JPH0966549A - Method for adjusting posture of link of toggle type mold clamping apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve the conservation of drive energy during a mold clamping period and the accurate reproduction of set mold clamping force. SOLUTION: A toggle link 6 is arranged on one straight line at a time of the completion of mold clamping and mold clamping reaction force and resin reaction force are received along the axial line of a ternary link 3 to eliminate the rotary moment around a node 15 and the external force for holding the posture of the ternary link 3 is despensed with. The spaced-apart distance between a rear platen 2 and a moving platen 4 at the time of the completion of mold clamping is always made constant regardless of the mold clamping reaction force and the extension of a tie bar 10 determined by the position of the rear platen 2, mold thickness and the inherent spaced-apart distance between the rear platen 2 and the moving platen 4 is accurately reproduced. Since the toggle link 6 is linearly held, a crosshead 7 is further thrust out from a reference position by the correction quantity Δx of the position of the crosshead corresponding to set mold clamping force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a link attitude adjusting method for a toggle type mold clamping device.

[0002]

2. Description of the Related Art A toggle type mold clamping device is known in which a toggle link is bent and stretched by a linear movement of a crosshead to perform a mold opening and a mold clamping operation. FIG. 1A shows a general configuration example of a toggle type mold clamping device. In addition,
In FIG. 1A, the main part of the toggle type mold clamping device 1 is shown only on one side with respect to the central axis CL thereof.

As shown in FIG. 1A, a toggle type mold clamping device 1 includes a ternary link 3 pivotally attached to a rear platen 2.
And a toggle link 6 composed of a binary link 5 pivotally attached to the moving platen 4 and a ternary link 3
And a crosshead link 8 that connects the pivot point of the binary link 5 to the crosshead 7, a ball screw 9 that linearly feeds the crosshead link 8, and a ball screw 9 that is attached to the rear platen 2 to drive the ball screw 9 to rotate. It is composed of a mold clamping servomotor (not shown).

That is, the moving platen 4 having the movable mold 12a mounted thereon is moved along the tie bar 10 by linearly feeding the cross head 7 by driving the mold clamping servo motor to bend and extend the toggle link 6. It is common in a toggle type mold clamping device to perform a predetermined mold opening and mold clamping operation between the fixed side mold 12b mounted on the stationary platen 11 and the movable side mold 12a mounted on the moving platen 4. It is a simple structure.

FIG. 1A shows an electric toggle type mold clamping device 1 using a mold clamping servomotor, a ball screw, etc., but the crosshead 7 is linearly fed by a hydraulic ram or the like. There is also a hydraulic toggle-type mold clamping device. Both have the same basic operating principle.

In the toggle type mold clamping device 1, the toggle link 6 is formed in a state where the ternary link 3 and the binary link 5 forming the toggle link 6 are completely aligned as shown in FIG. 1 (a). It is configured so that the amplification factor of the force is maximized, and it is naturally desirable that the toggle link 6 is kept in this state even at the stage of completion of mold clamping.

As a result, the distance between the rear platen 2 and the moving platen 4 corresponding to the optimum mold clamping completion state is determined by the lengths of the ternary link 3 and the binary link 5 and the center when these are aligned. It is uniquely determined by the inclination of the toggle link 6 with respect to the line CL and cannot be changed.

Therefore, the die thickness, that is, the movable die 12a
Depending on the sum of the thickness of the fixed side mold 12b and the thickness of the fixed side mold 12b, the rear platen 2 is moved toward or away from the stationary platen 11 as a whole, and the mold clamping is completed with the toggle links 6 completely aligned. It is necessary to determine the position of the rear platen 2 so that This is the mold thickness adjustment.

As means for moving the rear platen 2 toward and away from the stationary platen 11, screw parts 13 engraved at each end of the four tie bars 10 and four corners of the rear platen 2 are provided. Each of the screw parts 1 is attached so as to be rotatable and immovable in the axial direction.
There are four tie bar nuts 14 screwed onto the three. That is, by synchronously rotating these four tie bar nuts 14 by a mold thickness adjusting motor (not shown) attached to the rear platen 2 side, the rear platen 2 is moved toward and away from the stationary platen 11. -ing

Further, in the toggle type mold clamping device 1, the mold clamping force can be adjusted by utilizing the above-mentioned mold thickness adjusting function. That is, since the distance between the rear platen 2 and the moving platen 4 corresponding to the optimum mold clamping completed state is uniquely determined, the distance between the rear platen 2 and the stationary platen 11 is maintained,
In short, if the extension amount of the tie bar 10 at the time of completion of mold clamping is changed, the set mold clamping force can be freely adjusted within the range of the maximum mold clamping force.

