JPH04111957A - Feeder head rod device for injection forming apparatus - Google Patents

Abstract

PURPOSE:To miniaturize the whole apparatus by penetrating a magnetostrictive line rod into hole in a piston, embedding a magnet at some interval with this and fixing displacing sensor at bottom plate of a cylinder. CONSTITUTION:A piston rod 24 is extended to die direction from the piston 22 advanced/retreated in cylinder part 21 in the feeder head cylinder 25. A feeder head rod 29 as freely inserting into molten metal in the die cavity 13, is connected with this as the same axis. The magnetostrictive line rod 40 fixing the basis end part to the bottom face of cylinder part 21 and penetrating the hole of piston 22 and parallel extending with the piston rod 24, is arranged. The magnet 41 is embedded in the hole in the piston 22 at some interval with the magnetostrictive line rod 40. The displacement sensor 38 is fixed to the bottom plate 21c of cylinder. By this method, the necessary strength can be held even if thin material is used.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an injection molding apparatus that injects a molten material into a mold cavity to mold a molded product. The invention relates to a feeder rod device that pressurizes the feeder.

[Conventional technology]

For example, JP-A-61-140747, which has been proposed as this type of injection molding apparatus, discloses a mold opening/closing unit for a rotary die casting machine for casting automobile disc wheels made of aluminum, etc. It is structured as follows. That is, an upper mold is provided above the lower mold fixed on the mounting plate, and is supported by a top plate that is raised and lowered by a mold opening/closing cylinder erected on the mounting plate. For example, four cores are provided between the molds and are driven by cylinders and move forward and backward in the radial direction. A cavity is formed between the clamped upper and lower molds and the closed core, and a fixed sleeve with an inner hole that communicates with the cavity is located in the center of the lower mold. It is fitted through the hole in the mounting plate.

With this structure, the mold opening/closing unit is supplied onto the rotary table, the rotary table is rotated, and after stopping at the injection station and clamping the mold, the injection sleeve is joined to the fixed sleeve and injection is performed. When the molten metal pressed by the injection cylinder on the station side is injected into the cavity through the injection and fixation sleeve, it solidifies and a product is obtained. After this, the mold is opened and the product is taken out.

In such die-casting machines, the molten metal may not spread to every corner of the cavity, which reduces the quality of the product, so the die opening/closing unit is equipped with a feeder rod that moves into and out of the cavity using a drive device. This feeder is opened just before or after the molten metal is injected into the cavity.

Since the molten metal is pushed by entering the drum cavity, the molten metal spreads to every corner of the cavity, and a dense product can be obtained.

In a feeder rod device that operates in this way, the stroke, which is the advance position of the feeder rod with respect to the start time of the feeder, the speed of the feeder rod at each point from the start of the feeder to the end of the feeder, and time is determined by the product. Since this affects the quality of the product, a control device is required to control this.

As this type of control device, it is conceivable that a transmission source is buried in the outer circumferential surface of the piston of the riser cylinder, and a corresponding receiving source is provided across the outer wall of the cylinder to control the transmission source.

[Problem to be Solved by the Invention J] However, in such a control device, the outer wall of the cylinder interposed between the source that transmits the pulse and the receiving source that receives the pulse is made of a material such as AI, Zn, Pb, Sn, C
It is necessary to use a non-magnetic material such as u, and if you want to ensure strength, it is necessary to use non-magnetic steel such as Mn, Cr, Ni, which has high stress.
It is necessary to use steel with a stenite structure that contains a considerable amount of carbon dioxide, etc., and in this type of magnetic detection method from the outside of the cylinder, there is a problem that the material is limited to special steel. Further, although it is possible to detect only one predetermined position of the piston, it is difficult to detect a position that changes every moment. Furthermore, it is necessary to provide the receiving source outside the cylinder, which increases the size of the device, and since it is necessary to provide the transmitting source on the outer circumferential surface of the piston, a seal between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder is required. The problem is that it becomes uncertain.

The present invention has been made in view of the above points, and an object of the present invention is to provide a feeder rod device for an injection molding machine that has a compact configuration and enables the position control of a piston.

[Means to solve the problem]

The present invention aims to achieve such an objective.

A piston loft extending toward the mold from a piston that advances and retreats within the cylinder portion of the feeder cylinder is connected to a feeder rod that is removably inserted into the molten material in the mold cavity. A magnetostrictive wire rod whose base end is fixed to the bottom surface passes through the hole of the piston and extends parallel to the piston loft, a magnet embedded in the hole of the piston with a space between the magnetostrictive wire rod, and a displacement sensor connected to the wire rod and fixed to the bottom plate of the cylinder.

