Wave pressure absorbing device, hydraulic device for wave pressure absorbing device, forming machine, and hydraulic cylinder

Abstract

The fluctuating pressure absorption device (2) has a check valve (51) connected to a hydraulic cylinder (43). In the cylinder (43), a rod (49) is fixed to an advancing / retreating member (41) that can advance into the mold (101) and retreat to the opposite side thereof. The piston (47) is fixed to the rod (49). The cylinder member (45) houses the piston (47). The interior of the cylinder member (45) is divided by the piston (47) into a rod-side chamber (45r) in which the rod (49) is located and a head-side chamber (45h) on the opposite side of the rod-side chamber (45r). The one-way valve (51) permits flow from the head-side chamber (45h) to the rod-side chamber (45r) and prohibits flow in the opposite direction during movement of the piston (47) from the side of the rod-side chamber (45r) to the side of the head-side chamber (45h) by retracting the advancing / retracting member (41) due to the pressure of the molten metal (109) in the mold (101).

Description

Technical Field

[0001] This disclosure relates to a pressure fluctuation absorbing device, a hydraulic device for the pressure fluctuation absorbing device, a molding machine including the pressure fluctuation absorbing device, and a hydraulic cylinder that can be used in the pressure fluctuation absorbing device. The molding machine is, for example, a die-casting machine for forming metal or an injection molding machine for forming resin. Background Technology

[0002] In molding machines that manufacture molded parts by injecting molding material (e.g., molten metal) into a mold cavity using a plunger to press the material into the cavity, a process known as wave pressure is generated. Wave pressure is a relatively large, instantaneous pressure that occurs when the molding material has largely filled the mold cavity and lost its flow path (when filling is largely complete). If the wave pressure is too large, it can cause, for example, burrs. Burrs are portions (undesirable portions) formed when the molding material is squeezed out towards the periphery of the cavity.

[0003] Patent Document 1 discloses a technique for localized pressurization of molding material filled in a cavity using an extrusion pin. In Patent Document 1, the extrusion pin is driven by a hydraulic cylinder. Patent Document 1 proposes to perform localized pressurization by advancing the extrusion pin with a first pressure, followed by performing localized pressurization by advancing the extrusion pin with a second pressure higher than the first pressure (performing two stages of localized pressurization).

[0004] Patent Document 2 proposes a technique for reducing fluctuating pressure using a localized pressurization device. Specifically, in Patent Document 2, before injecting molding material into the cavity, the pressurizing member (extrusion pin) is kept at its forward limit. At this time, a first pressure is applied to the hydraulic cylinder driving the pressurizing member via an accumulator. Subsequently, if molding material is injected and reaches the pressurizing member, the pressurizing member retracts due to the pressure of the molding material. This absorbs the fluctuating pressure. Then, a second pressure higher than the first pressure is applied to the cylinder. This causes the pressurizing member to advance, performing localized pressurization.

[0005] Patent documents 3 and 4 disclose a flow path connecting two cylinder chambers (rod-side chamber and head-side chamber) in a hydraulic cylinder that drives a pressure plunger (extrusion pin), and a valve provided in the flow path. This flow path is used for venting (exhausting) air from the cylinder.

[0006] Patent documents 5-7 disclose techniques for loading a mold (a mold different from the mold constituting the mold cavity) into a mold cavity and a hydraulic cylinder for driving it. In these documents, for cooling and venting purposes, a flow path connecting the front cylinder chamber (rod side chamber) and the rear cylinder chamber (head side chamber) and a valve related to the opening and closing of the flow path are disclosed.

[0007] More specifically, for example, in patent document 5 Figure 3The present invention discloses a one-way valve that allows flow from the head chamber to the rod chamber and prohibits flow in the opposite direction. A throttle orifice and a relief valve are installed between the head chamber and the one-way valve. When working oil is supplied to the head chamber and the piston reaches its forward limit (the drive limit on one side of the rod chamber), the pressure in the head chamber rises, and the relief valve opens. The working oil in the head chamber flows sequentially through the one-way valve and the rod chamber to the reservoir. This replacement of the working oil cools the cylinder and also vents air.

[0008] Furthermore, Patent Document 6 discloses a control valve built into a piston. The control valve includes a one-way valve that allows flow from the head-side chamber to the rod-side chamber and prohibits flow in the opposite direction. However, the control valve includes other one-way valves connected in series and in the opposite direction to the aforementioned one-way valve, configured to prohibit flow in either direction as long as the piston has not reached its retraction limit (the drive limit on one side of the head-side chamber).

[0009] Furthermore, Patent Document 6 discloses a control valve built into a piston. The control valve is configured to open without being opened by the pressure in the rod-side chamber or the head-side chamber, but rather when the forward or backward limit is reached.

[0010] Patent document 8 discloses a cylinder capable of connecting the rod-side chamber and the head-side chamber.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: Japanese Patent Application Publication No. 2016-196009

[0014] Patent Document 2: Japanese Patent No. 7137729

[0015] Patent Document 3: Japanese Patent Application Publication Nos. 2021-20224

[0016] Patent Document 4: International Publication No. 2021 / 14707

[0017] Patent Document 5: Japanese Patent Application Publication No. 2022-31101

[0018] Patent Document 6: Japanese Patent Application Publication No. 2006-207792

[0019] Patent Document 7: Japanese Patent Application Publication No. 2013-7407

[0020] Patent Document 8: (Japan) Published Patent No. 58-76805 Summary of the Invention

[0021] The technical problem that the invention aims to solve

[0022] The present invention provides a wave pressure absorbing device that can improve the responsiveness of wave pressure absorption, a hydraulic device for the wave pressure absorbing device and a forming machine, and a hydraulic cylinder that can be used in the wave pressure absorbing device.

[0023] Technical solutions for solving technical problems

[0024] This disclosure discloses a pressure fluctuation absorption device comprising a hydraulic cylinder and a one-way valve. The cylinder has a rod, a piston, and a cylinder assembly. The rod is fixed to a retractable member capable of advancing into the mold and retracting to the opposite side. The piston is fixed to the rod. The cylinder assembly houses the piston. The interior of the cylinder assembly is divided by the piston into a rod-side chamber containing the rod and a head-side chamber on the opposite side. The one-way valve allows flow from the head-side chamber to the rod-side chamber and prohibits flow in the opposite direction as the piston moves from one side of the rod-side chamber to the other side of the head-side chamber due to the retraction of the retractable member caused by the pressure of the molding material within the mold.

[0025] This disclosure discloses a hydraulic device for absorbing fluctuation pressure, connected to a hydraulic cylinder. The cylinder has a rod, a piston, and a cylinder assembly. The rod is fixed to a retractable member capable of advancing into a mold and retracting to the opposite side. The piston is fixed to the rod. The cylinder assembly houses the piston. The interior of the cylinder assembly is divided by the piston into a rod-side chamber containing the rod and a head-side chamber on the opposite side. The hydraulic device has a bypass circuit. The bypass circuit connects the rod-side chamber and the head-side chamber during the retractable member's movement due to the pressure of the forming material within the mold, causing the piston to move from one side of the rod-side chamber to the other side of the head-side chamber.

[0026] A molding machine according to one aspect of the present disclosure includes: the fluctuation pressure absorbing device; a mold clamping device that holds the mold; and an injection device that injects molding material into the mold.

[0027] This disclosure discloses a hydraulic cylinder comprising a cylinder assembly, a piston, a rod, and a one-way valve. The piston is housed in the cylinder assembly, dividing the interior of the cylinder assembly into a rod-side chamber and a head-side chamber. The rod is fixed to the piston and extends outward from the cylinder assembly via the rod-side chamber. The one-way valve is included in the piston, allowing flow from the head-side chamber to the rod-side chamber and preventing flow in the opposite direction as the piston moves from one side of the rod-side chamber to the side of the head-side chamber.

[0028] Invention Effects

[0029] Based on the above structure, for example, the responsiveness of absorbing fluctuating pressure can be improved. Attached Figure Description

[0030] Figure 1 middle, Figure 1 (a) is a schematic diagram illustrating the outline of the wave pressure absorption device for the implementation method. Figure 1 (b) is Figure 1 (a) Enlarged view of region Ib.

[0031] Figure 2 middle, Figure 2 (a) means Figure 1 (a) is a diagram illustrating the subsequent action. Figure 2 (b) is Figure 2 (a) Enlarged view of region IIb.

[0032] Figure 3 It means Figure 1 A schematic diagram of the main structure of the fluctuation pressure absorption device.

[0033] Figure 4 This is a side view showing the structure of the main parts of the die-casting machine according to the embodiment.

[0034] Figure 5 This is a schematic diagram illustrating the state of fluctuation pressure absorption in a fluctuation pressure absorption device.

[0035] Figure 6 It means Figure 5 The following diagram.

[0036] Figure 7 It means Figure 6 The following diagram.

[0037] Figure 8 It means Figure 7 The following diagram.

[0038] Figure 9 This is a diagram used to illustrate the injection process. Detailed Implementation

[0039] (Summary of the fluctuation pressure absorption device according to the embodiment)

[0040] Figure 1 (a) ~ Figure 2 (b) is a schematic diagram showing the general operation of the fluctuation pressure absorption device 2 (hereinafter, sometimes simply referred to as "absorption device 2") and the injection device 9 in the embodiment.

[0041] Figure 1 (a) and Figure 2 (a) schematically represents the absorption device 2 and the injection device 9, and further represents the states at different times during the molding cycle (more specifically, the injection cycle). Figure 1 (b) is Figure 1(a) Enlarged view of region Ib. Figure 2 (b) is Figure 2 (a) Enlarged view of region IIb.

[0042] Figure 1 (a) indicates the state of an injection process in which a forming material (e.g., molten metal, i.e., molten metal 109) is injected into the interior of the mold 101. In the injection process, as indicated by arrow a1, the plunger 21 (injection plunger) moves toward the mold 101, thereby pushing the molten metal 109 in the sleeve 19 into the interior of the mold 101 (cavity 107).

[0043] Figure 2 (a) indicates Figure 1 (a) The state afterward. When the injection process is performed, the molten metal 109 covers approximately the entire cavity 107. Figure 2 (a) indicates such a state. It should be noted that, in the description of the implementation method, the state in which this state is reached is sometimes referred to as filling completion. When filling is complete, the plunger 21 presses against the molten metal 109, which has lost its flow path, causing the pressure of the molten metal 109 to rise. At this time, sometimes a so-called fluctuating pressure, which is accompanied by a temporary and rapid pressure rise, is also generated.

[0044] In this embodiment, a retraction member 41 capable of advancing into the cavity 107 and retracting to the opposite side is provided, and a cylinder 43 fixed to the retraction member 41 is provided. The cylinder 43 is a hydraulic (e.g., oil-pressure) cylinder.

[0045] like Figure 1 (a) and Figure 1 As shown in (b), before filling is complete (or, from another perspective, before the molten metal reaches the advancing / retracting component 41), the advancing / retracting component 41 is in an initial position (e.g., the advancing limit) further forward (towards the cavity 107 side) than the retracting limit. Then, when the molten metal 109 reaches the position of the advancing / retracting component 41, and furthermore, the force by which the molten metal 109 presses the advancing / retracting component 41 backward exceeds a certain magnitude, as shown by arrow a2 ( Figure 2 (a) and arrow a3 ( Figure 2 As shown in (b), the forward / reverse component 41 moves backward. It should be noted that the forward / reverse component 41 may or may not reach the backward limit.