More specifically, first, the movable side mold 12a is fixed side mold 1 in a state where the ternary link 3 and the binary link 5 are completely aligned in an unloaded state.
The position of the rear platen 2 with respect to the stationary platen 11 is determined so as to be in close contact with the stationary platen 11, and the rear platen 2 is moved closer to the stationary platen 11 by the amount of extension of the tie bar 10 corresponding to the set mold clamping force described above. The position of is the rear platen position corresponding to the set mold clamping force.

It should be noted that various process operations including detection of the die touch position are carried out in actual die thickness adjustment and die pressure setting, but the general outline is as described above, and in short , The rear platen position for realizing the set mold clamping force is the following three elements, that is, the distance between the rear platen 2 and the moving platen 4 (= the ternary link 3 The distance between the rear platen 2 and the moving platen 4 when the binary links 5 are completely aligned with each other), the extension amount of the tie bar 10 (= a value corresponding to the set mold clamping force), and the mold thickness ( It can be determined by the sum of the thicknesses of the movable die 12a and the fixed die 12b.

Among them, the distance between the rear platen 2 and the moving platen 4 corresponding to the optimum mold clamping completion state (= the rear platen 2 when the ternary link 3 and the binary link 5 are completely aligned). The distance from the moving platen 4) is an eigenvalue determined only by the structure of the toggle link 6.

Since it is necessary to move the moving platen 4 to open and close the mold, a reference position (origin position) for indicating the position of the moving platen 4 with respect to the rear platen 2 is set in the controller of the injection molding machine. Although it is necessary to store it in memory, there is no injection molding machine equipped with a means for directly detecting the distance between the rear platen 2 and the moving platen 4, and in reality, the mold clamping device 1 or the drive source A pulse coder or the like provided on the rotating portion will be used as position detecting means for the moving platen 4. The most common method is to replace the position detecting means of the moving platen 4 with a means for detecting the position of the crosshead 7 with respect to the rear platen 2, that is, a pulse coder or the like for detecting the rotational position of the mold clamping servomotor. is there.

Therefore, the reference position of the moving platen 4 must also be memorized by the position of the crosshead 7, more strictly speaking, the rotational position of the mold clamping servomotor.

Therefore, in the conventional injection molding machine, it is assumed that the position of the cross head 7 with respect to the rear platen 2 and the position of the moving platen 4 with respect to the rear platen 2 always correspond one-to-one with each other.
That is, the position of the crosshead 7 when the ternary link 3 and the binary link 5 are completely aligned in a straight line with no mold clamping reaction force acting on the toggle link 6 is the reference position (origin position) of the moving platen 4. It was made to be memorized in the control device as.

Since this reference position (origin position) is a value that should correspond to the mold clamping completion position of the moving platen 4, it has no relation to the set mold clamping force, and as mentioned above, this reference position (origin position) is always maintained at the completion of the mold clamping. The crosshead 7 is projected to the reference position (origin position). However, when the set mold clamping force becomes large, the crosshead 7 is moved to the reference position (origin position).
Even if it is made to project even to (1), the ternary link 3 and the binary link 5 are not always completely aligned.

One of the causes is the frictional resistance around the node 15 located at the pivot point between the rear platen 2 and the ternary link 3.

As shown in FIG. 1B, the node 15 is
The bush 17 fixedly fitted inside the end of the ternary link 3 and fixed to the rear platen 2 side.
When the movable mold 12a and the fixed mold 12b actually make contact with each other and the mold clamping operation is started, the ternary link 3 has its shaft. A strong mold clamping reaction force f1 acts along the direction, a part of the inner peripheral surface of the bush 17 is pressed against a part of the outer peripheral surface of the pin 16, and a strong vertical reaction force acts on this pressed contact part. Become. At this time, at the tip of the ternary link 3,
Although the swinging force in the UC direction given from the crosshead 7 via the crosshead link 8 is acting, the frictional resistance f2 obtained by multiplying the frictional coefficient between the pin 16 and the bush 17 by the above-mentioned vertical reaction force is ternary. Anti-UC at the base side of link 3
Since the ternary link 3 does not rotate sufficiently or is deflected due to the directional action, the ternary link 3 and the binary link 5 can be protruded to the reference position (origin position). The phenomenon occurs that and are not perfectly aligned.

Of course, a similar phenomenon may occur around the node 18 located at the pivot point between the moving platen 4 and the binary link 5.

Thus, when the projecting operation of the crosshead 7 to the reference position (origin position) is completed while the ternary link 3 and the binary link 5 are still bent, as shown in FIG. 1 (b). In addition, the ternary link 3 cannot directly receive the mold clamping reaction force acting in the axial direction of the binary link 5 along the axial direction, and the pivot point of the ternary link 3 and the binary link 5 is In the portion of the node 19 that constitutes the portion, the force that pushes this portion toward the central axis CL, that is, the crosshead 7
The force to move the mold toward the rear platen 2 acts on the whole mold clamping process. In order to prevent the retreat of the crosshead 7 due to the resin reaction force at the time of injection pressure holding, that is, inadvertent opening of the mold, the mold clamping servomotor must be driven during the entire mold clamping process. There is a problem that power consumption increases.