[For production]

When the melt is filled into the mold cavity and the melt is supplied to the rear of the piston of the feeder cylinder just before or after it begins to solidify, the feeder rod of the feeder cylinder's piston rond moves forward and its tip ends. As it enters the melt in the cavity, the molten material is pushed to every corner of the cavity.

During the feeder, the cooling water supplied from the water supply port into the cooling pipe is turned around at the tip of the feeder rod, passes through the cooling water passage, and is discharged from the drain port, so the piston loft and feeder rod are cooled during this time. be done.

When the feeder rod moves, the magnet integrated with the piston moves relative to the stationary magnetostrictive wire rod, causing torsional strain on the magnetostrictive wire rod.A displacement sensor measures this propagation time, and the movement of the piston is detected. can be controlled.

〔Example〕

1 and 2 show an example in which the feeder rod device of an injection molding machine according to the present invention is implemented in a mold opening/closing unit of a rotary die casting machine, and FIG. 1 is a longitudinal sectional view of the feeder rod device, and FIG. Figure 2 is a cross-sectional view of a mold opening/closing unit that implements this method. In the figure, the rotary die-casting machine is equipped with a rotary die-casting machine (not shown) and three mold opening/closing units l supplied and mounted at positions that divide the outer periphery into three equal parts in the circumferential direction. Three work stations are respectively provided at the stop positions of the mold opening/closing unit, which rotates intermittently through 120 degrees and stops after completing 120 degrees. The winter type opening/closing unit 1 is equipped with a mold to be described later, and each of the three work stations performs mold clamping and injection, mold opening and product ejection, mold cleaning and mold cleaning for the winter type opening/closing unit. The mold release agent is sprayed, and one cycle is completed by one rotation of the rotary table. The figures show the mold opening/closing unit stopped at the mold clamping and injection stations, respectively, and a mold clamping device and an injection device (not shown) are disposed above and below FIG. 2, respectively.

In the figure, a mold opening/closing unit 1 includes a mounting plate 2 fixed on a rotary table (not shown), and pistons that are raised and lowered by hydraulic pressure of a pair of mold opening/closing cylinders 3 erected on both left and right sides of the mounting plate 2. A horizontal plate-like top plate 5 is fixedly supported at the working end of the rod 4. As the screws 1 to 4 move forward and backward, the top plate 5 and an upper mold 6, which will be described later, are moved up and down, thereby opening and matching the molds. A lower mold 7 is fixed to the mounting plate 2, and the lower mold 7 is disassembled and joined into a substrate 7a, a side plate 7b, a spacer 7c, and an injection molding 97d. The fixed sleeve 8 is fitted.

On the other hand, the drum-shaped upper mold 6 fixed to the lower surface of the top plate 5 includes a concave hole 6a that opens upward and has a square cross section, and a protrusion 6b that protrudes downward from the center of the lower end surface. Further, around the protrusion 6b, a core 9 divided into a plurality of parts in the circumferential direction is supported by a piston rod 12 of a core cylinder 11 supported by the upper mold 5 via a support plate 10. It is provided. A lower mold 7, an upper mold 6 clamped thereto, and a closed cavity 13 for the core 9 are formed. On the other hand, the injection sleeve 1 on the injection cylinder side (not shown) is attached to the fixed sleeve 8.
4 are removably joined, and this injection sleeve 14
After supplying the molten metal 15 to the molten metal 15, by moving the plunger 16 forward, the molten metal 15 passes through the runner 17 and enters the cavity 13.
It is configured to be ejected inward.

Next, a feeder rod device according to the present invention housed in the square recessed hole 6a of the upper mold 6 will be explained. The feeder rod device, which is designated as a whole by the reference numeral 20, has a cylinder portion that includes a main body 21a that is formed into a rectangular tube shape with a bottom and is fitted into a recessed hole 6a and is fixed, and a lid body 21b that closes the lower end opening of the main body 21a. 21, a piston 22 that is slidably fitted into the inner hole 21c of this cylinder portion 21, a rear piston rod 23 whose flange portion is bolted to the piston 22 and extends rearward, and a front portion that extends forward from the piston 22. It is provided with a feeder cylinder 25 of piston type on both sides formed by a piston rod 24, and the front piston rod 24 is slidably supported by a bearing 26 bolted to the lid 21b. Among the members constituting the riser cylinder 25,
The bottom plate 21c of the cylinder portion 21 is provided with an oil inlet/outlet 21d and an annular groove 21e communicating with the oil inlet/outlet 21d. Further, a guide rod 27 formed in a hollow tube shape and fixed to the bottom plate 21c of the cylinder portion 21 is slidably fitted into a plurality of round holes 22a provided at equal positions in the circumferential direction of the piston 22. The distal end of the guide rod 27 is engaged with a recessed hole 21f provided in the lid 21b of the cylinder portion 21, and the inside of the distal end of the guide rod 27 formed in the shape of a hollow tube is connected to the cylinder. An oil inlet/outlet 21g is provided at the upper end of the guide rod 27 and communicates with the front chamber of the kite rod 21. It is configured.

