JP4027056B2 - Cylinder block of engine and casting method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine cylinder block suitable for suppressing an increase in engine lubricant consumption and exhaust gas contamination, improving the productivity of the cylinder block, and reducing manufacturing costs, and a casting method thereof.
[0002]
[Prior art]
As a method for casting an engine cylinder block, for example, one described in Japanese Utility Model Publication No. 58-137559 “Die-cast Cylinder Liner Material” is known.
[0003]
In FIG. 4 of the above publication, the core 36 is attached to the movable die 16, and the protrusion 37 provided on the core 36 is covered with a liner material 41 having a flange portion 43 projecting from the inner peripheral surface to the center side. A casting method is described in which the liner material 41 is positioned by sandwiching the portion 43 between the protruding portion 37 and the fixed mold 11.
[0004]
[Problems to be solved by the invention]
In the technique of the above publication, a process of removing the flange portion 43 of the liner material 41 by machining is required after casting, and since it is the back side in the cylinder block, the machining is not easy, and productivity and This is disadvantageous in terms of manufacturing costs.
[0005]
Further, for example, when the liner material 41 is made of cast iron and the cylinder block body is made of an aluminum alloy, when the cylinder block composed of the liner material 41 and the cylinder block body is incorporated in the engine and operated, the liner material 41 and the cylinder block A gap may occur between the liner material 41 and the cylinder block body due to the difference in thermal expansion between the block body and the block body.
[0006]
When such a gap is generated, the lubricating oil may enter the gap in the crankcase, ooze out into the combustion chamber, and burn.
As a result, the amount of lubricating oil consumed increases and the exhaust gas becomes dirty.
[0007]
Therefore, the object of the present invention is to (1) improve the cylinder block of the engine to suppress the increase in the amount of lubricating oil consumption of the engine and prevent exhaust gas contamination, and (2) in the method of casting the cylinder block of the engine, It is to improve the productivity of the cylinder block and reduce the manufacturing cost.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, claim 1 is a cylinder block of an engine in which a crankcase is integrally formed and a cylinder liner is cast, and a breather chamber for returning oil mist in the crankcase to the air cleaner side. It is provided on the side surface of the cylinder block, and a window portion is opened at the bottom of the breather chamber, and the outer surface of the cylinder liner and the breather chamber are communicated with each other through the window portion.
[0009]
When the lubricating oil in the crankcase enters between the cylinder block main body and the cylinder liner, this lubricating oil can be discharged to the breather chamber through the window, and the cylinder block main body and the cylinder liner It is possible to prevent the lubricating oil from oozing out into the combustion chamber, and it is possible to suppress the consumption amount of the lubricating oil from burning and to prevent the exhaust gas from becoming dirty.
[0010]
According to a second aspect of the present invention, there is provided an engine including a crankcase integrally formed, a cylinder liner cast, and a breather chamber provided on a side surface, and a window portion communicating the outer surface of the cylinder liner and the breather chamber at the bottom of the breather chamber. A cylinder block casting method, wherein a cylinder liner is placed on a shaft portion provided in a casting mold, and the cylinder liner is pressed by a window forming protrusion extending from a split mold of the casting mold. The casting is carried out while preventing the axial movement.
[0011]
By pressing the cylinder liner with the split window forming projections, the cylinder liner can be prevented from moving in the axial direction, and processing for removing the flange of the cylinder liner is performed after casting the cylinder block as in the past. There is no need to do it. Therefore, the productivity of the cylinder block can be improved and the manufacturing cost can be reduced.
[0012]
According to a third aspect of the present invention, the shaft portion is horizontal.
