JPS629925A - Nozzle touching mechanism in injection molding machine - Google Patents

Abstract

PURPOSE:To enable to select amounting position freely by reducing a matter making a stationary board bend, by a method wherein the title mechanism is constituted of a pulley transmitting a rotation of a motor to a ball screw and a timing belt and a transmission mechanism is stuck to the stationary board to which a mold is fitted. CONSTITUTION:When a motor 8 is made to rotate positively, a first rotary shaft 21 is rotated, a second rotary shaft 26 is made to rotate positively through a pulley 23, timing belt 24 and pulley 25 and a ball nut 10 screwing with a ball screw 9 is made to advance. A nozzle 3 presses the mold and force making a stationary platen 4 bend in a clockwise direction centering around a sticking point with a base 15 is applied to the stationary board 4. As the motor 8 and a transmission mechanism 7 are stuck to a stationary board 4, the force wherein the nozzle 3 presses the mold, that is, force wherein a spring 13 presses an extruder base 5 is transmitted to the transmission mechanism 7 through a second plate 12 and the rotary shaft 26 as reaction force of the above force and the force going to make the stationary board 4 bend in a counterclockwise direction is applied to the stationary board 4. Therefore, as the force, which is in the opposite direction to that of the force form the nozzle 3 and is about identical with the same, is applied to the stationary board 4, bending amount of the stationary board 4 becomes small.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a nozzle touch mechanism that brings a nozzle into pressure contact with a mold of an injection molding machine.

BACKGROUND OF THE INVENTION The nozzle touch mechanism in conventional injection molding machines uses a hydraulic cylinder to press the nozzle against the mold using hydraulic pressure. It is necessary to press the nozzle against the mold at a constant pressure, but when hydraulic pressure is used, a constant pressure is always maintained by switching valves. However, when trying to drive the nozzle touch mechanism with a motor, it is necessary to maintain a constant pressure at all times, so it is necessary to keep a constant current flowing through the motor, or when cutting off the current to the motor and applying the brake. Once the motor shaft rotates for some reason, it is no longer held at a constant pressure. Therefore, the driving force of the motor is transmitted to the injection unit via the spring to press the nozzle against the mold, and even if some external force is applied to the injection unit, the spring absorbs that external force, and the nozzle is always pressed against the mold at a constant pressure. A press-holding method was developed (Japanese Patent Application No. 114433/1983, etc.).

Problems to be Solved by the Invention The present invention relates to a nozzle touch mechanism that transmits the driving force of the motor to the injection unit via a spring to press the nozzle against the mold. The driving force is used to drive a ball screw using a gear, and the ball nut that the ball screw engages with is moved in the axial direction to move the injection unit via a support spring and press the nozzle against the mold. Since gears are used, there are restrictions on the installation position of the motor, etc., and an optimal layout cannot be obtained.

In addition, because the nozzle presses against the mold, it causes the fixed plate to which the mold is fixed to bend around the fixed point where the fixed plate is fixed to the base (this also applies to conventional hydraulic systems). ). Therefore, the present invention aims to improve the above-mentioned drawbacks.

Means for Solving the Problems The present invention rotates a ball screw through a transmission mechanism by the rotation of a motor, moves a ball nut that is threaded with the ball screw, and moves the ball nut through a spring. In the nozzle touch mechanism that transmits power to the injection unit to press the nozzle into contact with the mold, the transmission mechanism includes a pulley and a timing bell 1 to transmit the rotation of the motor to the ball screw, and the transmission mechanism The above problem was solved by fixing the mold to a fixed plate on which the mold was attached.

The rotation of the operating motor is transmitted to the ball screw by the pulley and timing belt, the ball nut screwed into the ball screw moves in the axial direction of the ball screw, and the movement of the ball nut is transmitted to the injection unit via the spring. Then, press the nozzle into contact with the mold and release it. And the transmission m from the motor to the ball screw
'4PJ is fixed to the fixed platen on which the mold is attached, so the reaction force of the nozzle pressing the mold is transmitted to the fixed platen via the transmission mechanism, causing the fixed platen to flex. Moreover, since the transmission mechanism is based on the pulley and the timing bell 1, the installation position of the motor can be freely selected.

