WO2015119356A1

WO2015119356A1 - Device for controlling valve of injection molding apparatus

Info

Publication number: WO2015119356A1
Application number: PCT/KR2014/010002
Authority: WO
Inventors: Won Sik Lee; Hyung Woo Lee
Original assignee: Yudostar Co., Ltd.
Priority date: 2014-02-06
Filing date: 2014-10-23
Publication date: 2015-08-13
Also published as: KR20150092958A; KR101560146B1; JP2017505248A

Abstract

Provided is a device for controlling a valve of an injection molding apparatus. The device for controlling the valve of the injection molding apparatus, which operates the plurality of valve pins for selectively opening or closing a raw material injection hole defined in a mold, includes a motor generating a rotation force, a plate assembly linearly moving by rotation of the motor and to which the plurality of valve pins are coupled, an accommodation part defined by recessing at least one portion of the plate assembly, and a power transmission unit coupled to the motor to transmit the rotation force of the motor into the plate assembly. The power transmission unit includes an eccentric part disposed inside the accommodation part to eccentrically rotate.

Description

DEVICE FOR CONTROLLING VALVE OF INJECTION MOLDING APPARATUS

Embodiments relate to a device for controlling a valve of an injection molding apparatus.

In general, injection molding apparatuses are used to mold various components to be mass-produced through an injection molding process in which thermoplastic raw materials are heated and melted and then injected into a mold from a nozzle at a high pressure. Such an injection molding apparatus may include an injection device configured to inject a raw material, such as a nozzle or the like, and a valve device configured to open or close the nozzle according to whether the raw material is injected.

Fig. 1 illustrates constitutions of an injection molding apparatus according to the related art.

An injection molding apparatus according to the related art includes a fixed mold 2 fixed at a predetermined position and a movable mold 3 that is movable toward the fixed mold 2. In a state that the movable mold 3 moves to be coupled or adjacent to the fixed mold 2, an injection part 8 having a shape corresponding to that of a product to be manufactured by the injection molding is disposed between the fixed mold 2 and the movable mold 3. A predetermined raw material is injected to manufacture a product having a desired shape.

The fixed mold 2 includes a raw material supply part 4 into which a resin-type raw material is supplied, a flow path 5 along which the raw material injected from the raw material supply part 4 flows, and a nozzle 6 communicating with the flow path 5 and extending toward the injection part 8. Also, an injection hole 7 through which the raw material is injected toward the injection part 8 is formed in an end of the nozzle 6.

The nozzle 6 includes a valve pin 9 that is provided as a “valve” or “valve device” that is linearly movable to selectively open and close the injection hole 7.

The fixed mold 2 further includes a motor device 10 supplying a driving force for the movement of the valve pin 9. The motor device 10 includes a driving part including a stator and a rotor and a rotation shaft 11 that is rotatable together with the rotor.

Also, the motor device 10 further includes a coupler 12 coupled to the rotation shaft 11 and a pin holder 13 connecting the coupler 12 to the valve pin 9. The coupler 12 and the pin holder 13 may be screw-coupled to each other, and the pin holder 13 may linearly move while the coupler 12 rotates in a predetermined direction.

That is, the rotational movement of the rotation shaft 11 may be converted into linear movement through the coupler 12 and the pin holder 13, and the valve pin 9 coupled to the pin holder 13 may linearly move together with the pin holder 13.

Fig. 1 illustrates a state in which the valve pin 9 closes the injection hole 7. In this state, when the motor device 10 is driven to allow the rotor to rotate in a predetermined direction, the valve pin 9 may move upward with respect to Fig. 1 by the power transmission of the coupler 12 and the pin holder 13.

When the valve pin 9 moves upward, the injection hole 7 may be opened, and the raw material may be injected into the injection part 8 through the opened injection hole 7.

According to the injection molding apparatus of the related art, the coupler and the pin holder are separately required to convert the rotational movement of the motor device into the linear movement of the valve pin, and thus the motor device may increase in volume by the coupler and the pin holder.

Thus, as the motor device increase in volume, the fixed mold for accommodating the motor device may increase in size, resulting in increase of material costs expended for manufacturing a mold.

Embodiments provide a valve motor device of an injection molding apparatus having improved operation reliability through a simple structure thereof.

