JPH08150656A - BLOW MOLDING DEVICE FOR BOOT AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the formation of defects that cause damage to the small-diameter mounting part of the boot. [Structure] The injection port (3) of the nozzle and the inner peripheral surface (43) of the end of the blow molding die are formed to have a diameter larger than the inner diameter of the fastener groove forming surface (24) of the small-diameter mounting portion die, and the injection cavity (3
The molding apparatus and the manufacturing method are capable of blow molding the parison to form a boot in which cracks do not occur at the corners of the fastener groove while promoting the molding of the small-diameter mounting portion of the boot in 0). .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding apparatus and method for manufacturing boots. In particular, the present invention relates to a blow molding apparatus in which molding of a boot mounting portion is improved and a manufacturing method thereof.

The prior art relating to the present invention includes, for example, Japanese Patent Laid-Open No. 6-201042. In this publication,
The apparatus for forming the boot shown in FIG. 6 is shown. FIG.
It is sectional drawing of the shaping | molding die in the state which blow-molds. FIG.
FIG. 4 is a cross-sectional view of a mold in a pre-process for molding a parison.

In FIGS. 6 and 7, reference numeral 51 is a small-diameter fixing portion mold. This small diameter fixing part mold 51 has a hole 6 inside.
8 and the opening side of the hole 68 is formed in the groove forming surface 64. The open end face is formed on the joint end face 66.

The core mold 52 fitted in the hole 68 has a molding surface 70 on the end side, and an injection molding cavity 53 is formed between the molding surface 70 and the groove molding surface 64. Furthermore,
A blow hole 63 is formed in the core die 52 in the axial direction so that the pressure fluid can be introduced into the blow die 57.

The small-diameter fixing portion die 51 holding the end of the parison 62 is reciprocally movable with respect to the die 54 arranged at the opposite position, and moves from the state of FIG. 7 to the state of FIG. To form a parison.

The die 54 has a guide injection hole 56 for injecting a molding material. The mandrel 5 is placed in the injection hole 56.
5 are arranged. Then, the injection flow path 50 for introducing the molding material is formed between the injection hole 56 of the die 54 and the outer peripheral surface of the mandrel 55. The exit side of the injection flow path 50 is connected to the inner conical surface of the injection hole 56 of the die 54 and the mandrel 55.
An orifice injection port 69 is formed between the taper outer surface and the taper outer surface. The outer diameter of the orifice injection port 69 and the outer diameter of the injection molding cavity 53 are formed to have the same size.

The end surface of the die 54 has an adhesive surface 67 which is a surface that forms an acute angle corner portion 65 with the inner surface of the cone, and the joint end surface 66 of the small diameter fixing portion die 51 is seated on this adhesive surface 67.
This state is shown in FIG. As shown in FIG. 7, in a state where the small-diameter fixing portion die 51 is seated on the die 54, the injection flow path 50
A molding material 61 is injected into the injection molding cavity 53 from. Then, the small-diameter fixing portion die 51 pulls the molding material 61 while holding it in the injection molding cavity 53, moves to the state shown in FIG. 6, and forms the parison 62. At this time, the interior of the injection molding cavity 53 to the parison 62 is in a thermoplastic state.

A blow mold 5 divided into two parts on both sides of the parison 62 with the parison 62 formed.
7, 57 move into the illustrated state of FIG. 6 and join to form a blow molded cavity. The blow molding cavity of the blow mold 57 is formed by the partial molding surface 71 of the small diameter fixing portion, the bellows molding surface 58, the large diameter fixing portion forming surface 59, and the burr portion molding surface 60.

A pressure fluid is introduced into the parison 62 from the blow hole 63, and the pressure of this fluid causes the parison 62 to be pressurized.
Expands to the molding surface of the blow mold 57 to mold the boot.

[0010]

In the step of forming the boot, the die 54 and the small diameter fixing portion mold 51 are joined in the state shown in FIG. 7, and the high temperature molding material 61 is smaller than the injection flow passage 50 in the small diameter fixing portion. It is injected into the injection molding cavity 53 in the mold 51. Then, while the molding material 61 injected into the small-diameter fixing portion die 51 is held in a thermoplastic state, the molding material 61 in the injection channel 50 is formed into a cylindrical parison 62 and pulled up.