[0046] The force of the retracting component 41 is transmitted to the cylinder 43, driving the cylinder 43. Alternatively, the retracting component 41 retracts while being resisted by a force from the cylinder 43. This, for example, applies a certain degree of pressure to the molten metal 109 and absorbs at least a portion of the fluctuating pressure.

[0047] After the absorption device 2 is moved forward by the advance / retraction member 41, so-called local pressurization can be performed. However, the absorption device 2 can also be used only for absorbing fluctuating pressure without performing such local pressurization. In the description of the embodiment, the method of performing local pressurization is mainly used as an example.

[0048] Figure 3 This is a schematic diagram showing the structure of the main parts of the absorption device 2. It should be noted that, regarding cylinder 43, Figure 3 left and right directions and Figure 1 (a) The left and right directions are the same. Therefore, the forward and backward movement component 41 is located relative to the cylinder 43. Figure 3 On the left side.

[0049] Cylinder 43 comprises the following components: a rod 49 fixed to the advance / retractor 41; a piston 47 fixed to the rod 49; and a cylinder component 45 housing the piston 47. The interior of the cylinder component 45 is divided by the piston 47 into a rod-side chamber 45r containing the rod 49 and a head-side chamber 45h on the opposite side. The rod 49 extends outward from the cylinder component 45 via the rod-side chamber 45r, and its front end is fixed to the advance / retractor 41.

[0050] It should be noted that the term "fixed" can be interpreted broadly as long as it does not create contradictions. For example, fixing two parts can be achieved by forming them integrally from the same material, or by manufacturing them independently and connecting them using screws or the like. Alternatively, other parts can be sandwiched between them. Furthermore, below, the movement of the piston 47 towards the rod-side chamber 45r is sometimes referred to as "forward," and the movement towards the opposite side is sometimes referred to as "reverse."

[0051] When the retracting component 41 retracts due to the pressure of the molten metal filling the cavity 107, the piston 47 also retracts. That is, the volume of the head-side chamber 45h decreases. At this time, the working fluid can be discharged from the head-side chamber 45h. Alternatively, in another viewpoint, when the piston 47 retracts, the volume of the rod-side chamber 45r increases. At this time, the working fluid can be replenished to the rod-side chamber 45r.

[0052] The destination of the working fluid discharged from the head chamber 45h is arbitrary. In the illustrated example, an accumulator 65 is connected to the head chamber 45h. Therefore, for example, if the pressure in the head chamber 45h exceeds the pressure in the accumulator 65, the working fluid in the head chamber 45h flows into the accumulator 65. In another viewpoint, the pressure in the head chamber 45h is maintained approximately at the same level as the pressure in the accumulator 65. Thus, for example, the absorption device 2 can absorb fluctuating pressure and apply a certain level of pressure to the molten metal.

[0053] It should be noted that, for example, if the volume of the flow path between the head chamber 45h and the accumulator 65 is relatively large, and the amount of working fluid discharged from the head chamber 45h is relatively small, the working fluid in the head chamber 45h may not necessarily reach the accumulator 65. However, for convenience in this disclosure, even in the aforementioned cases, the working fluid in the head chamber 45h may sometimes flow into the accumulator 65. The same applies to the flow of fluids in other parts of the molding machine.

[0054] The absorption device 2 may have a one-way valve 51, which allows flow from the head chamber 45h to the rod chamber 45r and prevents flow in the opposite direction during the retraction of the advancing / retracting member 41 and the piston 47 due to the pressure of the molten metal (in other words, in a midway position). In this case, if the pressure difference between the head chamber 45h and the rod chamber 45r increases to a certain extent (or approximately zero), the working fluid in the head chamber 45h flows into the rod chamber 45r. The one-way valve 51 (or, in other views, a flow path 61 including the one-way valve 51) can be located in any position. In the illustrated example, the one-way valve 51 (flow path 61) is located on the piston 47.

[0055] Additionally, the absorption device 2 may have a bypass circuit 53 that connects the head chamber 45h and the rod chamber 45r during the retraction of the advancing / retracting component 41 and the piston 47 due to the pressure of the molten metal. In this case, if the pressure in the head chamber 45h increases relative to the pressure in the rod chamber 45r, the working fluid in the head chamber 45h flows into the rod chamber 45r. The specific structure of the bypass circuit 53 is arbitrary. In the illustrated example, the switching valve 55 is in the neutral position, thereby connecting the head chamber 45h, the rod chamber 45r, and the pump 57 (an example of a hydraulic source) to form the bypass circuit 53.

[0056] The cross-sectional area (orthogonal to the axis) of the head chamber 45h is larger than the cross-sectional area of ​​the rod 49, which is greater than the cross-sectional area of ​​the rod chamber 45r. Therefore, when the piston 47 retracts, the amount of working fluid discharged from the head chamber 45h is greater than the amount of working fluid supplied to the rod chamber 45r. This difference flows from the head chamber 45h to the accumulator 65, for example, as described above.

[0057] By providing a one-way valve 51 and / or a bypass circuit 53, the absorption device 2 can respond responsively to instantaneous pressure changes, i.e., fluctuating pressure. Specifically, as described below.

[0058] Although not specifically illustrated, as a comparative example, it can be cited that there is no one-way valve 51 and bypass circuit 53, and the rod-side chamber 45r and the liquid reservoir 59 ( Figure 5The connection method is as follows: In this method, when the piston 47 retracts, the expanded rod-side chamber 45r draws the working fluid from the reservoir 59 through negative pressure. In this case, the resistance generated in the rod-side chamber 45r increases with the retraction of the piston 47.

[0059] On the other hand, when a one-way valve 51 and / or a bypass circuit 53 are provided, the working fluid is supplied to the rod-side chamber 45r by utilizing the pressure of the head-side chamber 45h that rises with the retraction of the piston 47. As a result, the retraction of the piston 47 is easier compared to the comparative example described above. Consequently, it is easier to release instantaneous pressure fluctuations, i.e., volatile pressure, to the absorption device 2.

[0060] It should be noted that the flow path 61, including the check valve 51, can be understood as a type of bypass circuit. The bypass circuit 53 can be considered a circuit that independently connects the rod-side chamber 45r and the head-side chamber 45h, separate from the flow path 61. In the illustrated example, both the check valve 51 (flow path 61) and the bypass circuit 53 are provided. However, only one may be provided. For example, the bypass circuit 53 may not be provided at all.

[0061] The above is a summary of the implementation methods. The implementation methods will now be described in a general order.

[0062] 1. Die casting machine ( Figure 4 )

[0063] 1.1. Die-casting machine as a whole

[0064] 1.2. Main body of the machine

[0065] 1.3. Control Device

[0066] 1.4. Other structures of the die-casting machine

[0067] 2. Forward and backward movement components ( Figure 1 (b)

[0068] 3. The cylinder and check valve of the absorption device ( Figure 3 )

[0069] 3.1. Operation of cylinder and check valve

[0070] 3.2. Cylinder Structure

[0071] 3.3. Structure of a one-way valve

[0072] 4. Hydraulic device of the absorption unit ( Figures 5-8 )

[0073] 4.1. Structure from cylinder to accumulator

[0074] 4.2. Structure from pump and reservoir to cylinder

[0075] 4.3. Other structures of the hydraulic device

[0076] 5. The operation of the injection device ( Figure 9 )

[0077] 6. Operation of the absorption device

[0078] 6.1. State before absorbing fluctuation pressure ( Figure 5 )

[0079] 6.2. The action of absorbing fluctuating pressure ( Figure 5 )

[0080] 6.3. Localized pressurization actions ( Figure 6 )

[0081] 6.4. Spraying action ( Figure 7 )

[0082] 6.5. Preparatory actions for absorbing fluctuating pressure ( Figure 8 )

[0083] 7. Summary of Implementation Methods

[0084] (1. Die-casting machine)

[0085] (1.1. Die-casting machine as a whole)

[0086] Figure 4 This is a side view (partially including a cross-sectional view) showing the structure of the main parts of a die-casting machine DC (an example of a forming machine) with a mold according to an embodiment. (Refer to...) Figure 4 In the explanations provided, for convenience, sometimes... Figure 4 The left side is called the front. Figure 4 The right side is called the rear.

[0087] The die-casting machine DC with mold has a mold (mold 101), a forward / backward component 41, and a die-casting machine 1 (which is also an example of a forming machine) holding the mold 101. The die-casting machine 1 has a machine body 3 that performs mechanical actions and a control device 5 that controls the machine body 3. The die-casting machine DC with mold or the die-casting machine 1 (or the machine body 3) has the aforementioned absorption device 2 ( Figure 1 (a) The structure and operation of the constituent elements other than the absorption device 2 can be known structures and operations, or they can be new structures and operations; in other words, they can be in various ways. It should be noted that for structures and operations that can be known structures and operations, the description is appropriately omitted.

[0088] As already mentioned, the die-casting machine 1 manufactures products (molten parts, die-cast parts) made of solidified molding material by injecting (filling) molten molding material into the cavity 107. The molding material can be, for example, a metal such as aluminum. It should be noted that, instead of molten molding material, molding material in a solid-liquid coexisting state (semi-solid or semi-molten state) can also be injected into the cavity 107.

[0089] Mold 101, for example, has a fixed mold 103 and a movable mold 105 opposite to the fixed mold 103. The main part of the cavity 107 is formed between the fixed mold 103 and the movable mold 105. The fixed mold 103 is a non-moving mold. The movable mold 105 is a mold that moves in a direction opposite to the fixed mold 103 (mold opening and closing direction). The mold opening and closing direction is, for example, the horizontal direction. Figure 4 In the figures, for convenience, the cross-sections of the fixed mold 103 or the movable mold 105 are indicated by a shaded line. However, these molds can be either straight-cut or nested. Additionally, the fixed mold 103 and / or the movable mold 105 may include a mold base.

[0090] (1.2. Main body of the machine)

[0091] The machine body 3 includes, for example, a mold closing device 7 for opening and closing the mold 101, an injection device 9 for injecting molten metal into the cavity 107, and an ejection device (not shown) for ejecting the product formed by solidifying the molten metal from the fixed mold 103 or the moving mold 105.

[0092] The mold closing device 7 includes, for example, a base 11, a fixed template 13 fixed to the base 11, a movable template 15 movable on the base 11 in the mold opening and closing direction, and multiple (e.g., four) connecting rods 17 inserted through these templates. The fixed template 13 and the movable template 15 are opposite to each other in the mold opening and closing direction. The fixed template 13 holds the fixed mold 103 on the surface opposite to the movable template 15. The movable template 15 holds the movable mold 105 on the surface opposite to the fixed template 13. The mold 101 is opened and closed by moving the movable template 15 in the mold opening and closing direction. In addition, by extending the connecting rods 17 in the mold closing state, a mold closing force corresponding to the extension amount is applied to the mold 101.

[0093] The injection device 9 is located behind the fixed template 13 (on the side opposite to the movable template 15). As already mentioned, the injection device 9 has a sleeve 19 communicating with the cavity 107, a plunger 21 that pushes the molten metal in the sleeve 19 into the cavity 107, and a drive unit 23 that drives the plunger 21. It should be noted that the sleeve 19 and the plunger 21 can be understood as consumables, so the drive unit 23 can also be understood as the injection device itself.

[0094] The drive unit 23 can be driven by, for example, a hydraulic (e.g., oil pressure), electric, or hybrid (a combination of hydraulic and electric). Figure 1 (a) illustrates a hydraulic drive unit 23. That is, the drive unit 23 has a hydraulic cylinder (injection cylinder) connected to the plunger 21 and a hydraulic device (not shown) for supplying working fluid (e.g., working oil) to the injection cylinder.

