JPH02120024A - Automotive bumper blow molding method and molding device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a blow molding method and a molding apparatus for automobile bumpers.

Conventional technology Traditionally, when blow molding was used to mold bumpers for Mekintetsu, it had the great economic advantage of low mold production costs, but on the other hand, it was subject to restrictions on the molding shape. There was a problem. For example, if the function required for a bumper is deep from the front opening to the rear opening, such as a light mounting hole or an air intake hole, the base of the front opening may have a weak point in molding if the root becomes extremely thin. There is.

In particular, truck bumpers require an air intake for engine air cooling, but this intake has a long guide section to control the direction of air inflow, and it is necessary to narrow it down towards the back. , the product has a deep opening, and the rear opening needs to be molded narrowly. When blow molding such a shape, the mold (A) (
0), a protruding part (c), a receiving part) and a relief part (e) are provided in the part corresponding to the part where the rear opening of the bumper is to be molded, and molding using such a mold-ζ1 Therefore, a method was considered to prevent the thinning of the root by adding a front opening, but the angle (θ0) of the undercarpet became a problem and the mold would not come out after molding, so it could not be implemented, so the undercarriage j) was eliminated. Therefore, the functionality of the molded product deteriorates.

In addition, in a normal molding example (Fig. 6), the front opening (2) (periphery 13) becomes extremely thin, or the parison breaks during molding, resulting in a torn part (to), making molding impossible. There were drawbacks.

Problems to be Solved by the Invention In order to eliminate the drawbacks of the conventional technology, the present invention involves pressure-polymerizing two parisons forming the outer and inner walls of the bumper in a portion corresponding to the front opening of the bumper. This two-filter parison is further stretched and molded to form a bumper that does not break during molding and has a thick root with an opening.

Means for Solving the Problems The present invention provides a front opening +2 of a bumper (1) which is a molded product.
The peripheral edge part (3) of 1 is formed by two parisons by overlapping and pressing the outer parison (4) and the inner parison (5), and a reinforcing rib + is provided on the outer peripheral edge of the rear opening 1I5).
(6) In order to form the front side mold (61), the bumper (
A core (8) having the same shape as the inner surface of the open cylindrical part (7) of 1) is slidably fitted from the inside (6a) of the front side mold (61) to the outside of the cavity (6b), and the inside of the open cylinder part (7) of 1) is fitted so as to be freely slidable. 191
is formed with a recess (111) corresponding to the core (6), into which the bulge uQl and the core (8) are fitted and removed, and the recess (111)
The two outer parisons (4) and the inner parison+ which have been polymerized by the core (8)
5) is compressed into the core (8) to form nine air chambers t]z, and the air chamber 0 is transferred to the bulged portion u1.

An air passage 03 is bored through the core (8), and a protruding rod (with a protruding rod) that slides in the same direction as the sliding direction of the core (8) is inserted into the inner corner of the recess 0υ. (llb), when the core (8) is fitted into the recess 0111 after mold clamping, the core (8)
) and the outer parison (4).
and the inner parison (+5) are provided protrudingly.
; When pushing through, the outer parison (4) and inner parison (
5) Add 0 extra thickness to the outer periphery of the rear opening ((5) of the bumper (1) to form a groove tt'rI for forming the reinforcing rib 11B+, and further add the groove tt'rI to the front surface (lie) of the recess 111.
A lid is formed at the top.