In addition, when the inside of the tip part of the tubular guide rod 27 is communicated with the front chamber of the cylinder part 21, as shown in FIG. Alternatively, the distal end surface of the guide rod 27 may be brought into contact with the bottom plane of the recessed hole 21f, and a lateral groove or a lateral hole may be provided in the peripheral wall surface of the distal end portion of the guide rod 27.

In this case, the guide rod 27 has the role of a guide for the movement of the piston 22, a role of preventing rotation of the cylinder 22, and a role of letting hydraulic oil into and out of the front chamber of the cylinder portion 21.

Furthermore, a male threaded part 28a of a joint 28 is screwed into a female threaded part formed at the lower end of the front piston rod 24, and the other male threaded part 28b of the joint 28 is threaded into a female threaded part 28a of a joint 28. It is screwed together with the neck. The feeder rod 29 is inserted into and removed from the cavity 13 by supplying oil above or below the piston 22 and moving the piston 22 of the feeder cylinder 25 back and forth. The end surface of the riser rod 29 may be formed into an arc shape as shown in FIG. 1, or may be formed into an inverted cylindrical shape. Further, by rotating the joint 28, the overall length of the rear piston rod 24 and feeder rod 29, which are connected to the joint 28 by a threading action, can be adjusted. The hole 21h formed in the bottom plate 2]c of the cylinder portion 21 has recesses 30a and 30b.
In plan view, the square block 30 has a protrusion 3.
The bottom plate 21c and the block 30 are fixed with a plurality of pins 30g. block 3
The upper end surface of 0 is flush with the upper end surface of the upper mold 6,
It is provided in contact with the lower surface of the top plate 5. As a result, even if there is a concave hole 6a for installing the feeder rod device 20 in the upper mold 6, the strength of this portion is sufficiently maintained.

This block 30 is provided with a water supply port 30d and a drain port 30e which are connected to a cooling water source (not shown) via piping, and the rear piston rod 23 is connected to a space 30f provided in the block 30. In addition to being involved in
The drain port 30e communicates with the space 30f. 31
is a cooling pipe communicating with the water supply port 30d, and this cooling pipe 31 runs from the block 30 at the upper end of the device to the rear piston rod F23. Piston 22. It extends through the axial center of the member through the front piston rod 24 and joint 28 to the feeder rod 29 at the lower end of the device, and its lower end is inserted into the inner hole 29a of the feeder rod 29. It is opened. Piston 22. Between the front piston rod 24 and the cooling pipe 31, a cooling water passage 32 is formed in an upper and lower annular groove 3.
A cooling water passage 35 is provided between the joint 28 and the cooling pipe 31 so that the upper and lower annular grooves 34 and 36 communicate with each other. Further, the space portion 30f and the annular groove 33 are communicated with each other through a cooling water passage 37. By doing this, the cooling water supplied from the water supply port 30d passes through the inside of the cooling pipe 31, reaches the inner hole 29a of the feeder rod 29, makes a U-turn, and is drained through the cooling water passages 35 and 32°37. The water is discharged from the port 30e, and the feeder rod 29, front piston wand 24, etc. are cooled by the cooling water during this time. Note that the cooling pipe 31 is divided in the axial direction at a dividing surface 31a. Note that the cooling pipe 31 may be a single pipe, or may be a double pipe of a sliding type so that the length can be adjusted.

Furthermore, the device is provided with a control device for controlling the movement of the riser rod 29. That is, the displacement sensor 38 is mounted on the bottom plate 21c of the cylinder portion 21, and the displacement sensor 38 is attached to the threaded portion 38a.
The displacement sensor 38 is fixed by being screwed into the screw hole 21j, and the displacement sensor 38 is connected to a control device (not shown) by a lead wire 39.