[0095] (1.3. Control device)

[0096] Although not specifically illustrated, the control device 5 may be configured to include a computer. The computer, though not specifically illustrated, may be configured to include a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and external storage devices (such as HDD (Hard Disk Drive) or SSD (Solid State Drive)). The CPU executes programs stored in the ROM and / or external storage devices, thereby constructing various functional units that perform various operations (including control). Furthermore, the control device 5 may include logic circuits that perform certain actions, power supply circuits, and drivers. The control device 5 may be centralized in one location or distributed across multiple locations.

[0097] It should be noted that, when considering the various devices included in the die-casting machine 1, control device 5 can be understood as the control device for that device. For example, control device 5 can be understood as the control device for absorption device 2.

[0098] In this embodiment, the operation of the die-casting machine 1 (absorption device 2) can be substantially controlled by the control device 5. Therefore, for example, referring to... Figure 1 (a) ~ Figure 2 (b) the actions described, and refer to the following. Figures 5-8 Unless otherwise specified, the actions described can be achieved through the control of the control device 5. For convenience, the description of the implementation method sometimes omits the control of the control device 5 over various actions. It should be noted that some or all of the actions achieved through the control of the control device 5 can be achieved by the operator operating the input device (not shown) of the die-casting machine 1, or by manual operation.

[0099] (1.4. Other structures of the die-casting machine)

[0100] The die-casting machine DC with mold (or die-casting machine 1 or absorption device 2) can be equipped with various sensors. Furthermore, the control device 5 can control each part based on the detection values ​​of various sensors.

[0101] Examples of such sensors are given below. For example, although not specifically illustrated, a position sensor that detects the position of the plunger 21 and / or a sensor that detects the driving force of the drive unit 23 can be provided. Since velocity is obtained by differentiating the position, the position sensor can also be regarded as a velocity sensor. As a sensor for detecting the driving force of the drive unit 23, for example, in a configuration where the drive unit 23 has an injection cylinder, a pressure sensor that detects the pressure of the working fluid can be used.

[0102] A sensor that detects the position of the plunger 21 is used, for example, to control the injection speed (in other words, the speed of the plunger 21). A sensor that detects the driving force of the drive unit 23 is used to control the injection pressure (in other words, the pressure exerted by the plunger 21 on the molding material). However, as will be described later, in this embodiment, the pressure of the molding material can also be adjusted to the desired pressure using the absorption device 2 for localized pressurization, and control of the injection pressure is not necessary.

[0103] (2. Advancing / Retracting Components)

[0104] The die-casting machine DC with mold (or die-casting machine 1 or absorption device 2) can have one or more of any number of advance and retraction parts 41. Figure 1 (a) ~ Figure 2 (b)). In the configuration with multiple advancing and retracting parts 41, for example, it is possible to absorb fluctuating pressure at various positions of the mold 101, reducing the possibility of burr formation. In addition, when the absorbing device 2 is used for localized pressurization, it is easy to apply pressure evenly to the molten metal inside the mold 101. However, in the following description, for convenience, unless otherwise specified, the description will sometimes focus on one advancing and retracting part 41.

[0105] like Figure 1 As shown in (b), the shape of the advance / retractor 41 can be approximately pin-shaped with the advance / retract direction as its length (as illustrated in the example), or it can be non-pin-shaped. As an example of the latter, a block-shaped form with a diameter larger than the length of the advance / retractor 41 in the advance / retract direction can be given. Furthermore, the shape of the cross-section (the section orthogonal to the advance / retract direction) of the advance / retractor 41 can be circular or a shape other than circular. The dimensions of the advance / retractor 41 are also arbitrary.

[0106] The forward / reverse component 41 can be configured in the fixed mold 103 (as shown in the example) or in the moving mold 105. In the description of this embodiment, for convenience, the description is sometimes given with the forward / reverse component 41 configured in the fixed mold 103.

[0107] The retractable component 41 may, for example, slide (or abut) relative to the mold (fixed mold 103 or moving mold 105) in part or all. The rear end portion of the retractable component 41 (the portion connected to the cylinder 43) may be located outside the mold or entirely inside the mold. As an example of the latter, the rear end portion of the retractable component 41 may be positioned in the space formed by the mold base (not shown).

[0108] The advancing / retracting direction of the advancing / retracting component 41 can be any appropriate direction. For example, the advancing / retracting direction can be the mold opening / closing direction (…). Figure 1 (b) The left and right directions can also be directions that intersect (orthogonal or inclined) with the mold opening and closing directions. However, if the advancing and retreating direction is the mold opening and closing direction, the advancing and retreating component 41 can, for example, be separated from the molded part by the action of peeling the molded part from the mold on which the advancing and retreating component 41 is arranged.

[0109] The position of the advancing / retracting component 41 relative to the cavity 107 can be appropriately set. For example, as Figure 1 (a) or Figure 1 As shown in (b), the cavity 107 has: a product section 107a having a shape corresponding to the product shape; a flow channel 107e guiding molten metal from the sleeve 19 to the product section 107a; and an overflow section 107b for the remaining molten metal to flow into. The advance / retractor 41 may also be located on the inner surface of any of these spaces.

[0110] exist Figure 1 In example (a), the advancing / retracting component 41 protrudes from the inner surface of the overflow portion 107b into the cavity 107. Additionally, in Figure 1 In example (b), the fixed mold 103 has a recess 107c on the side of the moving mold 105 for the front end portion of the advancing / retracting member 41 to enter and exit. Of course, the fixed mold 103 may also not have such a recess 107c.

[0111] It should be noted that, unless otherwise specified, the following description sometimes uses the example of the advancing / retracting component 41 being located in the overflow portion 107b. In this configuration, compared to other configurations where the advancing / retracting component 41 is located in the cavity 107, the time when the forming material reaches the advancing / retracting component 41 is close to the time when fluctuating pressure is generated. Moreover, for ease of explanation, the timing of these two events is sometimes not distinguished.

[0112] The forward and backward limits of the retractable component 41 can be defined, for example, by providing a component or part (stop) that the retractable component 41 abuts on the mold 101 when it moves forward or backward, or by defining the driving limit of the cylinder 43. It should be noted that in the description of the embodiments, sometimes it is not specifically distinguished whether the driving limit of the retractable component 41 is defined by the retractable component 41 or the cylinder 43. Unless otherwise specified, and as long as there is no contradiction, the terms "driving limit," "forward limit," and "backward limit" of the retractable component 41 can be interchanged with the terms "driving limit," "forward limit," and "backward limit" of the piston 47. Furthermore, illustrations of the components defining the forward and backward limits are omitted.

[0113] (3. The cylinder and check valve of the absorption device)

[0114] (3.1. Operation of cylinder and check valve)

[0115] The action of the retracting component 41 being pushed back by the pressure of the molten metal 109 is as follows: Figure 3 As already described. In addition, for example, cylinder 43 and check valve 51 are connected via ports 45a and 45b of cylinder component 45. Figure 3 It supplies working fluid, etc., and can perform the following actions.

[0116] If equal hydraulic pressure is applied to both the head chamber 45h and the rod chamber 45r via ports 45a and 45b, the pressure-bearing area of ​​piston 47 in the head chamber 45h is larger than that in the rod chamber 45r, thus propelling piston 47 forward. At this time, check valve 51 is closed by the force of a spring (not shown), described later. And / or, as piston 47 advances, the pressure in the rod chamber 45r becomes higher than the pressure in the head chamber 45h, thereby closing check valve 51. This action can be used, for example, in the following... Figure 6 The action.

[0117] When working fluid is supplied to the rod-side chamber 45r via port 45b, it is permissible to supply fluid from the head-side chamber 45h to the reservoir 59 via port 45a. Figure 5 When the working fluid is discharged, the pressure in the rod-side chamber 45r becomes higher than the pressure in the head-side chamber 45h, thus closing the check valve 51. Additionally, the piston 47 retracts due to the pressure in the rod-side chamber 45r. It should be noted that the destination of the working fluid discharged from the head-side chamber 45h can also be other than the reservoir 59. This operation can be used, for example, in the following... Figure 7 The action.

[0118] If working fluid is supplied to the head chamber 45h via port 45a, and the working fluid is allowed to discharge from the rod chamber 45r to the reservoir 59 via port 45b, the piston 47 advances due to the pressure in the head chamber 45h. Even if the working fluid flows from the head chamber 45h to the rod chamber 45r via the check valve 51, the piston 47 continues to advance because the pressure-bearing area of ​​the piston 47 in the head chamber 45h is larger than that in the rod chamber 45r. Furthermore, if the pressure in the rod chamber 45r becomes greater than the pressure in the head chamber 45h as the piston 47 advances, the check valve 51 closes. In this case, the piston 47 also continues to advance. When the piston 47 reaches its forward limit, the working fluid supplied to the head chamber 45h is discharged to the reservoir 59 via the check valve 51 and the rod chamber 45r. This operation can be used, for example, in the following description. Figure 8 The action.

[0119] (3.2. Cylinder Structure)

[0120] The die-casting machine DC (or die-casting machine 1 or absorption device 2) with mold can have any number of cylinders 43, or more. However, unless otherwise specified in the description of the embodiments, the description is sometimes made with regard to one cylinder 43.

[0121] The number of forward / reverse components 41 driven by a cylinder 43 can be one (as illustrated in the example) or more than two. In the latter case, for example, in order to be analogous to a known ejection device, a plate-shaped component facing the forward / reverse direction of the forward / reverse component 41 can be connected to the cylinder 43, and multiple forward / reverse components 41 can be fixed to the plate-shaped component side by side. It should be noted that, in the description of this embodiment, for convenience, the illustrated method (one cylinder 43 driving one forward / reverse component 41) is used as an example.

[0122] The general structure of cylinder 43 is as described above. Cylinder component 45 is, for example, a generally cylindrical component. The cross-sectional shape of the interior of cylinder component 45 is, for example, circular. The external shape of cylinder component 45 can be a suitable shape such as a cuboid. Piston 47 is, for example, a generally cylindrical component capable of sliding axially inside cylinder component 45. Rod 49 is, for example, a generally cylindrical component. The diameter of rod 49 is smaller than the diameter of piston 47.

[0123] It should be noted that, for convenience, in the description of the embodiments, unless otherwise specified, the description is sometimes based on the premise that the cross-sectional shape of the piston 47 and the rod 49 is circular. Therefore, for example, based on the relationship between the diameter and area of ​​a circle, the description of the diameter of the cross-section and the description of the area of ​​the cross-section can be mutually referenced.

[0124] The dimensions of the piston 47 and rod 49 are arbitrary. In this embodiment, as can be understood from the operation described later, a large driving force is not required when the piston 47 is retracted by supplying working fluid from a hydraulic source (e.g., a pump or accumulator) to the rod-side chamber 45r. Alternatively, unlike the description of this embodiment, the operation of generating driving force by supplying working fluid from a hydraulic source to the rod-side chamber 45r may not be performed. Therefore, the ratio of the diameter of the rod 49 to the diameter of the piston 47 (<1) can be larger than that of a typical hydraulic cylinder. From another perspective, the diameters of the piston 47 and cylinder components 45 can be reduced to achieve miniaturization.

[0125] For example, the value obtained by dividing the pressure area of ​​piston 47 in rod-side chamber 45r by the pressure area of ​​piston 47 in head-side chamber 45h is generally about 4 / 5. In contrast, in cylinder 43, the above value can be set to 3 / 5 or less, or for example, it can be set to about 1 / 2 (e.g., 4 / 10 or more and 6 / 10 or less, or 9 / 20 or more and 11 / 20 or less). It should be noted that when the above value is 1 / 2, the driving force when a specified pressure (the same pressure) is applied to both rod-side chamber 45r and head-side chamber 45h is approximately equal to the driving force when the above specified pressure is applied only to rod-side chamber 45r (head-side chamber 45h is set to reservoir pressure).

