JP2001241354A - Cylinder block structure of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder block structure of an engine having a simple composition, wherein the liquid draining property of a plating solution in plating treatment work is improved to reduce a take-out quantity of the plating solution and a working property is improved. SOLUTION: In a cylinder block 12 of the engine 2 provided with the first water jacket 11 for cooling a cylinder part 6, an opening 12a and a fitting screw hole 12b for fitting a cylinder head 17 are formed on a surface 13 mating with the cylinder head 17. The opening 12a is communicated to the first water jacket 11 and the second water jacket 20 on the side of the cylinder head 17. Within the cylinder block 12, a communication hole 36 is extended in a cylinder arrangement direction, the first passage 38 communicating the communication hole 36 within a crankcase is formed on the side wall part of the crankcase, and a prepared hole 12c is formed as the second passage communicating the screw hole 12b to the communication hole 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an engine, and more particularly to a structure of a cylinder block for plating a piston sliding surface of a cylinder.

[0002]

2. Description of the Related Art Conventionally, the structure of a motorcycle engine is as follows.
In general, a cylinder block and a crankcase are formed separately, and a sleeve for sliding a piston is disposed in the cylinder block by press-fitting or casting. Further, the cylinder block is also known in which an inner surface of a cylinder bore, that is, a piston sliding surface is subjected to SCEM plating. When plating the piston sliding surface, the entire cylinder block is immersed in a plating solution, and an electrode is inserted into the center of the cylinder to perform plating. After the completion, the cylinder block is pulled up from the plating tank to drain the plating solution, and the operation is completed.

In recent years, in order to improve engine productivity, there has been a demand for a reduction in the number of parts, a reduction in the number of mounting (tightening) points, a reduction in size and weight, a reduction in cost, and the like. When the cylinder block and the crankcase are configured separately as in the past, positional accuracy for assembling both parts is required, and processing accuracy for ensuring sealing performance is required. And the need for assembling man-hours and the like.

[0004] In order to solve the above-mentioned problems and improve the productivity, there has been proposed an integrated structure of a cylinder block and a crank housing as disclosed in JP-A-11-182322. . JP-A-11-
According to 182322, in the cylinder block, the cylinder portion having the piston sliding surface and the upper half portion of the crankcase are integrally formed, and a plating film is formed only on the piston sliding surface. According to this, it is possible to reduce the number of parts, the number of manufacturing steps, and the like.

[0005]

However, when plating is performed on the piston sliding surface, since the cylinder block is conventionally configured as a single body, the shape is not complicated, and the work of draining the plating solution is easy. However, according to the configuration of the disclosed example, since the cylinder block and a part of the crankcase are formed integrally, the parts become large, and the parts become large and complicated, and the plating process, especially the plating solution, is performed. However, there is a problem that the liquid draining operation is difficult. In addition, if the drainage is poor, there is a problem that the plating solution is taken out of the plating tank more than necessary and the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has a simple structure to improve the drainage of a plating solution in a plating operation, reduce the amount of plating solution taken out, and It is an object of the present invention to provide a cylinder block structure of an engine with improved workability.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a cylinder block of an engine having a plurality of cylinder portions having a piston sliding surface and a first water jacket for cooling the cylinder portions. An opening for communicating the first water jacket and the second water jacket on the cylinder head side and a mounting screw hole for mounting the cylinder head are formed on the mating surface of the cylinder block. Along with a communication hole extending in the cylinder arrangement direction, a first passage communicating the communication hole into the crank chamber is formed in a side wall portion of the crank chamber of the cylinder block. An engine cylinder block structure, wherein a second passage communicating with the communication hole is formed. That.

[0008] It is preferable that the second passage penetrates a lower hole of a mounting screw hole of the cylinder head into the communication hole, and communicates the mounting screw hole with the communication hole.
It is preferable that a plating film is formed on the piston sliding surface, and the plating solution in the cylinder block after plating is discharged from the mating surface side with the cylinder head.

The piston sliding surface has a plating film formed thereon. The two cylinder blocks are brought into close contact with the mating surfaces of the two cylinder blocks and the cylinder head to perform plating, and the plating in the cylinder block after plating is performed. It is preferable that the plating liquid in the upper cylinder block is discharged through the second passage in the lower cylinder block while the cylinder blocks are vertically stacked.

