JP4036200B2 - Cylinder block structure of multi-cylinder engine and manufacturing method thereof - Google Patents

Description

  The present invention relates to a cylinder block structure of a multi-cylinder engine and a manufacturing method thereof.

  Conventionally, in a water-cooled cylinder block of an in-line multi-cylinder engine, a closed deck type in which a top deck is closed and a siamese type cylinder block in which adjacent cylinder bore walls are connected is known.

  In recent years, the engine room has been downsized due to the need to make the cabin as large as possible, and accordingly, the engine has been downsized. For example, in the longitudinal direction of the engine (cylinder arrangement direction) The length is shortened as much as possible to make it compact.

  In addition, the output of the engine is also increased. For example, the engine performance is improved by a supercharger.

  However, when high output is achieved in an engine that has been made compact as described above, since the space between the bores is shortened in the engine that has been made compact, the temperature near the top deck near the combustion chamber is reduced. Increases and heat load increases.

Therefore, Patent Document 1 below discloses that an X-shaped or V-shaped water channel is formed by drilling between cylinder bores to reduce the thermal load between the bores.
JP 2001-107801 A

  However, according to the above-mentioned Patent Document 1, there is a possibility that a defective hot water at the time of casting occurs at the time of drilling a water channel, and cooling water leaks.

  That is, normally, in the cylinder block, a communication water channel for guiding cooling water from the water jacket of the cylinder block to a cylinder head disposed on the cylinder block is provided in the vertical direction of the engine. This communication water channel is shown in FIG. In this way, the leg A of the core A extending in the vertical direction of the engine is formed, but in the process of filling the hot water during casting, the flow of hot water between the bores is disturbed by the leg a, and bubbles are There is a risk of staying in between and forming a so-called nest.

  Here, while the cylinder block is usually made of an aluminum alloy, the cylinder liner is made of cast iron, and since the materials of the two are different, the connectivity is not high.

  Therefore, as described above, when the bubble stays between the bores due to poor hot water surroundings and a nest is formed, when the water channel is drilled, the water channel, the cylinder block and the cylinder liner are in communication with each other by the nest, There is a risk that the cooling water leaks into the crankcase via the water channel, the nest, and between the cylinder liner and the cylinder block.

  The present invention has been made in consideration of the above-described problems, and an object of the present invention is to provide a cylinder block structure for a multi-cylinder engine and a method for manufacturing the same that can suppress cooling water leakage caused by formation of a communication water channel between the bores of the cylinder block. Is to provide.

In order to achieve the above object, the present invention provides the following solution as a solution. That is, in the first configuration of the present invention, a plurality of cylinders arranged in series are provided, and a water jacket is formed on the outer periphery of the cylinder by casting using a core, and on the inner periphery of the cylinder. Is a cylinder block structure of a multi-cylinder engine in which a cylinder liner made of a material different from the cylinder base material is cast,
While the first communication water passage communicating with the water jacket and top management deck surface around except the vicinity between the bore of the cylinder is formed by casting vent with the tang,
A pair of bottomed passages are formed by drilling between the bores of the cylinder so as to be opposed to each other from the top deck surfaces on both sides and communicate with each other on the tip side,
A water jacket formed by the core, a bottomed passage, and a second communicating water passage communicating with the top deck surface are formed by drilling below the bottomed water passage ,
The second communication water channel includes a small-diameter communication water channel formed at a position close to between the bores of the cylinder, a distance between the bores rather than the small-diameter communication water channel, and the small-diameter communication water channel and a part thereof in plan view of the cylinder block. A large-diameter communicating channel formed larger in diameter than the small-diameter communicating channel is formed at the overlapping position .

  According to the first configuration of the present invention, the peripheral water jacket except the vicinity between the bores of the cylinder and the first communication water channel communicating with the top deck surface are formed by casting using a core. Manufacturability can be maintained as much as possible.

  In addition, a pair of bottomed passages are formed by drilling between the bores of the cylinder so as to face each other from the top deck surfaces on both sides and communicate with each other at the tip side, and below the bottomed water channel Since the water communication channel formed by casting, the bottomed passage, and the second communication channel that communicates with the top deck surface are formed by drilling, when forming by casting, the core corresponding to the second communication channel between the bores Since there is no need to provide a leg portion, it is possible to suppress poor hot water caused by the leg portion.

