JP2000190361A - Electric injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a quiet operation and reduce generation of abrasion powder of a belt by rotatably pivotting a rotatable and a freely advanceable/ retreatable screw in a heating cylinder, and housing a mechanism to transmit the rotational force of a measuring motor in a space in the interior of a pressure plate for advancing and retracting by a ball screw. SOLUTION: A hollow 38 houses toothed gears 23, 24, 25 with a hollow shaft 18, a bearing holder 17, a pressure plate 11 and bracket 13, and a motor flange 14. An oil feeding port for feeding oil to the hollow 38 at the upper part of the pressure plate 11 forming the hollow 38, and an oil discharge port at the lower part thereof. At a measuring process, when a measuring motor 8 is driven, rotational force is transmitted from an output shaft 8a to the toothed gears 23, 24, 25, and rotational force via a bearing box 16 is transmitted to a screw shaft 3 through the rotation of a annular toothed gear 25. This constitution allows a noise insulation effect and quiet operation by holding lubrication oil within the hollow 38, resulting in preventing the occurrence of abrasion powder in an injection part or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric injection molding machine. Particularly, the present invention relates to a rotation transmission mechanism of a screw shaft in an electric injection molding machine.

[0002]

2. Description of the Related Art In an injection molding machine, a resin heated and melted in a heating cylinder is injected at a high pressure, filled into a cavity space in a mold apparatus, and cooled and solidified in the cavity space to form a molded product. You can get it.

Such an injection molding machine has a mold clamping device and an injection device. The mold clamping device has a fixed platen and a movable platen. The mold closing cylinder advances and retreats the movable platen to close, close, and clamp the mold. The mold can be opened.

On the other hand, the injection device is provided with a heating cylinder for heating and melting the resin supplied from the hopper and an injection nozzle for injecting the molten resin, and a screw is rotatable in the heating cylinder and movable back and forth. It is arranged in. Then, the screw is moved forward, the resin is injected from the injection nozzle, and the screw is moved backward to measure the resin.

[0005] An injection device of an electric injection molding machine using an electric motor for moving the screw forward and backward has been provided. Hereinafter, three prior arts will be described with reference to FIGS. (Prior Art) FIG. 7 is a schematic view of an injection device of a conventional electric injection molding machine. In FIG. 7, 101 is an injection device, 10
Reference numeral 2 denotes an injection device frame. Injection device frame 102
A heating cylinder 104 is fixed in front of the nozzle, and an injection nozzle 103 is provided at a front end of the heating cylinder 104.
A hopper 105 is provided in the heating cylinder 104. A screw 106 is provided in the heating cylinder 104.
Are provided so as to be able to advance and retreat and rotate freely.
6 is rotatably supported by a support member 107.

A weighing motor 108 having a speed reduction mechanism is attached to the support member 107.
Rotation of the screw 1 via the timing belt 109
06. A screw shaft 111 is rotatably supported in parallel with the screw 106, and the screw shaft 1
An injection motor 113 with a speed reduction mechanism is connected to the rear end of the motor 11 via a timing belt 112 so that the screw shaft 111 can be rotated by the injection motor 113. A nut 114 fixed to the support member 107 is screwed to the front end of the screw shaft 111.
Therefore, by driving the injection motor 113 and rotating the screw shaft 111 via the timing belt 112, the nut 114 can be moved in the axial direction.

In the injection device 101 having the above-described configuration, when the measuring motor 108 is driven and the screw 106 is rotated via the timing belt 109 during the measuring process,
Resin is supplied from the hopper 105 and the heating cylinder 104
Inside, the resin is heated and melted. The screw 1
With the rotation of 06, the resin accumulates in front of the screw 106, and the screw 106 moves backward (moves rightward in the figure).

In the injection step, the injection motor 11
3 and the screw shaft 1 via the timing belt 112.
11 is rotated. At this time, the nut 114 and the support member 107 move with the rotation of the screw shaft 111 and advance the screw 106, so that the resin accumulated in front of the screw 106 is injected from the injection nozzle 103 toward the cavity.

