JPH0788915A - Mold thickness quantity detector of injection molding machine - Google Patents

Abstract

PURPOSE:To provide the inexpensive mold thickness quantity detector capable of accurately detecting mold thickness quantity without requiring an exclusive expensive position detector for detecting mold thickness quantity. CONSTITUTION:When the mold thicknesses of a fixed mold and a movable mold are adjusted by a mold thickness adjusting motor, mold thickness quantities are arbitrarily preset by a teaching part 21. The mold thickness quantities are operated and calculated from the toggle position detected by a toggle position detector 17 and the movable platen position detected by a movable platen position detector 19 by a mold thickness quantity operation means 25 and a movable platen is moved by the mold thickness adjusting motor so as to become the mold thickness quantities.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a mold thickness in an injection molding machine.

[0002]

2. Description of the Related Art FIG. 3 is a schematic configuration diagram showing a mechanism of a mold clamping / mold thickness adjusting section of a general vertical injection molding machine.

The mold clamping / mold thickness adjusting section of the vertical injection molding machine has a fixed platen 2 for mounting a fixed mold 1a, and a toggle mechanism 3 is arranged below the fixed platen 2. There is. The toggle mechanism 3 includes a pair of link rods 5 each having an upper end rotatably supported by a fixed platen 2 and a joint 4 in the center, and a ball screw 6 screwed into each joint 4 of the pair of link rods 5. It is composed by. The lower ends of the pair of link rods 5 are rotatably connected to a toggle receiving plate 7, and a tie bar is provided in a hole 7a formed in the toggle receiving plate 7 and a hole 2a formed in the fixed platen 2. 8 is inserted.

Further, a movable platen 9 is fixed to the upper end of the tie bar 8, and a movable mold 1b is fixed below the movable platen 9 and at a position facing the fixed mold 1a. Further, the lower end of each tie bar 8 is threaded, and these threaded portions 8a have a mold thickness adjusting nut 1
0 is screwed together. Then, these mold thickness adjusting nuts 1
A chain 11 is meshed with 0, and the chain 11 is rotated by a mold thickness adjusting motor 12.
Therefore, by rotating the chain 11, the mold thickness adjusting nut 10
Is rotated and the tie bar 8 is moved up and down, so that the movable mold 1b is moved up and down integrally with the movable platen 9.

On the other hand, a pulley 13 is fixed to one end of the ball screw 6, and a synchro belt 16 wound around a pulley 15 fixed to the shaft of a toggle drive motor 14 is wound around the pulley 13. Has been done. Further, the toggle drive motor 14 is mechanically connected to a toggle position detector 17 that detects the position of the toggle mechanism 3 by detecting its rotational position.

A rack 18 is fixed to the tie bar 8. A movable platen position detector 19 for detecting the position of the movable platen 9 by contacting the rack 18 and detecting the position of the tie bar 8 is fixed platen. It is fixed at 2.

Therefore, the toggle mechanism 3 expands and contracts by the rotation of the toggle drive motor 14 and the chain 11 rotates by the rotation of the mold thickness adjusting motor 12, and the mold thickness adjusting nut 10
Rotates, the tie bar 8 moves up and down, and the movable platen 9 moves up and down integrally with the tie bar 8. As a result, the movable mold 1b moves to the closed position or the open position separated from the fixed mold 1a. At this time, the toggle position detector 17 detects the position of the toggle mechanism 3 by detecting the rotation of the toggle drive motor 14, and the movable platen position detector 19 detects the position of the movable platen 9 by the position of the rack 18. To do. When the mold thickness adjusting motor 12 adjusts the mold thickness of the fixed mold 1a and the movable mold 1b, only the movable platen position detector 19 detects the position of the movable platen 9.

However, since the raising and lowering of the movable platen 9 by the toggle mechanism 3 and the raising and lowering of the movable platen 9 by the die thickness adjusting motor 12 may be performed separately, the toggle position and the movable platen position do not correspond, and In order to adjust the thickness, a mold thickness detecting device for an injection molding machine is generally provided with a position detector 20 for detecting the mold thickness by directly detecting the rotation of the mold thickness adjusting nut 10 as shown in FIG. It has become.

As shown in FIG. 5, this die thickness detecting device has a teaching section 21 for setting an origin offset for determining the zero point of the die thickness in advance. The teaching section 21 has an origin offset. A register 22 for storing is connected.
Further, the register 22 and the position detector 20 are connected to a subtractor 23 that subtracts the origin offset from the value detected by the position detector 20, and the subtractor 23 displays a die thickness amount. The part 24 is connected.

Therefore, when the die thickness of the fixed die 1a and the movable die 1b is adjusted by the die thickness adjusting motor 12, the position detector 20 directly detects the rotation of the die thickness adjusting nut 10 to determine the die thickness amount. Is detected, and the value obtained by subtracting the origin offset from the output of the position detector 20 by the subtractor 23 is displayed on the display unit 24 as the correct mold thickness amount.

[0011]

Since the conventional mold thickness detecting device for the injection molding machine is constructed as described above, an exclusive expensive position detector 20 for detecting the mold thickness is required. Therefore, there is a problem that the cost is increased.

The present invention has been made in order to solve the above problems, and can accurately detect the mold thickness without the need for an expensive position detector dedicated for detecting the mold thickness. It is an object of the present invention to provide an inexpensive mold thickness detection device for an injection molding machine.