By making the shaft part horizontal, the casting mold can be made into a horizontally long layout.For example, compared with a vertically long casting mold, the present invention allows for handling at the time of installation or disassembly of the casting mold. Can be easily.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is an explanatory view of an engine incorporating a cylinder block according to the present invention. An engine 10 includes a cylinder block 11 in which a crankcase and a cylinder head are integrally formed, and a lower case 12 fitted to the lower portion of the cylinder block 11. A cylinder liner 15 is cast in a cylinder portion 14 formed at the center of the cylinder block 11, and a piston 16 is movably inserted into the cylinder liner 15, and a piston pin (not shown) is inserted into the piston 16. One end of the connecting rod 17 is attached, bearing attachment portions 21 and 22 are provided in the lower case 12 and the cylinder block 11, respectively, and the crankshaft 24 can be rotated by the bearings 23 and 23 attached to these bearing attachment portions 21 and 22. To support the crankshaft of this crankshaft 24 The lower end of the aforementioned connecting rod 17 is attached to the shaft (not shown), the toothed drive pulley 25 is attached to the crankshaft 24, the timing toothed belt 26 is hung on the toothed drive pulley 25, and the timing toothed belt 26 is Further, it is hung on a toothed cam pulley 27, this toothed cam pulley 27 is integrally attached to a cam 31 and a camshaft 32 that is a rotation shaft of the cam 31, and the head portion 33 is arranged above the cylinder portion 14. A rocker arm 34 that slides on the outer peripheral surface of the cam 31 is swingably attached to a rocker shaft (not shown), and the end of the rocker arm 34 is applied to the end of the intake valve 36 via an adjusting screw 35. The valve with the intake valve 36 attached to the head 33 Guided by the guide 37, showing a state of covering the upper head portion 33 in the head cover 38.
The lower part of the cylinder block 11 and the lower case 12 are members constituting the crankcase 40.
[0014]
Here, 41 is a lock nut that locks the adjustment screw 35, 42 is a valve spring that generates an elastic force on the side of closing the intake valve 36, and 43 is attached to the end of the intake valve 36 and receives one end of the valve spring 42. A spring receiving member, 44 is a spark plug, 45 and 45 are seal members, 46 is a main switch, 47 is an oil inlet cap, and 48 is a fuel chamber. Note that the exhaust valve and the parts for driving the exhaust valve are omitted.
[0015]
FIG. 2 is a side view of a cylinder block according to the present invention. The cylinder block 11 temporarily stores oil mist generated in the crankcase 40 (see FIG. 1) during engine operation, along with blow-by gas. A first breather chamber 51 (the first breather chamber 51 is the breather chamber described in claim 1 and 2) that is returned to the air cleaner (not shown) side is provided, and a window is provided at the bottom of the first breather chamber 51. The member 52 is a member in which the outer surface 15a of the cylinder liner 15 (see FIG. 1) and the first breather chamber 51 are communicated with each other through the window 52. Reference numeral 53 denotes a communication passage communicating with another breather chamber described later, and reference numeral 54 denotes an intake port serving as a supply passage for supplying air-fuel mixture to the combustion chamber 48 (see FIG. 1).
[0016]
FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2. A first breather chamber 51 is provided on the side of the cylinder block 11, specifically on the side of the cylinder liner 15, and a window portion 52 is provided in the first breather chamber 51. The formed state is shown.
[0017]
The cylinder block 11 is a member in which, for example, a cast iron cylinder liner 15 is cast on an aluminum alloy cylinder block main body 55, and the cylinder liner 15 is a cylindrical portion having a plurality of irregularities on the outer surface 15a. 56 and a flange portion 57 provided at the end of the cylindrical portion 56 and protruded from the outer surface 15a so that the outer diameter is larger than the diameter of the outer surface 15a.
[0018]
Here, 61 is an exhaust port through which exhaust from the combustion chamber 48 passes, 62 is a valve guide for guiding an exhaust valve (not shown), 63 is provided on the side surface of the cylinder block 11 opposite to the first breather chamber 51 and A second breather chamber connected to the first breather chamber 51 by the communication passage 53 (see FIG. 2), 64 a breather passage communicating with the second breather chamber 63 and the crankcase 40, 65 a valve seat on the intake side, 66 Is a valve seat on the exhaust side.
[0019]
4 is a cross-sectional view taken along line 4-4 of FIG. 2, and shows that the first breather chamber 51 is provided on the side of the cylinder liner 15. FIG.
