JP4552980B2 - Injection molding control device - Google Patents

Description

  The present invention relates to an injection molding control apparatus for injection molding of a molten material with a mold, and in particular, controls from a speed control process to a pressure control process in controlling an injection hydraulic cylinder during injection molding of a die casting machine or a resin molding machine. The present invention relates to an injection molding control device that can apply a predetermined pressure to the molten material.

  Aluminum is a light and good conductor for heat and electricity, has good corrosion resistance and high strength, and has excellent workability such as casting and forging. Used for parts and structural materials. For example, in an automobile or the like, an aluminum alloy part is incorporated for the purpose of weight reduction. In order to manufacture such a part, a die casting machine in which a molten aluminum alloy is injection-molded with a mold is used.

  In recent years, high quality products have been required for products molded with this die casting machine. The performance of the injection part of the die casting machine is characterized by the control of the metal pressure during injection molding. In order to obtain a high quality product, the speed and pressure of the injection cylinder that generates the metal pressure must be controlled in the order of milliseconds (ms).

  Therefore, in order to explain the control state, the configuration of the injection section of the die casting machine is shown in FIG. The injection part includes a movable mold 1 and a fixed mold 2 that form a mold cavity 3, and the fixed mold 2 stores a predetermined amount of molten metal M injected into the mold cavity 3. A metal sleeve 4 is provided. A molten metal M of aluminum alloy is poured from an injection port 5 opened in the metal sleeve 4. The plunger head 6 moves in the metal sleeve 4 at a speed V from the direction opposite to the mold 2 of the metal sleeve 4. As the plunger head 6 moves, the molten metal M is filled into the mold cavity 3 from the metal sleeve 4.

The plunger head 6 is provided at the tip of the plunger rod 7. When the piston rod 8 of a hydraulic cylinder (not shown) is driven, the plunger head 6 moves according to the speed V of the piston rod 8. Is controlled. When filling the mold cavity 3 with the molten metal M poured into the metal sleeve 4 and performing injection molding, the speed V is not always controlled. To obtain a high-quality product, the plunger head The movement of 6 is controlled at a low speed from position p ₀ to position p ₁ (low speed range) and at a high speed from position p ₁ to position p ₂ (high speed range).

The position p ₁ where the space in the metal sleeve 4 is filled with the molten metal M becomes the high speed region start point, and the molten metal M is filled into the mold cavity 3 at high speed. The completion point is the position p _2. Immediately before the position p _2, the molten metal M flow resistance becomes large, the speed decreases rapidly. Increasing control, because starting from the vicinity of the position p ₂ (increasing pressure area) also increased metal pressure P _M, the molten metal M, after the completion of the filling, while being compressed, since clotting proceeds, the plunger, Beyond position _{p 2,} advanced by a very low speed, and stops at the position _{p 3.} Here, the molten metal M is cooled in the mold cavity 3 to become a product.

This metal pressure P _M, will be described with reference to the configuration of the injection portion of the die casting machine shown in FIG. Metal pressure P _M, by the plunger head 6 moves the metal sleeve 4, which occurs at the contact surface of the molten metal M of the plunger head 6, the molten metal M is completed filled in a mold cavity 3 When, it takes the metal pressure P _M in increasing the overall pressure time of the molten metal M in the mold cavity 3.

Here, when the output of the hydraulic cylinder and F _P, metal pressure P _M at the position p of the plunger head 6,
P _M = F _P / ( _dt area)
It is represented by Incidentally, the pressure in the first pressure chamber and a second pressure chamber for driving the hydraulic cylinder piston respectively P _H, and P _R, D unit the piston and the piston rod 8 coupled to the piston and d portion , The output _FP is
F _P = [(D part area) × P _H ] − [(D part area−d part area) × P _R ]
It is.

  As described above, in order to injection mold the molten metal M stored in the metal sleeve 4, the speed control in the low speed range and the high speed range and the pressure increase control in the pressure increase range are performed for the movement of the plunger head 6. Need to be In order to realize the injection molding of the molten metal M by controlling the movement of the plunger head 6, the hydraulic cylinder control is switched to the pressure increase control after the speed control, and the hydraulic pressure is obtained so as to obtain a predetermined hydraulic pressure output. A control circuit was configured. Various conventional examples of typical hydraulic control circuits will be described below.

FIG. 9 shows a differential hydraulic control circuit. The hydraulic cylinder 11 that is hydraulically controlled has a first pressure chamber H ₁ and a second pressure chamber R ₁ across a moving piston 12, and the piston 12 has a diameter D and is connected to the plunger rod 7. The piston rod 13 is provided. The diameter of the piston rod 8 is d.

The flow rate of the oil accumulated in the hydraulic pressure source ACC ₁ by the piston accumulator is controlled by the speed control valve 16 and enters the first pressure chamber H ₁ of the hydraulic cylinder, and the piston 12 moves to the left. At the same time the second oil pressure chamber _{R 1} enters the first pressure chamber _{H 1} through the valve 14. The pressures in the first hydraulic chamber H ₁ and the second hydraulic chamber R ₁ are substantially the same, and therefore, the amount of oil from the hydraulic source ACC ₁ may be an amount corresponding to the rod diameter d of the piston 12. However, the output is also schematic, (corresponding to the rod diameter d area) × (H ₁ room hydraulic) next, small.

If leftward plunger head 6 to a predetermined position p _2, for switching the pressure increase control priority process from the velocity control priority process, switching command is issued from the control unit (not shown). As a result, the valves 14 and 15 are controlled to “open to close” and “close to open”, respectively, and the flow of oil changes. That is, the oil in the second pressure chamber R ₁ passes through the pressure increasing time control valve 17 from the valve 15 and is discharged to the tank, and the hydraulic pressure in the second pressure chamber R ₁ becomes zero. On the other hand, the oil from the hydraulic pressure source ACC ₁ continues to enter the first pressure chamber H _1, and the output of the piston rod 13 becomes (the area of the piston diameter D) × (the maximum hydraulic pressure in the H ₁ chamber) at the maximum. . This is the state of the pressure increase control priority process.

  As described above, the differential hydraulic control circuit is switched from the speed control priority process to the pressure increase control priority process by alternately controlling the valves 14 and 15 on and off.