[0013]

In order to achieve the above-mentioned object, a mold thickness detecting device of an injection molding machine according to the present invention comprises a mold thickness setting means capable of arbitrarily setting a mold thickness in advance, and the mold. There is a die thickness amount calculating means for calculating the die thickness amount from the positional relationship between the toggle position and the movable platen position by the movement of the movable platen by the thickness adjusting motor.

[0014]

According to the die thickness detection method of the present invention, the positional relationship between the toggle position detected by the toggle position detector and the movable platen position detected by the movable platen position detector stored in advance is determined by the die thickness adjusting operation. Utilizing the shift,
The die thickness can be calculated by calculating from the deviation amount.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram showing the structure of a control unit of a mold thickness detecting device of an injection molding machine according to the present invention.

The control unit of the mold thickness detecting device sets the toggle position detector 17, the movable platen position detector 19, the origin offset for determining the zero point of the mold thickness, and the mold thickness arbitrarily in advance. It has a teaching section 21 as a die thickness setting means for setting. Further, the toggle position detector 17, the movable platen position detector 19 and the teaching section 21 are provided with a die thickness amount from the toggle position detected by the toggle position detector 17 and the movable platen position detected by the movable platen position detector 19. A die thickness amount calculating means 25 which is calculated and obtained is connected, and a display part 24 is connected to the die thickness amount calculating means 25.

The mold thickness calculating means 25 has three registers 26, 27 and 28 and four subtractors 29 and 30,
31, 32 and toggle-movable platen position conversion unit 33
And a multiplexer 34. Further, the register 26 stores the origin offset (ofw) that determines the zero point of the mold thickness amount by the setting operation of the teaching unit 21, and the register 28 stores the mold thickness arbitrarily set in advance. The quantity (d) is stored, and the output value (ofa) of the subtracter 31 is stored in the register 27.

Next, the toggle-movable platen position conversion unit 3
The function of No. 3 will be described. FIG. 2 is a diagram illustrating the positional relationship between the toggle and the movable platen. ew indicates the value of the toggle position detector, and ea indicates the value of the movable platen position detector. The toggle-movable platen position conversion within the broken line in the figure shows the relationship of the moving amount of the movable platen to the moving amount of the toggle. How much the movable platen moves when the toggle moves from the toggle position origin. Can be obtained by calculation from the respective dimensions of the toggle mechanism, and is expressed as a = f (w) here. ofw is a toggle position origin offset, and is set so that the toggle position w becomes zero when the toggle mechanism is in the most extended state.
Further, d is a die thickness and sets a distance between the movable platen and the fixed platen when the toggle position w is zero. If the current toggle position is Pew and the movable platen position is Pea, the movable platen position detector origin offset ofa is set by the following formula by setting the toggle position detector origin offset ofww and the die thickness d. Is determined, and as a result, the positional relationship between the toggle and the movable platen is determined.

Movable platen position detector origin offset:
ofa = Pea-f (Pew-ofw) -d Next, a method of calculating the mold thickness amount when the mold thickness adjusting operation is performed will be described. The mold thickness adjusting nut is rotated by driving the mold thickness adjusting motor, and the movable platen is moved by vertically moving the tie bar. In this case, since the toggle side does not move, there is a deviation in the positional relationship between the toggle and the movable platen obtained earlier. Therefore, the die thickness amount d should be updated by the following formula to maintain the positional relationship between the toggle and the movable platen. Thus, the die thickness amount d can always be detected by showing an accurate value.

Mold thickness: d = Pea'-f (Pew-ofw) -ofa (Pea 'is the movable platen position changed by the mold thickness adjusting operation)

[0021]

According to the present invention, an inexpensive die thickness detection function can be provided by enabling accurate die thickness detection without requiring a dedicated detector for directly detecting the die thickness.

[0022]

[Brief description of drawings]

[0023]

FIG. 1 is a block diagram of a mold thickness detection display function embodying the present invention.

[0024]

FIG. 2 is a diagram illustrating a relationship between a toggle position and a movable platen position.

[0025]

FIG. 3 is a mechanism diagram of a mold clamping and mold thickness adjusting unit of a vertical injection molding machine.

[0026]

FIG. 4 is a mechanism diagram of conventional die thickness detection.

[0027]

FIG. 5 is a circuit diagram showing a configuration of a control unit of a conventional mold thickness detection device of an injection molding machine.

[0028]

[Explanation of symbols]

 1a Fixed mold 1b Moving mold 2 Fixed platen 3 Toggle mechanism 8 Tie bar 9 Movable platen 10 Mold thickness adjusting nut 12 Mold thickness adjusting motor 14 Toggle drive motor 17 Toggle position detector

Claims (1)

[Claims] 1. A mold clamping servomotor for driving a movable platen for opening and closing a mold via a toggle mechanism, and a toggle position detecting means for detecting a toggle position by a position detector attached to the mold clamping servomotor. A movable platen position detecting means for detecting the movable platen position by a movable platen position detector mechanically coupled to the movable platen;
In a mold thickness detection device of an injection molding machine equipped with a mold thickness adjusting motor for moving a movable platen for mold thickness adjustment,
A mold thickness setting means capable of arbitrarily setting a mold thickness in advance, and a mold thickness calculated by calculating the mold thickness from the positional relationship between the toggle position and the movable platen position by moving the movable platen by the mold thickness adjusting motor. An apparatus for detecting a mold thickness of an injection molding machine, which has a calculating means.