According to the present invention, the communication passage extends in the cylinder arrangement direction inside the cylinder block, and the first passage connects the communication hole to the crank chamber on the side wall of the crank chamber of the cylinder block. By reducing the weight of the cylinder block,
Pressure fluctuations in the cylinder below the piston due to the vertical movement of the piston during engine operation can be reduced.
Further, by forming a second passage communicating the mounting screw hole of the cylinder head with the communication hole, the plating solution can be more easily supplied than the second passage when plating the piston sliding surface of the cylinder portion. Can be discharged.

Further, by penetrating the pilot hole of the mounting screw hole of the cylinder head into the communication hole, the second passage can be formed with a simple structure and without greatly changing the cylinder block, that is, without impairing the basic performance. Can be formed.

Further, by forming a plating film on the sliding surface of the piston, there is no need to provide a cylinder liner. Therefore, the number of parts can be reduced and the cost can be reduced. In addition, the plating solution in the cylinder block after the plating process is discharged from the mating surface side with the cylinder head, that is, by taking out the cylinder block from the plating tank with the mating surface facing downward, the water of the cylinder block is removed. The plating solution in the jacket can be discharged, and at the same time, the plating solution accumulated inside the cylinder block (when the inside is formed in a concave shape) can be discharged through the second passage. Therefore,
The plating solution can be easily drained without rotating the cylinder block.

[0013] In addition, the two cylinder blocks can be plated at the same time by closely joining the mating surfaces of the two cylinder blocks with the cylinder head, thereby reducing the number of plating operations. Also, by tightly joining the mating surfaces, it is possible to prevent the plating solution from flowing into the water jacket, and to allow the plating solution in the upper cylinder block to pass through the second passage in the lower cylinder block. Therefore, the plating solution can be safely and easily drained without rotating a heavy and large cylinder block.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an overall view showing the configuration of a motorcycle equipped with an engine according to an embodiment of the present invention, FIG. 2 is an explanatory view showing the overall configuration of the engine, and FIG.
4 is a partial cross-sectional assembly view showing the entire cylinder block structure of the engine, FIG. 4 is a side view showing the configuration of the upper case according to the present embodiment, FIG. 5 is a view taken in the direction of arrow X in FIG. 4, and FIG. FIG. 7 is a sectional view taken along line AA of the upper case shown in FIG. 4, FIG. 8 is a sectional view taken along line BB of the upper case shown in FIG. 6, and FIG. 9 is an upper case shown in FIG. FIG. 10 is an explanatory view showing a state when plating processing is performed on the piston sliding surface.

In this embodiment, as shown in FIGS. 1 and 2, an engine 2 is disposed on a motorcycle 1 substantially below a center portion of a body frame 3 and a crankshaft 4 is disposed horizontally with respect to the traveling direction of the vehicle body. An air cleaner box 7 is disposed above the engine 2 via a body frame 3, and further suspended above the engine 2. A fuel tank 8 is disposed so as to surround the upper side of the fuel tank 7. A radiator 9 is disposed forward of the engine 2 in the vehicle body traveling direction.

As shown in FIGS. 2 to 5, the engine 2 is a four-cycle four-cylinder engine having four cylinder portions 6 formed in parallel, and has a water jacket 11 for cooling the cylinder portions. A cylinder block 12 having an upper case 14, a middle case 15, and a lower case 16 including the cylinder block 12. The upper and lower split crankcases 10 are roughly divided into a cylinder head 17, an upper case 14, and a middle case. The case 15 and the lower case 16 are arranged in this order.

