WO2010113745A1 - Ejector for die casting machine and method of controlling the same - Google Patents

Abstract

Provided is an ejector, simple in structure, for a die casting machine and a method of controlling the ejector capable of die-casting with high quality. The ejector for a die casting machine, wherein a plunger is pushed forward to eject molten metal contained in a sleeve, has an ejector provided with a plunger driven by a motor at a high and a low speed, a pressure mechanism for imparting a pressure on the molten metal by means of the plunger, and a shift lock mechanism for blocking the shift between the plunger and the pressure mechanism during the time when the molten metal is under pressure.

Description

Injection apparatus for die casting machine and control method therefor

The present invention relates to an injection device of a die casting machine which is used when casting an aluminum product and driven by a servo motor and a control method thereof.

First, a general die casting apparatus and method using a hydraulically driven horizontal die casting machine will be described with reference to FIG.
The die casting machine (casting apparatus) 1100 includes a mold apparatus 1101 and an injection apparatus 1102. A fixed mold 1118 and a movable mold 1119 are attached to the mold apparatus 1101 between the pair of opposed fixed platen 1120 and the movable platen 1121. The fixed mold 1118 and the movable mold 1119 are closed by a mold clamping device composed of a fixed platen 1120 and a movable platen 1121 to form a cavity (cavity) 1122 therebetween. A molten metal such as aluminum (AL) (a molten state at high temperature) is injected and filled in the cavity 1122 under a load of a mold clamping force, and the mold is opened and taken out after cooling and solidification to manufacture a cast molded article. it can. An injection device 1102 is provided to inject and charge the molten aluminum. Further, the stationary platen 1120 is provided with a plunger sleeve 1117 in which the molten aluminum is stored, and it passes through the stationary platen 1120 and the stationary mold 1118 and is distributed to the cavity 1122.

The injection device 1102 is provided with an injection cylinder provided with a hydraulically driven reciprocating piston / cylinder for injecting a molten aluminum. The injection cylinder comprises an injection cylinder body 1116 and a piston 1103. The piston 1103 engages a plunger sleeve 1117. Further, the piston 1103 has a piston head 1115 at the left end in FIG. 23, and a plunger rod 1112 is connected to a piston rod 1114 integrated with the piston head 1115 by an injection coupling 1113. 1111 is attached. The plunger tip 1111 fits in the plunger sleeve 1117, reciprocates in the plunger sleeve 1117, and pumps the molten aluminum in the plunger sleeve 1117 to inject and fill the molten aluminum in the cavity 1122. Do.
In the embodiment shown in FIG. 23, since the injection device 1102 is hydraulic, hydraulic fluid (not shown) is supplied to the head side of the cylinder body 1116 to drive the piston head 1115 and the piston rod 1114. Then, the molten aluminum (AL) stored in the plunger sleeve 1117 is pushed by the plunger tip 1111 and injected into the cavity 1122 formed by the fixed die 1118 and the movable die 1119 for casting.

Here, properly setting and controlling the injection speed and the injection pressure at the time of injecting and filling the molten metal into the cavity is extremely important for casting a non-defective product.
A general casting injection speed pattern will be described with reference to FIG.
In the hot water supply process before the injection filling process is started, the molten metal is poured into the injection sleeve 1117 by a hot water supply device (not shown), and an injection start state is established. The tip position of the plunger tip 1111 at this time is A (see the upper view of FIG. 24).

From this state, the low speed injection process is performed first. In this process, it is necessary to advance the plunger tip 1111 at a low speed so that the molten metal does not take in the corrugated air inside the injection sleeve 1117. Therefore, stable low speed (VL) control is required. When the plunger tip 1111 moves forward and the molten metal reaches the upper wall of the injection sleeve 1117 and further reaches the B position where the surface of the molten metal rises to the vicinity of the gate (when detecting that the injection stroke sensor advances SL) It is switched (see the second drawing from the top of FIG. 24).
In the high-speed injection process, the plunger tip 1111 and the like are accelerated at once, and the molten metal is injected and filled into the cavity 1122 at high speed (Vh). This is because the molten metal instantaneously solidifies when coming into contact with the surface of the cavity 1122 which is at a low temperature, and it is desirable for the casting of a non-defective product to be filled before solidifying in as short a time as possible. In particular, as the size and complexity of the cavity 1122 (cast product) increases, higher speed is required.
Then, immediately before the molten metal is completely filled in the cavity 1122, the pressure is increased and the speed starts to decrease. In addition, in order to prevent the generation of burrs due to surge pressure, the speed may be reduced intentionally. When the plunger tip 1111 reaches C position and the molten metal fills the cavity 1122, the injection pressure (head side pressure of the injection cylinder) rises, so when the measurement value of the pressure sensor becomes the setting switching pressure, the next pressure increase Switch to the process (see the third drawing from the top of FIG. 24).
In the pressure rising step, if the pressure is raised too quickly, burrs are generated, and if it is slow, shrinkage spots are generated, so the pressure is increased at an appropriate pressure rising speed. Then, when reaching the set holding pressure (P), the molten metal pressure is held and controlled for a certain period of time (holding step), and the molten metal is solidified, cooled and contracted to advance the plunger tip 1111 (see FIG. See the figure).

Since high-speed injection and high holding pressure are required in this way, the injection device of the conventional die casting machine has been driven by a hydraulic device. This hydraulic system requires many devices such as a hydraulic pump, a large capacity accumulator, a gas bottle, a switching valve, piping, an oil tank, etc., and the hydraulic circuit is complicated. As a result, there have been problems such as an increase in size of the device, oil leakage, and an increase in maintenance work. Furthermore, since the hydraulic fluid flows at high speed in the hydraulic circuit, a pressure loss occurs and an energy loss occurs.

In order to solve these problems, in recent years, a motorized system has been developed which drives a device by a combination of a servomotor and a ball screw.
In Patent Documents 1 and 2, high-speed operation is performed using an oil pressure accumulator at the time of high-speed injection in the injection filling process, and in the low-speed injection and pressure holding process (pressure increasing process) Discloses an injection mechanism of the type that drives the In the systems of these Patent Documents 1 and 2, a rotational transmission system composed of a timing belt, a pulley and the like directly transmits rotational force from the rotational shaft of the servomotor to the ball screw shaft.

Moreover, in patent document 3, the mechanism which drives an injection filling process and a pressure | voltage rise holding process by the combination of another servomotor and a ball screw is employ | adopted, respectively. Then, the mechanism for the pressure rising and holding step exerts a larger force than the mechanism for the injection and filling step, and the mechanism for the injection and filling step is loosened and retracted in the pressure rising and holding step. An injection mechanism is disclosed, in which a ratchet intervenes between two mechanisms to lock the mechanism for the injection filling process and also to apply a large holding force.

On the other hand, in these electric drive systems, the moment of inertia of the rotating body such as the rotating shaft and ball screw shaft of the electric motor and the coupling connecting the rotating shaft and the ball screw shaft becomes large. In addition, kinetic energy is increased by rotating the rotating body at high speed according to high-speed ejection. Then, the rotation does not stop immediately after the molten metal fully fills the mold cavity, and the plunger continues to advance. As shown in FIG. 25, when the plunger advances even after full filling of the molten metal, the molten metal in the mold cavity is excessively compressed and a momentary large pressure (surge pressure) is generated. When surge pressure occurs, the mold parting surface opens to cause burrs, and in severe cases, the mold is damaged.
Furthermore, since the plunger tip receives a large reaction force by the surge pressure, an impact-like decelerating force acts on the rotating body that has been rotating at a high speed so that the ball screw, thrust bearing, coupling, etc. are damaged. There is also a problem.

In order to solve these problems, in Patent Document 4, a friction clutch is interposed between the servomotor and the ball screw, and transmission is performed so that the moment of inertia and kinetic energy of the rotation shaft of the servomotor are not transmitted to the plunger. A motorized injection mechanism of the type that limits torque is disclosed.

Moreover, in patent document 5, while providing a pool at the flow end part of a mold cavity in injection filling using the injection mechanism of an electric drive system, while the molten metal tip is flowing in the inside of a cavity, injection speed is An electric injection control method is disclosed that prevents surge pressure by decelerating and switching to torque control.

Japanese Patent Application Publication No. 2006-315050 Japanese Patent Application Publication No. 2006-315071 JP 2008-87064 A JP 2007-296550 A JP, 2008-126294, A

However, although the mechanisms described in Patent Documents 1 and 2 are driven by the electric servomotor during the pressure holding process, the injection filling process still uses a large injection cylinder and an accumulator, so a large oil tank and piping are used. , Hydraulic valves are required, and problems with hydraulic drive systems such as oil leaks and facility upsizing have not been solved.

Further, in the method described in Patent Document 3, although the mechanism for injection filling is locked by the ratchet, the ratchet is locked by the hooking of the plurality of claws aligned in the moving direction, so the locking position becomes discontinuous. Therefore, since the amount of hot water supply is not particularly constant, the timing for switching from the injection filling process to the pressure holding process is delayed and varies, which adversely affects the quality of the cast product.

Then, an object of this invention is to provide the injection device of the die-cast machine which can simplify equipment and can improve the quality of cast products, and its control method.

In order to solve the above problems, an injection device of a die casting machine according to the present invention is an injection device of a die casting machine for injecting and filling a molten metal in a sleeve into a mold by advancing a plunger, An injection filling device for advancing the plunger at a low speed and a high speed by a motor, a pressure holding device for applying pressure to the molten metal through the plunger, and the plunger during a holding pressure applied to the molten metal And a movement suppressing mechanism that suppresses the relative movement of the pressure holding device with respect to the moving part.

In the injection device of a die casting machine according to the present invention, the movement suppressing mechanism moves the plunger and the pressure-rising holding device by the pressure received from the molten metal when the pressure received from the molten metal is higher than a set pressure. It is preferable that it is a lock mechanism which suppresses relative movement of the parts.
In this case, the injection filling device may be driven by a servomotor and a screw, or may be driven by a linear motor.
The pressure rising and holding device may be driven by a servomotor and a screw.
Furthermore, even if the lock mechanism suppresses the relative movement of the plunger and the moving part of the pressure holding device by suppressing the rotation of the screw nut by the frictional force by the pressure the plunger receives from the molten metal. good.
Furthermore, the set pressure may be set by the elastic force of a spring or may be set by the pressure of the hydraulic fluid.
The method of controlling the injection device of these die casting machines is that in the injection filling process performing low speed and high speed advancing, the injection filling device performs speed control, and the pressure rising and holding device performs position holding control, and the plunger is a molten metal. In the boosting and holding step after the pressure received from the switching pressure reaches the switching pressure, the injection filling device performs pressure control or position holding control, and the boosting holding device performs pressure control.

