JPH0473373B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a drive device for imparting rotary motion and reciprocating linear motion in the axial direction, that is, the thrust direction, to a driven object, such as a screw in a plastic kneading extruder.

Prior Art The screw of a kneading extruder rotates and repeats reciprocating motion in the thrust direction, thereby kneading the material while heating it. Therefore,
The drive device of this type of kneading extruder is equipped with a mechanism for reciprocating the screw in the thrust direction in addition to the rotation drive device.

Conventional reciprocating motion mechanisms convert the rotation of the screw into reciprocating rocking motion using a cam crank mechanism.
The swinging motion is converted into a reciprocating linear motion in the thrust direction of the screw. In such a drive mechanism,
Since the rotational movement of the screw and the linear reciprocating movement in the thrust direction are mechanically synchronized, it is difficult to change the movement mode, that is, the stroke and relative position of the reciprocating linear movement. Therefore, according to the prior art, even when the physical properties of the object to be kneaded change, an appropriate operating state, that is, a kneading action cannot be obtained.

OBJECT OF THE INVENTION Accordingly, an object of the present invention is to mechanically separate the rotational motion of a driven object and the linear reciprocating motion in the thrust direction, and to enable the states of these motions to be freely set by electrical automatic control. It is to be.

SUMMARY OF THE INVENTION Therefore, the present invention rotates an output shaft connected to a driven object such as a screw by a main motor, provides a feed screw mechanism on the output shaft movable in the thrust direction, and provides a feed screw mechanism for the output shaft that is movable in the thrust direction. By rotating the feed nut at a fixed position, the output shaft is given reciprocating linear motion in the thrust direction. Here, the driving source of this feed nut is
Powered by servo motor under automatic control.

Incidentally, the amount of displacement of the output shaft in the thrust direction is affected by the rotation of the output shaft itself as well as the rotation of the feed nut. Therefore, the relative rotational difference between the output shaft and the feed nut is detected by a differential gear mechanism that receives the rotations thereof as input. Therefore,
This rotation difference is determined by the following: When the rotation of the main shaft is stopped,
This corresponds to the amount of rotation that should be given to the above-mentioned feed nut. Therefore, the controller of the control system commands the driver of the servo motor to rotate so that the rotation difference detected by the differential gear mechanism becomes a preset target displacement amount with respect to the phase of the output shaft. give. The target displacement amount is given by, for example, a sine wave, depending on the rotation angle (phase) of the output shaft.

The above controller detects the rotation angle of the output shaft and automatically reads the target displacement amount corresponding to the rotation angle from the built-in memory. This target displacement amount can be set freely in advance, so
The movement of the output shaft, that is, the reciprocating linear movement in the thrust direction relative to the rotational movement of the screw, which is the driven object, can be freely set according to the physical properties of the object to be kneaded.

Configuration of the Invention Hereinafter, the configuration of the present invention will be specifically explained based on the drawings.

First, FIG. 1 shows a thrust direction reciprocating drive device 1 of the present invention together with a kneading extruder 2 to be driven. The thrust direction reciprocating drive device 1 includes a gear case 3
An output shaft 4 is provided inside the main motor 5, and a servo motor 6 is provided outside the main motor 5 for giving rotation to the output shaft 4 and a servo motor 6 for giving reciprocating linear motion in the thrust direction, that is, the axial direction, to the output shaft 4. It is equipped with

The output shaft 4 is rotatably supported by front and rear bearings 7 and 8 and slidably in the thrust direction, that is, in the axial direction, and is fitted into a spline sleeve 10 at a spline 9 formed in a part. , and is connected to the feed nut 12 by means of a threaded pair at a portion of the female screw 11 which is fixed to another portion.

The spline sleeve 10 is for transmitting only rotational motion to the output shaft 4, and is rotatably supported by the gear case 3 by ball bearings 13 at its front and rear ends, and rotates around the output gear 14 at its intermediate portion. It is held in a stopped state. The feed nut 12 is for giving linear reciprocating motion in the thrust direction to the output shaft 4, and is fixed to the center of the output gear 15 in a non-rotating state and in a state to receive the thrust. It is rotatably supported by the gear case 3 via front and rear ball bearings 16.

