessary to recreate the casting mold. Therefore, there is a demand for the development of a cylinder block that can easily cope with such a change in the specification of the displacement (piston stroke).

  A first object of the present invention is to further improve the productivity of a cylinder block. The second problem of the present invention is to facilitate the response to the piston stroke change.

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, in a cylinder block in which a water jacket is formed around a cylinder, a main body cylinder block that forms a wall surface on the cylinder side with respect to a portion that becomes the water jacket, and the main body cylinder block The cylinder block is divided into an outer cylinder block that surrounds the outer periphery of the outer cylinder block, and a cross section in a direction orthogonal to the cylinder extending direction of the outer cylinder block is an equal cross section over the entire length of the outer cylinder block in the cylinder extending direction. The gist is that it is formed into a shape.

  In the above configuration, the cylinder block is divided into a main body cylinder block that forms a wall surface on the cylinder side, and an outer peripheral cylinder block that surrounds the outer periphery of the main body cylinder block, with a portion serving as a water jacket as a boundary. When these are assembled, a gap is formed between the outer surfaces of the main body cylinder block and the opposed surfaces of the outer cylinder block, and the water jacket is defined by the gap. The water jacket formed in this manner is separately formed with its inner peripheral wall face on the main body cylinder block side and its outer peripheral wall face on the outer cylinder side. The molding is possible without providing a shape or using a core. Such simplification of the mold shape suppresses casting defects such as a cast hole and prolongs the life of the mold, thereby improving the productivity.

  Since the outer cylinder block has a simple shape in which the cross-section in the cylinder extending direction has an equal cross-sectional shape over its entire length, the outer cylinder block can be easily formed. Moreover, by setting it as such a shape, it becomes possible to form an outer periphery cylinder block as an extrusion molded product by either one of a metal and resin as described in Claim 2.

  In such a case, by adjusting the extrusion length at the time of extrusion molding, an outer peripheral cylinder block corresponding to a different displacement engine having the same bore diameter and different piston stroke can be manufactured with a common extrusion mold. It becomes like. For this reason, when manufacturing a series engine having a different displacement common to the bore diameter, it is not necessary to change the molding die at least for the outer cylinder block, and it is possible to easily cope with such a specification change.

  According to a third aspect of the present invention, in a cylinder block in which a water jacket is formed around a cylinder, a main body cylinder block that forms a wall surface on the cylinder side with respect to a portion that becomes the water jacket, The gist is that the cylinder block is divided and formed in an outer cylinder block surrounding the outer periphery of the cylinder, and the outer cylinder block is formed through extrusion molding in which the cylinder extending direction is an extrusion direction.

  In the above configuration, the water jacket is formed separately on its inner peripheral wall surface on the main body cylinder block side and on its outer peripheral wall surface on the outer cylinder block side. The molding can be performed without providing a narrow convex shape or using a core. Such simplification of the mold shape suppresses casting defects such as a cast hole and prolongs the life of the mold, thereby improving the productivity. In addition, by adjusting the extrusion length of the outer cylinder block during extrusion molding, the outer cylinder block corresponding to different displacement engines with the same bore diameter and different piston strokes can be manufactured with a common extrusion mold. Will be able to. Therefore, even when manufacturing series engines with different displacements with the same bore diameter, it is not necessary to change the molding die for at least the outer cylinder block, and it is possible to easily cope with such changes in specifications. Also become.

  According to a fourth aspect of the present invention, there is provided a method of manufacturing a cylinder block having a water jacket formed around a cylinder, wherein a main body cylinder block constituting a wall surface on the cylinder side of the water jacket of the cylinder block is formed. A step of forming an outer peripheral cylinder block surrounding the outer periphery of the main body cylinder block by extrusion molding with a cylinder extending direction as an extruding direction, and the formed outer peripheral cylinder block in the cylinder block, And a step of assembling the formed body cylinder block.

  In the above method, first, the main body cylinder block that forms the wall surface on the cylinder side of the water jacket of the cylinder block and the outer peripheral cylinder block surrounding the outer periphery of the main body cylinder block are formed separately. The formation of the outer cylinder block at this time is performed by extrusion molding in which the cylinder stretching direction is the extrusion direction. In the outer peripheral cylinder block formed in this way, the cross section in the direction orthogonal to the extrusion direction, that is, the direction orthogonal to the cylinder extending direction has an equal cross-sectional shape over the entire length. Then, the cylinder block is manufactured by assembling the outer peripheral cylinder block and the main body cylinder block integrally formed.

