JP2003291173A - Injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding machine which can obtain necessary, minimum nozzle touching force even during high speed injection. <P>SOLUTION: A barrel 51 for housing a screw, a linear motor 52 for moving the screw in the axial direction, a frame structure 50, and a connection member 120, are provided. The frame structure 50 has a 71 to which the barrel 51 is fixed and a seat 76 fitted with a nozzle touch mechanism 116. The connection member 120 connects the seat 76 and the fixed side support member 63 of the linear motor 52 to each other. The connection member 120 extends from the seat 76 toward the linear motor 52 and covers at least the side of the movable side member 82 of the linear motor 52. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine equipped with a linear motor as a drive source for injection operation.

[0002]

2. Description of the Related Art In a conventional electric injection molding machine 1 of which an example is shown in FIG. 5, a front plate 3 and a rear plate 4 are provided on a fixed base 2, and the plates 3 and 4 are connected to each other by a tie bar 5. . The base of the barrel 6 is fixed to the front plate 3. The screw 7 housed inside the barrel 6 can be rotated by a motor 8.

The base of the screw 7 is rotatably supported by an intermediate plate 10 by a bearing 9. The intermediate plate 10 and the motor 8 can move linearly along the tie bar 5. The intermediate plate 10 and the motor 8 can be reciprocated along the tie bar 5 in the direction of arrow A in FIG. 5 by a linear movement mechanism 13 including a ball screw 11 and a servo motor 12, for example.

A mold 16 is attached to the fixed platen 15. With the nozzle touch mechanism (not shown), the screw 7 is moved forward by the linear motion mechanism 13 while the nozzle 6 at the tip of the barrel 6 is in contact with the injection port of the mold 16, so that the molten resin is removed from the nozzle 6 by the linear movement mechanism 13. Mold 16
To be filled.

[0005]

In the conventional injection molding machine 1, when a large output is generated by the linear motion mechanism 13 at the time of high-speed injection, the rear plate 4 is moved in the F ₀ direction by the reaction force F ₀ generated at the time of injection. There is a concern that it will be displaced. In particular, when a large-output linear motor suitable for high-speed injection is used as a drive source for injection operation, a large reaction force F ₀ is generated on the fixed side member of the linear motor, and the rear plate 4 is deformed. there is a possibility.

The reaction force F ₀ acts in a direction of separating the nozzle 6 from the mold 16. Since the conventional injection molding machine does not have a structure in which the reaction force F ₀ is taken into consideration, the nozzle touch force is insufficient at the time of high-speed injection, and the resin may leak from the nozzle. For this reason, particularly in an injection molding machine that uses a high-output linear motor as a drive source for injection operation, it is necessary to make the nozzle touch force larger than that of a normal injection molding machine.

In order to increase the nozzle touch force in the conventional injection molding machine, it is necessary to use a ball screw mechanism, a hydraulic cylinder, or the like that constitutes the nozzle touch mechanism, which has a larger output. In addition to the large size and weight, the manufacturing cost also increases.

Therefore, an object of the present invention is to provide an injection molding machine which can obtain an appropriate nozzle touch force even during high-speed injection.

[0009]

The injection molding machine of the present invention comprises:
A barrel for accommodating the screw therein, a linear motor for moving the screw in the axial direction, a frame structure having a portion to which the barrel is fixed and a pedestal portion provided with a nozzle touch mechanism, the pedestal portion and the linear And a connecting member for connecting the fixed side supporting member of the motor.

In a preferred mode of the present invention, the connecting member extends from the pedestal portion in the direction of the linear motor,
It also serves as a cover that covers at least the side surface of the movable member of the linear motor.

Further, in a preferred aspect of the present invention, the pedestal portion and the fixed platen of the mold clamping device are coupled to each other by a rod member of the nozzle touch mechanism.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. The electric injection molding machine 20 shown in FIG. 1 includes an injection device 21 located on the right side in FIG. 1 and a mold clamping device 22 located on the left side in FIG.

