JP2001328139A - Fluid jet nozzle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid jet nozzle device capable of stably ejecting a fluid and capable of achieving miniaturization, cost reduction and energy saving. SOLUTION: In the fluid jet nozzle device wherein the fluid flowing in the jet hole of a nozzle main body is ejected from the jet orifice provided to the leading end of the jet hole under predetermined pressure, the induction heating coil connected to a transistor inverter is arranged to the nozzle main body and the flux density by the induction heating coil is set so as to be different along the flow direction of the fluid flowing through the jet hole. A plurality of the induction coils are arranged along the flow direction of the fluid or the induction heating coil is changed in its winding pitch along the flow direction of the fluid to set different flux densities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle device provided in, for example, an injection molding machine, and more particularly to a nozzle device for jetting a fluid which can stably jet a fluid at a predetermined pressure.

[0002]

2. Description of the Related Art Conventionally, a metal injection molding machine, a rubber injection molding machine and the like are provided with a nozzle device for injecting a fluid such as metal or rubber into a cavity of a mold. And
As this nozzle device, for example, JP-A-11-3004
As disclosed in Japanese Patent Application Laid-Open No. 62-34034 and Japanese Patent Application Laid-Open No. 8-34034, there is known a nozzle device in which an induction heating coil is arranged on the outer peripheral surface of the tip end portion.

[0003]

However, in these nozzle devices, an induction heating coil wound at a constant pitch is arranged on the outer peripheral surface of the tip portion of the nozzle device, and flows through the nozzle device. There is a problem that it is difficult to stably inject the fluid since the incoming fluid is simply heated up to the injection temperature and injected.

That is, since the fluid flowing into the nozzle device is ejected from the small-diameter injection port at a high pressure, it is difficult to control the heating speed more stably than the injection speed due to this pressure. As a result, it is difficult to stably inject the fluid, for example, the injection pressure tends to be uneven. In addition, in order to perform rapid heating at a speed higher than the injection speed, a high-output induction heating device is required, which tends to increase the size and cost of the device itself, and increase power consumption, making it difficult to save energy. There was also.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is capable of stably injecting a fluid, reducing the size and cost of the device, and achieving energy saving. Is to provide.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a fluid flowing into an injection hole of a nozzle body is provided at an end of the injection hole. A nozzle device for injecting fluid at a predetermined pressure from the nozzle body, the nozzle body is provided with an induction heating coil connected to a transistor inverter, and the magnetic flux density of the induction heating coil is applied to the fluid flowing through the injection hole. It is characterized in that it is set differently along the flow direction.

With this configuration, the fluid flowing into the injection hole of the nozzle body is based on the magnetic flux of the induction heating coil disposed along the longitudinal direction of the injection hole (the flow direction of the fluid). It is injected from the injection port at the tip of the injection hole while being induction heated. At this time, since the magnetic flux density generated from the induction heating coil is set so that, for example, the downstream orifice side is high and the upstream side is low, the fluid is injected while being gradually heated during the flow. . Thereby, the heating condition of the fluid at the injection port portion is made uniform, and a stable injection state is obtained. In addition, the induction heating coil arranged so that the magnetic flux density is different eliminates the need for local rapid heating, which reduces the output of the transistor inverter and reduces the size and cost of the device. Power can be saved.

According to a second aspect of the present invention, a plurality of the induction heating coils are arranged along a flowing direction of the fluid so that the magnetic flux densities are set differently. The invention described in Item 3 is characterized in that the magnetic flux density is set to be different by changing the winding pitch of the induction heating coil along the flowing direction of the fluid. With this configuration, the magnetic flux density can be varied by arranging a plurality of induction heating coils or changing the winding pitch of the coils, so that the configuration of the coil itself is simplified and the device becomes more compact. And cost reduction.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of a nozzle device for ejecting a fluid according to the present invention. In FIG. 1, a nozzle device 1 has a nozzle body 2 having an injection hole 3 formed therein.
For example, a magnetic material of an iron-based metal is formed in a substantially tubular shape having a large-diameter portion 2a, a small-diameter portion 2b, and an inclined portion 2c. The mouth 3a is formed.