  The water jacket of the cylinder block manufactured in this way is separately formed with its inner peripheral wall surface on the main body cylinder block side and its outer peripheral wall surface on the outer cylinder block side. The mold can be formed without providing a narrow convex shape or using a core. Such simplification of the mold shape suppresses casting defects such as a cast hole and prolongs the life of the mold, thereby improving the productivity.

  Further, since the outer cylinder block is formed by extrusion, it can be formed very easily. Moreover, by adjusting the extrusion length at the time of extrusion molding, an outer peripheral cylinder block corresponding to different displacement engines with the same bore diameter and different piston strokes can be manufactured with a common extrusion mold. It also becomes. For this reason, when manufacturing a series engine with a different displacement common to the bore diameter, it is not necessary to change the molding die for at least the outer cylinder block, and it is possible to easily cope with such a specification change.

  When the outer cylinder block is formed by extrusion molding in this way, interference between the outer cylinder block and other parts such as auxiliary equipment attached to the cylinder block or arranged around the cylinder block may occur. . In particular, when a series engine with different displacements with the same bore diameter as described above is manufactured, even if the above engine does not have the above interference, the above interference occurs due to the change in the cylinder block height due to the change of the piston stroke. Sometimes. Further, for example, a mounting hole for a sensor such as a water temperature sensor may be required in the outer cylinder block. In these cases, as described in claim 5, a step of removing the outer periphery of the outer peripheral cylinder block that has been subjected to extrusion molding is further added, and the problematic part is removed by post-processing to eliminate the interference. Alternatively, the sensor mounting hole may be formed by removing a portion where the sensor needs to be mounted.

[Embodiment 1]
A first embodiment in which the present invention is embodied as a cylinder block for a four-cylinder engine will be described below with reference to FIGS.

  FIG. 1 shows a perspective structure of a main body portion of an engine including a cylinder block according to the present embodiment. The main body portion of the engine includes a cylinder block 10, a gasket 7, and a cylinder head 8.

  As shown in the exploded perspective structure in FIG. 2, the main body of the engine is formed by assembling a cylinder head 8 on a cylinder block 10 via a gasket 7. Moreover, in this Embodiment, the cylinder block 10 is made into the division structure of the main body cylinder block 5 and the outer periphery cylinder block 6, and is formed by assembling these together.

  The main body cylinder block 5 is integrally formed by casting an aluminum alloy. The main body cylinder block 5 is provided with four cylindrical cylinders 11 provided at the upper portion of the main body cylinder block 5, a skirt portion 12 provided at the lower portion, and an intermediate portion between the cylinder 11 and the skirt portion 12. The outer wall mounting portion 13 is provided. A plurality of ribs 14 and 15 for reinforcement are formed on the outer surfaces of the skirt portion 12 and the outer wall placement portion 13.

  The upper surface of the outer wall mounting portion 13 formed so as to surround the base portions of the four cylinders 11 is formed on a plane orthogonal to the extending direction of the cylinder 11, and the mounting surface on which the outer cylinder block 6 is mounted. It is set to 16. The mounting surface 16 is formed with a plurality of bolt holes 17 formed with female threads to which a head bolt for assembling the cylinder head 8 is fastened.

  On the other hand, the outer cylinder block 6 is formed in an annular shape surrounding the outer periphery of each cylinder 11 of the main body cylinder block 5. The height L1 of the outer cylinder block 6, that is, its length in the cylinder extending direction, is formed so as to coincide with the protruding height of the cylinder 11 from the mounting surface 16 in the main body cylinder block 5.

  A plurality of ribs 25 extending in the cylinder extending direction are formed on the outer peripheral surface 21 of the outer cylinder block 6. A plurality of bolt insertion holes 24 penetrating in the extending direction of the cylinder 11 are provided on the outer periphery of the outer cylinder block 6. Each bolt insertion hole 24 is formed at a position corresponding to each bolt hole 17 of the main body cylinder block 5, and the head bolt is fastened to the bolt hole 17 through the bolt insertion hole 24 from the cylinder head 8 side. It has become.

  Further, the outer cylinder block 6 is formed with a hole penetrating the outer peripheral side and the inner peripheral side. This hole is a cooling water port 40 used for inflow and outflow of cooling water with respect to a water jacket formed around the cylinder 11 of the cylinder block 10. In addition, the outer cylinder block 6 is provided with a mounting hole for a knock sensor or the like as necessary, similarly to the cooling water port 40.

