JP6914120B2 - Injection device, molding machine and degassing device - Google Patents

Description

The present disclosure relates to an injection device that injects a molding material into a mold, a molding machine provided with the injection device, and a degassing device that can be used in the injection device. The molding machine is, for example, a die casting machine or a plastic injection molding machine.

An injection device that injects a molding material into a mold is known. For example, gas (for example, air) exists in the mold before injection. As the molding material is filled in the mold, the gas is discharged from an exhaust flow path (air vent) communicating with the inside and outside of the mold. If this discharge (venting of gas) is not optimized, for example, gas is entrained by the molding material, and the quality of the molded product is deteriorated.

Patent Document 1 discloses a technique in which air is ejected from an intermediate position of an exhaust flow path toward an outlet of the exhaust flow path to reduce the pressure on the outlet side of the exhaust flow path, thereby facilitating exhaust gas. .. Patent Document 2 discloses a technique of evacuating a vacuum tank by a driving force of an injection cylinder that generates a driving force for pushing out a molding material in an injection device that evacuates the inside of a mold by a vacuum tank.

Japanese Unexamined Patent Publication No. 10-328805 Jikkenhei 1-151953

Patent Document 1 does not pay attention to the property of a gas as a compressible fluid. As a result, there is a risk that the gas will not be sufficiently degassed even though air is being blown out. Therefore, it is desired to provide an injection device capable of degassing the mold, a molding machine including the injection device, and a degassing device that can be used for the injection device.

The injection device according to one aspect of the present disclosure includes a drive unit for driving a plunger in a sleeve leading to a cavity of a mold, an exhaust flow path for communicating the cavity with the outside of the mold, and an exhaust flow path.
The exhaust flow path has a throat portion that minimizes the cross-sectional area of a part of the flow path, and further, a portion outside the throat portion in a direction orthogonal to the exhaust flow path or the exhaust gas. When a gas is supplied to a decompression flow path that opens toward the downstream side of the flow path and one end of the decompression flow path, and the drive unit moves the plunger to the mold side. The throat portion has a gas supply portion that causes a sound velocity flow.

In one example, the exhaust flow path has a divergent portion having a larger cross-sectional area from the throat portion toward the outer side of the mold. In this example, the decompression flow path may be opened at the wide end.

In one example, the injection device has at least two decompression channels.

In one example, the two decompression flow paths are offset in at least one of the flow path direction of the exhaust flow path and the direction orthogonal to the flow path direction.

In one example, the injection device includes a drive control unit that controls low-speed injection and high-speed injection of the drive unit, and a gas from the gas supply unit to the decompression flow path only during the low-speed injection of the low-speed injection and the high-speed injection. It further has a decompression control unit that controls the gas supply unit so as to supply the gas.

In one example, the injection device includes an internal pressure sensor that detects the pressure inside the mold from the throat portion and an external pressure sensor that detects the pressure at any position from the throat portion to the outside of the mold. The ratio P _OUT / P _IN of the pressure sensor and the pressure P _{OUT detected by the external pressure sensor to the pressure PIN} detected by the internal pressure sensor is equal to or less than the value when a sound velocity flow occurs in the throat portion. It also has a decompression control unit that controls the gas supply unit.

In one example, the gas supply unit has a compressor in which a driving force for driving the plunger of the driving unit is transmitted to compress the gas.

In one example, the compressor includes a cylinder portion, a piston housed in the cylinder portion, and a piston that divides the inside of the cylinder portion into two cylinder chambers, and extends from the piston to the outside of the cylinder portion. It has a piston rod connected to the plunger, and the gas supply unit can control the connection and disconnection of the tank leading to the decompression flow path and the tank and the two cylinder chambers. It also has a cylinder.

In one example, the gas supply unit has a connection mechanism capable of allowing and prohibiting the transmission of a driving force from the driving unit to the compressor.

In one example, in the injection device, a drive control unit that controls low-speed injection and high-speed injection of the drive unit, and a driving force is transmitted from the drive unit to the compressor only at the time of low-speed injection of the low-speed injection and the high-speed injection. Further, it has a connection control unit that controls the connection mechanism.

The molding machine according to one aspect of the present disclosure includes the above-mentioned injection device and a mold-clamping device for molding the mold.

The degassing device according to one aspect of the present disclosure includes a throat portion leading to a cavity of the mold and a divergent portion having a larger cross-sectional area from the throat portion toward the outer side of the mold. an exhaust passage, a direction orthogonal to the exhaust passage, or a pressure reducing channel which opens Te in the divergent portion toward the downstream side of the exhaust passage, the gas to one end of the pressure reducing channel It has a gas supply unit that supplies and causes a sound velocity flow in the throat unit when the plunger in the sleeve leading to the cavity of the mold is moved to the mold side. The throat portion is a portion of the exhaust flow path where the cross-sectional area is minimized.

According to the above configuration, the degassing in the mold can be preferably performed.

The schematic diagram which shows the main part structure of the die casting machine which has the injection apparatus which concerns on embodiment of this disclosure. FIG. 6 is a schematic cross-sectional view showing a main configuration of the injection device of FIG. FIG. 3A is a cross-sectional view of the external block of the injection device of FIG. 1, and FIG. 3B is a plan view of the external block. The block diagram which shows the structure of the signal processing system of the injection apparatus of FIG. The figure for demonstrating the operation of the injection apparatus of FIG. 6 (a) to 6 (c) are schematic views for explaining the flow in and around the throat portion. 7 (a) and 7 (b) are cross-sectional views showing an exhaust flow path according to a modified example, respectively. 8 (a) to 8 (d) are schematic views showing the main configuration of the injection device according to the modified example.

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

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

The mold 101 includes, for example, a fixed mold 103 and a moving mold 105. In the description of the present embodiment, for convenience, the cross section of the fixed mold 103 or the moving mold 105 is shown by one type of hatching, but these molds may be of a direct carving type or a nested type. It may be a thing. Further, the fixed mold 103 and the moving mold 105 may be combined with a core or the like. A part or all of the mold 101 may be regarded as a part of the die casting machine 1 (and the injection device 9 and the degassing device 27 described later).

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

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

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

The control unit 5 includes, for example, a control device 13 (see FIG. 4) 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 has, for example, a control panel (not shown) having a power supply circuit, a control circuit, and the like, and an operation unit 19 as a user interface.

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

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

When paying attention to the injection device 9 or the degassing device 27 described later in the die casting machine 1, the control unit 5 may be regarded as the control unit of the injection device 9 or the degassing device 27. The same applies to the components of the control unit 5 (for example, the control device 13).

(Configuration of injection device)
FIG. 2 is a cross-sectional view schematically showing the configuration of a main part of the injection device 9.

The injection device 9 includes, for example, a sleeve 21 that communicates with the inside of the mold 101, a plunger 23 that can slide inside the sleeve 21, an injection cylinder 25 that drives the plunger 23, and a degassing that degass the inside of the mold 101. It has a device 27. In the description of the injection device 9, the mold 101 side (left side of the paper in FIG. 1) may be referred to as the front side, and the opposite side may be referred to as the rear side, and the terms forward or backward may be used according to this definition. ..

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

When the 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 position shown in the drawing, the molten metal in the sleeve 21 is pushed out (injected) into the mold 101.

The injection cylinder 25 is composed of, for example, a direct-coupled booster cylinder. That is, the injection cylinder 25 includes a cylinder portion 29, an injection piston 31 and a pressure boosting piston 33 that can slide inside the cylinder portion 29, and a piston rod 35 that extends forward (plunger 23 side) from the injection piston 31. is doing.

The injection piston 31 moves forward by supplying the hydraulic fluid to the rear of the injection piston 31 (front of the pressure boosting piston 33). The injection piston 31 is retracted by supplying the hydraulic fluid in front of the injection piston 31. By supplying the hydraulic fluid to the rear of the pressure boosting piston 33, the hydraulic fluid between the pressure boosting piston 33 and the injection piston 31 is boosted.

