JPH07112709B2 - Hot Tranna for injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an injection molding machine, in which a nozzle of an injection device and a resin supply hole of a mold are connected to each other to heat resin injected from the nozzle. Meanwhile, the present invention relates to a hot runner which is transferred and supplied to a mold.

[Conventional technology]

A hot runner of this type is disclosed in, for example, JP-A-60-63123.
The device disclosed in the publication is generally configured as follows. That is, the injection device, which is formed so as to be movable in the horizontal direction as a whole, includes a heater and a screw that melts the resin supplied from the hopper and transfers the resin in the horizontal direction. A nozzle for ejecting the transferred molten resin in the horizontal direction is mounted. A molding device including a lower mold fixed to a fixed plate and a vertically movable upper mold located above the lower mold is disposed in the nozzle direction of the injection device. A resin passage communicating with the cavities formed in these two dies is formed in the mold so that a resin supply hole which is a lower end opening of the mold is directed downward.

Between such an injection device and the molding device, a hot runner is provided to transfer the resin injected from the nozzle of the injection device while heating and supply the resin to the mold. This hot runner is provided with a heater for heating a resin and extends horizontally from the nozzle toward the lower part of the mold, and a chip mounted perpendicular to the tip of the runner body is formed into an approximately L-shape. The nozzle end of the runner main body is supported by fitting the trunnion and the pin so as to be swingable and slightly movable in the axial direction. Further, the runner body is provided with a resin passage communicating with the resin supply hole of the chip and penetrating the shaft core portion, and opening to the end portion on the nozzle side, and on the swing end side of the runner body. Is provided with a guide plate that makes sliding contact with the swing end surface that moves by swinging. Further, a vertical rocking cylinder is provided below the rocking end of the runner body, with the working end of the piston rod abutting the lower surface of the runner body.

With this configuration, when the injection device is moved in the horizontal direction and its nozzle is pressed against the adapter provided in the resin passage opening of the runner body, the runner body moves slightly and swings in this state. When the rocking end of the runner body is raised by the cylinder, the tip rises and is pressed against the resin supply hole of the die.

With this configuration, when the molten resin is extruded from the nozzle of the injection device, the molten resin passes through the resin passage of the runner body and the hole of the chip while being heated by the heater, and the resin is supplied from the resin supply hole to the mold. It is supplied into the cavity and molding is performed. The thermal expansion of the runner body is absorbed by the long holes provided in the trunnion portion.

[Problems to be Solved by the Invention]

However, in such a conventional hot runner, since the swing end surface of the runner body that makes an arc motion is guided by sliding contact with the fixed guide plate, the guide plate and the runner body are easily worn, Further, there is a problem that the contact portion between the piston rod working end surface of the swing cylinder and the swing end lower surface of the runner body makes a linear contact by sliding, so that it is easily worn and lacks reliability. Further, since the trunnion portion is provided with a gap for absorbing thermal expansion, there is a problem that the runner body is not swung smoothly.

The present invention has been made in view of the above points, and an object of the present invention is to provide a hot runner for an injection molding machine that is less worn and operates smoothly.

[Means for Solving the Problems]

In order to achieve such an object, according to the present invention, a runner body having a base end portion supported by a bearing in the vicinity of a resin injection nozzle so as to be swingable via a trunnion is provided with a swing end portion below a resin supply hole of a mold. The roller on the machine base side is abutted on the swing end surface of the runner main body, and the swing end surface is pressed against the roller by a disc spring provided at the base end of the runner main body. , A fluid pressure cylinder is provided below the swing end of the runner body, the working end of the bendable piston rod is fixed to the lower surface of the runner body, and the piston rod is raised to swing the runner end. The chip provided on the mold was pressed against the resin supply hole of the mold.

[Work]

When the molten resin is injected from the nozzle of the injection device, the molten resin is heated by the heater, passes through the resin passage of the runner body and the hole of the chip, and is supplied from the resin supply hole into the cavity of the die for molding. Be seen. The thermal expansion of the runner main body is absorbed by the spring, and the swing end surface of the runner main body is pressed against the rotatable roller, so there is little wear of the roller and the runner main body. It is easy to adjust even if it wears due to long-term use.

