JP2001179790A - Mold clamping apparatus of mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a control system for mold clamping operation and mold opening and closing operation while achieving the speedup of operation and to miniaturize the whole of a mold clamping apparatus, in the mold clamping apparatus of a mold for reciprocally moving the movable mold 33 attached to a movable platen 34 between a mold opening position and a mold clamping position, by reciprocally driving the movable platen 34 and pressing the movable mold 33 to a fixed mold 32 at the mold clamping position by large mold clamping force. SOLUTION: A movable platen 34 is reciprocally driven in a mold clamping direction by a crank mechanism 50 and the crank mechanism 50 is constituted so that the movable platen 34 arrives at a mold clamping position when a crank pin 61 is moved to the vicinity of a dead point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device for clamping a mold attached to a molding machine such as an injection molding machine or a press molding machine.

[0002]

2. Description of the Related Art A molding die attached to an injection molding machine or a press molding machine requires a large force at the time of mold clamping.
Although a large force is not required at the time of the mold opening / closing operation other than at the time of mold clamping, it is necessary to perform the opening / closing operation at high speed in order to shorten the cycle time of the molding operation. As a mold clamping device for a molding die capable of securing a large mold clamping force and a high speed mold opening / closing operation, for example, there is a device shown in FIG.

A movable plate (15) having a movable mold (14) mounted thereon is disposed above a fixed mold (12) mounted and fixed on a base (11). (15) is a high-speed cylinder (17) (17)
And the lower end of the ram (17a) (17a) (18a) of the mold clamping cylinder (18). In addition, the high-speed cylinder (17) (17), the mold clamping cylinder (18), the main hydraulic device (21), and the auxiliary hydraulic device (2
2) is connected by hydraulic piping (24) (24). In this example, a molding die (A) composed of a fixed die (12) and a movable die (14)
To close the high-speed cylinder (1
7) Supply the hydraulic oil to (17) and advance the rams (17a) and (17a) at high speed, thereby lowering the movable mold (14) to the mold clamping position at high speed.

Next, a plasticizing resin is injected into the molding die (A) from the injection machine (30), and the main hydraulic device (21) and the auxiliary hydraulic device (22) are supplied to the mold clamping cylinder (18). Hydraulic oil is supplied, whereby the molding die (A) is clamped with a large clamping force. However, in the above-mentioned conventional one, a molding die
Not only are high-speed cylinders (17) and (17) for opening and closing (A) at high speed and mold-clamping cylinders (18) for securing large clamping force necessary, Since the hydraulic devices (21) and (22) incorporating the control valve and the hydraulic pump described above, as well as hydraulic piping and the like are required, there is a problem that the entire device becomes large. In addition, high-speed cylinders (17) and (17)
Since it is necessary to control a large number of control valves for the hydraulic circuit provided for expanding and contracting 8) in consideration of the operation timing, there is also a problem that the control system becomes complicated.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and discloses a method of moving a movable die attached to the movable plate by reciprocating the movable plate between a mold opening position and a mold clamping position. In the mold clamping position, the movable mold is pressed against the fixed mold side with a large mold clamping force at the mold clamping position. It is an object of the present invention to simplify a control system for operation and to reduce the size of the entire apparatus.

[0006]

Means for Solving the Problems [1] The technical means of the present invention for solving the above-mentioned problems is as follows: "The movable plate is configured to be reciprocated in a mold clamping direction by a crank mechanism; Is configured such that the movable mold reaches the mold clamping position when the crank pin moves to the vicinity of the dead center. "

According to the above technical means, when the movable mold at the mold open position is moved in the mold clamping direction, the crank constituting the crank mechanism may be rotated. Then, the rotational force is transmitted to the movable plate via the connecting rod constituting the crank mechanism, and moves in the mold clamping direction. At the initial stage when the movable platen starts moving in the mold clamping direction, the movable pin connected to the connecting rod moves at high speed in the mold clamping direction because the crankpin has not moved to the vicinity of the dead center. Eventually, when the crank pin moves to the vicinity of the dead center and the movable mold enters the mold clamping state, a straight line connecting the rotation center of the crank and the crank pin,
The connecting rod and the connecting rod become substantially straight, and the moving distance of the movable plate with respect to the change in the rotation angle of the crank is extremely reduced.
Therefore, in this state, the rotational force of the crank is converted into a large clamping force. Therefore, when resin molding is performed in a molding die that is in a mold-clamped state when the crank pin moves to the vicinity of the dead center, the resin is molded while being clamped by a large force.