The injection cylinder 25 is arranged coaxially (in series) behind the plunger 23. The tip of the piston rod 35 is connected to the rear end of the plunger rod 23b. Therefore, the plunger 23 also moves forward and backward as the injection piston 31 and the piston rod 35 move forward and backward.

The plunger 23 and the piston rod 35 are connected by, for example, a coupling 37. The coupling 37 has, for example, a spacer interposed between the flange provided at the rear end of the plunger rod 23b and the flange provided at the front end of the piston rod 35, although not particularly designated. , Has a case-like portion for accommodating these flanges and spacers.

(Configuration of degassing device)
The degassing device 27 has, for example, an external block 107 attached to the mold 101 and a gas supply unit 39 capable of supplying gas (for example, air) to the external block 107.

The external block 107 is a member that constitutes a part of the exhaust flow path 121 for venting the cavity Ca. The inside of the external block 107 is depressurized according to Bernoulli's theorem by supplying gas from the gas supply unit 39, as will be described in detail later. This facilitates degassing from the cavity Ca.

The external block 107 may be regarded as a part of the mold 101. In the following, the portion of the mold 101 that constitutes the cavity Ca may be referred to as the mold main body 102 in order to distinguish it from the external block 107.

As described above, the mold body 102 may be a direct carving type or a nested type. To be confirmed, the direct carving type mold body 102 is generally composed of a die block in which a shape corresponding to the cavity Ca is directly formed. The nesting mold main body 102 has a nest in which a shape corresponding to the cavity Ca is formed, and a main mold into which the nest is fitted.

(Gas supply unit)
The gas supply unit 39 transfers, for example, the compressor 41, the tank 43 capable of holding the gas compressed by the compressor 41, the atmospheric pressure circuit 45 for controlling the gas flow, and the driving force of the injection cylinder 25 to the compressor 41. It has a connection mechanism 47 for transmitting.

(Compressor and tank)
The compressor 41 is composed of, for example, a reciprocating compressor (reciprocating compressor) among so-called positive displacement compressors. Specifically, the compressor 41 has a cylinder portion 49, a piston 51 slidable inside the cylinder portion 49, and a piston rod 53 extending from the piston 51 to the outside of the cylinder portion 49. The inside of the cylinder portion 49 is divided by a piston 51 into a rod side chamber 49r on the side where the piston rod 53 extends and a head side chamber 49h on the opposite side (divided into two cylinder chambers).

By transmitting the driving force to the piston rod 53 and moving the piston 51 to the rod side chamber 49r, gas can be sent out from the rod side chamber 49r (from another viewpoint, the gas in the rod side chamber 49r can be compressed). Similarly, by transmitting a driving force to the piston rod 53 and moving the piston 51 to the head side chamber 49h, gas can be sent out from the head side chamber 49h (from another viewpoint, the gas in the head side chamber 49h can be compressed).

The tank 43 is a closed container, which communicates with the rod side chamber 49r and the head side chamber 49h, and also communicates with the external block 107. Therefore, for example, the gas compressed by the compressor 41 can be held in the tank 43, and the held gas can be sent to the external block 107 at an appropriate time.

(Atmospheric pressure circuit)
The barometric pressure circuit 45 is, for example, sealing and releasing the compressor 41 (releasing the sealing is, from another point of view, supplying gas (air) to the compressor 41), allowing gas flow from the compressor 41 to the tank 43, and releasing the air pressure circuit 45. It is configured so that it can be prohibited and the flow from the tank 43 to the external block 107 can be allowed or prohibited. The specific configuration may be appropriate.

For example, in the illustrated example, the barometric pressure circuit 45 is provided in the head side valve 55 provided in the flow path communicating the head side chamber 49h and the tank 43, and in the flow path communicating the rod side chamber 49r and the tank 43. It has a rod side valve 57 and a mold side valve 59 provided in a flow path communicating the tank 43 and the external block 107.

The head side valve 55 is composed of, for example, a switching valve having 4 ports and 3 positions (or 3 ports). In the following, the position with the symbol a is referred to as the a position, the position with the symbol b is referred to as the b position, and the position in between is referred to as the neutral position. The head side valve 55 shuts off the head side chamber 49h and the tank 43 in the neutral position, and also seals the head side chamber 49h and the tank 43 (flow paths from these). The head side valve 55 connects the head side chamber 49h and the tank 43 at the a position. At the b position, the head side valve 55 opens the head side chamber 49h to the atmosphere and seals the tank 43. The drive system of the head side valve 55 may be appropriate, but in the illustrated example, a spring for returning to the neutral position, a solenoid for switching to the a position, and a solenoid for switching to the b position are used. The case where it is provided is illustrated.

The rod side valve 57 has, for example, the same configuration as the head side valve 55. The above description of the head side valve 55 may be a description of the rod side valve 57 by replacing the head side valve 55 and the head side chamber 49h with the rod side valve 57 and the rod side chamber 49r.

By setting the head side valve 55 at the b position, the rod side valve 57 at the a position, and moving the piston 51 toward the rod side chamber 49r, the gas in the rod side chamber 49r is sent to the tank 43 and the gas in the tank 43 is accumulated. At the same time, gas can be replenished to the head side chamber 49h whose volume is expanding. Similarly, by setting the rod side valve 57 at the b position, the head side valve 55 at the a position, and moving the piston 51 to the head side chamber 49h side, the gas in the head side chamber 49h is sent out to the tank 43 and the gas in the tank 43. Gas can be replenished to the rod side chamber 49r whose volume is expanded while accumulating the pressure.

The mold side valve 59 is composed of, for example, a 2-port 2-position switching valve having a flow rate control function. At one position, the mold side valve 59 functions, for example, as a check valve, prohibiting the flow from the tank 43 to the external block 107 and allowing the flow in the opposite direction. Further, the mold side valve 59 functions as, for example, a flow rate control valve at another position, allows the flow from the tank 43 to the external block 107, and can adjust the flow rate by adjusting the opening degree. be. The flow rate control valve may or may not have a pressure compensation function.

(Connection mechanism)
The compressor 41 is arranged so that its driving direction is parallel to the driving direction of the plunger 23. Then, the connection mechanism 47 connects the piston rod 53 of the compressor 41 and the plunger 23. As a result, the driving force of the injection cylinder 25 is transmitted to the piston rod 53, and the piston 51 slides in the cylinder portion 49. That is, the compressor 41 is driven by the driving force of the injection cylinder 25.

Further, the connection mechanism 47 can release the connection between the piston rod 53 and the plunger 23. Thereby, for example, when the plunger 23 is driven by the injection cylinder 25, the driving force of the injection cylinder 25 can be left undistributed to the compressor 41 for a predetermined period.

Since the plunger 23 and the piston rod 35 of the injection cylinder 25 are connected, the connection with and from the plunger 23 is the connection with and the release from the piston rod 35 (the movable part of the drive unit that drives the plunger 23). It is synonymous. The same applies to the members other than the piston rod 35, which are fixed to the plunger 23.

The direction of the compressor 41 may be either the rod side chamber 49r or the head side chamber 49h facing forward (mold 101 side). In the illustrated example, the rod side chamber 49r side is the mold 101 side.

The configuration of the connection mechanism 47 may be appropriate. In the illustrated example, the connection mechanism 47 can drive the base 61 fixed to the piston rod 53, the hook 63 swingably supported by the base 61, and the hook 63 supported by the base 61. It has an actuator 65.

The base 61 is a member having an appropriate shape such as a plate shape, and can come into contact with the engaged portion 37a provided on the coupling 37 from the rear. The hook 63 can be brought into contact with the engaged portion 37a from the front (“ON” position in the drawing) and can not be brought into contact with the engaged portion 37a by retracting from the position. It can be moved to and from the position (“OFF” position in the figure).

