JPH09314226A - Tapered tube molding method and molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a tapered tube of small diameter by repeating the condition where the diameter of a cylindrical die for forming is reduced while a cylindrical tube is pressed in the axial direction to the cylindrical die for forming, and a condition where the diameter is enlarged. SOLUTION: A tube P is interposed between a jig 21 and a tapered cylindrical die 4. An advancing/retracting core 5 which is continuously provided on an output shaft of a second hydraulic cylinder 3 is reciprocated at the prescribed timing under the condition where the thrust in the axial direction is given to the tapered cylinder die 4 side. When the advancing/retracting core 5 is advanced, the diameter of the tapered cylindrical die 4 is increased by the taper fitting effect of the advancing/retracting core 5 to the tapered cylindrical die 4 and the effect of a first slit and a second slit. A part on a tip side of the cylindrical tube P is expanded. When the advancing/retracting core 5 is retracted, the diameter of the tapered cylindrical die 4 is reduced, and fitting of the cylindrical tube P to the tapered cylindrical die 4 becomes deeper. When advancement/retraction of the advancing/retracting core 5 is repeated, increase/ reduction of the diameter of the tapered cylindrical die 4 is repeated, and the tapered range is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a tapered tube and a molding apparatus, and more particularly to a method for molding a tapered tube having a small diameter and a small taper, and an apparatus for carrying out the method.

[0002]

2. Description of the Related Art Usually, a tapered tube is manufactured by bending a plate material cut into a fan shape into a tapered cylindrical shape by roll bending. This method can manufacture a tapered cylinder having a large diameter, but it is difficult to manufacture a tapered tube having a small diameter. In the case of roll forming, when bending the plate material as a work into a taper tube shape, it is necessary to arrange a bending roller inside and outside the taper tube as a product, and these bending rollers. The diameter of must have sufficient rigidity for the bending stress acting during the bending process.

For this reason, the diameter of the bending roller is inevitably increased, and the diameter of the product cannot be reduced so much.

[0004]

The invention of claim 1 is made in view of the above point, and a tapered pipe having a small diameter can be easily manufactured by molding the tapered pipe from a cylindrical pipe. The task is to reduce the force required for molding. The invention of claim 2 is
It is an object of the present invention to provide an apparatus capable of smoothly carrying out the method of claim 1 which solves the above-mentioned problems.

The inventions set forth in claims 3 and 4 aim to obtain the respective effects described in the section of effects in addition to solving the above problems.

[0006]

[Means for Solving the Problems] The solution means of the invention of claim 1 taken in order to solve the above-mentioned problems is as follows: "The small-diameter side end of a cylindrical molding die whose outer peripheral surface is a tapered surface that matches the product taper. A step of facing one end of the cylindrical pipe to the portion, and a state in which the diameter of the molding cylinder is reduced and a state in which the cylindrical pipe is expanded with the cylindrical pipe being pressed in the axial direction with respect to the molding cylinder. It has a repeating process ”.

The above solution works as follows. Since the outer peripheral surface of the molding pipe is a tapered surface that matches the product taper, when the cylindrical pipe is axially pressed at the small diameter side end of the tip of the molding pipe, the cylindrical pipe The tip portion is expanded in a tapered shape in accordance with the applied pressure. When the diameter of the molding cylinder is expanded in this state, it is further expanded into a tapered shape, and then the diameter of the molding cylinder is reduced (by its own operation or the thrust of the work),
Depending on the degree of reduction, the tip end side of the cylindrical tube is fitted further deeply from the tip end portion of the molding cylinder. After that, when the diameter of the molding cylinder is increased, the range molded in a taper shape becomes longer. After that, when the cylindrical pipe is repeatedly pressed in the axial direction with respect to the molding cylinder in a state where the diameter of the molding cylinder is reduced and when the diameter is expanded, the cylindrical pipe is molded into a tapered shape. The range thus formed gradually becomes longer, and finally, the desired range is formed into a tapered tube.