Further, induction heating coils 4 and 5 are arranged on the outer peripheral surfaces of the large-diameter portion 2a and the small-diameter portion 2b of the nozzle body 2 in a fitted state. The induction heating coils 4 and 5 are formed, for example, by winding a copper pipe 6 by a predetermined number of turns and covering the periphery thereof with a heat-resistant member 7 such as a ceramic. Are connected to the output terminals. The cable 8 electrically connects the induction heating coils 4 and 5 to the transistor inverter 9 and cools a cooling machine (not shown) provided integrally (or separately) with the transistor inverter 9. Water is supplied to induction heating coils 4 and 5
Cable 8 of an appropriate structure capable of being circulated and supplied in copper pipe 6
Is used.

The induction heating coils 4 and 5 are set so that the winding pitch p of the copper pipe 6 is substantially constant, and the number of turns n of the coils 4 and 5 is different.
Further, the induction heating coil 4 and the induction heating coil 5 are arranged on the outer peripheral surface of the nozzle body 2 with a predetermined interval P.
Due to the pair of induction heating coils 4, 5, the magnetic flux density generated from both coils 4, 5 is reduced by the injection holes 3 of the nozzle body 2.
In the longitudinal direction (flow direction of the fluid R), the small-diameter portion 2b on the downstream side is high, and the inclined portion 2c on the immediately upstream side
The portion is low, and the large-diameter portion 2a on the upstream side is high, that is, the fluid R is set to flow smoothly in the flow direction.

The transistor inverter 9 has an inverter circuit using a semiconductor switching element such as a MOSFET or IGBT (not shown), an output transformer (current transformer), and the like, and outputs a high-frequency current having a predetermined output of several KHz to several MHz. , And induction heating coils 4 and 5. The operation of the transistor inverter 9 is controlled by, for example, a control signal of a control device 10 for controlling an injection molding machine.

Next, an example of the operation of the nozzle device 1 will be described. First, the nozzle device 1 is mounted on an injection molding machine (not shown), and is set by bringing the tip of the small diameter portion 2b of the nozzle body 2 into close contact with the injection hole 11a of the mold 11, and At the same time as the operation of the injection molding machine, the transistor inverter 9 also operates, and a high-frequency current is supplied to the induction heating coils 4 and 5. When a high-frequency current is supplied to the induction heating coils 4 and 5, an eddy current is induced in the nozzle body 2 made of a magnetic material by the magnetic flux generated from the coils 4 and 5, and the nozzle body 2 is induction-heated to a predetermined temperature. .

When the nozzle body 2 is induction-heated, the fluid R such as metal or rubber (resin) flowing into the injection hole 3 of the body 2 is heated to a predetermined temperature. R flows downstream due to the pressure and is injected into the cavities 13 of the dies 11 and 12 from the injection port 3a of the nozzle body 2 at a predetermined pressure. At this time, since the magnetic flux densities of the induction heating coils 4 and 5 are set to be different along the flow direction of the fluid R, the fluid R flows smoothly in the injection hole 3 and has a predetermined pressure. Is injected from the injection port 3a.

As described above, according to the nozzle device 1 of the above embodiment, the pair of induction heating coils 4 and 5 are arranged on the outer peripheral surface of the nozzle body 2 along the longitudinal direction, and the induction heating coils 4 and 5 are arranged. Is varied along the flow direction of the fluid R, so that the temperature of the fluid R flowing in the injection hole 3 can be easily heated and maintained at an optimum temperature suitable for the flow. The body R can be injected from the injection port 3a in a stable state.

In particular, since a pair of induction heating coils 4 and 5 are arranged corresponding to the shapes of the large-diameter portion 2a, the inclined portion 2c and the small-diameter portion 2b of the nozzle body 2, the portion from the large inner diameter to the inner diameter is changed. It is possible to smoothly flow the fluid R flowing in a small portion, and to obtain a stable injection without variation and unevenness in the injection pressure, and as a result, it is possible to reduce a defective rate of a molded product. Become.

Further, as compared with the conventional example in which one induction heating coil is arranged at the injection port portion and the portion is rapidly heated, the fluid R is gradually heated from the upstream side in advance and the injection port 3 is heated.
Since the predetermined injection temperature (injection pressure) is set at the portion a, the control by the control device 10 is simplified, and the durability of the injection port 3a of the nozzle body 2 does not need to be significantly increased. Furthermore, since there is no need to rapidly heat the injection port 3a, the output of the transistor inverter 10 can be further reduced, and the size, cost, and power consumption of the device 1 itself can be reduced.

