JP7057707B2 - Injection device and molding machine - Google Patents

Description

The present disclosure relates to an injection device and a molding machine. The molding machine is, for example, a die casting machine or an injection molding machine.

As an injection device, a plunger that pushes a molding material into a mold is known to be driven by an injection cylinder (for example, Patent Document 1). The injection cylinder has an injection piston rod connected to a plunger, an injection piston fixed to the injection piston rod, and an injection cylinder portion for accommodating the injection piston. The inside of the injection cylinder portion is divided into an injection rod side chamber on the side where the injection piston rod extends by the injection piston and an injection head side chamber on the opposite side. Then, when the hydraulic fluid (for example, oil) is supplied to the injection head side chamber, the injection piston moves to the injection piston rod side, whereby the plunger advances toward the mold. The speed of the injection cylinder (in other words, the injection speed) is controlled by, for example, a flow rate control valve (meter-out circuit) that controls the flow rate of the hydraulic fluid discharged from the injection rod side chamber (for example, Patent Document 1).

In addition, Patent Document 1 discloses an accumulator connected to the injection rod side chamber in order to suppress the surge pressure. Further, although not particularly exemplified, as an injection cylinder, a cylinder having a pressure boosting piston capable of increasing the pressure in the injection head side chamber is known.

Japanese Unexamined Patent Publication No. 6-297128

Ideally, when a meter-out circuit is used, the injection piston advances at a speed corresponding to the flow rate of the hydraulic fluid discharged from the injection rod side chamber. However, in reality, for example, when the supply of the hydraulic fluid to the injection head side chamber is started, the hydraulic fluid in the injection rod side chamber is compressed by the pressure applied to the hydraulic fluid in the injection rod side chamber from the injection piston, and the injection rod side chamber is compressed. The injection piston may move forward at a speed exceeding the speed corresponding to the flow rate of the hydraulic fluid discharged from the. That is, so-called jumping may occur. As a result, the quality of the molded product may deteriorate.

Therefore, it is preferable to provide an injection device and a molding machine that can realize at least one of reduction of jumping risk and improvement of boosting performance.

The injection device according to one aspect of the present disclosure includes an injection cylinder that drives a plunger that pushes a molding material into a front mold, a hydraulic device that controls the flow of hydraulic fluid in the injection cylinder, and the hydraulic device. The injection cylinder has a control device for controlling, and the injection cylinder slides the injection piston rod connected to the rear portion of the plunger, the injection piston fixed to the rear portion of the injection piston rod, and the injection piston. An injection cylinder portion that is movably housed and whose inside is divided into a front injection rod side chamber and a rear injection head side chamber by the injection piston, and a small-diameter cylinder portion that communicates with the injection head side chamber. A large-diameter cylinder portion that is connected in series to the small-diameter cylinder portion and has a larger diameter than the small-diameter cylinder portion, a small-diameter piston slidably housed in the small-diameter cylinder portion, and a small-diameter piston fixed in series to the small-diameter piston portion. The large-diameter cylinder portion is slidably housed in the large-diameter cylinder portion, and the inside of the large-diameter cylinder portion is divided into a pressure-increasing rod side chamber on the small-diameter cylinder portion side and a pressure-increasing head side chamber on the opposite side. The control device has a large-diameter piston, and the control device supplies a hydraulic fluid to the pressure-increasing head side chamber to apply hydraulic pressure from the pressure-increasing rod side chamber to the injection rod side chamber before the start of injection. It has a pressure control unit that controls the hydraulic pressure device so as to apply pressure.

In one example, the pressurization control unit controls the hydraulic device so as to release pressure from the injection head concubine at the time of pressurization.

In one example, the injection cylinder has a stopper fixed to the injection cylinder portion to regulate the retreat of the injection piston.

In one example, the small-diameter cylinder portion continues in series with respect to the rear side of the injection cylinder portion, the inner diameter of the small-diameter cylinder portion is smaller than the inner diameter of the injection cylinder portion, and the injection cylinder portion and the small-diameter cylinder portion. The stopper is configured by a step between the portions.

In one example, the pressure receiving area S3 of the large-diameter piston in the pressure increasing head side chamber with respect to the ratio S1 / S2 of the pressure receiving area S1 of the injection piston in the injection head side chamber to the pressure receiving area S2 of the injection piston in the injection rod side chamber. The ratio (S3 / S4) / (S1 / S2) of the ratio S3 / S4 to the pressure receiving area S4 in the pressure increasing rod side chamber of the large-diameter piston is 0.9 or more and 1.2 or less.

In one example, the hydraulic pressure device has a flow rate control valve that controls the flow rate of the hydraulic fluid discharged from the injection rod side chamber, and the control device supplies the hydraulic fluid to the injection head side chamber and said. The injection control unit that controls the hydraulic pressure device to start injection by opening the flow control valve, and the hydraulic pressure device that controls the hydraulic pressure device to increase the pressure by supplying the hydraulic fluid to the pressure increasing head side chamber. It has a pressure boosting control unit.

In one example, the injection device further has an electric drive unit capable of driving the injection piston rod with respect to the injection cylinder portion, and in the hydraulic device, the pressure in the injection rod side chamber is a predetermined pressure. The control device includes a relief valve that discharges the hydraulic fluid from the injection rod side chamber when the pressure exceeds the above, and a flow control valve that controls the flow rate of the hydraulic fluid discharged from the injection rod side chamber. The low-speed injection is started by the driving force of the electric drive unit, and then the hydraulic fluid is supplied to the injection head side chamber and the flow control valve is opened to perform high-speed injection at a higher speed than the low-speed injection. An electric drive unit, an injection control unit that controls the hydraulic pressure device, and a pressure boosting control unit that controls the hydraulic pressure device so as to increase the pressure by supplying a hydraulic fluid to the pressure boosting head side chamber. Have.

In one example, the hydraulic pressure device has an accumulator that supplies a hydraulic fluid to the pressure boosting head side chamber, and a pressure boosting side flow control valve that controls the flow rate of the hydraulic fluid discharged from the pressure boosting rod side chamber. The control device includes a head control unit that controls the hydraulic device so as to continuously supply a hydraulic fluid from the accumulator to the pressure boosting head side chamber from the pressurization to the completion of the pressure boosting, and the pressure boosting side flow rate. It has a pressure boosting control unit that controls the hydraulic pressure device so as to start the pressure boosting by opening the control valve.

The injection device according to one aspect of the present disclosure includes an injection cylinder that drives a plunger that pushes a molding material into a front mold, a hydraulic device that controls the flow of hydraulic fluid in the injection cylinder, and the hydraulic device. It has a control device for controlling, and the injection cylinder slides the injection piston rod connected to the rear part of the plunger, the injection piston fixed to the rear part of the injection piston rod, and the injection piston. An injection cylinder portion that is movably housed and whose inside is divided into a front injection rod side chamber and a rear injection head side chamber by the injection piston, and a small diameter cylinder portion that communicates with the injection head side chamber. A large-diameter cylinder portion that is connected in series to the small-diameter cylinder portion and has a larger diameter than the small-diameter cylinder portion, a small-diameter piston slidably housed in the small-diameter cylinder portion, and a small-diameter piston fixed in series to the small-diameter piston portion. The large-diameter cylinder portion is slidably housed in the large-diameter cylinder portion, and the inside of the large-diameter cylinder portion is divided into a pressure-increasing rod side chamber on the small-diameter cylinder portion side and a pressure-increasing head side chamber on the opposite side. The hydraulic device has an accumulator that supplies the hydraulic fluid to the pressure boosting head side chamber and a pressure boosting side that controls the flow rate of the hydraulic fluid discharged from the pressure boosting rod side chamber. It has a flow control valve, and the control device controls the hydraulic device so as to continuously supply the hydraulic fluid from the accumulator to the booster head side chamber from before the start of boosting to the completion of boosting. It has a head control unit for controlling the pressure increase and a pressure increase control unit for controlling the hydraulic pressure device so as to start the pressure increase by opening the pressure increase side flow control valve.

In one example, the hydraulic device has a pressurizing valve capable of allowing and prohibiting the flow of hydraulic fluid from the pressure boosting rod side chamber to the injection rod side chamber, and the control device has a pressurization valve before the start of injection. It has a pressurization control unit that controls the pressurization valve so as to apply hydraulic pressure from the pressurization rod side chamber to the injection rod side chamber.

In one example, the hydraulic pressure device has a flow rate control valve that controls the flow rate of the hydraulic fluid discharged from the injection rod side chamber, and the pressure increase control unit controls the flow rate control valve over the pressure increase. The hydraulic pressure device is controlled so as to be fully opened.

The molding machine according to one aspect of the present disclosure includes the above-mentioned injection device, a mold-clamping device for mold-clamping the mold, and an extrusion device for extruding a molded product from the mold.

According to the above configuration, at least one of reduction of jumping risk and improvement of boosting performance can be realized.

The schematic diagram which shows the structure of the die casting machine which has the injection apparatus which concerns on 1st Embodiment of this disclosure. The schematic diagram which shows the structure of the hydraulic pressure system in the injection apparatus of FIG. 3 (a) to 3 (c) are schematic cross-sectional views showing a part of the injection cylinder in an enlarged manner. The timing chart for demonstrating the operation of the injection apparatus of FIG. The schematic diagram which shows the structure of the drive mechanism in the injection apparatus which concerns on 2nd Embodiment of this disclosure. The schematic diagram which shows the structure of the hydraulic pressure system in the injection apparatus of FIG. The timing chart for demonstrating the operation of the injection apparatus of FIG. 8 (a) and 8 (b) are schematic views showing a modified example of the injection cylinder. The schematic diagram which shows the main part structure of the injection apparatus which concerns on 3rd Embodiment of this disclosure. The timing chart for demonstrating the operation of the injection apparatus of FIG.

Hereinafter, embodiments and modifications thereof according to the present disclosure will be described with reference to the drawings. In the description of the second embodiment or the modified example, basically, only the difference from the already described embodiment (basically the first embodiment) will be described. The points not particularly mentioned may be the same as those described above. Further, with respect to the configuration which is the same as or similar to the configuration of the embodiment already described, a reference numeral attached to the configuration of the embodiment already described may be added.

<First Embodiment>
(Overall configuration of die casting machine)
FIG. 1 is a side view showing a configuration of a main part of the die casting machine 1 according to the first embodiment of the present disclosure, including a cross-sectional view in part.

The die casting machine 1 injects a molten metal material (molten metal) into a mold 101 (a space such as a cavity Ca; the same applies hereinafter) and solidifies the molten metal in the mold 101 to perform die casting. It manufactures products (molded products). The metal is, for example, aluminum or an aluminum alloy.

The mold 101 includes, for example, a fixed mold 103 and a moving mold 105. In the description of the present embodiment, for convenience, the cross section of the fixed mold 103 or the moving mold 105 is shown by one type of hatching, but these molds may be of a direct carving type or a nested type. It may be a thing. Further, the fixed mold 103 and the moving mold 105 may be combined with a core or the like.

The die casting machine 1 has, for example, a machine main body 3 that performs a mechanical operation for molding, and a control unit 5 that controls the operation of the machine main body 3.

The machine main body 3 includes, for example, a mold clamping device 7 that opens and closes and clamps the mold 101, an injection device 9 that injects molten metal into the mold 101, and a die-cast product fixed mold 103 or a moving mold 105 (. FIG. 1 has an extrusion device 11 for extruding from a moving die 105). In the machine main body 3, the configurations other than the injection device 9 (for example, the configurations of the mold clamping device 7 and the extrusion device 11) may be the same as various known configurations.

In the molding cycle, the mold clamping device 7 moves the moving mold 105 toward the fixed mold 103 to close the mold. Further, the mold clamping device 7 applies a mold clamping force corresponding to the extension amount of the tie bar (reference numeral omitted) to the mold 101 to perform mold clamping. A cavity Ca having the same shape as the molded product is formed in the mold 101 that has been molded. The injection device 9 injects and fills the molten metal into the cavity Ca. The molten metal filled in the cavity Ca is deprived of heat by the mold 101, cooled, and solidified. As a result, a molded product is formed. After that, the mold clamping device 7 moves the moving mold 105 in a direction away from the fixed mold 103 to open the mold. At this time, or after that, the extruder 11 extrudes the molded product from the moving die 105.

The control unit 5 includes, for example, a control device 13 (see FIG. 2) that performs various operations and outputs a control command, a display device 15 that displays an image, and an input device 17 that accepts an operator's input operation. ing. From another viewpoint, the control unit 5 has, for example, a control panel (not shown) having a power supply circuit, a control circuit, and the like, and an operation unit 19 as a user interface.

The control device 13 is provided, for example, in a control panel and an operation unit 19 (not shown). The control device 13 may be appropriately divided or dispersed. For example, the control device 13 includes a lower control device for each of the mold clamping device 7, the injection device 9, and the extrusion device 11, and a higher control device that performs control such as synchronization between the lower control devices. May be configured.

The display device 15 and the input device 17 are provided in, for example, the operation unit 19. The operation unit 19 is provided, for example, in a fixed portion of the mold clamping device 7. The display device 15 is composed of, for example, a touch panel including a liquid crystal display or an organic EL display. The input device 17 is composed of, for example, a mechanical switch and the touch panel described above.

(Configuration of injection device)
The injection device 9 has, for example, a sleeve 21 that leads to the inside of the mold 101, a plunger 23 that is slidable in the sleeve 21, and an injection drive unit 25 that drives the plunger 23. In the description of the injection device 9, the mold 101 side may be referred to as the front side, and the opposite side may be referred to as the rear side.

The sleeve 21 is, for example, a tubular member connected to the fixed mold 103, and a supply port 21a for receiving the molten metal into the sleeve 21 is opened on the upper surface thereof. The plunger 23 has a plunger tip 23a that can slide in the sleeve 21 in the front-rear direction, and a plunger rod 23b whose tip is fixed to the plunger tip 23a.