Next, the invention filed by the present applicant as a Japanese Patent Application No. 9-308662 on November 11, 1997 (hereinafter referred to as "the prior invention") will be described with reference to FIG. . In FIG. 8, reference numeral 150 denotes a heating cylinder.
The point 1 is provided so as to be able to advance and retreat and to be rotatable as in the conventional one. The screw 151 has a screw head at the front end and the heating cylinder 1
50 extends rearward, and a bearing box 153 is provided at the rear end.
Has been fixed. A spiral flight 154 is formed around the screw 151, and a groove is formed between the flights 154.

A hopper is fixed to the heating cylinder 150 (not shown). The resin supply port from the hopper is formed at a position corresponding to the rear end of the screw groove when the screw 151 is placed at the forefront in the heating cylinder 150. Therefore, when the screw 151 is rotated during the measuring process, the resin in the form of pellets is supplied from the inside of the hopper, and the resin enters the heating cylinder 150 and is advanced in the groove of the screw.

A heater (not shown) is provided around the heating cylinder 150, and the heating cylinder 150 is heated by the heater to melt the resin in the screw groove.
Therefore, when the screw 151 is rotated, the screw 151 retreats due to the resin pressure, and one shot of the melted resin accumulates in front of the screw head.

Next, during the injection step, the screw 151
When the is advanced without rotating, the resin accumulated in front of the screw head is injected from the injection nozzle 152 and is filled in the cavity space of the mold. A driving unit 155 for rotating or moving the screw 151 forward or backward is provided behind the heating cylinder 150. Drive unit 1
55 includes a metering motor 157 movably disposed with respect to the frame 156 and an injection motor 158 fixed to the frame 156. The injection motor 158 and the screw 151 are disposed on the same axis. I have.

A guide bar 159 extending in parallel with the screw 151 is provided on the frame 156.
The weighing motor 157 moves along 9. For this purpose, a support plate 160 is slidably disposed with respect to the guide bar 159, and a weighing motor 157 is attached to the support plate 160. A driving pulley 161 is fixed to the output shaft of the weighing motor 157, and a driven pulley 163 is fixed to the outer periphery of the box body 162 of the bearing box 153. The driving pulley 161 and the conventional pulley 163 are fixed.
A timing belt 164 is stretched between them. The drive box pulley 161, the driven pulley 163, and the timing belt 164 form the bearing box 15
Transmission means for connecting the motor 3 and the weighing motor 157 is configured.

On the other hand, the injection motor 158
The rotor 166 is rotatably supported by a frame 156. The stator 165 is fixed to the stator 165 and the rotor 166 is disposed on the inner peripheral side of the stator 165. For this purpose, a hollow rotor shaft 167 is fitted into and fixed to the rotor 166, and both ends of the rotor shaft 167 are supported by bearings 168 and 169 in the frame 156.
It is supported by.

Further, bearings 170 and 171 are provided in the bearing box 153, and the screw 151 and a ball screw shaft 172 as a transmission shaft are relatively rotatably connected by these bearings.
Nut 173 fixed to the vehicle via a load cell 177
And a screw portion 174 formed on the ball screw shaft 172 are screwed together. The rotational movement is converted to a linear movement by the screw portion 174 of the ball screw shaft.

Therefore, in the measuring step, when the measuring motor 157 is driven, the rotation of the measuring motor 157 is sequentially transmitted to the driving pulley 161, the timing belt 164, the box body 162 and the screw 151, and the screw 151 rotates. The resin moves to the front of the screw head. In this case, since the screw 151 and the ball screw shaft 172 are relatively rotatably connected via the bearing box 153, the rotation transmitted to the box main body 162 is not transmitted to the ball screw shaft 172, but the heating cylinder 150 The pressure of the resin inside is transmitted to the ball screw shaft 172 via the bearing box 153. Therefore, the ball screw shaft 172 moves backward while rotating, and accordingly, the screw 151 moves backward. When the screw 151 is retracted, a back pressure is applied to the screw 151 against the pressure of the resin.