[0126] Cylinder 43 may have a stop (reference numerals omitted) at a suitable position, such as between piston 47 and cylinder component 45. It should be noted that, for convenience, even with a stop between piston 47 and cylinder component 45, the piston 47 will still slide relative to cylinder component 45. Other components (e.g., accumulator 65) may also have stops at suitable positions. However, for convenience, reference numerals are sometimes omitted, and they are not specifically mentioned. Even with a stop, the sliding behavior is the same as with cylinder 43.

[0127] The piston 47 defines physical forward and backward limits (drive limits) by abutting against the front and rear ends (a concept including a stop not shown) inside the cylinder component 45. As mentioned above, these forward and / or backward limits may define the forward and / or backward limits of the retractable component 41, or they may not define them.

[0128] The piston 47 and rod 49 (which can also be considered as a single component) have a flow path 61 including a one-way valve 51. The shape of the flow path 61 is arbitrary, as long as it allows communication between the head-side chamber 45h and the rod-side chamber 45r. Figure 3In the example, flow path 61 has a first portion that axially passes through piston 47 and a second portion that extends radially from the first portion on rod 49. The number of second portions is arbitrary; for example, there may be one second portion or multiple second portions arranged radially. (As will be discussed later...) Figure 5 The figure represents a cross section along two second parts that have more than two second parts and extend to opposite sides of each other.

[0129] For example, such as Figure 1 As shown in (a), cylinder 43 is coaxially disposed with the retractable member 41 on the side opposite to cavity 107, and rod 49 is positioned with its side facing the retractable member 41. Cylinder member 45 remains stationary relative to fixed mold 103 (the mold on which the retractable member 41 is disposed). The front end of rod 49 is fixed to the rear end of retractable member 41.

[0130] The forward / reverse component 41 and the rod 49 can be fixed by an appropriate method. For example, the forward / reverse component 41 and the rod 49 can be fixed by a coupling. Figure 1 (a) Alternatively, an internal thread portion provided on one side of the rod 49 and the retractable member 41 can be screwed onto an external thread portion provided on the other side. Alternatively, theoretically, the retractable member 41 and the rod 49 can be integrally formed and fixed together. The fixing of the fixed mold 103 (the mold in which the retractable member 41 is configured) and the cylinder member 45 can also be performed by appropriate methods. For example, the cylinder member 45 can be fixed to the fixed mold 103 and / or the fixed template 13 by bolts, etc. Alternatively, at least a portion of the cylinder member 45 can be integrally formed with and fixed to the fixed mold 103.

[0131] (3.3. Structure of a one-way valve)

[0132] As described above, the position of the one-way valve 51 is arbitrary and not limited to the piston 47. For example, the one-way valve 51 may also be provided on the cylinder component 45, or on a cylinder fixed to the outer side of the cylinder component 45, or separately from the cylinder component 45. When a flow path 61 including the one-way valve 51 and a bypass circuit 53 different from the flow path 61 are provided, the length of the flow path 61 (e.g., the length along the centerline) may be shorter than the length of the bypass circuit 53. It should be noted that, unless otherwise specified, the description of the embodiments is sometimes based on the premise that the one-way valve 51 is provided on the piston 47.

[0133] The one-way valve 51 can have various structures, including those known to be located at the piston 47, except for its location at the piston 47. For example, although not specifically illustrated, the one-way valve 51 includes: a valve body comprising a valve flow path for the working fluid to flow from the head chamber 45h side to the stem chamber 45r side; and a valve core movable relative to the valve body. The valve core, for example, can block the valve flow path by abutting against a valve seat on the valve body from the stem chamber 45r side to the head chamber 45h side.

[0134] The one-way valve 51, for example, has a spring that presses the valve core against the valve seat. Therefore, when the force of the working fluid from the head chamber 45h side pushing the valve body exceeds the difference between the spring pressing the valve core and the working fluid from the stem chamber 45r side pushing the valve body, the valve body moves away from the valve seat. This allows flow from the head chamber 45h to the stem chamber 45r. Conversely, if this is not the case, flow from the stem chamber 45r to the head chamber 45h is prohibited. It should be noted that the spring may not be provided.

[0135] The valve body can be constructed, for example, by a suitable combination of multiple components with appropriate shapes. The component occupying most of the piston 47 can also constitute at least a part of the valve body. The valve flow path, for example, the portion on the head chamber 45h side relative to the valve seat and valve core, and the portion on the opposite side, can be located in the same straight line or intersect each other. The valve core can be, for example, a lifting valve composed of a conical portion and a cylindrical portion, or... Figure 3 The valve seat is spherical, as indicated by the attached reference numerals. The shape of the valve seat is also arbitrary.

[0136] Check valve 51 is not a pilot-operated check valve. In other words, check valve 51 always allows flow from the head chamber 45h to the stem chamber 45r and prohibits flow in the opposite direction (hereinafter, sometimes referred to as "allowing one-way flow"). However, check valve 51 can also be configured as a pilot-operated valve.

[0137] As described above, during the movement of piston 47 from the rod-side chamber 45r to the head-side chamber 45h, check valve 51 allows unidirectional flow. Alternatively, flow path 61 does not have a mechanism that allows unidirectional flow of check valve 51 only when piston 47 is at its forward limit (drive limit on the rod-side chamber 45r side) and / or its backward limit (drive limit on the head-side chamber 45h side) (e.g., a control valve combining check valve 51 with other check valves; see Patent Document 6). In other words, check valve 51 allows unidirectional flow when piston 47 is at any position within the range from the forward limit to the backward limit (always or for a specified period). However, check valve 51 may also allow unidirectional flow only within a specified range including the forward limit.

[0138] Strictly speaking, even in the case of a mechanism that allows unidirectional flow of the check valve 51 to be effective only when the piston 47 is at its drive limit, the unidirectional flow permission is effective not only when the piston 47 is at its drive limit, but also when the piston 47 is within a small distance from the drive limit. This small distance is, for example, less than the movable distance of the valve spool in a check valve different from the check valve 51, which is used to enable and disable the unidirectional flow permission. When unidirectional flow is allowed during the movement of the piston 47, the operation does not include allowing unidirectional flow only within such a small distance. The aforementioned small distance can also be referred to as the movable distance of the valve spool in the check valve 51.

[0139] Furthermore, for example, it lacks any components that restrict the flow from the head chamber 45h to the one-way valve 51. For instance, it does not have a throttling orifice or an overflow valve between the head chamber 45h and the one-way valve 51 (see Patent Document 5). Figure 3 The same applies to the one-way valve 51 and the stem-side chamber 45r. In another viewpoint, the flow path 61 connecting the head-side chamber 45h and the stem-side chamber 45r is configured as a valve with only the one-way valve 51. Furthermore, for example, in the flow path 61, the minimum area of ​​the cross-section on the head-side chamber 45h side and / or the stem-side chamber 45r side of the one-way valve 51 (the sum of the minimum areas in the case of multiple branched flow paths) is greater than the minimum area of ​​the cross-section within the one-way valve 51 (e.g., the area of ​​the gap between the valve seat and the valve core, or the opening area of ​​the port of a lift valve having a flow path). This is an example of a configuration without a throttling orifice.

[0140] However, for example, within the scope of the intended operation, there may be a portion where the cross-sectional area of ​​the flow path 61 is reduced, or there may be a valve other than the check valve 51. For example, an overflow valve may be provided, which prohibits flow from the head chamber 45h to the check valve 51 when the pressure of the molten metal is lower than the expected fluctuation pressure and the pressure in the head chamber 45h is lower than a predetermined threshold, and allows flow from the head chamber 45h to the check valve 51 when this is not the case.

[0141] (4. Hydraulic device of the absorption unit)

[0142] Figures 5-8 This is a diagram showing the structure of the absorption device 2. Figures 5-8 As described later in the explanation of the operation of the absorption device 2, different states are shown. In these figures, the flow path under relatively high pressure is represented by a thicker line than the other flow paths. Furthermore, the forward / reverse component 41 and the rod 49 are shown as a single, integrated component. For convenience, this can be understood as representing only one component, or it can be understood as actually being a single component.

[0143] The portion of the hydraulic system included in the absorption device 2, excluding cylinder 43 (which includes check valve 51 in this embodiment), is referred to as hydraulic device 63. Cylinder 43 and hydraulic device 63 can also be implemented separately (e.g., manufactured and / or circulated). In this case, unlike the description of the embodiment, only cylinder 43 or only hydraulic device 63 can be considered as a fluctuation pressure absorption device. Additionally, the combination of mold 101, advance / retract component 41, and cylinder 43 can circulate independently of hydraulic device 63 as a fluctuation pressure absorption mold. Unlike this embodiment, in the case where check valve 51 is not built into cylinder 43, check valve 51 can be manufactured and / or circulated independently of cylinder 43; in this case, check valve 51 can also be understood as a component of hydraulic device 63.

[0144] The hydraulic device 63 generally comprises the following three parts: A structure related to the flow of working fluid from the head chamber 45h to the accumulator 65 accompanying the retraction of the advance / retractor 41. A structure related to supplying working fluid from the hydraulic source (pump 57 in the illustrated example) to the cylinder 43 and discharging working fluid from the cylinder 43 to the reservoir 59. Other structures. These structures will be described in turn below.

[0145] (4.1. Structure from cylinder to accumulator)

[0146] Accumulator 65 is connected to head chamber 45h via ACC flow path 67A. ACC flow path 67A has an ACC valve 69 that controls the flow in ACC flow path 67A. ACC valve 69 helps reduce the possibility of working fluid flowing into accumulator 65, for example, when the piston 47 is advanced due to the supply of working fluid from pump 57 to head chamber 45h. In the illustrated example, ACC valve 69 is a pilot-operated valve. The introduction of pilot pressure is controlled by pilot valve 71. The specific structure of each component is described below.

[0147] The accumulator 65 can take various forms, such as weight-type, spring-type, pneumatic-type, piston-type, or bladder-type. In a weight-type accumulator, the working fluid is pressurized by the gravity of a counterweight. In a spring-type accumulator, the working fluid is pressurized by the restoring force of a spring. In a pneumatic-type accumulator, the compressed gas is in direct contact with the working fluid, thus pressurizing it. In a piston-type accumulator, the compressed gas pressurizes the working fluid via a piston. In a bladder-type accumulator, the compressed gas pressurizes the working fluid via a flexible bladder (diaphragm). In pneumatic, piston, and bladder-type accumulators, the gas is, for example, air or an inert gas (e.g., nitrogen).

[0148] exist Figure 5In the illustration, a piston-type accumulator is shown as accumulator 65. Although not specifically labeled, accumulator 65 has a cylinder component and a piston housed within it. The interior of the cylinder component is divided into a liquid chamber for containing liquid and a gas chamber for containing gas. Accumulator 65 uses the pressure of compressed gas (e.g., nitrogen or air) in the gas chamber to pressure the working fluid in the liquid chamber. The liquid chamber is connected to ACC flow path 67A.

[0149] The structure of ACC valve 69 can be various, for example, as long as it can prevent flow from one side of head chamber 45h to the side of accumulator 65. In the illustrated example, ACC valve 69 is composed of a logic valve controlled by the pressure (pilot pressure) introduced from flow path 67B.

