JP4048671B2 - Method for controlling mold clamping device and pressurizing mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold clamping device such as an injection molding machine or a die-cast molding machine, and is a so-called hybrid type that combines a hydraulic drive system used in a conventional large mold clamping apparatus and an electric drive system used in a small mold clamping apparatus. It is an object of the present invention to provide a mold clamping device control method and a pressurizing mechanism that greatly improve the energy saving performance of the clamping device.
[0002]
[Prior art]
Conventionally, hydraulic drive systems such as direct pressure type clamping devices and toggle type clamping devices have been the mainstream for mold clamping devices such as injection molding machines and die casting machines, but in recent years, in response to demands for energy saving and cleanliness. In addition, electric drive type mold clamping devices that perform mold opening / closing drive by converting the rotational movement of the servo motor into a linear movement using a ball screw nut have become popular, especially in small molding machines.
[0003]
[Problems to be solved by the invention]
However, although a small mold clamping device using the electric drive system can meet the demands for energy saving and cleanliness, it is possible to apply the servo motor and ball screw to a large mold clamping device by sizing it as it is. Since there is a limit to enlargement, there is a problem that enlargement of the mold clamping device is restricted. Therefore, a hybrid mold clamping device has been devised that uses an electric drive system for the mold opening / closing drive means and a hydraulic system for the mold clamping force generating means.
For example, in Japanese Patent Laid-Open No. 6-246806, a nut member is rotated by an AC servo motor, and a male screw member that is screwed to the nut member is moved to close the hydraulic operation plate, movable platen, and molding die. After fixing the hydraulic operating panel to the tie bar with a split clamp, the male screw member is further moved to pressurize the sealed liquid in the sealing bag provided in the closed chamber engraved in the hydraulic operating panel, and the piston Also disclosed is a hybrid mold clamping device that applies a mold clamping force to a molding die via a movable platen.
In the conventional hybrid mold clamping device as described above, the electric motor as a drive source must be constantly loaded while the mold clamping force is applied, so that sufficient energy saving performance cannot be exhibited. With the combined use of the hydraulic system, the structure of the mold clamping device becomes complicated and the failure frequency increases.
[0004]
[Means for Solving the Problems]
In order to solve the above-described problems, a method of controlling a mold clamping device according to the present invention includes a hydraulic pressure generating mechanism driven by a rotary motion of a servo motor and a hydraulic circuit that passes through a hydraulic circuit to a hydraulic chamber of a telescopic structure in the mold clamping device. The hydraulic oil is guided, and the mold clamping force is controlled by pressurizing the hydraulic oil sealed in the hydraulic chamber by the increase in the output of the servo motor. In this case, it is only necessary to reduce the load on the servo motor by operating a run-around circuit provided in the hydraulic circuit in the middle of pressure increase to the hydraulic pressure chamber, and a backflow prevention circuit provided in the hydraulic circuit After the pressure chamber pressure reaches a preset mold clamping pressure, the mold clamping force can be maintained by making the servo motor unloaded after operating.
[0005]
More specifically, hydraulic oil is guided from the hydraulic pressure generating mechanism driven by the rotational movement of the servo motor to the hydraulic chamber of the telescopic structure in the mold clamping device via the hydraulic circuit, and the output of the servo motor increases the output. Pressurize the hydraulic oil sealed in the hydraulic chamber to control the clamping force, and operate the run-around circuit in the hydraulic circuit during pressure increase to the hydraulic chamber to reduce the load on the servo motor Then, when the hydraulic chamber pressure reaches a preset mold clamping pressure, a backflow prevention circuit provided in the hydraulic circuit is activated, and then the servo motor is unloaded so that the mold clamping force is maintained. What is necessary is just to comprise.
[0006]
Blank
[0007]
The pressurizing mechanism of the mold clamping device according to the present invention includes a movable platen having a movable mold and arranged to be movable forward and backward, and a fixed having a fixed mold arranged to face the movable platen. A platen, a hydraulic chamber having a telescopic structure that is disposed between the fixed mold and a recess formed in the fixed platen and clamps the two molds, and an end of a cylinder rod of a hydraulic cylinder A screw shaft connected to the screw shaft, and a screw nut portion that is rotated by being screwed to the screw shaft and supported by the bearing, and a servo motor that transmits rotational force to the screw nut portion. And a control system for controlling the pressure of the hydraulic oil sealed in the hydraulic chamber by the output of the servo motor.
[0008]
Further, in such a pressurizing mechanism, it is only necessary to be able to arbitrarily set the mold clamping force by increasing or decreasing the pressure of the hydraulic oil sealed in the hydraulic chamber, and the hydraulic piping connecting the hydraulic chamber and the hydraulic pressure generating mechanism It is desirable to provide a backflow prevention circuit for maintaining the pressure of the hydraulic oil sealed in the hydraulic chamber in the middle of the operation. When the hydraulic oil pressure enclosed in the hydraulic chamber reaches a preset switching pressure, the load on the servo motor is switched to the run-around circuit that connects the hydraulic cylinder head side connection port and rod side connection port. Can be reduced. Furthermore, a plurality of hydraulic chambers can be provided.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 10 relate to an embodiment of the present invention, FIG. 1 is a longitudinal sectional view of an essential part of a hydraulic pressure generating mechanism, FIG. 2 is a plan view of the hydraulic pressure generating mechanism, and FIG. 3 is used for controlling a clamping force of a mold clamping device. FIG. 4 is an explanatory diagram of a control system for controlling the clamping force of the clamping device, FIG. 5 is a longitudinal sectional view of the clamping device in a typical embodiment, and FIGS. 6 to 8 are FIGS. Fig. 9 is a longitudinal sectional view of a mold clamping device in another different embodiment, Fig. 9 is a front view of the fixing platen of the mold clamping device as viewed from the mold mounting surface side, and Fig. 10 is another embodiment different from Fig. 9. It is the front view which looked at the stationary platen of the mold clamping device of this from the mold mounting surface side.