When the two members are fixed in the description of the present disclosure, the two members may be fixed by being integrally formed or joined to each other unless otherwise specified. Alternatively, they may be separably connected by screws or the like.

When the mold 101 is completed by the mold clamping device 7, one shot of molten metal is poured into the sleeve 21 from the supply port 21a by a hot water supply device (not shown). Then, the plunger 23 slides forward in the sleeve 21 from the position shown in the figure, so that the molten metal in the sleeve 21 is pushed out (injected) into the mold 101.

(Structure of injection drive unit)
FIG. 2 is a schematic diagram showing the configuration of the injection drive unit 25.

As shown in FIGS. 1 and 2, the injection drive unit 25 is, for example, a hydraulic type, and supplies an injection cylinder 27 connected to the plunger 23 and a hydraulic fluid (for example, oil) to the injection cylinder 27. It has a hydraulic pressure device 28 (FIG. 2) to perform.

(Composition of injection cylinder)
3 (a) to 3 (c) are schematic cross-sectional views showing a part of the injection cylinder 27 in an enlarged manner. Note that FIGS. 3 (a) to 3 (c) show different operating states of the injection cylinder 27.

As shown in FIGS. 2 and 3 (a) to 3 (c), the injection cylinder 27 is composed of, for example, a so-called direct-coupled booster cylinder. Specifically, for example, the injection cylinder 27 is fixed to an injection cylinder portion 29, an injection piston 31 slidable inside the injection cylinder portion 29, and an injection piston 31 and extends from the injection cylinder portion 29. It has a rod 32, a pressure boosting cylinder portion 33 communicating with the injection cylinder portion 29, and a pressure boosting piston 35 slidable inside the pressure boosting cylinder portion 33.

The injection cylinder portion 29 is, for example, a cylindrical body having a circular internal cross-sectional shape. The injection piston 31 is, for example, substantially cylindrical. Inside the injection cylinder portion 29, the injection rod side chamber 29r on the side (front) where the injection piston rod 32 extends by the injection piston 31 and the injection head side chamber 29h on the opposite side (rear) (reference numeral is FIG. 3C). ) And. By selectively supplying the hydraulic fluid to the injection head side chamber 29h and the injection rod side chamber 29r, the injection piston 31 moves in the injection cylinder portion 29 in the front-rear direction.

Depending on the configuration of the injection cylinder 27, when the injection piston 31 is located at the retreat limit (FIGS. 2, FIGS. 3 (a) and 3 (b)), the volume of the injection head side chamber 29h becomes 0. Or it becomes close to 0. In the description of the present disclosure, for convenience, such a state may be expressed as if the injection head side chamber 29h exists.

The pressure boosting cylinder portion 33 is connected in series (for example, coaxially) behind the small diameter cylinder portion 33a with the small diameter cylinder portion 33a leading to the injection head side chamber 29h, and has a large diameter having a larger inner diameter than the small diameter cylinder portion 33a. It has a cylinder portion 33b. The small-diameter cylinder portion 33a and the large-diameter cylinder portion 33b are cylindrical bodies having a circular internal cross-sectional shape, respectively. The small-diameter cylinder portion 33a is provided, for example, at the rear end of the injection cylinder portion 29 so as to be continuous in series (for example, coaxially), so that the inside thereof leads to the injection head side chamber 29h.

Since FIGS. 3 (a) to 3 (c) are schematic views, one hatch is attached to the injection cylinder portion 29 and the pressure boosting cylinder portion 33, but in reality, a plurality of members are provided. May be connected to form an injection cylinder portion 29 and a pressure boosting cylinder portion 33. The seams of the plurality of members may or may not coincide with the boundary between the injection cylinder portion 29 and the pressure boosting cylinder portion 33. Further, since FIGS. 3 (a) to 3 (c) are schematic views, the injection cylinder portion 29 and the pressure boosting cylinder portion 33 are shown with a constant thickness, but in reality, the thickness varies depending on the portion. May be different. The same applies to other drawings described later.

The pressure boosting piston 35 is fixed in series (for example, coaxially) with the small diameter piston 35a capable of sliding the small diameter cylinder portion 33a and the small diameter piston 35a, and the large diameter piston 35b slidable with the large diameter cylinder portion 33b. And have. The small-diameter piston 35a and the large-diameter piston 35b are, for example, substantially cylindrical, respectively. Inside the large-diameter cylinder portion 33b, the pressure-increasing rod side chamber 33r on the small-diameter cylinder portion 33a side and the pressure-increasing head side chamber 33h on the opposite side (reference numerals are FIG. 3B) and FIG. )) And.

Depending on the configuration of the injection cylinder 27, when the pressure boosting piston 35 is located at the retreat limit (FIGS. 2 and 3 (a)), the volume of the pressure booster head side chamber 33h becomes 0 or is close to 0. Become. In the description of the present disclosure, for convenience, such a state may be expressed as if the pressure boosting head concubine 33h exists.

When the pressure increasing rod side chamber 33r is depressurized, the pressure receiving area of the large diameter piston 35b in the pressure increasing head side chamber 33h is larger than the pressure receiving area in the small diameter cylinder portion 33a of the small diameter piston 35a. It is possible to apply a pressure higher than the pressure received from the hydraulic fluid in the pressure increasing head side chamber 33h to the hydraulic fluid in the small diameter cylinder portion 33a and the injection head side chamber 29h. As a result, the injection cylinder 27 exerts a pressure increasing function of applying a hydraulic pressure higher than the applied hydraulic pressure to the back of the injection piston 31.

The pressure receiving area of the piston referred to in the description of the present embodiment is an area obtained by projecting the area in which the pressure of the working fluid acts on the piston in the moving direction (axial direction) of the piston. Therefore, the pressure receiving area is basically unaffected by the unevenness of the surface of the piston exposed to the cylinder chamber. Further, unless the shape of the piston is peculiar, the pressure receiving area is substantially the same as the cross-sectional area of the piston. If the piston is a cylinder with a diameter d, the pressure receiving area is π × (d / 2) ² .

The inner diameter of the small diameter cylinder portion 33a is made smaller than the inner diameter of the injection cylinder portion 29 (injection head side chamber 29h), for example. As a result, a step is formed between the injection cylinder portion 29 and the pressure boosting cylinder portion 33. This step functions as a stopper 36 (reference numeral is FIGS. 3A to 3C) that abuts on the injection piston 31 from the rear to regulate the retreat of the injection piston 31 (defines the retreat limit). .. The stopper 36 comes into contact with, for example, the outer peripheral side portion of the rear end surface of the injection piston 31 over the entire circumference.

As shown in FIG. 1, the injection cylinder 27 is arranged coaxially with, for example, the plunger 23. The tip of the injection piston rod 32 is connected to the rear end of the plunger 23 via a coupling (reference numeral omitted). The injection cylinder portion 29 is fixedly provided with respect to a mold clamping device (not shown) or the like. Therefore, the plunger 23 moves forward or backward in the sleeve 21 due to the movement of the injection piston 31 with respect to the injection cylinder portion 29.

(Principle of jumping suppression)
In the above configuration, for example, the hydraulic fluid is supplied to the injection head side chamber 29h, and the injection piston 31 advances to perform injection. The speed of the injection piston 31 is controlled, for example, by adjusting the flow rate of the hydraulic fluid discharged from the injection rod side chamber 29r. That is, the injection speed is controlled by the meter-out circuit.

In such a case, it corresponds to the flow rate of the hydraulic fluid discharged from the injection rod side chamber 29r due to the compression of the hydraulic fluid in the injection rod side chamber 29r when the supply of the hydraulic fluid to the injection head side chamber 29h is started. The injection piston 31 may be driven (jumping occurs) at a speed exceeding the speed.

Therefore, in the present embodiment, for example, before supplying the hydraulic fluid to the injection head side chamber 29h, the hydraulic fluid in the injection rod side chamber 29r is compressed in advance, thereby reducing the possibility of jumping.

Specifically, before the start of injection, the pressure increasing head is allowed to flow from the pressure increasing rod side chamber 33r to the injection rod side chamber 29r, and the discharge of the hydraulic fluid is prohibited for these two cylinder chambers as a whole. The hydraulic fluid is supplied to the side chamber 33h. As a result, the pressure boosting piston 35 advances with a relatively small movement amount δ (FIG. 3B), and the hydraulic fluids in the pressure boosting rod side chamber 33r and the injection rod side chamber 29r are compressed. At this time, the small diameter cylinder portion 33a is, for example, depressurized.

Since the pressure-receiving area of the large-diameter piston 35b in the pressure-increasing rod side chamber 33r is smaller than the pressure-receiving area of the large-diameter piston 35b in the pressure-increasing head side chamber 33h, the large-diameter piston 35b receives pressure from the hydraulic fluid in the pressure-increasing head side chamber 33h. It is possible to apply a higher pressure to the hydraulic fluid of the booster rod side chamber 33r.

Specifically, as shown in FIG. 3C, the pressure receiving area of the large diameter piston 35b in the pressure increasing head side chamber 33h is S3, and the pressure receiving area of the large diameter piston 35b in the pressure increasing rod side chamber 33r is S4 (<S3). Then, the large-diameter piston 35b can apply the pressure of the pressure increasing head side chamber 33h to the pressure increasing rod side chamber 33r by multiplying it by S3 / S4. Strictly speaking, the ratio of the pressure in the booster head side chamber 33h to the pressure in the booster rod side chamber 33r is affected by the sliding resistance of the booster piston 35, etc. Such effects may be ignored.

Here, the pressure receiving area of the injection piston 31 in the injection rod side chamber 29r is reduced by the injection piston rod 32. That is, the injection piston 31 has a larger pressure receiving area in the injection head side chamber 29h than the pressure receiving area in the injection rod side chamber 29r. Therefore, the injection piston 31 can increase the pressure in the injection head side chamber 29h to exert a pressure increasing action on the injection rod side chamber 29r. This pressure-increasing action is also one of the causes of jumping. Therefore, for example, the pressure-increasing action of the pressure-increasing piston 35 on the pressure-increasing rod side chamber 33r is equal to or greater than or equal to the pressure-increasing effect of the injection piston 31, or is greater than the pressure-increasing effect of the injection piston 31. good.

Specifically, for example, as shown in FIG. 3C, the pressure receiving area of the injection piston 31 in the injection head side chamber 29h is S1, and the pressure receiving area of the injection piston 31 in the injection rod side chamber 29r is S2 (<S1). .. Further, for example, when the difference between the two pressure increasing ratios is about 10%, it is considered that the two pressure increasing ratios are almost the same. At this time, the area ratio S3 / S4 may be, for example, 0.9 times or more and 1.1 times or less (that is, equivalent) of the area ratio S1 / S2. Further, for example, the area ratio S3 / S4 may be 0.9 times or more (that is, equivalent or more) the area ratio S1 / S2. Further, for example, the area ratio S3 / S4 may be 1.1 times or more and 1.2 times or less the area ratio S1 / S2. Further, for example, by combining these, the area ratio S3 / S4 may be 0.9 times or more and 1.2 times or less the area ratio S1 / S2.

As shown in FIG. 3A, the diameter of the injection piston 31 is d1, the diameter of the injection piston rod 32 is d2, the diameter of the large diameter piston 35b is d3, and the diameter of the small diameter piston 35a is d4. Further, it is assumed that each of these shapes is a cylindrical shape. In this case, in the embodiment in which S1 / S2 and S3 / S4 are substantially equivalent, d1 / d2 and d3 / d4 are substantially equivalent.

(Configuration of hydraulic pressure device)
The hydraulic pressure device 28 may have an appropriate configuration as long as it is possible to raise the pressure of the injection rod side chamber 29r in advance by the pressure boosting piston 35 in addition to the normal injection operation. An example thereof will be described below.

As shown in FIG. 2, the hydraulic pressure device 28 includes, for example, a tank 37 for storing the hydraulic fluid, a pump 39 capable of delivering the hydraulic fluid of the tank 37, and an accumulator 41 capable of discharging the accumulated hydraulic fluid. A plurality of flow paths (43A to 43H, etc.) connecting these and the injection cylinder 27 to each other, and a plurality of valves (45, 47, 49, 51, 53, 54 and 55) and.

The tank 37 is, for example, an open tank and holds the hydraulic fluid under atmospheric pressure. The tank 37 supplies the hydraulic fluid to the injection cylinder 27 via, for example, the pump 39 and the accumulator 41, and also houses the hydraulic fluid discharged from the injection cylinder 27.

The pump 39 is driven by the pump motor 40 to deliver the hydraulic fluid. The pump 39 may be of an appropriate type such as a rotary pump, a plunger pump, a constant capacity pump, a variable capacity pump, a one-way pump, and a bidirectional (two-way) pump. The pump motor 40 may be of an appropriate type such as a DC motor, an AC motor, an induction motor, a synchronous motor, a servo motor, or the like. The pump 39 (pump electric motor 40) may be constantly driven while the die casting machine 1 is in operation, or may be driven only when necessary. The pump 39 contributes to, for example, the supply of the hydraulic fluid to the accumulator 41 (accumulation of the accumulator 41) and the supply of the hydraulic fluid to the injection cylinder 27.

The accumulator 41 is, for example, a weight type, a spring type, a gaseous pressure type (including a pneumatic type), a cylinder type or a Prada type. In the illustrated example, the accumulator 41 is of a cylinder type and has a cylinder portion 41a and a piston 41b that divides the cylinder portion 41a into a liquid chamber 41e and a gas chamber 41f. The liquid chamber 41e contains a hydraulic fluid, and the gas chamber 41f is filled with a gas (for example, air or nitrogen). The hydraulic fluid is supplied to the liquid chamber 41e, and the piston 41b moves to the gas chamber 41f side, so that the gas in the gas chamber 41f is compressed and the accumulator 41 is accumulating pressure. Further, the hydraulic fluid is discharged from the liquid chamber 41e by utilizing the pressure of the gas. The accumulator 41 contributes, for example, to the supply of the hydraulic fluid to the injection cylinder 27.