Therefore, when the plunger 23 is advanced by the injection cylinder 25 with the hook 63 in the ON position, the driving force of the injection cylinder 25 can be transmitted to the compressor 41 as well. Then, if the hook 63 is turned to the OFF position in the middle of the process, the transmission of the driving force can be stopped.

Further, when the plunger 23 is retracted by the injection cylinder 25 in a state where the engaged portion 37a is in contact with the substrate 61 from the front, the driving force of the injection cylinder 25 can be transmitted to the compressor 41 as well. At this time, the hook 63 may be in the OFF position or the ON position.

The actuator 65 is composed of, for example, a gaseous pressure cylinder (for example, an air cylinder), a hydraulic cylinder, or a linear motor. Then, the actuator 65 transmits a linear motion to a portion of the hook 63 that is eccentric from the rotation axis to swing the hook 63, and moves the hook 63 between the ON position and the OFF position.

(Composition of flow path in mold)
FIG. 3A is a cross-sectional view of the external block 107 and its surroundings. FIG. 3B is a plan view of the external block 107. Note that FIG. 3A corresponds to the line IIIa-IIIa of FIG. 3B.

The injection device 9 has an exhaust flow path 121 for discharging the gas in the cavity Ca when injecting the molding material into the cavity Ca, and a decompression flow for reducing the pressure in the exhaust flow path 121 to promote the discharge of the gas. It has roads 119A and 119B (hereinafter, A and B may be omitted).

The exhaust flow path 121 and the decompression flow path 119 as described above are provided in, for example, the mold 101 (the mold main body 102 and the external block 107). The configuration of the flow path in each of the mold main body 102 and the external block 107 is as follows, for example.

(Flow path in the mold body)
The mold main body 102 has, for example, a main body flow path 111 (air vent) that forms a part of the exhaust flow path 121. The main body flow path 111 is formed between, for example, the fixed mold 103 and the moving mold 105, and communicates the cavity Ca with the outside of the mold main body 102. Although not particularly shown, a so-called overflow may be provided between the cavity Ca and the main body flow path 111.

The main body flow path 111 has, for example, a large-diameter portion 111a through which the molding material can penetrate, and a small-diameter portion 111b having a cross-sectional area smaller than that of the large-diameter portion 111a in order to reduce the possibility of the molding material invading. ing. The cross-sectional area of the flow path is the area of the cross section (cross section orthogonal to the flow) unless otherwise specified.

The cross-sectional area or the minimum diameter of the large diameter portion 111a and the small diameter portion 111b may be appropriately set. For example, the cross-sectional area of the large-diameter portion 111a is smaller than the cross-sectional area of the cavity Ca when the cavity Ca is regarded as a flow path from a gate (not shown) to the large-diameter portion 111a. Further, for example, the large diameter portion 111a and the small diameter portion 111b have a thin shape having the minimum diameter in the facing direction of the fixed mold 103 and the moving mold 105 (the facing direction is the thickness direction). The thickness of the large diameter portion 111a is, for example, 0.2 mm or more (for example, about 0.3 mm). The thickness of the small diameter portion 111b is, for example, less than 0.2 mm (for example, about 0.1 mm).

(Structure of external block and its flow path)
The external block 107 has, for example, a fixed side member 113 fixed to the fixed mold 103 and a moving side member 115 fixed to the moving mold 105. However, the external block 107 may be integrally formed as a whole and fixed to one of the fixed mold 103 and the moving mold 105. On the contrary, each of the fixed side member 113 and the moving side member 115 may be composed of a plurality of members. The external block 107 is fixed by, for example, a screw (not shown).

The external block 107 has an external flow path 117 that forms a part of the exhaust flow path 121, and the above-mentioned decompression flow path 119.

The external flow path 117 is configured between, for example, the fixed side member 113 and the moving side member 115. The external flow path 117 may be a through hole provided in the integrally formed member. The external flow path 117 reaches the outside of the mold 101 from the main body flow path 111, and for example, the opening direction of the outlet of the main body flow path 111 (upper in the illustrated example) is the flow path direction as a whole.

The opening direction is, for example, the direction in which the gas is discharged from the opening (however, it is assumed that there is no flow outside the opening other than the discharge), and the surface on which the opening is provided (another). From the viewpoint, it does not always match the orientation of the opening surface). For example, the opening direction of the opening on the left side of the decompression flow path 119A is not diagonally upward but left (horizontal). Further, the flow path direction is the direction in which the fluid flows.

The external flow path 117 has, for example, a connection portion 117a connected to the main body flow path 111, and a divergent portion 117b extending from the connection portion 117a to the outside of the mold 101.

The connecting portion 117a has, for example, a cross-sectional area (and a cross-sectional shape) equivalent to that of the outlet (small diameter portion 111b) of the main body flow path 111, and extends by a predetermined length in the cross-sectional area. The external flow path 117 may not have the connecting portion 117a but may have only the divergent portion 117b.

The divergent portion 117b is formed so that the cross-sectional area becomes larger toward the outer side (outlet side, upper end side in the illustrated example) of the mold 101. The inner surface of the divergent portion 117b may be linear, curved, or both included in a cross-sectional view. Further, the curve may be convex inward, concave inward, or include both of them. The inclination angle of the divergent portion 117b may be appropriately set. The cross-sectional area of the divergent portion 117b may be constant at a part such as the outlet (upper end) side. A shape in which such a portion having a certain cross-sectional area is partially present is also included in a shape (a shape having a wide end) in which the cross-sectional area becomes larger toward the outer side of the mold 101.

The shape of the cross section of the connecting portion 117a and the divergent portion 117b may be appropriate. In the example of FIG. 3B, the shape of the cross section of the connecting portion 117a and the divergent portion 117b is circular. However, these cross-sectional shapes may be other shapes such as a rectangle. When the outlet of the main body flow path 111 has a slit shape, the connecting portion 117a may have a slit shape similar to the shape.

One end of the decompression flow path 119 opens to the exhaust flow path 121 (specifically, the external flow path 117, more specifically, the divergent portion 117b). The opening direction is orthogonal to, for example, the exhaust flow path 121 (the flow path direction of the exhaust flow path 121 at the position where the decompression flow path 119 opens). On the other hand, the other end of the exhaust flow path 121 is connected to the tank 43, and gas is supplied.

Therefore, the gas flows from the decompression flow path 119 into the exhaust flow path 121 in a direction orthogonal to the flow path direction of the exhaust flow path 121. As a result, the exhaust flow path 121 is depressurized according to Bernoulli's theorem. As a result, the gas in the cavity Ca easily flows to the outside of the mold 101.

The orthogonality referred to here does not have to be exactly 90 °. For example, even if the opening direction of the decompression flow path 119 is slightly inclined toward the upstream side of the exhaust flow path 121, if the flow rate from the cavity Ca to the outside of the mold 101 increases due to the decompression effect, , Tolerance or tolerance.

The number of decompression flow paths 119, the position of the outlet (opening on the exhaust flow path 121 side), and the opening direction may be appropriately set. In the illustrated example, two decompression channels 119 are provided. Also, the two decompression channels 119 do not intersect each other, assuming that they extend from the outlet in the opening direction. That is, they are adjacent or separated. More specifically, in the illustrated example, the positions of the outlets and the like of the two decompression flow paths 119 are different from each other (offset) in the vertical direction (flow path direction of the exhaust flow path 121). Therefore, even if it is assumed that it is extended from the exit, it does not intersect with each other. The decompression flow path 119 extends linearly in a direction orthogonal to the exhaust flow path 121, for example. However, the decompression flow path 119 may be appropriately bent or curved.