In one embodiment, a device for controlling a valve of an injection molding apparatus, which operates a plurality of valve pins for selectively opening or closing a raw material injection hole defined in a mold, includes: a motor generating a rotation force; a plate assembly linearly moving by rotation of the motor and to which the plurality of valve pins are coupled; an accommodation part defined by recessing at least one portion of the plate assembly; and a power transmission unit coupled to the motor to transmit the rotation force of the motor into the plate assembly, wherein the power transmission unit includes an eccentric part disposed inside the accommodation part to eccentrically rotate.

The eccentric part may include: a first rotation part rotating with respect to a virtual first central line; and a second rotation part extending from the first rotation part, the second rotation part having a virtual second central line that is spaced apart from the first central line.

The second rotation part may rotate with a rotation radius that is set with respect to the first central line.

While the eccentric part rotates, when the second central line is disposed at one side of the first central line, the eccentric part may press the plate assembly in a direction of the mold, and when the second central line is disposed at the other side of the first central line, the eccentric part may press the plate assembly in a direction that is away from the mold.

The power transmission unit may further include: a driving gear coupled to the motor, the driving gear including first gear teeth; and a driven gear coupled to the driving gear, the driven gear including second gear teeth that are interlocked with the first gear teeth.

The first rotation part may include: a gear coupling part coupled to the driven gear; and a second bearing coupling part extending from the gear coupling part, the second bearing coupling part being coupled to a second bearing.

The second rotation part may include: a cylindrical eccentric body; a first bearing coupling part extending from the eccentric body, the first bearing coupling part being coupled to a first bearing; and a first nut coupling part extending from the first bearing coupling part and to which a first fixing nut is coupled.

The power transmission unit may include a timing belt or chain member.

The device may further include a reducer coupled to a side of the motor to attenuate the rotation force of the motor.

The power transmission unit may further include: a coupler having an insertion hole into which at least one portion of the reducer is inserted; and a rotation shaft coupled to the coupler, wherein the reducer may be coupled to one side of the coupler, and the rotation shaft may be coupled to the other side of the coupler.

The device may further include a base block including a guide bar for guiding the linear movement of the plate assembly and a through part.

The plate assembly may include a guide accommodation part into which the guide bar of the base block is accommodated, and each of the guide bar and the guide accommodation part may be provided in plurality.

The eccentric part may pass through the through part to extend to the inside of the accommodation part.

The device may further include: a nozzle block disposed on a side of the mold, the nozzle block having a pin insertion hole to which the valve pin is coupled; and a nozzle part coupled to the nozzle block to allow a raw material to flow therethrough, wherein the valve pin may be movably coupled to the inside of the nozzle part.

In another embodiment, a device for controlling a valve of an injection molding apparatus, which operates a plurality of valve pins for selectively opening or closing a raw material injection hole defined in a mold, includes: a motor generating a rotation force; an eccentric part eccentrically rotating by operation of the motor; a plate assembly linearly moving in a direction of the mold or a direction that is away from the mold according to the rotation of the eccentric part; and a plurality of valve pins coupled to the plate assembly.

The device may further include: a driving gear coupled to the motor; and a driven gear interlocked with the driving gear, wherein the eccentric part may be eccentrically coupled to the driven gear.

The eccentric part may include: a first rotation part concentrically coupled to the driven gear; and a second rotation part eccentrically coupled to the first rotation part, wherein the second rotation part may rotate with a preset radius with respect to a central line of the first rotation part.

The device may further include at least one bearing coupled to the outside of the eccentric part to reduce a friction force of the eccentric part against the plate assembly.

The device may further include a base block guiding the linear movement of the plate assembly, wherein the eccentric part may be coupled to the plate assembly through a through part of the base block.

The plate assembly may include: a plate body; and an accommodation part recessed from one surface of the plate body to extend up to the other surface of the plate body and into which the eccentric part is inserted, wherein the eccentric part may pass through the through part and the accommodation part.

According to the embodiments, the plurality of valve pins may move at the same time by the operation of the motor. As a result, since the valve injection hole is opened to inject the raw material into the mold, the injection molding may be quickly performed.

Particularly, the power transmission unit for transmitting the driving force of the motor into the valve pin may be disposed on the eccentric part to allow the valve pin to repeatedly linearly move according to the one-directional rotation of the motor, thereby improving the operation reliability.