FIG. 10 shows a hydraulic control circuit using the boost method. The hydraulic cylinder includes a first hydraulic cylinder 21 and a second hydraulic cylinder 21 ′. The first hydraulic cylinder 21 includes a first pressure chamber H ₂₁ and a second pressure chamber R ₂₁ , and the second hydraulic cylinder 21 ′ includes a first pressure chamber _{H 22} second pressure chamber _{R 22} is provided. The oil is transferred to the piston 22 ′ of the second hydraulic cylinder 21 ′ through the oil in the first pressure chamber H ₂₂ of the second hydraulic cylinder 21 ′ at the tip of the piston rod 23 of the first hydraulic cylinder 21. The hydraulic pressure output of this boost system hydraulic control circuit is obtained from the piston rod 23 ′, and the piston rod 23 ′ is connected to the plunger rod 7.

Oil accumulated in the oil pressure source ACC ₂ is flow controlled by a valve 26 for speed control through valve 24 enters the first pressure chamber H ₂₂ of the hydraulic cylinder 21 ', the piston 22 moves to the left. At the same time, oil in the second pressure chamber _{R 22,} the process exits the tank. The oil amount at this time corresponds to the piston diameter d ′ corresponding to the differential piston rod diameter d. The output is the same in the case of the differential system. The valves 24 and 25 are switched by the control process switching command, and the oil flow passes from the hydraulic source ACC ₂ through the valve 25, through the pressure increase time control valve 27, and into the first pressure chamber H of the hydraulic cylinder 21. ₂₁ and outputs the same hydraulic pressure as in the differential system described above. At this time, oil in the second pressure chamber _{R 21,} the process exits the tank.

  In this hydraulic control circuit using the boost system, the valve 24 and the valve 25 are alternately turned ON and OFF, thereby switching from the speed control priority process to the pressure increase control priority process.

Next, FIG. 11 shows a hydraulic control circuit using a two-stage hydraulic source system. In the hydraulic control circuit of the boost method described above, the diameter of the piston rod 23 'as d, in the output control step, using the diameter D _C of the boost side piston, and boosts the oil pressure of the first pressure chamber H _22, predetermined The hydraulic pressure was output. In the two-stage hydraulic power source system here, the hydraulic pressure in the first pressure chamber H ₃ is accumulated in the pressure source ACC ₃₂ at a necessary high pressure from the beginning, and in the speed control priority process, the hydraulic pressure on the hydraulic power source ACC ₃₁ side is accumulated. Is used. In the pressure increase control priority process, the hydraulic pressure of the hydraulic pressure source ACC ₃₂ is used.

  As a result, as in the case of the differential system or the boost system described above, the speed control priority process is switched to the pressure increase control priority process by switching the valves 34 and 35 on and off.

Comparing the advantages and disadvantages of the hydraulic control circuit according to the three methods described above, the advantages are that the differential method has a small oil consumption of the hydraulic source ACC, the mechanism is simple, and the pressure-increasing mechanism is static. in the method, the mass of the movable piston is small, stable and easy to change the value of the last metal pressure P _M, the 2-stage hydraulic power source system, it is easy to change the final metal pressure P _M values stabilize, piston diameter while has become intermediate 2 system described above, for the disadvantage, in the differential method is intended mass of the piston to be movable large, difficult change of final metal pressure P _M values, in the boost mode, the mechanism However, the pressure-increasing mechanism is dynamic, and in the two-stage hydraulic source system, the amount of oil consumed by the hydraulic source ACC is large, two hydraulic sources ACC are required, and maintenance is increased.

  Therefore, considering the advantages and disadvantages of each hydraulic control circuit described above, as a hydraulic control circuit that switches from the speed control priority process to the pressure increase control priority process, as shown in FIG. 12, the differential system shown in FIG. By combining the features of the hydraulic control circuit and the hydraulic control circuit based on the two-stage hydraulic source system shown in FIG. 11, a hydraulic control circuit using one system can be formed.

Summarizing the characteristics of the hydraulic control circuit according to the various methods described above, in the speed control process, the injection cylinder diameter d and the pressure of the hydraulic source ACC are all the same for the differential method, the boost method, and the two-stage hydraulic source method. In the pressure increase control process, the final output is (area of piston diameter D) × (hydraulic pressure) in the differential method and boost method, whereas (boost cylinder diameter) in the two-stage hydraulic source method. the D area of _C) × (the pressure of the hydraulic source).

Here, the hydraulic characteristics in the hydraulic control circuit will be described using a differential hydraulic control circuit as an example. The hydraulic characteristic graph is shown in FIG. In the figure, the horizontal axis indicates the time axis in milliseconds (ms) and is graduated in units of 10 ms. The time 0 indicates the timing when the filling of the molten metal M into the mold cavity 3 is completed and the pressure increase control is started (at the time of completion of high-speed filling and the pressure increase start reference point). It is. The left vertical axis indicates the velocity V of the plunger head. Furthermore, the right vertical axis, the first pressure chamber _{H 1} of the hydraulic _{P H,} the second pressure chamber _{R 1} of the hydraulic _{P R,} and, are expressed metal pressure _{P M,} respectively, a hydraulic _{P H} and _{P R,} in the metal pressure P _M, since the size of the values are different, are Chigae the degree of scale.

As illustrated in FIG. 8, at the time of injection molding of the molten metal M, and the metal pressure P _M is generated, in order to better product quality is obtained, the change with time of the metal pressure P _M at the time of the injection molding , in the graph of FIG. 13, it is desirable that the curve P _M represented by a thick solid line. That is, until time t ₃ , the speed control process is performed, and at time t ₃ , the ON / OFF states of the valves 14 and 15 are switched, and after proceeding to the pressure increase control process, the pressure is increased to a predetermined pressure value. Is.

To generate such a metal pressure P _M, the hydraulic control circuit according to a differential scheme shown in FIG. 9, first, the ON the valve 14, by controlling the valve 15 to OFF, the hydraulic pressure P _H and the hydraulic P _R The piston 12 is driven at a predetermined speed V in the left direction due to the difference. After time t ₂ , that is, as shown in FIG. 7, when the plunger head 6 approaches the position p ₂ , the molten metal M is almost filled in the mold cavity 3, so that the speed V is a natural deceleration. Begins.