The first flow path 43A connects the pump 39 and the accumulator 41 (liquid chamber 41e). Thereby, for example, the hydraulic fluid can be supplied from the pump 39 to the accumulator 41 to accumulate the pressure of the accumulator 41.

The second flow path 43B connects the accumulator 41 (liquid chamber 41e) and the injection head side chamber 29h. Thereby, for example, the hydraulic fluid can be supplied from the accumulator 41 to the injection head side chamber 29h to advance the injection piston 31.

The third flow path 43C connects the accumulator 41 (liquid chamber 41e) and the pressure increasing head side chamber 33h. Thereby, for example, the hydraulic fluid can be supplied from the accumulator 41 to the pressure increasing head side chamber 33h, and the pressure increasing action by the pressure increasing piston 35 can be obtained.

The fourth flow path 43D connects the injection rod side chamber 29r and the tank 37. Thereby, for example, the hydraulic fluid of the injection rod side chamber 29r whose volume decreases as the injection piston 31 advances can be discharged to the tank 37.

One end of the fifth flow path 43E is connected to the injection rod side chamber 29r, and the other end is connected to the pump 39 or the tank 37 by an auxiliary valve 51 described later.

One end of the sixth flow path 43F is connected to the injection head side chamber 29h, and the other end is connected to the pump 39 or the tank 37 by an auxiliary valve 51 described later.

The seventh flow path 43G connects the injection rod side chamber 29r and the pressure increasing rod side chamber 33r. Thereby, for example, the pressure of the pressure increasing rod side chamber 33r increased by the pressure increasing piston 35 can be applied to the injection rod side chamber 29r, and the pressure of the injection rod side chamber 29r can be increased in advance.

The plurality of channels (43A to 43H, etc.) are composed of, for example, steel pipes, flexible hoses, or metal blocks. A part of the plurality of flow paths may be shared as appropriate. For example, in the example of FIG. 2, the first flow path 43A to the third flow path 43C are partially shared on the accumulator 41 side, and the fourth flow path 43D, the fifth flow path 43E, and the seventh flow path 43G are shared. , A part of the injection rod side chamber 29r side is shared.

The injection valve 45 is provided, for example, in the second flow path 43B (a portion thereof that is not shared with the other flow paths (43A and 43C)), and the hydraulic fluid from the accumulator 41 to the injection head side chamber 29h is provided. Allow or prohibit flow. The injection valve 45 is composed of, for example, a pilot type check valve, and when the pilot pressure is not introduced, the hydraulic fluid flows from the accumulator 41 to the injection head side chamber 29h, and vice versa. Prohibit directional flow and, when pilot pressure is introduced, prohibit both flows. The injection valve 45 also contributes to the prevention of backflow of the hydraulic fluid from the injection head side chamber 29h.

The pressure boosting valve 47 is provided, for example, in the third flow path 43C (a portion of which is not shared with the other flow paths (43A and 43B)), and the hydraulic fluid from the accumulator 41 to the pressure boosting head side chamber 33h. Allow or prohibit the flow of. The pressure boosting valve 47 is composed of, for example, a flow rate control valve. The pressure boosting valve 47 may be one that performs pressure compensation (flow rate adjusting valve) or one that does not perform pressure compensation. Further, the control method of the pressure boosting valve 47 may be, for example, any of a spring type, an electromagnetic type and a pilot type, and a combination of two or more of these. The pressure boosting valve 47 may be a servo valve with feedback control or a proportional valve with open control. FIG. 2 shows a flow rate adjusting valve as a pressure boosting valve 47, which is closed at a normal position by a spring and is opened by sequentially operating an electromagnetic force and a pilot pressure.

The pressure boosting valve 47 may be configured by a non-leak valve having relatively little leakage of the hydraulic fluid in the closed state. It is often stated in the catalog or specifications that the non-leak valve is a non-leak valve, and it is possible to specify whether or not the non-leak valve is a non-leak valve based on the description.

The speed valve 49 is, for example, a flow rate control valve provided in the fourth flow path 43D (a portion of which is not shared with other flow paths (43E and 43G)), and is, for example, a tank from the injection rod side chamber 29r. It contributes to the control of the flow rate of the hydraulic fluid discharged to 37. By controlling this flow rate, the forward speed of the injection piston 31 is controlled. That is, the speed valve 49 constitutes a so-called meter-out circuit. The speed valve 49 may be one that performs pressure compensation (flow rate adjusting valve) or one that does not perform pressure compensation. Further, the control method of the speed valve 49 may be, for example, any of a spring type, an electromagnetic type, a pilot type, and a combination of two or more thereof. The speed valve 49 may be a servo valve with feedback control or a proportional valve with open control. FIG. 2 shows a flow rate adjusting valve as a speed valve 49, which is closed at a normal position by a spring and is opened by sequentially operating an electromagnetic force and a pilot pressure.

Here, in the illustrated example, the seventh flow path 43G connecting the injection rod side chamber 29r and the pressure increasing rod side chamber 33r is not provided with a valve that allows or prohibits the flow of the flow path. Therefore, by opening and closing the speed valve 49, not only the flow from the injection rod side chamber 29r to the tank 37 but also the flow from the pressure increasing rod side chamber 33r to the tank 37 is allowed or prohibited.

The auxiliary valve 51 is composed of, for example, a switching valve having 4 ports and 3 positions, and switches connection and disconnection between the 4 ports. Each port is connected to, for example, a fifth flow path 43E (injection rod side chamber 29r), a sixth flow path 43F (injection head side chamber 29h and a small diameter cylinder portion 33a), a pump 39 or a tank 37. In the illustrated example, the eighth flow path 43H connecting one port of the auxiliary valve 51 and the tank 37 is shared with the portion of the fourth flow path 43D on the downstream side of the speed valve 49. There is.

Further, in the illustrated example, the seventh flow path 43G connecting the injection rod side chamber 29r and the pressure increasing rod side chamber 33r has a part of the fifth flow path 43E and the injection rod side chamber 29r side in common. The port of the auxiliary valve 51 connected to the fifth flow path 43E (injection rod side chamber 29r) is also connected to the seventh flow path 43G (pressure increasing rod side chamber 33r).

The auxiliary valve 51 cuts off the connection of four ports, for example, at a position in the center of the paper (neutral position and / or normal position). In the following, this position may be referred to as a closed position.

Further, the auxiliary valve 51 connects the fifth flow path 43E (injection rod side chamber 29r) and the pump 39 at, for example, the position shown on the left side of the paper surface (hereinafter, may be referred to as “a position”), and is the second valve 51. 6 The flow path 43F (injection head side chamber 29h and small diameter cylinder portion 33a) is connected to the tank 37. Thereby, for example, the hydraulic fluid can be supplied from the pump 39 to the injection rod side chamber 29r to retract the injection piston 31.

Here, in the illustrated example, the seventh flow path 43G connecting the injection rod side chamber 29r and the pressure increasing rod side chamber 33r is not provided with a valve that allows or prohibits the flow of the flow path. Therefore, for example, when the hydraulic fluid is supplied from the pump 39 to the injection rod side chamber 29r via the auxiliary valve 51, the hydraulic fluid is also supplied from the pump 39 to the pressure increasing rod side chamber 33r. As a result, for example, a force for retracting the pressure boosting piston 35 is obtained.

Further, for example, by setting the auxiliary valve 51 to the a position, when the hydraulic fluids of the booster rod side chamber 33r and the injection rod side chamber 29r are compressed by the advancement of the pressure booster piston 35, the injection head side chamber 29h and the small diameter cylinder portion. The pressure of 33a can be released.

Further, the auxiliary valve 51 connects the fifth flow path 43E (injection rod side chamber 29r) and the tank 37 at the position shown on the right side of the paper surface (hereinafter, may be referred to as “b position”), and the sixth flow. The road 43F (injection head side chamber 29h) and the pump 39 are connected. As a result, the hydraulic fluid can be supplied from the pump 39 to the injection head side chamber 29h to advance the injection piston 31. However, in the present embodiment, the flow of this hydraulic fluid is not essential, and the auxiliary valve 51 may be a two-position valve having a closed position and an a position.

The control method of the auxiliary valve 51 may be, for example, a spring type, an electromagnetic type, a pilot type, or a combination of two or more thereof. FIG. 2 shows an auxiliary valve 51 that is set to a closed position (position at the center of the paper surface) at a normal position by a spring and is controlled by sequentially operating an electromagnetic force and a pilot pressure.

The valve 53 is, for example, a check valve provided in the first flow path 43A (a portion of which is not shared with the other flow paths (43B and 43C)), and allows the flow from the pump 39 to the accumulator 41. And prohibit the flow in the opposite direction.

The valve 54 is, for example, a check valve provided in the fourth flow path 43D (of which the portion is shared with the eighth flow path 43H), which allows the flow to the tank 37 and in the opposite direction. Prohibit the flow.

The valve 55 is, for example, a check valve provided in a flow path (reference numeral omitted) connecting the auxiliary valve 51 and the pump 39, and allows the flow from the pump 39 to the auxiliary valve 51, and vice versa. Prohibit directional flow.

In addition to the above, the hydraulic pressure device 28 includes, for example, a filter 57 for filtering the hydraulic fluid from the tank 37 to the pump 39, a cooler 59 for cooling the hydraulic fluid flowing to the tank 37 via the speed valve 49, and the like. ing.

(Functional part of control device and sensor)
The control device 13 is composed of, for example, a computer including a CPU, RAM, ROM, and an external storage device, although not particularly shown. By executing the program stored in the ROM and the external storage device by the CPU, a plurality of functional units responsible for various controls or operations are configured.

As shown in FIG. 2, the plurality of functional units are, for example, a pressurization control unit 13a, an injection control unit 13b, and a pressure increase control unit 13c. The pressurization control unit 13a controls to increase the pressure of the injection rod side chamber 29r before the start of injection. The injection control unit 13b controls (for injection in a narrow sense) for injecting the molding material into the mold 101. The pressure increase control unit 13c controls (for pressure increase) to increase the pressure of the molding material injected into the mold 101.

These functional units output a control signal to the hydraulic pressure device 28 based on signals from, for example, an input device 17 and various sensors. The various sensors are, for example, a position sensor 69 that detects the position of the plunger 23 and a pressure sensor 71 that detects the pressure of the accumulator 41.

The position sensor 69 constitutes, for example, a linear encoder. For example, the position sensor 69 faces the scale portion (not shown) in a direction orthogonal to the axial direction of the scale portion, and generates a pulse according to the relative movement in the axial direction with the scale portion. Then, the position sensor 69 and / or the control device 13 can specify the relative position between the position sensor 69 and the scale unit by integrating the number of generated pulses, and also specify the number of pulses per hour. The speed can be specified by doing so.

The position sensor 69 is fixedly provided to the injection cylinder portion 29, and the scale portion is provided on the injection piston rod 32 or a member fixed to the injection piston rod 32. Therefore, by detecting the position and / or speed of the injection piston rod 32, the position and / or speed of the plunger 23 is indirectly detected.

The position sensor 69 may only output a pulse, or may specify a position and / or a speed and output a signal corresponding to the specified position and / or speed. Even in the former case, it can be said that the signal corresponding to the position is output because the total number of pulses differs depending on the position, and the number of pulses per unit time differs depending on the speed, so the signal according to the speed is output. It can be said that it is outputting. The signal in the latter case is, for example, a signal whose signal level changes according to a change in position and / or speed.

In addition to the linear encoder as described above, the position sensor 69 is fixedly provided to, for example, the injection cylinder portion 29, and measures the distance to the injection piston rod 32 or a member fixed to the injection piston rod 32. It may be a laser length measuring instrument.

The pressure sensor 71 outputs, for example, a signal corresponding to the pressure of the liquid chamber 41e. The pressure-based signal is, for example, a signal whose signal level changes in response to a change in pressure. As the pressure sensor 71, a known appropriate one such as a diaphragm type may be used. Further, as the pressure sensor 71, a pressure sensor 71 that detects the pressure of the gas chamber 41f may be used in addition to or instead of the one that detects the pressure of the liquid chamber 41e.

(Operation of injection device)
FIG. 4 is a timing chart for explaining the operation of the injection device 9.

The upper part of FIG. 4 shows the time course of the injection speed V (advance speed of the plunger 23) and the injection pressure P (pressure applied to the molten metal by the plunger 23). In the upper part of FIG. 4, the horizontal axis shows the time t, and the vertical axis shows the injection speed V and the injection pressure P. The lines LV and LP show changes in the injection speed _V and the injection pressure _P with respect to the passage of time t, respectively.

The lower part of FIG. 4 shows the operation of the injection valve 45, the pressure boosting valve 47, the speed valve 49, and the auxiliary valve 51 corresponding to the passage of time in the upper part of FIG. In the lower part of FIG. 4, the solid line shows the operation in this embodiment, and the two-dot chain line shows a modification described later. The "open" of the boosting valve 47 and the speed valve 49 indicates that these valves are open and the opening degree is appropriately controlled. The timing at which the control device 13 outputs the control signal may be earlier than the timing shown in the figure in consideration of the valve control delay and the like.

As a basic operation, the injection device 9 performs, for example, low-speed injection (generally at time points t0 to t1), high-speed injection (generally at time points t1 to t2), and boosting (boosting, generally at time points t3 to) in order. Further, prior to low-speed injection, the pressure of the injection rod side chamber 29r is increased to prevent jumping (~ t0). The operation of these steps is, for example, as follows.

(Pressurization before the start of injection)
Before the start of pressurization, the injection device 9 is in a state as shown in FIGS. 1, 2 and 3 (a), for example. That is, the injection piston 31 and the pressure boosting piston 35 are located, for example, in the retreat limit. The plunger 23 is located behind the supply port 21a. The accumulator 41 has been filled to a predetermined pressure, for example. As already described, the pump 39 may be driven all the time or only when necessary, and in the latter case, for example, it is stopped. The injection valve 45 is closed by introducing pilot pressure. The pressure boosting valve 47, the speed valve 49, and the auxiliary valve 51 are in the closed position.

