JPH11347708A - Shielding member of cast-in pipe, and casting method using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing cost, and to prevent a circumferential surface inside a pipe from being damaged by providing an insertion part to be inserted from a pipe end and a core print forming part capable of forming a core print to be installed in a main die of the casting. SOLUTION: A shielding member 2 is mounted on an opening part 1a of a pipe stock 1 to be cast-in. The shielding member 2 is formed of a metallic hollow member, and comprises a press-fit part 3, a projecting part 4 and a tip part 5. A core print 6 as a core die is formed on an outer circumferential surface of the projecting part 4, the core print 6 is fixed in a main die 7 which is a sand mold, a molten metal is poured in a cavity 7a to effect the casting, and the pipe stock 1 is welded in the casting to manufacture a cast-in pipe. The casting obtained in a casting process is taken out of the main die, and shot-blasted to the outer circumferential surface of the casting as the grinding off treatment. The shielding member 2 is taken out of the casting to obtain the cast-in pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention simplifies the manufacturing process and reduces manufacturing costs by using it as a baseboard mounting portion for a cast-in pipe during casting and as a shield during blast processing such as shot blasting. Mounting of a shielding member on the cast-in pipe,
The present invention relates to a shielding member for a cast-in pipe that can be easily removed, and a casting method using the same.

[0002]

2. Description of the Related Art Conventionally, at the time of casting an exhaust manifold, an intake manifold, or the like, it has been practiced to mold an inner tube as an inner tube by molding, for example, Japanese Patent Application Laid-Open Nos. -276243 and JP-A-8-
No. 121158 is mentioned.

At the time of the casting, the cast product is fixed to a main mold using a baseboard so as not to move due to the pressure and buoyancy of the molten metal. Later, shot blasting was performed to remove sand and the like attached during casting.

[0004]

However, in such a conventional method for casting a cast-in-place pipe, a skirting board is attached at the time of casting, and is removed after casting to perform shot blasting. There is a problem that the manufacturing process becomes complicated and the manufacturing cost is deteriorated.

[0005] In addition, during the shot blasting process, there is also a problem that shot grains enter through the opening of the cast-in pipe and damage the inner peripheral surface of the pipe. Therefore, the present invention addresses such a problem and reduces the manufacturing cost and reduces the cost in the pipe by using it as a baseboard forming part of a cast-in pipe at the time of casting and as a shielding tool at the time of blast treatment such as shot blasting. An object of the present invention is to provide a shielding member for a cast-in pipe that can prevent the peripheral surface from being damaged, and a casting method using the same.

[0006]

In order to achieve the above object, in a pipe shielding member according to the first aspect, a stuffed pipe which is attached to an end of a stuffed pipe and shields the pipe end opening. Characterized by comprising an insertion portion inserted from the end of the pipe, and a skirting board forming portion capable of forming a skirting board to be installed on a casting main die.

According to such a configuration, the baseboard is formed by the baseboard forming section while the pipe end opening is shielded by the insertion section. In the pipe shielding member according to claim 2,
The insertion portion is a press-fit portion that is press-fitted into the inside of the pipe end and is in close contact with the inner peripheral surface of the pipe end.
It is a protrusion protruding outward from the pipe end.

According to this structure, the press-fitting portion is press-fitted into the cast-in pipe, thereby shielding the opening at the end of the pipe and forming a baseboard on the protruding portion so that it can be installed on the main mold. In the pipe shielding member according to claim 3, the insertion portion is formed with a screw that is screwed into the pipe, and is a threaded portion that is screwed to the end of the pipe.
It is a space formed inside the screwing portion and capable of forming the baseboard.

According to this configuration, by screwing the screwed portion to the cast-in pipe, the opening at the pipe end is shielded, and a baseboard is formed on the protruding portion so that it can be installed on the main mold. In the casting method according to the fourth aspect, the second aspect is provided.
A casting method for performing casting using a shielding member of a cast-in pipe according to the above, wherein the press-fitting portion is press-fitted into a raw tube and the shielding member is attached to the raw tube; A skirting board forming step of forming the skirting board, a casting step of placing the skirting board at a predetermined position of the main mold, casting and molding the base tube into a predetermined shape while casting, and an outer peripheral surface of the casting formed in the casting step And a blast treatment step of blast treatment.