(The shape of the entire exhaust flow path)
As described above, the exhaust flow path 121 has a large diameter portion 111a, a small diameter portion 111b having a smaller cross-sectional area than the large diameter portion 111a, and a connecting portion 117a having a cross-sectional area equivalent to that of the small diameter portion 111b, in this order from the cavity Ca side. And the divergent portion 117b extending from the cross-sectional area equivalent to that of the connecting portion 117a to the outside of the mold 101 while increasing the area are connected to each other. Therefore, the exhaust flow path 121 as a whole has a shape like a so-called tapered tapered nozzle (Laval nozzle). In the following, the small diameter portion 111b and the connecting portion 117a may be referred to as a throat portion 123 as a portion having the smallest cross section in the exhaust flow path 121.

(Structure of signal processing system)
FIG. 4 is a block diagram showing an outline of the configuration of the signal processing system of the injection device 9.

The control device 13 includes, for example, a CPU, a ROM, a RAM, and an auxiliary storage device, although not particularly shown. Then, various functional units are constructed by the CPU executing the program stored in the ROM and / or the auxiliary storage device.

Specifically, the drive control unit 13a that controls the injection cylinder 25 via the hydraulic pressure circuit 71, the connection control unit 13b that controls the connection mechanism 47 (actuator 65), and the decompression control unit 13c that controls the atmospheric pressure circuit 45 Will be built.

Although not particularly shown, the hydraulic circuit 71 includes, for example, a tank, a pump, an accumulator, a valve, and the like, and supplies the hydraulic fluid to the injection cylinder 25 to drive the injection cylinder 25. The configuration may be similar to various known configurations.

Various signals are input to the control device 13. The signals are input, for example, the position sensor 73 for detecting the position of the input device 17, the plunger 23 (see also FIG. 2), and the tank pressure sensor 75 for detecting the pressure in the tank 43 (see also FIG. 2). , An internal pressure sensor 77 (see also FIG. 3) that detects the pressure on the cavity Ca side of the throat portion 123, and an external pressure sensor 79 that detects the pressure at any position from the throat portion 123 to the outside of the mold 101. (See also FIG. 3).

The position sensor 73 constitutes a linear encoder together with a scale unit (not shown), for example. For example, the position sensor 73 is fixedly provided in front of the cylinder portion 29 of the injection cylinder 25, and the scale portion is provided on the piston rod 35 of the injection cylinder 25 and extends in the axial direction thereof. Then, the position sensor 73 indirectly detects the position of the plunger 23 by detecting the position of the scale portion that moves with the movement of the piston rod 35. The position sensor 73 or the control device 13 can detect the speed by differentiating the detected position.

The internal pressure sensor 77 is provided in, for example, the large diameter portion 111a. When the cross-sectional area gradually decreases from the large diameter portion 111a to the throat portion 123 (small diameter portion 111b), for example, the cross-sectional area is located closer to the cavity Ca than the portion where the cross-sectional area begins to decrease. However, it may be provided in a portion where the cross-sectional area is gradually reduced.

The external pressure sensor 79 is provided at a position where the pressure becomes lower than the external pressure of the mold 101 (however, the pressure is not affected by the exhaust gas, for example, atmospheric pressure) due to the decompression by the depressurizing flow path 119. The external pressure sensor 79 may be provided in either the throat portion 123 or the divergent portion 117b. When the external pressure sensor 79 is provided in the divergent portion 117b, the external pressure sensor 79 may be located on the throat portion 123 side or on the external side of the outlet (opening with respect to the exhaust flow path 121) of the decompression flow path 119. You may be.

(Operation of injection device)
FIG. 5 is a diagram for explaining the operation of the injection device 9. In FIG. 5, the horizontal axis represents time. The graph at the top shows the injection speed, and the vertical axis shows the magnitude of the injection speed. Further, at the lower part of the graph, a timing chart of a head side valve 55, a rod side valve 57, a mold side valve 59, and a hook 63 is shown.

As an overview, the injection device 9 performs a forward step of the plunger 23 (a period of time points t0 to t2) and a backward step of the plunger 23 (a period of time points t3 to t5).

The advance step of the plunger 23 includes, for example, low-speed injection (period from time point t0 to t1) and high-speed injection (period slightly before time point t1 to t2). That is, in the initial stage of injection, the injection device 9 advances the plunger 23 at a relatively low speed in order to prevent air from being entrained in the molten metal, and then fills the molten metal without delaying the solidification of the molten metal. The plunger 23 is advanced at a relatively high speed from the viewpoint of.

Subsequently, although not particularly shown, the injection device 9 increases the pressure of the molten metal in the cavity by the force of the plunger 23 in the forward direction in order to eliminate sink marks on the molded product, and further maintains the increased pressure. Wait for the molded product to solidify. After that, the retreat process of the plunger 23 is performed.

Specific operations in each step are as follows, for example.

(Immediately before the start of injection: Immediately before t0)
Immediately before the start of injection, the injection device 9 is in the state shown in FIG. That is, the plunger 23 (injection piston 31) and the pressure boosting piston 33 are stopped at an initial position such as a retreat limit. The head side valve 55 and the rod side valve 57 are, for example, in the neutral position (closed). The mold side valve 59 is closed, for example. The hook 63 is turned on, for example. The compressed gas is held in the tank 43.

(Low speed injection: t0 to t1)
When the mold clamping of the fixed mold 103 and the moving mold 105 is completed and a predetermined low-speed injection start condition such as the molten metal being supplied to the sleeve 21 is satisfied, the control device 13 advances the plunger 23. Specifically, for example, the control device 13 supplies the hydraulic fluid to the rear of the injection piston 31 by a pump (not shown) of the hydraulic pressure circuit 71, and the speed of the injection piston 31 by the meter-in circuit and / or the meter-out circuit. Feedback control. The speed of the plunger 23 (low speed injection speed _VL ) in low speed injection is, for example, less than 1 m / s.

During this time, for example, the control device 13 sets the head side valve 55 at the b position, the rod side valve 57 at the a position, opens the mold side valve 59, and turns on the hook 63. Therefore, as the plunger 23 advances, the piston 51 of the compressor 41 moves to the rod side chamber 49r. The gas in the rod side chamber 49r is sent to the tank 43, and the head side chamber 49h is replenished with gas from the outside. Further, gas is sent from the tank 43 to the decompression flow path 119.

The plunger 23 advances beyond the supply port 21a, and the molten metal flows toward a gate (not shown), so that the plunger 23 is closer to the front side (sleeve 21 side) than the gate in the sleeve 21 and the mold body 102. The existing gas flows into the cavity Ca. As a result, the pressure in the cavity Ca becomes higher than that outside the mold 101, and the gas inside the cavity Ca is discharged to the outside of the mold 101 via the exhaust flow path 121.

At this time, the outside of the throat portion 123 is depressurized by the gas sent from the depressurizing flow path 119 into the exhaust flow path 121. As a result, the difference between the pressure in the cavity Ca and the pressure outside the throat portion 123 becomes large, and exhaust in the cavity Ca is promoted.

While the gas is being supplied from the gas supply unit 39 to the decompression flow path 119, the control device 13 uses the flow rate by the mold side valve 59 based on the pressure detected by the internal pressure sensor 77 and / or the external pressure sensor 79. Control may be performed. The control at this time may be performed so that the flow velocity in the throat portion 123 becomes the speed of sound, for example, as will be described later.

(High-speed injection: just before t1 to t2)
The control device 13 determines whether or not the position of the plunger 23 has reached a predetermined high-speed switching position in the low-speed injection. The determination may be made as appropriate. For example, the control device 13 determines whether or not the detection position of the position sensor 73 has reached a predetermined high-speed switching position, or determines whether or not a predetermined time has elapsed from the start of injection.

Then, when the control device 13 determines that the high-speed switching position has been reached, the control device 13 controls the hydraulic circuit 71 so that the speed of the injection piston 31 becomes a high-speed injection speed V _{H higher than the low-speed injection speed VL.} Specifically, for example, the control device 13 supplies the hydraulic fluid to the rear of the injection piston 31 from an accumulator (not shown) of the hydraulic circuit 71, and the speed of the injection piston 31 by the meter-in circuit and / or the meter-out circuit. Feedback control.