[0010]
The overall configuration of the present invention is broadly divided into a mold clamping device, a hydraulic pressure generating mechanism, a hydraulic circuit provided in the middle of a hydraulic pipe connecting the hydraulic pressure generating mechanism and the mold clamping device, and a control system. The configuration of a typical embodiment of the mold clamping device will be described below.
As shown in FIG. 5, rod holes are drilled at four corners of a fixed platen 52 which is erected with the base portion keyed on one end of a machine base 59 of the mold clamping device 50. One end of a tie rod 61 is inserted into each of the holes, and a tie rod nut 62 is screwed into a screw portion 61a at the tip of the tie rod 61. The tie rod nut 62 is fixedly provided with a tie rod nut rotating member 63 that is rotated in conjunction with the rotation of a rotation driving device (not shown), and a tie rod nut retainer 64 that is bolted to the fixed platen 52 is provided with the tie rod nut. The stepped portion of the nut 62 is covered with a slight gap.
On the other hand, the other ends of the four tie rods 61 are connected to each other at a predetermined interval by an end plate 58 and fixed by a non-rotating metal fitting 67 so as not to rotate.
[0011]
What is indicated by reference numeral 54 is a movable platen that is positioned between the fixed platen 52 and the end plate 58 and has a vertical plane opposed to the vertical plane of the fixed platen 52. The tie rod 61 passes through each of the rod holes drilled in the corners, and a guide shoe 66 that slides on the upper surface of the machine base 59 is fixed to the lower part of the movable platen 54.
[0012]
A plurality of ring grooves 61b are formed at equal intervals on the outer peripheral surface of the intermediate portion of the tie rod 61, and on the other hand, a half-shaped half disposed on the side opposite to the die mounting surface of the movable platen 54. On the inner peripheral surface of the nut 55, a plurality of inner peripheral protrusions that can be engaged with the ring groove 61b are provided at equal intervals.
The half nut 55 is configured to be opened and closed in a direction perpendicular to the mold opening / closing direction by driving a nut cylinder 68. When the movable platen 54 and the movable mold 84 are opened and closed, the half nut 55 is opened and held in a half state. At the same time, when the mold clamping force is applied, the movable platen 54 and the tie rod 61 are held in an engaged state by closing and engaging the inner peripheral protrusion of the half nut 55 with the ring groove 61b.
[0013]
One end of a ball screw member 72 is concentrically connected to the output shaft of a servo motor 71 for mold opening / closing drive mounted on the upper surface of the fixed platen 52, and faces the other end of the ball screw member 72. A through hole 54 a through which the ball screw member 72 can enter and exit is formed in the upper part of the vertical plane of the movable platen 54. A ball nut 73 that is screwed into the threaded portion 72a of the ball screw member 72 is bolted to the stepped portion of the through hole 54a.
In this way, when the servo motor 71 is operated to rotate the ball screw member 72, the movable platen 54 is integrated with the guide shoe 66 by the screw action of the ball nut 73 to advance and retract in the perspective direction with respect to the fixed platen 52. The movable mold 84 attached to the movable platen 54 opens and closes with respect to the fixed mold 82.
[0014]
Next, the structure of the mechanism part related to generation of mold clamping force of the mold clamping apparatus 50 will be described below.
A pressure receiving chamber 52a having a bottomed concave shape is formed in the center of the vertical surface of the fixed platen 52 on the side opposite to the tie rod nut 62, and a slide insert 53 is formed in the mold opening / closing direction on the opening side of the pressure receiving chamber 52a. It is slidably fitted to. Further, a bladder 51, which is a hollow hydraulic pressure chamber made of a stretchable material, is housed in a space surrounded by the bottom of the pressure receiving chamber 52a and the slide insert 53 without any gaps, and a hydraulic pressure generating mechanism 10 and a hydraulic circuit 30 described later. And the hydraulic oil pressurized and controlled by the control system 40 is comprised so that the inside of the said bladder 51 may be filled.
[0015]
The end surface of the slide insert 53 on the side opposite to the bladder is connected to a pressure plate 56, and the tie rod 61 is penetrated into the tie rod holes drilled in the four corners of the pressure plate 56 and the pressure is applied. A fixed die 82 is attached to the center portion of the die attachment surface which is the vertical surface on the side opposite to the slide insert of the plate 56. Further, a compression coil spring 57 is accommodated in a large diameter portion of a stepped through hole 56 a formed from the mold mounting surface side of the pressure plate 56, and the pressure plate is interposed via the compression coil spring 57. Bolts that connect 56 pass through the small diameter portion of the through hole 56 a and are screwed into the fixed platen 52.
