JP2002052585A - Motor-operated injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive mechanism by a servo motor durable against a mold clamping pressure near a maximum mold clamping force. SOLUTION: A motor-operated injection molding machine 100 comprises a toggle mechanism 40 to press a movable die plate (not shown) to a fixed die plate. The machine 100 further comprises first and second mounting seats 32 provided at a tail stock 130, and two servo motors 80 mounted at the seats 31. The motors 80 drive two ball screws 60 via a belt 84. The machine also comprises a third mounting seat 132 prepared at the stock 130, and a third servo motor 180 mounted via a bracket 200 as needed. The motor 180 drives two ball screws 60 via a belt 184. In a state immediately before the maximum mold clamping force to become immediately before the toggle mechanism becomes a dead point, a maximum torque load is applied to the motor. The torque load is dispersively loaded by the three motors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electric injection molding machine for molding a synthetic resin or the like.

[0002]

2. Description of the Related Art FIG. 7 is a front view showing the entire structure of an electric injection molding machine which is the basis of the present invention, and FIG. 8 is a left side view. The electric injection molding machine generally indicated by reference numeral 1 has a fixed die plate 10 fixed on a bed (not shown),
The fixed die plate 10 has a fixed die 12 attached thereto. A movable die 22 is attached to the movable die plate 20 disposed opposite to the fixed die plate 10, and synthetic resin as a material is injection-molded when the movable die comes into contact with the fixed die.

[0003] The movable die plate 20 is provided with a toggle mechanism 40.
Through the tail stock 30. The tail stock 30 is a fixed die plate 1 with four tie bars 70.
Connected to 0. The four tie bars 70 pass through the movable die plate 20 and slidably support the movable die plate 20.

The toggle mechanism 40 has a toggle member 42 whose one end is swingably connected to the tailstock 30 via a pin 41, and the other end of the toggle member 42 is connected via a pin 43. To the first toggle arm 44. The first toggle arm 44 is connected to the movable die plate 20 via the pin 24.

[0005] A second toggle arm 46 is connected to the center of the toggle member 42 via a pin 45, and the second toggle arm 46 is connected to a crosshead 50 via a pin 47.
Linked to The crosshead 50 includes a ball nut 52
And screwed into the ball screw 60. This ball screw 6
0 is supported by the tailstock 30 via the bearing 62. In this electric injection molding machine, the ball screw 6
A structure is provided in which two sets of toggle mechanisms 40 including 0 are arranged in the vertical direction.

On the outside of the tail stock 30, a mounting seat 3 is provided.
2, two servo motors 80 are attached. Each servo motor 80 is connected to the drive belt 8 via a pulley 82.
4, the drive belt 84 drives the drive pulley 90 attached to the ball screw 60. The two servo motors 80 are simultaneously controlled to drive the two ball screws 60 to open and close the movable die plate 20 via the toggle mechanism 40. Timing pulleys 92 are attached to the ends of the two ball screws 60 and are connected by a timing belt 94. The provision of the timing belt 94 ensures that the two ball screws 60 rotate synchronously.

[0007]

When the crosshead 50 moves in the direction of arrow A due to the rotation of the ball screw 60,
Due to the action of the toggle mechanism 40, the movable die plate 20
When approaching the fixed die plate 10, the movable mold 22 contacts the fixed mold 12.

FIG. 9 is a graph in which the horizontal axis represents the die plate stroke (mm), and the vertical axis represents the mold clamping force (ton) and the load torque (%) of the servomotor. When the movable mold 22 is closed with respect to the fixed mold, the positions of the three pins 41, 43, and 24 of the toggle mechanism 40 are aligned on a straight line, that is, not at a so-called dead point. It is located lower than the line connecting the pins 41 and 24.

[0009] the load torque of the servo motor, as shown in the curve C ₂ in FIG. 9, the maximum and 200% of the rated capacity clamping force due to the expansion factor characteristic of the force of the toggle mechanism 40 (not shown) is about 250 tons It becomes a load and returns to zero at the dead point of the toggle (the mold clamping completion position). In normal molding, the time during which the servo motor outputs the maximum torque is short in view of the entire cycle, and the load factor of the servo motor is 100% or less. For this reason, the servomotor is not overloaded and the molding machine does not stop due to an alarm.