Then, when the predetermined pressurization start condition is satisfied, the control device 13 starts pressurization to the injection rod side chamber 29r. Specifically, the control device 13 opens, for example, the pressure boosting valve 47 and sets the auxiliary valve 51 to the a position. As a result, the hydraulic fluid is supplied from the accumulator 41 to the pressure increasing head side chamber 33h, and the small diameter cylinder portion 33a and the injection head side chamber 29h are depressurized. As a result, as shown in FIG. 3B, the pressure boosting piston 35 advances until the forces received from the front and rear are balanced (only the distance δ from another viewpoint), and the pressure boosting rod side chamber 33r and the pressure boosting rod side chamber 33r The hydraulic fluid in the injection rod side chamber 29r communicating with the above is compressed.

The pressure P1 (FIG. 3 (b)) of the injection rod side chamber 29r at this time is theoretically the pressure P0 (FIG. 3 (b)) of the accumulator 41 and the pressure increase ratio S3 related to the injection rod side chamber 29r by the pressure boosting piston 35. The size is multiplied by / S4 (P0 × S3 / S4). The distance δ is determined, for example, by the pressure before pressurization to the injection rod side chamber 29r, the pressure P1, the compressibility of the hydraulic fluid, and the volume of the closed space including the injection rod side chamber 29r. However, when the pump 39 is driven, in the illustrated example, the hydraulic fluid is supplied from the pump 39 to the space including the injection rod side chamber 29r via the auxiliary valve 51 at the a position, so that the pump 39 is driven. The distance δ can be smaller than if it were not.

Since the small diameter cylinder portion 33a and the injection head side chamber 29h are depressurized when the pressure is applied to the injection rod side chamber 29r, the injection piston 31 does not advance even if the pressure boosting piston 35 advances. That is, the plunger 23 does not move forward.

The pressurization start condition (in another viewpoint, the pressurization start time) is such that the compression (pressurization) of the hydraulic fluid in the injection rod side chamber 29r by the pressure boosting piston 35 is completed by the time the injection is started, or the compression is performed. It may be set appropriately so as to proceed to some extent.

The completion of compression or pressurization here means, for example, that the pressure before and after the pressure boosting piston 35 is balanced and the pressure boosting piston 35 stops, and from another viewpoint, the pressure P1 of the injection rod side chamber 29r is the above-mentioned P0 ×. It has reached S3 / S4 (strictly speaking, it is slightly smaller than this due to the influence of sliding resistance and the like), and from another viewpoint, the amount of movement of the pressure boosting piston 35 has reached the distance δ. In the description of the present disclosure, for example, an operation of closing the pressure boosting valve 47 while the pressure of the injection rod side chamber 29r is rising is referred to as a stop or end of pressurization (compression), and is called pressurization (compression). It is not said that the compression) is completed.

Specifically, the pressurization start condition may be, for example, that the mold clamping by the mold clamping device 7 is completed. The completion of mold clamping is detected by, for example, a limit switch. In this case, in general, after the mold clamping is completed, the molten metal is supplied to the sleeve 21 by a hot water supply device (not shown), and the plunger 23 starts to move forward, so that pressurization can be performed during the hot water supply. As described above, the pressurization start condition may be, for example, a precondition for starting injection (mold compaction is completed in the above example), or a predetermined time has elapsed since such a precondition occurs.

(Slow injection)
When the predetermined injection start condition is satisfied (time point t0), the control device 13 ends the pressurization to the injection rod side chamber 29r, starts the advancement of the plunger 23, and further, the relatively low speed injection speed V. Advance the plunger 23 with _L. As a result, the molten metal in the sleeve 21 is pushed out toward the cavity Ca while suppressing the entrainment of air by the molten metal.

Specifically, for example, the control device 13 closes the pressure boosting valve 47 and stops the supply of the hydraulic fluid from the accumulator 41 to the pressure booster head side chamber 33h. As a result, the operation (pressurization) of applying the pressure of the accumulator 41 to the injection rod side chamber 29r via the pressure boosting piston 35 is completed. Further, for example, the control device 13 sets the auxiliary valve 51 in a neutral position, and prohibits the discharge of the hydraulic fluid from the injection head side chamber 29h and the small diameter cylinder portion 33a to the tank 37. This prepares for the start of injection.

Subsequently, for example, the control device 13 supplies the hydraulic fluid from the accumulator 41 to the injection head side chamber 29h by stopping the introduction of the closing pilot pressure into the injection valve 45. Further, the control device 13 opens, for example, the speed valve 49 at an appropriate opening degree to allow the hydraulic fluid to be discharged from the injection rod side chamber 29r to the tank 37. As a result, the injection piston 31 advances, and eventually the plunger 23 advances.

At this time, as already described, the pressure of the injection rod side chamber 29r is increased in advance, so that jumping is suppressed. For example, theoretically, if the area ratio S3 / S4 is the area ratio S1 / S2 or more, the plunger 23 does not move forward (jumping does not occur).

The pressure boosting piston 35 is urged rearward by supplying the hydraulic fluid from the accumulator 41 to the injection head side chamber 29h. However, the pressure boosting valve 47 is closed, and the discharge of the hydraulic fluid in the pressure booster head side chamber 33h is prohibited. Therefore, as shown in FIG. 3C, the pressure boosting piston 35 does not retreat, but the position advanced from the retreat limit at a distance δ is maintained. As a result, for example, the volume of the small-diameter cylinder portion 33a becomes large due to the retreat of the pressure boosting piston 35, and there is a possibility that the advance of the plunger 23 is delayed with respect to the supply of the hydraulic fluid to the injection head side chamber 29h. Will be done. Since the pressure boosting valve 47 is a non-leak valve, the effect of holding the position of the pressure boosting piston 35 is increased.

The injection start condition may be, for example, that the hot water supply to the sleeve 21 by the hot water supply device (not shown) is completed when the pressurization start condition is the mold clamping completion as described above. From another point of view, the injection start condition satisfies all the preconditions for injection start (for example, mold clamping completion and hot water supply completion) in a general injection device that does not pressurize the injection rod side chamber 29r before the injection start. That is.

The injection start condition may include that the pressurization to the injection rod side chamber 29r before the injection start is completed in addition to the above-mentioned preconditions being satisfied. The completion of pressurization may be determined, for example, by whether or not a predetermined time has elapsed from the start of pressurization, or the injection rod side chamber 29r (pressure increasing rod side chamber 33r and the seventh flow) detected by a pressure sensor (not shown). It may be determined by whether or not the pressure of the road 43G) has reached a predetermined threshold value. In addition, for example, the determination can be made by detecting the movement or position of the pressure boosting piston 35.

In the above example, the pressurization start condition does not include the final precondition for the start of injection (for example, the completion of hot water supply), which does not apply pressurization to the injection rod concubine 29r before the start of injection, and the injection starts. It is set to be satisfied before the condition. From another point of view, the pressurization start condition is set so that there is no delay in the start of injection or the delay is reduced as compared with general injection without pressurization. However, the pressurization start condition may include the final precondition for the start of injection, and the injection start condition may be, for example, the completion of pressurization.

In the illustrated example, the injection valve 45 and the speed valve 49 are opened substantially at the same time when the pressure boosting valve 47 and the auxiliary valve 51 are closed. However, even if the pressure boosting valve 47 and the auxiliary valve 51 are closed, the pressure in the injection rod side chamber 29r is theoretically maintained (without considering liquid leakage), so that the pressure boosting valve 47 and / or the auxiliary valve 47 and / or the auxiliary valve are maintained. There may be a time lag between the operation of closing the valve 51 and the operation of opening the injection valve 45 and the speed valve 49. In other words, the pressurization to the injection rod side chamber 29r before the start of injection does not have to be continued until the injection start condition is satisfied (until the start of injection). However, if the pressurization is continued until the start of the pressurization, for example, it is easy to secure the time required to complete the pressurization before the start of the pressurization (from another viewpoint, the pressurization start time is delayed), and the pressurization is facilitated. , The effect of pressurization due to liquid leakage does not decrease.

Further, in the illustrated example, the injection valve 45 and the speed valve 49 are opened substantially at the same time, but the speed valve 49 may be opened after the injection valve 45 is opened. In this case, for example, when the speed valve 49 is opened, the plunger 23 starts to move forward. That is, the injection start is when the speed valve 49 is opened.

The speed of the plunger 23 is controlled, for example, by controlling the opening degree of the speed valve 49. This speed control may be open control or feedback control based on the speed detected by the position sensor 69. The speed feedback control may be like finding the deviation of the speed itself, or finds the deviation between the momentary (every elapsed time) target position obtained from the speed target value and the detected position. , The speed feedback control may be substantially performed by performing the position feedback control from moment to moment.

The low-speed injection speed _VL may be appropriately set, but is, for example, less than 3 m / s. The low-speed injection speed _VL is, for example, a constant value. However, appropriate shift control may be performed. In low-speed injection, the injection pressure is relatively low because the injection speed is relatively low.

(High-speed injection)
When the plunger 23 reaches a predetermined high-speed switching position (time point t1), the control device 13 advances the plunger 23 at a relatively high high-speed injection speed _VH . As a result, for example, the molten metal is quickly filled in the cavity Ca without delaying the solidification of the molten metal. The high-speed injection speed _VH may be appropriately set, but is, for example, 3 m / s or more. The high-speed injection speed V _H is, for example, a constant value. However, appropriate shift control may be performed. In high-speed injection, the injection pressure is higher than the pressure at the time of low-speed injection because the injection speed is relatively high.

For the above operation, specifically, the control device 13 opens the speed valve 49 while continuing to supply the hydraulic fluid from the accumulator 41 to the injection head concubine 29h, for example, from the low speed injection. Increase the degree. When only increasing the opening degree of the speed valve 49 in this way, the control device 13 performs, for example, open control or feedback control continuously from the low speed injection, and simply sets the target value of the speed from the low speed injection to the high speed injection. All you have to do is change it to something.

For example, the control device 13 converts the target speed set for each section in which the movement range of the plunger 23 is divided into a plurality of sections into the target value of the position of the plunger 23 for each elapsed time, and the position feedback control (substantially) every moment. Speed feedback control) is performed, and it is not detected whether or not the plunger 23 has reached the high-speed switching position. However, the control device 13 may detect that the plunger 23 has reached a predetermined high-speed switching position based on the signal from the position sensor 69 and switch the target value of the speed.

(Deceleration)
As a result of high-speed injection, when the cavity Ca is substantially filled with the molten metal (time point t2), the pressure of the molten metal increases, which causes the plunger 23 to decelerate. The deceleration control may be performed by reducing the opening degree of the speed valve 49 at an appropriate time. As a result of the deceleration, the plunger 23 is almost stopped (time point t4).

(Pressure increase and pressure retention)
The control device 13 starts increasing the pressure while the speed of the plunger 23 is decelerated as described above. Specifically, for example, the control device 13 opens the pressure boosting valve 47 at an appropriate time (t3), and supplies the hydraulic fluid from the accumulator 41 to the pressure boosting head concubine 33h. On the other hand, the pressure boosting rod side chamber 33r is allowed to discharge the hydraulic fluid to the tank 37 via the speed valve 49. Therefore, the pressure boosting piston 35 applies a pressure higher than the pressure of the booster head side chamber 33h to the injection head side chamber 29h, and eventually the pressure is boosted. The injection valve 45 closes by itself when the pressure in the injection head side chamber 29h becomes higher than the pressure in the accumulator 41. However, the injection valve 45 may be closed by introducing a pilot pressure that closes at an appropriate time. Further, the control device 13 sets the opening degree of the speed valve 49 to an appropriate opening degree for boosting so that an appropriate boosting curve can be obtained.

The pressure of the pressure boosting head side chamber 33h rises when the pressure is applied to the injection rod side chamber 29r before the start of injection, and then is relatively high (for example, higher than the tank pressure) so as to suppress the retreat of the pressure boosting piston 35. ) It is maintained. Therefore, the pressurization to the injection rod side chamber 29r of the present embodiment also has a secondary effect of reducing the time delay from the opening of the pressure boosting valve 47 to the rise of the pressure in the pressure boosting head side chamber 33h. become.

Even if the two are deviated from each other, for example, the output timing of the control command for opening the pressure boosting valve 47 is delayed with respect to the output timing of the control command for opening the pressure boosting valve 49. good. Further, the output of the control command for opening the pressure boosting valve 47 can be started during high-speed injection.

After that, the force due to the increased pressure of the injection head side chamber 29h and the force due to the pressure received by the plunger 23 from the molten metal are balanced, so that the injection pressure becomes constant (the casting pressure becomes). At this time, the pressure of the injection rod side chamber 29r is, for example, a tank pressure (generally 0). It should be noted that the discharge of the hydraulic fluid from the injection rod side chamber 29r is prohibited by closing the speed valve 49 at an appropriate time, and the pressure of the injection rod side chamber 29r is set to an appropriate pressure higher than the tank pressure. Casting pressure may be obtained. In the pressure holding step, the control device 13 maintains the state when the casting pressure is obtained. For example, the boost valve 47 and the speed valve 49 are left open.

(Plunger retreat, etc.)
When the molten metal filled in the cavity Ca solidifies, the control device 13 ends the holding pressure. Specifically, for example, the control device 13 closes the pressure boosting valve 47 and the speed valve 49. Further, as already described, the control device 13 performs mold opening by the mold clamping device 7 and extrusion by the extrusion device 11. Although not particularly shown, the control device 13 may control the hydraulic pressure device 28 so as to push the biscuit by the plunger 23 (to perform extrusion follow-up) at the time of mold opening.

