JP3616616B2 - Bore pin for cylinder block casting - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a bore block for casting a cylinder block, and more particularly, to a cooling structure for a bore pin for casting a linerless cylinder block in which a cylinder liner is not present and a molten material becomes a cylinder bore as it is.
[0002]
[Prior art]
The cylinder block casting bore pin has a base end fixed to the mold, a distal end projecting into the mold cavity, and molten metal is cast around it to form a cylinder bore. Then, for the purpose of preventing the thermal expansion of the bore pin and the purpose of cooling the molten metal around the bore pin, a coolant is supplied into the bore pin.
[0003]
According to the bore pin cooling structure described in Japanese Patent Application Laid-Open No. 6-71405, a bore pin main body whose base end side is fixed to a mold, and a coolant pipe that extends from the base end side of the bore pin main body and is coaxially disposed on the bore pin main body. Prepare. The coolant pipe is composed of an injection pipe and a discharge pipe, and extends partway along the axial direction of the bore pin body. A cooling chamber communicating with the coolant pipe and extending in a straight line with the coolant pipe is formed on the distal end side of the bore pin main body. When the coolant is introduced from the injection pipe into the cooling chamber on the proximal end side of the bore pin body, cooling is performed on the distal end side of the bore pin. The coolant passes through the discharge pipe and is discharged from the base end side of the bore pin.
[0004]
[Problems to be solved by the invention]
In order to increase the cooling to the molten metal cast around the bore pin, it is necessary to increase the diameter of the cooling chamber and reduce the wall pressure of the bore pin around the cooling chamber. In particular, when casting a linerless cylinder block, since the molten material becomes the cylinder bore as it is, further cooling is required. However, if the cooling is insufficient, the molten metal will be stuck and seized. In addition, a void is generated on the bore surface.
[0005]
Moreover, the following problems occur even if the inside diameter of the cooling chamber is simply increased. That is, if the inside diameter of the cooling chamber is too large, the thickness of the surrounding bore pin becomes thin. If casting is performed by fitting a separate cylinder liner around the bore pin and casting molten metal around it, the cylinder liner is subjected to the molten metal pressure. In the case of casting a cylinder block without a rod, since the molten metal pressure directly acts on the thin portion of the bore pin, there arises a problem of deformation and breakage of the bore pin.
[0006]
Further, by enlarging the cooling chamber, the coolant is accumulated in the lower portion of the cooling chamber, while air remains in the upper portion of the cooling chamber, and uniform and sufficient cooling cannot be performed. For example, in the case of horizontal casting, the axis of the cylinder bore extends in the horizontal direction, but only the lower side of the cylinder bore is cooled by the cooling liquid, and only the air remains on the upper side without facing the cooling liquid. Uniform cooling is not possible in the entire circumferential direction.
[0007]
Furthermore, if the cooling chamber is made larger, the flow passage cross-sectional area of the cooling chamber itself is increased, so that the flow rate of the cooling liquid is lowered and instantaneous cooling becomes difficult.
[0008]
Therefore, the present invention provides a cylinder block casting bore pin that is not deformed or damaged by casting pressure, can be uniformly and sufficiently cooled in the entire circumferential direction of the bore pin, and can cast a cylinder block having no casting hole in the bore portion. The purpose is to provide.
[0009]
[Means for Solving the Problems]
To achieve the above object, the present invention includes a bore pin body, and a coolant pipe arranged in the bore pin body extending in the axial direction to form a cylinder bore in the outer peripheral surface of the distal end side of the bore pin body, the the coolant in the base end side of the bore pins body is introduced into the cooling liquid in the pipe also in the bore pin cylinder block casting for cooling at the tip side and discharged from the coolant pipe, the bore pin body, the outer peripheral surface of the has an outer member 2 having a hole portion 2a inside to form a cylinder bore, an inner member 3 to which the cooling liquid pipe 4 is placed inside with the fitted into the hole 2a of the outer member 2, the Cooling grooves 6, 7, 8, 9, 12, 13, 14 communicating with the coolant pipe 4 are formed on the outer peripheral surface of the inner member 3, and the cooling grooves 6, 7, 8, 9, 12, 13, 14 are each in the axial direction of the bore pins body A plurality of annular grooves 6, 7, 8 and 9 arranged in between consists of the axial grooves 12, 13, 14 Metropolitan for communicating each other to do the adjacent annular grooves 6, 7, 8, 9, the The annular groove 6 of one of the plurality of annular grooves 6, 7, 8, 9 is formed at the tip of the inner member 3 corresponding to the tip of the bore pin body, and each of the annular grooves 6, 7, 8 and 9, partition members 15, 16, which project from the outer peripheral surface of the inner member 3 defining the annular grooves 6, 7, 8, 9 to the outer member and extend in the axial direction of the bore pin main body, 17, 18, and the partition members 15, 16, 17, 18 are respectively connected to the annular grooves 6, 7, 8, in the direction in which the coolant flows in the circumferential direction of the annular grooves 6, 7, 8, 9. 9 and the downstream side of the connecting position of the axial grooves 12, 13, 14 in the annular grooves 6, 7, 8, 9 Te provides a bore pin cylinder block casting, characterized in that to regulate the flow of the coolant flowing along the circumferential direction of the annular grooves 6, 7, 8, 9.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The cylinder block casting bore pin 1 of the present invention will be described with reference to FIG. The bore pin 1 includes a bore pin main body including an outer member 2 and an inner member 3, and a coolant pipe 4 that is disposed inside the inner member 3 and extends in the axial direction of the bore pin main body.
