JP5473281B2 - Molding machine - Google Patents

Description

  The present invention relates to a molding machine such as an injection molding machine and a die casting machine, and more particularly, to a mounting structure for a base frame of a fixed die plate to which a fixed mold is mounted.

  In recent years, an injection molding machine having a mold clamping mechanism called a moment-free mold clamping mechanism (registered trademark) has been proposed. This mold clamping mechanism supports the fixed die plate with its axis passing through the central axis of the fixed die plate or in the vicinity thereof, parallel to the mold mounting surface of the fixed die plate, and parallel to the base surface of the apparatus. More specifically, two support legs are fixed in parallel on the base frame, and the support shaft is supported on the support legs via bearings. It is to be supported rotatably (see Patent Document 1).

With this mold clamping mechanism, when the injection nozzle is pressed against the back of the fixed die attached to the fixed die plate by aligning the axis of the injection nozzle with the central axis of the fixed die plate, the fixed die plate Is not inclined forward, abnormal wear of the guide pins and bushes provided between the fixed side mold and the movable side mold can be prevented, and it is not necessary to increase the clamping force more than necessary. The mold will not be damaged even if foreign objects are caught. In addition, when mold clamping is performed, the fixed die plate and the movable die plate do not deform asymmetrically in the vertical direction, so a uniform mold clamping force acts between the fixed side mold and the movable side mold, Precision molding becomes possible.
Japanese Patent No. 3635220

  However, this type of conventional mold clamping mechanism requires two support legs to be fixed in parallel on the base frame, and one each between the two support legs and the fixed die plate. Since a total of two bearings are required, there is a problem that the structure becomes complicated and the cost of the molding machine increases.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a molding machine that has a simple structure and can be implemented at low cost, and can mold a high-quality molded product. is there.

In order to achieve this object, the present invention achieves a fixed die plate and a tail stock that are arranged opposite to each other at a predetermined interval on a base frame, and a plurality of both ends fixed to the fixed die plate and the tail stock , A movable die plate that is guided by the tie bar to move back and forth between the die plate and the tailstock, a fixed mold attached to the fixed die plate, and attached to the movable die plate In the molding machine provided with the movable mold, a single spherical bearing is disposed on or near a straight line passing through the center of gravity of the fixed die plate and perpendicularly to the lower surface of the fixed die plate. One of the fixed die plate is supported on the base frame via a spherical bearing, to allow moving the fixed die plate 3 dimensionally It is characterized in.

  According to such a configuration, since the fixed die plate is supported on the base frame via one spherical bearing, the support legs, which are indispensable constituent elements in the prior art, can be omitted, and the number of bearings can be reduced to a minimum one. In addition, the structure of the mold clamping mechanism and thus the molding machine can be simplified and the cost can be reduced. In addition, since one spherical bearing is disposed on or near a straight line that passes through the center of gravity of the fixed die plate and perpendicularly to the lower surface of the fixed die plate, The fixed die plate can be rotated in any direction with the set position as the center of rotation. Therefore, when the clamping force and the pressing force of the injection nozzle act on the fixed die plate, the posture of the fixed die plate is automatically adjusted to the position where these forces reach equilibrium. The deformation and the deformation in the left-right direction can be made symmetrical, and the mold clamping force acting between the fixed side mold and the movable side mold can be made uniform.

  In the molding machine of the present invention, one spherical bearing is arranged on a straight line passing through the center of gravity of the fixed die plate and perpendicular to the lower surface of the fixed die plate, and the fixed die plate is formed as a base via the single spherical bearing. Since it is supported on the frame, the structure of the molding machine can be simplified and its cost can be reduced, and these forces can be selected according to the clamping force acting on the fixed die plate and the pressing force of the injection nozzle. Since the posture of the fixed die plate is automatically adjusted to the position where the two are balanced, the mold clamping force acting between the fixed mold and the movable mold can be made uniform, and high-precision molding is achieved. Is possible.

  Hereinafter, an embodiment of a molding machine according to the present invention will be described using an injection molding machine as an example with reference to FIGS. FIG. 1 is a configuration diagram of an injection molding machine according to the embodiment, FIG. 2 is a side view of a main part showing a support structure of a fixed die plate according to the embodiment, and FIG. 3 is a main part showing a support structure of the fixed die plate according to the embodiment. FIG. 4 is a diagram showing the effect of the injection molding machine according to the embodiment.

  As shown in FIG. 1, the injection molding machine of this example is mainly composed of an injection device 1 and a mold clamping device 2.