On the other hand, in the injection motor 158, by supplying a current of a predetermined frequency to the stator 165, the screw 151 can be advanced without rotating. Therefore, the hollow rotor shaft 16
7, an annular locking member 175 is fixed, and a spline 176 formed on the inner circumference of the locking member 175 and a spline formed on the outer circumference of the rear part of the ball screw shaft 172 are engaged. The spline 176 forms a rotation transmitting unit that transmits the rotation of the injection motor 158.

Therefore, in the injection step, when the injection motor 158 is driven, the rotation of the injection motor rotates the rotor shaft 167, the locking member 175 and the ball screw shaft 17.
2 sequentially. Since the ball nut 173 is fixed to the frame 156, the ball screw shaft 17
2 rotates and advances, and advances the screw 151. At this time, the radiation output applied to the timing belt 164 is transmitted to the load meter 177 via the bearing box 153 and detected. The ball screw shaft 172 moves forward and backward by a stroke S in the axial direction.
(FIG. 8).

As described above, the rotation of the injection motor 158 is performed without the intervention of the speed reduction mechanism, the pulley, or the like.
2, the mechanical efficiency can be increased and the inertia can be reduced.

Since the locking member 175 is disposed substantially at the center of the rotor shaft 167, when the screw 151 is placed at the rear end position, the spline 17
6 can be placed inside the right end of the rotor shaft 167. Therefore, the spline 176 is connected to the rotor 1
66, that is, in the rotor shaft 167, and the axial dimension of the built-in motor type injection device can be reduced.

[0021]

As described above, according to the configuration of the prior invention by the present applicant described with reference to FIG.
The rotor 166 of the motor 158 for injection is splined.
, That is, in the rotor shaft 167, the axial dimension of the built-in motor type injection molding machine can be reduced. However, as apparent from FIG. 8, the timing belt 164 for transmitting the output of the weighing motor is used.
Is exposed. The timing belt 109 is also exposed in the prior art shown in FIG. The present invention reduces the noise at the time of screw rotation caused by such a structure, and provides an injection molding machine with a quiet operation, generation of abrasion powder of a belt caused by driving by a timing belt, and management of a belt life. It is an object of the present invention to provide an injection molding machine capable of minimizing maintenance work for the injection molding. In particular, it is an object of the present invention to improve the drive unit of a heating device of an injection molding machine to achieve the above object.

[0022]

Means for Solving the Problems A heating cylinder, a screw disposed in the heating cylinder so as to rotate and move forward and backward, and a pressure plate that rotatably supports the screw and moves forward and backward by a ball screw, The pressure plate has a cavity formed therein, and accommodates a rotation transmitting mechanism for transmitting the rotational force of the metering motor to the screw in the cavity. In the above configuration, the rotation transmission mechanism is constituted by a gear train. In the above configuration, the lubricating oil is held in the hollow portion, and the replenishment and withdrawal of the lubricating oil are enabled.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given with reference to FIGS. The basic technical idea that the present invention is an electric injection molding machine is an extension of the electric injection molding machine according to the prior invention described with reference to FIG. However, the present invention is characterized in that the rotation transmitting means is provided in the hollow portion in order to further improve this and reduce noise when the screw rotates.

FIG. 1 is a cross-sectional view of an injection molding machine according to the present invention, and FIG. 2 is an external side view of the injection molding machine according to the present invention. FIG. 3 is a sectional view taken along the arrow A in FIG. 4 is a sectional view taken along the arrow C of FIG. 1, FIG. 5 is a sectional view taken along the arrow D of FIG. 1, and FIG. 6 is a sectional view taken along the arrow E of FIG. 1 and 2, 1
Denotes a heating cylinder.
Similar to the prior art described below, a screw (see FIG. 7) is provided so as to be able to advance and retreat and rotate freely.
The screw and the screw shaft 3 extend rearward in the heating cylinder 1, and the rear end of the screw shaft 3 is fixed to a screw support plate 4 (see FIG. 6).