[0011]
The outer member 2 has a long and substantially cylindrical shape, and a substantially cylindrical bottomed hole portion 2a for accommodating the inner member 3 is formed therein. The inner member 3 is fitted into the hole 2 a of the outer member 2, and the outer member 2 is screwed into the male screw 3 a formed on the proximal end side of the inner member 3. Is fixed to the inner member 3. An O-ring 19 is mounted between the inner peripheral surface of the outer member 2 and the outer peripheral surface of the inner member 3 to prevent coolant leakage. The front end side of the outer member 2 is disposed so as to protrude into the mold cavity, and the outer peripheral surface and end surface of the front end side protruding into the mold cavity are in direct contact with a molten metal such as an aluminum alloy to form a cylinder bore. The tip side has a slightly tapered draft shape. The front end portion of the inner member 3 fitted into the hole 2a of the outer member 2 has a columnar shape, and a cooling groove described later is formed on the outer peripheral surface thereof. A base end portion of the inner member 3 is fixed to a die die 5. The coolant pipe 4 has a double pipe structure composed of an inner pipe 4a for injecting coolant and an outer pipe 4b concentrically disposed with the inner pipe 4a, and the outer circumference of the inner pipe 4a and the inner circumference of the outer pipe 4b. A space between the surfaces serves as a coolant discharge passage (not shown).
[0012]
The inner member 3 is formed with a coolant pipe long hole 3 b for inserting the coolant pipe 4 so as to penetrate the inner member 3. The coolant piping long hole 3 b opens in the base end surface (not shown) of the inner member 3. The distal end portion of the coolant piping elongated hole 3b serves as a coolant passage guided by the inner tube 4a. The coolant piping long hole 3b is formed by drilling or the like in accordance with the outer diameters of the inner tube 4a and the outer tube 4b.
[0013]
First to fourth annular grooves 6, 7, 8, 9 serving as cooling grooves are formed on the outer peripheral surface of the front end portion of the inner member 3 so as to be separated from each other in the axial direction. These annular grooves can be easily formed by lathe processing or the like. An injection hole 10 communicating with the coolant hole 3b and the first annular groove 6 is formed extending in the radial direction of the inner member 3, and communicates with the fourth annular groove 9 and a coolant discharge passage (not shown). A discharge hole 11 is formed extending in the radial direction of the inner member 3. Further, as shown in FIG. 2, on the outer peripheral surface of the front end portion of the inner member 3, the first communication groove 12, the second annular groove 7 and the second annular groove 7 communicating with the first annular groove 6 and the second annular groove 7 are provided. A second communication groove 13 communicating with the three annular grooves 8 and a third communication groove 14 communicating with the third communication groove 8 and the fourth communication groove 9 are formed extending in the axial direction of the inner member 3. The 1st thru | or 3rd connection grooves 12, 13, and 14 as an axial direction groove | channel for communicating adjacent annular grooves mutually also comprise a part of cooling groove.
[0014]
As shown in FIG. 2, the first to fourth partition plates 15, 16, 17, as partition members for restricting the flow of the coolant in the first to fourth annular grooves 6, 7, 8, 9, 18 is provided. The first to fourth partition plates 15, 16, 17, and 18 are provided on the same straight line of the inner member 3 and adjacent to the injection hole 10 and the discharge hole 11 so as to divide the respective annular grooves. . These first to fourth partition plates 15, 16, 17, 18 are fixed to the inner member 3 by welding so as to be disposed in the respective annular grooves.
[0015]
In the above configuration, the coolant introduced from the inner tube 4 a to the tip of the coolant piping long hole 3 b is introduced into the first annular groove 6 from the injection hole 10. Since the first partition plate 15 exists in the vicinity of the injection hole 10, the coolant introduced into the first annular groove 6 does not flow upward but flows all downward in FIG. 2. Then, the coolant substantially goes around the inside of the first annular groove 6 and reaches the upper side of the first partition plate 15 in FIG. Since the first communication groove 12 is located in the vicinity of the first partition plate 15, the coolant then passes through the first communication groove 12 and is introduced into the second annular groove 7. Similarly, the coolant flows in the order of the second communication groove 13, the third annular groove 8, the third communication groove 14, and the fourth annular groove 9 to reach the discharge hole 11, and from the coolant discharge passage (not shown). Discharged. After the mold is opened, the die cast cast cylinder block is cut on the inner peripheral surface of the cylinder bore and subjected to surface treatment such as spraying or plating.
