JP2006297860A - Electric vertical injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric vertical injection molding machine designed for minimizing its horizontal swing due to oscillation, improving the accessibility to the periphery of a nozzle, preventing the accidental fall of the device by its own weight when the belt is cut from occurring, and further, minimizing the length of an expensive ball screw for the ascent/descent of the device. <P>SOLUTION: At least two pieces of four pieces of guide bars of the injection device, are of a hollow structure, and a ball screw shaft 41 for the ascent/descent drive of the device is accommodated inside the hollow structure, and further, a driving motor 51 with a brake is directly connected with one piece of the ball screw shaft 41 without passing through a belt. In addition, the difference in the overall length of a screw cylinder part 25 to be used due to its diametral variation, is absorbed by length regulation parts 70a and 70b for. Consequently, the length of the ball screw 41 for the ascent/descent drive is minimized. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric vertical injection molding machine of a vertical clamping injection system.

Conventionally, resin melt-plasticized in a heating cylinder is injected and filled into a cavity space of a mold apparatus that is attached to a mold clamping device and fully closed, and after cooling and solidification of a molded product after injection filling, In the injection molding in which the mold is opened and the molded product is taken out from the mold apparatus, there is known a vertical mold injection type electric mold injection molding machine having a toggle type mold clamping apparatus, a mold apparatus and an injection apparatus. (For example, refer to Patent Document 1).

5 is a front view of a vertical injection molding machine schematically shown in Patent Document 1, FIG. 6 is a side view of an ascending / descending drive unit of the injection apparatus, and FIG. 7 is a cross-sectional plan view of the injection apparatus taken along arrow D in FIG. FIG. With reference to these drawings, a vertical clamping injection type electric vertical injection molding machine will be briefly described.

In FIG. 5, reference numeral 101 denotes a vertical clamping injection type electric vertical injection molding machine in which a mold clamping device 102 and an injection device 103 are arranged in series in the vertical direction.
The mold clamping device 102 includes a machine frame 111, a fixed platen 112 fixed to the upper surface of the machine frame 111, and three tie bars 114 (through the machine frame 111 and the fixed platen 112 extending in the vertical direction) ( (Only two are shown), a movable platen 113 fixed to the upper end of the tie bar 114, a toggle support 115 fixed to the lower end of the tie bar 114, and an up-and-down expansion and contraction provided between the toggle support 115 and the fixed platen 112. The movable toggle mechanism 116 and the mold clamping drive mechanism 117 which is disposed on the machine frame 111 and moves the movable platen 113 up and down by extending and contracting the toggle mechanism 116 are formed.
A fixed mold 152 is attached to the upper surface of the fixed platen 112, and a movable mold 151 is attached to the lower surface of the movable platen 113.

One end of an arm 123 is rotatably attached to the lower surface of the fixed platen 112 by a pin 118, and the other end of the arm 123 is rotatably attached to one end of the arm 124 via a pin 120. . The other end of the arm 124 is rotatably attached to a toggle support 115 that moves up and down via a pin 119.
Further, an arm 125 is attached to the cross head 126 via a pin 122, and the other end of the arm 125 is attached to the arm 123 via a pin 121.

A ball nut 127 is fixed to the cross head 126, and the ball nut 127 is screwed into a ball screw shaft 128 rotatably supported at the upper end by the fixed platen 112 and at the lower end by the machine frame 111, respectively. A pulley 129 fixed to the lower end of the ball screw shaft 128 is connected via a timing belt 132 by a pulley 131 fixed to an electric servo motor 130 disposed in the machine frame 111.

The injection device 103 includes a front support 170 to which a heating cylinder 161 is fixed, and a rear support 173 integrally formed on the front support 170 with a tie bar (not shown).
An injection frame portion 174, and a pressure plate 172 having a screw 162 rotatably attached to an intermediate portion of the injection frame portion 174.

The injection frame part 174 has two right and left parts standing on the upper surface of the movable platen 113 (a total of four
This is supported by a guide rod 171 in a vertically movable manner. Rear support 1
73 is provided with an injection driving device 165 (for forward and backward advancement and rotation of the screw 162).

