JPH074816B2 - Position adjustment method of mold clamping device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the position of a mold clamping device in an injection molding machine for adjusting the position of a pressure receiving plate that supports a mold clamping mechanism.

[0002]

2. Description of the Related Art Generally, a mold clamping device of an injection molding machine applies a predetermined mold clamping force to a mold. In the case of the toggle type mold clamping device, the mold clamping force is proportional to the extension of the tie bar during mold clamping due to the characteristics of the toggle mechanism (mold clamping mechanism). For this reason, in the toggle type mold clamping device, after mounting the mold, the toggle mechanism is clamped with the toggle mechanism expanded to the maximum extent, and at this time, the tie bar is stretched on the tie bar so that the elongation becomes the set mold clamping force. The position of the entire toggle mechanism (pressure receiving plate) is adjusted according to the mold thickness, and such a method for setting the mold clamping force is disclosed in, for example, Japanese Patent Publication No. Sho 61-35924 and Japanese Patent Laid-Open No. 1-275001.
It is known from Japanese Patent Publication No. 6 and the like.

Further, in this type of mold clamping device, a pressure receiving plate is used in response to a subtle change in the mold thickness which occurs when the mold temperature or the like changes, or when it is desired to subtly change the mold clamping force which is a molding condition. It is necessary to slightly move the position of and to finely adjust the position. In this case, a position sensor that can detect the position of the pressure receiving plate is provided, and when adjusting the position, the drive motor is used to move the pressure receiving plate, and the position sensor detects the position of the pressure receiving plate. When the set value is reached, the drive motor is stopped and thereby the position adjustment for moving the pressure receiving plate to the target position is performed.

[0004]

However, the above-mentioned conventional position adjusting method has the following problems.

That is, as a drive motor for moving the pressure receiving plate, a general-purpose motor such as a geared motor with a brake using an inexpensive induction motor is usually used in consideration of cost (Japanese Patent Publication No. 61- (See Japanese Patent Publication No. 11174). Therefore, when the drive motor is stopped, overrun occurs due to coasting due to inertia, and overrun is caused by the difference in commercial power supply frequency and the rotation speed of the drive motor depending on the motor operation timing (startup or constant speed). The run size varies.

Further, as shown in FIG. 3, the pressure receiving plate 5 is usually used.
0 is slidably loaded on the tie bar 51, and
The mold thickness adjusting nut 5 is attached to the screw portion 52 formed on the tie bar 51.
3, the mold thickness adjusting nut 53 and the pressure receiving plate 50 are engaged by the engaging portion 54. With this mechanism, the pressure receiving plate 50 can be moved along the tie bar 51 by rotating the die thickness adjusting nut 53 by the drive motor, but a gap that causes backlash between the tie bar 51 and the pressure receiving plate 50. There are S1, S2, etc., which causes an error.

For this reason, at the time of position adjustment, even if the drive motor is stopped after being operated, the stop position of the drive motor becomes extremely unstable, and accurate position adjustment cannot be performed. There was a point that it lacked accuracy.

The present invention has solved the problems existing in the prior art as described above. Even when a general-purpose motor is used and adjustment adjustment is performed, the position of the pressure receiving plate is always accurately and accurately maintained. An object of the present invention is to provide a method for adjusting the position of a mold clamping device that can be easily adjusted.

[0009]

A position adjusting method for a mold clamping device according to the present invention is configured such that a drive motor, in particular, a general-purpose motor 2 is used to move a pressure receiving plate 4 that supports a mold clamping mechanism 3 and a position sensor 5 is used. When the position of the pressure receiving plate 4 is detected and the detected value Dd reaches a preset setting value Ds, the general-purpose motor 2 is stopped and the pressure receiving plate 4 is adjusted to the target position Ps. Ps is a correction value β that cancels the movement distance of the pressure receiving platen 4 that is overrun by inertia when the general-purpose motor 2 is stopped during rotation at a stable speed.
The setting value Ds corresponding to the target position Ps is set by correcting the pressure receiving plate 4 at the time of position adjustment, and the pressure receiving plate 4 is moved after the pressure receiving plate 4 is separated from the target position Ps by a predetermined distance α or more. Is characterized by. The predetermined distance α in this case is at least the moving distance of the pressure receiving platen 4 from the start of the general-purpose motor 2 until reaching the stable speed, and the pressure receiving platen 4 overruns due to inertia when stopped while rotating at the stable speed. While setting to the distance that added the moving distance,
It is set in the backward direction of the pressure receiving plate 4. Further, the deviation value γ of the detected value Dd with respect to the target position Ps is obtained, and if the deviation value γ is out of the preset allowable range, the correction value β is corrected by the deviation value γ. Repeat until you enter.