The mold clamping device 22 includes a fixed platen 25, a movable platen 26, and a drive mechanism 28 (only part of which is shown) for moving the movable platen 26 along the tie bar 27. A fixed mold 30 (shown in FIG. 2) is attached to the fixed platen 25, and a movable mold 31 is attached to the movable platen 26.

As shown in FIG. 2, an injection device 21 is provided on the fixed base 40. The injection device 21 has a slide base 42 that can reciprocate along a guide rail 41 provided on a fixed base 40.
It is possible to move in the front-back direction (axial direction indicated by arrow X in FIG. 2).

The injection device 21 includes a frame structure 50, a barrel 51, a voice coil type linear motor 52 which is an example of a driving device, a screw rotating mechanism 53 and the like. The screw 54 is inserted into the barrel 51.
A frame structure 50, a front stand 62, and a rear stand 63 are fixed on the slide base 42.

The frame structure 50 includes a first portion 71 that supports the base of the barrel 51, a second portion 72 that is connected to the linear motor 52 side, and the first portion 71 and the second portion 72. A pair of left and right connecting walls 7 that connect both sides of each
3, 74, the bottom wall 75, and the nozzle touch mechanism 1 described later.
It has a pair of left and right pedestals 76 and the like on which 16 is provided.

That is, the frame structure 50 includes first and second portions 71 and 72, connecting walls 73 and 74, and a bottom wall 7.
5, the pedestal portion 76 and the like are integrally molded with each other by casting to form a box with a bottom as a whole. The pedestal portion 76 is formed in a three-dimensional shape capable of exerting great rigidity so as not to be easily deformed by an external force applied at the time of injection.

A voice coil type linear motor 52, which is an example of a drive device, includes a stationary member 81 including a plurality of electromagnetic coils 80 provided in parallel between front and rear stands 62 and 63, and an electromagnetic coil 80. The movable side member 82 including the magnet driven in the X direction by the magnetic field is provided. The magnet here is generally a permanent magnet, but may be an electromagnet.

The movable member 82 of the linear motor 52 can reciprocate between the stands 62 and 63 along a guide member 83 provided on the slide base 42. The connecting plate 85, which is a part of the movable member 82,
The output shaft 86 is connected.

Near the base of the barrel 51, a hopper 88 for supplying a resin, which is a material of the injection-molded article, is provided.
The hopper 88 is attached to the first portion 71 of the frame structure 50. A heater (not shown) for heating and melting the resin is attached to the barrel 51.

The screw rotating mechanism 53 includes a screw 5
4, a shaft 90 to which 4 is connected, a sleeve member 91 fitted to the shaft 90, a motor 92 for rotating the sleeve member 91, a first bearing portion 93, and a second bearing portion 93.
Bearing portion 94 and the like.

More specifically, as schematically shown in FIG. 4, a spline portion 95 along the axial direction is formed on the outer peripheral portion of the shaft 90. By fitting the sleeve member 91 to the spline portion 95, the sleeve member 91
On the other hand, the shaft 90 can relatively move in the axial direction, and the shaft 90 and the sleeve member 91 can integrally rotate.

The sleeve member 91 is rotatably supported by the intermediate support wall 100 by the first bearing portion 93. The intermediate support wall 100 is the bottom wall 75 of the frame structure 50.
It is fixed to.

A motor supporting portion 101 is provided on the frame structure 50.
Is provided, and the motor 92 is mounted on the motor support portion 101. A power transmission member 105 such as a belt is wound between a drive pulley 103 attached to the output shaft 102 of the motor 92 and a driven pulley 104 attached to the sleeve member 91. Therefore, the motor 92
The sleeve member 91 can be rotated by rotating the output shaft 102. When the sleeve member 91 rotates, the shaft 9 fitted in the spline portion 95
Since 0 rotates, the screw 54 rotates.

The rear end of the shaft 90 is connected to the output shaft 86 of the linear motor 52 by a connecting mechanism 106 having a second bearing 94. This connection mechanism 1
Reference numeral 06 connects the output shaft 86 and the shaft 90 to each other, and allows relative movement of the both in the rotational direction. That is, the linear motion of the output shaft 86 in the axial direction can be transmitted to the shaft 90, and the rotational motion of the shaft 90 is not transmitted to the output shaft 86.