  As a result, it is possible to suppress air bubbles from remaining between the bores when the second communication water channel is formed, thereby suppressing cooling water leakage.

  Here, in order to improve the cooling performance between the bores, it is desirable to form the communication water channel as close as possible between the bores. Therefore, in the case of forming by casting, generally along the inner wall of the cylinder between the bores. The shape is different. However, when the communicating water channel is formed by drilling as in the present invention, the shape of the communicating water channel is restricted to a circular shape, and thus cannot be formed along the cylinder inner wall. There is a risk of interference with the inner wall.

According to the first configuration of the present invention, the second communication water channel includes a small-diameter communication water channel formed at a position close to between the bores of the cylinder, a distance between the bores more than the small-diameter communication water channel, and a cylinder block plane. Since the small-diameter communication water channel and a part of the small-diameter communication water channel overlap with each other, the large-diameter communication water channel formed larger than the small-diameter communication water channel is formed. It can be approximated to a shape along the shape.

  As a result, the communication water channel can be brought close to the bores while suppressing interference with the cylinder inner wall between the bores, and the cooling performance can be improved.

In the second configuration of the present invention, the water jacket and the first communication water channel that communicates the water deck and the top deck surface excluding the space between the water jacket and the bore are formed on the outer periphery of the plurality of cylinders by casting using the core. A casting process for casting a cylinder block material for a cylinder block by casting a cylinder liner made of a material different from the cylinder base material on the inner periphery of the cylinder,
After the casting step, a bottomed water channel is formed by drilling a pair of bottomed water channels that are inclined to communicate with each other from the top deck surface on both sides between the bores of the cylinder block material so as to communicate with each other on the tip side. Processing steps,
After the bottomed water channel processing step, a leak inspection step of performing a leak inspection by supplying a fluid of a predetermined pressure to the bottomed water channel from the top deck surface of the cylinder block intermediate material that has undergone the processing step;
After the leak inspection step, a water jacket formed by the core below the bottomed water channel of the cylinder block intermediate material, and a second communication water channel communicating the bottomed water channel and the top deck surface are formed by drilling. And a communication channel processing step.

  Here, the cylinder block is normally subjected to a leak test on the formed water jacket. However, when performing a leak test on a bottomed water channel formed between bores as in the present invention, there is a concern that the leak test accuracy may deteriorate. There is.

  That is, the bottomed water channel is finally communicated including the water jacket and the top deck surface formed below the bottomed water channel when the second communication water channel is drilled. When the leak test is performed after processing all the water channels, the opening of the bottomed water channel is not opened on the top deck surface but on the side wall of the communication water channel.

  As a result, in the leak test, it is necessary to closely contact the inspection head for the leak test in a state where the inspection head is partially inserted inside the cylinder block from the top deck surface, but the inspection head is in the height direction of the cylinder block. Although it is easy to apply pressure, it is difficult to apply pressure in the lateral direction, it is not possible to ensure sufficient adhesion, and even if pressurized fluid is supplied to the bottomed water channel, the fluid leaks Because.

According to the second configuration of the present invention, after the bottomed water channel is formed, the leak test of the bottomed water channel is performed first before the second communication channel is formed. At this time, since the communication channel has not yet been formed, the bottomed channel is opened on the top deck surface.

  Therefore, even when a bottomed passage is formed, the leak test inspection head has a flat inspection head that is parallel to the top deck surface of the cylinder block and is in close contact with the top deck surface of the cylinder block. The leak test accuracy can be improved.

  In addition, since the second communication channel is formed after the leak test, the second communication channel can be formed without affecting the leak test accuracy as described above.

  ADVANTAGE OF THE INVENTION According to this invention, the cooling water leak accompanying the communication water path formation between the bores of a cylinder block can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view of a top deck surface of a cylinder block according to the embodiment as viewed from above, and FIG. 2 is a cross-sectional view taken along line AA of FIG.

  In FIG. 1, a cylinder block 1 is a cylinder block applied to, for example, a 4-cylinder inline gasoline engine, and is made of an aluminum alloy.

  The cylinder block 1 is a closed deck type with the top deck surface 1a closed and a so-called siamese type in which adjacent cylinder bore walls are connected. Four cylinders # 1 (first cylinder) and # 2 (second cylinder) , # 3 (3rd cylinder), # 4 (4th cylinder) are sequentially arranged.