  The injection apparatus 1 includes a head stock 11 and a motor mounting plate 12 that are arranged on a base frame 7 to face each other with a predetermined interval, an injection electric servo motor 13 that is mounted on the motor mounting plate 12, and an injection unit. An encoder 15 provided in the electric servomotor 13 for detecting the rotation direction and amount of the injection electric servomotor 13, and four connecting bars 16 laid between the headstock 11 and the motor mounting plate 12, The ball screw mechanism 18 that converts the rotational motion of the electric servomotor 13 for injection into the linear motion of the linear motion body 17 that is guided by the connecting bar 16 and that moves back and forth between the head stock 11 and the motor mounting plate 12. A measuring servomotor 20 attached to the linear motion body 17, a screw 21 having one end connected to the measuring servomotor 20, a screw A cylinder 22 for accommodating the 1, an injection nozzle 23 provided at the distal end portion of the cylinder 22, and is mainly composed of a supply hopper 24 for raw resin in the cylinder 22. The ball screw mechanism 18 is directly connected to the motor rotor of the injection electric servomotor 13, and is screwed into the screw shaft 25 that is rotationally driven by the injection electric servomotor 13. And a nut body 26 fixed to.

  In this injection device 1, when the metering servo motor 20 is activated by a command from a control device (not shown), the screw 21 is driven to rotate integrally with the motor rotor, and accordingly, the raw material resin is supplied from the hopper 24 into the cylinder 22. Is done. The raw material resin supplied into the cylinder 22 is plasticized and kneaded by a shearing force accompanying the rotation of the screw 21 and heat from a band heater (not shown) provided on the outer periphery of the cylinder 22, and sequentially toward the tip side of the cylinder 22. Be transported. As the amount of resin transferred to the tip side of the cylinder 22 increases, the back pressure acting on the screw 21 increases, so that the back pressure is detected by an appropriate sensor to be plasticized and kneaded. Resin can be weighed. When it is determined that the plasticized and kneaded resin has reached a predetermined amount, the control device (not shown) outputs a drive command signal to start the injection electric servo motor 13. As a result, the screw shaft 25 of the ball screw mechanism 18 is rotationally driven integrally with the motor rotor, and the nut body 26 screwed to the screw shaft 25 and the linear motion body 17 fixed to the nut body 26 are moved forward and injected. The nozzle 23 is pressed against the fixed mold 38, and the plasticized and kneaded resin is injected from the injection nozzle 23 into the mold.

  As shown in FIG. 1, the mold clamping device 2 includes a fixed die plate 31 and a tail stock 32 fixed to each other on the base frame 7 with a predetermined interval therebetween, and both ends of the fixed die plate 31 and the tail stock 32. The four tie bars 33 fixed to the tie bar, the movable die plate 34 guided by the tie bar 33 to move forward and backward between the fixed die plate 31 and the tail stock 32, and the tail stock 32 and the movable die plate 34 are connected. A toggle link mechanism 35, a mold clamping electric servomotor 36 mounted on the tailstock 32, a ball screw mechanism 37 that converts the rotational motion of the mold clamping electric servomotor 36 into a straight motion and transmits it to the toggle link mechanism 35. It has. A fixed die 38 is mounted on the fixed die plate 31, and a movable die 39 is mounted on the movable die plate 34.

  As shown in FIGS. 2 and 3, the fixed die plate 31 is supported on the base frame 7 via a spherical bearing 50. Only one spherical bearing 50 is disposed on or near a straight line Z that passes through the center of gravity G of the fixed die plate 31 and perpendicularly intersects the lower surface of the fixed die plate 31. Note that “the vicinity thereof” means a range in which substantially the same effect as that obtained when the spherical bearing 50 is arranged on the straight line Z can be obtained, for example, a tolerance range that is allowed in design. Accordingly, the fixed die plate 31 has the z direction around the straight line Z as the rotation center, the x direction around the straight line X passing through the set position of the spherical bearing 50 and parallel to the tie bar 33, and the set position of the spherical bearing 50. And a straight line Y orthogonal to the straight line Z and the straight line X can be rotated in the y direction.

  As shown in FIGS. 2 and 3, one end of the tie bar 33 is passed through tie bar through holes 33a provided at four corners of the fixed die plate 31, and fixed to the fixed die plate 31 with bolts 33b. The arrangement position of the tie bar 33 is a position that equally divides the circumference around the center of gravity G of the fixed die plate 31. When the four tie bars 33 are arranged in this way, the mold clamping force is equally applied to the fixed die plate 31, so that it becomes easy to mold a highly accurate molded product. However, the gist of the present invention is not limited to this, and depending on the shape of the fixed die plate 31, the arrangement position of each tie bar 33 may be shifted from the position where the circumference around the center of gravity G is equally divided. Is possible.