An imaginary line 73 indicates a casting mold (a third mold that will be described in detail later) when the cylinder block 11 is die-cast with a casting mold, and this casting mold 73 is indicated by an arrow in the cylinder liner 15. When the mold is closed, it is applied to the outer surface 15 a of the cylinder liner 15.
Since the tip of the projection 83 (described in detail later) of the casting mold 73 has a shape that follows the outer surface 15a, the tip of the projection 83 can be brought into close contact with the outer surface 15a.
[0020]
As described above with reference to FIG. 3 and FIG. 4, the present invention firstly applies the crankcase 40 to the cylinder block 11 of the engine 10 (see FIG. 1) in which the crankcase 40 is integrally formed and the cylinder liner 15 is cast. A first breather chamber 51 that serves to return the oil mist in the case 40 to the air cleaner side is provided on the side surface of the cylinder block 11, and a window portion 52 is opened at the bottom of the first breather chamber 51. The outer surface 15a of the cylinder liner 15 and the first breather chamber 51 are communicated with each other.
[0021]
When the lubricating oil in the crankcase 40 enters between the cylinder block main body 55 and the cylinder liner 15, this lubricating oil can be discharged to the first breather chamber 51 through the window 52, and the cylinder block main body The lubricating oil between the cylinder liner 15 and the cylinder liner 15 can be prevented from oozing into the combustion chamber 48, the consumption amount of the lubricating oil can be suppressed, and the combustion products generated by the combustion of the lubricating oil This can prevent the exhaust gas from getting dirty.
[0022]
FIG. 5 is a cross-sectional view illustrating a die-casting mold for a cylinder block according to the present invention. A die-casting mold 70 as a casting mold according to claim 2 is moved horizontally to move the head portion of the cylinder block. 3. A first mold 71 as a split mold according to claim 2 for molding each part of the cylinder part and the crankcase, and a second mold 72 for molding the head part of the cylinder block by facing the first mold 71. And a third mold 73 and a fourth mold 74 that mold the side surface of the cylinder block, and a fifth mold 75 that molds the side surface of the cylinder block by closing the mold in a direction perpendicular to the paper surface (each part of the fifth mold 75 is In order to show that they are integrated, each part is provided with a leader line.) And a sixth mold (not shown) opposed to the fifth mold 75. To attaching a die casting apparatus for injecting hot water (not shown).
[0023]
Here, reference numeral 81 denotes a cylindrical shaft portion provided in the first die 71, which is a portion formed to have an outer diameter slightly smaller than the inner diameter of the cylinder liner 15 (see FIG. 3). Reference numeral 82 denotes an annular surface provided in the first mold 71, which is a portion that contacts the cylinder liner 15 and positions the cylinder liner 15. Reference numeral 83 denotes a protrusion provided on the third mold 73 (the protrusion 83 is the window portion forming protrusion described in claim 2), and is a portion forming the window portion 52 of the first breather chamber 51 shown in FIG. It is.
[0024]
The casting procedure of the cylinder block described above will be described next.
FIG. 6 is a first operation view for explaining the casting procedure of the cylinder block according to the present invention.
First, the cylinder liner 15 may be fitted to the shaft portion 81 of the first die 71 in the die casting mold, and the end surface 15b of the cylinder liner 15 (the end surface 15b may be the end surface of the flange portion 57) on the annular surface 82 of the first die 71. ) To position the cylinder liner 15.
[0025]
FIG. 7 is a second operation view for explaining the casting procedure of the cylinder block according to the present invention. The first die 71 fitted with the cylinder liner 15 in FIG. 6 is shown by arrows (1) and (1) in FIG. The state in the middle of mold closing with the 2nd type | mold 72 is shown.
[0026]
The closing speed of the first mold 71 is controlled by a control device (not shown) so that the cylinder liner 15 does not shift to the left with respect to the first mold 71. Here, the outline of the cavity 77 is indicated by an imaginary line.