At time t ₃ when the complete filling of the molten metal M is completed, the hydraulic pressure P _H and the hydraulic P _R becomes equilibrium, or more hydraulic this equilibrium, not high. Therefore, it means that does not increase the metal pressure P _M, at the timing of the time t _3, it controls so as to start the pressure increase control process. Therefore, the OFF valve 14, by controlling the valve 15 to ON, flows second oil hydraulic chambers _{R 1} is the tank is depressurized towards the hydraulic _{P R} 0, the hydraulic pressure acting on the piston 12, the hydraulic pressure P _H. At time t ₃ or later, if the hydraulic P _H is maintained, it is boosted metal pressure P _M is the hydraulic pressure P between the _R is 0-set pressure increase time t _4, so saturated at a predetermined pressure . The pressure increase of the metal pressure P _M, the plunger head 6, the process proceeds to the position p ₃ of increasing pressure area, stops here.

Note that the control system of valves 14 and 15, because there is some delay, as the ON · OFF controlled at the timing of time t _3, in terms of anticipation of the delay, at the stage of time t _1, A valve switching command is issued. At time t _3, it is controlled to switch smoothly to the pressure increase control process from the velocity control process.

Japanese Patent Laid-Open No. 2001-300715 JP 2001-26964 A Japanese Patent Laid-Open No. 03-158155 Japanese Patent Laid-Open No. 03-157583

However, in the hydraulic control circuit, there are cases where the speed control process cannot be smoothly switched to the pressure increase control process. The switching timing, for example, assuming that the delay 10ms from the time t ₃ of the switching plan, metal pressure P _M is a change such as a metal pressure P _M1 indicated by thick broken line in FIG. 13. This is because, in the hydraulic control circuit of the differential method, by reducing the pressure of the hydraulic P _R, so to obtain a metal pressure P _M, as in the hydraulic P _H1, is by starts to rise with a delay 10 ms. This change in the metal pressure P _M1 is a problem because it greatly affects the quality of products by injection molding.

Note that the metal pressure _PM1 shown in FIG. 13 shows a case where the switching of the valve 15 is delayed from the switching of the valve 14, but conversely, when the switching of the valve 14 is delayed from the switching of the valve 15. , to a second oil hydraulic chambers R ₁ will be pulled ahead, the first hydraulic chamber H ₁ oil pressure will be lowered temporarily, to metal pressure P _M is to be boosted , it will down, can not be obtained a high pressure as a whole (the graph of the metal pressure P _M at this time is not shown).

  In any of the hydraulic control circuits for controlling the hydraulic cylinders of the die casting machine, these can be switched from the speed control process to the pressure increase control process by ON / OFF control of the two valves. In the speed control step, the gas body in the mold cavity 3 is discharged as much as possible in the time that the solidified layer of the molten metal M filled in the sleeve 4 is maintained in an extremely thin state, and the molten metal M is discharged. In the filling step, the current practical value is V = 2 to 7 (m / s) in terms of the speed of the plunger head 6.

In the pressure increase control process, it is necessary to apply a high pressure to the molten metal M while the solidified layer of the molten metal M filled in the mold cavity 3 is in an extremely thin state, and the current practical value is the metal pressure P _M = 40 to 90 (MPa), pressure increasing time is about 0.01 to 0.1 second. The optimum value is selected and set within this range.

The practical value of the switching time from the speed control step to the pressure increase control step is 0.02 to 0.03 seconds, and it is important that there is no variation. For example, when the casting conditions mass-produced with the same mold are metal pressure P _M = 80 (MPa) and pressurization time = 0.03 (seconds), the variation in switching time is 0.02 seconds. Then, the pressure increasing time is 0.03 to 0.05 seconds, and the yield rate is significantly reduced. Therefore, the switching time from the speed control process to the pressure increase control process is required to be 0.01 to 0.02 seconds.

  Therefore, in order to control this, a resolution of 0.001 to 0.002 seconds is required. In particular, the synchronism between the valve 14 and the valve 15 is important. However, at present, the valve 14 and the valve 15 are independently controlled as independent valves. Therefore, the injection characteristics (time, speed, pressure) of these valves vary between the two valves. This characteristic difference results in an increase in switching time, which affects product quality and is a problem.

Each of the two valves in the hydraulic control circuit shown in FIGS. 9 to 11 is an independent valve and is composed of an electric actuator and a hydraulically operated valve. These variations are at the next level at present. .
Electric actuator system 0 to 0.009 seconds Hydraulic actuator system 0 to 0.015 seconds When these are combined, it becomes 0 to 0.024 seconds, so this switching time needs to be about 0 to 0.005 seconds. .

  Therefore, the present invention realizes the hydraulic control function using two valves in the hydraulic control of the hydraulic cylinder that drives the injection molding machine with one switching valve, and from the speed control process in the molten metal injection molding to the pressure increase control process. An object of the present invention is to provide an injection molding control device that can shorten the switching time and smoothly perform switching control between processes.

  In order to solve the above-described problems, in the present invention, in an injection molding control device that performs switching control from a speed control process to a pressure increase control process when molten metal is injection molded into a mold, the first port, the second port, and the second port A valve body having three ports, and a hollow movable sleeve having a first passage and a second passage which are slidable in the axial direction in contact with the inner surface of the main body within the valve body and are separated by a predetermined distance in the axial direction And a pilot pressure portion that slides the movable sleeve in the axial direction in the valve body, the first port communicates with the hollow portion, and the movable sleeve passes through the valve body. When the first pressure passage is aligned with the second port by sliding the pilot pressure portion, the first oil passage passing through the first port and the second port or the second passage is Matched to 3rd port Switching the hydraulic cylinder that switches to the second oil flow path passing through the first port and the third port and applies a predetermined pressure to the molten metal from the speed control step to the pressure increase control step; did.

  Further, the pilot pressure part divides the pressure chamber into a first pressure chamber and a second pressure chamber on a pressure chamber formed by an inner surface of the valve body and an outer surface of the movable sleeve, and an outer surface of the movable sleeve. A piston, and a first flow path and a second flow path communicating with each of the first pressure chamber and the second pressure chamber are disposed.