Embodiment FIG. 1 is a side view of an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1 with injection units 1 to 1 removed, and FIG.
The figure shows a detailed diagram of the transmission mechanism, 1 is an injection unit, 2 is a heating cylinder, 3 is a nozzle provided at the tip of the heating cylinder, 4 is a fixed plate to which a mold is attached, 5 is a rail 6
The injection unit 1 is fixed onto the extruder base which slides on the extruder base. 7
is a transmission mechanism fixed to the fixed platen 4, 8 is a motor, and 9 is a transmission mechanism fixed to the fixed platen 4;
10 is a ball screw, 10 is a ball nut 1 screwed onto the ball screw, 11 is a first plate fixed to the ball nut 10, 12 is a second plate, 13.
13 is a spring, 14, 14 is a shirt 1~. 15 is the base.

Next, the transmission mechanism 7 will be explained in detail with reference to FIG. A first bearing body 30 is fixed to the fixed platen 4, and a second bearing body 31 is fixed to the extension member 32 of the first bearing body 30 with bolts or the like.

A motor 8 is fixed to the second bearing body 31. Motor IIqII20 of motor 8 is connected to coupling member 22
The first rotating shaft 21 is rotatably fixed by a bearing B, and a pulley 23 is fixed to the first rotating shaft 21. Further, a second rotating shaft 26 is rotatably fixed to the first bearing body 30 through a bearing port, and a pulley 25 is fixed to the second rotating shaft 26. 24 cannot be connected to timing bell 1. As shown in FIGS. 1 and 2, a ball screw 9 is fixed to the second rotating body 26 at the other end. A ball nut 10 is attached to the ball screw 9.
are screwed together, a first plate 11 is fixed to the ball neck 1-1°, two shirts 1-14 and 14 are fixed to the first plate 11, and the shaft L/I,
A second plate 12 is fixed to the other end of 14.

The first plate 11 is in contact with the end of the extruder base 5, and the shaft 14.
17'l is provided at the end of the extruder base 5 (passing through a slotted hole 33), and the shaft 14.14 has a spring between the end of the extruder base 5 and the second plate 12. 13 are provided.

The ball screw 9 passes through the holes 34, 35, and 36 provided in the ends of the extruder bases 5 of the first plates 6-1 to 11 and the second plates 1 to 12, respectively. It protrudes to the left in Figure 2.

Note that 37 is a sensor fixed to the extruder base 5, which detects the first plate and detects when the nozzle 3 is properly pressed against the mold.

The operation of this embodiment having the above configuration will be described next.

First, in order to press the nozzle 3 against the mold, the motor 8 is driven and rotated in the forward direction, the first rotating shaft 21 rotates, and the second The rotating shaft 26 of is rotated in the forward direction. When the second rotating shaft 26 rotates forward, the ball screw 9 rotates forward, causing the ball screw 9 (~10) to move forward (to the right in FIGS. 1 and 2), and as a result, the ball The first plate 11 fixed to the nut 10 also moves forward, and the shaft 14゜1 fixed to the first plate 11 moves forward.
4 also moves forward, the second plate fixed to the shaft 14.14 also moves forward, and the second plate 14.
presses the spring 1'3.13, and the spring 13
．． The extruder base 5 slides on the rail 6 and advances the injection unit 1 fixed to the extruder base 5, causing the nozzle 3 to move forward. It comes into contact with the mold. Nozzle 3
Even if J contacts the mold, if the motor 8 is further driven, =[
Despite Kistrug Base 5 being stopped,
Ball nut 10. 1st. The second plates 11, 12 move forward and the second plate 12 causes the spring 13.
13 is compressed, and the reaction force due to this compression is transmitted to the extract 1 to the router base 5, and becomes a force that presses the nozzle 3 against the mold. Then, the sensor 37 detects the first plate, and the drive of the motor 8 is stopped based on this signal. That is, the sensor 37 causes the spring 13.1 to
3 is detected, and when the appropriate compression amount, that is, the appropriate pressing force is reached, the sensor 37 detects the first play 1-11 and stops the motor 8.

