JP2019181537A - Injection machine and molding machine - Google Patents

Abstract

To provide an injection machine for realizing either or both of suppression in jumping and improvement in pressure increasing performance.SOLUTION: An injection device 9 includes a booster injection cylinder 27 connected to a rear part of a plunger 23 for pushing a mold material into a front mold 101, a hydraulic pressure device 28 for controlling the flow of the working fluid in the injection cylinder 27, and a control device 13 for controlling the hydraulic pressure device 28. The inside of the injection cylinder 27 is partitioned into an injection rod side chamber 29r and an injection head side chamber 29h by an injection piston 31. The inside of the injection cylinder is also partitioned into the inside of a small-diameter cylinder portion 33a, a booster rod side chamber 33r and a booster head side chamber 33h by a booster piston 35. The control device 13 has a pressure control section 13a for controlling the hydraulic pressure device 28 so as to supply the hydraulic fluid to the booster head side chamber 33h and to apply the fluid pressure to the injection rod side chamber 29r from the booster rod side chamber 33r before starting the injection.SELECTED DRAWING: Figure 2

Description

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

  2. Description of the Related Art As an injection device, a device that drives a plunger that pushes a molding material into a mold by an injection cylinder is known (for example, Patent Document 1). The injection cylinder has an injection piston rod connected to the plunger, an injection piston fixed to the injection piston rod, and an injection cylinder portion that houses the injection piston. The inside of the injection cylinder section is partitioned into an injection rod side chamber on the side where the injection piston rod extends from the injection piston, and an injection head side chamber on the opposite side. Then, when the working fluid (for example, oil) is supplied to the injection head side chamber, the injection piston moves to the injection piston rod side, and thereby the plunger moves forward toward the mold. The speed of the injection cylinder (in other words, the injection speed) is controlled by, for example, a flow 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).

  Patent Document 1 discloses an accumulator connected to an injection rod side chamber in order to suppress surge pressure. Although not specifically illustrated, an injection cylinder having a pressure increasing piston capable of increasing the pressure in the injection head side chamber is known.

JP-A-6-297128

  When the meter-out circuit is used, ideally, the injection piston moves forward at a speed corresponding to the flow rate of the hydraulic fluid discharged from the injection rod side chamber. However, actually, 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 from the injection piston to the hydraulic fluid in the injection rod side chamber. The injection piston may move forward at a speed exceeding the speed corresponding to the flow rate of the hydraulic fluid discharged from the engine. That is, so-called jumping may occur. As a result, the quality of the molded product may be reduced.

  Therefore, it is preferable to provide an injection apparatus and a molding machine that can realize at least one of a reduction in jumping and an improvement in pressure-up performance.

  An injection device according to an 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 a flow of hydraulic fluid in the injection cylinder, and the hydraulic device. A control device for controlling the injection cylinder, wherein the injection cylinder is configured to slide an injection piston rod connected to a rear portion of the plunger, an injection piston fixed to the rear portion of the injection piston rod, and the injection piston. An injection cylinder portion that is movably accommodated and 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; The small-diameter cylinder portion continues in series and has a large-diameter cylinder portion having a diameter larger than that of the small-diameter cylinder portion, and is slidably accommodated in the small-diameter cylinder portion. A small-diameter piston, which is fixed in series to the small-diameter piston, is slidably accommodated in the large-diameter cylinder portion, and the inside of the large-diameter cylinder portion is a pressure increasing rod side chamber on the small-diameter cylinder portion side, A large-diameter piston partitioned into a pressure-increasing head side chamber on the opposite side, and the control device supplies hydraulic fluid to the pressure-increasing head side chamber before the injection starts to A pressurization control unit is provided for controlling the hydraulic pressure device so as to apply a hydraulic pressure from the rod side chamber to the injection rod side chamber.

  In one example, the pressurization control unit controls the hydraulic pressure device so as to perform pressure relief of the ejection head side chamber during the pressurization.

  In one example, the injection cylinder has a stopper that restricts retraction of the injection piston fixed to the injection cylinder portion.

  In one example, the small diameter cylinder part continues in series with the rear side of the injection cylinder part, and the internal diameter of the small diameter cylinder part is smaller than the internal diameter of the injection cylinder part, and the injection cylinder part and the small diameter cylinder The stopper is constituted by a step between the two parts.

  In one example, the pressure receiving area S3 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 in 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.

  In one example, the hydraulic device has a flow rate control valve that controls a 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 An injection control unit that controls the hydraulic pressure device to start injection by opening a flow control valve, and the hydraulic pressure device is controlled to increase pressure by supplying hydraulic fluid to the pressure increasing head side chamber. A pressure increase control unit.

  In one example, the injection device further includes an electric drive unit capable of driving the injection piston rod with respect to the injection cylinder unit, and the hydraulic device is configured such that the pressure in the injection rod side chamber is a predetermined pressure. A relief valve for discharging the hydraulic fluid from the injection rod side chamber when the pressure exceeds, and a flow rate control valve for controlling the flow rate of the hydraulic fluid discharged from the injection rod side chamber, the control device, 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 rate control valve is opened to perform high-speed injection at a speed higher than the low-speed injection. An electric drive unit and an injection control unit that controls the hydraulic device; and a pressure increase control unit that controls the hydraulic device to increase pressure by supplying hydraulic fluid to the pressure increasing head side chamber; It has.

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

  An injection device according to an 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 a flow of hydraulic fluid in the injection cylinder, and the hydraulic device. A control device for controlling the injection cylinder, wherein the injection cylinder is configured to slide an injection piston rod connected to a rear portion of the plunger, an injection piston fixed to the rear portion of the injection piston rod, and the injection piston. An injection cylinder portion that is movably accommodated and 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; The small-diameter cylinder portion continues in series and has a large-diameter cylinder portion having a diameter larger than that of the small-diameter cylinder portion, and is slidably accommodated in the small-diameter cylinder portion. A small-diameter piston, which is fixed in series to the small-diameter piston, is slidably accommodated in the large-diameter cylinder portion, and the inside of the large-diameter cylinder portion is a pressure increasing rod side chamber on the small-diameter cylinder portion side, A large-diameter piston divided into a pressure-increasing head side chamber on the opposite side, and the hydraulic device includes an accumulator that supplies hydraulic fluid to the pressure-increasing head side chamber, and the pressure-increasing rod side chamber A pressure-increasing-side flow rate control valve that controls the flow rate of the hydraulic fluid discharged from the engine, and the control device continues from the accumulator to the pressure-increasing head side chamber from the start of pressure increase until the completion of pressure increase A head control unit that controls the hydraulic pressure device to supply hydraulic fluid, and a pressure increase control unit that controls the hydraulic pressure device to start pressure increase by opening the pressure increase side flow control valve. Have.

  In one example, the hydraulic device has a pressurizing valve capable of allowing and prohibiting the flow of hydraulic fluid from the pressure increasing rod side chamber to the injection rod side chamber, and the control device is configured to A pressurization control unit that controls the pressurization valve so as to apply a hydraulic pressure from the pressure increasing rod side chamber to the injection rod side chamber;

  In one example, the hydraulic pressure device has a flow rate control valve that controls a flow rate of 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 device is controlled to be fully open.

  The molding machine which concerns on 1 aspect of this indication has said injection apparatus, the mold clamping apparatus which clamps the said metal mold | die, and the extrusion apparatus which extrudes a molded article from the said metal mold | die.

  According to said structure, at least one of reduction of the possibility of jumping and improvement of pressure | voltage rise performance is realizable.

The schematic diagram which shows the structure of the die-casting machine which has the injection apparatus which concerns on 1st Embodiment of this indication. The schematic diagram which shows the structure of the hydraulic system in the injection device of FIG. FIG. 3A to FIG. 3C are schematic cross-sectional views showing an enlarged part of the injection cylinder. The timing chart for demonstrating operation | movement of the injection apparatus of FIG. The schematic diagram which shows the structure of the drive mechanism in the injection device which concerns on 2nd Embodiment of this indication. The schematic diagram which shows the structure of the hydraulic system in the injection device of FIG. The timing chart for demonstrating operation | movement of the injection apparatus of FIG. FIG. 8A and FIG. 8B are schematic views showing a modification of the injection cylinder. The schematic diagram which shows the principal part structure of the injection device which concerns on 3rd Embodiment of this indication. The timing chart for demonstrating operation | movement of the injection apparatus of FIG.

  Hereinafter, an embodiment and its modification 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 differences from the already described mode (basically the first embodiment) will be described. The points not particularly mentioned may be the same as those already described. Moreover, the code | symbol attached | subjected to the structure of the already demonstrated aspect may be attached | subjected about the structure which is the same as that of the structure of the already demonstrated aspect, or similar.