[0010]

According to the position adjusting method for the mold clamping device according to the present invention, when the pressure receiving platen 4 is moved by the general purpose motor 2, the pressure receiving platen 4 is previously activated from the target position Ps by at least the general purpose motor 2. Move in the backward direction over a predetermined distance α, which is the sum of the moving distance of the pressure receiving platen 4 until reaching the stable speed and the moving distance that the pressure receiving platen 4 overruns due to inertia when stopped while rotating at the stable speed. After that, since the pressure receiving plate 4 is moved forward, the general-purpose motor 2 is always in a stable constant speed state when the general-purpose motor 2 is stopped, even if a slight adjustment is performed.
It does not stop from the accelerating state as when starting the general-purpose motor 2. Therefore, even if the general-purpose motor 2 coasts after stopping and overruns, the moving distance of the pressure receiving plate 4 due to coasting is always constant. Moreover, at this time, if the direction of the predetermined distance α is set as the retracting direction of the pressure receiving platen 4, the adjustment direction is always the same direction, and the influence of backlash is prevented.

On the other hand, the target position Ps is corrected in advance with a correction value β that cancels out the moving distance of the pressure receiving platen 4 which is overrun by inertia when the general-purpose motor 2 is stopped while rotating at a stable speed. Thus, since the set value Ds is set, the position sensor 5 detects the position of the pressure receiving platen 4 at the time of position adjustment, and when the detected value Dd obtained therefrom reaches the preset set value Ds, the general purpose If the motor 2 is stopped, the pressure receiving platen 4 will move to the regular target position P.
s is adjusted with high accuracy and high reproducibility.

Further, a deviation value γ of the detected value Dd with respect to the target position Ps is obtained, and if the deviation value γ is out of the allowable range, the correction value β is corrected by the deviation value γ. This correction is the deviation value γ
Is repeatedly performed until the value falls within the allowable range, even if, for example, the rotation speed of the general-purpose motor 2 changes due to the difference in commercial power source frequency caused by the place of use and the correction value β no longer matches, The correction value β can be corrected so that accurate position adjustment is always performed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, a mold clamping device 1 capable of carrying out the method of the present invention.
The overall configuration of will be described with reference to FIG.

Reference numeral 10 denotes a mold clamping device bed, on one side of which a fixed plate 11 is erected and installed. The fixed die 12s of the die 12 is attached to the substantially central portion of the fixed board 11, and one end of each tie bar 13 is fixed to the four corners so as to be parallel to the horizontal direction. An injection device (not shown) is installed so as to face the stationary platen 11, and constitutes an injection molding machine together with the main mold clamping device 1. Further, screw parts 14 are provided on the other end side of the tie bars 13. On the other hand, a movable platen 15 is slidably mounted on the tie bars 13 ... And a movable die 12t is attached to the movable platen 15 substantially at the center thereof. On the other hand, a pressure receiving plate (toggle receiving plate) 4 is slidably mounted on the other side of the tie bars 13 ... And a toggle mechanism 3T constituting a mold clamping mechanism 3 is installed between the pressure receiving plate 4 and the movable plate 15. The toggle mechanism 3T is a front toggle link 3f connecting the pressure receiving plate 4 and the movable plate 15,
3f and rear toggle links 3r, 3r are provided on the upper and lower sides, and the rear toggle links 3r, 3r are connected to the central crosshead 16 via the intermediate toggle links 3m, 3m, and the inside of the crosshead 16 has a ball nut. 17 and is screwed into the ball screw 18. The rear end side of the ball screw 18 is rotatably attached to the pressure receiving plate 4 and is rotated by a servo motor 21 via a rotation transmission mechanism 20.

Further, a mold thickness adjusting nut 22 is screwed into the thread portion 14 of the tie bar 13. The mold thickness adjusting nut 22 is rotatably engaged with the pressure receiving plate 4, and is rotated by a geared motor 2g with brake (general-purpose motor 2) via a rotation transmission mechanism 23. The geared motor 2g is attached to the pressure receiving plate 4.

A pressure receiving plate 4 is provided on the mold clamping device bed 10 side.
The position sensor 5 for detecting the position of is attached. The position sensor 5 detects the absolute position of the pressure receiving plate 4 on the tie bar 13 as 0.
It can be detected in units of 01 mm, and for example, a digital electric scale or the like can be used.