A resin supply port 5 is formed at a set location in the heating cylinder 1 as in the case shown in FIG. 7 and below, and a hopper (FIG. 2) is fixed on the resin supply port 5. The resin supply port 5 is formed at a position corresponding to the last end of a groove formed by flight of the screw when the screw is placed at the forefront in the heating cylinder 1. Therefore, when the screw shaft 3 is retracted while rotating during the measuring step, pellet-shaped resin is supplied from the resin supply port 5.

A heater (not shown) is provided around the heating cylinder 1, thereby heating the heating cylinder 1 and melting the resin in the groove of the screw 2. Therefore, when the screw 2 is rotated, the screw 2 retreats due to the resin pressure, and one shot of molten resin accumulates in front of the screw head.

Next, when the screw shaft 3 is advanced without rotating during the injection step, the molten resin accumulated in front of the screw head is injected from the injection nozzle and filled in the cavity space in the mold. .

By the way, behind the heating cylinder 1, there is a drive unit 6 for rotating and moving the screw 2 forward and backward. The drive unit 6 includes a weighing motor 8 movably disposed with respect to the machine frame 7 and an injection motor 9 fixed to the machine frame 7, and the injection motor 9 and the screw shaft 3 are coaxial. It is arranged on the line.

A plurality of guide rods 10 extending in parallel with the screw 2 are provided on the machine frame 7 (FIG. 4). A pressure plate 11 supporting the measuring motor 8 moves along the guide rods 10. . As shown in FIGS. 1 and 2, the machine frame 7 includes a front frame 7 a that covers the heating cylinder 1 and a ball nut 3 that will be described later.
6 and a rear frame 7b supporting the guide rod 10. These front and rear frames 7a and 7b are integrally connected by four connecting rods 12 as shown in FIG.

A bracket 13 (FIGS. 1 and 3) for mounting a motor is mounted on the side of the pressure plate 11, and a weighing motor 8 is mounted on the bracket 13 via a motor flange 14. A bearing box 16 is rotatably mounted in the pressure plate 11 via bearings 15a and 15b. 17
Is a bearing holder, which holds one bearing 15b. The bearing box 16 includes an annular hollow shaft 18 fixed to the rear of the screw support plate 4 and a bearing retainer 19. The front end of the ball screw shaft 30 is rotatably supported via bearings 20 and 21. Numeral 22 denotes a bearing holder, which allows the bearing 20 to hold the bearing holder 1
9 is held.

The output shaft 8a of the measuring motor 8 in FIG.
Gear 23 is fixed to the intermediate gear 24.
Through the ring gear 25. Ring gear 25
Is fixed to the outer periphery of the hollow shaft 18, and one end of the hollow shaft 18 is bolted to the rear end of the screw support plate 4. 38 is a hollow shaft 18, a bearing holder 17,
The pressure plate 11, the bracket 13, and the motor flange 14 are hollow portions for housing the gears 23, 24, and 25.

The injection motor 9 has a stator and a rotor. A hollow rotor shaft 26 is fitted and fixed to the rotor. Both ends of the hollow rotor shaft 26 are bearings 27,
At 28, a spline nut 29 is rotatably supported within the motor frame, and a spline nut 29 is fixed within the hollow rotor shaft 26.
A spline shaft 31 fixed to the rear end of the ball screw shaft 30 is slidably engaged with the spline nut 29.
The forward / backward movement of the spline shaft 31 is restricted by a backward limit stopper 32 and a forward limit stopper 33.

Reference numeral 34 denotes a guide rod support member for supporting the rear end of the guide rod 10, to which the injection motor 9 is fixed. 35 is a rear frame 7b and a ball nut 3
A fuel cell plate 37 having a fuel supply port is fixed to a rear portion of the load cell 35 by a load cell fixed to a flange 36a provided at the rear end of the load cell 35. Eventually, the guide rod 10 penetrates the rear frame 7b, and is supported by the guide rod support member 34 by being tightened with the screw 10a.