[0150] Specifically, in the ACC valve 69 shown in the figure, a spring (not shown) applies a restoring force to the valve core (not shown) toward the closed position (the position where the ACC valve 69 is closed). The pressure in the ACC flow path 67A (or, in other views, the head chamber 45h) and the pressure in the accumulator 65 both act as forces that move the valve core toward the open position. Therefore, when no pilot pressure is introduced, the sum of the forces exerted on the valve core by the pressure in the ACC flow path 67A and the pressure in the accumulator 65 toward the open position (the force generated by the pressure of the other when the force generated by one pressure is 0) exceeds the aforementioned restoring force, thereby opening the ACC valve 69. Furthermore, when a pilot pressure is introduced, the sum of the force exerted on the valve core by the pilot pressure toward the closed position and the aforementioned restoring force exceeds the force exerted on the valve core toward the open position, thereby closing the ACC valve 69. Other structures besides the illustrated example of the ACC valve 69 include, for example, a check valve, a switching valve, a flow control valve, a pressure control valve, or a solenoid valve.

[0151] Pilot valve 71 is used to introduce pilot pressure into ACC valve 69 and to stop it. Its structure can be various. Figure 5 The diagram illustrates a 4-port, 2-position switching valve. However, one of the 4 ports is blocked and becomes unused. In the rectangular position on the right side of the diagram, pilot valve 71 connects flow path 67B, which is connected to the pilot port of ACC valve 69, and the reservoir 59. This stops the introduction of pilot pressure into ACC valve 69. Alternatively, in the rectangular position on the left side of the diagram, pilot valve 71 connects flow path 67B and pump 57. This introduces pilot pressure into ACC valve 69. The actuation method of pilot valve 71 is arbitrary. Figure 4 The diagram illustrates a combination of a spring that moves the pilot valve 71 to the position of the rectangle on the right and a solenoid that moves the pilot valve 71 to the position of the rectangle on the left.

[0152] The ACC flow path 67A branches off towards the cylinder 43 side, corresponding to the multiple cylinders 43. It should be noted that, in the case of multiple cylinders 43, a different arrangement may be made, with one accumulator 65 corresponding to each cylinder 43. Alternatively, as shown in the example, a structure may be provided where multiple cylinders 43 are connected to a single accumulator 65.

[0153] For example, in the ACC flow path 67A between the head chamber 45h and the accumulator 65, only the ACC valve 69, controlled by the control device 5, is present; no other valves are present. It should be noted that the ACC flow path 67A may or may not have valves that are not controlled by the control device 5 (e.g., manually operated valves). Furthermore, for example, in the ACC flow path 67A, the minimum cross-sectional area of ​​the portion other than the ACC valve 69 (in the case of branches, the sum of the minimum areas) is larger than the minimum cross-sectional area within the ACC valve 69. With this structure, the pressure loss of the ACC flow path 67A is reduced.

[0154] The various flow paths of the hydraulic device 63 (including flow paths other than ACC flow path 67A) can be of suitable structure. For example, each flow path can be constructed by a pipe made of a rigid body, a flexible hose, a block forming the flow path, and / or a combination thereof.

[0155] (4.2. Structure from pump and reservoir to cylinder)

[0156] The hydraulic unit 63 includes the previously mentioned pump 57, reservoir 59, and switching valve 55. Additionally, the hydraulic unit 63 includes a check valve 73 to prevent backflow into the pump 57. The specific structures of each element are described below.

[0157] The pump 57 and / or the reservoir 59 may be shared by a hydraulic device other than the absorption device 2 of the die-casting machine 1 (e.g., the hydraulic device of the injection device 9), or they may not be shared. It should be noted that the pump 57 and the reservoir 59 may also be shared by multiple die-casting machines 1, etc. In addition, the pump 57 and the reservoir 59 may also be not considered as components of the die-casting machine 1 (hydraulic device 63).

[0158] The pump 57 and the liquid reservoir 59 can have various structures, such as those known to the public. The pump 57 can be driven as needed or always driven. For example, the pump 57 can arbitrarily adjust the supply pressure. This adjustment can be achieved, for example, by controlling the rotational speed of the motor 75 that drives the pump 57. The motor 75 can be, for example, an AC servo motor or controlled by an inverter. The liquid reservoir 59 is, for example, an atmospheric-open type. In other words, the pressure in the liquid reservoir is approximately atmospheric pressure. Therefore, the pressure in the flow path connected to the liquid reservoir 59, etc., is theoretically approximately atmospheric pressure.

[0159] The switching valve 55 is configured as a 4-port, 3-position switching valve. In the rectangular position shown on the left side of the figure, the switching valve 55 connects the pump 57 to the head-side chamber 45h and the reservoir 59 to the rod-side chamber 45r. This allows, for example, the piston 47 to move forward. Furthermore, in the rectangular position shown on the right side of the figure, the switching valve 55 connects the pump 57 to the rod-side chamber 45r and the reservoir 59 to the head-side chamber 45h. This allows, for example, the piston 47 to move backward. Additionally, in the rectangular position shown in the center of the figure, as described above... Figure 3 As already described, the rod-side chamber 45r, the head-side chamber 45h, and the pump 57 are interconnected.

[0160] The driving method of switching valve 55 is arbitrary. Figure 5 The diagram illustrates a combination of a spring that moves the switching valve 55 to the position of the rectangle in the center of the diagram, and a solenoid that moves the switching valve 55 to the positions of the rectangles on the right and left sides of the diagram. The position of the rectangle in the center of the diagram represents the neutral position when the solenoid is not actuated.

[0161] The flow path (notation omitted) connecting the head chamber 45h to the switching valve 55 and the ACC flow path 67A connecting the head chamber 45h to the accumulator 65 share a portion of the head chamber 45h side. In another view, the two flow paths are interconnected. Therefore, for example, when the switching valve 55 is in the rectangular state shown on the left side of the figure, the pump 57 helps to apply pressure to the ACC flow path 67A, thereby helping to open the ACC valve 69 or to store pressure in the accumulator 65.

[0162] The check valve 73 allows flow from pump 57 but prevents flow in the opposite direction. A portion of the flow path connecting pump 57 to switching valve 55 (notation omitted) and the flow path connecting pump 57 to pilot valve 71 (notation omitted) are shared on the pump 57 side. The check valve 73 is located in this shared portion.

[0163] (4.3. Other structures of the hydraulic device)

[0164] The hydraulic unit 63 has a discharge path (not shown in the figures) connecting the ACC flow path 67A and the reservoir 59, and a discharge valve 79 located in this flow path. The discharge path, for example, facilitates the discharge of working fluid from the ACC flow path 67A and components connected to it (e.g., head chamber 45h and / or accumulator 65) during maintenance of the absorption unit 2. During the molding cycle, the discharge valve 79 remains in a state that blocks the ACC flow path 67A from the reservoir 59 (the rectangular state on the left side of the figure).

[0165] The hydraulic device 63 has a pressure sensor 77 that detects the pressure of the head chamber 45h. This pressure sensor 77 is referenced, for example, when adjusting the pressure of the head chamber 45h during pressure fluctuations or during partial pressurization. That is, the pressure sensor 77 is used for pressure feedback control. The pressure sensor 77 can detect pressure at any location as long as it can substantially detect the pressure of the head chamber 45h. In the illustrated example, the pressure sensor 77 detects the pressure in the ACC flow path 67A on the side closer to the head chamber 45h than the ACC valve 69. The structure of the pressure sensor 77 is also arbitrary.

[0166] The hydraulic unit 63 has a temperature sensor 81 for detecting the temperature of the mold 101. This temperature sensor 81, for example, helps to set a target pressure for the head chamber 45h (and / or accumulator 65) when absorbing fluctuating pressure. Specifically, if the temperature of the mold 101 changes, the flow of the molten metal 109 also changes, and consequently the magnitude of the fluctuating pressure also changes. Generally, when the temperature of the mold 101 rises, the fluctuating pressure increases. Therefore, for example, based on the temperature rise detected by the temperature sensor 81, the aforementioned target pressure (or, in other views, the degree to which the hydraulic unit 63 absorbs fluctuating pressure) is increased. The structure and position of the temperature sensor 81 are arbitrary. For example, temperature sensors for detecting the temperature of the mold 101 in other applications are known, and the structure and position of the temperature sensor 81 can be the same as such temperature sensors.

[0167] The relative relationship between the detected temperature (and / or its change) and the target pressure (and / or its change) can be appropriately set based on experiments, etc. The control device 5, for example, stores a mapping diagram corresponding to the temperature and the target pressure, which is referred to to set the target pressure corresponding to the detected value of the temperature sensor 81. The mapping diagram can be created by the manufacturer and user of the hydraulic device 63, or it can be created based on the temperature and pressure fluctuations detected by the control device 5 or a server communicating with the control device 5 during trial operation and / or past forming cycles.

[0168] Although not specifically illustrated, the absorption device 2 may also have a position sensor that directly detects the position of the advancing / retracting member 41 or the rod 49. Additionally, the absorption device 2 may also have a flow sensor that detects the flow rate of the working fluid discharged from the rod-side chamber 45r. Such a position sensor or flow sensor, for example, helps in detecting the position and / or movement of the advancing / retracting member 41. The absorption device 2 may also have a pressure sensor that detects the pressure in the rod-side chamber 45r. This pressure sensor, for example, together with a pressure sensor 77 that detects the pressure in the head-side chamber 45h, helps in calculating the pressure exerted by the advancing / retracting member 41 on the molten metal.

[0169] (5. Operation of the injection device)

[0170] Figure 9 This is a diagram used to illustrate the injection process. In this diagram, the horizontal axis represents time t, with later time points further to the right. The vertical axis on the left represents velocity V, with higher values ​​indicating higher velocities. The vertical axis on the right represents pressure P, with higher values ​​indicating higher pressure.

[0171] Line LnV represents the time-varying change in injection speed (the speed of plunger 21). Line LnP represents the time-varying change in injection pressure. Here, injection pressure is the pressure exerted by plunger 21 on the molten metal. It should be noted that the speed or pressure represented by lines LnV and LnP can be understood as representing target values ​​or actual values. Furthermore, the waveforms shown by these lines are merely one example.

[0172] For example, the die-casting machine 1 sequentially performs low-speed injection (times t0 to t1), high-speed injection (times t1 to t2), and pressurization and holding (times around t2). That is, as shown in line LnV, in the initial stage of injection, the die-casting machine 1, from the viewpoint of preventing air from being trapped in the molten metal, operates the plunger 21 at a relatively low speed (speed V). L The die-casting machine 1 injects the plunger 21 at a low speed, as shown in line LnV, from the viewpoint of filling the molten metal no later than the solidification of the molten metal. H The high-speed injection proceeds forward. Next, as shown in line LnP, from the viewpoint of eliminating shrinkage cavities, the die-casting machine 1 performs a pressurization process to increase the pressure applied to the molten metal through the plunger 21. Afterwards, as shown in line LnP, the die-casting machine 1 maintains the casting pressure Pc (final pressure) obtained through the pressurization process.

[0173] If the above steps are supplemented, the injection pressure will be relatively low during low-speed injection (times t0 to t1). It should be noted that... Figure 9 For simplicity, the injection pressure during low-speed injection is shown as extremely low and is omitted from the diagram. Then, when high-speed injection begins (time t1), the injection pressure increases. Furthermore, if the filling of molten metal is largely complete (around time t2), the molten metal loses its place, thus the injection speed decreases sharply, and the injection pressure increases sharply. It should be noted that deceleration injection to reduce the injection speed is also possible. However, in this embodiment, the pressure fluctuations are absorbed by the absorption device 2, so the necessity for deceleration injection is low. The injection pressure may also increase simply due to the loss of molten metal. That is, no special action for pressurization is required. During pressure holding, the injection speed is approximately zero.