After the start of mold opening, or when extrusion follow-up is performed, the control device 13 returns the injection device 9 to the initial state before the start of injection. Specifically, for example, in the injection device 9, the auxiliary valve 51 is set to the a position. That is, the pump 39 is connected to the injection rod side chamber 29r and the pressure increasing rod side chamber 33r, and the injection head side chamber 29h and the tank 37 are connected to each other. Further, the control device 13 also connects the pressure boosting head side chamber 33h to the tank 37 via a flow path and a valve (not shown). Further, the control device 13 continues or starts driving the pump 39. As a result, the hydraulic fluid is supplied from the pump 39 to the injection rod side chamber 29r and the pressure boosting rod side chamber 33r, and the injection piston 31 and the pressure boosting piston 35 retract. The hydraulic fluid in the injection head side chamber 29h and the pressure increasing head side chamber 33h is discharged to the tank 37. The hydraulic fluid discharged from the injection head side chamber 29h and / or the pressure boosting head side chamber 33h may be filled in the accumulator 41 instead of the tank 37.

Although not particularly shown, after the injection piston 31 and the pressure boosting piston 35 reach the retreat limit, the control device 13 puts the auxiliary valve 51 in the neutral position, and in the embodiment where the pump 39 is not continuously driven, the pump 39 To stop. That is, the supply of the hydraulic fluid to the injection rod side chamber 29r and the pressure increasing rod side chamber 33r by the pump 39 is stopped.

After the retreat of the plunger 23 is completed, the control device 13 drives the pump 39 with the injection valve 45, the pressure boosting valve 47, and the auxiliary valve 51 closed. As a result, the hydraulic fluid is supplied from the pump 39 to the accumulator 41, and the accumulator 41 is filled. Then, when the pressure detected by the pressure sensor 71 reaches a predetermined set pressure, the control device 13 stops driving the pump 39, for example.

(First modification)
Although not particularly shown, the hydraulic pressure device 28 is modified so that the hydraulic fluid can be discharged from the injection rod side chamber 29r to the tank 37 via the speed valve 49 while supplying the hydraulic fluid from the pump 39 to the injection head side chamber 29h. May be good. For example, the auxiliary valve 51 is connected to the pump 39 and the sixth flow path 43F (injection head side chamber 29h) at the b position, and shuts off the fifth flow path 43E (injection rod side chamber 29r) and the tank 37. Configure to.

Then, in low-speed injection, the auxiliary valve 51 is set to the b position (see the two-dot chain line in the diagram relating to the auxiliary valve 51 in FIG. 4), and the hydraulic fluid is supplied from the pump 39 to the injection head concubine 29h to supply the injection piston. 31 is advanced, and the speed of the plunger 23 of the injection rod side chamber 29r is controlled by the speed valve 49. Further, the injection valve 45 is opened at the start of high-speed injection (see the two-dot chain line related to the injection valve 45 in FIG. 4).

Even when the hydraulic fluid is supplied from the pump 39 to the injection head side chamber 29h in this way, jumping is suppressed by compressing the hydraulic fluid in the injection rod side chamber 29r in advance by the pressure boosting piston 35.

(Second modification)
In the embodiment, the pressure boosting valve 47 is closed in low speed injection and high speed injection (in a narrow sense). However, as shown by the two-dot chain line in the diagram relating to the pressure boosting valve 47 in FIG. 4, the opening degree of the pressure boosting valve 47 is narrowed in the injection in a narrow sense, and a small amount of hydraulic fluid is applied from the accumulator 41 to the pressure boosting head concubine 33h. May be supplied. Thereby, for example, even if the hydraulic fluid in the pressure increasing head side chamber 33h leaks, the retreat of the pressure increasing piston 35 can be suppressed.

(Third modification example)
After filling the accumulator 41 and before the pressurization valve 47 is opened to pressurize the injection rod side chamber 29r, the auxiliary valve 51 is set to the a position (to the auxiliary valve 51 in FIG. 4). (Refer to the two-dot chain line in the diagram), hydraulic pressure may be applied from the pump 39 to the injection rod side chamber 29r and the pressure increasing rod side chamber 33r. In this case, for example, the pressure in the injection rod side chamber 29r can be increased immediately before pressurization is performed by the pressure boosting piston 35, and / or after the injection piston 31 and the pressure boosting piston 35 in the previous cycle are retracted. The pressure in the injection rod side chamber 29r, which has dropped due to liquid leakage or the like, can be recovered immediately before the pressurization by the boosting piston 35. As a result, for example, the movement amount δ of the pressure boosting piston 35 can be shortened.

As described above, in the present embodiment, the injection device 9 is an injection cylinder 27 that drives a plunger 23 that pushes the molding material into the front mold 101, and a hydraulic pressure device 28 that controls the flow of the hydraulic fluid in the injection cylinder 27. And a control device 13 for controlling the hydraulic pressure device 28. In the injection cylinder 27, the injection piston rod 32 is connected to the rear part of the plunger 23. The injection piston 31 is fixed to the rear portion of the injection piston rod 32. The injection cylinder portion 29 slidably accommodates the injection piston 31, and the inside is divided into a front injection rod side chamber 29r and a rear injection head side chamber 29h by the injection piston 31. The small-diameter cylinder portion 33a communicates with the injection head side chamber 29h. The large-diameter cylinder portion 33b is connected in series with the small-diameter cylinder portion 33a, and has a larger diameter than the small-diameter cylinder portion 33a. The small-diameter piston 35a is slidably housed in the small-diameter cylinder portion 33a. The large-diameter piston 35b is fixed in series with the small-diameter piston 35a and is slidably housed in the large-diameter cylinder portion 33b. And the pressure increasing head side chamber 33h on the opposite side. The control device 13 controls the hydraulic pressure device 28 to supply the hydraulic fluid to the pressure boosting head side chamber 33h and apply the hydraulic pressure from the pressure boosting rod side chamber 33r to the injection rod side chamber 29r before the start of injection. It has a portion 13a.

Therefore, for example, as described above, it is possible to reduce the possibility of jumping at the start of injection. At this time, due to the pressure increasing action of the pressure increasing piston 35, a pressure higher than the pressure applied to the pressure increasing head side chamber 33h can be applied to the injection rod side chamber 29r. Further, for example, since the pressure boosting action is obtained by using the pressure boosting piston 35, it is not necessary to provide a pressure boosting cylinder separately from the injection cylinder 27, and the injection device 9 is compared with such an embodiment. Miniaturization and / or cost reduction. The pressure increase of the pressure increasing rod side chamber 33r by the pressure increasing piston 35 in the pressurization (to t0) to the injection rod side chamber 29r is different from the pressure increase in the small diameter cylinder portion 33a by the pressure increasing piston 35 in the pressure increasing (t3 to). It is not directly linked to the pressurization of the injection head side chamber 29h. Therefore, for example, it is possible to suppress the advance of the injection piston 31 while advancing the pressure boosting piston 35. The pressure-increasing action on the pressure-increasing rod side chamber 33r of the pressure-increasing piston 35 is different from the pressure-increasing action on the inside of the small-diameter cylinder portion 33a by the pressure-increasing piston 35 in the pressure-increasing (t3 ~), and is not a normally used action. The configuration of the present embodiment in which the above-mentioned various effects can be obtained by utilizing such a pressure increasing action is epoch-making.

In the present embodiment, the pressurization control unit 13a controls the hydraulic pressure device 28 so as to release the pressure of the injection head side chamber 29h when the pressure is applied to the injection rod side chamber 29r before the start of injection.

Therefore, it is possible to reliably suppress the possibility that the injection piston 31 will move forward when pressurization is applied. As a result, for example, the relative relationship between the position and the speed of the plunger 23 at the start of injection, which is set by the operator, can be realized with high accuracy.

In the present embodiment, the injection cylinder 27 has a stopper 36 fixed to the injection cylinder portion 29 to regulate the retreat of the injection piston 31.

Therefore, even if the pressure of the injection rod side chamber 29r rises before the start of injection, the retreat of the injection piston 31 is suppressed. Unlike the mode in which the rod fixedly provided on the pressure boosting piston 35 is brought into contact with the rear end of the injection piston 31 to regulate the retreat of the injection piston 31, the advance of the pressure boosting piston 35 before the start of injection is , It is not directly connected to the advance of the injection piston 31.

In the present embodiment, the small diameter cylinder portion 33a continues in series with respect to the rear side of the injection cylinder portion 29. The inner diameter of the small diameter cylinder portion 33a is smaller than the inner diameter of the injection cylinder portion 29, and the stopper 36 is configured by the step between the injection cylinder portion 29 and the small diameter cylinder portion 33a.

Therefore, for example, it is not necessary to form the stopper 36 separately from the change in the inner diameter of the entire cylinder portion (29 and 33). As a result, for example, it is easy to reduce the number of members constituting the entire cylinder portion and reduce the manufacturing cost of the cylinder portion.

In the present embodiment, the pressure received by the pressure increasing head side chamber 33h of the large diameter piston 35b with respect to the ratio S1 / S2 of the pressure receiving area S1 in the injection head side chamber 29h of the injection piston 31 to the pressure receiving area S2 in the injection rod side chamber 29r of the injection piston 31. The ratio (S3 / S4) / (S1 / S2) of the ratio S3 / S4 to the pressure receiving area S4 in the pressure increasing rod side chamber 33r of the large-diameter piston 35b of the area S3 is 0.9 or more and 1.2 or less.

Therefore, for example, when the pressure before the start of injection generated in the injection rod side chamber 29r by the pressure increasing action of the pressure boosting piston 35 is supplied from the accumulator 41 to the injection head side chamber 29h for the start of injection, the injection piston 31 It is easy to make the pressure equal to or higher than the pressure generated in the injection rod side chamber 29r by the pressure increasing action. As a result, for example, jumping is more reliably suppressed. When (S3 / S4) / (S1 / S2) is 1.1 or more, for example, the pressure of the injection rod side chamber 29r before the start of injection is static pressure, and the injection head to which the hydraulic fluid is supplied for injection. Since the pressure in the side chamber 29h is a dynamic pressure, it is easy to reduce the possibility that the plunger 23 moves forward. On the other hand, if (S3 / S4) / (S1 / S2) is large, the pressure-increasing action of the pressure-increasing piston 35 on the injection head side chamber 29h in the pressure increase (t3 ~) is reduced, but it is 1.2 or less. If so, such a risk is reduced.

In the first embodiment, the die casting machine 1 is an example of a molding machine, and the speed valve 49 is an example of a flow rate control valve.

<Second Embodiment>
(Structure of injection drive unit)
FIG. 5 is a schematic view showing the configuration of the injection device 209 according to the second embodiment of the present disclosure.

The injection drive unit 25 of the first embodiment was a hydraulic type. On the other hand, the injection drive unit 225 of the present embodiment is a so-called hybrid type in which a hydraulic type and an electric type are combined. Further, in response to this difference, the operation of the injection drive unit 225 (control by the control device 13) of the present embodiment is also different from that of the first embodiment. The other configurations of this embodiment are the same as those of the first embodiment.

Specifically, the injection drive unit 225 has an electric drive unit 281 in addition to the injection cylinder 27 similar to that of the first embodiment.

Although omitted in the description of the first embodiment, the rear end of the plunger 23 and the tip of the injection piston rod 32 are connected by, for example, a coupling 24. The coupling 24 has, for example, a case member (reference numeral omitted) for accommodating the rear end of the plunger 23 and the tip of the injection piston rod 32, and the case member is placed between the plunger 23 and the injection piston rod 32. On the other hand, it constitutes a part that expands in diameter.

The electric drive unit 281 includes, for example, a rotary drive motor 283, a transmission mechanism 285 that transmits the rotation of the drive motor 283, and a conversion mechanism 287 that converts the rotation transmitted from the transmission mechanism 285 into translational motion. The driven portion 291 is driven in the moving direction of the plunger 23 by the driving force from the conversion mechanism 287. Then, the plunger 23 is driven by transmitting the driving force from the driven unit 291 to the plunger 23.

The drive motor 283 has, for example, as is not shown, a stator that constitutes one of the armature or the field, and a rotor that constitutes the other of the armature or the field. The arrangement position and orientation of the drive motor 283 may be appropriately set. In the illustrated example, the drive motor 283 is arranged so that the output shaft 283a is parallel to the injection piston rod 32.

The drive motor 283 may be a DC motor, an AC motor, an induction motor, or a synchronous motor. The drive motor 283 may be a motor with a brake. The drive motor 283 is configured as, for example, a servomotor, and constitutes a servo mechanism together with an encoder 283b that detects the rotation of the drive motor 283 and a servo driver (not shown) that supplies power to the drive motor 283. There is.

The transmission mechanism 285 is composed of, for example, a pulley / belt mechanism, and has a first pulley 285a fixed to the output shaft 283a of the drive motor 283, a second pulley 285b fixed to the conversion mechanism 287, and a first one. It has a belt 285c bridged to a pulley 285a and a second pulley 285b. Therefore, when the drive motor 283 is rotated, the rotation is transmitted to the conversion mechanism 287 via the transmission mechanism 285.

The conversion mechanism 287 is composed of, for example, a ball screw mechanism, and has a screw shaft 287a and a nut 287b screwed to the screw shaft 287a via a ball (not shown).

The screw shaft 287a is arranged in parallel with the injection piston rod 32. Further, the screw shaft 287a is restricted from moving in the axial direction and is allowed to rotate around the shaft. On the other hand, the nut 287b is allowed to move in the axial direction and is restricted from rotating around the axis. Therefore, when the screw shaft 287a is rotated, the nut 287b moves in a direction parallel to the injection piston rod 32.

The above-mentioned second pulley 285b is fixed concentrically or coaxially with the screw shaft 287a. Therefore, the rotation transmitted from the drive motor 283 via the transmission mechanism 285 is transmitted to the screw shaft 287a. As a result, the nut 287b moves in the direction parallel to the injection piston rod 32 by the driving force of the driving motor 283.