[0016]
The operation of the mold clamping device 50 configured as described above will be described below.
The servo motor 71 for opening and closing the mold is operated from the mold open state to move the movable platen 54. When the movable mold 84 contacts the fixed mold 82, the operation of the servo motor 71 is stopped and the nut cylinder 68 is operated. Is operated to close the half nut 55, and the inner peripheral projection of the half nut 55 is engaged with the ring groove 61b, thereby holding the movable platen 54 and the tie rod 61 in an engaged state.
Next, when the bladder 51 is expanded by the pressure action of the hydraulic oil sealed in the bladder 51, the bladder 51 presses the back surface of the slide insert 53 and slightly moves the fixed mold 82 through the pressure plate 56. The mold is moved to the movable mold 84 side, and a clamping force is applied between the fixed mold 82 and the movable mold 84.
[0017]
On the other hand, when performing the mold opening operation, first, the pressure of the hydraulic oil enclosed in the bladder 51 is gradually decreased to reduce the mold clamping force. Then, due to the restoring force of the compression coil spring 57, the positional relationship among the fixed mold 82, the pressure plate 56, and the slide insert 53 is automatically returned to the positional relationship before the clamping force action. Subsequently, after operating the nut cylinder 68 to open the half nut 55, the servo motor 71 is operated to move the movable platen 54 to the mold opening limit position.
[0018]
As described above, in the mold clamping device control method and the pressurizing mechanism according to the present invention, the mold clamping force can be controlled only by controlling the pressure of the hydraulic oil sealed in the bladder 51. Accurate mold clamping force control is possible, and since it is a simple pressure mechanism that simply houses the bladder 51 in the pressure receiving chamber 52a engraved in the fixed platen 52 of the mold clamping device 50, there is no failure and durability. Is excellent. Combined with a ball screw electric drive type opening / closing mechanism, a clean hybrid clamping device excellent in energy saving and control accuracy suitable as a clamping device for an injection molding machine, a die casting machine or the like can be obtained.
[0019]
By the way, in a state where the movable mold 84 is in contact with the fixed mold 82, if the position of the ring groove 61b does not coincide with an appropriate position for meshing with the inner peripheral protrusion of the half nut 55, the movable platen 54 and the tie rod 61 Cannot be held in the engaged state. Therefore, when the mold is replaced, the tie rod 61 is moved in the axial direction according to the mold thickness (die height) prior to molding, and the position of the ring groove 61b is engaged with the inner peripheral protrusion of the half nut 55. It is necessary to adjust so-called die height to adjust the position.
[0020]
The operation at the time of die height adjustment in the mold clamping apparatus 50 shown in FIG. 5 will be described below. When a rotational drive device (not shown) is operated to rotate the four tie rod nut rotating members 63 in conjunction with each other, the four tie rods 61 are moved in the axial direction by screw action, and the position of the ring groove 61b of the tie rod 61 is also rotated. Move according to the amount of movement. Here, if the amount of rotation for moving the position of the ring groove 61b by the die height adjustment allowance (the amount of change in the die thickness) is selected, the movable die 84 is in contact with the fixed die 82 in any die. In this case, the position of the ring groove 61b of the tie rod 61 can always be matched with an appropriate position for meshing with the inner peripheral protrusion of the half nut 55.
In the mold clamping device 50 shown in FIG. 5, the length of the threaded portion 61 a that protrudes outside the fixed platen 52 becomes shorter as the mold thickness increases.
Note that the thick arrow in FIG. 5 is added to indicate the operation of the tie rod 61 at the time of die height adjustment, and in the axial direction by the length corresponding to the die height adjustment allowance without the tie rod 61 rotating. Indicates moving.
[0021]
Next, the configuration of the hydraulic pressure generating mechanism will be described below.
As shown in FIG. 2, the hydraulic pressure generating mechanism 10 includes a servo motor 22 as a drive source, a toothed belt 23 that transmits the rotational motion of the servo motor 22, a ball screw mechanism and a hydraulic cylinder 12 described below, and the like. The head side connection port 12c and the rod side connection port 12d of the hydraulic cylinder 12 are respectively connected to hydraulic piping of a hydraulic circuit 30 to be described later.
[0022]
As shown in the longitudinal sectional view of the main part of FIG. 1, the tip of the cylinder rod 12 a of the hydraulic cylinder 12 installed on the frame 11 is a ball screw shaft 14 that is a screw shaft that can move straight through a coupling 13. On the other hand, the small diameter portion 14b at the other end of the ball screw shaft 14 is supported by a bearing member 18 that can move linearly on the upper surface of the guide fitting 21. Further, the small-diameter portion 14b is prevented from being detached from the bearing member 18 by a retaining metal fitting 19 bolted to the end surface of the small-diameter portion 14b.
[0023]
A ball screw nut 15, which is a screw nut portion, is screwed onto the threaded portion of the ball screw shaft 14, and a rotating member to which rotational motion is transmitted to the ball screw nut 15 by the toothed belt 23. 17 is bolted. A ball screw nut 15 that rotates integrally with the rotating member 17 is supported by the frame 11 via a bearing member 16.