[Item 2] In the above item 1, "the crank mechanism is driven by a motor, and a stop means for stopping the rotation of the motor when the crank pin moves to the vicinity of the dead center is provided." In this case, when the crank pin moves to the vicinity of the dead center, the rotation of the motor, which is the drive source of the crank mechanism, is stopped by the stop means. This allows
The movable mold is kept in the mold clamped state, and in this state, it is possible to wait until the plasticized resin injected into the mold hardens.

[3] In the above item [1] or [2], "the connection point between the connecting rod of the crank mechanism and the movable platen is on a straight line extending in a mold clamping direction from a rotation center of a crank constituting the crank mechanism. Is larger than that in the case where the connecting point of the connecting rod to the movable plate is not located on a straight line extending in the mold clamping direction from the rotation center of the crank. In the former case, when the crank pin is moved to the dead center, the moving distance of the movable plate with respect to the rotation angle of the crank is shorter than that in the latter case, whereby the rotational force of the crank is converted into a large tightening force. Because.

[4] In the above items [1] to [3], it is preferable that "the movable plate is provided with a final mold clamping device for pushing the movable mold in a mold clamping direction, and the crank pin is connected to the dead center. A control device for closing the movable mold by operating the final mold clamping device before or before moving to the vicinity is provided. ' The final clamping device is activated when or before it moves. That is, every time the crank pin reaches a position near the dead center, that is, each time the mold clamping operation is performed, the final mold clamping device operates. Then, the movable mold is pushed out in the mold clamping direction by the operation of the final mold clamping device, and the movable mold is pushed into the mold clamping state. By adjusting the distance by which the movable mold is pushed out by the tightening device (the pushing distance after the crank pin reaches the vicinity of the dead center or the like), it is possible to cope with the mold thickness change.

[5] The method according to the above [4], wherein the final mold clamping device is a feed screw mechanism driven by a motor and having an output portion connected to a mold mounting plate for fixing the movable mold. In this case, the movable die is pressed together with the die mounting plate in the die clamping direction at the output portion of the feed screw mechanism constituting the final die clamping device to clamp the die.

[6] The method according to the above [4], wherein the final mold-clamping device has a force point connected to an output portion of a linear motion mechanism provided on the movable platen, and a mold attachment for fixing the movable mold. A link type booster mechanism comprising an operation point connected to a plate, and a fulcrum positioned opposite to the force point across the operation point and rotatably supported by a fixed portion of the movable platen. ]
When the linear motion mechanism operates, the point of force of the link type booster mechanism connected to the output portion thereof is pushed in the mold clamping direction. Then, the mold mounting plate (where the movable mold is mounted) is pushed out in the mold clamping direction at the point of action of the link type booster mechanism. Then, the reaction of the force of the action point pressing the movable mold attached to the mold attachment plate in the mold clamping direction is received by the fixed portion of the movable plate supporting the fulcrum. At this time, since the distance between the fulcrum and the point of force is greater than the distance between the fulcrum and the point of action, the output of the linear motion mechanism is amplified and transmitted to the movable mold by the principle of leverage. Is clamped by a large force.

[0013]

According to the present invention having the above configuration, the following specific effects are obtained. According to the first to third aspects of the present invention, the mold clamping operation and the high-speed opening and closing operation can be performed only by controlling the rotation angle and the rotation speed of the crank. There is no need to control a number of control valves in a hydraulic circuit provided for expanding and contracting the (17) and the mold clamping cylinder (18) while considering the operation timing. Therefore, in the present invention, the control system of the mold clamping device can be simplified while ensuring high-speed operation. In addition, a large mold clamping force can be secured only by rotating the crank, and a high-speed mold opening / closing operation can be performed. Therefore, as described above, the mold opening / closing high-speed cylinders (17) (17) and the mold clamping are performed. It is not necessary to provide a separate mold clamping cylinder (18), and there is no need for a hydraulic pump or a hydraulic pipe for operating these cylinders, so that the size of the entire apparatus can be reduced.