The driven portion 291 is restricted from being relatively advanced with respect to the injection piston rod 32 by engagement and / or attachment / detachment, and is allowed to be relatively retracted with respect to the injection piston rod 32. Since the injection piston rod 32 and the plunger 23 are connected to each other, the regulation of relative advancement and the allowance of retreat with respect to the injection piston rod 32 referred to here are the regulation of relative advancement with respect to the plunger 23 and the allowance of retreat. Is synonymous with.

Specifically, for example, the driven portion 291 has a base portion 291a, a hook 291b swingably supported by the base portion 291a, and an actuator (not shown) for driving the hook 291b.

The base 291a is fixed to, for example, the nut 287b. Further, the base portion 291a can be brought into contact with the coupling 24 (contacted portion) from behind, for example. Therefore, the contact of the base portion 291a with respect to the coupling 24 restricts the relative advancement with respect to the injection piston rod 32, and allows the base portion 291a to retreat with respect to the injection piston rod 32 rearward from the contact position.

Therefore, the plunger 23 can be advanced by advancing the base portion 291a in a state where the base portion 291a is in contact with the coupling 24. That is, the plunger 23 can be advanced by the driving force of the driving motor 283. Further, the plunger 23 can be advanced relative to the base 291a by supplying the hydraulic fluid to the injection head side chamber 29h and moving the injection piston rod 32 at a relatively high speed.

The hook 291b is formed, for example, in a substantially L shape, and one end thereof is rotatably supported by the base portion 291a. The hook 291b is at a position where the plunger 23 can be engaged with the coupling 24 (contacted portion, engaged portion) in the retracting direction (position shown in the figure) and a position where the engagement is released (the position shown in the figure). It is possible to move from the position shown in the figure to the position moved downward on the paper. The hook 291b can hold the coupling 24 with the base portion 291a at the engaging position.

By engaging the hook 291b, the relative advance of the plunger 23 with respect to the driven portion 291 is restricted. Therefore, for example, deceleration control can be performed while the plunger 23 is being advanced by the electric drive unit 281, and the plunger 23 can be retracted after injection by the electric drive unit 281.

The actuator (not shown) for driving the hook 291b may be realized by an appropriate actuator such as an air cylinder or a linear motor. The hook 291b and the actuator may not be provided. Further, in addition to or instead of engaging the base portion 291a, the driven portion 291 is attached / detached to / from the injection piston rod 32 by, for example, an electromagnet, or is attached / detached by holding (and thus frictional resistance) the injection piston rod 32 in the radial direction. It may be done.

Although not particularly shown, the injection drive unit 225 may have a pair of electric drive units 281 symmetrically or vertically symmetrically. Further, the pair of electric drive units 281 may share one drive electric motor 283. The transmission mechanism 285 may be omitted and the rotation of the drive motor 283 may be directly transmitted to the conversion mechanism 287. Further, contrary to the illustrated example, the nut 287b is made non-movable in the axial direction and rotatable around the axis, and the screw shaft 287a is movable in the axial direction and is not rotatable around the axis, and the driven portion is driven. 291 may be fixed to the screw shaft 287a and the rotation of the drive motor 283 may be transmitted to the nut 287b.

(Structure of hydraulic system)
FIG. 6 is a diagram corresponding to FIG. 2, which schematically shows the configuration of the hydraulic system of the injection drive unit 225.

The hydraulic system of the injection drive unit 225 is different from the hydraulic system of the injection drive unit 25 of the first embodiment only in that, for example, the ninth flow path 243I and the relief valve 293 are provided.

The ninth flow path 243I connects the injection rod side chamber 29r and the tank 37. A part of the ninth flow path 243I on the injection rod side chamber 29r side is shared with a part of other flow paths (43D, 43E and 43G). A part of the ninth flow path 243I on the tank 37 side is shared with a part of the other flow paths (43D and 43H).

The relief valve 293 is provided in the ninth flow path 243I (a portion that is not shared with other flow paths (43D, 43E, 43G and 43H)). The relief valve 293 allows the flow of the hydraulic fluid from the injection rod side chamber 29r to the tank 37 when the pressure of the injection rod side chamber 29r exceeds a predetermined set pressure. As a result, the pressure of the injection rod side chamber 29r is maintained below a predetermined set pressure. In the relief valve 293, the pressure of the injection rod side chamber 29r may act directly on the valve body, or the pressure of the injection rod side chamber 29r may be used as the pilot pressure. Further, the relief valve 293 may be one in which the set pressure is manually adjusted, or one in which the set pressure is adjusted by a solenoid or the like.

The set pressure of the relief valve 293 may be appropriately set. For example, when it is assumed that the hydraulic fluid is supplied from the accumulator 41 to the injection head side chamber 29h and the flow rate of the hydraulic fluid discharged from the injection rod side chamber 29r via the speed valve 49 is the flow rate for high-speed injection. It may be about the same as the pressure generated in the rod side chamber 29r. Further, the pressure may be higher than this, or the pressure may be lower than this.

(Control system configuration)
Similar to the first embodiment, in the control device 13, various functional units are configured by the CPU executing the program. Specifically, for example, as in the first embodiment, the pressurization control unit 13a, the injection control unit 13b, and the pressure increase control unit 13c are constructed. More specifically, the signal input to each functional unit, the calculation of each functional unit, and the output destination of the control signal of each functional unit are different from those of the first embodiment, but are the same as those of the first embodiment for convenience. The code of is attached to each functional part.

As a device for inputting a signal to the control device 13, a device different from the first embodiment is, for example, an encoder 283b. Further, as a device for outputting a signal from the control device 13, what is different from the first embodiment is, for example, an actuator (the driver) (not shown) for driving the driving motor 283 (the driver thereof) and the hook 291b.

(Operation of injection device)
FIG. 7 is a timing chart for explaining the operation of the injection device 209, and is a diagram corresponding to FIG. 4 of the first embodiment.

The horizontal axis, the vertical axis, and the like in FIG. 7 are the same as those in FIG. However, in FIG. 7, a drive motor 283 is added in addition to the control target shown in FIG.

The injection device 209 is, for example, similarly to the first embodiment, pressurization to the injection rod side chamber 29r (to time point t0), low speed injection (generally time point t0 to t1), high speed injection (generally time point t1 to t2), and Pressurization (pressurization, approximately time point t3 ~) is performed in order. Specifically, it is as follows.

(Pressurization before the start of injection)
Before the start of pressurization, the state of the hydraulic system of the injection device 209 is, for example, the same as the state before the start of pressurization of the first embodiment. Further, before the start of pressurization, the base portion 291a of the electric drive unit 281 is engaged with the injection piston rod 32 located at the retracting limit from the rear, and the hook 291b is in the engaging position. ..

Then, the control device 13 pressurizes the injection rod side chamber 29r as in the first embodiment. However, in the present embodiment, since the relief valve 293 is provided, the pressure of the injection rod side chamber 29r does not exceed the set pressure of the relief valve 293. The electric drive unit 281 may contribute to suppressing the advance of the injection piston 31 by its inertia, position control, brake (when equipped with a brake), or the like.

(Slow injection)
Similar to the first embodiment, when the injection start condition is satisfied (time point t0), the control device 13 ends the pressurization to the injection rod side chamber 29r and starts low-speed injection. However, unlike the first embodiment, the low-speed injection is performed by the driving force of the electric driving unit 281.

Specifically, the control device 13 outputs a control signal to the driver of the drive motor 283 to drive the drive motor 283. The driving force of the driving motor 283 is transmitted to the coupling 24 via the transmission mechanism 285, the conversion mechanism 287, and the driven portion 291. As a result, the plunger 23 and the injection piston rod 32 move forward.

At this time, the hydraulic fluid of the injection rod side chamber 29r whose volume decreases as the injection piston 31 advances is discharged to the tank 37 via the relief valve 293. By the action of the relief valve 293, the pressure of the injection rod side chamber 29r is basically maintained at the set pressure. Unlike the first embodiment, the injection valve 45 and the speed valve 49 are maintained in a closed state in the low speed injection.

The hydraulic fluid may be appropriately replenished to the injection head side chamber 29h whose volume increases as the injection piston 31 advances. For example, the injection head side chamber 29h and the tank 37 may be connected (for example, the pump 39 is stopped) with the auxiliary valve 51 at the a position, and the hydraulic fluid may be replenished by a negative pressure. Further, for example, the hydraulic fluid may be supplied from the pump 39 to the injection head side chamber 29h by the configuration as described in the first modification. At this time, the pressure of the hydraulic fluid in the injection head side chamber 29h may be set to such an extent that no negative pressure is generated, or may be set to a pressure equal to or higher than the tank pressure, and the pump 39 may assist the electric drive unit 281.

The speed of the plunger 23 is controlled by adjusting the rotation speed of the drive motor 283. Specifically, the control device 13 feedback-controls the rotation speed of the drive motor 283 based on the signal from the position sensor 69. It should be noted that this speed feedback control may be the one in which the speed itself is a deviation, or may be the position feedback control from moment to moment, as in the first embodiment.

In low speed injection, the hook 291b may or may not be engaged with the coupling 24. In the case of engagement, for example, when multi-stage control including deceleration is performed, it is possible to reduce the possibility that the plunger 23 moves forward away from the base portion 291a due to inertial force.

(High-speed injection)
The high-speed injection is performed in the same manner as in the first embodiment. That is, the injection valve 45 is opened to supply the hydraulic fluid from the accumulator 41 to the injection head side chamber 29h, and the speed valve 49 is opened to allow the hydraulic fluid to be discharged from the injection rod side chamber 29r to the tank 37. To. The speed of the plunger 23 is controlled by the flow rate in the speed valve 49, and is also feedback controlled based on the signal from the position sensor 69.

The discharge of the hydraulic fluid from the relief valve 293 is prohibited by increasing the set pressure or by closing the valve (not shown) provided in the ninth flow path 243I.

In high-speed injection, the hook 291b is set to the position where the engagement is released. Therefore, the plunger 23 driven by the injection cylinder 27 moves forward leaving the driven portion 291 behind. As a result, the electric drive unit 281 does not become a load that hinders the advancement of the plunger 23.

Note that FIG. 7 illustrates a case where the drive of the electric drive unit 281 is stopped in high-speed injection. However, for example, the electric drive unit 281 may retract the driven unit 291 at an appropriate time after the low-speed injection to prepare for the next injection, and as will be understood from the following explanation, the low-speed injection may be performed. Subsequently, the driven unit 291 may be advanced.

(Deceleration, pressure increase, pressure retention, extrusion follow-up and plunger retreat)
Deceleration, pressure increase, pressure retention, extrusion follow-up, and plunger retreat may be performed in the same manner as in the first embodiment. However, following the low-speed injection, the driven unit 291 is advanced, the driven unit 291 is made to catch up with the plunger 23 decelerated by the force from the molten metal, and the electric drive unit 281 is increased in pressure, held in pressure, and followed by extrusion. You may contribute to either. Further, the hook 291b may be engaged with the coupling 24, and the plunger 23 may be retracted by the driving force of the electric drive unit 281.

As described above, in the present embodiment, the speed control in the low speed injection (at the start of the injection from another viewpoint) is performed by the electric drive unit 281. The speed control by the electric motor is more accurate than the control of the hydraulic device, and the speed valve 49 can be fully opened when the speed is controlled by the electric motor. Therefore, the possibility of jumping is low as compared with the first embodiment. Then, by pressurizing the injection rod side chamber 29r before the start of injection, jumping can be suppressed more reliably.

Further, when the injection piston 31 is advanced by the driving force of the electric drive unit 281 in low-speed injection, the hydraulic fluid in the injection rod side chamber 29r is maintained below the set pressure of the relief valve 293. If the pressure applied to the injection rod side chamber 29r before the start of injection is equal to or higher than the set pressure of the relief valve 293, the pressure of the injection rod side chamber 29r is basically constant (set pressure) after the start of low-speed injection. Further, even if the pressure applied to the injection rod side chamber 29r before the start of injection is smaller than the set pressure, the pressure of the injection rod side chamber 29r increases with the progress of low-speed injection and converges to a constant pressure (set pressure).

Therefore, the pressure fluctuation of the injection rod side chamber 29r is suppressed while the plunger 23 is driven by the electric drive unit 281 by the pressurization and the relief valve 293 before the start of injection. As a result, the influence of the pressure fluctuation in the injection cylinder 27 on the control of the electric drive unit 281 is reduced, and more accurate control becomes possible.

Further, in the present embodiment, since a relatively high hydraulic pressure is applied to the injection head side chamber 29h at the start of high-speed injection, jumping may occur at this time. However, since the pressure of the injection rod side chamber 29r is maintained at the set pressure of the relief valve 293 in the low speed injection, the jumping is performed as compared with the embodiment in which the pressure of the injection rod side chamber 29r is the tank pressure in the low speed injection. The risk of occurrence is reduced.

In addition, also in this embodiment, the 2nd modification and the 3rd modification may be applied.

<Third Embodiment>
(Structure of injection drive unit)
FIG. 9 is a schematic view showing the configuration of the injection device 409 according to the third embodiment of the present disclosure. In this figure, the tanks 37 are shown at two positions for convenience, but in reality, the number of tanks 37 may be one.

In the first and second embodiments, the pressure boosting valve 47 is basically opened only when the pressure boosting piston 35 is driven (in other words, only when the pressure is applied to and boosted the injection rod side chamber 29r). Hydraulic pressure was applied from the accumulator 41 to the pressure increasing head side chamber 33h. On the other hand, in the present embodiment, the hydraulic pressure is continuously applied from the accumulator 41 to the pressure increasing head side chamber 33h even when the pressure increasing piston 35 is not driven. Then, by controlling the discharge of the hydraulic fluid from the pressure boosting rod side chamber 33r, the drive of the pressure boosting piston 35 is controlled (pressurization and pressure boosting are performed). Specifically, it is as follows.

The injection drive unit 425 of the injection device 409 may be a hydraulic type as in the first embodiment, or may be a hybrid type as in the second embodiment. In the following, a hydraulic mode will be taken as an example.