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

  The die casting machine 1 injects a molten metal material (molten metal) into a mold 101 (a space such as a cavity Ca, etc .; the same applies hereinafter), and solidifies the molten metal in the mold 101. Product (molded product). 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 movable mold 105 is shown by one type of hatching, but these molds may be of a direct engraving 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 includes, 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 body 3 includes, for example, a mold clamping device 7 that opens and closes and molds the mold 101, an injection device 9 that injects molten metal into the mold 101, and a die-cast product that is a fixed mold 103 or a movable mold 105 ( In FIG. 1, it has the extrusion apparatus 11 extruded from the moving metal mold | die 105). In the machine body 3, the configuration other than the injection device 9 (for example, the configuration 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 and closes the mold. Further, the mold clamping device 7 performs mold clamping by applying a mold clamping force corresponding to the extension amount of the tie bar (reference number omitted) to the mold 101. A cavity Ca having the same shape as the molded product is formed in the clamped mold 101. The injection device 9 injects and fills molten metal into the cavity Ca. The molten metal filled in the cavity Ca is deprived of heat by the mold 101 and cooled and solidifies. Thereby, a molded article is formed. Thereafter, the mold clamping device 7 opens the mold by moving the moving mold 105 away from the fixed mold 103. At this time or thereafter, the extrusion device 11 pushes out the molded product from the moving mold 105.

  The control unit 5 includes, for example, a control device 13 (see FIG. 2) that performs various calculations and outputs a control command, a display device 15 that displays an image, and an input device 17 that receives an operator's input operation. ing. From another viewpoint, the control unit 5 includes, 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 in a control panel and an operation unit 19 (not shown), for example. The control device 13 may be divided or distributed as appropriate. 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 the operation unit 19, for example. For example, the operation unit 19 is provided in a fixed portion of the mold clamping device 7. The display device 15 is configured by a touch panel including a liquid crystal display or an organic EL display, for example. The input device 17 is configured by, for example, a mechanical switch and the touch panel.

(Configuration of injection device)
The injection device 9 includes, for example, a sleeve 21 that communicates with the mold 101, a plunger 23 that can slide within 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, and the opposite side may be referred to as the rear.

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

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

  When the mold clamping of the mold 101 by the mold clamping device 7 is completed, 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, when the plunger 23 slides forward in the sleeve 21 from the illustrated position, the molten metal in the sleeve 21 is pushed out (injected) into the mold 101.

(Configuration of injection drive unit)
FIG. 2 is a schematic diagram illustrating the configuration of the injection driving 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, a supply of hydraulic fluid (for example, oil) to the injection cylinder 27, and the like. And a hydraulic device 28 (FIG. 2) to perform.

(Configuration of injection cylinder)
FIG. 3A to FIG. 3C are schematic cross-sectional views showing a part of the injection cylinder 27 in an enlarged manner. 3A to 3C show different operating states of the injection cylinder 27. FIG.

  As shown in FIGS. 2 and 3 (a) to 3 (c), the injection cylinder 27 is constituted by, for example, a so-called directly connected pressure-increasing cylinder. Specifically, for example, the injection cylinder 27 includes an injection cylinder part 29, an injection piston 31 that can slide inside the injection cylinder part 29, and an injection piston that is fixed to the injection piston 31 and extends from the injection cylinder part 29. It has a rod 32, a pressure increasing cylinder portion 33 that communicates with the injection cylinder portion 29, and a pressure increasing piston 35 that can slide inside the pressure increasing cylinder portion 33.

  The injection cylinder part 29 is, for example, a cylindrical body having a circular inner cross-sectional shape. The injection piston 31 has a substantially cylindrical shape, for example. The inside of the injection cylinder part 29 includes an injection rod side chamber 29r on the side (front) from which the injection piston rod 32 extends by an injection piston 31, and an injection head side chamber 29h on the opposite side (rear side) (reference numeral is FIG. 3 (c)). ) And is divided. By selectively supplying 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, 3A and 3B), 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 also be expressed as the existence of the ejection head side chamber 29h.

  The pressure-increasing cylinder portion 33 is, for example, connected in series (for example, coaxially) behind the small-diameter cylinder portion 33a communicating with the injection head side chamber 29h and behind the small-diameter cylinder portion 33a, and has a large diameter larger than the small-diameter cylinder portion 33a. And a cylinder portion 33b. Each of the small-diameter cylinder part 33a and the large-diameter cylinder part 33b is a cylindrical body having a circular internal cross-sectional shape. The small-diameter cylinder part 33a is provided, for example, in series (for example, coaxially) at the rear end of the injection cylinder part 29 so that the inside thereof communicates with the injection head side chamber 29h.

  3 (a) to 3 (c) are schematic diagrams, one hatching is attached to the injection cylinder part 29 and the pressure increasing cylinder part 33, but actually a plurality of members are provided. May be connected to form the injection cylinder part 29 and the pressure-increasing cylinder part 33. The joints of the plurality of members may or may not coincide with the boundary between the injection cylinder part 29 and the pressure increasing cylinder part 33. 3 (a) to 3 (c) are schematic diagrams, the injection cylinder 29 and the pressure-increasing cylinder 33 are shown with a constant thickness. May be different. The same applies to other drawings to be described later.

  The pressure-increasing piston 35 is fixed in series (for example, coaxially) to the small-diameter piston 35a that can slide the small-diameter cylinder portion 33a, and the large-diameter piston 35b that can slide the large-diameter cylinder portion 33b. And have. The small-diameter piston 35a and the large-diameter piston 35b are each substantially cylindrical, for example. The inside of the large-diameter cylinder portion 33b is composed of a pressure-increasing rod side chamber 33r on the small-diameter cylinder portion 33a side and a pressure-increasing head side chamber 33h on the opposite side by the large-diameter piston 35b. )).

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

  When the pressure increasing rod side chamber 33r is depressurized, the pressure receiving area in the pressure increasing head side chamber 33h of the large diameter piston 35b is larger than the pressure receiving area in the small diameter cylinder portion 33a of the small diameter piston 35a. A pressure higher than the pressure received from the hydraulic fluid in the pressure-increasing head side chamber 33h can be applied to the hydraulic fluid in the small diameter cylinder portion 33a and the injection head side chamber 29h. Thereby, the injection cylinder 27 exhibits a pressure increasing function for applying a hydraulic pressure higher than the applied hydraulic pressure behind the injection piston 31.

Note that the pressure receiving area of the piston in the description of the present embodiment is an area obtained by projecting the area where 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 not affected by the unevenness of the surface of the piston exposed in the cylinder chamber. Further, unless the piston has a unique shape, the pressure receiving area is substantially the same as the cross-sectional area of the piston. If the piston has a cylindrical shape with a diameter d, the pressure receiving area is π × (d / 2) ² .

  The inner diameter of the small diameter cylinder portion 33a is, for example, smaller than the inner diameter of the injection cylinder portion 29 (injection head side chamber 29h). Thereby, a step is formed between the injection cylinder part 29 and the pressure increasing cylinder part 33. This step functions as a stopper 36 (reference numeral is FIG. 3 (a) to FIG. 3 (c)) that abuts the injection piston 31 from the rear and restricts the backward movement of the injection piston 31 (defines the backward limit). . For example, the stopper 36 is in contact with 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 disposed coaxially with the plunger 23, for example. 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 to a mold clamping device (not shown). Accordingly, the plunger 23 moves forward or backward in the sleeve 21 by the movement of the injection piston 31 relative to the injection cylinder portion 29.

(Principles of jumping suppression)
In the above-described configuration, for example, the hydraulic fluid is supplied to the injection head side chamber 29h, and the injection is performed when the injection piston 31 moves forward. 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, when the supply of the hydraulic fluid to the injection head side chamber 29h is started, this 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. There is a possibility that the injection piston 31 is driven at a speed exceeding the speed (jumping occurs).

  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 two cylinder chambers as a whole are prohibited from discharging the hydraulic fluid. The hydraulic fluid is supplied to the side chamber 33h. As a result, the pressure increasing piston 35 moves forward with a relatively small movement amount δ (FIG. 3B), and the hydraulic fluid in the pressure increasing rod side chamber 33r and the injection rod side chamber 29r is compressed. At this time, the small diameter cylinder part 33a is, for example, pressure released.

  Since the pressure receiving area in the pressure increasing rod side chamber 33r of the large diameter piston 35b is smaller than the pressure receiving area in the pressure increasing head side chamber 33h of the large diameter piston 35b, the large diameter piston 35b receives pressure from the hydraulic fluid in the pressure increasing head side chamber 33h. Higher pressure can be applied to the hydraulic fluid in the pressure-increasing rod side chamber 33r.

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

  Here, the pressure receiving area of the injection piston 31 in the injection rod side chamber 29 r 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 a pressure receiving area in the injection rod side chamber 29r. Accordingly, the injection piston 31 can increase the pressure of the injection head side chamber 29h to generate a pressure increasing action that is applied to the injection rod side chamber 29r. This pressure increasing action is also a factor causing jumping. Therefore, for example, the pressure increasing action on the pressure increasing rod side chamber 33r by the pressure increasing piston 35 is equal to or greater than the pressure increasing action in the injection piston 31 or larger than the pressure increasing action in the injection piston 31. Good.

  Specifically, for example, as shown in FIG. 3C, the pressure receiving area in the injection head side chamber 29h of the injection piston 31 is S1, and the pressure receiving area in the injection rod side chamber 29r of the injection piston 31 is S2 (<S1). . For example, when the difference between the two pressure increase ratios is about 10%, the two pressure increase ratios are assumed to be substantially equal. 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. For example, the area ratio S3 / S4 may be 0.9 times or more (that is, equal to or greater) than the area ratio S1 / S2. For example, the area ratio S3 / S4 may be 1.1 times or more and 1.2 times or less of the area ratio S1 / S2. For example, combining these, the area ratio S3 / S4 may be 0.9 times or more and 1.2 times or less of 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 piston 35b is d3, and the diameter of the small piston 35a is d4. Further, it is assumed that each of these shapes is a cylindrical shape. In this case, in a mode in which S1 / S2 and S3 / S4 are substantially equivalent, d1 / d2 and d3 / d4 are substantially equivalent.