During this time, the control device 13 sets (closes) the head side valve 55 and the rod side valve 57 to the neutral position (closes) and turns off the hook 63, for example. Therefore, the plunger 23 keeps moving forward, leaving the piston 51 of the compressor 41 behind. Further, backflow of compressed gas from the tank 43 to the compressor 41 is prohibited. The piston 51 basically stays in place. However, it can move until the force due to the pressure of the rod side chamber 49r and the force due to the pressure of the head side chamber 49h are in equilibrium (until the difference is less than the sliding resistance of the piston 51).

Further, in high-speed injection, the control device 13 closes, for example, the mold side valve 59. Therefore, the compressed gas in the tank 43 is retained. However, as shown by the dotted line, the control device 13 may open the mold side valve 59 even in high-speed injection to supply gas from the tank 43 to the decompression flow path 119.

(Pressure increase and pressure retention, etc .: Slightly before t2 to t3)
When the molten metal is filled in the cavity Ca to some extent, the plunger 23 receives a reaction force from the filled molten metal and is decelerated, while the injection pressure rises sharply. Then, when the predetermined pressure increasing start condition is satisfied, the control device 13 starts the pressure increasing step. Specifically, for example, the control device 13 applies hydraulic pressure to the rear of the pressure boosting piston 33 from an accumulator (not shown) of the hydraulic pressure circuit 71. As a result, the pressure of the molten metal reaches a predetermined casting pressure (final pressure). Then, the control device 13 maintains the final pressure and waits until the molten metal is cooled and solidified.

When the molten metal solidifies, although not shown in particular, the control device 13 causes the mold clamping device 7 to open the mold, and the extrusion device 11 extrudes the molded product from the fixed mold 103. At this time, the control device 13 may control the hydraulic circuit 71 so that the injection cylinder 25 generates a driving force for pushing out the biscuit by the plunger 23. That is, extrusion tracking may be performed.

While the pressure increasing and holding pressure are being increased, the head side valve 55, the rod side valve 57, the mold side valve 59 and the hook 63 are maintained in the same state as in the high speed injection, for example.

(Plunger retreat: t3 to t5)
After the holding pressure is completed, or when extrusion tracking is completed, the control device 13 retracts the plunger 23 to the initial position. Specifically, for example, the control device 13 supplies the hydraulic fluid in front of the injection piston 31 from a pump (not shown) of the hydraulic circuit 71 to retract the injection piston 31.

When the plunger 23 is retracted, the plunger 23 reaches the high-speed switching position in which the low-speed injection is switched to the high-speed injection at the time of injection. On the other hand, since the hook 63 was turned off at the high-speed switching position at the time of injection, the substrate 61 remains at the high-speed switching position. Therefore, the engaged portion 37a retracted together with the plunger 23 comes into contact with the substrate 61 from the front. As a result, the piston 51 of the compressor 41 can move to the head side chamber 49h side due to the retracting of the plunger 23.

During this time, for example, the control device 13 sets the head side valve 55 at the a position, the rod side valve 57 at the b position, the mold side valve 59 continues to close, and the hook 63 turns ON. Therefore, as the piston 51 moves to the head side chamber 49h side, the gas in the head side chamber 49h is sent to the tank 43, and the rod side chamber 49r is replenished with gas from the outside. The delivery of gas from the tank 43 to the decompression flow path 119 is prohibited, and the tank 43 is accumulating pressure. The hook 63 may be turned off.

The control device 13 tanks when the pressure detected by the tank pressure sensor 75 does not reach the required pressure before the start of the first molding cycle or between the repeated molding cycles. The injection cylinder 25 may be driven only to accumulate the pressure of 43. Further, the tank 43 may be prevented from exceeding a certain pressure by providing a safety valve or the like.

(Flow in the throat)
The flow in the throat portion 123 and its surroundings will be described with reference to FIGS. 6 (a) to 6 (c).

FIG. 6A is a schematic view showing a model of the flow path, and specifically, the flow path 151 having the tapered portion 153 is shown.

In such a model, the pressure upstream of the tapered portion 153 (on the left side of the paper surface) is P1. Let Pe be the pressure of the throat portion 155 (tapered tip (outlet)) having the minimum cross-sectional area. The pressure downstream of the throat portion 155 (on the right side of the paper) is P2.

FIG. 6B is a diagram showing the relationship between the pressure ratio P2 / P1 (horizontal axis) and the mass flow rate Q (vertical axis) in the flow path 151 of FIG. 6A.

As shown in this figure, if P2 / P1 = 1, gas does not flow in the flow path 151. When P2 / P1 becomes smaller than 1, gas flows from the upstream side to the downstream side in the tapered portion 153 as shown by an arrow in FIG. 6A.

In the range where P2 / P1 is smaller than the critical pressure ratio (about 0.53), the flow velocity is slower than the speed of sound (subsonic speed) and is accelerated by the tapered portion 153. Further, the mass flow rate Q increases as P2 / P1 becomes smaller. The pressure Pe is equivalent to the pressure P2.

When P2 / P1 reaches the critical pressure ratio, the flow velocity at the throat portion 155 (the most accelerated position) reaches the speed of sound. That is, the flow chokes. The pressure Pe is equivalent to the pressure P2.

Then, even if P2 / P1 is made smaller than the critical pressure ratio, the flow velocity in the throat portion 155 remains the speed of sound. The mass flow rate Q also does not increase, and the pressure Pe / P1 remains at the critical pressure ratio.

On the other hand, the exhaust flow path 121 (main body flow path 111) of the die casting machine 1 according to the embodiment has a throat portion 123 whose cross-sectional area is narrowed from the cavity Ca or the large diameter portion 111a, as in the model as described above. Have. Therefore, in the exhaust flow path 121, the mass flow rate can be increased until the flow velocity in the throat portion 123 reaches the speed of sound.

As a result, for example, when the speed of the plunger 23 is relatively low and the flow velocity in the throat portion 123 does not reach the speed of sound, gas is sent from the decompression flow path 119 to the exhaust flow path 121, and the gas is sent from the throat section 123 to the exhaust flow path 121. By reducing the pressure P2 on the downstream side, the amount of exhaust gas from the cavity Ca can be increased.

FIG. 6 (c) is a schematic view showing a model of a flow path different from that of FIG. 6 (a). Specifically, a divergent shape portion 157 is added to the flow path 151 of FIG. 6 (a). The flow path 159 is shown.

In such a model, the pressure on the downstream side of the divergent shape portion 157 is P3. When the pressure ratio P3 / P1 is reduced, the mass flow rate Q increases until the flow in the throat portion 155 reaches the speed of sound, and does not increase thereafter, as in the flow path 151 of FIG. 6A. The flow reaches the speed of sound in the throat section 155 when the pressure Pe in the throat section 155 reaches the critical pressure ratio (about 0.53).

Here, in the flow path 151 of FIG. 6A, Pe = P2 until the flow in the throat portion 155 reaches the speed of sound. On the other hand, in the flow path 159 of FIG. 6B, Pe <P3 until the flow in the throat portion 155 reaches the speed of sound. That is, in the flow path 151, the flow velocity of the throat portion 155 reaches the speed of sound when P2 / P1 drops to the critical pressure ratio, whereas in the flow path 159, P3 / P1 does not reach the critical pressure ratio. The flow velocity of the throat portion 155 reaches the speed of sound.

On the other hand, the exhaust flow path 121 of the die casting machine 1 according to the embodiment has a divergent portion 117b. Therefore, the speed of sound can be easily obtained in the throat portion 155 as compared with the embodiment that does not have the divergent portion 117b (this embodiment is also included in the technique according to the present disclosure).

In the flow path 159, when the flow velocity of the throat portion 155 reaches the speed of sound and then P3 / P1 is further reduced, the flow velocity in the divergent shape portion 157 becomes faster in the subsonic speed range, and further. , Supersonic speed faster than the speed of sound. However, the velocity (sound velocity) and the mass flow rate Q in the throat portion 155 do not change.