Function To explain the function of the present invention in part b, similar to normal blow molding, a parison is extruded into a cylindrical shape from the blow head between the front side mold (6) and the back side mold 19), and the mold is clamped. When the blowing starts, the outer parison 14) is inserted into the cavity of the front mold (6) <6b) as shown in Figure 3.
, the inner parison (5) is joined to the cavity (9a) of the back side mold (91), and the tip (10
1)) approaches the cavity (6b) of the front side mold (6), so the inner parison (5) in the area surrounded by the bulge part utvuctJ is polymerized and crimped to the outer parison (4), and the bumper The front opening (21 is the root crimping part) is set by the parison with a volume of 2 ml.In parallel with the above movement, the guide length of the front mold (6) is When the core (8), which had been immersed in the hole (6c), was protruded, the parison +4), which had been positioned in a polymerized and flattened state, was located in front of the core (8).
The front surface (8b) of the core (8) comes into contact with 5), and as the mold clamping progresses, the joining and expansion of the parison (4) +5) spreads to the surrounding parison +4) +5), and the joined part lζ The air interposed between the parisons +4) and +5) is pushed to the upper and lower parts where they do not join. The protruding rod I in the core (8) protrudes and forms a double parison (4).
5+ is stretched toward the recess a11. Furthermore, core (8
) gradually advances toward the recess [113] while pushing the parison +4) (5), and presses the crimped part uF around the front opening (21).
The opening mold space sealed by j, that is, the recess (11
The air between the inner peripheral surface (ll&) of 1 and the outer surface of the inner parison (5) passes through the air chamber (3) and the air passage (3), and is sucked by an external odor pump (not shown). The outer parison (4) is removed by protruding the protruding rod (4) and reducing the exhaust pressure.
) and the inner parison (5) are elongated on average, with protruding bars (
Upon completion of stretching in (4), the corner (8a) of the core (8)
is pushed out until it collides with the cutout (10a). At this time, the parison +4 that was in contact with the front surface (8b) of the core (8)
)(5) is press-fitted into the parison relief part (11 revision) of the fourth part (IIl), and the excess thickness of the parison is press-fitted into the groove dη of the bulge part u0, and after molding, the rear opening f(5) of the bumper 111 is press-fitted. A protruding edge serving as a reinforcing rib ((6)) is formed on the outer peripheral edge of.

On the other hand, when the core (8) completes its entry (Fig. 4), an air chamber G21 remains between the inner circumferential surface (ll&) of the recess 01) and the outer surface of the inner parison (5), so that the air An air passage (
The reparison (4) f5+, in which air is injected through 13, is brought into close contact with the outer circumferential surface (8C) of the core (8), and the grain on the outer circumferential surface of the core (8) is clearly transferred and molded. Then, the mold is released to obtain a molded product.

Example An example of the present invention will be explained with reference to the drawings.
61, a guide elongated hole (6C) is bored from the inside toward the cavity (6b) at a location I corresponding to the portion where the open cylindrical portion (7) of the bumper 111 is to be formed, and the guide length is Fit the core (8) into the hole (6C) so that it can freely come out and go out.The core (8) has a bumper that extends to the tip of the bumper so that it corresponds to the opening cylinder part (7) of J, as shown in Fig. 3. Accordingly, the core (8) is formed into a narrow pyramidal shape with a strong slope, and a protruding rod (4) that can freely protrude and retract in the same direction as the core (8) is hermetically fitted into the core (8). On the back side mold (91), a bulging separate opening is formed in a portion corresponding to the core (8), and a recessed opening into which the core (8) can be fitted is bored into the bulging portion U. The inner circumferential surface (111) of this concave portion Lllll has 2 points between it and the outer circumferential surface (8C) of the core (8) when the mold is clamped.
It is formed by polymerizing the parisons +4) +5) to leave a thick wall and some air chambers a21.
lb) Nearby there is a groove t171 for forming the reinforcing rib 1 (6)
At the same time, cut-out portions (10a) are formed at the corners, which abut against the corner portions (8a) of the core +8) when fitted. Then, from one side of the bulging portion 11G to the outside of the m-side mold 19), an air passage is connected to the air chamber (12+) and to a vacuum pump (not shown) outside the mold. Drill 03.