At this time, the wall thickness of the parison 62 on the side of the small diameter fixing portion mold 51 is substantially the same as the radial dimension of the injection molding cavity 53, as shown in FIG. Then, when the fluid pressure acts on the parison 62 from the blow hole 63 in the state shown in FIG. 7, the parison 62 expands and the boot is formed by the molding surface of the blow mold 57.

In the molding of this boot, the side surface (upright portion) of the recess for the boot tightening tool is formed by the joint end surface 66 of the small-diameter fixing portion mold 51, but the outer peripheral surface of the parison 62 and the blow mold 57 are formed. There is a gap between the partial molding surface 71 and the parison 62, and the parison 62 is expanded by this gap and blow molded. For this reason, the thickness of the parison 62 strictly regulates the dimension of the side surface (upright portion) of the recess, which causes a defect.

Moreover, since the solidification of the parison 62 in this portion is progressing at this point, the small-diameter fixing portion die 5 is formed.
The corners 65 of No. 1 cause cracks and shrinkage cavities. In particular, since this portion of the boot corresponds to the boundary between the injection-molded portion and the blow-molded portion, it is structurally unstable and may lead to breakage. In particular, stress tends to concentrate at this point during use as a boot.

The present invention has been made in view of the above problems, and an object of the present invention is to obtain a molding apparatus and a method for manufacturing the molding apparatus that eliminates a defect that causes damage to a small-diameter mounting portion of a boot.

[0015]

The present invention has been made to solve the above-mentioned problems, and its technical means is configured as follows.

That is, in a blow molding apparatus for applying a fluid pressure to a parison to mold a boot having a small diameter mounting portion at one end of a bellows portion and a large diameter mounting portion at the other end,
A blow molding die that has at least a large-diameter mounting portion molding surface and one inner peripheral surface of the bellows molding surface and is opened and closed separately, and is arranged so that it can be joined to the opening portion of the blow molding die on the large-diameter mounting portion molding surface side. An injection device having a nozzle having a nozzle injection port at one end of the introduction hole for the molding material and a nozzle core arranged in the introduction hole of the nozzle to adjust the thickness of the parison, and arranged at a position facing the injection device. It has a fastener groove forming surface which is connected to the nozzle injection port of the nozzle and is also connected to one end of the bellows forming surface of the blow molding die so as to be able to communicate. The small-diameter mounting part mold having an end face that is joined to the opening end face of the inner peripheral surface of the blow molding die in the opening part of the blow-molding mold and the small-diameter mounting part mold, and is fitted into the small-diameter mounting part mold to face the fastener groove forming surface to form an injection cavity Injection mold with mandrel and injection molding After the molding material is injected from the injection device into the injection cavity of the injection molding device, a moving means for moving the injection mold reciprocally to the position of the blow molding mold end opposite to the injection device while forming the parison is provided. The blow molding apparatus is configured such that the diameter of the nozzle injection port and the diameter of the inner peripheral surface at one end of the bellows portion molding surface are larger than the diameter of the forming surface.

Further, the nozzle injection port of the injection device and the injection cavity of the injection mold are joined in a communicating state by the moving means, and the molten resin is injected from the nozzle injection port into the injection cavity to form the small-diameter mounting portion. In addition, the moving means relatively moves the injection molding die from the injection device to form an outer diameter of the parison that is larger than the outer diameter of the fastener groove of the small-diameter mounting portion, and the split blow molding die is closed from both sides of the parison. This is a blow molding method in which both openings of the blow molding cavity are closed by the nozzle and the end surface of the small diameter mounting portion mold, and a pressure fluid is introduced into the parison from the blow hole to mold the boot.

[0018]

The molten resin in the molding material flow passage is injection-molded into the molding cavity by joining the nozzle injection port of the injection device by the moving means so as to communicate the entrance of the fastener groove forming surface of the injection molding die. At this time, since the small-diameter mounting portion mold is kept at a temperature far lower than the temperature of the molten resin, the resin in contact with the small-diameter mounting portion molding surface and the end surface is rapidly cooled, and the molding is promoted in the vicinity of this surface. Next, since the molten resin is supplied from the molding material flow passage and the injection mold is moved to the other end by the moving means, the parison is formed into a cylindrical shape. This parison moves while forming the shape of the small-diameter mounting portion of the boot because the nozzle injection port is formed larger than the diameter of the fastener groove forming surface.