On the upper surface of the movable platen 113, as shown in FIGS. 6 and 7, a pair of bearing cylinders 180 a and 180 b are located between the two left and right guide rods 171 a and 171 b, respectively. And a pair of ball screw shafts 181a, 1b extending between the left and right two guide rods 171a and 171b in parallel with each other.
A lower end 81b is supported in the bearing cylinders 180a and 180b so as to be rotatable about an axis.

The upper ends of the ball screw shafts 181a and 181b are inserted into holes that are vertically penetrated through the front support 170, and above the front support 170, bearing supports 183a fixed to the guide rods 171a and 171b, 183b (guide rod 17
1b is attached to the same position as 183a) and is supported by a bearing 184 so as to be rotatable in the circumferential direction.

Pulleys 190a and 190b are fixed near the upper portions of the bearing cylinders 180a and 180b, respectively. The pulleys 190 a and 190 b are interlocked by timing belts 192 a and 192 b that are individually provided around a pulley 191 that is fixed to an output shaft of a motor 193 with a speed reducer attached to the rear surface of the movable platen 113.
A ball nut 194 fixed to the front support 170 has a ball screw shaft 181a,
It is screwed with the ball screw part of the upper part of 181b.

When the electric servo motor 130 rotates and the ball screw shaft 128 rotates via the pulley 131, the timing belt 132, and the pulley 129, the cross head 126 moves upward or downward via the ball nut 127, and the toggle mechanism 116 is moved. Since it is expanded and contracted, the toggle support 115 is raised or lowered accordingly.
As a result, the movable platen 113 is raised or lowered, and the fixed mold 152 and the movable mold 151 are closed or opened.

When the motor 193 with a brake rotates, one ball screw shaft 181a passes through the pulley 191, the timing belt 192a, and the pulley 190a, and the other ball screw shaft 181b passes through the pulley 191, the timing belt 192b, and the pulley 190b. Each rotates in synchronization. When each ball screw shaft 181a, 181b rotates, each ball screw shaft 181a,
Front support 17 via ball nuts 194a, 194b screwed to 181b
0 falls or rises.

When the mold clamping device 102 completes the mold clamping and the nozzle portion at the tip of the heating cylinder 161 disposed in the injection device 103 comes into contact with the movable mold 151 and the nozzle touch is completed, the injection driving device 16
5, the molten resin previously measured at the front end portion in the heating cylinder 161 passes between the fixed mold 152 and the movable mold 151 through the nozzle by the forward movement of the screw 162 via the pressure plate 172. The formed cavity space is injection filled. When cooling and solidification of the molded product is completed after injection filling, the mold is opened and the molded product is taken out from the molding machine.

Japanese Patent Laid-Open No. 2002-172671

In a vertical injection molding machine, since the overall height of the molding machine is high, the lateral vibration of the injection device is easily amplified by mechanical vibration during molding.
Moreover, in order to cancel the bending moment applied to the movable platen due to the reaction force at the time of nozzle touch, which causes the mold clamping accuracy to deteriorate, four guides arranged facing each other in the same plane including the axis of the screw cylinder portion It is best to guide the injection device with a bar.
Therefore, the drive ball screw shaft for raising and lowering the injection device must be disposed at an intermediate position between the two left and right guide bars.

On the other hand, during the molding process, access around the nozzle is required to eliminate the molten resin leaking onto the mold and to clean it, but a drive ball for raising and lowering the injection device between the left and right guide rods Since the screw shaft is disposed, there is a problem that access from the left and right directions is hindered.

In addition, depending on the size and weight of the molded product to be molded, three types of screw cylinder portions having different lengths of a large diameter, a medium diameter, and a small diameter are generally replaced and mounted at the molding site.
Therefore, the screw range of the ball screw shaft required to raise and lower the injection device is the ascending limit when the longest large-diameter screw cylinder is installed and the descending limit when the shortest thin-screw cylinder is installed (nozzle touch). ) Is required to satisfy both of the above requirements. for that reason,
A thin and long ball screw shaft is required, and the processing of the ball screw shaft requires a processing time and is very expensive in order to maintain the processing accuracy.