[0174] Pressurization can be performed in various ways. For example, pressurization can be performed after speed-controlled injection into the head chamber 23h of the injection cylinder, which serves as the drive unit 23. Figure 1(a) Supply the working fluid and perform pressure control. Alternatively, pressurization can be achieved by supplying the working fluid to the head chamber 23h from a different accumulator than the one used to supply the working fluid to the head chamber 23h during injection. Additionally, pressurization can also be achieved by supplying the working fluid to the head chamber 23h from a different accumulator than the one used to supply the working fluid to the head chamber 23h during injection. Figure 1 (a) In the example injection cylinders of different pressurized types, working fluid is supplied to the pressurization cylinder that increases the pressure in the head chamber 23h. Figure 9 The example illustrates the use of a booster injection cylinder, where the casting pressure Pc is higher than the pressure P1 (around time t3) obtained by applying hydraulic pressure to the head chamber 23h.

[0175] Line Ln1 represents the minimum pressure required to generate burrs (the burr generation limit curve). This pressure is approximately proportional to √t. Line Ln0 represents a portion of the injection pressure that may occur without the absorption device 2. As shown in the figure, without the absorption device 2, fluctuating pressure occurs upon completion of filling, and the injection pressure exceeds the burr generation limit curve, potentially causing burrs. In this embodiment, by reducing such fluctuating pressure, it becomes easier, for example, to keep the pressure near completion of filling (around time t3) below the burr generation limit curve, or to keep the subsequent pressure close to the burr generation limit curve.

[0176] (6. Operation of the absorption device)

[0177] For example, the die-casting machine 1 repeatedly performs forming cycles. Figures 5-8 This represents a series of actions performed by the absorption device 2 during each forming cycle. The actions (states) of the absorption device 2 are according to... Figure 5 , Figure 6 , Figure 7 as well as Figure 8 The order of the changes is as follows. Specifically, it is as follows.

[0178] (6.1. State before absorbing fluctuation pressure)

[0179] Figure 5 This indicates the state of the molten metal when it reaches the advancing / retracting component 41. Figure 5 In addition to the molten metal 109 reaching the advancing / retracting component 41, Figure 5 This can be understood as representing the state of the molten metal before it reaches the advancing / retreating component 41 (e.g., before).

[0180] Before the molten metal 109 reaches the advance / retractor 41, the control device 5 controls the hydraulic device 63 (or ACC valve 69 in other views) to allow flow between the ACC flow path 67A (or the head chamber 45h of cylinder 43 in other views) and the accumulator 65. Specifically, the control device 5 sets the pilot valve 71 to the rectangular state shown on the right side of the figure, stopping the introduction of pilot pressure to the ACC valve 69. Additionally, the control device 5... Figure 3 The bypass circuit 53 shown is activated. Specifically, the control device 5 sets the switching valve 55 to the position of the rectangle in the center of the figure.

[0181] The pressure in the head chamber 45h is adjusted to a predetermined target pressure. This adjustment is achieved, for example, through feedback control of the pump 57 (motor 75) based on the detection value of the pressure sensor 77 by the control device 5. As mentioned above, the target pressure can be set based on the detection value of the temperature sensor 81. In this case, the target pressure can be set, for example, for each molding cycle or for each predetermined number of molding cycles. The temperature of the mold 101 varies during the molding cycle. The temperature used to set the target pressure can be the temperature at any time during the molding cycle or the average value over a predetermined period. Of course, the target pressure can also be constant regardless of the temperature of the mold 101.

[0182] As a result of the control described above, equal pressure is applied to the rod-side chamber 45r and the head-side chamber 45h in cylinder 43. Furthermore, the piston 47 and the forward / reverse mechanism 41 are stopped at their forward limit. The pressure in the accumulator 65 can be approximately equal to or higher than the pressure in the head-side chamber 45h. In the former case, the piston of the accumulator 65 can be located near the drive limit on the liquid chamber side, or it can be moved a certain distance away from the drive limit towards the gas chamber side. In the latter case, the piston of the accumulator 65 is located at the drive limit on the liquid chamber side.

[0183] The specific value of the target pressure is arbitrary, as long as it is below the force required to retract the retracting member 41 by the molten metal 109 when a specified pressure fluctuation occurs. For example, the target pressure can be less than 1 MPa or more than 1 MPa. As an example, the target pressure can be adjusted in 0.1 MPa units within the range of 1 MPa to 5 MPa. The specified magnitude of the fluctuation pressure can also be conceived by any of the manufacturer, operator, and control device 5 of the absorption device 2. Similarly, the target pressure can also be set by any of the manufacturer, operator, and control device 5 of the absorption device 2.

[0184] (6.2. Action of absorbing fluctuating pressure)

[0185] When molten metal 109 is injected into the cavity 107 of mold 101 via injection device 9, molten metal 109 reaches the advancing / retracting part 41. Furthermore, when molten metal 109 pushes the advancing / retracting part 41 rearward (… Figure 5 When the pressing force (on the right side) exceeds the force of the cylinder 43 pressing the forward / backward component 41 forward, such as Figure 2 (a) and Figure 2As shown in (b), the advance / retreat component 41 retracts. At this time, as described above, flow occurs from the head side chamber 45h to the rod side chamber 45r via the one-way valve 51, flow occurs in the bypass circuit 53, and flow occurs from the head side chamber 45h to the accumulator 65. In addition, the backflow of the working fluid discharged from the head side chamber 45h to the pump 57 side is restricted by the one-way valve 73.

[0186] As the working fluid flows from the head chamber 45h side into the accumulator 65, the pressure in the accumulator 65 increases. That is, the force of the cylinder 43 pressing the retractable member 41 forward increases. When this increased force balances the force of the molten metal pressing the retractable member 41 backward, the retractable member 41 stops. Alternatively, the retractable member 41 stops because the retractable member 41 or the piston 47 reaches its retraction limit. It should be noted that, unlike the description here, the retractable member 41 may also stop when the piston of the accumulator 65 reaches its upper limit (the drive limit on the gas chamber side). In addition, as can be seen from the description of the local pressurization operation below, the retractable member 41 may also begin to advance before naturally stopping (local pressurization) as described above.

[0187] (6.3. Local pressure application)

[0188] Figure 6 This indicates the state during localized pressurization. The control device 5 controls the hydraulic device 63 to perform localized pressurization by advancing the retracting member 41 at an appropriate time after the retracting member 41 begins to retract. Specifically, for example, the control device 5 controls the ACC valve 69 to prevent flow from the ACC flow path 67A to the accumulator 65. That is, the control device 5 sets the pilot valve 71 to the state shown on the left side of the figure. Furthermore, the control device 5 controls the pump 57 (motor 75) to apply a pressure to the cylinder 43 higher than the pressure immediately after absorbing the pressure fluctuation.

[0189] When the retractable component 41 moves forward, feedback control based on the pressure sensor 77 can be performed. The target value of the pressure exerted by the retractable component 41 on the molten metal 109 can be a constant value or it can be set to rise along a predetermined pressure curve (a curve depicted in a graph with time on the horizontal axis and pressure on the vertical axis). Alternatively, unlike the description here, the retractable component 41 can also be position-controlled based on a sensor (not shown) that detects the position of the retractable component 41.

[0190] After localized pressurization begins, the retractable member 41 stops, for example, at a position where the force exerted by the cylinder 43 pressing the retractable member 41 forward is balanced by the force exerted by the molten metal pressing the retractable member 41 backward. Thus, the retractable member 41 applies a pressure to the molten metal specified by the pressure applied to the cylinder 43. However, contrary to the description herein, the retractable member 41 may also reach its forward limit before the aforementioned balance is achieved.

[0191] The pressure ultimately applied to the molten metal by the advancing / retracting component 41 is arbitrary. For example, this pressure is relative to the pressure ultimately applied to the molten metal by the plunger 21 ( Figure 9 The pressure Pc can be lower, equal to, or higher. It should be noted that due to the solidification of molten metal, Pascal's principle in molten metal does not strictly apply. Therefore, for example, even if the locally applied pressure is higher than the pressure Pc, as long as the difference is not too large, the plunger 21 will not retract.

[0192] Furthermore, the target value of the pressure applied by pump 57 to cylinder 43 can also be appropriately set. As an example, this target pressure value can be set and changed in units of 0.1 MPa within a range of less than 16 MPa.

[0193] The timing at which the control device 5 begins local pressurization can be set, for example, to a period when appropriate conditions are met, or to a period of time after a predetermined time has elapsed since the conditions were met. That is, the timing of starting local pressurization can be determined based on appropriate conditions.

[0194] The above conditions can be set, for example, by a position sensor (not shown) detecting the retraction of the forward / retractable component 41. This retraction detection can be the detection of whether the forward / retractable component 41 has retracted, the detection of the retraction amount reaching a predetermined amount, or the detection of the forward / retractable component 41 retracting to a predetermined position. It should be noted that when the retraction amount is relatively small and the predetermined position is close to the forward limit, it can be considered that the retraction of the forward / retractable component 41 has been detected.

[0195] The conditions that trigger the initiation of localized pressurization can also be conditions other than the detection of the retraction of the advance / retraction member 41. For example, the aforementioned condition could also be that a predetermined time has elapsed since the start of injection from the injection device 9. Alternatively, for example, the molten metal reaching the predetermined position can be detected by methods other than the detection of the retraction of the advance / retraction member 41 (e.g., an energizing sensor, a temperature sensor, or a pressure sensor).

[0196] (6.4. Spraying action)

[0197] When the molten metal solidifies, the control device 5 terminates the local pressurization of the advance / retractor 41. The control device 5 can appropriately determine whether the molten metal has solidified. For example, it can determine whether the solidification of the molten metal has occurred based on whether a predetermined time has elapsed from an appropriate time point (e.g., the injection start time point or the local pressurization start time point).

[0198] When the local pressurization ends, the control device 5 may not simply return the state of the absorption device 2 to the state before absorbing the pressure fluctuation. Figure 5Instead of retracting the piston 47 to its original state, the retracting component 41 is temporarily retracted. This retraction can, for example, continue until the retracting component 41 and / or the piston 47 reach their retraction limit. The retraction of the retracting component 41 can, for example, facilitate cooling and / or venting based on the discharge of working fluid from the head chamber 45h, or facilitate the spraying of the sliding portion of the retracting component 41 in the mold 101. During spraying, for example, blowing (cleaning) and / or blowing of a release agent can be performed.

[0199] Figure 7 This indicates that the forward / reverse component 41 is in a backward state as described above.

[0200] Control device 5, for example, sets switching valve 55 to the rectangular state shown on the right side of the figure. As a result, hydraulic pressure from pump 57 is supplied to the rod-side chamber 45r, and the head-side chamber 45h becomes the reservoir pressure. Consequently, piston 47 retracts, and consequently, the advance / retractor 41 retracts. The pressure applied by pump 57 to rod-side chamber 45r when the advance / retractor 41 retracts can be set to an appropriate magnitude. For example, this pressure can be lower, equal to, or higher than the pressure applied when the advance / retractor 41 is idle in its initial position (e.g., forward limit) before injection begins. As an example, the pressure of pump 57 can be set in units of 0.1 MPa within the range of 16 MPa or less.