(Configuration of hydraulic device)
The hydraulic device 28 may have an appropriate configuration as long as the operation of increasing the pressure of the injection rod side chamber 29r in advance by the pressure increasing piston 35 can be performed in addition to the normal injection operation. Below, the example is demonstrated.

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

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

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

  The accumulator 41 is, for example, of a weight type, a spring type, a gas 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 includes a cylinder part 41a and a piston 41b that partitions the cylinder part 41a into a liquid chamber 41e and a gas chamber 41f. The liquid chamber 41e contains hydraulic fluid, and the gas chamber 41f is filled with gas (for example, air or nitrogen). When the hydraulic fluid is supplied to the liquid chamber 41e and the piston 41b moves to the gas chamber 41f side, the gas in the gas chamber 41f is compressed, and the accumulator 41 is accumulated. Further, the working fluid is discharged from the liquid chamber 41e using the pressure of the gas. The accumulator 41 contributes to the supply of hydraulic fluid to the injection cylinder 27, for example.

  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 accumulator 41.

  The second flow path 43B connects the accumulator 41 (liquid chamber 41e) and the ejection head side chamber 29h. Thereby, for example, the working 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 working fluid in the injection rod side chamber 29r whose volume decreases as the injection piston 31 moves forward can be discharged to the tank 37.

  The fifth flow path 43E has one end connected to the injection rod side chamber 29r and the other end 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.

  A plurality of flow paths (43A-43H etc.) are constituted by a steel pipe, a flexible hose, or a metal block, for example. Some of the plurality of flow paths may be shared as appropriate. For example, in the example of FIG. 2, a part of the first flow path 43A to the third flow path 43C on the accumulator 41 side is shared, and the fourth flow path 43D, the fifth flow path 43E, and the seventh flow path 43G are 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 (part of which is not shared with the other flow paths (43A and 43C)), and allows the working fluid to flow from the accumulator 41 to the injection head side chamber 29h. Allow or prohibit flow. The injection valve 45 is constituted by, for example, a pilot type check valve. When the pilot pressure is not introduced, the injection valve 45 allows the flow of hydraulic fluid from the accumulator 41 to the injection head side chamber 29h and vice versa. Flow in the direction is prohibited, and when the pilot pressure is introduced, both flows are prohibited. The injection valve 45 also contributes to the prevention of backflow of hydraulic fluid from the injection head side chamber 29h.

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

  The pressure-increasing valve 47 may be configured by a non-leak valve that has relatively little leakage of hydraulic fluid in the closed state. The non-leak valve is often described as being a non-leak valve in its catalog or specification, and based on the description, it can be specified whether or not it is a non-leak valve.

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

  Here, in the illustrated example, the seventh flow path 43G that connects 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 permitted or prohibited.

  The auxiliary valve 51 is constituted by, for example, a four-port three-position switching valve, and switches connection and disconnection between the four ports. Each port is connected to, for example, the fifth flow path 43E (injection rod side chamber 29r), the sixth flow path 43F (injection head side chamber 29h and the small diameter cylinder portion 33a), the pump 39, or the tank 37. In the illustrated example, the eighth flow path 43H that connects one port of the auxiliary valve 51 and the tank 37 is shared with a portion of the fourth flow path 43D that is downstream of the speed valve 49. Yes.

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

  For example, the auxiliary valve 51 cuts off the connection of the four ports at the center position (neutral position and / or normal position) of the drawing. Hereinafter, this position may be referred to as a closed position.

  The auxiliary valve 51 connects, for example, the fifth flow path 43E (injection rod side chamber 29r) and the pump 39 at the position shown on the left side of the drawing (hereinafter also referred to as “a position”). The six flow paths 43F (the injection head side chamber 29h and the small diameter cylinder part 33a) and the tank 37 are connected. Thereby, for example, the hydraulic fluid can be supplied from the pump 39 to the injection rod side chamber 29r, and the injection piston 31 can be moved backward.

  Here, in the illustrated example, the seventh flow path 43G that connects 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 supplying the hydraulic fluid 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 increasing piston 35 is obtained.

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

  In addition, 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 drawing (hereinafter also referred to as “b position”), and the sixth flow The path 43F (injection head side chamber 29h) and the pump 39 are connected. Thereby, the hydraulic fluid can be supplied from the pump 39 to the injection head side chamber 29h, and the injection piston 31 can be advanced. However, in this embodiment, the flow of the 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. In FIG. 2, the auxiliary valve 51 is shown as being closed by a spring at a normal position (position at the center of the paper) and controlled by sequentially operating electromagnetic force and pilot pressure.

  The valve 53 is, for example, a check valve provided in the first flow path 43A (part 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 the flow in the opposite direction is prohibited.

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

  In addition to the above, the hydraulic device 28 includes, for example, a filter 57 that filters the hydraulic fluid from the tank 37 to the pump 39, a cooler 59 that cools the hydraulic fluid that flows to the tank 37 via the speed valve 49, and the like. ing.

(Functional part and sensor of control device)
For example, although not particularly illustrated, the control device 13 is configured by a computer including a CPU, a RAM, a ROM, and an external storage device. When the CPU executes programs stored in the ROM and the external storage device, a plurality of functional units responsible for various controls or calculations 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 performs control for increasing the pressure in the injection rod side chamber 29r before the start of injection. The injection control unit 13b performs control for injecting the molding material into the mold 101 (for injection in a narrow sense). The pressure increase control unit 13 c performs control for increasing the pressure of the molding material injected into the mold 101 (for pressure increase).

  These functional units output control signals to the hydraulic device 28 based on signals from the input device 17 and various sensors, for example. 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 a scale portion (not shown) in a direction orthogonal to the axial direction of the scale portion, and generates a pulse in accordance with relative movement in the axial direction with respect to the scale portion. 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 accumulating the number of generated pulses, and specify the number of pulses per time. By doing so, the speed can be specified.

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

  Note that the position sensor 69 may output only a pulse, or may specify a position and / or 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 according to the position is output because the total number of pulses differs according to the position, and the signal according to the speed is different because the number of pulses per unit time differs according to the speed. 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 changes in position and / or velocity.

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

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

(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 changes over time in the injection speed V (advance speed of the plunger 23) and the injection pressure P (pressure applied by the plunger 23 to the molten metal). In the upper part of FIG. 4, the horizontal axis indicates the time t, and the vertical axis indicates the injection speed V and the injection pressure P. Lines L _V and L _P indicate changes in the injection speed V and the injection pressure P over time, respectively.

  The lower part of FIG. 4 shows the operations of the injection valve 45, the pressure increasing 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, a solid line indicates the operation in the present embodiment, and a two-dot chain line indicates a modified example described later. “Open” of the pressure increasing valve 47 and the speed valve 49 indicates a state in which these valves are opened and the opening degree is appropriately controlled. Note that the timing at which the control device 13 outputs the control signal may be set earlier than the timing shown in view of valve control delay or the like.

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

(Pressure before injection starts)
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-increasing piston 35 are located at the backward limit, for example. The plunger 23 is located behind the supply port 21a. The accumulator 41 has been filled up to a predetermined pressure, for example. As described above, the pump 39 may be always driven, or may be driven only when necessary. In the latter case, for example, the pump 39 is stopped. The injection valve 45 is closed by introducing pilot pressure. The pressure increasing valve 47, the speed valve 49, and the auxiliary valve 51 are in the closed position.

  And the control apparatus 13 will start the pressurization to the injection rod side chamber 29r, if predetermined pressurization start conditions are satisfy | filled. Specifically, for example, the control device 13 opens the pressure increasing valve 47 and sets the auxiliary valve 51 to the position a. 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 ejection head side chamber 29h are depressurized. As a result, as shown in FIG. 3B, the pressure-increasing piston 35 moves forward until the force received from the front and back is balanced (in another aspect, by the distance δ), and the pressure-increasing rod side chamber 33r and the pressure increasing rod side chamber 33r. The hydraulic fluid in the injection rod side chamber 29r that communicates with is compressed.

  The pressure P1 (FIG. 3B) in the injection rod side chamber 29r at this time is theoretically the pressure increase ratio S3 related to the injection rod side chamber 29r by the pressure increasing piston 35 to the pressure P0 of the accumulator 41 (FIG. 3B). The size is multiplied by / S4 (P0 × S3 / S4). The distance δ is determined by, for example, the pressure before pressurizing 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 example shown in the figure, the hydraulic fluid is supplied from the pump 39 to the space including the injection rod side chamber 29r through the auxiliary valve 51 at the position a. The distance δ can be smaller than if not.

  When the pressure is applied to the injection rod side chamber 29r, the small diameter cylinder part 33a and the injection head side chamber 29h are depressurized. Therefore, even if the pressure increasing piston 35 moves forward, the injection piston 31 does not move forward. That is, the plunger 23 does not advance.

  The pressurization start condition (pressurization start timing in another aspect) is such that the compression (pressurization) of the hydraulic fluid in the injection rod side chamber 29r by the pressure-increasing piston 35 is completed before the injection is started. It may be set appropriately so as to advance to some extent.