An injection device of another die casting machine according to the present invention is an injection device of a die casting machine in which the molten metal in the sleeve is injected and filled in the mold by advancing the plunger, and the servo motor and the servo motor And a surge pressure preventing device connected between the linear motion part of the motion converter and the plunger.
In this case, a spring may be incorporated in the surge pressure preventing device, and the elastic deformation of the spring may prevent the surge pressure.
Further, the surge pressure prevention device comprises a hydraulic cylinder, and a piston rod of the hydraulic cylinder is connected to a plunger, and a flow passage communicating the head chamber and the rod chamber in the hydraulic cylinder is the inside of the piston head and the piston rod The orifice may be formed in the middle of the flow path, and the head chamber may be provided with a compressed spring.
Further, the surge pressure preventing device is formed of a hydraulic cylinder, a piston rod of the hydraulic cylinder is connected to a plunger, and a flow passage communicating with the head chamber and the rod chamber in the hydraulic cylinder crosses halfway by an external flow passage. , And may be connected to an accumulator.
Furthermore, the surge pressure preventing device is composed of a double diameter rod hydraulic cylinder, and a piston rod on one side of the hydraulic cylinder is connected to a plunger, and a plunger side rod chamber and an anti plunger in the hydraulic cylinder. The flow passage leading to the side rod chamber is connected in circuit via a check valve and a relief valve connected in parallel, and when the piston head moves to the plunger side, the hydraulic oil in the plunger side rod chamber is reversed via the check valve. It can flow without resistance into the plunger side rod chamber, and when the piston head moves to the opposite side to the plunger, the hydraulic oil of the opposite plunger side rod chamber receives resistance through the relief valve, and the opposite plunger side It may flow into the rod chamber.
Further, the surge pressure preventing device comprises a hydraulic cylinder, a rod of the hydraulic cylinder is connected to a plunger, and a head chamber in the hydraulic cylinder is connected in circuit with a head chamber of a hydraulic pressure absorbing hydraulic cylinder. The piston rod of the pressure absorbing hydraulic cylinder may be movable back and forth by a servomotor and a ball screw.
Still further, the surge pressure preventing device comprises a hydraulic cylinder, a rod of the hydraulic cylinder is connected to a plunger, and a head chamber in the hydraulic cylinder is connected with a tank via a flow control valve capable of continuously adjusting the flow. It may be a circuit connection.

Furthermore, in the injection device of a die casting machine according to the present invention, the pressure rising and holding device includes a servo motor, a ball screw for converting a rotational movement of the servo motor into a linear movement, and an advancing force of a linear portion of the ball screw. And a brake mounted between the servomotor and the ball screw and capable of suppressing the rotational movement of the ball screw, and the injection filling device performs the linear movement of the rotational movement of the motor. And the movement suppressing mechanism is a brake mounted between the motor of the injection filling device and the ball screw of the injection filling device and capable of suppressing the rotational movement of the ball screw, and the pressure holding step The pressure of the molten metal is increased while compressing the compression spring by the rotation operation of the servomotor, and after the pressure increase, the brake is released. By suppressing the rotational motion of the work Shi ball screw, it is preferably capable of retaining the melt pressure by the compression force of the spring.
In this case, a speed reducer may be mounted between the brake of the pressure rising and holding device and the ball screw of the pressure rising and holding device.
The method of controlling the injection device of these die casting machines adjusts the pressure of the oil chamber of the surge pressure prevention cylinder after switching from the injection filling process to the pressure increase process, and controls the contact speed of the plunger member and the lock cylinder It is characterized by

Still further, in the injection device of a die casting machine according to the present invention, a plunger member integrally coupled with the plunger and a high speed moving member coupled with the plunger member via a surge pressure preventing cylinder are further provided. The movement restraining mechanism is mounted on the high-speed moving member via a bearing, and is screwed with a trapezoidal screw, and is in contact with the plunger member by pressure received by the plunger and is relative to the trapezoidal screw The injection filling device is connected to the high speed moving member via the cushion cylinder, and the pressing and holding device presses the trapezoidal screw so as to press the trapezoidal screw. A holding force is applied to the molten metal from the plunger through the lock nut and the plunger member. Preferred.
In this case, the injection filling device may include an injection filling servomotor and an injection filling ball screw, and a nut portion of the injection filling ball screw may be integral with a moving portion of the cushion cylinder.
Further, the pressure rising and holding device may include a pressure rising servomotor and a pressure rising ball screw.
In the pressure-rising holding device, a compression spring for transmitting an advancing force of a nut portion of the pressure-raising ball screw to the trapezoidal screw, a pressure-rising ball screw mounted between the pressure-raising servomotor and the pressure-raising ball screw. And a brake capable of suppressing the rotational movement, and in the pressure holding step, the pressure increase of the molten metal pressure is performed while compressing the compression spring by the rotation operation of the pressure raising servomotor, and after pressure rising, the brake is operated to raise the pressure. It may be possible to hold the pressure of the molten metal by the compression force of the compression spring by suppressing the rotational movement of the ball screw.
Furthermore, the hydraulic oil in the oil chamber of the cushion cylinder may be controlled not to rise above a predetermined pressure by a relief valve connected in circuit.
Further, the oil chamber of the surge pressure preventing cylinder is connected in circuit to a surge pressure absorbing hydraulic cylinder, and the piston rod of the surge pressure absorbing hydraulic cylinder is moved by a hydraulic ball screw and a hydraulic servomotor. The position and pressure of the moving part of the surge pressure preventing cylinder may be controllable.
Furthermore, the oil chamber of the surge pressure preventing cylinder may be connected in circuit to a flow rate adjusting valve, and the position and pressure of the moving part of the surge pressure preventing cylinder may be controlled by the flow rate adjusting valve.
The method of controlling the injection device of these die casting machines adjusts the pressure of the oil chamber of the surge pressure prevention cylinder after switching from the injection filling process to the pressure increase process, and controls the contact speed of the plunger member and the lock cylinder It is characterized by

As described above, according to the present invention, it is possible to provide an injection device of a die casting machine capable of simplifying equipment and improving the quality of cast products and a control method thereof.

It is the schematic which shows the structure of the 1st Example of the injection device of the die-cast machine which concerns on 1st Embodiment. It is the schematic which shows the structure of the 2nd Example of the injection device of the die-cast machine which concerns on 1st Embodiment. It is the schematic which shows the structure of the 3rd Example of the injection device of the die-cast machine which concerns on 1st Embodiment. It is the schematic which shows the structure of the 4th Example of the injection device of the die-cast machine which concerns on 1st Embodiment. It is the schematic which shows the structure of the 5th Example of the injection device of the die-cast machine which concerns on 1st Embodiment. It is a graph which shows the control method in each process in the injection device of the die-cast machine which concerns on 1st Embodiment. It is the schematic which shows the structure and surge pressure prevention apparatus of 1st Example of the injection device of the die-cast machine which concerns on 2nd Embodiment. It is the schematic which shows the structure and surge pressure prevention apparatus of 2nd Example of the injection device of the die-cast machine which concerns on 2nd Embodiment. It is the schematic which shows the structure and surge pressure prevention apparatus of the 3rd Example of the injection device of the die-cast machine which concerns on 2nd Embodiment. It is the schematic which shows the structure and surge pressure prevention apparatus of the 4th Example of the injection device of the die-cast machine which concerns on 2nd Embodiment. It is the schematic which shows the structure and surge pressure prevention apparatus of 5th Example of the injection device of the die-cast machine which concerns on 2nd Embodiment. It is the schematic which shows the structure and surge pressure prevention apparatus of the 6th Example of the injection device of the die-cast machine which concerns on 2nd Embodiment. It is a time-axis graph which shows the injection speed and pressure in the injection filling process and the pressure | voltage rise holding process, and motor speed and torque in the injection device of the die-cast machine which concerns on 2nd Embodiment. It is the schematic which shows the structure of the injection device of the die-cast machine which concerns on 3rd Embodiment. It is a graph which shows the injection speed in each process, the pressure, the control method, etc. in the injection device of the die-cast machine which concerns on 3rd Embodiment. It is the schematic which shows the structure of the injection device of the die-cast machine which concerns on 4th Embodiment. It is the figure which looked at the injection device and die periphery of the die-cast machine which concerns on 4th Embodiment from the side, and the injection filling apparatus (ball screw for injection filling etc.) is abbreviate | omitted and shown. The injection device seen from arrow A in FIG. 17 is shown. FIG. 6 shows an embodiment of a hydraulic circuit connected to the oil chamber of the cushion cylinder. It is a figure which shows the Example of the hydraulic circuit connected with the oil chamber of a surge pressure prevention cylinder (ring-like cylinder). It is a figure which shows the other Example of the hydraulic circuit connected with the oil chamber of a surge pressure prevention cylinder (ring-like cylinder). It is a graph showing the speed, the pressure, and the state of each device during the injection filling process and the pressure rising and holding process. It is a figure which shows the injection apparatus of the conventional hydraulic drive system, and a die periphery. It is a figure and graph which show the relationship of the position of the plunger in general die casting, the state of a molten metal, injection speed, and molten metal pressure. It is a time-axis graph which shows the injection speed and pressure of the injection | pouring filling process and the pressure | voltage rise holding process in the conventional injection device, and represents the state which surge pressure generate | occur | produces.

Next, an injection device of a die casting machine according to a first embodiment of the present invention will be described based on FIGS. 1 to 6. Hereinafter, first to fifth examples of the injection device of the die casting machine according to the first embodiment will be described in detail.

First Embodiment
First, a first example of an injection device of a die casting machine according to the first embodiment will be described with reference to FIG. FIG. 1 is a schematic view showing a structure of a first example of an injection device of a die casting machine according to a first embodiment.
The base (main) frame 11 is connected to a fixed platen (not shown) and supported by the ground. The plunger 10 consisting of the plunger tip 10a and the plunger rod 10b is fitted in a sleeve (not shown), and by advancing operation, the molten metal in the sleeve can be injected and filled in the mold cavity. The plunger 10 is connected to the slide member 15, and the injection filling ball screw nut 17 is incorporated in the slide member 15. The injection filling ball screw shaft 16 integral with the injection filling ball screw nut 17 is supported by the bearing holding member 18 via the injection filling bearing 19 and the pressing nut 20, and is rotated by the injection filling servomotor 12. .