(Control during decompression)
In the present embodiment, as described above, when the gas is supplied from the gas supply unit 39 to the decompression flow path 119 in the injection, the control device 13 controls the pressure detected by the internal pressure sensor 77 and / or the external pressure sensor 79. The flow rate may be controlled by the mold side valve 59 based on the above, and this control may be performed so that the flow velocity in the throat portion 123 becomes the speed of sound.

For example, the control device 13 calculates the pressure ratio P _OUT / P _IN when the pressure detected by the internal pressure sensor 77 is set to _PIN and the pressure detected by the external pressure sensor is set to P _OUT. Then, the control device 13 controls the _{mold side valve 59 so that the P OUT} / P _IN becomes equal to or less than the value when the flow velocity in the throat portion 123 reaches the speed of sound. More specifically, for example, the control unit 13, as a target value a value slightly smaller than the value of _P OUT _{/ P IN} when the flow velocity at the throat portion 123 to reach the speed of sound, the detected _P OUT _{/ P IN} The mold side valve 59 is feedback-controlled so that the flow rate increases when is larger than the target value and decreases when the value is smaller than the target value.

_{The value of the pressure ratio P OUT} / P _IN when the flow velocity in the throat portion 123 reaches the speed of sound is theoretically the pressure ratio Pe / P1 of the pressure Pe in the throat portion 123 and the pressure P1 before reaching the tapered shape. Is the corresponding value when becomes about 0.53. The value of such a pressure ratio P _OUT / P _IN is, for example, in an experiment that also serves as a trial run of the die casting machine 1 (including the mold 101) that actually operates, the pressure ratio P is measured while measuring the flow velocity in the throat portion 123. _It may be determined by measuring OUT / _PIN , or such measurement may be performed in an experiment using a model die casting machine, or in a more generalized experiment, or a theoretical calculation. May be sought by.

As described above, in the present embodiment, the injection device 9 has an injection cylinder 25, an exhaust flow path 121, a decompression flow path 119, and a gas supply unit 39. The injection cylinder 25 drives the plunger 23 in the sleeve 21 that communicates with the cavity Ca of the mold 101. The exhaust flow path 121 is a flow path that communicates the cavity Ca with the outside of the mold 101. The exhaust flow path 121 includes a throat portion 123 having a minimum cross-sectional area from the cavity Ca to the outside of the mold 101. One end of the decompression flow path 119 opens in a direction orthogonal to the exhaust flow path 121 on the outside of the throat portion 123. The gas supply unit 39 supplies gas to the other end of the decompression flow path 119, and causes a sound velocity flow in the throat unit 123 when the injection cylinder 25 moves the plunger 23 toward the mold 101 side.

Therefore, for example, as described above, by supplying gas to the outside of the throat portion 123 to reduce the pressure, the mass flow rate in the throat portion 123 can be surely set to the theoretical upper limit value. As a result, for example, the entrainment of gas due to the molten metal is reduced, and the quality of the molded product is improved.

In the present embodiment, the exhaust flow path 121 has a divergent portion 117b that extends from the throat portion 123 to the outside of the mold 101 and has a larger cross-sectional area toward the outer side of the mold 101.

Therefore, for example, as described with reference to FIG. 6 (c), the throat portion does not have to reduce the pressure ratio P3 / P1 to the value of the pressure ratio Pe / P1 (about 0.53) at the time of choking. The speed of sound can be obtained at 123. As a result, for example, the gas supply unit 39 can be miniaturized.

In the present embodiment, the mold 101 has a mold main body 102 and an external block 107 attached to the outside of the mold main body 102. The suehiro portion 117b is located in the external block 107.

Therefore, for example, it is easy to apply the present embodiment to the existing mold body 102. Further, for example, if the external block 107 is diverted when the mold is replaced, the cost can be reduced.

In this embodiment, there are at least two decompression channels 119.

Therefore, for example, the decompression can be performed over a wide range outside the throat portion 123 as compared with the case where there is only one decompression flow path 119. Further, for example, by appropriately setting the positions and directions of two or more decompression flow paths 119, an arbitrary flow can be formed to make the exhaust on the downstream side of the throat portion 123 of the exhaust flow path 121 suitable. It is possible.

Further, in the present embodiment, the two decompression flow paths 119 do not intersect each other when it is assumed that one end on the exhaust flow path 121 side is extended in the opening direction thereof.

Therefore, for example, the possibility that the energies of the gases transmitted from the two decompression channels 119 are canceled out is reduced. As a result, for example, the gas supply unit 39 can be miniaturized.

Further, in the present embodiment, the injection device 9 is provided by the drive control unit 13a that controls the injection cylinder 25 so that low-speed injection and high-speed injection are performed, and the gas supply unit 39 only in low-speed injection among low-speed injection and high-speed injection. It further has a decompression control unit 13c that controls the gas supply unit 39 so as to supply the gas to the decompression flow path 119.

Here, as described with reference to FIG. 6B, when the flow velocity in the throat portion 155 (123) becomes the speed of sound, the mass flow rate Q does not increase even if P2 / P1 is further reduced. On the other hand, in high-speed injection, since the plunger 23 advances at a relatively high speed, it is highly probable that the flow velocity in the throat portion 123 will reach the speed of sound even if the pressure is not reduced outside the throat portion 123. Therefore, by supplying the gas from the gas supply unit 39 only in the low-speed injection among the low-speed injection and the high-speed injection, the possibility of wastefully supplying the gas from the gas supply unit 39 is reduced, for example. From another point of view, the gas supply unit 39 is operated efficiently. As a result, for example, the gas supply unit 39 can be miniaturized and the time for accumulating pressure can be shortened.

In the present embodiment, the injection device 9 has an internal pressure sensor 77 that detects the pressure inside the mold 101 with respect to the throat portion 123, and a pressure at any position from the throat portion 123 to the outside of the mold 101. The ratio of the external pressure sensor 79 to be detected and the pressure P _{OUT detected by the external pressure sensor 79 to the pressure P IN} detected by the internal pressure sensor 77 _{P OUT} / P _IN is less than or equal to the value when sound velocity flow occurs in the throat portion 123. It further has a depressurization control unit 13c that controls the gas supply unit 39 so as to be.

Therefore, for example, the sound velocity flow can be more reliably obtained in the throat portion 123. Further, for example, when the mold body 102 is replaced, or when the operator changes the molding conditions such as the injection speed, the sound velocity flow can be obtained by control.

In the present embodiment, the gas supply unit 39 has a compressor 41 in which the driving force for driving the plunger 23 of the injection cylinder 25 is transmitted to compress the gas.

That is, the injection cylinder 25 is also used as a drive source for the compressor 41. Therefore, for example, a separate drive source for driving the compressor 41 is unnecessary, and miniaturization of the injection device 9 and the like are expected.

In the present embodiment, the compressor 41 is housed in the cylinder portion 49 and the cylinder portion 49, and the inside of the cylinder portion 49 is divided into two cylinder chambers (rod side chamber 49r and head side chamber 49h) and the piston 51. A piston rod 53 that extends from the piston 51 to the outside of the cylinder portion 49 and is connected to the plunger 23. The gas supply unit 39 has a tank 43 and a barometric pressure circuit 45. The tank 43 leads to the decompression flow path 119. The barometric pressure circuit 45 can control the connection and disconnection between the tank 43 and the two cylinder chambers (49r and 49h).

Therefore, for example, gas can be delivered from the compressor 41 to the tank 43 in both the forward and backward movements of the plunger 23. In other words, the degree of freedom in selecting the process that can be used for accumulating pressure in the tank 43 is increased, and the moving distance of the plunger 23 used for accumulating pressure is increased. As a result, for example, the cross-sectional area of the compressor 41 can be reduced to reduce the driving force (instantaneous value) of the injection cylinder 25 with respect to the accumulator.