〔Example〕

1 to 3 show one embodiment of a hot runner according to the present invention, FIG. 1 is a partially cutaway front view thereof, and FIG. 2 is a partially cutaway II plan view of FIG. The figure is a front view as seen from III in FIG. In these figures, reference numeral 1 denotes a nozzle mounted on the tip of the barrel 2 of the injection device.
Is formed so as to advance and retreat in the axial direction indicated by the arrow A in FIG. 1 together with the barrel 2 and the like. The heater mounted on the peripheral surface of the barrel 2 and the screw in the barrel 2 heat and melt the inside of the barrel 2. The transferred resin is configured to be ejected from the nozzle 1. Reference numeral 3 denotes a lower die fixed to the stationary platen 4 via a die mounting plate 5, and this lower die 3 and a plate 7 fixed to the die mounting plate 5 via a support plate 6. A resin supply hole 8 that communicates with a cavity provided in the lower mold 3 and an upper mold (not shown) is formed in and.

A hot runner, generally designated by 10, is arranged between the nozzle 1 of the injection device and the resin supply hole 8 of the lower mold 3. The hot runner 10 is a pair of brackets fixed to the side surface 5a of the mold mounting plate 5 close to the nozzle 1.
Each bracket 11 has a bearing 12 fixed thereto. Reference numeral 13 denotes a trunnion formed of a rectangular plate-shaped support plate 13a and short shafts 13b projecting from both side surfaces thereof, and is rotatably supported by a bearing 12 via a bush 14. A small-diameter portion 13b formed at one end of the runner body, which is indicated by the whole numeral 15, is slidably and slidably inserted into the hole formed in the support plate 13a. The runner main body 15 is engaged with a groove 5b formed in the die mounting plate 5 and extends toward the resin supply hole 7, and a plurality of heaters 16 are mounted on the outer periphery thereof. 17 is a bracket fixed to the bottom surface 5c of the groove 5b.
A roller 18 is attached to the swing end surface of the runner body 15
Is rotatably pivoted via a pin 19, and
Between the base end step portion of the runner body 15 and the trunnion 13, for example, a disc spring 20 as a spring in which a spring force for pressing the swing end surface of the runner body 15 against the roller 18 is accumulated,
It is fixed by a nut 21 that is screwed into the threaded portion. When the nozzle 1 is moved forward, the nozzle 1 is pressed against the arc surface of the adapter 22 attached to the base end of the runner body 15.

A hydraulic cylinder 24 as a fluid pressure cylinder is supported by a bracket 23, which is located below the swinging end of the runner body 15 and fixed to the stationary platen 4, and the piston rod 25 that moves forward and backward by the hydraulic cylinder 24 is , The pin 26 is formed to be bendable, and the plate-like portion 25a formed at the working end of the piston rod 25 is provided at a plurality of plate-like portions 27 formed on the lower surface of the swing end of the runner body 15. It is fixed with bolts 28. A tip 29, which is concentric with the resin supply hole 8, is mounted on the upper surface of the swing end of the runner body 15. By raising the piston rod 25 of the hydraulic cylinder 24, the roller 18 whose end surface is in pressure contact is rotated. The runner body 15 swings while moving,
The chip 29 is configured to be bonded to the resin supply hole 8. 15a penetrates the shaft core of the runner body 15 and the adapter 22
This is a resin passage for communicating the hole of the chip with the hole of the chip 29. In addition, the bracket 30 supported on the lower end of the hydraulic cylinder 24
An ascending limit confirming limit switch 31 and a descending limit confirming limit switch 32 are fixed to the shaft, and strikers 33 and 34 are fixed to the downward protruding portion of the piston rod 25. By doing so, the upper limit and the lower limit of the piston rod 25 are confirmed.
A reference numeral 35 in FIG. 2 is a shim which is inserted between the bracket 11 and the side surface 5a of the mold mounting plate 5 to adjust the swing center of the runner body 15.

