JPH052932U - U-shaped tube mold - Google Patents

Abstract

(57) [Summary] [Purpose] A U-shaped pipe molding die that can efficiently produce U-shaped pipes (J-shaped pipes) with straight pipes of different lengths, and that can also have a sufficiently large arc portion diameter. I will provide a. [Structure] The abutting surfaces of the rotary back molds 15a, 15b are arranged at a substantially equidistant point Y from the U-shaped pipe ends X, Z along an axis L of the U-shaped pipe P and an inner center point of the arc portion P _2. Position it on the line connecting with A '.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a U-shaped tube molding die, and more particularly, to a die for integrally molding a U-shaped tube (J-shaped tube) having different straight tube portions by plastic injection molding.

[0002]

[Prior Art]

 As a mold for integrally molding a U-shaped tube by injection molding of plastic, a fixed mold having a U-shaped concave portion corresponding to the outer shape of the U-shaped tube therein, as described in, for example, JP-A-61-248716. And a movable die having a pair of mouth dies corresponding to the straight pipe portion of the U-shaped pipe and a pair of rotary inner dies corresponding to the circular arc portion of the U-shaped pipe are known.

In such a U-shaped tube molding die, when the movable die is removed from the fixed die after molding, the mouth die is linearly withdrawn, and at the same time, the turning inner die is connected to the straight pipe portion of the U-shaped pipe. It is constructed so that it can be pulled out after being rotated to a position where it does not interfere.

[0004]

[Problems to be solved by the device]

 However, as a U-shaped pipe often used for a water distribution pipe joint, as shown in, for example, Japanese Utility Model Laid-Open No. 64-2174, a straight pipe portion having a different length (J-shaped pipe) is often used. .. On the other hand, in the conventional U-shaped tube molding die, since the dividing position of the turning inner die is divided at the bottom of the U-shaped tube, that is, at an angle of about 90 degrees, the length of the straight tube portion of the U-shaped tube is increased. However, if the inner diameters of the ends of the U-shaped pipes are the same and the drafts of both calibers and the movable die are the same, the outer diameter of the turning inner die with the longer straight pipe portion becomes smaller. , A step is generated at each of the turning inner contact portions.

In order to eliminate the above-mentioned step, the outer diameters of the contact portions of the respective turning inner dies are made the same, and the diameter of the shorter straight pipe portion and the draft of the turning inner die are appropriately set. Since the diameter of the longer straight pipe part and the draft of the rotary back mold are smaller, the mold release property is deteriorated, the mold release balance of both pipe parts is deteriorated, and it causes the mold release defect trouble during production. Cheap. On the other hand, if the diameter of the longer straight pipe part and the turning back die draft are set sufficiently, the outer diameter of the turning back die becomes small, so the inner diameter of the arc portion of the U-shaped pipe obtained becomes too small and the drainage The efficiency will be reduced.

Therefore, the present invention provides a U-shaped tube molding die capable of efficiently producing a U-shaped tube (J-shaped tube) having different straight tube portions and having a sufficiently large inner diameter of the arc portion. It is intended to be provided.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a U-shaped tube molding die of the present invention comprises a fixed mold having a U-shaped recess therein, a pair of mouth molds corresponding to the straight pipe part of the U-shaped pipe, and an arc of the U-shaped pipe. In a U-shaped tube molding die including a movable die having a pair of turning inner dies corresponding to the above-mentioned parts, a contact surface of the above-mentioned turning inner die is a U-shape along an axis of the U-shaped tube. It is characterized in that it is located on the line connecting the approximately equidistant point from the pipe end and the inside center point of the above-mentioned arc portion.

[0008]

[Work]

 According to the above configuration, the drafts of both the bores and the turning inner mold can be made the same, and the release areas can be made substantially the same. Therefore, a step does not occur at the contact part of the inner part of the rotation, the trouble of mold release defect can be reduced, and the inner diameter of the arc part can be made sufficiently large.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

This U-shaped tube molding die 10 includes a fixed die (female die) 11 having a half-split structure, and a movable die (male die) inserted in a U-shaped recess 12 formed in the fixed die 11. ) 13 and. The movable die 13 includes a pair of mouth dies 14a and 14b corresponding to the straight pipe portion P ₁ of the U-shaped pipe P and a pair of rotating inner dies 15a and 15b corresponding to the arcuate portion P ₂ of the U-shaped pipe P, respectively. , And a base portion 16 that supports them.