In the hydraulic device 428 of the injection drive unit 425, the components different from the hydraulic device 28 of the first embodiment are, for example, a pressure boosting head valve 447, a pressure boosting rod valve 481, and a pressure boosting valve 483.

The pressure boosting head valve 447 is provided in place of the pressure boosting valve 47 of the first embodiment in the third flow path 43C connecting the accumulator 41 and the pressure boosting head side chamber 33h. The pressure boosting head valve 447 allows or prohibits the flow of the hydraulic fluid from the accumulator 41 to the pressure boosting head side chamber 33h, similarly to the pressure boosting valve 47.

The pressure boosting head valve 447 may have the same configuration as the pressure boosting valve 47, but here, a different configuration is exemplified. Specifically, for example, the pressure boosting head valve 447 is configured by a pilot type check valve. When the pilot pressure is not introduced, the pressure boosting head valve 447 allows the flow of the hydraulic fluid from the accumulator 41 to the booster head side chamber 33h, and prohibits the flow in the opposite direction to prevent the pilot pressure. When is introduced, both flows are prohibited.

The pressure boosting rod valve 481 is a flow rate control valve provided in a flow path (reference numeral omitted) connecting the pressure boosting rod side chamber 33r and the tank 37, and is discharged from the pressure boosting rod side chamber 33r to the tank 37, for example. Contributes to controlling the flow rate of the hydraulic fluid. By controlling this flow rate, for example, the boosting curve when the pressure is increased by the pressure increasing piston 35 is controlled.

The pressure boosting rod valve 481 may be one that performs pressure compensation (flow rate adjusting valve) or one that does not perform pressure compensation. Further, the control method of the pressure boosting rod valve 481 may be, for example, any of a spring type, an electromagnetic type and a pilot type, and a combination of two or more of these. The pressure boosting rod valve 481 may be a servo valve with feedback control or a proportional valve with open control. FIG. 9 shows a flow rate adjusting valve as a pressure boosting rod valve 481, which is closed at a normal position by a spring and is opened by sequentially operating an electromagnetic force and a pilot pressure.

The pressurizing valve 483 is provided in the seventh flow path 43G, and for example, allows or prohibits the flow of the hydraulic fluid from the pressure increasing rod side chamber 33r to the injection rod side chamber 29r. By allowing the flow, for example, pressurization is performed on the injection rod side chamber 29r before the start of injection.

The pressurizing valve 483 is composed of, for example, a pilot type check valve. When the pilot pressure is not introduced, the pressurizing valve 483 allows the flow of the hydraulic fluid from the boosting rod side chamber 33r to the injection rod side chamber 29r, and prohibits the flow in the opposite direction to the pilot pressure. When is introduced, both flows are prohibited.

Other configurations of the hydraulic pressure device 428 may be the same as those of the hydraulic pressure device 28 of the first embodiment. Note that, in FIG. 9, the pressure sensors 73 and 75, which are not shown in the first embodiment, are shown. The pressure sensor 73 detects the pressure in the injection rod side chamber 29r. The pressure sensor 75 detects the pressure in the injection head side chamber 29h. The control device 13 can specify the injection pressure based on the pressures of both sensors.

In addition to the functional unit described in the first embodiment, the control device 13 has, for example, a head control unit 13d that controls continuous application of hydraulic pressure from the accumulator 41 to the pressure increasing head side chamber 33h.

(Operation of injection device)
FIG. 10 is a timing chart for explaining the operation of the injection device 409, and is a diagram corresponding to FIG. 4 of the first embodiment.

The horizontal axis, the vertical axis, and the like in FIG. 10 are the same as those in FIG. However, FIG. 10 shows the operation of the pressure boosting head valve 447 instead of the operation of the pressure boosting valve 47. In addition, the operation of the pressurizing valve 483 and the boosting rod valve 481 has been added.

The injection device 409 is, for example, similarly to the first embodiment, pressurization to the injection rod side chamber 29r (to time point t0), low speed injection (generally time point t0 to t1), high speed injection (generally time point t1 to t2), and Pressurization (pressurization, approximately time point t3 ~) is performed in order. Specifically, it is as follows.

(Pressurization before the start of injection)
Before the start of pressurization, the state of the injection device 409 is basically the same as that of the first embodiment. Further, the pressure boosting head valve 447, the pressure boosting valve 483, and the pressure boosting rod valve 481, which are not provided in the first embodiment, are closed, for example.

Then, when the pressurization start condition described in the first embodiment is satisfied, the control device 13 opens the pressurization head valve 447, opens the pressurization valve 483, and sets the auxiliary valve 51 to the a position. As a result, the pressurization of the injection rod side chamber 29r before the start of injection is performed as in the first embodiment. In the illustrated example, the case where the timings of the above three valves are simultaneous is illustrated, but these timings are appropriately changed, such as opening the pressure boosting head valve 447 before or after the other valves. It is possible.

(Low speed injection, high speed injection and deceleration)
When the injection start condition described in the first embodiment is satisfied (time point t0), the control device 13 ends the pressurization to the injection rod side chamber 29r and starts low-speed injection. Specifically, for example, the control device 13 closes the pressurizing valve 483, thereby stopping the supply of hydraulic pressure from the boosting rod side chamber 33r to the injection rod side chamber 29r. Further, for example, the control device 13 sets the auxiliary valve 51 in a neutral position, and prohibits the discharge of the hydraulic fluid from the injection head side chamber 29h and the small diameter cylinder portion 33a to the tank 37. This prepares for the start of injection.

Here, unlike the first embodiment, the control device 13 keeps the booster head valve 447 open and continues to supply the hydraulic pressure from the accumulator 41 to the booster head side chamber 33h. However, since the discharge of the hydraulic fluid from the pressure boosting rod side chamber 33r is regulated by various valves (51, 481 and 483), the pressure boosting piston 35 does not move forward in theory, and the accumulator 41 There is no action of increasing the pressure of (pressure increasing head side chamber 33h) and applying it to the injection head side chamber 29h.

After that, from the start of injection to the start of pressure increase, the operation of the injection device 409 may be basically the same as the operation of the injection device 9 of the first embodiment. The pressure boosting head valve 447 is maintained in an open state, for example. The pressure increasing rod valve 481 is maintained in a closed state, for example. The pressurizing valve 483 is kept closed, for example.

(Pressure increase and pressure retention)
When the predetermined pressure increase start condition is satisfied, the injection device 409 starts the pressure increase (t3). The increase start condition may be set as appropriate.

For example, as the injection progresses, the plunger 23 naturally moves forward. Therefore, it may be a condition for starting the pressure increase that the plunger 23 reaches a predetermined pressure increase start position. The position of the plunger 23, which is used to determine whether or not the pressure boosting start position is reached, is detected by, for example, the position sensor 69. In addition, for example, in the case where the position control is performed so that the target position is realized moment by moment according to the time series of the target position of the plunger 23, and the speed is substantially controlled by this, the predetermined position is determined. It may be determined that the pressure increasing start position has been reached when the time of

Further, as the molten metal is filled in the cavity Ca, the plunger 23 decelerates due to the force received from the molten metal in the cavity Ca. Therefore, it may be a condition for starting the pressure increase that the injection speed drops to a predetermined pressure increase start speed. The injection speed, which is subjected to whether or not the pressure has dropped to the pressure increasing start speed, is obtained, for example, based on the detection value of the position sensor 69.

Further, as the molten metal is filled in the cavity Ca, the injection pressure (for example, the pressure applied to the molten metal by the plunger 23) increases. Therefore, the pressure increase start condition may be that the injection pressure has risen to a predetermined pressure increase start pressure. The injection pressure applied depending on whether or not the pressure has risen to the pressure increase start pressure is obtained, for example, based on the detected values of the pressure sensors 73 and 75.

The pressure increase start condition including the pressure increase start position, the pressure increase start speed and / or the pressure increase start pressure may be set by the operator, or may be set by the control device 13 based on other casting conditions or the like. ..

The control device 13 opens, for example, the pressure boosting rod valve 481 to start the pressure boosting. As a result, the pressure boosting piston 35 is allowed to move forward, and a pressure boosted higher than the pressure of the pressure booster head side chamber 33h is applied to the injection head side chamber 29h.

At this time, the control device 13 controls the flow rate of the hydraulic fluid discharged from the booster rod side chamber 33r by the booster rod valve 481 so that a desired booster curve can be obtained. The speed valve 49 is, for example, fully open. That is, the flow rate is not controlled by the speed valve 49. However, the desired booster curve may be obtained by controlling the flow rates of both valves.

The injection valve 45 is closed by self-closing or by introducing pilot pressure, as in the first embodiment. In the latter case, in consideration of the difference between the time delay of the pilot type valve and the time delay of the servo valve, the timing to output the command to close the injection valve 45 and the command to open the pressure boosting rod valve 481 are given. It may be slightly earlier than the output timing.

After that, as in the first embodiment, the injection pressure becomes constant (casting pressure) by balancing the force due to the increased pressure of the injection head side chamber 29h and the force due to the pressure received by the plunger 23 from the molten metal. .). At this time, the pressure of the injection rod side chamber 29r and the pressure of the pressure increasing rod side chamber 33r are, for example, tank pressures. Arbitrary casting pressure may be obtained by closing the pressure increasing rod valve 481 and / or the speed valve 49 at an appropriate time.

In the pressure holding step, the control device 13 maintains the state when the casting pressure is obtained. When the pressure holding step is completed, the control device 13 closes, for example, the pressure increasing head valve 447 and the pressure increasing rod valve 481. Others are the same as those in the first embodiment.

As described above, also in the present embodiment, the injection device 409 supplies the hydraulic fluid to the pressure increasing head side chamber 33h and applies the hydraulic pressure from the pressure increasing rod side chamber 33r to the injection rod side chamber 29r before the injection starts. Therefore, the same effect as that of the first and second embodiments is obtained. For example, it is possible to reduce the possibility of jumping at the start of injection.

Further, in the present embodiment, the hydraulic pressure device 428 includes an accumulator 41 that supplies the hydraulic fluid to the pressure boosting head side chamber 33h and a valve 481 for the pressure boosting rod that controls the flow rate of the hydraulic fluid discharged from the pressure boosting rod side chamber 33r. And have. The control device 13 is a head control unit that controls the hydraulic pressure device 428 so as to continuously supply the hydraulic fluid from the accumulator 41 to the pressure boosting head side chamber 33h from the (at least) pressure applied to the injection rod side chamber 29r to the completion of the pressure boosting. It has 13d and a pressure boosting control unit 13c that controls the hydraulic pressure device 418 so as to start the pressure boosting by opening the pressure boosting rod valve 481.

Therefore, for example, the boosting characteristic can be improved. Specifically, it is as follows.

In the first or second embodiment, there is a time delay between the time when the control device 13 outputs the command to open the pressure boosting valve 47 and the time when the pressure boosting piston 35 actually advances. As a result, there is a possibility that the pressure increase cannot be started at an appropriate timing. The reason is that, for example, it takes time for the hydraulic fluid from the pressure boosting valve 47 to the pressure booster head concubine 33h to be compressed.

However, in the present embodiment, since the hydraulic pressure is applied to the pressure increasing head side chamber 33h before the start of the pressure increasing, such an inconvenience does not occur. In addition, in FIG. 10, the effect is expressed by showing a steeper step-up curve from time points t3 to t4 as compared with FIGS. 4 and 7.

In the first or second embodiment, in order to eliminate the time delay as described above, the pressure boosting valve 47 is opened before the pressure boosting start condition described above is satisfied, and then the pressure boosting start condition is satisfied. At that time, control may be performed so that the opening degree of the speed valve 49 is for increasing the pressure.

However, in this case, various disadvantages also occur. For example, since the pressure boosting piston 35 is advanced before the start of pressure boosting, the stroke of the pressure boosting piston 35 becomes long. Further, when the pressure boosting piston 35 starts advancing before the start of pressure boosting (before the completion of injection in a narrow sense), the pressure in the injection head side chamber 29h increases due to the pressure boosting action, and the pressure increases from the accumulator 41 via the injection valve 45. Then, the flow rate of the hydraulic fluid flowing to the injection head side chamber 29h is reduced. As a result, unintended deceleration is achieved in the narrowly defined injection. In addition, the timing for opening the pressure boosting valve 47 must be set for each mold.

However, in the present embodiment, the liquid is previously restricted from the accumulator 41 to the pressure increasing head side chamber 33h in a state where the forward movement of the pressure increasing piston 35 and the pressure increasing action are restricted by prohibiting the discharge of the hydraulic fluid from the pressure increasing rod side chamber 33r. Pressure is applied. That is, the hydraulic pressure can be applied to the pressure boosting head side chamber 33h in advance without causing the inconvenience caused by opening the pressure boosting valve 47 before the start of the pressure boosting as described above.

Further, in the first or second embodiment, both the speed control in the injection in a narrow sense and the pressure control in the pressure increase are performed by controlling the flow rate of the speed valve 49. As a result, for example, when switching from speed control to pressure control, the injection pressure may temporarily decrease and the boosting characteristics may deteriorate. This is because, for example, the control of the speed valve 49 is started before the compression of the hydraulic fluid in the pressure increasing head side chamber 33h is completed. Further, for example, when the target value of the injection speed is changed, it is necessary to correct the timing of switching from the speed control to the pressure control. In addition, the control accuracy may decrease.

However, in the present embodiment, the pressure is controlled by controlling the flow rate of the hydraulic fluid discharged from the pressure increasing rod side chamber 33r. From another point of view, the flow rate control for speed control and the flow rate control for pressure control are performed separately. As a result, the above-mentioned inconvenience is eliminated. For example, the boosting characteristic is improved. The improvement of the boosting property facilitates, for example, casting of a thin-walled die-cast product that cools quickly.

Further, if the amount of hot water supplied varies between a plurality of shots, the relative relationship between the position of the plunger 23 and the progress of filling the molten metal varies, and the quality of the die-cast product also varies. However, in the present embodiment, by starting the pressure increase based on the pressure increase start speed and / or the pressure increase start pressure, the pressure increase can be started at an appropriate timing even if the amount of hot water supplied varies. Therefore, in combination with the improvement of the boosting characteristics, high quality die-cast products can be stably produced.