  The completion of compression or pressurization here means that, for example, the pressure before and after the pressure increasing piston 35 is balanced and the pressure increasing piston 35 is stopped, and from another viewpoint, the pressure P1 of the injection rod side chamber 29r is P0 × described above. S3 / S4 (strictly, slightly smaller than this due to the influence of sliding resistance, etc.) has been reached, and from another viewpoint, the amount of movement of the pressure increasing piston 35 has reached the distance δ. In the description of the present disclosure, for example, an operation of closing the pressure increasing valve 47 while the pressure in the injection rod side chamber 29r is increasing is referred to as stop or end of pressurization (compression). (Compression) is not said to be complete.

  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, generally, after completion of mold clamping, the molten metal is supplied to the sleeve 21 by a hot water supply device (not shown) and the plunger 23 starts to advance, 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 (clamping completion in the above example), or a predetermined time after such precondition has occurred.

(Low speed injection)
When a predetermined injection start condition is satisfied (time point t0), the control device 13 ends the pressurization to the injection rod side chamber 29r, starts to advance the plunger 23, and further, a relatively low speed low injection speed V. _The plunger 23 is advanced by _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-increasing valve 47 and stops supplying the hydraulic fluid from the accumulator 41 to the pressure-increasing head side chamber 33h. Thereby, the operation | movement (pressurization) which provides the pressure of the accumulator 41 to the injection rod side chamber 29r via the pressure increase piston 35 is complete | finished. For example, the control device 13 sets the auxiliary valve 51 to the 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. Thereby, preparation for the start of injection is made.

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

  At this time, as already described, the jumping is suppressed because the pressure in the injection rod side chamber 29r is increased in advance. For example, theoretically, if the area ratio S3 / S4 is greater than or equal to the area ratio S1 / S2, the plunger 23 does not advance (jumping does not occur).

  By supplying the hydraulic fluid from the accumulator 41 to the injection head side chamber 29h, the pressure increasing piston 35 is urged rearward. However, the pressure increasing valve 47 is closed, and the discharge of the hydraulic fluid from the pressure increasing head side chamber 33h is prohibited. Therefore, as shown in FIG. 3C, the pressure increasing piston 35 does not move backward, but the position advanced by the distance δ from the backward limit is maintained. Accordingly, for example, the volume of the small-diameter cylinder portion 33a increases due to the retraction of the pressure-increasing piston 35, and the possibility that the plunger 23 moves forward with respect to the supply of the hydraulic fluid to the injection head side chamber 29h is reduced. Is done. Since the pressure increasing valve 47 is a non-leak valve, the action of maintaining the position of the pressure increasing piston 35 is increased.

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

  The injection start condition may include that the pressurization to the injection rod side chamber 29r before the start of injection is completed in addition to the above-described preconditions being satisfied. Completion of pressurization may be determined, for example, based on whether or not a predetermined time has elapsed from the start of pressurization, or the injection rod side chamber 29r (the 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 in the path 43G) has reached a predetermined threshold value. In addition, for example, the determination can also be made by detecting the movement or position of the pressure increasing piston 35.

  In the above example, the pressurization start condition does not include a final one (for example, completion of hot water supply) of the general preconditions for starting the injection that does not perform pressurization to the injection rod side chamber 29r before the start of injection. It is set to be satisfied before the condition. In another aspect, the pressurization start condition is set such that there is no delay in the start of injection or the delay is reduced as compared to general injection without pressurization. However, the pressurization start condition includes a final precondition for starting injection, and the injection start condition may be, for example, that pressurization is completed.

  In the illustrated example, when the pressure increasing valve 47 and the auxiliary valve 51 are closed, the injection valve 45 and the speed valve 49 are opened almost simultaneously. However, even if the pressure increasing valve 47 and the auxiliary valve 51 are closed, the pressure in the injection rod side chamber 29r is theoretically maintained (unless liquid leakage is taken into consideration). There may be a time difference 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 need 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 injection, for example, it is facilitated to secure the time required for completion of pressurization before the start of injection (in another aspect, the pressurization start time is delayed), and In addition, the effect of pressurization due to liquid leakage does not occur.

  In the illustrated example, the injection valve 45 and the speed valve 49 are opened substantially simultaneously. However, after the injection valve 45 is opened, the speed valve 49 may be opened. In this case, for example, when the speed valve 49 is opened, the forward movement of the plunger 23 is started. That is, the injection start time is when the speed valve 49 is opened.

  The speed of the plunger 23 is controlled by controlling the opening degree of the speed valve 49, for example. 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 such that the deviation of the speed itself is obtained, or the deviation between the target position that is obtained from the target value of the speed (every elapsed time) and the detected position is obtained. The speed feedback control may be substantially performed by performing the position feedback control from moment to moment.

The low injection speed V _L may be set as appropriate, 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 unit 13 advances the plunger 23 at a relatively high speed of high-speed injection speed V _H. Thereby, for example, the molten metal is quickly filled into the cavity Ca without delaying the solidification of the molten metal. The high injection speed V _H may be set as appropriate, but is, for example, 3 m / s or more. The high-speed injection speed _VH 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 during low-speed injection because the injection speed is relatively high.

  For the operation as described above, specifically, for example, the control device 13 opens the speed valve 49 while continuing to supply the hydraulic fluid from the accumulator 41 to the injection head side chamber 29h following the low speed injection. Increase the degree. Thus, when only increasing the opening degree of the speed valve 49, the control device 13 performs, for example, open control or feedback control subsequent to the low speed injection, and simply sets the target speed value from the low speed injection to the high speed injection. All you need to do is change to

  For example, the control device 13 converts a target speed set for each section obtained by dividing the movement range of the plunger 23 into a plurality of target values of the position of the plunger 23 for each elapsed time, and position feedback control (substantially) Speed feedback control), and it is not detected whether the plunger 23 has reached the high speed switching position. However, the control device 13 may switch the target speed value by detecting that the plunger 23 has reached a predetermined high-speed switching position based on a signal from the position sensor 69.

(Deceleration)
As a result of the high-speed injection, when the molten metal is almost filled in the cavity Ca (time t2), the pressure of the molten metal rises, and thereby the plunger 23 decelerates. Note that deceleration control may be performed by reducing the opening of the speed valve 49 at an appropriate time. As a result of the deceleration, the plunger 23 substantially stops (time point t4).

(Intensification and holding pressure)
The control device 13 starts increasing pressure while the speed of the plunger 23 is being reduced as described above. Specifically, for example, the control device 13 opens the pressure-increasing valve 47 at an appropriate time (t3), and supplies hydraulic fluid from the accumulator 41 to the pressure-increasing head side chamber 33h. On the other hand, the pressure increasing rod side chamber 33r is allowed to discharge the hydraulic fluid to the tank 37 via the speed valve 49. Therefore, a pressure higher than the pressure in the pressure-increasing head side chamber 33h is applied to the injection head-side chamber 29h by the pressure-increasing piston 35, so that the pressure is increased. The injection valve 45 is self-closed 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 is closed at an appropriate time. Further, the control device 13 sets the opening degree of the speed valve 49 to an appropriate opening degree for increasing the pressure so that an appropriate boosting curve is obtained.

  The pressure in the pressure-increasing head side chamber 33h rises at the time of pressurization to the injection rod side chamber 29r before the start of injection, and thereafter is relatively high (for example, higher than the tank pressure) so as to prevent the pressure-increasing piston 35 from moving backward. ) 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 when the pressure increasing valve 47 is opened until the pressure in the pressure increasing head side chamber 33h increases. become.

  It should be noted that the output timing of the control command for increasing the opening degree of the speed valve 49 relative to the output timing of the control command for opening the pressure increasing valve 47 may be delayed, for example. Good. The output of a control command for opening the pressure increasing valve 47 can be started during high-speed injection.

  Thereafter, the injection pressure becomes constant (the casting pressure becomes constant) by the balance between the increased pressure due to the pressure in 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 in the injection rod side chamber 29r is, for example, a tank pressure (generally 0). In addition, 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. The casting pressure may be obtained. In the pressure holding process, the control device 13 maintains the state when the casting pressure is obtained. For example, the pressure increasing valve 47 and the speed valve 49 are left open.

(Plunger retreat, etc.)
When the molten metal filled in the cavity Ca is solidified, the control device 13 ends the holding pressure. Specifically, for example, the control device 13 closes the pressure increasing 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 shown in particular, when the mold is opened, the control device 13 may control the hydraulic device 28 so as to push the biscuit by the plunger 23 (to perform the extrusion follow-up).

  After starting mold opening or when performing extrusion follow-up, the control device 13 returns the injection device 9 to the initial state before the start of injection. Specifically, for example, the injection device 9 sets the auxiliary valve 51 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 is connected to the tank 37. The control device 13 also connects the pressure-increasing 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 increasing rod side chamber 33r, and the injection piston 31 and the pressure increasing piston 35 are moved backward. The hydraulic fluid in the ejection head side chamber 29h and the pressure increase head side chamber 33h is discharged to the tank 37. The hydraulic fluid discharged from the ejection head side chamber 29h and / or the pressure increase head side chamber 33h may be filled in the accumulator 41 instead of the tank 37.