  The outer peripheral cylinder block 6 configured as described above is formed such that a cross section thereof, that is, a cross section orthogonal to the cylinder extending direction has a substantially equal cross section throughout its height. Such an outer cylinder block 6 is manufactured through the following steps.

  First, a rough material of the outer cylinder block 6 is formed by extrusion molding. The extruder used for this extrusion molding is configured to include an extrusion mold (die) at one end, a container into which a material such as an aluminum alloy is inserted, and a ram that pressurizes the material in the container. ing. A mold hole (die hole) having the same shape as the cross section of the outer cylinder block 6 is formed in the extrusion mold.

  In such an extruder, the raw material in the container is pressed by the ram and extruded through the mold hole, whereby the coarse material of the outer cylinder block 6 having the same shape as the mold hole is formed. Then, the extruded rough material is cut at a required length (height L1), and the cooling water port 40 and the like are formed by removal processing, or the top surface and the bottom surface are subjected to finishing processing. The outer cylinder block 6 is manufactured.

  On the other hand, the main body cylinder block 5 is integrally formed by casting as described above. Then, the cylinder block 10 is formed as shown in FIG. 3 by placing the outer cylinder block 6 manufactured as described above on the placing surface 16 of the cast main body cylinder block 5. At this time, a gap is formed between the opposed surfaces of the outer peripheral surface 11 a of the cylinder 11 and the inner peripheral surface 20 of the outer cylinder block 6 in the main body cylinder block 5, and the water jacket 30 is partitioned around the cylinder 11 by the gap. Is done.

  The cylinder head 8 is placed on the upper surface of the cylinder block 10 manufactured as described above via the gasket 7. In this state, the cylinder block 10 and the cylinder head 8 are fastened and fixed by a head bolt to form a main body portion of the engine. At this time, the head bolt is fastened to the bolt hole 17 of the main body cylinder block 5 through the bolt insertion hole 24 of the outer cylinder block 6 from the cylinder head 8 side. Accordingly, the outer cylinder block 6 is fastened and fixed by receiving a pressing force from the bottom surface of the cylinder head 8 and the mounting surface 16 of the main body cylinder block 5.

  In such a cylinder block 10 of the present embodiment, the inner peripheral wall surface of the water jacket 30 is formed separately on the main body cylinder block 5 side, and the outer peripheral wall surface thereof is formed separately on the outer cylinder block 6 side. It has become. Therefore, the cylinder block 10 having the water jacket 30 around the cylinder 11 can be manufactured without using a complicated casting mold in which a narrow convex shape or a core for forming the water jacket is provided and complicated. Therefore, the problems at the time of integrally casting a cylinder block having a water jacket, such as casting defects such as the above-mentioned casting hole and a reduction in mold life, can be suitably avoided.

  Moreover, in the present embodiment, the outer peripheral cylinder block 6 is manufactured through extrusion as a simple shape having a substantially equal cross-sectional shape, so that the production efficiency is improved as compared with the case of casting. It is also.

  If the cylinder block 10 is configured as described above, it is possible to relatively easily produce engines with different displacements having the same inner diameter of the cylinder 11, that is, the bore diameter and different piston strokes. Become.

  When the cylinder block 10 shown by a solid line in FIG. 4 corresponds to an engine having the same bore diameter and a larger displacement, that is, an extended piston stroke, the cylinder length is indicated by a two-dot chain line in FIG. Need to be extended as shown. Such extension of the cylinder length can be performed by increasing both the protruding height of the cylinder 11 from the mounting surface 16 of the main body cylinder block 5 and the height of the outer cylinder block 6. In the following description, the height of the outer cylinder block 6 of the engine with the shorter piston stroke as the base is “L1”, and the height of the outer cylinder block 6 ′ corresponding to the engine with the longer piston stroke is “L2”. To do.

  Even if the outer cylinder block 6 ′ has a height L2 corresponding to the extension of the piston stroke as shown in FIG. 5 (a), the height L1 corresponding to the base engine as shown in FIG. 5 (b). The outer peripheral cylinder block 6 can have the same cross-sectional shape, that is, the cross-sectional shape orthogonal to the cylinder extending direction. That is, the piston stroke can be extended without changing anything other than the height. The outer peripheral cylinder blocks 6 and 6 'having only different heights can be manufactured by adjusting the extrusion length at the time of extrusion without changing the extrusion mold. That is, at the time of the extrusion molding, if the extrusion length is increased and the cutting is performed so that the height of the coarse material, that is, the length of the coarse material in the extrusion direction becomes the above-mentioned “L2”, the outer peripheral cylinder having the height L2 The block 6 ′ is manufactured using the same extrusion mold as the outer cylinder block 6 having the height L1.