Also, the at least one bearing may be disposed outside the eccentric shaft to reduce the frication load between the eccentric shaft and the plate assembly while the eccentric shaft rotates.

Fig. 1 is a view of an injection molding apparatus according to a related art.

Fig. 2 is a perspective view of an injection molding apparatus according to an embodiment.

Fig. 3 is an exploded perspective view of the injection molding apparatus according to an embodiment.

Fig. 4 is an exploded perspective view of a motor assembly according to an embodiment.

Fig. 5 is a perspective view of a power transmission unit according to an embodiment.

Fig. 6 is an exploded perspective view of a driving gear assembly according to an embodiment.

Fig. 7 is an exploded perspective view of an eccentric unit according to an embodiment.

Fig. 8 is a cross-sectional view taken along line I-I’ of Fig. 2.

Figs. 9A and 9B are views illustrating a state in which a valve pin closes an injection hole when an eccentric part is disposed at one position according to an embodiment.

Figs. 10A and 10B are views illustrating a state in which the valve pin opens the injection hole when the eccentric part is disposed at the other position according to an embodiment.

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, that alternate embodiments included in other retrogressive inventions or falling within the spirit and scope of the present disclosure will fully convey the concept of the invention to those skilled in the art.

Fig. 2 is a perspective view of an injection molding apparatus according to an embodiment, and Fig. 3 is an exploded perspective view of the injection molding apparatus according to an embodiment.

Referring to Figs. 2 and 3, an injection molding apparatus 100 according to an embodiment includes a mold 110 including a plurality of injection parts (see reference numeral 115 of Fig. 9B), a nozzle block 120 disposed on a side of the mold 110 and to which a nozzle part (see reference numeral 112 of Fig. 9B) is coupled, and a valve control unit for selectively controlling the injection of the raw material supplied into the injection parts 115.

The valve control unit includes a base block 130 disposed on a side of the nozzle block 120 and to which a power transmission unit 300 is coupled and a cover part 150 covering a side of the base block 130.

The base block 130 may have a hexahedron shape of which front and rear sides are penetrated or a hollow hexahedron shape. In detail, the base block 130 includes a block body 131 having a top surface, a bottom surface, a left surface, and a right surface.

The injection molding apparatus 100 further includes a plate assembly 140 that is movably disposed inside the base block 130, a motor assembly 200 providing a driving force for the movement of the plate assembly 140, and a power transmission unit 300 for transmitting the driving force of the motor assembly 200 into the plate assembly 140.

The motor assembly and the power transmission unit 300 are coupled to each other. The power transmission unit 300 includes a driving gear assembly 310 coupled to the motor assembly 200 and an eccentric unit 350 interlocked with the driving gear assembly 310.

The eccentric unit 350 of the power transmission unit 300 may be coupled to the top and bottom surfaces of the block body 131.

For this, a first through part 135 through which the power transmission unit 300 passes may be defined in the top surface of the block body 131, and a second through part 136 through which the power transmission unit 300 passes may be defined in the bottom surface of the block body 131.

The plate assembly 140 includes a plate body 141 having an accommodation part 145 in which the eccentric unit 350 is accommodated and a plurality of pins 148 coupled to a side of the plate body 141 to extend toward the mold 110.

At least one portion of the top surface of the plate body 141 may be opened to extend to the bottom surface or be recessed up to the bottom surface to form the accommodation part 145. The eccentric unit 350 is accommodated into the accommodation part 145 by passing through the first through part 135 and extends up to the second through part 136.

A second bearing (see reference numeral 376 of Fig. 7) of the eccentric unit 350 may be coupled to the first and second through

parts

135 and 136.

A plurality of pin insertion holes 125 to which the plurality of pins 148 are coupled may be defined in the nozzle block 120. The plurality of pins 148 may pass through the plurality of pin insertion holes 125, respectively. Then, the plurality of pins 148 may be movably coupled to the inside of the nozzle part 112.

When the eccentric unit 350 rotates by the driving force of the motor assembly 200, the plate assembly 140 may linearly move. At least one guide bar 137 may be disposed on the base block 130, and a guide accommodation part 147 into which the guide bar 137 is accommodated may be defined in the plate assembly 140. For example, the guide accommodation part 147 may be defined in four corners of the plate assembly 140.