  Although not particularly illustrated, after the injection piston 31 and the pressure increasing piston 35 reach the retreat limit, the control device 13 sets the auxiliary valve 51 to the neutral position, and in a mode in which the pump 39 is not continuously driven, the pump 39 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 backward movement of the plunger 23 is completed, the control device 13 drives the pump 39 with the injection valve 45, the pressure increasing 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 shown in particular, the hydraulic 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. Also good. For example, the auxiliary valve 51 is connected to the pump 39 and the sixth flow path 43F (injection head side chamber 29h) and the fifth flow path 43E (injection rod side chamber 29r) and the tank 37 are shut off at the position b. Configure.

  In the low-speed injection, the auxiliary valve 51 is set to the b position (see the two-dot chain line in the diagram related to the auxiliary valve 51 in FIG. 4), and the hydraulic fluid is supplied from the pump 39 to the injection head side chamber 29h. 31, the speed valve 49 controls the speed of the plunger 23 in the injection rod side chamber 29r. 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 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 increasing piston 35.

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

(Third Modification)
After the accumulator 41 is filled and before the pressure increasing valve 47 is opened to pressurize the injection rod side chamber 29r, the auxiliary valve 51 is set to the a position (the auxiliary valve 51 in FIG. The hydraulic pressure may be given 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 the pressurization is performed by the pressure increasing piston 35, and / or after the injection piston 31 and the pressure increasing piston 35 in the previous cycle are retracted, The pressure in the injection rod side chamber 29r, which has decreased due to liquid leakage or the like, can be recovered immediately before the pressurization by the pressure increasing piston 35. As a result, for example, the moving amount δ of the pressure increasing piston 35 can be shortened.

  As described above, in this embodiment, the injection device 9 includes the injection cylinder 27 that drives the plunger 23 that pushes the molding material into the front mold 101, and the hydraulic device 28 that controls the flow of hydraulic fluid in the injection cylinder 27. And a control device 13 for controlling the hydraulic 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 part of the injection piston rod 32. The injection cylinder part 29 accommodates the injection piston 31 so as to be slidable, and the inside thereof is partitioned by the injection piston 31 into a front injection rod side chamber 29r and a rear injection head side chamber 29h. The small diameter cylinder portion 33a communicates with the injection head side chamber 29h. The large-diameter cylinder portion 33b continues 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 accommodated in the small diameter cylinder portion 33a. The large-diameter piston 35b is fixed in series to the small-diameter piston 35a and is slidably accommodated in the large-diameter cylinder portion 33b. The inside of the large-diameter cylinder portion 33b is a pressure increasing rod side chamber 33r on the small-diameter cylinder portion 33a side. And a pressure increasing head side chamber 33h on the opposite side. The control device 13 supplies the hydraulic fluid to the pressure-increasing head side chamber 33h and starts controlling the hydraulic device 28 so as to apply the hydraulic pressure from the pressure-increasing rod side chamber 33r to the injection rod side chamber 29r before the injection is started. It has a portion 13a.

  Therefore, for example, as already described, it is possible to reduce the possibility of jumping occurring at the start of injection. At this time, 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 by the pressure increasing action of the pressure increasing piston 35. Further, for example, since the pressure increasing action is obtained by using the pressure increasing piston 35 for pressure increasing, it is not necessary to provide a pressure increasing cylinder separately from the injection cylinder 27. Compared to such an aspect, the injection device 9 Downsizing and / or cost reduction. The pressure increase of the pressure increasing rod side chamber 33r by the pressure increasing piston 35 at the pressurization (to t0) to the injection rod side chamber 29r is different from the pressure increase in the small diameter cylinder part 33a by the pressure increasing piston 35 at the pressure increase (t3). It is not directly connected to the boosting of the ejection head side chamber 29h. Therefore, for example, the advancement of the injection piston 31 can be suppressed while the pressure increasing piston 35 is advanced. The pressure-increasing action of the pressure-increasing piston 35 on the pressure-increasing rod side chamber 33r is not a normally used action, unlike the pressure-increasing action in the small-diameter cylinder portion 33a by the pressure-increasing piston 35 at the pressure increase (t3). The configuration of the present embodiment that can obtain the various effects described above by using 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 perform pressure relief of the injection head side chamber 29h when pressurizing the injection rod side chamber 29r before the start of injection.

  Therefore, the possibility that the injection piston 31 moves forward during pressurization can be reliably suppressed. As a result, for example, the relative relationship between the position and speed of the plunger 23 at the start of injection set by the operator can be realized with high accuracy.

  In the present embodiment, the injection cylinder 27 has a stopper 36 that is fixed to the injection cylinder portion 29 and restricts the backward movement of the injection piston 31.

  Therefore, even if the pressure in the injection rod side chamber 29r rises before the start of injection, the backward movement of the injection piston 31 is suppressed. Unlike the aspect in which the rod fixedly provided on the pressure increasing piston 35 is brought into contact with the rear end of the injection piston 31 to restrict the backward movement of the injection piston 31, the advance of the pressure increasing piston 35 before the start of injection is It does not directly connect to the advance of the injection piston 31.

  In the present embodiment, the small diameter cylinder portion 33 a continues in series with 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 a stopper 36 is constituted by a 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 part and to reduce the manufacturing cost of the cylinder part.

  In the present embodiment, the pressure receiving area S1 in 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 (S3 / S4) / (S1 / S2) of the area S3 to the pressure receiving area S4 in the pressure increasing rod side chamber 33r of the large diameter piston 35b is 0.9 or more and 1.2 or less.

  Therefore, for example, the pressure before the start of injection generated in the injection rod side chamber 29r by the pressure increasing action of the pressure increasing piston 35 is applied to the injection piston 31 when the working fluid is supplied from the accumulator 41 to the injection head side chamber 29h. It is easy to make the pressure equal to or greater 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, and the injection head is supplied with hydraulic fluid for injection When the pressure in the side chamber 29h is 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 at the pressure increase (t3) decreases, 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 control valve.

Second Embodiment
(Configuration of injection drive unit)
FIG. 5 is a schematic diagram illustrating a configuration of an 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 that combines a hydraulic type and an electric type. Corresponding to this difference, the operation (control by the control device 13) of the injection driving unit 225 of the present embodiment is also different from that of the first embodiment. In addition, the other structure of this embodiment is the same as that of 1st Embodiment.

  Specifically, the injection drive unit 225 includes 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 a coupling 24, for example. The coupling 24 includes, for example, a case member (not shown) that accommodates the rear end of the plunger 23 and the tip of the injection piston rod 32, and the case member is interposed between the plunger 23 and the injection piston rod 32. On the other hand, the part which expands is comprised.

  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 a 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, when the driving force is transmitted from the driven portion 291 to the plunger 23, the plunger 23 is driven.

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

  The drive motor 283 may be a DC motor or an AC motor, or may be 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 a servo motor, for example, and forms 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. Yes.

  The transmission mechanism 285 is constituted by, for example, a pulley / belt mechanism, and includes a first pulley 285a fixed to the output shaft 283a of the driving motor 283, a second pulley 285b fixed to the conversion mechanism 287, and a first pulley 285b. And a belt 285c spanning the pulley 285a and the 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 includes, for example, a ball screw mechanism, and includes a screw shaft 287a and a nut 287b that is screwed to the screw shaft 287a via a ball (not shown).

  The screw shaft 287a is disposed in parallel to the injection piston rod 32. The screw shaft 287a is restricted from moving in the axial direction and is allowed to rotate about the axis. 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 287 a is rotated, the nut 287 b moves in a direction parallel to the injection piston rod 32.

  The above-described 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 287 b moves in a direction parallel to the injection piston rod 32 by the driving force of the driving electric motor 283.

  The driven portion 291 is restricted from relative advancement relative to the injection piston rod 32 by engagement and / or attachment / detachment and the like, and is allowed to move backward relative to the injection piston rod 32. In addition, since the injection piston rod 32 and the plunger 23 are connected, the relative forward restriction and backward allowance with respect to the injection piston rod 32 referred to here are relative forward restriction and backward allowance with respect to the plunger 23. It is synonymous with.

  Specifically, for example, the driven portion 291 includes a base portion 291a, a hook 291b that is swingably supported by the base portion 291a, and an actuator (not shown) that drives the hook 291b.

  The base 291a is fixed to, for example, a nut 287b. Further, the base portion 291a can be in contact with the coupling 24 (contacted portion) from the rear, for example. Accordingly, the base portion 291a is restricted from moving forward relative to the injection piston rod 32 by contact with the coupling 24, and is allowed to move backward relative to the injection piston rod 32 from the contact position.

  Therefore, the plunger 23 can be advanced by advancing the base 291a in a state where the base 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. In addition, the plunger 23 can be moved forward relative to the base 291a by supplying hydraulic fluid to the injection head side chamber 29h and moving the injection piston rod 32 at a relatively high speed.

  For example, the hook 291b is formed in an approximately L shape, and one end thereof is rotatably supported by the base portion 291a. The hook 291b has a position where it can be engaged with the coupling 24 (contacted portion, engaged portion) in the retracting direction of the plunger 23 (a position shown in the figure), and a position where the engagement is released ( It is possible to move between the position shown in FIG. The hook 291b can clamp the coupling 24 with the base 291a at the engagement position.

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

  An actuator (not shown) for driving the hook 291b may be realized by an appropriate one such as an air cylinder or a linear motor. Note that the hook 291b and the actuator need not be provided. In addition to or instead of the engagement of the base portion 291a, the driven portion 291 is attached to and detached from the injection piston rod 32 with an electromagnet, or is attached and detached by pinching in the radial direction of the injection piston rod 32 (and hence frictional resistance). It may be done.