When molding a certain type of product, a molding program may be required to maintain the mold clamping force for a certain period of time while gradually reducing the mold clamping force with the mold. In order to execute such a machining program, it is necessary to maintain the servomotor output for a certain time in a die plate stroke in which the load torque of the servomotor exceeds 100% of the rated capacity. If a molding cycle is repeated with such a molding program, the servomotor will be overloaded and the molding machine will stop due to an alarm.
It also affects the life of the servomotor and the like. In order to respond to increasing the size of the servomotor, costs and the like also increase. Accordingly, the present invention provides an electric injection molding machine that solves the above-mentioned problems.

[0011]

The electric injection molding machine according to the present invention comprises, as basic means, a fixed die plate, a movable die plate, a tail stock, a tie bar connecting the tail stock and the fixed die plate, A toggle mechanism provided between the tailstock and the movable die plate, and first and second ball screws for driving the toggle mechanism;
The tailstock has a first servomotor mounting seat connected to the first ball screw via a belt, and a second servomotor connected to the second ball screw via a belt.
And a third servomotor mounting seat connected to the first and second ball screws via a belt.

The mounting seats for the first and second servomotors are disposed vertically above the corresponding ball screws, and the mounting seats for the third servomotor are mounted on the first and second ball screws. It is arranged below with respect to.

The third servomotor is mounted on the mounting seat via a bracket, and a belt connecting the third servomotor to the ball screw connects the first and second servomotors to the ball screw. It is arranged at a position farther from the tailstock than the belt.

[0014]

FIG. 1 is a front view showing a main part of an electric injection molding machine according to the present invention, and FIG. 2 is a left side view. The electric injection molding machine generally denoted by reference numeral 100 has a tail stock 130, and a toggle mechanism 40 is provided on the die plate side of the tail stock 130. The configuration of the toggle mechanism 40 is the same as that described above. The shaft portion 64 of the ball screw 60 disposed in parallel is connected to the tailstock 1.
A drive pulley 90 and a pulley 92 for timing are mounted to protrude out of the outside 30.

The outer surface of the tail stock 130 has a first
And two second mounting seats 32 are provided, and two electric servomotors 80 are equipped with a base 86 using bolts 87. Each servo motor 80 has a pulley 82 on its output shaft, and is connected to a corresponding pulley 90 of the ball screw 60 via a belt 84. The structure in which the two electric servomotors 80 drive the two ball screws 60 is the same as that of the electric injection molding machine described with reference to FIGS.

In the electric injection molding machine of the present invention, a third mounting seat 132 is provided outside the tail stock 130. In this mounting seat 132, while the first and second mounting seats 32 are arranged in parallel with the upper portions of the two ball screws 60, the ball screw 60 is sandwiched between the center portions of the two ball screws 60. And provided on the side opposite to the first and second mounting seats.

The mounting seat 132 has, for example, two projections formed in parallel, and is provided with a screw hole 133.
Then, in a model requiring a large clamping torque, a bracket is attached to the mounting seat 132 prepared in advance,
By attaching the third servomotor to this bracket, a model that drives two ball screws can be easily manufactured.

FIG. 3 is a front view of an electric injection molding machine provided with a third servomotor, and FIG. 4 is a left side view. The electric injection molding machine 100a includes a tail stock 130 as shown in FIG.
A third servomotor 180 is provided in addition to the two servomotors 80 shown in FIG.

The third servo motor 180 is mounted via a bracket 200 to a mounting seat 132 prepared in advance on the tail stock 130. Bracket 200
Is fixed to the mounting seat 132 by bolts 212, and the base 186 of the servomotor 180 is fixed to the bracket 200 by bolts 187. Third
The servomotor 180 is similar to the two servomotors 80 provided as standard equipment, and the use of the servomotors is shared.