The guide bar 137 may extend in a moving direction of the plate assembly 140, for example, a front/rear direction. The plate assembly 140 may move forward or backward along the guide bar 137.

Fig. 4 is an exploded perspective view of a motor assembly according to an embodiment, Fig. 5 is a perspective view of a power transmission unit according to an embodiment, Fig. 6 is an exploded perspective view of a driving gear assembly according to an embodiment, Fig. 7 is an exploded perspective view of an eccentric unit according to an embodiment, and Fig. 8 is a cross-sectional view taken along line I-I’ of Fig. 2.

Referring to Figs. 4 to 7, the motor assembly 200 according to an embodiment includes a motor 210 generating a driving force, a reducer 230 coupled to a side of the motor 210 to attenuate the rotation force of the motor 210, and a bracket on which the reducer 230 is mounted.

The bracket 250 includes a mount part 255 to which at least one portion of the reducer 230 is coupled. One surface of the bracket 250 may be penetrated to form the mount part 255.

The driving gear assembly 310 is coupled to a side of the motor assembly 200.

The driving gear assembly 310 include a coupler 312 coupled to the reducer 230. The coupler 312 has an insertion hole 315 into which at least one portion of the reducer 230 is inserted.

The driving gear assembly 310 further includes a rotation shaft 330 coupled to the coupler 312 and a driving gear 320 coupled to the outside of the rotation shaft 330.

The driving gear 320 includes a shaft through part 325 through which the rotation shaft 330 passes and a plurality of gear teeth 321 disposed on an outer circumferential surface of the driving gear 320.

The rotation shaft 320 passes through the shaft through part 325 to extend toward the coupler 312 and then be coupled to an inner surface of the coupler 312. The reducer 230 may be coupled to one side of the coupler 312, and the rotation shaft 320 may be coupled to the other side of the coupler 312.

When the motor 210 is driven, the reducer 230 rotate to reduce the rotation number of motor 210, and the rotation shaft 330 may rotate in a state where the rotation shaft 330 is coupled to the reducer 230 through the coupler 312. Also, the driving gear 320 may rotate together with the rotation shaft 330 in a predetermined direction.

The rotation shaft 330 includes a rotation shaft body 331 coupled to the block body 131 of the base block 130 and an insertion part 335 coupled to the inside of the driving gear 320.

Also, a support part 333 supporting a bottom surface of the driving gear 320 is disposed between the rotation shaft body 331 and the insertion part 335. The support part 333 may have an outer diameter greater than that of each of the rotation shaft body 331 and the insertion part 335.

The driving gear assembly 310 further includes a bearing 340 surrounding at least one portion of the rotation shaft body 331 and a nut 345 disposed under the bearing 340 and coupled to a lower portion of the rotation shaft body 331.

The bearing 340 may be coupled to a top surface of the block body 131 to reduce a friction force that is transmitted from the rotation shaft 330 to the block body 131. Also, the nut 345 may be disposed under the top surface of the block body 131 (see Fig. 8).

The rotation shaft 330 may be stably rotatably supported on the block body 131 by bearing 340 and the nut 345.

The eccentric unit 350 may be coupled to a side of the driving gear assembly 310 and thus be interlocked with the driving gear assembly 310.

In detail, the eccentric unit 350 includes a driven gear 380 coupled to the driving gear assembly 310, an eccentric part 360 eccentrically coupled to the driven gear 380 to rotate, and a plurality of

support members

371, 373, and 376 supporting the eccentric part 360 to allow the eccentric part 360 to be stably driven.

The driven gear 380 includes an eccentric through part 385 to which the eccentric part 360 is coupled and a plurality of gear teeth 381 disposed on an outer circumferential surface of the driven gear 380. For convenience of description, the gear teeth of the driving gear 320 is called “first gear teeth”, and the gear teeth 381 of the driven gear 380 is called “second gear teeth”.

The eccentric part 360 includes an eccentric body 361 having an approximately cylindrical shape and a plurality of

coupling parts

363, 364, and 366 extending toward both sides of the eccentric body 361. The plurality of

coupling parts

363, 364, and 366 may be stepped to have outer diameters different from each other.