When molding the tapered pipe, the fitting portion between the molding cylinder and the cylindrical pipe is gradually expanded to finally form a tapered pipe. Therefore, one step for expanding the tapered pipe is performed. The required power of becomes small. The invention of claim 2 is an apparatus for carrying out the method of the invention of claim 1, "a pipe holding part for holding one end of a cylindrical pipe, and a thrust applying means for pushing the pipe holding part in an axial direction, A molding cylinder having a tapered surface provided coaxially with the pipe holding section at a position facing the pipe holding section and having a diameter decreasing toward the pipe holding section, and an outer periphery of the molding tube. A diameter expanding means for forcibly deforming the diameter of the surface from the contracted state to the expanded state, and a diameter expanding control means for intermittently operating the diameter expanding means are provided, and the molding cylinder has a diameter expanding external force when applied. In the expanded state, when the external force for expanding the diameter disappears, a cylindrical type made of an elastic material that elastically returns to the small diameter state ”is used.
That is.

In this structure, when one end of the cylindrical pipe is held by the pipe holding portion and the cylindrical pipe is pushed out in the axial direction by the thrust applying means, a molding cylinder is formed at a position facing the pipe holding means. The tip end portion of the cylindrical pipe is forcibly fitted onto the small diameter portion at the tip end thereof coaxially. Thereafter, the diameter expanding means intermittently executes the diameter expanding operation under the control of the diameter expanding control means. As a result, when the diameter expanding means is operating, the molding cylinder is in a diameter expanding state, and when the diameter expanding means is deactivated thereafter, the molding cylinder is reduced in diameter. The diameter expansion-diameter reduction is repeated while pressurizing the cylindrical pipe to the molding cylinder.
The method of the invention is carried out.

According to a third aspect of the present invention, in the second aspect of the invention, the molding cylinder, the diameter expanding means, and the diameter expanding control means for intermittently operating the diameter expanding means are limited. The inner cylinder surface and the outer peripheral surface are tapered surfaces and the tapered cylinder shape is provided with a plurality of slits which are open only at one end. The diameter expanding means is tapered into the tapered cylinder shape. As described above, the advancing / retreating core is inserted from the large diameter side and is supported so as to be reciprocally movable in the axial direction. Was used as a means to control.

With this means for solving the problem, when the advancing and retracting core is advanced, the taper cylinder type is provided with a plurality of slits which are opened only at one end, so that The width of this slit is expanded by the taper fitting action of, and the diameter of the taper cylinder is expanded as a whole. When the advancing / retreating core retreats, the width of the slit is reduced by the elastic restoring force, and the diameter of the taper cylinder is reduced as a whole. In this manner, by driving the advancing / retreating core to advance / retreat, the taper tubular mold is brought into the expanded diameter state and the reduced diameter state.

That is, it is possible to repeat the diameter expansion-diameter reduction by a structure in which the advancing / retreating core is taper-fitted to the taper cylinder type and the advancing / retreating core is driven forward / backward. In addition, as the above-mentioned “provided with a plurality of slits opened only at one end”, the first slit opened only at the large diameter side end of the taper tubular type and the first slit opened only at the small diameter side end It is preferable that the first slits and the second slits are alternately arranged in the circumferential direction ", or in addition to the above configuration," the first slit and the second slit are alternately arranged ". 1
The third slit which is not opened at any end may be interposed between the slit and the second slit in the circumferential direction.

According to the invention of claim 4, claim 2
In the invention, "The molding cylindrical die is composed of a plurality of arcuate cross-sections that are vertically divided, and the inner peripheral surface and the outer peripheral surface are tapered surfaces and are supported by a fixed wall so as to be freely expanded / contracted. A taper tube type is used, and the diameter expanding means is an advancing / retreating core which is inserted from the large diameter side so as to be taper-fitted in the taper tube type and is supported so as to be capable of reciprocating in the axial direction. ,
The means for reciprocating the advancing / retreating core between the advancing state and the retreating state and controlling the timing of the reciprocating driving "operates similarly to the invention of claim 3. In addition,
According to the invention of claim 4, the diameter reduction force of the taper cylinder type is forcibly reduced mainly by the thrust force applied from the cylindrical pipe as the work, not by the elastic restoring force of itself. Become.