Since the axis of the injection filling servomotor 12 and the injection filling ball screw shaft 16 are connected by the spline shaft 21, relative movement in the axial direction is possible, but movement in the rotational direction is restricted. It has become. The bearing holding member 18 is attached to the main member 14 in a slidable and rotationally restrained state by the bearing holding member linear guide 24b. Moreover, it is attached also through the spring 22 and the holding member 23 of a compression state (compression force f). A friction disc 25 is fixed to the end face of the injection filling ball screw shaft 16, and a small (0.5 to 1 mm) gap is formed between the main member 14 and the spring by the compression state. There is. The injection filling servomotor 12 is attached to the main member 14, and when it rotates, it rotates the injection filling ball screw shaft 16 to move the slide member 15 and the plunger 10 back and forth.

The main member 14 is slidably mounted on a main member linear guide 24 c provided on the main frame 11. Further, a pressure holding device comprising a pressure holding ball screw nut 28, a motor support member 26 fixed to the main frame 11, a pressure holding ball screw shaft 27, a coupling 29 and a pressure holding bearing 30 in the main member 14. 32 is attached. Further, the pressure holding servo motor 13 and the pressure holding ball screw shaft 27 are connected by a coupling 29. When the step-up holding servomotor 13 is driven to rotate, the step-up holding ball screw nut 28 and the main member 14, which are moving parts of the step-up holding device 32, move forward and backward, and the pressure holding pressure is transferred to the molten metal via the plunger. It can be added.
In FIG. 1, although the pressure rising and holding device 32 is described as a mechanism using a servomotor and a ball screw, the same operation is performed even if the main body of the hydraulic cylinder is fixed to the main frame 11 and the rod is connected to the main member It can produce an effect.

A control method of the injection filling process and the pressure rising and holding process for the injection device of the die casting machine configured as described above will be described with reference to FIG. FIG. 6 is a graph showing a control method in each process in the injection device of the die casting machine according to the first embodiment.
As described above, in the injection and filling process, the forward movement of the plunger 10 is first performed at low speed, and then the high speed injection is performed when the surface of the molten metal reaches near the gate of the mold. During the injection and filling process, the injection and filling servomotor 12 performs speed control in accordance with the set speed, and the pressure rising and holding servomotor 13 performs position holding control. The compression force f of the spring 22 is designed to be sufficiently larger than the injection pressure received by the plunger 10 during the injection and filling process (such as selection of the spring constant). The injection filling ball screw shaft 16 can rotate smoothly without contact between the main body 25 and the main member 25.

When the inside of the mold cavity is close to full filling with molten metal, the injection speed is reduced. Then, since the injection pressure (metal pressure received by the plunger 10) rises rapidly in the full-filling state, when the set switching pressure is reached, the pressure is switched to the pressure holding process. In the pressure rising and holding process, the pressure rising and holding servomotor 13 is subjected to torque control (pressure control) so as to correspond to the set pressure rising speed and holding pressure. Also, the injection filling servomotor 12 is subjected to the same torque control or position holding control. The injection pressure may be measured by a pressure sensor for molten metal provided in a sleeve or a mold, or a load cell provided in the plunger 10, or the torque of the injection filling servomotor 12 or the pressure holding servomotor 13 It may be converted from the measured value.

After switching to the pressure increase holding process, the injection pressure (molten metal pressure) further increases, and when the compression force f of the spring 22 is exceeded, the gap disappears and the friction disc 25 and the main member 14 start contact. Further, when the injection pressure increases and the pressing force between the friction disc 25 and the main member 14 increases, the friction force against the rotation increases, and the rotation of the injection filling ball screw shaft 16 is suppressed and locked.
Thus, the lock mechanism (movement suppressing mechanism) is configured from the friction disc 25, the contact portion of the main member 14, the spring 22, the pressing member 23 and the like.

Here, let F be the injection pressure (set pressure) when the rotation of the injection filling ball screw shaft 16 is locked. The radius of the friction disc 25 is r, the friction coefficient is μ, and the lead of the injection filling ball screw shaft 16 is L. From the relationship between the friction energy when rotating one turn with the pressing force (Ff) and the propulsion energy when advancing L with the force of F, equation (1) holds, and the injection pressure is greater than F satisfying equation (1) The rotation is locked as it gets larger.
2π · μ (F−f) · r = F · L (1)
When equation (1) is modified, equation (2) is obtained.
F = {(2π · μ · r) / (2π · μ · r−L)} · f (2)
Therefore, the setting of F (set pressure) can be changed by appropriately designing the radius r of the friction disk, the compression force f of the spring, and the like.

The injection filling ball screw shaft 16 is locked when the injection pressure increases to F or more satisfying the equation (2), so the injection filling ball screw nut 17 and the injection filling ball screw shaft even if the pressure-rising holding force becomes large. 16 does not loosen (the injection filling servomotor 12 and the injection filling ball screw are designed to have a high speed, so they can not exert a force large enough to resist the pressure holding force).
Then, it is possible to load the molten metal (metal) through the plunger 10 with the large holding power exerted by the pressure holding device 32 and the pressure holding servo motor 13.

The second to fifth examples of the injection device of the die casting machine according to the first embodiment will be described below, but the operation and control method of the basic device are the same as those of the first example.

Second Embodiment
A second example of the injection device of the die casting machine according to the first embodiment will be described with reference to FIG. FIG. 2 is a schematic view showing the structure of a second example of the injection device of the die casting machine according to the first embodiment.
A main member 48 is connected to the base frame 11 via a main member linear guide 46b, and a pressure holding device 32 and a pressure holding servomotor 13 similar to those of the first embodiment are also attached. The plunger 10 is integrally attached to the plunger holding member 35 and the key holding member 36. The key holding member 36 is incorporated in the bearing holding member 37 via the key 38 and the spring 39 in a compressed state (compression force f), and can slide in the longitudinal direction of the plunger 10 and its rotation is restricted. There is. The key 38 may be a spline. Further, a nut 41 is incorporated in the bearing holding member 37 via the bearing 50 and the bearing retainer 42. A friction disc 49 is attached to an end face of the nut 41 on the plunger 10 side, and a gap is formed between the friction disc 49 and the key holding member 36 by the compression force of the spring 39. The nut 41 is screwed to the screw shaft 40, and one end of the screw shaft 40 is fixed to the screw shaft support member 43 by the key 44 and the pressing nut 45. Further, the screw shaft support member 43 is integrated with the main member 48.

The fixed portion of the linear motor 47 is attached to the main member 48, and the movable portion is connected to the bearing holding member 37. Further, the fixed portion of the linear motor 47 may be attached to the main frame 11. Further, the bearing holding member 37 is supported on a bearing holding member linear guide 46a provided on the main frame 11, and although the longitudinal movement of the plunger 10 is possible, the rotation is restricted.

When the linear motor 47 is advanced in such a state, the gap is secured, so that while the nut 41 rotates, the plunger 10, the plunger holding member 35, and the bearing holding member 37 are advanced, and injection filling is performed. Be When the injection pressure becomes high, the spring 39 is further compressed as in the first embodiment, and the friction disc 49 of the nut 41 and the key holding member 36 start contact, and when the height reaches F further, the nut 41 is locked. Ru. Then, since the plunger 10, the bearing holding member 37, the nut 41, the screw shaft 40, the screw shaft support member 43, the main member 48, etc. are integrated, the large pressure holding device 32 and the pressure holding servomotor 13 drive The holding power can be applied to the molten metal.

Third Embodiment
Next, a third example of the injection device of the die casting machine according to the first embodiment will be described with reference to FIG. FIG. 3 is a schematic view showing the structure of a third example of the injection device of the die casting machine according to the first embodiment. The third embodiment is a modification of the second embodiment, so only the differences will be described.
In the second embodiment, the forward and backward movement of the bearing holding member 37 is driven by a linear motor, but in the third embodiment, it is performed by a combination of the ball screw type high speed injection device 52 and the injection filling servomotor 12. In the second embodiment, a spring in a compressed state is incorporated between the key holding member 36 and the bearing holding member 37, but in the third embodiment, the ring-shaped cylinder 51 is incorporated. From the oil chamber of the ring-shaped cylinder 51, hydraulic fluid is communicated with the hydraulic device by piping. The hydraulic system comprises a hydraulic pump 53, an electric motor 54, an oil tank 56, and a proportional electromagnetic pressure control valve 55, and applies pressure to the hydraulic oil of the oil chamber of the ring-like cylinder 51 to compress it according to the second embodiment. It can exhibit the same action as the state spring. The oil pressure in this case is the same as the compression force f of the spring in the second embodiment.

Therefore, in the injection filling process, the plunger 10 is advanced at high speed by the ball screw type high speed injection device 52 and the injection filling servomotor 12, and in the pressure rising and holding process, the pressure rising and holding device 32 and the pressure rising and holding servo motor 13 The molten metal can be loaded with a large holding power. In this case, the pressure may be reduced by adjusting the proportional electromagnetic pressure control valve 55 during the pressure holding process.
Replacing the spring of the second embodiment with the ring-shaped cylinder 51 and the hydraulic device of the third embodiment can be applied to the first embodiment and the fourth and fifth embodiments described later.

Fourth Embodiment
Next, a fourth example of the injection device of the die casting machine according to the first embodiment will be described with reference to FIG. FIG. 4 is a schematic view showing the structure of a fourth example of the injection device of the die casting machine according to the first embodiment.
The main member 64 is attached to the base frame 11 via the linear guide 46b for the main member, and the pressure holding device 32 and the pressure holding servo motor 13 are also attached. The plunger 10 is connected to a plunger holding member 61. The plunger holding member 61 is incorporated in the slide member 60 through the key 61a and the spring 62 in a compressed state (compression force f) while being allowed to slide back and forth but being restrained from rotating. . In the slide member 60, a shaft 66 is incorporated via a shaft bearing 65 and a plurality of spacers 66a. A friction disc 63 is attached to an end face of the shaft 66 on the plunger 10 side, and a bevel gear 67 a is connected to the opposite side. A pair of bevel gears 67b is engaged with the bevel gear 67a, and a pinion shaft 68 connected to the bevel gear 67b is rotatably attached to the slide member 60 via a pinion bearing 68a and a plurality of spacers. A pinion 69 is connected to the opposite side of the pinion shaft 68, and the pinion 69 meshes with the rack 70. The rack 70 is fixed to the main member 64. The fixed portion of the linear motor 47 is attached to the main member 64, and the movable portion is attached to the slide member 60. Furthermore, here, a gap is secured between the friction disc 63 and the plunger holding member 61 by the compression force f of the spring 62.