In the invention of the fourth aspect, since the final mold clamping device which operates when clamping the movable mold is provided, if the thickness of the mold changes due to the exchange of the molding die, the final mold clamping position is changed. By adjusting the actuation amount, an effect that can cope with a change in the mold thickness can be further obtained.

In the invention of the fifth aspect, since the final mold clamping device is driven by the motor, the assembling work can be performed more easily than when a hydraulic cylinder requiring a hydraulic pipe is used.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described together with the illustrated example. FIG. 1 is a side view of a partially cut-away part of a mold clamping device for a molding die according to an embodiment of the present invention. In this device, a frame (3) consisting of a base (40), four columns (39) (39) erected on the outer periphery of an upper surface thereof, and a ceiling (35) supported at an upper end thereof, A movable plate (34) that moves up and down along a tie bar (31) (31) erected between the base (40) and the ceiling portion (35) and includes a final mold clamping device; ) Is provided with a crank mechanism (50) for moving up and down along the tie bars (31) and (31).

The details of each section will be described below. [About the frame (3)] The base (4
0) is formed in a square shape in plan view, and columns (39) and (39) are erected at four corners thereof. And the pillar
(39) The ceiling (35) is supported at the upper end of (39). A parallel tie bar (31) (3) is provided between the ceiling (35) and the base (40).
1) is erected. In addition, the movable platen described later is
Locking devices (55) and (55) for preventing the (34) from rising from the mold clamping position are attached, and the locking devices (5
5) and (55) are provided with lock pins (79) and (79) that can move forward and backward.

[About movable plate (34)] The tie bar (31)
The movable platen (34) ascending and descending along (31) is formed in a rectangular box shape as a whole, and has an upper plate portion (56) and a lower plate portion (5).
7) has an insertion hole (5) for inserting the tie bar (31) (31).
60) (560) (570) (570) are formed. Also, a mold mounting plate (42) is located in a square window (58) opened in the center of the lower plate portion (57), and the mold mounting plate (42) is provided with a feed screw mechanism (60). It is made to go up and down at (60).

Each of the feed screw mechanisms (60) includes a ball nut (43) rotatably mounted on the upper plate (56) of the movable plate (34).
And a pulley (4
4), wherein the pulley (44) is connected to a rotating shaft of a ball screw servomotor (46) via a transmission belt (47), and the ball screw servomotor (46) is attached to a mounting bracket.
It is fixed to the upper plate portion (56) at (45). Further, the lower end of the ball screw shaft (59) screwed into the ball nut (43) is fixed to the mold mounting plate (42) via a connection fitting (48). In the present embodiment, the ball screw servomotor (4
The combination of (6) (46) and the feed screw mechanism (60) (60) driven by this corresponds to the final mold clamping device described above. A movable die (33) is fixed to the die mounting plate (42) with bolts (36) (36). The movable mold (33) is attached to the mold mounting plate (42) by using a clamper (not shown).
The clamper and the bolts (36) (36) are configured to be selectively used as appropriate.

[Regarding Crank Mechanism (50)] Frame
In the lower base (40) of (3), a space for arranging a crank wheel (51) and the like constituting the above-described crank is formed, and the crank wheel (51) is mounted on a wheel mount ( 52)
It is rotatably mounted on. The crank wheel (51) is connected to a rotating shaft of a crank servo motor (54) via a transmission belt (53).

On the outer peripheral portion of the crank wheel (51),
The lower end of the connecting rod (62) is rotatably connected by a crank pin (61), and the upper end of the connecting rod (62) is erected on the upper plate (56) of the movable plate (34). The bracket (63) is rotatably connected with a support shaft (64). And in this embodiment,
A support shaft (64) located at the connection point between the connecting rod (62) and the movable plate (34)
Are arranged on a vertical line extending vertically (in the mold clamping direction) from the rotation center (69) of the crank wheel (51).