Next, with the parison formed, the split blow molding dies arranged on both sides are combined to form a blow molding cavity. Then, since the pressure fluid flows into the parison through the blow hole, the parison expands along the boot molding surface, and the boot is blow molded. At this time,
Since the connection between the small-diameter mounting part and the bellows part is not greatly deformed by the blow pressure, there is no structurally unstable strain, cracking does not occur, and the shape as set is molded very well. It

[0020]

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

FIG. 1 is a sectional view of a main part of a molding apparatus showing an embodiment of the present invention. 3 and 4 are enlarged views of the small-diameter mounting portion mold side of FIG. Description will be made with reference to FIGS. 1, 3 and 4. The nozzle 1 has an introduction hole 2 inside,
The injection port 3 of the introduction hole 2 is formed on a circumferential surface having a width of several mm, and a conical surface 4 is provided between the inside of the introduction hole 2 and the injection port 3.
Is formed. By forming a circumferential surface having an axial width on the exit side 3 of the conical surface 4 on the outlet side, the outer diameter of the parison can be set to the dimension. In particular, the effect on heat can be calculated to determine the contour of the parison.

A nozzle core 5 is arranged in the introduction hole 2. The tip portion 6 of the nozzle core 5 is formed on the frusto-conical surface 8 and has a fitting hole 7 in the tip surface. This fitting hole 7
Is formed so that it can be connected to the tip portion 26 of the mandrel.

An orifice nozzle is formed between the conical surface 4 of the nozzle and the top conical surface 8 of the nozzle core 5 (the nozzle core 5 moves in the C direction), and the gap including the orifice nozzle is made of the molten resin 39. The flow passage 9 is formed. The flow passage 9 communicates with a passage for feeding the molten resin 39 by a pressure piston (not shown). The nozzle 1, the nozzle core 5, and the pressure piston constitute an injection device 45.

At the upper part of the nozzle 1 in the drawing, a blow molding die 10 which is divided into two parts is constructed so that it can be opened and closed in the two-part direction (direction A) by a mold opening / closing means 40. Then, the blow molding cavity 10 is formed by closing the half of the blow molding die 10. This blow molding cavity 1
The surface forming No. 1 is the burr portion molding surface 1 from the nozzle 1 side.
2, the large-diameter mounting portion molding surface 13, the bellows portion molding surface 14, and the bellows end inner peripheral surface 43.

Further, on the upper part of the blow molding die 10, a small-diameter mounting portion die 15 is arranged. The small diameter mounting type 15
The outer peripheral surface of the tip is formed as a tapered outer surface 21, and the tip is divided into three along the axial direction to form a collet chuck.

The small-diameter mounting portion die 15 is formed on the fastener groove forming surface 24 on the inner peripheral tip side. Also, the mold end surface 20
Is configured so as to be able to come into close contact with the bonding surface 25 of the nozzle 1 and the bonding surface 44 of the blow molding die 10 together with the molding surface forming the side surface of the fastener groove.

A mandrel 18 is provided inside the small-diameter mounting portion die 15, and a sleeve 19 is provided between the small-diameter mounting portion die 15 and the mandrel 18. On the tip side of the mandrel 18, a small-diameter mounting portion molding surface 22
Are formed. An injection cavity 30 is formed between the small-diameter mounting portion molding surface 22 and the fastener groove forming surface 24.
A blow hole 29 is provided in the central axis direction. Further, the tip portion 26 is formed so as to be fitted into the fitting hole 7 of the nozzle core 5.

The support portion 16 arranged outside the small-diameter mounting die 15 is formed on the same tapered inner surface as the tapered outer surface 21 of the small-diameter mounting die 15. Further, on the outer peripheral side thereof, a temperature adjusting flow path 28 is provided between the temperature adjusting flow path 28 and the casing 17, so that the temperature of the small diameter mounting die 15 can be set by passing a liquid through the temperature adjusting flow path 28. become. A fluid flows into the temperature control flow channel 28 corresponding to a temperature sensor in order to precisely mold the temperature and keep the temperature in the injection cavity constant.