In the injection and filling process, by driving the linear motor 47, the plunger 69 advances while the pinion 69, the pinion shaft 68, the bevel gears 67a and 67b, the shaft 66 and the friction disc 63 rotate. In the pressure rising and holding step, the friction disc 63 comes into contact with the plunger holding member 61 and the rotation is restrained, whereby the rack 70, the pinion 69, the slide member 60, etc. are integrated (locked) and pressure rising and holding device 32 and pressure rising and holding The large holding power exerted by the servomotor 13 can be loaded on the molten metal through the plunger 10.

Fifth Embodiment
Next, a fifth example of the injection device of the die casting machine according to the first embodiment will be described with reference to FIG. FIG. 5 is a schematic view showing the structure of a fifth example of the injection device of the die casting machine according to the first embodiment.
The main body 80 can slide on the main frame (not shown) in the longitudinal direction of the plunger 10, and the pressure holding device 32 and the pressure holding servo motor 13 are attached. An outer wedge 81 and an inner wedge 82 are incorporated into the body 80. Rollers 84 are incorporated between the outer wedge 81 and the inner wedge 82 so that they can slide without friction. Also, the inner wedge 82 is connected to the plunger 10. Furthermore, the inner wedge 82 is connected to the moving member 85 via the spring 83 in a compressed state (compression force f). The moving member 85 is coupled to the movable portion of the linear motor 47, and the moving member 85 and the outer wedge 81 are slidably coupled in the vertical direction of the drawing. When the metal pressure received by the plunger 10 is small, a gap is formed between the main body 80 and the outer wedge 81.

When the linear motor 47 is driven in such a state, the plunger 10, the outer wedge 81, the inner wedge 82, the spring 83, the roller 84 and the moving member 85 are advanced, and the injection filling process is operated. And if injection pressure becomes high and switches to a pressurization holding process, spring 85 will be compressed and two outside wedges 81 will be spread. Then, the gap disappears and the main body 80 contacts the outer wedge 81. By appropriately setting the angle between the outer wedge 81 and the inner wedge 82, the frictional force between the main body 80 and the outer wedge 81 becomes larger than the injection pressure that the plunger 10 receives, and the main body 80 and the plunger 10 Etc. unify (lock). In this state, when the pressure holding motor 13 is driven to cause the pressure holding device 32 to act, a large holding force can be loaded on the molten metal.

As described above, according to the injection device of the die casting machine according to the first embodiment, the following advantageous effects can be achieved.
(1) Since the locking of the injection filling device is achieved by the increase of the injection pressure, it is possible to shift from the injection filling step to the pressure holding step continuously and stably.
(2) Since the drive source for high-speed injection operation is a servomotor, a large accumulator, gas bottle, hydraulic piping, etc. are not required, and the apparatus is simplified and maintenance is improved. In addition, energy loss due to pressure loss that occurs when hydraulic oil flows at high speed is eliminated, and energy saving operation can be achieved.
(3) The feedback control by the servomotor is possible, and the freedom of operation condition setting and the stability of operation control are increased.

The injection apparatus of the die casting machine according to the first embodiment can be put to practical use in a production plant that casts an aluminum product by the die casting machine, and can contribute to simplification of equipment, improvement of productivity and maintainability, and energy saving operation.

Next, an injection device of a die casting machine according to a second embodiment of the present invention will be described based on FIG. 7 to FIG. Hereinafter, first to sixth examples of the injection device of the die casting machine according to the second embodiment will be described in detail.

First Embodiment
First, a first example of an injection device of a die casting machine according to the second embodiment will be described with reference to FIG. FIG. 7 is a schematic view showing a structure of a first example of an injection device of a die casting machine according to a second embodiment and a surge pressure preventing device.
The servomotor 115 is connected to the ball screw shaft 118 via a motor coupling 116. The ball screw shaft 118 is supported in a rotatable but axially restrained state by a bearing incorporated in the bearing box 117. A ball screw nut 119 screwed with the ball screw shaft 118 is fixed to the moving member 114. Further, the surge pressure preventing device 120 is fixed to the moving member 114, and the movable portion of the surge pressure preventing device 120 is coupled to the plunger rod 112 by the plunger coupling 113. The plunger tip 111 is fixed to the tip of the plunger rod 112, and the plunger 110 is integrally formed. The bearing box 117 is fixed relative to a stationary platen that holds the mold so that it can transfer the blast power to the melt in the mold cavity. Further, the moving member 114 is slidably supported by a linear slide (not shown). Here, a ball screw or the like performs the function of a motion conversion device that converts rotational motion into linear motion.

The surge pressure prevention device 120 is in the form of a hydraulic cylinder, and comprises a cylinder body 121 of the main body portion, a piston rod 121 of the movable portion, and a piston head 123. The head chamber of the hydraulic cylinder incorporates a shock absorbing spring 124 in a compressed state, which provides resistance to the force with which the piston head 123 is pushed rearward (right side in the drawing). Further, the rod chamber and the head chamber are in communication with the atmosphere via the air breather 125, so that air can enter and exit without entering dust inside. It is also possible to incorporate a load cell in the coupling 113 connecting the plunger 110 and the piston rod 122 so that the injection pressure can be measured. Also, the cylinder body 121 may be integral with the moving member 114.

Here, assuming that the switching pressure (molten metal pressure) of the conditions for switching from the injection filling step to the pressurization holding step is Pc and the diameter of the plunger tip is Dp, the switching force at that time is Fc = (π / 4) · Dp 2 It becomes. Therefore, the shock absorbing spring 124 is loaded with a compressive force (Fs) equal to or slightly larger than Fc (for example, 1.05 to 1.1 times) and incorporated. Therefore, the shock absorbing spring 124 is not contracted during injection and filling.

An injection filling process and a pressure holding process performed using such an injection device will be described with reference to FIG. The upper figure is a time-axis graph of the injection speed of the plunger 110 and the injection pressure (melt pressure, metal pressure) received by the plunger tip 111, and the lower figure is the rotational speed (motor speed) and rotational torque of the servomotor. It is a time-axis graph which shows (motor torque).
First, the servomotor 115 starts to rotate to a low injection speed. At the time of acceleration at this time, a large motor torque is required in order to rotate and accelerate a rotating body having a large inertia moment such as the motor shaft of the servomotor 115, the coupling 116, and the ball screw shaft 118. When the predetermined stroke is advanced, the injection speed becomes high next, but since it is necessary to accelerate to high speed in a short time, the motor torque at that time also becomes large. During low speed and high speed injection, the motor rotational speed and the injection speed are in a proportional relationship.

As the plunger 110 advances, the injection pressure (melt pressure) starts to rise as the mold cavity is almost filled with the melt. Then, when control is performed to increase the switching pressure (Pc), the servomotor 115 is switched to torque control (boosting step), and the injection pressure is further controlled to increase. Immediately after this, since the shock absorbing spring 124 starts to exert a compressive force exceeding Fs, the shock absorbing spring 124 is contracted. By this, even if the advancing speed of the plunger becomes almost zero, the rotating body such as the ball screw shaft 118 can keep rotating by the amount by which the shock absorbing spring 124 is contracted. Therefore, since the decelerating time and the decelerating rotation angle of the rotating body can be secured, it can be stopped gradually. As shown in FIG. 13, during the deceleration time, the rotational speed of the servomotor and the injection speed (the speed of the plunger) are not in proportion.
The kinetic energy of the rotating body is absorbed by the shock absorbing spring 124 by these things. Accordingly, since the molten metal in the mold cavity is not excessively compressed, the generation of surge pressure can be prevented, the generation of burrs can be avoided, and the impact force can also be prevented.

In the boosting step, the motor torque is controlled to rise along the set boosting speed. When the set holding pressure is reached, constant torque holding control is performed. Then, when the set holding time has elapsed, the holding force is lowered to 0, and the holding process is completed. Thereafter, the process proceeds to the next mold opening process. If the required holding pressure can not be increased only by the torque of the servomotor 115, a holding pressure assisting device may be attached to the moving member 114 to compensate.

Hereinafter, although the second to sixth examples of the injection device of the die casting machine according to the second embodiment will be described, since the basic portion, action and control method of the device have many parts in common with the first example. , Only the differences will be described.

Second Embodiment
A second example of the injection device of the die casting machine according to the second embodiment will be described with reference to FIG. FIG. 8 is a schematic view showing a structure of a second example of the injection device of the die casting machine according to the second embodiment and a surge pressure preventing device.
The hydraulic cylinder of the surge pressure prevention device 120 is filled with hydraulic oil, and the rod chamber 137 is connected to the tank 135 by piping. A projection 131 is attached to the head chamber side of the piston head 123, and a disc spring 132 is attached to the outside thereof. The disc spring 132 has a compression force of Fs and is incorporated therein, and the piston head 123 is pressed to the rod chamber 137 side of the cylinder body 121. A packing is incorporated in the sliding portion to prevent the hydraulic oil from leaking. A flow path 133 is provided inside the protrusion 131, the piston head 123, and the piston rod 122, and the head chamber 136 and the rod chamber 137 are in communication. In the middle of the flow path 133, an orifice 134 of a small diameter portion is provided to restrict the flow of hydraulic oil.

When the molten metal pressure pushes the plunger 110 with a force of Fs or more, the disc spring 132 is further compressed, and the hydraulic oil in the head 136 flows through the flow path 133 to the head chamber 137. At this time, when passing through the orifice 134 in the middle of the flow path 133, the working oil is squeezed, a pressure is generated in the head chamber 136 side, and the reaction force becomes larger together with the force of the disc spring 132, and shock absorption is more It is done effectively. As the rod chamber 137 expands in volume, hydraulic oil is supplied from the tank 135. In addition, the stroke of the cylinder needs to be designed to be longer than the length capable of shock absorption (kinetic energy absorption).