[0024]
The operation of the hydraulic pressure generating mechanism 10 configured as described above will be described below.
The rotational motion of the rotating member 17 transmitted through the toothed belt 23 by operating the servo motor 22 is converted into a linear motion of the ball screw shaft 14 by the screw action of the ball screw nut 15, and further to the ball screw shaft 14. The piston 12b fixed to the tip of the connected cylinder rod 12 is moved forward and backward. The hydraulic oil discharged from the hydraulic cylinder 12 by the movement of the piston 12b is guided into the bladder 51 via a hydraulic circuit 30 to be described later, and a clamping force is applied or released. In addition, since the ball screw shaft 14 is always supported at both points of the bearing member 16 and the bearing member 18, bending due to the weight of the ball screw shaft 14 is prevented.
[0025]
Since the servo motor 22 that is instantly activated is employed as the drive source of the hydraulic pressure generating mechanism 10, the servo motor 22 is stopped when the hydraulic pressure generating mechanism 10 becomes unloaded, and the hydraulic pressure generating mechanism 10 is brought into a loaded state. The servo motor 22 can be restarted immediately before. As a result, the electric energy (unload energy) consumed by the drive source when hydraulic energy is not consumed becomes zero, and a significant energy saving is achieved even in the total consumed energy. Further, since the hydraulic pressure generating mechanism 10 is not incorporated into the mold clamping device 50, hydraulic energy is transmitted from the hydraulic pressure generating mechanism 10 provided outside to the mold clamping device 50 via a hydraulic circuit described later. The structure of the device 50 is simplified and the durability is improved.
[0026]
Next, the configuration of a hydraulic circuit that supplies or discharges hydraulic oil to / from the bladder 51 to apply or release the mold clamping force will be described below.
As shown in FIG. 3, the hydraulic circuit 30 includes an electromagnetic valve 31 that switches communication / blocking to the tank side connection port 39, a pilot check valve 35 that prevents backflow of hydraulic oil from the bladder connection port 51 a, The solenoid valve 32 and the solenoid valve 33 for switching the open state / check state of the pilot check valve 35, the solenoid valve 34 for switching communication / blocking of the rod side oil chamber and the head side oil chamber of the hydraulic cylinder 12, and the maximum operating pressure From a relief valve 36 that functions as a safety valve of the hydraulic circuit 30 by setting a slightly higher pressure, a pressure detector 37 that detects the pressure of hydraulic oil supplied to the bladder connection port 51a at the pressure detector side connection port 38, and the like. It is configured.
[0027]
The operation and function of the hydraulic pressure generating mechanism 10 configured as described above will be described below.
When the mold clamping device is stopped, all solenoids of the solenoid valves in the hydraulic circuit 30 are demagnetized. From this state, after exciting the solenoid of the solenoid valve 31, the hydraulic pressure generating mechanism 10 is driven and the piston 12b is moved in the left direction in the figure, so that the head side connection port 12c of the hydraulic cylinder 12 enters the hydraulic circuit 30. The supplied hydraulic oil is guided to the pilot check valve 35. At this time, the solenoid of the solenoid valve 32 and the solenoid of the solenoid valve 33 are demagnetized, and the pilot check valve 35 is opened by the pressure of the hydraulic oil itself guided to the pilot check valve 35. The hydraulic fluid guided from the generating mechanism 10 passes through the pilot check valve 35, is guided to the bladder 51 through the bladder connection port 51a, and expands the bladder 51 while increasing the pressure inside the bladder 51.
[0028]
A pressure equivalent to the pressure inside the bladder is acting on the pressure detector side connection port 38, and a control described later is performed based on the detected pressure of the pressure detector 37 disposed in the pressure detector side connection port 38. Various switching commands are issued by the system.
First, when the detected pressure reaches a preset switching pressure, the solenoid of the solenoid valve 34 is excited to switch to the run-around state. Before switching to the run-around state, the piston 12b is pressed against the hydraulic pressure acting on the area corresponding to the cross-sectional area of the piston head of the hydraulic cylinder 12, whereas after switching to the run-around state, the rod Since the same pressure acts on the side oil chamber and the head side oil chamber, the pressure is pressed against the oil pressure acting on the area corresponding to the cross-sectional area of the cylinder rod of the hydraulic cylinder 12.
The higher the pressure inside the bladder 51, the greater the hydraulic pressure required for the hydraulic cylinder 12 and the load on the servo motor of the hydraulic pressure generating mechanism 10 increases. However, the servo is switched by switching to the run-around state during pressure increase. Since the motor load can be reduced, the servo motor 22, the ball screw 14 and the ball nut 15 can be reduced in size.
[0029]
After switching to the run-around circuit, the pressure inside the bladder 51 is further increased, and the pressure detected by the pressure detector 37 is set in advance as the mold clamping pressure (the pressure automatically converted and stored from the set mold clamping force). For a while after reaching the value, the output of the servo motor 22 of the hydraulic pressure generating mechanism 10 is controlled to be held at a constant pressure. On the other hand, when the detected pressure of the pressure detector 37 reaches a preset mold clamping pressure, the solenoid of the solenoid valve 33 is energized, and then the solenoid of the solenoid valve 32 is energized, the pilot check valve 35 is non-returned. The hydraulic circuit 30 is held in a state in which the pressure inside the bladder is confined, that is, in a backflow prevention state.