In detail, the plurality of

coupling parts

363, 364, and 366 include a first bearing coupling part 363 to which the first bearing 371 is coupled, a first nut coupling part 364 extending from the first bearing coupling part 363 and to which the first fixing nut 373 (i.e., the support member 373) is coupled, and a second bearing coupling part 366 extending from the first nut coupling part 364 and to which the second bearing 376 is coupled.

The first bearing 371 may be disposed inside the accommodation part 145 of the plate assembly 140 to surround the first beating coupling part 363.

Also, the first fixing nut 373 may be disposed on a side of the first bearing 371 to surround the first nut coupling part 364 and also be disposed inside the accommodation part 145. A first screw thread 364 is disposed on an outer circumferential surface of the first nut coupling part 364, and a second screw thread 374 coupled to the first screw thread 365 is disposed on an inner circumferential surface of the first fixing nut 373.

The second bearing 376 is disposed on a side of the first fixing nut 373 to surround the second bearing coupling part 366 and also is coupled to the first through part 135 of the block body 131.

A first spacer 375 is disposed between the first fixing nut 373 and the second bearing 376, and a second spacer 377 is disposed between the second bearing 376 and the driven gear 380.

The first spacer 375 is disposed under the first through part 135 of the block body 131, and the second spacer 377 is disposed above the first through part 135. Also, the driven gear 380 may be supported on the second spacer 377.

The first fixing nut 373 and the second bearing 376 may be spaced apart from each other by the first spacer 375. Also, the second bearing 376 and the driven gear 380 may be spaced apart from each other by the second spacer 377.

The first bearing coupling part 363, the first nut coupling part 364, and the second bearing coupling part 366 may be disposed on both sides of the eccentric body 361, i.e., upper and lower sides of the eccentric body 361 in Fig. 7. The first bearing 371, the first fixing nut 373, and the second bearing 376 which are coupled to the lower side of the eccentric body 361 may not be illustrated in Fig. 7.

Also, the gear coupling part 368 coupled to the driven gear 380 may be disposed on the second bearing coupling part 366 that is disposed above the eccentric body 361. The gear coupling part 368 may be coupled to the inside of the eccentric through part 385.

A vertical virtual central line ℓ2 passing through a center of the eccentric body 361 and a vertical virtual central line ℓ1 passing through a center of the gear coupling part 368 may be spaced apart from each other. The virtual central line ℓ1 is called a “first central line”, and the virtual central line ℓ2 is called a “second central line”.

In detail, the driven gear 380, the gear coupling part 368, and the second bearing coupling part 366 may have the same central line, i.e., the first central line ℓ1. Also, the eccentric body 361, the first bearing coupling part 363, and the first nut coupling part 364 may have the same central line, i.e., the second central line ℓ2.

Also, the first central line ℓ1 and the second central line ℓ2 extend to be spaced apart from each other (a spaced distance S). The spaced distance S may correspond to a rotation radius of the eccentric body 361.

That is, a central line ℓ2 of the

portions

361, 363, and 364 of the eccentric part 360 that is disposed inside the accommodation part 145 and a central line ℓ1 of the

portions

366, 368, and 380 of the eccentric part 360 that is disposed outside the accommodation part 145 and coupled to the block body 131 may be spaced apart from each other.

According to the above-described configuration, when the gear coupling part 368 is coupled to the driven gear 380 to rotate, the eccentric body 361 may rotate, i.e., eccentrically rotate with a preset rotation radius S.

Here, the driven gear 380, the gear coupling part 368, and the second bearing coupling part 366 may rotate in place. The driven gear 380, the gear coupling part 368, and the second bearing coupling part 366 are called a “first rotation part”.

On the other hand, the first bearing coupling part 364 and the first nut coupling part 364 are eccentrically rotate together with the eccentric body 361. The eccentric body 361, the first bearing coupling part 363, and the first nut coupling part 364 are called a “second rotation part” or “eccentric rotation part”.

While the

eccentric rotation parts

361, 364, and 366 rotate, a predetermined force may be applied to an inner surface of the accommodation part 145 through the first bearing 371. Here, the generated friction force may be reduced by the first bearing 371.

The plate assembly 140 may move in a front/rear direction by the force transmitted into the accommodation part 145. Here, the term “front direction” may be understood as a direction in which the valve pin 148 moves in a direction of the injection part 115 of the mold 110 to close a raw material injection hole 116 (hereinafter, referred to as an “injection hole”), and the term “rear direction” may be understood as a direction in which the valve pin 148 moves in a direction that is away from the injection part 115 of the mold 110 to open the injection hole 116.