Compared to the present embodiment, the first and second embodiments have an effect that, for example, only one flow rate control valve is required, and the cost can be reduced. Therefore, any one of the first to third embodiments may be appropriately selected according to the specifications and the like required by the user.

In the third embodiment, the pressure increasing rod valve 481 is an example of the pressure increasing side flow rate control valve.

<Deformation example of cylinder part>
8 (a) and 8 (b) show a modified example of the cylinder portion. The following cylinder portion may be applied to any of the first to third embodiments, but in the following description, the reference numerals of the first embodiment and the like are used. Further, even if there is a difference from the first embodiment, the same reference numerals as those of the first embodiment are attached to the configurations in which the difference is mainly the dimensions.

(Fourth modification)
In the embodiment, the inner diameter d4 of the small diameter cylinder portion 33a is made smaller than the inner diameter d1 of the injection cylinder portion 29, and the stopper 36 is configured by the step. On the other hand, in the injection cylinder 301 according to the modification shown in FIG. 8A, the inner diameter d4 is equivalent to the inner diameter d1.

The stopper 303 that defines the retreat limit of the injection piston 31 is composed of a convex portion that protrudes from the inner surface of the injection cylinder portion 29 and the inner surface of the small diameter cylinder portion 33a. This convex portion extends (formed in an annular shape) over the entire circumference of the inner peripheral surface of the injection cylinder portion 29, for example.

As described above, the inner diameter d4 does not have to be smaller than the inner diameter d1. Further, from another viewpoint, the stopper is not limited to the one formed by the step on the inner surface between the cylinder chambers. Although not particularly shown, the inner diameter d4 may be larger than the inner diameter d1.

In addition, in FIG. 8A, as a method of constructing the stopper 303, a member having a tubular portion fitted to the inner surface of the injection cylinder portion 29 and a flange portion protruding outward from the tubular portion is provided in the injection cylinder portion. The case where it is interposed between 29 and the small diameter cylinder portion 33a is illustrated. However, as described in the description of the embodiment, the number of members constituting the cylinder portion and the like and the division position thereof may be appropriately set.

(Fifth modification)
In the embodiment, the pressure boosting cylinder portion 33 is provided so as to be connected in series (for example, coaxially) with the injection cylinder portion 29. On the other hand, in the injection cylinder 311 shown in FIG. 8B, the pressure boosting cylinder portion 33 is provided so as to intersect (for example, orthogonally) with the injection cylinder portion 29.

From another viewpoint, the small diameter cylinder portion 33a does not directly communicate with the injection head side chamber 29h, but communicates with the injection head side chamber 29h via the flow path 313. In the illustrated example, the flow path 313 is configured in the block-shaped member, but may be configured by a tubular member made of a rigid body or a flexible hose. Although not particularly shown, the injection cylinder portion 29 and the pressure boosting cylinder portion 33 may not be directly fixed.

The technique according to the present disclosure is not limited to the above embodiments, and may be implemented in various embodiments.

The molding machine is not limited to the die casting machine. For example, the molding machine may be another metal molding machine, an injection molding machine for molding a resin, or a molding machine for molding a material obtained by mixing wood powder with a thermoplastic resin or the like. There may be. The molding material is not limited to a liquid material, and may have a certain viscosity. For example, the metal material may be a solid-liquid coexisting metal (semi-solidified metal or semi-molten metal).

Further, the molding machine is not limited to the horizontal compaction horizontal injection, and may be, for example, vertical compaction vertical injection, horizontal compaction vertical injection, or vertical compaction horizontal injection. When the molding machine is a die casting machine, the die casting machine is not limited to the cold chamber machine and may be a hot chamber machine.

The configurations other than the injection device such as the mold clamping device may be various known configurations. For example, in the embodiment, a toggle type is shown as the mold clamping device, but the mold clamping device may be a composite type that uses a separate drive source for the mold opening / closing and the mold clamping. Further, for example, the mold clamping device may be a fully electric type or a fully hydraulic type.

When the injection cylinder portion and the pressure boosting cylinder portion are connected in series, both may be eccentric. Further, the small-diameter cylinder portion and the large-diameter cylinder portion may be eccentric.

The hydraulic circuit shown in the embodiment is only an example, and the flow path and the valve may be appropriately set. For example, in the embodiment, the connection and disconnection of the boost rod concubine with the tank and / or the pump is completely shared with the connection and disconnection of the injection rod concubine with the tank and / or the pump, but can be controlled separately. May be provided with a flow path and a valve. A valve may be provided in the flow path communicating the boost rod side chamber and the injection rod side chamber.

In injection, the hydraulic fluid discharged from the injection rod side chamber may be returned to the injection head side chamber via a flow rate control valve (speed valve) instead of the tank. That is, a run-around circuit may be provided. The hydraulic pressure device may have a meter-in circuit in addition to the meter-out circuit.

The hydraulic pressure source that supplies the hydraulic fluid to the booster head side chamber for pressurizing the injection rod side chamber before the start of injection is not limited to the accumulator, and may be, for example, a pump. From another point of view, the hydraulic pressure source that supplies the hydraulic fluid to the booster head side chamber for pressurization may be the same as the hydraulic pressure source that supplies the hydraulic fluid to the injection head side chamber for injection. However, it may or may not be the same as the hydraulic pressure source that supplies the hydraulic fluid to the pressure increasing head side chamber for pressure increasing and / or pressure holding. In the embodiment, the accumulator 41 is used for both injection and pressure increasing, but an accumulator for injection and an accumulator for pressure increasing may be provided.

The pressurization to the injection rod concubine before the start of injection may be started at an appropriate time after the retreat of the boosting piston in the previous cycle, and as mentioned in the description of the embodiment, until the start of injection. It doesn't have to be continued. Compared to the case where it is assumed that the pressure in the injection rod concubine at the start of injection (for example, when the speed valve 49 is opened or when the drive motor 283 is driven) is not pressurized before the start of injection. It should be a little higher. Conversely, after the retreat of the booster piston in the previous cycle, the hydraulic fluid is supplied to the booster head side chamber and the hydraulic pressure in the booster rod side chamber is applied to the injection rod side chamber, and the subsequent injection is performed. If the pressure in the injection rod side chamber is slightly higher than in the case where it is assumed that the above operation is not performed at the start, it can be said that the pressurization before the start of injection is performed.

The configuration shown in the embodiment is conceived from the problem of suppressing jumping that occurs when the flow rate of the hydraulic fluid discharged from the injection rod side chamber is limited by the meter-out circuit. However, the configuration or operation obtained to solve the problem does not presuppose a meter-out circuit and may not be used for the purpose of suppressing jumping. For example, as can be understood from the operation of the low-speed injection of the second embodiment, in a state where the meter-out circuit is not functioning and a relief valve is provided, the injection rod side chamber is given before the start of injection. The pressure contributes to improving the accuracy of controlling the position and speed of the plunger by the electric motor by keeping the pressure fluctuation of the injection rod side chamber constant.

From the second embodiment, the following injection device that does not require pressurization before the start of injection can be extracted.
An injection piston rod connected to the rear of the plunger that pushes the molding material into the front mold, an injection piston fixed to the rear of the injection piston rod, and an injection cylinder that slidably accommodates the injection piston. An injection cylinder having a portion, wherein the inside of the injection cylinder portion is divided into a front injection rod side chamber and a rear injection head side chamber.
A hydraulic device capable of supplying the hydraulic fluid to the injection head side chamber, and
An electric drive unit capable of driving the injection piston rod with respect to the injection cylinder unit,
Have and
The hydraulic pressure device is an injection device having a relief valve for discharging a hydraulic fluid from the injection rod side chamber when the pressure in the injection rod side chamber exceeds a predetermined pressure.

In the above injection device, for example, even if pressurization is not performed before the start of injection, if the discharge of the hydraulic fluid from the injection rod concubine is allowed only from the relief valve during low-speed injection, it is possible to start high-speed injection. The pressure in the injection rod side chamber rises to the set pressure of the relief valve. As a result, jumping at the start of high-speed injection is suppressed.

In the injection device extracted from the third embodiment, in which the pressure increase is started by opening the pressure increase side flow control valve while continuously supplying the hydraulic fluid to the pressure increase head side chamber, for example, a booster curve is used. The effect that can be improved is played. Further, in the above-mentioned injection device, "before the start of pressure increase" is not limited to before the start of injection in the narrow sense (for example, before the start of low-speed injection), but after the start of injection in the narrow sense, unlike the third embodiment. It may be after the high speed injection is started. However, it is preferable that the accumulator starts applying the hydraulic pressure to the pressure boosting head concubine at the timing when the compression of the hydraulic fluid in the pressure boosting head side chamber is completed before the pressure boosting starts.

1 ... Die cast machine, 9 ... Injection device, 13 ... Control device, 13a ... Pressure control unit, 21 ... Sleeve, 23 ... Plunger, 27 ... Injection cylinder, 28 ... Hydraulic device, 29 ... Injection cylinder part, 29r ... Injection Rod side chamber, 29h ... Injection head side chamber, 31 ... Injection piston, 32 ... Injection piston rod, 33 ... Boost cylinder part, 33a ... Small diameter cylinder part, 33b ... Large diameter cylinder part, 33r ... Pressure boosting rod side chamber, 33h ... Increase Pressure head side chamber, 35 ... Boosting piston, 35a ... Small diameter piston, 35b ... Large diameter piston, 101 ... Mold.

Claims (9)

An injection cylinder that drives a plunger that pushes the molding material into the front mold,
A hydraulic device that controls the flow of hydraulic fluid in the injection cylinder, and
A control device that controls the hydraulic pressure device and
Have and
The injection cylinder
An injection piston rod connected to the rear of the plunger,
The injection piston fixed to the rear of the injection piston rod,
An injection cylinder portion that slidably accommodates the injection piston and whose inside is divided into a front injection rod side chamber and a rear injection head side chamber by the injection piston.
The small-diameter cylinder portion leading to the injection head side chamber and
A large-diameter cylinder portion that is connected in series to the small-diameter cylinder portion and has a larger diameter than the small-diameter cylinder portion.
A small-diameter piston slidably housed in the small-diameter cylinder,
It is fixed in series with the small-diameter piston and is slidably housed in the large-diameter cylinder portion. It has a large-diameter piston, which is partitioned into a head side chamber, and
The control device controls the hydraulic device so as to supply a hydraulic fluid to the pressure increasing head side chamber and apply a pressurization to apply the hydraulic pressure from the pressure increasing rod side chamber to the injection rod side chamber before the start of injection. An injection device that has a pressurization control unit. The injection device according to claim 1, wherein the pressurization control unit controls the hydraulic device so as to release pressure from the injection head concubine at the time of pressurization. The injection device according to claim 1 or 2, wherein the injection cylinder has a stopper fixed to the injection cylinder portion to regulate the retreat of the injection piston. The small-diameter cylinder portion continues in series with respect to the rear side of the injection cylinder portion.
The inner diameter of the small diameter cylinder portion is smaller than the inner diameter of the injection cylinder portion.
The injection device according to claim 3, wherein the stopper is configured by a step between the injection cylinder portion and the small diameter cylinder portion. The pressure-receiving area S3 of the large-diameter piston in the pressure-increasing head side chamber of the large-diameter piston with respect to the ratio S1 / S2 of the pressure-receiving area S1 in the injection head side chamber of the injection piston to the pressure-receiving area S2 of the injection rod side chamber of the injection piston. The ratio (S3 / S4) / (S1 / S2) of the ratio S3 / S4 to the pressure receiving area S4 in the pressure increasing rod side chamber of the large-diameter piston is 0.9 or more and 1.2 or less.
The injection device according to any one of claims 1 to 4. The hydraulic pressure device has a flow rate control valve that controls the flow rate of the hydraulic fluid discharged from the injection rod side chamber.
The control device is
An injection control unit that controls the hydraulic pressure device to start injection by supplying the hydraulic fluid to the injection head concubine and opening the flow rate control valve.
The invention according to any one of claims 1 to 5, further comprising a pressure increasing control unit that controls the hydraulic pressure device so as to increase the pressure by supplying a hydraulic fluid to the pressure increasing head concubine. Injection device. It further has an electric drive unit capable of driving the injection piston rod with respect to the injection cylinder unit.
The hydraulic pressure device is
A relief valve that discharges the hydraulic fluid from the injection rod side chamber when the pressure in the injection rod side chamber exceeds a predetermined pressure.
It has a flow rate control valve that controls the flow rate of the hydraulic fluid discharged from the injection rod side chamber.
The control device is
The low-speed injection is started by the driving force of the electric drive unit, and then the hydraulic fluid is supplied to the injection head concubine and the flow control valve is opened to perform high-speed injection at a higher speed than the low-speed injection. An electric drive unit, an injection control unit that controls the hydraulic pressure device, and
The invention according to any one of claims 1 to 5, further comprising a pressure increasing control unit that controls the hydraulic pressure device so as to increase the pressure by supplying a hydraulic fluid to the pressure increasing head concubine. Injection device. The hydraulic pressure device is
An accumulator that supplies the hydraulic fluid to the booster head concubine,
It has a pressure booster side flow rate control valve that controls the flow rate of the hydraulic fluid discharged from the pressure booster rod side chamber.
The control device is
A head control unit that controls the hydraulic pressure device so as to continuously supply the hydraulic fluid from the accumulator to the pressure boosting head concubine from the pressurization to the completion of the pressure boosting.
The injection device according to any one of claims 1 to 7, further comprising a pressure boosting control unit that controls the hydraulic pressure device so as to start the pressure boosting by opening the pressure boosting side flow rate control valve. .. The injection device according to any one of claims 1 to 8 , and the injection device.
A mold clamping device that clamps the mold and
An extruder that extrudes a molded product from the mold,
Has a molding machine.

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