The supporting portion 16 and the casing 17 are constructed so as to move in the axial direction (E direction), so that the third portion of the small-diameter mounting portion die 15 can be opened and closed (moved in the D direction). ing. This opening / closing allows the molded small-diameter mounting portion 35 to be released.

This small-diameter mounting section mold 15, mandrel 18,
The injection mold 46 is formed by the support portion 16 and the casing 17.
Is configured.

The injection mold 46 is reciprocally moved (B) by the mold moving means 41 from the position where it is joined to the nozzle 1 shown in FIG. 2 to the position where it is fitted into the blow mold shown in FIG.
Direction).

The moving speed of the mold moving means 41 is configured to be linked with the molten resin injection speed of the injection device 45 by the computer control device, so that the wall thickness of the parison can be optimized.

Next, a method for manufacturing the boot of the present invention will be described. FIG. 2 is a sectional view in which an injection mold 46 is joined to the injection device 45. In Fig. 2 (Fig.
1), the injection cavity 30 of the injection mold 46 is joined by the mold moving means 41 shown in FIG. 1 so as to communicate with the injection port 3 of the injection device 45.

Then, the molten resin 39 is injection-molded into the injection cavity 30 of the injection molding die 46 from the injection port 42 through the flow passage 9 from the injection portion 42 having a pressure piston (not shown). The distance between the injection port 3 and the truncated conical surface 8 can be adjusted by adjusting the injection amount of the molten resin 39 by moving the nozzle core 5 in the axial direction by the core moving means 27. It is also adjusted by the pressure of the injection part 42. By this adjustment, the thickness of the parison 23 can be changed along the axial direction. The adjustment of the nozzle core 5, the injection pressure, and the moving speed of the injection mold 46 are controlled by a computer.

The molten resin 39 (200 ° C. or higher) injected into the injection cavity 30 is temperature-controlled at a constant temperature by the temperature-controlling channel 28, and the small-diameter mounting portion mold 15 (15-3).
The molding proceeds at 0 ° C. The molten resin 39 in contact with the fastener groove forming surface 24 and the mold end surface 20 forms the parison 23 as the injection molding die 46 moves while forming this surface. The thickness of the parison 23 changes the dimension on the inner diameter side to match the thickness of the boot.

Since the outer diameter of the parison 23 is determined by the diameter of the injection port 3, the parison 23 can be formed to have a larger diameter than the fastener groove forming surface 24. Further, since the injection port 3 is formed on the inner peripheral surface having the axial width, the outer diameter of the parison 23 can be formed constant.
The change of the diameter of the inner peripheral surface due to the heat of the parison 23 is also taken into consideration.

When the injection molding die 46 reaches the upper end by the die moving means 41, the blow molding die 10 arranged in the open state on both sides of the parison 23 is closed by the die opening / closing means 40, and is opened inside. The blow molding cavity 11 is formed.

When the blow molding die 10 is closed, the die end surface 20 of the small-diameter mounting portion die 15 is separated by several mm above the joining surface of the blow molding die 10. Then, with the blow molding die 10 closed, the mold end surface 20 is
To join. At this time, the parison 23 is compressed in the axial direction. However, since the molding of the parison 23 on the small-diameter mounting portion side is more advanced than the lower side, no bulge occurs.

The dimensional relationship between the state in which the blow mold 10 is closed and the parison 23 is as shown in FIG. 3 or 4. That is, the outer diameter B of the parison 23 is slightly smaller than the inner diameter C of the end inner peripheral surface 43 of the bellows molding surface 14 (about 1-2 mm).
Or, they are formed substantially the same. And this B and C
Is larger in diameter than the inner diameter A of the fastener groove forming surface 24. The B dimension may be slightly larger than the C dimension (preferably within 1 to 2 mm). In addition, the mandrel 18 is configured to be movable toward the parison 23 in order to improve the connecting portion between the small-diameter mounting portion 35 and the bellows portion 37.