  As shown in FIG. 2, water jackets WJ, WJ,... Extending in the height direction of the cylinder block 1 are formed on the outer periphery of each cylinder using a core when casting the cylinder block. The core used here is a collapsible one such as a shell core or a water-soluble core that has been used frequently.

  As shown in FIG. 1, for example, a cast iron cylinder liner 3 is cast on the inner circumference of each cylinder.

  A first communication water passage communicating with the water jacket WJ and the top deck surface 1a excluding the vicinity between the bores of the cylinder is formed by casting using the above-described core when the cylinder block 1 is cast.

  Also, in the vicinity of the cylinder bores, as shown in FIG. 2, a pair of bottomed water channels 4 are disposed so as to be opposed to each other from the top deck surface 1a on both sides of the cylinder bores so as to communicate with each other on the tip side. 4, a bottomed water channel 4, a water jacket 2 formed by casting below the bottom water channel 4, a top deck surface 1 a, and a small-diameter communication channel 5 that communicates the bottomed water channel 4, 4 (second communication according to claim 2). Equivalent to a water channel) and a larger diameter than the small-diameter communication channel 5 at a position where the small-diameter communication channel 5 and a part thereof overlap with the small-diameter communication channel 5 in a plan view. The communication channel 6 (corresponding to the second communication channel described in the claims) is formed by drilling.

  7, 7... Indicate fastening member insertion holes for fixing a cylinder head (not shown) on the cylinder block 1.

  Next, the manufacturing process of the cylinder block 1 is demonstrated based on FIG. 3 thru | or FIG.

  3 is a perspective view showing the core of the cylinder block according to the present embodiment, and FIG. 4 is a cross-sectional view taken along the line AA of FIG. 1 (before processing the small-diameter and large-diameter communication channels 5, 6 corresponding to the second communication channel). 5 is a plan view of the top deck surface of the cylinder block equipped with the leak tester seal member according to the embodiment as viewed from above, and FIG. 6 is a part of FIG. 5 (near the area between the bores of the second and third cylinders). 7 is an enlarged plan view, FIG. 7 is a schematic diagram showing an overall configuration of a leak test, and FIG. 8 is a block diagram showing a manufacturing process of a cylinder block according to this embodiment.

(Casting process)
First, in the cylinder block 1, a cylinder block material having a water jacket WJ therein is cast using the core 10 shown in FIG. Note that the leg 10a for forming the first communication channel 2 in the core 10 is shown representatively only for a part of the second and third cylinders in the center.

  At this time, the core 10 is not provided with leg portions a for forming the second communication water channel between the bores with respect to the conventional core shown in FIG. Only the jacket WJ is formed by casting.

  A cast iron cylinder liner 3 is cast around the inner periphery of each cylinder.

(Bottom waterway processing process)
Next, the cylinder block material cast as described above has a pair of tilted arrangements that are opposed to each other from the top deck surface 1a on both sides in the vicinity of the cylinder bore of the cylinder block material and communicate with each other on the tip side. The bottom water channels 4, 4 are drilled.

  At this time, as shown in FIG. 4, since the small diameter and large diameter communicating water channels 5 and 6 are not formed, the opening of the bottomed water channel is opened in the top deck surface 1a.

(Bottom waterway leak test process)
Next, a leak test is performed on the bottomed water channels 4 and 4 in the cylinder block intermediate material formed through the above-described processing steps.

  Specifically, as shown in FIGS. 5 and 6, on the top deck surface 1a of the cylinder block 1, a first section 11a (sixth section) for partitioning only the bottomed water channels 4 formed in the vicinity between the bores of the cylinder. In order to pressure-bond the sealing member 11 divided into the second compartment 11b (eight places) that divides each first communication water passage (water jacket) 2 formed by casting other than the bottomed water passage 4 The seal member 11 is disposed on an inspection head (not shown) facing the top deck surface 1a of the cylinder block 1, and an air supply / discharge system that can supply and discharge air by switching air to each of the first compartment 11a and the second compartment 11b. A leak tester 12 (not shown in FIGS. 5 and 6) is arranged.

  Although the detailed description of the leak tester 12 is omitted, for example, as shown in FIG. 7, a pressure source AP such as an air pump, a pressure sensor PS for detecting the pressure after the cylinder block 1 is pressurized, etc. Has been.