After that, even if the servo motor 22 is unloaded and the solenoid of the solenoid valve 31 and the solenoid of the solenoid valve 34 are demagnetized, the mold clamping force is maintained, so that significant energy saving is achieved in the mold clamping process. Further, when there is a leak from the pilot check valve 35 and the pressure gradually decreases, the pressure can be increased again when the pressure detected by the pressure detector 37 falls below a certain threshold value or at regular intervals.
[0030]
Before the mold clamping process is finished and the process proceeds to the mold opening process, the solenoid of the solenoid valve 32 is demagnetized, and then the solenoid of the solenoid valve 33 is demagnetized to open the pilot check valve 35, thereby opening the bladder 51. A part of the hydraulic oil is returned to a tank (not shown), and the hydraulic pressure generating mechanism 10 is returned to the state before starting pressurization (original position) in preparation for applying the clamping force of the next shot.
Solenoid excitation / demagnetization of the solenoid valve 31, solenoid valve 32, solenoid valve 33, and solenoid valve 34 described in the above description is a switching command (D1, D2, D3 shown in FIG. 3) issued from a driver group of a control system to be described later. , D4).
[0031]
A configuration of a control system that controls the hydraulic circuit 30 by transmitting a switching command will be described below.
As shown in FIG. 4, the control system 40 includes an arithmetic control device 42 that is a central part of the control system 40, a rotational position detector 49 of the servo motor 22 that transmits the rotational position signal S <b> 1 to the arithmetic control device 42, and arithmetic control. The pressure detector 37 that transmits the pressure signal S2 to the device 42, the servo driver circuit 47 that receives a command from the arithmetic control device 42 and transmits the rotation command to the servo motor 22, and the command that is received from the arithmetic control device 42. It comprises a driver group 48 that transmits switching commands D1, D2, D3, D4 to the solenoids of the solenoid valves 31, 32, 33, 34 of the hydraulic circuit 30, and the arithmetic control unit 42 sets the molding condition setting values. Measured data processing for receiving the molding condition setting storage unit 43 to store, the rotational position signal S1 from the rotational position detector 49 and the pressure signal S2 from the pressure detector 37 45, a feedback control unit 46 that receives a signal from the actual measurement data processing unit 45 and the molding condition setting storage unit 43 and transmits a command to the servo driver circuit 47, and a signal from the actual measurement data processing unit 45 and the molding condition setting storage unit 43 And a molding sequence control unit 44 that transmits a command to the driver group 48. The control system 40 is connected to a higher-level control system (not shown) (controls the entire machine), and can send and receive control signals related to the operating state and molding state of other devices.
[0032]
The control contents of the control system 40 will be described below.
The mold clamping pressure preset in the molding condition setting storage unit 43 (the pressure automatically converted and stored from the set mold clamping force) and the actual pressure obtained by processing the pressure signal S2 in the actual data processing unit 45 Is fed back by the feedback control unit 46, and pressure feedback control is performed by transmitting a rotation command from the feedback control unit 46 to the servo motor 22 via the servo driver circuit 47, and the mold clamping force during pressurization is changed every shot. It will be controlled constantly.
[0033]
The feedback control unit 46 compares the original position preset in the molding condition setting storage unit 43 and the actual position obtained by processing the rotational position signal S1 in the actual data processing unit 45, and the servo driver from the feedback control unit 46 Position feedback control is performed by transmitting a rotation command to the servo motor 22 via the circuit 47, and the position of the cylinder rod 12a before the start of pressurization is controlled to be constant every shot.
[0034]
Further, the feedback control unit 46 compares the cylinder speed set in the molding condition setting storage unit 43 in advance with the actual measurement speed obtained by processing the rotational position signal S1 in the actual measurement data processing unit 45. By transmitting a rotation command to the servo motor 22 via the servo driver circuit 47, speed feedback control is performed, and the step-up speed and the step-down speed are controlled to be constant for each shot.
[0035]
On the other hand, the molding sequence control unit 44 compares the switching pressure preset in the molding condition setting storage unit 43 with the actual measurement pressure obtained by processing the pressure signal S2 in the actual measurement data processing unit 45, and the two match. At the time, the run-around switching command D4 is transmitted to the solenoid of the solenoid valve 34 via the driver group 48, and the switching command D1 linked to the operation of the mold clamping device 50 according to the operation sequence preset in the molding sequence control unit 44. , D2, D3, D4 are transmitted to the solenoids of the solenoid valves 31, 32, 33, 34.
In the above embodiment, the set mold clamping force is held by pressure feedback control. However, the present invention is not limited to this. The output torque of the servo motor 22 is controlled to keep the mold clamping force constant. You can also.
[0036]
Thus, in the present invention constituted of the mold clamping device 50, the hydraulic pressure generating mechanism 10, the hydraulic circuit 30, and the control system 40, the rotational speed of the servo motor 22 is adjusted to arbitrarily set the increase / decrease change pattern of the mold clamping force. can do.