Also, a mold mounting block (37) on the upper surface of the base (40).
Is fixed with bolts (38) and (38).
The fixed die (32) can be mounted and fixed to the die mounting block (37) also by using a clamper (not shown), and the clamper and the bolts (38) (3)
8) is configured to be selectively used as appropriate.
It is sufficient that at least one crank mechanism (50) is provided, but two or more crank mechanisms (50) that are separately connected to both sides of the movable platen (34) are provided. May be.

[Operation] A control device (not shown) incorporated in the mold clamping device of the above molding die incorporates a programmable logic controller in which a control command shown in FIG. 2 is stored in this embodiment. ,Less than,
The actual operation of the mold clamping device will be described with reference to the flowchart of FIG. In step (ST1), the origins of the servo motor for crank (54) and the servo motor for ball screw (46) are aligned, whereby the movable mold (33) is set to the initial position as the mold opening position.

Next, the output of a mold-clamping start signal from a product take-out device (not shown) is monitored in step (ST2), and when the mold-clamping start signal is generated, in step (ST3), the crank servomotor (54) is output. To rotate. And the crankpin
Whether the crank servo motor (54) has been rotated until (61) reaches a position slightly above the bottom dead center (it may be at or slightly before the bottom dead center) It is determined in step (ST4) that when the crank pin (61) reaches a position slightly beyond the bottom dead center, the crank servo motor (54) is stopped (see step (ST5)). still,
In the present embodiment, the functional unit of the control device for stopping the crank servo motor (54) corresponds to the above-mentioned "stop means for stopping the rotation of the servo motor".

In this state, the movable mold (33) is lowered to the mold-clamp preparation position, which is approached at a slight distance from the fixed mold (32), and in this state, the movable plate (34) is locked. It has descended slightly below the location of the device (55). Then, the step (ST6) is executed to activate the lock devices (55) and (55), thereby moving the lock pins (79) and (79) to the movable platen (34).
Project into the space above.

Next, the process waits for the injection of the plasticizing resin from the injection machine (not shown) into the cavity of the molding die composed of the movable die (33) and the fixed die (32). When the signal is output from the injection machine, the control operation shifts from step (ST7) to step (ST8) to operate the ball screw servomotors (46) and (46) exhibiting a large rotational torque. Then, the movable mold (33) attached to the mold attaching plate (42) of the movable board (34) comes closer to the fixed mold (32) and is clamped with a large force. At this time, the movable plate (34) comes into contact with the lock pins (79) and (79) of the lock devices (55) and (55) projecting upward from below, thereby preventing the movable plate (34) from moving backward in the mold clamping direction. As a result, the reaction of the mold clamping force is received by the lock pins (79) and (79). Then, the plasticizing resin in the cavity is compressed by the mold clamping, and is spread over the entire cavity. Therefore, in the present embodiment, the zone from when the movable mold (33) starts compressing the plasticized resin to when the movable mold (33) descends and reaches the lowest position corresponds to the mold clamping position described above.

Next, a wait is carried out until the plasticized resin in the cavity of the mold is cured (see step (ST9)), and then the lock pins (79) (7) of the lock devices (55) (55) are executed.
9) is retracted, whereby the lock pins (79) and (79) are retracted to a position outside the space above the movable plate (34) (step (ST10)). Then, since the movable platen (34) can be raised to the initial mold opening position, the control operation is returned to step (ST1) again, and the ball screw servomotors (46) (46) and the crank servomotor (54) are returned. Rotate to the initial position,
Thereby, the movable platen (42) is returned to the mold opening position, which is the initial position. When the movable platen (42) in the mold clamping position is returned to the above-mentioned mold opening position, it is necessary to use a crank servomotor.
After rotating the crank wheel (51) to the initial position in (54), the ball screw servomotors (46) and (46) may be operated to return the final mold clamping device to the initial state. Conversely, after returning the final mold clamping device to the initial state, the crank wheel (51) may be rotated to the initial position, and furthermore, by operating these final mold clamping device and the crank wheel (51) simultaneously. The movable plate (42) may be returned to the initial position.