[0014]

According to the first aspect of the present invention, since the fitting portion with the cylindrical pipe is gradually expanded to finally form a tapered pipe, a tapered pipe having a small diameter can be formed and the expanded pipe is tapered. The power required for one step to do this is reduced. Therefore, there is an advantage that the processing force for forming the tapered tube can be reduced. According to a second aspect of the invention, the method of the first aspect of the invention is reliably carried out by repeating the expansion / contraction diameter while pressurizing the cylindrical pipe to the molding cylinder.

According to the third aspect of the present invention, since the advancing / retreating core is taper-fitted to the taper cylinder type and the advancing / retreating core is driven forward / backward, the expansion / contraction can be repeated. The configuration for repeating can be simplified. Therefore, the entire device can be downsized. Further, since the tapered cylindrical type has a plurality of slits extending in the axial direction, the diameter expansion-
Sufficient rigidity can be secured under the condition that the diameter can be reduced, and the supporting condition of the taper cylinder type is stable.

According to a fourth aspect of the present invention, since the plurality of arcuate cross-section bodies forming the taper cylinder type are separated from each other, the acting force for expanding the diameter of the taper cylinder type is different from that of the third aspect of the invention. Is less.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In the embodiment shown in FIGS. 1 to 4, a first hydraulic cylinder as a thrust applying means is provided on one of the upper surfaces of the base (1).
(2) is placed in a horizontal position, and this first hydraulic cylinder (2)
Hydraulic cylinder forming a diameter expansion control means on the opposite side of the
(3) is installed in a horizontal position.

The output shafts of the first hydraulic cylinder (2) and the second hydraulic cylinder (3) are arranged so as to face each other on a coaxial line.
A jig (21) as a pipe holding part is attached to the tip of the output shaft of one of the first hydraulic cylinders (2), and this jig (21) is a cylinder on a holding shaft part (22) of small diameter on the tip side. There is such a relationship that one end of the pipe (P) is externally fitted and the end portion of the cylindrical pipe (P) abuts on the flange portion protruding from the base end portion of the holding shaft portion (22).

On the opposite side of the jig (21), there is provided a taper cylinder (4) as a molding cylinder. This taper tube type (4)
Is attached in a cantilevered state by the side plate (11) protruding from the upper surface of the base (1), and the small diameter end (41) at the tip thereof is attached.
Are coaxially opposed to the jig (21). As shown in the perspective view of FIG. 2, the tapered cylindrical type (4) has an inner peripheral surface and an outer peripheral surface formed into a tapered surface. In this example,
Both tapered surfaces are set to have the same taper. Then, a certain range of the end portion on the large diameter side becomes the cylindrical portion (42), and the brim portion (43) projects from the end portion. Further, the taper cylinder type (4) has a plurality of taper cylinder types which are opened from the middle to the end surface of the collar portion (43) and are opened only at the large-diameter side end portions.
Slits (S ₁ ) and a plurality of second slits (S ₂ ) that are open only from the middle to the small diameter side end are alternately arranged in the circumferential direction.

As shown in FIG. 1, the flange portion (43) of the taper cylinder type (4) is held by a holding plate (12) attached to the inner surface of the side plate (11), and the taper cylinder type (4) ) Projects to the jig (21) side in a cantilevered state. The holding plate (12) has a relationship in which only the flange portion (43) is held in a loosely fitted state and the end surface of the flange portion (43) is slidably pressed against the inner surface of the side plate (11). In the cantilevered state, the diameter of the collar portion (43) is held in the restraining plate (12) so that it can be enlarged.