  And while opening the switching valve 14 arrange | positioned at the 1st pressurization channel | path 13 which connects the leak tester 12 and the 1st division (bottomed water channel 4) of the cylinder block 1, the leak tester 12 and the 2nd division (of the cylinder block 1) are opened. The second switching valve 16 disposed in the second pressurizing passage 15 communicating with the other water jacket 2) is closed, and predetermined pressurized air is sequentially supplied to each first section (the bottomed water channel 4). The leak test of the bottomed water channel 4 is performed simultaneously or sequentially.

  The leak test is a well-known technique. First, pressurize to a predetermined initial pressure, and then set the pressure in each passage at a predetermined time (a predetermined pressure lower than the initial pressure) when a predetermined time elapses. It is determined whether or not there is no leakage in the formed bottomed water channel 4 if it is maintained at a predetermined pressure or higher.

(Water jacket leak test process)
Next, a leak test is performed on the water jacket WJ, which is a cylinder block intermediate material.

  Specifically, contrary to the above-described leak test, the switching valve 14 disposed in the first pressurizing passage 13 that connects the leak tester 12 and the first section (bottomed water passage 4) of the cylinder block 1 is closed. The second switching valve 16 disposed in the second pressurizing passage 15 communicating the leak tester 12 and the second section (the other water jacket WJ of the cylinder block 1) is opened, and predetermined pressurized air is supplied to the water jacket WJ. The water jacket 2 will be sequentially tested for leaks.

(Second communication channel processing process)
Thereafter, the water jacket WJ, the top deck surface 1a, and the bottomed water channels 4 and 4 formed by casting below the bottomed water channel 4 and 4 are communicated with the intermediate material of the cylinder block formed through the above-described steps. The small-diameter communicating water channel 5 (corresponding to the second communicating water channel described in the claims) and a position farther from the bore than the small-diameter communicating water channel 5 and a part of the small-diameter communicating water channel 5 in a plan view of the cylinder block 1 overlap. A large-diameter communication channel 6 (corresponding to the second communication channel described in the claims) having a larger diameter than the small-diameter communication channel 5 is formed by drilling. (See Figure 2)
In addition, after this communication water channel processing, the leak test of the cylinder block 1 finally completed including other processing is performed, but the description is abbreviate | omitted here.

  As described above, according to the present embodiment, the peripheral water jacket WJ excluding the vicinity between the bores of the cylinder and the first communication water channel 2 communicating with the top deck surface 1a are formed by casting using a core. Manufacturability of the water jacket WJ can be maintained as much as possible.

  In addition, a pair of bottomed passages 4 are formed by drilling between the bores of the cylinders so as to face each other from the top deck surfaces 1a on both sides and communicate with each other on the tip side, and the bottomed water channels 4 Since the water jacket WJ, the bottomed passage 4 and the top deck surface 1a formed by casting are formed by drilling, the water jacket WJ formed by casting is formed by drilling. Since there is no need to provide the leg portion of the core for forming the small-diameter and large-diameter communication water passages 5 and 6 corresponding to the two communication water passages, it is possible to suppress the hot water circumference defect caused by the leg portions.

  As a result, it is possible to suppress bubbles from remaining between the bores when forming the small-diameter and large-diameter communicating water channels 5 and 6, and to suppress cooling water leakage.

  Here, in order to improve the cooling performance between the bores, it is desirable to form the communication water channel as close as possible between the bores. Therefore, in the case of forming by casting, generally along the inner wall of the cylinder between the bores. The shape is different. However, when the communicating water channel is formed by drilling as in the present invention, the shape of the communicating water channel is restricted to a circular shape, and thus cannot be formed along the cylinder inner wall. There is a risk of interference with the inner wall.

  On the other hand, according to the present embodiment, the communication water channel is a small-diameter communication water channel 5 formed at a position close to between the bores of the cylinder, and is farther from the bore than the small-diameter communication water channel 5. Since the small-diameter communication water channel 5 and a part of the small-diameter communication water channel 5 overlap with each other, the large-diameter communication water channel 6 is formed with a larger diameter than the small-diameter communication water channel 5. To approximate the shape along the shape between the bores.

  As a result, the second communication water channel constituted by the small-diameter and large-diameter communication water channels 5 and 6 can be brought close to the bores while suppressing interference with the cylinder inner wall between the bores, thereby improving the cooling performance. it can.