  When the oil flow is supplied from the first flow path to the first pressure chamber, the movable sleeve slides in one axial direction, the first passage is aligned with the second port, and the first When an oil flow is supplied from two flow paths to the second pressure chamber, the movable sleeve slides in the other axial direction, and the second passage is aligned with the third port.

  In the pilot pressure portion, an area related to the second pressure chamber of the piston is made smaller than an area related to the first pressure chamber, and further, a sliding outer surface of the movable sleeve contributing to formation of the second pressure chamber Was brought close to the inner surface of the valve body.

  The valve body has an acceleration pressure portion that applies acceleration pressure when the movable sleeve, which has been stopped at the axial end, starts sliding at the end of the body.

  The acceleration pressure unit includes a piston that supports a plate body that abuts on the end of the movable sleeve and is driven in the axial direction. The piston is oil supplied through a third flow path that communicates with the second flow path. By the flow, it is limitedly driven in the axial direction by a predetermined distance.

  Further, a pilot control valve for supplying a constant pressure oil flow to the pilot pressure portion through the first flow path or the second flow path is provided.

  The pilot control valve further includes first to third connection port portions. When the first connection port portion is selected, the oil flow is supplied to the second flow path, and the second connection port portion Is selected, the oil flow is supplied to the first flow path and the second flow path. When the third connection port portion is selected, the oil flow is supplied to the first flow path. In other words, the first to third connection port portions are selectively driven by the electromagnetic drive portion based on the switching command.

  As described above, according to the injection molding control apparatus of the present invention, in the conventional injection molding hydraulic control circuit, in order to switch from the speed control process to the pressure increase control process, two valves that are independently controlled must be used. Therefore, there is variation in the control of these valves, and the switching cannot be performed at an appropriate timing, but the switching functions of these two valves can be combined into one switching control device. As a result, the switching control from the speed control process to the pressure increase control process is smoothly performed, and the switching timing is not shifted.

  Further, in the pilot pressure chamber that drives the movable sleeve of the switching control device, the areas of the first pressure chamber and the second pressure chamber of the pressure chamber are made different, or acceleration is added only at the start of movement of the movable sleeve. Since the acceleration pressure section is provided, the time required for switching from the speed control process to the pressure increase control process can be greatly shortened.

  Next, an embodiment of the present invention that switches from a speed control process to a pressure increase control process when molten metal is injection molded will be described with reference to FIGS.

  In conventional hydraulic control circuits for injection molding, two valves that are independently controlled are used to switch from the speed control process to the pressure increase control process. Therefore, there is variation in the control of these valves, and the switching is performed. I couldn't do it at the right time. Therefore, the valves used in the hydraulic control circuit of the present embodiment are configured to combine the switching functions of these two valves into one switching valve. In this switching valve, the switching is performed smoothly, and a device for reducing the time required for the switching as much as possible has been devised.

  FIG. 1 shows a specific configuration relating to a switching valve for switching control from a speed control step to a pressure increase control step in a hydraulic control circuit to which the present embodiment is applied. In the figure, the switching valve 100 is shown in a cross section, and the pilot control valve 200 for operating the switching valve 100 is also symbolized.

  The switching valve 100 is based on a valve body 101. The valve body 101 has an axially long bottomed cylindrical shape with an appropriate thickness, and houses a movable sleeve 111 that slides on the inner peripheral surface thereof. ing. A P port 102 is opened at the end of the valve body 101, and an acceleration pressure forming unit 120 is provided at the other end. An A port 103 and a B port 104 are opened in the cylindrical wall portion of the valve body 101.

  The movable sleeve 111 accommodated in the valve body 101 is formed in a cylindrical shape in the axial direction and has a hollow inside. The cylindrical wall of the movable sleeve 111 is aligned with the A port 103 by sliding and moving in the axial direction, and is aligned with the passage 112 leading to the inside of the movable sleeve 111 and the passage leading to the inside with the B port 104. 113 is provided. When the movable sleeve 111 moves and the passage 112 overlaps the A port 103, an oil flow is formed between the P port 102 and the A port 103. When the passage 113 overlaps the B port 104, an oil flow is formed between the P port 102 and the B port 104. Either of these oil flows is formed by the movement of the movable sleeve 111.

Further, a pilot pressure chamber is formed in the cylindrical wall portion of the valve body 101 at a position away from the B port 104. The pilot pressure chamber includes a first pilot pressure chamber 105 and a second pilot pressure chamber 106, and each pressure chamber includes an inner peripheral recess provided in the cylindrical wall portion of the valve body 101, an outer peripheral surface of the movable sleeve 111, and the like. It is formed with. The diameter D _P of the inner peripheral recess formed in the cylindrical wall portion is larger than the diameter D _O of the movable sleeve 111. The pilot pressure chamber is partitioned into a first pilot pressure chamber 105 and a second pilot pressure chamber 106 by a pilot piston 114 attached to the outer peripheral surface of the movable sleeve 111.

The cylindrical wall portion of the valve body 101 is provided with a flow path a ₁ for injecting or extracting oil into the first pilot pressure chamber 105, and also injecting or extracting oil into the second pilot pressure chamber 106. flow path b ₁ for are provided. Therefore, by injecting oil to the first pilot pressure chamber 105 from the flow path a _1, if the flow path b ₁ passed through the oil of the second pilot pressure chamber 106, the movable sleeve 111, as viewed in FIG. 1, in the right direction moving, passage 112 becomes to match the a port 103, injected into the opposite, from the flow path _{a 1} disconnect the oil in the first pilot pressure chamber 105, the oil from the flow path _{b 1} to the second pilot pressure chamber 106 Then, the movable sleeve 111 moves leftward (in the direction of the arrow in the figure) as viewed in FIG. 1, and the passage 113 is aligned with the B port 103.

Even if the pilot pressure chamber is formed on the inner peripheral side of the cylindrical wall portion of the valve body 101 with the above-described configuration, for example, the flow of oil flowing from the P port 102 to the A port 103 is changed. To the oil flow from the B port 103 to the B port 103. If the opening positions of the passage 112 and the passage 113 are appropriately designed so that the positional relationship between the A port 103 and the B port 104 is appropriately adjusted, the oil amount in the flow passage a ₁ and the flow passage b ₁ can be adjusted to It is also possible to connect three passages of the port 102, the A port 103, and the B port 104.