Also, a second plate attached to the outside of the side plate (11).
The output shaft of the hydraulic cylinder (3) is provided with an advancing / retreating core (5) as the diameter expanding means, and the advancing / retreating core (5) penetrates the side plate (11) to form the taper cylinder type (4). ) It is projected coaxially with this. The shape of the outer peripheral surface of the advancing / retreating core (5) matches the shape of the inner peripheral surface of the tapered cylindrical die (4), and is composed of a tapered surface and a cylindrical surface. In this example, a low friction coefficient layer (44) such as a fluororesin coating layer (44) is formed on the inner peripheral surface of the taper cylinder type (4) in order to reduce sliding friction with the outer peripheral surface of the advancing / retreating core (5). Is forming. A similar low friction coefficient layer is also formed on the inner peripheral surface of the through hole of the advancing / retreating core (5) in the side plate (11).

Further, the operation of the second hydraulic cylinder (3) is controlled by the control device (C), and when the control device (C) is put into an operating state, the second hydraulic cylinder (3) is The output shaft of is reciprocally driven with a constant stroke. This second hydraulic cylinder (3) and the control device
(C) serves as the diameter expansion control means. [Molding Practice] The actual practice of molding a tapered cylinder from a cylindrical pipe (P) using the apparatus of this embodiment will be described.

One end of the cylindrical pipe (P) is externally fitted to the holding shaft portion (22) of the jig (21) of the above-mentioned device, and the other end is a tapered tubular type.
The cylindrical pipe is fitted to the small diameter end (41) of (4).
(P) is interposed between the jig (21) and the taper cylinder type (4).
After that, the first hydraulic cylinder (2) is brought into an output state and the control device (C) is brought into an operating state.

As a result, the cylindrical pipe (P) has a tapered tubular shape.
In the state where the axial thrust force is applied to the (4) side, the advancing and retracting core (5) connected to the output shaft of the second hydraulic cylinder (3) is reciprocally driven at a predetermined timing. When the advance / retreat core (5) advances, the taper fitting action of the advance / retreat core (5) and the taper tube type (4) and the above-mentioned first slit (S ₁ ) and second slit (S ₂ ). As a result, the diameter of the taper cylinder type (4) becomes large as shown in the sectional view of FIG. As a result, the diameter of a part of the distal end side of the cylindrical pipe (P) fitted on the distal end of the tapered tubular type (4) is increased. After that, when the advancing / retreating core (5) retracts, the elastic return force of the taper cylinder type (4) and the thrust of the cylindrical pipe (P) given by the first hydraulic cylinder (2) cause the taper as shown in FIG. Although the diameter of the cylindrical pipe (4) is reduced, the thrust from the first hydraulic cylinder (2) acts on the cylindrical pipe (P), so that the cylindrical pipe (P)
And the taper cylinder type (4) are deeply fitted.

Then, with the thrust applied to the cylindrical pipe (P) by the first hydraulic cylinder (2), the advancing and retracting core is moved.
By repeating the forward / backward movement of (5), the diameter of the taper cylinder type (4) is repeatedly expanded and contracted, and the tapered range of the cylindrical pipe (P) is gradually expanded. . At this time, the acting force required to expand the diameter of a part of the cylindrical pipe (P) is transferred from the first hydraulic cylinder (2) and the second hydraulic cylinder (3) to the taper cylinder type (4) and the jig (21). It should work. By repeating the above steps, finally, a tapered tube (M) as shown by the imaginary line in Fig. 1 is obtained. In some cases, the cylindrical portion may remain, but in this case, the cylindrical portion may be finally cut off.

In the above embodiment, the taper cylinder type is used.
Although only the first slit (S ₁ ) and the second slit (S ₂ ) are formed in (4), in addition to this, the third slit (S ₃ ) Is the first slit (S
It may be configured to be interposed between ₁ ) and the second slit (S ₂ ). In addition, in this embodiment, by providing the first slit (S ₁ ) and the second slit (S ₂ ) and the like,
The diameter of the tapered cylinder type (4) is expanded by the elastic material made of metal,
Although it is possible to reduce the diameter, it is possible to enlarge and reduce the diameter by using a method in which the slit is formed in a spiral shape or a configuration in which the taper cylinder type (4) is vertically divided into a plurality as shown in FIG. Good. Even in the case of FIG. 6, as shown in FIG.
Holding the collar (43) so that it can slide in the radial direction,
Acts similarly.