  As described above, in the cylinder block 10 of the present embodiment including the outer cylinder block 6 formed through the extrusion molding as described above, at least the outer cylinder block 6 has a cylinder length without changing the mold for extrusion molding. It can respond to the change of. In addition, the main body cylinder block 5 can cope with the change of the cylinder length by changing the shape of the cylinder 11 by simply changing the protruding height of the cylinder 11 from the mounting surface 16.

According to the first embodiment described above, the following effects can be obtained.
(A) In the present embodiment, the cylinder block 10 is separated from the portion that becomes the water jacket 30 by the main body cylinder block 5 that forms the wall surface on the cylinder 11 side, and the outer peripheral cylinder that surrounds the outer periphery of the main body cylinder block 5 It is divided into blocks 6. Therefore, problems such as the occurrence of casting defects such as a casting hole and shortening of the mold life when the entire cylinder block is integrally cast can be suitably avoided. Moreover, the outer cylinder block 6 has an equal cross-sectional shape in the extending direction of the cylinder 11 over its entire length, and can be easily manufactured by extrusion. Therefore, the productivity of the cylinder block 10 having the water jacket 30 on the outer periphery of the cylinder 11 can be improved.

  (B) The height of the outer cylinder block 6 can be easily changed through adjustment of the extrusion length during extrusion molding. Therefore, even when manufacturing series engines with different bores with the same bore diameter, at least the outer cylinder block 6 can be manufactured without changing the mold for extrusion molding, and it is easy to respond to such specification changes. Can be done.

[Embodiment 2]
Hereinafter, the second embodiment of the present invention will be described focusing on differences from the first embodiment.
In the outer peripheral cylinder block 6 of the first embodiment, the bolt insertion holes 24 through which the head bolts are inserted and the outer peripheral ribs 25 are formed at the time of extrusion molding. In the second embodiment, the bolt insertion holes, ribs, and the like are formed by removal processing after extrusion of the coarse material, similarly to the cooling water port 40 of the outer cylinder block 6 in the first embodiment. .

  FIG. 6B shows the outer peripheral cylinder block 106 of the present embodiment. As shown in the figure, the outer peripheral cylinder block 106 of the present embodiment, like the outer peripheral cylinder block 6 of the first embodiment, surrounds the cylinder of the cylinder block and becomes the outer peripheral wall of the water jacket. It is formed in an annular shape having a surface 120. A plurality of bolt insertion holes 124 through which the head bolts are inserted are formed around the inner peripheral surface 120.

  On the other hand, on the outer peripheral surface of the outer cylinder block 106, in addition to the rib 125 extending in the cylinder extending direction, a rib 126 extending in a direction orthogonal thereto is also formed. Further, a plurality of through-holes communicating the inner peripheral surface 120 and the outer peripheral surface are formed on the side surface of the outer cylinder block 106, which are sensor mounting holes for mounting sensors such as a knock sensor and a water temperature sensor. 140 and a heater mounting hole 141 for mounting a block heater for heating the cooling water in the water jacket.

Such an outer cylinder block 106 is manufactured as follows.
First, a rough material 106a of the outer cylinder block 106 as shown in FIG. 6A is formed by extrusion molding. The extrusion of the coarse material 106a is performed by forming a die hole having the same shape as a cross section in a direction perpendicular to the height direction, with the height direction, that is, the direction in which the cylinder is stretched, taken as the material extrusion direction. This is performed using the extruded mold.

  The coarse material 106a formed in this way is formed in an annular shape having an inner peripheral surface 120 surrounding the outer periphery of the cylinder, and the cross section in the direction perpendicular to the height direction covers the entire length in the height direction, etc. It has a cross-sectional shape. On the other hand, the outer peripheral surface 121 of the coarse material 106a is formed as a smooth surface without unevenness. At this time, the ribs 125, 126, the sensor mounting hole 140, the heater mounting hole 141, etc. are not formed. Yes. Further, the bolt insertion hole 124 is not formed in the coarse material 106a at this time.

  Thus, after the said rough | crude material 106a is formed by extrusion molding, the removal process is given to the outer peripheral surface 121, and the said ribs 125 and 126 are formed. The bolt insertion hole 124, the sensor mounting hole 140, and the heater mounting hole 141 are also formed through removal processing.

  As described above, the outer cylinder block 106 as described above is manufactured. And the cylinder block is formed by mounting the outer peripheral cylinder block 106 on the mounting surface 16 of the main body cylinder block 5 of the first embodiment.