  Although not particularly illustrated, the injection drive unit 225 may have a pair of electric drive units 281 that are left-right symmetric or vertically symmetric. The pair of electric drive units 281 may share one drive 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. Contrary to the illustrated example, the nut 287b cannot move in the axial direction and can rotate about the axis, the screw shaft 287a can move in the axial direction and cannot rotate about the axis, and the driven part 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, schematically showing the configuration of the hydraulic system of the injection driving 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, a ninth flow path 243I and a 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 the 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 channel 243I (portion not shared with other channels (43D, 43E, 43G, and 43H)). The relief valve 293 allows the hydraulic fluid to flow from the injection rod side chamber 29r to the tank 37 when the pressure in the injection rod side chamber 29r exceeds a predetermined set pressure. Thereby, the pressure of the injection rod side chamber 29r is maintained below a predetermined set pressure. The relief valve 293 may be such that the pressure in the injection rod side chamber 29r directly acts on the valve body, or the pressure in the injection rod side chamber 29r may be used as a pilot pressure. Further, the relief valve 293 may be one in which the set pressure is manually adjusted, or may be adjusted by a solenoid or the like.

  The set pressure of the relief valve 293 may be set as appropriate. For example, when 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 assumed to be a flow rate for high speed injection, the injection is performed. The pressure may be approximately the same as the pressure generated in the rod side chamber 29r. Further, the pressure may be higher or 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, the pressurization control unit 13a, the injection control unit 13b, and the pressure increase control unit 13c are constructed as in the first embodiment. In more detail, the signals input to each function unit, the calculation of each function unit, and the output destination of the control signal of each function unit are different from those in the first embodiment, but for convenience, the same as in the first embodiment. Is attached to each functional part.

  A device that inputs a signal to the control device 13 is different from that of the first embodiment, for example, is an encoder 283b. Further, as the device from which the control device 13 outputs a signal, what is different from the first embodiment is, for example, a driving motor 283 (driver thereof) and an actuator (not shown) that drives the hook 291b.

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

  The horizontal and vertical axes in FIG. 7 are the same as those in FIG. However, in FIG. 7, in addition to the control target shown in FIG. 4, a drive motor 283 is added.

  The injection device 209 is, for example, similar to the first embodiment, the pressure applied to the injection rod side chamber 29r (˜time t0), low speed injection (approximately time t0 to t1), high speed injection (approximately time t1 to t2), and The pressure increase (pressure increase, approximately time points t3 to 3) is sequentially performed. Specifically, it is as follows.

(Pressure before injection starts)
Before the pressurization is started, the state of the hydraulic system of the injection device 209 is the same as, for example, the state before the pressurization is started in the first embodiment. In addition, before the pressurization is started, the base 291a of the electric drive unit 281 is engaged, for example, from the rear with the injection piston rod 32 located in the retreat limit, and the hook 291b is in the engagement position. .

  And the control apparatus 13 performs the pressurization to the injection rod side chamber 29r similarly to 1st Embodiment. However, in the present embodiment, since the relief valve 293 is provided, the pressure in 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 the suppression of the forward movement of the injection piston 31 by its inertia, position control, brake (when equipped with a brake), or the like.

(Low speed injection)
As in 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 drive 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. Thereby, the plunger 23 and the injection piston rod 32 move forward.

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

  The supply of the hydraulic fluid to the injection head side chamber 29h whose volume increases as the injection piston 31 moves forward may be performed as appropriate. For example, the auxiliary valve 51 may be set to the position a to connect the injection head side chamber 29h and the tank 37 (the pump 39 is stopped, for example), and the hydraulic fluid may be replenished with a negative pressure. Further, for example, the hydraulic fluid may be replenished from the pump 39 to the ejection head side chamber 29h by the configuration described in the first modification. At this time, the pressure of the hydraulic fluid in the ejection head side chamber 29h may be set so as not to generate a negative pressure, or may be set to a pressure 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 number of rotations of the drive motor 283. Specifically, the control device 13 feedback-controls the rotational speed of the drive motor 283 based on a signal from the position sensor 69. Note that this speed feedback control may be performed with the speed itself as a deviation, or may be position feedback control from moment to moment, as in the first embodiment.

  In the low-speed injection, the hook 291b may be engaged with the coupling 24 or may not be engaged. When engaged, for example, when multistage control including deceleration is performed, the possibility that the plunger 23 moves away from the base portion 291a due to inertial force can be reduced.

(High speed injection)
High-speed injection is performed in the same manner as in the first embodiment. That is, the injection valve 45 is opened to supply 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. The The speed of the plunger 23 is controlled by the flow rate in the speed valve 49 and is feedback controlled based on a 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 a valve (not shown) provided in the ninth flow path 243I.

  In the high-speed injection, the hook 291b is at a position where the engagement is released. Accordingly, the plunger 23 driven by the injection cylinder 27 moves forward leaving the driven portion 291 away. Thereby, the electric drive unit 281 does not become a load that prevents the plunger 23 from moving forward.

  FIG. 7 illustrates a case where the driving 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. Subsequently, the driven portion 291 may be advanced.

(Deceleration, pressure increase, holding pressure, extrusion follow-up and plunger retraction)
Deceleration, pressure increase, pressure keeping, extrusion follow-up, and plunger retraction may be performed in the same manner as in the first embodiment. However, following the low-speed injection, the driven portion 291 is advanced, the driven portion 291 is caused to catch up with the plunger 23 decelerated by the force from the molten metal, etc., and the electric drive portion 281 is increased in pressure, held pressure, and extruded following. You may make it contribute to either. Alternatively, 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 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 by the hydraulic device, and the speed valve 49 can be fully opened at the time of the speed control by the electric motor. Therefore, compared with the first embodiment, the possibility of jumping is low. And jumping can be more reliably suppressed by the pressurization to the injection rod side chamber 29r before the start of injection.

  Further, when the injection piston 31 is moved forward 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 in the injection rod side chamber 29r is basically constant (set pressure) after the start of low speed injection. 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 in the injection rod side chamber 29r increases as the low-speed injection proceeds and converges to a constant (set pressure).

  Therefore, the pressure fluctuation in the injection rod side chamber 29r is suppressed while the plunger 23 is driven by the electric drive unit 281 by the pre-injection pressurization and the relief valve 293. 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 is possible.

  In the present embodiment, since a relatively high hydraulic pressure is applied to the ejection head side chamber 29h at the start of high-speed injection, jumping may occur at this time. However, since the pressure in 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 less than in the mode in which the pressure in the injection rod side chamber 29r is the tank pressure in the low speed injection. The risk of occurrence is reduced.

  Also in this embodiment, the second modification and the third modification may be applied.

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

  In the first and second embodiments, basically, the pressure increasing valve 47 is opened only when the pressure increasing piston 35 is driven (in other words, only when pressure is applied to the injection rod side chamber 29r and pressure is increased). A 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 increasing rod side chamber 33r, the driving of the pressure increasing piston 35 is controlled (pressure increase and pressure increase 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, the hydraulic mode is taken as an example.

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

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

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

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

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

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

  The pressurizing valve 483 is constituted by, 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 pressure increasing rod side chamber 33r to the injection rod side chamber 29r and prohibits the flow in the opposite direction. When is introduced, both flows are prohibited.

  Other configurations of the hydraulic device 428 may be the same as those of the hydraulic device 28 of the first embodiment. In FIG. 9, pressure sensors 73 and 75 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 ejection 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 units described in the first embodiment, the control device 13 includes, for example, a head controller 13d that controls the 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 corresponds to FIG. 4 of the first embodiment.

  The horizontal and vertical axes in FIG. 10 are the same as those in FIG. However, FIG. 10 shows the operation of the pressure-increasing head valve 447 instead of the operation of the pressure-increasing valve 47. Further, operations of the pressurizing valve 483 and the pressure increasing rod valve 481 are added.

  The injection device 409, for example, as in the first embodiment, applies pressure to the injection rod side chamber 29r (up to time t0), low speed injection (about time t0 to t1), high speed injection (about time t1 to t2), and The pressure increase (pressure increase, approximately time points t3 to 3) is sequentially performed. Specifically, it is as follows.

(Pressure before injection starts)
Prior to the start of pressurization, the state of the injection device 409 is basically the same as in the first embodiment. Further, the pressure-increasing head valve 447, the pressure-increasing valve 483, and the pressure-increasing rod valve 481, which are not provided in the first embodiment, are closed, for example.

  When the pressurization start condition described in the first embodiment is satisfied, the control device 13 opens the pressure-increasing head valve 447, opens the pressurization valve 483, and sets the auxiliary valve 51 to the position a. As a result, as in the first embodiment, the injection rod side chamber 29r is pressurized before the start of injection. In the illustrated example, the timing of the three valves is illustrated at the same time. However, these timings are appropriately changed, such as opening the pressure increasing head valve 447 before or after the other valves. 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 the hydraulic pressure from the pressure increasing rod side chamber 33r to the injection rod side chamber 29r. For example, the control device 13 sets the auxiliary valve 51 to the 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. Thereby, preparation for the start of injection is made.

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

  Thereafter, 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 increasing 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 maintained in a closed state, for example.

(Intensification and holding pressure)
The injection device 409 starts pressure increase when a predetermined pressure increase start condition is satisfied (t3). The increase start condition may be set as appropriate.