Third Embodiment
Next, a third example of the injection device of the die casting machine according to the second embodiment will be described with reference to FIG. FIG. 9 is a schematic view showing the structure and surge pressure prevention device of the third example of the injection device of the die casting machine according to the second embodiment.
The hydraulic cylinder of the surge pressure prevention device 120 is filled with hydraulic oil, and the head chamber 144 is connected in circuit to an external accumulator side throttle valve 142 and an accumulator 141 via an external flow path. The rod chamber 145 is also connected to the flow passage on the head chamber 144 side via the rod-side throttle valve 143 by the external flow passage. The pressure of the accumulator 141 is a pressure at which the hydraulic oil pushes the piston head at Fs.
Assuming that the inner diameter of the cylinder is Ds, the rod diameter is Dr, and the accumulator pressure is Psa, Psa can be calculated from Fs = (π / 4) · Dr2 · Psa.

When the plunger is pushed with a force of Fs or more, the piston moves rearward (right side in the figure), and the hydraulic fluid in the head chamber 144 flows out to the rod chamber 145 and the accumulator 141. At this time, since the flow of the hydraulic oil is throttled by the accumulator side throttle valve 142 and the rod side throttle valve 143, the pressure in the cylinder becomes equal to or higher than Psa, and the reaction force against the piston moving backward becomes large. This makes shock absorption more effective, since shock absorption takes place while the piston is moving backwards. Also in this case, it is necessary to design the stroke of the cylinder appropriately so that shock absorption (absorption of kinetic energy) can be performed before the piston head reaches the cylinder end.

Fourth Embodiment
Next, a fourth example of the injection device of the die casting machine according to the second embodiment will be described with reference to FIG. FIG. 10 is a schematic view showing the structure of a fourth example of the injection device of the die casting machine according to the second embodiment and the surge pressure preventing device.
The surge pressure prevention device 120 is a dual rod type hydraulic cylinder with equal rod diameter, and the anti-plunger side rod chamber 153 and the plunger side rod chamber 154 are filled with hydraulic oil. The anti-plunger side rod chamber 153 and the plunger side rod chamber 154 are externally connected in circuit via the check valve 152, and the hydraulic oil flows from the plunger side rod chamber 154 to the anti plunger side rod chamber 153. However, the circuit does not flow in the opposite direction. In addition, a relief valve 151 is connected in parallel with the check valve 152, and hydraulic fluid flows from the anti-plunger side rod chamber 153 to the plunger side rod chamber 154 at a pressure higher than the set pressure. It is a circuit that does not flow.
Therefore, when the plunger moves rearward (right side in the drawing), resistance of the set pressure of the relief valve 151 works, while when moving forward (left side in the drawing), movement by resistance of the check valve 152 works without resistance. be able to. Further, assuming that the set pressure of the relief valve is Psb, Psb can be converted from Fs = (π / 4) · (Ds2-Dr2) · Psb.

When the plunger is pushed with a force of Fs or more, the piston moves rearward (right side in the figure), and the hydraulic oil of the anti-plunger side rod chamber 153 flows out to the plunger side rod chamber 154. At this time, since a pressure of Psb is generated in the anti-plunger side rod chamber 153 and a reaction force works, prevention of surge pressure and shock relaxation are effectively performed.

Fifth Embodiment
Next, a fifth example of the injection device of the die casting machine according to the second embodiment will be described with reference to FIG. FIG. 11 is a schematic view showing the structure and surge pressure prevention device of the fifth example of the injection device of the die casting machine according to the second embodiment.
The head chamber 162 of the hydraulic cylinder, which is the surge pressure preventing device 120, is filled with the hydraulic fluid, and the rod chamber 163 contains air, so that air can enter and exit through the air breather 161. The head chamber 162 is connected in circuit to the head chamber of the surge pressure absorbing hydraulic cylinder 167, the spring accumulator 164, and the switching valve 165 by piping. The piston rod of the surge pressure absorbing hydraulic cylinder 167 is integrally connected with the nut holder 168 and the ball screw nut 169, and the ball screw shaft 170 screwed with the ball screw nut 169 is a motor shaft of the servomotor 172 by the coupling 171. It is linked with The switching valve 165 is in circuit connection with the tank 166 and is normally closed. However, when the hydraulic oil in the head chamber 162 or the like decreases due to a leak or the like, the solenoid is energized and the valve is opened to operate the tank 166. Oil can be supplied to the head chamber 162 and the like.

At the start of the injection process, the servomotor 172 is torque-controlled, and the hydraulic pressure generated in the head chamber and the head chamber 162 of the surge pressure absorbing hydraulic cylinder 167 is adjusted to Psc by the action of the ball screw.
Psc is a pressure that satisfies Fs = (π / 4) · Ds2 · Psc, where Ds is the inner diameter of the cylinder and Psc is the pressure. Also, the spring-type accumulator 164 is set to have a spring force so as to balance the force that the internal piston receives with the pressure Psc.
When the injection pressure becomes large and the injection output becomes Fs, the piston head 123 starts to move rearward (right side in the figure). At this time, the pressure in the head chamber 162 is maintained at Psc by controlling the torque while the servomotor 172 rotates in the backward direction. If the piston head 123 starts moving quickly and the piston rod etc. of the surge pressure absorbing hydraulic cylinder 167 loses inertia due to the inertia of the piston rod etc., the piston of the spring accumulator 164 retreats (the lower side of the figure) It is maintained almost at Psc. During the movement of the piston head 123 to the cylinder end, the rotation speed of the rotating body such as the ball screw shaft 118 (see FIG. 7) is gradually reduced to almost zero rotational speed, so that no surge pressure is generated in the molten metal.

Sixth Embodiment
Next, a sixth example of the injection device of the die casting machine according to the second embodiment will be described with reference to FIG. FIG. 12 is a schematic view showing the structure of a sixth example of the injection device of the die casting machine according to the second embodiment and the surge pressure preventing device.
As in the fifth embodiment, the head chamber 182 of the hydraulic cylinder which is the surge pressure preventing device 120 is filled with the hydraulic fluid, and the rod chamber 183 is filled with air and the air breather 181 is used to It is possible to go in and out. In the head chamber 182, the piping path branches along the way, and is in circuit connection with the spring accumulator 184, the check valve 185, the flow control valve 191, and the pressure sensor 190. The flow rate adjustment valve 191 is structured such that the opening degree can be freely changed from the closed state to the fully open state by the rotation control of the servomotor 192, and the flow rate of hydraulic fluid flowing from the head chamber 182 to the tank 193 can be adjusted. . The check valve 185 is in circuit connection with the pump 186, the tank 188, the electric motor 187, and the relief valve 189, and can supply the hydraulic fluid to the head chamber 182 at an appropriate pressure. Also, the spring-type accumulator 184 is set to have a spring force so as to be balanced with the force that the internal piston receives due to the pressure Psc.

At the start of injection, the pressure of the hydraulic oil in the head chamber 182 is maintained at Psc by the action of the pump 186, the electric motor 187 and the relief valve 189. Further, the action of the check valve 185 prevents the hydraulic oil from flowing in the direction from the head chamber 182 to the pump 186.
When an injection force exceeding Fc acts on the plunger, the pressure of the hydraulic fluid in the head chamber 182 rises, so that pressure is detected by the pressure sensor 190, and the opening degree of the flow rate adjustment valve 191 is controlled so that the pressure does not exceed Psc. Adjust and release the hydraulic oil to the tank 193. When there is a response delay of the flow control valve 191, the piston of the spring-type accumulator 184 moves and the pressure is maintained at approximately Psc.
Due to such an action, no surge pressure is generated in the molten metal as in the fifth embodiment.

In the mechanism described in Patent Document 4 of the prior art, the moment of inertia of the ball screw shaft mounted on the plunger side of the friction clutch is transmitted to the molten metal, so that the cause of the surge pressure still remains.
Further, according to the conventional method of Patent Document 5, in the injection apparatus for high speed and high pressure which requires a large capacity servomotor, the inertia moment of the rotating body such as the shaft of the servomotor becomes large. There is a problem that it is necessary to increase the size of the bath and waste occurs such as using a large amount of molten metal in one casting. Furthermore, if the speed is reduced during filling, the tip of the hot water will fly in the cavity and air will be caught, causing a void defect in the product, resulting in a defect.

On the other hand, according to the injection device of the die casting machine concerning a 2nd embodiment, the following advantageous effects can be produced.
(1) Even in the case of an electric injection device with a large inertia, the surge pressure at the time of full filling in which the inside of the mold cavity is filled with the molten metal can be prevented, so generation of burrs and damage to the mold associated therewith can be avoided is there.
(2) It is possible to perform high-speed injection filling up to the full filling or just before that, and the quality of the cast product is improved by avoiding the jump of the hot water tip and shortening the filling time.
(3) The impact force generated on the servomotor, the ball screw, the coupling, and the bearing as the reaction force of the surge pressure is alleviated, and mechanical damage and failure can be avoided.

The injection device of the die casting machine according to the second embodiment can be put to practical use in a production plant that casts an aluminum product by the die casting machine, and can contribute to quality improvement of cast products and stable operation of a casting facility.

Next, an injection device of a die casting machine according to a third embodiment of the present invention will be described based on FIG. 14 and FIG. FIG. 14 is a schematic view showing a structure of an injection device of a die casting machine according to a third embodiment.

A plunger 210 consisting of a plunger tip 210a and a plunger rod 210b is in a slidable state in a sleeve (not shown), and by advancing it can inject and fill the molten metal in the sleeve into the mold cavity. At that time, the tip surface of the plunger tip 210a receives metal pressure (injection pressure) from the molten metal. The plunger rod 210b is connected to the slidable injection slide member 215 by a linear guide. An injection filling ball screw nut 217 is attached to the injection slide member 215, and moves forward and backward by rotational movement of the injection filling ball screw shaft 216 screwed with the injection filling ball screw nut 217. The injection filling ball screw shaft 216 is attached to the bearing holding member 218 in an axially constrained but rotatable state by the injection filling bearing 219 and the pressing nut 220. The injection filling ball screw shaft 216 is connected to the rotation portion of the injection filling brake 221 (movement suppressing mechanism), and is further connected to the rotation axis of the injection filling servomotor 212 via the coupling 222. Therefore, when the injection filling servomotor 212 is rotated, the injection slide member 215 and the plunger 210 can be moved forward and backward. The injection brake 221 is an electromagnetic type, and when an electric current is applied, a braking force is exerted, and the rotation of the injection filling ball screw shaft 216 can be suppressed. In order to realize high-speed injection, it is preferable that the lead of the injection filling ball screw be large.