In particular, when removing the mold clamping force, the pressure generated by the hydraulic pressure generation mechanism 10 and the hydraulic circuit 30 is increased again to a predetermined pressure, and then the pilot check valve 35 is switched from the backflow prevention state to the open state. By gradually lowering the pressure while adjusting the rotation speed of the servo motor 22 so that the cylinder rod 12a of the hydraulic cylinder 12 is gradually retracted, vibrations and abnormal noises in various parts of the molding machine accompanying sudden pressure release Occurrence can be prevented.
[0037]
Next, the configurations and operations related to the die height adjustment are different from the typical embodiments of the mold clamping device described so far, and various embodiments will be described below mainly on the configurations and operations of different parts of the mold clamping device. Explained.
(Other embodiment-1)
As shown in FIG. 6, the range having the ring groove 61b of each tie rod 61 is wider than that of the representative embodiment (FIG. 5), and is engaged with the inner peripheral protrusion of the half nut 55 at each position within the die height adjustment range. It has become. With this alone, the die height can be adjusted to an integral multiple of the pitch of the ring groove 61b. However, since the die height cannot be changed less than one pitch, the die height adjusting servo motor 69 is operated to operate each tie rod nut rotating member 63 and each The tie rod nut 62 is rotated together and the tie rod 61 is moved in the axial direction with respect to the fixed platen 52 by the screw action of the tie rod nut 62 so as to be able to cope with a die height change of less than one pitch. As indicated by the thick arrow in FIG. 6 representing the operation content of the tie rod 61 at the time of adjusting the die height, the axial movement amount of the tie rod 61 is a minute amount within one pitch of the ring groove 61b.
[0038]
(Other embodiment-2)
As shown in FIG. 7, the range having the ring groove 61b of each tie rod 61 is wider than that of the representative embodiment (FIG. 5), and is engaged with the inner peripheral protrusion of the half nut 55 at each position within the die height adjustment range. Each tie rod nut 62 is fixed to the stationary platen 52 by a bolt (not shown), and a tie rod rotating member 65 is bolted to the end surface of each tie rod 61 on the threaded portion 61a side. With this alone, the die height can be adjusted to an integral multiple of the pitch of the ring groove 61b. However, since it cannot cope with a change in die height of less than one pitch, the servo motor 69 for adjusting the die height is actuated to operate each tie rod rotating member 65 and tie rod. The tie rod 61 is rotated in an interlocked manner, and the tie rod 61 is moved in the axial direction with respect to the fixed platen 52 by the screw action of the tie rod nut 62, so that a die height change of less than one pitch can be dealt with. Since each tie rod 61 is configured to rotate, the end plate 58 and the rotation stopper 67 in FIGS. 5 and 6 are unnecessary. The tie rod 61 moves in the axial direction as it rotates, as indicated by the thick arrow in FIG. 7 representing the operation of the tie rod 61 during die height adjustment.
[0039]
(Other embodiment-3)
5, 6, and 7, the screw portion 61 a is provided on the fixed platen 52 side of the tie rod 61, and the ring groove 61 b is provided in a portion where the half nut 55 is attached and detached. In the mold clamping device shown in FIG. 8, a ring groove 61c is provided on the fixed platen 52 side of the tie rod 61, and a threaded portion 61d is provided at a portion engaging with the half nut 75. Accordingly, the tie rod nut 74 engaged with the ring groove 61c of the tie rod 61 has a two-divided structure in which a ring-shaped inner peripheral protrusion is engraved, and is fixed to the fixed platen 52 by a bolt (not shown). . On the other hand, on the inner peripheral surface of the half nut 75 having a two-part configuration that is detachably attached to the screw portion 61d of the tie rod 61, a female screw that is screwed into the screw portion 61d is engraved. The range of each tie rod 61 having the threaded portion 61d is wide, and is engaged with the inner peripheral female screw of the half nut 75 at each position within the die height adjustment range. With this alone, the die height can be adjusted to an integral multiple of the pitch of the threaded portion 61d. However, since it cannot cope with a change in die height of less than one pitch, the die height adjusting servo motor 69 is actuated and the ring groove 61c side of each tie rod 61 is operated. By rotating the tie rod rotating member 65 fixed to the end face in an interlocking manner and moving the screw thread position of the threaded portion 61d at the position where the tie rod rotating member 65 is screwed with the half nut 75 in the axial direction, it is possible to cope with a die height change of less than one pitch. I am doing so. As shown by the thick line arrow in FIG. 8 showing the operation content of the tie rod 61 at the time of adjusting the die height, the tie rod 61 only rotates but does not move in the axial direction.
[0040]
In the mold clamping apparatus shown in FIGS. 5 to 8 described so far, the pressure receiving chamber 52a for accommodating the bladder 51 and the slide insert 53 is provided in the central portion of the fixed platen 52. In the case of a mold clamping device of an injection molding machine in which the nozzle touch hole 76 is formed, the pressure receiving chamber 52 a cannot be provided in the center portion of the fixed platen 52. Such a case can be dealt with by appropriately changing the shape and the number of the pressure receiving chambers 52a. A typical example will be described below.