The mouth molds 14a and 14b are formed to have a length corresponding to the length of each straight pipe portion, and a base portion 14c is integrally formed, and the base portion 14c is formed in the base portion 16a. And is provided so as to be movable in the axial direction of the U-shaped pipe P. Further, crank rings 17, 17 are rotatably provided at the rear end of the base portion 16. The crank ring 17 is provided with one point on a straight line parallel to the axis of the U-shaped pipe P and passing through the arc center of the U-shaped pipe P as a rotation center. The inner molds 15a and 15b are connected by a parallel crank 20 composed of a pair of connecting shafts 18 and 19 which are parallel to the axis of the U-shaped pipe P penetrating the mouth molds 14a and 14b. Further, on the mouth molds 14a, 14b side of the crank ring 17, an arcuate surface 17a which abuts the rear end of the mouth molds 14a, 14b at the time of die cutting described later is connected to the connecting shaft 18 on the side far from the rotation center. It is formed around the connecting point 18a.

Among the connecting shafts 18 and 19 that connect the crank ring 17 and the rotating inner molds 15a and 15b, the connecting shaft 19 closer to the center of rotation of both is the rotating inner molds 15a and 15b. In order to maintain the positional accuracy with respect to the molds 14a and 14b, the moving direction is guided to the through holes formed in the respective molds 14a and 14b. Therefore, the connecting point 19a between the connecting shaft 19 and the crank ring 17 can be slightly moved by the elongated hole 17b formed in the radial direction of the crank ring 17 in order to absorb the change in the relative position of both. It is provided. On the other hand, the connecting shaft 18 on the side far from the center of rotation has a large diameter formed in the mouth dies 14a and 14b in order to respond to the positional changes accompanying the rotation of the crank ring 17 and the back inner dies 15a and 15b. It is loosely penetrated into the through hole.

Here, at the imaginary rotation center A of the rotation inner molds 15a, 15b rotated by the parallel crank 20, the locus of the outer surface of the rotation inner molds 15a, 15b does not hit the inner surface of the molded product. The connection points 18b and 19b between the rotary inner molds 15a and 15b and the two connecting shafts 18 and 19 are set to positions so that the respective constituent parts do not come into contact with the molded product, and have sufficient strength to withstand the molding injection pressure. Is set to a position where In addition, the rotation center B of the crank ring 17 and the connection points 18a and 19a with the connection shafts 18 and 19 have sufficient strength to withstand the molding injection pressure, and the operating space of each component is It will be installed at a position where it can be secured.

Further, the crank ring 17 is provided with a spring 21 for urging the crank ring 17 toward the fixed mold 11, and the abutting surfaces of the respective molds are arranged in a state where the molds are abutted with each other. Concavo-convex portion 22 is formed to ensure reliability.

In the mold of the present invention, as shown in FIG. 2, the contact surfaces (divided portions) S of the rotary back molds 15a and 15b are formed in a U-shape along the axis of the U-shaped pipe P. It is located on a line connecting a substantially equidistant point Y from the pipe ends X and Z and an inner center point A ′ of the arc portion P ₂ (a point on the inner surface of the molded product corresponding to the rotation center A). That is, the distances La and Lb along the respective axes from the U-shaped tube end surface Sa, Sb of the mouth dies 14a, 14b to the contact surface S of the rotary inner dies 15a, 15b are substantially equal to each other. It is set.

By setting the contact surfaces S of the rotary back molds 15a and 15b at such positions, even if the drafts of the respective mouth molds 14a and 14b and the rotary back molds 15a and 15b are made the same. A step does not occur at the abutting portion of the turning inner molds 15a and 15b, and the releasing areas can be made substantially the same. Therefore, it is possible to reduce the mold release defect trouble, to make the contact surface S substantially the same in shape, and to obtain a smoothly connected inner surface shape, so that the arc portion P ₂ of the U-shaped pipe P is The inner diameter can be made sufficiently large, and the drainage efficiency can be improved.