Further, the two drive ball screw shafts for raising and lowering the injection device are driven synchronously via a timing belt by a motor with a brake attached to the movable platen portion.
When the ascending / descending operation is stopped, the braking force of the motor with brake locks the drive ball screw shaft via the timing belt. However, if the timing belt breaks, the braking force of the motor with brake does not act on the drive ball screw shaft, so the drive ball screw shaft rotates due to the weight of the injection device, and the injection device falls unsuccessfully and the mold is removed. It may be damaged.

An object of the present invention is to provide a vertical injection molding machine that solves the above-mentioned problems in a conventional vertical injection molding machine, improves maintenance and safety, and can be manufactured at low cost.

Therefore, in the vertical clamp injection type electric vertical injection molding machine of the present invention, at least the guide bar portion of the guide mechanism of the injection device where the drive ball screw shaft for raising and lowering the injection device is disposed has a hollow structure. Also, the drive ball screw shaft is disposed inside the hollow structure.

Further, the plurality of drive ball screw shafts for ascending and descending the injection device are arranged at equal distances diagonally in the same plane including the axis of the screw cylinder portion.
Further, a motor with a brake for the drive ball screw shaft for raising and lowering the injection device was directly connected to at least one of the drive ball screw shafts.

In addition, a length adjusting portion that absorbs and adjusts the difference in total length due to the mounting of screw cylinder portions having different total lengths is provided at the lower part of the guide bar in which the drive ball screw shaft is disposed.
Further, the length adjusting unit has a mechanism for preventing the guide bar from rotating, and a mechanism for locking the axial movement of the guide bar after the height adjustment is completed.

As described above, the drive ball screw shafts for raising and lowering the injection device are disposed equidistantly within the hollow structure of the hollow guide bar and diagonally within the same plane including the axis of the screw cylinder part. As a result, the maintainability of the screw cylinder portion around the nozzle has been greatly improved while preventing the bending moment applied to the movable platen due to the reaction force of the nozzle touch and maintaining high clamping accuracy.

In addition, since a motor with a brake for driving the ball screw is directly connected to at least one of the drive ball screw shafts for raising and lowering the injection device, the braking force of the drive motor can be applied directly to the ball screw shaft without using a timing belt or the like. Became possible. Therefore, even if the belt is broken, the accidental drop due to the dead weight of the injection device can be prevented, and the safety is improved.

In addition, a length adjustment mechanism is provided at the lower part of the guide bar, and this mechanism absorbs the difference in the total length of the screw cylinder parts with different lengths. The length of the ball screw that covers the range from the upper limit to the lower limit when the small-diameter screw cylinder is installed is unnecessary, and as a result, the ball screw shaft itself can be shortened, thereby shortening the processing time of the ball screw. However, the machining accuracy can be easily maintained, so that an inexpensive ball screw shaft can be used.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a front view of an injection apparatus embodying the present invention, FIG. 2 is a cross-sectional plan view of the injection apparatus taken along arrows A, B, and C in FIG. 1, FIG. 3 is a longitudinal sectional view of an ascending / descending drive unit, and FIG. It is a longitudinal cross-sectional view of a length adjustment part.

In FIG. 1 and FIG. 2, reference numeral 1 denotes an injection device of a vertical clamping injection type electric vertical injection molding machine in which a clamping device and an injection device are arranged in series in the vertical direction.
The injection device 1 includes a screw cylinder unit 25, an injection frame unit 20, an injection and metering drive unit 35, ascending / descending drive units 40a and 40b, and a motor 51 with a brake that constitutes a part of the ascending / descending drive unit 40a. And the upper frame 10 with the length adjustment portions 70a and 70b
And guide bars 9a and 9b for guiding the raising and lowering of the injection frame portion 20.

A movable mold 4 is formed on the lower surface of the upper end on the injection device side of four tie bars 3 (only two are shown) that constitute a part of the mold clamping device (only one part is shown). Attached movable platen 2
Are fixed, and on the upper surface of the movable platen 2, two hollow guide bars 9a and 9b are provided.
In the same plane including the axis of the screw cylinder part 25, the lower ends thereof are screwed into the movable platen 2 at an equal distance and arranged upward.