Further, in this embodiment, the cylindrical pipe
Although the first hydraulic cylinder (2) was used to push (P) into the taper cylinder type (4) side, instead of this first hydraulic cylinder (2), a feed screw mechanism rotated by a rotary drive source is used. A jig (21) may be attached to the tip of the output shaft. By doing so, the cylindrical pipe (P) held by the jig (21) is pushed out to the taper tube type (4) side and the cylindrical pipe (P)
Is rotated in the circumferential direction of the cross section, the finish of the tapered pipe is improved. Especially, the tapered cylinder type with the above slit
Even if (4) is used, no trace of this slit remains.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a perspective view of the taper cylinder type (4).

FIG. 3 is a sectional view of the taper tube type (4) in an enlarged state in the taper pipe molding process.

FIG. 4 is a cross-sectional view of the taper tube mold (4) contracted in the taper pipe molding process.

FIG. 5 is a plan view of another form of the tapered tubular type (4).

FIG. 6 is a perspective view of another form of the tapered tubular type (4).

[Explanation of symbols]

 (4) ・ ・ ・ ・ Taper tube type (21) ・ ・ ・ ・ Jig (P) ・ ・ ・ ・ Cylinder pipe (2) ・ ・ ・ ・ First hydraulic cylinder (3) ・ ・ ・ ・ Second hydraulic cylinder

Claims (4)

[Claims] 1. A step of causing one end of a cylindrical pipe to face a small-diameter side end portion of a molding cylindrical die whose outer peripheral surface is a tapered surface that matches a product taper, and the cylindrical pipe being axial with respect to the molding cylindrical die. A method of molding a taper tube, comprising the step of repeating a state in which the diameter of the molding cylinder is reduced and a state in which the diameter is enlarged in a state of being pressurized in a direction. 2. A pipe holding portion for holding one end of a cylindrical pipe, a thrust applying means for pushing the pipe holding portion in an axial direction, and a pipe holding portion provided coaxially with the pipe holding portion at a position facing the pipe holding portion. A molding cylinder having a tapered surface whose diameter decreases toward the pipe holding portion side;
The molding cylinder comprises a diameter expansion means for forcibly deforming the diameter of the outer peripheral surface of the molding cylinder from a reduced state to an expansion state, and a diameter expansion control means for intermittently operating the diameter expansion means.
A molding device for a cylindrical pipe made of an elastic material, which is in a diameter expanded state when an external diameter expansion force is applied and elastically returns to a small diameter state when the external diameter expansion force disappears. 3. The molding cylinder mold is a taper cylinder mold having a plurality of slits whose inner peripheral surface and outer peripheral surface are tapered surfaces and is opened only at one end, and the diameter expanding means is the taper cylinder. An advance / retreat core inserted from the large diameter side so as to be taper-fitted in the mold and supported so as to be reciprocally movable in the axial direction,
The taper pipe molding apparatus according to claim 2, wherein the diameter expansion control means is means for reciprocating the advancing / retreating core between an advanced state and a retracted state and controlling the timing of the reciprocating drive. 4. The molding cylinder is a taper cylinder having an arcuate cross-section body having an inner peripheral surface and an outer peripheral surface that are tapered surfaces and is vertically divided into a plurality of parts. The advancing / retreating core is inserted from the large diameter side so as to be taper-fitted to and is supported so as to be reciprocally movable in the axial direction, and the diameter expansion control means reciprocally drives the advancing / retreating core between the advanced state and the retracted state. The taper pipe molding device according to claim 2, wherein the taper pipe molding device is a means for controlling the timing of the reciprocating drive.