In the U-shaped tube molding die 10 having the above-described configuration, when the molding of the U-shaped tube P is completed, the mouth molds 14 a and 14 b first move on the base portion 16 in a direction away from the fixed mold 11, The rear end portions of the base portions 14c of 14a and 14b and the circular arc surface 17a of the crank ring 17 contact each other. The moving distances of the mouth molds 14a and 14b so far are as much as those of the mouth molds 14a and 14b and the back inner molds 15a and 15b above the positions where the rotation of the inner molds 15a and 15b does not interfere with the mouth molds 14a and 14b. The distance is set.

When the mouth dies 14a and 14b further move from this position, the crank ring 17 rotates with the movement of the mouth dies 14a and 14b, and as shown in FIG. The molds 15a and 15b are rotated to an extractable angle. The moving distances of the mouth molds 14a and 14b up to this point are such that the maximum inner dimensions of the rotary back molds 15a and 15b are perpendicular to the axial direction of the U-shaped pipe P. It is set to a comfortable distance. At this time, since the inner rotating dies 15a and 15b are rotated by the operation of the parallel link 20 accompanying the rotation of the crank ring 17, the sliding contact with the inner peripheral surface of the molded product can be minimized. Further, since the turning inner molds 15a, 15b at the time of turning are supported by the parallel cranks 20 supported by the crank ring 17 and the mouth molds 14a, 14b, the supporting strength is improved, and the turning inner molds 15a, 15b are The position of 15b can be stabilized.

Subsequently, by linearly moving the entire movable die 13 together with the base portion 16 in the pulling direction, the mouth dies 14a and 14b and the rotary inner dies 15a and 15b can be pulled out from the molded product. After that, the U-shaped pipe P after molding can be taken out by dividing the fixed mold 11 as in the conventional case.

In the present invention, the movable die-cutting mechanism is not particularly limited, and even if the other die-cutting mechanism is adopted, the contact surface of the turning inner die is as described above. By setting it, the same effect can be exhibited.

[0021]

[Effect of the device]

 As described above, in the U-shaped tube molding die of the present invention, the abutting surface of the turning inner mold has a contact surface of the arc-shaped portion which is substantially equidistant from the end of the U-shaped tube along the axis of the U-shaped tube. Since it is located on the line connecting the inner center point, even when forming a U-shaped pipe with different lengths of straight pipe parts, the draft of both mouth molds and rotary back molds can be made the same, and the mold release Since the areas can be made almost the same, the problems of defective molding during production are reduced. In addition, since the drafts are the same, the shape of the split parts of the rotary back mold can be made substantially the same, and the inner surface shape can be smoothly connected, so that the maximum drainage efficiency can be achieved.

[Brief description of drawings]

1 is a sectional view showing an embodiment of a U-shaped tube molding die of the present invention.

FIG. 2 is an explanatory diagram of a contact surface position of a turning inner mold.

FIG. 3 is a cross-sectional view showing a process of removing the movable die.

[Explanation of symbols]

10 ... U-shaped tube forming die 11 ... Fixed type 13 ... Movable type 14a, 14b ... Mouth type 15a, 15b ... Rotating back type L ... U-shaped tube axis La, Lb ... Distance P
… U-shaped pipe P ₁ … Straight pipe part P ₂ … Arc part S… Contact surface

Claims (1)

[Claims for utility model registration] [Claim 1] Fixed type (1) having a U-shaped recess (12) inside
1) and a pair of mouth dies (14a), (14b) corresponding to the straight pipe part (P ₁ ) of the U-shaped pipe (P) and a pair corresponding to the arc part (P ₂ ) of the U-shaped pipe (P). Of the movable type (1)
In a U-shaped tube molding die (10) provided with (3), the contact surfaces of the rotary back molds (15a), (15b) are connected to each other by the axis (L) of the U-shaped tube (P).
Is located on the line connecting the substantially equidistant point (Y) from the U-shaped pipe ends (X) and (Z) along the inner center point (A ′) of the circular arc portion (P ₂ ). Characteristic U-shaped tube molding die.