Further, the length adjusting portions 70a and 70b constituting the lower portions of the ascending / descending drive portions 40a and 40b are opposed to the guide bars 9a and 9b at equal distances diagonally within the same plane including the axis of the screw cylinder portion 25. In addition, the lower end of the guide bars 9a and 9b is screwed to the movable platen 2 at the same center distance, and the guide bars 9a and 9b are disposed upward.

The upper frame 10 is disposed above the ball screw shafts 41 and 42 constituting the ascending / descending drive units 40a and 40b via bearings.
In the vicinity of the bearing portion of the upper frame 10, two stud bolts 11 are disposed downward, and the lower end screw portion of the stud bolt 11 is a rear support 2 that constitutes the injection frame portion 20.
2 screwed.

The injection frame portion 20 includes a rear support 22 having an injection and metering drive portion 35 attached thereto, a front support 21 having a screw cylinder portion 25 attached downward on a lower surface thereof, and a tie rod having a small diameter portion formed with screw portions at both ends. 23a, 23b and the tie rod 23
The small-diameter portions a and 23b are fitted into the mounting holes of the front support 21 and the rear support 22, respectively, and then formed into an integral box structure by a nut 24 that is tightened to the screw portion.
The injection frame portion 20 having an integral box structure is suspended from the upper frame 10 by stud bolts 11.

The injection and metering drive 35 includes a ball nut 32 attached to the rear support 22.
The ball nut 32 is screwed into both ends, and both ends are attached to a spline-structured ball screw shaft 31 and a spline portion below the ball screw shaft 31, and driven by a metering drive motor (not shown) via a transmission mechanism. A measuring pulley 30, an injection pulley 33 attached to an upper spline portion of the ball screw shaft 31 and driven by a transmission mechanism from an injection drive motor (not shown), and a lower spline of the ball screw shaft 31. And a mechanism for connecting the screw 27 to the end face of the.

The screw cylinder unit 25 is a heating cylinder 26 having a heater (not shown) mounted on the outer periphery.
And a screw 27 that is rotatably and slidably incorporated therein, and a nozzle 28 that is attached to the front end of the heating cylinder 26 and injects and fills molten resin into the cavity space of the mold.

The heating cylinder 26 of the screw cylinder portion 25 is attached to the center of the lower surface of the front support 21, and the end of the screw 27 on the side opposite to the nozzle is joined to the end surface of the drive screw shaft 31 of the injection and metering drive portion. .

The front support 21 constituting the injection frame portion 20 is guided at four positions by guide bars 71a and 71b and guide bars 9a and 9b constituting a part of the length adjusting portions 70a and 70b, and the rear support 22 is a guide. Guided in two places, bars 9a and 9b.

A pulley 52 is attached to the upper part of the ball screw shaft 41 that constitutes a part of the ascending / descending drive unit 40a, and the ball screw shaft 41 is directly connected to the motor 51 with brake by a coupling 50 above the pulley 52. . A pulley 53 is attached to the upper end of the ball screw shaft 42 of the ascending / descending drive unit 40b disposed diagonally to the ascending / descending drive unit 40a, and a timing belt 54 is hung between the pulleys 52, 53. The pulleys 52 and 53 are driven synchronously.

The path of the timing belt 54 is guided by an idler pulley 55 disposed on the upper frame 10 and a tension pulley 56 disposed on a bracket 57 which is attached by a mounting bolt 58 and whose mounting position can be adjusted.

In FIG. 3, reference numeral 40a denotes an ascending / descending drive unit disposed on the front side of the molding machine.
71a is a guide bar formed hollow inside, the upper end portion on the side opposite to the nozzle is a large-diameter flange, a ball nut 43 is attached by a mounting bolt 44, and the outer diameter portion below it is a guide bar 9a. 9b, the front support 21 is guided at four locations together with the guide bars 9a, 9b.

The ball nut 43 is screwed with the ball screw shaft 41. A stopper 45 is fixed to the lower end on the nozzle side of the ball screw shaft 41 by a mounting bolt 46, and is inserted into the hollow portion of the guide bar 71a so as to be able to rotate and advance and retract.