[0010] According to this configuration, in the casting step, it is used as a core of the cast-in pipe, and in the polishing step, it is used as a shield for preventing the cleaning means from entering the pipe. In a casting method according to a fifth aspect, there is provided a casting method for performing casting using the shielding member of the stuffed pipe according to the third aspect, wherein a thread forming step of threading an end portion of the raw tube is provided. Screw the threaded part to the base tube,
An attaching step of attaching the shielding member to the base pipe, a skirting board forming step of forming a skirting board in the screwed portion internal space, and installing the skirting board at a predetermined position of a main mold, while casting the base pipe It is characterized by comprising a casting step of casting and molding into a predetermined shape, and a polishing step of polishing the outer peripheral surface of the casting formed in the casting step.

[0011] According to this configuration, in the casting process, the squeezing pipe is used as a baseboard mounting portion, and in the lapping process, the lapping means is used as a shield for preventing the rubbing means from entering the pipe. According to a sixth aspect of the present invention, in the casting method, the blasting process is shot blasting.

According to this configuration, shot grains used in shot blasting are prevented from entering the cast-in pipe.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the present invention.
It is a mimetic diagram showing a manufacturing process of an insert pipe in an embodiment. First, as shown in FIG. 1A, the shielding member 2 is attached to the opening 1a of the raw tube 1 to be cast-in (attaching step). The shielding member 2 is made of, for example, a hollow member made of metal, and includes a press-fit portion 3, a projecting portion 4, and a tip portion 5.

The press-fit portion 3 is a cylindrical portion having an outer diameter slightly smaller than the inner diameter of the raw tube 1, and when the press-fit portion 3 is pressed into the inner end of the raw tube 1, the outer peripheral surface and the inner peripheral surface of the raw tube 1 are in close contact. Then, the opening at the end of the raw tube 1 is shielded. The protruding portion 4 is a portion that protrudes from the press-fit portion 3 to the outside of the raw tube 1 when the shielding member 2 is attached to the raw tube 1, and has an outer diameter smaller than the outer diameter of the press-fit portion 3. The protruding portion 4 is formed of a material having a predetermined rigidity and heat resistance, since a baseboard 6 described later is formed on an outer peripheral surface thereof to be a core of the baseboard 6.

The distal end portion 5 is a portion located at the distal end when the shielding member 2 is press-fitted into the raw tube 1, and has a tapered shape tapering toward the distal end. With this taper, the shielding member 1 can be easily pressed into the opening of the raw tube 1. At the time of press-fitting the shielding member 2, it is possible to prevent the shielding member 2 from coming into contact with the molten metal in a casting step described later by pushing the shielding member 2 deeper than the end face of the raw tube 1.

Next, as shown in FIG.
Is formed on the outer peripheral surface of the baseboard as a core type (baseboard forming step). At this time, since the protrusion 4 becomes the core of the baseboard 6,
Fixing to the main mold can be ensured in a later casting step, and the raw tube 1 in the main mold cavity can be firmly restrained. Then, as shown in FIG. 3 (c), after fixing the baseboard 6 in the main mold 7 which is a sand mold, the cavity 7a
A molten metal is poured into the casting to form a casting, and the raw pipe 1 is welded into a casting to produce a stuffed pipe (casting step).

Next, as shown in FIG. 1D, the casting obtained in the casting step is taken out of the main mold, and the outer peripheral surface of the casting is subjected to shot blasting as a polishing treatment (a polishing step). The shot blasting is a process for the purpose of an abrasive action of colliding a shot made of accelerated steel grains or the like with the outer peripheral surface of the casting to remove sand adhered in the casting process. By performing the cleaning process with the part attached, the shot is prevented from entering the cast-in pipe and damaging the inner peripheral surface of the pipe. As a result, it is possible to maintain the accuracy of the inner peripheral surface in the cast-in pipe.