In the configuration of the pilot pressure chamber described above, the moving speed of the movable sleeve 111 is the same in the left-right direction, assuming that the amount of oil flowing through the flow path a ₁ and the flow path b ₁ is constant. However, when the oil flow is switched from the A port 103 to the B port 104, it is necessary to speed up the operation. To address this case, the outer peripheral diameter D _S of the movable sleeve 111 to form a second pilot pressure chamber 106, I'll make larger than the outer peripheral diameter D _O of the other portions of the movable sleeve 111. That is, the relationship between the diameter of the pilot pressure _chamber, so that the _{D O <D S <D P} . In this way, if the amount of oil flowing through the flow path a ₁ and the flow path b ₁ is constant, the movement of the movable sleeve 111 is faster in the left direction than in the right direction.

  Note that when the switching valve 100 shown in FIG. 1 is installed with the P port 102 side down and the axial direction being vertical, the weight of the movable sleeve 111 itself affects the movement of the movable sleeve 111. However, if the relationship between the diameters of the pilot pressure chambers is as described above, the movable sleeve 111 can be easily held at the upper position, and when the movable sleeve 111 is moved downward, the moving speed thereof is set. There is an advantage of making it faster.

  On the other hand, when the switching valve 100 of FIG. 1 is installed with the axial direction horizontal, an acceleration pressure is formed on the side opposite to the P port 102 of the valve body 101 as a device for making the movable sleeve 111 move faster. Part 120 was provided. The acceleration pressure forming unit 120 presses the movable sleeve 111 itself only for a short time when the movable sleeve 111 starts to move, thereby overcoming the inertia when the movable sleeve 111 starts to move and increasing the speed of rising. You can expedite. As a result, the switching time of the switching valve 100 can be shortened.

Accelerating pressure forming unit 120, an acceleration pressure chamber has an acceleration piston 121 a slight distance S ₁ only movable diameter D _A, and, on the end of the accelerating piston 121 is movable sleeve 111 An abutting plate 122 is provided in contact with the end of the movable sleeve 11 when positioned on the rightmost side in the valve body 101. The size of the diameter _{D A} is are smaller than the diameter _{D O} of the movable sleeve 111.

A slight air gap is provided on the head side of the acceleration piston 121 in the acceleration pressure chamber, and a flow path b ₂ communicating with the flow path b ₁ is provided here. The distance to the side provided the gap S _1, disposing the channel b ₃ to and from the oil.

Oils such acceleration pressure forming unit 120 and are provided to the switching valve 100, when switching from the A port 103 side to the B port 104 side, the flow path b ₁ when moving the movable sleeve 111 to the left At this time, oil is also injected into the flow path b ₂ communicating with the flow path b _1, and as a result, the acceleration piston 121 is also pressurized. By this acceleration piston 121 is pressurized, the contact plate 122 only between the distance S _1, thereby pushing the movable sleeve 111. At this time, since oil is injected into the flow path b ₁ and oil is also injected into the second pilot pressure chamber 106, the movable sleeve 111 is about to move leftward by the pilot piston 114.

  Therefore, when the movable sleeve 111 starts to move from the rightmost position, the pressing force of the acceleration pressure forming unit 120 acts on the movable sleeve 111 in addition to the pressing force of the pilot pressure chamber. The rising speed of 111 can be increased. As a result, the installation of the acceleration pressure forming unit 120 shortens the switching time of the switching valve 100.

  The configuration of the switching valve 100 main body according to the present embodiment has been described above. Next, the pilot control valve 200 that controls switching of the switching valve 100 will be described. The pilot control valve 200 is shown in FIG. 1 by symbolizing its configuration.

The pilot control valve 200 is a valve for injecting or withdrawing oil into and from the flow path a ₁ and the flow path b ₁ provided in the switching valve 100. 205. The electromagnetic drive units 204 and 205 are driven and controlled by a drive power source 206 to switch between the three connection port units 201 to 203. This switching is performed by transmitting a command signal by microcomputer control to the drive command input terminal 207. The condition elements for transmitting the switching drive command include time, position, pressure, and speed, and these elements are constituted by a single element or a combination of plural elements.

The pilot control valve 200 has four ports, the P ₁ port is connected a pressure source having a constant hydraulic pressure, the other is a tank for storing the withdrawn oil is connected. A ₁ port, the flow path _{a 1,} and, _{B 1} port is connected to the flow path _{b 1.}

Here, when the pilot control valve 200 is driven and controlled by the connection port portion 201, oil of constant hydraulic pressure is injected into the flow path b ₁ through the B ₁ port, and the oil is extracted from the flow path a _1. Therefore, the movable sleeve 111 is accelerated and driven in the left direction. On the other hand, when the connection port unit 203 is driven and controlled, the oil having a constant hydraulic pressure is injected into the flow path a ₁ through the A ₁ port and the oil is extracted from the flow path b ₁ . Move to the right. At this time, accelerating the piston 121, by which the oil is withdrawn from the flow path b _1, back to its original position in preparation for the next acceleration.

By the way, for example, when the movable sleeve 111 is stopped at the right end position, the pilot control valve 200 is driven and controlled by the connection port portion 202. The connection port 202, a constant pressure of oil from P ₁ port to flow in both A _1-port and B ₁ port, for example, are connected to flow respectively by 1/2. Therefore, when stopping the movable sleeve 111, _{A 1} port to the flow path _{a 1, B 1} port is connected by small passage in the channel _{b 1.}

Therefore, when the movable sleeve 111 at the right end is moved leftward, the pilot control valve 200 is driven to switch from the connection port portion 202 to the connection port portion 201. Since 50% of the constant hydraulic pressure is applied to the flow path a ₁ and the flow path b ₁ from the P ₁ port, the time required for the hydraulic pressure applied to the flow path b ₁ to rise to 100% after switching. Can be shortened by 50%.

Therefore, the pilot control valve 200, when stopping the movable sleeve 111, since so as to apply a hydraulic pressure to each of A _1-port and B ₁ port, by devising the control of such a pilot control valve 200, the movable sleeve 111 Can be shortened from the stop state until the movement starts. As a result, the time required for switching from the A port 103 to the B port 104 in the switching valve 100 or vice versa can be shortened.