A second nut coupling part 369 to which a second fixing nut 379 (see Fig. 8) is disposed on a lower portion of the second being coupling part 366 that is disposed under the eccentric body 361. The second fixing nut 379 may be disposed under the second through part 136 of the block body 131 in a state where the second fixing nut 379 is disposed to surround the second nut coupling part 369.

Figs. 9A and 9B are views illustrating a state in which the valve pin closes the injection hole when an eccentric part is disposed at one position according to an embodiment, and Figs. 10A and 10B are views illustrating a state in which the valve pin opens the injection hole when the eccentric part is disposed at the other position according to an embodiment

Referring to Figs. 9A to 10B, an operation of a device for controlling the valve of the injection molding apparatus according to an embodiment will be described.

When the motor assembly 200 is driven to allow the driving gear assembly 300 to rotate, the eccentric unit 350 is interlocked with the driving gear 320 to rotate.

In detail, when the driven gear 380 of the eccentric unit 350 rotates, the

first rotation parts

366 and 368 of the eccentric part 360, i.e., the gear coupling part 368 and the second bearing coupling part 366 may rotate in place.

On the other hand, the

second rotation parts

361, 363, and 364 coupled to the

first rotation parts

366 and 368 may rotate with a predetermined rotation radius.

As illustrated in Fig. 9A, when a virtual second central line ℓ2 of the

second rotation parts

361, 363, and 364 is defined at a front side of a virtual first central line ℓ1 of the

first rotation parts

366 and 368, the eccentric part 360 may press the plate assembly 140 forward through the accommodation part 145.

Thus, the plate assembly 140 moves forward along the guide bar 137 of the base block 130. Also, as the plate assembly 140 moves forward, the valve pin 148 moves forward within the nozzle part 112 to close the plurality of injection holes 116 defined in the mold 110. Thus, the supply of the raw material through the plurality of injection holes 116 may be stopped.

Here, the nozzle part 112 may be provided in plurality to guide a flow of the raw material. Also, the nozzle part 112 is coupled to the nozzle block 120 to extend toward the plurality of injection holes 116 of the mold 110. Also, a plurality of injection parts 115 through which the raw material discharged through the plurality of injection holes 116 is injected may be defined in the mold 110.

When the motor assembly 200 further rotates in the state of Fig. 9A, the

second rotation parts

361, 363, and 364 may eccentrically rotate so that the virtual second central line ℓ2 moves to a rear side with respect to the virtual first central line ℓ1.

That is, as illustrated in Fig. 10A, when the virtual second central line ℓ2 of the

second rotation parts

361, 363, and 364 is defined at a rear side of the virtual first central line ℓ1 of the

first rotation parts

366 and 368, the eccentric part 360 may press the plate assembly 140 backward.

Thus, the plate assembly 140 moves backward along the guide bar 137 of the base block 130. Also, as the plate assembly 140 moves backward, the valve pin 148 moves backward within the nozzle part 112 to open the plurality of injection holes 116 defined in the mold 110. Thus, the raw material may be supplied through the plurality of injection holes 116 and then be injected at the same time through the plurality of injection parts 115.

As described above, the plate assembly 1140 may repeatedly move forward and backward by the operation of the motor assembly 200, and the plurality of valve pins 148 may selectively open or close the plurality of injection holes 116 defined in the mold 110. Therefore, the raw material may be supplied into the plurality of injection parts 115 at the same time.

Another embodiment will be proposed.

Although the driving gear and the driven gear are provided as one component of the power transmission unit for transmitting the driving force of the motor assembly into the plate assembly in the present embodiment, the present disclosure is not limited thereto. For example, a timing belt or chain member may be provided as one component of the power transmission unit.

According to the embodiments, the plurality of valve pins may move at the same time by the operation of the motor. As a result, since the valve injection hole is opened to inject the raw material into the mold to quickly perform the injection molding, the industrial applicability may be remarkable.