A main member 214 is slidably attached to the base frame 211 via a linear guide 223. The aforementioned injection slide member 215 is slidably attached to the main member 214 via a linear guide, and a bearing holding member 218 is integrally fixed. On the bearing holding member 218, an injection filling servomotor 212, an injection filling brake 221, and an injection filling bearing 219 are mounted.
Although not shown, since the base frame 211 is integrally connected to a fixed plate for holding the mold, the molten metal in the mold cavity is moved forward by moving the plunger 210 (left direction in the figure). Metal pressure can be loaded.
Further, the portion excluding the upper plunger 210 of FIG. 14 is an injection filling device.

The lower part of FIG. 14 is a pressure holding device. The pressure holding member 238 is coupled to the base frame 211, and a pressure boosting servomotor 230, a holding brake 232, a reduction gear 233, and a pressure holding bearing 235 are attached. The rotational shaft of the pressure-raising servomotor 230 is coupled to the rotational portion of the holding brake 232 via a coupling 231, and is further coupled to the rotational shaft of the reduction gear 233 and the ball screw shaft 236. The ball screw shaft 236 is axially restrained and rotatably supported by the pressure holding bearing 235 and the bearing holding nut 234. A nut holder 239 is attached to the ball screw nut 237 screwed with the ball screw shaft 236, and the nut holder 239 can axially move in the pressure holding slide member 241 via the key 242. Is confined in the direction of rotation. Further, a spring 240 is mounted between the nut holder 239 and the pressure holding slide member 241 in a compressed state. The spring 240 may be a coil spring or a disc spring. The pressure holding slide member 241 is fixed to the lower side of the main member 214 and is slidably attached to the base frame 11 via a linear guide.
In this case, the straight part of the ball screw for pressure increase is the ball screw nut 237. In addition, since the ball screw for pressure increase needs to exert a large force (forward force), it is better that the lead is not so large.

Next, an injection filling process, a pressure holding process, and a control method thereof performed by such an injection device will be described with reference to FIG. FIG. 15 is a graph showing the injection speed, pressure, control method and the like in each step in the injection device of the die casting machine according to the third embodiment.

As soon as the molten metal is poured into the sleeve by the water heater, the injection filling process is started. First, the injection filling servomotor 212 is rotated at low speed to perform low speed injection. Then, when the plunger 210 moves forward by the set distance and the upper surface of the molten metal in the sleeve rises to the vicinity of the mold gate, the rotation of the injection filling servomotor 212 is accelerated at once to perform high speed injection. When the inside of the mold cavity is substantially filled with the molten metal, the injection speed is reduced to prevent the occurrence of shock (surge pressure) at the time of full filling. Since the injection pressure starts to rise sharply immediately before full filling in the mold cavity, when the measurement value of the injection pressure reaches the switching pressure, the pressure is switched to the pressure holding process. The injection pressure can be measured from the pressure of the molten metal in the mold, or can be measured by attaching a load cell to a plunger 210 or the like.
During the injection and filling process, the injection and filling servomotor 212 performs speed control, and the pressure raising servomotor 230 performs position holding control and is kept stationary. By performing position holding control of the pressure rising servomotor 230, the injection pressure during injection filling can be transmitted to the injection filling device and the plunger 210 via the pressure rising holding device.

After switching from the injection filling process to the pressure-rising holding process, the injection filling brake 221 is operated (ON) to restrain the rotation of the injection filling ball screw shaft 216. This is to prevent the injection filling ball screw 216 from rotating in the opposite direction due to the high molten metal pressure at the time of pressure increase, thereby preventing the plunger 210 from being retracted. In addition, after the injection filling brake 221 is actuated, the injection filling servomotor 212 is set to servo free (resting state).
In addition, after switching from the injection filling process to the pressure increase holding process, the pressure increase servomotor 230 is subjected to torque increase control according to the set pressure increase speed. At this time, when the injection pressure (molten metal pressure) rises and the forward force of the pressure-raising ball screw exceeds the contraction force at the time of attachment of the spring 240, the spring 240 is further contracted. Then, when the injection pressure reaches the set holding pressure, the holding brake 232 is turned on. When the holding brake 232 acts, the rotation of the ball screw shaft 236 is suppressed and the holding pressure is maintained, even if the pressure raising servomotor 230 is in the servo free state. During holding, the plunger 210 advances slightly as the molten metal in the mold cavity solidifies and contracts, but since the contraction of the spring 240 extends, the set pressure can be substantially maintained although the injection pressure slightly decreases.

As described above, the boosting servomotor 230 can be servo-free after the holding brake 232 is turned on, and the boosting time is usually 1 second or less, so the maximum instantaneous torque (about 250% of the rated torque) of the servomotor ) Can be used. Therefore, a servomotor with a small capacity can be adopted, and the manufacturing cost is reduced.
On the other hand, in the mechanism of Patent Document 2, since the brake is not attached, the servomotor needs to continuously exert the torque during the long time of the pressure rising and holding process, and the maximum momentary torque can not be used. Therefore, it is necessary to use a large capacity servomotor which can be boosted and held at the rated torque.

Further, since the reduction gear 233 can also be used with a small reduction ratio, the rotational speed of the ball screw shaft 236 can be increased without rotating the servomotor with large inertia to a high speed, and the pressure increase in a shorter time is also possible. It becomes possible.

When the set holding time elapses, the pressure rising holding process ends, and the operation of the injection filling brake 221 and the holding brake 232 is released (turned off), and the next mold opening and pushing out process is performed to perform a series of casting processes. .

In the conventional injection devices of Patent Documents 1 and 2, the servomotor is almost stopped in order to perform a constant holding time by the operation of the servomotor for pressure holding (pressure increasing) during pressure holding process. It is necessary to keep exerting a large torque. Also, in order to keep exerting a large torque, it is necessary to keep flowing a large current, so the servomotor generates heat, and a servomotor with a large capacity is installed to avoid it, or a large cooling fan Need to be attached.

On the other hand, according to the injection device of the die casting machine concerning a 3rd embodiment, the following advantageous effects can be produced.
(1) Since the step-up servomotor does not have to continuously exert a large torque during the holding time, it is not necessary to keep the current flowing for a long time, energy saving operation is possible, and the servomotor does not generate heat.
(2) Since the boosting servomotor only needs to exert a large torque instantaneously, a servomotor with a small capacity can be used.
(3) Even when a reduction gear is used to generate a large torque, the reduction ratio can be reduced, so there is no need to rotate the servo motor rotation axis with a large inertia moment to a high speed, and pressure can be increased in a short time. It becomes.

The injection device of the die casting machine according to the third embodiment can be put to practical use in a production plant that casts an aluminum product by the die casting machine, and can contribute to cost reduction and energy saving operation of the electric injection device.

Next, an injection device of a die casting machine according to a fourth embodiment of the present invention will be described based on FIG. 16 to FIG. FIG. 16 is a schematic view showing the structure of the injection device of the die casting machine according to the fourth embodiment.

A plunger 310 consisting of a plunger tip 310a and a plunger rod 310b is in a slidable state in a sleeve (not shown), and by advancing it can inject and fill the molten metal in the sleeve into the mold cavity. At that time, the tip surface of the plunger tip 310a receives metal pressure (injection pressure) from the molten metal. The plunger rod 310 b is integrally connected to the plunger member 312. The plunger member 312 is joined to the moving part of the surge pressure preventing cylinder 316 (ring-shaped cylinder), and the high speed moving member 314 can slide though a key but has a rotational movement. It is connected in the state of being restrained. A lock nut 330 (movement suppressing mechanism) is attached to the high speed moving member 314 via a lock nut bearing 331 in a state where the lock nut 330 is rotatably and axially restrained. A friction disk 315 is fixed to the high speed moving member 314 side of the lock nut 330 and constitutes a part of the lock nut 330. When pressure is applied to the hydraulic oil of the oil chamber of the surge pressure preventing cylinder 316, the plunger member 312 and the high speed moving member 314 abut, and a gap 313 of a certain distance is formed between the plunger member 312 and the friction disk 315. Is formed.

Two sets of cushion cylinders 318 are mounted on both sides of the high speed moving member 314. A cushion cylinder moving member 321 is attached to the cushion cylinder 318 via a spline 319 or a key in a slidable but rotationally restricted state. An injection filling ball screw nut 320 is integrally fastened to the cushion cylinder moving member 321 by a bolt. The injection filling ball screw shaft 322 screwed with the injection filling ball screw nut 320 is mounted and supported on the rear support member 340 via the injection filling bearing 323 in a rotatably and axially restrained state. The injection filling ball screw shaft 322 is further coupled to the rotation axis of the injection filling servomotor 325 by a coupling 324.
The injection filling apparatus described here is composed of an injection filling ball screw, an injection filling servomotor 325, etc., but a linear motor may be used.

A trapezoidal screw 332 screwed with the lock nut 330 is fixed to the pressure member 333 by a key 333a and a collar 333b. A pressurizing nut holder 335 integral with the pressurizing ball screw nut 336 is mounted in the pressurizing member 333 so as to be slidable through a key but restricted in rotation, and the spring 334 is in a compressed state. It is pressed to one side (right direction in the figure) by (a disc spring or a coil spring). A pressurizing ball screw shaft 337 screwed with the pressurizing ball screw nut 336 is supported by the pressurizing support 338 in a rotatably and axially restrained state by the rear support member 340. The booster ball screw shaft 337 is further connected to the rotation shaft of the booster servomotor 344 via the reduction gear 341, the brake 342, and the booster coupling 343. The non-rotating portions of the reduction gear 341, the brake 342, and the boosting servomotor 344 are fixed to the rear support member 340. The pressure-boosting ball screw is preferably a ball screw having a small rotational friction resistance, but in the case of a large machine on which a large load acts, a trapezoidal screw or the like may be used. Further, by means of the reduction gear 341, even if the boost servomotor 344 with a small rotational torque, a large rotational torque can be transmitted to the boost ball screw shaft 337. Therefore, the reduction gear 341 may not be provided.

FIG. 17 is a view of the mold periphery and the injection device as seen from the side (injection filling ball screw etc. are omitted), the molten metal is poured into the injection sleeve 355 and the state immediately before the injection filling step is shown. It represents. A mold clamping force is applied to the fixed mold 352 attached to the fixed platen 350 and the movable mold 353 attached to the movable platen 351 by a mold clamping device (not shown), and these movable mold 352 and the movable mold 353 And a cavity, which is a cast-shaped space, is formed therebetween. An injection sleeve 355 is mounted on the stationary platen 350 and the stationary mold 352 and is in communication with the cavity. Therefore, when the plunger 310 is advanced (left direction in the figure), the molten metal can be filled in the cavity.