An exhaust manifold 18 is provided on the front side of the cylinder head 17 in the vehicle body traveling direction, and an intake manifold 19 is provided on the rear side of the cylinder head 17 in the vehicle body traveling direction. A cooling manifold is provided near the exhaust manifold 18 and the intake manifold 19. The second water jacket 20 is formed. An exhaust pipe 21 is connected to a front side of the exhaust manifold 18 in the vehicle traveling direction. The exhaust pipe 21 extends downward along the front side of the engine 2 main body, extends around the lower side of the engine 2, and extends toward the rear of the vehicle body. A throttle body 22 is disposed behind the intake manifold 19 in the vehicle body traveling direction, and communicates with the air cleaner box 7 via the throttle body 22. The air cleaner box 7 has a breather cover 25 mounted on the middle case 15 via a breather hose 24 connected to a lower rear end of the air cleaner box 7.
Is in communication with

A union 27 for cooling water is disposed on the rear side of the upper case 14 in the vehicle traveling direction, and is connected to a later-described water pump 29 via a water hose (cylinder block side) 28. The lower case 16
An oil pan 30 is disposed below the oil pump 30, an oil filter 31 is disposed on the front side in the vehicle body traveling direction, and a water pump 29 is disposed substantially at the center of the lower case 16 and on the left side in the vehicle body width direction. The water pump 2
Numeral 9 is connected to the radiator 9 via a water hose (radiator side) 33 on the radiator 9 side, and supplies the cooling water cooled by the radiator 9 to the water pump 29.
The cylinder block 12 via the union 27
And water jackets 11 and 20 formed in the cylinder head 17 to be described later.

As shown in FIGS. 3 and 4, the upper case 14 has a cylinder block 12 integrally formed at an upper portion and a crank chamber upper portion 14a formed at a lower portion. As shown in FIGS. 3 to 9, the cylinder block 12 has four cylinder portions 6 arranged side by side. A first water cooling portion is provided on the outer periphery of the cylinder portion 6 from substantially the center to the upper portion in the longitudinal direction of the cylinder. A jacket 11 is formed. The union 27 is arranged at substantially the same height as the first water jacket 11.

As shown in FIGS. 3, 7, and 8, an oil passage 35 is provided in front of the cylinder block 12 in the vehicle body traveling direction below the first water jacket 11 in the cylinder arrangement direction in the width direction of the cylinder block 12. Is extended. Inside the rear wall of the cylinder block 12 in the vehicle body traveling direction, a communication hole 36 having substantially the same height as the oil passage 35 and a lower portion of the first water jacket 11 is provided.
Are formed.

The communication hole 36 extends in the cylinder arrangement direction inside the rear wall, and is formed in the vicinity of the outside of the rotation locus 40 of the crankshaft 4 due to the outer end of the crank web (not shown). A first passage 38 that connects the communication hole 36 into the crank chamber is formed in the side wall of the crank chamber of the cylinder block 12.

As shown in FIGS. 6 and 7, the first passage 38 is formed at the rear side of the cylinder block 12 in the vehicle body traveling direction with respect to each of the cylinder portions 6 at two locations to be described later. 38a is an upper portion 36a of the communication hole 36.
And the lower side is open to the crank chamber. As shown in FIG. 5, the first water jacket 11 and the second water jacket 20 formed on the cylinder head 17 communicate with the mating surface 13 of the cylinder block 12 with the cylinder head 17. An opening 12a and a mounting screw hole 12b for mounting the cylinder head 17 are formed.

A part of the mounting screw hole 12b is disposed above the communication hole 36, and three insides thereof (FIG. 5).
The pilot hole 12c (marked with * in the middle) reaches the communication hole 36, and the mounting screw hole 12b and the communication hole 36 are communicated by the pilot hole 12c as a second passage.

The communication hole 3 of the cylinder block 12
In the vicinity of the lower side of the cylinder 6, the inner wall of the cylinder block 12 and the outer wall of the cylinder 6 are connected at a substantially central portion in the circumferential direction of each cylinder 6 in a direction perpendicular to the cylinder arrangement direction to form a bridge 44. Are formed.

The positional relationship between the first water jacket 11 and the communication hole 36 is such that the lower portion 11a of the first water jacket 11 is substantially flush with the apex 41a of the piston 41 at the time of the bottom dead center of the piston 41. The communication hole 36 has its upper portion 36a disposed below the apex 41a of the piston 41 at the bottom dead center of the piston 41,
The lower portion 36b of the communication hole 36 is disposed at substantially the same height as the lower end of the skirt portion 42 on the inner wall of the cylinder.

Next, the plating treatment of the piston sliding surface of the cylinder block will be described with reference to the drawings. FIG.
FIG. 4 is an explanatory view showing a state when plating processing is performed on a piston sliding surface according to the present embodiment. Cylinder block 12
When plating is performed on the piston sliding surface 6a, the plating is usually performed by electrolytic plating.