According to the method and equipment of the present invention, the parison of the portion corresponding to the front opening of the bumper is double-polymerized, stretched from the front opening to the rear opening, and brought into close contact with each other for blow molding. Therefore, the opening periphery of the front opening is double-molded and thickened, and there is no problem such as breakage in the Cc# part during blow molding, and this part of the molded product is made of the inner parison. Reinforced by solidification to provide impact resistance and
A molded product with excellent durability can be obtained. In addition, since there is no undercut in the mold to form the opening, it is not impossible to release the mold, and together with the fact that the core and protruding rod are slidable, it is possible to release the mold smoothly and quickly. Can be released from the mold. Further, since reinforcing ribs are formed on the outer periphery of the rear opening, this part becomes strong, and together with the fact that the periphery of the front opening is made double and thick, vibration resistance is improved. Furthermore, the double parisons stretched by the core and the protruding rods are brought into close contact with each other by the air pressure sent from the air passage, and the degree of transfer is also increased. This method does not require much complexity and exhibits an excellent effect when blow molding a bumper having an opening.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 is a perspective view of a bumper which is a molded product, Fig. 2 is an enlarged cross-sectional view taken along the line AA in Fig. 1, and Fig. 3 is a cross-sectional view of the main parts of the device. The enlarged view shows the state of the parison in the opening molded part and the relationship between the front side mold and the back side mold when mold clamping is completed. FIG. 4 is an enlarged sectional view of the main part during the process of fitting the core into the recess and forming a double parison. Figures 5 and 6 are conventional examples, Figure 5 is a cross-sectional view of a mold with an undercut attached to the back side mold, and Figure 6 is a fracture in the parison when the mold is closed and blown. FIG. 3 is a cross-sectional view of the mold showing a state in which this occurs. Code: 1...Nokun no size -2...
Front opening 3...Peripheral portion 4...Outer parison 5...Inner parison 6...Front side mold 6a...Inner part 6b ...Cavity 6C...Guiding slot 7...Opening tube part 8...Core 8a...Corner part 8b... ...Front surface 80...Outer peripheral surface 9...Back side mold 9a...Cavity 10...Bulging part 10a...Bulging part 10b... Tip 11...Concave portion 11a...Inner peripheral surface 111)...Corner corner 11c...Front surface 11 (1...Paris relief part 12...Air chamber 13...Air passage 14...Protruding rod 15...Rear opening To the inventor

Claims (4)

[Claims] (1) The central line part (3) of the front opening (2) of the bumper (1)
) is formed by two parisons by polymerizing and pressing an outer parison (4) and an inner parison (5). (2) Inside the front mold (6), insert a core (8) having the same shape as the inner surface of the open cylinder part (7) of the bumper (1) from the inside (6a) of the front mold (6) to the outside of the cavity (6b). The core (8) is slidably fitted into the back side mold (9).
), a recess (11) into which the bulge (10) and the core (8) are fitted and removed is formed, and the inner circumferential surface (1) of the recess (11)
1a), the two outer parisons (4) and inner parisons (5) that have been polymerized by the core (8) are added to the core (8).
) is formed with an air chamber (12) for pressure forming, and an air passage (12) communicating with the air chamber (12) is formed in the bulging portion (10).
13) A blow molding device for an automobile bumper, characterized in that the blow molding device has a perforation. (3) An automobile according to claim 2, characterized in that a protruding rod (14) that slides in the same direction as the sliding direction of the core (8) is fitted into the core (8). Blow molding equipment for bumpers. (4) When the core (8) is fitted into the recess (11) after mold clamping, the corner (8a) at the tip of the core (8) Butt the outer parison (
4) and the cutout part (10a) that presses out the inner parison (5).
is provided protrudingly, and an outer parison (4) and an inner parison (
5), when pushing out the outer parison (4) and the inner parison (5), extra thickness is added to the outer periphery of the rear opening (15) of the bumper (1) to form reinforcing ribs (16). A groove (17) is formed, and the front surface (11) of the recess (11) is formed.
The blow molding apparatus for an automobile bumper according to claim 2, characterized in that a burr relief part (11d) is formed in c).