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

  Moreover, when the molten metal is filled in the cavity Ca, the plunger 23 is decelerated by the force received from the molten metal in the cavity Ca. Accordingly, the pressure increase start condition may be that the injection speed has decreased to a predetermined pressure increase start speed. The injection speed used to determine whether or not the pressure has increased to the pressure increase start speed is obtained based on the detection value of the position sensor 69, for example.

  Further, as the molten metal is filled into the cavity Ca, the injection pressure (for example, the pressure that the plunger 23 applies to the molten metal) increases. Therefore, the pressure increase start condition may be that the injection pressure has increased to a predetermined pressure increase start pressure. The injection pressure used to determine whether or not the pressure has increased to the pressure increase start pressure is obtained based on the detection values of the pressure sensors 73 and 75, for example.

  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. .

  For example, the control device 13 opens the pressure-increasing rod valve 481 to start pressure increase. As a result, the pressure-increasing piston 35 is allowed to advance, and a pressure increased higher than the pressure in the pressure-increasing head side chamber 33h is applied to the ejection head side chamber 29h.

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

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

  After that, as in the first embodiment, the injection pressure becomes constant (the casting pressure becomes constant) by the balance between the pressure caused by the pressure of the increased injection head side chamber 29h and the force caused by the pressure received by the plunger 23 from the molten metal. .) At this time, the pressure in the injection rod side chamber 29r and the pressure in the pressure increasing rod side chamber 33r are, for example, tank pressure. An 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 process, the control device 13 maintains the state when the casting pressure is obtained. When the pressure holding process ends, 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 in the first embodiment.

  As described above, also in the present embodiment, the injection device 409 supplies the hydraulic pressure to the pressure increasing rod side chamber 33r from the pressure increasing rod side chamber 33r and applies the hydraulic pressure to the injection rod side chamber 29r before the start of injection. Accordingly, the same effects as those of the first and second embodiments can be obtained. For example, the possibility of jumping occurring at the start of injection can be reduced.

  In this embodiment, the hydraulic pressure device 428 includes an accumulator 41 that supplies hydraulic fluid to the pressure-increasing head side chamber 33h, and a pressure-increasing rod valve 481 that controls the flow rate of hydraulic fluid discharged from the pressure-increasing rod side chamber 33r. And have. The control device 13 controls the hydraulic pressure device 428 so that the hydraulic fluid is continuously supplied from the accumulator 41 to the pressure increasing head side chamber 33h from (at least) pressurization to the injection rod side chamber 29r to completion of pressure increase. 13d and a pressure increase control unit 13c that controls the hydraulic pressure device 418 so as to start the pressure increase by opening the pressure increasing 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 from when the control device 13 outputs a command to open the pressure increasing valve 47 to when the pressure increasing piston 35 actually moves forward. As a result, there is a possibility that pressure increase cannot be started at a suitable timing. The reason is, for example, that it takes time until the hydraulic fluid from the pressure increasing valve 47 to the pressure increasing head side chamber 33h is compressed.

  However, in the present embodiment, such a problem does not occur because the hydraulic pressure is applied to the pressure-increasing head side chamber 33h before the start of pressure increase. Note that, in FIG. 10, the effect is expressed by showing the step-up curve from time t <b> 3 to t <b> 4 sharply as compared to FIGS. 4 and 7.

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

  However, in this case, various disadvantages also occur. For example, since the pressure increasing piston 35 is advanced before the start of pressure increasing, the stroke of the pressure increasing piston 35 becomes long. Further, when the pressure-increasing piston 35 starts to advance before the start of pressure-increasing (before the completion of injection in a narrow sense), the pressure in the injection head side chamber 29h is increased by the pressure-increasing action, and the accumulator 41 passes through the injection valve 45. As a result, the flow rate of the working fluid flowing to the ejection head side chamber 29h decreases. As a result, unintended deceleration is performed in the narrowly defined injection. Further, the timing for opening the pressure increasing valve 47 must be set for each mold.

  However, in the present embodiment, the liquid from the accumulator 41 to the pressure-increasing head side chamber 33h in advance is controlled in a state where the advancement and pressure-increasing action of the pressure-increasing piston 35 is 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-increasing head side chamber 33h in advance without causing the inconvenience of opening the pressure-increasing valve 47 before starting the pressure increase as described above.

  In the first or second embodiment, both the speed control in the narrow sense injection and the pressure control in the pressure increase are performed by the flow rate control 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 characteristic may be deteriorated. 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. For example, when the target value of the injection speed is changed, it is necessary to correct timing for switching from speed control to pressure control. In addition, the control accuracy may be reduced.

  However, in this embodiment, pressure control is performed by controlling the flow rate of the hydraulic fluid discharged from the pressure increasing rod side chamber 33r. In another aspect, the flow rate control for speed control and the flow rate control for pressure control are performed separately. As a result, the above inconvenience is solved. For example, the boosting characteristic is improved. Due to the improvement of the pressurization characteristics, for example, casting of a thin die cast product that is quickly cooled is facilitated.

  Also, if there is a variation in the amount of hot water supply between a plurality of shots, the relative relationship between the position of the plunger 23 and the progress of the filling of the molten metal will vary, and as a result, the quality of the die cast product will vary. However, in this embodiment, by starting the pressure increase based on the pressure increase start speed and / or the pressure increase start pressure, it is possible to start the pressure increase at an appropriate timing even if the hot water supply amount varies. Therefore, combined with the improvement of the boosting characteristic, a high-quality die cast product can be stably produced.

  In addition, compared with this embodiment, the first and second embodiments have an effect that, for example, only one flow control valve is required, and the cost can be reduced. Accordingly, any one of the first to third embodiments may be appropriately selected according to the specifications required by the user.

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

<Modification of cylinder part>
FIG. 8A and FIG. 8B show a modification of the cylinder part. In addition, although the following cylinder parts may be applied to any of 1st-3rd embodiment, the code | symbol etc. of 1st Embodiment are used in the following description. In addition, even if there is a difference from the first embodiment, the same reference numerals as those in the first embodiment are given to configurations in which the difference is mainly a dimension.

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

  And the stopper 303 which prescribes | regulates the retreat limit of the injection piston 31 is comprised by the convex part which protrudes from the inner surface of the injection cylinder part 29, and the inner surface of the small diameter cylinder part 33a. For example, the convex portion extends over the entire circumference of the inner peripheral surface of the injection cylinder portion 29 (is formed in an annular shape).

  Thus, the inner diameter d4 may not be smaller than the inner diameter d1. Moreover, from another viewpoint, the stopper is not limited to one constituted by a step on the inner surface between the cylinder chambers. Although not particularly illustrated, the inner diameter d4 may be larger than the inner diameter d1.

  In FIG. 8A, as a method of configuring the stopper 303, a member having a cylindrical portion that fits to the inner surface of the injection cylinder portion 29 and a flange portion that protrudes outward from the cylindrical portion is an injection cylinder portion. The case where it interposes between 29 and the small diameter cylinder part 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 positions thereof may be set as appropriate.

(5th modification)
In the embodiment, the pressure increasing cylinder part 33 is provided so as to be connected in series (for example, coaxially) to the injection cylinder part 29. On the other hand, in the injection cylinder 311 shown in FIG. 8B, the pressure increasing cylinder portion 33 is provided so as to intersect (for example, orthogonally cross) the injection cylinder portion 29.

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

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

  The molding machine is not limited to a die casting machine. For example, the molding machine may be another metal molding machine, an injection molding machine that molds a resin, or a molding machine that molds a material in which a thermoplastic resin or the like is mixed with wood flour. There may be. The molding material is not limited to a liquid material and may have a certain degree of viscosity. For example, the metal material may be a solid-liquid coexisting metal (semi-solid or semi-molten metal).

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

  The configuration 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 compound type using separate drive sources for mold opening and closing and mold clamping. Further, for example, the mold clamping device may be an all-electric type or an all-hydraulic type.

  In the case where the injection cylinder part and the pressure increasing cylinder part are connected in series, both may be eccentric. Moreover, the small diameter cylinder part and the large diameter cylinder part may be eccentric.

  The hydraulic circuit shown in the embodiment is merely an example, and the flow path and the valve may be appropriately set. For example, in the embodiment, the connection and disconnection with the tank and / or pump of the pressure increasing rod side chamber are completely shared with the connection and disconnection with the tank and / or pump of the injection rod side chamber, but can be controlled separately. A flow path and a valve may be provided. A valve may be provided in a flow path that connects the pressure increasing rod side chamber and the injection rod side chamber.

  In the 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 device may have a meter-in circuit in addition to the meter-out circuit.

  The hydraulic pressure source for supplying the hydraulic fluid to the pressure increasing head side chamber for pressurization to the injection rod side chamber before the start of injection is not limited to an accumulator, and may be a pump, for example. In another aspect, the hydraulic pressure source that supplies the hydraulic fluid to the pressure increasing 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, they may not be the same, and 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 increasing pressure and / or holding pressure. In the embodiment, the accumulator 41 is used for both injection and pressure increase. However, an accumulator for injection and an accumulator for pressure increase may be provided.