Nozzle 1 formed at the tip of barrel 51
10 is located on the center line of the hole 111 formed in the fixed platen 25. Fixed platen 25 and frame structure 50
Are connected to each other by, for example, a ball screw 115 and a nozzle touch mechanism 116 using a servomotor or the like. By driving the nozzle touch mechanism 116, the injection device 21 is moved to the guide rail 4 with respect to the fixed platen 25.
It can be moved forward and backward along 1. When the injection device 21 is advanced to a predetermined position, the tip of the nozzle 110 is brought into contact with the injection port 30a of the stationary mold 30.

The pedestal portion 76 of the frame structure 50 and the fixed platen 25 of the mold clamping device 22 extend forward of the pedestal portion 76 of the rod member of the nozzle touch mechanism 116 (screw shaft 11).
7) are connected to each other.

The base 76 and the rear stand 63 are connected to each other by a pair of left and right connecting members 120. The pair of left and right connecting members 120 respectively include the pedestal 7
6 extends in the direction of the linear motor 52. The connecting member 120 also functions as a cover that covers the side surface of the movable-side member 82 of the linear motor 52 and a part of the nozzle touch mechanism 116.

One end 121 of each connecting member 120 is fixed to the pedestal 76 by a fixing member 122 such as a bolt. The other end 123 of each connecting member 120 is fixed to the rear stand 63 by a fixing member 124 such as a bolt. The rear stand 63 has a function of supporting the rear end of the fixed-side member 81 of the linear motor 52 on the base 42, and corresponds to the fixed-side support member referred to in the present invention.

Next, the operation of the injection molding machine 20 having the above structure will be described. Molds 30 and 31 by the mold clamping device 22
And the injection device 21 is closed by the nozzle touch mechanism 116.
By advancing toward the fixed platen 25,
The tip of the nozzle 110 is connected to the injection port 30 of the fixed mold 30.
Contact a.

The electromagnetic coil 80 of the linear motor 52
The electric current is supplied to the movable side member 82 of the linear motor 52, as schematically shown in FIG. When the movable member 82 moves forward, the shaft 90 moves forward via the output shaft 86, and the screw 54 further moves forward, so that the molten resin previously measured in the barrel 51 is moved from the tip of the nozzle 110 by the screw 54. It is extruded and filled in the molds 30 and 31.

As shown in FIG. 4, when the movable side member 82 of the linear motor 52 advances in the direction indicated by the arrow F1 during injection, the reaction force F2 acts on the fixed side member 81. Therefore, the rear stand 63 also receives the reaction force F2. The reaction force F2 is transmitted to the pedestal portion 76 of the frame structure 50 via the connecting members 120 fixed to both side portions of the rear stand 63, and is supported by the pedestal portion 76.

Therefore, the rear stand 63 is prevented from bending in the direction of the reaction force F2. Moreover, the pedestal portion 76 is connected to the fixed platen 25 via the screw shaft 117 of the nozzle touch mechanism 116. Therefore, even when the reaction force F2 is generated by the operation of the linear motor 52 during high-speed injection, a predetermined nozzle touch force can be maintained, and problems such as resin leak from the tip of the nozzle 110 during injection can be avoided. can do.

After the resin injected into the molds 30, 31 is cooled, the movable side member 82 of the linear motor 52 is retracted, whereby the screw 54 is retracted by a predetermined amount.
Further, by rotating the shaft 90 with the motor 92, the screw 54 is rotated, and the molten resin is kneaded while being sent to the tip side of the barrel 51, and the molten resin is measured. Then, the molds 30 and 31 are opened, and the molded product is ejected by the ejector mechanism to complete the injection molding process for one cycle.

Since the frame structure 50 is a box-shaped integrally molded product (for example, a cast product), the injection molding machine 20 has a large proof strength against a tensile load in the front-rear direction and the vertical direction. And, it is possible to exert great rigidity in the left-right direction. Therefore, even if the screw 54 linearly moves at high speed by the linear motor 52, the frame structure 50
Can be suppressed from vibrating or deforming.