The operation of the hot runner configured as above will be described. When the barrel 2 is advanced to join the nozzle 1 to the hole of the adapter 22 and the hydraulic cylinder 24 is operated to move the piston rod 25 forward by the hydraulic pressure, the piston rod
While the runner body 15 fixed to the working end of 25 slides the swing end face against the roller 18 and rotates the runner body 15, the trunnion 13
The chip 29 is pressed into contact with the resin supply hole 8 by swinging around. When swinging the runner body 15,
Since 25 is bent, even if the plate-like portions 25a and 27 are fixed, the runner body can be smoothly rocked without any trouble. Also,
Since the swing end surface of the runner body 15 is pressed against the rotating roller 18, the swing end surface and the roller 18 are not worn. When the chip 29 is joined to the resin supply hole 8, the striker 33 contacts the limit switch 31 and the rising limit is confirmed.

After that, when the resin is supplied from the hopper of the injection device and the screw is rotated, the resin is melted and injected from the nozzle 1. This molten resin is contained in the resin passage 15b and the chip 29.
After being injected into the cavity of the mold through the resin supply hole 8 and is solidified, a molded product is obtained.

When the runner main body 15 thermally expands, its swinging end face moves toward the roller 18
Since it is pressed against and is restricted from moving to the left in the figure,
The runner body 15 extends to the right in the figure so as to compress the disc spring 20, and thermal expansion is absorbed by the disc spring 20. Therefore, the core of the chip 29 and the core of the resin supply hole 8 do not get out of alignment.

In this embodiment, the swinging end surface of the roller body 15 is connected to the roller 18
Although the disc spring 20 is illustrated as the spring to be pressed against, the invention is not limited to this, and may be a coil spring or a leaf spring, for example.

〔The invention's effect〕

As is clear from the above description, in the present invention, in the hot runner of the injection molding machine, the runner main body whose base end is swingably supported by the bearing near the resin injection nozzle via the trunnion is used as the resin of the mold. Extending so that the swing end is located below the supply hole, a roller on the machine stand side is attached to the swing end surface of this runner body, and the swing is performed by a disc spring provided at the base end of the runner body. While the end surface is pressed against the roller, a fluid pressure cylinder is provided below the swinging end of the runner body, and the working end of the bendable piston rod is fixed to the lower surface of the runner body to raise the piston rod. Thus, the tip provided on the swing end of the runner body is pressed into contact with the resin supply hole of the mold, so that the piston rod bends when swinging the runner body. Even if the rod end and the swing end of the runner body are fixed, the runner body does not interfere with the swing and smoothly swings, and the tip is correctly joined to the resin supply hole of the mold to ensure smooth resin supply. Done. Further, since the swing end surface of the runner body is pressed against the rotating roller, the swing end surface and the roller are not worn, and the durability is improved. Further, when the runner main body thermally expands, its swing end face is pressed against the roller and its movement in the swing end direction is restricted, so that the runner main body extends toward the base end portion so as to compress the spring. Since the thermal expansion is absorbed by the spring, the hole core of the chip and the hole core of the resin supply hole are correctly aligned, and the resin can be smoothly supplied.

[Brief description of drawings]

1 to 3 show one embodiment of a hot runner according to the present invention, FIG. 1 is a partially cutaway front view thereof, and FIG. 2 is a partially cutaway II plan view of FIG. The figure is a front view as seen from III in FIG. 1 ... Nozzle, 3 ... Lower mold, 8 ... Resin supply hole, 10 ...
… Hot runner, 11 …… Bracket, 12 …… Bearing, 13…
… Trunnion, 15… Runner body, 16… Heater, 18…
… Rollers, 20 …… disc springs, 21 …… nuts, 24 …… hydraulic cylinders, 25 …… piston rods, 26 …… pins, 29 …… chips.

Claims (1)

[Claims] 1. A bearing which is fixed in the vicinity of a nozzle of an injection device so as to be movable in the axial direction of the nozzle and adjustable, a trunnion rotatably supported by the bearing, and a base end of a hole of the trunnion. Part of the runner body which is inserted into the runner body and is oscillatably supported so that the tip of the swing end portion is located below the resin supply hole of the mold and is extended. A roller pivotally mounted on the base side, a spring interposed between the base end step of the runner body and the trunnion, and biasing the runner body in a direction in which the runner body is pressed against the roller; A hot runner for an injection molding machine, characterized in that a fluid pressure cylinder having a piston rod formed below the swinging end of the main body and formed to be bendable is fixed to the lower surface of the runner main body.