First, as shown in FIG. 10, the mating surfaces 13 of the two upper cases 14 with the cylinder head 17 of the cylinder block 12 are overlapped.
The two mating surfaces 13 are tightly fixed by sandwiching between two set jigs 52 and tightening them with four mounting bolts 54. The set jig 52 has a rectangular plate shape, and an opening 53 smaller than the opening 14b is formed substantially at the center at a position facing the opening 14b of the upper case 14.

Next, with the two upper cases 14 superimposed substantially vertically, one of the upper cases 14 is placed in the plating solution 51 in the plating tank 50 with the crankcase side of the upper case 14 facing down. Immerse. The electrode rod 55 is disposed substantially vertically at substantially the center in the cylinder. Then, electrolytic plating of the piston sliding surface 6a is performed.

After the plating process is completed, the two upper cases 14 are pulled up substantially vertically from the plating tank 50 to drain the plating solution. At this time, since the upper case 14 disposed on the lower side is opened downward, the plating solution is drained without the plating solution remaining in the case. On the other hand, in the case of the upper case 14 disposed on the upper side, since the entire shape is opened upward in a bowl shape, most of the plating solution is discharged from the opening of the cylinder portion, but the plating solution is accumulated in the case. easy.

However, the shape of the inside of the case is formed by a substantially curved surface, and the first passage 38 is arranged at the lowest position in an inverted state. It flows into the first passage 38. The plating solution flowing into the first passage 38 enters the communication hole 36,
Lower hole 12 of mounting screw hole 12b penetrating through communication hole 36
c and is discharged out of the upper case 14.

Here, since the mounting screw holes 12b of the upper upper case 14 and the mounting screw holes 12b of the lower upper case 14 are opposed to each other and overlap, the plating discharged from the upper mounting screw hole 12b. The liquid enters the lower mounting screw hole 12b and passes through the communication hole 36 to the first mounting screw hole 12b.
From the passage 38. Therefore, all the plating solution accumulated in the upper upper case is discharged.

According to the above configuration, the cylinder block 1
Since the communication hole 36 extends in the cylinder arrangement direction inside the cylinder block 2 and the first passage 38 that connects the communication hole 36 into the crank chamber is formed in the side wall of the crank chamber of the cylinder block 12, the cylinder The weight of the block 12 is reduced, and the piston 41 is operated when the engine is running.
Pressure fluctuation in the cylinder section 6 below the piston 41 due to the vertical movement of the piston 41 can be reduced. Further, since the lower hole 12c of the mounting screw hole 12b penetrates the communication hole 36 as a second passage connecting the mounting screw hole 12b of the cylinder head 17 and the communication hole 36, the piston sliding surface of the cylinder portion 6 When the plating process is performed on 6a, the plating solution can be easily discharged from the prepared hole 12c of the mounting screw hole 12b.

Further, since the pilot hole 12c of the mounting screw hole 12b of the cylinder head 17 has penetrated the communication hole 36, the second passage can be formed with a simple structure and without greatly changing the cylinder block 12, so that the second passage can be formed easily. The communication between the mounting screw hole and the communication hole can be established.

Further, since the plating film is formed on the piston sliding surface 6a, there is no need to provide a cylinder liner, and therefore, the number of parts can be reduced and the cost can be reduced. Further, the plating solution in the cylinder block 12 after the plating process is applied to the mating surface 13 with the cylinder head 17.
If the cylinder block 12 is taken out from the plating tank with the mating surface 13 facing downward, the plating solution in the water jacket 11 of the cylinder block 12 is discharged, and at the same time,
The plating solution accumulated inside the cylinder block 12 (when the inside is formed in a concave shape) can be discharged through the prepared hole 12c of the mounting screw hole 12b. Therefore, the plating solution can be easily drained without rotating the cylinder block 12.

Further, the mating surfaces of the two cylinder blocks 12 with the cylinder heads 17 are closely joined and the two cylinder blocks 12 are plated at the same time, so that the number of plating operations can be reduced. In addition, the mating surfaces 13 of the cylinder block 12 are opposed to each other, and are closely joined and vertically overlapped, so that the plating solution can be prevented from flowing into the water jacket 11, and
Since the plating solution in the upper cylinder block 12 can be discharged through the pilot hole 12c in the lower cylinder block 12, the plating solution can be drained safely and easily without rotating the heavy cylinder block 12. can do.