The motor 92 for screw rotation is attached to the motor support portion 101 provided on the frame structure 50 having high rigidity.
Is fixed, and the shaft 90 and the sleeve member 91 are fitted to each other via the spline portion 95, so that when the screw 54 is linearly moved in the axial direction by the linear motor 52, the motor 92 itself It stays on the motor support 101 without linear movement. Therefore, the movable mass (inertia mass) that linearly moves integrally with the screw 54 can be reduced, and the linear reciprocating motion by the linear motor 52 can be further speeded up.

For these reasons, the cycle time required for injection molding can be further shortened. Also,
By adopting the integral frame structure 50 formed by casting or the like, the number of parts constituting the frame structure 50 can be reduced.

In carrying out the present invention, the components of the present invention such as the connecting member, the nozzle touch mechanism and the pedestal of the frame structure are variously modified without departing from the scope of the present invention. It goes without saying that it can be carried out. Further, the number and positions of the nozzle touch mechanisms can be changed as needed.

In addition to the ball screw described in the above embodiment, the nozzle touch mechanism may use a hydraulic cylinder that hydraulically drives the rod member in the axial direction, or a combination of a disc spring and a rod member. May be. Further, the present invention can be applied to an injection molding machine for synthetic resin products and an injection molding machine for metal products.

[0040]

According to the first aspect of the present invention, it is possible to suppress deformation of the fixed side support member of the linear motor due to the reaction force generated at the time of injection, and it is possible to avoid insufficient nozzle touch force. At the same time, the tip of the nozzle can be reliably brought into contact with the mold.

According to the second aspect of the present invention, the connecting member also serves as the cover, so that the connecting member can cover at least a part of the movable side member of the linear motor and the nozzle touch mechanism.

According to the third aspect of the present invention, the reaction force generated at the time of injection is transmitted to the pedestal through the connecting member, and the reaction force is generated between the fixed platen and the nozzle touch mechanism provided in the pedestal. Since the reaction force can be received by, even if a high-output linear motor suitable for high-speed injection is adopted, it is possible to avoid a shortage of the nozzle touch force during injection.

[Brief description of drawings]

FIG. 1 is a perspective view of an injection molding machine showing an embodiment of the present invention.

FIG. 2 is a sectional view of a part of the injection molding machine shown in FIG. 1 taken along the axial direction.

FIG. 3 is a plan view of the injection molding machine shown in FIG.

FIG. 4 is a cross-sectional view schematically showing a state where the screw of the injection molding machine shown in FIG. 1 has advanced.

FIG. 5 is a sectional view of a conventional injection molding machine.

[Explanation of symbols] 20 ... Injection molding machine 21 ... Injection device 22 ... Mold clamping device 25 ... Fixed platen 50 ... Frame structure 51 ... barrel 52 ... Linear motor 54 ... screw 63 ... Rear stand (fixed side support member) 76 ... Pedestal 81 ... Fixed member 82 ... Movable side member 116 ... Nozzle touch mechanism 120 ... Connection member

Continued front page    (72) Inventor Katsuyoshi Kido             2068 Ooka, Numazu City, Shizuoka Prefecture Toshiba Machine Co., Ltd.             In the company (72) Inventor Harumichi Tokuyama             2068 Ooka, Numazu City, Shizuoka Prefecture Toshiba Machine Co., Ltd.             In the company F-term (reference) 4F206 AM04 JA07 JM03 JN09 JQ06                       JT03 JT32

Claims (3)

[Claims] 1. A barrel for accommodating a screw, a linear motor for moving the screw in an axial direction, a frame structure having a portion to which the barrel is fixed and a pedestal portion provided with a nozzle touch mechanism, and the pedestal portion. An injection molding machine comprising: a connecting member that connects the fixed side supporting member of the linear motor to the connecting member. 2. The injection member according to claim 1, wherein the connecting member extends from the pedestal portion in the direction of the linear motor and also serves as a cover for covering at least a side surface portion of the movable side member of the linear motor. Molding machine. 3. The injection molding machine according to claim 2, wherein the pedestal portion and the fixed platen of the mold clamping device are coupled to each other by a rod member of the nozzle touch mechanism.