  Next, FIG. 2 shows a specific example of the first embodiment in which the switching valve 100 according to the present embodiment shown in FIG. 1 is applied to the differential hydraulic control circuit shown in FIG. . In the figure, the switching valve 100 incorporated in the hydraulic control circuit is shown as a switching valve 18 in a symbol system with a switching function. Since the oil flow in the speed control step and the pressure increase control step in the hydraulic control circuit related to the hydraulic cylinder is basically unchanged, each element other than the switching valve 18 in the hydraulic control circuit shown in FIG. The same thing is used, and the same sign is attached to the same thing.

Therefore, the operation of the differential hydraulic control circuit using the switching valve 18 according to the present embodiment will be described. The P port of the switching valve 18 is connected to the second hydraulic chamber R ₁ of the hydraulic cylinder 11, the A port is connected to the first hydraulic chamber H ₁ and the speed control valve 16, and the B port is pressure increase control. It is assumed that it is connected to the valve 17.

First, in the case of speed control the piston rod 13 of the hydraulic cylinder 11, in the conventional differential type hydraulic control circuit, the valve 14 in the ON state, and controls the valve 15 to the OFF state, from the hydraulic source ACC ₁ the oil was injected into the first hydraulic chamber H _1, they had to return the second oil hydraulic chamber R ₁ to the first hydraulic pressure chamber H _1. In the differential hydraulic control circuit of FIG. 2, in order to realize the function of the ON state of the valve 14 and the OFF state of the valve 15, the pilot control valve 200 is switched to the connection port portion 203 and the movable sleeve 111 is moved in the right direction. (Position shown in FIG. 1). When the movable sleeve 111 stops at a predetermined position, the connection port unit 203 is switched to the connection port unit 202. Thus, when the switching valve 18 is switching control, the oil of the second hydraulic chamber R ₁ from P port, returns to the first hydraulic chamber H ₁ through A port, enters the speed control process.

The oil accumulated in the hydraulic source ACC ₁ passes through the speed control valve 16 and enters the first hydraulic chamber H ₁ of the hydraulic cylinder 11 (in this case, the opening degree of the valve 16 is low). The piston rod 13, they move to the left, the second oil hydraulic chamber R ₁ enters the first hydraulic chamber H ₁ through the valve 14. When the piston rod 13 is moved to the position p ₁ corresponding place, command for high-speed injection is issued, the rate control valve 16 rapidly opens the opening (time, 0.01 seconds), the speed of the piston rod 13 Will be fast. The oil passage is the same as at low speed. When the piston rod 13 approaches at the position corresponding p _2, since flow resistance of the molten metal M is rapidly increased, speed is caused to fall rapidly, in proportion to the flow resistance metal pressure P _M, increases. This time is also about 0.01 seconds. The output corresponding to the hydraulic pressure control circuit is the maximum corresponding to the rod diameter d of the piston, and does not reach the pressure increase metal pressure value (P _M ). Thus, just before the position p _2, to actuate the switching valve 18, the output value corresponding to the piston diameter D is required.

Then, as the characteristics of the metal pressure P _M as shown in FIG. 13 is obtained, the speed control process continues until time t _3, needs to be switched to the pressure-increase control process from the velocity control process at the timing of the time t ₃ is there. In the conventional differential type control circuit, because it was subjected to switching control of the ON · OFF state independently a valve 14 and the valve 15, the influence of operation variation present in these valves, the desired metal pressure P _M I can't get it.

  Therefore, in the hydraulic control circuit shown in FIG. 2, switching control from the connection port portion 202 to the connection port portion 201 is performed in the pilot control valve 200 of the switching valve 18. Prior to this switching, the connection port portion 202 was connected, so when switched to the connection port portion 201, the movable sleeve 111 has a very short time due to the synergistic effect of applying acceleration pressure and shortening the rise time. The oil flow from the P port 102 is switched from the A port 103 direction to the B port 104 direction in a very short time.

  Here, when the distance between the passage 112 and the passage 113 provided in the movable sleeve 111 and the distance between the A port 103 and the B port 104 provided in the valve body 101 are appropriately adjusted and disposed, the above-described oil is involved. During the switching of the flow direction, there is a state in which the opening of the passage 113 faces the B port 104 while the passage 112 is aligned with the A port 103. In this state, before the oil flow is completely switched from the A port 103 direction to the B port 104 direction, as shown in the switching valve 18 of FIG. The intermediate state communicates with both. Accordingly, the oil flow direction is gradually switched even in the above-described extremely short time, and smooth switching can be realized without instantaneously interrupting the oil flow.

In this way, the timing by the drive control of the switching valve 18, it will be switched to the pressure increase control process from the velocity control process according to the hydraulic cylinder 11, switching in the switching valve 18 is suitable for the time t ₃ to carried out in, considering the delay of the control characteristics of the pilot control valve 200, a drive command signal to the pilot control valve 200, to send to the input terminal 207 at the timing of time t _1.

When the pilot control valve 200 is switching control to the connection port 201, to move the movable sleeve 111 to the final position of the left, at time _{t 1,} the passage 112 is entirely the A port 103 The passage 113 is perfectly aligned with the B port 104. When the switching at the switching valve 18 is in this state, the oil in the second hydraulic chamber R ₁ is drained, the hydraulic pressure of the hydraulic source ACC ₁ is applied to the first hydraulic chamber H ₁ , and the hydraulic cylinder 11 However, the process proceeds to the pressure increase control process.

As described above, according to the first embodiment, the switching valve 100 having the configuration shown in FIG. 1 is used as the switching valve 18 in the differential hydraulic control circuit shown in FIG. since to switch the pressure increase control process, the flow of oil for controlling, in a short period of time, moreover, smoothly switched, it is possible to obtain the characteristics of the desired metal pressure P _M as shown in FIG. 13 Thus, the switching timing can also be set accurately. Therefore, the quality of the product injection-molded by the die casting machine can be improved, and quality control becomes easy.