[0027]
FIG. 8 is a third operation view for explaining the casting procedure of the cylinder block according to the present invention. The third die 73 and the fourth die 74 are moved from the side of the cylinder liner 15 as indicated by arrows (2) and (2). The state during the mold closing is shown.
The mold closing of the third mold 73 and the fourth mold 74 is performed after the mold closing of the first mold 71 and the second mold 72 is completed.
[0028]
FIG. 9 is a fourth action diagram for explaining the casting procedure of the cylinder block according to the present invention. After completion of the closing of the third die 73 and the fourth die 74, the fifth die 75 (▲ 3 ▼) and the state where the sixth mold is closed.
[0029]
FIG. 10 is a fifth operation view for explaining the casting procedure of the cylinder block according to the present invention, and is an enlarged view of the main part of FIG.
When the mold closing of the third mold 73 is completed, the projection 83 of the third mold 73 is adjacent to the flange portion 57 of the cylinder liner 15, and the tip of the projection 83 is in contact with the outer surface 15 a of the cylinder liner 15. In this way, the cylinder liner 15 is positioned in the axial direction by the annular surface 82 of the first mold 71 and the protrusion 83 of the first mold 72.
[0030]
In FIG. 9, when the closing of the die casting mold 70 is completed, the molten metal is injected into the cavity 77 from the die casting apparatus and filled.
When the molten metal is solidified, the die-casting mold 70 is opened and the cylinder block cast product is taken out.
The cylinder block cast product has a first breather chamber 51 (see FIG. 3) formed by the third mold 73, and a window portion 52 (see FIG. 3) formed by the protrusion 83.
[0031]
As described above with reference to FIGS. 3, 9 and 10, the present invention secondly forms the crankcase 40 integrally, casts the cylinder liner 15, and includes the first breather chamber 51 on the side surface. A casting method of a cylinder block 11 of an engine 10 (see FIG. 1) having a window portion 52 that communicates an outer surface 15a of a cylinder liner 15 and a first breather chamber 51 at the bottom of a first breather chamber 51, The cylinder liner 15 is put on a shaft portion 81 provided in the mold 70, and the cylinder liner 15 is pressed by a protrusion 83 extending from the third mold 73 of the die-casting mold 70, so that the axial direction of the cylinder liner 15 is increased. Casting is performed while preventing movement.
[0032]
In the cylinder head integrated cylinder block 11 according to the present invention, it is difficult to position the cylinder liner 15 by sandwiching both ends of the cylinder liner 15 during casting. However, the projection 83 of the third mold 73 causes the cylinder liner 15 to be moved from the side. By pressing, it is possible to prevent the cylinder liner 15 from moving in the axial direction, and there is no need to perform a process for removing the flange portion of the cylinder liner after casting the cylinder block as in the prior art. Therefore, the productivity of the cylinder block 11 can be improved and the manufacturing cost can be reduced.
[0033]
In addition, since the cylinder liner 15 is prevented from moving in the axial direction, even when high-pressure molten metal is injected into the cavity 77, there is a concern that the cylinder liner 15 may be displaced with respect to the shaft portion 81 of the first mold 71 due to the flow of the molten metal. Absent.
[0034]
Third, the present invention is characterized in that the shaft portion 81 is horizontal.
By making the shaft portion 81 horizontal, the die-casting mold 70 can have a horizontally long layout. For example, in the present invention, compared to a vertically long casting mold, Handling during dismantling can be facilitated.
[0035]
In the embodiment of the present invention, in FIG. 9, a flange portion 57 is provided at the right end of the cylinder liner 15, and the projection 83 of the third mold 73 is disposed on the left side of the flange portion 57, thereby Although the movement in the axial direction is restricted, the present invention is not limited to this, and the protrusion is inserted into the side surface of the cylinder liner 15, for example, the concave portion provided on the outer surface 15 a of the cylinder liner 15, and the tip of the projection is applied to the bottom of the concave portion Thus, the axial movement of the cylinder liner may be restricted.
Further, the axial movement of the cylinder liner 15a may be restricted by simply pressing a protrusion against the outer surface 15a (regardless of location) of the cylinder liner 15.