As described above, the rear platen position for realizing the set mold clamping force is the distance between the rear platen 2 and the moving platen 4 (= the ternary link 3 The distance between the rear platen 2 and the moving platen 4 when the binary links 5 are completely aligned with each other), the extension amount of the tie bar 10 (= a value corresponding to the set mold clamping force), and the mold thickness ( Although it is determined by the sum of the thicknesses of the movable side mold 12a and the fixed side mold 12b), the ternary link 3 and the binary link 5 are completely formed even if the crosshead 7 is projected to the reference position (origin position). When not aligned on a straight line,
Since the actual distance between the rear platen 2 and the moving platen 4 is smaller than the value used when calculating the rear platen position corresponding to the set mold clamping force, the extension of the tie bar 10 is insufficient. There is also a problem that the set mold clamping force cannot be obtained.

[0023]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to increase the mold clamping force or to change the set mold clamping force variously during the mold clamping period. It is an object of the present invention to provide a method for adjusting the link posture of a toggle type mold clamping device, in which the energy consumption of the drive source in the above-mentioned item is not wasted and the set mold clamping force can be obtained accurately.

[0024]

SUMMARY OF THE INVENTION According to the present invention, a crosshead reference position in which toggle links are aligned in a straight line in an unloaded state, and toggle links are aligned in a straight line against a mold clamping reaction force according to a mold clamping force. And a crosshead position correction amount for causing the crosshead position correction amount to be stored in advance, and according to the set mold clamping force, the crosshead position correction amount corresponding to the set mold clamping force is added to the crosshead reference position to complete the crosshead protrusion. The object is achieved by a structure characterized in that a mold clamping operation is performed as a position.

Further, a rotary position detector for detecting the refraction state of the toggle link is provided so that the crosshead is projected to a crosshead reference position where the toggle links are aligned in a straight line in a preset no-load state during mold clamping. After that, detecting the refraction state of the toggle link by the rotational position detector,
The same object was achieved by a configuration characterized in that the crosshead was projected to perform the mold clamping operation until the toggle links were aligned.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the link attitude adjusting method of the present invention will be described below with reference to the drawings. It should be noted that no new constituent elements are required for the structure of the mechanical unit of the toggle type mold clamping device, and the same structure as the toggle type mold clamping device 1 shown in FIG. A description of the mechanical structure is omitted. Of course, instead of the four-point toggle link 6 shown in FIG. 1A, etc., a five-point toggle link (not the pivotal connection between the ternary link 3 and the binary link 5 but the side of the ternary link 3 is crossed). There is no problem even if the head link 8 whose tip is pivotally attached) is applied.

However, in the toggle type mold clamping device 1 applicable to this embodiment, as shown in FIG. 1A, the ternary link 3 and the binary link 5 are perfectly aligned in a straight line. Then, the crosshead link 8 and the mold clamping device 1
It is necessary that the angle θ formed by the central axis CL of and does not exceed 90 °.

FIG. 4 is a block diagram showing a main part of a numerical control device 100 as a control device for driving and controlling each part of the toggle type mold clamping device 1 and the electric injection molding machine to which the mold clamping device 1 is attached.

The numerical control device 100 includes a CNC CPU 115 which is a numerical control microprocessor, a PMC CPU 108 which is a programmable machine controller microprocessor, a servo CPU 110 which is a servo control microprocessor, and an A / D. It has a CPU 107 for pressure monitoring for detecting injection pressure and screw back pressure from the pressure detector on the main body of the injection molding machine through the converter 106 and performing sampling processing.
Information can be transmitted between the respective microprocessors by selecting mutual input / output via 2.

The PMC CPU 108 is connected to the ROM 103 storing a sequence program for controlling the sequence operation of the injection molding machine and the RAM 104 used for temporary storage of operation data, and the CNC CPU 115.
A ROM 117 that stores an automatic operation program that controls the injection molding machine as a whole and a RAM 118 that is used for temporary storage of calculation data are connected to the.