[0016]
The first to fourth annular grooves 6, 7, 8, and 9 are located close to the vicinity of the outer peripheral surface on the front end side of the outer member 2 even when compared with the outer tube 4 b, and a plurality of annular grooves are arranged in a row Therefore, the molten metal around the outer member 2 can be efficiently and uniformly cooled, and particularly in the case of a linerless cylinder block, the occurrence of a cast hole in the cylinder bore can be greatly suppressed. . In addition, since the cooling space is not a large space but a groove-like cooling passage, the flow rate of the coolant can be kept high. Furthermore, since the inner member 3 is inserted into the hole 2a inside the outer member 2, the inner member 3 can act as a deformation preventing member for the outer member 2 even when casting a linerless cylinder block. The deformation and breakage of the outer member 2 can be prevented.
[0017]
The cylinder block casting bore pin according to the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made within the scope described in the claims. For example, in the above embodiment, the separate partition plate is fixed to the inner member by welding, but when the annular groove is drilled, the partition plate is provided integrally with the inner member without processing a part thereof. Also good. In the above embodiment, the inner member is fixed to the die, but the bore pin may be pulled out of the cylinder block by connecting the inner member to the driving means. Further, the present invention is naturally applicable not only to casting of a linerless cylinder block but also to casting in which a liner or a fiber molded body is inserted into a bore pin and cast with a molten metal.
[0018]
【The invention's effect】
According to the cylinder block casting bore pin of the present invention, the coolant path can be positioned close to the outer peripheral surface of the outer member, and the molten metal can be efficiently cooled. In this case, it is possible to greatly suppress the occurrence of a cast hole in the cylinder bore. In addition, since the cooling space is not a large space but a groove-like cooling passage, the flow rate of the coolant can be kept high. Further, a high-pressure molten metal acts on the outer peripheral surface of the outer member at the time of casting, but the inner member is inserted into the hole inside the outer member, so that the inner member is also cast when linerless cylinder blocks are cast. Therefore, deformation and breakage of the outer member can be prevented. Furthermore, the cooling groove is formed by a plurality of annular grooves arranged in the axial direction of the bore pin main body so as to be spaced apart from each other and an axial groove for communicating adjacent annular grooves with each other. If they are centrally arranged, it is possible to intensively cool particularly the parts that require cooling. Further, since a plurality of annular grooves are formed, it is easy to adjust the cooling corresponding to the member to be cooled by changing the number and pitch of the grooves or changing the width and depth of the specific groove.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a bore block for casting a cylinder block according to an embodiment of the present invention.
FIG. 2 is a plan view of a distal end portion of an inner member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bore pin 2 Outer member 2a Hole 3 Inner member 4 Coolant piping 4a Inner tube 4b Outer tube 6 1st annular groove 7 2nd annular groove 8 3rd annular groove 9 4th annular groove 10 Injection hole 11 Discharge hole 12 1st Communication groove (axial groove)
13 Second communication groove (axial groove)
14 Third communication groove (Axial groove)
15, 16, 17, 18 Partition plate (partition member)

Claims (1)

Bore pin body ,
And a coolant pipe that extends in the axial direction is disposed in the bore pins body,
The bore pin to form a cylinder bore in the outer peripheral surface of the distal end side of the body, for cooling at the tip side coolant at the proximal end of the bore pins body is discharged from and introduced into the cooling liquid in the pipe also the cooling liquid pipe Te bore pin smell for the cylinder block casting,
The bore pin body, perforated outer member having a bore therein together with an outer peripheral surface to form the cylinder bore, and an inner member to which the cooling liquid pipe disposed therein with the inserted into the hole of the outer member A cooling groove communicating with the coolant pipe is formed on the outer peripheral surface of the inner member ;
The cooling groove has a plurality of annular grooves spaced apart to arranged each other in the axial direction of the bore pin body, Ri Do from the axial grooves to communicate with each other an annular groove each other adjacent, the plurality of annular grooves in the One of the annular grooves is formed at the tip of the inner member corresponding to the tip of the bore pin body,
In each of the annular grooves, a partition member that extends from the outer peripheral surface of the inner member that defines the annular groove to the outer member and extends in the axial direction of the bore pin body is provided.
Each of the partition members is provided immediately downstream of the connection position between the annular groove and the axial groove in the direction in which the coolant flows in the circumferential direction of the annular groove, and the circumference of the annular groove is within the annular groove. A bore block for casting a cylinder block, characterized by regulating a flow of coolant flowing along a direction .

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