On the other hand, the rotation of the main motor 5 is transmitted to the intermediate shaft 18 by, for example, a timing belt/pulley 17. This intermediate shaft 18 is rotatably supported inside the gear case 3 by a ball bearing 19, and supports a gear 20 and a bevel gear 21 that mesh with the output gear 14. This bevel gear 21 meshes with a bevel gear 22 fixed to a shaft 23. This shaft 23 is rotatably supported by the gear case 3, and has one end connected to the gear 24.
, and is connected to an absolute type encoder 25 at the end.

Further, the servo motor 6 is attached to the outer surface of the gear case 3, and is transmitted to the output gear 15 via a gear 27 of a motor shaft 26 and gears 29, 30 of an intermediate shaft 28. The intermediate shaft 28 is supported by the gear case 3 by a ball bearing 31, and meshes with a bevel gear 33 of a differential gear mechanism 34 by a bevel gear 32 attached to an extended portion thereof. The differential gear mechanism 34 outputs the rotation of the bevel gear 33 on one input side and the rotation difference between the gear 35 on the other input side that meshes with the gear 24 through the detection shaft 36 and gears 37 and 38. , and is transmitted to the encoder 39 for differential detection.

By the way, the kneading extruder 2 to be driven includes a screw 40 to be controlled inside a screw housing 41, which is rotatable and slidable in the thrust direction. This Screw 40
is connected to the output shaft 4 by a coupling 42. The screw housing 41 is equipped with a heater 46 on its outer periphery, a pin 47 that can pass through the notch of the screw 40 inside, and a nozzle 48 that is pressed by hydraulic pressure at the opening at the tip. It is in contact with The material 43 to be kneaded is stored inside the hopper 44 and fed into the base end portion of the screw 40 while being mixed by the agitator 45.

Next, FIG. 2 shows a control device 50 and a speed change control device 51. As shown in FIG. The servo motor 6 is controlled by a servo driver 52. Further, the main motor 5 is controlled to rotate at an arbitrary predetermined speed by a speed change control device 51 that is separate from the control device 50. The encoder 25 and the encoder 39 are each connected to a controller 53.
is connected to the motor driver 52 of the servo motor 6 and the position command memory 49.

Effects of the Invention Next, the effects of the thrust direction drive device 1 will be explained.

First, the speed change control device 51 rotates the main motor 5 at a predetermined speed. At this time, main motor 5
The rotation is transmitted to the spline sleeve 10 via the timing belt pulley 17, intermediate shaft 18, gear 20, and output gear 14. Therefore, the spline sleeve 10 transmits only the rotation to the output shaft 4 while allowing linear movement of the output shaft 4 in the thrust direction. In this way, the output shaft 4 rotates the screw 40 of the kneading extruder 2 at a constant speed.
Rotate.

On the other hand, the controller 53 is connected to the encoder 25
The rotation angle of the output shaft 4 is detected, and at the detected rotation angle, the amount of displacement in the thrust direction applied to the output shaft 4 is sequentially read from the position command memory 49. Such a displacement amount is inputted in advance as a curve, such as a sine wave, for each rotation angle of the output shaft 4.

On the other hand, the differential gear mechanism 34 combines the rotation of the main motor 5, that is, the rotation of the output shaft 4, and the rotation of the servo motor 6.
, that is, the rotation of the feed nut 12, the rotation difference is detected, and the rotation difference is transmitted to the encoder 39. As a result, the encoder 39
The output signal corresponds to the relative rotational difference between the output shaft 4 and the feed nut 12.

Therefore, the controller 53 determines the target displacement amount at a certain rotation angle of the main shaft 4 and the encoder 25.
A rotation command is given to the servo driver 52 of the servo motor 6 based on the difference. As a result, the servo motor 6 rotates the feed nut 12 in order to give the output shaft 4 a target displacement amount in the thrust direction.