Further, each of the servo CPU 110 and the pressure monitoring CPU 107 relates to a ROM 111 storing a control program dedicated to servo control, a RAM 109 used for temporary storage of data, and a sampling process of injection pressure and screw back pressure. A ROM 101 storing a control program and a RAM 102 used for temporary storage of data are connected. Furthermore, the servo CPU1
A servo amplifier for driving a servo motor for each axis for mold clamping, injection, screw rotation, ejector, etc. is connected to 10 based on a command from the CPU 110, and is attached to the servo motor for each axis. The output from the pulse coder is fed back to the servo CPU 110. The current position of each axis is calculated by the servo CPU 110 based on the feedback pulse from the pulse coder,
It is updated and stored in the current position storage register of each axis. In FIG. 4, only the servo amplifier 105 for one axis, the mold clamping servomotor M1 for driving the ball screw 9 of the mold clamping device 1 and the corresponding pulse coder P1 are shown. The axes are all similar in construction. However, it is not necessary to detect the current position for the screw rotation type, but only the speed. Further, a mold thickness adjusting motor (not shown) for synchronously rotating the four tie bar nuts 14 via a timing belt, a gear or the like is a normal induction motor,
A pulse coder for detecting the rotational position is provided.

The interface 113 is an input / output interface for receiving signals from limit switches and operation panels provided in various parts of the injection molding machine main body and for transmitting various commands to peripheral equipment of the injection molding machine. The interface for the amplifier for driving the mold thickness adjusting motor and the pulse coder for detecting the rotational position thereof
3 and is controlled by the numerical controller 100.

Manual data input device 119 with display
Is connected to the bus 112 via a CRT display circuit 116 so that a graph display screen, a function menu can be selected, various data input operations can be performed, and a numeric keypad for inputting numerical data and various function keys can be used. It is provided.

The non-volatile memory 114 is a memory for storing molding data for storing molding conditions and various set values, parameters, macro variables, etc. relating to injection molding work. In the present embodiment, in addition to these data, A file of the crosshead position correction amount according to the set mold clamping force (see FIG. 5) and the like are stored in the non-volatile memory 114. The setting of the reference position (origin position) of the moving platen 4 is exactly the same as that of the conventional toggle type mold clamping device, and the ternary link 3 and the binary link 3 are combined with the mold clamping reaction force not acting on the toggle link 6. The rotation position of the mold clamping servomotor M1 corresponding to the position of the crosshead 7 when the link 5 and the link 5 are completely aligned is stored in the non-volatile memory 114 as the reference position (origin position) of the moving platen 4. .

With the above configuration, the PMC CPU 108
Controls the sequence operation of the entire injection molding machine, the CPU 115 for CNC distributes pulses to the servo motors of each axis based on the operating program of the ROM 117, the molding conditions of the non-volatile memory 114, etc. Based on the pulse-distributed movement commands and position and velocity feedback signals detected by detectors such as pulse coders, servo control such as position loop control, velocity loop control, and current loop control is performed in the same manner as in the past. Done,
A so-called digital servo processing is executed.

FIG. 2 is an explanatory view showing the outline of the processing operation for obtaining the crosshead position correction amount Δx according to the magnitude F of the set mold clamping force.

As shown in FIG. 2, in this embodiment, first, an appropriate movable mold 12a and fixed mold 12b are mounted on each of the moving platen 4 and the stationary platen 11 to adjust the mold thickness and mold. A pressure setting operation (in this case, the set mold clamping force is set to F) is performed, and the rear platen position corresponding to the set mold clamping force F is obtained in the same manner as in the conventional case. In other words, by the same mold touch position detection processing as in the related art, the movable side mold 1 is in a state in which the ternary link 3 and the binary link 5 are completely aligned in the unloaded state.
If the position of the rear platen 2 is determined so that 2a is in close contact with the fixed side mold 12b, and further the crosshead 7 is projected to the reference position (origin position), the turner irrespective of the magnitude F of the set mold clamping force is applied. Based on the assumption that the Re-link 3 and the binary link 5 are always aligned on a straight line, the rear platen 2 when the rear platen 2 is brought closer to the stationary platen 11 by the extension of the tie bar 10 corresponding to the set mold clamping force F. The position is determined as the rear platen position corresponding to the set mold clamping force F.

In FIG. 2, the rear platen 2 is actually moved to the obtained rear platen position, and further the mold clamping servomotor M1 is driven to project the crosshead 7 to the reference position (origin position). Shows the state,
The ternary link 3 and the binary link 5 are not aligned in a perfect straight line. This is, as I said,
This is because rotation of the ternary link 3 is insufficient due to frictional resistance around the node 15 located at the pivot point of the rear platen 2 and the ternary link 3.

Therefore, if this state is decided as the projection completion position of the crosshead 7, the ternary link 3 applies the mold clamping reaction force acting in the axial direction of the binary link 5 during mold clamping along the axial direction. It cannot be directly received and it is necessary to drive the mold clamping servomotor M1 through the whole mold clamping process in order to prevent inadvertent mold opening due to the resin reaction force during injection pressure holding. The problem arises. Further, when the ternary link 3 and the binary link 5 are not perfectly aligned on a straight line, the actual separation distance between the rear platen 2 and the moving platen 4 is the calculation of the rear platen position for obtaining the set mold clamping force F. Since it has become smaller than the value used when, the elongation of the tie bar 10 is insufficient and the set mold clamping force F
In some cases, there may be problems such as not being able to obtain.