  So far, the case where the switching valve 100 according to the present embodiment shown in FIG. 1 is applied to a differential hydraulic control circuit has been described. However, other types of boost control or two-stage hydraulic source hydraulic control are used. The case where the switching valve 100 is applied to the circuit is the same as that of the differential hydraulic control circuit of FIG. FIG. 3 shows a case of a boost-type hydraulic control circuit as a second embodiment, and FIG. 4 shows a case of a two-stage hydraulic source-type hydraulic control circuit as a third embodiment.

  In the hydraulic control circuits according to the second and third embodiments, instead of the two valves that were conventionally controlled independently, they were replaced with the switching valve 100, which increased from the basic speed control process. Since the switching operation to the pressure control step is the same as the switching operation in the differential hydraulic control circuit shown in FIG. 2, the description thereof is omitted here.

  On the other hand, as a fourth embodiment, when the switching valve 100 of the present embodiment shown in FIG. 1 is applied to a combined hydraulic control circuit combining the differential method and the two-stage hydraulic power source method shown in FIG. Is shown in FIG. The hydraulic control circuit shown in FIG. 5 employs the basic configuration of the conventional hydraulic control circuit shown in FIG. 12, but the valve 44 and the valve 45 are replaced with the switching valve 51, and the valve 46 and the valve 47 are combined. Is characterized in that each is replaced by a switching valve 52. In FIG. 5, the switching valves 51 and 52 are indicated by simple valve symbols. However, the configuration of each switching valve itself is the same as that of the switching valve 100 shown in FIG. 1, and the switching valve shown in FIG. The same operation symbol as that of the valve 18 is used.

Respect switching valve 51, P port 102, the second hydraulic chamber _{R 4} of the hydraulic cylinder 41, A port 103 to the first hydraulic pressure chamber _{H 4} Then,, B port 103 is connected to the oil sump tank. Regarding the switching valve 52, the P port 102 is connected to the first hydraulic chamber H ₄ , the A port 103 is connected to the first hydraulic source ACC ₄₁ , and the B port 104 is connected to the second hydraulic source ACC _42. The

  The individual switching operations of the switching valves 51 and 52 are the same as those of the switching valve 100 shown in FIG. 1, and a pilot control valve 200 is connected for each switching control. The switching control is performed based on a drive command signal generated by the microcomputer.

To the hydraulic cylinder 41 in the state of the speed control step, and switching control of the pilot control valve 200 of the switching valve 52 to the state of the connection port 203, the oil from the first hydraulic pressure source ACC ₄₁ to the first hydraulic pressure chamber H ₄ The pilot control valve 200 of the switching valve 51 is controlled to switch to the state of the connection port 203 so that the oil in the second hydraulic chamber R ₄ flows into the first hydraulic chamber H ₄ . Each pilot control valve 200 is driven from the connection port unit 203 to the connection port unit 202.

Therefore, when the hydraulic cylinder 41 is controlled to be switched from the speed control process to the pressure increase control process, a drive command signal is sent from the microcomputer to each pilot control valve 200 at time t ₁ earlier than the actual switching timing time t _3. Send at the same time. Then, the pilot control valves 200 of the switching valves 51 and 52 are both driven and controlled from the connection port section 202 to the connection port section 201.

At this time, in the switching valves 51 and 52, the movable sleeve 111 is driven leftward in a short time, and after the P port 102, the A port 103, and the B port 104 are all in communication, The port is switched to a fully connected state. Therefore, oil in the second hydraulic chamber _{R 4} is a state that is pulled out to the tank, the oil pressure of the high pressure from the first hydraulic pressure source _{ACC 41} second hydraulic source _{ACC 42} is applied to the first hydraulic pressure chamber _{H 4.}

As described above, since the hydraulic cylinder 41 is switched from the speed control process to the pressure increase control process by a series of operation control of the switching valve, the flow of control oil is changed as in the first embodiment. , in a short time, moreover, smoothly switched, it is possible to obtain a higher characteristics desired metal pressure P _M of the pressure increase, for the switching timing can be set accurately. Therefore, it is possible to improve the quality of a product that is injection-molded by a die casting machine, and quality control becomes easy.

Therefore, the pressure characteristics in the hydraulic control circuit according to the fourth embodiment are shown in the graph of FIG. The display method of the graph shown in FIG. 6 is the same as that of the pressure characteristic graph shown in FIG. P _H is the hydraulic pressure of the first hydraulic chamber _{H 4, P R} is the hydraulic pressure of the second hydraulic chamber _{R 4,} and, _{P M} are respectively the metal pressure at the metal sleeve within 4. V represents the moving speed of the piston rod 43 of the hydraulic cylinder 41.

In FIG. 6, time t ₃ indicates the timing at which the speed control process is switched from the speed control process in the hydraulic control circuit to each of the pilot control valves 200 so that these processes are switched at this timing. switching drive command is issued at time t _1.

And pressure profile shown in FIG. 6, when comparing the pressure characteristics shown in FIG. 13, main difference is a hydraulic P _H in the pressure increasing control process. In the differential mode of the first embodiment, the first hydraulic chamber H ₁ oil pressure, but were those that rely on hydraulic power source ACC _1, in the case of composite mode according to the fourth embodiment of FIG. 6 , the hydraulic pressure of the first hydraulic chamber _{H 4} is a time _{t 3,} the first hydraulic pressure source _{ACC 41} has been switched to hydraulic by the second hydraulic pressure source _{ACC 42,} the hydraulic pressure _{P H} in the pressure increasing control step, the 1 The hydraulic pressure of the hydraulic pressure source ACC ₄₁ becomes higher.

Therefore, according to the hydraulic control circuit of a composite system according to the fourth embodiment, the metal pressure P _M after switching to pressure increase control process, the metal pressure P _M in the differential mode the hydraulic control circuit of the first embodiment It can be further increased, and the rise immediately after switching to pressure increase can be made steep. Therefore, it is possible to shorten the time of switching to pressure increase control process from the velocity control process, the pressure increasing time setting value from the time t ₃ to t _6.

Regarding the switching from the speed control process to the pressure increase control process at the time of injection molding, by using the switching valve according to the present embodiment of FIG. 1, the first to third embodiments shown in FIGS. By forming the hydraulic control circuit, the switching control is greatly improved, but the above-mentioned disadvantages are not eliminated. Therefore, by a hydraulic control circuit according to the fourth embodiment, it can increase the change width of the metal pressure P _M value, and the metal pressure P _M value is stable, can be the shortest switching time. Furthermore, it is possible to smooth the rise of the metal pressure P _M, if the metal pressure P _M value is constant, since the piston diameter D can be reduced, you are possible to provide a higher performance die casting machine.