As shown in FIG. 5, an oil supply port 39 for supplying oil into the cavity 38 is formed at an upper portion of the pressure plate 11 forming the cavity 38, and a pressure plate is formed. A discharge port 40 for discharging the oil from the cavity 38 is formed in a lower portion of 11. A plug 41 is attached to the fuel supply port 39 and the discharge port 40.

With the above configuration, in the measuring step,
When the weighing motor 8 is driven, its rotation is transmitted from the output shaft 8a to the gears 23, 24, and 25, and the rotation of the ring gear 25 rotates the bearing box 16. The bearing box 16 is composed of the bearings 20 and 21 and the ball screw shaft 3.
This rotation is transmitted to the screw shaft 3 via the screw support plate 4 because it is freely rotatable with respect to 0. In the present invention, the rotation transmission mechanism is constituted by a gear train. However, as in the conventional example, a drive system using a timing belt (for example, by removing the intermediate gear 24 and setting the timing belts on the gears 23 and 25) may be used. By providing in the hollow portion, an effect equivalent to the present invention can be exerted, and does not deviate from the gist of the present invention.

In the injection step, the hollow rotor shaft 26 is rotated by the rotation of the injection motor 9 and the spline shaft 3 is rotated.
Then, the ball screw shaft 30 fixed at the front end of the spline shaft 31 is further rotated. Then ball nut 3
6, the ball screw shaft 30 is advanced, and the screw shaft 3
Is advanced to perform injection.

[0037]

According to the construction described above, the transmission mechanism for transmitting the rotation of the weighing motor 8 is formed in the cavity provided in the pressure plate 11, and the cavity is provided outside the cavity. Is completely covered and is isolated from the outside air, so that it is possible to retain the lubricating oil in the cavity together with the noise and sound insulation effect generated by the transmission mechanism. In addition, since the driving is performed by the gear train, extremely quiet operation is possible. Even if a timing belt, a chain, or the like is used, since it is housed in the hollow portion, it is quiet and does not generate abrasion powder at the injection portion or the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an injection molding machine embodying the present invention.

FIG. 2 is an external side view of the same.

FIG. 3 is an A sectional view of FIG. 1;

FIG. 4 is a sectional view taken along the line C in FIG. 1;

FIG. 5 is a sectional view taken along the line D in FIG. 1;

FIG. 6 is a sectional view taken along the line E in FIG. 1;

FIG. 7 shows a known molding machine.

FIG. 8 shows a “prior invention” by the present applicant in the same electric injection molding machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heating cylinder 2 Screw 3 Screw shaft 4 Screw support plate 5 Resin supply port 6 Drive unit 7 Machine frame 7a Front frame 7b Rear frame 8 Metering motor 9 Injection motor 10 Guide rod 11 Pressure plate 12 Connecting rod 13 Motor mounting Bracket 14 Motor flange 15a, 15b Bearing 16 Bearing box 17 Bearing holder 18 Hollow shaft 19 Bearing retainer 20 Bearing 21 Bearing 22 Bearing retainer 23 Gear 24 Intermediate gear 25 Ring gear 26 Rotor shaft 27 Bearing 28 Bearing 29 Spline nut 30 Ball screw shaft 31 Spline shaft 32 Backward limit stopper 33 Forward limit stopper 34 Guide rod support member 35 Load cell 36 Ball nut 37 Oil supply plate 38 Cavity 39 Oil supply port 40 Discharge port 41 Plug

Claims (3)

[Claims] 1. A heating cylinder, a screw disposed in the heating cylinder so as to rotate and move forward and backward, and a pressure plate rotatably supporting the screw and moving forward and backward by a ball screw, the pressure plate includes: An electric injection molding machine, wherein a hollow portion is formed therein, and a rotation transmitting mechanism for transmitting a rotational force of a metering motor to a front screw is housed in the hollow portion. 2. The rotation transmitting mechanism comprises a gear train.
The electric injection molding machine as described. 3. The electric injection molding machine according to claim 2, wherein lubricating oil is held in the cavity, and replenishment of the lubricating oil into the cavity and extraction from the cavity are enabled.