Therefore, in this embodiment, from the reference position (origin position) of the crosshead 7 as shown in FIG.
Further, by operating the manual feed switch or the like, the mold clamping servomotor M1 is driven to cause the crosshead 7 to project, and the position of the crosshead 7 in which the ternary link 3 and the binary link 5 are completely aligned are detected. , The rotation amount of the mold clamping servomotor M1 corresponding to the movement amount (manual feed amount) of the crosshead 7 from the reference position (origin position) is crossed as the crosshead position correction amount Δx corresponding to the set mold clamping force F. The head position correction amount is stored in a file (see FIG. 5).

It has already been mentioned that the ternary link 3 and the binary link 5 can be aligned in a perfect straight line against the mold clamping reaction force by further projecting the crosshead 7 from the reference position (origin position). As described above, when the ternary link 3 and the binary link 5 are completely aligned in the unloaded state, the crosshead link 8 and the mold clamping device 1 are
This is because the angle θ formed with the central axis CL of does not exceed 90 °.

That is, as shown in FIG. 1B, when the toggle link 6 is subjected to a strong mold clamping reaction force, the rotation of the ternary link 3 is insufficient due to the frictional resistance around the node 15 described above. Therefore, even if the crosshead 7 is projected to the reference position (origin position),
Although the ternary link 3 and the binary link 5 are not necessarily aligned in a straight line as in the case of the unloaded state shown in FIG. 1A, in the configuration of this embodiment, the ternary link is in the unloaded state. Since the angle θ formed by the crosshead link 8 and the central axis CL of the mold clamping device 1 does not exceed 90 ° when the 3 and the binary link 5 are completely aligned, FIG. By further projecting the crosshead 7 from the reference position (origin position) shown in (b) and swinging the crosshead link 8 to separate the node 19 from the central axis CL to the outside, FIG. As shown, the ternary link 3 and the binary link 5 can be aligned on a straight line. FIG.
(A) and the amount of protrusion of the crosshead 7 from the reference position (origin position) shown in FIG. 1B (servo motor M1 for mold clamping).
Is the crosshead position correction amount Δx (see FIG. 1C) corresponding to the set mold clamping force F.

The magnitude of the frictional resistance f2 around the node 15 which influences the refraction state of the toggle link 6 in FIG. 1B is determined by the mold clamping reaction force acting on the toggle link 6, that is,
Since the set mold clamping force F changes variously, the maximum mold clamping force Fmax. Allowed in the mold clamping device 1 is set as the maximum value, and the set mold clamping force F is in the range of 0 tons to F1 tons and F1 tons. ... F2 tons, etc. are divided into a plurality of parts, and the average mold clamping force value in each range is set as the set mold clamping force F, and the same processing operation as described above is repeatedly executed to determine the range of each set mold clamping force. The value of the crosshead position correction amount Δx corresponding to is calculated for each, and the value is stored in a file of the crosshead position correction amount as shown in FIG. 5 in correspondence with the set mold clamping force range. To do.

Of course, the above is the processing operation necessary for creating the file of the crosshead position correction amount, and is basically performed by the manufacturer.

In the mold clamping control of the injection molding machine by the numerical controller 100, the corresponding crosshead position correction amount Δx is calculated from the crosshead position correction amount file based on the magnitude of the set mold clamping force F at that time. Read the crosshead 7 further from the above-mentioned reference position (origin position) by Δx.
By performing the mold clamping operation by projecting only the mold, the mold clamping servomotor M1 is driven and controlled so that the mold clamping is completed in a state where the ternary link 3 and the binary link 5 are completely aligned. In short, in the conventional mold clamping control, the crosshead 7 is projected from the set mold opening completion position to the above-mentioned reference position (origin position) to perform the mold clamping operation. From the reference position (origin position) of the crosshead 7 by Δx
This means that the pulse distribution for the mold clamping is performed with the position where the is projected as the target position.

According to this configuration, the posture of the toggle link 6 at the time of completion of the mold clamping is always in a straight line regardless of the magnitude of the set mold clamping force. Therefore, the mold clamping reaction force acting in the axial direction of the binary link 5 is obtained. Always acts along the central axis of the ternary link 3. Therefore, no rotational moment about the node 15 is generated in the ternary link 3, and there is no need to support the tip of the ternary link 3 from the side of the central axis CL by the crosshead link 8.
As a result, it is not necessary to drive the mold clamping servomotor M1 during the mold clamping period to prevent the crosshead 7 from retracting, and power saving is achieved. Further, since the ternary link 3 and the binary link 5 are completely aligned on a straight line when the mold clamping is completed, the actual separation distance between the rear platen 2 and the moving platen 4 at the completion of the mold clamping is the mold clamping force. Since the eigenvalue used for setting (calculation of the rear platen position) always matches, the problem of insufficient elongation of the tie bar 10 can be solved, and the set mold clamping force can be accurately reproduced.