[Modification of Final Mold Clamping Apparatus] FIG. 3 is an explanatory view of a modification of the final mold clamping apparatus. The lower opening of an empty space (71) formed in the movable platen (34) that moves up and down along the tie bars (31) and (31) is closed by a mold mounting plate (42), and On the upper surface of the mounting plate (42), rails (91) and (91) extending in the left-right direction with respect to the paper surface of FIG. A connecting pin (8) is attached to the lower end of the ball screw shaft (81) described later.
2) Tip rollers (93) and (93) provided at the tips of the levers (92) and (92) connected by (82) are recessed portions formed on both side walls as fixed portions of the empty room (71). (96) It is inserted into (96) and is in a state of being rotatably supported. The center rollers (97) and (97) attached to the middle of the lever (92) in the longitudinal direction (may be any distance between the connecting pin (82) and the tip roller (93)) are connected to the rail (91). ) (91) can be moved while being sandwiched from above and below by an upper plate (94) and a lower plate (95). In the present embodiment, the arrangement positions of the connection pin (82), the tip roller (93), and the center roller (97) correspond to the force points, the fulcrums, and the action points, respectively.

The ball screw shaft (81) to which the upper ends of the levers (92) and (92) are connected is screwed into a ball nut (84), and the ball nut (84) is connected to the movable plate (34). Upper plate (56)
It is attached to the central part via bearings (87) and (87).
A pulley (73) is fixed to the upper end of the ball nut (84) with bolts, and the pulley (73) is
Through a shaft of a servomotor (75) for a ball screw. In this case, the combination of the ball nut (84) and the ball screw shaft (81) corresponds to the linear motion mechanism described in the above-mentioned item 6, and the lower end of the ball screw shaft (81) and the concave portions (96) (9)
The levers (92) and (92) provided to connect 6) correspond to the link-type booster mechanism described in the above-mentioned item 6. The movable plate (34) is raised and lowered along the tie bars (31) and (31) by the same link mechanism as in FIG.

In this case, when the ball screw servomotor (75) operates in the state shown by the solid line in FIG. 3 (the state where the crankpin of the crank mechanism is located near the dead center), the rotational force is transmitted to the transmission belt ( 74) is transmitted to the ball nut (84) via the pulley (73), which rotates,
The ball screw shaft (81) descends. Then, the ball screw shaft (8
Due to the descending force of 1), the portions of the connecting pins (82) and (82) located at the point of force of the levers (92) and (92) are pushed downward,
The levers (92) and (92) rotate around the leading end rollers (93) and (93) invading the concave portions (96) and (96). The connecting pin (82)
When the lever (82) is pushed downward and the levers (92) and (92) rotate, the center rollers (97) and (97) located at the point of action are
Is pressed down, whereby the movable mold (33) is pushed toward the fixed mold (32) side to clamp the mold. At this time, since the center roller (97) is provided between the connecting pin (82) and the tip roller (93),
By the principle of leverage, the descending force of the ball screw shaft (81) is amplified and transmitted to the mold mounting plate (42), whereby the movable mold (33) is clamped with a large force. In FIG. 3, the ball nut (84) is rotated by the ball screw servomotor (75). However, the ball nut (84) is arranged in a fixed state, and the ball screw shaft (81) is It may be rotated by a motor (75).

[Others] In the above embodiment, the movable mold (33) moves closer to the fixed mold (32) while compressing the plasticized resin in the cavity, but the movable mold (33) and the fixed mold (32) The movable platen (34) may be lowered by the crank mechanism (50) until the mold is completely closed, and in this state, the plasticizing resin may be injected into the cavity to operate the final mold clamping device. Alternatively, the plasticizing resin may be injected into the cavity after the movable mold (33) is pressed toward the fixed mold (32) with a large clamping force by operating the final mold clamping device. In these cases, the position of the movable mold (33) when the mold is completely closed corresponds to the mold clamping position described above.

[0032] After starting injection of the plasticized resin into the cavity of the mold, the movable platen (34) is locked by the lock device (55) (55)
It is also possible to prevent the ascending movement by the lock pins (79) and (79) and to compress the plasticized resin in the cavity. During the compression, the operation of injecting the plasticized resin into the cavity may be continued or may be stopped.

[0033] In the above-described embodiment, the present invention is applied to the vertical mold clamping device to clamp the molding die in the vertical direction. However, the mold clamping direction does not necessarily need to be set to the exact vertical direction. May be inclined with respect to the direction,
Further, it may be set in the horizontal direction. That is, in the present invention, the mold clamping direction is not limited to a specific direction, and can be appropriately selected according to the work situation and the like.