  Therefore, according to the present invention, the switching timing from the speed control process to the pressure increase control process at the time of injection molding of molten metal can be changed, and the switching can be performed smoothly, and the desired metal can be changed. Since the pressure characteristics can be obtained, the quality of the injection molded product can be improved and stable quality control can be performed.

It is a block diagram explaining embodiment of the switching valve applied to the injection molding process switching control of this invention. It is a figure explaining the injection molding process switching control of 1st Embodiment which incorporated the switching valve of this embodiment in the hydraulic control circuit of the differential system. It is a figure explaining the injection molding process switching control of 2nd Embodiment which incorporated the switching valve of this embodiment in the hydraulic control circuit of the boost system. It is a figure explaining the injection molding process switching control of 3rd Embodiment which incorporated the switching valve of this embodiment in the hydraulic control circuit of a two-stage hydraulic power source system. It is a figure explaining the injection molding process switching control of 4th Embodiment which incorporated the switching valve of this embodiment in the composite type hydraulic control circuit. It is a figure explaining the pressure characteristic in the injection molding process switching control shown in FIG. It is a figure explaining the process of injection-molding a molten metal. It is a figure explaining the metal pressure when carrying out injection molding of the molten metal. It is a figure explaining the conventional differential-type hydraulic control circuit. It is a figure explaining the hydraulic control circuit of the conventional boost system. It is a figure explaining the hydraulic control circuit of the conventional two-stage hydraulic power source system. It is a figure explaining the conventional combined type hydraulic circuit of a differential and a two-stage hydraulic source system. It is a figure explaining the pressure characteristic when molten metal is injection-molded.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movable metal mold 2 Fixed mold 3 Mold cavity 4 Metal sleeve 5 Inlet 6 Plunger head 7 Plunger rod 8, 13, 23, 23 ', 33, 43 Piston rod 11, 21, 21', 31, 41 Hydraulic cylinder 12, 22, 22 ', 32, 42 Piston 14, 15, 24, 25, 34, 35, 44, 45, 46, 47 Valve 16, 26, 36, 48 Speed control valve 17, 27, 37, 49 Pressure increase Time control valve 18, 28, 38, 51, 52, 100 Switching valve 101 Valve body 102 P port 103 A port 104 B port 105 First pilot pressure chamber 106 Second pilot pressure chamber 111 Movable sleeve 112, 113 passage 114 pilot piston 115 Large diameter part 120 Acceleration pressure forming part 121 Acceleration piston 12 2 Contact plate 200 Pilot control valve 201, 202, 203 Connection port part 204, 205 Electromagnetic drive part 206 Drive power supply 207 Drive command input terminal a ₁ , b _{1 to} b ₃ flow path ACC _{1 to} ACC ₄₂ Hydraulic source H ₁ to H ₄ first hydraulic chamber R ₁ to R ₄ second hydraulic chamber

Claims (10)

An injection molding control device that controls switching from a speed control process to a pressure increase control process when molten metal is injection molded into a mold,
A valve body having a first port, a second port and a third port;
A hollow movable sleeve having a first passage and a second passage which are slidable in the axial direction in contact with the inner surface of the main body within the valve body and are separated by a predetermined distance in the axial direction;
A pilot pressure section that slides the movable sleeve in the axial direction in the valve body;
When the first port communicates with the hollow portion, the movable sleeve slides in the valve body by driving the pilot pressure portion, and the first passage is aligned with the second port, the first port A first oil passage that passes through one port and the second port, or a second oil passage that passes through the first port and the third port when the second passage is aligned with the third port. An injection molding control apparatus characterized in that a hydraulic cylinder that is switched and applies a predetermined pressure to the molten metal is switched from the speed control step to the pressure increase control step. The pilot pressure portion includes a pressure chamber formed by an inner surface of the valve body and an outer surface of the movable sleeve;
A piston that divides the pressure chamber into a first pressure chamber and a second pressure chamber on an outer surface of the movable sleeve;
The injection molding control device according to claim 1, wherein a first flow path and a second flow path communicating with each of the first pressure chamber and the second pressure chamber are provided. When an oil flow is supplied from the first flow path to the first pressure chamber, the movable sleeve slides in one axial direction, and the first passage is aligned with the second port,
When an oil flow is supplied from the second flow path to the second pressure chamber, the movable sleeve slides in the other axial direction, and the second passage is aligned with the third port. The injection molding control device according to claim 2.   The injection molding control device according to claim 2 or 3, wherein, in the pilot pressure portion, an area related to the second pressure chamber of the piston is made smaller than an area related to the first pressure chamber.   5. The injection molding control device according to claim 4, wherein, in the pilot pressure portion, a sliding outer surface of the movable sleeve contributing to formation of the second pressure chamber is brought closer to an inner surface of the valve body.   6. The valve body according to claim 2, further comprising an acceleration pressure portion for applying an acceleration pressure at the end of the body when the movable sleeve, which has been stopped at the axial end, starts to slide. The injection molding control device according to any one of the above. The acceleration pressure part has a piston that supports a plate that contacts the end of the movable sleeve and is driven in the axial direction;
7. The piston according to claim 2, wherein the piston is limitedly driven in the axial direction by a predetermined distance by an oil flow supplied through a third flow path communicating with the second flow path. The injection molding control apparatus according to one item.   The injection according to any one of claims 2 to 7, further comprising a pilot control valve that supplies an oil flow having a constant pressure to the pilot pressure section through the first flow path or the second flow path. Molding control device. The pilot control valve has first to third connection ports,
When the first connection port portion is selected, the oil flow is supplied to the second flow path,
When the second connection port portion is selected, the oil flow is supplied to the first flow path and the second flow path,
9. The injection molding control device according to claim 2, wherein when the third connection port portion is selected, the oil flow is supplied to the first flow path.   The injection molding control device according to claim 9, wherein the first to third connection port portions are selectively driven by an electromagnetic drive unit based on a switching command.

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