Finally, the shielding member 2 is removed from the casting to obtain a cast-in pipe as shown in FIG. At this time,
By pulling outward while gripping the projection 4, the shielding member 2 can be easily removed from the cast-in pipe. In the above series of steps, since the baseboard of the casting process is used as it is as a shield at the time of shot blasting, the process is simplified as compared with separately attaching and detaching the baseboard and the shield, and the manufacturing cost is reduced. Can be.

As described above, the first embodiment has been described.
The base tube 1 can be applied not only to a circular cross-section but also to a deformed one.
It is preferable to apply the inner peripheral surface according to the shape of the inner surface, or to apply the opening of the raw tube 1 in advance so as to correspond to the outer peripheral surface shape of the press-fitting portion 3. Drawing 2 is a mimetic diagram showing the manufacturing process of the insert pipe in a 2nd embodiment of the present invention. Note that the same members or portions as those in the first embodiment are denoted by the same reference numerals.

First, as shown in FIG. 1A, an inward flange is formed by punching out the vicinity of the center of the end face of the raw tube 1 and is used as a female screw 1b of the raw tube 1 (screw forming step). . Next, as shown in FIG. 1B, a shielding member 2 'is attached to the opening 1a of the blank tube 1 to be inserted (attaching step). The shielding member 2 ′ is made of, for example, a metal member, and includes a threaded portion 8 having a male screw 8 a and an internal space 9 as shown in FIG.

The male screw 8a is formed on the outer periphery of the screw portion 8, and is screwed to the female screw 1b of the raw tube 1. At the time of screwing, since the female screw 1b and the male screw 8a of the raw tube 1 are tightly screwed,
The opening at one end of the base tube can be reliably shielded. Although the female screw 8b is formed corresponding to the male screw 8a, this may be a flat inner wall. In addition, an inner space 9 is formed inside the shielding member 2 ', so that a baseboard 6 described later can be formed.

The flange 8c of the shielding member 2 'is bent outward and serves as a stopper for restricting further screwing of the shielding member 2'. Next, as shown in FIG. 3C, a core board 6 is formed in the internal space 9 as a core type (base board forming step). At this time, the female screw 8b
Since the baseboard 6 is formed in accordance with the shape of the main body and the shielding member 2 'and the baseboard 6 are securely fixed, the fixing to the main mold can be ensured in the casting step in the subsequent step, and the main mold cavity can be secured. The inner tube 1 can be firmly restrained.

Then, as shown in FIG. 2D, after the baseboard 6 is fixed in the main mold 7 which is a sand mold, a molten metal is poured into the cavity 7a to cast and mold the raw tube 1 into the casting. A stuffed pipe is manufactured by welding (casting process). Next, as shown in FIG. 3E, the casting obtained in the casting step is taken out of the main mold, and the outer peripheral surface of the casting is subjected to shot blasting as a polishing treatment (a polishing step). The shot blasting is a process for the purpose of blasting a shot made of accelerated steel grains or the like against the outer peripheral surface of the casting to remove sand adhered in the casting process. By performing the cleaning process with the opening attached to the opening 1a, it is possible to prevent the shot from entering the cast-in pipe and damaging the inner peripheral surface of the pipe. This allows
It is possible to maintain the accuracy of the inner peripheral surface in the cast-in pipe.

Finally, the shielding member 2 'is removed from the casting to obtain a cast-in pipe as shown in FIG. At this time, the shield member 2 'can be easily removed from the cast-in pipe by rotating the shield member 2' in a direction opposite to that at the time of screwing. In the above series of processes, the baseboard mounting part of the casting process is used as it is as a shield during shot blasting, so the process is simplified and the manufacturing cost is reduced compared to separately mounting and removing the baseboard mounting part and shield. Further, by simply rotating the shielding member 1, it can be attached to and detached from the cast-in pipe, and the workability can be improved.

As described above, the second embodiment has been described.
The present invention is not limited to this. For example, the polishing step may be a polishing process other than shot blasting. Also,
The raw pipe 1 can also be applied to a rectangular pipe as shown in FIG. 4. In this case, the female screw of the raw pipe 1 corresponds to the male screw of the shielding member 2 'in the screw forming step. Like pipe 1
The end face is machined into a circular cross section to form a female screw 1b.