[0201] When the retracting component 41 is moved backward, the ACC valve 69 can be opened or closed. In the illustrated example, it is set to the former. That is, the pilot valve 71 is in the state shown on the right side of the figure, and no pilot pressure is introduced into the ACC valve 69. Therefore, the accumulator 65 discharges the working fluid from the liquid chamber to the reservoir 59. At this time, the piston of the accumulator 65 may or may not reach the drive limit on the liquid chamber side (for example, the ACC valve 69 may be closed before reaching it). In other views, the pressure of the accumulator 65 may be lower than the pressure before absorbing the fluctuation pressure, or it may be set to the same pressure as the pressure before absorbing the fluctuation pressure (for example, the ACC valve 69 may be closed when the pressure before absorbing the fluctuation pressure is obtained).

[0202] (6.5. Preparatory actions for absorbing fluctuating pressure)

[0203] Figure 8 Indicates to be used to become Figure 5 The system is in a ready-to-go state. In this state, the control device 5 sets the switching valve 55 to the rectangular position shown on the left side of the figure. That is, the pump 57 is connected to the head chamber 45h, and the rod chamber 45r is connected to the reservoir 59. Then, working fluid is supplied from the pump 57 to the head chamber 45h. As a result, the piston 47 advances. At this time, the working fluid in the rod chamber 45r is discharged into the reservoir 59. After that, the piston 47 reaches its forward limit.

[0204] The rectangular state on the left side of the diagram for the switching valve 55 can end when the piston 47 reaches its forward limit, or it can continue until a predetermined termination condition is met after reaching the forward limit. In the latter case, the working fluid supplied to the head chamber 45h is discharged to the reservoir 59 via the check valve 51 and the rod chamber 45r. Thus, for example, when the piston 47 reaches its forward limit, the working fluid remaining in the rod chamber 45r can also be discharged. In addition, for example, the cylinder 43 can be cooled by allowing the working fluid to flow to the head chamber 45h and the rod chamber 45r. The aforementioned termination condition can be, for example, from becoming Figure 8 The time elapsed from the start of the piston's forward movement to its maximum, or from the moment the piston reaches its forward limit at position 47, is considered to be approximately 2 seconds. The length of this specified time is arbitrary; for example, it is around 2 seconds.

[0205] When the advance / retreat component 41 is advanced as described above (and / or at its advance limit), the ACC valve 69 can be opened or closed. In the illustrated example, it is set to the latter. That is, the pilot valve 71 is in the state shown on the left side of the figure, introducing pilot pressure into the ACC valve 69.

[0206] The magnitude of the pressure applied by pump 57 to head chamber 45h when advancing the retractable component 41 (and / or when it is at its advance limit) is arbitrary. For example, this pressure is relative to the pressure applied when the forming material in the waiting mold reaches the retractable component 41. Figure 5 Pump 57 imparts a pressure of 45h to the head chamber, which can be lower, equal, or higher. The specific value is arbitrary. As an example, the pressure of pump 57 can be set in 0.1MPa units within a range of 5MPa to 16MPa.

[0207] After the forward / reverse component 41 reaches its forward limit, when the specified conditions are met, the control device 5 causes the absorption device 2 to become... Figure 5 The state. It should be noted that becoming Figure 5 The timing of this state is arbitrary, as long as it occurs before the molten metal reaches the advancing / retracting component 41. For example, this moment could be before the plunger 21 begins to advance or after the plunger 21 begins to advance.

[0208] (7. Summary of the first implementation method)

[0209] As described above, the fluctuation pressure absorption device 2 of the embodiment has a one-way valve 51 connected to a hydraulic cylinder 43. The cylinder 43 has a rod 49, a piston 47, and a cylinder component 45. The rod 49 is fixed to a retracting component 41 that can move forward into the mold (mold 101) and backward to the opposite side. The piston 47 is fixed to the rod 49. The cylinder component 45 houses the piston 47. The interior of the cylinder component 45 is divided by the piston 47 into a rod-side chamber 45r where the rod 49 is located and a head-side chamber 45h on the opposite side. The one-way valve 51 allows flow from the head-side chamber 45h to the rod-side chamber 45r and prohibits flow in the opposite direction as the retracting component 41 retracts due to the pressure of the forming material (molten metal 109) in the mold 101, thereby moving the piston 47 from the rod-side chamber 45r to the head-side chamber 45h.

[0210] In another view, the forming machine (die casting machine 1 or die casting machine DC with mold) of the embodiment has an absorption device 2, a mold closing device 7 for holding the mold 101, and an injection device 9 for injecting forming material (molten metal 109) into the mold 101 as described above.

[0211] Therefore, for example, as described in the summary of the embodiments, when the retracting piston 47 is retracted due to the applied pressure to the retracting member 41, the working fluid in the head-side chamber 45h can be replenished to the rod-side chamber 45r by the pressure generated in the head-side chamber 45h. As a result, the delay time between the retraction of the retracting member 41 and the piston 47 and the instantaneous pressure rise can be shortened, effectively absorbing the pressure fluctuation. By absorbing the pressure fluctuation, the possibility of burr formation can be reduced. In other viewpoints, by controlling the magnitude of the pressure fluctuation, the necessary and sufficient pressure can be applied to the molten metal 109, reducing the formation of porosity. That is, the quality of the product is improved.

[0212] Furthermore, for example, if the one-way valve 51 is not provided and the rod-side chamber 45r and the head-side chamber 45h are simply connected, when working fluid is supplied to the rod-side chamber 45r, the working fluid flows from the rod-side chamber 45r to the head-side chamber 45h. On the other hand, the pressure-bearing area of ​​the rod-side chamber 45r of the piston 47 is smaller than that of the head-side chamber 45h. Therefore, it is impossible to perform the action of retracting the piston 47. Figure 7 However, in this embodiment, because a one-way valve 51 is provided, the piston 47 can be retracted. As a result, for example, spraying can be performed.

[0213] Furthermore, since a one-way valve 51 (or flow path 61 in other views) is provided, a reference can be made. Figure 8The operation is described below. Specifically, by supplying working fluid to the head chamber 45h while connecting the rod chamber 45r to the reservoir 59, the working fluid can flow to both the head chamber 45h and the rod chamber 45r. This allows for cooling or venting of the cylinder 43. This operation does not require a complex mechanism that only allows flow in one direction when the forward or backward limits are reached.

[0214] The one-way valve 51 may be included in the piston 47. In other views, the flow path 61, which includes the one-way valve 51 and connects the head side chamber 45h and the rod side chamber 45r, may be provided in the piston 47 and the rod 49 (or only the piston 47).

[0215] In this case, for example, compared to other methods (such as including a one-way valve 51 in a block fixed to the outer side of the cylinder component 45), it is easier to shorten the flow path 61. On the other hand, the working fluid generally has a certain degree of compressibility, and a time delay occurs from the retraction of the piston 47 until the working fluid is supplied to the head side chamber 45h to the rod side chamber 45r, which is equivalent to the length of the flow path 61. Therefore, by shortening the flow path 61, the effect of improving the aforementioned responsiveness is enhanced.

[0216] The absorption device 2 may also have a bypass circuit 53. The bypass circuit 53 can independently connect the rod-side chamber 45r and the head-side chamber 45h with the flow path 61 containing the one-way valve 51 during the process in which the piston 47 moves from the rod-side chamber 45r to the head-side chamber 45h by retracting the advancing member 41 due to the pressure of the molten metal 109 in the mold 101.

[0217] In this case, the working fluid flows from the head side chamber 45h to the rod side chamber 45r via both the flow path 61 and the bypass circuit 53, thus improving, for example, the responsiveness to the aforementioned fluctuation pressure.

[0218] The absorption device 2 may also include a switching valve 55 that switches the connection relationship between the rod-side chamber 45r, the head-side chamber 45h, the hydraulic source (pump 57), and the reservoir 59. The switching valve can switch between a first state and a third state. In the first state ( Figure 5 In the first state (the rectangle in the center of the reference numerals indicating the switching valve 55), the rod-side chamber 45r, the head-side chamber 45h, and the pump 57 are interconnected. In the second state (the rectangle on the right), the rod-side chamber 45r and the pump 57 are interconnected, and the head-side chamber 45h and the reservoir 59 are interconnected. In the third state (the rectangle on the left), the rod-side chamber 45r and the reservoir 59 are interconnected, and the head-side chamber 45h and the pump 57 are interconnected. The bypass circuit 53 is configured by switching the switching valve 55 to the first state.

[0219] Therefore, by constructing a bypass circuit 53 using a structure that supplies working fluid from pump 57 to cylinder 43 to drive piston 47, the responsiveness to the aforementioned fluctuating pressure is improved. As a result, the structure is simplified. Furthermore, since not only are the rod-side chamber 45r and head-side chamber 45h connected, but also connected to pump 57, a certain level of pressure can be applied to both the rod-side chamber 45r and head-side chamber 45h by pump 57 while waiting for molten metal 109 to reach the retraction member 41. As a result, the possibility of negative pressure being generated in rod-side chamber 45r when piston 47 retracts along with the retraction member 41 is further reduced. Consequently, the effect of improving responsiveness is further enhanced.

[0220] The absorption device 2 may also have a control device 5. The control device 5 may switch valve 55 to a third state after the retraction component 41 retracts due to the pressure of the forming material (molten metal 109) in the mold (mold 101) and before the molten metal 109 in the mold 101 reaches the retraction component 41 in the next forming cycle. Figure 8 The rectangle on the left in the symbol representing switching valve 55.

[0221] In this case, for example, as referenced Figure 8 As explained, advancing the advance / retractor 41 prepares the device for absorbing the fluctuating pressure during the next forming cycle. Furthermore, by providing the check valve 51, the working fluid can flow to the head-side chamber 45h and the rod-side chamber 45r to cool the cylinder 43. That is, by providing the check valve 51, both preparation for absorbing fluctuating pressure and cooling based on the circulation of the working fluid are achieved. Moreover, as mentioned above, the switching valve 55 also helps to form the bypass circuit 53. Thus, the absorption device 2 is multifunctional with a simple structure.

[0222] The absorption device 2 may also include an accumulator 65, an ACC flow path 67A, and an ACC valve 69. The ACC flow path 67A extends from the accumulator 65 to the head chamber 45h. In other words, the ACC flow path 67A may have one end located in the accumulator 65 and the other end located in the head chamber 45h. The ACC valve 69 may be located in the ACC flow path 67A and may be opened by the pressure of at least one of the accumulator 65 and the head chamber 45h, and may be closed by the introduction of a pilot pressure.

[0223] In this case, it becomes easy to reduce the pressure loss between the head chamber 45h and the accumulator 65. This effect is particularly enhanced when the ACC flow path 67A does not have other valves. Therefore, for example, pressure can be easily transmitted between the head chamber 45h and the accumulator 65, and fluctuating pressure can be easily absorbed by the accumulator 65.

[0224] The absorption device 2 may also include a supply unit (e.g., hydraulic device 63) for supplying hydraulic pressure to the head chamber 45h and a control device 5 for controlling the hydraulic device 63. The control device 5 can supply hydraulic pressure (see reference) to the head chamber 45h by the hydraulic device 63 during the period from before the molding material (molten metal 109) injected into the mold (mold 101) reaches the advance / retractor 41 (the specific time point is arbitrary as described above) until its arrival. Figure 5 ).

[0225] In this case, the degree of absorption of the fluctuating pressure by the absorption device 2 is determined according to the specified pressure. In another viewpoint, for example, in a method where fluctuating pressure is absorbed solely by the restoring force of the spring pressing the piston 47 against the rod-side chamber 45r (this method may also be included in this disclosure), the degree of absorption of the fluctuating pressure cannot be adjusted. However, in this embodiment, the degree of absorption can be adjusted. That is, in the absorption device 2, not only is the absorption of fluctuating pressure facilitated, but the control of the fluctuating pressure is also facilitated. Thus, for example, not only is the possibility of burr formation easily reduced, but also sufficient pressure is easily applied to the molten metal 109 when filling is complete, thereby easily reducing the possibility of porosity.