[0034] As a molding die composed of the movable die (33) and the fixed die (32), a wooden die or a resin die can be used in addition to the metal die.

[0035] In the above embodiment, the movable platen (34) lowered to the mold clamping position is the lock pin (7) of the lock device (55) (55).
9) Make contact with (79) from below, thereby
Although the movable platen (34) is prevented from retreating in the mold opening direction, the movable plate (34) is prevented from retracting in the mold opening direction by using a brake (not shown) of the crank wheel (51). It may be.

[0036] In the above embodiment, the movable platen (34) is provided with the final mold clamping device, but when the crankpin (61) reaches the vicinity of the bottom dead center, the movable mold (33) and the fixed mold (32) are separated. If the mold can be brought close to the moldable state, it is not always necessary to provide the final mold clamping device. When the crank pin (61) moves to the vicinity of the bottom dead center, the rotation center (6
Since the straight line connecting 9) and the crank pin (61) is almost straight with the connecting rod (62), the moving distance of the movable platen (34) with respect to the change in the rotation angle of the crankwheel (51) is extremely small and large. This is because a mold clamping force can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a mold clamping device for a molding die according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a control operation of a mold clamping device for a molding die according to an embodiment of the present invention.

FIG. 3 is an explanatory view of a modification of the final mold clamping device.

FIG. 4 is an explanatory view of a conventional example.

[Explanation of symbols]

 (34) ・ ・ ・ Movable plate (33) ・ ・ ・ Movable type (32) ・ ・ ・ Fixed type (50) ・ ・ ・ Crank mechanism (60) ・ ・ ・ Feed screw mechanism (61) ・ ・ ・ Crank pin

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takeo Kitayama 2-10-1 Tsukahara, Takatsuki-shi, Osaka Sumitomo Chemical Industries Co., Ltd. (72) Inventor Akihiro Furuta 2-1-1 Tsukahara, Takatsuki-shi, Osaka Sumitomo Chemical Industries Co., Ltd. F term (reference) 4F202 AR02 CA09 CA11 CB01 CL01 CL22 CL37 CL39 4F206 AR024 JA07 JM02 JN34 JP18 JQ83 JT05 JT32 JT38

Claims (6)

[Claims] 1. A movable plate attached to the movable plate is reciprocated between a mold opening position and a mold clamping position by reciprocatingly driving the movable plate. At the mold clamping position, the movable die is larger on the fixed mold side. In a mold clamping device of a molding die pressed by a mold clamping force, the movable plate is configured to be reciprocally driven in a mold clamping direction by a crank mechanism, and the crank mechanism moves when a crank pin moves to near a dead center. Wherein the movable mold is configured to reach the mold clamping position. 2. The mold clamping device according to claim 1, wherein the crank mechanism is driven by a motor, and stops the rotation of the motor when the crank pin moves to the vicinity of the dead center. A mold clamping device provided with a stopping means. 3. The mold clamping device according to claim 1, wherein a connecting point between the connecting rod of the crank mechanism and the movable platen is:
A mold clamping device for a molding die, which is located on a straight line extending in a mold clamping direction from a rotation center of a crank constituting the crank mechanism. 4. The mold clamping device according to claim 1, 2 or 3, wherein the movable platen is provided with a final mold clamping device for pushing the movable mold in a mold clamping direction. And a control device for operating the final mold clamping device to clamp the movable mold when or before the crank pin moves to the vicinity of the dead center. 5. The mold clamping device according to claim 4, wherein the final clamping device is driven by a motor and has an output portion connected to a mold mounting plate for fixing the movable mold. A mold clamping device that is a screw mechanism. 6. The mold clamping device according to claim 4, wherein the final mold clamping device comprises: a power point connected to an output portion of a linear motion mechanism provided on the movable plate; A link comprising an operation point connected to a mold mounting plate for fixing a mold, and a fulcrum located on the opposite side of the force point across the operation point and rotatably supported by a fixed portion of the movable platen. It is a type booster mechanism,
Mold clamping device.