In this control device, feeder rod 29 against time
The forward stroke position of the riser rod 29 is set so as to form a predetermined curved line, and the detected value of the forward stroke position of the riser rod 29 with respect to time detected by the displacement sensor 38 is compared with the set value every moment. By performing feedback control based on the deviation signal and controlling the supply amount and pressure of pressure hydraulic oil supplied to the rear chamber of the cylinder section 21, the forward stroke position of the riser rod 29 can be controlled to match the set value. . Also, a displacement sensor 3 is attached to the piston 22.
A magnetostrictive wire rod 40 whose base end is fixed to the bottom plate 21c and is parallel to the guide rod 27 is inserted into the through hole 22b concentrically with the displacement sensor 38, and is inserted concentrically with the displacement sensor 38. The chamfered tip of the magnetostrictive wire rod 40 is engaged with the recessed hole 21f of the lid 21b. Further, at the upper end of the piston 22, there is an annular magnet 41 that is concentric with the magnetostrictive rod 40 and has an inner diameter slightly larger than its outer diameter.
is buried, and this magnet 41 is prevented from coming off from the piston 22 by a port 42 and a one-shaft 43. The magnet 41 moves with the piston 22 as it advances and retreats in the axial direction, and the magnetostrictive wire rod 40 remains stationary. The structure is configured such that the relative position with respect to the and,
When a current pulse in the axial direction is applied to the magnetostrictive wire rod 40,
A magnetic field in the circumferential direction is generated in the magnetostrictive wire rod 40, and a magnetic field in the axial direction is generated in the magnet 41. A magnetic field is generated and torsion is generated at this location, so this torsion becomes vibration and ultrasonic waves propagate at the speed of sound on the magnetostrictive wire rod 40, and the displacement sensor 3
8 measures the propagation time of this ultrasonic wave, thereby making it possible to measure the position of the magnet 41, and as a result, the position of the piston, and therefore of course the position of the riser rod 29, can be detected. , the forward movement of the riser rod 29 is controlled via a control device by a signal generated by converting this position into an analog electrical signal.
There is.

In FIG. 2, extrusion cylinders 44 are fixed to the top plate 5 on both sides of the feeder rod device 20, and the tip of the piston rod 45 faces the upper end of the cavity 13. The product in the cavity 13 is extruded by operating the cylinder 44.

The operation of the injection molding machine configured as above will be explained.

After being sprayed with molding agent at the upstream work station, the mold opening/closing unit 1-1, which is mold-aligned by retracting the piston rod 4 of the mold opening/closing cylinder 3 with the core 9 closed, rotates. As the table rotates, it revolves around the mold clamping and injection station, stops, and is clamped by the mold clamping cylinder. Next, the injection sleeve 14 into which the molten metal 15 has been injected is joined to the fixed sleeve 8, and as the plunger 16 of the injection cylinder moves forward, the molten metal 15 is injected into the cavity 13 through the runner 17. Molten metal 15
Since oil is supplied from the oil inlet/outlet 21d immediately before or after the molten metal 15 finishes filling into the cavity 13, that is, before the molten metal 15 begins to solidify, the piston 22, the upper and lower piston rods 23, 24, and the riser rod 29 are integrated. descends to
The tip of the feeder rod 29 is connected to the molten metal 15 in the cavity 13.
inserted into. As a result, a part of the molten metal 15 in the cavity 13 is removed and flows into the cavity 13 to act as a feeder, so that the molten metal 15 reaches every corner of the cavity 13. In this state, the molten metal 15 begins to solidify, and after a predetermined period of time, the solidification is completed and a product is obtained. Therefore, when oil is supplied from the oil inlet/outlet 21g, this oil is transferred to the guide rod 27.
is supplied to the lower side of the piston 22 through the inner hole of the
The piston 22 rises and the riser lot 29 enters the cavity 1.
Removed from 3. After that, when the rotary table rotates 120 degrees and the mold opening/closing unit 1 stops at the product removal station, the piston rod 4 of the mold opening/closing cylinder 3 moves forward and the top plate 5 rises, so the mold is opened and The core 9 is opened and the extrusion cylinder 42 is actuated so that the product is pushed by the extrusion bin 43 and removed from the cavity 13.

During such casting operation, cooling water is supplied from the water supply port 30d, and this cooling water passes through the inner hole of the cooling pipe 31 and is discharged into the inner hole 29a of the riser rod 29, and then flows into the annular shape. It enters the cooling passage 35 from the groove 36, passes through the annular groove 34, the cooling water passage 32, the annular groove 33, and the cooling water passage 37, and is discharged from the drain port 30e. Since 23 and 24 are cooled, they are not altered or damaged. Further, since the downward movement of the feeder rod 29 is controlled by the control device via the detection rod 40 and the displacement sensor 38, the operation of the feeder rod 29 is automatically stabilized, and the molding conditions are stabilized.