  Also in this embodiment, since the cylinder block is divided and formed on the boundary of the water jacket formed around the cylinder, the cylinder block is integrally cast to generate casting defects and shorten the casting mold life. The problem can be avoided and the productivity can be improved. Further, since the outer cylinder block 106 is formed through extrusion molding in which the cylinder extending direction is the extrusion direction, it is possible to easily manufacture a series engine having different bores having the same bore diameter and different piston strokes. .

  Also, by forming the ribs and the like by removal after extrusion, the shape that can be formed is limited to a shape with a constant cross section, and the outer shape that cannot be formed by extrusion, for example, extends in a direction perpendicular to the cylinder extending direction. The outer cylinder block 106 can be formed in an outer shape having the ribs 126 and the like.

[Other embodiments]
Each of the above embodiments can be implemented with the following modifications.
-The shape of the outer cylinder block may be appropriately changed as long as it can be dealt with by changing the shape of the mold hole for extrusion and changing the removal processing mode after extrusion. In short, as long as the outer peripheral cylinder block is formed as an extrusion-molded product with the cylinder extending direction as the extrusion direction, the same effects as those in the above-described embodiment can be obtained.

  If the outer peripheral cylinder block has a completely constant cross-sectional shape, that is, if the cross-section in the direction perpendicular to the cylinder extending direction is completely the same cross-sectional shape over its entire length, without performing removal processing, The outer cylinder block can be manufactured only by extrusion.

  In each of the above embodiments, the outer cylinder blocks 6 and 106 are made of an aluminum alloy extruded product, but may be made of an extruded product of other materials such as a resin or a resin composite material.

  In the above embodiment, the main body cylinder block 5 is integrally formed by casting with an aluminum alloy, but the material and manufacturing method are not limited to this, and may be arbitrarily changed. Further, the shape of the main body cylinder block may be appropriately changed as long as it forms a wall surface on the cylinder side with respect to a portion serving as a water jacket formed around the cylinder.

The perspective view which shows the perspective structure of the main-body part of the engine by which the cylinder block which concerns on Embodiment 1 of this invention is employ | adopted. The perspective view which shows the decomposition | disassembly structure of the main-body part of the same engine. The perspective view which shows the decomposition | disassembly structure of the cylinder block of the embodiment. Sectional drawing which shows the cross-section of a cylinder block. The figure which shows together the perspective structure of the outer periphery cylinder block for (a) large displacement engines, and (b) the outer periphery cylinder block for small displacement engines. The outer cylinder block concerning Embodiment 2 of the present invention is a figure which shows together the perspective structure of (a) the material, and (b) the finished product.

Explanation of symbols

  5 ... Main body cylinder block, 6, 106 ... Outer cylinder block, 10 ... Cylinder block, 11 ... Cylinder, 30 ... Water jacket.

Claims (5)

In the cylinder block where a water jacket is formed around the cylinder,
With the portion serving as the water jacket as a boundary, the cylinder block is divided into a main body cylinder block constituting the cylinder side wall surface and an outer peripheral cylinder block surrounding the outer periphery of the main body cylinder block, and
A cylinder block characterized in that a cross section in a direction orthogonal to a cylinder extending direction of the outer cylinder block is formed to have an equal cross-sectional shape over the entire length of the outer cylinder block in the cylinder extending direction.   The cylinder block according to claim 1, wherein the outer cylinder block is formed as an extrusion-molded product made of one of metal and resin. In the cylinder block where a water jacket is formed around the cylinder,
With the portion serving as the water jacket as a boundary, the cylinder block is divided into a main body cylinder block constituting the cylinder side wall surface and an outer peripheral cylinder block surrounding the outer periphery of the main body cylinder block, and
The cylinder block, wherein the outer cylinder block is formed through extrusion molding in which a cylinder extending direction is an extrusion direction. A method of manufacturing a cylinder block having a water jacket formed around a cylinder,
Forming a main body cylinder block that constitutes a wall surface closer to the cylinder than the water jacket of the cylinder block;
In the cylinder block, an outer peripheral cylinder block surrounding the outer periphery of the main body cylinder block is formed by extrusion molding with a cylinder extending direction as an extrusion direction; and
Assembling the formed outer cylinder block to the formed main body cylinder block;
A method for manufacturing a cylinder block, comprising:   5. The method of manufacturing a cylinder block according to claim 4, further comprising a step of removing the outer periphery of the extruded outer cylinder block.

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