The rear support member 340 is integral with the lower support frame 346 and the upper support frame 347 and is connected to the stationary platen 350. Therefore, the pressure that the plunger 310 receives from the molten metal during injection filling and pressure holding can be supported and supported.
The high-speed moving member 314 and the pressing member 333 can slide smoothly in the front-rear direction on the lower support frame 346 by the high-speed member linear guide 349 and the pressing member linear guide 348, respectively. It is supported in a constrained state in the direction.
FIG. 18 is a view from the arrow A of FIG. The high speed moving member 314 is supported by two sets of linear guides 349 for high speed moving member. Further, on both sides of the high speed moving member 314, the injection filling ball screw shaft 322 and the like are supported via a cushion cylinder.

FIG. 19 shows a hydraulic device in circuit connection with the oil chambers of two sets of cushion cylinders 318 via piping and hoses. With the switching valve 361 energized, hydraulic oil of an appropriate pressure is supplied from the hydraulic pressure source to the oil chamber of the cushion cylinder 318, and with the cushion cylinder moving member 321 pressed against the cylinder end, the switching valve 361 is demagnetized, Seal the pressure. Further, the hydraulic circuit branches halfway and is connected to the oil tank 362 via a relief valve 360 set to a predetermined pressure. Therefore, the moment the molten metal fully fills the mold cavity, the high-speed injection member 314 decelerates rapidly, but the hydraulic oil flows from the relief valve 360 to the tank so that the moving member 321 can stroke forward in the cushion cylinder 318 ( Can move Therefore, since the impact force acting on the injection filling ball screw, the bearing 323 and the coupling 324 due to the rapid deceleration is alleviated, they are not damaged. In addition, an appropriate pressure capable of resisting the melt pressure during high-speed injection filling is enclosed in the oil chamber of the cushion cylinder 318 so that the cushion cylinder moving member 321 does not stroke (move) during high-speed injection filling. There is a need.

FIG. 20 shows a hydraulic system in circuit connection with the oil chamber of the surge pressure prevention cylinder 316 (ring cylinder). The circuit from the surge pressure preventing cylinder 316 branches into three circuits along the way, and is connected to the tank 366 and the hydraulic pressure absorbing hydraulic cylinder 367 via a spring type accumulator 364 and a switching valve 365. The spring-type accumulator 364 is for temporarily evacuating the hydraulic fluid flowing from the surge pressure preventing cylinder 316 so that the pressure in the circuit does not rapidly increase. A tank 366 and a switching valve 365 are provided to appropriately replenish the hydraulic oil in the circuit. In the surge pressure absorbing hydraulic cylinder 367, the piston rod is integrally connected to the nut holder 368 and the ball screw nut 369 for hydraulic pressure. A ball screw shaft 370 screwed to the ball screw nut 369 is connected to the rotary shaft of the hydraulic servomotor 372 via a coupling 371 and supported by a bearing (not shown). Therefore, by controlling the rotation amount and torque of the hydraulic servomotor 372, the position of the piston rod and the pressure of the hydraulic oil can be controlled. As a result, the hydraulic fluid in the oil chamber of the surge pressure preventing cylinder 316 can be supplied and maintained at an appropriate pressure, and furthermore, can be evacuated at an appropriate speed and pressure. Therefore, after the molten metal is fully filled in the cavity, the plunger member 312 and the friction disk 315 can be gently brought into contact with each other at a low speed, and then the pressure can be released. By releasing the pressure, the normal force generated between the plunger member 312 and the friction disk 315 is increased, so that the friction force is also increased, and the rotation of the lock nut 330 can be restrained more reliably. This is because the action of the lead of the trapezoidal screw 332 exceeds the force for stopping the rotation of the lock nut 330 more than the force for stopping the rotation. By gently abutting the plunger member 312 and the friction disc 315, the surge pressure generated at that time can also be suppressed.

FIG. 21 is a view showing another example of the hydraulic device connected in circuit with the oil chamber of the surge pressure preventing cylinder 316. In FIG. The circuit from the surge pressure prevention cylinder 316 branches into three, and is connected to a tank 393 via a spring-type accumulator 384, a pump 386 via a check valve 385, and a flow control valve 391. The pump 386 is rotationally driven by the electric motor 387, sucks up the hydraulic fluid from the tank 388, and supplies the hydraulic fluid of appropriate pressure to the anti-surge pressure cylinder 316 by the relief valve 389. The flow control valve 391 can freely adjust the valve opening degree continuously and in a short time from 0 to full opening by the rotation operation of the servomotor 392. Therefore, the hydraulic oil in the oil chamber of the surge pressure prevention cylinder 316 is fed back to the tank 393 while appropriately controlling the pressure by feeding back the measured value of the pressure sensor 390 etc., and the plunger member 312 and the friction disc 315 are gently hit. It can be brought in contact and then the pressure released.

In the injection device of the die casting machine according to the fourth embodiment, the pressure rising and holding device is described as the structure for generating the holding force by the servomotor and the ball screw, but the holding force may be generated by the hydraulic cylinder. However, adjusting the boosting speed and the like by torque control of the servomotor is more excellent in the stability of the operation and the like.

Next, an injection filling process, a pressure holding process, and a control method thereof performed by such an injection apparatus will be described with reference to FIG. FIG. 22 is a graph showing the speed, pressure, and state of each device during the injection filling step and the pressure rising and holding step.

First, the state of the injection device before the start of the injection filling process will be described. Hydraulic fluid is supplied from the hydraulic pressure source 363 to the oil chamber of the cushion cylinder 318, and the cushion cylinder moving member 321 is moved to the cylinder end and held at an appropriate pressure. Also, an appropriate pressure is loaded on the surge pressure prevention cylinder 316 (ring cylinder). This pressure is made to correspond to the molten metal pressure to be switched from the injection filling process to the pressure raising process or slightly higher than that. The brake 342 is kept off.

As soon as the molten metal is poured into the injection sleeve by the water heater after completion of the clamping process, the injection filling process is started immediately. First, the injection filling servomotor 325 is rotated at low speed to perform low speed injection. Then, when the plunger 310 advances by a set distance and the upper surface of the molten metal in the sleeve rises to near the mold gate, the rotation of the injection filling servomotor 325 is accelerated at a stroke to carry out high speed injection. At this time, due to the rotational inertia of the injection filling ball screw shaft 322 and the coupling 324, an acceleration region (acceleration time) for increasing the speed to a high speed exists. During the injection and filling process, the pressure raising servomotor 344 performs position holding control so that the pressure member 333 and the like do not move. When the inside of the mold cavity is substantially filled with the molten metal, the pressure received from the molten metal by the plunger 310 becomes high, and when the switching pressure is reached, the pressure is switched to the pressure increasing process. The switching pressure may be detected by loading a load cell or the like into the plunger 310 or the plunger member 312, or the pressure of the surge pressure preventing cylinder 316 is set to be equivalent to the switching pressure, and the moving portion The moment of movement may be detected by a position sensor, movement of a spring-type accumulator 364 or pressure.

When switching to the pressure increase process, the injection filling servomotor 325 generates torque in the direction opposite to the rotation direction to stop the rotation. At this time, since the hydraulic oil from the oil chamber of the cushion cylinder 318 falls to the oil tank 362 via the relief valve 360, the cushion cylinder moving member 321 can make a stroke. Therefore, since a large pressure is not generated in the cushion cylinder 318, a large impact does not occur on the injection filling ball screw shaft 322, the bearing 323, and the coupling 324, and there is no breakage. In addition, since the rotational kinetic energy of the rotating body such as the injection filling ball screw shaft 322 does not act on the plunger 310 in an impacting manner, the generation of the burr due to the surge pressure can be prevented. Then, when the rotation of the injection filling ball screw shaft 322 or the like stops, the injection filling servomotor 325 is stopped to be in a free state.

At the same time after switching to the pressure raising process, the hydraulic oil in the oil chamber of the surge pressure preventing cylinder 316, the hydraulic servomotor 372, and the surge prevent the surge pressure from being generated in the molten metal The pressure absorbing hydraulic cylinder 367 or the flow control valve 391 is operated appropriately and the pressure is released at an appropriate pressure. Then, the plunger member 312 and the friction disc 315 are brought into contact at low speed without impact. Then, since the molten metal pressure from the plunger 310 exerts a frictional force on the contact surface, the rotation of the lock nut 330 is stopped and the relative movement between the lock nut 330 and the trapezoidal screw 332 is suppressed and locked.

In this state, the pressure raising servomotor 344 is driven to move the pressure member 333, the trapezoidal screw 332 and the plunger member 312 forward by torque control to raise the pressure of the molten metal and raise the pressure. The boost speed can be freely adjusted by torque control. At this time, the spring 334 is compressed by the pressing force. Then, when the pressure of the molten metal reaches a desired holding pressure, the brake 342 is operated to stop the rotation of the pressure rising ball screw shaft 337, and the pressure rising servomotor 344 is put in a free state to stop power consumption. . During the holding process, although the pressing force from the plunger 310 to the molten metal is maintained by the compression force of the spring 334, the holding pressure is slightly reduced because the plunger 310 advances since the molten metal solidifies and contracts.

Although the forward drive of the boosting servomotor 344 has been described as after the contact between the plunger member 312 and the friction disk 315, if it is desired to further increase the boosting speed, the forward operation may be started before the contact. .
Further, even if the spring 334 and the brake 342 are not attached, the holding pressure can be maintained as long as the boosting servomotor 344 continues to generate rotational torque during the holding process.

When the set holding time has elapsed, the holding process ends, and the operation of the brake 342 is released (OFF) to lower the holding pressure. Then, with the next mold opening, the injection filling servomotor 325 or the pressure rising servomotor 344 is driven to carry out the ejection process. When the cast product is removed from the mold, a series of casting processes are completed and the next casting process is started.

As mentioned above, according to the injection device of the die-cast machine which concerns on 4th Embodiment, there can exist the following advantageous effects.
(1) Since a large hydraulic tank and a hydraulic cylinder for injection are not required, the hydraulic circuit and the entire injection device can be simplified.
(2) Since the speed of the injection and filling process can be controlled by electrical control, the operation is stabilized and the freedom of setting the operating conditions is increased.
(3) The surge pressure can be prevented, and the generation of burrs in the cast product can be prevented.
(4) The injection filling device is not damaged by the impact of the reaction force of the surge pressure.