The mounting shaft 64 of the two ball screws 60 has
The drive pulley 190 is attached instead of the timing pulley, and the belt 184 is stretched between the drive sprockets 182 of the third servomotor 180. Since the two ball screws 60 are driven by three servomotors,
Large torque can be generated. Further, since the two ball screws are belt-hung by three servomotors, the driving timing is also synchronized.

FIGS. 5A and 5B are three views showing the details of the third servomotor mounting bracket 200, wherein FIG. 5A is a plan view, FIG. 5B is a front view, and FIG. 5C is a right side view. The bracket 200 has a plate-shaped main body 210 and a support member 220 projecting at right angles from both sides of the main body 210. Body 2
10 is provided with a bolt hole 211, which is fixed to the mounting seat 132 by a bolt 212 using a screw hole of the mounting seat.

At the tip of the support member 220, a screw hole 221 is provided.
Are provided, and the base 18 of the third servomotor 180 is provided.
6 is fixed by bolts 187. This bracket 2
00, the third servomotor 180 can be attached to the tailstock 130 using the mounting seat 13 prepared in advance.
2 can be easily installed.

FIG. 6 is a perspective view illustrating the mounting structure of the third servomotor 180. Third servo motor 18
0 is fixed to the base 186 by screws 188, and the base 186 is fixed to the bracket 200 by bolts 187. This mounting structure is the same for the first and second servomotors 80.

[0024]

As described above, according to the present invention, in an electric injection molding machine in which two ball screws are driven by one servo motor, a tail stock is directly attached to each ball screw. In addition, a mounting seat for a third servomotor is provided. Therefore, when producing a model that needs to maintain the mold clamping force in a region where the load torque on the servomotor is large for a long time, a third servomotor is provided on the mounting seat prepared in advance, By employing a configuration in which two ball screws are driven by a belt, a large servomotor can share the torque load. Therefore, a large load torque can be endured by a small servomotor.

A model having two servo motors,
Since the three models can be configured by a common member including the tailstock, productivity can be improved and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing a main part of the present invention.

FIG. 2 is a left side view showing a main part of the present invention.

FIG. 3 is a front view showing a main part of the present invention.

FIG. 4 is a left side view showing a main part of the present invention.

FIG. 5 is a three side view of the mounting bracket.

FIG. 6 is a perspective view showing a mounting structure of a servomotor.

FIG. 7 is a front view of an electric injection molding machine to which the present invention is applied.

FIG. 8 is a left side view of the electric injection molding machine to which the present invention is applied.

FIG. 9 is a view showing the operation of the present invention.

[Explanation of symbols]

 Reference Signs List 10 fixed die plate 20 movable die plate 30 tail stock 32 first and second mounting seats 40 toggle mechanism 50 crosshead 60 ball screw 70 tie bar 80 servo motor 100 electric injection molding machine 130 tail stock 132 third mounting seat

Claims (3)

[Claims] 1. A fixed die plate, a movable die plate, a tail stock, a tie bar connecting the tail stock and the fixed die plate, a toggle mechanism provided between the tail stock and the movable die plate, and a toggle mechanism. First and second ball screws to be driven are provided, and the tailstock is provided with a mounting seat for a first servomotor connected to the first ball screw via a belt, and a belt for the second ball screw. An electric injection molding machine comprising: a mounting seat for a second servomotor connected via a belt; and a mounting seat for a third servomotor connected via a belt to the first and second ball screws. 2. A mounting seat for the first and second servomotors is disposed vertically above the corresponding ball screw, and a mounting seat for the third servomotor is provided with the first and second ball screw. The electric injection molding machine according to claim 1, wherein the electric injection molding machine is disposed below with respect to. 3. A third servomotor is mounted on a mounting seat via a bracket, and a belt connecting the third servomotor and the ball screw connects the first and second servomotors to the ball screw. The electric injection molding machine according to claim 1, wherein the electric injection molding machine is disposed at a position farther from the tailstock than the belt.