Next, in order to remove the nozzle 3 from the mold, the motor 8 is rotated in the opposite direction, and as described above, the first rotating shaft 21 and the
23, reverse the ball screw 9 through the timing bell l-24, pulley 25, and second rotation @26, and retract the ball nut 10 and the first play 1-11 (left in Figures 1 and 2). direction). Therefore, the first plate 1
1 presses the end of the extruder base 5, the extruder base 5 and the injection unit 1 are moved back, and the nozzle is removed from the mold B111.

As described above, in the present invention, since the nozzle 3 is pressed against the mold by the compression force of the spring 13.13,
Even if some external force is applied, it is instantly absorbed by the springs 13, 13 and then restored, so that a constant pressing force of the nozzle against the mold is always obtained.

In addition, since the nozzle 3 presses the mold, as shown in FIG. Since the motor 8 and the transmission mechanism 7, which are the driving source for pressing the nozzle 3 against the mold, are fixed to the fixed plate 4, the force of the nozzle 3 pressing against the mold, that is, the spring 13,
The force with which 13 presses Extract 1 to Rogue Base 5 is the reaction force to second play 1 to 12 and shirt 1 14.14
, is transmitted to the transmission mechanism 7 via the first plate 11, the ball nut 10, the ball screw 9, and the rotating shaft 26,
A force is applied to the fixed platen 4 and tends to bend the fixed platen 4 in the counter-chronological direction. Therefore, the force from the nozzle 3 and the nuclear force from the transmission mechanism 7, which are opposite in direction and have approximately the same magnitude, are applied to the fixed platen 4, so the force that bends the fixed platen 4 becomes smaller, and the deflection of the fixed platen 4 decreases. becomes smaller.

In the above embodiment, the spring is compressed and the nozzle is pressed against the mold by the reaction force caused by the compression, but the spring may be expanded and the nozzle pressed against the mold by the tensile force generated at that time. Further, in the above embodiment, the sensor 37 detects the amount of compression of the spring, that is, the pressing force of the nozzle against the mold.
Instead, the appropriate pressing force may be detected based on the drive current value of the motor, that is, when the nozzle comes into contact with the mold and the pressure nozzle J increases, the motor drive current increases. .

Furthermore, the motor may be a servo motor, and a position detector of the servo motor may detect the point of appropriate pressing force.

Effects of the Invention As described above, the present invention uses a timing belt to transmit the driving force from the motor to the ball screw that moves the injection unit, so the installation position of the motor is not limited and can be placed arbitrarily, and This fixes the transmission mechanism to the stationary platen to which the mold is fixed, so the force from the nozzle that is applied to the stationary platen is applied to the stationary platen as a reaction force through the transmission mechanism, reducing the amount of deflection of the stationary platen. , a molded product with higher precision can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view of an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1 with the removal unit removed, and FIG. 3 is a detailed view of the transmission mechanism. 1...q1 output unit, 2...heating shilling, 3...
... Nozzle, 4... Fixed plate, 5... Extruder base, 6... Rail, 7... Transmission mechanism, 8...
Motor, 9... Ball screw, 10... Ball nut, 11... To first play 1, 12... Second
To play 1, 13...Spring, 14...Shaft, 15...Base, 21...First rotating shaft, 2
3.251.・Pulley, 24...timing belt,
26...Second rotating shaft, 37...Sensor.

Claims (1)

[Claims] The rotation of the motor rotates a ball screw via a transmission mechanism, moves a ball nut that is threaded onto the ball screw, and transmits the movement of the ball nut to the injection unit via a spring, bringing the nozzle into contact with the mold. In the nozzle touch mechanism configured to press, the transmission mechanism is composed of a pulley and a timing belt that transmit the rotation of the motor to the ball screw, and the transmission mechanism is fixed to a fixed plate to which the mold is attached. Features a nozzle touch mechanism in injection molding machines.