Furthermore, when a current pulse in the axial direction is applied to the magnetostrictive wire rod 40 during the feeder operation, a magnetic field in the circumferential direction is generated in the magnetostrictive wire rod 40, and a magnetic field in the axial direction is generated in the magnet 41. In the magnet 4I corresponding part of 40, a magnetic field in an oblique direction, which is the composite direction of the axial direction and the circumferential direction, is generated and twisting occurs at this location, so this twisting becomes vibration and the ultrasonic wave becomes magnetostrictive. The ultrasonic wave propagates on the wire conductor 40 at the speed of sound, and the displacement sensor 38 measures the propagation time of this ultrasonic wave and calculates the signal emitted by the signal to determine the position of the magnet 41 and, ultimately, the forward position of the riser rod 29, The detected value of the lever is compared every moment with the set value of the forward stroke of the feeder rod 29 with respect to time, and feed bank control is performed based on the deviation signal, thereby controlling the movement of the feeder rod 29, particularly the forward position with respect to time. In this case, the magnetostrictive wire rod 40 and the magnet 41 are connected to the cylinder part 21.
Since the cylinder portion 21 is housed inside the cylinder portion 21, the device does not become large-sized, and there is no need to use a non-magnetic material for the cylinder portion 21.

Although this embodiment shows an example in which the present invention is applied to a rotary die-casting machine, it goes without saying that the present invention can also be applied to a stationary die-casting machine, and can also be applied to a plastic injection molding machine. be able to.

〔Effect of the invention〕

As is clear from the above description, in the feeder rod device of an injection molding machine according to the present invention, the piston rod extends from the piston that advances and retreats within the cylinder portion of the feeder cylinder toward the mold, and is concentrically connected to the mold. A feeder rod which is inserted into and removed from the melt in the cavity is connected to the feeder rod, and a magnetostrictive wire rod whose base end is fixed to the bottom of the cylinder part and extends parallel to the piston rod through the hole of the piston. A magnet is embedded in the hole of the piston at a distance from the magnetostrictive wire rod, and a displacement sensor is connected to the magnetostrictive wire rod and fixed to the bottom plate of the cylinder. The magnet is moved in the axial direction relative to the stationary magnetostrictive wire rod, and the ultrasonic waves generated by the torsional vibration generated in the magnetostrictive wire rod are propagated to a displacement sensor to determine the position of the magnet and feeder rod. By detecting this and controlling the movement of the feeder rod via the control device, the control device is housed within the cylinder, making the entire device smaller than conventional devices, making it more compact. In addition, the cylinder does not need to be made of non-magnetic material as in the past, and if the outer peripheral wall of the cylinder is made of a material such as high-strength special steel, the required strength can be achieved even with a thin material. The device can be further miniaturized.

[Brief explanation of the drawing]

1 and 2 show an example in which the feeder rod device of an injection molding machine according to the present invention is implemented in a mold opening/closing unit of a rotary die casting machine, and FIG. 1 is a longitudinal sectional view of the feeder rod device, and FIG. The figure is a longitudinal sectional view of a mold opening/closing unit that implements this. 1... Mold opening/closing unit 7), 6... Upper mold, 7...
... lower mold, 13 ... cavity, 15 ... molten metal, 20 ... feeder rod device, 21 ... cylinder section, 22 ... piston, 24 ... Front piston rod, 25... riser cylinder, 38... displacement sensor, 40... magnetostrictive wire rod, 41... magnet. Patent applicant: Ube Industries, Ltd.

Claims (1)

[Claims] A feeder rod is connected to a piston rod that extends in the direction of the mold from a piston that moves forward and backward within the cylinder portion of the feeder cylinder, and that is coaxial with the piston rod and is inserted into and removed from the melt in the mold cavity. A magnetostrictive wire rod whose base end is fixed to the bottom surface of the piston and extends parallel to the piston rod through the hole of the piston, and a magnetostrictive wire rod embedded in the hole of the piston with a space between the magnetostrictive wire rod and the magnetostrictive wire rod. A feeder rod device for an injection molding apparatus, comprising a magnet and a displacement sensor connected to the magnetostrictive wire rod and fixed to the bottom plate of the cylinder.