The upper portion of the ball screw shaft 41 on the side opposite to the nozzle is formed with a three-stage narrow diameter portion, and the upper frame 10
The rear supports 22 are arranged through holes that penetrate vertically.
A bearing 16 which is inserted into the enlarged diameter portion of the hole of the upper frame 10 and whose outer diameter is prevented from coming off by the flange 15 is attached. The first-stage narrow diameter portion of the ball screw shaft 41 is passed through the bearing 16. ing. A pulley 52 is attached to the second stage of the narrow diameter part, and a coupling 50 is attached to the third stage of the uppermost part, and is directly connected to a motor 51 with a brake attached to the upper frame 10.
The pulley 52 is a timing belt 54 and the ascending / descending drive unit 4 disposed at the rear side of the molding machine.
The pulley 53 is connected to the upper end of the ball screw shaft 42 of 0b.

In the vicinity of the bearing 16 mounting portion of the upper frame 10, two bolt mounting holes are vertically penetrated and stud bolts 11 having small threaded portions at both ends are inserted therein. The small-diameter threaded portion is fixed with a nut 13 after a washer 12 is mounted from the upper surface of the upper frame 10.

On the other hand, the lower small diameter thread portion is fastened to the rear support 22. A spring 14 surrounding the stud bolt 11 is attached between the lower surface of the upper frame 10 and the upper surface of the rear support 22.

In FIG. 4, 70a is a length adjusting unit. The guide support 75a has a hollow structure, and the inner diameter portion thereof guides the outer diameter of the thread portion of the guide bar 71a so as to be slidable in the axial direction. Further, the upper and lower surfaces of the guide bar support 75a have a flange structure, the lower flange portion is fixed to the movable platen 2 by a mounting bolt 76, and the upper flange portion is a screw that meshes with the threaded portion by the mounting bolt 72. A fixing nut 7 formed on the inner periphery
3 is fixed.

Between the fixed nut 73 and the flange portion on the upper surface of the guide support 75a, a support nut 74 in which a screw meshing with the screw portion is formed on the inner periphery is disposed with a gap left in the axial direction.

A slide key 78 is attached below the guide bar 71a so as to protrude in the axial direction and in the radial direction. The sliding key 7 is provided on the inner surface of the body portion of the guide support 75a.
A key sliding long hole groove 77 that restricts the rotation of the eight protrusions and allows only sliding is machined.

Next, the operation of the present invention will be described.
When the mold is fully closed and the weighing is completed, the brake motor 51 starts to rotate. This rotation is caused by the ascending / descending drive units 40a and 40b via the coupling 50 and the timing belt 54.
The pulleys 52 and 53 are rotated, and the ball screw shafts 41 and 42 are further rotated.

Since the ball nuts 43 fixed to the guide bars 71a and 71b whose vertical movement is restricted are screwed onto the ball screw shafts 41 and 42, the ball screw shafts 41 and 42 are connected to the guide bar 71.
a, 71b while rotating inside. Thereby, the ascending / descending drive unit 40
The total length of a and 40b can be shortened, and as a result, the overall height of the injection molding machine can be reduced.

The movements of the ball screw shafts 41 and 42 are transmitted to the upper frame 10, the stud bolt 11, the rear support 22, the front support 21, and the screw cylinder part 25 via the bearing 16, and finally the tip of the screw cylinder part 25. The nozzle 28 is touched to the movable mold 4.

The injection frame portion 20 to which the upper frame 10 and the screw cylinder portion 25 are attached.
A spring 14 is mounted between the rear supports 22 constituting the upper frame 10.
On the other hand, the screw cylinder part 25 can be relatively moved only in a certain range in the vertical direction.

When the tip of the nozzle 28 comes into contact with the mold 4, the lowering of the rear support 22 stops.
However, the motor with brake 51 continues to rotate, and the upper frame 10 continues to descend while compressing the spring 14 to generate a pressing force at the tip of the nozzle 28. When the spring 14 bends by a predetermined distance, it is determined that a predetermined amount of nozzle touch force is generated by a bend amount detecting means such as a proximity switch, and the rotation of the motor 51 with brake is stopped.

The brake-equipped motor 51 maintains the rotation angle by applying a braking force provided in the motor at the same time that no current flows to the motor. As a result, the nozzle touch force is also maintained. Next, when injection filling is performed and the cooling of the molten resin in the mold cavity is completed, the brake force is released and the brake motor 51 rotates in the reverse direction, so that the screw cylinder part 2
5 starts to rise.