In the present embodiment, the gas supply unit 39 has a connection mechanism 47 capable of allowing and prohibiting the transmission of the driving force from the injection cylinder 25 to the compressor 41.

Therefore, for example, the driving force of the injection cylinder 25 can be prevented from being distributed to the compressor 41 when there is no need for accumulating pressure. As a result, for example, the injection cylinder 25 can be efficiently operated to reduce the running cost.

In the present embodiment, the injection device 9 has a drive control unit 13a that controls the injection cylinder 25 so that low-speed injection and high-speed injection are performed, and from the injection cylinder 25 to the compressor 41 only in low-speed injection among low-speed injection and high-speed injection. It further includes a connection control unit 13b that controls the connection mechanism 47 so that the driving force is transmitted.

Therefore, for example, when it is necessary to move the plunger 23 at the highest speed, the driving force of the injection cylinder 25 can be prevented from being distributed to the compressor 41. As a result, for example, the injection cylinder 25 or the hydraulic circuit 71 can be miniaturized. Further, for example, when the piston 51 of the compressor 41 is driven at a relatively high speed, the vent may not be able to protect the tank 43 from excessive pressure, but such a possibility is also reduced.

In the above embodiment, the die casting machine 1 is an example of a molding machine, and the injection cylinder 25 is an example of a drive unit.

(Modification example)
Hereinafter, various modifications will be described with reference to FIGS. 7 and 8. In the following, the differences from the embodiments will be mainly described. The points not particularly mentioned may be the same as those in the embodiment. Further, even when the specific configuration is different from the embodiment, the reference numeral used in the embodiment may be used for convenience.

FIG. 7A is a cross-sectional view showing the mold 201 according to the modified example, and corresponds to FIG. 3A. As shown in this figure, the exhaust flow path 121 may include a chill vent 203. Then, the chill vent 203 may form the throat portion 123 having the smallest cross-sectional area. In FIG. 7A, the external block 107 has only the divergent portion 117b as a flow path constituting the exhaust flow path 121. Of course, the external block 107 may have a connecting portion 117a.

FIG. 7B is a cross-sectional view showing the mold 211 according to the modified example, and corresponds to FIG. 3A. As shown in this figure, the mold 211 may be configured without including the external block 107. Then, the divergent portion 117b and the decompression flow path 119 may be provided in the mold main body 102. The divergent portion 117b and the decompression flow path 119 may be directly formed on a die block or the like in which a mold or cavity Ca is directly carved, or a member in which these flow paths are formed is mainly formed. It may be provided by being embedded in a mold, a die block, or the like.

FIG. 8A is a plan view showing the external block 221 according to the modified example, and corresponds to FIG. 3B. As shown in this figure, the two decompression flow paths 119 may have different positions (may be offset) in the direction orthogonal to the flow paths in a plan view. Then, with such a positional relationship, a configuration may be realized in which one end of the two decompression flow paths 119 does not intersect when it is assumed that one end thereof is extended in the opening direction thereof.

FIG. 8B is a cross-sectional view showing the external block 231 according to the modified example, and corresponds to FIG. 3A. As shown in this figure, the opening direction of one end of the decompression flow path 119 is not the direction orthogonal to the exhaust flow path 121, but the downstream direction of the exhaust flow path 121 (downstream of the flow path direction) with respect to the direction orthogonal to the exhaust flow path 121. It may be in the direction of inclining to the side). Further, although not particularly shown, the opening direction of one end of the decompression flow path 119 may be a direction parallel to the downstream direction of the exhaust flow path 121. In any case, the effect of decompression can be obtained by sending the gas from one end of the depressurizing flow path 119 to the outside of the throat portion 123.

Although not particularly shown, the two decompression flow paths 119 in the embodiment have different positions in the vertical direction from each other, and the two decompression flow paths 119 in FIG. 8A are in the plane direction and orthogonal to the flow paths. It may be combined with modes that differ in position in the direction, and each of these modes or combinations may be applied to the orientation of the decompression flow path 119 described with reference to FIG. 8 (b). good.

FIG. 8 (c) is a cross-sectional view showing an exhaust flow path 241 and a decompression flow path 243 according to a modified example, and corresponds to FIG. 3 (a). As shown in this figure, the exhaust flow path 241 does not have to have the divergent portion 117b. Further, the decompression flow path 243 may not be opened in the exhaust flow path 241 but may be opened adjacent to the outside of the exhaust flow path 241. The adjacency referred to here may be any as long as it is possible to affect the speed of the throat portion 123 by decompression by the decompression flow path 243. Further, the decompression flow path 243 may be formed of a tubular member rather than being provided on a block-shaped member such as a mold. Even with the configuration shown in FIG. 8C, the effect of optimizing degassing by depressurization can be obtained.

FIG. 8D is a diagram schematically showing the configuration of a main part of the injection device 251 according to the modified example, and corresponds to FIG. As shown in this figure, the compressor 41 may not be driven by the injection cylinder 25, but by another drive source (eg, motor 253). The electric motor 253 may be a linear motor or a rotary motor. When the electric motor 253 is a rotary type, although not shown in particular, the rotation of the electric motor 253 is converted into a linear motion by an appropriate conversion mechanism such as a screw mechanism, a rack and pinion mechanism, or a link mechanism, and the piston rod. It is transmitted to 53.

The present invention is not limited to the above embodiments and modifications, and may be implemented in various embodiments.

The molding machine (molding machine) is not limited to the die casting machine. For example, the molding machine may be another metal molding machine, an injection molding machine for molding a resin, or a molding machine for molding a material obtained by mixing wood powder with a thermoplastic resin or the like. There may be. Further, the molding machine is not limited to the horizontal clamping horizontal injection, and may be, for example, vertical clamping vertical injection, horizontal clamping vertical injection, or vertical clamping horizontal injection. The gas extracted from the mold and / or the gas supplied to the exhaust flow path is not limited to air, and may be, for example, an inert gas (for example, nitrogen).

The injection device is not limited to the hydraulic type. That is, the drive unit that drives the plunger is not limited to the injection cylinder. For example, the injection device (drive unit) may be a hybrid type including an injection cylinder and an electric motor, or may be an electric type including an electric motor without including a hydraulic device. When the drive unit includes an electric motor, the electric motor may be a linear motor or a rotary type. The rotation of the rotary electric motor is converted into a linear motion by a conversion mechanism such as a screw mechanism, a rack and pinion mechanism, or a link mechanism, and is transmitted to the plunger. The liquid used for the injection cylinder is not limited to oil, and may be, for example, water. The plunger may be screw-shaped.

The injection is not limited to those having low-speed injection and high-speed injection, and may be, for example, one in which the injection speed is constant or continuously increases from the start of injection to the start of pressure increase. Further, the low-speed injection is not limited to the one having a substantially constant speed as a whole, and may be one in which the speed is gradually increased. Multi-speed shifting may be performed.

The time when the flow velocity in the throat portion becomes the speed of sound may be set for an appropriate time of injection in various modes. The length of the period during which the flow velocity in the throat portion becomes the speed of sound may also be appropriately set, and may be, for example, a small part of the low-speed injection.

The compressor is not limited to a type that changes the volume, and may be, for example, a turbo compressor. Further, the compressor that changes the volume is not limited to the reciprocating type, and may be, for example, a type in which rotation is transmitted and driven.

Even in a mode in which the compressor is driven by the driving force of the driving unit that drives the plunger, the type of driving unit (for example, hydraulic type, hybrid type or electric type) and the type of compressor (for example, reciprocating positive displacement compressor). The combination with a rotary volumetric compressor or a turbo compressor) may be various.

Further, the transmission of the driving force from the driving unit to the compressor may be a transmission path different from the transmission path of the driving force from the driving unit to the plunger. The rotational motion may be transmitted from the drive unit to the compressor instead of transmitting the linear motion that drives the plunger.