  The pressurization to the injection rod side chamber before the start of injection may be started at an appropriate timing after the retraction of the booster piston in the previous cycle, and as mentioned in the description of the embodiment, until the injection starts. There is no need to continue. The pressure in the injection rod side chamber at the start of injection (for example, when the speed valve 49 is opened or when the driving electric motor 283 is driven) is compared with the case where it is assumed that the pre-injection pressurization has not been performed. It only needs to be a little higher. In other words, after the pressure-increasing piston in the previous cycle is retracted, the hydraulic fluid is supplied to the pressure-increasing head side chamber, and the hydraulic pressure in the pressure-increasing rod side chamber is applied to the injection rod side chamber. If the pressure in the injection rod side chamber is somewhat higher than when it is assumed that the above operation was not performed at the start, it can be said that the pre-injection pressurization was 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 in order to solve the problem does not assume a meter-out circuit and may not be used for the purpose of suppressing jumping. For example, as understood from the low-speed injection operation of the second embodiment, in a state where the meter-out circuit is not functioning and a relief valve is provided, the application to the injection rod side chamber before the start of injection is performed. The pressure contributes to improving the control of the position and speed of the plunger by the electric motor while keeping the pressure fluctuation in the injection rod side chamber constant.

In addition, from the second embodiment, it is possible to extract the following injection devices that do not require the pre-injection pressurization.
An injection piston rod connected to a rear portion of a plunger for extruding a molding material into a front mold, an injection piston fixed to the rear portion of the injection piston rod, and an injection cylinder slidably containing the injection piston An injection cylinder in which the inside of the injection cylinder section is partitioned into a front injection rod side chamber and a rear injection head side chamber;
A hydraulic device capable of supplying hydraulic fluid to the ejection head side chamber;
An electric drive unit capable of driving the injection piston rod with respect to the injection cylinder unit;
Have
The hydraulic device has a relief valve that discharges hydraulic fluid from the injection rod side chamber when the pressure in the injection rod side chamber exceeds a predetermined pressure.

  In the above-described injection device, for example, if the discharge of the hydraulic fluid from the injection rod side chamber is allowed only from the relief valve during low-speed injection without performing pressurization before the start of injection, the high-speed injection is started. 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 addition, in the injection device that starts the pressure increase by opening the pressure increase side flow control valve while supplying the hydraulic fluid continuously to the pressure increase head side chamber extracted from the third embodiment, for example, a pressure increase curve The effect which can be improved is show | played. Further, in the above-described injection device, “before the pressure increase” is not limited to the narrow start before the injection (for example, before the low-speed injection) unlike the third embodiment, but after the narrow injection is started. It may be after the high speed injection is started. However, it is preferable that the application of the hydraulic pressure from the accumulator to the pressure increasing head side chamber is started at the timing when the compression of the hydraulic fluid in the pressure increasing head side chamber is completed before the pressure increase starts.

DESCRIPTION OF SYMBOLS 1 ... Die casting machine, 9 ... Injection apparatus, 13 ... Control apparatus, 13a ... Pressurization control part, 21 ... Sleeve, 23 ... Plunger, 27 ... Injection cylinder, 28 ... Hydraulic pressure apparatus, 29 ... Injection cylinder part, 29r ... Injection Rod side chamber, 29h ... Injection head side chamber, 31 ... Injection piston, 32 ... Injection piston rod, 33 ... Pressure increase cylinder part, 33a ... Small diameter cylinder part, 33b ... Large diameter cylinder part, 33r ... Pressure increase rod side chamber, 33h ... Increase Pressure head side chamber, 35 ... pressure increasing piston, 35a ... small diameter piston, 35b ... large diameter piston, 101 ... mold.

Claims (12)

An injection cylinder that drives a plunger that pushes the molding material into the front mold;
A hydraulic device for controlling the flow of hydraulic fluid in the injection cylinder;
A control device for controlling the hydraulic device;
Have
The injection cylinder is
An injection piston rod coupled to the rear of the plunger;
An injection piston fixed to a rear portion of the injection piston rod;
An injection cylinder portion that slidably accommodates the injection piston, and an inside is divided into a front injection rod side chamber and a rear injection head side chamber by the injection piston,
A small diameter cylinder portion communicating with the ejection head side chamber;
A large-diameter cylinder portion that continues in series with the small-diameter cylinder portion and has a larger diameter than the small-diameter cylinder portion;
A small-diameter piston slidably accommodated in the small-diameter cylinder portion;
The small-diameter piston is fixed in series, and is slidably accommodated in the large-diameter cylinder part. Inside the large-diameter cylinder part, the pressure-increasing rod side chamber on the small-diameter cylinder part side and the pressure-increasing side on the opposite side A large-diameter piston partitioned into a head side chamber,
The control device controls the hydraulic pressure device so as to supply hydraulic fluid to the pressure-increasing head side chamber and to apply a hydraulic pressure from the pressure-increasing rod side chamber to the injection rod side chamber before the start of injection. An injection device having a pressurizing control unit. The injection device according to claim 1, wherein the pressurization control unit controls the hydraulic pressure device so as to perform pressure relief of the ejection head side chamber during the pressurization. The injection device according to claim 1, wherein the injection cylinder has a stopper that is fixed to the injection cylinder portion and restricts the reverse movement of the injection piston. The small diameter cylinder part continues in series with the rear side of the injection cylinder part,
The inner diameter of the small diameter cylinder part is smaller than the inner diameter of the injection cylinder part,
The injection device according to claim 3, wherein the stopper is constituted by a step between the injection cylinder portion and the small diameter cylinder portion. The pressure receiving area S3 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 in 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 device has a flow rate control valve for controlling the flow rate of the hydraulic fluid discharged from the injection rod side chamber,
The controller is
An injection control unit for supplying hydraulic fluid to the injection head side chamber and controlling the hydraulic device to start injection by opening the flow control valve;
The pressure increase control part which controls the said hydraulic pressure device so that a pressure increase may be performed by supplying a hydraulic fluid to the said pressure increase head side chamber, The one of Claims 1-5. Injection device. An electric drive unit capable of driving the injection piston rod with respect to the injection cylinder unit;
The hydraulic device is
A relief valve that discharges hydraulic fluid from the injection rod side chamber when the pressure of the injection rod side chamber exceeds a predetermined pressure;
A flow rate control valve for controlling the flow rate of the hydraulic fluid discharged from the injection rod side chamber,
The controller 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 side chamber and the flow rate control valve is opened to perform high-speed injection at a speed higher than the low-speed injection. An electric drive unit and an injection control unit for controlling the hydraulic device;
The pressure increase control part which controls the said hydraulic pressure device so that a pressure increase may be performed by supplying a hydraulic fluid to the said pressure increase head side chamber, The one of Claims 1-5. Injection device. The hydraulic device is
An accumulator for supplying hydraulic fluid to the pressure-increasing head side chamber;
A pressure increasing side flow rate control valve for controlling the flow rate of the hydraulic fluid discharged from the pressure increasing rod side chamber,
The controller is
A head controller that controls the hydraulic device so as to supply hydraulic fluid from the accumulator to the pressure-increasing head side chamber continuously from the pressurization to the completion of the pressure increase;
The injection device according to any one of claims 1 to 7, further comprising: a pressure increase control unit that controls the hydraulic pressure device to start pressure increase by opening the pressure increase side flow control valve. . An injection cylinder that drives a plunger that pushes the molding material into the front mold;
A hydraulic device for controlling the flow of hydraulic fluid in the injection cylinder;
A control device for controlling the hydraulic device;
Have
The injection cylinder is
An injection piston rod coupled to the rear of the plunger;
An injection piston fixed to a rear portion of the injection piston rod;
An injection cylinder portion that slidably accommodates the injection piston, and an inside is divided into a front injection rod side chamber and a rear injection head side chamber by the injection piston,
A small diameter cylinder portion communicating with the ejection head side chamber;
A large-diameter cylinder portion that continues in series with the small-diameter cylinder portion and has a larger diameter than the small-diameter cylinder portion;
A small-diameter piston slidably accommodated in the small-diameter cylinder portion;
The small-diameter piston is fixed in series, and is slidably accommodated in the large-diameter cylinder part. Inside the large-diameter cylinder part, the pressure-increasing rod side chamber on the small-diameter cylinder part side and the pressure-increasing side on the opposite side A large-diameter piston partitioned into a head side chamber,
The hydraulic device is
An accumulator for supplying hydraulic fluid to the pressure-increasing head side chamber;
A pressure increasing side flow rate control valve for controlling the flow rate of the hydraulic fluid discharged from the pressure increasing rod side chamber,
The controller is
A head controller that controls the hydraulic device so as to supply hydraulic fluid from the accumulator to the pressure-increasing head side chamber continuously from before the start of pressure increase until completion of pressure increase;
A pressure increase control unit that controls the hydraulic pressure device to start pressure increase by opening the pressure increase side flow control valve; The hydraulic device has a pressurizing valve capable of allowing and prohibiting the flow of hydraulic fluid from the pressure increasing rod side chamber to the injection rod side chamber,
The said control apparatus has a pressurization control part which controls the said valve for pressurization so that a hydraulic pressure may be given to the said injection rod side chamber from the said pressure increase rod side chamber before the injection start. Injection device. The hydraulic device has a flow rate control valve for controlling the flow rate of the hydraulic fluid discharged from the injection rod side chamber,
The injection device according to claim 9 or 10, wherein the pressure increase control unit controls the hydraulic pressure device to fully open the flow rate control valve over pressure increase. The injection device according to any one of claims 1 to 11,
A mold clamping device for clamping the mold;
An extrusion device for extruding a molded product from the mold;
Having a molding machine.

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