JPH05192760A - Manufacture of sliding block - Google Patents

Abstract

PURPOSE:To well adhere the block body with the graphite rod operating the solid lubrication and to precisely arrange the position of graphite rod in the block body. CONSTITUTION:After a graphite rod 13 is fixedly supported with a core 35 by embedding a part of the graphite rod at the core 35, a casting mold 21 is formed by combining a cope 23, a drag 28 and the core 35. Next, the molten metal is poured in a cavity 40 of the casting mold 21, the remainder of the graphite rod 13 is cost in with the molten metal because the remainder is projected in the cavity. In this time, the adhesion is made well by diffusing the graphite of the graphite rod 13 in the molten metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a sliding block in which a block body is cast around a graphite body for performing a solid lubricating action.

[0002]

2. Description of the Related Art Generally, in a mechanical device or the like, there is a place where members slide with each other, for example, a place where a slide bearing or a guide bush is installed. In order to reduce friction and wear between members at such places. It has been practiced to embed a graphite body having a solid lubricating function in a member.

Conventionally, as a sliding block in which such a graphite body is embedded, for example, one described in JP-A-64-87056 is known. This one is
A block body made of cast iron is embedded with a plurality of graphite bodies having a solid lubricating action. In order to manufacture this, first, a plurality of graphite bodies are embedded in a model made of foamed polyethylene or the like that burns when it contacts the cast iron molten metal in the same shape as the sliding block, and then the graphite bodies are embedded. The casting mold is filled around the model with a molding sand. Next, molten cast iron is poured into the mold to burn the model to form a cavity in the mold, and the cavity is filled with the molten cast iron. As a result, the graphite body is cast around by the molten cast iron. Then, this molten cast iron is cooled and solidified to form a sliding block. Then, the sliding block is machined if necessary.

[0004]

However, in the manufacturing method as described above, since the burning dust generated when the model burns adheres to the periphery of the graphite body, the graphite body and the molten metal (metal) cooled and solidified are cooled. Adherence is insufficient, and as a result,
If the manufactured sliding block is subjected to vibration or the like for a long time, the graphite body may come off from the sliding block. Moreover, when the model burns, the graphite body is insufficiently supported due to a large amount of gas and molten metal pressure, so the graphite body moves and is moved by the molten metal, and the placement position is distorted or it falls off and the sliding block is defective. There is also the problem of

It is an object of the present invention to provide a manufacturing method capable of achieving good adhesion between a block body and a graphite body, and moreover arranging the graphite body at a precise position.

[0006]

The object is to combine a plurality of mold segments in which a plurality of mold segments each having a part of a plurality of graphite bodies embedded therein, and a combination of the plurality of mold segments. , A step of molding a mold having a cavity in which the remainder of the graphite body projects, a step of pouring a molten metal into the cavity of the mold and surrounding the remainder of the graphite body with the melt, and cooling and solidifying the melt And a step of producing a sliding block composed of the block body and a graphite body cast around the block body.

[0007]