Next, the pressurized fluid is introduced into the parison 23 through the blow hole 29 to form the boot, but the connection between the boot and the small-diameter mounting portion 35 and the bellows portion 37 is not extremely extended. Therefore, the molding is performed very well and the molding surface is precisely formed.

The boot 38 shown in FIG. 5 is a half sectional view of the boot formed by the manufacturing method of the present invention. Boots 3
A burr portion is formed on the large-diameter mounting portion 36 of No. 8, but is cut and separated from the boot 38 by a burr cutting knife 49. The boot 38 includes a large diameter mounting portion 36 and a small diameter mounting portion 35.
And a space between them is linked by the bellows portion 37. Then, on the inner peripheral surfaces of the small diameter mounting portion 35 and the large diameter mounting portion 36,
Each has a seal portion 33 and a lip portion 34. or,
A fastener attachment groove 31 is provided on the outer peripheral surface of the small-diameter attachment portion 35.

The material of the boot is a thermoplastic elastomer such as polyester type elastomer, polyurethane type elastomer, polyolefin type elastomer and polyamide type elastomer. These have the properties of elastic plastics.

[0043]

According to the blow molding apparatus and the manufacturing method thereof of the present invention, since the injection hole of the nozzle is formed to have a diameter larger than the inner diameter of the fastener groove forming surface of the small diameter mounting portion type, the outer diameter of the parison is reduced. It is possible to easily form a larger diameter than the outer diameter for forming the fastener groove of the small-diameter mounting portion without increasing the dimensional accuracy of the molding device to increase the cost and without using an expensive computer control device. it can. As a result, the boot can be blow-molded without causing cracks at the corners of the fastener groove. Further, since the boundary between the small-diameter mounting portion and the bellows portion corresponds to the boundary between the injection molding range and the blow molding range,
Conventional products are structurally unstable and may be damaged by bending during use, but the boot of the present invention can bring the blow molding range very close to the small diameter mounting part side of the injection molding range. Therefore, this portion is less likely to be bent during use. Further, since the outer diameter of the parison and the inner peripheral surface of the end of the blow molding surface are close to each other, blow molding can be performed without causing internal strain, and the durability performance is systematically exhibited. Also, since the small-diameter mounting part is being molded by the small-diameter mounting part mold during parison molding, when the divided blow molding mold is closed, the small-diameter mounting part mold is separated in the parison axial direction, and then the small-diameter mounting part mold is blown. Although it is joined to the forming die, at this time, a flash occurs in the small-diameter mounting portion in the conventional one. However, since the small-diameter mounting portion of the present invention is being molded, burrs do not occur. Furthermore, since this small-diameter mounting part mold is joined to the blow molding mold, the parison that has been stretched once is compressed again, so that the conventional one forms expansion parts on both sides near the end face of the small-diameter mounting part mold of the parison, In the manufacturing method of the present invention, since this portion is in the process of being molded, it does not expand, and dimensional defects do not occur in the molding of the side surface (the rising surface) of the fastener groove.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a blow molding apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a joined state of an injection device and an injection molding die according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing injection molding in a coupled state of a blow molding die and a small diameter mounting portion die according to an embodiment of the present invention.

FIG. 4 is a sectional view showing injection molding in a coupled state of a blow molding die and a small diameter mounting portion die according to another embodiment of the present invention.

FIG. 5 is a half sectional view of a boot formed by the manufacturing method of the present invention.

FIG. 6 is a sectional view of a conventional blow molding device.

FIG. 7 is a cross-sectional view of a state in which a die of a conventional example and a small-diameter fixing portion die are connected.