Claims

A device for controlling a valve of an injection molding apparatus, which operates a plurality of valve pins for selectively opening or closing a raw material injection hole defined in a mold, the device comprising:

a motor generating a rotation force;

a plate assembly linearly moving by rotation of the motor and to which the plurality of valve pins are coupled;

an accommodation part defined by recessing at least one portion of the plate assembly; and

a power transmission unit coupled to the motor to transmit the rotation force of the motor into the plate assembly,

wherein the power transmission unit comprises an eccentric part disposed inside the accommodation part to eccentrically rotate.
The device according to claim 1, wherein the eccentric part comprises:

a first rotation part rotating with respect to a virtual first central line; and

a second rotation part extending from the first rotation part, the second rotation part having a virtual second central line that is spaced apart from the first central line.
The device according to claim 2, wherein the second rotation part rotates with a rotation radius that is set with respect to the first central line.
The device according to claim 3, wherein, while the eccentric part rotates, when the second central line is disposed at one side of the first central line, the eccentric part presses the plate assembly in a direction of the mold, and

when the second central line is disposed at the other side of the first central line, the eccentric part presses the plate assembly in a direction that is away from the mold.
The device according to claim 3, wherein the power transmission unit further comprises:

a driving gear coupled to the motor, the driving gear comprising first gear teeth; and

a driven gear coupled to the driving gear, the driven gear having second gear teeth that are interlocked with the first gear teeth.
The device according to claim 5, wherein the first rotation part comprises:

a gear coupling part coupled to the driven gear; and

a second bearing coupling part extending from the gear coupling part, the second bearing coupling part being coupled to a second bearing.
The device according to claim 2, wherein the second rotation part comprises:

a cylindrical eccentric body;

a first bearing coupling part extending from the eccentric body, the first bearing coupling part being coupled to a first bearing; and

a first nut coupling part extending from the first bearing coupling part and to which a first fixing nut is coupled.
The device according to claim 1, wherein the power transmission unit comprises a timing belt or chain member.
The device according to claim 5, further comprising a reducer coupled to a side of the motor to attenuate the rotation force of the motor.
The device according to claim 9, wherein the power transmission unit further comprises:

a coupler having an insertion hole into which at least one portion of the reducer is inserted; and

a rotation shaft coupled to the coupler,

wherein the reducer is coupled to one side of the coupler, and the rotation shaft is coupled to the other side of the coupler.
The device according to claim 1, further comprising a base block comprising a guide bar for guiding the linear movement of the plate assembly and a through part.
The device according to claim 11, wherein the plate assembly comprises a guide accommodation part into which the guide bar of the base block is accommodated, and

each of the guide bar and the guide accommodation part is provided in plurality.
The device according to claim 11, wherein the eccentric part passes through the through part to extend to the inside of the accommodation part.
The device according to claim 1, further comprising:

a nozzle block disposed on a side of the mold, the nozzle block having a pin insertion hole to which the valve pin is coupled; and

a nozzle part coupled to the nozzle block to allow a raw material to flow therethrough,

wherein the valve pin is movably coupled to the inside of the nozzle part.
A device for controlling a valve of an injection molding apparatus, which operates a plurality of valve pins for selectively opening or closing a raw material injection hole defined in a mold, the device comprising:

a motor generating a rotation force;

an eccentric part eccentrically rotating by operation of the motor;

a plate assembly linearly moving in a direction that is towards the mold or a direction that is away from the mold according to the rotation of the eccentric part; and

a plurality of valve pins coupled to the plate assembly.
The device according to claim 15, further comprising:

a driving gear coupled to the motor; and

a driven gear interlocked with the driving gear,

wherein the eccentric part is eccentrically coupled to the driven gear.
The device according to claim 16, wherein the eccentric part comprises:

a first rotation part concentrically coupled to the driven gear; and

a second rotation part eccentrically coupled to the first rotation part,

wherein the second rotation part rotates with a preset radius with respect to a central line of the first rotation part.
The device according to claim 15, further comprising at least one bearing coupled to the outside of the eccentric part to reduce a friction force of the eccentric part against the plate assembly.
The device according to claim 15, further comprising a base block guiding the linear movement of the plate assembly,

wherein the eccentric part is coupled to the plate assembly through a through part of the base block.
The device according to claim 19, wherein the plate assembly comprises:

a plate body; and

an accommodation part recessed from one surface of the plate body to extend up to the other surface of the plate body and into which the eccentric part is inserted,

wherein the eccentric part passes through the through part and the accommodation part.