  In addition, after the bottomed water channel 4 is formed, a leak test of the bottomed water channel 4 is performed first before the small-diameter and large-diameter communication water channels 5 and 6 are formed. At this time, since the small-diameter and large-diameter communicating water channels 5 and 6 are not formed yet, the bottomed water channel 4 is opened to the top deck surface 1a.

  Therefore, even when the bottomed passage 1a is formed, the inspection head for leak test is sufficiently on the top deck surface 1a of the cylinder block 1 by the flat seal member 11 parallel to the top deck surface 1a of the cylinder block 1. A leak test can be performed in close contact with the substrate, and the leak test accuracy can be improved.

  In the present embodiment, the cylinder block 1 is made of aluminum alloy and the cylinder liner 3 is made of cast iron. However, the present invention can be applied to cylinder blocks and cylinder liners of other materials.

  In this embodiment, an example is shown in which the present invention is applied to the cylinder block 1 for an in-line four-cylinder gasoline engine. However, the present invention can also be applied to a gasoline engine having the number of cylinders and a cylinder block for a diesel engine.

The top view which looked at the top deck surface of the cylinder block regarding embodiment of this invention from the upper side. FIG. 1 is a cross-sectional view taken along the line AA in FIG. The perspective view which shows the core of the cylinder block regarding embodiment of this invention. FIG. 1 is a cross-sectional view taken along line AA of FIG. The top view which piled up the seal member for leak testers concerning the embodiment of the present invention on the top deck surface of a cylinder block, and was seen from the upper part side. FIG. 6 is a partially enlarged plan view of FIG. 5 relating to an embodiment of the present invention. 1 is a schematic diagram showing an overall configuration of a leak test according to an embodiment of the present invention. The block diagram which shows the manufacturing process of the cylinder block regarding this embodiment regarding embodiment of this invention. The perspective view which shows the core of the conventional cylinder block.

Explanation of symbols

1: Cylinder block 1a: Top deck surface 2: First communication water channel 3: Cylinder liner 4: Bottomed water channel 5: Small-diameter communication channel (second communication channel)
6: Large diameter communication channel (second communication channel)
10: Core 10a: Leg 11: Seal member 12: Leak tester 13: First pressurizing passage 14: Switching valve 15: Second pressurizing passage 16: Switching valve WJ: Water jacket

Claims (2)

A cylinder comprising a plurality of cylinders arranged in series, a water jacket formed by casting using a core on the outer periphery of the cylinder, and a cylinder made of a material different from the cylinder base material on the inner periphery of the cylinder In the cylinder block structure of a multi-cylinder engine in which the liner is cast,
While the first communication water passage communicating with the water jacket and top management deck surface around except the vicinity between the bore of the cylinder is formed by casting vent with the tang,
A pair of bottomed passages are formed by drilling between the bores of the cylinder so as to be opposed to each other from the top deck surfaces on both sides and communicate with each other on the tip side,
A water jacket formed by the core, a bottomed passage, and a second communicating water passage communicating with the top deck surface are formed by drilling below the bottomed water passage ,
The second communication water channel includes a small-diameter communication water channel formed at a position close to between the bores of the cylinder, a distance between the bores rather than the small-diameter communication water channel, and the small-diameter communication water channel and a part thereof in plan view of the cylinder block. A cylinder block structure for a multi-cylinder engine, wherein the cylinder block structure includes a large-diameter communication channel formed in an overlapping position with a larger diameter than the small-diameter communication channel . Casting using a core forms a water jacket on the outer periphery of a plurality of cylinders and a first communication water channel that communicates the top deck surface excluding the space between the water jacket and the bore, and a cylinder on the inner periphery of the cylinder. A casting process for casting a cylinder block material for a cylinder block by casting a cylinder liner made of a material different from the base material;
After the casting step, a bottomed water channel is formed by drilling a pair of bottomed water channels that are inclined to communicate with each other from the top deck surface on both sides between the bores of the cylinder block material so as to communicate with each other on the tip side. Processing steps,
After the bottomed water channel processing step, a leak inspection step of performing a leak inspection by supplying a fluid of a predetermined pressure to the bottomed water channel from the top deck surface of the cylinder block intermediate material that has undergone the processing step;
After the leak inspection step, a water jacket formed by the core below the bottomed water channel of the cylinder block intermediate material, and a second communication water channel communicating the bottomed water channel and the top deck surface are formed by drilling. The manufacturing method of the cylinder block of a multi-cylinder engine characterized by including a communicating channel processing process.

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