Further, a female screw 1b formed on the end face of the raw tube 1 in the screw forming step is formed on the outer peripheral surface of the raw tube to be a male screw, and a female screw is formed on the inner peripheral surface of the screwing portion 8; May be screwed.

[0027]

According to the present invention, as described above, according to the pipe shielding member of the first aspect, since the shielding tool and the baseboard are formed as one member, the manufacturing cost is reduced. In addition, the inner peripheral surface of the pipe can be prevented from being damaged. According to the pipe shielding member according to claim 2,
By using it as a base of a cast-in-pipe at the time of casting and as a shield at the time of blasting processing such as shot blasting, it is possible to reduce manufacturing costs and prevent damage to the inner peripheral surface of the pipe.

According to the pipe shielding member of the third aspect, since the pipe is screwed to the cast-in pipe by the screw of the screw-in portion, the attachment / detachment to / from the cast-in pipe is facilitated, and the workability can be improved. . According to the casting method of the fourth aspect, since the baseboard used at the time of casting is used as it is as a shielding tool, the manufacturing process is simplified and the manufacturing cost is reduced, and the inner peripheral surface of the cast-in pipe is cleaned by the cleaning means. Since damage can be prevented, the accuracy of the inner peripheral surface of the cast-in pipe can be maintained.

According to the casting method of the fifth aspect, since the baseboard mounting portion used at the time of casting is used as a shield as it is, the manufacturing process is simplified, the manufacturing cost is reduced, and the inner peripheral surface of the cast-in pipe is reduced. Since it is possible to prevent the scrubbing means from being damaged, it is possible to maintain the accuracy of the inner peripheral surface of the cast-in pipe. According to the casting method according to the sixth aspect, it is possible to prevent the inner peripheral surface of the cast-in pipe from being damaged by shot particles at the time of shot blasting, which is a general blasting process.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a process of manufacturing a cast-in pipe according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a process of manufacturing a cast-in pipe according to a second embodiment of the present invention.

FIG. 3 is an enlarged sectional view showing a shielding member of a cast-in pipe according to a second embodiment of the present invention.

FIG. 4 is a two-side view of the case where the second embodiment of the present invention is applied to a cast-in pipe having a rectangular cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base tube 2, 2 '... Shielding member 3 ... Press-fit part 4 ... Projection part 8 ... Screw part 8a ... Male screw 8b ... Female screw 9 ... Internal space

Claims (6)

[Claims] A shielding member for a stuffed pipe attached to an end of a stuffed pipe for shielding an opening of the pipe end, comprising: an insertion part inserted from the pipe end; And a skirting board forming part capable of forming a skirting board. 2. The insertion portion is a press-fit portion that is press-fitted into the inside of the pipe end and is in close contact with the inner peripheral surface of the pipe end, and the skirting board forming portion is a protrusion that protrudes outward from the pipe end. The shielding member for a cast-in pipe according to claim 1, wherein: 3. The insertion part is formed with a screw that is screwed into the pipe, and is a screwed part that is screwed to the end of the pipe. The baseboard forming part is formed inside the screwed part. 2. The shielding member for a cast-in pipe according to claim 1, wherein the shielding member is a space in which the baseboard can be formed. 4. A casting method for performing casting using a shielding member of a cast-in pipe according to claim 2, wherein: a step of press-fitting the press-fitting portion into the raw tube and attaching the shielding member to the raw tube. A skirting board forming step of forming a skirting board with the protruding portion as a core; a casting step of installing the skirting board at a predetermined position of a main mold, and casting and molding the base tube into a predetermined shape while casting. A polishing treatment step of polishing the outer peripheral surface of the casting formed in the step. 5. A casting method for performing casting using a shield member of a cast-in pipe according to claim 3, wherein: a thread forming step of threading an end portion of the raw pipe; An attaching step of screwing to the pipe and attaching the shielding member to the raw pipe, a skirting board forming step of forming a skirting board in the interior space of the threaded portion, and installing the skirting board at a predetermined position of the main mold, A casting method, comprising: a casting step of casting and shaping a raw tube into a predetermined shape while being cast; and a lapping step of lapping an outer peripheral surface of a casting formed in the casting step. 6. The casting method according to claim 4, wherein the blast treatment step is a shot blast.