When looking only at the crosshead link 8 which forms part of the booster, the rotational position of the crosshead link 8 where the amplification factor of the force is maximum is shown in FIG. 1 (c).
(2), that is, the position when the crosshead link 8 is orthogonal to the central axis CL. Needless to say, the mold clamping reaction force does not act on the crosshead link 8 as long as the ternary link 3 and the binary link 5 are aligned, regardless of the rotational position of the crosshead link 8 (for example, FIG. 1). (State shown in (a)), since it is necessary to push the node 19 outward from the central axis CL by the rotation operation of the crosshead link 8 during the period from the start of mold clamping to the completion of mold clamping, In the case where the set mold clamping force is large, it is advantageous that the crosshead link 8 is in the vicinity of the rotational position shown in FIG. 1C in the process from the start of mold clamping to the completion of mold clamping. . Therefore,
When considering the power consumption from the start of mold clamping to the completion of mold clamping, the ternary link 3 and the binary link 5 are connected with the mold clamping reaction force corresponding to the maximum mold clamping force Fmax. It is most preferable that the cross head link 8 is orthogonal to the central axis CL in a state where the lines are completely aligned. Therefore, inevitably, when the ternary link 3 and the binary link 5 are completely aligned in the unloaded state, the angle θ formed between the crosshead link 8 and the central axis CL of the mold clamping device 1 is as shown in FIG. 90 as shown in (a)
However, if the set mold clamping force is small, the node 19
Since less force is required to push the shaft outward from the central axis CL, the crosshead link 8 is substantially oblique to the central axis CL in the process from the start of mold clamping to the completion of mold clamping. However, there is no particular problem.

Further, it is not always necessary to determine the state where the ternary link 3 and the binary link 5 are lined up in a straight line in the unloaded state as the reference position (origin position) of the crosshead 7, and for example, the maximum mold clamping force. The state where the ternary link 3 and the binary link 5 are completely aligned in a straight line with the mold clamping reaction force corresponding to Fmax. Acting is defined as the reference position (origin position) of the crosshead 7. It is also possible to set the position correction amount Δx in the direction in which the crosshead 7 retracts. Of course, in this case, the smaller the set mold clamping force, the larger the absolute value of the crosshead position correction amount Δx. Where to determine the reference position (origin position) is only a problem in data setting.

Further, in the case where a correlation can be easily found between the change in the set mold clamping force and the crosshead position correction amount required for aligning the toggle links 6 in a straight line. It is also possible to formulate this relationship and store it in the control program, and substitute the set mold clamping force into this calculation formula to automatically obtain the crosshead position correction amount according to the set mold clamping force. However, when such a configuration is applied, the file means shown in FIG. 5 is unnecessary.

As a method for detecting the position of the crosshead 7 in which the ternary link 3 and the binary link 5 are completely aligned in a straight line with no load or with the mold clamping force set, FIG. As shown, it is easiest to bridge the straight gauge 20 to one side of the nodes 15, 19 and 18 and check the gap between each node and the straight gauge 20. If all the nodes 15, 19 and 18 are in close contact with the straight gauge 20, it can be confirmed that the ternary link 3 and the binary link 5 are perfectly aligned. Of course, when the outer diameters of the respective nodes are different, the shape of the straight gauge 20 is adjusted accordingly, and all the nodes 1 with the ternary link 3 and the binary link 5 completely aligned.
5, 19 and 18 are configured to be in close contact with the straight gauge 20. Although the example of FIG. 2 shows the case where the outer diameters of all the nodes are the same, for example, when the outer diameter of the node 19 is smaller than that of the other nodes, the central portion of the straight gauge 20 in the longitudinal direction. In some cases, a protrusion or the like may be formed depending on the difference in outer diameter. Further, insulated contacts are provided at both ends of the straight gauge 20 and at positions corresponding to the respective nodes in the central portion in the longitudinal direction, and the indicator lamp is turned on only when these three contacts simultaneously contact the nodes 15, 19, and 18. By providing an electric circuit for making the buzzer sound or sounding the buzzer, the detection accuracy can be further improved as compared with the case of relying only on the visual measurement.

As described above, the position of the crosshead 7 in which the ternary link 3 and the binary link 5 are aligned on a straight line is obtained in advance according to the set mold clamping force before the mold clamping operation is started, and the position is determined at the stage of mold clamping. Although the embodiment has been described in which the ternary link 3 and the binary link 5 are aligned on a straight line when the mold clamping is completed by projecting the crosshead 7 to the position determined in advance, the final position of the crosshead 7 is not always necessary. The ternary link 3 and the binary link 5 can be aligned on a straight line when the mold clamping is completed without clarifying the target projecting position.