The injection device of the die casting machine according to the fourth embodiment can be put to practical use in a production plant that casts an aluminum product by the die casting machine, and can contribute to the improvement of cast product quality, simplification of the injection device, and energy saving operation.

The above-described first to fourth embodiments are examples of the present invention, and the present invention is not limited by the embodiments, and is defined only by the matters described in the claims, and other than the above. Embodiments are also feasible.

In the injection device of the die casting machine according to the first to fourth embodiments described above, the ball screw for injection filling preferably has a large lead angle, and the ball screw for boosting has a small lead angle. It is preferable to have
This is different from an injection device for resin molding in an injection device of a die casting machine, for example, as shown in FIG. 6, FIG. 13, FIG. 15, and FIG. This is because a high pressure holding capacity when the molten metal is filled is required.

10, 110, 210, 310 Plunger 12, 212, 325 Injection filling servomotor 13, 230, 344 Pressure boosting (holding) servomotor 16, 216, 322 Injection filling ball screw shaft 17, 217, 320 For injection filling Ball screw nut 25, 49, 63, 315 Friction disk 27, 236, 337 Ball screw shaft 28, 237, 336 for pressure holding and holding Ball screw nut 120 for pressure holding and holding 120 Surge pressure prevention device (hydraulic cylinder)
124 shock absorbing spring 221 injection filling brake 232 holding brake 313 gap 316 surge pressure prevention cylinder (ring-shaped cylinder)
318 cushion cylinder

Claims (27)

1. What is claimed is: 1. An injection device of a die casting machine for injecting and filling molten metal in a sleeve into a mold by advancing a plunger,
   An injection filling device for advancing the plunger at low speed and high speed by a motor;
   A pressure holding device for applying pressure to the molten metal through the plunger;
   An injection device of a die casting machine comprising: a movement suppressing mechanism which suppresses relative movement between the plunger and a moving portion of the pressure holding device during a period in which pressure is applied to the molten metal.
2. The movement suppression mechanism is a lock mechanism that suppresses relative movement between the plunger and the moving part of the pressure holding device by the pressure received from the molten metal when the pressure received from the molten metal from the molten metal is equal to or higher than a set pressure. The injection device of the die casting machine according to claim 1, characterized in that:
3. The said injection | pouring filling apparatus is driven by a servomotor and a screw, The injection apparatus of the die-cast machine of Claim 1 or 2 characterized by the above-mentioned.
4. The injection device of a die casting machine according to claim 1 or 2, wherein the injection filling device is driven by a linear motor.
5. The said pressure | voltage rise holding apparatus is driven by a servomotor and a screw, The injection device of the die-cast machine of any one of the Claims 1 thru | or 4 characterized by the above-mentioned.
6. The locking mechanism is characterized in that the relative movement of the plunger and the moving part of the pressure holding device is suppressed by suppressing the rotation of the screw nut by the frictional force by the pressure received from the molten metal by the plunger. The injection apparatus of the die-cast machine according to any one of claims 2 to 5.
7. The injection device of a die casting machine according to any one of claims 2 to 6, wherein the set pressure is set by an elastic force of a spring.
8. The said set pressure is set by the pressure of hydraulic fluid, The injection device of the die-cast machine of any one of the Claims 2 thru | or 6 characterized by the above-mentioned.
9. What is claimed is: 1. An injection device of a die casting machine for injecting and filling molten metal in a sleeve into a mold by advancing a plunger,
   Servo motor,
   A motion conversion device for converting the rotational motion of the servomotor into a linear motion;
   An injection device of a die casting machine comprising a surge pressure preventing device connected between a linear motion part of the motion converting device and the plunger.
10. 10. The injection device of a die casting machine according to claim 9, wherein a spring is built in the surge pressure preventing device, and the elastic deformation of the spring prevents the surge pressure.
11. The surge pressure prevention device comprises a hydraulic cylinder, a piston rod of the hydraulic cylinder is connected to a plunger, and a flow passage communicating the head chamber and the rod chamber in the hydraulic cylinder is provided inside the piston head and the piston rod 10. An injection apparatus for a die casting machine according to claim 9, wherein an orifice is formed in the middle of the flow path, and a spring in a compressed state is provided in the head chamber.
12. The surge pressure preventing device comprises a hydraulic cylinder, a piston rod of the hydraulic cylinder is connected to a plunger, and a flow passage communicating with the head chamber and the rod chamber in the hydraulic cylinder crosses halfway by an external flow passage. The injection device of a die casting machine according to claim 9, which is connected to an accumulator.
13. The surge pressure prevention device is composed of a double diameter rod hydraulic cylinder, and a piston rod on one side of the hydraulic cylinder is connected to a plunger, and a plunger side rod chamber and an anti plunger side rod in the hydraulic cylinder The flow passage leading to the chamber is connected in circuit via a check valve and a relief valve connected in parallel, and when the piston head moves to the plunger side, the hydraulic oil on the plunger side rod chamber is anti-plunger via the check valve It can flow into the side rod chamber without resistance, and when the piston head moves to the opposite side to the plunger, the hydraulic oil of the opposite plunger side rod chamber receives resistance through the relief valve and the opposite plunger side rod chamber The injection device of a die-casting machine according to claim 9, characterized in that:
14. The surge pressure prevention device comprises a hydraulic cylinder, a rod of the hydraulic cylinder is connected to a plunger, a head chamber in the hydraulic cylinder is connected in circuit with a head chamber of a hydraulic pressure absorbing hydraulic cylinder, and the surge pressure is absorbed 10. The injection device of a die-casting machine according to claim 9, wherein the piston rod of the hydraulic cylinder is movable back and forth by means of a servomotor and a ball screw.
15. The surge pressure prevention device comprises a hydraulic cylinder, a rod of the hydraulic cylinder is connected to a plunger, and a head chamber in the hydraulic cylinder is connected to a tank through a flow control valve capable of continuously adjusting the flow rate. The injection device of the die casting machine according to claim 9, characterized in that:
16. The pressure rising and holding device includes a servo motor, a ball screw for converting the rotational movement of the servo motor into a linear movement, a compression spring for transmitting an advancing force of the linear portion of the ball screw to the plunger, the servo motor, and And a brake mounted between the ball screws and capable of suppressing rotational movement of the ball screws,
    The injection filling device includes a ball screw that converts rotational motion of the motor into linear motion;
    The movement suppressing mechanism is a brake which is mounted between a motor of the injection filling device and a ball screw of the injection filling device and which can suppress rotational movement of the ball screw.
    In the pressure holding step, the pressure of the molten metal is increased while compressing the compression spring by the rotational movement of the servomotor, and after the pressure increase, the brake is operated to suppress the rotational movement of the ball screw, thereby compressing the spring. The injection device of a die casting machine according to claim 1, wherein the pressure of the molten metal can be maintained by
17. 17. The injection device of a die casting machine according to claim 16, wherein a reduction gear is mounted between the brake of the pressure rising and holding device and the ball screw of the pressure rising and holding device.
18. A plunger member integrally coupled with the plunger;
    A high speed moving member connected to the plunger member via a surge pressure preventing cylinder;
    The movement restraining mechanism is mounted on the high speed moving member via a bearing, and is screwed with a trapezoidal screw, and is in contact with the plunger member by pressure received by the plunger and is relative to the trapezoidal screw. A lock nut whose motion is constrained,
    In the injection filling device, a moving part is connected to the high speed moving member via a cushion cylinder,
    The pressure rising and holding device is configured to press the trapezoidal screw and apply a holding force to the molten metal from the plunger through the lock nut and the plunger member. Die casting machine injection device.
19. 19. The injection filling apparatus according to claim 18, further comprising an injection filling servomotor and an injection filling ball screw, wherein a nut portion of the injection filling ball screw is integral with a moving portion of the cushion cylinder. The injection device of the die-cast machine described.
20. 19. The injection device of a die casting machine according to claim 18, wherein the pressure rising and holding device comprises a pressure rising servomotor and a pressure rising ball screw.
21. The pressure rising and holding device is provided between the pressure rising servomotor and the pressure rising ball screw, and the rotational motion of the pressure rising ball screw transmits the forward force of the nut portion of the pressure rising ball screw to the trapezoidal screw. Equipped with a brake that can deter
    In the pressure raising and holding step, the pressure increase of the molten metal pressure is performed while compressing the compression spring by the rotation operation of the pressure rising servomotor, and after pressure rising, the brake is operated to suppress the rotation movement of the pressure rising ball screw. The injection device of a die casting machine according to claim 20, wherein the pressure of the molten metal can be held by the compression force of the compression spring.
22. The injection device of a die casting machine according to claim 18, wherein the hydraulic oil in the oil chamber of the cushion cylinder is controlled not to rise above a predetermined pressure by a relief valve connected in circuit.
23. The oil chamber of the surge pressure preventing cylinder is connected in circuit to a surge pressure absorbing hydraulic cylinder, and the piston rod of the surge pressure absorbing hydraulic cylinder is moved by a hydraulic ball screw and a hydraulic servomotor, the surge The injection device of a die casting machine according to claim 18, characterized in that the position and pressure of the moving part of the pressure preventing cylinder can be controlled.
24. The oil chamber of the surge pressure preventing cylinder is in circuit connection with a flow rate adjusting valve, and the flow rate adjusting valve can control the position and pressure of the moving part of the surge pressure preventing cylinder. Die casting machine injection device described in.
25. A control method for operating an injection device of a die casting machine according to claim 1 or 2, wherein
    In the injection and filling process for low speed and high speed advancement, the injection filling device performs speed control and the pressure rising and holding device performs position holding control,
    The die-cast machine is characterized in that the injection filling device carries out pressure control or position holding control and the pressure holding device carries out pressure control in the pressurization holding step after the pressure received from the molten metal from the molten metal reaches the switching pressure. Control method of the injection device.
26. The method for controlling an injection apparatus of a die-cast machine according to claim 16 or 17, wherein the brake is operated after the pressure of the molten metal is increased, and then the servomotor is brought into a free state.
27. The injection device of the die casting machine according to claim 18, wherein after switching from the injection filling step to the pressure increase step, the pressure in the oil chamber of the surge pressure preventing cylinder is adjusted to control the contact speed of the plunger member and the lock cylinder. Method of controlling an injection device of a die casting machine characterized by

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