In the above embodiment, a pair of induction heating coils 4 and 5 having a substantially constant winding pitch are arranged in the longitudinal direction of the injection hole 3 of the nozzle body 2 so that the magnetic flux in the flow direction of the fluid R is changed. Although the density is different, the present invention is not limited to this, and may be configured as shown in FIGS. 2 and 3, for example. That is, the nozzle device 1 shown in FIG. 2 generates a magnetic flux by changing the winding pitch of the pair of induction heating coils 4 and 5 so that the upstream side is coarse and the downstream side is dense for each coil 4 and 5. The density is different in the flow direction of the fluid R.

In the nozzle device 1 shown in FIG. 3, one induction heating coil 4 is disposed over the large-diameter portion 2a, the inclined portion 2c, and the small-diameter portion 2b of the nozzle body 2, and the winding of the induction heating coil 4 is performed. The pitch is set so that the upstream side is coarse and the downstream side is dense. As described above, the induction heating coil according to the present invention can adopt an appropriate shape and arrangement having different magnetic flux densities in the flow direction of the fluid R.

Further, in the above embodiment, the case where the magnetic flux density generated from the induction heating coils 4 and 5 is coarse on the upstream side and dense on the downstream side, for example, depending on the type of the fluid R, the magnetic flux density on the downstream side is high. The shape and arrangement of the induction heating coils 4 and 5 that are rough and dense on the upstream side can be adopted.
In short, the magnetic flux density differs in the flow direction of the fluid R,
An appropriate structure in which the fluid R is smoothly injected can be adopted.

In the above embodiment, the case where the nozzle device 1 is provided in the injection molding machine has been described.
It is needless to say that the present invention can be applied to a nozzle device for injecting various fluids, such as a nozzle device for injecting paint or a nozzle device for injecting fuel. In addition,
In the above embodiment, the induction heating coils 4 and 5 are fixedly arranged on the outer peripheral surface of the nozzle body 2. However, for example, the induction heating coils 4 and 5 are arranged in a buried state in the side wall of the nozzle body 2, The nozzle body 2 can be detachably disposed, and the shape of the nozzle body 2 can be appropriately changed.

[0022]

As described above in detail, according to the first aspect of the present invention, the magnetic flux density generated from the induction heating coil disposed in the nozzle body is set so as to be different along the flow direction of the fluid. As a result, the heating conditions of the fluid at the injection port are made uniform, a stable injection state can be easily obtained, and local rapid heating is not required. Thus, the size and cost of the apparatus can be reduced, and power can be saved.

According to the second or third aspect of the present invention, in addition to the effect of the first aspect of the present invention, the magnetic flux density can be reduced by arranging a plurality of induction heating coils or changing the winding pitch. Since the induction heating coil itself can be made different, the configuration of the induction heating coil itself can be simplified, and the size and cost of the device can be further reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a nozzle device for fluid injection according to the present invention.

FIG. 2 is a sectional view of a main part showing another embodiment of the nozzle device for fluid injection according to the present invention.

FIG. 3 is a cross-sectional view of a main part showing still another embodiment of the fluid injection nozzle device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle apparatus 2 Nozzle main body 2a Large diameter part 2b Small diameter part 3 Injection hole 3a Injection port 4, 5 Induction heating coil 6 Copper pipe 7 Heat resistant member 9 Transistor inverter 10 Control device 11, 12 Mold 13 Cavity

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H05B 6/44 H05B 6/44

Claims (3)

[Claims] 1. A fluid ejecting nozzle device for ejecting a fluid flowing into an injection hole of a nozzle body at a predetermined pressure from an injection port provided at a tip of the injection hole, wherein the nozzle body is connected to a transistor inverter. Wherein the induction heating coil is disposed and the magnetic flux density of the induction heating coil is set to be different along the flow direction of the fluid flowing in the injection hole. 2. The fluid injection device according to claim 1, wherein a plurality of the induction heating coils are arranged along a flowing direction of the fluid so that the magnetic flux densities are set differently. Nozzle device. 3. The flow according to claim 1, wherein the magnetic flux density is set to be different by changing a winding pitch of the induction heating coil along a flowing direction of the fluid. Nozzle device for body injection.