FIG. 3 shows an example of the embodiment. The mold clamping device 1 ′ shown in FIG. 3 is the mold clamping device 1 described in the above embodiment.
The structural difference is that the toggle link 6 is refracted at the portion of the node 19 that constitutes the pivotal connection between the ternary link 3 and the binary link 5 (the angle formed by the ternary link 3 and the binary link 5). Position detector 2 for detecting
1 is attached, and other components are exactly the same as those of the mold clamping device 1 described above.

The rotational position detector 21 can be composed of, for example, a potentiometer or an absolute encoder, and its output is connected to the numerical controller 100 via the interface 113. The value of the rotary position detector 21 when the ternary link 3 and the binary link 5 are aligned on a straight line is 180 in the case of the example of FIG.
°.

Also in this embodiment, the ternary link 3 is used with the mold clamping reaction force not acting on the toggle link 6 at all.
This is the same as the above-described embodiment in that the position of the crosshead 7 when the and the binary link 5 are completely aligned on a straight line is stored in the nonvolatile memory 114 as the reference position (origin position) of the moving platen 4. . Thus, if the position of the crosshead 7 when the ternary link 3 and the binary link 5 are aligned on a straight line with the mold clamping reaction force being zero is set as a reference position (origin position), a value larger than zero can be obtained. When the crosshead 7 is projected to the reference position (origin position) by setting the mold clamping force and adjusting the mold thickness and setting the mold pressure, due to the influence of the frictional resistance f2 around the node 15 described above. Always, toggle link 6 is shown in Figure 1.
Refraction as shown in (b) will occur. Of course, if the set mold clamping force is small, the refraction of the toggle link 6 may be almost equal to zero, but at least the position of the crosshead 7 will not go too far.

Therefore, in this embodiment, first, in the first stage of mold clamping, the crosshead 7 is projected from the set mold opening completion position to the above-mentioned reference position (origin position).
However, in reality, since the frictional resistance f2 is acting around the node 15, the ternary link 3 does not rotate sufficiently in some cases, and the toggle link 6 is not bent as shown in FIG. 1 (b). It may occur.

Therefore, in the present embodiment, after the crosshead 7 is projected to the reference position (origin position) as described above, the rotary position detector 21 and the ternary link 3 and the binary link are connected via the interface 113. The value of the angle formed with the link 5 is immediately read, and until the value reaches, for example, 180 ° described above, the mold clamping servomotor M1 is continuously driven to cause the crosshead 7 to project, and the ternary link 3 and the binary The links 5 are aligned on a straight line to complete the mold clamping state as shown in FIG. 1 (c).

With the crosshead 7 projected to the reference position (origin position), the ternary link 3 and the binary link 5 can be aligned on a straight line based on the angle value read from the rotational position detector 21. A required crosshead position correction amount (Δx in FIG. 1C) is obtained by calculation, and the obtained crosshead position correction amount is used as a movement command to further project the crosshead 7 from the reference position (origin position). Alternatively, after the crosshead 7 is projected to the reference position (origin position), the output from the rotational position detector 21 is sequentially detected, and feedback control is performed until the value reaches 180 °. The ternary link 3 and the binary link 5 may be aligned on a straight line by feeding the cross head 7.

Of course, when the crosshead position correction amount Δx is to be calculated based on the detection value of the rotational position detector 21 when the crosshead 7 is projected to the reference position (origin position), the rotational position detector 21 is operated. It is necessary to store a function indicating the correlation between the detected value and the crosshead position correction amount Δx in the numerical controller 100 in advance, but in reality, the detected value of the rotational position detector 21 (more strictly speaking, 180 °
Since there is a one-to-one correspondence between the set mold clamping force F and the set mold clamping force F, as a result, the relationship between the detection value of the rotational position detector 21 and the crosshead position correction amount Δx is the set mold clamping force F. It will correspond one-on-one as a mediation. That is, if a data file equivalent to that shown in FIG. 5 is created by using the range of detected values of the rotational position detector 21 instead of the set mold clamping force range, the crosshead 7 projects to the reference position (origin position). At this time, the crosshead position correction amount Δx can be obtained based on the detection value of the rotational position detector 21, and the crosshead position correction amount Δ is further increased from the reference position (origin position) of the crosshead 7.
By protruding by x, the ternary link 3 and the binary link 5 can be aligned on a straight line.