[0041]
(Other embodiment-4)
As shown in FIG. 9, in the front view of the fixed platen 52 as seen from the mold mounting surface side, a ring-shaped pressure receiving chamber 78 is formed outside the nozzle touch hole 76 at the center of the fixed platen 52 to insert the bladder and the slide. The shape of the child can be a ring shape. Other configurations and operations are the same as those of the mold clamping device described so far.
(Other embodiment-5)
Since the size of the fixed platen 52 increases as the required mold clamping force increases, the mold clamping force required for the fixed platen 52 is increased as the size of the mold clamping device increases, for example, as shown in FIG. As many pressure receiving chambers 52a as necessary to obtain are engraved, and a plurality of bladders 51 and slide inserts 53 can generate mold clamping force.
[0042]
At that time, since the number of hydraulic pressure generating mechanisms 10 for supplying hydraulic oil to a plurality of bladders 51 can be arbitrarily selected, mold clamping is performed depending on the size limit of the servo motor 22, the ball screw 14 and the ball nut 15 of the hydraulic pressure generating mechanism 10. The enlargement of the device 50 is not limited. Accordingly, the mold clamping device 50 of the present invention is optimal for increasing the size of the hybrid mold clamping device because there is no factor limiting the increase in size in the design of the pressurizing mechanism and the design of the hydraulic pressure generating mechanism 10. When the servo motor 22, the ball screw 14 and the ball nut 15 of the hydraulic pressure generating mechanism 10 are within the limit of enlargement, by supplying hydraulic oil from one hydraulic pressure generating mechanism 10 to a plurality of bladders 51, It is desirable to simplify the hydraulic pressure generating mechanism 10, the hydraulic circuit 30, and the control system 40.
[0043]
5 to 10 shown as examples of the mold clamping device 50 so far, the pressure receiving chamber 52a is engraved in the fixed platen 52 to accommodate the bladder 51. However, the present invention is not limited to this. Instead, the pressure receiving chamber 52a may be formed in the movable platen 54 so that the bladder 51 is accommodated. However, in the movable platen 54 in which the ejector rod hole is drilled, the position where the pressure receiving chamber 52a is cut and the size of the bladder 51 are limited.
[0044]
【The invention's effect】
As described above, the present invention exhibits the following excellent effects.
(1) Since the hydraulic oil pressure can be gradually reduced by adjusting the rotation speed of the electric motor so that the cylinder rod of the hydraulic cylinder is gradually retracted, each part of the molding machine accompanying sudden pressure release Generation of vibrations and abnormal sounds can be prevented.
(2) When the hydraulic energy is not consumed, the electric energy consumed by the drive source becomes zero, and further, the hydraulic pressure generating mechanism is not incorporated into the mold clamping device, but is provided from the external hydraulic pressure generating mechanism via the hydraulic circuit. Since the hydraulic energy is transmitted to the mold clamping device, the structure of the mold clamping device is simplified. Combined with the ball screw drive type opening / closing drive mechanism, the mold clamping device has excellent energy saving and control accuracy, and excellent durability. can get.
(3) The mold clamping force can be arbitrarily set by increasing or decreasing the oil pressure enclosed in the bladder.
(4) By switching the pilot check valve to the non-return state and keeping the hydraulic oil inside the bladder confined, the mold clamping force is maintained even when the electric motor is unloaded. Energy saving is achieved, and a significant energy saving is achieved even in the total energy consumption.
(5) When the mold clamping pressure increases and reaches a preset switching pressure, the electric motor and ball of the hydraulic pressure generating mechanism are reduced by switching to the run-around circuit and reducing the electric motor load of the hydraulic pressure generating mechanism. Miniaturization of the screw is achieved.
(6) A plurality of pressure receiving chambers are engraved in the fixed platen, and hydraulic oil is supplied to a plurality of bladders accommodated therein to generate a mold clamping force, and the hydraulic oil is supplied inside the plurality of bladders. Since the number of hydraulic pressure generating mechanisms to be selected can be arbitrarily selected, the size of the hybrid mold clamping device can be increased.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a main part of a hydraulic pressure generating means according to an embodiment of the present invention.
FIG. 2 is a plan view of hydraulic pressure generating means according to an embodiment of the present invention.
FIG. 3 is a hydraulic circuit for controlling mold clamping force of the mold clamping apparatus according to the embodiment of the present invention.
FIG. 4 is an explanatory diagram of a control system for controlling the mold clamping force of the mold clamping device according to the embodiment of the present invention.
FIG. 5 is a longitudinal sectional view of a mold clamping device according to an embodiment of the present invention.
6 is a longitudinal sectional view of a mold clamping device according to another embodiment different from FIG. 5. FIG.
7 is a longitudinal sectional view of a mold clamping device according to another embodiment different from FIGS. 5 and 6. FIG.
FIG. 8 is a longitudinal sectional view of a mold clamping device according to another embodiment different from FIGS. 5 to 7;
FIG. 9 is a front view of the fixed platen of the mold clamping device according to the embodiment of the present invention as viewed from the mold mounting surface side.
FIG. 10 is a front view of a fixed platen of a mold clamping device according to another embodiment different from FIG. 9 as viewed from the mold mounting surface side.