Specifically, for example, in a mode in which the drive unit includes a rotary motor and the rotation of the motor is converted into linear motion and transmitted to the plunger, the rotation of the motor is provided separately from the transmission path to the plunger. Further, it may be transmitted to the rotary compressor via a transmission mechanism that transmits rotation such as a gear mechanism or a pulley / belt mechanism.

Further, for example, the rotation of the electric motor may be transmitted to the reciprocating compressor via a conversion mechanism for converting the rotation of the electric motor into a linear motion, which is provided separately from the transmission path to the plunger. Even if the linear motion is transmitted to the compressor in the same manner as the plunger, it is possible to make the speed different between the plunger and the compressor, for example, by separating the paths.

The configuration of the connection mechanism that allows and prohibits the transmission of the driving force from the drive unit that drives the plunger to the compressor is not limited to the transmission of linear motion, is not limited to the transmission of linear motion, and advances the plunger. It is not limited to those that can be prohibited from communicating only with respect to. For example, the connecting mechanism may be a meshing clutch, a friction clutch, or a fluid clutch in a mode in which rotation is transmitted from the drive unit to the compressor. Further, for example, in a mode in which the linear motion is transmitted from the drive unit to the compressor, the connecting mechanism has a plurality of teeth arranged in the direction of the linear motion and a position where the teeth are engaged with and a position where the teeth are separated from each other. It may be possible to allow or prohibit the transmission of driving force in both directions and at any position, such as having a claw that moves between.

From the present disclosure, the following techniques that do not require decompression by sending gas from the decompression flow path can be extracted.
A drive unit that can drive the plunger in the sleeve leading to the mold cavity,
An exhaust flow path that communicates the cavity with the outside of the mold and includes a throat portion having a minimum cross-sectional area from the cavity to the outside of the mold.
Have and
The exhaust flow path is an injection device having a divergent portion that extends from the throat portion to the outside of the mold and has a larger cross-sectional area toward the outer side of the mold.

1 ... Die casting machine (molding machine), 9 ... Injection device, 21 ... Sleeve, 23 ... Plunger, 25 ... Injection cylinder (drive unit), 39 ... Gas supply unit, 101 ... Mold, 119 ... Decompression flow path, 121 ... Exhaust flow path, 123 ... Throat, Ca ... Cavity.

Claims (12)

The drive unit that drives the plunger in the sleeve leading to the mold cavity,
An exhaust flow path that communicates the cavity with the outside of the mold,
With
The exhaust flow path has a throat portion that minimizes the cross-sectional area of a part of the flow path.
Further, a decompression flow path that opens in a direction orthogonal to the exhaust flow path or toward the downstream side of the exhaust flow path in a portion outside the throat portion.
A gas supply unit that supplies gas to one end of the decompression flow path and causes a sound velocity flow in the throat unit when the drive unit moves the plunger to the mold side.
Have and
The exhaust flow path has a divergent portion having a larger cross-sectional area from the throat portion toward the outer side of the mold.
The decompression flow path is an injection device that is open at the wide end. The drive unit that drives the plunger in the sleeve leading to the mold cavity,
An exhaust flow path that communicates the cavity with the outside of the mold,
With
The exhaust flow path has a throat portion that minimizes the cross-sectional area of a part of the flow path.
Further, a decompression flow path that opens in a direction orthogonal to the exhaust flow path or toward the downstream side of the exhaust flow path in a portion outside the throat portion.
A gas supply unit that supplies gas to one end of the decompression flow path and causes a sound velocity flow in the throat unit when the drive unit moves the plunger to the mold side.
Have and
It has at least two decompression channels.
The two decompression flow paths are offset in at least one of the flow path direction of the exhaust flow path and the direction orthogonal to the flow path direction.
Y de devices. The drive unit that drives the plunger in the sleeve leading to the mold cavity,
An exhaust flow path that communicates the cavity with the outside of the mold,
With
The exhaust flow path has a throat portion that minimizes the cross-sectional area of a part of the flow path.
Further, a decompression flow path that opens in a direction orthogonal to the exhaust flow path or toward the downstream side of the exhaust flow path in a portion outside the throat portion.
A gas supply unit that supplies gas to one end of the decompression flow path and causes a sound velocity flow in the throat unit when the drive unit moves the plunger to the mold side.
Have and
A drive control unit that controls low-speed injection and high-speed injection of the drive unit,
A decompression control unit that controls the gas supply unit so as to supply gas from the gas supply unit to the decompression flow path only during the low speed injection among the low speed injection and the high speed injection.
Further comprising optionally that y de device. The drive unit that drives the plunger in the sleeve leading to the mold cavity,
An exhaust flow path that communicates the cavity with the outside of the mold,
With
The exhaust flow path has a throat portion that minimizes the cross-sectional area of a part of the flow path.
Further, a decompression flow path that opens in a direction orthogonal to the exhaust flow path or toward the downstream side of the exhaust flow path in a portion outside the throat portion.
A gas supply unit that supplies gas to one end of the decompression flow path and causes a sound velocity flow in the throat unit when the drive unit moves the plunger to the mold side.
Have and
An internal pressure sensor that detects the pressure inside the mold rather than the throat, and
An external pressure sensor that detects the pressure at any position from the throat to the outside of the mold,
The gas supply unit is provided so that the ratio P _OUT / P _{IN of the pressure P OUT} detected by the external pressure sensor _{to the pressure P IN} detected by the internal pressure sensor is equal to or less than the value when a sound velocity flow occurs in the throat unit. The decompression control unit to control and
Further comprising optionally that y de device. The drive unit that drives the plunger in the sleeve leading to the mold cavity,
An exhaust flow path that communicates the cavity with the outside of the mold,
With
The exhaust flow path has a throat portion that minimizes the cross-sectional area of a part of the flow path.
Further, a decompression flow path that opens in a direction orthogonal to the exhaust flow path or toward the downstream side of the exhaust flow path in a portion outside the throat portion.
A gas supply unit that supplies gas to one end of the decompression flow path and causes a sound velocity flow in the throat unit when the drive unit moves the plunger to the mold side.
Have and
The gas supply unit has a compressor in which a driving force for driving the plunger of the driving unit is transmitted to compress the gas.
Y de devices. The compressor
Cylinder part and
A piston housed in the cylinder portion and partitioning the inside of the cylinder portion into two cylinder chambers,
It has a piston rod that extends from the piston to the outside of the cylinder portion and is connected to the plunger.
The gas supply unit
The tank leading to the decompression flow path and
The injection device according to claim 5 , further comprising a barometric pressure circuit capable of controlling connection and disconnection between the tank and the two cylinder chambers. The injection device according to claim 5 or 6 , wherein the gas supply unit has a connection mechanism capable of allowing and prohibiting transmission of a driving force from the driving unit to the compressor. A drive control unit that controls low-speed injection and high-speed injection of the drive unit,
A connection control unit that controls the connection mechanism so that a driving force is transmitted from the drive unit to the compressor only during low-speed injection among the low-speed injection and the high-speed injection.
The injection device according to claim 7 , further comprising. The injection device according to any one of claims 2 to 8, wherein the exhaust flow path has a divergent portion having a large cross-sectional area from the throat portion toward the outside of the mold. The injection device according to any one of claims 1 and 3 to 9, which has at least two decompression channels. The injection device according to any one of claims 1 to 10, and the injection device.
A mold clamping device that clamps the mold and
Molding machine that has. An exhaust flow path including a throat portion leading to the cavity of the mold and a divergent portion having a large cross-sectional area from the throat portion toward the outside of the mold.
A pressure reducing channel which opens Te in the divergent portion toward the downstream side of the direction perpendicular to the exhaust passage, or the exhaust passage,
Gas supply to one end of the pressure reducing channel, the throat portion gas supply to cause sonic flow into the plunger in the sleeve which opens into the mold cavity when it is moved to the mold side Department and
Have and
The throat portion is a portion of the exhaust flow path where the cross-sectional area is minimized.
Degassing device.

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