Each node portion 15, 1 of the toggle link 6
In the case where the greasing condition such as 9, 18 changes, the frictional resistance f2 around the node 15 fluctuates, so the mold clamping is performed with the same set mold clamping force and the crosshead 7 is moved to the reference position (origin position). Even if it is projected to (), the angle formed by the ternary link 3 and the binary link 5 may change. In such a case, in the embodiment in which the crosshead position correction amount Δx is obtained only based on the set mold clamping force, it is guaranteed that the ternary link 3 and the binary link 5 are necessarily aligned in a straight line to complete the mold clamping. However, the ternary link 3 and the binary link 5 are connected to each other by sequentially detecting the output from the rotational position detector 21 and feeding the crosshead 7 by feedback control until the value reaches 180 °. According to the above-described embodiment in which they are arranged in a straight line, the ternary must be used in response to not only the magnitude of the set mold clamping force but also the change in the greasing state of each node portion 15, 19, 18, etc. There is an advantage that the mold clamping can be completed in a state where the link 3 and the binary link 5 are aligned in a straight line.

Although the example in which the toggle mechanism is driven by the servo motor has been shown in the above-described embodiment, the present invention can be applied to a hydraulic toggle type mold clamping device driven by a hydraulic ram or the like.

[0061]

According to the present invention, by changing the projection completion position of the crosshead in accordance with the set mold clamping force, the posture of the toggle link at the time of mold clamping is always kept in a straight line so that all the mold clamping reaction force is maintained. Since it is designed to be supported by the toggle link itself along its axis, throughout the entire mold clamping period,
Neither mold clamping reaction force nor resin reaction force acts as a force that changes the posture of the toggle link. Therefore, it is not necessary to operate the drive source of the mold clamping device to maintain the mold clamping state no matter how large the set mold clamping force is, and it is possible to greatly save the energy consumption of the drive source during the mold clamping period. it can.

If the set mold clamping force is changed, the projection completion position of the crosshead is automatically adjusted so that the posture of the toggle link during the mold clamping is automatically adjusted accordingly. It is possible to always obtain the effect of saving the energy consumption of the drive source regardless of the change of the mold clamping force.

Further, since the toggle links are always aligned on a straight line when the mold clamping is completed, the actual separation distance between the rear platen and the moving platen at the completion of the mold clamping is set as the mold clamping force (calculation of the rear platen position). Since it exactly matches the eigenvalue of the separation distance used for the case, the problem of insufficient tie bar extension due to the insufficient separation distance between the rear platen and the moving platen was solved, and the mold clamping force as set was accurately reproduced. And can be maintained.

Further, a rotational position detector for detecting the refraction state of the toggle link is mounted to detect the refraction state of the toggle link, and the crosshead is projected until the toggle links are aligned to perform the mold clamping operation. According to this, each effect can be semipermanently obtained without being affected by aging changes such as changes in frictional resistance caused by changes in the greasing state of the node portion of the toggle link.

[Brief description of drawings]

FIG. 1 is a general configuration example of a toggle type mold clamping device, and
It is a partial side view which showed the operation principle of this invention.

FIG. 2 is an explanatory diagram showing an outline of a processing operation for obtaining a crosshead position correction amount according to the magnitude of a set mold clamping force.

FIG. 3 is a partial side view showing a toggle type mold clamping device to which a rotational position detector is attached.

FIG. 4 is a block diagram showing a main part of a control device for driving and controlling a toggle type mold clamping device and an injection molding machine main body.

FIG. 5 is a conceptual diagram showing a configuration of file means for storing a crosshead position correction amount corresponding to a set mold clamping force.

[Explanation of symbols]

 1 Toggle type clamping device 2 Rear platen 3 Turner link 4 Moving platen 5 Binary link 6 Toggle link 7 Crosshead 8 Crosshead link 9 Ball screw 10 Tie bar 11 Stationary platen 12a Movable side mold 12b Fixed side mold 13 Screw part 14 Tie bar Nut 15 node 16 pin 17 bush 18 node 19 node 20 straight gauge 21 rotational position detector

Claims (2)

[Claims] 1. In a toggle type mold clamping device, in order to align the toggle links in a straight line against a mold clamping reaction force according to a mold clamping force and a crosshead reference position where the toggle links are aligned in a straight line. And the crosshead position correction amount of the crosshead position correction amount are stored in advance, and a crosshead position correction amount corresponding to the set mold clamping force is added to the crosshead reference position according to the set mold clamping force to obtain a crosshead projection completion position. A method for adjusting a link posture of a toggle type mold clamping device, characterized in that a mold clamping operation is performed. 2. The toggle type mold clamping device is provided with a rotary position detector for detecting a refraction state of the toggle link, and at the time of mold clamping, a crosshead reference position where the toggle links are aligned in a straight line under a preset no-load condition. After projecting the crosshead until, the rotational position detector detects the refraction state of the toggle link, and the crosshead is projected until the toggle links are aligned to perform the mold clamping operation. A characteristic method for adjusting the link posture of a toggle type mold clamping device.