A stopper 45 is attached to the lower ends of the ball screw shafts 41 and 42, and does not go beyond the stroke assumed when the nozzle 28 is pulled away from the movable mold 4 by contacting the end of the ball nut 43. It regulates so that.

Since the motor 51 with brake and the ball screw shaft 41 are directly connected, the ascending / descending drive unit 4
Even if the timing belt 54 connected to the 0b side is cut off, the ball screw shaft 41 remains applied with the braking force, and the screw cylinder portion 25 does not fall unintentionally due to its own weight.

When the screw cylinder part 25 is exchanged from the longest large diameter to the shortest thin diameter, the distance from the tip of the nozzle 28 to the movable mold 4 is increased by the difference in the total length of the screw cylinder part 25 as it is. The distance between the nozzle 28 and the movable mold 4 is adjusted by the length adjusting unit so that it is substantially the same regardless of which screw cylinder unit is mounted.

With the mounting bolt 72 removed, the support nut 74 is rotated to move the guide bar 71a downward within the guide bar support 75a, so that the nozzle position of the small diameter cylinder is substantially the same as the nozzle position of the large diameter cylinder. Adjust the position so that

Thereafter, the attachment bolt 72 is attached while leaving a gap between the fixing nut 73 and the support nut 74. Also, with this method, the length can be adjusted only by adjusting the currently attached component without replacing another component for adjusting the length, so that the operation is easy and the safety is high.

The configuration of the present invention is as described above, and the four ball screw shafts that obstruct access to the periphery of the nozzle are mounted in a hollow guide bar, thereby minimizing the lateral deflection of the injection device. The accessibility was improved while retaining the guide function. In addition, by installing a length adjustment unit that can absorb the difference in the length of the screw cylinder from the large diameter to the small diameter, the ball screw shaft that is expensive and difficult to process can be minimized, and at the same time, the length can be adjusted. Since there is no work to replace with other adjustment parts on site, a vertical injection molding machine of the vertical vertical injection system that is easy to work and high in safety can be provided.
In addition, this invention is not limited to the form of the said Example, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

Front view of an injection apparatus embodying the present invention 1 is a cross-sectional plan view of the injection device as viewed from arrows A, B, and C in FIG. Vertical sectional view of the ascending / descending drive Longitudinal section of length adjustment section Front view of conventional vertical injection molding machine Side view of the ascending / descending drive unit of the injection device 6 is a cross-sectional plan view of the injection device as viewed from the direction of arrow D in FIG.

Explanation of symbols

2 movable platen 52 pulley 10 upper frame 53 pulley 20 injection frame part 54 timing belt 21 front support 70a length adjustment part
22 rear support 71a guide bar 25 screw cylinder part 73 fixing nut 35 injection and metering drive part 74 support nut 40a ascending / descending drive part 75a guide bar support 41 ball screw shaft 43 ball nut 51 motor with brake

Claims (5)

In a vertical clamp injection type electric vertical injection molding machine, at least a guide bar portion of a guide mechanism of an injection device of the injection molding machine in which a drive screw shaft for raising and lowering the injection device is disposed has a hollow structure. An electric vertical injection molding machine in which the drive screw shaft is disposed inside the hollow structure. The electric vertical injection molding machine according to claim 1, wherein the plurality of drive screw shafts for raising and lowering the injection device are arranged diagonally within the same plane including the axis of the screw cylinder portion. The electric saddle type injection molding machine according to claim 1, wherein the drive screw shaft drive motor for driving and lowering the injection device is directly connected to at least one of the drive screw shafts. . In a vertical clamping injection type electric vertical injection molding machine, a length adjusting part that absorbs and adjusts the difference in the overall length of the screw cylinder part due to the mounting of a screw cylinder part having a different diameter is arranged inside the drive screw shaft. An electric vertical injection molding machine provided at the lower part of the provided guide bar. 5. The electric motor according to claim 4, wherein the length adjusting unit has a mechanism for preventing the rotation of the guide bar, and further has a mechanism for locking the movement of the guide bar in the axial direction after the length adjustment is completed. Vertical injection molding machine.

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