First, a plurality of mold segments constituting the mold are formed. At this time, a part of the plurality of graphite bodies is embedded in at least one of the mold segments. As a result, the rest of these graphite bodies project from the surface of the mold segment. Next, a mold is molded by combining these plurality of mold segments. Here, a cavity into which the molten metal is poured is formed inside the thus-formed mold, and the remaining portion of each graphite body projects into this cavity. Next, molten metal is poured into the cavity of the mold to fill the cavity with the molten metal, and at this time, the remainder of the graphite body protruding from the mold segment is surrounded by the molten metal. When pouring,
The molten metal comes into contact with the graphite body and gives an external force, but since each graphite body is partially embedded in the mold segment, it does not slip off or come off and maintain a predetermined position. Next, the molten metal filling the cavity is cooled and solidified to form a block body. As a result, a sliding block composed of the block body and the graphite body cast around the block body is manufactured. As described above, in the present invention, since no burnt residue is generated during pouring, the surface of the graphite body is in direct contact with the molten metal, and as a result, the graphite is slightly diffused in the molten metal and blocks the graphite body and the block. Strong adhesion to the body. Moreover, since each graphite body is firmly supported by the mold segment as described above, it is not poured into the molten metal,
Precisely placed in place in the sliding block.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 denotes a guide bush as a sliding block used in a press die or the like. The guide bush 10 includes a block main body 11 made of a metal such as cast iron or a copper alloy, and a block main body 11 inside the block main body 11. A columnar graphite rod 13 as a plurality of embedded graphite bodies,
It consists of The block body 11 has a cylindrical portion 12, and an inner peripheral surface 15 of the cylindrical portion 12 serves as a sliding surface that is in sliding contact with a guide pin, for example. Cylindrical portion 12 of the block body 11
The graphite rods 13 extending in the radial direction are embedded in the inside by casting, and a part of these graphite rods 13, here the radial inner end, is the inner peripheral surface 15 (sliding surface) of the cylindrical portion 12. Exposed to the outside and its radial outer end ends midway in the cylindrical portion 12. Here, each graphite rod 13 is composed of a large number of graphite particles of 150 mesh or less bonded by a binder composed of phenol resin, coal tar pitch or the like with a weight ratio of 15% or less. Min is a graphite rod
Before 13 is cast into the block body 11, it is graphitized. Here, such graphitization of carbon content is carried out, for example, by first loading the molded graphite rod 13 into a firing furnace and then heating it to about 700 ° C to 1100 ° C in an oxygen-free atmosphere so that the graphite rod 13 To carbonize the carbon content, and then to cool the inside of the furnace to about 370 ℃ ~ 400 ℃ to prevent oxidation, and then cooled to the atmosphere, then the graphite rod 13 is carried into a graphite furnace, in an oxygen-free atmosphere. It is carried out by heating to 2500 ° C or higher, for example 2500 ° C to 3000 ° C, to graphitize the carbonized carbon, and then to cool the inside of the furnace to 370 ° C to 400 ° C to prevent oxidation and then to cool it to the atmosphere. ..

In manufacturing the guide bush 10 as described above, a mold 21 as shown in FIG. 2 is molded. To mold such a mold 21, first, the upper frame 22 is not shown. After placing on the board, a wooden pattern (not shown) of a predetermined shape is stored in the upper frame 22, and then the upper frame 22
The mold is filled with casting sand such as self-hardening sand and carbon dioxide sand to be tamped, and the wooden mold is removed from the casting sand. As a result, the upper mold 23 as a mold segment is molded. When forming the upper mold 23, the sprue 24 and the riser 25 are simultaneously formed. The lower frame 27 is filled with the molding sand as described above and is tampered with to mold the lower mold 28 as a mold segment. A ring groove 29 and a plurality of radial grooves 30 extending radially inward from the ring groove 29 are formed on the upper surface of the lower mold 28. Reference numeral 35 is a core as a mold segment in the shape of a hollow cylinder, and a part of a plurality of radially extending graphite rods 13, that is, a radially inner end is embedded in the outer periphery of the core 35. As a result, the rest of these graphite rods 13 project from the outer periphery of the core 35. Here, the burial depth D of the graphite rod 13 in the core 35 is preferably 3 mm or more. The reason is,
If the burial depth D is less than 3 mm, the graphite rod 13 will cause the core 35 to move when the molten metal flows into the cavity, which will be described later.
This is because there is a risk of getting out of it. Then, the core 35 in which such a graphite rod 13 is embedded, the remaining side of the graphite rod 13 is inserted into the inner surface of a mold (not shown) of the split mold, and in this state as described above in the mold. It was filled with molding sand and tamped, and then the mold was removed from the core 35, or the molding sand as described above was filled and tamped in a mold having a plurality of protrusions formed on the inner surface. After that, the mold is removed from the core 35, and then a part of the graphite rod 13 is inserted into each hole formed on the outer periphery of the core 35 by the projection, thereby molding.