On the other hand, 24 is a central controller. The central controller 24 contains a microcomputer,
It has a control function of the entire injection molding machine including the mold clamping device 1 and the injection device. The central controller 24 is the ROM 2 storing a control program for executing the position adjusting method according to the present invention.
5, RAM 26 for temporary storage of data and arithmetic processing,
Starting with the non-volatile memory 27 that stores various setting values,
A display 28, an input device 29, etc. are provided.

Further, the central controller 24 is connected to the servo motor 21 via the servo motor control section 30, and is also connected to an encoder (rotational position detector) 31 built in the servo motor 21. Servo motor control unit 30
Is the servomotor 21 according to a command from the central controller 24.
Is driven to control the speed and position of the crosshead 16, and torque limit control is performed on the output torque of the servomotor 21. As a result, the crosshead 16
The forward and backward forces of the are controlled. The encoder 31 is an absolute type, and detects the position and speed of the crosshead 16 and applies the detected position and speed to the central controller 24. In this case, the toggle head 3T spreads the cross head 16 to the maximum extent.
The most advanced position (mold clamping position) of 0 becomes zero (0), and the direction in which the toggle mechanism 3T contracts (mold opening direction) becomes plus (+), and the position control of the movable platen 15 is performed based on this. Further, the geared motor 2g is connected to the central controller 24 via the geared motor controller 32.
The geared motor control unit 32 operates the geared motor 2g in response to a command from the central controller 24 to control the movement or holding of the pressure receiving plate 4.

Therefore, the setting of the mold clamping force in the mold clamping device 1 is performed by moving the entire toggle mechanism (pressure receiving plate 4) backward by the geared motor 2g, and at the same time the servo motor 21 is set.
When the crosshead 16 reaches the mold clamping force setting position while maintaining the mold touched state by advancing the crosshead 16 of the toggle mechanism 3T from the position before the mold clamping force setting position in the direction of expanding the toggle mechanism 3T. It suffices to stop the geared motor 2g and the servo motor 21 and set the position of the pressure receiving plate 4 according to the mold thickness.

Next, the position adjusting method according to the present invention will be described with reference to the flowchart shown in FIG.

Such position adjustment is performed, for example, when fine adjustment is performed by further slightly moving the pressure receiving platen 4, which is set in accordance with the setting of the mold clamping force.

First, the target position Ps to be adjusted with respect to the pressure receiving platen 4 is input automatically or manually. As a result, the adjustment command is issued, and the central controller 24 detects the current detection value Dd of the pressure receiving platen 4 detected by the position sensor 5.
Then, it is determined whether it is in the state of Dd ≧ (Ps + α) (step 60). In this case, α is a predetermined distance, and after the geared motor 2g is started, the moving distance of the pressure receiving plate 4 required to reach the rated speed (stable speed) and the geared motor 2g during the rotation of the rated speed (stable speed). It corresponds to a distance obtained by adding a moving distance by which the pressure receiving platen 4 overruns when it is stopped, and is stored in the nonvolatile memory 27 in advance.

As a result, when Dd <(Ps + α), the geared motor 2g is once driven and Dd ≧ (Ps
The pressure receiving platen 4 is retracted in the direction away from the fixed platen 11 until the state becomes + α) (steps 61 and 62). As a result, the pressure receiving board 4 is separated from the target position Ps by a predetermined distance α or more.

Further, the central controller 24 reads the correction value β stored in the non-volatile memory 27 in advance and calculates the set value Ds from the input target position Ps. That is, the set value Ds corrected for the target position Ps by the correction value β is obtained, and the set value Ds is Ds = P.
It is set as s + β (step 63). in this case,
The correction value β corresponds to the moving distance that the pressure receiving platen 4 overruns due to inertia when the geared motor 2g is stopped while rotating at the rated speed (stable speed).

When the above setting is completed, the geared motor 2g is then driven in the opposite direction to move the pressure receiving plate 4 forward (step 64). Then, the position sensor 5 detects the position of the pressure receiving platen 4, and the detected value D
d is monitored, and the detected value Dd matches the set value Ds, that is, D
When d = Ds, the operation of the geared motor 2g is stopped (steps 65 and 66). It should be noted that, when the pressure receiving platen 4 is moved, it is desirable to give a torque limit command to the servo motor 21 or turn it off so that the load on the geared motor 2g does not become large.