[Explanation of symbols]

 1 …… Nozzle 2 …… Introduction hole 3 …… Injection port 4 …… Cone surface 5 …… Nozzle core 6 …… Tip portion 7 …… Mating hole 8 …… Mounted conical surface 9 …… Flow passage 10 …… Blow Molding die 11 ... Blow molding cavity 12 ... Burr molding surface 13 ... Large diameter mounting portion molding surface 14 ... Bellows portion molding surface 15 ... Small diameter mounting portion mold 16 ... Supporting portion 17 ... Casing 18, 55 ...... Mandrel 19 ...... Sleeve 20 ...... Mold end surface 21 ...... Tapered outer surface 22 ...... Small diameter mounting part molding surface 23, 62 ...... Parison 24 ...... Clamping tool groove forming surface 25,67 ...... Adhesive surface 26 ...... Tip part 27 ...... Core moving means 28 ...... Temperature control flow path 29, 63 ...... Blow hole 30 ...... Injection cavity 31 ...... Clamping tool mounting groove 32 ...... Groove side surface 33 ...... Seal part 34 ...... Lip part 35 …… Small diameter mounting part 36 …… Large diameter mounting part 37 ... Bellows part 38 ... Boots 39 ... Molding material (resin) 40 ... Mold opening and closing means 41 ... Mold moving means 42 ... Injection part 43 ... End inner peripheral surface 44 ... Joining surface 45 ... Injection device 46 …… Injection mold 47 …… Opening 49 …… Burr cut scalpel 50 …… Injection flow path 51 …… Small diameter fixed part mold 52 …… Core mold 53 …… Injection molding cavity 54 …… Die 56 …… Injection hole 57 ... Blow mold 58 ... Bellows molding surface 59 ... Large diameter fixed portion molding surface 60 ... Burr molding surface 61 ... Molding material 64 ... Groove forming surface 65 ... Corner 66 ... Joining end surface 68 ... Hole 69 ... Orifice injection port 70 ... Molding surface 71 ... Part 1 molding surface X ... Injection molding range Y ... Blow molding range

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29L 31:26

Claims (2)

[Claims] 1. A mounting portion (3) having a diameter smaller than that of the parison (23).
5), a blow molding device for molding a boot having a large-diameter mounting portion (36) and a bellows portion (37), wherein a large-diameter mounting portion molding surface (13), a bellows molding surface (14), and the bellows molding A blow molding die (10) which has an inner peripheral surface (43) at an end of a surface (14) and is opened / closed in a split manner, the blow molding die (1)
Nozzle (1) having a nozzle injection port (3) which is arranged so as to be joined to the opening (47) on the molding surface (13) side of the large diameter mounting part (0) and is one end of the introduction hole (2) for the molding material. And an injection device (5) which is disposed in the introduction hole (2) of the nozzle (1) and adjusts the wall thickness of the parison (23) between the nozzle injection port (3) and the nozzle core (5). 45), which is arranged at a position facing the injection device (45) and can communicate with the nozzle injection port (3), and within the end of the bellows molding surface (14) of the blow mold (10). Small diameter mounting die (1) having a fastener groove forming surface (24) forming an injection cavity (30) capable of communicating with the peripheral surface (43).
5) and the small diameter mounting part mold (15), and the injection cavity (30) is fitted between the fastener groove forming surface (24).
And a parison (23) after injecting a molding material from the injection device (45) into an injection mold (46) having a mandrel (18) forming a mold and the injection cavity (30) of the injection mold (46). And a mold moving means (41) for reciprocally moving the injection mold (46) to the position of the end of the blow mold (10) opposite to the injection device (45). Attachment groove forming surface (2
A boot blow molding apparatus in which the diameter of the nozzle injection port (3) and the diameter of the end inner peripheral surface (43) of the bellows molding surface (14) are larger than the diameter of (4). 2. The mold moving means (41) joins the nozzle injection port (3) of the injection device (45) and the injection cavity (30) of the injection mold (46) in a communicating state, Molten resin is injected into the injection cavity (30) from the nozzle injection port (3) to attach a small diameter portion (35).
Then, the injection molding die (46) is relatively moved from the injection device (45) by the die moving means (41), and the fastener attachment groove forming surface (of the small diameter attachment portion (35) ( Two
The outer diameter of the parison (23) is larger than the diameter of 4), and the blow molding die (10) divided from both sides of the parison (23) is closed by a die opening / closing means (40). The nozzle (1) and the end face of the small-diameter mounting part mold (15) close the openings at both ends of the blow molding cavity (11),
A method for manufacturing a boot, wherein a pressure fluid is introduced into the parison (23) through a blow hole (29) to mold the boot.