  As shown in FIG. 1, the toggle link mechanism 35 includes a B link 41 whose one end is rotatably connected to the tail stock 32, and one end which is rotatably connected to the movable die plate 34. An A link 42 that is pin-coupled so that its end side rotates relative to the other end side of the B link 41, a cross head 43 that receives the driving force of the mold clamping electric servo motor 36 via a ball screw mechanism 37, One end is rotatably coupled to the cross head 43 and the other end is composed of a C link 44 that is pin-coupled so as to rotate relative to the intermediate portion of the B link 41. The toggle link mechanism 35 of this example is a link mechanism having a five-point pivot structure having an A link 42, a B link 41, and a C link 44, but the gist of the present invention is limited to this. However, it is of course possible to provide other types of toggle link mechanisms.

  When the mold clamping device 2 drives the mold clamping electric servo motor 36 and advances the cross head 43 to the fixed die plate 31 side via the ball screw mechanism 37, the A link 42 and the B link as shown in FIG. 41 extends in a straight line, the movable die plate 34 advances toward the fixed die plate 31, and the fixed side die 38 and the movable side die 39 are clamped. As a result, a required mold cavity 40 is formed between the fixed side mold 38 and the movable side mold 39, so that the injection material 1 can be injected into the mold cavity 40 by the injection apparatus 1. From this state, when the mold clamping electric servo motor 36 is driven and the cross head 43 is retracted to the tail stock 32 side via the ball screw mechanism 37, the A link 42 and the B link 41 are folded and the movable die is folded. The plate 34 moves backward toward the tail stock 32, and the fixed side mold 38 and the movable side mold 39 are opened. Thereby, it is possible to take out the molded product using the extrusion device 3.

  Since the molding machine of this example supports the fixed die plate 31 on the base frame 7 via one spherical bearing 50, it is an essential configuration in a molding machine equipped with a conventional moment-free clamping mechanism (registered trademark). The supporting leg that was a requirement can be omitted, and the number of bearings can be reduced to one. Therefore, simplification of the configuration of the molding machine and cost reduction can be achieved. Further, since one spherical bearing 50 is disposed on or near the straight line Z passing through the center of gravity G of the fixed die plate 31 and perpendicular to the lower surface of the fixed die plate 31, this straight line Z is set as the rotation center. Rotates a straight line Y that passes through the set position of the spherical bearing 50 in the z direction and that is orthogonal to the straight line Z and the straight line X through the set direction of the straight line X that is parallel to the tie bar 33 and the set position of the spherical bearing 50. It can rotate in the y direction around the center. Therefore, when a clamping force is applied to the fixed die plate 31, the posture of the fixed die plate 31 is automatically adjusted to a position where these forces reach equilibrium as shown in FIG. The deformation in the vertical direction and the deformation in the left-right direction are symmetrical, and the clamping force acting between the fixed mold 38 and the movable mold 39 can be made uniform, so that high quality molding can be performed. Is possible. The same applies when the clamping force and the pressing force of the injection nozzle 23 are applied to the fixed die plate 31.

  In the above-described embodiment, the injection type electric servo motor 13 is directly connected to the screw shaft 25 of the ball screw mechanism 18, and the mold clamping electric servo motor 36 is directly connected to the screw shaft of the ball screw mechanism 37. Although the present invention has been described by way of example, the gist of the present invention is not limited to this, and the present invention can be similarly applied to a belt-driven molding machine in which an electric servo motor and a ball screw mechanism are connected via a belt. .

It is a block diagram of the injection molding machine which concerns on embodiment. It is a principal part side view which shows the support structure of the fixed die plate which concerns on embodiment. These are the principal part front views which show the support structure of the fixed die plate which concerns on embodiment. It is a figure which shows the effect of the injection molding machine which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection device 2 Mold clamping device 7 Base frame 31 Fixed die plate 32 Tail stock 33 Tie bar 34 Movable die plate 35 Toggle link mechanism 36 Electric servo motor for mold clamping 37 Ball screw mechanism 38 Fixed side die 39 Movable side die 50 Spherical bearing

Claims (1)

A fixed die plate and a tail stock that are arranged on the base frame to face each other at a predetermined interval, a plurality of iver fixed at both ends to the fixed die plate and the tail stock, and guided by the tie bar, A molding machine comprising a movable die plate that moves back and forth between a die plate and the tailstock, a fixed mold attached to the fixed die plate, and a movable mold attached to the movable die plate In
One spherical bearing is disposed on or near a straight line passing through the center of gravity of the fixed die plate and perpendicularly to the lower surface of the fixed die plate, and the fixed die plate is placed on the base via the single spherical bearing. A molding machine supported on a frame and capable of moving the fixed die plate three-dimensionally .

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