After the lapse of a predetermined time, the position sensor 5 detects the position of the pressure receiving platen 4 to obtain a detection value Ds.
The central controller 24 detects the detected value D for the target position Ps.
The deviation value γ of d is calculated (steps 67 and 68), whereby whether or not the deviation value γ falls within the preset allowable value M (allowable range), that is, the condition of | γ | ≦ M Or not. At this time, if | γ | ≦ M, the adjustment process is terminated (step 69).

However, when │γ│> M, the deviation value γ
(= ± γ) is added to the correction value β, and the newly obtained correction value β ± γ is updated and stored in the nonvolatile memory 27. As a result, the set value Ds is also automatically changed to Ds = Ps + (β ± γ) (step 70). Then, a new set value Ds
By doing, the position is adjusted again by the same procedure,
The deviation value γ of the detected value Dd with respect to the target position Ps is obtained, and the deviation value γ is repeated until it falls within the allowable range (allowable value M) (steps 63 to 69). An error may be displayed if the allowable range is not reached even after repeating a certain number of times.

Although the embodiments have been described in detail above, the present invention is not limited to such embodiments. For example, the drive motor is exemplified by a geared motor with a brake, but various general-purpose motors including various general-purpose motors having no position control function may be applied. Further, although the toggle type mold clamping device is exemplified, a crank type mold clamping device may be used. In addition, the detailed configuration, method, and the like can be arbitrarily changed without departing from the scope of the present invention.

[0030]

As described above, in the position adjusting method for the mold clamping device according to the present invention, the pressure receiving plate that supports the mold clamping mechanism is moved by the drive motor, and the position of the pressure receiving plate is detected and detected by the position sensor. If the value reaches the preset value, when the drive motor is stopped and the pressure platen is adjusted to the target position, when the target position is stopped in advance while the drive motor is rotating at a stable speed. By setting the set value corresponding to the target position by correcting the moving distance that the pressure receiving plate overruns due to inertia, the setting value corresponding to the target position is set, and the position of the pressure receiving plate is moved backward from the target position by a predetermined distance or more during position adjustment. After moving it, the pressure platen was moved forward, so a drive motor such as a general-purpose motor was used.
Moreover, even when the adjustment is performed, the remarkable effect that the position of the pressure receiving plate can always be accurately and easily adjusted is obtained.

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure of a position adjusting method according to the present invention,

FIG. 2 is a configuration diagram of a mold clamping device capable of performing the same position adjusting method,

FIG. 3 is an explanatory view of backlash in the mold clamping device,

[Explanation of symbols]

 1 mold clamping device 2 general-purpose motor (drive motor) 3 mold clamping mechanism 4 pressure receiving plate 5 position sensor Dd detection value Ds set value Ps target position α predetermined distance β correction value γ deviation value

Claims (3)

[Claims] 1. A detection value (D) is obtained by moving a pressure receiving plate (4) supporting a mold clamping mechanism (3) by a drive motor and detecting the position of the pressure receiving plate (4) by a position sensor (5).
When d) reaches a preset set value (Ds), the position adjusting method of the mold clamping device in which the drive motor is stopped and the pressure receiving plate (4) is adjusted to the target position (Ps),
By previously correcting the target position (Ps) with a correction value (β) that cancels the moving distance that the pressure receiving plate (4) overruns due to inertia when the drive motor is stopped while rotating at a stable speed, Set value (D) corresponding to the target position (Ps)
s) is set and the pressure receiving plate (4) is used when adjusting the position.
From the target position (Ps), at least when the pressure receiving plate (4) moves from the start of the drive motor until it reaches a stable speed, and when the pressure receiving plate (4) is stopped during the rotation of the stable speed, After moving in the backward direction for a predetermined distance (α) or more in which the moving distance for overrun is added, the pressure receiving plate (4)
When the pressure receiving plate (4) reaches the set value (Ds), the drive motor is stopped and the pressure receiving plate (4) is adjusted to the target position (Ps). Position adjustment method for tightening device. 2. A detection value (D) for a target position (Ps)
The deviation value (γ) of d) is obtained, and if the deviation value (γ) is out of a preset allowable range, the correction value (β) is corrected by the deviation value (γ). Position adjustment method of mold clamping device. 3. The position adjusting method for a mold clamping device according to claim 2, wherein the correction value (β) is repeatedly corrected until the deviation value (γ) falls within an allowable range.