Next, the three mold segments as described above, that is, the upper mold 23, the lower mold 28, and the core 35 are combined to form the mold 21.
A cavity 40 having the same shape as the guide bush 10 is formed in the mold 21 thus molded. Here, the remaining part of the graphite rod 13 partially embedded in the core 35 projects into the cavity 40. The upper ends of the ring groove 29 and the radial groove 30 are closed by the upper die 23 to form a runner 41 communicating with the lower end of the cavity 40. Next, a molten metal of metal, here cast iron, is poured from the spout 24 and filled into the cavity 40 through the runner 41. Then, when the cavity 40 is filled with the molten metal, the remaining portion of the graphite rod 13 protruding from the core 35 is cast by the molten metal. At the time of this pouring, the molten metal is poured into the cavity 40 from its lower end, so that the molten metal does not directly fall on the rest of the graphite rod 13, and as a result, melting loss of the graphite rod 13 is suppressed. At this time, the molten metal comes into contact with the graphite rod 13 to give an external force,
Since each graphite rod 13 is partially embedded in the core 35, it does not slip or come off, and maintains a predetermined position. Further, since the graphite rod 13 is surrounded by the molten metal, it is heated to almost the same temperature as the molten metal, but since the carbon content in the binder of these graphite rods 13 is graphitized as described above, Even if the graphite rod 13 is heated to a high temperature, the carbon content (graphite) in the binder does not burn, and as a result, the graphite rod 13 is cast in the molten metal without burning.

When the cavity 40 is thus filled with the molten metal, the pouring is stopped and the molten metal in the cavity 40 is cooled and solidified to form the block body 11. As a result, the guide bush 10 in which the graphite rod 13 is cast in the block body 11 is formed. Next, guide bush 10
After removing from the mold 21, the molding sand is removed from the guide bush 10 by shot blasting.At this time, since the hardness of the graphite rod 13 is considerably smaller than the hardness of the block body 11, the graphite rod 13 is too shaved by shot blasting. Make sure that it is not dented from the inner peripheral surface 15 of the guide bush 10. Next, if necessary, the guide bush 10 is machined, for example, the inner peripheral surface 15 and the outer peripheral surface are ground, and a part of the graphite rod 13, here, the radially inner end is formed on the inner peripheral surface 15 of the guide bush 10. Exposed to (sliding surface). As described above, in this embodiment, since no burned residue is generated during pouring, the surface of the graphite rod 13 and the molten metal come into direct contact with each other, and as a result, the graphite is slightly diffused in the molten metal and the graphite rod The bond between 13 and the block body 11 becomes strong. Further, since each graphite rod 13 is firmly supported by the core 35 as described above, it is not poured into the molten metal and is accurately arranged at a predetermined position in the guide bush 10. The surface roughness of the outer surface of the graphite rod 13 described above is preferably rough. The reason is that the contact area between the molten metal and the graphite rod 13 increases, and moreover, graphite diffusion is easily performed,
This is because the adhesion between the graphite rod 13 and the block body 11 is improved.

In the above-mentioned embodiment, since the sliding block is the guide bush 10, it has a cylindrical shape with a flange. However, in the present invention, the sliding block may be a plate-shaped wear plate. Good. Further, in the above-mentioned embodiment, a cylindrical rod was used as the graphite rod 13, but in the present invention, various shapes such as a prismatic column can be used, and the sliding block is penetrated. It may be one. Further, in the present invention, a part of the graphite body may be embedded in the upper and lower molds 23, 28.

[0013]

As described above, according to the present invention, the adhesion between the block body and the graphite body can be made good and the graphite body can be arranged accurately.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is a sectional view of a mold for manufacturing a sliding block.

[Explanation of symbols]

 10 ... Sliding block 11 ... Block body 13 ... Graphite body 21 ... Mold 23, 28, 35 ... Mold segment 40 ... Cavity

Claims (1)

[Claims] 1. A step of forming a plurality of mold segments in which a part of a plurality of graphite bodies is embedded in at least one of them, and a combination of the plurality of mold segments, the remainder of the graphite body protruding inside. A mold having a cavity with a mold, a process of pouring a molten metal into the mold cavity and surrounding the rest of the graphite body with the melt, and cooling and solidifying the melt to form a block body. And a step of manufacturing a sliding block composed of a graphite body cast around the block body.