For example, if the feed nut 12 is rotating at the same rotation speed as the output shaft 4, the female screw 11 and the feed nut 12
Since there is no relative displacement in the thrust direction between the two, the output shaft 4 rotates without moving in the thrust direction of the screw 40. However, when the feed nut 12 rotates in the same direction at a higher rotational speed than the output shaft 4, the output shaft 4 moves backward together with the screw 40, that is, to the right in the drawing. Conversely, when the feed nut 12 rotates in the same rotational direction as the output shaft 4 but at a lower rotation speed, the output shaft 4 and the screw 40 move in the forward direction, that is, in the left direction in the drawing. Become. In this way, the servo motor 6 can periodically repeat acceleration and deceleration in the same direction as the output shaft 4 and around the same rotational speed as the target displacement amount, for example, along a sine wave curve. As a result, the output shaft 4 repeats reciprocating linear motion in the thrust direction together with the screw 40 due to the screw action of the female screw 11 and the feed nut 12. Moreover, the stroke and relative position of this reciprocating linear motion are controlled by the controller 53.
By changing the data to be input in , you can set it freely.

In this way, the screw 40
are kneaded in a molten state while being sequentially fed through the spiral, and extruded forward from the nozzle 48.
During this time, the pins 47 prevent the material 43 from moving in the feeding direction, thereby applying a shearing force to the material 43 and facilitating the kneading operation. As already mentioned, the notch is provided in the spiral portion of the screw 40, so when the screw 40 is driven by the output shaft 4 and makes reciprocating linear motion in the thrust direction, the pin 4
7 passes through a notch in the helix of the screw, allowing mechanical rotation and reciprocation.
The material 43 after kneading is intermittently discharged to the outside by pushing open the nozzle 48.

Industrial Application Field Although the present invention was developed with the kneading extruder 2 as the driving object, its application is not limited to this.
It can be widely applied to machines driven by this type of motion, such as plastic molding machines and kneading machines in the food field.

Effects of the Invention The present invention has the following effects. The main motor is the rotational drive source for the output shaft, and the servo motor is separately provided as the drive source for the reciprocating linear motion in the thrust direction, so their synchronous or harmonious motion can be adjusted with a high degree of freedom. In addition, since the output shaft generates rotation in the thrust direction by a screw mechanism, reciprocating linear motion can be obtained by the relative rotational movement of the feed nut, eliminating the need for a conventional swinging crank mechanism. First, the drive mechanism can be simplified. Furthermore, since the difference between the rotational motion of the main shaft and the relative rotational motion of the feed nut can be obtained by the differential gear mechanism, the deviation between the actual amount of movement in the thrust direction and the target amount of displacement can be detected mechanically. , accurate feedback control becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the thrust direction reciprocating drive device of the present invention, and FIG. 2 is a block diagram of the control device. DESCRIPTION OF SYMBOLS 1... Thrust direction reciprocating drive device, 2... Kneading extruder to be driven, 3... Gear case, 4... Output shaft, 5... Main motor, 6... Servo motor, 9... Spline, 11... Female thread, 12...
...Feed nut, 25...Encoder, 34...Differential gear mechanism, 39...Encoder, 40...Screw, 50...Control device.

Claims (1)

[Claims] 1. An output shaft that is slidable and rotatably supported in the direction of thrust, a main motor that rotates this output shaft at a predetermined speed, and an output shaft that is connected to the output shaft with a pair of screws and rotatably supported at a fixed position. a reciprocating drive servo motor that rotates the feed nut, a differential gear mechanism that detects the relative rotational difference between the output shaft and the feed nut, and the differential gear. It is characterized by comprising a controller that gives a rotation command to the driver of the servo motor so that the rotation difference detected by the mechanism is a preset target displacement amount with respect to the rotation phase of the output shaft. A reciprocating drive device in the thrust direction.