The structure of the cylinder block of the engine of the present invention is not limited to the above-described example.
It goes without saying that various changes can be made without departing from the spirit of the present invention. For example, in the present embodiment, the second
Although the pilot hole 12c of the mounting screw hole 12b is extended to the communication hole 36 as a passage of the present invention, as a modified example, it is not limited to a hole formed by drilling, but a hole formed as a cast hole. It may be.

[0037]

As described above, the first aspect of the present invention is as described above.
According to the cylinder block structure of the engine described in
With a simple configuration, the plating solution can be drained without rotating a heavy cylinder block during the plating process. That is, it is possible to provide a cylinder block structure of an engine in which the drainage of the plating solution is improved, the amount of the plating solution carried out is reduced, and the workability is improved.

[Brief description of the drawings]

FIG. 1 is an overall view showing a configuration of a motorcycle equipped with an engine according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an overall configuration of the engine.

FIG. 3 is a partially sectional assembly view showing the entire cylinder block structure of the engine according to the embodiment.

FIG. 4 is a side view showing a configuration of an upper case according to the embodiment.

FIG. 5 is a view of the upper case in FIG. 4 as viewed from an arrow X.

FIG. 6 is a view of the upper case of FIG.

7 is a sectional view of the upper case of FIG. 4 taken along the line AA.

8 is a cross-sectional view of the upper case of FIG. 6 taken along line BB.

9 is a cross-sectional view of the upper case of FIG. 6 taken along the line CC.

FIG. 10 is an explanatory diagram showing a state when a plating process is performed on a piston sliding surface according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Engine 4 Crankshaft 6 Cylinder part 6a Piston sliding surface 11 First water jacket 11a Lower side 12 Cylinder block 12a Opening 12b Mounting screw hole 12c Lower hole 13 Fitting surface 14 Upper case 14a Crank chamber upper part 17 Cylinder head 20 Second water jacket 35 Oil passage 36 Communication hole 36a Upper part 36b Lower part 38 First path 38a Upper part 40 Rotation trajectory 41 Piston 41a Piston apex position (bottom dead center) 42 Skirt part 44 Bridge part 50 Plating tank 51 Plating solution 52 Set jig 53 Opening 54 Bolt 55 Electrode rod

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F02F 1/10 F02F 1/10 DF term (reference) 3G024 AA06 AA24 AA36 AA38 AA47 CA02 CA05 DA01 DA03 DA10 DA18 EA05 FA14 GA18 GA26 4K024 BB04 BC10 CB19 GA16

Claims (4)

[Claims] 1. An engine cylinder block comprising: a plurality of cylinder portions having a piston sliding surface; and a first water jacket for cooling the cylinder portions. An opening for communicating the water jacket and the second water jacket on the cylinder head side and a mounting screw hole for mounting the cylinder head are formed, and are communicated in the cylinder arrangement direction inside the cylinder block. A second passage extending in the crank chamber side wall of the cylinder block, the first passage communicating the communication hole into the crank chamber, and a second screw hole communicating with the mounting screw hole of the cylinder head; A cylinder block structure for an engine, wherein a passage is formed. 2. The communication device according to claim 2, wherein the second passage penetrates a lower hole of a mounting screw hole of the cylinder head into the communication hole, and communicates the mounting screw hole with the communication hole. Item 2. An engine cylinder block structure according to item 1. 3. A plating film is formed on the sliding surface of the piston, and a plating solution in the cylinder block after the plating process is discharged from a mating surface side with a cylinder head. Engine cylinder block structure. 4. A plating process is performed on the sliding surface of the piston on which a plating film is formed, and the mating surfaces of the two cylinder blocks with the cylinder head are closely bonded to each other,
The plating solution in the cylinder block after the plating process is such that the plating solution in the upper cylinder block is discharged through the second passage in the lower cylinder block while the cylinder blocks are vertically stacked. The engine cylinder block structure according to claim 1 or 2, wherein: