JP2000108181A - Foreign matter entrance preventing apparatus for motor driven injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid occurrence of an abnormal wear or scuffing of a frictionally sliding part and to prevent a decrease in durability by connecting a screw to a rotor rotating by a hollow motor, and preventing an entrance of a foreign matter into a slide to be frictionally slid by the rotor. SOLUTION: In the case of transmitting a rotation of a metering motor to a screw 22 with a first spline shaft 63 and advancing or retracting the screw 22 in a heating cylinder, when resin powder exhausted from a rear end of the screw 22 is introduced into a frictionally sliding part such as an engaging part of a first spline unit of a bearing 51, a wear or a scuff occurs. A sealing member 91 of a foreign matter entrance preventing member is mounted at an outer peripheral edge of a flange 18a of a front end of a sleeve 18 of a forward inner periphery of a first rotor shaft 56 to prevent an entrance of the matter together with a sealing member 92 arranged on an outer peripheral edge of a first coupling 81 of a front end of the shaft 63. Thus, an abnormal wear or a scuff of the sliding part is prevented to avoid a decrease in durability in the molding machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foreign matter entry device for an electric injection molding machine.

[0002]

2. Description of the Related Art Conventionally, 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 of a mold, and cooled in the cavity space. After solidification, the mold is opened and the molded product is taken out.

The injection molding machine has a mold clamping device and an injection device. The mold clamping device has a fixed platen and a movable platen, and opens and closes the mold by moving the movable platen forward and backward by a mold clamping cylinder. It has become. On the other hand, the injection device includes a heating cylinder for heating and melting the resin supplied from the hopper, and an injection nozzle for injecting the melted resin, and a screw is disposed in the heating cylinder so as to be able to move forward and backward.

In a hydraulic injection molding machine, a screw can be advanced by an injection cylinder to inject resin, and the screw can be metered by retracting the resin. On the other hand, in an electric injection molding machine, that is, a variable injection molding machine, an injection motor and a metering motor are provided in an injection device. In the measuring step, the rotation generated by driving the measuring motor is transmitted to the screw via the rotor shaft to rotate the screw. In the injection step, the rotation generated by driving the injection motor is transmitted to the rotor shaft, and the rotational motion of the rotor shaft is converted into linear motion by a ball screw, and the linear motion is transmitted to the screw. Then, the screw is advanced. In addition, a spline unit including a spline shaft and a spline nut is provided so as to transmit rotation from the weighing motor and linear motion from the ball screw.

[0005]

However, in the conventional injection molding machine, when the screw is advanced and retracted in the heating cylinder, resin powder may be discharged from the rear end of the screw. Therefore, in the case of a hydraulic injection molding machine, a foreign substance such as a resin powder is prevented from entering from outside by arranging a dust seal material in a packing row of an injection cylinder. Further, in the case of the variable injection molding machine, the foreign matter may be in a bearing that rotatably supports the rotor shaft, in a screw joint of a ball screw,
When the frictional sliding portion moves inside the engaging portion of the spline unit or the like, the frictional sliding portion is abnormally worn or gallinged, thereby lowering the durability of the injection molding machine.

The present invention solves the above-mentioned problems of the conventional injection molding machine and reduces the durability of the electric injection molding machine without causing abnormal wear or galling of the friction sliding portion. It is an object of the present invention to provide a foreign matter entry device for an electric injection molding machine that does not cause the foreign matter to enter.

[0007]

In order to achieve the object, in the foreign matter entry device of the electric injection molding machine according to the present invention, a hollow motor, a rotating body driven by driving the hollow motor, and a connection to the rotating body are provided. And a friction sliding portion that frictionally slides with the rotation of the rotating body, and a foreign matter entry preventing member that prevents foreign matter from entering the friction sliding portion.

In another aspect of the present invention, the rotating body is a rotor shaft, and the friction sliding portion is a bearing that rotatably supports the rotor shaft. In a further foreign matter entry device for an electric injection molding machine according to the present invention, the rotating body is a sleeve, the friction sliding portion is connected to the spline nut fixed to the sleeve, and the spline nut. Consists of a spline shaft.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a main part of a drive unit of an electric injection molding machine according to an embodiment of the present invention, FIG. 2 is a conceptual diagram of an injection device according to an embodiment of the present invention, and FIG. It is sectional drawing of the drive part of an injection molding machine.

In FIG. 2, reference numeral 12 denotes a heating cylinder. The heating cylinder 12 has an injection nozzle 12a at a front end (left end in the figure). A screw 22 is provided in the heating cylinder 12 so as to be able to advance and retreat and rotate freely. The screw 22 has a screw head 22a at the front end, extends rearward (to the right in the drawing) in the heating cylinder 12, and is connected at the rear end to a driving unit described later. A spiral flight 23 is formed around the screw 22, and the flight 23 forms a groove 26.

A resin supply port 29 is formed at a set place in the heating cylinder 12, and a hopper 30 is fixed to the resin supply port 29. The resin supply port 2
9 is formed at a position corresponding to the rear end of the groove 26 in a state where the screw 22 is located at the forefront (left side in the figure) in the heating cylinder 12.
Therefore, at the time of the measuring step, when the driving unit is driven to retract while rotating the screw 22, the pellet-shaped resin 33 in the hopper 30 falls and enters the heating cylinder 12, and Can be advanced.

A heater (not shown) is provided around the heating cylinder 12 so that the heating cylinder 12 can be heated by the heater and the resin 33 in the groove 26 can be melted. Therefore, when the screw 22 is retracted by a predetermined amount while rotating,
One shot of the melted resin 33 is stored in front of the screw head 22a.

Next, in the injection step, when the driving unit is driven to advance the screw 22 without rotating, the resin 33 stored in front of the screw head 22a is injected from the injection nozzle 12a. The cavity space of a mold (not shown) is filled. Next, the driving unit will be described.

In FIG. 3, reference numeral 11 denotes a drive unit case surrounding the drive unit, and the drive unit case 11 is fixed to the rear end of the heating cylinder 12 (FIG. 2). The drive unit case 1
1 includes a front cover 13, a center frame 15, a rear cover 17, a front frame 41 connecting the front cover 13 and the center frame 15, and a rear frame 42 connecting the center frame 15 and the rear cover 17. The front cover 13 and the front frame 41 are bolted together, the front frame 41 and the center frame 15 are bolted together, and the center frame 15 and the rear frame 42 are bolted together. 17 are fixed to each other by bolts b4.

A metering motor 44 as a hollow motor is provided at a front portion of the drive unit case 11, and an injection motor 45 as a hollow motor is provided at the rear portion on the same axis. The weighing motor 44 includes a stator 46 fixed to the front frame 41,
The injection motor 45 includes a stator 48 fixed to the rear frame 42, and an annular rotor 49 disposed on the inner peripheral side of the stator 48. Consists of

The rotor 47 is connected to the drive unit case 11.
Is rotatably supported with respect to. Therefore, the rotor 4
7 includes a hollow first rotor shaft 5 as a rotating body.
6 is fitted and fixed. The front end of the first rotor shaft 56 is supported by the front frame 41 by a bearing 51, and the rear end is supported by the center frame 15 by a bearing 52.

On the other hand, the rotor 49 is also connected to the drive unit case 11.
Is rotatably supported with respect to. Therefore, the rotor 4
9 has a hollow second rotor shaft 5 as a rotating body.
7 is fitted and fixed. The second rotor shaft 5
7 has a bearing 53 on the center frame 15 by a bearing 53 and a rear end by a bearing 54 on the rear frame 4.
2 supported.

In the measuring motor 44, by supplying a current of a predetermined frequency to the stator 46, the screw 22 can be moved backward while rotating. For this purpose, a sleeve 18 as a rotating body is disposed on the inner periphery of the front part of the first rotor shaft 56, and the front end of the sleeve 18 and the front end of the first rotor shaft 56 are fixed to each other by bolts b5. Is done. Further, a first spline nut 62 is fixed to a rear end of the sleeve 18 by a bolt b12, and the first spline nut 62 and the first spline shaft 63 are spline-connected. The screw 22 is fixed. In this case, the first spline nut 62 and the first spline shaft 63 constitute a first spline unit, a first driving force transmitting means, and a friction sliding portion, and rotate on the screw 22 and the first rotor shaft 56. The relative movement in the direction is constrained and the relative movement in the axial direction is allowed. The first spline shaft 63 has a length corresponding to the stroke of the screw 22.

Therefore, when the metering motor 44 is driven to rotate the rotor 47, the rotation of the rotor 47 becomes
The power is transmitted to the screw 22 via the first rotor shaft 56, the sleeve 18, the first spline nut 62, and the first spline shaft 63, and the screw 22 is rotated. Then, the resin 33 advances in the groove 26 while being melted, and the screw 22 is moved backward by the back pressure generated as the resin 33 advances.

At this time, the first spline nut 62
Since the first spline shaft 63 and the first spline shaft 63 are spline-connected, the first spline shaft 63 is relatively retracted with respect to the first spline nut 62. On the other hand, in the injection motor 45, by supplying a current of a predetermined frequency to the stator 48,
2 can be advanced. Therefore, an annular bearing retainer 64 is fixed to the rear end of the second rotor shaft 57. On the inner periphery of the bearing retainer 64, a first shaft portion 65 of a ball screw shaft 65 as a rotating body is provided.
a is fitted and fixed. The ball screw shaft 65 is rotatably supported by the drive unit case 11. That is, the ball screw shaft 65 is supported by the bearing 66 and the thrust bearing 68 via the bearing retainer 64 with respect to the rear cover 17. An annular load meter 75 is provided on the rear cover 17.
, The rear cap 77 is fixed by the bolt b6, and the second shaft portion 65b of the ball screw shaft 65 is supported by the bearing 67 with respect to the rear cap 77. An absolute value pulse encoder 85 is provided on the rear cap 77 via a bracket 86. The absolute value pulse encoder 85 is connected to the second shaft portion 65b, detects the rotation speed of the ball screw shaft 65, that is, the rotation speed of the injection motor, and detects the rotation speed of the screw 22 based on the rotation speed of the injection motor. Detect the position.

A ball nut 69 is provided in the second rotor shaft 57 so as to advance and retreat, and the ball nut 69 and the ball screw shaft 65 are screwed together. In this case, the ball nut 69 and the ball screw shaft 65 constitute a ball screw and a movement direction changing means. Therefore, the rotation of the rotor 49 is transmitted to the ball screw shaft 65 via the second rotor shaft 57 and the bearing retainer 64, and the rotational motion is converted into a linear motion, and the ball nut 69 moves forward and backward. The stopper 19 is fixed to the front end of the ball screw shaft 65 by a bolt b13 so that the ball screw shaft 65 does not come off the ball nut 69.

In order to prevent the ball nut 69 from rotating together with the ball screw shaft 65, a sleeve-shaped second spline shaft 71 is fixed to the front end of the ball nut 69 by bolts b11.
The second spline nut 76 fixed to 5 and the second spline shaft 71 are spline-connected. in this case,
The second spline nut 76 and the second spline shaft 7
1 constitutes a second spline unit and a second driving force transmitting means, and in the driving unit case 11 and the bearing box 72, relative movement in the rotation direction is restricted, and relative movement in the axial direction is allowed. Is done. The second spline shaft 71 is connected to the screw 22
Has a length corresponding to the stroke of

A bearing box 7 is provided at the front end of the second spline shaft 71 as third driving force transmitting means.
2 is fixed by bolts b7, and a thrust bearing 73 is provided forward in the bearing box 72.
A bearing 74 is provided rearward. In this case, the bearing box 72 restricts the relative movement in the axial direction of the first spline shaft 63 and the second spline shaft 71, and allows the relative movement in the rotation direction.
Therefore, the first spline shaft 63 is rotatably supported by the thrust bearing 73 and the bearing 74 with respect to the second spline shaft 71 and the ball nut 69.

The rear end shaft 22b of the screw 22 is connected to the front end of the first spline shaft 63 via a first coupling 81 and a second coupling 82.
8, fixed by b9. The first coupling 8
1 is the sleeve 18 as the screw 22 advances and retreats.
Can be slid inside. Further, the first spline shaft 63
At the rear end of the first spline shaft 63, a concave portion 63a is formed so as not to interfere with the head of the bolt b13. Therefore, the axial dimension of the electric injection molding machine can be reduced.

An encoder 84 is connected to the sleeve 18 via a gear train 87, and detects the rotational speed of the sleeve 18, that is, the rotational speed of the motor for measurement. Reference numeral 89 denotes a water-cooled jacket, which is fixed to the front cover 13 by bolts b10.
2 prevents heat from being transmitted from the rear end to the front cover 13.

Next, the operation of the driving section having the above configuration will be described. First, in the injection step, when a current is supplied to the stator 48 of the injection motor 45, the rotor 49 is rotated, and the rotation of the rotor 49 is controlled by the second rotor shaft 5.
7 and the ball screw shaft 6 via the bearing retainer 64
5 and the ball screw shaft 65 is rotated.
At this time, since the second spline nut 76 and the second spline shaft 71 are spline-connected, the ball nut 69 does not rotate. Therefore, a thrust is generated in the ball nut 69, and the ball nut 69 is advanced.

During this time, the weighing motor 44 is not driven, and the rotor 47 is stopped. Therefore,
The first spline shaft 63 disposed in front of the ball nut 69 is advanced without rotating, and advances the screw 22. Thus, the injection motor 4
5 is converted into linear motion by the ball screw shaft 65 and the ball nut 69. As a result, the resin 33 stored in front of the screw 22 can be injected from the injection nozzle 12a.

Next, in the measuring step, the measuring motor 4
When the current is supplied to the stator 46 of No. 4, the rotor 47 is rotated, and the rotation of the rotor 47 is transmitted to the first spline shaft 63 via the first rotor shaft 56, the sleeve 18, and the first spline nut 62, The first spline shaft 63 is rotated. Then, the rotation of the first spline shaft 63 is transmitted to the screw 22, and the screw 22 is rotated. Accordingly, the groove 2
6, the resin 33 moves forward while being melted.
The screw 22 is caused to retreat by a back pressure generated with the advance of the screw.

At this time, since the first spline nut 62 and the first spline shaft 63 are spline-connected, the first spline shaft 63 is relatively retracted with respect to the first spline nut 62. The injection motor 45 is driven while controlling the back pressure of the resin 33 to be measured, and the rotor 49 is rotated in a direction to retract the screw 22. At this time, the load applied in the axial direction of the screw 22 or the like is detected by the load meter 75,
The back pressure can be calculated based on the load. Alternatively, a pressure sensor (not shown) may be provided in the heating cylinder 12, the pressure sensor detects the pressure of the resin 33 in the heating cylinder 12, and the back pressure can be calculated based on the pressure.

When the screw 22 is advanced and retracted in the heating cylinder 12, resin powder may be discharged from the rear end of the screw 22, and foreign matter such as the resin powder may be removed from the first rotor shaft. When a friction sliding portion such as the bearing 51 rotatably supporting the bearing and the engaging portion of the first spline unit enters the friction sliding portion, the friction sliding portion is abnormally worn or galling, resulting in electric injection. This will reduce the durability of the molding machine.

In order to prevent foreign matter from entering each of the friction sliding portions, a foreign matter entry preventing member is provided. That is, as shown in FIG. 1, the sleeve 18 is disposed on the inner periphery of the front portion of the first rotor shaft 56, and the flange portion 18a formed at the front end of the sleeve 18 is connected to the first rotor shaft 56. The front end of 56 is fixed to each other by bolts b5. The front cover 13 has a housing chamber 13a for housing the bearing 51 and the flange 18a. Then, a seal member 91 as a foreign matter intrusion prevention member is attached to the outer peripheral edge of the flange portion 18a, and the lip 91a of the seal member 91 is slid on the inner wall of the housing chamber 13a.

Therefore, even if foreign matter tries to enter the bearing 51, the foreign matter is prevented by the seal member 91. Further, as described above, the front end of the first spline shaft 63 is connected to the rear end shaft 2 of the screw 22 via the first coupling 81 and the second coupling 82.
2b is fixed by bolts b8 and b9. The first
The coupling 81 is slid inside the sleeve 18 as the screw 22 advances and retreats. And the first
A seal member 92 as a foreign matter intrusion prevention member is provided on the outer peripheral edge of the coupling 81.

Therefore, even if foreign matter tries to enter the engaging portion of the first spline unit formed by the first spline nut 62 and the first spline shaft 63, the foreign matter is prevented by the seal member 92. As described above, the screw 22 side and the drive unit are completely shut off by the seal members 91 and 92, so that foreign matter such as resin powder can be frictionally slid in the bearing 51, the engagement portion of the first spline unit, or the like. It is prevented from entering the moving part. Therefore, the friction sliding portion is not abnormally worn or galling. As a result, the durability of the electric injection molding machine is not reduced.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0035]

As described above in detail, according to the present invention, in a foreign matter entry device of an electric injection molding machine, a hollow motor, a rotating body rotated by driving the hollow motor, and It has a screw connected to the rotating body, a friction sliding portion that frictionally slides as the rotating body rotates, and a foreign matter entry preventing member that prevents foreign matter from entering the friction sliding portion.

In this case, foreign matter is prevented from entering the friction sliding portion, so that the friction sliding portion is abnormally worn,
No galling occurs. As a result, the durability of the electric injection molding machine is not reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a drive unit of an electric injection molding machine according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of an injection device according to an embodiment of the present invention.

FIG. 3 is a sectional view of a driving unit of the electric injection molding machine according to the embodiment of the present invention.

[Explanation of symbols]

 44 Metering motor 45 Injection motor 51-54 Bearing 56 First rotor shaft 57 Second rotor shaft 62 First spline nut 63 First spline shaft 64 Bearing retainer 65 Ball screw shaft 69 Ball nut 71 Second spline shaft 76 Second spline nut 91, 92 Seal member

Claims (3)

[Claims] (A) a hollow motor; and (b) a rotating body rotated by driving the hollow motor.
(C) a screw connected to the rotating body, and (d) a friction sliding portion that frictionally slides as the rotating body rotates.
(E) a foreign substance entry device for an electric injection molding machine, comprising: a foreign substance entry preventing member for preventing entry of foreign substances into the friction sliding portion. 2. The foreign matter of the electric injection molding machine according to claim 1, wherein (a) the rotating body is a rotor shaft, and (b) the friction sliding portion is a bearing rotatably supporting the rotor shaft. Ingress device. 3. The rotating body is a sleeve,
The foreign matter entry device for an electric injection molding machine according to claim 1, wherein (b) the friction sliding portion comprises a spline nut fixed to the sleeve and a spline shaft connected to the spline nut.