[0036]
【The invention's effect】
The present invention exhibits the following effects by the above configuration.
The cylinder block of the engine according to claim 1 is provided with a breather chamber that plays a role of returning oil mist in the crankcase to the air cleaner side on the side of the cylinder block, and a window is formed at the bottom of the breather chamber. Since the outer surface of the cylinder liner and the breather chamber are communicated with each other, when the lubricating oil in the crankcase enters between the cylinder block body and the cylinder liner, this lubricating oil is passed through the window to the breather chamber. It can be discharged, the lubricating oil between the cylinder block main body and the cylinder liner can be prevented from oozing into the combustion chamber, the consumption amount due to the combustion of the lubricating oil can be suppressed, and the exhaust gas becomes dirty. Can be prevented.
[0037]
According to a second aspect of the present invention, there is provided a method for casting a cylinder block of an engine, wherein a crankcase is integrally formed and a cylinder liner is cast, and a breather chamber is provided on a side surface, and the outer surface of the cylinder liner communicates with the breather chamber at the bottom of the breather chamber. A method for casting a cylinder block of an engine having a window portion, wherein a shaft liner provided in a casting mold is covered with a cylinder liner, and the cylinder liner is extended from a split mold of the casting mold. Since the casting is carried out while preventing the cylinder liner from moving in the axial direction by being pressed by the protrusions, it is not necessary to perform a process for removing the flange portion of the cylinder liner after casting the cylinder block as in the prior art. Therefore, the productivity of the cylinder block can be improved and the manufacturing cost can be reduced.
[0038]
In the method of casting the cylinder block of the engine according to claim 3, since the shaft portion is horizontal, the casting mold can be in a horizontally long layout. For example, compared with a vertically long casting mold, in the present invention, The handling at the time of installation and dismantling of the casting mold can be facilitated.
[Brief description of the drawings]
FIG. 1 is an explanatory view of an engine incorporating a cylinder block according to the present invention. FIG. 2 is a side view of the cylinder block according to the present invention. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. Fig. 5 is a cross-sectional view taken along line 4-4 of Fig. 5. Fig. 5 is a cross-sectional view illustrating a die-casting die for a cylinder block according to the present invention. Fig. 6 is a first action diagram illustrating a casting procedure for a cylinder block according to the present invention. FIG. 8 is a third action diagram illustrating the casting procedure of the cylinder block according to the present invention. FIG. 9 is a third action diagram illustrating the casting procedure of the cylinder block according to the present invention. FIG. 10 is a fifth action diagram for explaining the casting procedure of the cylinder block according to the present invention.
DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Cylinder block, 15 ... Cylinder liner, 15a ... Outer surface of cylinder liner, 40 ... Crankcase, 51 ... Breather chamber (1st breather chamber), 52 ... Window part, 70 ... Casting die (die casting casting) (Mold), 71 ... first mold, 73 ... divided mold (third mold), 81 ... shaft, 83 ... projection.

Claims (3)

In a cylinder block of an engine in which a crankcase is integrally formed and a cylinder liner is cast,
A breather chamber for returning oil mist in the crankcase to the air cleaner side is provided on the side of the cylinder block, and a window is opened at the bottom of the breather chamber, and the outer surface of the cylinder liner and the breather chamber are opened through the window. The cylinder block of the engine characterized by having communicated. A method for casting a cylinder block of an engine, in which a crankcase is integrally formed, a cylinder liner is cast, a breather chamber is provided on a side surface, and a window portion is provided at the bottom of the breather chamber to communicate the outer surface of the cylinder liner and the breather chamber. Because
The shaft liner provided in the casting mold is covered with the cylinder liner, and the cylinder liner is pressed by a window forming projection extending from the split mold of the casting mold, thereby preventing the cylinder liner from moving in the axial direction. A method for casting a cylinder block of an engine, characterized by performing casting. 3. The method of casting an engine cylinder block according to claim 2 , wherein the shaft portion is horizontal.

Images