[0226] The control device 5 can change the specified pressure (in other words, the target pressure of the head chamber 45h (accumulator 65) before absorbing the fluctuating pressure) according to the temperature of the mold (mold 101).

[0227] In this case, for example as described above, the degree of absorption of the fluctuation pressure can be changed in accordance with the change in the magnitude of the fluctuation pressure caused by the change in temperature of the mold 101. That is, the precision of fluctuation pressure control is improved. As a result, the effect of reducing both burrs and porosity is improved.

[0228] After the molding material (molten metal 109) injected into the mold (mold 101) reaches the advancing and retracting member 41 and causes the advancing and retracting member 41 to retract, the control device 5 can supply the supply unit (e.g., hydraulic device 63) with a higher hydraulic pressure than the specified pressure (in other words, the pressure of the head side chamber 45h when absorbing fluctuating pressure) to the head side chamber 45h, thereby causing the advancing and retracting member 41 to advance and perform local pressure.

[0229] That is, the fluctuation pressure absorption device 2 can also be used as a local pressurization device. This simplifies, for example, the structure of the die-casting machine DC (or die-casting machine 1 or absorption device 2) with molds. Furthermore, local pressurization can begin from a state where the working fluid in the head chamber 45h is compressed while the advance / retractor 41 is retracting, thus allowing for rapid initiation of local pressurization. As a result, for example, product quality is improved.

[0230] In a different viewpoint, the hydraulic device 63 of the fluctuation pressure absorption device 2 in the embodiment is connected to a hydraulic cylinder 43. The cylinder 43 has a rod 49, a piston 47, and a cylinder component 45. The rod 49 is fixed to a retractable member 41 that can move forward into the mold (mold 101) and backward to the opposite side. The piston 47 is fixed to the rod 49. The cylinder component 45 houses the piston 47. The interior of the cylinder component 45 is divided by the piston 47 into a rod-side chamber 45r where the rod 49 is located and a head-side chamber 45h on the opposite side. The hydraulic device 63 has a bypass circuit 53. The bypass circuit 53 connects the rod-side chamber 45r and the head-side chamber 45h during the process where the retractable member 41 moves backward due to the pressure of the molten metal 109 inside the mold 101, causing the piston 47 to move from the rod-side chamber 45r side to the head-side chamber 45h side.

[0231] In this case, for example, similar to the function of flow path 61 including check valve 51, when fluctuating pressure is applied to advance / retract member 41 and piston 47 retracts, the working fluid in head side chamber 45h can be replenished to rod side chamber 45r using the pressure generated in head side chamber 45h. It should be noted that the bypass circuit (53) is not limited to being independent of flow path 61. In the case where the rod side chamber 45r and head side chamber 45h are connected during the movement of piston 47 from rod side chamber 45r to head side chamber 45h, flow path 61 can be understood as an example of the bypass circuit described above, unlike the description of the embodiment.

[0232] In another viewpoint, different from the above, the hydraulic cylinder (cylinder 43) of the embodiment has a cylinder component 45, a piston 47, a rod 49, and a one-way valve 51. The piston 47 is housed within the cylinder component 45, dividing the interior of the cylinder component 45 into a rod-side chamber 45r and a head-side chamber 45h. The rod 49 is fixed to the piston 47 and extends outward from the cylinder component 45 via the rod-side chamber 45r. The one-way valve 51 is included in the piston 47 and, during the movement of the piston 47 from one side of the rod-side chamber 45r to the side of the head-side chamber 45h, allows flow from the head-side chamber 45h to the rod-side chamber 45r and prohibits flow in the opposite direction. In other views, the piston 47 does not have a special mechanism that allows one-way flow of the one-way valve 51 to be effective only when it is at its forward and / or backward limits.

[0233] According to such a cylinder 43, for example in the absorption device 2 of the above embodiment, it is possible to realize that the piston 47 includes a one-way valve 51.

[0234] Of the various configurations described above, die-casting machine 1 or die-casting machine DC with mold is an example of a forming machine. Molten metal 109 is an example of a forming material. Mold 101 is an example of a mold. Cylinder 43 is an example of a hydraulic cylinder. Hydraulic device 63 is an example of a supply unit.

[0235] This invention is not limited to the above-described embodiments and can be implemented in various ways.

[0236] The molding machine is not limited to a die-casting machine. For example, it can be other metal molding machines, injection molding machines for molding resins, or molding machines for molding materials such as wood flour mixed with thermoplastic resins. Furthermore, the molding machine is not limited to horizontal molded transverse injection molding; for example, it can also be vertical molded longitudinal injection molding, vertical molded transverse injection molding, or horizontal molded longitudinal injection molding. The die-casting machine is not limited to a cold chamber machine; for example, it can also be a hot chamber machine.

[0237] Injection is not limited to low-speed and high-speed injection; for example, laminar flow filling can also be performed at low speed. The advance / retractor can also serve as an ejector pin for pushing the molded part, formed by the solidification of the molding material, out of the mold. The ripple pressure absorption device may not be used for localized pressurization.

[0238] As mentioned earlier, the bypass circuit 53 may not be required. In this case, the rod-side chamber 45r may, for example, prevent the discharge of working fluid from port 45b, or it may allow it (for example, port 45b may also be connected to the reservoir 59). Furthermore, the bypass circuit 53 may not be connected to the pump 57.

[0239] In the embodiment, the state of the hydraulic device 63 when the forward / reverse component 41 is advanced ( Figure 8 ) and the state of the hydraulic device 63 when the forward / reverse component 41 is in standby mode at the forward limit ( Figure 5 They are different. However, they can also be the same. For example, they can be used without utilizing... Figure 8 In the state, and Figure 5 The piston 47 is advanced under these conditions. Conversely, in a manner that does not utilize a bypass circuit, it is also possible to... Figure 8 In the state where pilot pressure is not introduced into ACC valve 69, wait for the molten metal to reach the advance / retreat component 41.

[0240] Alternatively, the accumulator 65 may not be provided. For example, the head chamber 45h may also be connected to the liquid storage section 59 via an overflow valve.

[0241] It should be noted that the concept of an absorption device that does not require a one-way valve (51) as a necessary condition can be extracted from this disclosure. For example, the concept of an absorption device having a bypass circuit 53 that connects the head side chamber 45h and the rod side chamber 45r can be extracted, or the concept of an absorption device that adjusts the degree of absorption of fluctuating pressure (pressure of the head side chamber 45h) according to the temperature of the mold can be extracted.

[0242] Explanation of reference numerals in the attached figures

[0243] DC: Die-casting machine with mold (forming machine)

[0244] 1: Die casting machine (forming machine)

[0245] 2: Fluctuation pressure absorption device

[0246] 5: Control device

[0247] 7: Mold Closing Device

[0248] 9: Injection device

[0249] 41: Forward and Reverse Components

[0250] 43: Cylinder

[0251] 45: Cylinder components

[0252] 45h: Cephalic ventricle

[0253] 45r: Rod-side chamber

[0254] 47: Piston

[0255] 49: Pole

[0256] 51: Check valve

[0257] 63: Hydraulic device

[0258] 101: Mold (mold).

Claims

1. A fluctuating pressure absorbing device, characterized by, Having: a hydraulic cylinder having a rod fixed to a reciprocating member capable of advancing into a mold and retreating from the opposite side thereof, a piston fixed to the rod, and a cylinder member accommodating the piston, the inside of the cylinder member being divided by the piston into a rod-side chamber where the rod is present and a head-side chamber on the opposite side thereof; a check valve allowing flow from the head-side chamber to the rod-side chamber and prohibiting flow in the opposite direction during movement of the piston from one side of the rod-side chamber to one side of the head-side chamber due to retreat of the reciprocating member caused by pressure of a molding material in the mold.

2. The fluctuation pressure absorbing device according to claim 1, wherein the check valve is included in the piston.

3. The fluctuation pressure absorbing device according to claim 1, further having a bypass circuit that, during retreat of the reciprocating member due to pressure of a molding material in the mold and movement of the piston from one side of the rod-side chamber to one side of the head-side chamber, communicates the rod-side chamber and the head-side chamber independently of a flow path including the check valve.

4. The fluctuation pressure absorbing device according to claim 3, further having a switching valve that switches connection relationships of the rod-side chamber, the head-side chamber, a hydraulic source, and a reservoir, the switching valve is switchable between a first state, a second state, and a third state, the first state connects the rod-side chamber, the head-side chamber, and the hydraulic source to each other, the second state connects the rod-side chamber and the hydraulic source to each other and connects the head-side chamber and the reservoir to each other, the third state connects the rod-side chamber and the reservoir to each other and connects the head-side chamber and the hydraulic source to each other, the bypass circuit is constituted by switching the switching valve to the first state.

5. The fluctuation pressure absorbing device according to claim 4, further having a control device that, after retreat of the reciprocating member due to pressure of a molding material in the mold and before arrival of a molding material in the mold at the reciprocating member in a next molding cycle, makes the switching valve the third state. further having: an accumulator; an ACC flow path from the accumulator to the head-side chamber; 6. The fluctuation pressure absorbing apparatus according to claim 1, wherein an ACC valve in the ACC flow path that is opened by pressure of at least one of the accumulator and the head-side chamber and is closed by introduction of a pilot pressure. further having: a supply portion that imparts hydraulic pressure to the head-side chamber; a control device that controls the supply portion, 7. The fluctuation pressure absorbing apparatus according to claim 1, wherein the control device causes the supply portion to impart hydraulic pressure of a prescribed pressure to the head-side chamber during a period from arrival of a molding material injected into the mold at the reciprocating member until arrival.

8. The fluctuation pressure absorbing device according to claim 7, wherein the control device changes the prescribed pressure in accordance with temperature of the mold.

9. The fluctuation pressure absorbing device according to claim 7, wherein ​ ​ ​ The control device applies a higher hydraulic pressure than the prescribed pressure to the head-side chamber after the molding material injected into the mold reaches the advance-and-retreat member and causes the advance-and-retreat member to retreat, thereby causing the advance-and-retreat member to advance and perform partial pressurization.

10. A hydraulic device of a fluctuation pressure absorbing device, the hydraulic device being connected to a hydraulic cylinder having a rod fixed to an advance-and-retreat member that can advance into a mold and retreat to the opposite side thereof, a piston fixed to the rod, and a cylinder member that houses the piston, an inside of the cylinder member being divided by the piston into a rod-side chamber where the rod is located and a head-side chamber on the opposite side thereof, characterized by having a bypass circuit that communicates the rod-side chamber and the head-side chamber during movement of the piston from one side of the rod-side chamber to one side of the head-side chamber due to retreat of the advance-and-retreat member caused by the pressure of a molding material in the mold.

11. A forming machine characterized by having the fluctuation pressure absorbing device according to claim 1; a clamping device that holds the mold; an injection device that injects a molding material into the mold.

12. A hydraulic cylinder characterized by, having a cylinder member; a piston housed in the cylinder member, the piston dividing an inside of the cylinder member into a rod-side chamber and a head-side chamber; a rod fixed to the piston, the rod extending out to the outside of the cylinder member via the rod-side chamber; a one-way valve included in the piston, the one-way valve permitting flow from the head-side chamber to the rod-side chamber and prohibiting flow in the opposite direction during movement of the piston from one side of the rod-side chamber to one side of the head-side chamber.

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