[Explanation of symbols]
10 Hydraulic generation mechanism
11 frames
12 Hydraulic cylinder
12a Cylinder rod
12b Piston
12c Head side connection port
12d Rod side connection port
13 Coupling
14 Ball screw shaft (screw shaft)
14a end
14b Small diameter part
15 Ball screw nut (screw nut part)
16 Bearing member
17 Rotating member
18 Bearing members
19 Retaining bracket
21 Guide bracket
22 Servo motor
23 Toothed belt
30 Hydraulic circuit
31, 32, 33, 34 Solenoid valve
35 Pilot check valve
36 relief valve
37 Pressure detector
38 Pressure detector connection port
39 Tank connection
40 Control system
42 Arithmetic control device
43 Molding condition storage unit
44 Molding sequence controller
45 Measurement data processing section
46 Feedback control unit
47 Servo driver
48 Driver group
49 Rotation position detector
50 Clamping device
51 Bladder (hydraulic chamber)
51a Bladder connection port
52 Fixed platen
52a Pressure receiving chamber
52b Tie rod hole
53 Slide nesting
54 Movable platen
54a Through hole
55 Half nut
56 Pressure plate
56a Spring chamber
57 Compression coil spring
58 End plate
59 machine base
61 Tie Rod
61a Screw part
61b Ring groove
61c Ring groove
61d Screw part
62 Tie rod nut
63 Tie rod nut rotating member
64 Tie rod nut holder
65 Tie rod rotating member
66 Guide
67 Detent bracket
68 Nut cylinder
69 Servo motor
71 Servo motor
72 Ball screw member
72a Screw part
73 Ball screw nut
74 Tie rod nut
75 half nut
76 Nozzle touch hole
78 Ring-shaped bladder
82 Fixed mold
84 Movable mold
S1 Rotation position signal
S2 Pressure signal
D1, D2, D3, D4 switching command

Claims (8)

The hydraulic fluid is guided from the hydraulic pressure generating mechanism driven by the rotational movement of the servo motor to the hydraulic chamber of the telescopic structure in the mold clamping device via the hydraulic circuit, and is enclosed in the hydraulic chamber by the increase in the output of the servo motor. The hydraulic oil is pressurized to control the mold clamping force, and the run-around circuit provided in the hydraulic circuit is operated in the middle of pressure increase to the hydraulic pressure chamber to reduce the load on the servo motor. Control method of mold clamping device. The hydraulic fluid is guided from the hydraulic pressure generating mechanism driven by the rotational movement of the servo motor to the hydraulic chamber of the telescopic structure in the mold clamping device via the hydraulic circuit, and is enclosed in the hydraulic chamber by the increase in the output of the servo motor. The hydraulic fluid is pressurized to control the clamping force, and the backflow prevention circuit provided in the hydraulic circuit is operated when the hydraulic chamber pressure reaches a preset clamping pressure, and then the servo motor is turned off. control method to that type clamping device, characterized in that in the load and to hold the mold clamping force. The hydraulic fluid is guided from the hydraulic pressure generating mechanism driven by the rotational movement of the servo motor to the hydraulic chamber of the telescopic structure in the mold clamping device via the hydraulic circuit, and is enclosed in the hydraulic chamber by the increase in the output of the servo motor. The hydraulic oil is pressurized to control the mold clamping force, and the run-around circuit provided in the hydraulic circuit is operated during the pressure increase to the hydraulic pressure chamber to reduce the load on the servo motor. A mold characterized in that when a pressure reaches a preset mold clamping pressure, a backflow prevention circuit provided in the hydraulic circuit is operated, and then the servo motor is unloaded to maintain a mold clamping force. Method of controlling the fastening device. A movable platen having a movable mold and disposed so as to be movable forward and backward, a fixed platen having a fixed mold disposed to face the movable platen, a recess engraved in the fixed platen, and the fixed A hydraulic chamber having a telescopic structure disposed between the molds to clamp the molds;
A screw shaft connected to an end of a cylinder rod of a hydraulic cylinder and capable of moving in a straight line; a screw nut portion that is screwed and rotated with the screw shaft and supported by a bearing; and a rotational force applied to the screw nut portion A hydraulic pressure generating mechanism composed of a servo motor that transmits
A pressurizing mechanism for a mold clamping device, comprising: a control system for controlling the pressure of hydraulic oil enclosed in the hydraulic chamber by the output of the servo motor. 5. The pressurizing mechanism for a mold clamping apparatus according to claim 4 , wherein the mold clamping force can be arbitrarily set by increasing or decreasing the pressure of the hydraulic oil sealed in the hydraulic pressure chamber. In the middle of the hydraulic pipes connecting the hydraulic chamber and the hydraulic generating mechanism, to claim 4 or claim 5, characterized in that a backflow prevention circuit for holding the pressure of the hydraulic oil enclosed in the liquid within the pressure chamber The pressurizing mechanism of the mold clamping apparatus described. When the hydraulic oil pressure enclosed in the hydraulic chamber reaches a preset switching pressure, the load on the servo motor is switched to the run-around circuit that connects the hydraulic cylinder head side connection port and rod side connection port. The pressurizing mechanism of the mold clamping apparatus according to any one of claims 4 , 5 and 6 , wherein the pressure is reduced. 8. A pressurizing mechanism for a mold clamping apparatus according to claim 7 , wherein a plurality of hydraulic chambers are provided.

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